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Biomedical subjects

M Nigro

Publications and source records attributed to M Nigro.

At least 19 recordsLinked to original sources
PubMed2006

Effects of algal extracts (Polysiphonia fucoides) on rainbow trout (Oncorhynchus mykiss): a biomarker approach.

The genotoxicity of algal extracts (Polysiphonia fucoides) was investigated in erythrocytes of rainbow trout (Oncorhynchus mykiss). Trout were exposed to 0.5% of the algal extract for 7 days. Comet assay (alkaline and neutral versions) and Micronucleus test were used to assess DNA damage, and Diffusion Assay to detect apoptotic cells. EROD activities and oxidative stress parameters in rainbow trout liver were also measured. A significant induction of DNA single strand breaks comparable to the ones induced by the in vivo exposure to 20 mg/kg B[a]P was observed at the end of the treatment, while increases of double strand breaks and apoptotic cells were not observed. The absence of activation of antioxidant responses seems to underline a mechanism of action of the genotoxic algal extract which does not involve oxidative stress.

Animals↗
PubMed2006

Cellular biomarkers for monitoring estuarine environments: transplanted versus native mussels.

In developed countries, estuarine environments are often subjected to chemical pollution, whose biological impact is profitably evaluated by the use of multi-biomarker approaches on sentinel species. In this paper, we investigate genotoxicity and lysosomal alterations in the Mediterranean mussel (Mytilus galloprovincialis), from the estuary of the River Cecina (Tuscany, Italy), selected as "pilot basin" within the Water Frame Directive (2000/60 European Community). Both native and 1 month transplanted mussels were used in order to compare these two approaches in terms of sensitiveness of specific biomarker responses. Genotoxic effects were evaluated as strand breaks, by single cell gel electrophoresis (or Comet assay), and as chromosomal alterations, by the micronucleus test in gill cells. Lysosomal alterations were assessed by the neutral red retention time (in haemocytes), lipofuscin accumulation and ultrastructure (in digestive cells). Heavy metal bioaccumulation was also analysed. Mussels from the River Cecina showed a general alteration of all the biomarkers investigated, accompanied by an elevation of tissue metal levels. However, some differences in specific responses occurred between transplanted and native mussels. Early biomarkers, such as those based on DNA and lysosomal membrane integrity, were induced at similar degree in native and transplanted mussels; while alterations resulting from cumulative events, as the increase of micronuclei frequency were much more elevated in native specimens (23.1+/-7.6) than in transplanted (9.3+/-4.7) and reference ones (5.8+/-5.2). Similarly, the comparison between lipofuscin accumulation and mean lysosomal diameter in impacted and control sites, gave significant differences exclusively with transplanted mussels. These results suggest that the parallel use of caged and native mussels in environmental biomonitoring can improve the characterization of the study area.

Animals↗
PubMed2003

DNA damage and ubiquitinated neuronal inclusions in the substantia nigra and striatum of mice following MDMA (ecstasy).

RATIONALE: 3,4-Methylenedioxymethamphetamine (MDMA) is an amphetamine derivative, which is neurotoxic to both serotonin (5HT) and dopamine (DA) nerve terminals. Previous reports, carried out in rodents and non-human primates, demonstrated neurotoxicity to monoamine axon terminals, although no study has analyzed nigral and striatal cell bodies at the sub-cellular level. OBJECTIVE: In this study, we examined intrinsic nigral and striatal cells, and PC12 cell cultures to evaluate whether, in mice, MDMA might affect nigral and striatal cell bodies. METHODS: After administering MDMA, we analyzed effects induced in vivo and in vitro using high-performance liquid chromatography (HPLC) analysis, light- and electron microscopy with immunocytochemistry, and DNA comet assay. RESULTS: We found that MDMA (5 mg/kg x4, 2 h apart), besides a decrease of nigrostriatal DA innervation and 5HT loss, produces neuronal inclusions within nigral and intrinsic striatal neurons consisting of multi-layer ubiquitin-positive whorls extending to the nucleus of the cell. These fine morphological changes are associated with clustering of heat shock protein (HSP)-70 in the nucleus, very close to chromatin filaments. In the same experimental conditions, we could detect oxidation of DNA bases followed by DNA damage. The nature of inclusions was further investigated using PC12 cell cultures. CONCLUSIONS: The present findings lead to re-consideration of the neurotoxic consequences of MDMA administration. In fact, occurrence of ubiquitin-positive neuronal inclusions and DNA damage both in nigral and striatal cells sheds new light into the fine alterations induced by MDMA, also suggesting the involvement of nuclear and cytoplasmic components of the ubiquitin-proteasome pathway in MDMA toxicity.

Animals↗
PubMed2002

Seasonal variations of susceptibility to oxidative stress in Adamussium colbecki, a key bioindicator species for the Antarctic marine environment.

The area of free radical biology is of increasing interest for marine organisms since the enhanced formation of reactive oxygen species (ROS) is a common pathway of toxicity induced by stressful environmental conditions. In polar environments responses of the antioxidant system could be useful as an early detection biomarkers of unforeseen effects of human activities which are progressively increasing in these remote areas. However, the characterization of antioxidant defences in appropriate sentinel species is of particular value also in terms of a possible adaptation to this extreme environment. The scallop, Adamussium colbecki, is a key species for monitoring the Antarctic environment and, besides single antioxidants, the total oxyradical scavenging capacity (TOSC) assay has been recently used for quantifying the overall ability of this organism to neutralize peroxyl radicals (ROO*), hydroxyl radicals (*OH) and peroxynitrite (HOONO). The aim of this work was to obtain a better characterization of these biological responses which can indicate the occurrence of biological disturbance; in this study the total oxyradical scavenging capacity was further analyzed to assess the presence of seasonal fluctuations in the susceptibility to oxidative stress in this species. The capability to neutralize peroxyl radicals and hydroxyl radicals increased at the end of December, while resistance towards peroxynitrite did not show any significant variations during the Antarctic summer. These results suggest the occurrence of metabolic changes which mainly influence intracellular formation of ROO* and *OH, with more limited effects on HOONO. Despite the limited time window analyzed, as a typical constraint in Antarctic research at Terra Nova Bay, an increased resistance to these specific oxyradicals might be related to the period of highest feeding activity, or to other intrinsic factors in the animals' physiology such as the phase of reproductive cycle.

Adaptation, Physiological↗
PubMed2002

Mercury exposure and elimination rates in captive bottlenose dolphins.

Mercury concentrations in fish, faeces and exhaled air were investigated in order to evaluate total mercury exposure through the gut in captive bottlenose dolphin and excretion via intestine and pulmonary routes. Results showed that faeces account for elimination of 34-48% of dietary mercury; while only 0.9-1.2% of alimentary mercury is eliminated through exhaled air. The remaining 51.2-65.3% of ingested mercury, ranging approximately between 266 and 339 microg per day, is retained within the organism. The complexation of mercury with selenium, forming insoluble tiemannite granules, is discussed as an important mechanism, complementary to excretion, by which odontocetes are able to cope with elevated alimentary exposure to mercury.

Animals↗
PubMed2002

Acute encephalopathy with parvovirus B19 infection in sickle cell disease.

A 13 year old girl with haemoglobin Sbeta(+)thalassaemia developed simultaneous aplastic crisis and encephalopathy associated with parvovirus B19 (PB19) infection. Brain magnetic resonance imaging findings were consistent with central nervous system (CNS) vasculitis and her symptoms resolved with steroid therapy. Thus, PB19 induced CNS hypersensitivity vasculitis must be considered in the differential diagnosis of encephalopathy.

Acute Disease↗
PubMed2001

Genotoxic hazard of pollutants in cetaceans: DNA damage and repair evaluated in the bottlenose dolphin (Tursiops truncatus) by the Comet Assay.

Single cell gel electrophoresis (or Comet Assay) was used for evaluation of the in vitro genotoxicity of hydrogen peroxide (used as a positive control), polychlorinated biphenyls (PCBs) (Aroclor 1254) and methyl mercury chloride, in isolated bottlenose dolphin leukocytes. Results showed that hydrogen peroxide and methyl mercury induced DNA strand breakage in a dose-dependent manner, while PCBs did not induce a clear dose-effect response at the low doses investigated. Efficiency in repairing DNA breakage induced by methyl mercury was also evaluated. Findings demonstrated that dolphin cells are characterized by higher efficiency in DNA repair when compared to human leukocytes. The observed resistance to methyl mercury toxicity in dolphins was hypothesized to be a defence strategy developed to combat high dietary exposure and compensate for limited capacity to excrete persistent pollutants.

Animals↗
PubMed2001

DNA integrity and total oxyradical scavenging capacity in the Mediterranean mussel, Mytilus galloprovincialis: a field study in a highly eutrophicated coastal lagoon.

In Mediterranean coastal lagoons, the combination of human impact and wide variability of natural environmental factors can lead to upsets in ecosystem homeostasis resulting in biodiversity decline. Oxidative damage has been causally linked to various kinds of environmental stress, both natural and artificial, the result being impairment of cellular functions. DNA damage and the efficiency of antioxidant defences in Mytilus galloprovincialis from the highly eutrophicated Orbetello Lagoon (Tuscany, Italy) were investigated, respectively by the single cell gel electrophoresis (or Comet test) and the total oxyradical scavenging capacity assay. Results showed significantly higher levels of DNA damage in mussels collected from the inner parts of the lagoon compared to specimens from more external sites. Specimens with the lower genetic integrity also exhibited a reduced efficiency in neutralizing three potent cellular oxidizing species, namely peroxyl radicals (ROO*), hydroxyl radicals (*OH) and peroxynitrite (HOONO), suggesting the involvement of reactive oxygen species in mediating the genetic damage. The analyzed biological parameters also showed a seasonal variability with a minimum of both DNA integrity and antioxidant scavenging efficiency during the warm months and an opposite trend in winter. The potential of analyzed techniques is discussed for the assessment of both anthropogenic and natural disturbance.

Animals↗
PubMed2001

High level of expression of the Toxoplasma gondii-recombinant Rop2 protein in Escherichia coli as a soluble form for optimal use in diagnosis.

The rhoptry 2 protein (Rop2) is an interesting protein of Toxoplasma gondii that is involved in the parasite invasion of host cell, it has three T-cell epitopes and high antigenic value. However, the expression of Rop2 as a recombinant protein in Escherichia coli is not an easy task, showing low levels of expression or degradation and solubility problems. Using a recombinant Rop2(196-561) fused to 6 histidine residues, we showed high levels of expression in bacteria growing in terrific broth. rRop2(196-561) was purified mainly as a soluble product and in high concentrations (approx 1 mg/mL) under native conditions (40 mM imidazol in phosphate buffer). However, after a cycle of freezing-thawing rRop2(196-561) became insoluble. When glycerol was added to 26%, immediately after purification, the protein stayed soluble after cycles of freezing-thawing. Finally, it was demonstrated that under these conditions soluble rRop2(196-561) keeps its diagnostic value in contrast with the insoluble protein.

Animals↗
PubMed2000

Expression of a cDNA encoding a Toxoplasma gondii protein belonging to the heat-shock 90 family and analysis of its antigenicity.

A cDNA clone (Tgzy85d11.r1) obtained from the Toxoplasma Expressed Sequence Tag project was chosen due to its homology with proteins of the heat shock 90 family. The cDNA encodes 137 amino acids of the C-terminal portion of the Toxoplasma Hsp90 protein (TgHsp90). Serum samples obtained from orally infected BALB/c and C57BL/6 mice showed reactivity against a recombinant TgHsp90 (rTgHsp90) after 8 weeks postinfection. Isotype analysis showed an anti-rTgHsp90 IgG2a/IgG3 response in infected BALB/c and anti-rTgHsp90 IgG1/IgG2a/IgG2b response in infected C57BL/6 mice. Serum samples from individuals chronically and putative acutely infected with T. gondii showed a similar anti-rTgHsp90 IgG response. Our work identifies TgHsp90 as a novel parasite antigen that seems to elicit a higher relation of anti-TgHsp90/anti-T. gondii IgGs during chronic infection in comparison with the acute stage.

Amino Acid Sequence↗
PubMed2000

Adjunctive therapy with oxcarbazepine in children with partial seizures. The Oxcarbazepine Pediatric Study Group.

OBJECTIVE: To evaluate the safety and efficacy of oxcarbazepine (OXC) as adjunctive therapy in children with inadequately controlled partial seizures on one or two concomitant antiepileptic drugs (AEDs). BACKGROUND: OXC has shown antiepileptic activity in several comparative monotherapy trials in newly diagnosed patients with epilepsy, and in a placebo-controlled monotherapy trial in hospitalized patients evaluated for epilepsy surgery. DESIGN: A total of 267 patients were evaluated in a multicenter, randomized, placebo-controlled trial consisting of three phases: 1) a 56-day baseline phase (patients maintained on their current AEDs); 2) a 112-day double-blind treatment phase (patients received either OXC 30-46 mg/kg/day orally or placebo); and 3) an open-label extension phase. Data are reported only from the double-blind treatment phase; the open-label extension phase is ongoing. METHODS: Children (3 to 17 years old) with inadequately controlled partial seizures (simple, complex, and partial seizures evolving to secondarily generalized seizures) were enrolled. RESULTS: Patients treated with OXC experienced a significantly greater median percent reduction from baseline in partial seizure frequency than patients treated with placebo (p = 0.0001; 35% versus 9%, respectively). Forty-one percent of patients treated with OXC experienced a > or =50% reduction from baseline in partial seizure frequency per 28 days compared with 22% of patients treated with placebo (p = 0.0005). Ninety-one percent of the group treated with OXC and 82% of the group treated with placebo reported > or =1 adverse event; vomiting, somnolence, dizziness, and nausea occurred more frequently (twofold or greater) in the group treated with OXC. CONCLUSION: OXC adjunctive therapy administered in a dose range of 6 to 51 mg/kg/day (median 31.4 mg/kg/day) is safe, effective, and well tolerated in children with partial seizures.

Adolescent↗
PubMed2000

Total oxidant scavenging capacity (TOSC) of microsomal and cytosolic fractions from Antarctic, Arctic and Mediterranean scallops: differentiation between three potent oxidants.

The enhanced formation of reactive oxygen species (ROS) is a common pathway of toxicity induced by stressful environmental conditions. In polar environments, characterization of antioxidant defences in key sentinel species may be of particular value as early detection biomarkers of unforeseen effects of human activities which are progressively increasing in these remote areas.The complexities associated with predicting the consequences at the 'organism level' of variations of specific antioxidant defences have been recently overcome by the ability to quantify an index of specific biological resistance to various kinds of ROS.The total oxyradical scavenging capacity (TOSC) assay has been used in three species of scallops for quantifying their ability to neutralize peroxyl (ROO(&z.rad;)) and hydroxyl (&z.rad;OH) radicals and peroxynitrite (HOONO). Adamussium colbecki and Chlamys islandicus represent key organisms for monitoring Antarctic and Arctic regions while Pecten jacobaeus was chosen for a comparison with a related temperate species. TOSC values for ROO&z.rad; were significantly higher in A. colbecki indicating this species as the most efficient scavenger of ROO&z.rad;. Mediterranean scallops had the lowest TOSC for ROO(&z.rad;). A. colbecki also exhibited the highest scavenging capacity for &z.rad;OH with values more than 2-fold greater than for C. islandicus and P. jacobaeus. TOSC for HOONO was lower for all scallops as compared to those for ROO&z.rad; or &z.rad;OH. TOSC for microsomes was not significantly different among the species for any ROS studied, and the percentage contribution to the specific TOSC for the various oxidants of microsomes of all scallops accounted for 1-3% of the total TOSC of the post-mitochondrial fraction. The specific TOSC of scallop microsomes for &z.rad;OH was approximately ten times lower than that for ROO&z.rad; or HOONO.The higher basal capability of the Antarctic scallop to neutralize different reactive oxygen species is discussed in terms of a possible adaptation to this extreme environment and TOSC is validated as a quantifiable measure of susceptibility to oxidative stress in marine organisms.

Journal Article↗
PubMed1999

Biomarker approach to evaluating the impact of scientific stations on the Antarctic environment using Trematomus bernacchii as a bioindicator organism.

A biomonitoring study was performed to evaluate the human impact on two small coves adjacent to the Italian Scientific Station at Terra Nova Bay in November 1995. The study used the fish species Trematomus bernacchii as a bioindicator organism for a biomarker analysis based on porphyrin levels, and BPMO (Benzo(a)pyrene MonoOxygenase) and EROD (Ethoxyresorufin-O-deethylase) activities. Porphyrin levels and EROD and BPMO activities were found to be generally low. In contrast to previous years, no statistically significant difference was found between the potentially contaminated cove and the control cove after the Italian expedition had been active nearby for a period of one month. This indicates a marked decrease in certain types of contaminants such as organochlorines and trace metals, mainly due to improvements in waste disposal.

Animals↗
PubMed1999

Progressive dystonia in a child with chromosome 18p deletion, treated with intrathecal baclofen.

We report a case of dystonia with a partial deletion of the short arm (p) of chromosome 18 and androgen insensitivity. Neurologic findings in the 18p syndrome are reported to include mental retardation, seizures, incoordination, tremor, and chorea. A 15-year-old girl with a denovo 18p deletion [karyotype 46, XY, del (18)(p11.1)] developed progressive asymmetric dystonia. She had oromotor apraxia and partial expressive aphasia since childhood, and she was able to partially communicate through elementary sign language. At the age of 15 years, she developed subacute and progressive choreic movements of the right arm, severe dystonic posturing of the left arm, and spastic dystonia in both legs. Her response to parenteral or oral benzodiazepines, oral trihexyphenidyl, benztropine mesylate, baclofen, and L-dopa were brief and inadequate. The response to intrathecal baclofen has been sustained over 18 months. In all likelihood, the 18p deletion syndrome affecting this patient is significant in the pathogenesis of her acquired dystonia. Chronic intrathecal baclofen therapy via pump has been effective in this case and should be considered as a treatment modality in carefully selected patients with dystonia.

Adolescent↗
PubMed1998

Diagnosis and treatment of prostatitis in Canada.

OBJECTIVES: There is a general consensus among physicians that the present management of chronic prostatitis is dismal. We undertook a survey of Canadian primary care physicians (PCPs) and urologists to determine the degree and source of frustration and to analyze present practice patterns in this disease. METHODS: Five thousand PCPs and all 545 Canadian urologists were asked to complete a comprehensive computer-assisted telephone survey that explored practice characteristics, attitudes, and diagnostic and treatment strategies in the management of prostatitis. Randomization of attribute banks, adherence to questionnaire routing, validation by on-site monitoring, and possible bias were addressed. RESULTS: Completed interviews were obtained from 10% of PCPs and 28% of urologists. PCPs see on average 3.5 (median 2) patients with prostatitis per month and urologists see on average 21.8 (median 11) patients with prostatitis per month. All physicians experience significantly more frustration in treating prostatitis than they do in treating patients with benign prostatic hyperplasia (BPH) and prostate cancer, and they perceive that prostatitis affects patients' quality of life significantly more than BPH and almost as much as prostate cancer. The degree of frustration and unhappiness in dealing with prostatitis is driven by a lack of confidence and comfort in their ability to accurately diagnose and subsequently rationalize treatment. Most PCPs and urologists continue to employ steps in addition to history and physical examination to establish a diagnosis but only a few PCPs and a third of urologists use specific lower urinary tract cultures. Physicians tend to use trimethoprim or trimethoprim-sulfamethoxazole (TMP-SMX) or a fluoroquinolone as their usual first line therapy for chronic prostatitis. The most commonly used therapeutic strategy (40%) for chronic prostatitis was TMP-SMX as first line therapy and a fluoroquinolone as second line therapy. CONCLUSIONS: There is widespread frustration, discomfort, and lack of confidence in both PCPs' and urologists' perceived ability to manage prostatitis. Physicians have expressed a desire for a better understanding of this disease, simpler and clearer diagnostic guidelines, and more rational treatment strategies.

Canada↗
PubMed1998

Exploring male fertility options after spinal cord injury: the role of the nurse clinician.

Male sexual function and fertility are important areas that need to be addressed for men undergoing spinal cord injury (SCI) rehabilitation. Rehabilitation nurses need to understand what fertility after SCI involves. Significant advances in the areas of sperm retrieval and advanced reproductive technologies have made biological parenthood for many men with SCI a viable option. This article reviews the various sperm retrieval techniques and advanced reproductive technologies available today. It also describes the unique role of a nurse clinician working in a fertility clinic designed specifically to address the fertility concerns of men and their partners after SCI.

Critical Pathways↗
PubMed1997

Screening for active toxoplasmosis in patients by DNA hybridization with the ABGTg7 probe in blood samples.

We report the potential use of a specific Toxoplasma gondii DNA probe (ABGTg7). We applied a dot blot hybridization assay to blood samples for the diagnosis of cerebral toxoplasmosis (CT), acute toxoplasmic lymphadenopathy (ATL), and disseminated toxoplasmosis in transplant recipients (TRs). We studied a total of 84 individuals: 38 patients and 46 controls. We found positive hybridization signals for 12 (66.7%) of 18 patients with confirmed CT, 9 (52.9%) of 17 patients with ATL, and 2 (66.7%) of 3 TRs. PCR assays were performed in parallel for patients with ATL, resulting in T. gondii DNA detection for 10 patients (58.8%). A comparative study between dot blot and PCR assays performed with the blood of mice that had been experimentally infected with tachyzoites gave similar results: 60 and 70% positive results, respectively. Finally, the sum of positive values obtained by both DNA tests (dot blot assay plus PCR) increased the rate of positivity for ATL patients to 76.4%. These results demonstrate that the T. gondii ABGTg7 repetitive DNA element is an additional useful resource for diagnosing Toxoplasma parasitemia in patients with CT and ATL and in TRs. Thus, our ABGTg7-based dot blot test may lead to an improvement in T. gondii detection methods in patients with acute toxoplasmosis.

Animals↗