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Biomedical subjects

G Koch

Publications and source records attributed to G Koch.

At least 19 recordsLinked to original sources
PubMed2006

Outbreak of avian influenza H7N3 on a turkey farm in the Netherlands.

This case report describes the course of an outbreak of avian influenza on a Dutch turkey farm. When clinical signs were observed their cause remained unclear. However, serum samples taken for the monitoring campaign launched during the epidemic of highly pathogenic avian influenza in 2003, showed that all the remaining turkeys were seropositive against an H7 strain of avian influenza virus, and the virus was subsequently isolated from stored carcases. The results of a reverse-transcriptase pcr showed that a H7N3 strain was involved, and it was characterised as of low pathogenicity. However, its intravenous pathogenicity index was 2.4, characterising it as of high pathogenicity, suggesting that a mixture of strains of low and high pathogenicity may have been present in the isolate. The outbreak remained limited to three farms.

Animals↗
PubMed2006

[Uncommon diagnosis in a patient with fever and new-onset cardiac murmur].

HISTORY AND PHYSICAL FINDINGS: A 34-year old man was referred because of persistent low-grade fever and a newly-diagnosed systolic murmur. He complained of atypical chest pain and dyspnoea on exertion for the past few weeks. STUDIES: Blood analysis revealed an elevated CRP level (67.7 mg/l) along with a hypochromic, microcytic anaemia (Hb 122 g/l). Transthoracic echocardiography showed an extracardiac tumour compressing the right ventricular outflow tract. Computed tomography (CT) localized the tumour in the anterior upper mediastinum. Subsequently, a biopsy was carried out and revealed a non-seminomatous germ-cell tumour. DIAGNOSIS, TREATMENT AND COURSE: The diagnosis having been made the patient received four cycles of chemotherapy according to the BEP-protocol (bleomycin-etoposide-cisplatin). The remaining tumour was then resected surgically. After additional cycles of chemotherapy two autologous stem cell transplantations were carried out. CONCLUSION: This patient presented initially with symptoms typical of endocarditis. However, the reason for his newly diagnosed systolic murmur and persistent fever was an extracardiac germ cell tumor compressing the right ventricular outflow tract.

Adult↗
PubMed2006

Muscle force and fatigue in patients with sepsis and multiorgan failure.

INTRODUCTION: Neuromuscular abnormalities are found frequently in sepsis and multiorgan failure (MOF). Surprisingly, however, there are no data on maximum skeletal muscle force and fatigue in these patients. OBJECTIVES: To test the research hypotheses that adductor pollicis (AP) force would be lower in patients with sepsis, whereas fatigue would not differ between patients and immobilized but not infected volunteers. DESIGN AND SETTING: Prospective study; university intensive care unit and laboratory. PATIENTS: Patients with sepsis and MOF (sequential organ failure assessment (SOFA) score >10) and healthy volunteers. INTERVENTIONS: Fatigue was evoked during 20[Symbol: see text]min of intermittent tetanic ulnar nerve stimulation achieving 50% of maximum AP muscle force. MEASUREMENTS AND RESULTS: We measured evoked AP muscle force and fatigue, and compound muscle action potential (CMAP), and performed standard electrophysiological tests in 13 patients, and in 7 volunteers before and after immobilization. Maximum force (20+/-16 vs 65+/-19N; p<0.01) and CMAP (3.6+/-2.5 vs 10+/-2.5 mV; p<0.05) were markedly decreased in patients; however, fatigue and ulnar nerve conduction velocity did not differ from volunteers, and a decrement of CMAP was not observed with nerve stimulation frequencies up to 40 Hz. All patients with critical illness polyneuropathy, and an additional 50% of those without, had significant muscle weakness. CONCLUSION: Peripheral muscle force is markedly decreased in sepsis, without evidence for an increased fatigability. Muscle weakness was most likely due to a sepsis-induced myopathy and/or axonal neuropathy, and was not the result of an immobilization atrophy.

Action Potentials↗
PubMed2006

A survey of specialist paediatric dental services in Sweden: results from 2003, and trends since 1983.

UNLABELLED: The child population in Sweden has changed dramatically during the last 20 years. Changes have also occurred within the Public Dental Service (PDS), regarding the provision of dental care to children and adolescents. All these changes may affect the referral pattern and provision of specialist dental care for children and adolescents. OBJECTIVES: The primary aim of this study was to survey the services provided by specialists in paediatric dentistry in Sweden during 2003. A secondary aim was to compare the results with previous surveys. METHODS: A Web-based survey was sent to all 34 specialist paediatric dentistry clinics and was answered by all clinics. Data were compared with results from the surveys performed in 1983, 1989, and 1996. RESULTS: The number of paediatric dentists had been relatively constant over the last 20 years, whereas the number of children referred to paediatric dentists had increased by 28% since 1983. It was estimated that 1.3% of all children in Sweden are treated at a specialist paediatric dental clinic in 2003. Dental treatment need in combination with behaviour management problems (BMP) was the main reason for referral and occurred in 37% of all referrals. The proportion of medically compromised children/children with disabilities had increased from 6% in 1983 to 22% in 2003. The number of patients treated using sedation and general anaesthesia had increased since 1983, and particularly since 1996. CONCLUSIONS: Despite improvements in dental health among children and adolescents in Sweden during the last 20 years, an increasing number of children are referred for specialist paediatric dental treatment. There is an urgent need to increase the number of specialist paediatric dentists in Sweden in order to ensure the continuation of high quality of dental care for children and adolescents.

Adolescent↗
PubMed2005

Topochemical studies on modified lignin distribution in the xylem of Poplar (Populus spp.) after wounding.

BACKGROUND AND AIMS: Information on the influence of wounding on lignin synthesis and distribution in differentiating xylem tissue is still scarce. The present paper provides information on cell modifications with regard to wall ultrastructure and lignin distribution on cellular and subcellular levels in poplar after wounding. METHODS: Xylem of Populus spp. close to a wound was collected and processed for light microscopy, transmission electron microscopy and cellular UV microspectrophotometry. Cell wall modification with respect to lignin distribution was examined at different stages of wound tissue development. Scanning UV microspectrophotometry and point measurements were used to determine the lignin distribution. KEY RESULTS: Xylem fibres within a transition zone between differentiated xylem laid down prior to wounding and the tissues formed after wounding developed distinctively thickened secondary cell walls. Those modified walls and cell corners showed, on average, a higher lignin content and an inhomogeneous lignin distribution within the individual wall layers. CONCLUSIONS: The work presented shows that wounding of the xylem may induce a modified wall architecture and lignin distribution in tissues differentiating at the time of wounding. An increasing lignin content and distinctively thickened walls can contribute to improved resistance as part of the compartmentalization process.

Cell Differentiation↗
PubMed2005

Quantification of the effect of vaccination on transmission of avian influenza (H7N7) in chickens.

Recent outbreaks of highly pathogenic avian influenza (HPAI) viruses in poultry and their threatening zoonotic consequences emphasize the need for effective control measures. Although vaccination of poultry against avian influenza provides a potentially attractive control measure, little is known about the effect of vaccination on epidemiologically relevant parameters, such as transmissibility and the infectious period. We used transmission experiments to study the effect of vaccination on the transmission characteristics of HPAI A/Chicken/Netherlands/03 H7N7 in chickens. In the experiments, a number of infected and uninfected chickens is housed together and the infection chain is monitored by virus isolation and serology. Analysis is based on a stochastic susceptible, latently infected, infectious, recovered (SEIR) epidemic model. We found that vaccination is able to reduce the transmission level to such an extent that a major outbreak is prevented, important variables being the type of vaccine (H7N1 or H7N3) and the moment of challenge after vaccination. Two weeks after vaccination, both vaccines completely block transmission. One week after vaccination, the H7N1 vaccine is better than the H7N3 vaccine at reducing the spread of the H7N7 virus. We discuss the implications of these findings for the use of vaccination programs in poultry and the value of transmission experiments in the process of choosing vaccine.

Animals↗
PubMed2005

rTMS of supplementary motor area modulates therapy-induced dyskinesias in Parkinson disease.

The neural mechanisms and circuitry involved in levodopa-induced dyskinesia are unclear. Using repetitive transcranial magnetic stimulation (rTMS) over the supplementary motor area (SMA) in a group of patients with advanced Parkinson disease, the authors investigated whether modulation of SMA excitability may result in a modification of a dyskinetic state induced by continuous apomorphine infusion. rTMS at 1 Hz was observed to markedly reduce drug-induced dyskinesias, whereas 5-Hz rTMS induced a slight but not significant increase.

Aged↗
PubMed2005

Integration of cognitive allocentric information in visuospatial short-term memory through the hippocampus.

Visuospatial short-term memory relies on a widely distributed neocortical network: some areas support the encoding process of the visually acquired spatial information, whereas other ares are more involved in the active maintenance of the encoded information. Recently, in a pointing to remembered targets task, it has been shown in healthy subjects that, for memory delays of 5 s, spatial errors are affected also by cognitive allocentric information, i.e., covert spatial information derived from a pure mental representation. We tested the effect of a lesion of the hippocampus on the accuracy of pointing movements toward remembered targets, with memory delays falling in the 0.5-30 s range. The spatial distributions of the two target sets we used (line and left-right) allowed the exploitation of cognitive allocentric spatial information: both sets were in the frontal plane, the line one being composed by eleven points distributed uniformly along a virtual line tilted 45 degrees away from the vertical, whereas the left-right set was composed by two workspaces symmetrically distributed at the extremes of a horizontal virtual line. We have found a significant difference between the performance of three hippocampal amnesic subjects and a group of normal controls for delays equal to or longer than 15 s, the difference being along the allocentric axis, i.e., the direction of the virtual line defined by the target set. On this basis we suggest that the hippocampal formation may enhance the spatial information processed within short-term memory with cognitive allocentric information. The association that may be operated through the neocortical-hippocampal loop of the newly acquired spatial information with well established spatial cognitive items could affect the precision of the short-term memory storage for memory delays exceeding about 15 s and might be the result of a modulation of the span of the spatial memory buffer along context-specific directions.

Adult↗
PubMed2005

Temporal lobe epileptic activity mimicking dementia: a case report.

Epileptic activity is an underdiagnosed cause that can determine a disruption of memory and cognitive performance, leading an incorrect diagnosis of dementia. We report a 68-year-old man, referred with a 5-year history of subtle behavioral changes and a subjective memory impairment, who was admitted to our department because of recurrent episodes of confusional state lasting from 1 week. Neuropsychological evaluation demonstrated a marked impairment of all cognitive domains examined. Electroencephalogram (EEG) recording showed frequent almost continuous sharp waves localized on the bilateral posterior temporal regions with mild right side predominance. Treatment with phenytoin reversed his cognitive dysfunction and behavioral disturbances. We presume that ictal temporal lobe epileptiform activity is the cause of his confusional episodes and cognitive dysfunction, showing an electroclinical picture of complex partial status epilepticus. However, we hypothesize that the interictal discharges and ictal and postictal effects of subclinical seizures could be involved in the behavioral changes and memory impairment complained by our patient in the last years.

Aged↗
PubMed2004

High-frequency rTMS improves time perception in Parkinson disease.

Patients with Parkinson disease (PD) are impaired in time processing. The authors investigated the effects of high-frequency (5 Hz) repetitive transcranial magnetic stimulation (rTMS) in patients with PD performing a time reproduction task. The authors found significant improvement in time processing induced by rTMS when trains were applied over the right dorsolateral prefrontal cortex (DLPFC) but not over the supplementary motor area, suggesting that the circuit involving the basal ganglia and the DLPFC might constitute the neural network subserving time perception.

Aged↗
PubMed2004

Overestimation of numerical distances in the left side of space.

Normal subjects presented with a middle number and two left- and right-sided outer numbers overestimate the numerical distance between the middle number and that positioned at its left side. Repetitive transcranial magnetic stimulation (rTMS) of the right posterior parietal cortex specifically counteracts this bias, suggesting that the mental representation of space defined by numbers is shifted toward the left side depending on a greater activity of the right hemisphere.

Adult↗
PubMed2004

Pergolide effect on cognitive functions in early-mild Parkinson's disease.

In the present study, we evaluated the effect of pergolide, a mixed D1/D2 agonist, on cognitive function in mild Parkinson's disease (PD). After a two-week wash-out phase, twenty patients with a Hoehn and Yahr score </=2.5 entered a 16-week, cross-over study in which the order of administration of pergolide or 1-dopa was randomly assigned. Cognitive assessment was performed after the wash-out phase and repeated after eight weeks (before patients were switched to the other drug) and at the end of the study. There were no significant differences in test scores among the three experimental modalities (off-treatment vs. l-dopa, off-treatment vs. pergolide, pergolide vs. l-dopa). In another cohort of comparably mild PD patients we had previously demonstrated that pramipexole, a mixed D2/D3 agonist, slightly but significantly worsened verbal fluency in comparison to l-dopa; moreover, pramipexole impaired short term verbal memory and attentional-executive functions in comparison to both l-dopa and the off-treatment condition. Taken together, these findings suggest that dopamine agonists may influence cognition in PD according to their pharmacological characteristics. Unlike the D2/D3 agonist pramipexole, pergolide and l-dopa, both of which stimulate D1- and D2-receptor subtypes, do not appear to impair cognitive function.

Aged↗
PubMed2004

Patient Preference for Placebo, Acetaminophen (paracetamol) or Celecoxib Efficacy Studies (PACES): two randomised, double blind, placebo controlled, crossover clinical trials in patients with knee or hip osteoarthritis.

BACKGROUND: Acetaminophen (paracetamol) is recommended as the initial pharmacological treatment for knee or hip osteoarthritis. However, survey and clinical trial data indicate greater efficacy for non-steroidal anti-inflammatory drugs and cyclo-oxygenase-2 specific inhibitors. DESIGN: Two randomised, double blind, placebo controlled, crossover multicentre clinical trials, Patient Preference for Placebo, Acetaminophen or Celecoxib Efficacy Studies (PACES). PATIENTS: Osteoarthritis of knee or hip. INTERVENTION: "Wash out" of treatment; randomisation; 6 weeks of celecoxib 200 mg/day, acetaminophen 1000 mg four times a day, or placebo; second "wash out;" crossover to 6 weeks of second treatment. MEASUREMENTS: Western Ontario McMaster Osteoarthritis Index (WOMAC), visual analogue pain scale, patient preference between two treatments. RESULTS: Celecoxib was more efficacious than acetaminophen in both periods in both studies; WOMAC and pain scale scores differed at p<0.05 in period II and both periods combined of PACES-a and in periods I and II and both periods combined in PACES-b, but not in period I of PACES-a. Acetaminophen was more efficacious than placebo, generally p<0.05 in PACES-b, and >0.05 in PACES-a. Patient preferences were 53% celecoxib v 24% acetaminophen in PACES-a (p<0.001) and 50% v 32% in PACES-b (p = 0.009); 37% acetaminophen v 28% placebo in PACES-a (p = 0.340) and 48% v 24% in PACES-b (p = 0.007). No clinically or statistically significant differences were seen in adverse events or tolerability among the three treatment groups. CONCLUSIONS: Greater efficacy was seen for celecoxib v acetaminophen v placebo, while adverse events and tolerability were similar. Variation in results and statistical significance in the two different trials are of interest.

Acetaminophen↗
PubMed2004

Different TMS patterns of intracortical inhibition in early onset Alzheimer dementia and frontotemporal dementia.

OBJECTIVE: To investigate putative changes in cortical excitability of patients affected by early-onset mild dementia by means of transcranial magnetic stimulation (TMS) and to verify whether a peculiar neurophysiological profile may contribute to characterise Alzheimer's disease (AD) vs frontotemporal dementia (FTD). METHODS: Motor threshold and intracortical inhibition (ICI) and facilitation (ICF) after paired-pulse TMS (inter-stimulus intervals from 1 to 20 ms) were studied in two groups of early-onset demented patients with a neuropsychological profile suggestive of AD (n = 12) and FTD (n = 8). Twelve age-matched healthy subjects were considered as control group. In both patient groups, recordings were performed before and after a single oral dose of 4 mg galantamine. RESULTS: No significant difference in motor threshold was observed among the three studied groups. On the contrary, early-onset AD showed a significant reduction of ICI compared to control group, no changes were detected in FTD patients. No significant changes in ICF were found between both patient groups and healthy subjects. The acute administration of galantamine reversed the modified ICI in AD group. CONCLUSIONS: The differential pattern of ICI exhibited by early-onset AD vs FTD in the early stage of disease may represent a non-invasive, reproducible electrophysiological tool, which may contribute to early differential diagnosis and, possibly, to monitor therapeutic effectiveness. SIGNIFICANCE: The present results support the possibility that subtle, early modifications in intracortical circuitry features AD, but not FTD patients.

Aged↗
PubMed2004

A cross-sectional serological survey of the Dutch commercial poultry population for the presence of low pathogenic avian influenza virus infections.

After the discovery of poultry infected with highly pathogenic avian influenza (HPAI) virus of subtype H7N7 in the central area of The Netherlands on 28 February 2003, the hypothesis was put forward that an outbreak of the low pathogenic (LP) variant of H7N7 had preceded, unnoticed, the occurrence of the HPAI virus. Consequently, a cross-sectional serological survey of the Dutch poultry population was executed in the second week of March 2003. The basic requirements set were detection of a 5% prevalence of flocks exposed to LPAI virus with 95% confidence within the production type stratification level within each province in The Netherlands. Because of supposed higher risk of avian influenza infections in ducks, turkeys and free-range poultry, all the commercial flocks of these production types present in The Netherlands were sampled. The serological screening of 28018 sera from 1193 randomly selected poultry farms, located outside surveillance zones showed that LPAI H7 virus infections had occurred on three neighbouring farms all located in the southwest of The Netherlands. No antibodies against the neuraminidase N7 subtype were detected in the sera of these farms, indicating that the subtype was different from the HPAI H7N7 subtype that caused the avian influenza epidemic in 2003. In addition, evidence of infections with non-H5 or non-H7 subtypes of influenza A virus were obtained in two other farms located in the northeast and the southeast of The Netherlands. It was concluded that the HPAI subtype H7N7 outbreak was most likely not preceded by a significant circulation of a LPAI subtype H7N7 virus. Based on the Dutch experience, recommendations are made to detect avian influenza infections faster in the future.

Animals↗
PubMed2004

Simultaneous detection and differentiation of anti-Helicobacter pylori antibodies by flow microparticle immunofluorescence assay.

Helicobacter pylori is the key pathogen for gastroduodenal diseases. The clinical outcome of H. pylori infection is influenced by the presence of strain-specific virulence factors that are usually detected by the presence of specific anti-H. pylori antibodies in serum. Apart from the detection of these antibodies by enzyme-linked immunosorbent assay (ELISA), it is desirable to obtain additional information concerning the presence of certain virulence factors of H. pylori that are currently detected by immunoblot analysis. At present, the immunodiagnosis of an H. pylori infection includes two separate methods: ELISA and immunoblot analysis. Here, we report the development and evaluation of a new rapid flow microparticle immunofluorescence assay (FMIA) for detection of anti-H. pylori antibodies in human serum. The assay allows rapid qualitative and quantitative detection of anti-H. pylori antibodies by using crude antigen preparations as well as single recombinant antigens (urease A, urease B, CagA, and alkylhydroxy peroxide reductase) in the same sample with one measurement, and thus it combines the advantages of enzyme immunoassay and Western blot analysis. Seventy-five patient samples were analyzed by FMIA, ELISA, and Western blotting with respect to their immunoreactivity against crude H. pylori extracts and individual H. pylori antigens. Statistical analyses revealed an overall similarity of more than 90% among the results for FMIA, ELISA, and Western blot. Therefore, we conclude that FMIA is a powerful and time- and cost-saving assay system for the detection of antimicrobial antibodies, with higher sensitivity and a larger measurement range than ELISA.

Antibodies, Bacterial↗