VERMICOMPOSTING FOR DOMESTIC WASTE SEMINAR

ABSTRACT

One of the main task faced in the country, is the management of solid waste. The concern for its safe disposal is paramount importance for the society. This problem is increasing day by day with an increase in population and with generation of solid waste. Solid waste arising out of domestic, commercial and industrial activities is thrown out. Its unscientific management thereafter leads to serious environmental problems.

In the present study the waste from the canteen and dairy was collected which comprises variety of the materials like food waste and other vegetable waste. This waste was than mixed with some sand and cow dung in proportion of 50-50 %. The plastic bins were prepared. Earthworms with waste were added in the bin. The samples were analyzed after one month and found favorable results. Then now the study is further extended for industrial waste. The organic waste form the industry is to collected and composed in plastic bin and surface bed system. After composting complete the samples will be analyzed to know the nutrients concentration and compared with the standard vermi compost and synthetic fertilizers. The experiments will be performed at the campus by following the same procedure given in the literature for both plastic bin and for surface bed system.  The results will be discussed in the paper. By this method the solid waste generated in the industry can be reuse as a fertilizer.

Key words: Earthworms, Vermicomposting, Bioconversion, solid waste, safe disposal

INTRODUCTION: One of the major tasks faced in the country is, the management of solid wastes the concern for its safe disposal is of paramount importance for society.  This problem is getting more complex day by day with an increase in urban population and with the generation of new types of wastes.  Solid wastes arising out of domestic, commercial and industrial activities are thrown out of site from the premises to the nature. Its unscientific management thereafter leads to serious environmental problems.

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smart materials seminar

 

                                      

ABSTRACT                                                                                                                                                 

This paper will provide an overview of the smart materials. Smart material can be defined as material that can significantly change their mechanical properties (such as shape, stiffness, and viscosity), or their thermal, optical, or electromagnetic properties, in a predictable or controllable manner in response to their environment. Such materials have the ability to change shape or size simply by adding a little bit of heat, or to change from a liquid to solid almost instantly. Each individual type of smart material has a different property such as volume, viscosity, and conductivity which can be significantly altered.

The various types of smart material are also presented in the paper. To get the clear idea about the smart materials, its definition and types are explained briefly. Some of the types of these include piezoelectric materials, magneto-rheostatic materials, electro-rheostatic materials, and shape memory alloys piezoelectric, Varieties of smart materials already exist, and research is being carried out extensively to device new materials.

Applications of various types of smart materials are clearly explained. Some of applications of already existing smart materials are studied. The expectations of the smart materials and the predictions of future applications have been presented on the later part of the paper. And it is concluded that the application of smart material in future becomes a trend in various fields in engineering.

KEYWORDS

Piezoelectric materials, magneto-rheostatic, electro-rheostatic materials, shape memory alloys.

INTRODUCTION

The development of durable and cost effective high performance construction materials and systems is important for the economic well being of a country mainly because the cost of civil infrastructure constitutes a major portion of the national wealth. To address the problems of deteriorating civil infrastructure, research is very essential on smart materials. This paper highlights the use of smart materials for the optimal performance and safe design of buildings and other infrastructures particularly those under the threat of earthquake and other natural hazards. The peculiar properties of the shape memory alloys for smart structures render a promising area of research in this field.

Everyday materials have physical properties, which cannot be significantly altered; for example if oil is heated it will become a little thinner, whereas a smart material with variable viscosity may turn from a fluid which flows easily to a solid. Varieties of smart materials already exist, and are being researched extensively. These include piezoelectric materials, magneto-rheostatic materials, electro-rheostatic materials, and shape memory alloys. Some everyday items are already incorporating smart materials (coffeepots, cars, the International Space Station, eyeglasses) and the number of applications for them is growing steadily.

Each individual type of smart material has a different property which can be significantly altered, such as viscosity; volume Smart materials have one or more properties that can be dramatically altered. Most, and conductivity. The property that can be altered influences what types of applications the smart material can be used for.

1. PIEZOELECTRIC MATERIALS

Piezoelectric materials have two unique properties which are interrelated. When a piezoelectric material is deformed, it gives off a small but measurable electrical material it experiences a significant increase in size (up to a 4% change in volume)

Piezoelectric materials are most widely used as sensors in different environments. They are often used to measure fluid compositions, fluid density, fluid viscosity, or the force of an impact. An example of a piezoelectric material in everyday life is the airbag sensor in your car. The material senses the force of an impact on the car and sends and electric charge deploying the airbag.

2. ELECTRO-RHEOSTATIC AND MAGNETO-RHEOSTATIC

Electro-rheostatic (ER) and magneto-rheostatic (MR) materials are fluids, which can experience a dramatic change in their viscosity. These fluids can change from a thick fluid (similar to motor oil) to nearly a solid substance within the span of a millisecond when exposed to a magnetic or electric field; the effect can be completely reversed just as quickly when the field is removed. MR fluids experience a viscosity change when exposed to a magnetic field, while ER fluids experience similar changes in an electric field. The composition of each type of smart fluid varies widely. The most common form of MR fluid consists of tiny iron particles suspended in oil, while ER fluids can be as simple as milk chocolate or cornstarch and oil.

MR fluids are being developed for use in car shocks, damping washing machine vibration, prosthetic limbs, exercise equipment, and surface polishing of machine parts. ER fluids have mainly been developed for use in clutches and valves, as well as engine mounts designed to reduce noise and vibration in vehicles.

3. SHAPE MEMORY ALLOYS (SMA) 

Shape memory alloys (SMA's) are metals, which exhibit two very unique properties, pseudo-elasticity, and the shape memory effect

The term shape memory refers to the ability of certain alloys (Ni – Ti, Cu – Al – Zn etc.) to undergo large strains, while recovering their initial configuration at the end of the deformation process spontaneously or by heating without any residual deformation .The particular properties of SMA’s are strictly associated to a solid-solid phase transformation which can be thermal or stress induced. Currently, SMAs are mainly applied in medical sciences, electrical, aerospace and mechanical engineering and also can open new applications in civil engineering specifically in seismic protection of buildings. 

Its properties which enable them for civil engineering application are 

 1. Repeated absorption of large amounts of strain energy under loading without permanent     deformation. Possibility to obtain a wide range of cyclic behavior –from supplemental and fully reentering to highly dissipating-by simply varying the number and/or the characteristics of SMA components.

2. Usable strain range of 70%

3. Extraordinary fatigue resistance under large strain cycles

4. Their great durability and reliability in the long run.

4. ADVANTAGES AND DISADVANTAGES OF SMA’S

Some of the main advantages of shape memory alloys include:

·         Bio-compatibility

·         Diverse Fields of Application

·         Good Mechanical Properties (strong, corrosion resistant)

There are still some difficulties with shape memory alloys that must be overcome before they can live up to their full potential. These alloys are still relatively expensive to manufacture and machine compared to other materials such as steel and aluminum. Most SMA's have poor fatigue properties; this means that while under the same loading conditions (i.e. twisting, bending, compressing) a steel component may survive for more than one hundred times more cycles than an SMA element.

5. APPLICATIONS

1. Substitute for steel:

It is reported that (4) the fatigue behavior of CuZnAl-SMA’s is comparable with steel. If larger diameter rods can be manufactured. It has a potential for use in civil engineering applications. Use of fiber reinforced plastics with SMA reinforcements requires future experimental investigations.

2. Carbon fiber reinforced concrete:

Its ability to conduct electricity and most importantly, capacity to change its conductivity with mechanical stress makes a promising material for smart structures .It is evolved as a part of DRC technology (Densified Reinforced Composites).The high density coupled with a choice of fibers ranging from stainless steel to chopped carbon and Kevlar, applied under high pressure gives the product with outstanding qualities as per DRC technology. This technology makes it possible to produce surfaces with strength and durability superior to metals and plastics.

3. Smart concrete:

A mere addition of 0.5%specially treated carbon fibers enables the increase of electrical conductivity of concrete. Putting a load on this concrete reduces the effectiveness of the contact between each fiber and the surrounding matrix and thus slightly reduces its conductivity. On removing the load the concrete regains its original conductivity. Because of this peculiar property the product is called “Smart Concrete”. The concrete could serve both as a structural material as well as a sensor.

The smart concrete could function as a traffic-sensing recorder when used as road pavements. It has got higher potential and could be exploited to make concrete reflective to radio waves and thus suitable for use in electromagnetic shielding. The smart concrete can be used to lay smart highways to guide self steering cars which at present follow tracks of buried magnets. The strain sensitive concrete might even be used to detect earthquakes.

4. Active structural control against wind:

Aerodynamic control devices to mitigate the bi-directional wind induced vibrations in tall buildings are energy efficient, since the energy in the flow is used to produce the desired control forces. Aerodynamic flap system (AFS) is an active system driven by a feedback control algorithm based on information obtained from the vibration sensors. The area of flaps and angular amplitude of rotation are the principal design parameters. 

6. THE FUTURE

The development of true smart materials at the atomic scale is still some way off, although the enabling technologies are under development. These require novel aspects of nanotechnology (technologies associated with materials and processes at the nanometer scale, 10-9m and the newly developing science of shape chemistry.

Worldwide, considerable effort is being deployed to develop smart materials and structures. The technological benefits of such systems have begun to be identified and, demonstrators are under construction for a wide range of applications from space and aerospace, to civil engineering and domestic products. In many of these applications, the cost benefit analyses of such systems have yet to be fully demonstrated.

The concept of engineering materials and structures which respond to their environment, including their human owners, is a somewhat alien concept. It is therefore not only important that the technological and financial implications of these materials and structures are addressed, but also issues associated with public understanding and acceptance

CONCLUSION

The technologies using smart materials are useful for both new and existing constructions. Of the many emerging technologies available the few described here need further research to evolve the design guidelines of systems. Codes, standards and practices are of crucial importance for the further development.

removal of cod of diary effluent seminar

Environmental problem is the major concern for any industry and there is a great need to that along green lines.  Sangam Dairy being one of the most famous and widespread dairies in India, it produces wide spectrum of milk products. The Chemical Oxygen Demand (COD) levels of effluent water of this industry with MIF treatment were found to be around 900 ppm.

The main objective of the present study is to minimize the COD level to the required level stipulated by the environmental standards by employing various surface active materials like ferric chloride, alum and commercial coal and to evaluate various parameters effecting the COD level during the treatment.  Initial and final COD were determined before and after the treatment.  Characteristics of COD levels were determined by using open reflux method. 

From the COD data for all samples, comparison of various surface-active materials was carried to suggest the efficient surface-active material for ETP.  The optimum time of contact, dosage and pH were found to be 40min, 13.5g/l and 9.18 respectively for the operations using ferric chloride.  The optimum time of contact, dosage and pH were found to be 90min, 15g/l and 9.18 respectively for the operations using alum.  The optimum time of contact, dosage and pH were found to be 80min, 100g/l and acidic medium respectively for the operations using commercial coal.  It has been observed that ferric chloride is the best suitable material compared to alum and commercial coal.  However, commercial coal is cheaper and it can also bring down the COD level with in PCB norms.  So, it is advisable to use commercial coal for the reduction of COD.

INTRODUCTION:

Sangam Dairy is situated at Vadlamudi, 15km to Guntur city in Andhra Pradesh. This is run by Guntur District milk producers mutually aided Co-Operative society. Sangam Dairy collects on average one-lakh liters of milk per day. How ever in seasons it handles up to 2.5 lakh liters per day.

Sources of Waste Water in the Diary

        The liquid waste from a large dairy originates from the following section or plants:

            Receiving station        Condensed milk plant

Bottling plant              Dried milk plant

Butter plant                 Bottle and can washing plants

            At the bottling plant the raw milk arrived by the receiving station is stored. The processing includes cooling, clarification, filtration, pasteurization and bottling.

            The dairy wastes are very often discharge intermittently. The nature and composition of waste also depend on the type of products produced and the size of the plant.  The typical Indian dairy handling about 3, 00,000 to 4, 00,000 liters of milk in a day.

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POLYMER ELECTROLYTIC FUEL CELL

BACKGROUND
   

    Fuel cells convert the chemical energy of fuels directly into electricity. The principle of the fuel cell was developed by William Grove in 1839. Already around 1900 scientists and engineers were predicting that fuel cells would be common for producing electricity and motive power within a few years. That was roughly 100 years ago. Contrast this with the roughly 2 years that it took Nikolaus Otto to bring his Otto cycle 4-stroke internal combustion engine from the invention stage to a commercial success.

HOW A FUEL CELL WORKS:

    A fuel cell works similar to a battery. In a battery there are two electrodes which are separated by an electrolyte. At least one of the electrodes is generally made of a solid metal. This metal is converted to another chemical compound during the production of electricity in the battery. The energy that the battery can produce in one cycle is limited by the amount of this solid metal that can be converted. In the fuel cell the solid metal is replaced by an electrode that is not consumed and a fuel that continuously replenishes the fuel cell. This fuel reacts with an oxidant such as oxygen from the other electrode. A fuel cell can produce electricity as long as more fuel and oxidant is pumped through it.

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PHENOL REMOVAL FROM INDUSTRIAL EFFLUENTS USING EMULSION LIQUID MEMBRANE TECHNIQUE

ABSTRACT

Removal of phenol from industrial effluents was studied using the emulsion liquid membranes. A multiple W1/O/W2 emulsion is prepared where the intermediate "O" represents oil phase acting as membrane; W1 and W2 are aqueous phases

W₂ is the external aqueous phase from which phenol is to be removed and Wl is the aqueous NaoH phase which receives the phenol that got transported across the membrane oil phase. Emulsifier used in preparing the emulsion is Span 80

The effect of various parameters such as stirring speed, oil phase to aqueous phase ratio in emulsion, surfactant concentration, internal reactive phase concentration in the emulsion, treat ratio (ratio of emulsion to waste water phase), initial phenol concentration, effect of change in membrane phase, temperature on the rate of removal of phenol were studied

Studies pertaining to selling of emulsions due to penetration of water into the emulsion were also conducted and it is found that this phenomenon is primarily responsible for breakage of the dispersed emulsion drops during the operation. With the help of data obtained from this work an optimal recipe for the membrane can be identified which could be conveniently used to design liquid emulsion membrane based separation systems for phenol removal from the waste water streams

INTRODUCTION

Phenol is key effluent from various industries like pharmaceuticals, pesticides & paper and pulp industries, dyes manufacturing, synthetic chemicals

Phenol is a colorless-to-white/ light pink solid when pure; however, the commercial product, which contains some water, is a liquid. Phenol has a distinct odour that is sickeningly sweet and tarry

Techniques used for removal of phenol from waste water

Emulsion liquid membranes

Other than the above process Adsorption, Solvent extraction, Electrochemical reduction

Biological degradation can also be used for phenol removal

Effects of phenol on living organisms:

All forms of phenol cause irritation, and acute toxic effects of phenol most often occur by skin contact. Even dilute solutions. (1% to 2%) may cause severe burns if contact is prolonged. Toxicity can result from skin or eye exposures. Phenol vapor and liquid penetrate the skin with absorption efficiency approximately equal to the absorption efficiency by inhalation. In one case, death occurred within 30 minutes after skin contact. Children are more vulnerable to toxicants absorbed through the skin because of their relatively larger surface area: body weight ratio.

As little as 50 to 500 mg has been fatal in infants. Deaths in adults have resulted after ingestions of 1 to 32 g. Phenol is corrosive and causes chemical burns at the contact site. Other symptoms include nausea, vomiting, diarrhea, profuse sweating, and hypotension.

Severe effects of phenol exposure:

As a corrosive substance, phenol denatures proteins and generally acts as a protoplasmic poison. Phenol may also cause peripheral nerve damage. Systemic poisoning can occur after inhalation, skin contact, eye contact, or ingestion. Damage to the nervous system is the primary cause of death from phenol poisoning.

 Membranes:

The purpose of adopting the membrane process could be either concentrating the feed by preferential permeation of sol vent or diluting the feed by preferential permeation of solute.

Membrane is defined as "A Selective barrier between two phases", and the term "Selective" being inherent to a membrane or a membrane process or it is defined as "A thin film (0.1 to 0.4mm) of polymeric or inorganic material capable of preferentially allowing some components of the feed mixture to pass through it compared to other components.

Classification of membranes:

The other  basic  type of classifying membranes  is  by  separation  is porous, non-porous and carrier membranes

Generally speaking membranes can be classified as follows

•              Porous membranes

•              Dense membranes

•              Carrier membranes

•              Composite membranes

•              Insitu formed membranes

•              Ion exchange membrane

•              Atmospheric membranes and

•              Redox membranes

Multiple emulsions as Lm's:

The liquids which are immiscible with each other in the membrane technology are usually water and oils. The formation of an emulsion is favored fundamentally by a reduction of the interfacial tension between the two immiscible liquids. The edition of a surface active material (surfactant) causes this desired reduction. A surfactant molecule must have an amphiphilic molecular structure, such that one part of the molecule is lyophilic (non-polar structure). The hydrophilic part of the surfactant molecule resides in water and the lyophilic part in the oil

Good .surfactants can reduce the interfacial tension by a factor of 5 or 10.    In general, the surfactant dissolves better in one of the two liquids (oil and water) as a result of which the surface tension of that substance is strongly reduced and greater mobility is to be expected.

The emulsion liquid membrane (ELM) as a selective technique has large potential for application

in wastewater treatment. ELM technique is applied both for waste waters containing organic (or) inorganic pollutants and with pollutant mixtures [3]. This method is especially applicable for heavy metal separation from aqueous solutions. In addition, the treated water can be recycled in the process. The membrane method has been applied to treat water containing ferrous and non-ferrous metals, alkaline metals, radioactive elements, rare metals etc.

Elms are usually multiple emulsions of the water/oil/water type. To obtain this, a fine emulsion of the stripping phase in the membrane phase is produced and stabilized by a surfactant. The resulting water-in-oil emulsion is then dispersed by gentle stirring in the feed solution to create a double emulsion

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Hematopoietic Stem Cell Transplantation

All blood cells arise from a type of cell called Hematopoietic stem cell. Stem cells have received a great deal of publicity as lately, due both to recent achievements in their isolation and cultivation and their potential widespread therapeutic uses. A simple definition of stem cells is that they have the capacity both to self-renew and to generate differentiated progeny.  This means that they can generate undifferentiated daughter cells are committed along a certain developmental pathway. In this presentation, we would like to communicate about the different clinical uses of Hematopoietic stem cell transplantation in various disease conditions like SCID, Sickle cell anemia and other cancers.

Introduction:

Stem cells have two important characteristics that distinguish them from other types of cells. First, stem cells are unspecialized cells that are capable of self-renewal. Second, under certain physiologic or experimental conditions, stem cells can differentiate into cells with special functions. Scientists primarily work with two kinds of stem cells: embryonic stem cells and adult stem cells that each have different functions and characteristics ^[4-6].  Embryonic stem cells are a type of Pluripotent stem cell derived from the inner cell mass of the blastocyst. They are primitive and undifferentiated cells that have the potential to become a wide variety of specialized cell types. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are normally lost or damaged by injury or disease.  Pluristem has decided to work with adult stem cells, focusing on the expansion of Pluripotent Hematopoietic Stem Cells (HSCs). Bone marrow is the spongy tissue found in the cavities of the body’s bones that contains special stem cells, called hematopoietic stem cells (HSC). Each type of blood cell begins its life as a hematopoietic stem cell. The stem cells divide and differentiate to form the various cells that are later found in our blood and immune systems. These cells include: leukocytes, lymphocytes, erythrocytes and Platelets that are responsible for blood clotting.

 HSCs have a greater self-renewal and differentiation capacity than any other adult tissue and hold the promise of being able to repair or replace damaged cells and tissues. A cardinal property of hematopoietic stem cells is their ability to divide without significant alteration of their proliferative potential or differentiation state. The first demonstration that such stem cell self-renewal divisions can occur in vitro (albeit without a net increase in their numbers) made use of retroviral marking to identify the clonal progeny in multiple recipients of individual hematopoietic stem cells that had been amplified in 4-week-old long-term cultures (LTC)^[1]. Subsequent attempts to improve the output of stem cells in these cultures by using various cell lines as feeders have allowed input numbers to be maintained, but a net expansion has not been achieved^[2-4]. Within the hematopoietic system, Pluripotent HSCs are the only cells with extensive capacities to expand, differentiate and self-renew. These HSCs are exclusively required for hematopoietic reconstitution following transplantation and serve as a primary target for gene therapy. In spite of the key role of HSCs in maintaining the hematopoietic system, their extremely low frequency in the hematopoietic tissue, as well as the limited ability to maintain or expand undifferentiated stem cells under ex vivo conditions, not only remains a major drawback to essential clinical applications of these cells, but also reflects the current unavailability of, and the need for, novel stem cell regulators.

Sources of hematopoietic stem cells:

The primary source of hematopoietic stem and progenitor cells for use in autologous and allogeneic transplantation has been bone marrow. More recently, use of peripheral blood as a source of these cells has increased. This product is referred to variously as peripheral blood stem cells (PBSC), peripheral blood progenitor cells (PBPC), or stem cells. Although each cell source used for hematopoietic transplantation contains stem cells, when the term stem cell is used without a qualifier, it usually refers to PBSC. Table 1 lists the major sources of hematopoietic stem cells used in transplantation, with the cellular characteristics of each. The use of PBSC has advantages and disadvantages, and the relative balance between these differs, depending on the type of transplant being performed and the disease state being treated. The majority of transplantable HSCs in adults come from adult donor bone marrow or mobilized peripheral blood.  A new and very effective source of transplantable and lasting HSCs comes from umbilical cord blood (CB).  Today, there is a tremendous amount of focus on research, development and business in the area of cord blood innovations. The collection of cord blood is simple and non-invasive. CB is drawn from the umbilical cord after birth, before the placenta is discharged.  As opposed to working with embryonic stem cells, CB is not ethically or controversially charged.  It is also important to note that there is no difference in the functionality of hematopoietic stem cells from bone marrow, mobilized peripheral blood or umbilical cord blood. In the last few years, a new industry has evolved for the collection and storage of cord blood. With the increased development and use of this extraordinary source of HSC for BMT, the number of cord blood banks is rapidly increasing.

Hematopoietic Stem Cell Transplantation^[1-3] is a procedure based on a very simple principle. First a patient is identified who has a potentially lethal disease (e.g. acute myeloid leukemia or beta thalassaemia major). This disease should be such that it can be eradicated by high dose chemoradiotherapy. Such treatment is highly toxic and will invariably lead to permanent destruction of hematopoietic stem cell - i.e. the body's blood forming cells. Thus the potentially curative therapy can only be used if new normal hematopoietic stem cells can be infused and made to work in the patient's body. Such normal blood stem cells are harvested from a donor and reinfused into the patient (after being given the potentially curative chemo-radiotherapy)^[5,6,8]. HSCT is a unique mode of therapy in the field of oncology that

1. it is the most intense form of treatment followed by medical oncologists.

2. it exposes the entire human body to potentially life threatening consequences because this is the only hope of cure.

3. it is the only transplantation procedure which does not require a surgeon.

Who can have a transplant? To be eligible for any form of bone marrow transplant a patient's general health must be good enough to withstand very high dose treatment with anti- cancer drugs and radiation. One of the major factors predicting the risks of transplantation is the age of the patient. Younger patients tend to have a far better chance of success than older patients and less risk of a transplant related death. Most transplant centres will not carry out allogeneic transplants on patients over the age of about 55 years, in some centres the limit is set at 50 years. It is usually acceptable to perform autologous transplants on older patients because the risk is not so great. 

Indications for transplant: Acute leukaemia, Acute lymphoblastic leukaemia, Acute myeloid leukaemia, Chronic lymphocytic leukaemia, Chronic myeloid leukaemia, Hodgkin's disease, Non-Hodgkin's lymphoma, Multiple myeloma, myelodysplastic syndromes and myelofibrosis.

The transplant procedure: Before a patient can receive a transplant their own marrow and immune system must be destroyed with high doses of drugs with or without total body irradiation (TBI). This is necessary even in patients with aplastic anaemia in whom the marrow appears to have already failed. This preparation is called conditioning treatment. There are several different conditioning regimens (a regimen is a specific combination of drug and radiation treatment). For autologous transplantation a regimen called BEAM is frequently used, this is a combination of several drugs given over a period of five days. For myeloma melphalan is frequently used, with or without TBI. Conditioning for allogeneic transplant is either with busulphan and cyclophosphamide or cyclophosphamide with TBI.  Because the chemotherapy used is often at high dose and is given intravenously a tube called a Hickman line is placed under the skin of the chest and into a vein. This is often done in the operating theatre where an X-ray machine can be used to ensure it is correctly inserted. Local painkillers and a sedative are given and it is not painful. 

Hematopoietic stem cells in circulation: Presence of circulating CD 34 +ve stem cells in humans has been known since 1971. However their number is too small to be of clinical use for transplantation (being less than 0.5% in adults). With the advent of recombinant human hematopoietic growth factors, we now have a method to mobilise them (make them come out of the marrow into circulation) in sufficient number for clinical use. Initially HSCTs were performed only in the autologous setting. Now many centres, including in India, are also performing allogenetic HSCTs^[8]. As an alternate to mobilised HSCs, AIIMS, New Delhi has also used unprocessed whole blood transplantation for multiple myeloma. The ideal mode of counting CD34+ve cells is by flowcytometry currently available at most transplant centres in India. About 4 x 106 CD 34+ve cells/ kg body weight of the recipient (minimum of 3 x 106 CD 34+ve cells/ kg) must be collected so that there is a good chance of success.

Major risks after Hematopoietic stem cell transplantation: Patients who undergo these transplantation may experience short-term side effects such as nausea, vomiting, fatigue, loss of appetite, mouth sores, hair loss, and skin reactions. Additionally, patients receiving stem cells may experience nausea and vomiting while receiving the transplant, and chills and fever during the first 24 hours after the transplant. Potential long-term risks include infertility (the inability to produce children); cataracts (clouding of the lens of the eye, which causes loss of vision); secondary (new) cancers; and complications in the liver, kidneys, lungs, and/or heart. With allogeneic transplantation, a complication known as graft-versus-host disease (GVHD) sometimes develops. GVHD can generally be treated with steroids or another immunosuppressive agent. Clinical trials are being conducted to find ways to prevent GVHD from occurring.

Gene Therapy:

In gene addition the whole emphasis is on normal cells where a new gene is added to confer a survival advantage. For example the hematopoietic cells can be made more resistant to the therapeutic consequences of myelosuppression. Gene transfer is used for several indications like repair of mutations. For instance replacing mutated p53 with the normal functioning counterpart in lung cancer leads to a higher response rate (mechanisms involved in this and other potential beneficial effects include increased tumor sensitivity, host sensitivity and host response to therapy as well as gene marking). Certain drugs need activation by enzymes before they become active. The classical examples are gancyclovir, which requires phosphorylation with thymidine kinase. Cells that are transfected with genes for the corresponding enzymes will specifically become susceptible to the toxic effects of these drugs and can be targeted in vivo for selective elimination. In the hematopoietic transplantation setting its immediate application would be in the use of donor lymphocyte transfusions. Such DLT are commonly used for cytogenetic or clinical relapse following allogeneic BMT for its graft v/s leukemia effect. However it has the potential to cause life threatening GVHD and aplastic anemia. Such donor lymphocytes can be transfected with the thymidine kinase gene. Currently clinical trials using gene therapy and hematopoietic transplantation are ongoing for Gene marking (no therapeutic benefit to patient),ADA SCID,X SCID,Chronic Granulomatous Disease,Goucher's Disease, Fanconi's Anemia.

Conclusion:

Hematopoietic stem cell transplantation is by no means an ideal mode of therapy. It is currently the only available curative mode of treatment for several oncological ailments.  However, in the future, Gene therapy and stem cell research is expected to change the way we cure patients completely changing the application of HSCT. Ethical problems are the main barriers to treat many diseases using Hematopoietic Stem Cell Transplantation.  

Existing centres need to focus on the development of regimen/ strategies tailored to our needs. For instance, cancers are diagnosed very early in our population. They are in the most productive phase of their lives and are fit to tolerate dose intensive therapy. Hence they should be subject to strategies that lead to a curative outcome.

References:

1.      Cutler C, Antin JH: Peripheral Blood Stem Cells for Allogeneic Transplantation: A Review. Stem Cells 2001 Mar; 19(2): 108-117.

2.      Gorlin JB, Humphreys D, Kent P, et al: Pediatric large volume peripheral blood progenitor cell collections from patients under 25 kg: a primer. J Clin Apheresis 1996; 11(4): 195-203.

3.      Grupp SA, Stern JW, Bunin N, et al: Tandem high-dose therapy in rapid sequence for children with high-risk neuroblastoma. J Clin Oncol 2000 Jul; 18(13): 2567-75.

4.      Ketterer N, Salles G, Raba M, et al: High CD34(+) cell counts decrease hematologic toxicity of autologous peripheral blood progenitor cell transplantation. Blood 1998 May 1; 91(9): 3148-55

5.      Philip T, Guglielmi C, Hagenbeek A, et al: Autologous bone marrow transplantation as compared with salvage chemotherapy in relapses of chemotherapy-sensitive non-Hodgkin's lymphoma. N Engl J Med 1995 Dec 7; 333(23): 1540-5.

6.      Powles R, Mehta J, Kulkarni S, et al: Allogeneic blood and bone-marrow stem-cell transplantation in haematological malignant diseases: a randomised trial. Lancet 2000 Apr 8; 355(9211): 1231-7.

7.      Schmitz N, Linch DC, Dreger P, et al: Randomised trial of filgrastim-mobilised peripheral blood progenitor cell transplantation versus autologous bone-marrow transplantation in lymphoma patients. Lancet 1996 Feb 10; 347(8998): 353-7.

8.      Siena S, Schiavo R, Pedrazzoli P, Carlo-Stella C: Therapeutic relevance of CD34 cell dose in blood cell transplantation for cancer therapy. J Clin Oncol 2000 Mar; 18(6): 1360-77.