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Biomedical subjects

H Kaiser

Publications and source records attributed to H Kaiser.

At least 37 records · Page 2Linked to original sources
PubMed2002

Chromosome banding in amphibia. XXIII. Giant W sex chromosomes and extremely small genomes in Eleutherodactylus euphronides and Eleutherodactylus shrevei (Anura, Leptodactylidae).

Highly differentiated, heteromorphic ZZ female symbol /ZW male symbol sex chromosomes were found in the karyotypes of the neotropical leptodactylid frogs Eleutherodactylus euphronides and E. shrevei. The W chromosomes are the largest heterochromatic, female-specific chromosomes so far discovered in the class Amphibia. The analyses of the banding patterns with AT- and GC base-pair specific fluorochromes show that the constitutive heterochromatin in the giant W chromosomes consists of various categories of repetitive DNA sequences. The W chromosomes of both species are similar in size, morphology and banding patterns, whereas their Z chromosomes exhibit conspicuous differences. In the cell nuclei of female animals, the W chromosomes form very prominent chromatin bodies (W chromatin). DNA flow cytometric measurements demonstrate clear differences in the DNA content of male and female erythrocytes caused by the giant W chromosome, and also shows that these Eleutherodactylus genomes are among the smallest of all amphibian genomes. The importance of the heteromorphic ZW sex chromosomes for the study of Z-linked genes, the similarities and differences of the two karyotypes, and the significance of the exceptionally small genomes are discussed.

Animals↗
PubMed2001

[Electric nerve stimulation in relation to impulse strength. A quantitative study of the distance of the electrode point to the nerve].

In the present study the difference of the distances of the tip of the needle to the nerve at similar current intensities but different pulse widths (100 microseconds vs. 1000 microseconds) were determined by means of 20 blockades of the sciatic nerve using the transgluteal approach of Labat. Comparable current intensities at different pulse widths (100 microseconds vs. 1000 microseconds) were compared in the same way, using the same position of the needle. At a pulse width of 100 microseconds and a current intensity of 0.30 mA, the tip of the needle is on an average of 5.0 mm closer to the nerve than with a pulse width of 1000 microseconds and a comparable current intensity of 0.28 mA (difference statistically highly significant; p < 0.005). The comparison of the current intensities at different pulse widths at the same needle-position shows that the difference of the current intensities becomes lower when approaching the nerve. At the most distant point measured in this study, a current intensity of 0.94 mA at 100 microseconds corresponds to an aquivalent current of 0.30 mA at 1000 microseconds (difference 0.64 mA); after an approach of 5.0 mm to the sciatic nerve, this difference is significantly lower (0.30 mA at 100 microseconds, 0.11 mA at 1000 microseconds, difference 0.18 mA; p < 0.01). This means that the control of peripheral nerve stimulation is superior at a pulse width of 100 microseconds because a similar distance corresponds to a greater difference of the current. The success rate of the blockade was 95% at a current of 0.30 mA at 100 microseconds. Nerve lesions or other complications have not been seen. In conclusion, safe and successful nerve blocks in patients without polyneuropathia using the peripheral nerve stimulation seems to be obtained at a current intensity of about 0.30 mA at a pulse width of 100 microseconds.

Adolescent↗
PubMed2001

[Biometric data on risk of pneumothorax from vertical infraclavicular brachial plexus block. A magnetic resonance imaging study].

In the present study 48 sagittal and transversal magnetic resonance images of volunteers were examined for biometric data concerning risk of pneumothorax at the vertical infraclavicular blockade (VIP) of the brachial plexus. With a correct puncture the plexus can be reached after 3 cm. The shortest way to the lung is 5.3 cm (3.1-8.7 cm) at a incorrect medial angle of puncture of 46.3 degrees (35-58 degrees). While moving the angle of puncture at a minimum of 24.1 degrees (1-51 degrees) in a medial direction, a depth of 6.1 cm (4-8.9 cm) has to be reached for fatal lung puncture. The puncture point has to be determined 2.8 cm (0-4.1 cm) towards the midline of the body to have a pleura connection by a strictly vertical puncture at 6 cm (4-8.9 cm). In asthenic women, shorter distances were obtained. A considerable lower deviation can lead to pleural damage (7.5 degrees; 4.7 cm). The plexus is very close to the skin surface (1.6-3 cm). In one case, the risk for pneumothorax could be measured even with the correct puncture technique. Overall, the VIP is a very safe method for brachial plexus anaesthesia with regard to the risk of pneumothorax. In asthenic women, the risk seems to be higher but can be minimised by reducing the maximum puncture depth.

Brachial Plexus↗
PubMed2001

Latent carcinoma of the thyroid in Austria: a systematic autopsy study.

Data concerning the incidence of latent thyroid carcinoma (LTC) in populations with endemic goiter are scarce. Despite the introduction of iodine goiter prophylaxis in the early sixties, iodine supply is still insufficient in Austria and goiter remains endemic. This is the first detailed study dealing with epidemiological features of LTC at autopsy in Austria. A total of 118 thyroid glands were included in the study. The glands were serially sectioned at 2- to 3-mm intervals, embedded in paraffin and histologically examined for the presence of LTC. In addition, the incidence and severity of lymphocytic thyroiditis (LT) were evaluated. Ten thyroids were found to contain LTC (8.6%). All were of the papillary type. The mean tumor dimension was 4.9 mm +/- 3.2, the smallest lesion measuring 1 mm. Only the largest tumor slightly exceeded the extent of a microcarcinoma and measured 10.5 mm. Multifocal disease was present in three cases (30%). The prevalence of latent papillary thyroid carcinoma (LPTC) was 6.6% (n = 4) in females and 10.5% (n = 6) in males. The mean age of the subjects with LPTC was 67.7 +/- 14.4 yr, range 37 to 77 yr. Goitrous thyroids were seen in 33 cases (28%): One gland was diffusely enlarged and 32 (27.1%) enlarged glands were nodular goiters. The overall prevalence of LT was 30.5% (n = 36) and the only type of thyroiditis observed was focal lymphocytic thyroiditis (FLT). There was no correlation between the presence of LPTC and goiter, the presence of FLT and the subjects' age and sex. The incidence of LPTC in Austria is similar to that in nongoitrous regions. The adult population at large seems to be uniformly exposed to factors involved in the initiation and early growth of papillary thyroid carcinoma (PTC). This suggests that the levels of iodine intake only play a minor role in the early phase of the carcinogenesis of PTC, but may be of some importance in the progression of LPTC to clinically evident PTC.

Adolescent↗
PubMed2001

Stomatal oscillations at small apertures: indications for a fundamental insufficiency of stomatal feedback-control inherent in the stomatal turgor mechanism.

Continuous measurements of stomatal aperture simultaneously with gas exchange during periods of stomatal oscillations are reported for the first time. Measurements were performed in the field on attached leaves of undisturbed Sambucus nigra L. plants which were subjected to step-wise increases of PPFD. Oscillations only occurred when stomatal apertures were small under high water vapour mole fraction difference between leaf and atmosphere (DeltaW). They consisted of periodically repeated opening movements transiently leading to very small apertures. Measurements of the area of the stomatal complex in parallel to the determination of aperture were used to record volume changes of guard cells even if stomata were closed. Stomatal opening upon a light stimulus required an antecedent guard cell swelling before a slit occurred. After opening of the slit the guard cells again began to shrink which, with some delay, led to complete closure. Opening and closing were rhythmically repeated. The time-lag until initial opening was different for each individual stoma. This led to counteracting movements of closely adjacent stomata. The tendency to oscillate at small apertures is interpreted as being a failure of smoothly damped feedback regulation at the point of stomatal opening: Volume changes are ineffective for transpiration if stomata are still closed; however, at the point of initial opening transpiration rate rises steeply. This discontinuity together with the rather long time constants inherent in the stomatal turgor mechanism makes oscillatory overshooting responses likely if at high DeltaW the 'nominal value' of gas exchange demands a small aperture.

Atmosphere↗
PubMed2000

Maturation and pro-peptide cleavage of beta-secretase.

Amyloid beta-peptide is generated by two sequential proteolytic cleavages mediated by beta-secretase (BACE) and gamma-secretase. BACE was recently identified as a membrane-associated aspartyl protease. We have now analyzed the maturation and pro-peptide cleavage of BACE. Pulse-chase experiments revealed that BACE is post-translationally modified during transport to the cell surface, which can be monitored by a significant increase in the molecular mass. The increase in molecular mass is caused by complex N-glycosylation. Treatment with tunicamycin and N-glycosidase F led to a BACE derivative with a molecular weight corresponding to an unmodified version. In contrast, the mature form of BACE was resistant to endoglycosidase H treatment. The cytoplasmic tail of BACE was required for efficient maturation and trafficking through the Golgi; a BACE variant lacking the cytoplasmic tail undergoes inefficient maturation. In contrast a soluble BACE variant that does not contain a membrane anchor matured more rapidly than full-length BACE. Pro-BACE was predominantly located within the endoplasmic reticulum. Pro-peptide cleavage occurred immediately before full maturation and trafficking through the Golgi.

Amidohydrolases↗
PubMed2000

[Pneumothorax in vertical infraclavicular block of the brachial plexus. Review of a rare complication].

A 50 year old female patient received anaesthesia of the arm by the vertical infraclavicular blockade of the plexus brachialis (VIP). Postoperatively an ipsilateral pneumothorax occurred complicated by pleural effusion and a contralateral bronchopneumonia, which resolved completely after treatment. The blockade of the plexus was performed correctly, failures in determining the correct point of needle insertion could be excluded. Therefore a pneumothorax has to be regarded as a specific complication of the VIP, which might occur despite correct technique, and requires that the patient be informed of this eventuality. Nevertheless, the VIP is an important method due to its high success rate concerning blockade of the musculocutaneous nerve and tolerance of tourniquet. The risk of a pneumothorax is about 0.2 to 0.7%.

Arm↗
PubMed2000

[Corticoids in therapy of rheumatic diseases yesterday--today--tomorrow].

The discovery of the suprarenal glands and their function is discussed. The complicated history of cortisone from the synthesis until its use as an antirheumatic is told. Pharmacotherapy with this physiologic hormone also caused serious side effects. Changing the molecular structure did not essentially solve this problem. Only after finding novel ways of application could these risks be reduced. The indications for therapy were further effectively reduced after understanding the mechanisms of action. Modern standards for corticoid therapy of rheumatoid arthritis are discussed. The important problem of corticoid osteoporosis and the myth of cortisone ulcers are also explained. The problems of coping with patient fears to cortisone are considered. Concurring drugs of cortisone and their special benefits are compared.

Adrenal Cortex Hormones↗
PubMed2000

[Value of the ERGOS work simulator as a component of functional capacity assessment in disability evaluation].

The use of assessment instruments in evaluating functional capacity is an important element in the process of social-medical judgement of whether a person will likely be able to reintegrate into working life. Standardized work processes are used in simulating occupational reality over several hours, with all the requirements involved, and the performance found is contrasted with the requirements to be expected at a workplace. Time-tested in the U.S. for more than 20 years and applied throughout Germany for some two years now, the ERGOS work simulation system is presented in the article, using a case example for more detailed description. Using five different work stations, performance data are collected for job tasks such as carrying, working in kneeling position or overhead, and subjected to computer-based comparison with the job requirements information contained in relevant databases. This enables computerized identification of excessive demands, and hence may point to a need for further rehabilitative action. An important feature is objective assessment, as subjective information on the basis of observation or reports of painfulness are raised separately, hence do not influence the findings of the work simulation performed.

Computer Simulation↗
PubMed2000

[Change in technical aids (AT)--a technology assessment from the viewpoint of rehabilitation-anthropology].

Practical experience in adjusting complex computer-assisted (CAS) communication aids has resulted in a search for prognostic criteria useful in evaluating the efficacy of technical aids. Such evaluation implies a holistic approach as is included in the ICIDH-2. These circumstances are demonstrated by examples ranging from mechanical to computer-assisted (CAS) aids. "Reciprocity" has turned out to be a valid semi-qualitative criterion in describing the dynamic equilibration of the rehabilitative issues involved. Only a dialogical situation with reciprocity will lead to sustainable participation. In case of technical aids, a conjunction of abilities and the qualitative level of activities in disabled people have to be taken into account to provide all dimensions of participation. In this holistic approach, social participation and balance will equally be respected. The differentiation of social systems with unequal consequences for people with disabilities in terms of environmental factors, or e-code of the ICIDH-2, have to be considered for prognostic evaluation with regard to efficacy and possible participation. A comprehensive psycho-socio-functional rating therefore has to include a comparative (socio-structural or morphological) analysis of the environment at hand. This approach will invariably show that technical aids alone are unable to ensure individual independence but, rather, may lead to isolation if there is no regional or local networking based on partnership and close interpersonal relations to be drawn on "technically".

Communication Devices for People with Disabilities↗
PubMed2000

[Value of the Susan Isernhangen Evaluation of Functional Capacity Scale in medical and occupational rehabilitation].

In Germany, Susan Isernhagen's Functional Capacity Evaluation (FCE) system has increasingly come into use over the last few years at the interface between medical and vocational rehabilitation. With implementation of these work-related tests of functional capacity it is possible to obtain valid statements concerning the further vocational prognosis. Along with evaluative testing by experts from different disciplines, the further steps towards integration occur on a well-founded basis. Therapies may thus be adjusted to the requirements of work, either at the former workplace or a new one, or possibly of a vocational (re-)training measure. Also, it is possible to directly deal with work-related issues in the report given at the end of rehabilitation, to initiate preliminary integrative steps in order to achieve a seamless, job retention-focussed transition back into work life. Work is simulated at different levels of loading capacity, the functional deficits of the rehabilitees are addressed in a specific, job-related manner, so as to enable an early return to work after rehabilitation.

Disability Evaluation↗
PubMed2000

In situ observation of stomatal movements and gas exchange of Aegopodium podagraria L. in the understorey.

Observations of stomata in situ while simultaneously measuring CO(2) gas exchange and transpiration were made in field experiments with Aegopodium podagraria in a highly variable light climate in the understorey of trees. The low background photosynthetic photon flux density (PPFD) caused a slight opening of the stomata and no visible response to sporadic lightflecks. However, if lightflecks were frequent and brighter, slow opening movements were observed. Small apertures were sufficient to allow maximal photosynthetic rates. Therefore, the small apertures observed in low light usually only caused minor stomatal limitations of lightfleck photosynthesis. The response of stomata to step-wise changes in PPFD under different levels of leaf to air vapour pressure difference (Delta(W)) was observed under controlled conditions. High Delta(W) influenced the stomatal response only slightly by reducing stomatal aperture in low light and causing a slight reduction in the initial capacity to utilize high PPFD levels. Under continuous high PPFD, however, stomata opened to the same degree irrespective of Delta(W). Under high Delta(W), opening and closing responses to PPFD-changes were faster, which enabled a rapid removal of the small stomatal limitations of photosynthesis initially present in high Delta(W) after longer periods in low light. It is concluded that A. podagraria maintains a superoptimal aperture in low light which leads to a low instantaneous water use efficiency, but allows an efficient utilization of randomly occurring lightflecks.

Carbon Dioxide↗
PubMed2000

Numerical aberrations of chromosome 8 and allelic loss at 8p in non-muscle-invasive urothelial carcinomas of the urinary bladder.

OBJECTIVES: Cytogenetic and molecular studies indicate that the development and progression of bladder cancer involves multiple and complex genetic events. We screened 39 primary T(a )and T(1) transitional cell carcinomas of the urinary bladder for numerical changes of chromosome 8 and for the presence of relative allelic loss at 8p. The results were compared with the histopathologic stage and grade and with tumour recurrence. METHODS: Thirty-nine paraffin-embedded transurethral resection specimens containing bladder cancer were examined by interphase cytogenetics with a probe specific for chromosome 8. DNA from tumour cells and normal tissue was prepared after microdissection. Allelic loss was assessed by PCR-based microsatellite analysis. RESULTS: Numerical aberrations of chromosome 8 were present in 20 of the 39 cases (51.3%) and were significantly associated with a higher tumour grade and stage. Ten cases (25.6%) displayed allelic losses at 8p. Sixteen patients (41%) suffered from tumour recurrence, but Kaplan-Meier analysis and the log-rank test did not show any statistically significant correlation between tumour grade, stage, numerical aberrations of chromosome 8, allelic losses of 8p and freedom from disease recurrence. CONCLUSIONS: In this group of patients with non-muscle-invasive bladder cancers, numerical and structural aberrations at chromosome 8 are associated with a higher tumour grade and stage, but not with tumour recurrence.

Aged↗
PubMed2000

[Profile comparison systems and performance diagnostic, electronic data processing-supported technology--their use in improving responses to social medicine questions and expert assessments and planning of rehabilitation measures].

Systems for comparing ability and requirement profiles as well as instruments for evaluating functional capacity are current topics in rehabilitation. Only few of them however are related to vocational rehab. This article describes the present state of affairs in the development in procedures, instruments and methods to measure work-related human functional capacity with the aim of vocational rehabilitation and integration, helping to obtain objective results to decide about further steps. They are an addition to sociomedical advice in assessment and vocational centres, and serve to expand the common basis of the WHO International Classification of impairments, disabilities and handicaps (ICIDH). The purpose is intervention. Abilities are contrasted with requirements, as the basis for defining a need for intervention and realizing appropriate action. This is the thinking integrated in the German profiling assessment and documentation system IMBA--Integration von Menschen mit Behinderungen in die Arbeitswelt (Integration of people with disabilities into worklife). Diagnostic, computer based technology and work simulation and measurement to evaluate functional capacity as developed and used in the U.S. is complementary to IMBA. Work simulation is based on databases, such as the D.O.T., and includes standardized work requirement profiles. Such systems have been imported from the United States of America to Switzerland and the Netherlands and now to Germany. There are numerous connections with German assessment systems, and the fundamentals of ICIDH are included. Common application in the field of rehabilitation is dealt with, also in view of pensioning issues. The need for user training and quality management are reported in this article as well.

Chronic Disease↗
PubMed2000

Nedocromil sodium 2% ophthalmic solution for the treatment of ragweed pollen seasonal allergic conjunctivitis.

PURPOSE: To determine the efficacy and safety of nedocromil sodium 2% ophthalmic solution in the treatment of seasonal allergic conjunctivitis. METHODS: A combined analysis of two multicenter, randomized, comparative, double-masked, placebo-controlled clinical trials involving 261 patients diagnosed with seasonal allergic conjunctivitis was used. Patients were randomly assigned to receive either topical 2% nedocromil sodium or placebo twice daily for eight weeks. Diary card scores and clinician assessments of allergic symptoms were recorded throughout the study; efficacy was determined by comparing symptom severity at the peak pollen period with symptom severity at baseline. Clinician and patient evaluations of treatment effectiveness were used as secondary measurements of efficacy. RESULTS: Patients treated with nedocromil sodium experienced improvement in allergy symptoms, with reductions in the summary symptom score, itch, redness, conjunctival injection, and conjunctival edema significantly (p<0.05) greater than those observed in the patients treated with placebo. Clinicians' and patients' opinions of nedocromil sodium treatment effectiveness were significantly (p<0.02) superior to those of placebo treatment effectiveness. CONCLUSION: Nedocromil sodium is effective in the management of seasonal allergic conjunctivitis.

Adolescent↗
PubMed1999

Ipratropium bromide nasal spray 0.03% and beclomethasone nasal spray alone and in combination for the treatment of rhinorrhea in perennial rhinitis.

BACKGROUND: Perennial rhinitis is a common condition that affects up to 10% to 20% of the population. Multiple agents are frequently administered since no single agent provides complete relief. Studies assessing the benefit/risk of combined therapy are important especially for newly approved agents such as ipratropium bromide nasal spray 0.03%, a topical anticholinergic agent, approved specifically for the treatment of rhinorrhea in allergic and non-allergic perennial rhinitis. OBJECTIVE: To compare the efficacy and safety of the combined use of ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) and beclomethasone dipropionate nasal spray (84 microg per nostril bid) against that of either active agent alone for the treatment of rhinorrhea. DESIGN: Multicenter, 6-week, double-blind, randomized active- and placebo-controlled, parallel trial. SETTING: Allergist and general practitioner clinical practices. PATIENTS: Five hundred thirty-three patients with perennial rhinitis (279 allergic and 274 non-allergic), 8 to 75 years of age, who had at least a mild degree of severity of rhinorrhea for a minimum of 2 hours per day during the 1 week screening period as well as congestion or sneezing also of at least mild severity. INTERVENTION: Either (1) ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) plus beclomethasone dipropionate nasal spray (84 microg per nostril bid), (2) ipratropium bromide nasal spray 0.03% (42 microg per nostril tid) alone, (3) beclomethasone dipropionate nasal spray (84 microg per nostril bid) alone, or (4) vehicle [matching placebo nasal spray for the ipratropium bromide (2 sprays per nostril tid)] or beclomethasone dipropionate (2 sprays per nostril bid). MAIN OUTCOME MEASURE: Severity and duration of rhinorrhea, and patient and physician global assessment of control of rhinorrhea. RESULTS: Ipratropium bromide nasal spray plus beclomethasone nasal spray was more effective than either active agent alone or vehicle in reducing the average severity and duration of rhinorrhea during 4 weeks of treatment. The advantage of ipratropium bromide plus beclomethasone nasal spray was evident by the first day of combined treatment and continued throughout the 2-week treatment period. Ipratropium bromide nasal spray had a faster onset of action during the first week of treatment and reduced the duration of rhinorrhea more than beclomethasone. Beclomethasone nasal spray was more effective in reducing the severity of congestion and sneezing than ipratropium. In patients who had not responded well to a nasal steroid prior to participation in the study based on a questionnaire administered at screening, ipratropium bromide was as effective in the steroid non-responders as steroid responders, whereas beclomethasone was more effective in steroid responders. Combined active therapy was well tolerated with no increase in adverse events over that seen previously with ipratropium bromide or beclomethasone nasal spray alone. CONCLUSIONS: The combined use of ipratropium bromide nasal spray with beclomethasone dipropionate nasal spray is more effective than either active agent for the treatment of rhinorrhea, and does not result in a potentiation of adverse drug reactions. Ipratropium bromide nasal spray 0.03% alone should be considered in patients for whom rhinorrhea is the primary symptom, and its use in combination with a nasal steroid should be considered in patients where rhinorrhea is one of the predominant symptoms, or in patients with rhinorrhea not fully responsive to other therapy.

Administration, Inhalation↗
PubMed1999

Dose-proportional pharmacokinetics of budesonide inhaled via Turbuhaler.

AIMS: The present pharmacokinetic study was undertaken to determine the dose proportionality of three different doses of budesonide-400 microg, 800 microg or 1600 microg administered twice daily by a dry-powder inhaler (Turbuhaler ) in adult patients with mild asthma. METHODS: A total of 38 patients received budesonide by inhalation, 13 received 400 microg twice daily, 12 received 800 microg twice daily and 13 received 1600 microg twice daily. Mean FEV1 at inclusion was 3.4, 4.0 and 3.9 l min-1 in the three groups, respectively. Blood samples were taken after a single dose, and after 3 weeks of daily treatment, for pharmacokinetic evaluation. Plasma concentrations of budesonide were determined by liquid chromatography plus mass spectrometry. RESULTS: Eleven evaluable patients remained in each dose group. Mean time to peak budesonide plasma concentration (tmax ) was short (0.28-0.40 h) and did not differ between treatment groups. Budesonide concentrations declined rapidly thereafter, indicating efficient pulmonary absorption and rapid elimination with a half-life of approximately 3 h. Cmax was 1. 4(2.0) nmol l-1 (single (repeated) doses), 2.6(3.6) nmol l-1 and 5. 4(6.4) nmol l-1 after 400, 800 and 1600 microg twice daily, respectively. The corresponding results for the area under the plasma concentration vs time curve (AUC) were 271(325), 490(628) and 915(1096) nmol l-1 min. Ninety percent confidence intervals for pairwise dose-normalized Cmax and AUC comparisons between groups were large but contained unity in all cases, thus indicating dose-proportional pharmacokinetics. Regression on analysis supported these findings. Mean AUC after repeated doses (AUC(0,12 h,RD)) was on average 23% higher than the mean AUC after single doses (AUC(0, infinity,SD)(P=0.04) with no significant differences between doses, indicating slight accumulation following bid dosing. CONCLUSIONS: In this relatively small study, budesonide inhaled via Turbuhaler appeared to have dose-proportional pharmacokinetics, both within and above the clinically recommended dose range for asthmatic patients.

Administration, Inhalation↗