Programmable array microscopy with a ferroelectric liquid-crystal spatial light modulator

We present a programmable array microscope that uses a ferroelectric liquid-crystal spatial light modulator (SLM) for dynamic generation of scanning apertures. A single SLM serves as both the source and the detector aperture array in a double-pass confocal system. Successive aperture frames scan the array across the viewing area for complete imaging of a sample while preserving depth discrimination. Integration of the microscope output across all aperture frames produces a confocal image.

Synthesis of the repeating decapeptide unit of Mefp1 in orthogonally protected form

Mefp1 is a protein produced by the marine mussel, Mytilus edulis, which helps the organism to adhere to surfaces in turbulent waters. To better understand the nature of the adhesion process, we sought to synthesize homogeneous oligopeptides based on the repeating decapeptide unit of the protein. The fully protected decapeptide 10 has been synthesized from appropriately protected amino acid building blocks using a fragment condensation strategy. A key feature of the strategy is the late incorporation of the synthetically valuable dihydroxyproline residue. This synthesis of the orthogonally protected repeating decapeptide unit of Mefp1 represents an important first step toward producing useful quantities of homogeneous oligopeptides related to the protein.

1H dynamic nuclear polarization in supercritical ethylene at 1.4 T

(1)H dynamic nuclear polarization (DNP) has been measured in supercritical ethylene in the pressure range 60-300 bar in an external field of 1.4 T. A single-cell sapphire tube was used as a high-pressure cell, and powdered 1,3-bisdiphenylene-2-phenyl allyl (BDPA) free radicals were added and distributed at the wall of the cell. At all pressures the dominant DNP mechanism was a positive Overhauser enhancement, caused by proton-electron contact interactions at the fluid/solid radical interface. The observed enhancements varied from 12 at 60 bar to 17 at 300 bar. Besides the Overhauser enhancement, small solid state and thermal mixing enhancements also were observed, indicating that part of the ethylene was adsorbed at the radical surface for a prolonged time. The impacts of the experimental conditions on the Overhauser enhancement factors are discussed, and enhancements of at least 40-60 are estimated when the EPR saturation factor and the leakage factor become maximal. These data indicate that DNP-enhanced NMR has the potential of extending the impact of NMR in research areas involving supercritical fluids.

Clinical characterization and linkage analysis of a family with congenital X-linked nystagmus and deuteranomaly

OBJECTIVES

To identify a congenital nystagmus locus on the X chromosome and to characterize the phenotype of a 4-generation family affected with congenital nystagmus and color deficiency.

METHODS

Sixty-five patients underwent an eye examination, including evaluation for the presence of nystagmus and color vision abnormalities. Affected patients and obligate carriers of the congenital nystagmus mutation were genotyped with short tandem repeat polymorphisms located on the X chromosome, and these data were subjected to linkage analysis.

RESULTS

Fourteen patients were affected with a horizontal, conjugate, congenital nystagmus. All examined patients had a visual acuity of 20/60 or better. There were no associated ocular or systemic findings except that 18 of the family members had deficient red-green color vision, which was classified as deuteranomaly (the most common form of anomalous trichromacy). Five patients exhibited nystagmus and deuteranomaly. Significant linkage was demonstrated between the nystagmus phenotype and 11 markers from Xq. The maximum lod score was 4.84 (theta = 0) and was obtained with marker DXS8041. Analysis of recombinants defined the disease interval to lie between markers ATA59C05 and DXS1192 (a 5.4-centimorgan region). The proximity of this locus to the red-green opsin gene cluster (11 centimorgans more telomeric) explains the frequent coexistence of nystagmus and color vision deficiency in this family.

CONCLUSIONS

We have identified the genetic locus of the X-linked congenital nystagmus gene in this family. The critical interval in this report is less than half the size of the previously described nystagmus locus. These findings will aid in identifying the gene responsible for this condition.

Exclusion of AR-CHED from the chromosome 20 region containing the PPMD and AD-CHED loci

Congenital hereditary endothelial dystrophy (CHED) is a disorder of the corneal endothelium and has been recognized to segregate in families with both autosomal dominant (AD) and autosomal recessive (AR) modes of transmission. AD-CHED has been previously linked to the pericentric region of chromosome 20. Posterior polymorphous dystrophy (PPMD), a corneal endothelial disorder showing phenotypic overlap with CHED, has also been previously genetically mapped to this region. The genetic interval containing AD-CHED is within the larger genetic interval containing the PPMD locus. This study sought to determine whether AR-CHED segregating in a consanguineous Saudi Arabian pedigree is linked to the previously mapped and overlapping loci for AD-CHED and PPMD on the pericentric region of chromosome 20. Forty members of a consanguineous Saudi Arabian pedigree segregating AR-CHED were ascertained. Short tandem-repeat polymorphic markers from the 20 cM interval on chromosome 20 containing both the PPMD and AD-CHED loci were used to genotype these individuals. LOD score analysis of the genotype data with the MENDEL software package utilizing a model of autosomal recessive inheritance with complete penetrance showed exclusion of CHED from the entire PPMD/AD-CHED interval by utilizing overlapping intervals of LOD scores of at least -2. The results obtained demonstrate that AR-CHED is not allelic to either AD-CHED or PPMD, although it has been proposed that AD-CHED may be allelic to PPMD. Thus, there are at least two genes responsible for CHED and PPMD.

Synthesis of a protected 3,4-dihydroxyproline from a pentose sugar

[reaction: see text] D-Ribonolactone (6) was transformed into N-((fluorenylmethoxy)carbonyl)-3,4-bis-O-(tert-butyldimethylsilyl)-D-2,3-cis-3,4-cis-3,4-dihydroxyproline (13) in nine chemical steps. This represents a potentially general strategy for the synthesis of 3,4-dihydroxyprolines, utilizing the pentose sugar series as starting materials.

Familial relapsing haemolytic uraemic syndrome and complement factor H deficiency

BACKGROUND

In a recent study of three families we have found that inherited haemolytic uraemic syndrome (HUS) maps to a region of chromosome 1q containing the gene for complement factor H. In one of these families and also in a case of sporadic D-HUS, we have identified mutations in the factor H gene. A further family with inherited HUS has therefore been investigated.

METHODS

DNA extracted from the family members and DNA extracted from archival post-mortem material from a deceased family member, was studied. Review of renal biopsies and study of complement components was also undertaken.

RESULTS

This family demonstrates an inherited deficiency of complement factor H. Non-diarrhoeal HUS has affected at least two family members with half normal levels of factor H.

CONCLUSION

These findings represent further evidence of the association between factor H dysfunction and HUS.

A laboratory model of toxin-induced hemolytic uremic syndrome

BACKGROUND

Verocytotoxin-producing (Shiga-like toxin-producing) Escherichia coli infection is the principal cause of hemolytic uremic syndrome (HUS). The pathogenesis is unclear, and there is a need for animal models. These are impeded by the different distribution of verocytotoxin receptors between species. We have circumvented this restriction using ricin, which gains entry into cells via various galactose receptors. Like verocytotoxin, ricin specifically cleaves a single adenine from ribosomal RNA.

METHODS

Rats were given ricin at a dose of 6.7 micrograms/100 g body wt, with or without lipopolysaccharide at 10 micrograms/100 g body wt. Lipopolysaccharide alone or saline were used as controls. Changes in glomerular filtration rate, hematological parameters, histology, and plasma cytokine concentrations were measured.

RESULTS

Extensive glomerular thrombosis, pyknotic nuclei, and an infiltration of ED1-positive cells into glomeruli were observed eight hours after an injection of ricin. Other vascular beds were unaffected. Histologic changes were preceded by oliguric renal failure, hemolysis, and thrombocytopenia. Ricin produced a rise in plasma concentrations of monocyte chemotactic protein-1, > tumor necrosis factor-alpha, > interleukin-1 beta, > interleukin-6. Interferon-gamma showed a small increase at the end of the experiment.

CONCLUSIONS

Ricin induces glomerular thrombotic microangiopathy, closely resembling that which occurs in verocytotoxin-producing E. coli-induced HUS. As in HUS, high concentrations of proinflammatory cytokines are present, which are probably a result of cytokine superinduction by the toxin.

A comparison of the effects of verocytotoxin-1 on primary human renal cell cultures

Infection with verocytotoxin-producing Escherichia coli causes haemolytic uraemic syndrome (HUS). Verocytotoxin-1 (VT1) is cytopathic to renal microvascular endothelial cells in culture, supporting the hypothesis that the vasculopathy of HUS is caused directly by the toxic action of VT1 on cells. We provide evidence that VT1 inhibits protein synthesis in primary cultures of glomerular epithelial cells (GE), cortical tubular epithelial cells (CTE) and mesangial cells (MC). Using 100 pg/ml of VT1 we saw a decrease in protein synthesis to 14.3+/-1.9% in vero cells (a primate cell line), 1.7+/-0.3% in GE, 0.9+/-0.4% in CTE and 74.8+/-1.3% in MC at 24 h. The human renal epithelial cells are at least as sensitive as vero cells to the protein synthesis inhibitory effects of VT1 if not more so. Cell viability decreased in all cultures as measured by MTT reduction, neutral red incorporation and lactate dehydrogenase release and followed the same pattern of susceptibility as for protein synthesis inhibition. However, unlike vero cells, death occurred without DNA fragmentation. Cell sensitivity was greatest in cells which bound more VT1.

Synthesis of L-2,3-trans-3,4-cis-Dihydroxyproline Building Blocks for Peptide Synthesis

L-2,3-trans-3,4-cis-N-Fluorenylmethoxycarbonyl-3,4-dihydroxy-3,4-O-isopropylidineproline (9) has been prepared from D-gulonolactone in nine steps and an overall yield of 22%. Compound 9 has been converted to its allyl ester 13. Compounds 9 and 13 were investigated as building blocks for the incorporation of dihydroxyproline into peptides, with compound 9 serving as a carboxyl component and compound 13 as a precursor to an amino component for peptide coupling reactions. Their utility was demonstrated by the synthesis of dipeptides 11 and 15.

An examination of the development of language in the normal child

The development of language remains a theoretical mystery in many respects. There are similarities in the work of developmental theorists, physiological theorists and anthropological studies. Knowledge of the normal language development process for paediatric nurses and allied professionals is essential in order to identify the abnormal and therefore ensure early intervention with support services and treatment. Further research from a universal perspective is advocated.

The late histologic findings in diarrhea-associated hemolytic uremic syndrome

Kidney biopsies were undertaken for persisting proteinuria 3.3 to 7 years (mean 5.4 years) from the onset of diarrhea-associated hemolytic uremic syndrome (D + HUS) in 5 boys and 2 girls (age at presentation mean 3.2 years, range 1.0 to 9.7 years). At 1 year the mean early morning urine protein/creatinine ratio was 100 mg/mmol, and the mean glomerular filtration rate was 65 mL/min/1.73 m2. At 5 years the mean early morning urine protein/creatinine ratio was 81 mg/mmol, and the mean glomerular filtration rate was 73 mL/min/1.73 m2. The biopsy specimens were compared with those of 7 age- and sex-matched children who were investigated for isolated persistent microscopic hematuria but in whom no abnormality was detected. Global glomerulosclerosis was noted in 6 patients with D + HUS, and 2 of these had segmental sclerosing lesions. Tubular atrophy and interstitial scarring were seen in all but 1 patients. The glomeruli in the D + HUS group were significantly larger than in the control group (P < .01). These findings are typically found in kidneys with reduced nephron numbers and are compatible with changes of hyperperfusion and hyperfiltration in surviving nephrons. Long-term follow-up of patients with D + HUS and proteinuria is advisable.

The integrated health professions education program seminar

Powerful dynamics of change require practitioners from all disciplines to be prepared to work in interdisciplinary teams, competently access health and information technologies, and understand the multiple functions required for adequate healthcare provision. The University of Iowa's Integrated Health Professions Program is a state-funded effort designed to provide students with a common educational experience to enable them to work collaboratively in underserved or rural settings. Students take part in a series of team-building seminars including technology-based instruction and activities in conjunction with visits to community clinical sites. The authors discuss the experiential, collaborative, and cooperative forms of learning that take place during the seminar series.

The prevalence and treatment of end-stage renal disease in an Asian child population

BACKGROUND

There are significant differences in the incidence and aetiology of end-stage renal disease (ESRD) between the Asian and white adult population in the UK. The aim of this study was to determine if similar differences occurred in the paediatric ESRD population.

METHODS

A retrospective study of children with ESRD presenting between 1980 and 1995 in the population served by the Birmingham Children's Hospital.

RESULTS

Asian children comprised 7.4% of the total child population (0-15 years). ESRD developed in 165 children (138 white, 27 Asian). The prevalence of ESRD for whites was 15 per 10(5) white child population and for Asians, 40 per 10(5) Asian child population. A genetic aetiology was noted in 26 (19%) whites and 12 (44%) Asians (P < 0.001). Of the 147 renal transplants, 22 (15%) were to Asian recipients. The distribution of blood groups in the two populations reflected the pattern in the respective general populations as a whole. There was no significant difference in time to transplantation for the two groups (whites, mean 6 months, 95% confidence interval 6-11 months; Asians, mean 7 months, 95% CI 4-12 months). Asian patients had significantly more mismatches (> or = 3 or > or = 4) compared to white patients.

CONCLUSIONS

Asian children had a higher prevalence of ESRD, with genetic disease predominating. Differences in ethnicity or blood group did not influence time to transplantation in those that received a transplant although Asians had more mismatches.

Mutations in the chloride channel gene, CLCNKB, cause Bartter's syndrome type III

Analysis of patients with inherited hypokalaemic alkalosis resulting from salt-wasting has proved fertile ground for identification of essential elements of renal salt homeostasis and blood-pressure regulation. We now demonstrate linkage of this phenotype to a segment of chromosome 1 containing the gene encoding a renal chloride channel, CLCNKB. Examination of this gene reveals loss-of-function mutations that impair renal chloride reabsorption in the thick ascending limb of Henle's loop. Mutations in seventeen kindreds have been identified, and they include large deletions and nonsense and missense mutations. Some of the deletions are shown to have arisen by unequal crossing over between CLCNKB and the nearby related gene, CLCNKA. Patients who harbour CLCNKB mutations are characterized by hypokalaemic alkalosis with salt-wasting, low blood pressure, normal magnesium and hyper- or normocalciuria; they define a distinct subset of patients with Bartter's syndrome in whom nephrocalcinosis is absent. These findings demonstrate the critical role of CLCNKB in renal salt reabsorption and blood-pressure homeostasis, and demonstrate the potential role of specific CLCNKB antagonists as diuretic antihypertensive agents.

Renal histopathology in fatal cases of diarrhoea-associated haemolytic uraemic syndrome. British Association for Paediatric Nephrology

Autopsy material was examined from British children dying early in the course of haemolytic uraemic syndrome (HUS). These presented after 1983, the period in which verocytotoxin-producing Escherichia coli (VTEC) infection was confirmed as the leading cause of diarrhoea-associated (D+HUS) in the United Kingdom. Of 18 cases referred for this study, 3 were found on review to have no history of a diarrhoeal prodrome (D-HUS). In the D+ patients, the median duration from onset of diarrhoea to death was 8 days (range 4-42 days). VTEC infection was confirmed in 6 cases. All had neutrophilia at presentation (median 21, range 15-49.8 x 10(9)/l). The 15 cases had uniform pathological features, consisting of glomerular thromboses and congested rather than ischaemic glomeruli. Arteriolar thromboses were common at the hilum of glomeruli and were sometimes also seen proximally, including in interlobular arteries. There were cortical infarcts in 5 cases with extensive thrombosis. Cases were demonstrated to have significantly greater numbers of neutrophils expressed per 100 glomeruli than controls, when counted using immunohistological stains to neutrophil elastase and CD15. This study showed uniformity of the renal changes in D+HUS and gave further evidence of the importance of neutrophils in the pathogenesis of the disease.

Cytokines in haemolytic uraemic syndrome associated with verocytotoxin-producing Escherichia coli infection

The proinflammatory cytokines tumour necrosis factor-alpha (TNF-alpha) interleukin (IL)-1 beta, IL-6, and IL-8 were measured in plasma and urine samples from 19 children with verocytotoxin-producing Escherichia coli (VTEC) induced haemolytic uraemic syndrome (HUS) and 30 controls. TNF-alpha was detected in the plasma of two cases and one control; IL-6 in the plasma of one, and the urine of two cases, and in the plasma of one control. IL-1 beta and IL-8 were each identified in eight of the 19 cases and in one and two controls respectively. Urinary IL-8 was found in seven cases, four of whom had plasma concentrations below the limit of detection suggesting renal secretion of this cytokine. Cytokine concentrations did not correlate with peripheral blood neutrophil count at onset of disease. These data confirm the systemic release of cytokines responsible for the coordination of acute inflammatory processes in some children with VTEC induced HUS.

Influence of hypoxia on vascular endothelial growth factor and chorionic gonadotrophin production in the trophoblast-derived cell lines: JEG, JAr and BeWo

Growth of trophoblast tissue in early pregnancy is rapid and accomplished in an unusually hypoxic environment. Hypoxia has been reported to upregulate mRNA production of vascular endothelial growth factor (VEGF), and VEGF receptors have been found on trophoblast cells. These observations suggest that VEGF may have an important role in early placentation. This study examines the influence of hypoxia on both the production of the VEGF message and protein and on the production of human chorionic gonadotrophin (hCG) protein by the cell lines JEG, JAr and BeWo. Cells were grown under normoxic and hypoxic conditions for 72 h. The average oxygen tension in the culture media of the hypoxic cultures (6-7 kPa) was significantly less than in the normoxic cultures (19-21 kPa). RNA was extracted and message for VEGF(121), VEGF(165) and VEGF(189) found in all cell lines by reverse transcription and the polymerase chain reaction (RT-PCR). These messages were upregulated by hypoxia; findings confirmed by competitive PCR for VEGF and expression of the house keeping gene GAPDH. hCG and VEGF were measured by immunoassay. Hypoxia resulted in an increase in VEGF production (P<0.05) but had inconsistent effects on hCG production. In some experiments the absolute concentrations of hCG and VEGF in the culture media were noted to be significantly correlated (r>0.5, P<0.05). In addition to its role in angiogenesis, VEGF may have direct effects on trophoblast cells encouraging proliferation and invasion. These effects may be regulated in part through oxygen supply and hCG.

Comparison of ribosome-inactivating proteins in the induction of apoptosis

The aim of this study was to evaluate the ability of verocytotoxin-1 (VT1), VT1 B chain alone, ricin and a hybrid toxin (RASTA2) consisting of ricin A chain linked to VT1 B chain to inhibit protein synthesis and to induce apoptosis. The lethal effects of the toxins were compared using vero cells (originating from green African monkey kidney tissue). As previously described cell death occurred through apoptosis which was quantified using the diphenylamine assay. DNA fragmentation was seen with VT1 at 10 pg/ml but there was no effect with B chain alone. Fragmentation with ricin was seen at 10 ng/ml and with RASTA2 at 1 ng/ml. Protein synthesis inhibition was measured by [(35)S]methionine incorporation. VT1 had an IC50 of 0.0024 ng/ml, B chain alone was ineffective at inhibiting protein synthesis. Ricin had an IC50 of 0.39 ng/ml and RASTA2 of 1.7 ng/ml. In vero cells the B chain of these toxins does not participate in cell killing.