123rc/medical_text huggingface dataset:
Protecting the vasculature: an eye toward the future. Although calcium antagonists were originally developed for use in the management of patients with angina pectoris, they are now used in the management of other cardiovascular disorders, including hypertension. More recently, the calcium antagonists have been under investigation for their potential protective role in atherosclerosis. Coupled with these new possibilities for therapeutic use are the development of new, long-acting, tissue-specific calcium antagonists. Amlodipine belongs to this group, and although it is a dihydropyridine-based calcium antagonist, its pharmacologic profile differs from that of other dihydropyridine-based calcium antagonists. Differences include: different pH optimum for receptor binding, different rates of association and dissociation, and differences in allosteric interaction with the diltiazem and verapamil binding sites. Amlodipine, when given orally to rabbits receiving a high-cholesterol diet, reduces atheroma formation. Evidence of its ability to protect the vasculature is provided by its ability to significantly increase (p less than 0.001) survival in stroke-prone hypertensive rats.
Adult open heart surgery in New York State. An analysis of risk factors and hospital mortality rates This study analyzes data from New York State's new Cardiac Surgery Reporting System, which contains information about cardiac preoperative risk factors, postoperative complications, and hospital discharge. The purposes of the study were to determine the set of significant clinical risk factors and to identify cardiac surgical centers most likely to have serious quality-of-care problems. Significant risk factors for in-hospital death were age, gender, ejection fraction, previous myocardial infarction, number of open heart operations in previous admissions, diabetes requiring medication, dialysis dependence, disasters (acute structural defect, renal failure, cardiogenic shock, gunshot), unstable angina, intractable congestive heart failure, left main trunk narrowed more than 90%, and type of operation performed. Four of the 28 hospitals had significantly higher mortality rates than expected, given the risk factors of their patients. Subsequent site visits and medical record reviews confirmed that these facilities had high percentages of quality-of-care problems among cases resulting in mortality.
Effects of age on seizure susceptibility in genetically epilepsy-prone rats (GEPR-9s). To study the effect of age on seizure latency, intensity, reproducibility, and mortality in genetically epilepsy-prone rats of the severe colony (GEPR-9s), 472 seizure-naive rats, ranging in age from 14 to 65 days, received a series of three audiogenic stimulations. Both the percentage of rats having one or more seizures and the percentage of seizures that were stage 9 generally increased with advancing age of the animal at the time of the first stimulation. Mean latency to seizure onset decreased while seizure intensity increased with increasing age of the animal. Reproducibility of seizure stage also increased with advancing age of the animal. The effects of senescence on seizure susceptibility were also investigated in an additional 18 prepubescent rats (25-35 days) who received three audiogenic stimulations and were tested again between the ages of 480 and 540 days with identical testing procedures. No significant changes occurred with either latency to seizure onset or seizure intensity in rats tested during prepubescence and again at senescence. Although GEPR-9s provide an excellent model of inherited seizures, latency to seizure onset, seizure intensity, and seizure reproducibility is dependent on age of the animal. Once established, however, audiogenic-induced seizures persist throughout life.
The child with recurrent solid tumor. A significant percentage of relapse occurs in children with solid tumors despite advances in treatment. This article discusses reasons for failure of primary therapy, evaluation of the relapsed patient, treatment of the relapsed patient, as well as questionable cancer therapies and therapy cessation.
Results of infrainguinal bypass for limb salvage in patients with end-stage renal disease. Limb salvage in patients with end-stage renal disease (ESRD) is complicated by the diffuse, obstructive, calcific arteriopathy that makes anastomotic technique especially critical. Furthermore, decreased resistance to infection and impaired wound healing produced by host-factor deficiencies such as diabetes mellitus, hypoalbuminemia, uremia, and immunosuppression produce additional obstacles to successful limb salvage. This report summarizes our experience with distal arterial bypass procedures in these patients. A total of 32 bypass procedures were performed for limb salvage in 24 patients (17 diabetic) during a period of 5 years. The operative mortality rate was 6%. During the same period, 635 infrainguinal bypass procedures were performed by the in situ technique in patients without ESRD. Primary bypass patency was comparable in both groups at 24 months (92% vs 90%). In the group with ESRD, overall limb salvage was 83% at 2 years. Life-table analysis of bypass patency and limb salvage was thought not to be appropriate in the population with ESRD beyond 2 years because of the increased mortality rate (38%; 9/24) during this interval. It is important that limb salvage was achieved in diabetic patients with ESRD in the presence of extensive foot gangrene or ischemic ulceration. Revascularization should be considered strongly for limb salvage in all patients in this difficult population.
Evaluation of the pharmacokinetics and electrocardiographic effects of intravenous verapamil with intravenous calcium chloride pretreatment in normal subjects. To evaluate the effects of calcium pretreatment on the disposition and electrocardiographic effects of verapamil, 8 healthy male volunteers received treatment in each of 3 phases in a randomized, double-blind, crossover manner. Phase I denoted 10 ml of 0.9% intravenous sodium chloride followed by 10 mg of intravenous verapamil; phase II denoted 10 ml of 10% intravenous calcium chloride followed by 4 ml of 0.9% intravenous sodium chloride; and phase III denoted 10 ml of 10% intravenous calcium chloride followed by 10 mg of intravenous verapamil. Blood samples for the determination of verapamil concentrations were drawn at 5, 10, 15, 20, 30, 45, 60 and 90 minutes, and at 2, 4, 6, 10 and 24 hours. Blood pressure, heart rate and PR intervals were also measured at these times. Pretreatment of verapamil with intravenous calcium did not alter the disposition of intravenous verapamil. Blood pressure was not significantly altered in any treatment phase, although calcium tended to increase mean arterial pressure and verapamil abolished this effect. Calcium had no significant affect on verapamil-induced PR prolongation (maximum percent change in PR interval: phase I = 19 +/- 11%, phase III = 18 +/- 7%; time to maximal prolongation: phase I = 0.38 +/- 0.21 hours, phase III = 0.37 +/- 0.26 hours; and area under the percent change in PR vs time curve: phase I = 15.5 +/- 10, phase III = 21 +/- 9). Verapamil caused a reflex increase in heart rate of similar magnitude in both phases I and III (24 +/- 10% and 21 +/- 7%, respectively).
Experimental nerve root compression. A model of acute, graded compression of the porcine cauda equina and an analysis of neural and vascular anatomy. Nerve root compression has been suggested as one important pathogenetic factor in low-back pain syndromes and sciatica. The underlying pathophysiologic mechanisms are, however, incompletely known, partly because of the lack of experimental data on this topic. In the present study, a model for experimental compression of the porcine sacrococcygeal cauda equina is presented. The model consists of surgical exposure of the cauda equina and compression of the cauda equina toward the ventral aspect of the spinal canal by an inflatable balloon fixed to the spine. This compression system was shown to have a high accuracy in pressure transmission from the balloon to the cauda equina. The gross and microscopic neural anatomy and the vascular anatomy of the porcine cauda equina were analyzed with light microscopic and ink-perfusion techniques. The porcine cauda equina showed a close anatomic resemblance to the human lumbosacral cauda equina. The presented model offers unique possibilities for experimental studies on nerve root compression injury because of the easy surgical exposure and the sufficient length of the nerve roots. In separate studies, this model, along with investigations of solute transport to the nerve tissue and of impulse propagation, has been used to analyze the effects of acute, graded compression on blood flow and edema formation in the cauda equina. The porcine cauda equina would also be particularly suitable for chronic compression studies because any neurologic deficit acquired would be restricted to the tail.
Traumatic rupture of aorta. Diagnosis by Doppler echocardiography. Traumatic rupture of aorta is a serious complication in accidents, mainly road accidents, with a high mortality unless an immediate diagnosis and surgical correction is made. A case of traumatic rupture of the aorta shown in the acute phase by Doppler-echocardiography is reported. This technique can be of great value in the study of patients with thoracic trauma who do not show clear signs of aortic rupture which require urgent aortography.
Schatzki's ring: long-term results following dilation The purpose of this study is to report long-term results of 61 patients with Schatzki's ring who were dilated for relief of dysphagia. The severity of Schatzki's ring was mild in 28 patients (46%), moderate in 26 (43%), severe in 5 (8%), and indeterminate in 2 (3%). Follow-up information was available in 56 of 61 patients (mean, 75 months). During follow-up, 35 patients (63%) developed recurrent dysphagia and required repeated dilations: 19 patients (34%) had one to two dilations, 9 patients (16%) had three to seven dilations, 6 patients (11%) had more than seven dilations; 1 patient underwent surgery for resection of the Schatzki's ring (2%). The mean (range) dilation-free interval was 50.1 months (11.8 to 100 months) in mild cases, 44.5 months (8.9 to 82 months) in moderate cases, and 28.6 months (9 to 76 months) in severe cases. There was no significant correlation between the severity of Schatzki's ring on initial presentation and the subsequent dilation-free interval. Our data indicate that recurrent dysphagia is common among patients with Schatzki's ring after a successful dilation, and that the severity of Schatzki's ring is not a good prognostic indicator of the need for subsequent dilation.
Congenital cystic disease of the seminal vesicle. Thirteen cases of congenital seminal vesicle cysts with pathologic correlation were diagnosed between 1970 and 1988. Twelve of the 13 patients had ipsilateral renal anomalies. Intravenous urography, performed in 11 of the 13 patients, demonstrated associated renal anomalies. Computed tomography, performed in nine of the 13 patients, demonstrated associated renal anomalies and displayed the cystic seminal vesicles. Transabdominal or endorectal ultrasonography, performed in eight patients, allowed characterization of the seminal vesicle masses as cystic. Magnetic resonance imaging, performed in three of the 13 patients, accurately demonstrated dilated ejaculatory ducts into which ectopic ureters inserted. The fluid in the seminal vesicle cysts had an increased signal intensity on T1- and T2-weighted sequences. Seminal vesiculographic study demonstrated anomalous communications with the seminal tract. Cystic disease of the seminal vesicles can be either congenital or acquired; congenital cysts are associated with anomalies of the ipsilateral mesonephric duct.
Role of endothelium in the response to endothelin in hypertension. The relation between endothelin and acetylcholine (ACh) was examined and compared in aortas from Wistar-Kyoto (WKY) rats and from stroke-prone spontaneously hypertensive rats (SHRSP). The relaxation produced by ACh in an endothelin-induced contraction was less in aortas from WKY rats than in those from SHRSP. In aortas from WKY rats but not in those from SHRSP, the contraction produced by endothelin was augmented when the intact aortic rings were treated with methylene blue (10(-5) M). This augmentation was also found in preparations of the WKY rat aortic rings in which the endothelium had been removed. The augmentation was not present in SHRSP aortic rings that had been similarly denuded. Treatment with indomethacin (5 x 10(-6) M) had no effect on endothelin-induced contraction in either WKY rat or SHRSP aortic rings. Our findings indicate that endothelin and ACh have in common the ability to release endothelium-derived relaxing factor (EDRF) in WKY rat aortic rings. The reduced endothelium-dependent relaxation in response to ACh in the WKY rat probably reflects the fact that endothelin had already released the EDRF in rings from this strain of rats. The release of EDRF by endothelin is less in SHRSP than it is in WKY rats. Because of this failure of endothelin to release EDRF in SHRSP, endothelin may contribute to the increase in total peripheral resistance in this form of hypertension.
Tyrosine-rich crystalloids in a polymorphous low-grade adenocarcinoma. A polymorphous low-grade adenocarcinoma with tyrosine-rich crystalloid deposits is reported. The literature is reviewed, and diagnostic and histogenetic implications of this finding are discussed.
High cholestanol and low campesterol-to-sitosterol ratio in serum of patients with primary biliary cirrhosis before liver transplantation. Serum levels of cholesterol precursors (squalene, delta 8-cholestanol, desmosterol and lathosterol), plant sterols (campesterol and sitosterol), cholestanol and cholestanol/noncholesterol sterol ratios were related to liver damage and liver transplantation indications in healthy controls (n = 26) and in 31 patients with primary biliary cirrhosis divided into group I (S-bilirubin less than 21 mumol/L; n = 14), group II (S-bilirubin 21 to 108 mumol/L; n = 7) and group III (elected for liver transplantation; S-bilirubin 109 to 520 mumol/L; n = 10). The mean serum respective lathosterol levels in controls and in group I were three and two times higher than those in groups II and III, respectively. The plant sterol contents were higher in group II than in groups I and III and the campesterol/sitosterol ratios were lowest in group III. The serum cholestanol levels were high even in group I (i.e., in patients without icterus) and increased progressively to group III, up to 6 and 13 times those in group I and the control group, respectively. The cholestanol/noncholesterol sterol ratios increased progressively from the controls to groups I, II and III. The serum cholestanol levels were positively related to serum bilirubin levels in all primary biliary cirrhosis patients (n = 31, r = 0.906) and to the plant sterol levels in the control group and group I, but significantly negatively in group III. The cholestanol vs. precursor sterol correlations were negative in most cases.
A randomised double-blind study of interpleural analgesia after cholecystectomy. Continuous interpleural analgesia provided by 4 hourly injections of 20 ml bupivacaine 0.5% with adrenaline 5 micrograms/ml was compared with placebo in a randomised, double-blind study after cholecystectomy. All patients self-administered intravenous morphine using a patient-controlled analgesia device. There was a highly significant difference in mean morphine consumption between the groups (72 mg as compared with 22 mg). Visual analogue pain scores tended to be lower in the bupivacaine group throughout and this was significant at 2 hours. Respiratory function measurements were not significantly different between the groups. The mean peak venous plasma bupivacaine concentration after the sixth dose was 3.03 micrograms/ml and no symptoms suggestive of local anaesthetic toxicity occurred. It is concluded that this regimen can provide effective and continuous analgesia after cholecystectomy and that combined administration of interpleural bupivacaine and systemic morphine is more effective than morphine alone in the immediate postoperative period. The doses of bupivacaine required for optimal use of the technique lead to significant total plasma bupivacaine concentrations within 24 hours.
Shear stress induces not only platelet aggregation but also platelet-tumor cell interaction. To investigate the interaction between platelets and tumor cells under well-defined flow conditions, the effect of tumor cells on platelet aggregation induced by shear stress was studied using a cone and plate viscometer adapted for measuring transmitted light intensity. Aggregation was markedly enhanced by HMV-1 cells in a cell number-dependent fashion under shear stress of 12 dyne/cm2. Enhancement was not observed at a high shear stress of 108 dyne/cm2. A monoclonal antibody against GPIIb/IIIa, 7E3 completely abolished enhancement of aggregation by HMV-1. Apyrase had similar inhibitory effects. Scanning electronmicroscopy showed that direct contacts of platelets with HMV-1 cells could be demonstrated when platelet-platelet interaction was inhibited by 7E3 or apyrase. These results may indicate that, at a shear stress of 12 dyne/cm2, direct contacts of platelets and HMV-1 cells may trigger enhancement of platelet aggregation.
Percutaneous balloon dilatation of benign biliary strictures. Percutaneous biliary dilatation is an effective alternative to surgical management of benign biliary strictures that has low morbidity and no reported mortality. Reported success rates for this procedure range from 40% to 90% depending on the size of the series, the type of patient being treated, and the length of follow-up period. The procedure is done in the fluoroscopy suite with an angioplasty balloon catheter. Transhepatic access is most common, but the procedure may be done via existing T-tube tracts or specially created jejunal loops. As the frequency of radical liver surgery such as liver transplant and radical trisegmentectomy rises, so too, the rate of biliary stricture is likely to rise, making percutaneous balloon dilatation an increasingly important tool in the interventional radiologist's armamentarium.
The mouse insulin-like growth factor type-2 receptor is imprinted and closely linked to the Tme locus. T-associated maternal effect (Tme) is the only known maternal-effect mutation in the mouse. The defect is nuclear-encoded and embryos that inherit a deletion of the Tme locus from their mother die at day 15 of gestation. There are many genomically imprinted regions known in the mouse genome but so far no imprinted genes have been cloned. The Tme locus is absent in two chromosome-17 deletion mutants, Thp and the tLub2, and its position has been localized using these deletions to a 1-cM region. We report here that the genes for insulin-like growth factor type-2 receptor (Igf2r) and mitochondrial superoxide dismutase-2 (Sod-2) are absent from both deletions. Probes for these genes and for plasminogen (Plg) and T-complex peptide 1 (Tcp-1) were used in pulsed-field gel mapping to show that Tme must lie within a region of 800-1,100 kb. We also demonstrate that embryos express Igf2r only from the maternal chromosome, and that Tcp-1, Plg and Sod-2 are expressed from both chromosomes. Therefore Igf2r is imprinted and closely linked or identical to Tme.
Rupture of a giant carotid aneurysm after extracranial-to-intracranial bypass surgery. We report a case of a fatal rupture of a previously unruptured giant aneurysm of the bifurcation of the internal carotid artery (ICA), which occurred after an extracranial-intracranial (EC-IC) bypass and the partial occlusion of the ICA. Interim angiography showed retrograde filling of the proximal middle cerebral artery to the aneurysm. There have been four previously reported cases of giant aneurysms rupturing after treatment with an EC-IC bypass and carotid ligation, and it appears likely that a change in pressure/flow dynamics produced by the bypass may have been the cause. The technique of carotid ligation with an EC-IC bypass is used frequently to treat unclippable intracranial aneurysms, and the resulting hemodynamic changes need to be considered carefully to prevent this type of complication. To minimize hemodynamic stress on the aneurysm, we suggest that 1) the bypass caliber should be as small as possible consistent with sufficient cerebral blood flow after ICA occlusion, and 2) complete ICA occlusion should be performed as soon as possible after the bypass.
L-tyrosine potentiates the anorexia induced by mixed-acting sympathomimetic drugs in hyperphagic rats. The effects of L-tyrosine (L-TYR) on the anorectic activity of several mixed-acting sympathomimetics were determined during the dark cycle in rats made hyperphagic by food deprivation. L-TYR (200 mg/kg) significantly potentiated the anorectic activity of phenylpropanolamine, (-)-ephedrine and (+)-amphetamine by 48, 50 and 37%, respectively. When the dose of L-TYR was varied (25-400 mg/kg), a significant dose-dependent relationship was noted. The observed potentiation was positively correlated with increases in brain TYR concentrations; blockade of L-TYR uptake into the brain by the coadministration of L-valine prevented this potentiation. Various other L-amino acids, as well as D-TYR, failed to mimic the potentiating action of L-TYR. As determined by alpha-methyl-p-TYR pretreatment, the L-TYR-induced potentiation was dependent upon increased catecholamine synthesis. Although various other mixed-acting sympathomimetic anorexiants were similarly potentiated by L-TYR, the direct-acting beta-2 adrenoceptor anorexiants, salbutamol and methoxyphenamine, were not. These results indicate that L-TYR specifically potentiates the anorectic activity of the studied mixed-acting sympathomimetics and are consistent with the requirement of the central conversion of L-TYR to catecholamines via TYR hydroxylase for this response. The possibility that the effect of mixed-acting sympathomimetics is normally limited by the availability of L-TYR is suggested.
Total occlusion of the left main coronary artery in a young woman with survival: a case report. The total occlusion of the left main coronary artery (LMCA) is rare, and the survival depends on the existence of collateral circulation. The author presents a case of total occlusion of the left main coronary artery with survival in a young woman because he thinks this is a very rare case, owing to the sex and age of the patient.