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Biomedical subjects

P Lang

Publications and source records attributed to P Lang.

At least 289 records · Page 16Linked to original sources
PubMed1990

The postoperative spine. Magnetic resonance imaging.

MRI is rapidly becoming the imaging modality of choice in the diagnostic assessment of patients with persistent or recurrent symptoms following spinal surgery. It displays the normal postoperative findings as well as most causes of FBSS. MRI can differentiate persistent or recurrent disk herniation from postoperative scar formation with a greater degree of confidence than other imaging modalities. MRI can determine clinically important functional instability when CT and conventional radiography are inconclusive. This can be particularly helpful in evaluating the patient with multiple lumbar surgeries. MRI can also determine the presence of other causes of the FBSS such as lateral spinal stenosis, arachnoiditis, fat graft compression on the thecal sac, and presence of postoperative hematoma or postoperative infection.

Adipose Tissue↗
PubMed1989

Oral health knowledge and attitudes of elementary schoolteachers in Michigan.

Teachers at elementary schools in two areas (urban and rural) of Michigan were surveyed to determine their sources of information about oral health and their knowledge and attitudes about dental diseases and disease prevention. Questionnaires were completed by 404 teachers (62% response rate). More than 80 percent of respondents from both areas were female. Demographic characteristics that were significantly different between groups included: median ages of urban and rural respondents (P less than .01), median numbers of years in teaching (P less than .01), and median years in residence (P less than .03). Despite these differences, responses to the questionnaire varied little. For both groups, the most frequently cited sources of information about dental health were dentist's office (82%), followed by magazines and books (74%). The teachers considered preventing tooth decay as the most important reason for good oral hygiene. When asked to rank the effectiveness of ten methods of preventing caries in children, teachers ranked efficacious methods such as fluoridated water and pit and fissure sealants lower than making regular dental visits and reducing intake of sugared foods. Asked to rank the most effective method for children to receive fluoride, urban respondents ranked fluoridated water first, while rural respondents ranked this measure third. Findings suggest that teachers' knowledge about oral health and current methods of prevention is incomplete, is inaccurate in some instances, and varies little by geographic area.

Adult↗
PubMed1989

Results of the arterial switch operation for transposition of the great arteries with ventricular septal defect. Surgical considerations and midterm follow-up data.

Between January 1983 and December 1987, 62 patients underwent an arterial switch operation for transposition of the great arteries with ventricular septal defect or double outlet right or left ventricle. There were three hospital deaths (4.8%), and no deaths occurred in neonates (less than 1 month of age, n = 18). There were three late deaths, one due to coronary obstruction and two due to pulmonary vascular obstructive disease. One child has been lost to follow-up. We have prospectively evaluated the remaining 55 survivors by clinical evaluation, echocardiography, cardiac catheterization, ambulatory electrocardiographic monitoring, and limited electrophysiologic studies. The mean length of follow-up has been 27 +/- 16 months since surgery. One child has required reoperation for a residual ventricular septal defect; no child has undergone reoperation for supravalvar pulmonary or aortic stenosis. Aortic regurgitation was identified in 12 children (22%), which was mild in 11 and moderate in one. One child has asymptomatic occlusion of the left main coronary artery, one child has a tiny right coronary artery-to-pulmonary artery fistula, and one child has abnormal left ventricular wall motion according to follow-up angiography. No other abnormalities of systemic (left) ventricular function have been identified at late follow-up. In addition to the two late deaths due to pulmonary vascular obstructive disease, three children, all of whom were repaired at more than 6 months of age, have elevated pulmonary vascular resistance. Notable postoperative arrhythmias include complete heart block in four patients and nonsustained supraventricular or ventricular tachycardia early after surgery in eight patients (all resolved without medication at later follow-up). Only two patients have evidence of sinus node dysfunction and have not required treatment. The low hospital mortality and encouraging early follow-up data represent a significant improvement over atrial level repairs, supporting the arterial switch operation as the procedure of choice for children who have transposition of the great arteries with ventricular septal defect or double outlet ventricle. Because of the potential for the development of early pulmonary vascular obstructive disease in these patients, repair is recommended within the first 2 months of life.

Coronary Vessels↗
PubMed1989

Interferon-gamma upregulates the susceptibility of human neuroblastoma cells to interleukin-2-activated natural killer cells.

The influence of interferon-gamma on the susceptibility of neuroblastoma cells in cell-mediated killing was investigated. Neuroblastoma cells were only weakly susceptible targets for peripheral mononuclear cells. However, enrichment of natural killer (NK) cells or activation of NK cells with interleukin-2 resulted in a considerable increase of neuroblastoma cell lysis. Pretreatment of neuroblastoma targets with interferon-gamma additionally increased the susceptibility to enriched NK cells as well as to interleukin-2-activated NK cells. The conjugate formation between enriched NK cells and the neuroblastoma targets was not affected by the pretreatment of the targets with interferon-gamma. Concomitantly, treatment of the neuroblastoma targets with interferon-gamma resulted in a strong induction of otherwise poorly expressed major histocompatibility complex (MHC) class I antigen expression. These results suggest that the increased expression of MHC class I antigens on target cells is not always correlated with decreased sensitivity for NK cells but can also be followed by an increased susceptibility for NK cells.

Antigens, Neoplasm↗
PubMed1989

[Significance of IGA antigliadin antibodies during primary glomerulonephritis with mesangial IGA deposits].

The association of IgA anti-gliadin antibodies and IgA glomerulonephritis (IgA GN) was first reported in 1987 (Am J Nephrol, 1987, 7, 178-183) and has since been confirmed by other groups. We have developed a second generation ELISA (alkaline phosphatase, biotin-avidin) and used it to test 45 adult IgA GN, 34 idiopathic membranous nephropathy (MN), 31 idiopathic nephrotic syndrome (INS), and 11 idiopathic membranoproliferative glomerulonephritis (MPG) patients. IgA anti-gliadin antibodies were found in 24 IgA GN (53%), 1 MN (3%), 1 INS (3%), and 1 MGP (9%) patients. The presence of these antibodies in a patient with proteinuria strongly suggests IgA GN, with a sensitivity of 53%, a specificity of 96%, a positive predictive value of 88% and a negative predictive value of 77%. The presence of IgA anti-gliadin antibodies in IgA GN did not necessarily indicate coeliac disease because: a) neither IgG nor IgA anti-reticulin nor IgA anti-endomysium antibodies were found; b) intestinal absorption tests (folates, EDTA) were normal; c) biopsies of the small intestine were normal; and d) a gluten-free diet did not alter the evolution of the disease. Immunochemical analysis (footprinting after separation of the gliadins by rocket electrophoresis) showed the variability of the fractions recognized by the IgA antibodies from patients and controls, in addition to the absence of a typical profile. Gliadin does not have a lectin effect, since mannan and mannose did not inhibit the ELISA. Immunofluorescent labeling of human kidney with purified rabbit IgG anti-gliadin antibodies did not reveal a common epitope shared by gliadin and renal structures.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme-Linked Immunosorbent Assay↗
PubMed1989

Serum IgG subclasses and IgM imbalances in adult IgA mesangial glomerulonephritis and idiopathic Henoch-Schoenlein purpura.

Serum IgG subclass levels were investigated in 27 IgA GN and HSP patients and 19 healthy paired controls using a panel of monoclonal antibodies. IgG1 and IgG2 were statistically lower than in the controls in both the non-nephrotic and nephrotic patients, and 80% of the non-nephrotic patients exhibited a partial deficiency for either IgG1, IgG2 or IgG3. Urinary losses of IgG only accounted for decreased levels of IgG4. Fifty-four percent of these patients exhibited decreased IgM levels. This IgG-IgM imbalance may increase the susceptibility of these patients to viral and bacterial infections of the upper respiratory tract and trigger the renal disease. These findings raise the hypothesis that this IgG-IgM imbalance might be involved in the etiopathogenesis of these diseases.

Adolescent↗
PubMed1989

Magnetic resonance imaging of the ischemic femoral head in pigs. Dependency of signal intensities and relaxation times on elapsed time.

The magnetic resonance (MR) signal behavior of freshly excised pig femoral heads undergoing ischemic necrosis in vitro was evaluated. Ten femoral heads removed from skeletally immature pigs were stored at 37 degrees in a sealed, sterile container during the observation period. Imaging was initially performed 40 minutes after excision (base-line) and repeated at six, 12, 24, 48, and 72 hours. Changes in MR signal intensity were measured, and the T1 and T2 relaxation times were calculated for selected epiphyseal and metaphyseal areas. Signal intensities decreased during the first 24 hours and returned to baseline by 72 hours. T1 relaxation time increased most significantly between baseline and 24 hours and then decreased to near baseline level between 48 and 72 hours. T2 changes over time were not statistically significant. The type of localized, distinctive decreases in MR signal intensity occurring in clinical cases of early nontraumatic femoral head osteonecrosis was not observed in pigs. Such changes appear to require the presence of an intact and vigorous repair response within adjacent viable bone. However, the transient decrease in signal intensity and prolongation of T1 relaxation time at 12, 24, and 48 hours after traumatic vascular insult may be indicators of early femoral head ischemia.

Animals↗
PubMed1988

Heart-rate spectral analysis: a noninvasive probe of cardiovascular regulation in critically ill children with heart disease.

Children may die suddenly and unexpectedly following cardiac surgery, even while receiving intensive medical care, when current noninvasive and invasive monitoring techniques fail to warn us of an impending problem. This report examines the efficacy of heart-rate spectral analysis, a noninvasive method that quantitates the beat-to-beat fluctuations in heart rate, in characterizing and tracking cardiovascular regulatory status. A total of 45 heart-rate fluctuation studies, performed on selected patients, at the bedside, using heart-rate spectral analysis, were retrospectively correlated with clinical events. The spectral pattern of 18 patients who sustained a cardiac arrest differed significantly from the others in the study group (p less than 0.0001).

Adolescent↗
PubMed1988

[Magnetic resonance tomography in spondylolysis and spondylolisthesis].

40 patients with spondylolisthesis and/or spondylolysis were studied by magnetic resonance imaging (MR), 12 of whom with correlation to CT. CT proved to be more sensitive in detecting pars defects than MR. Sagittal MR, however, was more accurate in assessing spondylolisthesis than axial CT. At present, CT is superior to MR in demonstrating bony abnormalities. MR appears indicated in the patient undergoing spinal fusion in whom detection of intervertebral disc degeneration in the levels above or below intended fusion may lead to extension of fusion to the degenerated levels. Lack of ionizing radiation makes MR an ideal diagnostic method in evaluating spondylolisthesis in children and adolescents.

Adult↗