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Biomedical subjects

A Jones

Publications and source records attributed to A Jones.

At least 559 records · Page 31Linked to original sources
PubMed1987

The acute haemodynamic effects of intravenous verapamil in patients with chronic obstructive airways disease.

The haemodynamic effects of a single intravenous dose of verapamil have been investigated in patients with chronic obstructive airways disease both during an acute exacerbation and when in a stable clinical condition and compared with the effects of oxygen administered by nasal cannulae. In five patients studied during an episode of acute on chronic hypoxaemia (mean PaO2 = 5.4 kPa) there was a significant fall in pulmonary vascular resistance (p less than 0.03) following intravenous verapamil (10 mg) without any reduction in PaO2, cardiac index or oxygen delivery. Subsequent administration of oxygen by nasal cannulae at 2 l/min for 30 min produced similar pulmonary haemodynamic changes: pulmonary vascular resistance fell by 17 +/- 3 per cent following oxygen and by 22 +/- 4 per cent following verapamil. In a similar group of five patients in a stable clinical condition (mean PaO2 = 7.3 kPa) neither oxygen nor verapamil administered during acute exacerbations produced any significant changes in pulmonary vascular resistance, cardiac index or oxygen delivery.

Acute Disease↗
PubMed1987

Vaginal müllerian stromal sarcoma. A case report.

Primary malignancies of the vagina are among those encountered most rarely in the female reproductive tract. Even more rare are primary vaginal sarcomas. The fourth case of vaginal müllerian stromal sarcoma is reported on here.

Aged↗
PubMed1986

Factors influencing the activity of the trometamol salt of fosfomycin.

The antibacterial activity of trometamol fosfomycin and its potentiation by glucose-6-phosphate were found to vary considerably in different culture media, although not all bacteria tested were equally affected. In general, the lowest MICs were obtained in the presence of glucose-6-phosphate in nutrient broth and Eugonbroth. The influence of inoculum size, pH and potentiation by glucose-6-phosphate were investigated by agar incorporation MIC titrations on nutrient agar. The activity of trometamol fosfomycin against many strains increased as the pH was lowered from 7.9 to 5.5. Only 9% of the strains showed an inoculum effect when tested at pH 5.5 in the presence of glucose-6-phosphate compared with 37% of the strains tested at pH 7.1 and 22% of the strains tested at pH 7.9. In the absence of glucose-6-phosphate, about 10% of the strains showed an inoculum effect at all three pH levels. The addition of glucose-6-phosphate to culture media seems reasonable for the testing of fosfomycin susceptibility.

Bacteria↗
PubMed1986

A complicated case of appendicitis.

A case is presented of acute appendicitis in a 50-year-old man with unsuspected carcinoma of the right colon. This association is emphasised as acute appendicitis is an important marker of colonic carcinoma in the older age group. The value of doing routine barium enema examination in these patients after appendicectomy is discussed. Further unusual features of this carcinoma were radiographically visible calcification and spread into the right kidney.

Acute Disease↗
PubMed1986

Sensitivity patterns of coagulase-negative staphylococci from neonates.

Coagulase-negative staphylococci from neonates on two special care baby units were collected and the sensitivity patterns to 18 antibiotics were compared. The two units had different antibiotic policies and this correlated with different sensitivity profiles for the isolates. Netilmicin was shown to be the most active aminoglycoside and cefamandole the most active cephalosporin.

Aminoglycosides↗
PubMed1986

Comparative pharmacokinetics of cefamandole, cefuroxime and cephradine during total hip replacement.

Serum, bone and tissue levels of the three cephalosporins, cefamandole, cefuroxime and cephradine were determined in 60 patients given a single 1 g dose intravenously before total hip surgery and two similar doses at 8 h intervals. The levels achieved were comparable for all three antibiotics, hence the choice of prophylactic antibiotic for total hip replacement should be guided by the pathogens causing infection and cost of the antibiotic.

Aged↗
PubMed1986

Semicontinuous and Continuous Production of Chloroperoxidase by Caldariomyces fumago Immobilized in k-Carrageenan.

Three strains of Caldariomyces fumago were immobilized in 4% k-carrageenan and tested for semicontinuous production of chloroperoxidase (CPO). Over an 80-day period, growing in defined medium, C. fumago strains CMI 89362 and ATCC 11925 produced enzyme concentrations of 99 and 71 mg/liter, respectively, during six production periods of 12 to 14 days, while C. fumago DAOM 137632 produced only 24 mg of CPO per liter during six growth periods of 10 days. CPO production was unaffected by various regimens of washing between transfers. Mycelial growth was primarily restricted to the head surface, and bead size increased linearly with time. Attempts to restrict growth but maintain CPO production were unsuccessful. Pigment production, fructose utilization, and pH change in the immobilized cell cultures compared closely with the growth characteristics of free cell cultures. By using an airlift tower fermentor with an external loop run with continuous medium replacement of 20 ml/h (D = 0.016), strain CMI 89362 in bead form produced CPO at 40 mg/liter for 11 days.

Journal Article↗
PubMed1986

Manganese and antibiotic biosynthesis. I. A specific manganese requirement for patulin production in Penicillium urticae.

The effect of trace metal nutrition on the functioning of the patulin biosynthetic pathway in submerged cultures of Penicillium urticae (NRRL 2159A) was examined by both chromatographic and enzymological means. Comprehensive metal ion analysis showed generally low levels of contaminating metal ions in media components. Of eight metal ions examined, only manganese strongly influenced secondary metabolite production. In control cultures or cultures deficient in calcium, iron, cobalt, copper, zinc, or molybdenum, pathway metabolites appeared in the medium at about 25 h after inoculation. The first pathway-specific metabolite, 6-methylsalicylic acid, accumulated only transiently before being converted to patulin whose concentration steadily increased. In manganese-deficient cultures, however, 6-methylsalicylic acid continued to accumulate, with only minor amounts of patulin being produced. Additionally, a marker enzyme for the pathway showed only 0-20% of control activity. Clear dose responses (patulin versus manganese) were found in different media, with no effect on growth yield. Addition of manganese to depleted cultures at 18, 26, or 36 h resulted in increasing marker enzyme activity and patulin concentrations. It is concluded that manganese exerts a specific, positive effect on patulin biosynthesis and may in some way control the section of the patulin pathway occurring after 6-methylsalicylic acid.

Acyltransferases↗
PubMed1986

Manganese and antibiotic biosynthesis. III. The site of manganese control of patulin production in Penicillium urticae.

Although manganese had been shown to be an essential requirement for patulin biosynthesis, its site of action was unknown. Four possibilities were considered. A manganese requirement for the second pathway enzyme, a decarboxylase, was discounted since mid and late pathway intermediates were not converted to patulin in manganese-deficient cultures. A major disruption in primary metabolism and hence secondary metabolism was discounted since eight primary metabolism enzymes showed no evidence of unusual changes in specific activity when normal and manganese-deficient cultures were compared. Inhibitor studies using actinomycin D and cycloheximide showed that there was no activation of preexisting enzyme proteins and that manganese did not influence translation. The inhibitor studies did show, however, that manganese exercised its effect on patulin biosynthesis by influencing the coordinate appearance of pathway enzymes though an effect at the level of transcription.

Alcohol Oxidoreductases↗
PubMed1986

Postnatal ovarian follicle development in hypogonadal (hpg) and normal mice and associated changes in the hypothalamic-pituitary ovarian axis.

Significant uterine growth occurred in normal and hypogonadal (hpg) mice between Days 7 and 21 but thereafter no further growth was observed in hpg mice. The ovaries of hpg mice were significantly smaller than those of normals at all ages, but there was no significant difference between the number of non-growing follicles in the ovaries of mutants and their normal littermates at any age studied, and normal and hpg mice showed a marked reduction in the number of non-growing follicles during the first month of life. The size and composition of the growing follicle population in hpg mice, however, differed markedly from those in normal animals and by 21 days of age the number of growing follicles in mutants was significantly reduced. There was no significant difference in the number of Type 3b follicles before 60 days of age, but the number of all other follicle types was significantly less in hpg mice at all ages studied. Follicles in which the antrum is fully developed (Type 7 and 8) were never seen in the ovaries of mutants and corpora lutea were never observed. Interstitial tissue development was also very poor in hpg ovaries. The hypothalamic GnRH content in normal mice remained low until Day 20, before rising sharply to adult levels (approximately 800 pg) between Days 20 and 30. The pituitary FSH content increased over the first 10 days of life to reach a peak of about 5000 ng, before declining to the adult value of about 2000 ng by Day 30, whilst the plasma FSH concentration was high in the first 10 days, but fell to adult levels over the next 20 days. Pituitary LH content increased significantly between Days 5 and 10 to reach the adult level of about 600 ng. Hypothalamic GnRH was undetectable at all ages in hypogonadal mice, but the pituitary content of FSH and LH had risen to the attenuated mutant adult value by Day 15, and unlike normals, plasma FSH concentrations were not elevated during the neonatal period. These results suggest that minimal gonadotrophic stimulation of the ovary from birth has no effect on the total number of follicles but reduces the number of growing follicles and prevents follicle growth beyond the early antral stage. Gonadotrophins therefore appear to have a role in the initiation and continuance of follicle growth in the adult mouse.

Animals↗
PubMed1985

Amino acid sequence homologies between rabbit, rat, and human serum retinol-binding proteins.

The main transporting protein for vitamin A in rabbit serum, the retinol-binding protein (RBP), was isolated and its amino acid sequence determined. Rabbit RBP was found to be highly homologous to human RBP, whose amino acid sequence was elucidated earlier, and to rat RBP. The rat RBP sequence was obtained by combining information deduced from the nucleotide sequences of two overlapping cDNA clones with the NH2-terminal sequence of the isolated protein determined by automated Edman degradation. The identity between the three proteins is approximately 90%. The high degree of homology between RBP molecules from different species is probably explained by the fact that RBP participates in at least three types of molecular interactions: in the binding of prealbumin, in the interaction with retinol, and in the recognition of a specific cell surface receptor. All these interactions should lead to a conservation of RBP structure. The amino acid differences between rabbit, rat, and human RBP are discussed in light of the recent elucidation of the three-dimensional structure of human RBP. Hybridization of a probe isolated from a rat RBP cDNA clone to restriction enzyme-digested genomic DNA from rat and mouse suggests that RBP is encoded by a single gene.

Amino Acid Sequence↗
PubMed1985

The measurement of radiation doses from P32 chromic phosphate therapy of the peritoneum using SPECT.

Single photon emission computed tomography (SPECT) has been shown to be of value in estimating the radiation dose to the peritoneum from 32P therapy. Simple dosimetry calculations, assuming uniform irradiation of tissue, indicate that radiation doses of approximately 40 Gy to the peritoneal surface are achieved. However, the images show that the radionuclide distribution is non-uniform, giving rise to radiation dose variations of at least a factor of 10.

Chromium↗
PubMed1985

Maturation of the response of human fetal pancreatic explants to glucose.

The release of insulin from the human pancreas in response to glucose is known to be either poor or absent in the fetus, whereas in the infant and adult, the response is much greater. The maturation of this response was examined systematically in this study using pancreases that were initially obtained at 14-20 weeks gestation and maintained either in culture alone or by passaging them in diabetic nude mice. Stimulation with glucose was carried out in vitro using tissue of ages ranging from 14 to 58 weeks. A response to glucose was initially seen at 25 weeks and this dramatically increased in the fetal tissue that had reached an age of 55 weeks or more. One of the nude mice used for passage developed normoglycaemia and when the pancreatic implant of age 52 weeks was removed, diabetes recurred. Our findings support the idea of the use of human fetal pancreatic tissue in the treatment of diabetes mellitus.

Age Factors↗