shukoor65/lab-rag-model huggingface dataset:
Effects of drive train stimulus intensity on ventricular refractoriness in humans. BACKGROUND. The strength-interval relation between the intensity of premature stimulus and the ventricular effective refractory period (VERP) has been well characterized. The effects of variation in the intensity of the basic drive train stimuli (S1) on VERP are not as well defined. This relation was studied in 44 patients undergoing clinically indicated electrophysiological study. METHODS AND RESULTS. The outputs of two stimulus isolation units were connected in parallel, allowing the intensity of S1 to be varied independently of intensity of the extrastimulus (S2). To prevent confounding effects from cycle length change, continuous overdrive pacing was performed for 3 minutes before each measurement of VERP. The effect of S1 intensity on VERP was assessed in 24 patients with S2 intensity kept constant at twice threshold. VERP shortened from 232 +/- 19 msec at an S1 intensity of 1.5 times threshold to 219 +/- 20 msec at 5 mA and 211 +/- 19 msec at 10 mA (p less than 0.0001 for baseline versus 5 mA and for 5 mA versus 10 mA). Autonomic blockade with atropine and propranolol blunted but did not completely eliminate this effect. To assess whether the effect of S1 intensity on VERP was independent of S2 intensity, S2 strength-interval curves were generated in 10 patients at low (1.5 times threshold) and high (10 mA) S1 intensities. All portions of the strength-interval curve were shifted to the left by an increase in S1 intensity. The time course of change in VERP after an abrupt increase in S1 intensity was assessed in an additional 10 patients. VERP changed slowly, requiring 18 +/- 28 seconds to shorten by 2 msec and 64 +/- 46 seconds to decrease by 10 msec after a change in S1 intensity from 1.5 times threshold to 10 mA. In a final group of 10 patients, VERP was measured using an eight-beat drive train and a 4-second intertrain interval. With this more conventional protocol, VERP shortened by 14 +/- 8 msec with an increase in S1 intensity from 1.5 times threshold to 10 mA. CONCLUSIONS. Increasing S1 intensity results in clinically significant, progressive shortening of VERP in man. This effect is independent of S2 intensity. The prolonged time course of the change in VERP after an increase in S1 intensity and the attenuation of this effect by autonomic blockade are consistent with stimulation of sympathetic nerve terminals and catecholamine release as a result of intense stimulation.
Detection of human papillomavirus DNA by in situ DNA hybridization and polymerase chain reaction in premalignant and malignant oral lesions. The sensitivity of detection of human papillomavirus (HPV) DNA in premalignant and malignant oral lesions by in situ hybridization (ISH) and polymerase chain reaction (PCR) were compared. With both methods HPV DNA was found in 4 of 24 cases of epithelial dysplasia, 4 of 14 cases of verrucous hyperplasia, and 1 of 10 cases of squamous cell carcinoma. The 10 cases of smokeless tobacco keratoses and 3 cases of verrucous carcinoma that we examined were all negative for HPV DNA. The PCR for the E6 open reading frame of HPV-16 correctly identified all cases that were positive by ISH. Only a single case that was positive by PCR was negative by ISH for HPV DNA. However, the PCR demonstrated the presence of HPV-16 infection in one case, which had hybridized most intensely with the probe for types 31/33/35 in the ISH. This discrepancy probably is due to the high degree of cross-hybridization in the ISH assay. PCR appears to be an effective technique for identifying HPV-16 DNA sequences in biopsy material from premalignant and malignant oral lesions.
Predictive testing for Wilson's disease using tightly linked and flanking DNA markers. We studied DNA polymorphisms for five new chromosome 13 markers in 52 Wilson's disease (WD) families from Europe, North America, and the Middle East. There was significant evidence for linkage between the Wilson's disease locus (WND) and all the marker loci. Multilocus linkage analysis, using a genetic linkage map established from reference pedigrees, suggested that WND is most likely between D13S31 and D13S59, at distances of 0.4 and 1.2 centimorgans, respectively. Our results suggest that the chromosomal location of the Wilson's disease gene is the same in all families from the populations studied. This evidence and the availability of many close, flanking, and polymorphic DNA markers make possible accurate and informative testing of potential carriers and WD homozygotes in families with at least one previously affected child. An advantage of a genetic linkage test over other laboratory methods for prediction of genotype in WD is that a reliable diagnosis can be made at a much earlier stage in life, including prenatally. In addition, DNA testing can be used in place of an invasive liver biopsy procedure to confirm a diagnosis in patients with borderline serum ceruloplasmin levels. Presymptomatic identification will also allow therapeutic intervention to prevent symptoms before irreparable liver or neurologic damage occurs. We describe the implementation of prenatal and preclinical diagnosis for two families with WD.
Endocrine manifestations of human immunodeficiency virus (HIV) infection. Endocrine manifestations of HIV infection include both pathological changes and disturbances in function. Mechanisms include direct infection of glands by HIV or opportunistic organisms, infiltration by neoplasms, side effects of drugs, and production of humoral factors that may alter metabolism. The adrenal gland is most often affected, but virtually every endocrine system may be involved. Dysfunction is often subtle, with symptoms overlapping those of the HIV infection itself. Endocrine manifestations may be found at any time in the course of the disease, from the asymptomatic HIV-positive stage through full-blown AIDS. Optimal management of these patients may include a careful search for, and appropriate treatment of, associated endocrine abnormalities.
Disease progression and viral genome variants in experimental feline leukemia virus-induced immunodeficiency syndrome [published erratum appears in J Acquir Immune Defic Syndr 1991;4(9):925] A fatal immunodeficiency syndrome with clinical and pathologic features similar to human AIDS is inducible in cats by experimental inoculation with a specific strain of feline leukemia virus (FeLV) called FeLV-FAIDS. The course of the feline disease is characterized by an age-dependent prodromal period during which a non-disease-specific, common form of proviral DNA is detected in bone marrow. Preceding clinical onset of immunodeficiency is production of high levels of specific, pathogenic variant genomes, primarily as unintegrated viral DNA, in bone marrow. Acute immunodeficiency syndrome (survival period approximately 3 months) is associated with a short prodromal period and appearance of a characteristic variant genome (variant A) that persists at high copy number as integrated and full-length unintegrated viral DNA in bone marrow. Chronic immunodeficiency syndrome (survival greater than 1 year) is marked by a longer prodromal period, a more gradual onset of severe clinical immunosuppression, and a predominance of other variant genomes that often contain substantial internal deletions. In both forms of the disease, tissue-specific replication of certain variant viruses is noted in the bone marrow, intestine, and lymph nodes. Evidence from in vitro and in vivo virus transmission studies indicates that the appearance of FeLV-FAIDS variant viruses reflects differential replication of viral genomes pre-existing in the inoculum rather than rapid de novo evolution of new variants within each animal. These results demonstrate that retrovirus-induced immunodeficiency disease in cats can be associated with and prefigured by the amplified replication of specific viral variants in target tissues.
Treatment of gram-negative peritonitis with aztreonam in patients undergoing continuous ambulatory peritoneal dialysis. In a multicenter open study, intraperitoneal aztreonam was used together with vancomycin, cloxacillin, or flucloxacillin for initial empiric treatment of peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD). Monotherapy with aztreonam was continued in 34 episodes of gram-negative peritonitis in 28 patients. The microorganisms isolated included Escherichia coli, Acinetobacter species, Pseudomonas species, and Klebsiella species. In three episodes, two organisms were cultured. Microbiologic assessment revealed cure in 27 episodes, cure with relapse in two, cure with superinfection in one, and treatment failure in four (with resistance to aztreonam in three). As assessed by clinical criteria, 27 episodes were cured, five failed to respond, and two responded partially. No adverse reactions to aztreonam were observed. Comparison of these 34 episodes with 35 episodes in historical controls (treated mainly with aminoglycosides and/or trimethoprim-sulfamethoxazole) showed significantly higher rates of cure (84% vs. 51%) and of survival (97% vs. 86%) as well as lower rates of catheter removal (65% vs. 87%) with aztreonam. Thus aztreonam is a safe and efficient agent for the treatment of peritonitis caused by gram-negative organisms in patients undergoing CAPD.
Quantitative magnetic resonance imaging in cervical carcinoma: a report on 30 cases. T1 and T2 relaxation times were calculated, before radiation therapy, in 30 patients with cervical carcinoma. Eight healthy young women were submitted to magnetic resonance imaging (MRI) to determine T1 and T2 times of the normal cervix. Magnetic resonance imaging was repeated, in 22 patients, during radiation therapy and at follow-up. During treatment and follow-up, patients with complete tumour response showed a significant T1 reduction compared with the pre-treatment values. With persistence of palpable or visible tumour, T1 times showed a small decrease during therapy, and a marked increase at subsequent examinations. The results suggest that the modifications of T1 times, during radiation therapy and follow-up, could be considered as a useful discriminant between patients with differing tumour response.
Prostaglandin F2 alpha and indomethacin in hepatogenic pulmonary angiodysplasia. Effects on pulmonary hemodynamics and gas exchange. We treated a 68-year-old man with cirrhosis of the liver associated with moderate hypoxemia. Contrast-enhanced echocardiography revealed late opacification of the left ventricle, and pulmonary perfusion imaging with 99mTc macroaggregated albumin showed evidence of a significant uptake in both lungs and in the liver, spleen, and kidneys. Right cardiac catheterization revealed pulmonary hypotension, low pulmonary vascular resistance, and high cardiac output. We administered prostaglandin F2 alpha intravenously (0.2 microgram/kg/min for 30 minutes) and indomethacin orally (75 mg/day for three days). There was some degree of resolution of the hypoxemia and increases in both pulmonary arterial pressure and pulmonary vascular resistance. These findings suggest that the pathophysiology of hepatogenic pulmonary angiodysplasia is a reversible intrapulmonary vascular dilatation. These conditions can to some extent be modulated by vasoactive substances such as prostaglandins or other eicosanoids.
Effect of dietary nucleotides on intestinal repair in rats with experimental chronic diarrhea. Nucleic acid synthesis in tissues of rapid growth is preferentially done using dietary purines and pyrimidines via the salvage pathway. In the case of a low protein intake, dietary nucleotides may be semiessential for cell replication of gut, lymphocytes, and bone marrow, and especially in those intestinal diseases in which the mucosa is altered, dietary nucleotides may have a role in intestinal development. The effect of dietary nucleotides on intestinal weight and length, gut mucosal weight, intestinal protein and DNA contents, and lactase, maltase, and intestinal mucosal activities was assessed in a controlled way. Weanling (21-day-old) rats were separated into two groups of 36, each receiving blindly a basal diet containing glucose polymers (C) or a basal diet with lactose as the main carbohydrate (L) for 15 days. Those fed with L developed a syndrome of chronic diarrhea and malnutrition. Ten rats of each group were sacrificed at that time. The rest of the animals of each group were separated into two subgroups. The first was fed with the C diet and the second with the C diet supplemented with 50 mg/100 g of each of the following nucleotides: AMP, GMP, CMP, UMP, and IMP (CN). Thus the subgroups CC, CN, LC, and LN were formed. Rats were sacrificed after 4 weeks and gut separated into three segments corresponding to duodenum, jejunum, and ileum. Analysis of variance was used to compare the effect of diet or segments. DNA and lactase, maltase, and sucrase activities increased in the LN group with respect to LC especially in jejunum and ileum but there were not any differences between CC and CN.
Hereditary coproporphyria: an imitator of multiple sclerosis. Hereditary coproporphyria can cause both peripheral neuropathy and central nervous system abnormalities. There are several similarities between multiple sclerosis and hereditary coproporphyria that are probably due to the central nervous system dysfunction present in both. This report describes a 62-year-old man with a five-year history of progressive paraparesis initially diagnosed as multiple sclerosis. Supporting evidence for the diagnosis of a demyelinating disease included three oligoclonal bands in the patient's cerebral spinal fluid, a prolonged visual evoked response bilaterally, abnormal sensory evoked potentials, and an area of increased signal in the posterior cervical cord suggestive of demyelination that was demonstrated on magnetic resonance imaging (MRI). Features atypical for multiple sclerosis were hypoactive deep-tendon reflexes, electromyographic evidence of peripheral neuropathy, and severe constipation. Elevated urine porphyrins and decreased levels of coproporphyrinogen oxidase confirmed the correct diagnosis of hereditary coproporphyria. The patient improved after being placed on a high-carbohydrate diet. Although central demyelination is known to occur in patients with porphyria, delayed evoked potentials and MRI abnormalities have not been previously reported.
Early postoperative basal serum GH level and the GH response to TRH in relation to the long-term outcome of surgical treatment for acromegaly: a report on 39 patients. During a 10-year period 39 patients with acromegaly, aged 23-73 years, underwent selective adenomectomy via a trans-sphenoidal or transfrontal (one case) approach. Six to 12 months after the operation, the serum level of growth hormone (GH) was reduced to less than 5 micrograms l-1 in 28 patients (74%) in at least two of three random samples and/or suppressed to less than 3 micrograms l-1 during an oral glucose load, thus fulfilling the commonly used criteria for a successful operation. In 10 patients these criteria for adequate GH reduction were not fulfilled, but their median S-GH level was reduced from 38 to 11 micrograms l-1 (P less than 0.01) after the operation. Surgery was successful in 11 of 13 (85%) patients with a microadenoma (less than 10 mm in diameter), in 10 of 14 (71%) patients with an adenoma of diameter greater than 10 mm but still enclosed in the sella, and in seven of 11 (64%) patients with locally invasive tumours. Impaired pituitary function was observed in 23% of the patients after surgery, independent of tumour size. In one patient the postoperative period was complicated by a lethal intracranial infection. During follow-up for 1-10 years, four patients relapsed, after 1, 1.5, 6 and 9 years, respectively. Patients for whom surgery appeared to have been ineffective at the evaluation 6-12 months postoperatively, or who later relapsed were identified by early (within 7 d) postoperative serum GH with a sensitivity of 90%. The accuracy for identification of a satisfactory outcome of surgery was 85%, and the predictive value was 90%. The corresponding values for the GH response to TRH measured 6-12 months postoperatively were 47, 40 and 54%, respectively. It is concluded that the basal level of serum GH measured 1-7 d postoperatively has higher sensitivity and specificity than the GH response to TRH 6-12 months postoperatively for evaluation of the effect of surgery on GH overproduction, and that it has a higher predictive power with regard to the long-term outcome of surgery for acromegaly.
Psychiatric aspects of chest pain in the emergency department. We estimate that a third of the patients who present to the ED with chest pain have a current psychiatric disorder and that psychiatric disorders among chest pain patients are associated with a high rate of ED utilization for chest pain evaluations. Physicians in the ED recognize only a small fraction of the psychiatric disorders, so appropriate treatment or referral may be infrequent. The proportion of chest pain patients with CAD who also have a psychiatric disorder may be in the range of 20% to 30%, justifying careful assessment of psychiatric disorders in CAD patients. We conclude that the psychiatric aspects of chest pain are sufficiently prevalent, clinically significant, and a contributor to unnecessarily high utilization of medical services. We call for clinical research to address these questions by outlining three areas of study that will advance our knowledge and care of the patient with chest pain.
Right ventricular hypertrophy detected by echocardiography in patients with newly diagnosed obstructive sleep apnea. We used polysomnography, echocardiography and ventilatory measurements to study 50 patients suspected of having OSA to determine a link to RVH. Twenty-eight patients (56 percent) had OSA and 20 (71 percent) of those had isolated RVH. We evaluated patients with RVH and divided them into two groups, those with apnea and those without apnea. The patients with sleep apnea were younger, weighed more, had greater BSA and had lower average oxygen saturations during the sleep study period. We divided the group with apnea into those with RVH and those without it. Those patients with RVH had a higher AI, longer average apnea time, a greater duration of longest apnea and a lower average oxygen saturation for the period of the sleep study. In addition, those with RVH had a lower average oxygen saturation during each apneic episode with a p value equaling 0.09.
Emergency laryngectomy. From 1974 to 1990, 31 patients underwent emergency laryngectomy for airway obstruction due to laryngeal carcinoma, in an effort to avoid the complication of stomal recurrence. This group of patients had a greater proportion of multiregional tumours (35 per cent vs 13 per cent) than a comparison group of elective laryngectomies. In other respects the two groups were similar. Early post-operative mortality (6.5 per cent vs 3 per cent), stomal recurrence rates (4.2 per cent vs 4.8 per cent) and survival (53 per cent vs 55 per cent) were not significantly different between the emergency laryngectomy group and the comparison group undergoing elective laryngectomy.
An autopsy case of I-cell disease. Ultrastructural and biochemical analyses. An autopsy case of I-cell disease in a 4-year-old Japanese girl is presented. In this report, the authors analyze the relationship between morphologic (including electron microscopic) and biochemical findings. Lymph node, spleen, and kidney, which were stained with Hale's colloidal iron method, contained large amounts of hexosamine. These substances had accumulated in lymphocytes of B-cell lineage.
The pediatrician's involvement in prevention and treatment of oral disease in medically compromised children. Significant oral health problems are associated with medical, physical, or mental disorders that occur in children. The pediatrician has the opportunity through early intervention to set the tone for a health care practice that will improve the quality of life for many disadvantaged children. When the pediatrician and pediatric dentist work hand in hand, the children can often expect a happy, healthy future.
The physiologic basis of diuretic synergism: its role in treating diuretic resistance. Diuretic drugs usually improve edema when used judiciously. Some patients, however, become resistant to their effects. Diuretic resistance may result from dietary indiscretion, poor compliance, impaired bioavailability, imparied diuretic secretion into the lumen of the renal tubule, or because other drugs interfere with diuretic activity. When easily treatable causes of diuretic resistance have been excluded, resistance often reflects the intensity of the stimuli to sodium retention. Recent experimental work has indicated ways in which the kidney adapts to chronic diuretic treatment and has indicated how these adaptations may limit diuretic effectiveness. First, nephron segments downstream from the site of diuretic action increase sodium-chloride (NaCl) reabsorption because the delivered NaCl load increases. Second, diuretic-induced contraction of the extracellular fluid volume stimulates kidney tubules to retain NaCl until the next dose of diuretic is administered. Third, kidney tubules themselves may become hypertrophic because they are chronically stimulated by diuretic-induced increases in NaCl delivery. These adaptations all increase the rate of NaCl reabsorption and blunt the effectiveness of diuretic therapy. When diuretic resistance is present, using a second diuretic drug that acts in a different nephron segment is often effective. Recent experimental results suggest that a second class of drug may act synergistically with the first by blocking the adaptive processes that limit diuretic effectiveness. On the basis of an understanding of the mechanisms of diuretic adaptation and resistance, treatment regimens can be designed to block specific adaptive mechanisms and to improve diuretic therapy.
Substance abuse: the designer drugs. Designer drugs, chemically altered compounds derived from federally controlled substances, have become a major cause of addiction and overdose deaths. These drugs include mescaline analogs, synthetic opioids, arylhexylamines, methaqualone derivatives and crack, a new form of cocaine. Sudden changes in mood, weight loss, depression, disturbed sleep patterns, deteriorating school or work performance, marital problems, and loss of interest in friends and social activities may be signs of drug addiction. Life-threatening complications of acute intoxication, such as hyperthermia, seizures, combative and psychotic behavior, and cardiorespiratory collapse, require prompt diagnosis and supportive intervention.
Differential expression of CD25 (interleukin-2 receptor) on lamina propria T cells and macrophages in the intestinal lesions in Crohn's disease and ulcerative colitis Many interleukin-2 receptor (CD25) bearing cells can be identified by alkaline phosphatase immunohistochemistry in the diseased intestinal lamina propria of children with Crohn's disease or ulcerative colitis, but rarely in normal intestine. In both diseases, the CD25+ cells are present as aggregates in the lamina propria below the epithelium, and constitute a large proportion of the lamina propria mononuclear cells. In Crohn's disease, but not ulcerative colitis, CD25+ cells are abundant in the submucosa. The CD25+ cells in Crohn's disease are 58-88% CD3+, CD4+, CD8-, indicating that they are T cells, whereas in ulcerative colitis the CD25+ cells are greater than 80% CD3-, CD4+, HLA-DR+, indicating that they are macrophages. Thus, differential expression of CD25 on T cells and macrophages serves to distinguish the immunologic lesions in ulcerative colitis and Crohn's disease.