CkP1 bacteriophage, a S16-like myovirus that recognizes Citrobacter koseri lipopolysaccharide through its long tail fibers

Citrobacter koseri is an emerging Gram-negative bacterial pathogen, which causes urinary tract infections. We isolated and characterized a novel S16-like myovirus CKP1 (vB_CkoM_CkP1), infecting C. koseri. CkP1 has a host range covering the whole C. koseri species, i.e., all strains that were tested, but does not infect other species. Its linear 168,463-bp genome contains 291 coding sequences, sharing sequence similarity with the Salmonella phage S16. Based on surface plasmon resonance and recombinant green florescence protein fusions, the tail fiber (gp267) was shown to decorate C. koseri cells, binding with a nanomolar affinity, without the need of accessory proteins. Both phage and the tail fiber specifically bind to bacterial cells by the lipopolysaccharide polymer. We further demonstrate that CkP1 is highly stable towards different environmental conditions of pH and temperatures and is able to control C. koseri cells in urine samples. Altogether, CkP1 features optimal in vitro characteristics to be used both as a control and detection agent towards drug-resistant C. koseri infections. KEY POINTS: • CkP1 infects all C. koseri strains tested • CkP1 recognizes C. koseri lipopolysaccharide through its long tail fiber • Both phage CkP1 and its tail fiber can be used to treat or detect C. koseri pathogens.

Genomic Analysis of Two Novel Bacteriophages Infecting Aci-netobacter beijerinckii and halotolerans Species

Bacteriophages are the most diverse genetic entities on Earth. In this study, two novel bacteriophages, nACB1 (Podoviridae morphotype) and nACB2 (Myoviridae morphotype), which infect Acinetobacter beijerinckii and Acinetobacter halotolerans, respectively, were isolated from sewage samples. The genome sequences of nACB1 and nACB2 revealed that their genome sizes were 80,310 bp and 136,560 bp, respectively. Comparative analysis showed that both genomes are novel members of the Schitoviridae and the Ackermannviridae families, sharing ≤ 40% overall nucleotide identities with any other phages. Interestingly, among other genetic features, nACB1 encoded a very large RNA polymerase, while nACB2 displayed three putative depolymerases (two capsular depolymerases and one capsular esterase) encoded in tandem. This is the first report of phages infecting A. halotolerans and beijerinckii human pathogenic species. The findings regarding these two phages will allow us to further explore phage—Acinetobacter interactions and the genetic evolution for this group of phages.

Genomic Diversity of Bacteriophages Infecting the Genus Acinetobacter

The number of sequenced Acinetobacter phage genomes in the International Nucleotide Sequence Database Collaboration has increased significantly in recent years, from 37 in 2017 to a total of 139 as of January 2021 with genome sizes ranging from 31 to 378 kb. Here, we explored the genetic diversity of the Acinetobacter phages using comparative genomics approaches that included assessment of nucleotide similarity, shared gene content, single gene phylogeny, and the network-based classification tool vConTACT2. Phages infecting Acinetobacter sp. are genetically diverse and can be grouped into 8 clusters (subfamilies) and 46 sub-clusters (genera), of which 8 represent genomic singletons (additional genera). We propose the creation of five new subfamilies and suggest a reorganisation of the genus Obolenskvirus. These results provide an updated view of the viruses infecting Acinetobacter species, providing insights into their diversity.

Analysis of NIS Plasma Membrane Interactors Discloses Key Regulation by a SRC/RAC1/PAK1/PIP5K/EZRIN Pathway with Potential Implications for Radioiodine Re-Sensitization Therapy in Thyroid Cancer

The functional expression of the sodium-iodide symporter (NIS) at the membrane of differentiated thyroid cancer (DTC) cells is the cornerstone for the use of radioiodine (RAI) therapy in these malignancies. However, NIS gene expression is frequently downregulated in malignant thyroid tissue, and 30% to 50% of metastatic DTCs become refractory to RAI treatment, which dramatically decreases patient survival. Several strategies have been attempted to increase the NIS mRNA levels in refractory DTC cells, so as to re-sensitize refractory tumors to RAI. However, there are many RAI-refractory DTCs in which the NIS mRNA and protein levels are relatively abundant but only reduced levels of iodide uptake are detected, suggesting a posttranslational failure in the delivery of NIS to the plasma membrane (PM), or an impaired residency at the PM. Because little is known about the molecules and pathways regulating NIS delivery to, and residency at, the PM of thyroid cells, we here employed an intact-cell labeling/immunoprecipitation methodology to selectively purify NIS-containing macromolecular complexes from the PM. Using mass spectrometry, we characterized and compared the composition of NIS PM complexes to that of NIS complexes isolated from whole cell (WC) lysates. Applying gene ontology analysis to the obtained MS data, we found that while both the PM-NIS and WC-NIS datasets had in common a considerable number of proteins involved in vesicle transport and protein trafficking, the NIS PM complexes were particularly enriched in proteins associated with the regulation of the actin cytoskeleton. Through a systematic validation of the detected interactions by co-immunoprecipitation and Western blot, followed by the biochemical and functional characterization of the contribution of each interactor to NIS PM residency and iodide uptake, we were able to identify a pathway by which the PM localization and function of NIS depends on its binding to SRC kinase, which leads to the recruitment and activation of the small GTPase RAC1. RAC1 signals through PAK1 and PIP5K to promote ARP2/3-mediated actin polymerization, and the recruitment and binding of the actin anchoring protein EZRIN to NIS, promoting its residency and function at the PM of normal and TC cells. Besides providing novel insights into the regulation of NIS localization and function at the PM of TC cells, our results open new venues for therapeutic intervention in TC, namely the possibility of modulating abnormal SRC signaling in refractory TC from a proliferative/invasive effect to the re-sensitization of these tumors to RAI therapy by inducing NIS retention at the PM.

Unpuzzling Friunavirus-Host Interactions One Piece at a Time: Phage Recognizes Acinetobacter pittii via a New K38 Capsule Depolymerase

Acinetobacter pittii is a species that belong to the Acinetobacter calcoaceticus-baumannii complex, increasingly recognized as major nosocomial bacterial pathogens, often associated with multiple drug-resistances. The capsule surrounding the bacteria represents a main virulence factor, helping cells avoid phage predation and host immunity. Accordingly, a better understanding of the phage infection mechanisms is required to efficiently develop phage therapy against Acinetobacter of different capsular types. Here, we report the isolation of the novel A. pittii-infecting Fri1-like phage vB_Api_3043-K38 (3043-K38) of the Podoviridae morphotype, from sewage samples. Its 41,580 bp linear double-stranded DNA genome harbours 53 open reading frames and 302 bp of terminal repeats. We show that all studied Acinetobacter Fri1-like viruses have highly similar genomes, which differentiate only at the genes coding for tailspike, likely to adapt to different host receptors. The isolated phage 3043-K38 specifically recognizes an untapped Acinetobacter K38 capsule type via a novel tailspike with K38 depolymerase activity. The recombinant K38 depolymerase region of the tailspike (center-end region) forms a thermostable trimer, and quickly degrades capsules. When the K38 depolymerase is applied to the cells, it makes them resistant to phage predation. Interestingly, while K38 depolymerase treatments do not synergize with antibiotics, it makes bacterial cells highly susceptible to the host serum complement. In summary, we characterized a novel phage-encoded K38 depolymerase, which not only advances our understanding of phage-host interactions, but could also be further explored as a new antibacterial agent against drug-resistant Acinetobacter.

Genome-wide association study of resistance/susceptibility to infectious bovine keratoconjunctivitis in Brazilian Hereford cattle

Genome-wide association studies were conducted to identify the more informative genomic regions and SNPs, as well as to identify candidate genes associated with infectious bovine keratoconjunctivitis (IBK) resistance/susceptibility in Hereford cattle. A Bayes B statistical approach was initially applied in genome-wide association studies by using deregressed estimated breeding values for IBK resistance/susceptibility. To estimate the combined effect of a genomic region that is potentially associated with QTL, 2504 non-overlapping 1-Mb windows that varied in SNP number were defined, with the most informative 24 windows including 427 SNPs and explaining more than 20% of the estimated genetic variance for IBK resistance/susceptibility. These regions were explored with respect to their biological functions through functional analysis to map potential candidate genes. The significant SNPs were mapped on chromosomes 1, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 18, 20, 23, and 28, and candidate genes were detected as related to the IBK. Most informative SNPs in term of genetic variance were located in proximity of genes related to phenotypic expression of lesions and biological processes associated to the IBK. Knowledge about phenotypic and genomic variation generated in the present study can be used to on design selection strategies to improve the resistance to IBK of Hereford cattle herds.

Hyperparathyroidism-Jaw Tumor Syndrome in a Patient With Colon Cancer: A Case Report

Background: Hyperparathyroidism-jaw tumor syndrome (HPT-JT) is a rare autosomal dominant disease, caused by mutations in the CDC73 gene, characterized by parathyroid tumors in association with fibro-osseous lesions of the mandible or maxilla. The occurrence of renal cysts or tumors, uterine and thyroid tumors has been reported. The association with other neoplastic lesions has been described, but its meaning and frequency are not well established. Clinical Case: A 48-year-old Roma woman was admitted to our hospital due to severe abdominal pain and constipation. She had a past history of kidney stones with several episodes of acute renal colic and had been recently diagnosed with colon cancer. Her family history was positive for colon cancer. Disease staging suggested the presence of liver metastases and multiple lytic lesions of the axial skeleton, pelvis and femurs. Laboratory investigation disclosed high calcium levels (15 mg/dL) and cancer associated hypercalcemia was suspected. However, PTH was markedly elevated (2979 pg/mL), in favor of a parathormone dependent cause. Further imaging procedures showed a heterogeneous mass, posterior to the right thyroid lobe and bone lesions on the left mandible, likely to correspond to brown tumors. Once the hypercalcemia was controlled, she was submitted to parathyroidectomy and right thyroid lobectomy plus sigmoidectomy and liver biopsy. The histology revealed an atypical parathyroid adenoma with 3,5 cm and papillary thyroid cancer with 1,2 cm, as well as colon adenocarcinoma metastatic to the liver. Postoperatively, the patient developed a hungry bone syndrome needing adequate treatment. Two months after surgery, the patient initiated chemotherapy for colon cancer. Screening for germline mutations in the CDC73 gene (formerly HRPT2) was positive for a deletion (c.765_766delTG/p.Val256LysX10). Conclusions: Hypercalcemia in a patient with malignant disease may be independent of malignancy. In the patient presented herein her past history of kidney stones and the involvement of the mandible were highly suggestive of HPT-JT. Missing the diagnosis would negatively impact in the patient′s prognosis and in the management of her family. Further clinical and genetic studies are ongoing trying to clarify whether the patient has two inherited conditions or a phenotype of HPT-JT including colon cancer.

Heath care utilization after birth in Brazil: a national study

Background

The Brazilian Ministry of Health recommends primary health care actions for women and babies in the first week after birth, with the aim of monitoring health status, screening for diseases, vaccination, support for breastfeeding and promoting contraception. However, data on these actions are not available at the national level. This study aims to estimate the use of outpatient health services in the postpartum period and to verify the demographic, socioeconomic and obstetric factors associated with this use.

Methods

National hospital-based study, conducted in 2011-2012, with an interview of 23,894 women. Estimates were calculated for eight indicators of health service use with performance assessed as “satisfactory” (75-100%), “partial” (50-74%) and “unsatisfactory” (<50%). Multiple logistic regression was performed to verify the association between women's characteristics and each of the analyzed indicators.

Results

”Demand for postpartum consultation” (73.9%; 95% CI: 72.4-75.3%), “demand for newborn consultation” (91.6%; 95% CI: 90.6% - 92.5%), “BCG vaccination” (99.0%; 95% CI 98.7% - 99.2%) and “Hepatitis B vaccination” (96.8%; 95% CI 96.0%-97.5%) were considered satisfactory. “Neonatal screening test in the first week of life” was considered partial (60.1%; 95% CI 57.6% - 62.6%), while “consultation of the woman in the first 15 days after delivery” (37.0% 95% CI 35.0-39.0%),”consultation of the newborn in the first seven days of life”(21.8% 95% CI 20.2% - 23.5%) and “receiving the result of neonatal screening in the first month of life” (29.8% CI 95% 27.6%-32.2%) were considered unsatisfactory. Regional and social inequalities were identified, with the worst performance of all indicators in the less developed North and Northeast regions and in the most vulnerable women.

Conclusions

There is a need for better organization and provision of services, aiming to increase the coverage of postpartum and childcare actions and to reduce health inequalities.

Key messages

Low coverage of postnatal actions limits access to effective health care practices, putting mothers and babies at greater risk of illness and death. Regional and social inequalities and worse performance of health actions that depend exclusively on primary care services suggest barriers to access and failures in the organization of services.

Unsafe abortion in Brazil: a systematic review

Background

In Brazil, abortion is legally allowed in cases of risk to the woman's life, pregnancy resulting from rape and cases of fetal anencephaly. Despite the restrictive legislation, studies estimated that around 1 million abortions took place in the country in 2005. Abortions occurred regardless of womeńs socioeconomic position, race, age and religion, but unsafe practices were more common among young women, with low educational levels, single, students or domestic workers. This study sought to update knowledge on unsafe abortion in Brazil.

Methods

We carried out a systematic review with study search on Medline and LILACS, with no language restriction, from 2008 to 2018. We evaluated article quality using the Joanna Briggs Institute instruments. We evaluated 50 articles.

Results

There was a decrease in the ratio of induced abortions by 1,000 women of reproductive age reaching 16 per 1,000 in 2013. However, direct estimates do not indicate a decrease in the prevalence of induced abortion, estimated to be 13% in 2016. Higher prevalences were observed in more socially vulnerable populations. Half of all women reported using medications for terminating pregnancies and the number of hospital admissions due to complications from abortion decreased from 1992 to 2009. Maternal morbimortality from abortion had a reduced frequency but it is likely that maternal deaths from abortion are under-reported.

Conclusions

Abortion is frequently used in Brazil, especially in less-developed regions and by more socially-vulnerable women. Access to safer methods probably contributed to the reduction of complications, hospitalizations and morbimortality from abortion. However, half of all women still used other unsafe methods and the number of admissions due to complications from abortion is still high. The small scientific production and lack of methodological adequacy led to the development of a special issue on Abortion in Brazil in the jornal Reports in Public Health.

Key messages

Restrictive legislation does not prevent abortion, but limits access to safe abortion and makes it diffiult to prevent morbidity and mortaliity from abortion. Restrictive legislation and the stigma associated with abortion make studies difficult to estimate the rates, complications and factors associated with abortion.

TNFα-mediated activation of NF-κB downregulates sodium-iodide symporter expression in thyroid cells

The sodium-iodide symporter (NIS) mediates transport of iodide across the basolateral membrane of thyroid cells. NIS expression in thyroid cancer (TC) cells allows the use of radioactive iodine (RAI) as a diagnostic and therapeutic tool, being RAI therapy the systemic treatment of choice for metastatic disease. Still, a significant proportion of patients with advanced TC lose the ability to respond to RAI therapy and no effective alternative therapies are available. Defective NIS expression is the main reason for impaired iodide uptake in TC and NIS downregulation has been associated with several pathways linked to malignant transformation. NF-κB signaling is one of the pathways associated with TC. Interestingly, NIS expression can be negatively regulated by TNF-α, a bona fide activator of NF-κB with a central role in thyroid autoimmunity. This prompted us to clarify NF-kB’s role in this process. We confirmed that TNF-α leads to downregulation of TSH-induced NIS expression in non-neoplastic thyroid follicular cell-derived models. Notably, a similar effect was observed when NF-κB activation was triggered independently of ligand-receptor specificity, using phorbol-myristate-acetate (PMA). TNF-α and PMA downregulation of NIS expression was reverted when NF-κB-dependent transcription was blocked, demonstrating the requirement for NF-kB activity. Additionally, TNF-α and PMA were shown to have a negative impact on TSH-induced iodide uptake, consistent with the observed transcriptional downregulation of NIS. Our data support the involvement of NF-κB-directed transcription in the modulation of NIS expression, where up- or down-regulation of NIS depends on the combined output to NF-κB of several converging pathways. A better understanding of the mechanisms underlying NIS expression in the context of normal thyroid physiology may guide the development of pharmacological strategies to increase the efficiency of iodide uptake. Such strategies would be extremely useful in improving the response to RAI therapy in refractory-TC.

Saccharomyces cerevisiae (YT001) supplementation for the control of Haemonchus contortus and modulation of the immune response of sheep

Studies aiming at the development and evaluation of alternative methods to minimise losses caused by the gastrointestinal nematode Haemonchus contortus are extremely important. Such research is essential, given the high morbidity rates among sheep and the significant mortality rates of lambs, allied to the low efficacy of commercial products for the control of this parasite. The purpose of this study was to evaluate the effect of the Saccharomyces cerevisiae (YT001 - YEASTECH) on the control of H. contortus and its modulation of the immune response in experimentally infected sheep. Eighteen sheep were divided into two groups. Group 1, the control group, comprised animals infected with H. contortus and supplemented with distilled water, while Group 2, the treated group, consisted of animals infected and supplemented with S. cerevisiae (400 million cfu/day of suspension for 49 days). The following parasitological parameters were evaluated: number of eggs per gram of faeces, number of infective larvae (L3) recovered per faecal culture, and parasitic load of the abomasum. The following immunological parameters were quantified: immunoglobulin (Ig)A in the mucous secretions and serum IgG; cytokines interleukin (IL)-4, IL-5 and IL-10; number of eosinophils in the abomasal mucosa and groups of cells positive for the markers: MHCII, CD4⁺CD25⁺, CD5⁺CD8⁺, WC4, CD5⁺CD4⁺, CD8⁺CD11b⁺ and CD5⁺WC1 by whole blood flow cytometry. The results revealed a significant decrease (P<0.05) in the number of larvae and significantly higher serum IgG levels (P<0.05) in the group supplemented with S. cerevisiae. The supplemented animals showed significantly larger numbers of eosinophils (P<0.05), as well as more cells positive for MHCII, CD4⁺CD25⁺, CD5⁺CD8⁺ than the control animals. This study confirmed the beneficial action of S. cerevisiae on the host immune response to H. contortus, as evidenced mainly by the smaller number of L3 recovered from the faeces of sheep supplemented with S. cerevisiae.

Antagonistic effects of RAC1 and tumor-related RAC1b on NIS expression in thyroid

Thyroid cancer (TC) is the most common endocrine malignancy. The sodium-iodide symporter (NIS), responsible for active transport of iodide into thyroid cells, allows the use of radioactive iodine (RAI) as the systemic treatment of choice for TC metastatic disease. Still, patients with advanced forms of TC often lose the ability to respond to RAI therapy, which results in worse survival rates. We have shown that the overexpression of RAC1b, a tumor-related RAC1 splice variant, is associated with less favorable clinical outcomes in differentiated TCs derived from the follicular epithelial (DTCs). RAC1b overexpression is also significantly associated with the presence of MAPK-activating BRAFV600E mutation, which has been previously implicated in the loss of NIS expression. Here, we show that increased RAC1b levels are associated with NIS downregulation in DTCs and demonstrate that ectopic overexpression of RAC1b in non-transformed thyroid cells is sufficient to decrease TSH-induced NIS expression, antagonizing the positive effect of the canonically spliced RAC1 GTPase. Moreover, we clearly document for the first time in thyroid cells that both NIS expression and iodide uptake are hampered by RAC1 inhibition, highlighting the role of RAC1 in promoting TSH-induced NIS expression. Our findings support a role for RAC1 and RAC1b signaling in the regulation of NIS expression in thyroid cells and suggest that RAC1b in cooperation with other cancer-associated signaling cues may be implicated in the response of DTCs to RAI therapy.

Lichen planus: altered AIM2 and NLRP1 expression in skin lesions and defective activation in peripheral blood mononuclear cells

BACKGROUND

Lichen planus (LP) is an inflammatory skin disease with unknown aetiology. Activation by pathogen-associated molecular patterns or environmental stimuli may activate some components of inflammasomes that contribute to the inflammatory process in LP lesions.

AIM

To characterize the inflammasomes in skin lesions and peripheral blood mononuclear cells (PBMCs) of patients with LP under Toll-like receptor (TLR) activation.

METHODS

In total, 15 patients with LP and 14 healthy controls (HCs) were enrolled in the study. Inflammasome expression in skin was evaluated by real-time PCR and immunohistochemistry, while ELISA was used to assess the production of interleukin (IL)-1β by PBMCs under stimulation with TLR4 and TLR7/TLR8 agonists and adenosine triphosphate (ATP).

RESULTS

Compared with the levels in HC samples, increased expression of the inflammasome AIM2 was verified in both epidermal and dermal sections of LP skin lesions, whereas NLRP1 and IL-β expression levels were enhanced in the dermis. LP skin lesion samples exhibited higher AIM2 transcript levels, similar NLRP1 levels and lower pro-IL-1β mRNA levels compared with HC samples. We verified that, compared with PBMCs from HC subjects, PBMCs from patients with LP produced similar amounts of IL-1β after induction by TLR4 agonists but lower IL-1β levels after induction by TLR7/TLR8 agonists, regardless of the addition of ATP.

CONCLUSION

Alterations in innate immunity, such as inflammasome component expression in skin lesions and PBMCs, were observed in patients with LP. Further investigations of dysfunctional inflammasome activation and the chronic inflammatory status of LP are required.

Homozygous Calcium-Sensing Receptor Polymorphism R544Q Presents as Hypocalcemic Hypoparathyroidism

CONTEXT

Autosomal dominant hypocalcemia type 1 (ADH1) is caused by heterozygous activating mutations in the calcium-sensing receptor gene (CASR). Whether polymorphisms that are benign in the heterozygous state pathologically alter receptor function in the homozygous state is unknown.

OBJECTIVE

To identify the genetic defect in an adolescent female with a history of surgery for bilateral cataracts and seizures. The patient has hypocalcemia, hyperphosphatemia, and low serum PTH level. The parents of the proband are healthy.

METHODS

Mutation testing of PTH, GNA11, GCM2, and CASR was done on leukocyte DNA of the proband. Functional analysis in transfected cells was conducted on the gene variant identified. Public single nucleotide polymorphism (SNP) databases were searched for the presence of the variant allele.

RESULTS

No mutations were identified in PTH, GNA11, and GCM2 in the proband. However, a germline homozygous variant (c.1631G>A; p.R544Q) in exon 6 of the CASR was identified. Both parents are heterozygous for the variant. The variant allele frequency was near 0.1% in SNP databases. By in vitro functional analysis, the variant was significantly more potent in stimulating both the Ca2+i and MAPK signaling pathways than wild type when transfected alone (P < 0.05) but not when transfected together with wild type. The overactivity of the mutant CaSR is due to loss of a critical structural cation-π interaction.

CONCLUSIONS

The patient's hypoparathyroidism is due to homozygosity of a variant in the CASR that normally has weak or no phenotypic expression in heterozygosity. Although rare, this has important implications for genetic counseling and clinical management.

Novel Mutation in the CASR Gene (p.Leu123Ser) in a Case of Autosomal Dominant Hypocalcemia

Autosomal dominant hypocalcemia, caused by activating mutations of the calcium-sensing receptor (CASR) gene, is characterized by hypocalcemia with an inappropriately low concentration of parathyroid hormone (PTH). In this report, we describe the identification of a novel missense mutation in the CASR gene, in a boy with autosomal dominant hypocalcemia. Polymerase chain reaction (PCR)-single strand and DNA sequencing revealed a heterozygous mutation in CASR gene that causes a leucine substitution for serine at codon 123 (p.Leu123Ser). This mutation was absent in DNA from 50 control patients. In silico studies suggest that the identified variant was likely pathogenic. Sequencing analysis in the mother suggested mosaicism for the same variant, and she was clinically and biochemically unaffected. Clinical manifestations of the index case started with seizures at 14 months of age; cognitive impairment and several neuropsychological disabilities were noted during childhood. Extrapyramidal signs and basal ganglia calcification developed later, namely, hand tremor and rigidity at the age of 7 and 18 years, respectively. Laboratory analysis revealed hypocalcemia, hyperphosphatemia, and low-serum PTH with hypomagnesemia and mild hypercalciuria. After 2 years of treatment with calcium supplements and calcitriol, some brief periods of clinical improvement were reported; as well as an absence of nephrocalcinosis.

Uncommon association of cerebral meningioma, parathyroid adenoma and papillary thyroid carcinoma in a patient harbouring a rare germline variant in the CDKN1B gene

Multiple endocrine neoplasia type 4 (MEN 4) is a novel form of multiple endocrine neoplasia caused by mutations in the CDKN1B gene. Its clinical presentation includes MEN 1-related tumours such as parathyroid and anterior pituitary tumours in possible association with gonadal, adrenal, renal and thyroid tumours as well as facial angiofibromas, colagenomas and meningiomas. We describe the case of a patient with meningioma, papillary thyroid carcinoma, parathyroid adenoma and, additionally, Hürthle cell adenoma, cholesteatoma and uterine leiomyomas. Considering that this association could represent a MEN 4-like phenotype, we looked for germline mutations in the CDKN1B gene. A rare heterozygous single nucleotide substitution c.397C>A was identified. Its role as a susceptibility factor remains to be established.

Identification and characterization of two novel germline RET variants associated with medullary thyroid carcinoma

Activating germline mutations in the RET proto-oncogene are responsible for about 98 % of the familial forms of medullary thyroid carcinoma (MTC), which represent 25 % of all MTC cases. The search for germline mutations in this gene is important for the recognition of hereditary forms of MTC and further identification of at-risk relatives who may benefit from early clinical intervention. Genotype-phenotype correlations are well established for most disease-causing RET mutations, allowing risk stratification. The association of a new RET variant with the MTC phenotype and familial predisposition requires the assessment of its functional and clinical significance. The aim of this study was to evaluate the oncogenic potential of two newly identified RET germline variants associated with late-onset MTC. In vitro functional assays were designed to address the transforming potential of novel RET variants, through their expression in non-transformed cells, and comparing their effect with wild-type RET. The new variants were identified in codons 515 (p.C515W) and 636 (p.T636M) located, respectively, in exons 8 and 11, thus resulting in amino acid substitutions in the extracellular region of the tyrosine kinase receptor RET. Through functional assays, we observed increased cell growth and proliferation, loss of contact inhibition, and a stimulation of cell migration, suggesting that these new RET variants hold some relevant transforming potential. The transforming potential of these novel RET variants was of low-grade, when compared to that of RET MEN2A-causing mutation p.C634R, probably explaining the mild phenotype characterized by late onset and low clinical aggressiveness.

Molecular diagnosis of multiple endocrine neoplasia Type 2

Multiple endocrine neoplasia Type 2 is a rare familial cancer syndrome transmitted in an autosomal dominant manner. It is characterized by the association of medullary thyroid carcinoma with pheochromocytoma and hyperparathyroidism. Medullary thyroid carcinoma, present in virtually all patients, is the principal cause of death. In 1993, germline mutations in the RET proto-oncogene were identified as the underlying cause of the syndrome. Genetic screening of at-risk family members can now be performed with high specificity and sensitivity. The ability to determine gene carrier status at a preclinical stage is of great value as it allows early prophylactic thyroidectomy. The specific RET codon mutation correlates with clinical variants of the syndrome, age at onset and aggressiveness of medullary thyroid carcinoma. This review will focus on mutational spectrum, genotype-phenotype correlations and clinical decisions based on genetic information.

Genetic diversity of Vriesea cacuminis (Bromeliaceae): an endangered and endemic Brazilian species

Data about the genetic structure can help to understand the evolutionary process of natural populations as well as to drive strategies of conservation. Vriesea cacuminis, an endemic Brazilian Bromeliad, has been found in 2 areas of Minas Gerais State. One is a legal preservation unit (Ibitipoca State Park) and the other an unprotected area (Serra Negra). The 2 areas belong to the Mantiqueira Mountain Range Complex; both are characterized by steep relief with high altitudes and by heterogenic vegetation formed by a mosaic of rocky fields and forest fragments. According to International Union for Conservation of Nature criteria, V. cacuminis is designated as "vulnerable". We examined the genetic variability and population structure of 70 individuals (3 populations) of V. cacuminis, using 16 ISSR markers. Although V. cacuminis is considered a rare species, the estimated genetic diversity was found to be relatively high (Shannon index = 0.33; percentage of polymorphic bands = 87%). The populations were found not to be structured (AMOVA test, ΦST = 0.16), probably due to the cross-breeding. Based on Bayesian analysis, this species includes one cluster containing the populations from Ibitipoca State Park and another cluster including the population from Serra Negra. This information will help determine strategies to maintain the genetic variability of these populations.

Identification of three new variants of SDHx genes in a cohort of Portuguese patients with extra-adrenal paragangliomas

BACKGROUND

Extra-adrenal paragangliomas (PGL) are rare neoplasms occurring in sporadic and familial forms, the latter mostly in association with germline mutations of SD- HB, SDHC or SDHD genes.

AIM

Characterize frequency and spectrum of germline mutations among a cohort of Portuguese patients with extra-adrenal PGL.

DESIGN

Molecular and clinical data were reviewed on 44 patients referred for genetic testing by a single laboratory.

RESULTS

Genetic analysis identified 11 patients with head and neck PGL (30.6%) positive for SD- Hx gene mutations (6 SDHD, 4 SDHB, 1 SDHC) and 4 patients with abdominal or pelvic PGL (50%) positive for SDHx gene mutations (4 SDHB). Large deletions made up about 20% of the mutations detected. Mutation carriers were younger and more frequently had multiple or malignant PGL than patients without mutations. Only 11% of the head and neck PGL were secretory. In contrast, 100% of the abdominal or pelvic PGL were secretory. Five patients had a malignant PGL (4 SDHB, 1 apparently sporadic). Three novel mutations were identified: two in the SDHD gene (c.411delT [p.Leu139PhefsX29] and c.371_390del20insGG [p.Ala124_Ala130delinsGly]), one in the SDHB gene (c.49A>G [p.Thr17Ala]). The SDHD variant c.411delT [p.Leu139PhefsX29] was present in 3 apparently unrelated patients. Molecular genetic testing of 22 relatives disclosed 16 mutation carriers.

CONCLUSIONS

Genetic analysis identified 15 patients (34.1%) and 16 at-risk individuals (72.7%) positive for SDHx gene mutations. The finding of three novel mutations broadens the mutational profile of the mitochondrial complex II succinate dehydrogenase genes reported in other large European series of patients with paragangliomas. Further studies are needed to clarify whether the high frequency of the SDHD variant c.411delT [p.Leu139PhefsX29] corresponds to a founder mutation.

Identification of the first germline HRPT2 whole-gene deletion in a patient with primary hyperparathyroidism

OBJECTIVE

Germline mutations in the HRPT2 gene are associated with the hereditary hyperparathyroidism-jaw tumour syndrome (HPT-JT) and a subset of familial isolated hyperparathyroidism (FIHP). Somatic HRPT2 mutations are detected in sporadic parathyroid carcinomas and less frequently in cystic adenomas. The purpose of this study was to investigate the underlying HRPT2 defect in a young patient with symptomatic hyperparathyroidism due to an apparently sporadic parathyroid adenoma with cystic features.

DESIGN AND METHODS

HRPT2 mutations in the patient's genomic and parathyroid tumour DNA were screened by PCR-based sequencing. Tumour loss of heterozygosity (LOH) at the HRPT2 locus was assessed with microsatellite markers. A large germline HRPT2 deletion was investigated by real-time quantitative PCR analysis (qPCR). Genomic DNA losses were also appraised by chromosomal comparative genomic hybridization (cCGH).

RESULTS

No germline HRPT2 point mutation was detected by direct sequencing. A novel hemizygous HRPT2 somatic mutation (c.32delA) was identified in the tumour. Apparent constitutional homozygosity for HRPT2 flanking microsatellite markers, and absence of LOH at a distal marker, suggested a large germline deletion. Gene dose mapping by qPCR unveiled a de novo deletion of the whole HRPT2 gene and adjacent loci (<9·3 Mb in size). cCGH confirmed germline DNA loss involving the HRPT2 locus.

CONCLUSIONS

We report the first large germline deletion of the HRPT2 gene, which was not detectable by conventional PCR-based sequencing methods. This finding emphasizes that qPCR should be implemented in HRPT2 molecular analysis, which may improve genetic assessment and clinical management of patients with FIHP and HPT-JT.

Genetic variability of an endangered Bromeliaceae species (Pitcairnia albiflos) from the Brazilian Atlantic rainforest

Pitcairnia albiflos is a Bromeliaceae species endemic to Brazil that has been included as data-deficient in the extinction risk list of Brazilian flora. We analyzed genetic variability in P. albiflos populations using RAPD markers to investigate population structure and reproductive mechanisms and also to evaluate the actual extinction risk level of this species. Leaves of 56 individuals of P. albiflos from three populations were collected: Urca Hill (UH, 20 individuals), Chacrinha State Park (CSP, 24 individuals) and Tijuca National Park (TNP, 12 individuals). The RAPD technique was effective in characterizing the genetic diversity in the P. albiflos populations since it was possible to differentiate the populations and to identify exclusive bands for at least two of them. Even if there is low genetic diversity among them (CSP-UH = 0.463; CSP-TNP = 0.440; UH-TNP = 0.524), the populations seem to be isolated according to the low genetic diversity observed within them (H(pop) CSP = 0.060; H(pop) UH = 0.042; H(pop) TNP = 0.130). This fact might be the result of clonal and self-reproduction predominance and also from environmental degradation around the collection areas. Consequently, it would be important to protect all populations both in situ and ex situ to prevent the decrease of genetic variability. The low genetic variability among individuals of the same population confirms the inclusion of this species as critically endangered in the risk list for Brazilian flora.

Identification of de novo germline mutations in the HRPT2 gene in two apparently sporadic cases with challenging parathyroid tumor diagnoses

The diagnosis of parathyroid carcinomas is often difficult. HRPT2 mutations have been identified in familial [hyperparathyroidism-jaw tumor (HPT-JT) syndrome] and sporadic parathyroid carcinomas, supporting that HRPT2 mutations may confer a malignant potential to parathyroid tumors. In this study, we report the clinical, histopathological, and genetic investigation of two unrelated cases, whom had apparently sporadic malignant parathyroid tumors, initially diagnosed as adenomas. In one case, the differential diagnosis was complicated by cervical seeding of parathyroid tumor cells. Genetic studies identified de novo HRPT2 germline mutations in cases 1 (c.518_521delTGTC [p.Ser174LysfsX27]) and 2 (c.226 C > T [p.Arg76X]), unveiling the hereditary HPT-JT syndrome in both patients. Furthermore, the identification of somatic mutations in the patients‟ parathyroid tumors provided evidence for complete inactivation of the HRPT2 gene, which was consistent with the tumor malignant features. The sensitivity of parafibromin immunostaining to detect HRPT2 mutations was limited. The present data suggests that patients with apparently sporadic parathyroid carcinomas, or parathyroid tumors with atypical histological features, should undergo molecular genetic testing, as it may detect germline HRPT2 mutations. Establishing the diagnosis of hereditary HPT-JT syndrome is relevant for clinical counseling and management of the carriers and their relatives.

Genetic variability of Mahanarva sp (Hemiptera: Cercopidae) collected from different sites in Brazil

Spittlebugs are the leading cause of damage to tall grasses. Annual losses are estimated to reach 2.1 billion dollars in sugarcane crops and grazing land throughout the world. Correct identification of these species is difficult due to similarities in color, body size and male genitalia. Molecular markers have been useful in the identification and assessment of genetic diversity of many species. We investigated the genetic diversity of the spittlebug species Mahanarva fimbriolata, M. spectabilis and M. liturata and looked for markers that could aid in their identification. DNA from 34 spittlebug specimens, collected from six different regions of Brazil (Brasília, Campo Grande, Valença, Presidente Prudente, Juiz de Fora, and Porto Alegre), was analyzed with 29 RAPD primers, generating 501 polymorphic markers. High genetic variability was found among individuals M. fimbriolata (0.37), M. spectabilis (0.18) and M. liturata (0.69). Species-specific molecular RAPD markers were identified for each of the three species; these could be used as auxiliary tools for their correct identification.

A case of advanced medullary thyroid carcinoma successfully treated with sunitinib

CONTEXT

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor arising from "C" cells of the thyroid; it is a RET associated cancer that can be sporadic or familial in origin. Advances in understanding the genetic changes associated with the development of MTC explain the growing interest in the therapeutic potential of tyrosine kinase inhibitors. Sunitinib is an orally administered multikinase inhibitor likely to target multiple pathways in the tumor, stromal, and endothelial compartments. Its role in the treatment of MTC patients has not yet been established.

OBJECTIVE

To present the case of a patient with a sporadic and unresectable MTC who was successfully treated with sunitinib.

PATIENT AND RESULTS

A 55-year-old man with locally advanced MTC, without germinal and/or somatic RET mutations, was started on sunitinib (50 mg/day for 28 days, followed by 14 days of no treatment). At the time of writing, he had received four consecutive cycles. At the end of the first cycle, his serum calcitonin level had dropped by 81%. In the following cycles, a long-lasting minor response was observed. An early and dramatic tumor reduction, particularly of a cervical lymph node conglomerate, was observed and confirmed by the Response Evaluation Criteria in Solid Tumors.

CONCLUSION

Sunitinib may play a role in the management of patients with locally advanced MTC or distant metastatic disease, for which no effective systemic therapy exists. Moreover, the absence of RET mutations does not seem to be an exclusion criterion for sunitinib treatment.

A novel variant in Serpina7 gene in a family with thyroxine-binding globulin deficiency

Thyroxine-binding globulin (TBG) carries approximately 75% of serum T4 and T3. This protein is encoded by serpina7 gene, formerly known as TBG gene, localized on X-chromosome (Xq22.2). A deficiency in TBG is suspected when abnormally low serum total T4 and T3 are encountered in clinically euthyroid subjects in the presence of normal serum TSH. This condition has been associated with different serpina7 gene mutations resulting in amino acid substitutions or truncations in the mature protein. Herein, we report a new serpina7 gene variant in three members of the same family. It results in the replacement of the normal asparagine 233 by isoleucine and, subsequently, in disruption of a glycosylation site. Co-segregation of this new variant with undetectable levels of TBG in the hemizygous man studied and failure to recognize the same variant in 100 alleles at random, made us to consider it as the underlying cause of the TBG deficiency.

Correlation of RET somatic mutations with clinicopathological features in sporadic medullary thyroid carcinomas

Screening of REarranged during Transfection (RET) gene mutations has been carried out in different series of sporadic medullary thyroid carcinomas (MTC). RET-positive tumours seem to be associated to a worse clinical outcome. However, the correlation between the type of RET mutation and the patients' clinicopathological data has not been evaluated yet. We analysed RET exons 5, 8, 10-16 in fifty-one sporadic MTC, and found somatic mutations in thirty-three (64.7%) tumours. Among the RET-positive cases, exon 16 was the most frequently affected (60.6%). Two novel somatic mutations (Cys630Gly, c.1881del18) were identified. MTC patients were divided into three groups: group 1, with mutations in RET exons 15 and 16; group 2, with other RET mutations; group 3, having no RET mutations. Group 1 had higher prevalence (P=0.0051) and number of lymph node metastases (P=0.0017), and presented more often multifocal tumours (P=0.037) and persistent disease at last control (P=0.0242) than group 2. Detectable serum calcitonin levels at last screening (P=0.0119) and stage IV disease (P=0.0145) were more frequent in group 1, than in the other groups. Our results suggest that, among the sporadic MTC, cases with RET mutations in exons 15 and 16 are associated with the worst prognosis. Cases with other RET mutations have the most indolent course, and those with no RET mutations have an intermediate risk.

266 WHOLE GENOME AMPLIFICATION ON BLASTOMERS OF POST-BIOPSY BOVINE EMBRYO

Biopsy of embryos is very useful for choosing the desired sex and for production of cloned and transgenic livestock. However, only a small amount of genomic DNA is available to perform genetic studies. Alternatively, methodologies using whole genome amplification (WGA) have been developed. The aims of this study were to evaluate the effect of WGA on blastomeres removed from 8- to 16-cell bovine embryos and to determine the sex of blastomeres. Oocytes obtained from slaughterhouse ovaries were in vitro matured and fertilized. On the fourth day after fertilization, 8- to 16-cell bovine embryos were biopsied, and one-fourth of an embryo was removed. The blastomeres (n = 56) were submitted to WGA followed by PCR. Prior to the whole genome amplification, male and female bovine DNA samples were serially diluted (30 ng μL–1, 3.0 ng μL–1, 0.3 ng μL–1, 0.03 ng μL–1, 0.003 ng μL–1, 0.0003 ng μL–1) and embryos of various development stages (2, n = 6; 4–7, n = 5; ≥8-cell, n = 5; blastocyst n = 27) were used to standardize PCR protocols and set the amplification limits. To digest the cellular cytoplasm and release the genomic DNA, embryos and blastomeres were submitted a 3 mg mL–1 proteinase K before PCR. Next, blastomeres were submitted to the GenomiPhi DNA Amplification Kit (GE Healthcare) according to manufacturer’s instructions. The product (1 μL) was electrophoresed on a 1% agarose gel stained with 3.0 μg mL–1 ethidium bromide. The reaction mixture was added to the material to be amplified (2 mm MgCl2, 5X PCR buffer, 0.2 mm each dNTPs, 0.05 U μL–1 GoTaq DNA polymerase, 0.25 μm of primer). The products were submitted to electrophoresis on 8% polyacrilamide gel and stained with silver nitrate procedure. The chi-square test was used for statistic evaluation of the results to test the WGA efficiency and to determine the sex rates of bovine embryos and biopsied samples submitted to PCR. It was possible to achieve 98% efficiency in amplifying blastomeres using the WGA kit. Amplified samples showed approximately 400 ng of DNA generated from an estimated initial amount of 12 pg of DNA resulting from two cells per embryo. In whole embryos from different stages, no diffference was detected in the proportion of sexes (P > 0.05). However, a greater number of female samples was noted in biopsied material (76%, 25/33) (P < 0.05). PCR efficiency in blastocysts (93%, 2/27) was statistically greater (P < 0.05) than embryos in early stages of development (83%, 5/6), and biopsied material to 2, 4–7 and ≥8-cell (40%, 2/5; 60%, 3/5; and 59%, 33/56; respectively). These differences could be related to a sex-chromosomal mosaicism or absence of a nucleus in biopsied samples. The WGA creates a DNA stock sample that could be used for various gene profiling and sex determination analyses. Financial support: Fapemig, CNPq.

Comparative genomic hybridization, BRAF, RAS, RET, and oligo-array analysis in aneuploid papillary thyroid carcinomas

Aneuploidy in papillary thyroid carcinomas (PTCs) is considered a marker of worse prognosis. Multiple genetic surveys have been performed in PTCs, however, we are not aware of any such studies in aneuploid PTCs. In order to contribute to a better comprehension of the genetic basis of this neoplasm's more aggressive behaviour in 17 aneuploid PTCs we performed a comparative genomic hybridization (CGH) analysis, studied the BRAF and RAS mutational status, searched for RET/PTC1 and RET/PTC3 rearrangements and determined their expression profile. Array results were validated by TaqMan and immunohistochemistry. CGH revealed multiple non-random chromosomal abnormalities. BRAFV600E and RAS mutations were found in 41.2% and 33% of the carcinomas respectively. None of the studied cases presented RET/PTC1 or RET/PTC3 rearrangement. When comparing array data with the chromosomal, mutational and clinical data we found that: a) loss of control of cellular transcription was of major relevance in this group of neoplasms, HMGA2 being one of the most overexpressed genes; b) gene expression correlated with the mutational status of PTCs, as in BRAF+ cases cMET and FN1 were concomitantly overexpressed; and c) death from disease and distant metastasis was associated to the overexpression of DDR2 and to the down-regulation of genes involved in immune, inflammatory response, signal transduction and cell adhesion processes. In conclusion we have identified in aneuploid PTCs a group of significantly altered molecules that may represent preferential targets for the development of new more efficient therapies in this type of cancer.

Mutation analysis of the RET proto-oncogene and early thyroidectomy: results of a Portuguese cancer centre

BACKGROUND

Evidence that germline mutations in the RET proto-oncogene are the underlying cause of the familial form of medullary thyroid carcinoma (MTC) made it possible to identify gene carriers with a very high degree of accuracy. Aiming to define the mutational profile observed in our patients and to assess gene carriers' compliance with an early surgery, we reviewed results of molecular analysis of RET performed at our institution since 1994.

METHODS

One hundred fifty-eight individuals were screened for germline mutations of the RET proto-oncogene. Seventy-seven patients had apparently sporadic MTC; 8 patients had both MTC and pheochromocytoma or MTC and clinical features of multiple endocrine neoplasia type 2B despite a negative family history; 8 patients were known to belong to affected kindreds; and 65 individuals were at-risk individuals to develop MTC.

RESULTS

A germline mutation in RET was identified in 4% of apparently sporadic MTC patients, in 100% of patients with MTC and pheochromocytoma or MTC and clinical features of multiple endocrine neoplasia type 2B, and in 100% of probands of clinically established kindreds. The most affected codon was 634 (58%) followed by codon 804 (16%). Among at-risk individuals, 49% were identified as gene carriers. Seven individuals were submitted to prophylactic thyroidectomy (mean age, 17.7 +/- 12.5 years; range: 3-42 years), and all but 1 had MTC.

CONCLUSIONS

RET mutational spectrum observed in the present population disclosed a higher frequency of codon 804 mutations than expected. Compliance with an early prophylactic surgery seemed to be influenced not only by medical advice and cultural factors but also by the aggressiveness of disease in gene carriers' families.

Searching for RET/PTC rearrangements and BRAF V599E mutation in thyroid aspirates might contribute to establish a preoperative diagnosis of papillary thyroid carcinoma

OBJECTIVE

Searching for multiple molecular markers in thyroid aspirates appears to be a promising approach for establishing a preoperative diagnosis of papillary thyroid carcinoma (PTC).

METHODS

Based on this hypothesis, a total of 63 samples from 55 patients, were collected at random. RNA was extracted from the residue cells inside the needle used for fine needle aspiration cytology (FNAC) and thereafter molecular analysis was carried out both for RETrearrangements (type 1, 2, 3) and BRAF codon 599 mutation molecule. Results were compared with the cytological and histopathological diagnoses in 24 patients submitted to surgery.

RESULTS

58% PTCs presented a genetic alteration either RET/PTC rearrangement, BRAF V599E mutation or both: three cases of PTCs (25%) presented a RET/PTC rearrangement; three cases of PTCs (25%) presented a BRAF V599E mutation and in one case (8%) both alterations were identified.

CONCLUSIONS

The present results suggest that searching for multiple molecular markers in thyroid aspirates may enhance the accuracy of FNAC and refine preoperative diagnosis of PTC.

RET polymorphisms and sporadic medullary thyroid carcinoma in a Portuguese population

The genetic basis of the sporadic form of medullary thyroid carcinoma, derived from "C" cells, is still poorly understood. Somatic mutations of RET proto-oncogene have been reported at a variable frequency ranging from 23% to 69%. The hypothesis that low penetrance factors, such as polymorphisms, might contribute to the phenotype of this neoplasm has been addressed in a few studies conducting to conflicting results. Herein, we studied 100 individuals (50 patients and 50 controls) aiming to compare the frequencies of G691S, L769L, S836S, and S904S RET polymorphisms observed in patients with respect to controls. Furthermore, meta-analysis of published studies including the present results was conducted. To test the contributory role of the above polymorphisms for the development of "C"-cell hyperplasia, we studied a group of 10 individuals selected for having a positive pentagastrin test despite the absence of a RET germline mutation. An over-representation of the G691S polymorphism, particularly in females, was observed in patients with respect to controls, although not reaching the level of significance. Allelic frequencies of the other three polymorphisms were not different in patients and controls. Results obtained in the admittedly small group of individuals with a positive pentagastrin test are unlikely to support a major influence of any polymorphism in the development of "C"-cell hyperplasia. The meta-analysis provided evidence for a significant association of the S691 allele with MTC (odds ratio 1.54, 95% confidence interval 1.12-2.12, p=0.008) and found no significant associations for the other polymorphisms.

Immunostaining and RT-PCR: different approaches to search for RET rearrangements in patients with papillary thyroid carcinoma

Different techniques of molecular biology have been used to screen for RET rearrangements. More recently, immunohistochemistry has been used, assuming that RET is not expressed in normal thyroid follicular cells. The present study was designed to define the prevalence of RET expression in patients with papillary thyroid carcinoma, by immunohistochemistry and by RT-PCR; to search specifically for RET/PTC-1; -2; -3 rearrangements using RT-PCR, and to compare results obtained by immunohistochemistry with those obtained by RT-PCR. Immunohistochemistry was performed using a polyclonal antibody against tyrosine kinase domain of Ret protein. Screening for RET/PTC1-3 was performed using RT-PCR and specific primers for each rearrangement; complementarily, a subset of cases were tested using RET exon 10/11 primers designed to detect the expression of the wild-type RET. Positive staining was observed in 30 of 39 (77%) tumours. RET/PTC1-3 rearrangements were detected in 8 of 32 (25%) cases. Ten of 15 (67%) cases expressed the wild-type RET. Two tumours characterised by positive immunostaining, absence of RET 5' expression and absence of RET/PTC1-3 expression were considered as expressing a RET rearrangement different from RET/PTC-1, -2, or -3. In 3 of 10 tumours, expression of the wild-type RET coexisted with the expression of a RET rearrangement. Positive staining does not necessarily mean the presence of a rearrangement; it may correspond to the expression of the wild-type RET, RET rearrangement or both. On the contrary, positive staining without evidence for the expression of the extracellular domain of RET is highly suggestive of a RET rearrangement independently of the type. Refinement of diagnosis depends on RT-PCR with specific primers.

MEN 2A families: from hot spots to hot regions

The aim of this study was to look for common ancestors among MEN 2A Portuguese families presenting with the same germ-line mutation of the RET proto-oncogene. To address this question from a genetic point of view, we performed haplotype analysis in six out of nine, apparently separate, MEN 2A families using four polymorphic markers. Three families carrying the C634R mutation and presenting the same phenotype shared the same haplotype surrounding the MEN 2A mutation. Moreover, these families were originally from the same geographic region although settled at different places along the country. Altogether, data suggested a common ancestral MEN 2A chromosome for three families. Since MEN 2A is a rare inherited cancer syndrome, identification of common ancestors may draw attention for specific geographic regions from where other affected families may arise at a higher chance and, therefore, termed 'hot regions'.

The minisequencing method: a simple strategy for genetic screening of MEN 2 families

BACKGROUND

Multiple endocrine neoplasia type 2 is an autosomal dominant disorder. MEN 2A is characterized by medullary thyroid carcinoma, pheochromocytoma and hyperparathyroidism; MEN 2B by medullary thyroid carcinoma, pheochromocytoma and characteristic stigmata. Activating germline mutations of the RET proto oncogene are responsible for this hereditary syndrome. Codon 634 mutations are the most common mutations occurring in MEN 2A families whereas a specific mutation at codon 918 is observed in the great majority of MEN 2B families. Analysis of these codons will provide a final diagnosis in the great majority of affected families making unnecessary further studies. To specifically study the codons 634 and 918 we used a minisequencing method as an alternative method to complete sequencing.

RESULTS

Using this mutation detection method we were able to reproduce in all cases, representative of 7 families, the information previously obtained by direct sequencing of PCR products. Depending on the number of primers used in the minisequencing reaction, we were able to interrogate either only one nucleotide of the target codon or the three nucleotides simultaneously.

CONCLUSIONS

This technique appears as a simple, rapid and efficient method for genetic screening of MEN 2 families. It can be utilized to seek for unknown mutations at specific codons or to screen for previously identified mutations and is therefore of interest to study index cases or individuals at risk. Results suggest that complete sequencing is unnecessary.

Mutational analysis of Portuguese families with multiple endocrine neoplasia type 1 reveals large germline deletions

OBJECTIVE

To determine the spectrum of MEN1 mutations in Portuguese kindreds, and identify mutation-carriers.

PATIENTS, DESIGN AND RESULTS

Six unrelated MEN1 families were studied for MEN1 gene mutations by single-strand conformational polymorphism (SSCP) and DNA sequence analysis of the coding region and exon-intron boundaries of the MEN1 gene. These methods identified 4 different heterozygous mutations in four families: two mutations are novel (mt 1539 delG and mt 655 ims 11 bp) and two have been previously observed (mt 735 del 46p and mt 1656 del C) all resulting in a premature stop codon. In the remaining two families, in whom no mutations or abnormal MEN1 transcripts were detected, segregation studies of the 5' intragenic marker D11S4946 and codon 418 polymorphism in exon 9 revealed two large germline deletions of the MEN1 gene. Southern blot and tumour loss of heterozygosity analysis confirmed and refined the limits of these deletions, which spanned the MEN1 gene at least from: exon 7 to the 3' untranslated region, in one family, and the 5' polymorphic site D11S4946 to exon 9 (obliterating the initiation codon), in the other family. Twenty-six mutant-gene carriers were identified, 6 of which were asymptomatic.

CONCLUSIONS

These results emphasize the importance of the detection of MEN1 germline deletions in patients who do not have mutations of the coding region. Important clues indicating the presence of such deletions may be obtained by segregation studies using the intragenic polymorphisms D11S4946 and at codon 418. The detection of these mutations will help in the genetic counselling of clinical management of the MEN1 families in Portugal.

Two novel variants in the thyroxine-binding globulin (TBG) gene behind the diagnosis of TBG deficiency

OBJECTIVE

Search for germline mutations in the thyroxine-binding globulin (TBG) gene of two unrelated Portuguese females of Caucasian origin in whom the diagnosis of TBG deficiency was suspected because of suppressed TSH despite marginally low total thyroxine and tri-iodothyronine.

DESIGN AND METHODS

Screening for germline mutations was conducted by non-radioactive PCR-SSCP analysis. The variants documented by this approach were characterized by sequencing. Moreover, in order to define whether they were mutations or polymorphisms we looked for the same variants analysing 100 alleles at random. To achieve this goal we used, alternatively, restriction analysis and the minisequencing method with an automated capillary electrophoresis system and fluorescent-labelled dideoxynucleotides.

RESULTS AND CONCLUSIONS

Two novel variants, one in each patient, were identified. One, involved codon 23 (TCA-->TAA) and the other, codon 223 (CAA-->TAA). Analysis of 50 DNA samples, randomly chosen, revealed that all were homozygous for the wild variant at codon 23. One of them was heterozygous for the variant CAA-->TAA at codon 223. This sample was found to correspond to a Caucasian female in whom serum TBG proved to be not detected. Since both variants identified result in stop codons likely to induce truncated TBG proteins, they are probably responsible for the TBG phenotype observed in the individuals studied.

Future trends in worldwide river nitrogen transport and related nitrous oxide emissions: a scenario analysis

We analyze possible future trends in dissolved inorganic nitrogen (DIN) export by world rivers and associated emissions of nitrous oxide (N2O). Our scenarios either assume that current trends continue or that nitrogen (N) inputs to aquatic systems are reduced as a result of changes in agriculture practices and fuel combustion technologies. The results indicate that moderate changes in the human diet in North America and Europe, reducing worldwide fertilizer use by only 16%, relative to Business-as-Usual (BAU) levels, may reduce DIN export rates to the North Atlantic and European Seas by about one third and associated N2O emissions by 36 to 77%. We furthermore calculate that relatively large reductions in NOy deposition rates in Europe (of about 80%) may reduce DIN export by rivers by a moderate 8% or less, relative to BAU levels. The potential effect of reduced NOy deposition on riverine DIN export is moderate, because most N in European rivers stems from agriculture, and not from fuel combustion. Nevertheless, the calculated 9% reduction (relative to BAU) in DIN inputs to the North Sea as a potential side effect of air pollution control may help achieve the international policy targets for reduced N inputs to the North Sea.

Neurocysticercosis in a preschool-age child: case report

Neurocysticercosis is a frequent cause of epilepsy and other neurologic abnormalities in all age groups, however by virtue of its prolonged incubation period as well as young children's nutritional habits, it is rarely seen in preschool-age children. The objective of this study is to report the case of a 2 year-old child who presented with new-onset seizures. Her diagnostic features, including neuroradiologic findings, are described and compared with the literature. No matter how young he or she may be, every child who presents with new-onset seizures or other unexplained neurologic features and whose CT or MRI shows cystic lesions or contrast-enhancing rounded lesions should raise a suspicion of neurocysticercosis.