Biomedical subjects
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Cognitive deficits are a key feature of schizophrenia. N-Methyl-D-aspartate (NMDA) receptor antagonists and amphetamine are known to induce psychotic behaviors and cognitive deficits in animals and humans, often affecting visuo-spatial abilities. Phencyclidine (PCP), MK-801 and amphetamine (AMPH) have been used in pharmacological animal models of schizophrenia, but none of these models has focused so far on spatial learning after repeated administration of the drugs. The objective of this study was to test whether repeated administration of PCP, AMPH or MK-801 influenced the performance of mice in a non-associative spatial learning test. CD-1 male mice were given i.p. daily injections of either saline, PCP (5.0, 10.0 mg/kg), AMPH (2.5, 5 mg/kg) or MK-801 (0.3, 0.6 mg/kg), for 5 days. On day 6 all mice were tested in an open field containing five different objects. After three sessions of habituation, each animal's reactivity to object displacement and object substitution was assessed. No significant differences among treatment groups were observed in object exploration or locomotion during the habituation phase. Five days of repeated PCP, AMPH or MK-801 administration selectively and differentially impaired the ability of mice to discriminate a spatial change, while leaving intact the ability to react to a non-spatial change. These data suggest that neurobiological adaptations to drug regimens known to induce psychotic behaviors and alterations in locomotor activity or stereotypies can also alter spatial learning, as assessed in this test, thus indicating that these regimens could also mimic some of the cognitive deficits observed in schizophrenia.
Electron number density and temperature were determined from laser-induced plasmas produced by irradiating Al-Cu-Fe targets of a quasicrystal and of an alloy of similar composition. The Al(I) atomic emission spectra of the two systems were measured as a function of the distance from the target and of the time delay after laser irradiation. Differences of plasma characteristics were observed for laser ablation of quasicrystal and alloy targets, and the results were interpreted on the basis of different plasma formation mechanisms for the two systems.
Pharmacological manipulation of both dopamine and glutamate systems affects motor responses in laboratory animals. The two systems, however, seem to act in opposite ways, since direct or indirect activation of dopamine receptors induces similar stimulatory effects to those seen following blockade of N-methyl-D-aspartate receptors. In the present study we compared the pattern of c-fos activation induced by systemic and intra-accumbens administration of the non-competitive N-methyl-D-aspartate antagonist MK-801 and the indirect dopamine agonist amphetamine. Systemic MK-801 induced c-fos mRNA expression in the motor cortex and preferentially in the motor thalamus, i.e. ventrolateral nucleus. Systemic amphetamine, on the other hand, enhanced c-fos mRNA expression in the shell of the accumbens and in limbic thalamic nuclei such as the anteroventral and anterodorsal nuclei. The main effect observed after intra-accumbens administrations of either drug was enhanced c-fos expression in the thalamus, somewhat similar to what seen following systemic administration. In fact also in this case there was a preferential activation of the limbic thalamus by amphetamine and the motor thalamus by MK-801. The present results confirm that different neural substrates underlie behavioral effects induced by systemic administrations of N-methyl-D-aspartate receptor antagonists and dopamine agonists. Further they suggest that intra-accumbens manipulation of the two neural systems could affect different efferent pathways from this structure activating different thalamic targets.
BACKGROUND: Patients with chronic hepatitis C infected by hepatitis A virus have a substantial risk of fulminant hepatitis or death, while the course of hepatitis A virus is uncomplicated in most subjects with chronic hepatitis B. AIM: To evaluate the prevalence of anti-hepatitis A virus antibodies and the incidence of hepatitis A virus seroconversion in a nationwide sample of 530 patients with chronic hepatitis B and/or hepatitis C infection initially susceptible to this infection after a follow-up of some years. RESULTS: The overall anti-hepatitis A virus prevalence was 85.7%, with no difference between males and females. By the age of 50 years, almost all patients were found to have been exposed to hepatitis A virus. After a mean follow-up period of 76 months the overall anti-hepatitis A virus seroconversion rate in the 76 initially susceptible individuals was 1.2 per 100 person/years. However, it was 0.3 per 100 person/years in those hepatitis B surface antigen positive but 3.36 per 100 person/years in those anti-hepatitis C virus positive. None of the seroconverters was affected by a clinically evident disease or showed deterioration of underlying chronic liver disease. CONCLUSIONS: The present study shows that Italian patients >50 years of age with chronic liver disease have already been exposed to hepatitis A virus suggesting that anti-hepatitis A virus screening is not advisable in these subjects.
Toxoplasma infection represents a rare but often fatal complication in bone marrow transplant (BMT) recipients. We report two cases of toxoplasmosis: one of successfully treated cerebral toxoplasmosis after peripheral blood stem cell transplantation, and a fatal case of pulmonary toxoplasmosis in a BMT recipient. We have systematically reviewed the 110 published cases of toxoplasmosis following BMT. We analyzed the pre-transplant and clinical features of BMT recipients developing toxoplasmosis, together with the diagnostic procedures used and treatment given. By univariate and multivariate statistical analysis we analyzed the risk factors for diagnosis (during life vs post-mortem) and Toxoplasma-related mortality. Ante-mortem diagnosis was made in 47% of cases. Site of infection (P = 0.02; odds ratio 10.8), presence of symptoms at onset (P = 0.01) and conditioning regimen (P = 0.04) were factors influencing whether the diagnosis was made before or after death. Overall mortality rate was 80% and that attributed to toxoplasmosis was 66%. Variables influencing outcome were: site of infection (P = 0.02; odds ratio 5.28), day of onset (P = 0.04) and conditioning regimen (P = 0.04). Underlying disease (P = 0.02; odds ratio 9.45), among patients diagnosed before death, was the most significant factor influencing outcome.
We conducted a retrospective cohort study to estimate the incidence of major blood-borne agents among Italian blood donors and calculated the risk of infection among blood recipients using the 'incidence/window period model'. The study was conducted among 46 180 blood donors enrolled in six blood centres between 1994 and 1999. During follow-up, seven new infections were confirmed: three donors seroconverted for anti-human immunodeficiency virus (HIV); two for anti-hepatitis C virus (HCV); and two showed hepatitis B surface antigen (HBsAg) reactivity; no cases of syphilis were observed. The incidence rates per 100 000 person/years were: 4.06 (95% CI: 0.82-11.85) for HIV; 2.41 (95% CI: 0.29-8.70) for HCV; and 2.70 (95% CI: 0.32-9.77) for HBsAg; the incidence for total hepatitis B virus (HBV) infection was 9.77 per 100 000 person/years (95% CI: 1.16-35.36). The estimated risk of an infectious blood unit not being detected was: 2.45 (95% CI: 0.13-12.33) per 1 million units for HIV; 4.35 (95% CI: 0.30-22.39) for HCV; and 15.78 (95% CI: 1.16-84.23) for HBV. Overall, an estimated 22.58 per 1 million units are infected. In Italy, the risk of transfusion-transmitted infections is low and is similar to that in other western countries. The introduction of new more sensitive screening tests could reduce the residual risk of transfusion-transmitted infection by 40-80%.
Travel to endemic areas is one of the most frequently reported risk factors for infection with the hepatitis A virus (HAV). We evaluated the association between HAV infection and travel, by area of destination. We conducted a case-control study on all cases of HAV infection reported to the Italian National Surveillance System for Acute Viral Hepatitis in the period 1996-2000. The study population consisted of 9695 persons with HAV infection (cases) and 2590 with HBV infection (controls). The risk of acquiring HAV was highest for travel to Asia, Africa and Latin America [Odds Ratio = 9.30 (95%CI = 6.71-12.9)]; a three-fold statistically significant excess of risk was found for travel to southern Italy (OR = 3.03) and to the Mediterranean Area and Eastern Europe (OR = 3.15). Travel was implicated in 28% of the cases of HAV infection. When stratifying the analysis by area of residence (northern and central Italy vs southern Italy and the Islands), the above-mentioned risks were confirmed only for those residing in northern and central Italy, with no significant risk for those residing in southern Italy and the Islands. Travel to areas endemic for HAV infection constitutes a considerable risk. Our results highlight the importance of developing health policies for improving environmental and hygienic conditions, as well as the prevention of certain eating habits. Vaccination before travelling to a medium or high endemic area could be a safe and effective means of preventing travel-related HAV infection.
Gemcitabine is a pyrimidine nucleoside analog with antitumor activity against solid tumor malignancies and leukemia. We evaluated its activity as a single agent and combining it with cisplatin in relapsed-refractory multiple myeloma (MM). Sixteen patients with advanced MM received intravenous gemcitabine 1250 mg/mq (days 1, 8 and 15) as a single agent for a total of 3 monthly courses. The responders received another three courses, and the non-responders received three courses of gemcitabine 1000 mg/mq (days 1, 8 and 15) plus cisplatin 80 mg/mq (day 1). No grade 4 hematological toxicity was seen after gemcitabine treatment, whereas > or = 3 grade neutropenia and thrombocytopenia were seen in 21 and 13% of the gemcitabine-cisplatin infusions, respectively. Non-hematological toxicity was negligible for both the regimens. After three courses of gemcitabine as a single agent, th e response rate was 31% (1 complete response, 1 partial response and 3 minimal response). Eight patients (50%) achieved stable disease and 3 (19%) had disease progression. Ten patients received gemcitabine-cisplatin and were evaluable for the response. Two patients progressed, four maintained stable disease whereas four patients, unresponsive to gemcitabine, obtained a response (3 partial response and 1 minimal response). With a median follow-up of 13 months (range 8-17.5), 7 patients (44%) died, 5 (31%) had disease progression, 1 (6%) relapsed, 1 was still in partial response (+11 months) and 2 (13%) had a stable disease. Median time to treatment failure (TTF) was 8 months (CI95%: 7.6-8.4) and median overall survival (OS) was 16 months (CI95%: 10-22). These results showed that gemcitabine and gemcitabine-cisplatin were feasible regimens and well tolerated in advanced relapsed-refractory MM. The response rates, the TTF and OS were similar to other salvage chemotherapy regimens; nevertheless, the quality of response was modest particularly after gemcitabine alone. Better results might be obtained combining gemcitabine with other chemotherapy compounds or with biologically based therapies.
BACKGROUND: Hepatitis C virus (HCV) infection is common worldwide but there are different prevalence rates in different countries. Data on the incidence of HCV in the general population are scarce. Spontaneous viral clearance occurs in 10-25% of infected individuals after acute infection yet controversy exists regarding the frequency of spontaneous clearance during the natural course of HCV infection in the general population. AIMS: Anti-HCV prevalence, HCV infection rate, and the kinetics of anti-HCV were studied in a cross section of the general population of central Italy. STUDY POPULATION AND METHODS: Anti-HCV prevalence (EIA-3 Ortho, RIBA-3 Ortho Chiron) was estimated in 3884 randomly selected individuals. Infection rate and antibody kinetics were estimated in 2032 participants for whom a second blood sample was taken after a median follow up of seven years. HCV-RNA determination by polymerase chain reaction was performed on follow up sera. RESULTS: The overall confirmed anti-HCV prevalence was 2.4%. Two participants seroconverted for anti-HCV, giving an overall infection rate of 1.4 cases per 10 000 person years (95% confidence interval 0.2-5.2 per 10 000 person years). Of the 36 individuals confirmed as anti-HCV positive at enrollment, seven (19.4%) showed complete seroreversion. Seven (87%) of the eight individuals with indeterminate results at enrollment were serologically non-reactive at the end of follow up. Of the 25 participants confirmed to be anti-HCV positive at both enrollment and follow up, 23 (92.0%) with stable serological profiles tested positive for HCV-RNA at the end of follow up. CONCLUSIONS: There is still a permanent risk, although low, of HCV spread in the general population in an area of low level endemicity. In this setting, a wide spectrum of modifications of viral and antibody patterns can be observed in HCV infected patients.
This study examined 522 children born to hepatitis B surface antigen (HBsAg)-positive mothers from 1985 through 1994 and evaluated the protection provided by anti-hepatitis B virus (HBV) immunization at birth. Babies were given hepatitis B immunoglobulin and hepatitis B vaccine at birth. At 5-14 years after immunization, 17 children (3.3%) were anti-HB core antigen positive, and 3 also were HBsAg positive. One carrier child had a double mutation, with substitution of proline-->serine at codons 120 (P120S) and 127 (P127S) within the a determinant of HBsAg. Of the 522 children, 400 (79.2%) of 505 still had protective anti-HBsAg titers > or =10 mIU/mL. Thus, HBV vaccination of children born to HBsAg-positive mothers is effective and confers long-term immunity. There is no evidence that the emergence of HBV escape mutants secondary to the immune pressure against wild-type HBV is of concern.
Varicella-zoster virus (VZV) frequently causes severe infections in patients who have undergone bone marrow transplantation. The frequency of, characteristics of, and risk factors for this infection were studied in 164 patients undergoing autologous peripheral blood progenitor cell transplantation (PBPCT). Twenty-six patients (15.8%) developed VZV infection, and the actuarial risk was 10% at 1 year. No patient had visceral dissemination or died because of VZV, although one-third of the patients developed postherpetic neuralgia. By multivariate analysis, a CD4(+) lymphocyte count of <200 cells/microL (P<.0001; odds ratio [OR], 2.0) and a CD8(+) lymphocyte count of <800 cells/microL (P=.0073; OR, 2.0) at day 30 after transplantation were factors associated with VZV infection. Patients with both these adverse factors had an actuarial risk of VZV of 48% at 1 year. Patients with deficiency in both CD4(+) and CD8(+) lymphocytes are at high risk of VZV infection. These patients should be considered as candidates for preventive therapy, but whether for antiviral therapy or vaccination remains to be investigated.
In Italy, improved sanitation and living conditions have led to a decline in the rate of hepatitis A infection among children generating an increasing proportion of adults susceptible to this virus. Shellfish consumption is a major source of infection while person to person transmission is important in the spread of infection and in the maintenance of outbreaks. Thus prevention of secondary HAV infection is a crucial point. A randomised controlled trial of hepatitis A vaccine in household contacts of people with sporadic HAV infection in Italy has shown a protective efficacy of 82% (CI 20-96%). The two secondary infections in the vaccine group were symptomless, suggesting that the disease expression may be weaker in vaccinated subjects.
Most of the research on ventral striatal functions has been focused on their role in modulating reward and motivation. More recently, a possible role of this structure in cognitive functions has been suggested. However, very little information is available on the involvement of the nucleus accumbens in the different stages of the consolidation process. In this study, the effect of focal injections of AP-5 and DNQX, competitive antagonists at the NMDA and AMPA receptors, respectively, was examined in a nonassociative task designed to estimate the ability of mice to react to spatial changes. The task consists of placing the animals in an open field containing five objects; after three sessions of habituation, their reactivity to object displacement was examined 24 hr later. AP-5 injections administered after training impaired the ability of mice to detect the spatial novelty but did not affect response when injected 120 min after training or before testing. On the contrary, DNQX did not affect response when administered immediately or 120 min after training but did impair spatial discrimination when administered before training or testing. These data demonstrate a double dissociation between glutamate receptor subtypes, such that accumbens NMDA receptors are important for consolidation and not ongoing discrimination of spatial information, whereas AMPA receptors have an opposite role in these processes.
Ionspray (IS) and fast atom bombardment (FAB) positive ionization mass spectrometry (MS) of 1 : 1 beta-cyclodextrin (beta-CD)-melatonin (MLT) host-guest complex allowed the detection of gaseous protonated 1 : 1 beta-CD-MLT. Tandem MS collision-induced dissociation (CID) of such protonated 1 : 1 beta-CD-MLT species showed the proton (charge) to be retained to a significant extent by the host and by its cage fragmentation products, in spite of the higher proton affinity of MLT with respect to that of beta-CD. This requires an endothermic guest-to-host proton transfer to occur within the gaseous association. Collisional activation could be accounted for by the promotion of such an endothermic process; however, the proton affinity decrease of the guest determined by the loss of the elements of acetamide, which is a dominant MS dissociation reaction of pure protonated MLT, could also provide a rationale for such an endothermic guest-to-host proton transfer. This proposal parallels the reaction scheme we had previously formulated for the analogous MS and tandem MS behaviour of 1 : 1 beta-CD-5-methoxytryptamine inclusion complex with the protonated 5-methoxytryptamine guest undergoing deamination.
BACKGROUND/AIMS: To evaluate the strength of association between parenterally transmitted viral hepatitis and specific types of invasive procedures. METHODS: Data from the surveillance system for type-specific acute viral hepatitis (SEIEVA) during the period 1994-1999 were used. The association of acute hepatitis B virus (HBV) and hepatitis C virus (HCV) infection with the potential risk factors (odds ratios (OR)) was estimated comparing 3120 hepatitis B and 1023 hepatitis C cases with 7158 hepatitis A cases, used as controls, by multiple logistic regression analysis. RESULTS: Most procedures resulted in being associated with the risk of acquiring acute HBV or HCV. The strongest associations were: for HBV infection, abdominal surgery (adjusted OR = 3.9; 95% confidence intervals (CI) = 2.0-7.5), oral surgery (OR = 2.7; 95% CI = 1.6-4.5) and gynaecological surgery (OR = 2.6; 95% CI = 1.2-5.5); for HCV infection, obstetric/gynaecological interventions (OR = 12.1; 95% CI = 5.6-26.3), abdominal surgery (OR = 7.0; 95% CI = 3.2-14.9) and ophthalmological surgery (OR = 5.2; 95% CI = 1.1-23.2). Biopsy and/or endoscopy were associated with HCV, but not with HBV infection. CONCLUSIONS: Invasive procedures represent an important mode of HBV and HCV transmission. Since a large proportion of the adult general population is exposed to these procedures and an effective HCV vaccine is not yet available, non-immunological means of controlling iatrogenic modes of transmission are extremely important.
To assess hepatitis C virus (HCV) incidence rates and identify determinants of infection among hemodialysis patients, a multicenter study was conducted in 58 units in ITALY: An initial seroprevalence survey was conducted among 3,492 patients already on hemodialysis therapy as of January 1997 and among an additional 434 patients who began dialysis up to January 1998. HCV antibodies were assessed by third-generation enzyme immunoassays. Patients testing seronegative at baseline were enrolled into a 1-year incidence study with serological follow-up at 6 and 12 months. For patients who seroconverted, an HCV RNA assay was performed on stored baseline samples to confirm new infection. A nested case-control study was subsequently performed to investigate potential risk factors. For each incident case, three controls negative for both HCV antibodies and HCV RNA were randomly selected. At enrollment, HCV seroprevalence was 30.0%. During follow-up, 23 new HCV cases were documented, with a cumulative incidence of 9.5 cases/1,000 patient-years. By logistic regression analysis, an increased risk for HCV infection emerged for patients attending the dialysis units with a high prevalence of HCV-infected patients at baseline (odds ratio [OR], 4.6) and for those attending units with a low personnel-patient ratio (OR, 5.4). Among extradialysis factors, a history of surgical intervention in the previous 6 months (OR, 16.7) significantly increased HCV risk. These findings suggest that the combination of understaffing and a high level of infected patients in the dialysis setting increases the risk for HCV nosocomial transmission. This is likely related to an increased likelihood for breaks in infection control measures.
We have recently shown that focal administration of dizocilpine hydrogen maleate (MK-801, a non-competitive N-methyl-D-aspartate antagonist) within the nucleus accumbens increases locomotor activity in a dopamine-independent manner. The purpose of this study was to investigate the neural network underlying locomotor stimulation induced by N-methyl-D-aspartate receptor blockade in the accumbens. In the first experiment, we examined the effect of different doses (1, 5 and 25 nmol) of the active and inactive enantiomers of the N-methyl-D-aspartate antagonist, (+)- and (-)-MK-801, respectively, focally administered in the nucleus accumbens. Only the active enantiomer induced a significant increase in locomotor activity; furthermore, the effect induced by the two highest doses of (+)-MK-801 was significantly different from that induced by (-)-MK-801. In the second part of the study, we performed ibotenic acid lesions to the major output nuclei of the accumbens, the ventral pallidum, mediodorsal thalamus, ventrolateral/ventromedial thalamus and pedunculopontine tegmental nucleus, to observe their effect on locomotor activity induced by focal (+)-MK-801 (25 nmol) administration into the accumbens. None of the lesions had any effect on spontaneous locomotor activity. Hyperactivity induced by accumbens MK-801 administrations was unaffected by ibotenic acid lesions of the pedunculopontine tegmental nucleus, while lesions of the mediodorsal thalamus induced only a partial inhibition. In contrast, ibotenic acid lesions of the ventral pallidum and ventrolateral/ventromedial thalamus completely blocked the motor response induced by accumbens MK-801. These data indicate that the intact mediodorsal thalamus, which has been proposed as a part of the loop that relays accumbens information to the prefrontal cortex, does not seem to be a structure of primary importance in MK-801 locomotor activity. On the contrary, the motor nuclei of the thalamus appear to play a more relevant role, suggesting that different neural substrates may mediate dopamine and glutamate functional output from the nucleus accumbens.