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Biomedical subjects

R Smith

Publications and source records attributed to R Smith.

At least 1,513 records · Page 84Linked to original sources
PubMed1977

Correlation of clinical, biochemical and skeletal responses to 1alpha-hydroxyvitamin D3 in renal bone disease.

Thirty-five patients with bone disease and chronic renal failure (twenty-four on maintenance haemodialysis) were treated for 7--39 months with 1alpha-hydroxyvitamin D3, 2--2.5 microgram daily by mouth. Symptoms (bone pain and muscle weakness) and radiographic appearances improved and plasma alkaline phosphatase returned to normal in the majority of patients (87, 76 and 75% respectively). In contrast, histological appearances in bone improved in only 46% twenty-three patients from whom paired biopsies were available, and this change was not greatly different from that seen in a comparable group of untreated patients. Significant correlations were noted in individual patients between the changes in symptoms, X-rays, plasma alkaline phosphatase and immunoreactive parathyroid hormone and these, in turn, were related to histological changes in bone, although these latter changes were often small. It is concluded that 1alpha-hydroxyvitamin D3 is a useful new drug in the treatment of renal bone disease, but that the evaluation of the response depends critically on the method of assessment used.

Adolescent↗
PubMed1977

Factors influencing the response to 1alpha-hydroxyvitamin D3 in patients with renal bone disease.

Twenty-three patients with bone disease and chronic renal failure were treated for periods of 4--28 months with 1alpha-hydroxyvitamin D3 (1alpha-OHD3). Improvements in bone histology were consistently seen in patients with features both of osteitis fibrosa and osteomalacia but were not invariably observed in patients with osteitis fibrosa or osteomalacia alone (37 and 50% improved respectively). Several factors influencing the outcome of treatment were assessed on the basis of histological responses in bone. A low level of plasma calcium before treatment, rather than the dose of 1alpha-OHD3 tolerated, was the major detectable factor which favourably affected the histological outcome. Other factors examined, including initial plasma concentrations of phosphate, immunoreactive parathyroid hormone and alkaline phosphatase, and treatment with haemodialysis or dietary supplements of calcium did not apparently influence the response.

Alkaline Phosphatase↗
PubMed1977

Physiological and therapeutic differences between vitamin D, its metabolites and analogues.

Since several metabolites and analogues of vitamin D have become available, their physiological and therapeutic potential have been studied in various disorders of mineral metabolism, particularly those classically termed vitamin D-resistant. In some instances this resistance appears to be due to defective metabolism of vitamin D or to defective target organ responses, but in others it is not. Although the precise effect of vitamin D or its metabolites on mineralization of bone is still unknown there is some evidence that the metabolites differ in their relative effects on intestine, bone, muscle and parathyroid glands. These differences may eventually have therapeutic value. At present the major advantage of 1alpha-hydroxylated derivatives of vitamin D over other compounds resides in their more rapid onset and reversal of action which makes them much easier and safer to use.

Bone Resorption↗
PubMed1977

Biochemical measurements in Paget's disease of bone.

In a group of eighty-three patients with untreated Paget's disease of bone, plasma alkaline phosphatase activity (AP), plasma non-protein-bound hydroxyproline concentration (PHP) and urinary excretion rate of total hydroxyproline (THP) were closely correlated with each other but not with fasting plasma concentrations of calcium or inorganic phosphate. Probit plots of AP and THP showed log-normal distributions overlapping the normal ranges.

Adult↗
PubMed1977

Renal osteodystrophy in nondialysed adolescents. Long-term treatment with 1alpha-hydroxycholecalciferol.

The effects of small oral doses (1-2 microgram/day) of 1alpha-hydroxycholecalciferol, given for 1 to 2 years, have been examined in four nondialysed adolescents with chronic renal failure and bone disease. Treatment increased calcium retention and plasma calcium, and decreased plasma levels of alkaline phosphatase, hydroxyproline, and immunoreactive parathyroid hormone. X-ray abnormalities of bone regressed, and 2 patients underwent successful surgical correction of knock-knees; bone histology in these 2 was normal at the time of operation. 2 patients developed hypercalcaemia which promptly reversed when 1alpha-hydroxycholecalciferol was withdrawn. In one patient treatment was initially successful, but later there was biochemical, radiographic, and histological evidence of relapse. Long-term treatment of such patients with 1alpha-hydroxycholecalciferol may be effective and facilitate the surgical correction of deformities, but this is not invariable. Toxic effects are similar to those of vitamin D itself, but are more readily reversible.

Adolescent↗
PubMed1977

Cystinotic rickets treated with vitamin D metabolites.

A 22-month-old girl with cystinotic rickets was given 1 microgram 1,25-dihydroxycholecalciferol (1,25-DHCC) daily in addition to standard treatment. Her rickets healed and linear growth rate appeared to increase. It is suggested that the effect of 1,25-DHCC and its metabolically active analogues on cystinotic rickets should be further studied.

Cystinosis↗
PubMed1977

Fetal exposure to 1:8 dihydroxyanthraquinone.

A survey of 160 consecutive maternity cases showed that a high percentage of mothers had exposed their fetus to laxatives of the anthraquinone type at some stage during the pregnancy. Administration of 1:8 dihydroxyanthraquinone at the time of induction of labour with estimation of the substance in maternal urine, amniotic fluid and the first urine obtained from the baby, indicated that the substance is absorbed from the maternal gut, crosses the placenta and is excreted via the fetal kidney into the liquor. In mothers and babies most of the drug appeared as glucuronide. Fetal catharsis did not appear to occur and the reasons for this are discussed.

Anthraquinones↗
PubMed1977

Tympanic membrane keratoma (cholesteatoma) in children with no prior otologic surgery.

Three children whose eardrums appeared normal upon previous examinations, one with the otomicroscope, apparently developed tympanic membrane cholesteatomas that penetrated the fibrous layer of the pars tensa. Their histories all included episodes of acute otitis media, but no otorrhea. No otologic surgical procedures, including myringotomy, had been performed. These cases are thought to provide clinical support for the basal epithelial migration theory of cholesteatoma genesis. Rüedi's experiments suggest that cholesteatomas resulting from basal epithelial migration may not be visible for 18 to 30 days; thus, follow-up evaluations after acute otitis media should probably include examinations one and two months after the infection. Pediatricians and family physicians should be urged to seek otologic consultation for patients with even minor eardrum abnormalities, particularly those following infection.

Child, Preschool↗
PubMed1977

Comparison of the bronchodilator effects of oral therapy with fenoterol hydrobromide and ephedrine.

Fenoterol hydrobromide (Berotec; formerly Th 1165a) is a sympathomimetic bronchodilator drug. Twenty subjects with mild to moderate reversible bronchospasm completed a double-blind multiple crossover study of single doses of 5 mg, 7.5 mg, and 10 mg of fenoterol hydrobromide, 24 mg of ephedrine, and placebo. Spirometric and body-plethysmographic measurements were performed sequentially prior to administration of drug or placebo and each hour up to eight hours afterwards. No significant drug-response relationship was noted for pulse rate or blood pressures, and side effects (eg, shakiness, nervousness) were minimal. Administration of fenoterol resulted in bronchodilation; a peak effect was noted at two to three hours after administration, and the duration of action was up to eight hours. A statistically significant dose-response relationship was observed; therapy with 5 mg of fenoterol hydrobromide was superior to placebo and equal to ephedrine, and doses of 7.5 mg and 10 mg of fenoterol hydrobromide were significantly better than placebo or ephedrine.

Administration, Oral↗
PubMed1977

Comparison of the bronchodilator effects of aerosol fenoterol and isoproterenol.

Aerosolized fenoterol in a dosage of 400 microgram was compared to isoproterenol 150 microgram in 31 asthmatic subjects during the course of a double-blind parallel 90-day study. Bronchodilator activities of the two drugs were evaluated for up to 6 hours on days 1, 45 and 90. Analysis of the data revealed that fenoterol consistently produced a significantly greater increase in FEV1, FEF25-75% and Gaw/VL. Specific airway conductance increased on each test day 25 percent or more above baseline for over three hours after use of fenoterol and for only one hour after use of isoproterenol. Fenoterol has less effect upon the cardiovascular and central nervous systems, but produced a greater incidence of shaking compared to isoproterenol. Patients used fenoterol less frequently than isoproterenol which can be attributed to the former having a greater peak effect and time course of bronchodilation. The therapeutic efficacy of fenoterol was sustained throughout this three-month study, and suggests that this relatively selective beta2 adrenergic drug will provide a well tolerated, alternative aerosol for chronic use in asthma.

Adult↗
PubMed1977

Pretreatment of cadaver donors with methylprednisolone in human renal allografts.

Fifty cadaveric kidney donors were randomly allocated to two groups. Group 1 received 5 grams of intravenously administered methylprednisolone two to four hours prior to organ harvesting after the pronouncement of brain death. Group 2, which served as the control group, received no pretreatment. Of 100 kidneys harvested, 16 were discarded for various reasons, and 84 were transplanted and were available for evaluation, 40 from the pretreatment group and 44 from the control group. The transplant centers using these kidneys were unaware of the status of the kidney they received, that is, whether it was from a pretreated or a control group. The two groups of kidneys, pretreated and control, did not differ according to the length of warm or cold ischemia time or presence of preformed cytotoxic antibodies. The difference in graft failure between the two groups at three months was insignificant, even when the two groups were compared according to the method of preservation used.

Antibody Formation↗
PubMed1977

Factors affecting the time of formation of the mouse blastocoele.

In normal mouse embryos developing in vivo, the first appearance of the blastocyst cavity was found to be associated more closely with developmental age, judged by cell number, than with chronological age, i.e. elapsed time since ovulation. When development was slowed by in vitro culture, formation of the blastocoele was delayed. However, cell number itself was not a critical factor, since the number of cells per embryo could be doubled or tripled or halved by experimental manipulation without substantially affecting the timing of blastocoele formation. Experiments in which one cell division was suppressed with cytochalasin-B, leading to tetraploidy, showed that the number of cell divisions since fertilization was also not critical. A possible role is suggested either for nucleocytoplasmic ratio, or for the number of nuclear or chromosomal divisions or DNA replications since fertilization, all of which increase during cleavage.

Animals↗