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Biomedical subjects

E Balish

Publications and source records attributed to E Balish.

At least 145 records · Page 8Linked to original sources

Effect of systemic candidiasis on blastogenesis of lymphocytes from germfree and conventional rats.

Germfree and conventional rats were challenged (intravenously) with Candida albicans and sacrificed at various times after infection, and their spleen cells were harvested to examine the effect of disseminated candidiasis on in vitro lymphocyte hypersensitivity to Candida antigens (CA). Results showed that conventional rat splenocytes, initially responsive in vitro to stimulation by CA, manifested a depression in CA-specific responsiveness after challenge with viable C. albicans (days 3 to 6 postchallenge). In addition, the latter splenocyte response to phytohemagglutinin (PHA) and concanavalin A (ConA) was suppressed by 3 to 6 days after challenge with Candida. In contrast to conventional rats, the response of germfree rat splenocytes to CA was insignificant before challenge with C. albicans, and it was increased at 9 days after infection. The response of uninfected germfree rat splenocytes to PHA and ConA was significantly lower than that of unchallenged conventional rats. Challenge with viable C. albicans did not result in a suppression of gnotobiotic rat splenocyte responses to PHA and ConA, but rather, the disseminated infection resulted in as much as fivefold increases in PHA or ConA-induced blastogenesis. These findings suggest that disseminated candidiasis is capable of suppressing blastogenesis in immunologically mature conventional rats and of improving lymphocyte blastogenesis from immunologically immature germfree rats.

Aging↗

Postbacterial sepsis and disseminated candidiasis.

The effect of gram-negative sepsis (Escherichia coli) on the capacity of polymorphonuclear leucocytes (PMN) to phagocytize and kill Candida albicans was assessed. The PMN's from septic dogs phagocytized C. albicans as well as PMN's from non-septic dogs. The PMN's from septic dogs that phagocytized C. albicans underwent a spontaneous lysis at a much higher rate than PMN's from non-septic dogs. A functional difference in PMN's from normal and septic dogs is indicated.

Animals↗

Endotoxin in germfree, gnotobiotic, or conventional-flora Sprague-Dawley rats.

The Limulus assay for bacterial endotoxin was performed on serum and (or) plasma from animals monoassociated with Clostridium species, Staphylococcus aureus, Escherichia coli, Proteus mirabilis, Enterobacter agglomerans, Bacteroides fragilis, Klebsiella pneumoniae, or Candida albicans. Plasma from animals monoassociated with the gram-negative bacteria or C. albicans consistently showed a positive Limulus test while conventional-flora controls, germfree rats, and gnotobiotic animals monoassociated with gram-positive bacteria or E. agglomerans were negative. Germfree and conventional rats were injected (intraperitoneal (i.p.)) with Salmonella typhosa lipopolysaccharide (LPS). Although no endotoxin was detectable in either group prior to the injection, by 1 h post injection endotoxin was in the plasma of all groups. The germfree rats appeared to clear the LPS quicker than their conventional-flora counterparts. Generally, LPS-injected rats (conventional and germfree) showed clumping and decreased number of platelets, a decrease in their lymphocyte counts, and increased polymorphonuclear leukocyte (PMN) counts.

Animals↗

Clinical experience with prophylactic antibiotic bowel suppression in burn patients.

An oral prophylactic antibiotic regimen (neomycin-erythromycin-nystatin) aimed at suppression of the bowel flora was utilized in 20 patients with thermal injury treated in a laminar flow burn unit with strict sterile technique and reverse isolation. The regimen was utilized for an average of 24 days. Surface cultures were obtained twice weekly from multiple areas of the burn wound, and burn wound biopsies were performed one to two times weekly. These patients were compared prospectively with a group of 10 patients treated in otherwise identical fashion, save for the omission of the antibiotic suppressive regimen. Bacterial colonization of the burn wound occurred an average of 19 days after admission in the group receiving antibiotics compared to 4 days after admission in the control group (p less than 0.01). Positive burn biopsies (more than 10(5) bacteria per gm of tissue) were observed twice as often in the group not receiving antibiotics (p less than 0.16) as were infectious complications of several types: bacteremia, burn wound sepsis, urinary tract infections, pneumonitis, cellulitis (0.10 less than p less than 0.20). Staphylococcal or fungal overgrowth were not encountered in the patients receiving prophylactic antibiotics, nor was there an adverse effect on serum creatinine levels with the prolonged use of neomycin.

Adolescent↗

Effect of immunization of bacterial adherence to urothelium.

In order for a urinary tract infection to begin, the pathogenic bacteria must first adhere to the urothelial surface. An in vivo method for quantitation of bacterial adherence to urothelium has been developed. Immunization by instillation of bacterial antigens into the rat bladder decreased bacterial adherence. Bladder immunization was more effective than subcutaneous immunization. Preinfection by Escherichia coli decreased subsequent adherence of Klebsiella pneumoniae. Increasing antiadherence factors may offer a new approach to the treatment of recurrent urinary tract infections.

Adhesiveness↗

Effect of age, sex, and intestinal flora on the induction of colon tumors in rats.

Germfree and conventional Sprague-Dawley rats were assessed for their susceptibility to intrarectally injected N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or N-methyl-N-nitrosourea (MNU). Adenocarcinoma of the colon was induced in germfree and conventional rats by both MNNG and MNU. The colons of germfree rats were more susceptible to the direct-acting carcinogens, as manifested by earlier morbidity and development of colon tumors (50% tumors within 30-35 wk), than were those of conventional rats (50% colon tumors within 48-50 wk). Germfree and conventional male rats were more susceptible to the carconogens than were their female germfree and conventional counterparts. Young (30 days old at the start of the experiment) germfree rats developed colon tumors more quickly (15-20 wk) than did older (60 days) germfree rats after intrarectal injections of MNNG. No colon tumors were observed in germfree and conventional rats after 75 weekly intrarectal injections with a buffer. Transplantation of an adenocarcinoma induced with MNU in a female rat to germfree and conventional rats showed that it was easily transplantable, required no immunosuppression, and had essentially the same morphologic characteristics as did the primary tumor.

Adenocarcinoma↗

Transparent plastic incubator for the anaerobic glove box.

An incubator designed for use inside an anaerobic glove box is described. The incubator is made of transparent plastic material, has sliding plastic doors, and can be made in various sizes from readily available materials.

Journal Article↗

Bacterial association in the gastrointestinal tract of beagle dogs.

Nine male beagle dogs, housed in either a conventional or locked environment for 2.5 years, were killed, and the bacterial flora present in various regions of each gastrointestinal tract was assessed by culture techniques, light microscopy, and scanning electron microscopy. All dogs possessed a complex microflora in their colons; in almost every dog anaerobes predominated. The highest number of bacteria cultured was 10(10)/g (dry weight) of tissue and contents; highest counts obtained with a Petroff-Hauser counting chamber were 10(10)/ml (wet weight). Although there was a consistency in the detectable genera, there were also noticeable differences in the flora of dogs housed under different environmental conditions. These differences included qualitative and quantitative changes in the flora as well as alterations in the distribution and localization of microorganisms along the gastrointestinal tract and in the crypts of Lieberkuhn. No bacterial layers were detected on the surfaces of stomach or proximal bowel in any of the dogs. Dogs housed in a conventional, open, environment had bacteria that occurred in layers on their ceca and colons and in their crypts of Lieberkuhn; however, dogs housed under "locked" environmental conditions did not possess them or had them less frequently. Dogs removed from the locked environment and kept (30 days) in conventional housing conditions were the only ones with detectable segmented filamentous microbes in their ilea. This study shows that the microbial flora does not simplify when dogs are housed in a locked environment. Indeed, it may increase in complexity and cause alterations in the bacterial flora that is associated closely with gastrointestinal epithelial cells and crypts of Lieberkuhn.

Aerobiosis↗

Nose, throat, and fecal flora of beagle dogs housed in "locked" or "open" environments.

The microbial flora of the nose, throat, and feces of male beagle dogs housed in a "locked environment" (i.e. confined to germfree-style isolators and supplied with sterile food, air, and water) or an open environment were assessed between 26 and 30 months into the study. Forty-five genera and 170 different species or types of microorganisms were cultured from the nose, throat, and feces of the beagles. Clostridia, eubacteria, corynebacteria, bacteroides, lactobacilli, and anaerobic, gram-positive cocci accounted for most of the microbial diversity in the flora. Some of the facultative anaerobes, especially streptococci and lactobacilli (in feces), occurred in numbers that were comparable to the most numerous anaerobic species. Confinement to the locked environment resulted in an increased diversity of microorganisms in the flora, but the total microbial counts did not increase to any great extent. Even with the increased diversity of bacteria in the flora of confined dogs, some bacteria seemed to favor certain areas of the gastrointestinal tract over others. The increased diversity of bacteria observed in these confined dogs may pose some infectious disease problems for other mammals (including humans) that may be confined to a locked, ultra-clean environment for a prolonged period of time.

Aerobiosis↗

New blood culture medium.

A growth medium with a specific oxidation-reduction potential containing peptone, dextrose, sodium succinate, sodium lactate, gelatin, sodium bicarbonate and blue tetrazolium, an indicator dye, in a tris(hydroxymethyl)aminomethane buffer was used to detect the presence of microorganisms in blood. The procedure involved the introduction of blood (and bacteria) into the growth medium with the dye in its colorless state. As the bacteria grew, they converted the dye to a visible blue color (formazan) with their reductases. The growth medium served as its own contamination control, since microbial growth and be detected by a color change before it was used for blood culture. The experiments described herein demonstrate that the composition of this medium (with the dye) provides a unique system that is able to make a reliable and rapid detection of both gram-positive and gram-negative microorganisms and yeasts (Candida albicans) commonly associated with bacteremia.

Bacteria↗

Bladder response to klebsiella infection: a scanning electron microscopy study.

The early response of rat bladder epithelium to Klebsiella pneumoniae was examined using scanning electron microscopy. Increased bacterial adherence with time after challenge paralleled the occurrence of strand formation and ulceration on the bladder epithelium. The early bladder response to the bacteria consisted of altered epithelial membrane structure, strand formation, and exfoliation of some epithelial cells. These observations indicate that K. pneumoniae causes alterations in the bladder epithelium which may trigger an intrinsic bladder defense mechanism consisting of strand entrapment of bacteria, epithelial cell exfoliation, and elimination of attached bacteria via voiding.

Animals↗

Pneumatosis cystoides intestinalis.

Pneumatosis cystoides intestinalis (PCI) is an uncommon disease of previously unknown etiology, characterized by the presence of gas-filled cysts in the walls of some portion of the gastrointestinal tract. This investigation showed that PCI was readily produced in the germfree rat by inoculating its peritoneal cavity with a pure culture of either C. perfringens or C. tertium. Similar inoculation of the germfree animal with any one of eight other clostridia species did not result in the formation of PCI. The bacterial theory for the formation of at least some cases of PCI is now established. This work suggests that part of the treatment of those fulminating diseases known to be frequently associated with PCI should be directed at controlling a possible clostridial infection.

Animals↗