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Biomedical subjects

R Martin

Publications and source records attributed to R Martin.

At least 721 records · Page 40Linked to original sources
PubMed1975

The primary structure of tRNAIIArg from brewers' yeast. 1. Complete digestions with pancreatic and T1 ribonucleases.

tRNAIIArg purified from bulk brewers' yeast tRNA by countercurrent distribution followed by two column-chromatographic steps was completely digested with pancreatic and T1 ribonucleases. Isolations of the products have been carried out either by column chromatography or by high-voltage electrophoresis. Analyses of the isolated nucleotides and olignoucleotides were in good agreement and indicate that this tRNA is composed of 76 nucltotide residues including 13 minor nucleotides. Overlaps resulting from the end-products of the two complementary digests led to a sequence of 25 residues. The primary structure of tRNAIIArg has been determined after partial digestion with T1 ribonuclease as described in the following paper.

Arginine↗
PubMed1975

Dose and treatment factors in radiation-related pericardial effusion associated with the mantle technique for Hodgkin's disease.

A retrospective study of 83 patients with Stage I-III Hodgkin's disease treated with an upper mantle field revealed a rate of radiation-related pericardial effusion (RRP) of 28.9% (24/83). Clinical presentation was asymptomatic effusion in 10/24 and symptomatic effusion in 14/24. RRP was self-limited in all but 4 patients, who progressed to chronic effusion requiring pericardiectomy (4/24). A midplane mediastinal dose of 4000 rads in 4 weeks was given with an anteriorly weighted mantle field that resulted in an average pericardial dose of 5325 rads (1823 ret) and an average midplane cardiac dose of 4625 rads (1558 ret). The rate of RRP was correlated with increasing degree of mediastinal Hodgkin's disease. Increased incidence of RRP with increasing cardiac and pericardial dose could not be proven statistically. Factors which may facilitate pericardial effusion following a basic radiation injury are discussed.

Hodgkin Disease↗
PubMed1975

A presynaptic complex in the giant synapse of the squid.

A presynaptic complex consisting of thin lamellae associated with vesicles was found frequently in presynaptic terminals of the squid giant synapse. The lamellae, made of osmiophilic material, had an average length and width of about 10 mum and a thickness of 30 nm; they were of rectangular shape. While most frequent in the axoplasm of the most distal, and largest, terminal of the presynaptic giant axon, the lamellae were found also in smaller terminal branches of this fibre; They have not been observed in the proximal parts of the presynaptic or postsynaptic giant axons. Vesicles the size of synaptic vesicles surrounded the sides of the lamellae. The presynaptic complex resembles the synaptic ribbons in sensory cells.

Animals↗
PubMed1975

Punishment and negative reinforcement of stuttering using electric shock.

Five adult male stutterers were subjected to electric shock under three conditions. After stuttering frequency was stable in base rate, three subjects were (1) presented electric shock continuously, but the shock was terminated for five seconds contingent on each stuttering (escape); (2) not presented electric shock continuously, but were given a burst of shock contingent on each stuttering (punish); and (3) allowed to choose the shock condition they preferred. Two other subjects followed the same procedure, except that the order of the escape and punish conditions was reversed. The five subjects behaved differently in the various experimental conditions. For three subjects, the percentage of words stuttered changed very little in the escape condition, whereas two subjects' stuttering increased in escape. In the punish condition, the percentage of words stuttered changed very little for one subject, increased for two subjects and decreased for two subjects. Little change in stuttering behavior occurred in the preferred choice condition.

Adult↗
PubMed1975

Comparison of the effects of ethinyl oestradiol and conjugated equine oestrogens in oophorectomized women.

Seventeen oophorectomized women were treated for 3 month periods, in random sequence, with ethinyl oestradiol 20 and 50 mug daily and conjugated equine oestrogens (Premarin)0-625 and 1-25 mg daily. The serum cholesterol, clot lysis time, plasma fibrinogen, platelet adhesiveness and activated partial thromboplastin time remained unchanged throughout the different oestrogen regimes. There was a significant rise of serum triglyceride levels on both doses of ethinyl oestradiol but no significant change with Premarin. Serum luteinizing hormone levels were depressed most by ethinyl oestradiol 50 mug daily, although no down to the levels in premenopausal women.

Adult↗
PubMed1975

Role of inertia in the measurement of dynamic compliance.

Dynamic compliance (Cdyn) was measured at different frequencies (breaths/min) in 30 nonsmoking males and females aged 30-59 yr. In those aged 30-49 yr Cydn at 90 breaths/min was significantly higher than at 15 breaths/min while those aged 50-59 yr showed no significant difference. Assuming an inertance of 0.01 cmH2O/l per s-2, and a sinusoidal breathing frequency, Cydn at 60 and 90 breaths/min was corrected for inertia. In the 30-49 yr age group corrected Cydn did not change with increasing frequency of breathing whereas in the 50-59 yr age group Cydn at 15 breaths/min was significantly higher than at 90 breaths/min (P is less than 0.05). In this age group, four of eight subjects were frequency dependent when corrected for inertia. These findings indicate that inertia influences Cydn at breathing frequencies of 60 per min and above. Unless this is taken into account, frequency dependence of compliance may be missed. The results also indicate that frequency dependence of compliance is normal in some older individuals but is not normal in the younger age group.

Adult↗
PubMed1975

The Use of a Helium-Oxygen Mixture during Maximum Expiratory Flow to Demonstrate Obstruction in Small Airways in Smokers.

We measured the response to breathing a mixture of 80% helium and 20% oxygen (He) during a maximum expiratory flow-volume (MEFV) maneuver in 66 nonsmokers and 48 smokers, aged 17-67. All of the subjects studied had (forced expiratory volume in 1 s/forced vital capacity [FEV(1.0)/FVC]) x 100 of greater than 70%. While the flow rates of the smokers were within +/-2 SD of those of the nonsmokers at 50% VC (Vmax(50)), both groups showed a reduction in flow with age (nonsmokers: r=-0.34, P<0.01; smokers r=-0.52, P<0.001). Nonsmokers showed no significant reduction with age in response to breathing He, while smokers showed a marked reduction with age (r=-0.63, P<0.001 at Vmax(50)). We also measured the lung volume at which maximum expiratory flow (Vmax) while the subject was breathing He became equal to Vmax while he was breathing air, and expressed it as a percent of the VC. This was the most sensitive method of separating smokers from nonsmokers. These results indicate that the use of He during an MEFV maneuver affords sufficient sensitivity to enable detection of functional abnormalities in smokers at a stage when Vmax while they are breathing air is normal.

Journal Article↗
PubMed1975

[Hyperthermia in the rabbit. I. Studies on influencing circulation with exogenic hyperthermia].

Increasing the environmental temperature to 35 degrees C produced hyperthermia in 11 female rabbits, 80-90 days old. At the onset of hyperthermia the heart rate increased, but there was no further change after about two hours (range 1-3 hours); it remained constant at an increased rate until the end of the experiment. Blood pressure fell at first, but it had increased again after 90 minutes, and underwent no further change during the experiment. The mechanism of these circulatory changes were discussed in relation to the neutral control of body temperature regulation.

Animals↗
PubMed1975

[Hyperthermia in the rabbit. II. Studies on influencing respiration with exogenic hyperthermia].

Rectal temperature, respiratory rate, arterial and venous pH and arterial and venous pCO2 were recorded at intervals of 15-30 minutes in female broiler rabbits exposed an environmental temperature of 35 degrees C, until they died. Respiratory rate and blood pH rose, and pCO2 fell, until a rectal temperature of 42 degrees C was reached. Upon further increase in rectal temperature the respiratory rate and pH began to fall, while pCO2 began to rise. The rabbits died when rectal temperature reached 43 degrees C. Features of respiratory function peculiar to the rabbit were discussed.

Animals↗