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Biomedical subjects

E Segal

Publications and source records attributed to E Segal.

186 records · Page 11Linked to original sources
PubMedDate not supplied

In vitro and in vivo adherence of Candida albicans to mucosal surfaces.

In continuation of a previous study, chitin soluble extract (CSE) and anti-Candida albicans antibodies were found to inhibit the in vitro adherence of C. albicans to human vaginal epithelial cells by 60-70%. Pretreatment of epithelial cells with chitin, CSE or N-acetyl-glucosamine (NAG) decreased the percentage of adherence, while pretreatment of yeasts had no such effect, indicating that chitin or its derivatives may be involved in mediating the adherence of C. albicans. In vivo attachment of C. albicans to epithelial cells was studied in an experimental murine vaginitis created by inoculating mice intravaginally with yeasts at the oestrus stage. Attachment of the yeasts to exfoliated vaginal epithelial cells was followed microscopically, and the course of infection was assessed histopathologically in tissue sections at various times post-yeast inoculation. The infection rate at 24-h post-yeast inoculation was approximately 50%. Attempts were made to block in vivo attachment and prevent infection by pretreating 208 mice with either CSE, NAG, mannan or phosphate-buffered saline (PBS) prior to inoculation with yeasts. The infection rate among mice pretreated with mannan or PBS was 41.6% and 43.8%, respectively. Among CSE- or NAG-pretreated animals, the rate ranged from 0-9%. Treatment of mice with CSE or NAG after inoculation of the yeasts did not prevent infection. The data from the in vivo experiments reveal that pretreatment of animals with chitin derivatives blocks attachment of yeasts to the vaginal mucosal surfaces and leads to the prevention of vaginal infection in an experimental model.

Adhesiveness↗
PubMedDate not supplied

Intragenic recombination leads to pilus antigenic variation in Neisseria gonorrhoeae.

The pilus of the bacterium Neisseria gonorrhoeae is a fimbriate surface structure which promotes attachment of the bacterium to host epithelial cells. Gonococcal pilus phase variation is characterized by a rapid on/off switch in which piliated (P+) cells throw off non-piliated (P-) variants and vice versa. Two regions of the gonococcal chromosome (pilE1 and pilE2) act as pilin expression loci, reminiscent of the MAT locus in the yeast Saccharomyces cerevisiae, while several other chromosomal regions contain silent (non-expressing) pilin sequences. Biochemical and antigenic diversity is seen in pili from a wide variety of clinical isolates. Pilins (pilus subunits) are composed of conserved N-terminal and variable C-terminal regions; the conserved region of gonococcal pilin is also found in pilins produced by widely disparate bacteria. We show here that the gonococcal pilin undergoes antigenic variation in vitro and in vivo. The protein consists of constant, semi-variable and hypervariable regions. This antigenic variation probably involves gene conversion of mini-cassettes of pilin information.

Amino Acid Sequence↗
PubMedDate not supplied

Induction of candidal vaginitis in diabetic mice and attempts to prevent the infection.

In the present study on the induction and prevention of candidal vaginal infection in diabetic mice, ICR female mice were rendered diabetic by intraperitoneal injections of 160 mg kg-1 streptozotocin (SZ) which induced a stable non-lethal diabetic state apparent 2-7 days post-SZ injection. Diabetic mice and non-diabetic controls were inoculated intravaginally with 10(7)-10(10) Candida albicans yeasts. Infection was evaluated by the number of infected mice 3 days post-inoculation and the rate of clearance of infection during a 35-day follow-up. All C. albicans doses investigated induced vaginal infection in the diabetic mice, while in the non-diabetic controls only 40% of those inoculated with the lower (10(7) CFU) dose developed infection. The yeast load in the diabetic mice was 10-fold higher than in the controls and the duration of infection was longer. In an attempt to prevent infection intravaginal treatment with 5-40 mg of a chitin derivative (CSE) mouse-1 was given prior and pre- and post-inoculation with C. albicans. The optimal CSE treatment regimen was both pre- and post-administration of 10 or 20 mg CSE mouse-1 which significantly reduced the number of infected animals and also the duration of infection.

Administration, Intravaginal↗
PubMedDate not supplied

Adhesion of Candida albicans to epithelial cells--effect of nikkomycin.

This study investigated the effect of the chitin synthetase inhibitors, the nikkomycins (NZ and NZ+NX), on Candida albicans adhesion to buccal epithelial cells (BECs) in vitro. The effect was expressed in reduced chitin synthetase activity and chitin content of fungal cells. In vitro adhesion assays to BECs of Candida exposed to NZ and NZ+NX revealed reduced adhesion values. Light, scanning and transmission electron microscopy (SEM, TEM) of NZ-treated and untreated micro-organisms showed changed fungal morphology and reduced adherence of the treated yeasts. Scanning electron microscopy of NZ-treated C. albicans labelled with gold-conjugated wheatgerm agglutinin (WGA) revealed less labelling than in the untreated organisms. A close contact between the fungus and the epithelial cell at a site with intense WGA-gold labelling was noted in TEM experiments. The data point to the involvement of chitin in the adhesion of C. albicans to epithelial cells.

Adult↗
PubMedDate not supplied

Outcome of patients with scleroderma admitted to intensive care unit. A report of nine cases.

OBJECTIVE: Patients with systemic rheumatic disease constitute a small percentage of admissions to the medical intensive care units (ICUs). Systemic sclerosis (SSc) is one of the rheumatic diseases that together with secondary complications may lead to a critical illness requiring hospitalization in the ICU. We present the features, clinical course and outcome of critically ill patients with scleroderma that were admitted to the ICU. METHODS: The medical records of nine patients with diagnosis of scleroderma (8 female, 1 male), admitted to the intensive care unit of Sheba Medical Center during the 11-year interval between 1991 and 2002, were reviewed. RESULTS: The mean age of the patients at the time of admission to the ICU was 48 +/- 13 [SD] years. The mean duration of SSc from diagnosis to the ICU admission was 8 +/- 8 years. Six patients had diffuse SSc, two patients had limited SSc and one patient had juvenile diffuse morphea. The main reasons for admission to the ICU were: infection/ septic syndrome (n = 4), scleroderma renal crisis (SRC) with pulmonary congestion (n = 2), acute renal failure associated with diffuse alveolar hemorrhage namely scleroderma- pulmonary - renal syndrome (SPRS) (n = 1), iatrogenic pericardial tamponade (n = 1), mesenteric ischemia (n = 1). The patients had high severity illness score (mean APACHE II 25 +/- 3). Eight out of nine patients (89%) that were admitted to the ICU died during the hospitalization, six (66.6%) of them died in the ICU. Septic complications as the main cause of death were determined in five patients (62.5%), while four of them had pneumonia and acute respiratory failure along with underlying severe pulmonary fibrosis. Lungs and kidneys were the most common severely affected organs by SSc in our patients. CONCLUSION: The outcome of scleroderma patients admitted to the ICU was extremely poor. Infectious complication was the most common cause of death in our patients. Although infections are treatable, the high mortality rate for this group of patients was dependent on the severity of the underlying visceral organ involvement, particularly severe pulmonary fibrosis. The severity of this involvement is a poor outcome predictor. An early diagnosis and an appropriate treatment of such complications may help to reduce the mortality in scleroderma patients.

Adult↗