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Biomedical subjects

M G Marrosu

Publications and source records attributed to M G Marrosu.

14 recordsLinked to original sources

Variable dystrophin expression in different muscles of a Duchenne muscular dystrophy carrier.

The majority of Duchenne muscular dystrophy (DMD) female carriers show dystrophin immunostaining abnormalities, although a significant proportion of clinically non-manifesting carriers are normal following this analysis. We had the opportunity to study dystrophin immunostaining in two different muscles, the vastus lateralis and the rectus abdominis of a possible DMD carrier. While the vastus showed normal dystrophin immunostaining, pathological staining was detected in her rectus abdominis. These findings seem to indicate that dystrophin expression can vary in different muscle groups of a DMD carrier. The implications of these findings in DMD carrier detection and possible dystrophin function are discussed.

Adult

Polymerase chain reaction analysis for specific HTLV-1 sequences from cerebrospinal fluid and peripheral blood cells in Sardinian multiple sclerosis patients.

Using polymerase chain reaction and specific primers, we found no gag and env sequences of HTLV-1 in DNA samples from peripheral blood mononuclear cells of 26 multiple sclerosis (MS) patients with relapsing-remitting, relapsing-progressive and progressive course from onset of the disease, and from 8 patients affected with other neurological diseases (OND). A Positive signal for the gag region was found in DNA samples from cerebrospinal fluid mononuclear cells (CSFMC) of 6/17 (27.3%) MS patients (either with relapsing-remitting, or relapsing-progressive and progressive course from onset of the disease), and in 2/11 (18.2%) CSFMC OND samples. Positive hybridization for the env sequence was evident in 2/11 (18.2%) CSFMC from OND and none of MS samples. The finding of positive hybridization for gag and env sequences in a few samples of CSFMC may be related to the presence in the CSF of a great number of activated cells, which could express cross-reacting sequences of endogenous retrovirus.

Adolescent

HLA-DQB1 genotype in Sardinian multiple sclerosis: evidence for a key role of DQB1 *0201 and *0302 alleles.

We studied HLA-DQB1 haplotypes in 103 unrelated multiple sclerosis (UMS) patients and in 26 related (RMS) patients from 12 families from Sardinia, Italy, where the disease was associated with the HLA-DR4 allele. Using polymerase chain reaction and allele-specific oligonucleotide probes, we found in UMS an increased frequency of the DQB1 *0201 (p = 0.010) and DQB1 *0302 (p = 0.025) alleles, whereas the DQB1 *0301 allele was significantly decreased (p = 0.027). In RMS, only the DQB1 *0302 allele was increased (p = 0.047), and no difference was found in the DQB1 *0301 allele. For DQB haplotypes, an increased frequency of DQB1 *0302/*0502 (p = 0.026) and a decreased frequency of DQB1 *0201/*0601 (p = 0.009) and DQB1 *0502/*0502 (p = 0.025) was found in UMS patients, whereas RMS patients showed an increased frequency of DQB1 *0301/*0302 (p = 0.005). Because DQB1 *0201 and *0302 alleles are increased in Caucasian MS patients, where the disease is related to HLA-DR2 and where a primary association with the HLA-DR2, DQB1 *0602 allele has been reported, we conclude that Caucasian and Sardinian populations share HLA-DQB1 *0201 and *0302 alleles in genetic susceptibility to MS.

Alleles

Decrease in memory (CDw29-high) cerebrospinal fluid cells from acute MS patients.

The CD45R (2H4) and CDw29 (4B4) molecules are probably involved in the regulation of immunological memory: CD45R functionally defines naive or virgin cells (prior to activation by exposure to antigen), while CDw29 characterizes previously activated (memory) cells. By means of two-colour fluorescence analysis, we studied CD4 and CD8, CD45R and CD4 and CD8 CDw29 cells from the cerebrospinal fluid (CSF) of 27 acute (MSa), and 10 stable (MSs) multiple sclerosis (MS) patients. We also compared 17 patients affected with various non-inflammatory (OND) diseases of the central nervous system (CNS). The most striking finding was the increased percentage of CD4+CD29-, CD4+CD45R- and CD8+CD45R- cells and the decreased percentage of CD4-CDw29+ and CD8- CDw29+ subsets in MSa patients compared to OND and MSs populations. These data suggest a decrease in memory cells (CDw29+) during the acute phase of MS. The modulation of CDw29 receptor could play a role in the genesis of acute MS attacks.

Adolescent

Sardinian multiple sclerosis is associated with HLA-DR4: a serologic and molecular analysis.

HLA haplotypes in 45 unrelated Sardinian multiple sclerosis patients and in six multiplex families were defined, using both serologic and restriction fragment length polymorphism (RFLP) analysis. In unrelated MS patients, we found an association with HLA-DR4 (p less than 0.01, relative risk = 2.5) and DQw3 (p less than 0.04, relative risk = 2.2). Using a beta-DR cDNA probe, we observed no variation of the DR4 RFLP profile in sporadic or related MS patients compared with DR4-specific pattern in controls. Using a beta-DQ cDNA probe, we identified two DQw3 patterns (DQw3.1 and DQw3.2) with similar frequency in patients and in controls. No specific RFLPs were observed in association with different disease courses. The frequency of haplotype sharing in affected members of multiplex families was not different from that expected by chance. This study shows that Sardinian MS patients carry predominantly the HLA-DR4 allele, in contrast to the DR2 prevalence reported in Caucasian populations. The lack of association with HLA haplotypes in affected members of multiplex families may indicate that genetic factors outside the HLA system play a substantial role in families with MS.

Adult

Lymphocyte subsets at different stages of subacute sclerosing panencephalitis: a study with monoclonal antibodies.

Lymphocyte subsets in cerebrospinal fluid (CSF) and peripheral blood were studied using monoclonal antibodies, in patients with subacute sclerosing panencephalitis, eight of whom were at stage 2 and seven at stage 4. Eighteen subjects affected with non immunological diseases constituted the controls. Regardless of the stage, patients with subacute sclerosing panencephalitis had lower percentages of OKT3+ (pan-T) cells in both CSF and peripheral blood, with an increase of OKIa+ cells (B cells, macrophages and active T cells) in peripheral blood. A difference was found in the proportion of OKT4+ (helper-inducer) and OKT8+ (suppressor/cytotoxic) cells in relation to the stage, the most striking finding being a significant decrease of OKT8+ with an increase of T4/T8 ratio in peripheral blood at an early stage.

Antibodies, Monoclonal

Alpha-naphthyl acetate esterase activity in human lymphocytes: distribution in lymphocyte subpopulations and in mitogen-activated cells.

The cytochemical demonstration of nonspecific alpha-naphthyl acetate esterase (ANAE) activity in human peripheral blood mononuclear cells was studied. Different staining patterns were found, allowing differentiation of mononuclear cells into macrophages (strong granular cytoplasmic activity), B lymphocytes (negative reaction), Tgamma lymphocytes, i.e. bearing IgG Fc receptors (granular scattered reaction), and T non-gamma lymphocytes, i.e. devoid of IgG Fc receptors (single cytoplasmic ANAE spot). During the early phases of phytohaemagglutinin (PHA)- and concanavalin A (Con A)-induced activation, the reactivity of most lymphocytes became granular and scattered, similar to that found in Tgamma cells. Blast cells generating in successive phases appeared devoid of detectable enzymatic activity. The hypothesis is put forth that T cells showing granular, scattered reactivity represent a population of activated cells and that the redistribution of enzymatic activity could represent a preliminary step leading to secretion (lymphokine-like?) of enzyme from cytoplasm in the course of cell activation.

B-Lymphocytes

Surface markers on lymphocytes from human cerebrospinal fluid. Predominance of T lymphocytes bearing receptors for the Fc segment of IgG.

Surface markers of cerebrospinal fluid (CSF) cells have been studied in comparison with those of peripheral blood lymphocytes. The great majority (about 95%) of CSF cells bear surface markers of thymus-dependent lymphocytes (E rosettes with uncoated sheep red blood cells), while being devoid of bone-marrow derived cell markers (EAC rosettes with complement-coated red blood cells). In contrast with lymphocytes from peripheral blood, CSF cells form predominantly 'early' and 'sphere'-shaped E rosettes, and bear receptors for the complement-fixing segment of immunoglobulins G. Treatment with concentrated CSF does not affect rosette forming ability of peripheral blood lymphocytes.

Cerebrospinal Fluid

Premutation for the Martin-Bell syndrome analyzed in a large Sardinian family: II. Neuropsychological and behavioral data.

We describe the neuropsychological and behavioral profiles of 48 critical members of a previously reported Sardinian pedigree [Filippi et al., 1991], in which the fully manifested Martin-Bell syndrome (MBS), observed among males of the latest generations, is clearly the result of step-wise mutational events occurred repeatedly along the X-chromosome pathway linking all of them to a common ancestress, who must have been heterozygous for a fragile X (FRAX) premutation. We found that the unquestionable presence in the family of normal transmitting males and females could not be determined on the basis of neuropsychological and behavioral data alone. However, we think that the large variation observed in the expression of most diagnostic parameters among the MBS patients and their close female relatives in this family, could by itself be a connotation of the genome instability which characterizes the FRAX region in pedigrees segregating for the FRAX premutation(s) and mutation(s).

Behavior

X-linked mental retardation and characteristic physical features in two brothers with duplication Xp22-Xpter.

Two brothers are reported who share mental retardation, conjunctival teleangectasias (mainly equatorial) and characteristic flat face with small mouth and thin prolabia. At the neuropsychological examination, the older brother at 14 years showed a full scale IQ of 40 (WISC), with verbal IQ 45 and performance IQ 44. The younger brother at 7 years showed a full scale IQ of 58 (WPPSI), with verbal IQ 67 and performance IQ 55. Chromosome studies showed a duplication Xp22-Xpter in both brothers and in the inactivated X of their mother. The anomaly was not present in a 3rd healthy brother and in other healthy relatives. The mother has normal intelligence and did not present any of the physical features of her affected sons.

Adolescent

Neuropsychological studies in families with fragile-X negative X-linked mental retardation.

Neuropsychological studies were performed in 82 subjects of 12 families with x-linked, fragile X negative, mental retardation (MR). Subjects were examined with Wechsler tests (WPPSI, WISC-R or WAIS, according to their capabilities), Progressive Matrices, Bender or Santucci and memory tests. Physical findings in 5 families were characterised by micro-orchidism (MiO), microcephaly (MiC), short stature (SS) and non-specific facial features (XMR +/- MiO +/- MiC +/- SS). The 11 males with MR had a very low IQ, ranging from 13 to 37 (mean 21.2 +/- 8.8); this did not constitute a profile definition. Among the females of their families, 4 had subnormal or borderline IQ, respectively 74, 66, 38 and 37. A second group (2 families) had MiO but with normal stature and occipito-frontal circumference (XMR +/- MiO). The 7 males with MR had an IQ ranging from 24 to 43 (mean 35.1 +/- 5.8) and showed frequently better results in performance than in verbal subtests. In these 2 families, 5 females had subnormal or borderline IQ, respectively 77, 72, 71, 70 and 20. In the 5 families of the third group, XMR +/- MaO (fraX-), several affected males had macro-orchidism (MaO) and facial changes similar to those of fragile X syndrome. IQ variability, also in the same family (e.g.: the 3 brothers of family 3 had, respectively, an IQ of 26, 28 and 68; and 2 brothers of family 1 had an IQ of 13 and 63) and different profiles. Two females were severely affected (IQ 16 and 24), while another 4 had an IQ, respectively, of 63, 69, 71 and 72.

Adult