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G May

Publications and source records attributed to G May.

At least 55 records · Page 3Linked to original sources
PubMed1994

A mating-type factors of Coprinus cinereus have variable numbers of specificity genes encoding two classes of homeodomain proteins.

We have identified the seven genes that constitute the A43 mating-type factor of Coprinus cinereus and compare the organisation of A43 with the previously characterised A42 factor. In both, the genes that trigger clamp cell development, the so-called specificity genes, are separated into alpha and beta loci by 7 kb of noncoding sequence and are flanked by homologous genes alpha-fg and beta-fg. The specificity genes are known to encode two classes of dissimilar homeodomain (HD1 and HD2) proteins and have different allelic forms which show little or no cross-hybridisation. By partial sequencing we identified a divergently transcribed HD1 (a1-2) and HD2 (a2-2) gene in the A43 alpha locus. a2-2 failed to elicit clamp cell development in three different hosts, suggesting that it is non-functional. a1-2 elicited clamp cells in an A42 host that has only an HD2 gene (a2-1) in its alpha locus, thus demonstrating that the compatible A alpha mating interaction is between an HD1 and an HD2 protein. The A43 beta locus contains three specificity genes, the divergently transcribed HD1 and HD2 genes b1-2 and b2-2 and a third HD1 gene (d1-1) that was shown by hybridisation and transformation analyses to be functionally equivalent to d1-1 in A42. An untranscribed footprint of a third A42 HD1 gene, c1-1, was detected between the A43 b2-2 and d1-1 genes by Southern hybridisation.

Amino Acid Sequence↗
PubMed1994

Comparison of two b1 alleles from within the A mating-type of the basidiomycete Coprinus cinereus.

We cloned and sequenced the b1 specificity gene, b1-2, from the A43 mating-type locus of the basidiomycete Coprinus cinereus, to compare its molecular structure to a previously published allele. The b1-2 gene was identified and isolated using a transformation assay for A-activity. The nucleotide (nt) sequence was determined and compared to the published sequence for the b1 specificity gene of the A42 mating-type locus. Both genes map to the same physical location within the A mating-type locus and conserved structural organization is observed at both the genomic and the protein level. Sequence alignments show that the two alleles share 73% overall nt sequence identity for the open reading frames (ORFs) and 68% overall amino acid (aa) sequence identity for the deduced polypeptides. Allowing for conservative substitutions, the overall aa sequence similarity is 79%. Comparison of the deduced aa sequences reveals several conserved structural motifs, including a DNA-binding homeodomain, putative bipartite nuclear localization signal sequences, and four predicted dimerization motifs. Regions rich in Pro and hydroxylated aa (Ser and Thr) are also common to both alleles. Sequence similarity varies greatly along the length of the gene at both the nt and aa levels. In general, similarity increases progressively from the N- to the C-terminal end with variable patterns of similarity observed for individual exons and the predicted motifs they encode. The low sequence similarity observed in the N terminus suggests that variability in this region may be involved in non-self recognition. Differing levels of positional and compositional constraint are apparent for different functional domains.

Alleles↗
PubMed1994

Failure of in vitro T-cell assays to predict clinical outcome after human kidney transplantation.

Allotransplant rejection is a T-cell-dependent reaction. Functional in vitro T-cell assays are being used widely for donor-recipient matching in bone marrow transplantation and have recently been used in some centres for transplant monitoring. In order to assess tolerance induction after clinical transplantation, we measured the T-cell response of the host against donor spleen cells of 33 kidney transplant patients before and every 3 months after transplantation over a period of 18 months. The T-cell reactivity before transplantation was not significantly different in any of the assays in rejecting and non-rejecting patients. In the classical mixed lymphocyte culture (MLC), a donor-specific loss of reactivity was seen only in a patient with a CMV-associated irreversible transplant rejection. One patient with chronic rejection acquired a very high MLC response against donor spleen cells and a high response against third-party cells. Little or nonspecific changes were seen in the MLCs of all other patients. Using the method of limiting dilution analysis (LDA), we found a significant reduction of donor-specific cytotoxic T-cell precursors (CTL-p) within the first 3 months after transplantation in most patients with high antidonor CTL-p frequencies before transplantation. The reduction of donor-specific CTL-p was seen in patients with rejection episodes as well as in patients without. Thus we conclude, in contrast to others, that MLC and CTL-p LDA have no predictive value on the outcome of clinical transplantation.

Clonal Deletion↗
PubMed1994

Urinary Tamm-Horsfall protein as a marker of renal transplant function.

In a total of 428 urine samples collected from 15 patients aged between 23 and 60 years after cadaveric kidney transplantation during a postoperative hospital stay, Tamm-Horsfall protein (THP) was quantitatively determined using the ELIAS SYNELISA-THP immunoassay. All patients were treated with azathioprine, cyclosporine, prednisolone, given an intraoperative high-dose single antilymphocyte globulin bolus and discharged with functioning grafts. In clinically uncomplicated courses, even after immediate transplant function, the recovery of graft function took on average 7 days. Thereafter the urinary THP excretion was relatively stable and amounted, on average, to 14.5 +/- 4.9 mg/24 h (i.e. was at the lower limit of normal urinary THP excretion). In cases of delayed onset of graft function of undetermined origin accompanied by extremely reduced urinary THP excretion, the functional recovery, whether spontaneous or brought about by treatment, was characterized by a continuous increase in urinary THP excretion. In connection with interstitial rejections urinary THP excretion seems not to be a recommendable diagnostic parameter. Daily measurement of urinary THP is, however, suitable for monitoring the functional state of transplanted kidneys.

Adult↗
PubMed1994

Effects of PUVA therapy on kidney allografts: results of a randomized prospective double-blind study.

After successful experimental organ transplant studies on the efficacy of PUVA therapy combining donor pretreatment with the photosensitizer 8-methoxypsoralen (P) and the ex vivo irradiation of organs with long-wave ultraviolet light (UVA) prior to transplantation, we started in 1989 the first randomized, prospective, double-blind study to clarify the efficacy of PUVA therapy in human kidney transplantation. This study included 50 kidney donors, 25 of whom were PUVA-treated. A total of 75 kidneys were transplanted in Berlin, Halle and Rostock. The complete data of these 75 recipients were available for the final evaluation. The PUVA group (n = 36) and the non-PUVA group (n = 39) were not statistically significantly different as to donor and recipient data. Regarding the results, no differences were seen in initial hospitalization time, early graft function, rejection rate, number and time of rejection episodes. After a follow-up of 24 months, both graft survival (PUVA vs. non-PUVA: 75% vs. 71.8%) and patient survival (97.2% vs. 97.4%, respectively) were comparably high. PUVA therapy did not influence the development of vascular rejection. Interestingly, the rate of late graft loss after the 6th posttransplant month was lower, but not statistically significantly so, in the PUVA than in the non-PUVA-group (2 vs. 6 graft losses). Thus, PUVA-pretreated kidneys may be associated with a reduced development of chronic rejection.

Adolescent↗
PubMed1994

Pretransplant serum IgA concentration and IgA-anti-Fab autoantibody activity as prognostic indicators of kidney graft survival.

IgA concentration and IgA-anti-Fab autoantibody activity were tested in pretransplant sera of 308 kidney graft recipients. Recipients with a serum IgA concentration of 2 g/l or greater had a 1-year graft survival rate of 83%, compared with a 68% rate in recipients with serum IgA of less than 2 g/l (P < 0.005). Serum IgA concentration and IgA-anti-Fab autoantibody activity were significantly associated (r = 0.38, P < 0.0001). Recipients with a high pretransplant IgA-anti-Fab activity had a significantly better graft survival rate (81%) than patients with low pretransplant IgA-anti-Fab (67%, P < 0.025). When IgA-anti-Fab and serum IgA were considered together, 137 recipients with high IgA-anti-Fab and high serum IgA had a 86% 1-year graft survival rate, which was significantly better than the 63% survival rate in patients with low IgA-anti-Fab and low serum IgA (P < 0.0005). The pretransplant serum IgA level and IgA-anti-Fab autoantibody activity were excellent predictors of kidney graft outcome.

Autoantibodies↗
PubMed1994

[Immunosuppression and treatment of graft rejection after kidney transplantation].

Following the development of new immunosuppressive drugs and improved recognition of immunological events, clinical kidney transplantation has become a routine procedure. At present, 1-year graft survival rates of over 90% are not exceptional. Whilst the baseline immunosuppression is relatively uniformly managed. long-term treatment is subject to different protocols and strategies. In the diagnosis and treatment of acute rejection crises the options are limited. For chronic rejections both concepts for diagnosis and treatment schedules are inadequate. Because there is no one immunosuppressive drug or drug combination that can be used to solve all these problems, it is essential that new drugs or strategies be developed that allow elaboration of individual therapy and, above all, further improvement of the long-term results of kidney transplantation.

Animals↗
PubMed1993

Two related recombinases are required for site-specific recombination at dif and cer in E. coli K12.

The stable inheritance of ColE1-related plasmids and the normal partition of the E. coli chromosome require the function of the Xer site-specific recombination system. We show that in addition to the XerC recombinase, whose function has already been implicated in this system, a second chromosomally encoded recombinase, XerD, is required. The XerC and XerD proteins show 37% identity and bind to separate halves of the recombination site. Both proteins act catalytically in the recombination reaction. Recombination site asymmetry and the requirement of two recombinases ensure that only correctly aligned sites are recombined. We predict that normal partition of most circular chromosomes requires the participation of site-specific recombination to convert any multimers (arising by homologous recombination) to monomers.

Amino Acid Sequence↗
PubMed1992

Effect of ATG prophylaxis in sensitized and non-sensitized kidney graft recipients.

In our effort to find an optimum immunosuppressive protocol for kidney transplantation we introduced two forms of ATG prophylaxis: 1. high-dose single-bolus prophylaxis (9 mg/kg) in non-sensitized patients (PRA < 5%); and 2. low-dose 8-day prophylaxis (1.5-3.0 mg/kg) in sensitized patients (PRA > 5%). A total of 204 kidney graft recipients were included in this study and treated with a triple-drug therapy (TDT). In comparison with TDT-treated controls, in sensitized patients the 8-day ATG prophylaxis resulted in a reduced rate of rejection episodes (25.5% vs 47%), an improved 1-year graft survival (82% vs 71%) and patient survival (94% vs 90%). In non-sensitized patients the high-dose single-bolus ATG prophylaxis induced a T-cell lymphopenia lasting 4 to 5 days and, in comparison with the corresponding controls, resulted in a shortened hospital stay (31.2 days vs 36.7 days), a reduced rate of rejection episodes (25.5% vs 53%), an improved 1-year graft survival (92% vs 86%) and patient survival (100% vs 94%).

Antilymphocyte Serum↗
PubMed1992

Activity of oxidative routes of metabolism of debrisoquin, mephenytoin, and dapsone is unrelated to the pathogenesis of vinyl chloride-induced disease.

The hypothesis, that cytochrome P4502D6, cytochrome P4502CMP, cytochrome P4503A4 or N-acetyl-transferase may form active intermediary metabolites that could be etiologically related to vinyl chloride-induced disease was investigated in 21 drug-free workers with previous development of vinyl chloride-induced disease and in 23 drug-free workers from the same plant who did not develop the syndrome. Each subject received simultaneous oral administration of debrisoquin (10 mg), mephenytoin (100 mg), and dapsone (100 mg). Measurement of the debrisoquin recovery ratio, the 8-hour recovery of 4-hydroxymephenytoin, and the dapsone recovery ratio in the subsequent 8-hour urine sample provided in vivo phenotypic indexes of cytochromes P4502D6, P4502CMP, and P4503A4 activity, respectively. An 8-hour blood sample was used to measure the acetylation ratio, a measure of N-acetyltransferase activity. The frequency distributions of each drug metabolizing activity were similar between groups. Within this small sample, there was no evidence to implicate cytochromes P4502D6, P4502CMP, and P4503A4 and N-acetyltransferase in the pathogenesis of vinyl chloride-induced disease.

Arylamine N-Acetyltransferase↗
PubMed1992

The association of kidney graft outcome with pretransplant serum IgG-anti-F(ab')2 gamma activity.

Pretransplant sera of 474 kidney graft recipients were tested for IgG-anti-F(ab')2 gamma activity. The patients had significantly higher IgG-anti-F(ab')2 gamma activity than healthy controls (P = 0.0004). Serum lymphocytotoxic antibodies were correlated with IgG-anti-F(ab')2 gamma (P = 0.004), whereas CMV infection and blood transfusions were not. We found a significant association between pretransplant IgG-anti-F(ab')2 gamma activity and early and 1-year kidney graft outcome. This association was pronounced in recipients with no lymphocytotoxic antibodies. Recipients with immediately functioning grafts and a creatinine < 130 mumol/L at 1 year had strikingly higher pretransplant IgG-anti-F(ab')2 gamma activity than patients with graft failure (P < 0.0001).

Antibodies, Anti-Idiotypic↗
PubMed1991

Purification and characterization of Ku-2, an octamer-binding protein related to the autoantigen Ku.

The octamer motif (ATTTGCAT) is an important regulatory element in eukaryotic gene expression. A previously unidentified protein that recognizes this motif has been isolated from the human B cell line, Daudi. The protein, which we term Ku-2, bears a close resemblance to the DNA-binding autoantigen Ku. Like Ku, it is a heterodimer with subunits of 83 and 72 kDa; antisera raised against either subunit of Ku cross-react with Ku-2. Two peptides have been sequenced and show a strong similarity to regions in the corresponding subunits of Ku. The sequences are not identical, however, suggesting that Ku-2 may be a B cell homologue of Ku. Both Ku and Ku-2 bind to the termini of DNA duplexes, but Ku-2 also binds to an internal octamer motif. It is not known whether Ku shares the latter property or whether the octamer binding is a consequence of sequence differences between the two proteins. Ku-2 does not react with antisera against the POU domain of the octamer-binding protein Oct-2, indicating that the DNA binding domains of the two proteins are dissimilar despite the ability of both to bind to the octamer motif. We discuss the evidence for the existence of a family of octamer-binding proteins related to Ku.

Amino Acid Sequence↗
PubMed1991

Molecular analysis of the Coprinus cinereus mating type A factor demonstrates an unexpectedly complex structure.

We report here the molecular cloning of the A43 mating type factor from Coprinus cinereus, a basidiomycetous fungus. Our molecular analyses revealed an unexpected source of variation in the A factor. Though genetic studies have demonstrated that A has two subunits, alpha and beta, we located three nonoverlapping fragments in the A43 region that have A factor function following DNA-mediated transformation. The three fragments demonstrate no similarity to one another as judged by restriction enzyme maps and by hybridization on Southern blots. We conclude that the A43 factor is composed of at least three subunits. When strains carrying different A factors are examined by hybridization to the cloned subunits, extensive polymorphism is seen. Both intensity of hybridization and restriction fragment lengths vary between strains. Some strains fail to show any hybridization to a probe. In contrast, other strains from widely separated geographic locations apparently share very similar subunits. From comparative restriction enzyme mapping of A43 and a mutated A43 factor, we inferred that a 12-kb deletion in the A factor was responsible for the constitutive, dominant phenotype of the mutated A factor. The results of transformation experiments support an activator model for the activity of the A factor in regulating the A pathway.

Biological Evolution↗
PubMed1991

[Risk of CMV infection and illness after kidney transplantation].

Between 1980 and 1986 465 cadaveric kidney transplants were performed at the Kidney Transplant Centre Berlin-Friedrichshain. The post-transplant risk to acquire a cytomegalovirus (CMV) infection depended on the preoperative CMV antibody status of donor and recipient, on the nettoimmunosuppression and on the recipient's age. The highest infection rate and the most serious courses showed seronegative recipients from seropositive donors. The typical time interval of clinical manifestation included the postoperative months 1-3. A significant dependence of the frequency of infection on different immunosuppressive protocols could not be proven. But there was a significant coincidence between CMV infection and rejection crises. In spite of the raised frequency of rejection crises an influence of the CMV infection on the 1-year-graft and patient survival rates could not be demonstrated. Both an early diagnosis and an adequate therapy are of particular importance.

Age Factors↗