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Biomedical subjects

T Khalil

Publications and source records attributed to T Khalil.

36 records · Page 2Linked to original sources
PubMed1989

Release of neurotensin by selective perfusion of the jejunum with oleic acid in dogs.

Plasma neurotensin concentrations are rapidly elevated after oral ingestion or intraduodenal infusion of fat, apparently before fat reaches the ileum where neurotensin is highly concentrated. The purpose of this study was to investigate the site of neurotensin release and to determine whether neurotensin is released by direct luminal stimulation by fat in conscious dogs. Dogs were prepared with isolated jejunal or ileal segments and portal vein catheters. Release of neurotensin into the portal venous blood was examined by selective perfusion of each intestinal segment with sodium oleáte. The results of this study show that selective perfusion of the jejunum, but not the ileum, with sodium oleate, caused a significant release of neurotensin. We speculate that release of ileal neurotensin is not due to direct luminal stimulation, but is mediated by local neural or humoral intermediates.

Animals↗
PubMed1988

Effect of aging on gastric acid secretion, serum gastrin, and antral gastrin content in rats.

The purpose of this study was to characterize the effects of aging on gastric acid secretion and on serum and antral concentrations of gastrin in rats. Young and old Fischer 344 rats were prepared with gastric fistulas. Twenty-four hours after surgery, graded doses of human synthetic gastrin-17 (SHG-17) (2, 5, 10, 20, and 40 micrograms/kg) were given intravenously in random order. Gastric secretions were collected for gastric acid measurement before and at 15-min intervals after each dose of gastrin. In a separate study, blood was collected and the stomachs were removed for antral gastrin extraction from fed young and old rats. Serum and antral gastrin was measured by radioimmunoassay. The basal and gastrin-stimulated acid secretions were significantly decreased in aged rats compared to the young rats. The basal acid output was 0.4 +/- 0.2 microeq/15 min in the aged rats and 1.5 +/- 0.5 microeq/15 min in the young. The maximal acid output stimulated by gastrin was 11.1 +/- 1.8 microeq/15 min in the aged rats and 24.2 +/- 2.8 microeq/15 min in the young. Both serum and antral concentrations of gastrin were significantly decreased in aged rats. Serum gastrin concentration was 114.8 +/- 7.4 pg/ml in the aged rats and 192.0 +/- 14.4 pg/ml in the young. Antral gastrin concentration was 3.9 +/- 0.5 micrograms/g tissue in the aged rats, which was significantly less than the concentration in the young (6.5 +/- 0.4 micrograms/g tissue). Antral gastrin content did not change with aging.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1986

Neurotensin stimulates pancreatic exocrine secretion in rats.

Neurotensin (NT) stimulates pancreatic exocrine secretion in dogs and humans. The purpose of this study was to examine the effect of exogenous neurotensin on pancreatic exocrine secretion in rats. Five Sprague-Dawley male rats were prepared with pancreatic, gastric and duodenal fistulas. Bile was shunted into the duodenum in order to collect pure pancreatic juice. 24 h later, neurotensin (0.05, 0.1, 0.2, 0.3, 1.0 nmol/kg) was infused intravenously in a random fashion. Pancreatic juice was collected every 10 min, and the volume was recorded and protein and bicarbonate were measured. Neurotensin stimulated, in a dose-related manner, the pancreatic secretion of water, protein and bicarbonate. Neurotensin may be involved in the physiologic control of pancreatic secretion in rats.

Animals↗
PubMed1986

Cerebral atrophy: a schistosomiasis manifestation?

Preliminary studies with sonography indicated that a reduced brain mantle index and dilated ventricles were frequently seen in patients with chronic Schistosoma mansoni infection. Computerized tomography (CT) was used to confirm our earlier observations and to obtain more accurate measures. Brain scans of 25 patients with chronic S. mansoni infection showed mild to moderate degrees of cortical atrophy in 9 cases (36%) and central atrophy in 3 (12%). The remaining 16 subjects and 10 controls showed normal brain scans. The present study is the first report documented by CT showing a significant correlation between chronic S. mansoni infection and cerebral atrophy.

Adolescent↗
PubMed1985

Effect of aging on pancreatic secretion in rats.

We have characterized the effects of aging on the pancreatic exocrine secretory response to the normal stimulatory hormones, secretin, and cholecystokinin. Young (6 month old) and aged (26 months old) male Sprague-Dawley rats were prepared with pancreatic fistulas and challenged with different doses of secretin (0.03, 0.06, and 0.12 nmol/kg) and cholecystokinin-8 (0.3, 0.6, and 1.2 nmol/kg) intravenously. The pancreatic secretion was measured for volume and bicarbonate and protein outputs. Our results show that in aged rats, the basal pancreatic secretion volume and protein and bicarbonate outputs were significantly reduced, and the pancreatic secretion volume and protein and bicarbonate responses to graded doses of secretin or cholecystokinin-8 were significantly reduced. This study demonstrates that pancreatic exocrine function in rats diminishes with age.

Aging↗
PubMed1985

The role of neurotensin in human gallbladder motility.

Gallbladder contraction in response to a fatty meal is thought to be caused by release of cholecystokinin (CCK). We have previously demonstrated a close correlation between circulating concentrations of CCK and contraction of the gallbladder in normal humans and in gallstone patients. Recent studies in animals, however, have shown that other potentially cholecystokinetic hormonal agents are released by a fatty meal, which suggests that other hormones may be involved in postprandial gallbladder contraction. Neurotensin, a 13-amino acid peptide, is released by fat; we have shown it to cause gallbladder contraction in dogs. In the present study, we measured release of neurotensin in seven normal adult volunteers. We determined the effects of infused neurotensin (4 pmol/kg-min) on gallbladder contractility, measured by ultrasonography in 10 adult volunteers, and we evaluated release of neurotensin in eight patients with gallstones. After ingestion of fat, we found significant release of neurotensin in normal volunteers from a mean basal concentration of 15.9 +/- 3.5 pg/ml to a maximum of 34.7 +/- 0.2 pg/ml. In the gallstone patients after fat ingestion, neurotensin rose from a basal of 16.8 +/- 3.1 pg/ml to a maximum of 53.4 +/- 28.1 pg/ml, which was a significantly greater release than in controls. Intravenous infusion of neurotensin produced dilatation of the gallbladder (from a mean basal volume of 13.7 +/- 2.3 cc to 20.0 +/- 1.8 cc). Neurotensin causes relaxation of the gallbladder in humans and, by contributing to stasis, may be involved in the formation of gallstones.

Adult↗
PubMed1985

Gastrin receptors in normal and malignant gastrointestinal mucosa: age-associated changes.

Synthetic human gastrin 17-I (MG) and an analogue, [Leu15]gastrin-17-I (LG), were radiolabeled with Na125I by Iodo-Gen, EnzymoBead, and chloramine-T methods, and the characteristics of the radiolabeled peptides were determined. When 125I-MG was iodinated by chloramine-T, its biological activity and its binding activity were almost abolished, whereas the biological activity of 125I-LG, iodinated by either of the methods, and of 125I-MG, iodinated by Iodo-Gen and EnzymoBeads, was not significantly affected. The kinetics, affinity, and specificity of binding of 125I-MG, iodinated by Iodo-Gen, to crude and purified membranes from rat fundic mucosa were examined and found to be similar to that for 125I-LG. Age-associated changes in the number and affinity of gastrin receptors (GR) on the crude membranes of gastrointestinal mucosa of rats was also examined. Significantly fewer GR were observed on the crude membranes of fundic mucosa of aged (24 mo old) compared with young (3- and 6-mo-old) rats. In addition, specific gastrin-binding sites (4.7 +/- 0.9 fmol/mg prot) with low affinity (Kd = 3.7 +/- 1.2 nM) were observed in the antrum of aged rats, the significance of which is not understood. There were, however, no differences in the number and characteristics of GR in other regions of the intestine of old and young rats. The presence of GR was additionally assessed in cell lines of gastrointestinal cancers from humans, mice, and hamsters.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1985

Effect of aging on gallbladder contraction and release of cholecystokinin-33 in humans.

The objective of this study was to examine the effect of aging on gallbladder contraction and cholecystokinin (CCK) release, as well as on the correlation between the two in humans who are free of gallbladder disease. Twenty-nine human volunteers were divided into a young group of 14 individuals (ages 22 to 42 years, median age 32 years) and an older group of 15 individuals (ages 60 to 84 years, median age 66 years). In the study each person in both groups was given corn oil (Lipomul), 1.5 ml/kg, by mouth after an overnight fast. Blood was collected for measurement of CCK-33 by radioimmunoassay before and at intervals after ingestion of Lipomul. Simultaneous measurements of gallbladder volume were obtained by real-time varian ultrasonography. Both fasting and fat-stimulated concentrations of CCK in plasma were significantly higher in the older individuals than in the younger volunteers. The 60-minute integrated measurement of CCK release was significantly increased in the older people as compared with the young. Both fasting and maximally contracted gallbladder volumes were equal in the older and younger groups. The rate of emptying of the gallbladder was equal in both age groups, but the gallbladders of older people appeared to show an earlier initiation of contraction. The highly significant correlation of gallbladder contraction with levels of CCK was similar in both age groups, but the sensitivity of the gallbladder to CCK in the older people was significantly decreased. In conclusion, both fasting and fat-stimulated plasma levels of CCK increase with aging. The sensitivity of the gallbladder muscle to stimulation by CCK is diminished with age, but this appears, teleologically, to be matched by the increased release of CCK, so the kinetics of gallbladder emptying are little different in the aged.

Adult↗
PubMed1980

Plasma levels of ACTH and cortisol in bilharzial and non-bilharzial individuals during halothane and nitrous oxide anaesthesia.

The effect of stress of anaesthesia and surgery was studied in non-bilharzial and bilharzial individuals. Estimation of ACTH and cortisol was carried out by the radio-immunoassay (RIA) technique. The level of ACTH and cortisol was found to be lower in unanaesthetized bilharzial subjects than in normal individuals. Under the effect of anaesthesia and surgery the elevation in the level of both hormones was also lower in bilharzial than in non-bilharzial patients. The response to the stress of anaesthesia and surgery was more marked during halothane than during nitrous oxide anaesthesia.

11-Hydroxycorticosteroids↗
PubMed1976

Volvulus of the sigmoid in Khartoum, Sudan.

Twenty-six cases of acute volvulus of the sigmoid in Khartoum Hospital are analysed. The condition accounts for 17.8 percent of all cases of acute intestinal obstruction. The majority of patients were from the Southern tribes whose diet contains a large amount of fibre. Of the different methods of surgical management simple operative detorsion and deflation gave the best results. The overall mortality rate was 23.1 percent.

Colon, Sigmoid↗
PubMed1976

Pattern of intestinal obstruction in Khartoum.

We operated on 138 patients for intestinal obstruction. The different causes are discussed and their pattern of occurrence is compared with that reported from England and other African countries. The 27.6% mortality rate was closely associated with the 28.2% incidence of gangrene. Factors which may lower this high mortality rate are enumerated.

Adolescent↗
PubMedDate not supplied

Design of thoracolumbosacral orthosis (TLSO) braces using CT/MR.

The field of orthotics has gained scientific attention over the last few years. Its objective is to correct, adjust, or modify the operation of human limbs, joints, or muscles. Thoracolumbosacral orthosis (TLSO) braces are used by scoliosis and postoperative patients who need back correction and/or support. The anatomic dimensions for TLSO braces have been acquired mainly by casting the patient. Casting is a time-proven method for obtaining surface geometry, but it can be inconvenient in certain situations. For example, casting might not be suitable for postoperative and trauma patients owing to the risk of further injury. Such prohibitive cases can still be handled safely by X-ray CT or MR scanning. This article presents an alternative method for data acquisition of TLSO patients' anatomic dimensions using CT/MRI. The experimental results show the method to be statistically accurate, efficient, and feasible compared with the conventional casting method.

Computer-Aided Design↗
PubMedDate not supplied

[Kaposi's sarcoma. A vascular neoplasm of presumably viral origin. Histologic and ultrastructural characteristics].

Kaposi's sarcoma is a multiform mesenchymal neoplasm of uncertain histogenesis but of possible viral origin. Several anatomo-clinical forms have been described the cutaneous nodular lesion being the most common and at highest frequency in equatorial Africa. Eighteen of such typical lesions were reported; their morphology was uniform and associated: 1) spindle cells, 2) an excess of vascular spaces composed of intratumoral intercellular slits and of intra and peritumoral well structured vessels, 3) a lymphoplasmocytic inflammatory infiltration. The lesions of the other and less common forms of Kaposi's sarcoma associated the same histological features in variable combination. At one end of the histological spectrum the lesions are essentially composed of irregular capillaries with few spindle cells, at the other end the tumor is a highly cellular neoplasm with few or no angiogenic features. The vascular structure of the typical lesions appeared clearly at the ultrastructural level. Most tumor cells were of endothelial type and formed cylinders with virtual or large central lumina, reminiscing of vascular sprouts. Pericyte-like cells were also present. In one the three ultrastructurally investigated cases, a tumor cell of the endothelial type contained intranuclear herpes virus like inclusions, group to which belongs the cytomegalovirus (CMV), a possible promoter of Kaposi's sarcoma.

Adolescent↗