shukoor65/lab-rag-model huggingface dataset:
Evaluation of a new weaning index based on ventilatory endurance and the efficiency of gas exchange. We hypothesized that the ventilatory capacity needed to wean from mechanical ventilation (mv) depends on two variables: ventilatory endurance and the efficiency of gas exchange. We also hypothesized that these variables could be assessed from data readily available at the bedside, including tidal volume (VT) on mv and during spontaneous breathing (sb), ventilator peak inspiratory pressure (Ppk), and patient negative inspiratory pressure (NIP). Ventilatory endurance was evaluated using a modified pressure-time index: PTI = TI/Ttot x Pbreath/NIP, where Pbreath = Ppk x VTsb/VTmv. Defining VE40 as the minute ventilation needed to bring PaCO2 to 40 mm Hg, the efficiency of gas exchange was evaluated by calculating VE40/VTsb = (VE x PaCO2)mv/VTsb x 40. Because high levels of inspiratory effort might cause patients to reduce VTsb and thereby compromise CO2 elimination, we devised a weaning index (WI) that combines ventilatory endurance and the efficiency of gas exchange: WI = PTI x (VE40/VTsb). The study population comprised 38 patients with chronic obstructive pulmonary disease, adult respiratory distress syndrome, pneumonia, neuromuscular disease, and miscellaneous other conditions. They had been mechanically ventilated more than 3 days and were considered by clinical criteria to be ready for weaning. Of 46 weaning trials, 19 were successful, 2 were partially successful, and 25 failed. PTI and VE40/VTsb were higher in patients who failed (p less than 0.05), but neither variable alone had sufficient sensitivity or specificity to predict the outcome of weaning trials accurately.
Nephrotoxic potential of Bence Jones proteins BACKGROUND. The renal manifestations of diseases associated with the production of monoclonal light chains--myeloma (cast) nephropathy, light-chain deposition disease, and amyloidosis AL--result from the deposition of certain Bence Jones proteins as tubular casts, basement-membrane precipitates, or fibrils, respectively. For unknown reasons, the severity of the renal manifestations of these diseases varies greatly from patient to patient. We employed an experimental in vivo model to determine the pathologic importance of various Bence Jones proteins. METHODS. Mice were injected intraperitoneally with 300 mg of Bence Jones protein from 40 patients with multiple myeloma or amyloidosis AL and killed 48 hours later. The mouse kidneys were examined by light and electron microscopy, and light-chain deposits were identified immunohistochemically with highly specific antihuman light-chain antiserum. RESULTS. Of the 40 different human Bence Jones proteins studied, 26 were deposited in the mouse kidneys predominantly as tubular casts, basement-membrane precipitates, or crystals; no light-chain deposits were detected in the kidneys of the mice that received the other 14 Bence Jones proteins. Of the 18 patients for whom renal tissue was available for study, the findings in 14 were comparable to those in the mice. Furthermore, the proteins obtained from 22 of the 27 patients whose serum creatinine concentrations equaled or exceeded 168 mumol per liter (1.9 mg per deciliter) were deposited in the mouse kidneys, whereas protein deposition occurred after the injection of proteins from only 4 of the 13 patients with serum creatinine concentrations below 168 mumol per liter. The repeated injection of Bence Jones proteins from two patients who had amyloidosis AL resulted in deposition of the protein in the mouse kidneys as amyloid. CONCLUSIONS. Particular Bence Jones proteins are primarily responsible for producing the distinctive types of protein deposition in renal tissue and the clinical manifestations that occur in patients with light-chain-associated diseases. This experimental model has potential value for the identification of nephrotoxic or amyloidogenic light chains.
Level of axillary involvement by lymph node metastases from breast cancer is not an independent predictor of survival. We examined the relationship of axillary level of lymph node metastases from clinical stage I and II breast cancer to overall survival and disease-free survival rates in 135 patients who underwent complete axillary lymph node dissection to determine if anatomic level of axillary involvement (I vs II vs III) is an independent prognostic factor. All patients underwent either modified radical mastectomy or lumpectomy with axillary dissection and whole breast radiotherapy for breast cancer. Median follow-up was 6.9 years. We found no difference in overall survival or disease-free survival between patients whose highest or only level of axillary involvement was level I compared with patients whose highest or only level was II. Although patients whose highest level of nodal involvement was III had significantly worse overall survival and disease-free survival rates than patients whose highest nodal involvement was I or II, when patients were stratified by the total number of positive nodes (one to three vs four or more), there was no difference in overall survival or disease-free survival rates between levels I, II, and III. These findings indicate that the level of axillary involvement for stage II breast cancer is not of independent prognostic significance.
In situ venous valve construction. A technique of in situ deep venous valve construction based on vein wall intussusception is described. The technique has been used to construct a size-matched, autogenous valve in the femoral vein of the dog. Forty-one valves have been constructed. Immediately after construction, all 41 were patent at ascending phlebography and Harvey's test showed them to be competent. Descending phlebography demonstrated competence in 38 valves. Hydrostatic testing was performed on 27 valves in the vertical position at pressure gradients in the range 0.2-250 cmH2O. Of these, 24 valves were fully competent. Six valves were studied at intervals between 1 and 112 days after construction. All six were competent by Harvey's test and five were competent at descending phlebography. There was no evidence of thrombosis in any valve. This technique may be suitable for replacement of deep venous valves in patients with the calf pump failure syndrome caused by deep venous reflux.
The recognition and control of occupational disease. Occupational diseases account each year in the United States for an estimated 50,000 to 70,000 deaths and 350,000 new cases of illness. Often, however, occupational diseases are not correctly diagnosed, because they mimic diseases due to other causes and because most physicians are not well trained in their recognition. Opportunities for prevention and treatment are therefore lost. The occupational history is the most effective means for proper diagnosis of occupational illness. It should routinely be obtained for every patient. A brief but systematic guide for obtaining an occupational history is presented in this report. Also, approaches are summarized for the recognition and diagnosis of such important occupational diseases as occupational cancer, asbestosis and other respiratory disorders, and occupational neuropsychologic disorders. The management and prevention of occupational diseases depend on reduction of hazardous exposures in the workplace and better education of workers, industrial managers, and physicians. This report outlines a program for the control of occupational disease based on (1) preventing exposures in the workplace, (2) premarket toxicity testing of new chemicals and technologies, and (3) astute clinical diagnosis.
Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators BACKGROUND. Without strong evidence of benefit, the use of carotid endarterectomy for prophylaxis against stroke rose dramatically until the mid-1980s, then declined. Our investigation sought to determine whether carotid endarterectomy reduces the risk of stroke among patients with a recent adverse cerebrovascular event and ipsilateral carotid stenosis. METHODS. We conducted a randomized trial at 50 clinical centers throughout the United States and Canada, in patients in two predetermined strata based on the severity of carotid stenosis--30 to 69 percent and 70 to 99 percent. We report here the results in the 659 patients in the latter stratum, who had had a hemispheric or retinal transient ischemic attack or a nondisabling stroke within the 120 days before entry and had stenosis of 70 to 99 percent in the symptomatic carotid artery. All patients received optimal medical care, including antiplatelet therapy. Those assigned to surgical treatment underwent carotid endarterectomy performed by neurosurgeons or vascular surgeons. All patients were examined by neurologists 1, 3, 6, 9, and 12 months after entry and then every 4 months. End points were assessed by blinded, independent case review. No patient was lost to follow-up. RESULTS. Life-table estimates of the cumulative risk of any ipsilateral stroke at two years were 26 percent in the 331 medical patients and 9 percent in the 328 surgical patients--an absolute risk reduction (+/- SE) 17 +/- 3.5 percent (P less than 0.001). For a major or fatal ipsilateral stroke, the corresponding estimates were 13.1 percent and 2.5 percent--an absolute risk reduction of 10.6 +/- 2.6 percent (P less than 0.001). Carotid endarterectomy was still found to be beneficial when all strokes and deaths were included in the analysis (P less than 0.001). CONCLUSIONS. Carotid endarterectomy is highly beneficial to patients with recent hemispheric and retinal transient ischemic attacks or nondisabling strokes and ipsilateral high-grade stenosis (70 to 99 percent) of the internal carotid artery.
Epidemiologic and clinical aspects of insulin resistance and hyperinsulinemia. Epidemiologic studies have shown that insulin is a risk factor for coronary heart disease (CHD). Clinical studies have also demonstrated positive correlations between insulin and blood pressure, triglycerides, total cholesterol, fibrinogen, and plasminogen activator inhibitor. Moreover, there is an inverse correlation between insulin and high-density lipoprotein (HDL). These studies have provided evidence in support of the biologic plausibility of epidemiologic observations, but they have not clearly established insulin's role in the pathogenesis of human cardiovascular diseases (CVD) such as hypertension. In fact, there is considerable evidence that insulin resistance (abnormal nonoxidative glucose disposal), not hyperinsulinemia, is the primary insulin-related abnormality in human hypertension, and that hyperinsulinemia occurs as a response to insulin resistance. Skeletal muscle appears to be the primary site of insulin resistance in essential hypertension, although other organs, such as the kidneys and liver--key sites for cell and water homeostasis and lipoprotein regulation, respectively--may respond normally to insulin. Adipocytes also appear to be a site of insulin resistance. Thus, the putative interrelationship between hyperinsulinemia and insulin resistance, on the one hand, and with blood pressure and lipoproteins, on the other, is a complex one and may involve organ-specific insulin resistance. Altered cation transport is one of several mechanisms by which insulin resistance might raise blood pressure. The Na+, K(+)-ATPase and Ca(2+)-ATPase pumps are insulin sensitive. Thus, when insulin resistance is present, the activity of these pumps in the smooth muscle of the arterial wall might be reduced. This would lead to an intracellular accumulation of sodium and calcium, thereby sensitizing the vascular wall to pressor substances. Moreover, secondary hyperinsulinemia will occur, and insulin has been shown to stimulate sympathetic nervous system activity and to increase renal tubular absorption of sodium. Insulin is also a growth factor and therefore might have a trophic effect on the vessel wall, one that could initiate and/or sustain hypertension as well as atherosclerosis. Abnormal lipoprotein metabolism is yet another possible explanation for the accelerated atherosclerosis that has been observed in persons with abnormal carbohydrate tolerance and insulin resistance. Hyperinsulinemia and insulin resistance both play a role in the expression of elevated very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels as well as in the depression of HDL levels. Coronary risk reduction has been disappointing when blood pressure has been lowered with treatment regimens based on thiazide diuretics and/or beta blockers. Thiazides and some beta blockers may further impair tissue insulin sensitivity and often cause blood lipoprotein abnormalities.(ABSTRACT TRUNCATED AT 400 WORDS).
The natural history of superficial femoral artery stenoses. Since the natural history of specific superficial femoral artery stenoses is not known, we examined progression rates of superficial femoral artery stenoses in 45 lower extremities found when arteriograms were obtained of 38 patients for symptomatic atherosclerotic disease in the opposite leg or abdomen. These initial superficial femoral artery arteriograms were compared with later arteriograms in 25 limbs, duplex scans in 27 limbs, and both modalities in 7 limbs. After a mean interval of 37 months, most superficial femoral artery stenoses (72%) did not progress. However, 12 superficial femoral artery stenoses progressed (28%; mean follow-up, 37 months, including 7 that occluded (17%). Superficial femoral artery stenoses progressed among patients who complained of symptom progression at a rate faster than that among asymptomatic patients (15.6%/year vs 3%/year; p = 0.006). Superficial femoral artery lesions also progressed more rapidly among patients whose contralateral superficial femoral artery was occluded (10%/year vs 1.6%/year; p = 0.04). By multivariate regression analysis, symptom progression and smoking history were predictive of superficial femoral artery stenosis progression. In the seven patients whose superficial femoral artery stenoses progressed to occlusion, the average rate of stenosis progression was 12%/year (maximum predicted rate, 30% per year by 95% confidence limit). These results indicate that superficial femoral artery stenoses usually progress with synchronous symptomatic deterioration. Other than symptom progression, only cumulative smoking history and contralateral superficial femoral artery occlusion could be associated with superficial femoral artery stenosis progression in this small series.
Knowledge and beliefs about cancer in a socioeconomically disadvantaged population. Americans living in poverty experience a higher incidence of and greater mortality from cancer than the nonpoor. At least 50% of the difference in mortality is believed to be due to delay in diagnosis, although risk-promoting lifestyles and behaviors also contribute to decreased survival. A potential exacerbating factor among the poor is inadequate information and knowledge about cancer and its treatment. Interviews were conducted with 128 cancer patients from a socioeconomically disadvantaged population to assess knowledge of cancer and its treatment and to evaluate care-seeking behaviors. Results indicated that although patients relied primarily on their physicians for information about their disease and treatment, a number of misconceptions regarding cancer existed in this population. Notably, nearly 50% of the patients surveyed either denied or did not know that smoking was related to the development of cancer. Additionally, patients frequently reported inappropriate care-seeking behaviors when asked to respond to a series of common disease-related signs or symptoms. These findings suggest that misinformation and misconceptions regarding cancer and its treatment among patients in this sample may contribute to inappropriate care-seeking behaviors.
Comparative safety, tolerance, and pharmacokinetics of amphotericin B lipid complex and amphotericin B desoxycholate in healthy male volunteers. Amphotericin B lipid complex (ABLC), a lipid complex formulation of amphotericin B, and amphotericin B desoxycholate (AB) were compared for safety, tolerance, and pharmacokinetics in two groups of eight healthy male volunteers. After a 1-mg test dose, study drug was infused at 0.1, 0.25, and 0.5 mg/kg; the 0.5-mg/kg dose was not given to subjects receiving AB. ABLC caused few acute adverse effects except for mild somnolence (drowsiness) in six volunteers. In addition, three of eight ABLC recipient had asymptomatic, transient serum transaminase elevations that resolved spontaneously. The AB recipients experienced more acute side effects, but only one had a mild shaking chill: three of eight also experienced sleepiness. No significant changes in vital signs, electrocardiogram, oximetry, pulmonary function, or clinical status were observed in either group. Due to its increased estimate volume of distribution and estimated clearance. ABLC yielded decreased amphotericin B levels and area under the serum concentration versus time curve relative to AB.
Effects of sleep-induced increases in upper airway resistance on ventilation. To determine the effects of the sleep-induced increases in upper airway resistance on ventilatory output, we studied five subjects who were habitual snorers but otherwise normal while awake (AW) and during non-rapid-eye-movement (NREM) sleep under the following conditions: 1) stage 2, low-resistance sleep (LRS); 2) stage 3-4, high-resistance sleep (HRS) (snoring); 3) with continuous positive airway pressure (CPAP); 4) CPAP + end-tidal CO2 partial pressure (PETCO2) mode isocapnic to LRS; and 5) CPAP + PETCO2 isocapnic to HRS. We measured ventilatory output via pneumotachograph in the nasal mask, PETCO2, esophageal pressure, inspiratory and expiratory resistance (RL,I and RL,E). Changes in PETCO2 were confirmed with PCO2 measurements in arterialized venous blood in all conditions in one subject. During wakefulness, pulmonary resistance (RL) remained constant throughout inspiration, whereas in stage 2 and especially in stage 3-4 NREM sleep, RL rose markedly throughout inspiration. Expired minute ventilation (VE) decreased by 12% in HRS, and PETCO2 increased in LRS (3.3 Torr) and HRS (4.9 Torr). CPAP decreased RL,I to AW levels and increased end-expiratory lung volume 0.25-0.93 liter. Tidal volume (VT) and mean inspiratory flow rate (VT/TI) increased significantly with CPAP. Inspiratory time (TI) shortened, and PETCO2 decreased 3.6 Torr but remained 1.3 Torr above AW. During CPAP (RL,I equal to AW), with PETCO2 returned to the level of LRS, VT/TI and VE were 83 and 52% higher than during LRS alone. Also on CPAP, with PETCO2 made equal to HRS, VT, VT/TI, and VE were 67, 112, and 67% higher than during HRS alone.
Total arthroplasty of the hip after childhood sepsis. Total hip arthroplasty was performed in 45 hips of 44 patients who had pyogenic arthritis of the hip during childhood. The average age of the patients was 36.4 years (range 19 to 50). The interval between active infection and arthroplasty ranged from 11 to 40 years, and average follow-up was 65.4 months (range 58 to 80). Specimens of tissue taken before and during operation gave negative cultures in all hips, and no patient had reactivation of infection. The mean functional rating of the hips was 58 points before operation and 90 at the final review. Complications were seen in 11 cases (24%), loosening of components occurred in six (13%) and one hip had to be revised for acetabular component migration. Acetabular allografts were required in 27 hips (60%). All allografts united but there was partial resorption of the graft in the non-weight-bearing area in all.
Hemorrhagic venous infarction after excision of an arteriovenous malformation: case report. A case of arteriovenous malformation (AVM) in which postoperative hemorrhagic infarction developed, probably because of occlusion of the former draining veins, is reported. The hemorrhage developed in the temporal lobe 3 days after the initial operation and was located in the immediate vicinity of the site of the AVM. The following findings suggest that the postsurgical hemorrhage probably resulted from a venous thrombosis: 1) no evidence of residual AVM; 2) delayed onset of the hemorrhage, inconsistent with the time course of a hemorrhage developing according to the breakthrough theory or with insufficient hemostasis with a high-pressure afterload; 3) good correlation between the location of the hemorrhage and the occlusion of the draining veins; and 4) multifocal hemorrhage affecting both the gray matter and the subcortical white matter. Postoperative hemorrhagic infarction caused by thrombosis in the draining veins is rare, but it should be considered as a distinct postoperative complication after removal of an AVM.
Cell recovery during segmental intestinal perfusion in healthy subjects and patients with Crohn's disease. The recovery of cells arising from small intestinal mucosa alone was studied during continuous perfusion of a closed segment of jejunum. The perfusion technique minimised the contamination of the perfused segment with, for example, proteolytic enzymes from pancreas, allowing recovery of viable cells. The use of hyaluronidase in the perfusion fluid increased the recovery of cells fivefold, the median recovery being 8 x 10(6) cells. The cells were analysed with monoclonal antibodies and flow cytometry. Nearly all cells (98-99%) recovered during perfusion of healthy control subjects and patients with Crohn's disease were epithelial cells. The jejunal cells expressed HLA-DR in similar proportions--around 30%--in patients and control subjects. The ratio between CD4+ and CD8+ lymphocytes was similar (0.2) in control subjects and patients with inactive Crohn's disease but decreased (0.03) in patients with active Crohn's disease in the ileum.
Candidal mediastinitis after surgical repair of esophageal perforation. Candidal mediastinitis, like Boerhaave's syndrome, is uncommon, and both, if treated late or incompletely, frequently result in death. Early recognition and aggressive medical and surgical intervention are the best means to convalescence and cure in both conditions.