Radiation-Associated Lymphopenia in Advanced Prostate Cancer Treated with Contemporary Radiation Techniques

PURPOSE/OBJECTIVE(S)

Lymphocytes play a critical role in the immune system as primary effector cells for cancer control, often depleted by external beam radiation therapy (EBRT). Radiation-associated lymphopenia (RAL) has been shown to be a poor prognostic factor in the management of multiple solid tumors. We hypothesize RAL is similarly observed in advanced prostate cancer (PC) RT with contemporary techniques.

MATERIALS/METHODS

We identified patients with advanced PC (high-risk or clinical/pathologic node-positive) receiving EBRT including lymph node/prostatic lesion boost on a prospective collection protocol for whom 1 baseline and ≥2 subsequent complete blood count (CBC) with differential samples were available, collected at RT end, 3-, 6-, and 12-months post-RT. Clinicopathological characteristics were retrieved from chart review. Common Terminology Criteria for Adverse Events (CTCAE)v5 was used to grade absolute lymphocyte count (ALC); RAL was defined as CTCAEv5 grade ≥2. As these patients received pelvic nodal irradiation, they were pooled with low/intermediate-risk PC cohort treated with high dose-rate (HDR) brachytherapy or prostate alone EBRT with similar CBC timepoints for univariable analysis to understand RT field size effect on RAL.

RESULTS

Between 2019 and 2022, among 17 patients in the low/intermediate-risk PC cohort, 6 patients had grade ≥2 lymphopenia. Among 25 patients in the advanced PC cohort, all received androgen deprivation therapy (ADT), 6 received lymph node boost, and 5 received prostatic lesion boost. At RT end, leukopenia was prominently observed (median nadir count 75.1% of baseline), with ALC as major driver (median nadir count 27.3% of baseline). Grade ≥2 lymphopenia was observed in 76% of patients (n = 19) Of 19 advanced PC patients who reached 6 months post-RT follow-up, median ALC was 53.0% of baseline, and Grade ≥2 lymphopenia remained in 37% (n = 7) of patients. Of 8 advanced PC patients who reached 12 months post-RT follow-up, median ALC was 55.6% of baseline. When evaluating whether RT dose or field size contributed to lower nadir ALC counts, combining the low/intermediate-risk and advanced PC cohorts (n = 42), univariable analysis demonstrated Gleason grade group (p = 0.009), RT field size (p = 0.020), ADT use (p = 0.020), baseline ALC (p = 0.037), and baseline hemoglobin (p = 0.009) were independent predictors of Grade ≥2 lymphopenia. Age, prostatic lesion/lymph node boost, and equivalent dose in 2 Gy/fraction (EQD2) were nonsignificant.

CONCLUSION

Grade ≥2 RAL was observed in patients with advanced PC at end of RT, irrespective of age, RT boost, or EQD2. Lymphocyte recovery from baseline can be prolonged even at 12 months post-RT. Ongoing analyses include expanding data with additional serial CBC, increasing cohort size, and integrating effect of additional systemic therapies. RAL has downstream implications for future chemotherapy/radiopharmaceuticals.

Global market trends of flavour capsule and menthol cigarettes in 78 countries, 2010-2020

Background

Flavoured tobacco products, including innovative flavour capsule cigarettes (FCCs) and menthol cigarettes, can increase appeal and encourage smoking initiation and use. Global epidemiological data on these products are scarce.

Methods

This study examined market trends of FCCs and menthol (non-capsule) cigarettes across 78 countries from 2010 to 2020 and assessed ecological-level factors associated with market shares of these products. Market share and retail volume data came from Euromonitor Passport and country-specific sociodemographic data come from the WHO and World Bank. Adjusted linear fixed effects panel regression analyses were used to evaluate the relationship between predictors variables and market outcomes.

Results

Global total retail volume of FCCs increased over time (0.2% in 2010 to 4.5% in 2020) and market share was associated with year and unemployment rate and inversely associated with % urban population and smoking prevalence (p < 0.001). In contrast, menthol retail volume decreased over time (5.0% to 3.8%) and market share was associated with % urban population (p = 0.001) and inversely associated with year (p = 0.004) and unemployment rate (p = 0.017). The greatest market increase of FCCs was observed in the Americas region and among upper-middle income countries. In Europe, there was a decrease of 0.64 percentage points from 2019 to 2020.

Conclusions

Overall, FCCs experienced substantial global growth in the recent decade, with the exception of Europe whose slight decrease may be attributable to the European Union ban on flavours in cigarettes. Findings indicate that there is a need for increased efforts to address flavours and innovative features used in tobacco products, which are known to appeal to youth.

Key messages

• This study contributes to global monitoring of tobacco products.

• Findings can be used by advocates and policy makers to support countries in adopting measures to ban flavoured tobacco products.

Multifunctional colorimetric cellulose acetate membrane incorporated with Perilla frutescens (L.) Britt. anthocyanins and chamomile essential oil

A colorimetric cellulose acetate (CA) membrane incorporated with Perilla frutescens (L.) Britt. anthocyanins (PFA) and chamomile essential oil (CO) is developed via electrospinning technique for food freshness monitoring and shelf-life extending. The moieties of PFA and CO are well-dispersed in fiber matrix by hydrogen bonds and their incorporation increases the fiber size but with no obvious influence on the fiber morphology at incorporation levels. The presence of CO enhances membrane hydrophobicity. The target membrane of CA-PFA6-CO15 (PFA6%, CO15%) has a wide color change range of pH 2-12 which is high sensitive and reversible towards external pH-stimuli. The membrane has good antibacterial activity against E. coli and S. aureus besides antioxidant activity. The release of bioactive moieties is predominantly controlled by Fickian diffusion. The target membrane can simultaneously monitor pork freshness in real-time and double the shelf-life at 25 °C, indicating its potential application in active and intelligent food packaging.

Corticosteroid therapy for patients with severe novel Coronavirus disease 2019

OBJECTIVE

To investigate the effect of corticosteroid on hospital mortality, hospital length of stay, and time of viral clearance in patients with severe and critical COVID-19.

PATIENTS AND METHODS

Patients with severe and critical COVID-19 who had been discharged or expired were enrolled in this study. Patients were divided into corticosteroid group and non-corticosteroid group according to the systemic corticosteroid use or not. Clinical data were collected, and hospital mortality, hospital length of stay, time of viral clearance, time of mechanical ventilation, and duration from illness onset to symptom resolution were compared between the two groups.

RESULTS

A total of 72 inpatients who were diagnosed with severe and critical COVID-19 were enrolled, in which 47 patients were divided into corticosteroid group and 25 were involved as the non-corticosteroid group. Baseline characteristics were generally similar between the two groups. Four (5.6%) patients died during hospitalization, and 68 (94.4%) were discharged. Among survivors, the mean duration time from admission to discharge was 19.5d (SD 7.05 d). The mean time of viral clearance among survivors was 17.5d (SD 7.67 d), with a maximum of 37 d, and a minimum of 5 d. Hospital mortality (4.3% vs. 8.0%), length of hospital stay (18.7d vs. 21.0d), and time of viral clearance (16.1d vs. 19.4d) had no significant difference between two groups (p>0.05). The duration of symptoms suffering was shorter in the corticosteroid group than non-corticosteroid group, with statistically significant difference (p<0.05).

CONCLUSIONS

Corticosteroid therapy in patients with severe COVID-19 cannot reduce the hospital mortality, and is not associated with delayed viral clearance, but it could relieve the inflammatory storm and improve clinical symptoms in brief. Patients with severe COVID-19 could benefit from low-dose corticosteroid treatment.

An emergency strategy for intensive care unit during COVID-19 outbreak in Chongqing, China

OBJECTIVE

Since December 2019, a novel coronavirus disease 2019 (COVID-19) broke out in Wuhan, China, which has rapidly spread from China to at least 200 countries abroad. COVID-19 was issued a global outbreak and pandemic by the World Health Organization with more than 3 million confirmed cases by May 31, 2020. So far more than ten thousand severe and critically ill patients and hospital-related infection with COVID-19 have been reported with more than four thousand deaths in China. There is a great challenge for intensive care units (ICUs) in hospitals.

PATIENTS AND METHODS

The comment mainly focused on admission and discharge criteria, therapy protocol, prevention and control strategies for ICU during COVID-19 outbreak. The emergency strategy for ICU will be helpful for prevention and control of COVID-19 and treatment of critically ill patients with COVID-19.

CONCLUSIONS

Progress in the management of ICU is crucial for a decrease in the mortality of critically ill patients with COVID-19 with the clinical evidence and experience updated.

[Differential protein expressions in papillary thyroid carcinoma patients with or without Hashimoto's thyroiditis]

Objective: To explore the differential protein expressions in papillary thyroid carcinoma (PTC) with or without Hashimoto's thyroiditis (HT). Methods: Tissue microarray was prepared and the protein expression levels of v-Raf murine sarcoma viral oncogene homolog B1 (BRAF), vascular endothelial growth factor (VEGF), cyclinD1, mesothelial cell (MC) , CD56 and Galectin3 in the PTC tissues with or without HT were detected by immunohistochemical staining. Results: The positive expression rates of BRAF protein in the PTC tissues with or without HT groups were 55.4% (36/65) and 63.6% (42/66), respectively, without significant difference (P=0.336). The positive expression rates of VEGF protein in the PTC tissues with or without HT groups were 25.7% (19/74) and 25.8%(17/66), respectively, without significant difference (P=0.991). The positive expression rates of cyclin D1 protein in the PTC tissues with or without HT groups were 93.4% (71/76) and 97.6% (80/82), without significant difference (P=0.206). The positive expression rates of MC protein in the PTC tissues with or without HT groups were 86.1% (62/72) and 83.5%(71/85), without significant difference (P=0.654). The positive expression rates of Galectin3 protein in the PTC tissues with or without HT groups were 98.7% (76/77) and 97.5% (78/80), without significant difference (P=0.583). The positive expression rates of CD56 in the PTC tissues and adjacent thyroid follicular epithelial cells were 27.4% (32/117) and 65.0% (76/117), respectively, and the difference was statistically significant (P=0.001). The positive expression rates of CD56 in PTC tissues with or without HT were 35.5% (24/68) and 16.5% (13/79), respectively, and the difference was statistically significant (P=0.009). Conclusions: There are no significant differences in the expressions of BRAF, VEGF, CyclinD1, MC and Galectin3 between the PTC tissues with or without HT. However, the significantly differential expression of CD56 between the two group suggests that CD56 may be related to the pathogenesis of PTC with HT. CD56 may be used as a potential molecular marker in PTC diagnosis.

Decreasing the pH of milk replacer containing soy flour affects nutrient digestibility, digesta pH, and gastrointestinal development of preweaned calves

We evaluated the effect of feeding soy flour-containing milk replacer (MR) with a lower than normal pH on growth, nutrient digestibility, digesta pH, and gastrointestinal development of preweaned calves. The study consisted of 48 neonatal calves, allocated to 8 treatments in a 2-factor 4×2 randomized design. The calves received 2 types of MR containing soy flour. The proportion of soy crude protein (CP) to total CP (SP/CP) in MR was 50% (MR50 treatment) or 80% (MR80 treatment), respectively. The pH of the reconstituted MR was decreased by 1 N HCl from to 6.2 to 5.5, 5.0, or 4.5. We measured body weight and dry matter intake and calculated feed conversion rate in the MR50 treatment. We monitored urinary and fecal pH consecutively for 5h when calves were 25d old. We also conducted a digestion trial to determine nutrient digestibility from 49 to 55d of age. At 63d old, calves were slaughtered, and gastrointestinal pH, mass index, and morphology were evaluated. Reducing the pH of MR containing soy flour improved average daily gain and feed conversion rate, increased Ca digestibility, and reduced urinary, fecal, and digesta pH in the rumen, reticulum, and omasum. Although treatments had no effect on gastrointestinal mass index, the pH 5.0 treatment led to favorable ruminal epithelium growth, and the pH 5.5 treatment led to better intestinal epithelium growth. Increasing SP/CP from 50 to 80% decreased P digestibility and fecal and digesta pH in rumen, reticulum, and omasum. Moreover, the MR80 treatment reduced the mass index of the abomasums and jejunum. In conclusion, decreasing the pH of MR containing soy flour to a pH of 5.0 to 5.5 improved the digestive tract of preweaned calves. A pH reduction to 4.5 had adverse effects on intestinal epithelium growth.

The surface electronic structure of silicon terminated (100) diamond

A combination of synchrotron-based x-ray spectroscopy and contact potential difference measurements have been used to examine the electronic structure of the (3 × 1) silicon terminated (100) diamond surface under ultra high vacuum conditions. An occupied surface state which sits 1.75 eV below the valence band maximum has been identified, and indications of mid-gap unoccupied surface states have been found. Additionally, the pristine silicon terminated surface is shown to possess a negative electron affinity of -0.86 ± 0.1 eV.

Measuring surface and bulk relaxation in glassy polymers

We present a comprehensive study of gold nanoparticle embedding into polystyrene (PS) surfaces at temperatures ranging from T ( g ) + 8 K to T ( g ) - 83 K and times as long as 10(5) minutes. This range in times and temperatures allows the first concurrent observation of and differentiation between surface and bulk behavior in the 20 nm region nearest the free surface of the polymer film. Of particular importance is the temperature region near the bulk glass transition temperature where both surface and bulk processes can be measured. The results indicate that for the case of PS, enhanced surface mobility only exists at temperatures near or below the bulk T ( g ) value. The surface relaxation times are only weakly temperature dependent and near T ( g ), the enhanced mobility extends less than 10nm into the bulk of the film. The results suggest that both the concept of a "surface glass transition" and the use of glass transition temperatures to measure local mobility near interfaces may not universally apply to all polymers. The results can also be used to make a quantitative connection to molecular dynamics simulations of polymer films and surfaces.

TNF-α acutely upregulates amylin expression in murine pancreatic beta cells

AIMS/HYPOTHESIS

Amylin, a secretory protein mainly produced by pancreatic beta cells, is elevated in the circulation of patients with diseases related to acute and chronic inflammation, including acute pancreatitis, pancreas graft rejection, obesity and insulin resistance. TNF-α is involved in these disorders. We investigated the effect of TNF-α on amylin levels and the underlying mechanisms, using murine pancreatic beta cell line MIN6 and pancreatic islets.

METHODS

Amylin, proinsulin and prohormone convertase 1/3, 2 (Pc1/3, Pc2 [also known as Pcsk1/3 and Pcsk2, respectively]) mRNA levels, and amylin promoter and nuclear factor κB (NF-κB) activation were examined by real-time PCR and luciferase reporter assay, respectively. Amylin protein level and mitogen-activated protein kinase phosphorylation were detected by western blot. Activator protein 1 (AP1) activation was examined by electrophoretic mobility shift assay (EMSA).

RESULTS

TNF-α acutely induced amylin expression at the transcriptional level and increased proamylin and the intermediate form of amylin in MIN6 cells and islets. However, it had no effect on proinsulin, Pc1/3 and Pc2 expression. Studies with (1) MIN6 cells treated with inhibitors of MEK1/2, c-Jun-N-terminal kinase (JNK) or protein kinase Cζ (PKC(ζ)), (2) MIN6 cells expressing a c-Jun-dominant negative construct and (3) islets from Fos knockout mice demonstrated that TNF-α induced amylin expression through the PKC(ζ)-extracellular signal-regulated kinase (ERK)/JNK pathways. EMSA showed that (PKC(ζ)), JNK and ERK1/2 were involved in TNF-α-induced AP1 activation, suggesting that TNF-α induces murine amylin expression through the (PKC(ζ)) - ERK1/2 - AP and PKC(ζ) - JNK - AP1 pathways. Further studies showed that TNF-α also induced murine amylin expression through the phosphatidylinositol 3 kinase-NF-κB signalling pathway and enhanced human amylin promoter activation through NF-κB and AP1.

CONCLUSIONS/INTERPRETATION

TNF-α acutely induces amylin gene expression in beta cells through multiple signalling pathways, possibly contributing to amylin elevation in acute inflammation-related pancreatic disorders.

Experimental observation of the crystallization of a paired holon state

An excitation at 201 meV is observed in the doped-hole ladder cuprate Sr14Cu24O41, using ultraviolet resonance Raman scattering with incident light at 3.7 eV polarized along the rungs. The excitation is of charge nature, with a temperature independent excitation energy, and can be understood via an intraladder pair-breaking process. The intensity tracks closely the order parameter of the charge density wave in the ladder CDW(L), but persists above its transition temperature T(CDW(L)), indicating a strong local pairing above the T(CDW(L)). The 201 meV excitation vanishes in La6Ca8Cu24O(41+δ), and La5Ca9Cu24O41 which are samples with no holes in the ladders. Our results suggest that the doped holes in the ladder are composite bosons consisting of paired holons that order below T(CDW).

Identification of the chromatin regions coated by non-coding Xist RNA

Xist non-coding RNA (ncRNA) is essential for X chromosome inactivation (XCI). Some genes can escape from XCI, but how this occurs is unknown. We developed a modified RNA tagging and recovery of associated proteins (TRAP) method to study the association between Xist RNA and its target genes. In mouse cells, Xist RNA was detected on the Uba1 gene, but not on Jarid1c and Utx genes, which escape from XCI. Using this technique we were able to show that the Xist RNA molecule is not present on active genes that escape from XCI, but is present on genes inactivated by XCI, suggesting that this method is a powerful tool for functional analysis of ncRNA.

Ginsenoside Rg1 restores the impairment of learning induced by chronic morphine administration in rats

Rg1, as a ginsenoside extracted from Panax ginseng, could ameliorate spatial learning impairment. Previous studies have demonstrated that Rg1 might be a useful agent for the prevention and treatment of the adverse effects of morphine. The aim of this study was to investigate the effect of Rg1 on learning impairment by chronic morphine administration and the mechanism responsible for this effect. Male rats were subcutaneously injected with morphine (10 mg/kg) twice a day at 12 hour intervals for 10 days, and Rg1 (30 mg/kg) was intraperitoneally injected 2 hours after the second injection of morphine once a day for 10 days. Spatial learning capacity was assessed in the Morris water maze. The results showed that rats treated with Morphine/Rg1 decreased escape latency and increased the time spent in platform quadrant and entering frequency. By implantation of electrodes and electrophysiological recording in vivo, the results showed that Rg1 restored the long-term potentiation (LTP) impaired by morphine in both freely moving and anaesthetised rats. The electrophysiological recording in vitro showed that Rg1 restored the LTP in slices from the rats treated with morphine, but not changed LTP in the slices from normal saline- or morphine/Rg1-treated rats; this restoration could be inhibited by N-methyl-D-aspartate (NMDA) receptor antagonist MK801. We conclude that Rg1 may significantly improve the spatial learning capacity impaired by chonic morphine administration and restore the morphine-inhibited LTP. This effect is NMDA receptor dependent.

Substrate and chain size dependence of near surface dynamics of glassy polymers

We use nanohole relaxation to study the surface relaxation of films of glassy isotactic poly (methyl methacrylate) (i-PMMA) films. These measurements allow us to obtain the time dependent relaxation function at a number of different sample temperatures for the first 2-3 nm of the free surface in a system often used as a model system for the effect of the substrate on thin film dynamics. The surface is observed to relax at temperatures up to 42 K below the bulk Tg value, even on systems where the thin film Tg is known to be greater than the bulk value. We are able to determine the range over which the substrate directly affects the free surface relaxation, and determine a surprisingly large (Mw independent) limiting thickness of approximately 180 nm where the free surface relaxation is not affected by the substrate. For thick films (h>200 nm) we find an unexpected linear Mw dependence of the near surface relaxation time.

Metformin influences cardiomyocyte cell death by pathways that are dependent and independent of caspase-3

AIMS/HYPOTHESIS

Metformin has been shown to increase fatty acid oxidation, an effect mediated by AMP activated protein kinase (AMPK). We hypothesised that metformin could prevent both caspase-3 activation and apoptosis when induced by palmitic acid.

MATERIALS AND METHODS

Cardiomyocytes were incubated with 1 mmol/l palmitic acid, in the absence or presence of metformin (1-5 mmol/l). Following 1 to 16 h, cell damage was evaluated by measuring lactate dehydrogenase released into the incubation medium, and Hoechst staining. To investigate the mechanism of metformin's effect on cardiomyocytes, substrate utilisation and phosphorylation of AMPK and acetyl-CoA carboxylase were measured. Intracellular mediators of apoptosis were also evaluated.

RESULTS

Incubation of myocytes with palmitic acid for 16 h increased apoptosis, an effect that was partly blunted by 1 and 2 mmol/l metformin. This beneficial effect of metformin was associated with increased AMPK phosphorylation, palmitic acid oxidation and suppression of high-fat-induced increases in (1) long chain base biosynthesis protein 1 levels, (2) ceramide levels, and (3) caspase-3 activity. Unexpectedly, 5 mmol/l metformin dramatically increased apoptosis in myocytes incubated with high fat. This effect was associated with a robust increase in glycolysis, lactate accumulation, and a significant drop of pH in the myocyte incubation medium.

CONCLUSIONS/INTERPRETATION

Our study demonstrates that metformin reduces high-fat-induced cardiac cell death, probably through inhibition of ceramide synthesis. However, at high concentrations, metformin causes proton and lactate accumulation, leading to cell damage that is independent of caspase-3.

The Mouse Genome Database (MGD): from genes to mice--a community resource for mouse biology

The Mouse Genome Database (MGD) forms the core of the Mouse Genome Informatics (MGI) system (http://www.informatics.jax.org), a model organism database resource for the laboratory mouse. MGD provides essential integration of experimental knowledge for the mouse system with information annotated from both literature and online sources. MGD curates and presents consensus and experimental data representations of genotype (sequence) through phenotype information, including highly detailed reports about genes and gene products. Primary foci of integration are through representations of relationships among genes, sequences and phenotypes. MGD collaborates with other bioinformatics groups to curate a definitive set of information about the laboratory mouse and to build and implement the data and semantic standards that are essential for comparative genome analysis. Recent improvements in MGD discussed here include the enhancement of phenotype resources, the re-development of the International Mouse Strain Resource, IMSR, the update of mammalian orthology datasets and the electronic publication of classic books in mouse genetics.

The Mouse Genome Database (MGD): integrating biology with the genome

The Mouse Genome Database (MGD) is one component of the Mouse Genome Informatics (MGI) system (http://www.informatics.jax.org), a community database resource for the laboratory mouse. MGD strives to provide a comprehensive knowledgebase about the mouse with experiments and data annotated from both literature and online sources. MGD curates and presents consensus and experimental data representations of genetic, genotype (sequence) and phenotype information including highly detailed reports about genes and gene products. Primary foci of integration are through representations of relationships between genes, sequences and phenotypes. MGD collaborates with other bioinformatics groups to curate a definitive set of information about the laboratory mouse and to build and implement the data and semantic standards that are essential for comparative genome analysis. Recent developments in MGD discussed here include an extensive integration of the mouse sequence data and substantial revisions in the presentation, query and visualization of sequence data.

Analysis of the mouse transcriptome based on functional annotation of 60,770 full-length cDNAs

Only a small proportion of the mouse genome is transcribed into mature messenger RNA transcripts. There is an international collaborative effort to identify all full-length mRNA transcripts from the mouse, and to ensure that each is represented in a physical collection of clones. Here we report the manual annotation of 60,770 full-length mouse complementary DNA sequences. These are clustered into 33,409 'transcriptional units', contributing 90.1% of a newly established mouse transcriptome database. Of these transcriptional units, 4,258 are new protein-coding and 11,665 are new non-coding messages, indicating that non-coding RNA is a major component of the transcriptome. 41% of all transcriptional units showed evidence of alternative splicing. In protein-coding transcripts, 79% of splice variations altered the protein product. Whole-transcriptome analyses resulted in the identification of 2,431 sense-antisense pairs. The present work, completely supported by physical clones, provides the most comprehensive survey of a mammalian transcriptome so far, and is a valuable resource for functional genomics.

Myosin light chain phosphorylation facilitates in vivo myosin filament reassembly after mechanical perturbation

Phosphorylation of the 20-kDa regulatory myosin light chain (MLC) of smooth muscle is known to cause monomeric myosins in solution to self-assemble into thick filaments. The role of MLC phosphorylation in thick filament formation in intact muscle, however, is not clear. It is not known whether the phosphorylation is necessary to initiate thick filament assembly in vivo. Here we show, by using a potent inhibitor of MLC kinase (wortmannin), that the MLC phosphorylation and isometric force in trachealis muscle could be abolished without affecting calcium transients. By measuring cross-sectional densities of the thick filaments electron microscopically, we also show that inhibition of MLC phosphorylation alone did not cause disassembly of the filaments. The unphosphorylated thick filaments, however, partially dissolved when the muscle was subjected to oscillatory strains (which caused a 25% decrease in the thick filament density). The postoscillation filament density recovered to the preoscillation level only when wortmannin was removed and the muscle was stimulated. The data suggest that in vivo thick filament reassembly after mechanical perturbation is facilitated by the cyclic MLC phosphorylation associated with repeated stimulation.

Enzyme design by chemical modification of protein scaffolds

Covalent modification methods allow an almost unlimited range of functionality to be introduced into proteins. In concert with genetic techniques, chemical strategies have had significant impact in the field of enzyme design. Major recent developments include introducing catalytic activity into inactive proteins, modifying the selectivity and/or reactivity of existing enzymes and designing novel enzyme-based biosensors. New chemical methods promise to further increase the range of functionality that can be incorporated into proteins. These results suggest that semi-synthetic methods will play a key role in the development of future biocatalysts.

An autosomal dominant congenital myopathy with cores and rods is associated with a neomutation in the RYR1 gene encoding the skeletal muscle ryanodine receptor

Central core disease (CCD) and nemaline myopathy (NM) are congenital myopathies for which differential diagnosis is often based on the presence either of cores or rods. Missense mutations in the skeletal muscle ryanodine receptor gene (RYR1) have been identified in some families with CCD. Mutations in the alpha-tropomyosin and alpha-actin genes have been associated with most dominant forms of NM. Analysis of the RYR1 cDNA in a French family identified a novel Y4796C mutation that lies in the C-terminal channel-forming domain of the RyR1 protein. This mutation was linked not only to a severe and penetrant form of CCD, but also to the presence of rods in the muscle fibres and to the malignant hyperthermia susceptibility (MHS) phenotype. The Y4796C mutation was introduced into a rabbit RYR1 cDNA and expressed in HEK-293 cells. Expression of the mutant RYR1 cDNA produced channels with increased caffeine sensitivity and a significantly reduced maximal level of Ca(2+) release. Single-cell Ca(2+) analysis showed that the resting cytoplasmic level was increased by 60% in cells expressing the mutant channel. These data support the view that the rate of Ca(2+) leakage is increased in the mutant channel. The resulting chronic elevation in myoplasmic concentration is likely to be responsible for the severe expression of the disease. Haplotyping analysis indicated that the mutation arose as a neomutation in the proband. This first report of a neomutation in the RYR1 gene has strong implications for genetic linkage studies of MHS or CCD, two diseases characterized by a genetic heterogeneity.

Synthesis of a cationic pyridoxamine conjugation reagent and application to the mechanistic analysis of an artificial transaminase

An N-methylated, cationic pyridoxamine conjugation reagent was synthesized and tethered via a disulfide bond to a cysteine residue inside the cavity of intestinal fatty acid binding protein. The conjugate was characterized and the kinetic parameters compared to its nonmethylated pyridoxamine analogue. Kinetic isotope effects were used for further mechanistic analysis. Taken together, these experiments suggest that a step distinct from deprotonation of the ketimine in the pyridoxamine to pyridoxal reaction is what limits the rate of the artificial transaminase IFABP-Px. However, the internal energetics of reactions catalyzed by the conjugate containing the N-methylated cofactor appear to be different suggesting that the MPx reagent will be useful in future experiments designed to alter the catalytic properties of semisynthetic transaminases.

[The effects of experimental osteoporosis on bone tissues around hydroxyapatite implants]

OBJECTIVE

To investigate the effects of estrogen decreasing on bone tissues around implants in ovariectomized rats.

METHOD

Forty-two female Wistar rats, aged 32 weeks, were used in this study. First, cylindrical hydroxyapatite-coated implants were planted in the proximal part of tibiae of the rats. Then, the rats in experimental group and control group were respectively performed ovariectomy and false surgery after 56 days, the rates were killed in 28, 84 and 168 days after operation, and tibiae were taken out to prepare undecalcified sections. The section were examined by routine histomorphometric measurement and the dynamic changes of trabecular bone and extent of contact between the implants and bone tissue around them.

RESULTS

Twenty-eight days after operation, the density of trabecular bone around the implant in experiment group was found significantly reduced compared with the control group. In the area of cortical bone, no difference was found in the extent of implant-bone contact between two groups, while in the area of spongy bone the extent of contact was different obviously.

CONCLUSION

Ovariectomy in Wistar rats can induce significant osteoporosis around implant, these finding suggest that menopause in women patients may also induce osteoporosis around implanted artificial teeth and affect the prognosis. Therefore, the patients should be carefully observed during the implant treatment course.

Family, peer, and individual correlates of depressive symptomatology among U.S. and Chinese adolescents

This study examined the correlates of symptoms of depressed mood among adolescents in 2 dramatically different cultures (n = 502 in Tianjin, People's Republic of China; n = 201 in greater Los Angeles). Gender, stressful life events, perceived parental warmth, and conflict with parents were associated in the expected direction with depressive symptoms in each cultural setting. As predicted, regression analyses showed that the quality of family relationships and grades in school had significantly stronger associations with depressive symptoms among Chinese youths than among U.S. youths, whereas gender differences in depressive symptoms were greater among the U.S. youths. Peer warmth moderated the effects of particular risk factors for depressive symptoms in each cultural setting.

Artificial metalloenzymes based on protein cavities: exploring the effect of altering the metal ligand attachment position by site directed mutagenesis

In an effort to construct catalysts with enzyme-like properties, we are employing a small, cavity-containing protein as a scaffold for the attachment of catalytic groups. In earlier work we demonstrated that a phenanthroline ligand could be introduced into the cavity of the protein ALBP and used to catalyze ester hydrolysis. To examine the effect of positioning the phenanthroline catalyst at different locations within the protein cavity, three new constructs--Phen60, Phen72 and Phen104--were prepared. Each new conjugate was characterized by UV/vis spectroscopy, fluorescence spectroscopy, guanidine hydrochloride denaturation, gel filtration chromatography, and CD spectroscopy to confirm the preparation of the desired construct. Analysis of reactions containing Ala-OiPr showed that Phen60 catalyzed ester hydrolysis with less selectivity than ALBP-Phen while Phen72 promoted this same reaction with higher selectivity. Reactions with Tyr-OMe were catalyzed with higher selectivity by Phen60 and more rapidly by Phen104. These results demonstrate that both the rates and selectivities of hydrolysis reactions catalyzed by these constructs are dependent on the precise site of attachment of the metal ligand within the protein cavity.

Antibiotic activities and affinities for bacterial cell wall analogue of N-demethylvancomycin and its derivatives

N-Demethylvancomycin, which has been clinically used in China, is one member of vancomycin group (glycopeptide) antibiotics. It differs from vancomycin only in that methyl group on the amino group of the N-terminal residue of vancomycin has been replaced by H. By reductive alkylation of N-demethylvancomycin, we synthesized N-alkyl and N,N'-dialkyl N-demethylvancomycins, which closely correlated with vancomycin in structure. The association constants of the complexes of N-demethylvancomycin and its analogues with di-N-Ac-L-Lys-D-Ala-D-Ala and the antibiotic activity against Staphylococcus aureus of the glycopeptides were determined. Results showed that N-demethylvancomycin has higher affinity for bacterial cell wall analogue di-N-Ac-L-Lys-D-Ala-D-Ala and more potent antibiotic activity against Staphylococcus aureus than vancomycin. Both N-alkylation and N,N'-dialkylation of N-demethylvancomycin reduced the affinity and antibiotic activity. The longer the alkyl groups, the less potent antibiotic activities and lower affinities have the glycopeptides. The antibiotic activities against Staphylococcus aureus of N-demethylvancomycin and its analogues roughly parallel their affinities for di-N-Ac-L-Lys-D-Ala-D-Ala.

The design of protein-based catalysts using semisynthetic methods

The combination of site-directed mutagenesis and chemical modification has resulted in the preparation of protein conjugates with new and useful properties. Proteins modified with metal-chelating groups are proving useful for mapping tertiary and quaternary interactions using the technique of affinity cleavage. The attachment of cofactors, including pyridoxal and pyridoxamine, has resulted in the preparation of semisynthetic transaminases that display enzyme-like properties, including enantioselectivity, substrate specificity and reaction-rate acceleration.

Effects of metal ions on the rates and enantioselectivities of reactions catalyzed by a series of semisynthetic transaminases created by site directed mutagenesis

Fatty acid binding proteins are a class of small 15 kDa proteins with a simple architecture that forms a large solvent sequestered cavity. In previous work, we demonstrated that reductive amination reactions could be performed in this cavity by covalent attachment of a pyridoxamine cofactor and that the rate, enantioselectivity and substrate specificity of these reactions could be altered by site directed mutagenesis. Herein, we show that the chemistry performed by these conjugates can be extended to include catalytic transamination and describe the effects of added metal ions on reaction rate and enantioselectivity. We conclude that metal ions can be used to increase the rate of reactions catalyzed by semisynthetic transaminases; however, the addition of metal ions can also retard the reaction rate. Furthermore, it appears that the presence of metal ions almost always results in an erosion of reaction enantioselectivity. This limits their utility as a practical means of increasing reaction rate. The results reported here, for four independent systems, should be considered in future designs of artificial transaminases.

[Inhalation sedation with nitrous oxide in dental extraction]

OBJECTIVE

To study the advantages of nitrous oxide sedation in teeth extraction.

METHODS

112 patients were randomly allocated to four groups: 1) 60 mmol/L nitrous oxide, 2) 60 mmol/L nitrous oxide with estazolam, 3) 40 mmol/L nitrous oxide, 4) 40 mmol/L nitrous oxide with estazolam. The nitrous oxide was used for conscious sedation as an adjunct to local anaesthesia. 53 patients of control group underwent dental extraction with local anaesthesia only.

RESULTS

The postoperative MDAS scores of experimental group decreased and was significantly superior to control group (P < 0.01). The patients of experimental group showed a certain levels of sedation and partial amnesia. 97 of the 112 patients (86.62%) preferred inhalation sedation with nitrous oxide. There was no difference between the anxiolytic effects, sedative effects, amnestic effects of the four groups (P > 0.05). Estazolam as preoperative medieation did not show obvious coeffect with nitrous oxide.

CONCLUSION

Inhalation sedation with nitrous oxide can provide effects of goodquality antianxiery, sadation, amnesia in dental extraction.

[Oxygen free radical on interleukin-1 activity of hemorrhage/resuscitation rat]

OBJECTIVE

To investigate the effects of oxygen free radical on the enhancement of IL-1 activity in vivo and in vitro on hemorrhagic and resuscitated rat.

METHODS

30% of rats total blood volume was withdraw by carotid artery catheter and resuscitated with 2 times of lost blood volume 1 h later.

RESULTS

Plasm IL-1 activity and MDA content increased and SOD activity decreased significantly 1-4 hours after resuscitation. There was a marked correlation between IL-1 activity and MDA content as well as SOD activity. Treatment with SOD as resuscitation prevented the postresuscitation increase in plasma IL-1 activity significantly. Hemorrhage and resuscitation also caused significant decrease of SOD activity and elevation of MDA in peritoneal macrophage 2 hours after resuscitation. After preincubation with SOD for 1 hour, the macrophage presented a much lowered capacity to release IL-1.

CONCLUSION

Oxygen free radical may be one of the most important factors that contribute to elevation of IL-1 level after hemorrhage and resucitation.

Insulin-like growth factor 1 and parathyroid hormone effects on the growth of fetal rat metatarsal bones cultured in serum-free medium

Insulin-like growth factor 1 (IGF-1) has roles in bone growth, and parathyroid hormone (PTH) is suspected of having effects on bone, perhaps mediated by IGF-1. The purpose of this study was to determine the individual and combined effect of PTH and IGF-1 on fetal long bone metabolism. Three medial metatarsal bones were dissected from Sprague-Dawley rat fetuses harvested at the 19th day of gestation, then grown in serum-free MEM. IGF-1 (group II) or PTH (group PP) were added at the dose of 100 ng/ml for 8 days. In a third group (PI), bones were preincubated for 4 days with PTH followed by a 4-day incubation with IGF-1. Both hormones stimulated endochondral (longitudinal) growth, the highest effect was observed with IGF-1 (II: 3.11 +/- 0.06 vs. 2.16 +/- 0.08 mm in controls). The length elicited by the PI treatment ranged between those measured with IGF-1 (II) and PTH (PP) given alone (PI: 2.80 +/- 0.04 mm; PP: 2.57 +/- 0.06 mm). In addition, both hormones enhanced periosteal growth (endomembranous ossification), as measured by the width of bones (II: 0.39 +/- 0.02 mm; PP: 0.34 +/- 0.02 mm; PI: 0.38 +/- 0.02 vs. 0.29 +/- 0.01 mm in controls). On the other hand, IGF-1 but not PTH caused a significant increase in 35S incorporation (as an indicator of sulfated proteoglycan synthesis in cartilage (percent of incorporating activity; II: 0.18 +/- 0.04%; PI: 0.09 +/- 0.01 vs. 0.03 +/- 0.01% in controls). Nevertheless, both IGF-1 and PTH enhanced osteoblastic activity as shown by increased alkaline phosphatase activity in treated bones (II: 1.18 +/- 0.00 mumol/bone; PP: 0.50 +/- 0.00 vs. 0.28 +/- 0.00 mumol/bone). In conclusion, IGF-1 had the greatest effects on growth in bone length (endochondral osteogenesis) and bone width (intramembranous osteogenesis) and appeared to stimulate both chondrogenesis and osteogenesis. It also increased growth but appeared to have greater effects on osteogenesis than on chondrogenesis. Pretreatment with IGF-1 followed by PTH produced effects that were intermediate between the groups treated with IGF-1 and PTH alone.