Shot-noise detection of ultrasound-tagged photons in ultrasound-modulated optical imaging

We propose a new detection method for ultrasound-modulated optical tomography that allows us to perform parallel speckle detection with optimum shot-noise sensitivity, using a CCD camera. Moreover, we show that making use of a spatial filter system allows us to fully filter out speckle decorrelation noise. This method is confirmed by a test experiment.

Complete dynamic repopulation of decellularized heart valves by application of defined physical signals—an in vitro study

OBJECTIVE

Cardiovascular tissue engineering is a novel concept to develop ideal heart valve substitutes. The objective of this study was to use decellularized porcine pulmonary valves, ovine cells and dynamic tissue culture to obtain viable and biomechanically stable constructs, resembling native aortic heart valves.

METHODS

Endothelial cells and myofibroblasts were obtained from ovine carotid arteries. Porcine pulmonary valves were decellularized enzymatically, reseeded and cultured using a hydrodynamic bioreactor system over a time period of 9 or 16 days. Controls were grown over an equivalent time period under static conditions. Specimens of each valve were examined biochemically (cell proliferation, DNA, collagen, 4-hydroxyproline, elastin and glycosaminoglycans), histologically (hematoxylin-eosin, Movat-pentachrome and immunostains) and mechanically (radial and circumferential strength).

RESULTS

Histology and biochemical assays demonstrated the removal of almost all cells after decellularization with preservation of the extracellular matrix. Recellularization under pulsatile conditions was significantly improved after 9 and 16 days compared to static conditions. Biochemical and mechanical analysis revealed a continuous increase of cell mass, collagen and elastin contents and strength under pulsatile culture conditions compared to significantly lower values in the static controls.

CONCLUSION

This study demonstrated the superiority of the hydrodynamic approach of cellular reseeding to replace decellularized porcine heart valves with ovine cells with almost complete preservation of extracellular matrix integrity.

Image guided navigation system-a new technology for complex endoscopic endonasal surgery

PURPOSE

Endoscopic endonasal surgery (EES) has become the standard practice in sinonasal and anterior skull base surgery. The purpose of this manuscript is to describe experience using a new technology-the image guided navigation system (IGNS)-in complex cases undergoing EES. The advantages and disadvantages of computer aided surgery are discussed.

PATIENTS AND METHODS

A total of 165 endoscopic endonasal procedures were performed between April 2001 and January 2003. IGNS was used in 34 patients in whom it was assumed that the ability to identify surgical sites accurately could be compromised by previous surgery, massive recurrent polyposis, or abnormal anatomy, or when biopsies had to be taken from specific anatomic locations (for example, clivus, wall of sphenoid sinus, orbital apex). The precision of the navigation system, total operating room time, surgeon's satisfaction and confidence, and intraoperative and postoperative complications were recorded.

RESULTS

In 33 out of 34 patients the surgical procedure was uneventful. One patient with an atelectatic maxillary sinus developed a minor complication of preseptal orbital haematoma. In 94% the IGNS provided accurate anatomical localisation with less than 2 mm localisation error (1.1-2.0 mm, mean 1.6 mm). In all cases the surgical team felt that the system increased the intraoperative safety factor for the patient. The overall operating room time at the end of the study was 15 minutes longer than when regular EES was used.

CONCLUSIONS

IGNS enables a new level of efficiency and safety in EES. Nevertheless, it is not advised for surgeons who are not familiar with regular EES. For the experienced endoscopist, however, IGNS is a valuable new tool in complex procedures.

Image guided navigation system—a new technology for complex endoscopic endonasal surgery

Purpose

Endoscopic endonasal surgery (EES) has become the standard practice in sinonasal and anterior skull base surgery. The purpose of this manuscript is to describe experience using a new technology—the image guided navigation system (IGNS)—in complex cases undergoing EES. The advantages and disadvantages of computer aided surgery are discussed.

Patients and methods

A total of 165 endoscopic endonasal procedures were performed between April 2001 and January 2003. IGNS was used in 34 patients in whom it was assumed that the ability to identify surgical sites accurately could be compromised by previous surgery, massive recurrent polyposis, or abnormal anatomy, or when biopsies had to be taken from specific anatomic locations (for example, clivus, wall of sphenoid sinus, orbital apex). The precision of the navigation system, total operating room time, surgeon’s satisfaction and confidence, and intraoperative and postoperative complications were recorded.

Results

In 33 out of 34 patients the surgical procedure was uneventful. One patient with an atelectatic maxillary sinus developed a minor complication of preseptal orbital haematoma. In 94% the IGNS provided accurate anatomical localisation with less than 2 mm localisation error (1.1–2.0 mm, mean 1.6 mm). In all cases the surgical team felt that the system increased the intraoperative safety factor for the patient. The overall operating room time at the end of the study was 15 minutes longer than when regular EES was used.

Conclusions

IGNS enables a new level of efficiency and safety in EES. Nevertheless, it is not advised for surgeons who are not familiar with regular EES. For the experienced endoscopist, however, IGNS is a valuable new tool in complex procedures.

[67-year-old patient with upper gastrointestinal bleeding]

A 67-year-old patient with upper gastrointestinal bleeding. HISTORY AND CLINICAL FINDINGS: A 67-year old patient with melaena and anaemia (haemoglobin 4.8 g/dl) for 14 days had been admitted to hospital under suspicion of upper gastrointestinal bleeding. The patient had a history of 2/3 resection of the stomach for recurrent duodenal ulcer and of a right nephrectomie for hypernephroma 18 years ago. There was no abdominal pain on pressure, nor muscular guarding. INVESTIGATIONS: Endoscopy (oesophago-duodenoscopie, coloscopie), radiography (angiography, gastrografin passage) and ultrasound failed to locate the source of bleeding. TREATMENT AND COURSE: After repeated endoscopic attempts to localize the source of bleeding and growing need of transfusions (12 blood-concentrates in 5 days) an exploratory laparotomie was done. Surprisingly a bleeding fistula between the stump of the right renal arteria and duodenum was found. The defects were excised and directly closed. CONCLUSIONS: Secondary aortoduodenal fistula after nephrectomy is rare. If the source of bleeding can't be found, and there is in any doubt an exploratory laparotomy should be done.

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.

Heat-shock protein HSP70-2 genotypes in patients with Crohn's disease: a more severe clinical course with intestinal complications in presence of the PstI-polymorphism

BACKGROUND

70 kDa Heat shock proteins are involved in mucosal protecting reactions in the gut of patients with inflammatory bowel disease. Recently, a single nucleotide polymorphism (PstI, nucleotide 1267) was associated with intestinal perforations and formation of abscesses and fistulas in Japanese patients with Crohn's disease. Our purpose was to evaluate this phenomenon in Caucasian patients with Crohn's disease and to verify the clinical importance of this polymorphism.

PATIENTS AND METHODS

61 consecutive patients with Crohn's disease and 61 healthy control persons were examined. After DNA extraction and PCR amplification spanning the PstI-site, restriction fragment length polymorphism analyses (RFLP) were performed. Homozygous and heterozygous genotypes (AA, AB, BB) were then correlated with the clinical characteristics of the patients, especially with their intestinal complications.

RESULTS

Intestinal perforations and formation of fistulas, abscesses and conglomerate tumors were significantly associated with allele B (p = 0.04). Patients with genotype BB showed the highest prevalence for surgical interventions (82%), whereas patients with genotype AA had the lowest prevalence (56%). Onset of disease, the need for immunosuppressive therapy and the occurrence of extraintestinal manifestations did not differ between the three genotypes. Allele A was significantly associated with combined involvement of ileum and colon.

CONCLUSION

Caucasian patients carrying the HSP70-2 PstI-polymorphism seem to have a more severe form of Crohn's disease (perforations, abscesses, fistulas, conglomerate tumors). Especially, the homozygous genotype (BB) predisposes for a clinical course with high risk of surgical intervention.

Randomised controlled trial of site specific advice on school travel patterns

AIMS

To evaluate the effect of site specific advice from a school travel coordinator on school travel patterns.

METHODS

Cluster randomised controlled trial of children attending 21 primary schools in the London boroughs of Camden and Islington. A post-intervention survey measured the proportion of children walking, cycling, or using public transport for travel to school, and the proportion of parents/carers very or quite worried about traffic and abduction. The proportion of schools that developed and implemented travel plans was assessed.

RESULTS

One year post-intervention, nine of 11 intervention schools and none of 10 control schools had travel plans. Proportions of children walking, cycling, or using public transport on the school journey were similar in intervention and control schools. The proportion of parents who were very or quite worried about traffic danger was similar in the intervention (85%) and control groups (87%). However, after adjusting for baseline and other potential confounding factors we could not exclude the possibility of a modest reduction in parental concern about traffic danger as a result of the intervention.

CONCLUSIONS

Having a school travel coordinator increased the production of school travel plans but there was no evidence that this changed travel patterns or reduced parental fears. Given the uncertainty about effectiveness, the policy of providing school travel coordinators should only be implemented within the context of a randomised controlled trial.

[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.

[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.

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.

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.

Thyroid hypoechogenicity in patients with chronic hepatitis receiving interferon-alpha therapy: evaluation by standardized grey scale ultrasonography

BACKGROUND

Recombinant human interferon-a therapy of chronic hepatitis B and C is associated with the induction of thyroid dysfunction in up to 15%. Little is known about morphological changes of the thyroid gland, especially about its tissue echogenicity under this immunomodulative drug treatment.

METHODS

116 patients with chronic hepatitis B or C were consecutively investigated. 53 patients qualified for treatment with interferon-a alone or in combination with ribavirin. Patients with normal serum aminotransferase levels, advanced liver cirrhosis, hepatocellular carcinoma, active intravenous drug or alcohol abusus and with focal thyroid lesions (nodes, cysts, calcifications) were excluded. Thyroid function was determined by measurements of FT4, TSH and thyroidal autoantibodies. Ultrasonography was performed before, during and after interferon-a therapy including volumetry and standardized grey scale analysis. The data were compared with values of 100 euthyroid volunteers as control group.

RESULTS

After six months of therapy patients differed from controls by significant TSH elevation (12.8 +/- 9.34 vs. 2.8 +/- 1.1 microU/ml, p<0.02). Six patients (11%) developed overt hypothyroidism with detectable thyroidal autoantibodies. Thyroid volume in patients was similar (13.0 +/- 4.1 ml) to that in the control group (12.6 +/- 4.7 ml). However, thyroid echogenicity of the patients was significantly lower after 6 months of therapy (21.9 +/- 2.5 grey scales) compared to the status before (25.6 +/- 2.3 grey scales) and compared to the values of controls (25.4 +/- 2.1 grey scales, p <0.002).

CONCLUSION

Beside of functional disorders interferon-alpha leads to thyroid hypoechogenicity suggesting relevant morphological changes of the organ.

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.

[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.

[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.

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.

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.

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.

[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.

Vasculopathy and amyloid beta reactivity in brains of patients with acquired immune deficiency (AIDS)

The authors examined multiple brain sections from 15 autopsy cases of AIDS for the vascular changes, presence of amyloid plaques and signs of axonal damage. The mean patients age was 33.8 years (range 24-48 years). Neuropathological findings included: HIV-specific changes (5), opportunistic infections (7), lymphoma (1) and two cases with nonspecific changes. All sections were stained with hematoxylin-eosin (H-E), selected sections were stained with Masson trichrome, Gomori reticulin, Congo red and thioflavine S method. Two sections from each case were immunostained for the presence of beta-amyloid (4G8). ubiquitin, alpha-smooth muscle actin and CD31. The different forms of vascular changes were found in all cases. The common changes were: lymphocytic perivascular or transmural infiltrations and hyalinization, thickening or fibrosis of the arterial and arteriolar wall. The perivascular space widening up to status lacunaris was a frequent phenomenon in the basal ganglia and deep white matter. Some of the cortical arterioles formed little multiluminal structures. Immunohistochemical examination revealed features of hypertrophy of the vascular muscular layer and signs of the slight endothelial cells proliferation. In three cases 4G8 immunopositive. Congo red and thioflavine S-negative, diffuse beta-amyloid deposits were present in the gray matter, focally their localization was perivascular. Ubiquitin immunoreactivity presented as numerous dot-like structures or focal bundles of positive widened axons in the white matter, spheroids and scattered positive neurons were also found. The authors suggest that some of morphological changes within the brain and consecutive neuropsychological symptoms in AIDS are of the vascular origin. Presence of amyloid plaques and axonal damage are the elements of the complex degenerative and inflammatory process in the brain caused by chronic inflammatory stimulation in HIV infection.

Towards multiporphyrinic alpha-helices with a polypeptidic backbone as system endowed with light harvesting capabilities

Starting from a porphyrin functionalized derivative of the L-lysine, three peptides, bearing, respectively, two, four, and eight chromophores, were synthesized using an iterative synthetic strategy based on the choice of mild conditions for the deprotection steps.

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.

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.

Predicting the success of retrograde stenting for managing ureteral obstruction

PURPOSE

Retrograde ureteral stenting is often considered the first line option for relieving ureteral obstruction when temporary drainage is indicated. Several retrospective studies have implied that in cases of extrinsic obstruction retrograde ureteral stenting may fail and, therefore, percutaneous nephrostomy drainage is required. We examined the efficacy of retrograde ureteral stenting for resolving ureteral obstruction and identified clinical and radiological parameters predicting failure.

MATERIALS AND METHODS

Enrolled in our prospective study were 92 consecutive patients with ureteral obstruction, which was bilateral in 8. Retrograde ureteral stenting was attempted in all cases by the urologist on call. When stent insertion failed, drainage was achieved by percutaneous nephrostomy. Patients were followed at 3-week intervals for 3 months. Each followup visit included a medical interview, blood evaluation, urine culture and ultrasound. Stent malfunction was defined as continuous flank pain manifesting as recurrent episodes of acute renal colic, 1 or more episodes of pyelonephritis, persistent hydronephrosis or elevated creatinine. Preoperative data and outcomes were compared in cases of intrinsic and extrinsic obstruction. Univariate and multivariate analysis was done to identify predictors of the failure of ureteral stent insertion and long-term function.

RESULTS

The etiology of obstruction was intrinsic in 61% of patients and extrinsic in 39%. Extrinsic obstruction, which was associated with a greater degree of hydronephrosis, was located more distal. Retrograde ureteral stenting was successful in 94% and 73% of patients with intrinsic and extrinsic obstruction, respectively. At the 3-month followup stent function was maintained in all patients with intrinsic obstruction but in only 56.4% with extrinsic obstruction. On multivariate logistic regression the type of obstruction, level of obstruction and degree of hydronephrosis were the only predictors of stent function at 3 months. Stent diameter and preoperative creatinine had no predictive value.

CONCLUSIONS

Retrograde ureteral stenting is a good solution for most acutely obstructed ureters. In patients with extrinsic ureteral obstruction a more distal level of obstruction and higher degree of hydronephrosis are associated with a greater likelihood of stent failure. These patients may be better served by percutaneous drainage.

An initial assessment of the optical properties of human laryngeal tissue

The optical properties of human laryngeal tissue have been examined over the whole wavelength range from 400 to 2,200 nm to facilitate the development of new laser applications. Tissue samples were taken from healthy vocal fold and from vocal fold of patients with papillomatosis and with chronic, nonspecific laryngitis. The transmission and scattering properties of the tissue samples were recorded with a computer-guided integrating-sphere system. From the measured data the optical properties were calculated by means of the inverse Monte Carlo simulation. In the 500- to 600-nm range papilloma tissues had a considerably higher absorption than healthy vocal fold. When applying the optical tissue properties as a possible influencing factor of the effectiveness of laser systems, laser applications at this wavelength range may be useful in the ablation of papilloma tissue.

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.

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.

[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.

Equilibration of methionine into the Met-tRNA pool of rabbit reticulocyte lysates

We have measured the rate of equilibration of [35S]methionine into the Met-tRNA pool of rabbit reticulocyte lysate as in [FEBS Lett. (1982) 143, 301-305]. Our results indicate that hemin-deficiency inhibits the equilibration of methionine into the tRNA pool much less than protein synthesis or the equilibration of alanine into the tRNA pool, whereas cycloheximide inhibits these processes similarly. This finding is consistent with our previous data and supports the hypothesis that with hemin-deficiency much of the Met-tRNAf that becomes bound to 40 S subunits subsequently undergoes enzymatic deacylation.