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Biomedical subjects

R C Arora

Publications and source records attributed to R C Arora.

At least 91 records · Page 5Linked to original sources
PubMed1982

Serotonin uptake in subpopulations of normal human blood platelets.

Serotonin uptake was studied in platelet-rich plasma with different proportions of heavy (young) and light (old) platelets. The maximum velocity of serotonin uptake, a measure of the number of uptake sites (Vmax), was greater in the heavy platelets than in the light platelets. However, the uptake sites in the lighter platelets had an increased affinity (Km) for serotonin compared to the heavy platelets, which could compensate for the decreased number of uptake sites. These results indicate differences in Vmax of 5-HT uptake in particular populations could be due to differences in the relative proportions of heavy and light platelets.

Blood Platelets↗
PubMed1981

A modified assay method for determining serotonin uptake in human platelets.

Effects of various experimental conditions on serotonin (5-HT) uptake in human platelets were examined. The experimental design allowed the evaluation of the effect of diffusion and other non-saturable processes on the affinity and maximum activity of the membrane pump for 5-HT uptake. Total 5-HT uptake was determined by incubating platelet-rich plasma (PRP) with increasing concentrations of serotonin at 37 degrees C for 4 min. The passive uptake was measured by the addition of various 5-HT concentrations to PRP in buffer at 37 degrees C, followed by immediate transfer to an ice-cold water bath. The difference between the total and passive uptake was linear for 6 min. The affinity (Km) for active platelet serotonin uptake was 0.45 +/- 0.09 mumol/l and maximal rate of uptake (V) was 10.7 +/- 2.1 pmol/10(7) platelets/min. The described method provides a convenient and reliable measure of active 5-HT uptake suitable for clinical investigation. The effect of passive diffusion on kinetic parameters is discussed.

Blood Platelets↗
PubMed1981

Serotonin uptake in blood platelets of psychiatric patients.

Platelet serotonin (5-HT) uptake was determined in 72 newly admitted, unmedicated psychiatric patients. Decreased maximum velocity (Vmax) of 5-HT uptake was present in unipolar and bipolar depressed patients as well as schizoaffective depressed patients. The apparent Michaelis constant (km) of 5-HT uptake was normal in these groups, as was Vmax and Km in manic-depressive and chronic schizophrenic patients. Treatment of depressed patients with notriptyline hydrochloride or imipramine hydrochloride increased Km significantly. There was a trend for the increase in Km in the nortriptyline-treated patients to correlate with clinical improvement. Decreased 5-HT uptake in platelets provides additional evidence for the role of 5-HT in the pathophysiologic process of some forms of depression.

Adult↗
PubMed1981

Comparative effect of clofibrate, garlic and onion on alimentary hyperlipemia.

The effect of clofibrate on the same subjects in similar test conditions were used as a control to verify the alleged beneficial effects from garlic and onion on alimentary hyperlipemia in normals and in cases with ischemic heart disease. The results showed that clofibrate checked the fat-induced (a) rises of serum triglyceride and plasma fibrinogen, and (b) falls of coagulation time (CT) and blood fibrinolytic activity (BFA). Only garlic had a clofibrate-like effect on CT but both garlic and onion checked the postprandial fall of BFA. Clofibrate, however, increased BFA even above the fasting level. Serum cholesterol and beta-lipoprotein were not appreciably affected by fat with or without any drug. Thus, surprisingly, the so-called beneficial effects of garlic and onion were not seen in subjects who had shown significant changes after clofibrate.

Adult↗
PubMed1981

The long-term use of garlic in ischemic heart disease--an appraisal.

The hypocholesterolemic and fibrinolysis-enhancing properties of garlic were assessed in patients with ischemic heart disease (IHD) and in healthy control subjects. The peak of blood fibrinolytic activity (BFA) achieved at the 4th week of garlic therapy was not sustained despite its continuous use and returned to about the pre-garlic values at the 12th week. Garlic withdrawal did not cause any further change in BFA. Under the same conditions serum total cholesterol (STC) values did not show any significant change. Both of the foregoing features were observed in the IHD as well as in the control group. Garlic therapy for 12 weeks did not cause any appreciable changes in serum triglyceride, beta-lipoprotein, plasma fibrinogen levels or coagulation time in either IHD or control subjects. The evidence cited above does not appear to substantiate the prevalent popular belief in the efficacy of garlic in the management of IHD either as a hypocholesterolemic or as a fibrinolytic agent.

Adult↗
PubMed1981

Effect of chlorpromazine treatment on monoamine oxidase activity in platelets isolated by the Corash method.

The effect of chlorpromazine treatment on platelet monoamine oxidase (MAO) activity was compared in platelets isolated by the Corash method, which harvests essentially all the platelets in a blood sample, and a single centrifugation method, which yields 45-65% of the platelets. A highly significant decrease in platelet MAO activity following chlorpromazine was found in platelets obtained from the same subjects by both methods. The decrease observed by the two methods was significantly correlated. These results indicate the degree of decrease in MAO activity associated with chlorpromazine is not due to isolation of a subpopulation of platelets with low MAO activity by the single centrifugation method.

Blood Platelets↗
PubMed1981

Biochemical changes in the cervical mucus of buffalo after induction of oestrus with prostaglandin F-2 alpha and cloprostenol.

Prostaglandin F-2 alpha and cloprostenol were given as an i.m. injection on Days 9 or 15 of the cycle. There was a significant decline (P less than 0.01) in the concentration of protein and activities of acid and alkaline phosphatase and peroxidase in cervical mucus after treatments, and the change was more marked in animals that responded by becoming oestrous within 4 days of treatment. Values in control animals remained steady or increased.

Alkaline Phosphatase↗
PubMed1981

Platelet monoamine oxidase. I: Effect of temperature, anticoagulant, and centrifugation technique.

Platelet yield and monoamine oxidase (MAO) activity per platelet in platelets obtained by the method of Corash, which isolates essentially all platelets from whole blood, and by a single differential centrifugation of whole blood, were compared. Platelets recovered by one spin in a swinging bucket rotor appeared to be a homogeneous population containing a reliable representation of the platelet population obtained by the Corash method since the MAO specific activity yielded by the two methods was not significantly different. The effect of the anticoagulant, temperature, and type of rotor on platelet recovery from blood and MAO activity/platelet were also studied. The MAO and plasma amine oxidaze (PAO) activities obtained from blood anticoagulated with ethylenediaminetetracetate (EDTA) were significantly greater than those found when acid-citrate-dextrose was the anticoagulant. Blood centrifuged in a swinging bucket rotor at room temperature yielded 80-90% of total platelets as compared to the 45-65% recovered with a fixed-angle rotor at 0-4 C. The most efficient method of platelet isolation was found to be a 2 1/2-min room-temperature spin at 600 X g with a swinging bucket rotor using EDTA as anticoagulant.

Adult↗
PubMed1980

Skeletal muscle MAO activity in the major psychoses. Relationship with platelet and plasma MAO activities.

The skeletal muscle MAO activity of schizophrenics and patients with bipolar and unipolar affective psychoses was lower than that of normal controls. Both platelet and plasma MAO activity was significantly lower in the schizophrenics and patients with undiagnosed psychoses than in the normal controls. Platelet and plasma MAO activities were not correlated with skeletal muscle MAO activity. Both human platelet and skeletal muscle MAO are type B MAO and have similar kinetic constants. The decrease in skeletal muscle MAO activity in various types of psychotic patients is consistent with previous suggestions based on platelet studies that low MAO activity may be a nonspecific factor contributing to the development of different forms of psychopathology. Since total skeletal muscle MAO activity is the largest source of MAO in the body, it is possible that the decrease in muscle MAO activity may lead to excessive quantities of biogenic amines that could adversely affect neural activity.

Adolescent↗
PubMed1980

Milk progesterone levels to monitor reproductive status of Murrah buffalo.

Concentration of progesterone in whole milk was used to diagnose pregnancy in 44 lactating buffaloes. Milk samples were taken from days 19 to 27 post breeding and analysed for progesterone by radio-immunoassay. A level exceeding 10 ng/ml of milk was taken as an indication of pregnancy. Using this criterion, the accuracy of the pregnancy test from a single milk sample on 19, 21, 23, 25 and 27 days after insemination ranged from 71.42 to 86.95% and 86 to 87.50% for pregnant and non-pregnant animals, respectively. Milk progesterone concentrations were significantly higher (P / 0.001) in pregnant compared with those in non-pregnant buffaloes on day 19, 21, 23, 25 and 27 post-insemination.

Journal Article↗
PubMed1980

Effect of prostaglandin F(2alpha)- thamsalt and Estrumate (ICI 80996) on plasma progesterone levels in Indian water buffaloes (Bubalus bubalis ).

Thirty six buffalo showing normal reproductive cyclas were given a single intramuscular injection of prostaglandin F(2alpha)- thamsalt (PGF(2alpha)) and Estrumate on day 9 or 15 of the estrous cycle in order to induce estrus. In PGF(2alpha) treated animals, plasma progesterone dropped from 2.99+/-0.29 to 0.10 +/- 0.02 ng/ml and from 5.53 +/- 0.53 to 0.09 +/- 0.03 ng/ml (mean +/- SEM) within 72 hours of treatment, on day 9 and 15, respectively. Similarly, the treatment with Estrumate on day 9 or 15 of the cycle reduced the level of proges--terone from 3.02 +/- 0.03 to 0.14 +/- 0.03 ng/ml and from 4.26 +/- 0.47 to 0.21 +/- 0.03 ng/ml, respectively, 72 hours aPter each treatment. It was inferred that both drugs induce estrus in buffalo without any observed residual effect.

Journal Article↗
PubMed1980

Brain and skeletal muscle monoamine oxidase activity in schizophrenia.

Monoamine oxidase (MAO) activity has been studied in postmortem brain specimens from chronic schizophrenics and comparison groups by various laboratories. There is no evidence for decreased MAO activity in the brains of the schizophrenic patients, but many possible sources of error in postmortem studies make the conclusions of these studies less than definitive. However, since almost complete inhibition of brain MAO activity appears necessary before it has any functional significance, reduced brain MAO activity is unlikely to have any significance for the pathogenesis of psychosis. Brain and platelet MAO activities in man have been found not to be significantly correlated with each other. There is some evidence neuroleptic drugs may inhibit human brain MAO activity in vitro, but indirect evidence from spinal fluid and postmortem studies is not consistent with this. Decreased MAO activity has been found in the skeletal muscle of various types of psychotic patients compared to normal controls. This suggests decreased MAO activity in peripheral tissues may be a nonspecific marker for vulnerability to the development of psychopathology.

Antipsychotic Agents↗
PubMed1980

Platelet monoamine oxidase and plasma amine oxidase in psychiatric patients.

Platelet monoamine oxidase (MAO) and plasma amine oxidase (PAO) activities were determined in 70 normal controls and 76 psychiatric patients. Platelet MAO activity did not differ between the normal controls and patients diagnosed as schizophrenic or primary affective illness, although there was a strong trend for chronic schizophrenics to have lower MAO activity. Schizophrenic patients with Schneiderian-type hallucinatiions had significantly lower MAO activity than normal controls or schizophrenic patients who did not hallucinate. There was no relationship between hallucinations and platelet MAO activity in patients with affective psychoses. Paranoid schizophrenics did not have significantly different MAO activity from nonparanoid schizophrenics. PAO activity was generally lower in all diagnostic groups than in normal controls, but the results were statistically significant only for acute schizophrenics.

Affective Disorders, Psychotic↗