Biomedical subjects
Publications and source records attributed to M Catalano.
We show how the electronic states of quantum wires and quantum dots can be evaluated exactly starting from the profile of the nanostructure observed by transmission electron microscopy, scanning tunneling microscopy and atomic force microscopy. The calculated quantization energies reproduce the energy position of the luminescence resonances in the optical spectra of different samples, without fitting parameters.
Nanostructured semiconductor particles are currently under intense investigation because of their enhanced photoreactivity and photocatalytic properties due to the quantum-size effect and the dependence of the photophysical and photochemical properties on their size as it approaches the exciton diameter. This increasing interest has led to the development of several synthetic procedures to prepare and stabilise uniform crystallites. In this paper, we report a novel synthetic pathway to obtain cadmium sulphide (CdS) nanoparticles in a quaternary "water-in-oil" microemulsion formed by a cationic surfactant cetyltrimethylammonium bromide (CTAB), pentanol, n-hexane and water. The synthesis of CdS in this system is achieved by mixing two microemulsions containing Cd(NO3)2 and Na2S, respectively. The nanocrystals have been characterised by using UV--visible spectroscopy and Transmission Electron Microscopy to investigate the influence of various parameters of the particles' formation and stability in solution. Capping of nanoparticles with suitable organic molecules has been performed in order to increase their stability and afford solubility in a wide range of solvents.
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Staphylococcus aureus is an important cause of bovine mastitis worldwide, and effective preventive or therapeutic modalities are lacking. Although most human S. aureus isolates produce capsular polysaccharides (CPs), few reports have described the prevalence of capsules on bovine isolates. This information is important for the rational design of a vaccine for the prevention of staphylococcal mastitis. We serotyped 195 S. aureus strains isolated between 1989 and 1997 from the milk of mastitic cows in Argentina. Only 14 (7.1%) of the strains were serotype 5, and all were recovered between 1989 and 1992. Thirteen serotype 8 strains were identified, and 12 of these were isolated between 1991 and 1994. The remaining 168 isolates were nonreactive (NR) with CP serotype 5 (CP5)- or CP8-specific antibodies. Hybridization studies performed with genomic DNA from eight NR strains revealed that only three of them carried the capsule genes. Pulsed-field gel electrophoresis (PFGE) performed with 127 of the 195 S. aureus isolates revealed that most (86%) strains belonged to one of four major PFGE groups. Although 8 of 14 CP5 isolates showed a common PFGE pattern (arbitrarily defined as A1), 31 other A1 isolates from the same time period (1989 to 1992) were not CP5 positive. In contrast, only nine PFGE type B3 isolates were recovered between 1990 and 1994, and eight of these were positive for CP8 (P < 0.0003). The results of this study underscore the variability in capsule expression by S. aureus strains isolated from different geographical regions and cast doubt on the roles of CP5 and CP8 in the pathogenesis and immunoprophylaxis of bovine mastitis in Argentina.
Recurrent panic attacks, anticipatory anxiety and phobic avoidance characterise panic disorder. The influence of genetic factors on liability to the disease has been the object of several linkage and association studies and appears to relate to an oligo- or polygenic rather than a monogenic mode of inheritance. Recently, an excess of high activity monoamine oxidase A (MAO-A) gene promoter alleles was found in female patients with panic disorder. An analysis of possible synergistic effects of the MAO-A gene promoter variant and the short serotonin transporter (5-HTT) gene promoter variant in panic disorder was performed in a German and an Italian sample (combined panic disorder n = 144, combined controls n = 175). There was no significant difference in odds ratios, suggesting that the observed increase of genetic liability by the long MAO-A gene promoter allele is not modified by the 5-HTT gene promoter polymorphism.
Previously, we reported an association of the dopamine receptor D4 (DRD4) gene with delusional symptomatology of major psychoses. However, DRD4 variants accounted for only 2% of the phenotypic variance, indicating that contributions from other genes were probable. The serotonin transporter gene is a primary candidate in major psychoses, and a functional polymorphism in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) has recently been reported to be associated with a number of psychopathological conditions. In the present study we investigated the original cohort of subjects to evaluate the 5-HTTLPR possible influence on the psychopathology of major psychoses in interaction with DRD4. Four hundred and sixty-one inpatients affected by major psychoses were assessed by the Operational Criteria Checklist for Psychotic Illness (OPCRIT) and were also typed for the 5-HTTLPR and DRD4 variants using polymerase chain reaction techniques. Mania, depression, delusion, and disorganization were the four symptomatologic factors used as phenotype definition. 5-HTTLPR variants did not significantly influence the previously reported association of DRD4 with delusional symptoms. No interaction was observed on the other symptom factors. The serotonin transporter gene does not, therefore, interact with DRD4 in determining the symptomatology of major psychoses.
We previously reported an association between dopamine receptor D4 (DRD4) gene exon 1 variants and delusional disorder. The aim of this investigation was to study the DRD4 gene exon 1 and 3 variants in schizophrenia, delusional, bipolar, and unipolar disorders. We studied 651 inpatients affected by schizophrenia (n = 229), delusional (n = 86), bipolar (n = 210), and unipolar (n = 126) disorders (DSM III-R) and 471 healthy controls; these were typed for DRD4 variants at the first and third exon using polymerase chain reaction techniques. DRD4 variants were not associated with schizophrenic and delusional subjects even when possible confounders like gender and onset were considered. A marginal association between DRD4 exon 3 variants with unipolar (excess of DRD4*2/4, p = 0.004) and bipolar (excess of DRD4*2/4, p = 0.001) disorders was observed, both associations drop to insignificance when corrected for multiple testing. Our results exclude that coding variants of the DRD4 exon 1 and 3 may play a major role in conferring susceptibility to major psychoses; moreover, we could not replicate the association of DRD4 exon 1 variant with delusional disorder.
Lasing action has been demonstrated at blue wavelengths in vertical cavity surface-emitting lasers at room temperature. The microcavity was formed by sandwiching indium gallium nitride multiple quantum wells between nitride-based and oxide-based quarter-wave reflectors. Lasing action was observed at a wavelength of 399 nanometers under optical excitation and confirmed by a narrowing of the linewidth in the emission spectra from 0.8 nanometer below threshold to less than 0.1 nanometer (resolution limit) above threshold. The result suggests that practical blue vertical cavity surface-emitting lasers can be realized in gallium-nitride-based material systems.
Lithium is an effective prophylactic agent in mood disorders, and genetic factors are likely to modulate individual susceptibility to lithium treatment. The aim of this study is to investigate the influence of dopamine receptor D2 (DRD2), D4 exon 3 (DRD4), and gamma-aminobutyric acid type A (GABA(A)) receptor alpha-1 subunit (GABRA1) gene variants on the efficacy of lithium prophylaxis in mood disorders. Patients with mood disorders (N = 125: bipolar subtype, n = 100; major depressive disorder subtype, n = 25) were followed prospectively for an average of 53 months and were typed for DRD2 (Ser311/Cys311: n = 121, VNTR: n = 63), DRD4 (n = 125) and GABRA1 (n = 61) variants using polymerase chain reaction (PCR) techniques. DRD2, DRD4 and GABRA1 variants were not associated with response to lithium. A trend was observed toward a better outcome of DRD4* 2/4 subjects, but it was due to only two subjects. Consideration of possible stratification effects like gender, polarity, family history, age at onset and duration of lithium treatment did not reveal any association either. DRD2, DRD4 and GABRA1 variants therefore do not appear to be associated with the outcome of lithium prophylaxis in mood disorders.
A functional polymorphism in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) has been recently reported to be associated with mood disorders. In the present study we investigated the possible influence of 5-HTTLPR on the symptomatology of mood disorders. Two hundred and thirty inpatients affected by mood disorders (160 bipolar and 70 major depressive disorder) were assessed by the Operational Criteria checklist for psychotic illness (OPCRIT) and were also typed for the 5-HTTLPR variants using PCR techniques. Mania, Depression, Delusion and Disorganization were the four symptomatologic factors used as phenotype definition. 5-HTTLPR variants were not associated with these symptomatologic factors, and consideration of possible stratification effects, such as sex, age of onset and polarity, did not reveal any association either. The serotonin transporter gene does not, therefore, appear to be associated with the symptomatology of mood disorders.
Previously, we reported on an association of the dopamine receptor D4 (DRD4) gene with delusional symptomatology of major psychoses. However, despite the strength of the association, it only accounted for 2% of the variance, indicating that contributions from other genes were probable. In the present study, we investigated the original cohort of subjects to evaluate the gene for the gamma-aminobutyric acid type A (GABA(A)) receptor alpha-1 subunit (GABRA1). The possible association of GABRA1 with the psychopathology of major psychoses was tested both alone and in interaction with DRD4. Four hundred and sixty-one inpatients affected by major psychoses were assessed by the operational criteria checklist for psychotic illness (OPCRIT) and were also typed for the DRD4 and GABRA1 variants using PCR techniques. Mania, depression, delusion, and disorganization were the four symptomatologic factors used as phenotype definitions. GABRA1 variants were not associated with these symptomatologic factors, and consideration of possible stratification effects such as sex and psychiatric diagnosis also did not reveal any association. GABRA1 variants did not significantly influence the association of DRD4 with delusional symptoms. No interaction was observed on the other symptom factors. The GABA(A) alpha-1 subunit gene does not, therefore, interact with DRD4 in the symptomatology of major psychoses.
The serotonin transporter gene is a primary candidate for involvement in major psychoses. A functional polymorphism in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) has recently been reported to be associated with a variety of psychopathological conditions. In the present study, we investigated the potential influence of the 5-HTTLPR on the psychopathology of schizophrenia. One hundred and sixty-one inpatients affected by schizophrenia (DSMIII-R) were assessed by the Operational Criteria checklist for psychotic illness (OPCRIT) and were typed for their 5-HTTLPR variants by PCR techniques. Mania, Depression, Delusion and Disorganization were the four symptomatologic factors used to define phenotype. 5-HTTLPR variants were not associated with these symptomatologic factors, and consideration of possible stratification effects such as sex, and age of onset did not reveal any association either. The serotonin transporter gene is not a liability factor for the symptomatology of schizophrenia.
Disturbances of the serotoninergic neutrotransmitter system have been implicated in the pathogenesis of mood disorders. A functional polymorphism in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) has been recently reported to be associated with both unipolar and bipolar disorder. In this study, we investigated the possibility that the 5-HTTLPR might be associated with depressive symptomatology in a sample of mood disorder subjects. One hundred and thirty-two psychiatric inpatients affected by major depressive (n = 67) and bipolar (n = 65) disorder (DSM-IV) were assessed at admission by the Hamilton Depression Rating Scale (HAMD-21, divided into Core, Sleep, Activity, Psychic anxiety, Somatic anxiety and Delusion clusters) and were typed using PCR techniques. The only prior treatment permitted was low dose benzodiazepines (<5 mg diazepam or equivalent); no prior (<2 weeks) antidepressant or neuroleptic treatment was allowed. 5-HTTLPR variants were not associated with total depressive symptomatology as measured by HAMD. The short 5-HTTLPR variant was marginally associated with higher psychic anxiety scores (F = 7.11, d.f. = 1,262, P = 0.008). The association was stronger among bipolars and early onset subjects. 5-HTTLPR variants were not associated with the remaining symptom clusters. The upstream regulatory region of the serotonin transporter gene has not, therefore, a major influence on the depressive symptomatology in mood disorder subjects.
BACKGROUND: Large pedunculated colorectal polyps are often difficult to remove endoscopically. METHODS: Four patients with giant pedunculated polyps (>3 cm) underwent an endoscopic procedure in which the polyp stalk was ligated with multiple clips and resected with a needle-knife papillotome. RESULTS: No complications occurred either during or immediately after the procedure. Mean size of the resected polyps was 4.8 +/- 1.2 cm (range 3 to 6 cm). Mean time for the entire procedure was 31 +/- 5 minutes (range 25 to 45). No bleeding was found after a mean follow-up period of 4.3 +/- 1.1 months (range 3 to 6 months). CONCLUSIONS: Although technical refinements are necessary to make the procedure easier and faster, this approach might represent the only option for selected patients who would otherwise need surgical resection of large pedunculated colonic polyps.
Genotypic methods showed Acinetobacter baumannii biotype 9 genotype I to be the epidemic strain on an outbreak in an intensive care unit (ICU) which lasted from January to April of 1996. A cohort was established during March in which hospital personnel were assigned exclusively to A. baumannii infected or colonized patients. New patients were not admitted to the ICU until the last infected patient was discharged. However, strain I was isolated during April and vectors other than human carriage were suspected. The ICU comprised four sections; patients and beds were moved within them according the severity of diseases. Strain I was isolated from a bed rail nine days after the infected patient was discharged. This dry vector may explain the transmission of the epidemic strain between sections. The following July, four new infected patients were identified and three different strains, including the epidemic one, were recovered. The two other strains were also isolated from a bed rail. Although this environmental source does not explain by itself the transmission of an epidemic strain, it illustrates that dry vectors can be secondary reservoirs where A. baumannii can survive.
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A genetic contribution to the pathogenesis of panic disorder has been demonstrated by clinical genetic studies. Molecular genetic studies have focused on candidate genes suggested by the molecular mechanisms implied in the action of drugs utilized for therapy or in challenge tests. One class of drugs effective in the treatment of panic disorder is represented by monoamine oxidase A inhibitors. Therefore, the monoamine oxidase A gene on chromosome X is a prime candidate gene. In the present study we investigated a novel repeat polymorphism in the promoter of the monoamine oxidase A gene for association with panic disorder in two independent samples (German sample, n = 80; Italian sample, n = 129). Two alleles (3 and 4 repeats) were most common and constituted >97% of the observed alleles. Functional characterization in a luciferase assay demonstrated that the longer alleles (3a, 4 and 5) were more active than allele 3. Among females of both the German and the Italian samples of panic disorder patients (combined, n = 209) the longer alleles (3a, 4 and 5) were significantly more frequent than among females of the corresponding control samples (combined, n = 190, chi2 = 10.27, df = 1, P = 0.001). Together with the observation that inhibition of monoamine oxidase A is clinically effective in the treatment of panic disorder these findings suggest that increased monoamine oxidase A activity is a risk factor for panic disorder in female patients.