Biomedical subjects

S Jackman

Publications and source records attributed to S Jackman.

7 recordsLinked to original sources

PubMed1998

Effect of gliotoxin on human polymorphonuclear neutrophils.

OBJECTIVES: Candida albicans is known to produce gliotoxin, which has several prominent biological effects, including immunosuppression. Interference with host defenses may arise from the effects of this toxin on leukocyte structure and function. METHODS: Flow cytometric analysis revealed that polymorphonuclear leukocytes (PMN) were more sensitive to gliotoxin than were mononuclear cells. Structural and various functional aspects of PMN exposed to gliotoxin were studied. RESULTS: Gliotoxin at (1 microgram/mL) did not affect the viability but did diminish PMN chemotaxis and reduced their ability to ingest particles. Other functional aberrations included decreased nitroblue tetrazolium dye reduction, decreased superoxide production, and release of lactoferrin suggesting by degranulation. Gliotoxin also affected the ability of PMN to kill Escherichia coli. CONCLUSIONS: This study suggests a previously unrecognized potential virulence factor of C. albicans that could contribute to persistence of yeast colonization or recurrence of symptomatic infection through diminished host resistance.

Candida albicans↗

PubMed1998

Human vaginal mucosal immune system: characterization and function.

OBJECTIVE: The mucosal immune system has been recognized as the first line of defense against foreign antigens. The limited information available on the mucosal immunity of the lower reproductive organs have restricted our ability to fight infections, especially, the sexually transmitted disease. The aim of this study was to characterize in-vitro the human vaginal lamina propria lymphocytes (VLPL), their cell surface phenotypes, and cellular function. METHODS: VLPL were isolated from human vaginal mucosa by enzymatic techniques. Cell surface characteristics were investigated by immunohistochemistry and flow cytometric analysis. Cellular immune function was evaluated by 3H-thymidine incorporation studies and ornithine decarboxylase (ODC) activity. RESULTS: Immunohistochemistry and flow cytometric analysis showed that the CD4/CD8 ratio of the human vaginal mucosa is reversed compared to the gut lamina propria lymphocytes (0.55 +/- 0.17). PHA and ConA mitogens enhanced VLPL thymidine incorporation, while PWM did not have any significant effect. Very high level of ODC activity was observed in VLPL after PHA stimulation. CONCLUSIONS: The human VLPL can be isolated, characterized, and respond to a mitogenic stimulus. We postulate that further analysis of the vaginal immune system will enhance our understanding of local defence mechanisms which will help in the development of new therapeutic modalities against vaginal infections.

CD4-CD8 Ratio↗

PubMed1996

Appendicitis complicating pregnancy.

Abdominal pain is a common symptom in pregnancy. Its etiology is diverse and diagnosis often poses a problem. Inflammatory disorders of extra-uterine origin such as appendicitis should always be considered as a possible cause. Three cases of appendicitis complicating pregnancy managed at the Queen Elizabeth Hospital, Barbados during the year 1993 are documented. Two presented in the antenatal period and the third postpartum. The clinical manifestations and the difficulties encountered in diagnosis are emphasised.

Adult↗

PubMed1991

Crystallization and preliminary X-ray analysis of phosphoporin from the outer membrane of Escherichia coli.

Phosphoporin is a pore-forming transmembrane protein that spans the outer membrane of Escherichia coli and facilitates the diffusion of phosphates and phosphorylated compounds. Phosphoporin has been crystallized in several different crystal forms, although only one appears to be suitable for X-ray analysis. These crystals, which are hexagonal plates, diffract X-rays to 3 A resolution and belong to the space-group P6(3)22, with unit cell dimensions a = b = 121 A and c = 111 A.

Bacterial Outer Membrane Proteins↗

PubMed1991

Nicotinic pharmacology of anatoxin analogs. II. Side chain structure-activity relationships at neuronal nicotinic ligand binding sites.

Eighteen analogs of (+)-anatoxin-a were evaluated for nicotinic potency at two putative nicotinic acetylcholine receptor sites in the central nervous system. The affinities of the analogs for [3H]nicotine and [125I]alpha-bungarotoxin binding sites were compared. This series of analogs, with modifications to the side chain moieties of the parent structure, enables the importance (for nicotinic binding) of hydrogen bonding strength, planarity, size and steric configuration of this region of the molecule to be assessed. These studies confirm the importance of the side chain stereochemistry and the subordinate role of H-bonding strength of anatoxin analogs. Of all the analogs tested, the parent compound (+)-anatoxin-a is the most potent competitor of ligand binding. Although all analogs have higher affinity at the [3H](-)-nicotine site compared to the alpha-[125I]bungarotoxin site, the rank order of potency is generally the same at both central nervous system sites, and agrees with the order at the muscle nicotinic receptor. However, the simple methoxyamide and the isoxazolidide analogs appear more selective for the neuronal nicotinic receptor subtype identified by [3H](-)-nicotine, indicative of structural differences among the agonist recognition sites.

Animals↗

PubMed1990

Results of surgical treatment of neonatal necrotizing enterocolitis.

In 6 years, 74 neonates were treated for necrotizing enterocolitis, 40 (54 per cent) of whom underwent operation. The early postoperative mortality rate was 23 per cent and there was one late death. Of the 30 postoperative survivors, two have short bowel syndrome, two have chronic respiratory disease, two are partially sighted, and five (17 per cent) have severe developmental delay. Only 15 (50 per cent) survivors enjoy good health.

Abnormalities, Multiple↗

PubMed1988

A lesson in intestinal atresias.

A girl with an atresia of the distal ileum and another in the sigmoid colon is reported, as are the inadequacies in her management. The association of an ileal atresia with a separate colonic atresia does not seem to have been previously reported.

Colon↗