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Biomedical subjects

G Petersen

Publications and source records attributed to G Petersen.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of respiratory syncytial virus detection by rapid antigen tests in childhood.

BACKGROUND: Rapid and reliable diagnosis is crucial for clinical management of respiratory syncytial virus infection in childhood. We assessed the performance characteristics of respiratory syncytial virus antigen immunoassays in children hospitalized for respiratory infection. METHOD: A total of 1600 children up to three years of age hospitalized for diseases potentially caused by RSV were included in the study. Nasopharyngeal secretions were obtained in a standardized manner in the first 24 hours after hospital admission and tested in parallel by PCR and rapid antigen tests for RSV. The following parameters were recorded: recruitment center, gender, age, presence of fever, rhinitis, stridor, barking cough, cough, wheezing, vomiting, disturbed eating or sleep, tachypnea, tachycardia, increased body temperature, decreased oxygen saturation, C-reactive protein, erythrocyte sedimentation rate and chest X-ray results. RESULTS: Considering PCR testing as gold standard, rapid antigen testing had a specificity of 89.9% and a sensitivity of 66.2% for all samples tested. Logistic regression analysis revealed age and recruitment center as the only parameters influencing sensitivity whereas no such influence on specificity was found. Positive likelihood ratios ranged from 4,9 to 6.9 in different age groups. Negative likelihood ratio was 0.24 (95% CI: 0.18-0.42) in children aged up to 3 months but 0.67 (95% CI: 0.53-0.84) for children older than 2 years. CONCLUSION: Rapid detection of RSV antigen in this study was useful in detection of RSV mediated disease in younger infants but shows decreasing sensitivity in children older than three months.

Antigens, Viral↗
PubMed2006

Immunogenicity, reactogenicity and safety of a 7-valent pneumococcal conjugate vaccine (PCV7) concurrently administered with a DTPa-HBV-IPV/Hib combination vaccine in healthy infants.

BACKGROUND: To evaluate immunogenicity, reactogenicity, and safety of a hexavalent combination vaccine diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio virus-Haemophilus influenzae type b (DTPa-HBV-IPV/Hib) when coadministered with a 7-valent pneumococcal conjugate vaccine (PCV7). METHODS: Infants received either a hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio virus-H. influenzae type b vaccine concomitantly with PCV7 or DTPa-HBV-IPV/Hib alone infants were vaccinated at 2, 3 and 4 months (primary immunization) and 12-15 months of age (booster dose). Local and systemic reactions and adverse events were monitored following each dose and compared between groups. Blood was obtained prior to dose 1, one month after dose 3, immediately prior to and 1 month following the booster dose to measure antibody responses to each of the antigens. RESULTS: Two hundred and fifty-three subjects (PCV7, 127; Control, 126) were enrolled. Antibody responses were compared in 226 subjects for the primary immunization and 212 for the booster dose (per-protocol (PP) population). Although there were some differences in geometric mean concentrations (GMCs) to the DTPa-HBV-IPV/Hib antigens after the primary series, GMCs for all antigens after the booster dose were similar in both groups, except for diphtheria which was significantly higher in the PCV7 group (PCV7, 7.41 IU/mL; Control, 5.78 IU/mL). Reactogenicity and safety data were compared in 252 infants receiving primary immunization and 235 children receiving the booster dose. Site reactions were similar in both groups. Fever >or=38.0 degrees C following each vaccination was reported more frequently in the PCV7 group (28.3-50.0%) than in the Control group (15.6-33.6%) whereas fever >39.0 degrees C occurred only in a few cases and to the same extent in both groups (PCV7, 0.8-2.7%; Control, 1.6-4.1%). Only one reported serious adverse event was characterized as being related to the study vaccines: control subject was hospitalized with a fever. CONCLUSION: DTPa-HBV-IPV/Hib and PCV7 were highly immunogenic, well-tolerated and safe when coadministered at 2, 3 and 4 months of age with a booster dose at 12-15 months of age. These results support the coadministration of PVC7 with DTPa-HBV-IPV/Hib as part of the routine immunization schedule for infants and children.

Antibody Formation↗
PubMed2006

Hydrolysis and fermentation of activated sludge to enhance biological phosphorus removal.

The conventional mainstream enhanced biological phosphorus removal (EBPR) process depends on the quality of the raw incoming wastewater. An alternative sidestream EBPR process is presented, where the substrates for storage by the polyphosphate accumulating organisms (PAOs) instead come from hydrolysis of the return activated sludge. This process is studied in full-scale at two treatment plants and quantified by means of phosphorus release rates and readily biodegradable COD (RBCOD) accumulation rates. It was seen that not only was a significant amount of RBCOD stored by PAOs but an approximately equal amount was accumulated in the sidestream hydrolysis tank and made available for the subsequent nitrogen removal process. The phosphorus release of the sludge with and without addition of different substrates was furthermore studied in laboratory scale. The study showed that the process is promising and in a number of cases will have significant advantages compared with the conventional mainstream EBPR

Denmark↗
PubMed2004

Determination of the population size in an epidemiological study with children.

OBJECTIVES: To obtain a reliable estimate of the population size in an epidemiological study concerned with incidence estimation. METHODS: In the present case, the population of interest consists of all children attending a certain pediatric practice for any reason and is estimated making use of the number of regularly attended well baby visits. In some cases, exact figures from the practices are available as a reference. A prospective epidemiological study on the estimation of the incidence of lower respiratory tract infections (LRTI) in the German pediatric population (PRI.DE, Parainfluenza- und Respiratory-Syncytial-Virus-Infektionen in Deutschland) is used to demonstrate the procedure. RESULTS: In most cases, the fit can be regarded as good with deviations between 11% and 17%, whereas in a few cases it must be considered as poor (deviations of 60%). CONCLUSIONS: The importance of using exact figures whenever obtainable and of appraising the results carefully is emphasized.

Child Health Services↗
PubMed2002

Prospective population-based study on rotavirus disease in Germany.

UNLABELLED: The aim of this study was to collect representative data on the incidence and clinical characteristics of community-acquired acute gastroenteritis (AGE) due to rotavirus (RV) in German children up to 4 y of age. In 20 paediatric practices in 5 German regions every child aged 0-4 y presenting with symptoms of AGE from May 1997 to April 1998 was eligible for inclusion into the study. Stool samples were tested for RV antigen by enzyme-linked immunosorbent assay and polymerase chain reaction was performed for serotyping. The course of the disease, additional diagnoses and treatment regimen were recorded. Incidences adjusted for month and region of observation were calculated by Poisson regression. Of 15,451 children under observation 3980 (26%) presented with AGE. Of 3156 stool samples available 748 (24%) proved RV positive. The incidence of AGE and RV-positive AGE was 25.2 and 4.0 per 100 children per year, respectively, with a maximum in February/March 1998. RV-positive cases were more severe than RV-negative cases (28% vs 12% severe cases, hospitalization rate 6.2% vs 2.0%, p < 0.001). The predominant genotype of RV isolated was G1/P[8] (77%), followed by G4/P[8] (17%). CONCLUSION: Rotavirus accounts for a substantial part of severe cases of AGE in children up to 4 y of age. Efficient prevention, including immunization against the circulating serotypes, could save at least 122,000 children in Germany from falling ill with RV-AGE each year.

Child, Preschool↗
PubMed2002

Typical features of cerebellar ataxic gait.

BACKGROUND: Although gait disturbance is one of the most pronounced and disabling symptoms in cerebellar disease (CD), quantitative studies on this topic are rare. OBJECTIVES: To characterise the typical clinical features of cerebellar gait and to analyse ataxia quantitatively. METHODS: Twelve patients with various cerebellar disorders were compared with 12 age matched controls. Gait was analysed on a motor driven treadmill using a three dimensional system. A tandem gait paradigm was used to quantify gait ataxia. RESULTS: For normal locomotion, a significantly reduced step frequency with a prolonged stance and double limb support duration was found in patients with CD. All gait measurements were highly variable in CD. Most importantly, balance related gait variables such as step width and foot rotation angles were increased in CD, indicating the need for stability during locomotion. The tandem gait paradigm showed typical features of cerebellar ataxia such as dysmetria, hypometria, hypermetria, and inappropriate timing of foot placement. CONCLUSIONS: Typical features of gait in CD are reduced cadence with increased balance related variables and an almost normal range of motion (with increased variability) in the joints of the lower extremity. The tandem gait paradigm accentuates all the features of gait ataxia and is the most sensitive clinical test.

Disability Evaluation↗
PubMed2002

Effect of two oral contraceptives containing ethinylestradiol and levonorgestrel on serum and urinary surrogate markers of endothelial function.

OBJECTIVE: To investigate the effect of two oral contraceptives containing 0.02 mg ethinylestradiol and 0.1 mg levonorgestrel (Formulation A, Leios), and the other containing 0.03 mg ethinylestradiol and 0.15 mg levonorgestrel (Formulation B, Stediril 30) on the serum and urinary concentrations of various markers reflecting the status of vascular tone and development of atherosclerosis. The adhesion molecules E-selectin, inter-cellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and homocysteine were included as serum markers and cGMP, prostacyclin and its antagonist thromboxane as urinary markers. METHODS: In a comparative, double-blind, randomized, parallel group study, 34 women received formulation A and 33 women formulation B. Serum samples were collected before treatment and after 3, 6 and 12 cycles. Nocturnal urine was collected before treatment and during cyclic treatment after 3 and 12 cycles. Serum and urinary markers were measured by enzyme immunoassays. RESULTS: E-selectin levels were significantly reduced by both contraceptives after 3, 6 and 12 months compared to pretreatment levels. A slight increase in ICAM concentrations was observed for both contraceptives after 6 cycles, but this fell to pretreatment levels after 12 cycles. VCAM values were significantly lowered after 3, 6 and 12 months by both contraceptives. No significant changes were found in serum levels of homocysteine. No significant differences were found between treatment groups for the serum markers. Both contraceptives significantly enhanced urinary cGMP excretion after 12 cycles. The prostacyclin metabolite remained unchanged in the case of both formulations, but the excretion of the thromboxane metabolite was significantly decreased after 12 cycles. Thus, the ratio of prostacyclin to thromboxane, decisive for the resulting effect on vascular tone, increased significantly. CONCLUSION: These results indicate that the low-dose oral contraceptives can reduce the production of adhesion molecules which play a crucial role in the early stages of atherosclerosis. In addition, these contraceptives can shift the balance of vascular tone towards dominance of vasodilatory substances after 12 cycles of treatment. Thus, the positive influence of these contraceptives on the various markers investigated may improve vascular tone and impede development of atherosclerosis.

Adult↗
PubMed2001

Effect of two oral contraceptives with different ethinyl estradiol and levonorgestrel concentrations on the urinary excretion of biochemical vasoactive markers.

In the present study the effect on the urinary excretion of vasoactive markers of two oral contraceptives (OCs), i.e., Leios, containing 0.02 mg ethinyl estradiol and 0.1 mg levonorgestrel, and Stediril 30, containing 0.03 mg ethinyl estradiol and 0.15 mg levonorgestrel, was investigated. cGMP, prostacyclin and its antagonist thromboxane, serotonin, and urodilatin, a natriuretic and diuretic peptide formed in the kidney, were measured as markers. In a comparative, double-blind, randomized, parallel group study, 34 women received Leios and 33 women Stediril 30. Nocturnal urine was collected before treatment and during cyclic treatment after 3 and 12 cycles. Both contraceptives significantly enhanced cGMP excretion after 12 cycles. The prostacyclin metabolite remained unchanged for both formulations, but the excretion of the thromboxane metabolite was significantly decreased after 12 cycles. Thus, the ratio of prostacyclin to thromboxane, crucial for the resulting effect on vascular tone, increased significantly. For the serotonin metabolite, no changes were observed for both contraceptives. The excretion of urodilatin significantly increased for both preparations after 12 cycles compared to the pretreatment values. These results indicate that the low-dose OCs Leios and Stediril 30 may stimulate the production of some vasoactive markers, at least after 12 cycles of treatment. The positive influence of these contraceptives on the various markers investigated may improve vascular tone, impede development of atherosclerosis and arterial thrombosis, and improve water and electrolyte homeostasis. These effects most likely can be attributed to the estrogenic component. Levonorgestrel may elicit no impact on these estrogen-induced changes that, however, seem only to be manifested after a longer treatment period.

Adult↗
PubMed2001

The gait disorder of advanced essential tremor.

Gait disturbances of patients with essential tremor (ET) have been described anecdotally, but have never been investigated quantitatively. Recent studies provided evidence for a cerebellar-like hand tremor in some patients with ET. Therefore, we designed a study to assess cerebellar-like abnormalities of leg function. Twenty-five patients with ET, eight patients with cerebellar diseases (CD) and 21 age-matched healthy subjects were studied for their normal and tandem gait using a three-dimensional gait analysis system. During normal walking, CD and ET patients showed only slight abnormalities. However, ET patients exhibited abnormalities in tandem gait with an increased number of mis-steps and a broad-based, ataxic and dysmetric gait which was indistinguishable from the findings in CD. When ET patients were separated into groups of those with or without intention tremor of the hands, the gait disorder was found to be much more pronounced in the intention tremor group. Patients with this gait disorder were more severely disturbed in their activities of daily living, and suffer from an advanced stage of ET. The present results quantitatively describe a gait disturbance in advanced ET which affects tandem gait, but leaves normal gait almost unaffected. This is strong evidence for a cerebellar-like disturbance in ET.

Adult↗
PubMed2001

International variation in disease burden of rotavirus gastroenteritis in children with community- and nosocomially acquired infection.

BACKGROUND: The great impact of rotavirus disease on morbidity and medical health care costs in industrialized countries together with the withdrawal of the live oral rotavirus vaccine have made a reassessment of rotavirus gastroenteritis necessary. Such a reassessment should provide sufficient data for developing alternative disease prevention strategies and for allocating resources efficiently. OBJECTIVES: To compare characteristics and management of community- and nosocomially acquired rotavirus disease in Austria, Germany and Switzerland. PATIENTS AND METHODS: In a prospective, population-based, trinational (Austria, Germany, Switzerland), multicenter (9 cities, 10 hospitals and 30 pediatric practices) study, a total of 174 552 children months and 78 516 hospital days were evaluated. Participants were all children 4 years of age and younger, who either presented at one of the pediatric practices with community-acquired gastroenteritis, or who had acquired gastroenteritis nosocomially. From December, 1997, to May, 1998, prospective antigen testing was done by enzyme-linked immunosorbent assay, and serotyping was done by reverse transcription polymerase chain reaction. Disease severity was scored by the Vesikari severity scale. RESULTS: Rotavirus was detected in 29.5, 27 and 37.5% of children with community-acquired gastroenteritis and in 57, 69 and 49% of children with nosocomial gastroenteritis in Austria, Germany and Switzerland, respectively. Severity of community-acquired rotavirus gastroenteritis was more pronounced in Austria (median severity score, 11) than in Germany (median score, 9) or Switzerland (median score, 10). However, only 2% of Austrian and Swiss children compared with 12% of German children presented to their pediatricians more than four times. Nosocomially acquired rotavirus gastroenteritis was mildest in Austria but occurred within the shortest median duration of hospitalization (4 days vs. 5 and 7 in Germany and Switzerland, respectively). In a multivariant analysis age, family size, day care, breast-feeding and nationality were not predictive factors for enhanced risk to contract rotavirus infection. Alimentation was changed frequently; diet was used between 23 and 83%; special formulas were used between 10 and 57%. CONCLUSION: The cumulative experience from three European countries suggest that rotavirus is an important cause of diarrhea in Central Europe, but significant local differences clearly demonstrate the need for obtaining national data as a reliable basis for control and prevention of the disease.

Child, Preschool↗
PubMed2000

Dissection of the ATP-binding domain of the chaperone hsc70 for interaction with the cofactor Hap46.

Several unrelated proteins are known that specifically interact with members of the mammalian hsp70 chaperone protein family independent of the hsp70 substrate-binding site. One of these is Hap46, also called BAG-1, which binds to the ATP-binding domain of hsp70 and its constitutively expressed, highly homologous counterpart hsc70, thereby affecting nucleotide binding, as well as protein folding properties, of these molecular chaperones. In an attempt to delineate the potential contact sites on hsp70/hsc70 involved in this interaction we made use of the following two independent approaches: (i) screening of membrane-bound peptide libraries based on the sequence of the ATP-binding domain and (ii) the phage-display technique with random dodecapeptides. These approaches yielded partially overlapping results and identified several possible contact regions. On the space-filling model of hsc70, the two major contact areas for Hap46 delineated in the present study are located on the same side of the molecule on either subdomain that border the central cleft harboring the nucleotide-binding site. We suggest that this bridging affects the conformation of the ATP-binding domain in a way similar to the opening of the nucleotide-binding cleft produced in the bacterial hsp70 homologue DnaK upon binding its regulatory protein GrpE.

Adenosine Triphosphate↗
PubMed2000

N-Acylethanolamines and precursor phospholipids - relation to cell injury.

The present review focuses on the relationship between formation of N-acylethanolamine phospholipids (NAPEs) and N-acyletransferase (NAEs) catalyzed by N-acyltranferase and NAPE-hydrolyzing phospholipase D, respectively, and cell injury in tissues like brain, heart, and testis. A number of mechanisms are proposed by which these two groups of lipids may have cytoprotective properties. The mechanisms may involve activation of cannabinoid receptors, as well as non-receptor-mediated effects such as stabilization of membrane bilayers, antioxidant mechanisms, inhibition of calcium leakage from mitochondria, and direct inhibition of ceramidase. Anandamide (20:4-NAE) is formed as a minor component along with other NAEs during cell injury. Whether 20:4-NAE has a separate physiological role is at present not known, but some data suggest that 20:4-NAE may be formed, e.g. in the uterus, by a more selective mechanism without being accompanied by a vast majority of saturated and monounsaturated NAEs.

Animals↗
PubMed2000

Population carrier frequency of hMSH2 and hMLH1 mutations.

Knowledge of population carrier frequency for DNA mismatch repair (MMR) gene mutations would contribute to understanding the burden of cancer due to genetic susceptibility, but robust prevalence estimates are lacking. To estimate carrier frequency, we genotyped a cohort of relatives of mutation carriers and determined their colorectal cancer prevalence. Systematic Finnish and US data were combined with Scottish genotype and cancer prevalence data in a Bayesian calculation. The estimated carrier prevalence in the population aged 15-74 years is 1:3139 (95% Cl = 1:1247-1:7626) and these carriers are at high risk of colorectal and other cancers.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Phylogenetic evidence for excision of Stowaway miniature inverted-repeat transposable elements in triticeae (Poaceae).

The mode of transposition of miniature inverted-repeat transposable elements (MITEs) is unknown, but it has been suggested that they are duplicated rather than excised at transposition. However, the present investigation demonstrates that a particular family of MITEs, Stowaway:, is excised. Mapped onto a gene tree based on partial sequences of disrupted meiotic cDNA1 (DMC1) from 30 species of the Triticeae grasses, it is evident that at least two excisions have occurred, leaving short footprints. These footprints may subsequently be reduced in length or deleted. Excision of Stowaway: elements lends strong support to the suggestion that MITEs are DNA transposons and should be classified as class II elements. The evolution of Stowaway: elements can also be traced by scrutiny of the gene tree. It appears that base substitutions are as frequent in the conserved terminal inverted repeats (TIRs) as in the core of the element. Neither substitutions nor deletions lead to compensatory changes; hence, the highly stable secondary structure of the elements may gradually be reduced.

Base Sequence↗
PubMed2000

Monoclonal antibodies against the adeno-associated virus type 2 (AAV-2) capsid: epitope mapping and identification of capsid domains involved in AAV-2-cell interaction and neutralization of AAV-2 infection.

The previously characterized monoclonal antibodies (MAbs) A1, A69, B1, and A20 are directed against assembled or nonassembled adeno-associated virus type 2 (AAV-2) capsid proteins (A. Wistuba, A. Kern, S. Weger, D. Grimm, and J. A. Kleinschmidt, J. Virol. 71:1341-1352, 1997). Here we describe the linear epitopes of A1, A69, and B1 which reside in VP1, VP2, and VP3, respectively, using gene fragment phage display library, peptide scan, and peptide competition experiments. In addition, MAbs A20, C24-B, C37-B, and D3 directed against conformational epitopes on AAV-2 capsids were characterized. Epitope sequences on the capsid surface were identified by enzyme-linked immunoabsorbent assay using AAV-2 mutants and AAV serotypes, peptide scan, and peptide competition experiments. A20 neutralizes infection following receptor attachment by binding an epitope formed during AAV-2 capsid assembly. The newly isolated antibodies C24-B and C37-B inhibit AAV-2 binding to cells, probably by recognizing a loop region involved in binding of AAV-2 to the cellular receptor. In contrast, binding of D3 to a loop near the predicted threefold spike does not neutralize AAV-2 infection. The identified antigenic regions on the AAV-2 capsid surface are discussed with respect to their possible roles in different steps of the viral life cycle.

Amino Acid Sequence↗
PubMed2000

Age dependent accumulation of N-acyl-ethanolamine phospholipids in ischemic rat brain. A (31)P NMR and enzyme activity study.

N-acyl-ethanolamine phospholipids (NAPE) can be formed as a stress response during neuronal injury, and they are precursors for N-acyl-ethanolamines (NAE), some of which are endocannabinoids. The levels of NAPE accumulated during post-decapitative ischemia (6 h at 37 degrees C) were studied in rat brains of various age (1, 6, 12, 19, 30, and approximately 70 days) by the use of (31)P NMR spectroscopy of lipid extracts. This ability to accumulate NAPE was compared with the activity of N-acyltransferase and of NAPE-hydrolyzing phospholipase D (NAPE-PLD) in brain microsomes. These two enzymes are involved in the formation and degradation of NAPE, respectively. The results showed that 1) the ability to accumulate NAPE during post-decapitative ischemia is especially high in the youngest rats and is markedly reduced in older brains [in 1-day-old rat brains NAPE accumulated to 1.5% of total phospholipids, while in 30-day-old rat brains NAPE accumulation could not be detected (detection limit 0.09%)] and 2) this age pattern of accumulation can be explained by a combination of the decreased activity of N-acyltransferase and the increased activity of NAPE-PLD during development. These results point out that it would be advantageous to investigate a potential cytoprotective role of NAPE in the brains of very young rats.

Acyltransferases↗