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Biomedical subjects

G Koch

Publications and source records attributed to G Koch.

At least 73 records · Page 4Linked to original sources
PubMed2000

Caries prevalence and distribution in 20-80-year-olds in Jönköping, Sweden, in 1973, 1983, and 1993.

In 1973, a cross-sectional study on oral health status was performed on 1000 individuals in the age groups 3-70 years in Jönköping, Sweden. In 1983 and 1993, new cross-sectional studies were carried out in the age groups 3-80 years. The aim of the present study was to analyze caries prevalence and distribution in the three investigations 1973, 1983, and 1993 in the age groups 20-80 years. In the younger age groups (20-40 years), a larger proportion of individuals with good oral health was found in 1993 than in 1973 or 1983. A steady increase in the number of teeth in the age groups 40-80 years could be found, which was also reflected in the increasing number of decayed and filled tooth surfaces (DFS) in the same age groups. A marked decrease in proximal DFS in 20-50-year-olds in 1993 compared to 1973 and 1983 was found. However, a rather large and unchanging group of individuals suffering from severe caries was also observed. This situation demands an individualized caries treatment strategy based on risk assessment.

Adult↗
PubMed2000

Defence mechanisms against viral infection in poultry: a review.

Defence against viral infections in poultry consists of innate and adaptive mechanisms. The innate defence is mainly formed by natural killer cells, granulocytes, and macrophages and their secreted products, such as nitric oxide and various cytokines. The innate defence is of crucial importance early in viral infections. Natural killer cell activity can be routinely determined in chickens of 4 weeks and older using the RP9 tumour cell line. In vitro assays to determine the phagocytosis and killing activity of granulocytes and macrophages towards bacteria have been developed for chickens, but they have not been used with respect to virally infected animals. Cytokines, such as interleukin (IL)-1, IL-6 and tumour necrosis factor (TNF)-alpha, are indicators of macrophage activity during viral infections, and assays to measure IL-1 and IL-6 have been applied to chicken-derived materials. The adaptive defence can be divided into humoral and cellular immunity and both take time to develop and thus are more important later on during viral infections. Various enzyme-linked immunosorbent assays (ELISAs) to measure humoral immunity specific for the viruses that most commonly infect poultry in the field are now commercially available. These ELISAs are based on a coating of a certain virus on the plate. After incubation with chicken sera, the bound virus-specific antibodies are recognized by conjugates specific for chicken IgM and IgG. Cytotoxic T lymphocyte activity can be measured using a recently developed in vitro assay based on reticuloendotheliosis virus-transformed target cells that are loaded with viral antigens, e.g. Newcastle disease virus. This assay is still in an experimental stage, but will offer great opportunities in the near future for research into the cellular defence mechanisms during viral infections.

Animals↗
PubMed2000

Codominant analysis of banding data from a dominant marker system by normal mixtures.

Amplified fragment length polymorphisms (AFLPs) currently are among the most widely used marker systems. In many studies, AFLPs are analyzed on the basis of the presence or absence of a band on an electrophoretic gel. As a result, dominant homozygous individuals are not distinguished from heterozygous individuals, resulting in a considerable loss of information. This article shows how codominant information can be obtained if the amount of PCR products is quantified. Due to measurement variation, genotyping on the basis of such information is not error-free. We propose use of normal mixture distributions to determine the most likely genotype, given the data. The method is exemplified using AFLP data from sugar beet.

Analysis of Variance↗
PubMed2000

Specialized dementia programs in residential care settings.

The authors conducted a telephone survey in 7 states to determine the prevalence of residential care specialized dementia programs (RC-SDPs) and to identify a sample of homes (n = 56) for more detailed study. The 56 homes were site visited, and data were gathered on facility administration, therapeutic environment, and characteristics of 259 randomly selected residents. Comparison data from 138 nursing home Special Care Units (NH-SCUs) and 1,340 of their residents were obtained from 4 studies conducted in the same 7 states. RC-SDPs were smaller, provided a more homelike environment, and had a higher proportion of residents paying privately, compared with NH-SCUs. Mean levels of cognitive and physical impairment among residents were higher in NH-SCUs; prevalences of psychotropic medication use and problem behaviors were similar. Among RC facilities, small homes were more homelike, provided fewer structured activities, and charged less than larger facilities. RC-SDPs include 5 types: small, independently operated homes; multiple small homes with joint administration; larger, all-dementia facilities; SDPs operated within larger, exclusively RC facilities; and RC-SDPs in multilevel facilities.

Aged↗
PubMed2000

Cerebrospinal fluid drainage to reverse paraplegia after endovascular thoracic aortic aneurysm repair.

PURPOSE: To report a case of endovascular descending thoracic aortic aneurysm (TAA) repair in which delayed-onset paraplegia was reversed using cerebrospinal fluid (CSF) drainage. METHODS AND RESULTS: A 74-year-old patient with a 6.0-cm TAA underwent endovascular stent-graft repair that involved overlapping placement of 3 Talent devices to cover the 31-cm-long defect. Twelve hours later, a neurological deficit occurred manifesting as left leg paralysis with paresis on the right. After urgent intrathecal catheter placement and drainage of cerebrospinal fluid for 48 hours, the neurological deficit resolved. The patient's clinical condition was normal and endoluminal exclusion of the TAA remained secure at 8-month follow-up. CONCLUSIONS: This case demonstrates the potential therapeutic role for CSF drainage to reduce the complications of spinal cord injury after endovascular thoracic aneurysm repair.

Aged↗
PubMed2000

Studies on the pathogenesis of chicken infectious anaemia virus infection in six-week-old SPF chickens.

The pathogenesis of chicken infectious anaemia virus (CAV) infection was studied in 6-week-old and one-day-old SPF chickens inoculated intramuscularly with graded doses of Cux-1 strain (10(6)-10(2) TCID50/chicken). Viraemia, virus shedding, development of virus neutralizing (VN) antibodies and CAV distribution in the thymus were studied by virus isolation, polymerase chain reaction (PCR), immunocytochemistry (IP) and in situ hybridization until postinfection day (PID) 28. In 6-week-old chickens infected with high doses of CAV, viraemia and VN antibodies could be detected 4 PID and onward without virus shedding or contact transmission to sentinel birds. However, virus shedding and contact transmission were demonstrated in one-day-old infected chickens. In the 6-week-old groups infected with lower doses, VN antibodies developed by PID 14, transient viraemia and virus shedding were detected. The thymus cortex of all 1-day-old inoculated chickens stained with VP3-specific mAb. Cells with positive in situ hybridization signal were fewer and scattered throughout the thymus tissue of the one-day-old inoculated chickens as compared to IP-positive cells. These results suggest that early immune response induced by high doses of CAV in 6-week-old chickens curtails viral replication and prevents virus shedding.

Aging↗
PubMed2000

[Primary bacterial aortitis].

Primary bacterial aortitis represents a rare disease with a high lethality. From June 1997 to April 1999 5 patients with an abdominal aortic infection were treated by resection of the infected aorta and in-situ reconstruction or by extra-anatomic bypass. There was no treatment in one case because of the infaust prognosis. 3 patients survived, one with a paraparesis as a result of spinal ischemia. On the basis of our patients the pathogenesis, clinical symptoms with diagnosis and the therapeutic options are discussed.

Aged↗
PubMed2000

Metabolic aspects of myocardial disease and a role for L-carnitine in the treatment of childhood cardiomyopathy.

OBJECTIVES: A multicenter retrospective study was conducted to investigate the possible metabolic causes of pediatric cardiomyopathy and evaluate the outcome of patients treated with L-carnitine. METHODS: Seventy-six patients diagnosed with cardiomyopathy were treated with L-carnitine in addition to conventional cardiac treatment, and 145 patients were treated with conventional treatment only. There were 101 males and 120 females between 1 day and 18 years old. Cardiomyopathy diagnoses included dilated (148 patients), hypertrophic (42 patients), restrictive (16 patients), mixed diagnosis (11 patients), and 4 with an unknown type. Of 76 L-carnitine-treated patients, 29 (38%) had evidence to suggest a disorder of metabolism, and of 145 control patients, 15 (10%) were suspected to have a disorder of metabolism. These metabolic disorders were thought to be the cause for the cardiomyopathy of the patients. The duration of L-carnitine treatment ranged from 2 weeks to >1 year. Information was collected on length of survival (time-to-event), clinical outcome, echocardiogram parameters, and clinical assessments. Data were collected at intervals from baseline to study endpoint, death, transplant, or last known follow-up visit. RESULTS: L-Carnitine-treated patients were younger than control patients and had poorer clinical functioning at baseline, yet they demonstrated lower mortality and a level of clinical functioning and clinical severity comparable to control patients on conventional therapy by the end of the study. An analysis of the interaction between clinical outcome and concomitant medications unexpectedly revealed that the population of patients treated with angiotensin-converting enzyme (ACE) inhibitors (40% of patients) had significantly poorer survival (although their greater likelihood for poor survival may possibly have made them more likely to receive ACE inhibitors). CONCLUSION: Results suggest that L-carnitine provides clinical benefit in treating pediatric cardiomyopathy. There is a need for further exploration of potential explanatory factors for the higher mortality observed in the population of patients treated with ACE inhibitors.

Cardiomyopathies↗
PubMed1999

Isolation, characterization and cDNA cloning of nicotianamine synthase from barley. A key enzyme for iron homeostasis in plants.

Basic cellular processes such as electron transport in photosynthesis and respiration require the precise control of iron homeostasis. To mobilize iron, plants have evolved at least two different strategies. The nonproteinogenous amino acid nicotianamine which is synthesized from three molecules of S-adenosyl-L-methionine, is an essential component of both pathways. This compound is missing in the tomato mutant chloronerva, which exhibits severe defects in the regulation of iron metabolism. We report the purification and partial characterization of the nicotianamine synthase from barley roots as well as the cloning of two corresponding gene sequences. The function of the gene sequence has been verified by overexpression in Escherichia coli. Further confirmation comes from reduction of the nicotianamine content and the exhibition of a chloronerva-like phenotype due to the expression of heterologous antisense constructs in transgenic tobacco plants. The native enzyme with an apparent Mr of approximately 105 000 probably represents a trimer of S-adenosyl-L-methionine-binding subunits. A comparison with the recently cloned chloronerva gene of tomato reveals striking sequence homology, providing support for the suggestion that the destruction of the nicotianamine synthase encoding gene is the molecular basis of the tomato mutation.

Alkyl and Aryl Transferases↗
PubMed1999

Map-based cloning of chloronerva, a gene involved in iron uptake of higher plants encoding nicotianamine synthase.

The uptake of iron in plants is a highly regulated process that is induced on iron starvation. In tomato, the mutant chloronerva exhibits constitutive expression of iron uptake responses and intercostal chlorosis. Biochemically, chloronerva is an auxotroph for nicotianamine, a key polyamine in plant iron uptake metabolism. The chloronerva gene has been fine-mapped onto the long arm of chromosome 1 in a large segregating tomato population and yeast artificial chromosome clones encompassing the region were isolated by using flanking markers. A cosmid contig containing the chloronerva gene was established, and complementing cosmids were identified by transformation into the mutant. The chloronerva transcript was identified by cDNA isolation using the complementing cosmids. The gene encodes a unique protein of 35 kDa. The mutant harbors a single base change compared with the wild type. Based on enzyme activity and sequence similarity to the coding DNA sequence of the purified barley enzyme the chloronerva gene encodes the enzyme nicotianamine synthase.

Alkyl and Aryl Transferases↗
PubMed1999

[Therapy of phantom pain with salmon calcitonin and effect on postoperative patient satisfaction].

In this prospective clinical study we examined the intravenous application of salmon-calcitonin in eight patients with severe phantom limb pain (Visual Analogue Scale = 50-100). The patients presented at the Acute Pain Service (APS) section of the Second Department of Surgery, University of Cologne. Six of eight patients (75%) had no phantom limb pain after 10 days of intravenous treatment with salmon-calcitonin (maximum of five cycles of calcitonin infusion). Systematic follow-up examinations after 3, 6 and 12 months showed long-term success. Patient satisfaction was examined with a numeric rating scale (NRS 1-6) between the single infusion cycles. When patient satisfaction was low, the physician modified the time period or drug dosage between infusions. This study shows good or excellent results in patient satisfaction for six of eight patients (75%). A prospective randomized trial is required to verify the excellent results of intravenous salmon-calcitonin in a larger population. Alternative pharmacological and operative treatments of phantom limb pain are critically reviewed and assessed.

Adult↗
PubMed1999

[Posttraumatic aneurysm of the brachiocephalic trunk: a rare injury].

We report on a posttraumatic aneurysm of the brachiocephalic trunk, something which is rather rare. The injury was caused by blunt chest trauma following a car accident. Computed tomography could not find the brachiocephalic lesion. In patients with fractures of the upper ribs after blunt chest trauma, angiography should be done to exclude severe injuries of the aorta and brachiocephalic vessels.

Adult↗
PubMed1999

Endoluminal treatment of infrarenal aortic aneurysms: clinical experience with the Talent stent-graft system.

PURPOSE: To evaluate the safety and efficacy of the Talent stent-graft (TSG) system in the endoluminal treatment of infrarenal abdominal aortic aneurysms (AAAs). PATIENTS AND METHODS: Endoluminal treatment of an AAA was attempted in 30 men with a mean age of 70.5 years (range, 51-83 years). Seven patients had AAAs suitable for treatment with a tube graft. In the other patients, treatment with a bifurcated TSG was planned. All procedures were performed as a combined surgical-radiologic procedure in an angiographic room. RESULTS: Primary technical success was achieved in 25 of 30 patients (83%). Technical failures were due to misplacement of the TSG (n = 2) with proximal leakage as a consequence, inability to gain access via the iliac arteries (n = 1), and a distal leakage (n = 2). Secondary interventions (n = 2) and spontaneous thrombosis of a distal leak (n = 1) increased the secondary technical success rate to 93% (28 of 30). Two procedures were converted to open surgery (conversion rate = 6%). One patient died during the first 30 days after uncomplicated stent-graft insertion because of myocardial infarction (30-day mortality = 5%). No complications occurred during a mean follow-up of 15.4 months (range, 6-19 months). The maximum diameter of the AAA decreased in eight patients and remained unchanged in the remaining patients. No increase in diameter was observed. No late endoleak or migration of the TSG was observed. CONCLUSION: The TSG-system revealed satisfactory initial and early follow-up results. Treatment of AAAs with this stent-graft system is feasible. The technical success rate in carefully selected patients should be 90% or more. However, long-term observations are necessary to determine if the encouraging early results of this type of therapy can be preserved during long-term follow-up.

Aged↗
PubMed1999

Aortoduodenal fistula: a late complication of intraluminal exclusion of an infrarenal aortic aneurysm.

During recent years, considerable clinical experience has been gained with endoluminal stent-graft procedures. Several studies have shown promising results up to a period of 4.5 years. However, long-term follow-up studies are still limited. Late endoleaks caused by stent-graft migration, disconnection of single components in modular stent-grafts, and limb thrombosis have been observed as long-term complications. We report a case in which a migrated and kinked bifurcated stent-graft caused an aortoduodenal fistula 20 months after stent-graft insertion. To our knowledge, such a complication has not been reported before.

Aorta, Abdominal↗