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Biomedical subjects

C Kunz

Publications and source records attributed to C Kunz.

At least 19 recordsLinked to original sources
PubMed1992

[Endangering of the Liechtenstein population by the early-summer meningoencephalitis virus].

There have been a few severe cases of tick-borne encephalitis in Liechtenstein during the last 20 years. To form a better idea of the risk of infection and the potential benefit of vaccination, a total of 311 sera from different cohorts were investigated for antibodies to tick-borne encephalitis. The mean seroprevalence found was 3.6% and was not higher even in persons who were active in professional forestry. The antibodies measured derived in all groups mainly from previous vaccination and in only 2 cases (0.6%) from natural infection. It is concluded that the risk of TbE infection in Liechtenstein is very low. Therefore, a reduction in cases would probably be achieved only by mass vaccination.

Antibodies, Viral↗
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↗
PubMed1992

Cloning and expression of a chitinase gene from the hyperparasitic fungus Aphanocladium album.

Recombinant clones from a cDNA library of an Aphanocladium album chitinase-overproducing mutant strain were isolated by screening with antiserum against a 39 kDa chitinase purified from this hyperparasitic fungus. Analysis of the isolated positive clones indicated that most of them carried the same cDNA. A cDNA from this group was used as a hybridization probe to isolate an 8 kb DNA fragment from a genomic library of the wild-type strain. The chitinase 1 gene was mapped to this fragment by two independent approaches. Its partial DNA sequence was in perfect agreement with an amino-terminal peptide sequence obtained by sequencing 23 amino acids of the 39 kDa chitinase. Its transfer in Fusarium oxysporum resulted in a transformant producing both a protein of about 39 kDa that cross-reacted with the chitinase antiserum and a chitinase activity that was inhibited by the same antiserum. Northern blot analysis indicates that the cloned chitinase gene was subject to catabolite repression and appeared inducible by chitin.

Amino Acid Sequence↗
PubMed1992

Molecular epidemiology of tick-borne encephalitis virus: cross-protection between European and Far Eastern subtypes.

Tick-borne encephalitis virus isolates from widely separated geographic regions of the USSR, six isolates from Hungary and one from France were compared with the European and Far Eastern prototype viruses. Peptide mapping by limited proteolysis yielded similar patterns for five selected isolates from the USSR. All isolates from Hungary and France exhibited the same reactivity pattern with a panel of 16 protein E-specific monoclonal antibodies, whereas 10 out of 12 isolates from the Soviet Union showed minor differences at certain epitopes. However, no correlation between geographic origin of the isolates and their antigenic structure was observed. No statistically significant difference in the degree of protection was detected when mice were immunized with the European prototype vaccine and challenged with three selected Asian isolates and one from the European part of the USSR.

Animals↗
PubMed1992

Simultaneous vaccination against hepatitis A and B: results of a controlled study.

Hepatitis A and hepatitis B are endemic in many countries and must be considered as serious health risks for large parts of the world population. Simultaneous or combined vaccination against these two diseases would therefore be most advantageous. In order to investigate possible interactions between these vaccines with respect to their tolerability and immunogenicity, we conducted a randomized prospective study comparing single and simultaneous administration of the two vaccines. Three groups of healthy volunteers, each with 55 persons, were included in the study. All were negative for hepatitis A and hepatitis B markers and had normal serum liver enzyme values. Group I received hepatitis A vaccine (720 ELISA units) into the left deltoid muscle, group II received hepatitis B vaccine (20 micrograms) into the right deltoid muscle and group III received hepatitis A vaccine into the left, and hepatitis B vaccine into the right deltoid muscle. Three doses of the vaccines were administered at 0, 1 and 6 months. Local and systemic reactions were monitored by means of questionnaires. Blood samples for determination of antibody to hepatitis A virus (anti-HAV) and antibody to hepatitis B surface antigen (anti-HBs) and of serum SGOT and SGPT levels were drawn at months 0, 1, 2, 6 and 7. There were no serious general and only mild local reactions. The mean serum SGOT and SGPT values remained in the normal range in all groups. The seroconversion rates and mean geometric titres of the anti-HAV and anti-HBs antibodies were similar when the vaccines were administered separately or simultaneously. There were no significant differences between the compared groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Low renal net acid excretion, high calciuria and biochemical signs of sodium deficiency in low-birth-weight infants fed a new low-phosphorus formula.

In 11 infants (birth weight greater than 1800 g) fed a new type of humanized formula with a low phosphorus (P) content (calcium (Ca) 11 mmol/l, P 7.2 mmol/l, sodium (Na) 8.3 mmol/l) biochemical parameters of blood, serum and urine were determined. In nine boys Ca and P balances were evaluated also. Renal net acid excretion was low (0.85 mmol/kg/day). Mean concentrations of P and Ca in urine were 0.34 mmol/kg/day (10.5 mg/kg/day) and 0.1 mmol/kg/day (4 mg/kg/day), respectively. In four infants, Ca concentration in urine was, however, greater than 0.15 mmol/kg/day) (6 mg/kg/day). In infants with birth weights greater than 1800 g fed the new, low-P formula, the low renal net acid excretion, the normal P and the high Ca concentrations in urine were comparable to term infants fed human milk. The high calciuria in several infants may be normal physiologic values. However, it remains to be established that the urinary solubility product of infants fed the new, low-P formula is in the same range as those for infants fed human milk. Unexpectedly, low urinary Na excretion (0.26 mmol/kg/day) and increased urinary excretion of aldosterone-18-glucuronide indicated biochemical evidence of Na deficiency secondary to low Na intake and a high weight gain. If the new, low-P formula is to be fed to infants with a birth weight as low as 1800 g. Na content should be higher than in mature human milk because of the often relatively higher weight gain.

Acid-Base Equilibrium↗
PubMed1992

Re-evaluation of the whey protein/casein ratio of human milk.

Total casein subunits as well as whey proteins were quantitated in human milk samples during lactation. Two independent methods were used: precipitation at pH 4.3 in the presence of Ca2+ followed by Kjeldahl analysis and polyacrylamide gradient gel electrophoresis (PAGGE) followed by densitometric scanning. Both methods yielded similar results: casein synthesis is low or absent in early lactation, then increases rapidly and subsequently decreases. The concentration of whey proteins decreases from early lactation and continues to fall. These changes result in a whey protein/casein ratio of about 90:10 in early lactation, 60:40 in mature milk and 50:50 in late lactation. These observations indicate that the synthesis and/or secretion of caseins and whey proteins is regulated by different mechanisms. In addition, the relative proportion of the different beta- and kappa-casein subunits was found to vary throughout lactation.

Caseins↗
PubMed1992

Equine keratoma.

Explore the source record for details and available documents.

Animals↗
PubMed1992

[Biomechanics of the carpus--functional anatomy and movement analysis of the carpal bones].

The often unsatisfactory outcome of attempts to reconstruct ligaments and perform partial arthrodeses of the wrist bones has prompted us to investigate the kinematic behavior of the proximal row of carpal bones in their immediate environment. The movements of the individual bones were observed on fresh autopsy specimens before they were dissected to study the exact location of the interconnecting ligaments. Finally, a special model of epoxy resin was made in which the exact form of the joint surfaces (cartilage surfaces) was maintained. The ligaments were simulated by means of stout threads and, according to the observations recorded in the previous study, attached to the model bones. In this manner a working model resulted that not only proved the correct positioning of the ligaments, but also enabled their function in controlling the movements of the bones during dorsal-palmar flexion and radial-ulnar abduction of the wrist to be established. It was seen that movement of the proximal row of carpal bones is caused primarily by the orientation of the adjoining articular surfaces and limited by the ligaments. Therefore, it is of paramount importance that the friction at the joint surfaces remains as low as possible. If the friction increases, the "floating" bones can no longer slide under load and movement of the hand becomes limited.

Biomechanical Phenomena↗
PubMed1991

Respiratory tract infections due to different rhinovirus serotypes and the influence of maternal antibodies on the clinical expression of the disease in infants.

Rhinoviruses were isolated from nasopharyngeal secretions of 49 children hospitalized because of severe respiratory tract infection. The isolates were typed using 90 type-specific antisera. No obvious relation between certain serotypes and the severity of illness was found. Serum samples were drawn from all children simultaneously with the nasopharyngeal secretions and screened for the presence of type-specific neutralizing antibodies. Children aged 1 week to 6 months had higher neutralizing antibody titers and revealed a lower degree of morbidity than older children. The decline of neutralizing serum antibodies with increasing age was correlated with a higher incidence of severe disease in those aged 7-12 months. Nevertheless, also in this age group children with mild clinical courses of disease were observed despite a low concentration or an absence of neutralizing serum antibodies. This indicates that not only neutralizing serum antibodies, but other factors also influence the clinical expression of RHV-induced disease.

Antibodies, Viral↗
PubMed1991

Sequence of the genes encoding the structural proteins of the low-virulence tick-borne flaviviruses Langat TP21 and Yelantsev.

The structural protein coding regions of the genomes of Langat virus (strain TP21) and Yelantsev virus, which was originally described to be a low virulence natural isolate of tick-borne encephalitis virus, were cloned and sequenced. These viruses had both been used as experimental live vaccines against tick-borne encephalitis in Czechoslovakia and Russia, respectively. Peptide mapping and monoclonal antibody binding experiments yielded identical reaction patterns for Langat virus and Yelantsev virus which were distinct, however, from the pattern obtained with tick-borne encephalitis virus. Sequence analysis confirmed this distinctiveness and proved that the vaccine strain Yelantsev was also Langat virus. The envelope protein E of both viruses exhibits an 88% amino acid sequence homology with that of tick-borne encephalitis virus. Assessment of the antigenic reactivity and sequence comparison with the E protein of tick-borne encephalitis virus revealed several differences affecting epitopes involved in virus neutralization. These observations suggest that Langat-like virus-based vaccines may not represent the most effective means to achieve protection against tick-borne encephalitis virus.

Amino Acid Sequence↗
PubMed1991

The relationship between the flaviviruses Skalica and Langat as revealed by monoclonal antibodies, peptide mapping and RNA sequence analysis.

The flavivirus Skalica was isolated from a bank vole in Czechoslovakia in 1976. It can be serologically distinguished from prototype strains of tick-borne encephalitis (TBE) virus and has a decreased virulence for adult mice. We have further defined the relationship of Skalica virus to other members of the TBE serocomplex (TBE European and Far Eastern subtypes, Langat and louping ill virus) by using a panel of 22 monoclonal antibodies, peptide mapping and RNA sequence analyses. By these criteria Skalica virus proved to be distinct from TBE virus and to be very closely related to Langat virus, differing by only two bases among a total of 416 nucleotides compared. The sequence of 22% of the Langat genome was determined and the encoded amino acid sequences were derived. Comparison of these with the corresponding amino acid sequences of TBE virus revealed a similarity of 85%, as opposed to 93% similarity between the European and Far Eastern subtypes of TBE virus.

Amino Acid Sequence↗
PubMed1991

Fusion activity of flaviviruses: comparison of mature and immature (prM-containing) tick-borne encephalitis virions.

The fusion activity of flaviviruses [tick-borne encephalitis (TBE) virus and Japanese encephalitis virus] was assessed by inducing fusion from without of C6/36 mosquito cells with purified virus preparations. Membrane fusion and polykaryocyte formation was observed only after incubating the viruses at acidic pH. Two groups of monoclonal antibodies reacting with distinct non-overlapping antigenic domains on the TBE virus protein E inhibited fusion from without. One of these domains contains the most highly conserved and putative fusion-active sequence of the flavivirus protein E. Of five TBE virus monoclonal antibody escape mutants, each defined by a single amino acid substitution in the envelope protein E, one revealed a reduced fusion activity and another one a lower pH threshold. TBE virus grown in the presence of ammonium chloride as well as Langat virus purified from the supernatant of infected chick embryo cells contained the precursor of protein M (prM) rather than M itself. These 'immature' virions did not cause fusion from without, suggesting that the proteolytic processing of prM may be necessary for the generation of fusion-competent virions.

Aedes↗
PubMed1991

Detection of varicella-zoster virus DNA by polymerase chain reaction in the cerebrospinal fluid of patients suffering from neurological complications associated with chicken pox or herpes zoster.

The polymerase chain reaction (PCR) was used to detect varicella-zoster virus (VZV) DNA in the cerebrospinal fluid of patients with VZV infection associated with neurological symptoms. Positive results were obtained in three of five children with post-chicken pox cerebellitis and in seven of seven herpes zoster patients with neurological symptoms. The PCR thus provides a useful tool for the early diagnosis of VZV-associated neurological disease.

Chickenpox↗
PubMed1991

The flavivirus envelope protein E: isolation of a soluble form from tick-borne encephalitis virus and its crystallization.

By the use of limited trypsin digestion of purified virions, we generated a membrane anchor-free and crystallizable form of the tick-borne encephalitis virus envelope glycoprotein E. It retained its reactivity with a panel of monoclonal antibodies, and only subtle structural differences from the native protein E were recognized. Treatment with the bifunctional cross-linker dimethylsuberimidate resulted in the formation of a dimer. Crystallization experiments yielded hexagonal rod-shaped crystals suitable for X-ray diffraction analysis.

Amino Acid Sequence↗
PubMed1991

Presence of poly(A) in a flavivirus: significant differences between the 3' noncoding regions of the genomic RNAs of tick-borne encephalitis virus strains.

A poly(A) tail was identified on the 3' end of the prototype tick-borne encephalitis (TBE) virus strain Neudoerfl. This is in contrast to the general lack of poly(A) in the genomic RNAs of mosquito-borne flaviviruses analyzed so far. Analysis of several closely related strains of TBE virus, however, revealed the existence of two different types of 3' noncoding (NC) regions. One type (represented by strain Neudoerfl) is only 114 nucleotides long and carries a 3'-terminal poly(A) structure. This was also found in several TBE virus strains isolated from different geographic regions over a period of almost 30 years. The other type (represented by strain Hypr) is 461 nucleotides long and not polyadenylated. The sequence homology between the two types of TBE virus 3' NC regions terminates at a specific position 81 nucleotides after the stop codon. The second type of 3' NC region more closely resembles the common flavivirus pattern, including the potential for the formation of a 3'-terminal hairpin structure. However, it lacks primary sequence elements that are conserved among other flavivirus genomes.

Animals↗