123rc/medical_text huggingface dataset:
Depression and recovery of right ventricular function after cardiopulmonary bypass. Transient left ventricular dysfunction is commonly described in association with cardiopulmonary bypass (CPB). We evaluated changes in right ventricular (RV) function after elective cardiac surgery in 24 patients with normal preoperative cardiac function. In all, irrespective of distribution of coronary artery disease or use of pharmacologic support, a transient depression of RV systolic function with respect to both preinduction and initial postoperative (Postop) values occurred 262 +/- 116 min post-CPB as represented by a decrease in RV stroke volume index (25.0 +/- 1.7 vs. 33.4 +/- 1.9 ml/m2 Postop) and RV ejection fraction (31.0 +/- 2.2 vs. 45.6 +/- 2.5% Postop), and an increase in RV end-systolic and end-diastolic volume indices. This depression responded readily to pharmacologic therapy within 2 h, resolved within 24 h, and had no adverse consequences in these otherwise healthy patients. Further studies are needed to identify the cause of this phenomenon and its importance in patients with preexisting cardiac dysfunction.
Coronary vasodilation is impaired in both hypertrophied and nonhypertrophied myocardium of patients with hypertrophic cardiomyopathy: a study with nitrogen-13 ammonia and positron emission tomography. To assess regional coronary reserve in hypertrophic cardiomyopathy, regional myocardial blood flow was measured in 23 patients with hypertrophic cardiomyopathy and 12 control subjects by means of nitrogen-13 ammonia and dynamic positron emission tomography. In patients with hypertrophic cardiomyopathy at baseline study, regional myocardial blood flow was 1.14 +/- 0.43 ml/min per g in the hypertrophied (20 +/- 3 mm) interventricular septum and 0.90 +/- 0.35 ml/min per g (p less than 0.05 versus septal flow) in the nonhypertrophied (10 +/- 2 mm) left ventricular free wall. These were not statistically different from the corresponding values in control subjects (1.04 +/- 0.25 and 0.91 +/- 0.21 ml/min per g, respectively, p = NS). After pharmacologically induced coronary vasodilation (dipyridamole, 0.56 mg/kg intravenously over 4 min), regional myocardial blood flow in patients with hypertrophic cardiomyopathy increased significantly less than in control subjects both in the septum (1.63 +/- 0.58 versus 2.99 +/- 1.06 ml/min per g, p less than 0.001) and in the free wall (1.47 +/- 0.58 versus 2.44 +/- 0.82 ml/min per g, p less than 0.001). In addition, patients with hypertrophic cardiomyopathy who had a history of chest pain had more pronounced impairment of coronary vasodilator reserve than did those without a history of chest pain. After dipyridamole, coronary resistance in the septum decreased by 38% in patients without a history of chest pain, but decreased by only 14% in those with such a history (p less than 0.05). Coronary resistance in the free wall decreased by 45% in patients without and by 27% in those with a history of chest pain (p = 0.06).
Clinical experience with the benzodiazepine antagonist flumazenil in suspected benzodiazepine or ethanol poisoning. The clinical efficacy of different doses of the specific benzodiazepine antagonist flumazenil was studied in a total of 72 patients with benzodiazepine or ethanol overdose. In a randomized double-blind study, 18 patients (group 1) and eight patients (group 2) with suspected benzodiazepine overdose received 5 mg (group 1) or 1 mg (group 2) flumazenil or placebo, respectively. The stage of coma, heart rate, blood pressure and respiratory rate were monitored within the following 15 min. If no change in the stage of coma was observed, 5 mg (group 1) or 1 mg (group 2) flumazenil were given, and the stage of coma, heart rate and blood pressure were again monitored. In a similar way, the effect of 5 and 1 mg flumazenil was investigated in 13 patients (group 3) and four patients (group 4) with ethanol intoxication. In an open trial, the clinical efficacy of flumazenil for the diagnosis of benzodiazepine or ethanol overdose was studied in 29 patients (group 5). In all patients, a toxicological screening confirmed benzodiazepine or ethanol overdose. None of the patients receiving placebo showed effects on stage of coma, heart rate, blood pressure or respiratory rate. Patients with benzodiazepine overdose who received 5 mg flumazenil regained consciousness about 1-2 min after the end of injection. The effect of 1 mg flumazenil (group 2) on benzodiazepine-induced coma was less pronounced. In patients with ethanol overdose (group 3), ethanol-induced coma was reversed after 5 mg flumazenil more slowly than in patients of group 1. No effect of flumazenil on ethanol-induced coma was observed in group 4. In group 5, flumazenil proved to be useful for diagnosing benzodiazepine or ethanol intoxication. In one patient with coma due to carbamazepine overdose, flumazenil was also found to be effective. Additionally, a possible analytical interference of flumazenil and its metabolites with the identification of other benzodiazepines by a toxicological screening procedure was studied. Even after an oral dose of 200 mg flumazenil, no interference with immunological benzodiazepine assays (EMIT, TDX, and RIA) was found. A metabolite and an artifact of flumazenil could be identified in urine by gas chromatography/mass spectrometry.
Central venous oxygen saturation: a useful clinical tool in trauma patients. An accurate method of estimating acute blood loss is essential in the evaluation of injured patients. Central venous oxygen (CVO2) saturation has been shown to be a sensitive and reliable correlate of blood loss in an animal model but its clinical validity is unproven. We evaluated 26 consecutive patients with an injury mechanism suggesting blood loss but who were deemed stable after initial evaluation. Vital signs (pulse, blood pressure, pulse pressure, urine output, CVP) and CVO2 saturation were serially measured. Blood loss was estimated by direct intracavitary collection or serial hematocrits and acute transfusion requirements. Despite stable vital signs, ten patients (39%) had CVO2 saturations under 65%. These patients had more serious injuries, significantly larger estimated blood losses, and required more transfusions than those patients with CVO2 saturation greater than 65%. Linear regression analysis demonstrated the superiority of CVO2 saturation to predict blood loss with a p value less than 0.005 relative to any of the normally followed parameters. CVO2 saturation is a reliable and sensitive method for detecting blood loss. It is a useful tool in the evaluation of acutely injured patients.
Contribution of the band 3-ankyrin interaction to erythrocyte membrane mechanical stability. In an effort to evaluate the role of the band 3-ankyrin linkage in maintenance of red blood cell membrane integrity, solution conditions were sought that would selectively dissociate the band 3-ankyrin linkage, leaving other membrane skeletal interactions intact. For this purpose erythrocytes were equilibrated overnight in nutrient-containing buffers at a range of elevated pHs and then examined for changes in mechanical stability and membrane skeletal composition. Band 3 was found to be released from interaction with the membrane skeleton over a pH range (8.4 to 9.5) that was observed to dissociate the band 3-ankyrin interaction in vitro. In contrast, all other membrane skeletal associations appeared to remain intact up to pH 9.3, after which they were also seen to dissociate. Whereas hemolysis of mechanically unstressed cells did not begin until approximately pH 9.3, where the membrane skeletons began to disintegrate, enhanced fragmentation of shear stressed membranes was seen to begin near pH 8, where band 3 dissociation was first observed. Furthermore, the shear-induced fragmentation rate was found to reach a maximum at pH 9.4, ie, where band 3 dissociation was essentially complete. Based on these correlations, we hypothesize that the band 3-ankyrin linkage of the membrane skeleton to the lipid bilayer is essential for red blood cell stability in the face of mechanical distortion but not for cellular integrity in the absence of mechanical stress.
X-linked spinal muscular atrophy (Kennedy's syndrome). A kindred with hypobetalipoproteinemia. Kennedy's syndrome, X-linked adult-onset bulbospinal muscular atrophy, has been described in over 30 families. The characteristic distribution of weakness creates a recognizable syndrome, augmented by frequent findings of testicular atrophy and gynecomastia. Type IV or type II hyperlipoproteinemia has been found in some families. We have studied another family with Kennedy's syndrome, this one with hypobetalipoproteinemia. The diversity of serum patterns suggests that lipoprotein abnormalities are not causally related to either the endocrinopathy or the spinal muscular atrophy. However, gene linkage studies indicate proximity of the gene for Kennedy's syndrome and the gene encoding the androgen receptor, which could explain the combination of a motor neuron disorder and the endocrine abnormalities.
Carboplatin in childhood brain tumors. A Children's Cancer Study Group Phase II trial. Between October 1985 and March 1988, Children's Cancer Study Group institutions entered 95 patients with recurrent brain tumors into a Phase II trial of carboplatin 560 mg/m2 every 4 weeks. Complete or partial responses were observed for one of 19 evaluable children with brainstem glioma, two of 14 with ependymoma, six of 19 with medulloblastoma or central nervous system primitive neuroectodermal tumor (PNET), and none of 15 with high-grade astrocytoma. Of 33 children with medulloblastoma, ependymoma, or central nervous system PNET, five of 12 with no prior cisplatin exposure had responses, and two of 21 with prior cisplatin exposure had responses (P = 0.03). Thirty-four percent of patients had absolute neutrophil count nadirs less than 500/microliters, and 37% had platelet count nadirs less than 25,000/microliters. Sixteen percent had moderate to severe otoxicity, 10% had nausea and vomiting, and none had nephrotoxicity.
Auro-nasopharyngeal polyp and cholesteatoma. We report the association of an auronasopharyngeal polyp arising in a congenitally abnormal middle ear and Eustachian tube. Subsequently, ten years after removal of the polyp and insertion of a ventilation tube, there was recurrence of the polyp in association with cholesteatoma of the middle ear.
Vasodilatory beta-blockers: systemic and regional hemodynamic effects. The systemic and regional hemodynamic alterations in hypertension and of the beta-adrenergic receptor inhibiting agents are reviewed. Hemodynamically, hypertension may be regarded as persistent elevation of arterial pressure associated with increased total peripheral resistance. In early or mild essential hypertension, however, increased total peripheral resistance may not readily be recognized because of the overriding effect of increased cardiac output. Clearly, the hemodynamics of blood pressure control are complex, and the mechanisms of antihypertensive agents must be used appropriately. The early beta-blockers reduced heart rate and cardiac output immediately after intravenous administration without immediately reducing arterial pressure, and calculated total peripheral resistance was increased. With prolonged oral treatment, arterial pressure decreased while maintaining a reduced heart rate and cardiac output. Total peripheral resistance, however, remained elevated. Recent beta-blockers, such as celiprolol, provide an improved physiologic response by instantly reducing arterial pressure and total peripheral resistance without reducing heart rate or cardiac output or expanding intravascular volume.
Calcium metabolic indices, vascular retinopathy, and plasma renin activity in essential hypertension. The interplays between calcium metabolic indices, retinal vascular status, plasma renin activity and blood pressure were examined in 67 patients with untreated essential hypertension. There was an inverse relationship between plasma ionized calcium and blood pressure (P = .002), whereas albumin-modified total serum calcium was directly related to blood pressure (P = .02). The plasma cyclic AMP level (P = .05) and the 24 h urinary excretion of cyclic AMP (P = .03) were also positively associated with blood pressure. Patients with vascular retinopathy had lower plasma ionized calcium concentrations (P = .01) and higher 24 h urinary cyclic AMP excretions (P = .05) than those without such changes, even when the differences in blood pressure, age, sex and body mass index were taken into account in analyses of covariance. Plasma renin activity did not interfere with the relationships between calcium metabolic indices and blood pressure, nor were there any associations between the renin status and the calcium metabolic indices. These findings suggest that a low concentration of plasma ionized calcium is an independent risk factor for vascular disease.
Tracheoplasty for congenital long-segment intrathoracic tracheal stenosis. Congenital long-segment intrathoracic tracheal stenosis (CTS) is a rare life-threatening obstruction in infancy and childhood. From July 1983 to March 1988 six infants aged 14 days to 14 months with CTS were identified. Symptoms ranged from recurrent stridor and wheezing to severe respiratory compromise and hypercarbia. Routine chest x-rays were not diagnostic. Definitive diagnosis was made by bronchoscopy, which showed complete tracheal rings in all patients with severely compromised tracheobronchial lumens. In three patients, pericardium was successfully used for anterior tracheoplasty with one early death due to fulminant sepsis in an infant with undiagnosed sickle cell disease. The other two died late, at 3 and 9 months from problems unrelated to the repair. In three patients a rib graft was used for repair; in one, tracheoplasty was required after earlier repair of tetralogy of Fallot. All are late survivors with no postoperative symptoms. After recognition of CTS, prompt surgery is warranted to avoid the late complications of tracheostomy for long-term ventilatory support. Rigid repair with rib cartilage is preferable to use of pericardium. Proper rib harvesting with intact perichondrium, intraoperative bronchoscopy, oxygenation by cardiopulmonary bypass, and meticulous graft alignment are necessary for successful postoperative outcome.
Duchenne's cardiomyopathy in a canine model: electrocardiographic and echocardiographic studies. Thirteen dogs affected with X-linked Duchenne's muscular dystrophy and 11 female carrier dogs were studied by electrocardiography (ECG) and echocardiography. Twelve of the affected dogs were studied as immature animals and followed at 1 to 6 month intervals until they were 7 to 46 months of age. Compared with control dogs, affected dogs had significantly increased (p less than 0.02) Q/R ratios in ECG leads II, III, aVF, CV6LL (V2) and CV6LU (V4). Carrier dogs had significantly increased (p less than 0.02) Q/R ratios in leads V2 and V4. The Q/R ratio increased in three of six dogs followed up from age 6 months to greater than 2 years. The PR intervals were significantly shorter (p less than 0.02) in affected dogs. Ventricular arrhythmias were identified in four of six mature affected dogs. Two-dimensional echocardiography revealed distinctive hyperechoic lesions in 12 of the 13 affected dogs and in 6 of the 11 carrier dogs. Hyperechoic lesions corresponded to calcified myocardium and surrounding dense connective tissue. This study establishes the dog affected with Duchenne's muscular dystrophy as an animal model of Duchenne's cardiomyopathy and demonstrates that the heart in carrier dogs is affected by the dystrophic process.
Intracranial aneurysms: interventional neurovascular treatment with detachable balloons--results in 215 cases Patients with complex or surgically difficult intracranial aneurysms are being treated with interventional neurovascular techniques. With neuroleptic anesthesia and a transfemoral femoral approach, a silicone micro-balloon can be flow directed through the intracranial circulation, guided directly into the aneurysm, and detached. The aneurysm is thus eliminated from the circulation, and the parent artery is preserved. For broad-based or ectatic aneurysms, test occlusion followed by permanent occlusion of the aneurysm and parent vessel can be performed. Since 1981, 211 patients with 215 aneurysms, including 177 cases involving the anterior and 38 cases involving the posterior circulation, have been treated with this technique. In 127 cases (59.1%), the parent vessel was occluded; in 88 cases (40.9%), primary occlusion of the aneurysm was achieved with preservation of the parent artery. Therapy-related complications included 21 deaths (9.8%) and 16 strokes (7.4%). Follow-up examinations were performed at 1, 3, and 12 months after treatment, and follow-up ranged from 5 months to 9 years. In patients in whom standard surgical therapy fails or for aneurysms in surgically inaccessible anatomic locations, interventional techniques that make use of detachable balloons may be a useful therapeutic alternative.
Duplex scanning of normal or minimally diseased carotid arteries: correlation with arteriography and clinical outcome. This study evaluated the role of duplex scanning in the management of patients with normal or minimally diseases carotid arteries. Carotid duplex scans were interpreted according to previously established criteria and considered normal when pulsed Doppler spectral waveforms showed laminar flow or only minor flow disturbances. Normal flow patterns were noted by duplex scanning in 100 carotid bifurcations of 72 patients who also underwent carotid arteriography. Neurologic symptoms (amaurosis fugax, transient ischemic attack, or stroke) were present in relation to 23 arteries and absent in relation to 77 arteries. On the 23 symptomatic sides arteriography was interpreted as normal in eight, 1% to 15% stenosis in 14, and 16% to 40% stenosis in one. For the 77 asymptomatic sides, arteriography showed normal vessels in 15, 1% to 15% stenosis in 43, and 16% to 40% stenosis in 19. One symptomatic patient was treated by carotid endarterectomy for an irregular 1% to 15% stenosis. None of the asymptomatic lesions were in the range of 80% to 99% stenosis, which would justify endarterectomy for asymptomatic disease. Clinical follow-up for a mean interval of 28 months on 20 of the 22 symptomatic patients not undergoing surgery revealed no strokes and transient recurrent symptoms in two patients. Assuming that the single operation in this study was indicated, duplex scanning correctly identified lesions not requiring carotid endarterectomy in 96% (22/23) of the symptomatic patients. A normal duplex scan also predicted a benign clinical outcome without operation. Duplex scanning can reliably exclude surgically treatable carotid bifurcation lesions in asymptomatic patients, and endarterectomy is rarely indicated in symptomatic patients with normal duplex scan results. This study supports a nonoperative therapeutic approach for most patients with neurologic symptoms and a normal carotid duplex scan on the appropriate side.
Interictal spiking during wakefulness and sleep and the localization of foci in temporal lobe epilepsy. We examined variations in interictal spiking during sleep and wakefulness to assess differences in reliability for localizing epileptic foci. Forty patients were studied prospectively. Spikes were assessed for rates, field, and appearance of new foci. Final localization was determined by surgery, electrocorticography, and seizure onset. Comparison of interictal EEG foci with final localization was made. In 39 patients, slow-wave sleep activated spiking compared with wakefulness. Most patients showed maximal spiking in sleep stages 3 or 4. Restriction of field in rapid eye movement (REM) sleep and wakefulness, and extension of field in slow-wave sleep occurred. New foci appeared in non-rapid eye movement sleep in 53% of patients. Similar but not identical spiking rates, foci, and field distributions were seen in wakefulness and REM sleep. All REM foci were unilateral. Our findings suggest that localization of the primary epileptogenic area is more reliable in REM sleep than in wakefulness, and in wakefulness more than in slow-wave sleep.
Desmopressin in nocturnal enuresis. The effect of intranasal desmopressin on primary nocturnal enuresis was investigated in a study divided into 2 parts in which the first part was a randomized, double-blind, placebo-controlled cross-over study of 52 Finnish school children 5 to 13 years old. A variety of approaches had previously been attempted in most children, including water deprivation, night awakenings, enuresis alarm and imipramine, without success. The patients were randomized to 4 periods of 3 weeks each: 2 periods on placebo and 2 periods on 20 micrograms. desmopressin spray. The entire 12-week treatment period was preceded and followed by control periods (without treatment). The number of dry nights, measured as calculated averages per week, increased significantly (p less than 0.01) from 0.6 dry nights during pre-treatment to 4.3 and 4.6 dry nights per week during the 2 desmopressin treatment periods, respectively. The placebo responses were 2.1 and 2.4 dry nights per week, respectively. The second part of the study was an open dose-finding and drug safety study of a further 3 months in duration. The aim was to evaluate the efficacy and tolerance of 20, 30 and 40 micrograms. doses. All 47 patients who relapsed during the post-treatment period in part 1 were included. During this period 53% of the patients responded fully, 19% were intermediate responders and 28% did not respond. As reported in other studies most patients suffered relapse after treatment. During continued treatment for 3 months at doses between 20 and 40 micrograms. desmopressin was well tolerated, had no effect on body weight or blood pressure and did not cause any adverse reactions.
Effects of chronic administration of a vasopressin antagonist with combined antivasopressor and antiantidiuretic activities in rats with left ventricular dysfunction. The present experiments were designed to study the long-term aquaretic effect of [d(CH2)5-D-Tyr(Et)VAVP], an antagonist to arginine vasopressin (AVP) with combined vascular (V1) and renal (V2) receptor inhibiting properties, in rats with left ventricular dysfunction resulting from myocardial infarction (MI). The continuous intravenous infusion of the AVP antagonist (36 micrograms/12 microliters/day) via osmotic minipumps over 11 days resulted in an increase in urine volume and a decrease in urinary osmolality by approximately 10-fold on the first day, but in subsequent days this response decreased in both the post-MI (n = 7) and normal (n = 6) rats. Nevertheless, the daily urine volume remained significantly higher and the urinary osmolality lower in the post-MI rats than in the normal ones throughout the study (p less than 0.05). In two other groups of post-MI (n = 5) and normal (n = 6) rats, intermittent intraperitoneal injections of the AVP antagonist (100 micrograms/kg) every third day resulted in a profound diuresis that was reproducible by each injection and was again significantly greater in the post-MI rats than in the normal rats (p less than 0.05). The cumulative urinary output over the first 10-day period of each treatment was greater with intermittent injections than with continuous infusion in both the post-MI and normal rats, but the difference was significant only in the post-MI rats (398.82 +/- 12.87 ml vs 309.07 +/- 32.44 ml, intermittent vs continuous, respectively, p less than 0.05), even though the cumulative dose of AVP antagonist given intermittently was only about one third of that given continuously.