Plasmodium falciparum sexual parasites develop in human erythroblasts and affect erythropoiesis

Plasmodium falciparum gametocytes, the sexual stage responsible for malaria parasite transmission from humans to mosquitoes, are key targets for malaria elimination. Immature gametocytes develop in the human bone marrow parenchyma, where they accumulate around erythroblastic islands. Notably though, the interactions between gametocytes and this hematopoietic niche have not been investigated. Here, we identify late erythroblasts as a new host cell for P falciparum sexual stages and show that gametocytes can fully develop inside these nucleated cells in vitro and in vivo, leading to infectious mature gametocytes within reticulocytes. Strikingly, we found that infection of erythroblasts by gametocytes and parasite-derived extracellular vesicles delay erythroid differentiation, thereby allowing gametocyte maturation to coincide with the release of their host cell from the bone marrow. Taken together, our findings highlight new mechanisms that are pivotal for the maintenance of immature gametocytes in the bone marrow and provide further insights on how Plasmodium parasites interfere with erythropoiesis and contribute to anemia in malaria patients.

An Algorithm for the Rational Choice of Sodium Profile during Hemodialysis

The incidence of intradialytic disequilibrium syndrome and symptomatic hypotension has increased significantly among dialysis patients over the last ten years. Profiled hemodialysis (PHD) is a new technique, based on the intradialytic modulation of dialysate sodium concentration, which aspires to reduce to previous imbalances.

This paper presents a new algorithm for the determination of a rational dialysate sodium profile during PHD. A mathematical model of solute kinetics, monocompartmental for sodium and bicompartmental for urea is used. The algorithm allows the sodium profile to be elaborated a priori before each dialysis session, respecting the individual sodium mass removal and weight gain. A procedure allowing the adjustment of the method to the individual characteristics, on the basis of routine measurements performed before each session is also presented.

The method was validated during seven dialysis sessions. Comparison between data measured in vivo and those predicted by the model showed standard deviations corresponding to the range of laboratory measurement errors: 1.50 mEq/L for sodium and 0.87 mmol/L for urea. In vivo implementation of PHD by our algorithm allows one to remove an amount of sodium close to that established a priori on the basis of patient's need.

Constraints on an annihilation signal from a core of constant dark matter density around the milky way center with H.E.S.S

An annihilation signal of dark matter is searched for from the central region of the Milky Way. Data acquired in dedicated on-off observations of the Galactic center region with H.E.S.S. are analyzed for this purpose. No significant signal is found in a total of ∼9  h of on-off observations. Upper limits on the velocity averaged cross section, ⟨σv⟩, for the annihilation of dark matter particles with masses in the range of ∼300  GeV to ∼10  TeV are derived. In contrast to previous constraints derived from observations of the Galactic center region, the constraints that are derived here apply also under the assumption of a central core of constant dark matter density around the center of the Galaxy. Values of ⟨σv⟩ that are larger than 3×10^{-24}  cm^{3}/s are excluded for dark matter particles with masses between ∼1 and ∼4  TeV at 95% C.L. if the radius of the central dark matter density core does not exceed 500 pc. This is the strongest constraint that is derived on ⟨σv⟩ for annihilating TeV mass dark matter without the assumption of a centrally cusped dark matter density distribution in the search region.

Effects of consumption of whole grain foods rich in lignans in healthy postmenopausal women with moderate serum cholesterol: a pilot study

This study aims at investigating the effect of an experimental period of intake of whole grain foods rich in lignans as part of an habitual diet on the plasma and urinary excretion of enterolignans, the biomarkers of lipid metabolism and the immunological and antioxidant status in a group of postmenopausal women with moderate serum cholesterol. A randomized double-blind crossover study was completed on 13 subjects in 12-weeks after protocol approval of an ethical committee. The subjects consumed whole grain foods high in lignans (30 g/d of breakfast cereals or biscuits, etc., 80 g/d of whole grain pasta) or refined grain foods for 4 weeks, separated by a 2-weeks wash-out period. A modest hypocholesterolemic effect (p < 0.05) of the whole grain diet was observed and the intake of whole grain products rich in lignans was also associated with an increase in urinary enterodiol excretion (p < 0.05).

Search for photon-linelike signatures from dark matter annihilations with H.E.S.S

Gamma-ray line signatures can be expected in the very-high-energy (E(γ)>100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical γ-ray sources that in most cases produce continuous spectra that span over several orders of magnitude in energy. Using data collected with the H.E.S.S. γ-ray instrument, upper limits on linelike emission are obtained in the energy range between ∼ 500 GeV and ∼ 25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. No statistically significant signal could be found. For monochromatic γ-ray line emission, flux limits of (2 × 10(-7) -2 × 10(-5)) m(-2) s(-1) sr(-1) and (1 × 10(-8) -2 × 10(-6)) m(-2) s(-1)sr(-1) are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. For a DM particle mass of 1 TeV, limits on the velocity-averaged DM annihilation cross section ⟨σv⟩(χχ → γγ) reach ∼ 10(-27) cm(3)s(-1), based on the Einasto parametrization of the Galactic DM halo density profile.

Oblique electron-cyclotron-emission radial and phase detector of rotating magnetic islands applied to alignment and modulation of electron-cyclotron-current-drive for neoclassical tearing mode stabilization

A two channel oblique electron cyclotron emission (ECE) radiometer was installed on the DIII-D tokamak and interfaced to four gyrotrons. Oblique ECE was used to toroidally and radially localize rotating magnetic islands and so assist their electron cyclotron current drive (ECCD) stabilization. In particular, after manipulations operated by the interfacing analogue circuit, the oblique ECE signals directly modulated the current drive in synch with the island rotation and in phase with the island O-point, for a more efficient stabilization. Apart from the different toroidal location, the diagnostic view is identical to the ECCD launch direction, which greatly simplified the real-time use of the signals. In fact, a simple toroidal extrapolation was sufficient to lock the modulation to the O-point phase. This was accomplished by a specially designed phase shifter of nearly flat response over the 1-7 kHz range. Moreover, correlation analysis of two channels slightly above and below the ECCD frequency allowed checking the radial alignment to the island, based on the fact that for satisfactory alignment the two signals are out of phase.

Search for a dark matter annihilation signal from the galactic center halo with H.E.S.S

A search for a very-high-energy (VHE; ≥100  GeV) γ-ray signal from self-annihilating particle dark matter (DM) is performed towards a region of projected distance r∼45-150  pc from the Galactic center. The background-subtracted γ-ray spectrum measured with the High Energy Stereoscopic System (H.E.S.S.) γ-ray instrument in the energy range between 300 GeV and 30 TeV shows no hint of a residual γ-ray flux. Assuming conventional Navarro-Frenk-White and Einasto density profiles, limits are derived on the velocity-weighted annihilation cross section (σv) as a function of the DM particle mass. These are among the best reported so far for this energy range and in particular differ only little between the chosen density profile parametrizations. In particular, for the DM particle mass of ∼1  TeV, values for (σv) above 3×10(-25)  cm(3) s(-1) are excluded for the Einasto density profile.

Energy spectrum of cosmic-ray electrons at TeV energies

The very large collection area of ground-based gamma-ray telescopes gives them a substantial advantage over balloon or satellite based instruments in the detection of very-high-energy (>600 GeV) cosmic-ray electrons. Here we present the electron spectrum derived from data taken with the High Energy Stereoscopic System (H.E.S.S.) of imaging atmospheric Cherenkov telescopes. In this measurement, the first of this type, we are able to extend the measurement of the electron spectrum beyond the range accessible to direct measurements. We find evidence for a substantial steepening in the energy spectrum above 600 GeV compared to lower energies.

Limits on an energy dependence of the speed of light from a flare of the active galaxy PKS 2155-304

In the past few decades, several models have predicted an energy dependence of the speed of light in the context of quantum gravity. For cosmological sources such as active galaxies, this minuscule effect can add up to measurable photon-energy dependent time lags. In this Letter a search for such time lags during the High Energy Stereoscopic System observations of the exceptional very high energy flare of the active galaxy PKS 2155-304 on 28 July 2006 is presented. Since no significant time lag is found, lower limits on the energy scale of speed of light modifications are derived.

Evolution of the millimeter-wave collective Thomson scattering system of the high-field tokamak Frascati Tokamak Upgrade

We first describe the improved receiving system of the diagnostic experiment of millimeter-wave collective Thomson scattering being run on the Frascati Tokamak Upgrade (FTU), and then discuss some peculiar problems and new operating procedures related to the investigation of strong anomalous spectra of nonthermal origin, many-orders-of-magnitude stronger than the ion thermal feature merged in them, systematically observed in the experimentation, and finally ascribed to a perturbation of the gyrotron that generates the probing beam. Arguments in favor of a more general valence of the solutions actuated for the specific case of FTU are finally given.

Complex chimeras to map ligand binding sites of GPCRs

Family 1a GPCRs are thought to bind small molecule ligands in a pocket comprising sequences from non-contiguous transmembrane helices. In this study, receptor-ligand binding determinants were defined by building a series of complex chimeras where multiple sequences were exchanged between related G-protein coupled receptors. Regions of P2Y(1), P2Y(2) and BLT(1) predicted to interact with nucleotide and leukotriene ligands were identified and receptors were engineered within their transmembrane helices to transpose the ligand binding site of one receptor on to another receptor. Ligand-induced activation of chimeras was compared with wild-type receptor activation in a yeast reporter gene assay. Binding of ligand to a P2Y(2)/BLT(1) chimera confirmed that the ligand binding determinants of BLT(1) are located in the upper regions of the helices and extracellular loops of this receptor and that they had been successfully transferred to a receptor that normally binds unrelated ligands.

Electron-Bernstein-wave current drive in an overdense plasma at the Wendelstein 7-AS stellarator

Electron-Bernstein-wave (EBW) current drive in an overdense plasma was demonstrated at the Wendelstein 7-AS stellarator for the first time. The EBWs were generated by O-X-B mode conversion. The relatively high current drive efficiency was consistent with theoretical predictions. The experiments provided first investigations of EBW phase space interaction for wave refractive indices much larger than unity.

Tollip, a new component of the IL-1RI pathway, links IRAK to the IL-1 receptor

Interleukin-1 (IL-1) is a proinflammatory cytokine that elicits its pleiotropic effects through activation of the transcription factors NF-kappaB and AP-1. Binding of IL-1 to its receptor results in rapid assembly of a membrane-proximal signalling complex that consists of two different receptor chains (IL-1Rs), IL-1RI and IL-1RAcP, the adaptor protein MyD88, the serine/threonine kinase IRAK and a new protein, which we have named Tollip. Here we show that, before IL-1beta treatment, Tollip is present in a complex with IRAK, and that recruitment of Tollip-IRAK complexes to the activated receptor complex occurs through association of Tollip with IL-1RAcP. Co-recruited MyD88 then triggers IRAK autophosphorylation, which in turn leads to rapid dissociation of IRAK from Tollip (and IL-1Rs). As overexpression of Tollip results in impaired NF-kappaB activation, we conclude that Tollip is an important constituent of the IL-1R signalling pathway.

Overexpression of an enzymically inactive interleukin-1-receptor-associated kinase activates nuclear factor-kappaB

Upon interleukin 1 (IL-1) stimulation, the IL-1-receptor (IL-1R)-associated kinase (IRAK) is rapidly recruited to the IL-1R complex and undergoes phosphorylation. Here we demonstrate that recombinant wild-type IRAK (IRAK-WT), but not a kinase-defective mutant with Asp340 replaced by an asparagine residue (IRAK-Asp340Asn), is highly phosphorylated and is capable of auto-phosphorylation in vitro. Overexpression of both IRAK-WT and IRAK-Asp340Asn caused activation of nuclear factor kappaB, suggesting that the kinase activity of IRAK is not required outside of the IL-1R complex.

A simple mathematical model applied to selection of the sodium profile during profiled haemodialysis

BACKGROUND

Among dialysis patients in the last 10 years the incidence of intradialytic dysequilibrium syndrome and symptomatic hypotension has increased significantly. Profiled haemodialysis (PHD), a new dialysis technique based on intradialytic modulation of the dialysate sodium concentration according to pre-elaborated individual profiles, has been set up to reduce intradialytic imbalances and the incidence of dysequilibrium syndrome and symptomatic hypotension. The present paper illustrates a new mathematical model for solute kinetics, single-compartment for sodium and two-compartment for urea, aimed at improving the use of PHD. The model allows the sodium profile to be elaborated a priori, before each dialysis session, according to the patient's clinical needs and respecting the individual sodium mass removal and weight gain.

METHOD

The mathematical model was first derived and then applied to determining a rational dialysate sodium profile. A procedure which allows the method to be tuned to individual clinical needs on the basis of routine measurements performed before each session is also presented. The proposed method was validated in vivo during seven dialysis sessions, each performed on a different patient.

RESULTS

The comparison between data predicted by the model and those obtained in vivo shows a good correspondence in particular concerning the time pattern of blood urea and sodium. The comparison between the model prediction and in vivo determined sodium and urea plasma curves showed standard deviations (2.25 mEq/l for sodium and 0.87 mmol/l for urea) only slightly higher than those attributable to laboratory measurement errors. Moreover, in vivo implementation of PHD by our model enables one to remove an amount of sodium mass comparable with the a priori quantity predicted by the model.

The IL1 receptor accessory protein is responsible for the recruitment of the interleukin-1 receptor associated kinase to the IL1/IL1 receptor I complex

Following interleukin-1 (IL1) stimulation, an IL1 receptor associated kinase (IRAK) is rapidly recruited to the receptor complex. However, it is not understood if IRAK is able to interact directly with the intracellular portion of the IL1-RI or if its recruitment is mediated by a different molecule. Using the yeast two-hybrid system, we have analysed possible protein-protein interactions between IRAK, IL1-RI and IL1-RAcP. We found that IRAK is able to interact with the equivalent cytoplasmic region of the IL1-RAcP but is unable to interact with the cytoplasmic region of the IL1-RI. Immunoprecipitation of the IL1-RAcP followed by Western blot analysis using anti-IRAK antibodies revealed that IRAK co-precipitated with the IL1-RAcP. We propose that, in non-stimulated cells, IRAK is bound to the IL1-RAcP and therefore, following IL1 stimulation, both molecules are recruited simultaneously to the ILI-RI complex.

An algorithm for the rational choice of sodium profile during hemodialysis

The incidence of intradialytic disequilibrium syndrome and symptomatic hypotension has increased significantly among dialysis patients over the last ten years. Profiled hemodialysis (PHD) is a new technique, based on the intradialytic modulation of dialysate sodium concentration, which aspires to reduce to previous imbalances. This paper presents a new algorithm for the determination of a rational dialysate sodium profile during PHD. A mathematical model of solute kinetics, monocompartmental for sodium and bicompartmental for urea is used. The algorithm allows the sodium profile to be elaborated a priori before each dialysis session, respecting the individual sodium mass removal and weight gain. A procedure allowing the adjustment of the method to the individual characteristics, on the basis of routine measurements performed before each session is also presented. The method was validated during seven dialysis sessions. Comparison between data measured in vivo and those predicted by the model showed standard deviations corresponding to the range of laboratory measurement errors: 1.50 mEq/L for sodium and 0.87 mmol/L for urea. In vivo implementation of PHD by our algorithm allows one to remove an amount of sodium close to that established a priori on the basis of patient's need.

Isolation and molecular characterization of the bifunctional hydroxymethyldihydropterin pyrophosphokinase-dihydropteroate synthase gene from Toxoplasma gondii

Toxoplasma gondii is an important cause of AIDS-related opportunistic infection, manifest as toxoplasmic encephalitis. The clinical treatment of choice is the synergistic combination of antifolate agents, pyrimethamine and sulphadiazine, of which the latter targets the parasite's dihydropteroate synthase (DHPS) activity. Here, we describe the isolation of the gene encoding this activity in T. gondii. The nucleotide sequence contains an open reading frame interrupted by five introns, which encodes a protein of 664 amino acids with an M(r) of 72991. Sequence analysis revealed that, in addition to DHPS, the predicted protein contains a second enzyme function, hydroxymethyldihydropterin pyrophosphokinase (PPPK). This enzyme immediately precedes DHPS in the folate biosynthetic pathway. The bifunctional arrangement of the T. gondii pppk-dhps gene is the same as that observed in the related protozoan parasite, Plasmodium falciparum, and confirms previous biochemical data that these activities were inseparable. Recently, specific mutations within conserved motifs of the DHPS gene of P. falciparum have been identified which give rise to sulphonamide drug resistance. Analysis of seven clinical isolates of T. gondii did not reveal any similar mutations in this limited sample of organisms that had been subjected to drug pressure.

[Congenital granular-cell epulis. A histochemical case study]

Following a review of the literature the author reports the various different hypotheses regarding the origin and nature of congenital epulis, a pedunculated neoformation with a gingival or more rarely mandibular localisation. Epulides present dimensions varying from a few millimetres to a couple of centimetres and they may exceptionally be multiple in the same subject. A case of granulocellular congenital epulis is reported covered by integral mucosa, located in correspondence with the maximally gingiva in a paramedical site. The epulis, removed a few days after birth since it prevented the child from sucking, did not present any other pathological element and underwent optical microscope examination using hematoxylin staining, eosin, PAS, argentic impregnation according to Gomori, Masson's Trichromic, Alcian Bleu. The results are discussed in relation to the histogenesis of this rare gingival lesion: the histogenetic question is still unresolved given that even the ultrastructural tests performed by various authors have yielded discordant results. The hypothesis of an hamartomatous nature of the epulis is however more plausible than the hypothesis of a neoplastic process in the strict sense of the term.

[Globulomaxillary cysts]

Globulomaxillary cyst is a non odontogenic cyst arising in the upper lateral incisor and canine region. Evaluation of clinical picture and careful histologic examination are essential for distinguishing it from other odontogenic and non odontogenic cystic growths. Presenting five new cases of globulomaxillary cysts, authors discuss and accept the "fissural" histogenetic hypothesis.

Molecular characterization and localization of human metabotropic glutamate receptor type 3

A human brain cDNA library was screened using amplified human metabotropic glutamate receptor (mGluR) cDNA sequences as probes. The resulting clones included one containing the complete coding sequence of mGluR3. This sequence has 90% DNA sequence identity with rat mGluR3 and the predicted protein sequence has 97% identity. The mGluR3 cDNA was transfected in Chinese hamster ovary (CHO) cells. Stimulation of the expressed receptor by (2S,3S,4S)-alpha-(carboxycyclopropyl) glycine (L-CCG-I) resulted in a reduction of forskolin-stimulated cyclic AMP (cAMP) with EC50 values of 0.15-0.3 microM. A specific probe from the human mGluR3 clone was used to hybridise to Northern blots of mRNA from various human tissues and different brain regions. The mGluR3 mRNA is brain-specific, and is expressed in all the brain regions represented on the blot. In-situ hybridization studies on human brain sections confirmed this widespread distribution with expression in neurones in the cerebral cortex, caudate-putamen, thalamus and cerebellum.

Two domains with amino-acid sequence similarity are required for dihydroneopterin aldolase function in the multifunctional folic acid synthesis Fas protein of Pneumocystis carinii

The folic acid synthesized gene (fas) of Pneumocystis carinii (Pc) codes for a multifunctional enzyme (Fas) known to catalyse three consecutive steps leading to the production of dihydropteroate in the de novo folate synthesis pathway. Previously, we predicted that a domain, designated FasB (amino acids (aa) 161-280), of the 740-aa multifunctional protein contains the first of the three enzyme activities in the pathway, namely dihydroneopterin aldolase (DHNA), since it shares 23% aa identity with the DHNA of Streptococcus pneumoniae (Sp). We now extend these findings to show that a second domain, FasA (aa 39-160), whose function was previously unknown, shares 27% sequence identity with the adjacent FasB domain, indicative of functional similarity. FasA is also 18% identical with the DHNA from Sp. Recombinant baculoviruses were constructed which directed the production of either FasA, FasB or FasAB polypeptide species in cultured Spodoptera frugiperda (SF9) insect cells. No DHNA activity is associated with either fasA or fasB when produced as single domains in the insect-baculovirus system. However, DHNA activity was detected in SF9 extracts containing the overproduced FasAB polypeptide. The results of aa sequence alignments and expression studies suggest that FasA and FasB may be two subunits of the DHNA enzyme moiety within the multifunctional Fas protein of Pc. An alternative interpretation of the results is also discussed.

The hydroxymethyldihydropterin pyrophosphokinase domain of the multifunctional folic acid synthesis Fas protein of Pneumocystis carinii expressed as an independent enzyme in Escherichia coli: refolding and characterization of the recombinant enzyme

The folic acid synthesis (Fas) protein of Pneumocystis carinii is a multifunctional enzyme containing dihydroneopterin aldolase, 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (PPPK), and dihydropteroate synthase activities. Isolation of the stretch of fas cDNA shown by amino acid similarity to the bacterial counterparts to code for PPPK activity (fasC domain) is described. FasC was expressed to high levels in Escherichia coli inclusion bodies using an inducible tac promoter expression system. Solubilization of the inclusion bodies in 6 M guanidine hydrochloride and refolding of the recombinant protein yielded enzymatically active PPPK which was purified to homogeneity by anion-exchange and gel-filtration chromatography. Sequence analysis showed that the first 13 amino acids of the purified protein were in agreement with those predicted from the DNA sequence and, furthermore, that the amino-terminal methionine had been removed. The enzyme is active in the monomeric form, exhibiting maximum activity at around pH 8.0. Isoelectric focusing gave a pI of 9.1. The Km value for 6-hydroxymethyl-7,8-dihydropterin was 3.6 microM in 50 mM Tris buffer, pH 8.2. The production of independently folded, active P. carinii PPPK will allow detailed biochemical and structural studies, increasing our understanding of this enzyme domain.

The multifunctional folic acid synthesis fas gene of Pneumocystis carinii encodes dihydroneopterin aldolase, hydroxymethyldihydropterin pyrophosphokinase and dihydropteroate synthase

The nucleotide sequence of a folic acid synthesis (fas) gene from Pneumocystis carinii contains an open reading frame (ORF) that predicts a protein of 740 amino acids with an M(r) of 83,979. A recombinant baculovirus was constructed which directed expression of the predicted Fas740 polypeptide in cultured Spodoptera frugiperda (SF9) insect cells. The overexpressed 'full-length' protein migrated anomalously in sodium dodecyl sulfate/polyacrylamide gels, with an apparent molecular mass of 71.5 kDa. An abundant 69-kDa species was also recognized by polyclonal sera specific for the Fas protein in immunoblotting analyses. Dihydroneopterin aldolase, dihydropterin pyrophosphokinase and dihydropteroate synthase activities were readily detected in SF9 extracts in which the 71.5/69-kDa immunoreactive species were overproduced, demonstrating that three enzyme functions involved in catalysing three sequential steps of the folate biosynthetic pathway are encoded by a single gene in P. carinii. Importantly, the polyclonal sera recognize a single 69-kDa species in P. carinii extracts suggesting that the three activities are indeed properties of a single polypeptide, although the nature of the suggested post-translational modification is unknown. Location of the individual enzyme domains with the Fas polypeptide based upon amino acid sequence similarity to their bacterial counterparts is discussed. Furthermore, expression of various truncated fas gene constructs demonstrates that the complete fas ORF, including the N-terminus of the predicted polypeptide (FasA domain) whose enzyme function is unknown, must be expressed for maximum dihydroneopterin aldolase (FasB domain) and dihydropteroate synthase (FasD domain) activities. This suggests interactions between the domains within the larger polypeptide to stabilize the functions of these two enzymes. The FasC domain, which contains 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase activity, is able to fold and function independently of the other domains. The requirement by mammalian cells for preformed folates, and the absence of dihydroneopterin aldolase, 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase and dihydropteroate synthase from these tissues opens up the possibility of designing highly selective drugs which inhibit these unique targets.

[Compression of the sigmoid of gynecological origin]

The authors report a case of extrinsic stenosis of the sigmoid colon due to inflammation of the uterus and adjoining parts. Attention is drawn to the possibility that the radiological images of this condition may be similar to neoplastic diseases.

Cloning and sequence of a beta-tubulin cDNA from Pneumocystis carinii: possible implications for drug therapy

This work describes the isolation and characterization of a full-length cDNA clone encoding beta-tubulin from the pathogen Pneumocystis carinii. P. carinii contains a single gene encoding beta-tubulin. The complete sequence of this cDNA has been determined and its inferred amino acid sequence compared with the beta-tubulins from other organisms. This analysis augments the data indicating that P. carinii should be classified as a fungal organism. Further comparisons between the P. carinii beta-tubulin and those of fungal beta-tubulins resistant to benomyl, a beta-tubulin-binding drug, indicate a difference which may be exploited in the development of a new drug therapy for P. carinii pneumonitis. These results suggest that, theoretically, a drug presently administered for treatment of nematode worm infections may be an effective agent against P. carinii, without being toxic to the mammalian host. This possibility is currently being investigated.

The multifunctional folic acid synthesis fas gene of Pneumocystis carinii appears to encode dihydropteroate synthase and hydroxymethyldihydropterin pyrophosphokinase

We describe the cloning of a multifunctional folic acid synthesis (fas) gene from Pneumocystis carinii. The nucleotide sequence contains an open reading frame interrupted by three introns, that encodes a protein of 740 amino acids with an Mr of 97,278. The predicted Fas protein has homology to two enzyme domains, dihydropteroate synthase and 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase, both of which are involved in folate synthesis, and at least one other region of unknown function.

Oral manifestation of disseminated Mycobacterium avium intracellulare in a patient with AIDS

The acquired immune deficiency syndrome (AIDS) is characterized by a selective suppression of the immune system that renders patients susceptible to infection by a variety of opportunistic organisms. Among these is Mycobacterium avium intracellulare. AIDS victims often have oral manifestations of Kaposi's sarcoma and candidiasis. This article reports an unusual oral presentation of disseminated infection with Mycobacterium avium intracellulare in a patient with AIDS.

Quantitative determination of benzoyl peroxide by high-performance liquid chromatography and comparison to the iodometric method

A selective high-performance liquid chromatographic (HPLC) procedure for the quantitative determination of benzoyl peroxide in pharmaceutical dosage forms is described. Benzoyl peroxide was dissolved or extracted in the presence of an internal standard, acenaphthylene. The specificity of the stability-indicating HPLC and iodometric procedures are presented for benzoyl peroxide.

High-performance liquid chromatography of two peripheral vasodilators, nylidrin hydrochloride and isoxsuprine hydrochloride, in pharmaceutical dosage forms

A reliable and selective high-pressure liquid chromatographic (HPLC) procedure for the quantitative determination of nylidrin hydrochloride or isoxsuprine hydrochloride in pharmaceutical dosage forms is described. The specificity of the stability-indicating HPLC procedure is presented for nylidrin hydrochloride.