Vascular endothelial growth factor and placental growth factor release in cultured trophoblast cells under different oxygen tensions

The oxygen status of the placenta during pregnancy is unclear although it has been hypothesised that in pre-eclampsia large regions of the placenta are hypoxic. Circulating levels of vascular endothelial growth factor (VEGF) are increased in women with pre-eclampsia, while circulating placental growth factor (PlGF) levels are decreased. We hypothesise that secreted levels of VEGF are increased in cultures of trophoblast cells under lowered oxygen conditions while secreted levels of PlGFare alternatively regulated. Primary isolates of first trimester and term cytotrophoblasts cells were cultured in 20 and 5% oxygen for 24h. There was a significant increase in the levels of VEGF secreted fromfirst trimester and term cytotrophoblast cells cultured under lowered oxygen conditions compared to the controls while there was a significant decrease in the secreted levels of PIGF in the same cell populations (as measured by ELISA). In first trimester and term trophoblast cells the presence of VEGF (121, 165 and 189) and PlGF (132 and 152) mRNA were demonstrated in both groups by reverse transcription-polymerase chain reaction (RT-PCR). These altered levels of secreted VEGF andPIGF may be released as compensatory molecules in the pathogenesis of diseases such as pre-eclampsia and intrauterine growth restriction.

Glucofuranosylation with penta-O-propanoyl-beta-D-glucofuranose

Readily available, crystalline penta-O-propanoyl-beta-D-glucofuranose is shown to be a suitable glycosylating agent for the acid-catalysed, direct synthesis of O-, S- and N-glucofuranosyl compounds. Beta-linked products are formed with good selectivity. Reaction with cyanotrimethylsilane gave the 1,2-O-(1-cyanopropylidene)acetal rather than the C-glycosyl cyanide. By selective acid-catalysed hydrolysis, the title compound was converted to the 1-hydroxy analogue from which the trichloroacetimidates were made as further potential glycosylating agents.

Exposure to power frequency electric fields and the risk of childhood cancer in the UK

The United Kingdom Childhood Cancer Study, a population-based case-control study covering the whole of Great Britain, incorporated a pilot study measuring electric fields. Measurements were made in the homes of 473 children who were diagnosed with a malignant neoplasm between 1992 and 1996 and who were aged 0-14 at diagnosis, together with 453 controls matched on age, sex and geographical location. Exposure assessments comprised resultant spot measurements in the child's bedroom and the family living-room. Temporal stability of bedroom fields was investigated through continuous logging of the 48-h vertical component at the child's bedside supported by repeat spot measurements. The principal exposure metric used was the mean of the pillow and bed centre measurements. For the 273 cases and 276 controls with fully validated measures, comparing those with a measured electric field exposure >/=20 V m(-1) to those in a reference category of exposure <10 V m(-1), odds ratios of 1.31 (95% confidence interval 0.68-2.54) for acute lymphoblastic leukaemia, 1.32 (95% confidence interval 0.73-2.39) for total leukaemia, 2.12 (95% confidence interval 0.78-5.78) for central nervous system cancers and 1.26 (95% confidence interval 0.77-2.07) for all malignancies were obtained. When considering the 426 cases and 419 controls with no invalid measures, the corresponding odds ratios were 0.86 (95% confidence interval 0.49-1.51) for acute lymphoblastic leukaemia, 0.93 (95% confidence interval 0.56-1.54) for total leukaemia, 1.43 (95% confidence interval 0.68-3.02) for central nervous system cancers and 0.90 (95% confidence interval 0.59-1.35) for all malignancies. With exposure modelled as a continuous variable, odds ratios for an increase in the principal metric of 10 V m(-1) were close to unity for all disease categories, never differing significantly from one.

Novel ATP6V1B1 and ATP6V0A4 mutations in autosomal recessive distal renal tubular acidosis with new evidence for hearing loss

Autosomal recessive distal renal tubular acidosis (rdRTA) is characterised by severe hyperchloraemic metabolic acidosis in childhood, hypokalaemia, decreased urinary calcium solubility, and impaired bone physiology and growth. Two types of rdRTA have been differentiated by the presence or absence of sensorineural hearing loss, but appear otherwise clinically similar. Recently, we identified mutations in genes encoding two different subunits of the renal alpha-intercalated cell's apical H(+)-ATPase that cause rdRTA. Defects in the B1 subunit gene ATP6V1B1, and the a4 subunit gene ATP6V0A4, cause rdRTA with deafness and with preserved hearing, respectively. We have investigated 26 new rdRTA kindreds, of which 23 are consanguineous. Linkage analysis of seven novel SNPs and five polymorphic markers in, and tightly linked to, ATP6V1B1 and ATP6V0A4 suggested that four families do not link to either locus, providing strong evidence for additional genetic heterogeneity. In ATP6V1B1, one novel and five previously reported mutations were found in 10 kindreds. In 12 ATP6V0A4 kindreds, seven of 10 mutations were novel. A further nine novel ATP6V0A4 mutations were found in "sporadic" cases. The previously reported association between ATP6V1B1 defects and severe hearing loss in childhood was maintained. However, several patients with ATP6V0A4 mutations have developed hearing loss, usually in young adulthood. We show here that ATP6V0A4 is expressed within the human inner ear. These findings provide further evidence for genetic heterogeneity in rdRTA, extend the spectrum of disease causing mutations in ATP6V1B1 and ATP6V0A4, and show ATP6V0A4 expression within the cochlea for the first time.

Toward a general strategy for the synthesis of 3,4-dihydroxyprolines from pentose sugars

A general strategy is proposed, wherein a pentose sugar gamma-lactone can be converted, via a series of nine reactions, to a 3,4-dihydroxyproline, suitably protected for use in peptide synthesis. Thus, D-ribonolactone (6) has been converted to N-fluorenylmethoxycarbonyl-3,4-di-O-tert-butyldimethylsilyloxy-D-2,3-cis-3,4-cis-proline (7) in 18.9% overall yield. Likewise, L-arabinonolactone (11) has been converted to N-fluorenylmethoxycarbonyl-3,4-di-O-tert-butyldimethylsilyloxy-L-2,3-cis-3,4-trans-proline (36) in 13.7% overall yield and L-lyxonolactone (12) to N-fluorenylmethoxycarbonyl-3,4-di-O-tert-butyldimethylsilyloxy-L-2,3-trans-3,4-cis-proline (37) in 11.2% overall yield. These building blocks have also been fully deprotected to give the free amino acids. We believe that this series of reactions ought to be applicable to the synthesis of any of the eight stereoisomers of 3,4-dihydroxyproline, by judicious selection of the pentose starting material.

Factors controlling alkylbenzene sorption to municipal solid waste

The sorption of toluene and o-xylene to individual municipal solid waste (MSW) constituents [office paper, newsprint, model food and yard waste, high density polyethylene, and poly(vinyl chloride) (PVC)] was evaluated. Effects of sorbent decomposition and solvent composition on alkylbenzene sorption were studied by evaluating biodegradable sorbents in both fresh and anaerobically decomposed form and by complementing single-solute isotherm tests with experiments conducted in acidogenic and methanogenic leachate. Alkylbenzene sorption to plastics was greaterthan to biopolymer composites, and differences in sorbate/sorbent solubility parameter compatibility explained this observation. Alkylbenzene sorption to biopolymer composites yielded linear isotherms, and sorption capacities [log(Koc/Kow)] decreased linearly with increasing sorbent polarity as expressed by the O-alkyl/alkyl ratio. Leachate composition had little effect on alkylbenzene sorption with one exception; volatile fatty acids in acidogenic leachate appeared to convert PVC from a glassy to a rubbery polymer. The results of this study showed that sorbent organic matter affinity for hydrophobic organic contaminants (HOCs) increases with increasing extent of MSW decomposition because of the recalcitrance of plastics and the preferential degradation of polar biopolymers. Furthermore, the plasticizing effect of volatile fatty acids in acidogenic leachate may enhance the bioavailability of HOCs sorbed to glassy organic matter in MSW or in soils contaminated with acidogenic leachate.

Molecular characterization and ophthalmic investigation of a large family with type 2A Von Hippel-Lindau Disease

BACKGROUND

Von Hippel-Lindau (VHL) disease is a dominantly inherited cancer syndrome. Since the identification of the VHL gene, at least 3 clinical-genetic subtypes of the disease have been recognized.

OBJECTIVES

To identify the specific abnormality in the VHL gene and to correlate it with the prevalence and severity of ocular involvement in a large family with VHL disease.

METHODS

A longitudinal clinical study and DNA analysis of 24 family members.

RESULTS

All 14 affected family members exhibited a thymine-to-cysteine change at nucleotide 505 (T505C) in exon 1 of the VHL gene, consistent with the clinical diagnosis of VHL disease subtype 2A. Two asymptomatic gene carriers were also identified. Seventy-five percent (12/16) of the gene carriers had 1 or more ocular angiomas. The mean number of ocular angiomas per gene carrier was 3.3. Six eyes had optic disc angioma. Five gene carriers (31%) had lost vision because of angiomatosis. Cerebellar hemangioblastomas were present in 4 patients (25%) and pheochromocytomas in 11 (69%). No patient was found to have a renal cell carcinoma.

CONCLUSIONS

The family shows a low susceptibility to renal carcinoma consistent with the clinical diagnosis of VHL disease type 2A. The prevalence and severity of ocular angiomatosis in this subtype do not significantly differ from those of the other more common subtypes of VHL. Recognition of the VHL disease 2A phenotype suggests the presence of a specific mutation (T505C) in the VHL gene. Confirmation of this genotype increases the clinician's ability to provide favorable prognostic information to affected family members.

A novel dipolar dephasing method for the slow magic angle turning experiment

Complete suppression of the resonances from protonated carbons in a slow magic angle spinning experiment can be achieved using five dipolar dephasing (Five-DD) periods distributed in one rotor period. This produces a spectrum containing only the spinning sidebands (SSB) from the nonprotonated carbons. It is shown that the SSB patterns corresponding to the nonprotonated carbons are not distorted over a wide range of dipolar dephasing times. Hence, this method can be used to obtain reliable principal values of the chemical shift tensors for each nonprotonated carbon. The Five-DD method can be readily incorporated into isotropic-anisotropic 2D experiments such as FIREMAT and 2D-PASS to facilitate the measurement of the (13)C chemical shift tensors in complex systems.

Hemolytic-uremic syndrome and complement factor H deficiency: clinical aspects

A subgroup of patients with hemolytic-uremic syndrome (HUS) has emerged with complement factor H deficiency. These have come to light because of persistent hypocomplementemia, although the molecular finding by Warwicker et al in one pedigree suggests that not all cases exhibit systemic hypocomplementemia. These patients have an atypical presentation in that they do not consistently have a prodrome of enterocolitis although precipitating factors may include infections of various kinds. Patients usually have severe hypertension early in the course of their illness, tend to relapse, and have a poor prognosis. The age of onset varies from neonates to adults. Plasma exchange and replacement with a plasma product containing factor H seem a reasonable option in the absence of better evidence. Kidney transplantation can meet with recurrence of HUS, but the risk of grafting has yet to be established, and a strategy to overcome graft recurrence is needed. Because of the great rarity of this disorder, a strong case can be made for international registries of atypical HUS cases so that clinical and laboratory investigation is promoted.

Congenital nephrotic syndrome

A female infant born at 34 weeks' gestation after several days of ruptured membranes had a Potter-like face and compression-induced limb posture consistent with oligohydramnios. Oedema developed on day 2; initial investigations showed massive proteinuria, hypoalbuminaemia, hyponatraemia, acidosis and marked renal insufficiency. The infant was intubated and despite albumin infusion and intravenous antibiotics she became oligoanuric by day 8 and required haemofiltration. Renal biopsy at this stage showed cystic dilatation of tubules in the cortex and glomerular lesions consisting of shrunken tufts with sclerotic centres and a corona of epithelial cells at the periphery. Due to a very poor prognosis treatment was withdrawn. Postmortem examination of the kidneys confirmed the histological diagnosis of diffuse mesangial sclerosis. Genetic studies found no mutations in WT1 and NPHS1 genes although the entire genes could not be screened for mutations due to lack of DNA.

Visual and haptic perception of the horizontal-vertical illusion

The horizontal-vertical illusion consists of two lines of the same length (one horizontal and the other vertical) at a 90 degree angle from one another forming either an inverted-T or an L-shape. The illusion occurs when the length of a vertical line is perceived as longer than the horizontal line even though they are the same physical length. The illusion has been shown both visually and haptically. The present purpose was to assess differences between the visual or haptic perception of the illusions and also whether differences occur between the inverted-T and the L-shape illusions. The current study showed a greater effect in the haptic perception of the horizontal-vertical illusion than in visual perception. There is also greater illusory susceptibility of the inverted-T than the L-shape.

Microbiological testing of raw, boxed beef in the context of hazard analysis critical control point at a high-line-speed abattoir

The efficacy of cold storage of raw, bagged, boxed beef was assessed microbiologically at a high-line-speed abattoir (270 carcasses per h). At the time of this study, plant management was in the process of creating a hazard analysis critical control point plan for all processes. Aerobic bacteria, coliforms, and type 1 Escherichia coli were enumerated (5 by 5-cm excision samples, hydrophobic grid membrane filter technology) before and after cold storage of this final product produced at six fabrication tables. In addition, the temperature-function integration technique (TFIT) was used to calculate the potential number of generations of E. coli during the first 24 or 48 h of storage of the boxed beef. Based on the temperature histories (total of 60 boxes, resulting from 12 product cuts, five boxes from each of two fabrication tables on each of 6 sampling days, and six types of fabrication tables), TFIT did not predict any growth of E. coli (with or without lag) for the test period. This was verified by E. coli mean log10 values of 0.65 to 0.42 cm2 (P > 0.05) determined by culture before and after the cooling process, respectively. Counts of aerobic bacteria and coliforms were significantly reduced (P < 0.001 and P < 0.05, respectively) during the initial period of the cooling process. There were significant microbiological differences (P < 0.05) between table-cut units.

Iron overload and iron-chelating therapy in hemoglobin E-beta thalassemia

Whereas hemoglobin (Hb) E-beta thalassemia is recognized as probably the most common serious hemoglobinopathy worldwide, its natural history remains poorly defined. The interaction of hemoglobin E and beta-thalassemia result in a wide spectrum of clinical disorders, some indistinguishable from thalassemia major and some milder and not transfusion-dependent. Partially as a result of this wide range of phenotypes, clear guidelines for approaches to transfusion and to iron-chelating therapy for patients with Hb E-beta thalassemia have not been developed. By contrast, data that have accumulated during the past 10 years in patients with beta-thalassemia permit a quantitative approach to the management of iron overload and provide guidelines for the control of body iron burden in individual patients treated with iron-chelating therapy. These guidelines may be applicable to patients with Hb E-beta thalassemia. Preliminary evidence from our studies of iron loading in affected patients with Hb E-beta thalassemia in Sri Lanka suggest that this disorder may be associated with variable, but accelerated, gastrointestinal iron absorption, and that the iron loading associated with chronic transfusions in patients with Hb E-beta thalassemia is similar to that observed in patients with beta-thalassemia. These data, in the only cohort of patients with Hb E-beta thalassemia to have undergone quantitative assessment of body iron burden, suggest that the principles that guide assessment of iron loading and initiation of chelating therapy in patients with beta-thalassemia may be generally applicable to those with Hb E-beta thalassemia. Further quantitative studies in both nontransfused and transfused patients will be necessary to permit firm conclusions.

Role of nitric oxide in a toxin-induced model of haemolytic uraemic syndrome

The role of nitric oxide in the pathogenesis of glomerular thrombotic microangiopathy was explored using an established rat model in which ricin with or without lipopolysaccharide induced glomerular thrombosis. Ricin alone caused a small rise in the plasma concentration of nitric oxide (control 9.2+/-0.7 microM, ricin 23.3+/-6.3 microM at 7 h). This increase occurred after the development of glomerular thrombosis. Nitric oxide synthase (NOS) activity in the kidney showed no significant change from control values (control 5.66+/-2.7 pmol/min per ml homogenate, ricin 7.52+/-1.8 pmol/min per ml homogenate, total activity). When ricin and lipopolysaccharide were administered together, calcium-independent NOS activity increased whereas calcium-dependent activity decreased (1.22+/-2.6 pmol/min per ml homogenate). The increase in calcium-independent NOS activity correlated with a high plasma concentration of interleukin-1beta in the ricin plus lipopolysaccharide group (4,036.83+/-1,001.5 pg/ml). These data indicate that thrombus formation in a rat model of haemolytic uraemic syndrome is independent of the effects of nitric oxide.