DNA polymorphisms associated with lactase persistence, self-perceived symptoms of lactose intolerance, milk and dairy consumption, and ancestry, in the Uruguayan population

Uruguay has one of the highest per capita milk intakes worldwide, even with a limited supply of lactose-free products; furthermore, the admixed nature of its population is well known, and various frequencies of lactase persistence (LP) are observed in the source populations. We aimed to contribute to the understanding of the relation between allelic variants associated with LP, milk consumption, digestive symptoms, and genetic ancestry in the Uruguayan population. Samples of saliva or peripheral blood were collected from 190 unrelated individuals from two regions of Uruguay, genotypes for polymorphic sites in a fragment within the LCT enhancer were determined and allelic frequencies calculated in all of them. Data were collected on frequency of milk and dairy consumption and self-reported symptoms in a subsample of 153 individuals. Biparental and maternal ancestry was determined by analyzing individual ancestry markers and mitochondrial DNA. Twenty-nine percentage of individuals reported symptoms attributed to the ingestion of fresh milk, with abdominal pain, bloating and flatulence being the most frequent. European LP-associated allele T-13910 showed a frequency of 33%, while other LP-associated alleles like G-13915 and T-14011 were observed in very low frequencies. Associations between self-reported symptoms, fresh milk intake, and C/T-13910 genotype were statistically significant. No evidence of association between genetic ancestry and C/T-13910 was found, although individuals carrying one T-13910 allele appeared to have more European ancestry. In conclusion, the main polymorphism capable of predicting lactose intolerance in Uruguayans is C/T-13910, although more studies are required to unravel the relation between genotype and lactase activity, especially in heterozygotes.

Filogeografía de mitogenomas indígenas de Uruguay

Recientemente, diversos estudios sobre la población uruguaya han demostrado que está conformada por desiguales aportes de europeos, africanos y pueblos originarios, entre otros. El aporte indígena es mayor cuando se analiza la contribución por línea materna, aunque su origen étnico/geográfico no es claro, ni tampoco cuándo ni cómo llegaron los distintos grupos. Para aportar al conocimiento del poblamiento prehistórico e histórico del territorio y sus relaciones con otras poblaciones se analizan, por secuenciación masiva, 32 genomas mitocondriales completos (mitogenomas) de habitantes actuales del país, identificados previamente por sus regiones hipervariables como correspondientes a los cuatro haplogrupos principales de origen americano. Se determinaron siete nuevos subhaplogrupos (A2be, A2bf, B2an, C1d1h, C1b30, C1b31 y D1x), otro se redenominó (C1d1d - actual C1d1g) y se plantea la revisión de los criterios de asignación de B2b6 y D1g5. Se estimó la antigüedad de los subhaplogrupos nuevos, que varía entre 4554 y 11985 años, con la excepción de C1d1g, cuya edad fue estimada en 20736 años. Algunas secuencias pudieron ser vinculadas a distintos grupos étnicos o a diversas regiones geográficas, como Amazonia, Chaco, Pampa, o Andes. Se discuten las nuevas asignaciones desubhaplogrupos y las de algunos previamente definidos, así como su distribución geográfica y antigüedad, con relación al panorama general de América del Sur.

Ancestría genética y estratificación social en Montevideo, Uruguay

Diversos estudios genéticos han demostrado que la población uruguaya es trihíbrida, formada por europeo/mediterráneos, indígenas y africanos, cuyo aporte varía en distintas regiones del país. Pese a que Montevideo es la capital de la República, hay escasos estudios sobre los orígenes de su población, que pueden diferir de otras regiones. En este trabajo se propone indagar sobre estos orígenes a partir de información genética en una muestra derivada de una previamente publicada, profundizando en algunas características para determinar su posible influencia en la estimación de la ancestría. Se consideró una muestra de 269 mujeres (casos y controles de un estudio de cáncer de mama) en quienes se analizaron haplogrupos y secuencias de las regiones hipervariables del ADN mitocondrial (ADNmt) y marcadores individuales de ancestría (AIMs) del ADN nuclear. Se observó que había diferencias en los porcentajesde ancestría cuando se analizaban separadamente las personas que se atendían en el sistema público de salud en relación a las que lo hacían en el sistema mutual, con diferencias significativas para el aporte indígena y el europeo/mediterráneo. Luego de corregidos los valores por lugar de atención de salud, se estimaron los siguientes aportes: 24.6% indígena, 67,7% europeo/mediterráneo y 7,7% africano para herencia materna, y de 11,1% indígena, 81,4% europeo/mediterráneo, y 7,5% africano para la herencia biparental. Se analizaron particularmente los aportes indígena y africano y se discutieron los resultados con relación a otros estudios. Debido a las diferencias encontradas relacionadas con la heterogeneidad de la población montevideana, se alerta sobre el muestreo y valores de referencia para estudios poblacionales futuros.

Genetic Admixture Analysis in the Population of Tacuarembó-Uruguay Using Alu Insertions

Tacuarembó is a department located in northeastern Uruguay, whose population is the result of several migration waves from Europe and Near East, as well as Africans and Afro-descents mostly from Brazil; these waves settled with the territory's various Native ethnic groups (Charrúa, Minuán, and Guaraní). In the past, this population has been the focus of genetic studies showing this trihybrid origin, with greater contributions of Natives and Africans than in other Uruguayan regions. In this study we analyzed eight Alu insertions (A25, ACE, APOA1, B65, D1, F13B, PV92, TPA25) to provide valuable information for ancestrality and genetic differentiation and to compare with both previous studies on the Tacuarembó population and Alu frequencies in other Uruguayan populations. The European contribution to Alu and classical markers was almost equal to that of a previous study using 22 classical markers (63% vs. 65%), while African contribution was higher (30% vs. 15%), and Native American contribution shows an important difference in Alu: 7% versus 20%. We found no significant differences in genetic differentiation between Tacuarembó and Montevideo but significant differences between Tacuarembó and Basque descendants from Trinidad. Our results support previous findings obtained with classical markers that demonstrate the trihybrid composition of the Tacuarembó population, correlated with historical records. Thus, Alu insertions provide interesting information in light of the admixture process in the Uruguayan population.

The transthyretin amyloidoses: advances in therapy

There are two forms of transthyretin (TTR) amyloidosis: non-hereditary and hereditary. The non-hereditary form (ATTRwt) is caused by native or wild-type TTR and was previously referred to as senile systemic amyloidosis. The hereditary form (ATTRm) is caused by variant TTR which results from a genetic mutation of TTR. The predominant effect of ATTRwt amyloidosis is on the heart, with patients having a greater left ventricular wall thickness at presentation than the devastating form which is light chain (AL) amyloidosis. ATTRm amyloidosis is broadly split into two categories: a type that predominantly affects the nervous system (often called familial amyloid polyneuropathy (FAP)) and one with a predilection for the heart (often called familial amyloid cardiomyopathy (FAC)). Approximately half of all TTR mutations known to express a clinical phenotype cause a cardiomyopathy. Since the introduction of orthotopic liver transplantation for ATTRm amyloidosis in 1991, several additional therapies have been developed. These therapies aim to provide a reduction or elimination of TTR from the plasma (through genetic approaches), stabilisation of the TTR molecule (to prevent deposition) and dissolution of the amyloid matrix. We describe the latest developments in these approaches to management, many of which are also applicable to wild-type amyloidosis.

Breast cancer risk and genetic ancestry: a case-control study in Uruguay

Background

Uruguay exhibits one of the highest rates of breast cancer in Latin America, similar to those of developed nations, the reasons for which are not completely understood. In this study we investigated the effect that ancestral background has on breast cancer susceptibility among Uruguayan women.

Methods

We carried out a case–control study of 328 (164 cases, 164 controls) women enrolled in public hospitals and private clinics across the country. We estimated ancestral proportions using a panel of nuclear and mitochondrial ancestry informative markers (AIMs) and tested their association with breast cancer risk.

Results

Nuclear individual ancestry in cases was (mean ± SD) 9.8 ± 7.6% African, 13.2 ± 10.2% Native American and 77.1 ± 13.1% European, and in controls 9.1 ± 7.5% African, 14.7 ± 11.2% Native American and 76.2 ± 14.2% European. There was no evidence of a difference in nuclear or mitochondrial ancestry between cases and controls. However, European mitochondrial haplogroup H was associated with breast cancer (OR = 2.0; 95% CI 1.1, 3.5).

Conclusions

We have not found evidence that overall genetic ancestry differs between breast cancer patients and controls in Uruguay but we detected an association of the disease with a European mitochondrial lineage, which warrants further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12905-015-0171-8) contains supplementary material, which is available to authorized users.

Questioning the "melting pot": analysis of Alu inserts in three population samples from Uruguay

The way that immigrants integrate into recipient societies has been discussed for decades, mainly from the perspective of the social sciences. Uruguay, as other American countries, received diffferent waves of European immigrants, although the details of the process of assimilation, when it did occur, are unclear. In this study we used genetic markers to understand the process experienced by the Basques, one of the major migration waves that populated Uruguay, and their relation to other immigrants, as well as to Native American and African descendants. For this purpose, we analyzed the allele frequencies of 10 ALU loci (A25, ACE, APOA1, B65, D1, F13B, PV92, TPA25, HS2.43, and HS4.65) in three samples from Uruguay (two of Basque descendants, one of non-Basque descendants) from two locations: Montevideo and Trinidad. No departure from Hardy-Weinberg expectations was observed, with the exceptions of the APOA1 and D1 loci in the non-Basque descendants' samples. Our data show that the major genetic contribution in the three samples comes from Europe (78-88%), with minor African (10-15%) and Native American (0-10%) contributions. Genetic distances reveal that Basque descendants from Trinidad cluster with Europeans, whereas both Montevideo samples cluster together and are separate from other populations, showing two diffferent types of integration, related to the general characteristics of each regional population.

Mitochondrial DNA in Basque descendants from the city of Trinidad, Uruguay: Uruguayan- or Basque-like population?

Like other countries in the Americas, during its colonization Uruguay was the recipient of immigrants from several ethnic groups from Europe, as well as of enslaved Africans. After its independence in 1830, Basques were the first group of Europeans to arrive in the country. In this paper, we aim to contribute to the understanding of the process of integration of these migratory waves into the Uruguayan society. For that purpose, individuals of Basque origin from the city of Trinidad, Uruguay, were chosen to participate in this study. Particularly, we wanted to determine if Basque descendants in Uruguay remained relatively isolated or if they mixed with other ethnic groups. Mitochondrial DNA (mtDNA) of 60 self-identified Basque descendants, taken from a larger sample of subjects with Basque ancestors, was analyzed. The origin of mtDNA haplogroups was 77.8% European, 20.4% Amerindian, and 1.8% African, showing similar frequencies to other Uruguayan regions. Very few sequences showed a clear Basque origin, although other sources such as the Canary Islands are likely. Moreover, genetic distances clearly show that Basque descendants are genetically closer to other Uruguayan groups than to European populations, including Basques. It is possible to conclude that Basques and their descendants in the region of Trinidad did not remain isolated and that their marriage behavior was similar to that of other Uruguayan populations. However, to have a more accurate picture of the way Basques intermarried with other populations in Uruguay, new analyses are needed that take into account paternal lineages as well as biparental genetic markers.

Experience journals: using computers to share personal stories about illness and medical intervention

Medical advances make it increasingly possible for children with previously fatal illness to live and thrive. However, a significant number still experience repeated operations, hospitalization, and invasive procedures, or need special care at home. Many do so with little or no intervention to help them and their families cope with the emotional stresses involved. One significant source of emotional and cognitive support is the community of patients and families who have experienced similar medical procedures. However, in spite of a general willingness to share experiences, communication among patients and families is usually limited. To facilitate this process, we are investigating the use of computer technology to record, organize, and display stories about the experiences of families with children who have been treated for cardiac and neurological illness at Children's Hospital, Boston. We are asking children and their families to record text and multimedia vignettes describing some aspect of their illness, coping strategies, or care that might be useful to others. These contributions will be available for browsing at a secure World-Wide-Web site. However, economic realities preclude reliance on a professional site administrator to organize and monitor what we hope to be a rapidly growing Web site with a large, distributed authorship. The need to make the Web site fully accessible to users who have varying familiarity with computers and Web browsing imposes further constraints. We are therefore developing software to automate the process of managing and organizing an easily accessed Web site that contains an "Experience Journal." We describe this software, the rationale for its development, and our plans for its use in the coming year.

Receptors for platelet derived growth factor in human glioma cell lines and influence of suramin on cell proliferation

A panel of 11 established human glioma cell lines was used to evaluate PDGF receptor binding using radioiodinated biosynthetic PDGF-AA and PDGF-AB as primary ligands. It was found that PDGF-receptor-binding was qualitatively heterogeneous. The affinities for PDGF-AA as well as PDGF-AB binding were within a close range of 0.13-0.33 nM and 0.16-1.1 nM, respectively. The number of binding sites per cell ranged between 56.000 and 250.000 for PDGF-AA and 72.000 to 300.000 for PDGF-AB. Two lines had only background levels of PDGF-AA binding. PDGF-AB binding was the dominant binding component in all but one cell line. In seven cell lines there were two binding components upon saturation analysis consisting of a high affinity component and a non-saturable low affinity component. PDGF and PDGF-receptors are suspected to be part of an autocrine loop in gliomas. Therefore, the effect of suramin on cell proliferation in serumfree cultures was tested in the same cell lines using doses of 25,200 or 500 micrograms/ml. It was found that the response to suramin was variable and that two cell lines still reached 2.8 fold and 4.5 fold their initial cell density even in the presence of 500 micrograms/ml whereas all other cells were completely arrested. Analyzing the response to 200 micrograms/ml it became evident, that the PDGF binding characteristics are of no reliable predictive value in respect to the efficacy of suramin.

The treatment of late post-traumatic orbital deformities

Trauma to the orbital region may result in fractures of the bony orbit, displacement of which gives rise to malposition of the eye and diplopia. If initial treatment is not feasible or is unsuccessful, later correction may be achieved by osteotomy or reduction and stabilisation of the bony fragments, often with bone grafts. Displaced medial or lateral canthi may need to be repositioned, where feasible in an overcorrected position. Where bone grafts are necessary, the skull is now favoured as the best donor site.

Proteinase activity in malignant human breast cancers and NMU mammary tumours of the rat

In subcellular fractions of human mammary tumours and NMU tumours of rats proteinase activity was studied by means of the synthetic substrates Bz-dl-arginin-4-nitroanilid (BAPNA) and Bz-dl-arginin-2-naphthyl-amid (BANA). Using the substrate BAPNA enzymatic activity was found to be highest in low speed particulate fractions, whereas in NMU tumours of rats the bulk of the activities could be observed in the high speed supernatant. The substrates BAPNA and BANA were cleavaged enzymatically in human mammary tumours at pH 7 and pH 6, respectively, while in rats the maximum turnover of both substrates changed at value of pH 6.5. Enzyme activity with BAPNA was proved to be resistant to alkaline preincubation in human breast cancer tissue only. On the other hand, the enzymatic cleavage of BANA was completely lost in human as well as in rat tumour specimens under these experimental conditions. It can be concluded from these results that both enzyme activities measured in human malignant mammary tumours, which are known for their invading activity, represent two different proteolytic enzymes with their maximum activity at neutral and acidic pH. Similar enzyme activities are quite different in NMU tumours, which are not invasive.

[restoration of duodenal passage in severe postoperative syndrome after surgery for gastro-duodenal ulcers. Experience with 40 cases (author's transl)]

The authors analyse 40 cases of restoration of duodenal passage for severe functional sequelae after surgery for duodenal ulcer. The type of reoperation depended upon the initial operation and thus after gastric resection with gastro-jejunal anastomosis, 26 procedures involving transposition of the efferent loop to the duodenum (Soupault-Bucaille operation) were performed, 8 conversions of a gastro-jejunal anastomosis to a gastro-duodenal anastomosis and one interposition of a small intestinal loop according to the technique of Henley. After gastro-enterostomy with or without vagotomy, 3 gastric resections with gastro-duodenal anastomosis were performed, and one replacement of a gastro-enterostomy, by a pyloroplasty. Operative mortality was 3/40 cases and long term results proved to be good in 80% of the patients.

Clinical pharmacological aspects of drug toxicity testing

Drugs are xenobiotics. Absorption, distribution, and elimination depend on their physico-chemical character. Lipophilic drugs are usually inactivated or activated by biotransformation systems. Nearly all metabolic pathways are influenced by drugs. Damage of the DNA includes the possible risk of mutation and inducton of cancer. Severe side-effects of drugs and some drug disasters in the past promoted physicians and legislators to elaborate new guidelines for the safety of drugs for human beings. The different requirements of the guidelines are compared using oral contraceptives as example. The problem in studies of drug metabolism in drug safety evaluation is to find out a species in which drug disposition is nearly identical to that in man, because the rat and the mouse are poor predictors of the human situation. In the future, extensive studies on comparative drug metabolism need to be done. The increasing number of hepatic adenomas and neoplasmas in the past ten years in women taking oral contraceptives initiated studies on metabolism of estrogens. Hydroxylation of ethinylestradiol at C 2 has been shown to be the key to understand the activation to arene oxides which bind covalently to nucleic acids and proteins. This metabolic pathway may explain the potential toxicity and cancerogenicity. This example should stress that drug metabolism is part of drug safety evaluation.

[Seroepidemiologic studies on reovirus infections of man, domestic and wild animals in Tanzania (author's transl)]

2238 sera of bovines, 95 of goats, 251 of antelopes (various species), 143 of zebras and 11 of warthogs collected in Tanzania as well as 811 sera of men and females of the city and the region of Dar es Salaam were tested for haemagglutination inhibiting antibodies (Ab) to reovirus serotypes (St) 1, 2 and 3. Ab to St 1 resp. 2 could be detected in 24--39% of bovines, goats, antelopes and zebras, and in warthogs to 64%. In human beings the positive percentage was 60%. Ab to St 3 were most prevalent: Sera of domestic animals were positive in 70--84%, of wild animals in 77--100% and of the human population in 91%. These figures include the occurrence of Ab to one St alone as well as to more than one St. A further analysis showed, that Ab to St 3 are definitely dominant especially in sera of animals, whereas the simultaneous occurrence of Ab to all 3 St was more frequently observed in sera of human beings. Other Ab-type combinations were apparently of far less importance. It seems to be significant that the highest infection rate was found in humans (except zebras and warthogs) and that their contact to animals did not result in a higher Ab conversion rate as without such a possibility. The results were discussed under seroepidemiologic aspects and it is concluded that reovirus infections are facultative viral zoonoses.

Dizepam metabolism in human foetal and adult liver

Diazepam was metabolized by human foetal liver microsomes to N-desmethyldiazepam and N-methyloxazepam as early as the 13th week of gestation. The metabolic activity was lower than that of microsomes from adult human liver. Diazepam was shown mainly to be hydroxylated to N-methyloxazepam at substrate concentrations higher than 0.1 mM. Diazepam levels above 1.0 mM were inhibitory to the overall metabolic reaction. SKF 525-A inhibited diazepam metabolism by foetal liver microsomes at a concentration of 0.1 mM. The addition of diazepam to foetal and adult human liver microsomes resulted in a type II spectral change. Its inhibition by carbon monoxide indicated that biotransformation of diazepam was performed by the cytochrome P-450-linked mono-oxygenase system.

[Pharmacokinetics in liver cirrhosis]

In patients with severe hepatic parenchymal damage drug metabolism is presumably impaired. The reduced detoxification can not be sufficiently described in the postulated multicompartment model by determination of plasma half-life, because it depends on the physicochemical properties of the drugs. An increase of dihydroxybilic acids inhibits drug metabolism. Some drugs and also its metabolites formed in the liver induce hepatic cell injury including necrosis and therefore they are contraindicated in patients suffering from liver disease.