Human papillomavirus infection with multiple types: pattern of coinfection and risk of cervical disease

OBJECTIVE

We investigated coinfection patterns for 25 human papillomavirus (HPV) types and assessed the risk conferred by multiple HPV types toward cervical disease.

METHODS

Sexually active women (n=5,871) in the NCI-sponsored Costa Rica HPV Vaccine Trial's prevaccination enrollment visit were analyzed. Genotyping for 25 HPVs was performed using SPF(10)/LiPA(25). We calculated odds ratios (ORs) to assess coinfection patterns for each genotype with 24 other genotypes. These ORs were pooled and compared with pair-specific ORs to identify genotype combinations that deviated from the pooled OR. We compared risk of CIN2+/HSIL+between multiple and single infections and assessed additive statistical interactions.

RESULTS

Of the 2478 HPV-positive women, 1070 (43.2%) were infected with multiple types. Multiple infections occurred significantly more frequently than predicted by chance. However, this affinity to be involved in a coinfection (pooled OR for 300 type-type combinations=2.2; 95% confidence interval [CI]=2.1-2.4) was not different across HPV type-type combinations. Compared with single infections, coinfection with multiple α9 species was associated with significantly increased risk of CIN2+(OR=2.2; 95% CI=1.1-4.6) and HSIL+(OR=1.6; 95% CI=1.1-2.4). However, disease risk was similar to the sum of estimated risk from individual types, with little evidence for synergistic interactions.

CONCLUSIONS

Coinfecting HPV genotypes occur at random and lead to cervical disease independently.

Abstract P4-02-18: Antiprogestins as Possible Therapeutic Agents for Breast Cancer Patients Showing a High Expression of the Progesterone Receptor Isoform A

Near 75 percent of breast cancer patients express progesterone (PR) and estrogen (ER) receptors and are potential candidates to receive an endocrine therapy. Most of the endocrine therapies available have been designed to target ER and there is not much information about PR as a therapeutic target for breast cancer treatment. However, extensive clinical and experimental evidence suggest that progestins are associated with the induction and maintenance of the neoplastic phenotype in the mammary gland. Moreover, different antiprogestins including ZK 98299, ZK 230211 and RU-486 proved to exert excellent therapeutic effects in murine mammary carcinomas from the MPA-breast cancer model which express high levels of PR with an increased PR-isoform A/PR-isoform B ratio (PR-A/PR-B) (Lanari C et al, Endocrine Related Cancer, 2009 Feb, Jun;16(2):333-50).

The main goal of this study is to validate these experimental results using human breast cancer samples and to identify breast cancer patients that might benefit from an antiprogestin therapy. In the first part of this study our aim was to set up primary cultures from each breast cancer sample and to evaluate the in vitro response to antiprogestins, correlating this response with the PR-A/PR-B ratio. Tumor samples were obtained at surgery from patients diagnosed with breast cancer at the Magdalena V. de Martinez Hospital from General Pacheco and at the Rivadavia Hospital of Buenos Aires after signing the informed consent (n=70; median age 53.9 years). All tumor samples were processed by mechanical and enzymatic disaggregation and epithelial cells were purified by differential sedimentation techniques. Only 10 percent of the tumor samples succeeded in tissue culture and could be subcultured for further studies in 24 well plates. Cells were grown in culture medium in the presence of 10% fetal calf serum with or without RU-486 (10-8 M) or Tamoxifen (10-8 M). After one week of treatment, the cells were trypsinized and the total number of cells in each well was counted. Treatment with RU-486 or with Tamoxifen induced a decrease in the number of cells as compared to the controls (n=4, P<0.05). In these patients PR-A expression was the same or higher than PR-B as observed by Western Blot. Our results suggest that RU-486 might be an alternative therapy to treat breast carcinomas showing a high expression of PR-A. We still need more successful cultures in order to correlate the in vitro responsiveness with the PR isoform ratio.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-02-18.

Epidemiological study of anti-HPV16/18 seropositivity and subsequent risk of HPV16 and -18 infections

BACKGROUND

Infection with human papillomavirus (HPV) 16 or HPV18 elicits an antibody response, but whether the elicited antibodies protect women against subsequent infection by a homologous HPV type compared with seronegative women is unknown.

METHODS

Study participants were women aged 18-25 years at enrollment in the control group of the ongoing National Cancer Institute-sponsored, community-based, randomized HPV16/18 Costa Rica Vaccine Trial. At enrollment, 2813 participants were negative for cervical HPV16 DNA and 2950 for HPV18 DNA. Women were interviewed regarding sociodemographic data and medical and health history. Medical and pelvic examinations were conducted for all consenting sexually experienced women. Serum samples taken at enrollment were tested for total HPV16/18 antibodies with a polyclonal enzyme-linked immunosorbent assay, and cervical specimens were tested for type-specific HPV DNA over 4 years of follow-up. Using Poisson regression, we compared rate ratios of newly detected cervical HPV16 or HPV18 infection among homologous HPV-seropositive and HPV-seronegative women, adjusting for age, education, marital status, lifetime number of sexual partners, and smoking.

RESULTS

There were 231 newly detected HPV16 infections during 5886 person-years among HPV16-seronegative women compared with 12 newly detected HPV16 infections during 581 person-years among HPV16-seropositive women with the highest HPV16 sero-levels. There were 136 newly detected HPV18 infections during 6352 person-years among HPV18-seronegative women compared with six new infections detected during 675 person-years among HPV18 seropositives with the highest sero-levels. After controlling for risk factors associated with newly detected HPV infection, having high HPV16 antibody titer at enrollment was associated with a reduced risk of subsequent HPV16 infection (women in the highest tertile of HPV16 antibody titers, adjusted rate ratio = 0.50, 95% confidence interval = 0.26 to 0.86 vs HPV16-seronegative women). Similarly, having high HPV18 antibody titer at enrollment was associated with a reduced risk of subsequent HPV18 infection (women in the highest tertile of HPV18 antibody titers, adjusted rate ratio = 0.36, 95% confidence interval = 0.14 to 0.76 vs HPV18-seronegative women).

CONCLUSION

In this study population, having high antibody levels against HPV16 and HPV18 following natural infection was associated with reduced risk of subsequent HPV16 and HPV18 infections.

Genetic admixture and population substructure in Guanacaste Costa Rica

The population of Costa Rica (CR) represents an admixture of major continental populations. An investigation of the CR population structure would provide an important foundation for mapping genetic variants underlying common diseases and traits. We conducted an analysis of 1,301 women from the Guanacaste region of CR using 27,904 single nucleotide polymorphisms (SNPs) genotyped on a custom Illumina InfiniumII iSelect chip. The program STRUCTURE was used to compare the CR Guanacaste sample with four continental reference samples, including HapMap Europeans (CEU), East Asians (JPT+CHB), West African Yoruba (YRI), as well as Native Americans (NA) from the Illumina iControl database. Our results show that the CR Guanacaste sample comprises a three-way admixture estimated to be 43% European, 38% Native American and 15% West African. An estimated 4% residual Asian ancestry may be within the error range. Results from principal components analysis reveal a correlation between genetic and geographic distance. The magnitude of linkage disequilibrium (LD) measured by the number of tagging SNPs required to cover the same region in the genome in the CR Guanacaste sample appeared to be weaker than that observed in CEU, JPT+CHB and NA reference samples but stronger than that of the HapMap YRI sample. Based on the clustering pattern observed in both STRUCTURE and principal components analysis, two subpopulations were identified that differ by approximately 20% in LD block size averaged over all LD blocks identified by Haploview. We also show in a simulated association study conducted within the two subpopulations, that the failure to account for population stratification (PS) could lead to a noticeable inflation in the false positive rate. However, we further demonstrate that existing PS adjustment approaches can reduce the inflation to an acceptable level for gene discovery.

Bivalve population health: multistress to identify hot spots

This study investigated some stress (metals, parasites) and response (immunity, metallothionein) factors in two cockle and two Manila clam populations. Data from eight seasons were averaged to obtain global baseline values. Stress/response characteristics of each population were compared to population health status that was determined through population dynamics parameters. Four different scenarios were discussed: (1) a lightly stressed cockle population with correct population health but with a risk of deterioration (hot spot); (2) a lightly stressed introduced cockle population threatened of extinction. In this case ecological factors were suspected; (3) a moderately stressed clam population with moderate adaptative response. The population was sustainable but the level of stress should not increase (hotspot); and (4) a stressed clam population and unfavourable ecological conditions preventing clam settlement. This monitoring highlighted that the discrepancy between population health and stress levels could be due to insufficient response by bivalves and/or by unfavourable ecological factors.

Visual electrophysiological findings in CHARGE syndrome with bilateral colobomas: a case report

Colobomas are the major ophthalmic manifestation of CHARGE syndrome. Ophthalmological advice may be sought for an infant diagnosed with CHARGE syndrome presenting with coloboma, and electrophysiology can be particularly useful in assessing retinal and cortical function at an early age. Here we describe electrophysiology findings in a four-week-old infant born with bilateral coloboma, more extensive in the right eye, as part of CHARGE syndrome. The left eye showed robust ERGs indicating near-normal rod and cone function. The right eye ERG amplitudes were relatively reduced being around one half to two-thirds that of the left eye ERGs. Flash VEPs were present from both left and right eyes, but the right eye VEP was smaller and delayed relative to that of the left eye. By 5 years of age, right eye acuity was approximately 6/1000 and left eye acuity was 6/12 (Cardiff cards). In cases such as this, it is helpful to give parents a reasonable prediction of visual outcome as soon as possible, allowing instigation of appropriate management and permitting parents to begin to come to terms with the diagnosis. Electrophysiology can provide valuable information on visual function when behavioural testing is limited by the child's ability to co-operate, such as during the early weeks of life.

Risk of miscarriage with bivalent vaccine against human papillomavirus (HPV) types 16 and 18: pooled analysis of two randomised controlled trials

OBJECTIVE

To assess whether vaccination against human papillomavirus (HPV) increases the risk of miscarriage.

DESIGN

Pooled analysis of two multicentre, phase three masked randomised controlled trials

SETTING

Multicentre trials in several continents and in Costa Rica.

PARTICIPANTS

26 130 women aged 15-25 at enrolment; 3599 pregnancies eligible for analysis.

INTERVENTIONS

Participants were randomly assigned to receive three doses of bivalent HPV 16/18 VLP vaccine with AS04 adjuvant (n=13 075) or hepatitis A vaccine as control (n=13 055) over six months.

MAIN OUTCOME MEASURES

Miscarriage and other pregnancy outcomes.

RESULTS

The estimated rate of miscarriage was 11.5% in pregnancies in women in the HPV arm and 10.2% in the control arm. The one sided P value for the primary analysis was 0.16; thus, overall, there was no significant increase in miscarriage among women assigned to the HPV vaccine arm. In secondary descriptive analyses, miscarriage rates were 14.7% in the HPV vaccine arm and 9.1% in the control arm in pregnancies that began within three months after nearest vaccination.

CONCLUSION

There is no evidence overall for an association between HPV vaccination and risk of miscarriage.

TRIAL REGISTRATION

Clinical Trials NCT00128661 and NCT00122681.

Common genetic variants and risk for HPV persistence and progression to cervical cancer

HPV infrequently persists and progresses to cervical cancer. We examined host genetic factors hypothesized to play a role in determining which subset of individuals infected with oncogenic human papillomavirus (HPV) have persistent infection and further develop cervical pre-cancer/cancer compared to the majority of infected individuals who will clear infection.

We evaluated 7140 tag single nucleotide polymorphisms (SNPs) from 305 candidate genes hypothesized to be involved in DNA repair, viral infection and cell entry in 416 cervical intraepithelial neoplasia 3 (CIN3)/cancer cases, 356 HPV persistent women (median: 25 months), and 425 random controls (RC) from the 10,049 women Guanacaste Costa Rica Natural History study. We used logistic regression to compute odds ratios and p-trend for CIN3/cancer and HPV persistence in relation to SNP genotypes and haplotypes (adjusted for age). We obtained pathway and gene-level summary of associations by computing the adaptive combination of p-values. Genes/regions statistically significantly associated with CIN3/cancer included the viral infection and cell entry genes 2′,5′ oligoadenylate synthetase gene 3 (OAS3), sulfatase 1 (SULF1), and interferon gamma (IFNG); the DNA repair genes deoxyuridine triphosphate (DUT), dosage suppressor of mck 1 homolog (DMC1), and general transcription factor IIH, polypeptide 3 (GTF2H4); and the EVER1 and EVER2 genes (p<0.01). From each region, the single most significant SNPs associated with CIN3/cancer were OAS3 rs12302655, SULF1 rs4737999, IFNG rs11177074, DUT rs3784621, DMC1 rs5757133, GTF2H4 rs2894054, EVER1/EVER2 rs9893818 (p-trends≤0.001). SNPs for OAS3, SULF1, DUT, and GTF2H4 were associated with HPV persistence whereas IFNG and EVER1/EVER2 SNPs were associated with progression to CIN3/cancer. We note that the associations observed were less than two-fold. We identified variations DNA repair and viral binding and cell entry genes associated with CIN3/cancer. Our results require replication but suggest that different genes may be responsible for modulating risk in the two critical transition steps important for cervical carcinogenesis: HPV persistence and disease progression.

Outbreak of 2009 pandemic influenza A(H1N1), Los Lagos, Chile, April-June 2009

On 17 May 2009, the first two cases of 2009 pandemic influenza A(H1N1) were confirmed in the Metropolitan region (Santiago, Chile). On 6 June 2009, Chile reported 500 confirmed cases, seven severe and two fatal. Because six of the severe cases and the two deaths occurred in the region of Los Lagos in southern Chile, a retrospective study was conducted using data on emergency room visits as well as laboratory viral surveillance, during the period from 1 April to 31 May, in order to establish the date of the beginning of the outbreak. From 1 to 27 June, data were collected in real time, to establish the real magnitude of the outbreak, describe its transmission, clinical severity and secondary attack rates. Confirmed cases, their household contacts and healthcare workers were interviewed. This analysis showed that the outbreak in Los Lagos started on 28 April. By 27 June, a total of 14.559 clinical cases were identified, affecting mostly 5-19 year-olds. The effective reproduction number during the initial phase (20 days) was 1.8 (1.6-2.0). Of the 190 confirmed cases with severe acute respiratory infection, 71 (37.4%) presented a risk condition or underlying illness.

How To Deal with Additional Findings Seen in Pre-Therapeutic Breast MRI and Their Impact on Therapeutic Approach. A Prospective Longitudinal Single-Institutional Study in 465 Patients

Background: Accurate assessment of the extent of breast cancer with breast MRI (BMRI) yields additional findings (AF) that must be characterized in order to guide treatment. The aim of our study was to analyze the work-up of AF seen in pre-therapeutic BMRI and their impact on therapeutic approach and re-excision rates.Methods: From 07/2002 to 04/2007 we studied prospectively 465 consecutive patients with a diagnosis of breast cancer that underwent a pre-treatment BMRI to evaluate disease extent. BMRI studies were performed with a 1,0 and a 1,5 T magnet and coronal T2-weighted fast spin-echo and contrast-enchanced T1-weighted 3D gradient-echo sequences were evaluated. Post-processing included parametric, multiplanar reconstructions and maximum intensity projections. Fischer's scale was used to characterize additional lesions (AL). AL &gt;5 mm were classified as: increase in tumor size, multifocal, multicentric and contralateral disease. AF that would potentially change therapeutic approach were re-evaluated with 2nd-look ultrasound (US), biopsied if found and/or marked with clips or with a radioisotope (ROLL). BI-RADS 3 lesions were followed up with BMRI. Gold standards were pathology reports and follow-up &gt;2 years for benign lesions. Therapeutic change based on MRI findings was deemed correct in malignant AF and incorrect if pathology was benign. Re-excision rates and disease-free intervals were calculated.Results. A total of 280 AF were found in 222 (47,7%) patients. US studies were performed in 111 patients, in 99 of which the AL (89,1%) was found. 63 patients underwent biopsies and 48 of them (76,1%) were malignant. ROLL procedures were performed in 32 patients and malignancy rate was 65,6%. Follow-up BMRI studies for BI-RADS 3 lesions were performed in 42 patients (9%). BMRI found index lesions seen by mammography or US in 98,9% of the patients and did not find additional multifocal or multicentric disease in 10 patients, yielding a total negative predictive value of 96,7% for BMRI (6 invasive and 9 intraductal cancers). Therapeutic approach was changed in 107 patients (23%) and considered correct in 92 (86%) representing 19,7% of all patients and incorrect in 15 (14%) corresponding to 3,2% of the total. Re-excision due to positive margins during the first 6 months was performed in 39/323 patients treated with conservative surgery (re-excision rate of 12%). Mean follow-up was 48,4 months (m) (6,7-81,4 m) and mean disease-free interval was 45 m (6,7-81,4 m).Conclusion: Work-up of AF diagnosed in BMRI allows accurate treatment adjusted to disease extent in 96,8% of the patients. Additional work-up using US and close correlation with the rest of conventional modalities is the mandatory behaviour to ensure an integrated evaluation of AF. This policy allows a correct treatment in 86% of the patients with potential therapeutic change. Overtreatment was induced in 14% of these patients. Regarding the overall series of 465 patients submitted to BMRI, the 15 patients who were overtreated represent 3,2% of the total. The precision level of preoperative MRI in this scenario is clearly superior to conventional modalities when combined in an integrated multimodality approach.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4023.

Complete genome sequence of the sugarcane nitrogen-fixing endophyte Gluconacetobacter diazotrophicus Pal5

BACKGROUND

Gluconacetobacter diazotrophicus Pal5 is an endophytic diazotrophic bacterium that lives in association with sugarcane plants. It has important biotechnological features such as nitrogen fixation, plant growth promotion, sugar metabolism pathways, secretion of organic acids, synthesis of auxin and the occurrence of bacteriocins.

RESULTS

Gluconacetobacter diazotrophicus Pal5 is the third diazotrophic endophytic bacterium to be completely sequenced. Its genome is composed of a 3.9 Mb chromosome and 2 plasmids of 16.6 and 38.8 kb, respectively. We annotated 3,938 coding sequences which reveal several characteristics related to the endophytic lifestyle such as nitrogen fixation, plant growth promotion, sugar metabolism, transport systems, synthesis of auxin and the occurrence of bacteriocins. Genomic analysis identified a core component of 894 genes shared with phylogenetically related bacteria. Gene clusters for gum-like polysaccharide biosynthesis, tad pilus, quorum sensing, for modulation of plant growth by indole acetic acid and mechanisms involved in tolerance to acidic conditions were identified and may be related to the sugarcane endophytic and plant-growth promoting traits of G. diazotrophicus. An accessory component of at least 851 genes distributed in genome islands was identified, and was most likely acquired by horizontal gene transfer. This portion of the genome has likely contributed to adaptation to the plant habitat.

CONCLUSION

The genome data offer an important resource of information that can be used to manipulate plant/bacterium interactions with the aim of improving sugarcane crop production and other biotechnological applications.

Virus-like particles associated with brown muscle disease in Manila clam, Ruditapes philippinarum, in Arcachon Bay (France)

Recently, Manila clam, Ruditapes philippinarum, populations have suffered mortalities in Arcachon Bay (SW France). Mortality was associated with extensive lesions of the posterior adductor muscle, which become progressively brown and calcified. Ultrastructural observations by transmission electron microscopy revealed tissue degradation with necrotized muscle fibres and granulocytomas. Unenveloped virus-like particles (VLPs) were detected in muscle, granulocytic, epithelial and rectal cells. VLPs were abundant in the extracellular space, in the cytoplasm (free or enclosed in vesicles) and in the nucleoplasm of granulocytes. Nuclei and mitochondria of granulocytes displayed changes which suggested reactive oxygen species production and apoptosis induction. VLPs exhibited an icosahedral structure with a diameter of 25 to 35 nm. These observations suggest that the VLPs could belong to the family Picornaviridae or the Parvoviridae.

Hepatitis C virus compartmentalization and infection recurrence after liver transplantation

Hepatitis C virus (HCV) compartmentalization may have important implications in the pathogenesis of HCV infection. The aim of this study was to investigate the presence and relevance of HCV compartmentalization in the setting of liver transplantation (LT). We collected samples of serum, peripheral blood mononuclear cells (PBMC), perihepatic lymph nodes (PLN) and liver explant at the time of LT, and serum and PBMC after transplantation from 57 HCV-infected cirrhotic patients undergoing LT: 38 individuals received antiviral treatment before LT and 19 were untreated controls. HCV-RNA levels were determined by real-time PCR and the hypervariable region 1 (HVR-1) was sequenced. HCV-RNA was detected in all samples from control patients. In virological responders, recurrence after LT was associated with residual HCV-RNA in the liver explant. Within the entire cohort, 47% of patients harbored differences in direct sequences from distinct compartments. Quasispecies analysis revealed that in most cases, HVR-1 sequences recovered after infection recurrence were identical or closely related to those isolated from the liver explant and serum at the time of LT. Our study shows that a significant proportion of HCV-infected cirrhotic patients exhibit compartmentalization. Viral variants originating within the liver appear to be the main cause of HCV recurrence after LT.

Beneficial effects on the reproductive performance of sows of administering prostaglandin analogues after farrowing

Twenty-four to 36 hours after farrowing, 192 sows were treated with a single intramuscular injection (2 ml per animal) of a prostaglandin analogue; 102 were treated with cloprostenol racemate and 97 with dinoprost tromethamine, and 90 were left untreated. There were no statistically significant differences between the groups in the percentages of sows that came into oestrus by eight days after weaning or conceived by eight days after weaning. Significantly more piglets were born per litter (10.71 and 11.00 piglets in the cloprostenol and dinoprost groups, respectively) and born alive (10.22 and 10.41, respectively) than in the controls (9.24 piglets born per litter and 8.66 piglets born alive).

Common genetic variation in TP53 and risk of human papillomavirus persistence and progression to CIN3/cancer revisited

Driven by findings that human papillomavirus (HPV)-induced degradation of p53 differs by a TP53 polymorphism at codon 72 (Pro72Arg), past studies of TP53 genetic variants and cervical cancer have focused on this nonsynonymous polymorphism, with mixed results. We analyzed common single nucleotide polymorphisms (SNP) across the TP53 locus in a population-based nested case-control study in Guanacaste, Costa Rica. We evaluated 11 SNPs, including Pro72Arg (rs1042522), among 1,281 women: 465 with cervical intraepithelial neoplasia grade 3/cancer (CIN3+), 380 with HPV persistence (median, 25 months), and 436 random population controls. We combined HPV persistence and CIN3+ into one case group because they did not differ in TP53 genotypic frequencies and calculated odds ratios and 95% confidence intervals (CI) for individual SNPs and inferred haplotypes. We observed that proline at codon 72 was associated with increased risk of CIN3+/persistence compared with population controls. Relative to GG (Arg), the CG (Pro/Arg) and CC (Pro) genotypes had a 1.3-fold (95% CI, 0.99-1.6) and 1.8-fold (95% CI, 1.2-2.7) increased risk, respectively (P(trend) < 0.01). rs12951053 and rs1642785 were also associated with CIN3+/persistence (P (trend), 0.05 and 0.04, respectively), as was a haplotype containing the codon 72 variant (rs1042522), rs12951053, rs1642785, and rs12947788 (odds ratio, 1.6; 95% CI, 1.1-2.3 versus the most common haplotype, which comprised the major alleles for all 11 SNPs). Although genetic variation in TP53 might affect the natural history of HPV and cervical cancer, further work is needed to elucidate the possible mechanism.

Genetic relationships between seven Spanish native breeds of cattle

Ten genetic markers were studied in seven Spanish native cattle breeds, using a total of 725 animals. Of the ten, two were found to be monomorphic in all seven breeds. The genetic relationships of the seven breeds are estimated by three different genetic-statistical methods (genetic distances, main coordinate analysis and cluster analysis), which indicate three clearly distinct groups of populations: one where the Cárdena Andaluza and Alistana Sanabresa are very closely related, one comprising Sayaguesa, Morucha, Asturiana de los Valles and Asturiana de la Montaña cattle, and a third, genetically distant from the other two, comprising only Blanca Cacereña. The dendrogram drawn from the genetic distances matrix would seem to imply that the seven breeds are descended from different ancestors.

NADH diaphorase polymorphism in goat erythrocytes

This paper describes for the first time polymorphism of the erythrocyte diaphorase in goats. Three diaphorase 1 phenotypes were observed in the red cells of goats. Breeding data indicated that polymorphism was controlled by two autosomal codominant alleles, DiaF and DiaS, the frequencies of which were determined in 14 different Spanish breeds of goat.

Erythrocyte potassium polymorphism in 14 Spanish goat breeds

The existence of polymorphism for erythrocyte potassium (Ke) is confirmed in certain Spanish breeds of goat. A statistical boundary is established between two caprine populations: low (LK) and high (HK) red cell potassium, the dividing line being set at 45 m-equiv/l of Ke. Both types are shown to be controlled genetically by an autosomal locus with two alleles KL and Kh, being KL dominant over Kh. The gene frequencies of KL and Kh are determined in 14 native Spanish breeds of goat.

Genetic relationships between 14 native Spanish breeds of goat

The genetic distances separating 14 Spanish goat breeds are calculated from gene frequency data of 14 genetic blood markers (GSH, Ke, Hb, Dia, Ct, MDH, CA, X, NP, Alp, Am, Cp, Tf and Al). Working from the matrix of Nei's genetic distances we drew a dendrogram demonstrating a great genetic similarity among populations from Negra Serrana, Zamorana, Guadarrama, Retinta, Blanca Andaluza, Berciana and Pirenaica on one hand; and Canaria, Murciana, Blanca Celtibérica, Verata, Palmera, Malagueña and Granadina on the other. We discuss the similarities and differences within our classification using gene frequency data of the blood genetic markers studied, and classifications based chiefly on morphological and production data.

At environmental doses, dietary methylmercury inhibits mitochondrial energy metabolism in skeletal muscles of the zebra fish (Danio rerio)

The neurotoxic compound methylmercury (MeHg) is a commonly encountered pollutant in the environment, and constitutes a hazard for human health through fish eating. To study the impact of MeHg on mitochondrial structure and function, we contaminated the model fish species Danio rerio with food containing 13 microg of MeHg per gram, an environmentally relevant dose. Mitochondria from contaminated zebrafish muscles presented structural abnormalities under electron microscopy observation. In permeabilized muscle fibers, we observed, a strong inhibition of both state 3 mitochondrial respiration and functionally isolated maximal cytochrome c oxidase (COX) activity after 49 days of MeHg exposure. However, the state 4 respiratory rate remained essentially unchanged. This suggested a defect at the level of ATP synthesis. Accordingly, we measured a dramatic decrease in the rate of ATP release by skinned muscle fibers using either pyruvate and malate or succinate as respiratory substrates. However, the amount and the assembly of the ATP synthase were identical in both control and contaminated muscle mitochondrial fractions. This suggests that MeHg induced a decoupling of mitochondrial oxidative phosphorylation in the skeletal muscle of zebrafish. Western blot analysis showed a 30% decrease of COX subunit IV levels, a 50% increase of ATP synthase subunit alpha, and a 40% increase of the succinate dehydrogenase Fe/S protein subunit in the contaminated muscles. This was confirmed by the analysis of gene expression levels, using RT-PCR. Our study provides a basis for further analysis of the deleterious effect of MeHg on fish health via mitochondrial impairment.