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Biomedical subjects

W Mueller

Publications and source records attributed to W Mueller.

At least 37 records · Page 2Linked to original sources
PubMed1998

Method for analysis of exhaled air by microwave energy desorption coupled with gas chromatography-flame ionization detection-mass spectrometry.

A method for chemical analysis of volatile constituents in exhaled air of mechanically ventilated patients is described. Exhaled substances are adsorbed and concentrated onto activated charcoal, desorbed by microwave energy and transferred into a gas chromatograph for separation without prior cryofocusing. Substances are identified by flame ionisation detection and mass spectrometry. This method yields reproducible results and is well suited for clinical studies.

Acetylene↗
PubMed1997

Effects of dietary fat restriction on particle size of plasma lipoproteins in postmenopausal women.

Hypertriglyceridemia is an independent risk factor for coronary artery disease (CAD) and is also commonly associated with other coronary risk factors, ie, small, dense low-density lipoprotein (LDL) particles and low plasma levels of high-density lipoprotein cholesterol (HDL-C). Dietary fat restriction is recommended for the prevention of nutrition-related cancers. Low-fat, high-carbohydrate intake can increase plasma triglyceride (TG) and decrease HDL-C. In general, plasma TG levels are inversely related to the particle size of LDL. We investigated the effects of dietary fat restriction on the concentration and particle size of plasma lipoproteins in 14 healthy postmenopausal women (aged 61 +/- 11 years). During a 4-month period of eucaloric controlled feeding, dietary fat was reduced stepwise from a habitual intake of 33% +/- 8% to 23% and then to 14% of daily energy. Changes in the plasma lipid level and particle size of very-low-density lipoprotein (VLDL), LDL, and HDL were determined at the end of each dietary phase. Increasing carbohydrate intake without weight loss was associated with an increase in plasma TG (1.86 +/- 0.30 v 2.47 +/- 0.37 mmol/L) and decreases in total cholesterol (5.82 +/- 0.25 v 5.40 +/- 0.21 mmol/L), LDL-C (3.07 +/- 0.18 v 2.61 +/- 0.21 mmol/L), HDL-C (1.42 +/- 0.1 v 1.24 +/- 0.1 mmol/L), and apolipoprotein (apo) A1 (5.14 +/- 0.25 v 4.61 +/- 0.36 mmol/L), whereas plasma apo B did not change. The particle size of VLDL increased (42.7 +/- 1.4 v 47.0 +/- 0.9 nm). However, there was no change in either LDL (25.1 +/- 0.2 v 25.3 +/- 0.2 nm) or HDL particle size. Although at each level of dietary fat intake LDL particle size correlated inversely with plasma TG and apo B, there was no relationship between the increase in plasma TG and LDL particle size. These results show that hypertriglyceridemia caused by a eucaloric high-carbohydrate intake is not associated with a decrease in LDL particle size. Therefore, carbohydrate-induced hypertriglyceridemia may not have the same atherogenic potential as genetic hypertriglyceridemias.

Aged↗
PubMed1997

Blood pressure reactivity in urban youth during angry and normal talking.

Distinctions between male and female adult patterns of cardiovascular disease are well established. Although risk for cardiovascular disease begins early in life, little research has been focused on the beginning of gender difference patterns. This pilot study examined blood pressure reactivity, gender, and biologic maturity in adolescents talking about angry life circumstances and the usual progression of their day. Systolic and diastolic blood pressure increased during talking, and the addition of biologic maturity to the analysis distinguished males from females. Males had higher systolic blood pressures than did females throughout the protocol, and, generally, mature subjects had higher systolic and diastolic blood pressures than did less mature subjects. These pilot data confirm the effects of talking on blood pressure. The data suggest that biologic maturity enhances understanding of gender differences in adolescent blood pressure reactivity and continued study of the gender-blood pressure reactivity distinctions in adolescents may further understanding of adult patterns of gender differences in cardiovascular disease.

Adolescent↗
PubMed1997

MR imaging of lumbar spondylolysis: the importance of ancillary observations.

OBJECTIVE: The purpose of this study was to determine the frequency of characteristic ancillary MR findings in patients with lumbar spondylolysis. MATERIALS AND METHODS: The radiology reports and clinical records of 64 patients (16 female, 48 male; 12-77 years old) with 66 levels of lumbar spondylolysis who had undergone MR imaging were retrospectively reviewed. Spondylolysis was established by conventional radiography in all 64 patients and by CT in 18 patients. The proportion of patients with spondylolysis in whom sagittal MR images showed ancillary findings of an increased sagittal diameter of the spinal canal, reactive marrow changes in the pedicle, or abnormal wedging of the posterior aspect of the vertebral body was retrospectively determined. This proportion was then compared with the proportion of patients in whom spondylolysis was correctly diagnosed by the initial interpreters of the MR images, who used only direct visualization of defects of the pars interarticularis to make the diagnosis. RESULTS: Twenty (30%) of 66 levels of lumbar spondylolysis were misdiagnosed when the MR images were initially interpreted using direct visualization of defects of the pars interarticularis. An increased sagittal diameter of the spinal canal was the most common ancillary observation, occurring at 60 of 66 levels of lumbar spondylolysis. This finding was present in all patients with grade II, III, or IV spondylolisthesis, in 95% of patients with grade I spondylolisthesis; and in 77% of patients with no anterolisthesis. Thirty-two (48%) of 66 lumbar levels showed wedging of the posterior aspect of the vertebral body, which correlated significantly with the grade of spondylolisthesis. Reactive marrow changes in the pedicle distinct from normal adjacent levels were seen on MR images in 24(36%) of 66 levels of lumbar spondylolysis. On MR images, 97% of all levels of lumbar spondylolysis yielded one or more ancillary observations, including all 20 of the cases originally misdiagnosed. CONCLUSION: The combined use of ancillary observations and direct visualization of pars interarticularis defects makes MR imaging effective in revealing lumbar spondylolysis.

Adolescent↗
PubMed1997

Role of laparoscopic surgery in pediatric urology.

OBJECTIVES: In our clinic, laparoscopy was introduced in 1987 for the exploration of non-palpable testes and since 1991 it has also been applied with therapeutic aims. We present our experience with this minimally invasive technique in pediatric patients. PATIENTS AND METHODS: Between May 1987 and September 1996, 219 laparoscopic procedures were performed in children. All children received general anesthesia. Positioning of the patient on a rotatable and tiltable operating table is very important. RESULTS: All laparoscopic interventions were well tolerated in children. The operative time for exploration of a nonpalpable testis ranged from 10 to 30 min, and for varix ligation from 15 to 30 min. In nephrectomy and nephroureterectomy cases 80-150 min were required. The excision of the urachal remnant and the drainage of lymphocele took between 30 and 70 min. No immediate postoperative complications were observed. Mobilization and oral intake were routinely carried out on the day of surgery. The children required little or no postoperative pain medication. CONCLUSION: Laparoscopy has been found to be the most reliable diagnostic tool in evaluating nonpalpable testes within the pediatric population. This approach enables subsequent therapy of laparoscopic orchiectomy, primary laparoendoscopic orchidopexy, or laparoscopically assisted two-stage Fowler-Stephens maneuver. Laparoscopic varix ligation is a simple and highly effective treatment modality for the pubescent male with a symptomatic varicocele. To date, the recurrence rate is 1.8% based on 80 patients followed for over 1 year. Fenestration of lymphoceles following renal transplantation has been found to be as efficaciously treated with laparoscopy as with open surgery. Laparoscopic nephrectomy and/or nephroureterectomy are technically demanding procedures and should only be performed by an experienced laparoscopic surgical team to minimize the complication rate. At the present time, the intraoperative costs of laparoscopic surgery are greater than with open surgery due to the use of disposable instrumentation and longer operating room times. However, minimally invasive surgery continues to gain a greater and more important role in the field of pediatric urology.

Adolescent↗
PubMed1997

Accuracy of single-voxel proton MR spectroscopy in distinguishing neoplastic from nonneoplastic brain lesions.

PURPOSE: To measure the accuracy of single-voxel, image-guided proton MR spectroscopy in distinguishing normal from abnormal brain tissue and neoplastic from nonneoplastic brain disease. METHODS: MR spectroscopy was performed at 0.5 T with the point-resolved spectroscopic pulse sequence and conventional postprocessing techniques. Subjects consisted of a consecutive series of patients with suspected brain neoplasms or recurrent neoplasia and 10 healthy adult volunteers. Fifty-five lesions in 53 patients with subsequently verified final diagnoses were included. Spectra were interpreted qualitatively by visual inspection by nonblinded readers (prospectively) with the benefit of prior clinical data and imaging studies, and by blinded readers (retrospectively). The nonblinded readers interpreted the spectra as diagnostic or not, and, if diagnostic, as neoplastic or nonneoplastic. The blinded readers classified the spectra as diagnostic or not, and, if diagnostic, as normal or abnormal and as neoplastic or nonneoplastic (when abnormal). The sensitivity, specificity, positive and negative predictive values, and accuracy were calculated from blinded and nonblinded MR spectroscopy interpretations. A receiver operator characteristic (ROC) curve analysis was performed on blinded MR spectroscopy interpretations. RESULTS: The diagnostic accuracy averaged across four blinded readers in differentiating patients from control subjects was .96, while the area under the aggregate (pooled interpretations) ROC curve approached unity. Accuracy in the nonblinded and blinded discrimination of neoplastic from nonneoplastic disease was .96 and .83, respectively. The area under the aggregate ROC curve in the blinded discrimination of neoplasm from nonneoplasm was .89. CONCLUSIONS: Image-guided proton spectra obtained at 0.5 T from patients with suspected neoplasia can be distinguished from spectra in healthy control subjects, and neoplastic spectra can be distinguished from nonneoplastic spectra with a high degree of diagnostic accuracy.

Adult↗
PubMed1996

Prognostic value of E-cadherin expression in 413 gastric carcinomas.

E-cadherin is a Ca(2+)-dependent intercellular adhesion molecule known to exert an invasion-suppressor function. In the present study, E-cadherin expression was immunohistochemically investigated in a retrospective series of 413 RO-resected gastric carcinomas using the monoclonal antibody (MAb) 5H9. Of these cases, 108 tumors revealed a preserved E-cadherin expression similar to that of normal gastric mucosa. In 95 tumors, E-cadherin expression was moderately reduced and in 86 tumors highly reduced. In 124 tumors, no or only a very weak dotted expression could be detected. There was a significant correlation between the degree of E-cadherin expression and the grade of tumor differentiation, as well as with histological type according to the Laurén and the WHO classifications. In contrast, no correlation could be demonstrated between E-cadherin expression and the prognostic parameters depth of invasion, lymph node involvement and vascular invasion. As shown by univariate Cox regression analysis, patients with E-cadherin-positive tumors had significantly better 3-and 5-year survival rates than patients with E-cadherin-negative tumors. This prognostic impact remained present in a multivariate Cox regression analysis, including the prognostic parameters pT category, pN category and vascular invasion.

Adult↗
PubMed1996

A new side effect of inhaled nitric oxide in neonates and infants with pulmonary hypertension: functional impairment of the neutrophil respiratory burst.

INTRODUCTION: Inhaled nitric oxide (NO) may be beneficial in the treatment of pulmonary hypertension, both of the newborn and in the adult respiratory distress syndrome. Up to now, serious systemic side effects have not been reported. OBJECTIVE: The effect of inhaled NO on superoxide anion production by neutrophils. DESIGN: Prospective study of a consecutive series of 15 neonates and infants. SETTING: Neonatal and paediatric ICUs with a total of 17 beds (university hospital). MEASUREMENTS AND RESULTS: Superoxide anion production was determined by a flow cytometric method using dihydrorhodamine 123 (DHR) as an oxidative probe after the priming of neutrophils with N-formyl-methionyl- leucylphenylalanine (fMLP) or with Escherichia coli. The generated fluorescence was expressed as relative fluorescence intensity (RFI). Inhalation of NO for more than 24 h reduced the superoxide anion production by neutrophils stimulated with E. coli to below baseline values before NO inhalation (mRFI = 158 +/- 25 vs 222 +/- 24; P = 0.03). This decrease was more pronounced after more than 72 h (mRFI = 133 +/- 17). At this time, superoxide anion production by fMLP-stimulated neutrophils was also decreased (mRFI = 40 +/- 3, vs 57 +/- 5; P = 0.03). The reduced capacity of superoxide production persisted throughout therapy with NO and lasted up to more than 4 days after the end of NO inhalation. CONCLUSION: The results suggest that inhalation of NO in patients with pulmonary hypertension causes reduced superoxide anion production by neutrophils stimulated with E. coli or with fMLP. To determine the clinical importance of this systemic side effect with respect to bacterial infections, a randomized controlled study is necessary.

Administration, Inhalation↗
PubMed1996

Relationship of plasma leptin to plasma insulin and adiposity in normal weight and overweight women: effects of dietary fat content and sustained weight loss.

Leptin, the product of the human homologue of the ob gene, which is defective in the obese (ob/ob) mouse, may be a humoral regulator of human adiposity. Plasma leptin concentrations were measured by RIA in 19 normal weight [body mass index (BMI) = 24.5 +/- 0.6 kg/m2] and 19 overweight to obese (BMI = 34.7 +/- 1.2 kg/m2) nondiabetic postmenopausal women on sequential controlled weight-maintaining diets containing 31%, 23%, and 14% of energy as fat, each for 4-6 weeks. Thereafter, the subjects ate a very low fat diet (< 15%) ad libitum; plasma leptin and insulin concentrations, BMI, percent body fat (%BF), and resting energy expenditure were determined after 6 and 8 months. Absolute and adiposity-corrected plasma leptin levels were higher in overweight/obese women (37.7 +/- 3.5 ng/mL; 1.01 +/- 0.07 ng.mL-1.%BF-1) than in normal weight women (16.9 +/- 2.2 ng/mL; 0.57 +/- 0.06 ng.mL-1.%BF-1, both P < 0.005 vs. obese), but were not different between the 31%, 23%, and 14% fat diets when body weight was stable. Plasma leptin was highly correlated with BMI (r = 0.81, P < 0.0001), %BF (r = 0.80, P < 0.0001), and fasting plasma insulin (r = 0.61, P < 0.0001). After 8 months on the ad libitum low fat diet, the women had lost an average of 6.9 +/- 1.0% of body mass (-2.0 +/- 0.3 kg/m2, P < 0.0001). In 15 subjects who lost more than 7% of body mass (-12.3 +/- 1.0%), plasma leptin concentrations decreased (-9.6 +/- 1.9 ng/mL, P < 0.0005), and the decrease of plasma leptin per change of adiposity (delta leptin/delta %BF) was greater in overweight/obese women (3.6 +/- 0.5) than in normal weight women (0.9 +/- 0.4, P < 0.01 vs. obese). In 18 other subjects who lost less than 7% of body mass (-2.7 +/- 0.6%), plasma leptin was unchanged (+1.4 +/- 1.4 ng/mL). Overall, the change of plasma leptin was significantly correlated with change of BMI (r = 0.43, P < 0.02), the change of %BF (r = 0.49, P < 0.005), the change of resting energy expenditure (r = 0.40, P < 0.02), and with the change of plasma insulin independently of changes of body adiposity (r = 0.45, P < 0.01). We conclude that plasma leptin concentrations are: 1) not affected by dietary fat content per se; 2) highly correlated with BMI, %BF, and plasma insulin in both overweight/obese and normal weight women; 3) decreased in parallel with plasma insulin after sustained weight loss; and 4) decreased more in overweight/obese than in normal weight women.

Adipose Tissue↗
PubMed1995

Infected arteriovenous hemodialysis graft presenting as left and right infective endocarditis.

Prosthetic grafts have become an acceptable alternative to the autogenous arteriovenous dialysis fistula. The major drawback in their use for the dialysis patient is infection. We present a case of infected polytetrafluoroethylene arteriovenous fistula (endarteritis) with signs of unilateral splinter hemorrhage, Janeway lesions in the affected limb and septic venous embolization to the lungs. The graft eventually ruptured requiring emergency surgery. Staphylococcus aureus is by far the most common implicated organism. An otherwise non-threatening infection at a fistula site can lead to more serious complications such as infective endocarditis.

Blood Vessel Prosthesis↗
PubMed1993

Group A rotaviruses produce extrahepatic biliary obstruction in orally inoculated newborn mice.

Extrahepatic biliary atresia is a devastating disease occurring in 1 in 10,000 to 14,000 infants annually in the United States. We have recently described preliminary data suggesting an association of group C rotavirus with biliary atresia in two infants. However, a group C rotavirus animal model of biliary atresia is not presently available. On the other hand, some strains of the better-characterized and much more common group A rotaviruses produce hepatobiliary disease in infant mice. This disease shares many characteristics of the human infection. The present report describes extrahepatic biliary obstruction in immunocompetent BALB/c infant mice infected with a human or animal strain of group A rotavirus. Two-d-old BALB/c mice orally inoculated with hepatobiliary tropic rotavirus were shown to have active virus replication in the biliary tract and liver as early as 48 h postinoculation. At approximately 7 d postinoculation, between one fourth and one half of infant mice, depending on the virus strain, showed signs of inflammation and swelling in the bile ducts. The obstruction was complete in about one half of symptomatic animals. Although there was no obvious atresia as described in human infants, the obstruction was irreversible about 50% of the time, and the resulting fibrosis and bile ductular proliferation in the liver were strikingly similar to those seen in the liver of the human infant with biliary atresia.

Administration, Oral↗
PubMed1993

Safety and effectiveness of intranasal administration of sedative medications (ketamine, midazolam, or sufentanil) for urgent brief pediatric dental procedures.

Thirty children presenting to the dental clinic of a pediatric hospital who required brief but urgent dental care, and who could not be satisfactorily examined or treated, were administered one of three medications--ketamine (Ketalar), 3 mg/kg; midazolam (Versed), 0.4 mg/kg; or sufentanil (Sufenta), 1.5 or 1.0 micrograms/kg--intranasally in a randomized, double-blinded protocol. The patients were brought to the day surgery area following appropriate fasting and administered one of the medications diluted in a dose of 0.1 mL/kg normal saline while sitting in a nurse's arms. Cardiorespiratory monitors were applied when tolerated, and the child was placed on the operating room table. Each child was injected locally with up to one dental cartridge of 2% lidocaine with 1:100,000 epinephrine before dental extractions. A sedation score was recorded using a scale where 1 = hysterical/untreatable, 5 = ideal sedation, and 10 = obtunded and desaturated, requiring airway management assistance. Midazolam administration resulted in acceptable sedation (mean score: 4) with no desaturations below 90% as measured by pulse oximetry and a mean recovery room observation time of only 3 +/- 2 min (+/- SD). Ketamine also had a mean sedation score of 4 and a short recovery period (7 +/- 7 min); however, two children experienced brief desaturations. Sufentanil at 1.5 micrograms/kg was noted to produce much more heavily sedated children (mean score 7), with a high incidence of significant oximetry desaturation (80%) and prolonged recovery room duration (58 +/- 40 min). Use of 1.0 microgram/kg sufentanil resulted in no desaturations, less sedation (mean score 4), and a brief recovery time (7 +/- 13 min).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed1993

The advantages of laparoscopic assisted bipolar high-frequency surgery.

Monopolar and bipolar application techniques of high-frequency surgery are compared concerning safety regulations, functional and energetic aspects and aspects of application. The availability of newly developed bipolar and multipolar surgical instruments for cutting and coagulating without instrument change and at low high-frequency power opens up a new dimension in laparoscopic assisted electrosurgery. The well-known risks of using monopolar instruments in laparoscopy have been eliminated with the new instrumentation presented.

Electric Conductivity↗
PubMed1990

Microheterogeneity of acute phase proteins in the differentiation of polymyalgia rheumatica from polymyositis.

We studied an alpha-1-acid glycoprotein (AGP) and an alpha-1-antichymotrypsin (ACHT) microheterogeneity in sera of patients with polymyalgia rheumatica (PMR), giant cell arteritis (GCA/PMR), polymyositis/dermatomyositis (PM/DM) and healthy individuals by affinity electrophoresis with concanavalin A (Con-A) as the ligand. Our results are expressed as reactivity coefficients. The mean of AGP reactivity coefficients (AG-RC +/- SD) in PMR (0.92 +/- 0.17) and GCA/PMR (0.91 +/- 0.12) were significantly lower compared with the mean AG-RC in patients with PM/DM (1.48 +/- 0.52) as well as in healthy individuals (1.34 +/- 0.9). Moreover, an additional microheterogeneous form of AGP was noted in patients with PM/DM. In parallel, we also found that the mean of ACHT reactivity coefficients (AC-RC +/- SD) were lower in patients with PMR (2.94 +/- 1.24) and GCA/PMR (1.66 +/- 0.16) compared with healthy individuals (3.92 +/- 1.17). The mean of AC-RC in patients with PM/DM (6.74 +/- 4.35) was significantly higher than in patients with PMR and GCA/PMR as well as in healthy individuals. Our results show that the changes in reactivity of AGP and ACHT with Con-A are useful diagnostic markers for the differentiation of PMR and GCA/PMR from PM/DM.

Acute-Phase Proteins↗
PubMed1989

Health effects during a smog episode in West Germany in 1985.

In January 1985 a smog period occurred for 5 days in parts of West Germany, including the Rhur District. Mortality (24,000 death certificates), morbidity in hospitals (13,000 hospital admissions, 5400 outpatients, 1500 ambulance transports) and consultations in doctors' offices (1,250,000 contacts) were studied for a 6-week period including the smog episode and a time interval before and thereafter. The study region was the State of North Rhine-Westfalia (16 million inhabitants), but the analysis is restricted to the comparison of the polluted area and a control area (6 million inhabitants each). During the smog period, mortality and morbidity in hospitals increased in the polluted area, but there was no substantial increase in the control area. The increases were for the total number of deaths 8 vs. 2% (polluted area vs. control area), for hospital admissions 15 vs. 3%, for outpatients 12 vs. 5% and for deliveries by ambulance to hospitals 28% in the polluted area (not investigated in the control area). The effects were more pronounced for cardiovascular diseases than for respiratory diseases. The consultations in doctors' offices show a slight decrease (-2 vs. -4%). Regression analysis shows a moderate influence of temperature, but a strong influence of ambient air pollution. The maxima of the ambient concentrations are more important on the same day, whereas the influence of the daily averages is more pronounced after a delay of 2 days. The results are discussed considering other possible confounders such as indoor pollution and psychogenic influences of the alarm situation. In total, the study suggests moderate health effects due to increased air pollution during the smog episode.

Acid Rain↗