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Biomedical subjects

J E Smith

Publications and source records attributed to J E Smith.

At least 19 recordsLinked to original sources
PubMed1992

Cytotoxic fungal spores in the indoor atmosphere of the damp domestic environment.

Eight-three fungal isolates collected and cultured from the air spora of damp public sector Scottish housing have been screened for cytotoxic properties. A bioassay procedure has been utilised for this purpose involving cytotoxic effects on human embryonic diploid fibroblast lung cells grown as monolayer cultures within the wells of microtitre plates. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] biochemical assay system employed has revealed that 39 (47%) of the moulds investigated possessed spore-associated cytotoxic properties; a value which emphasises the potential health hazards of the continual inhalation of toxigenic fungal propagules by occupants of mouldy houses. Penicillia, the most prevalent fungi found in the internal atmosphere of the domestic environment, accounted for the great majority of cytotoxic strains identified.

Air Microbiology↗
PubMed1992

Production, characterization, and applications of a murine monoclonal antibody to dog erythrocyte antigen 1.1.

A murine IgM monoclonal antibody, which recognizes dog erythrocyte antigen (DEA) 1.1, has been produced. The antibody correctly identified canine RBC possessing DEA 1.1 in a panel of RBC typed by an independent laboratory. Reactivity of the monoclonal antibody was compared with canine anti-DEA 1.1 antiserum with 163 RBC samples from 145 dogs. Results of agglutination tests with the 2 reagents were in agreement for all samples. A card agglutination test that uses the monoclonal antibody with blood is described. A monoclonal antibody-based test should facilitate blood typing for DEA 1.1 in clinical practice.

Agglutination Tests↗
PubMed1992

Methylation sites in Escherichia coli ribosomal RNA: localization and identification of four new sites of methylation in 23S rRNA.

Four previously undetermined sites of methylation are mapped in Escherichia coli 23S rRNA employing a novel combination of methods. First, using a double-isotope approach, the total number of methyl groups in 23S rRNA was determined to be 14.9 +/- 1.6. Second, hybridization of methyl-labeled rRNA to complementary DNA restriction fragments and PAGE analysis were used to purify RNA-DNA heteroduplexes and to quantify methyl groups within specific 23S rRNA fragments. Third, the methylated nucleosides in these fragments were identified and quantified using HPLC, confirming the presence of 14 methylation sites in 23S rRNA, four more than had been previously identified. In contrast, a similar set of analyses conducted on 16S rRNA gave evidence for 10 sites of methylation, at all approximate locations consistent with published 16S methylated nucleoside identities and locations. Selected regions of the 23S rRNA molecule containing previously unidentified methylated nucleosides were released by site-directed cleavage with ribonuclease H and isolated by PAGE. Sites of methylation within the RNA fragments were determined by classical oligonucleotide analyses. The four newly identified methylation sites in 23S rRNA are m2G-1835, m5C-1962, m6A-2503, and m2G at one of positions 2445-2447. Together with previously described sites of modification, these new sites form a group that is clustered in a current model for the three-dimensional organization of the 23S rRNA in the 50S ribosomal subunit, at a locus congruent with nucleotides previously implicated in ribosomal function.

Base Sequence↗
PubMed1992

N-glycolylneuraminic acid and N-acetylneuraminic acid define feline blood group A and B antigens.

Blood group incompatibility causes transfusion reactions and neonatal isoerythrolysis in cats. We investigated the molecular nature of the blood group antigens from cats that had blood type A, B, and AB erythrocytes. Naturally occurring anti-type B antibodies, Triticum vulgaris lectin, monoclonal antibody (MoAb) 32-27, and MoAb R-24 were used in agglutination tests, Western blots, and thin-layer chromatography (TLC) enzyme immunostaining. Type A erythrocytes had NeuGc-NeuGc-Galactose-Glucose-Ceramide ([NeuGc]2GD3) where NeuGc represents N-glycolylneuraminic acid, and NeuAc-NeuGc-GD3, where NeuAc represents N-acetylneuraminic acid, and may have [NeuGc]2 disialylparagloboside and NeuAc-NeuGc-disialylparagloboside. Type B erythrocytes only had [NeuAc]2GD3. Type AB erythrocytes had [NeuGc]2GD3, NeuAc-NeuGc-GD3, and [NeuAc]2GD3. Blood group antigens were also found on a 50-Kd membrane protein. We conclude that type B erythrocytes are characterized by [NeuAc]2GD3 as the only form of this ganglioside and the presence of NeuAc on a 50-Kd membrane protein. NeuGc is the major determinant of the A antigen; specifically, [NeuGc]2GD3 is the major glycolipid form. The A antigen is also present on a 50-Kd membrane protein.

ABO Blood-Group System↗
PubMed1992

Toxoplasma gondii: the role of a 30-kDa surface protein in host cell invasion.

C1E3, a monoclonal antibody recognizing protein P30, a major surface antigen of Toxoplasma gondii tachyzoites, was shown to have a consistent effect on invasion in adult bovine kidney cells. In 10 replicate assays, the overall invasion was reduced to 37% of control values (P less than 0.0001). These results support the role of a functional role for P30 in mediating invasion.

Animals↗
PubMed1992

Paranoid and nonparanoid schizophrenic processing of facially displayed affect.

It was proposed that differences between paranoid and nonparanoid schizophrenics in the processing of affective information may reflect underlying differences in their schema for emotion-laden information. Performances of 14 paranoid schizophrenics, 13 nonparanoid schizophrenics, and 15 matched controls were compared on a facial affect judgment task, and a matched control task comprising geometric figures largely devoid of emotional information. Subjects were required to rate friendliness, select an emotion label, and subsequently to remember the stimuli. Nonparanoids were deficient in overall labeling of facial affect, suggesting a weak cognitive schema for emotional information. The paranoids were particularly more accurate than the nonparanoids at labeling the negative facial affects, suggesting well-developed negative emotional aspects in their cognitive schema. Unexpectedly, nonparanoids relative to paranoids displayed a greater memory deficit in the recognition of geometric figures than in the recognition of faces. The nonparanoid deficit suggests these subjects may have poorly organized schema for remembering less structured nonverbal information. The findings support the idea of fundamental cognitive processing differences between paranoid and nonparanoid schizophrenia.

Adult↗
PubMed1992

Reactivity of lichen lectins with blood typed canine erythrocytes.

Extracts from 69 species of lichens were tested for their ability to agglutinate untreated and enzyme-modified erythrocytes from a panel of blood typed dogs. Forty-three lichen species reacted positively with either untreated or enzyme-modified cells. Many extracts exhibited differential agglutination among red cells tested. The patterns of differential agglutination observed with the lichen extracts did not correspond to known canine blood groups present on the test red cell panel.

Animals↗
PubMed1992

Similarity, identification, and categorization: comment on Ashby and Lee (1991)

Ashby and Lee (1991) tested various models derived from the general recognition theory (GRT; Ashby & Perrin, 1988; Ashby & Townsend, 1986) on their ability to predict and interrelate similarity, categorization, and identification performance. This commentary (a) argues that contrary to Ashby and Lee's suggestion, the likelihood-based GRT cannot generally predict categorization from identification without incorporating selective attention, (b) argues that the categorization rule in the likelihood-based GRT is extremely close in spirit to Nosofsky's (1986) exemplar-based similarity model, (c) reports new model-based analyses that call into question Ashby and Lee's interpretation of their identification-confusion data, (d) raises questions about the identification and similarity models tested by Ashby and Lee, and (e) criticizes Ashby and Lee's methods of fitting and evaluating the various models.

Attention↗
PubMed1992

Secretion of vitamin A and retinol-binding protein into plasma is depressed in rats by N-(4-hydroxyphenyl)retinamide (fenretinide).

In clinical trials the cancer preventive drug N-(4-hydroxyphenyl)retinamide (HPR) markedly lowers plasma concentrations of retinol and retinol-binding protein (RBP). Five hours after injection of HPR (51 mumol/kg), serum concentrations of retinol and RBP were 33 and 42% lower, respectively, than control values in rats. Because the mean transit time for retinol disappearance from serum of HPR-treated rats (1.9 h) was similar to that for radiolabeled retinol in control rats in previous studies, plasma retinol turnover is apparently not accelerated by HPR treatment. To study the effects of HPR on the secretion of the retinol-RBP complex from liver, control or HPR-treated rats were injected with chylomicrons containing [3H]vitamin A and [14C]triglycerides. Both labels were rapidly cleared from plasma in the two groups. In control rats [3H]retinol concentrations began to increase in plasma after 30 min due to liver secretion of retinol bound to RBP. In HPR-treated rats, secretion was apparently inhibited because the amount of [3H]retinol bound to RBP at 4.66 h was only 2.6% of the control level. We conclude that HPR partially blocks the secretion of the retinol-RBP complex from liver and other tissues, and thus depresses plasma concentrations of vitamin A and RBP.

Animals↗
PubMed1992

Effect of fentanyl on the circulatory responses to orotracheal fibreoptic intubation.

The effectiveness of fentanyl in attenuating the pressor and heart rate response to orotracheal fibreoptic intubation under general anaesthesia was assessed in 60 healthy patients undergoing elective surgery. Patients were randomly assigned to receive either fibreoptic intubation with or without fentanyl 6 micrograms.kg-1 or traditional Macintosh intubation with fentanyl 6 micrograms.kg-1. A standardised general anaesthetic was administered which included temazepam premedication, thiopentone, atracurium, oxygen, nitrous oxide and isoflurane. The pressor response to fibreoptic intubation was suppressed in those patients who received fentanyl and was similar to that seen in the Macintosh-fentanyl group of patients. The heart rate response to fibreoptic intubation was also significantly reduced in the patients who received fentanyl, but, in contrast, was still significantly greater than that in the Macintosh-fentanyl group. Fentanyl 6 micrograms.kg-1 appears to have a useful place in attenuating the cardiovascular effects of fibreoptic intubation under general anaesthesia.

Adolescent↗
PubMed1992

Ultrastructural findings in congenital anemia, dyskeratosis, and progressive alopecia in Polled Hereford calves.

Ultrastructural evidence of dyserythropoiesis was found in ten calves (ages 1 to 16 months) previously diagnosed as having congenital anemia, dyskeratosis, and progressive alopecia. Morphologic abnormalities found in erythroid precursors of all calves were associated with the nucleus. Rubriblast nuclei were irregular with numerous blebs, indentations, and deep clefts. Elongated blebs appeared as satellite nuclei in some sections. Nuclear membranes had numerous defects or gaps, which were frequently present in, but not limited to, recently divided cells. Cytoplasmic material could be found within these gaps and extending into the nucleus. Rubricytes had chromatin that was abnormally condensed and hyperosmiophilic, with numerous translucent vacuoles present. Binucleate rubricytes occurred frequently in affected calves. These changes resemble those of type I congenital dyserythropoiesis in human beings, and we suggest congenital anemia, dyskeratosis, and progressive alopecia of Polled Hereford calves as the appropriate diagnostic terms to describe this disease.

Alopecia↗
PubMed1992

Congenital dyserythropoiesis and progressive alopecia in Polled Hereford calves: hematologic, biochemical, bone marrow cytologic, electrophoretic, and flow cytometric findings.

Congenital dyserythropoiesis with dyskeratosis is a slow, progressive, and often fatal disease in Polled Hereford calves. Affected calves have a macrocytic normochromic anemia with a mild reticulocytosis. Studies indicate that calves are hyperferremic with increased saturation of serum total iron binding capacity, which rules out iron deficiency as a cause. Other secondary causes of dyserythropoiesis, including cobalamin and folate deficiencies, are unlikely because serum cobalamin and folate levels of affected calves were normal. Virus isolation was negative, and failure to identify bovine retroviral antigens or antibodies from several calves suggested that viral agents were not involved. Bone marrow cytologic findings were similar to those in congenital hereditary dyserythropoiesis in humans and included occasional multinucleate cells, internuclear chromatin bridging between nuclei of partially divided cells, and, more frequently, irregular nuclear shapes and chromatin patterns. DNA content and cell cycle distribution of erythroid cells appeared normal, and no electrophoretic abnormalities were detected in erythrocyte membrane proteins. The Polled Hereford syndrome is similar in many ways to type I congenital dyserythropoiesis in humans and may be an appropriate biomedical model for studying erythroid proliferation during dyserythropoiesis.

Alkaline Phosphatase↗
PubMed1992

Implant and copper oxide needles for steers grazing Acremonium coenophialum-infected tall fescue pastures: effects on grazing and subsequent feedlot performance and serum constituents.

Two experiments were conducted to compare the effects of a progesterone-estradiol implant (PEI) with no implant (NI) and 20 g of copper oxide needles (CuON) with no CuON on grazing, subsequent feedlot performance, and selected serum constituents of steers. In Exp. 1, 114 Limousin crossbred yearling steers (317 kg average initial BW) were stocked continuously on Acremonium coenophialum-infected tall fescue (Festuca arundinacea Schreb.)-ladino clover (Trifolium repens L.) pastures (C) or were rotated to bermuda grass (Cynodon dactylon [L.] Pers.) during summer months (R) of two consecutive years. Implant and copper treatments were applied within pasture. Blood samples were collected four times during each grazing season. Continuously stocked steers had greater (P less than .05) grazing gain, less (P less than .10) feedlot gain, and heavier (P less than .05) carcass weights than R steers did. Implanted steers had greater (P less than .05) pasture but lesser (P less than .05) feedlot gains than did NI steers. Prolactin concentrations were greater (P less than .05) from R than from C steers in late summer 1988. Ceruloplasmin was greater (P less than .01) with CuON than without on the last three and last two sampling dates in 1988 and 1989, respectively. In Exp. 2, blood samples were collected twice from 40 mixed-breed steers (283 kg average initial BW) receiving the same implant and copper treatments as in Exp. 1 and grazing infected fescue for one season. Serum ceruloplasmin and copper concentrations were increased (P less than .01) by CuON, but other measurements did not differ among treatments. Summer grazing of bermuda grass increased serum copper, ceruloplasmin, and prolactin but decreased grazing performance. Implanting increased grazing performance. Copper oxide needles increased serum ceruloplasmin and copper concentrations but did not affect steer performance.

Animal Feed↗
PubMed1992

Pharmacologic evaluation of factor XIIIa*-like enzyme activity in equine plasma as a potential therapeutic avenue for the inhibition of fibrinous tissue.

Several pharmaceutical compounds were evaluated for their ability to selectively inhibit activated coagulation factor-XIII-like enzyme activity (eg, XIIIa*) in pooled equine plasma. Presence of coagulation factor-XIIIa*-like enzyme activity in plasma was established by assay procedures involving incorporation of the fluorescent amine compound, monodansylcadaverine, into purified casein, which served as a protein substrate. Pharmaceuticals inhibitory to coagulation factor-XIIIa*-like enzyme activity were recognized by plasma gel formation of high spectrophotometric transmittance (transparency), solubility of transparent fibrin gels in concentrated urea solution, in conjunction with simultaneous depletion of native fibrinogen fractions, and production of fibrin monomer. Compounds acting primarily as anticoagulants were recognized by lack of plasma gel formation, but retaining high spectrophotometric transmittance and no detectable depletion of native fibrinogen fractions. Compounds failing to inhibit either thrombin-mediated fibrinogen-fibrin transformation (ie, coagulation) or coagulation factor-XIIIa*-like enzyme activity were recognized by opaque plasma gels caused by fibrin polymerization, low spectrophotometric transmittance values, and coinciding with depletion of native fibrinogen fractions. Pharmaceuticals capable of exerting selective inhibition of coagulation factor-XIIIa*-like enzyme activity were further classified as competitive inhibitors of phase 1 (carbamide) or phase 2 (terminal amine) of the transglutamination process.

Analysis of Variance↗
PubMed1992

Additive and synergistic pharmacologic inhibition of equine fibrinoligase (factor XIIIa*-like) biochemical activity.

A selected group of pharmaceutical compounds were evaluated for the ability to inhibit the biochemical activity of fibrinoligase (coagulation factor XIIIa*) in pooled equine plasma. Criteria for the pharmaceuticals selected were based on the mechanism of the transglutamination biochemical reaction mediated by coagulation factor XIIa*. These criteria were complemented by recognition of the molecular configuration and chemical composition of amino acid residue side chains involved in the process of covalent fibrin monomer polymerization (cross-linking, transglutamination) mediated by this enzyme. Each pharmaceutical was evaluated individually and in combination with other potential coagulation factor XIIIa* inhibitors in an effort to detect additive and synergistic phenomenon. In this context, pharmaceuticals with a carbonylamide (eg, cefuroxime, Girard's reagent-P, prolinamide) were applied in concert with compounds with a terminal amine (eg, D-arginine, L-lysine) functional group. In concept, this method theoretically served to competitively simulate glutamine and lysine amino acid residues within strands of fibrin monomer substrate involved in phase I (carbonylamide) and phase II (terminal amine) of the transglutamination reaction (covalent fibrin monomer cross-linking). Halogen-dinitro and ethylene compounds were also evaluated because of their reported ability to inactivate enzyme systems dependent on an intact sulfhydryl group located at their biochemically active site (eg, cystine amino acid residue). This group of pharmaceutical compounds failed to inhibit the biochemical activity mediated by coagulation factor XIIIa* in equine plasma.

Animals↗