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Biomedical subjects

K Stehr

Publications and source records attributed to K Stehr.

At least 37 records · Page 2Linked to original sources
PubMed1995

Antimicrobial activity and biocompatibility of polyurethane and silicone catheters containing low concentrations of silver: a new perspective in prevention of polymer-associated foreign-body-infections.

In modern medicine, infection is one of the most serious complications of implanted plastic devices. The host is not able to overcome this special type of opportunistic infection despite having a normal immune response and a low virulence of most of the bacteria involved. Antimicrobial therapy alone generally cannot cure the infection and the removal of catheters often remains the only choice of therapy. Bacterial adhesion to the polymer surface of the catheter, be it luminal or external, is an important step in the pathogenesis of catheter-associated infections. In this report, we describe new approaches to the prevention of infections by impregnation of polyurethane and silicone with silver by two different methods. The antimicrobial activity of these silver-impregnated catheters is more than 10 fold higher for coagulase-negative staphylococci (CNS) compared to catheters without silver. Similar results are obtained with other microbial organisms like Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The new polymers show no cytotoxic or thrombogenic side effects in vitro.

Anti-Bacterial Agents↗
PubMed1995

Comparison of values of antibody to Bordetella pertussis antigens in young German and American men.

Pertussis is well controlled in the United States by routine childhood immunization. In contrast, this disease is endemic and epidemic in Germany because routine immunization has not been implemented. To gain information relating to the epidemiology of Bordetella pertussis infections, we examined the prevalence and magnitude of B. pertussis agglutinins and of IgG and IgA antibodies (detected by enzyme-linked immunosorbent assay) to four B. pertussis antigens--lymphocytosis-promoting factor, filamentous hemagglutinin, pertactin, and fimbriae-2--in the sera of 119 American university students and 119 German military recruits of similar age. Geometric mean titers of agglutinins and geometric mean values for IgG antibodies to the four antigens were two- to threefold higher in sera from the American students than in sera from German recruits. In contrast, the geometric mean IgA values and the percentage of subjects with detectable IgA antibodies to the four antigens were similar in the two populations. Since IgA antibody results mainly from infection and not from immunization, our data suggest that B. pertussis infections are common among both American and German young adults despite the marked difference in rates of clinical pertussis in the two countries.

Adult↗
PubMed1995

Pertussis in German adults.

In a large pertussis vaccine efficacy trial in Germany, vaccinees and/or their family members were seen if a cough illness of >14 days was reported. Evidence of recent Bordetella pertussis infection included a positive culture and/or polymerase chain reaction (PCR) and/or significant antibody values in agglutination and/or ELISA assay. From July 1991 through February 1994, 246 adults were evaluated and 64 had evidence of B. pertussis infection; of these, 38% had whooping, 26% had a history of previous pertussis, and 48% were the primary cases in a family. The 64 adult cases suggest an adult attack rate in this population of 133 per 100,000 population per year. Since pertussis has been endemic and epidemic in Germany during the last 2 decades, it would seem likely that few persons would escape B. pertussis infections during childhood. In this regard, none of the serological controls lacked antibody to all four B. pertussis antigens (lymphocytosis-promoting factor, filamentous hemagglutinin, pertactin, and fimbriae-2). Thus, serological evidence of past infection may not indicate protection, and the widely held belief that individuals who have had infections with B. pertussis have lifelong clinical immunity to this disease is probably wrong.

Adolescent↗
PubMed1995

Polymerase chain reaction identification of Bordetella pertussis infections in vaccinees and family members in a pertussis vaccine efficacy trial in Germany.

The polymerase chain reaction (PCR) was recently added to conventional culture and serology for the diagnoses of Bordetella pertussis infection in a large vaccine efficacy trial in Germany. In vaccinees or family members who had illnesses with cough, two nasopharyngeal swabs (calcium alginate for culture and Dacron for PCR) were taken and initial and follow-up clinical data were obtained. PCR was done using oligonucleotide primers PTp1 and PTp2 which amplify a 191-base pair DNA fragment of pertussis toxin operon. From December, 1993, to May, 1994, 555 pairs of swabs were processed; 28 grew B. pertussis and 9 grew B. parapertussis. Twenty-six of the 28 subjects with B. pertussis-positive cultures also had positive PCR results as did one of the 9 B. parapertussis cases and 82 additional samples were positive by PCR. PCR increased the identification of subjects with B. pertussis infections by almost 4-fold. Clinical characteristics were analyzed by laboratory category (Group 1, 28 culture-positive; Group 2, 82 culture-negative, PCR-positive; and Group 3, 436 culture- and PCR-negative). Group 1 subjects were more likely to have a diagnosis of definite or probable pertussis and to have paroxysmal cough, posttussive vomiting, whooping and a cough duration of > or = 4 weeks than Group 2 or 3 subjects. In contrast Group 2 subjects were more likely than Group 1 subjects to have had previous pertussis immunization or prior antibiotics. PCR identified many mild illnesses caused by B. pertussis that were not identified by culture.

Adult↗
PubMed1994

Clinical characteristics of illness caused by Bordetella parapertussis compared with illness caused by Bordetella pertussis.

In conjunction with a pertussis vaccine efficacy trial in Germany, nasopharyngeal specimens were collected from May, 1992, to March, 1993, from patients with cough illnesses. Clinical data were obtained by initial and follow-up questionnaires. Bordetella parapertussis was isolated from 38 patients (mean age, 3.5 years; 68% girls). Clinical characteristics in these cases were compared with those of 76 patients (matched by age and sex) with illness caused by Bordetella pertussis during the same period. Findings were: (B. pertussis/B. parapertussis): cough > 4 weeks 57%/37% (P = 0.06); whoop 80%/59% (P = 0.07); whoop > 2 weeks 26%/18% (P = 0.05); paroxysms 90%/83% (P = 0.5); body temperature > or = 38 degrees C 9%/0% (P = 0.17); vomiting 47%/42% (P = 0.69); and mean leukocyte and lymphocyte counts 12,500/mm3 and 7600/mm3 (P < 0.0001) and 7800/mm3 and 3500/mm3 (P < 0.0001), respectively. Illness caused by B. parapertussis was typical of pertussis but less severe than that caused by B. pertussis. In contrast with B. pertussis infection, lymphocytosis is not a characteristic of B. parapertussis infection. This is most likely a result of the lack of production of lymphocytosis-promoting factor toxin by B. parapertussis.

Bordetella↗
PubMed1994

The acute lymphoblastic leukaemia cell line SEM with t(4;11) chromosomal rearrangement is biphenotypic and responsive to interleukin-7.

A cell line, designated SEM, was established from the peripheral blood of a 5-year-old girl in relapse with acute lymphoblastic leukaemia (ALL). Both the lymphoblasts of the patient and the cells of the cell line SEM showed the t(4;11) chromosomal rearrangement. The analysis of the immunophenotype of the SEM cell line revealed the B-cell differentiation antigens CD19, CD22 and CDw75 in the absence of CD20, CD24 and immunoglobulin expression. Besides B-lineage antigens, SEM cells were positive for the myeloid antigens CD13, CD15, CD33 and CDw65. Immunogenotypic analysis of SEM cells showed a monoclonal rearrangement of immunoglobulin heavy-chain (IgH). T-cell receptor (TCR) gamma and delta genes. Addition of interleukin (IL)-7 promoted the growth of the patient's lymphoblasts in culture and enhanced the proliferation of SEM cells. The SEM cells also express messenger RNA (mRNA) for the IL-7 receptor (IL-7R), but no evidence for autocrine production of IL-7 by the cell line was found. Addition of IL-4, tumour necrosis factor (TNF)-alpha, interferon (IFN)-alpha, or IFN-gamma resulted in a profound inhibition of SEM growth. Thus, these cytokines may have important growth regulatory activities for biphenotypic leukaemic ALL cells.

Antigens, CD↗
PubMed1993

Brain abscesses in neonates--report of three cases.

We report three newborns with brain abscesses. Two infants suffered from Serratia marcescens meningitis and one infant had enterococcal sepsis and meningitis. Brain abscesses were detected by cerebral sonography. Outcome in one infant with S. marcescens infection was poor. This patient developed multicystic encephalo-malacia and severe developmental retardation. In the other patient with S. marcescens infection surgical drainage of the abscess was performed. The outcome was good both in this infant and in the patient with enterococcal brain abscess.

Brain Abscess↗
PubMed1993

Clinical and laboratory diagnosis of pertussis in the regions of a large vaccine efficacy trial in Germany.

As a support service for a pertussis vaccine efficacy trial, a central diagnostic laboratory was established. Physicians in the geographic areas of the planned study were encouraged to send nasopharyngeal specimens from children and household contacts with cough illnesses whether or not the illnesses were typical of pertussis. From April, 1991, to February, 1992, 3629 specimens were received and in 601 instances (16.6%) Bordetella pertussis was isolated. Only 3.3% of patients with positive cultures had received pertussis vaccine whereas 16.1% of culture-negative patients had received vaccine (P < 0.0001). Fever was more common (12.2%) in patients with negative cultures compared with those with positive cultures (5.4%) (P < 0.0001). B. pertussis isolation rates fell markedly after 21 days of cough. Significantly more patients with negative cultures compared with those with positive cultures had been treated with erythromycin (8.5 vs. 2.9%; P < 0.0001). Patients with cough for greater than 4 weeks and specimen collection within 2 weeks of cough onset had a B. pertussis isolation rate of 59%. Similarly if whoop occurred under the same circumstances the isolation rate was 80%. In this study 25.5% of patients with culture confirmed pertussis had illnesses with cough of less than 21 days duration. This finding suggests to us that a pertussis case definition in efficacy trials that requires cough of 21 days is excessively restrictive.

Adolescent↗
PubMed1993

[Tick bite and Lyme borreliosis. An epidemiologic study in the Erlangen area].

BACKGROUND: Lyme borreliosis is transmitted by tick bites. Approximately every fifth local tick (Ixodes ricinus) is infected. Transmission, therefore does not occur with every bite, and disease doesn't always follow infection. The goal of the study was to investigate the risks of infection and disease after tick bites in the area of Erlangen/Germany. METHODS: Between April 1989 and October 1991 seventy-one of our out-patients (30 females, 41 males) aged 6 months to 29 years had a tick bite and were enrolled into the study. After the ticks had been removed, a blood specimen for a specific Borrelia burgdorferi antibody assay (IFT) was collected. An interview by phone was performed 4 weeks later and an appointment for a second blood collection was arranged. RESULTS: In 69 patients the initial titer was negative, in two patients it was 1:32. Sixty patients could be reached by phone, and in 43 a second blood sample was available. There was seroconversion detectable in 4 instances, two of whom were asymptomatic, one had unspecific symptoms and one developed lymphocytoma. There were no manifestations of late stage disease in the study population. CONCLUSION: These results confirm the current recommendation of the Bundesgesundheitsamt (German Federal Health Institute) that generally antibiotic treatment after a tick bite is not necessary.

Adolescent↗
PubMed1992

Pulmonary artery sling associated with tracheobronchial malformations.

We describe three cases of pulmonary artery slings associated with tracheal stenoses by complete cartilaginous rings and abnormalities in the tracheobronchial branching pattern. This association implicates special problems of management that are different from the simple pulmonary artery sling. Pathologic anatomy, symptoms, diagnostic procedures, and the problems of therapy are described. Considering similar cases in the literature, we conclude that thorough diagnostic evaluation of the tracheobronchial and the cardial system should be carried out in all cases of pulmonary artery sling. Simple correction of the aberrant vessel without correcting the tracheal stenosis is of no value in these cases. In some milder cases, a conservative approach is possible and probably less harmful than an operation.

Abnormalities, Multiple↗
PubMed1992

Serious pertussis overlooked in infants.

Two infants with life-threatening pertussis are presented in whom the diagnosis was delayed. A review of pertinent literature suggests that the diagnosis of pertussis in infants is frequently missed and therefore the morbidity and mortality from this disease is underestimated.

Diagnostic Errors↗
PubMed1992

[Pertussis--an illness with typical clinical symptoms?].

There has been a noticeable increase in the incidence of pertussis in West Germany over the last decade. Since the availability of adequate bacteriological diagnosis a much broader clinical spectrum can be attributed to infections with B. pertussis. Three patients with an unusual clinical presentation of pertussis are presented. A three month old infant presented with severe apneic spells without cough as the sole clinical symptoms of the infection. B. pertussis was isolated in the nasopharyngeal swab. A nine month old premature infant with bronchopulmonary dysplasia after long time intubation and artificial ventilation presented with apneic spells, pulmonary and cardiac decompensation and required ventilatory support. The diagnosis was suggested by a massive leucocytosis with lymphocytosis. The diagnosis on the patient was established by serologic methods. Adult contacts of this patient developed longstanding cough and clinical signs of pertussis. The diagnosis of pertussis in these persons was established by nasopharyngeal culture. The third patient with trisomy 21 and a corrected AV canal suffered from nonspecific cough and gradually developed signs of congestive heart failure with pneumonia. B. pertussis was isolated from the nasopharynx. This patient showed neither the typical paroxysmal coughing spells nor disclosed the typical lymphocytosis in his white blood count. Microbiological investigations of patients with symptoms of respiratory tract infections should include the isolation of B. pertussis. Thus, additional cases of pertussis not suspected on the basis of their initial clinical presentation will be detected.

Administration, Oral↗
PubMed1991

[Single incisor syndrome and growth hormone deficiency].

The syndrome of single incisor belongs to the group of midline malformations and is characterized by a single incisor in the patient's maxilla. A growth hormone deficiency (GHD) can be associated. We report about two of our patients with this syndrome. A GHD was diagnosed at the age of 11.0 and 7.6 years, respectively, although a single incisor had already been present during their first dentition. The first patient was treated with HGH to a chronological age of 18.6 years (final height 168 cm), the second patient is still on therapy. The growth of children with craniofacial dysmorphic features must be controlled closely in order to diagnose a GHD in time.

Child↗
PubMed1990

[Haemophilus influenzae type B. Disease and prevention].

Haemophilus influenzae is a gram-negative rod, causing severe infections in childhood, including meningitis, sepsis, epiglottits, pneumonia and otitis. Most of the invasive infections are due to serotype b. Since ampicillin-resistance is increasing, modern cephalosporines like cefotaxime and ceftriaxone are the antibiotics of choice in severe disease. Bacterial meningitis due to Haemophilus influenzae and epiglottitis are both still life-threatening diseases with a lethality of 5% to 25%, and there are severe sequelae in 35% of meningitis cases. Efforts have been made to develop efficacious vaccines. While immunogenicity of type b polysaccharide was low in the high-risk age (below 18 months), conjugated vaccines with either diphtheria-toxoid or Neisseria meningitis outer membrane protein and the Hib polysaccharide were found to be strongly immunogenic even in the first months of life. These vaccines show every few side-effects and can easily be combined with other immunizations such as DPT and DT. Thus, the incidence of invasive infections due to Haemophilus influenzae type b might decline in future.

Anti-Bacterial Agents↗
PubMed1989

[Effect of obstetric-perinatal measures on mortality and early morbidity of premature infants weighing 500 to 1,500 grams].

In a retrospective analysis of perinatal influencing factors in 186 premature newborns of the Department of Gynaecology of the University of Erlangen covering the period from 1982-1987 with birth weights between 500 and 1500 grams, the mortality and early morbidity were analysed, as characterised by cerebral haemorrhages, respiratory distress syndrome and infections insofar, as they had been connected with the obstetrical approach and paediatric intensive-care treatment, 45 infants born in 1982/83 were compared with 141 infants, who had been subjected to a different treatment approach during 1984 to 1987. During the second period, there was a marked drop both in mortality and in the incidence of asphyxia-induced severe cerebral haemorrhage and of the respiratory distress syndrome. A shortened latency period after premature rupture of the amnion, and a more pronounced presence of a neonatologically experienced team of paediatricians were found to be significant obstetric liberal influencing factors in determining the need to perform Caesarean section. The triplication of the frequency of Caesarean section observed resulted in a 50% reduction in perinatal mortality and morbidity. Infants with pelvic presentation benefited most from the more liberal performance of Caesarean section, as did infants with vertex presentation. Shortening of the latency phase in premature rupture resulted in a marked reduction in infection morbidity and mortality. Therefore we conclude, that the frequently practised procrastination with the aim to await an improvement in lung maturity should be replaced by a more active obstetric management, avoiding both infection and birth trauma. Obstetric decisions should be based rather on prenatal estimation of weight than on the calculated gestational age. At present, the lowest birth weight associated with the expectation of a healthy life is considered to be 750 grams.

Asphyxia Neonatorum↗
PubMed1989

High-molecular-mass ("biliary") isoenzyme of alkaline phosphatase and the diagnosis of liver dysfunction in cystic fibrosis.

The high-Mr isoenzyme of alkaline phosphatase (AP, EC 3.1.3.1), a highly sensitive index to cholestasis, was measured by liquid chromatography in 45 patients with cystic fibrosis. Results of serum tests for liver dysfunction--including gamma-glutamyltransferase, aspartate aminotransferase, alanine aminotransferase, total AP, bilirubin, and bile acids--were compared with those for high-Mr AP. Values for high-Mr AP were increased in 44.4% of our patient population, with activities ranging from 0.4 to 17.3 U/L. The upper limit in the control group was 2.5 U/L. We find increased high-Mr AP to be a more sensitive indicator of liver dysfunction in patients with cystic fibrosis than are other tests.

Adolescent↗
PubMed1988

High-molecular-mass alkaline phosphatase: simplified and highly sensitive determination by liquid chromatography.

This simplified HPLC method for measurement of high-molecular-mass alkaline phosphatase (high-Mr AP; EC 3.1.3.1) in serum and bile is rapid (time for column preparation and separation 30 min), reproducible (CV 4.2%), and highly sensitive (detects high-Mr AP in healthy controls at 1-3% of total AP activity in serum), and is suitable for processing small batches of sample. We characterized high-Mr AP in serum and bile by incubating samples with L-phenylalanine, neuraminidase, 1-butanol, or wheat-germ lectin, and by determining stability to heat. High-Mr AP activity was determined in sera of patients with various liver diseases (4-32% of total AP serum activity) and results were compared with those by electrophoresis on agarose.

Alkaline Phosphatase↗