Bicentric origin of sickle hemoglobin among the inhabitants of Mauritius Island.
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Africa↗
Biomedical subjects
R Nagel
Publications and source records attributed to R Nagel.
Influence of 3,4-dichloroaniline (3,4-DCA) on benthic invertebrates in indoor experimental streams.
The influence of 3,4-dichloroaniline (3,4-DCA) on benthic invertebrates has been examined. Acute toxicity tests were carried out with the following species: Pristina longiseta, Aelosoma variegatum (Oligochaeta), Hydrozetes lacustris (Acarina), Planorbarius corneus, and Gyraulus albus (Planorbidae). LC50 values (96 hr) were obtained for Pri. longiseta (2.5 mg/liter) and for Hy. lacustris (4.7 mg/liter). For all other species ranges of toxicity (maximal concentration with 0% dead to minimum concentration with 100% dead) were determined. These ranges were 0.8-20 mg/liter 3,4-DCA for Pri. longiseta, 1.6-20 mg/liter, 3,4-DCA for Hy. lacustris, 10-20 mg/liter 3,4-DCA for G. albus, 50-100 mg/liter 3,4-DCA for Pl. corneus, and 10 mg/liter 3,4-DCA (maximal concentration with 0% dead; minimum concentration with 100% dead was not determined) for Ae. variegatum. In two experimental streams, the recolonization of benthic organisms into defined sample areas was studied. Therefore, a phase without chemical treatment was compared with a following exposure phase. Test concentrations were 0.2 and 1.4 mg/liter 3,4-DCA (nominal concentrations). Significant effects were the complete extinction of Pri. longiseta in 0.2 mg/liter 3,4-DCA within the first 3 weeks of exposure, as well as the reduction of immigrating individuals of another species of Pristina in both test concentrations, and of Hy. lacustris and Stentor sp. in 1.4 mg/liter 3,4-DCA.(ABSTRACT TRUNCATED AT 250 WORDS)
Aniline Compounds↗
Toxicity of complex chemical mixtures: acute and long-term effects on different life stages of zebrafish (Brachydanio rerio).
Acute and long-term toxicity of 3,4-dichloroaniline and lindane to zebrafish were examined in tap water and water from the Rhine River and the toxicity of the binary mixture 3,4-dichloroaniline/lindane in tap water was investigated. The acute toxicity of 3,4-dichloroaniline and lindane was not influenced by the complex matrix of river water compared with tap water. The binary mixture of 3,4-dichloroaniline and lindane demonstrated an additive effect in the acute test. The survival rate of early life stages in river water was reduced by lindane (80 micrograms/liter), whereas the effects of 3,4-dichloroaniline on survival and growth were visible but not significant. The binary mixture of 2 micrograms/liter, 3,4-dichloroaniline and 40 micrograms/liter lindane in tap water had an influence on growth on the early life stages of zebrafish.
Aniline Compounds↗
[MR urography with the T2-weighted turbo-spin-echo sequence].
Tumor-induced dilatation of the urinary tract is difficult to diagnose in the distal part of the ureter, including the stenosis, by ultrasound and X-ray. Often on account of renal insufficiency and allergy, i.v.-contrast media cannot be used. The present study should show the suitability of fast T2-weighted (turbo-) spin-echo sequences (T2-TSE) for MR-urography (MRU). Seven patients (62.3 +/- 6.1 years) were examined in the coronal plane with T2-TSE sequence (TR = 4500 ms, TE = 160 ms) and an MRU was calculated by using the MIP method (maximal intensity projection). This technique enabled urogram-like morphological representation of dilated urinary tract including stenosis in 6 of 7 patients. Assuming a high magnetic field homogeneity, MRU by using a T2-TSE-sequence, without i.v.-contrast media administration, can visualize the urinary tract dilatation and localize tumor-induced stenosis.
Adult↗
Ruv and recG genes and the induced precise excision of Tn10 in Escherichia coli.
Induction of precise excision of Tn10 by UV or mitomycin C (MMC) is dependent on the expression of the SOS system. Ruv mutants of Escherichia coli, which are defective in DNA repair and recombination, showed diminished frequencies of both spontaneous and UV- or MMC-induced excision of Tn10 inserted in gal. RecG mutants, which are also defective in DNA repair and recombination, showed decreased induction of Tn10 excision with MMC, but not after UV treatment. A recG ruv double mutant showed a greater decrease in induction of excision with MMC than either single mutant. One can speculate that the Ruv proteins, which are known to be involved in the resolution of Holliday junctions, might also be involved in the resolution of putative intermediates generated during the precise excision of Tn10. RecG protein, whose function partially overlaps those of Ruv proteins, might also have some role in this process.
Bacterial Proteins↗
Pathogenicity in mice of Staphylococcus aureus mutants deficient in exoprotein synthesis.
Twelve mutants were isolated from a Staphylococcus aureus strain derived from bovine mastitis after mutagenesis by ultraviolet light. These mutants were found to be deficient for several characteristics such as production of most exoproteins and had altered phage type and/or colonial morphology in serum-soft agar medium. They also differed in virulence when assayed in mice by intraperitoneal administration; the ratio of the LD50 of the mutants vs. that of the parental strain ranged from 1 to 123. The different virulence of the mutants could not be associated with lack of production of exoproteins or altered colonial morphology. On the other hand, a clear correlation was evidenced between lowered virulence and slower growth rate at 37 degrees C. Three mutants were assayed in the mouse mastitis model. One of them, which was about 40 times less virulent when assayed by intraperitoneal administration, induced a histopathological lesion similar to that produced by the parent strain; the other two mutants, which were about 70 to 120 times less virulent by intraperitoneal administration, induced only a very slight lesion. Mice were vaccinated by the intraperitoneal route with two of the less virulent mutants; the LD50 in the vaccinated mice that were challenged with the parental strain increased 11 to 14 times compared with that for the unvaccinated mice.
Animals↗
Characterization of a Tn925-induced mutant of Staphylococcus aureus altered in exoprotein production.
An insertional mutant was isolated from a bovine Staphylococcus aureus strain after membrane-mating with a Streptococcus faecalis strain carrying conjugative plasmid pCF10::Tn925. This mutant, designated RC128, showed enhanced production of alpha-hemolysin and proteases and decreased production of coagulase, extracellular protein A, DNase, lipase and delta-hemolysin. No difference was found in the production of beta-hemolysin. Both, Southern blot analysis and transfer of the pleiotropic mutant phenotype by transduction, indicated that the mutation was originated from a single insertion of transposon Tn925. The LD50 determined by intraperitoneal administration in mice showed that mutant RC128 was slightly less virulent than its parental strain.
Animals↗
RecN SOS gene and induced precise excision of Tn10 in Escherichia coli.
A mutant defective in the induced excision of Tn10 was isolated by decreased papillation on MacConkey-galactose plates with mitomycin C. The mutation involved was characterized as recN by genetic mapping and complementation. This mutant, as well as a previously characterized recN mutant (recN262), showed a markedly decreased frequency of excision of Tn10 after treatment with UV or mitomycin C. These observations indicate that recN is involved in the induced excision of Tn10.
DNA Repair↗
Deoxyribonucleic acid content and survival rates of patients with transitional cell carcinoma of the bladder.
In 127 patients with urothelial carcinoma of the bladder the ploidy, deoxyribonucleic acid (DNA) heterogeneity and counts of cell cycle phases in the tumor were analyzed by means of single cell DNA cytophotometry with the intention of finding new prognostic factors in addition to those already known (stage and grade). Patients were followed for 1 to 9 years. The results of the DNA analyses were related to the tumor categories, histopathological grading of the tumor and clinical course. Tumors were histologically classified as grade 1--DNA frequency peaks in the diploid range, grade 2--heterogenous DNA distribution patterns, and grade 3-73% aneuploid and 27% tetraploid DNA values. The proliferation rate of the tumor cells was statistically greater in cases of histological grades 2 and 3 malignancy than in grade 1 malignancy. There was also a positive correlation between tumor stage and DNA ploidy. The cell lines were aneuploid in 38% of the patients with stage pT1, 64% with stage pT2 and almost 85% with stage pT3 tumors. A significant correlation was found between the results of DNA cytophotometry and the clinical course of the disease. Patients with diploid tumor cell lines had no metastases and no local tumor progression for up to 9 years, whereas patients with multiple aneuploid tumor cell lines suffered recurrence and local tumor progression within 6 to 36 months. On the average, the patients died of the tumors 26 months after primary diagnosis. The difference in tumor recurrence and in tumor progression between patients with aneuploid and diploid tumors was highly significant (p < 0.001). The prognosis for patients with grade 1 tumors is good, whereas it is unfavorable in the case of grade 3 tumors. For these 2 groups DNA ploidy affords no additional prognostic information. Grade 2 tumors, on the other hand, are heterogeneous in respect to DNA ploidy, although they exhibit the same degree of histomorphological differentiation. These tumors can be subclassified as aneuploid (biologically aggressive) and diploid or tetraploid (biologically less aggressive). In terms of multivariate Cox regression analysis, DNA ploidy compared with grade and tumor stage was the strongest predictor of survival.
Adult↗
[Osteoplastic bone metastases in prostatic carcinoma: magnetic resonance tomography and bone marrow scintigraphy].
MRI of the vertebral column was performed in 28 patients with histologically confirmed prostate carcinoma. Besides routine spin-echo sequences all patients were examined with gradient-echo sequences using the chemical shift mode. In addition, in all patients bone marrow scintigraphy (BMS) was performed, and all results were compared with routine bone scan (BS). In our study BMS was not superior to bone scan. In contrast, MRI scan revealed solitary metastases in two patients with negative BS and BMS. Osteoplastic metastases showed a contrast enhancement in the MRI and could be distinguished from benign alterations.
Aged↗
Characterization of a Tn551-mutant of Staphylococcus aureus defective in the production of several exoproteins.
A Tn551 insertional pleiotropic mutant defective in the production of several exoproteins was isolated from Staphylococcus aureus 196E and characterized. The pleiotropism of the mutant was due to a single insertion of the transposon as evidenced by Southern blot hybridization and by the transfer of its phenotype by transduction to S. aureus ISP479. The mutants showed diminished or null levels of alpha- and beta-hemolysis, DNase, coagulase, and protein A in the supernatants of broth cultures. Production of proteases, lipase, staphylokinase, or enterotoxin A was not modified. The mutants did synthesize the cell-bound form of protein A and also the extracellular form of this protein coded by pRIT11, which lacks the COOH-terminal segment of the molecule. These observations suggest that the sae locus does not involve a positive regulatory gene acting at the transcriptional level. The phenotype of the mutant was different from that of other insertional mutants affecting exoprotein synthesis, such as agr, xpr, or sar. This new mutation has been designated sae (for S. aureus exoprotein expression).
Bacterial Proteins↗
Role of contralateral kidney in the maintenance of two-kidney, one-clip renovascular hypertension.
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Animals↗
Effect of mutations in SOS genes on UV-induced precise excision of Tn10 in Escherichia coli.
UV treatment increases the frequency of Tn10 precise excision from different sites of the Escherichia coli chromosome. UV induction of Tn10 excision is not evidenced in a lexA3 (ind-) mutant carrying either a recA+ or a recA730 allele. High levels of RecA synthesized by a recA+ gene not repressible by LexA do not relieve the non-inducibility of Tn10 excision in a lexA3 (ind-) background. This indicates that the expression of an SOS gene different from recA is necessary for the induction of Tn10 excision. In contrast to UV induction of point mutations, this induction does not depend on a functional umuC gene since umuC::Tn5 mutants show increased levels of Tn10 excision from leu, thr or gal after irradiation. MucAB+ plasmid pKM101 which renders cells more UV-mutable for point mutations decreases UV-induced Tn10 excision. These results show that UV-induced Tn10 precise excision requires SOS induction and that it involves a pathway different from point mutagenesis.
Bacterial Proteins↗
Effect of different local and systemic therapy upon urinary bladder cytology.
1,900 cytological analyses of urine and bladder washings were made in 127 patients with urothelial bladder carcinomas before, during and after therapy. Following transurethral resection, all patients were treated by intravesical instillation of mitomycin C or thiotepa. Because of a locally advanced bladder carcinoma, 26 patients who were not candidates for radical cystectomy were given an integrated treatment of radiotherapy and chemotherapy. Intravesical administration of mitomycin C and thiotepa as well as integrated radiotherapy and chemotherapy induce a variety of cytological effects (toxic and/or metabolical) which may lead to cytological misinterpretations in the follow-up. DNA measurements by means of single-cell spectrocytophotometry show that the cytological effects induced by the above-mentioned therapies are not accompanied by an increase in the nuclear DNA content. It is concluded that the knowledge of these induced effects is mandatory for a correct interpretation of urinary cytology in the follow-up. Considering these effects and the clinical history, bladder carcinoma recurrences during and after intravesical chemotherapy or integrated radiotherapy and chemotherapy may be detected early by urinary cytology in the hands of an experienced cytopathologist or urologist. Furthermore, alterations of the urinary cytology occur after systemic application of cyclophosphamide and under immunosuppressive therapy.
Administration, Intravesical↗
Development and evaluation of a reagent carrier with a new reaction sequence for the determination of creatinine in blood, plasma, serum and urine.
After a short outline of the history of creatinine determination methods we describe the development of a dry-reagent-carrier system for the reflometric determination of the creatinine concentration in blood, plasma, serum and urine (Reflotron Creatinine (new)). The method is based on a sequence of enzymatically catalyzed reactions producing H2O2, but which in contrast to the previously used procedure do not lead to the formation of creatine as an intermediate. Hence, pretreatment of sample material to eliminate endogenous creatine is no longer necessary. In the indicator reaction, use is made of an imidazole derivative as the chromogen. The dye formed in the presence of peroxidase can be measured by reflectance photometry beyond the long-wave absorption bands of haemoglobin and bilirubin at 642 nm. We present in detail the results of the multicentre evaluation of the analytical properties of this new test principle. The data obtained show that Reflotron Creatinine (new) correlates well with the routine method Creatinine PAP, which was used as a comparison method, with respect to accuracy and precision and even surpasses it with respect to specificity. Advantages over the first generation of Reflotron Creatinine are: shorter reaction time, longer stability of the reagent carrier, no interference by bilirubin and reduced interference by haemoglobin.
Blood Chemical Analysis↗
[The long-term toxicity of polychemotherapy in successfully treated testicular carcinoma].
Of 55 patients with testicular cancer, treated by combination chemotherapy including cisplatin, 21 (mean age 35 [21-51] years) were reexamined for late sequelae of the chemotherapy 1-9 years later. No patient had a recurrence or second malignancy. They all had normal renal function (renal sequence scintigraphy; creatinine clearance). Seven of 20 patients had a polyneuropathy, nine of 18 had high-tone hearing loss. Two patients became fathers after treatment. In nine of 20 patients the serum concentration of follicle-stimulating hormone was raised to above 20 mU/ml, evidence of germ-cell damage. Six of 13 patients had an abnormal ejaculation following retroperitoneal lymphadenectomy or excision of a residual tumour. There was no evidence of any life-limiting toxicity of the chemotherapy.
Adult↗
Deletion and insertion mutants of HBsAg particles.
We have found previously that hybrid 22-nm HBsAg particles can be created by insertion of short antigenic sequences into the HBV major envelope protein. We have now performed a detailed deletion mutagenesis of the S gene of HBV encoding HBsAg. Deletion of the 51 C-terminal amino acids including most of the third and all of the fourth hydrophobic domain of the S protein did not affect particle assembly and secretion. However, secretion of 22-nm particles was abolished by minor deletions in the N-terminal region. Insertion and deletion/substitution mutants carrying a poliovirus epitope at the N-terminus and the preS1 region at the C-terminus have been characterized.
DNA Mutational Analysis↗
Transitional cell carcinoma of the renal pelvis and ureter: prognostic relevance of nuclear deoxyribonucleic acid ploidy studied by slide cytometry: an 8-year survival time study.
In 72 patients with urothelial carcinoma of the renal pelvis or ureter the ploidy, deoxyribonucleic acid (DNA) heterogeneity and counts of cell cycle phases in the tumor were analyzed by means of single cell DNA cytophotometry with the intention of finding new prognostic factors in addition to those already known (stage and grade). Followup ranged from 1 to 8 years. The results of the DNA analyses were related to the tumor categories, histopathological grading of the tumors and clinical course. Malignancy grade 1 tumors showed DNA frequency peaks in the diploid range, while tumors assessed as malignancy grade 2 showed heterogeneous DNA distribution patterns. Malignancy grade 3 tumors exhibited 71% aneuploid and 29% tetraploid DNA values. The proliferation rate of the tumor cells was statistically significantly higher in malignancy grades 2 and 3 than in malignancy grade 1. The prognosis for grade 1 tumors is good, whereas it is unfavorable in the case of grade 3 tumors. For these 2 groups (patients with grades 1 and 3 tumors) DNA ploidy affords no additional prognostic information. Grade 2 tumors, on the other hand, are heterogeneous in respect to DNA ploidy although they exhibit the same histomorphological degree of differentiation. These tumors can be subclassified as aneuploid (biologically aggressive) and diploid or tetraploid (biologically less aggressive) tumors. There was also a positive correlation between T category and DNA ploidy. The cell lines were aneuploid in 38% of the patients with stage T1 tumors, 56% with stage T2 tumors and almost 85% with stage T3, N+ tumors. A significant correlation was found between the results of DNA cytophotometry and the clinical course of the disease. Patients with diploid tumor cell nuclei had no metastases and no local tumor progression for up to 8 years, whereas patients with aneuploid tumor cell nuclei suffered metastasis and local tumor progression within 24 to 36 months. The patients died of the tumor 36 months after primary diagnosis on the average. The determination of DNA ploidy, tumor heterogeneity and tumor cell proliferation by means of DNA cytophotometry affords valuable clues as to prognosis.
Adult↗