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Biomedical subjects

H Ben-Hur

Publications and source records attributed to H Ben-Hur.

At least 91 records · Page 5Linked to original sources
PubMed1986

Selective labeling of functional groups on membrane proteins or glycoproteins using reactive biotin derivatives and 125I-streptavidin.

Amino groups, sulfhydryl groups or oxidation-induced aldehydes on erythrocyte membrane proteins and/or glycoproteins, were reacted with biotinyl N-hydroxysuccinimide ester (BNHS), 3-(N-maleimido-propionyl) biocytin (MPB) or biocytin hydrazide (BCHZ), respectively. The detergent-lysed biotinylated samples were subjected to SDS-polyacrylamide gel electrophoresis, and the proteins were transferred onto nitrocellulose membranes. The blot was then incubated with a solution containing 125I-streptavidin, and processed for autoradiography. The advantages of this approach over previously reported procedures for labeling the three functional groups include the following: extremely high sensitivity; short exposure times of autoradiograms and relatively low levels of radioactivity; single-step radiolabeling procedures subsequent to processing and handling of gels and no background labeling in control samples.

Bacterial Proteins↗
PubMed1986

A sensitive enzyme assay for biotin, avidin, and streptavidin.

Reciprocal enzyme assays are described for the vitamin biotin and for the biotin-binding proteins avidin and streptavidin. The assays are based on the following steps: (a) biotinylated bovine serum albumin is adsorbed onto microtiter plates; (b) streptavidin (or avidin) is bound to the biotin-coated plates; (c) biotinylated enzyme (in this case alkaline phosphatase) is then interacted with the free biotin-binding sites on the immobilized protein. For biotin assay, competition between the free vitamin and the biotinylated enzyme is carried out between steps (b) and (c). The method takes advantage of the four biotin-binding sites which characterize both avidin and streptavidin. The method is extremely versatile and accurate over a concentration range exceeding three orders of magnitude. The lower limits of detection are approximately 2 pg/ml (0.2 pg/sample) for biotin and less than 100 ng/ml (10 ng/sample) for either avidin or streptavidin.

Alkaline Phosphatase↗
PubMed1986

An improved method for the single-step purification of streptavidin.

A new method for the preparation of a more efficient, stable iminobiotin-containing resin for the isolation of streptavidin was developed. CL-Sepharose was activated with p-nitrophenyl chloroformate, and the resultant carbonate derivative was reacted with diaminohexane. Subsequent reaction of the amino-containing resin with iminobiotin-N-hydroxysuccinimide ester (in an organic solvent) yielded the stable affinity resin. The capacity of this resin for either avidin or streptavidin was 12 mg per ml resin, and streptavidin could be purified in one step directly from the culture broth of Streptomyces avidinii. The biotin-binding protein isolated in this manner exhibited a major band at about 75 kDa and a minor band at about 150 kDa. Under denaturing conditions, a spectrum of subunit molecular weights ranging between 15 and 19 kDa was detected, the distribution of which depended upon the specific preparation.

Bacterial Proteins↗
PubMed1986

Ovarian carcinoma masquerading as ovarian hyperstimulation syndrome.

Two patients receiving ovulation-inducing drugs were found to have ovarian carcinoma. Since patients receiving such medication are prone to develop enlarged ovaries with or without the fully developed hyperstimulation syndrome, the diagnosis of ovarian tumors in such patients may be delayed or missed. It is therefore being suggested that an ovarian enlargement persisting for more than 4 weeks, or the finding of ovarian solid masses by sonography in patients receiving ovulation-inducing drugs, should lead to a thorough work-up for neoplasia, sometimes including even laparotomy.

Adult↗
PubMed1983

Non-aggressive management of post-date pregnancies.

A non-aggressive approach to the management of post-date pregnancies was tested in a clinical trial involving 156 patients who had reached 294 days of amenorrhea and had a pelvic score of 4 or less. Dates had been established with certainty in each case. In half of the patients (the study group) no time limit was imposed on the pregnancy, but the women were checked at frequent intervals for any increase in pelvic score and for changes in any of the following: fetal movement count recorded daily by the mother, an oxytocin challenge test, and amnioscopy. The pregnancy ended either through spontaneous contractions or through surgical induction carried out because of a change in any one of the parameters or an increase above 4 in the pelvic score. In the 78 control patients labor was induced surgically on day 294, even if the pelvic score was low. In the study group, labor started spontaneously in 52 patients; labor was induced in 17 women after they showed an elevated pelvic score, in 7 because of a pathologic parameter and in one because a mild pre-eclampsia developed. There were 7 cesarean sections in the study group compared with 16 in the control group (P less than 0.05). The average duration of labor was 6.7 h in the study group, compared with 9.4 h in the control (P less than 0.01). There was no significant difference between the two groups with regard to meconium staining during labor, pathologic fetal heart rate, or the 5 min Apgar score. In the study group there was one neonatal death as a result of severe congenital heart disease, and in the control group one infant died due to asphyxia. It is concluded that conservative management of prolonged pregnancies, with close supervision, gives better results than routine induction of labor at 42 wk. The importance of the pelvic score as an indication for induction is stressed. A protocol has been developed which can be used in cases of uncertain dates as well.

Clinical Trials as Topic↗
PubMed1982

The clinical significance of rheometric measurement of cervical mucus properties.

Rheometric properties of cervical mucus were studied with the Ovutimer in 26 women. 14 women had regular menstrual cycles, 12 had menstrual irregularities and received treatment to induce ovulation. In 21 women (80.7%) a significant correlation was found between the ovulation time as established by the luteinizing hormone surge, and ovulation time as established by the Ovutimer test. The instrument was found satisfactorily accurate in establishing the day of ovulation in almost all cases.

Anovulation↗
PubMed1982

The beneficial effect of vacuum extraction of the fetus.

The vacuum extractor (VE) was applied electively after approximately 25 min of expulsion in 25 normal primiparae. Twenty-five identical parturients with spontaneous deliveries served as controls. The fetal scalp pH was measured at the beginning of the 2nd stage, and again in the cord blood of all newborns. Cardiac monitoring by scalp electrode was done for all fetuses throughout labor. The mean pH of the first blood sample was almost identical in the two groups, while the mean decrease in pH in the VE group was 0.077, against a mean change of 0.106 in the controls (p less than 0.05). In the FHR graph the total area of deceleration, and separately in the controls (p less than 0.05). In the FHR graph the total area of deceleration, and separately the up to 30 beats/min (area A) and of more than 30 beats/min (area B) were calculated. The mean total area of deceleration in the VE group was 14.76 cm2vis-à-vis 17.56 cm2 in the controls. Areas A and B were also smaller in the study group, but these differences were not statistically significant. The mean total deceleration time in the VE fetuses was 22.8 min, and 37.75 min in the controls (p less than 0.001). It is concluded that the application of the VE during the second stage lessens fetal depression, when compared with spontaneous delivery.

Extraction, Obstetrical↗
PubMedDate not supplied

Clinical aspects of ovarian tumors of low malignant potential.

A review of 21 cases of ovarian tumors of low-malignant potential diagnosed in our department over a period of 13 years was undertaken. Ninety percent of the patients presented with stage I disease. The average age at diagnosis (45 years) was younger than commonly found in patients with invasive epithelial cancer. Three patients received postoperative chemotherapy, and all of those were evaluated by second-look laparotomy. One of our patients with stage Ic serous tumor recurred with lung metastases. In two other patients with mucinous tumors, mucocele of the appendix was found. The five year survival in this series was 100%. Our study emphasizes the need for a prospective study to evaluate the value of adjuvant therapy in the various stages of these ovarian neoplasms.

Adenocarcinoma, Mucinous↗
PubMedDate not supplied

Pathology of lymphoid organs in low-birth-weight human fetuses subjected to antigen-induced influences: a morphological and morphometric study.

To evaluate the pathology of lymphoid organs in low-birth-weight (LBW) human fetuses obtained after premature birth, morphological and morphometric features were studied. The ages of fetuses ranged from 22 to 32 weeks and their weights from 400 to 1180 g. In fetuses at 22-23 weeks without antigenic effects, the lymphoid organs were seen to be well developed and their differentiation was similar to that of full-term fetuses. In older unaffected fetuses (up to 32 weeks), a significant increase in size of the lymphoid organs and a rise in the rate of the differentiation of lymphoid cells were observed. Fetuses exposed to antigen-related diseases underwent morphological changes in lymphoid organs presumably as a consequence of the primary fetal immune reaction. These changes were characterized by a high increase in the number of lymphoblasts and partly of macrophages in the spleen and lymph nodes. Reactive centers in spleen follicles and in lymph nodes, and plasmocytes in all the lymphoid organs, were absent. The main reaction to severe antigenic influences was decompensation of the lymphoid organs manifested morphologically by their devastation as a result of a decrease in the number of small lymphocytes and, in severe cases, of lymphoblasts and macrophages. Exposure of fetuses to antigen-related diseases thus appears to cause marked changes in the normal ontogenesis of lymphoid organs.

Antigens↗
PubMedDate not supplied

Melatonin and colon carcinogenesis. IV. Effect of melatonin on proliferative activity and expression of apoptosis-related proteins in the spleen of rats exposed to 1,2-dimethylhydrazine.

The suppression of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis by melatonin was previously demonstrated. The objective of the present work was to evaluate histologically and immunohistochemically the splenic immune response to the induced cancer and to melatonin. Spleens from rats, either untreated, injected with DMH, fed with melatonin or treated with both carcinogen and melatonin, were studied. The exposure to the carcinogen and the consequential carcinogenesis resulted in splenic changes that reflected the insufficiency of the immune response, as manifested in significant reduction of the white pulp and the simultaneous expansion of the red pulp. The effects of melatonin on most splenic components were inverse to those of DMH. The anti-carcinogenic properties of melatonin were evidenced from the reversal of the inhibitory effects of DMH, especially when the densities of lymphocytes in different parts of the spleen were compared. The combined treatment of the rats with DMH and melatonin resulted in the expansion of the splenic zones by 106% to 125%, compared to those from DMH-treated rats, and the numbers of CD8+ lymphocytes and Fas-positive cells increased sharply. Therefore we conclude that anti-carcinogenic effects of melatonin are related to activation of several elements of the host's lymphatic system.

1,2-Dimethylhydrazine↗
PubMedDate not supplied

Comparative effects of dimethylbenz(a)anthacene and a 15% olive-oil diet on cellular components and expression of apoptosis-related proteins in the spleen and mammary gland tumors of rats.

We compared effects of a high fat diet and a carcinogen on cellular elements of the spleen and mammary gland tumors in rats. Animals were fed a 15% olive-oil diet and a group of them were exposed to a carcinogen, dimethylbenz(a)anthacene (DMBA), in two doses of 10 mg/rat. Results of the experiments were evaluated after 4 months. We studied changes in the areas of different zones of the spleen related to production of B and T lymphocytes and also the number of cells in the spleen and tumors with positive reaction to receptors related to manifestation of apoptosis (FasL and p53) and receptors related to inhibition of apoptosis (bcl-2). In the spleen, dietary fats as well as DMBA alone decreased the zones related to production of B lymphocytes and increased the number of T lymphocytes. The combined effect of a carcinogen and a high fat diet manifested in an increase in the number of lymphoid cells and macrophages. In tumors from rats fed a low-fat diet, an extremely high number of lymphoid cells was seen in the border of tumors with T cell killers as a main component of these infiltrates. In tumors from rats fed a 15% olive-oil diet, the main component of the infiltrates were macrophages. High levels of p53+ and bcl-2+ cells were found in the spleen of rats exposed to a carcinogen. The combined effect of a carcinogen and the 15% olive-oil diet inhibited production of FasL and p53 receptors and stimulated synthesis of bcl-2 protein. In tumors, a carcinogen alone stimulated the high expression of FasL and p53 proteins, but in combination with the 15% olive-oil diet synthesis of these receptors decreased while production of bcl-2 protein increased sharply. This observation may serve as an additional proof of tumor-promoter effects of a high fat diet.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

Effect of giant hepatomas on lymphocyte production and secretion of apoptosis-related proteins in the rat spleen.

The effect of extremely large hepatomas on splenic lymphoid elements and apoptosis-related proteins in rats were studied. Hepatoma cells were inoculated subcutaneously into 6-week-old rats, and 4 months later the quantities of T and B cells, macrophages, and cells positive for Fas, Fas ligand (FasL) and interleukin-2 (IL-2) were immunohistochemically evaluated in spleens. Grafting of hepatoma cells caused hyperplasia of the spleen and development of giant tumors that could reach one-third of the rat's body weight. A 7-fold increase in the weight of the spleen was mainly due to proliferation of B lymphocytes and macrophages in the red pulp, while the relative quantity of CD4+ and CD8+ T cells decreased. Extremely small amount of Fas+ and FasL+ lymphocytes were present in the marginal zone, the follicles, red pulp, and occasionally in the PALS. All the splenic zones were abundant with IL-2+ cells, while macrophages and siderophages were present mainly in the red pulp and in the marginal zone of the white pulp. We suggest that all these changes are compensatory processes of the host's lymphatic system.

Animals↗
PubMedDate not supplied

Transplacental effect of a 15% olive-oil diet on functional activity of immune components in the spleen and colon tumors of rat offspring.

We studied whether feeding pregnant female rats a 15% olive-oil diet affects the activity of lymph cells in the spleen and tumors in offspring with chemically-induced colon tumors. Rat mothers were fed either a 7% corn-oil or a 15% olive-oil diet. Five-week-old male offspring were divided into 3 groups. A control group was fed the 7% corn-oil diet similar to their mothers. The experimental group I was fed the 7% corn-oil diet whereas their mothers were fed the 15% olive-oil diet. The experimental group II was fed the same 15% olive-oil diet as their mothers. Experimental rats were injected weekly for 8 weeks with the carcinogen, 1,2-dimethylhydrazine (DMH), 20 mg/kg b.w. Results of experiments were studied 6 months later. The area of zones in the spleen responsible for producing B and T lymphocytes were measured and the number of cells counted. The activity of lymphoid elements of the spleen and of tumors were studied using immunohistochemical methods for evaluating the synthesis of CD8(+) lymphocytes and proliferative activity of lymphocytes in spleens and tumors. Feeding pregnant or lactating mothers with the 15% olive-oil diet had no marked tumor-protective effect on chemically-induced colon cancer in offspring. Diet-dependent changes were found at the cellular level. In the spleen of control offspring, the presence of a tumor was accompanied by an increase in the number of Ki-67(+) cells and CD8(+) lymphocytes in the red pulp. In experimental group I, DMH significantly increased the total cell number and the number of CD8(+) lymphocytes in the red pulp of the spleen in both tumor-bearing and tumor-free rats. In experimental group II, the total number of lymph cells and the number of CD8(+) lymphocytes increased compared to offspring fed a control diet. Tumor formation activated the proliferative activity of lymph elements. The total number of cells in infiltrates of the colon mucosa decreased in tumor-bearing rats compared to tumor-free counterparts, and this was seen in all three dietary groups of rats. In tumors from offspring of experimental group II, only the number of CD8(+) lymphocytes increased compared to those in offspring of experimental group I. The findings indicate that feeding mothers the 15% olive-oil diet had a cancer-inhibiting role in offspring, predominantly changes at the cellular level.

1,2-Dimethylhydrazine↗
PubMedDate not supplied

Effects of a 15% orange-pulp diet on tumorigenesis and immune response in rats with colon tumors.

This study evaluated whether the feeding of rats with a 15% orange-pulp diet affects the lymphatic system and the tumorigenic response in rats exposed to a high dose of carcinogen. Five-week-old Sprague Dawley rats were divided into 2 groups fed a control chow diet or the same diet with 15% orange pulp. All rats were injected with 1,2-dimethylhydrazine (DMH) (20 mg/kg) weekly for 6 weeks. At 8 months, tumors, spleens and descending colon were taken from each group for analyses. Feeding rats the 15% orange-pulp diet did not reduce the tumor number but modified the number of adenocarcinomas found in the orange-pulp group compared to controls: 66.7% vs. 93.7%. The number of endophytic tumors was also significantly lower in the experimental group: 6.3% vs. 32.3% in controls. DMH affected the size of the splenic structures. The size of follicles and germinal centers decreased significantly in tumor-bearing rats compared to tumor-free rats. This effect was changed in rats fed the orange-pulp diet. In tumor-bearing rats from this group, only the area of the marginal zone decreased and the red pulp increased compared to tumor-free rats. The size of germinal centers significantly increased compared to tumor-bearing rats in controls. The total number of lymphoid cells decreased in germinal centers of spleens obtained from control tumor-bearing rats compared to tumor-free rats. DMH alone significantly increased the total number of cells in the colon mucosa of the rats fed the control diet. In tumor-bearing rats exposed to the carcinogen and fed the 15% orange-pulp diet, the total number of cells and the number of Ki-67+ cells increased in the depth of tumors whereas the number of CD8+ T cells increased in the colon mucosa, at the border of tumors and its depth. The caspase-3 protein a cysteine protease was elevated in tumors from rats fed the orange-pulp diet. Although the 15% orange-pulp diet did not change the number of tumors in the tumor-bearing rats, feeding rats orange pulp significantly decreased the number of endophytic tumors and increased the number of exophytic tumors. Increased activity of T cell killers in tumors and higher level of proteins involved with apoptosis following consumption of the orange pulp indicate a clear tumor suppressor effect of these dietary fibers.

Adenocarcinoma↗
PubMedDate not supplied

Mammary tumors in splenectomized rats.

The objective of this study was to examine how splenectomy affects the immune response, particularly T cells, in chemically-induced mammary tumors. Female rats were splenectomized and then exposed to 9,10-dimethyl-1,2-benz(a)anthracene (DMBA) to induce mammary tumors. Splenectomy significantly decreased the rate of tumor appearance and their malignant transformation. The tumor latency period in splenectomized rats was 12.0+/-0.9 weeks compared to 9.7+/-0.5 wk in intact controls, and malignancy appeared in 45% of splenectomized rats, compared to 70% in controls. By the end of the experiment, the total number of tumors and their size were similar in both groups. Blood CD4+ and CD8+ T cell concentrations were similar in tumor-bearing and tumor-free splenectomized animals, but in both groups CD4- and CD8- lymphocytes decreased sharply compared to control animals. In tumor-bearing rats, splenectomy also resulted in significantly more circulating natural killer cells. The spleens of tumor-bearing control rats had significantly fewer CD4+ and CD8+ lymphocytes and more CD4- and CD8- lymphocytes and natural killer cells than did their blood. In conclusion, splenectomy inhibits the early stages of tumorigenesis and reduces the rate of malignant transformation of benign tumors, but does not prevent the progress of carcinogenesis. Differences between splenectomized (operated) and intact rats to the effect of DMBA can be explained by an increase in non-specific resistance of splenectomized rats as a result of operation.

9,10-Dimethyl-1,2-benzanthracene↗