An identical, complex TP53 mutation arising independently in two unrelated families with diverse cancer profiles: the complexity of interpreting cancer risk in carriers.

Most inherited TP53 mutations have been identified in individuals with a family cancer predisposition syndrome, in which the activity of p53 mutants is severely reduced. However, germline p53 mutants in children with 'sporadic' adrenocortical or choroid plexus tumors exhibit a wide range of functional activity. Here, we demonstrate the occurrence of a complex germline TP53 mutation in two unrelated families with different cancer phenotypes, neither fulfilling the classic criteria for Li-Fraumeni syndrome. The TP53 mutation consists of a duplication of 7 bp in exon 4, resulting in a frame shift and premature stop signal. Haplotype analysis indicated that the mutation arose independently in the two families. Analysis of the DNA secondary structure predicts the TP53 mutation occurred within a hairpin loop. Additional germline complex mutations occurring within the same region of exon 4 have been identified in the IARC database. Our findings suggest that certain TP53 regions are prone to intrinsic genetic alterations, possibly through defects in DNA replication or repair. Further, carriers of the same TP53 mutation can have diverse cancer profiles, illustrating the complexity of genetic counseling and risk prediction.

Mechanism of formation and construction of self-assembled myoglobin/hyaluronic acid multilayer films: an electrochemical QCM, impedance, and AFM study.

Self-assembled multilayer films of hyaluronic acid (HA) and the protein myoglobin (Mb) were built up layer by layer on Au covered quartz crystal microbalance (AuQCM) electrode substrates. Film formation and growth were monitored by an electrochemical quartz crystal microbalance (EQCM), and the step-by-step construction was investigated through quantification of the mass variation corresponding to adsorption of each monolayer together with cyclic voltammetry. A decrease of friction at the liquid/electrode interface was observed, indicating that the electrode surface becomes less rough after deposition of several monolayers. The properties of the {HA/Mb}(n) films were evaluated by electrochemical impedance spectroscopy (EIS). Modeling of the impedance spectra shows smoothing of the modified electrode surface with reorganization of the film structure after few monolayers, and the contribution of each layer to the electron transfer process was analyzed. The smoothing of the surfaces and the structural differences between successive bilayers was confirmed by morphological observations by using atomic force microscopy.

Molecular analysis of CYP21A2 can optimize the follow-up of positive results in newborn screening for congenital adrenal hyperplasia.

Neonatal screening for congenital adrenal hyperplasia (CAH) is useful in diagnosing salt wasting form (SW). However, there are difficulties in interpreting positive results in asymptomatic newborns. The main objective is to analyze genotyping as a confirmatory test in children with neonatal positive results. Patients comprised 23 CAH children and 19 asymptomatic infants with persistently elevated 17-hydroxyprogesterone (17OHP) levels. CYP21A2 gene was sequenced and genotypes were grouped according to the enzymatic activity of the less severe allele: A1 null, A2 < 2%, B 3-7%, C > 20%. Twenty-one children with neonatal symptoms and/or 17OHP levels > 80 ng/ml carried A genotypes, except two virilized girls (17OHP < 50 ng/ml) without CAH genotypes. Patients carrying SW genotypes (A1, A2) and low serum sodium levels presented with neonatal 17OHP > 200 ng/ml. Three asymptomatic boys carried simple virilizing genotypes (A2 and B): in two, the symptoms began at 18 months; another two asymptomatic boys had nonclassical genotypes (C). The remaining 14 patients did not present CAH genotypes, and their 17OHP levels were normalized by 14 months of age. Molecular analysis is useful as a confirmatory test of CAH, mainly in boys. It can predict clinical course, identify false-positives and help distinguish between clinical forms of CAH.

ABO genotyping in leukemia patients reveals new ABO variant alleles.

The ABO blood group is the most important blood group system in transfusion medicine and organ transplantation. To date, more than 160 ABO alleles have been identified by molecular investigation. Almost all ABO genotyping studies have been performed in blood donors and families and for investigation of ABO subgroups detected serologically. The aim of the present study was to perform ABO genotyping in patients with leukemia. Blood samples were collected from 108 Brazilian patients with chronic myeloid leukemia (N = 69), chronic lymphoid leukemia (N = 13), acute myeloid leukemia (N = 15), and acute lymphoid leukemia (N = 11). ABO genotyping was carried out using allele specific primer polymerase chain reaction followed by DNA sequencing. ABO*O01 was the most common allele found, followed by ABO*O22 and by ABO*A103. We identified 22 new ABO*variants in the coding region of the ABO gene in 25 individuals with leukemia (23.2%). The majority of ABO variants was detected in O alleles (15/60.0%). In 5 of 51 samples typed as blood group O (9.8%), we found non-deletional ABO*O alleles. Elucidation of the diversity of this gene in leukemia and in other diseases is important for the determination of the effect of changes in an amino acid residue on the specificity and activity of ABO glycosyltransferases and their function. In conclusion, this is the first report of a large number of patients with leukemia genotyped for ABO. The findings of this study indicate that there is a high level of recombinant activity in the ABO gene in leukemia patients, revealing new ABO variants.

ABO genotyping in leukemia patients reveals new ABO variant alleles

The ABO blood group is the most important blood group system in transfusion medicine and organ transplantation. To date, more than 160 ABO alleles have been identified by molecular investigation. Almost all ABO genotyping studies have been performed in blood donors and families and for investigation of ABO subgroups detected serologically. The aim of the present study was to perform ABO genotyping in patients with leukemia. Blood samples were collected from 108 Brazilian patients with chronic myeloid leukemia (N = 69), chronic lymphoid leukemia (N = 13), acute myeloid leukemia (N = 15), and acute lymphoid leukemia (N = 11). ABO genotyping was carried out using allele specific primer polymerase chain reaction followed by DNA sequencing. ABO*O01 was the most common allele found, followed by ABO*O22 and by ABO*A103. We identified 22 new ABO* variants in the coding region of the ABO gene in 25 individuals with leukemia (23.2%). The majority of ABO variants was detected in O alleles (15/60.0%). In 5 of 51 samples typed as blood group O (9.8%), we found non-deletional ABO*O alleles. Elucidation of the diversity of this gene in leukemia and in other diseases is important for the determination of the effect of changes in an amino acid residue on the specificity and activity of ABO glycosyltransferases and their function. In conclusion, this is the first report of a large number of patients with leukemia genotyped for ABO. The findings of this study indicate that there is a high level of recombinant activity in the ABO gene in leukemia patients, revealing new ABO variants.

Dissociation between tumor shrinkage and hormonal response during somatostatin analog treatment in an acromegalic patient: preferential expression of somatostatin receptor subtype 3.

INTRODUCTION: About a third of acromegalic patients is resistant to available SS analogs (SA), octreotide (OCT) and lanreotide (LAN). Such resistance is related to reduction of SS receptor (SSTR) density or to a different expression of SSTR subtypes. There are 5 known SSTR subtypes. SSTR2 and SSTR5 are usually expressed in GH-secreting pituitary tumors, and both SA bind preferentially to SSTR2 and, to a lesser extent, to SSTR5. We herein describe an acromegalic patient who presented impressive tumor shrinkage without hormonal normalization during primary therapy with SA. MATERIAL AND METHODS: This 23-yr-old male acromegalic patient was treated with slow-release LAN (LAN-SR), 30 mg every 10 days for six months, followed by OCT-LAR, 30 mg every 28 days for an additional six months with a 75% tumor volume reduction but without GH and IGF-I normalization. Subsequently, he underwent pituitary surgery and expression of SSTR in the removed tumor was performed by real time RT-PCR by the 2-deltaCt method, using GAPDH as internal control. All PCR products were confirmed by automated sequencing. RESULTS: SSTR expression revealed an unusual profile, with almost exclusively expression of SSTR3. CONCLUSIONS: These unusual clinical and receptor subtypes profile suggest an important role of SSTR3 on tumor shrinkage. The low affinity of LAN and OCT for this SSTR subtype could be compensated by its high expression in this GH-secreting pituitary macroadenoma.

Pericardial effusion and cardiac tamponade as complications of neonatal long lines: are they really a problem?

AIM: To estimate the frequency of pericardial effusion/cardiac tamponade associated with the use of neonatal percutaneous long lines (PLLs) over the past five years. METHOD: A retrospective nationwide postal survey, of all neonatal and special care units in the United Kingdom. RESULTS: Eighty two cases of pericardial effusion/cardiac tamponade were reported from the five year period, during which we estimate that 46 000 PLLs were inserted. The calculated frequency of pericardial effusion/cardiac tamponade occurring with PLLs was 1.8/1000 lines. There were 30 deaths, giving a fatality rate after pericardial effusion of 0.7/1000 lines. CONCLUSIONS: Pericardial effusion/cardiac tamponade is a serious but infrequent complication of PLL use.

Evaluation of CT in identifying colorectal carcinoma in the frail and disabled patient.

Frail and physically or mentally disabled patients frequently have difficulty in tolerating formal colonic investigations. The aims of this study were to evaluate the accuracy of minimal-preparation CT in identifying colorectal carcinoma in this population and to determine the clinical indications and radiological signs with the highest yield for tumour. The CT technique involved helical acquisition (10-mm collimation, 1.5 pitch) following 2 days of preparation with oral contrast medium only. The outcome of 4 years of experience was retrospectively reviewed. The gold standards were pathological and cancer registration records, together with colonoscopy and barium enema when undertaken, with a minimum of 15 months follow-up. One thousand seventy-seven CT studies in 1031 patients (median age 80 years) were evaluated. CT correctly identified 83 of the 98 colorectal carcinomas in this group but missed 15 cases; sensitivity and specificity (with 95% confidence interval) 85% (78-92%) and 91% (90-93%), respectively. Multivariate analysis identified: (a) a palpable abdominal mass and anaemia to be the strongest clinical indications, particularly in combination (p<0.0025); and (b) lesion width and blurring of the serosal margin of lesions to be associated with tumours (p<0.0001). Computed tomography has a valuable role in the investigation of frail and otherwise disabled patients with symptoms suspicious for a colonic neoplasm. Although interpretation can be difficult, the technique is able to exclude malignancy with good accuracy.

Caecal carcinomas in the elderly: useful signs in minimal preparation CT.

OBJECTIVE: Frail, elderly and immobile patients frequently have difficulty in tolerating formal colonic investigations. Caecal tumours may account for up to 35% of colonic tumours. Barium enema and colonoscopy have limitations in assessing this region. The aims of this study were to evaluate the accuracy of a minimal preparation CT technique (merely with prolonged oral contrast medium) in identifying caecal carcinomas and to determine helpful radiological signs. MATERIALS AND METHODS: The CT technique involved helical acquisition following 2 days of preparation with oral contrast medium. The outcome of 4 years' experience (1995-1998) was reviewed. The gold-standards were pathological and cancer registration records, together with colonoscopy and barium enema where available, with a minimum of 15 months' follow-up. RESULTS: CT correctly identified 27 of 30 caecal carcinomas, and missed three, in a total of 1077 CT studies in 1031 patients (median age 80 years). There were also 21 false-positive cases in which CT incorrectly raised the possibility of a caecal tumour. The sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were 90%, 98%, 99% and 56%, respectively. Serosal margin blurring, tumour length, presence of abnormal peri-colic fat and terminal ileal wall thickening were identified as useful radiological signs. CONCLUSIONS: Minimal preparation CT is able to identify caecal carcinomas with fair accuracy. Such evaluation may become important given the increasing population age and evidence of a 'proximal shift' in the site of colonic tumours in the elderly.

An inherited mutation outside the highly conserved DNA-binding domain of the p53 tumor suppressor protein in children and adults with sporadic adrenocortical tumors.

Mutations of the p53 tumor suppressor gene are the single most common genetic alterations in human cancers. Recently, a distinct nucleotide substitution was identified in exon 10 of the p53 gene, leading to an Arg337His mutation in 97% of children with adrenocortical tumors from Southern Brazil. In the present study, we investigated the presence of this mutation in a larger series of 55 patients (37 adults and 18 children) with benign and malignant sporadic adrenocortical tumors. None of the patients had family cancer histories that conformed to the criteria for Li-Fraumeni syndrome. Twenty-one asymptomatic close relatives of patients with p53 mutations and 60 normal unrelated individuals were also studied. The missense Arg337His mutation was identified in 19 patients (14 children and 5 adults), and 8 of 11 cases studied had LOH. Among the 19 patients with the Arg337His mutation, only one boy and three adults showed fatal evolution or recurrent metastases. This mutation was also identified in heterozygous state in asymptomatic first-degree relatives of the patients, indicating that Arg337His mutation was inherited in most cases. In contrast, this mutation was not found in 120 alleles of normal unrelated controls. In conclusion, the germ line Arg337His mutation of p53 protein is present at a high frequency (77.7%) in children with benign or malignant sporadic adrenocortical tumors, but it is not restricted to the pediatric group, since 13.5% of adults with adrenocortical tumors also had this mutation. The presence of this mutation was related to unfavorable prognosis in most of the adults, but not in the children with adrenocortical tumors.

Geraldo de Sá 1922-1987 / Geraldo de Sá 1922-1987

O autor dilineia o perfil biográfico de um dos mais notáveis otorrinolaringologistas brasileiros da segunda metade do século atual