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Biomedical subjects

M Aslam

Publications and source records attributed to M Aslam.

At least 19 recordsLinked to original sources
PubMed1995

Hepatic function during prolonged isolated rat liver perfusion using a new miniaturized perfusion circuit.

Previous designs of isolated rat liver perfusion circuits used for toxicological investigations are often expensive, cumbersome, or traumatic in relation to hepatic biocompatibility following extended perfusion times. A new, miniaturized circuit that incorporates a novel design of organ bath, to maintain a buoyant preparation, and a high-efficiency miniaturized membrane tubing oxygenator is described. Livers from male Sprague-Dawley rats were perfused continuously for 6 hr in vitro using rat blood diluted to a perfusate hematocrit of 9.75 +/- 0.35% with Krebs-Henseleit buffer (KHB). Hepatic function was evaluated by measurement of perfusion pressure, flow rate, bile volume production, bile bilirubin content, hepatic oxygen uptake (HOU), bromosulphthalein (BSP) removal, hepatic enzyme activities, and electrolyte concentrations, and finally by histological examination. Perfusion pressure and flow rate remained stable at 8.7 +/- 1.7 mmHg and 1.92 +/- 0.06 mL min-1 g-1 liver, respectively. Bile volume production and HOU were maximal at 784 +/- 84 microL h-1 and 0.99 micromol/L min-1 g-1 respectively. Erythrocyte damage in the perfusate was evaluated by measurement of reduction in perfusate hematocrit from 9.75 +/- 0.35% to 9.27 +/- 0.24%, and increases in plasma free hemoglobin, which rose from 85.8 +/- 12.3 mg% to 650.1 +/- 53.3 mg% over the 6-hr perfusion period studied. Using bile volume production, hepatic oxygen uptake, and the liberation of plasma free hemoglobin as the most sensitive indices of adverse conditions, the new circuit was capable of supporting an isolated perfused rat liver for periods of up to 6 hr under close-to-physiological conditions.

Animals↗
PubMed1994

Synthesis of lactoferrin and casein by explants of bovine mammary tissue.

Synthesis of lactoferrin and casein by the bovine mammary gland was determined in an experimental model where lactation was maintained in one mammary half, while involution was induced in the contralateral half. Culture of explants with prolactin had no consistent effect on synthesis of casein or lactoferrin in tissue from either mammary half. Endotoxin and tumor necrosis factor-alpha generally decreased synthesis of casein and lactoferrin, suggesting that these inflammatory mediators are not directly responsible for increasing lactoferrin synthesis during mammary inflammation or involution. Synthesis of lactoferrin was increased and casein decreased in the involuting mammary half vs. the lactating half. These results suggest that local factors in the mammary gland play a role in the regulation of lactoferrin synthesis during involution.

Animals↗
PubMed1994

Effect of coexposure to asbestos and kerosene soot on pulmonary drug-metabolizing enzyme system.

This article reports the effect of coexposure to Indian chrysotile asbestos (5 mg/rat) and kerosene soot (5 mg/rat) on the pulmonary phase I and phase II drug-metabolizing enzymes 1, 4, 8, 16, 30, 90, and 150 days after a single intratracheal inoculation. Exposure to soot resulted in a significant induction of the pulmonary microsomal cytochrome P450 and the activity of dependent monooxygenase, benzo(a)pyrene (B[a]P) hydroxylase, and epoxide hydrase at all time intervals. On the other hand, the cytosolic glutathione S-transferase (GST) activity was induced at days 1, 4, 8, 16, and 30 after exposure, followed by inhibition in the enzyme activity. In contrast, chrysotile exposure depleted cytochrome P450, B[a]P hydroxylase, epoxide hydrase, and GST at initial stages, while all these parameters except GST were induced at later stages. However, coexposure to chrysotile and soot led to a significant inhibition in the cytochrome P450 levels, activities of B[a]P hydroxylase, epoxide hydrase, and GST at initial stages of exposure. At advanced stages, however, an additional increase in cytochrome P450, B[a]P hydroxylase, and epoxide hydrase but a decrease in GST was observed. These results clearly show that the intratracheal coexposure to high levels of asbestos and kerosene soot alters the metabolic activity of the lung, which is turn may retain toxins in the system for a longer period, resulting in adverse pathological disorders.

Animals↗
PubMed1994

Two-dimensional electrophoretic analysis of proteins of bovine mammary gland secretions collected during the dry period.

Proteins in mammary gland secretions, collected from Holstein cows during the dry period, were analyzed by preparative isoelectric focusing, followed by SDS-PAGE. Protein profiles changed throughout the dry period. Intact casein bands were present throughout the dry period, but in reduced proportions from d 7 after dry-off through d 7 prepartum. Breakdown fragments of casein were particularly apparent in secretions from d 7 to 21 of the dry period. A fragment of beta-CN (approximately 13 kDa) was identified in secretions collected on d -1 prior to dry-off through d 21 of the dry period. beta-Lactoglobulin generally focused in a limited number of fractions, but, in the sample at d 21 prepartum, beta-LG focused over a broad pH range. Lactoferrin was found in all fractions after isoelectric focusing, but specific degradation products of lactoferrin were apparent only at certain times during the dry period. This method is a valuable approach for separation of proteins from the complex mixtures found in mammary secretions during the dry period. A number of peptides identified by this method may be generated from breakdown of milk proteins in the mammary gland during the dry period and could have a role in the involuting gland.

Amino Acid Sequence↗
PubMed1994

Natural sodium sesquicarbonate fed for an entire lactation: influence on performance and acid-base status of dairy cows.

Forty-eight multiparous Holstein cows were blocked according to month of parturition, age, and previous milk yield and arranged in a randomized complete block design to evaluate the effect of a naturally occurring sodium sesquicarbonate on DMI, milk yield, milk composition, milk value, and systemic acid-base status. Cows were assigned at parturition to diets containing sorghum silage, alfalfa hay, concentrate, and 0 or 1% naturally occurring sodium sesquicarbonate (DM basis); cows were fed these diets for 308 d postpartum. Blood was collected every 4 wk via jugular venipuncture for analysis of pH, HCO3, partial pressure of O2, and partial pressure of CO2. Sesquicarbonate exhibited alkalogenic properties by increasing blood HCO3, partial pressure of CO2, and total CO2 for the 308-d lactation. Buffer tended to increase DMI and increased milk protein throughout lactation. During 0 to 56 d postpartum, sodium sesquicarbonate did not affect milk yield or composition. In midlactation (56 to 252 d postpartum), buffer increased milk protein content only. During 252 to 308 d postpartum, milk fat and protein contents increased with buffer supplementation. Hence, the value of milk yielded daily was similar for all cows. Effects of dietary buffer on all variables were more pronounced during late lactation.

Acid-Base Equilibrium↗
PubMed1993

Cytotoxic and genotoxic effects of calcium silicates on human lymphocytes in vitro.

Calcium silicate has been considered as a possible replacement for asbestos due to its heat and fire resistance. We describe the cytotoxic and genotoxic potential of calcium silicate using peripheral human blood lymphocytes. Calcium silicates at concentrations of 10 and 100 micrograms/ml significantly increased the frequencies of chromosomal aberrations (CAs) and sister-chromatid exchanges (SCEs). The increases in CAs and SCEs were dose-dependent, though not linearly. A significant decrease in the proliferation rate index was observed with increased dose of calcium silicates. The induction of chromatid-type aberrations indicates that the clastogenic activity of calcium silicate is S-phase-dependent.

Adult↗
PubMed1993

Controlled ruminal infusion of sodium bicarbonate. 3. Influence of infusion dose on systemic acid-base status, minerals, and ruminal milieu.

Four ruminally cannulated, lactating Holstein cows were assigned to a 4 x 4 Latin square to monitor effects of intraruminal NaHCO3 infusion on temporal changes in ruminal and systemic acid-base status and mineral metabolism. Twice daily from 2 to 4 h postfeeding, cows were infused with 0, 110, 220, or 330 g of NaHCO3 dissolved in 3.8 L of water. All cows had access to their TMR of sorghum silage and concentrate (35: 65, DM basis) for 2 h twice daily. Ruminal fluid, blood, and urine were collected at feeding and every 30 min postfeeding for 12 h on the last day of each 14-d period. Total urine volume also was measured during this interval. Infusion of buffer increased ruminal fluid buffering capacity transiently at 4.5 h postfeeding but otherwise did not markedly affect ruminal fluid acid-base status. Systemic acid-base status was unaffected by the buffer primarily because renal excretion of base successfully reduced systemic base load. Urine volume increased in response to NaHCO3 infusion. Buffer infusion increased urinary excretion of Na, Mg, and K but decreased Ca excretion for 12 h postfeeding; Cl excretion was not affected. Buffer infusion tended to increase total VFA in ruminal fluid. Our data indicate that homeostatic mechanisms can eliminate exogenous base via the kidneys; hence, acid-base status was not perturbed by infusion of NaHCO3. The increased excretion of Mg and K with buffer infusion indicates that the dietary requirements for these minerals may be increased by NaHCO3. Although loss of Ca through the urine was reduced by buffer infusion, this reduction may indicate reduced availability of Ca to the cow. The diuresis accompanying large doses of NaHCO3 may increase dietary requirements for some minerals.

Acid-Base Equilibrium↗
PubMed1993

Ultrasonographic diagnosis of hepatobiliary ascariasis.

Eight cases of hepatobiliary invasion of Ascaris lumbricoides into the hepatobiliary tract are presented. In the presence of nonspecific symptoms and biochemical test results, the diagnosis was made in seven patients by sonography. In the remaining patient, in whom the adult roundworm was not visible on sonography owing to the presence of aerobilia, the diagnosis was made at ERCP. Sonography revealed typical tubular, echogenic, filling defects along the long axis of a dilated common bile duct, sometimes exhibiting slow movements and containing a central sonolucent line. Repeated sonographic examinations accurately predicted treatment success.

Adult↗
PubMed1993

[Therapy by endoscopic laser for prostatic obstruction].

As part of the search for alternatives to transurethral resection of the prostate (TURP) attention has (re)turned to laser methods. We describe our experience with the currently available endoscopic beam deflection devices, particularly the Prolase II. 25 patients, generally with medical reasons to avoid TURP, and with proven bladder outlet obstruction (BOO) due to benign prostatic enlargement (BPH) underwent prostatic laser coagulation. Average age was 72 years (range 57-84), mean prostatic size by transrectal ultrasound (TRUS) was 48 g (15-100), average pretreatment peak flow rate (FR) was 7.6 ml/s (4.56-12.4). All patients were markedly symptomatic. Patients underwent clinical examination, Prostate specific antigen assay (PSA = 3.75, range 0.1-10.2), and TRUS preoperatively to exclude prostate cancer. After cystoscopic assessment the prostate was lasered according to the device manufacturers recommendations and clinical experience. A suprapubic catheter (SPC) and urethral catheters were inserted, the urethral for 24 hours. If voiding was satisfactory the SPC was removed after 24-48 hrs. Alternatively the patient was discharged and assessed at weekly intervals for SPC removal. Mean duration of SPC drainage was 11 days. Total mean impatient stay was 4.5 days (2-13) during a mean of 2 admissions. Blood loss was minimal and there were no other significant complications. At a minimum follow up of 3 months mean peak FR was 15.3 ml/s (9-31). Symptom scores (IPSS) fell from a mean of 21 to 10 by 3 months after treatment. There was an initial period of irritability for up to 12 weeks but symptomatic improvement was noted in all.

Aged↗
PubMed1993

Desirability of using buprenorphine and diazepam as an adjunct to atropine in patients undergoing fibreoptic bronchoscopy.

This study endeavours to evaluate the need for sedation in fibreoptic bronchoscopy and response of the patients when sedation is not used. One hundred and five patients divided into three groups of 35 patients each, received buprenorphine (0.3 mg), diazepam (10 mg) and normal saline (0.5 ml) respectively along with atropine (0.6 mg) in each case. The study emphasizes that sympathetic explanation of the details of the procedure to the patients, administration of careful topical anaesthesia and avoidance of sedation makes the procedure acceptable, safe, comfortable with less complications and the need for admitting the patients to the ward is by and large avoided.

Administration, Topical↗
PubMed1992

Induction of chromosomal aberrations in bone marrow cells of asbestotic rats.

In the present study, cytogenetic effects of Indian chrysotile asbestos in rat bone marrow cells after 290 days of intratracheal inoculation (5 mg dust/0.5 ml normal saline), when it develops massive pulmonary fibrosis, were investigated. The pulmonary fibrosis was confirmed by both histopathological studies and increased collagen content in the lung of the treated animals. In the asbestotic rats a significant increase in chromosomal aberrations was recorded and a decrease in mitotic index of bone marrow cells. The types of chromosomal aberrations in these cells were chromatid gaps and breaks. The results indicate the significant cytogenetic changes in the bone marrow cells of asbestotic rats and also suggest that these changes directly or indirectly may be one of the biological events involved in eliciting the asbestos-mediated toxic responses.

Animals↗
PubMed1992

Diminution in kerosene-mediated induction of drug metabolizing enzymes by asbestos in rat lungs.

In order to determine the pulmonary toxicity of kerosene and its ignition product (soot) in asbestos exposed subjects, the activities of phase I and phase II drug metabolizing enzymes in rat lungs after single intratracheal co-exposure to Indian chrysotile asbestos and kerosene or its soot and Indian chrysotile were assayed. Exposure to kerosene or its soot resulted in a significant increase in the level of microsomal cytochrome P-450 and the activity of P-450 dependent monooxygenase, benzo(a)pyrene hydroxylase, as well as in the activities of microsomal epoxide hydrase and cytosolic glutathione-S-transferase (GST). However, in chrysotile exposed animals a reverse pattern in these parameters was recorded. The co-exposure to chrysotile and kerosene or chrysotile and soot led to a significant depletion in cytochrome P-450 level and a decrease in the activities of benzo(a)pyrene hydroxylase, epoxide hydrase and GST when compared to kerosene and soot controls, respectively. These results suggest that asbestos by altering the pulmonary drug metabolizing enzyme system may increase the toxic potential of kerosene and its ignition product in the respiratory system.

Animals↗
PubMed1992

Influence of dietary cation-anion balance during the dry period on the occurrence of parturient paresis in cows fed excess calcium.

Our objective was to evaluate the effectiveness of a low dietary cation-anion balance (DCAB) in preventing milk fever and udder edema in dry cows consuming a high-Ca diet and to evaluate the effect of this diet on calves delivered by these cows. Seventy primiparous or multiparous cows and 50 pregnant heifers were offered alfalfa hay-based diets beginning 4 wk before their projected calving date. Diets contained 1.6% Ca and a DCAB of -3 or +9 mEq/100 g of diet DM. Blood and urine samples were collected weekly from 3 wk prepartum until 3 wk postpartum. Blood samples were collected from calves at parturition and weekly thereafter for 3 wk. Feeding a low vs high DCAB in a high-Ca diet for 3 wk prepartum did not reduce the incidence of milk fever; this lack of response may have been attributable to the relatively low DCAB of each diet and the small difference in DCAB between the two diets. Udder edema seemed to regress more rapidly postpartum for cows that had consumed the low DCAB during the dry period. Test diets fed to prepartum cows did not affect systemic acid-base status or plasma mineral content of their calves, although plasma Ca was somewhat lower for calves from cows consuming a low DCAB and was higher for calves from primigravid cows. Correlations of plasma mineral concentration of the cows with those of their calves were highest for plasma Ca (r = .75; P less than .001). We conclude that the prophylactic effects on the occurrence of milk fever of feeding a low DCAB during the dry period may be absent when diets contain greater than 1.6% Ca and DCAB is greater than or equal to -3. The cation-anion balance of the diet consumed by dry cows did not affect the acid-based status or plasma mineral content of their calves.

Acid-Base Equilibrium↗
PubMed1992

A buffer value index to evaluate effects of buffers on ruminal milieu in cows fed high or low concentrate, silage, or hay diets.

Our objective was to develop a buffer value index that would incorporate alterations in both ruminal fluid pH and buffering capacity as indicators of the influence of dietary buffering and alkalinizing agents on ruminal acid-base status. This index was evaluated using ruminal fluid from four lactating Holstein cows fed either sorghum silage or alfalfa hay in high or low concentrate diets. Ruminal fluid was incubated in vitro for 1, 2, 3, 4, or 5 h with no buffer or with 7.1 g of either NaHCO3, sodium sesquicarbonate, or a multielement buffer added per liter of ruminal fluid. Ruminal fluid pH was lower for diets based on high concentrate or alfalfa; buffering capacity between pH 5 and 7 was greater for high concentrate diets but was not affected by forage type. Ruminal fluid pH was higher for sesquicarbonate than for NaHCO3, the multielement buffer, or the control; however, ruminal fluid H+ concentration was similar between sesquicarbonate and NaHCO3, and both were lower than for the multielement buffer. Hydrogen ion concentration for the multielement buffer was lower than for the control. Buffering capacity was highest for NaHCO3, followed by sesquicarbonate, the multielement buffer, and the control. The buffer value index, which accounted for alterations in both H+ concentration and buffering capacity, was highest for NaCHO3, followed by sesquicarbonate, the multielement buffer, and the control. The poor response to the multielement buffer may be attributable to our relatively short incubation interval (less than 5 h). Dietary buffers increase both ruminal fluid pH and buffering capacity; both of these responses are beneficial.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1992

Evaluation of a system for rating edema in dairy cattle.

Our objective was to evaluate a subjective edema rating system to quantitate edema severity. Edema was evaluated with 20 nulliparous Holstein heifers from 3 wk before their expected calving date until 3 wk postpartum. Severity of udder edema was evaluated independently daily by five people throughout the 68-d experiment; a 10-point rating system (0 = no edema, 10 = severe edema) was used. One of the people developing the scoring system served as the official scorer. The accuracy of the rating system, defined as the closeness of test evaluator scores to official scores, was highest for scores 2 to 8. The precision of the system, identified by the standard error of the mean, was similar for each score in the rating system. The largest disagreement between official and test evaluator scores was evident postpartum. The large number of defined points in this rating system and the similarity between official and test scores in this study indicate the usefulness of this tool to evaluate precisely the severity of edema in dairy cattle.

Animals↗
PubMed1992

Influence of calcium chloride fed prepartum on severity of edema and lactational performance of dairy heifers.

Twenty Holstein heifers in a completely randomized design were used to evaluate the effects of prepartum dietary CaCl2 on the development and regression of edema and on subsequent lactational performance. Heifers were assigned to diets containing either 2.17% limestone or 1.5% CaCl2 (DM basis) at 3 wk before expected calving date. Except for the Ca sources, diets were identical. Test diets were only fed prepartum; at calving, all heifers were offered a lactation diet for 3 wk. Severity of edema was evaluated independently by five people daily throughout the experiment; a 10-point rating system was utilized to quantify the severity of edema. Calcium chloride reduced the severity of edema, although this response was most evident during the 1st wk that this salt was fed. The beneficial effects of CaCl2 on edema prepartum disappeared postpartum, when CaCl2 was removed from the diet. Indeed, edema was higher for heifers fed CaCl2 than for those fed limestone at 2 wk postpartum. Calcium chloride reduced DMI prepartum, but, following parturition, a compensatory increase in feed intake occurred. Postpartum daily DMI averaged 1.3 kg higher for heifers fed CaCl2 than for those fed the limestone diet prepartum. Milk yield and composition were somewhat lower for heifers fed CaCl2, although this response was most evident at 1 wk postpartum. Feeding CaCl2 prepartum to prevent milk fever also may reduce the severity of udder edema prepartum and increase feed intake during early lactation.

Animals↗