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Biomedical subjects

B Martin

Publications and source records attributed to B Martin.

At least 433 records · Page 24Linked to original sources
PubMed1980

Effects of ethanol on protein synthesis and secretion.

Liver protein synthesis involves a complex series of reactions which is influenced by hormones, nutritional state and general health of an animal. The secretory processes for proteins, such as albumin, also interact with the protein synthetic machinery of the liver. Alcohol may affect synthesis and/or secretion at a number of loci and the mechanism of alcohol's action could depend on the immediate state of the experimental tissue. Ethanol was shown to interfere with albumin synthesis and the effect was shown to differ when livers from fed and fasted animals were compared. The ethanol effects were also dependent on the metabolism of ethanol rather than on the simple presence of this drug. Acetaldehyde decreased albumin synthesis but in a manner which was distinct from the ethanol effect. Acute ethanol administration under the conditions used in our studies had little effect on secretion of prelabeled proteins from hepatocytes. The implications of studies of the effects of ethanol on liver protein synthesis and secretion are discussed.

Acetaldehyde↗
PubMed1980

Effects of dietary fat and alpha-tocopherol on gamma-glutamyltranspeptidase activity of 7, 12-dimethylbenz(alpha)anthracene-induced mammary gland adenocarcinomas.

The levels of gamma-glutamyltranspeptidase (GGTP) (EC 2.3.2.2) were measured in 7, 12-dimethylbenz(alpha)anthracene-induced mammary adenocarcinomas, in control mammary gland tissue and in sera from tumor-bearing and control rats. The carcinogenic process was modulated by diets differing in the type and amount of fat with and without alpha-tocopherol supplementation. Rat mammary adenocarcinomas showed significantly elevated (up to 25-fold) levels of GGTP when compared with adjacent histologically-uninvolved tissue or with mammary tissue of control rats. GGTP activity in sera from tumor-bearing rats was also elevated up to 4-fold than in the corresponding controls. Histochemical studies of the frozen section of mammary adenocarcinomas indicated that GGTP was localized in neoplastic ductal epithelial cells. In tumor rats on alpha-tocopherol supplemented diets, GGTP activity in the adenocarcinomas was mainly in the particulate (membrane-bound) fraction. In contrast, the tumor rats receiving alpha-tocopherol-deficient diets, the total GGTP activity was distributed in both particulate and cytosolic fractions, suggesting an altered membrane-GGTP interaction. The levels of GGTP in control mammary gland and sera of control rats from the low fat dietary groups were up to 7-fold higher than the corresponding control values in either of two high-fat groups. These high levels of GGTP in the serum and tissues of animals from the low fat dietary group are consistent with lower tumor incidence through enhanced carcinogen detoxification.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Effects of whole-body vibration on spinal reflexes in man.

Recent studies have described sensory-motor function alterations resulting from vibrations applied to various parts of the body. The present work describes the effects produced at the myotatic loop level by long-term vibration. Hoffmann and Tendon reflexes as well as tendon vibration response were substantially depressed by 18 Hz, +/- 0.25 G vibration applied to the whole body or to the legs of seated human subjects. The reflex inhibition lasted throughout the 15-min vibration period and persisted minutes after stimulus cessation. In contrast, vibration limited to the S's head and trunk showed much weaker effects. This suggests that the vibration acts mainly upon extero- and proprioceptive receptors rather than upon the vestibular organs. The results are discussed in relation to findings derived from experiments involving locally applied short-duration vibration.

Adolescent↗
PubMed1980

Acute hypocalcemia and erythropoiesis in the mouse.

Mice were made acutely hypocalcemic by injection of sodium oxalate. After the transient drop of plasma calcium marked changes in erythroblastic proliferation, number of erythroblasts and 59Fe kinetics were observed. The probable mechanism of this response that may reflect increased erythropoiesis is discussed.

Acute Disease↗
PubMed1979

Effect of dicarboxylic acids on lentigo maligna.

Dicarboxylic acids from C8 to C14 are competitive inhibitors of tyrosinase in vitro, and here, the effect of a cream containing 15% azelaic acid (C9) on 3 cases of lentigo maligna is described. The lesions were treated for 90 days, with remarkable clinical and histological effect, maintained for up to 2 yr after cessation of treatment. Progress during treatment of one case was additionally monitored by electron microscopy, which revealed progressive elimination of abnormal melanocytes both basally and suprabasally, and their replacement by essentially normal cells engaged in normal melanogenesis. There was also progressive diminution in the general disorganization of the epidermis, and disappearance of lymphocyte response. It is concluded that dicarboxylic acids have a direct inhibitory and cytotoxic effect on abnormally active or structurally disordered melanocytes in lentigo maligna, but further investigations are required to establish their precise mode of action. Similar application of dicarboxylic acids to normal skin affects only a small proportion of melanocytes, suggesting that some phasic factor, or individual states of activity, may be concerned in their susceptibility.

Aged↗
PubMed1979

Effect of dicarboxylic acids on normal human melanocytes in dispersed tissue culture.

Since dicarboxylic acids are competitive inhibitors of tyrosinase, and effective in treatment of hyperpigmentary disorders, such as chloasma and lentigo maligna, probably due to a cytotoxic effect on abnormal melanocytes, it is of interest to examine their effect on normal melanocytes in tissue culture. Azelaic or dodecandioic acids were added (150-200 micrograms/ml) to dispersed cultures of epidermal cells, and melanocytes were examined by electron microscopy after 7, 10, 15, 20 and 30 days. Apart from a stimulation of melanogenesis, the presence of dicarboxylic acids in the culture medium caused no detectable damage to melanocytes, nor did they prevent growth of a second generation of cells.

Culture Techniques↗
PubMed1979

Visual acuity following retinal detachment surgery.

A poor visual acuity following an anatomical cure of a retinal detachment was in this series always associated with a change in macular morphology, the commonest maculopathy being the appearance of a cellophanemembrane. Factors influencing the visual prognosis are duration and extent of the detachment, involvement of the macula, the age of the patient and the presence of pre-operative periretinal membrane formation. The type of buckling procedure is not related to the visual outcome and while the conversion of the procedure into an intra-ocular operation, either by way of drainage of subretinal fluid or by intra-vitreal injection, can cause serious complications we suggest that uncomplicated drainage of subretinal fluid has not been a cause of macular pucker in this series but that this conditions is related to the indication for drainage, namely a varying degree of rigidity of the retina due to periretinal membrane formation.

Age Factors↗
PubMed1979

Central retinal vein occlusion in a patient with familial antithrombin III deficiency: case report.

A 60-year old man with familial antithrombin III deficiency, a primary cause of hypercoagulation, developed central retinal vein occlusion. Familial antithrombin III deficiency is inherited as an autosomal dominant condition. It is characterized by recurrent episodes of thromboembolism. The occurrence of central retinal vein occlusion in a person with familial deficiency of antithrombin III suggests the possibility of a casual relationship.

Animals↗
PubMed1978

Modification of problem interation in mother-child dyads by modeling and behavior rehearsal.

Eighteen mother-child dyads who previously had reported difficulties in solving problems were assessed behaviorally in situations in which they attempted to resolve conflicts. Half the dyads then were given two treatment sessions that consisted of modeling and rehearsal designed to improve their skills in resolving problem situations. In the pretest assessment a number of significant correlations between mother and child responses were found. Notably, when mothers blamed or used direct arbitrary power with their children, the children in turn emitted oppositional behaviors, but when the mothers made tentative proposals, their children reciprocated with positive responses. In the posttest assessment, treatment mothers employed the expression of feelings to their children as a conflict resolution strategy significantly more often than did control mothers. There was also a tendency for the treatment children to acquiesce less to their mothers' demands than did control children in the problem situations.

Adult↗