shukoor65/lab-rag-model huggingface dataset:
Expiratory muscle fatigue in normal subjects. We examined expiratory muscle fatigue during expiratory resistive loading in 11 normal subjects. Subjects breathed against expiratory resistances at their own breathing frequency and tidal volume until exhaustion or for 60 min. Respiratory muscle strength was assessed from both the maximum static expiratory and inspiratory mouth pressures (PEmax and PImax). At the lowest resistance, PEmax and PImax measured after completion of the expiratory loaded breathing were not different from control values. With higher resistance, both PEmax and PImax were decreased (P less than 0.05), and the decrease lasted for greater than or equal to 60 min. The electromyogram high-to-low frequency power ratio for the rectus abdominis muscle decreased progressively during loading (P less than 0.01), but the integrated EMG activity did not change during recovery. Transdiaphragmatic pressure during loading was increased 3.6-fold compared with control (P less than 0.05). These findings suggest that expiratory resistive loaded breathing induces muscle fatigue in both expiratory and inspiratory muscles. Fatigue of the expiratory muscles can be attributed directly to the high work load and that of the inspiratory muscles may be related to increased work due to shortened inspiratory time.
Interferon-alpha overrides the deficient adhesion of chronic myeloid leukemia primitive progenitor cells to bone marrow stromal cells. Primitive blast colony-forming cells (BI-CFC) from chronic myeloid leukemia (CML) patients are defective in their attachment to bone marrow-derived stromal cells compared with normal BI-CFC. We investigated the effect of recombinant interferon-alpha 2a (IFN-alpha) on this interaction between hematopoietic progenitor cells and bone marrow-derived stromal cells by culturing normal stromal cells with IFN-alpha (50 to 5,000 U/mL). At 50 U/mL we found that: (1) the capacity of stromal cells to bind two types of CML primitive progenitor cells (BI-CFC and long-term culture-initiating cells) was increased; and (2) the amount of sulfated glycosaminoglycans (GAGs) in the stromal layer was increased. However, sulfated GAGs were not directly involved in binding CML BI-CFC, unlike binding by normal BI-CFC, which is sulfated GAG-dependent. Neuraminidase-treated control stromal cells bound an increased number of CML BI-CFC, reproducing the effect of IFN-alpha, whereas the binding to IFN-alpha-treated stromal cells was unaffected by neuraminidase treatment. Thus, the enhanced attachment by primitive CML progenitor cells to INF-alpha-treated stromal cells might be due to changes in the neuraminic acid composition in the stromal cell layer. Our in vitro evidence may provide insights into the mechanism of action of IFN-alpha in vivo. Prolonged administration may alter the marrow microenvironment in some patients such that it can restrain the aberrant proliferation of Philadelphia chromosome (Ph)-positive stem cells while permitting Ph-negative stem cells to function normally.
Diffuse uterine leiomyomatosis with hemorrhage. A 28-year-old woman with primary infertility and severe menorrhagia underwent a hysterectomy after failed hormonal therapy for multiple leiomyomas. The postoperative pathologic findings established the diagnosis of diffuse uterine leiomyomatosis, which demonstrated histologic, immunohistochemical, and ultrastructural similarity to leiomyomas of the uterus. The rapid growth of the tumor coincided with the administration of clomiphene citrate, an estrogenic agonist. As with the common leiomyoma, intralesional hemorrhage in this case of diffuse leiomyomatosis was associated with norethindrone acetate treatment given after the cessation of clomiphene therapy.
Effectiveness of glibenclamide on myocardial ischemic ventricular arrhythmias in non-insulin-dependent diabetes mellitus. Glibenclamide, a hypoglycemic sulfonylurea, is a blocker of the adenosine triphosphatase-modulated potassium ion channels. The opening of these channels in the myocardial cells, induced by acute myocardial hypoxia, can be responsible for ischemic ventricular arrhythmias. To evaluate the antiarrhythmic effects of this drug 19 non-insulin-dependent diabetic patients were selected. They had coronary artery disease and evidence on Holter monitoring of ventricular premature complexes or nonsustained ventricular tachycardia, or both, induced by transient myocardial ischemia. In all patients, 24-hour electrocardiographic monitoring was performed to evaluate the number and duration of myocardial ischemic events, the frequency of ventricular premature complexes and nonsustained ventricular tachycardia per minute of ischemia and the percentage of ventricular premature complexes versus total ischemic beats. Selected patients were classified in 2 groups: group A (9 patients) received metformin (placebo) and group B (10 patients) was treated with glibenclamide. On the fourteenth day patients underwent 24-hour control monitoring. Then a crossover between the 2 groups was made and a new Holter monitoring sequence was performed at the end of the second phase. Results indicate that glibenclamide significantly (p less than 0.001) reduced both the frequency of ventricular premature complexes and the episodes of nonsustained ventricular tachycardia during transient myocardial ischemia, but did not change the number and duration of acute myocardial ischemic attacks and did not reduce the spontaneous ventricular arrhythmias. Thus, glibenclamide appears to have an antiarrhythmic effect in preventing ventricular arrhythmias induced by transient myocardial ischemia.
AAEM minimonograph #11: Needle examination in clinical electromyography. The physiologic and histologic principles underlying clinical electromyographic studies are briefly reviewed as an introduction to the normal and abnormal findings in human subjects. Technical aspects of recordings as well as the specific types of discharges and their significance are discussed.
Importance of chloride in the development of salt-induced angiotensin II hypertension in rats. This study attempted to evaluate the effect of anion associated with sodium loading on the development of angiotensin II (AII)-induced hypertension in rats. Hypertension was induced by intraperitoneal infusion of AII(125 ng/min) for 12 days via miniosmotic pump (systolic blood pressure on day 12, 143 +/- 3 mm Hg). High dietary intake of sodium chloride significantly augmented the AII-induced hypertension (systolic blood pressure on day 12, 166 +/- 4 mm Hg), but equimolar sodium loading provided as sodium citrate failed to enhance AII hypertension (systolic blood pressure on day 12, 136 +/- 8 mm Hg). Thus, the data suggest that the full expression of salt (NaCl) sensitivity in AII hypertension depends on high dietary intake of both sodium and chloride.
Augmentation of reverse arthus reaction by mast cells in mice. Immune complex-induced injury is an important pathogenic factor in antibody-mediated nephritis, systemic lupus erythematosus, rheumatoid arthritis, and other diseases. In this study we investigated the role mast cells in immune complex-mediated injury in mouse skin. Reverse Arthus reaction was induced in mast cell-deficient WBB6F1-W/Wv mice and their congenic controls (WBB6F1(-)+/+). Serial skin sections were evaluated for neutrophil infiltration, edema, and hemorrhage. In WBB6F1-W/Wv mice the neutrophil influx was only 40% and edema 60% of that in congenic controls. Hemorrhage was also significantly reduced in the mast cell-deficient mice. After mast cell reconstitution, the magnitude of the reaction in WBB6F1-W/Wv was equivalent to that in WBB6F1(-)+/+ mice. Mast cell release in reverse Arthus reaction was evaluated by measuring fluorescence intensity after avidin-FITC staining of mast cell granules. There was a 70% decrease in fluorescence intensity. The 5-lipoxygenase inhibitor A-63162 significantly decreased neutrophil accumulation (40%), edema (60%), and hemorrhage in WBB6F1(-)+/+, but not in mast cell-deficient mice. Mast cell reconstitution of WBB6F1-W/Wv mice restored the effect of A-63162. The results indicate that mast cells and their mediators, including leukotrienes, make an important contribution to reverse Arthus reaction.
The significance of myoclonic status epilepticus in postanoxic coma. We report 11 adults who exhibited myoclonic status epilepticus (MSE) after cardiac arrest. Based on pathologic, electroencephalographic, and clinical evidence, we conclude that our patients died from the initial anoxic-ischemic insult rather than as a result of MSE. We suggest that the seizures in these nonsurvivors were self-limited events arising from lethal damage to neurons. Thus, in patients with bilaterally synchronous facial myoclonus, bilateral loss of pupillary or oculovestibular reflexes, and suppression and burst-suppression on EEG, it is not warranted to use anesthetic barbiturates to treat MSE.
Distribution of carbon flux within fatty acid utilization during myocardial ischemia and reperfusion. Twenty-nine intact, working pig hearts were extracorporeally perfused and divided into two study groups (16 Aerobic and 13 Ischemic/Reflow hearts). Step function, equilibrium labeling with [14C]palmitate was used to develop uptake and washout curves of radioactive fatty acid products contained in coronary effluent during either aerobic perfusion or reperfusion after ischemia (60% reduction in left anterior descending coronary flow for 30 minutes). Left anterior descending control flows were slightly overperfused in Aerobic hearts (18% higher than in Ischemic/Reflow hearts); otherwise, circumflex and right coronary flows, left ventricular pressure, and serum fatty acids and blood sugar levels were comparable between groups. As expected in Ischemic/Reflow hearts, recovery of regional systolic shortening and myocardial oxygen consumption in reperfusion was only modestly impaired (-20% and -19%, respectively, not significant and p less than 0.011 compared with preischemic values, not significant from Aerobic hearts). The only significant metabolized product to be released from labeled fatty acid utilization in either group was 14CO2. A smaller fatty acid pool also was measured and accounted for by that contained in the coronary intravascular volume. We could determine no significant back diffusion of fatty acids from myocardium in either perfusion condition. Uptake time constants of the early phase of 14CO2 production also were virtually identical in both groups (19.9 +/- 3.2 versus 16.7 +/- 3.2 minutes in Aerobic and Ischemic/Reflow hearts, respectively) and strongly correlated with hemodynamics as described by heart rate. In washout studies, tissue radioactivity in the aqueous soluble and fatty acid pools declined in both study groups, and counts in complex lipids and cholesterol/cholesteryl esters remained steady, whereas those in triacylglycerols varied. Washout of 14CO2 in both groups never reached background radioactivity over a 40-minute sampling after cessation of isotope infusion into the perfusate, suggesting slow release of trapped substrate from intracellular pools, which then proceeded to fatty acid oxidation. In conclusion, these experiments have demonstrated very similar findings with respect to fatty acid uptake, storage, and release characteristics between aerobic and reperfused myocardium. We found no differences in preferred substrate utilization and oxidation as a result of reversible ischemia followed by reflow.
Transantral sphenoethmoidectomy: a procedure for the 1990s? Currently, among otolaryngologists, much attention is focused on the surgical management of paranasal sinus disease. However, transantral sphenoethmoidectomy is rarely mentioned in the literature of the past several decades. We reviewed a consecutive series of 98 patients over a 12-year period who underwent transantral sphenoethmoidectomy in the treatment of severe chronic hyperplastic pansinusitis. The major and minor complications encountered are tabulated, as are the clinical outcomes. A description of the operative technique is followed by a discussion of the indications for this approach. We believe transantral sphenoethmoidectomy has a useful place in modern paranasal sinus surgery.
Deliberate hypotension with nicardipine or nitroprusside during total hip arthroplasty. To induce deliberate hypotension during anesthesia, nicardipine was administered to patients undergoing total hip arthroplasty and was randomly compared with nitroprusside. Hemodynamic measurements were performed before and 10, 20, 30, and 60 min after starting to administer either nicardipine (n = 12) or nitroprusside (n = 12) (B, T1, T2, T3, and T4, respectively); at the end of drug infusion (T5); and 10, 20, and 60 min later (T6, T7, and T8, respectively). Plasma renin activity and catecholamine levels were measured at B, T1, T5, T6, and T7. In addition, plasma nicardipine concentration was measured in five patients at T1, T2, T5, T7, and T8. As with nitroprusside, nicardipine administration (1-3 micrograms.kg-1.min-1, after a titration dose of 4.7 +/- 1.5 mg) resulted in hypotension (up to -34% +/- 3%), a decrease in systemic vascular resistances (up to -49% +/- 4%), and increases in heart rate (up to +17% +/- 6%), cardiac index (up to +37% +/- 8%), plasma norepinephrine (up to +63% +/- 17%) and epinephrine (up to +232% +/- 68%) levels, and plasma renin activity (up to +336% +/- 207%). Ten and 20 minutes after discontinuation of the hypotensive drug, nicardipine led to persistent vasodilation and hypotension, which differed significantly from the hypertensive rebound observed after nitroprusside discontinuation, despite a similar increase in plasma renin activity and catecholamine levels. Our results indicate that after the infusion was terminated, the nicardipine-induced vasodilation was opposed to the vasoconstrictive effects of angiotensin II and catecholamines, thus avoiding hypertensive rebound.
PTA and laser assisted PTA combined with simultaneous surgical revascularization. In this study we investigated the efficacy of percutaneous transluminal angioplasty (PTA) and laser percutaneous transluminal angioplasty (LPTA) as an adjunct to surgery in patients with peripheral vascular disease. We report 84 cases of the simultaneous association of direct arterial surgery and angioradiological procedures to treat 82 patients with arterial occlusive disease of the lower limbs. Sixty-five patients (79.2%) were affected by severe claudication and 14 (19.6%) presented with rest pain or gangrene. One patient (1.2%) had signs of acute ischemia. PTA or LPTA were utilized as an inflow procedure in 41 cases (48.8%), as an outflow procedure in 24 (28.6%) and in 19 cases (22.6%) to recanalize an arterial occlusion in the contralateral limb opposite to surgical interventions. Immediate postoperative patency was achieved in 79 cases (94.0%), while in 5 cases (6.0%) it was impossible to perform a satisfactory balloon dilatation. The complication rate was 16.6%: 10 perioperative thromboses, 1 plaque dissection, 1 peripheral embolus, 1 haemorrhage and 1 femoral nerve lesion. No perioperative mortality occurred in this group of patients. Long term patency, analyzed with the life-table method (mean follow-up: 28 months) was respectively 78.0%, 76.3% and 78.9% at 5 years. These data indicate that the combined revascularization technique should always be recommended in properly selected patients because it is less invasive, the surgical risk and operative time are reduced and associated with early and long term cumulative patency rates comparable to those of extensive surgery.
Study of P wave morphology in lead V1 during supraventricular tachycardia for localizing the reentrant circuit. Paroxysmal supraventricular tachycardia (SVT) is a benign form of tachycardia that generally does not require costly evaluation. The purpose of this study was to describe a new sign permitting delineation of the mechanism of SVT by analysis of the P wave in lead V1 and the left atrial electrogram, which may be registered by the esophageal electrode. Among 146 patients with SVT, 72 had a ventriculoatrial interval greater than 70 msec. The P wave in lead V1 during SVT was discernible in 69 of them. The precession of the left atrial electrogram on the P wave in lead V1 was always associated with reentry through a left lateral (n = 37) or posteroseptal (n = 4) accessory atrioventricular (AV) connection. When the P wave in lead V1 preceded or occurred simultaneously with the left atrial electrogram, reentry was through either the AV node or a right-sided accessory AV connection. On the other hand, although the P wave in lead V1 was more frequently negative in reentry through a right-sided connection and positive in reentry through a left-sided connection, the polarity was not specific enough to identify the reentry. The precession of the left atrial electrogram recorded by the esophageal electrode on the P wave in lead V1 during SVT was a specific criterion of reentry through a left accessory AV connection, and this technique could be useful for preliminary localization of the accessory connection before electrophysiologic study.
Hyperdynamic circulation in a chronic murine schistosomiasis model of portal hypertension. Chronic murine schistosomiasis is a natural disease model of portal hypertension closely mimicking the clinical and histological features of human hepatic schistosomiasis. We studied the splanchnic and systemic hemodynamics in the murine model of schistosomiasis by radioactive microsphere technique. Mice infected with 60 cercariae of Schistosoma mansoni (n = 8) were studied hemodynamically 11 wk after the infection and were compared with age-matched healthy controls (n = 11). Mean portal venous inflow in the infected mice (3.82 +/- 0.32 ml/min) was 61% higher than in the healthy animals (2.37 +/- 0.25 ml/min; p less than 0.01). A twofold increase in hepatic arterial flow was also seen in mice with schistosomiasis (0.47 +/- 0.14 ml/min) as compared with controls (0.16 +/- 0.03 ml/min; p less than 0.05), whereas splanchnic arteriolar resistance (60.91 +/- 7.64 vs. 101.21 +/- 11.06 mm Hg.min.ml-1.gm; p less than 0.05) and peripheral vascular resistance (112.05 +/- 14.05 vs 254.53 +/- 29.86 mm Hg.min.ml-1.gm; p less than 0.01) were reduced. There was a significant increase in cardiac index (752 +/- 99 vs. 453 +/- 55 ml.min-1.kg body weight-1; p less than 0.05) and reduction in mean arterial pressure (81.37 +/- 3.09 vs. 101.45 +/- 5.85 mm Hg; p less than 0.05) in the infected animals compared with controls. These observations clearly demonstrate the existence of a hyperdynamic circulatory state in this model of portal hypertension.
Role of adjuvant therapy in colorectal cancer. After nearly three decades of consistently disappointing adjuvant therapy trials in resectable colorectal cancer, recently emerging results offer some basis for cautious optimism. Adjuvant fluorouracil-containing regimens appear to confer a modest treatment benefit in completely resected colonic adenocarcinomas. The two most promising chemotherapy approaches at present appear to be the fluorouracil-levamisole and fluorouracil-leucovorin regimens. The optimal schedule and dose of these agents remains to be determined. Portal vein chemotherapy infusion studies have yielded promising but inconclusive results to date. As data from completed or ongoing large group studies become available, the role of this modality will be better clarified. In rectal cancer, adjuvant radiotherapy alone has a modest but consistent ability to reduce local recurrence without demonstrating any survival advantage. The optimal dose and sequencing of radiotherapy remains poorly defined. Two completed cooperative group studies strongly suggest that the optimal use of radiotherapy is in combination with chemotherapy. The independent role of chemotherapy in rectal cancer remains unclear. There is suggestive evidence that adjuvant chemotherapy is more effective with rectal cancer than with primaries arising proximal to the peritoneal reflection. Despite the large number of unresolved questions that remain, the following interim treatment recommendations can be made: 1. Patients with Dukes' B and C rectal and colonic adenocarcinomas should be entered into an appropriate adjuvant clinical trial when feasible. 2. Outside the setting of a protocol, there is a sound rationale to treat Dukes' B and C rectal cancer with combination chemotherapy and postoperative radiotherapy. The chemotherapy could consist of fluorouracil either alone or combined with leucovorin. 3. In more proximal colonic tumors (above the pelvic peritoneal reflection), recently described improvements in survival for patients with Dukes' B disease suggests that adjuvant therapy should be withheld in this group when not participating in a clinical study. Patients with Dukes' C tumors should receive fluorouracil-levamisole.
Obstructive sleep apnea in children with Down syndrome. Children with Down syndrome have many predisposing factors for the obstructive sleep apnea syndrome (OSAS), yet the type and severity of OSAS in this population has not been characterized. Fifty-three subjects with Down syndrome (mean age 7.4 +/- 1.2 [SE] years; range 2 weeks to 51 years) were studied. Chest wall movement, heart rate, electroculogram, end-tidal PO2 and PCO2, transcutaneous PO2 and PCO2, and arterial oxygen saturation were measured during a daytime nap polysomnogram. Sixteen of these children also underwent overnight polysomnography. Nap polysomnograms were abnormal in 77% of children; 45% had obstructive sleep apnea (OSA), 4% had central apnea, and 6% had mixed apneas; 66% had hypoventilation (end-tidal PCO2 greater than 45 mm Hg) and 32% desaturation (arterial oxygen saturation less than 90%). Overnight studies were abnormal in 100% of children, with OSA in 63%, hypoventilation in 81%, and desaturation in 56%. Nap studies significantly underestimated the presence of abnormalities when compared to overnight polysomnograms. Seventeen (32%) of the children were referred for testing because OSAS was clinically suspected, but there was no clinical suspicion of OSAS in 36 (68%) children. Neither age, obesity, nor the presence of congenital heart disease affected the incidence of OSA, desaturation, or hypoventilation. Polysomnograms improved in all 8 children who underwent tonsillectomy and adenoidectomy, but they normalized in only 3. It is concluded that children with Down syndrome frequently in have OSAS, with OSA, hypoxemia, and hypoventilation. Obstructive sleep apnea syndrome is seen frequently in those children in whom it is not clinically suspected. It is speculated that OSAS may contribute to the unexplained pulmonary hypertension seen in children with Down syndrome.
Tuberous sclerosis with primary meningioma of the maxillary antrum. Primary extracranial meningiomas are uncommon; they have been documented in the ear, skin, orbit, parapharyngeal space, parotid gland, mediastinum, and rarely the paranasal sinuses. Tuberous sclerosis is an autosomal dominant neurocutaneous syndrome characterized by multiple connective tissue tumours. We report the first case of a tuberous sclerosis patient with a maxillary antral meningioma.