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Biomedical subjects

H Hofmann

Publications and source records attributed to H Hofmann.

At least 19 recordsLinked to original sources
PubMed1992

Effects of ribose on exercise-induced ischaemia in stable coronary artery disease.

There is no established treatment specifically aimed at protecting or restoring cardiac energy metabolism, which is greatly impaired by ischaemia. Even after reperfusion, myocardial content of ATP remains low for more than 72 h. Long-term post-ischaemic dysfunction and irreversibility of ischaemic damage have been associated with low ATP content. Evidence that the pentose sugar ribose stimulates ATP synthesis and improves cardiac function led us to test the possibility that ribose increases tolerance to myocardial ischaemia in patients with coronary artery disease (CAD). 20 men with documented severe CAD underwent two symptom-limited treadmill exercise tests on 2 consecutive days; we postulated that the ischaemia induced might bring about changes in ATP metabolism lasting for several days. Patients whose baseline tests showed reproducibility were randomly allocated 3 days of treatment with placebo or ribose 60 g daily in four doses by mouth. Exercise testing was repeated after treatment on day 5. At that time mean (95% confidence interval) treadmill walking time until 1 mm ST-segment depression was significantly greater in the ribose than in the placebo group (276 [220-331] vs 223 [188-259] s; p = 0.002). The groups did not differ significantly in time to moderate angina. In the ribose-treated group the changes from baseline to day 5 in both time to ST depression and time to moderate angina were significant (p less than 0.005), but these changes were not significant in the placebo group. In patients with CAD, administration of ribose by mouth for 3 days improved the heart's tolerance to ischaemia. The presumed effects on cardiac energy metabolism offer new possibilities for adjunctive medical treatment of myocardial ischaemia.

Aged↗
PubMed1992

Prevalence of hepatitis-C virus infection in children with chronic post-transfusion hepatitis.

The prevalence of hepatitis-C virus (HCV) infection was investigated in a group of children with chronic post-transfusion hepatitis using a first- and second-generation HCV-antibody ELISA, 2 confirmatory tests (a second-generation recombinant immunoblot assay and a line immunoassay) as well as an HCV-polymerase chain reaction (PCR). In 33% of the children, clear discrepancies were observed between the 4 different HCV-antibody detection assays, indicating that the serological diagnosis of HCV infection is still problematic. HCV RNA was detectable by PCR in only 69% of the antibody positive patients, which may be due to a fluctuation of viraemia during the course of infection. Such a fluctuation was demonstrated in 6 patients from whom serum samples drawn at different times were investigated. In contrast, in 8 of the 15 seronegative patients, HCV infection was identified only by PCR, although the hepatitis had already persisted for more than 2 years. Antibody assays and PCR together detected HCV infection in about 90% of the patients with chronic hepatitis. When markers of hepatitis B infection were also investigated, only 6% of the cases remained undiagnosed.

Base Sequence↗
PubMed1991

Amniotic fluid N-acetyl-beta-D-glucosaminidase activity and renal abnormalities.

Amniotic fluid N-acetyl-beta-D-glucosaminidase (NAG) activity was measured in 21 normal pregnancies to determine reference values, and in 10 pregnancies with fetuses who had prenatally recognised renal and urinary tract malformations. The normal values obtained at 17-19 and 28-31 gestational weeks did not differ, and an activity of 105 units NAG/mmol creatinine was the upper limit of the normal range. Raised NAG activities were found in four fetuses with oligohydramnios and severe bilateral renal disease, and also in two infants with a normal amount of amniotic fluid, only unilateral renal lesions, and a normal renal function after birth. Three of four cases with normal NAG activities had malformations without kidney damage, but one baby with prune belly syndrome was subsequently found to have dysplastic kidneys and renal failure. Our preliminary results suggest that a high level of NAG activity in the amniotic fluid indicates unilateral or bilateral kidney damage but is not proof of intrauterine renal failure.

Acetylglucosaminidase↗
PubMed1991

Prenatal diagnosis of myotonic dystrophy using closely linked flanking markers.

We report on two cases of prenatal diagnosis of myotonic dystrophy (DM), using flanking markers APOC2 or CKMM on the proximal side and D19S51 on the distal side. By double digestion (TaqI and NcoI) of PCR amplified CKMM, the informativeness was increased from a PIC value of 0.57 to 0.69. Altogether, with a PIC value of 0.64 for APOC2, 0.69 for CKMM, and 0.27 for D19S51 (BglI), presymptomatic and prenatal diagnosis can thus be offered to approximately 24% of persons with a risk between 0.0004 and 0.0008 using these flanking markers.

Adult↗
PubMed1991

[Mass screening of blue color vision in divers with the desaturated Lanthony-15-Hue Test].

We tested 1002 persons, 572 divers (including 38 who had diving accidents) and 430 nondivers, for defects of the blue-sensitive system during the years 1988 and 1989. Recent research has shown functional disorders of color vision in divers, linked to previously described alterations of the retinal capillary system and pigment epithelium. The desaturated Lanthony-15-HUE test was used as a screening method. No defect of the blue-sensitive system was found, either in divers or in nondivers. Our results are similar to those of other researchers. One exception was that we found no correlation between age and error score. We found no evidence for retinal damage caused by diving.

Adult↗
PubMed1991

[Hepatitis C antibodies in children and adolescents with congenital blood coagulation disorders].

Antibodies to hepatitis C (anti-HCV) were determined in 24 children and adolescents with congenital disorders of haemostasis. 13 out of 24 patients (54%) were positive for anti-HCV. Comparison of the prevalence of positive anti-HCV and the quantity of non-virus inactivated factor VIII concentrates administered before 1985 showed positive anti-HCV in 100% of patients receiving more than 300 U factor VIII/kg b.w./month, in 88% of patients receiving 100 to 300 U factor VIII/kg b.w./month, and in 60% of patients receiving less than 100 U/kg b.w./month. 13 out of all 16 patients (81%) treated with non-virus-inactivated concentrates before 1985 were positive for anti-HCV. In contrast, all patients treated with virus inactivated concentrates were negative for anti-HCV. Elevated aminotransferases were frequently found in 8 out of 13 patients (62%) positive for anti-HCV, but only in 3 out of 11 patients (27%) negative for anti-HCV. The risk of developing chronic hepatitis was about 2.5-fold higher in patients positive for hepatitis C-antibodies than in patients negative for hepatitis C-antibodies.

Adolescent↗
PubMed1991

[Early summer meningoencephalitis vaccination, a preventive medicine measure with high acceptance in Austria].

The vaccination against Tick-borne encephalitis (TBE) was accepted by the Austrian population on a broad scale. Of the estimated 5 million Austrians at risk of TBE, as of 1987 only 1.7 million were unvaccinated. From the very small number of TBE cases despite vaccination we were able to calculate a protection rate of 95% after 2 vaccinations and of 99% after 3 or more vaccinations. Since 1984 as a consequence of the vaccination campaign a steady decline of TBE could be observed in Austria. More than 10 years ago improved procedures enabled the production of a highly purified vaccine, thus reducing the number of side effects to a minimum. We here present data from 2067 vaccinees who reported on eventual side reactions by means of a questionnaire. The reactions reported did not exceed those which could be expected after application of a placebo vaccine. Due to high immunogenicity of the vaccine a booster effect can be achieved even some years after a missed vaccination, precluding the necessity of beginning a new series.

Antibodies, Viral↗
PubMed1990

[Testing for hepatitis C].

Over the past 10 years, 12,146 cases of hepatitis were diagnosed in the Virology Department of Vienna University. 30.3% were hepatitis A, 39.2% hepatitis B, 3.0% cytomegalovirus and 1.5% Epstein-Barr virus infections. The remaining 25.8% were diagnosed as non-A, non-B hepatitis (NANB). Therefrom, a sample of 167 sera from acute and 78 from chronic hepatitis NANB were tested for hepatitis C. 9.6% of the acute and 44.9% of the chronic cases were positive. We conclude from these data that about 12% of all hepatitis cases in Austria are caused by the hepatitis C virus. In addition, risk groups for hepatitis C were tested. The highest prevalence (80%) was found in drug addicts. Polytransfused (organ transplanted) patients had antibodies in 44.8% of cases. Of 78 dialysis patients, 7 were positive but nearly all positives came from one single dialysis unit, thus indicating a prevalence of 30% there.

Adult↗
PubMed1990

Safety and immunogenicity of an inactivated hepatitis A candidate vaccine in healthy adult volunteers.

The reactogenicity and immunogenicity of a formaldehyde-inactivated hepatitis A vaccine have been investigated. Three different dose levels of vaccine (180, 360 and 720 ELISA units) were administered to healthy volunteers according to a 0, 1, 2 and 12 month schedule. The vaccine was safe and well tolerated. Reactions observed following vaccination were essentially mild and were not dependent upon the quantity of antigen administered. All subjects had measurable titres of anti-HAV antibodies after the full vaccination course; the immune response to the vaccine was dose-related. Antibody titres in vaccinees at month 13 were between 60- and 190-fold higher than those observed in a group of subjects given anti-HAV immunoglobulin.

Adolescent↗
PubMed1990

Interindividual comparability of blood glucose alterations after meals of complex carbohydrates.

Young male and female probands underwent an DGTT (oral glucose tolerance test) using a glucose load of 1 g/kg b.wt. The alterations in blood glucose levels were checked and plotted by a Biostator. A week later groups of those probands were fed an isocaloric meal of complex CH, namely either potatoes, noodles or white bread. The resulting BG curves were also checked by a Biostator. It turned out that: 1. the shapes of the BG curves after glucose load were not interindividually comparable. 2. there was neither a similarity of the shapes of the BG curves within the groups after any of the different CH levels. 3. But if one compares the shape of the BG curves after glucose load and after a meal of any of the complex CH of one and the same person, there is a striking similarity in those curve shapes. The differences between them lie just in the mostly lower BG values of the curves after CH meals compared with those after glucose load. 4. Therefore the resulting graph of both of those curves is in all observed cases a straight line with a probability better than 0.001, called OGTT-calibrating resulting graph.

Adult↗
PubMed1990

Relevance of hepatitis B DNA detection in patient's serum.

Detection of HBV-DNA showed a satisfactory sensitivity (6 pg/ml) and high specificity: 15 patients with hepatitis A, 6 with CMV, 7 with EBV infection, 81 with hepatitis NANB as well as 174 persons with isolated HBc antibodies and 9 hepatitis B vaccinees gave negative results. However, out of 118 persons with a history of hepatitis B (HBs and HBc antibodies positive), one repeatedly had a positive result. We followed 58 patients with chronic hepatitis B, 25 healthy antigen carries, and 16 HBV-infected dialysis patients over an extended period with multiple blood sampling. Most of those patients showed changes of detectability of HBV-DNA. Typically, periods with positive DNA tests were followed by intervals with negative tests which could last for up to a few years. 75% of dialysis patients were positive in all sera available, while 48% of healthy antigen carriers were consistently negative. Additionally, 9 patients with a history of recent hepatitis B and a positive HBs antibody test as well as 4 patients with simultaneous infection by A and B were tested for HBV-DNA. In none of these two groups, a variation from the pattern usually found in hepatitis B was established. A case of intrauterine infection with hepatitis B virus is reported. Because the blood of the mother was free from HBV-DNA and HBe antigen at delivery and because the hepatitis B immunoglobulin prophylaxis failed in the child who developed HBs antigen very soon after delivery, it has been concluded that the child was infected in utero. The highest values of HBV-DNA determined quantitatively were found in dialysis patients which explains the high risk of acquiring hepatitis B in the dialysis unit. The results from earlier studies on the prognostic relevance of HBV-DNA and the risk of medical personnel as a source of infection with hepatitis B are discussed briefly.

Chronic Disease↗
PubMed1990

[Fast frequency electroretinogram differentiates ocular hypertension].

On the basis of the 30 Hz responses it was possible to divide the patients (total 38 eyes) into two groups. The PERGs of one group (abnormal OHT) resembled responses of typical glaucomatous eyes, with greatly diminished or abolished 30 Hz amplitudes. The PERGs of the other group (normal OHT) were indistinguishable from those of normal eyes.

Diagnosis, Differential↗
PubMed1990

[A new laser scan system for video ophthalmoscopy. Initial clinical experiences also in relation to digital image processing].

The clinical advantages of a scanning laser ophthalmoscope (SLO) and video imaging of fundus pictures are described. Image quality (contrast, depth of field) and imaging possibilities (confocal stop) are assessed. Imaging with different lasers (argon, He-Ne) and changes in imaging rendered possible by confocal alignment of the imaging optics are discussed. Hard copies from video images are still of inferior quality compared to fundus photographs. Methods of direct processing and retrieval of digitally stored SLO video fundus images are illustrated by examples. Modifications for a definitive laser scanning system - in regard to the field of view and the quality of hard copies - are proposed.

Computer Systems↗
PubMed1990

Isolation of (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine, the characteristic structural element of cyclosporins, from a blocked mutant of Tolypocladium inflatum.

By mutagenic treatment of a strain of Tolypocladium inflatum, a cyclosporin non-producing mutant was obtained which accumulated the characteristic building unit of cyclosporins, (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine (abbreviation Bmt; systematic name: (2S,3R,4R,6E)-2-amino-3-hydroxy-4-methyl-6-octenoic acid) in free form. The isolation from a culture filtrate was performed by extraction, chromatographic separation and final crystallization from methanol - water. The structure and stereochemistry of this amino acid was determined by chemical transformation and correlation to dihydro-MeBmt, with known chirality [(2S,3R,4R)-3-hydroxy-4-methyl-2-methylamino-octanoic acid], obtained by hydrolysis of dihydrocyclosporin A.

Chemical Phenomena↗
PubMed1990

[Diagnosis and epidemiology of hepatitis C].

After years of unsuccessful attempts to isolate the causative agent of hepatitis non-A-non-B this has recently been accomplished. The nucleic acid of a virus, now called hepatitis C, was cloned which formed the basis of a diagnostic ELISA. In this test antibodies against a non-structural protein of the virus can be detected. These antibodies are not actually protective but rather indicate virus activity. The first generation test is hampered by some unspecificity but mostly by the fact that seroconversions are detected very late, sometimes up to 6 months after infection. However by including some more antigens in the ELISA of the second generation this problem will hopefully be overcome. Hepatitis C virus (HCV) antibodies could be found in up to 90% of patients with posttransfusion hepatitis. But also about 75% of patients with sporadic (cryptogenetic) hepatitis, were positive for HCV. Beside multiple blood transfusions (0.7% of blood donors in Austria are infected) other risk factors for HCV are needle sharing by i.v. drug users and treatment for hemophilia, because of HCV is not inactivated during the preparation of antihemophilic plasma. A virus inactivating procedure is therefore carried out in modern preparations. A high percentage of hemodialysis patients are also infected. However, important differences (0 to 30%) were found between different dialysis units. Other investigations revealed that the HCV risk for medical personnel is not extremely high, perhaps only twice that of the normal population. Sexual transmission of the virus seems to be possible but not of practical importance. Although the majority of hepatitis cases which earlier were classified as non-A-non-B, can now be diagnosed as hepatitis C, the possible existence of one more hepatitis virus cannot be excluded.

Blood Transfusion↗
PubMed1990

[Quantitative two-dimensional echocardiography. Study results in patients with cystic fibrosis].

15 patients with cystic fibrosis aged 8-19 years were graduated into 3 stages of the cor pulmonale dependent on results of an examination with the microcatheter: stage 0:6, stage I: 4 and stage II: 5 patients. These patients were studied in the period from April 1987 to January 1988 echocardiographically. With this size and contractility of the right ventricle were especially considered. The end-diastolic and end-systolic area of the right ventricle could be measured in the apical 4-chamber-view in 14 of the altogether 15 patients and out of this the fractional area-shortening could be calculated. The end-diastolic area of the right ventricle in the patients with stage 0 was on an average 11.4 cm2/m2 body surface bs (8.7-13.5), in stage I 11.2 cm2/m2 bs (9.2-13.5), and in stage II 9.7 cm2/m2 bs (9.0-10.8). The end-systolic area of the right ventricle in stage 0: 7.2 cm2/m2 bs (6.8-8.4), stage I: 7.1 cm2/m2 bs (6.0-8.5), and stage II: 8.02 cm2/m2 bs (6.4-10.1). The results we found don't differ significantly in the 3 groups. Contrary to this fractional area-shortening of the right ventricle shows a falling tendency: stage 0.35.2% (22-49), stage I 32% (7-56), stage II 17.2% (4-38) with an increasing part of patients with a value under 28% (stage 0:1 patients, stage I 2 patients, stage II 3 patients). Contractility and pump-efficiency of the left ventricle were calculated in the apical 4-chamber-view according of the area-length-method. The findings don't show an increasing size of the right ventricle in the sense of a cor pulmonale but a decreasing contractility and pump-efficiency of the right ventricle as expressions of a cardial manifestation of the basic illness in the sense fo a symptomatic cardiomyopathy. A disturbance of the contractility of the left ventricle could be seen in 7 of the 15 patients (47%).

Adolescent↗