Leptin resistance is associated with extreme obesity and aggregates in families

OBJECTIVE

To examine the determinants of plasma leptin levels and leptin resistance in a sample of extremely obese subjects and their relatives.

DESIGN AND METHOD

We obtained plasma leptin values on 968 individuals from 218 families having both extremely obese and average weight members for obesity related variables. Multivariate regression analyses were used to identify predictors of both plasma leptin concentration and an index of leptin resistance. Family correlations and heritabilities were computed for plasma leptin and indices of leptin resistance.

RESULTS

Body mass index and sex predicted 63% of the variance in plasma leptin. Extremely obese subjects were most likely and average weight subjects least likely to be leptin resistant. Both leptin and leptin resistance aggregated within families.

CONCLUSION

Leptin resistance is strongly associated with extreme obesity and appears to be a heritable trait. The determination of its genetic causes will aid in understanding the role of leptin in common forms of human obesity.

Characterization of mutations, including a novel regulatory defect in the first intron, in Bruton's tyrosine kinase gene from seven Korean X-linked agammaglobulinemia families

In this report, we describe seven mutations, including a novel single base pair substitution in intron 1, of the Bruton's tyrosine kinase (Btk) gene found in 12 Korean patients with X-linked agammaglobulinemia. Various mutations, including three novel genetic alterations, were discovered using single-strand conformation polymorphism analysis and direct DNA sequencing. The effect of the intron 1 point mutation (intron 1 +5G-->A) was further evaluated using reporter constructs. Using luciferase assay experiments, we showed that the transcriptional activity of the mutant was significantly lower than in normal counterparts, indicating that the intronic mutation was functional. In addition, DNase I footprinting analysis showed that a single protected region spanning the position +3 to +15 bp hybridized with a mutant-specific probe, but not with a wild-type probe. EMSA indicated that a distinct nuclear protein has the ability to bind the mutant oligonucleotides to produce a new DNA-protein complex. We also observed decreased expression of Btk proteins in monocytes of patients having the point mutation in intron 1. Taken together with the functional analysis, our results strongly suggest the existence of a novel cis-acting element, which might be involved in the down-regulation of Btk gene transcription. Precise definition of the regulatory defect in the Btk intron 1 may provide valuable clues toward elucidating the pathogenesis of X-linked agammaglobulinemia.

Pathogenic role of endothelin 1 in hemodynamic dysfunction in experimental acute pulmonary thromboembolism

The plasma endothelin-1 (ET-1) level is elevated in patients with acute pulmonary thromboembolism (APE). Whether ET-1 is a pathogenic mediator or a simple marker of APE is not known. We investigated the role of ET-1 in hemodynamic dysfunction in APE through evaluating the effects of ET(A) receptor antagonist in an experimental APE model. We also examined ET-1 expression in embolized lungs. In a canine autologous blood clot pulmonary embolism model, ET(A) receptor antagonist ZD2574 (10 mg/kg, intravenous; ZD2574 group; n = 6) or vehicle (control group; n = 5) was administered. Hemodynamic and gas exchange parameters and plasma levels of ET-1 were serially measured. Prepro-ET-1 mRNA expression and the distribution of ET-1 peptide in lung tissues were also examined. With ZD2574 pulmonary arterial pressure and pulmonary vascular resistance significantly decreased, and were lower compared with the control group. The decrease in cardiac output was also less in the ZD2574 group. Plasma ET-1 levels increased after embolization. Prepro-ET-1 mRNA expression increased in embolized lungs and ET-1 peptide expression also increased in embolized lungs, particularly in the muscular pulmonary arteries, compared with normal lungs. These findings suggest that ET-1 partially contributes to hemodynamic derangements of APE, and that ET(A) receptor antagonists might constitute a useful therapeutic tool for APE.

Chiral separation of beta-blockers after derivatization with (-)-alphamethoxy-alpha-(trifluoromethyl)phenylacetyl chloride by gas chromatography

Gas chromatographic method was investigated for the chiral separation of several beta-blockers(atenolol, betaxolol, bisoprolol, metoprolol and pindolol) using (-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride as a chiral derivatizing agent for amino group. Prior to N-acylation, hydroxyl group was converted into O-silyl ethers by react with N-methyl-N-(trimethylsilyl)trifluoroacetamide. The reaction was selective and rapid and the diastereomeric derivatives were well separated by capillary gas chromatography. (R)-isomers were eluted faster than (S)-isomers when (-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride was used as the chiral derivatizing agent. But in the opposite sequence when (+)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride was used. No racemization was found during the reaction.

Correlation of plasma homocysteine and mitochondrial DNA content in peripheral blood in healthy women

Hyperhomocysteinemia is an independent risk factor of cardiovascular disease and associated with insulin resistance, although their causal relationship remains unclear. A previous report has shown that high concentration of homocysteine damages mitochondrial gene expression, function and structure. As we found recently, the mitochondrial DNA (mtDNA) contents are inversely correlated with insulin resistance parameters. Thus there is possibility that plasma total homocysteine (tHcy) level is somewhat correlated with mtDNA content. Sixty healthy women (mean age 40.3+/-20.9 yr, range 18-78 yr) were recruited to investigate the correlation of plasma tHcy level and mtDNA content in peripheral blood. A significant negative correlation was found between plasma tHcy levels and mtDNA content (r=-0.507, P<0.01). Plasma tHcy and mtDNA content have an independent effect on each other and on insulin resistance (HOMA-insulin resistance (IR) score) respectively in multiple regression model. Plasma tHcy showed positive correlations with age (r=0.407), W/H ratio (r=0.370), total cholesterol (r=0.338), LDL-cholesterol (r=0.317) and insulin resistance (HOMA-IR score) (r=0.261); and a negative correlation with folate (r=-0.273). MtDNA content showed negative correlations with age (r=-0.407), BMI (r=-0.440), W/H ratio (r=-0.659), SBP (r=-0.350), total cholesterol (r=-0.340), triglyceride (r=-0.376), LDL-cholesterol (r=-0.349), fasting plasma insulin (r=-0.483), and insulin resistance (HOMA-IR score) (r=-0.423); and a positive correlation with folate (r=0.299). In this study, there was a significant inverse correlation between plasma tHcy level and mtDNA content. Further study will be warranted to elucidate the mechanism by which two factors are associated.

Mortality and apolipoprotein E in Hispanic, African-American, and Caucasian elders

To investigate whether mortality risk is influenced by apolipoprotein E (APOE) genotype and whether the risk differs by ethnicity, we compared the mortality risk in 2,112 individuals > or = 65 years of age residing in northern Manhattan in New York. Mortality risks associated with the APOE genotype, adjusted for sex, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides, differed significantly by ethnic group. Among Caucasian and Hispanics, the E2/E3 genotype was associated with the lowest mortality risk in the multivariate Cox proportional hazards modeling, adjusted for lipid levels, whereas mortality risk did not differ substantially between the E4/E3 and E3/E3 genotypes. Among African-Americans, the E2/E3 genotype was not associated with the lowest mortality risk, but the E4/E3 genotype was. Adjustment for heart disease, diabetes, and stroke reduced mortality risk associated with each genotype by about 50% for all ethnic groups, but the patterns remained the same. Although we cannot rule out the possibility of a healthy survival bias, our analyses designed to examine healthy survival by comparing risk of mortality in groups who were younger or older at entry do not support this possibility. Our findings suggest that the APOE genotype is associated with mortality and that the genotypic risks differ by ethnic group. Nearly 50% of the mortality risk associated with the APOE genotype appears to act through major chronic diseases, but those diseases only partially explain the mechanism by which the genotypic risk acts. To better understand the observed ethnic differences in mortality risk by genotype, a detailed prospective study is needed to examine the relationships among APOE, other candidate genes, health conditions, and eventual death.

Age-related increase of brain cyclooxygenase activity and dietary modulation of oxidative status

Several studies have demonstrated that inhibitors of cyclooxygenase (COX) attenuate various neuronal injuries and age-dependent demented conditions. From these findings, we proposed to test the effect of age on COX activity and its possible suppression by the antiaging action of dietary restriction in the rat brain. The status of reactive oxygen species (ROS) was also assessed to correlate with COX activity to delineate the underlying mechanism of the altered COX activity during aging. These results showed that COX activity significantly increased in 24-month-old rats compared with 6-month-old rats in an ad libitum group. Interestingly, mRNA and protein levels of COX-2 showed little corresponding age-related change. The formation of ROS was found to increase gradually with age in ad libitum fed rats. However, dietary restriction suppressed the increase at the age of 24 months. To substantiate the relationship between ROS and COX activity when the rats were 24 months of age, we conducted in vitro experiments with a C6 glioma cell line. Together, it is concluded that increased COX activity with age is due to the activation of COX catalytic reaction by ROS without increased gene expression of COX-2 and that it is related to the increased pro-oxidant status in aged rats.

Combination Chemotherapy of Oxaliplatin, 5-Fluorouracil, and Leucovorin in 5-Fluorouracil-Pretreated Patients with Metastatic Colorectal Cancer

PURPOSE

To evaluate the efficacy and toxicity of oxaliplatin in combination with 5-fluorouracil (5-FU) and leucovorin (LV) in patients with metastatic colorectal cancer who previously treated with 5-FU-based chemotherapy.

MATERIALS AND METHODS

Between April 1999 and January 2001, thirty-two patients were enrolled in this study. Oxaliplatin 130 mg/m2 was given intravenously (IV) on day 1 as was 5-FU 500 mg/m2 IV followed by continuous infusion of 5-FU 3,000 mg/m2 and LV 100 mg/m2 for 48 hours administered every 3 weeks. Six patients had received 5-FU as an adjuvant setting and 26 patients as a palliative regimen.

RESULTS

The median age of the patients was 50 years (range; 19-69) and the dominant sites of metastasis were the liver, lung or both in 9, 5 and 2 patients respectively. In 30 evaluable patients, the overall response rate was 27% including 1 complete response and 7 partial responses. The median response duration was 28 weeks (95% confidence interval; 22~34 weeks) and the median progression free survival of all patients was 24 weeks (95% confidence interval; 15~33 weeks). A median 5 cycles (range; 2~9) and total 155 cycles were performed in 32 patients. 150 cycles were evaluable for toxicity. The most common hematologic toxicity was grade 1~2 anemia in 78 cycles (52%). Leukopenia (39%) and thrombocytopenia (23%) were fully reversible. The most common non-hematologic toxicity was nausea/vomiting (43/30%) followed by diarrhea (23%), hepatotoxicity (21%) and neurotoxicity (21%). One patient ceased therapy due to grade 4 diarrhea. No other severe toxicity interrupted this treatment.

CONCLUSION

Oxaliplatin, 5-FU and LV in combination showed significant activity in previously treated metastatic colorectal cancer with favorable toxicity.

Cervicofacial rhytidectomy after head and neck tumor removal

OBJECTIVE

To compare intraoperative and postoperative complication rates of cervicofacial rhytidectomy after head and neck tumor removal with complication rates of rhytidectomy in the normal patient population.

STUDY DESIGN

Retrospective chart review and literature review.

METHODS

A sample of 11 patients treated by a single surgeon (D.A.S.) at an academic referral center who met the inclusion criteria was reviewed for previous head and neck surgical history, medical history, and surgical results and subsequent complications of the facial esthetic procedure. These rates were compared with the complication rates for cervicofacial rhytidectomy in normal patients as quoted in the general medical literature.

RESULTS

Patients ranged in age from 48 to 75 years (mean age, 58 y). Of the 11, no patient experienced a major complication of rhytidectomy, and two experienced a minor postoperative complication. Both patients had received postoperative radiation for the treatment of their previous tumor, and both noted a small (<1.5 cm) area of wound dehiscence before postoperative day 10, which required no revision and healed without sequelae. No other intraoperative or postoperative complications were found.

CONCLUSION

Cervicofacial rhytidectomy may be safely and effectively performed on postoperative patients with head and neck tumors without increased incidence of major complications when compared with patients without a surgical tumor history. The increased incidence of minor wound dehiscence experienced by 2 of the 3 patients who received postoperative radiation in this study may indicate that small areas of skin incision dehiscence are more likely in patients who have been radiated. Surgeons performing rhytidectomy on patients with head and neck tumors who were previously radiated should consider more meticulous subdermal closure to avoid such dehiscence. Patients should be informed of the slightly higher risk of dehiscence before surgery.

A large-scale purification of recombinant histone H1.5 from Escherichia coli

An Escherichia coli expression system has been constructed for production of biologically active recombinant histone H1.5. A process of fermentation and purification method at a large scale has been developed. Recombinant histone H1.5 was released from the high density cultured cells by high-pressure homogenization. For an efficient removal of cell debris and partial purification of basic histone H1.5 in a single step, the whole cell lysates were directly loaded onto an expanded bed column packed with the strong cation exchanger (Streamline SP). Complete removal of various impurities was achieved by a combination of hydroxyapatite chromatography and the following cation exchange chromatography with high grade strong cation exchanger (POROS 20 HS), and finally endotoxins were removed by ultrafiltration using a 100-kDa cut-off membrane, which gave the level of endotoxin below 0.5 EU/mg. The molecular mass of the recombinant histone H1.5 analyzed by MALDI-TOF-MS, and the N-terminal amino acid sequences were in good agreement with the authentic histone H1.5. The whole process gave highly purified recombinant histone H1.5 at a high yield, compared to the conventional process.

Fas mediates apoptosis in steroid-induced myopathy of rats

Recently, apoptotic cell death has been reported in differentiated skeletal muscle, where apoptosis was generally assumed not to occur. To investigate whether apoptosis may contribute to the steroid-induced myopathy, rats treated with triamcinolone acetonide (TA) for 9 days were sacrificed for detecting apoptosis by in situ end-labelling (ISEL) and DNA electrophoresis in soleus muscles. Immunohistochemical stainings of Fas antigen and p53 protein were performed to examine whether apoptosis-related proteins were present in the myopathy. Muscle fibre necrosis and apoptotic myonuclei appeared in soleus muscles following administration of TA, while control muscles showed no evidences for apoptosis. Fas antigen was not detected in control muscles, but expressed in soleus muscles of steroid-induced myopathy. Some of the Fas antigen-expressing muscle fibres were positive for ISEL. p53 Protein was not detected in any muscle fibres. These findings indicate that TA can induce apoptosis in differentiated skeletal muscles, and Fas antigen might be partly related to apoptotic muscle death in steroid-induced myopathy.

Do high glucose levels have differential effect on FDG uptake in inflammatory and malignant disorders?

BACKGROUND

The association of hyperglycaemia with reduced fluorodeoxyglucose (FDG) uptake by tumour cells is well established. Therefore, it is standard practice that all patients must fast for at least several hours prior to FDG positron emission tomography (PET) imaging. However, the effect of hyperglycaemia on FDG uptake by inflammatory and infectious lesions is unknown. The aim of this study was to investigate this important issue.

METHODS

For in vitro studies human mononuclear cells were isolated from 12 normal volunteers and FDG uptake was determined in medium containing differing concentrations of glucose. FDG uptake by human mesothelioma cells was also measured for comparison. For studies involving patients, 416 FDG PET scans of patients with confirmed malignancy (n=321) or benign lesions (n=95) were reviewed retrospectively. The relationship between serum glucose level and FDG uptake by the lesions was assessed utilizing the standardized uptake value (SUV) technique.

RESULTS

In the in vitro studies, while FDG uptake by mesothelioma cells decreased as glucose concentration increased, there was no differential uptake of FDG uptake by mononuclear cells at glucose concentrations less than 250 mg x dl(-1). In clinical patients, FDG uptake by malignant lesions was slightly, but negatively affected by serum glucose level (r= -0.21, P<0.01) (glucose range 49-187 mg x dl(-1)). In contrast, FDG uptake by inflammatory lesions was positively associated with serum glucose level (r=0.43, P<0.01) (glucose range 54-215 mg x dl(-1)).

DISCUSSION AND CONCLUSION

While the degree of FDG uptake is primarily influenced by the nature of the underlying lesion, serum glucose concentration appears to have a small effect on FDG uptake, which differs between malignant disorders and inflammatory processes. Our data suggest that below a certain level, elevated glucose concentration might not have a negative effect on FDG uptake in inflammatory cells, contrary to that observed in malignant disorders.

Interleukin-13 induces dramatically different transcriptional programs in three human airway cell types

Interleukin (IL)-13, a cytokine released by T lymphocytes during immediate hypersensitivity responses, is a central mediator of asthma. Because IL-13 induces phenotypic features of asthma in mice deficient in T and B lymphocytes, it is likely that this cytokine contributes to the development of asthma by acting directly on resident airway cells. To analyze the global effects of IL-13 on gene expression in airway cells that could contribute to the phenotypic features of asthma, we used Genechip HuGene FL arrays (Affymetrix, Santa Clara, CA) that contain probes for approximately 6,500 human genes. Despite activating a common signaling pathway, IL-13 induced dramatically different patterns of gene expression in primary cultures of airway epithelial cells, airway smooth muscle cells, and lung fibroblasts, with little overlap among cell types. The most prominent effects of IL-13 were on airway smooth muscle, but several genes induced in airway epithelial cells and fibroblasts are also candidates that may contribute to phenotypic features of asthma. These results suggest that the in vivo response to IL-13 in the airways likely results from a combination of distinct effects on each of several resident airway cell types.

Molecular identification of Oxalobacter formigenes with the polymerase chain reaction in fresh or frozen fecal samples

OBJECTIVE

To develop a simple and rapid polymerase chain reaction (PCR) method for detecting Oxalobacter formigenes (which degrades oxalate in the gut) in fecal specimens from healthy volunteers and patients with urolithiasis, and to determine whether O. formigenes can be detected in frozen or fresh fecal samples.

MATERIALS AND METHODS

Whole bacterial DNA was isolated directly from fresh and frozen fecal samples obtained from 30 healthy volunteers free from urolithiasis and from fresh fecal samples obtained from 38 patients with urolithiasis. Genus-specific oligonucleotide sequences were designed, corresponding to homologous regions residing in the oxc gene that encodes for oxalyl-coenzyme A decarboxylase. A PCR-based assay was used on both fresh and frozen fecal samples, and the nucleotide sequences analysed to confirm oxc.

RESULTS

A PCR product of 416 bp encoding the oxc gene was detected in 23 (77%) of 30 healthy volunteers free from urolithiasis and in 14 (37%) of 38 patients with urolithiasis. In healthy volunteers, the results of PCR for the fresh and the frozen samples were identical in each subject. The nucleotide sequence analysis showed that the sequence of the amplified product was compatible with that of oxc.

CONCLUSION

O. formigenes can be identified easily and efficiently using this PCR-based detection system. The colonization rate of O. formigenes in patients with urolithiasis was significantly lower than that in healthy volunteers known to be free from urolithiasis. Furthermore, as the PCR-based assay results in the frozen fecal samples were identical to those from fresh samples in each subject, immediate processing of fecal samples may not be necessary to detect O. formigenes in the clinical setting.

Epidemiologic and clinical survey of Behcet's disease in Korea: the first multicenter study

The prevalence of Behcet's disease is the highest in the East Asian and the Mediterranean countries. Behcet's disease is also distributed in the Asian countries, but the nationwide survey has not been performed in Korea yet. The Korean Study Group for Behcet's Disease, founded in 1999, conducted a multicenter, retrospective survey on epidemiologic and clinical features of the patients with Behcet's disease from 20 hospitals around the nation from 1997 to 1999. Of 3,497 patients, 1,527 were classified into complete or incomplete type of Behcet's disease according to the revised Shimizu's classification. The sex ratio was 1:1.75 with the female predominance. Geographical distribution showed the highest frequency in Seoul (38.5%). Clinically, 98.8% had oral ulcers, 83.2% had genital ulcers, 84.3% had skin lesions and 50.9% had ocular lesions. As for the minor clinical manifestations, articular symptoms were the most frequent. The pathergy test showed positive in 15.4% of patients and revealed a higher positive rate in males (20.2%) than in females (12.7%). In conclusion, we performed the first multicenter study on Behcet's disease in Korea and revealed the female predominance, higher frequency of ocular lesions, and lower positivity of pathergy test in the patients.

Anti-angiogenic activities of gliotoxin and its methylthioderivative, fungal metabolites

In the search for new naturally occurring angiogenic inhibitor, we found that culture broths from two unidentified fungal strains exerted potent inhibitory activities on capillary-like tube formation of human umbilical vein endothelial cells (HUVEC) in vitro. Two active compounds were isolated by bioassay-guided separation and their structures were identified as gliotoxin (1) and its derivative methylthiogliotoxin (2) by spectroscopic analyses. These compounds significantly inhibited the migration of HUVEC assessed by in vitro wounding migration assay and exhibited at least 10 times more potent inhibition of proliferation of HUVECs as compared with that of cancer cell lines such as HeLa, MCF-7, and KB 3-1 cells. Especially, gliotoxin having disulfide group exerted more potent activities than methylthiogliotoxin, suggesting that gliotoxin could be a useful compound for further study as an anti-angiogenic agent.

Risk of death from intercurrent disease is not excessively increased by modern postoperative radiotherapy for high-risk resected non-small-cell lung carcinoma

PURPOSE

Some studies report a high risk of death from intercurrent disease (DID) after postoperative radiotherapy (XRT) for non-small-cell lung cancer (NSCLC). This study determines the risk of DID after modern-technique postoperative XRT.

PATIENTS AND METHODS

A total of 202 patients were treated with surgery and postoperative XRT for NSCLC. Most patients (97%) had pathologic stage II or III disease. Many patients (41%) had positive/close/uncertain resection margins. The median XRT dose was 55 Gy with fraction size of 1.8 to 2 Gy. The risk of DID was calculated actuarially and included patients who died of unknown/uncertain causes. Median follow-up was 24 months for all patients and 62 months for survivors.

RESULTS

A total of 25 patients (12.5%) died from intercurrent disease, 16 from confirmed noncancer causes and nine from unknown causes. The 4-year actuarial rate of DID was 13.5%. This is minimally increased compared with the expected rate for a matched population (approximately 10% at 4 years). On multivariate analysis, age and radiotherapy dose were borderline significant factors associated with a higher risk of DID (P =.06). The crude risk of DID for patients receiving less than 54 Gy was 2% (4-year actuarial risk 0%) versus 17% for XRT dose > or = 54 Gy. The 4-year actuarial overall survival was 34%; local control was 84%; and freedom from distant metastases was 37%.

CONCLUSION

Modern postoperative XRT for NSCLC does not excessively increase the risk of intercurrent deaths. Further study of postoperative XRT, particularly when using more sophisticated treatment planning and reasonable total doses, for carefully selected high-risk resected NSCLC is warranted.

Comparative porcine gene mapping relative to human chromosomes 9, 10, 20 and 22

Comparative anchor tagged sequence (CATS) consensus primers from loci mapped to human chromosomes 9, 10, 20, and 22 have been used to amplify homologous loci in pigs. Of 53, CATS primers tested in pigs, only 23 yielded products homologous to the human locus (42% success). Ten loci were physically mapped (43% success rate for verified products, but only 19% for primers tested). Due to lack of polymorphism, linkage mapping was possible only for AMBP. Map locations were consistent with human/pig ZOO-FISH, except for ADRA1A, whose position is still equivocal in humans. These CATS primers have made very limited contributions to pig/human comparative gene mapping because of low efficiency of amplification of orthologous porcine product, frequent amplification from rodent template in a somatic hybrid panel and low level of polymorphism.

Development of a packaging cell line for propagation of replication-deficient adenovirus vector

A human embryonic kidney cell line 293 is widely used for adenovirus production and propagation. With this cell line, however, replication-competent virus (RCV) is frequently generated, especially during large-scale production and successive propagation because 293 cells contain not only E1 gene but also non-E1 adenovirus gene. Homologous recombination between non-E1 region of 293 genomic DNA and its homologous region in the recombinant adenoviral vector generate RCV. To overcome this problem, we developed a new packaging cell line, Hela-E1, which contains minimum E1 region and from which non-E1 adenoviral region that is homologous with recombinant adenovirus vector was excluded. No RCV was detected during adenovirus propagation in Hela-E1 compared to in 293. In addition, adenovirus-p53 produced in HeLa-E1 was able to overexpress p53 protein when introduced into an ovarian cancer cell line, SKOV3. These results may have a significant impact on the development of packaging cell lines for replication-deficient adenovirus production.

Specificity of the fivefold increase in AD in mothers of adults with Down syndrome

BACKGROUND

In a previous study, the authors found that the risk of AD among mothers who were 35 years or younger when their children with Down syndrome (DS) were born was five times that of mothers of children with other forms of mental retardation. The current study investigated the specificity of the familial aggregation of DS and AD by examining whether mothers who gave birth to children with DS before age 35 are also at increased risk of other age-related neurologic or medical disorders.

METHODS

The authors used survival methods to compare cumulative incidence and relative risk of AD, other dementias, and common age-related disorders in parents of 200 adults with DS and parents of 252 adults with other forms of mental retardation.

RESULTS

Mothers who were < or =35 years of age when their children with DS were born were four to five times as likely to develop AD as control mothers (rate ratio = 4.8, 95% CI 2.1, 11.2), whereas risk of AD among mothers who were >35 years when their children with DS were born was not significantly increased (rate ratio = 1.8, 95% CI 0.6, 5.1). Risk of AD among fathers of probands with DS was similar to that of control fathers, and did not vary by age at proband birth. Risk of other dementias and of other age-related medical condition was similar among mothers and fathers of probands with DS and control parents, regardless of age at proband birth.

CONCLUSION

These findings suggest that the increased risk of AD among mothers who gave birth to children with DS before age 35 appears to represent a specific vulnerability to AD, as opposed to other age-related degenerative disorders.

Effects of clozapine on sleep measures and sleep-associated changes in growth hormone and cortisol in patients with schizophrenia

There have been limited reports on the effect of the atypical anti-psychotic agent clozapine on sleep measures and hormone secretion. The goal of this study was to determine the type, rate, and extent of changes in sleep measures and nighttime secretion of growth hormone (GH) and cortisol during clozapine treatment. Five schizophrenic patients (age: 32.4+/-7.4) and five age- and sex-matched normal subjects (age: 33.0+/-5.1) underwent nocturnal polysomnography (NPSG) before clozapine therapy (S1), and during early and late clozapine therapy (S2 and S3). Serum GH and cortisol levels were monitored during each NPSG. NPSG findings showed that the mean total sleep time, sleep efficiency, and duration of awakening were increased at S2, and maintained until S3. The mean amounts of stage 2 sleep at S2 and S3 increased significantly compared with that of S1. In unmedicated schizophrenic patients, the mean plasma GH level in rapid eye movement sleep was lower than during the waking stage, and the mean level of plasma cortisol was higher during the waking stage. Plasma cortisol levels did not differ between control subjects and patients at any time, but clozapine treatment decreased plasma cortisol levels at S2 compared with S1 and S3. Plasma GH levels were unchanged by clozapine treatment. Clozapine improved sleep continuity and increased stage 2 sleep time from the beginning of therapy. These effects were maintained through at least 7 weeks of therapy. However, clozapine did not affect the relationship of plasma GH and cortisol levels with sleep stages in schizophrenic patients.

Phosphorylation of the leucocyte NADPH oxidase subunit p47(phox) by casein kinase 2: conformation-dependent phosphorylation and modulation of oxidase activity

The leucocyte NADPH oxidase of neutrophils is a membrane-bound enzyme that catalyses the reduction of oxygen to O(-)(2) at the expense of NADPH. The enzyme is dormant in resting neutrophils but becomes active when the cells are exposed to the appropriate stimuli. During oxidase activation, the highly basic cytosolic oxidase component p47(phox) becomes phosphorylated on several serines and migrates to the plasma membrane. Protein kinase CK2 is an essential serine/threonine kinase present in all eukaryotic organisms. The leucocyte NADPH oxidase subunit p47(phox) has several putative CK2 phosphorylation sites. In the present study, we report that CK2 is able to catalyse the phosphorylation of p47(phox) in vitro. Phosphoamino acid analysis of phosphorylated p47(phox) by CK2 indicated that the phosphorylation occurs on serine residues. CNBr mapping and phosphorylation of peptides containing the putative site of CK2 indicated that the main phosphorylated residues are Ser-208 and Ser-283 in the Src homology 3 (SH3) domains, and Ser-348 in the C-terminal domain of p47(phox). Dependence of phosphorylation on the conformation of p47(phox) is supported by the finding that p47(phox) undergoes better phosphorylation by CK2 in the presence of arachidonic acid, a known activator of NADPH oxidase which induces conformational changes in p47(phox). In addition, 5,6-dichloro-1-beta-o-ribofuranosyl benzimidazole, a CK2 inhibitor, potentiates formyl-Met-Leu-Phe-induced NADPH oxidase activity in DMSO-differentiated HL-60 cells. Taken together, we propose that CK2 is the p47(phox) kinase, and that phosphorylation of p47(phox) by CK2 regulates the deactivation of NADPH oxidase.

Structural features of an influenza virus promoter and their implications for viral RNA synthesis

The influenza A virus, a severe pandemic pathogen, has a segmented RNA genome consisting of eight single-stranded RNA molecules. The 5' and 3' ends of each RNA segment recognized by the influenza A virus RNA-dependent RNA polymerase direct both transcription and replication of the virus's RNA genome. Promoter binding by the viral RNA polymerase and formation of an active open complex are prerequisites for viral replication and proliferation. Here we describe the solution structure of this promoter as solved by multidimensional, heteronuclear magnetic resonance spectroscopy. Our studies show that the viral promoter has a significant dynamic nature and reveal an unusual displacement of an adenosine that forms a novel (A-A) x U motif and a C-A mismatch stacked in a helix. The characterized structural features of the promoter imply that the specificity of polymerase binding results from an internal RNA loop. In addition, an unexpected bending (46 +/- 10 degrees ) near the initiation site suggests the existence of a promoter recognition mechanism similar to that of DNA-dependent RNA polymerase and a possible regulatory function for the terminal structure during open complex formation.