Posterior Reversible Leucoencephalopathy Syndrome: Case Series, Comments, and Diagnostic Dilemma

PURPOSE OF REVIEW

To report a series of patients with clinical and radiological features suggestive of posterior reversible encephalopathy syndrome (PRES) related to diverse etiologies emphasizing its pathophysiological basis.

RECENT FINDINGS

Posterior reversible encephalopathy syndrome (PRES) may present with a broad range of clinical symptoms from headache and visual disturbances to seizure and altered mentation. Typical imaging findings include posterior-circulation predominant vasogenic edema. Although there are many well-documented diseases associated with PRES, the exact pathophysiologic mechanism has yet to be fully elucidated. Generally accepted theories revolve around disruption of the blood-brain barrier secondary to elevated intracranial pressures or endothelial injury induced by ischemia from a vasoconstrictive response to rising blood pressure or toxins/cytokines. While clinical and radiographic reversibility is common, long-standing morbidity and mortality can occur in severe forms. In patients with malignant forms of PRES, aggressive care has markedly reduced mortality and improved functional outcomes. Various factors that have been associated with poor outcome include altered sensorium, hypertensive etiology, hyperglycemia, longer time to control the causative factor, elevated C reactive protein, coagulopathy, extensive cerebral edema, and hemorrhage on imaging. Reversible cerebral vasoconstriction syndromes (RCVS) and primary angiitis of the central nervous system (PACNS) are invariably considered in the differential diagnosis of new cerebral arteriopathies. Recurrent thunderclap headache (TCH), and single TCH combined with either normal neuroimaging, border zone infarcts, or vasogenic edema, have 100% positive predictive value for diagnosing RCVS or RCVS-spectrum disorders. Diagnosis of PRES in some circumstances can be challenging and structural imaging may not be sufficient to distinguish it from other differential diagnostic considerations like ADEM. Advanced imaging techniques, such as MR spectroscopy or positron emission tomography (PET) can provide additional information to determine the diagnosis. Such techniques are more useful to understand the underlying vasculopathic changes in PRES and may answer some of the unresolved controversies in pathophysiology of this complex disease. Eight patients with PRES resulting from different etiologies varying from pre-eclampsia/eclampsia, post-partum headache with seizures, neuropsychiatric systemic lupus erythematosus, snake bite, Dengue fever with encephalopathy, alcoholic liver cirrhosis with hepatic encephalopathy, and lastly reversible cerebral vasoconstriction syndrome (RCVS). Additionally, a diagnostic dilemma between PRES and acute disseminated encephalomyelitis (ADEM) was notable in one patient. Some of these patients did not have or only very transiently had arterial hypertension. PRES may underlie the clinical conundrum of headache, confusion, altered sensorium, seizures, and visual impairment. PRES need not necessarily be always associated with high blood pressure. Imaging findings may also be variable. Both clinicians and radiologists need to familiarize themselves with such variabilities.

A video-based discussion of movement disorders in paediatric anti NMDAR encephalitis: A case series from Eastern India

PURPOSE

The spectrum of movement disorders associated with anti N-Methyl-d-Aspartate-Receptor (NMDAR) encephalitis is myriad, particularly in children, possibilities of which were investigated from two tertiary care centres.

METHODS

A retrospective study was conducted in two tertiary referral centres in Eastern India, analysing data of 8 paediatric patients diagnosed as anti NMDAR encephalitis, presenting with one or more movement disorders (MDs).

RESULTS

All the patients were of Bengali ethnicity with a median age of 9 years (3-16 years) and with female predilection (62.5%). CSF pleocytosis was a common feature in all. Seizures were described in 62.5%% of patients with a solitary patient exhibiting abnormalities on brain imaging. 3 out of 8 (37.5%) of patients presented with a single MD while the remaining had more than one type. Oro-linguo-facial dyskinesias and dystonia (37.5% each) were the most common movement type followed by chorea (12.5%). Complex stereotypies, myoclonus and facial tics were noted in one patient each. All patients received pulse methyl prednisolone. Escalation to second line therapy in form of rituximab was done for 5 patients (62.5%). Following immunotherapy, hyperkinetic movements resolved in 50% of patients, with persistence of movements in one (12.5%). A mortality of 37.5% was noted. Median duration of follow up was 26 months, during which none of the patients had evidence of systemic neoplasm.

CONCLUSION

MDs are a core feature of anti NMDAR encephalitis, particularly in the paediatric age group, understanding and characterization of which, is the key to early diagnosis and effective therapy.

Correlation of ATP7B gene mutations with clinical phenotype and radiological features in Indian Wilson disease patients

INTRODUCTION

Wilson disease (WD) is characterized by a wide variety of clinical manifestations. Our study aimed to correlate genotype with clinical and radiological features in Indian WD patients.

METHODS

We conducted a descriptive observational study in a tertiary care neurology referral center of eastern India over a period of 2 years. Demographic data collection, clinical examination and relevant investigations were done for all WD patients meeting the inclusion criteria. Based on previous reports of mutation hotspots for WD in Eastern India, we performed PCR-Sanger sequencing of selected exons of ATP7B gene. To understand the role of each of these covariates on the occurrence of common mutation, we applied a logistic regression as well as random forest in a supervised learning framework.

RESULTS

Fifty-two WD patients were included in the study. c.813C > A (p.C271X) was the commonest identified mutation. The statistical methods applied to our data-set reveal the most important features for predicting common mutation or its absence. We also found that the state-of-the-art classification algorithms are good at predicting the absence of common mutation (with true positive rates being 0.7647 and 0.8823 for logistic classifier and random forest, respectively), but predicting the occurrence remains a harder modeling challenge.

CONCLUSIONS

WD patients in eastern India have significant genotypic and phenotypic diversity. Statistical methods for binary classification show some early promise of detecting common mutations and suggest important covariates, but further studies with larger samples and screening of remaining exons are warranted for understanding the full genetic landscape of Wilson disease.

Adult-onset Kawasaki disease: A great masquerader

Kawasaki disease is a necrotising small-to-medium vessel vasculitis affecting children between age groups of 6 months and 5 years. Following the first description in Japanese infants, it has been recognised as the single most common cause of non-infectious vasculitis in children worldwide. Presentation in adult age groups, although described, is rare. Herein, we report a case about a 19-year-old female Indian patient diagnosed with Kawasaki disease and managed with antiplatelets and intravenous immunoglobulin, without further sequalae. We aim to highlight the importance of recognising this entity in adult age groups in day-to-day clinical practice.

Charcot-Marie-Tooth disease type 4J with spastic quadriplegia, epilepsy and global developmental delay: a tale of three siblings

Charcot-Marie-Tooth (CMT) disease is mainly a disease of peripheral nervous system and patients typically present with features of demyelinating neuropathy or axonal neuropathy or both. Rarely patients present with features of central nervous system involvement. Parkinsonism, aphemia and familial epilepsy syndrome have previously come up as case reports in association with CMT type 4 J.We hereby describe a family with 3 siblings affected with CMT4J with homozygous FIG4 mutation who presented with global developmental delay, epilepsy and spastic quadriparesis.

Neurological manifestations in children with dengue fever: an Indian perspective

Ours was a descriptive observational cross-sectional study carried out in a tertiary care hospital in eastern India over a period of one year to study the profile of neurological involvement in paediatric dengue patients. Of 71 laboratory-confirmed cases, 20 (28.17%) had neurological involvement. Common forms observed were acute encephalopathy (40%), encephalitis (30%), pure motor weakness (15%), transverse myelitis (5%), acute disseminated encephalomyelitis (5%) and Guillain–Barré syndrome (5%). The dengue IgM antibody could be detected in the cerebrospinal fluid of only two patients with encephalitis. Neurological involvement was present in all four patients who died during the study period (two-tailed P value = 0.005).

Penile Length and Testicular Volume in Newborns

OBJECTIVES

To measure Penile length (PL) and Testicular volume (TV) in newborn boys for assessing genital abnormalities.

METHODS

In a tertiary care setting, measurements of PL and TV were recorded from 480 babies born on alternate days except the weekend, at 24 to 72 h of life by one investigator with the same set of instruments. The penis was stretched to the point of increased resistance and the distance from the tip of the glans penis to the pubic ramus was measured as the stretched PL. Testicular volume was measured by a Prader orchidometer. Improvised beads made of plasticine were used for recording volumes <1 ml.

RESULTS

In the study cohort, 365 (76.04 %) were term babies. The mean PL was 34 ± 4.7 mm for the whole cohort while the corresponding value for mean TV was 0.6 ± 0.2 ml. The gestation age-wise percentile charts of PL and TV have been generated. There was modest positive correlation between PL and TV. Positive correlation was also observed between PL and TV and birth weight, body length, and head, chest and arm circumference. Both PL and TV showed statistically significant increase with gestational age. By the index data, the cut-off for suspecting abnormal penile length should be <24.5 or >45.5 mm for term babies.

CONCLUSIONS

The normative values generated can serve as reference standard in the diagnosis of penile length abnormalities in Indian babies and in clarifying issues of ambiguous genitalia and maldevelopment of male external genitalia.

Evaluation of malnutrition as a predictor of adverse outcomes in febrile neutropenia associated with paediatric haematological malignancies

AIM

Malnutrition has been reported in the literature to be adversely associated with outcomes in paediatric malignancies. Our objective in this paper was to evaluate malnutrition as a potential predictor for adverse outcomes in febrile neutropenia associated with haematological malignancies.

METHODS

A prospective observational study was performed in a tertiary care teaching hospital of Kolkata, India. Forty-eight participants, suffering from haematological malignancy, were included. Participants were included if they experienced at least one episode of febrile neutropenia. For children aged <5 years, weight for height, height for age and weight for age were used as criteria for defining malnutrition, while body mass index for age was used in children ≥5 years. A total of 162 episodes of febrile neutropenia were studied.

RESULTS

Thirty patients (30/48, 62.5%) included in the study had malnutrition. In bivariate analyses at patient level, there is a strong association between malnutrition and death (odds ratio (OR) 7.286, 95% confidence interval (CI) 0.838-63.345, one-tailed P = 0.044), and life-threatening complications show a moderate trend towards significance (OR 3.333, 95% CI 0.791-14.052, one-tailed P = 0.084). Survival functions were significantly different between malnourished and non-malnourished children (log rank test χ(2)  = 4.609, degree of freedom = 1, P = 0.032). Wasting was associated with life-threatening complications in children aged <5 years (OR 14, 95% CI 1.135-172.642, one-tailed P = 0.036). Logistic regression analyses at episode level revealed that phase of treatment and respiratory system involvement were significant predictors of death, while malnutrition was not.

CONCLUSION

Malnutrition may be a potential predictor of mortality in febrile neutropenia.

Deep vein thrombosis associated with dengue fever

BACKGROUND

Hemorrhagic manifestations are common with Dengue but thrombotic events are uncommonly reported.

CASE CHARACTERISTICS

11-year-old boy who presented with ileo-femoral deep vein thrombosis associated with serologically confirmed infection with DEN1 dengue virus.

OBSERVATION

There was no other history or investigation suggestive of a procoagulant state.

OUTCOME

Successfully treated with enoxaparin and warfarin.

MESSAGE

Thrombotic complications are possible with dengue infection.

Effects of Surface Preparation on Epitaxial GaN on 6H-SiC Deposited Via MOCVD

A comparison was made of 6H-SiC surfaces etched with H2, C2H4/H2, and HCl/H2, and the resulting crystal quality of epitaxial GaN films deposited on these substrates. To remove the many fine scratches and to smooth the rough surfaces typical of commercial SiC substrates, the Si-face 6H-SiC substrates were etched in H2, C2H4/H2, and HCl/H2 at 145 °C. GaN was subsequently deposited on these etched surfaces after first depositing a low temperature GaN buffer layer via metalorganic chemical vapor deposition (MOCVD). The surface morphologies after etching and after GaN deposition were characterized by atomic force microscopy and Normaski differential interference contrast microscopy, while the crystal quality of the GaN films was assessed by double crystal x-ray rocking curves and x-ray topography. 6H-SiC substrate surfaces were improved in terms of the removal of scratches and the reduction of surface roughness, and both surface morphology and crystal quality of the subsequently deposited GaN films were enhanced. However, the dislocation density was not decreased by the surface etching. The best GaN film was produced by etching the substrate in pure H2 for 40 minutes before growth. Recommendations for the optimum substrate treatment are made.

Role of Enteric Supplementation of Probiotics on Late-onset Sepsis by Candida species in Preterm Low Birth Weight Neonates: A Randomized, Double Blind, Placebo-controlled Trial

Background:

The increase in invasive fungal infections (IFIs) in neonatal intensive care unit (NICU) is jeopardizing the survival of preterm neonates. Probiotics modulating the intestinal microflora of preterm neonates may minimize enteral fungal colonization.

Aims:

This study was to examine whether probiotic supplementation in neonates reduced fungal septicemia.

Materials and Methods:

This prospective, randomized, double blind trial investigating the supplementation of preterm infants with a probiotic was done from May 2012 to April 2013, with 112 subjects randomized into two groups. Primary outcome: Decreased fungal colonization in gastrointestinal tract. Others: Incidence of late onset septicemia; duration of the primary hospital admission; number of days until full enteral feeds established.

Results:

Full feed establishment was earlier in probiotics group compared to placebo group (P = 0.016). The duration of hospitalization was less in the probiotic group (P = 0.002). Stool fungal colonization, an important outcome parameter was 3.03 ± 2.33 × 10⁵ colony formation units (CFU) in the probiotics group compared to 3 ± 1.5 × 10⁵ CFU in the placebo group (P = 0.03). Fungal infection is less in the study group (P = 0.001).

Conclusion:

The key features of our study were reduced enteral fungal colonization, reduce invasive fungal sepsis, earlier establishment of full enteral feeds, and reduced duration of hospital stay in the probiotics group.

A Visual Basic simulation software tool for performance analysis of a membrane-based advanced water treatment plant

A Visual Basic simulation software (WATTPPA) has been developed to analyse the performance of an advanced wastewater treatment plant. This user-friendly and menu-driven software is based on the dynamic mathematical model for an industrial wastewater treatment scheme that integrates chemical, biological and membrane-based unit operations. The software-predicted results corroborate very well with the experimental findings as indicated in the overall correlation coefficient of the order of 0.99. The software permits pre-analysis and manipulation of input data, helps in optimization and exhibits performance of an integrated plant visually on a graphical platform. It allows quick performance analysis of the whole system as well as the individual units. The software first of its kind in its domain and in the well-known Microsoft Excel environment is likely to be very useful in successful design, optimization and operation of an advanced hybrid treatment plant for hazardous wastewater.

Profile of hepatic involvement by dengue virus in dengue infected children

Background:

The spectrum of liver dysfunction in children with dengue infection is wide and has been associated with disease severity.

Aims:

This study was undertaken to estimate the range of hepatic involvement in dengue infection in children.

Materials and Methods:

This study assessed the biochemical and clinical profile of hepatic involvement by dengue virus in 120 children with serologically positive dengue fever (DF), aged 2 months to 14 years.

Results:

All cases were grouped into DF without warning signs (Group 1), DF with warning signs (Group 2) and severe dengue (Group 3) according to revised World Health Organization 2009 criteria. The spectrum of hepatic manifestations included hepatomegaly (80.8%), hepatic tenderness (46.3%), jaundice (60%), raised aspartate transaminase (AST), alanine transaminase (ALT) and prolonged prothrombin time (41.7%) and reduced serum albumin (56%).

Conclusions:

Hepatic dysfunction was observed more in Groups 2 and 3. There was 84.4% and 93.75% ALT and AST elevation respectively in Group 2 and 94.5% and 95.9% ALT and AST elevation respectively in Group 3 and fulminant hepatic failure was observed in Group 3. Therefore in a child with fever, jaundice, hepatomegaly and altered liver function tests, the diagnosis of dengue infection should be strongly considered in areas where dengue infection is endemic.

Granulocyte Colony-stimulating Factor for Preterms with Sepsis and Neutropenia: A Randomized Controlled Trial

Background:

Bacterial sepsis is one of the major causes of mortality in newborn infants. Mortality increases when sepsis is associated with neutropenia.

Materials and Methods:

We conducted a prospective, randomized, double-blind, placebo-controlled trial of recombinant human granulocyte colony-stimulating factor on preterm neonates (gestational age (GA) <34 weeks) with sepsis and absolute neutrophil count (ANC) of <1500 cells/mm³. Mortality, duration of Neonatal Intensive Care Unit (NICU) stay, hematological parameters (ANC, platelet count, and total leukocyte count) were compared between the two groups. The GCSF group (n=39) received GCSF intravenously in a single daily dose of 10 μg/kg/day in a 5% dextrose solution over 20-40 min for three consecutive days, while the control group (n=39) received placebo of an equivalent volume of 5% dextrose.

Results:

Baseline demographic profile among the two groups was comparable. Mortality rate in the GCSF group was significantly lower than in the control group (10% vs. 35%; P<0.05). By day 3 of treatment, ANC in the GCSF group was significantly higher (3521±327) compared to 2094±460 in the control group, with P value being <0.05. Duration of NICU stay also decreased significantly in the GCSF group.

Conclusion:

The administration of GCSF in preterms with septicemia and neutropenia resulted in lower mortality rates. Further studies are required to confirm our results and establish this adjunctive therapy in neonatal sepsis.

Disseminated Tuberculosis Causing Pancytopaenia in an Indian Boy

Tuberculosis still remains a major public health problem, particularly in developing countries. We report 11 year old Indian boy who presented with low grade fever, weight loss, hepatomegaly, ascites and petechial spots for past 6 weeks associated with pancytopaenia. Subsequently, bone marrow biopsy from the iliac crest revealed an epithelioid cell granuloma with hypercellularity. This is a rare presentation where disseminated tuberculosis presented as pancytopaenia. DOI: http://dx.doi.org/10.3126/jnps.v33i1.7577 J Nepal Paediatr Soc. 2013;33(1):52-54

Blood glutathione peroxidase and selenium in abortion

This study was carried out to estimate the levels of glutathione peroxidase and selenium in blood of abortion cases. Glutathione peroxidase and selenium were determined in 52 abortion cases (22 in 1(st) trimester, 30 in second trimester), 45 normal pregnant cases and 25 nonpregnant control cases. The selenium concentration in whole blood and plasma in abortion cases was almost the same as in normal pregnant women but significantly low when compared with the control non-pregnant group. The glutathione levels was higher in abortion cases when compared with normal pregnant and non-pregnant control groups. Red cell and plasma glutathione peroxidase activities of women who had abortion were significantly lower compared with both non-pregnant control group and normal pregnancies.

Synthesis of mesoporous silica nanoparticles and drug loading of poorly water soluble drug cyclosporin A

Mesoporous silica nanoparticles (MSNs) are introduced as chemically and thermally stable nanomaterials with well-defined and controllable morphology and porosity. It is shown that these particles possess external and internal surfaces that can be selectively functionalized with multiple organic and inorganic groups. Silica nano-particles were synthesized by chemical methods from tetraethylorthosilicate (TEOS), methanol (CH3OH) and deionised water in the presence of sodium hydroxide as catalyst at 80°C temperature. The nature and morphology of particles was investigated by scanning electron microscopy (SEM), N2 adsorption/desorption method using BET instrument and X-ray diffraction (XRD). Silica nanoparticles are applicable to a wide range of therapeutic entities from small molecule to peptides and proteins including hydrophobic and hydrophilic entities. Drug loading does not require chemical modification of the molecule; there are no changes in the drug structure or activity after loading and subsequent release of the drug. Thus, well suited to solve formulation problems associated with hydrophobic drugs such as peptide and protein drugs like cyclosporine A. Silica nanoparticles improved the solubility of poorly water soluble drugs and enhanced the absorption and bioavailability of these compounds.

Formulation, process development and evaluation of artemether and lumefantrine soft gelatin capsule

Artemether and Lumefantrine capsules are indicated for the treatment of P. falciparum malaria cases resistant to both chloroquine and sulphadoxine, pyrimethamine combination. Both artemether and lumefantrine act as blood schizontocides. Artemether is a sesquiterpene lactone derived from artemisinin. Artemisinin is a compound derived from the sweet wormwood plant and has been used for centuries in traditional Chinese medicine to treat fever. Lumefantrine is a synthetic aryl-amino alcohol antimalarial (quinine, mefloquine and halofantrine are members of the same group). Artemether is absorbed fairly rapidly with peak plasma concentrations reached about 2 hours after dosing. Absorption of lumefantrine, a highly lipophilic compound, starts after a lag period of up to 2 hours, with peak plasma concentration about 6-8 hours after dosing. In order to overcome this problem, we have observed that when the drug is given in the soft gelatin dosage form, the bioavailability of the drug is increased. Thus, increasing the absorption of the drug and peak plasma concentration is reached earlier then the conventional dosage form.

Formulation and evaluation of transparent ibuprofen soft gelatin capsule

The compound ibuprofen, 2-(4-isobutylphenyl) propionic acid, has been known e.g. from Martindale, the Extra Pharmacopoeia, 28^th edition, 1982, p.256, as a drug which had anti-inflammatory and analgesic properties. It is used for the treatment of rheumatoid arthritis or other inflammatory diseases of joints, soft tissue rheumatism and gout. Ibuprofen, because of its analgesic properties, has been widely used as anodyne, e.g. against pain or discomfort associated with headache, toothache or menstruation.

A medication suitable to combat acute pain is demanded to display its effects fast which action, in turn, is only achieved by a quick release and good bio-availability of the active-ingredient. It is for the commercial forms in particular that the conditions of preparation must be strictly observed, as minor alterations in production procedures such as mixing, pressure of compression and type of machine will affect the physical properties of the particles of he active ingredient and will deteriorate its bio-availability. It is an object of this presentation to provide a medicament that can be readily taken that contains an active amount of ibuprofen in a carrier, that is simple to prepare and that will quickly display a high activity.

Analysis of the Strain Profile in Thin Au/Ni Multilayers by X-Ray Diffraction

A dynamical x-ray diffraction theory has been used to obtain microscopic strain profiles in thin Au/Ni multilayers. Depth profiles of strains in these multilayers, with repeat periodicities varying from 0.82 nm to 9.0 nm, are obtained by an iterative fitting of the calculated diffraction pattern with the experimental one. Interfacial coherency is found to play an important role in understanding the origin of the supermodulus effect in metallic multilayers.

Effects of Surface Preparation on Epitaxial GaN on 6H-SIC Deposited Via Mocvd

A comparison was made of 6H-SiC surfaces etched with H2, C2H4/H2, and HCl/H2, and the resulting crystal quality of epitaxial GaN films deposited on these substrates. To remove the many fine scratches and to smooth the rough surfaces typical of commercial SiC substrates, the Si-face 6H-SiC substrates were etched in H2, C2H4/H2, and HCl/H2 at 1450°C. GaN was subsequently deposited on these etched surfaces after first depositing a low temperature GaN buffer layer via metalorganic chemical vapor deposition (MOCVD). The surface morphologies after etching and after GaN deposition were characterized by atomic force microscopy and Normaski differential interference contrast microscopy, while the crystal quality of the GaN films was assessed by double crystal x-ray rocking curves and x-ray topography. 6H-SiC substrate surfaces were improved in terms of the removal of scratches and the reduction of surface roughness, and both surface morphology and crystal quality of the subsequently deposited GaN films were enhanced. However, the dislocation density was not decreased by the surface etching. The best GaN film was produced by etching the substrate in pure H2 for 40 minutes before growth. Recommendations for the optimum substrate treatment are made.

Oxidation of Aluminum Nitride for Defect Characterization

The thermal oxidation of aluminum nitride was developed as a means to study defects in bulk aluminum nitride crystals. The oxidation kinetics was established for the dry oxidation of highly textured AlN polycrystals produced by sublimation-recombination crystal growth in a tungsten furnace. Despite seeding on polycrystalline tungsten, the grains were predominantly [0001] oriented as verified by electron backscattering diffraction (EBSD). The oxidation rate is dependent on the crystal’s orientation, polarity, stress, and surface condition, thus oxidation decorates grain boundaries, polishing scratches, and inversion domains by producing oxide layers of different thicknesses. The initial oxidation rate of nitrogen polar (0001) AlN is approximately 25% faster than on aluminum polar crystals. Low temperature (800 °C) dry oxidation produced an amorphous oxide layer and generated a high density of defects (vacancies, stacking faults, and dislocations) in the nitride near the oxide/nitride interface, as observed by cross-sectional transmission electron microscopy. In contrast, high temperature oxidation (1000 °C) produced a crystalline oxide layer, and left the nitride free of observable defects.

Training outcomes in colorectal cancer surgery in a district general hospital

OBJECTIVES

The purpose of this study was to quantify the effect of training on outcomes following colorectal cancer resections in a District General Hospital.

PATIENTS AND METHODS

Data on 102 consecutive elective colorectal cancer resections performed at a District General Hospital over a three-year period were prospectively collated. The proportion of cases performed by trainees was recorded and the seniority of the operating surgeon was related to pre-operative morbidity, operative time and postoperative outcome.

RESULTS

Consultants, staff grades and registrars performed 46, 35 and 21 procedures respectively. Of the cases performed by registrars, consultant supervision was provided in seven cases, with staff grades providing supervision in 14 cases. As compared with consultants, registrars were less likely to undertake anterior resection (p = 0.001). However, the mean operating times of trainees (145 +/- 8 mins) and consultants (135 +/- 6 mins) were similar. There were no significant differences between the groups with respect to postoperative mortality or morbidity. There was a trend towards more advanced disease in consultant cases, and consultants had a significantly poorer freedom from death or recurrence at two years as compared with trainees (p = 0.03).

CONCLUSIONS

In our unit, trainees performed 21% of all elective colorectal resections with no detrimental effect on length of hospital stay, overall hospital costs and early and late patient outcomes. Major colorectal procedures can be successfully accomplished in a District General setting by trainees, with the training burden shared between consultants and staff grade surgeons.

Effect of mercury and organomercurials on cellular glucose utilization: a study using resting mercury-resistant yeast cells

AIMS

Mercury compounds are highly toxic to all types of living cells. Isolated yeast strains of Rhodotorula rubra showed high and low resistance pattern towards mercury and organomercurial compounds. To investigate the basis of differential sensitivity of these two types of strains, glucose utilization was measured in the presence of mercury compounds.

METHODS AND RESULTS

Glucose utilization process remained unaffected in resting cells of highly Hg(2+)-resistant strain in the presence of HgCl(2) but not in the presence of phenylmercuric acetate and thimerosal. However, HgCl(2) significantly affected glucose utilization in the case of low-resistant cells. The Hg-retaining ability of the cell wall of highly Hg(2+)-resistant yeast strain was greater than that of the weakly Hg(2+)-resistant strain. The spheroplast-bound Hg(2+) was also significantly less in the highly Hg(2+)-resistant strain than in the weakly Hg(2+)-resistant strain.

CONCLUSIONS

Glucose uptake machinery was not affected in the presence of toxic metal ions in the case of high-resistant strains. But in the case of low Hg(2+)-resistant strain, glucose transport system may be affected either by inactivation of sensor proteins containing -SH group associated with glucose uptake.

SIGNIFICANCE AND IMPACT OF THE STUDY

Cell wall of mercury-resistant yeast cells may play an important role in heavy metal bioremediation process.

Estrogen treatment improves spatial learning in APP + PS1 mice but does not affect beta amyloid accumulation and plaque formation

We investigated the effects of ovariectomy (OVX) and 17 beta-estradiol (0.18 mg per pellet) treatment on spatial learning and memory, hippocampal beta amyloid (A beta) levels, and amyloid plaque counts in double transgenic mice (A/P) carrying mutated amyloid precursor protein (APPswe) and presenilin-1 (PS1-A246E). After OVX at 3 months of age, the mice received estrogen treatment for the last 3 months of their lifetime before they were killed at 6, 9, or 12 months of age. Estrogen treatment in A/P OVX mice increased the number of correct choices in a position discrimination task in the T-maze, and slightly improved their performance in a win-stay task (1/8 arms baited) in the radial arm maze (RAM). However, estrogen treatment did not reverse the A beta-dependent cognitive deficits of A/P mice in the water maze (WM) spatial navigation task. Furthermore, ovariectomy or estrogen treatment in OVX and sham-operated A/P mice had no effect on hippocampal amyloid accumulation. These results show that the estrogen treatment in a transgenic mouse model of Alzheimer's disease (AD) improves performance in the same learning and memory tasks as in the normal C57BL/6J mice. However, the estrogen effects in these mice appeared to be unrelated to A beta-induced cognitive deficits. Our results do not support the idea that estrogen treatment decreases the risk or alleviates the symptoms of Alzheimer's disease by inhibiting the accumulation of A beta or formation of amyloid plaques.

Telomere dysfunction impairs DNA repair and enhances sensitivity to ionizing radiation

Telomeres are specialized nucleoprotein complexes that serve as protective caps of linear eukaryotic chromosomes. Loss of telomere function is associated with rampant genetic instability and loss of cellular viability and renewal potential. The telomere also participates in processes of chromosomal repair, as evidenced by the 'capture' or de novo synthesis of telomere repeats at double-stranded breaks and by the capacity of yeast telomeres to serve as repositories of essential components of the DNA repair machinery, particularly those involved in non-homologous end-joining (NHEJ). Here we used the telomerase-deficient mouse, null for the essential telomerase RNA gene (Terc), to assess the role of telomerase and telomere function on the cellular and organismal response to ionizing radiation. Although the loss of telomerase activity per se had no discernable impact on the response to ionizing radiation, the emergence of telomere dysfunction in late-generation Terc-/- mice imparted a radiosensitivity syndrome associated with accelerated mortality. On the cellular level, the gastrointestinal crypt stem cells and primary thymocytes showed increased rates of apoptosis, and mouse embryonic fibroblasts (MEFs) showed diminished dose-dependent clonogenic survival. The radiosensitivity of telomere dysfunctional cells correlated with delayed DNA break repair kinetics, persistent chromosomal breaks and cytogenetic profiles characterized by complex chromosomal aberrations and massive fragmentation. Our findings establish a intimate relationship between functionally intact telomeres and the genomic, cellular and organismal response to ionizing radiation.

Interplay of p53 and DNA-repair protein XRCC4 in tumorigenesis, genomic stability and development

XRCC4 is a non-homologous end-joining protein employed in DNA double strand break repair and in V(D)J recombination. In mice, XRCC4-deficiency causes a pleiotropic phenotype, which includes embryonic lethality and massive neuronal apoptosis. When DNA damage is not repaired, activation of the cell cycle checkpoint protein p53 can lead to apoptosis. Here we show that p53-deficiency rescues several aspects of the XRCC4-deficient phenotype, including embryonic lethality, neuronal apoptosis, and impaired cellular proliferation. However, there was no significant rescue of impaired V(D)J recombination or lymphocyte development. Although p53-deficiency allowed postnatal survival of XRCC4-deficient mice, they routinely succumbed to pro-B-cell lymphomas which had chromosomal translocations linking amplified c-myc oncogene and IgH locus sequences. Moreover, even XRCC4-deficient embryonic fibroblasts exhibited marked genomic instability including chromosomal translocations. Our findings support a crucial role for the non-homologous end-joining pathway as a caretaker of the mammalian genome, a role required both for normal development and for suppression of tumours.

Distinct functions of eukaryotic translation initiation factors eIF1A and eIF3 in the formation of the 40 S ribosomal preinitiation complex

We have used an in vitro translation initiation assay to investigate the requirements for the efficient transfer of Met-tRNAf (as Met-tRNAf.eIF2.GTP ternary complex) to 40 S ribosomal subunits in the absence of mRNA (or an AUG codon) to form the 40 S preinitiation complex. We observed that the 17-kDa initiation factor eIF1A is necessary and sufficient to mediate nearly quantitative transfer of Met-tRNAf to isolated 40 S ribosomal subunits. However, the addition of 60 S ribosomal subunits to the 40 S preinitiation complex formed under these conditions disrupted the 40 S complex resulting in dissociation of Met-tRNAf from the 40 S subunit. When the eIF1A-dependent preinitiation reaction was carried out with 40 S ribosomal subunits that had been preincubated with eIF3, the 40 S preinitiation complex formed included bound eIF3 (40 S.eIF3. Met-tRNAf.eIF2.GTP). In contrast to the complex lacking eIF3, this complex was not disrupted by the addition of 60 S ribosomal subunits. These results suggest that in vivo, both eIF1A and eIF3 are required to form a stable 40 S preinitiation complex, eIF1A catalyzing the transfer of Met-tRNAf.eIF2.GTP to 40 S subunits, and eIF3 stabilizing the resulting complex and preventing its disruption by 60 S ribosomal subunits.

A critical role for DNA end-joining proteins in both lymphogenesis and neurogenesis

XRCC4 was identified via a complementation cloning method that employed an ionizing radiation (IR)-sensitive hamster cell line. By gene-targeted mutation, we show that XRCC4 deficiency in primary murine cells causes growth defects, premature senescence, IR sensitivity, and inability to support V(D)J recombination. In mice, XRCC4 deficiency causes late embryonic lethality accompanied by defective lymphogenesis and defective neurogenesis manifested by extensive apoptotic death of newly generated postmitotic neuronal cells. We find similar neuronal developmental defects in embryos that lack DNA ligase IV, an XRCC4-associated protein. Our findings demonstrate that differentiating lymphocytes and neurons strictly require the XRCC4 and DNA ligase IV end-joining proteins and point to the general stage of neuronal development in which these proteins are necessary.

A targeted DNA-PKcs-null mutation reveals DNA-PK-independent functions for KU in V(D)J recombination

The DNA-dependent protein kinase (DNA-PK) consists of Ku70, Ku80, and a large catalytic subunit, DNA-PKcs. Targeted inactivation of the Ku70 or Ku80 genes results in elevated ionizing radiation (IR) sensitivity and inability to perform both V(D)J coding-end and signal (RS)-end joining in cells, with severe growth retardation plus immunodeficiency in mice. In contrast, we now demonstrate that DNA-PKcs-null mice generated by gene-targeted mutation, while also severely immunodeficient, exhibit no growth retardation. Furthermore, DNA-PKcs-null cells are blocked for V(D)J coding-end joining, but retain normal RS-end joining. Finally, while DNA-PK-null fibroblasts exhibited increased IR sensitivity, DNA-PKcs-deficient ES cells did not. We conclude that Ku70 and Ku80 may have functions in V(D)J recombination and DNA repair that are independent of DNA-PKcs.

Medical prophylaxis and treatment of cystoid macular edema after cataract surgery. The results of a meta-analysis

OBJECTIVE

The study aimed to determine the effectiveness of prophylactic medical intervention in reducing the incidence of cystoid macular edema (CME) and the effectiveness of medical treatment for chronic CME after cataract surgery.

DESIGN

The study design was a systematic review and meta-analysis of published reports of randomized clinical trials (RCTs).

PARTICIPANTS

Sixteen RCTs involving 2898 eyes examining the effectiveness of medical prophylaxis of CME and 4 RCTs involving 187 eyes testing the effectiveness of medical treatment of chronic CME were used in the study.

INTERVENTIONS

Medical prophylaxis of treatment (cyclo-oxygenase inhibitors or corticosteroids) versus control (placebo or active treatment) was performed.

MAIN OUTCOME MEASURES

Incidence of angiographically diagnosed CME, incidence of clinically significant CME, and vision were measured.

RESULTS

Thirty-six articles reported testing a prophylactic medical intervention for CME after cataract surgery. The incidence of CME varied extensively across studies and was related to the study design used. Summary odds ratios (OR) indicated that prophylactic intervention was effective in reducing the incidence of both angiographic CME (OR = 0.36; 95% confidence interval [CI] = 0.28-0.45) and clinically relevant CME (OR = 0.49; 95% CI = 0.33-0.73). There also was a statistically significant positive effect on improving vision (OR = 1.97; 95% CI = 1.14-3.41). A combination of the results of the four RCTs testing medical therapy for chronic CME indicated a treatment benefit in terms of improving final visual acuity by two or more Snellen lines (OR = 2.67; 95% CI = 1.35-5.30). Assessment of the quality of the 20 RCTs included in the meta-analyses indicated problems in the design, execution, and reporting of a number of trials.

CONCLUSION

A combination of the results from RCTs indicates that medical prophylaxis for aphakic and pseudophakic CME and medical treatment for chronic CME are beneficial. Because most of the RCTs performed to date have problems related to quality, a well-designed RCT is needed to confirm this result, using clinical CME and vision as outcomes.

Molecular cloning and functional expression of a human cDNA encoding translation initiation factor 6

Eukaryotic translation initiation factor 6 (eIF6) binds to the 60S ribosomal subunit and prevents its association with the 40S ribosomal subunit. In this paper, we devised a procedure for purifying eIF6 from rabbit reticulocyte lysates and immunochemically characterized the protein by using antibodies isolated from egg yolks of laying hens immunized with rabbit eIF6. By using these monospecific antibodies, a 1.096-kb human cDNA that encodes an eIF6 of 245 amino acids (calculated Mr 26,558) has been cloned and expressed in Escherichia coli. The purified recombinant human protein exhibits biochemical properties that are similar to eIF6 isolated from mammalian cell extracts. Database searches identified amino acid sequences from Saccharomyces cerevisiae, Drosophila, and the nematode Caenorhabditis elegans with significant identity to the deduced amino acid sequence of human eIF6, suggesting the presence of homologues of human eIF6 in these organisms.

Biochemical characterization of mammalian translation initiation factor 3 (eIF3). Molecular cloning reveals that p110 subunit is the mammalian homologue of Saccharomyces cerevisiae protein Prt1

Eukaryotic translation initiation factor 3 (eIF3), which plays an essential role in initiation of protein synthesis, was purified from rabbit reticulocyte lysates using an assay that specifically measures its ability to stimulate the binding of Met-tRNAf (as a Met-tRNAf.eIF2.GTP ternary complex) to 40 S ribosomal subunits. Purified eIF3 consisted of six major polypeptides of molecular masses 110, 67, 42, 40, 36, and 35 kDa but lacked the 170-kDa polypeptide reported to be a constituent of other eIF3 preparations. Characterization of purified eIF3 lacking the 170-kDa polypeptide showed that the eIF3-mediated 40 S initiation complex formed in the presence of AUG codon efficiently joined 60 S ribosomal subunits in an eIF5-dependent reaction to form a functional 80 S initiation complex. eIF3, which was originally bound to the 40 S initiation complex, was released from the 40 S subunit during the subunit joining reaction. Additionally, chicken antibodies raised against rabbit reticulocyte eIF3 were used to immunochemically characterize eIF3 subunits and to isolate a 3.1-kilobase pair human cDNA that encodes the p110 subunit of mammalian eIF3. The derived amino acid sequence (calculated Mr 95,214) shows that the p110 subunit is the mammalian homologue of Saccharomyces cerevisiae protein Prt1p, a subunit of yeast eIF3.

Function of eukaryotic translation initiation factor 1A (eIF1A) (formerly called eIF-4C) in initiation of protein synthesis

We have used an efficient in vitro translation initiation system to show that the mammalian 17-kDa eukaryotic initiation factor, eIF1A (formerly designated eIF-4C), is essential for transfer of the initiator Met-tRNAf (as Met-tRNAf.eIF2.GTP ternary complex) to 40 S ribosomal subunits in the absence of mRNA to form the 40 S preinitiation complex (40 S.Met-tRNAf.eIF2.GTP). Furthermore, eIF1A acted catalytically in this reaction to mediate highly efficient transfer of the Met-tRNAf.eIF2.GTP ternary complex to 40 S ribosomal subunits. The 40 S complex formed was free of eIF1A indicating that its role in 40 S preinitiation complex formation is not to stabilize the binding of Met-tRNAf to 40 S ribosomes. Additionally, the eIF1A-mediated 40 S initiation complex formed in the presence of AUG codon efficiently joined 60 S ribosomal subunits in an eIF5-dependent reaction to form a functional 80 S initiation complex. In contrast to other reports, we found that eIF1A plays no role either in the subunit joining reaction or in the generation of ribosomal subunits from 80 S ribosomes. Our results indicate that the major function of eIF1A is to mediate the transfer of Met-tRNAf to 40 S ribosomal subunits to form the 40 S preinitiation complex.

Mercury and organomercurial resistance in bacteria isolated from freshwater fish of wetland fisheries around Calcutta

Mercury-resistant bacteria belonging to the genera Bacillus, Escherichia, Klebsiella, Micrococcus, Pseudomonas, Salmonella, Sarcina, Shigella, Staphylococcus and Streptococcus were isolated from gills and guts of fresh water fish collected from wetland fisheries around Calcutta, India, contaminated with mercury compounds. The total number of bacteria, as well as Hg-resistant bacteria, were always higher in guts than gills. Bottom-dwelling fish contained higher number of bacteria, including Hg-resistant bacteria, than surface and middle water dwelling fish. They belonged either to narrow-spectrum or to broad-spectrum Hg-resistant groups and they also possessed other heavy metal and antibiotic resistant properties. In the presence of toxic levels of HgCl(2), phenylmercuric acetate (PMA) and methylmercuric chloride (MMC), the lag in growth of the bacterial strains gradually increased with increasing concentration of Hg-compounds. Narrow-spectrum Hg-resistant bacterial strains volatilized only HgCl(2) from the liquid medium in the range of 64-89%, whereas the broad-spectrum group exhibited a high level of HgCl(2) (80-94%), PMA (72-84%) and MMC (64-80%) volatilizing capacity with inducible mercuric reductase and organomercurial lyase enzyme activities in their cell-free extracts. Cell-free extracts prepared from narrow-spectrum Hg-resistant bacterial strains induced by HgCl(2) exhibited Hg(+2)-dependent NADPH oxidation, indicating the presence of only mercuric reductase enzyme.