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Biomedical subjects

M Joyce

Publications and source records attributed to M Joyce.

At least 55 records · Page 3Linked to original sources
PubMed1992

Modulation of eicosanoid production by human alveolar macrophages exposed to silica in vitro.

Repeated inhalation of silica dust can lead to inflammation and fibrosis in human lung and in experimental animal models. The alveolar macrophage is believed to play a pivotal role in this process. Numerous macrophage-derived growth factors, cytokines, and arachidonic acid metabolites have been shown to contribute to inflammation and fibrosis. The objective of this study was to determine the eicosanoid production by human alveolar macrophages in response to silica exposure in vitro and to assess the contribution of alveolar macrophages to silica-induced fibrosis and inflammation. Macrophages were obtained from healthy volunteers and were incubated for 3 or 24 hr in the presence of silica (100, 60, and 0 micrograms/mL). Supernatants were removed for eicosanoid analysis. Eicosanoids were analyzed by both high performance liquid chromatography and radioimmunoassay. The data suggest that silica causes an increased release of leukotriene B4, leukotrienes C4/D4/E4, and 5-hydroxyeicosatetraenoic acid (5-HETE) after 3 hr and decreases in prostaglandin E2 and thromboxane B2 production after 24 hr of exposure to 100 micrograms/mL silica. In addition, 12-HETE and 15-HETE production remained unchanged at either time point. These opposing effects seen with the metabolites of lipoxygenase and cyclooxygenase pathways could contribute to silica-induced fibrosis. The pattern of eicosanoid production after exposure to silica was different from that obtained when macrophages were stimulated with lipopolysaccharide for 3 or 24 hr, indicating that the response to the particles was not just due to general cellular activation.

Adult↗
PubMed1992

Sexual differences in lipoprotein composition in a family with dyslipidemic hypertension with premature atheroschlerosis: deficiency of high-density lipoprotein-L and high-density lipoprotein-M "apolipoprotein-I alone" particle.

This article describes a family with a high incidence of premature atherosclerosis and primary hypertriglyceridemia in the women. The lipoprotein composition of this family was investigated with a new methodology that combines gradient ultracentrifugation to isolate lipoprotein subfractions with high-performance liquid chromatography to quantitate apolipoproteins. The major lipoprotein abnormalities that were identified in the hyperlipidemic women in this family were (1) an increased mass of very low density lipoprotein (VLDL) and intermediate density lipoprotein (IDL) with triglyceriderich VLDL but normal IDL composition; (2) triglyceride-rich low-density lipoprotein (LDL) with normal cholesterol and apolipoprotein B concentrations; (3) a relatively normal total mass of high-density lipoprotein (HDL)-L and HDL-M but with a reduction in the apolipoprotein A-I/A-II ratio and a decrease in the cholesterol to triglyceride ratio; (4) an elevation of HDL-D apolipoprotein A-I. The reduction in the apolipoprotein A-I/A-II ratio was also seen in the hyperlipidemic men and in most of nonhyperlipidemic family members and was the most common lipoprotein abnormality that was identified in this family (9 of 11 family members who were not on lipid-lowering medications were affected). The hypertriglyceridemic women appeared to have an increase in the "A-I + A-II" HDL particles in all subfractions and an increase in the "A-I alone" particles in HDL-D. These increases provided the apparently normal total mass of HDL that was observed in these women. These increases in HDL were not seen in the hypertriglyceridemic men. We conclude that a deficiency of the "A-I alone" particle in HDL-L and HDL-M may contribute to the premature atherosclerosis that was seen in this family and that it appears to precede the appearance of hypertriglyceridemia. The increase in the "A-I + A-II" HDL particles did not appear to provide the same protection as would be expected from "A-I alone" HDL.

Adult↗
PubMed1991

Proliferative inhibition of human breast carcinoma cells by high concentration estradiol does not alter radiosensitivity.

The proliferation of ER+ malignant mammary epithelial cells (MMEC), MCF-7 and T-47D, was markedly inhibited by 10 microM 17 beta-estradiol (E2), while the ER- line, MDA-MB-231, was minimally affected. This concentration of E2 did not alter the proportion of non-viable cells or the plating efficiency. The decrease in proliferation was not associated with any consistent alteration in the cell kinetic profile between lines, though there was clearly no dominant cell cycle re-assortment after a two day incubation. Colony forming ability after exposure to ionizing irradiation was compared for proliferating and confluent MMEC to cells incubated in 10 microM E2 for two days. The presence of E2 resulted in no significant differences for any of the linear quadratic curve fitting parameters or for mean inactivation doses for both subconfluent and confluent cultures. Further, 10 microM E2 had no effect on the ability of cells to recover from split radiation fractions. There were no differences in the amount of DNA single strand break induction with E2, but there was a significant shortening in the repair halftime with E2 for the ER- MDA-MB-231 cells. Though high concentrations of E2 can markedly inhibit the proliferation of ER+ MMEC, this does not alter sensitivity to ionizing irradiation.

Breast Neoplasms↗
PubMed1991

Chronic tophaceous gout. A case report.

A review of gout is presented, followed by a discussion of the current medical literature on diagnosis, differential diagnosis, staging, and treatment. Chronic tophaceous gout is not as prevalent as it once was because of early diagnosis and treatment, but it is still encountered in the podiatric practice. A severe case of chronic tophaceous gout is presented. The patient was successfully treated by surgical intervention. Although surgery may be avoided in most cases, it is indicated when intractable pain, loss of motion, and massive joint destruction are present.

Chronic Disease↗
PubMed1990

Detection and measurement of simulated early rheumatoid lesions of the hand using digital subtraction radiography.

The ability of digital subtraction radiography, a new technique to detect and quantify small bone lesions, is demonstrated. Discrete lesions in the metacarpals of cadaver hands simulated erosive bone loss. Radiographs made before and after removal of bone were digitized and subtracted. Density changes on subtraction images were determined, and bone loss was estimated by an automatic procedure that compared changes in radiographic density with a calibration wedge included in the radiographs. Comparison of estimated bone loss with the weight of bone removed showed reproducible detection and measurement of bone lesions as small as 4.6 mg, a size undetectable using current radiographic methods. Subtraction radiographs of bone chips overlaid on the hand of a volunteer indicated detection limits were similar in vivo. This technique enhanced the radiographic visibility of erosive lesions and thus has the potential to improve the detection of subtle bone changes in clinical settings.

Arthritis, Rheumatoid↗
PubMed1990

Effect of lignocaine on coronary blood flow, systolic myocardial function and myocardial high energy phosphate stores in swine.

1. To investigate the effect of lignocaine upon coronary blood flow, myocardial systolic wall function and high energy phosphate stores, lignocaine was administered as a rapid intravenous injection to 14 open chest anaesthetized swine. 2. Before and after injection, measurements were made of coronary blood flow by electromagnetic flow probe, per cent wall thickening by ultrasonic crystals, adenosine triphosphate (ATP) and creatine phosphate (CP) content by myocardial biopsy, and arterial pressure by central aortic catheter. The animals were divided into two groups based on whether or not they received a continuous low-dose infusion of lignocaine prior to the study. Group I received the continuous low-dose infusion of lignocaine and group II did not. 3. With a 2 mg/kg lignocaine injection, peak diastolic coronary flow rose significantly in groups I and II by 27 +/- 7 and 29 +/- 7% respectively. This was followed by a significant decline in per cent wall thickening in groups I and II of -11 +/- 2 and -19 +/- 6% respectively. In group I myocardial CP content decreased after lignocaine injection by 58 +/- 6% and ATP tended to rise even though systolic and diastolic pressure did not change significantly. In group II neither CP nor ATP changed significantly, but systolic and diastolic blood pressure decreased significantly. 4. Repeat lignocaine injections were given over a wider dosage range (0.5-4.0 mg/kg) to determine dose-response for lignocaine versus coronary blood flow. Coronary blood flow increased and per cent wall thickening decreased as doses of lignocaine were increased. 5. It was concluded that rapid intravenous lignocaine injection appeared to cause a dose-dependent coronary dilatation and systolic dysfunction. Pre-treatment with low-dose continuous infusion of lignocaine appeared to result in a decrease in CP and a rise in ATP when compared with no pre-treatment--despite a similar effect on myocardial function and coronary blood flow.

Adenosine Triphosphate↗
PubMed1989

Mouse retroviral sequences acquired by cell lines after passaging through nude mice detected by hybridization of the fms probe pSM3.

The expression of a large RNA transcript, 8.5 to 9.5 kilobases, possibly related to the fms oncogene in mouse, rat, and human tumor cells, has been described in the literature. However, the pSM3 fms probe used to detect this gene transcript contains a significant amount of the pol gene of the Susan McDonough strain of feline sarcoma virus from which it was derived. Using a fms probe which does not contain any viral pol sequences, no such "fms-related" transcripts were detected in cell lines previously reported to express the large transcripts. These cell lines did express a large 9.5-kilobase transcript which hybridized to a probe for murine leukemia virus. Partial sequence analysis of the 9.5-kilobase transcript detected with the pSM3 probe in transformed rat cells indicated sequence homology with AKV murine leukemia virus. Thus, the presence of large RNA transcripts, interpreted by us and others as being related to the oncogene fms, appears to be due to the expression of mouse retroviral sequences which hybridize to the viral pol region contained in the pSM3 fms probe. In the case of rat and human cells, such sequences appear to be acquired after the cells have been passaged in nude mice. These results should serve as a reminder of the important biohazard and data interpretation implications for investigations in which cells transfected with retroviral vector constructs are injected into nude mice, because rescue of the recombinant sequences in these cells could occur following infection by endogenous murine retroviral particles.

Animals↗
PubMed1989

Oculopharyngeal muscular dystrophy in an Irish family.

Victor and his associates coined the term oculopharyngeal muscular dystrophy to describe a clinical syndrome characterised by dysphagia and ptosis. Subsequent authors have traced a large series in French Canadians to a single Quebec isolate and have emphasized that the condition is usually inherited as a dominant trait. In 1974 Fried reported two isolated cases in an Ashkenazi Jewish family of Hungarian extract in whom the condition was recessively inherited. In this paper we report an Irish family from North Cork with typical features of oculopharyngeal muscular dystrophy in whom the inheritance pattern is dominant with incomplete expression. In reporting such cases the ethnic and genetic heterogeneity of oculopharyngeal muscular dystrophy is highlighted. Case Report 1. A 68 year old farmer was admitted for investigation of recurrent chest infections. He complained of a 20 year history of progressive difficulty swallowing, productive cough and impaired vision. On examination he had a gaunt expressionless appearance with bilateral ptosis to mid pupillary level. Both right and left gag reflexes were noted to be reduced and sluggish, and on swallowing fluids were noted to regurgitate through his nostrils. Chest examination revealed the presence of bibasal coarse crepitations suggestive of aspiration. No further physical abnormalities were noted. On investigation, full blood count, urea, and electrolytes, liver function tests, sedimentation rate, thyroid function tests, muscle enzymes (PK, LDH) and electrocardiogram were normal. Chest radiograph confirmed aspiration. Tensilon test was negative. Oesophagoscopy outruled organic obstruction, and confirmed sluggish pharyngeal muscular activity. A clinical diagnosis of oculopharyngeal dystrophy was made on the basis of associated ptosis and dysphagia occurring in the presence of a supportive family history.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Elevated levels of atrial natriuretic peptide during aldosterone escape.

Escape from the sodium-retaining effects of aldosterone (ALDO) is thought to occur as a result of natriuretic compensatory mechanisms triggered by extracellular fluid volume expansion. The purpose of the present study was to determine whether increases in plasma levels of atrial natriuretic peptide occur during ALDO escape in conscious dogs (n = 6) maintained on a fixed sodium intake (60 meq/day). Infusion of ALDO at a rate of 15 micrograms X kg-1 X day-1 for 6 days decreased sodium excretion (UNaV) from 59.1 +/- 4.0 to 36.2 +/- 5.7 meq/day on day 1, and then UNaV gradually returned to control levels by day 5 of ALDO infusion. Net cumulative sodium balance progressively increased during ALDO infusion, reaching a peak value of 88.8 +/- 21.3 meq/day on day 5. Mean arterial pressure increased from 85 +/- 3 to 95 +/- 4 mmHg, and plasma renin activity decreased from 1.32 +/- 0.27 to 0.32 +/- 0.07 ng angiotensin (ANG) I X ml-1 X h-1 during ALDO infusion. Plasma levels of atrial natriuretic peptide averaged 67.5 +/- 8.9 pg/ml during control and increased to a peak value of 120 +/- 18 pg/ml by day 4 of ALDO infusion. Three to four days after ALDO infusion was stopped, plasma levels of atrial natriuretic peptide averaged 46 +/- 5 and 50 +/- 6 pg/ml, respectively. In summary, escape from the sodium-retaining effects of ALDO is associated with significant increases in the circulatory levels of atrial natriuretic peptide.

Aldosterone↗
PubMed1986

Long-term results of low-friction arthroplasty performed in a community hospital, including a radiologic review.

This report is a prospective review of 450 low-friction arthroplasties (LFAs) performed by a single surgeon from 1972 to 1983 in a community hospital. The clinical results show sustained quality of the result over a maximum follow-up period of 11 years. The radiologic review shows a slight increase in the number and size of radiolucent lines with time. Bacteriologic studies confirm that clean-air technology reduces the bacteriologic contamination of the operating room and the wound. Deep infections occurred in 1.6% of cases. The most notable complication was failure to obtain bony union of the osteotomized trochanter in 14% of cases. The revision rate for aseptic loosening of the cup was 0.7% and of the femoral prosthesis 0.0%.

Adult↗
PubMed1982

Thirty-month demonstration project for treatment of self-injurious behavior in severely retarded individuals.

Eighteen severely and profoundly retarded adolescents were treated in a research and demonstration project within a state institution by behavior modification methods for 30 months. Most showed traits of autism, phobias and persistant vulnerability. Restraints had acquired stimulus control. Programming, an aversive event, evoked SIB as avoidance reaction. Effect of pharmacotropic medication was transitory at best. Combination of several behavior modification techniques obtained complete suppression of SIB in 66.6%, partial in 16.7% and none in 16.7%. Non-aversive behavior modification methods, though slow-acting and time-consuming, produced permanent results in 72.7%. Aversive stimulation by remote controlled ESS suppressed SIB instantaneously and made SIB residents accessible to behavior modification and training. In 43%, durability of extinction was limited, despite concomitant intensive full-day behavior modification programs. Extinction was maintained through booster ESS. In two of seven cases ESS lost its aversive qualities. The use of ESS appears justified when non-aversive treatment modalities have failed and life-threatening situations persist.

Adolescent↗