Biomedical subjects

J Albert

Publications and source records attributed to J Albert.

At least 37 records · Page 2Linked to original sources

PubMed2001

Epidemiology of HIV in Estonia.

The aim of this study was to report on the epidemiology of HIV infection in Estonia and to molecularly characterize Estonian HIV-1 variants. Epidemiological data were obtained from the Estonian National HIV/AIDS Database. In 1995-1996 blood samples were collected from 54 of the 65 HIV-infected individuals that had been diagnosed at that time. The V3 domain of the env gene was directly sequenced from peripheral blood mononuclear cells of 49 of these 54 individuals and the sequences used for phylogenetic analyses. At the end of 1999 Estonia reported 96 diagnosed HIV cases; 46 (48%) were homosexual or bisexual men and 31 (32%) were presumed to have been infected heterosexually. Importantly, only four individuals were likely to have become infected through intravenous drug use. Forty-three individuals (45%) were presumed to have been infected outside of Estonia, whereas 38 (40%) were likely to have become infected in Estonia. As expected, a majority of the investigated individuals (80%) were found to carry subtype B virus. Infections with subtypes A, C, D, G, and CRF02_AG were also documented. The dominance of subtype B was restricted to homosexual and bisexual men. Thus, subtype B infections were documented in 33 of 34 (97%) homosexual and bisexual men, but only 6 of 15 (40%) individuals with other probable routes of infection. Thirty of the 39 subtype B sequences were joined in a tight sequence cluster that also included sequences from neighboring Russia and Lithuania. This pattern suggests a local spread of HIV-1 among homosexual and bisexual men within the region. The results from the phylogenetic analyses agreed well with other epidemiological information. In conclusion, Estonia remains a country with a low prevalence of HIV infection. A majority of the identified cases are homosexual or bisexual men, whereas HIV infection among intravenous drug users is rare. A large proportion of the homosexual and bisexual men carried closely related subtype B variants. The sequences have been deposited in GenBank under accession numbers AF286538-AF286586.

Adolescent↗

PubMed2001

Regional brain and ventricular volumes in Tourette syndrome.

BACKGROUND: The pathophysiology of Tourette syndrome (TS) is thought to involve disturbances in cortico-striato-thalamo-cortical circuitry. The morphological characteristics of the cortical and associated white matter portions of these circuits have not been previously examined in TS subjects. METHODS: High-resolution anatomical magnetic resonance images were acquired in 155 TS and 131 healthy children and adults. The cerebrums and ventricles were isolated and then parcellated into subregions using standard anatomical landmarks. RESULTS: For analyses that included both children and adults, TS subjects were found to have larger volumes in dorsal prefrontal regions, larger volumes in parieto-occipital regions, and smaller inferior occipital volumes. Significant inverse associations of cerebral volumes with age were seen in TS subjects that were not seen in healthy controls. Sex differences in the parieto-occipital regions of healthy subjects were diminished in the TS group. The age-related findings were most prominent in TS children, whereas the diminished sex differences were most prominent in TS adults. Group differences in regional ventricular volumes were less prominent than in the cerebrum. Regional cerebral volumes were significantly associated with the severity of tic symptoms in orbitofrontal, midtemporal, and parieto-occipital regions. CONCLUSIONS: Broadly distributed cortical systems are involved in the pathophysiology of TS. Developmental processes, sexual dimorphisms, and compensatory responses in these cortical regions may help to modulate the course and severity of tic symptoms.

Adolescent↗

PubMed2001

Nocturnal home hemodialysis in North America.

Nocturnal home hemodialysis (NHD) was made possible in the 1960s by fail-safe monitoring, the Scribner shunt, and low-resistant Kiil dialyzer allowing hemodialysis without a blood pump. In London, Sheldon was the first to use overnight home hemodialysis. The Lynchburg NHD program and Lisa Murphy, a dietician in Bender's NHD program in Kansas City, developed a questionnaire for short daily hemodialysis and NHD. The questionnaire was sent to all known daily hemodialysis programs in North America. Some advances in nocturnal home hemodialysis since 1994 include: improvement in teaching methods, preventing disconnects and air emboli, preventing catheter infections, and using arteriovenous fistulas and grafts for access. As of January 2001, there were 13 centers in North America performing daily nocturnal home hemodialysis caring for 115 patients. Since 1997, all programs performing NHD have validated Pierratos' reported results, showing improvement in quality of life, better blood pressure control with fewer medications, reduced Epogen usage, reduced hospitalizations, control of phosphorous without binders, and a greater sense of hope for patients. Even though this new modality is safe and better for selected patients with ESRD, dialysis providers in Canada and the United States cannot afford to offer NHD within the present reimbursement scheme.

Canada↗

PubMed2001

Characterization of Chlamydia trachomatis omp1 genotypes among sexually transmitted disease patients in Sweden.

A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed. DNA was extracted from urogenital or urine samples using a Chelex-based method, and an approximately 1,100-bp-long fragment from the omp1 gene was directly amplified and sequenced. Genotyping was performed by BLAST similarity search, and phylogenetic tree analysis was used to illustrate the evolutionary relationships between clinical isolates and reference strains. The method was used to determine the genotypes of C. trachomatis in 237 positive urogenital and/or urine specimens collected at a Swedish sexually transmitted disease clinic during 1 year. The most common genotypes corresponded to serotypes E (47%) and F (17%). The omp1 gene was highly conserved for genotype E (106 of 112 samples without any mutation) and F (41 of 42 samples without any mutation) strains but appear slightly less conserved for genotypes G (n = 6) and H (n = 6), where the sequences displayed one to four nucleotide substitutions relative to the reference sequence. Genotyping of samples collected at the follow-up visit indicated that two patients had become reinfected, while three other patients suffered treatment failure or reinfection. One woman appeared to have a mixed infection with two different C. trachomatis strains. This omp1 genotyping method had a high reproducibility and could be used for epidemiological characterization of sexually transmitted Chlamydia infections.

Adolescent↗

PubMed2001

Monitoring resistance to human immunodeficiency virus type 1 protease inhibitors by pyrosequencing.

The emergence of drug-resistant viral variants is the inevitable consequence of incomplete suppression of human immunodeficiency virus type 1 (HIV-1) replication during treatment with antiretroviral drugs. Sequencing to determine the resistance profiles of these variants has become increasingly important in the clinical management of HIV-1 patients, both in the initial design of a therapeutic plan and in selecting a salvage regimen. Here we have developed a pyrosequencing assay for the rapid characterization of resistance to HIV-1 protease inhibitors (PIs). Twelve pyrosequencing primers were designed and were evaluated on the MN strain and on viral DNA from peripheral blood mononuclear cells from eight untreated HIV-1-infected individuals. The method had a limit of detection of 20 to 25% for minor sequence variants. Pattern recognition (i.e., comparing actual sequence data with expected wild-type and mutant sequence patterns) simplified the identification of minor sequence variants. This real-time pyrosequencing method was applied in a longitudinal study monitoring the development of PI resistance in plasma samples obtained from four patients over a 2 1/2-year period. Pyrosequencing identified eight primary PI resistance mutations as well as several secondary mutations. This sequencing approach allows parallel analysis of 96 reactions in 1 h, facilitating the monitoring of drug resistance in eight patients simultaneously and, in combination with viral load analysis, should be a useful tool in the future to monitor HIV-1 during therapy.

Acquired Immunodeficiency Syndrome↗

PubMed2001

Diagnostics of neisseriaceae and moraxellaceae by ribosomal DNA sequencing: ribosomal differentiation of medical microorganisms.

Fast and reliable identification of microbial isolates is a fundamental goal of clinical microbiology. However, in the case of some fastidious gram-negative bacterial species, classical phenotype identification based on either metabolic, enzymatic, or serological methods is difficult, time-consuming, and/or inadequate. 16S or 23S ribosomal DNA (rDNA) bacterial sequencing will most often result in accurate speciation of isolates. Therefore, the objective of this study was to find a hypervariable rDNA stretch, flanked by strongly conserved regions, which is suitable for molecular species identification of members of the Neisseriaceae and Moraxellaceae. The inter- and intrageneric relationships were investigated using comparative sequence analysis of PCR-amplified partial 16S and 23S rDNAs from a total of 94 strains. When compared to the type species of the genera Acinetobacter, Moraxella, and Neisseria, an average of 30 polymorphic positions was observed within the partial 16S rDNA investigated (corresponding to Escherichia coli positions 54 to 510) for each species and an average of 11 polymorphic positions was observed within the 202 nucleotides of the 23S rDNA gene (positions 1400 to 1600). Neisseria macacae and Neisseria mucosa subsp. mucosa (ATCC 19696) had identical 16S and 23S rDNA sequences. Species clusters were heterogeneous in both genes in the case of Acinetobacter lwoffii, Moraxella lacunata, and N. mucosa. Neisseria meningitidis isolates failed to cluster only in the 23S rDNA subset. Our data showed that the 16S rDNA region is more suitable than the partial 23S rDNA for the molecular diagnosis of Neisseriaceae and Moraxellaceae and that a reference database should include more than one strain of each species. All sequence chromatograms and taxonomic and disease-related information are available as part of our ribosomal differentiation of medical microorganisms (RIDOM) web-based service (http://www.ridom.hygiene.uni-wuerzburg.de/). Users can submit a sequence and conduct a similarity search against the RIDOM reference database for microbial identification purposes.

DNA, Ribosomal↗

PubMed2001

Antigenic variation within the CD4 binding site of human immunodeficiency virus type 1 gp120: effects on chemokine receptor utilization.

To assess the antigenicity of envelope glycoproteins derived from primary human immunodeficiency virus type 1 populations, their interactions with the receptor CD4, and their coreceptor usage, we have cloned and expressed multiple gp120 proteins from a number of primary virus isolates. Characterization of these proteins showed a high degree of antigenic polymorphism both within the CD4 binding site and in defined neutralization epitopes, which may partially account for the general resistance of primary isolates to neutralizing agents. Furthermore, chimeric viruses expressing gp120 proteins with reduced CD4 binding abilities are viable, suggesting that primary viruses may require a less avid interaction with the receptor CD4 to initiate infection than do their laboratory-adapted counterparts. The coreceptor usage of chimeric viruses was related to the ability of the virus to bind CD4, with reduced CD4 binding correlating with preferential usage of CXCR4. Changes in coreceptor usage mapped to sequence changes in the C2 and V4 regions, with no changes seen in the V3 region.

Amino Acid Sequence↗

PubMed2000

Multicenter ProstaScint imaging findings in 2154 patients with prostate cancer. The ProstaScint Imaging Centers.

OBJECTIVES: To report the results of a retrospective study of 2290 ProstaScint scans of 2154 patients with prostate carcinoma done at 15 institutions. METHODS: The results were analyzed by logistic regression after stratification of the patients into four groups: group 1, newly diagnosed; group 2, after radical prostatectomy with a rising prostate-specific antigen (PSA) level; group 3, after radiation therapy with a rising PSA level; and group 4, after hormonal therapy. RESULTS: The PSA level and ProstaScint scans positive in the prostate bed (P <0.001) and for pelvic metastases (P <0.001), but not for extrapelvic metastases, correlated significantly in group 1 patients. In group 2, the association for detecting fossa recurrence was weaker (P = 0.033) and was insignificant for pelvic and extrapelvic metastases. Patients in group 3 also exhibited a weak PSA-ProstaScint association for detecting fossa recurrence (P = 0.038), and was insignificant for pelvic and extrapelvic metastases. No significant PSA-ProstaScint correlation was found in patients in group 4 for fossa recurrence, pelvic or extrapelvic metastases. The distribution of positive ProstaScint results among the prostate/prostate bed, pelvic nodes, and extrapelvic nodes was nearly equal for all groups, except that a significantly greater percentage of extrapelvic metastases was found in the hormonal group (group 4). The ProstaScint results were independent of the Gleason score for 260 patients before and 285 patients after therapy. CONCLUSIONS: The results of this study underscore the complementary diagnostic value of ProstaScint to PSA level and Gleason score as an independent indicator of prostate cancer recurrence and metastases and in identifying extrapelvic metastases in both newly diagnosed and recurrent prostate cancer.

Antibodies, Monoclonal↗

PubMed2000

Plasma viral load in HIV-1 and HIV-2 singly and dually infected individuals in Guinea-Bissau, West Africa: significantly lower plasma virus set point in HIV-2 infection than in HIV-1 infection.

BACKGROUND: The intriguing differences in the natural course, transmissibility, and epidemiological characteristics of human immunodeficiency virus type 1 (HIV-1) and HIV-2 are still insufficiently explained. Differences in plasma viral load are an obvious possibility, but this has been difficult to investigate because of the lack of tests for HIV-2 RNA. OBJECTIVE: To compare plasma HIV RNA load between individuals infected with HIV-1 and HIV-2 in Guinea-Bissau, a West African country with high prevalence and incidence of HIV-1 and HIV-2 infection. METHODS: A total of 102 participants were recruited from ongoing prospective cohort studies. These included 19 HIV-1 and 29 HIV-2 seroincident cases tested at a median of less than 2 years after seroconversion as well as seroprevalent cases with single (9 HIV-1 cases and 31 HIV-2 cases) or dual (n = 14) infections. Plasma HIV RNA levels were determined by a commercial HIV-1 assay and an experimental HIV-2 assay based on the same principles. RESULTS: The viral set point, ie, the semi-equilibrium reached after seronconversion, was 28-fold lower in recent HIV-2 seroconverters than in recent HIV-1 seroconverters (median, 2500 and 70,000 RNA copies per milliliter, respectively; P<. 001). This difference appeared to persist to symptomatic stages of the diseases. Dually infected individuals had lower plasma HIV-1 RNA levels than singly infected individuals. CONCLUSIONS: The differences between HIV-1 and HIV-2 infection are likely to be caused by differences in plasma viral set point and load, but the mechanisms through which HIV-2 infection is contained to a higher degree than HIV-1 remain to be identified. Arch Intern Med. 2000;160:3286-3293.

Acquired Immunodeficiency Syndrome↗

PubMed2000

High plasma levels of soluble fas in HIV type 1-infected subjects are not normalized during highly active antiretroviral therapy.

Plasma levels of soluble Fas (sFas) are elevated in human immunodeficiency virus type 1 (HIV-1) infection, indicating dysregulation of the Fas apoptosis pathway and chronic immune activation. We performed a retrospective study to investigate the effects of HAART on plasma levels of sFas. A cross-sectional study of 27 drug-naive infected subjects and 49 patients under antiretroviral treatment showed that plasma levels of sFas were higher in HIV-1-infected subjects than in 52 HIV-1-negative controls, independently of the treatment status. In a longitudinal study of 69 patients undergoing HAART, we observed a minimal, but significant decrease in sFas plasma levels after 1 year of therapy. Levels of sFas, however, remained still higher than physiologic values. Patients undergoing HAART were further classified as nonresponders or responders on the basis of viremia suppression; no significant changes in plasma levels of sFas were observed between the two groups. These findings show that 1 year of HAART has a minor effect on the sFas levels in plasma. Long-term HAART may be required to normalize the dysregulation of the Fas apoptotic pathway and the persistent immune activation initiated by HIV-1.

Anti-HIV Agents↗

PubMed2000

Monoclonal antibodies to native HIV type 1 reverse transcriptase and their interaction with enzymes from different subtypes.

Recombinant reverse transcriptase (RT) from HIV-1 subtype B was used to produce mouse anti-RT monoclonal antibodies (MAbs). Immunization was done by mixing RT with the ISCOM matrix-forming adjuvant saponin (Quil A). Two different assays, both based on the interaction of native RT and antibodies, were used to monitor the immune response in mice and for screening, selection, and characterization of the MAbs. The first assay measures the capacity of antibodies to inhibit the polymerase activity of the RT and the second assay measures the ability of antibodies to capture enzymatically active RT. Twelve clones with the capacity to inhibit at least 50% of the RT activity and 34 clones with high RT-capturing capacity were found. The MAb panel was utilized to evaluate the immunological properties of 18 different RTs representing 9 different HIV1 subtypes. The RT-inhibitory MAbs could be divided into two groups based on their pattern of cross-reactivity toward the different HIV-1 RTs. The degree of diversity recorded among MAbs with RT-capturing capacity was larger. At least seven groups of MAbs with distinct cross-reactivity patterns were identified. Thus, the degree of isoenzyme specificity varied greatly, from MAbs that were quite specific for subtype B RT to one MAb that was able to capture the RTs from all HIV-1 isolates tested except one of the two group O isolates. In conclusion, our study revealed that there exist surprisingly large immunological differences between RTs from different HIV-1 subtypes as well as from the same subtype.

Animals↗

PubMed2000

Evidence of the existence of a new circulating recombinant form of HIV type 1 subtype A/J in Cameroon. The European Network on the Study of In Utero Transmission of HIV-1.

Several genetic subtypes and circulating recombinant forms (CRFs) of HIV-1 have been identified. The greatest degree of genetic diversity is displayed by variants from Central and West Africa. HIV-1 env C2-V5 and protease sequences were obtained from 15 HIV-1-infected pregnant women, who were selected from a larger cohort study in Yaoundé, Cameroon. Fourteen of 15 virus variants were shown to be recombinant, whereas a single variant appeared to be nonrecombinant subtype A. Five viruses were subtype A/J recombinants, with env genes derived from subtype A and protease genes derived from subtype J. Seven viruses clustered with reference sequences for CRF02 AG(IbNG) in both the env and protease gene fragments, and were thus subtype A/G recombinants. Two variants displayed even more complex recombination patterns. Phylogenetic analyses indicated that the five subtype A/J recombinants might be the first representatives of a previously unrecognized CRF.

Cameroon↗

PubMed2000

Pancreatic cancer detection with magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography: a prospective controlled study.

BACKGROUND: Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive and increasingly used procedure in cases involving biliary and pancreatic diseases. However, the accuracy of MRCP in differential diagnosis between pancreatic cancer and chronic pancreatitis has never been documented in a large prospective controlled study. METHODS: 124 patients were recruited for the study, selected from 141 consecutive patients with an average age of 55 years (range 19-80) who presented to our department between February, 1996, and January, 1998, with a strong clinical suspicion of pancreatic cancer. MRCP images were interpreted by a radiologist and a gastroenterologist who were unaware of the clinical diagnosis of patients. The exact diagnosis was based upon histological evidence from biopsy examination (surgical and fine needle biopsy) or a follow-up of at least 12 months. FINDINGS: Of the 124 patients, 37 (30%) had pancreatic carcinoma; 17 (14%) had other neoplastic pancreatic diseases; 57 (46%) had chronic pancreatitis; 13 (10%) pancreatic ducts were clear. The sensitivity of MRCP with respect to diagnosing pancreatic cancer was 84% and its specificity 97%. The corresponding values for endoscopic retrograde cholangiopancreatography (ERCP) were 70% and 94%, respectively. INTERPRETATION: MRCP is as sensitive as ERCP when detecting pancreatic carcinomas. Furthermore, it is feasible to presume that the use of MRCP may prevent inappropriate explorations of the pancreatic and common bileducts in cases of suspected pancreatic carcinomas, where interventional endoscopic therapy (ie, palliative common-bileduct drainage) is unlikely.

Adult↗

PubMed2000

Coreceptor usage of HIV-1 isolates representing different genetic subtypes obtained from pregnant Cameroonian women. European Network for In Utero Transmission of HIV-1.

In this study, coreceptor usage of HIV-1 other than subtype B in relation to HIV-1 transmission from mother to child was investigated. Repeated sampling of 42 HIV-1-seropositive, asymptomatic women in Cameroon during the second and third trimesters of pregnancy, at delivery, and 6 months postpartum were performed. Env subtyping was carried out from uncultured peripheral blood mononuclear cells (PBMCs) by heteroduplex mobility assay and, whenever necessary, by DNA sequencing. Virus isolates were tested for coreceptor usage on human cell lines-U87.CD4 and GHOST(3)-engineered to express stably CD4 and the chemokine receptors CCR1, CCR2b, CCR3, CCR5, or CXCR4, or the orphan receptors BOB/gpr15 or Bonzo/STRL33/TYMSTR. Transmission rate was 11.9%. Viruses were predominantly envelope subtype A and used CCR5 as coreceptor and, surprisingly, 4 of 28 (14.2%) isolates from mothers and 1 of 3 isolates from children used the orphan receptor Bonzo as well. In 2 transmitting mothers from whom sequential HIV-1 isolates were available, viral coreceptor usage evolved from CCR5 monotropic to CCR5/Bonzo dual tropic during pregnancy, and in 1 case transmission of this virus could be documented. Our data suggest that evolution of HIV-1 coreceptor usage to dual (or multi-) tropism may occur during pregnancy.

Cameroon↗

PubMed2000

Evaluation of a prototype Amplicor PCR assay for detection of human immunodeficiency virus type 1 DNA in blood samples from Tanzanian adults infected with HIV-1 subtypes A, C and D.

BACKGROUND: In previous evaluations, the standard Amplicor HIV-1 DNA PCR test (Roche Diagnostic Systems) has been reported to have low sensitivity for the detection of some non-B HIV-1 subtypes. It has therefore become necessary to determine the performance of commercially available as well as prototype HIV-1 PCR assays for HIV-1 DNA detection in samples from various geographical settings, in order to assess their ability to detect the different HIV-1 genotypes. OBJECTIVES: To determine the performance of the prototype Roche Amplicor version 1.5 PCR test in comparison to that of the standard Roche Amplicor PCR test for the detection of HIV-1 DNA in blood samples from HIV-1 seropositive pregnant Tanzanian women infected with various HIV-1 subtypes. STUDY DESIGN: This was a cross-sectional study done on 161 blood samples collected from 106 HIV-1 seropositive and 55 seronegative asymptomatic pregnant women attending antenatal clinic in Dar es Salaam, Tanzania. METHODS: Cell pellets for PCR were prepared from EDTA blood by the Amplicor whole blood PCR sample preparation method. Plasma was used for HIV serology by enzyme linked immunosorbent assays. Subtyping was done by the heteroduplex mobility assay (HMA) using cell pellets and/or plasma. RESULTS: The sensitivities of the prototype PCR and the standard assays were 99.1% (105/106) and 97% (99/102), respectively. All samples from 55 HIV-1 seronegative women were negative by both PCR assays. Among the 101 samples subtyped by HMA, 48 (47%) were subtype A, 30 (30%) subtype C, 20 (20%) subtype D and 3 (3%) were indeterminate. In the standard DNA PCR assay, a statistically significantly higher proportion of subtype A samples had a low level of reactivity as measured as optical density compared with the subtypes C and D samples while in the prototype assay all three subtypes showed a high level of reactivity. CONCLUSIONS: The Amplicor version 1.5 DNA PCR test has a high sensitivity for the detection of HIV-1 DNA in blood samples from Tanzanian adults. Since performance of this assay does not appear to be influenced by differences in HIV-1 subtypes A, C and D, it has the potential for use in the detection of HIV-1 DNA in samples from geographic areas where these subtypes are prevalent.

Adult↗

PubMed2000

Magnetic resonance imaging in gastroenterology: time to say good-bye to all that endoscopy?

Magnetic resonance imaging (MRI) has been described as the most important development in medical diagnosis since the discovery of the roentgen ray more than 100 years ago. The effectiveness of MRI has been extended to make it applicable in a wide variety of gastrointestinal disorders. The attention of gastroenterologists is currently focusing on pancreaticobiliary and bowel diseases. Magnetic resonance cholangiopancreatography (MRCP) has become a competitive alternative to diagnostic endoscopic retrograde cholangiopancreatography in a variety of hepatobiliary and pancreatic diseases. Magnetic resonance enteroscopy has the potential to become the preferable method for evaluating the entire small bowel; virtual colonoscopy, on the other hand, is far from the stage at which it could be promoted as a tool for general screening purposes in suspected colonic diseases. Its drawbacks include problems with standardization, implementation of the techniques in generalized settings, and patient acceptance.

Biliary Tract Diseases↗

PubMed2000

Mucinous cystadenomas and intraductal papillary mucinous tumors of the pancreas in magnetic resonance cholangiopancreatography.

BACKGROUND AND STUDY AIMS: In mucin-producing tumors of the pancreas, diagnosis using endoscopic retrograde cholangiopancreatography (ERCP) is limited to cystic formations that communicate with the main pancreatic duct. Magnetic resonance cholangiopancreatography (MRCP) is a new, sophisticated method which is currently under evaluation. The authors describe the usefulness of MRCP in diagnosis of mucin-producing tumors. PATIENTS AND METHODS: Six patients with mucin-producing tumors were investigated using MRCP and ERCP. Imaging was compared with surgery and histopathological examinations. RESULTS: Three patients were found to have mucinous cystadenomas (MC), two patients had intraductal papillary mucinous tumors (IPMT) and one patient had a cystadenocarcinoma. MRCP demonstrated the cystic formations in all patients. Magnetic resonance imaging (MRI) showed contrast-mediated enhancement of the cystic wall in patients with MC, and visualized the pancreatic ducts completely in patients with IPMT. ERCP failed to visualize the cystic lesion in one patient with MC of the pancreatic tail. Furthermore, ERCP showed evidence of IPMT in dilated main ducts with multiple filling defects but did not visualize the ducts completely. CONCLUSIONS: MRCP provides visualization of pancreatic ducts, extraductal variations, and cystic formations more completely than ERCP does. It avoids complications seen in ERCP. MRCP may replace ERCP in the evaluation of mucin-producing tumors of the pancreas.

Adult↗

PubMed2000

Prevalence and characteristics of multinucleoside-resistant human immunodeficiency virus type 1 among European patients receiving combinations of nucleoside analogues.

The prevalence and the genotypic and phenotypic characteristics of multinucleoside-resistant (MNR) human immunodeficiency virus type 1 (HIV-1) variants in Europe were investigated in a multicenter study that involved centers in nine European countries. Study samples (n = 363) collected between 1991 and 1997 from patients exposed to two or more nucleoside analogue reverse transcriptase inhibitors (NRTIs) and 274 control samples from patients exposed to no or one NRTI were screened for two marker mutations of multinucleoside resistance (the Q151M mutation and a mutation with a 2-amino-acid insertion at codon 69, T69S-XX). Q151M was identified in six of the study samples (1. 6%), and T69S-XX was identified in two of the study samples (0.5%; both of them T69S-SS), but both patterns were absent among control samples. Non-NRTI (NNRTI)-related changes were observed in viral strains from two patients, which displayed the Q151M resistance pattern, although the patients were NNRTI naive. The patients whose isolates displayed multinucleoside resistance had received treatment with zidovudine and either didanosine, zalcitabine, or stavudine. Both resistance patterns conferred broad cross-resistance to NRTIs in vitro and a poor response to treatment in vivo. MNR HIV-1 is found only among multinucleoside-experienced patients. Its prevalence is low in Europe, but it should be closely monitored since it seriously limits treatment options.

Amino Acid Substitution↗