123rc/medical_text huggingface dataset:
Overview: renal physiology and pathophysiology of aging. Cross-sectional studies in humans have suggested that there is a progressive decline of renal function with age after 40 years. The decline in various functions (eg, tubular maximums, concentrating and diluting abilities, and acidification) tend to parallel the decreases in glomerular filtration rate (GFR) and renal blood (plasma) flow (RPF). Recent observations from the Baltimore Longitudinal Study of Aging suggest that not all individuals follow this pattern, and that, indeed, many show no decline and some even an increase in their renal function over time. Whether the observed decreases in renal function with aging are the results of intervening pathologic processes, eg, immunologic, infectious, and toxic injury and ischemia, or can be related to hyperperfusion and hyperfiltration with resultant glomerulosclerosis, or to some other relentless involutional process, remains unclear. The purpose of this report is to review the descriptive studies documenting the changes in renal morphology and physiology with age and to discuss what is known about mechanisms involved in these losses of renal substance and function.
Periprosthetic chronic inflammation characterized through the measurement of superoxide anion production by synovial-derived macrophages. Periprosthetic macrophages were isolated from the synovium of primary and revision arthroplasty patients. Inflammatory activity was determined by the level of superoxide (O2-) production de novo and in response to phorbol myristate acetate (PMA) stimulation. Nonstimulated primary arthroplasty-derived macrophages produced 2.54 +/- 2.04 pmoles of O2-/minute/10(5) cells. When identical reaction tubes were stimulated with PMA, O2- levels increased to 5.76 +/- 3.77 pmol of O2-/minute/10(5) cells. Nonstimulated revision arthroplasty-derived macrophages produced 3.26 +/- 2.02 pmol of O2-/minute/10(5) cells during this ten-minute time period. When identical reaction tubes were stimulated with PMA, O2- levels increased to 3.98 +/- 2.52 pmol of O2-/minute/10(5) cells. The difference in the ratio of O2- production in response to stimulation between primary and revision groups was statistically significant. The observation of a chronic moderate level of activation and the lack of responsiveness to a potent stimulator suggests that macrophage inflammatory activity is down-regulated in periprosthetic synovium.
Hemodynamic efficacy of rapid saline infusion and dobutamine versus saline infusion alone in a model of cardiac rupture. Despite recent reports describing survival after cardiac rupture, the effectiveness of circulatory support while awaiting definitive surgical treatment is controversial. To assess the efficacy of volume expansion and pharmacologic support in cardiac tamponade due to cardiac rupture, a model of hemorrhagic cardiac tamponade was developed and treatment with rapid saline infusion and dobutamine was compared with rapid saline infusion alone in 15 closed chest dogs. A right ventricular wound of reproducible size was produced by deflating an aortic valvuloplasty balloon that had previously been passed by way of the internal jugular vein into the pericardial space and through a stab wound in the right ventricular free wall. Hemodynamic values were compared at baseline, during tamponade and after a rapid infusion (1 liter at 100 ml/min) of either saline solution alone or saline solution plus dobutamine (20 micrograms/kg per min). Atrial and pericardial pressures increased significantly in both groups. Mean arterial pressure, cardiac output and stroke volume increased with combined saline and dobutamine infusion to values similar to those at baseline (91 +/- 19%, 114 +/- 43% and 94 +/- 37% of baseline, respectively). In contrast, saline infusion alone caused a small increase in cardiac output but failed to significantly increase mean arterial pressure or stroke volume (76.8 +/- 14.2%, 55 +/- 18% and 51 +/- 17% of baseline, respectively). Combined rapid infusion of saline solution and dobutamine infusion has a more beneficial hemodynamic effect and may be more effective than rapid saline infusion alone in resuscitating patients with hemorrhagic cardiac tamponade due to cardiac rupture.
Effect of obesity on safe duration of apnea in anesthetized humans. Obese patients have a decreased functional residual capacity and, hence, a reduced oxygen supply during periods of apnea. To determine whether obese patients are at greater risk of developing hypoxemia during induction of anesthesia than patients of normal weight, 24 patients undergoing elective surgical procedures were studied. Group 1 (normal) were within 20% of their ideal body weight. Group 2 (obese) were more than 20% but less than 45.5 kg over ideal body weight. Group 3 (morbidly obese) were more than 45.5 kg over ideal body weight. Patients were preoxygenated for 5 min or until expired nitrogen was less than 5%. After induction of anesthesia and muscle relaxation the patients were allowed to remain apneic until arterial saturation as measured by pulse oximetry reached 90%. The time taken for oxygen saturation to decrease to 90% was 364 +/- 24 s in group 1, 247 +/- 21 s in group 2, and 163 +/- 15 s in group 3; these times are significantly different at P less than 0.05 between groups. Regression analysis of the data demonstrated a significant negative linear correlation (r = -0.83) between time to desaturation and increasing obesity. These results show that obese patients are at an increased risk of developing hypoxemia when apneic.
Malignant adenolymphoma of the parotid gland: report of carcinomatous transformation. Malignant transformation of an adenolymphoma (Warthin's tumour) is a rare event. This paper presents a case of carcinoma arising in an adenolymphoma of the parotid gland.
High dietary fiber and low saturated fat intake among oligomenorrheic undergraduates. Numerous functional risk factors are associated with the occurrence of secondary amenorrhea in young women. Less is known regarding factors associated with the more prevalent problem of oligomenorrhea. We have evaluated nutrient intake, body composition, perceived psychological stress, 24-hour urinary cortisol, and urinary C peptide (UCP) in 35 eumenorrheic, 11 mildly oligomenorrheic, and 10 oligomenorrheic nonathletic undergraduate women. Nutrient intake was evaluated by a validated food frequency questionnaire. Oligomenorrheic women were found to consume significantly more dietary fiber, crude fiber, and polyunsaturated fat, and significantly less saturated fat than their eumenorrheic classmates. Oligomenorrheic women had significantly lower 24-hour UCP excretion than mildly oligomenorrheic women. The groups did not differ in any aspect of body composition, body weight, age of menarche, perceived psychological stress, or urinary cortisol excretion. The data suggest that higher intake of fiber and lower intake of saturated fat may be associated with oligomenorrhea among otherwise healthy undergraduate nonathletic women.
Rapid admixture blood warming: technical advances. The technique of rapid admixture blood warming of cold erythrocyte units is designed to warm erythrocyte units rapidly (less than 30 sec) while simultaneously providing saline for dilution. However, questions have been raised about the recommended use of a standard 250-ml bolus of 70 degrees C admixture saline, the uniformity and speed of blood unit warming, the difficulties inherent in keeping saline bags at 70 degrees C, and the safety of the methodology. To answer these questions, a series of tests were performed and modifications of the technique were introduced. The mean weight of 1000 successive units of erythrocytes for adult infusion was 305 g (range 220 to 410). The maximum temperature was 44 degrees C, using an internal temperature probe (1-cm temperature gradations; 2-sec recording intervals) when the smallest unit was admixed with a 250 ml 70 degrees C saline bolus; the largest unit had a minimum temperature of 30 degrees C. Plasma Hgb, osmotic fragility, and K of the minimum size erythrocyte unit showed no significant deviation from its control. Both thermographic photographs and the internal temperature recordings of the erythrocyte units demonstrated that solely due to fluid turbulence, uniform mixing occurs within approximately 30 sec of beginning the admixture process. Inverting the blood units caused a thermal layering of fluids and an unacceptable maximum blood temperature of 50 degrees C. There was no difference between the mixing time or efficacy in the presence of standard or large-bore iv tubing or additional in-line filters. Volumes of the 250-ml saline bags for admixture decreased markedly with deviations in electrolyte composition after greater than 2 wk at 70 degrees C.
Syringomatous squamous tumors of the breast. Four cases are reported of syringomatous squamous tumors of the breast occurring in women aged 37 to 70 years. The lesions were characterized histologically by relatively well-circumscribed tumor-like nodules composed of a proliferation of teardrop or comma-shaped islands of squamous epithelium. The squamous epithelial islands contained central lumens lined by eosinophilic cuticles and were surrounded by a densely cellular fibrous matrix, thus closely resembling the growth pattern of dermal eccrine syringomas. The lesions appeared to arise de novo from breast parenchyma without evidence of transitions with the surrounding normal or hyperplastic mammary epithelium and were not associated with the overlying skin or nipple epidermis. In all cases, the surrounding breast tissue showed fibrocystic and benign proliferative changes, and in one case, the lesion was found in the vicinity of a large cyst surrounded by microcalcifications. All patients were treated by local surgical excision and have shown no evidence of recurrence over a follow-up period of 1 to 6 years. The histologic differential diagnosis and the possible pathogenesis of these lesions are discussed.
Alarm reaction and serum K+ in hypertensive patients. The effect of serum K+ of the alarm reaction induced by the participation to an experimental noninvasive study was evaluated in 35 subjects with borderline hypertension and in 18 essential hypertensives. A group of 44 inpatients undergoing routine blood sampling served as a control. Serum K+, blood pressure and heart rate were measured before (casual) and after (baseline) 20 min of rest in the recumbent position. Baseline serum K+ values were significantly higher than casual values in patients participating to the experimental protocol while no change was observed in inpatients undergoing routine blood sampling. The increase in serum K+ induced by relaxation was significantly related to heart rate decrease (r = 0.73). After relaxation 75% of patients had an increase in serum K+ with a change greater than 10% in about 35% of patients. In a subgroup of patients who repeated the same test three times, the alarm reaction was still evident and not reproducible within each patient. These data suggest that when potassium levels are measured in outpatients undergoing diagnostic or experimental procedures falsely reduced levels can be found in a large proportion of subjects.
Protective and curative effects of rifampicin in Acanthamoeba meningitis of the mouse. BALB/c mice inoculated nasally with Acanthamoeba culbertsoni, resulting in amebic encephalitis and death 3-7 days, were treated with rifampicin prophylactically (daily for 2 days with 75 and 100 mg/kg) and after infection (daily for 5 days with doses of 10-100 mg/kg). Prophylactic treatment resulted in full protection against infection, as assessed by absence of symptoms of central nervous system malfunction and negative brain culture 10 days after inoculation. Curative treatment was effective at the same doses; however, at doses of 10, 25, and 50 mg/kg, only two of six animals were free of symptoms and infection.
Familial trigeminal anesthesia. Familial congenital trigeminal anesthesia as an isolated abnormality is an unusual disorder. To our knowledge, only one family has previously been reported. We report here a family with three affected members demonstrating facial anesthesia, bilateral corneal changes, and nasal septal damage secondary to self-traumatization. Magnetic resonance imaging demonstrated hypoplasia of gasserian ganglia and trigeminal nerves in the affected father of two affected sons. The pathogenesis of this disorder appears to be congenital hypoplasia of the trigeminal nerves and gasserian ganglia that is inherited in a dominant fashion.
The neglected medical history and therapeutic choices for abdominal pain. A nationwide study of 799 physicians and nurses. A random national sample of 501 physicians and 298 nurse practitioners was presented a case vignette describing a patient with epigastric pain and endoscopy showing diffuse gastritis. Respondents were encouraged to request further information and then were asked for recommendations. History available if requested included substantial use of aspirin, coffee, cigarettes, and alcohol, and severe psychosocial stress. More than one third of the physicians chose to initiate therapy without seeking a relevant history. Nearly half of all physicians indicated that a prescription would be the single most effective therapy; 65% recommended a histamine antagonist. By contrast, only 19% of nurse practitioners opted to treat without taking further history; the nurse sample asked an average of 2.6 questions vs 1.6 for physicians; only 20% of the nurses recommended a prescription medication. These findings raise concerns about the adequacy of basic history taking in this setting and the underuse of nonpharmacologic approaches in favor of excessive reliance on prescription drugs, even when not indicated by clinical circumstances.
Deficiency of calcitonin gene-related peptide in Raynaud's phenomenon. Skin biopsy samples from the fingers of nine patients with primary Raynaud's phenomenon, nine with the disorder associated with systemic sclerosis, and eleven healthy controls were examined by immunocytochemistry. There were no differences between the groups in the distribution of PGP 9.5 (a pan-neuronal marker) immunoreactivity, but there was a significant reduction in the number of calcitonin gene-related peptide (CGRP) immunoreactive neurons in the skin of patients with primary Raynaud's phenomenon and those with systemic sclerosis. These findings implicate dysfunction of the CGRP neurovascular axis in the pathophysiology of Raynaud's phenomenon.
Oral contraceptives and breast cancer. Review and meta-analysis. To evaluate the relation between use of oral contraceptives and the incidence of breast cancer, the authors reviewed the epidemiologic literature and used quantitative methods to summarize the data. Study results for any use of oral contraceptives were pooled using a model that accounted for both interstudy and intrastudy variability. The authors also explored interstudy variability and modeled a duration-effect relation between oral contraceptive use and breast cancer. Case-control and follow-up studies were considered separately. Overall, the authors observed no increase in the risk of breast cancer for women who had ever used oral contraceptives, even after a long duration of use. These results were consistent across study design. However, data combined from case-control studies revealed a statistically significant positive trend (P = 0.001) in the risk of premenopausal breast cancer for women exposed to oral contraceptives for longer duration. This risk was predominant among women who used oral contraceptives for at least 4 years before their first term pregnancy (relative risk = 1.72; 95% confidence interval = 1.36 to 2.19). Additional study is required to determine whether this finding in a subgroup of exposed women is confirmed and whether the risk remains increased with advancing age.
Immunopathology of diabetes in the RT6-depleted diabetes-resistant BB/Wor rat. Insulin-dependent diabetes mellitus appears to be an autoimmune disease that is characterized morphologically by insulitis, an inflammation of the pancreatic islets of Langerhans that results in the destruction of the insulin-producing beta cells. The RT6-depleted DR rat provides a good model for the in situ study of insulitis. The authors used the anti-RT6.1 monoclonal antibody to selectively deplete RT6 T cells in DR rats and produce a synchronous and rapid development of insulitis that commences 10 days after treatment. The phenotype of cells that infiltrated the islets at different stages of insulitis in the RT6-depleted DR rat was determined by immunocytochemical techniques. A prodromal period of 10 days was present in which the authors could not detect morphologic alterations within the pancreas. This is followed by a second phase of early insulitis in which a few islets are infiltrated by macrophages and T cells. This rapidly progresses by 18 days to the final phase of generalized insulitis in which the islets are massively infiltrated by macrophages and T cells.
Stationary vs. mapping manometry in evaluating dysphagia. Two methods are used to assess esophageal motility. The mapping technique uses catheter withdrawal at 1 cm steps until the entire esophagus is evaluated. A simpler method is commonly used that involves keeping the catheter stationary for the entire evaluation. We compared these 2 techniques in 30 patients referred for the evaluation of dysphagia. Emphasis was placed on the distal 10 cm of the esophagus because this is the primary location of esophageal motility disorders. There was excellent correlation between techniques for mean distal amplitude (r = 0.945), mean distal duration (r = 0.942), and percentage of non-peristaltic contractions (r = 0.967). The overall manometry diagnosis was similar by both methods in 27 (90%) patients. Three patients had different manometry diagnoses resulting from use of the two techniques. However, the change in diagnosis was only clinically important in one patient in whom the mapping technique identified a segmental motility disorder that had been missed by the stationary technique. Stationary manometry had a 94% sensitivity and 93% specificity rate for identifying motility disorders compared to mapping manometry. We conclude that stationary manometry is a simple and accurate method for evaluating esophageal pressures and distal disorders. Only those patients with normal results of stationary studies may benefit by further mapping to identify rare segmental motility disorders.
Concurrent and construct validity of the Pediatric Evaluation of Disability Inventory. The purpose of this study was to determine the validity of the Development Edition (pilot version) of the Pediatric Evaluation of Disability Inventory (PEDI) in groups of disabled and nondisabled children. The PEDI is a new functional assessment instrument for the evaluation of disabled children aged 6 months to 7 years. The PEDI has been developed to identify functional status and change along three dimensions: 1) functional skill level, 2) caregiver assistance, and 3) modifications or adaptive equipment used. The PEDIs were administered as a parental-report questionnaire, and the results were compared with data obtained by the Battelle Developmental Inventory Screening Test (BDIST). The BDIST is a standardized assessment with developmental and adaptive content. Subjects were 20 children between the ages of 2 and 8 years with arthritic conditions and spina bifida and 20 nondisabled children matched for age and sex. All subjects' scores on the BDIST cognitive domain were no greater than 1.50 standard deviations below the mean for their age group. Concurrent validity was supported by moderately high Pearson product-moment correlations between BDIST and PEDI summary scores (r = .70-.80). Construct validity was supported by significant differences between the disabled and nondisabled groups' PEDI scores and by discriminant analysis identifying the PEDI scores as better group discriminators than the BDIST scores. Results validate the Developmental Edition of the PEDI and support the further development and standardization of the final version. Use of the PEDI in clinical pediatric physical therapy practice is discussed.
Neurobehavioral effects of phenytoin prophylaxis of posttraumatic seizures In order to determine potential negative neurobehavioral effects of phenytoin given to prevent the development of posttraumatic seizures, 244 subjects were randomized to phenytoin or placebo. They received neurobehavioral assessments at 1 and 12 months postinjury while receiving their assigned drug and at 24 months while receiving no drugs. In the severely injured, phenytoin significantly impaired performance at 1 month. No significant differences were found as a function of phenytoin in the moderately injured patients at 1 month or in either severity group at 1 year. Patients who stopped receiving phenytoin according to protocol between 1 and 2 years improved more than corresponding placebo cases on several measures. We conclude that phenytoin has negative cognitive effects. This, combined with lack of evidence for its effectiveness in preventing posttraumatic seizures beyond the first week, raises questions regarding its use for long-term prophylaxis. Our findings do not negate phenytoin's proven efficacy in controlling established seizures nor do they indicate that its cognitive effects are worse than other anticonvulsant drugs.
Polymorphisms of GLUT2 and GLUT4 genes. Use in evaluation of genetic susceptibility to NIDDM in blacks. The liver/islet (GLUT2) and muscle/adipose tissue (GLUT4) glucose-transporter gene products, membrane proteins that facilitate glucose uptake into cells, are important molecules for normal carbohydrate metabolism. Recent isolation of the genes encoding these proteins provides a means to assess the role of possible defects that might contribute to impaired glucose-stimulated insulin secretion or impaired insulin-mediated glucose uptake, both prominent phenotypic features of non-insulin-dependent diabetes (NIDDM). A GLUT2 cDNA clone was isolated from a human liver cDNA library to search for polymorphisms at this locus in American Blacks. Three highly polymorphic sites were identified, one of which (EcoRI-Hae III) appears to be due to an insertion and/or deletion of 200 base pairs of DNA. Significant linkage disequilibrium between these sites over approximately 30 kilobases of genomic DNA suggested that these polymorphisms could be in linkage disequilibrium with mutations at this locus if they exist. A GLUT4 cDNA clone was also utilized to search for polymorphisms at this locus, but only one previously described polymorphism was observed. GLUT2 and GLUT4 cDNA probes were used to evaluate DNA polymorphisms in genomic DNA from American Blacks with NIDDM. The allelic, genotypic, and haplotypic frequencies of the DNA polymorphisms at these loci did not differ from the frequencies in nondiabetic subjects. Because no associations with NIDDM were found, it appears unlikely that mutations at these loci contribute in a major way to the genetic susceptibility to NIDDM observed in American Blacks.