Characterization of Haemophilus influenzae type b fimbriae.

We confirmed that the fimbriae of Haemophilus influenzae type b conferred hemagglutinating activity (HA) towards human erythrocytes, and erythrocytes of certain other species. Most (17/25) cerebrospinal fluid isolates lacked detectable HA on direct testing, but selective enrichment for fimbriation (f+) indicated that 22 of 25 strains could produce these surface structures. HA was unchanged from pH 4.5 to 9.5 and was not inhibited by mannose or certain other simple sugars. The HA titer of a suspension of three f+ strains was slightly decreased at 50 degrees C; HA was lost by heating at 60 degrees C for 3 min. Growth on a variety of solid and liquid media and under differing degrees of oxygenation did not change the HA titer of a suspension of three f+ strains. Fimbriation was not lost on repeated subculture. Wild-type fimbriated strains, and those derived by transformation, did not contain detectable plasmid DNA. Transformation of a strain lacking fimbriae to f+ was associated with the appearance of an outer membrane protein of 24 kilodaltons. This protein was purified from one strain to homogeneity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis by selective detergent solubilization and ammonium sulfate fractionation. Colonization capacity was equivalent with an isogenic untypable strain lacking or possessing fimbriae. Fimbriae of type b H. influenzae possess characteristics similar to those structures on other gram-negative bacteria; their role in cell physiology or pathogenesis of invasive disease is unknown.     

Recently Graduated Medical Students Lack Exposure to and Comfort with Chronic Liver Diseases

Digestive Diseases and Sciences - The prevalence of chronic liver disease (CLD) is rising, but it remains unclear if medical school curricula are emphasizing CLD to reflect its growing...     

Non-Hodgkin lymphomas in pregnancy: Tackling therapeutic quandaries

Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) often present with systemic symptoms such as fatigue, shortness of breath and night sweats, mimicking pregnancy-related features which may result in delayed disease diagnosis. Furthermore, the wish to avoid investigational imaging, aiming to protect the fetus from radiation exposure, may lead to a further delay, which does not often result in significant changes in HL clinical nature and patient outcome. In contrast, a more aggressive behavior (i.e., advanced disease stage and reproductive organ involvement) of most NHL types diagnosed in pregnancy may require urgent therapeutic intervention to prevent disease progression.     

In vitro flow based systems to study platelet function and thrombus formation: Recommendations for standardization: Communication from the SSC on Biorheology of the ISTH

Experimental videomicroscopic in vitro assays of thrombus formation based on blood perfusion are instrumental in a wide range of basic studies in thrombosis, screening for hereditary or acquired plateletrelated pathologies, and assessing the effectiveness of novel anti‐platelet therapies. Here, we discuss application of the broadly used “in vitro thrombosis model”: a frequently used assay to study the formation of 3D aggregates under flow, which involves perfusing anticoagulated whole blood over fibrillar collagen in a flow geometry of rectangular cross‐section, such as glass microcapillaries or parallel‐plate flow chambers. Major advantaged of this assay are simplicity and ability to reproduce the four main stages of platelet thrombus formation, i.e. platelet tethering, adhesion, activation and aggregation under a wide range of hemodynamic conditions. On the other hand, these devices represent, at best, simple reductive models of thrombosis. We also describe how blood flow assays can be used to study various aspects of platelet function on adhesive proteins and discuss the relevance of such flow models. Finally, we propose recommendations for standardization related to the use of this assay that cover collagen source, coating methods, micropatterning, sample composition, anticoagulation, choice of flow device, hemodynamic conditions, quantification challenges, variability, pre‐analytical conditions and other issues.     

The role of the lymphatic system in subcutaneous absorption of macromolecules in the rat model.

The purpose of this study was to assess the contribution of lymphatics to the systemic bioavailability of macromolecules following SC administration in a rat model. The rat model included continuous lymph collection from the thoracic lymph duct and concurrent serial blood sampling from freely moving animals. A thoracic lymph duct-jugular vein shunt produced by an implanted connective cannula, and maintained during the recovery period, enabled superior rat survival and prevented lymphatic cannula occlusion. The SC absorption of three macromolecules (bovine insulin, bovine serum albumin, and recombinant human erythropoietin alpha) was assessed in comparison to the non-lymph cannulated control group. For all tested molecules, only minimal amounts (less than 3%) of the SC administered dose were detected in the collected lymph. In the rat model, following SC administration, the macromolecules were absorbed mainly through the blood capillaries with minimal contribution of the lymphatic system to systemic bioavailability. The relatively small elevation in the lymphatic concentration, which occurred in all molecules, may be attributed to the redistribution of the molecules from the blood to the interstitial fluid compartment. These findings are important since rodents are commonly used in preclinical evaluation of macromolecular drugs.     

Cefpodoxime proxetil compared with amoxicillin-clavulanate for the treatment of otitis media.

In a multicenter, randomized, investigator-blinded trial, patients were randomly selected to receive either cefpodoxime proxetil or amoxicillin-clavulanate potassium orally for the treatment of acute suppurative otitis media. Patients were seen before, during, and at the end of therapy, and 2 to 3 weeks after completion of therapy. A total of 229 patients, 153 receiving cefpodoxime and 76 receiving amoxicillin-clavulanate were entered into the study; all patients were examined to determine drug safety. A total of 146 patients, 98 in the cefpodoxime group and 48 in the amoxicillin-clavulanate group, completed the study and were examined to determine drug efficacy. End-of-therapy microbiologic eradication rates in assessable patients were 92% for cefpodoxime and 86% for amoxicillin-clavulanate (p = 0.14; 95% confidence interval (CI) on difference: -4.4%, 19.2%). End-of-therapy clinical response rates for assessable patients were as follows: cured, 68% for cefpodoxime and 65% for amoxicillin-clavulanate; improved, 24% for cefpodoxime and 23% for amoxicillin-clavulanate; and failed, 8% for cefpodoxime and 13% for amoxicillin-clavulanate (p = 0.57; 95% CI: -8.4%, 16.5%). Recurrence rates at long-term follow-up were 24% for cefpodoxime-treated patients and 25% for those given amoxicillin-clavulanate. Both drugs were well tolerated; 20.9% of those given cefpodoxime and 31.6% of amoxicillin-clavulanate-treated patients had drug-related adverse medical events (p = 0.102; 95% CI: -23.9%, 2.6%). Gastrointestinal complaints were the most frequently reported drug-related side effect in both groups: 11.8% of cefpodoxime-treated patients and 21.1% of those given amoxicillin-clavulanate (p = 0.076; 95% CI: -20.8%, 2.2%). Drug-related dermatologic side effects (e.g., diaper rash, pruritus, urticaria) were reported in 7.8% of cefpodoxime-treated patients and 14.5% of those who received amoxicillin-clavulanate (p = 0.160; 95% CI: -16.6%, 3.3%). Our findings suggest that clinical efficacy for cefpodoxime administered twice daily is equivalent to that of amoxicillin-clavulanate administered three times a day.     

Genetic diversity of penicillin G-resistant Neisseria meningitidis from Spain.

Genotypic and phenotypic diversity among 16 penicillin G-resistant (Penr) isolates of Neisseria meningitidis recovered from human blood or cerebrospinal fluid in Spain was compared with that among 12 penicillin-susceptible (Pens) isolates by the use of multilocus enzyme electrophoresis, serotyping, auxotroph testing in chemically defined media, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of penicillin-binding proteins (PBPs). Thirteen distinctive multilocus enzyme genotypes (electrophoretic types [ETs] ) were identified among the 28 isolates. There was slightly less genetic diversity among the eight ETs of Penr isolates (H = 0.385) than among the eight ETs of Pens isolates (H = 0.431). Cluster analysis demonstrated two distinctive complexes of ETs and one ET that was not closely related to either complex. The possibility of a singular clonal origin of penicillin G-resistant isolates was excluded by the observations that resistance occurred in isolates of each of the two distantly related complexes of ETs, that three of the four ETs represented by multiple isolates included both susceptible and resistant strains, and that serotypes and growth requirements were not associated with the resistance phenotype. The 28 isolates showed a relatively homogeneous pattern of four PBPs, with apparently reduced penicillin G binding by PBP 3 of the Penr isolates.     

Genetic and phenotypic diversity among ampicillin-resistant, non-beta-lactamase-producing, nontypeable Haemophilus influenzae isolates.

Levels of genotypic and phenotypic diversity among 23 ampicillin-resistant, non-beta-lactamase-producing (Ampr NBLP) isolates of serologically nontypeable Haemophilus influenzae recovered from the respiratory tract were determined by multilocus enzyme electrophoresis, auxotroph testing in chemically defined media, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of penicillin-binding proteins (PBPs). Twenty distinctive multilocus enzyme genotypes were identified, among which the average level of genetic diversity per locus was equivalent to that in the species as a whole. Hence, a single, recent origin for Ampr NBLP strains is excluded. Of the growth factors tested, a requirement for methionine was significantly associated with the Ampr NBLP phenotype. In contrast to the relative homogeneity of the PBP profiles of the ampicillin-susceptible strains tested (8 PBPs detected), the PBP profiles of the Ampr NBLP strains exhibited marked heterogeneity (5 to 10 PBPs detected). Care should be taken in interpreting changes in PBP profiles and in associating these profiles with resistance for species such as H. influenzae that demonstrate variability.     

Human figure drawings in the evaluation of severe adolescent suicidal behavior

OBJECTIVE: To evaluate the reliability of using certain indicators derived from human figure drawings to distinguish between suicidal and nonsuicidal adolescents. METHOD: Ninety consecutive admissions to an adolescent inpatient unit were assessed. Thirty-nine patients were admitted because of suicidal behavior and 51 for other reasons. All subjects were given the Human Figure Drawing (HFD) test. HFD was evaluated according to the method of Pfeffer and Richman, and the degree of suicidal behavior was rated by the Child Suicide Potential Scale. RESULTS: The internal reliability was satisfactory. HFD indicators correlated significantly with quantitative measures of suicidal behavior; of these indicators specifically, overall impression of the evaluator enabled the prediction of suicidal behavior and the distinction between suicidal and nonsuicidal inpatients (p < .001). A group of graphic indicators derived from a discriminant analysis formed a function, which was able to identify 84.6% of the suicidal and 76.6% of the nonsuicidal adolescents correctly. Many of the items had a regressive quality. CONCLUSIONS: The HFD is an example of a simple projective test that may have empirical reliability. It may be useful for the assessment of severe suicidal behavior in adolescents.