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Biomedical subjects

B White

Publications and source records attributed to B White.

At least 19 recordsLinked to original sources
PubMed1991

Abdominal cerebrospinal fluid pseudocyst: occurrence after intraperitoneal urological surgery in children with ventriculoperitoneal shunts.

Increasingly, children with ventriculoperitoneal shunts are undergoing urinary tract reconstructive surgery with bowel. The peritoneal end of the ventriculoperitoneal shunt tubing usually is exposed during the procedure, making the system vulnerable to infections and malfunction. The records of 103 myelomeningocele children with ventriculoperitoneal shunts and bowel-bladder reconstructive surgical procedures (27) were reviewed for evidence of an abdominal cerebrospinal fluid pseudocyst (6). Pseudocyst formation occurred in only 1 of 76 ventriculoperitoneal shunt patients (1.3%) who had not undergone versus 6 of 27 (22%) who had undergone an intra-abdominal procedure. The 6 children had a total of 8 pseudocysts, including 7 pseudocysts that developed 8 days to 47 months (average 15.1 months) after the reconstructive surgery and 1 that developed before reconstructive surgery. All patients had abdominal symptoms (pain or mass) or symptoms of increased intracranial pressure. Treatment included computerized tomography-guided needle aspiration or abdominal exploration with cyst evacuation and shunt repositioning or replacement. The walls of the pseudocyst were formed by matted loops of bowel. Additional shunt surgery was required in 5 patients with conversion to ventriculoatrial shunts. We conclude that the development of an abdominal cerebrospinal fluid pseudocyst is at least in part related to the prior abdominal surgery. Thus, pediatric urological and general surgeons caring for children with ventriculoperitoneal shunts should be aware of this complication.

Abdomen↗
PubMed1991

A report of familial carotid body tumors and multiple extra-adrenal pheochromocytomas.

A case of familial carotid body tumors and multiple extra-adrenal pheochromocytomas is reported. The carotid body tumors, resected previously, were bilateral and associated with 4 intra-abdominal extra-adrenal pheochromocytomas. Magnetic resonance imaging was far superior to computerized tomography and 131iodine-metaiodobenzylguanidine in visualizing the intra-abdominal lesions, and may soon become the imaging technique of choice in the evaluation of patients with suspected pheochromocytoma.

3-Iodobenzylguanidine↗
PubMed1991

Use of the BD-100R as a neutron spectrometer through applied pressure variation.

A study was undertaken to demonstrate the feasibility of using the well-characterized BD-100R neutron bubble dosimeter as a neutron spectrometer in low-level radiation fields. The BD-100R dosimeters used in this work consisted of a test tube containing an elastic polymer with interspersed droplets of two types of Freon: Freon-12 and Freon-114. Each superheated liquid droplet is a potential nucleation site, with the minimum energy needed to form a bubble at the nucleation site being inversely proportional to the square of the difference between the applied and the vapor pressure (i.e., Emin alpha(delta P)-2. For a given dose, the number of bubbles formed continually decreases with increasing applied pressure, until a pressure is reached where no bubbles are formed, since the energy transferred can no longer vaporize the Freon. This investigation is intended to demonstrate the feasibility of measuring an unknown spectrum utilizing the dosimeter response (number of bubbles formed) as a function of the neutron energy (applied pressure). A set of 12 dosimeters was exposed under various applied pressures in a well-characterized neutron energy spectrum at the East Beam Port (EBP) of the Maryland University Training Reactor (MUTR). The dosimeters were placed inside a pressure chamber that could accommodate up to 18 dosimeters. Energy response coefficients (cross-sections) were obtained by spectral unfolding techniques on the known spectrum. The same set of dosimeters were then irradiated using a paraffin-moderated Pu/Be source. Measured spectral estimates obtained using the response coefficients were compared with numerical computations generated using the ANISN computer code. The results indicate that further research using the BD-100R as a neutron spectrometer in low radiation fields is warranted.

Neutrons↗
PubMed1990

The effects of talc pleurodesis on growing swine.

Talc pleurodesis is an effective means of preventing recurrent pneumothorax. We have successfully applied talc pleurodesis with thoracoscopy in children with cystic fibrosis presenting with pneumothorax. However, little is known about the effects of talc pleurodesis on lung compliance in growing children. Therefore, six young pigs (10 weeks old, weighing 15 +/- 1 kg) were prepared for study. In each pig, one hemithorax underwent thoracoscopy and talc pleurodesis (TALC). The other hemithorax underwent either thoracoscopy alone or no procedure (CONTROL). Dynamic and static respiratory mechanics were studied 5 and 10 weeks later. Air flow and airway pressure were measured to calculate dynamic transpulmonary and transrespiratory compliance, and static transpulmonary compliance. At 5 weeks, dynamic transpulmonary and transrespiratory compliance were less in the TALC lungs when compared with CONTROL lungs. At 10 weeks, the differences in dynamic transpulmonary and transrespiratory compliance between the TALC and CONTROL lungs had resolved. Static compliance was lower in the TALC lungs than in the CONTROL lungs at both 5 and 10 weeks, but this was significant only at 10 weeks. There was an improvement in static compliance in the TALC lungs between 5 and 10 weeks, but this only approached significance. At autopsy, there were marked adhesions and pleural thickening in the talc lungs. Histological examination demonstrated no differences in lung parenchyma between the TALC lungs and the CONTROL lungs. Talc pleurodesis causes a temporary impairment in dynamic transpulmonary and transrespiratory compliance that resolves with time and growth. Static compliance is more persistently compromised, but a trend toward improvement with time and growth exists.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Regional cerebral glucose metabolism is normal in young adults with Down syndrome.

Regional CMRglc (rCMRglc) values were measured with [18F]2-fluoro-2-deoxy-D-glucose (18FDG) and positron emission tomography (PET), using a Scanditronix PC-1024-7B scanner, in 14 healthy, noninstitutionalized subjects with trisomy 21 (Down syndrome; DS) (mean age 30.0 years, range 25-38 years) and in 13 sex-matched, healthy volunteers (mean age 29.5 years, range 22-38 years). In the DS group, mean mental age on the Peabody Picture Vocabulary Test was 7.8 years and dementia was not present. Resting rCMRglc was determined with eyes covered and ears occluded in a quiet, darkened room. Global gray CMRglc equaled 8.76 +/- 0.76 mg/100 g/min (mean +/- SD) in the DS group as compared with 8.74 +/- 1.19 mg/100 g/min in the control group (p greater than 0.05). Gray matter regional measurements also did not differ between groups. The ratio of rCMRglc to global CMRglc, calculated to reduce the variance associated with absolute rCMRglc, and right/left ratios did not show any consistent differences. These results show that healthy young DS adults do not have alterations in regional or global brain glucose metabolism, as measured with 18FDG and PET, prior to an age at which the neuropathological changes in Alzheimer disease are reported to occur.

Adult↗
PubMed1990

Expectancy effects in caffeine research.

The impact of expectancy on the experience of caffeine-related symptoms was investigated by randomly assigning subjects to an expectancy or nonexpectancy instructional condition. Subjects were administered the State-Trait Anxiety Inventory and a Symptom Questionnaire prior to and 45 minutes after receiving their designated instructional set and ingesting a cellulose-filled gelatin capsule which ostensibly was filled with caffeine. Results revealed that a significant expectancy effect existed on five Symptom Questionnaire items.

Adult↗
PubMed1989

Heterotopic lingual brain in the newborn.

Heterotopic brain is a rare entity. Histologically, this lesion resembles mature brain and often contains specialized tissues similar to choroid plexus or glia. Specialized neural stains are necessary to differentiate this rare anomaly from other tumors or conditions found in the head and neck. The differential diagnosis includes squamous cell carcinoma, granular cell tumor, hemangioma, lymphangioma, thyroglossal duct cyst, dermoid cyst, hamartoma, rhabdomyosarcoma, and teratoma. We describe a newborn with heterotopic brain tissue occurring on the dorsum of the tongue. We found only one other description of this developmental aberration in the English literature. Our patient was successfully treated with carbon dioxide laser excision of the mass. There has been no evidence of complication or recurrence after one year of follow-up.

Brain↗
PubMed1989

Absorption of a first trimester fetus.

A case of an 8-week fetus with ultrasound demonstrated heart beat, which was absorbed completely prior to abortion at 11 weeks' gestation, is reported.

Adult↗
PubMed1988

Chemo/radiation with and without surgery in the thoracic esophagus: the Wayne State experience.

Wayne State University was the site of one of the initial experiences with combination chemotherapy, radiation, and surgery for carcinoma of the thoracic esophagus. This review analyzes all the patients seen with thoracic esophageal carcinoma from 1980 to 1984 inclusive, plus an additional 22 patient pilot study. The great majority of patients seen were treated with combination radiation and chemotherapy, which may have a greater applicability than dose esophagectomy. Eighty-nine patients completed planned preoperative treatment consisting of (5-FU cisplatin and radiation therapy). Of these patients, 39 patients refused or were not offered surgery, and 4 patients are still alive and well several years from treatment initiation. Fifty patients underwent esophagectomy. Twelve of this patients were free of tumor at esophagectomy, and 4 of these are still alive and well several years from treatment. One patient with residual tumor in the esophagectomy specimen alone is still alive. Because of disappointing results and surgical mortality risk, 22 patients were entered on the pilot study, increasing the tumor dose of 5,000 cGy, and increasing chemotherapy to 4 courses. Six patients are still alive in this small series. Since the results of radiation and chemotherapy combination approximates that of best prior trials of radiation therapy alone, a randomized study has been initiated comparing these treatment plans to determine if the combination of radiation and chemotherapy is superior to radiation alone.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Xenopus tadpole melanophores are controlled by dark and light and melatonin without influence of time of day.

Melanophores were studied in tadpoles of the South African clawed toad, Xenopus laevis, during the first week after hatching (stages 46-49) at 25 degrees C. The tadpoles had melanophores with dispersed melanosomes in the light and punctate melanophores in the dark in LD 12:12. The melanophores remained punctate in constant dark and the melanosomes remained dispersed in constant light. Lights-out (in the light-time of LD 12:12) caused the melanophores to become punctate, which occurred more quickly than the dispersion of melanosomes, which commenced when the lights were turned on (in the dark-time of LD 12:12). Melanophores with dispersed melanosomes in tadpoles (in constant light) became punctate in response to a series of melatonin concentrations (0.2-5 ng/ml) in their bathing water irrespective of the time of day melatonin was administered. An image-analysis technique for assessing melanophore responses was tested.

Animals↗
PubMed1987

Cerebral endothelial microvilli following global brain ischemia in dogs.

Cerebral blood vessels (BVs) of dogs subjected to global brain ischemia by complete cardiac arrest of 15 min followed by 8 h of reperfusion, were studied in neocortex and hippocampus by means of transmission electron microscopy. Widespread endothelial microvilli were present in the postischemic animals. The number of endothelial microvilli in the postischemic animals (mean/BV in the neocortex = 3.26 and in the hippocampus = 2.54) was significantly larger than that in the non-ischemic controls (mean/BV in the neocortex = 1.39 and in the hippocampus = 0.84), P for both regions being less than 0.05. Arterioles, venules and capillaries, all were equally affected. Endothelial pinocytotic vesicles were also observed frequently in the postischemic dogs. Marked pericapillary swelling of astrocytic foot processes was present in the surrounding neuropil. It is concluded that the prominent cerebral endothelial microvilli recognized after 8 h of reperfusion following cardiac arrest in this experimental model of global brain ischemia, may play a significant role in the development of delayed postischemic hypoperfusion.

Animals↗
PubMed1987

Effect of flunarizine on global brain ischemia in the dog: a quantitative morphologic assessment.

The effects of flunarizine, a calcium antagonist, were evaluated in an experimental model of global brain ischemia produced by 15 min of cardiac arrest followed by resuscitation and reperfusion. One group of dogs received flunarizine (0.1 mg/kg intravenously during a 10-min period) at the onset of resuscitation. Another group of dogs underwent cardiac arrest, resuscitation, and reperfusion but did not receive flunarizine. A third group served as nonischemic control. In situ-fixed brains of all animals (nonischemic controls and the postischemic dogs after 8 h of reperfusion) were examined for anoxic ischemic injury. Quantitation of the ischemic neurons was carried out in parietal cortex, hippocampus, and cerebellum by using an image analysis system. Significant difference in the number of necrotic neurons between the flunarizine-treated group and the ischemic controls was noted in the hippocampus only; the mean percentage of necrotic neurons in the two groups being 14.8 +/- 9.6 and 29.3 +/- 12.1, respectively (P less than 0.05). These results indicate that flunarizine has an ameliorating effect on neuronal injury in the hippocampus that follows cardiac arrest in this experimental model of global brain ischemia. However, flunarizine was not found to be effective in reducing the ischemic neuronal damage in the cortex or the cerebellum.

Animals↗
PubMed1987

Decline in cerebral glucose utilisation and cognitive function with aging in Down's syndrome.

The cerebral metabolic rate for glucose (CMRglc) was measured with positron emission tomography and [18F]2-fluoro-2-deoxy-D-glucose in 14 healthy subjects with Down's syndrome, 19 to 33 years old, and in six healthy Down's syndrome subjects over 35 years, two of whom were demented. Dementia was diagnosed from a history of mental deterioration, disorientation and hallucinations. All Down's syndrome subjects were trisomy 21 karyotype. CMRglc also was examined in 15 healthy men aged 20-35 years and in 20 healthy men aged 45-64 years. All subjects were at rest with eyes covered and ears plugged. Mean hemispheric CMRglc in the older Down's syndrome subjects was significantly less, by 23%, than in the young Down's syndrome group; statistically significant decreases in regional metabolism (rCMRglc) also were present in all lobar regions. Comparison of the younger control group with the older control group showed no difference in CMRglc or any rCMRglc (p greater than 0.05). Assessment of language, visuospatial ability, attention and memory showed significant reductions in test scores of the old as compared with the young Down's syndrome subjects. These results show that significant age differences in CMRglc and rCMRglc occur in Down's syndrome but not in healthy controls, and that, although only some older Down's syndrome subjects are demented, significant age reductions in neuropsychologic variables occur in all of them.

Adolescent↗
PubMed1987

Membrane biochemistry of the ouabain-resistant potassium transport system.

A 6.5-kilobase fragment of genomic DNA from mutant mouse cells under ouabain selection pressure conferred ouabain resistance when transfected into ouabain-sensitive CV1 green monkey fibroblasts. Ouabain resistance was induced in the presence of 10 microM ouabain. Amiloride (500 microM) completely blocked ouabain-insensitive 86Rb+ uptake into these cells. Plasma membranes from these cells demonstrated little sodium-dependent adenosine triphosphatase (ATPase) activity but had potassium-dependent and ouabain-resistant p-nitrophenylphosphatase activity. Like Na+,K+-ATPase this activity was vanadate- and sodium-inhibitable. Also, like the Na+,K+-ATPase, sodium inhibition of the p-nitrophenylphosphatase was reversed by 10 microM adenosine 5'-triphosphate.

4-Nitrophenylphosphatase↗
PubMed1987

Quantitative CT analysis of brain morphometry in adult Down's syndrome at different ages.

Quantitative CT demonstrated that healthy adults with Down's syndrome (DS) have smaller brains and smaller intracranial volumes than controls. Normalized volumes of CSF, ventricles, and brain parenchyma did not differ in patients and controls. Both DS subjects and controls showed similar significant age-related increments in volumes of CSF and ventricles. Of seven older DS subjects, one was demented, whereas the group as a whole showed reductions in cognitive test scores as compared with younger DS subjects. The results demonstrate cognitive decline in older DS subjects, but no brain atrophy other than that expected with aging.

Adult↗
PubMed1986

The use of the carbon dioxide laser in head and neck lymphangioma.

The carbon dioxide laser has been used to treat various lesions of the head and neck, ranging from carcinomas to hemangiomas, and even including tatoos. A search of the literature does not reveal any reports of the carbon dioxide laser being used to treat lymphangioma. This report discusses the efficacy of treating lymphangioma of the air and food passages with the carbon dioxide laser, and presents three patients who have been treated in this fashion-two for palliation and one for cure.

Carbon Dioxide↗