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Biomedical subjects

A Rahim

Publications and source records attributed to A Rahim.

At least 37 records · Page 2Linked to original sources
PubMed1998

The effect of body composition on hexarelin-induced growth hormone release in normal elderly subjects.

OBJECTIVE: Growth hormone (GH) release is influenced by several factors including age, gender, physical exercise, nutritional status, sex steroids and body composition. The relationship with body composition is complex. Obesity is accompanied by suppression of spontaneous and stimulated GH release. As increasing body fat reduces stimulated GH secretion following a standard provocative test, the potential clinical uses of GH-releasing peptides (GHRPs), therapeutically or diagnostically, may be dependent on the relationship between body fat and GHRP-stimulated GH release. We have therefore assessed the effect of body composition and gender on the GH releasing capacity of hexarelin. DESIGN: A single bolus of subcutaneous hexarelin at a dose of 1.5 micrograms per kg of body weight was administered at time 0. Blood samples were taken at -10, 0, 10, 20, 30, 40, 50, 60, 90, 120, 170 and 180 min. SUBJECTS: Twenty-one (eight male) healthy elderly subjects with a median (range) age of 68 (60-81) years and BMI of 26 (19-30) kg/m2 were studied. METHODS: Dual-energy X-ray absorptiometry (DEXA) was used to assess body composition. RESULTS: Peak GH response correlated negatively with fat mass, BMI, percentage body fat, and weight [r = -0.72, P = 0.0001; r = -0.56, P = 0.009; r = -0.63, P = 0.002 and r = -0.48, P = 0.029, respectively,]. AUC GH correlated negatively with fat mass, BMI and percentage fat mass [r = -0.58, P = 0.006; r = -0.51, P = 0.019 and r = -0.66, P = 0.001 respectively]. Using multiple linear regression, fat mass was the most useful predictor for both peak GH response [R2 = 0.61, P < 0.0001] and AUC GH [R2 = 0.38, P = 0.003]. Gender was not a significant variable. CONCLUSIONS: Increasing total fat mass results in a blunted GH response following subcutaneous hexarelin. Total fat mass appears to be a useful predictor of peak GH response even in normal individuals as none of the subjects in the present study was morbidly obese. This indicates that there is a continuum of effect of fat mass on hexarelin-stimulated GH release. Any impact of gender on the GH response to hexarelin is almost certainly indirect and mediated via differences in body composition. This observation will have an impact on the potential diagnostic and therapeutic uses of hexarelin and related GH secretagogues.

Aged↗
PubMed1998

Growth hormone status during long-term hexarelin therapy.

Hexarelin, a powerful GH-releasing peptide, is capable of causing profound GH release in normal subjects after oral, intranasal, i.v., and s.c. administration. The effect of long-term administration on GH levels in adults is unknown. We have, therefore, assessed the effects of 16 weeks of twice-daily s.c. hexarelin therapy (1.5 micrograms/kg BW) on the GH response to a single injection of hexarelin, and also the GH response to hexarelin 4 weeks after cessation of hexarelin therapy. We have also assessed the effects of chronic hexarelin therapy on serum insulin-like growth factor (IGF)-I, IGF binding protein-3, markers of bone formation (osteocalcin, procollagen-type-III-N-terminal-peptide, and C-terminal propeptide of type I collagen), and resorption (urinary deoxypyridinoline and pyridinoline), body composition, and bone mineral density. The mean (+/- SEM) area under the GH curve (AUCGH) at weeks 0, 1, 4, 16, and 20 were 19.1 +/- 2.4 micrograms/L.h, 13.1 +/- 2.3 micrograms/L.h, 12.3 +/- 2.4 micrograms/L.h, 10.5 +/- 1.8 micrograms/L.h, and 19.4 +/- 3.7 micrograms/L.h, respectively. There was a significant change in AUCGH over the study period (P = 0.0003). Further analysis showed that, compared with baseline, the decrease in AUCGH at week 4 and week 16 were significant (P < 0.05 and P < 0.01, respectively). Four weeks after completion of hexarelin therapy, the AUCGH increased significantly, compared with AUCGH at week 16 (P < 0.05), and was not significantly different from that at week 0. Serum IGF-I and IGF binding protein-3 did not change significantly over the 20-week period (P = 0.24 and P = 0.74, respectively). Of the bone markers measured, only serum C-terminal propeptide of type I collagen changed significantly and was higher at week 16, compared with baseline (P = 0.019). Total body fat, lean body mass, and bone mineral density had not changed significantly at week 16, compared with baseline (P = 0.6, P = 0.3, and P = 0.3, respectively). In summary, we have demonstrated that chronic hexarelin therapy results in a partial and reversible attenuation of the GH response to hexarelin. In the present study, the biological impact of this hexarelin schedule on the GH-IGF-I axis seems to be minimal. The therapeutic potential of chronic hexarelin requires further investigation.

Aged↗
PubMed1998

Intercostal muscles in the rabbit: surgical anatomy and flap construction.

Demos and colleagues (1967) obtained good antireflux results from transposing an intercostal myoneurovascular pedicle around the gastro-oesophageal junction in dogs. An intact neurovascular supply is essential for the viability of a muscle flap. The aim of this study was to delineate the nerve and arterial supply to the left 11th intercostal muscle in the rabbit and to assess whether this muscle could be mobilized as a viable flap. The innervation of the muscle was studied using the methods of gross dissection in cadaveric specimens, and histological staining techniques. The arterial supply was studied using gross dissection, and aortography. In three non-recovery experiments, intercostal muscle was transposed around the gastro-oesophageal junction. The distal motor latency was recorded after electrical stimulation of the intercostal wraps. Gross dissection, histological staining techniques, and aortography showed that the left 11th intercostal muscle group in the rabbit is supplied by segmental vein, artery and nerve, running between external and internal intercostal muscles. Aortography and electrical stimulation demonstrated that the muscle group could be mobilized with an intact neurovascular supply. The left 11th intercostal muscle group has potential as a viable muscle flap for use in surgical procedures within the upper abdomen.

Animals↗
PubMed1998

Incidence of carcinoma of the oral cavity in Karachi--district south.

Globally oral cancer is one of the ten common cancers. In some parts of the world, including the Indian sub-continent oral cancer is a major problem. The two year data of the Karachi Cancer Registry, showed oral cancer was the second most common malignancy in the males as well as in the females. The most common malignancy amongst the males being the carcinoma of the lungs and amongst the females, carcinoma of the breast. The annual incidence rate of oral cancer was 4.1 per 100,000 annually for the males and 4.0 per 100,000 annually for the females.

Adolescent↗
PubMed1996

The assessment of growth hormone status in normal young adult males using a variety of provocative agents.

OBJECTIVE: In adults, there are few data regarding GH responses to provocative stimuli other than insulin-induced hypoglycaemia. We have compared the GH response to four different growth hormone secretagogues and placebo in normal healthy adult males. DESIGN: This was a prospective, randomized, placebo-controlled study in 18 normal male subjects. After an overnight last, an intravenous cannula was inserted into the arm of each subject and a blood sample was taken for GH at -30, -15, and 0 minutes. Four provocative agents (intravenous insulin 0.2 IU/kg; intravenous arginine 20 g/m2 as an infusion over 30 minutes; oral clonidine, either 100 or 200 micrograms; intramuscular glucagon 1 mg) and placebo were administered to each subject in a randomized manner on different days. Further blood samples were taken at 15-minute intervals for 180 minutes for GH estimation. RESULTS: The median (range) GH peak response for each agent was insulin 107.7 (28.1-200) mU/l; arginine 22.3 (3.1-72.9) mU/l; glucagon 42 (11.8-200) mU/l; 100 micrograms clonidine 7.2 (< 1-22.2) mU/l; 200 micrograms clonidine 8.2 (1.1- 88) mU/l and placebo 2.4 (< 1-30.2) mU/l. The peak GH response to insulin-induced hypoglycaemia (ITT) was significantly greater than for any other agent (P < 0.0001). The peak GH response to glucagon was significantly greater than for arginine (P < 0.05), clonidine at 100 and 200 micrograms (P < 0.01) and placebo (P < 0.01). The peak GH response following administration of arginine was significantly greater than for clonidine 100 and 200 micrograms (P < 0.05), and placebo (P < 0.01). The peak GH response following clonidine 200 micrograms was not significantly greater than following clonidine 100 micrograms (P = 0.38) or placebo. On an individual basis two, six and 15 of 18 subjects failed to achieve a peak GH level of > 20 mU/l to glucagon, arginine and clonidine respectively. In complete contrast only one subject achieved a peak response of less than 40 mU/l (28.1 mU/l) to ITT. CONCLUSIONS: The most profound GH release is seen after insulin-induced hypoglycaemia. Glucagon appears to be more effective at inducing GH release than arginine. Clonidine at a dose of 100 or 200 micrograms is no more effective than placebo.

Adult↗
PubMed1996

The prevalence of severe growth hormone deficiency in adults who received growth hormone replacement in childhood [see comment].

OBJECTIVE: The few previous studies in which reassessment of GH status has been carried out in young adults treated with GH therapy for childhood GH deficiency concentrated on determining the incidence of 'transient GH deficiency'. As the benefits of GH replacement therapy in adults become increasingly appreciated, it is likely that GH therapy started in childhood for GH deficiency will be continued into adult life in many of those with severe GH deficiency. The aim of this study is to determine how many patients who received GH replacement therapy in childhood until completion of growth have GH deficiency severe enough to be considered for GH replacement therapy in adult life. DESIGN: Retrospective analysis of the peak GH responses to provocative stimuli performed at the time of diagnosis of GH deficiency in childhood and at the completion of growth after GH replacement therapy had been stopped. PATIENTS: Eighty-eight adults (49 male, 39 female) who had received GH therapy in childhood for a diagnosis of GH deficiency. The aetiology of the GH deficiency included craniopharyngioma, radiation induced associated with either a cerebral tumour or acute lymphoblastic leukaemia, histiocytosis-X and idiopathic. MEASUREMENTS: In childhood the original diagnosis of GH deficiency was based biochemically on the failure of the peak GH response to reach 20 mU/l during two provocative tests in 59 of the 88 patients and to a single test in the remaining 29. A total of 147 tests were performed, the most common being an insulin tolerance test (ITT, n = 72) and an arginine stimulation test (AST, n = 53). At reassessment in young adult life 146 tests were performed (74 ITT, 64 AST). Severe GH deficiency was defined arbitrarily as a peak GH response of less than 9 mU/l to a single (n = 33) or to two (n = 55) pharmacological stimuli. RESULTS: By definition all patients were considered GH deficient at the time of initial diagnosis. A peak GH response of less than 9 mU/l was seen in 64.8% at initial assessment and 60.2% at reassessment. Analysis in aetiological terms, however, showed that between assessments the incidence of severe GH deficiency increased in the group of radiation induced (48.8 vs. 55.8%) but decreased in the idiopathic group (78.1 vs. 53.1%). Out of the 55 patients who underwent two tests at reassessment, 47.3% of those with a GH peak less than 9 mU/l at one test had a GH peak greater than 9 mU/l at the second test. Fifteen of the 55 patients had additional pituitary hormone deficiencies and all 15 had a GH peak below 9 mU/l in both tests. CONCLUSIONS: Our study suggests that all children who have received GH replacement therapy in childhood should undergo reassessment of GH status in young adult life. Between 40 and 60% of such patients merit consideration for GH therapy in adult life depending on the definition of severe GH deficiency in use. Patients with isolated GH deficiency should undergo two provocative tests of GH secretion, but those with additional anterior pituitary hormone deficiencies require only one test at reassessment.

Adolescent↗
PubMed1995

The anatomic basis for arteriovenous shunting in human lower leg fascial flaps.

Clinical experience has suggested that arteriovenous shunting may occur in fascial flaps. The anatomic basis for this has not been fully established. The aim of this study was to determine the size, location, and nature of arteriovenous shunts in human lower leg deep fascia. Deep fascia was harvested from the limbs of nine embalmed cadavers. Small pieces of fascial tissue were studied with the aid of three staining techniques (methylene blue, oil red-O triethyl phosphate, and Gomori's rapid one-stage trichrome technique), which were used to enable the microvascular anatomy to be visualized more clearly. Arteriovenous anastomoses proximal to the capillary bed and with an external diameter greater than 50 microns were identified in the suprafascial, subfascial, and intrafascial plexuses but were not found to be a common feature of the microvascular anatomy. Thoroughfare channels within the capillary bed and with an external diameter ranging from 12 to 25 microns were frequently identified in all three levels of the fascial plexus. The results of this study establish an anatomic basis for arteriovenous shunting in fascial flaps.

Arteriovenous Anastomosis↗
PubMed1993

Emerging patterns of child-spacing in Canada.

This study used data from the 1984 Family History Survey conducted by Statistics Canada to examine recent trends and patterns of child-spacing among currently married women. Life table and proportional hazards estimates show that Canadian women, particularly those in younger age groups with higher education and longer work experience, start having children late, but have subsequent children rather quickly. This suggests that such women tend to complete childbearing within a compressed time period.

Adolescent↗
PubMed1992

Normalization of impaired response of platelets to prostaglandin E1/I2 and synthesis of prostacyclin by insulin in unstable angina pectoris and in acute myocardial infarction.

The minimal inhibitory concentration of prostaglandin E1 (used as a probe for prostacyclin [PGI2]) needed to inhibit platelet aggregation (36 +/- 16 nM) in normal volunteers (n = 40) increased (64 +/- 30 nM) in patients (n = 46) with acute coronary artery disease. Bolus injection of insulin in 20 patients, 0.1 U/kg body weight 4 times a day (every 6 hours) for 7 days decreased the minimal inhibitory concentration of prostaglandin E1 from 64 +/- 30 to 26 +/- 12 nM (p less than 0.001). Twenty other patients who received only saline solution had no decrease in minimal inhibitory concentration of the prostanoid. The bolus injection of insulin also increased the plasma level of PGI2 (9 +/- 2 pM) two-fold in these patients (28 +/- 10 pM). Administration of aspirin inhibited the insulin-induced increase of plasma prostanoid level. Patients in the placebo group had no increase in plasma PGI2 level. The bolus injection of insulin administered only once to another group of patients (n = 6) demonstrated that the hormonal effects were maximally increased within an hour of insulin administration, and were directly related to the increased insulin level in plasma. These results indicated the feasibility of using physiologic quantities of insulin for controlling of platelet aggregation through resensitization of platelet response to prostaglandin and increased synthesis of PGI2 in vivo in acute coronary artery disease.

Angina, Unstable↗
PubMed1991

Sex differences in performance on a combined manual and decision task.

This report describes results of an experimental study of the differences in response time between 10 male and 10 female undergraduate operators performing a combined manual and decision task. Analysis indicated that the performance times of women on such tasks were shorter than those of the men as expected.

Adult↗
PubMed1989

Ulcers produced by ligation of individual gastric mucosal arteries in the guinea pig.

It is not known whether or not individual gastric mucosal arteries are end-arteries. We therefore occluded single mucosal guinea pig arteries, resulting in necrosis of the whole thickness of mucosa in the area supplied by the artery in 25 of 33 cases (76%). However, there were no cases of necrosis in 33 control sham ligations performed in the same animals (p less than 0.001). In another group, ligation of two or three adjacent mucosal arteries resulted in necrosis in 10 of 11 cases (p less than 0.0001), against 0 necrosis in 11 sham ligations. Killing the animals at varying intervals showed that after 1 day the mucosa was necrotic, after 2 days it was shed, and later it might perforate. We conclude that many mucosal arteries in the guinea pig may behave as functional end-arteries. How these findings may pertain to ulceration is discussed in relation to (a) the existence of atypical mucosal arteries found in the ulcer-bearing areas in humans and (b) the role of the muscularis mucosae on arterioles perforating it in both humans and other species.

Animals↗
PubMed1982

Demographic variables in general job satisfaction in a hospital: a multivariate study.

The relationships between demographic variables, such as income, age, education, sex, marital status, job categories (nurses, medical technologists, pharmacists, and administrators) and general job satisfaction were studied in a community general hospital. Analysis showed that females were more satisfied than males when income, age, and education were controlled through covariance. Income and age positively affected job satisfaction when sex, marital status, and job categories were controlled through covariance.

Age Factors↗
PubMed1982

Coronary sinus pacer lead simulating left atrial mass.

M-mode and two-dimensional echocardiographic evaluation of a patient with rheumatic heart disease and an atrioventricular sequential pacemaker with a coronary sinus lead showed an echo-producing mass in the left atrium. A repeat study after the coronary sinus lead was replaced by a right atrial screw-in lead revealed the disappearance of the echo-producing mass.

Diagnosis, Differential↗
PubMed1980

Pseudo-mitral-valve echogram following prosthetic mitral valve replacement.

Echocardiographic recordings from a patient with a prosthetic mitral valve revealed echoes within the left ventricular cavity that mimicked the motion pattern of a "normal" anterior mitral leaflet. The echo pattern was continuous, recorded from multiple views, and by two-dimensional images it was localized to the level of the papillary muscles. Although thrombus and vegetation are possibilities, this echo probably originates from a pliable chordal structure severed but not removed at the time of surgery. The apparent responsiveness to hemodynamic influences was striking, and we suggest that the prevalence and pathophysiologic implications of such findings are of potential import.

Aged↗
PubMed1980

Echocardiographic observations regarding pericardial effusions associated with cardiac disease.

Cardiac disease associated with congestive heart failure was found to be the most common cause (22 of 76) of pericardial effusion in patients referred for echocardiography. Parameters of left heart function were markedly abnormal in these patients with congestive heart failure and pericardial effusion, but were not significantly different from a group of patients with congestive heart failure without pericardial effusion. Clinical findings consistent with cardiac decompensation also failed to discern between these two groups. Nonetheless, patients with congestive heart failure with pericardial effusion had significantly larger right ventricular internal dimensions than those without effusion. Patients with pericardial effusion related to congestive heart failure (P < .01), heart disease without congestive heart failure (P < 0.001) and those patients post recent myocardial infarction (P < 0.05) had significantly larger right ventricular internal dimensions in diastole than normal subjects. Patients with pericardial effusions related to recent open heart surgery, idiopathic pericarditis or of miscellaneous causes had normal right ventricular internal dimensions. It is likely that right ventricular dilation indicates abnormal volume/pressure relationships of the right heart and that this abnormality, through alterations in venous and lymphatic drainage, underlies the accumulation of pericardial effusion in these patients with heart disease with or without congestive heart failure.

Aged↗