shukoor65/lab-rag-model huggingface dataset:
The heterogeneity of human chorionic gonadotropin (hCG). I. Characterization of peptide heterogeneity in 13 individual preparations of hCG. Peptide variations in the alpha-subunit (molecules starting at alpha 3 and alpha 4) and beta-subunit (missing linkages at beta 44-45 and beta 47-48) of hCG have been reported by several investigators. Studies, however, have been limited to standard hCG preparations (purified from large pools of urine) and other hCG samples from mixed urines. In this study we used chromatographic procedures to purify the total hCG content of 13 individual urines, 6 from patients with pregnancy and 7 from those with trophoblast disease (no hCG-containing fractions were excluded). Then, we examined for the first time the peptide variability among individual samples of hCG. We report 1) that individual hCG preparations have nicks (missing linkages) in the beta-subunit, primarily between residue 47-48 (11 of 13 samples) and, less commonly, at the linkage 44-45 or 46-47 (3 of 13 samples); 2) the extent of nicking varies greatly between individual preparations (range, 0-100% of molecules); 3) varying alpha-subunit N-terminal heterogeneity (N-terminus starting at alpha 3 or alpha 4) was also present (range, 0-28% of molecules), but was confined to preparations from individuals with trophoblast disease (6 of 7 samples from trophoblast disease urine, 0 of 6 from pregnancy urine); 4) hCG missing the beta-subunit C-terminal region was also detected (2 of 13 hCG preparations); and 5) 1 of 13 preparations was nicked on the hCG alpha-subunit, between residues 70 and 71. Thus, 12 of 13 individual hCG samples demonstrated at least 1 of 4 different forms of peptide heterogeneity. We conclude that individual hCG samples vary widely in the type and extent of peptide heterogeneity, an observation that is not appreciated when pools of hCG are studied.
Role of cardiac ATP-regulated potassium channels in differential responses of endocardial and epicardial cells to ischemia. Epicardial cells are more susceptible to the electrophysiological effects of ischemia than are endocardial cells. To explore the ionic basis for the differential electrophysiological responses to ischemia at the two sites, we used patch-clamp techniques to study the effects of ATP depletion on action potential duration and the ability of ATP-regulated K+ channels in single cells isolated from feline left ventricular endocardial and epicardial surfaces. During ATP depletion by treatment with 1 mM cyanide (CN-), shortening of action potential durations was significantly greater in epicardial cells than in endocardial cells. Thirty minutes after initiating exposure to 1 mM CN-, action potential duration at 90% repolarization was reduced to 0.70 +/- 0.12 of the control value for endocardial cells versus 0.39 +/- 0.18 for epicardial cells (p less than 0.01), and action potential duration at 20% repolarization was reduced to 0.72 +/- 0.13 for endocardial cells versus 0.12 +/- 0.09 for epicardial cells (p less than 0.01). In both endocardial and epicardial cells, the shortening of action potential by CN- treatment was partially reversed by 0.3 microM glibenclamide; the magnitude of reversal, however, was much greater in epicardial cells. After exposure to 1 mM CN-, the activity of ATP-regulated K+ channels in cell-attached membrane patches was significantly greater in epicardial cells than in endocardial cells. To study the dose-response relation between ATP concentration and open-state probability of the channels, intracellular surfaces of inside-out membrane patches containing ATP-regulated K+ channels were exposed to various concentrations of ATP (10-1,000 microM). The concentration of ATP that produced half-maximal inhibition of the channel was 23.6 +/- 21.9 microM in endocardial cells and 97.6 +/- 48.1 microM in epicardial cells (p less than 0.01). These data indicate that ATP-regulated K+ channels are activated by a smaller reduction in intracellular ATP in epicardial cells than in endocardial cells. The differential ATP sensitivity of ATP-regulated K+ channels in endocardial and epicardial cells may be responsible for the differential shortening in action potentials during ischemia at the two sites.
Carcinoma of the esophagus: CT vs MR imaging in determining resectability. MR imaging and CT were performed prospectively in 35 patients with esophageal carcinoma to determine the resectability of the primary tumors, because at our institution patients with resectable tumors have surgery regardless of the presence of distant metastases. Tumors with evidence of aortic or tracheobronchial invasion on MR or CT were considered to be unresectable. Tracheobronchial invasion was diagnosed when the tumor extended into the lumen of the airway, and aortic invasion was diagnosed when the triangular fat space between the esophagus, aorta, and spine adjacent to the primary tumor was obliterated. Two patients were excluded because of suboptimal MR images produced by motion artifacts. Pathologic proof was obtained from either surgery or autopsy in 31 patients. Of these, six patients (19%) had proved unresectable tumors (three aortic invasion and three tracheobronchial invasion). In all six cases, these features were correctly detected with both MR and CT. One patient had false-positive findings on MR and CT. An indeterminate diagnosis was obtained with MR in three patients and with CT in four patients. These incorrect or indeterminate results were all related to the diagnosis of aortic invasion. No patient had a false-negative result. When indeterminate diagnoses were considered false-positive, sensitivity, specificity, and accuracy for resectability were 100%, 84%, and 87%, respectively, for MR and 100%, 80%, and 84%, respectively, for CT. We conclude that MR and CT have nearly the same accuracy in predicting resectability of tumors in patients with esophageal carcinoma.
Diverticulitis of the duodenum: clinical and radiological manifestations of seven cases. Seven patients with duodenal diverticulitis were evaluated by computed tomography (CT) and various other abdominal imaging techniques. The series included four men and three women who ranged in age from 47 to 84 yr (mean: 65 yr). They had presented with epigastric or periumbilical pain, low-grade fever, leukocytosis, and loss of appetite and weight due to postprandial cramps or vomiting. In each instance, the abdominal CT examination proved crucial in the diagnosis of duodenal diverticulitis, with contained perforation or inflammatory changes involving the adjacent structures. Five patients underwent laparotomy while two others were treated conservatively with antibiotics and/or percutaneous drainage of peridiverticular abscess. The clinical and radiological features of this uncommon entity are herein described, along with a brief review of the medical literature regarding the current approach to its diagnosis and management.
Cryotherapy for cutaneous Kaposi's sarcoma (KS) associated with acquired immune deficiency syndrome (AIDS): a phase II trial. To assess the response and toxicity of liquid nitrogen cryotherapy for cutaneous lesions of Kaposi's sarcoma (KS) associated with AIDS, we evaluated 20 subjects with biopsy-proven KS in a phase II clinical trial. Subjects had two to four cutaneous KS indicator lesions treated with liquid nitrogen cyrotherapy. Treatment was repeated at 3 week intervals, allowing adequate healing time. On average, subjects received three treatments per lesion with a mean follow-up time of 11 weeks (range of 6-25 weeks). One treatment consisted of two freeze-thaw cycles, with thaw times ranging from 11 to 60 s per cycle. A complete response was observed in 80% of treated KS lesions and lasted a minimum of 6 weeks following the completion of therapy. Greater than 50% cosmetic improvement of KS was observed. Histopathology of treated lesions correlated poorly with cosmetic improvement. Response was not predicted by tolerance to zidovudine therapy, CD4+ cell count, presence of B symptoms, or previous chemotherapy. Subjects without prior history of opportunistic infection (OI) were more likely to have a better response than those with a prior history of OI. Subjects tolerated cryotherapy well. Blistering occurred frequently, but local pain was limited and relieved by acetaminophen. Secondary infection did not occur. Based on this study, we recommend cryotherapy to subjects with cutaneous KS lesions. Liquid nitrogen cryotherapy is easily applied as a primary therapy, and may also have a role in the treatment of cutaneous KS lesions that respond slowly or show incomplete cosmetic improvement with systemic therapies.
Clinical risk factors for Alzheimer's disease: a population-based case-control study. Using information on clinical risk factors provided through the medical record linkage system of the Rochester Epidemiology Project, we conducted a population-based case-control study of Alzheimer's disease (AD). During the period 1960 to 1974, we identified 415 newly diagnosed cases of AD among residents of Rochester, Minnesota, and matched one community control to each case based on age, sex, and duration of community medical record. We estimated odds ratios using conditional logistic regression for several potential clinical risk factors of AD. Among more than 20 clinical risk factors that were evaluated, the only statistically significant findings were for episodic depression, personality disorder, and hypertension.
Increasing incidence of hypertrophic pyloric stenosis. The incidence of pyloric stenosis in the Mersey region rose from 1.54/1000 births in 1976-8 to 2.22/1000 births in 1986-8. Reliance on ultrasonography for diagnosis in the 1980s resulted in fewer 'tumours' being felt; diagnostic delay was not shortened overall but serial ultrasonography showed evolving lesions in six patients. Clinical examination and selective use of ultrasonography is advocated.
Blunt abdominal trauma resulting in intestinal obstruction: when to operate? The overall approach to blunt abdominal trauma resulting in hematoma and intestinal obstruction has been variable and controversial. Recent reports recommend conservative nonoperative management. We reviewed six cases of duodenal and jejunal hematomas resulting from blunt trauma of which five resolved with nasogastric decompression and parenteral nutrition. The average hospital stay was 16 days (10-23 days), and total parenteral nutrition days were 9 days (4-16 days). Upper gastrointestinal series (UGI) demonstrated partial bowel obstruction in all five cases. In contrast, the sixth case was a restrained passenger who had evidence of complete bowel obstruction on UGI series, which failed to resolve after 18 days of conservative management. Laparotomy revealed jejunal and colonic strictures with fibrosis, which were successfully resected. We recommend that based on radiologic documentation of persistent high-grade obstruction, as well as the clinical course, patients whose obstructions do not resolve by 10 to 14 days ought to be further investigated and operative intervention considered. This approach may facilitate an earlier diagnosis of complications, reduce length of hospitalization and days on parenteral nutrition, as well as to expedite the proper management.
Cold cerebroplegia. A new technique of cerebral protection during operations on the transverse aortic arch. Profound hypothermia associated with circulatory arrest is the commonest method of cerebral protection during operations on the aortic arch. This technique allows a limited time to perform the aortic repair, however. It also necessitates prolonged cardiopulmonary bypass to rewarm the patient. This may be the cause of coagulation disorders or infection. Selective perfusion of the carotid arteries can also be used. When the perfusion is derived from the main arterial line, however, the repair of the aorta requires that the vessel be crossclamped, and cannot be performed in an "open, bloodless" manner. To avoid the disadvantages of both techniques, we have developed a new technique of cerebral protection. After a regular cardiopulmonary bypass has been established, the carotid arteries are cannulated and perfused with blood cooled at 6 degrees to 12 degrees C, through a separate heat exchanger, while the core temperature is maintained at moderate hypothermia (25 degrees to 28 degrees C, rectal). To perform the "open" distal repair, the cardiopulmonary bypass is discontinued while the carotid perfusion is maintained (250 to 350 ml/min). When the distal repair is completed, cardiopulmonary bypass is resumed and the carotid perfusion is discontinued. Between 1984 and June 1989, 54 patients (mean age 55 years) were operated on with this method (45 elective operations, 9 emergency procedures). Mean duration of cardiopulmonary bypass was 121 minutes (65 to 248), and mean duration of circulatory arrest was 22 minutes (10 to 51). The electroencephalogram, routinely recorded, showed return of the cerebral activity after a mean time of 12 minutes and normal activity after a mean time of 66 minutes. There was no intraoperative death. Hospital mortality rate was 13% (7/54). One death was related to neurologic disorders. All patients but one awakened normally within 8 hours after operation. Two patients (4.3%) experienced a transient neurologic episode (lateral hemianopia) 9 and 11 days postoperatively. There was no hemorrhagic complication (24-hour average blood loss: 840 +/- 540 ml). In our experience the technique of "cold cerebroplegia" has been demonstrated to provide excellent cerebral protection. It requires no prolonged cardiopulmonary bypass and does not limit the time necessary to perform the aortic repair. It may be considered as a safe alternative to profound hypothermia associated with circulatory arrest.
Lectin-reactive patterns of markedly elevated serum alpha-fetoprotein in patients with chronic active hepatitis. Four cases of chronic hepatitis associated with high serum levels of alpha-fetoprotein (AFP) without hepatocellular carcinoma are reported. All showed transient elevations of serum AFP, with peak levels of 13,500, 8,000, 4,450, and 3,000 ng/ml shortly after aggravation resulting from liver function tests. Liver biopsies revealed severe parenchymal damage in all the cases with piece-meal necrosis, bridging necrosis or bridging fibrosis. In two of four cases, there was a lobular distortion. AFP stain by an immunoperoxidase method showed a positive result in surviving hepatocytes. Lectin affinity electrophoresis of AFP in the four cases, together with an additional 12 patients with chronic hepatitis and cirrhosis and 44 patients with hepatocellular carcinoma, all having AFP levels above 1,000 ng/ml, revealed that the chronic hepatitis patients had a benign pattern of AFP bands, in contrast with the pattern of hepatocellular carcinoma with increased proportions of lentil lectin-reactive AFP-L3 and/or erythroagglutinating phytohemagglutinin-reactive AFP-P4, indicating that the analysis of lectin reactivity of AFP has a great value in differentiating the benign and malignant conditions with increased serum levels of AFP above 1,000 ng/ml.
Effect of ST segment measurement point on performance of standard and heart rate-adjusted ST segment criteria for the identification of coronary artery disease BACKGROUND. Recent reports critical of the performance of heart rate-adjusted indexes of ST depression during exercise electrocardiography have used J-point rather than ST segment measurements. However, no standard exists for the optimal time after the J-point at which to measure ST segment deviation. METHODS AND RESULTS. To assess the effect of ST segment measurement position on performance of standard exercise electrocardiographic criteria, the delta ST segment/heart rate (delta ST/HR) index, and the ST segment/heart rate (ST/HR) slope for the detection of coronary artery disease, the exercise electrocardiograms of 50 clinically normal subjects and 80 patients with known or likely coronary disease were analyzed using ST depression measured at both the J-point and at 60 msec after the J-point (J + 60). A positive exercise electrocardiogram by standard criteria, defined as 0.1 mV or more of additional horizontal or downsloping ST depression at end exercise, had a specificity of 96% when ST depression was measured at either the J-point or J + 60. There was no difference in sensitivity of standard electrocardiographic criteria at J + 60 and J point (both 59%, p = NS). However, at matched specificity of 96%, the delta ST/HR index and ST/HR slope calculated using ST depression at J + 60 were significantly more sensitive (90% and 93%) than when calculated using J-point depression (64% and 61%, each p less than 0.001). Comparison of areas under respective receiver operating characteristic curves confirmed the superior performance of J + 60 as opposed to J-point measurements for both the delta ST/HR index (0.98 versus 0.89, p = 0.006) and the ST/HR slope (0.96 versus 0.87, p = 0.007) and also demonstrated modestly improved overall test performance for standard electrocardiographic criteria using J + 60 measurements (0.88 versus 0.82, p = 0.001). CONCLUSIONS. Use of J-point measurements significantly degrades performance of heart rate-adjusted indexes of ST depression but has less effect on standard criteria.
Psychosis and physical aggression in probable Alzheimer's disease. OBJECTIVE: The purpose of this study was to determine the frequency and type of psychotic symptoms in patients with probable Alzheimer's disease and to test whether there is a relationship between specific psychotic symptoms and episodes of physical aggression. METHOD: From 209 patients with possible or probable Alzheimer's disease who had been assessed in a research clinic every 6 months for up to 4.5 years, 181 subjects with probable Alzheimer's disease were selected for study. On the basis of the summary note for each visit in the patients' charts, the presence of delusions, hallucinations, misidentifications, and episodes of physical aggression was determined. Data regarding psychotic symptoms and aggression were available for 170 and 169 subjects, respectively. RESULTS: Delusions had been reported for 74 (43.5%) of the patients and were the most frequent psychotic symptom; persecutory delusions were the most common type. Physical aggression had been noted for 50 (29.6%) of the patients. Delusions and misidentifications frequently preceded and were significantly associated with episodes of physical aggression. The presence of delusions was a significant predictor of physical aggression but accounted for only 3.5% of the variance. CONCLUSIONS: This study suggests that delusions are a risk factor for physical aggression in patients with probable Alzheimer's disease who have moderate to severe cognitive impairment. As delusions accounted for only a small percentage of the variance, further research is needed to identify other variables that may be significant predictors of physical aggression in this population.
Management of complicated fractures involving the orbits and nasoethmoid complex in young children. This article presents some ideas and techniques for surgical reduction of complicated orbit and nasoethmoid complex fractures in young children. Operative techniques for surgical exposure and fracture reduction and fixation have evolved from standard facial incisions and wire fixation to complete exposure of the cranium and orbits via a bicoronal scalp flap, application of rigid plating techniques, and use of cranial bone grafts when necessary. This evolution of surgical techniques has been accompanied by an overall improvement in cosmetic and functional results.
Postmenopausal estrogen therapy and cardiovascular disease. Ten-year follow-up from the nurses' health study BACKGROUND. The effect of postmenopausal estrogen therapy on the risk of cardiovascular disease remains controversial. Our 1985 report in the Journal, based on four years of follow-up, suggested that estrogen therapy reduced the risk of coronary heart disease, but a report published simultaneously from the Framingham Study suggested that the risk was increased. In addition, studies of the effect of estrogens on stroke have yielded conflicting results. METHODS. We followed 48,470 postmenopausal women, 30 to 63 years old, who were participants in the Nurses' Health Study, and who did not have a history of cancer or cardiovascular disease at base line. During up to 10 years of follow-up (337,854 person-years), we documented 224 strokes, 405 cases of major coronary disease (nonfatal myocardial infarctions or deaths from coronary causes), and 1263 deaths from all causes. RESULTS. After adjustment for age and other risk factors, the overall relative risk of major coronary disease in women currently taking estrogen was 0.56 (95 percent confidence interval, 0.40 to 0.80); the risk was significantly reduced among women with either natural or surgical menopause. We observed no effect of the duration of estrogen use independent of age. The findings were similar in analyses limited to women who had recently visited their physicians (relative risk, 0.45; 95 percent confidence interval, 0.31 to 0.66) and in a low-risk group that excluded women reporting current cigarette smoking, diabetes, hypertension, hypercholesterolemia, or a Quetelet index above the 90th percentile (relative risk, 0.53; 95 percent confidence interval, 0.31 to 0.91). The relative risk for current and former users of estrogen as compared with those who had never used it was 0.89 (95 percent confidence interval, 0.78 to 1.00) for total mortality and 0.72 (95 percent confidence interval, 0.55 to 0.95) for mortality from cardiovascular disease. The relative risk of stroke when current users were compared with those who had never used estrogen was 0.97 (95 percent confidence interval, 0.65 to 1.45), with no marked differences according to type of stroke. CONCLUSIONS. Current estrogen use is associated with a reduction in the incidence of coronary heart disease as well as in mortality from cardiovascular disease, but it is not associated with any change in the risk of stroke.
Relationship of echocardiographic, shunt flow, and angiographic size to the stretched diameter of the atrial septal defect. Stretched diameter of the atrial septal defect (ASD), measured by balloon sizing, is generally used as a guide to the selection of the size of the device utilized for transcatheter closure of the ASD. Balloon sizing is a cumbersome procedure and sometimes requires the use of very large size balloon catheters. Several methods of assessment of ASD size, namely, echographic, pulmonary-to-systemic flow ratio (Qp:Qs), and angiographic measures, were undertaken in a group of 16 patients, aged 7 months to 45 years (median, 4.5 years), who were being evaluated for transcatheter closure of ASD; the results were compared with the stretched diameter. Although the echographic size of the ASD (9.9 +/- 4.1 mm, mean +/- SD) is similar (p greater than 0.1) to the angiographic size (7.9 +/- 2.5 mm), it is much smaller (p less than 0.01) than the stretched diameter (16.1 +/- 5.3 mm). When the relationship between various measures of ASD was examined, although the Qp:Qs ratio and angiographic size have a significant (p less than 0.05) correlation with the stretched diameter (r = 0.55 and 0.54, respectively), the echo diameter has the best correlation coefficient, r = 0.82, p less than 0.001. The stretched diameter can be estimated by the equation: 1.05 x echo + 5.49 mm. It is concluded that the echographic diameter is a useful adjunct in the estimation of the stretch ASD diameter, which in turn can be used in the selection of the size of the device for transcatheter occlusion of the ASD.