Conjugated linoleic acid inhibits differentiation of pre- and post- confluent 3T3-L1 preadipocytes but inhibits cell proliferation only in preconfluent cells

Conjugated linoleic acid (CLA; 18:2) is a group of isomers (mainly 9-cis, 11-trans and 10-trans, 12-cis) of linoleic acid. CLA is the product of rumen fermentation and can be found in the milk and muscle of ruminants. Animals fed CLA have a lower body fat content. The objective of this study was to establish the possible mechanisms by which CLA affects adipogenesis. 3T3-L1 is a well-established cell line that is used extensively in studying adipocyte biology. These cells typically grow in a culture medium until they reach confluence, at which time they are induced to differentiate by hormonal treatment (d 0). Treatment of 3T3-L1 cells with 25 to 100 micromol/L CLA inhibited differentiation in a dose-dependent manner, while linoleic acid treatment did not differ from DMSO-treated controls. Continuous treatment from d -2, -1, 0 or 2 to d 8 and treatment from d -2 to d 0 and from d 0 to d 2 inhibited differentiation. Differentiation was monitored morphologically (oil Red-O staining), enzymatically (reduction of activity of glycerol-3-phosphate dehydrogenase), and by northern analysis of peroxisome proliferator-activated receptor gamma2, CCAAT/enhancer binding protein alpha and adipocyte specific protein 2 mRNA. CLA inhibited cell proliferation of nonconfluent cells but did not affect cell division of confluent cells, as indicated by 5-bromo-2'-deoxyuridine incorporation and mitochondria metabolism. Therefore, CLA inhibited differentiation before confluence and during induction. However, cellular proliferation was only inhibited prior to induction. These results imply that fat reduction caused by CLA treatment may be attributed to its inhibition of both proliferation and differentiation of preadipocytes in animals.

Localization of Niemann-Pick C1 protein in astrocytes: implications for neuronal degeneration in Niemann- Pick type C disease

Niemann-Pick type C disease (NP-C) is an inherited neurovisceral lipid storage disorder characterized by progressive neurodegeneration. Most cases of NP-C result from inactivating mutations of NPC1, a recently identified member of a family of genes encoding membrane-bound proteins containing putative sterol sensing domains. By using a specific antipeptide antibody to human NPC1, we have here investigated the cellular and subcellular localization and regulation of NPC1. By light and electron microscopic immunocytochemistry of monkey brain, NPC1 was expressed predominantly in perisynaptic astrocytic glial processes. At a subcellular level, NPC1 localized to vesicles with the morphological characteristics of lysosomes and to sites near the plasma membrane. Analysis of the temporal and spatial pattern of neurodegeneration in the NP-C mouse, a spontaneous mutant model of human NP-C, by amino-cupric-silver staining, showed that the terminal fields of axons and dendrites are the earliest sites of degeneration that occur well before the appearance of a neurological phenotype. Western blots of cultured human fibroblasts and monkey brain homogenates revealed NPC1 as a 165-kDa protein. NPC1 levels in cultured fibroblasts were unchanged by incubation with low density lipoproteins or oxysterols but were increased 2- to 3-fold by the drugs progesterone and U-18666A, which block cholesterol transport out of lysosomes, and by the lysosomotropic agent NH4Cl. These studies show that NPC1 in brain is predominantly a glial protein present in astrocytic processes closely associated with nerve terminals, the earliest site of degeneration in NP-C. Given the vesicular localization of NPC1 and its proposed role in mediating retroendocytic trafficking of cholesterol and other lysosomal cargo, these results suggest that disruption of NPC1-mediated vesicular trafficking in astrocytes may be linked to neuronal degeneration in NP-C.

Human leukocyte antigen polymorphisms in the Taiwanese population

Polymorphisms of human leukocyte antigens (HLA) are important in transplantation medicine, anthropologic studies, and paternity testing. We investigated the polymorphisms of HLA classes I and II in the Taiwanese population by means of serologic typing and polymerase chain reaction (PCR) analysis with sequence-specific primers. We calculated the HLA-A, -B, and -C gene frequencies in 673 Taiwanese subjects and the HLA-DRB1, and HLA-DQB1 gene frequencies in 204 subjects with available DNA samples. Haplotype frequencies and linkage-disequilibrium were analyzed on the basis of these data. The common HLA class I antigens were A11 (gene frequency, 34.9%), A2 (29.3%), A24 (15.8%), and A33 (9.8%); B60 (21.9%), B46 (13.1%), B58 (9.7%), and B13 (8.5%); and Cw1 (18.8%), Cw7 (15.3%), and Cw10 (10.7%). The common HLA-DRB1 and HLA-DQB1 alleles were DRB1*12 (15.2%), DRB1*09 (15.2%), DRB1*08 (12.0%), and DRB1*04 (12.0%); and DQB1*0301 (23.5%), DQB1*0303 (15.2%), DQB1*0601 (14.5%), and DQB1*02 (10.8%). The common two-locus haplotypes were A2-B46 (frequency, 9. 7%), A11-B60 (9.6%), and A33-B58 (6.8%); DRB1*09-DQB1*0303 (14.9%), DRB1*12-DQB1*0301 (14.2%), and DRB1*08-DQB1*0601 (10.7%). This study is the first to report the gene frequencies of HLA-DQB1 alleles and the common HLA-DR-DQ haplotypes among Taiwanese. Comparison of our results with those from two other Chinese populations in mainland China reveals that Taiwanese are more closely related to southern Han than to northern Han Chinese.

Position of poly(methyl methacrylate) and silicone intraocular lenses after phacoemulsification

PURPOSE

To compare the positional change of poly(methyl methacrylate) (PMMA) and silicone intraocular lenses (IOLs) in vivo after phacoemulsification.

SETTING

Taipei Municipal Yang-Ming Hospital, Taipei, Taiwan.

METHODS

A prospective study of 70 cataractous eyes treated by phacoemulsification with IOL implantation was carried out. The eyes were randomized into 2 groups based on IOL type: 1-piece PMMA IOL; 3-piece silicone IOL. The amount of IOL tilt and decentration was measured and anterior chamber depth (ACD) determined by Scheimpflug photography using an anterior eye segment analysis system (EAS-1000, Nidek). All eyes were examined 1 week and 1 to 6 months after surgery.

RESULTS

No statistically significantly differences were found in the amount of tilt and decentration between 2 IOL types throughout the study. The ACDs were relatively constant in both groups through the early postoperative periods.

CONCLUSION

The stability of PMMA and silicone IOLs were the same after phacoemulsification.

A preliminary study of the mental health of young migrant workers in Shenzhen

The aim of this study is to examine the mental health status of young migrant workers in Shenzhen. Using the Symptoms Check List-90 (SCL-90), Eysenck Personality Questionnaire, Social Support Scale and Mental Health Questionnaire for Laborers, 371 migrant workers who came from inland areas of China and 100 local workers were investigated. The SCL-90 profile of migrant workers was also compared to the SCL-90 norms provided by general people in China. The SCL-90 results showed that the total scores, the average scores of the positive symptoms, the three factor scores of obsessionality, interpersonal sensitivity and phobia in migrant workers were significantly higher than those in the local workers. According to the multivariate analysis, the amount of contribution to mental health, in descending order, was neuroticism, psychological pressure, income, home sickness, marital or love problems, extroversion and introversion, living conditions and social status. The mental health status of young migrant workers in Shenzhen was poorer than that of their local counterparts, as well as people in China on the SCL-90. It is recommended that mental health workers should help migrant workers adjust to the new urban environment by providing psychological counseling and other relevant treatment facilities.

HLA-DRB1*0701 and DRB1*1401 are associated with genetic susceptibility to psoriasis vulgaris in a Taiwanese population

We analysed the allelic frequencies of class II human leucocyte antigen (HLA)-DRB1, DQA1, DQB1 and DPB1 by polymerase chain reaction/sequence-specific oligonucleotide probe hybridization typing in 76 Taiwanese psoriasis vulgaris (PSV) patients and 238 Taiwanese non-psoriatic controls. The analysis revealed the following: (i) the DRB1*0701 allele was positively associated with PSV (relative risk, RR = 6.4, corrected P-value, Pc < or = 0.001); (ii) the DRB1*1401 allele was positively associated with type I PSV (age at onset < 40 years) (RR = 3.5, Pc < or = 0.001); (iii) the DQA1*0501 allele was negatively associated with PSV (RR = 0.4, Pc < or = 0.001); (iv) there was no significant association of HLA-DP genes with PSV; and (v) there was a strong association of beta-chain phenylalanine at position 37 (Phe 37) and glutamate or glutamine at position 74 (Glu 74/Gln 74) with PSV (RR = 3.5, Pc < or = 0.001 for the association of Phe 37 with PSV: RR = 2.2, Pc < or = 0.001 for the association of Glu 74/Gln 74 with PSV). The positive association between PSV and the DRB1*0701 allele is consistent with previous reports. The negative association of the DQA1*0501 allele is reported only in Finland, whereas the positive association between PSV and the DRB1*1401 allele has never been described before. Trans-racial studies may shed further light on the association of class II HLA alleles or other closely linked genes with the development of PSV. Phe 37 (a large, non-polar amino acid) and Glu 74/Gln 74 (both negatively charged amino acids) were the polymorphic residues in pockets 9 and 4, respectively, of the beta-chain, which may have increased their affinity for the small non-polar amino acids and basic amino acids of the psoriatic antigen peptide, thereby activating the T lymphocytes. This finding may facilitate the identification of a psoriatic antigen.

Nuclear factor I regulates expression of the gene for phosphoenolpyruvate carboxykinase (GTP)

Nuclear factor-I (NFI) binds to the phosphoenolpyruvate carboxykinase (GTP) (PEPCK) gene promoter immediately 5' to the cAMP regulatory element (CRE). This suggests an interaction between NFI and factors that bind the CRE. Of the four NFI isoforms expressed in mammalian tissues, NFI-A and -B stimulate basal transcription from the PEPCK gene promoter in HepG2 cells, while NFI-C and -X are slightly inhibitory. All four NFI isoforms abrogate the 20-fold protein kinase Ac (PKAc)-mediated induction of transcription from the PEPCK gene promoter. Normal PKAc-mediated induction was noted when the CRE was moved 10 base pairs 3' of its original location. However if the CRE was moved 5 base pairs 3', placing it out of phase with the other elements in the promoter, or moved 5' to -285 (the P3(I) site in the promoter), some PKA-mediated stimulation was lost. The NFI-C isoform effectively inhibited PKAc induction regardless of the relative positions of the CRE and the NFI binding sites. NFI-C also abrogated cAMP regulatory element-binding protein (CREB)-induced activity of wild type and mutant PEPCK promoters. There was some cooperativity in the binding of CREB and NFI to their respective binding sites but this did not appear to be physiologically important.

Familial transmission of human T-lymphotropic virus type 1 (HTLV-1) in patients with adult T-cell leukemia/lymphoma or HTLV-1-associated myelopathy

The seroprevalence of human T-lymphotropic virus type 1 (HTLV-1) in Taiwan is 0.48%. In this study, we investigated the patterns of intrafamilial transmission of HTLV-1 in Taiwanese patients with adult T-cell leukemia/lymphoma (ATL/L) or tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM). Fifteen index patients (9 men, 6 women, aged 31-71 yr), 13 with ATL/L, and two with TSP/HAM, and 98 relatives were included. Of the 98 relatives, 23 were seropositive for HTLV-1. Spouses of 11 patients were studied. Seven of eight wives of male patients but none of the three husbands of female patients were HTLV-1 carriers. Mother-to-child transmission was found in seven of 13 families and in 15 of 75 children tested. The correlation of breast-feeding with seropositivity in two families with seropositive mothers indicates its important role in vertical transmission of HTLV-1. Our findings suggest that husband-to-wife and mother-to-child transmission are the main forms of intrafamilial transmission of HTLV-1 in Taiwan, a nonendemic area. Screening for HTLV-1 in family members of patients with ATL/L or TSP/HAM, and seropositive blood donors, may be warranted. Seropositive individuals should be educated to prevent the spread of the virus through sexual contact and breast feeding.

CCAAT/enhancer-binding protein beta is not affected by tetrachlorodibenzo-p-dioxin (TCDD) inhibition of 3T3-L1 preadipocyte differentiation

The differentiation of 3T3-L1 preadipocytes is induced by the coordinate activation of trans-acting factors in response to inducers. Depending on the time of treatment, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was effective in inhibiting 3T3-L1 preadipocyte differentiation and the expression of differentiation-dependent trans-acting factors. Based on glycerol-3-phosphate dehydrogenase activity, in the differentiation of 3T3-L1 cells was decreased by 70% in cells treated with TCDD before the induction of differentiation, 25% during induction, and not at all after induction. This time-dependent inhibition of cell differentiation by TCDD was correlated with the levels of aryl hydrocarbon receptor (AhR). TCDD treatment decreased the mRNA levels of C/EBP alpha and PPAR gamma 2 but did not affect the mRNA levels of RXR alpha and RAR alpha. Furthermore, TCDD did not change the mRNA or protein levels of C/EBP beta, which is thought to play a role in inducing C/EBP alpha and PPAR gamma 2 expression. These results suggest that TCDD inhibited 3T3-L1 preadipocyte differentiation through the AhR pathway, and the change of C/EBP beta mRNA and protein was not involved in reducing mRNA expression of C/EBP alpha and PPAR gamma 2.

Inhibition of increases of transcription factor mRNAs during differentiation of primary rat adipocytes by in vivo 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) treatment

Understanding the differentiation pathway of adipocytes is an important first step for controlling human and animal fat deposition. Although many studies have been done on adipogenesis, most have utilized established cell lines rather than isolated primary cells. We have studied primary preadipocyte differentiation to determine whether the cell lines reflect the situation in vivo. In this study, mRNA of several transcription factors and adipocyte-related enzymes, isolated from cultured differentiating primary rat inguinal and epididymal cells, followed the same pattern of change during differentiation as seen in differentiating 3T3-L1 cells. As the cells differentiated, mRNA for C/EBPalpha, PPARgamma2, aP2 and lipoprotein lipase (LPL) increased, C/EBPbeta decreased and CHOP remained at a low level. Previously we have shown that in vivo treatment with TCDD (2,3,7,8- tetrachlorodibenzo-p-dioxin) inhibits in vitro adipogenesis and the increase of mRNAs for glycerol-3-phosphate dehydrogenase and LPL (Tox. Lett. 84:55, 1996). TCDD treatment in vivo also inhibited the increase of mRNA for the PPARgamma2, aP2 and C/EBPbeta during differentiation of the isolated preadipocytes. C/EBPbeta and CHOP mRNAs were unaffected. Due to the similarity of changes of the transcription factor mRNAs for primary and 3T3-LI cells during differentiation and after TCDD treatment, 3T3-L1 cells appear to provide a good model for more clearly defining the route of adipogenesis and TCDD inhibition.

Effect of retinoic acid on differentiation of cultured pig preadipocytes

We studied the effect of retinoic acid on the differentiation of cultured porcine preadipocytes. Porcine preadipocytes were cultured in serum-free medium (DME/F12 medium containing 100 nM insulin, 10 micrograms/mL transferrin, and 50 ng/mL hydrocortisone). Addition of increasing amounts of retinoic acid (1 nM to 20 microM) to the medium reduced glycerol-3-phosphate dehydrogenase (GPDH) activity, a late marker of preadipocyte differentiation. At lower concentrations (0.1 to 10 nM), retinoic acid had no effect on the GPDH activity. Addition of retinoic acid (10 microM) for 24 h during the early stage of development (d 1) greatly inhibited the GPDH activity. After the cells were differentiated, however, retinoic acid no longer had any effect. Therefore, retinoic acid was most effective in undifferentiated cells. Following a 24-h exposure of porcine preadipocytes to retinoic acid at d 1, Northern blot analysis showed that there was a decrease in lipoprotein lipase and adipsin mRNA levels. The results suggest that retinoic acid is a potent inhibitor of porcine preadipocyte differentiation in primary culture.

Insulin and hydrocortisone, but not triiodothyronine, are required for the differentiation of pig preadipocytes in primary culture

The objective of this study was to establish optimal conditions for the primary culture of pig preadipocytes. We cultured pig preadipocytes for 10 d and studied the effects of insulin, hydrocortisone, and triiodothyronine (T3) added to serum-free basal medium on differentiation and gene expression of lipoprotein lipase an early marker, and adipsin, a late marker of preadipocyte differentiation. Insulin alone and hydrocortisone alone stimulated a low level of cell differentiation, as indicated by an increase in glycerol-3-phosphate dehydrogenase activity. When added together, insulin and hydrocortisone had a synergistic effect on cell differentiation. When combined with insulin or hydrocortisone, T3 had no effect on cell differentiation, indicating that T3 is not required in porcine preadipocyte culture. Gene expression studies also showed that removal of insulin or hydrocortisone from complete serum-free medium reduced both early and late marker mRNA. As expected, removal of T3 had no effect on the gene expression of early and late marker mRNA. We conclude that insulin and hydrocortisone, but not T3, are required for the differentiation of pig preadipocytes in primary culture.

Inhibitors of preadipocyte differentiation induce COUP-TF binding to a PPAR/RXR binding sequence

Inhibition of preadipocyte differentiation by 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) or retinoic acid (RA) identified another transcription factor which appears to be important for preadipocyte differentiation. Within 15 min of treating 3T3-L1 cells with TCDD, the aryl hydrocarbon receptor (AhR) is present within the cell nucleus, and increased binding of COUP-TF to an oligomer of the PPAR gamma 2/RXR binding sequence (ARE7) occurs. Following 2 days of RA treatment, increased binding of COUP-TF to the ARE7 oligomer also occurs. In untreated preadipocytes, COUP-TF mRNA increased at confluence and then decreased after induction. TCDD treatment did not alter COUP-TF mRNA changes. Dephosphorylating the nuclear extracts from TCDD and RA-treated cells eliminated binding of COUP-TF to ARE7. This is the first indication that COUP-TF may play a role in preadipocyte differentiation and that COUP-TF binding to DNA is correlated with TCDD and RA-induced phosphorylation.

Wide hybridization between Brazilian soybean cultivars and wild perennial relatives

Employing a different culture strategy, we obtained a greatly improved frequency of embryo rescue in intersubgeneric soybean hybrids. Successful crosses were obtained in 31 different genotype combinations between nine Brazilian soybean lines as the female parents and 12 accessions from Glycine canescens, G. microphylla, G. tabacina and G. tomentella. The hybrid pod retention rate dropped to about 10% during the first 8 days after pollination and stayed largely unchanged up to the 20th day. Immature harvested seeds fell into three size groups: Group 1, smaller than 1.3 mm (mostly empty seed coats); Group 2, 1.9-5.0 mm; Group 3, larger than 5 mm (from selfing). A total of 90 putative hybrid embryos were rescued using a highly enriched B5 medium to nourish the newly dissected embryos. The growing embryos were then placed in a high osmotic, modified B5 medium to induce maturation and dormancy. Schenk and Hildebrandt medium was used to germinate the dormant, partially dehydrated, physiologically mature embryos. Approximately 37% of the rescued embryos developed into plantlets in vitro, and approximately 8% grew into mature plants in the greenhouse. Morphological, cytological and isoenzyme patterns confirmed the hybrid status of all seven mature plants, all of which were generated using G. tomentella G 9943 as the paternal parent. It was observed that all soybean lines crossed with G 9943 were capable of producing mature hybrid plants. There was no correlation between the initial size of Group 2 seeds and plant survival rate. The hybrids were cloned by grafting and treated with colchicine. One of the treated plants displayed chromosome doubling.

Catalytic and EPR studies of the beta E204Q mutant of the chloroplast F1-ATPase from Chlamydomonas reinhardtii

The mutation E204Q in the beta subunit of the chloroplast F1-ATPase was made by biolistic transformation of Chlamydomonas reinhardtii. The yield of chloroplast F1-ATPase (CF1) purified from thylakoids was unaltered, suggesting that the mutation did not affect protein assembly. However, photoautotrophic growth of Chlamydomonas strains containing beta E204Q was virtually abolished, and the effect of the mutation on the light-driven ATPsynthase activity catalyzed by purified thylakoids was comparable to the change in the photoautotrophic growth rate. The loss of ATPsynthase activity in the mutant was not the result of uncoupling. Addition of wild-type CF1 to mutant thylakoids depleted of CF1 reconstituted ATPsynthase activity indicating that the mutation did not affect assembly of F0. Furthermore, the mutant CF1F0 was capable of catalyzing ATPase-dependent proton pumping as measured by fluorescence quenching of 9-amino acridine. Although the mutation significantly affected the apparent kcat/K(m) of the Mg(2+)-ATPase activity of the purified CF1-ATPase, no significant effect on the apparent kcat was observed with the mutant compared to wild-type. No significant changes in the ability of Mg2+ or Mn2+ to serve either as a cofactor or as an inhibitor of ATPase activity were observed in the mutants relative to the wild-type CF1-ATPase. EPR spectra were also taken of VO2+ bound at catalytic site 3 in its latent form. In a large fraction of the latent enzyme, a carboxyl group has displaced the nucleotide-phosphate coordination to the metal which results in the free-metal inhibited form (M3). No significant effects on the gII and AII 51V hyperfine parameters were observed between wild-type and mutant. However, the mutation increased the abundance of the M3 form relative to the M3-N3 form (metal-nucleotide-coordinated form). On the basis of these results, beta E204 is not the carboxyl group that displaces the nucleotide phosphate as a ligand to form the free-metal inhibited enzyme form which predominates in site 3 in the latent state. Instead, the data are consistent with a role in which beta E204 is essential to protonate an inorganic phosphate-oxygen to make that oxygen a good leaving group to facilitate ATP synthesis and, via this role in H-bonding, increases the abundance of the functional metal-nucleotide complex bound to the catalytic site.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) inhibition of fat cell differentiation

Fat and liver are the major sites for the deposition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) given in vivo to rats. Although a great deal of information is available on the effects of TCDD in liver, very little is known of the effects in fat. The epididymal fat pads were removed and the stromal-vascular cells, released by collagenase digestion, were put into primary culture, 2, 4, 6 and 8 days after intubating 175 micrograms/kg TCDD into male Sprague-Dawley rats. Following 7 days in culture, the cells were examined morphologically, and assayed for an early (lipoprotein lipase, LPL) and late marker of fat cell differentiation (glycerol-3-phosphate dehydrogenase, GPDH). With rats sacrificed 6 or 8 days after TCCD intubation, the harvested cells from pair-fed rats contained significantly more fat and had a significantly higher level of GPDH enzyme activity, indicating more differentiation. The mRNA for LPL and GPDH genes was also higher for cells from pair-fed rats. In addition, for the rats that were sacrificed 4-8 days after TCDD intubation, despite similar food intake, the pair-fed control rats gained more total body weight than the treated rats. Although there was a body weight difference, there was no significant different between the weights of the epididymal fat pads. This is the first report to demonstrate that TCDD inhibits the differentiation of fat cells.

Effect of full feed and early feed restriction on broiler performance, abdominal fat level, cellularity, and fat metabolism in broiler chickens

Three hundred sixty Peterson x Arbor Acres chicks were fed two feed regimens to compare their effects on adipose cellularity, adipocyte lipolysis, hepatic glucose oxidation, adipocyte lipogenesis, bird performance, and abdominal fat level. Broilers in the first regimen had ad libitum access to feed throughout the 7-wk experiment, whereas broilers in the second regimen consumed feed at will throughout the experiment except that they were subjected to feed restriction (1.49 kcal/g BW2/3 daily) from 7 to 12 d of age (DOA). No differences in mean body weights were observed between the full-fed and restricted males and combined sex broilers at 49 DOA. Feed conversion and abdominal fat levels of female and combined sex were lower (P < .05) for the restricted than full-fed broilers. No differences in adipocyte numbers based either on whole abdominal fat pads at 28 and 42 DOA or per gram fat at 42 DOA were observed between broilers fed the two feed regimens. However, the adipocyte numbers per gram fat at 28 DOA were greater (P < .05) for the restricted broiler than for the broilers that ate freely. Lipolysis based per million adipocytes was not different between the treatments at 28 and 42 DOA; however, lipolysis based on per gram adipose tissue was increased (P < .05) with the addition of isoproterenol and theophylline for the restricted broilers compared to the full-fed broilers at 28 DOA. No difference was observed between the feed regimens at 42 DOA with hormone addition. Lipogenesis of the restricted broilers was lower (P < .05) than that of the full-fed broilers at 14 and 56 DOA. No difference in glucose oxidation was found between chickens fed the two regimens. Reduced abdominal fat in the restricted broilers is attributed to the reduction of adipocyte volume, which may be due to decreased lipogenesis.

Effect of sera from lean and obese pigs on the differentiation of porcine adipose stromal-vascular cells in culture

Primary cultures of stromal-vascular (S-V) cells from adipose tissue of new-born pigs were used to evaluate the characteristics of four sera obtained from male and female genetically lean or obese pigs weighing 50-60 kg. (2) Lean pig sera (LPS) stimulated greater levels of sn-glycerol-3-phosphate dehydrogenase (GPDH) activity in cultured cells than obese sera (OPS). Male LPS tended to promote higher GPDH specific activity than female LPS or male and female OPS. When GPDH was expressed on a per DNA basis, male LPS significantly (P < 0.05) increased GPDH per unit DNA compared with female LPS or male and female OPS.

Effect of age on the differentiation of porcine adipose stromal-vascular cells in culture

Stromal-vascular (S-V) cells isolated from adipose tissue of newborn pigs (NBPC) and mature pigs (MPC) by collagenase digestion were used to evaluate differences in preadipocyte culture and development. Cells were seeded at a density of 3 x 10(4) cells/cm2 on six-well (35-mm) tissue culture plates in 3 mL of DMEM/HAM's F12 medium plus 10% fetal calf serum and cultured at 37 degrees C under a humidified atmosphere of 95% air:5% CO2 for 24 h. Cells were then washed thoroughly in DMEM/HAM's F12 medium without fetal calf serum and maintained in serum free (SF) medium or SF medium supplemented with 2.5% newborn pig serum (NBPS) or mature pig serum (MPS) for 12 d. After 1 d, more NBPC adhered to the culture plates, as indicated by DNA values. After 12 d, protein per culture well was not significantly different, but DNA concentration per well remained higher (P < .05) in cultures of NBPC than in the MPC cultured in the same medium, indicating fewer MPC. Protein:DNA ratios were higher (P < .05) in cultures of MPC regardless of the medium, reflecting larger cell size. More cells containing fat deposits were seen with NBPC in all conditions in comparison with MPC, and more fat was deposited in NBPC in SF than in SF plus NBPS or MPS. The NBPC had higher (P < .05) sn-glycerol-3-phosphate dehydrogenase (GPDH; EC 1.1.1.8) per protein than MPC regardless of the medium. For both cell types, GPDH activity in either serum was less than activity of cells grown in SF.(ABSTRACT TRUNCATED AT 250 WORDS)

HLA-DQB1 codon 57 and IDDM in Chinese living in Taiwan

OBJECTIVE

To study the human leukocyte antigen (HLA)-DQB1 genetic background in the Chinese population in Taiwan and its association with the low incidence of insulin-dependent diabetes mellitus (IDDM) in this population.

RESEARCH DESIGN AND METHODS

Forty-eight IDDM patients and 59 nondiabetic unrelated control subjects were recruited from the population in Taiwan. HLA-DQB1 exon 2 was enzymatically amplified by polymerase chain reaction. HLA-DQB1 alleles were diagnosed by dot blotting and hybridization with 16 sequence-specific oligonucleotide probes.

RESULTS

DQB1*0201 and DQB1*0302 alleles were more frequent and DQB1*0301 and DQB1*0601 were less frequent in Chinese with IDDM than in control subjects. Genotypes for homozygous non-aspartic acid residue (NA/NA) at position 57 were positively associated with IDDM at a relative risk of 4.34 (P < 0.001), and those for homozygous aspartic acid (A/A) were negatively associated with IDDM at a relative risk of 0.14 (P < 0.001). Among the NA/A heterozygotes, only DQB1*0201/DQB1*0303 was significantly increased in IDDM subjects.

CONCLUSIONS

The amino acid residue at position 57 of HLA-DQ beta-chain is significantly associated with the development or prevention of IDDM in Chinese subjects living in Taiwan. Other genetic and environmental factors may also play important roles in pathogenesis of IDDM.