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Biomedical subjects

M Aslam

Publications and source records attributed to M Aslam.

At least 73 records · Page 4Linked to original sources
PubMed1998

Parameters of the rectoanal inhibitory reflex in patients with idiopathic fecal incontinence and chronic constipation.

PURPOSE: The rectoanal inhibitory reflex is a response of the internal anal sphincter to rectal distention, reflecting the functional nature of the anal sampling mechanism of rectal discrimination. The aim of this study was to assess the parameters of the rectoanal inhibitory reflex in healthy volunteers and incontinent and symptomatically constipated patients. METHODS: The rectoanal inhibitory reflex was recorded in 42 patients using reproducible threshold volumes. Excitatory and inhibitory latencies, maximum excitatory and inhibitory pressures, amplitude, and slope of inhibition, slope and time of pressure recovery, and area under the inhibitory curve were estimated. Pudendal nerve terminal motor latency and endoanal magnetic resonance imaging were performed in all incontinent patients. RESULTS: Significant linear trends were found for most parameters at each sphincter level when analyzed. Recovery time and area under the inhibitory curve differed between the sphincter levels and patient groups, with the most rapid recovery occurring in the distal sphincter of incontinent patients (P < 0.001). These pressure findings were not accounted for by differences in excitation between patient groups. CONCLUSION: A coordinated response by the internal anal sphincter to rectal distention with recovery of anal pressure from the distal to the proximal sphincter is suggested. Continence may rely on the character of internal anal sphincter inhibition, and recovery and preoperative assessment of rectoanal inhibitory reflex parameters may be important for predicting functional result following low anastomosis.

Adult↗
PubMed1998

The dependence of hepatic function upon sufficient oxygen supply during prolonged isolated rat liver perfusion.

It is unclear how the omission of a perfusate oxygen carrier may influence data derived from prolonged in vitro liver perfusions. The effects of reduced perfusate oxygen content upon liver function tests conducted in livers from male Sprague-Dawley rats perfused for 6 h, were studied using diluted rat blood (PCV = 10%) (group 1) and compared to lines perfused with Krebs' buffer (group 2). Perfusate and bile samples were withdrawn at the start and at hourly intervals following the commencement of perfusion for biochemical analysis of aspartate-serine transaminase, alkaline phosphatase, bilirubin, urea and potassium concentrations, and also for perfusate gas measurements for calculations of hepatic oxygen uptake. There were no significant differences between the initial perfusion pressures of 11.4+/-1.6 and 15.7+/-2.4 mm Hg at the start of perfusion (group 1 versus group 2, respectively). Maintenance of comparable perfusion pressures at the start of perfusion, however, resulted in a significant difference in the fixed flow rate between the two groups of 1.9+/-0.1 and 2.6+/-0.2* ml/min/g liver and resulted in significantly higher perfusion pressures in group 2 than in group 1 after 6 h of perfusion (18.2+/-2.0 versus 8.7+/-1.7 mmHg, respectively). Bile volume production was significantly greater in group 1 than in group 2, at 784+/-84 vs 458+/-75 microl/h** respectively. Hepatic oxygen uptake (HOU) was significantly greater in group 1 than in group 2, and maximal at 0.93+/-0.13 vs 0.32+/-0.08** micromol/min/g, respectively. Bile concentrations of bilirubin and potassium were significantly greater in group 1 than in group 2, 23.0+/-0.6 vs 4.9+/-0.4 micromol/l*** and 4.7+/-0.5 vs 1.1+/-0.2 mmol/l**, respectively. Perfusate concentrations of urea, bilirubin, and glucose were significantly higher in group 1 than group 2, 5.7+/-0.5 versus 1.4+/-0.2 micromol/l**; 2.4+/-0.5 versus 0.7+/-0.1 micromol/l** and 22.1+/-1.4 versus 17.8+/-0.9 micromol/l***. It is concluded that in vitro perfusion of the rat liver with Krebs'-Henseleit buffer (KHB) via the portal vein alone may be insufficient to maintain optimum liver function as assessed by the tests used. Inclusion of a perfusate oxygen carrier is optimal if livers are to be perfused at physiological pressures. *p < 0.05; **p < 0.01; ***p < 0.001; group 1 versus group 2, Student's unpaired t test.

Alkaline Phosphatase↗
PubMed1998

Differentiation between the effects of unprocessed portal blood and reduced liver function on brain indole amine metabolism in the portacaval shunted rat.

Changes in brain 5-HT turnover which have been associated with portal-systemic encephalopathy (PSE) in man were studied in rats with experimental PSE for intervals up to 15 weeks following the surgical construction of end-to-side portacaval shunts (PCS). These were compared to changes measured in portacaval transposed rats (PCT) which, show little hepatic dysfunction or cerebral abnormalities but, in common with the PCS rat, sustain total portal-systemic diversion. Thus any differences between these two groups were indicative of hepatic dysfunction and not the systemic diversion of portal blood. After 15 weeks, sustained increases were measured in brainstem and cerebral concentrations of the catabolite of 5-hydroxytryptamine (5-HT), 5-hydroxyindole acetic acid (5-HIAA), from 0.25+/-0.01 to 0.68+/-0.01*** microg g(-1) brain and from 0.18+/-0.01 to 0.31+/-0.03*** microg g(-1) brain respectively in PCS rats and were statistically greater to those measured in the brainstem and cerebrum of PCT and control rats. Sustained increases in cerebral concentrations alone of 5-hydroxytryptophan (5-HTP), the precursor of 5-HT, from 0.17+/-0.01 to 0.23+/-0.02 microg g(-1) brain were measured in PCS rats and were significantly*** greater than in PCT control rats after 15 weeks. Some early increases in 5-HTP were measured in PCS above control rats but these were not significant after 15 weeks. No sustained significant differences between the 3 groups were measured in 5-HT after 15 weeks. These data confirm previous evidence that the elevations in 5-HTP and 5-HIAA concentrations observed in experimental chronic liver failure and PSE are due to liver dysfunction and not portal-systemic diversion and may contribute additional information regarding the role of derangements in central 5-HT turnover as one of the causes of PSE. ***p<0.001, Newman-Keuls ANOVAR followed by Student's unpaired t-test for individual comparisons, (data shown are mean +/- SEM).

Animals↗
PubMed1998

Peptides generated from milk proteins in the bovine mammary gland during involution.

Proteolytic activity in mammary gland secretions is associated with hydrolysis of secretory proteins during involution. Peptides generated from hydrolysis of milk proteins were characterized in secretions from the bovine mammary gland during involution to understand the fate of the milk proteins better. Mass spectral analysis of mammary secretions showed numerous peptides ranging between 0.7 and 14 kDa during mammary involution, but these peptides were not observed in normal milk. Mass spectral profiles representing discrete peptide fragments were similar on d 7, 14, and 21 of involution, suggesting that milk proteins were only partially hydrolyzed during involution. N-Terminal amino acid sequences of four peptides indicated that they were produced by hydrolysis of beta-casein during involution and probably resulted from plasmin hydrolysis. A 20-kDa peptide was identified as a fragment of a 39-kDa protein that was previously identified in bovine mammary secretions during involution. Mass spectral analysis of lactoferrin isolated from mammary secretions during involution showed major hydrolytic products. Immunoblot analysis confirmed that lactoferrin that was isolated from mammary secretions during involution contained a number of hydrolytic products. Intramammary hydrolysis of milk proteins by plasmin probably leads to the generation of the discrete peptides observed in the mammary secretions and contributes to the fate of these proteins during involution of the bovine mammary gland.

Amino Acid Sequence↗
PubMed1998

Influence of intramammary infusion of calcium on the calcium status of periparturient lactating dairy cows.

Sixteen multiparous pregnant cows (14 Holsteins and 2 Jerseys) were arranged in a randomized complete block design and assigned to intramammary infusion of Ca (8 cows) or intramammary infusion of distilled, deionized water (8 cows). Beginning 1 wk before expected calving, plasma Ca concentration was monitored daily until calving. Immediately after the first milking postpartum, an initial (0-h) blood sample was collected via a jugular catheter; then 40 ml of either a 50% Ca borogluconate solution containing 1.6 g of Ca or 40 ml of distilled, deionized water were infused in the right forequarter of the udder. Changes in plasma Ca concentration were monitored every 10 min for the 1st h and then hourly thereafter until the next milking. This infusion and sampling protocol was applied for three consecutive milkings (36 h). Milk Ca concentration from individual quarters for each milking also was monitored. Cows infused with water had lower milk Ca concentration in the infused quarter than in the uninfused quarters during the third and fourth milkings postpartum. Milk Ca for cows infused with Ca was higher in infused quarters than in uninfused quarters at the second milking postpartum. However, this difference lessened during the third milking and was reversed during the fourth milking. Plasma Ca concentration of control cows decreased toward the end of each 12-h sampling interval but was much more stable for cows infused with Ca. The enhanced ability of cows infused with Ca to maintain plasma Ca concentration postpartum might translate into improved transition from nonlactating to lactating diets and could potentially reduce the incidence of metabolic disorders during the periparturient period. However, this response and potential side effects, such as the possibility that mastitis could accompany intramammary infusion of Ca, should be evaluated further before adopting this procedure.

Absorption↗
PubMed1998

Immunization of cows with ferric enterobactin receptor from coliform bacteria.

The serum and milk immunoglobulin (Ig) G responses of lactating dairy cows were determined following immunization with ferric enterobactin receptor FepA. Escherichia coli 471 was cultured in iron-depleted medium, and outer membrane proteins were extracted by 2% N-lauroylsarcosine sodium salt and 2% Triton X-100. The FepA was isolated from the outer membrane proteins by ion-exchange chromatography. Twenty cows were assigned to four treatment groups of 5 cows blocked by breed and days in milk. Treatment groups were vaccinated with 100 micrograms of FepA, 500 micrograms of FepA, Escherichia coli J5 bacterin, or sterile phosphate-buffered saline. Primary immunization was at approximately 200 d in milk, and booster immunizations were given 14 and 28 d later. Serum and whey IgG titers to FepA in cows vaccinated with FepA were significantly higher than those from cows vaccinated with either E. coli J5 bacterin or phosphate-buffered saline. Serum and whey IgG titers to FepA were elevated by 14 d in cows vaccinated with FepA. Significant differences were not observed between doses of FepA. The degree of cross-reactivity of purified IgG from cows vaccinated with FepA to E. coli and Klebsiella pneumoniae isolates was significantly higher than that to a control isolate that lacked FepA production. Immunization with FepA elicited an immunological response in serum and milk.

Ammonium Sulfate↗
PubMed1998

L-carnitine administration in coronary artery disease and cardiomyopathy.

Myocardial ischaemia may be defined as a deficiency in cardiac energy supply relative to energy demand. In coronary artery disease (CAD), oxygen supply is limited due to coronary obstruction so energy production is not enough to meet the energy demands for work. Several reports involving about 2500 patients of CAD where carnitine was administered for upto 1 year indicate some beneficial effects. There is reduction in ischaemia showing reduced ST-segment depression and angina, greater effort tolerance and decreased need of cardiac drugs. Carnitine can cause overall improvement in cardiac performance in patients with CAD as well as in cardiomyopathy. More studies are necessary to demonstrate where carnitine can scavenge free radicals apart from its beneficial effect on fatty acid metabolism. Side effects of carnitine are mild nausea and vomiting and dose upto 2 g/day in 3 divided doses may not have any side effects. Intravenous L-carnitine acts rapidly and has no side effects.

Carnitine↗
PubMed1997

Antioxidant effects of lovastatin and vitamin E on experimental atherosclerosis in rabbits.

The effects of the administration of vitamin E (10 mg/day) plus lovastatin (2 mg/day; group A, n = 10), lovastatin alone (2 mg/day; group B, n = 10), and placebo (group C, n = 10) were compared over 24 weeks in a randomized, single-blind controlled trial. All groups of rabbits received a trans fatty acid (TFA)-rich diet (5-10 g/day) for 36 weeks. Treatment with vitamin E plus lovastatin (group A) and lovastatin (group B) started after 12 weeks of administration of TFA-rich diet was associated with a significant but similar decline in serum cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides in both groups at 36 weeks. Lipid peroxides and diene conjugates showed a significant decline in association with a significant increase in the plasma level of vitamin E in group A rabbits at 36 weeks. However, the lovastatin group B showed a lesser but significant decrease in lipid peroxides and diene conjugates at 36 weeks, indicating that lovastatin may have antioxidant activity. In control group C, the increase in blood lipids and oxidative stress at 36 weeks was much greater than the decrease in groups A and B. After experimental lipid peroxidation at 24 weeks in all of the rabbits, 2 of 10 group B and 3 of 10 group C rabbits died due to coronary thrombosis; there were no deaths in group A. Thus antioxidant therapy with vitamin E can provide protection against death due to free radical stress. Aortic lipids and sudanophilia indicating athorosclorosis were significantly lower in groups A and B than in group C. The atherosclerotic coronary plaque sizes were significantly smaller in group A (18.5 +/- 3.6 microns) than in groups B (41.6 +/- 4.2 microns) and C (85 +/- 6.7 microns). Aortic plaque sizes were also smaller in group A than in group B and C. It is possible that antioxidant therapy with vitamin E, as an adjunct to lipid lowering with lovastatin, can provide additional benefit in the inhibition of oxidative stress and atherosclerosis. The antioxidant activity of lovastatin has not been reported, to our knowledge.

Animals↗
PubMed1997

The anti-proliferative effect of plasma from rats with acute fulminant hepatic failure.

BACKGROUND: During fulminant hepatic failure (FHF) metabolites normally cleared by the liver accumulate in the circulation and cause hepatic coma. It is believed that the plasma of FHF patients has an inhibitory effect on liver regeneration. Plasma exchange was used to study the effect of plasma collected from donor FHF rats on liver regeneration in two-thirds partially hepatectomized syngeneic animals. METHODS: FHF and hepatic coma were induced in donors by administration of galactosamine at a dose of 1.85 g/kg. Plasma from donors in either grade-II or -IV coma was transfused by plasma exchange into partially hepatectomized animals 2h after resection. RESULTS: The livers from donor animals showed evidence of oval cell activation 1-2 days after galactosamine, but differentiation of oval cells to hepatocytes did not occur before the development of coma. The plasma collected from animals in grade-IV coma totally abolished regeneration in the partially hepatectomized recipients. CONCLUSION: These results support the hypothesis that metabolites present in the plasma during FHF inhibit liver regeneration.

Acute Disease↗
PubMed1997

Proteolysis of milk proteins during involution of the bovine mammary gland.

The role of proteolytic hydrolysis of milk proteins in the mammary gland during involution is unknown. The objectives of this study were to determine the activities of plasmin, plasminogen, and plasminogen activator in mammary gland secretions collected during involution and to identify peptides generated by proteolysis of casein and lactoferrin in those secretions. Mammary secretions were collected from Holstein cows on d 7, 14, and 21 of involution and on d 7 postcalving. Activities of plasmin, plasminogen, and plasminogen activator were determined on the defatted, filtered aqueous phase of mammary secretions. Activities of plasmin, plasminogen, and plasminogen activator were significantly higher on d 7, 14, and 21 of involution than were those on d 7 postcalving. Protein fragments resulting from hydrolysis were detected by SDS-PAGE in samples collected on d 7, 14, and 21 of involution, but few protein fragments were observed in samples collected on d 7 postcalving when plasmin activity was low. Immunoblot analysis showed that a number of peptides observed during involution were generated from alpha s-casein (CN), beta-CN, kappa-CN, or lactoferrin. The appearance of peptides from proteins of mammary secretions during early involution was generally correlated with increased plasmin activity. Elevated plasmin activity during mammary involution may be primarily responsible for the observed concurrent hydrolysis of milk proteins in mammary secretions.

Animals↗
PubMed1996

Infrared optoelectronic volumetry, the ideal way to measure limb volume.

OBJECTIVES: The aim of the study was to compare a novel infrared optoelectronic system (Perometer) of limb volume measurement with water displacement and two indirect measurement techniques. DESIGN: A prospective experimental study. METHODS: In 10 healthy male volunteers (20 limbs) we compared limb volume measurements obtained by water displacement, infrared perometry, the disc model method and the frustrum method. In a further 17 patients with swollen limbs due to lymphatic (9 limbs) or venous (11 limbs) disease, perometry was compared to the disc model method and the frustrum method only. RESULTS: In normal limbs, mean +/- S.D. limb volume using water displacement was 1802 +/- 268 ml. Perometer values agreed almost exactly (1809 +/- 262 ml, r = 0.97, variation +/- 7% by limits of agreement) but both the disc (1923 +/- 306 ml, r = 0.90, variation +/- 14%) and frustrum (1905 +/- 372 ml, r = 0.72, variation +/- 28%) methods significantly overestimated limb volumes (p < 0.05 (ANOVA, Fisher's Least Significant Difference)). In diseased limbs perometer, disc method and frustrum method results were 2415 +/- 995 ml, 2494 +/- 969 ml, and 2413 +/- 870 ml representing variation of +/- 17% and +/- 23% for disc method and frustrum method respectively compared to perometry. CONCLUSIONS: Perometry is a novel, extremely accurate and easy method for assessing limb volume. It provides more accurate results than traditional indirect measurement of limb volume and potentially is a very useful clinical and research tool.

Analysis of Variance↗
PubMed1996

Stability of radiopharmaceuticals during administration to the intensive care patient.

Nuclear medicine can provide useful data when monitoring the organ function of patients undergoing intensive care. Test procedures involve the administration of radiopharmaceuticals and external monitoring using gamma cameras or nuclear probes. The radiopharmaceuticals required may be given at lower doses than normally used in routine nuclear medicine imaging, are ideally available 24 h a day and are preferably administered via indwelling cannulae and giving sets. Three radiopharmaceuticals have been studied; a renal function agent, a hepatobiliary function agent and a product used for in vivo labelling of protein for lung permeability studies. Under conditions of storage, dilution and passage through giving sets (simulating conditions found during administration in the intensive care setting), some instability can be demonstrated in each product, which could result in the tests giving rise to wrong or misleading data. It is recommended that radiopharmaceuticals are not diluted excessively, and that where possible, parenterally-administered products are given by direct intravenous injection and not through giving sets.

Critical Care↗
PubMed1996

Effect of root perturbation and excision on nitrate influx and efflux in barley (Hordeum vulgare) seedlings.

The effects of perturbation and excision on net NO3- uptake, influx and efflux in roots of 8-day-old barley (Hordeum vulgare L.) seedlings induced with NO3- or NO2- were determined. Perturbation was simulated by mechanically striking the intact roots with a glass rod. Perturbation or excision of roots and subsequent division into small segments had little effect on NO3- influx, but briefly inhibited net uptake which recovered within a few min. While in perturbed roots net uptake rates recovered to the same level as in control roots, full recovery did not occur in excised roots. Inhibition of net uptake was due to stimulation on NO3- efflux. The recovery time and level of inhibition of net NO3- uptake and/or stimulation of efflux were a function of extent of perturbation, or the number of segments following excision, and root NO3- concentration. NO3- efflux was further stimulated when roots were perturbed after cytoplasmic NO3- had been depleted, indicating that both the plasmalemma and tonoplast may be affected. In excised roots both NO3- influx and efflux decreased with age due to depletion of energy sources. The results indicate that root perturbation and excision had no effect on NO3- influx but inhibited net uptake by stimulating efflux.

Glucose↗
PubMed1996

Enicostema littorale: a new source of swertiamarin.

Enicostema littorale a useful medicinal herb was subjected to phytochemical as well as pharmacological investigations. A secoiridoid glycoside, swertiamarin, was isolated and identified on the basis of UV, IR, Mass and NMR spectroscopic measurements. However, pharmacological studies on the blood pressure of rats and ileum of Guinea-pig could not provide significant results.

Journal Article↗
PubMed1996

Changes in plasma electrolytes during acclimatization at high altitude.

The effects on plasma electrolytes and related hormones were determined in non-acclimatized low lander males, exposed for 96 hours to an altitude of 4424 meters. Twenty healthy soldiers aged 18-34 years travelled by road from an altitude of 2303 meters to 4424 meters over a period of 10 hours. Plasma sodium levels (142.09 +/- 1.14 mmol/1) and aldosterone (16.61 +/- 5.70 ng/ml) decreased to 139.69 mmol/1 and 11.6 +/- 4.60 ug/ml respectively after 96 hours of acute exposure to high altitude (p < 0.05). The plasma potassium and chloride levels did not show significant change, while, plasma HCO3 decreased gradually from 21.06 +/- 1.38 mmol/1 to 18.55 +/- 0.82 mmol/1 after 96 hours exposure to this altitude (p < 0.01). The plasma ionized calcium and plasma phosphate concentration decreased from 1.32 +/- 0.11 mmol/1 and 1.58 +/- 1.3 mmol/1 to 1.20 +/- 0.05 mmol/1 and 1.47 +/- 0.99 mmol/1 respectively (p < 0.05). Plasma parathyroid hormone (PTH) level increased from 4.54 +/- 2.1 ng/ml to 11.19 +/- 4.31 ng/ml after 48 hours with subsequent decline to 2.52 +/- 1.7 ng/ml after 96 hours exposure to high altitude. It may be concluded that the process of acclimatization to sudden exposure to high altitude is characterised by fall in plasma aldosterone and PTH with subsequent decrease of related electrolytes.

Acclimatization↗