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Biomedical subjects

D Boehme

Publications and source records attributed to D Boehme.

11 recordsLinked to original sources
PubMed1992

Clinicopathological assessment of gastric biopsy samples of patients with Helicobacter pylori infection--metronidazole resistance and compliance problems in the United Arab Emirates.

The significance of Helicobacter pylori (HP) infection was assessed prospectively in forty-two patients with dyspepsia using histological, bacteriological and biopsy urease techniques. Thirty-eight patients (90.5%) were positive for HP infection and were treated with bismuth subcitrate (De Nol), tinidazole and doxycycline. HP was present in the antrum, corpus, fundus, duodenum and gastric juice in 36, 26, 23, 2 and 2 patients respectively (p < 0.01, X2 test). Histological assessment yielded more positive identifications of HP than the urease test (36 vs 28 positive cases, p < 0.01, McNemar's X2 test), while histology and bacteriology were virtually identical (38 vs 37 of 41 pairs, p > 0.5, X2 test). There was a good correlation between bacterial and polymorphonuclear leucocyte (PMNL) counts per high power field (r = 0.8; p < 0.001; n = 34 pairs). There was resistance to metronidazole in 10 out of 16 isolates, but no resistance was recorded against tetracycline (p < 0.001, X2 test). Among the sixteen patients who attended follow-up endoscopy, there was clinical improvement and no evidence of HP in 5 individuals (31.25%). One patient had amelioration of his symptoms, 5 experienced no change and in 5 their symptoms became worse. Metronidazole resistance may be one of the important factors in the United Arab Emirates and elsewhere.

Adolescent↗
PubMed1991

Non-union of fractures of the mid-shaft of the clavicle. Treatment with a modified Hagie intramedullary pin and autogenous bone-grafting.

We reviewed a series of fifty patients who had a non-union of a fracture of the clavicle. Twenty-one patients (42 per cent) who had a symptomatic non-union of the middle of the shaft of the clavicle were treated with open reduction, internal fixation with a modified Hagie intramedullary pin, and autogenous bone-grafting, and those patients form the basis for the report. The average duration of follow-up was thirty-five months (range, five months to eleven years). Healing occurred in twenty (95 per cent) of the twenty-one patients. Intramedullary fixation has several advantages compared with other treatments, such as fixation with a plate and screws. It can be performed through a cosmetically acceptable incision in the Langer line; less dissection of the soft tissues is needed; and, after healing, the pin can be removed through a small incision under local anesthesia.

Adult↗
PubMed1978

Fructose-1,6-diphosphatase: a cellular site of hyperbaric oxygen toxicity.

The growth-inhibitory effect of 4.2 atm of hyperbaric oxygen for Escherichia coli was strongly influenced by available nutrients. A pattern of protection was achieved with various carbohydrate intermediates which was consistent with oxygen-induced poisoning of fructose-1,6-diphosphatase and of enzymes required in the pentose shunt and for converting galactose into glucose. Two of these sites have not been investigated further, but direct evidence was obtained that purified fructose-1,6-diphosphatase was inactivated in vitro by superoxide anion, but not by molecular oxygen at hyperbaric pressure (4.2 atm). Poisioning of fructose-1,6-diphosphatase by metabolically generated oxygen radicals, such as superoxide ion, would have deleterious effects for E. coli in media where synthesis of glucose by reverse glycolysis is required, and presumably for cells of higher organisms, including man.

Atmospheric Pressure↗
PubMed1978

Intrahepatic pigment and crystal forms in patients with cerebrotendinous xanthomatosis (CTX).

Liver specimens from two patients with cerebrotendinous xanthomatosis revealed intracellular inclusions that appeared either as amorphous pigment or in a crystalloid form. The pigment was usually found in assoication with the smooth endoplasmic reticulum and occasionally free floating in the cytosol. The chemical nature of these inclusions has not yet been determined. However, the accumulation of such material may indicate the presence of nonmetabolizable bile alcohols resulting from a defect in bile acid synthesis.

Adult↗
PubMed1976

Distinct steps in the specific binding of tRNA to aminoacyl-tRNA synthetase. Temperature-jump studies on the serine-specific system from yeast and the tyrosine-specific system from Escherichia coli.

The kinetics of the interaction of tRNASer and seryl-tRNA synthetase from yeast as well as of tRNATyr and tyrosyl-tRNA synthetase from Escherichia coli have been investigated by temperature-jump experiments. It could be shown that complex formation proceeds in two distinct steps. This was demonstrated for both the first and the second binding site. The two-step mechanism was deduced from the characteristic concentration dependence of the relaxation times. Seryl-tRNA synthetase recombines with the first tRNA to form an intermediate complex (kI12, kI21), which is transformed in a fast reaction to the final 1:1 complex (kI23, kI32). At pH 7.2 with 0.1 M KCl the rate constants are: kI12 = 2.7 X 10(8) M-1 S-1; kI23, kI32). At pH 7.2 with 0.1 M KCl the rate constants are: kI12 = 2.7 x 10(8) M-1 S-1; kI21 = 220 S-1; kI23 = 760 S-1; kI32 = 330 S-1. The 1:1 complex can bind a second tRNA. At pH 7.2 without added salt the rate constants are: KII2 = 0.9 X 10(8) M-1 S-1; kII21 = 270 S-1; kII23 = 120 S-1; kII32 = 1250 S-1. The tyrosine-specific system behaves very similarly to the serine-specific system. Data are given for pH 7.2 (pH 6.0) for the binding of the second tRNA: kII12 = 1 X 10(8) (2.5 X 10(8)) M-1 S-1; kII21 = 470 (170) S-1; kII23 = 150 (530) S-1; kII32 = 1540 (720) S-1. The kinetic results are discussed in terms of their relevance to the recognition process and their relation to the anticooperative binding behaviour of tRNA to synthetase.

Amino Acyl-tRNA Synthetases↗
PubMed1975

Equivalent and non-equivalent binding sites for tRNA on aminoacyl-tRNA synthetases.

Complexes between tRNAPhe (yeast), tRNASer (yeast) and tRNATyr (Escherichia coli) and their cognate aminoacyl-tRNA synthetases have been studied by sedimentation velocity runs in an analytical ultracentrifuge. The amount of complex formation was determined by the absorption and the sedimentation coefficients of the fast-moving boundary in the presence of excess tRNA or excess synthetase respectively. The same method has been applied to unspecific combinations of tRNAs and synthetases. Inactive material of tRNA or synthetase does not influence the results. 1. Two moles of tRNAPhe can be bound to one mole of phenylalanyl-tRNA synthetase with a binding constant greater than 10(6) M-1. The binding constants for both tRNAs are very similar; the binding sites are independent of each other. Omission of Mg2+ does not prevent binding. 2. Two moles of tRNASer can be bound to one mole of Seryl-tRNA synthetase; the binding of the first and second tRNA is non-equivalent, K1 greater than 10(6) M-1, K2 is determined to be 1.3 X 10(5) M-1 at pH 7.2. Omission of Mg2+ prevents complex formation. 3. Tyrosyl-tRNA synthetase behaves very similarly to seryl-tRNA synthetase. The binding constant for the weakly bound tRNA is 2.3 X 10(5) M-1 at pH 7.2, and 2.5 X 10(6) M-1 at pH 6.0. No complexes are observed in the absence of Mg2+. 4. Unspecific binding was only obtained with phenylalanyl-tRNA synthetase. It binds tRNASer (yeast), tRNAAla (yeast) and tRNATyr (E. coli) with a binding constant about 100 times lower compared to its cognate tRNA. The binding data are discussed with respect to the tertiary structure of the tRNAs, the subunit structure of the synthetases and the possible physical basis for the non-equivalence of binding sites.

Amino Acyl-tRNA Synthetases↗