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Biomedical subjects

P Groff

Publications and source records attributed to P Groff.

At least 19 recordsLinked to original sources
PubMed2000

Hb Ernz [beta123(H1)Thr-->Asn] and Hb Renert [beta133(H11)Val-->Ala]: two new neutral variants revealed by reversed phase high performance liquid chromatography analysis.

Analysis of globin chains by reversed phase high performance liquid chromatography, used as an additional tool for characterizing hemoglobin variants, has led to the discovery of a new class of variants that display only differences in hydrophobicity. Two such variants are here described. Hb Ernz was found in a man of Italian origin who was polycythemic, and in two of his three daughters who were hematologically normal. Hb Renert, a slightly unstable variant, was found in a man from Cape Verde who also carried Hb S and presented with chronic hemolysis. The structural abnormalities were characterized by protein structure methods involving reversed phase high performance liquid chromatographic separations of globins and peptides, followed by mass spectrometry studies (electrospray, ion trap, tandem mass spectrometry).

Chromatography, High Pressure Liquid↗
PubMed1998

Incidence of insulin dependent diabetes mellitus in children 0-14 years old in the Veneto Region, Italy.

The objective of this study was to provide reliable data on the incidence of type 1 diabetes, in children aged 0-14 years, in the Veneto region, and to better understand its geographical variability throughout Italy and Europe. All new cases of type 1 diabetes diagnosed between 1st January 1993 and 31st December 1994 among residents in Veneto were recorded. Clinical records from 33 hospitals in the region were used as the primary source for this study. The number of disease-related free-of-charge prescriptions served as a secondary source. The completeness of ascertainment was estimated at 89%. The mean incidence estimated over the 1993-1994 period was 10.7 per 100,000/year. The Veneto region appears to have a relatively high incidence of IDDM among non-insular Italian regions. No significant sex-related difference in incidence was noted; the male/female ratio was 1.5.

Adolescent↗
PubMed1997

Combined mass spectrometric methods for the characterization of human hemoglobin variants localized within alpha T9 peptide: identification of Hb Villeurbanne alpha 89 (FG1) His-->Tyr.

Mutation-induced amino acid exchanges occurring on the large T9 peptide of the alpha-chain of human hemoglobin (residues 62-90) are difficult to identify. Despite their high m/z value (around m/z 3000), collision-induced dissociation spectra of liquid secondary ion mass spectrometrically generated protonated alpha T9 peptides were performed successfully. In parallel electrospray mass spectrometry (MS) was used both to measure the molecular mass of the intact proteins and to determine the number of protonatable sites in the alpha T9 peptides. Peptide ladder sequencing using carboxypeptidase digestions and analysis of the truncated peptides by matrix-assisted laser desorption ionization time-of-flight MS confirmed the interpretation. This set of methods allowed the characterization of three hemoglobin variants, with amino acid exchanges located in the alpha T9 part of the sequence. Two of them, Hb Aztec [alpha 76(EF5) Met-->Thr] and Hb M-Iwate [alpha 87(F8) His-->Tyr] were already known. The third [alpha 89(FG1) His-->Tyr] was novel and named Hb Villeurbanne.

Amino Acid Sequence↗
PubMed1997

Quantitative liver parameters of HCV infection: relation to HCV genotypes, viremia and response to interferon treatment.

BACKGROUND/AIMS: This study aimed to evaluate the relation between the number of hepatocytes positive for HCV antigens and the amount of HCV RNA in the liver and to evaluate the relationship between the above parameters and viremia levels, HCV genotype and response to interferon treatment. METHODS: This was a retrospective study on 31 consecutive patients with chronic HCV-related liver disease, selected on the basis of the availability of frozen liver tissue for both liver HCV antigens detection and liver HCV RNA quantitation. HCV antigens (immunohistochemistry), liver and plasma HCV RNA (competitive RT-PCR), and HCV genotype (commercial kit) were studied. RESULTS: A significant correlation (p=0.0005) was found between the amount of liver HCV RNA (log 10 copy/microg of extracted RNA) and the number of HCV-infected hepatocytes (scored from 0 to 3). These parameters were not significantly correlated with viremia levels. The highest liver HCV RNA levels and HCV antigen scores were found in patients infected with genotype 1b. Liver HCV RNA (median 541 x 10(3) vs 118 x 10(3) copy number/microg, p=0.031) and liver HCV antigens (mean score 2.3 vs 1.3, p=0.018) but not plasma HCV RNA (median 14956 x 10(3) vs 2885 [correction of 2.885] x 10(3) copy number/ml, ns) were significantly higher in patients not responding to interferon treatment compared to responders. CONCLUSIONS: The tissue parameters tested in this study were significantly correlated, shared the same clinical implications and predicted short-term response to interferon treatment better than viremia levels. We suggest that these tests should be included in the study protocol of patients under evaluation for interferon treatment, basing the choice on local facilities.

Adult↗
PubMed1997

Bridging student health risks and academic achievement through comprehensive school health programs.

In the National Action Plan for Comprehensive School Health Education, representatives for over 40 health, education, and social service organizations viewed education and health as independent systems. Participation concluded that healthy children learn better, and they cautioned that no curriculum can compensate for deficiencies in student health status. While literature confirms the complexity of health issues confronting today's students, schools face enormous pressure to improve academic skills. Local school leaders and stakeholders often remain unconvinced that improving student health represents a means to achieving improved academic outcomes. A rich body of literature confirms a direct link between student health risk behavior and education outcomes, education behavior, and student attitudes about education. This article summarizes relevant information concerning the health risk behavioral categories of intentional injuries; tobacco; alcohol, and other drugs; dietary, physical activity, and sexual risk behaviors.

Adolescent↗
PubMed1995

Specific reactivity of fluorescein isothiocyanate-conjugated separated IgG and IgA from celiac disease sera on human tissues.

Study of the reaction of celiac disease-related antibodies with human substrates has been hampered by the immunological cross-reactivity between fluorescein isothiocyanate-conjugated anti-human immunoglobulins and immunoglobulins normally present in human tissues. In order to overcome this problem we extracted IgG from 2 celiac disease sera (positive for specific IgG and IgA antibodies) using a genetically engineered recombinant form of streptococcal protein G covalently immobilized on 4% agarose beads. The separated IgG and IgA was conjugated with fluorescein isothiocyanate and used in direct immunofluorescence on 0 blood group human duodenum, liver, and myocardium. Staining of the lamina propria beneath the villous epithelium, the endomysium of smooth muscle layers in the duodenum, and the liver sinusoidal and pericellular myocardial matrix was observed. The reactivity of celiac disease-related antibodies with various human tissues indicates that these antibodies are the result of a systemic immune response directed against all tissues containing matrix proteins.

Animals↗
PubMed1995

Hepatitis C virus (HCV) genotype, tissue HCV antigens, hepatocellular expression of HLA-A,B,C, and intercellular adhesion-1 molecules. Clues to pathogenesis of hepatocellular damage and response to interferon treatment in patients with chronic hepatitis C.

To obtain information on the mechanisms of hepatocellular damage and the determinants of response to interferon, hepatitis C virus (HCV) genotype, tissue HCV antigens, hepatocellular expression of HLA-A,B,C and intercellular adhesion-1 molecules, and the number of lobular T lymphocytes were studied in 38 anti-HCV-positive patients. 14 patients did not show a primary response to interferon treatment. HCV genotype 1b was detected in 11 of them. They displayed higher scores of HCV-positive hepatocytes, HLA-A,B,C, and ICAM-1 molecules expression than with the responders. HCV-infected hepatocytes maintained the capacity to express HLA-A,B,C and ICAM-1 molecules. CD8-positive T cells in contact with infected hepatocytes and Councilman-like bodies were observed. A significant correlation was found between the number of lobular CD8-positive T cells and alanine amino transferase levels. No differences were observed in clinical, biochemical, and histological features between patients with high and low number of hepatocytes containing HCV antigens. These data suggest a prominent role of T cell-mediated cytotoxicity in the genesis of hepatocellular damage. The high expression of interferon-inducible antigens like HLA-A,B,C molecules suggests the presence of strong activation of the interferon system possibly related to high HCV replication in nonresponder patients infected with genotype 1b.

Antigens, Viral↗
PubMed1995

Hepatocellular codistribution of c100, c33, c22, and NS5 hepatitis C virus antigens detected by using immunopurified polyclonal spontaneous human antibodies.

Hepatitis C virus (HCV) antigens in liver biopsy have been detected by immunohistochemistry using both spontaneous human IgG and murine monoclonal or rabbit polyclonal monospecific reagents. Conflicting results have been obtained in different studies. This was probably because of the incapacity of single experimental antibodies, raised against synthetic or recombinant peptides, to recognize native tissue antigens. To overcome this possibility, we immunopurified monospecific spontaneous polyclonal human Ig, therefore induced by native antigens, from the single antigen-containing bands of RIBA 3 strips. Antibodies to c100, c33, c22, and NS5 antigens were obtained from the serum of a patient affected by chronic hepatitis C. The IgG fraction of this serum had proved to stain tissue HCV antigens. Eight biopsies were selected on the basis of strong hepatocellular reactivity with the whole IgG fraction in a variable number (from 5% to 75%) of cells. The four antigens were detected in all biopsies; a clear cellular codistribution was observed on serial sections. These data demonstrate that the possibility to identify HCV antigens in liver biopsies is higher when using human antibodies induced by native antigens rather than experimental antibodies. The approach of immunopurification of human antibodies can be extended to other HCV-related epitopes to obtain reagents useful for the selection and optimization of monoclonal or polyclonal antibodies.

Antigens, Viral↗
PubMed1995

Structural determination of a new electrophoreticaly silent variant: hemoglobin Alzette, beta 104(G6)Arg --> Lys.

A new electrophoreticaly neutral hemoglobin variant was found by ion-exchange high-performance liquid chromatography (HPLC). The molecular mass of the beta-chain was shifted down 28 mass units. The modification was found in the beta T-11 peptide that co-elutes with beta T-14 in the tryptic HPLC profile. Collision-induced decomposition of the protonated modified peptide indicated the Arg --> Lys exchange at the C-terminus. This modifies the fragmentation pattern as charge-remote processes induced by the strong basicity of arginine were replaced by charge-induced mechanisms. The exchanged 104Arg is one of the chloride binding sites in the central cavity of Hb.

Amino Acid Sequence↗
PubMed1994

Increased risk of hepatocellular carcinoma development in patients with cirrhosis and with high hepatocellular proliferation.

The immunohistochemical determination of the accessory protein of DNA-polymerase delta (PCNA), a marker of an early S-phase of the cell cycle, was used to evaluate cell proliferation retrospectively in formalin-fixed, paraffin-embedded liver biopsy sections in a group of patients with cirrhosis of similar age and duration of follow up, and with no evidence of hepatocellular carcinoma (41), including 17 patients with and 24 without hepatocellular carcinoma appearance during follow up. Proliferation was expressed as total (PCNA-TOT) and strongly (PCNA-STRO) positive nuclei per 1000 hepatocytes. The presence of dysplasia was also recorded. Histological findings and biochemical data, at the time of liver biopsy, were compared in the two groups. While total PCNA positivities were not significantly different in the two groups, strong reactivity was significantly higher in patients who eventually developed hepato-cellular carcinoma (median 0.7 vs 2.6). Univariate analysis of histological and biochemical data at the time of biopsy, followed by a stepwise regression study, showed that the significant parameters for a time-dependent disease-free state were, in decreasing order: cholesterol, PCNA-STRO, PCNA-TOT and alpha foeto-protein. Other clinical, biochemical and histological parameters, including dysplasia, provided no further information. From these data, hepatocellular proliferation can be evaluated in patients with cirrhosis with a currently available technique. Patients with high cell proliferation are at increased risk of developing hepatocellular carcinoma and may require differentiated follow up.

Adult↗
PubMed1994

Hepatocellular expression of HLA-A, B, C molecules predicts primary response to interferon in patients with chronic hepatitis C.

Primary response rate to alpha-interferon (IFN) is about 50% in patients with chronic hepatitis C. Criteria for predicting a positive primary response are lacking. HLA-A,B,C molecule expression is known to be stimulated by viral infections. In 36 consecutive interferon-treated anti-HCV positive patients with an available frozen liver biopsy sample, the predictive value of liver HLA-A,B,C expression, and of histologic, clinical, and biochemical parameters was evaluated. Response to treatment was defined by normalization of transaminases, and disappearance of serum HCV-RNA within 3 months. According to these criteria, 17 patients were classified as nonresponders and 19 were classified as responders. The pattern of HLA-A,B,C hepatocellular positivity varied from normal (negative or occasional faint staining of hepatocellular membranes) to diffuse, strong "honeycomb" positivity. The highest scores of positivity were found in nonresponder patients. The discriminant capacity of HLA-A,B,C scores of positivity was compared with clinical, biochemical and histologic parameters by discriminant analysis. HLA-A,B,C expression was found to be the main discriminant parameter, in addition to alkaline phosphate (ALP) and gamma-glutamyl-transpeptidase (GGT) which added little additional information. The higher hepatocellular expression of class I MHC molecules in nonresponder cases may reflect a different viral effect on hepatocytes, which is induced by different HCV genotypes or levels of viremia. From a clinical point of view, the pretreatment HLA-A,B,C pattern of positivity represents a powerful tool in the selection of patients for interferon treatment.

Adult↗
PubMed1994

Ito cell heterogeneity: desmin-negative Ito cells in normal rat liver.

The presence of desmin is used to identify Ito cells in rat liver and to evaluate the purity of separated and cultured Ito cells. Heterogeneity of the normal Ito cell population has been suggested; this could include variations in the content of cytoskeletal components. For these reasons we decided to reevaluate the use of desmin staining as a phenotypical marker of Ito cells in normal rat liver. Our approach was to combine desmin staining with identification of vitamin A (autofluorescence), lipid droplets (Sudan III), vimentin, laminin and tenascin, using cryostat sections: Immunofluorescence, double-immunofluorescence or immunoperoxidase techniques were used. All the techniques described corroborate the existence of desmin-negative Ito cells, mainly located in pericentral areas. In fact, lobular desmin-positive cells showed uneven distribution because they were more frequent in periportal than in pericentral areas. On the contrary, Ito cells identified on the basis of morphological criteria or positivity for laminin were evenly distributed. Double immunofluorescence confirmed this observation, showing nearly complete codistribution of laminin and desmin in periportal areas. Outside this area, positivity for desmin was observed only in about 50% of laminin-positive cells. Our observations suggest that desmin cannot be viewed as a phenotypical marker but rather is a differentiation marker of Ito cells, possibly indicating a specific functional state.

Animals↗
PubMed1993

Hb Melusine [alpha 114(GH2)Pro-->Ser]: a new neutral hemoglobin variant.

Hb Melusine [alpha 114(GH2)Pro-->Ser] was found in an Algerian patient during a systematic screening for hemoglobinopathies performed in Luxembourg. The abnormal hemoglobin was suspected when a thickening of the Hb A band was observed by isoelectrofocusing. The mutant hemoglobin was silent in all other electrophoretic methods used for presumptive diagnosis with the exception of globin electrophoresis in the presence of Triton X-100. This technique revealed an alpha chain considerably more hydrophobic than normal. The structural abnormality of Hb Melusine concerns position alpha 114(GH2) that belongs to a cluster of hydrophobic residues localized in the N-terminal half of the alpha T-12b tryptic peptide. It has been shown in the case of another variant of that position (Hb Nouakchott), that the replacement of the Pro GH2 by a Leu was responsible for a dramatic increase in the retention time of the alpha polypeptide chain during reversed phase high performance liquid chromatography, much higher than that reported for similar substitutions in other regions of the hemoglobin molecule.

Adult↗
PubMed1991

Cleavage by protease from Staphylococcus aureus V8: an improvement in the sequence analysis of human hemoglobin variants.

Protease from Staphylococcus aureus V8 cleaves either at glutamic residues or at both aspartic and glutamic residues, depending on the experimental conditions. In structural analyses of human hemoglobin variants, the specificity of this enzyme is of considerable interest to localize substitutions occurring in medium or large size peptides as it cleaves in smaller fragments which may be unambiguously characterized. It may also recognize the replacement of an acidic residue by the corresponding amide, or vice versa, avoiding protein sequence analysis. The various aspects of the use of protease V8 are illustrated by the study of four alpha chain hemoglobin variants concerning peptides alpha T-9 and alpha T-12b.

Amino Acid Sequence↗
PubMed1991

Handedness effects in the detection of dichotically-presented words and emotions.

Left-handed and right-handed subjects were given two dichotic listening tasks using identical material. In one task, they were asked to determine whether or not a specific target word was present (verbal task). In the other task, subjects were asked to indicate whether or not one of the dichotically-competing words was spoken in a particular affective tone (emotion task). Overall, a right-ear advantage (REA) was found with the verbal task and a left-ear advantage (LEA) with the emotion task. Left-handers showed a slightly smaller REA than right-handers on the verbal task, but a slightly larger LEA on the emotion task. This finding suggests that left- and right-hemispheric functions are not related in a complementary fashion and that handedness effects for nonverbal tasks are different from those seen with verbal tasks. The emotional LEA was much larger for angry stimuli than for happy, sad, or neutral stimuli. Rather than providing evidence for a hemisphere by affective valence interaction, such results suggest a stimulus-specific effect.

Adult↗
PubMed1989

Hb Luxembourg [alpha 24(B5) Tyr----His]: a new unstable variant.

Hb Luxembourg [alpha 24(B5)Tyr----His] was found in association with mild hemolytic anemia and increased indirect bilirubinemia in a family originating from the Netherlands. The slight instability of this variant may be the consequence of an indirect effect of the substitution on the alpha 1 beta 1 contact since position alpha 24 (B5) is internal and in contact with several residues involved in this interface.

Adolescent↗