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Biomedical subjects

R Martin

Publications and source records attributed to R Martin.

At least 667 records · Page 37Linked to original sources
PubMed1979

Met-enkephaline-like immunoreactivity in a cephalopod neurohemal organ.

Using a highly specific antibody we found Met-enkephalin-like immunoreactivity in large granules of numerous distinct cells that are embedded in a layer of secretory terminals inside the octopus vena cava. Application of antibodies against fragments of the mammalian pro-opiocortin precursor -- alpha-MSH, ACTH, beta-endorphin and 16k-fragment -- and against growth hormone did not produce immunostaining in the octopus enkephalin cells. The vena cava neuropil may represent a favourable system for the examination of the physiological role of the opioid peptide enkephalin.

Animals↗
PubMed1979

Phagocytosis of asbestos fibers by human pulmonary alveolar macrophages.

Human pulmonary alveolar macrophages (PAMs) were cultured for 24--72 h with varying concentrations (0--300 microgram/ml) of amosite asbestos (AS). At lower AS concentrations, (less than 100 microgram/ml) no decrease in cell viability occurred during the first 24 h of culture. Significant cytotoxicity (P less than 0.005 in all instances) was observed, however, following incubation for 24 h with higher AS concentrations (greater than 100 microgram/ml). Even following incubation with lower concentrations of AS, significant cytotoxicity (P less than 0.006 in all instances) was observed after 48 or 72 h of culture. Scanning electron microscopy (SEM) clearly illustrates the various stages of AS phagocytosis by PAMs. SEM also documented morphological changes in PAMs following AS exposure. These included increased zeiosis and the appearance of a fibrous-like material on the surface of AS fibers following initial contact with the PAM cytoplasmic membrane. Further study of the biological interactions between AS and human cells, such as PAMs, might provide valuable information regarding the etiology of AS-related lung disorders.

Adult↗
PubMed1979

Effects of five experimental treatments of stuttering.

Twenty adult stutterers were exposed to each of five experimental treatments: time-out, noise, delayed auditory feedback (DAF), "wrong" and metronome. In each session a subject spoke for 20 minutes without treatment (baserate) followed by 30 minutes in one of the five experimental conditions. Before the five treatment sessions, subjects accomplished three pre-experimental tasks: expectancy, changeability, and adaptation tasks. Percent stuttering decreased significantly in all conditions, and stuttering duration reduced significantly in all but the noise condition. The amount of reduction in percent stuttering from baserate to treatment (change score) in time-out was positively related to the change scores in DAF and metronome. Change scores in metronome were positively related to change scores in time-out and "wrong." Percent stuttering change scores in noise, DAF, and "wrong" were essentially unrelated. Stuttering duration change scores were related only for the time-out and DAF, and metronome and DAF conditions. In general, the pre-experimental expectancy, changeability, and adaptation scores were unrelated to change scores in any of the experimental conditions. Words spoken per minute did not change significantly from baserate to treatment for any experimental condition except time-out.

Adult↗
PubMed1979

Effects of exercise intensity on food consumption in the male rat.

The effects of two different levels of exercise of equal caloric cost on food consumption and body weight changes was investigated in 24 male rats (initial body weight = 378.3 g, SD = 22.3 g). Open circuit spirometry was used for the collection of respiratory gas exchange during running on the treadmill and these data were used to equate two intensities of exercise to the same caloric expenditure. Food consumption was measured 1 hr, and every 4 hr thereafter for 24 hr during 2 alternate weeks of exercise and rest. Results showed that high intensity exercise (16 m . min-1, 10% mill grade) resulted in depressed food consumption and depressed body weight gain than low intensity exercise (5 m . min-1, zero percentage mill grade) of equal caloric expenditure. Both exercise groups had depressed food consumption and rate of body weight change compared to nonexercise animals.

Animals↗
PubMed1979

The phagocytosis of Candida albicans blastospores and germ tubes by polymorphonuclear leukocytes.

This in vitro study investigates the phagocytosis and killing rate of Candida albicans blastospores and germ tubes by polymorphonuclear leukocytes. Suspensions of C. albicans blastospores and germ tubes were incubated for 60 and 150 min with a neutrophil suspension. The rate of phagocytosis was found to be 92 +/- 3% for blastospores, but only 9.5 +/- 2.5% for germ tubes. The candidacidal activity rate was 29 +/- 6% for blastospores, but only 5.5 +/- 1.5% for germ tubes. Electronmicroscopically, cytoplasmic and plasma membrane alterations of phagocytized yeast cells lying in phagosomes were observed. Short germ tubes surrounded by a phagosomal membrane were found in neutrophils. Older, longer germ tubes were seen in an extracellular position. Usually, several neutrophils were adjacent to these long tubes. Obviously phagocytosis could not take place owing to the size of the germ tubes. The findings indicate that the transition of the yeast phase to the mycelium phase in a case of Candida infection may be a mechanism enabling the parasite to escape phagocytosis by the host.

Candida albicans↗
PubMed1979

Slit-scan flow cytometry of mammalian chromosomes.

A flow cytometer has been constructed which measures total fluorescence and the distribution of fluorescence along isolated, stained mammalian chromosomes. In this device, chromosomes flow lengthwise at 4 m/sec through a 1-micrometer thick laser beam. The fluorescence from each chromosome is recorded at 10 nsec intervals; the sequence of recorded values represents the distribution of fluorescence along the chromosome and is stored in the memory of a waveform recorder. The total fluorescence of each chromosome is also measured and recorded. Preliminary studies show that doublets of 1.83 micrometers diameter microspheres flow with their long axes parallel to the direction of flow and that the two microspheres are resolved in the slit-scan profile. Ethidium bromide stained Muntjac and Chinese hamster chromosomes have also been slit-scanned. Centromeres were resolved in many of the Nos. 1 and 2 Chinese hamster chromosomes and the Nos. 1 and X + 3 Muntjac chromosomes.

Animals↗
PubMed1979

[Use of frozen hypertonic saline in the treatment of pain].

Fifteen cases of patients referred for treatment of acute and chronic pain problems are reported. The results show that both epidural and peripheric hypertonic frozen saline 5 p. 100 injections were effective, as far as three months afterwards. The possible mechanism of action of frozen saline is discussed.

Adult↗
PubMed1979

[The molecular biology of aging -- 15: Structure and function of the genetic apparatus in aging. II. Synthesis and metabolism of RNA].

With aging in different organs there are similar or tissue specific changes of the ribonucleic acids in respect of the quantity, the spectrum of different RNA species and the metabolism of RNA. Among these processes the template function of the chromatin and the behaviour of the RNA polymerases are important influencing factors. In aging the sensitivity of the RNA synthesis against hormonal stimulation is decreased in the most cases. A survey about the results of many in vivo and in vitro experiments of the literature is given. The opinion is advocated that the problems of the gene regulation and gene expression are a important field of work in the experimental gerontology.

Adrenal Cortex Hormones↗
PubMed1979

The feet in diabetes. Roentgenologic observation in 1501 cases.

The manifestations of diabetic osteoarthropathy are described. Computerized analysis of the films of the feet of 1501 diabetic patients showed one or more lesions in 55% of patients. Exostosis (36%), vascular calcifications (25%) and osteoporosis (12.2%) are by far the most frequent symptoms. Geodes (3.7%), destructive lesions (3.9%), sclerosis (4%) and articular lesions (5.1%) are second in frequency. Osteolytic lesions and reconstruction showed a high female predominance, whereas sclerosis is predominant in males (61.6--38.4%).

Diabetes Complications↗
PubMed1979

Muscle and adipose cell development in mice selected for postweaning growth rate.

Genetic selection for postweaning growth rate between 3 and 6 weeks of age resulted in significant changes in body weight, semimembranosus muscle weight, and epididymal fat pad weights. Body weights at 15 weeks of age ranged from 24.9 gm for the Low line (slow growth) mice and 59.4 gm for the High line mice (rapid growth). Total muscle DNA content was decreased in Low line mice and increased in High line mice when compared to Control mice (random bred). RNA to DNA and protein to DNA ratios were not significantly affected by growth rate selection pressure. Selection for high or low growth rate appeared to affect the development of muscle by altering the amount of DNA synthesized, suggesting that growth hormone status was altered by this type of selection. Adipose cell number was reduced in the Low line and increased in the High line when compared to Control mice. Adipose cell size was increased in High line mice when compared to Low and Control lines. The role of adipose cell development in supporting growth selection success is suggested.

Adipose Tissue↗
PubMed1979

[The molecular biology of aging -- 14: Structure and function of the genetic apparatus in aging. I. Changes in the genome].

In the last years there is agreement over the fact that genetic properties have an essential influence on the ageing process. Therefore many scientists choose the genom and its properties as object of the gerontological investigation. This review shows that changes are possible on all of structure levels of the genom down to the lowest molecular stage with increasing age. This concerns as well postmitotic as intermitotic, proliferating cells and tissues, too. Actually repair processes of defective DNA find an increasing consideration. Until now it is not possible to establish if the observed changes are the cause or the result of ageing processes.

Aging↗
PubMed1979

[The human utilization of orally administered 15N-glycine].

In 7 convalescent patients we studied utilisation of a single dose of 15N-labelled glycine. In intervals we estimated total-N, urea-N, NH3-N and their 15N-abundances (urine). The following results were obtained. The peak of ammonium-15N appeared 25 minutes earlier than the peak of urea-15 N. The cumulative elimination of total-15N amounted to 25% of uptake after 24 hours and to 34.4% after 6 days. 12 hours after application 53% of the total amount, excreted within 6 days, were already eliminated. 24 hours after administration 80% of total-15N was urea-15N and 2.8% NH3-15N. Further we found correlations between N-balance (N-application minus excretion) and elimination of 15N-urea: If N-balance got more negative, the amount of cumulative elimination, the portion of urea-15N to total-15N and the percentage of elimination after 12 hours related to 6 days were elevated. That means that in stress condition utilisation of glycine to urea is higher and accelerated. The model seems acceptable, to get information concerning metabolic situation in a simple way.

Administration, Oral↗
PubMed1978

[Nucleotide sequence determination of yeast mitochondrial phenylalanine-tRNA].

The primary structure of mitochondrial tRNAPhe from Saccharomyces cerevisiae, purified by two-dimensional polyacrylamide gel electrophoresis, was determined using, standard procedures on in vivo 32P-labeled tRNA, as well as the new 5'-end postlabeling techniques. We propose a cloverleaf model which allows for tertiary interaction between cytosine in position 46 and guanine in position 15 and maximizes base pairing in the psi C stem, thus excluding the uracile in position 50 from base pairing in the psi C stem. Comparison of the primary structure of this tRNA with all other known procaryotic, chloroplastic or cytoplasmic tRNAsPhe sequences does not lead to any conclusion about the endosymbiotic theory of mitochondria evolution.

Base Sequence↗