123rc/medical_text huggingface dataset:
Diagnosis of noninfective cardiac mass lesions by two-dimensional echocardiography. Comparison of the transthoracic and transesophageal approaches. This study was conducted in 46 patients with cardiac thrombi, 15 patients with atrial myxomas, and 32 patients with other cardiac or paracardiac tumors. Diagnoses were subsequently proven by surgery, autopsy, computed tomography, magnetic resonance imaging, or angiography in all patients. All patients underwent precordial and transesophageal two-dimensional echocardiography to assess the various mass detection rates. Atrial myxomas and predominantly left-sided cardiac tumors were identified by both echocardiographic techniques with comparable detection rates. Left ventricular apical thrombi were detected more frequently by precordial echocardiography. In contrast, transesophageal echocardiography was superior in visualizing left atrial appendage thrombi, small and flat thrombi in the left atrial cavity, thrombi and tumors in the superior vena cava, and masses attached to the right heart and the descending thoracic aorta. These data indicate that transesophageal echocardiography leads to a clinically relevant improvement of the diagnostic potential in patients in whom cardiac masses are suspected or have to be excluded in order to ensure the safety of clinical procedures.
Electron-microscopic identification of pseudoexfoliation material in extrabulbar tissue. The structure and distribution of pseudoexfoliation material in extrabulbar tissues from five eyes with typical unilateral intraocular pseudoexfoliation syndrome and two intraocularly unaffected fellow eyes were examined by transmission electron microscopy. In all seven eyes, unevenly distributed pseudoexfoliation aggregates were found in limbal conjunctivae, extraocular rectus and oblique muscles, orbital connective-tissue septa, and the walls of the posterior ciliary arteries, vortex veins, and central retinal vessels passing through the optic nerve sheaths. Typical pseudoexfoliation fibers occurred in close association with connective-tissue components, especially elastic fibers; a moderate predisposition of pseudoexfoliation clumps to accumulate around blood vessels was observed. The findings of pseudoexfoliation material in similar extrabulbar locations in intraocularly uninvolved fellow eyes indicates that pseudoexfoliation fiber formation outside the globe precedes its intraocular manifestation. The intermingling of pseudoexfoliation fibers, microfibrils, and elastic and collagen fibers suggests that pseudoexfoliation fiber formation might result from a disordered synthesis and/or assembly of connective-tissue microfibrils.
Hippocampal sclerosis can be reliably detected by magnetic resonance imaging. Two independent blinded observers reported the preoperative MRIs in a series of 81 consecutive patients with intractable temporal lobe epilepsy who were undergoing temporal lobectomy. We then compared the nature and lateralization of the MRI abnormalities with the pathologic diagnosis and the side of lobectomy. The MRI criteria of hippocampal sclerosis were an increased T2-weighted signal and the signal's confinement to a unilaterally small hippocampus. Imaging was performed in coronal and axial planes, specially orientated along and perpendicular to the long axis of the hippocampal body. We found diagnostic MRI abnormalities in 25 of the 27 cases with pathologically proven hippocampal sclerosis (sensitivity 93%, specificity 86%). In addition, we detected all 13 foreign tissue lesions on MRI. Overall, we detected lateralized lesions on MRI that correctly predicted the side of the epileptogenic temporal lobe in 72 cases (89%), with 2 possible errors. A learning effect in appreciating the relatively subtle MRI changes of hippocampal sclerosis was apparent in our later cases, as shown by an improved correlation between the 2 observers. This study demonstrates that hippocampal sclerosis can be identified on MRI with a high degree of sensitivity and specificity.
Spinal cord stimulation: a contemporary series Forty-three patients with chronic pain disorders of different causes were selected for spinal cord stimulation. All underwent implantation of a ribbon electrode through a small laminotomy, under general anesthesia. Thirteen patients (30%) failed to obtain significant pain relief during a period of trial stimulation, and their electrodes were removed. The remainder underwent a definitive implant and were followed for a mean of 13 months (range, 3-33 months). Nineteen of them (63%) continued to experience pain relief. A detailed analysis of this series, as well as a literature review, is presented.
Molteno implants and operating microscope-induced retinal phototoxicity. A clinicopathologic report. The right eye of a 75-year-old man with a history of cataract extraction, three penetrating keratoplasties, laser trabeculoplasty, two Molteno implants, and an operating microscope-induced retinal phototoxic lesion was studied post mortem. Histopathologic examination of the anterior segment showed evidence of penetrating keratoplasty, cataract surgery, and two Molteno implants with minimal associated tissue response. Ultrastructural examination showed a loose collagenous matrix surrounding the Molteno reservoirs, suggesting aqueous percolation from the reservoirs into the conjunctiva. Posteriorly, in the area of the phototoxic operating microscope-induced lesion, a nodule of retinal pigment epithelial hyperplasia with overlying atrophy of the photoreceptor cell layer of the neurosensory retina was noted. The retina also contained cystoid macular edema and an extensive preretinal membrane that was clinically unexpected.
Pregnancy associated with Gorlin's syndrome. A pregnant woman with Gorlin's syndrome presented for the removal of malignant ovarian tumours. The main problem encountered by the anaesthetists was an unexpected increase in arterial blood pressure. This was most probably associated with surgical manipulation of the ovaries with an increase in prorenin/renin production.
Compound blue nevus: a variant of blue nevus with an additional junctional dendritic component. A clinical, histopathologic, and immunohistochemical study of six cases. We studied six cases of heavily pigmented melanocytic lesions with features of blue nevi within the dermis, but with an additional junctional dendritic component. This compound variant of blue nevus is an uncommon lesion that has not been previously identified as a distinct histologic entity. Immunoperoxidase staining for S100 protein and counterstaining with azure B distinguished the presence of melanocytes among numerous melanophages within the dermis. The compound variant of blue nevus can be distinguished histologically from combined blue nevus, pigmented spindle cell nevus, malignant melanoma, and melanosis due to a regressed malignant melanoma. The six lesions were from three men and three women whose ages ranged from 11 to 51 years (mean, 31 years). Three lesions were located on the trunk, two on the extremities, and one on the head. After a mean follow-up period of 47 months (range, 38 to 58 months), there was no evidence of recurrence.
Anaesthetic management of the brain dead for organ donation. An increasing number of anaesthetists is being called upon to manage organ donors during organ retrieval procedures. We briefly describe the technical aspects of the surgical procedure together with a guide to the anaesthetic management. The aims of the latter may be summarized as the "Rule of 100": systolic blood pressure greater than 100 mmHg, urine output greater than 100 ml.hr-1, PaO2 greater than 100 mmHg, haemoglobin concentration greater than 100 g.L-1. Common management problems (hypotension, arrhythmias, diabetes insipidus, oliguria, and coagulopathy) are discussed in detail. The intraoperative management of the brain-dead organ donor provides the anaesthetist with the challenge of a major surgical procedure in a subject with important physiological derangements.
Unilateral diffuse pulmonary artery involvement in Takayasu's arteritis associated with coronary-pulmonary artery fistula and bronchial-pulmonary artery fistula: a case report. Diffuse involvement of the right pulmonary artery associated with fistulas between the pulmonary artery and systemic artery is reported in a woman with Takayasu's arteritis. The most proximal portion of the abdominal aorta was pronouncedly narrowed and the aortic wall was markedly calcified. Both the celiac artery and the superior mesenteric artery were totally occluded and drained by the meandering artery arising from the inferior mesenteric artery. The proximal right pulmonary artery was focally narrowed and the middle lobe artery was occluded. All other branches of the right pulmonary artery were diffusely narrowed with sparse distributions of their distal branches. Fistulas were identified between the right coronary artery and the right pulmonary artery and between the right bronchial artery and the right pulmonary artery. This is the first English report of Takayasu's arteritis presenting with a coronary-pulmonary artery fistula that is secondary to a diffuse unilateral involvement of the pulmonary artery.
Catheter modification of the atrioventricular junction with radiofrequency energy for control of atrioventricular nodal reentry tachycardia. BACKGROUND. The utility of transcatheter application of radiofrequency energy to eliminate atrioventricular nodal reentrant tachycardia (AVNRT) was investigated. METHODS AND RESULTS. Thirty-nine patients (mean age, 53 +/- 20 years; range 14-86 years) with medically refractory AVNRT underwent perinodal ablation with radiofrequency energy. A custom-designed 6F catheter with a large (3-mm-long) distal electrode and interelectrode pacing of 2 mm was used in the majority of cases. The catheter used for ablation was initially positioned across the tricuspid anulus to obtain the largest His bundle electrogram, then withdrawn to obtain the largest atrial:ventricular electrogram ratio, with a small His bundle electrogram (less than or equal to 100 microV). Each application of radiofrequency energy (350-550 kHz, 16.2 +/- 5.2 W) was stopped after 60 seconds or if PR prolongation or an impedance rise was noted. The endpoints of the procedure were persistent modification of atrioventricular nodal conduction (either first-degree atrioventricular block or impairment of ventriculoatrial conduction) and noninducibility of AVNRT before and during isoproterenol administration. Radiofrequency energy was applied a mean of 6.8 +/- 3.5 times per session. After a mean follow-up of 8 +/- 3.0 months, 32 of the 39 patients (82%) have been free of AVNRT, and did not have high grade AV block. Three patients (8%) developed complete atrioventricular block and had pacemakers implanted. Two patients had unsuccessful initial procedures, and two patients had initially successful ablations but had recurrences of tachycardia 4-6 weeks later. Elimination of AVNRT appeared to be due to effects on the retrograde fast pathway in most patients. CONCLUSIONS. Radiofrequency ablation of the perinodal right atrium appears to be safe and effective for treatment of typical AVNRT.
Patterns of chromosomal breakpoint locations in Burkitt's lymphoma: relevance to geography and Epstein-Barr virus association. We have examined, by Southern blotting, the patterns of chromosomal breakpoint locations in 55 cases of Burkitt's lymphoma (BL) with respect to geography and Epstein-Barr virus (EBV) association. We have confirmed the association between chromosome 8 breakpoint and geography: 74% of endemic (eBL) but only 9% of sporadic BL (sBL) had breakpoints outside the HindIII fragment encompassing the c-myc gene (P2 less than .00001). Conversely, not only did 91% of sBL manifest a rearranged HindIII fragment, but at least 56% of these cases, in contrast to 17% of eBL cases, had a breakpoint within the first exon or intron of c-myc (P2 less than .004). Breakpoints outside the switch mu (S mu) region (ie, the HindIII fragment encompassing S mu) on chromosome 14 were twice as common overall (73%) as those within S mu (27%), but in the 15 tumors with S mu breakpoints, 13 (87%) had a rearranged c-myc gene. Breakpoints outside the HindIII fragment encompassing c-myc on chromosome 8 were predominantly associated with non-S mu breakpoints on chromosome 14 (85%) and this was the combination most frequently associated with eBL (65%; 6% of sBL, P2 less than .00001). In sBL, the most frequent breakpoint combination was a rearranged c-myc gene with a non-S mu breakpoint (63%; 13% of eBL). Twenty-eight percent of sBL and 13% of eBL had breakpoints both within c-myc and within S mu. EBV DNA was present in 19 of 20 tumors with breakpoints outside c-myc, in none of 7 with a breakpoint in the immediate 5' region of c-myc, in 4 of 5 tumors with breakpoints in the first exon, and in 7 of 12 tumors with breakpoints in the first intron. These data suggest that the pathogeneses of eBL and sBL differ with regard to the mechanism of c-myc deregulation, and probably also with regard to the state of differentiation of the target cell for malignant transformation. We have formulated a testable hypothesis regarding the potential role of EBV in pathogenesis: that it is required to contribute to the deregulation of c-myc in the presence of some, but not all, types of c-myc damage arising from the chromosomal translocations.
Valproate metabolism during hepatotoxicity associated with the drug. Plasma concentrations of valproate and certain of its metabolites and their patterns of excretion in urine are described in three adults who developed hepatotoxicity during treatment of epilepsy with sodium valproate. One patient also developed a degree of reversible renal insufficiency, whilst another may have had associated infectious mononucleosis. All three cases showed evidence of impaired mitochondrial beta-oxidation of valproate. In one the impairment was at the stage catalysed by fatty acyl-CoA dehydrogenase, in another at the stage catalysed by 3-hydroxyacyl-CoA dehydrogenase and in the third at the stage catalysed by enoyl-CoA hydratase and possibly also at the next stage catalysed by 3-hydroxyacyl-CoA dehydrogenase. The impaired beta-oxidation meant that valproate metabolism was diverted into various alternative pathways. Plasma concentrations of the suspected hepatotoxic metabolite 4-en-valproate were normal for the valproate-treated population in all cases. By analogy with certain spontaneous and acquired human disorders of branched chain amino acid metabolism, it is suggested that valproate-associated hepatotoxicity may represent the consequences of a valproate overload on a limited mitochondrial beta-oxidation capacity, causing accumulation of a toxic product of endogenous branched chain amino acid metabolism.
Experimental reduction of portal hypertension by mechanical increase of liver portal flow Studies on the isolated perfused rat liver demonstrated that an increase in portal pressure is associated with an increase in the portal blood flow in normal and in cirrhotic livers. In two pigs with portal hypertension mesenteric portal pressure was lowered by mechanically increasing the liver portal blood flow by means of a balloon pump around the portal vein.
Red cell autoantibodies, multiple immunoglobulin classes, and autoimmune hemolysis. The effects and interrelationships of multiple immunoglobulin coating (i.e., increased red cell [RBC]-bound IgM and/or IgA in addition to IgG) were investigated in 404 patients with warm-reactive RBC autoantibodies on 590 occasions. Multiple immunoglobulins were detected by enzyme-linked direct antiglobulin tests in 218 samples (37%), but in only 87 (15%) by agglutination methods. Differences in populations were examined by chi-square, with p less than 0.005 being required for significance because of the multiple tests. Compared with IgG coating alone, multiple immunoglobulins were significantly associated with larger quantities (greater than 800 molecules/RBC) of IgG, multiple IgG subclasses, IgG3 and C3d bound to the cells, and with serum haptoglobin levels of less than 0.1 g per L. The latter association was still significant when higher levels of RBC-bound IgG and subclass pattern were taken into account. In samples with multiple immunoglobulin coating, there was no significant relationship (p greater than 0.05) between haptoglobins of less than 0.1 g per L and either C3d or multiple IgG subclasses. It was concluded that multiple immunoglobulin coating, even when undetected by agglutination methods, is a major cause of hemolysis: it is part of a more generalized autoimmune response and acts with other factors such as the quantity of bound IgG, the IgG subclass pattern, and complement; it also has an important hemolytic effect in its own right.
Occupational sunlight exposure and melanoma in the U.S. Navy. Melanoma is the second most common cancer, after testicular cancer, in males in the U.S. Navy. A wide range of occupations with varying exposures to sunlight and other possible etiologic agents are present in the Navy. Person-years at risk and cases of malignant melanoma were ascertained using computerized service history and inpatient hospitalization files maintained at the Naval Health Research Center. A total of 176 confirmed cases of melanoma were identified in active-duty white male enlisted Navy personnel during 1974-1984. Risk of melanoma was determined for individual occupations and for occupations grouped by review of job descriptions into three categories of sunlight exposure: (1) indoor, (2) outdoor, or (3) indoor and outdoor. Compared with the U.S. civilian population, personnel in indoor occupations had a higher age-adjusted incidence rate of melanoma, i.e., 10.6 per 100,000 (p = .06). Persons who worked in occupations that required spending time both indoors and outdoors had the lowest rate, i.e., 7.0 per 100,000 (p = .06). Incidence rates of melanoma were higher on the trunk than on the more commonly sunlight-exposed head and arms. Two single occupations were found to have elevated rates of melanoma: (1) aircrew survival equipmentman, SIR = 6.8 (p less than .05); and (2) engineman, SIR = 2.8 (p less than .05). However, there were no cases of melanoma or no excess risk in occupations with similar job descriptions. Findings on the anatomical site of melanoma from this study suggest a protective role for brief, regular exposure to sunlight and fit with recent laboratory studies that have shown vitamin D to suppress growth of malignant melanoma cells in tissue culture. A mechanism is proposed in which vitamin D inhibits previously initiated melanomas from becoming clinically apparent.
Myeloma manifesting as a large jugular tumor: case report. The authors report a case of cranial plasmacytoma with multiple myelomas and palsy of the lower cranial nerves. The osteolytic lesion adjacent to the jugular foramen was demonstrated by an angiogram to be exceedingly hypervascular, with arteriovenous shunting resembling that seen in paragangliomas. Forty-five cases of cranial and intracranial plasmacytoma from the literature were reviewed. The findings indicate that a cranial plasmacytoma commonly appears to be a hypervascular tumor, whereas most dural tumors or intraparenchymal tumors have poor vascularity.
Cardiorespiratory effects of antagonism of diazepam sedation with flumazenil in patients with cardiac disease. The specific benzodiazepine antagonist flumazenil is currently under intense study. Despite much clinical experience, no detailed invasive hemodynamic studies of its use in cardiac patients have been published. In the present study, hemodynamic and respiratory variables were measured in 10 cardiac patients undergoing catheterization of the right and left sides of the heart, before and after sedation with intravenous diazepam, and after reversal of sedation with flumazenil. A sleep dose of diazepam (12.2 +/- 5.1 mg, mean +/- SD) caused only slight decreases in mean arterial pressure (103 +/- 12 to 98 +/- 14 mm Hg; P less than 0.05), pulmonary capillary wedge pressure (13.2 +/- 6.3 to 11.7 +/- 6.6 mm Hg; P less than 0.05), and left ventricular end-diastolic pressure (20.8 +/- 7.5 to 17.3 +/- 10.0 mm Hg; P less than 0.05), with no significant changes in respiratory gas homeostasis. Intravenous flumazenil (0.22 +/- 0.07 mg) resulted in spontaneous awakening and return to full orientation, yet caused no significant alteration in either hemodynamic or respiratory variables measured. Reversal of diazepam-induced sedation by flumazenil in cardiac patients appears safe and effective.
Restoration by insulin of impaired prostaglandin E1/I2 receptor activity of platelets in acute ischemic heart disease. Treatment of normal platelet-rich plasma with a physiological amount of insulin (100 microunits/ml, optimum concentration) for 3 hours at 23 degrees C stimulated the binding of prostaglandin E1 by more than twofold (3,940 +/- 250 sites/10(8) platelets) compared with the nontreated, control platelet-rich plasma (1,590 +/- 265 sites/10(8) platelets). After platelet-rich plasma from patients with acute ischemic heart disease (n = 43), whose platelets showed impaired prostaglandin E1/I2 receptor activity (850 +/- 100 sites/10(8) platelets), was incubated with insulin (optimum amounts varied from 100 to 200 microunits/ml), the binding of the prostanoid was restored to normal levels (1,790 +/- 140 sites/10(8) platelets) in 75% of the cases. Twenty-five percent of the patients did not respond to the stimulatory effect of insulin. The increased binding of the prostanoid to the insulin-treated platelets also resulted in increased cyclic AMP levels both in normal subjects (44.14 +/- 3.1 pmol/10(8) [insulin-treated] platelets versus 16.35 +/- 2.91 pmol/10(8) [control] platelets) and in patients with acute ischemic heart disease (23.87 +/- 4.1 pmol/10(8) [insulin-treated] platelets versus 7.70 +/- 2.0 pmol/10(8) [control] platelets) by the prostanoid (1.0 microM). The treatment of platelet-rich plasma with the hormone decreased the minimum inhibitory concentration of the prostanoid from 34 +/- 14 to 15 +/- 9 nM (p less than 0.001) in the case of normal volunteers and from 49 +/- 15 to 32 +/- 11 nM (p = 0.002) in the case of "responder" patients. Insulin did not produce any effect on the inhibition of platelet aggregation by the prostaglandin in "nonresponder" patients. In the follow-up study, although the stimulatory effects of insulin on platelets from responder patients were improved to normal levels, the platelets from the nonresponder patients remained persistently unresponsive to the effect of the hormone.
Impairment of sequences of memory-guided saccades after supplementary motor area lesions. Different paradigms of saccades were recorded electro-oculographically in 2 patients with infarction affecting the left supplementary motor area. Saccades made toward visual targets (visually-guided saccades) or away from them (antisaccades) were normal in both patients. Memory-guided saccades, made to the remembered position of a flash occurring 2 seconds before, were preserved in 1 patient and only slightly impaired in the other. However, sequences of two or three memory-guided saccades were severely impaired in both patients. It has previously been reported that the supplementary motor area plays an important role in programming sequential limb movements. Our data suggest that this area plays a similar role in the control of sequential eye movements.