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Biomedical subjects

B Martin

Publications and source records attributed to B Martin.

At least 379 records · Page 21Linked to original sources
PubMed1984

C21 steroids and transcortin-type protein during delayed implantation in the European badger Meles meles L.

A high-affinity corticosteroid-binding protein (CBG) roughly resembling a transcortin-type protein is present in badger plasma. Plasma CBG, corticosteroid and progesterone (P) concentrations were measured in relation to delayed implantation, true progestation and gestation. Two significant CBG increases were observed during pregnancy. The first, in the second half of embryonic diapause coincides with an increase in plasma corticosteroid concentration and the second, during true progestation and gestation, with an increase in P concentration. Relationship of CBG increases with pregnancy in badger are discussed.

Adrenal Cortex Hormones↗
PubMed1984

Evidence for an intracellular precursor for human B-cell growth factor.

Human B-cell growth factor has been described as a trypsin-sensitive protein of Mr 12,000-14,000. Evidence is provided herein that this relatively low molecular weight product may be released from a larger precursor molecule of Mr 60,000-80,000. The precursor protein is confined to the cytosol of freshly isolated T lymphocytes, and only the Mr 12,000-14,000 moiety is released upon lectin stimulation. The precursor protein was subjected to limited tryptic digestion, which demonstrated that the biologically active fraction of the moiety resided in a relatively low molecular weight fragment. The T lymphocyte routinely possessed an intracytoplasmic pool of the precursor protein, the amount of which cyclically varied depending upon its depletion by the secretion process of a lower molecular weight product. Analysis of the mRNA size coding for the majority of B-cell growth factor activity, determined by translation in Xenopus laevis oocytes, suggested that the B-cell growth factor-specific mRNA resided in the greater than or equal to 15S range. This value is consistent with the size of the larger precursor. Therefore, it is proposed that a precursor-product relationship exists for the processing of human B-cell growth factor, analogous to that which has been described for several other cytokines.

Animals↗
PubMed1984

Fetal responses to vibrotactile stimulation, a possible predictor of fetal and neonatal outcome.

This study measured the antenatal fetal heart rate changes in response to a single vibrotactile stimulus. In a group of 11 normal patients, this resulted in a significant change in the fetal heart rate (P less than 0.001). Sixty-eight high risk patients were also tested. In the group of 25 patients whose fetuses showed no response to the stimulus, there were 4 stillbirths and 4 neonatal deaths; 23 of these 25 infants were small for gestational age (SGA) compared to only 15 of the 43 that showed a response to the stimulus. Fetal habituation to a repeated vibrotactile stimulus was measured in a control group of 40 patients who had a normal antepartum and intrapartum course and delivered infants in an optimal condition. The same was done in a study group of 48 patients who delivered infants that were SGA. These infants were assessed at 1 year of age by the Griffiths Mental Developmental Scale (GMDS). Infants that were SGA did not differ significantly from the control group. However, infants who had a normal antenatal habituation pattern had a significantly better performance (P less than 0.01) compared to infants who had an abnormal antenatal habituation pattern.

Electrocardiography↗
PubMed1984

Factor analysis and validation of the General Health Questionnaire in men: a general practice survey.

As part of a survey of 1011 men aged 20-60 years, a factor analysis and validation study of the General Health Questionnaire (GHQ) was carried out. Three clinically relevant factors could be isolated but factor analysis did not generally enhance the value of the GHQ. When compared with results for a similar group of women, sex differences in answering the GHQ were found; the GHQ was perhaps a less satisfactory screening instrument in the men.

Adult↗
PubMed1984

Concentration increase of unbound testosterone in plasma of the mare throughout pregnancy.

Blood testosterone levels were measured by RIA and gas chromatography-mass spectrometry in the pregnant mare. They were found to increase from the very beginning of pregnancy, reaching peak values 10 times higher than the basal values at the seventh month and then to return to basal values by the week after parturition. Testosterone binding by plasma proteins was investigated in nonpregnant and pregnant mares throughout gestation. Equilibrium dialysis and gel equilibration methods did not reveal any blood specific testosterone-binding activity at any gestational stage. Hence, blood testosterone increase cannot result as in the pregnant woman or guinea pig, from an increase in blood specific binding activity but more probably results from an increased steroid production. It is suggested that the maternal gonads would be responsible for the testosterone increase in early pregnancy, during the period of PMSG production, and the fetoplacental unit for the subsequent increase.

Animals↗
PubMed1984

Deficient natural killer cell activity in alcoholic cirrhosis.

Natural killer (NK) cell activity against two types of target cells was found to be low in patients with inactive alcoholic cirrhosis (AC). This defect was significantly more pronounced in AC patients with severe malnutrition than in those with mild or moderate malnutrition. This was not due to modifications of the kinetics of NK activity. The sera from AC patients had no inhibitory effect on the NK activity of normal subjects. Lymphocytes and macrophages from AC patients did not exert major suppressive effect on the NK activity of normal subjects. Interferon boosted the NK activity of cells from AC patients, but to a lesser degree than cells from normal controls. The findings show that a deficit of NK activity is clearly associated with inactive AC. This seems to be another consequence of AC on cellular immunity, and might be related to the protein calorie malnutrition often present in AC.

Adult↗
PubMed1984

[Aneurysm of the subrenal abdominal aorta spontaneously rupturing into the inferior vena cava].

The authors report a new case of spontaneous rupture of an infrarenal abdominal aortic aneurysm into the inferior vena cava operated with a good haemodynamic result. However, the patient died of multiple postoperative complications and an associated left bronchopulmonary carcinoma. The following features are emphasised: the contribution of complementary investigations to the diagnosis of this condition: abdominal ultrasonography, aortography and above all, especially in future years, of digitised angiography; the clinical importance of ischaemia of the descending colon and acute postoperative renal failure, the prevention of which should improve surgical results.

Acute Kidney Injury↗
PubMed1984

High-frequency vestibulo-ocular reflex activation through forced head rotation in man.

The dynamic characteristics of the human vestibulo-ocular system were studied in the 0.5-30 Hz frequency range by rotating the head around a vertical axis. The rotation produced by a powerful servo-controlled vibrator was transmitted to the head by a hard-cushioned helmet and a rigid bite bar. The vestibulo-ocular reflex (VOR) gain and phase were measured during fixation of a mobile or stationary visual target and in total darkness. In a second set of experiments, the subjects evaluated the amplitude of the perceived visual instability of the target in the two fixation conditions. The results confirm earlier observations describing the VOR gain and phase in the 0.5-8 Hz range: the gain starts to decrease beyond 2 Hz and the phase rises towards 90 degrees. Beyond 8 Hz, the gain curve reverses direction and increases continuously toward 3-4 at 25-30 Hz in the three tested situations. Meanwhile, the phase curves do not vary much. In the same frequency range, the perceived visual instability is significantly altered. Therefore, the gain variation at high frequency may, in part, explain the perceived visual target instability and may be suspected of altering visually controlled tracking executed in vibrating environments.

Adult↗
PubMed1983

[Torsion of the spermatic cord: diagnosis by Doppler ultrasonography?].

The Döppler ultrasonic examination proposed for the diagnosis of acute painful scrotal syndromes has been used during 4 months. The presence of false negative results in the literature and in the series reported here throws some doubt on the reliability of the method and confirms that systematic surgical exploration remains imperative at the slightest doubt.

Adult↗
PubMed1983

Comparison of Photosynthetic Performance in Triazine-Resistant and Susceptible Biotypes of Amaranthus hybridus.

The rate of CO(2) reduction in the S-triazine-resistant biotype of smooth pigweed (Amaranthus hybridus L.) was lower at all levels of irradiance than the rate of CO(2) reduction in the susceptible biotype. The intent of this study was to determine whether or not the lower rates of CO(2) reduction are a direct consequence of the same factors which confer triazine resistance. The quantum yield of CO(2) reduction was 23 +/- 2% lower in the resistant biotype of pigweed and the resistant biotype of pigweed had about 25% fewer active photosystem II centers on both a chlorophyll and leaf area basis. This quantum inefficiency of the resistant biotype can be accounted for by a decrease in the equilibrium constant between the primary and secondary quinone acceptors of the photosystem II reaction centers which in turn would lead to a higher average level of reduced primary quinone acceptor in the resistant biotype. Thus, the photosystem II quantum inefficiency of the resistant biotype appears to be a direct consequence of those factors responsible for triazine resistance but a caveat to this conclusion is discussed. The effects of the quantum inefficiency of photosystem II on CO(2) reduction should be overcome at high light and therefore cannot account for the lower light-saturated rate of CO(2) reduction in the resistant biotype. Chloroplast lamellar membranes isolated from both triazine-resistant and triazine-susceptible pigweed support equivalent rates of whole chain electron transfer and these rates are sufficient to account for the rate of light-saturated CO(2) reduction. This observation shows that the slower transfer of electrons from the primary to the secondary quinone acceptor of photosystem II, a trait which is characteristic of the resistant biotype, is nevertheless still more rapid than subsequent reactions of photosynthetic CO(2) reduction. Thus, it appears that the lower rate of light-saturated CO(2) reduction of the resistant biotype is not limited by electron transfer capacity and therefore is not a direct consequence of those factors which confer triazine resistance.

Journal Article↗
PubMed1983

Reinforcement and protection with polystyrene of freeze-fracture replicas during thawing and digestion of tissue.

An improved method for reinforcing freeze-fracture replicas, which is especially suitable for tough tissues, is described. For this purpose, polystyrene dissolved in chloroform is used to produce a solid protecting layer of plastic on top of the replica, enabling it to withstand the stresses associated with the thawing and digestion of the tissue with strong acids. The method results in production of large clean replicas from tissues such as skin or peripheral nerve which are difficult to process. The method can also be used profitably for reinforcing other softer and more homogeneous tissues.

Axons↗
PubMed1983

Aphakic retinal detachment. Prophylaxis in the second eye.

One hundred and sixty-three cases of aphakic retinal detachment were reviewed and found to be divided equally between eyes which prior to cataract surgery had been myopic, highly myopic or in a low myope group. Only 30 per cent of the non-myopic eyes had not suffered some form of complication and these eyes constituted only 10 per cent of the whole study. It is concluded that non myopic eyes do not require prophylaxis but that most of the myopes do. Consideration should be given to extra-capsular cataract surgery in addition to prophylactic cryotherapy in the high risk groups.

Aphakia, Postcataract↗
PubMed1983

Depressed polymorphonuclear leukocyte functions associated with normal cytotoxic functions of T and natural killer cells during chronic hemodialysis.

The cytotoxic capacities of T lymphocytes and natural killer (NK) cells and the phagocytic functions of polymorphonuclear leukocytes were determined in a group of 20 patients with end stage disease who were being maintained on hemodialysis. The mononuclear cells from these patients were able to mediate normal T-cytotoxic functions in a xenogeneic cell-mediated lympholysis assay and normal NK cytotoxic capacity when tested against K562 target cells. Contrarily, polymorphonuclear functions in these patients were severely impaired. The reduction of Nitroblue tetrazolium in dark formazan (NBT test) and the direct phagocytosis of 2 pyogenic strains (Staphylococcus aureus and Salmonella typhimurium) were equally and deeply depressed in almost all patients. This defect was not restored either by 4 hr of hemodialysis nor by 12 months of treatment. This study confirms a major role for a defect of polymorphonuclear cell functions in the depressed defence of patients on chronic hemodialysis against infections.

Adult↗
PubMed1983

Comparative pharmacokinetics of antibiotics in newborn calves: chloramphenicol, lincomycin, and tylosin.

The pharmacokinetics of 3 antibiotics--chloramphenicol, lincomycin, and tylosin--were determined in newborn calves. The kinetic determinations, using 2-compartment open models, were made at increasing ages from 1 day to 42 days and compared with those made from 9-month-old calves. Although all 3 antibiotics require a degree of hepatic metabolism, there were marked differences in the development of elimination processes for the individual drugs. Elimination of tylosin, which was slow in the calves at birth, increased rapidly and was equal to that in older calves by the end of 1 week. Lincomycin elimination was not markedly reduced in calves at birth. Chloramphenicol elimination was slow in calves at birth and only by 4 to 6 weeks attained the rate found in older calves. Dosage adjustments would not be required for the antibiotics tylosin or lincomycin when given to newborn calves, but may be necessary for chloramphenicol given to calves before they are 4 to 6 weeks old.

Age Factors↗