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Biomedical subjects

J Wright

Publications and source records attributed to J Wright.

At least 415 records · Page 23Linked to original sources
PubMed1990

Mineralogic parameters related to amosite asbestos-induced fibrosis in humans.

We have previously shown that in the lungs of a group of chrysotile miners and millers, grade of interstitial fibrosis (asbestosis) is directly proportional to tremolite fiber or chrysotile fiber concentration but is inversely proportional to mean fiber length and length-related parameters. To compare the effects of the commercial amphibole asbestos amosite on parenchymal fibrosis, we histologically graded fibrosis in four different sites in the lungs of 20 shipyard and insulation workers with heavy amosite exposure and measured by analytic electron microscopy fiber concentration and size in corresponding portions of lung tissue. Fibrosis grade was found to be strongly positively correlated with amosite concentration and negatively correlated with mean fiber size parameters, including fiber length, width, surface area, and mass. A comparison of our present results with our data on the chrysotile miners and millers showed that the regression lines of fibrosis grade versus concentration for amosite, chrysotile, and tremolite were statistically different. These findings indicate that amosite concentration, like chrysotile and tremolite concentration, is closely and directly related to fibrosis at the local lung level. Furthermore, these observations again raise the possibility that short fibers may be more important than is commonly believed in the genesis of fibrosis in man. Last, the concentration comparison data indicate that, fiber for fiber, amosite is more fibrogenic than is chrysotile or tremolite, and indirectly suggest that tremolite is more fibrogenic than is chrysotile.

Aged↗
PubMed1990

Effects of cigarette smoke dose and time after smoke exposure on uptake of asbestos fibers by rat tracheal epithelial cells.

We have previously shown that exposure of excised rat tracheal segments to cigarette smoke followed by exposure to a solution of amosite asbestos increases uptake of asbestos fibers compared to exposure to air followed by asbestos. To learn more about the mechanism of smoke-enhanced fiber uptake, we evaluated the effects of amount of smoke and time delay between smoke exposure and asbestos exposure on fiber penetration into the epithelium. To determine whether amount of smoke exposure affected this process, we exposed tracheal segments to 1, 3, or 6 puffs of smoke and subsequently to 5 mg/ml amosite asbestos for 1 h. The segments were then maintained in organ culture for up to 7 d. Asbestos uptake was evaluated by counting fibers in the epithelium by light microscopy. Exposure to increasing numbers of puffs of smoke produced a dose-related increase in fiber uptake at 1 d, 3 d, and 7 d after exposure. To determine whether asbestos exposure needed to occur immediately after smoke exposure for enhanced uptake of fibers to occur, we exposed tracheal segments to 6 puffs of smoke and then delayed exposure to asbestos for 0 (immediate exposure), 3, 18, or 48 h. Tracheas were again maintained in organ culture for up to 7 d after asbestos exposure. Delayed exposure to asbestos after 6 puffs of smoke produced an increase in fiber uptake, even with an interval as long as 48 h between smoke and asbestos exposure; however, the absolute magnitude of fiber uptake was less than that seen with immediate postsmoke asbestos exposure. If catalase was added to the asbestos solution, the smoke-enhanced uptake was abolished, no matter what the time delay.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[The psychosocial profile of couples consulting a fertility clinic].

The objective of this study is to draw the psychosocial profile of couples who consult fertility clinics. More specifically, it consists of a) comparing the psychosocial status of subjects who seek fertility consultation with that of normal subjects or individuals at grips with psychological problems; b) determining whether there are profile differences between men and women who seek fertility consultation; and c) assessing whether it is possible to predict the nature of the psychosocial profile of the subjects from various sociodemographic and medical characteristics. The sampling includes 30 couples who are consulting a specialist in a fertility clinic belonging to a Montréal-area hospital. Analysis of results shows that the psychosocial profile of subjects consulting a fertility clinic is midway between that or normal subjects and that of individuals suffering of psychological problems. The psychological status of men and women consulting a fertility clinic is different according to three variables: depression, self-esteem and stress. Finally, multiple regression analysis has allowed the author to identify several medical characteristics linked to the extent of the psychosocial difficulties experienced by the infertile subjects.

Depressive Disorder↗
PubMed1990

The spastic mouse. And the search for an animal model of spasticity in human beings.

An animal model of chronic spasticity would be valuable. There has been little success at producing such a model, however, because there is no frequently occurring natural disease in animals and, after experimental injury, the animals tend to die or recover. Spasticity in animals or humans is one of the many manifestations of an upper motor neuron syndrome; there is no such thing as pure spasticity. Spasticity in animals and humans involves abnormal functions at many levels of the neurologic and muscular systems. Animal models of spasticity may not be directly applicable to human spasticity, because the animal brain is so different from the human brain. Genetically spastic mice are a homogeneous population that have an abnormally functioning neurotransmitter within the central nervous system. This model has been shown to develop abnormalities of muscle growth that ultimately lead to contracture. The spastic mouse shows some promise for investigation of the abnormalities of muscles and joints that occur in spastic humans.

Animals↗
PubMed1990

"Auto-PEEP": incidence, magnitude, and contributing factors.

In patients receiving mechanical ventilation there occasionally occurs an unintentional positive end-expiratory pressure, known as auto-PEEP, a phenomenon that can easily go undetected. Potential adverse effects of auto-PEEP include misleading hemodynamic information, cardiopulmonary morbidity, or both. Our study was designed to evaluate the incidence of auto-PEEP, its magnitude, and factors influencing it in a university hospital. Every patient receiving ventilation was evaluated for controlled ventilation and auto-PEEP in medical and surgical intensive care units during a 3-month period. Expiration was stopped at the instant that the next inspiration would have been delivered. At this moment, when the pressures in the lung and the ventilator circuit had equilibrated, the level of auto-PEEP was systematically measured. Of 57 patients undergoing controlled mechanical ventilation, 27 (47%) had 1 to 6 cm H2O of auto-PEEP. The incidence of auto-PEEP increased significantly when the minute ventilation exceeded 18.4 L/min, the respiratory rate was higher than 27 breaths/min, or the set PEEP was greater than or equal to 10 cm H2O. Therefore, auto-PEEP is the result of several ventilator-related factors. Because auto-PEEP occurred in 47% of the patients in the study, routine monitoring for auto-PEEP in patients receiving controlled ventilation is recommended. Further studies of auto-PEEP and its clinical impact are warranted.

Adult↗
PubMed1990

Total knee arthroplasty with the kinematic prosthesis. Results after five to nine years: a follow-up note.

A review of the results of 192 kinematic total knee replacements five to nine years after the operation showed that the results were still satisfactory. At the time of the review, the ages of the patients ranged from twenty-two to eighty-seven years. About half of the patients had rheumatoid arthritis and the other half, osteoarthrosis. About 90 per cent of the results were rated good or excellent, and the average range of flexion was 109 degrees. Radiolucency was present around 40 per cent of the tibial components, 30 per cent of the femoral components, and 60 per cent of the patellar components, but the lines were thin and not progressive. The complications included loosening of the patellar components in five knees, one fracture of the tibial tray with loosening of the patellar component, one fracture of the patellar component, and one dislocation of the patellar component.

Adult↗
PubMed1990

Metabolic and cardiorespiratory parameters during three consecutive days of exhaustive running.

The purpose of this study was to examine serum metabolites, cardiorespiratory parameters and creatine kinase during running on 3 consecutive days. Thirteen trained marathon runners exercised to exhaustion on a treadmill at 85 +/- 3% VO2max on each day. Expired gases and blood samples were obtained at rest, after 10 and 30 min of exercise and at exhaustion. There were no significant differences over days for glucose, insulin, lactate, free fatty acids, creatine kinase, oxygen uptake, minute ventilation, heart rate, rating of perceived exertion, respiratory exchange ratio or run times. Serum glycerol was elevated (p less than 0.05) both at rest and during exercise on each successive day. The findings suggested that, except for serum glycerol, acute metabolic and cardiorespiratory responses to exhaustive aerobic exercise are not altered by 3 days daily repetition by endurance trained individuals.

Cardiovascular System↗
PubMed1989

The extraction and purification of a peptide from rat insulinoma tissue.

A peptide was extracted and purified from rat insulinoma tissue which, although similar, was not identical to normal rat C peptides. The purity of the peptide, called rat insulinoma peptide (RIP), was investigated using polyacrylamide gel electrophoresis, isoelectric focusing and high-performance liquid chromatography. It appears to contain two peptides similar to each other but differing in their isoelectric points. The peptides as assessed by fast atom bombardment mass spectrometry have molecular masses in the region of 1982 Da, given a chain length of approx. 22 amino-acid residues. Evidence obtained using an established rat C peptides radioimmunoassay suggests that RIP shares a common C-terminus with rat C peptides. The antiserum produced to RIP was used to develop a radioimmunoassay using a tracer prepared by iodinating purified tyrosylated RIP.

Adenoma, Islet Cell↗
PubMed1989

Priming of human neutrophils with N-formyl-methionyl-leucyl-phenylalanine by a calcium-independent, pertussis toxin-insensitive pathway.

Resting neutrophils may be "primed" to augmented effector function, eg, superoxide (O2-) production in the respiratory burst, upon a second stimulation with a variety of soluble agonists including formylated methionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA). At priming concentrations of FMLP (5 x 10(-9) mol/L) that did not initiate O2- generation, two metabolic activities were noted: (1) approximately a threefold increase in the baseline intracellular calcium (Ca++i) level, that was not dependent on extracellular Ca++, and (2) a rapid rise in intracellular pH that was blocked by 5-(N,N-dimethyl) amiloride (DA), that had no effect on the Ca++i response to priming. Furthermore, there were no significant increases in inositol metabolites in cells primed and stimulated with FMLP compared with cells receiving the stimulating dose of FMLP alone and pretreatment with pertussis toxin (PT) (before the addition of the priming -5 x 10(-9) mol/L dose of FMLP), whereas abolishing the response to FMLP during the second stage of stimulation, had (1) no effect on FMLP-primed cells subsequently stimulated with PMA, and (2) only partially ablated the rise in Ca++i initiated with FMLP. That FMLP priming involved distinctive processes to those of the well characterized FMLP-coupled Ca++-dependent activation cascade was shown by the full priming effect attained in a Ca++-free buffer, which did not sustain an O2- response to a second-stage FMLP stimulation, but sustained a primed response to PMA. These data demonstrate that FMLP primes human neutrophils by a Ca++-independent and PT-insensitive pathway, offering a functional model for studying heterogeneous FMLP receptor-coupled reactions.

Calcium↗
PubMed1989

Disturbances of insulin in British Asian and white men surviving myocardial infarction.

OBJECTIVE: To examine the role of insulin as a cardiovascular risk factor in British Asian and white men. DESIGN: Case-controlled study of survivors of first myocardial infarction. SETTING: District general hospital. PATIENTS: Consecutive series of 76 white and 74 Asian men who survived first myocardial infarction compared with 58 white and 61 Asian male controls without coronary artery disease who were randomly sampled from the community. RESULTS: More Asians than white subjects had impaired glucose tolerance or overt diabetes as measured by the two hour glucose tolerance test (23/74 (32%) v 11/76 (15%) (p less than 0.001) among patients; 17/61 (28%) v 3/58 (6%) (p less than 0.001) among controls). Insulin and C peptide concentrations were higher in both patient groups than in respective controls (p less than 0.001) and higher in Asian than in white subjects, irrespective of their glucose tolerance. Triglyceride concentrations were higher in patients than in controls (1.92 (SD 1.05) v 1.43 (0.82) mmol/l among Asian men; 1.65 (0.83) v 1.3 (0.61) mmol/l among white subjects; p less than 0.001). Total cholesterol concentrations were lower in both groups of Asians than in respective white subjects (5.78 (0.99) v 6.22 (1.04) mmol/l (p less than 0.01) among patients; 5.54 (1.01) v 5.65 (1.11) mmol/l (p less than 0.6) among controls). High density lipoprotein cholesterol concentrations were lower in Asian than in white subjects. The ratio of total cholesterol to high density lipoprotein cholesterol was significantly higher (p less than 0.001) in both patient groups (6.69 (1.81) in Asian patients and 6.31 (1.91) in white patients) than in respective controls (5.24 (1.19) and 4.77 (1.43)). Regression analysis identified C peptide concentration and the ratio of total to high density lipoprotein cholesterol as powerful independent predictors of myocardial infarction in Asian and white men. Total cholesterol concentration predicted infarction in white but not in Asian men. CONCLUSIONS: Secretion and hepatic extraction of insulin are high in survivors of myocardial infarction and especially high in British Asians. Tissue resistance to the action of insulin, giving rise to increased pancreatic secretion, may be an important risk factor for coronary artery disease in both ethnic groups and may be partly responsible for the high incidence of diabetes and coronary artery disease in Asian populations.

Asia↗
PubMed1989

Lead levels in whole blood of sheep from different areas of the Nile delta.

The concentration of lead has been determined in samples of whole blood from Osimi and Rahmani sheep grazing near main highways in three areas of the Nile delta region of Egypt. Between 117 and 200 blood samples were collected from each area. The mean values for the blood lead content were 0.062, 0.067 and 0.083 micrograms/ml, and were low in all the locations. The value of 0.083 micrograms/ml obtained for the samples taken from the partly industralised Enshass region was significantly higher than the mean values from the other sites.

Animals↗
PubMed1989

Nonsecretory multiple myeloma in a 26-year-old man with acquired immunodeficiency syndrome, presenting with multiple extramedullary plasmacytomas and osteolytic bone disease.

High grade B-cell lymphoma and leukemia have been well described in patients with the acquired immunodeficiency syndrome (AIDS). Malignant transformation of more differentiated lymphoid cells has not been well described in these patients. We report a 26-year-old man with AIDS-associated multiple myeloma, who had a highly unusual presentation and clinical course. A review of the literature indicates that monoclonal gammopathy in patients seropositive for the human immunodeficiency virus (HIV) is common. Multiple myeloma and extramedullary plasmacytomas, diseases that are extraordinarily rare in young persons, are now being reported in patients with AIDS and should be added to the list of neoplastic diseases now associated with HIV infection.

Acquired Immunodeficiency Syndrome↗