Pharmacological evidence for an abstinence-induced switch in 5-HT1B receptor modulation of cocaine self-administration and cocaine-seeking behavior.

Studies examining serotonin-1B (5-HT1B) receptor manipulations on cocaine self-administration and cocaine-seeking behavior initially seemed discrepant. However, we recently suggested based on viral-mediated 5-HT1B-receptor gene transfer that the discrepancies are likely due to differences in the length of abstinence from cocaine prior to testing. To further validate our findings pharmacologically, we examined the effects of the selective 5-HT1B receptor agonist CP 94,253 (5.6 mg/kg, s.c.) on cocaine self-administration during maintenance and after a period of protracted abstinence with or without daily extinction training. We also examined agonist effects on cocaine-seeking behavior at different time points during abstinence. During maintenance, CP 94,253 shifted the cocaine self-administration dose-effect function on an FR5 schedule of reinforcement to the left, whereas following 21 days of abstinence CP 94,253 downshifted the function and also decreased responding on a progressive ratio schedule of reinforcement regardless of extinction history. CP 94,253 also attenuated cue-elicited and cocaine-primed drug-seeking behavior following 5 days, but not 1 day, of forced abstinence. The attenuating effects of CP 94,253 on the descending limb of the cocaine dose-effect function were blocked by the selective 5-HT1B receptor antagonist SB 224289 (5 mg/kg, i.p.) at both time points, indicating 5-HT1B receptor mediation. The results support a switch in 5-HT1B receptor modulation of cocaine reinforcement from facilitatory during self-administration maintenance to inhibitory during protracted abstinence. These findings suggest that the 5-HT1B receptor may be a novel target for developing medication for treating cocaine dependence.

The prevalence of platelet activating factor acetylhydrolase single nucleotide polymorphisms in relationship to necrotizing enterocolitis in Northwest Louisiana infants.

PURPOSE: Studies documented that platelet activating factor (PAF) and the enzyme platelet activating factor acetylhydrolase (PAFAH) play a very important role in the pathogenesis of neonatal necrotizing enterocolitis (NEC). In this retrospective, case-controlled pilot study, the authors investigated the prevalence of single nucleotide polymorphisms (Ile198Thr and Ala379Val) of the PAFAH gene. SUBJECTS AND METHODS: We screened 570 blood samples from both Caucasian and African-American preterm infants in the Northwest Louisiana population for the above mentioned PAFAH gene polymorphisms. Out of 570 infants, 36 had stage I or II NEC based on diagnostic coding, the International Classification of Diseases, 9th revision, Clinical Modification, 2009 (ICD-9-CM). The remaining infants without an ICD-9-CM diagnosis of NEC were recruited as control population. The DNA was isolated and restriction fragment length polymorphism microplate polymerase chain reaction assay was performed. RESULTS: Variants of the PAFAH gene polymorphism (Ile198Thr and Ala379Val) frequencies were not significantly different between the infants with NEC and the control group (P value of 0.26 by either multiple logistic regression analysis or the Cochran-Mantel-Haenszel test). CONCLUSIONS: This is the first study of its kind in exploring the relationship between NEC and single nucleotide polymorphisms in the coding genes of the enzyme PAFAH. Our preliminary data demonstrated that adjusted for the effect of race, PAFAH polymorphisms (Ile198Thr and Ala379Val) have no significant effect on NEC.

Endothelial nitric oxide synthase genotypes in the etiology of retinopathy of prematurity in premature infants.

PURPOSE: Retinopathy of Prematurity (ROP) is a vasoproliferative disorder affecting preterm infants leading to visual impairment. ROP is more common in Caucasians than African Americans. Very low birth weight infants have immature retinas and are susceptible to ROP. Because of differences in individual responses to the treatment, various genetic factors have been looked into to understand the etiology of ROP. Endothelial nitric oxide (eNO) serves as a vasodilator, relaxes smooth muscle, prevents platelet aggregation, and facilitates improved blood flow and vascular tonicity. Mutant eNO synthase (eNOS) genotypes result in reduced nitric oxide levels by decreasing enzyme activity. Since eNO affects vasculature and ROP is a vascular disease, the present investigation was aimed at studying the association of genotypes with ROP. METHODS: Two eNOS gene single nucleotide polymorphisms (SNPs) (T-786C, and G894T) were studied by microplate-Restriction Fragment Length Polymorphism Polymerase Chain Reaction (RFLP PCR) method. Genotypes were studied in 146 premature infants. RESULTS: The present data showed significant differences in the baseline gene frequencies between Caucasians and African Americans. ROP patients displayed 3-fold higher frequencies of mutant -786C and 894T alleles in both ethnicities compared to respective controls. CONCLUSIONS: The present data suggest ethnic stratification of genotypes. Mutant -786C and 894T alleles are significant risk factors in the development of ROP, and suggest a strong association between eNOS polymorphisms and the disease. It is interesting to know if a larger dataset of ROP patients can confirm our initial findings.

Is an endothelial nitric oxide synthase gene mutation a risk factor in the origin of intraventricular hemorrhage?

OBJECT: Studies have shown decreased levels of nitric oxide (NO), the product of endothelial NO synthase (eNOS) gene activity, in infants with respiratory conditions and intraventricular hemorrhage (IVH). The authors evaluated the association of the eNOS gene promoter polymorphism T-786C with the cause of these conditions (respiratory conditions and IVH) in premature infants. METHODS: Blood samples from 124 African American premature infants were studied. The DNA was isolated and microplate polymerase chain reaction-restriction fragment length polymorphism assay was performed. Genotypes were scored as: TT homozygotes with 140 bp and 40 bp; CC homozygotes with 90 bp, 50 bp, and 40 bp; and TC heterozygotes with 140 bp, 90 bp, 50 bp, and 40 bp. Genotypes were stratified according to ethnicity, preterm status, and prematurity conditions. RESULTS: The mutant allele -786C was present in 15.3% of premature infants with respiratory distress syndrome, bronchopulmonary dysplasia, and IVH, compared with 7.25% in those premature infants without these conditions. A significant 2-fold increase of the mutant allele in patients compared with controls (p = 0.04, OR 2.3) reveals that the eNOS -786C allele could be a significant risk factor in the origin of respiratory conditions and IVH in premature infants. CONCLUSIONS: These results suggest that the mutant eNOS -786C allele is a significant risk factor in the origin of respiratory and IVH diseases, probably mediating an insufficient supply of endogenous NO in premature infants.

The effect of maternal and cord-blood vitamin C, vitamin E and lipid peroxide levels on newborn birth weight.

Background Newborn birth weight has been shown to significantly correlate with the blood levels of vitamin C. Objective This study was planned to answer the question of why vitamin C levels correlate with birth weight; does such correlation reflect a protective effect of vitamin C on fetal growth, by its antioxidant characteristics or does it correspond to the nutritional status of both the mother and the fetus. We examined the hypothesis that maternal blood levels of vitamin C, but not vitamin E influence newborn birth weight. We determined maternal and newborn blood levels of vitamin C, vitamin E, and lipid peroxides (an index of oxidative insult) and the birth weights of full-term newborns delivered at our hospital. Results Compared with maternal blood levels, newborns have higher levels of vitamin C and lipid peroxides, but lower levels of vitamin E. There was a significant correlation in levels between mothers and their newborns for blood levels of vitamin C (r = 0.82, P < 0.01) and vitamin E (r = 0.61, P < 0.02) but not for lipid peroxides (r = 0.001). This suggests that maternal vitamin C and vitamin E intake can influence fetal vitamin C and vitamin E levels. Linear regression analysis shows a significant positive relationship between newborn birth weight and maternal plasma vitamin C (r = 0.51, P < 0.02). Similarly, there was a modest but significant positive relationship between newborn birth weights and newborn vitamin C levels (r = 0.61, P < 0.05). However, there was no relationship between maternal or fetal vitamin E or lipid peroxides levels and the newborn birth weight. Conclusions This study with a small number of subjects suggests a significant association between newborn birth weight and maternal and newborn plasma vitamin C levels. Lack of relationship between birth weight and vitamin E and lipid peroxides suggest that antioxidant function of vitamin C does not appear to have a major role in the effect of vitamin C on birth weight.

IL-10, IL-6 and CD14 polymorphisms and sepsis outcome in ventilated very low birth weight infants.

BACKGROUND: Genetic variation in the innate immune system of the host may play a role in determining the risk of developing infection, as well as outcome from infection. METHODS: Infectious complications were retrospectively determined in 293 (233 African-American (AA), 57 Caucasian and 3 Hispanic) mechanically ventilated very low birth weight (VLBW) infants (<1500 grams at birth) who were genotyped for the IL-6 -174 G/C, IL-10 -1082 G/A and CD14 -260 C/T single nucleotide polymorphisms (SNPs). RESULTS: The IL-6 -174C allele was associated with an increased incidence of late blood stream infection (BSI) in AA but not Caucasian infants. In AA infants with the C allele the incidence of late BSI was 20/29 (69%) compared to 94/204 (46%) in homozygous GG infants (RR 2.6, 95% CI: 1.1-6.0, p = 0.021). The IL-10 -1082A allele was associated with an increased incidence of late BSI. One or more episodes of late BSI developed in 14 (35%) of 40 infants with the GG genotype, 71 (49%) of 145 infants with the GA genotype and 63 (58%) of 108 infants with the AA genotype (p = 0.036). Infants with the A allele (AA or GA genotypes) had an incidence of late BSI that was 134/253 (53%) compared to 14/40 (35%) in homozygous GG infants (RR 2.1, 95% CI: 1.04-4.19, p = 0.035). The CD14 -260 C/T SNP did not alter the overall risk for BSI in ventilated VLBW infants. Multiple BSI episodes were more common in the TT genotype group (CC: 17%, CT: 11%, TT: 30%, p = 0.022). This effect was due to the strong effect of the TT genotype on the incidence of multiple BSI in AA infants (CC: 15%, CT: 11%, TT: 39%, p = 0.003). CONCLUSION: The IL-6 -174 G/C, IL-10 -1082 G/A and CD14 -260 C/T SNPs may alter risk for BSI in ventilated VLBW infants.

Thiamin deficiency: a possible major cause of some tumors? (review).

Based solely on clinical clues from a malnourished population, thiamin alone was intentionally and successfully injected to human cases with some tumors or masses. Two cases of submandibular gland cyst and 13 out of 15 cases of Baker's cyst were cured without recurrence for several decades. In a case with pathology-confirmed osteosarcoma, subcutaneous perfusion of thiamin HCl 300 once only reduced its circumference from 30 to 20 cm, equivalent to a reduction of 50-75% in volume, within 2 days. Current concepts on the role of thiamin in carcinogenesis are controversial. Some authors claimed that thiamin supported high rate of tumor cell survival, proliferation and chemotherapy resistance and suggested anti-thiamin therapy for cancer. On the other hand, some investigators have reported evidence of prevention of several varieties of cancers by dietary thiamin. A limited number of animal studies revealed evident relationship between thiamin deficiency and cancer development. Therefore, further study on the mechanism switching thiamin between cancer supporter and suppressor is needed.

Novel allele of the endothelial nitric oxide synthase gene polymorphism in Caucasian asthmatics.

The purpose of the present study was to investigate an association of the endothelial nitric oxide synthase (eNOS) gene polymorphism with asthma. eNOS intron4 variable number of tandem repeats (27 bp repeats) genotypes were determined in asthma patients and control subjects using microplate PCR. The Caucasian Asthma patients displayed three alleles while Caucasian controls displayed only two alleles. However, African Americans displayed all three alleles in both asthma patients and controls. African American controls displayed significantly higher a allele, significantly lower b allele, as well as c allele than those in Caucasians. This was the first report to show that there was a novel eNOS genotype present in asthmatic patients but not in control subjects in the Caucasian Community. The novel allele which we termed the c allele, could be a significant risk factor in the etiology of asthma in Caucasians. This novel allele could be involved in higher levels of NO in our Caucasian asthmatics.

Association of IL-13, RANTES, and leukotriene C4 synthase gene promoter polymorphisms with asthma and/or atopy in African Americans.

PURPOSE: IL-13, RANTES (Regulated on Activation, Normal T cells Expressed and Secreted), and cysteinyl leukotrienes are asthma and atopy mediators. Two RANTES -403(G to A) and -28(C to G), an -1055 IL-13(C to T), and a -444(A to C) leukotriene C4 synthase (LTC4S) single nucleotide polymorphisms (SNPs) have been shown in Caucasians and Asians as asthma and atopy risk factors. We studied these SNPs in African Americans with asthma and/or atopy. METHODS: We studied 61 patients with asthma and/or atopy and 129 to 157 newborn controls for the -403 RANTES, -28 RANTES, and -1055 IL-13 SNPs, as well as 47 patients and 60 newborn controls for the -444 LTC4S SNP. RESULTS: The two groups did not significantly differ at the genotypes of the -403 and -28 RANTES SNP. On the other hand, the mutant TT genotype for the -1055 IL-13 SNP was detected in 19.7% of patients versus 12.7% in controls (P < 0.04, OR 2.9, 95% CI 1.0-8.0), and the mutant T allele in 58.3% versus 36.6% in controls (P < 0.02, OR 2.4, 95% CI 1.1-5.2). In a similar fashion, for the -444 LTC4S SNP, the mutant AC genotype was detected in 19.1% versus 10.0% in controls (P > 0.28); mutant C allele had an OR of 2.1 (95% CI 0.7-6.3). CONCLUSION: African American asthmatics/atopics had higher frequency of the TT mutant gene for the -1055 IL-13 SNP and of its mutant T allele. Regarding the -444 LTC4S SNP, there was a definite difference, although not statistically significant, with an OR of 2.1 for the mutant AC genotype in patients. If these findings become reproduced by larger studies, it may suggest that IL-13 and LTC4S SNPs can be used as predictive markers for asthma/atopy in African Americans.

Interleukin-10 -1082 G/A polymorphism and risk of death or bronchopulmonary dysplasia in ventilated very low birth weight infants.

IL-10 is an anti-inflammatory cytokine that may have a protective role in acute lung injury. IL-10 expression is affected by a single-nucleotide polymorphism (SNP) located at position -1082 (G to A). The A allele is associated with lower IL-10 production. Low IL-10 production has been linked to the development of BPD. Thus, the IL-10 -1082 SNP may be a genetic risk factor for the development of BPD in the premature newborn. The IL-10 -1082 SNP was determined in 294 (235 African American, 56 Caucasian, and 3 Hispanic) mechanically ventilated very low birth weight (VLBW) infants and compared to outcome (death and/or development of BPD). Differences in groups were analyzed using ANOVA (continuous variables) or chi square (proportions). The frequency of the A allele in our population was 0.62. Thirty-nine (13.3%) infants were homozygous GG, 146 (49.7%) were heterozygous GA, and 109 (37.0%) were homozygous AA. There were no significant differences between genotype groups with respect to ethnic origin, gender, need for surfactant replacement therapy, and isolation of Ureaplasma urealyticum or Mycoplasma hominis from tracheal aspirates at birth. However, AA infants were slightly more mature and of greater birth weight than GA infants (26.9 +/- 0.2 weeks vs. 26.3 +/- 0.2 weeks, P < 0.05, and 940 +/- 22 g vs. 882 +/- 18 g, P < 0.05, respectively). There was no significant effect of the IL-10 -1082 SNP on mortality or the development of BPD (O2 on 28 days or 36 weeks postconceptional age). However, when considered together, the IL-10 -1082 AA/GA genotypes (lower IL-10 production) were associated with a trend toward reduction in risk for the combined outcome of BPD or death (18/39 vs. 80/255, respectively; P = 0.068). The incidence of other complications of prematurity (retinopathy of prematurity, intraventricular hemorrhage, or periventricular leukomalacia) was not different between groups. In conclusion, the IL-10 -1082 G/A SNP does not have a major influence on mortality or the development of BPD in ventilated VLBW infants.

Angiotensin converting enzyme insertion/deletion polymorphism does not alter sepsis outcome in ventilated very low birth weight infants.

OBJECTIVE: This study compared the effect of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms on the incidence and outcome of sepsis in ventilated very low birth weight infants. STUDY DESIGN: Infectious complications were retrospectively determined in 295 (234 African-American, 58 Caucasian and three Hispanic) mechanically ventilated very low birth weight (VLBW) infants (<1500 g at birth) and compared ACE I/D genotype. RESULTS: The incidence of the D allele in the study population was 0.60. A total of 113 (38.3%) infants were homozygous DD, 128 (43.4%) were heterozygous ID and 54 (18.3%) were homozygous II. One or more episodes of late BSI developed in 28 (52%) of 54 infants with the II genotype, 66 (52%) of 128 infants with the ID genotype and 52 (46%) of 113 infants with the DD genotype (p=0.618). Neither the rates of non-CONS BSI (II: 24%, ID: 23%, DD: 22%; p=0.937) nor multiple bacteremic/fungemic episodes (II: 13%, ID: 16%, DD: 12%; p=0.641) were different between genotype groups. The ACE I/D polymorphism had no effect on sepsis-related mortality (II: 7%, ID: 5%, DD: 4%; p=0.692). Sepsis mortality for infants with late BSI was 14% in infants with the II genotype, 9% with the ID genotype and 10% with the DD genotype (p=0.764). CONCLUSIONS: The ACE I/D polymorphism does not have a significant effect on the incidence or outcome of sepsis in ventilated VLBW infants.

The Angiotensin Converting Enzyme Insertion/Deletion polymorphism is not associated with an increased risk of death or bronchopulmonary dysplasia in ventilated very low birth weight infants.

BACKGROUND: The ACE gene contains a polymorphism consisting of either the presence (insertion, I) or absence (deletion, D) of a 287 bp alu repeat in intron 16. The D allele is associated with increased ACE activity in both tissue and plasma. The DD genotype is associated with risk of developing ARDS and mortality. The frequency of the D allele is higher in patients with pulmonary fibrosis, sarcoidosis and berylliosis. The role of this polymorphism has not been studied in the development of BPD in the premature newborn. METHODS: ACE I/D genotype was determined in 245 (194 African-American, 47 Caucasian and 4 Hispanic) mechanically ventilated infants weighing less than 1250 grams at birth and compared to outcome (death and/or development of BPD). RESULTS: The incidence of the D allele in the study population was 0.58. Eighty-eight (35.9%) infants were homozygous DD, 107 (43.7%) were heterozygous ID and 50 (20.4%) were homozygous II. There were no significant differences between genotype groups with respect to ethnic origin, birth weight, gestation, or gender. There was no effect of the ACE I/D polymorphism on mortality or development of BPD (O2 on 28 days or 36 weeks PCA). Secondary outcomes (intraventricular hemorrhage and periventricular leukomalacia) similarly were not influenced by the ACE ID polymorphism. CONCLUSIONS: The ACE I/D polymorphism does not significantly influence the development of BPD in ventilated infants less than 1250 grams.