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Biomedical subjects

M C Belvedere

Publications and source records attributed to M C Belvedere.

9 recordsLinked to original sources
PubMed1993

Visual guidance in infants' reaching toward suddenly displaced targets.

This experiment evaluated the role of visual input about the location of a target object and the location of the hand in reaching by infants and adults. 5- and 9-month-old infants were presented with illuminated toys to reach for in a dark room. On no-switch trials, the toy remained illuminated throughout the infant's reach, whereas on switch trials the first-lit toy was replaced during the reach by a second-lit toy at a different position. On approximately half of the trials of each type a luminescent marker was attached to the reaching hand. Adult subjects (tested without the hand marker) fully compensated to the second-lit toy on switch trials, during a second reaching segment. On switch trials, 9-month-olds partially adjusted to the second-lit toy when wearing the hand marker and did not adjust without it. On no-switch trials, 9-month-olds reached just as accurately with or without the hand marker. 5-month-olds were generally inaccurate in their reaching and were unaffected by the presence or absence of the hand marker. The findings suggest that during the development of reaching there is an increase in visual guidance during the approach phase of reaches.

Adult↗
PubMed1988

Italian extended HLA haplotypes in congenital adrenal hyperplasia.

In order to complete the data on human 21-Hydroxylase deficiency, we present a study on HLA markers in 35 Italian families (14 from Northern, eight from Central and 13 from Southern Italy) with one affected child. Three children from the issue of first cousin marriages were homozygous for the whole HLA haplotype. Extended haplotypes shared by unrelated patients were not found, and a total absence of the HLA Bw47 allele among the haplotypes carrying the disease as well as normal haplotypes was observed. The absence of A1 Cw7 B8 BfS C4AQ0 C4B1 DR3 extended haplotype was instead confirmed. Allele frequencies in the different clinical forms were analyzed: BfSO7 allele frequency was significantly increased on haplotypes of the salt-wasting form (p less than 0.01). We noticed two duplications (C4B1-2) of C4B genes, on haplotypes involved in the disease. Allele distribution in the regions studied showed that Bw22 (w55), Cw3 and DR2 were characteristic of Northern patients, while B15 was found in patients from Central Italy.

Adrenal Hyperplasia, Congenital↗
PubMed1988

Immunogenetic heterogeneity of uveal melanoma.

Investigations have been performed to identify genetic markers in uveal melanoma (UM) patients. The immunogenetic heterogeneity of the histologically different forms of UM until now has been little analyzed. We subdivided our UM patients, all typed for class I and II HLA antigens and for Bf polymorphism, into two groups: 1) those with a high degree of malignancy (with nonspindle cells) and 2) those with a low degree of malignancy (with spindle cells). The deviated frequencies of class I HLA antigens (A32, B27) seem to be involved in the predisposition to spindle cell melanoma, while HLA class II (DR3, DR7) and class III (Bf F) strongly mark the worst form of UM. Different Gm allotype distributions between the two histological types of UM were also found.

Gene Frequency↗
PubMed1988

IgA serum levels and HLA complement markers in gastric cancer patients.

Immunoglobulin serum levels and class III HLA polymorphisms (Bf, C4A, and C4B) have been analyzed in 55 gastric cancer patients (13 having at least a first-degree relative affected by the same tumor) from the Republic of San Marino. This was done to search for possible immunoglobulin deficiencies (in particular IgA), which have been proposed to have a prognostic value in gastric cancer, and to identify possible associations between such a tumor and HLA class III determinants. All subjects had normal Ig levels with the exception of one patient (having the worst prognosis) characterized by a combined IgA, IgG, and IgM deficiency. Normal Ig levels were found in all the examined relatives of the proband. The Bf, C4A, and C4B allele frequencies we found did not differ significantly from those reported for healthy subjects in Italian samples.

Alleles↗
PubMed1987

Human leukocyte antigen region involvement in the genetic predisposition to alopecia areata.

Human leukocyte antigens (HLA) of classes I and II were studied in 127 patients with alopecia areata (AA). The patients were subdivided into different groups depending on hair loss area, sex, pathogenesis, response to topical immune modulators (squaric acid dibutylester and diphencyprone) and age of onset of the disease. The frequencies of class I HLA markers (loci A, B, C) were not significantly different from the controls. However, among the class II antigens (loci DR, DQ), the frequency of DR5 was increased in both alopecia areata and alopecia universalis when compared with the control group. In particular, DR5 was strongly linked to the early-onset form. The highest DR5 frequency (62%) was found in the group of patients which presented both the early onset and the most severe form of the disease (p less than 0.01; RR = 3.14). A decrease of the HLA-B8 phenotype frequency was found in the alopecia areata group versus the alopecia universalis one. No significant deviation was found between the female patients and the control group. However, an increase of CW3 and a decrease of DR1 was seen in the males. In the group including 'combined', 'prehypertensive', 'atopic' alopecia of Ikeda's classification the frequency of HLA-A28 and DR5 was increased and that of DR1 was decreased in comparison with the 'common' type of alopecia and the controls. It was not possible to find any relationship between these genetic markers and the response to topical immune modulators.

Adolescent↗
PubMed1977

A new HLA antigen apparently not controlled by the known HLA loci.

The human allogeneic serum RM3 recognizes a lymphocyte structure inherited with the HLA chromosome. Population studies show several positive associations with antigens of the HLA-A and HLA-B series. Negative association have been found with antigens of the HLA-C series. Moreover the distribution of the RM3 factor is in Hardy-Weinberg equilibrium with that of the HLA-C alleles. However, serological investigations (namely the 'lysostrip' technique) bring evidence that RM3 serum does not appear to contain antibodies directed against any of the antigens of the HLA-A, B and C series. The study of a segregant family, showing a crossing over between the HLA-A and HLA-B loci, shows that the RM3 factor segregates on the side of the HLA-A locus. In conclusion, within the limits of the serological approach used, the present study presents evidence of a new serologically defined HLA locus, different from those so far described.

Alleles↗
PubMed1975

On the heterogeneity of linkage estimations between LA and four loci of the HL-A system,.

Three cases of crossing over between the LA and FOUR loci of HL-A system are presented in this note. Recombination fractions between those two loci are also calculated from familial data kindly provided by other European laboratories. It is suggested that differences found in maternal and paternal recombination frequency are due to the heterogeneity of estimates of each laboratory.

Child↗