Epidemiological studies of blood groups in the district of Bankura with special reference to tribals

Distribution of ABO blood groups was studied in 4301 subjects, both tribals and non-tribals of the district of Bankura in West Bengal. It was observed that group 'O' blood was found in most cases and group 'AB' was seen in least number of cases. It was also found that there was no significant difference in distribution of blood groups between the tribals and non-tribals.

Fallacies of the fine needle aspiration cytology of surgical lesions of liver

Seventy-six cases of surgical hepatomegaly were subjected to fine needle aspiration cytology (FNAC) for initial diagnosis. Primary malignancies, as suspected clinically with adjunction of other investigative procedures, were 29 cases of whom 25 were confirmed by biopsy or therapy. Secondary deposits in liver were 27 of whom 15 were confirmed by therapy. Inflammatory lesions were 9 of whom 6 were confirmed by therapeutic response with specific therapy. Benign lesions were 10 of whom 5 were confirmed by surgery. Diagnosis of malignancies of liver is rather easier than that of benign lesions like hydatid cysts of liver which were Casoni's test negative; and hepatocellular adenoma, as the aspirate in the former is clear fluid and that of the latter is only normal looking liver cells. Thus, in respect of benign lesions of liver, FNAC diagnosis may be clinched after due consideration to the clinical findings, radiological and ultrasonographic findings and ultimately confirmed by exploration. Thus the fallacy lies in aspiration of normal looking liver cells whereby the histology may prove it to be hepatocellular adenoma, well differentiated hepatocellular carcinoma and secondary deposits where the exact site has not been hit. Ultrasonogram (USG) guidance helps in these cases where the same facility is available. This fallacy can again be avoided, where USG guidance is not available, by imparting due importance to clinical findings, USG findings and also by repeat smear.

Axons arrest the migration of Schwann cell precursors

The neural crest gives rise to a variety of cell types including Schwann cells of the peripheral nervous system. Schwann cell precursors begin to differentiate early and migrate along specific pathways in the embryo before associating with nerve trunks. To determine whether motor axons direct the migration of Schwann cell precursors along specific pathways, we tested the effect of ablating the ventral half of the neural tube, which contains motor neuron cell bodies. The ventral neural tube was removed unilaterally from lumbar regions of chicken embryos at stage 17, when neural crest cells are just beginning to migrate and before motor axons have extended out of the neural tube. At several stages after ventral tube ablation, sections of the lumbar region of these embryos were stained with anti-acetylated tubulin to label developing axons, HNK-1 to label migrating neural crest cells and 1E8 to label Schwann cell precursors. In many embryos the ablation of motor neurons was incomplete. The staining patterns in these embryos support the idea that some Schwann cells are derived from the neural tube. In embryos with complete motor neuron ablation, at stage 18, HNK-1-positive neural crest cells had migrated to normal locations in both control and ablated sides of the embryo, suggesting that motor axons or the ventral neural tube are not required for proper migration of neural crest cells. However, by stage 19, cells that were positive for HNK-1 or 1E8 were no longer seen in the region of the ventral root, nor ventral to the ventral root region. Because Schwann cell precursors require neural-derived factors for their survival in vitro, we tested whether neural crest cells that migrate to the region of the ventral root in ventral neural tube-ablated embryos then die. Nile Blue staining for dead and dying cells in ventral neural tube-ablated embryos provided no evidence for cell death at stage 18. These results suggest that motor axons arrest the migration of Schwann cell precursors during neural crest migration.

Specificity of ATP for the initiation of flagellar motility of hamster sperm

Hamster sperm collected from the cauda epididymis were washed and the pellet diluted in a medium containing Triton x 100 (Sigma, Saint Louis, MO, USA) to dissolve the cell membrane and then reactivated with various concentrations of ATP (0-3 mM). Spermatozoal axonemes were initially immotile but the maximal percentage motility was obtained almost immediately following addition of 1 mM ATP. A stepwise increase in the concentration of ATP caused a 5-min delay in development of maximal reactivation and a change in the beating pattern as indicated by a decrease in the percentage of reactivating sperm. Under the same experimental condition GPT, UTP, CTP, and AMP failed to initiate the axonemal motility. In demembranated sperm reactivated by ADP, however, the beat frequency was lower compared with that reactivated by ATP. Pretreatment of the sperm with the mitochondrial phosphorylation blockers oligomycin and 2'4'-DNP (dinitrophenol) failed to inhibit the axonemal movement, although the presence of the dynein ATPase inhibitor, vanadate, was able to inhibit the reactivation. These results suggest that the exogenous ATP, but not the mitochondrial ATP, is responsible for axonemal motility.

A study of colchicine tubulin complex by donor quenching of fluorescence energy transfer

The utility of collisional quenching of energy donors in fluorescence energy transfer is described. In multi-donor single acceptor systems, which contain different classes of donors (as distinguished by their accessibility towards a collisional quencher), donor quenching may be used to assess the fraction of energy transfer from each class of donor. The tubulin-colchicine complex was used as a donor-acceptor system to show that two inaccessible tryptophans are at or near the colchicine binding site.

Clonal chromosome abnormalities in human breast carcinomas. I. Twenty-eight cases with primary disease

Cytogenetic analysis was performed on a selected series of short-term cultures of primary breast carcinomas from 28 patients. All patients had histopathologically confirmed malignancies, with the majority (25/28 cases) demonstrating infiltrating ductal carcinoma. All 28 cases evidenced clonal chromosome abnormalities, with 10/28 displaying only numeric aberrations, whereas 18/28 displayed clonal structural alterations. In near-diploid tumors the most common numeric changes were -17 and -19. However, trisomy 7 was the only numeric change in two near-diploid tumors. Structural chromosome alterations were primarily isochromosomes, apparent terminal deletions, and unbalanced non-reciprocal translocations. Chromosomes I (10/18-56%) and 6 (8/18-44%) were most frequently altered in this series. Breakpoints of clonal structural abnormalities were shown to cluster to several chromosome segments, including 1p22-q11, 3p11, 6p11-13, 7p11-q11, 8p11-q11, and 19q13. Analysis of the gain or loss of specific chromosome segments revealed that the most consistent tendency was over-representation of 1q, 3q, and 6p.

Neuron-Schwann cell signals are conserved across species: purification and characterization of embryonic chicken Schwann cells

A monoclonal antibody, 1E8, which recognizes the peripheral myelin protein, P0, specific for chicken Schwann cells and their precursors (Bhattacharyya et al., Neuron 7:831-844, 1991), was used to immunoselect Schwann cells from embryonic day 14 (E14) chicken sciatic nerve. When cultured, these immunoselected cells displayed properties characteristic of perinatal rodent Schwann cells, including S100-immunoreactivity and O4 antigen-immunoreactivity. In addition, the purified chicken Schwann cells divided slowly when cultured alone, but when co-cultured with chicken or rat sensory neurons, they bound to axons and proliferated. Proliferation was also stimulated by the addition of bovine brain membrane extracts or chicken brain membranes. The 1E8 monoclonal antibody was also used to test the effect of axonal contact on P0 expression. Chicken Schwann cells purified using the 1E8 monoclonal antibody gradually lost P0 when cultured alone. These cells remained 1E8-negative even after prolonged co-culture with embryonic rat dorsal root ganglion neurons or chicken sensory ganglia. These results demonstrate that chicken Schwann cells behave like rodent Schwann cells in their expression of specific antigens, interactions with axons, and regulation of P0 expression. In addition, chicken Schwann cells respond to neuronal signals from the rat and cow, illustrating the cross-species conservation of these signals.

Adolescent pregnancy in Grenada

A retrospective review of adolescent deliveries (maternal age range: 12-19 years) at the maternity unit of the main General Hospital, Grenada, was undertaken for the years 1987 and 1988 using the delivery room register and hospital medical records. These mothers were compared with women who delivered during the same period but were aged between 20 and 30 years. Of the 3203 deliveries which occurred during the study period, 613 (20%) involved adolescents, giving a prevalence rate of one in five pregnancies. chi 2 and Fisher's exact test analyses revealed that pregnancies occurring in younger adolescents (age less than 16 years, n = 58) carried an increased risk of preterm labour, operative delivery, prematurity, small-for gestational age infants, asphyxia and perinatal mortality when compared with the 'optimum reproductive age group'. Older adolescents (16-19 years, n = 555) had a higher risk of pregnancy induced hypertension but otherwise compared well with the optimal reproductive age group. Adolescent pregnancy is very prevalent in Grenada and the reproductive outcome for young adolescents < 16 years of age is relatively poor.

Kinking of RNA helices by bulged bases, and the structure of the human immunodeficiency virus transactivator response element

We have used gel electrophoresis to show that the pyrimidine bulge of the HIV-1 TAR sequence causes a local bending of the helical axis. The TAR bulge caused a retardation in electrophoretic mobility in polyacrylamide gels. When this was placed adjacent to an additional bulged sequence in a linear RNA fragment, the mobility of the molecule varied sinusoidally with the spacing between the two bulges. Electrophoretic mobilities suggested that the TAR sequence context of the pyrimidine bulge causes a greater degree of axial kinking than in an equivalent randomly chosen sequence. Experiments in which an A5 bulge was progressively opposed by adenine bases inserted in the opposite strand showed that even a single opposed adenine markedly reduced electrophoretic mobility, i.e. axial bending, and two adenine bases reduced the mobility virtually to that of a normal duplex. We suggest that the pronounced kinking resulting from an unopposed bulge provides a particularly recognizable feature in RNA, and that this is the basis of the interaction between the HIV Tat protein and the TAR sequence.

S100 is present in developing chicken neurons and Schwann cells and promotes motor neuron survival in vivo

We used polyclonal antisera recognizing S100, a small acidic protein highly enriched in nervous tissue, to stain sections of embryonic chicken lumbosacral spinal cord and hindlimb. S100 immunoreactivity was detected in developing sensory neurons of the dorsal root ganglia (DRG) and motor neurons of the ventral spinal cord as early as embryonic day (E) 5, and staining persisted through hatching. In contrast, expression of S100 first became apparent in Schwann cells at E13, just before myelination, and was not detected in developing skin or muscle. Since S100 beta was present in motor and sensory neurons and is known to promote neuronal survival and neurite extension in vitro (Winningham-Major, Staecker, Barger, Coats, and Van Eldik, 1989), we tested the ability of S100 to promote neuron survival in an in ovo survival assay. Addition of S100 to chick embryos in ovo during the period of naturally occurring motor neuron cell death resulted in a significant increase in motor neuron survival, but had no effect on the in vivo survival of sensory neurons in the DRG. The findings that S100 is present in spinal motor neurons and that the addition of S100 enhances the survival of these cells in vivo are consistent with the possibility that S100 may act as a naturally occurring neuron survival factor during development.

Albumin is required for the guinea pig sperm capacitation but is not essential for acrosome reaction and fusion with eggs

The importance of serum albumin in supporting guinea pig sperm capacitation, acrosome reaction, and fusion with eggs in vitro was studied by incubating the spermatozoa in albumin-free medium containing different synthetic polymers. Serum albumin was found to be an obligatory component in the incubating medium for the capacitation of guinea pig spermatozoa. Albumin in the medium is not essential for the acrosome reaction and fusion with the eggs, but these phenomena take place most efficiently in presence of albumin.

P0 is an early marker of the Schwann cell lineage in chickens

We have generated a monoclonal antibody, termed 1E8, that is specific for myelinating and nonmyelinating Schwann cells in mature chickens. 1E8 first stains cells at the edge of the neural crest; later, cells located between the neural tube and somites and in the sclerotome are immunopositive. Double labeling with HNK-1 indicates that these 1E8-positive cells represent a subset of neural crest cells in the ventral migratory pathways. 1E8-positive cells are later associated with the dorsal and ventral roots and with extending nerve trunks. In Western blots, 1E8 reacts with proteins comigrating with P0. Immunodepletion experiments establish that all P0 molecules carry the 1E8 determinant. The developmental distribution of P0, as determined by 1E8 immunoreactivity, differs from that reported for P0 in mammals and suggests that, in chicken, P0 is an early marker for the Schwann cell lineage.

Model for the interaction of DNA junctions and resolving enzymes

Four-way DNA junctions are thought to be important intermediates in a number of recombination processes. Resolution of these junctions occurs by cleavage of two strands of DNA to generate two duplex molecules. The interaction between DNA junctions and resolving enzymes appears to be largely structure-specific, reflecting a molecular recognition on a significant scale. We propose a working model for this interaction that takes account of the present state of knowledge of the structure of the DNA junction, and the substrate requirements of the enzymes. We note that three different enzymes introduce cleavages at phosphodiester bonds that are presented on one side of the molecule, suggesting that the enzymes selectively interact with this face of the junction. By forcing a junction of constant sequence to adopt one or other of the two possible antiparallel isomers, we show that the junction is cleaved in such a way as to suggest a constant mode of interaction with the protein that is dependent on structure rather than sequence. We propose that the feature that is recognized is a mutual inclination of two DNA helices at approximately 120 degrees. We show that a number of DNA substrates that contain similar inclined helices, such as a three-way junction, bulged duplexes and a duplex that is curved because of repeated runs of oligoadenine sequences, are each cleaved by phage T4 endonuclease VII. This mode of DNA-protein interaction could be significant in either recombination or DNA repair processes.

A fluorescence spectroscopic study of glutaminyl-tRNA synthetase from Escherichia coli and its implications for the enzyme mechanism

Interaction between Escherichia coli glutaminyl-tRNA synthetase (GlnRS) and its substrates have been studied by fluorescence quenching. In the absence of other substrates, glutamine, tRNA(Gln) and ATP bind with dissociation constants of 460, 0.22 and 180 microM, respectively. The presence of other substrates has either no effect or, at best a weak effect, on binding of ligands. Attempts to isolate enzyme-bound aminoacyl adenylate did not succeed. Binding of the phosphodiester, 5'-(methyl)adenosine monophosphate (MeAMP), to GlnRS was studied by fluorescence quenching and radioactive-ligand binding. tRNA also only has a weak effect on phosphodiester binding. Selectively pyrene-labeled GlnRS was used to obtain shape and size information for free GlnRS. A comparison with the GlnRS shape in the GlnRS/tRNA(Gln) crystal structure indicates that no major change in shape and size occurs upon tRNA(Gln) binding to GlnRS. 5,5'-Bis(8-anilino-1-naphthalene sulfonate) (bis-ANS), a non-covalent fluorescent probe, was also used to probe for conformational changes in GlnRS. This probe also indicated that no major conformational change occurs upon tRNA(Gln) binding. We conclude that lack of tRNA-independent pyrophosphate-exchange activity in this enzyme is not a result of either lack of glutamine or ATP binding in the absence of tRNA, or formation of aminoacyl adenylate and slow release of pyrophosphate. A conformational change is implied upon tRNA binding, which promotes pyrophosphate exchange. Fluorescence studies indicate that this conformational change must be limited and local in nature.

Eosinophil cationic protein's role in human hepatic allograft rejection

Although it is known that eosinophils consistently infiltrate rejecting human liver allografts, their function is unknown. Infiltrating eosinophils can release a cytotoxic substance, eosinophil cationic protein. Furthermore, eosinophil cationic protein may be identified in biopsy specimens using immunoperoxidase staining of an eosinophil cationic protein-specific monoclonal antibody. To study a possible effector role of eosinophils in rejecting liver allografts, 38 serial allograft biopsy specimens from 12 patients with acute rejection, 54 biopsy specimens from 11 patients with allograft dysfunction caused by other causes and 22 biopsy specimens from 8 patients without allograft dysfunction were stained for extracellular eosinophil cationic protein. In addition, the absolute blood eosinophil counts and the portal tract eosinophil percent of the total number of portal tract inflammatory cells were tabulated in these patients until 30 days after transplantation. The blood absolute eosinophil count, portal tract eosinophil percent and incidence of positive extracellular eosinophil cationic protein staining were significantly increased in patients with rejection compared with patients with dysfunction from other causes (p less than 0.05 to 0.005, t test). Furthermore, each of these parameters predicted rejection with excellent sensitivity (75% to 92%) and specificity (91% to 100%). Of patients with rejection, 59% had significant elevation of all three parameters before or during rejection, and 92% had at least two parameters elevated. Conversely, of the patients with dysfunction from other causes, 0% had elevations of any parameter. The recognized cytotoxic properties of eosinophil cationic protein and its almost exclusive presence, along with eosinophils in the blood and allograft biopsy specimens of patients during acute rejection, support the role of the eosinophil as an effector cell in tissue injury during acute liver allograft rejection.

Morphometric inflammatory cell analysis of human liver allograft biopsies

To quantitate the inflammatory cell response within the portal tracts of liver allografts during acute rejection, we retrospectively and in a blinded fashion reviewed 431 biweekly, protocol, core allograft biopsies in 58 consecutive adult recipients. Following the determination of the cross-sectional area of each portal tract, the number of eosinophils, neutrophils, and lymphocytes therein was tabulated. The average number, percentage, and density of each type of portal inflammatory cell were calculated for each biopsy. Each biopsy was prospectively and independently classified as either associated (REJ+) or not associated (REJ-) with acute rejection. Acute rejection consisted of simultaneous allograft dysfunction and qualitative pathologic findings of acute rejection. Biopsies obtained during periods of normal allograft function or during episodes of dysfunction due to other causes were classified as not associated with rejection (REJ-). Ninety biopsies were classified as associated with acute rejection (REJ+) while 241 biopsies were classified as not associated with acute rejection (REJ-). In general, the average portal-tract number, percentage, and density of all inflammatory cells were significantly increased in biopsies associated with acute rejection. In contrast, only the portal-tract eosinophil values were consistently predictive of acute rejection following receiver-operating characteristic curve analysis (sensitivity = 82-86%, specificity = 91-92%). This quantitative method of allograft assessment appears to improve the objectivity of the serial biopsy protocol. By using this method, we found the eosinophil's appearance within the portal tracts to be a dependable indicator of acute rejection.