123rc/medical_text huggingface dataset:
Two different point G to A mutations in exon 10 of the porphobilinogen deaminase gene are responsible for acute intermittent porphyria. Two mutations of the porphobilinogen (PBG) deaminase gene resulting in cross-reacting immunological material (CRIM) positive forms of acute intermittent porphyria (AIP) have been identified by in vitro amplification of cDNA and cloning of the amplified products in a bacterial expression vector. Both mutations resulted from G to A transitions in exon 10 of the gene and produced arginine to glutamine substitutions in the abnormal protein. Expression of mutant cDNA in Escherichia coli reveals that one but not the other of these amino acid changes results in a striking decrease of the optimal pH of the mutated enzyme. One or the other of these two mutations accounted for the defect causing AIP in six unrelated patients among the eight patients evaluated with the CRIM positive subtype of this disorder.
Hybridization protection assay: a rapid, sensitive, and specific method for detection of Philadelphia chromosome-positive leukemias. The Philadelphia (Ph1) chromosome is present in greater than 90% of patients with chronic myelogenous leukemia (CML) and in 2% to 20% of those with acute leukemias, for which it is an important prognostic marker too. The chimeric BCR-ABL mRNAs resulting from the translocation encode either a 210-Kd or a 190-Kd protein. The techniques used to detect Ph1 chromosome include karyotyping, Southern analysis to demonstrate bcr rearrangement, and polymerase chain reaction to amplify the BCR-ABL transcripts. However, the routine performance of these methods by clinical laboratories is cumbersome, time consuming, and exposes laboratory personnel to radioisotopes. We describe here the clinical application of a new method, the hybridization protection assay (HPA), which uses chemiluminescent acridinium-ester-labeled probes in conjunction with PCR for detection of the amplified BCR-ABL sequences. The method is sensitive, specific, and can reliably distinguish between the transcripts for P190BCR-ABL and P210BCR-ABL. In contrast to the 2 days or longer required for conventional hybridization, HPA analysis can be completed in less than 30 minutes. We have successfully used this method to analyze 60 leukemia samples (34 from Ph1-negative acute leukemias; 6 from Ph1-positive acute leukemias; and 20 from CML) with complete correlation (of BCR-ABL positivity or negativity) with the results of karyotype or Southern Blot analysis of genomic DNA for bcr rearrangement. Therefore, the HPA, in conjunction with PCR, appears to provide a rapid and reliable test for the diagnosis of Ph1-positivity.
Observer reliability in detecting surreptitious random occlusions of the monaural esophageal stethoscope. The esophageal stethoscope is used often during anesthesia to monitor ventilation and cardiac function. Deficiencies in observer vigilance may limit the effectiveness of this monitoring instrument. The aim of this study was to determine how long it took for an observer to detect a surreptitiously occluded monaural esophageal stethoscope in the setting of clinical anesthesia. During routine anesthesia, where an esophageal stethoscope was in use, a computer-guided device would artificially, silently, and at random time intervals, occlude the stethoscope tubing. Personnel using the stethoscope noted when they perceived the absence of stethoscope sounds. We studied 320 stethoscope occlusions in 32 patients. The time between stethoscope occlusion and detection was 34 +/- 59 seconds (mean +/- SD). Eighty-seven percent of detections were made in less than 60 seconds. However, 13% of detections were delayed for more than 60 seconds, and 2.3% for more than 240 seconds. While anesthesia personnel using an esophageal stethoscope could detect most stethoscope occlusions, failure to appreciate such episodes occurred in a small but significant number of cases. This suggests that the esophageal stethoscope has some definite limitations as a continuous monitor and that other monitoring techniques, such as oximetry, capnography, and ventilator disconnect alarms, as well as visual/tactile inspection of the patient, should be used as well.
Central nervous system involvement in Von Hippel-Lindau disease. Fifty individuals with Von Hippel-Lindau disease (VHL) were studied with gadolinium-enhanced magnetic resonance imaging (MRI) to determine the frequency and distribution of CNS lesions. The associated clinical features were also reviewed. Thirty-six (72%) of the 50 had 1 or more CNS tumors. The most frequently affected sites in the CNS excluding the retina were the cerebellum (52%), spinal cord (44%), and brainstem (18%). New regional predilections for the craniocervical junction and conus medullaris were demonstrated by this study. Forty-one percent of all VHL patients with CNS tumors were neurologically asymptomatic: cerebellar tumors (50%), spinal cord tumors (50%), and brainstem tumors (44%) were often without clinical signs or symptoms. Multiple lesions were common. The mean age of all VHL patients (34.5 years) was similar to the mean age of all CNS VHL patients (34.4 years), suggesting a lack of age association. CNS lesions commonly occurred in the 2nd decade of life. All patients at risk for VHL should be evaluated using gadolinium-enhanced MRI after 10 years of age, although ophthalmic examination should be initiated within the 1st 2 years of life. Enhanced MRI is particularly useful in the detection of CNS tumors in patients with the VHL gene.
Involvement of thromboxane and neutrophils in multiple-system organ edema with interleukin-2. Interleukin-2 (IL-2) produces toxicity characterized by generalized edema within 24 hours. This study tests whether the rate of IL-2 administration modulates the onset of edema and examines thromboxane (Tx) and neutrophils as possible mediators of this event. Recombinant human IL-2, 10(5) U (n = 7), 10(6) U (n = 9), or vehicle (n = 8) were given to anesthetized rats intravenously during a period of 1 hour. At 6 hours edema, as measured by increase in wet to dry weight (w/d) ratio, was present in the heart, liver, and kidney, with 10(5) U IL-2 and in the lung, heart, liver and kidney, with 10(6) U IL-2, relative to values with vehicle-infused controls (all p less than 0.05). With a 1-hour infusion of 10(6) U IL-2, there was an increase in plasma thromboxane (Tx)B2 level to 1290 +/- 245 pg/mL, higher than 481 +/- 93 pg/mL in control rats (p less than 0.05); lung polymorphonuclear leukocyte (PMN) sequestration of 53 +/- 7 PMN/10 higher-power fields (HPF) relative to 23 +/- 2 PMN/10 HPF in controls (p less than 0.05); and increased bronchoalveolar lavage (BAL) fluid protein concentration of 1970 +/- 210 micrograms/mL relative to 460 micrograms/mL in controls (p less than 0.05). When 10(6) U IL-2 was given as a 1-minute intravenous bolus (n = 9), edema was not demonstrated, plasma TxB2 levels were similar to controls, there was no leukosequestration, and BAL protein levels were normal. These data indicate that a constant infusion but not the rapid bolus administration of IL-2 produces in rats multiple-system organ edema, increased plasma TxB2, sequestration of PMNs, and microvascular permeability. These findings may explain the early toxicity seen in patients given high-dose IL-2 in cancer treatment.
Demonstration of an area of slow conduction in human atrial flutter. Ten patients with chronic atrial flutter were studied prospectively using electrophysiologic mapping and pacing techniques to assess the mechanism of atrial flutter and the presence of an area of slow conduction in the atria. Electrograms recorded from greater than or equal to 30 right atrial sites for each patient during atrial flutter demonstrated that right atrial free wall activation was craniocaudal and that the interatrial septum activation was caudocranial, consistent with a reentrant circuit involving the right atrium. In six patients, slow conduction occurred during atrial flutter in the inferior right atrium and was spatially associated with fractionated electrographic recordings. In the other four patients, a "missing" interval of electrical activity occurred in the inferior right atrium for an average of 40% of the atrial flutter cycle. Transient entrainment criteria were demonstrated in each patient during rapid high right atrial pacing. The mean activation time from the high right atrial pacing site to the coronary sinus (inferior left atrial) recording site was long (228 ms) and consistent with activation through an area of slow conduction. During rapid pacing of atrial flutter from the coronary sinus site, no transient entrainment criteria could be demonstrated. The mean activation time from the coronary sinus pacing site to the high right atrial recording site was relatively short (134 ms) and consistent with orthodromic activation of the high right atrium not through an area of slow conduction. High right atrial pacing during sinus rhythm at rates similar to atrial flutter demonstrated a short activation time to the coronary sinus and low right atrial sites (mean 169 and 88 ms, respectively), indicating activation that did not traverse an area of slow conduction. Coronary sinus pacing during sinus rhythm demonstrated the same phenomena. Low right atrial electrograms recorded during sinus rhythm and during rapid pacing of sinus rhythm were not fractionated, although they were during atrial flutter. Thus, atrial mapping and pacing data were complementary, indicating that human atrial flutter in the patients studied was generated by a reentrant circuit in the right atrium, with an area of slow conduction in the low right atrium present only during atrial flutter.
Infection during chronic epidural catheterization: diagnosis and treatment. A potentially serious complication of long-term epidural catheterization in cancer patients is infection. The early signs of infection were studied in 350 patients in whom long-term epidural catheters were inserted. Three areas of the catheter track were found to be involved; exit site and superficial catheter track infection, and epidural space infection. The authors identified the early signs of infection in each area and the progress of the infection from the deep track to include the epidural space in four of these patients. All 19 patients who developed deep track or epidural infections were successfully treated with antibiotics and catheter removal. None of the patients required surgery for spinal cord decompression. Catheters were replaced in 15 of the 19 treated patients who requested them after treatment with no recurrent infections. It was concluded that use of long-term epidural catheterization is associated with a definable epidural infection rate. The use of epidural opioid analgesia is an effective and safe means of obtaining pain relief for terminally ill patients when patients are monitored for possible infection and receive prompt treatment when the diagnosis is established.
The emergence of hepatitis B as a sexually transmitted disease. In the United States, approximately 300,000 cases of hepatitis B virus infection occur annually, and heterosexual activity is one of the most commonly reported risk factors for acquiring disease. Until the number of infections transmitted through heterosexual contact can be reduced through hepatitis B vaccination, there is little chance of controlling this infection.
Ischemia and reperfusion during intermittent coronary occlusion in man. Studies of electrocardiographic changes and CPK release. The course of 357 balloon inflations performed during 38 angioplasties for single-vessel coronary artery disease was prospectively studied using continuous ECG recording. Ischemic ECG changes appeared during 91 percent of the inflations at a mean of 20 +/- 8 seconds after inflation and resolved in 97 percent of those at a mean of 11 +/- 5 seconds after deflation. Elevation of the plasma CPK level was found in six patients who had ischemic ECG changes for at least 7.8 minutes. The duration of ischemia did not exceed 5.4 minutes in any of the patients without CPK elevation. Resolution of the ischemic changes was delayed in patients with CPK elevation and in last vs initial inflations. We conclude that in patients with noninfarcted myocardium, ECG changes follow coronary occlusion and reflow very rapidly, detecting these coronary events with a high sensitivity. Lack of rapid regression predicts lack of reperfusion, and persistence of ischemia for more than 7.8 minutes is sufficient to cause myocardial necrosis.
Tarsal tunnel syndrome. Causes and results of operative treatment. From 1975 to 1988, operative treatment was performed on 50 feet in 45 patients with tarsal tunnel syndrome. The causes of this syndrome were correlated with operative findings and included ganglia in 18, and a bony prominence from talocalcaneal coalition in 15. Five feet had sustained an injury, tumours were found in three and there was no obvious cause in nine. In most cases in need of operative treatment, there was a space-occupying lesion. Classifying the results according to causes, those with coalition or a tumour fared better, and idiopathic and traumatic cases had a worse outcome. In cases with a definite lesion, an excellent result can be expected from surgical treatment carried out soon after onset of the condition.
Sensitivity of exercise electrocardiography for acute cardiac events during moderate and strenuous physical activity. The Lipid Research Clinics Coronary Primary Prevention Trial. We determined whether the exercise electrocardiogram predicted acute cardiac events during moderate or strenuous physical activity among 3617 asymptomatic, hypercholesterolemic men (age range, 35 to 59 years) who were followed up in the Coronary Primary Prevention Trial. Submaximal exercise test results were obtained at entry and at annual follow-up visits in years 2 through 7. ST-segment depression or elevation (greater than or equal to 1 mm or 10 microV-sec) was considered to be a positive test result. The circumstances that surrounded each nonfatal myocardial infarction and coronary heart disease death were determined through a record review. The cumulative incidence of activity-related acute cardiac events was 2% during a mean follow-up period of 7.4 years. The risk was increased 2.6-fold in the presence of clinically silent, exercise-induced, ST-segment changes at entry (95% confidence interval [Cl], 1.3 to 5.2) after adjustment for 11 other potential risk factors. Of 62 men who experienced an activity-related event, 11 had a positive test result at entry (sensitivity, 18%; 95% Cl, 8 to 27). The specificity of the entry exercise test was 92% (95% Cl, 91 to 93). The sensitivity and specificity were similar when the length of follow-up was restricted to 1 year after testing. For a newly positive test result on a follow-up visit, the sensitivity was 24% (95% Cl, 12 to 36), and the specificity was 85% (95% Cl, 84 to 86); for any positive test result during the study (mean number of tests per subject, 6.2), the sensitivity was 37% (95% Cl, 25 to 49), and the specificity was 79% (95% Cl, 77 to 80). Our findings suggested that the presence of clinically silent, exercise-induced, ischemic ST-segment changes on a submaximal test was associated with an increased risk of activity-related acute cardiac events. However, this test was not sensitive when used to predict the occurrence of activity-related events among asymptomatic, hypercholesterolemic men. For this reason, the utility of the submaximal exercise test to assess the safety of physical activity among asymptomatic men at risk of coronary heart disease is likely to be limited.
Neuro-imaging and positron emission tomography of congenital homonymous hemianopsia. Congenital homonymous hemianopsia is an uncommon asymptomatic visual field defect discovered typically in young adult life that is caused by a diverse group of insults to the retrochiasmal afferent visual system occurring prenatally, at birth, or during early childhood. We treated eight patients with congenital homonymous hemianopsia; seven with damage involving the optic radiations and one with an abnormality of the optic tract. We performed positron emission tomography using 18F-fluoro-2-deoxyglucose on two patients with dense homonymous hemianopsias, lesions of the contralateral optic radiations, and largely intact occipital cortex. These studies showed minimal abnormalities in resting visual cortex glucose metabolism of the affected visual cortex.
Thyroglobulin level as a predictive factor of tumoral recurrence in differentiated thyroid cancer. Ninety-eight patients with differentiated thyroid carcinoma were studied. Actuarial methods were used to investigate the 10-yr probability of survival (pS) and disease-free survival (pDFS). Our results show that the pDFS is a function of: (1) clinicopathologic stage: Stages I-II, pDFS = 90.9% +/- 5.0% versus Stages III-IV, pDFS = 55.9% +/- 17.8% (p less than 0.005); (2) age: Age less than 45 yr, pDFS = 87.2% +/- 10.0% versus age greater than or equal to 45 yr, pDFS = 66.6% +/- 12.0% (p less than 0.002); and (3) plasma thyroglobulin (Tg) levels: Tg less than or equal to 23 ng/ml, pDFS = 100% versus Tg greater than 23 ng/ml, pDFS = 68.3% +/- 10.6% (p less than 0.005). Using the multivariate analysis of proportional risk, the regression coefficients obtained (Stage: beta = 0.7615; Age: beta = 1.6398, and Tg: beta = 1.7607) allowed us to establish two different groups of risk of relapse on the basis of a prognostic index.
Differential effects of continuous versus intermittent suction on tracheal tissue. The purpose of this study was to determine the differential effect of continuous versus intermittent application of negative pressure on tracheal tissue during endotracheal suctioning. The sample consisted of 12 mongrel dogs, randomly assigned to group 1 (N = 5), continuous suction, or group 2 (N = 5), intermittent suction. All animals were orally intubated (40F endotracheal tube). Two control animals were intubated and not suctioned. Animals in group 1 and 2 were suctioned every 15 minutes for 4 hours for a total of 16 suction passes. Endotracheal suctioning was performed by using a 14F suction catheter either continuously (10 seconds) or intermittently (2 seconds with, 1 second without for a total of 10 seconds) at a suction pressure of 200 mm Hg and a suction flow rate of 16 L/min. Tracheal tissue samples were examined for simplified and major simplified damage, ulceration, and ulceration with necrosis. Results indicated that all forms of damage were present with both suctioning techniques. No significant differences were found between group 1 and group 2 (Wilcoxon rank sum) for any of the alterations. Results indicate that both continuous and intermittent application of negative pressure with endotracheal suction produces significant damage to tracheal tissue.
Angiosarcoma of the uterus: a case report. We are reporting a case of angiosarcoma of the uterus in which the diagnosis was confirmed ultrastructurally by demonstration of Weibel-Palade bodies in the tumor cells. Only 10 cases of this entity have been previously documented in the literature.
Lewis system alterations in gastric carcinogenesis. Alterations in the expression of type 1 blood group-related antigens (Lewis a and b) were examined immunohistochemically in 371 consecutives gastric biopsy and 80 surgical specimens from patients of gastric carcinoma. The ABH and Lewis phenotype and secretor status of the patients were correlated with histologic findings. An anomalous expression of Lewis a antigen was found in 88 of 249 gastric biopsy specimens of Lewis (a-b+) phenotype patients. The prevalence of this anomaly increased with the evolution of the premalignant process, in agreement with the commonly accepted model of gastric carcinogenesis. Thus, anomalous Lewis a antigen appeared in 66.6% of gastric dysplasia cases, in 64.6% of intestinal metaplasia, in 15.4% of atrophic gastritis, and in 7.4% of superficial gastritis. No alterations were found in subjects with normal gastric mucosa. Forty-seven of the 49 Lewis (a-b+) phenotype gastric carcinoma patients showed antigenic alterations in tumor cells (anomalous Lewis a antigen in 36 and loss of Lewis antigens in 11). In 26 of these gastric specimens an anomalous Lewis a antigen was present in areas of intestinal metaplasia and/or dysplasia away from the area of neoplastic transformation. The expression of Lewis a antigen in Lewis (a-b+) phenotype patients is a frequent phenomenon in gastric neoplastic cells and could result from the blocked synthesis of Lewis b antigen with accumulation of its precursors. These findings suggest that, during gastric carcinogenesis, antigenic alterations may precede neoplastic transformation. An anomalous Lewis a antigen could constitute a significant index of severity of the histologic lesion and contribute to identifying high-risk individuals.
Reentrant ventricular arrhythmias in the late myocardial infarction period: mechanism by which a short-long-short cardiac sequence facilitates the induction of reentry. The electrophysiological mechanism by which a short-long-short stimulated cardiac sequence facilitates the induction of ventricular tachyarrhythmia was investigated in dogs 4 days after ligation of the left anterior descending coronary artery. In these dogs, reentry develops in the surviving electrophysiologically abnormal epicardial layer that overlies the infarct zone when premature stimulation results in a critically long arc of functional conduction block. The activation wavefront circulates around both ends of the arc, coalesces, and conducts slowly distal to the arc before reactivating sites proximal to the arc to initiate a figure-eight reentrant circuit. Epicardial isochronal activation maps and effective refractory periods (ERPs) were determined during three different stimulation protocols: A, a basic train of eight beats at a cycle length of 300 msec followed by a single premature stimulus (S2); B, a basic train of eight beats at a cycle length of 300 msec with abrupt lengthening of the last cycle of the train before S2 to 600 msec; C, a basic train of eight beats at a cycle length of 600 msec followed by S2. Protocol B was found to result in a differential lengthening of ERP at adjacent sites within the border of the epicardial ischemic zone, whereas protocols A and C induced, respectively, comparable shortening and lengthening of ERPs at the same sites. The differential lengthening of ERPs at adjacent sites resulted in an increased dispersion of refractoriness so that a premature stimulus induced functional conduction block between those sites. The development of a longer arc of conduction block and, hence, a longer reentrant pathway as well as slower conduction of the circulating wavefront during protocol B allowed more time for refractoriness to expire proximal to the arc and for the circulating wavefront to reexcite those sites to initiate reentry. The lengthening of ERP, associated with a single long cycle (protocol B), ranged from 44% to 79% of the total increase in ERP after a series of eight long cycles (protocol C). Epicardial sites with longer ERPs located close to the center of the ischemic zone showed more lengthening of refractoriness during protocol B compared with more normal sites near the border of the ischemic zone. This strongly suggests that the increased dispersion of refractoriness during protocol B is caused by the shorter memory of ischemic myocardium to the cumulative effects of preceding cycle lengths.
Intussusception encephalopathy: an underrecognized cause of coma in children. Intestinal intussusception is a common cause of bowel obstruction in infancy and early childhood. Typically the presenting signs and symptoms are referable to the abdomen. On occasion the most prominent presenting feature is depressed level of consciousness. We describe 3 patients who presented with coma associated with intussusception.