PubMed Health⌕ Search

Biomedical subjects

R Shaw

Publications and source records attributed to R Shaw.

At least 145 records · Page 8Linked to original sources
PubMed1980

Malacoplakia of the female genital tract.

Malacoplakia is an uncommon chronic granulomatous inflammation which most frequently involves the urinary bladder of middle-aged women and rarely affects the genital tract. In this paper 10 cases of female genital malacoplakia are reviewed, seven of which have been reported previously in the literature. Genital malacoplakia usually occurs in women 60 years of age or older and most frequently affects the vagina. Vaginal bleeding is a common presenting complaint and the lesion may simulate a malignancy. Four of the 10 patients were receiving corticosteroids at the time of diagnosis. Escherichia coli was cultured from urine or from the lesion itself in half of the cases. The disease appears to be an acquired defect in bactericidal function of histiocytes. Antibiotic therapy and surgical excision are effective, although a recurrence developed in one patient and was successfully re-excised.

Aged↗
PubMed1980

Early and late scavenging of anaesthetic gases.

The effectiveness of two waste gas scavenger devices, the Carstens box and the Ventex apparatus, with regard to nitrous oxide pollution was studied under comparable conditions in an operating theatre. The scavengers were brought into use in the early and late stages of induction of anesthesia, and nitrous oxide concentrations in the breathing zone and theatre peripheral air were measured. Both scavengers reduced nitrous oxide pollution at the sampling points. Similar reductions in nitrous oxide pollution in the breathing zone were obtained with both scavengers, but the Carstens box was more effective in reducing nitrous oxide pollution in the peripheral air.

Air Pollution↗
PubMed1980

Effects of low concentrations of nitrous oxide on rat fetuses.

The long-term inhalation of air polluted with nitrous oxide has been implicated in spontaneous abortions and fetal abnormalities in operating room personnel. Studies with 1% and 0.5% N2O in air have confirmed the adverse effects of dilute concentrations of N2O in pregnant rats. The present study was designed to determine the threshold concentration of nitrous oxide necessary to produce adverse responses in pregnant rats. Wistar albino rats were mated in an environmental chamber and conception confirmed by vaginal smears. Immediately thereafter, the rats were randomly divided into control and experimental groups. The control rats were exposed for 19 days to oil-free compressed air in an environmental chamber at a flow rate of 8.5 air changes per hour. Experimental animals were exposed continuously under identical conditions to concentrations of 0.0, 0.1%, 0.5%, or 0.025% N2O. On day 19 the gravid rats were killed. The corpora lutea of pregnancy were counted and related to the number of fetuses in the uterus. Fetuses were fixed, cleared, and their skeletons stained with alizarin red. Litter size, frequency of fetal resorption, and fetal crown rump measurements were significantly different following exposure to 0.1% N2O than they were in control rats or in rats exposed to 0.05% or 0.025% nitrous oxide, neither of which had any fetal effects. The suggested threshold level of 30 ppm (0.03%) N2O in humans may be unrealistically low.

Abnormalities, Drug-Induced↗
PubMed1979

Bile acids. LIX. Purification of 5 alpha-anhydrocyprinol by preparative high-performance liquid chromatography.

26,27-Oxido-5 alpha-cholestane-3 alpha,7 alpha,12 alpha-triol can be obtained in a homogeneous state in gram quantities by passing it through one PrepPak-500/Silica cartridge mounted in a Waters Assoc. preparative liquid chromatograph. The elution solvent was methanol-chloroform (1:14). The isolated material was analyzed for purity by several chromatographic means and by elemental analysis, and was finally characterized by the usual spectroscopic means. Gas-liquid chromatography of its trimethylsilyl ether indicated the formation of a tetrakis-trimethylsilyl-26-chloro derivative, in addition to the expected tris-trimethylsilylated substance. The structure of the former compound is deduced from the fragmentation and isotope abundance in its mass spectrum and from chemical principles.

Animals↗
PubMed1979

Competitive inhibitors of rabbit hepatic microsomal 12 alpha-steroid hydroxylase.

Rabbit hepatic microsomal 12 alpha-steroid hydroxylase which is stable to storage at -70 degrees C in the pellet form was assayed for activity with [5 alpha,6 alpha-3H2]cholestane-3 alpha,7 alpha-diol solubilized with Tween 80 since methanol was incapable of maintaining the sterol in aqueous solution. Under optimized conditions in phosphate buffer, pH 7.4, containing nicotinamide, magnesium chloride, and NADPH, the enzyme conversion appeared linear for the initial 10 min. The rate of hydroxylation was proportional to protein concentration up to 4 mg/ml. Apparent Km and Vmax were 71 microM and 323 pmol of product/mg of protein/min. Based on the known structural requirements of the enzyme system, competitive inhibitors were prepared with the C-12 position derivatized as an alkene, hydroxyl, or oxo functional group. A Dixon plot revealed that 5 alpha-cholest-11-ene-3 alpha,7 alpha,26-triol was the best inhibitor with an apparent Ki of 26 microM.

Animals↗
PubMed1979

Effects of cyclic AMP altering drugs on endotoxin-induced termination of pregnancy.

The effects of dibutyryl-cyclic AMP (DBcAMP), propranolol, and theophylline on endotoxin (LPS) challenged pregnant mice was determined by comparing the patterns of termination and times of fetal expulsion. Endotoxin isolated from wild type (WT) and Re chemotype mutant cells of Salmonella typhimurium was used. Wild type LPS caused the expulsion of the fetuses, while Re LPS primarily caused the resorption of the fetuses. The major change in pattern occurred in the propranolol treated Re LPS challenged group with a trend toward more expulsions and a decrease in uterine cyclic AMP (cAMP) levels to that approaching the group challenged with wild type LPS. The time of expulsion was also affected in the wild type LPS treated group, with propranolol hastening and DBcAMP and theophylline delaying the expulsion. These results support the hypothesis that uterine cAMP is involved in the expulsion of the fetuses.

Abortion, Spontaneous↗
PubMed1979

Chemical synthesis of three 14 alpha-hydroxymethyl cholestenols.

Reported herein are chemical syntheses of 14 alpha-hydroxymethyl-5 alpha-cholest-8-en-3 beta-ol, 14 alpha-hydroxymethyl-5 alph-cholest-7-en-3 beta-ol, and 14 alpha-hydroxymethyl-5 alpha-cholest-6-en 3 beta-ol. These compounds were obtained in pure form after repeated medium-pressure column chromatography of the mixture obtained by treatment of 3 beta-acetoxy-7 alpha,32-epoxy-14 alpha-methyl-5 alpha-cholestane with pyridine hydrochloride in refluxing acetic anhydride followed by reduction with lithium aluminum hydride. The compounds were characterized by their chromatographic properties and by the results of infrared, optical rotation, nuclear magnetic resonance, and low and high resolution mass spectral studies.

Cholestenes↗
PubMed1979

Gel permeation chromatography as a stability-indicating assay for human serum albumin.

It has been known for a considerable period of time that preparations of normal human serum albumin contain a amount of polymers and their formation appears to be related to the stability of human albumin solutions. This report describes a gel permeation chromatography technique using Sephadex G-150 to separate albumin molecules into monomers, imers, and polymers. In order to determine if this system could detect small changes in albumin solutions, 5% solutions of albumin were heat denatured and assayed. The changes which resulted from the heat denaturation were easily measurable. Additional experiments using 5% and 25% albumin solutions showed that this system could also detect changes in the amount of aggregation which occurred in these solutions with time. It therefore appears that this technique may be of value in assessing the stability of albumin solutions as measured by the formation of protein aggregates.

Chromatography, Gel↗
PubMed1978

Bile acids. LIV--mass spectra of conjugated bile acids.

The electron impact mass spectra of conjugated bile acids, their 5alpha-analogs and methyl esters of glyco conjugates were determined by direct insertion into the ion source and their fragmentation patterns were found to be basically similar to those of methyl esters of the free bile acids. The conjugates are additionally characterized by a significant loss of [NH2CH2CO2H] from the glycine moiety and [CH2 = CHSO3 H] from the taurine group. Several 5 alpha- and 5 beta-isomers can be differentiated, but no general pattern of recognition is discernable. Field desorption mass spectra contain [M + Na]+ and [m + Na]2+ ions.

Bile Acids and Salts↗
PubMed1978

Bile acids LVII. Analysis of bile acids by high pressure liquid chromatography and mass spectrometry.

Several high pressure liquid chromatographic methods for the separation of conjugated and free bile acids are presented. A mixture of synthetic conjugated bile acids has been separated by reverse-phase systems consisting of either a Waters Associated' "fatty-acid analysis" or a muBondapak/C18 column eluted with a mixture of 2-propanol/potassium phosphage buffer (pH 2.5 or 7.0). The major conjugated bile acids present in the gallbladder bile of obese subjects have been analyzed each in less than 30 min and quantitated with a U.V. detector set at 193 nm. Some of the 5 alpha- and 5 beta-isomers of conjugated bile salts could be resolved in straight-phase systems on Corasil II or muPorasil columns. Mass spectra of the conjugated bile acids obtained by electron impact were characteristics of the type of amino acid attached to the side chain, and the number of hydroxyl substituents on the nucleus. Most of the isomers could readily be differentiated by the relative intensities of the fragment ions.

Amino Acids↗
PubMed1978

Nitrous oxide contamination in dental surgeries using relative analgesia.

The concentrations of nitrous oxide were determined at various positions in four dental surgeries in which nitrous oxide sedation was used without scavenging. Contamination was present in all the surgeries, the greatest concentration being recorded at the dentist's nose and the least in the peripheral air. The reception area adjoining the surgeries was found also to be contaminated by nitrous oxide.

Air Pollutants↗
PubMed1978

Comparison of sampling techniques for studies of nitrous oxide pollution.

The retention of nitrous oxide in samples of nitrous oxide in air held in disposable plastic syringes, glass syringes and custom-made nylon film bags was studied by means of gas chromatography at intervals of 90 min, 24, 48 and 120 h after filling the containers. After 24 h the nylon bags retained a mean concentration of 94.5% of the original concentration of nitrous oxide. The disposable plastic syringes and glass syringes were unsatisfactory and retained only 80% of the original concentration of nitrous oxide after 90 min. These values decreased to 51% and 31% of the original concentration of nitrous oxide respectively at 24 and 48 h.

Air Pollution↗