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Biomedical subjects

H Blom

Publications and source records attributed to H Blom.

At least 37 records · Page 2Linked to original sources
PubMed1998

Elevated plasma levels of homocysteine in Parkinson's disease.

Significantly elevated plasma levels of homocysteine, but not cysteine and cysteinylglycine, were found in treated parkinsonian patients compared to controls. Elevated levels of homocysteine may be either caused by an unknown endogenous metabolic disturbance or by antiparkinsonian treatment, because no association to severity or duration of disease was found. Based on the results of this study one may speculate that homocysteine may be an independent risk factor for vascular disease in Parkinson's disease.

Aged↗
PubMed1997

A model assay to demonstrate how intrinsic factors affect diffusion of bacteriocins.

A rapid and simple method to elucidate how intrinsic factors in a given food product affect bacteriocin diffusion and efficacy is described. The basic idea of this assay is to help predict which bacteriocin or other inhibitory substance to select for a given product, where increased security towards specific microorganisms is wanted. In an agar plate model system the effect of five factors (number of indicator cells, pH and concentration of NaCl, agar and soy oil) on the diffusion of the bacteriocins sakacin A, sakacin P, pediocin PA-1, piscicolin 61 and nisin was studied. An experimental design permitting simultaneous evaluation of the effect of all factors was used. The results indicated that each bacteriocin has a characteristic intrinsic factor effect profile. However, pH and load of indicator cells affect all the bacteriocins.

Bacteriocins↗
PubMed1997

Addition of 2.5% lactate and 0.25% acetate controls growth of Listeria monocytogenes in vacuum-packed, sensory-acceptable servelat sausage and cooked ham stored at 4 degrees C.

A study of the inhibitory effects of propylparaben and of a combination of lactate and acetate against growth of Listeria monocytogenes in inoculated liquid medium, sliced servelat sausage and cooked ham, were performed using rifampicin resistant Listeria strains in inoculation experiments. A consumer acceptance test of products produced with and without the compounds was also performed. Propylparaben was found to be effective in a model liquid non-fat medium, but was without effect in the actual products. This illustrates the potential pitfalls in translating results from studies in liquid media to fat-containing food products. The combined inhibitory and sensory results showed that a mixture of 2.5% lactate and 0.25% acetate (w/w, calculated on the water phase), could be used to increase the margins of safety for sliced and spreadable vacuum-packed ready-to-eat cooked meat products stored for 4-6 weeks. In addition, strict control of temperature during production and storage is very important.

Acetic Acid↗
PubMed1997

Allergic rhinitis and inflammation: the effect of nasal corticosteroid therapy.

Topical corticosteroids have proved to be effective in the treatment of allergic rhinitis. The symptomatology of allergic rhinitis is considered to be the result of the accumulation and activation of inflammatory cells and cytokine release and hence the efficacy of corticosteroids is associated with their anti-inflammatory action. New advances in allergic inflammation now suggest that not only mast cells and eosinophils but also T-lymphocytes and antigen-presenting dendritic cells, play an important role in the inflammatory reaction. The effect of topical fluticasone propionate on cellular infiltration in the nasal mucosa is examined, with an emphasis on two studies performed in Rotterdam, The Netherlands. The cells influenced most by corticosteroid therapy were Langerhans' cells (antigen-presenting cells), which were almost completely eradicated, possibly resulting in diminished antigen presentation, and eosinophils. There was a reduction in the number of epithelial mast cells, but the number of T-lymphocytes only decreased following high doses of corticosteroid therapy or long-term treatment. However, T-lymphocyte function was influenced, as shown by the reduction in the T-helper2 (TH2)-related cytokines, interleukin (IL)-4 and IL-5. Topical corticosteroid therapy had no effect on the accumulation of macrophages. The reduction in antigen presentation, and the decrease in T-lymphocyte stimulation and cytokine production, may cause a reduced influx of eosinophils and other inflammatory cells, resulting in diminished symptomatology.

Administration, Topical↗
PubMed1996

Assessment of autonomic nerve function in acute intermittent porphyria; a study based on spectral analysis of heart rate variability.

OBJECTIVES: To assess the function of the autonomic nervous system in patients with acute intermittent porphyria by spectral analysis of the heart rate variability. DESIGN: A cross-sectional case-control study. SETTING: Patients were examined at the Primary Health Care Centre, Arjeplog and at Umeå University Hospital, where the controls were also examined. SUBJECTS: Twenty-three patients with acute intermittent porphyria verified by DNA analysis and 92 healthy controls were included. MAIN OUTCOME MEASURES: The mid-frequency band power after tilting was used to evaluate sympathetic function, and the high frequency band power during controlled breathing at 12 breaths min-1 and the mid-frequency band power during controlled deep breathing at 6 breaths min-1 were used to evaluate parasympathetic function. RESULTS: There was no evidence of sympathetic dysfunction in the patients. The mid-frequency band power during controlled deep breathing at 6 breaths min-1 was significantly (P = 0.02) lower in the patient group. CONCLUSIONS: Our findings indicate a parasympathetic dysfunction in patients with acute intermittent porphyria. This may be causally related to sudden cardiac death and the life-threatening arrhythmias which have been observed in this disorder.

Adult↗
PubMed1995

Dietary methionine does not reduce penetrance in curly tail mice but causes a phenotype-specific decrease in embryonic growth.

The mouse mutation, curly tail, has incomplete penetrance and variable expression. Approximately 60% of the mice have a curly tail (CT), from which up to 20% may have lumbosacral spina bifida. Approximately 40% are normal, with a straight tail (ST). We tested whether L-methionine, which reduces the penetrance of neural tube defects in the Axd mouse mutant, has beneficial effects in the curly tail mutant. A single injection of L-methionine (200-1600 mg/kg body wt) on d 9 of pregnancy had no effect on the embryos, whereas there was a minor increase in penetrance at the highest dose. Chronic supplementation of L-methionine via the drinking water (1554 mg.kg body wt-1.d-1) did not shift penetrance. However, it decreased the weight of d 13 embryos from ST dams but not of those from CT dams. This phenotype-specific difference in response was evident and most unexpected. Mice from curly tail and other inbred strains were subjected to an L-methionine loading test and serum homocysteine assay. The different strains varied in their basal serum homocysteine concentrations, and they had proportionate significant increases after L-methionine loading. In CT and ST mice, basal serum homocysteine concentrations as well as the levels after loading were similar to each other and intermediate in the range of the mice tested. We conclude that L-methionine does not reduce penetrance in the curly tail mouse and that this strain reflects no derangement in L-methionine handling.

Animals↗
PubMed1995

The effect of fluticasone propionate aqueous nasal spray on nasal mucosal inflammation in perennial allergic rhinitis.

Mast cell degranulation, and the subsequent recruitment of infiltrating inflammatory cells, such as eosinophils, into the nasal mucosa has long been considered the most important model to explain allergic rhinitis. Several studies show a decrease in the number of eosinophils and possibly also mast cells during local corticosteroid treatment. Over the last decade, a new model to explain allergic inflammation has evolved. In this model, Langerhans' cells and T-cells play an important role. Langerhans' cells possess a high affinity receptor for IgE. In patients with allergic rhinitis, allergen provocation results in stimulation of T-cells by the IgE-positive Langerhans' cells. The T-cells produce a number of cytokines which stimulate IgE production as well as the inflammatory reaction. The number of T-cells is not usually influenced by corticosteroid treatment; however, the function of the T-cells, shown by the spectrum of cytokines produced, is clearly influenced. The cells that are most dramatically affected by local corticosteroid treatment are the Langerhans' cells, which completely disappear during treatment. This decrease suggests that there is a reduction in antigen presentation. The subsequent decrease in T-cell stimulation may result in a reduction of the reactions that are dependent on T-cell-derived mediators.

Administration, Topical↗
PubMed1993

Cloning and nucleotide sequence of a gene from Lactobacillus sake Lb706 necessary for sakacin A production and immunity.

Sakacin A is an antilisterial bacteriocin produced by Lactobacillus sake Lb706. In order to identify genes involved in sakacin A production and immunity, the plasmid fraction of L. sake Lb706 was shotgun cloned directly into a sakacin A-nonproducing and -sensitive variant, L. sake Lb706-B, by using the broad-host-range vector pVS2. Two clones that produced sakacin A and were immune to the bacteriocin were obtained. A DNA fragment of approximately 1.8 kb, derived from a 60-kb plasmid of strain Lb706 and present in the inserts of both clones, was necessary for restoration of sakacin A production and immunity in strain Lb706-B. The sequence of the 1.8-kb fragment from one of the clones was determined. It contained one large open reading frame, designated sakB, potentially encoding a protein of 430 amino acid residues. Hybridization and nucleotide sequence analyses revealed that the cloned sakB complemented a mutated copy of sakB present in strain Lb706-B. The sakB gene mapped 1.6 kb from the previously cloned structural gene for sakacin A (sakA) on the 60-kb plasmid. The putative SakB protein shared 22% amino acid sequence identity (51% similarity if conservative changes are considered) to AgrB, the deduced amino acid sequence of the Staphylococcus aureus gene agrB. The polycistronic agr (accessory gene regulator) locus is involved in the regulation of exoprotein synthesis in S. aureus. Similar to the AgrB protein, SakB had some features in common with a family of transmembrane histidine protein kinases, involved in various adaptive response systems of bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Purification and amino acid sequence of sakacin A, a bacteriocin from Lactobacillus sake Lb706.

Sakacin A, a bacteriocin produced by Lactobacillus sake Lb706 and which inhibits the growth of Listeria monocytogenes, was purified to homogeneity by ammonium sulphate precipitation and ion-exchange, hydrophobic-interaction and reversed-phase chromatography. The complete amino acid sequence of sakacin A was determined by Edman degradation. The bacteriocin consisted of 41 amino acid residues and had a calculated M(r) of 4308.7, which is in good agreement with the value determined by mass spectrometry. The structural gene encoding sakacin A (sakA) was cloned and sequenced. The gene encoded a primary translation product of 59 amino acid residues which was cleaved between amino acids 18 and 19 to yield the active sakacin A. Sakacin A shared some sequence similarities with other bacteriocins.

Amino Acid Sequence↗
PubMed1992

A study of the interaction of omeprazole and warfarin in anticoagulated patients.

1. Thirty-five patients on continuous therapy with warfarin were given omeprazole 20 mg once daily and placebo each for 3 weeks according to a two-centre randomised double-blind cross-over design. 2. Blood samples were obtained once weekly during the run-in and follow-up periods as well as during the first 2 weeks of each treatment period, and twice during the last week of each treatment period. Plasma concentrations of R- and S-warfarin were measured by h.p.l.c. and the anticoagulant effect was assessed using the Trombotest. 3. Twenty-eight patients were evaluated. The mean plasma concentration of R-warfarin was increased by 9.5% during omeprazole treatment compared with placebo, while that of S-warfarin, the more active isomer, was unaffected. The coagulation time was not significantly changed (106 s during omeprazole and 98 s during placebo). Corresponding TT-values (Trombotest) were 8.8 and 9.9 (NS).

Adult↗
PubMed1992

Dynamics of mast cells in the nasal mucosa of patients with allergic rhinitis and non-allergic controls: a biopsy study.

Mast cell degranulation is thought to be an important component of the pathogenesis of allergic rhinitis. Quantitative studies on mast cells in nasal mucosa after allergen exposure have given widely divergent results, ranging from an overall decrease via redistribution to an overall increase. We investigated this problem by employing a combination of anti-IgE and toluidine blue staining of biopsy specimens. In allergic patients anti-IgE was found to identify all mast cells and toluidine blue to detect mast cells that were not (totally) degranulated. The study was composed of two parts done in different patient groups. In the first part of the study biopsies were performed in 23 patients with isolated grass-pollen allergy, once during natural provocation in the summer and once in the winter. Biopsies were also performed in 12 controls. Non-allergic controls were found to have the same number of mast cells in the lamina propria as asymptomatic allergic patients. The controls seldom have mast cells in the epithelium. The patients with isolated grass-pollen allergy showed an increase in the numbers of mast cells in the lamina propria during natural provocation and the same seemed to occur in the epithelium as well. During natural provocation almost all of the mast cells in the epithelium and half of those in the lamina propria were degranulated. In the second part of the study 17 patients with isolated grass-pollen allergy and four controls were challenged daily with allergen extract during a 2-week period in the winter. During this period biopsies were performed at eight different occasions, i.e. once before, six occasions during and once after the provocation period. The results of this part of the study showed that during provocation mast cells migrate to the surface of the nasal mucosa, where they become degranulated, and that the pool of mast cells in the lamina propria was apparently replenished by migration of mast cells from the vessels in the lamina propria. The total number of mast cells in the lamina propria remained approximately the same while the mast cells residing in an increasingly thick layer measured from the basal membrane into the lamina propria became degranulated. After 2 weeks, 82% of the mast cells in the lamina propria was degranulated and it was only in the deepest layers that some toluidine blue positive cells were found.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1992

The nucleotide sequence of a putative membrane transport gene from Clostridium perfringens.

A gene from Clostridium perfringens encoding a highly hydrophobic polypeptide of M(r) = 30,698 was cloned and sequenced. The polypeptide showed similarities with the inner membrane proteins of binding protein-dependent transport systems of the gram negative enterobacteria. The sequence homology to the UgpE and MalG proteins of Escherichia coli was 27.6%, or 60.4 and 52.2%, respectively, taking into account the conservative amino acid changes. The polypeptide contained the EAA---G---------(I/V)-LP motif of the gram negative transport proteins. This motif may thus be very old, as clostridia and E. coli separated some 1.5 x 10(9) years ago. The similarities suggest a common evolutionary origin of these genes.

Amino Acid Sequence↗
PubMed1991

[Hemorrhagic compression of the median nerve after streptokinase treatment].

Hemorrhagic events in patients undergoing fibrinolytic therapy for acute myocardial infarction are well known. We report a case of acute compression of the median nerve caused by a hematoma in the carpal tunnel following infusion of streptokinase in a 71 year-old man with acute myocardial infarction. Operative decompression was carried out. The postoperative course was uneventful, with complete recovery from symptoms of median nerve entrapment.

Aged↗
PubMed1990

Cloning and sequencing of the genes encoding acid-soluble spore proteins from Clostridium perfringens.

In Clostridium perfringens the acid-soluble spore proteins (ASSPs) of the alpha/beta type are encoded by two genes, sspC1 and sspC2. These genes, encoding ASSP C1 and C2 proteins, respectively, were cloned as parts of 3.5-kb genomic fragments. The genes were sequenced and polypeptides of 59 (C1) and 60 (C2) amino acids (aa) were deduced from the nucleotide sequence. The N-terminal Met is removed from the primary translation products in both cases, yielding mature polypeptides with Mrs of 6306 (C1) and 6553 (C2). The aa sequences of the two polypeptides were very similar and showed a closer relationship with C. bifermentans ASSPs than with ASSPs from Bacillus species.

Amino Acid Sequence↗
PubMed1989

Taurine treatment of dyskinesias: an attempt.

Taurine is a sulfonic amino acid with inhibitory effects in the central nervous system. The clinical effect of taurine on dyskinesias was tested in an open trial with 14 patients. Taurine (3 g/day) was given orally in divided doses. Six patients showed an initial improvement which, however, did not persist to the end of the 6-week treatment period. No side effects were observed. It seems unlikely that taurine administration will prove effective in the symptomatic treatment of dyskinesias.

Administration, Oral↗
PubMed1989

Less pain with epidural morphine after knee arthroplasty.

Twenty-two patients were randomly allocated to systemic opioids or epidural morphine the first 10 days after total knee arthroplasty. Pain was recorded daily in a visual analogue scale, and knee motion was measured on Day 10. Pain was lower in the epidural group, with no difference in knee flexion or range of motion.

Analgesia, Epidural↗