Biomedical subjects

J Kern

Publications and source records attributed to J Kern.

At least 19 recordsLinked to original sources

PubMed2006

First case of febrile bacteremia due to a wild type and small-colony variant of Escherichia coli.

Reported here is a case of a febrile illness caused by a wild type and small-colony variant of Escherichia coli in an anorectic patient. A review of the literature revealed that the formation of small-colony variants in E. coli has been recognized since 1931. In recent years, an association has been established between those variants and chronic recurrent infections. This report describes for the first time the isolation of an E. coli small-colony variant from a blood culture of a patient who had suffered from chronic urinary tract infections in the past.

Adult↗

PubMed2006

Diagnosis of invasive aspergillosis and mucormycosis in immunocompromised patients by seminested PCR assay of tissue samples.

Aspergillosis and mucormycosis are the most common mold infections in patients with hematological malignancies. Infections caused by species of the genus Aspergillus and the order Mucorales require different antifungal treatments depending on the in vitro susceptibility of the causative strain. Cultures from biopsy specimens frequently do not grow fungal pathogens, even from histopathologically proven cases of invasive fungal infection. Two seminested PCR assays were evaluated by amplifying DNA of zygomycetes and Aspergillus spp. from organ biopsies of 21 immunocompromised patients. The PCR assays correctly identified five cases of invasive aspergillosis and six cases of mucormycosis. They showed evidence of double mold infection in two cases. Both assays were negative in five negative controls and in two patients with yeast infections. Sequencing of the PCR products was in accordance with culture results in all culture-positive cases. In six patients without positive cultures but with positive histopathology, sequencing suggested a causative organism. Detection of fungal DNA from biopsy specimens allows rapid identification of the causative organism of invasive aspergillosis and mucormycosis. The use of these PCR assays may allow guided antifungal treatment in patients with invasive mold infections.

Adult↗

PubMed2006

Treatment of recycled carrot washing water.

Large volumes of effluents and solid waste derive from industrial fresh packing and processing of carrots. Due to high organic loads and suspended solids and due to insufficient wastewater treatment, surface waters are polluted by effluents of carrot washing, as shown for one enterprise in Germany. Over a period of four months the water quality was studied at the stages of a treatment system consisting of a grit chamber, a settling tank combined with aeration devices and a constructed wetland. Organic pollutants were measured as COD and BOD5 in different fractions of the wastewater. The daily washing of carrots produces up to 300 m3 wastewater with a mean filterable solids content of 453 mg l(-1) and a mean COD concentration of 179 mg l(-1). On average the current efficiency of total COD reduction is 52%. Due to the fine grain size and the low density of suspended solids, settling is very slow and incomplete, primarily during the winter. As much as 29 mg COD l(-1) in the effluent derive from the fraction of particles which do not settle within 18 hours. The dissolved COD fraction accounts for 30 mg l(-1) and reflects the insufficient oxygenation of the wastewater. Strategies for enhancing the removal of organic compounds can be derived from the results of this study. Spatial separation of settling and aeration processes is recommended to optimise the treatment process. Furthermore, the area of the constructed wetland should be increased to maintain its hydraulic conductivity and to guarantee a high COD reduction.

Biodegradation, Environmental↗

PubMed2005

Herbicide binding and thermal stability of photosystem II isolated from Thermosynechococcus elongatus.

Binding of herbicides to photosystem II inhibits the electron transfer from Q(A) to Q(B) due to competition of herbicides with plastoquinone bound at the Q(B) site. We investigated herbicide binding to monomeric and dimeric photosystem II core complexes (PSIIcc) isolated from Thermosynechococcus elongatus by a combination of different methods (isothermal titration and differential scanning calorimetry, CD spectroscopy and measurements of the oxygen evolution) yielding binding constants, enthalpies and stoichiometries for various herbicides as well as information regarding stabilization/destabilization of the complex. Herbicide binding to detergent-solubilized PSIIcc can be described by a model of single independent binding sites present on this important membrane protein. Interestingly, binding stoichiometries herbicide:PSIIcc are lower than 1:1 and vary depending on the herbicide under study. Strong binding herbicides such as terbutryn stabilize PSIIcc in thermal unfolding experiments and endothermically binding herbicides like ioxynil probably cause large structural changes accompanied with the binding process as shown by differential scanning calorimetry experiments of the unfolding reaction of PSIIcc monomer in the presence of ioxynil. In addition we studied the occupancy of the Q(B) sites with plastoquinone (PQ9) by measuring flash induced fluorescence relaxation yielding a possible explanation for the deviations of herbicide binding from a 1:1 herbicide/binding site model.

Binding Sites↗

PubMed2005

CPPD crystal deposition disease in patients with rheumatoid arthritis.

The aim of this study was to assess the frequency and the outcome of patients suffering from rheumatoid arthritis in which calcium pyrophosphate dihydrate (CPPD) crystal deposits were found to coexist in synovial fluid analysis. Such association was more frequent than previously believed with CPPD crystals found in 25.8% of 93 patients with rheumatoid arthritis. As a group, a trend toward a worse outcome was suggested by more frequent prostheses of the lower limb.

Adult↗

PubMed2005

Purification, characterisation and crystallisation of photosystem II from Thermosynechococcus elongatus cultivated in a new type of photobioreactor.

The thermophilic cyanobacterium Thermosynechococcus elongatus was cultivated under controlled growth conditions using a new type of photobioreactor, allowing us to optimise growth conditions and the biomass yield. A fast large-scale purification method for monomeric and dimeric photosystem II (PSII) solubilized from thylakoid membranes of this cyanobacterium was developed using fast protein liquid chromatography (FPLC). The obtained PSII core complexes (PSIIcc) were analysed for their pigment stoichiometry, photochemical and oxygen evolution activities, as well as lipid and detergent composition. Thirty-six chlorophyll a (Chla), 2 pheophytin a (Pheoa), 9+/- 1 beta-carotene (Car), 2.9+/-0.8 plastoquinone 9 (PQ9) and 3.8+/-0.5 Mn were found per active centre. For the monomeric and dimeric PSIIcc, 18 and 20 lipid as well as 145 and 220 detergent molecules were found in the detergent shell, respectively. The monomeric and dimeric complexes showed high oxygen evolution activity with 1/4 O(2) released per 37-38 Chla and flash in the best cases. Crystals were obtained from dimeric PSIIcc by a micro-batch method. They diffract synchrotron X-rays to a maximum resolution of 2.9-A, resulting in complete data sets of 3.2 A resolution.

Biomass↗

PubMed2005

PCR based identification and discrimination of agents of mucormycosis and aspergillosis in paraffin wax embedded tissue.

BACKGROUND: Invasive fungal infections are often diagnosed by histopathology without identification of the causative fungi, which show significantly different antifungal susceptibilities. AIMS: To establish and evaluate a system of two seminested polymerase chain reaction (PCR) assays to identify and discriminate between agents of aspergillosis and mucormycosis in paraffin wax embedded tissue samples. METHODS: DNA of 52 blinded samples from five different centres was extracted and used as a template in two PCR assays targeting the mitochondrial aspergillosis DNA and the 18S ribosomal DNA of zygomycetes. RESULTS: Specific fungal DNA was identified in 27 of 44 samples in accordance with a histopathological diagnosis of zygomycosis or aspergillosis, respectively. Aspergillus fumigatus DNA was amplified from one specimen of zygomycosis (diagnosed by histopathology). In four of 16 PCR negative samples no human DNA was amplified, possibly as a result of the destruction of DNA before paraffin wax embedding. In addition, eight samples from clinically suspected fungal infections (without histopathological proof) were examined. The two PCR assays detected a concomitant infection with Absidia corymbifera and A fumigatus in one, and infections with Rhizopus arrhizus and A fumigatus in another two cases. CONCLUSIONS: The two seminested PCR assays described here can support a histopathological diagnosis of mucormycosis or aspergillosis, and can identify the infective agent, thereby optimising antifungal treatment.

Aspergillosis↗

PubMed2004

How to keep a wet preparation of synovial fluid.

Identification of crystals in the synovial fluid (SF) is mandatory for the diagnosis of a microcrystal deposition arthropathy. In some cases, this analysis can be troublesome, especially in medical centers where a qualified practitioner is not continually present. Therefore, we investigated a method for preservation of a wet preparation of SF for 24 hours at room temperature. The procedure consisted in storing the preparation in a closed Petri plate whose bottom was covered by a cellulose compress moistened with saline (0.9% sodium chloride) separated from the slide by 2 wooden or glass sticks. The joint aspirates of 20 consecutive patients with various microcrystal arthropathies were read immediately after aspiration and reviewed after 24 hours on the slides stored according to the previously mentioned procedure. For 11 of the 20 cases, a second SF preparation was stored in normal conditions. The amounts of crystals were estimated semiquantitatively.Preparations stored in the Petri plates were clearly readable after 24 hours and crystals still identifiable on each slide. The amounts of crystals were still the same. After 24 hours, the preparations stored in normal conditions were dry, the shapes of the crystals were blurred, their amount was reduced, and birefringent artifacts were seen. In conclusion, when the amounts of SF are small and a skilled technician or a rheumatologist is not immediately available for reading the preparation, storing the wet preparation of SF in a moistened Petri plate can prove useful.

Journal Article↗

PubMed2001

Photosystem II single crystals studied by EPR spectroscopy at 94 GHz: the tyrosine radical Y(D)(*).

Electron paramagnetic resonance (EPR) spectroscopy at 94 GHz is used to study the dark-stable tyrosine radical Y(D)(*) in single crystals of photosystem II core complexes (cc) isolated from the thermophilic cyanobacterium Synechococcus elongatus. These complexes contain at least 17 subunits, including the water-oxidizing complex (WOC), and 32 chlorophyll a molecules/PS II; they are active in light-induced electron transfer and water oxidation. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with four PS II dimers per unit cell. High-frequency EPR is used for enhancing the sensitivity of experiments performed on small single crystals as well as for increasing the spectral resolution of the g tensor components and of the different crystal sites. Magnitude and orientation of the g tensor of Y(D)(*) and related information on several proton hyperfine tensors are deduced from analysis of angular-dependent EPR spectra. The precise orientation of tyrosine Y(D)(*) in PS II is obtained as a first step in the EPR characterization of paramagnetic species in these single crystals.

Crystallization↗

PubMed2001

Crystal structure of photosystem II from Synechococcus elongatus at 3.8 A resolution.

Oxygenic photosynthesis is the principal energy converter on earth. It is driven by photosystems I and II, two large protein-cofactor complexes located in the thylakoid membrane and acting in series. In photosystem II, water is oxidized; this event provides the overall process with the necessary electrons and protons, and the atmosphere with oxygen. To date, structural information on the architecture of the complex has been provided by electron microscopy of intact, active photosystem II at 15-30 A resolution, and by electron crystallography on two-dimensional crystals of D1-D2-CP47 photosystem II fragments without water oxidizing activity at 8 A resolution. Here we describe the X-ray structure of photosystem II on the basis of crystals fully active in water oxidation. The structure shows how protein subunits and cofactors are spatially organized. The larger subunits are assigned and the locations and orientations of the cofactors are defined. We also provide new information on the position, size and shape of the manganese cluster, which catalyzes water oxidation.

Chlorophyll↗

PubMed2001

Respiratory function in active firefighters.

BACKGROUND: Exposure to environmental pollution during firefighting may results in the development of respiratory disorders in firefighters. METHODS: The health effects of firefighting on respiratory function was investigated in a group of 128 active firefighters by recording respiratory symptoms and measuring lung function. In addition, 88 control workers, not exposed to known pollutants were studied for the prevalence of acute and chronic respiratory symptoms. RESULTS: Significantly higher prevalences of dyspnea, nasal catarrh, sinusitis, and hoarseness were recorded in firefighters compared to control workers (P < 0.01). One subject developed asthma symptoms following two intense firefighting episodes. A high prevalence of acute symptoms experienced during and after fire extinguishing was also documented among these firefighters. Eye and throat irritation as well as headache were prominent. A logistic regression analysis of chronic respiratory symptoms demonstrated that odds ratios were significant for both duration of work exposure and for smoking. Lung function testing demonstrated a decrease in FEF75 in relation to predicted suggesting obstructive changes in the smaller airways. A regression analysis of ventilatory capacity tests indicated a positive relationship of forced vital capacity with length of employment, 1 s forced expiratory volume as well as FEF50 were related to smoking, and FEF75 was related to both smoking and length of employment. CONCLUSIONS: Our data suggest that firefighters are at risk for developing acute and chronic respiratory symptoms as well as obstructive airway changes.

Adult↗

PubMed2001

Evaluation of prenatal ultrasound diagnosis of fetal abdominal wall defects by 19 European registries.

OBJECTIVES: To evaluate the current effectiveness of routine prenatal ultrasound screening in detecting gastroschisis and omphalocele in Europe. DESIGN: Data were collected by 19 congenital malformation registries from 11 European countries. The registries used the same epidemiological methodology and registration system. The study period was 30 months (July 1st 1996-December 31st 1998) and the total number of monitored pregnancies was 690,123. RESULTS: The sensitivity of antenatal ultrasound examination in detecting omphalocele was 75% (103/137). The mean gestational age at the first detection of an anomaly was 18 +/- 6.0 gestational weeks. The overall prenatal detection rate for gastroschisis was 83% (88/106) and the mean gestational age at diagnosis was 20 +/- 7.0 gestational weeks. Detection rates varied between registries from 25 to 100% for omphalocele and from 18 to 100% for gastroschisis. Of the 137 cases of omphalocele less than half of the cases were live births (n = 56; 41%). A high number of cases resulted in fetal deaths (n = 30; 22%) and termination of pregnancy (n = 51; 37%). Of the 106 cases of gastroschisis there were 62 (59%) live births, 13 (12%) ended with intrauterine fetal death and 31 (29%) had the pregnancies terminated. CONCLUSIONS: There is significant regional variation in detection rates in Europe reflecting different policies, equipment and the operators' experience. A high proportion of abdominal wall defects is associated with concurrent malformations, syndromes or chromosomal abnormalities, stressing the need for the introduction of repeated detailed ultrasound examination as a standard procedure. There is still a relatively high rate of elective termination of pregnancies for both defects, even in isolated cases which generally have a good prognosis after surgical repair.

Abortion, Induced↗

PubMed2001

Does cisapride influence cardiac rhythm? Results of a United States multicenter, double-blind, placebo-controlled pediatric study.

BACKGROUND: Major concerns about serious cardiac side effects underlie the recent decision by the FDA and Janssen Pharmaceutica (Titusville, NJ) to make cisapride available only through a limited access program. Concerns have grown despite the fact that most instances of prolonged QTc and other ventricular arrhythmias occurred while the drug was used concomitantly with contraindicated drugs. This study sought to analyze electrocardiograms (ECGs) from a multicenter pediatric study and to identify abnormalities in QTc interval associated with cisapride use. METHODS: Children between 6 months and 4 years of age were enrolled if they manifested symptoms of gastroesophageal reflux not responding to medical therapy for at least 6 weeks. In 49 subjects, ECGs obtained before and after randomization to receive 0.2 mg/kg dose three times daily or placebo were reviewed independently and blindly by two pediatric cardiologists. Placebo and active drug groups were compared for QTc and for change in QTc from baseline values after 3 to 8 weeks of treatment. RESULTS: Mean QTc among patients taking the drug was 408+/-18 ms. None was higher than 450 ms. Change between baseline and subsequent QTc at 3 to 8 weeks of treatment was 2+/-20 ms. CONCLUSIONS: In our study group of children without underlying cardiac disease or electrolyte imbalance, cisapride was found to have no significant effect on cardiac electrical function compared with placebo. These results are consistent with the drug's record of exceedingly infrequent cardiac events. Because the availability of this prokinetic is threatened, its safety and the safety and efficacy of alternative treatment options (including surgery) should be studied further.

Arrhythmias, Cardiac↗

PubMed2001

Respiratory findings in livestock farmworkers.

In this cross-sectional study, the prevalence of acute and chronic respiratory symptoms and lung function were investigated in 236 (169 male and 67 female) livestock farmworkers raising domestic animals, including cattle and horses. The prevalence of acute and chronic respiratory symptoms was recorded by administering a modified version of the British Medical Research Council questionnaire on respiratory symptoms. Lung function was measured by recording the maximum expiratory flow-volume curves from which the forced vital capacity, the one-second forced expiratory volume, and the maximum expiratory flow rates at 50% and the last 25% were measured. There was a significantly higher prevalence of almost all chronic respiratory symptoms in farmers compared with controls: highest among men for chronic cough (27.2%) and highest among women for dyspnea (28.3%). Typical symptoms of occupational asthma were diagnosed in 3.6% of the male and 1.5% of the female livestock farmers. A logistic regression analysis performed on chronic respiratory symptoms of livestock workers indicate significant effects of smoking (P < 0.001) on all symptoms except occupational asthma. A large number of male and female livestock farmworkers complained of acute work-related symptoms: highest for dry cough (52.2%) and shortness of breath (44.9%). Lung function data among these workers demonstrated a trend toward lower lung function in general. Multivariate analysis of lung function parameters indicate significant effects of length of employment and smoking in male and length of employment in female livestock farmworkers. The data suggest that employment in livestock farming may be associated in a dose-dependent manner with the development of acute and chronic respiratory symptoms and lung function changes.

Agricultural Workers' Diseases↗

PubMed2001

Respiratory findings in farmworkers.

This investigation was designed to study respiratory problems in farmworkers. To better define the consequences of this work environment on respiratory health, 814 farmworkers (738 male and 76 female) were studied. The mean age of the men in this study was 38 years, and the mean duration of their employment was 15 years. For women, the mean age was 44 years and the mean duration of their employment was 10 years. Of the men, 56.5% were regular smokers, and 23.7% of the women were regular smokers. A group of 635 control workers without significant exposure to air pollutants were matched by sex, age, employment, and smoking habit. The prevalence of chronic symptoms among male farmworkers was greater (P < 0.01) than among male control subjects for chronic cough (24.8% vs 11.4%), chronic phlegm (22.8% vs 9.1%), and chronic bronchitis (20.1% vs 7.4%). Among women farmworkers, a significant difference was noted with controls for chest tightness (farmworkers, 21.1%; control subjects, 0%; P < 0.001). There was a high prevalence of acute symptoms among male and female farmworkers. In particular, farmworkers complained of more frequent cough, eye irritation, dyspnea, and throat irritation than did control subjects. For respiratory symptoms in male and female farmworkers, odds ratios were generally significant for smoking, age, and duration of employment. Ventilatory capacity tests were significantly reduced for farmworkers compared with predicted values. Regression analysis of ventilatory capacity tests in male farmworkers as a percentage of predicted values demonstrated significant coefficients for employment and smoking. Our data suggest that farmworkers are exposed to noxious agents that cause respiratory symptoms and ventilatory capacity impairment.

Adult↗

PubMed2001

Developmental screening of children diagnosed with congenital heart defects.

Children with congenital heart disease (CHD) are more likely than normal children to have developmental delays. The development of 64 children with CHD less than 6 years old was screened with the Denver II. Thirty-five of the 64 children had CHD that required surgical or catheter intervention. These 35 children were significantly less likely than other children with CHD to be normal on developmental screening (46% vs 86%, respectively). Thirty-four percent of children with more severe CHD were referred for early intervention. As research shows the efficacy of early intervention, results indicate the need for early developmental evaluation of children with CHD of hemodynamic significance.

Analysis of Variance↗

PubMed2001

Attitudes towards information system security among physicians in Croatia.

To examine attitudes about information system security among Croatian physicians a cross-sectional study was performed on a representative sample of 800 Croatian physicians. An anonymous questionnaire comprising 21 questions was distributed and statistical analysis was performed using a chi-square test. A 76.2% response rate was obtained. The majority of respondents (85.8%) believe that information system security is a new area in their work. In general, physicians are not informed about European directives, conventions, recommendations, etc. Only a small number of physicians use personal computers at work (29%). Those physicians who have a personal computer use it mainly for administrative reasons. Most healthcare institutions (89%) do not have a security manual and the area of information system security is left to individual interest and initiative. Only 25% of physicians who have a personal computer use any type of password. A high percentage of physicians (22%) has never thought about the problem of personal data being used by organizations (e.g. police, banks) without legal background; a small, but still significant percentage of physicians (5.6%) has even agreed with such use. Results indicate that for the vast majority of physicians, information system security is a new area in their daily work, one which is left to individual interest and initiative. They are not familiar with the ethical, technical and legal backgrounds which have been defined for that area within the Council of Europe and the European Union. New aspects: This is the first study performed in Central and Eastern Europe dealing with information system security, performed on a representative nationwide sample of all the physicians.

Adult↗

PubMed2001

Genealogical structuring of a population.

The study observed population of 484 generation restrictive genealogies collected in four Croatian regions during 1970/71 within "The study of fat and carbohydrate metabolism indicators correlated with the occurrence of diabetes in animal fat and oil consuming population groups". The genealogies were collected on two islands (Brac and Hvar) and in two continental regions (Sinjska Krajina and Srijem). Genealogy Structure Index (GSI) was defined as quantitative indicator of genealogy structure. GSI was continuos variable which, by its extreme, describes vertical and horizontal type of genealogy structure, independently of the way genealogies were collected. Genealogy structure of surveyed population was described on the basis of participation of different genealogy types. Populations of the island Hvar and Brac showed to have horizontal genealogy type, continental population of Sinjska Krajina showed to have mixed type and continental population of Srijem showed to have vertical type of genealogy structure.

Adult↗