Identification of aroma compounds in Parmigiano-Reggiano cheese by gas chromatography/olfactometry

The volatile compounds in Parmigiano-Reggiano cheese were isolated by solvent extraction/high vacuum distillation, followed by separation into acidic, basic, water-soluble, and neutral fractions. The neutral fraction was further fractionated by a normal-phase liquid chromatography. Aroma compounds were identified using gas chromatography/Osme-mass spectrometry and confirmed with retention index of standards. Butanoic, hexanoic, octanoic, and decanoic acids are the major free fatty acids contributing to cheesy, lipolyzed aroma. Ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl propanoate, ethyl pentanoate, ethyl heptanoate, and ethyl decanoate are the major esters contributing to fruity aroma. 2-Methylbutanal, 3-methylbutanal, 2,4-hexadienal, 2-butenal, pentanal, hexanal, heptanal, diacetyl, phenylacetaldehyde, dimethyltrisulfide, and methional were identified to be odor-active. It was found that 2,3-dimethylpyrazine, 2,6-dimethyl-pyrazine, 2,5-dimethyl-3-ethylpyrazine, trimethyl-pyrazine, 5-ethyl-2-methylpyridine, 2,3-dimethyl-5-ethylpyrazine, 2,3,5-trimethyl-6-ethyl-pyrazine, furfural, and 2-furanmethanol contribute to the nutty, roasted aroma in this cheese.

Discovery of macrocyclic hydroxamic acids containing biphenylmethyl derivatives at P1', a series of selective TNF-alpha converting enzyme inhibitors with potent cellular activity in the inhibition of TNF-alpha release

SAR exploration at P1' using an anti-succinate-based macrocyclic hydroxamic acid as a template led to the identification of several bulky biphenylmethyl P1' derivatives which confer potent porcine TACE and anti-TNF-alpha cellular activities with high selectivity versus most of the MMPs screened. Our studies demonstrate for the first time that TACE has a larger S1' pocket in comparison to MMPs and that potent and selective TACE inhibitors can be achieved by incorporation of sterically bulky P1' residues.

Design and synthesis of a series of (2R)-N(4)-hydroxy-2-(3-hydroxybenzyl)-N(1)- [(1S,2R)-2-hydroxy-2,3-dihydro-1H-inden-1-yl]butanediamide derivatives as potent, selective, and orally bioavailable aggrecanase inhibitors

A pharmacophore model of the P1' site, specific for aggrecanase, was defined using the specificity studies of the matrix metalloproteinases and the similar biological activity of aggrecanase and MMP-8. Incorporation of the side chain of a tyrosine residue into compound 1 as the P1' group provided modest selectivity for aggrecanase over MMP-1, -2, and -9. A cis-(1S)(2R)-amino-2-indanol scaffold was incorporated as a tyrosine mimic (P2') to conformationally constrain 2. Further optimization resulted in compound 11, a potent, selective, and orally bioavailable inhibitor of aggrecanase.

Strain-specific iron-dependent virulence in Escherichia coli

For reasons unknown, certain Escherichia coli strains become highly virulent when injected with hemoglobin or other soluble iron sources. Two clinical isolates (virulent and nonvirulent) showed equivalent hemoglobin-mediated growth acceleration in vitro. However, when injected intraperitoneally into mice without hemoglobin, the virulent strain was cleared more slowly (t(1/2), >4 h vs. <30 min). The virulent E. coli strain had a polysialic acid-containing capsule, whereas the nonvirulent strain did not. Virulent E. coli grown at 20 degrees C (which blocks polysialylation) were cleared as rapidly as nonvirulent organisms. In another virulent E. coli strain having abundant outer membrane polysialic acid, targeted deletion of the polysialyltransferase accelerated host clearance and blocked iron-dependent virulence. The iron-dependent virulence of certain E. coli strains may represent the combined effect of slow in vivo clearance-associated, in this case, with outer membrane polysialylation coupled with accelerated growth permitted by iron compounds.

Crystal structure of alpha-momorcharin in 80% acetonitrile--water mixture

Crystals of alpha-momorcharin (MMC) were cross-linked and soaked in an 80% acetonitrile--water mixture and X-ray data were collected to 2.2 A resolution. MMC is a ribosome-inactivating protein with a sugar chain on Asn-227. In previous studies, the whole conformation of the sugar chain could not be obtained in the aqueous system. Here the structure of MMC in a low water system is shown to be similar to the native one, but the sugar chain on Asn-227 is defined by the electron density map. Several oxygen atoms of the oligosaccharide formed intramolecular hydrogen bonds to the protein moiety. The conformation of the residues in the active center is similar to that in the aqueous system. Our results show conformational alteration of the tetrasaccharide of MMC in organic media. They indicate that the oligosaccharides are more rigid in organic solvents. X-ray determination in organic media may be used to solve some structures of oligosaccharides linked to glycoproteins.

Crystal structure of the complex of concanavalin A and hexapeptide

The X-ray structure analysis of a cross-linked crystal of concanavalin A soaked with a hexapeptide molecule as a probe molecule showed an electron density corresponding to full occupation in the binding pocket. The site lies on the surface of concanavalin A and is surrounded by three symmetry-related molecules. The crystal structure of the hexapeptide complex was refined at 1.93-A resolution, to an R-factor of 19% (Rfree factor of 25%), with an RMS deviation in bond distances of 0.01 A. The model includes all 237 residues of concanavalin A, one manganese ion, one calcium ion, 95 water molecules, one glutaraldehyde molecule, one isopropanol molecule, and one hexapeptide molecule. This X-ray structure analysis also provides an approach to mapping the binding surface of crystalline protein with a probe molecule that is dissolved in the mixture of organic solvent with water or in neat organic solvent but is hardly dissolved in aqueous solution.

[Audiological findings of the aging across the urban and rural of Suzhou]

OBJECTIVE

To determine the epidemiological characteristics of old people's hearing.

METHOD

Questionnaires, physical examination, audiometry and bio-chemical tests were performed on the elders above 60 years old in part of the urban and rural area of Suzhou with random sample survey.

RESULT

A total of 1,040 individuals was investigated, among which 505 were from urban, and 535 were from rural. 33 of 505 senior citizen (6.53%) were nososacusis, 282 (55.84%) were presbycusis and 21 (4.16%) were noise-induced deafness; In the rural area, 35 of 535 (6.54%) were nososacusis, 232 (43.36%) were presbycusis, and 4 (0.75%) were noise deafness. There was significant difference of the incidence of presbycusis between urban and rural. The audiometric thresholds chart manifested that the threshold elevated with age increasing especially in high-frequency.

CONCLUSION

The etiology of hearing loss of elders was mainly due to presbycusis. The higher incidence of psychotic disorder in urban probably caused a correspondingly higher incidence of presbycusis. So the prevention and cure of some age-induced diseased (e.g. hypertension, arteriosclerosis and diabetes) may be helpful to release and improve presbycusis.

Enzyme-catalyzed condensation reaction in a mammalian alpha-amylase. High-resolution structural analysis of an enzyme-inhibitor complex

Mammalian alpha-amylases catalyze the hydrolysis of alpha-linked glucose polymers according to a complex processive mechanism. We have determined the X-ray structures of porcine pancreatic alpha-amylase complexes with the smallest molecule of the trestatin family (acarviosine-glucose) which inhibits porcine pancreatic alpha-amylase and yet is not hydrolyzed by the enzyme. A structure analysis at 1.38 A resolution of this complex allowed for a clear identification of a genuine single hexasaccharide species composed of two alpha-1,4-linked original molecules bound to the active site of the enzyme. The structural results supported by mass spectrometry experiments provide evidence for an enzymatically catalyzed condensation reaction in the crystal.

A new locus for hereditary gingival fibromatosis (GINGF2) maps to 5q13-q22

Gingival fibromatosis (GINGF) is an oral disorder characterized by enlargement of the gingiva. It occurs either as the sole phenotype or combined with other symptoms. Thus far, one GINGF locus has been mapped on chromosome 2, at 2p21, and a second possible locus has been mapped to 2p13. However, the genes responsible for this disorder have not been elucidated. We identified a four-generation Chinese GINGF family in which the disease manifests within 1 year after birth. After exclusion of the two known GINGF loci in this family, we performed a genome-wide search to map the chromosome location of the responsible gene. We identified a new locus, GINGF2, on chromosome 5q13-q22 with a maximum two-point lod score of 4.31 at D5S1721 (theta = 0.00). Haplotype analysis placed the critical region in the interval defined by D5S1491 and D5S1453. Within this region, calcium/calmodulin-dependent protein kinase IV (CAMK4) is a strong candidate.

Transcatheter closure in 354 pediatric cases of patent ductus arteriosus using five different devices

OBJECTIVE

To assess the effect of transcatheter closure of patent ductus arteriosus (PDA) by comparing five different devices.

METHODS

354 patients (135 males, 219 females) underwent transcatheter closure of PDA using the Porstmann Ivalon plug, Rashkind double umbrella, Sideris button device, Coils and Amplatzer occluders. The mean PDA diameter at its narrowest segment was 3.1 +/- 1.3 mm. Qp/Qs was 2.2 +/- 0.5. Follow-up evaluation was performed with color flow mapping of the main pulmonary artery at 24 h and 6 months after closure.

RESULTS

Successful occlusion was observed in 92% (23/25) for the Porstmann device, 98.7% (77/78) for the Rashkind device, 100% (43/43) for the Sideris device, 100% (69/69) for the Coil and 100% (139/139) for the Amplatzer device. No residual shunts were needed for the Porstmann, while 1.4%-15% of patients who received the Rashkind, Sideris, Coils or Amplatzer needed residual shunts during follow-up. There were complications of 24% (6/25) for the Porstmann, 3.8% (3/78) for the Rashkind, 1.4% (1/69) for Coils and 1.4% (2/139) for the Amplatzer. No complications were found in patients with the Sideris device.

CONCLUSION

The results showed that the Sideris device, Coils and the Amplatzer device are more effective and safer than the others for the occlusion of PDA in children.

The relationship of parenting style to self-reported mental health among two subcultures of Chinese

The results of this investigation with 127 youths (aged 16-22 years) from mainland China supported the association of recalled parent's styles (assessed by the EMBU) with adolescents' self-evaluated health status (measured by the SCL-90). Many psychosomatic symptoms and lower scores on indexes of general mental health were significantly related to higher levels of parental rejection and denial, punishing tendency, overprotection and overinvolvement and to lower levels of parental emotional warmth and comprehension. The association between parenting style and mental health status of adolescents can be generalized across genders and across the two Chinese subcultures studied (Han and Kejia ethnical groups) with moderate to fairly high confidence. The mental health status of participants suggests some differences between different subcultures or genders on several variables of the SCL-90.

Structural and kinetic analysis of the chemical rescue of the proton transfer function of carbonic anhydrase II

Histidine 64 in human carbonic anhydrase II (HCA II) functions in the catalytic pathway of CO(2) hydration as a shuttle to transfer protons between the zinc-bound water and bulk water. Catalysis of the exchange of (18)O between CO(2) and water, measured by mass spectrometry, is dependent on this proton transfer and was decreased more than 10-fold for H64A HCA II compared with wild-type HCA II. The loss of catalytic activity of H64A HCA II could be rescued by 4-methylimidazole (4-MI), an exogenous proton donor, in a saturable process with a maximum activity of 40% of wild-type HCA II. The crystal structure of the rescued complex at 1.6 A resolution shows 4-MI bound in the active-site cavity of H64A HCA II, through pi stacking interactions with Trp 5 and H-bonding interactions with water molecules. In this location, 4-MI is about 12 A from the zinc and approximates the observed "out" position of His 64 in the structure of the wild-type enzyme. 4-MI appears to compensate for the absence of His 64 and rescues the catalytic activity of the H64A HCA II mutant. This result strongly suggests that the out conformation of His 64 is effective in the transfer of protons between the zinc-bound solvent molecule and solution.

Dentinogenesis imperfecta 1 with or without progressive hearing loss is associated with distinct mutations in DSPP

Dentinogenesis imperfecta 1 (DGI1, MIM 125490) is an autosomal dominant dental disease characterized by abnormal dentin production and mineralization. The DGI1 locus was recently refined to a 2-Mb interval on 4q21 (ref. 1). Here we study three Chinese families carrying DGI1. We find that the affected individuals of two families also presented with progressive sensorineural high-frequency hearing loss (gene DFNA39). We identified three disease-specific mutations within the dentin sialophosphoprotein gene (DSPP) in these three families. We detected a G-->A transition at the donor-splicing site of intron 3 in one family without DFNA39, a mutation predicted to result in the skipping of exon 3. In two other families affected with both DGI1 and DFNA39, however, we identified two independent nucleotide transversions in exons 2 and 3 of DSPP, respectively, that cause missense mutations of two adjacent amino-acid residues in the predicted transmembrane region of the protein. Moreover, transcripts of DSPP previously reported to be expressed specifically in teeth are also detected in the inner ear of mice. We have thus demonstrated for the first time that distinct mutations in DSPP are responsible for the clinical manifestations of DGI1 with or without DFNA39.

Inducible mutagenesis in TEPC 2372, a mouse plasmacytoma cell line that harbors the transgenic shuttle vector lambdaLIZ

The plasmacytoma cell line, TEPC 2372, was derived from a malignant plasma cell tumor that developed in the peritoneal cavity of a BALB/c mouse that harbored the transgenic shuttle vector for the assessment of mutagenesis in vivo, lambdaLIZ. TEPC 2372 was found to display the typical features of a BALB/c plasmacytoma. It consisted of pleomorphic plasma cells that secreted a monoclonal immunoglobulin (IgG2b/lambda), was initially dependent on the presence of IL-6 to grow in cell culture, contained a hyperdiploid chromosome complement with a tendency to undergo tetraploidization, and harbored a constitutively active c-myc gene by virtue of a T(6;15) chromosomal translocation. TEPC 2372 was further characterized by the ability to respond to in vitro exposure with 4-NQO (4-nitroquinoline-1-oxide), an oxidative model mutagen, with a vigorous dose-dependent increase in mutagenesis that peaked at a 7.85-fold elevation of mutant rates in lambdaLIZ when compared to background mutant rates in untreated controls. Cotreatment with 4-NQO and BSO (buthionine sulfoximine), a glutathione-depleting compound that causes endogenous oxidative stress, resulted in a 9.03-fold increase in the mutant frequency in lambdaLIZ. These results demonstrated that TEPC 2372, the malignant plasma cell counterpart of the lambdaLIZ-based in vivo mutagenesis assay, may be useful as an in vitro reference point for the further elucidation of oxidative mutagenesis in lymphoid tissues.

Interactions among subunits of human Arp2/3 complex: p20-Arc as the hub

The Arp2/3 complex is critical for nucleation and crosslinking of actin filaments. To gain insight into its subunit topology and assembly pathway, we systematically examined interactions among subunits of human Arp2/3 complex by yeast two-hybrid assays. It was shown that p20-Arc was able to interact with p21-Arc, p34-Arc, and p16-Arc, respectively. In contrast, p41-Arc only interacted with p20-Arc/p16-Arc heterodimer. In addition, we found that structural integrity was important for association between p20-Arc and p21-Arc, while the N-terminal half of p34-Arc was dispensable for its binding to p20-Arc. Our data suggest a key role of p20-Arc and a multistep pathway for the complex formation.

Crystal structure of the complex of concanavalin A and tripeptide

The X-ray structure analysis of a cross-linked crystal of concanavalin A soaked with the tripeptide molecule as the probe molecule showed electron density corresponding to full occupation in the binding pocket. The site lies on the surface of concanavalin A and is surrounded by three symmetry-related molecules. The crystal structure of the tripeptide complex was refined at 2.4-A resolution to an R-factor of 17.5%, (Rfree factor of 23.7%), with an RMS deviation in bond distances of 0.01 A. The model includes all 237 residue of concanavalin A, 1 manganese ion, 1 calcium ion, 161 water molecules, 1 glutaraldehyde molecule, and 1 tripeptide molecule. This X-ray structure analysis also provides an approach to mapping the binding surface of crystalline protein with a probe molecule that is dissolved in a mixture of organic solvent with water or in neat organic solvent but is hardly dissolved in aqueous solution.

Distribution of ferritin and redox-active transition metals in normal and cataractous human lenses

Previous studies have shown that lenticular levels of Fe and Cu are elevated in age-related cataract. However, it is not known if these metals are present in a state that is permissive for redox reactions that may lead to the formation of free radicals. In addition, there is little data available concerning the concentration and lenticular distribution of ferritin, the major intracellular Fe-sequestering protein, in the lens. The aim of the present work was therefore to determine the distribution of ferritin and the redox-availability of Fe and Cu in healthy and cataractous lenses. Lens ferritin distribution was assessed by ELISA and immunohistochemistry. A modified ELISA detected ferritin in an 'insoluble' lens protein fraction. Ferritin levels were not significantly different in the cortex vs nucleus of healthy lenses. In contrast, ferritin levels in the cataractous lens nuclei appeared to be 70% lower compared to the cortex. This was at least partially due to the presence of ferritin within an insoluble protein fraction of the homogenized lenses. In normal lenses, ferritin staining was most intense in the epithelium, with diffuse staining observed throughout the cortex and nucleus. The redox-availability of lenticular metals was determined using: (1) autometallography; (2) Ferene-S as a chromogenic Fe chelator; and (3) NO release from nitrosocysteine to probe for redox-active Cu. The autometallography studies showed that the cataractous lenses stained more heavily for redox-active metals in both the nucleus and cortex when compared to age-matched control lenses. Chelatable Fe was detected in homogenized control lenses after incubation with Ferene-S, with almost three-fold higher levels detected in the cataractous lenses on average. The Cu-catalysed liberation of NO from added nitrosocysteine was not demonstrated in any lens sample. When exogenous Cu (50 n M) was added to the lenses, it was rapidly chelated. The cataractous samples were approximately twice as effective at redox-inactivation of added Cu. These studies provide evidence that a chelatable pool of potentially redox-active Fe is present at increased concentrations in human cataractous lenses. In contrast, it seems that lenticular Cu may not be readily available for participation in redox reactions.

Stochastic resonance on a circle without excitation: physical investigation and peak frequency formula

In this article the existence of stochastic resonance (SR) without external force in a simplified circular system for different values of the control parameter b is considered. The average power spectra are calculated as well as the signal-to-noise ratio as a measure for stochastic resonance. It is shown that in the monostable and semistable (b<1 and b=1) cases coherent oscillations occur and SR exists. For the case b>1, the system is oscillatory and noise plays only a destructive role; therefore no SR occurs. The rotation number of the system is calculated and compared to the peak frequency of the power spectrum. Although the coincidence in the noisy case is not as good as that in the deterministic case, we can derive an empirical formula between the peak frequency of the power spectrum and the rotation number of the system, which is in good agreement with results of numerical simulations.

[Insulin-like growth factor-I(IGF-I), and its binding protein-3 (IGFBP-3) correlated with fetal development]

OBJECTIVE

To study the relations between IGF-I, IGFBP-3 and human fetal growth.

METHODS

The blood samples of maternal serum (MS) and umbilical cord serum (UCS) from 81 cases with singleton term pregnancy including 38 cases of normal pregnancy (NP), 20 cases of gestational diabetic mellitus (GDM), 23 cases of macrosomia of non-diabetic pregnancy (MNDP) were examined for IGF-I and IGFBP-3 levels by immunoassay kit from DSL, USA.

RESULTS

IGF-I in MS of NP and MNDP showed a positive correlation with birth weight (BW) (r = 0.653 and r = 0.640 respectively, both P < 0.01). IGF-I of MS in MNDP was higher than that in NP (P < 0.05). IGF-I of MS and UCS in GDM were higher than that in NP (P < 0.05). IGF-I and IGFBP-3 of UCS in these three groups were significantly lower than that of MS (P < 0.001).

CONCLUSION

Detection of IGF-I in MS can assess fetal intra-uterus growth, birth weight and has certain value of predicting macrosomia. IGF-I and IGFBP-3 play important roles for human fetal growth.

Evidence that MK-801 stimulates intraoral intake by acting on hepatic afferents

Satiety signals from the gastrointestinal tract travel via vagal afferents to the nucleus of the solitary tract (NTS) in the brain stem, the first central relay in a neural network which controls food intake. The non-competitive NMDA antagonist MK-801 facilitates food intake in rats by acting on the NTS. Here we report that hepatic portal vein infusion of MK-801 (25 or 50 microg/kg) increases intake of an intraorally infused 1 M solution of sucrose (by 113 +/- 9 and 132 +/- 11%, respectively) and that this effect is prevented by hepatic vagotomy. By contrast, jugular vein infusion of MK-801 fails to increase sucrose intake but induces forward locomotion, indicating activation of a central mechanism. These data suggest that MK-801 can stimulate food intake by acting peripherally on hepatic vagal afferents.

Risk factors for development of diabetes mellitus in women with a history of gestational diabetes mellitus

OBJECTIVE

To determine whether diabetes recurs in their later life when women have a history of gestational diabetes mellitus (GDM) or abnormal glucose tolerance test (impaired glucose tolerance, IGT).

METHODS

Three groups of women were investigated at 5-10 years postpartum. GDM group (n = 45) had been diagnosed as having GDM in their previous pregnancy. IGT group (n = 31) had a history of abnormal glucose tolerance test during previous pregnancy. Normal control group (n = 39) was normal previous pregnant population. Their previous obstetric and medical histories were thoroughly reviewed. Fasting plasma glucose (FPG) and oral glucose (75 g) tolerance test (OGTT) were repeated in all women.

RESULTS

Diabetes mellitus (DM) was diagnosed in 33.3% of patients in the GDM group, while in 9.7% in the IGT group and in 2.6% in the normal control group. Incidence of recurring DM in later life was significant higher in the GDM group (P = 0.017). When one or more blood glucose values exceeding WHO criteria for diagnosis of diabetes in their previous pregnancy, the incidence of DM in later life was 60% (3/5, including GDM in women having four abnormal OGTT values), 41.7% (5/12) in women having three, 25% (7/28) in women having two and 9.7% (3/31) in women having one. The women with DM, also with a history of GDM and abnormal OGTT in previous pregnancy, tends to have a high pregnant body mass index (BMI > 25 kg/m2).

CONCLUSION

The women suffering from GDM during previous pregnancy have a high risk of recurrence DM. Two or more abnormal OGTT values during pregnancy, blood glucose level exceeding the maximal values at 1 and 2 hours after oral glucose loading and high pregnant BMI are concluded to be useful factors in predicting the recurring DM in their later life.

Phase I pharmacokinetic trial of perillyl alcohol (NSC 641066) in patients with refractory solid malignancies

Perillyl alcohol (POH) is a monoterpene with anticarcinogenic and antitumor activity in murine tumor models. Putative mechanisms of action include activation of the transforming growth factor beta pathway and/or inhibition of p21ras signaling, leading to differentiation or apoptosis. In this Phase I trial, 17 patients took POH p.o. three times daily for 14 days of each 28-day cycle. The starting dose of POH was 1600 mg/m2/dose, with escalations to 2100 and 2800 mg/m2/dose in subsequent cohorts. Chronic nausea and fatigue were dose-limiting toxic effects at 2800 mg/m2. Grade 1-2 hypokalemia was common at 2100 and 2800 mg/m2. Although POH could not be detected in plasma, two of its metabolites, dihydroperillic acid (DHPA) and perillic acid (PA), were measured in plasma and urine on days 1 and 15 after the first and last doses of POH, respectively. Both area under the concentration versus time curve and peak plasma concentration (Cmax) values increased with dose and exhibited high intersubject variability. Day 15 DHPA Cmax values ranged from a mean +/- SD of 22.6+/-12 microM at 1600 mg/m2/dose to 42.4+/-15.24 microM at 2800 mg/m2/dose. Corresponding mean +/- SD Cmax values for PA were 433.2+/-245.8 and 774.1+/-439.6 microM. One patient treated at the 2800 mg/m2/dose had markedly prolonged plasma levels of both PA and DHPA and developed grade 3 mucositis. POH treatment did not consistently alter the expression of p21ras, rap1, or rhoA in peripheral blood mononuclear cells obtained from patients treated at the highest dose level. The metabolites PA and DHPA did not change expression or isoprenylation of p21ras in MCF-7 breast or DU145 prostate carcinoma cells at concentrations that exceeded those achieved in patient plasma after POH treatment. We conclude that POH at 1600-2100 mg/m2 p.o. three times daily is well tolerated on a 14-day on/14-day off dosing schedule. Inhibition of p21ras function in humans is not likely to occur after POH administration at safe doses of the present oral formulation.

Pumped biochemical reactions, nonequilibrium circulation, and stochastic resonance

Based on a master equation formalism for mesoscopic, unimolecular biochemical reactions, we show the periodic oscillation arising from severe nonequilibrium pumping is intimately related to the periodic motion in recently studied stochastic resonance (SR). The white noise in SR is naturally identified with the temperature in the biochemical reactions; the drift in the SR is associated with the circular flux in nonequilibrium steady state (NESS). As in SR, an optimal temperature for biochemical oscillation is shown to exist. A unifying framework for Hill's theory of NESS and the SR without periodic forcing is presented. The new formalism provides an analytically solvable model for SR.

[A preliminary meta-analysis of 36 studies on impairment of intelligence development induced by iodine deficiency]

OBJECTIVES

Since 1980 s', numerous studies on intelligence quotient (IQ) have documented, in the areas prevalent with severe, moderate and even mild iodine deficiency, which is a risk factor for retardation in mental development there. It was purposed for this paper to quantify the relationship between iodine deficiency and mental development in children and to explore the etiological role of iodine deficiency in mental retardation and the protective effects on children's intelligence of iodine supplementation.

METHODS

A total of 59 independent investigations published during 1980 and 1998 were selected for meta-analysis, including 20 studies on intelligence determined by Raven's Test and 39 by China Benit Scale.

RESULTS

Homogeneity test showed that there was no significant difference in baseline features between two groups (P > 0.05). The hypothesis testing showed that the homogeneity of each study group was obviously statistically significant (P > 0.05). The results demonstrated that IQ in children at risk for iodine deficiency showed a marked drop by 8.94 points with Raven's Test and by 10.80 points with China Binet Scale, respectively, with an average drop of 10 points. Substantial evidence now available has showed that mental retardation can be prevented by effective correction of iodine deficiency through iodine supplement either iodized salt or iodized oil, which is confirmed by an obvious increase in 11.5 points of IQ in average, and in 11.85 by Raven's Test and 11.64 by China Binet Scale, respectively.

CONCLUSIONS

Iodine nutrition plays an important and positive role in brain development. Iodine deficiency leads to loss of 10 points of IQ and 11.5 points can be gained for children in the iodine deficiency areas after significant iodine supplement.