Biomedical subjects

A K Nandedkar

Publications and source records attributed to A K Nandedkar.

18 recordsLinked to original sources

PubMed1990

Interaction of osteogenin, a heparin binding bone morphogenetic protein, with type IV collagen.

Osteogenin, an extracellular matrix component of bone, is a heparin binding differentiation factor that initiates endochondral bone formation in rats when implanted subcutaneously with an insoluble collagenous matrix. We have examined the interaction of osteogenin with various extracellular matrix components including basement membranes. Osteogenin, purified from bovine bone, binds avidly to type IV collagen and to a lesser extent to both type I and IX collagens. Osteogenin binds equally well to both native and denatured type IV collagen. Both alpha 1 and alpha 2 chains of type IV collagen are recognized by osteogenin. Osteogenin binds to a collagen IV affinity column, and is eluted by 6.0 M urea with 1 M NaCl, pH 7.4, and the eluate contained the osteogenic activity as demonstrated in vivo. Binding of osteogenin to collagen IV is not influenced by either laminin or fibronectin. These results imply that osteogenin binding to extracellular matrix components including collagens I and IV and heparin may have physiological relevance, and such interactions may modulate its local action.

Animals↗

PubMed1989

Affinity of osteogenin, an extracellular bone matrix associated protein initiating bone differentiation, for concanavalin A.

Subcutaneous implantation of demineralized bone matrix results in bone differentiation. The bone inductive protein, osteogenin, was isolated recently by heparin affinity chromatography. The affinity of osteogenin for various lectins was examined to attain further purification and characterization. Osteogenin extracted from bovine bone matrix binds to concanavalin A (Con A) but not to wheat germ agglutinin or soybean lectin. The present data indicate that the bone inductive protein, osteogenin, is a glycoprotein. The use of a Con A Sepharose affinity column followed by preparative gel electrophoresis resulted in a greater than 250,000 fold purification of osteogenin.

Animals↗

PubMed1989

Hemoglobinopathies in a general and family practice setting.

The incidence of sickle cell trait varies among blacks in North America. Although the average hemoglobin (Hb)-AS gene frequency is 8% in the United States, a value of 13.4% was recorded in South Carolina. Preliminary studies during a two-day community sponsored health fair in Selma, Alabama, revealed a sickle cell gene frequency of 15.96%. This study also found an intermediate frequency of 12.4% in a family practice center that is accredited for a residency program. Through a screening program, sickle cell trait was detected, a rigorous training program for resident physicians in family practice was implemented, and proper counseling to patients with hemoglobinopathies was provided. In the authors' judgment, laboratory screening for sickle cell trait is a first step toward genetic counseling and medical practice by family physicians and general practitioners.

Alabama↗

PubMed1986

Prenatal antiepileptic drug exposure alters seizure susceptibility in rats.

An animal model is used to address the issue of prenatal exposure to certain antiepileptic drugs and seizure susceptibility in the offspring. Administration of doses established as median therapeutic doses in humans of phenobarbital, valproate and clonazepam to pregnant rats during the last third of gestation produced sexually dimorphic alterations in pentylenetetrazol (PTZ)-induced seizures as well as in non-convulsive (spontaneous alternation and cliff avoidance) behaviors in the offspring. Altered seizure susceptibility occurred in the absence of overtly recognizable morphological abnormalities and did not appear to reflect differences in the status of circulating drug-binding plasma proteins. Possible neural and/or metabolic mechanisms responsible for these behavioral changes are discussed.

Animals↗

PubMed1986

Evaluation of albumin-globulin ratio to confirm the clinical stages of sarcoidosis.

The serum albumin-globulin ratio (A/G) has been evaluated and correlated to confirm the clinical stages of sarcoidosis in clinically diagnosed cases. In comparing each clinical stage of sarcoidosis, using Student's t test (P = .05), a significant difference was observed. Overall, men maintained a higher A/G ratio than women in all of the clinical stages. The authors conclude that the serum A/G ratio, which can be computed from serum analyses of albumin and globulins by a suitable method, can be an additional and reliable index requiring no extra serum sample or cost per test to confirm clinical stages of sarcoidosis. This measurement can easily be used in monitoring the progression of disease or efficacy of the therapy.

Adult↗

PubMed1984

Neuraminidase production by Candida albicans.

A Candida albicans strain G42, isolated from a vaginal infection, was demonstrated to produce neuraminidase in culture filtrates with activity for N-acyl-neuraminic acid glycoprotein from bovine submaxillary gland, and human erythrocytes as substrates. Incubation of viable cells from G42 with human group O Rh(+) erythrocytes released N-acetyl-neuraminic acid in a time-dependent manner. Thirty-two clinical isolates of C albicans were studied for neuraminidase production. Enzyme activity was found in culture filtrates from five strains.It would appear important from these data to determine whether the production of neuraminidase by C albicans can be correlated with pathogenicity.

Animals↗

PubMed1983

Comparative study of the lipid composition of particular pathogenic and nonpathogenic species of Mycobacterium.

A comparative study was undertaken of lipid composition of Mycobacterium tuberculosis H(37)Rv and H(37)Ra, M avium, M phlei, and M 607. Neutral lipids and phosphatides constituted about 55 and 25 percent of the total lipids, respectively. Seven different phosphatides were isolated and identified in varying proportions in all of the above species of mycobacteria. These were polyglycerophosphatide, phosphatidic acid, phosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol dimannoside, and phosphatidylinositol pentamannoside. Choline-containing phosphatides and cholesterol (steroids) were not detected in lipids of any of the five species under these defined experimental culture medium and growth conditions. Interestingly enough, neutral lipids of M tuberculosis (H(37)Rv and H(37)Ra) contained a higher percentage of diglycerides than monoglycerides, whereas in the other species (M avium, M phlei, and M 607) the monoglyceride content exceeded that of the diglycerides. It appears that the lipid composition of mycobacteria can be an additional useful parameter in distinguishing pathogenic from nonpathogenic species of mycobacteria.

Animals↗

PubMed1982

Fatty acid composition of mycobacterial lipids as an index of pathogenicity.

Five species of Mycobacterium were analyzed for the fatty acid composition of total and neutral lipids and of individual classes of phosphatides. The methyl esters of fatty acids were analyzed using the technique of gas liquid chromatography. It was found that myristic, palmitic, palmitoleic, and tuberculostearic acids were the major fatty acids present in all of the lipid components of these strains of tubercle bacilli. The ratio of unsaturated to saturated fatty acids is lowest in the most pathogenic strain, indicating a progressive increase in this ratio, and the highest ratio is represented by a saprophytic strain. An avian pathogenic organism falls in the center of this classification among the examined strains of mycobacteria. These results indicate that the ratio of unsaturated to saturated fatty acids of lipids can be used to determine and establish the pathogenic species of mycobacteria.

Animals↗

PubMed1980

A comparison of plasma phenytoin level determinations by EMIT and gas-liquid chromatography in patients with renal insufficiency.

Monitoring the blood levels of antiepileptic drugs (AED) has proven to be of value in the clinical management of epileptic patients. We have compared the plasma concentrations of AED determined by enzyme multiplied immunoassays (EMIT) and gas-liquid chromatography (GLC) assays and identified a group of patients (n = 22) in whom the EMIT values for phenytoin were up to three times higher than those obtained by GLC. All these patients were oliguric with various degrees of azotemia, most of them undergoing weekly hemodialysis. The ratio of EMIT over GLC was 2.0 in 14 patients, 2.5 in 5 patients, and near 3.0 in 3 patients. These ratios remained relatively constant during repeated determinations over several months. The magnitude of difference between EMIT and GLC values (microgram/ml) was not related to the degree of azotemia. The discrepancy remained unchanged when various modifications of EMIT and GLC techniques were used. When phenytoin was added in vitro to plasma from nonepileptic oliguric azotemic patients, the measured phenytoin values were close to and not higher than the target values by either methodology. We feel that, when monitoring phenytoin blood levels in epileptic patients with renal insufficiency, one should be aware of a discrepancy between phenytoin values assayed by GLC and EMIT.

Chromatography, Gas↗

PubMed1978

Correlation of the "EMIT" with a gas-liquid chromatographic method for determination of antiepileptic drugs in plasma.

We report a study of the comparison of antiepileptic drugs (phenobarbital, phenytoin, primidone, and carbamazepine) by the Enzyme Multiplied Immunoassay Technique "EMIT" and the gas chromatography (GLC) method. Overall, reasonable correlations were observed for all of the above-mentioned assays by both methods in the majority of samples included in this study. Our observations for statistical and clinical differences at various levels of phenobarbital and phenytoin are discussed. A suggestion is provided in order to avoid a major discrepancy (approximately 30% higher values by EMIT vs GLC) in results observed from the "Bottom of the Bottle Effect" for EMIT reagent.

Anticonvulsants↗

PubMed1975