Search PubMed⌕ Search

Biomedical subjects

C L Smith

Publications and source records attributed to C L Smith.

At least 307 records · Page 17Linked to original sources
PubMed1986

Sensory neurons supplying touch domes near the body midlines project bilaterally in the thoracic spinal cord of rats.

Sensory neurons that project bilaterally to laminae III-V of the dorsal horns in the thoracic spinal cord of rats were described in a previous anatomical study. The electrophysiological experiments reported here show that these neurons innervate skin near the dorsal and ventral midlines. Three series of experiments were undertaken: the regions of skin supplied by subdivisions of thoracic nerves were mapped by recording from the subdivisions while mechanically stimulating the skin; subdivisions containing the axons of contralaterally projecting sensory neurons were identified by antidromic activation from the contralateral dorsal horn; the receptive fields of individual sensory neurons and dorsal horn neurons were characterized by single-unit recording methods. Contralaterally projecting sensory neurons had axons in subdivisions of the thoracic nerves that supply skin adjacent to the body midlines. Their receptive fields were located near the dorsal or ventral midline but did not extend onto the contralateral side of the body. Most of the neurons were slowly adapting "type I" units supplying touch domes. Dorsal horn neurons receiving input from contralateral sensory neurons had receptive fields that overlapped the dorsal or ventral midline. This bilateral representation of skin near the midlines may be important for the fusion of the sensory maps of the right and left sides of the body.

Action Potentials↗
PubMed1986

Relationship between disease activity indices and colonoscopic findings in patients with colonic inflammatory bowel disease.

The Crohn's disease activity index, a similar index devised for patients with ulcerative colitis, and other commonly used laboratory indicators of disease activity have been studied in 50 patients with colonic inflammatory bowel disease undergoing routine colonoscopic assessment and compared with the histological extent and activity of disease. There was only poor correlation between the colonoscopic or histological findings and the indices of disease activity studied, showing that these are not reliable measures of disease activity or extent at the tissue level.

Blood Sedimentation↗
PubMed1986

Serum calcium fractions in essential hypertensive and matched normotensive subjects.

Concentrations of serum total calcium and serum calcium fractions were compared between 28 hypertensive subjects and 28 race-sex-age-matched normotensive controls. Mean levels of serum total calcium were not different between the two groups. Hypertensive subjects had lower mean serum levels of ultrafilterable calcium (-0.32 mg/dl; p = 0.01), ionized calcium (-0.07 mg/dl; p = 0.09), and complexed calcium (-0.23 mg/dl; p = 0.04) and higher levels of protein-bound calcium (+0.36 mg/dl; p = 0.07). Estimated dietary calcium intake was similar in the two groups. These findings add to the evidence that essential hypertension is associated with perturbations in calcium metabolism.

Adult↗
PubMed1986

Drug residues in milk after intrauterine injection of oxytetracycline, lincomycin-spectinomycin, and povidone-iodine in cows with metritis.

A study was conducted to document the maximum retention times of antimicrobial residues in milk after their use in intrauterine treatment of metritis in lactating cows and to evaluate several risk factors hypothesized to influence the retention time of these drugs. Oxytetracycline (3 g), lincomycin-spectinomycin (2 g of one-third lincomycin and two-thirds spectinomycin), or povidone-iodine (6 g) were given to cows with metritis by intrauterine route. The Bacillus stearothermophilus var calidolactis disk assay was performed on each milk sample. Of the 61 cows treated with oxytetracycline, 30 had residues in their postinjection milk for variable periods (range, 12.5 to 44.0 hours; mean, 26.6 +/- 10.3). Of the 47 cows treated with lincomycin-spectinomycin, 17 had residues in their postinjection milk for various periods (range, 14.5 to 24 hours; mean, 19.5 +/- 8.9). Povidone-iodine was not detected in milk. Because a high number of cows (n = 61) were treated with oxytetracycline, only data from these cows were used in testing the influence of 3 factors (severity of metritis, time after parturition when cows with metritis were treated, and parity) on maximum retention of the drug in milk. Severity of metritis did not have a significant influence (P greater than or equal to 0.1) on the maximum retention time of the drug. The retention time decreased linearly with the increase of time after parturition when the cow with metritis was treated. First lactation cows had a significantly (P less than or equal to 0.01) shorter retention time than did older cows.

Animals↗
PubMed1985

Response of recA-dependent operons to different DNA damage signals.

The responses of three recA-dependent operons (recA, lambda, and phi 80), with three different repressors, to five DNA damage treatments were compared. Each operon shows a unique induction onset time constant over a wide dose range. However, the extent of response is variable within the same dose range. Individual Escherichia coli cells show a graded SOS response to different levels of DNA damage. Apparently phage repressors have evolved to discriminate between lethal and sublethal DNA damage to a host by a wide variety of agents. Multiple induction signals could account for the complex behavior of this system. For example, the absence of the recBC enzyme from a cell leads to complex changes in SOS induction onset times and extents.

Coliphages↗
PubMed1985

Antigenic variants of CVS rabies virus with altered glycosylation sites.

The virion-associated glycoprotein of the CVS-11 strain of rabies virus exists in two forms, GI and GII, which differ in their carbohydrate content. The structural relationship between GI and GII is investigated in order to account for the difference in glycosylation. Partial sequence analysis and mapping of tryptic glycopeptides isolated from the parent CVS-11 GI and GII glycoprotein forms revealed that two of the three predicted glycosylation sites (at Asn-204 and Asn-319) were utilized in the GI form whereas only one of these two sites (at Asn-319) was utilized in the GII form. One predicted glycosylation site (at Asn-37) was not utilized in either species. In the variant virus, RV231-22, a single glycoprotein species was detected which corresponded in electrophoretic mobility to the GI form of the parent virus. Nucleotide sequence analysis of the variant glycoprotein gene revealed a base mutation which specifies an amino acid change six residues upstream from the predicted glycosylation site at Asn-204. This single amino acid substitution apparently results in utilization of the signal at Asn-204 in the GII form of RV231-22 virus. The amino acid substitution is discussed in relation to altered conformation. In the variant virus RV194-2 (F3), both GI and GII glycoprotein forms were present, but each revealed slower electrophoretic mobilities compared with the corresponding parent glycoprotein forms in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). An extra glycosylation site was identified in both glycoprotein forms of this variant virus.

Amino Acid Sequence↗
PubMed1985

Potential of SeHCAT retention as an indicator of terminal ileal involvement in inflammatory bowel disease.

The absorption of 75Se-23-selena-25-homotaurocholate (SeHCAT) was compared with vitamin-B12 absorption and conventional radiography in 44 patients with inflammatory bowel disease. The retention of SeHCAT was normal in 11 patients with ulcerative colitis but was abnormally low in 9 patients with terminal-ileal resection, 9 out of 14 patients with small-bowel Crohn's disease and in 2 out of 10 patients with Crohn's colitis. The 5 patients with small-bowel Crohn's disease and normal retention had either inactive disease or no radiological evidence of terminal ileal involvement. Measurements of the absorption of vitamin B12 did not discriminate between these groups, and there was very poor correlation between B12 and SeHCAT absorption (r = 0.506, P less than 0.05). There was extremely good correlation of SeHCAT retention measured using a wholebody counter with that measured using an uncollimated gamma camera (r = 0.96, P less than 0.001). The results suggest that SeHCAT retention may prove complementary to conventional methods of assessing small-bowel disease in patients with inflammatory bowel disease. As measurement by gamma camera is feasible, this test can be used in most departments of nuclear medicine.

Colitis, Ulcerative↗
PubMed1985

Anaesthesia and progressive muscular dystrophy.

The presentation and features of Duchenne's progressive muscular dystrophy (Duchenne's PMD) are described and the increased risks associated with anaesthesia are considered. Hazards associated with induction of anaesthesia and immediate postoperative recovery have been stressed in recent case reports, and these are summarized. Features of a hyperpyrexia-like response including cardiac arrest, increased serum creatine phosphokinase concentration, myoglobinuria and metabolic acidosis following suxamethonium or halothane, or both, have been described in patients with Duchenne's PMD. Subsequent in vitro muscle tests have suggested that it is possible that a malignant hyperpyrexia response to general anaesthesia may occur. Six children known to have Duchenne's PMD who developed delayed respiratory insufficiency following anaesthesia and required controlled pulmonary ventilation are reported. In five of the children, cardiac arrest occurred despite apparently adequate respiratory support. Suxamethonium was common to the anaesthetic received by all six patients. In one of these patients subsequent anaesthetics, without suxamethonium, were uneventful and delayed muscle weakness did not occur.

Adolescent↗
PubMed1985

Duodenal mucosa synthesis of prostaglandins in duodenal ulcer disease.

Synthesis of prostaglandins (PGE2, PGI2 and PGF2 alpha) and thromboxane A2 was investigated in short term incubates of duodenal mucosa biopsies. Mucosa close to the ulcer site synthesised significantly less PGF2 alpha (p less than 0.001) and PGI2 (p less than 0.002) measured as its stable metabolite 6-oxo-PGF1 alpha than healthy mucosa from non-ulcer patients. In paired biopsies taken from the ulcer site and opposite the ulcer in the same patient PGF2 alpha and PGI2 syntheses were both significantly and similarly depressed when compared with normal mucosa. Synthesis of PGE2 and TxA2 (as its stable metabolite TxB2) was not different in any tissue. There is a defect in the ability of the human duodenal mucosa in duodenal ulcer disease to synthesise PGF2 alpha and PGI2; the defect is not limited to the ulcer site.

Dinoprost↗
PubMed1985

Acute oxalate nephropathy after massive ascorbic acid administration.

A single 45-g dose of intravenous ascorbic acid, a metabolic precursor of oxalate, was administered to a patient as adjuvant therapy for primary amyloidosis and the nephrotic syndrome. Acute oliguric renal failure occurred. Postmortem histopathologic examination of renal tissue revealed extensive intratubular deposition of crystalline material, which was confirmed as calcium oxalate by a microincineration technique. There were no extrarenal deposits of calcium oxalate. Plasma oxalate and ascorbic acid concentrations were increased. We conclude that therapy with high-dose ascorbic acid is a potential cause of oxalate nephropathy.

Acute Kidney Injury↗
PubMed1984

Reducing overnight secretion of acid to heal duodenal ulcers. Comparison of standard divided dose of ranitidine with a single dose administered at night.

This study was undertaken to assess the clinical usefulness of a single nighttime dose of ranitidine in the short-term healing of duodenal ulcer. One hundred and nine patients with endoscopically diagnosed duodenal ulcer were randomly allocated to treatment with ranitidine, either 150 mg twice daily or 300 mg as a single nighttime dose for four weeks, in a prospective double-blind, double-placebo trial. Of the 102 patients who completed the study, 48 of 57 (84 percent) healed endoscopically on ranitidine 150 mg twice daily, and 43 of 45 (96 percent) healed on 300 mg at nighttime (Mantel-Haenszel test without continuity correction: X2 = 2.9, p = 0.09). One patient treated with ranitidine 150 mg twice daily had a transient episode of cholestatic hepatitis that did not necessitate stopping the drug; in this patient the ulcer healed after 28 days of treatment. There were no other unwanted effects in either group and no significant abnormal biochemical or hematologic changes. This study shows that ranitidine 300 mg given as one nighttime dose is as safe as 150 mg twice daily, and equally as effective. Three hundred milligrams at night appear to confer protection against the adverse effect of smoking in ulcer healing.

Adolescent↗
PubMed1984

Ranitidine 150 mg twice daily vs 300 mg nightly in treatment of duodenal ulcers.

102 patients with endoscopically proven duodenal ulcers were randomly allocated to treatment with ranitidine either 150 mg twice a day or 300 mg every evening for 4 weeks in a prospective double-blind study. The two groups were similar. 48/57 (84%) healed on ranitidine 150 mg twice daily and 43/45 (96%) healed on 300 mg every evening (p = 0.9)--that is, ranitidine 300 mg as a single night time dose is as effective as 150 mg twice daily. The results also indicate the importance of overnight gastric acidity in the pathogenesis of duodenal ulcers.

Adolescent↗