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Biomedical subjects

M Menon

Publications and source records attributed to M Menon.

At least 109 records · Page 6Linked to original sources
PubMed1987

Expression of FMC7 antigen and tartrate-resistant acid phosphatase isoenzyme in cases of B-lymphoproliferative diseases.

A panel of different B-cell malignancies representing various stages of B-cell differentiation were analyzed for the expression of an antigen labeled by the monoclonal antibody FMC7 and of tartrate-resistant acid phosphatase (TracP) activity. The FMC7 antigen and TracP were not found on early immature pre B-cell proliferations, appeared at early and intermediate B-cell stages, reached their peak of expression in terms of both incidence of positivity and staining intensity at the late B cell stage (as represented by hairy cell leukemia) and were lost at the B-cell/plasma cell transition. Although detected at similar stages of B-cell differentiation, FMC7 and TracP appear to be independently expressed and were not related to a particular Ig class. The simultaneous detection of FMC7 and TracP represents a distinguishing parameter for the identification of hairy cell leukemia.

Acid Phosphatase↗
PubMed1987

The effect of streptozotocin-induced diabetes on the neuroendocrine-male reproductive tract axis of the adult rat.

Studies in the streptozotocin rat model for diabetes mellitus suggest that sexual dysfunction in these animals may result from diabetes-induced alterations of the neuroendocrine-reproductive tract axis. Our investigation was performed to better define the effects of diabetes on the neuroendocrine sex accessory organ axis in the male rat. Rats were rendered diabetic, and were either left untreated or treated with insulin, testosterone or both. Diabetes resulted in decreased body and reproductive organ weights, as well as diminished sperm counts and motility and prostatic acid phosphatase. Seminal fructose was increased. A significant decrease in serum LH, FSH and testosterone was noted. Insulin treatment of the diabetic rats restored serum gonadotropins, reproductive organ weight, sperm counts and motility, and seminal fructose to control levels. Prostatic weight and prostatic acid phosphatase levels remained abnormal. Testosterone restored the above mentioned parameters to control levels, with the exception of LH. Treatment with insulin and testosterone had a synergistic effect on spermatogenesis. A GnRH stimulation test demonstrated that pituitaries of diabetic animals had a blunted response, with diminished LH and FSH secretion. In the diabetic animal, there are both pituitary and testicular abnormalities which may be responsible for reproductive dysfunction.

Animals↗
PubMed1987

Effect of cyclosporine A on male reproduction in rats.

We examined the effects of the immunosuppressive drug cyclosporine A on male reproduction in sexually mature rats. The drug was administered subcutaneously in 3 doses (10, 20 and 40 mg. per kg. daily) for 14 days. Cyclosporine A administration resulted in a dose-dependent decline in body and reproductive organ weights, histology of the testis showed definite degenerative changes, and sperm counts and motility decreased. Spermatozoa from treated rats retained the cytoplasmic droplet and they were decapitated. Consequently, sterility occurred in rats treated with high doses of cyclosporine A. A reduction in circulating testosterone and an increase in gonadotropins were noted. The possibility existed that the cyclosporine A-induced alterations in the male reproductive system were secondary to the hepatic or nephrotoxic effects of the drug. Therefore, we assessed liver and kidney function by assay of the serum levels of bilirubin, alkaline phosphatase, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase and creatinine. Except for an increase in bilirubin, none of the other liver function studies was altered, thereby eliminating hepatocellular damage as the etiology of impaired reproductive function in cyclosporine A-treated rats. We observed an increase in creatinine levels in animals treated with higher doses of cyclosporine A, consistent with mild renal failure. However, the fact that a decline in reproductive function was seen even in the group treated with 10 mg. per kg. cyclosporine A daily, which had normal serum creatinine levels, suggests that the alterations in male reproduction seen with this therapy are not entirely the result of nephrotoxicity.

Animals↗
PubMed1986

The uptake of oxalate by rat liver and kidney mitochondria.

Oxalate, a metabolic end product, forms calcium oxalate deposits in the tissues under a variety of pathological conditions. In order to determine whether oxalate is able to penetrate the mitochondrial matrix, the uptake of oxalate by rat liver and kidney cortical mitochondria was characterized. Mitochondria did not swell in an iso-osmotic medium of ammonium oxalate unless a small amount of phosphate was provided. This phosphate-induced swelling was prevented by N-ethylmaleimide. The uptake of [14C]oxalate by liver and kidney mitochondria followed first order kinetics and was inhibited by mersalyl an inhibitor of the phosphate and dicarboxylate carriers. Accumulation of [14C]oxalate at equilibrium was significantly higher by mitochondria energized with succinate than by rotenone-inhibited mitochondria due to higher matrix pH as determined by the [14C]5,5'-dimethyloxazolidine-2, 4-dione distribution ratio. The velocity of oxalate accumulation by mitochondria was temperature dependent. The activation energy was 81.5 and 86.5 J/mol for liver and kidney mitochondria, respectively. In both types of mitochondria, the rate of oxalate uptake was hyperbolic with respect to the concentration of oxalate. The apparent Km was 28.8 +/- 0.6 and 13.4 +/- 1.2 mM and the Vmax 87.1 +/- 1.1 and 66.1 +/- 3.1 nmol X mg-1 X min-1 at 12 degrees C for liver and kidney mitochondria, respectively. Phenylsuccinate exhibited mixed inhibition of the rate of oxalate uptake. Oxalate exhibited also a mixed inhibition of the uptake and oxidation of malate by mitochondria. The data obtained provide evidence that oxalate is transported across the mitochondrial membrane by a phosphate-linked, carrier-mediated system similar to or identical to the dicarboxylate transporter.

Animals↗
PubMed1986

Reactivity patterns of monoclonal antibodies positive on myelomonocytic leukemia cells as defined by esterase isoenzyme analysis.

The reactivity with monoclonal antibodies (MoAbs) specific for myelomonocytic cells and the expression of a particular esterase isoenzyme were analyzed in 159 cases of acute myeloid leukemias. The incidence of positivity of 16 MoAbs (MCS-2, MCS-1, OKM1, My-1, Leu-M1, Leu-M3, CA-2-38, MY4, MY7, MY8, MY9, VIM-D2, VIM-D5, Mo1, Mo2, 63D3) was studied using the indirect immunofluorescence technique. A carboxylic esterase isoenzyme which can be inhibited completely and selectively by sodium fluoride (NaF) was demonstrated by isoelectric focusing on horizontal polyacrylamide gels. This NaF-sensitive isoenzyme indicated the monocytic origin of the blast cells as it is specific for this cell lineage. Prior to the immunological-isoenzymatic analysis all cases were categorized into two subtypes according to morphological criteria of the FAB classification system: 147 cases of AML (FAB M1-3) and 12 cases of AMMoL/AMoL (FAB M4/5). However, 15 out of 147 cases of AML expressed the NaF-sensitive isoenzyme and were therefore assigned to the group AMMoL/AMoL. Likewise, 1 case, diagnosed morphologically as AMMoL, was negative for this marker isoenzyme and was assigned to the other leukemia subtype. The incidence of reactivity varied widely for the MoAbs tested regarding the overall results on all cases and the positivity of cases of either AML or AM-MoL/AMoL. The MoAbs were grouped into four classes depending on the pattern of reactivity with myeloblastic or monoblastic or both subtypes of acute myeloid leukemia. The MoAbs MCS-2, MY7, Leu-M1, and MY9 detected the vast majority of cases with either myelocytic or monocytic involvement (group-I: "pan-myelomonocytic" reactivity). The MoAbs MCS-1, OKM1, VIM-D5, and Mo1 showed a predominance in their staining pattern for monocytic variants, but were also positive on a substantial percentage of nonmonocytic cases (group-II: predominantly reactive with monocytic, but also myelocytic cases). The MoAbs Leu-M3, MY4, VIM-D2, Mo2, and MY8 reacted with the large majority of AMMoL/AMoL cases and with a small number of AML cases (group-III: monocyte-"specific" reactivity). The MoAbs of group-I are useful in differentiating acute lymphoid from acute myeloid leukemias. The MoAbs of group-III, and to a lower extent those of group-II, will be of considerable value in the subtyping of acute myeloid leukemias. The results show that accuracy of leukemia classification might not always be achieved by morphology alone, but that immunological and biochemical aspects should be included as well, and several MoAbs are very useful tools for classification and subtyping of acute myeloid leukemias.

Antibodies, Monoclonal↗
PubMed1986

Phenotyping of malignant hematopoietic cells. Analysis of 1200 cases of leukemia-lymphoma.

1255 cases of leukemia-lymphoma were tested between 1972 and 1984 by multiple marker analysis. Routine leukemia phenotyping was performed using standard morphological and cytochemical techniques in combination with clinical and histo-pathological information; the main emphasis was put on immunological surface marker analysis using erythrocyte rosette assays, TdT and a large panel of poly- and monoclonal antibody tests. The 1255 cases were divided into these major types and subtypes: 349 cases of ALL and related immature T- and Burkitt-lymphomas (cALL, pre B-ALL, B-ALL and Burkitt-lymphomas, T-ALL and immature, mostly leukemic T-lymphomas, Null-ALL), 454 cases of mature T- and B-cell malignancies (T-CLL, mycosis fungoides, Sezary-syndrome, T-lymphomas, B-CLL, hairy cell leukemia, multiple myeloma, B-lymphomas), 263 cases of acute myeloid leukemias (AML, AMMoL/AMoL), 182 cases of chronic myeloid leukemias (CML in chronic phase, CMoL, CML in blast crisis), 6 cases of erythroleukemia and 1 case of megakaryoblastic leukemia. A simplified classification scheme which has been used in our laboratories is presented. Phenotyping is of diagnostic, prognostic and therapeutic relevance, most evidently for patients with ALL. Routine leukemia phenotyping should be performed with highly standardized techniques and reagents and by combining information from several fields in the multiple marker analysis. New areas of leukemia research might become very useful for the routine procedure of phenotyping.

Adult↗
PubMed1986

Inhibition of gonadotropin-releasing hormone receptors in rat anterior pituitary monolayer cell cultures by danazol.

To study possible cellular antigonadotropic effects of danazol, monolayer cultures of anterior pituitary cells from immature female rats were treated with danazol. Measurements of luteinizing hormone release in response to 10(-8) mol/L gonadotropin-releasing hormone challenge and iodine 125-labeled gonadotropin-releasing hormone binding activity were done after exposure to increasing concentrations of danazol and for increasing lengths of time. It was found that luteinizing hormone secreted by pituitary cells in response to gonadotropin-releasing hormone was inhibited after danazol treatment in a dose- and time-dependent manner when compared to controls. Also, a 45% decrease in gonadotropin-releasing hormone receptor binding capacity was observed in pituitary cells cultured in the presence of increasing concentrations of danazol in the range of 10(-8) to 10(-4) mol/L when compared to controls. Furthermore, exposure to danazol for 25 to 96 hours caused a marked decrease in gonadotropin-releasing hormone binding activity (p less than 0.005). Under these experimental conditions danazol treatment decreased the pituitary receptors for gonadotropin-releasing hormone in a dose- and time-dependent manner. Scatchard analysis of saturation curves for the binding of gonadotropin-releasing hormone to cellular gonadotropin-releasing hormone receptors indicated that the observed decrease in gonadotropin-releasing hormone binding in the danazol-treated group was due to a change in the number of gonadotropin-releasing hormone binding sites rather than a change in the affinity. It is therefore concluded that the antigonadotropic activity of danazol appears to be related to a decrease in gonadotropin-releasing hormone receptors in the pituitary.

Animals↗
PubMed1986

Reactivity pattern of 'myeloid monoclonal antibodies' with emphasis on MCS-2.

The reactivity pattern of the murine monoclonal antibody (MoAb) MCS-2 was tested on a panel of 724 cases of leukemia-lymphoma. MCS-2 was positive in 178/185 (96%) cases of AML (FAB M1-3), 10/10 cases of AMMol/AMoL (FAB M4/5), 42/45 (93%) cases of CML, 1/1 case of CMoL, 37/38 (97%) cases of CML-myeloid blast crisis, 0/9 cases of CML-lymphoid blast crisis. No positive staining was seen in 238 cases of T-CLL, mycosis fungoides, Sèzary-syndrome, B-CLL, hairy cell leukemia, multiple myeloma and T- and B-lymphoma nor in 32 cases of B-ALL, Burkitt-lymphoma, Null-ALL and immature T-lymphoma. A positive expression was found in 8/110 cases of cALL, 1/6 cases of pre B-ALL and 1/35 cases of T-ALL. Fifteen other MoAbs (MCS-1, OKM1, My-1, Leu-M1, Leu-M3, CA-2-38, MY4, MY7, MY8, MY9, VIM-D2, VIM-D5, Mol, Mo2, 63D3) which are associated with the myelomonocytic cell lineages were tested by indirect immunofluorescence on 60 or more patients (62-149 cases). A wide variability in the frequency of positivity was seen for the panel of cases studied and for the blast cell populations per individual samples: 21-96% of the AML cases (FAB M1-3) and 31-100% of the AMMoL/AMoL cases (FAB M4/5) were positive for the various MoAbs. None of the analysed MoAbs stained only myelocytic or only monocytic leukemias, but a certain degree of preference for the monocytic variants was noted for Leu-M3, CA-2-38, MY4, VIM-D2, Mo2 and 63D3. The detection of MCS-2 on immature ALL blast cells might indicate a coexpression of lymphoid and myeloid markers on very immature cells, or an abnormal gene expression by malignant cells, or the identification of a so far undetected subclass of acute leukemias.

Adult↗
PubMed1986

Heterogeneity of marker expression in B-cell leukemias and its diagnostic significance.

Lymphoproliferative disorders of B-cell origin are identified by surface immunoglobulin markers. Clinically, these include several types of leukemias and lymphomas. We have attempted to further characterize B-cell leukemias immunologically using monoclonal antibodies Leu-1 and FMC-7. While cases of classical B-CLL have been shown to react with Leu-1 monoclonal, most other B-cell leukemias often do not react with Leu-1. Our results show that use of an additional monoclonal FMC-7 does not contribute towards diagnostic reliability.

Antibodies, Monoclonal↗
PubMed1986

Binding of oxalate to mitochondrial inner membranes of rat and human kidney.

Oxalate bound specifically to homogenates of rat kidney and liver but not to homogenates prepared from heart, lung, skeletal muscle, spleen, stomach, small or large intestine. In the renal cortex, binding was localized to the inner mitochondrial membrane where it was enriched fourfold when compared to homogenate. Binding of the oxalate reached equilibrium in two minutes at 23C. Analysis of the binding sites by Scatchard plot indicated that the maximum binding capacity was 49 pmol./mg. protein and the apparent dissociation constant (Kd) was 43 nM. The IC50 of oxalate was 0.25 microM. Among the inhibitors studied the IC50 was in the following order: oxalate less than oxamate less than parabanate less than glyoxalate less than oxaloacetate less than malate less than citrate = glycollate. Heat and treatment with lubrol abolished the binding completely. Binding was not enhanced by the presence of calcium in the incubation medium; neither was it inhibited by the presence of calcium together with its transport inhibitors. A binding substance with some characteristics similar to the rat mitochondrial binding factor was also found in the human renal cortex.

Animals↗