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M Nebuloni

Publications and source records attributed to M Nebuloni.

At least 37 records · Page 2Linked to original sources
PubMed1998

Nested polymerase chain reaction for Mycobacterium tuberculosis IS6110 sequence on formalin-fixed paraffin-embedded tissues with granulomatous diseases for rapid diagnosis of tuberculosis.

We evaluated the sensitivity and specificity of a nested polymerase chain reaction (PCR) to the Mycobacterium tuberculosis IS6110 sequence on formalin-fixed paraffin-embedded tissue samples from patients with tubercular and other granulomatous lesions. Five groups of patients and samples were studied: (1) 28 samples from HIV-positive patients with tuberculosis, (2) 8 samples from HIV-negative patients with histologically suspected tuberculosis (confirmed by culture in 5 cases), (3) lymph nodes from 5 HIV-positive patients with Mycobacterium avium-intracellulare infection, (4) lymph nodes from 30 patients with sarcoidosis, and (5) specimens from 17 patients with other granulomatous diseases. The DNA was extracted from sections with a total thickness of 60 microm, and PCR amplified an internal fragment of 123 base pairs. All of the cases with M. tuberculosis infection were PCR-positive, although this sensitivity was partially related to the initial concentration of the DNA used for amplification. Two of the group 4 samples also were repeatedly positive, thus reducing the specificity of the method. All of the cases with granulomatous diseases other than sarcoidosis were negative. We propose a simplified and highly sensitive nested PCR for the diagnosis of M. tuberculosis infection on archived material in HIV-positive and HIV-negative patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Evaluation of PCR in detection of Mycobacterium tuberculosis from formalin-fixed, paraffin-embedded tissues: comparison of four amplification assays.

We compared the sensitivities and specificities of four nested PCR assays for the detection of Mycobacterium tuberculosis from formalin-fixed, paraffin-embedded tissues. Thirty-seven autopsy samples from human immunodeficiency virus-positive patients were analyzed: 15 were M. tuberculosis positive, 11 served as negative controls, and 11 were Ziehl-Neelsen positive without cultural confirmation of M. tuberculosis. Three genomic sequences (mtp40, 65-kDa antigen gene, and IS6110) with different molecular masses and numbers of repetitions within the M. tuberculosis genome were targeted. On the IS6110 sequence, two fragments of different sizes (106 and 123 bp, respectively) were amplified with two separate pairs of primers. The highest sensitivity rates were obtained by amplifying the highly repetitive IS6110 insertion sequence, and the different primers tested showed a sensitivity ranging from 80 to 87%. Amplification of the large 223-bp fragment of the mtp40 sequence present in a single copy in the M. tuberculosis genome yielded a high rate of false-negative results, ranging from 66 to 80%. A poor sensitivity (from 47 to 60%) was also shown by PCR amplification of the 142-bp 65-kDa antigen gene. All the PCRs except that for the 65-kDa antigen gene showed a specificity of 100%. Moreover, different results were obtained with different dilutions of DNA, and DNA concentrations of 1 and 3 microg yielded the highest sensitivities depending upon which protocol was used. Application of the PCRs to the Ziehl-Neelsen-positive, culture-negative samples confirmed the sensitivities of the PCRs obtained with the control samples. In conclusion, PCR can successfully be used to detect M. tuberculosis from paraffin-embedded tissues and can be particularly useful in the validation of a diagnosis of tuberculosis in clinical settings in which the diagnosis is uncertain. However, the efficacy of PCR strictly depends on several amplification parameters such as DNA concentration, target DNA size, and the repetitiveness of the amplified sequence.

Evaluation Studies as Topic↗
PubMed1998

VZV fulminant necrotizing encephalitis with concomitant EBV-related lymphoma and CMV ventriculitis: report of an AIDS case.

A case of AIDS with varicella zoster virus fulminant necrotizing encephalitis associated with cytomegalovirus ependymitis-subependymitis and a periventricular Epstein-Barr virus-related lymphoma is described. The patient had no herpes zoster cutaneous eruptions and died three days after the onset of symptoms. Varicella zoster virus and cytomegalovirus antigens were found by immunohistochemistry in the same area around a necrotic periventricular lesion; a periventricular lymphoma, large B cell type, was also observed. In situ hybridization with Epstein-Barr virus-encoded- RNAs probe was positive in about 40% of the neoplastic cells. The association of herpes-related lesions in the same cerebral region should be consistent in AIDS cases with acute neurological symptoms.

AIDS-Related Opportunistic Infections↗
PubMed1997

Predictors of cytomegalovirus disease, natural history and autopsy findings in a cohort of patients with AIDS.

OBJECTIVE: To identify the predictors of acquiring cytomegalovirus (CMV) disease, and to describe natural history, therapeutic management and autopsy findings in affected patients. DESIGN: Observational study of a consecutive cohort of AIDS patient diagnosed and followed in the same institution. METHODS: All of the patients with CMV were included. Statistical analyses were performed to establish the risk of acquiring the disease at or after AIDS presentation, survival, and the occurrence and time of relapses in relation to maintenance therapy. The presence of CMV infection at autopsy was also investigated. RESULTS: CMV disease was diagnosed in 304 (24.8%) out of 1,227 patients, its incidence increasing according to the year of AIDS diagnosis. Women, homosexual men, patients given zidovudine and Pneumocystis carinii pneumonia (PCP) prophylaxis before AIDS, and severely immunodepressed patients were at higher risk for the disease. CMV disease was an independent factor of worse survival (hazard ratio, 1.7 versus PCP; 95% confidence intervals, 1.28-2.13). Patients untreated during the acute phase had a 4.3 higher risk of dying than those treated. Relapses occurred less frequently and later in patients given continuous maintenance treatment (23 out of 113; 17 months) than in untreated patients (13 out of 16; 3 months) or those given discontinuous therapy (22 out of 40; 7 months), whereas survival was independent from treatment. CMV infection was found in 97 out of 134 patients at autopsy, but was unassociated with relapse. CONCLUSIONS: CMV is a severe disease whose frequency is higher in severely immunodepressed patients. Continuous treatment leads to a lower relapse rate even if it does not change survival or eradicate the infection.

AIDS-Related Opportunistic Infections↗
PubMed1997

Hepatic histology of patients with HIV infection and chronic hepatitis C treated with interferon.

AIMS: To evaluate the histological changes seen in liver biopsies after interferon (IFN) treatment in patients with chronic hepatitis C and human immunodeficiency virus (HIV) infection. METHODS: Twenty four intravenous drug users with chronic hepatitis C were investigated histologically before beginning a 12 month course of IFN treatment and 18 months later. Twelve were HIV positive, without opportunistic or other viral infections (group A), and 12 were HIV negative (group B). RESULTS: According to alanine amino-transferase concentrations, four sustained responders and eight non-responders were found in group A; six sustained responders, five relapsers, and one non-responder were found in group B. HCV RNA became negative in one sustained responder of group A and in the six sustained responders of group B. When histological findings of biopsies performed before therapy and 18 months later were compared, no significant changes in the mean value of Knodell's index and subindices were found in group A, whereas in group B Knodell's index, piecemeal necrosis, and focal hepatocellular necrosis decreased significantly. CONCLUSIONS: In chronic hepatitis C, coinfection with HIV showed a tendency towards a lower response to IFN, although this did not reach statistical significance; however, none of the HIV positive patients developed cirrhosis during the follow up and this should be considered in clinical management of such patients.

Adult↗
PubMed1996

JCV-DNA and BKV-DNA in the CNS tissue and CSF of AIDS patients and normal subjects. Study of 41 cases and review of the literature.

SUMMARY: We studied the distribution and localization of the human papova-viruses JCV and BKV in the central nervous system (CNS) and cerebrospinal fluid (CSF) of HIV-positive patients with and without progressive multifocal leukoencephalopathy (PML) as compared with HIV-seronegative patients. The presence of JCV-DNA and BKV-DNA was evaluated by nested polymerase chain reaction (PCR) and in situ hybridization (ISH) on CNS autopsy tissues of AIDS patients with (group A, n = 13) and without (group B, n = 16) PML and of HIV-negative patients (group C, n = 12). PCR for JCV-DNA and BKV-DNA was also performed on CSF samples collected 7-420 days before death in all the 29 AIDS patients. Tissue PCR for JCV-DNA was positive in all the cases in group A, in 44 percent of the patients in group B, and in 33 percent of the patients in group C. ISH was positive in all the cases with PML and in three AIDS cases without PML (12 percent), but negative in all the HIV-negative cases. BKV-DNA was detected in two cases from group A and in one case from group B. CSF was PCR-positive for JCV-DNA in 8 of 13 (62 percent) AIDS patients with PML, but in none of the HIV patients without PML, irrespective of the presence of JCV-DNA in CNS tissues. No CSF sample was positive for BKV-DNA. Our data demonstrates that JCV-DNA and, rarely, BKV-DNA can be detected in the CNS of immunocompromised patients with and without PML and also in the CNS of HIV-negative subjects. However, only HIV-positive patients with clinically evident PML and JCV-DNA in the brain have PCR-detectable JCV-DNA in their CSF.

AIDS-Related Opportunistic Infections↗
PubMed1996

Clinical diagnosis of mycobacterial diseases versus autopsy findings in 350 patients with AIDS.

Three-hundred fifty consecutively autopsied AIDS patients in Milan, Italy, were studied to determine the frequencies of clinical and postmortem diagnoses of mycobacterial diseases, to evaluate the clinical histories of those patients with mycobacterial diseases, and to investigate the reasons for nondiagnosis of mycobacterial diseases during life. Seventy-eight patients (22.3%) had mycobacterial diseases. In 64 cases (18.3%) the diagnosis was made antemortem and in 50 (14.2%) at autopsy; there were 36 cases of concordant clinical and postmortem diagnoses. Nontuberculous mycobacterioses (NTM) were diagnosed in 41 patients (20 clinical/postmortem diagnoses, 11 clinical diagnoses, and 10 postmortem diagnoses), extrapulmonary tuberculosis (TB) in 19 patients (7 clinical/postmorten, 8 clinical, 4 postmortem), and pulmonary TB in 18 patients (9 clinical/postmorten, 9 clinical). Patients with a clinical diagnosis of mycobacteriosis but with no pathological evidence of disease at autopsy were considered to have recovered on the basis of negative culture findings and prolonged antimycobacterial treatment. In Italian patients with AIDS, NTM occurs less frequently and TB more frequently than in American AIDS patients. At least some of the patients reported in this study seemed to have recovered from mycobacterial disease after prolonged treatment. The lack of diagnosis during life can be attributed to aspecific symptoms, a rapidly terminal course, and the presence of concomitant opportunistic diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Coinfection of the central nervous system by cytomegalovirus and herpes simplex virus type 1 or 2 in AIDS patients: autopsy study on 82 cases by immunohistochemistry and polymerase chain reaction.

We evaluated the frequency and histopathological features of concomitant infections of the central nervous system (CNS) with cytomegalovirus (CMV) and herpes simplex viruses type 1 or 2 (HSV1/2) in a large series of patients who had died from AIDS. Eighty-two autopsy cases with a histological diagnosis of CMV necrotizing encephalitis were examined retrospectively. CMV and HSV1/2 were detected by immunohistochemistry (IHC) with poly- and monoclonal antibodies and by nested polymerase chain reaction (PCR) for HSV 1 and 2 on DNA extracted from paraffin blocks. PCR for a beta-globin genomic sequence was performed in all IHC-positive cases to verify the integrity of extracted DNA. Concomitant CMV/HSV infections were demonstrated by IHC in 13 cases (16%); using monoclonal antibodies, HSV1 was found in 9 cases and HSV2 in 4 cases. In half of the cases, HSV1- or HSV2-positive cells represented more than 25% of immunopositive CMV cells. In all 13 cases, double immunochemical staining showed cells containing both CMV and HSV antigens. PCR for HSV1 and 2 was positive in only 7 of 13 cases (5 HSV1 and 2 HSV2). In the remaining 6 negative cases PCR for beta-globin was also repeatedly negative. HSV1 or 2 infection can be demonstrated by IHC in a significant proportion of AIDS cases with necrotizing CMV encephalitis. Nested PCR for HSV1 and 2 on DNA extracted from formalin-fixed and paraffin-embedded autopsy tissues was positive in only slighty above 50% of IHC-positive cases.

AIDS-Related Opportunistic Infections↗
PubMed1995

Polymorphism-structure relationships of rifamexil, an antibiotic rifamycin derivative.

The polymorphism of rifamexil, a rifamycin derivative, has been investigated by thermomicroscopy, differential thermal analysis (differential scanning calorimetry-thermogravimetry), IR spectroscopy, and X-ray powder diffraction. Two crystalline forms, an amorphous material, and three solvates have been studied. The crystal structures of two solvates have also been determined by single-crystal X-ray techniques. Although the overall conformation of rifamexil is very similar in the two compounds, marked differences occur between the two crystal packings, due to differences both in the mutual orientation of the molecules and in the rifamexil-solvent interactions. Multivariate statistical methods have been used to identify the principal structural parameters determining the biological activity of the rifamycins.

Anti-Bacterial Agents↗
PubMed1991

Antibiotic GE2270 a: a novel inhibitor of bacterial protein synthesis. II. Structure elucidation.

GE2270 A, produced by Planobispora rosea ATCC 53773, inhibits Gram-positive bacteria and anaerobes by acting on the bacterial protein synthesis. The structure has been determined by physico-chemical methods applied to the intact molecule and to the main hydrolysis products. Characterization by UV, IR, NMR (double quantum filter COSY), acid-base ionization, elemental analysis and FAB-MS indicated that GE2270 A is a highly modified peptide having MW 1,289 and formula C56H55N15O10S6, and a weak basic function, and that it belongs to the thiazolyl peptide group of antibiotics. Acid hydrolysis yielded a main product (MW 634), responsible for the chromophoric absorption, and a number of hydrolyzed products of lower MW. 13C NMR inverse techniques and MS studies (EI, positive ion chemical ionization, and collision induced dissociation FAB-MS-MS experiments) on GE2270 A, the chromophoric compound, and the other hydrolysis products led to the complete identification of the various amino acid residues and their sequence. Two out of the six chiral centers have been determined. The structure is thought to originate from modification of a chain of 14 amino acids in a process which creates 6 thiazole rings and one pyridine. The modification process also closes the linear polypeptide to form a cyclic part with an attached side-chain. GE2270 A plausibly has a similar biosynthetic origin to that of other thiazolyl peptide antibiotics such as nosiheptide and micrococcin.

Actinomycetales↗
PubMed1990

[Thermoanalytic techniques for the study of pharmaceutical products].

During the past years, there have been frequent demonstrations that thermoanalytical methods have found wide-spread use in pharmacy. Analysts have developed these techniques in pharmaceutical field in the estimation of impurities, in quality control procedures, in preformulation studies, in the active principle identification, in accelerated stability and in production process optimization. Wide-spread use of thermal methods is devoted to the identification of solid state of drugs (polymorphism, solvate, inclusion compound,...) due to its possible implication on bioavailability or on the stability of a final dosage form. Some examples of thermoanalytical applications are reported.

Chemistry, Pharmaceutical↗
PubMed1978

Polymorphism of 1-methyl-2-nitro-5-vinylimidazole.

Three polymorphic forms of 1-methyl-2-nitro-5-vinylimidazole, a potential antimicrobial drug, have been isolated and characterized by thermomicroscopy, differential scanning calorimetry, infrared spectroscopy and X-ray powder diffraction. On the basis of some infrared bands, the hypothesis has been made that the different packing of forms I and II was due to the existence of the molecule in two different conformations in the two forms. The direct confirmation of the hypothesis has been sought by X-ray diffraction of single crystals, but a suitable crystal was obtained only for form II. Form II is orthorhombic, space group Pbca, with unit-cell dimensions: a = 13.05, b = 10.83, c = 10.21 A; Z = 8. From the X-ray analysis, carried out by direct methods, the molecule is planar and the vinyl group is cisoid to the heterocyclic CH group. Then, the existence of the molecule as transoid conformation in form I still remains a hypothesis.

Calorimetry, Differential Scanning↗
PubMed1977

Polymorphism of rifampicin.

The antibiotic rifampicin shows polymorphism. Two crystalline forms, an amorphous form and four solvates (S I and S II from water; S III from tetrahydrofuran; S IV from carbon tetachloride) have been isolated and characterized by thermal analysis, infrared and X-ray powder spectroscopy. The functional I.R. bands have been interpreted as indicative of some structural features involved in the polymorphism: the intramolecular H-bonds between C23--OH and O=C--O--C25, C4--OH and O=C11, and C1--OH and O=C15. The relative physical stabilities of the various forms are reported.

Crystallization↗
PubMed1977

Polymorphism and H-bonding of 2-[1(2H)-oxo-2-phthalazinyl]methylbenzoic acid.

The three crystalline and one amorphous forms of the title compound, so far isolated, have been characterized by differential scanning calorimetry, thermomicroscopy, infrared spectroscopy and X-ray powder diffraction. From I was obtained by solidification of the melt at 200 degrees; form II by crystallization from water/ethanol 1/1; form III by grinding of II; the amorphous form by rapid cooling of the melt or by evaporation to dryness of a chloroform solution. From II melts of about 200 degrees and immediately crystallizes into form I, which melts at 210 degrees. Form III transforms into I at 165 degrees. The infrared spectra of form I is different from that of forms II and III, while each form has a different X-ray powder diffraction. From consideration of the infrared functional absorption bands, it can be derived that form I is a dimer with H-bonds between the carboxylic groups, forms II and III are monomers with intramolecular H-bond between the carboxylic group and the hydrazide carbonyl, displaying different crystal packings, and the amorphous form is a mixture of both monomers and dimers, the latters in greater amount.

Benzoates↗