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Biomedical subjects

F Martin

Publications and source records attributed to F Martin.

At least 487 records · Page 27Linked to original sources
PubMed1983

Liposome induction or enhancement of macrophage-mediated cancer cell lysis.

Liposomes of different composition have been used to modify macrophage-mediated destruction of syngeneic cancer cells through a modulation of membrane lipid content of macrophages and/or tumor cells. Dipalmitoylphosphatidylcholine (DPPC)1 liposomes induce cancer cell lysis by normal, non-tumoricidal, peritoneal macrophages and enhance tumor cell destruction by BCG-activated macrophages. This effect was produced by large and small unilamellar liposomes, which are in the 25,000 g supernatant of sonicated preparations. Addition of cholesterol or negative charges carried by dicetylphosphate supressed the effect of DPPC liposomes on macrophage-mediated cytolysis. Enhancement of macrophage-mediated tumor cell lysis was observed when both cancer cells and macrophages were incubated with DPPC liposomes, but not when macrophages and/or tumor cells were preincubated with liposomes prior to their coincubation. Liposomes did not promote the binding of the cancer cells to the macrophages. Liposomes could promote formation of phospholipid domains within the plasma membrane of both tumor cells and macrophages leading to the destruction of cancer cells through a temporary fusion with the macrophages.

Animals↗
PubMed1983

Effect of Methionine Sulfoximine on the Accumulation of Ammonia in C(3) and C(4) Leaves : The Relationship between NH(3) Accumulation and Photorespiratory Activity.

Additions of methionine sulfoximine (MSX), an inhibitor of glutamine synthetase (GS), result in an increase in NH(3) in seedling leaves of C(3) (wheat [Triticum aestivum cv. Kolibri] and barley [Hordeum vulgare var Perth]) and C(4) (corn [Zea mays W6A x W182E] and sorghum [Sorghum Vulgare var MK300]) plants. NH(3) accumulation is higher in C(3) (about 17.8 micromoles per gram fresh weight per hour) than in C(4) (about 4.7 micromoles) leaves. Under ideal conditions, when photosynthesis is not yet inhibited by the accumulation of NH(3), the rate of NH(3) accumulation is about 16% of the apparent rate of photosynthesis. A maximum accumulation of NH(3) was elicited by 2.5 millimolar MSX and was essentially independent of the addition of NO(3) (-) during either the growth or experimental period. When O(2) levels in the air were reduced to 2%, MSX resulted in some accumulation of NH(3) (6.0 micromoles per gram fresh weight per hour). At these levels of NH(3), there was no significant inhibition of rates of CO(2) fixation. There was also a minor, but significant, accumulation of NH(3) in corn roots treated with MSX. Inhibitors of photorespiration (isonicotinic hydrazide, 70 millimolar; 2-pyridylhydroxymethanesulfonic acid, 20 millimolar) or transaminase reactions (aminooxyacetate, 1 millimolar) inhibited the accumulation of NH(3) in both C(3) and C(4) leaves. These results support the hypothesis that GS is important in the assimilation of NH(3) in leaves and that the glycine-serine conversion is a major source of that NH(3).

Journal Article↗
PubMed1983

Enzyme-Linked Immunosorbent Assay of Fungal NADP-Glutamate Dehydrogenase.

A sensitive and reliable method has been developed for the quantitation of NADP(+)-glutamate dehydrogenase from the phytopathogenic Ascomycete Sphaerostilbe repens using a two-step competitive enzyme-linked immunosorbent assay. Purified enzyme was adsorbed noncovalently to polystyrene wells and rabbit immunserum was allowed to bind to antigensensitized wells. Bound specific antibody was visualized by goat antirabbit immunoglobulin covalently linked to alkaline phosphatase using paranitrophenylphosphate as the substrate. Increasing amounts of purified enzyme or crude fungal extracts were quantitated by their ability to inhibit specific antibody adsorption to antigen-coated polystyrene wells. This system proves to be useful in the range of 10 to 80 nanograms of enzyme level. Using this assay, identical amounts of NADP(+)-glutamate dehydrogenase were found in mycelia grown on nitrate and ammonia sources.

Journal Article↗
PubMed1983

Chronic alcohol excess is associated with selective but reversible injury to type 2B muscle fibres.

Patients drinking more than 100 g alcohol/day for longer than three years develop atrophy of striated muscle fibres. This predominantly affects type 2B fibres which are dependent on anaerobic glycolytic metabolism. Atrophy of type 1 and type 2A fibres, which in addition use aerobic mitochondrial respiration, only occurs in the most severe cases and then only to a lesser degree. Abstention from alcohol reverses the changes in muscle which slowly return to normal. Selective injury to type 2B fibres indicates that search should be made for an alcohol-induced biochemical lesion affecting the anaerobic glycolytic pathways of the muscle fibre.

Adult↗
PubMed1983

Chronic alcoholic skeletal muscle myopathy: a clinical, histological and biochemical assessment of muscle lipid.

Muscle biopsy samples were analysed from five control subjects, four patients with mild to moderate fibre atrophy and four patients with severe atrophy. Patchy increase in lipid was noted with oil red O staining but there was no consistent association of lipid with selective fibre types. Ultrastructural studies demonstrated lipid droplets both subjacent to the sarcolemma and between fibrils. Quantitative analysis showed that the increased lipid was solely due to excess triglyceride. GLC analysis of free and esterified acids was performed. The profiles were essentially similar for the phospholipid and free fatty acid fractions. The triglyceride fraction showed a decrease of myristate, stearate and linoleate with an increase in oleate and arachidate in the alcoholic tissue compared with control. The cholesteryl ester fraction showed an increase in palmitate with a decrease in stearate and oleate in the alcoholic muscle. The accumulation of lipid correlated with mean daily alcohol consumption but not with degree of atrophy suggesting that the two processes probably had different pathogenic mechanisms.

Adult↗
PubMed1983

Effects of epinephrine on resting potential in normal and hypertrophied cardiac muscles.

The role of the Na-K pump in the control of cellular ion balance has long been appreciated. Recent studies suggest that the manner in which this ion transport system functions in hypertrophied failing (HF) cardiac muscle is markedly different from that seen in normal muscles. The ability of the sympathetic neurohormone, epinephrine, to modulate membrane potential changes thought to reflect the activity of the Na-K pump in normal and HF cardiac muscle was examined in this study. Specifically rate-related changes in membrane potential (Emax) thought to be associated with the Na-K pump were measured in intact functioning cat papillary muscles. The results of these studies demonstrate that the rate-related changes in Emax thought to be associated with Na-K activity were markedly altered in HF cardiac muscles. Emax in these muscles responded to periods of transient stimulation by first depolarizing and then slowly returning to a new steady state which was depolarized with respect to the initial predrive Emax. Emax in normal muscles also depolarized on drive, but returned to a new steady state more rapidly and eventually hyperpolarized. Epinephrine significantly affected these rate-related changes in Emax in normal muscles by causing all the rates of change in Emax to be increased. In HF muscles, on the other hand, epinephrine had no significant effect on these parameters at the concentration tested. These results suggest that under certain conditions HF cardiac muscle may be incapable of maintaining normal resting membrane potentials. In addition the modulating influence of epinephrine is markedly blunted.

Action Potentials↗
PubMed1983

Short-term treatment with sucralfate or cimetidine in gastric ulcer: preliminary results of a controlled randomized trial.

The aim of this study was to compare the healing capacities of sucralfate and cimetidine in gastric ulcer. Twenty-nine patients were randomly assigned to active sucralfate (1 g qid) and cimetidine placebo, or to cimetidine (300 mg qid) and sucralfate placebo. The patients were endoscoped before entry into the study, after 4 wk, and after 8 wk if complete healing was not found at 4 wk. Twenty-five patients completed the study. After 4 wk, 50% (6/12) of the sucralfate patients had healed in comparison to 54% (7/13) of cimetidine patients. After 8 wk, the cumulative healing rates were 75% and 77%, respectively. The results indicate that sucralfate is as effective as cimetidine in the short-term treatment of gastric ulcer.

Adult↗
PubMed1983

[The activity of the supraglottal sphincter during phonation].

By means of the measurement of the aperture of the upper laryngeal sphincter it is shown that the sphincter constriction increases when the pitch is lowered and/or the voice intensity is raised. The sphincter movement does not result from the action of extrinsic laryngeal muscles. Moreover, the action of the adductor muscles results in a constriction of the supraglottal sphincter. Out of this group of muscles the lateral thyroarytenoid muscle is dominant. Since it is the strongest muscle of the group of adductors, it also activates the glottal and the supraglottal sphincters, and only this muscle guarantees glottal closure at a relaxed vocalis muscle (low pitch) and/or high subglottal pressure (high intensity). EMG data acquired from the lateral thyroarytenoid muscle at phonation at various pitch levels and different voice intensities confirm the assumed muscular function. The EMG activity increases with descending pitch level and/or with increasing voice intensity.

Electromyography↗
PubMed1983

[Bilateral congenital lower lip fistulas].

Congenital lower labial fistulas are extremely rare. This deformity of the vermilion border of the lower lip constantly appears symmetrically to the midline in a frontal direction with blind ending ducts and oval openings. The different pathogenetic causes are reviewed in accordance with the different gradual malformations described in the literature. In contrast to the upper cleft lip and/or cleft palate, congenital bilateral fistulas of the lower lip form a new, distinct syndrome explained by an arrested development leading to cross sulci resulting from a pathological cleaving process. In most cases a striking inheritance pattern with an autosomal dominant trait is associated with this disease. A family suffering from bilateral congenital lower lip fistulas and their leukocyte antigens are presented. All members of this family affected with this anomaly expressed an A3 Bw60 antigen suggesting a close correlation with the HLA-system of the major histocompatibility complex on the leukocytes.

Child↗
PubMed1983

[Electrodiagnostic and histochemical studies on the effect of electric stimulation on the atrophy of denervated laryngeal muscles in animal experiments].

UNLABELLED: Electrodiagnostic and histometric investigations have been carried out on 56 adult male rabbits following unilateral paralysis of the recurrent laryngeal nerve. Exponential current impulses were externally applied. The excitation threshold was determined endoscopically and also described graphically in terms of the excitation intensity as a function of time (I/t-curves). The diagnostic results thus obtained permit determination of the corresponding excitation parameters for therapy. The success of the therapy was evaluated from histometric data on type I and type II fibres of the vocalis and the posterior cricoarytenoid muscles. RESULTS: 1. The stimulation of denervated laryngeal muscles by external application of exponential current impulses is selective. 2. The extent of the neurogenous atrophy of denervated muscles following paralysis of the recurrent nerve can be diagnosed electrically. 3. This atrophy could be significantly reduced by proper choice of stimulation parameters within the time span of the experiment (28 days).

Animals↗
PubMed1983

[Bilemia. Considerations apropos of a case].

The Authors report a case of bilemia, a complication of hepatic biopsy. They analyse the physiopathogenetic problems and those of surgical tactics, and emphasize the importance of retrograde and/or interoperative cholangiography ii the diagnostics of such disease.

Adult↗
PubMed1983

[The role of the cricopharyngeal muscle in phonation].

Intraluminal esophageal manometry has been employed to study cricopharyngeal muscular function at different pitch levels. The activity of the cricopharyngeal muscle (CP) increases continually with rising pitch but is not influenced by the vocal sound pressure level. In the lower part of the chest register, the muscular pressure is lower than the pharyngo-esophageal pressure at rest. At high pitch levels, the pressure is higher than during swallowing. The CP has a dual function: With increasing pitch, the CP cooperates synergistically with the cricothyroid muscle (CT), indicated by increasing muscular pressure in the upper esophageal sphincter. On the other hand, the CP shortens the vocal cords by rotating the cricoid cartilage in anterior direction, thus acting antagonistically to the CT.

Cricoid Cartilage↗