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Biomedical subjects

B Leng

Publications and source records attributed to B Leng.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Xanthomonas maltophilia nosocomial infections. A new threat. Apropos of 30 cases].

In an attempt to further characterize infections due to Xanthomonas maltophilia, we reviewed 20 colonisations and 30 infections observed in our institution from january 1990 to december 1992, Xanthomonas maltophilia is emerging as an important nosocomial pathogen in immunocompromised patients, especially those receiving broad spectrum antimicrobial antibiotherapy. Distinction between colonisation and infection is often difficult. Xanthomonas maltophilia presents a therapeutic challenge because of its tendency to exhibit multiple resistance.

Anti-Bacterial Agents↗
PubMed1994

Protein secondary structure prediction using two-level case-based reasoning.

We have developed a two-level case-based reasoning architecture for predicting protein secondary structure. The central idea is to break the problem into two levels: (i) reasoning at the object (protein) level and using the global information from this level to focus on a more restricted problem space; (ii) decomposing objects into pieces (segments) and reasoning at the level of internal structures. As a last step to the procedure, inferences from the parts of the internal structure are synthesized into predictions about global structure. The architecture has been developed and tested on a commonly used data set with 69.5% predictive accuracy. It was then tested on a new data set with 68.2% accuracy. With additional tuning, over 70% accuracy was achieved. In addition, a series of experiments were conducted to test various aspects of the method and the results are informative.

Amino Acid Sequence↗
PubMed1993

HIV-1 and HCV co-infected patients: detection of active viral expression using a nested polymerase chain reaction.

The aim of the present study was to determine, in a population of 70 HIV-1 infected patients with antibodies to HCV, the percentages of individuals with an active replication of HIV-1, HCV or both. During a one year follow-up of these patients at different stages of disease, blood samples were regularly collected for determination of transaminase, beta 2 microglobulin and CD4+ lymphocytes. Total RNAs were extracted from the sera, retrotranscribed with MoMuLV reverse transcriptase and nested PCR assays were carried out separately with sets of primers homologous to the 5' non-translated region of HCV and in HIV-1 gag. The amplified products were subjected to electrophoresis and observed under u.v. illumination after staining with ethidium bromide. For some samples, the identity of the amplified products was confirmed by Southern blotting by hybridization with enzyme-labelled probes. A total of 57% of the patients were found to produce HIV-1 RNA and 62% HCV RNA, while 34% produced both. HIV-1 RNA production was correlated with beta 2 microglobulin and CD4+ levels; active replication of HCV was correlated with hepatitis but not with CD4+ levels nor with HIV-1 RNA synthesis.

Base Sequence↗
PubMed1993

[A new threat: Xanthomonas maltophilia infection. Apropos of 50 cases].

In an attempt to further characterize infections due to Xanthomonas maltophilia (XM), we reviewed 50 case reports observed in our institution. XM is emerging as an important nosocomial pathogen in immunocompromised patients, especially those receiving broad spectrum antimicrobial antibiotherapy. Distinction between colonisation and infection is often difficult. XM presents a therapeutic challenge because of its tendency to exhibit multiple resistance.

Adult↗
PubMed1993

[Rheumatoid purpura in adults. Retrospective study of 38 patients].

The authors report retrospectively 38 cases of Schönlein-Henoch purpura (20 males, 18 females; median age, 26 years). Skin (37/38) and joint (21/38) manifestations are similar to those seen in children. Gastro intestinal (22/38) manifestations are less complicated. Long term outcome of the disease depends on kidney's involvement (32/38) and is severe: chronic renal failure in 31%.

Adult↗
PubMed1993

Human immunodeficiency virus type 1 replication within cystic lymphoepithelial lesion of the salivary gland.

Cystic lymphoepithelial lesions of salivary glands (CLLSG) are nodular or diffuse salivary gland enlargements that are observed in patients who tested positive for human immunodeficiency virus type 1 (HIV-1). Two cases of CLLSG are reported. Particular emphasis is placed on the presence of HIV-1 major-core protein (P24), HIV-1 RNA sequences, Epstein-Barr virus (EBV) DNA sequences, and lymphocyte receptor gene rearrangement. Lymphoid alterations consisted of explosive hyperplasia with a prominent follicular reticular dendritic cell (DRC) network and numerous intrafollicular CD8+ lymphocytes. Intrafollicular DRC strongly expressed HIV-1 major-core protein and HIV-1 RNA, indicating that most DRCs actively replicated the HIV-1 virus. The presence of active HIV-1 replication within DRC and the absence of clonal EBV infected lymphoid population strongly suggest that CLLSG pathogenesis is primarily induced by HIV-1. The presence of oligoclonal immunoglobulin gene rearrangements in our cases, however, suggest the need of long-term follow-up of such patients to determine whether CLLSG could be a benign prelymphomatous disease.

Adult↗
PubMed1993

Carcinoid heart disease: two cases of left heart involvement diagnosed by transthoracic and transoesophageal echocardiography.

We report two observations of significant left heart involvement in patients with the carcinoid syndrome assessed by transthoracic and transoesophageal echocardiography. Echocardiographic lesions of this kind have only been reported twice. In the present cases, there was mitral involvement with mitral regurgitation in one case and a mitro-aortic involvement with mitral and aortic regurgitation in the other. The mechanism of left heart lesions is unclear since in both cases no right-to-left cardiac shunt was present, as attested by colour Doppler and saline contrast transoesophageal echocardiography. The location of the primary tumour was unknown in one case and ileal in the other; no pulmonary metastasis was detected. The use of transoesophageal echocardiography might make it possible to detect left-sided cardiac lesions more frequently since they were found in anatomical series, in 30% of patients with carcinoid syndrome.

Aged↗
PubMed1993

Protein secondary structure prediction using two-level case-based reasoning.

We have developed a two-level case-based reasoning architecture for predicting protein secondary structure. The central idea is to break the problem into two levels: first, reasoning at the object (protein) level, and using the global information from this level to focus on a more restricted problem space; second, decomposing objects into pieces (segments), and reasoning at the internal structures level; finally, synthesizing the pieces back to the objects. The architecture has been implemented and tested on a commonly used data set with 69.3% predictive accuracy. It was then tested on a new data set with 67.3% accuracy. Additional experiments were conducted to determine the effects of using different similarity matrices.

Amino Acid Sequence↗
PubMed1992

[Syndrome of macrophagic activation with hemophagocytosis in human immunodeficiency virus infection].

The authors report two cases of hematophagic histiocytosis in HIV positive patients. In the first case, a patient with Kaposi sarcoma and Mycobacterium avium infection had a rapidly deteriorating course with progressive pancytopenia and death, as generally described in the literature. In the second case, hematophagic histiocytosis appeared during HIV primo infection and reversed spontaneously. Although few cases of hemophagocytic syndrome have been reported in HIV positive patient, it could represent an underestimated cause of pancytopenia. Both opportunistic microorganisms and HIV are able to cause hematophagic histiocytosis.

Adult↗
PubMed1990

In vitro activities of vancomycin and teicoplanin against coagulase-negative staphylococci isolated from neutropenic patients.

This study reports the in vitro activities of vancomycin and teicoplanin against 185 coagulase-negative staphylococcal strains isolated from 80 neutropenic patients who received different antibiotic treatments. All strains were susceptible to vancomycin: MICs for 50 and 90% of strains tested were 2 and 4 mg/liter, respectively. Teicoplanin was less active, and MICs displayed a wider range. For only teicoplanin was there a correlation between resistance and previous treatment. At the 4- and 32-mg/liter breakpoint levels, only 20% of the strains isolated from patients without glycopeptide treatment were intermediate or resistant, whereas 49.2% of the strains from patients who had received vancomycin or teicoplanin or both were intermediate or resistant.

Agranulocytosis↗
PubMed1988

[Randomized prospective study of ceftazidime versus a cefotaxime-tobramycin combination in acute leukemia in therapeutic aplasia].

In a prospective study, 157 patients with prolonged aplasia (PMN less than 500/mm3 during more than 21 days), hospitalized in a protected environment unit, were randomly assigned to receive ceftazidime alone or cefotaxime + tobramycin for initial febrile episodes. Age, sex, underlying diseases, duration of neutropenia, digestive decontamination regimen, clinical and microbiological characteristics of infections were similar in the two groups. Patients were evaluated for their initial response to antibiotics (defervescence in 48 hours, maintained 7 days) and long term response (prevention of another infection during aplasia). The overall initial response to ceftazidime was 48/71 (68 per cent) and to cefotaxime + tobramycin 55/86 (64 per cent). The long term response to ceftazidime was 33/71 (46.5 per cent) and to cefotaxime + tobramycin 31/86 (36 per cent). In conclusion, ceftazidime alone was as effective as cefotaxime + tobramycin in the first line treatment of febrile episodes in neutropenic patients.

Adolescent↗
PubMed1987

Hepatic perfusion index in cirrhotic livers--investigation of imaging and analytical procedures.

Dynamic hepatic scintigraphy was performed in a group of cirrhotic patients to evaluate the optimum imaging and analytical procedures necessary for the measurement of the hepatic perfusion index (HPI). Patients were studied in the posterior (n = 19) and the anterior (n = 14), positions, with either 0.2 or 0.5 ml of 99Tcm sulphur colloid administered as a rapid bolus injection. In each subject, three ROIs (small, medium and large) were drawn over the liver, and time-activity perfusion curves were generated. Analytical techniques were developed to allow flexibility in selecting the arterial and portal venous phases of the liver perfusion curve. The quality of the bolus, expressed as the full width at half-maximum of the left ventricular time--activity curve, was independent of the bolus volumes and patient positioning. The dispersion in the data and the inter-observer variation were less in the anterior view using medium and large ROIs, compared with the anterior small ROI and all the posterior ROI sizes. A time delay between liver and kidney arterial phases, if ignored, produced statistically significant effects on the values of the HPI. We conclude that HPI investigations are best performed in the anterior projection. Data analysis using a large liver ROI is preferred, and flexible data-processing techniques are recommended, particularly in the presence of a liver and kidney arterial time delay.

Adult↗
PubMed1987

Uncompacted lamellae in three patients with POEMS syndrome.

Three patients with POEMS syndrome were studied: two of them had myeloma, whereas the third had M protein without myeloma. Peripheral nerve biopsies showed no deposits of anti-Ig sera at direct immunopathological examination. Ultrastructural study revealed myelino-axonal degeneration in all three cases. This was associated in the first case with a dramatic loss of myelinated fibers and there were lesions consistent with acute degeneration in the second case. In addition, all three had some fibers showing uncompacted myelin lamellae. This peculiar modification has previously been reported only in cases of dysglobulinemia, lymphoma and inflammatory demyelinating polyneuropathy, but its mode of formation remains unclear.

Aged↗