Ultrastructural studies of endocrine-like cells in the fundic gastric mucosa of the bullfrog,Rana catesbeiana

Summary This study is concerned with electron-microscopic observations on endocrine or paracrine cells in the fundic gastric mucosa of the bullfrog. Also, an attempt was made to identify the histamine-releasing cells involved in the secretagogue response. At least three distinct endocrine-like cell types were found. The classification is based on the appearance of secretory granules and other organelles, and the relationship of endocrine-like cells with other cells in the tissue. The amphibian endocrine-like cells resemble the ECL, D and EC cells of mammals. Type-I (ECL) cells showed degranulation after repeated stimulation with tetragastrin (TG), acetylcholine (ACh) and K⁺ depolarizing solution, all of which release histamine.     

The influence of limb alignment and transfemoral amputation technique on muscle capacity during gait

Many factors influence successful outcomes following transfemoral amputation. One factor is surgical technique. In this study, the influence of limb alignment and surgical technique on a muscle’s capacity to generate force was examined using musculoskeletal modeling. Non-amputee and transfemoral amputee models were analyzed while hip adduction, femur length, and reattached muscle wrap position, tension and stabilization technique were systematically varied. With muscle tension preserved, wrap position and femur length had little influence on muscle capacity. However, limb alignment, muscle tension and stabilization technique notably influenced muscle capacity. Overall, myodesis stabilization provided greater muscle balance and function than myoplasty stabilization.     

Autofluorescence imaging for recurrence detection in skin cancer postoperative scars

This clinical study is a first attempt to use autofluorescence for recurrence diagnosis of skin cancer in postoperative scars. The proposed diagnostic parameter is based on a reduction in scar autofluorescence, evaluated in the green spectral channel. The validity of the method has been tested on 110 postoperative scars from 56 patients suspected of non‐melanoma skin cancer, with eight patients (13 scars) available for the repeated examination. The recurrence diagnosis within a scar has been made after two subsequent autofluorescence check‐ups, representing the temporal difference between the scar autofluorescence amplitudes as a vector. The recognition of recurrence has been discussed to represent the significant deviations from the value of vector angle θ. This new autofluorescence‐based method can be easily integrated into the postoperative monitoring of surgical scars and can help diagnose the recurrence of skin cancer from the early stage of scar development.     

Gastric emptying and serum insulin levels after intake of glucose-polymer solutions

To examine the gastric emptying characteristics of four drinks varying in carbohydrate composition and concentration, five men ingested 600 ml of one of the different drinks on four separate occasions. All drinks contained Na+ 71 mmol.l-1, Cl- 60 mmol.l-1, Mg+2 5 mmol.l-1 and citrate 7 mmol.l-1; the carbohydrate component was either 3% glucose, 3% glucose-polymer (GP), 5% GP or 10% GP. With 99mTc-diethylene-triaminepenta-acetic acid (DTPA) as a marker, a scintillation camera and computer were used to measure the rate of gastric emptying. The half-emptying times (T 1/2) were inversely related to the glucose content of the solutions. The T 1/2 for 3% PG was 22.4 +/- 4.4 min (mean +/- SE) and for 10% GP 50 +/- 3.3 min (p less than 0.005). There was no significant difference in T 1/2 between the 3% glucose and 3% GP solutions. The increments in blood glucose (highest blood levels from 7.4 +/- 0.3 mmol.l-1 to 8.9 +/- 0.8 mmol.l-1), serum insulin (from 28 +/- 6 mU.l-1 to 77 +/- 13 mU.l-1) and C-peptide (from 3.6 +/- 0.4 micrograms.l-1 to 5.8 +/- 0.9 micrograms.l-1) were related to the amount of carbohydrate ingested. In all cases the serum insulin levels were high enough to inhibit the liberation of free fatty acids from the adipose tissue. It is concluded that the amount of carbohydrate in glucosyl units in the solution is a major determinant of gastric emptying.(ABSTRACT TRUNCATED AT 250 WORDS)     

Glomerular bypass shunts in the kidney of the Atlantic hagfish,Myxine glutinosa

Summary The vascular pathways associated with the glomerulus of the Atlantic hagfish, Myxine glutinosa have been studied by scanning electron microscopy of corroded resin casts of the vasculature. Although the overall pattern of the renal vasculature did not differ from earlier reports, a previously unreported vascular pathway which arose from the renal artery and bypassed the glomerular capillaries in 28% of glomeruli was clearly demonstrated. Glomerular bypass shunts either ran to join the loose capillary network around Bowman's capsule and thereby drain into the network of vessels associated with the mesonephric duct (ureter), or ran directly into the ureteral system of vessels and subsequently into the posterior cardinal veins. Glomerular bypass shunts which theoretically permit renal arterial blood to bypass the process of filtration may play a role in the regulation of body fluid volume.     

Species-specific effects of bombesin on gastric emptying and neurohypophyseal secretion

Previous reports have demonstrated that systemic injection of cholecystokinin (CCK) in rats produces dose-related decreases in food intake, increases in neurohypophyseal secretion of oxytocin (OT), and decreases in gastric emptying. The present studies determined whether systemic injection of bombesin (BBS), another peptide that potently reduces food intake in rats, had similar effects on OT secretion and gastric emptying. Although BBS produces a dose-dependent inhibition of food intake, even very high doses did not significantly affect plasma OT levels and only slightly decreased rates of gastric emptying. Consequently, despite their similar inhibitory effects on food intake, BBS does not appear to activate the same network of central nervous system pathways as does CCK in rats. However, parallel studies in monkeys demonstrated that systemic injection of BBS was effective in stimulating neurohypophyseal secretion of vasopressin rather than OT, in a pattern both qualitatively and quantitatively analogous to the effects of CCK in this species. Together with previous findings that BBS more potently inhibits gastric emptying in primates than in rats, these results therefore also suggest the presence of significant species differences in the central mechanisms by which BBS acts to reduce food intake.     

Glomerular bypass shunts and distribution of glomeruli in the kidney of the lesser spotted dogfish,Scyliorhinus caniculus

Summary Scanning electron microscopy of corroded resin casts of the renal vasculature of Scyliorhinus caniculus has revealed a novel vascular pathway arising from the afferent arteriole and bypassing the glomerulus. This glomerulus bypass shunt occurred in 36% of the glomerular casts examined. The shunt ran to join a peritubular network of capillaries and thereby offers the potential to vary the degree of glomerular perfusion and control the proportion of active glomeruli. In 29% of glomeruli two efferent arterioles drained the capillary knot. Glomeruli were located close to the dorsal margin of the posterior mass of the kidney, and towards the lateral edge of the anterior lobes of the kidney of female dogfish. In male dogfish, glomeruli were evenly distributed through the posterior mass of kidney, while in female dogfish 89% of glomeruli occurred in the posterior mass and 11% of glomeruli were located within the small anterior lobes.     

Oxygen-derived free radicals and hemolysis during open heart surgery

Reperfusion injury occurs during open-heart surgery after prolonged cardioplegic arrest. Cardiopulmonary bypass also is known to cause hemolysis. Since reperfusion of ischemic myocardium is associated with the generation of oxygen free radicals, and since free radicals can attack a protein molecule, it seems reasonable to assume that hemolysis might be the consequence of free radical attack on hemoglobin protein. The results of this study demonstrated that reperfusion following ischemic arrest caused an increase in free hemoglobin and free heme concentrations, simultaneously releasing free iron and generating hydroxyl radicals. In vitro studies using pure hemoglobin indicated that superoxide anion generated by the action of xanthine oxidase on xanthine could release iron from the heme ring and cause deoxygenation of oxyhemoglobin into ferrihemoglobin. This study further demonstrated that before the release of iron from the heme nucleus, oxyhemoglobin underwent deoxygenation to ferrihemoglobin. The released iron can catalyze the Fenton reaction, leading to the formation of cytotoxic hydroxyl radical (OH·). In fact, the formation of OH. in conjunction with hemolysis occurs during cardiac surgery, and when viewed in the light of the in vitro results, it seems likely that oxygen-derived free radicals may cause hemolysis during cardiopulmonary bypass and simultaneously release iron from the heme ring, which can catalyze the formation of OH·.     

血清胃泌素变化与急性胃粘膜病变关系的研究

对大白鼠血清中胃泌素水平的变化与急性胃粘膜病变的关系进行了初步的研究,结果表明以消炎痛为诱因引起的急性胃粘膜病变大白鼠血清胃泌素水平明显增高。而维酶素可以抑制因消炎痛引起的急性胃粘膜病变时血清胃泌素的释放,对胃粘膜具有保护作用。     

Effects of selective cholecystokinin antagonists L364,718 and L365,260 on food intake in rats

The selective type A and B cholecystokinin (CCK) receptor antagonists L364,718 and L365,260 were used to identify the receptor subtype that mediates the satiety effect of endogenous CCK. Male rats (n = 12–13/group), fed ground rat chow ad lib, received L364,718 (0, 1, 10, 100, or 1000 μg/kg IP) or L365,260 (0, 0.1, 1, 10, 100, 1000, or 10,000 μg/kg IP) 2 h after lights off, and food intake was measured 1.5, 3.5, and 5.5 h later. L364,718 significantly stimulated 1.5-h food intake by more than 40% at 10 μg/kg and higher doses; cumulative intake at 3.5 and 5.5 h remained elevated by about 20% at 1000 and 100 μg/kg of L364,718, respectively. In contrast, L365,260 had no significant stimulatory effect on feeding at any dose. The potency of L365,260 for antagonizing gastrin-stimulated gastric acid secretion was examined in unanesthetized rats. Male rats (n = 14), prepared with gastric and jugular vein cannulas, received doubling doses of gastrin (G-17I) (0.16–5 nmol/kg/h IV), each dose for 30 min, and gastric juice was collected for each 30-min period. G-17I stimulated gastric acid output dose dependently; the minimal effective dose was 0.16 nmol/kg/h, while maximal output (5-fold above basal) occurred at 5 nmol/kg/h. L365,260 (0, 1, 10, 100, 1000, or 10,000 μg/kg IV), administered 30 min before continuous infusion of G-17I (1.25 or 5 nmol/kg/h), significantly inhibited acid output only at 10,000 μg/kg; cumulative 60-min output was decreased by 60%. These results suggest that CCK acts at CCK-A receptors to produce satiety during the dark period in ad lib-feeding rats.