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Biomedical subjects

M Gross

Publications and source records attributed to M Gross.

At least 91 records · Page 5Linked to original sources
PubMed2001

European genomics: think big or small?

With the first draft of the human genome completed, Michael Gross looks at some of the plans to study a variety of European populations to exploit the new information.

Europe↗
PubMed2001

[Siblings with pediatric hearing loss. Data on age at diagnosis and degree of hearing loss].

The Deutsches Zentralregister für kindliche Hörstörungen (DZH = German Registry for Hearing Loss in Children) has so far (30.6.2000) entered data records of 4,027 permanently hearing impaired children. These records include data on a total of 151 pairs of siblings. In seven cases a third sibling was registered. An analysis of the data of siblings with different dates of birth shows that the diagnosis for older siblings was delayed 2 years on average compared to the younger siblings (mean 23.6 months, 95% confidence interval 19.3-27.8 months). The degree of hearing loss, which crucially determines the average age at which a child is diagnosed, correlates statistically significantly with pairs of siblings, so that misleading results can be almost totally avoided. In 11 of 17 cases of twins and triplets, the diagnosis was pronounced simultaneously for both siblings; in the remaining 6 cases, one sibling was diagnosed later. It has become apparent that younger siblings of hearing-impaired children profit from the concomitant routine diagnostic investigation of siblings of hearing-impaired children nowadays common in many institutions, but avoidable delays nevertheless still occur, as shown by the data for twins and triplets. Since in approximately 18% of the registered children with one or more siblings one of the brothers or sisters is likewise hearing-impaired, consistent family investigation is recommended.

Age Factors↗
PubMed2001

[Congenital hearing loss in children. 2: Genetic hearing loss].

Molecular genetic tests enable a differentiated view of patho-physiological correlation of sensori-neural hearing impairment. On the basis of 4791 records of the German Central Registry on Childhood Hearing Loss (Deutsches Zentralregister für kindliche Hörstörungen (DZH)) it was shown that 35% of all permanent hearing impairment in Germany is caused genetically and 20% are acquired. The proportion of indistinct etiology remains at 45%. The number of children who have a hearing impairment by birth is also vague. It has to be expected that approximately 5% of these children develop a hearing impairment afterwards albeit its genetic determination. In 4791 cases a syndromal phenotype was assumed in 8.9%. Practical advice is given for clinical routine diagnostics with pragmatic suggestions and some distinct syndromes are described. Hitherto identified deafness genes reveal their role in pathological auditory function. Future diagnostic and therapeutic strategies are outlined on the basis of molecular genetic methods.

Abnormalities, Multiple↗
PubMed2001

[Comparison of various parameters for determining an index of myocardial perfusion reserve in detecting coronary stenosis with cardiovascular magnetic resonance tomography].

For the assessment of myocardial perfusion with cardiac magnetic resonance imaging, different semiquantitative parameters of the first pass signal intensity time curves can be calculated and myocardial perfusion reserve indices can be determined. In this study we evaluated the feasibility of different perfusion parameters and their perfusion reserve indices for the detection of significant coronary artery stenosis. The signal intensity time curves of the first pass of a gadolinium-DTPA bolus injected via a central vein catheter before and after dipyridamole infusion were investigated in 15 patients with single vessel (stenosis > or = 75% area reduction) and five patients without significant coronary artery disease. For the distinction of ischemic and nonischemic myocardial segments, semiquantitative parameters, such as maximal signal intensity, contrast appearance time, time to maximal signal intensity and the steepness of the signal intensity curve's upslope determined by a linear fit, were assessed after correction for the input function. For each parameter a myocardial perfusion reserve index was calculated and cut off values for the detection of significant coronary stenosis were defined. The diagnostic accuracy of each parameter was then examined prospectively in 36 patients with coronary artery disease and compared with coronary angiography. Where as a distinction of ischemic and normal myocardium was possible with myocardial perfusion reserve indices, semiquantitative parameters at rest or after vasodilation alone did not allow such a distinction. The perfusion reserve index calculated from the upslope showed the most significant difference between ischemic and nonischemic myocardial segments (1.19 +/- 0.4 and 2.38 +/- 0.45, p < 0.001) followed by maximum signal intensity, time to maximum signal intensity and contrast apperance time. Sensitivity, specificity and diagnostic accuracy was 87, 82 and 85% for the detection of hypoperfusion induced by significant coronary artery stenoses using the perfusion reserve index calculated from the upslope. The steepness of the first pass signal intensity curve's upslope, determined by a linear fit, is a feasible parameter for the detection of significant coronary artery disease with MR. Based on a myocardial perfusion reserve index of this parameter, ischemic myocardium can be identified with high diagnostic accuracy.

Adult↗
PubMed2001

Regional variations in skin barrier function and cutaneous irritation due to iontophoresis in human subjects.

The effect of saline iontophoresis on skin barrier function and irritation was investigated on three body sites (abdomen, chest and upper arm) in order to select an appropriate site for iontophoretic delivery of drugs. Thirty healthy human volunteers were recruited according to specific entry criteria. Ten subjects, five males and five females, were assigned to each body site group. Skin barrier function and irritation was examined after 4 h of saline iontophoresis at a current density of 0.2 mA/cm(2) on a 6.5 cm(2) area in terms of the measured responses: transepidermal water loss (TEWL), skin capacitance, skin temperature and visual scores. Alterations in TEWL due to iontophoresis were not observed in the upper arm and chest; however, changes in TEWL at the abdomen were observed and returned to baseline 2 h after patch removal. Similarly, changes in capacitance due to iontophoresis returned to baseline (P>0.05) at the three body sites 2 h after patch removal except under the anode at the abdomen (P<0.05). There was a significant increase in skin temperature due to iontophoresis at the anode and the cathode (P<0.05) at the upper arm. Edema was not observed. At patch removal, the erythema score was significantly (P<0.001) elevated in comparison to baseline at the three body sites. Erythema resolved within 24 h except at the chest under the anode, where the erythema score was still higher (P<0.01) than the baseline. Papules appeared in five subjects at the active anode site on the chest. In three of the subjects, these papules did not resolve until 24 h post patch removal. Thus, there was regional variation in the function of the skin and irritation due to iontophoresis. Irritation was greater at the chest than at the abdomen or upper arm.

Abdomen↗
PubMed2001

Hemodilution - an overview of current canadian practices.

Background. Transplant teams evaluate potential organ and tissue donors to exclude donation of tissues at risk for disease transmission. Standards dictate that serological tests be performed on every donor to assess the presence of transmissible diseases including: Human Immunodeficiency Virus 1 & 2, Human T Lymphotropic Virus 1 & 2, Hepatitis C, Hepatitis B surface Antigen, Hepatitis B core Antibody and Syphilis. A limitation of serological testing is the risk of false negative results due to the dilution of the serum. Hemodilution results from the transfusion of fluids (blood products, colloids and/or crystalloid). Confidence in the accuracy and sensitivity of donor serology testing is of utmost importance to ensure the provision of safe organs and tissues for transplantation.Methods. In order to determine the preferred and validated methodology for determining hemodilution, if any; and to determine the level of hemodilution that jeopardizes serologic test results, we reviewed the literature and current testing practices. Tissue banks throughout Canada as well as accrediting bodies were contacted regarding the hemodilution algorithm they utilize.Results. In the absence of a pretransfusion sample, hemodilution calculations are the prevalent methodology for assessing sensitivity of serology testing. A literature search and personal communications provided no documentation on the validation of any hemodilution algorithm or evidence that 50% hemodilution is an acceptable level for accurate serology testing.Conclusion. A validation of hemodilution algorithms and the acceptable or unacceptable rate of hemodilution is required. The utilization of a validated algorithm should be mandated in standards to ensure continuity of practice by all transplantation centres. If validation cannot be obtained, alternative methodologies for serology testing should be investigated.

Journal Article↗
PubMed2001

[Manifestations of gastroesophageal reflux in the otorhinolaryngology tract].

BACKGROUND: Gastroesophageal reflux disease (GERD) is associated with a wide spectrum of otolaryngologic disorders and extraesophageal complications of the upper aerodigestive tract. Previous studies of patients diagnosed with GERD have reported symptoms such as asthma, chronic cough, pneumonia, laryngitis, but also other oral, rhinopharyngeal and laryngeal disorders, e.g. sore throat, globus sensation, and hoarseness. The objective of this study was to determine the incidence of gastroenterologic diseases in patients complaining of upper aerodigestive, pulmonary, laryngeal, pharyngeal, oral, and cervical disorders that are possibly attributable to GERD. PATIENTS: This study included 40 patients, who presented to the department of Otolaryngology with chronic complaints of at least one of the following symptoms or disorders during a minimum period of 3 months: dysphagia (n = 28), sensation of globus pharyngeus (n = 28), hoarseness (n = 20), odynophagia (n = 22), heartburn (n = 16), postnasal drip (n = 15), sore throat (n = 22), cough (n = 14), throat clearing (n = 11), laryngospasm (n = 6), and voice fatigue (n = 6). A complete examination of the head and neck was performed. Inflammatory disorders of the nose and the paranasal sinuses could not be confirmed by history, nasal endoscopy and Water's view x-ray or CT-scan of the paranasal sinuses in all patients. RESULTS: The main otorhinolaryngologic findings were laryngeal lesions (n = 38), including posterior laryngitis, erythema and edema of the interarytenoideal region, and chronic hyperplastic laryngitis. All patients were referred for gastroenterologic evaluation, where esophagogastroduodenoscopy was performed with histological examination of biopsy specimens. Different gastroenterologic diseases such as GERD, gastritis and hiatal hernia were confirmed in 30 of 40 cases, and appeared solely or in combination with each other. GERD was the most frequent gastroenterologic disease (48%), followed by hiatal hernia (45%) and Helicobacter pylori positive antrum gastritis (23%). Patients with GERD were treated with medical antireflux therapy, e.g. 20 mg to 40 mg of the proton pump inhibitor omeprazole daily. There was a remarkably good therapeutic outcome, since laryngeal disorders and findings as the result of gastroenterologic diseases resolved in 29 out of 30 patients. To date, these therapeutic results were maintained for the mean follow-up period of 8 months. CONCLUSIONS: It is concluded that in many patients, suffering from the above-mentioned otolaryngologic symptoms, occult gastroesophageal diseases are present. However, laryngoscopic findings are subtle and meticulous examination is mandatory. Medical antireflux treatment is effective for relief of symptoms and mucosal healing. Thus, extraesophageal otolaryngologic symptoms and laryngeal manifestations are to be considered as extragastrointestinal manifestations mainly of reflux disease.

Adult↗
PubMed2001

Meta-analysis: efficacy of therapeutic regimens in ongoing variceal bleeding.

BACKGROUND AND STUDY AIMS: Variceal bleeding is a major cause of mortality in liver cirrhosis. Therapeutic options include medical (vasoconstrictive/vasoactive drugs) and endoscopic (sclerotherapy/ligation) treatments. Most studies evaluating acute esophageal bleeding have included patients with both ongoing and recent bleeding. Therefore therapeutic efficacy in ongoing bleeding may not have been adequately determined in these studies. A meta-analysis was performed for two reasons: first to compare directly the various treatments in the case of ongoing bleeding, as this would not be accomplished by a single trial, and secondly, to determine the success rates of each treatment option based on a larger number of patients. METHODS: An extensive Medline search identified 13 randomized controlled trials with precise statements of the number of patients with ongoing bleeding and their clinical outcomes. All studies followed a similar design and a Q test excluded heterogeneity of the studies. Data were pooled and cumulative success rates were calculated. RESULTS: Ligation appeared to be the most effective treatment (91.0 %, 95 % CI 82.4-96.3 %); it was significantly more successful than vasoconstrictive treatment (vasopressin/terlipressin 68.7 %, 61.7-75.2 %; P < 0.002, chi-squared-test) or vasoactive treatment (somatostatin/octreotide, 75.9 %, 68.1-82.6 %; P < 0.02) treatment, but was not statistically better than sclerotherapy (81.1 %, 71.7-88.4 %). The latter therapy was not statistically superior to medical treatment options. Calculations of estimated true effects, which take into account the weight of each study, rendered similar results. CONCLUSION: Ligation is the most effective treatment option. No significant difference was found between the efficacy of sclerotherapy and treatment with somatostatin or octreotide.

Adult↗
PubMed2001

Stress levels for well-fitting implant superstructures as a function of tightening force levels, tightening sequence, and different operators.

STATEMENT OF PROBLEM: Unfavorable stress distribution and occlusal overload have been reported to result in failures ranging from screw loosening to loss of osseointegration. PURPOSE: The purpose of this study was to assess the effect of different tightening forces and sequences, with different operators, on stresses generated on an accurately fitting implant superstructure on multiple working casts made with a splinted impression technique. MATERIAL AND METHODS: The effects of different tightening forces (10 and 20 Ncm) were assessed with the use of 30 stone casts made from a metal master model with a splinted impression technique. Stresses generated were recorded by 4 strain gauges attached to the superior surface of the master framework. A multiple analysis of variance with repeated measures was performed to test for significant differences among the groups. RESULTS: Tightening force values at 10 Ncm ranged from 150.43 to 256 Ncm. At 20 Ncm, microstrain values ranged from 149.43 to 284.37 Ncm. Microstrain values related to the sequence of tightening ranged from 150.8 to 308.43 Ncm (left to right) and 154.63 to 274.80 Ncm (right to left). For the different operators, microstrain values ranged from 100.13 to 206.07 Ncm. No statistically significant differences among the variables of tightening force, tightening sequence, and operators were found ( P >.05). The interaction between groups and strain gauges was also found to be nonsignificant (P >.05). CONCLUSION: The potential of variable tightening force and tightening sequence to generate unfavorable preload stresses can be minimized through use of the splinted impression technique, which ensures an accurately fitting superstructure.

Analysis of Variance↗
PubMed2001

A "virtual hearing aid" for comparing hearing aids in children: a double-blind crossover study.

In this study, a "virtual hearing aid" was used to compare different types of hearing aids. A digital hearing aid (Oticon DigiFocus Compact) and an analogue, automatic reference hearing aid were compared in a group of 17 schoolchildren (median age: 10 years) with moderate to severe, symmetrical, sensorineural hearing loss. Differences in performance were assessed using routine diagnostic methods (speech recognition performance tests, loudness scaling), subjective assessments (questionnaires) and the "virtual hearing aid". Guaranteeing double-blind testing conditions, the "virtual hearing aid" offers the possibility to directly compare individual in-situ recordings of different hearing aids. In contrast to the clear subjective preferences for the digital hearing aid, we could not obtain any significant results with routine diagnostic methods. Using the "virtual hearing aid", the subjective comparison and speech recognition performance tasks yielded significant differences. The "virtual hearing aid" proved to be suitable for directly comparing different hearing aids under double-blind testing conditions.

Child↗
PubMed2001

Accuracy and safety of online clearance monitoring based on conductivity variation.

BACKGROUND: Haemodialysis dose has been shown to have a distinct impact upon the morbidity and mortality rate in patients on regular dialysis therapy. Accordingly, the adequacy of dialysis treatment should be guaranteed. METHODS: In 200 dialysis sessions two or three +/-10% dialysate conductivity variations were applied to test patient compliance and the accuracy of an electrolyte based online clearance measurement (OCM) reflecting the total clearance of urea. RESULTS: Using a step profile the electrolytic clearance showed highly significant correlation with the reference data in the blood side (n=118, r=0.867, P<0.001) and dialysate side (n=118, r=0.820, P<0.001) if only reference values were taken into account for which the error in mass balance did not exceed 5%. Kt/V according to the single pool model (n=35, r=0.940, P<0.001), the equilibrated single pool variable volume kinetic model (n=36, r=0.982, P<0.001), Daugirdas formula (n=34, r=0.951, P<0.001) and direct quantification of dialysance via spent dialysate (n=26, r=0.900, P<0.001) showed outstanding correlations with electrolyte-based Kt/V at mass balance error below 5%. No adverse clinical effect of OCM was reported. Serum sodium, body weight, heart rate and breathing rate at rest, arterial pO(2) and pCO(2) and blood pressure before haemodialysis remained unaffected in OCM measurements in comparison with baseline parameters. A small influx of sodium (1.53+/-7.62 mmol) into the patient was seen following the impulse, but no signs associated with fluid overload were observed during the study period of 10 consecutive dialysis sessions. CONCLUSIONS: The OCM option of the haemodialysis machine provides a safe and accurate tool for continuous online monitoring of total urea clearance.

Adult↗
PubMed2001

Dietary catechins in relation to coronary heart disease death among postmenopausal women.

Catechins, one of the major groups of flavonoids, are bioactive compounds present in a variety of plant foods and beverages. Experimental data suggest that they might prevent chronic diseases in humans. We studied whether the intake of catechins was inversely associated with the risk of coronary heart disease death in a prospective study of postmenopausal women from Iowa. Between 1986 and 1998, 767 of 34,492 participants initially free of cardiovascular diseases died from coronary heart disease. There was a strong inverse association between the intake of (+)-catechin and (-)-epicatechin and coronary heart disease death, which was somewhat attenuated after multivariate adjustment (risk ratios from lowest to highest quintile: 1.00, 0.95, 0.97, 0.77, 0.76). This inverse association was most pronounced in women at low risk of coronary heart disease (non-smokers, free of diabetes mellitus and cardiovascular diseases). A high intake of "gallates," catechins typical of tea, was not associated with coronary heart disease death. Of the major catechin sources, apples and wine were inversely associated with coronary heart disease death. Our data suggest that preventive effects might be limited to certain types of catechins, or that these are indicators of other dietary components or a healthy lifestyle in general.

Aged↗
PubMed2001

Slow diffusion of home HIV-specimen collection: provider concerns at odds with client preferences.

BACKGROUND: Home specimen collection and telephone counseling (HSCTC) may be a convenient new method for detection of HIV infection among cohorts at high-risk for HIV. GOAL: To evaluate attitudes about HSCTC among participants, HIV counselors, and community advisory board members associated with a national multisite study of persons at high risk for HIV. STUDY DESIGN: Twelve focus groups and surveys were conducted at six sites among 126 counselors, community advisory board members, and cohort participants. RESULTS: Staff and community advisory board members raised concerns about the acceptability, feasibility, safety, and effectiveness of HSCTC. In contrast, participants (92%) reported a willingness to collect blood and oral samples on a frequent basis, and preferred telephone (73%) to office-based counseling. CONCLUSION: Home specimen collection and telephone counseling appear to be preferred by study participants at high risk of HIV infection. Staff and community advisory board members had stronger reservations than prospective users.

Adolescent↗