Biodegradable Polymers and their Applications: A Review.

Polymers have an endless scope due to their flexibility, amendment, and modification with the organic and inorganic compounds. There is an intense competition between natural and synthetic biodegradable polymers concerning biodegradability and compatibility with modern technology. Biodegradable polymers play a significant role in sustaining humanity on the earth due to nonenvironmental hazards. These polymers play a crucial role in biomedicine technology, such as tissue engineering, preparation of different scaffolds, drug delivery systems, industrial sector, agriculture, and food packaging. Here, we probed on various applications, challenges, and the limitations of biodegradable polymers in life.

Expanding role of a blood center.

MATERIALS AND METHODS: The study was performed on prospective donors who reported to the Department of Transfusion Medicine. Individuals deferred due to hypertension contributed the study population. They were compared with age and sex matched donor controls. Demographic details were recorded in a proforma. On identification of a hypertensive individual, consequent two comparable donors were taken as controls with a total of 50 hypertensive subjects. Hypertensive status of the subjects were assessed based on the criteria formulated by the WHO-ISH and US Seventh Joint National Committee report on prevention, detection, evaluation and treatment of high blood pressure. RESULTS: About 0.95% of healthy blood donors had undetected hypertension. Mean age at detection of hypertension in the study group was 35.44 ± 7.69 years. Higher BMI was observed in the hypertensive group compared to normotensive control group with P value significant at 0.0001. CONCLUSION: About 1% of healthy individuals were found to have undetected hypertension. Though the study was not designed to determine the prevalence of hypertension in the region, it is a rough estimate of the proportion of undetected hypertension in the local population as donors are considered as representative of healthy population.

Blocked D phenomenon, a rare condition with Rh D haemolytic disease of newborn - a case report.

Accurate Rh testing can be difficult if the red cells are heavily coated with IgG anti D antibodies - a phenomenon called blocked D. Repeatedly, Rh D negative blood group report was obtained in a newborn male baby with severe haemolytic disease and features of kernicterus born to a 2nd gravida B Rh D negative mother. On investigation, the baby was grouped as B Rh D negative by direct grouping, but after elution, D antigen was detected and phenotyped as CcDe. Antibody was identified as anti D. All D antigens of the baby were fully saturated with anti D leaving any antigen to bind with antisera. Direct Coombs test was strongly positive even after three exchange transfusions. The baby also had free antibody apart from the red cell bound and the red cell eluate, gave a titre of 512. The mother was grouped as B Rh D negative and phenotyped as ce. She had IgM and IgG class of anti D with titres 32 and 1024 respectively. She also had IgM anti C (only in neat) and IgG anti-A with a titre of 512.

Suitability of measurement of swirling as a marker of platelet shape change in concentrates stored for transfusion.

Platelet discoid shape is known to correlate with in vivo viability after transfusion. Measurement of shape change requires invasive sampling and laborious assays, which is difficult to perform in a blood transfusion center as a routine test for quality control of stored platelets. The objective of this study was to establish suitability of swirling assessment in stored platelet suspension as a routine test for quality check, by comparing platelet shape change measurement carried out in parallel. The study was done in two types of bags obtained from different manufactures (Groups 1 and 2). Platelet concentrates (PC) were stored for 120 h and samples drawn at 24-h intervals, optical analysis at 540 nm was carried out to quantify shape change in response to an agonist adenosine diphosphate (ADP). The same bags were subjected to swirling assessment, by two blood bank personnel independently and graded as positive (+, ++, +++) or as negative, based on the silky appearance of the suspension. Swirling negative platelets were prepared by storing platelets at 4 degrees C for 24 h and were compared with swirling positive platelets. Other parameters studied in the samples drawn at 24-h intervals were platelet count, mean platelet volume, and blood gases. Swirling assessment results correlated well with shape change measurement at each study period with a P value significant at 0.02 and 0.04 for group 1 and 2 bags, respectively. In the negative swirling controls, extent of shape change was lower than the extent in test bags, showing reduced capacity to respond to ADP at 4 degrees C. The results of the study indicate that by simple swirling measurements, stored PC can be monitored for loss of discoid shape before they are transfused. Gas tension and pH were with in permissible limits. Therefore, inspection of swirling can be a reliable method of quality control as it correlates with platelet function. The platelets that retain the discoid shape in vitro at the time of transfusion are expected to be functional in vivo.

Screening for T cell-eliciting proteins of Japanese encephalitis virus in a healthy JE-endemic human cohort using recombinant baculovirus-infected insect cell preparations.

The analysis of cell-mediated immune responses in virus-exposed but healthy individuals may contribute to define the features of the T cell response associated with resistance. We report, for the first time, on adaptive T cell responses to 5 largest of the 10 proteins that together constitute 76% of the coding potential of the Japanese encephalitis virus (JEV) genome in a naturally exposed healthy JE-immune human cohort. Fixed and sonified whole cell preparations of insect cells individually expressing recombinant prM, E, NS1, NS3 and NS5 proteins of JEV were used in vitro to stimulate lymphocytes from individuals who had experienced subclinical JEV infections. NS3-specific memory T cells were detected in up to 86% of the JEV-infected cohort whereas prM, E and NS1 each elicited reactions in approximately 45% among individuals tested, suggesting that NS3 is an important target for JEV-specific cell-mediated immune responses. Responses to NS5, the largest viral protein were in contrast the poorest, seen in only 13% of the cohort. Moreover, NS3 stimulated interferon-gamma production in both CD4(+) and CD8(+) T cells indicating that a Th1 immune response to the NS3 protein may be a critical determinant of immune control of JEV infection.

Haemolysin test for characterization of immune ABO antibodies.

BACKGROUND & OBJECTIVES: Antibodies with haemolytic properties are common within the ABO system. These lytic antibodies are immunoglobulin G (IgG) and in high titres cause haemolysis during blood transfusion. Information on Immunoglobulin types and concentration of ABO haemolysins in Indian population is lacking. The present study was undertaken to know the usefulness of haemolysin test for characterization of immunoglobulin class of ABO antibodies. METHODS: Serum samples from 187 O group blood donors were screened for A and B haemolysins. Thirty five samples were treated with dithiothretiol (DTT) for characterization of Ig class. Antibody titre was compared with grade of haemolysis. RESULTS: Of the 51 strongly haemolytic serum samples, 32 (62.8%) had IgG titres of > or = 64 after treatment with DTT. There was significant association (P<0.05) between grade of haemolysin and anti B IgG titre. INTERPRETATION & CONCLUSION: Haemolysin test was found to be a useful screening test to identify group O donors with high levels of IgG anti A and/or anti B for blood transfusion purposes.

Clinically significant autoantibodies--a case report.

Auto antiA1 and anti H was found in the serum of a patient admitted in this hospital for intracardiac repair of Ventricular Septal defect (VSD). Blood was grouped as A1 positive with discrepant cell and serum grouping due to auto anti A1 and anti H. No blood units were compatible for the patient. 17 A1, 3 A2 and 8 O group blood units were crossmatched and found incompatible at 37 degrees C and A2 and O at 25 degrees C--as the patient required surgery at hypothermia. Surgery was postponed. Antibody status was reviewed after 4 months. The thermal amplitude of auto anti H had changed by then but there was no change in auto anti A1. Surgery was done using A2 group blood.

Profile of transfusion transmissible infections and associated risk factors among blood donors of Kerala.

Blood transfusion is an important mode of transmission of infections to the recipient. The aim of the study was to assess the prevalence of transfusion transmissible infections and the possible risk factors among blood donors. During the study period (1994-99) donor samples were screened for HBsAg, HIV, HCV and Syphilis. The relevant donor history was examined to identify the risk factors leading to transfusion transmissible infections. The prevalence of infection was 3.1% among donors, with HBsAg constituting 1.3%, HCV 1.4%, HIV 0.2% and RPR 0.2%. In a classification based on occupation, class III donors (drivers, Businessmen & men in uniform) showed a significantly higher incidence of transfusion transmissible infections for HIV (0.38%) and Syphilis (0.36%). Health care workers constituted only a small fraction of the study; prevalence of infections was low among them. History of jaundice or hospitalization was not associated with higher incidence of seropositivity. Seropositivity for HIV is relatively low compared to similar studies conducted in other regions of the country. This finding is attributed to the pre donation counseling in donor selection. An important outcome of the study is that Class III donors form a high-risk group for transfusion transmissible infections.

Compatibility problems after intravenous immunoglobulin--a case report.

Serious incompatibility was noted in a patient diagnosed as acute Guillain Barre syndrome treated with intravenous immunoglobulin. Patient had positive direct and indirect antiglobulin test and the auto control was negative. There was no clinical signs of hemolysis. Patient's blood group was O D positive and cross matched several units of ABO compatible D positive and D negative blood. Only one unit was compatible. These findings suggest that the particular intravenous immunoglobulin contained a mixture of saline and immune antibodies having different specificity. As the number of patients getting treated with intravenous immunoglobulin is on the rise more and more compatibility problems should be anticipated and should be borne in mind during serological testing and evaluation.

Detection of high risk pregnancies with relation to ABO haemolytic disease of newborn.

IgM and IgG anti A and anti B antibody status of 100 antenatal O group mothers (who had non O group husbands) were studied. Of these, 3 mothers had an IgM anti A antibody levels ranging from 1:512 to 1:2048 and IgG ranging from 1:1204 to 1:2048, IgM anti B ranging from 1:128 to 1:512 and IgG anti B ranging from 1:256 to 1:512. All these mothers had A + ve children and all these children suffered from ABO haemolytic disease of newborn (HDN). A 4th mother had an IgM anti A titre of 1:64 and IgG anti A titre of 1:16. The titre of IgM anti B in this mother was 1:512 and that of IgG 1:1024. The child was A + ve and did not suffer from ABO haemolytic disease of newborn.

Morphological & ultrastructural changes of platelet concentrates stored in PVC bags.

To assess the effect of storage bags on platelets, we studied the morphological and ultrastructural changes of samples drawn from platelet concentrates (PC) prepared and stored in triple, poly vinyl chloride (PVC) bags, manufactured in India. Using the scanning electron microscopy, we demonstrate formation of long pseudopods, and interaction through these to form aggregates. When platelets were stored at 23 +/- 2 degrees C, morphological changes were severe compared to the deleterious effects when kept at 22 +/- 0.5 degrees C. Ultrastructural analysis also showed that maintenance of discoid shape and prevention of granule secretion could be improved by storing the platelets at 22 +/- 0.5 degrees C. Significant degree of platelet fragmentation took place when the storage temperature was high. The morphology score done for platelets stored at both 22 +/- 0.5 degrees C and 23 +/- 2 degrees C showed that preservation of discoid shape was better with the former.

Biochemical lesions of platelets stored as concentrates in PVC bags.

Acid-base status of platelet suspension during storage is a measure of the gas permeability of the bag material. To assess the efficacy of the bags available in our market to store platelets, we compared biochemical lesions of platelets stored in an Indian polyvinyl chloride (PVC) triple bag against a Japanese PVC bag standardized for 5 days platelet storage. Platelet concentrates prepared in both control and test PVC bags were stored for 72 h. Two ml samples were drawn 1 h after preparation, and then at 24 h intervals, for analysis. Our data show that the mean pH value in the test bags was maintained above 6.5. However, the CO2 tension was high and O2 tension was low. We also analyzed malondialdehyde (MDA) formation which is a measure of arachidonic acid metabolism, and seemed to be unaffected in stored platelets. Lactate dehydrogenase (LDH) was not released into the plasma excessively and hence significant platelet lysis was absent during storage. Hypotonic shock response (HSR) of platelets stored in both test and control bags was comparable, indicating the possibility of satisfactory post-transfusion recovery.

Para Bombay phenotype--a case report.

Bombay phenotype is peculiar in that red cells are not agglutinated by antisera A, B or H; while serum contains anti A, B and H. Existence of modifying genes at independent loci with variable expression of ABO genes is postulated. We report here a case of partial suppression where antigens could be detected by elution tests and unlike classical Bombay type, normal amount of appropriate blood group substances were present in saliva. This case of para Bombay phenotype was detected as a result of discrepancy in cell and serum group ng. This highlights the importance of both forward and reverse grouping in ABO testing.

Immune complex levels and plasmapheresis in Guillain-Barré syndrome.

Circulating IC levels were assayed serially in 12 G.B.S. patients treated with PE and an attempt was made to predict the outcome of treatment, from the levels of circulating IC. It was found that there was no significant correlation between the levels of circulating IC and the outcome of treatment with PE, in G.B.S. patients.