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Biomedical subjects

L Hall

Publications and source records attributed to L Hall.

At least 109 records · Page 6Linked to original sources
PubMed1994

Production of cytokines by lymphocytes from spleen, mesenteric lymph node and intestinal lamina propria of pigs.

Large numbers of cells can be recovered from pig intestine with phenotypes suggesting lamina propria rather than intraepithelial origin. Following activation with concanavalin A these cells produced a T-cell growth factor (TCGF) activity which was not inhibited in the presence of a monoclonal antibody recognizing pig interleukin-2 receptors (IL-2R). In contrast, the activity of recombinant human IL-2 and of supernatants from activated spleen cells was almost entirely inhibited by anti-IL-2R. The failure of anti-IL-2R to inhibit the activity of lamina propria-derived TCGF was not apparently owing to interference by soluble receptor with binding of monoclonal to target blast cells as no effect of supernatants on binding was observed. The results suggest that cells derived from the pig intestinal lamina propria fail to produce IL-2 following polyclonal activation in vitro. Consistent with this finding, IL-2 transcripts could be detected by polymerase chain reaction (PCR) following reverse transcription of mRNA derived from spleen and from mesenteric lymph node but not lamina propria lymphocytes, while IL-4 cDNA could be detected from all three sources.

Animals↗
PubMed1993

Cloning of cDNA for the beta-subunit of rabbit translation initiation factor-2 using PCR.

RNA was isolated from rabbit liver and used to direct the synthesis of total cDNA. Rabbit eIF-2 beta transcripts were then specifically amplified by PCR and sequenced. RACE (rapid amplification of cDNA ends) was used to obtain 3' and 5' sequences. Comparison of the deduced amino acid sequence with that of human eIF-2 beta reveals a very high degree of sequence identity.

Amino Acid Sequence↗
PubMed1993

Molecular cloning and deduced amino acid sequences of the gamma-subunits of rat and monkey NAD(+)-isocitrate dehydrogenases.

A 600 bp cDNA fragment encoding part of the gamma-subunit of pig heart NAD(+)-isocitrate dehydrogenase (ICDH gamma) was amplified by PCR using redundant oligonucleotide primers based on partial peptide sequence data [Huang and Colman (1990) Biochemistry 29, 8266-8273]. This PCR fragment was then used as a probe to isolate clones encoding the complete mature forms of the gamma-subunit from rat epididymis and monkey testis cDNA libraries. Comparison of the deduced amino acid sequences of the rat and monkey subunits and the partial sequence of the pig heart enzyme revealed a remarkably high level of sequence identity. The relationship between the deduced amino acid sequences of the NAD(+)-ICDH gamma-subunits and those of nonmammalian NAD(+)- and NADP(+)-ICDH subunits is discussed.

Amino Acid Sequence↗
PubMed1993

Isolation and characterization of a rat cDNA clone encoding a secreted superoxide dismutase reveals the epididymis to be a major site of its expression.

Superoxide dismutase (SOD) plays a key role in combating loss of fertility of spermatozoa due to lipid peroxidation. Here we report the sequence of a cDNA encoding a secreted form of SOD isolated from a rat epididymal library. Northern-blot analysis indicates that the corresponding transcript is expressed principally in the cauda region of the epididymis, consistent with the high levels of SOD enzyme activity found in cauda-epididymidal plasma. Much lower levels of an identically sized transcript exist in all tissues examined, including placenta. PCR and subsequent sequence analysis of rat placental SOD strongly suggest that it is identical in sequence with epididymal SOD.

Amino Acid Sequence↗
PubMed1993

Sequence analysis of monkey acrosin-trypsin inhibitor transcripts and their abundant expression in the epididymis.

Seven independent cross-hybridizing clones have been isolated from a Macaca fascicularis epididymal cDNA library and their inserts shown to correspond to a secreted inhibitor of the sperm serine proteinase, acrosin. Hybridizing transcripts of approx. 0.6 kb have been shown by Northern blot analysis to be considerably more abundant in the epididymis than the testis. This finding is in surprising contrast to a previous report that human acrosin-trypsin inhibitor mRNA predominates in the testis.

Amino Acid Sequence↗
PubMed1993

Nucleotide and deduced amino acid sequence of porcine interleukin 4 cDNA derived from lamina propria lymphocytes.

Total RNA was isolated from in vitro activated lamina propria lymphocytes and used to direct the synthesis of cDNA. Interleukin 4 transcripts were then specifically amplified by PCR. Comparison of the nucleotide sequence with its human homologue demonstrates deletion within the coding region of pig interleukin 4 centred around amino acid residue 70 in the mature human protein.

Amino Acid Sequence↗
PubMed1993

Spontaneous dissection of the abdominal aorta: experience with five patients.

Spontaneous dissection of the infradiaphragmatic abdominal aorta is a rare form of aortic dissection. Its natural history and management are not well defined. We have recently treated five patients with spontaneous aortic dissection. Two patients had acute dissections and three had chronic dissections. Three patients developed saccular aneurysms and underwent resection. Two patients had stable dissections and were treated medically. All patients are alive and well at 6 months to 5 years. We think that spontaneous aortic dissection can be treated as a variant of type III dissection with initial medical management, reserving surgery for those patients in whom a saccular aneurysm or a complication of the dissection develops.

Aged↗
PubMed1993

Inter-relationships between inflammatory mediators released from colonic mucosa in ulcerative colitis and their effects on colonic secretion.

Metabolites of arachidonic acid have been implicated in the pathophysiology of ulcerative colitis-they can stimulate intestinal secretion, increase mucosal blood flow, and influence smooth muscle activity. The influence on the mucosal transport function of culture medium in which colonic mucosal biopsy specimens had been incubated was investigated using rat stripped distal colonic mucosa in vitro as the assay system. Colonic tissue from patients with colitis and from control subjects was cultured. Medium from inflamed tissue contained more prostaglandin E2 (PGE2) and leukotriene D4 (LTD4) and evoked a greater electrical (secretory) response in rat colonic mucosa than control tissue medium. In inflamed tissue, cyclo-oxygenase inhibition (indomethacin) attenuated PGE2 but increased LTD4 production; conversely lipoxygenase inhibition (ICI 207968) inhibited LTD4 production but enhanced PGE2 output. Each inhibitor alone enhanced the electrical response in the rat colon. Inhibition of both enzymes (indomethacin plus ICI 207968) caused a fall in both PGE2 (82%) and LTD4 (89%) production and in the electrical response (57%). Inflamed tissue treated with a phospholipase A2 inhibitor (mepacrine) produced less PGE2, LTD4, and electrical responses when compared with inflamed tissue, either untreated (91%, 92%, and 79% respectively) or treated with cyclo-oxygenase and lipoxygenase inhibition. Incubation with bradykinin stimulated eicosanoid release and electrical response, while a bradykinin antagonist caused a modest inhibition. Analysis of these observations suggests that a combination of arachidonic acid derivatives accounts for about half the secretory response. Other products of phospholipase A2 activity are probably responsible for much of the remainder, leaving up to 20% the result of types of mediator not determined in this study.

Adult↗
PubMed1993

Hepato-renal toxicosis characterized in sheep dosed intraruminally with snakeweed foliage (Gutierrezia spp).

To investigate the acute effects of snakeweed foliage (SW, Gutierrezia spp), 6 ruminally fistulated wethers (avg BW 78.6 kg) were dosed intraruminally (2/dose) with 454 g ground SW foliage, 227 g SW + 227 g alfalfa, or 454 g alfalfa daily for 5 d. Rumen fluid and blood samples were collected daily before SW dosage, and on day 6 the animals were euthanized and examined. At d 5, SW increased direct and indirect bilirubin indicating impaired hepatocyte function with biliary involvement and cholestasis. Gamma-glutamyl transpeptidase concentrations were elevated, and pale yellowish enlarged livers were observed in SW-dosed animals. Serum creatinine concentrations were increased 2-fold by SW, suggesting renal impairment. Rumens from dosed animals were compacted with hemorrhagic and necrotic mucosa suggesting SW-impaired rumen motility and microbial fermentation. One wether dosed with 454 g SW died after SW dosage for 2 d.

Animals↗
PubMed1992

Identification of an abundant monkey epididymal transcript encoding a homologue of human CAMPATH-1 antigen precursor.

A number of cDNA clones encoding a small (0.5-0.6 kb) transcript have been isolated from a monkey (Macaca fascicularis) epididymal cDNA library. DNA sequence analysis indicates that this abundant epididymal transcript is homologous to the human CAMPATH-1 (CDw52) antigen precursor, a GPI-anchored membrane glycoprotein previously described on lymphocytes and monocytes.

Amino Acid Sequence↗
PubMed1992

A mammalian epididymal protein with remarkable sequence similarity to snake venom haemorrhagic peptides.

Following spermatogenesis in the testis, mammalian spermatozoa pass into the epididymis, where they undergo changes which confer on them forward motility and the ability to recognize and penetrate the egg. Many of these maturation events involve androgen-regulated epididymal proteins which become associated with the sperm membrane, and/or effect changes to integral sperm membrane proteins. Here we report the sequence of an 89 kDa androgen-regulated protein from rat (Rattus norvegicus) and monkey (Macaca fascicularis) epididymis that is synthesized exclusively in the caput region and is localized on the apical surface of its principal epithelial cells. This protein shows remarkable similarity to a variety of proteases and disintegrins found in snake venoms and is similar to, but distinct from, the guinea-pig sperm surface PH-30 alpha/beta complex recently implicated in sperm-egg recognition and fusion.

ADAM Proteins↗
PubMed1992

Genetic evidence for an androgen-regulated epididymal secretory glutathione peroxidase whose transcript does not contain a selenocysteine codon.

Epididymal glutathione peroxidase (GPX) has been suggested as a major factor in combating loss of fertility of spermatozoa due to lipid peroxidation. We report here the isolation and sequence of putative GPX cDNAs from rat (Rattus rattus) and cynomolgus-monkey (Macaca fascicularis) epididymis, which exhibit marked sequence identity with known GPXs. In both species the cDNAs encode predicted preproteins containing 221 amino acid residues. Unlike other characterized GPX sequences, epididymal GPX mRNA does not contain a selenocysteine codon (UGA). However, sequence comparison and molecular-modelling studies suggest a high degree of structural conservation between epididymal and other GPXs. Transcripts corresponding to epididymal GPX are not detected in a variety of other tissues (liver, spleen, kidney and testis) and appear to be androgen-regulated in the epididymis.

Amino Acid Sequence↗