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Biomedical subjects

W Arnold

Publications and source records attributed to W Arnold.

At least 235 records · Page 13Linked to original sources
PubMed1988

Clinical, genetic, and epidemiological factors in neural tube defects.

We examined clinical, genetic, and epidemiologic factors among 512 probands with nonsyndromal neural tube defects (NTDs). Data were analyzed after grouping the probands in four different ways with respect to pathological features and putative pathogenic mechanisms. Apparently unrelated congenital anomalies occurred more frequently among probands with craniorachischisis (62%), encephalocele (30%), or multiple NTDs (25%) than among probands with anencephaly (14.7%) or spina bifida (10.1%) (P much less than .0001). Unrelated congenital anomalies occurred less often among probands with low spina bifida (6.7%) than among probands with high spina bifida (19.5%). NTDs were seen in 7.8% of the siblings of probands with high spina bifida but in only 0.7% of the siblings of probands with low spina bifida, in 2.2% of the siblings of anencephalic probands, and in none of the siblings of probands with craniorachischisis, encephalocele, or multiple NTDS (P less than .001). In all 16 families in which two siblings had NTDs, both had either defects of the type associated with abnormal primary neurulation or defects of the type associated with abnormal canalization. High spina bifida and multiple NTDs were found more frequently than expected among the Sikh probands (P less than .02). The frequency of non-NTD congenital anomalies was higher among siblings of Sikh probands (8.8%) than among siblings of other probands (2.4%) (P less than .05). This excess was due to the occurrence of hydrocephalus without spina bifida in four of 68 siblings of Sikh probands.

Adult↗
PubMed1988

[Effect of a rotating sound source on postrotatory nystagmus].

In 10 healthy individuals the influence of a rotating sound source (loudspeaker, narrow band noise 500 Hz, 70 dB SPL, 120 degrees/sec.) on the postrotatory nystagmus was investigated. If the loudspeaker was rotating in the opposite direction of the fast postrotatory nystagmus component, the duration and intensity of the postrotatory nystagmus was amplified by about 30%. If the loudspeaker was rotating in the direction of the fast postrotatory nystagmus component, no changes were seen.

Adult↗
PubMed1988

[Current value of mediastinoscopy].

Between 1976 and 1985 a total of 367 mediastinoscopies were performed in the ENT Clinic, Kantonsspital of Lucerne, Switzerland. Between 1976 and 1981 and average of 50 cases were carried out annually, but the introduction of CT-scanning has provoked a considerable fall in their number. Although mediastinoscopy involves few risks, with a morbidity of 0.8% and a mortality of 0% it has increasingly been replaced by CT-scanning as the sensitivity of both procedures is comparable. The only remaining indication for mediastinoscopy is when lymph node biopsy is necessary in systemic diseases with primary mediastinal lesions.

Adolescent↗
PubMed1988

[Sequential animal experimental determination of optimal dosages for combinations of cytostatics using a reduced number of experimental animals (vepeside/ifosfamide combination)].

Complete groups of animals can be economized by application of the Box-Wilson-method to experimental determination of an optimal dosage for a drug combination. It is possible to minimize the number of controls additionally by means of successive cumulation of the number of controls additionally by means of successive cumulation of control-dates of interest over the single experiments of the series required and to improve the estimation of the reference parameter. An example is given to explain the procedure of evaluation of an optimal dosage for the two-drug combination VP16/IFX. Side effects are taken into consideration. An advantage is proved for the combination against the single substances.

Animals↗
PubMed1987

Tight linkage of glnA and a putative regulatory gene in Rhizobium leguminosarum.

Rhizobium leguminosarum, biovar viceae, strain RCC1001 contains two glutamine synthetase activities, GSI and GSII. We report here the identification of glnA, the structural gene for GSI. A 2 kb fragment of DNA was shown to complement the Gln- phenotype of Klebsiella pneumoniae glnA mutant strains. DNA sequence analysis revealed an open reading frame (ORF) of 469 codons specifying a polypeptide of 52,040 daltons. Its deduced amino acid sequence was found to be highly homologous to other glutamine synthetase sequences. This ORF was expressed in Escherichia coli minicells and the corresponding polypeptide reacted with an antiserum raised against GSI. Upstream of glnA we found an ORF of 111 codons (ORF111) preceded by the consensus sequence for an ntrA-dependent promoter. Minicells experiments showed a protein band, with a molecular weight in good agreement with that (10,469) deduced from the nucleotide sequence. On the basis of homology studies we discuss the possibility that the product of ORF111 is equivalent to the PII protein of E. coli and plays a similar role in regulation of nitrogen metabolism.

DNA Restriction Enzymes↗
PubMed1987

[Meniscus imaging in MR tomography using surface coils. Anatomy, areas of degeneration, laceration formation].

High resolution MR imaging using surface coils and thin-section techniques provides specific information when evaluating meniscal diseases. Extension and localisation of meniscal tears can be demonstrated as well as meniscal attachment areas. Diagnosis of degenerative changes is possible. We examined 7 healthy volunteers and 58 patients with suspected knee injuries. This study was done to discuss the use of MRI in the evaluation of meniscal diseases.

Arthrography↗
PubMed1987

Rhizobium meliloti nifN (fixF) gene is part of an operon regulated by a nifA-dependent promoter and codes for a polypeptide homologous to the nifK gene product.

An essential gene for symbiotic nitrogen fixation (fixF) is located near the common nodulation region of Rhizobium meliloti. A DNA fragment carrying fixF was characterized by hybridization with Klebsiella pneumoniae nif DNA and by nucleotide sequence analysis. The fixF gene was found to be related to K. pneumoniae nifN and was therefore renamed as the R. meliloti nifN gene. Upstream of the nifN coding region a second open reading frame was identified coding for a putative polypeptide of 110 amino acids (ORF110). By fragment-specific Tn5 mutagenesis it was shown that the nifN gene and ORF110 form an operon. The control region of this operon contains a nif promoter and also the putative nifA-binding sequence. For the deduced amino acid sequence of the nifN gene product a striking homology to the R. meliloti nifK protein was found. One cysteine residue and its adjacent amino acid sequence, which are highly conserved in the R. meliloti nifK, R. meliloti nifN, and K. pneumoniae nifN proteins, may play a role in binding the FeMo cofactor.

Amino Acid Sequence↗
PubMed1987

Detection of hepatitis B virus markers in sera of asymptomatic hepatitis B surface antigen carriers with special emphasis to pre-S-encoded proteins.

Sera of asymptomatic hepatitis B surface antigen (HBsAg) carriers were analyzed for the presence of pre-S-encoded proteins. Four individuals with biopsy-proven chronic hepatitis uniformly expressed pre-S1- and pre-S2-encoded proteins. Individuals who had histologically normal or largely normal livers were heterogeneous with respect to expression of pre-S-encoded proteins. This heterogeneous expression of pre-S-encoded proteins occurred most likely due to difference in serum HBsAg concentration. Alternatively differences in pre-S gene expression need to be considered. Clinically the study indicates that expression of pre-S domains in serum is unrelated to viremia or chronic liver disease.

Carrier State↗
PubMed1987

Radioimmunological hair analysis for narcotics and substitutes.

In recent years it has become possible to detect organic pharmaceuticals and poisons in a few milligrams of hair, using radioimmunological methods. Some methods are specific for individual compounds, others for groups of compounds. This is of great importance inter alia for forensic purposes, especially in cases of drug abuse. With the help of such hair analysis it is possible to trace the drug career of an addicted person for up to one year, and in certain cases for a longer period. Frequently, the results provide information on events in the rather distant past. This can be of considerable anamnestic and forensic importance.

Adult↗
PubMed1987

Possibilities of immunohistochemical investigation on human temporal bone.

After preliminary studies on human tonsillar tissue, lymph node tissue, or tissue from the appendix, it could be shown that after a fixation in Bouin solution or in sublimate-formaldehyde solution and subsequent embedding of the tissue in paraffinwax, the structure of the immunoglobulins present in the tissue remains intact. Even after long-term decalcification of the fixed tissue in EDTA, its structure does not alter and the immunoglobulins can be detected in high dilution either by the direct immunofluorescence method or with peroxidase-antiperoxidase. Human temporal bones from healthy individuals were fixed in Bouin solution or in sublimate-formaldehyde solution and incubated for sufficient time in EDTA decalcification solution until they were radiologically free of calcium. After embedding in paraffinwax or Paraplast, the immunoglobulins of the middle ear mucosa could be identified with the immunohistochemical methods described above. For the first time, localized immunoglobulins including the secretory component in the endolymphatic sac could also be demonstrated. The method is so sensitive that the binding of antibodies from the serum of patients with possibly immunopathological inner ear conditions can be detected by means of the indirect immunofluorescence test. Furthermore, other immunohistochemical assay methods can also be carried out with these methods (e.g. neuropeptide detection.

Decalcification Technique↗
PubMed1987

Myelination of the human spiral ganglion.

Temporal bones from adolescents and adults with healthy ears were fixed immediately after death with glutaraldehyde and processed for the electron microscopic examination without decalcification. No myelinated ganglion cells could be identified by light microscopy. Electron microscopically, we did not find any myelinated ganglion cells in the region of the spiral ganglion of 4 neonatal infants. In the temporal bones of 6 young adults (aged between 18 and 25 years), 0.3% to 0.5% of all ganglion cells were enveloped in a loose myelin coat. The spiral ganglion of two temporal bones from elderly persons (aged 61 and 63 years) contained up to 2% ganglion cells with a thin but regular myelination (up to five myelin layers). Large ganglion cells (type I) are situated in the centre of the ganglion cell complex with a palisade arrangement. Small ganglion cells (type II) are found almost exclusively in the periphery of the ganglion cell complex. There is no difference in the frequency of myelination of large and small ganglion cells. The small ganglion cells amount to about 3% of the entire ganglion cell population. Since myelination is to be observed more frequently in elderly people than in adolescents or neonates, it is possible that myelination of ganglion cells of the spiral ganglion does not play an important physiological role in humans.

Adolescent↗
PubMed1987

[Detection of measles and rubella-specific antigens in the endochondral ossification zone in otosclerosis].

Paramyxoviruses have been described in the osteoclasts in Paget's disease and it has been suggested that the disease was caused by this virus. There is considerable similarity of the histological features of active otosclerosis and Paget's disease and the probable presence of viral antigens in the otosclerotic footplate of the stapes of 15 patients has been investigated by means of immunohistochemical methods. The active otosclerotic lesions of all 15 patients studied displayed a high concentration of antibodies of the IgG-class which was less pronounced in the cytoplasm of the cells of the adjacent enchondral layer. Using polyclonal antibodies against measles and rubella viruses, both antigens could be shown expressed by the chondrocytes of the enchondral layer and by occasional osteocytes and osteoclasts of the otosclerotic lesion. IgG antibodies or viral antigens were absent in the normal bone of the stapes specimens. The interpretation and significance of these findings is discussed, with particular reference to the pathogenesis of otosclerosis.

Adult↗
PubMed1987

[Heavy water (D20) inhibits growth of human xenotransplanted oropharyngeal cancers. An animal experiment study in nude mice].

The large mass ratio of D to H, 2 to 1, gives rise to multiple effects in living organisms, when D is administered as heavy water (D2O). Deuterium at high concentration interferes with cell division and depresses the uptake of DNA-precursors in mammalian cells (Katz et al., 1970). However, the effects of D2O on the organism disappear after cessation of deuteration of the body water. Mammals do not survive more than 35% of D2O substitution for normal water in their body fluids for long periods of time. However, mice drinking 30% D2O have a normal life span and normal body weight (Katz et al., 1970; Hodel et al., 1982). Heavy water also exerts antineoplastic effects. We demonstrated that moderate body deuteration combined with a cytostatic drug significantly increases the survival time of mice bearing transplantable murine neoplasms (Laissue et al., 1982). Hitherto, it is not known whether heavy water affects human neoplasms in the same way. Therefore, we have studied human squamous cell carcinomas of the oropharyngeal region which were xenografted in nude mice. A moderate deuteration of body water of the mice (less than or equal to 20 atom %) drinking 30% D2O, inhibited the tumour growth markedly by a factor of 0.4 to 0.5 compared to the growth of the same tumours in control animals drinking tap water. This effect of D2O seems to be directly proportional to the grade of malignancy of the carcinomas. Histologically, no differences were detectable between the original carcinomas and the tumour grafts in animals with and without D2O.

Animals↗
PubMed1987

Characterization of human mammary normal and neoplastic cells grown in culture.

The paper presented here describes cultivation and characterization of human mammary normal (NMC) and neoplastic (BO) cells. Characteristics: growth rate, colony growth in soft agar, nuclear overlaps, induction of multinucleation by Cytochalasin B and transplantation in vivo were compared between NMC- and BO-cells. Normal (NMC) cells are characterized by a slow growth rate (cell doubling time less than 70 hours), no growth in soft agar, no induction of uncontrolled nuclear division and no development of tumors after transplantation of cells in nude mice in vivo. The two cell types do not differ with respect to the nuclear overlapping ratio. In contrast, neoplastic (BO) cells showed a lower doubling time (less than 20 hours), colony growth in soft agar (greater than 20 colonies/30,000 cells), induction of multinucleation by Cytochalasin B (greater than or equal to 3 nuclei/cell), and tumors in nude mice were observed. Both cell types were recommended as an in-vitro model for screening antineoplastic agents.

Animals↗
PubMed1987

[Binding of serum immunoglobulins to human inner ear tissue in inner ear hearing loss: methodologic limits].

The immunopathological processes possibly involved in cryptogenic sensorineural hearing loss were investigated. In a pilot study the sera from 66 patients were tested by the indirect immunofluorescence technique for immunoglobulins which bind to normal human inner ear tissue. The reaction was positive in two thirds of all patients with sudden hearing loss, especially bilateral. This was mostly for IgG, and to the organ of Corti. Others have found that Corti's organ showed marked degenerative changes in cases of sudden hearing loss, examined by histology. The reaction was positive in half of the patients with progressive sensorineural hearing loss. It was noticeable that positive reactions for IgA were twice as frequent in sera of patients with progressive hearing loss than in those with sudden deafness. In a control study, the sera of ten patients were tested in parallel by the same method on histological sections of inner ears taken from four individuals. Similar results were found for the sera of two patients only. The sera of the remaining eight patients revealed very inconsistent reaction patterns. These preliminary results may indicate that temporary or permanent humoral (auto) immune mechanisms could have occurred in certain inner ear diseases. So far however reliable diagnostic methods have not been established, and not enough patients have been followed up.

Adolescent↗