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Biomedical subjects

N C Jain

Publications and source records attributed to N C Jain.

At least 37 records · Page 2Linked to original sources
PubMed1989

Ultrastructural analysis of platelets and megakaryocytes from a dog with probable essential thrombocythemia.

Blood platelets and bone marrow megakaryocytes from a dog with essential thrombocythemia were analyzed by transmission electron microscopy and compared with those of control dogs. Platelets varied in size and shape and contained enlarged and dilated open canalicular systems. Megakaryocytes were dysmorphic and had evidence of abnormal maturation, with large numbers of megakaryoblasts containing alpha granules and poorly organized and reduplicated demarcation membranes. The fewer, more mature megakaryocytes lacked normal cytoplasmic organization. Most notable was the absence of well-demarcated "platelet fields," due to the excessive and disorderly array of demarcation membranes.

Animals↗
PubMed1989

Mechanisms of platelet destruction in immune-mediated thrombocytopenia: in vitro studies with canine platelets exposed to heterologous and isologous antiplatelet antibodies.

Normal canine platelets coated with heterologous or isologous antiplatelet antibody were interacted with viable canine neutrophils in vitro. Platelet phagocytosis was assessed by detecting nitroblue tetrazolium (NBT) reduction, measuring uptake of opsonised 51Cr-labelled platelets, and electron microscopy. The NBT reduction and uptake of 51Cr-labelled opsonised platelets were markedly increased. Electron microscopy revealed phagocytosis of antibody-coated platelets and their degradation intracellularly. Exposure of canine platelets to rabbit anti-canine platelet antibody in vitro produced morphological changes in platelets and caused serotonin release. Serotonin was not released in the absence of antiplatelet antibody or in the presence of normal rabbit gamma-globulin. Morphological changes in the platelets included disappearance of alpha and dense granules and exaggeration of the open canalicular system. These observations indicate that circulating platelets may be vulnerable to an antiplatelet antibody and that antibody-mediated phagocytosis of platelets is an important mechanism in the pathogenesis of immune-mediated thrombocytopenia.

Animals↗
PubMed1989

Effects of glycolytic and cytoskeletal inhibitors on phagocytic and nitroblue tetrazolium reductive activities of bovine neutrophils.

Phagocytic and oxidative metabolic activities of bovine blood neutrophils were determined in the presence of glycolytic (NaF) and cytoskeletal (colchicine, cytochalasin B, and prostaglandin E1) inhibitors. Phagocytosis and post-phagocytic oxidative metabolic activity, measured by nitroblue tetrazolium reduction, were determined using zymosan, Escherichia coli, Staphylococcus aureus, or Streptococcus agalactiae. Sodium fluoride (1.25 microM to 1.25 mM concentrations) did not significantly (P greater than 0.05) inhibit phagocytosis of S aureus and Str agalactiae, whereas phagocytosis of zymosan and E coli was significantly (P less than 0.05) inhibited only at 1.25 mM concentration. Colchicine at 1.25 nM to 1.25 microM concentrations significantly inhibited phagocytosis of zymosan and E coli, but not of S aureus and Str agalactiae. Cytochalasin B at 1.25 nM to 1.25 microM concentrations significantly inhibited phagocytosis of zymosan and all 3 bacteria, whereas prostaglandin E1 was noninhibitory at similar concentrations. Nitroblue tetrazolium reduction, in general, was not significantly affected by NaF and cytoskeletal inhibitors.

Alprostadil↗
PubMed1989

Haematological changes in buffalo calves inoculated with Escherichia coli endotoxin and corticosteroids.

Haematological studies were conducted on 10 clinically normal water buffalo calves to determine leucocytic responses to Escherichia coli endotoxin, prednisolone and dexamethasone. Intravenous injection of 10 micrograms endotoxin induced minimal decreases in leucocyte numbers, whereas 20, 50 and 100 micrograms produced a marked leucopenia within one hour. Moderate to marked leucopenia, neutropenia and lymphopenia persisted for three to 14 hours. Significant rebound neutrophilia was evident at six to eight hours after inoculation in calves given only 10 and 20 micrograms. Intramuscular injection of prednisolone (100 mg) and dexamethasone (5 mg) produced increases in total leucocyte counts and neutrophil numbers within two hours. Moderate to marked leucocytosis and neutrophilia persisted for eight to 24 hours. Lymphocyte response was unlike that in other species in that lymphopenia was not a consistent feature of the corticosteroid response. A transient monocytosis was seen following administration of prednisolone but not of dexamethasone, while eosinopenia and basopenia developed in both cases. In conclusion, endotoxin and corticosteroid induced changes in total and differential leucocyte counts in water buffalo were largely similar to those seen in cattle.

Animals↗
PubMed1989

Phagocytic and nitroblue tetrazolium reductive properties of mature and immature neutrophils and eosinophils from blood and bone marrow from cows.

Functional capabilities of morphologically mature (segmented) and immature granulocytes (neutrophils and eosinophils) from bone marrow from cows were studied and compared with similar activities of segmented granulocytes from blood. Phagocytosis of Escherichia coli and postphagocytic oxidative metabolic stimulation, measured by nitroblue tetrazolium (NBT) reduction, were evaluated simultaneously. Phagocytosis was observed readily in segmented neutrophils, neutrophilic bands, and metamyelocytes and rarely in myelocytes. Phagocytosis was not seen in promyelocytes and myeloblasts. Neutrophilic bands and metamyelocytes were phagocytically less active than were segmented neutrophils. Washed segmented bone marrow neutrophils possessed phagocytic activity similar to that of blood neutrophils, whereas the activity of unwashed segmented bone marrow neutrophils was markedly less than that of blood neutrophils. Reduction of NBT was observed only in blood segmented neutrophils and bone marrow segmented neutrophils; the magnitude of NBT reduction was significantly (P = less than 0.005) less in bone marrow neutrophils than in blood neutrophils. Eosinophils were phagocytically less competent than were neutrophils. The NBT reduction was observed only in eosinophils from blood, but not in eosinophils from bone marrow.

Animals↗
PubMed1988

Nonspecific esterase of acute promyelocytic leukemia (M3).

Leukemic cells of 43 patients with acute promyelocytic leukemia (M3) were investigated morphologically and cytochemically to determine the percentage of aberrant enzymes and whether or not the presence impacts on the clinical outcome. Twelve patients (27.9%) showed alpha-naphthyl acetate esterase (ANAE) activity in their leukemic cells, and two of these cases revealed remarkably low myeloperoxidase (MPO) positivity, a pattern seen in monocytic precursors. However, further cytochemical evidence for this monocytic feature, the inhibition of naphthol AS-D acetate esterase (NASDA) activity with sodium fluoride (NASDA-F), was found in only five of these nine patients. In 31 cases (72.1%), there was minimal ANAE activity. Of interest, two of these were devoid of naphthol AS-D chloroacetate esterase (CAE), which is prominently displayed in neutrophilic granulocytes, even though these leukemic cells were 100% intensely positive for MPO activity. Between the two groups with and without ANAE activity, there were no remarkable differences in the distribution of sex and age, hematological findings, and rates of complete response. Our study has confirmed the cytochemical heterogeneity of M3 with no obvious relationship between this heterogeneity and early therapeutic outcome.

Adolescent↗
PubMed1988

Bizarre lymphoid cells in serous effusion of a dog with mediastinal lymphoma.

An 8-year-old collie dog was examined because of dyspnoea. Thoracocentesis revealed a modified transudate containing a predominance of large (10 to 15 microns diameter) unusual-appearing mononuclear cells showing cloverleaf-shaped nuclei. These cells were categorized as lymphoid in origin on the basis of ultrastructural and cytochemical methods. Subsequent necropsy examination revealed lymphoma, localized primarily to the cranial mediastinum, but also infiltrating tissues surrounding the thyroid, parathyroid and adrenal glands.

Animals↗
PubMed1988

Quantitative platelet disorders.

Thrombocytopenia may be caused by abnormal platelet production, accelerated removal owing to immunologic or nonimmunologic reasons, or sequestration of platelets in the spleen. Bleeding associated with thrombocytopenia usually presents as petechial or ecchymotic hemorrhages or epistaxis. Immunologic and nonimmunologic cases of thrombocytopenia may be diagnosed with routine hematology, bone marrow cytology, and platelet specific tests. Thrombocythemia may also be associated with platelet functional abnormalities, contrasting the normal platelet function noted in reactive thrombocytosis.

Animals↗
PubMed1988

Combined phagocytosis-nitroblue tetrazolium reduction test in bovine neutrophils.

An assay was developed for the simultaneous evaluation of phagocytosis and oxidative metabolism of bovine blood neutrophils. Phagocytosis was evaluated by using opsonized zymosan, and oxidative metabolism was evaluated by nitroblue tetrazolium (NBT) reduction. Normal bovine neutrophils exhibited moderate variation in ability to phagocytize zymosan, but little variation in ability to reduce NBT. The subcellular location of NBT reduction to formazan was determined by electron microscopy. Electron dense formazan precipitate was observed along the inner membrane of phagosomes enclosing zymosan particles and radiating from the membrane toward the center of the phagosome.

Journal Article↗
PubMed1988

Phagocytic and nitroblue tetrazolium reductive properties of bovine neutrophils for mammary pathogens.

A comparative evaluation of in vitro phagocytic and metabolic activities of freshly isolated bovine blood neutrophils from 26 cows was performed. Degrees of phagocytosis and nitroblue tetrazolium reduction by neutrophils were measured using zymosan, Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis, Salmonella sp., and Brucella abortus opsonized with fresh bovine serum. Percent phagocytosis and nitroblue tetrazolium reduction by the neutrophils were determined by microscopic evaluation of stained coverslip smears. Individual variation among cows was found in parameters measured, but age was not a contributing factor. Phagocytosis was high (73 to 81%) for E. coli, Salmonella sp., Strep. agalactiae, and zymosan; intermediate (64%) for Staph. aureus; and low (24 to 40%) for M. bovis and B. abortus. Nitroblue tetrazolium reduction was distinctly lower than zymosan (74%) for all microorganisms. Similar percentages (32 to 41%) of nitroblue tetrazolium reduction were observed for E. coli, Staph. aureus, Strep. agalactiae, and M. bovis; intermediate (28%) was obtained for Salmonella sp. and lowest (11%) for B. abortus.

Animals↗
PubMed1988

Phagocytic and postphagocytic activities of bovine neutrophils for pure and mixed bacterial cultures.

A comparative study of phagocytosis and postphagocytic oxidative metabolic activity of bovine blood neutrophils incubated with pure and mixed cultures of Escherichia coli, Staphylococcus aureus, and Streptococcus agalactiae was preformed. Most neutrophils when incubated with mixed cultures showed preferential phagocytosis for one species and a smaller number phagocytized both species of microorganisms. Percent phagocytosis for E. coli in pure culture was similar to that of Strep. agalactiae in pure culture and higher than that for Staph. aureus in pure culture. Neutrophils incubated with mixed cultures of E. coli and Staph. aureus or E. coli and Strep. agalactiae showed greater than expected phagocytosis of each microorganisms alone and reduced phagocytosis of both microorganisms together. Postphagocytic oxidative metabolic activity of neutrophils, measured by percent nitroblue tetrazolium reduction, did not differ following phagocytosis of these three microorganisms in pure cultures. In comparison, a synergistic effect on nitroblue tetrazolium reductive activity was seen in mixed cultures as evidenced by higher percent nitroblue tetrazolium reduction following phagocytosis of both E. coli and Staph. aureus or E. coli and Strep. agalactiae. These observations indicate that the phagocytic and metabolic activities of neutrophils for bacteria in mixed cultures may not be identical to those in pure cultures.

Animals↗
PubMed1987

Scanning electron microscope study of platelet release by canine megakaryocytes in vitro.

Megakaryocytes were isolated from bone marrow from healthy dogs, using a combination of density-gradient centrifugation and polysucrose-velocity sedimentation techniques. The 2-step separation technique resulted in a preparation comprising 30% to 35% megakaryocytes of total nucleated cells. Accessibility to large numbers of viable canine megakaryocytes allowed investigation of platelet release by these cells in short-term cultures. Megakaryocytes were observed to form long cytoplasmic processes that gradually developed segmental constrictions and subsequently fragmented into platelet-sized pieces. Some platelet-sized cytoplasmic pieces of megakaryocytes presumably underwent discoid transformation.

Animals↗
PubMed1987

Circulating proplatelets: isolation and quantitation in healthy rats and in rats with induced acute blood loss.

A technique to isolate megakaryocyte proplatelet processes from blood of rats' hearts, using colloidal silica coated with polyvinylpyrrolidone density gradient, was developed. The proplatelet concentration in blood from right ventricles was significantly higher (P less than 0.001) than that in blood from left ventricles in healthy rats, as well as in rats with induced acute blood loss. The proplatelet concentration of blood from the heart, 24 hours after acute blood loss was induced was significantly (P less than 0.001) increased, indicating that platelet production was accelerated. The demonstration of proplatelets entering the pulmonary circulation indicates platelet release via proplatelet formation. Seemingly, proplatelets are fragmented in the lungs at predesignated locations along the proplatelet process.

Acetylcholinesterase↗