Does cystic fibrosis neonatal screening detect atypical CF forms? Extended genetic characterization and 4-year clinical follow-up.

The neonatal screening protocol for cystic fibrosis (CF) is based on a first determination of blood immunoreactive trypsin (IRT1), followed by a first level genetic test that includes the 31 worldwide most common mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene (DNA31), and a second determination of blood immunoreactive trypsin (IRT2). This approach identifies, in addition to affected subjects, a high proportion of newborns with hypertrypsinaemia at birth, in whom only one mutation is identified and who have a negative or borderline sweat test and pancreatic sufficiency. Although it has been suggested that hypertrypsinaemia may be caused by a single CFTR mutation, whether such neonates should be merely considered as healthy carriers remains a matter of debate as hypertrypsinaemia at birth may be a biochemical marker of a CFTR malfunction because of a second mild mutation. We analyzed, by means of an extended sequencing protocol, 32 newborns who tested positive at an IRT1/DNA31/IRT2 screening protocol and in whom only one CFTR mutation was found. The results obtained demonstrate that 62.5% of these newborns were also carrying a second mild CFTR mutation. The high proportion of compound heterozygous subjects, combined with the results of a 4-year follow-up in nine of these subjects all of whom displaying initial CF clinical symptoms, suggest that it may be possible to use the IRT1/DNA31/IRT2 protocol of neonatal screening to identify newborns with atypical forms of CF. In view of these findings, an extended genetic search for subjects with compound heterozygosity and a periodic clinical assessment should be considered.

A functional study of plasma-membrane calcium-pump isoform 2 mutants causing digenic deafness.

Ca2+ enters the stereocilia of hair cells through mechanoelectrical transduction channels opened by the deflection of the hair bundle and is exported back to endolymph by an unusual splicing isoform (w/a) of plasma-membrane calcium-pump isoform 2 (PMCA2). Ablation or missense mutations of the pump cause deafness, as described for the G283S mutation in the deafwaddler (dfw) mouse. A deafness-inducing missense mutation of PMCA2 (G293S) has been identified in a human family. The family also was screened for mutations in cadherin 23, which accentuated hearing loss in a previously described human family with a PMCA2 mutation. A T1999S substitution was detected in the cadherin 23 gene of the healthy father and affected son but not in that of the unaffected mother, who presented instead the PMCA2 mutation. The w/a isoform was overexpressed in CHO cells. At variance with the other PMCA2 isoforms, it became activated only marginally when exposed to a Ca2+ pulse. The G293S and G283S mutations delayed the dissipation of Ca2+ transients induced in CHO cells by InsP3. In organotypic cultures, Ca2+ imaging of vestibular hair cells showed that the dissipation of stereociliary Ca2+ transients induced by Ca2+ uncaging was compromised in the dfw and PMCA2 knockout mice, as was the sensitivity of the mechanoelectrical transduction channels to hair bundle displacement in cochlear hair cells.

Comparison of two different protocols of neonatal screening for cystic fibrosis.

The results of two different protocols of neonatal cystic fibrosis (CF) screening in the Lazio region of Italy are reported. The first study, conducted from 1992 to 2000 on about 200,000 newborns, consisted of an immunoreactive trypsin (IRT) protocol without mutation analysis of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, referred to as the IRT/IRT protocol. Approximately 5% of the newborns with a positive first IRT test were also positive at the second test; approximately 57% of the newborns with a high IRT level at the second test were subsequently found to be affected by CF. In September 1998, a second protocol that included mutation analysis (IRT/DNA/IRT protocol) was started. Comparison of the two different screening protocols in terms of sensitivity in detecting CF patients demonstrated that the IRT/DNA/IRT protocol is more effective because it is able to detect a higher number of CF patients than the IRT/IRT protocol. In the same period, in addition to the overall diagnosis performed on a screening basis, 64 other subjects were identified as being affected by CF on the basis of symptomatic findings. The overall incidence of CF (screening + symptoms) was 1 : 2982, while that for carriers was 1 : 27. The sensitivity of the screening program increased over the period from 1992 to 2000, with the enhanced sensitivity in the past 2 years being due to the introduction of the IRT/DNA/IRT protocol.

Gradients of expression of calcium and potassium currents in frog crista ampullaris.

In the present work we studied the intraregional expression of voltage-dependent Ca2+ and K+ currents in hair cells of frog crista ampullaris. The currents were recorded in situ from sensory cells of the peripheral region, the most populated region of the crista, by using the whole-cell variant of the patch-clamp technique. Voltage-clamp recordings revealed that the calcium current (I(Ca)) and the outward potassium currents of I(A), I(K) I(KCa) types and the inward rectifier potassium current of I(K1) type exhibited a significant gradient of density (pA/pF) along the region. I(A) density was maximal in cells located at the beginning of the peripheral region and decreased gradually becoming very small at the opposite end. All the other currents showed an opposite gradient of expression. Current-clamp experiments showed that the voltage behaviour of hair cells changed in relation to cell position. Cells located at the beginning of the peripheral region showed large depolarizations from the resting potential (close to -45 mV) which are consistent with the presence of small I(K) and I(KCa), and an I(A) largely inactivated at rest. These cells also exhibited slowly developing and large hyperpolarizations that approached passive ones, due to the lack of I(K1). In contrast, cells located at the opposite side of the region showed smaller depolarizations and hyperpolarizations from the resting potential (close to -65 mV), due to the presence of large I(K) and I(KCa), and I(K1), respectively. The possible role of the intraregional variation of Ca2+ and K+ currents in both hair cell function and afferent discharge properties is discussed.

[Neonatal screening for cystic fibrosis]. / Screening neonatale per la fibrosi cistica.

Cystic fibrosis (C.F.), a congenital lethal disease involving many organs, is responsible of chronic pulmonary disease and maldigestion. At the beginning symptoms can be feeble and diagnosis is often delayed, especially in those cases with an isolated pulmonary expression. It is demonstrated that early diagnosis and immediate prophylaxis of pulmonary infections and maldigestion improves survival. Thus a neonatal screening test is required. Although various attempts have been done, dating from 1968, there is no evidence, up to now, of a real utility of neonatal screening tests in C.F. The only test with a minor frequency of false negatives and positives is the RIA trypsin serum dosage to be executed within 3-5 days of life.

[Vaccination against hepatitis B in childhood as possible means of infection control]. / Vaccinazione contro l'epatite B in età pediatrica come possibile strumento di controllo dell'infezione.

A follow-up of 21 months was conducted in order to evaluate the efficacy of vaccination against Hepatitis B Virus in a group of 54 children (age 2-14) belonging to family cluster characterized by the presence of HBsAg healthy carriers. HB-VAX, plasma-derived, and Engerix B, by a recombinant DNA technique, were both employed and administered with the following schedule: three doses of 0, 1 and 6 months. Out of 54 subjects, 48 completed the follow-up. These children all presented a good immune response as assessed at 1 and 12 months after the last administration. The results obtained show that this vaccination, free from side effects, is the most efficacious and safest tool to control the spread of Hepatitis B Virus infection and its complications at short and long term, especially when carried out on a large scale.

[Paravertebral block of the lumbar plexus. Variations of the original technic]. / Blocco del plesso lombare per via paravertebrale. Variante alla metodica originale.

After studying a hundred or so abdominal CT scans carried out at L5 level and having verified that the interfascial compartment between the quadrate muscle of the lumbi and the psoas muscle is relatively fixed (1.8-2.3 cm), it is proposed to utilise this datum (introduction of the 2 cm) needle after contact with the transverse apophysis of L5) to identify the psoas compartment which contains most of the nerves making up the lumbar plexus. Study of the series and results obtained confirm the value and simplicity of the proposed technique.

[Incidence and severity of postoperative anemia in elderly patients treated with Ender intramedullary nails]. / Incidenza e gravità dell'anemia postoperatoria nel paziente geriatrico trattato con chiodi endomidollari di Ender.

Stress is laid on the state of progressive anaemia that follows osteosynthesis with Ender intramedullary nails in elderly patients suffering from femoral pertrochanteric fracture. The behaviour of haemochromocytometric values has been examined in a series of 56 female patients aged more than 75, from the time of admission to the fourth day subsequent to surgery: in sharp contrast with the minor trauma triggered by the operation, a significant reduction was observed in haemoglobinaemia and in haematocrit value. Attempting, hypothetically, to give a plausible justification to these results, it is concluded by recommending careful clinical and laboratory control during the days immediately following the operation.

Surgical treatment of isthmic spondylolisthesis in adults. Review of 44 cases with long-term control.

The results are presented of 44 cases of isthmic spondylolisthesis in adults treated surgically. The Authors consider three groups treated by: A) surgery to free the nerve roots, B) posterior fusion with or without freeing of the nerve roots, C) posteriorlateral fusion. After an analysis of the techniques at present in use for the treatment of spondylolisthesis, the Authors conclude that, in adults, posteriorlateral fusion produces a high percentage of successes with low risk.

Effect of hycanthone on Schistosoma mansoni macromolecular synthesis in vitro.

Adult, immature and hycanthone-resistant schistosomes were allowed to incorporate tritiated precursors of macromolecule synthesis in vitro, either in the presence of various concentrations of hycanthone, or at various times after removal of the drug. The effect on worms was compared to that on HeLa cells. The results show that hycanthone markedly inhibited the incorporation of uridine in all the systems studied, while the incorporation of thymidine and leucine was only secondarily affected. The inhibition of uridine incorporation reflected in part a decreased uptake of the radioactive precursor. The hycanthone-induced inhibition of uridine incorporation was essentially irreversible upon removal of the drug in adult schistosomes, while it was completely reversible in hycanthone-resistant worms, in immature worms and in HeLa cells. The effects of a hycanthone analog, IA-4, were largely comparable to the effects of the parent compound. These results suggest that the inhibition of RNA synthesis can be a possible explanation for the mechanism of the schistosomicidal action of hycanthone.