Cone-rod dystrophy due to mutations in a novel photoreceptor-specific homeobox gene (CRX) essential for maintenance of the photoreceptor

Genes associated with inherited retinal degeneration have been found to encode proteins required for phototransduction, metabolism, or structural support of photoreceptors. Here we show that mutations in a novel photoreceptor-specific homeodomain transcription factor gene (CRX) cause an autosomal dominant form of cone-rod dystrophy (adCRD) at the CORD2 locus on chromosome 19q13. In affected members of a CORD2-linked family, the highly conserved glutamic acid at the first position of the recognition helix is replaced by alanine (E80A). In another CRD family, a 1 bp deletion (E168 [delta1 bp]) within a novel sequence, the WSP motif, predicts truncation of the C-terminal 132 residues of CRX. Mutations in the CRX gene cause adCRD either by haploinsufficiency or by a dominant negative effect and demonstrate that CRX is essential for the maintenance of mammalian photoreceptors.

Oral pilocarpine for post-irradiation xerostomia in patients with head and neck cancer

BACKGROUND AND METHODS

We evaluated pilocarpine hydrochloride for the treatment of radiation-induced xerostomia, a common complication of irradiation of the head and neck. A prospective, randomized, double-blind, placebo-controlled trial was undertaken to test the safety and efficacy of pilocarpine, particularly in reversing the decrease in the production of saliva and other manifestations of xerostomia. Patients received either placebo or pilocarpine (5 mg or 10 mg orally three times a day) for 12 weeks and were evaluated at base line and every 4 weeks.

RESULTS

We studied 207 patients who had each received > or = 4000 cGy of radiation to the head and neck. In the patients receiving the 5-mg dose of pilocarpine, oral dryness improved in 44 percent, as compared with 25 percent of the patients receiving placebo (P = 0.027). There was overall improvement in 54 percent of the 5-mg group as compared with 25 percent of the placebo group (P = 0.003), and 31 percent of the 5-mg group had improved comfort of the mouth and tongue, as compared with 10 percent of the placebo group (P = 0.002). Speaking ability improved in 33 percent of the 5-mg group as compared with 18 percent of the placebo group (P = 0.037). Saliva production was improved, but it did not correlate with symptomatic relief. There were comparable improvements in the group receiving the 10-mg dose. The primary adverse effect was sweating, in addition to other minor cholinergic effects. Six and 29 percent of the patients in the 5-mg and 10-mg groups, respectively, withdrew from the study because of adverse effects. There were no serious adverse effects related to pilocarpine.

CONCLUSIONS

Pilocarpine improved saliva production and relieved symptoms of xerostomia after irradiation for cancer of the head and neck, with minor side effects that were predominantly limited to sweating.

Initial evaluation of human recombinant interleukin-1 receptor antagonist in the treatment of sepsis syndrome: a randomized, open-label, placebo-controlled multicenter trial

OBJECTIVES

To evaluate the safety, pharmacokinetics, and efficacy of human recombinant interleukin-1 receptor antagonist (IL-1ra) in the treatment of patients with sepsis syndrome.

DESIGN

Prospective, open-label, placebo-controlled, phase II, multicenter clinical trial using three different doses of human recombinant IL-1ra.

SETTING

Twelve academic medical center intensive care units in the United States.

PATIENTS

Ninety-nine patients with sepsis syndrome or septic shock who received standard supportive care and antimicrobial therapy, in addition to infusion with escalating doses of IL-1ra or placebo.

INTERVENTIONS

Patients received an intravenous loading dose of either human recombinant IL-1ra (100 mg) or placebo, followed by a 72-hr intravenous infusion of either one of three doses of IL-1ra (17, 67, or 133 mg/hr) or placebo. All patients were evaluated for 28-day, all-cause mortality.

MEASUREMENTS AND MAIN RESULTS

A dose-dependent, 28-day survival benefit was associated with IL-1ra treatment (p = .015), as indicated by the following mortality rates: 11 (44%) deaths among 25 placebo patients; eight (32%) deaths among 25 patients receiving IL-1ra 17 mg/hr; six (25%) deaths among 24 patients receiving IL-1ra 67 mg/hr; and four (16%) deaths among 25 patients receiving IL-1ra 133 mg/hr. A dose-related survival benefit was observed with infusion of IL-1ra in patients with septic shock at study entry (n = 65; p = .002) and in patients with Gram-negative infection (n = 45; p = .04). Patients with an increased circulating interleukin-6 (IL-6) concentration of > 100 pg/mL at study entry demonstrated a dose-related survival benefit with IL-1ra treatment (p = .009). In patients with an increased IL-6 concentration at study entry, the magnitude of the decrease in IL-6 concentration 24 hrs after the initiation of therapy was correlated with increasing the IL-1ra treatment dose (p = .052). A significant dose-related reduction in the Acute Physiology and Chronic Health Evaluation (APACHE II) score was achieved by the end of infusion (p = .038). A renal elimination mechanism for IL-1ra was suggested by the positive correlation between IL-1ra plasma clearance and estimated creatinine clearance (p = .001; r2 = .51). Human recombinant IL-1ra was well tolerated.

CONCLUSIONS

This initial evaluation suggests that human recombinant IL-1ra is safe and may provide a dose-related survival advantage to patients with sepsis syndrome. A larger, definitive clinical trial is needed to confirm these findings.

Enhancement of allergic inflammation by the interaction between diesel exhaust particles and the immune system

There is growing evidence that fossil fuel combustion products act as adjuvants in the immune system and may lead to enhancement of allergic inflammation. Through this mechanism, particulate air pollutants may be an important contributor to the increased prevalence and morbidity of asthma and allergic rhinitis. In this communication we focus on the role of diesel exhaust particles (DEPs) in skewing the immune response towards IgE production and induction of allergic inflammation. We review experimental studies in animals and humans showing that DEPs enhance IgE production by a variety of mechanisms, including effects on cytokine and chemokine production, as well as activation of macrophages and other mucosal cell types. We discuss metabolic and cellular activation pathways linked to chemicals such as polycyclic aromatic hydrocarbons contained in DEPs and demonstrate how these molecular events may impact cytokine, chemokine, and accessory molecule expression in the immune system.

Calcium- and vitamin D-regulated keratinocyte differentiation

Calcium and 1,25 dihydroxyvitamin D (1,25(OH)(2)D) regulate the differentiation of keratinocytes. We have examined the mechanisms by which such regulation takes place, focusing primarily on the events leading to cornified envelope (CE) formation, in particular the mechanisms by which calcium and 1,25(OH)(2)D regulate the induction of involucrin, a component of the CE, and transglutaminase, the enzyme cross-linking involucrin and other substrates to form the CE. Both extracellular calcium (Ca(o)) and 1,25(OH)(2)D raise intracellular free calcium (Ca(i)) as a necessary step toward stimulating differentiation. Cells lacking the calcium sensing receptor (CaR) or phospholipase C-gamma 1 (PLC-gamma 1) fail to respond to Ca(o) or 1,25(OH)(2)D with respect to differentiation. Residing in the promoter of involucrin is a region responsive to calcium and 1,25(OH)(2)D, the calcium response element (CaRE). The CaRE contains an AP-1 site, mutations of which result in loss of responsiveness to Ca(o) and 1,25(OH)(2)D, indicating a role for protein kinases C (PKC). PKC alpha is the major PKC isozyme involved at least for calcium-induced differentiation. Thus, the regulation of keratinocyte differentiation by calcium and 1,25(OH)(2)D involves a number of signaling pathways including PLC and PKC activation, leading to the induction of proteins required for the differentiation process.

An archaebacterial ATPase, homologous to ATPases in the eukaryotic 26 S proteasome, activates protein breakdown by 20 S proteasomes

In eukaryotes, the 20 S proteasome is the proteolytic core of the 26 S proteasome, which degrades ubiquitinated proteins in an ATP-dependent process. Archaebacteria lack ubiquitin and 26 S proteasomes but do contain 20 S proteasomes. Many archaebacteria, such as Methanococcus jannaschii, also contain a gene (S4) that is highly homologous to the six ATPases in the 19 S (PA700) component of the eukaryotic 26 S proteasome. To test if this putative ATPase may regulate proteasome function, we expressed it in Escherichia coli and purified the 50-kDa product as a 650-kDa complex with ATPase activity. When mixed with the well characterized 20 S proteasomes from Thermoplasma acidophilum and ATP, this complex stimulated degradation of several unfolded proteins 8-25-fold. It also stimulated proteolysis by 20 S proteasomes from another archaebacterium and mammals. This effect required ATP hydrolysis since ADP and the nonhydrolyzable analog, 5'-adenylyl beta, gamma-imidophosphate, were ineffective. CTP and to a lesser extent GTP and UTP were also hydrolyzed and also stimulated proteolysis. We therefore named this complex PAN for proteasome-activating nucleotidase. However, PAN did not promote the degradation of small peptides, which, unlike proteins, should readily diffuse into the proteasome. This ATPase complex appears to have been the evolutionary precursor of the eukaryotic 19 S complex, before the coupling of proteasome function to ubiquitination.

FlaC, a protein of Campylobacter jejuni TGH9011 (ATCC43431) secreted through the flagellar apparatus, binds epithelial cells and influences cell invasion

Type III secretion systems identified in bacterial pathogens of animals and plants transpose effectors and toxins directly into the cytosol of host cells or into the extracellular milieu. Proteins of the type III secretion apparatus are conserved among diverse and distantly related bacteria. Many type III apparatus proteins have homologues in the flagellar export apparatus, supporting the notion that type III secretion systems evolved from the flagellar export apparatus. No type III secretion apparatus genes have been found in the complete genomic sequence of Campylobacter jejuni NCTC11168. In this study, we report the characterization of a protein designated FlaC of C. jejuni TGH9011. FlaC is homologous to the N- and C-terminus of the C. jejuni flagellin proteins, FlaA and FlaB, but lacks the central portion of these proteins. flaC null mutants form a morphologically normal flagellum and are highly motile. In wild-type C. jejuni cultures, FlaC is found predominantly in the extracellular milieu as a secreted protein. Null mutants of the flagellar basal rod gene (flgF) and hook gene (flgE) do not secrete FlaC, suggesting that a functional flagellar export apparatus is required for FlaC secretion. During C. jejuni infection in vitro, secreted FlaC and purified recombinant FlaC bind to HEp-2 cells. Invasion of HEp-2 cells by flaC null mutants was reduced to a level of 14% compared with wild type, suggesting that FlaC plays an important role in cell invasion.

Binge eating, mood, and quality of life in youth with type 2 diabetes: baseline data from the today study

OBJECTIVE

The current study examines the prevalence of binge eating and its association with adiposity and psychosocial functioning in a large, diverse sample of youth with type 2 diabetes.

RESEARCH DESIGN AND METHODS

In the TODAY study, 678 (mean age 14.0 years; 64.9% girls) of the 704 youth randomized to the study completed a self-report measure of eating disorder symptoms and were categorized as nonovereaters, overeaters, subclinical binge eaters, or clinical binge eaters.

RESULTS

Youth with clinical (6%) and subclinical (20%) levels of binge eating had significantly higher levels and rates of extreme obesity, global eating disorder and depressive symptoms, and impaired quality of life.

CONCLUSIONS

These findings highlight the importance of evaluating youth with type 2 diabetes for the presence of binge eating. Future research is needed to determine the cumulative effects of disordered eating, obesity, and psychosocial distress on adherence to lifestyle change recommendations and longitudinal response to treatment.

In vivo nasal challenge with diesel exhaust particles enhances expression of the CC chemokines rantes, MIP-1alpha, and MCP-3 in humans

Diesel exhaust particles (DEP) enhance allergic inflammation by increasing in vivo IgE and cytokine production in the human upper respiratory mucosa. CC chemokines have been shown to play an important role in inflammation. We examined whether DEP could alter the production of CC chemokines by cells residing in the human nasal mucosa. At both 6 and 24 h following intranasal DEP challenge, the levels of nasal RANTES, MIP-1alpha, and MCP-3 were significantly elevated compared to baseline. In contrast, DEP did not enhance levels of Eotaxin at any time, demonstrating that the action of DEP was not simply a global effect on all CC chemokines. Challenge with saline resulted in no significant change in expression of any chemokine at any time. Challenge with DEP also resulted in an increase in total cell counts in nasal lavage fluids. Increases in lymphocyte, monocyte/macrophage, and neutrophil cells were observed but there was no change in eosinophil cell numbers. In contrast, there was a significant enhancement of ECP protein levels in washes performed 6 to 24 h after DEP challenge. Elevated specific nasal chemokine expression following exposure to DEP likely participates in the inflammation, cellular infiltration, and increase in IgE observed in the absence of allergen.

Acute insulin responses to leucine in children with the hyperinsulinism/hyperammonemia syndrome

Mutations of glutamate dehydrogenase cause the hyperinsulinism/hyperammonemia syndrome by desensitizing glutamate dehydrogenase to allosteric inhibition by GTP. Normal allosteric activation of glutamate dehydrogenase by leucine is thus uninhibited, leading us to propose that children with hyperinsulinism/hyperammonemia syndrome will have exaggerated acute insulin responses to leucine in the postabsorptive state. As hyperglycemia increases beta-cell GTP, we also postulated that high glucose concentrations would extinguish abnormal responsiveness to leucine in hyperinsulinism/hyperammonemia syndrome patients. After an overnight fast, seven hyperinsulinism/hyperammonemia syndrome patients (aged 9 months to 29 yr) had acute insulin responses to leucine performed using an iv bolus of L-leucine (15 mg/kg) administered over 1 min and plasma insulin measurements obtained at -10, -5, 0, 1, 3, and 5 min. The acute insulin response to leucine was defined as the mean increase in insulin from baseline at 1 and 3 min after an iv leucine bolus. The hyperinsulinism/hyperammonemia syndrome group had excessively increased insulin responses to leucine (mean +/- SEM, 73 +/- 21 microIU/ml) compared with the control children and adults (n = 17) who had no response to leucine (1.9 +/- 2.7 microU/ml; P < 0.05). Four hyperinsulinism/hyperammonemia syndrome patients then had acute insulin responses to leucine repeated at hyperglycemia (blood glucose, 150-180 mg/dl). High blood glucose suppressed their abnormal baseline acute insulin responses to leucine of 180, 98, 47, and 28 microU/ml to 73, 0, 6, and 19 microU/ml, respectively. This suppression suggests that protein-induced hypoglycemia in hyperinsulinism/hyperammonemia syndrome patients may be prevented by carbohydrate loading before protein consumption.

Identification of Campylobacter jejuni, C. coli, C. lari, C. upsaliensis, arcobacter butzleri, and A. butzleri-like species based on the glyA gene

Currently, the detection and identification of Campylobacter and Arcobacter species remains arduous, largely due to cross-species phenotypic similarities and a relatively narrow spectrum of biochemical reactivity. We have developed a PCR-hybridization strategy, wherein degenerate primers are used to amplify glyA fragments from samples, which are then subjected to species-specific oligodeoxyribonucleotide probe hybridizations, to identify and distinguish between Campylobacter jejuni, C. coli, C. lari, C. upsaliensis, Arcobacter butzleri, and an A. butzleri-like species. Evaluation of this strategy with genomic DNA from different type strains suggests that this approach is both specific and sensitive and thus may be applicable in a diagnostic assay to identify and differentiate these highly related species.

The CT Swirl Sign Is Associated with Hematoma Expansion in Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Hematoma expansion is an independent determinant of poor clinical outcome in intracerebral hemorrhage. Although the "spot sign" predicts hematoma expansion, the identification requires CT angiography, which limits its general accessibility in some hospital settings. Noncontrast CT, without the need for CT angiography, may identify sites of active extravasation, termed the "swirl sign." We aimed to determine the association of the swirl sign with hematoma expansion.

MATERIALS AND METHODS

Patients with spontaneous intracerebral hemorrhage between 2007 and 2014 who underwent an initial and subsequent noncontrast CT at a single center were retrospectively identified. The swirl sign, on noncontrast CT, was defined as iso- or hypodensity within a hyperdense region that extended across 2 contiguous 5-mm axial CT sections.

RESULTS

A total of 212 patients met the inclusion criteria. The swirl sign was identified in 91 patients with excellent interobserver agreement (κ = 0.87). The swirl sign was associated with larger initial hematoma (P < .001) and earlier initial CT (P < .001) and hematoma expansion (P = .028). Multivariable regression modeling demonstrated that if one assumed similar initial hematoma volume, onset-to-first scan, and time between CT scans, the median absolute hematoma growth was 5.77 mL (95% CI, 2.37-9.18 mL; P = .001) and relative growth was 35.6% (95% CI, 18.5%-52.6%; P < .001) higher in patients with the swirl sign compared with those without.

CONCLUSIONS

The NCCT swirl sign was reliably identified and is associated with hematoma expansion. We propose that the swirl sign be included in risk stratification of intracerebral hemorrhage and considered for inclusion in clinical trials.

Clinical standards for the diagnosis, treatment and prevention of TB infection

BACKGROUND: Tuberculosis (TB) preventive therapy (TPT) decreases the risk of developing TB disease and its associated morbidity and mortality. The aim of these clinical standards is to guide the assessment, management of TB infection (TBI) and implementation of TPT.METHODS: A panel of global experts in the field of TB care was identified; 41 participated in a Delphi process. A 5-point Likert scale was used to score the initial standards. After rounds of revision, the document was approved with 100% agreement.RESULTS: Eight clinical standards were defined: Standard 1, all individuals belonging to at-risk groups for TB should undergo testing for TBI; Standard 2, all individual candidates for TPT (including caregivers of children) should undergo a counselling/health education session; Standard 3, testing for TBI: timing and test of choice should be optimised; Standard 4, TB disease should be excluded prior to initiation of TPT; Standard 5, all candidates for TPT should undergo a set of baseline examinations; Standard 6, all individuals initiating TPT should receive one of the recommended regimens; Standard 7, all individuals who have started TPT should be monitored; Standard 8, a TBI screening and testing register should be kept to inform the cascade of care.CONCLUSION: This is the first consensus-based set of Clinical Standards for TBI. This document guides clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage TBI.

Anti-leukotriene agents compared to inhaled corticosteroids in the management of recurrent and/or chronic asthma in adults and children

BACKGROUND

Anti-leukotrienes agents are currently being studied as alternative first line agents to inhaled corticosteroids in mild to moderate chronic asthma.

OBJECTIVES

To compare the safety and efficacy of anti-leukotriene agents with inhaled glucocorticoids (ICS) and to determine the dose-equivalence of anti-leukotrienes to daily dose of ICS.

SEARCH STRATEGY

We searched MEDLINE (1966 to Aug 2003), EMBASE (1980 to Aug 2003), CINAHL (1982 to Aug 2003), the Cochrane Airways Group trials register, and the Cochrane Central Register of Controlled Trials (August 2003), abstract books, and reference lists of review articles and trials. We contacted colleagues and international headquarters of anti-leukotrienes producers.

SELECTION CRITERIA

Randomised controlled trials that compared anti-leukotrienes with inhaled corticosteroids during a minimal 30-day intervention period in asthmatic patients aged 2 years and older.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the methodological quality or trials and extracted trial data. The primary outcome was the rate of exacerbations requiring systemic corticosteroids. Secondary outcomes included lung function, indices of chronic asthma control, adverse effects and withdrawal rates.

MAIN RESULTS

27 trials (including 1 trial testing two protocols) met the inclusion criteria; 13 were of high methodological quality; 20 are published in full-text. All trials pertained to patients with mild to moderate persistent asthma. Only 3 trials focused on children and adolescents. Trial duration varied from 4 to 37 weeks. In most trials, daily dose of ICS was 400 mcg of beclomethasone or equivalent. Patients treated with anti-leukotrienes were 65% more likely to suffer an exacerbation requiring systemic steroids [Relative Risk 1.65; 95% Confidence Interval (CI) 1.36 to 2.00]. Twenty six (95% CI: 17 to 47) patients must be treated with anti-leukotrienes instead of inhaled corticosteroids to cause one extra exacerbation. Significant differences favouring ICS were noted in secondary outcomes where()the improvement in FEV(1) reached 130 mL [13 trials; 95% CI: 50, 140 mL ]. Other significant benefits of ICS were seen for symptoms, nocturnal awakenings, rescue medication use, symptom-free days, and quality of life. Anti-leukotriene therapy was associated with 160% increased risk of withdrawals due to poor asthma control. Twenty nine (95% CI 20 to 48) patients must be treated with anti-leukotrienes instead of inhaled corticosteroids to cause one extra withdrawal due to poor control. Risk of side effects was not different between groups.

REVIEWERS' CONCLUSIONS

Inhaled steroids at a dose of 400 mcg/day of beclomethasone or equivalent are more effective than anti-leukotriene agents given in the usual licensed doses. The exact dose-equivalence of anti-leukotriene agents in mcg of ICS remains to be determined. Inhaled glucocorticoids should remain the first line monotherapy for persistent asthma.

Chromosome 13 dementias

The importance of cerebral amyloid deposition in the mechanism of neurodegeneration is still debatable. Classic arguments are usually centered on amyloid beta(Abeta) and its role in the neuronal loss characteristic of Alzheimer's disease, the most common form of human cerebral amyloidosis. Two non-Abeta cerebral amyloidoses, familial British and Danish dementias (FBD and FDD), share many aspects of Alzheimer's disease, including the presence of neurofibrillary tangles, parenchymal preamyloid and amyloid deposits, cerebral amyloid angiopathy and a variety of amyloid-associated proteins and inflammatory components. Both early-onset conditions are linked to specific mutations at or near the stop codon of the chromosome 13 gene BRI2 that cause generation of longer-than-normal protein products. Furin-like processing of these longer precursors releases two de novo-created peptides, ABri and ADan, which deposit as amyloid fibrils in FBD and FDD, respectively. Due to the similar pathology generated by completely unrelated amyloid subunits, FBD and FDD, collectively referred to as chromosome 13 dementias, constitute alternative models for studying the role of amyloid deposition in the mechanism of neuronal cell death.

Protein tyrosine phosphorylation in Mycobacterium tuberculosis

Crude cell extracts from three strains of Mycobacterium tuberculosis were analyzed for the presence of proteins possessing phosphorylated tyrosine residues. A protein migrating at approximately 55 kDa was detected using an antiphosphotyrosine monoclonal antibody. In addition, less predominant bands were observed between 50 kDa and 60 kDa. That M. tuberculosis contains specific tyrosine phosphorylated proteins implies that M. tuberculosis has tyrosine kinase activity. Examination of other, non-pathogenic mycobacterium species yielded no major antiphosphotyrosine reactive proteins. This suggests that the antiphosphotyrosine reactive protein is specific to M. tuberculosis strains. These results provide evidence that M. tuberculosis contains an antiphosphotyrosine reactive protein.

Pain characteristics and demographics of patients attending a university-affiliated pain clinic in Toronto, Ontario

BACKGROUND

Pain clinics tend to see more complex chronic pain patients than primary care settings, but the types of patients seen may differ among practices.

OBJECTIVE

The aim of the present observational study was to describe the pain and demographic characteristics of patients attending a university-affiliated tertiary care pain clinic in Toronto, Ontario.

METHODS

Data were collected on 1242 consecutive new patients seen over a three-year period at the Comprehensive Pain Program in central Toronto.

RESULTS

Musculoskeletal problems affecting large joints and the spine were the predominant cause of pain (more prevalent in women), followed by neuropathic disorders (more prevalent in men) in patients with recognizable physical pathology. The most affected age group was in the 35- to 49-year age range, with a mean pain duration of 7.8 years before the consultation. While 77% of the Comprehensive Pain Program patients had relevant and detectable physical pathology for pain complaints, three-quarters of the overall study population also had significant associated psychological or psychiatric comorbidity. Women, in general, attended the pain clinic in greater numbers and had less apparent physical pathology than men. Finally, less than one in five patients was employed at the time of referral.

CONCLUSIONS

The relevance of the data in relation to other pain clinics is discussed, as well as waiting lists and other barriers faced by chronic pain patients, pain practitioners and pain facilities in Ontario and Canada.

Quinolizidine alkaloids obtained byPedicularis semibarbata (Scrophulariaceae) fromLupinus fulcratus (Leguminosae) fail to influence the specialist herbivoreEuphydryas editha (Lepidoptera)

Pedicularis semibarbata is apparently an obligate hemiparasite of coniferous trees. It is also a facultative parasite ofLupinus fulcratus from which we find that it obtains quinolizidine alkaloids, principally α-isolupanine. As a result, a single population ofP. semibarbata contains both alkaloidrich and alkaloid-free plants. The butterflyEuphydryas editha naturally oviposits on both plant types. This butterfly population, which is the principal herbivore attackingP. semibarbata at this site, is known to contain two morphs. Individuals of a specialist morph discriminate when ovipositing among individualP. semibarbata plants and produce offspring that survive better on accepted than on rejected plants. Those of a generalist morph accept allP. semibarbata plants and produce offspring that survive equally well on plants accepted or rejected by the discriminating morph. Because of the existence of this complex variation among the butterflies, the presence of naturally laid eggs on alkaloid-containing plants still leaves the possibility that the alkaloids may defend the plants against the specialist morph. In experiments on both oviposition preference and larval performance in early instars, we failed to detect any correlation between alkaloid content of a plant and either its acceptability to or suitability for the discriminating morph of the insect. Alkaloid presence in the host-plant population, achieved through root parasitism, is currently neither subject to strong insect-mediated selection nor a major cause of selection on the insects.

Fine mapping of the three rRNA operons on the updated genomic map of Campylobacter jejuni TGH9011 (ATCC 43431)

The three rRNA gene loci of Campylobacter jejuni TGH9011 (ATCC 43431) were cloned. All three rRNA operons were shown to possess a contiguous 16S-23S structure and contain intercistronic tRNA(Ala) and tRNA(Ile). The three RNA operons and additional 14 genetic markers were mapped in the updated genomic map of C. jejuni TGH9011, which now has a total of 24 genetic markers.

Polymorphisms of human paraoxonase 1 gene (PON1) and susceptibility to diabetic nephropathy in type I diabetes mellitus

AIMS/HYPOTHESIS

Oxidative stress is a putative mechanism in the development of diabetic nephropathy. Paraoxonase gene 1 is an HDL-bound enzyme that protects tissues against oxidative damage. Three common polymorphisms of paraoxonase gene 1, T-107C in the promoter, Leu54Met and Gln192Arg, that modify paraoxonase activity have been associated with cardiovascular disease. This study aimed to find whether these polymorphisms also contribute to the development of diabetic nephropathy.

METHODS

The association between diabetic nephropathy and these three polymorphisms was examined in a case-control study. For this purpose, genomic DNA was collected from 188 patients with Type I (insulin-dependent) diabetes mellitus and diabetic nephropathy and from 179 unrelated patients with Type I diabetes but without diabetic nephropathy despite the duration of diabetes of 15 or more years.

RESULTS

The genotype and allele frequencies for each of the three polymorphisms (T-107C, Leu54Met and Gln192Arg) were similar in cases and control subjects.

CONCLUSION/INTERPRETATION

The three polymorphisms in paraoxonase gene 1 that have been associated with serum levels of paraoxonase are not associated with diabetic nephropathy. We show that this genetically determined component of the antioxidant capacity of HDL does not play a critical part in the development of diabetic nephropathy.

Carbon regulation of ribosomal genes in Neurospora crassa occurs by a mechanism which does not require Cre-1, the homologue of the Aspergillus carbon catabolite repressor, CreA

Transcription of the ribosomal protein and 40S rRNA genes is coordinately regulated during steady state growth and carbon shifts in Neurospora crassa. Recognition sequences for the Aspergillus nidulans carbon catabolite repressor, CreA, overlap transcriptional elements of a 40S rRNA gene and the crp-2 ribosomal protein gene. They also occur in similar locations in the promoters of several other ribosomal protein genes. Substitutions encompassing the -74 and -167 CreA consensus sequences in the crp-2 promoter result in a decrease in transcription. A cDNA encoding the N. crassa homologue of CreA was cloned and designated Cre-1. The Cre-1 protein is 45% identical to CreA from A. nidulans. Cre-1 protein produced in Escherichia coli binds to the CreA sites in the promoters of the 40S rRNA and crp-2 genes. An amino acid change from histidine (92) to threonine changed the Cre-1 binding specificity from (5'G/CC/TGGG/AG3') to (5'G/CC/TGGCG3'). Base substitutions in the Cre-1 binding sites of the crp-2 promoter disrupted binding of wildtype Cre-1 in vitro but had no effect on transcription during steady state growth or carbon shifts, indicating that regulation of ribosomal genes by carbon source is not mediated by Cre-1, but via different proteins binding the Cre-1 sites and the Dde boxes.

Work-related burns: a 6-year retrospective study

During the 6 years from July 1984 to May 1990, 193 patients (30.2 per cent of all patients) were admitted to our regional adult burn centre, for treatment of work-related burn injuries. The median age of patients was 32.5 years (range 18-64 per cent), and 94 per cent were males. Fifty-nine per cent of the patients came from metropolitan Toronto, and 40 per cent from rural Ontario. Most of the patients (97.3 per cent) were referred to the burn centre within 24 h of their injury. The most common aetiology was electrical injury (29.5 per cent), followed by flame (24.4 per cent), contact (10.4 per cent), flash (9.8 per cent), tar and asphalt (9.3 per cent), scald (7.8 per cent), chemical (5.1 per cent), steam (4.7 per cent) and grease (1 per cent). Within the electrical burn group, about one-half were flash burns, one-quarter were clothing fire injuries, and one-quarter were contact injuries. These occupational burns tended to be extensive injuries. The median body surface area (BSA) was 16.5 per cent, with a median full thickness (FT) component of 5.0 per cent. The average length of stay was 20.0 days. Inhalation injury requiring intubation occurred in 14.8 per cent of patients. Sepsis--confirmed by positive blood cultures--developed in 14 per cent of the patients, at an average time of 8.8 days postburn. Staphylococcus aureus was the commonest organism isolated from blood cultures. Pneumonia occurred in 6.3 per cent of patients. A total of 207 surgical procedures was performed on 113 of the 193 patients.(ABSTRACT TRUNCATED AT 250 WORDS)