Induced oxidative stress and cell death in the A549 lung adenocarcinoma cell line by ionizing radiation is enhanced by supplementation with docosahexaenoic acid.

Both ionizing radiation and docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid (PUFA), have been shown to inhibit tumor cell growth at least in part by increasing oxidative stress. In this study, the effects of ionizing radiation, DHA, or a combination of the two on cell proliferation, anchorage-independent growth, apoptosis, and lipid peroxidation in A549 lung adenocarcinoma cells were examined. In this study, significant decreases in cell proliferation and colony formation were noted for ionizing radiation or DHA treatments, whereas a combination of the two showed significant reductions over either treatment alone. Conversely, lipid peroxidation and apoptotic cell death showed significant increases with ionizing radiation and DHA treatments, whereas cells receiving both treatments demonstrated further significant increases. Moreover, addition of vitamin E, an antioxidant, was able to completely reverse lipid peroxidation and cell death due to ionizing radiation and partially reverse these changes in DHA treatments. Finally, the preferential incorporation of DHA into lung and xenograft compared to liver tissue is demonstrated in an in vivo model. These findings confirm the potential of DHA supplementation to enhance the treatment of lung cancer using ionizing radiation by increasing oxidative stress and enhancing tumor cell death.

Influence of PvuII (intron 6) polymorphism of the lipoprotein lipase gene on cord plasma lipid and apolipoprotein levels in Indian and Chinese newborns of Singapore.

The influence of the PvuII polymorphism (intron 6) of the lipoprotein lipase (LPL) gene on cord plasma lipid traits was studied in 252 ethnic Chinese and 240 ethnic Indian newborns of Singapore. The allelic frequencies of P+ (presence of the restriction site) were 0.67 and 0.56 in the Chinese and Indian newborns, respectively, similar to their respective adult populations. The genotype distributions at the PvuII site were at Hardy Weinberg equilibrium in both ethnic Chinese (chi2 = 2.0) and ethnic Indians (chi2 = 3.6). Cord blood HDL-cholesterol (HDL-C) levels are higher in newborn Chinese than newborn Indians. In addition, cord blood LDL-cholesterol (LDL-C), apoB, and lipoprotein(a) levels are lower in newborn Chinese than newborn Indians. Both newborn Chinese and Indian male homozygotes for P- allele have higher cord blood LDL-C levels than newborns with the more common P+P+ or P-P+ genotypes. In Chinese male newborns, the LDL-C levels were 0.76 +/- 0.61 mmol/L, 0.53 +/- 0.29 mmol/L and 0.46 +/- 0.25 mmol/L, respectively (p = 0.01). In Indian male newborns, the LDL-C levels were 0.88 +/- 0.35 mmol/L for the P-P- genotype and 0.65 +/- 0.24 mmol/L for the P+P+ genotype (p = 0.003). In addition, the influence of the P- allele on LDL-C levels is remarkably similar in both ethnic groups, accounting for 8.48% of the population variance in the Chinese newborns and 8.09% in the Indian newborns. In contrast, no obvious effect of genotype is seen in this lipid parameter in the newborn females of either ethnic groups. There is presence of significant genotype specific influence on the LDL-C levels in cord plasma in male newborns, suggesting an early expression of the LPL gene locus.

Malignant eccrine spiradenoma. Case report and review of the literature.

Malignant eccrine spiradenoma is an exceedingly rare tumor. A case of a 72-year-old women with this highly aggressive malignancy arising from a long-standing lower leg lesion is reported. Management during the course of disease included surgery, radiation therapy (RT), hyperthermic limb perfusion chemotherapy, and chemotherapy. The patient died of her disease, with widespread metastatic disease 20 months after the diagnosis. A review of the literature is presented, and treatment considerations are summarized.

Plasma lipids and lipoprotein(a) levels in the Chinese from China and Singapore.

This study compared the influence of environmental factors on plasma lipid levels between the descendants of immigrant southern Han Chinese (Singapore Chinese, n = 275) and the native Chinese from southern China (n = 277). Their lipid profiles including lipoprotein (a) [Lp(a)] were measured and compared. The alpha level was set at 0.05 throughout the analysis. Body mass index (BMI), plasma total cholesterol (TC), low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC) and triglycerides (TG) levels were significantly elevated in the Singapore Chinese. Plasma Lp(a) however, was comparable in both groups for concentrations as well as frequency distributions. Since both groups were genetically identical, the similar Lp(a) level was in agreement with studies which reported that the apolipoprotein(a) [apo(a)] gene explained as much as 70% of the plasma Lp(a) variations in Chinese. No correlation of plasma Lp(a) level was observed with age and BMI while significant positive linear correlations were observed with TC and LDLC in the male subjects only. We concluded that environmental factors (possibly affluent lifestyle and westernised diet) have significantly influenced the lipid risk factor levels of the Singapore Chinese whereas Lp(a) levels, which are predominantly under genetic control, were not altered significantly.

Transcatheter embolization of coronary artery fistula with controlled release coils.

The treatment for large congenital coronary cameral fistulas has been surgical but with advances in interventional catheterization techniques transcatheter embolization of these fistulas with coils or detachable balloons is now possible. This report describes occlusion of a congenital coronary arteriovenous fistula in a 6-year-old girl.

Ethnic variation of cord plasma apolipoprotein levels in relation to coronary risk level: a study in three ethnic groups of Singapore.

In multiracial Singapore, the prevalence of coronary artery disease is highest in ethnic Indian and lowest in ethnic Chinese populations. Since susceptibility to coronary artery disease is closely associated with plasma lipid traits, we studied the cord blood lipid and apolipoprotein profiles of the three ethnic groups in Singapore to determine if ethnic differences in lipid profile are present at birth. The high-risk lipid traits of high LDL-cholesterol, triglycerides and apo B, low HDL-cholesterol and apo A-I were found to be highest in ethnic Indian and lowest in ethnic Chinese populations. This difference was concordant with the relative coronary mortality rates for their respective adult populations in Singapore.

Racial variation of cord plasma lipoprotein(a) levels in relation to coronary risk level: a study in three ethnic groups in Singapore.

Lipoprotein(a) [Lp(a)] is recognized as an independent risk factor for atherosclerosis. Studies have also shown that there are racial differences in the Lp(a) profile. The multiracial population of Singapore has demonstrated a differential prevalence of coronary artery disease, which is concordant with the plasma Lp(a) profile in the adult populations of Singapore. The level of Lp(a) is under strict genetic control, and its plasma concentration is determined significantly by inheritance. Expression of the racial profile of Lp(a) at birth was studied in the cord blood of 542 male and 468 female newborns from three ethnic groups of Singapore using the sandwich-ELISA. The Lp(a) levels were then related to the coronary risk levels of their respective adult populations. Lp(a) levels in Singapore newborns were found to be independent of the infant's birth weight and sex but were significantly influenced by race. Indian newborns had significantly higher plasma levels of Lp(a). Chinese newborns had the lowest Lp(a) levels at birth. The ranking of Lp(a) levels at birth was concordant with the relative coronary mortality rates for the respective adult populations of Singapore. Racial differences in plasma Lp(a) levels are present and expressed at birth.

Lack of association of angiotensin-converting enzyme (ACE). Gene insertion/deletion polymorphism with CAD in two Asian populations.

Association of the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) gene with coronary artery disease with or without myocardial infarction (MI) was examined in a group of Chinese and Indian men in Singapore. The sample comprised an angiographically confirmed patient group of 276 Chinese and 102 Indians, of which 155 Chinese and 72 Indians had MI, and a matched healthy control group (147 Chinese and 166 Indians). The frequency of the D allele in the Chinese was 0.39 in those with CAD with MI, 0.43 in those with CAD but without MI, and 0.41 in the control group. The frequency of the D allele in Indians was 0.44 in CAD with or without MI, and 0.45 in the control group. There was no significant association of the ACE gene with CAD or MI in the Chinese or Indians, either in the entire sample or in different risk groups. The frequency of the D allele was significantly lower in the healthy Chinese and Indians than that reported in Caucasians. The association of the ACE gene with MI or CAD observed in other studies could not be confirmed in the present series of Chinese and Indians in Singapore.

T cell receptor beta chain RFLP in Chinese, Indians and Malays from Singapore.

Restriction fragment length polymorphism (RFLP) of the gene encoding the beta chain of the human T cell receptor (TcR) was studied in three ethnic groups in Singapore by Southern blotting. Polymorphism in the beta chain gene was identified in BglII-digested DNA samples using a 770-bp TcR beta cDNA clone containing the joining and constant region segments. The TcR beta/BglII polymorphism was studied in 136 Chinese, 93 Indian and 88 Malay samples. The frequency of the less frequent allele (TcR beta*2) in all the ethnic groups was significantly lower (0.15-0.29, p < 0.01) than that in the Caucasians (0.46). Indians had a significantly lower frequency of this allele (0.15) than the Chinese (0.29) and Malays (0.26).

Glucose-6-phosphate dehydrogenase deficiency in Singapore.

Glucose-6-phosphate dehydrogenase (G6PD) in man is an X-linked enzyme. The deficiency of this enzyme is one of the most common inherited metabolic disorders in man. In Singapore, three clinical syndromes associated with G6PD deficiency had been described: severe haemolysis in neonates with kernicterus, haemoglobinuria and "viral hepatitis"-like syndrome. The human G6PD monomer consists of 515 amino acids. Only the tetrameric or dimeric forms composed of a single type subunit are catylitically active. The complete amino acid sequence of G6PD had been elucidated in man and various other animals. The region of high homology among the enzymes of various animals is presumably functionally active. Among the Chinese in Singapore, three common molecular variants had been identified: Canton (nt 1376 G --> T), Kaiping (nt 1388 G --> A) and Mediterranean (nt 563 C --> T) in frequencies of 24%, 21% and 10% respectively. In addition, two common mutants (Gaozhou, nt 95 A --> G and Chinese 5, nt 1024 C --> T) have been detected in Singapore Chinese in low frequencies. In Malays, 6 different deficient variants are known in Singapore (3 new, 1 Mahidol, 1 Indonesian and 1 Mediterranean).

Molecular diagnosis of Duchenne muscular dystrophy in Singapore.

Duchenne muscular dystrophy (DMD) is a common lethal sex-linked recessive disorder. Seventy percent of the cases are inherited and 30% are due to mutations. The mainstay of prevention is detection of female carriers and antenatal diagnosis of affected foetuses. Before the era of molecular diagnosis, DMD has been clinically defined. Serum creatine kinase (CK) has also been used to screen women at risk for carrier status. With the isolation and sequencing of the DMD gene at Xp21 and the identification of the DMD gene-product dystrophin, DNA technology can be applied for the diagnosis of the affected, for the detection of carriers and in antenatal diagnosis. The multiplex polymerase chain reaction (PCR) technique offers a rapid and simple screening method for deletions of the gene. We were able to detect partial deletions which account for 58.3% of gene defects in our patients. This direct demonstration of the gene defect that causes DMD gives a 100% assurance of accuracy and specificity of the diagnosis. Linkage analysis is especially useful for prenatal diagnosis and carrier detection in the remaining 41.7% of families without detectable deletions or duplications. This approach however is indirect and is dependent on information on genotypes from affected males and key family members. With the availability of increasingly more restriction fragment length polymorphisms (RFLPs), it has become practical to use the haplotype method for accurate carrier detection and prenatal diagnosis.

Five restriction fragment length polymorphisms of the APOA1-C3 gene and their influence on lipids and apolipoproteins in healthy Chinese.

The distribution of five restriction fragment length polymorphisms (RFLPs) of the APOA1-C3 gene cluster and their influence on serum lipids and apolipoprotein levels was investigated in 151 healthy Chinese of both sexes. The frequencies of the rare alleles at ApaI, BanI, XmnI (A1) and SstI (C3) sites were significantly different in the Chinese when compared to Caucasians as follows: ApaI: 0.25 vs. 0.42 (p < 0.02); BanI: 0.33 vs. 0.16 (p < 0.01); XmnI: X2, 0.30 vs. 0.14, and X3, 0.08 vs 0.05 (p = 0.001); SstI (C3): 0.23 vs. 0.12 (p = 0.011). The frequency of P2 (PstI) at 0.04 was similar to that in Caucasians (0.07). The distribution of the genotypes of all the RFLPs was in Hardy-Weinberg equilibrium in this population. A significant association of the SstI polymorphism of the C3 region with the serum high-density lipoprotein (HDL)-cholesterol level was observed in both men and women, the rarer allele (S2) being associated with higher levels (p < 0.05). 5.8% of the sample variance of the HDL-cholesterol level in this sample could be explained by the SstI polymorphism of the C3 region (F = 6.07, p = 0.003). The association of the SstI locus with serum HDL-cholesterol was stronger in males than in females (R2 = 13.8 and 6.7%, respectively). There was a similar trend of association of the serum apolipoprotein A-I level with the SstI polymorphism, though it did not reach statistical significance. There was no association between the levels of any of the lipid and apolipoproteins studied with RFLPs of the APOA1 gene.

Molecular variants of red cell glucose-6-phosphate dehydrogenase deficiency in Central Java, Indonesia.

One hundred and sixty-nine Javanese males were screened for the presence of red cell glucose-6-phosphate dehydrogenase (G6PD) variants by a dye decoloration screening test and starch gel electrophoresis. The frequency of G6PD deficiency was 14%. Three non-deficient electrophoretic variants with mobilities of 95, 105 and 107% of GdB+ were encountered. Sixteen G6PD-deficient subjects were further investigated for the presence of mutations at nt95 A-->G, nt487 G-->A, nt493 A-->G, nt563 C-->T, nt1024 C-->T, nt1376 G-->T, nt1388 G-->A and the silent mutation (nt1311 C-->T) of the G6PD gene by natural or artificially created amplified restriction sites. They were identified by the polymerase chain reaction and electrophoresis of restriction-digested products. Five subjects had the Mediterranean mutation (nt563 C-->T), but only one had simultaneous presence of nt1311(T). The next common mutations were 1376(T) in three subjects and 487(A) in two subjects. Five of the sixteen subjects had the nt1311(T) mutation giving an overall frequency of 0.31. The other four mutations were absent in this population sample.

Molecular genetics of Wilms' tumour.

Wilms' tumour, or nephroblastoma, is an embryonal malignancy of the kidney with an incidence of approximately 1 in 10,000 live births. It occurs in both sporadic and familial forms, but only 1% of Wilms' tumour patients have a positive family history. The molecular genetics of Wilms' tumour have been the subject of extensive research and at least three genes (WT1, WT2, WT3) have been implicated. WT1 has been mapped to 11p13, and it has been suggested that loss or inactivation of a tumour-suppressor gene at 11p13 might be a primary event in the development of Wilms' tumour. The WT2 gene maps to 11p15 in the region of the Beckwith-Wiedemann locus. The WT3 locus is likely to be located to chromosome 16q. The understanding of the molecular genetics of Wilms' tumour is reviewed briefly.

Biochemical characteristics of four common molecular variants in glucose-6-phosphate dehydrogenase-deficient Chinese in Singapore.

Biochemical characteristics were determined for four common molecular variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency and 10 non-deficient Chinese males in Singapore. The variants included one Mediterranean (nt563 C-->T), two Canton (G-->T at nt1376) and one each of Kaiping (1388 G-->A) and Chinese-5 (1024 C-->T) variants. Molecular identification was carried out by amplication of genomic DNA with specific oligonucleotide primers followed by digestion with restriction enzymes that recognize artificially created or naturally occurring restriction sites. All the variants had low enzyme activity in red cells (0.2-0.6 IU/g Hb). All but the Chinese-5 variant (nt1024) had a normal Km for NADP (7-10 microM). The Mediterranean variant had a high utilization of deamino-NADP (296%), followed by the Canton variant 1376 substitution (131%). The Km for glucose-6-phosphate was low in the Mediterranean and 1376 variant (18-40 microM) but high in the 1024 substitution (104 microM). Electrophoretic mobility in TEB buffer (pH 8.6) was slightly faster (103%) for the 1376 mutation while 100% for all the others. All but the 1024 substitution had increased analogue utilization for galactose-6-phosphate and 2-deoxy-glucose-6-phosphate (58 and 68% for the Mediterranean mutation and 14-23% for the 1376 and 1388 substitutions, respectively), and reduced heat stability.

Lack of association of apolipoprotein E polymorphism with plasma Lp(a) levels in the Chinese.

Apolipoprotein E (apoE) polymorphism and its influence on plasma lipids, lipoproteins, lipoprotein (a) [Lp(a)] and apolipoproteins was studied in 536 (270 males and 266 females) healthy Chinese in Singapore. From analysis of variance with age and BMI as covariates, apoE genotype was found to exert a significant influence on plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and apoB in females. Its effect in males was marginally significant only on LDL-C. In both sexes, plasma TC, LDL-C and apoB were lower in those who were E2-3 than in those who were E3-3. There was no significant difference in log-transformed Lp(a) level between the apoE genotypes after adjusting for the confounding effect of LDL-C in addition to age and BMI. The percentage variance (R2 x 100) of the lipid traits explained by apoE polymorphism in the females was 4.94% for plasma TC, 5.85% for LDL-C and 4.25% for apoB. We conclude that: 1) epsilon 2 allele had a lowering effect on plasma TC, LDL-C and apoB; 2) apoE polymorphism did not have any significant influence on Lp(a) concentration; and 3) the effect of apoE polymorphism on plasma TC, LDL-C and apoB was gender-specific, with a stronger influence in females than in males.

Racial variation of factor VII activity and antigen levels and their correlates in healthy Chinese and Indians at low and high risk for coronary artery disease.

Plasma factor VII activity (FVIIc) is one of the independent risk factors of coronary artery disease (CAD) and is controlled by both genetic and environmental factors. South Asians including Indians have one of the highest prevalence and mortality rates from CAD while the Chinese have a much lower risk. Generally accepted risk factors cannot explain the high mortality from CAD in Indians. We examined two hundred and seventy seven Chinese (124 m, 153 f); and 216 healthy Indian (150 m, 66 f) adults for serum lipids; plasma FVIIc and FVIIag levels in order to examine racial variations of these and their correlates in these two populations. Both Indian men and women had significantly higher FVIIc levels (12% and 11%, respectively) than the Chinese even after adjustments of age, BMI and lipids (P < 0.01). In contrast, Indians had significantly lower plasma FVIIag levels than Chinese (8% and 9%, respectively in men and women; P < 0.01). Multiple linear regression analysis shows a strong correlation of FVIIc with serum triglycerides accounting for 4-8% of the total variability of FVIIc in different groups. Further, there was a stronger correlation between FVIIc and FVIIag in Indians than that in the Chinese (0.43 vs. 25) suggesting a greater activation resulting in higher FVIIc in Indians inspite of lower FVIIag levels. The higher FVIIc and stronger activation by triglycerides observed in this study partly explain the higher risk of CAD in Indians.

Linkage disequilibrium between two loci (5' untranslated exon 1 and intron 5-DdeI) of the antithrombin III gene in three ethnic groups in Singapore.

The distribution of two common DNA polymorphisms (5' untranslated exon 1 and intron 5-DdeI) of the antithrombin III (ATIII) gene was studied in three ethnic groups in Singapore: 251 Chinese, 221 Dravidian Indians and 102 Malays. The polymorphisms were identified by the polymerase chain reaction and size fractionation in agarose gels. The 5' untranslated to exon 1 polymorphism is a length polymorphism while the intron 5 polymorphism is a restriction site (DdeI) polymorphism. The frequency of the short fragment (S) of the 5' to exon 1 length polymorphism of the ATIII gene was found to be 0.37 in the Chinese, 0.54 in the Malays and 0.65 in the Dravidian Indians. For the Chinese, this was significantly lower compared to the Caucasians and Indians (p < 0.0001) and the Malays (p < 0.01). On the other hand, the frequencies of DdeI+ did not vary significantly among these three populations (p > 0.05). The distribution of different genotypes at these two loci of the ATIII gene was in Hardy-Weinberg equilibrium in all three ethnic groups. A strong linkage disequilibrium between these two polymorphisms was observed in all the ethnic groups and the estimated correlation coefficient (delta) was 0.42 in the Chinese (p < 0.001), 0.61 in the Dravidian Indians (p < 0.001) and 0.43 in the Malays (p < 0.001). The frequencies of haplotype S+, L+ and L- were, respectively, 0.37, 0.40 and 0.23 in the Chinese, 0.65, 0.18 and 0.16 in the Dravidian Indians and 0.54, 0.37 and 0.09 in the Malays.(ABSTRACT TRUNCATED AT 250 WORDS)

Population genetic study among the Orange Asli (Semai Senoi) of Malaysia: Malayan aborigines.

A population genetic study was undertaken to provide gene frequency data on the additional blood genetic markers in the Semai and to estimate the genetic relations between the Semai and their neighboring and linguistically related populations by genetic distance and principal components analyses. Altogether 10 polymorphic and 7 monomorphic blood genetic markers (plasma proteins and red cell enzymes) were studied in a group of 349 Senoi Semai from 11 aboriginal settlements (villages) in the Pahang State of western Malaysia. Both the red cell glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (PGD) loci reveal the presence of polymorphic frequencies of a nondeficient slow allele at the G6PD locus and a fast allele at the PGD locus. The Semai are characterized by high prevalences of ahaptoglobinemia and G6PD deficiency, high frequencies of HP*1, HB*E, RH*R1, ACP*C, GLO1*1, PGM1*2+, and GC*1F and corresponding low frequencies of ABO*A, HbCoSp, HB*B0, TF*D, CHI, and GC*2. Genetic distance analyses by both cluster and principal components models were performed between the Semai and 14 other populations (Malay; Javanese; Khmer; Veddah; Tamils of Malaysia, Sri Lanka, and India; Sinhalese; Oraon; Toda and Irula of India; Chinese; Japanese; Koreans) on the basis of 30 alleles at 7 polymorphic loci. A more detailed analysis using 53 alleles at 13 polymorphic loci with 10 populations was carried out. Both analyses give genetic evidence of a close relationship between the Semai and the Khmer of Cambodia. Furthermore, the Semai are more closely related to the Javanese than to their close neighbors--the Malay, Chinese, and Tamil Indians. There is no evidence for close genetic relationship between the Semai and the Veddah or other Indian tribes. The evidence fits well with the linguistic relationship of the Semai with the Mon-Khmer branch of the Austro-Asiatic language family.

Inflammatory response in bacterial meningitis: cytokine levels in the cerebrospinal fluid.

Inflammatory response plays an important role in the pathogenesis of cerebral injury in bacterial meningitis. In this study, we evaluated the cytokine levels of interleukin 1-beta (IL1 beta), tumour necrosis factor alpha (TNF alpha) and interleukin 6 (IL6) in the cerebrospinal fluid (CSF), and determined their correlation with acute clinical complications and with changes in CSF biochemistry. Interleukin 6, TNF alpha and IL1 beta were present in 9/9, 3/9 and 4/9 patients, respectively. The CSFs with detectable TNF alpha or IL1 beta had higher levels of IL6 (p < 0.02), protein (NS) and lower glucose levels (p < 0.02), compared with those in which TNF alpha and IL1 beta were absent. Tumour necrosis factor alpha and IL1 beta levels also correlated with the presence of prolonged fever, fits, spasticity and death (logTNF alpha: r = 0.70, p < 0.05; logIL1 beta: r = 0.62, p = 0.08). The cytokine levels reflect the degree of inflammatory response and are positively correlated with the severity of acute clinical complications. Modulation of this inflammatory response in bacterial meningitis may improve its morbidity and mortality.