In silico investigation of potential phytoconstituents against ligand- and voltage-gated ion channels as antiepileptic agents

The most promising anticonvulsant phytocompounds were explored in this work using docking, molecular dynamic (MD) simulation, and Molecular Mechanics-Poisson-Boltzmann Surface Area (MM-PBSA) approaches. A total of 70 phytochemicals were screened against α-amino-3-hydroxyl-5-methyl-4-isoxazole propionic acid (AMPA), N-methyl-d-aspartate (NMDA), voltage-gated sodium ion channels (VGSC), and carbonic anhydrase enzyme II (CA II) receptors, and the docking results were compared to the reference drug phenytoin. Amentoflavone displayed the highest affinity for AMPA and VGSC receptors, with docking scores of - 10.4 and - 10.1 kcal/mol, respectively. Oliganthin H-NMDA and epigallocatechin-3-gallate-CA II complexes showed docking scores of - 10.9 and - 6.9 kcal/mol, respectively. All four complexes depicted a high dock score compared to the phenytoin complex at the binding site of the corresponding proteins. The MD simulation investigated the stabilities and favorable conformation of apoproteins and ligand/reference-bound complexes. The results revealed that proteins AMPA, VGSC, and CA II were more efficiently stabilized by lead phytochemicals than phenytoin binding. Additionally, principal component analysis and MM-PBSA results suggested that these lead phytocompounds have good compactness and strong binding free energy. Further, physicochemical and pharmacokinetic studies revealed that these final lead phytochemicals would be suitable for oral intake, have sufficient intestinal permeability, and have the ability to cross the blood-brain barrier (BBB). Comprehensively, this study predicted amentoflavone as the best lead phytochemical out of the 70 anticonvulsant phytocompounds that can be used to treat epilepsy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03948-1.

Patient understanding of genetic information influences reproductive decision making in retinoblastoma

BACKGROUND

Retinoblastoma is the most common malignant tumour of the eye in childhood, with nearly all bilateral tumours and around 17% to 18% of unilateral tumours due to an oncogenic mutation in the RB1 gene in the germline. Genetic testing enables accurate risk assessment and optimal clinical management for the affected individual, siblings, and future offspring.

MATERIAL AND METHODS

We carried out the first UK-wide audit of understanding of genetic testing in individuals with retinoblastoma. A total of 292 individuals aged 16 to 45 years were included.

RESULTS

Patients with bilateral disease were significantly more likely to understand the implications of retinoblastoma for siblings and children. There was a significant association between not knowing the results of genetic testing or not understanding the implications and not having children, particularly in women. Surprisingly, this was also true for individuals treated for unilateral disease with a low risk of retinoblastoma for their offspring.

CONCLUSION

We are concerned that individuals may be making life choices based on insufficient information regarding risks of retinoblastoma and reproductive options. We suggest that improvement in transition care is needed to enable individuals to make informed reproductive decisions and to ensure optimal care for children born at risk of retinoblastoma.

Focal laser treatment in addition to chemotherapy for retinoblastoma

BACKGROUND

Retinoblastoma is the most common primary intraocular malignancy of childhood. Systemic chemotherapy is a common treatment for intraocular retinoblastoma, and laser treatment is used as adjuvant therapy during or immediately after chemotherapy courses in selected cases.

OBJECTIVES

To compare the effectiveness and safety of adding focal laser therapy to systemically-delivered chemotherapy in treating intraocular retinoblastoma.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 9), MEDLINE Ovid (1946 to 20 October 2016), Embase Ovid (1980 to 20 October 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 20 October 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch); searched 20 October 2016, ClinicalTrials.gov (www.clinicaltrials.gov); searched 20 October 2016, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 20 October 2016. We did not use any date or language restrictions in the electronic searches for trials.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs) of systemic chemotherapy with versus without adjuvant laser therapy for postequatorial retinoblastoma.

DATA COLLECTION AND ANALYSIS

We planned to use standard methodological procedures expected by Cochrane. We planned to meta-analyse the primary outcome, that is the proportion of eyes with recurrence of tumours within three years from treatment MAIN RESULTS: No studies met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

No evidence from randomised controlled trials was found to support or refute laser therapy in addition to systemic chemotherapy for postequatorial retinoblastoma.

An improved matrix separation method for characterization of ultrapure germanium (8N)

An improved matrix separation method has been described to characterize ultrapure germanium of 8N (99.999999%) purity. In this method, temperature of the reaction vessel in which in-situ generated chlorine gas reacts with germanium solid material directly is optimized to quantitatively remove Ge matrix from all its impurities. Optimized reaction temperature has been found to be 230±5°C. Recovery studies on more than 60 elements have been carried out at the optimized temperature. Recoveries of all the analytes except As, Se, Sn, Hg, Tl are found to be quantitative. The method has been examined for various amounts of Ge material and found to be suitable even for 10g of Ge sample and provides low parts per billion and trillion levels of process blanks. Determination of concentrations of impurities has been done by inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) and high resolution continuum source graphite furnace atomic absorption spectrometer (HR-CS-GFAAS). In the absence of certified reference materials for ultrapure germanium, accuracy of the proposed method is established by spike recovery tests. Precision of this method is found to vary from 7% to 50% for concentrations between 4 and 0.004ngg(-1). Limits of detection (LOD) for the target analytes are found to be between 6 and 0.011ngmL(-1) or 1.8-0.003ngg(-1) for the proposed procedure. The method has been successfully applied for that characterization of ultrapure germanium material of 8N purity.

Platelets from diabetic pigs exhibit hypersensitivity to thrombin

Responses of platelets from diabetic and diabetic-hyperlipidemic pigs were studied. Pigs were made diabetic with single dose of alloxan, which acts by selectively destroying insulin-producing pancreatic beta cells thus inducing type 1 diabetes. Pigs were kept for 1 or 12 wk, during which thrombin-induced aggregation was monitored in washed platelets. The platelets showed increased sensitivity to aggregation within 1 wk of induction of diabetes. Hyperlipidemia alone for 12 wk did not increase platelet hypersensitivity, but hyperlipidemia together with diabetes significantly increased thrombin-induced platelet aggregation. Because this hypersensitivity occurred in washed platelets, this characteristic appears to be independent of any contribution by plasma factors or other blood cells. The hypersensitivity of platelets from diabetic pigs correlated with decreased activity of mitogen-activated protein kinase. These studies offer the first evidence that platelet hyperactivity occurs during the early stages (within a week) of induction of diabetes in pigs and before manifestation of other cardiovascular problems.

Cloud Point Extraction of Trace Metals from Seawater and Determination by Electrothermal Atomic Absorption Spectrometry with Iridium Permanent Modifier

A simple method is described for preconcentration and separation of trace metals such as Ag, Co, Cr, Cu, Fe, Mn, Ni and Pb simultaneously from seawater using a cloud point extraction (CPE) procedure. Triton X-114 nonionic surfactant and ammonium pyrrolidine dithiocarbamate (APDC) have been used as an extraction medium and a chelating extractant, respectively. The amounts of Triton X-114 and APDC and the pH value necessary for extraction were carefully optimized. The preconcentration factor of about 200 is achieved for all the studied metals. Electrothermal atomic absorption spectrometry (ETAAS) with an Ir coated graphite tube as permanent chemical modifier has been used for determination. The limits of detection of Ag, Co, Cr, Cu, Fe, Mn, Ni and Pb were 0.003, 0.008, 0.003, 0.006, 0.015, 0.002, 0.009 and 0.01 ng ml-1, respectively. Certified reference materials such as CASS-4 and NASS-5 (seawater) and NIST-1640 (natural water) have been used for validation of the new method. The relative standard deviation (%) obtained for all the metals are in the range 0.8 - 3.6% for natural water and 11-25% for seawater materials, except for Co in NASS-5 for which it was 50%.

Relationship between 12/15-lipoxygenase and COX-2 in mesangial cells: potential role in diabetic nephropathy

The 12/15-lipoxygenase (12/15-LO) and cyclooxygenase-2 (COX-2) pathways of arachidonate metabolism have been implicated in the pathogenesis of diabetic nephropathy (DN). In this study, we evaluated whether there is an interplay between 12/15-LO and COX-2 pathways in mesangial cells (MC). We utilized MC, microdissected glomeruli and renal cortical tissues. Transfections with cDNAs or short hairpin RNAs (shRNAs) were performed to overexpress or knockdown 12/15-LO and COX-2, respectively. Reverse transcription-polymerase chain reactions and Western blotting were used for evaluating mRNA and protein expression, respectively. We observed that the expression of both 12/15-LO and COX-2 were increased in high glucose stimulated rat MC relative to normal glucose, and also in cortical tissues from diabetic db/db and streptozotocin-injected mice relative to corresponding control mice. Treatment of rat MC with the 12/15-LO product, 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE), significantly increased COX-2 expression as well as levels of the COX-2 product, prostaglandin E(2) (PGE(2)). Interestingly, treatment of rat MC with PGE(2) led to a reciprocal increase in 12/15-LO expression as well as levels of 12(S)-HETE. The 12/15-LO shRNA could significantly attenuate COX-2 protein expression and vice versa. Furthermore, COX-2 expression levels were lower in MC and glomeruli from 12/15-LO knockout mice relative to control. Conversely, mouse MC stably overexpressing 12/15-LO had greater levels of COX-2 expression relative to mock-transfected cells. These new results indicate for the first time that 12/15-LO and COX-2 pathways can cross-talk and activate each other in MC. These novel interactions may amplify their effects on the progression of DN.

A novel GJA8 mutation is associated with autosomal dominant lamellar pulverulent cataract: further evidence for gap junction dysfunction in human cataract

PURPOSE

To identify the gene responsible for autosomal dominant lamellar pulverulent cataract in a four-generation British family and characterise the functional and cellular consequences of the mutation.

METHODS

Linkage analysis was used to identify the disease locus. The GJA8 gene was sequenced directly. Functional behaviour and cellular trafficking of connexins were examined by expression in Xenopus oocytes and HeLa cells.

RESULTS

A 262C>A transition that resulted in the replacement of proline by glutamine (P88Q) in the coding region of connexin50 (Cx50) was identified. hCx50P88Q did not induce intercellular conductance and significantly inhibited gap junctional activity of co-expressed wild type hCx50 RNA in paired Xenopus oocytes. In transfected cells, immunoreactive hCx50P88Q was confined to the cytoplasm but showed a temperature sensitive localisation at gap junctional plaques.

CONCLUSIONS

The pulverulent cataract described in this family is associated with a novel GJA8 mutation and has a different clinical phenotype from previously described GJA8 mutants. The cataract likely results from lack of gap junction function. The lack of function was associated with improper targeting to the plasma membrane, most probably due to protein misfolding.

Increased expression of cyclooxygenase-2 in human pancreatic islets treated with high glucose or ligands of the advanced glycation endproduct-specific receptor (AGER), and in islets from diabetic mice

AIMS/HYPOTHESIS

The cyclooxygenase-2 (PTGS2, previously known as COX2) enzyme and its products, such as prostaglandin E(2) (PGE(2)), have been implicated in the pathogenesis of several inflammatory diseases including islet dysfunction under diabetic conditions. In this study we evaluated whether diabetic conditions in vitro, such as high-glucose (HG) culture or AGE, or in vivo in animal models of diabetes can induce PTGS2 expression and activity in pancreatic islets.

MATERIALS AND METHODS

Isolated human pancreatic islets were treated for 24 h with HG (25 mmol/l) or with S100b (5 mg/l), a specific ligand for the AGE-specific receptor. PTGS2 and cyclooxygenase-1 (PTGS1, previously known as COX1) mRNA, protein expression and product PGE(2) were analysed by RT-PCR, Western blots and specific enzyme immunoassay respectively. Islet PTGS2 production in animal models was assessed by immunofluorescence.

RESULTS

Treatment of human pancreatic islets with HG and S100b led to a three-five-fold induction of PTGS2 mRNA (p<0.001). PTGS2 protein and its product PGE(2) (351.4+/-13.05 fg/ml vs control 39.4+/-0.11 fg/ml) were also increased (p<0.001). Pretreatment with specific inhibitors demonstrated the involvement of protein kinase C and oxidant stress in S100b- and HG-induced PTGS2 expression. However, insulin secretion was not significantly altered by S100b. Double immunofluorescent staining showed increased PTGS2 production in pancreatic islets from diabetic mice relative to corresponding controls.

CONCLUSION/INTERPRETATION

These results show for the first time that diabetes as well as diabetic conditions such as AGE and HG in vitro can directly upregulate the expression of the inflammatory PTGS2 gene in pancreatic islets. This might contribute to the pathogenesis of islet dysfunction in diabetes.

Full-field ERG responses recorded with skin electrodes in paediatric patients with retinal dystrophy

PURPOSE

Assess ERG responses recorded with skin electrodes in children with retinal dystrophies.

METHOD

ERG responses were recorded using skin electrodes in 17 healthy children and 43 paediatric patients with retinal dystrophy. Subjects were aged 4-14 years. ERG responses were recorded to full-field stimuli similar to those recommended in the ISCEV standard. The type of retinal dystrophy was classified on the basis of standard clinical criteria and the ERG responses were compared with those of the age-matched controls.

RESULTS

ERG responses were abnormal in every patient. The specific type of ERG abnormality was also consistent with the clinical findings in the majority of patients. Rod responses were abnormal in every patient with a rod-cone dystrophy and cone responses were also abnormal in the majority of patients. Those patients with cone dystrophy or rod monochromatism had normal or near normal rod responses but sub-normal or absent cone responses. Patients with CSNB or XLRS had a sub-normal b-wave but normal amplitude a-wave.

CONCLUSION

ERGs can be recorded successfully with skin electrodes in paediatric patientsand responses can aid the diagnosis of the type of retinal dystrophy.

Long term effect of latanoprost on intraocular pressure in normal tension glaucoma

AIM

To determine the long term effect of latanoprost on the intraocular pressure (IOP) of patients with normal tension glaucoma (NTG).

METHODS

Newly diagnosed patients with NTG were recruited into the study and had their baseline IOPs measured hourly between 8 am and 5 pm using a handheld electronic Tonopen. Patients with fixation threatening field defects were placed immediately into the treatment group while those with non-fixation threatening field defects were randomised into either the treatment group or the control group (no treatment). Treatment consisted of once daily topical latanoprost 0.005%. After a minimum period of 6 months, the patients underwent a second period of IOP phasing.

RESULTS

76 newly diagnosed patients with NTG were recruited-26 had fixation threatening disease, 25 were randomised to treatment, and 25 randomised to the control group. The average duration of treatment was 11 months. The average and maximum diurnal IOP for the patients randomised to treatment were statistically significantly lower than for the control patients at follow up (p<0.05). The treated group as a whole demonstrated a 17% decrease in the average diurnal IOP and a 19% decrease in the maximum diurnal IOP when compared to baseline IOP. 41% of those treated achieved a decrease of at least 20%, but only 10% of patients achieved a decrease of at least 30%.

CONCLUSION

Latanoprost had a sustained hypotensive effect in eyes with NTG and 41% of treated patients achieved a reasonable response. However, in the majority of eyes with NTG, latanoprost monotherapy may be insufficient in producing a desirable 30% reduction in IOP.

Characterization of the G91del CRYBA1/3-crystallin protein: a cause of human inherited cataract

Congenital cataract is a leading cause of visual disability in children. Inherited isolated (non-syndromic) cataract represents a significant proportion of cases and the identification of genes responsible for inherited cataract will lead to a better understanding of the mechanism of cataract formation at the molecular level both in congenital and age-related cataract. Crystallins are abundantly expressed in the developing human lens and represent excellent candidate genes for inherited cataract. A genome-wide search of a five-generation family with autosomal dominant lamellar cataract demonstrated linkage to the 17p12-q11 region. Screening of the CRYBA1/3 gene showed a 3 bp deletion, which resulted in a G91del mutation within the tyrosine corner, that co-segregated with disease and was not found in 96 normal controls. In order to understand the molecular basis of cataract formation, the mutant protein was expressed in vitro and its unfolding and refolding characteristics assessed using far-UV circular dichroism spectroscopy. Defective folding and a reduction in solubility were found. As the wild-type protein did not refold into the native conformation following unfolding, a corresponding CRYBB2 mutant was genetically engineered and its refolding characteristics analysed and compared with wild-type CRYBB2. Its biophysical properties support the hypothesis that removal of the glycine residue from the tyrosine corner impairs the folding and solubility of beta-crystallin proteins. This study represents the first comprehensive description of the biophysical consequences of a mutant beta-crystallin protein that is associated with human inherited cataract.

A clinical and molecular genetic study of a rare dominantly inherited syndrome (MRCS) comprising of microcornea, rod-cone dystrophy, cataract, and posterior staphyloma

AIM

To phenotype and genetically map the disease locus in a family presenting with autosomal dominant microcornea, rod-cone dystrophy, cataract, and posterior staphyloma.

METHODS

Six affected and three unaffected members of the pedigree were examined. All individuals provided a history and underwent a full clinical examination with A-scan and B-scan ultrasonography and electrophysiological testing where appropriate. PCR based microsatellite marker genotyping using a positional candidate gene approach was then performed on DNA samples extracted from venous blood provided by each subject.

RESULTS

The disorder is inherited as an autosomal dominant trait with variable expressivity and has a complex phenotype. Affected individuals had bilateral microcornea, pulverulent-like lens opacities, a rod-cone dystrophy and posterior staphyloma (MRCS). Using a positional candidate gene approach, the authors have evidence suggestive of linkage of this disorder to a region on 11q13 within the nanophthalmos 1 (NNO1) genetic interval. The small family size militates against achieving a LOD score of 3, but the haplotype data and the position of the putative MRCS locus within a known nanophthalmos locus are suggestive of linkage. A candidate gene within this region (ROM1) was screened and no mutations were found in affected members of the family.

CONCLUSION

This rare developmental disorder has some phenotypic similarities to nanophthalmos and possibly maps to a locus within the genetic interval encompassing the NNO1 locus. Screening of candidate genes within this region continues.

Alpha-B crystallin gene (CRYAB) mutation causes dominant congenital posterior polar cataract in humans

Congenital cataracts are an important cause of bilateral visual impairment in infants. In a four-generation family of English descent, we mapped dominant congenital posterior polar cataract to chromosome 11q22-q22.3. The maximum LOD score, 3.92 at recombination fraction 0, was obtained for marker D11S898, near the gene that encodes crystallin alpha-B protein (CRYAB). By sequencing the coding regions of CRYAB, we found in exon 3 a deletion mutation, 450delA, that is associated with cataract in this family. The mutation resulted in a frameshift in codon 150 and produced an aberrant protein consisting of 184 residues. This is the first report of a mutation, in this gene, resulting in isolated congenital cataract.

Asymmetric synthesis of 2-azido-1-arylethanols from azido aryl ketone-beta-cyclodextrin complexes and sodium borohydride in water

beta-Cyclodextrin catalyses for the first time the asymmetric reduction of alpha-azido aryl ketones to corresponding alcohols of great significance using sodium borohydride in water. The azido group appeared to be the best fit among various groups studied. This asymmetric reduction using water as solvent overcomes many of the drawbacks in the existing methodologies.

Differential role of cytosolic phospholipase A2 in the invasion of brain microvascular endothelial cells by Escherichia coli and Listeria monocytogenes

Invasion of brain microvascular endothelial cells (BMECs) is a key step in the pathogenesis of meningitis due to Escherichia coli and Listeria monocytogenes. Although host cell actin cytoskeletal rearrangements are essential in BMEC invasion by E. coli K1 and L. monocytogenes, the underlying signaling mechanisms remain unclear. This study demonstrates that host cell cytosolic phospholipase A2 (cPLA2) contributes to E. coli K1 invasion of BMECs but not to L. monocytogenes invasion of BMECs. This difference was observed with 4-bromophenacyl bromide, a nonselective PLA2 inhibitor, and arachidonyl trifluoromethyl ketone, a selective cPLA2 inhibitor, and was confirmed with BMEC derived from cPLA2 knockout mice. Activation of cPLA2 leads to generation of intracellular arachidonic acid, which is metabolized via cyclooxygenase (COX) and lipo-oxygenase (LOX) pathways into eicosanoids. COX and LOX inhibitors also significantly inhibit E. coli K1 invasion of BMECs.

Signaling mechanisms of nuclear factor-kappab-mediated activation of inflammatory genes by 13-hydroperoxyoctadecadienoic acid in cultured vascular smooth muscle cells

Oxidatively modified low density lipoprotein (LDL) has been implicated in the pathogenesis of atherosclerosis. LDL oxidation may be mediated by several factors, including cellular lipoxygenases. The lipoxygenase product of linoleic acid, 13-hydroperoxyoctadecadienoic acid (13-HPODE), is a significant component of oxidized LDL and has been shown to be present in atherosclerotic lesions. However, the mechanism of action of these oxidized lipids in vascular smooth muscle cells (VSMCs) is not clear. In the present study, we show that 13-HPODE leads to the activation of Ras as well as the mitogen-activated protein kinases, extracellular signal-regulated kinase 1/2, p38, and c-Jun amino-terminal kinase, in porcine VSMCs. 13-HPODE also specifically activated the oxidant stress-responsive transcription factor, nuclear factor-kappaB, but not activator protein-1 or activator protein-2. 13-HPODE-induced nuclear factor-kappaB DNA binding activity was blocked by an antioxidant, N-acetylcysteine, as well as an inhibitor of protein kinase C. 13-HPODE, but not the hydroxy product, 13-(S)-hydroxyoctadecadienoic acid, also dose-dependently increased vascular cell adhesion molecule-1 promoter activation. This was inhibited by an antioxidant as well as by inhibitors of Ras p38 mitogen-activated protein kinase and protein kinase C. Our results suggest that oxidized lipid components of oxidized LDL, such as 13-HPODE, may play a key role in the atherogenic process by inducing the transcriptional regulation of inflammatory genes in VSMCs via the activation of key signaling kinases.

Phosphatidylinositol 3-kinase activation and interaction with focal adhesion kinase in Escherichia coli K1 invasion of human brain microvascular endothelial cells

Invasion of brain microvascular endothelial cells (BMEC) is a prerequisite for successful crossing of the blood-brain barrier by Escherichia coli K1. We have previously demonstrated the requirement of cytoskeletal rearrangements and activation of focal adhesion kinase (FAK) in E. coli K1 invasion of human BMEC (HBMEC). The current study investigated the role of phosphatidylinositol 3-kinase (PI3K) activation and PI3K interaction with FAK in E. coli invasion of HBMEC. PI3K inhibitor LY294002 blocked E. coli K1 invasion of HBMEC in a dose-dependent manner, whereas an inactive analogue LY303511 had no such effect. In HBMEC, E. coli K1 increased phosphorylation of Akt, a downstream effector of PI3K, which was completely blocked by LY294002. In contrast, non-invasive E. coli failed to activate PI3K. Overexpression of PI3K mutants Deltap85 and catalytically inactive p110 in HBMEC significantly inhibited both PI3K/Akt activation and E. coli K1 invasion of HBMEC. Stimulation of HBMEC with E. coli K1 increased PI3K association with FAK. Furthermore, PI3K/Akt activation was blocked in HBMEC-overexpressing FAK dominant-negative mutants (FRNK and Phe397FAK). These results demonstrated the involvement of PI3K signaling in E. coli K1 invasion of HBMEC and identified a novel role for PI3K interaction with FAK in the pathogenesis of E. coli meningitis.

Involvement of focal adhesion kinase in Escherichia coli invasion of human brain microvascular endothelial cells

Escherichia coli K1 traversal across the blood-brain barrier is an essential step in the pathogenesis of neonatal meningitis. We have previously shown that invasive E. coli promotes the actin rearrangement of brain microvascular endothelial cells (BMEC), which constitute a lining of the blood-brain barrier, for invasion. However, signal transduction mechanisms involved in E. coli invasion are not defined. In this report we show that tyrosine kinases play a major role in E. coli invasion of human BMEC (HBMEC). E. coli induced tyrosine phosphorylation of HBMEC cytoskeletal proteins, focal adhesion kinase (FAK), and paxillin, with a concomitant increase in the association of paxillin with FAK. Overexpression of a dominant interfering form of the FAK C-terminal domain, FRNK (FAK-related nonkinase), significantly inhibited E. coli invasion of HBMEC. Furthermore, we found that FAK kinase activity and the autophosphorylation site (Tyr397) are important in E. coli invasion of HBMEC, whereas the Grb2 binding site (Tyr925) is not required. Immunocytochemical studies demonstrated that FAK is recruited to focal plaques at the site of bacterial entry. Consistent with the invasion results, overexpression of FRNK, a kinase-negative mutant (Arg454 FAK), and a Src binding mutant (Phe397 FAK) inhibited the accumulation of FAK at the bacterial entry site. The overexpression of FAK mutants in HBMEC also blocked the E. coli-induced tyrosine phosphorylation of FAK and its association with paxillin. These observations provide evidence that FAK tyrosine phosphorylation and its recruitment to the cytoskeleton play a key role in E. coli invasion of HBMEC.

Nuclear activation and translocation of mitogen-activated protein kinases modulated by ethanol in embryonic liver cells

Activation and nuclear translocation of mitogen activated protein (MAP) kinases in ethanol-treated embryonic liver cells (BNLCL2) was investigated. The relative amount of MAPK proteins, MAP kinase activity and MAPK/LDH (lactate dehydrogenase) ratios were determined in nuclear and cytosolic fractions before and after serum stimulation. In ethanol-treated cells, serum-stimulated MAPK activation was potentiated in both cytosolic and nuclear fractions. Levels of both the p42 and p44 MAPK proteins increased in nuclear fractions from cells treated with ethanol alone for 24 h. Serum-stimulated nuclear translocation of both p42 and p44 MAPK was potentiated in ethanol-treated cells. Nuclear fractions from ethanol-treated cells had a modest increase in MAP kinase activity concurrent with the increased MAPK protein levels. The ratio of MAPK/LDH increased in nuclear fractions with increasing concentrations of ethanol and after serum stimulation. This further confirmed the nuclear translocation of MAPK and also demonstrated that it is not a non-specific effect of ethanol. These results demonstrate, for the first time, that in BNLCL2 liver cells ethanol treatment has dual effects. First, ethanol triggered nuclear translocation of MAPK without causing its activation. Second, it potentiated serum-stimulated activation and translocation of MAPK in the nucleus. These findings provide a novel mechanism through which ethanol may affect cellular and nuclear processes in liver cells.

Glaucoma awareness and screening uptake in relatives of people with glaucoma

PURPOSE

To assess glaucoma awareness and screening uptake in relatives of people with glaucoma.

METHODS

A questionnaire was administered to 52 patients with primary open-angle glaucoma. They were asked about their awareness of glaucoma clustering within families, and the need for glaucoma screening in relatives of glaucoma patients. Patients were asked to identify one or more first-degree relatives, aged over 40 years and thus eligible for free glaucoma screening in the United Kingdom. These relatives were mailed a similar questionnaire. In performing the statistical analysis we corrected for possible clustering within families. The study was approved in advance by our local ethics committee, and all participants were informed of the United Kingdom's free screening service afterwards.

RESULTS

Ninety relatives were identified, of whom 70 (78%) returned questionnaires. Only 53% of responding relatives thought they were at increased lifetime risk of developing glaucoma. Though 81% of relatives had been screened, many were screened infrequently. We compared the responses of patients' siblings and patients' offspring. Perceived lifetime glaucoma risk was similar in the two groups, but the (older) siblings had a significantly lower awareness of the free screening service (p = 0.03) and attended for screening less frequently (p = 0.07). Uptake of regular, free glaucoma screening at least every 2 years was 57% among offspring and 30% among siblings (p = 0.005). Because of selection bias (good communicators were more likely to be invited to participate) the true rates of glaucoma awareness and screening uptake are almost certainly lower than this.

CONCLUSIONS

Relatives of people with glaucoma should be made more aware of the need for glaucoma screening and encouraged to use the free screening service. Older relatives should be particularly targeted.

Activation of mitogen activated protein kinase in human platelets by genistein

Genistein, a putative tyrosine kinase inhibitor, stimulated human platelet mitogen activated protein kinase (MAPK) activity in a dose- and time-dependent manner. When MAPK was maximally stimulated by phorbol 12-myristate 13-acetate (PMA), genistein still elicited the increase in MAPK activity. Staurosporine (50 nm), significantly decreased the PMA-induced MAPK activity, but had little inhibitory effect on the genistein-induced MAPK activity. Both these observations indicated a protein kinase C (PKC) independent pathway for the genistein-stimulated MAPK activity. When other tyrosine kinase inhibitors (methyl-2,5-dihydroxycinnamate, and tyrphostin) were employed, similar increases in the MAPK activity were observed. Addition of genistein to cytosolic fraction of platelets had no effect on the MAPK activity and indicated that this effect is not due to direct physical interaction between genistein and MAPK and that intact platelets are required for it. MAPK activity of platelets from rabbit and pig was also stimulated by genistein. This effect of genistein was not observed in other cell types tested (BNLCL2, HEL and U937 cells). Forskolin, which increases cyclic AMP had little effect on the basal platelet MAPK activity or the genistein activated MAPK, while it decreased by half the PMA-induced MAPK activity. The inactive analog of genistein, daidzein, which does not inhibit tyrosine kinase had little effect on MAPK. Genistein caused a decrease in basal tyrosine phosphorylation of pp60(c-src) protein as detected with anti-phosphotyrosine (anti-PTyr) Ab. Thus, inhibition of basal tyrosine kinase results in an increase in MAPK activity. This study demonstrates for the first time a novel mechanism for regulation of MAPK in platelets in which inhibition of tyrosine kinase results in activation of MAPK, independent of PKC and cAMP pathways.

Vitreous haemorrhage in Fanconi's anaemia

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Potentiation of mitogen-activated protein kinase by ethanol in embryonic liver cells

Ethanol modulates agonist responses in liver cells, which are the major site of ethanol metabolism. Mitogen-activated protein kinases (MAPKs) are involved in the integration of multiple signaling pathways leading to cellular responses. However, the effect of ethanol on liver MAPK is not known. To this end, we studied the activation of MAPK in a normal mouse embryonic liver cell line (BNLCL2) after acute and chronic exposure to ethanol. Acute exposure to ethanol (0-400 mM) for 1 hr had no effect on either basal or serum- and phorbol-12-myristate-13-acetate (PMA)-stimulated MAPK activity. Chronic exposure to ethanol (0-400 mM) for 24 hr potentiated the stimulation of MAPK by serum, PMA, or thrombin. Maximum potentiation was observed with 200 mM ethanol (2- to 3-fold higher than control cells). Chronic exposure had no significant effect on epidermal growth factor-stimulated MAPK activity. In-gel MAPK assay of cytosolic extracts and of immunoprecipitates obtained with MAPK antibody demonstrated that ethanol potentiated the activation of both p42 and p44 MAPKs. When cells were pretreated with pertussis toxin, the potentiation by ethanol was abolished. It is concluded that ethanol potentiates MAPK in fetal liver cells by a pertussis toxin-sensitive G-protein-dependent mechanism.

The efficacy of neodymium: YAG laser iridotomy in the treatment of closed peripheral iridotomies in silicone-oil-filled aphakic eyes

Eighteen patients had a surgical inferior peripheral iridotomy performed to prevent pupil block and silicone oil anterior chamber prolapse. The occlusion of an iridotomy was treated by neodymium: YAG laser therapy and this form of treatment was successful only in 4 cases (22%). The reopening of occluded iridotomies is best performed by surgery as opposed to laser treatment.

Alterations in differentiation and behavior of monocytic phagocytes in transgenic mice that express dominant suppressors of ras signaling

To address the role of ras signaling in monocytic phagocytes in vivo, the expression of two dominant suppressors of in vitro ras signaling pathways, the carboxyl-terminal region of the GTPase-activating protein (GAP-C) and the DNA binding domain of the transcription factor ets-2, were targeted to this cell compartment. A 5-kb portion of the human c-fms proximal promoter was shown to direct expression of the transgenes to the monocytic lineage. As a result of the GAP-C transgene expression, ras-GTP levels were reduced in mature peritoneal macrophages by 70%. The terminal differentiation of monocytes was altered, as evidence by the accumulation of atypical monocytic cells in the blood. Mature peritoneal macrophages exhibited changes in colony-stimulating factor 1-dependent survival and structure. Further, expression of the colony-stimulating factor 1-stimulated gene urokinase plasminogen activator was inhibited in peritoneal macrophages. The results indicate that ras action is critical in monocytic cells after these cells have lost the capacity to traverse the cell cycle.

Opposing actions of c-ets/PU.1 and c-myb protooncogene products in regulating the macrophage-specific promoters of the human and mouse colony-stimulating factor-1 receptor (c-fms) genes

The receptor for macrophage colony stimulating factor (CSF-1), the c-fms gene product, is a key determinant in the differentiation of monocytic phagocytes. Dissection of the human and mouse c-fms proximal promoters revealed opposing roles for nuclear protooncogenes in the transcriptional regulation of this gene. On the one hand, c-ets-1, c-ets-2, and the macrophage-specific factor PU.1, but not the ets-factor PEA3, trans-activated the c-fms proximal promoter. On the other hand c-myb repressed proximal promoter activity in macrophages and blocked the action of c-ets-1 and c-ets-2. Basal c-fms promoter activity was almost undetectable in the M1 leukaemia line, which expressed high levels of c-myb, but was activated as cells differentiated in response to leukemia inhibitory factor and expressed c-fms mRNA. The repressor function of c-myb depended on the COOH-terminal domain of the protein. We propose that ets-factors are necessary for the tissue-restricted expression of c-fms and that c-myb acts to ensure correct temporal expression of c-fms during myeloid differentiation.

Cardiac operations in patients with end-stage renal disease

Factors influencing the survival of 35 consecutive patients in end-stage renal disease who required 40 open heart surgical procedures over the past 8 years were studied. The mean age in these patients was 57.7 +/- 3 years (range, 32 to 77 years); 74.3% of the patients were male; and the average duration of hemodialysis was 3.6 +/- 0.6 years. Twenty-nine myocardial procedures (20 of 29 for unstable angina), six valve replacements, and five combined procedures were performed. The actuarial survivals at 1 and 3 months, and at 1, 5, and 8 years were 90%, 85%, 76%, 55%, and 43%, respectively. Based on the results of univariate analysis, the most significant predictor of both early and late mortality was New York Heart Association (NYHA) class IV congestive heart failure. The 5-year survival in the patients 60 years and older was less favorable than that in patients younger than 60 years (45% versus 63%) (p < 0.05). The 5-year survival in the patients in NYHA class IV was only 27%, as compared to 63% in the patients in class II or III (p < 0.001). All survivors have remained free of angina and 19 of the 21 survivors showed an improvement in their NYHA class. Four patients under 40 years of age have subsequently been able to undergo renal transplantation. Overall, these results justify proceeding with an open heart surgical procedure in dialysis patients, when needed, but before the onset of congestive heart failure.

An enhancer element responsive to ras and fms signaling pathways is composed of two distinct nuclear factor binding sites

In order to precisely define the sequences that constitute the ras-responsive enhancers element present in the murine retrotransposon NVL3, point mutations were introduced into the previously defined minimal transcriptional enhancer DNA. Analyses of the effects of these point mutations in transient transfection experiments, in gel retention assays, and by methylation interference footprinting indicated that the enhancer element was composed of two binding sites for distinct nuclear factors. Both binding sites were required for activation of the enhancer by either ras or v-fms oncogenes, and the distinct nuclear factors were found in extracts from cells that contained either oncogene. UV cross-linking analysis revealed that the AP1-related binding site, TGACTCT, was recognized by a nuclear factor of apparent molecular size of 50 kilodaltons, that is probably c-jun. The other binding site, CAGGATAT, is very similar to sites recognized by the ets-family of transcription factors, and was recognized by the 120-kilodalton ras-responsive factor-1. Activation of the NVL3 element was reconstituted in an in vitro transcription assay. The ets-related binding site was necessary for this in vitro reconstitution of activity. Thus, the NVL3 enhancer is related to the previously described oncogene-responsive enhancer element present in polyoma virus and is also related to elements identified in several cellular genes known to be ras-responsive, including the transforming growth factor-beta 1 gene.

Cloning and characterization of the Azotobacter vinelandii recA gene and construction of a recA deletion mutant

The recA gene of Azotobacter vinelandii was isolated from a genomic library by heterologous complementation of an Escherichia coli recA mutation for resistance to UV radiation. The A. vinelandii recA gene was localized on adjacent PstI fragments of 1.3 and 1.7 kb. The cloned A. vinelandii recA gene was functionally analogous to the E. coli recA gene. It was also able to complement the E. coli recA mutation for homologous recombination. A recA deletion mutant of A. vinelandii was constructed. This mutant was sensitive to DNA-damaging agents like UV rays, methyl methane sulfonate (MMS) and nalidixic acid and was deficient in homologous recombination.

Multiple chromosomes of Azotobacter vinelandii

The number of copies of the genes leuB, nifH, nifD, and nifK per cell of Azotobacter vinelandii has been determined to be about 80. A beta-lactamase gene was integrated into the A. vinelandii chromosome by single-point crossover. Subsequently, we have been able to detect nearly 80 copies of this beta-lactamase gene per cell of A. vinelandii when cultured for a large number of generations in the presence of ampicillin. The multiple copies of the beta-lactamase gene do not seem to be present on a single chromosome, as evident from the fragment obtained by digestion of cellular DNA with the appropriate restriction endonuclease. The kinetics of renaturation of DNA of A. vinelandii is suggestive of complexity similar to that of Escherichia coli. The DNA content of A. vinelandii, however, is 40 times that of E. coli. All these indicate the presence of multiple chromosomes, possibly as many as 80, in A. vinelandii.

Characterization of the gene for the Fe-protein of the vanadium dependent alternative nitrogenase of Azotobacter vinelandii and construction of a Tn5 mutant

A sequence homologous to the conventional nifH gene has been cloned from a different region of the Azotobacter vinelandii genome. Tn5 insertions were obtained in this clone and the mutagenized plasmid was used for marker exchange with A. vinelandii strain CA12 (delta nifHDK) to obtain Tn5 mutants. These mutants exhibited a Nif- phenotype in the presence of vanadium, unlike CA12 which was Nif+ on vanadium-containing medium. The gene in the cloned nifH-like region is therefore apparently involved in the vanadium dependent alternative pathway of nitrogen fixation. This gene, nifH2, has been sequenced and encodes a protein of 289 amino acids that is similar to nifH in nucleotide sequence, deduced amino acid sequence, predicted secondary structure and hydrophobicity profile. A second open reading frame downstream of nifH2 codes for a protein of 64 amino acids, similar to the ferredoxin (Fd)-like protein encoded downstream of nifH* in A. chroococum. Sequence analysis suggests that the nifH2 and Fd-like genes are in a single operon.

Rehabilitation and long-term management of the spinal cord injured adult

Rehabilitation and long-term care of the spinal cord injured adult must be oriented toward prevention, be patient and family centered, and transcend all geographic settings. The nurse is a key coordinator and provider of care, as well as a facilitator of patient adaptation. The nurse involved in the care of the spinal cord injured adult must be knowledgeable in the rehabilitation and long-term care considerations essential to the reintegration and well-being of this population.