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At least 847 records · Page 47Linked to original sources
PubMed1983

Effects of surgical lubricants on semen analysis.

The effects of a number of commercially available surgical lubricants on the motility of spermatozoa with time, have been examined with the aim of recommending a non-toxic, water soluble aid which was not visibly detrimental to spermatozoa following collection of semen for routine analysis. The results have shown that motility is impaired at concentrations above 5%, but that below this level of contamination, spermatozoal motility, and progression, as objectively determined by multiple exposure photography, was unaffected. For various practical reasons, and because it is well known, K-Y Jelly, packaged as a single sachet, is probably the lubricant of choice.

Dose-Response Relationship, Drug↗
PubMed1984

Colony-forming ability in calcium-poor medium in vitro and tumorigenicity in vivo not coupled in clones of transformed rat hepatic epithelial cells.

The ability of eukaryotic cells in culture to proliferate in calcium-poor medium has been found to characterize populations of transformed cells, but the relationship between this phenotypic property and tumorigenicity at the cellular level is unclear. Thus, we have isolated 14 clonal subpopulations, based on their ability to colonize in calcium-poor medium, from a parental tumorigenic rat hepatic epithelial cell line which was transformed by multiple exposures to N-methyl-N'-nitro-N-nitrosoguanidine. These clonal subpopulations of cells were tested for their ability to grow in soft agar, to express gamma-glutamyl transpeptidase activity, and to form tumors upon back-transplantation into isogeneic newborn rats. The results indicated that clonal subpopulations of cells selected by their ability to grow in calcium-poor medium were phenotypically heterogeneous for gamma-glutamyl transpeptidase activity and anchorage-independent growth, and, more importantly, they were not more tumorigenic than the phenotypically heterogeneous parental cell line. This observation suggests that the capability of cultured hepatic epithelial cells to grow in calcium-poor medium is not tightly coupled to the tumorigenic phenotype.

Animals↗
PubMed1982

Hydroa vacciniforme: diagnosis and therapy.

Hydroa vacciniforme is a rare, chronic photodermatosis with onset in childhood. Multiple exposures to UV-A reproduced the symptoms and the vesicular and scarring lesions typical of the sun-induced disease in our patient. Treatment with hydroxychloroquine sulfate, but not indomethacin, reduced the photosensitivity both to sunlight and to artificial UV-A light. Serum complement levels were low while the disease was active and returned to normal after treatment of the patient with hydroxychloroquine.

Adolescent↗
PubMed1981

Autosomal translocation in an apparently normospermic male as a cause of habitual abortion.

A 22;22 Robertsonian translocation was diagnosed in a husband whose wife had had six consecutive early spontaneous abortions and no normal progeny. With the new multiple-exposure photography (MEP) technique, an accurate, objective and documentary sperm analysis was performed. No abnormality of the essentially defective, genetically unbalanced sperms could be detected in regard to sperm count, motility, velocity and morphology. The only similar translocation previously reported in a male was associated with azoospermia. Recent literature correlating chromosomal aberrations and reproductive failure in the male is discussed in relation to the reported case. The importance of including the male partner in the cytogenetic investigation of couples with habitual abortion is stressed.

Abortion, Habitual↗
PubMed1993

Effect of nickel sulfate alone and with ultraviolet light on micronuclei frequency in cultured human lymphocytes.

Comutagenic or cocarcinogenic activities have been reported between nickel compounds and UV light. The presence of micronuclei in a binucleated lymphocyte is regarded as an alternative to classical cytogenic methods for monitoring chromosomal damage. The present study aimed to detect this comutagenicity as regards micronuclei induction. Human peripheral lymphocytes were treated with different concentrations of nickel sulfate and/or with UV light at 200 and 1000 ergs/mm2. Cells have been cultured and 100 binucleated cells were counted and the micronuclei frequency recorded. The observed values for all concentrations of nickel sulfate combined with UV were less than expected for an additive response of two agents computed as the combined increase over the values of the control for the metal and UV alone. Caution is advised when interpreting cytogenic values in multiple exposures.

Adult↗
PubMed1995

Calcitonin gene-related peptide release in endotoxicosis may be mediated by prostaglandins.

Three cyclo-oxygenase inhibitors (ibuprofen, indomethacin, and high dose aspirin) and two inhibitors of thromboxane biosynthesis (imidazole and low dose aspirin) were used to evaluate the role of prostaglandins and thromboxane in the release of calcitonin gene-related peptide (CGRP) during endotoxicosis. Endotoxin (lipopolysaccharide B from Salmonella Enteritidis, 5 mg/kg, intravenously) was administered to rats lightly anesthetized with ether during injection. After 3 h, endotoxin significantly elevated plasma CGRP levels by 3-fold. Ibuprofen (50 mg/kg, subcutaneously), indomethacin (10 mg/kg, subcutaneously) and high dose aspirin (100 mg/kg, intraperitoneally (i.p.)), but not imidazole (30 mg/kg, i.p.) or low dose aspirin (15 mg/kg, i.p.), significantly blocked endotoxin-induced CGRP elevations, suggesting that a prostaglandin, but not thromboxane, served as a mediator of CGRP release during endotoxicosis. Because endotoxin-induced production of prostaglandins is greatly diminished in endotoxin-tolerant rats (following multiple exposures to low dose endotoxin), we tested whether endotoxin-induced CGRP release also becomes diminished in tolerant rats. Accumulation of plasma CGRP was greatly diminished in endotoxin-tolerant rats exposed to endotoxin (5 mg/kg, intravenously), consistent with a mediator role for prostaglandins in the CGRP release during endotoxicosis.

Animals↗
PubMed1978

Distribution of alpha-fetoprotein- and albumin-containing cells in the livers of Fischer rats fed four cycles of N-2-fluorenylacetamide.

Immunofluorescent localization of alpha-fetoprotein (AFP)- and albumin-containing cells was determined in the livers of Fischer rats fed 0.05% N-2-acetylfluorenamide for four 2-weeks-on, 1-week-off cycles. After this exposure multiple changes in the liver include over 1000 neoplastic nodules/liver, as well as extensive production of so-called oval cells and focal zones of atypical hepatocellular hyperplasia. Approximately 1% of the oval cells contain AFP, and about half of the zones of atypical hyperplasia include cells that contain AFP, but none of the neoplastic nodules or normal hepatocytes have any AFP-containing cells. Since up to 60% of the hepatocellular carcinomas developing from this regimen will predictably produce AFP, it is tentatively concluded that hepatocellular carcinoma may arise not only from "premalignant" neoplastic nodules but also from oval cells or the atpyical differentiation of hepatocytes.

2-Acetylaminofluorene↗
PubMed1993

Progress towards a vaccine against Theileria parva: relevance for heartwater research.

Such progress has been made in the last decade in the characterization of bovine immunity to Theileria parva. The evidence is overwhelming that cattle that become immune through infection can clear subsequent challenge infections by deploying parasite-specific cytotoxic T lymphocytes (CTL). Furthermore, high titres of neutralising antibodies are generated against the sporozoite surface after multiple exposure to the parasite, and these can neutralise infection in vitro. Although unlikely to be of relevance under natural circumstances, the latter observation has been exploited to generate a promising candidate neutralising vaccine based on a recombinant form of the major surface antigen of the T. parva sporozoites. Efforts are under way to identify the target antigen(s) of T. parva-specific CTL, and when this has been achieved, an improved vaccine targeted on both infective and pathogenic stages of the parasite will be within reach. The elucidation of the basis of immunity of ruminants to Cowdria ruminantium, the causal agent of heartwater, is at a comparatively early stage. However, many of the principles and techniques that have led to the current understanding of the immunology of T. parva are already being applied to heartwater, and these should enable rapid progress to be made in the development of a vaccine against C. ruminantium.

Animals↗
PubMed1993

[Influence of selenium-enriched malt on the elevated cGMP concentrations induced by carcinogen].

Rats were fed with selenium-enriched malt containing 1 ppm selenium. As a parameter, cyclic guanosine-3'5'-monophosphate (cGMP) was measured by RIA in the rats following treatment with AFB1. The results demonstrated that the diet containing high selenium inhibited the elevation of cGMP levels in the liver induced by multiple exposures to AFB1 (250 micrograms/kg, 10 times/2 wks), (P < 0.05). Administration of a large single dose of AFB1 (1 mg/kg i.p.) reduced the liver cGMP contents which might be due to injury to the liver. Selenium-enriched diet could prevent this from happening. In high cancer risk areas: the cGMP level in urine of population with higher selenium concentration were lower than that of population with low selenium concentration. A supplementation of 300 micrograms selenium in the form of selenium-enriched malt cakes daily to the subjects with low selenium concentration in blood for one year, the urinary cGMP excretion was significantly decreased from 0.62 mumol/g to 0.49 mumol/g creatinine (P < 0.05). These findings suggest that diet containing high selenium has a protective effect and may play a potential role in cancer chemoprevention.

Aflatoxin B1↗
PubMed1993

Nonradioactive gel mobility shift assay using chemiluminescent detection.

A nonradioactive gel mobility shift assay using chemiluminescent detection following semidry transfer to nylon membranes is described. The procedure utilizes digoxigenin-labeled oligonucleotides in conjunction with anti-digoxigenin antibody Fab fragments coupled to alkaline phosphatase. Detection of alkaline phosphatase is by autoradiography of the chemiluminescence produced during enzymatic dephosphorylation of a dioxetane substrate. This method offers similar sensitivity to radioactive methods while having the advantages of multiple exposures, faster processing, stability of labeled oligonucleotides and safety associated with nonradioactive methods of detection.

DNA-Binding Proteins↗
PubMed1977

Surgical repositioning of the medial collateral ligament. An anatomical and mechanical analysis.

Analytical techniques using multiple-exposure roentgenograms were employed to investigate surgical repositioning of either the femoral or the tibial attachment of the medial collateral ligament. The motion of the femoral attachment of the ligament with respect to the tibial attachment was used to compute the changes in length of the borders of the ligament for normal knees and for knees with repositioned attachments. The results support the conclusion that when advancement of the medial collateral ligament is utilized in the treatment of medial instability, optimization is accomplished by distal and anterior advancement with the knee in 30 degrees of flexion. Femoral displacement (proximal realignment) or tibial displacement at knee-flexion angles greater than 45 degrees is not recommended.

Biomechanical Phenomena↗
PubMedDate not supplied

[The biological effects of irradiation and hyperthermia].

Experimental data on the effects of radiation and hyperthermia on Chinchilla rabbits are presented. Multiple exposure to heat (40 degrees C, 20 min) between two radiation fractions was shown to influence favourably such haematological indexes as leukocyte and erythrocyte number and life-span of irradiated animals. Extra (to irradiation + heat) hyperthermia applied immediately before irradiation increased the radiation effect.

Animals↗
PubMed1993

A cell-kinetics model for radiation-induced myelopoiesis.

A mathematical model of time-dependent cellular damage, repair, killing and repopulation of bone marrow following treatments with ionizing radiations is described. Effects from variable dose rates, multiple exposures, different radiation sources and arbitrary intervals between treatments can be modeled by ordinary differential equations. Of several unique features, the most unusual is that rate constants for injury, repair, killing and proliferation of cells are evaluated by likelihood analysis of animal mortality data. Results indicate that a relatively radioresistant pool of bone marrow cells mediates the proliferation of the hematopoietic stem cells. Applications include modeling of 1) myelopoietic integrity as a function of time and dose rate, 2) the whole-body survival curve (at any point in the treatment protocol) for cells critical to myelopoiesis, 3) a prompt dose equivalence from any completed portion of a therapeutic schedule and 4) potential gain from schedule changes during the course of the treatment.

Animals↗
PubMed1995

Surface and internal absorbed doses in mandibular and maxillary occlusal radiography.

The objective of this study was to determine the absorbed radiation doses to various structures within the head and neck as a result of routine mandibular and maxillary occlusal radiography. Five projections were investigated: the anterior mandibular; true mandibular; anterior maxillary; lateral maxillary; and maxillary vertex occlusal radiographic views. Standard thermoluminescent dosimetry methodology was employed using a humanoid phantom of the skull. Multiple exposures were done for each view to ensure adequate precision. The absorbed doses to various locations following a single occlusal exposure are presented in centiGray (cGy). It was found that the absorbed dose values for occlusal radiography observed in this study were similar in magnitude to previously reported absorbed dose values for other forms of dental radiography. Values ranged from 0.0014 cGy to 1.301 cGy. The highest absorbed doses were generally the skin entrance doses. The results of this study provide an accurate, concise summary of surface and internal absorbed radiation doses for five commonly used occlusal radiographs. They can be used in the calculation of risk estimates for dental radiography, and may assist dentists in their discussions with patients concerned about radiation exposure.

Absorption↗
PubMed1995

[Latex allergy in children with spina bifida].

Latex allergy is a frequent happening in children with spina bifida or congenital urologic abnormalities. These patients have multiples exposures to derivatives of latex as part of the management increasing the risk of allergic reactions. We present three children who developed general anaphylactic reaction during urodynamic exploration with a rectal latex catheter. All patients showed positive skin test and positive latex specific IgE test (RAST). A prospective survey of 17 patients with spina bifida at the time of cystometry showed positive RAST levels in 7 (41%). Recommendations for prophylaxis are included, suggesting the avoidance of latex products in children with spina bifida since birth.

Adolescent↗
PubMed1996

Radiation-induced neoplastic transformation of human prostate epithelial cells.

We report the malignant transformation of human prostate epithelial cells (267B1) after multiple exposures to ionizing radiation. Carcinogenic progression of cells from immortal growth to anchorage-independent growth in soft agar to tumorigenicity in athymic mice resulted after a cumulative X-ray dose of 30 Gy. The tumors were characterized histologically as poorly differentiated adenocarcinomas, expressed prostate-specific antigen, and stained positive for keratin. No p53 or ras mutations were observed. Numerous chromosomal defects were noted on karyotypes after radiation exposure. However, chromosome 3 and 8 translocations were observed predominantly in the tumor outgrowths. These findings provide the first evidence of malignant transformation of human prostate epithelial cells exposed to ionizing radiation.

Animals↗
PubMed1997

Malignant transformation of human prostate epithelial cells by N-nitroso-N-methylurea.

We report the malignant transformation of adult human prostate epithelial cells after multiple exposures to the chemical carcinogen N-nitroso-N-methylurea. Such transformants showed morphological alterations and anchorage-independent growth in soft agar and induced carcinomas when transplanted into nude mice. No p53 or ras mutations were observed. Stepwise chromosomal changes in the progression to tumorigenicity were observed. Loss of the p arms of chromosome 8 (p10>pter) and chromosome 10 (p10>pter) and gain of the q arm of chromosome 8 (q10>qter) were only observed in the tumor outgrows. These findings provide the first evidence of malignant transformation of human prostate epithelial cells exposed to a chemical carcinogen.

Adult↗
PubMed1997

[Comparative physiopathology of Oestrus ovis (Linne 1761) myiasis in man and animals].

Oestrus ovis is an agent of a naso-sinusal myiasis of sheep and goats. This infestation is very frequent and induces clinical signs of rhinitis and sinusitis which are sometimes severe. The pathogenic role of this parasite has been explained until now exclusively because of its size, hooks and spines. Some recent studies indicate the involvement of local hypersensitivity with recruitment of numerous mast cells and eosinophils. Histological nasal mucosal tissue section examination from both sheep and goats showed the presence in considerable numbers of eosinophils and mast cells in lambs receiving single doses of artificial infection were twice as many as the number in control group. In animals subjected to multiple artificial infection the serous mast cell population increased 11-folds and that of mucous mast cells by 5-7 folds when compared with non-infected control groups. Similarly, the eosinophil counts were 17, 29 and 58 times greater in nasal septum, turbinates and sinus in infected groups than their control counter mates. The findings hence suggest that single infection is apparently tolerated by the host while massive cellular recruitment characterizes the cellular responses vis à vis multiple exposure. These reactive cells are localized mainly in the chorion layer just beneath the epithelium with only very few cells in the sub-mucosa level. It is, therefore, presumed that these cells are responsible in limiting parasite (larval) populations and in sustaining the hypersensitivity phenomenon at the site of tissue insult during infection. In naturally infected sheep the mean number of mast cells is only twice that present in parasite free animals. This result is remarkably different from that obtained in repeated artificial infections, probably associated to the difference in cellular response between adult sheep and lambs. It may also possibly explained as resulting from the immunodeficiency induced by parasite antigens. Human beings may be accidently infected. Larvae are deposited by adult flies into conjunctival sacs. Clinical signs of this zoonosis indicate that the pathophysiological processus are different than in animals. Examination of such cases did not confirm the existence of an accompanying allergic reaction in the process.

Animals↗