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Biomedical subjects

M Hariharan

Publications and source records attributed to M Hariharan.

53 records · Page 3Linked to original sources
PubMed1988

Amitriptyline-induced supersensitivity of a central muscarinic mechanism: lithium blocks amitriptyline-induced supersensitivity.

Chronic treatment with amitriptyline produces dose-dependent super-sensitivity of a central muscarinic cholinergic mechanism involved in the regulation of core body temperature. The authors demonstrated that chronic treatment with lithium prevents the induction of this response. The potential clinical and theoretical significance of this finding is set forth.

Amitriptyline↗
PubMed1988

Diet, pancreatic function, and chronic pancreatitis in south India and France.

The usual consumption of calories, fat, protein, and carbohydrate, and the exocrine pancreatic function estimated in duodenal juice after an intravenous injection of secretin and cholecystokinin (CCK), have been studied with the same method and by the same team in Kerala (South India) and in Marseille (France) in apparently normal children (7 Indians, 21 French), in normal adults (23 Indians, 17 French), and in patients presenting with chronic calcifying pancreatitis (8 Indian children, 28 Indian adults, 25 French adults). Although they had a low protein intake (children controls: 32.1 +/- 14 g/day (SM), children pancreatitis: 51.1 +/- 15, adult controls: 51.3 +/- 4.9, adult pancreatitis: 55.7 +/- 5.7), the exocrine secretion of Indian controls was not very much modified in comparison with Europeans. Therefore, Indians are less affected by the insufficient diet than the population of Ivory Coast previously studied by the same group. The diet of Indian patients is characterized by a moderately low protein intake and a very low fat intake (18.5 g/day +/- 2.3 (SM) for children 23.4 g/day + 2.7 for adult patients). Comparison between different series of patients studied in different countries with the same method suggests that kwashiorkor or cassava consumption have no evident role in the etiology of chronic tropical pancreatitis. The possible role of a low fat diet is suggested and needs further exploration.

Adolescent↗
PubMed1988

A high-performance liquid-chromatographic method for routine simultaneous determination of nicotine and cotinine in plasma.

We describe a rapid, sensitive method for the routine simultaneous determination of nicotine and cotinine in 1 mL of plasma. Extraction in 10-mL screw-capped Teflon tubes with methylene chloride after deproteinization with trichloroacetic acid eliminated emulsion formation. The extract, after evaporation and reconstitution in 30 microL of mobile phase, is injected into a reversed-phase C-18 ion-pair column of an isocratic high-performance liquid-chromatographic unit. Absorbance is monitored at 256 nm. The mobile phase is a citrate-phosphate (30 mmol each per liter) buffer mixture containing 50 mL of acetonitrile and 1 mmol of sodium heptanesulfonate per liter. 2-Phenylimidazole is the internal standard. The detection limit is 1 microgram/L for nicotine and 3 micrograms/L for cotinine. The standard curve is linear from 0 to 700 micrograms/L for both compounds. The average CV for nicotine in the concentration range 0-100 micrograms/L is 6.5%, and that for cotinine in the concentration range 50-700 micrograms/L is 4%.

Chromatography, High Pressure Liquid↗
PubMed1985

Endoscopic pancreatography in chronic pancreatitis of the tropics.

The ERCP findings in 13 patients with chronic pancreatitis of the tropics are reported. 7 of the patients had pancreatic calculi on plain film of abdomen and 6 had no calcification. The changes observed in the pancreatograms were tortuosity, dilatation, stenosis, obstruction, cyst formation and presence of calculi in the main pancreatic ducts and their finer branches. The calcific variety showed a greater degree of ductal derangement compared to the non-calcific variety. The common bile duct was normal in all the patients. The pancreatographic changes observed are similar to those described in the alcoholic and other varieties of chronic pancreatitis.

Adolescent↗
PubMed1985

Persistence of polybrominated biphenyls (PBB) in human post-mortem tissue.

Polybrominated biphenyl (PBB), a fire retardant, was accidentally substituted for an animal feed supplement in Michigan 10 years ago. This led to widespread livestock contamination and ultimately to contamination of virtually every human residing in the State at that time. In order to evaluate the extent of PBB persistence and distribution in human tissues 10 years after this accidental poisoning, a study was conducted on a series of autopsy cases from the Grand Rapids ("high" exposure) area of the State. No attempt was made to relate cause of death to PBB exposure or tissue concentration. Samples of 196 tissues from 15 subjects were analyzed for PBB content, and levels were determined by measurement of the hexabromobiphenyl peak using electron capture gas chromatography. Only 4 of the 196 samples analyzed did not have PBB concentration above the limit of detection (0.5 ng/g). As expected, fat and fat-rich tissue had the highest PBB concentration. Perirenal fat had the highest mean concentration (475 ng/g). Adrenal, atheromatus aorta and thymus had mean concentrations about half that of perirenal fat; all other tissues had mean concentrations one-tenth or less of perirenal fat. The results document that PBB is still present in human tissue and that PBB was distributed in all tissues examined. The PBB fat elimination half-time was estimated to be at least 7.8 years. If this is approximately correct, PBB will persist in tissues throughout the lifetime of humans so contaminated.

Adipose Tissue↗
PubMed1984

Anaemia and menstrual blood loss studies in women using multiload Cu250 and progestasert IUDs.

Two to 9 months following insertion of the ML Cu250 (n = 54) and Alza T (n = 30) IUDs, mean menstrual blood losses (MBL) were 46.3 ml and 32.7 ml, respectively (p less than 0.005). Significantly more of the Alza T users had losses below 40 ml and they also perceived their menses to be lighter. Based on a haemoglobin level of 12gm/dL, the upper normal limit of MBL was about 40 ml. These findings are consistent with earlier observations that during the first year, ferritin levels fall in ML Cu250 users whereas they are unaltered in Alza T users.

Adult↗
PubMed1983

Effect of laparoscopic sterilization and insertion of Multiload Cu 250 and Progestasert IUDs on serum ferritin levels.

Blood haemoglobin and serum ferritin levels were measured at the initial visit and 12 months following sterilization and IUD insertion. Ferritin levels were unaltered in Progestasert users after 12 months but haemoglobin values increased though not significantly. Ferritin levels fell in Multiload Cu 250 users and in sterilized women; haemoglobin levels were also observed to fall but significantly only in the latter group. Iron-deficiency anaemia was prevalent at initial contact and there appeared to be an increased risk subsequently in Multiload Cu 250 users and in those who were sterilized. Screening and monitoring for anaemia is indicated. From the viewpoint of iron status, the Progestasert is preferable to the Multiload Cu 250 but it suffers the major disadvantages of needing frequent replacement and of causing menstrual disturbances which might compromise its acceptability. Menstrual blood loss studies may help explain why anaemia develops after sterilization.

Adult↗
PubMed1982

Iron-deficiency anemia and long-term use of copper-bearing IUDs.

The increase in menstrual blood loss (MBL) caused by IUDs may result in iron deficiency anemia. 60 women completing 2 years of Cu-IUD use were investigated for this risk, using hemoglobin concentration serum iron indices. No significant differences were found compared to a control group of women requesting interval Cu-IUD insertion. A decrease in the MBL increment with time following insertion, self-selection of the study population, and increased dietary iron absorption are suggested explanations for these results. 15.4% of patients suffered from iron deficiency anemia. Measurement of serum ferritin is advocated to identify these women for treatment, in order to enhance maternal health.

Age Factors↗
PubMed1980

A longitudinal study of serum iron indices and haemoglobin concentration following copper-IUD insertion.

The increase in menstrual blood loss associated with copper-bearing IUDs may cause or aggravate pre-existing anaemia. In order to evaluate this risk, 84 Malaysian women wearing copper-IUDs were studied longitudinally by means of serial measurements of blood haemoglobin concentration (Hb), serum iron (S/Fe) and transferrin saturation (T/S). The initial Hb was under 12 gm% in 33.7% of patients. The mean Hb showed no significant change up to 12 months while S/Fe fell significantly at the end of this time; the T/S was significantly reduced as early as 6 months post-insertion. There is a significant risk of anaemia following copper-IUD insertion, particularly with long-term usage. Progestogen-releasing IUDs may offer the most feasible solution to this problem in our local context since oral medication with iron or drugs to reduce menstrual blood loss is not practicable.

Adult↗
PubMedDate not supplied

Solvent, emulsifier and drug concentration factors in poly(D,L-lactic acid) microspheres containing hexamethylmelamine.

Biodegradable poly(D,L-lactic acid) (PLA) microspheres containing hexamethylmelamine (HMM) were developed for potential use in chemoembolization and intraperitoneal implantation. The emulsion-solvent-evaporation/extraction method was used to prepare 15 formulations with different drug/polymer ratios, solvent compositions and emulsifer concentrations in the continuous aqueous phase. A central composite experimental design was used, with five levels of the three different factors. All formulations resulted in the formation of discrete matrix microspheres containing crystalline drug. The mean particle sizes of the microsphere formulations ranged from 62-348 microm and the effect of the independent variables on microsphere size was satisfactorily predicted using response surface methodology. For theoretical drug loads of 5-40%, efficiency of entrapment ranged from 75-107% and porosities of the microspheres were between 0-6.5%. The rate of drug release from the microspheres depended on drug loading and particle size. Microspheres with 22.5% or greater theoretical drug content released drug rapidly, with almost complete release occurring in 70 h or less. Formulations with drug loading of 5% and 9.57%, however, released drug very slowly, with less than 50% released in 40 days. Release kinetics of narrow sieve cuts of microspheres with high drug load (35.4%) followed square root of time profiles.

Altretamine↗
PubMedDate not supplied

Venous plasma epinephrine levels and the symptoms of stress.

It is widely believed that increases in circulating epinephrine (adrenaline) levels contribute substantially to the physical sensations (symptoms) associated with stress. Using a drug discrimination choice procedure, it was demonstrated that the plasma epinephrine levels at which healthy human subjects reliably discriminate between infusions of epinephrine and saline are higher than the levels typically observed in situations of mental stress. Choice of epinephrine versus saline was strongly associated with a subjective perception of a change in the action of the heart, but only moderately associated with the venous plasma epinephrine levels attained and only weakly associated with actual changes in heart rate and peripheral blood pressure. These results imply that epinephrine release from the adrenal gland plays at most a small role in the production of the somatic symptoms of mental stress.

Adult↗
PubMedDate not supplied

Platelet alpha 2-adrenoreceptors, catecholamines, hemodynamic variables, and anxiety in panic patients and their asymptomatic relatives.

The objectives of this study were to a) replicate our prior finding of a decreased number (Bmax) of platelet alpha 2-adrenoreceptors in panic disorder, b) determine if binding is also decreased in asymptomatic first-degree relatives of panic patients (known to be at increased risk for developing panic), and c) evaluate the effect of treatment on the presumptive decrease in binding (i.e., is the decrease a state or a trait marker for panic?). Panic patients had clonidine and yohimbine platelet-binding assays, symptom ratings, and measurement of lying and standing plasma epinephrine, norepinephrine, systolic and diastolic blood pressure, and heart rate before treatment, after approximately 2 months of medication (fluoxetine, tricyclics, or alprazolam) and/or cognitive behavioral treatment, and after symptom remission while drug free; normal subjects had determinations of the same measures at approximately the same time intervals. Relatives of both groups had one determination only of all measures. Tritiated clonidine binding was decreased and lying heart rate was increased in patients before treatment. Magnitude of binding decrease was correlated with symptom severity and standing norepinephrine. No binding abnormality was seen in first-degree relatives of patients. Treatment increased clonidine binding in patients. Both patients and relatives of patients showed significantly increased standing plasma norepinephrine in comparison to controls. There is a state-related decrease in binding, associated with symptom severity and norepinephrine, in panic disorder. Abnormal reactivity of norepinephrine to standing might be a marker for increased likelihood of panic development in individuals at risk.

Adult↗
PubMedDate not supplied

Rectal varices in extrahepatic portal hypertension.

Rectal varices, as distinct from haemorrhoids, occur due to high pressure in the inferior mesenteric venous system in patients with portal hypertension. The exact prevalence of rectal varices in extrahepatic portal hypertension is unknown. To determine this, 116 patients with extrahepatic portal hypertension were studied for the presence of rectal varices. These lesions were found in 103 (88.8%) patients. Bleeding from rectal varices occurred in 14.6% of patients. Massive bleeding requiring hospitalization and blood transfusion was not encountered. It is concluded that rectal varices are common in extrahepatic portal hypertension. Bleeding from them is uncommon, and often mild and self-limiting. The available literature is reviewed and the importance of recognizing the condition stressed.

Adolescent↗
PubMedDate not supplied

A case-control study on risk factors for pancreatic diseases in Kerala, India.

BACKGROUND/AIMS: We simultaneously conducted case-control studies, in Kerala of South India, on chronic calcific pancreatitis of the tropics (CCPT), pancreatic ductal adenocarcinoma (PDA) with CCPT, and PDA alone to assess similarity of and difference between their risk factors. METHODOLOGY: Cases with one of these diseases were identified at the Trivandrum Medical College (TMC) Hospital, in Kerala, from 1994 to 1996. Controls were selected from healthy hospital visitors of the TMC Hospital by individual age (within +/- 3 years) and sex-matched with the index case. Odds ratios and their 95% confidence intervals for potential risk factors were calculated. RESULTS: Frequent consumption of cassava was positively associated with the risk of PDA with CCPT. Heavy cigarette smoking and drinking large amounts of coffee and/or tea everyday were positively related to the risk of PDA alone. Frequent consumption of vegetables and/or fruits was correlated to the decreased risk of PDA alone. CONCLUSIONS: Risk factors as well as preventive factors seem to be different between PDA with CCPT and PDA alone. Further study is necessary, especially to clarify the prognostic factors which would induce pancreatic malignancy in patients with CCPT.

Adolescent↗