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Biomedical subjects

B Persson

Publications and source records attributed to B Persson.

At least 37 records · Page 2Linked to original sources
PubMed1992

Fetal scalp and umbilical artery blood lactate measured with a new test strip method.

OBJECTIVE: To compare the measurement of lactate in fetal scalp and umbilical artery blood by a new dry reagent strip method with a commercially available enzymatic method using plasma (Monotest). DESIGN: Comparative study. SUBJECTS: Fetal scalp blood samples were obtained during labour from 24 fetuses and umbilical artery blood samples were obtained at birth in a further 51 deliveries. RESULTS: The concentration of lactate in scalp and umbilical artery blood measured by the reagent strip method correlated well (r = 0.94, P less than 0.001 and 0.95, P less than 0.001 respectively) with the enzymatic plasma method. The paper strip method tended to give lower readings than the enzymatic method when the fetal haematocrit was greater than or equal to 50%. CONCLUSIONS: The new dry reagent strip method which takes only 1 min to carry out and requires only 20 microliters of blood seems to be handy and reliable. This system provides a convenient and rapid test for measuring fetal blood lactate.

Evaluation Studies as Topic↗
PubMed1992

Binding of dietary cobalt to sarcoplasmic reticulum proteins.

It has previously been shown that cobalt accumulates in the myocardium of rats, mainly the sarcoplasmic reticulum (SR) and the mitochondrial inner membrane. In order to investigate the mode of accumulation of cobalt in the SR, rats were given a dietary cobalt supplementation of 40 mg of CoSO4 x 7H2O kg-1 body wt, after which the rats were sacrificed and the sarcoplasmic reticulum was isolated. The SR proteins were subjected to analysis by polyacrylamide gel electrophoresis followed by protein staining and determination of the content of cobalt in each protein band. The major cobalt-binding protein was found to have a molecular weight of about 100,000; a 200,000 molecular weight protein was also found to bind cobalt, although less extensively. These results suggest that cobalt is bound to the monomeric and dimeric forms of Ca(2+)-ATPase in the SR of the myocardium.

Animals↗
PubMed1992

Structural characterization of rabbit brain ubiquitin.

Ubiquitin has been isolated and purified from rabbit brain using gel permeation and reverse-phase high-performance liquid chromatography. The 76-residue protein exhibits one difference towards a murine form, is identical to other characterized vertebrate ubiquitins, and confirms an extensive conservation of the ubiquitin structure. No positional microheterogeneities were detectable between two sub-forms.

Amino Acid Sequence↗
PubMed1992

Can somatostatin prevent injection pancreatitis after ERCP?

In a double-blind randomized study, 30 patients received somatostatin infusion during ERCP and 30 patients placebo with the aim of evaluating whether somatostatin can reduce the incidence of injection pancreatitis. S-amylase, U-amylase and S-lipase were evaluated before, during and after (up to 48 hours) ERCP. C-peptide was also determined as a marker of the function of the endocrine pancreas. While no statistically significant effect of somatostatin in terms of amylase and lipase was to be found, somatostatin did significantly decrease c-peptide levels in plasma, indicating that the peptide inhibited beta-cell secretion. About 40% of patients in the somatostatin group and about 50% in the placebo group showed signs of injection pancreatitis (elevated levels of enzymes) and in both groups there are patients with clinically apparent pancreatitis.

Aged↗
PubMed1991

Characteristics of short-chain alcohol dehydrogenases and related enzymes.

Different short-chain dehydrogenases are distantly related, constituting a protein family now known from at least 20 separate enzymes characterized, but with extensive differences, especially in the C-terminal third of their sequences. Many of the first known members were prokaryotic, but recent additions include mammalian enzymes from placenta, liver and other tissues, including 15-hydroxyprostaglandin, 17 beta-hydroxysteroid and 11 beta-hydroxysteroid dehydrogenases. In addition, species variants, isozyme-like multiplicities and mutants have been reported for several of the structures. Alignments of the different enzymes reveal large homologous parts, with clustered similarities indicating regions of special functional/structural importance. Several of these derive from relationships within a common type of coenzyme-binding domain, but central-chain patterns of similarity go beyond this domain. Total residue identities between enzyme pairs are typically around 25%, but single forms deviate more or less (14-58%). Only six of the 250-odd residues are strictly conserved and seven more are conserved in all but single cases. Over one third of the conserved residues are glycine, showing the importance of conformational and spatial restrictions. Secondary structure predictions, residue distributions and hydrophilicity profiles outline a common, N-terminal coenzyme-binding domain similar to that of other dehydrogenases, and a C-terminal domain with unique segments and presumably individual functions in each case. Strictly conserved residues of possible functional interest are limited, essentially only three polar residues. Asp64, Tyr152 and Lys156 (in the numbering of Drosophila alcohol dehydrogenase), but no histidine or cysteine residue like in the completely different, classical medium-chain alcohol dehydrogenase family. Asp64 is in the suggested coenzyme-binding domain, whereas Tyr152 and Lys156 are close to the center of the protein chain, at a putative inter-domain, active-site segment. Consequently, the overall comparisons suggest the possibility of related mechanisms and domain properties for different members of the short-chain family.

Alcohol Dehydrogenase↗
PubMed1991

Lipoprotein lipases and vitellogenins in relation to the known three-dimensional structure of pancreatic lipase.

A 106-residue region of high similarity between lipoprotein/pancreatic/hepatic lipases and Drosophila vitellogenins encompasses four beta-strands with all residues but one strictly conserved or conservatively replaced between the structures, and enclosing the putative active site Ser-152. The properties suggest a common folding pattern but the region probably does not function as an 'interface recognition site' in the lipases, although it might well bind fatty acid esters of ecdysteroids or single lipid molecules in the vitellogenins. C-terminally of this 106-residue region, a surface loop ('flap') covers the active site. No residue within this loop is conserved through all lipases, but adjacent segments exhibit 60-70% residue identity. Hepatic and lipoprotein lipases probably hydrolyze both soluble and emulsified substrates at the same site. They lack residues corresponding to a second active site postulated in pancreatic lipase to account for hydrolysis of soluble substrates. In addition, due to structural differences the flap could prevent entry of soluble substrate molecules into the active site of pancreatic lipase.

Amino Acid Sequence↗
PubMed1991

Flow-force relationships during energy transfer between mitochondrial proton pumps.

The effect of inhibitors of proton pumps, of uncouplers and of permeant ions on the relationship between input force, delta mu H+, and output flows of the ATPase, redox and transhydrogenase H(+)-pumps in submitochondrial particles was investigated. It is concluded that: (1) The decrease of output flow of the transhydrogenase proton pump, defined as the rate of reduction of NADP+ by NADH, is linearily correlated with the decrease of input force, delta mu H+, in an extended range of delta mu H+, independently of whether the H(+)-generating pump is the ATPase or a redox pump, or whether delta mu H+ is depressed by inhibitors of the H(+)-generating pump such as oligomycin or malonate, or by uncouplers. (2) The output flows of the ATPase and of the site I redox H(+)-pumps exhibit a steep dependence on delta mu H+. The flow-force relationships differ depending on whether the depression of delta mu H+ is induced by inhibitors of the H(+)-generating pump, by uncouplers or by lipophilic anions. (3) With the ATPase as H(+)-consuming pump, at equivalent delta mu H+ values, the output flow is more markedly inhibited by malonate than by uncouplers; the latter, however, are more inhibitory than lipophilic anions such as ClO4-. With redox site I as proton-consuming pump, at equivalent delta mu H+ values, the output flow is more markedly inhibited by oligomycin than by uncouplers; again, uncouplers are more inhibitory than ClO4-. (4) The results provide further support for a delocalized interaction of transhydrogenase with other H(+)-pumps.

Adenosine Triphosphate↗
PubMed1991

Functionally important regions of glucose-6-phosphate dehydrogenase defined by the Saccharomyces cerevisiae enzyme and its differences from the mammalian and insect forms.

The primary structure of Saccharomyces cerevisiae glucose-6-phosphate dehydrogenase has been determined. It consists of 503 amino acid residues, with an acetyl-blocked N-terminus. The structure shows equally extensive differences from the corresponding mammalian and fruit fly enzymes (52% residues non-identical). Residues conserved in all the forms constitute about 40% of the structures and include two histidines. One of these (His200 in the numbering of the rat enzyme) occurs in a 10-residue conserved segment, including the reactive Lys204, probably related to substrate binding. Two segments with conserved Gly-Xaa-Xaa-Gly-Xaa-Xaa-Gly/Ala pattern constitute possibilities for the coenzyme-binding site. One is N-terminally located (positions 37-43) with two conserved arginine residues nearby (positions 56 and 71), of interest for phosphate binding. The other (positions 241-247) is in a middle region, with many residue identities, containing the conserved residues Arg256 and His264.

Amino Acid Sequence↗
PubMed1991

Different segment similarities in long-chain dehydrogenases.

Long-chain dehydrogenases were scrutinized for common patterns. Overall molecular similarities are not discerned, in contrast to the situation for several short-chain and medium-chain dehydrogenases, but coenzyme-binding segments are discernible. Species variants of glucose-6-phosphate dehydrogenase reveal about 20% strictly conserved residues, grouped into three segments and supporting assignments of sites for coenzyme-binding and catalysis. Glycine is overrepresented among the residues conserved, typical of distantly related proteins. Two of the enzymes within the pentose phosphate pathway reveal a distant similarity of interest for further evaluation, between a C-terminal 178-residue segment of glucose-6-phosphate dehydrogenase and the N-terminal part of 6-phosphogluconate dehydrogenase.

Amino Acid Sequence↗
PubMed1991

Cytogenetic analysis of 33 basal cell carcinomas.

Cytogenetic analysis of short-term cultures from 33 basal cell carcinomas (BCC), a type of neoplasm for which no previous karyological data exist, revealed clonal chromosome aberrations, all of them different, in 8 tumors. In 2 cases, 2 cytogenetically unrelated clones were detected, suggesting a multicellular origin in at least a subset of BCC. A remarkably high level of nonclonal structural rearrangements, mostly in the form of seemingly balanced translocations, was found in 23 tumors; namely, in 6 of 8 BCC with clonal karyotypic abnormalities and in 17 of 25 without. It is possible that some of these aberrations represent additional neoplastic clones, thus indicating an even higher level of cytogenetic heterogeneity in BCC. We think that the most likely interpretation of the results is that BCC may have a multicellular origin, reflecting field cancerization of the skin. During subsequent tumor development, the selection pressure narrows down the number of clones that infiltrate the surrounding tissue. The finding by karyotypic analysis of some apparently monoclonal, some polyclonal BCC, may reflect that different tumors have been examined at different points in the clonal evolution of the neoplastic cells.

Aged↗
PubMed1991

Mortality pattern among pulp and paper mill workers in Sweden: a case-referent study.

The mortality pattern among Swedish pulp and paper mill workers was evaluated in a case-referent study encompassing 4,070 men decreased during the period 1950-1987. The subjects were identified from the register of deaths and burials in six parishes. A significantly increased mortality was seen for diabetes mellitus and for secondary tumors of the lung and liver among the pulp and paper mill workers. Indications of excess risks were also found for obstructive lung disorders, pulmonary emboli, accidents, and pneumonia, as well as for malignant lymphomas, leukemias, and cancer of the pancreas and stomach. In the only parish where a sulfite process was exclusively used, cancer of the digestive tract and especially of the rectum was found to be in excess. Except for this parish, the sulfate process predominated in the plants included. The mortality pattern found in this study is in reasonable agreement with findings in various studies from this type of industry.

Adult↗
PubMed1991

Antihypertensive effects of chronic 5-hydroxytryptamine (5-HT2) receptor blockade with irindalone in the spontaneously hypertensive rat.

The present study was conducted to evaluate the antihypertensive effects of irindalone, a potent 5-HT2-receptor blocking agent with weak alpha 1-adrenoceptorblocking properties. Young spontaneously hypertensive rats (SHR) received irindalone in the food (daily intake estimated to 10 mg/kg) for 10 weeks and older SHR received irindalone subcutaneously for 2 weeks (3 mg/kg/day by osmotic pump). The indirect systolic blood pressure was measured each week (tail plethysmography) and at the end of the intervention periods the direct intraarterial blood pressure was measured in conscious rats. Subsequently a dose-response curve of pressor responses to phenylephrine was constructed in pithed rats. Chronic oral treatment with irindalone reduced the development of hypertension but influenced neither body weight nor heart weight. The subcutaneous treatment with irindalone reduced the blood pressure in relatively older SHR compared with controls. Pressor responses to phenylephrine were antagonized in rats receiving oral treatment. However, during subcutaneous treatment with irindalone the dose-response curve to phenylephrine was not influenced, suggesting that the blood pressure reduction was not directly related to a concomitant alpha 1-adrenoceptor blockade. These results demonstrate that irindalone effectively reduces the blood pressure in SHR and that no tolerance develops to its antihypertensive effects. Since the blood pressure reduction, at least following subcutaneous treatment, was not directly related to a concomitant alpha 1-blockade, it is suggested that the 5-HT2-receptor blockade may be of relevance for the antihypertensive effect.

Adrenergic alpha-Antagonists↗
PubMed1991

Variations of common bile duct diameter after endoscopic sphincterotomy.

Diameters of the common bile duct (CBD) and common hepatic duct (CHD) were measured before and after endoscopic sphincterotomy (EPT) in 100 patients. There was a significant reduction of the lumen diameter in both the CBD and CHD (p less than 0.01) after EPT. A comparison between 32 patients without symptoms (such as pain, residual stones, and elevated levels of liver enzymes) and 19 patients with remaining symptoms after EPT, showed a statistically significant reduction in both CBD and CHD diameters (p less than 0.001) in the former group, and no statistically proven changes in the diameters in the latter group, since a change of less than 1.5 mm was not considered significant. Therefore, the absence of a reduction or a dilatation of the diameter of the CBD after EPT may suggest that these patients may have persisting complaints after EPT. Measurements on models (phantoms) show that body position of the patient during endoscopic retrograde cholangiopancreatography (ERCP) has little and negligible influence on the measured diameters of the CBD and CHD.

Aged↗
PubMed1991

Relation of size and number of common duct calculi to success of sphincterotomy and stone extraction.

Endoscopic sphincterotomy (ES) for common bile duct calculi (CBDC) was performed on 210 patients, and 190 of these were available for follow-up. One hundred seventy-three patients (91%) were successfully treated with ES alone, whereas 17 patients required operation. Stone size was of importance to attain complete clearance of CBDC as larger stones (greater than 1 cm) were significantly more difficult to extract endoscopically than smaller stones (p less than 0.01). A comparison between patients with one CBDC and those with two or more show a statistically significant difference in that the former group is easier to treat successfully (p less than 0.001).

Adult↗
PubMed1991

A circular dichroism study of mitochondrial transhydrogenase from beef heart.

This paper describes a circular dichroism (CD) spectroscopy study of purified proton-pumping nicotinamide nucleotide transhydrogenase from beef heart. The CD spectrum obtained was used to estimate the content of secondary structures of the purified enzyme and suggests the presence of 40-45% alpha-helical structure and long, possibly membrane-spanning alpha-helices. The spectrum was essentially unaffected by the absence or presence of transhydrogenase substrates, suggesting that the catalytic and proton-translocating activities of the enzyme occur without major rearrangements at the level of secondary structures.

Animals↗