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Biomedical subjects

M Saarinen

Publications and source records attributed to M Saarinen.

30 records · Page 2Linked to original sources
PubMed1994

YadA mediates specific binding of enteropathogenic Yersinia enterocolitica to human intestinal submucosa.

The binding of live Yersinia enterocolitica to frozen sections of human intestine was investigated qualitatively by monitoring the binding of bacteria by using Gram or immunoperoxidase staining as well as quantitatively by a new enzyme immunoassay-on-slide method. We have demonstrated that the binding of various Y. enterocolitica serotypes and Escherichia coli clones to frozen sections of human intestine is mediated by the Yersinia adhesin, YadA. The YadA-mediated binding occurs mainly at the submucosal layer of the intestinal wall and only to a limited extent at the mucosal layer; there binding is mostly to the mucin threads. In addition, partially purified YadA binds to frozen sections with a pattern similar to that of intact bacteria. Collagen, laminin, or partially purified YadA only partially inhibited the YadA-mediated binding of bacteria, presumably because YadA is multifunctional. A combination of collagen and laminin inhibited the binding more efficiently. Therefore, YadA may be involved in the interactions with the extracellular matrix molecules after the invasion of the intestinal tissue.

Adhesins, Bacterial↗
PubMed1993

An elongated form of T4 glutaredoxin with four extra residues.

Two different forms of T4 glutaredoxin (thioredoxin) arising from the same gene on a multicopy plasmid in an Escherichia coli expression system have been isolated and characterized. Up to one-fourth of purified T4 glutaredoxin has an extension of four amino acids in the carboxy terminus, with the sequence aspartate, arginine, isoleucine, lysine. This four-residue extension may be caused by a translational +1 frameshift at the UGA terminator codon.

Amino Acid Sequence↗
PubMed1993

Screening of beta-blockers in human serum by ion-pair chromatography and their identification as methyl or acetyl derivatives by gas chromatography-mass spectrometry.

A simultaneous screening method for atenolol, acebutolol, metoprolol, oxprenolol, alprenolol and propranolol by ion-pair chromatography with a column-switching technique was developed. The serum samples were purified using either liquid-liquid extraction or solid-phase extraction methods. The pretreatment of the samples consisted of hydrolysis and protein precipitation. The drug separation was on either octadecylsilica or polymer-based alkyl column material. Binary eluent mixtures containing methanol and a buffer solution with a quaternary ammonium salt as an ion-pair former were used. Detection of the compounds in liquid chromatographic analysis was based on ultraviolet spectra. The effects of methanol, two buffers and the ion-pair former on the retention of the compounds were studied. The determination limits ranged from nanograms to micrograms in the ion-pair chromatographic method, depending on the drug studied. Identification was based on the mass spectra or, if necessary, on selected-ion monitoring spectra of either the methylated or the acetylated compounds obtained by means of gas chromatography-electron impact or negative chemical ionization mass spectrometry. The detection limits for the identified compounds were in the picogram range. The matrix effect was strong, and this resulted in determination limits in the nanogram range with the scan method.

Adrenergic beta-Antagonists↗
PubMed1991

A putative glutathione-binding site in T4 glutaredoxin investigated by site-directed mutagenesis.

A glutathione monomer has been docked into the active site cleft of T4 glutaredoxin (previously called T4 thioredoxin) using molecular graphics. The central part of the cleft is formed by the side chain of Tyr-16 on one side and the residues Thr-64, Met-65, and Pro-66 on the other. The entire glutathione molecule fits well into the cleft. A cis-peptide bond between the residues Met-65 and Pro-66 allows glutathione to bind in an anti-parallel fashion to residues 64-66. Hydrogen bonds can be formed between Met-65 and the glutathione cysteine. This binding positions the glutathione sulfur atom ideally for reaction with the glutaredoxin disulfide. In the model, glutathione can form a hydrogen bond to the hydroxyl group of Tyr-16. Charged interactions at opposite ends of the binding cleft are provided by His-12 and Asp-80. The negatively charged alpha-carboxyl group of glutathione may interact with a positive helix dipole of the protein. Fifteen mutant T4 glutaredoxins have been produced and assayed for glutathione binding by determining thioltransferase activity. Mutant proteins with substitutions in the sides of the cleft (Tyr-16, Pro-66) exhibited the most marked decreases in thioltransferase activity. Mutation of His-12 to a serine decreases the catalytic efficiency whereas substitution of Asp-80 by serine increases the catalytic efficiency. A double mutant, D80S;H12S, has much less affinity for glutathione than either single mutant. Substitution of Cys-14 produces an inactive protein, whereas C17S retains some thioltransferase activity.

Amino Acid Sequence↗
PubMed1988

Malaria prophylaxis with proguanil to Namibian refugee children in Angola.

Following a presumptive treatment with 35 mg chloroquine base/kg, 484 Namibian children between 5 months and 5 years of age received 50 mg of proguanil daily for 4 months. They were compared with 268 children living in a very adjacent area who received vitamin tablets after the initial chloroquine medication. Fewer fever episodes were recorded among the children who received proguanil and they were also requiring less presumptive treatments with chloroquine during the period of study, but there were only minor differences in parasite rate between the two groups at the end of the study period. Despite the reduction of morbidity, the required efforts were too large to justify another period of drug prophylaxis.

Angola↗
PubMed1986

C-reactive protein compared with white blood cell count and erythrocyte sedimentation rate in the diagnosis of acute appendicitis in children.

Acute abdominal symptoms in 162 children were investigated with rapidly quantified C-reactive protein (CRP), white blood cell (WBC) count and erythrocyte sedimentation rate (ESR) as laboratory parameters. When the symptoms had been present for at least 12 hours, the CRP level was greater than 10 mg/l in 72% of cases with histologic evidence of appendicitis, while leukocytosis (WBC greater than 15 000/mm3) and raised ESR (greater than 20 mm/l h) were found in 58% and 51%, respectively. If appendicitis had progressed to gangrenous stage, however, CRP alone was capable of identifying 83% of cases, while 76% had leukocytosis and 60% elevated ESR. When perforation had occurred there was greatly increased CRP and invariably leukocytosis, but elevated ESR in only 60%. With the combination CRP and WBC count (using rise in one or both), 88% of all appendicitis cases could be identified, and at least 96% of those with gangrene or perforation. The predictive value of combined positive CRP and WBC tests was not less than 93%.

Acute Disease↗
PubMed1985

Acute appendicitis not associated with social class among children.

Acute appendicitis has previously been found to be associated with social class. In an attempt to confirm this, 125 patients with histologically verified acute appendicitis were compared with 1802 control children, randomly selected from the schools of the City of Helsinki. Social class determination was based on father's occupation in families with two parents, and on mother's occupation in single provider families. No association with social class was found. The proportion of single provider families was around 25% among both cases and controls. Appendicitis patients are one potential source of control groups in epidemiological studies.

Acute Disease↗
PubMed1980

The normal human magnetocardiogram. II. A multipole analysis.

This paper presents a multipole analysis of the QRS complex of the normal magnetocardiogram (MCG) of six normal subjects. The multipole strengths up to the octupole term were determined from the measured distribution of the z-component of the cardiac magnetic field (the component perpendicular to the frontal plane). This equivalent magnetic multipole generator was found to represent the cardiac magnetic field with a minimum error of less than 10%. The dipolar term of the expansion was found to represent the field distribution with reasonable accuracy early during ventricular activation, whereas late during activation, the higher multipole terms were clearly more significant.

Cardiology↗
PubMed1978

The normal magnetocardiogram: I Morphology.

This paper presents a morphological study of the real-time magnetocardiogram (MCG) of normal subjects. The MCGs were obtained using a gradiometric measurement technique, and the magnetic field component perpendicular to the frontal plane (z-compenent) was studied. Forty-one healthy men and women were mapped from 51 positions on the chest, and the statistics of the waveforms of the MCG were computed. In 21 of the subjects both the MCG and the ECG were analyzed. The general behaviour of the MCGs is discussed and proposals for the standardization of the measurements are made.

Adult↗