Dodecylamine rapidly kills of spores of multiple Firmicute species: properties of the killed spores and the mechanism of the killing.

AIMS: Previous work showed that Bacillus subtilis dormant spore killing and germination by dodecylamine take place by different mechanisms. This new work aimed to optimize killing of B. subtilis and other Firmicutes spores and to determine the mechanism of the killing. METHODS AND RESULTS: Spores of seven Firmicute species were killed rapidly by dodecylamine under optimal conditions and more slowly by decylamine or tetradecylamine. The killed spores were not recovered by additions to recovery media, and some of the killed spores subsequently germinated, all indicating that dodecylamine-killed spores truly are dead. Spores of two species treated with dodecylamine were more sensitive to killing by a subsequent heat treatment, and spore killing of at least one species was faster with chemically decoated spores. The cores of dodecylamine-killed spores were stained by the nucleic acid stain propidium iodide, and dodecylamine-killed wild-type and germination-deficient spores released their stores of phosphate-containing small molecules. CONCLUSIONS: This work indicates that dodecylamine is likely a universal sporicide for Firmicute species, and it kills spores by damaging their inner membrane, with attendant loss of this membrane as a permeability barrier. SIGNIFICANCE AND IMPACT OF THE STUDY: There is a significant need for agents that can effectively kill spores of a number of Firmicute species, especially in wide area decontamination. Dodecylamine appears to be a universal sporicide with a novel mechanism of action, and this or some comparable molecule could be useful in wide area spore decontamination.

Killing of bacterial spores by dodecylamine and its effects on spore inner membrane properties.

AIMS: The objective of this study was to determine the effects of Ca-dipicolinic acid (CaDPA), cortex-lytic enzymes (CLEs), the inner membrane (IM) CaDPA channel and coat on spore killing by dodecylamine. METHODS AND RESULTS: Bacillus subtilis spores, wild-type, CaDPA-less due to the absence of DPA synthase or the IM CaDPA channel, or lacking CLEs, were dodecylamine-treated and spore viability and vital staining were all determined. Dodecylamine killed intact wild-type and CaDPA-less B. subtilis spores similarly, and also killed intact Clostridiodes difficile spores ± CaDPA, with up to 99% killing with 1 mol l-1 dodecylamine in 4 h at 45°C with spores at ~108  ml-1 . Dodecylamine killing of decoated wild type and CLE-less B. subtilis spores was similar, but ~twofold faster than for intact spores, and much faster for decoated CaDPA-less spores, with ≥99% killing in 5 min. Propidium iodide stained intact spores ± CaDPA minimally, decoated CaDPA-replete spores or dodecylamine-killed CLE-less spores peripherally, and cores of decoated CaDPA-less spores and dodecylamine-killed intact spores with CLEs. The IM of some decoated CaDPA-less spores was greatly reorganized. CONCLUSIONS: Dodecylamine spore killing does not require CaDPA channels, CaDPA or CLEs. The lack of CaDPA in decoated spores allowed strong PI staining of the spore core, indicating loss of these spores IM permeability barrier. SIGNIFICANCE AND IMPACT OF THE STUDY: This work gives new information on killing bacterial spores by dodecylamine, and how spore IM's relative impermeability is maintained.

Lack of efficient killing of purified dormant spores of Bacillales and Clostridiales species by glycerol monolaurate in a non-aqueous gel.

Inactivation of Bacillales and Clostridiales spores is of interest, since some cause food spoilage and human diseases. A recent publication (mSphere 3: e00597-1, 2018) reported that glycerol monolaurate (GML) in a non-aqueous gel (GMLg) effectively killed spores of Bacillus subtilis, Bacillus cereus and Clostridioides difficile, and Bacillus anthracis spores to a lesser extent. We now show that (i) the B. subtilis spores prepared as in the prior work were impure; (ii) if spore viability was measured by diluting spores 1/10 in GMLg, serially diluting incubations 10-fold and spotting aliquots on recovery plates, there was no colony formation from the 1/10 to 1/1000 dilutions due to GMLg carryover, although thorough ethanol washes of incubated spores eliminated this problem and (iii) GMLg did not kill highly purified spores of B. subtilis, B. cereus, Bacillus megaterium and C. difficile in 3-20 h in the conditions used in the recent publication. GMLg also gave no killing of crude B. subtilis spores prepared as in the recent publication in 5 h but gave ~1·5 log killing at 24 h. Thus, GMLg does not appear to be an effective sporicide, although the gel likely inhibits spore germination and could kill spores somewhat upon long incubations. SIGNIFICANCE AND IMPACT OF THE STUDY: Given potential deleterious effects of spores of Bacillales and Clostridiales, there is an ongoing interest in new ways of spore killing. A recent paper (mSphere 3: e00597-1, 2018) reported that glycerol monolaurate (GML) in a non-aqueous gel (GMLg) effectively killed spores of many species. We now find that (i) the Bacillus subtilis spores prepared as in the previous report were impure and (ii) GMLg gave no killing of purified spores of Bacillales and Clostridiales species in ≤5 h under the published conditions. Thus, GMLg is not an effective sporicide, though may prevent spore germination or kill germinated spores.

Juara Sihat: assessing the sustained impact of a school-based obesity intervention.

INTRODUCTION: Obesity and physical inactivity among school children are among the most challenging health problems in Malaysia. The present study aimed to evaluate the sustained impact of Juara Sihat programme on physical activity level and anthropometric status at 18-month post-intervention. METHOD: Participants of Juara Sihat (n=55) were followed-up at 18 months after completion of the intervention. Juara Sihat intervention was implemented over 12 weeks and focused on four key components: (i) five one-hour nutrition education classes, (ii) four one-hour physical activity education sessions, (iii) family involvement, and (iv) empowerment of Parents and Teachers Association. Anthropometric variables (body mass index, body fat percentage and waist circumference) were measured and physical activity level was evaluated by using Physical Activity Questionnaire for Children (PAQ-C) at baseline (P0), immediately upon completion of intervention (P1), at three-month post-intervention (P2), and at 18-month postintervention (P3). Analyses of repeated measures analysis of covariance (ANCOVA) with intention-to-treat principle were applied. RESULTS: Sustained effects were found in BMI-for-age z-score which showed a reduction (P0 2.41±0.84 vs P3 2.27±0.81) and physical activity level which showed positive improvements (P0 2.46±0.62 vs P3 2.87±0.76) at 18 months after intervention was completed. Body fat and waist circumference had increased over the same time period. CONCLUSION: Overall, this study successfully demonstrated sustained intervention effects of Juara Sihat intervention on BMI-for-age z-score and physical activity, but not on body fat percentage and waist circumference.

Automated computer-based CT stratification as a predictor of outcome in hypersensitivity pneumonitis.

BACKGROUND: Hypersensitivity pneumonitis (HP) has a variable clinical course. Modelling of quantitative CALIPER-derived CT data can identify distinct disease phenotypes. Mortality prediction using CALIPER analysis was compared to the interstitial lung disease gender, age, physiology (ILD-GAP) outcome model. METHODS: CALIPER CT analysis of parenchymal patterns in 98 consecutive HP patients was compared to visual CT scoring by two radiologists. Functional indices including forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLco) in univariate and multivariate Cox mortality models. Automated stratification of CALIPER scores was evaluated against outcome models. RESULTS: Univariate predictors of mortality included visual and CALIPER CT fibrotic patterns, and all functional indices. Multivariate analyses identified only two independent predictors of mortality: CALIPER reticular pattern (p = 0.001) and DLco (p < 0.0001). Automated stratification distinguished three distinct HP groups (log-rank test p < 0.0001). Substitution of automated stratified groups for FVC and DLco in the ILD-GAP model demonstrated no loss of model strength (C-Index = 0.73 for both models). Model strength improved when automated stratified groups were combined with the ILD-GAP model (C-Index = 0.77). CONCLUSIONS: CALIPER-derived variables are the strongest CT predictors of mortality in HP. Automated CT stratification is equivalent to functional indices in the ILD-GAP model for predicting outcome in HP. KEY POINTS: • Computer CT analysis better predicts mortality than visual CT analysis in HP. • Quantitative CT analysis is equivalent to functional indices for prognostication in HP. • Prognostication using the ILD-GAP model improves when combined with quantitative CT analysis.

Contrast-enhanced spectral mammography in recalls from the Dutch breast cancer screening program: validation of results in a large multireader, multicase study.

OBJECTIVES: Contrast-enhanced spectral mammography (CESM) is a promising problem-solving tool in women referred from a breast cancer screening program. We aimed to study the validity of preliminary results of CESM using a larger panel of radiologists with different levels of CESM experience. METHODS: All women referred from the Dutch breast cancer screening program were eligible for CESM. 199 consecutive cases were viewed by ten radiologists. Four had extensive CESM experience, three had no CESM experience but were experienced breast radiologists, and three were residents. All readers provided a BI-RADS score for the low-energy CESM images first, after which the score could be adjusted when viewing the entire CESM exam. BI-RADS 1-3 were considered benign and BI-RADS 4-5 malignant. With this cutoff, we calculated sensitivity, specificity and area under the ROC curve. RESULTS: CESM increased diagnostic accuracy in all readers. The performance for all readers using CESM was: sensitivity 96.9 % (+3.9 %), specificity 69.7 % (+33.8 %) and area under the ROC curve 0.833 (+0.188). CONCLUSION: CESM is superior to conventional mammography, with excellent problem-solving capabilities in women referred from the breast cancer screening program. Previous results were confirmed even in a larger panel of readers with varying CESM experience. KEY POINTS: • CESM is consistently superior to conventional mammography • CESM increases diagnostic accuracy regardless of a reader's experience • CESM is an excellent problem-solving tool in recalls from screening programs.

Fruit and Vegetable Consumption among Special School Students with Mild Intellectual Disability in Hong Kong.

OBJECTIVE: The aim of this study was to predict the fruit and vegetable consumption intention of students with mild intellectual disability in Hong Kong by the application of Ajzen's Theory of Planned Behaviour. METHODS: 50 students with mild intellectual disability (30 male and 20 female), ranging in age from 15 to 38 years, were participated in this study. By means of face-to-face interviews, demographic data, Food Preference and variables of Theory of Planned Behaviour, such as Attitude, Subjective Norm and Perceived Behavioural Control were measured. RESULTS: 20%, 28% and 10% students with mild intellectual disability were rated to be overweight, obese and severely obese respectively. The rest of 10% were classified to be underweight. Regarding the daily intake of fruit and vegetable, 96% students with mild intellectual disability failed to consume sufficient amount. The variables of Theory of Planned Behaviour explained 47.7% of fruit and vegetable consumption intention with significant factors of Attitude, Subjective Norm and Perceived Behavioural Control. Food Preference was found to be a useful construct and further improve the prediction by about 7% after incorporating into the model. CONCLUSIONS: Results of this study indicated that Theory of Planned Behaviour is a useful model to predict dietary intention of students with mild intellectual disability in Hong Kong. Food Preference was a significant predictor to model the intention of fruit and vegetable consumption among students other than Attitude, Subjective Norm and Perceived Behavioural Control.

Stage T3a renal cell carcinoma: staging accuracy of CT for sinus fat, perinephric fat or renal vein invasion.

OBJECTIVE: To study the accuracy of CT for staging T3a (TNM 2009) renal cell carcinoma (RCC). METHODS: Unenhanced and nephrographic phase CT studies of 117 patients (male:female = 82:35; age range, 21-86 years) with T1-T3a RCC were independently reviewed by 2 readers. The presence of sinus or perinephric fat, or renal vein invasion and tumour characteristics were noted. RESULTS: Median (range) tumour size was 5.5 (0.9-19.0) cm; and 46 (39%), 16 (14%) and 55 (47%) tumours were pT1, pT2 and pT3a RCC, respectively. The sensitivity/specificity for sinus fat, perinephric fat and renal vein invasion were 71/79%, 83/76% and 59/93% (Reader 1) and 88/71%, 68/72% and 69/91% (Reader 2) with κ = 0.41, 0.43 and 0.61, respectively. Sinus fat invasion was seen in 47/55 (85%) cases with T3a RCC vs 16/55 (29%) and 33/55 (60%) for perinephric fat and renal vein invasion. Tumour necrosis, irregularity of tumour edge and direct tumour contact with perirenal fascia or sinus fat increased the odds of local invasion [odds ratio (OR), 2.5-3.7; p < 0.05; κ = 0.42-0.61]. Stage T3a tumours were centrally located (OR, 3.9; p = 0.0009). CONCLUSION: Stage T3a RCC was identified with a sensitivity of 59-88% and specificity of 71-93% (κ = 0.41-0.61). Sinus fat invasion was the most common invasive feature. ADVANCES IN KNOWLEDGE: Centrally situated renal tumours with an irregular tumour edge, inseparable from sinus structures or the perirenal fascia and CT features of tumour necrosis should alert the reader to the possibility of Stage T3a RCC (OR, 2.5-3.9).

Effects of additional cysteine in fish diet on mercury concentration.

Mercury contamination, especially of seafood, continues to attract public concern. Cysteine, NH2CH(CH2SH)COOH, is a naturally occurring hydrophobic amino acid that contains a thiol group. The purpose of our study was to investigate the use of the additive cysteine in fish diets to reduce mercury concentration in fish, and to observe the effectiveness of dietary cysteine in fish livers. Diets containing 1% and 10% cysteine successfully decreased mercury concentrations in fish compared with the 0% cysteine diet. The liver may have formed excessive lipid droplets or was unable to mobilize lipid stores during exposure to mercury; additional cysteine could help to mobilize excessive lipids in it.

Functional assessment in the multimodality imaging of pancreatic neuro-endocrine tumours.

Pancreatic neuroendocrine tumours comprise a heterogeneous group that are rare but could result in serious manifestations. Surgical excision provides the best approach to treatment but many patients may have small lesions that are difficult to detect, or present with wide spread disease by the time of diagnosis. In addition to clinical assessment and biochemical tests, imaging is a major factor in establishing the diagnosis. Cross-sectional imaging such as US, CT and MR, play a major role in the initial assessment. However, they may miss small lesions or metastatic spread. Functional Imaging became possible with the development of somatostatin receptor imaging using 111In-octreotide, which when combined with anatomical imaging could provide enhanced detection. A major improvement has been achieved by combining receptor and PET inaging through the use of 68Ga-DOTA complexes that have been shown to have a much better sensitivity than other imaging modalities and can provide the basis for radionuclide treatment with 90Y or 177Lu labelled with DOTA complexes.

A 2-year open-label study of galantamine therapy in Chinese Alzheimer's disease patients in Hong Kong.

There was no long-term clinical study on galantamine in Alzheimer's disease (AD) in the Asian population. The objectives of this study were to evaluate the efficacy of galantamine on cognitive function, daily functioning, behavioural symptoms and its safety in Chinese AD patients. This was a 2-year open-label clinical trial. The inclusion criteria were patients with probable AD by the NINCDS-ADRDA criteria. A historical control group (n = 19) of AD patients with no galantamine or other cholinesterase inhibitor therapy was employed. In the galantamine group, 33 and 32 subjects had completed a 1-year and 2-year follow up, respectively. Within the galantamine group and at a 6-month follow up, the Alzheimer's Disease Assessment Scale Cognitive Subscale (ADAS-cog score) showed an improvement of 2.9 +/- 1.18 (p = 0.019, paired t-test) but remained the same at 1 and 2 years. The Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory (ADCS-ADL) deteriorated by 4.31 +/- 2.06 (p = 0.044, paired t-test) at 6 months but showed no significant decline at 1 and 2 years vs. baseline. The Neuropsychiatric Inventory (NPI) score also showed a significant deterioration of 5 +/- 1.99 (p = 0.017, paired t-test) at 6 months, 8.06 +/- 1.97 (p < 0.001, paired t-test) at 1 year and 7.31 +/- 1.76 at 2 years. Comparison between the two groups showed a statistically significant improvement in the 1-year ADAS-cog score but decline in the NPI score in the galantamine vs. control groups. Adverse effects were commonly mild. In Chinese mild-moderate AD patients, galantamine showed beneficial effects mainly on the cognitive function.

Patterns of tooth loss in young adult Hong Kong Chinese patients in 1983 and 1998.

OBJECTIVE: To describe and compare patterns of tooth loss in 2 groups of 21- to 25-year-old Hong Kong Chinese patients examined 15 years apart. MATERIALS AND METHODS: The panoramic radiographs of consecutive young adult patients who attended the primary care department of the Dental School of the University of Hong Kong in 1983 and 1998 were reviewed. RESULTS: The proportions of patients with full dentition were 36.0% in 1983 and 45.1% in 1998. However, when third molars were excluded, the proportions were 44.3% and 62.3%, respectively. The prevalence of missing first molars was 10.5% and 3.2% for the 1983 and 1998 groups, respectively, whereas that for missing third molars was 13.5% and 17.9% and that for missing premolars was 1.9% and 2.4%, respectively; all of the differences were statistically significant (p < 0.01). Although the first molars, especially the lower first molars, were at greatest risk of being lost in both groups, the prevalence of missing first molars fell substantially (10.5% in 1983, 3.2% in 1998); in contrast, the prevalence of missing premolars and third molars increased. CONCLUSIONS: The decline in the prevalence of missing first molars may in part reflect the efficacy of toothbrushing, whereas the increase in missing premolars and third molars reflects increases in orthodontic and oral surgical activity in the intervening period.

Decoloration of textile dyes by alginate-immobilized Trametes versicolor.

Alginate-immobilized Trametes versicolor decolorized Amaranth at similar rates in repeated batch culture when the dye was present in either (i) modified Kirk's medium containing 0.22 gl(-1) ammonium tartrate, (ii) the same buffer, thiamine, trace elements and glucose concentrations as in the modified Kirk's medium, or (iii) glucose alone at either 1, 5 or 10 gl(-1). With glucose alone (0.5 gl(-1)), Amaranth, Reactive Black 5, Reactive Blue 19 and Direct Black 22 had first-order decoloration rate constants of 0.56, 0.76, 0.52, and 0.15 h(-1), respectively. Mixtures of these dyes were also completely decolorized. After four successive decolorations, beads were kept in storage solutions for 48 d at 6 degrees C. CaCl2 (1g l(-1)) was the best storage solution as the beads were easier to handle and had the fastest decoloration rates after storage. Decoloration rates were faster with lower viscosity (less than 2000 cps) alginates and with softer beads which had a lower resistance to compression. Fungal colonization of the beads resulted in higher biomass concentrations with a corresponding higher decoloration rate but the beads became larger, had a lower resistance to compression and a higher percentage of bead breakage in a stirred tank reactor. Biomass, recovered from beads in which there was no growth, could be dispersed while the biomass from colonized beads formed a hollow, spherical shell due to growth on and near the bead surface and no growth in the bead interior. If alginate-immobilized T. versicolor is to be used in a stirred tank reactor, a high biomass loading during the immobilization phase and no fungal growth in the beads is recommended to have high decoloration rates and low bead breakage.

Kinetic studies of the ClO + ClO association reaction as a function of temperature and pressure.

The kinetics of the association reaction of ClO radicals: ClO + ClO + M --> Cl2O2+ M (1), have been investigated as a function of temperature T between 206.0-298.0 K and pressure p between 25-760 Torr using flash photolysis with time-resolved UV absorption spectroscopy. ClO radicals were generated following the photolysis of Br2/Cl2O mixtures in nitrogen diluent gas. Charge coupled device (CCD) detection of time resolved absorptions was used to monitor ClO radicals over a broad wavelength window covering the ClO (A 2Pi<-- X 2Pi) vibronic absorption bands. The high pass filtered ClO absorption cross sections were calibrated as a function of temperature between T = 206.0-320 K, and exhibit a negative temperature dependence. The ClO association kinetics were found to be more rapid than those reported in previous studies, with limiting low and high pressure rate coefficients, in nitrogen bath gas, k0 = (2.78 +/- 0.82) x 10(-32) x (T/300)(-3.99 +/- 0.94) molecule(-2) cm6 s(-1) and k(infinity) = (3.37 +/- 1.67) x 10(-12) x (T/300)(-1.49 +/- 1.81) molecule(-1) cm3 s(-1), respectively, (obtained with the broadening factor F(c) fixed at 0.6). Errors are 2sigma. The pressure dependent ClO association rate coefficients (falloff curves) exhibited some discrepancies at low pressures, with higher than expected rate coefficients on the basis of extrapolation from high pressures (p > 100 Torr). Reanalysis of data excluding kinetic data recorded below p = 100 Torr gave k0 = (2.79 +/- 0.85) x 10(-32) x (T/300)(-3.78 +/- 0.98) molecule(-2) cm6 s(-1) and k(infinity) = (3.44 +/- 1.83)x 10(-12) x (T/300)(-1.73 +/- 1.91) molecule(-1) cm3 s(-1). Potential sources of the low pressure discrepancies are discussed. The expression for k(0) in air bath gas is k0 = (2.62 +/- 0.80) x 10(-32) x (T/300)(-3.78 +/- 0.98) molecule(-2) cm6 s(-1). These results support upward revision of the ClO association rate coefficient recommended for use in stratospheric models, and the stratospheric implications of the results reported here are briefly discussed.

The relationship between non-cognitive symptoms and functional impairment in Alzheimer's disease.

OBJECTIVE: Cognitive impairment is an important determinant for functional impairment in Alzheimer's disease. The role of non-cognitive symptom is uncertain. The objective of this study was to investigate the role of non-cognitive symptoms as predictive factors for functional outcome in A.D. METHODS: This was a retrospective study. Subjects were recruited from the Memory Clinic in Queen Mary Hospital over a two years period. Patients with diagnosis of probable A.D. by NINCDS-ADRDA were identified. Demographic data, Folstein Mini-Mental Status Examination (MMSE), Clinical Dementia Rating (CDR), Neuropsychiatric inventory (NPI), Barthel activities of daily living (ADL) as well as Lawton's Instrumental activities of daily living (IADL) were retrieved. RESULTS: 100 patients were identified. Univariate analysis identified statistically significant correlation between hallucination and disinhibition score with Barthel Index (r=-0.43, p <0.001; r=-0.30, p=0.002 respectively); hallucination and aberrant motor act score with Lawton's IADL (r=-0.21, p=0.038; r=-0.21, p=0.038). MMSE was statistical significantly correlated with the above two functional scores. NPI was not statistical significantly correlated with any one of the functional measures. Multivariate regression analyses showed that hallucination score was an independent predictive factors for the Barthel index but not for the Lawton's IADL. MMSE score was identified to be independent predictive factor for all functional measures. CONCLUSIONS: Global cognitive impairment and hallucination was an important independent predictive factor for functional outcomes. Screening hallucination during the course of A.D. would be helpful. Further studies are needed to show the benefit of treatment of hallucination on the improvement of functional outcomes.

Clinicopathological concordance of dementia diagnoses by community versus tertiary care clinicians.

Subjects enrolled in the Autopsy Program at the University of Southern California Alzheimer's Disease Research Center may receive clinical diagnoses from primary care providers in the community or from specialists in neurology. We reviewed the autopsy concordance rates for 463 subjects for diagnoses made by both groups of clinicians. Seventy-seven percent of the sample met neuropathological criteria for Alzheimer's disease (AD). The overall diagnostic accuracy for this sample was 81 percent. Neurologists assessed 200 of the subjects (43 percent). The diagnostic accuracy for any clinical diagnosis among the non-neurologists was 84 percent, and 78 percent (p = 0.07) among neurologists. For AD, non-neurologists had a diagnostic concordance rate of 91 percent and neurologists 87 percent. Where neuropathological AD was missed, non-neurologists had failed to detect any cognitive impairment; neurologists had diagnosed Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Erroneous clinical diagnoses of AD missed dementia with Lewy bodies (DLB) or AD concurrent with Parkinson's disease (PD). Our findings identify specific foci for improving clinical diagnosis of dementia among all physicians managing dementia.

Control of DNA rereplication via Cdc2 phosphorylation sites in the origin recognition complex.

Cdc2 kinase is a master regulator of cell cycle progression in the fission yeast Schizosaccharomyces pombe. Our data indicate that Cdc2 phosphorylates replication factor Orp2, a subunit of the origin recognition complex (ORC). Cdc2 phosphorylation of Orp2 appears to be one of multiple mechanisms by which Cdc2 prevents DNA rereplication in a single cell cycle. Cdc2 phosphorylation of Orp2 is not required for Cdc2 to activate DNA replication initiation. Phosphorylation of Orp2 appears first in S phase and becomes maximal in G(2) and M when Cdc2 kinase activity is required to prevent reinitiation of DNA replication. A mutant lacking Cdc2 phosphorylation sites in Orp2 (orp2-T4A) allowed greater rereplication of DNA than congenic orp2 wild-type strains when the limiting replication initiation factor Cdc18 was deregulated. Thus, Cdc2 phosphorylation of Orp2 may be redundant with regulation of Cdc18 for preventing reinitiation of DNA synthesis. Since Cdc2 phosphorylation sites are present in Orp2 (also known as Orc2) from yeasts to metazoans, we propose that cell cycle-regulated phosphorylation of the ORC provides a safety net to prevent DNA rereplication and resulting genetic instability.

Potency of bupivacaine stereoisomers tested in vitro and in vivo: biochemical, electrophysiological, and neurobehavioral studies.

BACKGROUND: Chiral local anesthetics, such as ropivacaine and levobupivacaine, have the potential advantage over racemic mixtures in showing reduced toxic side effects. However, these S-(levo, or "-")isomers also have reportedly lower potency than their optical antipode, possibly resulting in no advantage in therapeutic index. Potency for local anesthetics inhibiting Na+ channels or action potentials depends on the pattern of membrane potential and so also does the stereopotency ratio. Here the authors have quantitated the stereopotencies of R-, S-, and racemic bupivacaine, comparing several in vitro assays of neuronal Na+ channels with those from in vivo functional nerve block, to establish relative potencies and to understand better the role of different modes of channel inhibition in overall functional anesthesia. METHODS: The binding of bupivacaine to Na+ channels was assessed indirectly by its antagonism of [3H]-batrachotoxin binding to rat brain synaptosomes. Inhibition of Na+ currents by bupivacaine was directly assayed in voltage-clamped GH-3 neuroendocrine cells. Neurobehavioral functions were disrupted by bupivacaine percutaneously injected (0.1 ml; 0.0625-1.0%) at the rat sciatic nerve and semiquantitatively assayed. Concentration-dependent actions of R-, S-, and racemic bupivacaine were compared for their magnitude and duration of action. RESULTS: Competitive batrachotoxin displacement has a stereopotency ratio of R:S = 3:1. Inhibition of Na+ currents with different prepulse potentials shows that S > R potency when the membrane is hyperpolarized, and R > S potency when it is depolarized from normal resting values. Functional deficits assayed in vivo usually demonstrate no consistent enantioselectivity and only a modest stereopotency (R:S = 1.2-1.3) for peak analgesia achieved at the lowest doses. Other functions display no significant stereopotency in either the degree, the duration, or their product (area under the curve) at any dose. CONCLUSION: Although the in vitro actions of bupivacaine showed stereoselectivity ratios of 1.3-3:1 (R:S), in vivo nerve block at clinically used concentrations showed much smaller ratios for peak effect and no significant enantioselectivity for duration. A primary role for the blockade of resting rather than open or inactivated Na+ channels may explain the modest stereoselectivity in vivo, although stereoselective factors controlling local disposition cannot be ruled out. Levo-(S-)bupivacaine is effectively equipotent to R- or racemic bupivacaine in vivo for rat sciatic nerve block.

Treatment of palmar hyperhidrosis using tap water iontophoresis: local experience.

To evaluate the efficacy and safety of tap water iontophoresis in the treatment of severe idiopathic palmar hyperhidrosis, nine Chinese patients with severe palmar hyperhidrosis that had failed to respond to topical aluminium chloride were given 6 weeks' treatment with tap water iontophoresis at the Social Hygiene Service, Department of Health, Hong Kong. The reduction in sweat output was assessed objectively and subjectively. The mean objective reduction in sweat output was 49%, 51%, 26%, and 22% at week 3, 6, 10, and 12, respectively, since the start of treatment with tap water iontophoresis The mean subjective improvements were 43%, 59%, 30%, and 12% at week 3, 6,10, and 12, respectively. The side effects reported were all mild and transient. We conclude that tap water iontophoresis is a safe and useful treatment modality for palmar hyperhidrosis.