Serum uric acid and cardiovascular mortality the NHANES I epidemiologic follow-up study, 1971-1992. National Health and Nutrition Examination Survey

CONTEXT

Although many epidemiological studies have suggested that increased serum uric acid levels are a risk factor for cardiovascular mortality, this relationship remains uncertain.

OBJECTIVE

To determine the association of serum uric acid levels with cardiovascular mortality.

DESIGN AND SETTING

Cross-sectional population-based study of epidemiological follow-up data from the First National Health and Nutrition Examination Survey (NHANES I) from 1971-1975 (baseline) and data from NHANES I Epidemiologic Follow-up Study (NHEFS).

PARTICIPANTS

A total of 5926 subjects who were aged 25 to 74 years and had serum uric acid level measurements at baseline.

MAIN OUTCOME MEASURES

Ischemic heart disease mortality, total cardiovascular mortality, and all-cause mortality, compared by quartiles of serum uric acid level.

RESULTS

In an average of 16.4 years of follow-up, 1593 deaths occurred, of which 731 (45.9%) were ascribed to cardiovascular disease. Increased serum uric acid levels had a positive relationship to cardiovascular mortality in men and women and in black and white persons. Deaths due to ischemic heart disease in both men and women increased when serum uric acid levels were in the highest quartile compared with the lowest quartile (men, >416 vs <321 micromol/L; risk ratio, 1.77 [95% confidence interval [CI], 1.08-3.98]; women, >333 vs <238 micromol/l; risk ratio, 3.00 [95% CI, 1.45-6.28]). Cox regression analysis showed that for each 59.48-micromol/L increase in uric acid level, cardiovascular mortality and ischemic heart disease mortality increased. Hazard ratios for men were 1.09 (95% CI, 1.02-1.18) and 1.17 (95% CI, 1.06-1.28), and for women were 1.26 (95% CI, 1.16-1.36) and 1.30 (95% CI, 1.17-1.45), respectively, after adjustment for age, race, body mass index, smoking status, alcohol consumption, cholesterol level, history of hypertension and diabetes, and diuretic use. Further analysis, stratifying by cardiovascular risk status, diuretic use, and menopausal status, confirmed a significant association of uric acid and cardiovascular mortality in all subgroups except among men using diuretics (n=79) and men with 1 or more cardiovascular risk factors (n=1140).

CONCLUSION

Our data suggest that increased serum uric acid levels are independently and significantly associated with risk of cardiovascular mortality.

Avian leukosis virus-induced tumors have common proviral integration sites and synthesize discrete new RNAs: oncogenesis by promoter insertion

Unlike other RNA tumor viruses, avian leukosis viruses (which cause lymphomas and occasionally other neoplasms) lack discrete "transforming genes". We have analyzed the virus-related DNA and RNA of avian leukosis virus (ALV)-induced tumors in an attempt to gain insight into the mechanism of ALV oncogenesis. Our results show that viral gene products are not required for maintenance of neoplastic transformation. Primary and metastatic tumors are clonal and thus presumably derived from a single infected cell. Most importantly, tumors from different birds have integration sites in common. Tumor cells synthesize discrete new poly(A) RNAs consisting of viral sequences covalently linked to cellular sequences. These RNA species are expressed at high levels in tumor cells. Our results suggest that in lymphoid tumors, an ALV provirus is integrated adjacent to a specific cellular gene, and the insertion of the viral promoter adjacent to this gene results in its enhanced expression, leading to neoplasia. These results have potentially important implications for the mechanism of non-viral carcinogenesis.

Changes in forest biomass carbon storage in China between 1949 and 1998

The location and mechanisms responsible for the carbon sink in northern mid-latitude lands are uncertain. Here, we used an improved estimation method of forest biomass and a 50-year national forest resource inventory in China to estimate changes in the storage of living biomass between 1949 and 1998. Our results suggest that Chinese forests released about 0.68 petagram of carbon between 1949 and 1980, for an annual emission rate of 0.022 petagram of carbon. Carbon storage increased significantly after the late 1970s from 4.38 to 4.75 petagram of carbon by 1998, for a mean accumulation rate of 0.021 petagram of carbon per year, mainly due to forest expansion and regrowth. Since the mid-1970s, planted forests (afforestation and reforestation) have sequestered 0.45 petagram of carbon, and their average carbon density increased from 15.3 to 31.1 megagrams per hectare, while natural forests have lost an additional 0.14 petagram of carbon, suggesting that carbon sequestration through forest management practices addressed in the Kyoto Protocol could help offset industrial carbon dioxide emissions.

Stimulation of new bone formation by direct transfer of osteogenic plasmid genes

Degradable matrices containing expression plasmid DNA [gene-activated matrices (GAMs)] were implanted into segmental gaps created in the adult rat femur. Implantation of GAMs containing beta-galactosidase or luciferase plasmids led to DNA uptake and functional enzyme expression by repair cells (granulation tissue) growing into the gap. Implantation of a GAM containing either a bone morphogenetic protein-4 plasmid or a plasmid coding for a fragment of parathyroid hormone (amino acids 1-34) resulted in a biological response of new bone filling the gap. Finally, implantation of a two-plasmid GAM encoding bone morphogenetic protein-4 and the parathyroid hormone fragment, which act synergistically in vitro, caused new bone to form faster than with either factor alone. These studies demonstrate for the first time that repair cells (fibroblasts) in bone can be genetically manipulated in vivo. While serving as a useful tool to study the biology of repair fibroblasts and the wound healing response, the GAM technology may also have wide therapeutic utility.

Variability of motor potentials evoked by transcranial magnetic stimulation

We studied the effect of stimulus intensity, coil size, mental alertness and prestimulus muscle contraction on the variability of motor evoked potentials (MEPs) produced by magnetic cortical stimulation (MCS). In 5 healthy subjects we delivered MCS either with a circular coil centered at the vertex or a figure-8 coil centered over the motor cortex hand area, recording from first dorsal interosseous. With the subject at rest or exerting 5% maximum voluntary contraction, 30 consecutive stimuli were given at 4 stimulus intensities (SIs) in 10% increments above resting motor threshold. Concurrent mental arithmetic constituted mental alertness. Spectral analysis was performed on data from 300 consecutive stimuli. The variability of MEP response size was inversely related to stimulus intensity, prestimulus voluntary muscle contraction, the recruitment of motoneurons and the size of the field generated by the magnetic coil. The MEP variability was larger than and not correlated with the variability of the H-reflex. Fast Fourier transformation and cross-correlation analysis did not identify a consistent dominant frequency, suggesting that the variability in MEP size is essentially random. We suggest that the variability in MEP response is caused by constant, rapid, spontaneous fluctuations in corticospinal and segmental motoneuron excitability levels. Any maneuver that raises this level or increases the probability of motoneuron firing will decrease MEP variability.

Effects of p21Waf1/Cip1/Sdi1 on cellular gene expression: implications for carcinogenesis, senescence, and age-related diseases

Induction of cyclin-dependent kinase inhibitor p21(Waf1/Cip1/Sdi1) triggers cell growth arrest associated with senescence and damage response. Overexpression of p21 from an inducible promoter in a human cell line induces growth arrest and phenotypic features of senescence. cDNA array hybridization showed that p21 expression selectively inhibits a set of genes involved in mitosis, DNA replication, segregation, and repair. The kinetics of inhibition of these genes on p21 induction parallels the onset of growth arrest, and their reexpression on release from p21 precedes the reentry of cells into cell cycle, indicating that inhibition of cell-cycle progression genes is a mechanism of p21-induced growth arrest. p21 also up-regulates multiple genes that have been associated with senescence or implicated in age-related diseases, including atherosclerosis, Alzheimer's disease, amyloidosis, and arthritis. Most of the tested p21-induced genes were not activated in cells that had been growth arrested by serum starvation, but some genes were induced in both forms of growth arrest. Several p21-induced genes encode secreted proteins with paracrine effects on cell growth and apoptosis. In agreement with the overexpression of such proteins, conditioned media from p21-induced cells were found to have antiapoptotic and mitogenic activity. These results suggest that the effects of p21 induction on gene expression in senescent cells may contribute to the pathogenesis of cancer and age-related diseases.

Amantadine as treatment for dyskinesias and motor fluctuations in Parkinson's disease

OBJECTIVE

To determine the effects of the N-methyl-D-aspartate (NMDA) antagonist amantadine on levodopa-associated dyskinesias and motor fluctuations in Parkinson's disease (PD).

BACKGROUND

NMDA receptor blockade can ameliorate levodopa-induced dyskinesias in primates and PD patients. Amantadine, a well-tolerated and modestly effective antiparkinsonian agent, was recently found to possess NMDA antagonistic properties.

METHODS

Eighteen patients with advanced PD participated in a double-blind, placebo-controlled, cross-over study. At the end of each 3-week treatment arm, parkinsonian and dyskinesia scores were obtained during a steady-state intravenous levodopa infusion. Motor fluctuations and dyskinesias were also documented with patient-kept diaries and Unified Parkinson's Disease Rating Scale (UPDRS) interviews.

RESULTS

In the 14 patients completing this trial, amantadine reduced dyskinesia severity by 60% (p = 0.001) compared to placebo, without altering the antiparkinsonian effect of levodopa. Motor fluctuations occurring with patients' regular oral levodopa regimen also improved according to UPDRS and patient-kept diaries.

CONCLUSIONS

These findings suggest that amantadine given as adjuvant to levodopa can markedly improve motor response complications and support the view that hyperfunction of NMDA receptors contributes to the pathogenesis of levodopa-associated motor complications.

Matrix metalloproteinase-2 is required for the switch to the angiogenic phenotype in a tumor model

Among the earliest and most important stages during tumorigenesis is the activation of the angiogenic process, an event that is termed the "switch to the angiogenic phenotype." We have developed an in vivo system that can reliably recapitulate the stages in tumor development that represent this transition. Using this model, we have harvested and studied tumor nodules that can be distinguished from each other on the basis of their degree of vascularization. Angiogenic tumor nodules were characterized by the presence of capillary vessels as determined by factor VIII immunohistochemistry, and both angiogenic and proteolytic activities in vitro. In contrast, preangiogenic nodules were devoid of microvessels and showed little angiogenic or proteolytic activity in vitro. Addition of a specific metalloproteinase inhibitor resulted in the abrogation of both angiogenic and proteolytic activities of the angiogenic nodules in vitro. Comparative substrate gel electrophoresis detected the presence of a prominent matrix metalloproteinase (MMP-2) in the angiogenic nodules when compared with the preangiogenic ones. Suppression of MMP-2 activity by antisense oligonucleotides in the vascular nodules resulted in the loss of angiogenic potential both in vitro and in vivo in the chick chorioallantoic membrane assay. Moreover, this suppression of MMP-2 activity in angiogenic nodules inhibited tumor growth in vivo by approximately 70%. These results strongly implicate the activity of MMP-2 as a requirement for the switch to the angiogenic phenotype and validate this model as a reliable and reproducible tool by which to study other cellular and biochemical factors involved in the acquisition of the angiogenic phenotype.

Role of p53 and p21waf1/cip1 in senescence-like terminal proliferation arrest induced in human tumor cells by chemotherapeutic drugs

Exposure of human tumor cell lines to moderate doses of anticancer agents induces terminal proliferation arrest accompanied by morphologic and enzymatic changes that resemble senescence of normal cells. We have investigated the role of p53 and p21waf1/cip1 in the induction of this response in drug-treated tumor cells. Doxorubicin treatment induced the senescence-like phenotype (SLP) and its associated terminal growth arrest in wild-type HCT116 colon carcinoma cells; this response was strongly decreased but not abolished in HCT116 lines with homozygous knockout of p53 or p21. Transduction of HT1080 fibrosarcoma cells with a genetic inhibitor of p53 also decreased the induction of SLP and increased drug-induced mitotic cell death. To determine if drug-stimulated p21 expression was responsible for senescence-like growth arrest, we have expressed different levels of p21 from an inducible promoter. While high-level overexpression of p21 was sufficient to induce SLP in HT1080 cells, the levels of p21 expressed in doxorubicin-treated cells could account for only a fraction of doxorubicin-induced SLP. Our results indicate that p53 and p21 act as positive regulators of senescence-like terminal proliferation arrest, but their function is neither sufficient nor absolutely required for this treatment response in tumor cells.

The role of cytokines in physiological sleep regulation

Several growth factors (GFs) are implicated in sleep regulation. It is posited that these GFs are produced in response to neural activity and affect input-output relationships within the neural circuits where they are produced, thereby inducing a local state shift. These GFs also influence synaptic efficacy. All the GFs currently identified as sleep regulatory substances are also implicated in synaptic plasticity. Among these substances, the most extensively studied for their role in sleep regulation are interleukin-1beta (IL-1) and tumor necrosis factor alpha (TNF). Injection of IL-1 or TNF enhances non-rapid eye movement sleep (NREMS). Inhibition of either IL-1 or TNF inhibits spontaneous sleep and the sleep rebound that occurs after sleep deprivation. Stimulation of the endogenous production of IL-1 and TNF enhances NREMS. Brain levels of IL-1 and TNF correlate with sleep propensity; for example, after sleep deprivation, their levels increase. IL-1 and TNF are part of a complex biochemical cascade regulating sleep. Downstream events include nitric oxide, growth hormone releasing hormone, nerve growth factor, nuclear factor kappa B, and possibly adenosine and prostaglandins. Endogenous substances moderating the effects of IL-1 and TNF include anti-inflammatory cytokines such as IL-4, IL-10, and IL-13. Clinical conditions altering IL-1 or TNF activity are associated with changes in sleep, for example, infectious disease and sleep apnea. As our knowledge of the biochemical regulation of sleep progresses, our understanding of sleep function and of many clinical conditions will improve.

Genomic and enzymatic evidence for acetogenesis among multiple lineages of the archaeal phylum Bathyarchaeota widespread in marine sediments

Members of the archaeal phylum Bathyarchaeota are widespread and abundant in the energy-deficient marine subsurface sediments. However, their life strategies have remained largely elusive. Here, we provide genetic evidence that some lineages of Bathyarchaeota are acetogens, being capable of homoacetogenesis, a metabolism so far restricted to the domain Bacteria. Metabolic reconstruction based on genomic bins assembled from the metagenome of deep-sea subsurface sediments shows that the metabolism of some lineages of Bathyarchaeota is similar to that of bona fide bacterial homoacetogens, by having pathways for acetogenesis and for the fermentative utilization of a variety of organic substrates. Heterologous expression and activity assay of the acetate kinase gene ack from Bathyarchaeota, demonstrate further the capability of these Bathyarchaeota to grow as acetogens. The presence and expression of bathyarchaeotal genes indicative of active acetogenesis was also confirmed in Peru Margin subsurface sediments where Bathyarchaeota are abundant. The analyses reveal that this ubiquitous and abundant subsurface archaeal group has adopted a versatile life strategy to make a living under energy-limiting conditions. These findings further expand the metabolic potential of Archaea and argue for a revision of the role of Archaea in the carbon cycle of marine sediments.

Metabolism of risperidone to 9-hydroxyrisperidone by human cytochromes P450 2D6 and 3A4

Risperidone is a relatively new antipsychotic drug that has been reported to improve both the positive and the negative symptoms of schizophrenia and produces relatively few extrapyramidal side effects at low doses. Formation of 9-hydroxyrisperidone, an active metabolite, is the most important metabolic pathway of risperidone in human. In the present study, in vitro metabolism of risperidone (100 microM) was investigated using the recombinant human cytochrome P450 (CYP) enzymes CYP1A1, CYP1A2, CYP2C8, CYP2C9-arg144, CYP2C9-cys144, CYP2C19, CYP2D6, CYP3A4 and CYP3A5 supplemented with an NADPH-generating system. 9-Hydroxyrisperidone was determined by a new HPLC method with an Hypersil CN column and a UV detector. Of these enzymes, CYPs 2D6, 3A4 and 3A5 were found to be the ones capable of metabolising risperidone to 9-hydroxyrisperidone, with activities of 7.5, 0.4 and 0.2 pmol pmol(-1) CYP min(-1), respectively. A correlation study using a panel of human liver microsomes showed that the formation of 9-hydroxyrisperidone is highly correlated with CYP2D6 and 3A activities. Thus, both CYP2D6 and 3A4 are involved in the 9-hydroxylation of risperidone at the concentration of risperidone used in this study. This observation is confirmed by the findings that both quinidine (inhibitor of CYP2D6) and ketoconazole (inhibitor of CYP3A4) can inhibit the formation of 9-hydroxyrisperidone. Furthermore, inducers of CYP can significantly increase the formation of 9-hydroxyrisperidone in rat. The formation of 9-hydroxyrisperidone is highly correlated with testosterone 6beta-hydroxylase activities, suggesting that inducible CYP3A contributes significantly to the metabolism of risperidone in rat.

Tumor-targeted induction of oxystress for cancer therapy

Reactive oxygen species (ROS), such as superoxide anion radicals (O.-2) and hydrogen peroxide (H2O2) are potentially harmful by-products of normal cellular metabolism that directly affect cellular functions. ROS is generated by all aerobic organisms and it seems to be indispensable for signal transduction pathways that regulate cell growth and reduction-oxidation (redox) status. However, overproduction of these highly reactive oxygen metabolites can initiate lethal chain reactions, which involve oxidation and damage to structures that are crucial for cellular integrity and survival. In fact, many antitumor agents, such as vinblastine, cisplatin, mitomycin C, doxorubicin, camptothecin, inostamycin, neocarzinostatin and many others exhibit antitumor activity via ROS-dependent activation of apoptotic cell death, suggesting potential use of ROS as an antitumor principle. Thus, a unique anticancer strategy named "oxidation therapy" has been developed by inducing cytotoxic oxystress for cancer treatment. This goal could be achieved mainly by two methods, namely, (i) inducing the generation of ROS directly to solid tumors and (ii) inhibiting the antioxidative enzyme (defense) system of tumor cells. Since 1950s, many strategies have been employed based on the first method, namely, administration of ROS per se (e.g. H2O2) or ROS generating enzyme to tumor bearing animals. However no successful and practical results were obtained probably because of the lack of tumor selective ROS delivery and hence resulting in subsequent induction of severe side effects. To overcome these obstacles, we developed polyethylene glycol (PEG) conjugated O.-2 or H2O2-generating enzymes, xanthine oxidase (XO) and D-amino acid oxidase (DAO) (PEG-DAO) respectively. More recently, a pegylated (PEG) zinc protoporphyrin (PEG-ZnPP) and a highly water soluble micellar formulation of ZnPP based on amphiphilic styrene maleic acid (SMA) copolymer, SMA-ZnPP, are prepared, which are potent inhibitors of heme oxygenase-1 (HO-1). HO-1 is a major antioxidative enzyme of tumors, that is different in mechanism of catalase or superoxide dismutase (SOD). Consequently, both PEG-enzymes and PEG-ZnPP exhibited superior in vivo pharmacokinetics than their parental molecules, particularly in tumor delivery by taking advantage of the EPR effect of macromolecular nature, and thus showed remarkable antitumor effects suggesting the potentials of this anticancer therapeutic for clinical application. Furthermore, it has been well known that many antioxidative enzymes such as catalase, SOD are down-regulated in most solid tumors in vivo. On the contrary, HO-1 is highly upregulated and it plays a very important role of antioxidation, because HO-1 generates biliverdin, which being converted to bilirubin exhibits a very potent antioxidative effect, and hence antiapoptosis in tumors. Thus this oxidation therapy, by inhibiting this HO-1 dependent antioxidant (bilirubin) formation by ZnPP, and by enhancing ROS generation, is expected to offer a powerful therapeutic modality for future anticancer therapy.

Amantadine for levodopa-induced dyskinesias: a 1-year follow-up study

BACKGROUND

In a recent acute study, amantadine was found to have antidyskinetic effect against levodopa-induced motor complications in patients with Parkinson disease. The longevity of this effect was not addressed but is of interest in light of the controversy in the literature regarding the duration of amantadine's well-established antiparkinsonian action.

OBJECTIVE

To determine the duration of the antidyskinetic effect of amantadine in advanced Parkinson disease.

DESIGN

One year after completion of an acute, double-blind, placebo-controlled, crossover study, patients returned for re-evaluation of motor symptoms and dyskinesias using a nonrandomized, double-blind, placebo-controlled follow-up paradigm.

SETTING

National Institutes of Health Clinical Center.

PATIENTS

Seventeen of the original 18 patients with advanced Parkinson disease complicated by dyskinesias and motor fluctuations participated in this study; 1 was lost to follow-up. Thirteen of the 17 individuals had remained on amantadine therapy for the entire year.

INTERVENTIONS

Ten days prior to the follow-up assessment, amantadine was replaced with identical capsules containing either amantadine or placebo.

MAIN OUTCOME MEASURES

Parkinsonian symptoms and dyskinesia severity were scored using standard rating scales, while subjects received steady-state intravenous levodopa infusions at the same rate as 1 year earlier.

RESULTS

One year after initiation of amantadine cotherapy, its antidyskinetic effect was similar in magnitude (56% reduction in dyskinesia compared with 60% 1 year earlier). Motor complications occurring with the patients' regular oral levodopa regimen also remained improved according to the Unified Parkinson's Disease Rating Scale (UPDRS-IV).

CONCLUSION

The beneficial effects of amantadine on motor response complications are maintained for at least 1 year after treatment initiation.

Antiapoptotic role of heme oxygenase (HO) and the potential of HO as a target in anticancer treatment

Heme oxygenase-1 (HO-1) is an inducible enzyme that catalyzes oxidative degradation of heme to form biliverdin, carbon monoxide (CO), and free iron. Biliverdin is subsequently reduced to bilirubin by the enzyme biliverdin reductase. Increasing evidence has indicated the critical role of HO-1 in cytoprotection and more diverse biological functions. Induction of HO-1 by various chemical inducers that are primarily cell stress inducers or by HO-1 gene transfection confers a protective capacity to cultured cells as well as to cells in several in vivo animal models. In addition, HO-1-deficient mice exhibit a significant increase in susceptibility to tissue injury. The cytoprotective action of HO-1 seems to be mainly a function of the antiapoptotic effects of the enzyme. HO-1 is believed to exert this antiapoptotic action by multiple mechanisms: (a) decreased intracellular pro-oxidant levels, (b) increased bilirubin levels, and (c) elevated CO production. CO may produce an antiapoptotic effect by inhibiting both expression of p53 and release of mitochondrial cytochrome c. HO-1 may also be a target in antitumor therapy because the growth of most tumors depends on HO-1. Our preliminary studies with an HO inhibitor showed a promising antitumor effect. This preliminary work warrants continued investigation for possible novel anticancer chemotherapy.

The association between birthplace and mortality from cardiovascular causes among black and white residents of New York City

BACKGROUND

Life expectancy is shorter and mortality from cardiovascular disease higher among blacks than among whites in the United States. We studied whether place of birth was associated with mortality from cardiovascular causes among non-Hispanic black and white residents of New York City.

METHODS

We linked mortality records from 1988 through 1992 with 1990 U.S. census data for New York City. Mortality data for blacks born in the U.S. South and Northeast and in the Caribbean were compared with those for whites born in the Northeast.

RESULTS

Among blacks, the rates of overall mortality and mortality from cardiovascular causes exceeded those among whites. Among persons born in the Northeast, the rates of death from cardiovascular disease for white men (285 per 100,000), as compared with black men (299), and for white women (155), as compared with black women (165), were similar. However, Southern-born black men and women both had mortality from cardiovascular disease that was substantially higher than that of their counterparts born in the Northeast, and Caribbean-born blacks had rates substantially lower than their Northeastern-born counterparts. The differences among the groups in the rates of death from coronary heart disease were greater than those for death due to stroke or hypertension. In each category defined by age and sex, Caribbean-born blacks had significantly lower rates of death from coronary heart disease than did whites. Black men who were 25 to 44 years of age and were born in the South had a rate of death from coronary heart disease that was 30 percent higher than that of Northeastern-born blacks, and four times that of Caribbean-born blacks of the same sex and age.

CONCLUSIONS

The higher rate of mortality from cardiovascular causes among blacks, as compared with whites, in New York City masks substantial variation among blacks based on their place of birth.

Structural and immunological studies of a major polysaccharide from spores of Ganoderma lucidum (Fr.) Karst

A polysaccharide isolated from spores of the fungus, Ganoderma lucidum, was found to be a complex glucan. On the basis of compositional and methylation analyses, periodate oxidation, Smith degradation, 1D and 2D NMR, and ESIMS experiments of the native polysaccharide and its degraded products, the polysaccharide was shown to have a backbone of beta-(1-->3)-linked D-glucopyranosyl residues, with branches of mono-, di- and oligosaccharide side chains substituting at the C-6 of the glucosyl residues in the main chain. Conformational analysis in aqueous solution and immunological activities of the native and degraded glucans were also investigated. The results suggested that the degree of substitution on the main chain and the length of side chains may be very important factors in determining the conformation and the biological activities of beta-(1-->3)-linked glucans.

Eosinophilic oesophagitis in patients presenting with dysphagia--a prospective analysis

BACKGROUND

Eosinophilic oesophagitis (EoO) may be a common finding in adults presenting with dysphagia.

AIM

To identify the risk factors and prevalence of EoO in an adult population with dysphagia.

METHODS

All patients with dysphagia referred for an upper endoscopy (EGD) were asked to participate. Patients completed a detailed questionnaire followed by EGD with four quadrant biopsies in the distal and mid-oesophagus. Primary endpoint was the prevalence of EoO; secondary endpoints included age, gender, asthma, food allergies, gastro-oesophageal reflux disease/dysphagia score and endoscopic findings.

RESULTS

Two hundred and sixty-one patients enrolled between December 2005 and January 2007. Thirty-one patients (12%) met pathological criteria for EoO. There was no difference in EoO prevalence within each gender. Mean age of EoO patients was 42 +/- 15 vs. 61 +/- 15 for non-EoO patients (P < 0.001). EoO was diagnosed in 35% of patients <50 years of age. EoO was present in 22% of asthmatics vs. 9% non-asthmatics (P < 0.01). EoO was present in 36.8% of patients with self-reported food allergies vs. 9.3% those without allergy (P < 0.001). A 13/31(42%) of EoO patients did not have the classic EGD findings (rings +/- furrows) and would have been missed without oesophageal biopsies.

CONCLUSIONS

Eosinophilic oesophagitis was diagnosed in 12% of the patients presenting with dysphagia with relative risk of 9.5 if age <50 years. Oesophageal biopsies are warranted in patients presenting with dysphagia especially in the younger population. Patients may not present with classic endoscopic findings and EoO can be missed without biopsies.

Molecular basis and characterization of the hyperinsulinism/hyperammonemia syndrome: predominance of mutations in exons 11 and 12 of the glutamate dehydrogenase gene. HI/HA Contributing Investigators

Glutamate dehydrogenase (GDH) is allosterically activated by the amino acid leucine to mediate protein stimulation of insulin secretion. Children with the hyperinsulinism/hyperammonemia (HI/HA) syndrome have symptomatic hypoglycemia plus persistent elevations of plasma ammonium. We have reported that HI/HA may be caused by dominant mutations of GDH that lie in a unique allosteric domain that is encoded within GDH exons 11 and 12. To examine the frequency of mutations in this domain, we screened genomic DNA from 48 unrelated cases with the HI/HA syndrome for exon 11 and 12 mutations in GDH. Twenty-five (52%) had mutations in these exons; 74% of the mutations were sporadic. Clinical manifestations included normal birth weight, late onset of hypoglycemia, diazoxide responsiveness, and protein-sensitive hypoglycemia. Enzymatic studies of lymphoblast GDH in seven of the mutations showed that all had reduced sensitivity to inhibition with GTP, consistent with an increase in enzyme activity. Mutations had little or no effect on enzyme responses to positive allosteric effectors, such as ADP or leucine. Based on the three-dimensional structure of GDH, the mutations may function by impairing the binding of an inhibitory GTP to a domain responsible for the allosteric and cooperativity properties of GDH.

Low levels of prostate-specific antigen predict long-term risk of prostate cancer: results from the Baltimore Longitudinal Study of Aging

OBJECTIVES

To evaluate the relationship between low prostate-specific antigen (PSA) levels that are considered normal and the long-term risk of prostate cancer.

METHODS

The relative risk of, and cumulative probability of freedom from, prostate cancer by PSA level and age decade was evaluated in male participants of a longitudinal aging study, the Baltimore Longitudinal Study of Aging (National Institute on Aging). The relative risk was estimated from a Cox proportional hazards regression model for men aged 40 to 49.9 (n = 351) and 50 to 59.9 (n = 445). The disease-free probability was determined by Kaplan-Meier survival analysis.

RESULTS

The relative risk of prostate cancer for men aged 40 to 49.9 was 3.75 (range 1.6 to 8.6) when the PSA level was at or greater than the median (0.60 ng/mL) compared with men with PSA levels less than the median. This risk was similar for men aged 50 to 59.9 when comparing those with PSA levels greater than and less than the median (0.71 ng/mL). At 25 years, the cumulative probability of freedom from prostate cancer for men aged 40 to 49.9 was 89.6% (range 81% to 97%) and 71.6% (range 60% to 83%) when the PSA level was less than and greater than the median, respectively. The 25-year disease-free probability for men aged 50 to 59.9 was 83.6% (range 76% to 91%) and 58.9% (range 48% to 70%) when the PSA level was less than and greater than the median, respectively.

CONCLUSIONS

The association between the baseline serum PSA level and the subsequent risk of prostate cancer suggests that the biologic events that predispose to prostate cancer begin early in middle age. Men who have baseline PSA levels that are "normal" but reflect a higher risk of prostate cancer may be the most appropriate candidates for future prevention trials. Those men with the lowest risk of prostate cancer on the basis of the baseline PSA measurements are unlikely to benefit from frequent PSA surveillance in an effort to detect prostate cancer early.

Structures of bovine glutamate dehydrogenase complexes elucidate the mechanism of purine regulation

Glutamate dehydrogenase is found in all organisms and catalyses the oxidative deamination of l-glutamate to 2-oxoglutarate. However, only animal GDH utilizes both NAD(H) or NADP(H) with comparable efficacy and exhibits a complex pattern of allosteric inhibition by a wide variety of small molecules. The major allosteric inhibitors are GTP and NADH and the two main allosteric activators are ADP and NAD(+). The structures presented here have refined and modified the previous structural model of allosteric regulation inferred from the original boGDH.NADH.GLU.GTP complex. The boGDH.NAD(+).alpha-KG complex structure clearly demonstrates that the second coenzyme-binding site lies directly under the "pivot helix" of the NAD(+) binding domain. In this complex, phosphates are observed to occupy the inhibitory GTP site and may be responsible for the previously observed structural stabilization by polyanions. The boGDH.NADPH.GLU.GTP complex shows the location of the additional phosphate on the active site coenzyme molecule and the GTP molecule bound to the GTP inhibitory site. As expected, since NADPH does not bind well to the second coenzyme site, no evidence of a bound molecule is observed at the second coenzyme site under the pivot helix. Therefore, these results suggest that the inhibitory GTP site is as previously identified. However, ADP, NAD(+), and NADH all bind under the pivot helix, but a second GTP molecule does not. Kinetic analysis of a hyperinsulinism/hyperammonemia mutant strongly suggests that ATP can inhibit the reaction by binding to the GTP site. Finally, the fact that NADH, NAD(+), and ADP all bind to the same site requires a re-analysis of the previous models for NADH inhibition.

Antiapoptotic effect of haem oxygenase-1 induced by nitric oxide in experimental solid tumour

Induction of haem oxygenase-1 (HO-1) may provide an important protective effect for cells against oxidative stress. Here, we investigated the mechanism of cytoprotection of HO-1 in solid tumour with a focus on the antiapoptotic activity of HO-1. Treatment of rat hepatoma AH136B cells with the HO inhibitor zinc protoporphyrin IX (ZnPP IX) or tin protoporphyrin IX resulted in extensive apoptotic changes of tumour cells both in vivo and in vitro. Caspase-3 activity of the ZnPP IX-treated hepatoma cells increased significantly. Moreover, ZnPP IX-induced apoptosis was completely inhibited by simultaneous incubation with a specific caspase-3 inhibitor and was partially abrogated by bilirubin, a reaction product of HO. In vivo ZnPP IX treatment did not affect nitric oxide (NO) production and tumour blood flow. Western blot analyses showed that HO-1 expression in AH136B cells was strongly upregulated by NO donors, for example, S-nitroso-N-acetyl penicillamine and propylamine NONOate in vitro; conversely, it was remarkably reduced in vivo by pharmacological blockade of NOS. We conclude that HO-1 may function in antiapoptotic defense of the tumour, and thus it may have important protective and beneficial effects for tumour cells against oxidative stress induced by NO, which is produced in excess during solid tumour growth in vivo.

p21Waf1/Cip1/Sdi1-induced growth arrest is associated with depletion of mitosis-control proteins and leads to abnormal mitosis and endoreduplication in recovering cells

Induction of a cyclin-dependent kinase inhibitor p21Waf1/ Cip1/Sdi1 is an integral part of cell growth arrest associated with senescence and damage response. p21 overexpression from an inducible promoter resulted in senescence-like growth arrest in a human fibrosarcoma cell line. After release from p21-induced growth arrest, cells re-entered the cell cycle but displayed growth retardation, cell death and decreased clonogenicity. The failure to form colonies was associated with abnormal mitosis and endoreduplication in the recovering cells and was correlated with the induced level of p21 and the duration of p21 induction. p21 induction was found to inhibit the expression of multiple proteins involved in the execution and control of mitosis. p21-induced depletion of the cellular pools of mitosis-control proteins was followed by asynchronous resynthesis of such proteins after release from p21, which explains the observed mitotic abnormalities. Genetic destabilization in cells recovering from p21-induced growth arrest may conceivably play a role in carcinogenesis and tumor progression.

Clinical characteristics of non-critically ill patients with novel coronavirus infection (COVID-19) in a Fangcang Hospital

OBJECTIVES

To describe the clinical characteristics of patients in a Fangcang Hospital.

METHODS

Non-critically ill individuals with positive SARS-CoV-2 RT-PCR tests admitted between 7 February and 12 February 2020 to Dongxihu Fangcang Hospital, which was promptly constructed because of the rapid, exponential increase in COVID-19 patients in Wuhan, China, were included; clinical course through to 22 February was recorded.

RESULTS

A total of 1012 non-critically ill individuals with positive SARS-CoV-2 RT-PCR tests were included in the study. Thirty (of 1012, 3.0%) individuals were asymptomatic on admission. During hospitalization, 16 of 30 (53.3%) asymptomatic individuals developed different symptoms. Fourteen of 1012 patients (1.4%) remained asymptomatic from exposure to the end of follow up, with a median duration of 24 days (interquartile range 22-27). Fever (761 of 1012, 75.2%) and cough (531 of 1012, 52.4%) were the most common symptoms. Small patchy opacities (355 of 917, 38.7%) and ground-glass opacities (508 of 917, 55.4%) were common imaging manifestations in chest CT scans. One hundred patients (9.9%) were transferred to designated hospitals due to aggravation of illness. Diarrhoea emerged in 152 of 1012 patients (15.0%). Male, older age, diabetes, cardiovascular diseases, chills, dyspnoea, So2 value of ≤93%, white blood cell counts of >10 × 109/L and large consolidated opacities on CT images were all risk factors for aggravation of illness.

CONCLUSIONS

Non-critically ill individuals had different clinical characteristics from critically ill individuals. Asymptomatic infections only accounted for a small proportion of COVID-19. Although with a low incidence, diarrhoea was observed in patients with COVID-19, indicating the possibility of faecal-oral transmission.