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Biomedical subjects

R D Bell

Publications and source records attributed to R D Bell.

At least 19 recordsLinked to original sources
PubMed1979

Effect of phenytoin on bone and vitamin D metabolism.

Calcium and vitamin D metabolism were evaluated in 5 adult epileptic patients before and during treatment with phenytoin. Significant decreases occurred in serum concentrations of calcium, albumin, and 25-hydroxy-cholecalciferol. The decreases in serum calcium paralleled those in serum albumin. Significant increases occurred in serum alkaline phosphatase and 1 alpha, 25-dihydroxycholecalciferol, in urinary hydroxyproline, and in the fractional gastrointestinal absorption of calcium. Urinary cyclic adenosine monophosphate and serum parathyroid hormone did not change. The results suggest that the bone disease resulting from phenytoin therapy may be associated with a deficiency of 25-hydroxycholecalciferol and not of 1 alpha, 25-dihydroxycholecalciferol, and that reduced gastrointestinal absorption of calcium or changes in parathyroid function may not be necessary for the development of bone disease.

Adult↗
PubMed1979

Lorazepam in status epilepticus.

Lorazepam, a dichloro-3-hydroxy-1,4-benzodiazepine, has been shown to be a potent anticonvulsant in animal models of epilsepsy and has minimal depressant effects on respiration and circulation in humans. The effects of this compound were studied in status epilepticus. Twenty-five patients were given intravenous lorazepam during status epilepticus of varying cause. Four or 8 mg of the drug controlled status in 22 of the 25 patients. Although single seizures recurred in 5 of the 22 patients, none experienced recurrence of status during a prolonged follow-up period. Transient respiratory arrest occurred in 1 patient, but no other significant complications were observed. Studies of plasma drug levels suggest that most patients attain good seizure control at concentrations between 30 and 100 ng per milliliter. Clinical observations indicate that repetitive injections are not required for continuing control of seizures in patients whose seizures are initially controlled. Lorazepam appears to be an effective and safe drug for treatment of status epilepticus, with a duration of control longer than that achieved with diazepam.

Adolescent↗
PubMed1979

Unusual parapharyngeal lesions.

Six cases of unusual parapharyngeal lesions are presented in detail along with discussions of the anatomy, pathology, clinical aspects, and treatment methods of lesions in the parapharyngeal space. Newer techniques of CT scanning and selective embolization are discussed as they apply to management of such lesions. A plasmalymphocytic tumor with amyloidosis is described. The authors believe that such a lesion has not been reported previously in the parapharyngeal space.

Adenoma, Pleomorphic↗
PubMed1978

Creatine kinase BB isoenzyme levels by radioimmunoassay in patients with neurological disease.

Creatine kinase BB (CK-BB) isoenzyme was measured by radioimmunoassay in serum and in cerebrospinal fluid from 61 patients with various neurological disorders. Statistically significant elevations of CK-BB isoenzyme in the serum were observed in patients with acute cerebrovascular accidents and in those with seizures and a prolonged alteration in level of consciousness. Statistically significant elevations of CK-BB isoenzyme in the cerebrospinal fluid were also found in patients who had suffered acute cerebrovascular accidents. Some patients with central nervous system infections, acute demyelinating disease, certain drug overdoses, head trauma, and complex migraine also had elevations of serum and CSF CK-BB isoenzyme. In 2 patients with elevations of CK-BB isoenzyme, the elevations in serum occurred later than those detected in the cerebrospinal fluid. If CK-BB elevations determined by radioimmunoassay can be demonstrated to be quantitatively related to the extent of brain damage, then these determinations in conjunction with experimental animal models and newer radiological techniques should allow evaluation, in an objective and precise manner, of measures designed to decrease that damage.

Brain Damage, Chronic↗
PubMed1978

Effect of dopamine agonist (Lergotrile mesylate) therapy on twenty-four hour secretion of prolactin in treated Parkinson's disease.

Plasma PRL was measured at 20-min intervals in six patients with Parkinson's disease under various treatment protocols. In addition, 24-h mean GH levels were measured. The results of these studies showed that two untreated patients with Parkinson's disease had normal 24-h mean PRL levels with the normal increase during sleep. During chronic treatment with L-dopa-carbidopa (Sinemet), the 24-h PRL level was 12.8 +/- 4.9 ng/ml (mean +/- SD) and there was persistence of augmented PRL secretion during sleep. The 24-h mean GH level ranged from 1.5-4.4 ng/ml, with a mean of 2.5 ng/ml. The addition of a dopamine agonist (Lergotrile mesylate) resulted in a significant (P less than 0.01) suppression of the 24-h mean PRL levels and abolition of the normal sleep augmentation after 2 weeks of therapy. This suppression was maintained in one patient who was restudied 4 months after the addition of dopamine agonist therapy to L-dopa-carbidopa. The 24-h mean GH levels did not change significantly after the addition of the dopamine agonist when compared to L-dopa-carbidopa alone. These results suggest a dichotomy between the PRL and GH responses to combined L-dopa-carbidopa and dopamine agonist therapy. In addition, the preservation of normal PRL regulation in the two untreated patients with Parkinson's disease suggests that dopaminergic neurons are not universally affected in this disorder.

Adult↗
PubMed1978

Oncocytic lesions of the larynx.

Eight cases of laryngeal oncocytic lesions treated at Toronto Western Hospital between 1957 and 1977 are reviewed. The typical clinical course was of a benign lesion with prolonged dysphonia. A smaller number with bulkier lesions developed symptoms of airway obstruction. The lesions were supraglottic and cystic. They were excised either endoscopically or via a laryngofissure. The pathologic features support the concept that the lesion represents a metaplasiahyperplasia, and therefore the term 'oncocytic cyst' is preferred to terms which imply a neoplastic process. Three patients with oncocytic cysts had associated squamous dysplasia of the vocal cord. Pathologically this supports the theory of tissue response to chronic irritation, since all three were heavy smokers. Clincially the finding necessitates longterm follow-up with a view to possible squamous cell carcinoma that may arise on the true cords. Follow-up in this series showed no recurrence of symptoms in six of eight cases, two being lost to follow-up.

Adult↗
PubMed1978

Effects of acute and chronic splenectomy on experimental acute renal tubular lesions.

The first half of this study describes the effects of acute splenectomy on epinephrine-induced ATL in the dog. Renal morphology and hematocrit were compared in 12 dogs without splenectomy (group I), six dogs with antecedent splenectomy (group II), and seven dogs with antecedent splenectomy after splenic contraction was induced by topical application of epinephrine (group III). Splenectomy was performed in groups II and III 20 to 30 min prior to epinephrine infusion; all three groups received equal infusions (4 microgram/kg/min) for 6 hr before the kidneys were harvested. ATL and renal congestion were consistently severe in group I but infrequent and less severe in groups II and III. The second half of this study describes the apparent protective effect of chronic (2-week) splenectomy on epinephrine-induced ATL. Renal morphology and hematocrits were compared in 13 intact dogs (group IV) and 10 dogs splenectomized 2 weeks before the epinephrine infusion (group V). The severity of the ATL and the degree of renal congestion were significantly less in the chronically splenectomized dogs. This chronic protection afforded by acute and chronic splenectomy observed after epinephrine infusion remains unclear.

Animals↗
PubMed1977

Narcotics and the hypothalamic-pituitary-gonadal axix: acute effects on luteinizing hormone, testosterone and androgen-dependent systems.

The effects of narcotics on several aspects of the hypothalamic-pituitary-gonadal axis were examined in the male rat. Our results indicate that a large number of narcotics acutely depress serum luteinizing hormone levels and that these reduced gonadotropin levels lead to a subsequent fall (1-2 hours later) in serum testosterone levels. The luteinizing hormone-depleting effect of the narcotics appears to represent a specific narcotic action since the (-)-isomers of the narcotics were much more effective than the ()-isomers, naloxone antagonized their effects and tolerance rapidly developed. Further, our studies indicate that the impairment of the functional and structural integrity of the secondary sex organs produced by chronic narcotic administration is not due to a direct effect of these drugs since they have no effect on the uptake of subcellular distribution of testosterone in the secondary sex organs or on the androgen-dependent accumulation of myo-inositol. Consequently, it appears that the testosterone depletion produced by the narcotics is solely responsible for their adverse effect on the secondary sex organs. The results of these studies suggest that the effects of the narcotics on the hypothalamic-pituitary-gonadal axis are confined to either the hypthalamus or the pituitary gland.

Androgens↗
PubMed1976

Effects of morphine and methadone on serum testosterone and luteinizing hormone levels and on the secondary sex organs of the male rat.

The effects of morphine and methadone on the endocrine control of the male rat's sexual function were examined. The results indicate that these narcotics markedly reduce the structural and functional integrity of the secondary sex organs by producing a pronounced reduction in serum testosterone levels. Serum levels of luteinizing hormone (LH) were not detectable in narcotic-treated animals, whereas serum levels of the follicle stimulating hormone (FSH) were unaltered. On the basis of these observations, it seems reasonable to conclude that the narcotics inhibit the secretion of LH, by an action either in the hypothalamus (e.g., suppression of LH-releasing hormone) or directly in the pituitary gland, which leads to a reduction in serum testosterone levels and a subsequent reduction in the wet-tissue weight and secretory activity of the secondary sex organs.

Age Factors↗
PubMed1976

Acute reductions in serum testosterone levels by narcotics in the male rat: stereospecificity, blockade by naloxone and tolerance.

The effects of a single injection of morphine (20 mg/kg) on serum testosterone levels were examined in the male rat. Within 2 hours after the morphine injection, testosterone levels were significantly lower than control levels. The decline in testosterone levels reached a maximum 4 hours after the administration of morphine, at which time testosterone levels were reduced by more than 85% with respect to controls. The ability of a large number of narcotics to depress serum testosterone levels, 4 hours after their administration, was also examined. All narcotics depressed testosterone levels significantly and their potency relative to morphine was comparable to that observed in several other preparations, such as the guinea-pig ileum and mouse vas deferens. The testosterone-depleting effects of the narcotics appear to represent specific narcotic effects since the (-)-isomers of the narcotics were considerably more potent than the (+)-isomers, naloxone competitively inhibited the effects of morphine on testosterone levels and tolerance developed to the testosterone-depleting effects of these drugs. Acute treatment with morphine also lowered serum luteinizing hormone levels, and this reduction preceded the fall in testosterone levels by 1 to 2 hours.

Animals↗
PubMed1975

Function of the male sex organs in heroin and methadone users.

The function of the secondary sex organs was found to be markedly impaired in 29 participants in a methadone maintenance program. The ejaculate volume and seminal vesicular and prostatic secretions were reduced by over 50 per cent in methadone clients, as compared to 16 heroin addicts and 43 narcotic-free controls. Serum testosterone levels were also approximately 43 per cent lower in methadone clients than in controls or heroin users. Although the sperm count of methadone clients was more than twice the control levels, reflecting a lack of sperm dilution by secondary-sex-organ secretions, the sperm motility of these subjects was markedly lower than normal. On all measures of secondary-sex-organ and testicular function, heroin addicts appeared to fall between the methadone and control subjects, but, with the exception of sperm motility, the deviation from control values did not reach statisitcal significance.

Adult↗