PubMed Health⌕ Search

Biomedical subjects

D J Freeman

Publications and source records attributed to D J Freeman.

83 records · Page 5Linked to original sources
PubMed1978

New performed catheter and method for retrograde left atrial or complete left heart catheterization.

Employing a new catheter and technique complete retrograde left heart catheterization was accomplished in 96 of 100 consecutive patients. These 96 patients included 37 with ischemic heart disease, 13 of 17 with isolated aortic valve deformities, 11 with isolated rheumatic mitral valve deformities, 10 with combined rheumatic aortic and mitral valve deformities, and 25 with other problems. The only failures were in 4(of 27) patients with aortic valve deformities. No untoward complications occurred. The retrograde catheterization fluoroscopy time was usually less than 2 minutes. The shortest time was 44 seconds, the longest, 6 minutes and 2 seconds. These data indicate that this new catheterization method achieves safe, reliable (when the aortic valve is not deformed), simple, and rapid complete left heart catheterization. They further indicate it may be useful in assessing patients with mitral stenosis, pulmonary hypertension, hypertrophic obstructive cardiomyopathy, and left-to-right shunt problems.

Cardiac Catheterization↗
PubMed1977

In vitro and in vivo studies on the metabolism of estrogens and their sulfates in guinea pigs.

Labelled estradiol-17 beta(E2) or estrone (E1), when incubated with guinea pig liver slices, is metabolized by two main pathways. Part of each substrate is converted to estrone-3-glucuronide and estradiol-3-glucuronide. A further part of each is metabolized to estradiol-3-sulfate (E23S) and estrone-3-sulfate (E13S), which are interconverted. The latter conjugate appears to be the substrate for a 16 alpha-hydroxylase forming 16 alpha-hydroxyestrone-3-sulfate (16 alpha OHE13S). This, in turn, is further sulfurylated to yield 16 alpha-hydroxyestrone-3, 16-disulfate, accompanied by estriol-3,16-disulfate. A relatively small amount of tentatively indentified '6-hydroxyestrone disulfate accompanies these other two diconjugates. The guinea pig liver system suggests itself as a useful and relatively simple model for further study of 16 alpha-hydroxylation of E13S. The use of the latter as a natural subd E23S are present in liver, kidney, blood, gallbladder bile, intestine, uterus, and placenta after injection of labelled E2 into mature male and female guinea pigs. Some evidence has been obtained for the disulfate fraction (above) in liver and bile after injection of labelled E1.

Animals↗
PubMed1976

Metabolites of estradiol-17beta in guinea pig uterus late in pregnancy.

The metabolism of estradiol-17beta by the guinea pig uterus late in pregnancy was studied in vivo and in vitro. Whole uteri were examined for estrogen metabolites one hour following an intravenous injection of [3H]-estradiol-17beta or uterine sections were examined after incubation for one hour at 37 degrees C in medium containing [3H]-estradiol-17beta. In both instances uterine tissue metabolized estradiol-17beta to five products; estrone, estrone-3-sulfate, 17beta-estradiol-3-sulfate, estrone-3-glucuronide and 17beta-estradiol-3-glucuronide. Of the total radioactive products 11-43% were glucuronides, 17-26% were sulfates and 4-17% was estrone. These results indicate that the guinea pig uterus actively transforms estradiol-17beta into glucuronides and sulfates late in pregnancy.

Animals↗
PubMed1976

Changes in blood enzyme activity and hematology of rats with decompression sickness.

Plasma activities of lactic dehydrogenase (LDH), creatine phosphokinase (CPK), glutamic pyruvic transaminase (GPT), and alkaline phosphatase (ALP) were studied, along with hematological changes, in rats suffering from various degrees of experimental decompression sickness (DS). By 1 h after decompression, LDH and CPK activities were elevated in moderate and severe DS whereas GOT and GPT were elevated only in severe DS. ALP was reduced in all decompressed rats. Hematological changes indicated hemoconcentration, the degree of which paralleled the severity of DS. By 24 h after decompression, all enzyme activities were approaching control levels with the exception of GOT, which was further elevated from the 1-h value. The observed lung damage in rats with severe DS in conjunction with the hematologic and enzyme data suggested that hypoxemic-hypoxia, incident to bubble embolization of pulmonary vasculature, was a major factor in altering the blood enzyme pattern in DS. Serum enzyme data from two inadequately decompressed divers are also reported.

Alanine Transaminase↗
PubMedDate not supplied

Pharmacokinetic profiles of ceftazidime in cochlear perilymph, cerebrospinal fluid and plasma: a high-performance liquid chromatographic study.

A pharmacokinetic profile of the antibiotic ceftazidime was established for perilymph, cerbrospinal fluid (CSF) and plasma in 12 guinea pigs using the technique of high-performance liquid chromatography. The mean peak levels of 13.35 mg/l in perilymph and 140.54 mg/l in plasma were reached within the first hour after a single intravenous dose of 100 mg/kg. The CSF mean peak level of 5.36 mg/l, however, was not attained until 3 h after injection. The half-life was about 4 h in perilymph, more than 6 h in CSF and less than 2 h in plasma. Six hours following administration, the perilymph drug concentration remained higher than the plasma level. The study indicates that ceftazidime has excellent penetration into perilymph. It is concluded that ceftazidime should be a very useful agent in the treatment of bacterial labyrinthitis caused by susceptible organisms.

Animals↗
PubMedDate not supplied

The risk of lung cancer from polycyclic aromatic hydrocarbons in Sydney air.

Air pollution often is suggested as being partly responsible for an increased incidence of lung cancer in cities. A problem with epidemiological studies is that the comparatively-small effect of air pollution is difficult to identify in the presence of larger and variable effects of cigarette smoking and other factors. This article describes an alternative approach to the estimation of cases of lung cancer that may be a result of air pollution. The concentration of a number of carcinogenic polycyclic aromatic hydrocarbons has been measured at two sites in Sydney and the relative contributions from various pollutant sources have been deduced. By means of a source inventory and an atmospheric dispersion model, concentrations have been derived for the whole Sydney region. Lung-cancer induction is calculated from the population that is exposed and the concentration of benzo(a)pyrene, which is used as a surrogate for the carcinogenic products of incomplete combustion. For the Sydney region, it is estimated that about 30 lung cancers a year could arise from polycyclic aromatic hydrocarbons in the ambient air.

Air Pollutants↗