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Biomedical subjects

M R Lee

Publications and source records attributed to M R Lee.

At least 145 records · Page 8Linked to original sources
PubMed1982

Reversible developmental change in the ability of ciliary ganglion neurons to extend neurites in culture.

From stages 35 to 40 in the chicken embryo, ciliary ganglion neurons undergo a developmental change which is detected in our assay system as a marked decline in the ability to extend neurites when placed in culture. This developmental loss is observed when the neurons are placed in culture as single, dissociated cells or as undissociated ganglion explants. The loss of the ability to extend neurites in culture is not a transitory phenomenon, for no recovery of this ability is observed during the rest of embryonic development or posthatching. There is a close temporal correlation between the embryonic period during which the ability of ciliary ganglion neurons to extend neurites declines and the period (stages 35 to 40) when these neurons form functional peripheral synapses in the embryo. The ability to extend neurites rapidly is not recovered during normal development as long as the ganglion and its connections within the organism remain intact. However, if the ciliary ganglia are removed from a stage 40 embryo and cultured for 3 to 4 days before being dissociated, the neurons have largely recovered their ability to initiate neurite outgrowth rapidly. This recovery after removal from the embryo is also presumably responsible for the eventual dense outgrowth of neurites from stage 40 ganglion explants after a 3- to 4-day delay in culture. Our results, in conjunction with similar results from other systems, suggest a cause and effect relationship between the establishment or disruption of peripheral connections and the loss or recovery, respectively, of the ability to extend neurites rapidly.

Animals↗
PubMed1981

Urine free dopamine in normal primigravid pregnancy and women taking oral contraceptives.

1. Urine free dopamine was estimated at predetermined points of the menstrual cycle in normal volunteer subjects and in women taking a combined oral contraceptive. 2. There was no alteration in 24 h urine dopamine during the normal menstrual cycle but, in contrast, combined oral contraceptives produced a fall which recovered premenstrually. 3. In 19 primigravid subjects 24 h urine free dopamine was estimated at monthly intervals throughout pregnancy and at the time of the postnatal examination. 4. Urine dopamine was elevated throughout pregnancy when compared with postnatal values. Women receiving an oral progestogen contraceptive at the time of the postnatal examination showed a further fall in urine dopamine.

Adult↗
PubMed1981

Biochemical indices of response to hydroxychloroquine and sodium aurothiomalate in rheumatoid arthritis.

Biochemical and clinical changes have been monitored in 30 patients with rheumatoid arthritis treated with either hydroxychloroquine or sodium aurothiomalate over a period of 6 months. Acute-phase reactants improved in both treatment groups, while serum sulphydryl and serum histidine improved only in the gold-treated patients. Correlation matrices were constructed from mean clinical and biochemical data at successive clinic visits. Correlations obtained with gold were more frequent and of a higher level of significance than those obtained with hydroxychloroquine at the doses we studied. This lends support to the use of correlation matrices as a screening test for potential long-term antirheumatoid activity of drugs in man.

Adult↗
PubMed1981

The treatment of idiopathic orthostatic hypotension: a combined fludrocortisone and flurbiprofen regime.

We report our experience in the management of idiopathic orthostatic hypotension using the prostaglandin synthetase inhibitor, flurbiprofen. In five subjects with proven autonomic failure the effect on blood pressure of the addition of flurbiprofen (or fludrocortisone) to the previous drug regime was assessed. Both lying and standing blood pressure were seen to rise with fludrocortisone treatment although the change in standing blood pressure was not statistically significant. Flurbiprofen, in contrast, produced no change in lying blood pressure but a significant rise in standing blood pressure. Digital blood flow measurements were made on three subjects before and after flurbiprofen and a dose-related reduction in post-occlusive reactive hyperaemia was demonstrated suggesting an effect of this drug on precapillary smooth muscle tonus. Two patients failed to maintain a long-term response to treatment with flurbiprofen and fludrocortisone but have been helped by the addition of I) ephedrine or II) tyramine an monoamine oxidase inhibitor (phenelzine). We recommend a stepwise approach to treatment in this condition commencing with flurbiprofen and adding fludrocortisone later if necessary. This approach would appear to offer the maximum benefit with a minimum of side effects.

Adolescent↗
PubMed1980

The effect of mineralocorticoid administration on urine free dopamine in man.

1. Five normal subjects were studied under metabolic conditions on a controlled sodium and potassium intake. 2. Plasma and urine free dopamine concentrations were measured in these subjects before, during and after 5 days administration of fludrocortisone (0.2 mg twice daily). 3. Urine free dopamine showed a tendency to fall during the early phase of fludrocortisone administration and then rose towards normal. 4. In a patient with primary hyperaldosteronism there was no evidence of increased renal production of dopamine. Urine dopamine fell when plasma renin activity rose as a result of spironolactone administration (200 mg three times a day for 5 days). 5. If renal dopamine has a role in mineralocorticoid 'escape' then it may be permissive only. The mechanisms of control of dopamine production could include tubular sodium concentration, tubular chloride concentration and intrarenal renin activity.

Adult↗
PubMed1980

A biochemical comparison of alclofenac and D-penicillamine in rheumatoid arthritis.

In view of the claim that alclofenac has a specific antirheumatoid action a detailed biochemical study has been made over a 6-month period of 2 groups of patients with rheumatoid arthritis receiving either alclofenac or D-penicillamine for the first time. We found no biochemical evidence and little clinical evidence that alclofenac had a 'penicillamine-like' effect in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1980

Discriminatory indices of response of patients with rheumatoid arthritis treated with D-penicillamine.

A long-term study is being undertaken to classify drugs used as specific agents in the treatment of rheumatoid arthritis in terms of their effects on biochemical and clinical characteristics of the disease. In particular is hoped to establish those indices which are most relevant to the response of RA to treatment. Fifteen patients were treated with D-penicillamine after an initial period of 2 weeks on aspirin alone, when the baseline investigations were made. The dose of penicillamine was increased gradually to a maximum of 500 mg a day over the period of 6 months, and changes in 8 clinical and 25 laboratory indices were measured on 8 separate occasions in the 6-month period. Marked clinical improvement took place, and this was mirrored by changes in a wide range of biochemical parametaers. ESR and C-reactive protein were shown to be the most suitable indices of disease improvement with penicillamine treatment.

Adult↗
PubMed1980

Yeast stimulation of bone marrow mitosis for cytogenetic investigations.

We report a simple, dependable method for stimulating bone marrow mitosis in small mammals. Subcutaneous injections of a suspension of active baker's yeast may elevate the mitotic index as much as six times or more. Additionally, the metaphases obtained are easily spread when air dried, and the chromosomes are readily banded. This method should prove useful to investigators who wish to use bone marrow as a source of chromosomes for cytotaxonomic studies or for studies of specific chromosome damage in vivo.

Animals↗
PubMed1980

Mastomys (=Praomys) natalensis is not a Rattus (Mammalia: Rodentia): karyological evidence.

Certain past studies have suggested that the taxa Mastomys (= Praomys) and Rattus were closely allied phyletically. We here present detailed (C- and G-banding and NOR's) comparisons of the karyotypes of M. natalensis (2n = 36) and R. norvegicus (2n = 42). A standardized G-banded karyotype of M. natalensis is also presented. About 45% of the G-banded karyotype of M. natalensis is homologous with that of R, norvegicus. Autosomal constitutive heterochromatin is nearly equivalent in the two species; the X and Y chromosomes of M. natalensis, however, have exceptionally large heterochromatic segments. Both species possess three pairs of NOR's, but adjacent G-banded regions are homologous for only one of these. Primarily on the basis of overall G-band homology, we regard the two taxa as only distantly related.

Animals↗
PubMed1980

A comparative trial of fixed ratio beta-adrenoceptor blocker and diuretic combination products in moderate hypertension.

Two fixed ratio combination tablets, 10 mg pindolol combined with 5 mg clopamide and 100 mg metoprolol combined with 12.5 mg hydrochlorothiazide, were compared at two dose levels in a double-blind crossover trial in 10 previously untreated hypertensive patients. No significant difference was observed between resting blood pressure on the two combinations at either dose level. Exercise systolic pressure was lower after the pindolol/clopamide combination at low dose (p less than 0.05). The incidence of side-effects in this trial was high but proper comparison of the two products could not be made because of the small number of patients. It is suggested that combination products should be used only after patients have failed to respond adequately to a single agent.

Adrenergic beta-Antagonists↗
PubMed1979

Plasma and urine dopamine in man given sodium chloride in the diet.

1. Plasma and urine free dopamine were measured daily for 5 days in six normal subjects maintained on a low sodium diet. The subjects were then given dietary supplements of sodium chloride for 5 days and the measurements repeated. 2. Throughout the experiment the 24 h free dopamine excretion rates for all the subjects were higher than could be accounted for by renal clearance. Dopamine excretion increased significantly in response to the added sodium chloride whereas plasma dopamine remained unchanged. The rise in dopamine excretion preceded that of sodium excretion. 3. It is concluded that free dopamine is formed within the kidney in response to increased dietary sodium and may have a role in the control of sodium excretion.

Creatinine↗
PubMed1979

Two cases of the nephrotic syndrome with a reversible coagulation defect.

Two cases of the nephrotic syndrome with an apparently identical defect of blood coagulation, discovered during preparation for renal biopsy are described. Plasma from both patients showed prolongation of thrombin and kaolin cephalin times which was probably due to abnormally slow polymerization of fibrin monomer. Corticosteroid therapy reversed the abnormal times in one case. One of the patients showed seasonal relapses which occurred in relation to episodes of hay fever associated with allergy to grass pollen. The other patient showed some similar features, but on renal biopsy was found to have proliferative glomerulonephritis.

Adult↗