Multiplicity of Plasmodium falciparum infection in pregnancy

Little is known about the distribution and disease association of multiple Plasmodium falciparum infections in pregnant women. Genotyping of the merozoite surface protein-1 region was performed in 332 P. falciparum infected pregnant women in Ghana, and clinical and epidemiologic data were obtained. Overall, 68% of the women were infected with more than one strain (mean number of strains per carrier = 2.9). The multiplicity of infection decreased significantly with an increasing number of pregnancies, and infection with multiple P. falciparum strains was significantly associated with anemia. In logistic regression, women infected with four or more strains were 2.3 times more likely to be anemic than women harboring fewer strains. This association, however, was only observed in women with up to three pregnancies. The results suggest that with increasing gravidity and subsequent infections with multiple strains effective immune mechanisms against more and more strains develop. In pregnant women, the multiplicity of infection may be an important factor for the acquisition and maintenance of immunity against malaria.

Effects of the serine/threonine kinase SGK1 on the epithelial Na(+) channel (ENaC) and CFTR: implications for cystic fibrosis

Cystic fibrosis (CF) is characterized by impaired Cl(-) secretion and increased Na(+) reabsorption in several tissues including respiratory epithelium. Many CFTR mutations have been identified over the past years. However, only a poor correlation between the genotype and lung phenotype was found suggesting additional factors influencing the phenotype and course of the disease. The serine/threonine kinase SGK1 has recently been shown to stimulate the activity of the epithelial Na(+) channel ENaC. A variety of stimuli such as aldosterone, cell shrinkage, insulin or TGF-beta1 stimulate transcription and activate the SGK1 kinase. Here we further examined the effects of SGK1 on ENaC and CFTR which have mutual interactions and we analyzed sgk1 mRNA abundance in lung tissue from CF patients. Coexpression of CFTR and h-SGK1 in Xenopus oocytes increased ENaC currents as previously described. In addition CFTR mediated currents were also stimulated. h-SGK1 accelerated the expression of the amiloride sensitive Na(+)- current in Xenopus oocytes paralleled by increased ENaC-protein abundance in the oocyte membrane, an effect which was reversed by a h-SGK1(K127R) mutation lacking the ATP-binding site. The cation selectivity or Na(+) affinity were not affected. However, coexpression of h-SGK1 with ENaC altered the sensitivity of the Na(+)-channel to the inhibitors amiloride and triamterene. The inhibitory effect of CFTR expression on ENaC current was not affected by coexpression of h-SGK1 in Xenopus oocytes. Lung tissue from CF patients strongly expressed the serine/threonine kinase h-sgk1 which was not the case for non-CF lung tissue. Loss of CFTR function itself in a CF lung epithelial cell line did not increase SGK1 expression. In summary, enhanced expression of h-SGK1 in epithelial cells of CF-lung tissue may be a novel pathophysiological factor contributing to increased Na(+) channel activity and thus to increased Na(+) transport in CF.

Human cytomegalovirus productively infects porcine endothelial cells in vitro

BACKGROUND

The possibility that human cytomegalovirus (HCMV) may infect porcine endothelial cells (ECs) was investigated. This may be relevant during xenotransplantation of porcine cells or organs into human recipients.

METHODS

HCMV was inoculated into low-passage porcine ECs. Replication of virus was detected by development of characteristic cytopathogenic effect. Appearance of immediate early, early, and late antigens was studied by immunocytochemical staining. Infectious virus was detected in human fibroblast cells. Presence of HCMV RNA was studied by Northern Blot and reverse transcriptase polymerase chain reaction.

RESULTS

All parameters indicated that a fresh clinical HCMV isolate productively infects porcine ECs. The same cells do not fully support replication of the laboratory strain Ad 169.

CONCLUSION

Our results may indicate the possibility of cross-species infectivity of HCMV to porcine cells.

[Reproducibility of measurement of ocular pulse amplitude and intraocular pressure using Smartlens]

BACKGROUND

SmartLens (ODC Ophthalmic Development Company AG, Zürich) is a contact lens tonometer, which allows continuous registration of intraocular pressure (IOP) and ocular pulse amplitude (OPA) and simultaneous ophthalmoscopy. The purpose of this study was to evaluate the intra- and interobserver variability and reliability of intraocular pressure and ocular pulse amplitude measurements using SmartLens.

METHODS

To evaluate the intraobserver variability, intraocular pressure (IOP) and ocular pulse amplitude (OPA) were both measured 5 times in 10 healthy eyes by one observer. To evaluate the interobserver variability, intraocular pressure and ocular pulse amplitude were measured by 3 different observers in 10 healthy eyes. Data description is based on coefficients of variation (SD/mean in %), statistical inference on ANOVA-based reliability estimation.

RESULTS

The coefficient of the intraobserver variation was 9.57% for the IOP and 14.5% for the OPA (SD IOP: +/- 1.64 mmHg, SD OPA: +/- 0.39 mmHg). The coefficient of the interobserver variation with 5 replicate measurements was 10.16% for the IOP and 14% for the OPA (SD IOP: +/- 1.83 mmHg, SD OPA: +/- 0.4 mmHg). The interobserver reliability was 87% for the IOP and 86% for the OPA. One of the three observers obtained significantly higher IOP and OPA values.

CONCLUSIONS

SmartLens is a reasonably precise and reliable device for IOP as well as OPA measurements but the results were not found to be observer independent.

The genomic structure and promoter region of the human parkin gene

Parkin has been identified as a causative gene of the autosomal recessive juvenile parkinsonism (AR-JP). In this study, we determined the genomic structure of the Parkin gene and identified a core promoter region based on the DNA sequence of 1.4 Mb. The 5'-flanking region contained no apparent TATA or CAAT box elements but several putative cis-elements for various transcription factors. The GC- and CpG-rich regions were observed not only in the 5'-flanking sequence but also in the 5'-part of the first intron of Parkin. We identified an exact starting point of Parkin transcription. A core promoter region was determined by transfecting a series of deletion constructs with a dual luciferase reporter system into human neuroblastoma cells. Furthermore, we located a neighboring novel gene in a head-to-head direction with Parkin with only a 198-bp interval.

The genomic context of natural killer receptor extended gene families

The two sets of inhibitory and activating natural killer (NK) receptor genes belong either to the Ig or to the C-type lectin superfamilies. Both are extensive and diverse, comprising genes of varying degrees of relatedness, indicative of a process of iterative duplication. We have constructed gene maps to help understand how and when NK receptor genes developed and the nature of their polymorphism. A cluster of over 15 C-type lectin genes, the natural killer complex is located on human chromosome 12p13.1, syntenic with a region in mouse that borders multiple Ly49 loci. The equivalent locus in man is occupied by a single pseudogene, LY49L. The immunoglobulin superfamily of loci, the leukocyte receptor complex (LRC), on chromosome 19q13.4, contains many polymorphic killer cell immunoglobulin-like receptor (KIR) genes as well as multiple related sequences. These include immunoglobulin-like transcript (ILT) (or leukocyte immunoglobulin-like receptor genes), leukocyte-associated inhibitory receptor genes (LAIR), NKp46, Fc alphaR and the platelet glycoprotein receptor VI locus, which encodes a collagen-binding molecule. KIRs are expressed mostly on NK cells and some T cells. The other LRC loci are more widely expressed. Further centromeric of the LRC are sets of additional loci with weak sequence similarity to the KIRs, including the extensive CD66(CEA) and Siglec families. The LRC-syntenic region in mice contains no orthologues of KIRs. Some of the KIR genes are highly polymorphic in terms of sequence as well as for presence/absence of genes on different haplotypes. Some anchor loci, such as KIR2DL4, are present on most haplotypes. A few ILT loci, such as ILT5 and ILT8, are polymorphic, but only ILT6 exhibits presence/absence variation. This knowledge of the genomic organisation of the extensive NK superfamilies underpins efforts to understand the functions of the encoded NK receptor molecules. It leads to the conclusion that the functional homology of human KIR and mouse Ly49 genes arose by convergent evolution. NK receptor immunogenetics has interesting parallels with the major histocompatibility complex (MHC) in which some of the polymorphic genes are ligands for NK molecules. There are hints of an ancient genetic relationship between NK receptor genes and MHC-paralogous regions on chromosomes 1, 9 and 19. The picture that emerges from both complexes is of eternal evolutionary restlessness, presumably in response to resistance to disease.

Characterization of clustered MHC-linked olfactory receptor genes in human and mouse

Olfactory receptor (OR) loci frequently cluster and are present on most human chromosomes. They are members of the seven transmembrane receptor (7-TM) superfamily and, as such, are part of one of the largest mammalian multigene families, with an estimated copy number of up to 1000 ORs per haploid genome. As their name implies, ORs are known to be involved in the perception of odors and possibly also in other, nonolfaction-related, functions. Here, we report the characterization of ORs that are part of the MHC-linked OR clusters in human and mouse (partial sequence only). These clusters are of particular interest because of their possible involvement in olfaction-driven mate selection. In total, we describe 50 novel OR loci (36 human, 14 murine), making the human MHC-linked cluster the largest sequenced OR cluster in any organism so far. Comparative and phylogenetic analyses confirm the cluster to be MHC-linked but divergent in both species and allow the identification of at least one ortholog that will be useful for future regulatory and functional studies. Quantitative feature analysis shows clear evidence of duplications of blocks of OR genes and reveals the entire cluster to have a genomic environment that is very different from its neighboring regions. Based on in silico transcript analysis, we also present evidence of extensive long-distance splicing in the 5'-untranslated regions and, for the first time, of alternative splicing within the single coding exon of ORs. Taken together with our previous finding that ORs are also polymorphic, the presented data indicate that the expression, function, and evolution of these interesting genes might be more complex than previously thought.

The shrinkage-activated Na(+) conductance of rat hepatocytes and its possible correlation to rENaC

At moderate cell shrinkage, activation of Na(+) channels is the most prominent mechanism of regulatory cell volume increase in rat hepatocytes. The amiloride sensitivity of these channels suggests a relation to the family of epithelial Na(+) channels (ENaCs). The present study was performed to determine the pharmacological profile of shrinkage-activated Na(+) channels and to test for ENaC expression in primary cultures of rat hepatocytes; in addition, the influence of the cell volume regulated serine/threonine kinase hSGK on activity and pharmacological profile of rENaC was examined in Xenopus oocytes. Conventional electrophysiology in hepatocytes reveals that the shrinkage-activated Na(+) channel is inhibited by amiloride and EIPA with IC(50) values of 6.0 and 0.12 micromol/l, respectively. Western blots and RT-PCR demonstrate that rat hepatocytes do express all three subunits (alpha, beta, gamma) of ENaC. Coexpression of hSGK with rENaC in Xenopus oocytes reveals that the kinase stimulates ENaC by a factor of 4. Moreover, hSGK decreases the affinity to amiloride (increase of IC(50) from 0.12 to 0.26 micromol/l) and increases the affinity to EIPA (decrease of IC(50) from 250 to 50 micromol/l). In conclusion, rat hepatocytes express ENaC, which is activated by the cell volume-sensitive kinase hSGK. ENaC may contribute to the Na(+) channels activated by osmotic cell shrinkage in hepatocytes, whereby the relatively low amiloride and high EIPA sensitivity of the channel could at least be partially due to modification by SGK, which decreases the amiloride and increases the EIPA sensitivity of ENaC.

Initial sequencing and analysis of the human genome

The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

The cluster of BTN genes in the extended major histocompatibility complex

We sequenced the 170-kb cluster of BTN genes in the extended major histocompatibility complex region, 4 Mb telomeric of human leukocyte antigen class I genes, at 6p22.1. The cluster consists of seven genes belonging to the expanding B7/butyrophilin-like group, a subset of the immunoglobulin gene superfamily. The main complex is composed of six genes, from two subfamilies, BTN2 and BTN3, arranged in pairs. This alternating pattern must have evolved by duplications of an original block of two genes, one from each subfamily. The sequences from the two subfamilies share approximately 50% amino acid identity. By analysis of repeat elements within each block, these duplications may be dated to approximately 100 million years ago, at about the time of the branching of the Rodentia and Primate lineages. The single BTN1A1 (butyrophilin) gene was positioned approximately 25 kb centromeric to the cluster. Each gene covers approximately 12 kb and consists of seven (BTN2 subfamily) or nine (BTN3 subfamily) coding exons. The predicted leader sequence, immunoglobulin-like IgV (variable)/IgC (constant) ectodomains, and the predicted transmembrane domain are encoded on separate exons and are separated from a B30.2 domain by a variable number of very short exons, 21 and 27 nucleotides in length. BTN transcripts were detected in all tissues examined. Alternative splicing, involving particularly the carboxyl-terminal B30.2 domain, was a notable feature. Most transcripts of BTN2 subfamily genes contained this domain, whereas BTN3 genes did not. Using immunofluorescence, we showed surface expression of BTN-green fluorescent protein fusions in mammalian cell transfectants.

Motor thresholds in humans: a transcranial magnetic stimulation study comparing different pulse waveforms, current directions and stimulator types

OBJECTIVES

To evaluate the stimulation effectiveness of different magnetic stimulator devices with respect to pulse waveform and current direction in the motor cortex.

METHODS

In 8 normal subjects we determined motor thresholds of transcranial magnetic stimulation in a small hand muscle. We used focal figure-of-eight coils of 3 common stimulators (Dantec Magpro, Magstim 200 and Magstim Rapid) and systematically varied current direction (postero-anterior versus antero-posterior, perpendicular to the central sulcus) as well as pulse waveform (monophasic versus biphasic). The coil position was kept constant with a stereotactic positioning device.

RESULTS

Motor thresholds varied consistently with changing stimulus parameters, despite substantial interindividual variability. By normalizing the values with respect to the square root of the energy of the capacitors in the different stimulators, we found a homogeneous pattern of threshold variations. The normalized Magstim threshold values were consistently higher than the normalized Dantec thresholds by a factor of 1.3. For both stimulator types the monophasic pulse was more effective if the current passed the motor cortex in a postero-anterior direction rather than antero-posterior. In contrast, the biphasic pulse was weaker with the first upstroke in the postero-anterior direction. We calculated mean factors for transforming the intensity values of a particular configuration into that of another configuration by normalizing the different threshold values of each individual subject to his lowest threshold value.

CONCLUSIONS

Our transformation factors allow us to compare stimulation intensities from studies using different devices and pulse forms. The effectiveness of stimulation as a function of waveform and current direction follows the same pattern as in a peripheral nerve preparation (J Physiol (Lond) 513 (1998) 571).

Synthesis, structures, and reactivity of weakly coordinating anions with delocalized borate structure: the assessment of anion effects in metallocene polymerization catalysts

The formation of adducts of tris(pentafluorophenyl)borane with strongly coordinating anions such as CN(-) and [M(CN)(4)](2)(-) (M = Ni, Pd) is a synthetically facile route to the bulky, very weakly coordinating anions [CN[B(C(6)F(5))(3)](2)](-) and [M[CNB(C(6)F(5))(3)](4)](2-) which are isolated as stable NHMe(2)Ph(+) and CPh(3)(+) salts. The crystal structures of [CPh(3)][CN[B(C(6)F(5))(3)](2)] (1), [CPh(3)][ClB(C(6)F(5))(3)] (2), [NHMe(2)Ph](2)[Ni[CNB(C(6)F(5))(3)](4)].2Me(2)CO (4b.2Me(2)CO), [CPh(3)](2)[Ni[CNB(C(6)F(5))(3)](4)].2CH(2)Cl(2) (4c.2CH(2)Cl(2)), and [CPh(3)](2)[Pd[CNB(C(6)F(5))(3)](4)].2CH(2)Cl(2) (5c.2CH(2)Cl(2)) are reported. The CN stretching frequencies in 4 and 5 are shifted by approximately 110 cm(-1) to higher wavenumbers compared to the parent tetracyano complexes in aqueous solution, although the M-C and C-N distances show no significant change on B(C(6)F(5))(3) coordination. Zirconocene dimethyl complexes L(2)ZrMe(2) [L(2) = Cp(2), SBI = rac-Me(2)Si(Ind)(2)] react with 1, 4c or 5c in benzene solution at 20 degrees C to give the salts of binuclear methyl-bridged cations, [(L(2)ZrMe)(2)(mu-Me)][CN[B(C(6)F(5))(3)](2)] and [(L(2)ZrMe)(2)(mu-Me)](2)[M[CNB(C(6)F(5))(3)](4)]. The reactivity of these species in solution was studied in comparison with the known [[(SBI)ZrMe](2)(mu-Me)][B(C(6)F(5))(4)]. While the latter reacts with excess [CPh(3)][B(C(6)F(5))(4)] in benzene to give the mononuclear ion pair [(SBI)ZrMe(+).B(C(6)F(5))(4)(-)] in a pseudo-first-order reaction, k = 3 x 10(-4) s(-1), [(L(2)ZrMe)(2)(mu-Me)][CN[B(C(6)F(5))(3)](2)] reacts to give a mixture of L(2)ZrMe(mu-Me)B(C(6)F(5))(3) and L(2)ZrMe(mu-NC)B(C(6)F(5))(3). Recrystallization of [Cp' '(2)Zr(mu-Me)(2)AlMe(2)][CN[B(C(6)F(5))(3)](2)] affords Cp' '(2)ZrMe(mu-NC)B(C(6)F(5))(3) 6, the X-ray structure of which is reported. The stability of [(L(2)ZrMe)(2)(mu-Me)](+)X(-) decreases in the order X = [B(C(6)F(5))(4)] > [M[CNB(C(6)F(5))(3)](4)] > [CN[B(C(6)F(5))(3)](2)] and increases strongly with the steric bulk of L(2) = Cp(2) << SBI. Activation of (SBI)ZrMe(2) by 1 in the presence of AlBu(i)(3) gives extremely active ethene polymerization catalysts. Polymerization studies at 1-7 bar monomer pressure suggest that these, and by implication most other highly active ethene polymerization catalysts, are strongly mass-transport limited. By contrast, monitoring propene polymerization activities with the systems (SBI)ZrMe(2)/1/AlBu(i)(3) and CGCTiMe(2)/1/AlBu(i)(3) at 20 degrees C as a function of catalyst concentration demonstrates that in these cases mass-transport limitation is absent up to [metal] approximately 2 x 10(-5) mol L(-1). Propene polymerization activities decrease in the order [CN[B(C(6)F(5))(3)](2)](-) > [B(C(6)F(5))(4)](-) > [M[CNB(C(6)F(5))(3)](4)](2-) >> [MeB(C(6)F(5))(3)](-), with differences in activation barriers relative to [CN[B(C(6)F(5))(3)](2)](-) of DeltaDeltaG = 1.1 (B(C(6)F(5))(4)(-)), 4.1 (Ni[CNB(C(6)F(5))(3)](4)(2-)) and 10.7-12.8 kJ mol(-)(1) (MeB(C(6)F(5))(3)(-)). The data suggest that even in the case of very bulky anions with delocalized negative charge the displacement of the anion by the monomer must be involved in the rate-limiting step.

Subduction and collision processes in the Central Andes constrained by converted seismic phases

The Central Andes are the Earth's highest mountain belt formed by ocean-continent collision. Most of this uplift is thought to have occurred in the past 20 Myr, owing mainly to thickening of the continental crust, dominated by tectonic shortening. Here we use P-to-S (compressional-to-shear) converted teleseismic waves observed on several temporary networks in the Central Andes to image the deep structure associated with these tectonic processes. We find that the Moho (the Mohorovicić discontinuity--generally thought to separate crust from mantle) ranges from a depth of 75 km under the Altiplano plateau to 50 km beneath the 4-km-high Puna plateau. This relatively thin crust below such a high-elevation region indicates that thinning of the lithospheric mantle may have contributed to the uplift of the Puna plateau. We have also imaged the subducted crust of the Nazca oceanic plate down to 120 km depth, where it becomes invisible to converted teleseismic waves, probably owing to completion of the gabbro-eclogite transformation; this is direct evidence for the presence of kinetically delayed metamorphic reactions in subducting plates. Most of the intermediate-depth seismicity in the subducting plate stops at 120 km depth as well, suggesting a relation with this transformation. We see an intracrustal low-velocity zone, 10-20 km thick, below the entire Altiplano and Puna plateaux, which we interpret as a zone of continuing metamorphism and partial melting that decouples upper-crustal imbrication from lower-crustal thickening.

MHC-linked olfactory receptor loci exhibit polymorphism and contribute to extended HLA/OR-haplotypes

Clusters of olfactory receptor (OR) genes are found on most human chromosomes. They are one of the largest mammalian multigene families. Here, we report a systematic study of polymorphism of OR genes belonging to the largest fully sequenced OR cluster. The cluster contains 36 OR genes, of which two belong to the vomeronasal 1 (V1-OR) family. The cluster is divided into a major and a minor region at the telomeric end of the HLA complex on chromosome 6. These OR genes could be involved in MHC-related mate preferences. The polymorphism screen was carried out with 13 genes from the HLA-linked OR cluster and three genes from chromosomes 7, 17, and 19 as controls. Ten human cell lines, representing 18 different chromosome 6s, were analyzed. They were from various ethnic origins and exhibited different HLA haplotypes. All OR genes tested, including those not linked to the HLA complex, were polymorphic. These polymorphisms were dispersed along the coding region and resulted in up to seven alleles for a given OR gene. Three polymorphisms resulted either in stop codons (genes hs6M1-4P, hs6M1-17) or in a 16-bp deletion (gene hs6M1-19P), possibly leading to lack of ligand recognition by the respective receptors in the cell line donors. In total, 13 HLA-linked OR haplotypes could be defined. Therefore, allelic variation appears to be a general feature of human OR genes.

Polymorphisms in olfactory receptor genes: a cautionary note

The hundreds of human olfactory receptor (OR) genes are organized into clusters occurring on nearly every chromosome. Although their sequences are not always closely related, they share stretches of considerable similarity, both at the amino acid and nucleotide levels. We demonstrate here that an HLA complex-linked OR sequence, FAT11, for which recently a number of alleles have been claimed within the Hutterites, contains sequences derived from two closely related, linked OR genes, hs6M1-12 and hs6M1-16. Instead of indicating a difference between alleles of a given locus, two of the polymorphisms described for FAT11 (at amino acids 48 and 220 of the deduced protein sequence, respectively) may in fact reflect distinct sequences of hs6M1-12 and a further, closely related HLA-linked OR locus, hs6M1-13P. As a consequence, recombination rates in Hutterites in the region telomeric of HLA-G may have to be reconsidered.

Arrangement of the ILT gene cluster: a common null allele of the ILT6 gene results from a 6.7-kbp deletion

The leukocyte receptor cluster (LRC) is a highly polymorphic region of human chromosome 19q13.4 that encompasses at least 24 members of the immunoglobulin superfamily (Ig-SF). The centromeric end of the LRC contains eight Ig-SF loci, namely LAIR1 and seven ILT genes. All ILT genes conform to prototypic ILT gene structures. ILT6 is the only member of the ILT family that lacks a transmembrane and cytoplasmic domain. Close examination of the ILT6 genomic sequence reveals high similarity of this locus with the organization of activating ILT genes. However, the ILT6 transcript runs through the putative splice site of exon 8 that encodes for an extracellular stalk region, leading to a premature in-frame stop codon. Downstream of exon 8 are three pseudo exons that are not included in any of the known ILT6 transcripts, but share high homology to the equivalent region in activating ILT loci, suggesting that these genes have evolved from a common ancestral sequence. Comparison of two haplotypes over this region revealed a remarkable polymorphism with respect to the ILT6 gene which lacks exons 1-7 in one allele, reminiscent of the presence/absence variation displayed by the closely related and genetically linked KIR loci. Detailed sequence analysis of the two LAIR/ILT clusters suggests that the two complexes may have evolved from an inverted duplication.

Small GTPase Rac1: structure, localization, and expression of the human gene

Rac1 is a member of the Rho family of small GTPases involved in signal transduction pathways that control proliferation, adhesion, and migration of cells during embryonic development and invasiveness of tumor cells. Here we present the complete structure of the human RAC1 gene and characterize its expression. The gene comprises 7 exons over a length of 29 kb and is localized to chromosome 7p22. The GC-rich gene promoter shows characteristics of a housekeeping gene and Northern blot studies revealed ubiquitous expression of two rac1 transcripts, 1.2 and 2.5 kb in size. The two transcripts are expressed in tissue-specific ratios, reflecting competition between two alternative polyadenylation sites. The RAC1 but not RAC2 gene contains an additional exon 3b that is included by alternative splicing into the variant Rac1b, a constitutively active mutant which induces the formation of lamellipodia in fibroblasts. These data indicate that the RAC1 gene encodes two signaling GTPases. The gene structure reported here will enable studies on the regulation of RAC1 expression during tumorigenesis and development.

Anaemia in pregnant Ghanaian women: importance of malaria, iron deficiency, and haemoglobinopathies

In sub-Saharan Africa, anaemia in pregnancy results from multiple causes including malaria, iron deficiency and haemoglobinopathies. In a cross-sectional study among 530 pregnant women in Ghana in November-December 1998, red blood cell indices were analysed with respect to malaria, serum concentrations of ferritin and C-reactive protein (CRP), and the haemoglobin and alpha-globin genotypes. Anaemia (haemoglobin [Hb] < 11 g/dL) was found in 54% of the women; 63% harboured malaria parasites at predominantly low numbers. Ferritin levels were considerably influenced by malaria and inflammatory processes (CRP > 0.6 mg/dL). Depending on the definition applied, the prevalence of iron deficiency ranged between 5% and 46%. The HbAS trait was observed in 14%, HbAC and elevated HbF in 7% each, and sickle cell disease in 1%. Heterozygous beta-thalassaemia was present in 1% of the women and alpha(+)-thalassaemia in 33% (29% heterozygous, 4% homozygous). Women with HbAS had higher malaria parasite densities than those with HbAA. In individuals with highly elevated HbF (> 10%), parasitaemia occurred in 27% only. Low gravidity, second trimester of pregnancy, malaria, raised CRP levels, and homozygous alpha(+)-thalassaemia were independent risk factors for anaemia in multivariate analysis. alpha(+)-Thalassaemia, however, was associated with a lesser degree of malarial anaemia when compared to non-thalassaemic women. Iron deficiency appears not to be a major health problem in this population. Haemoglobinopathies are common but, except for homozygous alpha(+)-thalassaemia, do not substantially contribute to anaemia in pregnancy. alpha(+)-Thalassaemia ameliorates malarial anaemia in pregnant women.

Characterization and predictors of prostate specific antigen progression rates after radical retropubic prostatectomy

PURPOSE

Detectable serum prostate specific antigen (PSA) after radical prostatectomy indicates recurrent disease and treatment failure. We characterized PSA recurrence after prostatectomy and identified predictors of rapid PSA progression.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 165 patients with detectable PSA after radical prostatectomy to characterize the rate of PSA increase and correlate this rate with the possible predictors of rapid PSA progression known at prostatectomy.

RESULTS

For a median of 48 months postoperatively we followed 142 patients with PSA recurrence after radical prostatectomy who received no immediate adjuvant therapy. PSA doubling time was less than 6, greater than 6, 12, 18 and 24 months in 46%, 54%, 18%, 11% and 9% of cases, while time to PSA 50 ng./ml. was greater than 5, 10, 15 and 20 years in 69%, 34%, 22% and 9%, respectively. Univariate and multivariate analyses revealed that rapid PSA doubling time was associated with Gleason secondary grade, Gleason score and time to initial detectable PSA (p = 0.019, 0.031 and 0.0001, and p = 0.043, 0.045 and 0.0001, respectively).

CONCLUSIONS

PSA recurrence progresses at a greatly variable rate and many recurrences progress slowly with a long doubling time. Gleason secondary grade and score appear to be predictive of rapid PSA progression. No other pathological features were predictive of rapid PSA progression.

G protein betagamma complexes in circumvallate taste cells involved in bitter transduction

G protein betagamma (Gbetagamma) complexes are considered to play an important role in second messenger signaling of phospholipase C (PLC). Monitoring the inositol 1,4,5-trisphosphate (IP(3)) response in circumvallate tissue homogenates upon stimulation with denatonium benzoate, it was demonstrated that a glutathione S-transferase-GRK3ct fusion protein-a Gbetagamma scavenger-attenuates the bitter tastant-induced second messenger reaction. Towards an identification of the Gbetagamma complex involved in rat bitter taste transduction, it was found that the G protein beta(3) subtype is specifically expressed in taste receptor cells of circumvallate papillae. Gbeta(3)-specific antibodies blocked the denatonium benzoate-induced IP(3) formation in a dose-dependent manner; the inhibitory effect was reversed by preincubation with the antigenic peptide. A less pronounced inhibition was observed using Gbeta(1)-specific antibodies. Analyzing individual taste cells by single cell reverse transcriptase-polymerase chain reaction approaches, overlapping expression patterns for PLCbeta(2), Galpha(gust), Gbeta(3) and Ggamma(3) could be demonstrated. Furthermore, the co-expression of all profiled signal transduction components in individual taste receptor cells could be detected. These data support the concept that the denatonium benzoate-induced IP(3) response is mediated by an activation of PLCbeta(2) via a Gbetagamma complex, possibly composed of Gbeta(3) as the predominant beta subunit and Ggamma(3), and imply that multiple second messenger pathways may exist in individual taste receptor cells.

Cystic fibrosis F508del patients have apically localized CFTR in a reduced number of airway cells

Present state of knowledge, mostly based on heterologous expression studies, indicates that the cystic fibrosis transmembrane conductance regulator (CFTR) protein bearing the F508del mutation is misprocessed and mislocalized in the cytoplasm, unable to reach the cell surface. Recently, however, it was described that protein levels and localization are similar between F508del and wild-type CFTR in airway and intestinal tissues, but not in the sweat glands. In this study, we used immunocytochemistry with three different anti-CFTR antibodies to investigate endogenous CFTR expression and localization in nasal epithelial cells from F508del homozygous patients, F508del carriers, and non-CF individuals. On average, 300 cells were observed per individual. No significant differences were observed for cell type distributions among CF, carrier, and non-CF samples; epithelial cells made up approximately 80% to 95% of all cells present. CFTR was detected mostly in the apical region (AR) of the tall columnar epithelial (TCE) cells, ciliated or nonciliated. By confocal microscopy analysis, we show that the CFTR apical region-staining does not overlap with either anti-calnexin (endoplasmic reticulum), anti-p58 (Golgi), or anti-tubulin (cilia) stainings. The median from results with three antibodies indicate that the apical localization of CFTR happens in 22% of TCE cells from F508del homozygous patients with CF (n = 12), in 42% of cells from F508del carriers (n = 20), and in 56% of cells from healthy individuals (n = 12). Statistical analysis indicates that differences are significant among all groups studied and for the three antibodies (p < 0.05). These results confirm the presence of CFTR in the apical region of airway cells from F508del homozygous patients; however, they also reveal that the number of cells in which this occurs is significantly lower than in F508del carriers and much lower than in healthy individuals. These findings may have an impact on the design of novel pharmacological strategies aimed at circumventing the CF defect caused by the F508del mutation.

Activation of peroxisome proliferator-activated receptor-gamma pathway inhibits osteoclast differentiation

The nuclear receptor and transcription factor, peroxisome proliferator-activated receptor-gamma (PPAR-gamma), regulates the activity of other transcription factors in the adipogenic differentiation and inflammatory response pathways. We examined the possible function of the PPAR-gamma pathway in osteoclast (Ocl) formation from CD34(+) hematopoietic stem cells (CD34(+) HSCs), using a co-culture system comprised of human mesenchymal stem cells (hMSCs) and CD34(+) HSCs, both derived from bone marrow. Ocl formation in this co-culture system is enhanced by the addition of exogenous osteoprotegerin ligand (OPGL), an essential Ocl differentiation factor, and macrophage-colony stimulating factor (M-CSF). The data indicate that soluble OPGL (sOPGL) and M-CSF stimulate Ocl formation in the co-cultures up to 4-fold compared with CD34(+) HSCs alone treated with sOPGL and M-CSF. CD34(+) HSCs, but not hMSCs, express PPAR-gamma, and 15-deoxy-Delta(12, 14)-prostaglandin-J2 (15d-PG-J2), a PPAR-gamma agonist, completely blocked the effects of sOPGL and M-CSF on Ocl formation and activity. The inhibitory effect of 15d-PG-J2 is specific to the Ocl lineage in both human and mouse models of osteoclastogenesis. Accordingly, parallel experiments demonstrate that sOPGL activates the NF-kappaB pathway within mouse Ocl progenitors, and this effect was abolished by 15d-PG-J2. These data establish a link between PPAR-gamma and OPGL signaling within Ocl progenitors, and support a role for PPAR-gamma pathway in the modulation of osteoclastogenesis.