Impact of HIV infection on meningitis in Harare, Zimbabwe: a prospective study of 406 predominantly adult patients

OBJECTIVE: To determine the causative organisms and characteristics of patients presenting with features of meningitis. DESIGN: A prospective cross-sectional study. SETTING: Two tertiary university-affiliated hospitals in Harare, Zimbabwe. PATIENTS: Four-hundred and six patients clinically suspected to have meningitis. MAIN OUTCOME MEASURES: Causative organisms of meningitis; clinical and cerebrospinal fluid characteristics. RESULTS: Four-hundred and six predominantly adult (95% were aged > or = 18 years) patients were suspected to have meningitis. Of the 200 patients confirmed to have meningitis, 89 (45%) had cryptococcal meningitis (CM), 54 (27%) had mononuclear meningitis (MM), 31 (16%) had pyogenic meningitis (PM), 24 (12%) had tuberculous meningitis (TBM) and 2 (1%) had undefined meningitis. HIV seropositivity was 100% in CM, 83% in MM, 81% in PM and 88% in TBM patients. In-hospital mortality rate was 38.8% for CM, 34.9% for MM, 68% for PM and 66.7% for TBM. HIV seropositivity was 80% in the 206 patients not found to have meningitis. CONCLUSIONS: All patients suspected to have meningitis had a high HIV sero positivity irrespective of whether they were later confirmed to have meningitis or not. CM was the most common type of meningitis seen. In-hospital mortality was high irrespective of the cause of meningitis.     

The sporogony of Eimeria tenella

In the course of the sporogony of Eimeria tenella 7 stages were differentiated: stage of rounded sporont, stage of knob formation, first four-globe stage, pyramid-stage, second four-globe stage, stage of sporozoit differentiation, stage of complete sporulation.     

Aktuelle Empfehlungen zu Prüfung, Deklaration und Einsatz von Desinfektionsmitteln

Ohne Zusammenfassung     

Avoided valence transition in a plutonium superconductor

The d and f electrons in correlated metals are often neither fully localized around their host nuclei nor fully itinerant. This localized/itinerant duality underlies the correlated electronic states of the high-T_c cuprate superconductors and the heavy-fermion intermetallics and is nowhere more apparent than in the 5f valence electrons of plutonium. Here, we report the full set of symmetry-resolved elastic moduli of PuCoGa₅—the highest T_c superconductor of the heavy fermions (T_c = 18.5 K)—and find that the bulk modulus softens anomalously over a wide range in temperature above T_c. The elastic symmetry channel in which this softening occurs is characteristic of a valence instability—therefore, we identify the elastic softening with fluctuations of the plutonium 5f mixed-valence state. These valence fluctuations disappear when the superconducting gap opens at T_c, suggesting that electrons near the Fermi surface play an essential role in the mixed-valence physics of this system and that PuCoGa₅ avoids a valence transition by entering the superconducting state. The lack of magnetism in PuCoGa₅ has made it difficult to reconcile with most other heavy-fermion superconductors, where superconductivity is generally believed to be mediated by magnetic fluctuations. Our observations suggest that valence fluctuations play a critical role in the unusually high T_c of PuCoGa₅.PuCoGa₅ enters the superconducting state below T_c = 18.5 K (1)—an order of magnitude higher than all Ce- or U-based superconductors. This contrast raises the question of whether PuCoGa₅ simply benefits from a higher superconducting-pairing energy scale than its U- and Ce-based relatives or instead, whether PuCoGa₅ is host to a completely different pairing mechanism. In many lanthanide and actinide compounds, the f electrons are nearly degenerate with the conduction band. In addition, the outer f-shell states are close in energy and may support two (or more) nearly degenerate valence configurations (2). In some cases, this valence degeneracy becomes unstable, leading to valence fluctuations and ultimately, a transition to a different valence state as a function of temperature, pressure, and/or doping (3). X-ray and photoemission spectroscopy (4, 5), neutron form factor measurements (6), and theoretical calculations (7) all indicate that PuCoGa₅ is in an intermediate valence state, with the 5f⁶ (Pu²⁺), 5f⁵ (Pu³⁺), and 5f⁴ (Pu⁴⁺) orbitals all residing near the chemical potential and all partially occupied. PuCoGa₅ exhibits no localized magnetic moments (6), and like other plutonium systems, its 5f electrons cannot be treated as fully localized or fully itinerant (4). [Strong Curie–Weiss-like magnetic susceptibility was initially reported for PuCoGa⁵, consistent with a local moment. However, additional susceptibility measurements (including polarized neutron scattering) have not reproduced this result (6).]In contrast, the analogous CeMIn₅ (M = Co, Rh, and Ir) series of superconductors has localized Ce 4f magnetic moments, with a tendency toward antiferromagnetic order (8). These systems reside close to an antiferromagnetic quantum critical point (9), where antiferromagnetic fluctuations are believed to mediate unconventional superconductivity. Because there is no evidence for PuCoGa₅ being in proximity to a magnetically ordered state (10), it is unlikely that magnetic fluctuations are the primary driver of its anomalously high T_c of 18.5 K (11). Valence fluctuations—where the total number of f electrons per ion fluctuates with the conduction band or the configuration of a fixed number of f electrons fluctuates between two or more nearly degenerate f states (sometimes known as orbital fluctuations)—have been proposed as a possible alternative mechanism for superconductivity in several heavy-fermion systems (12–15). Here, we report that PuCoGa₅’s elastic moduli soften over a large temperature range above T_c. Analysis of the observed temperature dependence of the softening, the symmetry channel in which it occurs, and its interplay with the superconducting transition suggests that valence fluctuations are critical for superconductivity in this system.     

Rehabilitation of ectodermal dysplasia patients presenting with hypodontia: outcomes of implant rehabilitation part 1

Purpose

This study has evaluated the pre and post perceptions of patients with ectodermal dysplasia (ED) who have been referred to Westmead Centre for Oral Health for treatment with dental implants.

Analysis of human hemopoietic progenitor cells for the expression of glycoprotein IIIa

Human hemopoietic progenitor cells were examined for the expression of glycoprotein IIIa (GPIIIa). This protein, which forms the beta-subunit of the GPIIb/IIIa receptor for cytoadhesive proteins as well as the beta-subunit of the vitronectin receptor, represents the most sensitive cell surface marker so far identified for the megakaryocytic lineage. Bone marrow cells were fractionated by a discontinuous Percoll gradient to separate cells that form megakaryocytic colonies in culture (1.05 greater than rho less than 1.077 g/ml). Density centrifugation was followed by indirect immunopanning to select for an enriched population of progenitor cells depleted of most of the mature cells of the myeloid, lymphoid, and erythroid lineages. This cell suspension was labeled with antibodies directed against determinants of GPIIIa and analyzed using a fluorescence-activated cell sorter (FACS). Fractions of cells were sorted and analyzed for the ability to form hemopoietic colonies in culture. Our study demonstrated that megakaryocytic progenitor cells (CFU-M) as well as granulocyte-macrophage colony-forming units (CFU-C), erythroid colony-forming units (BFU-E), and mixed lineage colony-forming units (CFU-GEMM) express HLA-DR antigens but lack GPIIIa. Therefore GPIIIa represents a marker that is not present on hemopoietic progenitor cells, but is expressed on the progenies of CFU-M. In view of the importance of GPIIIa as a component of receptors for cytoadhesive proteins, this finding may help to elucidate the adhesive interactions between early hemopoietic cells and bone marrow interstitium.