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Biomedical subjects

S Boyd

Publications and source records attributed to S Boyd.

At least 19 recordsLinked to original sources
PubMed1992

Relationship of response to transurethral hyperthermia and prostate volume in BPH patients.

A response to transurethral microwave hyperthermia (TUHT) at 915 MHz and its relationship to prostate volume was examined in 63 poor surgical risk benign prostatic hyperplasia (BPH) patients. All patients had moderate-to-severe obstructive signs and symptoms, and received > or = 5 TUHT one-hour sessions. Treatment temperature was controlled on the urethral surface at 45 degrees C +/- 1 degree C. Follow-up ranged from twelve to forty-four months (mean 18 months). The mean prostate volume was 57 cc (range 10-301 cc). There were 40 patients (63%) with prostate volume < or = 50 cc and 23 (37%) with a volume > 50 cc. Treatment failure was seen in 6 patients (10%). It was 10 percent in 40 patients with smaller glands and 9 percent for those 23 with larger prostates, N.S. at p = 0.49. Subjective treatment response was seen in 58 patients (92%). It was 90 percent for the 40 patients with < or = 50 cc prostates vs. 96 percent for the 23 with > 50 cc prostates, N.S. at p = 0.75. This study suggests that the initial prostate volume is not an important parameter predicting response to TUHT.

Aged↗
PubMed1992

Surgical management of urethral strictures based on etiology. Where do urethral stents fit in?

Recent studies in the urologic literature indicate a renewed interest in the management of urethral stricture disease. Specifically, urologists are now treating all types of urethral strictures regardless of location, etiology, or extent with methods other than primary urethroplasty or direct vision internal urethrotomy (DVIU), i.e., balloon dilation or urethral stenting. To see which patients might best be managed by these new modalities, we reviewed our experience with urethral strictures at LAC-USC Medical Center.

Humans↗
PubMed1992

Progressive bulbar paralysis of childhood. A reappraisal of Fazio-Londe disease.

Fazio-Londe disease is a label sometimes applied to a degenerative disease of the motor neurons characterized by progressive bulbar paralysis in children. It is very rare with only 22 case reports describing 24 children including four sibling pairs. In two reports mothers and sons were affected. The neuropathology is described in only four cases. Previous authors have recognized that the condition is very heterogeneous. The clinical features of five children with this type of progressive bulbar paralysis, diagnosed at this hospital between 1969 and 1989, are reviewed, and in two cases neuropathological findings are detailed. Based on this experience, suggested criteria for diagnosis include clinical features of a pure motor neuronopathy affecting the bulbar nuclei, exclusion of other causes of progressive bulbar paralysis and positive support for the diagnosis from electromyography and/or pathological examination. A review of the literature, combined with the present series, suggests that there are at least three distinct subtypes: a very rare autosomal dominant form (as described by Fazio) and two variants with probable autosomal recessive inheritance either with early onset of respiratory symptoms and rapid progression to death or later onset, less prominent respiratory symptoms and protracted clinical course. There is strong concordance for each clinical pattern within families.

Bulbar Palsy, Progressive↗
PubMed1992

Discovery of a well-absorbed, efficacious renin inhibitor, A-74273.

The development of orally active renin inhibitors has been plagued by limited bioavailability in animals and humans. A-74273 is a novel, potent nonpeptide inhibitor of human renin (IC50 = 3.1 nM). This compound was absorbed into the portal and systemic circulations of anesthetized rats, ferrets, monkeys, and dogs after intraduodenal dosing. This favorable pattern also was observed after oral dosing in conscious animals, except in monkeys. Hepatic extraction of A-74273 was more efficient in rats and monkeys than in dogs or ferrets. A-74273 modestly inhibits dog renin, and when given orally as the base (0, 0.3, 1, 3, 10, and 30 mg/kg; n = 8 per dose) to conscious, salt-depleted dogs it induced dose-related reductions in mean arterial pressure and plasma renin activity. Peak falls in mean arterial pressure from normotensive baselines were -14 +/- 1, -26 +/- 3, and -44 +/- 3 mm Hg for the 3, 10, and 30 mg/kg groups, respectively (p < 0.05). Baseline plasma renin activity values (10.9 +/- 1.1-12.7 +/- 1.1 ng angiotensin I/ml/hr) were maximally inhibited, ranging from 43 +/- 8% at 0.3 mg/kg to 98 +/- 1% at 30 mg/kg. Bioavailability in this model was estimated to be 54 +/- 13% when plasma drug levels were determined by a renin inhibitory activity assay, but bioavailability was lower when compared with high-performance liquid chromatographic analysis of A-74273. This discrepancy was accounted for by the identification of structurally similar metabolites that are as active as the parent drug against human renin but much less potent against dog renin.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1991

Urinary tract stones: a complication of the Kock pouch continent urinary diversion.

Urinary tract stone disease has been found to be a later complication associated with the construction of the Kock pouch continent urinary diversion. Of 383 patients who underwent Kock pouch diversion between August 1982 and December 1986 stones developed in the pouch in 64 (16.7%), usually on exposed staples or eroded Marlex used to construct the nipple valves. Stones have recurred in 13 of the 64 patients (22%). Most stones were removed endoscopically with techniques similar to those used for percutaneous stone removal. Risk factors for stone formation include Marlex collar erosion and acute pyelonephritis. Changes in surgical techniques with elimination of the Marlex collar and a reduction in the number of staples have reduced the incidence of this later complication to 10%.

Female↗
PubMed1990

Functional properties of rat brain sodium channels expressed in a somatic cell line.

Transfection of Chinese hamster ovary cells with complementary DNA encoding the RIIA sodium channel alpha subunit from rat brain led to expression of functional sodium channels with the rapid, voltage-dependent activation and inactivation characteristic of sodium channels in brain neurons. The sodium currents mediated by these transfected channels were inhibited by tetrodotoxin, persistently activated by veratridine, and prolonged by Leiurus alpha-scorpion toxin, indicating that neurotoxin receptor sites 1 through 3 were present in functional form. The RIIA sodium channel alpha subunit cDNA alone is sufficient for stable expression of functional sodium channels with the expected kinetic and pharmacological properties in mammalian somatic cells.

Animals↗
PubMed1990

Management of animal and human bites in the head and neck.

Management of bites requires both local wound and systemic considerations. The authors will highlight their experience in 32 cases. Interestingly in this series, human bites were more common than animal bites. The bacteriology, antimicrobial therapy, and surgical treatment of human and animal bites will be reviewed. A management protocol that we use is based on whether the bite was inflicted by a human, dog, or other animal. The discussion will include cases demonstrating immediate and delayed reconstruction. Long-term follow-up was possible for a number of these patients.

Adolescent↗
PubMed1990

The blood-testis barrier in experimental unilateral cryptorchidism.

Unilateral cryptorchidism was induced in Wistar rat pups within 48 h of birth. After a period of 150 days, the blood-testis barrier was evaluated in the cryptorchid and contralateral scrotal testis, using a lanthanum immersion technique. The barrier was demonstrated to be competent, with tracer confined to the basal and intermediate compartments.

Animals↗
PubMed1990

Ataxia, developmental delay and an extensive neuronal migration abnormality in 2 siblings.

Two siblings with developmental delay and a non-progressive cerebellar ataxia are described. The electroencephalograms in both children showed a rather unusual pattern of high amplitude 10-12/s rhythms maximal anteriorly, while extensive neuronal migration abnormalities were apparent on Magnetic Resonance scans. There were no dysmorphic features, metabolic abnormalities, chromosomal defects or evidence of prenatal environmental toxins. It is considered that these siblings have an autosomal recessive neuronal migration defect which has not previously been reported.

Brain↗
PubMed1989

Continent urinary diversion.

From August 1982 through March 1988, 531 patients have undergone continent urinary diversion using an ileal reservoir constructed according to the method of Kock. For the last 18 months we have used the principle of Kock reservoir construction for primary lower urinary tract reconstruction after cystectomy in 39 highly selected male patients by means of a ureteroileal urethrostomy. Early complications occurred in 86 of 531 patients (16.2 per cent), resulting in an operative mortality rate of 1.9 per cent (10 of 531). The early complication rate was 16.5 per cent among patients undergoing 1-stage cystectomy and Kock pouch construction, and 15.2 per cent among patients undergoing Kock pouch conversion. Late complications have been analyzed in 489 patients who have undergone Kock cutaneous diversion. The complications unique to continent urinary diversion, their incidence and the effect of technical modifications in reducing the number of late complications are shown. Note that since the last modification in July 1985 the over-all incidence of late complication has decreased to 22 per cent. Based on this ongoing experience we conclude that the continent ileal reservoir, as conceived by Kock, remains the ideal internal reservoir for bladder replacement in terms of volume accommodation with the lowest internal pressures, and the intussuscepted ileal nipple valve mechanism is a reproducible, highly effective mechanism that prevents reflux and pyelonephritis in greater than 95 per cent of the patients and produces excellent continence. Our enthusiasm remains tempered by the need for reoperation in approximately 10 to 15 per cent of the patients, usually due to a pinhole fistula or false passage at the base of the efferent nipple valve mechanism. Electrolyte abnormalities rarely occur and in the absence of radiation gastrointestinal dysfunction is unusual. Continent urinary diversion is a viable concept that provides a real alternative in terms of quality of life and self-image for the patient who requires urinary diversion for any reason.

Adolescent↗
PubMed1988

Parametric studies on phencyclidine enhancement of 3H quinuclidinyl benzilate accumulation in vivo.

The purpose of these experiments was to define the temporal parameters involved in the phencyclidine (PCP) enhancement of 3H quinuclidinyl benzilate (QNB) accumulation in mouse brain. PCP enhanced QNB accumulation in brain if given intraperitoneally (IP) 1 and 4, but not 16 hours before intravenous (IV) administration of QNB. This effect was found in hypothalamus, striatum, cortex and hippocampus, but not cerebellum. PCP given after QNB did not alter QNB accumulation. The PCP enhancement persisted for at least 72 hours after QNB administration. These results confirm previous studies demonstrating that PCP must be present prior to QNB administration to enhance the accumulation and show that the effect persists for an extended period of time.

Animals↗
PubMed1988

Monitoring in non-traumatic coma. Part I: Invasive intracranial measurements.

The arterial blood pressure, intracranial pressure, and organ system failure scores were reviewed for 49 infants and children with non-traumatic coma from various causes. The neurological outcome was good in 21 patients, moderate in five, and poor in 23. There was no significant difference in maximum intracranial pressures between patients with a good outcome and those with a poor one, but patients with a poor outcome had significantly lower minimum cerebral perfusion pressures. During the period of admission 18 patients had cardiovascular failure, none had renal failure, and two developed severe coagulopathy. Seventeen of the 19 patients in whom at least one of these systems failed died. Our findings emphasise the diversity of illnesses associated with raised intracranial pressure in children and the number who develop multiple organ failure, and the values and limitations of using minimum cerebral perfusion pressure and the organ system failure scores as guides to severity of illness and prognosis.

Acute Disease↗
PubMed1988

Monitoring in non-traumatic coma. Part II: Electroencephalography.

Forty eight comatose children had electroencephalograms (EEG) recorded during the acute phase of their illnesses. These were classified according to a simple grading system and the findings correlated with the presence of seizures, deep coma, minimum cerebral perfusion pressure, and eventual neurological outcome. Serial EEGs proved important, particularly when slow activity was seen initially. None of the 20 patients who showed low amplitude EEG activity or electrocerebral silence at any stage of the acute illness did well. Discharges were seen in only 13 of the 29 patients with seizures and their presence did not correlate with outcome except in five patients with a distinctive pattern of discharges, none of whom had a good outcome. EEG findings associated with poor outcome did not always correlate with the clinical assessment of deep coma, emphasising the difficulties of neurological evaluation in these patients. Five of the patients with cerebral perfusion pressures greater than 42 mm Hg had a poor outcome that was predicted by serial EEGs. In nine patients with a minimum cerebral perfusion pressure in the borderline range 38-42 mm Hg the EEG was useful as an indication of the outcome. The EEG reflects changes in cerebral function which may be due to multifactorial or repeated insults. An EEG is therefore important in both the initial assessment and as an indicator of the neurological outcome, particularly in those patients in whom the cerebral perfusion pressure has apparently been adequate or within the borderline range.

Acute Disease↗
PubMed1987

Diagnostic difficulties in infantile neuroaxonal dystrophy. A clinicopathological study of eight cases.

The clinical features of eight children with infantile neuroaxonal dystrophy are presented. Diagnosis was established by brain biopsy (4 cases), conjunctival biopsy (1 case), and the family history (2 cases), while in one case a presumptive diagnosis was made on the combination of clinical and neurophysiological findings without histopathological confirmation. The pleomorphic clinical picture and variable neurophysiological findings make a firm diagnosis difficult without histopathological confirmation. However, in the appropriate clinical context, serial neurophysiological investigations (ERG, VEP, EEG, ENMG) may suggest the diagnosis after the age of 2 years. Conjunctival biopsy is not invariably helpful, and neuroaxonal spheroïds are not always demonstrated in brain biopsies by conventional techniques. However, they were consistently identified using a non-specific esterase stain and by electron microscopy. This technique is described, and the significance of ultrastructural and neuropathological findings in infantile neuroaxonal dystrophy is discussed.

Axons↗
PubMed1986

The development of a patchy organization of the rat striatum.

The rat striatum can be divided into patch and matrix compartments. Patches, as marked by high opiate receptor binding, first emerge perinatally from a dense, diffuse field of striatal opiate binding. Our quantitative analysis revealed that the patch compartment formed its peak proportion of the total striatal area at postnatal day 7. After this time, patches occupied a smaller proportion of the striatum, reflecting the fact that the number of patches and mean area per patch reached near adult levels during the first postnatal week, yet the volume of the striatum as a whole continued to increase for several weeks postnatally. Results from transplant and early postnatal lesion experiments suggested that connections between the striatum and other brain areas are important for the formation and/or maintenance of the patch and matrix compartments. Transplants of embryonic striatum to cavities in the cortex of young adult hosts developed diffuse opiate receptor binding but not dopamine receptor binding. Significantly, the opiate receptor binding seen in the transplants was never organized into the dense patches normally seen in the adult striatum. In a few transplants areas of relatively higher opiate receptor binding occurred in areas of relatively low neuronal cell density, as is seen in early normal development, but the dense adult patches never developed. Coronal diencephalic hemisections, but not decortications, in the early postnatal period produced drastic shrinkage of the striatum and, more importantly, a large decrease in opiate receptor patches when expressed as a proportion of total striatal area. Neuronal connections with more caudal brain structures may play a role in the final differentiation and maintenance of the striatal compartments.

Animals↗
PubMed1986

Endocrine and exocrine pancreatic function in treated coeliac disease.

Pancreatic function was assessed prospectively in a group of 18 treated adult coeliac patients, most of whom were asymptomatic. The para-aminobenzoic acid (PABA) test indicated exocrine pancreatic insufficiency in three patients, all of whom had persisting gastrointestinal symptoms. Arginine, 5 g intravenously, was used to stimulate pancreatic islet cells; basal and stimulated concentrations of plasma insulin, C-terminal glucagon, N-terminal glucagon, and blood glucose did not differ from asymptomatic nondiabetic control subjects. After gluten withdrawal, coeliac patients who responded clinically had no evidence of significant pancreatic impairment, but consideration of exocrine pancreatic insufficiency is worthwhile in those patients with persisting symptoms.

4-Aminobenzoic Acid↗