PubMed Health⌕ Search

Biomedical subjects

E Segal

Publications and source records attributed to E Segal.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of adherence of Candida albicans to acrylic by a chitin derivative.

The purpose of this study was to assess the effect of a chitin derivative (CSE) on the adherence of Candida albicans to acrylic. Fungal adherence to acrylic dentures is considered an essential step in the development of denture stomatitis. Adherence of C. albicans to acrylic pieces (5 x 5mm) was assessed microscopically using a calibrated ocular objective and expressed as number of adherent yeasts/mm2 of acrylic. CSE was prepared from commercial chitin (crab shell) and from chitin isolated from C. albicans blastospores. The effect of both CSE types on the adherence of C. albicans to acrylic was examined in two experimental systems: CSE present during the adherence assay and acrylic pieces pretreated with CSE prior to the assay. Both CSE types exerted a significant inhibitory effect when tested in the two experimental systems. These findings are significant for possible prevention of denture stomatitis.

Acrylic Resins↗
PubMed1992

Cytotoxic activity of platinum (II) complexes with tri-n-butylphosphine. Crystal structure of the dinuclear hydrazine-bridged complex, cis,cis-[PtCl(PBu3n)2(mu-N2H4)PtCl(PBu3n) 2] (ClO4)2.2CHCl3.

A series of platinum(II) tri-n-butylphosphine complexes having the formulas cis-[PtCl2L2], NEt4[PtCl3L], [PtCl(en)L]Cl, [Pt(en)L2](ClO4)2, sym-trans-[Pt2Cl4L2], [Pt2Cl2L4](ClO4)2, trans,trans-[PtCl2L(mu-N2H4)PtCl2L] trans,trans-[PtCl2L(mu-en)PtCl2L], and cis,cis-[PtClL2(mu-N2H4)PtClL2](ClO4)2 (L = tri-n-butylphosphine; en = ethylenediamine) have been synthesized and their cytotoxic activity in vitro and in vivo has been studied. The solution behavior of the novel dinuclear diamine-bridged platinum(II) complexes has been investigated by means of UV and 31P NMR spectroscopy. For the ionic hydrazine compound cis,cis-[PtClL2(mu-N2H4)PtClL2](ClO4)2, an x-ray structure determination is reported. Crystal data: space group P2(1)/a, a = 17.803(1), b = 18.888(3), c = 12.506(3) A, beta = 107.97(2) degrees, Z = 2, R = 0.052, RW = 0.058. The platinum coordination is approximately square-planar, with the bond lengths Pt-Cl = 2.358(5), Pt-N = 2.15(1), Pt-P(trans to Cl) = 2.260(5), and Pt-P(trans to N) = 2.262(6) A. All investigated compounds were cytotoxic in vitro against L1210 cells and showed no cross-resistance to cisplatin. On the other hand, no antitumor activity was observed vs L1210 leucemia in DBA2 mice.

Animals↗
PubMed1992

Fatal systemic candidiasis of gastrointestinal origin: an experimental model in mice compromised by anti-cancer treatment.

An experimental model of fatal systemic candidiasis originating from the gastrointestinal (GI) tract of compromised mice is presented. ICR female mice were compromised by a single anti-cancer treatment: irradiation (4 or 6 Greys i.e. 400-600 rads), methotrexate (MTX) (3 mg per mouse, intraperitoneally) or 5-fluorouracil (5FU) (200 mg kg-1, intravenously). Three days later, compromised and non-treated control mice were exposed to Candida albicans administered orally. Morbidity and mortality due to candidiasis were monitored for 30 days post-candidal inoculation. Increased and longer GI colonization was noted among the MTX and 5FU treated mice, or 6 Greys irradiated mice (up to 92.3% for over 30 days in anti-cancer treated mice). The stomach was found to be the major part of the GI tract involved in fungal colonization. A significant number (53.8-83.3%) of the anti-cancer treated mice developed systemic candidiasis originating from the GI tract, which was fatal in 30-80% of the infected animals. In systemically infected animals, candidal antigen was demonstrated in the serum, and fungal abscesses containing C. albicans were observed in the liver, kidneys and spleen. C. albicans was isolated from the infected organs. The severity of the infection, as reflected by the number of fungi in visceral organs, and by mortality during the 30 days post-candidal inoculation, indicated differences in the course and nature of the infection among the three treatment groups (i.e. MTX, 5FU, 6 Greys).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Interferon and natural killer cell activity in patients with exanthem subitum.

Early immune response was studied by assessing interferon (IFN) and natural killer cell activity in 13 patients with exanthem subitum associated with human herpesvirus 6 infection during the acute and convalescent phases. Only IFN-alpha showed a significant increase in the plasma of patients during the acute febrile phase compared with the convalescent period. The inhibitory effect of IFN-alpha and IFN-beta on human herpesvirus 6 replication was demonstrated in vitro with cord blood mononuclear cells. Natural killer cell activity was also significantly augmented in the acute phase, especially in the exanthem period, rather than in the convalescent phase (P less than 0.01). These results suggest that the enhanced IFN-alpha response and natural killer cell activity in the acute early phase of the disease may play pivotal roles in the recovery from exanthem subitum.

Cytotoxicity, Immunologic↗
PubMed1991

[Surgery for thoraco-abdominal aortic aneurysm].

12 patients underwent resection of a thoraco-abdominal aortic aneurysm. There were 10 men and 2 women, ranging in age from 54-78 years (mean 65). Aortic arteriosclerosis was the primary etiology in 11, and Behcet's disease in the other 1. Most patients (7/12) presented with Type 3 aneurysm, extending from the distal descending thoracic aorta to the distal abdominal aorta; none had aortic dissection. 11 were operated on for symptoms related to the aneurysm: 3 of these had a contained rupture. The risk factors were chronic obstructive pulmonary disease in 10, hypertension (10), diffuse arteriosclerosis (8), ischemic heart disease (6), chronic renal failure (5) and cerebrovascular accident (1). The surgical technique in 11 was graft inclusion and visceral vessel reattachment. The main complication was acute renal failure, seen in 3 patients. None had spinal ischemia. Operative mortality was 33%. Of the 4 who died, 2 had myocardial infarction and 2 uncontrolled intraoperative bleeding. According to the literature the major complications are spinal cord ischemia and renal failure.

Acute Kidney Injury↗
PubMed1991

Adhesion of Candida albicans to epithelial cells effect of polyoxin D.

Data from our previous studies suggested that the fungal cell wall component, chitin, is involved in the adhesion of Candida albicans to mucosal surfaces. In the present study, we investigated the effect of polyoxin D, an inhibitor of chitin synthase, on the interaction of the fungus with epithelial cells. The effect of polyoxin D on Candida was evaluated in in vitro assays for its capacity to adhere to buccal epithelial cells (BEC), and by fluorescent-microscopy photometry and flow cytometry using cells stained with cellufluor (CF), a fluorochrome with affinity for chitin. C. albicans grown with and without polyoxin D was stained with CF and examined in a fluorescent microscope equipped with a photometer. Measurements of fluorescence revealed a wide range of intensity among C. albicans cells and a decreased intensity in polyoxin D treated cultures. Flow cytometry analyses of yeasts revealed 2 peaks of fluorescence intensity, and pointed to differences between polyoxin D treated and non-treated microorganisms. C. albicans stained with CF were separated into 2 subpopulations by flow cytometry according to fluorescence intensity. In vitro adhesion of each subpopulation to BEC was similar. Polyoxin D treated fungi showed significantly reduced adherence to BEC, as evaluated by a radioactivity assay with radiolabelled yeasts and by microscopic readings. The reduction in adhesion was Polyoxin D concentration dependent. These observations support our previous findings suggesting involvement of chitin in the attachment process of C. albicans (CBS562) to epithelial cells.

Antifungal Agents↗
PubMed1991

Herniated L4-L5 disc after placement of Harrington instrumentation for a fracture of the thoracolumbar spine.

The authors report a case in which L5 radiculopathy developed acutely after surgery for placement of Harrington rod instrumentation for an L1 body fracture. Computed tomographic myelography demonstrated a large L4-L5 herniated disc that had not been present in preoperative studies. An emergency laminectomy was performed, and a large, free, subligamentous disc fragment was removed. The patient subsequently regained L5 sensorimotor function. The postoperative development of lumbar radiculopathy is an uncommon complication of Harrington rod instrumentation that may result from several biomechanical features of the instrumentation. These injuries may not be detected by intraoperative monitoring of somatosensory evoked potentials, and therefore, the postoperative neurological examination assumes a crucial role in the early diagnosis of these lesions. As our case demonstrates, these radicular deficits may be reversible if their cause is promptly recognized and treated.

Aged↗
PubMed1990

Nuclear magnetic resonance and lipids of the plasma from patients with intracranial tumours.

The plasma of fifteen patients with malignant primary intracranial central nervous system (CNS) neoplasms was examined using proton nuclear magnetic resonance (NMR) and lipid level analysis. Twenty-three benign intracranial neoplasms and twelve non-CNS, non-malignancy patients served as control. At 300 MHz the NMR mean line width of plasma with malignant tumours was (+/- 2 SE) 37.2 +/- 3.0 Hz and for benign tumours 33.5 +/- 3.0 Hz (P = 0.09). The mean plasma triglyceride level for the malignancy patients was 100 +/- 25 mg/decilitre and 173 +/- 74 mg/decilitre for the patients with benign tumours (P = 0.07). The mean plasma cholesterol was 182 +/- 42 mg/decilitre for the malignancy patients and for the patients with benign tumours 241 +/- 29 mg/decilitre (P = 0.03). Unfortunately overlaps of the values of the different groups, in spite of statistically significant differences, detracts from the clinical usefulness of these criteria. Attempts to combine these values and correct for tumour volume, as calculated from computerized tomography, did not improve the differentiation between these two groups. Although it has been reported that plasma NMR and lipid levels can differentiate between malignant and benign tumours in general and in the central nervous system, these criteria are not adequately sensitive and specific to replace histology for the definite diagnosis of central nervous system tumours.

Biomarkers, Tumor↗
PubMed1990

Isolation of the Candida albicans histidinol dehydrogenase (HIS4) gene and characterization of a histidine auxotroph.

Genetic studies were done with Candida albicans CBS 562. Various auxotrophs were isolated following mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. SAG5 (his4C), a stable histidine auxotroph defective in histidinol dehydrogenase activity, was characterized and chosen for further molecular studies. Therefore, the C. albicans HIS4 gene was isolated. The gene was obtained from a genomic library of the wild-type strain, which was constructed in plasmid YEp24. The HIS4 gene was isolated by transformation of a Saccharomyces cerevisiae strain that carried a his4 mutation. The isolated C. albicans HIS4 gene complemented S. cerevisiae his4A, his4B, his4C, and his4ABC mutant strains, which indicates that the clone contains the entire HIS4 gene. The gene was isolated on plasmid pSTC7, whose physical map was constructed with BamHI, SalI, and EcoRV restriction endonucleases, locating the HIS4 gene on a 14-kilobase-pair DNA fragment. Hybridization experiments with HIS4 and C. albicans genomic DNA showed correspondence between the restriction patterns of the gene with that of the chromosomal DNA, indicating that the gene originates from C. albicans and appears in a single copy. Chromosomes of C. albicans CBS562 and four other strains were resolved by orthogonal-field alteration gel electrophoresis. The electrokaryotyping results showed heterogeneity in chromosomal sizes. The electrokaryotyping of CBS 562 showed a resolution of six chromosomal bands, three of which seemed to be doublets. The C. albicans HIS4 gene was located on the largest resolvable chromosome in all of the strains.

Alcohol Oxidoreductases↗
PubMed1990

Comparison of Candida albicans adherence to human corneocytes from various populations.

Epidemiological data indicate that patients suffering from diabetes, hypothyroidism, obesity, or following prolonged treatment with antibiotics, corticosteroids or oral contraceptives, have an increased tendency to develop cutaneous candidiasis. Since it is generally believed that attachment of microorganisms to host cells is an initial step in the evolution of infection, the aim of the present study was to investigate whether cells from susceptible individuals have increased capacity to bind the fungus. Corneocytes collected from the forearms of individuals of these susceptible groups were exposed in vitro to Candida albicans and adhesion to the cells was evaluated in comparison with adherence to cells from a non-susceptible population. Adherence in vitro was assayed microscopically and evaluated quantitatively by two parameters: 1) percentage of adherence - number of corneocytes with adhering yeasts on their surface, and 2) the total number of adhered yeasts. Results of the study revealed that the mean percentage of adherence and the mean total number of yeasts adhering to cells from individuals of the susceptible populations was twice as high as values in a healthy population. Statistical analysis of the data by Student's t-test indicated that the difference was significant (p less than 0.001).

Adult↗
PubMed1990

Interaction of Candida albicans with murine gastrointestinal mucosa from methotrexate and 5-fluorouracil treated animals: in vitro adhesion and prevention.

The aim of the present study was to investigate whether the cytotoxic anti-cancer drugs methotrexate (MTX) or 5-fluorouracil (5FU), which affect the gastrointestinal (GI) mucosa, would also affect the ability of the damaged mucosa to bind the GI commensal yeast Candida albicans. ICR conventional female mice were treated with intraperitoneal (IP) MTX (3 mg per mouse, or intravenous (IV) 5FU (200 mg kg-1 body weight). On various days post-treatment, the small intestine was removed, tissue disks prepared and exposed for 2 h to radiolabeled C. albicans. The percent adherence of the fungus to the mucosa was assayed by determining the counts per minute (c.p.m.). An increase in the in vitro adherence of C. albicans to murine GI mucosa was found posttreatment with MTX or 5FU. The maximal increase (net increase of 40-50%) was observed on days 3-4 post-treatment with MTX or 5FU, concurrently with the maximal decrease in the total number of white blood cells (WBC) and loss in spleen weight of the treated animals (indicators of cytotoxicity of these drugs). In addition, experiments to block Candida adherence with chitin soluble extract (CSE), an inhibitor used in previous studies, were also carried out. CSE inhibited the adherence of C. albicans to the damaged GI mucosa, as well as to the GI mucosa from normal untreated mice, by up to 64% approximately. Based on these results and on findings from our previous study investigating the adherence of C. albicans to GI mucosa from irradiated mice, it can be concluded that increased adherence of C. albicans to the GI mucosa may occur in patients post-anti-cancer therapy (irradiation, or chemotherapy). This observation may partially explain the high tendency of these debilitated patients to develop systemic candidosis. Further experiments to study adherence of C. albicans to gut mucosa in vivo and eventually to inhibit this adherence with CSE are currently in progress in our laboratory.

Animals↗
PubMed1989

Vaccines for the management of dermatophyte and superficial yeast infections.

Efforts have been made to induce protective immunity to the infections caused by dermatophytes, Candida, and Malassezia. The following conclusions can be drawn from the studies reviewed. 1. The research directed toward the management of dermatophyte infections by vaccination have yielded a promising vaccine for prevention of T. verrucosum infections in cattle. 2. A number of investigators have attempted, by various methods and with different immunogenic preparations, to prevent superficial mucocutaneous candidiasis. The results of those investigations do not indicate that a vaccine for prophylaxis of this disease is forthcoming. 3. No vaccination attempts for prevention of pityriasis versicolor have been described.

Animals↗
PubMed1989

The effect of tidal volume and intravascular volume state on systolic pressure variation in ventilated dogs.

Both tidal volume and effective blood volume may affect the variation in the arterial pressure waveform during mechanical ventilation. The systolic pressure variation (SPV), which is the difference between the maximal and minimal systolic pressure values following one positive pressure breath was analyzed in 10 anesthetized and ventilated dogs, during ventilation with tidal volumes of 15 and 25 ml/kg. The dogs were studied during normovolemia, hypovolemia (after bleeding of 30% of estimated blood volume) and hypervolemia (after retransfusion of shed blood with additional 50 ml/kg of plasma expander). The SPV reflected hemodynamic changes and was maximal during hypovolemia and minimal during hypervolemia. Unlike all other hemodynamic parameters it was also affected by the tidal volume and significantly increased at higher tidal volumes during each volume state. We conclude that the SPV and its components are useful parameters in evaluating the intravascular volume state. They also reflect the magnitude of the tidal volume employed.

Animals↗