Genetic interactions involving major genes at the dwarf locus in egg-type chickens

Three egg-type stocks segregating dwarf (dw) and bantam (dwB) genes in female progeny were produced from the same 18 heterozygous (dwB/dw) sires used to inseminate dams of three different genotypes: normal (dw+), dwarf (dw) and bantam (dwB) dams. The heritability of 8-week body weight estimated from full-sibs of the same phenotype of progeny was 0.40, and that estimated from paternal half-sibs of the same phenotype (dwarf or bantam), and from the same genotype of dam was 0.38. Therefore, maternal and non-additive effects within genotypic classes of dam made little contribution to the genetic variance for 8-week body weight among their progeny. The interaction of sires (S) with genotypes (dw+, dw and dwB) of dam (G) was significant at the 5% level. This indicates that the rankings of the sires within each one of the three genotypes of dam were not the same, probably due to non-additive genetic variation among genotypes of dams. The evidence indicated that in general the genes from individual sires combined differently with each type of dam (G). Those genes which combined well with the genes from normal (dw+) dams combined poorly with both the genes from the dwarf (dw) and the genes from the bantam (dwB) dams. The interaction of sires (S) with phenotypes (dwarf and bantam) of progeny (P) was significant at the 10% level. The results indicated a probable gene x genotype interaction for 8-week weight between genes at the dwarf locus (dw and dwB) and the background genotype (single and/or polygenes). The correlation among paternal half-sibs was influenced more by the S x G than by the S x P interaction, but the effects tended to be cumulative

Estimates of genetic and phenotypic parameters in a segregant population of rice irrigated by continuous flooding

Estimates of genetic and phenotypic parameters were obtained by using data from families of a recurrent selection program in rice. An experiment using population CNA-IRAT 4ME/1/1 was conducted at two locations (Lambari and Cambuquira) in the State of Minas Gerais, Brazil. At Lambari, families S0:2 and S0:3 were assessed during crop seasons 1992/1993 and 1993/1994, respectively. In the Cambuquira trial, only S0:3 families were tested in 1993/1994. The experimental design was a 10 x 10 lattice with three replications. The following traits were assessed: grain yield (GY), mean number of days to flowering (FL), plant height (PH), and the incidence of neck blast (NB) caused by Pyricularia grisea and grain staining (GS) caused by Drechslera oryzae. This population proved to be promising for recurrent selection, as it had high average yield and genetic variability. Heritability estimates obtained using variance components were generally greater than estimates of realized heritability, and heritability obtained by parent-offspring regression

A search for RFLP markers to identify genes for aluminum tolerance in maize

The objective of this study was to identify restriction fragment length polymorphism (RFLP) markers linked to QTLs that control aluminum (Al) tolerance in maize. The strategy used was bulked segregant analysis (BSA) and the genetic material utilized was an F2 population derived from a cross between the Al-susceptible inbred line L53 and Al-tolerant inbred line L1327. Both lines were developed at the National Maize and Sorghum Research Center - CNPMS/EMBRAPA. The F2 population of 1554 individuals was evaluated in a nutrient solution containing a toxic concentration of Al and relative seminal root length (RSRL) was used as a phenotypic measure of tolerance. The RSRL frequency distribution was continuous, but skewed towards Al-susceptible individuals. Seedlings of the F2 population which scored the highest and the lowest RSRL values were transplanted to the field and subsequently selfed to obtain F3 families. Thirty F3 families (15 Al-susceptible and 15 Al-tolerant) were evaluated in nutrient solution, using an incomplete block design, to identify those with the smallest variances for aluminum tolerance and susceptibility. Six Al-susceptible and five Al-tolerant F3 families were chosen to construct one pool of Al-susceptible individuals, and another of Al-tolerant, herein referred as "bulks", based on average values of RSRL and genetic variance. One hundred and thirteen probes were selected, with an average interval of 30 cM, covering the 10 maize chromosomes. These were tested for their ability to discriminate the parental lines. Fifty-four of these probes were polymorphic, with 46 showing codominance. These probes were hybridized with DNA from the two contrasting bulks. Three RFLPs on chromosome 8 distinguished the bulks on the basis of band intensity. DNA of individuals from the bulks was hybridized with these probes and showed the presence of heterozygous individuals in each bulk. These results suggest that in maize there is a region related to aluminum tolerance on chromosome 8

Using the best linear predictor (BLP) in the selection between and among half-sib progenies of the CMS-39 maize population

Data of corn ear production (kg/ha) of 196 half-sib progenies (HSP) of the maize population CMS-39 obtained from experiments carried out in four environments were used to adapt and assess the BLP method (best linear predictor) in comparison with to the selection among and within half-sib progenies (SAWHSP). The 196 HSP of the CMS-39 population developed by the National Center for Maize and Sorghum Research (CNPMS-EMBRAPA) were related through their pedigree with the recombined progenies of the previous selection cycle. The two methodologies used for the selection of the twenty best half-sib progenies, BLP and SAWHSP, led to similar expected genetic gains. There was a tendency in the BLP methodology to select a greater number of related progenies because of the previous generation (pedigree) than the other method. This implies that greater care with the effective size of the population must be taken with this method. The SAWHSP methodology was efficient in isolating the additive genetic variance component from the phenotypic component. The pedigree system, although unnecessary for the routine use of the SAWHSP methodology, allowed the prediction of an increase in the inbreeding of the population in the long term SAWHSP selection when recombination is simultaneous to creation of new progenies.

Effects of naltrexone and cross-tolerance to morphine in a learned helplessness paradigm

Opiates have been implicated in learned helplessness (LH), a phenomenon known to be related to opiate stress-induced analgesia (SIA). In the present study, we investigated the role of opiates in the induction of LH and SIA under different conditions. Adult female Wistar rats were trained either by receiving 60 inescapable 1-mA footshocks (IS group, N = 114) or by confinement in the shock box (control or NS group, N = 92). The pain threshold of some of the animals was immediately evaluated in a tail-flick test while the rest were used 24 h later in a shuttle box experiment to examine their escape performance. The opiate antagonist naltrexone (0 or 8 mg/kg, ip) and the previous induction of cross-tolerance to morphine by the chronic administration of morphine (0 or 10 mg/kg, sc, for 13 days) were used to identify opiate involvement. Analysis of variance revealed that only animals in the IS group demonstrated antinociception and an escape deficit, both of which were resistant to the procedures applied before the training session. However, the escape deficit could be reversed if the treatments were given before the test session. We conclude that, under our conditions, induction of the LH deficit in escape performance is not opiate-mediated although its expression is opiate-modulated

Absence of linkage between MHC and a gene involved in susceptibility to human schistosomiasis

Six hundred million people are at risk of infection by Schistosoma mansoni. MHC haplotypes have been reported to segregate with susceptibility to schistosomiasis in murine models. In humans, a major gene related to susceptibility/resistance to infection by S. mansoni (SM1) and displaying the mean fecal egg count as phenotype was detected by segregation analysis. This gene displayed a codominant mode of inheritance with an estimated frequency of 0.20-0.25 for the deleterious allele and accounted for more than 50% of the variance of infection levels. To determine if the SM1 gene segregates with the human MHC chromosomal region, we performed a linkage study by the lod score method. We typed for HLA-A, B, C, DR and DQ antigens in 11 informative families from an endemic area for schistosomiasis in Bahia, Brazil, by the microlymphocytotoxicity technique. HLA-DR typing by the polymerase chain reaction with sequence-specific primers (PCR-SSP) and HLA-DQ were confirmed by PCR-sequence-specific oligonucleotide probes (PCR-SSOP). The lod scores for the different q values obtained clearly indicate that there is no physical linkage between HLA and SM1 genes. Thus, susceptibility or resistance to schistosomiasis, as defined by mean fecal egg count, is not primarily dependent on the host's HLA profile. However, if the HLA molecule plays an important role in specific immune responses to S. mansoni, this may involve the development of the different clinical aspects of the disease such as granuloma formation and development of hepatosplenomegaly.

Transforming growth factor beta activity in urine of patients with type 2 diabetes and diabetic nephropathy

Diabetic nephropathy (DN) is characterized structurally by progressive mesangial deposition of extracellular matrix (ECM). Transforming growth factor-ß (TGF-ß) is considered to be one of the major cytokines involved in the regulation of ECM synthesis and degradation. Several studies suggest that an increase in urinary TGF-ß levels may reflect an enhanced production of this polypeptide by the kidney cells. We evaluated TGF-ß in occasional urine samples from 14 normal individuals and 23 patients with type 2 diabetes (13 with persistent proteinuria >500 mg/24 h, DN, 6 with microalbuminuria, DMMA, and 4 with normal urinary albumin excretion, DMN) by enzyme immunoassay. An increase in the rate of urinary TGF-ß excretion (pg/mg UCreat.) was observed in patients with DN (296.07 ± 330.77) (P<0.001) compared to normal individuals (17.04 ± 18.56) (Kruskal-Wallis nonparametric analysis of variance); however, this increase was not observed in patients with DMMA (25.13 ± 11.30) or in DMN (18.16 ± 11.82). There was a positive correlation between the rate of urinary TGF-ß excretion and proteinuria (r = 0.70, a = 0.05) (Pearson's analysis), one of the parameters of disease progression.

Functional dyspepsia: relationship between clinical subgroups and Helicobacter pylori status in Western Turkey

The etiology of functional dyspepsia is not known. The objective of the present study was to determine the characteristics of functional dyspepsia in Western Turkey. We divided 900 patients with functional dyspepsia into three subgroups according to symptoms: ulcer-like (UL), 321 (35.6%), motility disorder-like (ML), 281 (31.2%), and the combination (C) of these symptoms, 298 (33.1%). All patients were submitted to endoscopic evaluation, with two biopsies taken from the cardia and corpus, and four from the antrum of the stomach. All biopsy samples were studied for Helicobacter pylori (Hp) density, chronic inflammation, activity, intestinal metaplasia, atrophy, and the presence of lymphoid aggregates by histological examination. One antral biopsy was used for the rapid urease test. Tissue cagA status was determined by PCR from an antral biopsy specimen by a random sampling method. We also determined the serum levels of tumor necrosis factor-alpha (TNF-alpha) and gastrin by the same method. Data were analyzed statistically by the Kolmogorov-Smirnov test and by analysis of variance. Hp and cagA positivity was significantly higher in the UL subgroup than in the others. The patients in the ML subgroup had the lowest Hp and cagA positivity and Hp density. The ML subgroup also showed the lowest level of Hp-induced inflammation among all subgroups. The serum levels of TNF-alpha and gastrin did not reveal any difference between groups. Our findings show a poor association of Hp with the ML subgroup of functional dyspepsia, but a stronger association with the UL and C subgroups.

Hypercaloric cafeteria-like diet induced UCP3 gene expression in skeletal muscle is impaired by hypothyroidism

The uncoupling protein UCP3 belongs to a family of mitochondrial carriers located in the inner mitochondrial membrane of certain cell types. It is expressed almost exclusively at high levels in skeletal muscle and its physiological role has not been fully determined in this tissue. In the present study we have addressed the possible interaction between a hypercaloric diet and thyroid hormone (T3), which are strong stimulators of UCP3 gene expression in skeletal muscle. Male Wistar rats weighing 180 ± 20 g were rendered hypothyroid by thyroidectomy and the addition of methimazole (0.05%; w/v) to drinking water after surgery. The rats were fed a hypercaloric cafeteria diet (68% carbohydrates, 13% protein and 18% lipids) for 10 days and sacrificed by decapitation. Subsequently, the gastrocnemius muscle was dissected, total RNA was isolated with Trizol™ and UCP3 gene expression was determined by Northern blotting using a specific probe. Statistical analysis was performed by one-way analysis of variance (ANOVA) followed by the Student-Newman-Keuls post-test. Skeletal muscle UCP3 gene expression was decreased by 60% in hypothyroid rats and UCP3 mRNA expression was increased 70% in euthyroid cafeteria-fed rats compared to euthyroid chow-fed animals, confirming previous studies. Interestingly, the cafeteria diet was unable to stimulate UCP3 gene expression in hypothyroid animals (40% lower as compared to euthyroid cafeteria-fed animals). The results show that a hypercaloric diet is a strong stimulator of UCP3 gene expression in skeletal muscle and requires T3 for an adequate action.

Effects of metformin treatment on luteal phase progesterone concentration in polycystic ovary syndrome

The causes of luteal phase progesterone deficiency in polycystic ovary syndrome (PCOS) are not known. To determine the possible involvement of hyperinsulinemia in luteal phase progesterone deficiency in women with PCOS, we examined the relationship between progesterone, luteinizing hormone (LH) and insulin during the luteal phase and studied the effect of metformin on luteal progesterone levels in PCOS. Patients with PCOS (19 women aged 18-35 years) were treated with metformin (500 mg three times daily) for 4 weeks prior to the test cycle and throughout the study period, and submitted to ovulation induction with clomiphene citrate. Blood samples were collected from control (N = 5, same age range as PCOS women) and PCOS women during the late follicular (one sample) and luteal (3 samples) phases and LH, insulin and progesterone concentrations were determined. Results were analyzed by one-way analysis of variance (ANOVA), Duncan's test and Karl Pearson's coefficient of correlation (r). The endocrine study showed low progesterone level (4.9 ng/ml) during luteal phase in the PCOS women as compared with control (21.6 ng/ml). A significant negative correlation was observed between insulin and progesterone (r = -0.60; P < 0.01) and between progesterone and LH (r = -0.56; P < 0.05) concentrations, and a positive correlation (r = 0.83; P < 0.001) was observed between LH and insulin. The study further demonstrated a significant enhancement in luteal progesterone concentration (16.97 ng/ml) in PCOS women treated with metformin. The results suggest that hyperinsulinemia/insulin resistance may be responsible for low progesterone levels during the luteal phase in PCOS. The luteal progesterone level may be enhanced in PCOS by decreasing insulin secretion with metformin.

Cytokine profile and nitric oxide levels in sera from patients with brucellosis

The aims of this study were to investigate the serum levels of some cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin 1ß (IL-1ß), IL-2R, IL-6, and IL-8] and nitric oxide (NO) levels in patients with untreated brucellosis and to test the correlation of these parameters with each other. The study was conducted on 67 subjects, 37 patients with brucellosis and 30 healthy individuals with no history of Brucella infection. Brucellosis was identified by a positive blood culture and/or increased Brucella antibodies in serological tests in addition to compatible clinical symptoms. Cytokine profile analysis was performed by the immulite chemiluminescent enzyme immunometric assay whose inter- and intra-assay coefficients of variance were 2.6-3.6 and 4.4-8.5%, respectively. The levels of nitrites/nitrates, which are representative of NO levels, were measured by the Griess method. Patients with brucellosis had significantly elevated serum levels of nitrites/nitrates, IL-2R, IL-6 and IL-8 (mean ± SD, 102.8 ± 23.8 µmol/l, 806.1 ± 58.5 U/ml, 21.1 ± 2.3 pg/ml, and 8.8 ± 1.6 pg/ml, respectively) compared to healthy controls, whereas TNF-alpha and IL-1ß levels were unchanged. No statistically significant correlation was detected between any of the studied cytokine levels and nitrate/nitrite concentrations according to Pearson's linear correlation test. We conclude that only IL-6, IL-8 and IL-2R are elevated in brucellosis and the extent of elevation depends on the severity and clinical pattern of the disease. Moderate elevation in serum NO was comparable to that observed in previous studies. This explains the absence or very rare occurrence of septic shock in brucellosis.

Category fluency test: effects of age, gender and education on total scores, clustering and switching in Brazilian Portuguese-speaking subjects

Verbal fluency tests are used as a measure of executive functions and language, and can also be used to evaluate semantic memory. We analyzed the influence of education, gender and age on scores in a verbal fluency test using the animal category, and on number of categories, clustering and switching. We examined 257 healthy participants (152 females and 105 males) with a mean age of 49.42 years (SD = 15.75) and having a mean educational level of 5.58 (SD = 4.25) years. We asked them to name as many animals as they could. Analysis of variance was performed to determine the effect of demographic variables. No significant effect of gender was observed for any of the measures. However, age seemed to influence the number of category changes, as expected for a sensitive frontal measure, after being controlled for the effect of education. Educational level had a statistically significant effect on all measures, except for clustering. Subject performance (mean number of animals named) according to schooling was: illiterates, 12.1; 1 to 4 years, 12.3; 5 to 8 years, 14.0; 9 to 11 years, 16.7, and more than 11 years, 17.8. We observed a decrease in performance in these five educational groups over time (more items recalled during the first 15 s, followed by a progressive reduction until the fourth interval). We conclude that education had the greatest effect on the category fluency test in this Brazilian sample. Therefore, we must take care in evaluating performance in lower educational subjects.

Maternal aggression in Wistar rats: effect of 5-HT2A/2C receptor agonist and antagonist microinjected into the dorsal periaqueductal gray matter and medial septum

The objective of the present study was to assess the role of the 5-HT2A/2C receptor at two specific brain sites, i.e., the dorsal periaqueductal gray matter (DPAG) and the medial septal (MS) area, in maternal aggressive behavior after the microinjection of either a 5-HT2A/2C receptor agonist or antagonist. Female Wistar rats were microinjected on the 7th postpartum day with the selective agonist alpha-methyl-5-hydroxytryptamine maleate (5-HT2A/2C) or the antagonist 5-HT2A/2C, ketanserin. The agonist was injected into the DPAG at 0.2 (N = 9), 0.5 (N = 10), and 1.0 µg/0.2 µl (N = 9), and the antagonist was injected at 1.0 µg/0.2 µl (N = 9). The agonist was injected into the medial septal area (MS) at 0.2 (N = 9), 0.5 (N = 7), and 1.0 µg/0.2 µl (N = 6) and the antagonist was injected at 1.0 µg/0.2 µl (N = 5). For the control, saline was injected into the DPAG (N = 7) and the MS (N = 12). Both areas are related to aggressive behavior and contain a high density of 5-HT receptors. Non-aggressive behaviors such as horizontal locomotion (walking) and social investigation and aggressive behaviors such as lateral threat (aggressive posture), attacks (frontal and lateral), and biting the intruder were analyzed when a male intruder was placed into the female resident's cage. For each brain area studied, the frequency of the behaviors was compared among the various treatments by analysis of variance. The results showed a decrease in maternal aggressive behavior (number of bites directed at the intruder) after microinjection of the agonist at 0.2 and 1.0 µg/0.2 µl (1.6 ± 0.7 and 0.9 ± 0.3) into the DPAG compared to the saline group (5.5 ± 1.1). There was no dose-response relationship with the agonist. The present findings suggest that the 5-HT2A/2C receptor agonist has an inhibitory effect on maternal aggressive behavior when microinjected into the DPAG and no effect when microinjected into the MS. Ketanserin (1.0 µg/0.2 µl) decreased locomotion when microinjected into the DPAG and MS, but did not affect aggressive behavior. We interpret these findings as evidence for a specific role of 5-HT2A/2C receptors in the DPAG in the inhibition of female aggressive behavior, dissociated from those on motor activity.

Critical analysis of autoregressive and fast Fourier transform markers of cardiovascular variability in rats and humans

The autonomic nervous system plays an important role in physiological and pathological conditions, and has been extensively evaluated by parametric and non-parametric spectral analysis. To compare the results obtained with fast Fourier transform (FFT) and the autoregressive (AR) method, we performed a comprehensive comparative study using data from humans and rats during pharmacological blockade (in rats), a postural test (in humans), and in the hypertensive state (in both humans and rats). Although postural hypotension in humans induced an increase in normalized low-frequency (LFnu) of systolic blood pressure, the increase in the ratio was detected only by AR. In rats, AR and FFT analysis did not agree for LFnu and high frequency (HFnu) under basal conditions and after vagal blockade. The increase in the LF/HF ratio of the pulse interval, induced by methylatropine, was detected only by FFT. In hypertensive patients, changes in LF and HF for systolic blood pressure were observed only by AR; FFT was able to detect the reduction in both blood pressure variance and total power. In hypertensive rats, AR presented different values of variance and total power for systolic blood pressure. Moreover, AR and FFT presented discordant results for LF, LFnu, HF, LF/HF ratio, and total power for pulse interval. We provide evidence for disagreement in 23% of the indices of blood pressure and heart rate variability in humans and 67% discordance in rats when these variables are evaluated by AR and FFT under physiological and pathological conditions. The overall disagreement between AR and FFT in this study was 43%.

Celecoxib reduces symptoms in men with difficult chronic pelvic pain syndrome (Category IIIA)

We investigated the effectiveness of celecoxib in reducing symptoms in patients with difficult chronic pelvic pain syndrome (CPPS), NIH category IIIA. Sixty-four patients with category IIIA CPPS were randomized into two groups of 32 subjects each. One group was treated with celecoxib (200 mg daily) and the other with placebo. All patients underwent treatment for 6 weeks and were evaluated clinically before (baseline) and after 1, 2, 4, 6, and 8 weeks of treatment. The evaluation included the NIH Chronic Prostatitis Symptom Index (NIH-CPSI) and a subjective global assessment (SGA). Repeated measures analysis of variance was used to evaluate treatment and time effects and their interaction. A decrease (means ± SD) in total NIH-CPSI score from 23.91 ± 5.27 to 15.88 ± 2.51 in the celecoxib group and from 24.25 ± 5.09 to 19.50 ± 2.50 in the placebo group was observed during treatment (0 to 6 weeks). A statistically significant decrease was observed in pain subscore (P < 0.006), quality of life subscore (P < 0.032) and total NIH-CPSI score (P < 0.015) after 2, 4 and 6 weeks, but not in urinary subscore. In addition, 38% of the celecoxib and 13% of the placebo subjects had at least a moderate improvement in SGA. The trend was similar for the NIH-CPSI scores. However, the response to treatment in terms of total NIH-CPSI score or subscore was not significantly different from placebo after interruption of treatment for 2 weeks. Our results show that celecoxib provides significant symptomatic improvement limited to the duration of the therapy in patients with difficult category IIIA CPPS compared to placebo.