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Biomedical subjects

L Vago

Publications and source records attributed to L Vago.

At least 37 records · Page 2Linked to original sources
PubMed1999

Is routine histological evaluation an accurate test for Helicobacter pylori infection?

AIM: To compare the diagnostic accuracy of routine histology for Helicobacter pylori infection, with histology by an expert pathologist, and to compare histology with the rapid urease test (RUT), 13C-urea breath test, IgG serology and culture of antrum and corpus specimens, in a consecutive series of untreated patients presenting for upper oesophago-gastro-duodenoscopy. MATERIALS AND METHODS: One-hundred and fifteen consecutive patients underwent multiple tests for H. pylori infection: rapid urease test, 13C-urea breath test, IgG serology and histology and culture on antrum and corpus biopsy specimens. Histology was first evaluated by the pathologists in a routine examination, and then blindly reviewed by an expert pathologist with a special interest in gastrointestinal pathology. The patients were considered to be H. pylori-positive if two or more tests were positive. RESULTS: Eighty-one patients (70.4%) were found to be H. pylori positive. 13C-urea breath test and IgG serology showed the best sensitivity and specificity (100%). Both the antral and body cultures, and the rapid urease test had the highest specificity (100%). Histological diagnosis after re-evaluation by an expert pathologist showed a high sensitivity (98. 8%) and specificity (100%), and was better than routine histology (sensitivity 92.6%; specificity 90.3%). The accuracy of the rapid urease test was greater than that of routine histology, and the combination of these two tests improved the sensitivity of H. pylori detection to up to 100%. CONCLUSION: All diagnostic tests usually utilised in clinical practice have a sensitivity higher than 90%. In patients who were not pre-treated with antisecretory agents or antibiotics, the sensitivity of histological diagnosis, however, seems to be influenced by the accuracy of the histological examination. The sensitivity of routine histology, but not of revised histological diagnosis, is improved by an additional rapid urease test.

Breath Tests↗
PubMed1999

Human herpesvirus 6 in cerebrospinal fluid of patients infected with HIV: frequency and clinical significance.

The objective was to evaluate the frequency of human herpesvirus 6 (HHV-6) DNA detection in the CSF of patients infected with HIV and its relation to brain disease and systemic HHV-6 infection. Nested polymerase chain reaction (PCR) was used to analyse CSF samples from 365 consecutive HIV infected patients with neurological symptoms. When available, plasma and brain tissues from patients whose CSF was HHV-6 positive were also studied. HHV-6 was found in the CSF of eight of the 365 patients (2.2%): two had type A and four type B; the HHV-6 variant could not be defined in the remaining two. All eight patients had neurological symptoms and signs related to concomitant opportunistic brain diseases, including cytomegalovirus (CMV) encephalitis in five patients whose CSF was also positive for CMV-DNA. Opportunistic infections but no other unexplained lesions were also found in the brain of all of the four patients who underwent neuropathological examination. Both HHV-6 and CMV were also detected in the plasma of respectively five and seven of seven patients whose CSF was HHV-6 positive. In conclusion, HHV-6 type A or B DNA was infrequently found in the CSF of HIV infected patients, in association with both CMV brain infection and systemic HHV-6 replication. However, no certain relation between HHV-6 and brain disease was found.

Adult↗
PubMed1999

Use of magnetic beads for tissue DNA extraction and IS6110 Mycobacterium tuberculosis PCR.

Polymerase chain reaction (PCR) techniques are used increasingly for the diagnosis of Mycobacterium tuberculosis infection and can be used on the DNA obtained from both frozen and formalin fixed, paraffin wax embedded tissues. However, the extraction of DNA by means of the conventional phenol/chloroform method is time consuming and requires the use of potentially dangerous chemical reagents. This paper describes a method based upon the use of magnetic beads for the extraction of M tuberculosis DNA from both routinely formalin fixed, paraffin wax embedded tissues and frozen tissues. Magnetic bead extracted DNA from brain, lymph node, and lung tissues collected from patients with human immunodeficiency virus and tuberculosis was compared with that extracted using the phenol/chloroform method. The magnetic bead extraction procedure requires less than two hours, including the time necessary to dewax the tissue sections. In all cases, the DNA extracted with both methods was amplified successfully by PCR for the M tuberculosis IS6110 sequence. Magnetic bead DNA extraction can be used on both frozen and archival tissues: the method is reliable, simple, sensitive, and rapid; in addition, it does not use hazardous procedures or specialised laboratory equipment and can be used for routine DNA isolation from various human tissues.

Brain↗
PubMed1999

Detection and typing of JC virus in autopsy brains and extraneural organs of AIDS patients and non-immunocompromised individuals.

The distribution of JC virus (JCV) variants in the brain, lung, liver, kidney, spleen and lymph nodes collected at autopsy from AIDS patients with (Group A: 10 Ss) and without (Group B: 5 Ss) progressive multifocal leukoencephalopathy (PML) and from HIV-negative patients (Group C: 5 Ss), was examined by amplifying the JCV large T antigen (LT), the regulatory (R) and the VP1 regions. Among the samples from the PML patients, JCV DNA was detected in all of the demyelinating areas, in 60% of the lesion-free brain tissues, in 60% of the lung tissues and in 40% of the spleen and kidney tissues, whereas all liver and lymph node sections were negative. JCV DNA was also found in two of the five brain specimens, in two of the five kidney specimens, in one of the five lung specimens from the HIV-positive patients without PML and in the brain specimens from two of the five HIV-negative subjects. Nucleotide sequence analysis indicated that all of the R region amplified from extraneural tissues had rearrangements similar to those of the Mad-4 strain and that VP1-region amplified products were similar to the Mad-1 strain. In the brain specimens from two PML patients, we found a unique rearranged R region, along with a VP1 region of JCV type 2. In addition, an almost unique variant with multiple rearrangements in the R region and unusual base mutations in the VP1 region was detected in the brain sample from another PML patient. The data indicate that diffuse visceral involvement of JCV is particularly frequent in AIDS patients with PML. Moreover, the presence of rearrangements and mutations, involving different regions of the viral genome, observed in PML-affected brain tissues, could represent a risk factor for the development of PML in immunosuppressed individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1999

BK virus renal infection in a patient with the acquired immunodeficiency syndrome.

BACKGROUND: We describe herein a patient with the acquired immunodeficiency syndrome and renal failure due to biopsy-proven BK virus (BKV) infection. Three months after the diagnosis of the renal viral infection, his condition remained unchanged. Although BKV has previously been shown to be associated with ureteral stenosis and renal damage in renal transplant patients, to our knowledge, the literature contains only 3 cases describing the presence of BKV lesions in the kidneys of immunosuppressed patients who had not undergone transplantation. METHODS: The presence of BKV infection was demonstrated by means of histology, immunohistochemistry with polyclonal anti-SV40 antibody, immunoelectron microscopy, polymerase chain reaction, and enzymatic cleavage with BamHI. RESULTS: Histologic examination revealed interstitial inflammatory infiltrates and tubules with enlarged and eosinophilic nuclei. CONCLUSIONS: The high frequency of latent BKV infection and its reactivation during immunosuppression suggest that the possibility of its involvement in renal damage should be considered in immunocompromised patients.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Changes in peritoneal membrane after continuous ambulatory peritoneal dialysis--a histopathological study.

Peritoneal membrane changes in continuous ambulatory peritoneal dialysis (CAPD) patients have been widely described but poorly classified. Our aim was to identify the morphological changes occurring after CAPD treatment. To this end, 17 biopsies of parietal peritoneum (1 cm in diameter) were withdrawn at least 5 cm from the catheter entry hole and stained with Van Gieson, hematoxylin-eosin, trichrome, and some immunohistochemical stains: keratin, vimentin, CD34, CD20, CD4, CD8, desmin, and collagen IV. The morphology of mesothelium, vessels, and basement membrane (BM) of mesothelium and vessels, the presence of inflammatory cells, fibrin, and calcifications, and the distribution and thickness of submesothelial tissue were evaluated. Patients were divided into three groups according to the thickness of the sclerotic band replacing mesothelium: group 1, band up to 40 microns; group 2, band less than 40 microns; group 3, no sclerotic band. The main histopathological alterations noted were: loss of mesothelium; sclerotic alteration of vessels or duplication of BM; presence of myofibroblasts; and presence of inflammatory cells (sparse, focal, or perivascular), mainly represented by macrophages and CD4+ lymphocytes. No significant qualitative differences were observed between the three groups. In conclusion, the variable histological changes in peritoneal membrane suggest a routine peritoneal biopsy in any surgical procedure to better understand pathological changes in the course of CAPD treatment.

Adult↗
PubMed1999

Mixed follicular and parafollicular thyroid carcinoma.

A rare case of mixed follicular-parafollicular thyroid carcinoma which occurred in a 50-year-old man, is reported. The ultrastructural aspects of the tumor showed: a biphasic growth pattern with microfolliculi and solid areas; the coexpression of thyroglobulin and calcitonin antigens in the same follicle-like structures; the presence of neuroendocrine granules, microvilli and intracytoplasmic canaliculi bordered by microvilli. These characteristics lead us to a diagnosis of mixed follicular-parafollicular thyroid carcinoma.

Adenocarcinoma, Follicular↗
PubMed1998

Elevated cerebrospinal fluid levels of monocyte chemotactic protein-1 correlate with HIV-1 encephalitis and local viral replication.

OBJECTIVE: To investigate whether the CC-chemokine monocyte chemotactic protein (MCP)-1 could play a role in the pathogenesis of HIV infection of the central nervous system. This hypothesis was suggested by previous observations, including our finding of elevated cerebrospinal fluid (CSF) levels of this chemokine in patients with cytomegalovirus (CMV) encephalitis. DESIGN AND METHODS: CSF levels of MCP-1 were determined in 37 HIV-infected patients with neurological symptoms, and were compared with both the presence and severity of HIV-1 encephalitis at post-mortem examination and CSF HIV RNA levels. MCP-1 production by monocyte-derived macrophages was tested after in vitro infection of these cells by HIV. RESULTS: CSF MCP-1 levels were significantly higher in patients with (median, 4.99 ng/ml) than in those without (median, 1.72 ng/ml) HIV encephalitis. Elevated CSF MCP-1 concentrations were also found in patients with CMV encephalitis and with concomitant HIV and CMV encephalitis (median, 3.14 and 4.23 ng/ml, respectively). HIV encephalitis was strongly associated with high CSF MCP-1 levels (P = 0.002), which were also correlated to high HIV-1 RNA levels in the CSF (P = 0.007), but not to plasma viraemia. In vitro, productive HIV-1 infection of monocyte-derived macrophages upregulated the secretion of MCP-1. CONCLUSIONS: Taken together, these in vivo and in vitro findings support a model whereby HIV encephalitis is sustained by virus replication in microglial cells, a process amplified by recruitment of mononuclear cells via HIV-induced MCP-1.

Adult↗
PubMed1998

Cerebrospinal fluid HIV-1 RNA levels: correlation with HIV encephalitis.

OBJECTIVE: Neuropathological abnormalities induced by HIV-1 are not always predictable on the basis of the presence of HIV-related neurological symptoms. HIV-1 RNA load was measured in the cerebrospinal fluid (CSF) of HIV-infected patients to verify whether it could be a marker of HIV-induced neuropathology. DESIGN AND METHODS: Histopathological and immunohistochemical examination of the brain for HIV-1 p24 antigen was performed in 50 HIV-infected patients with neurological symptoms; patients were defined as having HIV encephalitis in the presence of HIV-related lesions or HIV-1 p24 antigen-positive cells. Quantitative polymerase chain reaction for HIV-1 RNA was retrospectively applied to CSF samples that had been drawn 1-60 days prior to death from these 50 patients; paired plasma samples of 28 patients were also analysed. RESULTS: The CSF HIV-1 RNA copy numbers were significantly higher in 22 patients with HIV encephalitis than in 28 patients without (median, 4.77 log10 versus 3.45 log10 copies/ml; P = 0.0003). No correlation was found between CSF HIV-1 RNA load and the presence of opportunistic brain pathologies at post-mortem examination or between HIV-1 RNA loads in paired CSF and plasma samples. CONCLUSIONS: High CSF HIV-1 RNA levels are associated with HIV encephalitis, regardless of the presence of opportunistic brain diseases or HIV-1 RNA levels in plasma. Quantitative CSF HIV-1 RNA may therefore be used as a specific marker of HIV-induced neuropathology.

AIDS Dementia Complex↗
PubMed1998

Epstein-Barr virus DNA in the cerebrospinal fluid of an HIV patient with primary cerebral lymphoma.

UNLABELLED: The case of a 7-month-old boy with vertically acquired immunodeficiency syndrome and multifocal primary cerebral lymphoma is reported. Neither neurological nor neuroradiological findings contributed towards the appropriate diagnosis. Positive Epstein-Barr virus DNA, assessed by means of polymerase chain reaction in cerebrospinal fluid, strongly suggested a diagnosis of primary cerebral lymphoma, which was subsequently confirmed by autopsy. CONCLUSIONS: The detection of Epstein-Barr virus DNA using the polymerase chain reaction in cerebrospinal fluid is useful for the diagnosis of primary cerebral lymphoma.

Brain↗
PubMed1998

Effects of Helicobacter pylori eradication on gastric function indices in functional dyspepsia. A prospective controlled study.

BACKGROUND: To date, it is unclear whether Helicobacter pylori infection is associated with disturbances of gastric emptying or acid secretion in patients with functional dyspepsia (FD). Our aim was to investigate whether, in the long run, cure of H. pylori infection significantly influences gastric emptying of solids, acid secretion, and gastrin and pepsinogen I (PGI) release in patients with FD. METHODS: Thirty-eight consecutive H. pylori-positive patients with FD, whose complaints were scored for severity and frequency on the basis of a validated symptom questionnaire, were initially enrolled in the study. They were randomized to receive an eradicating regimen consisting of omeprazole plus clarithromycin and tinidazole for 1 week or full-dose ranitidine for 3 weeks. In 33 patients (18 H. pylori-cured and 15 with persistent infection) basal and pentagastrin-stimulated acid secretion, fasting and meal-induced gastrin concentrations, fasting serum PGI levels, and gastric emptying of solids were determined before and 6 months after therapy. RESULTS: In the 18 H. pylori-cured patients meal-induced gastrin and fasting PGI levels were significantly reduced after 6 months as compared with pretreatment values (peak serum gastrin, 76.0 +/- 23.4 versus 111.9+/-37.4 pg/ml; PGI, 57.1+/-23.4 versus 72.9+/-29.1 ng/ml), whereas they remained virtually unchanged in the 15 patients with persistent infection. In contrast, both basal and stimulated acid secretion and gastric emptying time of solids remained unmodified over time in both groups of patients. CONCLUSIONS: We confirm that also in patients with functional dyspepsia H. pylori eradication in the long run significantly reduces gastrin and PGI release as a result of improvement in the underlying antral gastritis, but this is not accompanied by modifications of gastric emptying of solids or acid secretion.

Adult↗
PubMed1998

Herpes simplex virus infections of the central nervous system in human immunodeficiency virus-infected patients: clinical management by polymerase chain reaction assay of cerebrospinal fluid.

A duplex polymerase chain reaction (PCR) assay for DNA from herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) was applied to cerebrospinal fluid (CSF) from 918 human immunodeficiency virus (HIV)-infected patients with neurological symptoms. HSV-1 or HSV-2 (HSV-1/2) DNA was found in 19 patients (2%). For the 258 patients for whom a diagnosis was confirmed at autopsy, the sensitivity and specificity of PCR analysis for the diagnosis of HSV-1/2 encephalitis were 100% and 99.6%, respectively. Three patients with CD4+ cell counts of > or = 170/microL had HSV-1 central nervous system (CNS) infections (two) or HSV-2 meningitis (one). Sixteen patients with CD4+ cell counts of < 40/microL had HSV-1 CNS infections (two) or mixed HSV-1/2 and cytomegalovirus encephalitis (14). The response to antiviral treatment, which was assessed clinically and by CSF PCR analysis, was variable in the patients with the highest CD4+ cell counts and poor in those with more severe immunosuppression. CSF PCR analysis is of value for the diagnosis and follow-up of treatment of HSV-1/2 CNS infections in HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Microglial nodular encephalitis and ventriculoencephalitis due to cytomegalovirus infection in patients with AIDS: two distinct clinical patterns.

In patients with AIDS, cerebral infection due to cytomegalovirus (CMV) results in two distinct neuropathological patterns: microglial nodular encephalitis (MGNE) and ventriculoencephalitis (VE). In order to identify clinical features to facilitate the differential diagnosis of these two forms of CMV encephalopathy in living patients, we retrospectively reviewed the clinical records of 18 patients with MGNE or VE diagnosed at autopsy. We identified the following clinical features as distinguishing the two encephalopathies: (1) MGNE manifests earlier than VE; (2) the onset of MGNE is acute, whereas the onset of VE is insidious; (3) the onset of MGNE is marked by confusion and delirium, which do not occur in VE; (4) VE is frequently associated with radiculopathy, which is absent in MGNE; and (5) VE is associated with more marked alterations in cerebrospinal fluid (high protein levels and pleocytosis). The early neurological manifestations of MGNE should prompt a search for systemic CMV infection, which may lead to earlier treatment.

AIDS-Related Opportunistic Infections↗
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

Influence of bacterial CagA status on gastritis, gastric function indices, and pattern of symptoms in H. pylori-positive dyspeptic patients.

OBJECTIVE: To date, little is known about a possible relationship between H. pylori-related disturbances of gastric function and the bacterial virulence. The aim of this study was to assess whether certain gastric function indices as well as the pattern of symptoms in nonulcer dyspepsia (NUD) are related to CagA status. METHODS: A total of 56 consecutive patients with NUD (38 H. pylori-positive and 18 H. pylori-negative) were studied. Dyspeptic symptoms were categorized according to the predominant complaints and scored for severity and frequency. In all subjects, basal and pentagastrin-stimulated acid secretion, fasting and meal-induced gastrin release, fasting serum pepsinogen I (PG I) levels, and gastric emptying of solids were determined. CagA status was determined by assaying serum CagA IgG antibodies by western blotting. RESULTS: Eighteen of 38 (47%) H. pylori-positive dyspeptics were CagA seropositive. Type and severity of dyspeptic symptoms did not significantly differ between CagA-positive and CagA-negative dyspeptics nor between H. pylori-positive and negative patients. Among the gastric function indices studied, only meal-stimulated gastrin was significantly influenced by CagA status (peak gastrin 129.9 [44.1] vs 99.1 [48.6] pg/ml in CagA-positive and negative NUD, respectively), but this was not accompanied by any significant modification of basal or stimulated acid secretion or gastric emptying of solids. The activities of both antral and corpus gastritis in NUD harboring CagA-positive strains were significantly higher than those of CagA-negative NUD. Accordingly, serum PG I levels were significantly higher in CagA-positive than CagA-negative or H. pylori-negative dyspeptics. CONCLUSIONS: These findings support a role for CagA status in influencing the activity and perhaps the distribution of gastritis in NUD, as well as the degree of gastrin response to a meal; however, this is not accompanied by disturbances of acid secretion or gastric emptying or by differences in the type and severity of symptoms.

Adult↗
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

Primary liver adenomatosis. Report of two cases and literature review.

BACKGROUND/AIMS: Liver adenomatosis is an uncommon condition and so far only 13 cases fulfilling the requirements for its diagnosis have been reported in the literature. Optimal treatment of the disease and follow-up criteria are still the subject of debate. METHODS: We report on 2 cases of liver adenomatosis. In both cases definite diagnosis was obtained only intraoperatively on biopsy. RESULTS: In neither case was liver transplantation done, due either to patient refusal or foreseeable poor compliance. Prolonged strict follow-up failed to demonstrate malignant changes. CONCLUSIONS: Removal of the huge masses often responsible for abdominal pain is the only real indication for resective surgery. Orthotopic liver transplantation should be reserved for those cases in which malignant changes are suspected due to elevation of the alpha-fetoprotein concentration or gross modifications in the shape of the hepatic lesions.

Adenoma↗