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Biomedical subjects

A Wald

Publications and source records attributed to A Wald.

At least 181 records · Page 10Linked to original sources
PubMed1975

Effects of changes in serum osmolarity on bulk flow of fluid into cerebral ventricles and on brain water content.

The effects of changes in serum osmolarity on the rate and osmolarity of bulk flow of fluid into the cerebral ventricles and on cortical white and grey matter water content were studied in cats. Bulk flow rates and osmolarities were measured during ventriculocisternal perfusion both before and after intravenous infusion of glucose solutions. Infusions of glucose in concentrations greater than 6% decreased fluid bulk flow rate and its osmolarity. Glucose in concentrations less than 6 percent increased fluid bulk flow rate and decreased its osmolarity. Bulk flow rate and serum osmolarity were found to be linearly related with a coefficient of osmotic flow of minus 0.835 mul/min per mOsm/l. At the extremes of induced serum osmolarities, (290 and 360 mOsm/l) bulk flow rate was either increased by 120 percent or completely inhibited. Effluent osmolarity also increased proportionately to serum osmolarity (0.338 mOsm/l per mOsm/l). When compared to controls, cortical grey and white matter water content increased by 1.9 percent and 2.9 percent, respectively, when the infused glucose concentration was 2.5 percent or less, and decreased by 1.8 percent and 2.9 percent when the concentration was 10 percent or more. The results of these experiments suggest that the increased bulk flow comes from the brain, rather then directly from the blood.

Animals↗
PubMed1975

The role of fiberoptic endoscopy in the diagnosis and management of duodenal neoplasms.

This is a study of 11 cases of duodenal tumors encountered in 1200 consecutive duodenoscopic examinations over a 34-month period at The Johns Hopkins Hospital. Of these tumors, 4 were benign and 7 malignant. Endoscopic removal of 2 benign tumors was accomplished without morbidity and obviated the necessity for transabdominal surgery. The 2 other benign tumors were a probable lipoma and a benign polyp, and did not require surgical intervention. In 6 of the 7 patients with malignant lesions, the indication for performing duodenoscopy was an abnormal roentgenographic study. In each case, direct visualization of the abnormal area, together with biopsy and cytologic brushing, provided a definitive diagnosis of malignant disease and helped plan the therapeutic course. In the seventh patient, a primary adenocarcinoma at the duodenojejunal junction was found on endoscopic examination, after all other available diagnostic studies to find the cause of persistent gastrointestinal bleeding had been exhausted. Although duodenal tumors are not common, they were encountered in 1 of every 100 duodenoscopies at a referral center. With increasing use of fiberoptic endoscopy, such tumors will undoubtedly be seen with increasing frequency. In our experience, endoscopy has proved to be a safe and reliable method of distinguishing between benign and malignant duodenal neoplasms and of assistance in planning subsequent management.

Adenocarcinoma↗
PubMed1975

Avoidance of shunt dependency in hydrocephalus.

An approach to the treatment of neonatal hydrocephalus is proposed which is intended to reduce or eliminate shunt dependency by increasing the effectiveness of remaining pathways of absorption of cerebrospinal fluid. In suitable cases, intermittent cranial compression by means of an elastic bandage or a helmet with an inflatable inner-lining may be effective. Hydrocephalus was arrested in nine of 14 children treated with this method, eight of whom have developed normally. When cranial compression is contra-indicated or not successful, the preferred method of treatment is an 'on-off' type of valve which is used intermittently to drain a fixed volume of cerebrospinal fluid. Of 18 children who had such shunts inserted, 10 have become totally independent of their shunts and their hydrocephalus has become compensated. All are of normal intelligence. Subtemporal craniectomy was performed on seven shunt-dependent children with recurrent catheter obstruction. Four have been followed for six months and three for two years and in no case has there been further malfunction of the proximal catheter.

Cerebrospinal Fluid Shunts↗