PubMed Health⌕ Search

Biomedical subjects

D Rudolph

Publications and source records attributed to D Rudolph.

At least 19 recordsLinked to original sources
PubMed2000

Severe liver degeneration and lack of NF-kappaB activation in NEMO/IKKgamma-deficient mice.

Phosphorylation of IkappaB, an inhibitor of NF-kappaB, is an important step in the activation of the transcription factor NF-kappaB. Phosphorylation is mediated by the IkappaB kinase (IKK) complex, known to contain two catalytic subunits: IKKalpha and IKKbeta. A novel, noncatalytic component of this kinase complex called NEMO (NF-kappaB essential modulator)/IKKgamma was identified recently. We have generated NEMO/IKKgamma-deficient mice by gene targeting. Mutant embryos die at E12.5-E13.0 from severe liver damage due to apoptosis. NEMO/IKKgamma-deficient primary murine embryonic fibroblasts (MEFs) lack detectable NF-kappaB DNA-binding activity in response to TNFalpha, IL-1, LPS, and Poly(IC) and do not show stimulus-dependent IkappaB kinase activity, which correlates with a lack of phosphorylation and degradation of IkappaBalpha. Consistent with these data, mutant MEFs show increased sensitivity to TNFalpha-induced apoptosis. Our data provide in vivo evidence that NEMO/IKKgamma is the first essential, noncatalytic component of the IKK complex.

Animals↗
PubMed1999

Partial resistance to infection by R5X4 primary HIV type 1 isolates in an exposed-uninfected individual homozygous for CCR5 32-base pair deletion.

It is known that certain individuals remain persistently seronegative despite repeated exposure to HIV-1. Studies have shown that some exposed uninfected (EU) individuals who are homozygous for a 32-bp deletion in the CCR5 gene are resistant to infection with non-syncytium-inducing (R5) viruses. In the present investigation, we provide evidence that a highly exposed-uninfected individual with the CCR5 32-bp deletion (EUdelta32-1) also has partial resistance to syncytium-inducing (R5X4) HIV-1 viruses, when compared with unexposed-uninfected individuals with (UUdelta32-1 and UUdelta32-2) and without (UU-1 and UU-2) the 32-bp deletion. The partial resistance of EU cells was due neither to altered coreceptor expression, nor to specific mutation or deletion in the coding region of chemokine coreceptors CXCR4 and CCR3. While SDF-1, the ligand for CXCR4, blocked entry of R5X4 viruses to a similar extent in EUdelta32 and UUdelta32, there was a differential production of soluble factors by EUdelta32. Both CD4+ and CD8+ cells from EUdelta32-1 produced soluble factors that efficiently suppressed infection by HIV-1 R5X4 viruses when compared with supernatant from UUdelta32. These data provide evidence that additional soluble factors are involved in resistance to infection with R5X4 viruses.

CD4-Positive T-Lymphocytes↗
PubMed1999

Estimating the time of HTLV-I infection following mother-to-child transmission in a breast-feeding population in Jamaica.

Mother-to-child transmission of human T-cell lymphotropic virus type I (HTLV-I) is primarily due to prolonged breast-feeding (>6 months) in the postnatal period. Most infant infections are not identifiable until 12 to 18 months of age by available whole virus Western blot serologic tests because of their inability to distinguish passively transferred maternal antibody from infant antibody. We investigated two methods to assess more accurately the time of infant infection. In prospectively collected serial biospecimens, HTLV-I-specific immunoglobulin (Ig) isotypes of IgM and IgA were determined by Western blot and HTLV-I proviral DNA was detected by polymerase chain reaction (PCR). IgA and IgG reactivity was assessed in periodic serum samples from 16 HTLV-I-seropositive children while IgM reactivity was assessed in 9 of the 16 children. Approximately three to five samples were tested for each child. IgG reactivity was observed in 100% of children at 24 months of age and 73% of children at 6-12 months of age; however, this could represent maternal and not infant antibody. Both IgA and IgM reactivity were insensitive indicators of infection, with only 50% of children showing reactivity at 24 months of age. PCR testing was performed in biospecimens obtained from 11 of these children. An estimated median time of infection of 11.9 months was determined by PCR, which was similar to the median time to infection determined by whole virus Western blot (12.4 months; P = 0.72). PCR tests support a median time to infection that is similar to that estimated by whole virus Western blot.

Adult↗
PubMed1999

Prospective study on post-traumatic and postoperative sensory disturbances of the inferior alveolar nerve and infraorbital nerve in mandibular and midfacial fractures.

In a prospective study (January 1999 to December 1997), 34 patients with 26 mandibular and 20 midfacial fractures were investigated. All the fractures were managed by osteosynthesis. To evaluate the incidence and duration of recovery of post-traumatic and postoperative sensory disturbances, the following tests were carried out: sharp/blunt testing, and the two-point discrimination test as conventional clinical examination methods, and electromyographic recording of the masseter reflex to calibrate the clinical findings. To establish the sensory status of the inferior alveolar and the infraorbital nerves in the region of the fracture, and on the intact and control sides, the tests were performed pre-operatively and postoperatively on the seventh day, after 4 weeks and after 3, 6 and 12 months. The incidence of post-traumatic sensory disturbance was 46% for mandibular fractures and 65% for fractures to the midface (sharp/blunt test, two-point discrimination test). The rate of postoperative sensory disturbance in surgical treatment of mandibular fracture involving the region of the intra bony course of the inferior alveolar nerve, including the post-traumatic sensory disturbance, was 76.9%, and 55% following surgical treatment of midfacial fractures. The incidence of persistent sensory disturbances following surgical treatment was 7.7% in the case of mandibular fractures, and 15% in the case of midfacial fractures (sharp/blunt test, two-point discrimination test, masseter reflex). Recovery of neurological function is delayed in the presence of a displaced fracture (> 1 mm) as compared with non-displaced fractures. For the postoperative calibration of sensory disturbances, electromyographic recording of the masseter reflex from the fourth postoperative week onwards has proved useful.

Adolescent↗
PubMed1998

Impaired fetal T cell development and perinatal lethality in mice lacking the cAMP response element binding protein.

CREB, the cAMP response element binding protein, is a key transcriptional regulator of a large number of genes containing a CRE consensus sequence in their upstream regulatory regions. Mice with a hypomorphic allele of CREB that leads to a loss of the CREBalpha and delta isoforms and to an overexpression of the CREBbeta isoform are viable. Herein we report the generation of CREB null mice, which have all functional isoforms (CREBalpha, beta, and delta) inactivated. In contrast to the CREBalpha delta mice, CREB null mice are smaller than their littermates and die immediately after birth from respiratory distress. In brain, a strong reduction in the corpus callosum and the anterior commissures is observed. Furthermore, CREB null mice have an impaired fetal T cell development of the alpha beta lineage, which is not affected in CREBalpha delta mice on embryonic day 18.5. Overall thymic cellularity in CREB null mice is severely reduced affecting all developmental stages of the alpha beta T cell lineage. In contrast gamma delta T cell differentiation is normal in CREB mutant mice.

Animals↗
PubMed1997

Transmission X-ray microscopy of intact hydrated PtK2 cells during the cell cycle.

Transmission X-ray microscopy makes it possible to investigate biological specimens, i.e. cells and organelles, in their natural wet environment. The main processes determining the contrast in X-ray microscopy are photoelectric absorption and phase shift. X-ray microscopic experiments can therefore be carried out in both amplitude and phase contrast. The Göttingen X-ray microscope at the BESSY storage ring in Berlin is described. PtK2 cells were examined during different stages of the cell cycle. All major constituents of the mitotic apparatus, e.g. chromosomes, centromeres, microtubules and centrosomes, could be visualized, as well as the main structural compartments and organelles of the interphase cell, e.g. nuclear membrane, interphase chromatin, nucleolus and cytoplasmic mitochondria, as well as parts of the cytoskeletal apparatus. In this way new information can be obtained with regard to the ultrastructure of the constituents of intact and unstained cells at a resolution which bridges the gap between light microscopy and electron microscopy. The prospects for the future application of transmission X-ray microscopy in biomedical research are discussed.

Animals↗
PubMed1996

Male-to-female transmission of human T-cell lymphotropic virus types I and II: association with viral load. The Retrovirus Epidemiology Donor Study Group.

SUMMARY: Risk factors for male-to-female sexual transmission of human T-lymphotropic virus types I and II (HTLV-I/II) were investigated among HTLV-seropositive volunteer blood donors and their long-term (> or = 6 month) sex partners. Direction of transmission in concordantly seropositive pairs was assessed by analyzing risk factors for HTLV infection. Donors and their partners were also questioned regarding sexual behaviors during their relationships; HTLV antibody titers and viral load were determined for specimens from male partners. Among 31 couples in whom HTLV-infected men likely transmitted infection to their partners (11 HTLV-I and 20 HTLV-II) and 25 male-positive, female-negative couples (8 HTLV-I and 17 HTLV-II), HTLV transmitter men had been in their relationships longer (mean 225 months vs. 122 months) and had higher viral loads (geometric mean 257,549 vs. 2,945 copies/300,000 cells for HTLV-I; 5,541 vs. 118 copies/300,000 cells for HTLV-II) than non-transmitters (P = 0.018 and P = 0.001 for duration of relationship and viral load, respectively, logistic regression analysis). Transmitter men also tended to have higher antibody titers against various env and whole virus proteins than non-transmitters. The identification of high viral load and duration of relationship as risk factors provides a biologically plausible framework in which to assess risk of sexual transmission of the HTLVs.

Adult↗
PubMed1996

Multiparameter microscopic analysis of nucleolar structure and ribosomal gene transcription.

A survey of novel microscopic approaches for structural and functional analysis of subnucleolar compartments will be presented. Research on nucleolar structure and function concentrates predominantly on two distinct types of nucleoli: (1) nucleoli present during the interphase of the cell cycle in somatic tissue culture cells and (2) nucleoli present in meiotic cells, e.g. oocytes of amphibians. These nucleoli are found during meiotic prophase of oogenesis and are functional during several months of the diplotene stage of oogenesis. A further characteristic is the fact that these nucleoli are extrachromosomal, since they originate by selective ribosomal DNA (rDNA) amplification during the early pachytene stage of oogenesis. Miller-type chromatin spread preparations using transcriptionally active nucleoli, to a major part, contributed to our understanding of the structural organization of polymerase I directed pre-rRNA transcription. Although the structural organization of the template-associated pre-rRNA transcript is known in some detail from chromatin spreads, relatively little is known about structural aspects of pre-rRNA processing. In order to investigate this intriguing question in more detail, we have developed a computer-based densitometry analysis of both template-associated and template-dissociated pre-rRNA transcripts in order to follow the structural modification of pre-rRNA transcripts during processing. Another line of experiments is devoted to the in situ structure of actively transcribing genes in the nucleolus. In order to bridge the gap between light microscopy and electron microscopy we started video-enhanced light microscopical analysis of actively transcribing genes. Although the dimensions of individual spread genes are critical for detection by optical microscopy, we succeeded in obtaining the first series of images of transcribing genes in their "native' hydrated state. An additional promising type of microscopy is transmission X-ray microscopy. Recent progress in instrumentation as well as in sample preparation has allowed us to obtain the first images of density distribution within intact, fully hydrated nucleoli using amplitude-contrast and/or phase-contrast X-ray microscopy of non-contrasted, fully hydrated nucleoli at different states of transcriptional activity. Whereas the above mentioned investigations using video microscopy and X-ray microscopy are predominantly applicable to the analysis of amplified nucleoli in amphibian oocytes, which are characterized by an extremely high transcription rate of 80-90% of rDNA genes per individual nucleolus, structural analysis of the in situ arrangement of actively transcribing genes in somatic nucleoli as present in the interphase nucleus is far more difficult to perform, mainly due to the much lower number of simultaneously transcribed active genes per individual nucleolus. Visualization of actively transcribed gene clusters is approached by an integrated experimental assay using video microscopy, confocal laser scan microscopy, and antibodies against specific nucleolar proteins.

Animals↗
PubMed1996

[X-ray microscopy].

Owing to the short wavelengths of X-radiation X-ray microscopes allow higher resolution than optical microscopes. In contrast to electron microscopes, X-radiation can be used to study relatively thick aqueous specimens in their natural environment. X-ray microscopes require intense X-radiation, which is best provided by electron storage rings, as well as efficient X-ray optics. X-ray microscopes with zone plate optics are installed at the storage ring BESSY in Berlin for studies in the fields of biology, medicine, biophysics, colloid chemistry, and soil sciences.

Animals↗
PubMed1995

Mother-to-child transmission of human T-lymphotropic virus type II.

OBJECTIVE: To determine the frequency of mother-to-child transmission of human T-lymphotropic virus type II (HTLV-II) and to explore its association with breast-feeding. DESIGN: Prospective study of children born to a cohort of HTLV-II-infected pregnant women and a cross-sectional study of older siblings of these children. METHODS: Maternal sera were screened with an HTLV-I enzyme immunoassay that detects antibody to both HTLV-I and HTLV-II. Confirmatory serologic testing and viral typing were performed by Western blot, radioimmunoprecipitation assay, enzyme immunoassay with HTLV type-specific proteins, and polymerase chain reaction (PCR) analysis of DNA from peripheral blood mononuclear cells. The presence of HTLV was evaluated in children by serial serologic and PCR testing. Molecular analysis of PCR products from infected mother-child pairs was performed by means of restriction fragment length polymorphism of HTLV-II long-terminal repeated sequences. RESULTS: Twenty-nine HTLV-II-infected women were identified, and these 29 women had 30 pregnancies during the study. Of 28 live infants born to infected women, 19 were examined and none was infected with HTLV-II. Sixteen older children less than 10 years of age who were born previously to the infected women were also examined; two were infected with HTLV-II. One infected child was breast fed for 2 months and the second was not breast fed. The viral patterns of restriction fragment length polymorphism in the two infected children were distinct, but the viral pattern in each child was identical to that of her mother's virus, suggesting mother-to-child transmission. Overall, among examined children, 1 of 7 breast-fed children (14%; 95% confidence interval: 0, 40) and 1 of 28 children who were not breast fed (3.6%; 95% confidence interval: 0, 10) were infected with HTLV-II. CONCLUSION: Mother-to-child transmission of HTLV-II occurs both with and without breast-feeding and at rates similar to those of HTLV-I. We believe that this is the first demonstration of mother-to-child transmission of HTLV-II in the absence of breast-feeding.

Blotting, Western↗