Search PubMed⌕ Search

Biomedical subjects

C Mariani

Publications and source records attributed to C Mariani.

At least 55 records · Page 3Linked to original sources
PubMed2000

Association of early-onset Alzheimer's disease with an interleukin-1alpha gene polymorphism.

Overexpression of the pluripotent cytokine interleukin-1 (IL-1) by microglial cells correlates with formation of neuritic beta-amyloid plaques in Alzheimer's disease (AD). We evaluated polymorphisms in the genes coding for the IL-1alpha, IL-1beta, and IL-1 receptor antagonist cytokines, and tested their association with the occurrence and age at onset of sporadic AD. We found a strong association between the IL-1A T/T genotype and AD onset before 65 years of age (odds ratio, 4.86), with carriers of this genotype showing an onset of disease 9 years earlier than IL-1A C/C carriers. A weaker association with the age at onset was also shown for the IL-1B and IL-1RN genes. These data suggest either a direct effect of the IL-1 gene family, mainly IL-1A, on the clinical onset of AD, or a linkage dysequilibrium with an unknown locus relevant to AD on chromosome 2.

Adult↗
PubMed1999

Genetic localization of a new locus for recessive familial spastic paraparesis to 15q13-15.

OBJECTIVE: To characterize a new gene locus for familial spastic paraparesis (FSP). BACKGROUND: FSP is a genetically heterogeneous group of upper motor neuron syndromes. It can be inherited as an autosomal dominant, autosomal recessive, or X-linked disorder. Four loci for autosomal dominant FSP have been genetically mapped, and two genes have been shown responsible for the X-linked type. In addition, two loci for autosomal recessive type have been reported and mapped to chromosomes 8q and 16q. The gene for the 16q locus has been characterized as a mitochondrial protein. METHODS: Eight recessive FSP families from America and Europe were used for genetic linkage analysis. The known recessive loci (8q and 16q) and the X-linked loci (PLP and L1CAM genes) were screened through PCR amplification, followed by linkage analysis, single-strand conformational polymorphism, or both. RESULTS: All the families except one revealed lack of linkage to the known loci for recessive and X-linked types of FSP. One of the eight families showed data consistent with linkage to the previously characterized 8q locus. Analysis of all the families for possible linkage to other candidate loci revealed significant positive lod scores for markers in chromosome 15q. The maximum multipoint combined lod score for the non-8q families was Z = 3.14 for markers D15S1007, D15S971, D15S118, and D15S1012, at a distance of 6.41 cM from the marker D15S1007, in between D15S971 and D15S118. CONCLUSIONS: Our data suggest a new locus for recessive FSP linked to chromosome 15q, and that this may be the most common one.

Adolescent↗
PubMed1999

Arabidopsis STERILE APETALA, a multifunctional gene regulating inflorescence, flower, and ovule development.

A recessive mutation in the Arabidopsis STERILE APETALA (SAP) causes severe aberrations in inflorescence and flower and ovule development. In sap flowers, sepals are carpelloid, petals are short and narrow or absent, and anthers are degenerated. Megasporogenesis, the process of meiotic divisions preceding the female gametophyte formation, is arrested in sap ovules during or just after the first meiotic division. More severe aberrations were observed in double mutants between sap and mutant alleles of the floral homeotic gene APETALA2 (AP2) suggesting that both genes are involved in the initiation of female gametophyte development. Together with the organ identity gene AGAMOUS (AG) SAP is required for the maintenance of floral identity acting in a manner similar to APETALA1. In contrast to the outer two floral organs in sap mutant flowers, normal sepals and petals develop in ag/sap double mutants, indicating that SAP negatively regulates AG expression in the perianth whorls. This supposed cadastral function of SAP is supported by in situ hybridization experiments showing ectopic expression of AG in the sap mutant. We have cloned the SAP gene by transposon tagging and revealed that it encodes a novel protein with sequence motifs, that are also present in plant and animal transcription regulators. Consistent with the mutant phenotype, SAP is expressed in inflorescence and floral meristems, floral organ primordia, and ovules. Taken together, we propose that SAP belongs to a new class of transcription regulators essential for a number of processes in Arabidopsis flower development.

Amino Acid Sequence↗
PubMed1999

Observations on dementias with possibly reversible symptoms.

While the evaluation of patients with dementia must also address the possibility of treatable illnesses, recent studies found that reversible diseases are detected in only about 1% of dementia cases. Data on the frequency and evolution of potentially reversible dementias (PRD) in defined clinical settings can be useful in order to optimize diagnostic protocols, thus reducing over-investigation and waste of resources. We reviewed a series of 513 patients (mean age 69.3 +/- 4.2 years, mean education level 7.4 +/- 4.5 years, sex ratio M/F 217/296) referred to a memory clinic by their general practitioner, in order to identify PRD. All the subjects had undergone neurological and neuropsychological examination, and laboratory tests. Patients considered to be demented also underwent CT brain scan. 362 patients (70.6%) met the criteria for dementia. We identified 26 PRD cases (7.2% of dementia cases, 5.1% of the entire sample). In 13 patients (3.6% of dementia cases), a complete clinical and neuropsychological reversal of dementia was seen after treatment. In 5 of them (1.4%), a partial regression was obtained, while 8 showed no improvement. We conclude that potential and actual reversibility do not coincide, and that "true" reversibility is rare (even if not negligible) in clinical practice. Careful clinical history and examination appeared the most useful part of the evaluation to identify PRD. Standard blood tests and vitamin B12 assay were also useful, while CT scan detected PRD causes only in patients with evidence of neurological signs.

Aged↗
PubMed1999

1-aminocyclopropane-1-carboxylate oxidase activity limits ethylene biosynthesis in Rumex palustris during submergence.

Submergence strongly stimulates petiole elongation in Rumex palustris, and ethylene accumulation initiates and maintains this response in submerged tissues. cDNAs from R. palustris corresponding to a 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene (RP-ACO1) were isolated from elongating petioles and used to study the expression of the corresponding gene. An increase in RP-ACO1 messenger was observed in the petioles and lamina of elongating leaves 2 h after the start of submergence. ACC oxidase enzyme activity was measured in homogenates of R. palustris shoots, and a relevant increase was observed within 12 h under water with a maximum after 24 h. We have shown previously that the ethylene production rate of submerged shoots does not increase significantly during the first 24 h of submergence (L.A.C.J. Voesenek, M. Banga, R. H. Thier, C.M. Mudde, F.M. Harren, G.W.M. Barendse, C.W.P.M. Blom [1993] Plant Physiol 103: 783-791), suggesting that under these conditions ACC oxidase activity is inhibited in vivo. We found evidence that this inhibition is caused by a reduction of oxygen levels. We hypothesize that an increased ACC oxidase enzyme concentration counterbalances the reduced enzyme activity caused by low oxygen concentration during submergence, thus sustaining ethylene production under these conditions. Therefore, ethylene biosynthesis seems to be limited at the level of ACC oxidase activity rather than by ACC synthase in R. palustris during submergence.

Aerobiosis↗
PubMed1999

Silencing gene expression of the ethylene-forming enzyme results in a reversible inhibition of ovule development in transgenic tobacco plants

To study the role of ethylene in plant reproduction, we constructed transgenic tobacco plants in which the expression of a pistil-specific gene coding for the ethylene-forming enzyme 1-aminocyclopropane-1-carboxylate oxidase was inhibited. Flowers from transgenic plants showed female sterility due to an arrest in ovule development. Megasporogenesis did not occur, and ovules did not reach maturity. When pollinated, pollen tubes were able to reach the ovary but did not penetrate into the immature ovule in transgenic plants. Flower treatment with an ethylene source resulted in a functional recovery of ovule development and restored guidance of the pollen tube tip into the ovule micropyle that resulted in seed set. The recovery was abolished if inhibitors of ethylene action were present. These results demonstrate that the plant hormone ethylene is required during the very early stages of female sporogenesis and ultimately to enable fertilization.

Journal Article↗
PubMed1999

Hydrocortisone levels in the urine and blood of horses treated with ACTH.

An investigation was undertaken to demonstrate whether therapeutic treatment with ACTH raises hydrocortisone (cortisol) levels in horse urine above the limit (1000 ng/ml) established by the International Conference of Racing Authorities with the aim of controlling the abuse of cortisol and ACTH in equine sports. ACTH (200 iu) was administered i.m. to 3 Thoroughbred horses; urine and blood samples were collected at intervals afterwards and analysed by an immunoenzymatic system (ELISA) and HPLC-MS. To ascertain post exercise cortisol levels in untreated horses, 101 urine and 103 serum samples were taken from horses immediately after racing and analysed by ELISA. The peak urine level of cortisol, detected 8 h after ACTH administration, was around 600 ng/ml using either ELISA or HPLC-MS. The peak serum cortisol concentration was found to be around 250 ng/ml by ELISA, but consistently less by HPLC-MS. Mean cortisol levels in post race horses were 135.1+/-72.1 ng/ml in urine and 90.1+/-41.7 ng/ml in serum. High levels of the metabolite 20beta-dihydrocortisol in urine and the cortisol precursor 11beta-desoxycortisol in serum were found. The latter showed high cross-reactivity with cortisol on ELISA. In our experiment, treatment with ACTH 200 iu i.m. did not raise urinary cortisol levels above the 1000 ng/ml threshold proposed by the ICRA.

Adrenocorticotropic Hormone↗
PubMed1999

T1 and T2 in the brain of healthy subjects, patients with Parkinson disease, and patients with multiple system atrophy: relation to iron content.

PURPOSE: To investigate the potential of magnetic resonance imaging for identification and quantification of brain iron in healthy subjects, patients with Parkinson disease, and patients with multiple system atrophy. MATERIALS AND METHODS: Forty-nine subjects were studied at 1.5 T. Regional T1 and T2 values were compared among groups and also with histopathologic estimates of iron concentration. RESULTS: In healthy subjects, interregional T1 and T2 differences in the cortex and basal ganglia showed a good correlation with reported values for iron concentration, and intraregional variations were generally consistent with reported variability of iron concentration. Patients with multiple system atrophy had T1 and T2 shortening in the globus pallidus consistent with reported increases in ferritin-bound iron and changes in the putamen consistent with accumulation of hemosiderin (posterior portion) and neuromelanin (remainder). Both groups of patients had changes in the cortex that are consistent with decreased ferritin concentration and T2 changes in white matter consistent with demyelination. Patients with Parkinson disease also had a (nonsignificant) T2 shortening in the substantia nigra that was suggestive of iron accumulation. CONCLUSION: Most of the T1 and T2 findings appear to be related to changes in iron content and form and may possibly be used as indicators of such changes.

Aged↗
PubMed1999

Determination of substances of abuse in biological fluids by GC/MS using chemical ionization with acetonitrile.

GC/ms is an important method to determine drugs in biological fluids. For each of the most commonly used drugs a methanolic solution (100 micrograms/ml) was prepared; 30 microliters of each solution was evaporated using nitrogen flow and than diluted in 100 microliters of a derivatizing mixture constituted by MSTFA and toluene (30/70). After a short reaction time at room temperature 1 ml of each solution was injected into a SE-52 column (15 m x 0.25 mm) using chemical ionization with acetonitrile. This method has a good signal/noise ratio and is very useful in screening techniques.

Acetonitriles↗
PubMed1998

Development of phagocytic function of cultured human monocytes is regulated by cell surface IL-10.

Monocytes differentiating in vitro into macrophages increase their capacity to ingest particles via FcgammaR and CR3. Because human recombinant IL-10 is a potent up-regulator of phagocytosis in human monocytes, we investigated whether spontaneously produced IL-10 could be a signal for the modulation of phagocytosis by cultured monocytes. We show here that culture of monocytes in the presence of anti-IL-10 mAb completely abolished up-regulation of phagocytosis of both EIgG and EIgMC3bi, suggesting a role for spontaneously produced IL-10 in the modulation of phagocytosis by cultured human monocytes. The inhibition exerted by anti-IL-10 mAb on the development of FcgammaR-mediated ingestion was dependent on the concomitant inhibition of FcgammaRIII induction in cultured cells. On the other hand, a similar down-regulation of CR3 expression was not involved in the inhibitory effect exerted by anti-IL-10 mAb on the development of CR3-mediated ingestion. Monocytes secreted detectable levels of IL-10 when cultured in medium but the concentrations of IL-10 in the supernatants decreased with length of time in culture, the decrease being completely reversed by anti-IL-10 mAb. In addition, we showed that monocytes expressed immunoreactive IL-10 on their surface and this expression increased during differentiation into macrophages. Whether this IL-10 was bound to specific membrane receptors or it was an integral membrane protein remains to be determined; however, this latter possibility is consistent with our observations that IL-10 did not elute with acid treatment and exogenous IL-10 did not increase surface staining of monocytes. Our data indicate that human mononuclear phagocytes express IL-10 on their membrane and suggest that this cytokine may represent an autocrine signal for the increased phagocytic function observed during differentiation of monocytes into macrophages.

Antibodies, Monoclonal↗
PubMed1998

Lipids are required for directional pollen-tube growth.

Successful pollination and fertilization are absolute requirements for sexual reproduction in higher plants. Pollen hydration, germination and penetration of the stigma by pollen tubes are influenced by the exudate on wet stigmas and by the pollen coat in species with dry stigmas. The exudate allows pollen tubes to grow directly into the stigma, whereas the pollen coat establishes the contact with the stigma. Pollen tubes then grow into the papillae, which are covered by a cuticle. The components of the exudate or pollen coat that are responsible for pollen tube penetration are not known. To discover the role of the exudate, we tested selected compounds for their ability to act as functional substitutes for exudate in the initial stages of pollen-tube growth on transgenic stigmaless tobacco plants that did not produce exudate. Here we show that lipids are the essential factor needed for pollen tubes to penetrate the stigma, and that, in the presence of these lipids, pollen tubes will also penetrate leaves. We propose that lipids direct pollen-tube growth by controlling the flow of water to pollen in species with dry and wet stigmas.

Arabidopsis↗
PubMed1998

A tobacco flower-specific gene encodes a polyphenol oxidase.

Identification of pistil-expressed genes is an important step in understanding pistil development and function in plant reproduction. A tobacco stigma/style cDNA library was differentially screened and several cDNA clones were isolated. One of these tobacco genes, designated tobP1, is characterized here. TobP1 encodes a protein highly homologous to plant polyphenol oxidases. Northern blot analysis of total RNA extracted from different organs and probed with tobP1 cDNA identified a single transcript that is exclusively present in flower organs (petals, stamens, and predominantly in pistils). The tobP1 gene is co-ordinately regulated during development in pistils and stamens, and is not induced in mature leaves even under stress conditions. TobP1 belongs to a multigene family, as reported for PPO in other plant species.

Amino Acid Sequence↗
PubMed1997

Acid-base balance and O2 transport at high altitude.

Ear lobe blood pHa, PaCo2, PaO2, and O2 saturation (SaO2) were measured in healthy Caucasians and Sherpas at 3400 m (Namche Bazaar, Nepal, n = 4/5), 5050 m (Pyramid Laboratory, Lobuche, Nepal, n = 20/5) and 6450 m (Camp II of Mt Everest, n = 11/7). In the investigated altitude range, pHa increased progressively with altitude from 7.463 +/- 0.005 (mean +/- SE) to 7.496 +/- 0.006 in Caucasians whereas it remained essentially constant (7.45-7.46) in Sherpas. At all altitudes, PaCO2 was higher in Sherpas than in Caucasians (P < 0.02). By contrast, PaO2 and SaO2 were the same in Caucasians and Sherpas at all investigated altitudes. Moreover, in Caucasians sojourning for 3 weeks at 5050 m, PaCO2 kept decreasing whereas pHa, PaO2 and SaO2 remained constant. These data suggest that; (1) respiratory alkalosis was a common finding both in Caucasians and Sherpas; (2) at 6450 m. Sherpas were less alkalotic due to higher PaCO2 than Caucasians, possibly a consequence of a blunted ventilatory response; (3) at 6450 m, SaO2 and PaO2 were the same in Caucasians and Sherpas despite different PaCO2 values. The latter finding could be the consequence of one or more of the following adjustments in Sherpas: (1) an increased efficiency of alveolar O2 transfer, i.e. smaller alveolar-arterial O2 gradient; (2) a decreased (arterial-mixed venous) O2 difference possibly due to increased cardiac output; (3) a reduced increase of the [2,3-DPG]/[Hb] ratio; but not (4) an elevated gas exchange ratio (R). It is concluded that both physiological and biochemical variables contribute to optimize the O2 transport at altitude. Apparently a more efficient adaptation to hypoxia allows Sherpas to limit alkalosis through a lower ventilatory drive and to maintain SaO2 at the same PaO2 by decreasing the [2,3-DPG]/[Hb] ratio.

2,3-Diphosphoglycerate↗
PubMed1997

A homolog of the Arabidopsis thaliana ERS gene is actively regulated in Rumex palustris upon flooding.

A cDNA homologous to the ethylene-response sensors (ERS/ETR1) from Arabidopsis thaliana was isolated from a Rumex palustris cDNA library. This cDNA, RP-ERS1, was 2421 bp long and shared 66% nucleotide homology with ETR1 and ERS in their coding regions. The transcript level of RP-ERS1 was actively regulated during the leafelongation response of R. palustris upon flooding. RP-ERS1 transcript levels increased after submergence, and also after exposure to high concentrations of ethylene and carbon dioxide and low concentrations of oxygen. These results suggest that R. palustris plants may respond to flooding stress by increasing the number of their ethylene receptors.

Amino Acid Sequence↗
PubMed1997

Neuropsychological deficits in asymptomatic atrial fibrillation.

OBJECTIVE: To assess the preclinical effects on cognitive functions of nonrheumatic atrial fibrillation (NRAF) in patients with negative history for cerebrovascular disease. MATERIALS AND METHODS: The study included 37 consecutive patients with chronic (n=16, mean age 65.3+/-6.6 years) or paroxysmal (n=21, mean age 58.3+/-9.5 years) NRAF and an equal number of control subjects in sinus rhythm, who were matched for age, education and presence of hypertension. A comprehensive neuropsychological battery including tests of attention, memory, language and visuospatial skills was administered. RESULTS: Patients with chronic NRAF showed significantly poorer performances in tasks exploring attention and verbal memory functions, while the paroxysmal group was significantly impaired in a long-term memory task. The neuropsychological findings were confirmed excluding from both groups patients with CT evidence of cerebrovascular damage. A small subgroup of patients was also submitted to cerebral MRI. CONCLUSION: Neurologically asymptomatic NRAF is related to a subclinical but significant impairment in attention and memory. These deficits could be produced by minor ischemic lesions due to microembolization, or by diffuse hypoxic damage due to hypoperfusion.

Adult↗