HLA-B*38:55Q: a new alternatively expressed allele identified in a three-generation Italian family.

The new allelic variant HLA-B*38:55Q differs from the closest related B*38:01:01 by one nucleotide substitution at position 373 in exon 3 (TGC>CGC). This results in a difference of one amino acid at residue 101 of the HLA-B heavy chain, from a neutral-polar Cys to a basic-polar Arg, thus impairing disulphide bridge formation in the alpha-2 domain. This alteration of the secondary structure probably affects the maturation of the heavy chain and the level of surface expression, making the HLA-B*38:55Q undetectable by standard serological typing.

RNA complementary to the 5' UTR of mRNA triggers effective silencing in Saccharomyces cerevisiae.

Conditional silencing of target genes in Saccharomyces cerevisiae by antisense RNAs expressed in vivo has been challenged. The MFalpha1::lacZ fusion present in S. cerevisiae SF51-3 was chosen as a model target, and fragments of this gene were cloned in reverse orientation into the expression vector pYES2, bearing the GAL1 promoter. Among the different antisense constructs tested, only the one complementary to the 5' UTR of target mRNA featured effective silencing. Nevertheless, the expression in vivo of this antisense RNA could not be properly tuned by the absence or presence of galactose in the culture medium. Accordingly, conditional silencing could not be attained by this antisense hosted into pYES2. On the contrary, cloning the same antisense construct into the expression vector pSAL4 yielded a fully conditional silencing linked to the control of antisense expression by the absence or presence of Cu(2+) into the culture medium.

Determination of the in vivo effects of prednisone on Bcl-2 family protein expression in childhood acute lymphoblastic leukemia.

Glucocorticoid resistance is often associated with treatment failure in children with acute lymphoblastic leukaemia (ALL) but the underlying molecular mechanisms are still unclear. In 30 consecutive children with ALL treated with prednisone we determined changes in the expression of Bcl-2, Bax and Bcl-xl proteins in leukemic lymphoblasts and related these to clinical features and rate of prednisone-induced apoptosis. The apoptotic index increased after prednisone therapy in 24 of the 30 patients. At diagnosis, we detected expression of Bcl-2 and Bcl-xl protein in 28 samples, while Bax expression protein was detected in 21 of the 30 patients. Prednisone treatment induced a decrease in Bcl-2 and Bcl-xl levels in 17 and 16 of the 28 patients, respectively, while Bax protein increased in 14 of the 21 patients. Twenty of the 30 patients studied were considered to be good prednisone responders, whereas 10 were poor responders. We observed a statistically significant decrease only for Bcl-xl protein expression in T phenotype ALL, in the poor responder group and in patients with >20000/mm(3) white cell count (WBC) at diagnosis. These data suggest a role of Bcl-xl in the mechanisms of protection of leukemic cells from apoptosis induced by glucocorticoids (GCs).

Foliar application of selenite and selenate to potato (Solanum tuberosum): effect of a ligand agent on selenium content of tubers.

The effect of a foliar spray of selenium on potatoes was investigated for 2 years. Amounts of 0, 50, and 150 g of Se ha(-)(1) were applied both as sodium selenate and as sodium selenite in water, either pure or with the addition of 0.15% of soluble leonardite as a source of humic acids (pH 7). Tuber selenium concentration increased with the application levels, both with sodium selenate and with sodium selenite, when only aqueous solutions were used. When humic acids were added, the tuber selenium level rose more markedly after the application of sodium selenate as compared to the case of the aqueous solutions; however, in the case of sodium selenite, the level showed a large increase only after the application of 50 g of Se ha(-)(1). Kinetics showed that humic acids raised the selenate availability, but no differences were found in the distribution of selenium in the tuber fractions. Foliar application of selenium with humic acids was proven to be a good way to increase the selenium content of potatoes, but the assimilation process of selenium was simpler with selenate than with selenite.

Hematopoietic stem cell transplantation in childhood: report from the bone marrow transplantation group of the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP).

BACKGROUND AND OBJECTIVE: Transplantation of hematopoietic stem cells from different sources is being increasingly used to treat a variety of diseases in children. Transplant procedures and indications have changed considerably during recent years. Monitoring of information about these changes is useful for interpretation of nationwide collected data. DESIGN AND METHODS: Since 1985, Centers belonging to the AIEOP (Associazione Italiana Ematologia Oncologia Pediatrica), performing hematopoietic stem cell transplants (HSCT) in children, and members of the AIEOP-Bone Marrow Transplant (BMT) Group annually report data on their transplant activity to the AIEOP-BMT Registry employing specially prepared patient-oriented forms. RESULTS: From January 1985 to December 1998, a total of 2,474 bone marrow (BM), peripheral blood (PB) or umbilical cord blood (CB) transplants were reported: 1,296 (52%) were allogeneic (Allo) and 1,178 (48%) autologous (Auto) transplants. These transplants were performed in 19 Italian Centers on 2,249 patients aged less than 17 years. Among Allo-transplants, 1,198 (92%) were performed using BM progenitor cells, whereas 49 (4%) CB, 42 (3%) were PB, 4 BM plus PB, and 3 BM plus CB allografts; they were performed using HLA-identical sibling donors in 867 cases (67%) and alternative donors (i.e. partially-matched relatives or unrelated donors) in the remaining 429 (33%) cases. Allogeneic transplants were performed on 786 (67%) patients with malignancy and on 395 (33%) patients with non-malignant disorders. In the last 6 years, the number of Allo-transplants per year exceeded that of Auto-transplants. Of the Auto-transplants, 775 (66%) were performed using BM, and 403 (34%) using PB alone or combined with BM hematopoietic stem cells. Indications for Auto-BMT were myelo-lymphoproliferative disorders in 524 (49%) cases, solid tumor in 533 (50%) cases and non-malignant disease in 11 (1%) cases. In the last 5 years, the use of PB for autografts has increased from 7% to 70%. INTERPRETATION AND CONCLUSIONS: These data reflect the development and present status of HSCT in Italy and provide a basis for patient counseling and health care planning.

Lipophilic thiamine treatment in long-standing insulin-dependent diabetes mellitus.

Thiamine plays an important role in the regulation of glucose metabolism and pancreatic beta-cell functioning. A role for this vitamin in cellular glucose transport has been indicated in the literature. The aim of this study was to determine whether a lipophilic form of thiamine (benzoyloxymethyl-thiamine, BOM) was able to improve metabolic control in patients with long-standing insulin-dependent diabetes mellitus (type 1). A total of 10 children with type 1 diabetes of long duration (age 11.4 +/- 1.2 years, duration of the disease 4.5 +/- 0.7 years, means +/- SEM) were studied before and after treatment with BOM in a randomized double-blind and placebo-controlled study. Five patients were assigned to the BOM-treated group and five to the placebo-group. In all patients basal and glucagon-stimulated C-peptide secretion was undetectable. Thiamine status was assayed by measuring the plasma content of thiamine and its monophosphate form at entry and after 3 months of treatment. The blood HbA(1C) levels and the daily dose of insulin per kg body weight were assessed in both groups before treatment, after 1 month and 3 months of treatment, then 3 months following its suspension. The plasma content of thiamine + thiamine monophosphate in type 1 diabetic patients (35.3 +/- 3.6 pmol/mL) was significantly lower when compared with that measured in six age-matched normal subjects (53.2 +/- 2.3 pmol/mL, P < 0.05).

Standardized echography, pattern electroretinography and visual-evoked potential and automated perimetry in the early diagnosis of Graves' neuropathy.

Twenty-four patients (47 eyes) affected by Graves' disease were enrolled to evaluate the role of standardized echography, pattern electroretinogram (P-ERG), visual evoked potentials (P-VEPs) and automated perimetry in the early diagnosis of the compressive optic neuropathy (CON). The P-ERG amplitude reduction was the most sensitive parameter to demonstrate an early impairment of the optic nerve (ON) function. We found a significant negative correlation between the ON diameter and the P-ERG amplitude. VEPs responses were also altered, but their ability in detecting an early ON damage was less sensitive and specific than P-ERG. The visual field damage was often aspecific and delayed with respect to electrophysiological alterations.

Long-term follow-up of diabetes in two patients with thiamine-responsive megaloblastic anemia syndrome.

OBJECTIVE: To describe a 15-year follow-up of diabetes and to present data regarding pancreatic beta-cell function in two adolescents affected by the thiamine-responsive megaloblastic anemia (TRMA) syndrome. CASE REPORTS: The first patient (PMR) is a 17.5-year-old Italian girl who presented megaloblastic anemia at 7.5 months of age. At age 2.5 years, because of the presence of diabetes and sensorineural deafness, she was diagnosed with TRMA syndrome and started treatment with thiamine-HCl, followed very early by benzoyloxymethyl-thiamine (BOM-T). The second patient (PF) is a 16.8-year-old Italian boy born to consanguineous parents. Sensorineural deafness was diagnosed at age 1.5 years, while diabetes with ketoacidosis and megaloblastic anemia were diagnosed at age 3 years. Treatment with thiamine HCl was started immediately after diagnosis and changed to BOM-T 2 months later. Subsequent to the initiation of the vitamin, the two patients did not require insulin for approximately 7 and 10 years, respectively. Puberty was determinant in deteriorating the metabolic control in these patients, leading to treatment with an oral hypoglycemic agent and finally to a reinstitution of insulin therapy. CONCLUSIONS: The hormonal assessment in our patients (normal insulin response to oral glucose in childhood, preserved C-peptide secretion in case 2) and the good response to an oral hypoglycemic agent would indicate that the pancreatic disease may initiate as type 2 diabetes and may progress after several years to an insulin-requiring diabetes, as indicated by the exhaustion of the insulin secretory capacity.

Interstitial 9q deletion is associated with CD7+ acute leukemia of myeloid and T lymphoid lineage.

We report the clinical, hematological and immunophenotypic characteristics from four cases of acute leukemia with interstitial deletion of chromosome 9, ie del(9)(q12-q22), as a single chromosomal abnormality. Three patients had acute myeloblastic leukemia (AML) and one T origin acute lymphoblastic leukemia (ALL). According to FAB classification, blasts were classified as M1 (two patients), M2 (one patient), and L2 (one patient). In two out of three AML cases a myelodysplastic syndrome, one AREB-t and one AREB diagnosed 6 and 11 months before respectively, preceded the onset of AML. Morphological examination showed dysgranulopoiesis, dyserythropoiesis and cytoplasmic vacuoles in two AML patients, while a strong positivity to myeloperoxidases was observed in all AML cases. As concerns immunophenotypic findings, blast cells from two of three AML patients expressed CD7 and CD34, while those from the T-ALL case displayed CD33 and CD34 along with CD7. These observations suggest that del (9q) is associated with CD7+ acute leukemia of myeloid or lymphoid lineage.

Treatment of EBV-induced lymphoproliferative disorder with epipodophyllotoxin VP16-213.

A case of haemophagocytic lymphohistiocytosis consistent with X-linked lymphoproliferative disorder is described. Remission was observed after administration of VP-213, a cytotoxic drug generally used to treat histiocytosis. The child is currently in good clinical health.

Immunologic and intestinal permeability tests as predictors of relapse during gluten challenge in childhood coeliac disease.

Fifteen children with an initial diagnosis of coeliac disease underwent gluten challenge either because they had never had a jejunal biopsy or because they had had one during the first 2 years of life. The challenge was preceded by a biopsy; clinical symptoms, the cellobiose/mannitol permeability test, and gliadin and endomysial antibody measurement were used to determine the timing of the confirmatory biopsy: it was performed if one test result was repeatedly abnormal or two results were concomitantly abnormal. Gliadin antibodies increased early (already 7 days after the reintroduction of gluten to the diet), but in many cases they returned to normal values thereafter. Increased intestinal permeability to sugars and even more positivity of endomysial antibody were good predictors of histologic relapse. The sequential use of laboratory tests during gluten challenge may significantly shorten its duration.

Further studies on erythrocyte thiamin transport and phosphorylation in seven patients with thiamin-responsive megaloblastic anaemia.

Erythrocyte thiamin metabolism and transport were investigated in 7 patients from Brazil, Israel and Italy suffering from thiamin-responsive megaloblastic anaemia (TRMA) associated with diabetes mellitus and sensorineural deafness. All patients discontinued thiamin therapy for 4-7 days before the investigation. TRMA patients showed invariably reduced total thiamin levels in erythrocytes (percentage reduction compared with healthy controls, -46.8 +/- 3%; mean +/- SEM). The proportions of individual thiamin compounds, expressed as a percentage of total thiamin content, were within the normal range, whereas their absolute amounts were significantly decreased in the following order: thiamin monophosphate > thiamin pyrophosphate > thiamin. Thiamin pyrophosphokinase activity was also reduced as compared with controls (mean reduction +/- SEM, -25.9 +/- 1%). The saturable, specific component of thiamin uptake, which normally prevails at physiological concentrations of thiamin (< 2 mumol/L), was absent in erythrocytes obtained from TRMA patients, while the non-saturable (diffusive) component of uptake was normally present. These results confirm observations made previously in two patients and demonstrate that TRMA is consistently associated with a state of thiamin deficiency, which is presumably secondary to reduced thiamin cellular transport and absorption (caused by lack of a membrane-specific carrier), and to impaired intracellular pyrophosphorylation.

Hb-M "Hyde Park": a de novo mutation, identified by mass spectrometry and DNA analysis.

BACKGROUND: Structural hemoglobinopathies usually are inherited as autosomic dominant traits; de novo mutations are uncommon. Analytical and preparative procedures for the characterization of an abnormal hemoglobin are complex and time-consuming. Mass spectrometer analysis allows a rapid identification of the amino acid substitution. METHODS AND RESULTS: A cyanotic 7-year-old girl was found to have 16% methemoglobin. Laboratory data showed the presence of an abnormal hemoglobin, which was isolated by collecting the abnormal peak from DEAE and globin chains from CM52. The amino acid substitution was rapidly identified by FAB mass spectroscopic analysis, leading to the recognition of HbM Hyde Park. These data were confirmed by molecular analysis (Southern blot and DNA sequencing). Neither the parents nor a sister showed any abnormality; non-paternity was excluded by blood group serology and HLA typing. CONCLUSIONS: This is a case of HbM Hyde-Park arising as a de novo mutation. FAB mass spectroscopic analysis is a rapid and useful analytical method for identifying aminoacid substitution.

Molecular basis of chronic non-spherocytic haemolytic anaemia: a new G6PD variant (393 Arg----His) with abnormal KmG6P and marked in vivo instability.

More than 80 genetic variants of glucose-6-phosphate dehydrogenase (G6PD) are associated with chronic non-spherocytic haemolytic anaemia (CNSHA). In order to help clarify the molecular basis of this association, we have carried out a detailed biochemical and genetic characterization of two G6PD deficient brothers affected by CNSHA. The G6PD from the two patients has altered electrophoretic mobility, abnormally elevated Michaelis constant (Km) for G6P, and extreme instability in vivo and in vitro. By comparison with published information we found that this is a new G6PD variant which we have designated G6PD Portici. The entire coding region of the gene has been sequenced, and a single point mutation, a G----A transition, was found at position 1178 in exon X, causing a substitution of histidine for arginine at residue 393 in the polypeptide chain. By polymerase chain reaction (PCR) amplification followed by diagnostic restriction enzyme analysis and allele-specific oligonucleotide hybridization we have demonstrated the inheritance of this mutation in the patient's family. Our results support the notion of a causative link between this mutation in the G6PD gene and CNSHA. Our data, in combination with previous data in the literature, suggest that the three-dimensional structure of G6PD is such as to cause interaction in the binding of its two substrates, G6P and NADP.

Iron absorption and iron deficiency in infants and children with gastrointestinal diseases.

Iron status, iron absorption, and intestinal blood loss were studied in 199 children undergoing diagnostic evaluation for suspected malabsorption. Evaluation of iron status included hematological indices, serum ferritin, and transferrin saturation. Iron absorption was assessed by the increment of serum iron after an oral iron load. Iron deficiency was common among patients affected by malabsorptive states, such as celiac disease (84%), cow's milk intolerance (76%), Crohn's disease (72%), and giardiasis (64%), whereas it was less common among patients with postinfectious enteritis (41%) and chronic nonspecific diarrhea (11%). Intestinal blood loss was seen only in patients with Crohn's disease and cow's milk intolerance, irrespective of iron nutritional status. On the other hand, iron malabsorption was very common, affecting 85-95% of the iron-deficient patients in all diagnostic groups, except in chronic nonspecific diarrhea. Iron malabsorption was less common among patients with adequate iron nutritional status than in those with iron deficiency. Iron malabsorption appears to play a major role in the pathogenesis of iron deficiency in patients with malabsorption. The iron absorption test shows greater sensitivity as a screening test for upper intestinal malabsorption than the D-xylose absorption test.