123rc/medical_text huggingface dataset:
Role of visceral afferent mechanisms in functional bowel disorders. This report analyzes the clinical and physiological evidence supporting a role for altered visceral afferent mechanisms in the pathogenesis of two functional bowel syndromes: noncardiac chest pain and the irritable bowel syndrome. Considerable recent evidence indicates that increased contractility is present only in a minority of patients and that hypercontractile episodes are not temporally related to abdominal pain. In contrast, altered sensation and motor reflexes in response to physiological stimuli, such as mechanical distention or acid, is common when appropriately investigated. The vagal and spinal afferent innervation mediates visceral sensation and is involved in multiple reflex loops regulating gastrointestinal effector function, such as motility and secretion. Sensory input can be modulated peripherally at the afferent nerve terminal, at the level of prevertebral ganglia, the spinal cord, and the brainstem. An up-regulation of afferent mechanisms would result both in altered conscious perception of physiological stimuli and in altered motor reflexes. Current evidence is consistent with an alteration in the peripheral functioning of visceral afferents and/or in the central processing of afferent information in the etiology of altered somatovisceral sensation and motor function observed in patients with functional bowel disease.
Intraoperative coronary excimer laser angioplasty: preliminary clinical experience. Diffuse coronary artery atherosclerosis is generally recognized as a deterrent to successful revascularization if it cannot be adequately treated. Mechanical endarterectomy can be useful, but it is not the optimal solution owing to the associated higher incidences of perioperative infarction and mortality. The use of laser energy as an endarterectomy tool appears promising. To investigate the application of excimer laser radiation to intraoperative coronary artery endarterectomy, 15 stenotic lesions in 13 patients were treated with excimer irradiation during coronary artery bypass grafting. Eleven (73%) of the lesions were enlarged by the excimer probe (6 of the successes were in calcified lesions). The 4 arteries not enlarged by the excimer laser all demonstrated calcified lesions. There were 3 perforations and 2 dissections, all but 1 in heavily calcified arteries. The results of this phase 1 safety and efficacy study indicate that excimer irradiation can recanalize most arteries, including total and subtotal occlusions and some calcified lesions. Further evaluation with better delivery systems is needed to determine whether the perforation rate can be reduced.
Biliary tract disease in rats with experimental small bowel bacterial overgrowth. Small bowel bacterial overgrowth, which develops in surgically created jejunal self-filling blind loops, is associated with hepatic injury in susceptible rat strains. The histological findings are portal tract inflammation and bile duct proliferation and destruction. In this study, evidence of injury to the extrahepatic and intrahepatic bile ducts in susceptible and resistant inbred rats with self-filling blind loops was determined by bile flow rates, histological appearance of cross-sections of bile ducts and cholangiography. Lewis and Wistar rats with self-filling blind loops had thickening of the cross-sectional area of the extrahepatic bile ducts compared with controls and nonsusceptible Buffalo rats (p less than 0.001). Daily metronidazole therapy significantly reduced thickening of bile ducts in Lewis and Wistar rats with self-filling blind loops. Bile flow was increased in Lewis and Wistar rats with blind loops compared with controls (p less than 0.05). Cholangiograms of Lewis and Wistar rats with self-filling blind loops demonstrated extrahepatic ductal dilatation and ectasia with irregular, beaded, rapidly tapering and tortuous intrahepatic ducts. Blinded cholangiographical scores of susceptible rat strains with self-filling blind loops were higher (score = 5.9 +/- 2.3) than those of controls (1.2 +/- 0.4), rats with blind loops treated with metronidazole (0.8 +/- 1.3) and nonsusceptible Buffalo rats with blind loops (0.6 +/- 0.9) (p less than 0.01). Biliary histological and cholangiographical abnormalities found in this rat model resemble features of primary sclerosing cholangitis. This animal model will be useful in exploring mechanisms of the association of hepatobiliary inflammation with intestinal injury and investigating potential therapeutic agents.
Ventricular arrhythmias in ischemic heart disease. Ventricular arrhythmias remain the leading cause of death from coronary artery disease. This review summarizes current thinking in several areas relating to the pathophysiology, prognosis, and therapy of ventricular arrhythmias associated with acute and chronic coronary artery disease syndromes. The experimental basis of arrhythmias in the setting of acute myocardial ischemia and chronic myocardial infarction is described, stressing the important pathophysiologic differences between these two conditions. The effects of the autonomic nervous system as a key modulator of ischemic arrhythmogenesis are discussed. Insights, derived from endocardial mapping studies, into the nature of ventricular tachycardia in humans with chronic myocardial infarction are described, including implications for risk stratification and therapy to prevent arrhythmia recurrence. Current therapeutic principles are discussed in the management of ventricular arrhythmias associated with coronary artery disease, including pharmacologic approaches, surgical and catheter ablation, and automatic implantable cardioverting and defibrillating devices.
The effect of continuous drainage of cerebrospinal fluid in patients with subarachnoid hemorrhage: a retrospective analysis of 108 patients. The effects of continuous drainage of cerebrospinal fluid (CSF) on vasospasm and hydrocephalus were analyzed retrospectively in 108 patients with subarachnoid hemorrhage (SAH) who were operated on for ruptured aneurysms within 48 hours of their onset. Ninety-two of these patients underwent a procedure for CSF drainage (cisternal drainage, ventricular drainage, lumbar drainage, or a combination of these). The duration, the total volume, and the average daily volume of CSF drainage were 10.4 +/- 7.0 days (mean +/- SD). 2034 +/- 1566 ml, and 190 +/- 65.3 ml, respectively. Patients with a greater drainage volume at a lower height of drainage in the early period after SAH developed more cerebral infarctions later (P less than 0.025). The relationship between the total volume of CSF removed and shunt-dependent hydrocephalus was determined to be statistically significant (P less than 0.005). Cerebral infarction and hydrocephalus after SAH were also found to be statistically associated (P less than 0.001). Thus, continuous cerebrospinal fluid drainage should not be performed too readily in patients with SAH, because the removal of a large amount of CSF can induce cerebral vasospasm as well as hydrocephalus.
Giant cell versus lymphocytic myocarditis. A comparison of their clinical features and long-term outcomes BACKGROUND. Giant cell myocarditis has rarely been diagnosed premortem, and little is known about its natural history. In addition, no comparative studies with lymphocytic myocarditis exist. METHODS AND RESULTS. The clinical features, serial change in left ventricular fraction (LVEF), and outcomes of all patients with histologically verified myocarditis were retrospectively evaluated. Ten patients (22%) were found to have giant cell myocarditis (group 1), whereas the remaining 36 (78%) had lymphocytic myocarditis (group 2). Age at presentation, gender distribution, duration of symptoms, initial LVEF, and resting hemodynamics did not differ between groups. Ventricular tachycardia was detected in 90% of group 1 patients compared with only 25% of group 2 (p = 0.0007). Atrioventricular block that required pacemaker insertion was also more common in group 1 (60%) than in group 2 (8.3%) (p = 0.001). Left ventricular systolic function declined during follow-up in group 1 patients (LVEF, 0.43 +/- 0.07-0.26 +/- 0.05, p = 0.11) but increased in group 2 patients (LVEF, 0.33 +/- 0.03-0.41 +/- 0.03, p = 0.02). When the net change between initial and final LVEF was assessed, a significant difference was evident (giant cell group, -0.17 +/- 0.06; lymphocytic group, +0.07 +/- 0.03; p = 0.0008). Although a greater proportion of patients in group 1 died or required transplantation (seven of 10 versus 11 of 36, p = 0.03), actuarial survival over 4 years was not different for the giant cell group (50%) than for the lymphocytic group (62%). CONCLUSION. Giant cell myocarditis was more prevalent than previously recognized and highly associated with both ventricular tachycardia and pacemaker requirement. The likelihood of an adverse event, either cardiovascular mortality or cardiac transplantation, was significantly greater for patients with giant cell myocarditis than for those with lymphocytic myocarditis, perhaps because of the progressive decline in left ventricular systolic function that was observed in those with giant cell myocarditis.
Molecular biology of circulatory shock. Part III. Human hepatoblastoma (HepG2) cells demonstrate two patterns of shock-induced gene expression that are independent, exclusive, and prioritized. During shock and resuscitation, parenchymal cells of solid organs are exposed to a rapidly changing microenvironment, which may include a reduced oxygen tension and an increased concentration of certain cytokines including tumor necrosis factor alpha and interleukin-1. In vivo experiments that testedl iver biopsied from pigs undergoing cardiogenic shock and resuscitation demonstrated several patterns of gene expression. To study the independent and additive influences of hypoxia and of cytokines in vitro, human hepatoblastoma (HepG2) cells were perturbed by hypoxia/reoxygenation (H/R), by heat shock, and by the cytokines interleukin-1 and tumor necrosis factor alpha alone and in combination. H/R induces new patterns of protein synthesis and secretion that are indistinguishable from those induced by heat shock and independent of the acute-phase response mediated by the cytokines. The H/R (heat-shock) response has priority over and will extinguish gene expression supported by the cytokines. This previously unrecognized hierarchy of stress gene expression could well form the molecular basis of shock-related cell and organ failure.
Proliferation characteristics of human colorectal carcinomas measured in vivo. The cell proliferation kinetics of 100 human colonic and rectal adenocarcinomas have been studied in vivo by bromodeoxyuridine infusion and multiparameter flow cytometry. A total of 97 patients, three with synchronous tumours, consented to receive a single bolus dose of 250 mg between 2.4 and 16 h before curative or palliative surgery. By this method, the ploidy pattern, the total and aneuploid labelling indices (LI), the S phase duration (Ts) and the potential doubling time (Tpot) can be estimated. Of the tumours 48 were diploid and 52 were aneuploid. The mean and median total LI of 100 tumours were 9.0 per cent (range 0.7-22.2 per cent). The mean aneuploid LI was 12.1 per cent (median 12.0 per cent, range 2.0-25.5 per cent), and was significantly higher than the total LI (P = 0.01). The labelling index alone is not a sufficient indicator of proliferation, because the Ts also varies within and between tumours. The intertumour range of the Ts varied from 4.0 to 28.6 h. The mean was 14.1 h and the median was 13.1 h. The mean Tpot was 5.9 days (median 3.9 days) with a range of 1.7-21.4 days. No correlation was found between any kinetic parameters and the Dukes' classification or histological classification. The correlation between proliferation and prognosis will be established in due course.
Ten-year follow-up of quality of life in patients randomized to receive medical therapy or coronary artery bypass graft surgery. The Coronary Artery Surgery Study (CASS) Quality of life indexes were assessed in 780 patients 10 years after randomization to medical therapy (n = 390) or coronary artery bypass graft surgery (n = 390) in the Coronary Artery Surgery Study. At 10 years, mortality was 21.8% in the medical group and 19.2% in the surgical group (p = NS), and 144 (37%) of the medical group had undergone surgery because of increasing chest pain. At study entry, 22% of medical and surgical patients were angina free; at 1 and 5 years after entry, the frequency of asymptomatic patients was 66% and 63% in the surgical group and 30% and 38% in the medical group. However, by 10 years after entry, the proportion of patients free of angina had fallen to 47% in the surgical group and to 42% in the medical group. Activity limitation and use of beta-blockers and long-acting nitrates were less in the surgical than the medical group at 1 and 5 years after entry but little different from the medical group at 10 years after entry. Throughout follow-up, recreational status, employment status, frequency of heart failure, use of other medications, and hospitalization frequency were similar between the two groups. Thus, indexes of quality of life such as angina relief, increased activity, and reduction in use of antianginal medications initially appear superior in patients with stable manifestations of ischemic heart disease assigned to surgery, but by 10 years after entry, these advantages are much less apparent. Although the observed similarities of the medically and surgically assigned groups at 10 years reflect return of symptoms in the surgical group to some extent, a more important explanation is the performance of late surgery in a large proportion of the medically assigned patients, rendering them asymptomatic.
Liver and pancreas: improved spin-echo T1 contrast by shorter echo time and fat suppression at 1.5 T. T1-weighted spin-echo magnetic resonance (MR) images have had limited soft-tissue contrast at 1.5 T. The authors investigated the effects of echo-time (TE) minimization and fat suppression on MR images of the liver and pancreas. Two sets of MR images were obtained with identical repetition times and other parameters. In 10 subjects with seven liver lesions, images with TEs of 20 and 12 msec were compared. In 18 additional subjects with seven liver lesions and five pancreatic carcinomas, images with identical TEs but with and without fat suppression were compared. Contrast-to-noise ratios (CNRs) were greater with a TE of 12 msec than with a TE of 20 msec for liver versus spleen (7.6 vs 4.9, P = .014) and liver versus lesion (6.9 vs 3.9, P = .031). In patients without fatty liver, CNR for six lesions versus liver was greater (9.5 vs 6.0, P = .014) with fat suppression. CNR between glandular pancreas and cancer was most conspicuous with fat suppression, but fat planes were less distinct. Minimization of TE improves T1-weighted images significantly. Fat suppression also improves CNR, but the disadvantages of fat suppression do not allow elimination of conventional T1-weighted images.
Bradyarrhythmia after heart transplantation. Incidence, time course, and outcome. From June 1980 to April 1989, 72 of 401 (18%) adult recipients of orthotopic heart transplantation developed prolonged (greater than 24 hours) bradyarrhythmias (less than 60 beats/min) within 5 days after transplantation. Junctional bradycardia occurred in 50 (69%) recipients, sinus bradycardia in 18 (25%), and slow ventricular response during atrial fibrillation in four (6%). Fifty-five of 72 (76%) patients had bradyarrhythmias of less than 20 days' duration (less than 7 days, 50 patients; 7-20 days, five patients). Fifty patients returned to sinus rhythm (greater than 60 beats/min) by the time of discharge. Five patients expired within 20 days. Seventeen of 72 (24%) patients had bradyarrhythmia for more than 20 days, which was symptomatic in 11. All 17 patients (junctional bradycardia, 13 patients; sinus bradycardia, four patients) received a permanent pacemaker within 40 days after transplantation. Between 1 and 12 months (mean, 4 +/- 3 months) after pacemaker implantation, 12 patients recovered sinus rhythm (greater than 70 beats/min). The other five patients had intrinsic rates of 32-57 beats/min (mean, 48 +/- 10 beats/min) during 1-9 months (mean, 4 +/- 3 months) of follow-up. The donor ischemic time in bradyarrhythmia patients was 202 +/- 34 minutes, which was significantly longer (p less than 0.01) than the 173 +/- 43 minutes for those patients without bradyarrhythmia. Conclusively, the incidence of posttransplantation bradyarrhythmia is relatively high. It is usually temporary, however, even in patients with a prolonged duration of bradyarrhythmia. A relation appears to exist between donor ischemic time and the incidence of bradyarrhythmia.
Close correlation of intra-abdominal fat accumulation to hypertension in obese women. The relation between intra-abdominal visceral fat accumulation and blood pressure was investigated in 67 obese women (mean body mass index, 33.6 +/- 3.1; average age, 50 +/- 11 years). As an index of intra-abdominal fat accumulation, the ratio of the intra-abdominal visceral fat area to subcutaneous fat area was determined using a computed tomographic section at the level of the umbilicus. When the obese subjects were divided into a hypertensive group and a normotensive group, the ratio of the intra-abdominal visceral fat area to subcutaneous fat area in the hypertensive group was significantly higher (0.53 +/- 0.33 versus 0.29 +/- 0.12, p less than 0.01). Significant correlations between the ratio of intra-abdominal visceral fat area to subcutaneous fat area and systolic blood pressure (r = 0.62, p less than 0.001) and diastolic blood pressure (r = 0.53, p less than 0.001) also were found. However, no significant difference existed in either the body mass index or the waist-to-hip circumference ratio between the hypertensive and normotensive groups. Plasma renin activity, aldosterone, epinephrine, and norepinephrine levels were not significantly different between the two groups. Moreover, the correlation between the ratio of the intra-abdominal visceral fat area to subcutaneous fat area ratio and blood pressure was found independent of age and body mass index by multiple regression analyses. We conclude that intra-abdominal fat accumulation itself may play an important role in the pathogenesis of hypertension in obesity.
Sepsis-related cardiogenic shock. To further define cardiovascular abnormalities in patients with septic shock, serial conventional hemodynamic measurements combined with two-dimensional echocardiographic studies were performed at the bedside in 21 patients admitted for an acute episode of sepsis-related circulatory failure. Measurements obtained during the first hours of hospitalization revealed a group of six patients (group 1) with markedly depressed left ventricular function, as evidenced by a low cardiac index (CI) (2.2 +/- 0.8 L/min.m2), reduced left ventricular ejection fraction (LVEF) (21 +/- 8%), and an increased arterial-venous oxygen content difference. Right ventricular systolic function was also severely depressed. These patients were characterized as having sepsis-related cardiogenic shock secondary to profound myocardial depression, which was reversible within 24 to 48 h with inotropic support. The 15 remaining patients (group 2) exhibited an initially increased CI (4.9 +/- 1.8 L/min.m2), with a low systemic vascular resistance. In group 2, LVEF remained within the normal range despite abnormally low peripheral vascular resistance. This finding would suggest the presence of slight to moderate depression of left ventricular systolic function. All patients in this series had a normal left ventricular end-diastolic volume, whether profound myocardial depression was present or not.
A surgical approach to the cervicothoracic spine. We describe a method for approaching the lower cervical and upper thoracic spine, the brachial plexus and related vessels. The method involves the elevation of the medial corner of the manubrium, the sternoclavicular joint, and the medial half of the clavicle on a pedicle of the sternomastoid muscle. We have used this exposure in 17 cases with few complications and good results. Its successful performance requires high standards of anaesthesia, surgical technique and postoperative care.
Cytogenetic studies in untreated Hodgkin's disease. Very little data have been published on cytogenetic abnormalities in Hodgkin's disease (HD) and their correlation with clinicopathologic features are scanty. We have performed chromosomal analysis of lymph nodes from 60 previously untreated HD patients and obtained analyzable metaphases in 49 patients (82%). Chromosomal abnormalities were found in 33 patients (55%) but only 31 karyotypes could be, at least partially, described. Twenty-nine cases showed numerical abnormalities that involved all chromosomes with the exception of chromosomes 13 and Y, which were gained less frequently and lost more frequently than other chromosomes. Structural abnormalities were found in 30 cases, involving all chromosomes except Y. Chromosomal regions 12p11-13, 13p11-13, 3q26-28, 6q15-16, and 7q31-35 were rearranged in more than 20% of the analyzable cases. No correlation was found between cytogenetic findings and initial characteristics. When compared with diffuse B-cell lymphomas, defects in regions 2p25 (P less than .01), 12p11-13 (P less than .01), 13p11-13 (P less than .01), 14p11 (P less than .01), 15p11-13 (P less than .02), and 20q12-13 (P less than .05) were more frequent in HD. When compared with T-cell lymphomas, only defects in regions 12p12-13 (P less than .01) and 13p11-13 (P less than .01) were more frequent in HD. Failure to obtain analyzable metaphases was correlated with stage IV of the disease (P less than .05) and with a poor survival (P less than .01), but cytogenetic results showed no other correlation with clinical outcome. We conclude that molecular studies in HD should be focused on the short arms of chromosomes 12 and 13. Determination of the clinical significance of cytogenetic findings will require a larger number of patients and a longer follow-up period.
Effects of calcium channel blockade on calcium homeostasis in mild to moderate essential hypertension. Calcium channel blockers may alter parathyroid hormone secretion in vitro, which would alter calcium homeostasis. To determine the chronic effect of calcium channel blockade in vivo, we conducted a randomized, double blind, 16 week study comparing the effects of two pharmacologic antihypertensive agents, the calcium channel blocker diltiazem and the angiotensin-converting enzyme inhibitor captopril on parameters of calcium homeostasis. Both diltiazem and captopril lowered blood pressure to a similar degree. Neither drug produced any significant change in blood levels of total and ionized calcium, magnesium, or phosphorus, which affect the regulation of parathyroid hormone and vitamin D. In addition, at eight or 16 weeks following initiation, neither drug altered the serum levels of parathyroid hormone (PTH) or 1,25-(OH)2-vitamin D3 (1,25-D). Chronic calcium channel blockade with diltiazem does not alter serum parameters of calcium homeostasis and, thus, should not affect bone mineralization.