123rc/medical_text huggingface dataset:
Load dependence of left ventricular diastolic pressure-volume relations during short-term coronary artery occlusion. We evaluated the effect of altered loading conditions on left ventricular (LV) diastolic pressure-volume relations during acute coronary artery occlusion that was produced by inflation of an intracoronary balloon. Open-chest anesthetized dogs (n = 18) were instrumented so that LV pressure (micromanometer) and LV volume (conductance) could be measured without disturbing the pericardium. The effects of brief periods of occlusion (1-2 minutes) were assessed under steady-state conditions before and after dextran infusion with the pericardium present and absent and during vena caval occlusion. Under steady-state conditions before dextran infusion with the pericardium removed, at an LV end-diastolic pressure (EDP) of 8.4 +/- 1.4 mm Hg, occlusion resulted in a rightward shift in the diastolic portion of the LV pressure-volume loop (delta LVEDP, 2.7 +/- 2.3 mm Hg; delta LVEDV, 6.3 +/- 4.7 ml, both p less than 0.05 versus control). After dextran infusion (LVEDP, 20.9 +/- 6.0 mm Hg), occlusion resulted in a rightward and upward shift in the diastolic portion of the LV pressure-volume loop (delta LVEDP, 5.8 +/- 4.4 mm Hg; delta LVEDV, 4.2 +/- 3.0 ml, both p less than 0.05 versus control). At low cardiac volumes before dextran infusion, the intact pericardium did not affect the response to occlusion. By contrast, after dextran infusion in the presence of an intact pericardium, LVEDP significantly increased (delta, 6.4 +/- 3.6 mm Hg, p less than 0.05) but LVDEV did not (delta, 0.7 +/- 1.5 ml, p = NS). There was a parallel upward shift in the diastolic portion of the LV pressure-volume loop that was eliminated by removal of the pericardium. Thus, the change in LV diastolic pressure and volume during occlusion varied and depended on the baseline cardiac volume and presence of the pericardium. Before dextran infusion with the pericardium present and absent, coronary artery occlusion did not alter the LV diastolic chamber stiffness parameter, which was calculated from the diastolic interval of an averaged steady-state beat (0.040 +/- 0.019 versus 0.036 +/- 0.015 mm Hg/ml, p = NS). After dextran infusion with the pericardium present and absent, coronary artery occlusion increased the LV diastolic chamber stiffness parameter (0.057 +/- 0.034 and 0.074 +/- 0.034 mm Hg/ml, both p less than 0.05 versus controls, respectively). Vena caval occlusion eliminated the shifts in the diastolic portion of the LV pressure-volume loop with the pericardium present and absent.(ABSTRACT TRUNCATED AT 400 WORDS).
Coronary artery fistula formation secondary to permanent pacemaker placement. We present the findings in two patients who apparently developed a coronary artery fistula as a complication of an endocardial pacing electrode. This complication may actually be occurring more frequently than recognized because the patient may be asymptomatic or minimally symptomatic and therefore not undergo a coronary angiogram. Awareness of this potentially serious complication is important and stresses the need for proper electrode placement without excess pressure on the tip.
Use of magnetic resonance imaging in the diagnosis of cortical blindness in pregnancy. Magnetic resonance imaging (MRI) may be helpful in the assessment of eclampsia and preeclampsia with central nervous system symptomatology such as cortical blindness. We describe a rare case of complete binocular blindness postpartum with no other neurologic deficits, in which MRI abnormalities were undetected on computed tomography. The better soft-tissue discrimination of MRI may visualize important but subtle lesions which ultimately may help to explain the underlying pathophysiologic mechanism in such cases.
Auras and subclinical seizures: characteristics and prognostic significance. The characteristics and prognostic significance of subclinical seizures and independent auras were studied in 40 patients with partial epilepsy who had long-term electroencephalographic (EEG) monitoring with intracranial electrodes. Focal, restricted subclinical seizures were noted in 23 patients, and 11 patients experienced auras that were accompanied by ictal EEG discharges. Auras and subclinical seizures usually were identical in EEG appearance, but were distributed differently among patients. The subclinical seizures and auras usually had the same origin as complex partial seizures, but did not always reliably indicate complex partial seizure origin. Subclinical seizures and auras were of favorable prognostic significance for patients undergoing temporal lobectomy. A majority (greater than 80%) of individuals with subclinical seizures and auras were free of complex partial seizures after surgery, whereas a minority (29%) of patients without subclinical seizures and auras became free of complex partial seizures.
Factors associated with binocular single vision in microtropia/monofixation syndrome. We reviewed the charts of 398 patients with microtropia/monofixation syndrome to determine what factors influence the level of binocularity attained. Most patients (82%) exhibited some degree of stereoacuity. Patients with a later age at presentation of the initial deviation were more likely to exhibit stereoacuity (p less than 0.001). Patients with smaller initial deviations were also more likely to exhibit stereoacuity (p = 0.016), as were those with smaller manifest deviations on final testing (p less than 0.001). Patients with amblyopia on final testing were less likely to demonstrate stereoacuity (p = 0.0001). Generally, the more intervention required in the form of optical or surgical correction, the poorer the level of binocularity.
Role of oxygen free radicals in ischemic and reperfused myocardium. In recent years there has been considerable interest concerning the role of oxygen radicals in myocardial ischemia and reperfusion injury. The sequential univalent reduction of oxygen gives rise to very reactive intermediate products. Normally, the tissue concentration of these intermediate products of oxygen is limited and the aerobic myocardium survives because of the existence of a delicate balance between the generation of the various oxidants and the maintenance of the antioxidant defense mechanism. Several possible sources have been identified for the production of active oxygen species after ischemia and reperfusion and these sources may be mutually interactive. The ability of scavengers of oxygen free radicals, including vitamin E, to improve mechanical, mitochondrial, and sarcoplasmic reticulum function in animal models of ischemic-reperfusion injury also suggests that oxygen free radicals are partly responsible for myocardial damage in these models, although caution in the interpretation of these data is necessary.
The molecular biology of occlusive stroke in childhood. It is very likely that many of the same factors involved in occlusive disease in the adult are operative in the child. The major difference may be in the factors that damage endothelium in these two age groups and thereby initiate this catastrophe (atherosclerosis versus "other" causes of endothelial changes). Our task in this next decade is the rational exploration of the effects of endothelium-mediated kinins, endothelial secretory products, angiospasm, platelet aggregration, prostaglandins, and lipoproteins on pediatric stroke.
A controlled clinical trial to assess the effect of a calcium channel blocker on the progression of coronary atherosclerosis To determine whether calcium channel blockers influence the progression of coronary atherosclerosis, 383 patients age 65 years or less with 5-75% stenoses in at least four coronary artery segments were selected at random within 1 month of coronary arteriography to participate in double-blind therapy with a placebo or nicardipine 30 mg three times daily. Coronary events (5 deaths, 22 myocardial infarctions, and 28 unstable anginas) occurred in 28 of 192 nicardipine patients and 23 of 191 placebo patients (p = NS). At 24 months coronary arteriography was repeated in 335 patients. Progression, defined as a 10% or more worsening in diameter stenosis, measured quantitatively, was found in 147 of 1,153 lesions (12.7%) in 168 nicardipine patients and in 170 of 1,170 lesions (14.5%) in 167 placebo patients (p = NS). Ninety-two nicardipine patients (55%) and 95 placebo patients (57%) had progression at one or more sites (p = NS). Regression, that is, an improvement by 10% or more in diameter stenosis, was seen in 140 of 2,323 lesions (6.0%) overall, with no significant intergroup difference. Among the 217 patients with 411 stenoses of 20% or less in the first study, such minimal lesions progressed in only 15 of 99 nicardipine patients compared with 32 of 118 placebo patients (15% versus 27%, p = 0.046). In this subgroup, 16 of 178 minimal lesions in nicardipine patients and 38 of 233 minimal lesions in placebo patients progressed (p = 0.038). By stepwise logistic-regression analysis, baseline systolic blood pressure (p = 0.04) and the change in systolic blood pressure between baseline and 6 months (p = 0.002) correlated with progression of minimal lesions. This suggested blood pressure reduction may account for the beneficial action of nicardipine. These results suggested nicardipine has no effect on advanced coronary atherosclerosis but may retard the progression of minimal lesions.
Results of contemporary radical cystectomy for invasive bladder cancer: a clinicopathological study with an emphasis on the inadequacy of the tumor, nodes and metastases classification. We reviewed 261 patients who underwent a radical operation at a single institution as definitive treatment of invasive bladder cancer to evaluate the survival and accuracy of the tumor, nodes and metastasis system in characterizing the prognosis. Between January 1979 and June 1987 the 261 evaluable patients underwent 1-stage radical cystectomy with pelvic node dissection and urinary diversion. No chemotherapy and/or radiation therapy was given before or after the operation. The postoperative mortality rate was 1.8%. The over-all staging error between clinical and pathological stages was as high as 44%. The over-all actuarial 5-year survival rate was 54.5%. The 5-year survival rates were 75% for stage pT1, 63% for stage pT2, 31% for stage pT3 and 21% for stage pT4 disease. A significant difference in the survival (p less than 0.002) was observed in stage pT3 by dividing tumors confined within the bladder wall (pT3a, 50%) from those extending throughout the bladder wall (pT3b, 15%). A careful evaluation of transitional cell involvement of the prostate in stage pT4a cancer led to the identification of 2 different patterns: 1) contiguous when a bladder tumor extended directly into the prostate through the bladder wall and 2) noncontiguous when a bladder tumor and a transitional cell carcinoma of the prostate were found simultaneously. These patterns had completely different (p less than 0.05) survival rates (6 versus 37%). The patients with high grade tumors had a worse prognosis in comparison with those with grades 1 and 2 tumors (41 versus 56%, p less than 0.005). The over-all 5-year survival of patients with positive nodes was 4% in comparison with 60% of those without nodal involvement (p less than 0.001). Despite current optimal surgical treatment, nearly 50% of all patients with invasive bladder cancer continue to die. The need for a modification of the current tumor, nodes and metastasis tumor classification to provide the clinician a more reliable staging system for planning treatment modalities is indeed mandatory.
Surgery or radiation for early cervical cancer. In summary, neither radiation nor surgery is clearly superior. The benefits of surgery include: 1) emotional satisfaction that the tumor has been removed, 2) accuracy of surgical staging, 3) preservation of the ovaries, 4) no secondary uterine cancer (a very uncommon problem), and 5) complications that are more readily correctable. Radiation offers the major advantages of being useful in most patients regardless of age or medical condition and is the choice for large cancers. Because stage IB cervical cancer is a very diverse pathological entity with a number of potential prognostic factors (including cell type, depth of invasion, tumor volume, lymphatic space involvement, and occult lymph node metastases), and because patients present with a number of other conditions (including excess weight, advanced age, prior pelvic surgery or infection, and severe medical illness), we are fortunate to have two good methods for treating cervical cancer. Prospective randomized studies will be necessary in the future to better define specific advantages in the various clinical settings. But, in general, the following have proven most expedient: 1) class I hysterectomy, for microinvasive cancer of 3 mm invasion or less without lymphatic space involvement, 2) modified, extended hysterectomy (class II) and pelvic lymphadenectomy for lesions of 3 mm and lymph vascular space involvement or when the lesion seems to just exceed 3 mm and for very early adenocarcinoma, 3) an extended hysterectomy (class III) and pelvic lymphadenectomy for larger IA2, IB, and IIA lesions that are less than 4 cm, particularly for the pregnant or younger patient, and when ovarian conservation is desired, 4) radiation therapy is used for lesions over 4 cm and for women with severe medical illness making extended hysterectomy too hazardous, 5) combination therapy and chemotherapy are now reserved for study in poor prognosis patients with very large lesions (greater than 6 cm), occult metastases, and unfavorable histologic criteria (Table 2).
Femoral saphenous vein bypass in a newborn. This is believed to be the youngest patient to undergo a saphenous vein bypass for iatrogenic trauma of the right superficial femoral artery. The infant had emergency right heart catheterisation and Rashkind septostomy for severe desaturation due to transposition of the great arteries. During the exposure of the saphenous vein, the superficial femoral artery was accidentally severed at it's origin. An attempt to restore the circulation by end-to-end anastomosis failed and resulted in persistent limb ischemia for over 4 hours. The baby was reoperated upon, the damaged part of the superficial femoral artery was resected and a saphenous vein graft interposed between the common and the distal superficial femoral artery.
Stereotactic radiosurgery of meningiomas. Stereotactic radiosurgery has an expanding role in the management of selected intracranial tumors. In an initial 30-month experience using the 201-source cobalt-60 gamma knife at the University of Pittsburgh, 50 patients with meningiomas were treated. The most frequent site of origin was the skull base. Previously, 36 patients (72%) had undergone at least one craniotomy and four patients (8%) had received fractionated external beam radiation therapy. Stereotactic radiosurgery was the primary treatment modality in 16 patients (32%) with symptomatic tumors demonstrated by neuroimaging. Computer imaging-generated isodose plans (with one to five irradiation isocenters) for single-treatment irradiation gave optimal (greater than or equal to 50% isodose line) coverage in 44 patients (88%). The proximity of cranial nerves or vascular, pituitary, and brain-stem structures to the often convoluted tumor mass was crucial to dose selection. Serial imaging studies were evaluated in all 50 patients. Twenty-four patients were examined between 12 and 36 months after treatment; 13 (54%) showed a reduction in tumor volume while nine (38%) showed no change. Of 26 patients evaluated between 6 and 12 months after treatment, four showed a decrease in tumor size while 22 showed no change. Two patients (both with large tumors that received suboptimal irradiation) had delayed tumor growth outside the radiosurgical treatment volume. The actuarial 2-year tumor growth control rate was 96%. Between 3 and 12 months after radiosurgery, three patients developed delayed neurological deficits that gradually improved, compatible with delayed radiation injury. Although extended follow-up monitoring over many years will be necessary to fully evaluate treatment, to date stereotactic radiosurgery has proved to be a relatively safe and effective therapy for selected patients with symptomatic meningiomas, including those who failed surgical resection. Radiosurgery was an effective primary treatment alternative for those patients whose advanced age, medical condition, or high-risk tumor location mitigated against surgical resection.
Methodologic issues in assessing the quality of life of cancer patients. Although quality of life assessments have been employed successfully in descriptive and evaluative studies in oncology, their use in cancer clinical trials has, to date, been limited. A range of issues have impeded the conduct of clinical trial-based quality of life investigations. These include: the absence of theoretical models to guide the development of quality of life measures; over-reliance on ad hoc approaches to quality of life assessment; and insufficient attention to the practical constraints operating in clinical research settings. Of primary importance is the need to develop multidimensional quality of life instruments that are brief and psychometrically robust. It is suggested that future work on instrument development focus on refining currently available generic or cancer-specific measures, and on developing new diagnostic-specific questionnaire modules. This psychometric work should be guided by appropriate theoretical models of the relationship among health-related quality of life domains. Although it is widely accepted that the patient represents the most appropriate source of quality of life data, it is suggested that efforts also be directed toward improving the validity and reliability of physician-generated assessments of patients' performance status and of treatment toxicities, and toward determining the feasibility of employing family members as proxy raters of the psychologic and social health status of patients who are unwilling or unable to provide such information. Additional attention should be paid to the many logistical problems that arise in clinical trial-based quality of life investigations. In particular, research designs and data collection procedures should be selected that minimize patient, medical staff, and institutional burden.
Further evaluation of radical surgery following radiotherapy for advanced parotid carcinoma. A series of 30 patients who have been treated for advanced carcinoma of the parotid gland using radiotherapy followed by radical surgery is presented. Three patients deteriorated during preoperative radiotherapy and remained unfit for surgery; the remaining 27 underwent radical parotidectomy with block dissection of the neck. Twelve patients received additional radiotherapy after operation. Of those patients undergoing surgery, three have been lost to follow-up, 17 have died and seven remain alive; the period of follow-up ranges from 3 to 133 months. Fourteen patients remained free of recurrent disease at death or when last seen, and six patients developed a local recurrence at a medium period of 10.5 (range 3-36) months after surgery. For all 30 patients, the cumulative proportion surviving for 5 years was 30 per cent.
Guidelines for transfusion support in patients undergoing coronary artery bypass grafting. Transfusion Practices Committee of the American Association of Blood Banks. We have reviewed the impact of evolving issues in coronary artery bypass grafting (CABG) on transfusion support for these patients. Issues include increased awareness of transfusion risks, reappraisal of traditional indicators triggering transfusion, and evolving alternatives to homologous blood transfusion such as autologous blood and pharmacologic therapy. These issues have been prompted by programs, such as the National Institutes of Health Consensus Conferences, to provide physicians with guidelines for appropriate use of blood components. However, evidence suggests that transfusion practice in coronary artery bypass grafting procedures remains variable and does not take into account the results of recently published clinical studies. We have therefore developed guidelines and recommendations for transfusion support in patients undergoing coronary artery bypass grafting. In summary, they are the following. 1. Institutions with coronary artery bypass grafting programs should establish a multidisciplinary approach to use a combination of interventions designed to minimize homologous blood exposure. 2. Prophylactic transfusion of plasma and platelets are of no benefit and therefore carry an unnecessary risk to the patient. 3. Special request products such as designated blood donation from first-degree relatives should not be used because of the risk of transfusion-associated graft versus host disease. 4. For support of intravascular volume, crystalloids or colloids should be used because they do not have the potential to transmit infection.
Aggressive granulomatous lesions in cementless total hip arthroplasty. We describe six patients with aggressive granulomatous lesions around cementless total hip prostheses. Two patients previously had a cemented prosthesis in the same hip. The Lord prosthesis was used in five patients, the PCA in one. Both prostheses were made of chrome-cobalt alloy. Pain on weight-bearing occurred on average 3.2 years after the cementless arthroplasty, and at that time radiography revealed aggressive granulomatosis around the proximal femoral stem and the acetabular component in five of the patients; one had a large solitary granuloma in the proximal femur. Revision was performed on average 4.8 years after the cementless arthroplasty. At that time all granulomas had grown large in size; while waiting for revision operation, two femoral stem components fractured. All the granulomas showed a uniform histopathology, which included histiocytosis; the cause for these lesions was thought to be plastic debris from the acetabular socket.
Cross-national changes in the effects of peptic ulcer disease. OBJECTIVE: To describe and to analyze the changing effects of peptic ulcer disease over time. DESIGN: Variables relating to peptic ulcer disease from 1970-1986 were compared. The variables included rates of mortality, hospitalizations, operations, physician visits, and endoscopies, and the amount of disability-related loss of work and early retirement in six countries (Belgium, England and Wales, the Federal Republic of Germany, The Netherlands, Sweden, and the United States). MEASUREMENTS: Nonparametric epidemiologic time-trend analysis. MAIN RESULTS: The historic, slow, declining trend in mortality and hospitalization rates continued. The rate of operations for peptic ulcer disease exhibited a large, one-time reduction, then returned to a parallel declining trend, but at a lower level. The rate of physician visits declined by 50%. The greatest changes were found in the rate of endoscopy use and in disability-related loss of work and early retirement, where increasing trends were quickly followed by decreasing trends. The elderly, especially women, generally did not share many of these benefits. CONCLUSIONS: The effects of new interventions can be understood more fully by examining several variables in many countries over a long time. Contrary to expectations, the effects of the widespread use of histamine H2 antagonists have been more indirect (affecting work loss and disability retirement more) than direct (affecting high-cost medical service use and mortality less).