123rc/medical_text huggingface dataset:
Anatomical, physiological, and theoretical basis for the antiepileptic effect of vagus nerve stimulation. The vagus is a mixed nerve carrying somatic and visceral afferents and efferents. The majority of vagal nerve fibers are visceral afferents and have a wide distribution throughout the central nervous system (CNS) either monosynaptically or via the nucleus of the solitary tract. Besides activation of well-defined reflexes, vagal stimulation produces evoked potentials recorded from the cerebral cortex, the hippocampus, the thalamus, and the cerebellum. Activation of vagal afferents can depress monosynaptic reflexes, decrease the activity of spinothalamic neurons, and increase pain threshold. Depending on the stimulation parameters, vagal afferent stimulation in experimental animals can produce electroencephalographic (EEG) synchronization or desynchronization and has been shown to affect sleep states. The desychronization of the EEG appears to depend on activation of afferent fibers that have conduction velocities of less than or equal to 15 m/s. Vagal afferent stimulation can also influence the activity of interictal cortical spikes produced by topical strychnine application, and either attenuate or stop seizures produced by pentylenetetrazol, 3-mercaptoproprionic acid, maximal electroshock, and topical alumina gel. The mechanisms for the antiepileptic effects of vagal stimulation are not fully understood but probably relate to effects on the reticular activating system. The vagus provides an easily accessible, peripheral route to modulate CNS function.
Neuroleptic malignant syndrome. When levodopa withdrawal is the cause. Neuroleptic malignant syndrome has been described in patients receiving dopamine antagonists and in a few patients after withdrawal of dopaminergic antiparkinson therapy. Complications affect almost all organ systems and can be life-threatening. Most patients have fever, altered level of consciousness, bradykinesia, and rigidity. Treatment includes withdrawal of the causative agent and supportive therapy for complications. When withdrawal of a dopaminergic medication is the suspected cause, the agent should be reinstated.
Final report of the French multicenter phase II study of the nitrosourea fotemustine in 153 evaluable patients with disseminated malignant melanoma including patients with cerebral metastases. One hundred sixty-nine patients with histologic evidence of disseminated malignant melanoma, including patients with cerebral metastases, were entered into a Phase II study of the nitrosourea fotemustine. The treatment regimen consisted of a 100 mg/m2 1 hour IV infusion every week for 3 consecutive weeks, followed by a 4- to 5-week rest period (induction therapy). In responding or stabilized patients, maintenance therapy consisted of 100 mg/m2 every 3 weeks until the disease progressed. One hundred fifty-three patients were evaluable for response. Three complete responses and 34 partial responses were observed (according to the World Health Organization criteria), leading to an objective response rate of 24.2% (95% confidence interval: 17.4% to 31.0%). Responses were also documented on cerebral (25.0%), visceral (19.2%), or nonvisceral (31.8%) metastatic sites. The median duration of response was 22 weeks (range, 7 to 80 weeks). The objective response rate in previously untreated patients was 30.7% (19 of 62 patients). The main toxicity was hematologic with delayed and reversible leukopenia and/or thrombopenia. The objective response rate observed (especially in untreated patients), the activity on cerebral metastases, and the small amount of extra-hematologic toxicity encountered suggest that fotemustine is an effective drug in disseminated malignant melanoma.
Disability from bicycle-related injuries in children. Bicycle crashes are a major cause of injuries in childhood. The goal of this study was to determine the long-term disabilities caused by bicycle-related injuries, and to clarify the long-term treatment priorities of injured children. Hospital records of 372 children (ages 2-15 yr, median 9 yr; 232 boys and 140 girls) admitted with bicycle-related injuries from 1979 through 1986 provided clinical information, social service visits, in-hospital and outpatient rehabilitative interventions, and physical status at discharge. More complete evaluations were made by contacting parents by telephone (82 children), and by personal interview and physical examinations (27). Head injuries predominated (69.1%). Twelve (3.2%) died, all from major head injuries. Four suffered permanent severe impairment from cervical spinal injuries and head injuries and remain institutionalized (1.4%). One third had a persistent disability noted at the time of discharge in the medical record (33.6%), reported by telephone interview (31.7%), or confirmed by physical examination (37.0%). Still, only 11.0% received physical therapy consultations during hospitalization, and 22.8% received social service assistance. Only 39.0% were seen by a surgeon or pediatrician after discharge, and few (7.3%) received outpatient physical therapy. Cognitive or behavior changes were noted in 31.7%, many noting changes in school performance (worse in 20.7%), behavior (13.4%), and sleep, particularly nightmares (34.1%). Recurrent injuries occurred in 52 children (14.4%), of whom ten (2.8%) required further hospital admission. Bicycle-related injuries cause significant short- and long-term disabilities among children.
Timing and mechanism of in-hospital and late death after primary coronary angioplasty during acute myocardial infarction. The effect of early myocardial reperfusion on patterns of death after acute myocardial infarction (AMI) is unknown. Thus, the mechanism and timing of in-hospital and late deaths among a group of 614 patients treated with coronary angioplasty without antecedent thrombolytic therapy for AMI were determined. Death occurred in 49 patients (8%) before hospital discharge. Four patients died in the catheterization laboratory. Death was due to cardiogenic shock in 22 patients, acute vessel reclosure in 5 patients, was sudden in 8 patients and followed elective coronary artery bypass surgery in 8 patients. Cardiac rupture was observed in only 2 patients after failed infarct angioplasty, and did not occur among the 574 patients with successful infarct reperfusion. Intracranial hemorrhage did not occur. Multivariate predictors of in-hospital death included failed infarct angioplasty, cardiogenic shock, 3-vessel coronary artery disease and age greater than or equal to 70 years. During a follow-up period of 32 +/- 21 months (range 1 to 87), 55 patients died. The cause of death was cardiac in 36 patients, including an arrhythmic death in 23 patients and was due to circulatory failure in 13 others. One patient died of reinfarction due to late reclosure of the infarct artery. Actuarial survival curves demonstrated overall survival after hospital discharge of 95 and 87% at 1 and 4 years, respectively. Freedom from cardiac death at 1 and 4 years was 96 and 92%. Multivariate predictors of late death included 3-vessel disease, a baseline ejection fraction of less than or equal to 40%, age greater than 70 years and female gender.
Results and complications of angioplasty in fibromuscular disease. Percutaneous transluminal angioplasty (PTA) was used to treat 66 patients with 85 renal artery stenoses due to fibromuscular dysplasia. The hypertension was refractory to medical management in 46 patients, and the initial success rate was 100%. Clinical follow-up has been obtained in all patients, who were followed for as long as 121 months. The recurrence rates were 8% of lesions and 10% of patients. Cumulative patency rate predicted for 10 years was 87.07%. The mean systolic pressure decreased by 52 mm Hg and the mean diastolic pressure decreased by 35 mm Hg in response to treatment. Twenty-six patients (39%) were cured, 39 (59%) were classified as improved, and one (2%) did not respond to PTA. Fourteen of the patients also had elevated blood urea nitrogen and creatinine levels. Renal function was improved in 86% of the patients and stabilized in 14% of the patients. Analysis of the long-term results suggests that PTA should be the initial treatment for choice of patients with fibromuscular dysplasia in the renal arteries.
Mean arterial blood pressure changes in premature infants and those at risk for intraventricular hemorrhage. Bedside microcomputer-derived, minute-to-minute mean arterial pressure (MAP) values during the first 48 hours of life were studied in 100 preterm babies with birth weight less than or equal to 1500 gm. In those babies (n = 72) with no periventricular-intraventricular hemorrhage (PV-IVH) or with grade 1 PV-IVH, the MAP values increased during the study period, with minute-to-minute variation and interval undulation. The MAP values in those with birth weight greater than 1000 gm were higher than in those of lower birth weight. Infants in whom grades 2 to 4 PV-IVH developed (n = 28) had consistently lower MAP values during the study period. Minute-to-minute variability, expressed as the average of the coefficients of variation at 15-minute intervals, did not differ between birth weight groups, nor did they differ between the PV-IVH group and their matched control subjects. However, those with PV-IVH spent a greater percentage of time, with a coefficient of variation greater than or equal to 13% or less than 3%, than their matched control subjects spent (p less than 0.005). This study provides reference data for MAP changes in premature babies. The observed MAP changes in those with PV-IVH lend support to a significant role for MAP alterations in the pathogenesis of PV-IVH.
Imaging of patients with stage D prostatic carcinoma. In conclusion, it would appear from present evidence that several statements can be made. First, MRI is the most accurate method of staging the periprostatic spread of carcinoma. Both the prostate and the regional nodes can be evaluated. The role of ultrasound is, at present, unclear. Second, the utility of CT has diminished with the emergence of high-quality MRI, but in situations in which MRI scans are inconclusive (e.g., in the assessment of paraaortic node disease, in which images are degraded by peristaltic movement), CT may be useful. Third, the choice of method for the assessment of nodal disease is a more difficult question. Although MRI and CT have replaced lymphography in most centers, the latter study, especially when combined with fine-needle aspiration biopsy, still is useful. Fourth, bone metastases are best assessed with scintigraphy, which can point to areas requiring supplemental plain radiography. An MRI study of the spine, although highly sensitive, is not practical. Fifth, MRI is superior to CT myelography in assessing spinal disease. Finally, the chest radiograph is the mainstay of assessing chest involvement.
Loss of photosynthetic and chlororespiratory genes from the plastid genome of a parasitic flowering plant. Photosynthesis is the hallmark of plant life and is the only plastid metabolic process known to be controlled by plastid genes. The complete loss of photosynthetic ability, however, has occurred on several independent occasions in parasitic flowering plants. Some of these plants are known to lack chlorophyll and certain photosynthetic enzymes, but it is not known to what extent changes have occurred in the genes encoding the photosynthetic apparatus or whether the plants even maintain a plastid genome. Here we report that the nonphotosynthetic root parasite Epifagus virginiana has a plastid chromosome only 71 kilobases in size, far smaller than any previously characterized land plant plastid genome. The Epifagus plastid genome has lost most, if not all, of the 30 or more chloroplast genes for photosynthesis and most of a large family of plastid genes, the ndh genes, whose products may be involved in a plastid respiratory chain. The extensive changes in Epifagus plastid gene content must have occurred in a relatively short time (5-50 x 10(6) yr), because Striga asiatica, a related photosynthetic parasite, has a typical complement of chloroplast genes for photosynthesis and chlororespiration. The plastid genome of Epifagus has retained transcribed ribosomal RNA and ribosomal protein genes, suggesting that it expresses one or more gene products for plastid functions not related to photosynthesis.
Hepatic infarction in preeclampsia. Two cases of hepatic infarction in toxemia of pregnancy are described. Both patients had associated laboratory findings of the HELLP syndrome (hemolytic anemia, elevated liver enzyme levels, and low platelet levels). Computed tomography (CT) showed nonenhancing low-attenuation areas varying in configuration from peripheral, well-defined, wedge-shaped lesions to larger abnormalities. Magnetic resonance imaging showed a corresponding area of low signal intensity on T1-weighted images with high signal intensity on T2-weighted images. Ultrasound showed several well-defined peripheral hypoechoic areas. The low attenuation and lack of enhancement on CT scans and the absence of mass effect are the key distinguishing features.
Human coronary transplantation-associated arteriosclerosis. Evidence for a chronic immune reaction to activated graft endothelial cells. Occlusive disease of coronary arteries of engrafted hearts is the major obstacle to long-term survival of human cardiac allografts. The pathogenesis of this process remains uncertain. The identity and localization of cells found in transplantation-associated arteriosclerosis lesions from human cardiac allografts were evaluated, and their expression of class II major histocompatibility complex (human leukocyte antigen-DR [HLA-DR]), surface molecules required for recognition of foreign cells by CD4+ T lymphocytes, was noted. Expanded intimas of transplanted coronary arteries contain T lymphocytes (both CD4+ and CD8+ in approximately equal number) and HLA-DR+ macrophages, both localized primarily in a ring immediately below the luminal endothelium, a distribution strikingly different from that in typical atherosclerosis. Coronary arterial endothelium from six of six transplanted hearts studied bore high levels of HLA-DR. Normal human arteries or usual atherosclerotic lesions have few if any HLA-DR+ endothelial cells. The significance of these findings was tested by evaluating the ability of HLA-DR+ arterial cells to interact with allogeneic T cells in vitro. Endothelial cells (but not smooth muscle cells) cultured from human arteries stimulated foreign CD4+ T cells to proliferate and augmented their secretion of interleukin-2. These findings suggest that ongoing stimulation of recipient T lymphocytes by HLA-DR+ endothelium of donor coronary arteries contributes to a sustained regional immune response. Consequent local release of cytokines may regulate smooth muscle cell proliferation and matrix accumulation within the coronary arteries of allografted hearts.
Effect of amiodarone on erythrocyte shape and membrane properties. 1. Amiodarone is a potent anti-arrhythmic drug with lipophilic properties. The intercalation of such a drug into the membrane of erythrocytes may alter their shape and have an impact on the flow properties of blood. We therefore studied the influence of amiodarone on erythrocyte shape and deformability in vitro and in vivo. 2. Incubation in vitro with increasing amiodarone concentrations led to a progressive stomatocytic shape transformation and a decreased deformability of the erythrocytes. 3. Amiodarone treatment in eight patients did not affect erythrocyte morphology and deformability. However, an increase in the membrane cholesterol/phospholipid ratio was found. 4. The stomatocytic shape transformation of erythrocytes in vitro indicates that amiodarone intercalates in the inner hemileaflet of the lipid bilayer leading to membrane internalization. These results shed light on the interaction of amiodarone with biomembranes.
Purulent pericarditis and cardiac tamponade caused by Nocardia asteroides in mixed connective tissue disease. Pericardial nocardiosis is extremely rare, but may affect especially immunocompromised hosts. We describe the first reported case of purulent pericarditis with cardiac tamponade as the initial presentation of systemic nocardiosis in a patient with mixed connective tissue disease. Our case emphasizes the importance of identifying infectious causes of pericarditis in patients with connective tissue diseases. Longterm survival was achieved with a combined medical and surgical approach.
Comparison of neuropsychologic functioning and clinical indicators of neurotoxicity in long-term survivors of childhood leukemia given cranial radiation or parenteral methotrexate: a prospective study. We prospectively compared neuropsychologic functioning and clinical indicators of neurotoxicity in 49 consecutive childhood leukemia patients in long-term continuous complete remission (CR) who had received two different regimens of CNS prophylaxis by random assignment. Twenty-three patients were treated with 1,800 cGy cranial radiation and intrathecal methotrexate (RT group) and 26 with parenteral methotrexate only (MTX group). Over half of the RT group had somnolence syndrome, and four developed cerebral calcifications late in their clinical course. Abnormal electroencephalograms (EEGs) were seen in 15 patients in the MTX group, and six had early, transient white-matter hypodensities apparent on computed tomographic (CT) scans. Mean scores on standard tests of intelligence and academic achievement, administered after remission induction and again at a median of 6 years after treatment cessation, did not differ significantly between the two groups. However, statistically significant decreases in overall and verbal intelligence quotients (IQs) and in arithmetic achievement were found within both treatment groups. Sixteen of 26 in the MTX group and 14 of the 23 in the RT group had clinically important decreases (greater than or equal to 15 points) on one or more neuropsychologic measures. These changes did not correlate with findings on CT scans, EEGs, or other clinical signs of neurotoxicity. We conclude that 1,800 cGy cranial radiation and parenteral methotrexate, as used in this study, are associated with comparable decreases in neuropsychologic function.
Treating systemic fungal infections in AIDS patients. Prolonging life against the odds. Fungal infections have become one of the major causes of death among immunocompromised patients, particularly patients with AIDS. Accurate and quick diagnosis is difficult; therefore, empirical therapy is often necessary. This scenario is complicated by the fact that most antifungal agents are toxic at the doses used or relatively ineffective against deep-seated mycoses. Because the population of AIDS patients is increasing, physicians will be faced more often with the management of systemic fungal infections. Despite the current bleak prognosis for these patients, several new antigen detection tests are being developed and triazole agents are proving to be effective and less toxic than their predecessors. Many cases of systemic mycoses do result in mortality, but appropriate treatment can both prolong life and improve its quality.
Indigenous cases of Lyme disease diagnosed in North Carolina. Between January 1984 and December 1989, 102 indigenous cases of Lyme disease were reported in North Carolina. Lyme disease was reported in each of the three major geographic regions of the state: mountain, piedmont, and coastal plain. One or more diagnoses were made in 42 of 100 counties. Patients ranged in age from 5 months to 78 years (median, 27 years); 58 patients (57%) reported a history of tick exposure within 1 month of the onset of symptoms. Erythema migrans was reported by 93 patients (91%). Arthritis (30%), neurologic symptoms (10%), and cardiac abnormalities (7%) were observed. Thirty of the 102 cases were confirmed serologically by indirect fluorescence microscopy or enzyme-linked immunosorbent assay.
Cirrhosis and portal hypertension in a patient with adult Niemann-Pick disease. A woman with known Niemann-Pick disease, type B, presented at age 33 with upper gastrointestinal bleeding, ascites, and peripheral edema. Evaluation showed massive hepatosplenomegaly, infiltration of the liver with Niemann-Pick cells, cirrhosis, and evidence of portal hypertension. Chronic gastrointestinal bleeding, thrombocyctopenia, and platelet dysfunction were treated successfully by splenectomy. Cirrhosis and portal hypertension have not been reported previously in adult Niemann-Pick disease in the absence of some other cause.
Regurgitant jet size by transesophageal compared with transthoracic Doppler color flow imaging. Combined echocardiography and Doppler color flow mapping from transthoracic imaging windows has become the standard method for the noninvasive assessment of valvular regurgitation. This study compared regurgitant jet areas by Doppler color flow imaging derived from the newer transesophageal approach with measurements obtained from conventional transthoracic apical views. Maximal regurgitant jet area determinations and an overall visual estimate of lesion severity were obtained from 42 patients who underwent color flow examination by both techniques. Seventy-three regurgitant lesions were visualized by transesophageal flow imaging: 34 mitral, 22 aortic, and 17 tricuspid jets. Transthoracic studies in the same patients revealed fewer regurgitant lesions for each valve; 20 mitral, 16 aortic, and 12 tricuspid (p = 0.0009). A comparison of maximal jet areas determined by transesophageal and transthoracic studies showed a good overall correlation (r = 0.85, SEE = 2.8 cm2) and a systematic overestimation by the transesophageal technique (TEE = 0.96 TTX + 2.7). For the subgroup with mitral insufficiency, valve lesions visualized by both techniques were larger by the transesophageal approach (n = 18, 6.0 versus 3.6 cm2, p = 0.008). Semiquantitative visual grading of individual valve lesions by two independent observers revealed a higher grade of regurgitation with more jets classified as mild (38 versus 25), moderate (18 versus 13), and severe (17 versus 10) by esophageal imaging than by transthoracic imaging. Thus, transesophageal color flow mapping techniques yield a higher prevalence of valvular regurgitation than do transthoracic techniques in the same patients. Jet area and the overall estimate of regurgitant lesion severity were also greater by transesophageal color Doppler imaging compared with standard transthoracic imaging.
Brachial-jugular polytetrafluoroethylene fistulas for hemodialysis. A retrospective analysis was made of 16 patients who had received a brachial-jugular polytetrafluoroethylene (PTFE) graft for hemodialysis. In four patients, the procedure was used to treat malfunctioning brachio-axillary fistulas due to long venous stenosis in the axillary vein. In 12 other patients, the operation was chosen in cases of exhaustion of the veins in the upper extremity because of previous multiple failed fistulas. Two patients died with a functioning fistula 7 and 10 months after placement of the graft of causes unrelated to the vascular access. The other 14 patients retained functioning fistulas between 8 and 26 months after construction of the shunt. Three patients needed graft thrombectomy to treat occlusive episodes. No venous stenosis was found in a postoperative fistulography made in those patients. One patient needed substitution of a graft segment due to stenosis of the prosthesis crossing over the clavicle. We believe that the brachial-jugular graft is a procedure that can be considered as vascular access for hemodialysis in cases where the use of veins in the upper extremity and the axilla is not possible.
New horizons in management of hypothermia and frostbite injury. Diagnosing hypothermia requires a high index of suspicion. Restoring lost heat with careful attention to hemodynamics usually results in complete recovery. Frostbite is best treated by physicians who are cognizant of the pathophysiology of cold injury. Although alternative methods of intervention are being tested, rapid rewarming and anti-inflammatory agents are integral to treatment protocols.