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Biomedical subjects

M D'Alessandro

Publications and source records attributed to M D'Alessandro.

At least 37 records · Page 2Linked to original sources
PubMed1998

Laparoscopic surgery without pneumoperitoneum.

The results of 43 laparoscopic surgeries performed with an abdominal wall retractor designed in the 3rd Surgical Service at "San Roque" Hospital are analyzed. Of them, 42 underwent cholecistectomy and one an endometrosic focus resection, placed in the Douglas sac. The results obtained have been good. There was almost no postoperatory pain due parietal wall traction. The hospital stay was less than 24 hours in 41 cases and less than 48 hours in two. We also point out the absence of complications and the advantages of the parietal traction compared with pneumoperitoneum.

Adult↗
PubMed1997

The role of immunocytochemistry and linkage analysis in the prenatal diagnosis of merosin-deficient congenital muscular dystrophy.

Complete or partial deficiency of the laminin alpha2 chain of merosin has been demonstrated in a proportion of children with classical congenital muscular dystrophy and linkage to the laminin alpha2 chain gene (LAMA2) on chromosome 6q2 has been established. As the laminin alpha2 chain is also expressed in the trophoblast, its detection and linkage analysis are useful tools for prenatal diagnosis. We report our experience of seven prenatal diagnoses in families with partial deficiency or total absence of the laminin alpha2 chain in the muscle of the propositi. In five instances, expression of the laminin alpha2 chain in the trophoblast was normal and linkage data suggested that the fetuses were unaffected. In one family, the immunocytochemical studies of the trophoblast showed the absence of laminin alpha2, suggesting that the fetus was affected. Linkage analysis confirmed that the fetus had inherited the two at-risk haplotypes. In one family with partial laminin alpha2 chain deficiency, the haplotype analysis was hampered by maternal DNA contamination. Immunocytochemical analysis of chorionic villus sampling showed a reduction in laminin alpha2 expression. The pregnancy was presumed to be at high-risk and terminated. However, subsequent analysis of fetal DNA indicated that the fetus was probably heterozygous. Our data suggest that immunocytochemical analysis of the trophoblast can detect abnormalities in affected fetuses and gives normal results in unaffected and carrier fetuses. Nevertheless, we recommend that linkage analysis to the LAMA2 locus is also studied in all cases.

Female↗
PubMed1997

Late onset muscular dystrophy with cerebral white matter changes due to partial merosin deficiency.

Merosin-deficient congenital muscular dystrophy (CMD) is an autosomal recessive condition usually with onset at birth or within the first months of life. Affected children are severely disabled and usually do not achieve the ability to walk without support. They invariably have white matter abnormalities on brain magnetic resonance imaging (MRI). We report a 29-year-old man with a late childhood onset limb-girdle type muscular dystrophy and cerebral white matter changes on MRI. Immunocyto-chemical studies of the patient's muscle biopsy showed a reduction in expression of the laminin alpha 2 chain of merosin. The patient had three affected siblings, and microsatellite genotyping confirmed linkage to the laminin alpha 2 locus (LAMA2) on chromosome 6q2 in this family. This case probably represents a milder allelic variant of classical merosin-deficient CMD. Merosin status should be assessed in patients with late-onset limb girdle muscular dystrophy.

Adult↗
PubMed1997

Variable clinical phenotype in merosin-deficient congenital muscular dystrophy associated with differential immunolabelling of two fragments of the laminin alpha 2 chain.

Approximately half the cases of classical congenital muscular dystrophy (CMD) have a pronounced deficiency or absence of the laminin alpha 2 chain of laminin-2 (merosin). This is caused by mutations in the LAMA2 gene that codes for laminin alpha 2, and all informative cases so far studied show linkage to the appropriate region on chromosome 6q. Most CMD patients with a deficiency of laminin alpha 2 have a severe phenotype that involves skeletal muscle, and the central and peripheral nervous system. We have identified four cases that have minimal reduction of laminin alpha 2 using a commercial antibody that only recognises a C-terminal 80 kDa fragment, but show a pronounced reduction using an antibody to the 300 kDa fragment. Haplotype analysis is compatible with linkage to the LAMA2 locus in three informative families, whilst the fourth family was not informative. Two of the affected children are ambulant and have a mild phenotype. The third case is unusual in having severe muscle weakness but does not show the white matter changes on magnetic resonance imaging of the brain that is usually seen in merosin-deficient cases of CMD; the fourth case has a severe phenotype, typical of merosin-deficient patients but shows good immunolabelling of the 80 kDa fragment of laminin alpha 2, corresponding to the C-terminal region. Our data show that there is a broad spectrum of phenotype and protein expression associated with a primary deficiency in laminin alpha 2, and that a wider range of clinical cases need to be screened for a deficiency of merosin. It is also important to study the expression of laminin alpha 2 with more than one antibody.

Antibody Specificity↗
PubMed1997

Prenatal diagnosis in merosin-deficient congenital muscular dystrophy.

Prenatal diagnosis was carried out in five merosin-deficient congenital muscular dystrophy (CMD) families. We studied both laminin-alpha 2 chain expression in trophoblast using immunocytochemistry and linkage analysis to the LAMA2 locus. In four families there was good agreement between the immunocytochemistry and linkage analysis results: in one case the trophoblast was negative for LAMA2 expression and haplotype analysis suggested the foetus was affected; in the other three cases the laminin-alpha 2 chain expression was normal and foetuses were found to be carriers. In the remaining family, a case of partial laminin-alpha 2 chain expression, the immunostaining of the trophoblast was weaker compared to the control. Linkage analysis, however, could not be performed because of maternal DNA contamination. After termination of pregnancy, the foetal muscle was studied and suggested weak laminin-alpha 2 chain expression. The haplotype analysis however showed that the foetus was probably a carrier, unless a double recombinant event had occurred. We conclude that a combination of immunocytochemistry and linkage analysis can be used for the prenatal diagnosis of merosin deficient CMD. The results are easy to interpret in families with total absence of the protein, while caution is required when dealing with families where partial expression occurs.

Antibodies, Monoclonal↗
PubMed1997

Expression of laminin chains in skin in merosin-deficient congenital muscular dystrophy.

Laminin-2 (merosin) is a heterotrimer composed of alpha 2, beta 1 and gamma 1 chains. Approximately half of the cases with the classical form of congenital muscular dystrophy (CMD) have a deficiency of the laminin alpha 2 chain, encoded by the LAMA2 gene on chromosome 6q22. This disorder is often termed merosin-deficient CMD. Skeletal and cardiac muscle, and the peripheral and central nervous systems, all express laminin alpha 2 and can be affected in merosin-deficient CMD. Normal skin also expresses all three chains of laminin-2 at the epidermal/dermal junction, around hair follicles and in the sensory nerves. Skin biopsies can therefore be used to assess merosin status in patients. We show here an absence of laminin alpha 2 in skin from four cases of CMD with a severe phenotype and abnormal magnetic resonance image (MRI) of the brain, in contrast to normal expression in one case of mild CMD with normal MRI, and in five controls. An additional case of CMD had a partial deficiency of laminin alpha 2 in the skin and severe motor disability, but a normal MRI. Sensory nerves in this case showed normal expression of laminin alpha 2, in contrast to its absence in the severe cases. The expression of laminin beta 1 was also reduced in skin from cases of merosin-deficient CMD. In contrast to human fetal muscle, the laminin alpha 2 protein was not detected in fetal skin up to 23 weeks of gestation. The laminin beta 1 and gamma 1 chains, and the mRNA for laminin alpha 2, however, were present. Studies of mRNA of cultured skin cells suggest that fibroblasts are the major source of laminin alpha 2, not keratinocytes. Our data show that skin is useful for the assessment of merosin status in patients with CMD and that skin fibroblasts may be a useful source of tissue-specific RNA. In addition, we show that there is a tissue-specific difference in the developmental expression of the laminin alpha 2 protein.

Adolescent↗
PubMed1997

Refinement of the laminin alpha2 chain locus to human chromosome 6q2 in severe and mild merosin deficient congenital muscular dystrophy.

About half of the children with classical congenital muscular dystrophy (CMD) show an absence in their skeletal muscle of laminin alpha2 chain, one of the components of the extracellular matrix protein, merosin. Linkage analysis implicated the laminin alpha2 chain gene (LAMA2) on chromosome 6q2, now confirmed by the discovery of mutations in the laminin alpha2 chain gene. We have further investigated the location of the LAMA2 locus on chromosome 6q2, using both linkage analysis in nine informative families and homozygosity mapping in 13 consanguineous families. Four of these families only had mild or moderate down regulation of laminin alpha2 chain expression and a milder phenotype; the rest had no protein or only a trace. Haplotype analysis in all the informative families, including those with partial laminin alpha2 expression, was compatible with linkage to chromosome 6q2. This observation expands the spectrum of the phenotype secondary to laminin alpha2 chain deficiency. Our results suggest that the LAMA2 locus is more centromeric than previously proposed. Recombinant events place the locus between markers D6S470 and D6S1620 in an interval of less than 3 cM.

Chromosome Mapping↗
PubMed1996

Diagnosis of merosin (laminin-2) deficient congenital muscular dystrophy by skin biopsy.

BACKGROUND: The alpha2 chain of laminin-2 (merosin), encoded by a gene on chromosome 6q22, is deficient in about half the cases of congenital muscular dystrophy. Diagnosis of this condition has relied on immunocytochemical analysis of the alpha2 chain in muscle biopsy specimens. We have observed that normal skin also expresses laminin alpha2 in the basement membrane at the junction of the dermis and epidermis. Here we have investigated laminin alpha2 deficiency in skin biopsy specimens from two patients with congenital muscular dystrophy. PARTICIPANTS: Two patients with severe congenital muscular dystrophy gave informed consent to a skin biopsy. The girl was aged 10 and the boy was aged 7. The specimens were labelled with a commercially available mouse monoclonal antibody and a rat monoclonal antibody (4H8-2), which recognise an 80 and a 380 kDa fragment of the alpha2 chain, respectively. The antibodies were visualised by standard methods. A muscle biopsy specimen was available for each case, and was processed with the skin biopsy samples (from the girl a few months previously, from the boy at age 14 days). Skin biopsies were done on four controls with normal expression of laminin alpha2 on their skeletal muscle fibres. FINDINGS We did not detect laminin alpha2 in skin specimens from either case, although the controls were positive. The muscle biopsy specimens from the girl showed a few fibres, with traces of laminin alpha2; those from the boy showed no laminin alpha2. INTERPRETATION: Skin biopsy specimens will provide a useful alternative to muscle biopsy samples for the assessment of laminin-2 (merosin) status in congenital muscular dystrophy.

Biopsy↗
PubMed1995

Apolipoprotein E in sporadic and familial Creutzfeldt-Jakob disease.

We assessed the apolipoprotein E (ApoE) genotype in 49 sporadic and ten familial Creutzfeldt-Jakob disease (CJD) patients, in seven healthy siblings with a PRNP mutation and in 84 controls. In sporadic CJD, ApoE genotypes and allelic frequencies do not significantly differ from that of controls. No influence of ApoE genotypes on age at onset was found. In familial cases, the disease appeared in mutated subjects showing the same ApoE genotype as members who have not yet developed CJD. Our results provide further evidence that ApoE is not a risk factor for CJD.

Aged↗
PubMed1994

Polymorphisms of the prion protein gene in Italian patients with Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) is a transmissible neurodegenerative disorder characterized by the accumulation of the amyloid protein PrP in the CNS. Two coding polymorphisms of the PrP gene (PRNP) are a methionine (Met) to valine (Val) change at codon 129, and a deletion in the octapeptide coding region. In the United Kingdom, homozygosity at codon 129 appears to be associated with a predisposition to develop CJD. However, in Japan, where allelic frequencies and genotype distribution are significantly different, such an association has not been demonstrated. To determine whether such deletion(s) or codon 129 polymorphisms of PRNP predispose to the development of CJD in Italian patients, 31 sporadic CJD patients with no known PRNP mutations, and 186 unrelated control subjects were studied. Genotypic frequencies at codon 129 in these Italian CJD patients revealed a significant excess of methionine alleles, and a different genotype distribution in comparison with the normal Italian population. Deletions of a 24-bp segment located in the PrP octapeptide coding region were found in two control subjects, but in none of the sporadic CJD patients. These data suggest that Met homozygosity at codon 129 may contribute, with other environmental or endogenous factors, to CJD development.

Adult↗
PubMed1993

Prostaglandin E2 in gastric mucosa of children with Helicobacter pylori gastritis: relation to thickness of mucus gel layer.

AIMS: To evaluate the changes in mucus gel layer thickness and prostaglandin E2 (PGE2) content caused by Helicobacter pylori infection in the antral mucosa of children: to assess whether decreased mucus gel thickness is related to PGE2 production. METHODS: Antral biopsy specimens were taken at endoscopy from 153 children. H pylori gastritis was evident in 45 and normal mucosa in 59. The other 49 children were studied one month after antibiotic treatment that eradicated the infection in 37 of them had been stopped. One antral specimen was immersed in ice-cold saline, put under an inverse microscope with an eyepiece graticule. Mucus gel thickness was measured and then the processed for histological examination; another specimen was weighed and processed for in vitro prostanoid generation. RESULTS: Mucus gel layer thickness was significantly decreased in children with H pylori gastritis (90 (SD) 29) microns v 120 (58) microns in controls, p < 0.01) but returned to control values after H pylori had been eradicated. PGE2 generation was significantly increased in children with H pylori gastritis (1022 (811) ng/g v 641 (473) ng/g in controls, p < 0.01). One month after treatment PGE2 generation significantly decreased in children without infection (880 (534), p < 0.01), but was still high where infection persisted. A significant inverse correlation was found between PGE2 generation and mucus gel layer thickness (p < 0.05). CONCLUSIONS: These data suggest that H pylori damages the mucus gel layer, and that the gastric mucosa increases generation of PGE2 in response to back diffusion of acid and pepsin.

Adolescent↗
PubMed1992

Plasma met-enkephalin in type I diabetes.

Physiological and pathological evidence suggests that opioid peptides may play a role in glucose homeostasis. We measured plasma levels of beta-endorphin (beta-END) and met-enkephalin (met-ENK) in 22 type I diabetic patients and 15 healthy women (control group). No differences were observed in plasma beta-END levels, whereas plasma met-ENK levels were significantly higher (Student's t test, P less than .005) in diabetics than in controls before (68 +/- 3 pg/mL v 32 +/- 7 pg/mL) and 1 hour after, a standard meal and administration of insulin therapy (81 +/- 9 pg/mL v 32 +/- 7 pg/mL). This is the first report of met-ENK levels in insulin-dependent diabetes mellitus (IDDM), and an impaired feedback of insulin/met-ENK is suggested.

Adult↗
PubMed1992

Serum neuron-specific enolase in diagnosis and follow-up of gastrointestinal neuroendocrine tumors.

Neuron-specific enolase (NSE), the glycolytic isoenzyme of the enolase gamma-gamma dimer, is a specific marker for the diffuse neuroendocrine system and derivative tumors (NET). Serum levels of NSE were measured in 39 patients with NET of the gastrointestinal tract (including 3 gastric and 13 intestinal carcinoid tumors, 6 gastrinomas, 3 insulinomas, 1 glucagonoma, 2 mixed islet cell tumors, 11 neuroendocrine pancreatic carcinomas), in 15 healthy subjects and in 15 nonendocrine gastric, pancreatic, and intestinal tumors. Thirty-six of the 39 patients had elevated circulating levels of NSE, 2 insulinomas and 1 gastrinoma had values below 12 ng/ml like healthy subjects and nonendocrine tumors. No significant difference of serum NSE was found between 23 'functioning' and 16 'nonfunctioning' NET. Fourteen of the NET were malignant, and NSE circulating values were significantly higher than those of nonmalignant forms. After curative surgery serum NSE decreased significantly. NSE can be considered a reliable marker in the differential diagnosis between endocrine and nonendocrine neoplasms, in the clinical detection of silent endocrine tumors and in the follow-up of NET.

Adolescent↗