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L Manneschi

Publications and source records attributed to L Manneschi.

At least 19 recordsLinked to original sources
PubMed1999

Dietary determinants of colorectal proliferation in the normal mucosa of subjects with previous colon adenomas.

Dietary determinants of colorectal mucosa proliferation were studied in 69 subjects previously operated for at least two sporadic colon adenomas. Information on recent dietary habits was collected by a validated food frequency questionnaire, and proliferation was measured by [3H]thymidine incorporation in colorectal biopsies by determining the labeling index (LI) and the percentage of LI in the upper part of the crypt, two parameters that are increased in subjects at high risk of colon cancer. The LI was significantly higher in women as compared with men (P = 0.01). Diet showed several associations with colorectal mucosa proliferation: (a) subjects in the highest tertile of fish consumption had a significantly lower LI (P = 0.0013) compared with those in the lower tertiles [5.20 +/- 1.87 versus 6.80 +/- 2.18 (mean +/- SD)]; (b) subjects with a low red meat consumption had lower proliferation in the upper part of the crypt [2.38 +/- 2.10, 5.30 +/- 4.62, and 5.89 +/- 4.82 in the low, middle, and high tertile of consumption, respectively (mean +/- SD); P = 0.0093]; (c) according to estimated nutrient intakes, the LI was lower in subjects reporting a high intake of starch (P = 0.006) and higher in subjects with a low intake of beta-carotene (P = 0.002). The results show that subjects reporting a diet rich in fish, starch, and beta-carotene and low in red meat had lower colorectal mucosa proliferation and a normal pattern of proliferation along the crypt. Given the correlation between colorectal proliferative activity and colon cancer risk, such a dietary pattern might be beneficial for subjects at high risk of colon cancer.

Adenomatous Polyps↗
PubMed1998

A dietary trial with a short-term low-sucrose diet in an Italian population: effects on colorectal mucosal proliferation.

Colorectal mucosal proliferation is supposed to predict colon cancer risk. We investigated whether a low-sucrose diet might reduce colorectal mucosal proliferation in a group of patients at higher risk of colorectal cancer after at least two colon adenoma resections. In a pilot phase, 14 patients [12 men and 2 women, 60.3 +/- 5 (SD) yr] were instructed to adopt a low-sucrose diet for one month. Colorectal biopsies were taken twice in the same patients, at the start and the end of the intervention period, and mucosal proliferation was measured by [3H]thymidine uptake in vitro and autoradiography. Although compliance of study participants to dietary modification was high, only a few agreed to two consecutive endoscopies; thus we carried out a randomized study, and 107 patients were assigned to a low-sucrose diet (50 treated patients: 31 men and 19 women, 59.7 +/- 7.5 yr) or instructed to continue their usual diet for one month (55 control patients: 32 men and 23 women, 59.6 +/- 7.7 yr). At the end of this period, colorectal biopsies were obtained. The results of the pilot phase and the randomized study showed that a low-sucrose diet for one-month did not affect proliferation or the distribution of proliferation activity along the crypt. The food-frequency questionnaires indicated that treated patients consumed significantly less sucrose (and fewer total calories) during the dietary modification. Urinary fructose, a measure of dietary sucrose intake, was also reduced at the end of the intervention period. In conclusion, we found no evidence that a low-sucrose diet for one month influences colorectal mucosal proliferation.

Adult↗
PubMed1998

Association in the same patient of autosomal dominant progressive external ophthalmoplegia with multiple mtDNA deletions and X-linked ichthyosis: clinical, biochemical, histological, submicroscopic and molecular genetic study.

Autosomal dominant chronic progressive external ophthalmoplegia (AdPEO) is a muscle mitochondrial disorder due to multiple large scale rearrangements of the mitochondrial DNA. This disorder is probably due to a nuclear defect which causes genetic instability or an impairment in the replication of mitochondrial DNA. X-linked ichthyosis (XLI) is a skin disorder caused by a deletion in the steroid-sulphatase gene. Here we report the clinical, biochemical, morphologic and molecular genetic findings in a patient affected by both AdPEO, inherited by the father, and steroid-sulphatase-deficiency, inherited by the mother. The association in the same patient of the two inherited diseases is merely casual and does not seem to influence the phenotypic expression of the two diseases.

Aged↗
PubMed1997

Palpebral ptosis and muscle fatiguability associated with perineurial cell ensheathment of muscle fibers: a new disease of the neuromuscular junction?

Perineurial cell ensheathment of muscle fibers has been reported only in one patient. Here we describe a new case with identical morphologic features and a similar, but milder clinical course characterized by progressive muscle weakness and bilateral palpebral ptosis. EMG examination (including repetitive stimulation) and antibodies against acetylcholine receptors were normal. Muscle biopsy revealed several muscle fibers encircled by stratified rings of homogeneous material in which elongated nuclei were visible; this material was positively stained by antibodies directed at epithelial membrane antigen. On ultrastructural examination these encircling-fiber spirals had the characteristics of perineurial cells. It is not clear yet whether perineurial cell ensheathment of muscle fibers is an occasional feature, or whether it has a pathogenetic role in the clinical picture of both cases. The perineurial sheaths might alter the correct neuromuscular transmission mimicking a myasthenia-like disease, either by interfering with the neuromuscular junction, or by changing the microenvironment, and, thus, altering the general excitability of the muscle fibers.

Biopsy↗
PubMed1997

A rare association of myasthenia gravis and mitochondrial myopathy: a clinical, biochemical and morphologic study of one case.

Myasthenia gravis and mitochondrial myopathy may present with similar clinical symptoms as inconstant palpebral ptosis, ophthalmoparesis, and muscle weakness. A few case initially diagnosed as myasthenia gravis by a positive decremental response on EMG and successful anticholinesterase therapy revealed to be affected by mitochondrial disease. We report a new case initially found to be affected by myasthenia gravis in whom muscle biopsy, performed because of symptom worsening, disclosed a mitochondrial myopathy. It is not clear if the association of mitochondrial myopathy and myasthenia gravis is coincidental or if there is a pathogenic link between the two pathologies. We suggest that muscle biopsy should be performed in cases with atypical myasthenia gravis signs.

Aged↗
PubMed1996

Amiodarone affects membrane water permeability properties of human erythrocytes and rat mitochondria.

Dose-dependent water exchange times and intracellular water contents were measured by NMR (nuclear magnetic resonance) in erythrocytes and mitochondria interacted with the anti-anginal and anti-arrhytmic agent, amiodarone. Addition of the drug up to 26 microM yielded 80% enhancement of the water exchange rate in erythrocytes at 37 degrees C and 41% enhancement at 22 degrees C with 40% and 9%, respectively, increases in the intracellular water content. Similar enhancements were obtained in mitochondria at 22 degrees C. The data suggests a somewhat higher affinity of amiodarone to mitochondrial than to erythrocyte membranes.

Amiodarone↗
PubMed1996

The A to G transition at nt 3243 of the mitochondrial tRNALeu(UUR) may cause an MERRF syndrome.

OBJECTIVE: To verify the phenotype to genotype correlations of mitochondrial DNA (mtDNA) related disorders in an atypical maternally inherited encephalomyopathy. METHODS: Neuroradiological, morphological, biochemical, and molecular genetic analyses were performed on the affected members of a pedigree harbouring the heteroplasmic A to G transition at nucleotide 3243 of the mitochondrial tRNALeu(UUR), which is usually associated with the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). RESULTS: The proband was affected by a fullblown syndrome of myoclonic epilepsy with ragged red fibres (MERRF), severe brain atrophy, and basal ganglia calcifications, without the MRI T2 hyperintense focal lesions which are pathognomonic of MELAS. Oligosymptomatic relatives were variably affected by lipomas, goitre, brain atrophy, and basal ganglia calcifications. Muscle biopsies in the proband and his mother showed a MELAS-like pattern with cytochrome c oxidase hyperreactive ragged red fibres and strongly succinate dehydrogenase reactive vessels. Quantification of the A3243G mutation disclosed 78% and 70% of mutated mtDNA in the muscle of the severely affected proband and of his oligosymptomatic mother respectively. Nucleotide sequencing of the mitochondrial tRNALeu(UUR) and tRNALys in the proband's muscle failed to show any additional nucleotide change which could account for the clinical oddity of this pedigree by modulating the expression of the primary pathogenic mutation. CONCLUSION: So far, MERRF has been associated with mutations of the mitochondrial tRNALys, and MELAS with mutations of the mitochondrial tRNALeu(UUR). Now MERRF may also be considered among the clinical syndromes associated with the A to G transition at nt 3243 of the tRNALeu(UUR).

Adolescent↗
PubMed1995

Polarographic analyses of subsarcolemmal and intermyofibrillar mitochondria from rat skeletal and cardiac muscle.

We report the polarographic analysis of subsarcolemmal and intermyofibrillar mitochondria from rat skeletal and cardiac muscle, in order to detect possible biochemical and functional differences. Electron microscopic observation of isolated mitochondria showed normal aspect, with intact membranes. Respiratory control rate with different substrates and state 3 activity did not show differences between subsarcolemmal and intermyofibrillar mitochondria in skeletal muscle and heart.

Animals↗
PubMed1995

Mitochondrial enzyme deficiency in cerebrotendinous xanthomatosis.

We report reduced respiratory chain enzyme activity in isolated muscle mitochondria and high levels of serum and CSF pyruvate and lactate in a case of cerebrotendinous xanthomatosis. These findings raise the question of the pathogenetic role of mitochondrial dysfunction in this syndrome.

Adult↗
PubMed1995

The caecocolonic junction in humans has a sphincteric anatomy and function.

Sphincteric anatomy and function are present at the caecocolonic junction in several mammals. In humans, radiologists and endoscopists have respectively reported a circumferential contraction and a prominent ileocaecal fold at the border area between the caecum and the ascending colon. Anatomical findings on necropsy material failed to confirm its presence. Microscopic studies on surgical specimens showed the existence of muscular and innervational patterns different from those of adjacent areas. The aim of this work was to confirm the existence of a specialised fold at the caecocolonic junction in humans and to ascertain its role by carrying out a study of functional anatomy. Pancolonoscopies were performed on 100 patients and ileocaecal fold behaviour was observed before and after mechanical stimulation. Isolated ileocaecocolonic regions, surgically obtained, were filled with a fixative solution to study their macro and microscopic morphology after stimulation. Endoscopically, the ileocaecal fold was semilunar or circular in shape and spontaneous or evoked spasms occurred in 52 patients. A prominent circular fold could be seen in surgical specimens after stimulation. The entire muscle coat deeply penetrated this fold, showing the features characteristic of the ileocaecal junction. In particular, the inner portion of the circular muscle showed a peculiar arrangement and was thicker than elsewhere. These results show that in humans the caecocolonic junction is provided with a sphincter morphology and function. Little is known about its physiological relevance in ileal flow accommodation and caecal filling and emptying but it should not be underestimated with regard to some colonic motility disorders.

Aged↗
PubMed1990

A mitochondrial encephalomyopathy with specific deficiencies of two respiratory chain polypeptides and a circulating autoantibody to a mitochondrial matrix protein.

A 15-yr-old boy with mitochondrial encephalomyopathy and NADH CoQ reductase (Complex I) deficiency is presented. Immunoblotting demonstrated specific deficiencies of the 24 kDa FeS protein of Complex I and subunit II of Complex IV. The patient's serum contained an antibody to a specific mitochondrial matrix polypeptide of apparent Mr 41 kDa. The specific polypeptide deficiencies involve products of nuclear (24 kDa FeS protein) and mitochondrial (subunit II) genes and suggest some intergenomic regulation. The relevance of the circulating antibody to the pathogenesis of the patient's Complex I deficiency is discussed.

Adolescent↗
PubMed1988

Mitochondrial encephalo-neuro-myopathy with myoclonus epilepsy, basal nuclei calcification and hyperlactacidemia.

We report a new case of MERRF (myoclonus epilepsy with ragged red fibers) syndrome with basal nuclei calcification on the brain CT scan, without hormonal abnormalities, with high CSF protein and hyperlactacidemia, juvenile onset and death at 18 years. Biochemical study of mitochondrial muscle enzymes showed decreased NADH-cytochrome-C-reductase and Succinate-cytochrome C-reductase activity, suggesting a Complex III defect of the respiratory chain. Similar reported cases are reviewed.

Adolescent↗