Search PubMed⌕ Search

Biomedical subjects

T H Williams

Publications and source records attributed to T H Williams.

At least 37 records · Page 2Linked to original sources
PubMed1989

Comparison of two rapid microscopic methods and culture for detection of Chlamydia trachomatis in ocular and nasopharyngeal specimens from infants.

The data available for the diagnosis of chlamydial infections in infants which compare direct fluorescent-monoclonal-antibody stains (DFAs) with culture are limited to one reagent, MicroTrak (Syva Inc., Palo Alto, Calif.). We therefore performed a comparison of Pathfinder (Kallestad Diagnostics, Chaska, Minn.) and MicroTrak with chlamydia culture. Paired conjunctival and nasopharyngeal specimens for DFAs and cultures were obtained from 56 infants less than 1 month of age with conjunctivitis. The sensitivities for detecting C. trachomatis in conjunctival specimens with MicroTrak and Pathfinder were 93.8 and 88.2%, respectively, and the specificities were 87.5 and 94.9%, respectively. The DFA tests on nasopharyngeal specimens from infants with conjunctivitis did not perform as well. The sensitivities for Pathfinder and MicroTrak were 33 and 50%, respectively. There were a total of six patients with culture-positive chlamydial conjunctivitis whose nasopharyngeal specimens were DFA positive and culture negative; four of the specimens were positive by both DFAs. These six discordant specimens were further evaluated by preparing pellets and smears of the original culture specimens. All six contained typical fluorescing elementary bodies when stained with the Syva DFA reagent.

Chlamydia Infections↗
PubMed1989

The intestine as a model for neuronal plasticity.

This study focuses on establishing the nature and extent of the changes that occur in gastroenteric innervation, specifically the myenteric plexus of the rat ileum, following an injury generated by experimental obstruction. A partial obstruction was accomplished by placing a cuff around the terminal portion of the ileum of the rat. Substantial hypertrophy of the enteric muscle wall occurred after 3-5 weeks. Light microscopic examination of the myenteric plexus revealed changes in the numbers of neuronal perikarya, ganglia and perikarya per ganglia; sizes and shapes of perikarya; and thicknesses of nerve fiber bundles. Using vasoactive intestinal polypeptide (VIP) and substance P light microscopic immunohistochemistry, we observed indications of transmitter accumulation in cell bodies and nerve fibers and reactive, degenerative and regenerative changes in axonal endings. Electron microscopic studies provided evidence for neuroplastic changes, as demonstrated by the appearance of reactive and regenerative, or growth, cones in the myenteric plexus.

Animals↗
PubMed1988

Effects of transcutaneous scopolamine and depth on diver performance.

Transdermal scopolamine is an effective anti-motion-sickness medication that has less CNS side effects at normal ambient pressure than orally ingested agents. To see whether it has an effect on performance at depth, 24 healthy sport divers were exposed to depths equivalent to 5 m (1.5 ATA) and 36 m (4.8 ATA) in a dry recompression chamber, breathing air and wearing a skin patch containing either scopolamine or inactive placebo. Patches and dive depths were presented in a counterbalanced, double-blind experimental design. Tests of sentence comprehension, simple arithmetic, and manual dexterity were used to evaluate psychometric and cognitive performance. Drug side effects were recorded. The Bennett Hand Tool Dexterity Test was evaluated for its suitability for repeated measures testing, and found to be robust. Manual dexterity and sentence comprehension were significantly impaired at depth whereas arithmetic skills were not. No significant effects on diver performance from transdermal scopolamine were seen. Certain side effects such as blurred vision were more common with scopolamine than with placebo. The use of transdermal scopolamine as an antiemetic during diving operations deserves field evaluation.

Administration, Cutaneous↗
PubMed1987

Distribution of vasoactive intestinal polypeptide-immunoreactive structures in the opossum esophagus.

Physiologic evidence that vasoactive intestinal polypeptide (VIP) regulates esophageal smooth muscle in the opossum has been gathered without knowledge of the distribution of VIP in that organ. We examined planar sections stained for VIP by the avidin-biotin complex method, measured VIP content in mucosa and muscularis propria by radioimmunoassay, and compared neural structures reactive to VIP antiserum with those revealed by osmication in the presence of zinc iodide. Immunoreactive terminal nerves interlaced smooth muscle bundles in all layers in all smooth muscle regions, formed loose tangled knots about widely dispersed muscle cells in striated muscle, and supplied vessels and submucosal glands. Bipolar interstitial cells in the circular muscle layer stained by osmication were not VIP-immunoreactive. Perikarya in both submucous and myenteric plexuses were VIP-immunoreactive. Vasoactive intestinal polypeptide-immunoreactive oval cells with round unstained nuclei and a faintly granular cytoplasm were scattered in the muscle in all regions and were concentrated in the planes of the plexuses. Vasoactive intestinal polypeptide content of muscularis propria in the smooth muscle esophageal body exceeded (p less than or equal to 0.05) that in the striated muscle esophageal body and the sphincter region, but contents in the latter two regions did not differ (p greater than or equal to 0.05). Mucosal content exceeded that of muscularis propria. The broad distribution and diversity of immunoreactive structures suggest that VIP may have functions in this organ besides the regulation of smooth muscle.

Animals↗
PubMed1987

Distribution of immunoreactive glia maturation factor-like molecule in organs and tissues.

Using the monoclonal antibody G2-09 raised against bovine glia maturation factor (GMF), we screened various rat organs and tissues for GMF-like immunoreactivity. In the adult animal, with the exception of the heart, GMF was found exclusively in the nervous system, with the cerebellum exhibiting higher specific activity than other brain regions. The nature of the immunoactivity in the heart is presently unclear. None of the body fluids collected from humans, including serum and cerebrospinal fluid, possessed detectable GMF immunoactivity. A phylogenetic comparison revealed the presence of GMF in the brain of al vertebrates studied, from fish to primates. GMF was absent from bacteria and yeast. An ontogenetic study on rats showed the highest GMF level in the fetal brain, with a gradual but steady decrease after birth. However, a substantial amount of GMF persisted even in older animals. GMF was localized in astrocytes and Bergmann glia in the rat brain, using immunostaining at the light microscopic level.

Age Factors↗
PubMed1987

Comparison of enzyme immunoassay and culture for diagnosis of chlamydial conjunctivitis and respiratory infections in infants.

The efficacy of Chlamydiazyme (Abbott Laboratories, North Chicago, Ill.) in detecting neonatal conjunctival and respiratory infections caused by Chlamydia trachomatis was determined by comparison of this enzyme immunoassay (EIA) with the method of isolation of chlamydiae in tissue culture. The sensitivity and specificity of Chlamydiazyme for detecting C. trachomatis in conjunctival specimens from infants with conjunctivitis were 98 and 94%, respectively. For nasopharyngeal infection in infants with conjunctivitis, the sensitivity and specificity were 87 and 92%, respectively. There were nine nasopharyngeal specimens that were Chlamydiazyme positive and culture negative. All of these specimens demonstrated the presence of typical fluorescing chlamydial elementary bodies when pellets of the original specimens were examined with a fluorescein-conjugated monoclonal antibody. When the EIA was performed on nasopharyngeal specimens from infants with suspected chlamydial pneumonia, 6 culture-positive and 10 culture-negative specimens were correctly identified.

Chlamydia Infections↗
PubMed1987

Metabolism of the anti-obesity agent, 4-amino-5-ethyl-3-thiophenecarboxylic acid methyl ester hydrochloride, in rats and dogs.

1. In 24 h, male rats excreted in urine 1% of an intra-gastric 100 mg/kg dose of 4-amino-5-ethyl-3-[4-14C]thiophenecarboxylic acid methyl ester hydrochloride (I) as unchanged I and 59% as 4-amino-5-ethyl-3-thiophenecarboxylic acid (II), mostly conjugated. 2. In rats dosed intra-duodenally with I (50 mg/kg), little I was found in the systemic circulation (less than 2 micrograms/ml) but high concentrations (26 micrograms/ml) were present at five minutes in portal plasma. At five minutes, II was found at 89 and 93 micrograms/ml in systemic and portal plasma, respectively. First-pass ester hydrolysis by the duodenum and liver may explain the near absence of I and the high concentrations of II in systemic plasma. 3. Dogs which received 30 mg/kg 14C-I intra-gastrically, excreted 0.3% I, 30.8% II and 6.8% as 5-ethyl-4-(methylamino)-3-thiophenecarboxylic acid (III), the N-methyl derivative of II. 4. Dogs which received approximately equivalent intra-venous or intra-gastric doses of non-radioactive I and II had high plasma concentrations of II but only small concentrations of I. Plasma concentrations of II after intra-gastric doses of non-radioactive I or II were similar, indicating that both compounds are pharmacokinetically equivalent. I may be a prodrug of II.

Animals↗
PubMed1986

Plasticity of catecholaminergic terminals in rat paraventricular hypothalamic nucleus after 6-hydroxydopamine lesion: an emphasis on bouton sizes and synaptic frequency.

Catecholaminergic (CA) nerve terminals in the paraventricular hypothalamic nucleus (PVN) of adult rats were studied at 4, 21, 56 and 180 days after a single injection of 6-hydroxydopamine (6-OHDA) neurotoxin into the right lateral ventricle of the brain. We previously described and quantified the extent of CA terminal sprouting in the PVN after 6-OHDA lesions. For this communication we studied parameters, specifically the bouton sizes and the synaptic frequencies of CA terminals during the renewal process, and evaluated how changes of these parameters are related to axonal sprouting. The CA boutons were identifiable in the electron microscope by exhibiting small granular vesicles (SGVs) after central administration of 5-hydroxydopamine (5-OHDA) marker. The marked CA boutons were measured and further categorized according to whether or not they were associated with distinct synaptic specializations at various post-lesion stages. The average sizes of CA boutons were strikingly similar in their diameters (1.0 micron) for both control and experimental tissues. However, CA boutons larger than 2.1 micron were rare and seen more often in the experimental tissues with 6-OHDA lesion and were sustained up to 180 days after lesions. Catecholaminergic profiles with ultrastructural features of growth cones were also seen in the PVN following the 6-OHDA lesions, indicating that there is growth activity in the PVN after 6-OHDA lesion. There were 33% of CA boutons in the PVN from the control tissues that appeared to have synaptic contacts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic Fibers↗
PubMed1986

Microbial products. VIII. Azinothricin, a novel hexadepsipeptide antibiotic.

Azinothricin was isolated from the culture filtrate of Streptomyces sp. X-14950 in crystalline form. It represents a new type of hexadepsipeptide antibiotic as it contains a 19-membered cyclodepsipeptide ring composed of six unusual amino acids and bearing a novel C21 side chain. Azinothricin was identified as [(3S,4S,7R(S*),10S,17R,20S,23R)[2S(2'R*,5'S*, 6'S*)3S*]]-alpha-ethyl-6-(3-ethyl-1, 5-dimethyl-4-oxo-1,5-heptadienyl)- N-(1,8, 14,15,18,21,27-heptaaza-21-hydroxy-7-(1-hydroxyethyl)-2,6,9,16,19, 22-hexaoxo-4-isopropyl-20-(methoxy-methyl)-17,18-dimethyl-5-oxa tricyclo [21.4.0.0(10,15)]heptacosan-3-yl)tetrahydro-alpha, 2-dihydroxy-5-methyl-2H-pyran-2-acetamide and is primarily active against Gram-positive microorganisms.

Anti-Bacterial Agents↗
PubMed1985

Topographical distribution of pro-opiomelanocortin-derived peptides (ACTH/beta-END/alpha-MSH) in the rat median eminence.

The detailed distribution of adrenocorticotropin (ACTH), beta-endorphin (beta-END) and alpha-melanotropin (alpha-MSH) immunoreactivity was examined in the rat median eminence (ME) and pituitary stalk using light microscopic immunocytochemistry and radioimmunoassay (RIA). Nerve fibers and varicosities immunoreactive for ACTH/beta-END/alpha-MSH had identical distributions in the ME suggesting that they are part of the same arcuate proopiomelanocortin neuronal (POMC) system. The quantitative image analysis of POMC immunoreactive varicosities in the ME indicates no significant differences between the various rostro-caudal segments. In the main (preinfundibular) portion of the ME, a moderate density of immunoreactive elements was located in the lateral part of the internal zone and throughout the postinfundibular ME. Very few scattered varicosities were observed in the neurohemal (external) zone and in the pituitary stalk. By RIA, alpha-MSH is present in a substantially higher concentration than ACTH and beta-END throughout the ME. Knife cuts between the arcuate nucleus and ME indicate that proopiomelanocortin (POMC) fibers enter the ME in its whole rostro-caudal extent. Thus POMC neurons seem to provide innervation of structures in the internal zone but not in the neurohemal/external/zone where the portal capillary system is located. Moreover, the observation that the density of immunoreactive elements is substantially lower in the pituitary stalk than in the ME, suggests that the majority of immunoreactive fibers in the internal zone are not fibers of passage directed towards the neurohypophysis.

Adrenocorticotropic Hormone↗
PubMed1985

Effects of intracerebroventricular 6-hydroxydopamine on catecholaminergic fibers in the rat hypothalamus.

Regeneration in the central nervous system has been claimed to be very limited and abortive, although functional regeneration of some of its pathways after destruction has been observed. The exact mechanisms by which axons regenerate fully or fail to have functional regeneration remain to be studied further. We explored whether or not there is a regional difference in regeneration of central catecholaminergic (CA) neurons in the hypothalamus of young adult rats after 6-hydroxydopamine (6-OH-DA) treatment. Four days after treatment, the numbers of CA terminals and axons were significantly reduced in the paraventricular hypothalamic nucleus, periventricular hypothalamic nucleus, supraoptic commissure (SOC), and dorsomedial hypothalamic nucleus as assessed by a morphometric quantitation on fluorescence microscopy micrographs; CA axons were gradually increased in numbers after the treatment. The number of CA varicosities in the supraoptic commissure was restored to 96% of control 180 days after the 6-OH-DA lesion, whereas the actual numbers of CA varicosities in the paraventricular, periventricular, and dorsomedial hypothalamic nuclei were attained at 79, 79, and 68% of control values, respectively. Our results indicate that CA fibers in the supraoptic commissure possess more regenerative potential than the three other hypothalamic regions studied, suggesting a regional difference in CA nerve sprouting during neuroplasticity within the hypothalamus. The favorable regeneration of CA axons in the supraoptic commissure implies to us that some trophic features along that pathway, particularly near the third ventricle, may have been stimulated after chemical lesion using 6-OH-DA, and gradually released in the distal field of the supraoptic commissure to attract CA stumps to sprout. These factors may thus induce both regenerative sprouting and collateral sprouting resulting in vigorous regrowth of CA fibers in the supraoptic commissure.

Animals↗
PubMed1985

The incidence and severity of post-asphyxial encephalopathy in full-term infants.

The incidence of clinically significant birth asphyxia was assessed over a 4-year period in a busy teaching hospital maternity hospital. The overall incidence was 6.0 per 1000 live-born deliveries of whom 2.1 per 1000 showed severely abnormal features including seizures or coma. There was a marked seasonal distribution (more common in winter than summer months) and intrauterine growth retardation occurred in 25% of asphyxiated infants. Only 1.6% of these infants were large for gestation age. There is some evidence that the incidence of this condition has not changed over a 10-year period.

Apgar Score↗
PubMed1985

Fire at will.

Explore the source record for details and available documents.

Employment↗
PubMed1984

Distribution and projections of cholecystokinin-immunoreactive neurons in the hypothalamic paraventricular nucleus of rat.

Analysis of coronal sections from colchicine-treated rat brains reveals that CCK-immunoreactivity (CCK-ir) is present in two distinguishable neuronal systems in the paraventricular nucleus (PVN). More than 60% of these cells were found to be typical parvicellular neurons; the remainder were magnocellular neurons. The magnocellular CCK-ir neurons were concentrated in the medial magnocellular subdivision, while more caudally they formed a ring around a zone of unstained magnocellular neurons. Immunostained parvicellular neurons predominate in medial and periventricular parvicellular subdivisions. The efferent projections of CCK-ir neurons were investigated by looking for retrograde accumulation of CCK-ir in cell bodies after selective knife cuts. A parasagittal cut of the lateral retrochiasmatic area as well as transection of the rostral median eminence resulted in an accumulation of CCK-ir material in a large number of both parvi- and magnocellular neurons. After pituitary stalk lesions, however, increased staining was only seen in magnocellular neurons. It is inferred that the magnocellular (presumed oxytocin-CCK) cells send their axons to the pituitary, whereas axons of CCK-ir parvicellular neurons appear to terminate in the median eminence. After transection of the medial forebrain bundle (MFB), immunostaining increased in a small number of scattered transected fibers proximal to the knife cut and in a few perikarya in the PVN, indicating that very few CCK cells may send descending fibers to the lower brainstem.

Animals↗