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Biomedical subjects

J Foster

Publications and source records attributed to J Foster.

At least 37 records · Page 2Linked to original sources
PubMed1989

The neuroteratogenicity of procarbazine hydrochloride in the rat: histopathological and immunocytochemical aspects.

Procarbazine hydrochloride, and antineoplastic drug, was administered to pregnant rats from days 13 to 16 of gestation at doses of 0, 1, 5 and 15 mg per kg as part of a behavioural study. Histological examination of the brains from the offspring at 12 to 15 weeks of age revealed cerebral atrophy, which increased in severity with increasing dose, together with a reduction in neuronal numbers, with no apparent effect upon the astrocyte and oligodendrocyte populations.

Abnormalities, Drug-Induced↗
PubMed1989

Comparative study of early-season prophylaxis using ivermectin with lungworm vaccination in the control of parasitic bronchitis and gastroenteritis in cattle.

Twenty-four first-season calves were randomly allocated to three similar groups (1-non-treated controls; 2 - vaccinated against lungworm; 3 - treated with ivermectin 21, 56 and 91 days after turnout) and set-stocked on separate pastures. Parasitic bronchitis became evident in the controls and signs of parasitic gastroenteritis were seen later in the vaccinates, but the ivermectin-treated calves remained healthy. After autumn housing, all were kept as a single group for the winter. The following summer, six of the ivermectin-treated animals and their matching vaccinates were grazed together, without further prophylaxis, along with six first-season calves. The latter displayed evidence of mild but debilitating pulmonary and gastrointestinal parasitic disease while both groups of yearlings remained healthy (with the exception of one diarrhoeic vaccinate). Thus, the immune status of the ivermectin-treated animals appeared to be comparable to that of the vaccinates. This conclusion was supported by parasitological observations and by artificial challenge at the end of the second grazing season.

Animals↗
PubMed1989

Cellular mechanisms of toxicity and tolerance in the copper-loaded rat. III. Ultrastructural changes and copper localization in the kidney.

The distribution of copper and related changes have been studied in copper-loaded rat kidneys at the ultrastructural level by X-ray electron probe microanalysis, in order to clarify the pathogenesis of copper-induced damage and subsequent recovery in this organ. Male rats fed a high copper diet (1500 ppm) for 16 weeks were killed at intervals; their kidneys were removed and portions of kidney cortex fixed in 4% paraformaldehyde and 2% glutaraldehyde for electron microscopy: other samples were analysed for copper by AA spectrophotometry. Increasing copper accumulation was associated with progressive PCT cell disarray and characterized by irreversible nuclear damage coincident with the intranuclear accumulation of Cu, S, P, and Ca. Copper was also identified within structurally intact lysosomes associated with Zn and Fe (Type I lysosomes) or P and S (Type II lysosomes, putative Cu-MT). Subsequent copper decline and tubular recovery was associated with the facilitated lysosomal sequestration of copper and excretion of copper-containing cell products into the tubule lumina, Cu-MT and alpha-2 urinary protein-copper. The cytotoxicity of copper in the kidney, as well as the liver, is associated primarily with irreversible nuclear damage, whereas lysosomal copper sequestration protects the cell from injury.

Animals↗
PubMed1988

Microsomal cytochrome P-452 induction and peroxisome proliferation by hypolipidaemic agents in rat liver. A mechanistic inter-relationship.

Eight structurally diverse hypolipidaemic agents have been examined for their ability to induce the microsomal cytochrome P-452-dependent fatty acid hydroxylase system and the enzymes of peroxisomal beta-oxidation in rat liver. Using a specific ELISA method, we have shown that the cytochrome P-452 isoenzyme is induced up to ten fold by hypolipidaemic challenge, concomitant with a pronounced elevation of the peroxisomal beta-oxidation enzymes, mirrored by an increase in peroxisomal volume as determined morphometrically. In addition, the induction of cytochrome P-452 is accompanied by a decrease in the activities of cytochromes P-450b and P-450c as measured by benzphetamine N-demethylase and ethoxyresorufin O-deethylase activities respectively, the latter being more extensively reduced by hypolipidaemic treatment. A hypothesis is presented whereby an early biological response is the hypolipidaemic induction of microsomal cytochrome P-452 resulting in omega-hydroxy fatty acids and their subsequent further oxidation to dicarboxylic acids, the latter providing the proximal stimulus for peroxisomal proliferation.

Animals↗
PubMed1988

Heroin users in general practice: ascertainment and features.

A case-control study of heroin users in general practice showed a prevalence of roughly two per 1000 of the urban population or four per "average" general practice list of patients. A method of studying heroin users who attend general practice was used that has advantages over existing techniques. Thirty six heroin users had a statistically significantly higher yearly doctor-patient consultation rate than a group of matched controls. More heroin users also failed to attend appointments than controls. When consultations directly related to heroin and its effects were excluded, however, the consultation rates in the two groups were similar. The heroin users did not have an excess of psychiatric disorder or disturbed family background compared with controls but had a noticeable history of dishonest and violent behaviour towards medical staff. A high proportion of heroin users in the study were antibody positive for the human immunodeficiency virus. General practitioners should take advantage of their frequent contacts with heroin users and their families to give them support and counselling about the acquired immune deficiency syndrome.

Family Practice↗
PubMed1988

Splenic resection with the Contact Nd:YAG laser system.

Splenic resection in the dog was proven to have decreased blood loss (52%), decreased operating time (44%), and decreased surgical manipulation using the SLT Contact Nd:YAG Laser System with the synthetic sapphire probe, as compared with the noncontact CO2 laser. Tissue damage and hematologic changes were minimal and equivalent in both laser systems. The overall ease of use and operating technique was subjectively better with the contact Nd:YAG laser, and the danger of scattered and reflective beam damage was eliminated. The contact Nd:YAG laser with the synthetic sapphire probes offers a significant advantage over the noncontact CO2 laser in the resection of splenic tissue. Future applications in pediatric surgery now need to be evaluated.

Animals↗
PubMed1988

Recent clinical and epidemiological trends in parasuicide in Edinburgh and Oxford: a tale of two cities.

This is a report of clinical and epidemiological trends in parasuicide in Edinburgh and Oxford over the period of 1976 to 1984. Rates of parasuicide declined in both cities, but more markedly among women than men. Male rates tended to be higher in Edinburgh and female rates higher in Oxford. Age-specific rates were similar for the two cities in 1983-84, with peak rates for females among 15-19 year olds and those for males among 20-24 year olds in Edinburgh and 25-34 year olds in Oxford. Parasuicide incidence was higher in lower social class groups and among the unemployed in both cities. During the study period there was a massive decline in barbiturate overdoses, a more modest decline in minor tranquillizer overdoses but, in Oxford, a marked increase in self-poisoning with paracetamol. By the end of the study period the proportion of patients receiving a diagnosis of drug addiction had doubled in Edinburgh, although it had remained fairly constant in Oxford. There were differences in patterns of aftercare offered to patients in the two cities; these almost certainly reflect differing clinical policies.

Adolescent↗
PubMed1988

Discordant uptake of technetium-99m DISIDA and technetium-99m sulfur colloid in an amebic abscess.

Hepatobiliary imaging in a patient with an amebic abscess showed an early cold defect that later showed rim enhancement. A Tc-99m SC scan did not show prominent flow (making hepatoma unlikely) and showed the previously noted defect to appear larger and without rim enhancement. The differential damage to Kupffer cells and hepatocytes or edema may account for these findings. Amebic abscess should be included in the differential diagnosis of lesions that give increased Tc-99m IDA but cold Tc-99m SC images.

Adult↗
PubMed1987

Oxfendazole pulse release intraruminal devices and bovine parasitic bronchitis: comparison of two control strategies in a field experiment.

Lungworm-infected seeder calves were used on two 1.41 ha paddocks to ensure that groups of 11 susceptible trial calves would be exposed to heavy early season challenge with Dictyocaulus viviparus. This produced conditions for an artificially severe test of two control strategies. The first employed a front-loaded oxfendazole pulse release bolus, ie, an intraruminal device which released one therapeutic anthelmintic dose immediately and five subsequent pulses at approximately three-weekly intervals. These front-loaded boluses were given to five of 11 calves on one paddock as soon as parasitic bronchitis had become clinically obvious (34 days after turnout) while the remaining six calves were kept as untreated controls. Clinical signs quickly subsided in the treated animals and no further respiratory problems occurred despite continued exposure to reinfection. The other control strategy involved the administration at turnout of an oxfendazole pulse release device which released the first of five anthelmintic doses approximately three weeks after administration, to all 11 calves on the other paddock. This strategy was almost completely successful in preventing patent infections from establishing and reduced the infectivity of the pasture in August and September by 94.1 per cent as shown by tracer calf studies. The calves treated at turnout performed better than the calves treated with the front-loaded boluses for most of the season and had an average weight-gain advantage of 20.4 kg at housing (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Insulin-like growth factor I, somatomedin C, induces the synthesis of tropoelastin in aortic tissue.

The action of IGF-I (insulin-like growth factor I) on the synthesis of tropoelastin in chick embryonic aortae was examined. Maximal and selective stimulation of the relative (40%) and absolute (145%) rates of tropoelastin synthesis over control occurred at an IGF-I concentration of 100 ng/ml of medium. Parallel to the increase in synthesis was a 92% increase in the amount of tropoelastin activity per 100 ng of poly (A)+ RNA translated in a cell-free system. The relative rate of tropoelastin synthesis achieved at maximal stimulation is greater than that observed during normal aortic embryogenesis. The stimulatory action of the hormone on elastin synthesis appears to be at a pretransitional level perhaps involving increased transcription or stabilization of the tropoelastin mRNAs. These results suggest that IGF-I may play a key role in the regulation of elastogenesis in arterial tissue.

Animals↗
PubMed1987

Emergence of resistance to ceftazidime during therapy for Enterobacter cloacae infections.

The mechanism of resistance to ceftazidime in two clinical isolates of Enterobacter cloacae that emerged during therapy with broad-spectrum beta-lactam antibiotics was studied. Both isolates acquired broad resistance to advanced-spectrum beta-lactam drugs other than imipenem. Biotyping confirmed strain identity in both cases, and no new plasmids were detected in the resistant isolates. Both resistant isolates produced beta-lactamase constitutively. Slow but definite hydrolysis of ceftazidime was demonstrated by using purified beta-lactamase in a spectrophotometric assay. Further evidence that beta-lactamase is responsible for resistance in these organisms was provided by the demonstration that cefoxitin, a potent inducer of beta-lactamase, antagonized the activity of ceftazidime against these isolates. This antagonism could be prevented by inhibition of derepression of beta-lactamase with clindamycin. Clindamycin also prevented regrowth of ceftazidime-treated cells in time-kill studies and markedly reduced production of beta-lactamase in induced cultures at concentrations as low as 2 micrograms/ml.

Adult↗
PubMed1987

Intraoperative ultrasound of the liver. An important adjunctive tool for decision making in the operating room.

Forty-nine patients operated on for liver or other pathologic processes were examined intraoperatively with special ultrasound transducers during surgical exploration of the abdomen. Subjects were evaluated because of known or suspected disease of the liver. All patients were examined using sterile technique. Prospective diagnosis and retrospective analysis of data were used. In 55% of subjects, no new information was obtained. In 19%, new information was gathered that changed the surgical approach. In 14% of patients, new information was obtained but it was such that no change in the therapeutic approach was needed. In 12% of patients, although no new information was gathered by the use of intraoperative ultrasound, a change in the surgical approach and management of the patient was still possible because of intraoperative ultrasound. These studies show that the routine use of ultrasound during intraoperative procedures, particularly when involving hepatic structures, is a clinically useful technique. In many instances, it will change the course of management.

Evaluation Studies as Topic↗
PubMed1987

Field evaluation of the oxfendazole pulse release bolus for the chemoprophylaxis of bovine parasitic gastroenteritis: a comparison with three other control strategies.

Three trials were conducted in southern England involving 120 autumn-born calves to evaluate the ability of an oxfendazole pulse-release intraruminal device (OPRB) to control parasitic gastroenteritis (PGE). Matched groups were set-stocked on adjacent paddocks. One group received an OPRB at turn-out; one was treated with an alternative chemoprophylactic programme; while the third acted as an untreated control. In each trial clinical PGE occurred in the latter group but not in OPRB or alternative strategy groups. The OPRB, the morantel sustained release bolus (MSRB) and fenbendazole administered at 3 and 6 weeks after turn-out gave similar weight-gain benefits when compared with untreated controls (P less than 0.01), but the growth rate of animals given regular levamisole treatments from July to housing was significantly poorer than the matching OPRB group (P less than 0.05) although better than controls. Faecal egg-output of OPRB calves was reduced by 97.0-99.9% compared with 95.5 and 58.9% for MSRB and fenbendazole treatments. Consequently, the late summer/autumn peaks in pasture larval counts were considerably reduced in all treatment groups other than the late-season levamisole strategy which reduced overall egg-output by only 37.6%. Serum pepsinogen and gastrin values confirmed a greater degree of abomasal disturbance in calves grazing on the more highly contaminated pastures. Incidental lungworm infections became clinically apparent in the control groups of two trials but not in any OPRB or alternative treatment group.

Animals↗
PubMed1987

Prevalence of Chlamydia trachomatis infection in homosexual men.

Chlamydial cell culture isolation rates from 51 unselected homosexual men were 9.3% from the urethra, 4.3% (pharynx), and 6.5% (rectum). All the positive cultures showed extremely few inclusions. Direct immunofluorescence with the Microtrak reagent (Syva) was an acceptable alternative technique for non-genital sites, whereas the infectious disease enzyme immunoassay (IDEIA) (Boots-Celltech) was unsuitable.

Chlamydia Infections↗
PubMed1987

Interactions between chemoprophylaxis and immunity to bovine parasitic gastroenteritis and bronchitis: pilot studies using an oxfendazole pulse release bolus.

In separate experiments, the immune status of six matched pairs of yearling heifers from a field trial in which both parasitic gastroenteritis and husk had occurred in control animals, was tested with a single massive challenge of either Dictyocaulus viviparus or Ostertagia ostertagi. The clinical responses of untreated controls and animals that had carried an oxfendazole pulse release intraruminal device (OPRB) were in all cases similar (with the exception of one lung-worm-challenged control that succumbed to a fulminating pulmonary hypersensitivity reaction), indicating that both groups possessed comparable degrees of protection. Faecal larval/egg-output data and serum gastrin levels, however, suggested that larger worm populations had established in the OPRB cattle.

Animals↗
PubMed1987

Recalcitrant pancreatitis: eventual control by antioxidants.

A woman, 61 years of age at her first attack of pancreatitis, had further attacks every few months during the next two years despite cholecystectomy for gall stones, and pancreato-duodenectomy for pancreas divisum and duodenal diverticulum. Since starting treatment with antioxidants, she has been free of attacks for two years.

Antioxidants↗