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21.
SL Kamholz RJ Brewer G Grijalva J Burack MJ Del Rio M Vaynblatt N Lawson S Squinto WL Fodor AJ Norin 《Canadian Metallurgical Quarterly》1997,21(9):951-955
The lack of sufficient suitable human donor lungs for the many patients requiring pulmonary transplantation as life-saving therapy for end-stage lung diseases has generated extensive interest in cross-species lung transplantation. Ethical concerns and those of animal rights advocates have prompted studies of nonprimate species as potential solid organ donors for humans. This paper provides an overview of some of the laboratory studies of cross-species pulmonary transplantation performed over the past 20 years and focuses, in particular, on more recent work (from our laboratory and others) in the area of porcine-to-primate pulmonary xenotransplantation. 相似文献
22.
CP Gibbs TD Peabody AJ Mundt AG Montag MA Simon 《Canadian Metallurgical Quarterly》1997,79(6):888-897
We reviewed the cases of sixty-two patients who had had a subcutaneous sarcoma to determine the effect of tumor and treatment-related variables on the rates of survival and local recurrence. Fifty-nine (95 per cent) of the patients had had an operation at another hospital before being referred to us. Twenty-nine (47 per cent) of the sixty-two tumors were high-grade, forty-two (68 per cent) were small (five centimeters or less), and thirty (48 per cent) were malignant fibrous histiocytomas. We followed a treatment strategy that consisted of repeat excision with the goal of obtaining wide margins. Excluding thirteen patients who had had a palpable local recurrence at the time of presentation, twenty (49 per cent) of forty-one patients who had had a marginal excision at another hospital had microscopic residual tumor on repeat excision. At a median of fifty-six months after the repeat excision, fifty (81 per cent) of the sixty-two patients had been continuously disease-free, one had no evidence of disease, eight had died of the disease, and three had died of other causes. The five-year rate of disease-free survival was 85 per cent (fifty-three of sixty-two patients). There were three local recurrences, all in patients who had had a marginal resection. No recurrences were noted in patients who had had a wide local excision of the tumor or of the previous operative field. Multivariate analysis revealed that a large tumor (greater than five centimeters), a marginal excision, and adjuvant radiation therapy were associated with a worse prognosis. Excellent rates of survival for patients who have a subcutaneous sarcoma, including those who have a large or high-grade tumor and those who have residual tumor following a previous operation, can be obtained with carefully planned operative treatment alone. We recommend operative excision or repeat excision with wide margins because of the high prevalence of residual tumor. Size is the most important tumor-related factor, and the operative margin is the most important treatment-related factor. The additional value of adjuvant radiation therapy remains unproved. 相似文献
23.
Dialysis dose and malnutrition have a great impact on the clinical out come of chronic hemodialysis patients. The interrelationships between them, however, remain undefined. Thus, we performed a study to determine the effects of increasing the dialysis dose on serum albumin concentrations and mortality in hemodialysis patients. We examined urea kinetic modeling, biochemical nutritional indices, comorbid conditions, patient survival time, and annual mortality rate. Dialysis dose, measured by Kt/V, significantly increased from 1.3 +/- 0.3 in 1987 to 1.5 +/- 0.4 in 1990 and to 1.7 +/- 0.4 in 1993. Serum albumin level also increased from 3.8 +/- 0.4 g/dL in 1987 to 4.0 +/- 0.4 in 1990 and to 1.7 +/- 0.4 in 1993. In 1993, 76% of patients had Kt/V > or = 1.50 compared with 45% in 1990 and 28% in 1987, whereas 82% of patients had a serum albumin level > or 4.0 g/dL in 1993 compared with 58% in 1990 and 29% in 1987. Protein catabolic rate and hematocrit also increased from 1987 to 1993, but not serum cholesterol or triglyceride. The annual mortality rate declined from 16.1% in 1987 to 13.2% in 1990 and to 8.0% in 1993. The decrease in mortality appeared to be unrelated to differences in patient selection or comorbid conditions. Serum albumin levels, hematocrit, Kt/V, and protein catabolic rate were significantly related to patient survival after age, sex, and diabetic status had been adjusted. Furthermore, there was a positive correlation between Kt/Vs and serum albumin concentration (r = 0.216, P < 0.001). Thus it appears that increasing the dose of dialysis improves serum albumin levels and perhaps survival rate in hemodialysis patients as well. 相似文献
24.
The role of a depressor factor, atrial natriuretic peptide, in the development of arterial hypertension in adolescents with pubertal hypothalamic syndrome was studied in 52 patients and 13 healthy males aged 13-24 years. The duration of disease was 2-11 years. Radioimmunological methods were used to measure plasma atrial natriuretic peptide, plasma renin activity, and serum aldosterone. Patients with borderline arterial hypertension were found to have a significant reduction in their atrial natriuretic peptide levels, and this correlated directly with the renin-aldosterone system, demonstrating insufficiency of the depressor system in patients with pubertal hypothalamic syndrome and the involvement of atrial natriuretic peptide in the development of arterial hypertension, along with disturbances in the functional relationship between atrial natriuretic peptide and the renin-aldosterone system. 相似文献
25.
26.
AJ Gelenberg 《Canadian Metallurgical Quarterly》1993,29(1):135-137
In the absence of a systematic monitoring program for drugs newly approved by the Food and Drug Administration (FDA), reports in clinical journals provide a legitimate forum for disseminating information about unexpected pharmacologic events. A journal editor bears the responsibility for publishing educated clinical observations that meet standards of scientific rigor while not giving premature credibility to chance and dubious reports of side effects of new drugs. Often this responsibility involves overcoming the fear of bad publicity and withstanding pressures from pharmaceutical companies to print only positive information about new products. Published preliminary observations may contribute to the problem of product liability, but they also generate testable hypotheses and healthy debate. If hypotheses later prove to be incorrect, they can be refuted by systematic studies and clarified in reviews and editorials. Our goal of effective education will be reached not by self-censorship but by scientific openness. 相似文献
27.
AJ Barsky 《Canadian Metallurgical Quarterly》1997,278(8):673-679
Catecholamines and volume repletion are currently used for the treatment of septic shock. However, the prognosis of patients suffering from this condition is very poor. An overproduction of nitric oxide (NO) seems to be related to the hypotension and tissue damage of endotoxin shock. Thus, treatment with NO synthase inhibitors has been proposed. Using a rat model of septic shock we have studied the effects of noradrenaline or the NO synthase inhibitor, NG-nitro-L-arginine methylester (L-NMMA) on arterial pressure, tissue damage and NO production. Anaesthetized rats treated with Salmonella typhosa showed a decrease in blood pressure accompanied by an increase in the plasma concentration of cytosolic enzymes (transaminases and lactate dehydrogenase, markers of cell disruption) and nitrite plus nitrate (NO2-/NO3-, markers of NO production). A large proportion of these animals (40%) died before the end of the experiment. Co-treatment with noradrenaline resulted in temporary maintenance of arterial pressure followed by a decline, despite the dose being increased progressively. No differences were observed in plasma cytosolic enzymes, NO2-/NO3- or mortality compared with animals treated with lipopolysaccharide (LPS) alone. In contrast, administration of L-NMMA (10 mg kg-1) to septic animals prevented the fall in blood pressure and death caused by endotoxin. This treatment markedly diminished cell disruption, as measured by the plasma levels of necrosis enzymes, and partially, but significantly, reduced the production of NO as assessed by plasma NO2-/NO3-. We conclude that tissue damage in septic shock is related to the overproduction of NO and not exclusively to the hypotension that follows this increased production. Thus, maintenance of blood pressure with catecholamines fails to improve cellular damage. Instead, partial inhibition of NO generation is sufficient to ameliorate the haemodynamic and tissue-damaging effects of septic shock and improves survival in this model of endotoxaemia. 相似文献
28.
We have measured cardiovascular changes associated with insufflation of carbon dioxide and the reverse Trendelenburg position during laparoscopic cholecystectomy, using transoesophageal echocardiography in 13 healthy patients. End-tidal carbon dioxide values increased after insufflation of carbon dioxide, with values significantly (P < 0.05) increased after lateral tilt positioning. Creation of a pneumoperitoneum was associated with increases (P < 0.05) in left ventricular end-systolic wall stress, concomitant with increases (P < 0.01) in peak airway pressure and systemic arterial pressure. In addition, left ventricular end-diastolic area decreased (P < 0.05) after reverse Trendelenburg positioning. Left ventricular ejection fraction was maintained throughout the study. 相似文献
29.
In this study we have investigated the role of CD4+, MHC class II-restricted cytotoxic T lymphocytes (CTLs) in the disease caused by lymphocytic choriomeningitis virus (LCMV) in beta 2-microglobulin deficient (beta 2m-) mice. Intracranial (i.c.) infection with LCMV resulted in death of six out of 11 beta 2m- mice. Mice that survived showed a marked loss in body weight. Death and loss of body weight could be prevented by immunosuppressing the mice with irradiation or cyclosporine prior to i.c. injection of LCMV. This treatment also prevented induction of virus-specific, MHC class II-restricted CTL following peripheral inoculation with LCMV. In vivo depletion of CD4+ cells with antibody also prevented death following i.c. injection whereas in vivo depletion of CD8+ cells had no effect. Disease could be transferred to recipient beta 2m- mice by adoptive transfer of beta 2m- derived immune spleen cells. Transfer of non-immune spleen cells did not result in illness. In vitro treatment of immune spleen cells with anti-CD4 antibody and complement eliminated class II-restricted CTL activity and also prevented mortality of recipients after adoptive transfer. Treatment with anti-CD8 antibody had no effect. We were unable to transfer LCM disease to beta 2m- recipients by adoptive transfer of immune spleen cells from C57BL/6 mice. These results suggest that, unlike normal mice, the pathology of LCM disease in beta 2m- mice is dependent upon virus-specific, CD4+CD8-, MHC class II-restricted T cells. 相似文献
30.
PURPOSE: The etiology of voiding dysfunction was determined in men after a cerebrovascular accident who were at risk for obstructive uropathy to evaluate whether the cause of voiding dysfunction could be predicted by the type (obstructive or irritative) or onset of symptoms. MATERIALS AND METHODS: We evaluated 38 men with complaints of voiding dysfunction following a cerebrovascular accident. All patients were of the age when bladder outlet obstruction secondary to benign prostatic hyperplasia would otherwise be prevalent. After a comprehensive history and physical examination, all patients underwent multichannel urodynamic studies at a medium fill rate (20 to 50 ml. per minute). Findings were classified by the Abrams-Griffiths nomogram as obstruction, no obstruction or equivocal. RESULTS: Mean patient age was 70 years (range 54 to 87). Patients were grouped according to the presenting voiding complaints (purely irritative in 42%, purely obstructive in 34% or mixed in 24%). In 34 patients (89%) the onset of symptoms paralleled the occurrence of the cerebrovascular accident. Detrusor hyperreflexia was noted in 82% of the patients. There was no statistically significant difference in the occurrence of detrusor hyperreflexia among the 3 symptom groups (Fisher's exact test). Pressure-flow analysis clearly showed obstruction in 24 patients (63%), no obstruction in 9 (24%) and equivocal results in 5 (13%) according to the nomogram. There was no statistically significant difference in the incidence of obstruction among the 3 symptom groups (Fisher's exact test). CONCLUSIONS: Presenting symptoms did not predict the urodynamic findings of bladder outlet obstruction or detrusor hyperreflexia. The significant incidence of onset of symptoms after stroke suggests that the cerebrovascular accident induced voiding dysfunction in the face of preexisting bladder outlet obstruction may exacerbate the symptoms of the latter condition or vice versa. 相似文献