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Biomedical subjects

G T Carter

Publications and source records attributed to G T Carter.

At least 37 records · Page 2Linked to original sources
PubMed1998

Cell wall active antifungal compounds produced by the marine fungus Hypoxylon oceanicum LL-15G256. II. Isolation and structure determination.

Fermentations of the marine fungus Hypoxylon oceanicum (LL-15G256) were found to have potent antifungal activity. Isolation and purification of the antifungal agents provided two classes of compounds, macrocyclic polylactones and the lipodepsipeptides 15G256 gamma (1), 15G256 delta (2) and 15G256 epsilon (3). The isolation and structure elucidation of the lipodepsipeptides, all containing D-glutamate, L-serine, and the rare amino acid beta-ketotryptohan, are described in this paper.

Antifungal Agents↗
PubMed1998

Hongoquercins A and B, new sesquiterpenoid antibiotics: isolation, structure elucidation, and antibacterial activity.

Two new sesquiterpenoid antibiotics, hongoquercins A and B, were isolated from the extracts of an unidentified fungus. The structures of both metabolites were determined by spectroscopic analysis. They are related to a class of compounds commonly found in brown algae and dictyoceratid sponges. Hongoquercin A exhibited moderate activity against gram-positive bacteria.

Anti-Bacterial Agents↗
PubMed1998

The role of physiatry in the management of neuromuscular disease.

Patients with neuromuscular disease (NMD) are complex and pose a myriad of clinical problems. Management is best carried out by a team consisting of physicians, physical, occupational, and speech therapists, social workers, vocational counselors, and psychologists, among others. Physiatrists are well-suited to this type of multi-disciplinary care and can play a significant role in the care of these patients.

Activities of Daily Living↗
PubMed1998

Comprehensive management of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive motor neuron disease that poses a myriad of clinical problems. Patients with ALS are best treated in a multidisciplinary setting involving physicians, clinical nursing specialists, and physical, occupational, speech, and respiratory therapists, as well as psychologists and social workers. Palliative and rehabilitative strategies may ease suffering, while new treatments provide hope for effective treatment of this disease.

Algorithms↗
PubMed1997

Electromyographic and lower extremity short time to inversion recovery magnetic resonance imaging findings in lumbar radiculopathy.

To determine if short TI (time to inversion) recovery (STIR) magnetic resonance imaging (MRI) is useful in assessing lower extremity (LE) denervation in subacute lumbar radiculopathy (LR), 25 subjects underwent lumbar spine MRI, LE STIR MRI and needle electromyography (EMG). In 23 (92%) subjects there was a positive correlation between LE STIR MRI and EMG (P < 0.009). Increased signal intensity on LE STIR MRI corresponds closely with spontaneous activity on EMG in subacute LR and may be a useful adjunct diagnostic tool.

Electromyography↗
PubMed1996

Focal posterior interosseous neuropathy in the presence of hereditary motor and sensory neuropathy, type I.

A 30-year-old male with hereditary motor and sensory neuropathy, type I (HMSN I), presented with asymmetric weakness of finger extension and radial deviation with left wrist extension, previously felt to be a manifestation of the peripheral neuropathy. Nerve conduction studies confirmed HMSN I; however, needle EMG revealed marked, ongoing axonal loss in muscles innervated by the left posterior interosseous nerve (PIN) only. At surgery there was focal fusiform swelling in the PIN at exit from the supinator muscle, compatible with localized hypertrophic neuropathy, which has not been reported before in HMSN I. A concomitant focal mononeuropathy should be considered in cases of hereditary neuropathy with marked asymmetry of weakness.

Adult↗
PubMed1995

Isolated femoral mononeuropathy to the vastus lateralis: EMG and MRI findings.

A 16-year-old female track athlete experienced sudden onset of right anterolateral thigh pain, initially thought to be cramping. After 2 months of continued postexercise pain she sought medical evaluation. A 3-cm thigh circumference discrepancy was noted on physical exam. She was referred for electromyography (EMG) and magnetic resonance imaging (MRI) studies. Femoral and screening nerve conduction studies were normal. Needle EMG revealed acute neuropathic changes confined to the right vastus lateralis only. These findings were confirmed by MRI, including short T1 inversion recovery (STIR) sequences. All other medical work-up was normal, including lumbar and pelvic MRI, and complete serologic studies. This case represents a unique presentation of an idiopathic femoral mononeuropathy isolated to the vastus lateralis only, which has not been previously reported. The highly unusual anatomical presentation of this case illustrates the emerging complementary usefulness of EMG and MRI in delineating neuromuscular pathology.

Action Potentials↗
PubMed1995

Effect of voluntary wheel-running exercise on muscles of the mdx mouse.

The purpose of this study is to determine whether dystrophin-deficient mdx mice are more susceptible to muscle injury and functional impairment than normal C57 mice when allowed to exercise voluntarily on mouse wheels. The mdx mice were significantly impaired when compared to controls as shown by functional, contractile and morphometric responses. The distance young mdx mice ran was 67-78% of young C57 mice, while adult mdx mice ran 31-48% of adult controls. After exercise the slow, oxidative soleus of young and adult mdx mice exhibited hypertrophy with no changes in strength or fatiguability, while the young C57 mice increased strength and the adults became less fatiguable. In the adult mdx mice the fast EDL, which is primarily glycolytic, exhibits slight hypertrophy with a loss of strength, while the young exhibit no changes. These results indicate that the mdx mouse adapts differently than the C57 mouse to even moderate exercise.

Adaptation, Physiological↗
PubMed1995

Base-catalyzed isomerism in elfamycin antibiotics. Structures of ganefromycins epsilon and epsilon 1.

The structures of ganefromycins epsilon (2a) and epsilon 1 (2b) have been determined by spectroscopic techniques. The compounds are isomeric deoxygenated precursors of the parent antibiotics ganefromycins alpha and beta. The nature of the isomerism was determined by chemical interconversion experiments and spectroscope analysis to be a change in configuration at C-21. Evidence is provided for other cases of this type of isomerism in the elfamycin class of antibiotics.

Anti-Bacterial Agents↗
PubMed1995

Isolation, characterization and structure of a new allenic polyine antibiotic produced by fungus LL-07F275.

Antibiotic 07F275 (1), produced by submerged fermentations of fungal culture LL-07F275, was isolated and characterized despite its inherent instability. Its UV spectrum was identical with that of nemotin, a member of the allenic polyacetylene family, but a molecular weight of 218 daltons indicated a new compound. Structure 1 was determined on the basis of spectroscopic evidence, particularly NMR. Since 1 is a thirteen carbon-containing allenic diyne, it is closely related to mycomycin.

Alkynes↗
PubMed1994

The identification of a gene family in the Saccharomyces cerevisiae ergosterol biosynthesis pathway.

The Saccharomyces cerevisiae ERG24 gene, encoding sterol delta 14 reductase (Erg24p), was cloned by selecting strains carrying sequences on a 2 mu-based vector for resistance to the morpholine fungicide, fenpropimorph (Fp). Four distinct plasmid inserts which conferred Fp resistance (FpR) were recovered (plasmids pML99, pML100, pML101 and pM103). Although Fp is reported to inhibit activity of Erg24p and sterol delta 8-delta 7 isomerase (Erg2p; encoded by ERG2), none of the inserts had restriction maps resembling ERG2. In addition, a 2 mu plasmid overexpression of the ERG2 sequence did not produce FpR. Characterization studies were focused on plasmid pML100, because it was the only plasmid to confer FpR consistently when tested in a number of different genetic backgrounds. Tests with a panel of fungicides indicated that pML100 conferred significant resistance only to compounds (Fp, tridemorph, fenpropidin and azasterol) which have a shared site of action, Erg24p. An insertional disruption of pML100 resulted in an obligate anaerobic phenotype, indicating a lesion in sterol biosynthesis. Sterol analysis of the disrupted mutant demonstrated the accumulation of ignosterol, indicating a loss of Erg24p activity. A SphI-XbaI fragment of pML100 was sequenced, revealing the presence of an ORF encoding a 438-amino-acid protein, which is highly similar to those encoded by two previously reported yeast drug sensitivity genes, sts1+ (Schizosaccharomyces pombe) and YGL022 (S. cerevisiae). Analyses of these genes demonstrated that strains carrying disruptions of sts1+ or YGL022 have ergosterol biosynthesis defects in the enzyme, sterol C-24(28) reductase (Erg4p; encoded by ERG4).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Martinomycin, a new polyether antibiotic produced by Streptomyces salvialis. I. Taxonomy, fermentation and biological activity.

Actinomycete culture LL-D37187 has been found to produce the new polyether antibiotic martinomycin. Taxonomic studies, including morphological, physiological, and cell wall chemistry analyses, revealed that culture LL-D37187 is a novel streptomycete species, and the proposed name is Streptomyces salvialis. Martinomycin exhibits activity against the Southern Army Worm (Spodoptera eridania) and Gram-positive bacteria.

Animals↗
PubMed1994

The use of fluorescent dextrans as a marker of sarcolemmal injury.

We investigated the use of intravenously injected fluorescent dextran molecules (FDx) as a histological marker of sarcolemmal injury. Using fluorescent microscopy, uptake of FDx (average MW 10 kD) was assessed in sections of quadriceps muscles from three models: 1) normal (C57BL/10SnJ) mice, 2) normal mice run downhill (0, 3, and 7 days post exercise), and 3) non-exercised mdx (dystrophin-deficient) mice. These were compared to serial sections stained with hematoxylin and eosin (H&E). In control muscles, strong fluorescence was seen between fibers (intercellular). Intracellular FDx was observed within cells of the quadriceps from normal mice run downhill at days 0 and 3 post exercise, but not at day 7. On H&E staining, muscle pathology was not observed until day 3, with regeneration by day 7. Intracellular FDx was also observed within mdx muscles, particularly in fibers that appeared pre-necrotic on H&E stained sections. FDx appears to be useful as a histological marker of changes in sarcolemmal integrity associated with muscle injury from eccentric exercise or muscle disease.

Animals↗
PubMed1994

Effects of exhaustive concentric and eccentric exercise on murine skeletal muscle.

C57BL/10SnJ mice were run to exhaustion on a treadmill at a 20 degrees incline, uphill or downhill. Contractility, morphology, and histology were evaluated in the soleus and extensor digitorum longus (EDL) muscles at days 0, 3, and 7 postexercise. Serum creatine kinase was elevated immediately postexercise (681% increase downhill and 225% increase uphill). After uphill running, the soleus had a significant increase in cross-sectional area (CSA) and decreased tetanic tension/CSA and twitch contraction time through day 7. The EDL showed increased CSA, decreased tetanic and twitch tension, and increased fatigue at day 0 only, with no other contractile abnormalities. After downhill running, the EDL showed reduced tetanic and twitch tension, but no fatigue or morphometric differences, whereas the soleus showed no significant abnormalities. No significant muscle histopathology was observed at any time following uphill or downhill running. This study indicates that both exhaustive eccentric and concentric exercise may produce significant impairments in muscle contractility without inducing histopathology. Exhaustive concentric exercise also induces muscle swelling and may preferentially impair slow twitch fibers.

Animals↗