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Biomedical subjects

J Freudenberg

Publications and source records attributed to J Freudenberg.

At least 19 recordsLinked to original sources
PubMed2002

A similarity-based method for genome-wide prediction of disease-relevant human genes.

MOTIVATION: A method for prediction of disease relevant human genes from the phenotypic appearance of a query disease is presented. Diseases of known genetic origin are clustered according to their phenotypic similarity. Each cluster entry consists of a disease and its underlying disease gene. Potential disease genes from the human genome are scored by their functional similarity to known disease genes in these clusters, which are phenotypically similar to the query disease. RESULTS: For assessment of the approach, a leave-one-out cross-validation of 878 diseases from the OMIM database, using 10672 candidate genes from the human genome, is performed. Depending on the applied parameters, in roughly one-third of cases the true solution is contained within the top scoring 3% of predictions and in two-third of cases the true solution is contained within the top scoring 15% of predictions. The prediction results can either be used to identify target genes, when searching for a mutation in monogenic diseases or for selection of loci in genotyping experiments in genetically complex diseases.

Algorithms↗
PubMed2000

Simulation of cardiac excitation patterns in a three-dimensional anatomical heart atlas.

Computerized anatomical atlas systems enable interactive investigation of digital body models. Here we present a three-dimensional atlas of the human heart, based on image data provided in the Visible Human Project. This heart atlas consists of multiple kinds of cardiac tissues and offers unlimited possibilities for its visual exploration. A temporal dimension is added to the underlying heart model by simulation of cardiac excitation spreading. For this purpose a second generation cellular automata algorithm is adapted to the excitation kinetics of cardiac tissue. The presented system is shown as a successful method for the visualization-based investigation of cardiac excitation.

Algorithms↗
PubMed1999

A contactless surface acoustic wave biosensor.

Surface acoustic wave sensors operating in liquid generally cause problems resulting from wire bonding. The authors present an approach for a biosensor where the need for bonding wires is eliminated by utilizing inductive coupling of the sensor device to the RF circuitry. Protection of the electrodes from the liquid is achieved by coating the device surface with a SiO2 layer, resulting in a simplified handling of the devices. The first measurements with a sensor operating at 420 MHz are presented, demonstrating the potential of this operating principle for biosensing.

Acoustics↗
PubMed1998

Platelet-activating factor mediates monocyte chemoattractant protein-1 expression in glomerular immune injury.

These studies were designed to determine the possible role of platelet-activating factor (PAF) in the production of monocyte chemoattractant protein-1 (MCP-1) in glomerular immune injury. The glomerular lesion was induced in isolated perfused rat kidneys by a rabbit anti-rat-thymocyte serum (ATS) and rat serum (RS) as a complement source. Perfusion of kidneys with ATS and RS results in the selective binding of the antiserum to the glomerular mesangium with consecutive intraglomerular activation of complement. Antibody binding and complement activation induced a significant increase in glomerular MCP-1 mRNA levels when assessed by Northern blotting or RT-PCR. Decomplemented RS or non antibody rabbit IgG had only moderate effects on glomerular MCP-1 mRNA levels. The PAF receptor antagonist WEB 2170 almost completely blocked the ATS and RS induced MCP-1 mRNA levels. Perfusion of control kidneys with PAF increased MCP-1 mRNA expression, an effect which was blocked by WEB 2170. Glomerular MCP-1 protein formation, assessed by Western blotting, was stimulated following ATS and RS and PAF, respectively, was blocked by WEB 2170. These data show that PAF, derived from glomerular resident cells following antibody and complement induced injury, stimulates MCP-1 expression. In addition to the direct effects on leukocyte adhesion and activation PAF may mediate inflammatory cell influx in glomerular injuries due to the release of MCP-1.

Animals↗
PubMed1997

[Malignant hyperthermia and sevoflurane--a case report].

The authors report on a course of malignant hyperthermia (MH) in an almost 5-years old boy. In the past, he had been anaesthetized two times with halothane without complications. The causative triggering agent was sevoflurane, a new user-friendly substance for paediatric anaesthesia. Forty five minutes after induction of anaesthesia he developed symptoms of a MH-crisis with increase in endexspiratory CO2 up 87 mmHg and followed by an increase in heart rate up to 160 beats/minute. The blood gas analysis showed a respiratory and metabolic acidosis. The timely administration of dantrolene rapidly reversed the life-threatening signs and prevent progression of the disease. It is apparent that monitoring of endtidal carbon dioxide by means of capnometry is of crucial importance in detecting MH at an early stage, and appropriate treatment is being instituted more promptly. By such early recognition, and treatment with dantrolene, we can reasonably except a further decrease in mortality and morbidity of this enigmatic disorder.

Anesthetics, Inhalation↗
PubMed1996

Prostaglandin E1 reduces the glomerular mRNA expression of monocyte-chemoattractant protein 1 in anti-thymocyte antibody-induced glomerular injury.

To study whether prostaglandins (PG) can regulate the mRNA expression of monocyte-chemoattractant protein 1 (MCP-1) in glomerular immune injury, MCP-1 mRNA levels were evaluated in anti-thymocyte antibody (ATS) -induced glomerular injury by Northern blotting and reverse transcription-polymerase chain reaction. Immune injury was induced in vivo by the intravenous application of ATS to male Wistar rats and in vitro by the perfusion of isolated rat kidneys with ATS and rat serum. In vivo 3 h and 5 days after antibody application, glomerular mRNA expression of MCP-1 was markedly enhanced compared with controls. In the isolated perfused kidney, antibody and complement also induced an increase in MCP-1 expression at 10 min and 60 min after antibody perfusion. When the rats were treated with PGE (250 micrograms, twice daily), the increase in MCP-1 expression was reduced. This was associated with a reduction of intraglomerular recruitment of monocytes/macrophages. In the isolated perfused kidneys, PGE1 (1 mg/L) prevented the antibody- and rat serum-stimulated increase in glomerular MCP-1 mRNA expression. These data demonstrate that PGE1 reduces glomerular MCP-1 mRNA expression in glomerulonephritis and in the isolated perfused rat kidney after induction of immune injury with antibody and complement. The data suggest that prostaglandins might mediate MCP-1 effects in glomerular immune injuries.

Alprostadil↗
PubMed1994

[Pituitary crisis and acute renal failure--a case report].

Based on a case report, the combined occurrence of a hypopituitary crisis and acute renal failure (ARF) is discussed. Aetiologically, the patient's disease dates back to an operation on the pituitary gland 40 years previously followed by a panhypopituitarism. The course of the disease presented initial symptoms which did not suggest a hypopituitary crisis to the first physician. The patient was hospitalized primarily on the tentative diagnosis of encephalitis. Subsequently, both laboratory findings and sonography of the abdomen pointed to chronic renal failure. The severity of the clinical course led to the transfer of the patient to our hospital for haemodialysis. Examination of the soporous patient revealed in addition to symptoms of ARF based on ambilateral pyelonephritic nephrocirrhosis typical cardinal symptoms of an endocrine insufficiency. Sopor, serious exsiccosis, pale, cool, pigmentless skin, deficiency of axillary and pubic hair, gonadal atrophy, hypotonia, hypothermia, bradypnoea and bradycardia as well as anamnesis of the patient substantiated the tentative diagnosis of a hypophysical coma based on hypopituitarism, clinically dominated by hypothyroidism. Following an immediately launched hormone substitution in combination with haemodialysis the state of the patient improved. However, during the fifth haemodialysis cardiac arrest occurred, the cause of which was put down to a dysequilibrium syndrome. The cause, however, must be seen in a continuing stress situation, inadequate hormone substitution and in sedation with diazepam. After reanimation the patient was transferred to the ICU.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1991

Comparison of plateletpheresis with two different cell separators using 100 identical donors.

Plateletpheresis with the cell separator COBE Spectra and Fenwal CS 3000 was compared in 100 identical donors. The Spectra was significantly superior with regard to collection efficiency (53% vs. 42%, p less than .001) and leukocyte contamination of the platelet products (.1 x 10(8) vs. 1.4 x 10(8), p less than .001). Additionally, it offers a selectable volume of the concentrate and a better control of the ACD infusion. The Spectra standard procedure needs more ACD, resulting in more citrate dependent donor reactions (5% vs. 1%). In conclusion, the Spectra system shows a more efficient and pure platelet separation compared with the CS 3000.

Adolescent↗
PubMed1989

[Blood donor selection in providing anticytomegalovirus-negative blood components].

Sera of 1731 blood donors of the Ulm blood bank were screened for cytomegalovirus (CMV) antibodies. Prevalence of these antibodies was 37%. The seroconversion rate among 1090 anti-CMV-negative blood donors was 13 per thousand per year for the whole donor population over a period of 27 months and depended on age. It was 16 per thousand per year for donors aged 18-40 years, but only 7 per thousand for those over 41 years old. Seropositivity was higher in women than men. To provide anti-CMV-negative blood requires a prescreened anti-CMV-negative donor group and the rescreening of each further donated blood component.

Adolescent↗
PubMed1980

HLA antigen frequencies in patients with Huntington's chorea and their relatives.

Twenty patients with Hungtington's chorea and 30 family members were typed for 30 antigens of the HLA-A, B, and C series. There was an increased frequency of HLA-BW 16, significant at the 1%-level. After correcting for multiple inferences, the association of HLA-BW 16 with Huntington's chorea was no longer statistically significant. There was also no reliable indication of coupling between HLA antigens and Huntington's chorea in the family studies.

Adult↗
PubMed1978

[HLA antigen frequencies in patients with progressive systemic sclerosis and morphea (author's transl)].

Forty three patients with progressive systemic sclerosis and 24 patients with morphea are typed for 30 antigens of the HLA-A and B series. There is an increase of the frequency of HLA-B8 in patients with progressive systemic sclerosis (37% vs. 20% in controls: P less than 0.001, Pcorr. = n.s.). The increase of the HLA-B8 frequency seems to be most pronounced in patients with a diffuse form of progressive systemic sclerosis. 4 out of 5 patients are HLA-B8 positive (P = 0.00672). In patients with acrosclerosis is HLA-B8 only slightly increased (32%), but the increase is greater in male patients (44%) and in patients with an early onset of the disease (36%). With the exception of HLA-A1 there is no deviation of the frequencies of any other HLA antigen tested, especially not of HLA-Aw24. The number of patients with morphea is to small for statistical evaluation.

Adult↗
PubMed1977

HLA in different forms of chronic active hepatitis. A comparison between adult patients and children.

108 adult patients and 34 children with chronic active hepatitis (CAH) are divided in four groups on the basis of presence and absence of hepatitis B surface antigen (HBsAg) and autoantibodies (AutoAb). There are significant differences in the numeric distribution among the four groups and the sex distribution between adult patients and children, but no differences in the frequencies of the HLA antigens tested. An increased frequency of HLA-B8 (and HLA-A1) compared with normal controls and the other groups is only found in autoimmune types of CAH, characterized as HBsAg-negative, AutoAb-positive CAH. HBsAg-negative, AutoAb-negative forms of CAH are called cyptogenic CAH and these are most likely non-hepatitis B virus induced types of CAH. In these and hepatitis B virus induced forms of CAH no significant deviation of any HLA antigen tested could be found.

Adolescent↗
PubMed1976

[Histocompatibility-(HLA) antigens in patients with HBsAg positive and negative hepatitis and healthy carriers of HBsAg and anti-HBs. (author's transl)].

New own data and a survey of published data concerning the frequencies of 23 HLA antigens in patients with HBsAg positive and negative chronic active hepatitis (CAH) and healthy carriers of Hepatitis-surface antigen (HBsAg) and high titers of antibodies to HBaAg (Anti-HBs) allow to conclude as follows: 1. Patients with CAH and persistence of HBsAg show a normal frequency of HLA-B8. 2. There is no increased frequency of HLA-B8 in HBsAg negative CAH without autoimmune antibodies. 3. Only in patients with HBsAg negative CAH with autoimmune antibodies is the frequency of HLA-B8 is statistically significantly increased (p less than 0.01 after correction for the number of antigens and different groups of patients compared). These are patients with the autoimmune form of CAH. 4. There exist no significant differences in the frequencies of the HLA antigens tested in patients with HBsAg positive CAH and healthy carriers of HBsAg and Anti-HBs. Thus no indications could be found for HLA-associated factors in the different behaviour to the hepatitis-B virus.

Adult↗
PubMed1975

Organ-specificity and diagnostic value of cell-mediated immunity against a liver-specific membrane protein: studies in hepatic and non-hepatic diseases.

In chronic active hepatitis (CAH, n=58) 70% of the HBsAg negative and 48% of the HBsAg positive cases showed a CMI against human liver specific proteins (HLPI). Using HBsAg as antigen only 12% of the HBsAg negative and 24% of the HBsAg positive cases gave a CMI response. On the basis of HBsAg and autoantibodies in the serum CAH patients could be divided into 4 subgroups. A close correlation between CMI against HLPI, sex, ANA and HL-A-8 could be detected. In a follow-up study of patients with acute virus B hepatitis (n=62) CMI against HBsAg was detected in 60% of the cases in the acute phase of the disease but in 15% only 3-6 months after the onset of the illness (n=40). In patients who developed a chronic HBsAg carrier status 3 of 5 cases remained persistently positive with HLPI as antigen in the migration inhibition test. - In non-hepatic diseases in which immunological abnormalities may be present (malignant diseases n=46, diabetes mellitus n=27, active tuberculosis, n=18 and untreated systemic lupus erythematodes, n=5) only 26% of patients with malignant diseases showed a migration inhibition with HLPI. - Using different antigens such as human liver specific proteins (HLP), rabbit liver specific proteins (RLP), brucella suis antigen and tuberculin it was possible to demonstrate the validity of the two-step migration inhibition test to detect CMI. The results with different antigens in hepatic and non-hepatic diseases demonstrated that cell-mediated immunity of HLPI is an organ specific immune reaction which is associated with acute and chronic active liver diseases as a time limited or long-lasting phenomenon. Positive reactions in some tumor patients suggest that different mechanisms may elicit an autoimmune reaction against liver antigens.

Antibodies↗