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N Domke

Publications and source records attributed to N Domke.

At least 19 recordsLinked to original sources
PubMed2006

[Intraocular pressure and corneal thickness. A comparison between non-contact tonometry and applanation tonometry].

OBJECTIVE: Corneal thickness and deformation seem to have a considerable influence on intraocular pressure measurement. Due to differences in the corneal deformation in either non-contact tonometry or applanation tonometry, both methods should be compared in the same patient group depending on central corneal thickness. METHODS: In 106 eyes of 55 patients (18 males, 37 females, age 17-89 years, mean 63.3 years) with glaucoma and central corneal thickness between 409 and 644 microm (Orbscan II pachymetry) intraocular pressure was measured in each eye with non-contact tonometry (Reichert AT550) and 30 min later with Goldman applanation tonometry. RESULT: Non-contact tonometry as well as applanation tonometry showed a positive correlation between measured intraocular pressure and corneal thickness. The steepness of the line of regression was 0.33 mmHg per 10 microm of corneal thickness in non-contact tonometry and 0.17 mmHg per 10 microm of corneal thickness in applanation tonometry. CONCLUSION: Independently of the large differences in individual pressure measurements between non-contact tonometry and applanation tonometry, we found higher IOP values with non-contact tonometry in thicker corneas as compared with applanation tonometry. In thinner corneas there was a better correspondence between both methods. Thus, it seems very likely that corneal rigidity increases with corneal thickness.

Adolescent↗
PubMed2001

Elevated temperature differentially affects virulence, VirB protein accumulation, and T-pilus formation in different Agrobacterium tumefaciens and Agrobacterium vitis strains.

That gene transfer to plant cells is a temperature-sensitive process has been known for more than 50 years. Previous work indicated that this sensitivity results from the inability to assemble a functional T pilus required for T-DNA and protein transfer to recipient cells. The studies reported here extend these observations and more clearly define the molecular basis of this assembly and transfer defect. T-pilus assembly and virulence protein accumulation were monitored in Agrobacterium tumefaciens strain C58 at different temperatures ranging from 20 degrees C to growth-inhibitory 37 degrees C. Incubation at 28 degrees C but not at 26 degrees C strongly inhibited extracellular assembly of the major T-pilus component VirB2 as well as of pilus-associated protein VirB5, and the highest amounts of T pili were detected at 20 degrees C. Analysis of temperature effects on the cell-bound virulence machinery revealed three classes of virulence proteins. Whereas class I proteins (VirB2, VirB7, VirB9, and VirB10) were readily detected at 28 degrees C, class II proteins (VirB1, VirB4, VirB5, VirB6, VirB8, VirB11, VirD2, and VirE2) were only detected after cell growth below 26 degrees C. Significant levels of class III proteins (VirB3 and VirD4) were only detected at 20 degrees C and not at higher temperatures. Shift of virulence-induced agrobacteria from 20 to 28 or 37 degrees C had no immediate effect on cell-bound T pili or on stability of most virulence proteins. However, the temperature shift caused a rapid decrease in the amount of cell-bound VirB3 and VirD4, and VirB4 and VirB11 levels decreased next. To assess whether destabilization of virulence proteins constitutes a general phenomenon, levels of virulence proteins and of extracellular T pili were monitored in different A. tumefaciens and Agrobacterium vitis strains grown at 20 and 28 degrees C. Levels of many virulence proteins were strongly reduced at 28 degrees C compared to 20 degrees C, and T-pilus assembly did not occur in all strains except "temperature-resistant" Ach5 and Chry5. Virulence protein levels correlated well with bacterial virulence at elevated temperature, suggesting that degradation of a limited set of virulence proteins accounts for the temperature sensitivity of gene transfer to plants.

Agrobacterium tumefaciens↗
PubMed2000

VirB6 is required for stabilization of VirB5 and VirB3 and formation of VirB7 homodimers in Agrobacterium tumefaciens.

VirB6 from Agrobacterium tumefaciens is an essential component of the type IV secretion machinery for T pilus formation and genetic transformation of plants. Due to its predicted topology as a polytopic inner membrane protein, it was proposed to form the transport pore for cell-to-cell transfer of genetic material and proteinaceous virulence factors. Here, we show that the absence of VirB6 leads to reduced cellular levels of VirB5 and VirB3, which were proposed to assist T pilus formation as minor component(s) or assembly factor(s), respectively. Overexpression of virB6 in trans restored levels of cell-bound and T pilus-associated VirB5 to wild type but did not restore VirB3 levels. Thus, VirB6 has a stabilizing effect on VirB5 accumulation, thereby regulating T pilus assembly. In the absence of VirB6, cell-bound VirB7 monomers and VirB7-VirB9 heterodimers were reduced and VirB7 homodimer formation was abolished. This effect could not be restored by expression of VirB6 in trans. Expression of TraD, a component of the transfer machinery of the IncN plasmid pKM101, with significant sequence similarity to VirB6, restored neither protein levels nor bacterial virulence but partly permitted T pilus formation in a virB6 deletion strain. VirB6 may therefore regulate T pilus formation by direct interaction with VirB5, and wild-type levels of VirB3 and VirB7 homodimers are not required.

Agrobacterium tumefaciens↗
PubMed1999

TraC of IncN plasmid pKM101 associates with membranes and extracellular high-molecular-weight structures in Escherichia coli.

Conjugative transfer of IncN plasmid pKM101 is mediated by the TraI-TraII region-encoded transfer machinery components. Similar to the case for the related Agrobacterium tumefaciens T-complex transfer apparatus, this machinery is needed for assembly of pili to initiate cell-to-cell contact preceding DNA transfer. Biochemical and cell biological experiments presented here show extracellular localization of TraC, as suggested by extracellular complementation of TraC-deficient bacteria by helper cells expressing a functional plasmid transfer machinery (S. C. Winans, and G. C. Walker, J. Bacteriol. 161:402-410, 1985). Overexpression of TraC and its export in large amounts into the periplasm of Escherichia coli allowed purification by periplasmic extraction, ammonium sulfate precipitation, and column chromatography. Whereas TraC was soluble in overexpressing strains, it partly associated with the membranes in pKM101-carrying cells, possibly due to protein-protein interactions with other components of the TraI-TraII region-encoded transfer machinery. Membrane association of TraC was reduced in strains carrying pKM101 derivatives with transposon insertions in genes coding for other essential components of the transfer machinery, traM, traB, traD, and traE but not eex, coding for an entry exclusion protein not required for DNA transfer. Cross-linking identified protein-protein interactions of TraC in E. coli carrying pKM101 but not derivatives with transposon insertions in essential tra genes. Interactions with membrane-bound Tra proteins may incorporate TraC into a surface structure, suggested by its removal from the cell by shearing as part of a high-molecular-weight complex. Heterologous expression of TraC in A. tumefaciens partly compensated for the pilus assembly defect in strains deficient for its homolog VirB5, which further supported its role in assembly of conjugative pili. In addition to its association with high-molecular-weight structures, TraC was secreted into the extracellular milieu. Conjugation experiments showed that secreted TraC does not compensate transfer deficiency of TraC-deficient cells, suggesting that extracellular complementation may rely on cell-to-cell transfer of TraC only as part of a bona fide transfer apparatus.

Agrobacterium tumefaciens↗
PubMed1999

Vir proteins stabilize VirB5 and mediate its association with the T pilus of Agrobacterium tumefaciens.

Three VirB proteins (VirB1*, VirB2, and VirB5) have been implicated as putative components of the T pilus from Agrobacterium tumefaciens, which likely mediates binding to plant cells followed by transfer of genetic material. Recently, VirB2 was indeed shown to be its major component (E.-M. Lai and C. I. Kado, J. Bacteriol. 180:2711-2717, 1998). Here, the influence of other Vir proteins on the stability and cellular localization of VirB1*, VirB2, and VirB5 was analyzed. Solubility of VirB1* and membrane association of VirB2 proved to be inherent features of these proteins, independent of virulence gene induction. In contrast, cellular levels of VirB5 were strongly reduced in the absence of other Vir proteins, indicating its stabilization by protein-protein interactions. The assembly and composition of the T pilus were analyzed in nopaline strain C58(pTiC58), its flagellum-free derivative NT1REB(pJK270), and octopine strain A348(pTiA6) following optimized virulence gene induction on solid agar medium. In all strains VirB2 was the major pilus component and VirB5 cofractionated during several purification steps, such as ultracentrifugation, gel filtration, and sucrose gradient centrifugation. VirB5 may therefore be directly involved in pilus assembly, possibly as minor component. In contrast, secreted VirB1* showed no association with the T pilus. In-frame deletions in genes virB1, virB2, virB5, and virB6 blocked the formation of virulence gene-dependent extracellular high-molecular-weight structures. Thus, an intact VirB machinery as well as VirB2 and VirB5 are required for T-pilus formation.

Agrobacterium tumefaciens↗
PubMed1994

Immunogenetic and serological investigations in nonpregnant and in pregnant women with a history of recurrent spontaneous abortions. German RSA/IVIG Study Group.

In the context of a controlled multicenter study on intravenous immunoglobulin (IVIG) treatment of patients with a history of unexplained recurrent spontaneous abortions (RSA), a number of controversial immunological parameters were evaluated prior to and during pregnancy with respect to their diagnostic and/or prognostic significance. A total of 390 serum samples from 52 patients were investigated. Sharing of 2 or more HLA (A, B, DR, DQ) antigens was significantly more frequent in RSA couples than in controls. The rate of cytotoxic or Fc-receptor (FcR)-blocking antibodies was not significantly lower in RSA patients than in individuals with normal pregnancies. Both tumor necrosis factor-alpha (TNF-alpha) levels and IgG anticardiolipin antibodies (IgG-ACA) were significantly increased in the patient group. While the occurrence of HLA sharing, cytotoxic/FcR-blocking antibodies and IgG-ACA did not correlate with the outcome of pregnancy, TNF-alpha levels were found to be significantly higher in patients with subsequent miscarriage than in those with successful pregnancy. IgG-ACA, if present, significantly decreased during the course of successful pregnancy but remained high in patients with subsequent abortion. It is concluded that the diagnostic and/or prognostic value of HLA sharing and cytotoxic/FcR-blocking antibodies has been overestimated while TNF-alpha and ACA levels are potential diagnostic markers and/or exhibit prognostic significance in subgroups of RSA patients.

Abortion, Habitual↗
PubMed1992

[Anti-phospholipid antibodies in gynecology and obstetrics].

Anti-phospholipid-antibodies are connected with many diseases. In gynecology and obstetrics they are related to habitual abortion, preeclampsia, intrauterine retardiation and thrombembolic events. Pathogenetic conceptions, the diagnosis, problems in contraceptions, pregnancies and puerperium are explained. Their search and an individual trial of therapy should be done in spite of unknown mechanism of effectiveness.

Antiphospholipid Syndrome↗
PubMed1991

[Prospective immunohistologic search for metastases using monoclonal anti-cytokeratin antibodies in gynecologic malignancies].

A higher prevalence of positive lymph node metastases can be found with immunohistological methods in comparison with conventional technique. We examined the lymph nodes from 20 patients with gynecological malignant tumors. We found in 304 lymph nodes with conventional technique 3.3% metastases. With immunohistological methods we showed in 9.9% of the lymph nodes metastases.

Antibodies, Monoclonal↗
PubMed1991

[Cytogenetic study of peripheral lymphocyte culture in couples with habitual abortion].

We report on a cytogenetic investigation of lymphocytes in 241 couples and six women with at least three abortions. We found a balanced reciprocal translocation three times (1.2% of couples) and a balanced Robertsonian translocation twice (0.8% of couples). Four numerical aberrations of the gonosomes were detected (three of them as a mosaic), and one deletion Xq- as a mosaic. The heterochromatic region of the chromosomes 1, 9 or 16 was enlarged in 12 couples (4.9%). There was no couple with a pericentric inversion of the chromosomes 1 or 9. The enlarged Y-chromosome (five males) according to our results does not play any important role for the reproduction. Five translocations and one supernumerary chromosome each in one cell only indicate an enlarged frequency of breakage events in couples with habitual abortion.

Abortion, Habitual↗
PubMed1989

[Retrospective immunohistologic search for metastases using monoclonal anti-cytokeratin antibodies in lymph nodes of patients with stage Ib-IIb cervix cancer dying within 5 years].

With immunohistological methods using monoclonal antibodies more metastases were detected in carcinomas today. We examined 10 women, where the carcinoma of the cervix was removed today in healthy and where the lymph nodes were free of metastases. With use of the monoclonal cytokeratin-antibody lu-5 it was not possible to improve the diagnostic. In a histomorphological differentiation of grade 2 or 3 a radiation should be considered.

Adult↗
PubMed1988

[Immunologic aspects of habitual abortion and intrauterine fetal death].

Habitual abortions and intrauterine death represent diagnostic and therapeutic problems in spite of application of near all diagnostic possibilities. The appearance of autoantibodies to nuclear and extractable nuclear antigens as well as occurrence of phospholipid-antibodies may be associated with negative course of pregnancy. Furthermore problems of autoantibodies to DNA, the role of HLA-system trophoblast antigens and other reasons will be explained. Treatment facilities are referred, too.

Abortion, Habitual↗
PubMed1988

[Diagnostic difficulties in immunologically-induced infertility].

This is a report on diagnostics in a patient who anamnestically had three abortions in her history. To look for in search of the cause we found a little submucosal uterine myoma which could not to be removed by curettement. Thus, a gynaecological laparotomy had to be carried out. Paraclinical examinations finally proved the lupus-anticoagulant-factor.

Abortion, Habitual↗
PubMed1987

[Correlation of sonomorphologic placental maturity with the L/S ratio and creatinine level in the amniotic fluid].

With 184 L/S-ratio determinations and 132 creatinine determinations in amniotic fluid we tried to show a connection between these parameters and sonographically provable changes of placental structures. We found no relationship between placental grading and fetal lung and renal maturity by statistical processing of the results, considering gestational age. There is between L/S-ratio and creatinine determinations no statistical relationship, too.

Amniotic Fluid↗
PubMed1986

[Sonographically detectable changes in placental structures in pregnancy. 4. Statistical comparison of the frequency distribution of placental stages 0-3 in newborn infants in a pregnancy of 37-42 weeks duration].

Among women with a duration of pregnancy between 37 and 42 gestational weeks procentual frequency, confidence intervals of O. Bunke, pounts of separability and areas of unsharpners were analysed. 1412 sonographical examinations were done in 645 pregnant women. Stage 0 was found statistically significant more frequent with error of probability alpha = 0.05 until the 30. week of pregnancy, stage 1 between the 21. and 36. week of pregnancy, stage 2 between the 33. and 36. gestational week and stage 3 in 37. and 38. week. Transformation (areas of unsharpness) from stage 0 to stage 1 occurs between the 24. and 32. gestational week, from stage 1 to stage 2 between the 31. and 34. week, from stage 2 to stage 3 between the 36. and 42. gestational week.

Birth Weight↗
PubMed1986

[Sonographically detectable changes in placental structures in pregnancy. 5. Statistical comparison of the frequency distribution of placental stages 0-3 in newborn infants in a pregnancy of less than 37 weeks duration].

The analysis of sonographically provable changes of placental structures in 97 pregnant women (202 examination) shows in cases with a duration of pregnancy less than 37 gestational weeks that stage 0 could be found statistically significant more frequent until the 32nd week of pregnancy, stage 1 in the whole pregnancy, stage 2 and 3 between the 29. and 36. gestational week. Stage 0 and 1 don't effect prematurity; however stages 2 and 3 could be proved before the 32nd or 34th week of pregnancy in 41 or 100% of examination respectively and effect a premature birth. Stage 2 could be proved 2,8 times more frequent and stage 3 4 times more frequent in premature babies than in newborns with a normal duration of pregnancy.

Birth Weight↗
PubMed1986

[Sonographically detectable changes in placental structures in pregnancy. 6. Effect of sonographic placental morphology on premature labor and intrauterine growth retardation].

Influence of sonographically demonstrable changes of placental structure on prematurity and intrauterine retardation was analysed and concerning its statistical rehability in 807 gravids. While the stages 0 and 1 don't effect prematurity and intrauterine retardation, the stage 2 is accompanied premature infant of normal birthweight if proved before the 32nd week of pregnancy. If stage 3 appears before the 34. week of pregnancy we found in 30.6% a small for date newborn, in 64% a normal weight and in 80% a small for date premature newborn. In comparison with the normal weight newborn the difference is statistically significant with an error probability of alpha = 0.05.

Birth Weight↗
PubMed1986

[Immunologic aspects of pregnancy].

Immunological studies of normal pregnancies as well as of recurrent spontaneous abortions serve as indicators that certain immune responses are linked to reproductive success or failure. Some of the observed often contradictory phenomena concerning intraspecies mammalian pregnancies will be discussed in this review.

Abortion, Habitual↗