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Biomedical subjects

T Yao

Publications and source records attributed to T Yao.

At least 361 records · Page 20Linked to original sources
PubMed1982

The effect of stimulating somatic afferents on cholera secretion in the rat small intestine.

The effect on rate of cholera secretion in the small bowel of activation of the group III and A delta afferent fibres in the sciatic nerve was studied in rats. Activation of these fibres at 3 Hz for 60 min significantly diminished choleraic secretion from 121 +/- 29 to 25 +/- 9 microliters x min-1 x 100 cm-2 serosal surface (mean +/- SE; n = 9). The effect was apparent after the nerve stimulation. Stimulation of the sciatic nerve had no significant effect on choleraic fluid secretion after interrupting the autonomic nerves to the intestine, nor did it significantly alter net fluid transport in non-choleraic intestine with intact nervous supply. It is proposed that the observations may explain the clinical reports of an effect of acupuncture on cholera secretion.

Afferent Pathways↗
PubMed1982

Bile acid absorption kinetics in Crohn's disease on elemental diet after oral administration of a stable-isotope tracer with chenodeoxycholic-11, 12-d2 acid.

A non-radioactive tracer, deuterium, incorporated in chenodeoxycholic acid, was used to study bile acid absorption kinetics employing gas chromatography-mass fragmentography for its analysis. Eight patients with Crohn's disease and four control volunteers were administered chenodeoxycholic-11, 12-d2 acid. In order to obtain constant dietary conditions, they were fed by an elemental diet during the study. There were significant reductions of the biological half-life of chenodeoxycholic-11, 12-d2 acid, the pool size of chenodeoxycholic acid, and the total bile acid pool size in patients with Crohn's disease as compared with those in normal subjects. There was a marked increase in the relative concentration of ursodeoxycholic acid with a concomitant decrease of deoxycholic acid in patients with Crohn's disease, although such differences did not reach statistical significance. The present study confirms that there are some impairments of enterohepatic circulation of bile acids in patients with Crohn's disease.

Adolescent↗
PubMed1981

Hypercapnia and hypoxia: chemoreceptor-mediated control of locus coeruleus neurons and splanchnic, sympathetic nerves.

Utilizing single cell recording techniques to study brain norepinephrine (NE) neurons in the locus coeruleus (LC) and, in the same rats, registration of splanchnic nerve activity (SNA) the effects on these systems of hypercapnia and hypoxia, respectively, were studied. Hypercapnia (pCO2 36-103 mm Hg) caused a rapid increase in the firing rate of LC neurons as well as in SNA. This effect was directly correlated with the added amount of CO2 in the inspired gas mixture. This finding indicates a similar chemo-receptor-mediated regulation of LC neurons and SNA. Since deafferentation of peripheral chemoreceptors did not alter the response of these systems to hypercapnia, the chemoreceptors involved must be centrally located. In hypoxia (pO2 105-31 mm Hg) the overall effect on LC neurons was activation, whereas SNA was reduced. These effects were, however, not dose-dependent. Peripheral receptor deafferentation abolished the activation by hypoxia, suggesting that the LC neurons are influenced also by peripheral chemoreceptors. The results indicate that the previously observed increase in brain NE turnover in hypercapnia is largely secondary to increased neuronal activity and not due to, e.g., changes in metabolic enzymes. In addition, the data implicate chemoreceptors, centrally but also peripherally located, in the regulation of brain NE neurons in the LC. The activation of these neurons in hypercapnia, generally associated with increased apprehension in man, is consistent with the notion that the LC may serve as an alarm system in the brain.

Animals↗
PubMed1981

Endoscopic features of adenoma of the duodenal papilla in familial polyposis of the colon.

The duodenal papillae of 24 patients with familial polyposis of the colon were examined in detail by duodenofiberscopy and endoscopic biopsy. Adenomas were detected in 12 of the 24 patients (50%). Endoscopically the duodenal papilla had a white nodular or granular surface in most of the patients in whom adenoma was detected. In two patients, however, the endoscopic picture of the adenoma at the duodenal papilla was almost normal. Based on these observations, endoscopy and biopsy of the duodenal papilla should be added to the usual examination done in patients with this disease.

Adenoma↗
PubMed1981

An unusual case of localized multiple peptic ulcer of the gastric fundus producing a large exophytic fibrous pseudotumor.

We report an unusual case of fundic ulcer of the stomach, suspected radiologically of being an intramural malignant tumor. Grossly the lesion was a protruding large fibrous pseudotumor, reminiscent of fibromatosis or of a granuloma with secondary ulceration. Microscopical examination revealed that it was an unusually voluminous fibrosis produced in the base of long-standing multiple peptic ulcers in a limited area of the gastric fundus. The fundic gland area is a rare site of peptic ulceration, and the occurrence of such an exophytic tumor-forming type of peptic ulcer in this area even rarer, only one relevant case having been reported before.

Female↗
PubMed1981

Renal nerve activity and exaggerated natriuresis in conscious spontaneously hypertensive rats.

Exaggerated natriuresis upon volume loading occurs in both human and animal hypertension and is mainly due to suppressed tubular reabsorption. To explore whether altered renal sympathetic activity contributes to this response, conscious male spontaneously hypertensive rats (SHR) were exposed to isotonic saline loading in comparison with normotensive male Wistar Kyoto rats (WKR). After a 60 min control hydropenic period, during which mean arterial pressure, heart rate, renal sympathetic nerve activity and urinary sodium excretion were followed, a 60 min period of intravenous volume expansion with isotonic saline (0.2 ml/min X 100 g b.w.) was started followed by a 60 min hydropenic recovery period. Already during the control period sodium excretion was significantly higher in SHR. During the volume load and subsequent recovery period a clearly exaggerated natriuresis occurred in SHR compared with WKR. Further, volume loading reduced renal sympathetic nerve activity in all animals, but significantly more in SHR. Moreover, volume loading reduced mean arterial pressure and heart rate in both groups. It is suggested that the accentuated reflex inhibition of renal sympathetic activity in SHR upon volume loading emanates from cardiac mechanoreceptors and partly explains the exaggerated natriuresis in SHR. This augmented "volume' reflex response is probably due to reduced systemic venous compliance in SHR with a consequently increased central filling and cardiac receptor activation.

Animals↗
PubMed1981

Peripheral and central vascular compliances in conscious normotensive and spontaneously hypertensive rats.

Changes of left atrial (LAP) and right atrial pressure (RAP) upon 10% and 20% blood volume expansion were studied in conscious spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKR) with intact nervous cardiovascular control. In a separate series the changes of central (CBV) and peripheral (PBV) blood volumes upon similar increases of total blood volume (TBV) were measured as well, throughout using male, adult SHR and WKR in both series. During volume expansion both LAP and RAP increased significantly more in SHR than in WKR, as did CBV, while PBV increased significantly less in SHR than in WKR. Total "effective' vascular compliance, defined as delta TBV/delta RAP, was significantly lower in SHR. From the two series of measurements central (CBV/LAP) and peripheral (PBV/RAP) vascular compliances could be separately deduced. Central vascular compliance was nearly 50% lower in SHR than in WKR. However, "unstressed' volume of the peripheral compartment appeared to be rather normal in SHR compared to WKR. It is therefore suggested that the decreased total vascular compliance seen in essential hypertension and in SHR is mainly due to a decreased distensibility of the systemic capacitance vessels.

Animals↗
PubMed1981

Correlation between decreased heart rate and central inhibition of sympathetic discharge after prazosin administration in the spontaneously hypertensive rat.

Mean arterial blood pressure, heart rate and splanchnic sympathetic discharge were recorded in conscious and anaesthetized spontaneously hypertensive rats (SHR). Administration of prazosin (1 mg/kg i.v.) reduced heart rate in most rats and this effect was closely parallelled by a decrease in sympathetic discharge. In contrast, administration of hydralazine (1 mg/kg i.v.) caused a sustained tachycardia and increased sympathetic nervous activity. The cardiovascular effects of prazosin (0.2-0.3, 1 and 3 mg/kg i.v.) were examined in different rat strains. Sprague-Dawley and Wistar-Kyoto rats responded with tachycardia whereas a significant bradycardia was observed in SHR following the higher doses of prazosin. It is suggested that the bradycardia obtained after prazosin administration is due to a central inhibition of sympathetic outflow, an effect possibly caused by blockade of alpha-adrenoreceptors. The different heart rate responses in different rat strains may be interpreted to reflect differences in sensitivity of central alpha-adrenoreceptors.

Animals↗
PubMed1980

Distensibility of the left atrial wall in spontaneously hypertensive rats compared with that in normotensive Wistar-Kyoto rats.

1. The cardiac mechanoreceptors, which in rats are mainly located in the left atrial wall, are reset in spontaneously hypertensive rats. The atrial pressure has to be almost twice as high in spontaneously hypertensive rats as in normotensive controls to produce similar receptors activations, as is apparent from previous studies. 2. The present study was performed to investigate whether this resetting is due to decreased distensibility of left atrial walls in the spontaneously hypertensive rats. 3. Static load-length relationships were investigated in vitro on left atrial strips, and pressure-volume relationships were studied on isolated left atria from spontaneously hypertensive and normotensive Wistar-Kyoto rats. 4. The force per cross-sectional area exerted during a relative length increase of 80% was significantly greater in spontaneously hypertensive rats. The dynamic but not in the static distensibility was significantly lower in these animals. 5. The decreased dynamic distensibility of left atrial walls in spontaneously hypertensive rats can at least partly explain the resetting of atrial receptor function.

Animals↗
PubMed1980

Diagnostic value of intraoperative fiberscopy for small-intestinal polyps in familial adenomatosis coli.

X-ray examination and intraoperative fiberscopy of the small intestine were performed in 20 patients with familial adenomatosis coli. Roentgenographic study detected polypoid lesions in the upper jejunum in 2 patients (10%), and in the terminal ileum in 9 (45%). In contrast, endoscopic study revealed polyps in the jejunum in 10 patients (50%), and in the ileum in 14 (70%). Polyps in most cases were multiple and small in size (less than 3 mm in diameter). Histology revealed the lesions of the jejunum to be adenomas, and those of the ileum to be lymphoid hyperplasia with or without adenoma. The present study suggests that intraoperative endoscopy is much more valuable than roentgenography in detecting these minute polyps of the small intestine in this disease.

Adolescent↗
PubMed1980

Distensibility of left atrium in normotensive and spontaneously hypertensive rats.

In spontaneously hypertensive rats (SHR) left atrial mechanoreceptors are reset. Thus, left atrial pressure must be almost twice as high in SHR as in normotensive rats to produce comparable degrees of receptor activation and reflex sympathetic inhibition. The present study was performed to investigate whether this resetting is due to a decreased atrial distensibility in SHR. Static load-length relationships were therefore investigated on isolated left atrial strips from 11 pairs of male SHR and Wistar Kyoto rats (WKR). After each experiment the strips were fixed at a passive tension of 4 mN and the average wall thickness was determined histologically. Furthermore, pressure-volume relationships were studied on non-beating, isolated left atria from SHR and WKR. Distensibility was here defined as % volume increase when LAP was increased from 2.5 to 12.5 mmHg either rapidly (0.5--1 s, "dynamic" distension) or slowly (3 min, "static" distension). Atrial wall thickness did not differ significantly in SHR and WKR, but the passive force (mN) per cross sectional area exerted during elongation above 80% was greater (P less than 0.05) in SHR. Also the "dynamic", but not the "static" volume distensibility was significantly lower in SHR (P less than 0.01). The decreased dynamic distensibility of SHR left atrial walls can at least partly explain the resetting of the atrial receptors activated during the rapid filling phase.

Animals↗
PubMed1980

Spontaneous disappearance of fundic gland polyposis: report of three cases.

Three cases are reported in which multiple sessile polyps of the stomach disappeared spontaneously during the follow-up period from 9 to 34 mo. All of the patients were middle-aged females, and the distribution of the polyps was limited to the portion of the stomach with fundic glands. Histolgoic examination revealed simple hyperplasia of the fundic glands with microcysts. The macroscopic and histologic pictures were the same as the gastric lesions ("fundic gland polyposis") found in cases with familial adenomatosis coli; however, colonic polyposis was not observed in our cases. The possible cause of the spontaneous disappearance of the polyps was discussed.

Adult↗
PubMed1979

Turcot's syndrome and its mode of inheritance.

Two sisters with Turcot's syndrome, in which malignant cerebral neoplasms are associated with colonic polyposis, are presented. Cases reported in the literature, including some familial cases, have also been analysed. In familial cases, sex was unrelated to the occurrence of this disease and it was found only among siblings of the same parents and not in other members of the family. There was consanguinity in the parents of the patients in two out of three families. We therefore concluded that the mode of inheritance in this condition is autosomal recessive and that it is genetically distinct from the ordinary form of familial polyposis coli. Support is lent to the absence of an association between the two disorders by a difference in the number, size, and distribution of the colonic polyps found in Turcot's syndrome as compared with familial polyposis coli.

Adenoma↗
PubMed1978

Gastric lesions in familial adenomatosis coli: their incidence and histologic analysis.

In order to detect accompanying gastric lesions, we examined 22 patients with familial adenomatosis of the colon belonging to 14 families. Various gastric lesions were confirmed in 15 patients (68.2 per cent) belonging to 13 families. The lesions were found histologically to be adenoma in nine cases, fundic gland polyposis in six, carcinoma in three, and microcarcinoid in two. Fundic gland polyposis consisting of simple hyperplasia of the fundic glands seems to be the gastric lesion specific to familial adenomatosis of the colon and rectum. Familial adenomatosis coli not only affects the colon and rectum, but is also capable of inducing tumorigenicity in other organs. The stomach is one of the organs in which extracolonic lesions occur.

Adenocarcinoma↗