Biomedical subjects
L Baril
Publications and source records attributed to L Baril.
Pyogenic bacterial pneumonia in human immunodeficiency virus-infected inpatients: a clinical, radiological, microbiological, and epidemiological study.
We prospectively studied features of pyogenic bacterial pneumonia in 263 consecutive human immunodeficiency virus-infected inpatients over a 6-month study period. Risk factors for bacterial pneumonia were examined by a case-control study that included 33 cases who presented with at least one episode of bacterial pneumonia and 80 controls without bacterial pneumonia. The estimated cumulative incidence of bacterial pneumonia per year was 12.5 cases per 100 inpatients (95% confidence interval [CI], 8.8-17.2). The 38 episodes of bacterial pneumonia that occurred in the 33 inpatients were mainly unilateral, but 32 episodes were patchy lobar or diffuse infiltrates. Microbiological etiologies were obtained in 33 of the 38 episodes of bacterial pneumonia. Thirty-seven pathogens were identified, including Streptococcus pneumoniae (16, of which 12 had a decreased susceptibility to penicillin), Haemophilus influenzae (6), and Pseudomonas aeruginosa (6). The risk factors for bacterial pneumonia that were identified after logistic regression included prior sinusitis within 1 month before admission (odds ratio [OR], 3.2; 95% CI, 1.1-9.1) and prior bacterial infection of the lower respiratory tract within 6 months before admission (OR, 3.1; 95% CI, 1.1-8.3).
[Streptomyces somaliensis mycetoma with craniofacial involvement].
Mycetoma is a chronic granulomatous infection of the skin from which grains of the causative organism are eliminated via the sinus tracts. We report a rare case of cephalic mycetoma, which presented with an extensive involvement of the skull vault, base and an extradural granuloma. The diagnosis and treatment of the disease are discussed.
[Fat distribution anomalies and other metabolic disorders in patients under antiretroviral therapy].
MORPHOLOGY: Certain HIV-infected patients develop fat distribution anomalies 3 to 6 months after the introduction of antiretroviral therapy. Partial or generalized lipodystrophy can be observed, in the form of central obesity with accumulation of fat in the cervicoscapular, thoracic, abdominal or hip areas. The underlying mechanism remains unknown. METABOLISM DISORDERS: Elevated serum triglyceride, cholesterol, LDL-cholesterol, VLDL-cholesterol and glucose levels have been reported. Treatment of these metabolic anomalies remains a delicate challenge for patient management.
[Observance, adherence, compliance ...different words for better therapeutic results].
IMPROVING OBSERVANCE: For antiretroviral treatments including protease inhibitors, twice daily regimens have been tried instead of the t.i.d protocols. Available data are insufficient to determine the effect on observance. VERIFYING OBSERVANCE: Indinavir assays in the hair of treated patients have shown that the indinavir level is higher in responders than in non responders. BETTER UNDERSTANDING OF PRESCRIPTION MODALITIES: This can be a very useful tool in helping the patient understand his/her treatment and its duration.
Temperature, current, and magnetic-field dependence of the activation energy in the vortex-glass phase of (K,Ba)BiO3 single crystals.
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Flux motion and phase transitions in superconducting (K,Ba)BiO3 single crystals.
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Removal of soluble biologic response modifiers (complement and chemokines) by a bedside white cell-reduction filter.
BACKGROUND: Biologic response modifiers infused with stored platelet concentrates (PCs) are believed to contribute to symptoms seen during transfusion reactions. Although prestorage white cell reduction is known to decrease the production of some biologic response modifiers during storage, the possibility that poststorage (bedside) white cell reduction could reduce the amount of biologic response modifiers already present in stored PCs during bedside filtration has not been well studied. STUDY DESIGN AND METHODS: Individual PCs were pooled on storage Days 2 and 5 and passed through a third-generation white cell-reduction filter. The results from a series of in vitro PC assays were studied, before and immediately after filtration, as were levels of C3a and interleukin 8 (n = 5). Levels of other biologic response modifiers-C5a, interleukin 1 beta, interleukin 6, tumor necrosis factor alpha, and RANTES-were also studied. Removal of interleukin 8 and RANTES was studied further by using serial filtration of units of PC. RESULTS: For the in vitro platelet assays studied, pH was unchanged after filtration from prefiltration values in units of PCs pooled on storage Day 2 or 5. A 4 log10 reduction in white cells was reliably seen after filtration in Day 2 and 5 pooled PCs. Postfiltration platelet loss was 14.8 percent for Day 2 pooled PCs and 9.6 percent for Day 5 pooled PCs. For pools of both Day 2 and Day 5 platelets, postfiltration levels of CD62 (P-selectin, CD62P) were unchanged from prefiltration levels, as were results for morphology scores. Levels of C3a decreased after filtration in both the Day 2 pooled PCs (448 ng/mL before filtration vs. 20 ng/mL after filtration) and the Day 5 pooled PCs (1976 ng/mL before filtration vs. 124 ng/mL after filtration). Levels of interleukin 8 were similarly reduced after filtration in the Day 2 pooled platelets (188 pg/mL before filtration vs. 27 pg/mL after filtration) and the Day 5 pooled platelets (2234 pg/mL before filtration vs. 799 pg/mL after filtration). Levels of interleukin 8 in other components evaluated after filtration declined similarly. However, levels of the proinflammatory cytokines interleukin 1 beta and interleukin 6 did not decline after filtration. Serial filtration studies showed that, although levels of interleukin 8 and RANTES were initially lowered by filtration, they returned to prefiltration values with increases in the volume of filtration. CONCLUSION: The third-generation bedside filter used in this study reliably reduced the level of white cell contamination to 4 log10 white cells per PC. It also lowered the levels of interleukin 8, RANTES, and C3a. The filter did not, however, remove (scavenge) the proinflammatory cytokines interleukin 1 beta and 6. The mechanism of chemokine and C3a removal by the filter is unknown, but it may be related to ionic interactions between these biologic response modifiers and the filter medium.
Cytokine generation in stored, white cell-reduced, and bacterially contaminated units of red cells.
BACKGROUND: Proinflammatory cytokines were measured in the supernatant portion of stored, bacterially contaminated, and/or white cell (WBC)-reduced units of red cells (RBCs). Previous studies from this laboratory and others have shown that cytokines are generated in platelet concentrates during storage. This earlier work has been expanded to the study of stored RBCs. STUDY DESIGN AND METHODS: Units of AS-1 RBCs (n = 10 non-WBC-reduced; n = 10 WBC-reduced) were obtained from a regional blood center, and each was split on Day 3 of storage into three equal portions by sterile techniques. One portion was kept sterile (control), and the other two were inoculated with Yersinia enterocolitica and Staphylococcus aureus, respectively, at 1 to 3 colony-forming units per mL. The RBCs were stored at 1 to 6 degrees C for 42 days. Sequential samples were taken during storage and assayed for interleukin 8 (IL-8), interleukin 1 beta (IL-1 beta), interleukin 6, WBC count, and bacteria count. For the WBC-reduced group (n = 10), WBC removal was done by filtration on Day 3 of storage, before bacterial inoculation. RESULTS: IL-8 was detected in the supernatant portion of all 42-day-old, non-WBC-reduced (mean WBCs = 4760 +/- 3870/microL) units of AS-1 RBCs at levels ranging from 63 to 1610 pg per mL. By contrast, at 2 to 3 days of storage, lower levels of IL-8 (range, 0-280 pg/mL) were detected in the same units. IL-8 levels increased progressively during storage in most (7/10) units. The highest mean levels of IL-8 were reached by outdate at Day 42. Y. enterocolitica-contaminated units had statistically higher levels of IL-8, with a range of 170 to 2100 pg per mL, by 42 days of storage. S. aureus grew poorly in stored units of RBCs and failed to further stimulate cytokine production. No WBC-reduced unit (mean WBCs = 0.5 +/- 0.6/microL), even when contaminated with bacteria, had more than 260 pg per mL of IL-8. Although IL-1 beta was not detected in any unit of RBCs at 3 days of storage, it increased to low levels (5-13 pg/mL) in all units tested at 42 days. Interleukin 6 was not detected in any unit at any storage time. CONCLUSION: IL-8 and IL-1 beta accumulated in the supernatants of stored RBCs despite cold storage conditions. IL-8 reached levels > 1000 pg per mL in the supernatants of some RBC units. IL-1 beta increased to significant but low levels (< 13 pg/mL). WBC filtration early in storage prevented the accumulation of IL-8. The physiologic significance to transfusion recipients of IL-8 in RBC supernatants is currently unknown and deserves further investigation.
Tuberculosis caused by Mycobacterium africanum associated with involvement of the upper and lower respiratory tract, skin, and mucosa.
Cutaneous tuberculosis is rarely seen in industrialized countries and is usually caused by Mycobacterium tuberculosis. We report a case of cutaneous tuberculosis with bilateral nodular scleritis, nasal sinus invasion, and nasal septum perforation (confirmed by computed tomography scans of the sinuses), associated with pulmonary infiltrates and mediastinal adenopathy, in an African woman. Mycobacterium africanum was recovered from the sputum after 8 weeks of culture in Löwenstein-Jensen medium. To our knowledge, this is the first description of M. africanum associated with cutaneous tuberculosis and nasal sinus invasion.
Comparison of radioassay and microbiological assay for serum folate, with clinical assessment of discrepant results.
Folate assays by use of radiolabeled folate provide obvious practical advantages over the standard microbiological assay, but remain incompletely tested. We therefore compared results for 415 sera with a kit involving 3H-labeled folate and the Lactobacillus casei microbiological method. We examined the patients' data when there were discrepancies between the two methods. Although the correlation overall was satisfactory, results were discrepant in 25% of cases. In 74% of the latter, the radioassay result appeared to be the correct one, primarily because L. casei results were suppressed by antibiotics being taken by the patient. The radioassay occasionally gave falsely high values for patients with liver disease and falsely low ones for patients who had received isotopes for scanning purposes. Several assay kits that make use of 125I- or 75Se-labeled folate were also tested. Although these results correlated with the results of 3H-labeled folate assay, various problems appeared, including the possible need for serum-supernate control tubes in one kit. Answers to these and other questions and careful clinical correlation of results are needed for any folate radioassays before their adoption for routine clinical use.
Circulating immunoglobulin-transcobalamin I (R binder) complexes.
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Circulating antibody to transcobalamin II causing retention of vitamin B12 in the blood.
A patient with recurrent pulmonary abscess, weight loss, and alcoholism was found to have extremely high serum vitamin B12 and unsaturated vitamin B12-binding capacity (UBBC) levels. While transcobalamin (TC) II was also increased, most of his UBBC was due to an abnormal binding protein which carried greater than 80% of the endogenous vitamin B12 and was not found in his saliva, granulocytes, or urine. This protein was shown to be a complex of TC II and a circulating immunoglobulin (IgGkappa and IgGlambda). Each IgG molecule appeared to bind two TC II molecules. The reacting site did not interfere with the ability of TC II to bind vitamin B12, but did interfere with its ability to transfer the vitamin to cells in vitro. The site was not identical to that reacting with anti-human TC II antibody produced in rabbits. Because of this abnormal complex, 57Co-vitamin B12 injected intravenously was cleared slowly by the patient. However, no metabolic evidence for vitamin B12 deficiency was demonstrable, although the patient initially had megaloblastic anemia apparently due to folate deficiency. The course of the vitamin B12-binding abnormalities was followed over 4 yr and appeared to fluctuate with the status of the patient's illness. The IgG-TC II complex resembled one induced in some patients with pernicious anemia by intensive treatment with long-acting vitamin B12 preparations. The mechanism of induction of the antibody formation in our patient is unknown.
Removal of anaphylatoxins C3a and C5a and chemokines interleukin 8 and RANTES by polyester white cell-reduction and plasma filters.
BACKGROUND: A few bedside polyester white cell (WBC)-reduction filters have been shown to scavenge C3a anaphylatoxin from stored blood components. One has been shown to remove the chemokines interleukin (IL)-8 and RANTES, but not the proinflammatory cytokines IL-1, IL-6, and tumor necrosis factor alpha. Removal by any filter of the anaphylatoxin C5a or the soluble membrane attack complex (SC5b-9) has not been studied. Further, the ability of other filters to scavenge these biologic response modifiers (BRM) is not known. Four WBC-reduction filters and one plasma filter were studied for their ability to remove IL-8, RANTES, IL-1 beta, C3a, C5a, and SC5b-9. STUDY DESIGN AND METHODS: Plasma was obtained either as freshly thawed fresh-frozen plasma, fresh-frozen plasma thawed and stored for 5 days, or platelet-poor supernatant. Cell-poor plasma was obtained and samples were taken before and after filtration through the various filters Levels of IL-1 beta, IL-8, RANTES, C3a, and SC5b9 were quantitated by enzyme immunoassay. To evaluate filter scavenging of C5a, an in vitro model was developed to generate high levels of C5a in plasma by activating plasma with zymosan. RESULTS: Levels of C3a, C5a, IL-8, and RANTES were reduced by filtration through two bedside platelet WBC-reduction filters, a plasma filter, and a prestorage red cell WBC-reduction filter, but not following filtration through a prestorage platelet WBC-reduction filter. For some BRMs and filters, however, evidence of filter saturation was seen. IL-1 beta was not removed by any of the filters tested. CONCLUSION: Some, but not all, bedside polyester filters and prestorage polyester filters can remove IL-8, RANTES, C3a, and C5a from units of plasma or platelets. Improved biomaterial engineering of these and other filters could maximize scavenging of BRMs and potentially diminish the adverse reactions associated with their infusion during transfusion.
Persistence of antineutrophil cytoplasmic antibodies (ANCA) in asymptomatic patients with systemic polyarteritis nodosa or Churg-Strauss syndrome: follow-up of 53 patients.
OBJECTIVE: We retrospectively analyzed the significance of persistent ANCA positivity after clinical remission in 53 consecutive patients with histologically and/or angiographically proven polyarteritis nodosa (PAN), or Churg-Strauss syndrome (CSS) followed between 1981 and 1993. METHODS: ANCA were detected using an immunofluorescence assay and ELISA: Each patient met the American College of Rheumatology 1990 criteria for PAN or CSS. Clinical and biological evaluations were always essential factors in the decision to intensify therapy. RESULTS: ANCA were initially present in 15 patients (28.3%): 3/26 (11.5%) with HBV-related PAN, 6/18 (33.3%) with PAN of unknown etiology and 6/9 (66.7%) with CSS. Five patients remained ANCA-positive after clinical remission: 3 with PAN (one of them relapsed) and 2 with CSS who both relapsed. Among the 12 patients who died during follow-up, only 1 (8.3%) was initially ANCA-positive. Fifteen of the 41 survivors (29.2%) were ANCA-positive. CONCLUSION: Persistence of ANCA positivity in PAN and CSS may be a marker of an underlying disease process, but does not adequately reflect disease activity and, thus, in no case should be the only indication for therapeutic intensification.