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Biomedical subjects

R Ahmad

Publications and source records attributed to R Ahmad.

177 records · Page 10Linked to original sources
PubMed1976

Production and diagnostic application of anti-human T-cell antisera.

This paper is intended to demonstrate the extension of experimental procedures used for the production of anti-chicken T-cell sera to the manufacturing of anti-human T-cell sera. Specific anti-chicken bursa (ABS) and anti-chicken thymus cell sera (ATS) were prepared in turkeys. The in vitro specificity of these sera was assessed by means of immunofluorescence and lymphocytotoxicity tests. The selective immunosuppressive effect of ABS was demonstrated in Obese strain (OS) chickens with spontaneous autoimmune thyroiditis, that of ATS in a skin allograft system. A specific anti-human T-cell serum was prepared by immunizing a horse with fetal human thymus cells. After appropriate exhaustive absorptions this serum was found to react specifically with human T-cells. An anti-T cell globulin (ATG) fraction prepared from the absorbed antiserum was then labelled with FITC for use in direct immunofluorescence tests. The potential diagnostic value of T-cell specific antibodies is discussed.

Animals↗
PubMedDate not supplied

Autism in fragile X females.

We present two women with the fragile X syndrome (Martin-Bell syndrome) and autism. Both are mentally retarded, one mildly and one severely. Cytogenetic studies showed a high percentage of lymphocytes with the fragile X chromosome and inactivation occurring preferentially in the normal X chromosome. Autism is shown to be a severe behavioral and cognitive manifestation of the fragile X syndrome in females.

Adult↗
PubMedDate not supplied

Necrotising fasciitis in the head and neck region.

Necrotising fasciitis is an uncommon entity in present day medicine. Our review of the literature did not reveal any case involving the head and neck region. A case of this rare disease involving the head and neck region is presented.

Facial Dermatoses↗
PubMedDate not supplied

Bladder tumours in paraplegic patients on renal replacement therapy.

Fourteen adult patients with end-stage renal disease due to spina bifida or spinal-cord injury underwent regular haemodialysis for 3-120 (mean 20) months. Seven of these patients received renal transplants. Urinary bladder tumours developed in four of the fourteen patients (three squamous-cell carcinoma in patients stil on dialysis, one poorly differentiated transitional-cell carcinoma in a patient after successful transplantation). All four had widespread metastatic disease and died within 8 weeks of the diagnosis of cancer. We recommend regular urological evaluation for patients with neurogenic bladder even after initiation of dialysis treatment. Total cystectomy before transplantation might greatly reduce the risk of these rare tumours.

Adult↗
PubMedDate not supplied

Cardiovascular interactions of local anesthetics and calcium entry blockers in conscious dogs.

To assess the pharmacologic risk of regional anesthesia in patients treated with calcium entry blockers (CEBs), the cardiovascular effects of 30-minute infusions of lidocaine (60 micrograms.kg-1.minute-1 after an intravenous bolus of 1.5 mg.kg-1), bupivacaine (15 micrograms.kg-1) or normal saline (1 ml.minute-1) were studied with concurrent 40-minute infusions of equihypotensive doses of verapamil (25 micrograms.kg-1.minute-1) and diltiazem (20 micrograms.kg-1.minute-1) in seven conscious dogs chronically instrumented for continuous recording of arterial pressure and left ventricular (LV) contractility assessed by the peak of LV dP/dt. The effects of CEBs alone (saline group) were stable throughout the infusion time. Besides a 10% decrease in mean arterial pressure, verapamil increased heart rate, prolonged atrioventricular (AV) conduction and decreased LV dP/dt, whereas a lesser and isolated tachycardia was observed in the case of diltiazem. At the end of a 30-minute concomitant infusion: (1) bupivacaine (1.4 micrograms/ml) further decreased arterial pressure (with verapamil and diltiazem; -8% and -11%, respectively) and LV dP/dt (with verapamil, -13%), whereas PR interval was further lengthened with verapamil and diltiazem (+36% and +17%, respectively) without change in heart rate; (2) lidocaine (approximately 3.5 micrograms/ml) increased heart rate (with verapamil and diltiazem; +19% and +14%, respectively) and arterial pressure (with verapamil, +8%) without change in LV dP/dt, while the PR interval was further lengthened during verapamil infusion (+34%). Second-degree AV blocks appeared with lidocaine (one of seven dogs) and bupivacaine (three of seven dogs) during verapamil infusion. Caution should therefore be exercised when patients under effective verapamil or diltiazem treatment are given regional anesthesia resulting in significant plasma levels of local anesthetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Mercury release from amalgam: a study in vitro and in vivo.

Total mercury release from a high-copper and a low-copper amalgam was measured in a study in vitro using atomic absorption spectrophotometry. Conditions of mechanical agitation and sealant coverage were evaluated over time. Mercury release was found under agitation and no-agitation conditions to increase shortly after preparation and then to level off after 24 to 48 hours. No difference in mercury release was observed for either amalgam type. Sealant coverage of amalgam significantly reduced mercury release under agitation conditions. In an experiment in vivo mercury vapor was measured at different times for patients receiving their first amalgam restoration. Sealant coverage was found to significantly reduce mercury vapor after chewing on this restoration compared to a nonsealant-covered amalgam.

Adolescent↗
PubMedDate not supplied

Interaction of intravenous diazepam and bupivacaine in conscious dogs.

The cardiac and hemodynamic effects of bupivacaine, diazepam and their coadministration were evaluated in six mongrel dogs chronically instrumented for recording of mean arterial pressure (MAP), left ventricular (LV) pressure, and cardiac output (CO, electromagnetic flow probe around the ascending aorta). LVdP/dt was derived from the LV pressure signal, and its positive peak was used as an index of myocardial contractility. Heart rate (HR), RR, PR and QT intervals were measured from ECG. At weekly intervals, each dog received in a random order one of the following treatments: (1) saline as control, (2) diazepam (0.2 mg/kg, intravenous, bolus), (3) bupivacaine (0.4 mg/kg intravenous bolus, followed by 15 micrograms/kg/minute, during 30 minutes), and (4) a combination of diazepam and bupivacaine, as in (2) and (3), respectively. Despite its intrinsic cardiodepressant effects, bupivacaine induced a delayed (30-minute) compensatory increase in HR (+ 11%, p less than 0.05) and LVdP/dt (+ 10%, p less than 0.05). Diazepam decreased systemic vascular resistance (SVR; -16%, p less than 0.05) with concomitant increases in HR and CO. After diazepam pretreatment, LVdP/dt did not rise after bupivacaine administration, whereas SVR decreased (-14%, p less than 0.05) and HR increased (+19%, p less than 0.05). The QT-RR relationship remained unchanged regardless of the treatment administered. Thus, diazepam might blunt the compensatory effects of bupivacaine on cardiac function and may decrease the margin of safety of this local anesthetic agent during major neural blockade procedure.

Animals↗
PubMedDate not supplied

Comparison of bioimpedance and Doppler ultrasound cardiac output in CAPD patients.

The reproducibility and reliability of cardiac output (CO) measurement by transthoracic electrical bioimpedance (TEB) and dual beam Doppler ultrasound methods were compared in 9 uremic patients during treatment with continuous ambulatory peritoneal dialysis (CAPD). CO was measured simultaneously by each method during supine rest and 70 degree passive head-up tilt on two separate days. The effect on CO after the infusion of dialysate was also studied on day 1. CO, stroke volume (SV) and heart rate (HR) measurements were reproducible by each method. The median day to day differences (95% confidence intervals) in CO and SV were 0.6 (-0.3, 1.8) l/min and 10 (-1.5, 24.5) ml for TEB and 0.7 (-0.5, 2.2) l/min and 13 (-1.0, 30.5) ml for Doppler at supine rest; 0.4 (-0.2, 0.9) l/min and 11 (-0.5, 19.0) ml for TEB and 0.5 (-0.3, 1.2) l/min and 8 (-5.0, 16.0) ml for Doppler during tilt (p > 0.05 in each case). Data were unobtainable by TEB at five time points while none were lost by Doppler. This is due to incorrect HR or poor quality signals detected by TEB. CO and SV measured by Doppler were higher than that by TEB during supine rest (p < or = 0.01) but not during passive tilt. As a result, there was significant change (p < or = 0.01) in CO and SV from supine to tilt measured by Doppler but not by TEB. Neither TEB nor Doppler detected significant change (p > 0.05) in CO or SV after the infusion of dialysate, in either the supine or tilt positions.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗