A new equation for estimating low-density lipoprotein cholesterol concentration based on machine learning

Low-density lipoprotein cholesterol (LDL-C) is a crucial marker of cardiovascular system damage. In the Chinese population, the estimation of LDL-C concentration by Friedewald, Martin-Hopkins or Sampson equations is not accurate. The aim of this study was to develop a group of new equations for calculating LDL-C concentration using machine learning techniques and to evaluate their efficacy. A total of 182,901 patient samples were collected with standard lipid panel measurements. These samples were collated and randomly divided into a training set and a test set. In the training set, a new equation was constructed using polynomial ridge-regression and compared to the Friedewald, Martin/Hopkins and extended Martin/Hopkins, or Sampson equations in the test set. Subsequently, an additional set of 17,285 patient samples were collected to evaluate the performance of the new equation in clinical practice. The new equation, a ternary cubic equation, was accurate and easy to use, with a goodness-of-fit R2 of 0.9815 and an uncertainty MSE of 37.4250 on the testing set. The difference between the calculated value by the new equation and the measured value of LDL-C was small (0.0424 ± 5.1161 vs Friedewald equation: -13.3647 ± 17.9198, vs Martin/Hopkins and extended Martin/Hopkins equation: -6.4737 ± 8.1036, vs Sampson equation: -8.9252 ± 12.6522, P < .001). It could accurately calculate LDL-C concentration even at high triglyceride and low LDL-C. Furthermore, the new equation could also precisely calculate LDL-C concentration in actual clinical use (R2 = 0.9780, MSE = 24.8482). The new equation developed in this study can accurately calculate LDL-C concentration within the full concentration range of triglyceride and LDL-C, and can serve as a supplement to the direct determination of LDL-C concentration for the prevention, treatment, evaluation, and monitoring of atherosclerotic diseases, compared to the Friedewald, Martin/Hopkins and extended Martin/Hopkins, or Sampson equations.

Active Precipitation of Radiation Belt Electrons Using Rocket Exhaust Driven Amplification (REDA) of Man-Made Whistlers

Ground-based very low frequency (VLF) transmitters located around the world generate signals that leak through the bottom side of the ionosphere in the form of whistler mode waves. Wave and particle measurements on satellites have observed that these man-made VLF waves can be strong enough to scatter trapped energetic electrons into low pitch angle orbits, causing loss by absorption in the lower atmosphere. This precipitation loss process is greatly enhanced by intentional amplification of the whistler waves using a newly discovered process called rocket exhaust driven amplification (REDA). Satellite measurements of REDA have shown between 30 and 50 dB intensification of VLF waves in space using a 60 s burn of the 150 g/s thruster on the Cygnus satellite that services the International Space Station. This controlled amplification process is adequate to deplete the energetic particle population on the affected field lines in a few minutes rather than the multi-day period it would take naturally. Numerical simulations of the pitch angle diffusion for radiation belt particles use the UCLA quasi-linear Fokker Planck model to assess the impact of REDA on radiation belt remediation of newly injected energetic electrons. The simulated precipitation fluxes of energetic electrons are applied to models of D-region electron density and bremsstrahlung X-rays for predictions of the modified environment that can be observed with satellite and ground-based sensors.

Clopidogrel versus ticagrelor in the treatment of Chinese patients undergoing percutaneous coronary intervention: effects on platelet function assessed by platelet function tests and mean platelet volume

Background

Knowledge on the pharmacodynamic effects of antiplatelet drugs including clopidogrel and ticagrelor on Asian patients is scarce. We aim to evaluate the effects of the two drugs on platelet reactivity in the treatment of Chinese patients who underwent percutaneous coronary intervention (PCI), using two platelet function tests (PFT). Meanwhile, the relationship between mean platelet volume (MPV), a routine index of platelet size, and high on-treatment platelet reactivity (HPR) is also investigated.

Methods

Patients receiving dual antiplatelet therapy (DAPT) were scheduled for the assessment of platelet reactivity at 2–3 days after PCI. Two PFTs, light transmission aggregometry (LTA) and vasodilator-stimulated phosphoprotein (VASP)-FCM assay, were applied in the evaluation of platelet reactivity. The MPV was measured simultaneously with EDTA plasma using a Sysmex XN 2000 automated hematology analyzer.

Results

The final study population included the aspirin + clopidogrel group (n = 46) and the aspirin + ticagrelor group (n = 66). In the aspirin + ticagrelor group, the maximal light transmittance (LT) changes in response to 5 μM ADP assessed by LTA was obviously lower than that in the aspirin + clopidogrel group (P <  0.001). The platelet reactivity index (PRI) level in the VASP test was also markedly lower in the group given aspirin and ticagrelor (P <  0.001). There was a significant difference in HPR between the two groups. MPV showed a potent ability to predict the presence of HPR at VASP assay (AUC = 0.788, 95% CI: 0.701–0.875, P <  0.001) in receiver-operating characteristic curve analysis.

Conclusions

Compared with clopidogrel, ticagrelor has dramatically greater antiplatelet effect, with a superiority in suppressing platelet function and a lower HPR rate. In addition, there existed a significant independent association between MPV and high prevalence of HPR in the VASP assay.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00350-2.

FOXN2 suppresses the proliferation and invasion of human hepatocellular carcinoma cells

OBJECTIVE

The aim of this study was to explore the roles of FOXN2 (Fork head Box N2) in mediating the proliferation and invasion of hepatocellular carcinoma (HCC) cells.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to determine expression of FOXN2 in HCC tissues and cells. Transfection of plasmid containing FOXN2 was used to exogenously overexpress FOXN2 in vitro. Cell Counting Kit-8 (CCK-8) assay and transwell assay were applied to detect the proliferation and invasion of HCC cells, respectively.

RESULTS

FOXN2 expression decreased significantly in both HCC tissues and cells (p<0.05). Upregulation of FOXN2 significantly inhibited the proliferation and invasion of HCC cells (p<0.05).

CONCLUSIONS

FOXN2 acts as a regulator in the progression of HCC. Our findings suggest that FOXN2 may be a novel therapeutic monitoring and prognosis biomarker in HCC.

Immunorelated gene polymorphisms associated with acute myeloid leukemia

Although the pathogenesis of acute myeloid leukemia (AML) is still unknown, accumulating evidence has revealed that immune response plays a vital part in the pathogenesis. Here, we investigated the involvement of 21 single nucleotide polymorphisms (SNPs) of immunorelated genes, including cytokines [interleukin (IL)-2, IL-4, IL-9, IL-12A, IL-22, interferon (IFN-α) and transforming growth factor (TGF)-β1], transcriptional regulatory genes (TBX21, STAT1, STAT3, STAT5B, STAT6, GATA3, FOXP3 and IRF4) and others (IL2RA, IL6R, NFKBIA) in 269 AML in-patients and 200 healthy controls. Furthermore, we analyzed the relationship between the SNPs and clinical characteristics. Immunorelated SNP genotyping was performed on the Sequenom MassARRAY iPLEX platform. All the SNPs in healthy controls were consistent with Hardy-Weinberg equilibrium. All final P-values were adjusted by Bonferroni multiple testing. Our results showed that IL-22 (rs2227491) was significantly associated with the white blood cell (WBC) counts. Signal transducer and activator of transcription 5B (STAT-5B) (rs6503691) showed a close relationship with the recurrent genetic abnormalities in patients with AML. We verified the negatively independent effect of age and risk of cytogenetics on overall survival (OS). More importantly, the GG genotype of IL-12A (rs6887695) showed a negative impact on AML prognosis independently. Furthermore, the relative expression of IL-12 was decreased in GG genotype, no matter under a co-dominant or recessive model. However, no correlation was observed between the SNPs mentioned above and disease susceptibility, risk stratification and survival. Our findings suggest that immunorelated gene polymorphisms are associated with prognosis in AML, which may perform as novel inspection targets for AML patients.

Adrenomedullin and adrenotensin regulate collagen synthesis and proliferation in pulmonary arterial smooth muscle cells

To understand the pathophysiological mechanisms of pulmonary arterial smooth muscle cell (PASMC) proliferation and extracellular-matrix accumulation in the development of pulmonary hypertension and remodeling, this study determined the effects of different doses of adrenomedullin (ADM) and adrenotensin (ADT) on PASMC proliferation and collagen synthesis. The objective was to investigate whether extracellular signal-regulated kinase (ERK1/2) signaling was involved in ADM- and ADT-stimulated proliferation of PASMCs in 4-week-old male Wistar rats (body weight: 100-150 g, n=10). The proliferation of PASMCs was examined by 5-bromo-2-deoxyuridine incorporation. A cell growth curve was generated by the Cell Counting Kit-8 method. Expression of collagen I, collagen III, and phosphorylated ERK1/2 (p-ERK1/2) was evaluated by immunofluorescence. The effects of different concentrations of ADM and ADT on collagen I, collagen III, and p-ERK1/2 protein expression were determined by immunoblotting. We also investigated the effect of PD98059 inhibition on the expression of p-ERK1/2 protein by immunoblotting. ADM dose-dependently decreased cell proliferation, whereas ADT dose-dependently increased it; and ADM and ADT inhibited each other with respect to their effects on the proliferation of PASMCs. Consistent with these results, the expression of collagen I, collagen III, and p-ERK1/2 in rat PASMCs decreased after exposure to ADM but was upregulated after exposure to ADT. PD98059 significantly inhibited the downregulation by ADM and the upregulation by ADT of p-ERK1/2 expression. We conclude that ADM inhibited, and ADT stimulated, ERK1/2 signaling in rat PASMCs to regulate cell proliferation and collagen expression.

Associations between Vascular Endothelial Growth Factor Gene Polymorphisms and Susceptibility to Acute Mountain Sickness

Objective:

This study investigated associations between polymorphisms in the vascular endothelial growth factor (VEGF) gene and susceptibility to acute mountain sickness.

Methods:

Two hundred Han Chinese soldiers who developed acute mountain sickness after rapidly ascending to an altitude of < 3600 m and 200 control soldiers (who did not develop the condition) were enrolled in the study. Twelve single nucleotide polymorphisms (SNPs) of the VEGF gene were genotyped in all the study participants. Plasma VEGF concentrations were measured by enzyme-linked immunosorbent assay in 40 subjects with acute mountain sickness and 40 controls before and after exposure to high altitude.

Results:

The frequencies of the rs3025039 genotype and allele were significantly different between the groups. Two SNPs, rs3025039 (which involves a C→T allele variation at position 936 in the 3′ untranslated region) and rs3025030 (which involves a G→C allele variation in the intronic sequence), were associated with a decreased risk of acute mountain sickness.

Conclusion:

The SNPs rs3025039 and rs3025030 of the VEGF gene may be associated with a decreased risk of acute mountain sickness development.

First Report of Leaf Spot Disease Caused by Exserohilum rostratum on Pineapple in Hainan Province, China

Pineapple (Ananas comosus (L.) Merr.) is an important perennial monocotyledonous plant that serves as an important fruit crop globally and is also produced in the Hainan Province of China where production in 2009 was 296,600 t. In July 2009, atypical symptoms of a leaf spot disease were observed on mature pineapple leaves in Chengmai County; approximately 15% of plants propagated from suckers became symptomatic after 150 to 300 days, eventually causing a 3 to 10% yield loss. In the initial infection stage, grayish white-to-yellowish white spots emerged on the leaf surfaces that ranged from 1.0 to 2.4 × 0.3 to 0.7 cm; black specks were not always present in the spots. Leaf spots also had distinctive light brown-to-reddish brown banding pattern on the edges. Several spots would often merge to form large lesions, 6.5 to 15.4 × 2.5 to 5.6 cm, covering more than 67% of the leaf surface, which can lead to death of the plant. Infected pineapple leaves collected from an orchard of Chengmai County were surface sterilized (75% ethanol for 30 s, 0.1% HgCl₂ for 2 min, and rinsed three times in sterile distilled water). Leaf pieces were placed on potato dextrose agar medium and then incubated at 25°C. The emerging fungal colonies were grayish white to brown. Similar strains were obtained from Qionghai City and Wanning City subsequently. Two isolates, ITF0706-1 and ITF0706-2, were used in confirmation of the identity of the pathogen and in pathogenicity tests. Colonies were fast growing (more than 15 mm per day at 25 to 30°C) with dense aerial mycelia. Conidia were fusiform, pyriform to oval or cylindrical, olive brown to dark brown, 3 to 10 septate (typically 5 to 8), 33.2 to 102.5 × 9.0 to 21.3 μm, with a strongly protruding hilum bulged from the basal cell, which were similar to the Type A conidia described by Lin et al. (3). The strains were subjected to PCR amplification of the internal transcribed spacer (ITS)1-5.8S-ITS2 regions with universal primer pair ITS1/ITS4. The ITS sequence comparisons (GenBank Accession Nos. JN711431 and JN711432) shared between 99.60 and 99.83% identity with the isolate CATAS-ER01 (GenBank Accession No. GQ169762). According to morphological and molecular analysis, the two strains were identified as Exserohilum rostratum (Drechs.) Leonard & Suggs. Pathogenicity experiments were conducted five times and carried out by spraying a conidial suspension (10⁵ CFU/ml) on newly matured leaves of healthy pineapple plants; plants sprayed with sterile water served as the negative control. Plants were incubated in the growth chamber at 20 to 25°C. Symptoms of leaf spot developed on test plants 7 days after inoculation while the control plants remained asymptomatic. Koch's postulates were fulfilled with the reisolation of the two fungal strains. Currently, E. rostratum is one of the most common pathogens on Bromeliads in Florida (2) and has been reported on Zea mays (4), Musa paradisiacal (3), and Calathea picturata (1) in China, but to our knowledge, this is the first report of leaf spot disease caused by E. rostratum on pineapple in Hainan Province of P.R. China. References: (1) L. L. Chern et al. Plant Dis. 95:1033, 2011. (2) R. M. Leahy. Plant Pathol. Circ. No. 393. Florida Department of Agriculture and Consumer Services Division of Plant Industry, 1999. (3) S. H. Lin et al. Australas. Plant Pathol. 40:246, 2011. (4) J. N. Tsai et al. Plant Pathol. Bull. 10:181, 2001.

266 THE SHORT TIME TREATMENT WITH SODIUM BUTYRATE ON GERMINAL VESICLE STAGE OOCYTES IMPROVES OOCYTE QUALITY AND DEVELOPMENTAL COMPETENCE IN PIGS

Oocyte maturation is a complex process during which the epigenetic modifications are dramatically changed, especially the histone acetylation and phosphorylation. Sodium butyrate (NaBu) is a histone deacetylase inhibitor that results in a more open structure of DNA. The aim of the present study was to analyse the role of NaBu in the meiosis of porcine oocytes and the subsequent embryonic developmental competence. Cumulus–oocyte complexes (COC) were collected from ovaries obtained at a local slaughterhouse. The COC were randomly divided into 3 groups and matured in vitro in medium (Hao et al. 2006) supplemented with 1 μM NaBu for 2 h [germinal vesicle (GV) stage, group 1] or for 22 h [GV to GV breakdown (GVBD) stage, group 2] or without treatment (control, group 3). After 44 h of in vitro maturation, the oocytes were denuded by 0.2% hyaluronidase, and oocytes with evenly dark ooplasm and visible first polar bodies were considered matured. The cortical granule distribution of matured oocytes was examined with immunostaining. The relative expression of CyclinB and Cdc2 of 3 group oocytes was determined with real-time PCR. Some matured oocytes from each group were collected and stimulated with electric pulse (2 direct current pulses of 1.2 kV cm–1 for 30 μs). The rate of parthenogenetic blastocyst was recorded, and cell number of each blastocyst was determined under an inverted fluorescence microscope after staining with 10 μg mL–1 of Hoechst 33342. The following results were found. 1) Compared with the control group (n = 70, 67.74 ± 1.64), oocyte maturation rates of group 1 and group 2 decreased significantly along with the extended treatments (n = 70, 59.57 ± 5.29 and 46.99 ± 1.22, respectively; P < 0.05). 2) The long time (22 h) treatment with NaBu inhibited the developmental competence (blastocyst rate) of oocytes (n = 30, 15.33 ± 3.47 v. 27.16 ± 2.10 P < 0.05), and the short time (2 h) treatment with NaBu on GV-stage oocytes inhibited the meiotic process slightly but improved the blastocyst rate (n = 30, 33.93 ± 2.51 v. 27.16 ± 2.10; P < 0.05). 3) The short time (2 h) treatment resulted in the migration of more cortical granules into the plasmasmic membrane and formed a monolayer with the membrane (compared with the control). 4) The exposure to NaBu from GV to GVBD stage induced the expression of the CyclinB and Cdc2 in the matured oocytes (4.68 ± 0.45 and 5.80 ± 0.58, respectively; P < 0.05) compared with the control. 5) Short time (2 h) exposure to NaBu on GV-stage oocytes inhibited the expression of the Cdc2 but increased the expression of the CylinB in the matured oocytes (0.43 ± 0.06 and 1.65 ± 0.26, respectively; P < 0.05) compared with the control. In conclusion, results of this study demonstrate that exposure to NaBu inhibits porcine oocyte meiosis in proportion to treatment length. However, a 2-h treatment with 1 μM NaBu improves oocyte developmental competence to the blastocyst stage. These results are useful for improving the developmental competent of oocytes for IVF and in vitro embryo production. This work was supported by a grant (No. 2009CB941001) from the National Basic Research Program of China.

Impact of functional bowel symptoms on quality of life and fatigue in quiescent Crohn disease and irritable bowel syndrome

BACKGROUND

Patients with irritable bowel syndrome (IBS) and Crohn disease (CD) have impaired quality of life (Qol) associated with fatigue. Whether IBS-like symptoms have a similar impact on Qol and fatigue in quiescent CD than in IBS is currently unknown. Our aims were (i) to evaluate the prevalence of IBS-like symptoms in quiescent CD and (ii) to compare the impact of IBS-like symptoms on Qol and fatigue in both diseases.

METHODS

A total of 92 quiescent CD, 40 IBS and 20 healthy subjects similar in age were included prospectively in five French academic centers. IBS symptoms were evaluated through the Rome III criteria. The severity of IBS symptoms, Qol, fatigue, depression and anxiety was measured using questionnaires (Francis Score, Likert scales, Fatigue Impact Scale, short-form Beck and Hospital Anxiety and Depression Scale).

KEY RESULTS

Irritable bowel syndrome-like symptoms were found in 42/92 (45.6%) patients with quiescent CD. The presence of IBS-like symptoms was associated with significant more profound alterations of Qol, high scores of fatigue, depression, but similar levels of anxiety. Compared to CD patients with IBS-like symptoms, IBS patients had more severe gastrointestinal symptoms and alterations of Qol, but similar scores of fatigue, depression and anxiety. In quiescent CD patients, fatigue was independently associated with the presence of IBS-like symptoms (OR = 1.018, 95% CI: 1.002-1.034, P = 0.02).

CONCLUSIONS & INFERENCES

The prevalence of IBS-like symptoms is elevated in quiescent CD. The presence of IBS-like symptoms in quiescent CD is probably associated with the range of fatigue/depression disorders. The mechanism underlying the occurrence of IBS-like symptoms in quiescent CD needs to be further explored.

Survey of heavy metal pollution and assessment of agricultural soil in Yangzhong district, Jiangsu Province, China

We investigated concentrations of Hg, Cd, Pb, Zn, Cu, As, Ni, and Cr in samples of soil, cereal, and vegetables from Yangzhong district, China. Compared to subsoils, the sampled topsoils are enriched in Hg, Cd, Cu, Pb, Zn, and As. High levels of Cd and Hg are observed in most agricultural soils. Concentrations of Cr and Ni show little spatial variation, and high Cu, Pb, and Zn contents correspond well to areas of urban development. High As contents are primarily recorded at the two ends of the sampled alluvion. The contents of Cd, Hg, and total organic carbon (TOC) increase gradually to maximum values in the upper parts of soil profiles, while Cr and Ni occur in low concentrations within sampled profiles. As, Pb, Cu, and Zn show patterns of slight enrichment within the surface layer. Compared to data obtained in 1990, Cd and Hg show increased concentrations in 2005; this is attributed to the long-term use of agrochemicals. Cr and Ni contents remained steady over this interval because they are derived from the weathering of parent material and subsequent pedogenesis. The measured As, Cu, Pb, and Zn contents show slight increases over time due to atmospheric deposition of material sourced from urban anthropogenic activity. Low concentrations of heavy metals are recorded in vegetables and cereals because the subalkaline environment of the soil limits their mobility. Although the heavy metal concentrations measured in this study do not pose a serious health risk, they do affect the quality of agricultural products.

Association of the spectral features of heart period signal with SNP of NOS in the Chinese Han nationality population

To explore association of the spectral features of heart period signal with SNPs at 5 sites of NOS gene in the subjects (male89, female77, aged 62.40+/-2.5 yrs) by allele specific primer PCR technique. It was found that the TT allelic genotype of NOS2 C-1173T associated with the highest RPH and TT allelic genotype of NOS3 G894T associated with the highest APH in HPS spectral parameters. This suggests the SNPs of NOS2 C-1173T and NOS3 G894T may be the deep layer factors to result in the variability of HPS spectral parameters.

Metabolism of O6-propyl and N6-propyl-carbovir in CEM cells

The metabolism of O6-propyl-carbovir and N6-propyl-carbovir, two selective inhibitors of HIV replication, has been evaluated in CEM cells. Both compounds were phosphorylated in intact cells to carbovir-5'-triphosphate. The metabolism of these two agents was inhibited by deoxycoformycin and mycophenolic acid, but not erythro-9-(2-hydroxy-3-nonyl)adenine. No evidence of the 5'-triphosphate of either compound was detected in CEM cells.

Substrate specificity of human glycinamide ribonucleotide transformylase

The nucleotide substrate specificity of human glycinamide ribonucleotide transformylase, a chemotherapeutic target, has been examined. The enzyme accepts the sarcosyl analog of glycinamide ribonucleotide, carbocyclic glycinamide ribonucleotide, and two phosphonate derivatives of carbocyclic glycinamide ribonucleotide with V/K values, relative to that obtained for beta-glycinamide ribonucleotide, of 1, 27, 1.4, and 2.9%, respectively. Several other analogs of carbocyclic glycinamide ribonucleotide, namely a truncated phosphonate and 2',3'-dideoxy- and 2',3'-dideoxy-2',3'-didehydro-carbocyclic glycinamide ribonucleotide, were inhibitors of the enzyme, competitive against glycinamide ribonucleotide, with Ki values approximately 100 times higher than the Km for -glycinamide ribonucleotide. Although the results of the present study parallel those obtained previously with the avian enzyme (V. D. Antle, D. Liu, B. R. McKellar, C. A. Caperelli, M. Hua, and R. Vince (1996) J. Biol. Chem. 271, 6045-6049), quantitative differences between the two enzyme species have been uncovered.

"First aid for scalds" campaign: reaching Sydney's Chinese, Vietnamese, and Arabic speaking communities

OBJECTIVES

As a serious yet preventable problem, scald injuries in children have been a priority for prevention in Australia and other developed countries. Not only can the occurrence of scalds be prevented, but immediate first aid treatment offers an effective method for secondary prevention, reducing the severity of scalds. Despite the success of scald prevention initiatives, local evidence suggested that first aid knowledge was lacking in some minority ethnic groups. To redress this gap, the "First Aid for Scalds" campaign for those from a non-English speaking background was specifically targeted to three ethnic groups (Vietnamese, Chinese, and Arabic), with the aim of increasing the proportions of parents and caregivers who had correct knowledge of first aid treatment for scalds. The primary strategy was a media campaign, including advertisements on ethnic radio and in ethnic newspapers.

METHODS

The evaluation design included formative research and impact evaluation. The impact evaluation study involved random population based telephone surveys with each of the three language groups, before and after the campaign, to assess the reach and effectiveness of the campaign.

RESULTS

After the campaign, there were significant increases in the proportion of people who knew the correct first aid treatment for scalds. There were substantial variations in campaign recall and knowledge between each of the three language groups. The largest improvement was found in the Vietnamese group.

CONCLUSION

The association between campaign recall and increase in correct knowledge, and the absence of any similar interventions during the campaign period, give credence to the conclusion that the changes observed were a result of the campaign. The results demonstrate the value of community based injury prevention campaigns specifically targeting linguistically diverse communities.

Cervical screening among immigrant Vietnamese women seen in general practice: current rates, predictors and potential recruitment strategies

OBJECTIVE

To ascertain cervical screening rates among Vietnamese women attending Vietnamese-speaking general practitioners (GPs) in Sydney, their recall of opportunistic recruitment by these GPs and their preferences for strategies to encourage screening.

METHOD

Women born in Vietnam aged 18-69 years were recruited through the waiting room of their GP and completed questionnaires in either Vietnamese or Chinese before and after their consultation.

RESULTS

Of 355 women seen during the survey period, 170 were ineligible. Of those eligible, 118 women (64% response rate) completed waiting room questionnaires. Of 86 women 'at risk', 56 (65%) reported having a cervical smear within two years or due on that day; 26 (86%) of those 30 women overdue for screening reported visiting a GP at least twice in the past six months. After adjustment for age and education, women who were more acculturated or had resided in Australia for the most years remained significantly more likely to be screened (p = 0.027 and p = 0.037 respectively). In the follow-up questionnaire, returned by 49 women (52%) who agreed to receive it, recall of opportunistic advice from the GP was low. Female GPs, free screening and more information in Vietnamese were the three most popular recruitment strategies.

CONCLUSION

Study confirms low participation rates in cervical screening by Vietnamese women using self-report. Recent immigrants and the least acculturated are least likely to be screened.

IMPLICATIONS

A community-based strategy involving Vietnamese-speaking GPs shows promise, inviting behavioural evaluation.

Free split and segmental latissimus dorsi muscle transfer in one stage for facial reanimation

The authors report the experience in facial reanimation using free innervated split and segmental latissimus dorsi muscle flap one-stage transfer in 86 patients with longstanding facial palsy. The segmental latissimus dorsi was taken from the distal part of the muscle so that the muscle flap had an ultra-long neurovascular pedicle of 13 to 17.5 cm in length. The muscle flap was made thinner by splitting the segmental muscle. The split segmental muscle flap was transferred to the paralyzed side of the face with its ultra-long neurovascular pedicle passing through a tunnel in the upper lip to the normal side of the face. The neurovascular pedicle of the muscle flap was anastomosed with the facial nerve, artery, and veins, respectively, on the normal side of the face. The operation was designed without the cross-facial nerve graft stage. From 1986 to October of 1997, 86 patients with long-standing facial paralysis were treated in our department. The duration of facial palsy in this series ranged from 1.5 to 51 years. A satisfactory result was obtained in 80 cases, evaluated at 8 months to 2 years postoperatively. The expression movement of the soft tissues of the face can be seen not only over transferred muscle but also on the paralyzed muscle covered by the splitting muscle flap. It is supposed that this is the result of muscle-muscle neurolization. Study of 66 specimens of latissimus dorsi muscle in the cadavers is discussed.

Heterozygous osteopetrotic (op) mutation reduces atherosclerosis in LDL receptor- deficient mice

Previous studies of osteopetrotic (op) mice lacking macrophage colony-stimulating factor (M-CSF) have revealed an inhibition of atherosclerosis development in the apolipoprotein E (apo E)-deficient model and in a diet-induced model. Using LDL receptor-deficient mice, we now show that atheroma development depends on M-CSF concentration, as not only did homozygous osteopetrotic (op/op) mice have dramatically reduced lesions (approximately 0.3% of control lesion size) but heterozygous (op/+) mice had lesions < 1% of controls. Mice heterozygous for the op mutation (op/+) had plasma levels of M-CSF about half those in controls (+/+). The finding that an approximately 2-fold reduction in M-CSF expression reduced lesion size approximately 100-fold suggests the requirement for a threshold level of M-CSF. The effect of M-CSF on atherosclerosis did not appear to be mediated either by changes in plasma lipoprotein levels or alterations in the number of circulating monocytes, since both op/op and op/+ mice exhibited higher levels of atherogenic lipoprotein particles and (op/+) mice showed a near normal number of circulating monocytes. LDL receptor-null littermates of genotypes from op/op, op/+, to +/+ showed monocyte differentials of approximately 4.5, 8, and 10%, respectively. Taken together, these results suggest that the effects of M-CSF on atherogenesis may not be mediated by expression of M-CSF systemically or by modulation of the number of circulating monocytes. These studies support the conclusion that M-CSF participates critically in fatty streak formation and progression to a complex fibrous lesion.

Decrease of very late activation antigen-4 and CD36 on reticulocytes in sickle cell patients treated with hydroxyurea

Sickle cell disease (SCD) is characterized by repeated vaso-occlusive events, which result in substantial morbidity. Abnormal adhesion of sickle red blood cells (RBC) to the vascular endothelium is postulated to play a role in the pathogenesis of vaso-occlusion. Two adhesion receptors, very late activation antigen-4 (VLA-4) and CD36, are found in unusually high numbers on sickle cell reticulocytes and do mediate adhesion of sickle RBC to endothelium. Hydroxyurea (HU) therapy results in fewer vaso-occlusive episodes, and we postulated that HU-related modulation of VLA-4 and CD36 receptors may contribute to its clinical benefit. Using flow cytometry, eight patients were followed from the onset of HU treatment through a mean treatment length of 200 +/- 49 days. Mean corpuscular volume and percent fetal hemoglobin (Hb F) increased from 87% +/- 6% to 98% +/- 9% and 6.6% +/- 3.9% to 12.7% +/- 5.6%, respectively. The percentage of reticulocytes expressing VLA-4 decreased from 29.0% +/- 5.9% to 14.9% +/- 2.3% (P = .0003). Two thirds of the total decrease in VLA-4 expression occurred after 10 weeks of HU and plateaued by 20 weeks. Changes in VLA-4 expression occurred before substantial increases in Hb F. The percentage of reticulocytes expressing CD36 decreased from 55.3% +/- 6.4% to 42.6% (P = .0046). Changes in adhesion receptor expression were not caused by a decrease in reticulocytosis with HU therapy. This report is the first to associate a decrease in adhesion receptor expression with a therapy known to reduce the clinical severity of SCD.

Substrate specificity of glycinamide ribonucleotide synthetase from chicken liver

Several analogs of glycinamide ribonucleotide and phosphoribosylamine have been prepared and evaluated as substrates for glycinamide ribonucleotide synthetase purified from chicken liver. Glycinamide ribonucleotide analogs include side chain modifications wherein the glycine side chain (R = CH2NH2) has been replaced by R = CH2NHCH3 and R = CH2CH2NH2, ribose ring replacement by chiral cyclopentane and cyclopentene derivatives, and phosphate replacement by phosphonates. All of these, with the exception of the O-phosphonate, served as substrates for the reverse enzymatic reaction, with Vmax values comparable to that obtained with glycinamide ribonucleotide, although the Km values ranged from 21 to 118 times the Km for glycinamide ribonucleotide. Analogs of phosphoribosylamine examined as substrates for the forward reaction consist of chiral derivatives of cyclopentane and cyclopentene and a chiral carbocyclic phosphonate. These also served as substrates, with Km values ranging from 5 to 23 times the Km for phosphoribosylamine and with diminished Vmax values. These studies have begun to define the structural features of the nucleotide substrate necessary to support enzymatic activity. Sarcosine (N-methylglycine) and beta-alanine were also accepted as substrates, albeit with reduced affinity compared with glycine.

Substrate specificity of glycinamide ribonucleotide transformylase from chicken liver

Several glycinamide ribonucleotide analogs have been prepared and evaluated as substrates and/or inhibitors of glycinamide ribonucleotide transformylase from chicken liver. The side chain modified analogs, in which the glycine side chain, R = CH2NH2, has been replaced by R = CH2NHCH3 and R = CH2CH2NH2, are substrates, with V/K (relative intensity) of 2.4% and 16.3%, respectively. Several carbocyclic analogs of glycinamide ribonucleotide, including the phosphonate derivative of carbocyclic glycinamide ribonucleotide, did not serve as substrates, but were inhibitors of the enzyme, competitive against glycinamide ribonucleotide, with Ki values ranging from 7.4 to 23.6 times the Km for glycinamide ribonucleotide. However, the O-phosphonate analog of carbocyclic glycinamide ribonucleotide did support enzymatic activity, with V/K (relative intensity) of 0.8%. In addition, glycinamide ribonucleoside was neither a substrate for, nor an inhibitor of, glycinamide ribonucleotide transformylase. Furthermore, alpha-glycinamide ribonucleotide had no effect on enzyme activity. These studies have begun to define the structural features of the nucleotide substrate required to support enzymatic activity.

Detection of altered membrane phospholipid asymmetry in subpopulations of human red blood cells using fluorescently labeled annexin V

The phospholipids of the human red cell are distributed asymmetrically in the bilayer of the red cell membrane. In certain pathologic states, such as sickle cell anemia, phospholipid asymmetry is altered. Although several methods can be used to measure phospholipid organization, small organizational changes have been very difficult to assess. Moreover, these methods fail to identify subpopulations of cells that have lost their normal phospholipid asymmetry. Using fluorescently labeled annexin V in flow cytometry and fluorescent microscopy, we were able to identify and quantify red cells that had lost their phospholipid asymmetry in populations as small as 1 million cells. Moreover, loss of phospholipid organization in subpopulations as small as 0.1% of the total population could be identified, and individual cells could be studied by fluorescent microscopy. An excellent correlation was found between fluorescence-activated cell sorter (FACS) analysis results using annexin V to detect red cells with phosphatidylserine (PS) on their surface and a PS-requiring prothrombinase assay using similar red cells. Cells that bound fluorescein isothiocyanate (FITC)-labeled annexin V could be isolated from the population using magnetic beads covered with an anti-FITC antibody. Evaluation of blood samples from patients with sickle cell anemia under oxygenated conditions demonstrated the presence of subpopulations of cells that had lost phospholipid asymmetry. While only a few red cells were labeled in normal control samples (0.21% +/- 0.12%, n = 8), significantly increased (P < .001) annexin V labeling was observed in samples from patients with sickle cell anemia (2.18% +/- 1.21%, n = 13). We conclude that loss of phospholipid asymmetry may occur in small subpopulations of red cells and that fluorescently labeled annexin V can be used to quantify and isolate these cells.

Possible contribution of a glutathione conjugate to the long-duration action of beta-funaltrexamine

The fumaramate derivative of naltrexone, beta-funaltrexamine (beta-FNA), is a highly selective long-lasting mu opioid receptor antagonist that is active both in vitro and in vivo, presumably as a result of covalent binding to a mu receptor-based sulfhydryl group. Glutathione, which occurs in significant levels in brain and liver, was found to undergo a Michael-type reaction with beta-FNA in the test tube to give a stable conjugate 3 which occurred as an isomeric mixture. When tested in the GPI and MVD smooth muscle preparations, 3 was found to possess one-tenth the agonist activity of beta-FNA is both tissues, but showed no irreversible antagonist activity. The same result was found for the cysteine conjugate 4, except for some irreversible antagonism in the MVD. Both conjugates antagonize the antinociceptive effect of morphine in the mouse radiant heat tail-flick assay on icv administration. This antagonism persisted and actually increased over 24 h and generally paralleled the duration profile of beta-FNA. On sc administration, beta-FNA and 3 showed similar duration of antagonistic effect, while 4 exhibited only marginal activity at the early time interval. When the compounds are compared by the dose to produce equivalent antagonism, beta-FNA and 3 appeared equally effective and accessible by either route, whereas 4 showed a large difference between the two routes. It is possible that the ultra-long antagonism of the conjugates may result from their enzymatic conversion to beta-FNA in the central nervous system in view of the fact that conjugate 5, which cannot be converted to beta-FNA, did not produce antagonism of long duration in vivo. Alternatively, the protracted antagonism could arise from sequestration of 3 and 4 in tissue compartments that interface with mu opioid receptors.

Terraforming Mars: dissolution of carbonate rocks by cyanobacteria

One of the most difficult tasks in terraforming Mars is the release into the atmosphere of CO2 bound by the surface of Mars. Even if a sufficiently dense CO2 atmosphere can be created by appropriate technology, the maintenance of CO2 concentration remains a problem. As Mars lacks plate tectonics as well as active volcanism, an Earth-like carbon cycle cannot be reproduced there. We suggest that Matteia sp., a lime-boring cyanobacterium isolated from Negev desert rocks, be used to dissolve carbonate rocks both for initial release of CO2 and in design of a Martian carbon cycle.

The effects of intracerebroventricular injection of naloxone, phentolamine and methysergide on the transmission of nociceptive signals in rat dorsal horn neurons with convergent cutaneous-deep input

In anaesthetized rats, recordings were made from nociceptive dorsal horn neurons with convergent input from the skin and deep somatic tissues. The results of a previous study have shown that in these neurons the input from deep nociceptors is subjected to a much stronger tonic descending inhibition than is the input from cutaneous nociceptors. The aim of the present study was to find out whether at supraspinal levels opioidergic, adrenergic, or serotoninergic transmitters are involved in this quite specific inhibition of deep nociception. Injections of naloxone, phentolamine, and methysergide into the third ventricle showed that only naloxone is capable of abolishing the tonic inhibition of the deep nociceptive input to spinal neurons. The input from cutaneous nociceptors to the same cells was largely unaffected by naloxone. Thus the effects of intracerebroventricular injection of naloxone resembled those obtained with a spinal cold block in a previous study; with the exception that the increase in background activity--which is prominent during cold block--was missing after the injection of naloxone. The present results demonstrate that the tonic descending inhibition of the deep nociception operates with opioidergic synapses at the supraspinal level. In contrast, supraspinal adrenergic and serotoninergic mechanisms do not appear to contribute to the tonic inhibition. The data confirm and extend previous results which suggested that a particular portion of the descending antinociceptive system may act mainly on the input from deep nociceptors. Pharmacologically, this particular portion seems to be opioidergic in nature.

Synthesis and anti-HIV activity of carbocyclic 2',3'-didehydro-2',3'-dideoxy 2,6-disubstituted purine nucleosides

(+-)-cis-[4-[(2,5-Diamino-6-chloropyrimidinyl)amino]-2- cyclopentenyl]carbinol (5a) was synthesized from 2-amino-4,6-dichloropyrimidine and cis-4-(hydroxymethyl)cyclopentenylamine (2a) by subsequent preparation of the 5-[(4-chlorophenyl)azo] derivative of the resulting pyrimidine (3a) and reduction of the azo moiety with zinc and acetic acid. The carbocyclic analogue of 2',3'-didehydro-2',3'-dideoxy 2-amino-6-chloropurine (6a) and the corresponding 8-azapurine (9a) were prepared from 5a. The carbocyclic 2',3'-didehydro-2',3'-dideoxy analogues of guanine (7a) and 2,6-diaminopurine (8a), and 8-azaguanine (10a) and 8-aza-2,6-diaminopurine (11a) were prepared from 6a and 9a, respectively. The corresponding 2',3'-saturated series of 2-amino-6-substituted-purine carbocyclic nucleosides was prepared following the same scheme starting with cis-4-(hydroxymethyl)cyclopentylamine (2b). Carbocyclic 2',3'-didehydro-2',3'-dideoxyguanosine (carbovir, 7a) emerged as a potent and selective anti-HIV agent. Its hydrolytic stability and its ability to inhibit the infectivity and replication of HIV in T-cells at concentrations of approximately 200-400-fold below toxic concentrations make carbovir an excellent candidate for development as a potential antiretroviral agent.

Liquid chromatographic assay of carbovir, a carbocyclic nucleoside active against human immunodeficiency virus

Carbovir is a novel carbocyclic guanosine derivative that has potent in vitro activity against human immunodeficiency virus, the causative agent of acquired immunodeficiency syndrome (AIDS). Two methods of sample preparation were developed for the analysis of carbovir in rat blood. Solid-phase extraction on C18 extraction columns proved to be the most effective. Whole rat blood (200 microliters) was diluted with 0.8 ml of distilled water containing the internal standard. After two freeze-thaw cycles to lyse the red blood cells and subsequent centrifugation at 13,000 g, the supernatant was loaded on the C18 extraction columns. Carbovir and the internal standard were eluted with methanol-water (60:40). The extract was evaporated and reconstituted in mobile phase and the samples were injected onto a high-capacity reversed-phase column. The compounds were detected at 252 nm. Other nucleosides that could be used in the treatment of AIDS such as zidovudine and acyclovir did not interfere. Standard curves were linear over the concentration range 0.156-28.0 micrograms/ml (r2 greater than 0.99). The within-day coefficient of variation was less than 7.6% at all concentrations (n = 4). The between-day coefficient of variation ranged from 16.7 to 2.0% (n = 14). The limit of sensitivity was 0.05 micrograms/ml with a 200-microliters blood sample and the average extraction recovery was 74%. Carbovir was stable in rat blood for at least 4 h at 37 degrees C. The assay was used to determine the blood levels of carbovir in a rat after a 20 mg/kg intravenous dose.

Pharmacokinetics and bioavailability of carbovir, a carbocyclic nucleoside active against human immunodeficiency virus, in rats

Carbovir is a novel carbocyclic nucleoside which has been shown to have potent in vitro activity against human immunodeficiency virus, the causative agent of acquired immunodeficiency syndrome. Sprague-Dawley male rats were used to investigate the pharmacokinetics and bioavailability of carbovir. Six rats received carbovir (20 mg/kg of body weight) through the jugular vein, and blood samples were collected through the femoral vein 2, 5, 10, 15, 20, 30, 45, 60, 75, 90, 120, 150, 180, and 240 min after the dose. Four of these rats also received a 60-mg/kg oral dose of carbovir, and a similar blood sampling schedule was followed. Whole-blood samples were prepared by solid-phase extraction, and the carbovir concentration in the samples was analyzed by reversed-phase high-pressure liquid chromatography. The profile of carbovir concentration in blood versus time after the intravenous dose was biexponential, with a very rapid distribution phase. Terminal elimination half-life was 21.4 +/- 4.37 min, and total body clearance was 55.2 +/- 13.8 ml/min per kg, which was within the range of the hepatic blood flow. The volume of distribution at steady state was 1,123 +/- 250 ml/kg. The blood/plasma ratio and the plasma protein binding of carbovir in rat blood were determined in vitro by ultrafiltration. The plasma protein binding of carbovir was only 20% and was not concentration dependent. However, the blood/plasma ratio decreased significantly as concentration increased, indicating saturable binding sites in erythrocytes. After the oral dose, the terminal half-life was 81.0 +/- 67.6 min, indicating that oral carbovir followed "flip-flop" kinetics, with absorption being much slower than elimination of the drug from the body. Oral bioavailability was 0.101 +/- 0.035. Double peaks were present in the concentration-time profile for each rat receiving the oral dose, indicating either a delay in stomach emptying of the drug or slow dissolution of precipitated carbovir in the stomach and upper small intestine.

Potent and selective activity of a new carbocyclic nucleoside analog (carbovir: NSC 614846) against human immunodeficiency virus in vitro

Carbocyclic 2',3'-didehydro-2',3'-dideoxyguanosine (Carbovir: NSC 614846), a novel nucleoside analog, emerged as a potent and selective anti-HIV agent from a large screening program conducted by the National Cancer Institute and its contractors. Its hydrolytic stability and its ability to inhibit the infectivity and replication of HIV in T-cells at concentrations of approximately 200- to 400-fold below toxic concentrations make carbovir a top-priority candidate for development as a potential antiretroviral agent in the treatment of AIDS patients.

Cryptoendolithic lichen and cyanobacterial communities of the Ross Desert, Antarctica

Cryptoendolithic microbial communities in the Ross Desert (McMurdo Dry Valleys) are characterized on the basis of photosynthetic microorganisms and fungi. Two eukaryotic communities (the lichen-dominated and Hemichloris communities) and three cyanobacterial communities (the red Gloeocapsa, Hormathonema-Gloeocapsa, and Chroococcidiopsis communities) are described. Eleven coccoid, one pleurocapsoid, and five filamentous cyanobacteria occurring in these communities are characterized and illustrated. The moisture grade of the rock substrate seems to affect pH, formation of primary iron stain, and the distribution of microbial communities.

Synthesis and biological evaluation of acyclic neplanocin analogues

Acyclic neplanocin analogues were prepared by condensation of adenine or N2-acetylguanine with (E)-1,4-dichlorobut-2-ene and subsequent hydrolysis. The N-9-substituted product 9-[(E)-4-hydroxybut-2-enyl]adenine was obtained when adenine was employed as the starting purine, while N2-acetylguanine yielded both the N-7 and N-9 isomers. Cell-culture studies revealed that only the chloro-substituted intermediate 9-[(E)-4-chlorobut-2-enyl]adenine exhibited significant cytotoxicity against P-388 mouse lymphoid leukemia cells, while the N-9-substituted guanine analogue 9-[(E)-4-hydroxybut-2-enyl]guanine inhibited replication of herpes simplex viruses type 1 and type 2.