Acidosis stimulates beta-endorphin release during exercise

Elevated blood levels of beta-endorphin have been associated with high-intensity exertion, but the stimulus for beta-endorphin release is unknown. Some studies of exercise have associated beta-endorphin release with increased exertion levels, but other evidence suggests that acidosis may stimulate the release of beta-endorphin. This study examines acidosis as a possible stimulus for beta-endorphin release by examining the effects of arterial blood gases, whole blood lactate, and respiratory changes on beta-endorphin levels and by examining the effects of buffering during exercise on these levels. Initially, seven healthy adult males were evaluated during incremental exercise. During incremental exertion, indicators of acidosis correlated with endorphin levels: pH (r = -0.94), PCO2 (r = -0.85), HCO3- (r = -0.88), base excess (r = -0.94), and lactate (r = 0.89). A multivariate model showed that beta-endorphin levels were predicted best by the change in base excess. A time course analysis showed that beta-endorphin responses peaked postexercise and paralleled blood acid levels. Subsequently, subjects were compared after alkali loading and placebo during constant-intensity exercise at 85% of maximal exertion to determine whether acidosis is necessary for endorphin release. Treatment with a buffer, which effectively maintained pH above 7.40, significantly suppressed endorphin release (F = 3.07; P < 0.0001). The results of this study indicate that acidosis rather than any other physiological change associated with high-intensity exertion is the primary stimulus for beta-endorphin release.

Cystic fibrosis mutations in white and black Americans: an approach to identification of unknown mutations with implications for cystic fibrosis screening

OBJECTIVE

We sought to define the frequency of common cystic fibrosis mutations in white and black American probands from our geographic region.

STUDY DESIGN

Mutation analysis was performed for delta F508, G551D, G542X, R553X, S549N, an d N1303K. For probands with undetermined mutations single-stranded conformational polymorphism analysis was performed.

RESULTS

Among 40 white subjects with cystic fibrosis 26 (65%) were homozygous for delta F508, 10 (25%) were heterozygous for delta F508 and another unknown mutation, and two were homozygous for unknown mutations. Among 10 black probands one was homozygous for delta F508, seven (70%) were heterozygous for delta F508 and another unknown mutation, and one was homozygous for unknown mutations. Single-stranded conformational polymorphism analysis for selected exons was performed for 11 probands with unknown mutations. One mutation was detected in a white proband. Sequencing of this exon showed the mutation to be Q493X.

CONCLUSIONS

Thirty percent of white subjects and 80% of black subjects carried unknown mutations. In one family single-stranded conformational polymorphism was informative in identifying an undetermined cystic fibrosis mutation.

Mutations in the conserved domain of SRY are uncommon in XY gonadal dysgenesis

In order to evaluate the role of SRY in the determination of the testis, we sequenced the conserved domain of the SRY gene in 8 patients with 46,XY gonadal dysgenesis and 3 patients with related disorders, and compared our data with those obtained in 6 other similar studies. In our study, a 609-bp fragment of SRY was amplified by the polymerase chain reaction and the internal conserved motif was sequenced. SRY sequences did not differ from those in normal males in any of our patients. Overall, 5 de novo mutations have been identified among 56 patients with sporadic XY gonadal dysgenesis (8.9%), and 2 de novo mutations have been identified among 18 patients with related conditions (11%). The unexpectedly low frequency of mutations within the SRY conserved domain in these patients could be caused by undetected Y-linked mutations outside the conserved domain in regions that control transcription during development (e.g., promoter/enhancer regions) or to downstream mutations in other sex-determining genes that need not map to the Y.

Incorrect positioning of nasogastric feeding tubes and the development of pneumothorax

The authors describe 12 patients in whom feeding tubes were inadvertently placed in the bronchial tree a total of 14 times. All but four of the misplacements were complicated by pneumothorax. No deaths were directly attributable to the misplacements, although one cardiac arrest occurred as a late complication of intrapleural feeding. Careful, controlled insertion of feeding tubes and radiographic confirmation of their placement are essential to reduce morbidity and mortality.

Isolated colonic hemangioma in a child

Hemangiomas of the large bowel are very rare and usually occur in the rectosigmoid. A large cavernous hemangioma of the colon was demonstrated in a 9-month-old child who presented with recurrent lower gastrointestinal tract bleeding. Barium examination demonstrated an annular lesion of the hepatic flexure. Computed tomography demonstrated the extent of the lesion, and contrast enhancement suggested the vascular nature of the tumour before a laparotomy was performed to remove the tumour.

Presacral extramedullary hematopoiesis in thalassemia intermedia

Extramedullary hematopoiesis is manifested by several clinical hematologic disorders including beta-thalassemia major and thalassemia intermedia. We report an unusual case of extramedullary hematopoiesis, which presented as a painful presacral mass in a patient with beta-thalassemia intermedia. The diagnosis was confirmed by a needle biopsy guided by computed tomography. The patient responded well to radiation therapy to the sacral region.

Halogenated inhalation anesthetic agents decrease transepithelial electrical measurements across the isolated iris-ciliary body

Transmembrane electrical measurements were performed on the isolated rabbit iris-ciliary body (I-CB) to study the direct effects of halogenated inhalation anesthetic agents on the ciliary epithelium. Addition of either halothane, enflurane, or isoflurane to the control 95% O2:5% CO2 gas mixture resulted in a dose-dependent decrease in the short-circuit current (SCC) and potential difference (PD). This response was reversible after the anesthetic gas was discontinued. Pretreatment with either alpha-adrenergic or beta-adrenergic antagonists (phentolamine or timolol) had no effect on the halothane-induced decrease in SCC. Delivery of the analgestic gas N2O did not alter baseline electrical measurements across the isolated I-CB.

The Koch pouch: radiographic evaluation of the orthotopic and cutaneous forms

The Koch pouch is a continent ileal reservoir. It has several advantages over the standard ileal conduit. The pouch can be attached to the skin (cutaneous type) or the male urethra (orthotopic type). Both variations have special imaging considerations. The suggested imaging protocol is based upon experience with 47 patients (22 with orthotopic and 25 with cutaneous pouches). The normal appearance of the new and mature pouch and its complications and their management are presented.

Glycolipid receptor binding specificity of exoenzyme S from Pseudomonas aeruginosa

By use of the tlc overlay procedure we have shown that exoenzyme S extracted from cultures of Pseudomonas aeruginosa specifically binds to the glycolipids asialoGM1, asialoGM2 and to a lesser extent lactosyl ceramide. More significantly, strong binding was also observed to the glycerolipid receptor we have detected for Helicobacter pylori (Lancet ii, 238-241.1989). Exoenzyme S can be extracted in a toxic and nontoxic form. Toxicity correlated with ability to bind the H. pylori receptor. This species was the only receptor detected in the most sensitive cell lines. The relative binding of exoenzyme S to the ganglio series glycolipids and the glycerolipid receptor was modified in a reciprocal manner in the presence of metal ions, suggesting that exoenzyme S has two interrelated receptor binding sites.

Late-onset cystic hygromas: the role of CT

Cystic hygromas usually present in the first two years of life. We report a retrospective study of nine patients who first presented with neck and mediastinal masses after two years of age. The clinical evaluation of size, margins, and presence of respiratory symptoms can be used to select those requiring preoperative computed tomography. The five patients who had this examination all demonstrated mediastinal or axillary involvement. Patients in this older subset appear to be different from those presenting as infants because of the incidence of extension and the frequency with which disease is found outside of the posterior triangle.

Inflammatory abdominal aortic aneurysm: a cause of urinary obstruction and acute renal failure

Abdominal aortic aneurysms are rare causes of ureteric obstruction. We report three cases of inflammatory abdominal aortic aneurysm producing hydronephrosis. In two patients acute renal failure preceded this presentation. The diagnosis can be established by computed tomography when mural thrombus, wall calcification, and an enhancing periaortic soft-tissue mantle are present. It is important to recognize this disease preoperatively.

Computers in hospital management and improvements in patients care--new trends in the United States

This article discusses the current state of informations systems in hospital management. Decision Support Systems (DSS) for the management, administrative and patient care units of the hospital are described. These DSS's include market planning, nurse scheduling and blood screening systems. Trends for future uses of information systems in the hospital environment are addressed.