shukoor65/lab-rag-model huggingface dataset:
Unilateral hydrocephalus: prenatal sonographic diagnosis. We studied six cases of unilateral hydrocephalus detected prenatally to analyze the sonographic features of the abnormality and to determine the cause and clinical outcome. In all cases, third-trimester sonograms showed marked unilateral lateral ventriculomegaly (mean atrial width, 4.4 cm) and normal contralateral lateral, third, and fourth ventricles. Five of the six cases had marked thinning of the cortical mantle on the affected side and shift of midline structures to the contralateral side. The causes of unilateral hydrocephalus were agenesis or stenosis of the foramen of Monro in three cases, transient obstruction of the foramen in one fetus with an intraventricular hematoma, underlying brain dysplasia in one fetus with a variant of holoprosencephaly, and undetermined in one case. All six neonates had placement of a ventriculoperitoneal shunt catheter; four of these have had normal cognitive development at follow-up. The remaining two infants have moderate to severe developmental impairment. Unilateral hydrocephalus is a rare anomaly that can be recognized by prenatal sonography. Even though unilateral ventriculomegaly may be marked, early diagnosis and treatment may result in a favorable clinical outcome.
An overview of ankle arthrodesis. Arthrodesis of the ankle can result in a painless, normal walking gait. However, complications in ankle arthrodesis can be major, and can occur when anatomy, deformity, or bony deficiency is not properly addressed. Nonoperative treatment should always be considered first, and, if possible, an open or arthroscopic ankle debridement can provide significant pain relief. Arthrodesis should be considered after conservative treatment fails. Infections, deformity, sensory deficiencies, and bony defects require special consideration. The use of bone graft and internal or external compression will enhance the likelihood of a successful arthrodesis.
Glandular odontogenic cyst: clinicopathologic analysis of three cases. The glandular odontogenic cyst is a rare cyst of odontogenic origin, first described in 1988 by Gardner et al. Three previously unreported glandular odontogenic cysts are presented; none recurred after the initial surgical treatment, and one example was associated with a squamous odontogenic tumor-like proliferation in the wall. Ten similar cases were found in the literature, and their clinical and roentgenographic features, and follow-up, have been compared with the present cases.
Progression of scleral disease. The clinical features of 290 patients with scleral inflammation were reviewed to determine whether a classification based on the anatomical site and clinical appearance of the disease at presentation reflected its natural history. The authors' results confirm that the majority of patients remain in the same clinical category throughout the course of their disease. Of the 104 (35.9%) patients who experienced a recurrence of their disease, only 12 had progressed from diffuse to nodular disease, and 10 patients who originally had nodular disease developed scleral necrosis. Patients with necrotizing scleritis were older than patients in the other groups and more frequently had an associated systemic disease than patients with either diffuse or nodular disease; necrotizing scleritis was the most difficult disease to treat. Diffuse anterior scleritis had a lower incidence of visual loss (9%) than either nodular scleritis (26%) or necrotizing disease (74%), and, therefore, the authors consider nodular scleritis a disease of intermediate severity between diffuse scleritis and necrotizing disease. In this series, 12% of patients presented with posterior scleritis, and visual loss was most frequent in this group (84%).
Antihypertensive drug treatment. Potential, expected, and observed effects on stroke and on coronary heart disease. The effects of prolonged differences in diastolic blood pressure (DBP) on the risks of stroke and of coronary heart disease (CHD) were estimated from nine major prospective observational studies involving about 420,000 men and women who were followed up for intervals of 6-25 years. The results indicate that a prolonged difference of about 6 mm Hg in DBP was associated with approximately 37% fewer strokes and 23% fewer CHD deaths and nonfatal myocardial infarctions. The effects of equivalent reductions in DBP produced by antihypertensive drug treatment but maintained for only a few years have been estimated in several overviews of randomized trials involving a total of 30,000-40,000 patients. The results of the overviews indicate that treatment reduced the risk of stroke by about 40%, suggesting that most or all the long-term potential benefits for stroke due to lower DBP were achieved within about 3 years of beginning treatment. The risks of nonfatal myocardial infarction and CHD death may have been reduced by about 10% among patients allocated to active treatment; the 95% confidence limits for the difference ranged from about zero to about 20%. Whatever the true effect of treatment on CHD, it would appear somewhat less than the difference in risk estimated from the observational studies for a prolonged difference in DBP of the same size. This apparent shortfall in benefit may reflect a long time-course for changes in DBP to have their full effects on CHD, possible adverse side effects of the principal trial treatments, or both.
Effect of ventilation with soluble and diffusible gases on the size of air emboli. Pulmonary hypertension resulting from venous air embolism is known to increase after ventilation with highly soluble and diffusible gases. Exacerbation of the hypertension could be due to further blockage of the circulation if the bubbles enlarge as a result of ingress of gas by diffusion. This mechanism has been frequently cited but lacks direct proof. To determine directly whether intravascular air bubbles actually enlarge when highly soluble and diffusible gases are inspired, we used microscopy to measure the size of gas emboli in vivo. When air bubbles were injected into the right atrium, the bubbles that appeared in pulmonary arterioles were larger during ventilation with helium or nitrous oxide than with air. Air bubbles injected into the pulmonary artery enlarged when the inspired gas was changed to helium or nitrous oxide. The direction, magnitude, and timing of changes in bubble size were consistent with a net diffusion of gas into the bubbles. These data support the idea that venous air emboli enlarge during ventilation with soluble and diffusible gases and thereby cause further vascular obstruction.
Platelet activation in the pathogenesis of unstable angina: importance in determining the response to plasminogen activators. Unstable angina is a clinical syndrome of recurrent myocardial ischemia. In some cases, this reflects episodic platelet activation and coronary thrombosis. Thus, the biosynthesis of thromboxane A2, which is largely derived from activated platelets, is increased, often coincident with chest pain. The major role of platelets in unstable angina may influence the response to plasminogen activators. Platelets increase the resistance of thrombi to lysis, by inducing clot retraction and cross-linking and by releasing inhibitors. Thus, coronary thrombi in unstable angina may be resistant to lysis. Furthermore, both t-PA and streptokinase cause platelet activation and thrombin formation in vivo, possibly via plasmin. Plasmin can activate platelets and factor V directly. These prothrombotic effects of plasminogen activators may limit their activity in unstable angina. At the very least, their therapeutic efficacy may be highly dependent on the coadministration of potent antiplatelet agents and anticoagulants.
Viral hepatitis. The new ABC's. Hepatitis may be caused by hepatitis A virus, hepatitis B virus, hepatitis C virus (classic non-A non-B viral hepatitis), hepatitis D virus (delta agent), and hepatitis E virus (epidemic non-A non-B viral hepatitis). Cytomegalovirus, Epstein-Barr virus, and herpes simplex virus may also occasionally cause hepatitis. Some forms of hepatitis carry the risks of chronic infection, cirrhosis, or hepatocellular carcinoma. Treatment options for viral hepatitis are limited and, in many cases, still under investigation. Prophylaxis is available for many forms of hepatitis and should be offered to those at risk.
Reversal of protein-bound vitamin B12 malabsorption with antibiotics in atrophic gastritis. The role of bacteria in the bioavailability of protein-bound vitamin B12 was examined in eight elderly subjects who had atrophic gastritis and in eight normal controls. On separate days and in random order, vitamin B12 absorption tests were performed using either radiolabeled crystalline or protein-bound vitamin B12. At the same time, bacterial samples were collected from the upper gastrointestinal tract. The tests and gastrointestinal aspirates were performed before and during tetracycline therapy. Crystalline vitamin B12 was absorbed to the same extent in the two study groups. Atrophic gastritis subjects absorbed significantly less protein-bound vitamin B12 than normal controls (mean +/- SEM, 0.7% +/- 0.2% vs. 1.9% +/- 0.5%, respectively). However, protein-bound vitamin B12 absorption in these subjects normalized after antibiotic therapy. These results suggest that the small amounts of vitamin B12 released from the protein binders is readily absorbed (as shown in vitro) and/or metabolized by bacteria.
Large vessel occlusion with vasculitis in systemic lupus erythematosus. Patients with SLE may have acute large vessel occlusion due to vasculitis and/or circulating antiphospholipid antibodies, as illustrated by the case we have reported. Unfortunately, delayed medical attention led to gangrene of the foot and amputation. Early recognition and appropriate treatment may significantly decrease morbidity and mortality. Medical treatment may include corticosteroids, thrombolysis, anticoagulation, or immunosuppression.
Angiotensin converting enzyme inhibitors. Present and future. The angiotensin converting enzyme (ACE)-inhibiting agents have emerged with the diuretic agents, beta-adrenergic receptor-blocking agents, and calcium antagonists as therapeutic options for major consideration during the initial treatment of hypertensive patients. These compounds antagonize a potent pressor mechanism underlying hypertensive disease. The ACE inhibitors curtail the generation of the potent octapeptide angiotensin II; in addition, degradation of the potent vasodilator bradykinin is inhibited. Hemodynamically, ACE inhibitors reduce arterial pressure through a decreased total peripheral resistance that is unassociated with reflex stimulation of the heart or expansion of intravascular volume. The arteriolar dilation accounting for the decreased vascular resistance seems to occur in each target organ of the disease. Unlike the direct-acting smooth muscle vasodilators or adrenergic inhibitors, ACE inhibitors dilate the efferent as well as the afferent glomerular arterioles and thereby reduce glomerular hydrostatic pressure and renal filtration fraction, even though renal blood flow and glomerular filtration rate are preserved. The ACE-inhibiting compounds not only reduce left ventricular afterload in hypertension but also diminish cardiac mass and wall thicknesses. The mechanism(s) for some of these actions have not yet been defined precisely, but they undoubtedly involve the autocrine/paracrine actions of the renopressor system and their effects in the cellular biologic events of vascular smooth muscle and the cardiac myocyte. It seems plausible and exciting that the "more local" renin-angiotensin systems will be exploited by those ACE inhibitors yet to be synthesized, which will result in new applications for this class of pharmacological agents.
Use of Valsalva maneuver to unmask left ventricular diastolic function abnormalities by Doppler echocardiography in patients with coronary artery disease or systemic hypertension. It has been suggested that changes in left atrial pressure may mask or mimic left ventricular diastolic function abnormalities detected by Doppler echocardiography. The effect of the Valsalva maneuver on the transmitral flow velocity profile was therefore studied in 28 patients without evidence of coronary artery disease (group 1, mean age +/- standard deviation 50 +/- 8 years) and in 94 patients with evidence of coronary artery disease or systemic hypertension (group 2, mean age 54 +/- 10 years). At baseline, group 2 patients had higher peak late diastolic filling velocity (A), lower peak early (E) to late diastolic filling velocity (E/A) ratio and longer isovolumic relaxation time than group 1, whereas heart rate, E velocity and E deceleration time were similar in both groups. During Valsalva, both groups had similar increases in heart rate and similar decreases in E velocity but E/A ratio decreased significantly only in group 2 because of a lesser decrease in A velocity. The E/A ratio was greater than or equal to 1.0 both before and during Valsalva in all but 1 patient in group 1, whereas in group 2, 32 patients had E/A greater than or equal to 1.0 at rest and during Valsalva, 33 patients had E/A greater than or equal to 1.0 at rest but less than 1.0 both at rest and during Valsalva. Using group 1 as controls, prevalence, specificity and positive predictive value of E/A less than 1.0 in group 2 were 31, 100 and 100% at rest and 66, 96 and 98% during Valsalva.
Membrane cerebral lipids in Rett syndrome. The lipid membrane composition of cerebral tissue from 5 patients with classic Rett syndrome, ages 12-30 years, and from 14 age-matched controls was studied. The results demonstrated a selective loss of myelin-associated lipids and an enrichment of gangliosides in temporal white matter. The ganglioside pattern revealed an increase of astroglial cell-associated gangliosides and reduced proportions of gangliosides GD1a and GT1b. This latter finding may be crucial in synaptic function. The fatty acid compositions of ethanolamine phosphoglyceride, choline phosphoglyceride, and galactosylceramide were normal.
Effect of respiratory muscle fatigue on subsequent exercise performance. The purpose of this study was to determine whether induction of inspiratory muscle fatigue might impair subsequent exercise performance. Ten healthy subjects cycled to volitional exhaustion at 90% of their maximal capacity. Oxygen consumption, breathing pattern, and a visual analogue scale for respiratory effort were measured. Exercise was performed on three separate occasions, once immediately after induction of fatigue, whereas the other two episodes served as controls. Fatigue was achieved by having the subjects breathe against an inspiratory threshold load while generating 80% of their predetermined maximal mouth pressure until they could no longer reach the target pressure. After induction of fatigue, exercise time was reduced compared with control, 238 +/- 69 vs. 311 +/- 96 (SD) s (P less than 0.001). During the last minute of exercise, oxygen consumption and heart rate were lower after induction of fatigue than during control, 2,234 +/- 472 vs. 2,533 +/- 548 ml/min (P less than 0.002) and 167 +/- 15 vs. 177 +/- 12 beats/min (P less than 0.002). At exercise isotime, minutes ventilation and the visual analogue scale for respiratory effort were larger after induction of fatigue than during control. In addition, at exercise isotime, relative tachypnea was observed after induction of fatigue. We conclude that induction of inspiratory muscle fatigue can impair subsequent performance of high-intensity exercise and alter the pattern of breathing during such exercise.
Effect of temporary occlusion of hypogastric arteries on blood loss during radical retropubic prostatectomy. We report on a prospective, partially randomized study of 130 patients, examining the effect of temporary occlusion of the hypogastric arteries on intraoperative blood loss, perioperative blood replacement and change in preoperative to postoperative hematocrit. We observed no significant difference in any of these parameters when comparing patients who did and did not undergo intraoperative occlusion of the hypogastric arteries. These findings suggest that temporary occlusion of the hypogastric arteries during radical prostatectomy does not have a major effect on the blood loss associated with this operation. Extensive collateral circulation to the prostate and a substantial venous component of blood loss may explain these findings. Banking of 3 units of autologous blood preoperatively would have decreased the need for homologous transfusions in the majority of patients.
Cross-resistance patterns in ACNU-resistant glioma sublines in culture. Three ACNU-resistant clones (R1, R3, and R12) were isolated from 9L rat glioma cells under selection pressure of ACNU in vitro. The authors have investigated the mechanisms of resistance and characteristics of these clones at the cellular level by studying cross-resistance patterns to chemical and physical agents. Although these resistant sublines showed complete cross-resistance to methyl-chloroethylnitrosourea (MCNU), no cross-resistance was observed for other alkylating agents, while each of the resistant sublines showed partial cross-resistance to structurally dissimilar toxic agents (vinblastine, Adriamycin, and VP-16). No difference in ACNU uptake was observed between 9L and R3 cells, and resistance patterns among alkylating agents suggested that the mechanism of ACNU resistance was specific to bifunctional nitrosoureas. Based on a transport study, this multidrug resistance could be explained by reduced intracellular uptake of these drugs, but there seemed little possibility that membrane P-glycoprotein, which usually is observed in typical multidrug-resistant cells, was expressed in these ACNU-resistant cells because enhanced drug efflux was not found in ACNU-resistant sublines. Significant collateral sensitivity to L-asparaginase indicated that ACNU might disturb the asparagine synthetic pathways by its mutagenic action. The increased level of total glutathione in the resistant sublines may be one mechanism of radiation or ACNU resistance.
Cervicofacial cystic hygroma. Patterns of recurrence and management of the difficult case. Cystic hygromas usually present in infancy or early childhood as compressible masses that may rapidly and intermittently enlarge. While they may arise in any anatomic location, hygromas of the head and neck are especially difficult to manage since enlargement may cause serious sequela such as airway obstruction, feeding difficulties, and speech pathology. Complete extirpation of these lesions is often impossible, and recurrence rates are accordingly high. We reviewed our 10-year experience in treating cervicofacial cystic hygromas. Of 34 patients, 21 had lesions cephalad to the hyoid and 13 had lesions caudal to the hyoid. While none of the 13 children with infrahyoid lesions demonstrated feeding or respiratory difficulties, eight of 21 children with suprahyoid involvement presented with dysphagia or airway compromise. The recurrence rates for infrahyoid and suprahyoid lesions were 15% and 81%, respectively. Those children with suprahyoid hygromas also experienced an increased operative complication rate compared with patients with infrahyoid involvement. Principles of management for suprahyoid and infrahyoid lesions are described, including the specific management of lingual, submandibular, parotid, and parotofacial hygromas.
Can essential hypertension be subclassified with respect to mechanism? Hypertension may result from a variety of abnormalities. The rise in blood pressure may trigger other secondary events that further influence cardiovascular homeostasis. The ability to measure some markers associated with hypertension or the responsiveness of blood pressure to nutritional interventions or to specific therapeutic agents may also have pathogenetic implications. The ultimate goal of further knowledge in this area should be to understand the fundamental abnormalities responsible for hypertension. Such insight would permit more effective treatment and, perhaps, primary prevention of this ubiquitous and multifaceted disorder.
Effectiveness of imazodan for treatment of chronic congestive heart failure. The Imazodan Research Group. A 12-week, multicenter, double-blind, randomized, placebo-controlled trial of imazodan, a type III phosphodiesterase inhibitor, was conducted in 147 patients with congestive heart failure to determine clinical efficacy and safety. Patients were randomized to placebo or 2, 5 or 10 mg of imazodan administered twice daily. Patients were maintained on their standard therapy including diuretics, digoxin and an angiotensin-converting enzyme inhibitor. The mean ejection fraction was 23 +/- 10%. Exercise time increased from baseline in all 4 groups. There was no significant difference observed between the placebo group and any of the treated groups with regard to exercise time, ejection fraction, frequency of ventricular premature complexes or ventricular tachycardia. When analyzed by intent to treat, the placebo mortality was 7% (3 of 44) and the imazodan mortality was 8% (8 of 103) (p = not significant). This study failed to demonstrate that imazodan provided any benefit in exercise performance when compared with placebo.
The anal continence plug: a disposable device for patients with anorectal incontinence. Anorectal incontinence is most commonly found in the elderly, but colorectal surgeons now see an increasing number of younger patients with this condition. Although medical and surgical treatments are available, a proportion of patients remain refractory to therapy. We investigated the efficacy of three designs of anal continence plug. 8 women and 2 men (mean age, 52 years) who were incontinent to both liquid and solid stool tested each plug for three consecutive weeks. 1 patients withdrew from the study. The median weartime for the optimum plug design was 12 h, and there were no episodes of incontinence in 82% of the periods during which the plug was in place. Patients required a median of eleven plugs per week, and in 82% of cases insertion was as easy as with a suppository. Plugs may have a place in the management of patients with anorectal incontinence.