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Biomedical subjects

T Weber

Publications and source records attributed to T Weber.

At least 181 records · Page 10Linked to original sources
PubMed1997

Analysis of the systemic and intrathecal humoral immune response in progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a subacute viral infection of oligodendrocytes by JC virus occurring almost exclusively in immunocompromised patients. By use of partially purified recombinant VP1 as antigen, the IgG response was analyzed by a quantitative ELISA of paired cerebrospinal fluid (CSF) and serum samples. An intrathecal immune response to VP1, defined as an antibody-specificity index of CSF to serum antibody titers > or =1.5, was found in 76% of PML patients (47/62) but in only 3.2% of controls (5/155) (P < .001). Intra-blood-brain barrier synthesis of VP1-specific IgG antibodies is 76% sensitive and 96.8% specific for the diagnosis of PML. Furthermore, the excellent correlation (r = .985) between the plasma cell count in brain tissue and the humoral intrathecal immune response to VP1 in PML patients suggests a role for B cells in this disorder.

Adolescent↗
PubMed1997

Generating autotetraploid sporophytes and their use in analyzing mutations affecting gametophyte development in the fern Ceratopteris.

The haploid gametophytes of the fern Ceratopteris richardii are autotrophic and develop independently of the diploid sporophyte plant. While haploid genetics is useful for screening and characterizing mutations affecting gametophyte development in Ceratopteris, it is difficult to assess whether a gametophytic mutation is dominant or recessive or to determine allelism by complementation analysis in a haploid organism. This report describes how apospory can be used to produce genetically marked polyploid sporophytes whose gametophyte progeny are heterozygous for mutations affecting sex determination in the gametophyte and a known recessive mutation affecting the phenotype of both the gametophyte and sporophyte. The segregation ratios of wild-type to mutant phenotypes in the gametophyte progeny of polyploid sporophyte plants indicate that all of the mutations examined are recessive. The presence of many multivalents and few univalents in meiotic chromosome preparations of spore mother cells confirm that the sporophyte plants assayed are polyploid. The DNA content of the sperm of their progeny gametophytes was also found to be approximately twice that of sperm from wild-type haploid gametophytes.

Alleles↗
PubMed1997

Neonatal herpes in Denmark 1977-1991.

BACKGROUND: To prevent neonatal herpes, women in labor with genital herpes infection are still delivered by Cesarean section. This policy is currently being debated. The aim of this study was to determine the incidence of neonatal herpes in Denmark and to evaluate the prevention practice. METHODS: All newborns with perinatal herpes in Denmark 1977-1991 were identified from hospital-records. RESULTS: Of 862,298 deliveries 136 possible cases were found but only 30 (22%) fulfilled the criteria for neonatal herpes. The incidence increased from 2.36 to 4.56 per 100,000 live births during 1977-1984 through 1984-1991. Three mothers (10%) had recurrent herpes at delivery, three (10%) had primary herpes, and five (17%) had oral herpes. Seven infants (23%) were delivered by Cesarean section. Nine (30%) only had cutaneous herpes, four (13%) had CNS herpes, nine (30%) had disseminated disease. Six (20%) did not have any sequelae. Four (13%) died. Six (20%) had serious neurological sequelae. Seven (23%) only had cutaneous recurrences. In seven cases (23%) information was insufficient. CONCLUSIONS: During a 15 year period in Denmark only one neonate had serious sequelae following a recognized maternal herpes recurrence. Four infants had a serious infection in spite of Cesarean section. This study does not support a policy of Cesarean section in case of maternal recurrent herpes simplex infection at delivery.

Cesarean Section↗
PubMed1997

Progressive multifocal leukoencephalopathy: molecular biology, pathogenesis and clinical impact.

The human polyomaviruses JC virus (JCV) and BK virus (BKV) have long been known as onco- and neurooncogenic. Interest in their oncogenic potential has reemerged with the discovery of simian virus 40 DNA in human brain tumors including the pituitary as well as in bone tumors and mesotheliomas. The only human disease caused by an infection with the human polyomavirus JCV is progressive multifocal leukoencephalopathy (PML) characterized by a lytic infection of oligodendrocytes with consecutive demyelination. Malignant transformation of cell lines appears to be caused by a complex interaction of the viral large T (tumor) antigen with several transcription factors and tumor suppressor proteins such as p53 and the retinoblastoma protein. PML, once an extremely rare disease, has become much more frequent in the western world owing to the AIDS pandemic. An exceedingly complicated, cell-, tissue- and species-specific pattern of protein-DNA interaction and negative as well as positive feedback regulation by at least a dozen proteins and possibly mutations in the JC viral promoter-enhancer region govern host range and development of PML. The intricate molecular and immunological prerequisites ultimately leading to PML in humans have not yet been completely elucidated.

Animals↗
PubMed1997

The spectrum of transmissible spongiform encephalopathies.

Since the first description by A.M. Jakob and H.G. Creutzfeldt, five human diseases have been identified as transmissible spongiform encephalopathies (TSE). The disease bearing these authors' name, Creutzfeldt-Jakob disease (CJD) occurs sporadically, may be transmitted and has a genetic basis in 10-15% of all cases. Genetic diseases are the Gerstmann-Sträussler-Scheinker syndrome and fatal familial insomnia. The latest form of CJD in humans, variant CJD (vCJD), was first described in 1996 and may be considered as evidence for a link between human TSEs and those in the animal kingdom. The putative agent of all TSEs is a proteinaceous infectious agent or prion. The gene for the physiological isoform of this protein (prion related protein or PrPc)-is encoded on the short arm of chromosome 20 in humans. The role of the physiological isoform of PrPc is unknown. The physiological isoform PrPc is protease-sensitive and thus designated as PrP-sen, while the pathological isoform is protease-resistant and thus called PrP-res. The pathological isoform PrP-res is invariably associated with TSEs and has given rise to the term prion diseases. PrP-sen and PrP-res have an identical amino acid sequence and have identical posttranslational modifications as assessed by currently available methodology but differ in their tertiary and quaternary structure. These structural differences are thought to be propagated by interaction of PrP-res with PrP-sen, appear to be governed by the polymorphism of PrPc and have been shown to be invariably associated with disease. PrP-sen has a high content of alpha-helical structures, PrP-res consists predominantly of beta-pleated sheets. These physicochemical characteristics of PrP-res cause it to behave like amyloid. The neuropathological hallmarks of TSEs or prion diseases are spongiform change, astrocytic gliosis, neuronal loss and PrP-positive plaques. A nucleic acid has never consistently been shown in any TSE. Diagnosis of TSE can be reliably made only postmortem.

Animals↗
PubMed1996

[Local guidelines for delivery with breech presentation. A nation-wide questionnaire].

All 30 Danish obstetric departments have answered a questionnaire focusing on local guidelines for delivery of singleton foetuses in breech presentation at term. Two departments recommended caesarean section to all parturients and ten departments to all primiparae. The criteria for recommendation of vaginal delivery varied, one department used pelvimetry, one did not attempt external version, ten did not permit induction of labour. All departments except two always had a specialist in obstetrics present at the delivery, 24 (of 28 departments) an anaesthetist and 20 a paediatrician. The complexity in criteria and organisation reported is not surprising considering different recommendations in the literature, which means that the guidelines are primarily based on traditions and personal experience.

Breech Presentation↗