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S Ranta

Publications and source records attributed to S Ranta.

At least 37 records · Page 2Linked to original sources
PubMed1995

Cornea plana congenita gene assigned to the long arm of chromosome 12 by linkage analysis.

We report the mapping of the locus for autosomal recessive cornea plana congenita (CNA2; MIM 217300) by linkage analysis to the approximately 10-cM interval between markers D12S82 and D12S327. The recessively inherited disorder studied here is more severe than dominant forms. Its main manifestations are reduced curvature and hazy limbus of the cornea, opacities in the corneal stroma, and marked corneal arcus at early age. Our results provide a starting point for the positional cloning of CNA2 and the elucidation of the pathogenesis of the disease.

Adult↗
PubMed1995

Muscle-eye-brain disease and Fukuyama type congenital muscular dystrophy are not allelic.

Muscle-Eye-Brain disease (MEB) and Fukuyama type congenital muscular dystrophy (FCMD) are clinically similar autosomal recessive diseases, characterized by congenital muscular dystrophy and severe mental retardation, raising the possibility that they might be caused by mutations of the same gene. Recently FCMD was localized to chromosome 9q31-33 by linkage. We performed a linkage study in seven Finnish MEB families with 12 affected patients using markers D9S53, D9S58, D9S59 and HXB. The MEB phenotype was not linked to any of the markers. A multipoint linkage analysis excluded the entire region harboring FCMD. We thus conclude that MEB and FCMD are not allelic.

Adolescent↗
PubMed1994

The gene for a recessively inherited human childhood progressive epilepsy with mental retardation maps to the distal short arm of chromosome 8.

A recently delineated childhood epilepsy has hitherto been observed only in a small geographic region in northern Finland, where, with the exception of one, both parents of all of the 11 sibships with affected individuals descend from one or two founding couples. The disease is characterized by generalized tonic-clonic seizures with onset at 5-10 years and progressive, severe mental retardation with onset 2-5 years after the first seizures. In this study the gene locus is assigned to the telomeric region of chromosome 8p by linkage. Analyses of recombinations place the locus in the 7-centimorgan interval between AFM185xb2 and D8S262 in which three markers, D8S504, D8S264, and AFM077yg5, show no recombinations with the phenotype. Haplotypes comprising alleles at the above five loci support the hypothesis of a single founding mutation for all affected chromosomes except the one belonging to the unrelated parent, who has a very different haplotype, suggesting another mutation or a very old ancestry of a single mutation. This study raises to three the number of heritable epilepsies whose gene loci have been mapped and provides a starting point for the cloning of the gene. It also suggests the possibility that the disease might not be limited to the northern Finnish population.

Adult↗
PubMed1994

Cohen syndrome gene assigned to the long arm of chromosome 8 by linkage analysis.

Cohen syndrome is an autosomal recessive disorder characterized by mental and motor retardation, short stature, microcephaly, several dysmorphic features, major ocular symptoms and granulocytopenia. Major research challenges are the confusing nosology and the pleiotropy of the gene. We report the mapping of a locus (CHS1) by linkage analysis in as few as four two-generation pedigrees with uniform clinical features. CHS1 was assigned to an interval of approximately 10 cM between D8S270 and D8S521. Our results provide a tool to a more accurate definition of Cohen syndrome(s) and a starting point for the positional cloning of CHS1.

Abnormalities, Multiple↗
PubMed1993

Protection by nitecapone against sodium taurocholate-induced damage to cultured gastric cells.

The goal of this study was to observe if nitecapone protected against taurocholate-induced damage in primary cultured rat gastric mucosal cells, as well as in a well-differentiated human gastric epithelial cell line (MKN 28). Prostaglandins were measured to analyze the protection mechanism. In primary rat gastric mucosal cell culture, nitecapone 125-250 microM protected the cells significantly against damage induced by sodium taurocholate, increasing cell viability by 31-38%. In the human gastric epithelial cell line, in which mitochondrial activity was measured as an indication of cell viability, nitecapone (62.5-250 microM) protected the cells against sodium taurocholate-induced damage by 12-20%. Prostaglandin E2, thromboxane B2, and 6-keto-prostaglandin F1 alpha measurements in the primary cultured rat gastric mucosal cells showed that nitecapone (125 microM and 250 microM) significantly stimulated prostaglandin E2 production (84.7% and 61.0%, respectively), and inhibited thromboxane B2 formation (50% at 250 microM), while the 6-keto-prostaglandin F1 alpha formation was unaffected. Nitecapone had no effect on prostaglandin E2 production in the MKN 28 epithelial cell line. Indomethacin or aspirin, at concentrations that did not affect cell viability, antagonized the stimulative effect of nitecapone on prostaglandin E2 formation in the primary cultured rat gastric mucosal cells. Although the prostaglandin E2 synthesis was blocked, nitecapone still protected against cell damage induced by taurocholate. These results demonstrated the direct and efficacious protection of nitecapone on gastric cell level and suggest that the "cytoprotection" by nitecapone against taurocholate may not be mediated through the mechanism of stimulated synthesis of prostaglandin E2.

Analysis of Variance↗
PubMed1992

Weight loss normalizes the inhibitory effect of N6-(phenylisopropyl)adenosine on lipolysis in fat cells of massively obese human subjects.

1. Fat cells were isolated from massively obese patients at or before gastric bypass, from other patients after normalization of body weight after gastric bypass or gastroplasty (post-bypass patients) and from control subjects of a stable normal body weight. 2. The inhibition of isoprenaline-stimulated lipolysis by N6-(phenylisopropyl)adenosine in the presence of adenosine deaminase was much attenuated in cells from the massively obese patients as compared with those from normal-weight control subjects, but was normal in cells from post-bypass patients. 3. Isolated fat cells of the massively obese patients were larger (913 +/- 197 pl, mean +/- SEM) than those of the normal-weight group (437 +/- 95 pl). The volume of cells from the post-bypass patients was only 125 +/- 49 pl, although the body mass index of this group was almost exactly the same as that of the normal-weight control subjects. 4. Although epidemiological studies have suggested that genetic factors are important in the development and maintenance of obesity, these results demonstrate that the changes observed in the inhibitory regulation of lipolysis in obesity are secondary.

Adenosine Deaminase↗
PubMed1991

Attenuated adenosine-sensitivity and decreased adenosine-receptor number in adipocyte plasma membranes in human obesity.

Fat-cells were isolated from patients of body-mass indices (BMIs) ranging from 17.9 to 83.9 kg/m2. Isoprenaline-stimulated cyclic AMP accumulation in cells prepared from obese subjects as compared with normal-weight subjects, was less sensitive to inhibition by the adenosine agonist N6-(phenylisopropyl)adenosine (PIA) (P = 0.047). The inhibition of 7 beta-desacetyl-7 beta-[gamma-(N-methylpiperazino) butyryl]-forskolin-stimulated adenylate cyclase by PIA in the presence of adenosine deaminase was also much attenuated in crude plasma membranes of adipocytes prepared from massively obese patients as compared with lean controls (P = 0.0143). This difference was probably not due to different cell size, because adenylate cyclase of crude plasma membranes of large adipocytes was actually more sensitive to PIA than was adenylate cyclase of membranes of smaller fat-cells co-isolated from the same individual. The stimulatory effect of PIA on glucose uptake in the presence of adenosine deaminase was depressed in adipocytes prepared from obese subjects and correlated with BMI at r = -0.626 (P = 0.007) at 100 nM-PIA. The adenosine receptors were studied by using the adenosine antagonist 1,3-[3H]dipropyl-8-cyclopentylxanthine. The binding was rapid and proportional to protein concentration. There was no difference in the affinities of receptors in membranes of obese and normal-weight subjects; Kd values of all patients averaged 3.3 nM. Bmax values were 54 and 130 fmol/mg of protein in membranes prepared from seven obese and five control patients respectively. The Bmax values calculated per mg of protein correlated with BMI at r = -0.539 (P = 0.047). The adenosine content of adipose tissue was higher in obese than in control subjects. These results demonstrate an attenuated response of cyclic AMP accumulation, adenylate cyclase and glucose uptake to adenosine in fat-cells prepared from obese subjects, and suggest that this change is at least partly due to changes in the amount of adenosine receptors, but not their affinity. The decreased receptor number could be due to higher adenosine content. A higher adenosine concentration in adipose tissue could explain why lipolysis is inhibited in situ in obesity, and the desensitization could explain the diminished response to adenosine analogues in isolated fat-cells.

Adenosine↗
PubMed1991

Different metabolic regulation by adenosine in omental and subcutaneous adipose tissue.

Adenosine content was higher in omental adipose tissue (0.91 +/- 0.13 nmol g-1 of wet weight; mean +/- S.E.M.) than in abdominal subcutaneous adipose tissue (0.42 +/- 0.08 nmol g-1 of wet weight) in rapidly frozen surgical biopsy samples taken from ten patients undergoing elective abdominal surgery. This difference was statistically significant (P less than 0.002). The sensitivity of isoprenaline-stimulated lipolysis to inhibition by N6-(phenylisopropyl)adenosine was studied in omental and abdominal subcutaneous adipocytes isolated from nine patients. The effect of this adenosine Ri-site agonist was less pronounced in omental than in abdominal subcutaneous adipocytes which could be due to a desensitization phenomenon. This difference was statistically significant (P = 0.012). The ratio of the inhibitory guanine nucleotide binding proteins Gi1 and Gi2 to the corresponding stimulatory protein Gs was the same in plasma membranes prepared from omental and abdominal subcutaneous adipocytes. In conclusion, in omental adipose tissue, adenosine content is higher and the response to this nucleoside is less pronounced than in subcutaneous adipocytes. This difference cannot be explained by a different (Gi1 + Gi2)/Gs ratio.

Abdomen↗
PubMed1989

Adipocyte plasma-membrane Gi and Gs in insulinopenic diabetic patients.

Changes in the amounts and functions of G-proteins have been reported in diabetic rats. We determined the Gi/Gs ratio of adipocyte plasma membranes in six insulinopenic diabetic patients and matched controls by immunoblotting with antisera against synthetic peptides corresponding to regions of G-proteins. No consistent changes in the Gi/Gs ratio were observed. It is still possible that the functional status of the G-proteins may be altered in diabetes.

Adipose Tissue↗
PubMed1986

Attenuated adenosine R-site effect in adipocytes in obesity.

Adenosine is a local hormone or a retaliatory metabolite that executes its effect via a plasma membrane receptor, the R-site. In human adipocytes it inhibits cyclic AMP accumulation and lipolysis. N6-(phenylisopropyl)adenosine is a nonmetabolizable derivative that is an R-site agonist not sharing other effects of the parent nucleoside. In subcutaneous abdominal fat cells from obese subjects (130% to 207% of ideal body weight, N = 8), the antilipolytic effect of N6-(phenylisopropyl) adenosine was markedly attenuated as compared to that in fat cells from normal weight subjects (83% to 121% of ideal body weight, N = 8). There was a negative correlation between the effectiveness of the nucleoside analog and the relative body weight of the donor. The effect of N6-(phenylisopropyl)adenosine on cyclic AMP accumulation was similarly attenuated. These findings may explain some of the metabolic alterations observed in obesity.

Adenosine↗
PubMed1985

Proportions of Ig classes and subclasses in rubella antibodies.

The proportions of six immunoglobulin isotypes (IgA, IgM, IgG1, IgG2, IgG3, and IgG4) in rubella antibody responses were quantified in 40 serum samples (20 patients). The first sample from each patient was taken during the first days of the illness, and the second sample 10 +/- 1 days later. A tenfold average increase in antibody concentration was observed between the first and the second sample. IgM was the predominant isotype in the first sample (average, 73% of all antibodies), followed by IgG1 (19%). IgA and IgG3 antibodies were detected in only a few of the first samples, and IgG2 or IgG4 in none. In the second samples IgG1 was the predominant antibody isotype (average, 59%). Next came IgM (23%), followed by IgA (8%) and IgG3 (3%). No IgG2 or IgG4 antibodies were detected. Although the proportion of IgM antibodies was lower in the second than in the first samples, their concentration increased in all patients (the average factor was 7). The kinetics of the IgA response was irregular. In some patients there was a strong (up to 90-fold) increase in IgA antibodies, but in two patients a small drop was detected. The kappa- to lambda-chain ratio of rubella antibodies appears to be close to the expected 2:1. It decreased in some patients during the 10 days and increased in others.

Antibodies, Viral↗
PubMed1985

Assay of adenosine in human adipose tissue.

A method is described to assay the adenosine content of human adipose tissue. Tissue pieces of 10-20 mg were frozen within 1 sec of excision by a conchotome. The pieces were pooled and ground in liquid nitrogen, divided into samples weighing 50-100 mg each and placed in perchloric acid. Neutralized defatted extracts were treated by Dowex AG-1 to remove nucleotides and lyophilized. The adenosine content was measured by RIA using antiserum raised against laevulinic acid (0(2'),3'-adenosine-acetal)-albumin conjugate. The adenosine content in human abdominal sc adipose tissue was 0.56 +/- 0.08 nmol/g of tissue (mean +/- SEM). This shows that adenosine is present in human adipose tissue at concentrations that have been shown to have regulatory effects on cAMP accumulation and lipolysis.

Adenosine↗
PubMed1984

Inhibition of adenosine 3',5'-monophosphate accumulation and lipolysis by adenosine analogs in human subcutaneous adipocytes.

Lipolysis and cAMP accumulation were inhibited by low concentrations of adenosine and its analogs in human sc adipocytes stimulated by 2 microM DL-isoproterenol. The order of potency of the adenosine analogs tested was N6-(phenylisopropyl)adenosine greater than 2-chloroadenosine greater than 5'-N-ethylcarboxamidoadenosine greater than adenosine greater than 2',5'-dideoxyadenosine greater than 2'-deoxyadenosine. Inosine was without effect. No stimulation of cAMP accumulation by 5'-N-ethylcarboxamidoadenosine was observed. These results strongly suggest the presence of inhibitory adenosine Ri- and P-sites and the absence of stimulatory Ra-sites in human sc adipocytes.

Adenosine↗
PubMed1983

Relative immunogenicity in mice of different regions of the human IgG.

Monoclonal mouse antibodies to human IgG myeloma proteins were produced and characterized by determining their binding to a series of different purified myeloma proteins. Two types of immunization schedules were used. When the same myeloma protein was used for priming and boosting the mouse, all determinants of the molecule were effectively immunogenic. Of the 353 clones originating from these experiments 42% secreted anti-Fv antibodies, 57% anti-CH antibodies, and 0.85% anti-CL antibodies. In another schedule only the CL and CH regions were the same in priming and boosting; 270 anti-CH (94%), 18 anti-CL (16%), and no anti-FV hybridomas were found. Our results indicate that a unit mass of the FV region was 1.3 times more antigenic than a unit mass of the CH region. A unit mass of the CH region was nearly five times more antigenic than a unit mass of the CL domain when the antigenicity of the FV region had been excluded. When the antigenicity of the FV region had not been excluded, a unit mass of the CH region was about twenty times more antigenic than a unit mass of the CL domain. The data suggest that an antigenic competition was taking place between different parts of the molecule and that the strongly antigenic region (FV) was more efficient in competing out the nearest neighbour (CL) than in competing out other parts of the molecule.

Animals↗