News of risk as a potential stressor.
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Disease↗
Biomedical subjects
M Horowitz
Publications and source records attributed to M Horowitz.
Solid and liquid gastric emptying in patients with gastro-oesophageal reflux.
A dual isotope radionuclide technique has been used to assess solid and liquid gastric emptying simultaneously in 72 patients with symptomatic gastro-oesophageal reflux and 22 normal controls. Objective evidence of gastro-oesophageal reflux was obtained from standard acid reflux testing and/or endoscopy in all patients. Solid emptying was delayed in 32 patients (44 per cent), liquid emptying was delayed in 27 patients (37 per cent) and 16 of those two groups had delayed solid and liquid emptying. Thus 29 patients (40 per cent) had normal solid and liquid group (P less than 0.01). There was a significant correlation (P less than 0.01) between the solid and liquid gastric emptying values obtained in patients. No significant correlation was found between gastric emptying and the resting lower oesophageal sphincter pressure or the presence of symptoms of regurgitation and epigastric fullness. In the patients with delayed solid emptying there was a higher incidence of oesophagitis than in patients with normal emptying (P less than 0.05).
Adult↗
Acute and chronic effects of domperidone on gastric emptying in diabetic autonomic neuropathy.
Gastric emptying was studied with a double radioisotopic method in 12 patients with insulin-dependent diabetes mellitus complicated by autonomic neuropathy and in 22 control subjects. In the diabetics, the acute and chronic effects of oral domperidone on gastric emptying, symptoms of gastroparesis, and glycemic control were assessed. Gastric emptying of solid and liquid was slower in diabetics than controls (P less than 0.001). Acute administration of domperidone increased the rate of both solid and liquid emptying (P less than 0.005). Domperidone was most effective in those patients with the greatest delay in gastric emptying. After chronic administration (35-51 days), domperidone had no significant effect on solid emptying (P greater than 0.05), but was still effective in increasing liquid emptying (P less than 0.025). Symptoms of gastroparesis were less after domperidone (P less than 0.001).
Adult↗
Effects of body temperature elevation on auditory nerve-brain-stem evoked responses and EEGs in rats.
ABRs and EEGs were recorded in anaesthetized rats during whole body hyperthermia. ABR amplitudes were decreased during warming, with little recovery as body temperature was lowered. The latencies of the ABR waves decreased with warming and increased with subsequent cooling. The major latency changes were in the later ABR waves. Warming was accompanied by suppression of the EEG. These results point out that ABR evaluation of patients must take into account elevated body temperatures. Since it has been shown that the rat can serve as a model of the effects of heat on man, an attempt is made to relate these ABR and EEG findings in rats to studies of human psychomotor performance during heat exposure.
Animals↗
Redistribution of cardiac output in anesthetized thermally dehydrated rats.
Cardiac output (CO) and its distribution were studied in dehydrated (37 degrees C) anesthetized (Na thiopentone) rats prior to and following heat acclimation (at 34 degrees C), using 57Co 15 micron microspheres. In non-acclimated dehydrated rats, CO decreased while heart rate (HR) increased significantly. Following acclimation CO increased without any change in HR; during dehydration CO remained elevated together with a significant increase in HR. In non-acclimated rats at low dehydration blood perfusion to peripheral thermoregulatory areas increased while perfusion of splanchnic area decreased; at high dehydration level peripheral blood flow decreased whereas splanchnic blood flow was augmented. In acclimated dehydrated rats, CO distribution to thermoregulatory areas did not change while perfusion of the splanchnic area decreased. It is suggested that following acclimation, the increased CO contributes to maintenance of thermoregulatory peripheral blood flow; in non-acclimated rats severe dehydration leads to augmented blood flow in the permeable splanchnic vascular bed, increasing efflux of plasma protein and failure of plasma volume conservation.
Acclimatization↗
Thermoregulatory activity in the rat: effects of hypohydration, hypovolemia and hypertonicity and their interaction with short-term heat acclimation.
Hypothalamic temperature thresholds to heat-induced (40 degrees C ambient temperature) tail vasodilation (Vth) and salivation (Sth) as well as salivary flow rate and volume were studied in conscious rats, hypohydrated (24 hr water deprivation), hypovolemic (20% dextran sc), hypertonic (1M NaCL po), hypertonic and hypovolemic and heat-acclimated (5 days at 34 degrees C) before and after hypohydration. Sth was elevated in hypohydrated, hypovolemic, hypertonic and heat-acclimated hypohydrated rats concomitantly with a remarkable decrease in saliva volume, flow rate and heat tolerance. Heat acclimation alone resulted in a reduction in Vth, Sth, salivary flow and volume. Vth was not affected by hypohydration, but was elevated following hypovolemia and combined hypovolemia and hypertonicity. It is concluded that alterations in both plasma volume and osmolarity, which may occur during hypohydration, play a major role in the alteration in thermoregulatory responses during hypohydration. Heat acclimation does not improve tolerance during hypohydration. Thus, during hypohydration, the control of body fluids overrides thermoregulation.
Acclimatization↗
Altered responsiveness to parasympathetic activation of submaxillary salivary gland in the heat-acclimated rat.
Submaxillary salivary gland responsiveness during the heat acclimation procedure (34 +/- 1 degree C) was studied in the rat. Gland responsiveness was evaluated by measuring saliva flow rate of the anesthetized animals following either parasympathetic nerve stimulation or i.v. application of pilocarpine. A thirty percent decrease in glandular responsiveness for the two modes of stimulation was measured during the first 10 days of acclimation. Following 60 days of acclimation recovery was observed. It is concluded that decreased responsiveness of the heat-acclimated gland is a glandular event. Increased saliva flow occurring at the initial phase of acclimation is apparently due to changes in the thermoregulatory center.
Acclimatization↗
The effect of calcium supplements on plasma alkaline phosphatase and urinary hydroxyproline in postmenopausal women.
Although calcium supplements are widely used in the treatment of osteoporosis, their beneficial effect is not conclusively established. We now report some effects of a calcium supplement (1 g/day) given for 6 to 12 weeks to 15 postmenopausal osteoporotic women. The mean fasting urinary hydroxyproline/creatinine ratio decreased from 0.021 +/- 0.002 to 0.015 +/- 0.001 (P less than 0.0025), indicating a significant reduction in bone resorption. The mean plasma alkaline phosphatase fell from 123 +/- 5 U/l to 104 +/- 3.1 U/l (P less than 0.01), probably representing some secondary reduction in bone formation following the inhibition of bone resorption. These results support the concept that calcium supplementation is useful in the treatment of postmenopausal osteoporosis.
Aged↗
The effect of domperidone on oesophageal emptying in diabetic autonomic neuropathy.
Oesophageal emptying of solids was studied with a scintigraphic technique in 12 patients with insulin dependent diabetes complicated by autonomic neuropathy and in 22 control subjects. In the diabetics the acute and chronic effects of oral domperidone on oesophageal emptying and symptoms of heartburn and dysphagia were assessed. The number of swallows required to clear the oesophagus in the diabetics (median 9.5, range 2-30) was significantly greater (P less than 0.001) than in normal controls (median 2, range 1-14). Domperidone did not increase solid oesophageal emptying in diabetic patients either after acute or after chronic administration.
Adult↗
Fenfluramine delays gastric emptying of solid food.
The effect of a single dose of (+/-)-fenfluramine hydrochloride (40 mg) on gastric emptying of a mixed solid and liquid meal was assessed with a dual isotope scintigraphic technique in eight obese patients. Fenfluramine significantly delayed gastric emptying of solid food (approximately a 15% reduction in the solid linear emptying rate), but had no effect on gastric emptying of liquid.
Adult↗
Is the stomach a useful forensic clock?
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Forensic Medicine↗
The normal menstrual cycle has no effect on gastric emptying.
Recent studies have demonstrated that orocaecal transit time is prolonged both in the luteal phase of the ovulatory cycle in normal women and during pregnancy, but have made no attempt to differentiate between the individual effects of gastric emptying and small intestinal transit. We have assessed the effect of the normal menstrual cycle on gastric emptying of solids and liquids in 10 women, using a dual isotope scintigraphic technique. In each subject gastric emptying was measured on 2 days: first during the follicular phase (day 8-10) and then during the luteal phase (day 18-20) of one ovulatory menstrual cycle (where day 1 was the first day of menstrual bleeding). Measures of solid and liquid gastric emptying did not change significantly between the follicular and luteal phases indicating that the normal menstrual cycle has no effect on gastric emptying.
Adult↗
Altered solid and liquid gastric emptying in patients with duodenal ulcer disease.
Alteration in gastric emptying has been implicated in duodenal ulcer disease. The precise abnormalities remain controversial. We have used a radionuclide technique to assess solid and liquid gastric emptying in 14 patients with endoscopically proven duodenal ulcer and 22 healthy controls. Solid gastric emptying values for the patient group fell within the normal range. The median time taken for 50% (T50) of the liquid marker to empty from the stomach was 12 minutes (range 6-23 minutes) which was significantly faster (p less than .005) than controls (median 18 minutes, range 11-35). In 10 of the 14 patients, however, the rate of liquid emptying was within the normal range. There was no significant difference in the T50 for gastric emptying of solids between the groups, but in duodenal ulcer patients food left the stomach significantly earlier than in controls (p less than .05). After this, however, the linear rate at which duodenal ulcer patients emptied solid food from the stomach was a median 0.75%/minutes (range 0.5-1.4 minutes), which was slower (p less than .0005) than controls, median 1.25/minutes (range 0.7-2.3). These results show that the pattern of gastric emptying of digestible solids and liquids in patients with duodenal ulcer disease, as a group, is significantly altered.
Adult↗
Gastric emptying--forensic implications of current concepts.
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Australia↗
The relation between calcium absorption, serum dehydroepiandrosterone, and vertebral mineral density in postmenopausal women.
Vertebral mineral density, measured by computerized axial tomography, radiocalcium absorption, serum dehydroepiandrosterone (DHA), and serum cortisol (C) were measured in 98 postmenopausal women aged 56-70 yr. On the basis of spine radiographs and fracture history, the women were classified into 49 normal subjects (mean age, 60.5 yr) and 49 with osteoporosis (mean age, 63.1 yr). Vertebral mineral density (VMD), radiocalcium absorption (alpha), serum DHA, and the ratio of DHA to cortisol (DHA/C) were all significantly lower in the osteoporotic than in the normal subjects. DHA was significantly related to C in both groups but the regression was significantly flatter in the osteoporotic than in the normal subjects. Calcium absorption did not fall significantly with age in either group. In the normal group VMD, DHA, and DHA/C fell with age but VMD was not related to alpha, DHA, or DHA/C. In the osteoporotic group, VMD did not fall significantly with age but was significantly related to alpha and DHA/C. Stepwise regression analysis showed that in the normal subjects, age was the only variable significantly related to VMD (P less than 0.05). In the osteoporotic group, calcium absorption was the main determinant of VMD, with age and DHA/C contributing much less to the variance. Discriminant function analysis showed a theoretical misclassification of 45% of cases using DHA, 39% using DHA/C, 32% using alpha, and 18% when alpha and DHA or DHA/C were both taken into account. It is concluded that malabsorption of calcium is a significant risk factor for postmenopausal osteoporosis, probably because of a secondary increase in bone resorption to maintain serum calcium. The severity of the osteoporosis is directly related to the severity of the calcium malabsorption. Low serum DHA appears to represent a further risk factor, either because of its role as estrogen precursor or (possibly) because it promotes bone formation. However, the severity of the osteoporosis was not related to the serum DHA level and only weakly to the DHA/C ratio.
Aged↗
Subtalar dislocations: a prognosticating classification.
A review of the literature and analysis of eight cases of subtalar dislocations was undertaken to correlate our experience with others and to determine a classification for prognostication. Our findings corresponded with those found by others. A 75% incidence of associated injuries was present in our series and these represented a continuum of varying degrees of complication. A new system was devised whereby increasing severity of associated injuries correlated with increasing rate of complications, including loss of motion, arthritis, pain and avascular necrosis. Dislocations were classified according to: no associated injuries, those with soft tissue injuries, extra-articular fractures, intra-articular fractures and those prone to development of avascular necrosis, ie, open dislocations and fractures of the body of the talus. It was found that associated fractures increased the immobilization period as well as the incidence of complications. Intra-articular fractures have demonstrated increased rates of arthroses in the subtalar joint. Avascular necrosis, an infrequent but devastating complication, is primarily associated with open dislocations and dislocations with concomitant fractures of the body of the talus. Our series had two open subtalar dislocations, neither of which developed avascular necrosis.
Adolescent↗
The differential inhibitory effect of lymphotoxin and immune interferon on normal and malignant lymphoid cells.
Supernatants containing lymphotoxin (LT) and immune interferon (IFN-gamma) or IFN-gamma alone were produced by antigen-stimulated murine T cell clones. These lymphokine preparations as well as cloned recombinant murine IFN-gamma (Genentech) were tested for antiproliferative activity on a variety of murine T, B, macrophage, and mastocytoma tumors and on T cell clones and LPS-stimulated B cells. The growth of every cell line tested was susceptible to the LT-containing supernatants. Cloned recombinant murine IFN-gamma inhibited the growth of A9 fibroblasts but not L929 cells. Neither the cloned murine IFN-gamma nor that produced by a T cell clone had any appreciable effect on the lymphoid cells except for one B cell lymphoma, A20. The sensitivity of nontransformed T and B cells to LT indicates that this lymphokine may play an immunoregulatory role. Indeed, the T cells that produce LT are sensitive to its cytotoxic activity and, therefore, regulate themselves. The differential inhibitory effects of LT and IFN-gamma on lymphoid target cells allow us to distinguish between preparations that contain IFN-gamma alone and those that contain LT and IFN-gamma. The susceptibility of lymphoid tumors to the antiproliferative activity of the LT-containing preparations indicates that LT either alone or together with IFN-gamma may be useful in tumor therapy.
Animals↗
A monoclonal antibody that recognizes an Ly-6-linked antigen inhibits the generation of functionally active T cell subsets.
A monoclonal antibody (mAb) generated against the chemically-induced BALB/c Meth A sarcoma, designated HD42, reacts in cytotoxic tests with Meth A as well as with BALB/c peripheral lymph node cells and mitogen-activated spleen cells. The antigen was detected by FACS analysis on BALB/c spleen and lymph node cells, and by absorption assays on all normal lymphoid cells of BALB/c but not B6 mice. The expression of the antigen was not found on normal adult lung fibroblasts, on brain, nor on an extensive panel of tumors of BALB/c and B6 origin. Because the strain distribution of the antigen is reciprocal to that of Ly-6.2 and is not expressed in congenic C3H.Ly-6b mice, we have tentatively defined it as Ly-6.1 and referred to the mAb as alpha-Ly-6.1. The presence of alpha-Ly-6.1 abrogates both the Con A-induced and the IL 2-dependent proliferative response of normal T cells, whereas the response of normal B cells to LPS remains unaffected. alpha-Ly-6.1 is a potent suppressor of the primary in vitro plaque-forming cell (PFC) response to SRBC. Pretreatment of normal splenic T cells with alpha-Ly-6.1 and complement had no effect on the ability of these cells to generate in vitro either T helper cells (TH) or T suppressor cells (TS) to SRBC. However, addition of antibody in the absence of complement during the generation of TH or TS, or posttreatment of these T cell subsets with antibody and complement after in vitro education, completely removed the functional activity of these cell types. Addition of alpha-Ly-6.1 to MLC suppressed the MLR as well as the generation of cytotoxic lymphocytes (CTL), whereas the presence of the antibody during a cell-mediated lympholysis (CML) had no effect. Therefore, it appears that alpha-Ly-6.1 recognizes an antigen that is important for the generation of TH and TS cell subsets.
Animals↗