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Biomedical subjects

M Gross

Publications and source records attributed to M Gross.

At least 55 records · Page 3Linked to original sources
PubMed2002

[The value of magnetic resonance cholangiography for the expedient diagnosis of choledocholithiasis].

INTRODUCTION: Management of symptomatic cholecystolithiasis is vitally influenced by dilated biliary tract and choledocholithiasis. The objectives of this prospective pilot study were to evaluate the diagnostic value of preoperative magnetic resonance cholangiography (MRC) compared to diagnostic endoscopic retrograde cholangiography (ERC) and to establish an efficient algorithm for diagnostics and treatment of choledocholithiasis. METHODS: All consecutive patients with cholecystolithiasis and dilated biliary tract proven by sonography as well as elevated liver function tests were enrolled within 12 months. Patients without evidence of bile duct calculi underwent preoperative MRC, whereas patients with choledocholithiasis immediate ERC. RESULTS: 58 patients (30 male, 28 female) with a median age of 59.4 years underwent preoperative MRC. In 18 patients (10 male, 8 female; median age 63.5 years) with evidence of choledocholithiasis we subsequently performed ERC and papillotomy. Bile duct stones were detected and removed after papillotomy in 10 patients, whereas calculi could not be found anymore in 8 patients. The remaining 40 patients without calculi evident on MRC were transferred to magnetic resonance tomography and ERC in case of suspected malignancy or to cholecystectomy and intraoperative cholangiography (IOC), which could definitely exclude choledocholithiasis. In comparison to ERC respectively IOC, MRC was able to detect bile duct stones with a sensitivity of 100% and a specificity of 83.3%. CONCLUSIONS: Non-invasive MRC seems to replace diagnostic ERC concerning the presence of choledocholithiasis in case of cholecystolithiasis and dilated biliary tract with a high sensitivity. The preoperative ERC with stone extraction is still the therapy of choice in case of radiologically confirmed choledocholithiasis.

Aged↗
PubMed2002

Improved procedure of colonoscopy under accompanying music therapy.

BACKGROUND: Administration of sedatives and analgetics during colonoscopy includes the risk for arterial hypotension and respiratory depression. The aim of this study was to assess whether music therapy increases patients tolerance and reduces the need of analgo-sedative premedication. METHODS: 146 consecutive patients were examined in a randomized, prospective study. Colonoscopy was performed under intravenous administration with titrated dosages of midazolam and pethidin. Oxygen was given in cases of blood desaturation below values of 90%. Patients younger than 18 and older than 80 years, patients with history of partial colectomy, gastrectomy or hysterectomy and patients with colonic tumorous or inflammatory stenosis were excluded. 60 patients underwent conventional procedure (Group A), whereas 59 patients received additional music therapy (Group B). Time required to reach the cecum (examination time) was measured and the rate of successful colonoscopies was determined. RESULTS: Most of the patients required sedation with midazolam in both groups (97 vs. 93%), whereas more group A patients required analgesia with pethidin than group B patients (43 vs. 31%, p<0.05). Under music therapy the rate of completed colonoscopies was higher (group A 93%, group B 98%) and examination time was significantly accelerated (group A 22.8 +/- 14.6 min, group B 16.8 +/- 11.8 min, p<0.03). CONCLUSIONS: Accompanying music therapy reduces requirement of analgesia during colonoscopy, favours completion of the procedure and shortens examination time. Music therapy seems to promote safer conditions for endoscopical practice and diminishs patients discomfort.

Adult↗
PubMed2002

[Nutrition in chronic inflammatory bowl diseases. What your patient tolerates is permitted].

Modifying the diet can have a favorable impact on the course of chronic inflammatory bowel disease. In contrast, nutrition plays no major role in the development of the disease or in provoking an acute attack. During an acute attack of Crohn's disease, the application of oral (drinks) or tube feeding (enteral nutrition) can result in a substantial clinical improvement. The remission rate of this side effect-free therapy is, however, lower than that seen with steroids. The data available for diet therapy in ulcerative colitis are less unequivocal, but the effects are probably slight at best. During the remission phase, the patient should eat a balanced, vitamin-rich and varied normal diet that excludes all poorly tolerated foods: lactose intolerance in particular appears to be increased in patients with Crohn's disease. Known vitamin or mineral deficiencies should be corrected by appropriate dietary measures or supplementation. There is no such thing as a "Crohn's diet" or "colitis diet". The patient can be allowed to eat anything that is tolerated.

Colitis, Ulcerative↗
PubMed2002

[Digital vs. analog hearing aids for children. Is there a method for making an objective comparison possible?].

Until now, the assumed benefits of digital hearing aids are reflected only in subjective descriptions by patients with hearing aids, but cannot be documented adequately by routine diagnostic methods. Seventeen schoolchildren with moderate severe bilateral symmetrical sensorineural hearing loss were examined in a double-blinded crossover study. Differences in performance between a fully digital hearing aid (DigiFocus compact/Oticon) and an analogous digitally programmable two-channel hearing aid were evaluated. Of the 17 children, 13 choose the digital and 4 the analogous hearing aid. In contrast to the clear subjective preferences for the fully digital hearing aid, we could not obtain any significant results with routine diagnostic methods. Using the "virtual hearing aid," a subjective comparison and speech recognition performance task yielded significant differences. The virtual hearing aid proved to be suitable for a direct comparison of different hearing aids and can be used for double-blind testing in a pediatric population.

Child↗
PubMed2002

A biohybrid system to interface peripheral nerves after traumatic lesions: design of a high channel sieve electrode.

Peripheral nerve lesions lead to nerve degeneration and flaccid paralysis. The first objective in functional rehabilitation of these diseases should be the preservation of the neuro-muscular junction by biological means and following functional electrical stimulation (FES) may restore some function of the paralyzed limb. The combination of biological cells and technical microdevices to biohybrid systems might become a new approach in neural prosthetics research to preserve skeletal muscle function. In this paper, a microdevice for a biohybrid system to interface peripheral nerves after traumatic lesions is presented. The development of the microprobe design and the fabrication technology is described and first experimental results are given and afterwards discussed. The technical microprobe is designed in a way that meets the most important technical requirements: adaptation to the distal nerve stump, suitability to combine the microstructure with a containment for cells, and integrated microelectrodes as information transducers for cell stimulation and monitoring. Micromachining technologies were applied to fabricate a polyimide-based sieve-like microprobe with 19 substrate-integrated ring electrodes and a distributed counter electrode. Monolithic integration of fixation flaps and a three-dimensional shaping technology led to a device that might be adapted to nerve stumps with neurosurgical sutures in the epineurium. First experimental results of the durability of the shaping technology and electrochemical electrode properties were investigated. The three-dimensional shape remained quite stable after sterilization in an autoclave and chronic implantation. Electrode impedance was below 200 kOmega at 1 kHz which ought to permit recording of signals from nerves sprouting through the sieve holes.

Animals↗
PubMed2002

A G468-T AMPD1 mutant allele contributes to the high incidence of myoadenylate deaminase deficiency in the Caucasian population.

Myoadenylate deaminase deficiency is the most common metabolic disorder of skeletal muscle in the Caucasian population, affecting approximately 2% of all individuals. Although most deficient subjects are asymptomatic, some suffer from exercise-induced myalgia suggesting a causal relationship between a lack of enzyme activity and muscle function. In addition, carriers of this derangement in purine nucleotide catabolism may have an adaptive advantage related to clinical outcome in heart disease. The molecular basis of myoadenylate deaminase deficiency in Caucasians has been attributed to a single mutant allele characterized by double C to T transitions at nucleotides +34 and +143 in mRNA encoded by the AMPD1 gene. Polymerase chain reaction-based strategies have been developed to specifically identify this common mutant allele and are considered highly sensitive. Consequently, some laboratories preferentially use this technique over other available diagnostic tests for myoadenylate deaminase deficiency. We previously identified a G468-T mutation in one symptomatic patient who was only heterozygous for the common AMPD1 mutant allele. In this report, nine additional individuals with this compound heterozygous genotype are revealed in a survey of 48 patients with documented deficiency of skeletal muscle adenosine monophosphate deaminase and exercise-induced myalgia. Western blot analysis of leftover biopsy material from one of these individuals does not detect any immunoreactive myoadenylate deaminase polypeptide. Baculoviral expression of the G468-T mutant allele produces a Q156H substitution enzyme exhibiting labile catalytic activity. These combined results demonstrate that the G468-T transversion is dysfunctional and further indicate that AMPD1 alleles harboring this mutation contribute to the high incidence of partial and complete myoadenylate deaminase deficiency in the Caucasian population. Consequently, genetic tests for abnormal AMPD1 expression designed to diagnose patients with metabolic myopathy, and to evaluate genetic markers for clinical outcome in heart disease should not be based solely on the detection of a single mutant allele.

AMP Deaminase↗
PubMed2002

Effect of wash bulk on the accuracy of polyvinyl siloxane putty-wash impressions.

Variations in the bulk of wash in a putty-wash impression technique can result in dimensional changes proportional to the thickness of the wash material during setting. The purpose of the study was to determine the amount of wash necessary to achieve accurate stone models while using a two-step putty-wash impression technique with polyvinyl siloxane (PVS) impression material. A total of 45 impressions were made of a stainless steel master model, 15 impressions for each wash thickness (1, 2 and 3 mm). The model contained three full-crown abutment preparations, which were used as the positive control. Accuracy was assessed by measuring six dimensions (occlusogingival and interabutments) on stone dies poured from impressions of the master model. One-way analysis of variance (ANOVA) showed statistically significant differences amongst the three wash bulk groups, for all occlusogingival and interabutment measurements (P < 0.001). The overall discrepancies of the groups using wash thickness of 1 and 2 mm were smaller than the group with 3 mm wash thickness. Therefore, wash bulks of 1 and 2 mm were most accurate for fabricating stone dies, using PVS impression materials. This can be achieved by using the temporary crown to create the desired wash space in the preliminary putty impression. Wash thickness > 2 mm was inadequate to obtain accurate stone dies.

Analysis of Variance↗
PubMed2002

Survey on the use of complementary and alternative medicine among patients with headache syndromes.

The objective was to determine headache patients' knowledge, prevalence of use and perceived effectiveness of complementary and alternative medicine. Seventy-three patients with headache syndromes attending a head and neck pain clinic were interviewed using a standardized questionnaire. Alternative medical therapies were used by 85% of surveyed patients for the relief of their head pain. In 60%, the therapies were perceived to have a benefit. Almost 100% of the patients were familiar with one or more of the presented alternative treatments. Eighty-eight per cent perceived at least one of the complementary treatments to be an effective remedy for headache pain. Exposure to and interest in alternative treatments are common among patients with headache syndromes, despite the lack of scientific evidence of benefit and assessments of risks for many of the treatments. Neurologists and general physicians should be aware of the increasing role of alternative medicine in the healthcare system. There is still an urgent need for objective, integrative and critical research with regard to complementary and alternative medicine.

Adult↗
PubMed2002

[Test set for the evaluation of hearing and speech development after cochlear implantation in children].

BACKGROUND: Since autumn 1998 the multicenter interdisciplinary study group "Test Materials for CI Children" has been compiling a uniform examination tool for evaluation of speech and hearing development after cochlear implantation in childhood. METHODS USED: After studying the relevant literature, suitable materials were checked for practical applicability, modified and provided with criteria for execution and break-off. For data acquisition, observation forms for preparation of a PC-version were developed. RESULTS: The evaluation set contains forms for master data with supplements relating to postoperative processes. The hearing tests check supra-threshold hearing with loudness scaling for children, speech comprehension in silence (Mainz and Göttingen Test for Speech Comprehension in Childhood) and phonemic differentiation (Oldenburg Rhyme Test for Children), the central auditory processes of detection, discrimination, identification and recognition (modification of the "Frankfurt Functional Hearing Test for Children") and audiovisual speech perception (Open Paragraph Tracking, Kiel Speech Track Program). The materials for speech and language development comprise phonetics-phonology, lexicon and semantics (LOGO Pronunciation Test), syntax and morphology (analysis of spontaneous speech), language comprehension (Reynell Scales), communication and pragmatics (observation forms). The MAIS and MUSS modified questionnaires are integrated. CONCLUSIONS: The evaluation set serves quality assurance and permits factor analysis as well as controls for regularity through the multicenter comparison of long-term developmental trends after cochlear implantation.

Child↗
PubMed2002

Reverse mosaicism in Fanconi anemia: natural gene therapy via molecular self-correction.

Fanconi anemia (FA) is a genetically and phenotypically heterogenous autosomal recessive disease associated with chromosomal instability and hypersensitivity to DNA crosslinkers. Prognosis is poor due to progressive bone marrow failure and increased risk of neoplasia, but revertant mosaicism may improve survival. Mechanisms of reversion include back mutation, intragenic crossover, gene conversion and compensating deletions/insertions. We describe the types of reversions found in five mosaic FA patients who are compound heterozygotes for single base mutations in FANCA or FANCC. Intragenic crossover could be shown as the mechanism of self-correction in the FANCC patient. Restoration to wildtype via back mutation or gene conversion of either the paternal or maternal allele was observed in the FANCA patients. The sequence environments of these mutations/reversions were indicative of high mutability, and selective advantage of bone marrow precursor cells carrying a completely restored FANCA allele might explain the surprisingly uniform pattern of these reversions. We also describe a first example of in vitro phenotypic reversion via the emergence of a compensating missense mutation 15 amino acids downstream of the constitutional mutation, which explains the reversion to MMC resistance of the respective lymphoblastoid cell line. With one exception, our mosaic patients showed improvement of their hematological status during a three- to six-year observation period, indicating a proliferative advantage of the reverted cell lineages. In patients with Fanconi anemia, genetic instability due to defective caretaker genes sharply increases the risk of neoplasia, but at the same time increases the chance for revertant mosaicism leading to improved bone marrow function.

Adolescent↗
PubMed2002

[Parelectric spectroscopy for noninvasive diagnosis of laryngeal tissue].

Under the influence of an external electrical field, every biological tissue displays characteristic parelectric properties that can be recorded by radiofrequency spectroscopy in a noninvasive contact mode. Parelectric spectroscopy was investigated for its utility as a complementary noninvasive diagnostic procedure in examinations of the larynx, in particular in terms of its ability to differentiate tissue properties. Parelectric spectroscopy was performed in 10 patients submitted to surgical ablation of vocal cord neoplasia under local or insufflation anaesthesia. Measurements were obtained in the area of the neoplasia, and in macroscopically normal tissue in the corresponding vocal cord. In all cases, intra-individual comparison with normal vocal cord tissue revealed lower dipole density and reduced mobility of the affected vocal cord. In addition, the difference between normal and pathological tissue in terms of the parelectric parameters increased with age. The absolute values of dipolar density and mobility revealed no tendency to correlate with different kinds of vocal cord neoplasia. Parelectric spectroscopy may be a useful additional diagnostic tool for monitoring the course of epithelial changes in the larynx.

Adolescent↗
PubMed2001

Sixteen rare sequence variants of the hMLH1 and hMSH2 genes found in a cohort of 254 suspected HNPCC (hereditary non-polyposis colorectal cancer) patients: mutations or polymorphisms?

5-8% of all colorectal cancer cases are assumed to be due to germline mutations in DNA mismatch repair genes. Mutation analysis of these genes in affected families enables one to identify subjects with an inborn susceptibility to colorectal tumorogenesis and to offer presymptomatic testing to family members at risk, provided that the mutation detected is a truncating one or a missense mutation that has either been judged as disease causing in other families or segregates with the disease and results in a microsatellite instability of the corresponding tumor. Segregation analysis within the family or microsatellite analysis of the tumor is, however, not always possible. In these cases, assessment of the relevance of the sequence variation identified is very difficult. On the other hand, discrimination between inactivating mutations and innocuous sequence polymorphisms is of extreme importance for clinical and genetic counseling of affected families. Here we report 16 rare sequence variants of the hMLH1 and hMSH2 genes including 11 different missense variations found in a cohort of 254 suspected HNPCC patients. We provide evidence, that missense variations in hMLH1 do not necessarily result in microsatellite instability of the corresponding tumor DNA. These patients would have been missed had one followed the recommendations of using only microsatellite analysis for the selection of patients at high risk of hereditary non-polyposis colorectal cancer for mutation analysis.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Pentaporphyrin with flexible, chiral nucleosidic linkers: unexpected duality of the physico-chemical properties of its core.

A new star-like pentaporphyrin, bearing nucleosidic linkers, has been synthesized, and the unexpected duality of the physico-chemical properties of its core is reported; beside the quenching of the fluorescence of the peripheral porphyrins by the central chromophore, this pentaporphyrin exhibits an unexpected shielding of the redox capabilities of its central core.

Journal Article↗