Lung Ultrasound and High-Resolution Computed Tomography in Suspected COVID-19 Patients Admitted to the Emergency Department: A Comparison

Objective

To analyze the diagnostic accuracy of lung ultrasonography (LUS) and high-resolution computed tomography (HRCT), to detect COVID-19.

Materials and Methods

This study recruited all patients admitted to the emergency medicine unit, due to a suspected COVID-19 infection, during the first wave of the COVID-19 pandemic. These patients also who underwent a standardized LUS examination and a chest HRCT. The signs detected by both LUS and HRCT were reported, as well as the sensitivity, specificity, positive predictive value, and negative predictive value for LUS and HRCT.

Results

This cohort included 159 patients, 101 (63%) were diagnosed with COVID-19. COVID-19 patients showed more often confluent subpleural consolidations and parenchymal consolidations in lower lung regions of LUS. They also had "ground glass" opacities and "crazy paving" on HRCT, while pleural effusion and pulmonary consolidations were more common in non-COVID-19 patients. LUS had a sensitivity of 0.97 (95% CI 0.92-0.99) and a specificity of 0.24 (95% CI 0.07-0.5) for COVID-19 lung infections. HRCT abnormalities resulted in a 0.98 sensitivity (95% CI 0.92-0.99) and 0.1 specificity (95% CI 0.04-0.23) for COVID-19 lung infections.

Conclusion

In this cohort, LUS proved to be a noninvasive, diagnostic tool with high sensitivity for lung abnormalities that were likewise detected by HRCT. Furthermore, LUS, despite its lower specificity, has a high sensitivity for COVID-19, which could prove to be as effective as HRCT in excluding a COVID-19 lung infection.

Impact of the environment on the health: From theory to practice

The Erice 56 Charter titled "Impact of the environment on the health: from theory to practice" was unanimously approved at the end of the 56th course of the "International School of Epidemiology and Preventive Medicine G. D'Alessandro" held from 3rd to November 7, 2019 in Erice - Sicily (Italy) and promoted by the Study Group of "Environment and Health" of the Italian Society of Hygiene, Preventive Medicine and Public Health. The course, that included lectures, open discussions and guided working groups, was aimed to provide a general training on epidemiological and toxicological aspects of the environmental health impact, to be used by public health professionals for risk assessment, without forgetting the risk communications. At the end of the course 12 key points were agreed among teachers and students: they underlined the need of specific training and research, in the perspective of "One Health" and "Global Health", also facing emerging scientific and methodological issues and focusing on communication towards stakeholders. This Discussion highlight the need to improve knowledge of Health and Environment topic in all sectors of health and environmental prevention and management.

Genetic interaction analysis of VEGF-A rs3025039 and VEGFR-2 rs2071559 identifies a genetic profile at higher risk to develop nodular goiter

CONTEXT

Nodular goiter in patients from areas of iodine deficiency is due to the growth of follicular and endothelial cells, involving different vascular-related growth factors in its pathogenesis.

OBJECTIVE

The aim of our study was to examine the association of known single polymorphisms of vascular endothelial growth factor-A [VEGF-A], VEGF receptor-2 [VEGFR-2] and hypoxia-inducible factor-1α [HIF-1α] genes or their genetic interactions with the risk of nodular goiter development.

PATIENTS AND METHODS

116 normal subjects, without any thyroid disease, and 108 subjects with nodular goiter [subjects with goiter and at least one thyroid nodule of > 1 cm of maximum size and in absence of signs of autoimmunity] were selected from a homogeneous population living in a mild iodine deficiency geographic area. Analyses were performed on germline DNA obtained from blood samples and VEGF-A rs3025039, VEGFR-2 rs2071559, and HIF-1αrs11549465 SNPs were investigated by real-time PCR technique. The multifactor dimensionality reduction [MDR] methodology was applied to investigate the genetic interaction between SNPs. Hardy-Weinberg equilibrium was performed.

RESULTS

None of the studied polymorphisms were individually associated with a higher risk to develop nodular goiter [P > 0.05]. The combination of the VEGF-A rs3025039 and VEGFR-2 rs2071559 polymorphisms had the highest accuracy of 0.58 [P = 0.018] and the interaction of some genotypes was significantly associated with the risk of nodular goiter development.

CONCLUSIONS

Our results support a genetic interaction between the VEGF-A rs3025039 and VEGFR-2 rs2071559 polymorphisms as a predictor of the risk to develop nodular goiter in subjects coming from an area with mild iodine deficiency.

Inertial waves and mean velocity profiles in a rotating pipe and a circular annulus with axial flow

In this paper we solve the inviscid inertial wave solutions in a circular pipe or annulus rotating constantly about its axis with moderate angular speed. The solutions are constructed by the so-called helical wave functions. We reveal that the mean velocity profiles must satisfy certain conditions to accommodate the inertial waves at the bulk region away from boundary. These conditions require the axial and azimuthal components of the mean velocity to take the shapes of the zeroth and first order Bessel functions of the first kind, respectively. The theory is then verified by data obtained from direct numerical simulations for both rotating pipe and circular annulus, and excellent agreement is found between theory and numerical results. Large scale vortex clusters are found in the bulk region where the mean velocity profiles match the theoretical predictions. The success of the theory in rotating pipe, circular annulus, and streamwise rotating channel suggests that such inertial waves are quite common in wall bounded flow with background rotation.

The role of red blood cell scintigraphy in the multiple-modality imaging diagnosis of a rare case of diffuse hepatic hemangiomatosis in an adult

Introduction: Angiomas are one of the most common primary tumors of the liver. Diffuse hepatic angiomatosis, however, is quite rare and usually observed in pediatric patients. We report a rare case of diffuse hepatic hemangiomatosis in a 33-year-old woman. Case report: The patient presented with abdominal pain and a palpable upper abdominal mass. Abdominal CT and magnetic resonance imaging (MRI) findings suggested diffuse hepatic hemangiomatosis, but this finding was not confirmed by subsequent contrast-enhanced abdominal ultrasonography (US). The patient then underwent single photon emission computed tomography (SPECT)/CT scintigraphy with Tc-99m-labeling of red blood cells (RBC). This examination revealed increased uptake of labeled erythrocytes in several of the hepatic lesions corresponding to CT and RM findings, thereby confirming the clinical hypothesis of diffuse hepatic hemangiomatosis. Discussion: RBC scintigraphy with SPECT/CT can facilitate the comparison of other crosssectional imaging methods such as CT and MRI. This case highlights the importance of a multiple-modality approach in the imaging diagnosis of this condition.

Comparative modular analysis of two complex sulfosalt structures: sterryite, Cu(Ag,Cu)3Pb19(Sb,As)22(As–As)S56, and parasterryite, Ag4Pb20(Sb,As)24S58

The crystal structures of two very close, but distinct complex minerals of the lead sulfosalt group have been solved: sterryite, Cu(Ag,Cu)3Pb19(Sb,As)22(As–As)S56, and parasterryite, Ag4Pb20(Sb,As)24S58. They are analyzed and compared according to modular analysis. The fundamental building block is a complex column centred on a Pb6S12 triangular prismatic core, with two additional long and short arms. The main chemical and topological differences relate to the short arm, which induces a relative a/4 shift (∼ 2 Å along the elongation parameter) of the constitutive rod layers, as illustrated by distinct cell settings within the same space group (P21/n and P21/c, respectively). Selection of the shortest (i.e. strongest) (Sb,As)—S bonds permitted to enhance the polymeric organization of (Sb,As) atoms with triangular pyramidal coordination. These two quasi-homeotypic structures are expanded derivatives of owyheeite, Ag3Pb10Sb11S28. The hierarchy of organization levels from zero- to three-dimensional entities is subordinated to building operators, which appear as the driving force for the construction of such complex structures. Minor cations (Ag, Cu) or the As–As pair in sterryite secure the final locking, which favours the formation of one or the other compound.

Antibodies to the Plasmodium falciparum rhoptry protein RAP-2/RSP-2 in relation to anaemia in Cameroonian children

Previous studies have implicated reactive antibodies to the low molecular weight rhoptry-associated proteins (RAP-1, RAP-2/RSP-2 and RAP-3) in erythroid cell destruction during Plasmodium falciparum infection. In this pilot study, the frequency, specificity and functional capacity of naturally acquired anti-RAP-2/RSP-2 antibodies were investigated in the sera of anaemic and nonanaemic malaria-infected Cameroonian children. All sera recognized RAP-2/RSP-2 by FACS, irrespective of the clinical status of the subjects. However, the anaemic children showed higher levels of IgG antibodies than the nonanaemic group, while both groups showed similar levels of IgM antibodies. Only few individuals had detectable levels of RAP-2/RSP-2-specific IgG1 and IgG3 subclass antibodies, while no IgG2 and IgG4 subclass antibodies were detected in these subjects. By ELISA, the anaemic group tended to show higher levels of antibodies to RAP-2/RSP-2 regarding all antibody classes tested, except for IgG4 and IgE. Unexpectedly, sera from the nonanaemic group activated complement to a greater extent than those from the anaemic group. These results need to be confirmed in extended studies but indicate that the effector functions of the RAP-2/RSP-2-reactive antibodies may be more important than their amounts. Such antibodies could play a role in both immunity and pathogenesis during P. falciparum infection.

Pharmacodynamic and pharmacogenetic angiogenesis-related markers of first-line FOLFOXIRI plus bevacizumab schedule in metastatic colorectal cancer

Background:

The identification of molecular and genetic markers to predict or monitor the efficacy of bevacizumab (BV) represents a key issue in the treatment of metastatic colorectal cancer (mCRC).

Methods:

Plasma levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble VEGF receptor 2 (sVEGFR-2) and thrombospondin-1 (TSP-1) were assessed by ELISA assay at different time points in a cohort of 25 patients enroled in a phase II trial of GONO-FOLFOXIRI plus BV as first-line treatment of mCRC. VEGF: −2578A/C, −1498C/T, −1154A/G, −634C/G and 936C/T; and VEGFR-2: −604A/G, +1192C/T and +1719A/T, polymorphisms were assessed in a total of 54 patients.

Results:

Treatment with GONO-FOLFOXIRI plus BV determined a prolonged and significant reduction in plasma free, biologically active VEGF concentration. Interestingly, VEGF concentrations remained lower than at baseline also at the time of PD. Conversely, PlGF levels increased during the treatment if compared with baseline, suggesting a possible role in tumour resistance; moreover, sVEGFR-2 increased at the time of PD, as well as TSP-1. No association of assessed polymorphisms with outcome was found.

Conclusion:

Our study suggested the possible mechanisms of resistance to combined therapy in those patients with a progressive disease to be tested in ongoing phase III randomised studies.

Sarcoidosis in the setting of idiopathic chronic bronchiolitis with airway colonization from P. aeruginosa: treatment with low-dose macrolides

It has long been suggested that infectious agents may trigger sarcoidosis through their infectious or antigenic properties. A patient with airway colonization from P. aeruginosa in the setting of idiopathic bronchiolitis (IB) mimicking diffuse panbronchiolitis (DPB) developed sarcoidosis. Impressive clinical and radiological improvement of both bronchiolitis and sarcoidosis features was achieved with a one-year treatment with low-dose erythromycin, thus suggesting a possible link between the two conditions in this specific case. Pathogenic hypotheses and therapeutic implications are specifically discussed.

In vitro antiangiogenic activity of selective somatostatin subtype-1 receptor agonists

BACKGROUND

Endothelial cells of human blood vessels (arteries and veins) show high levels of somatostatin subtype-1 receptor (sst(1)). The aim of the present study is to investigate the inhibitory effects of novel somatostatin analogs, highly selective for human sst(1), on in vitro angiogenesis and their modulation of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-2 (VEGFR-2) expression.

MATERIALS AND METHODS

Somatostatin analogs BIM-23745 and BIM-23926 were tested for their ability to prevent proliferation and migration of human endothelial HMEC-1 cells, to modulate VEGF and VEGFR-2 expression and to inhibit sprouting of microvessels from cultured human placental vessel explants in fibrin matrix for 28 days.

RESULTS

The somatostatin sst(1 )receptor-selective agonists, BIM-23745 and BIM-23926 showed a suppression of endothelial proliferation (e.g. 10(-6) M BIM-23475, 40.0 +/- 2.1% vs. 100% of controls; 10(-7) M BIM-23926, 55.3 +/- 3.3% vs. 100% of controls), migration (e.g. 10(-7) M BIM-23475, 35.0 +/- 1.56% vs. 100% of controls; 10(-7) M BIM-23926, 53.7 +/- 1.77% vs. 100% of controls) and microvessel sprouting (e.g. 10(-8) M BIM-23475, 42.8 +/- 5.6% vs. 100% of controls; 10(-7) M BIM-23926, 17.2 +/- 11.8% vs. 100% of controls). A small but significant percentage of cells exposed to BIM-23745 and BIM-23926 for 24 h and for 72 h presented typical apoptotic morphology. Moreover, both the analogs significantly inhibit VEGF and VEGFR-2 gene expression in endothelial cells grown for 144 h in a fibrin matrix and the VEGF secretion in conditioned media.

CONCLUSIONS

The inhibition of endothelial activities suggests potential therapeutic utility for administration of somatostatin sst(1 )receptor-selective agonists in the proliferative diseases involving angiogenesis.

Airway obstruction during arthroscopic shoulder surgery: anesthesia for the patient or for the surgeon?

Two cases of airway obstruction as a result of oedema of laryngeal structures which arose during protracted arthroscopic shoulder surgery, in which single-shot interscalene blocks had been performed, are reported. In these 2 cases, the complexity of the pathologies and the fact that the surgeons were at the beginning of their surgical experience are the most likely causes of the conditions which led to tracheal compression from extra-articular leakage of fluid. Therefore, we recommend a combined peripheral block and general anaesthesia with tracheal intubation for procedures performed by surgeons without an adequate experience and on obese patients, patients placed in a lateral decubitus, or procedures in which difficulties are expected. The advantages of regional anaesthesia with a constant control of the airways are underlined.

Metronomic chemotherapy (MC) with irinotecan (CPT-11) in patients with diagnosis of metastatic colorectal cancer (MCRC): clinical and pharmacodynamic evaluation

13111

Background: Preclinical studies have demonstrated that the frequent administration of low doses of cytotoxic drugs over prolonged periods of time (MC) reduces tumour cell growth through inhibition of angiogenesis. The antitumor effect of a MC with cyclophosphamide is due to an increase of thrombospondin-1 (TSP-1) plasma level, an endogenous inhibitor of angiogenesis. Methods: An exploratory study was conducted to assess the feasibility, the activity and the optimal metronomic dose of CPT-11 when administered as protracted continuous infusion (c.i.) in pretreated MCRC. A pharmacodynamic evaluation of anti- and pro-angiogenic factors, such as TSP-1 and vascular endothelial growth factor (VEGF), was performed. Weekly blood samples were taken. Three different CPT-11 dose levels have been evaluated: 1.4, 2.8 and 4.2 mg/sqm/day; 25%, 50% and 75% of the maximum CPT-11 tolerated dose in c.i. (5.6 mg/sqm/day), respectively. Results: Between Apr 04 and May 05 20 patients have been enrolled. Patients characteristics were: M/F = 11/9, median age = 71 years (range 51–79); PS 0/1/2 = 8/11/1; sites of metastasis: single/multiple = 7/13; median of previous lines of chemotherapy: 3 (range 1–5). No toxicities of grade >1 NCI scale have been observed. No objective responses were observed, but 4 patients (20%) had a stable disease with a median duration of 14 weeks (range 11–20). TSP-1 plasma levels significantly increased after one week and remained higher than the baseline for more than 8 weeks (120.1±10.3% vs. 100% of day 0). VEGF levels did not significantly change during the CPT-11 infusion. No statistical differences have been found for TSP-1 and VEGF concentrations among the three dose levels. Conclusions: CPT-11 metronomic chemotherapy is feasible. Plasma TSP-1 markedly increased during metronomic CPT-11 administration, suggesting a modulation of the angiogenic process in cancer patients. Supported by A.I.R.C.

[Table: see text]

Idarubicin and idarubicinol effects on breast cancer multicellular spheroids

Despite extensive preclinical evaluation in several experimental models, no studies have determined the effect of idarubicin and its metabolite idarubicinol on multicellular spheroids, a model which mimics the microregions of solid tumors. The principal aim of the present study was to investigate the in vitro cytotoxicity of idarubicin and its metabolite idarubicinol on MCF-7 breast cancer cells growing as monolayers or multicellular spheroids and to evaluate the influence of the length of exposure on the cytotoxic effect of both drugs. Cytoxicity was evaluated on monolayer and spheroid cultures exposed to idarubicin and idarubicinol 0.01-1000 ng/ml for 24 h or treated for 6, 12, 24 and 48 h to 100 ng/ml of both drugs. The IC50 of idarubicin and idarubicinol were 3.3+/-0.4 and 3.6+/-0.7 ng/ml, respectively, on MCF-7 monolayers and 7.9+/-1.1 and 5.3+/-0.7 ng/ml in multicellular spheroids, respectively. The antiproliferative effects of 100 ng/ml idarubicin and idarubicinol on MCF-7 spheroids was characterized by a marked time-dependence, which was less evident on MCF-7 growing as monolayer. In conclusion, the present experimental data demonstrate, for the first time, that idarubicin and idarubicinol have significant cytotoxic activity against multicellular spheroids, comparable to the antiproliferative effects on monolayer cells. In contrast, spheroids displayed substantial resistance after short exposure times that was not present in the two dimensional cultures.

Fluvastatin synergistically enhances the antiproliferative effect of gemcitabine in human pancreatic cancer MIAPaCa-2 cells

The new combination between the nucleoside analogue gemcitabine and the cholesterol-lowering drug fluvastatin was investigated in vitro and in vivo on the human pancreatic tumour cell line MIAPaCa-2. The present study demonstrates that fluvastatin inhibits proliferation, induces apoptosis in pancreatic cancer cells harbouring a p21ras mutation at codon 12 and synergistically potentiates the cytotoxic effect of gemcitabine. The pharmacologic activities of fluvastatin are prevented by administration of mevalonic acid, suggesting that the shown inhibition of geranyl-geranylation and farnesylation of cellular proteins, including p21rhoA and p21ras, plays a major role in its anticancer effect. Fluvastatin treatment also indirectly inhibits the phosphorylation of p42ERK2/mitogen-activated protein kinase, the cellular effector of ras and other signal transduction peptides. Moreover, fluvastatin administration significantly increases the expression of the deoxycytidine kinase, the enzyme required for the activation of gemcitabine, and simultaneously reduces the 5′-nucleotidase, responsible for deactivation of gemcitabine, suggesting a possible additional role of these enzymes in the enhanced cytotoxic activity of gemcitabine. Finally, a significant in vivo antitumour effect on MIAPaCa-2 xenografts was observed with the simultaneous combination of fluvastatin and gemcitabine, resulting in an almost complete suppression and a marked delay in relapse of tumour growth. In conclusion, the combination of fluvastatin and gemcitabine is an effective cytotoxic, proapoptotic treatment in vitro and in vivo against MIAPaCa-2 cells by a mechanism of action mediated, at least in part, by the inhibition of p21ras and rhoA prenylation. The obtained experimental findings might constitute the basis for a novel translational research in humans.

Insight into B cell development and differentiation

The main topic of this article is B cell development and differentiation, with a special focus on the mechanisms and molecules that regulate the expression of humoral immunity. Molecular epidemiological analysis was performed on the genes responsible for the X-linked agammaglobulinemia (XLA) phenotype of the majority of Italian patients and their distinct mutations were characterized. Mutations in Bruton's tyrosine kinase (BTK), a member of Tec Family of protein tyrosine kinases, have been found to be mainly responsible for XLA disease. The exact function of BTK in signal transduction is not yet known; thus, the specific role of BTK in receptor-dependent calcium signaling and the pro-antiapoptotic regulatory activity was addressed by transfecting RAMOS-1, a BTK-deficient human Burkitt's/B cell leukemia line with wild-type and mutant constructs. This work may provide clues about critical sites in the molecule and give support for gene therapy as a potential successful approach to XLA. Another aspect of this research is the identification and dissection of the molecular events that are likely to be directly related to the ability to express various isotypes of immunoglobulin with differing function and certain B cell immunodeficiency, mainly common variable disease and non-X-linked hyperIgM. B cell development and maturation steps in different compartments of the immune system are tracked by the analysis of cell-surface molecules and components of the signal transduction pathways, i.e. CD40, CD30, CD27, CD38, CD22 and CD24. A few components involved in B cell development, maturation and differentiation and their specific functional role are at least partially known, but these are far from fitting into an understandable pathway at present.

Bruton's tyrosine kinase defect in dendritic cells from X-linked agammaglobulinaemia patients does not influence their differentiation, maturation and antigen-presenting cell function

X-linked agammaglobulinaemia (XLA) is a primary immunodeficiency disease characterized by very low levels or even absence of circulating antibodies. The immunological defect is caused by deletions or mutations of Bruton's tyrosine kinase gene (Btk), whose product is critically involved in the maturation of pre-B lymphocytes into mature B cells. Btk is expressed not only in B lymphocytes but also in cells of the myeloid lineage, including dendritic cells (DC). These cells are professional antigen presenting cells (APC) that play a fundamental role in the induction and regulation of T-cell responses. In this study, we analysed differentiation, maturation, and antigen-presenting function of DC derived from XLA patients (XLA-DC) as compared to DC from age-matched healthy subjects (healthy-DC). We found that XLA-DC normally differentiate from monocyte precursors and mature in response to lipopolysaccharide (LPS) as assessed by de novo expression of CD83, up-regulation of MHC class II, B7.1 and B7.2 molecules as well as interleukin (IL)-12 and IL-10 production. In addition, we demonstrated that LPS stimulated XLA-DC acquire the ability to prime naïve T cells and to polarize them toward a Th1 phenotype, as observed in DC from healthy donors stimulated in the same conditions. In conclusion, these data indicate that Btk defect is not involved in DC differentiation and maturation, and that XLA-DC can act as fully competent antigen presenting cells in T cell-mediated immune responses.

[Bilateral stenosis of the innominate veins in oncological patient]

Oncologic diseases frequently need a central venous catheterization to improve pharmacological administration safety and patient's comfort. We report a case of a woman affected by acute myelocytic leukemia with a bilateral stenosis of the innominate veins, likely of thrombotic nature, diagnosed during central venous catheterization. These events, as that occurred to our patient, are usually caused by hypercoagulability inducted by oncologic diseases, sepsis, antithrombin III deficiency, catheters materials and repeated catheterizations. Although the treatment, based on local thrombolysis, systemic heparinization, and surgery to repair venous obstruction, is effective, the prevention of such events is fundamental. It can be achieved with catheters of particular characteristics and appropriate management techniques. Finally it is underlined that in oncology patients, before catheterization, especially when the objective examination is negative, radiological methodologies and in particular ultrasonography are an important aid to establish the presence or absence of thrombosis in internal jugular, subclavian and innominate veins.

Promising early outcomes with a novel, complete steroid avoidance immunosuppression protocol in pediatric renal transplantation

BACKGROUND

Corticosteroids have been a cornerstone of immunosuppression for four decades despite their adverse side effects. Past attempts at steroid withdrawal in pediatric renal transplantation have had little success. This study tests the hypothesis that a complete steroid-free immunosuppressive protocol avoids steroid dependency for suppression of the immune response with its accompanying risk of acute rejection on steroid withdrawal.

METHODS

An open labeled prospective study of complete steroid avoidance immunosuppressive protocol was undertaken in 10 unsensitized pediatric recipients (ages 5-21 years; mean 14.4 years) of first renal allografts. Steroids were substituted with extended daclizumab use, in combination with tacrolimus and mycophenolate mofetil. Protocol biopsies were performed in the steroid-free group at 0, 1, 3, 6, and 12 months posttransplantation. Clinical outcomes were compared to a steroid-based group of 37 matched historical controls.

RESULTS

Graft and patient survival was 100% in both groups. Clinical acute rejection was absent in the steroid-free group at a mean follow-up time of 9 months (range 3-13.7 months). Protocol biopsies in the steroid-free group (includes 10 patients at 3 months, 7 at 6 months, and 4 at 12 months) revealed only two instances of mild (Banff 1A) subclinical rejection (reversed by only a nominal increase in immunosuppression) and no chronic rejection. At 6 months the steroid-free group had no hypertension requiring treatment (P=0.003), no hypercholesterolemia (P=0.007), and essentially no body disfigurement (P=0.0001). Serum creatinines, Schwartz GFR, and mean delta height Z scores trended better in the steroid-free group. In the steroid-free group, one patient had cytomegalovirus disease at 1 month and three had easily treated herpes simplex stomatitis, but with no significant increase in bacterial infections or rehospitalizations over the steroid-based group. The steroid-free group was more anemic early posttransplantation (P=0.004), suggesting an early role of steroids in erythrogenesis; erythropoietin use normalized hematocrits by 6 months.

CONCLUSIONS

Complete steroid-free immunosuppression is efficacious and safe in this selected group of children with no early clinical acute rejection episodes. This protocol avoids the morbid side effects of steroids without increasing infection, and may play a future critical role in avoiding noncompliance, although optimizing renal function and growth.

Chain of survival: differences in early access and early CPR between policemen and high-school students

Immediate activation of the emergency medical service (EMS) and cardiopulmonary resuscitation (CPR) increases the incidence of return of spontaneous circulation and the number discharged from hospital. The American Heart Association (AHA) and the European Resuscitation Council describe CPR as an ordinate sequence of eight steps. The objectives of this study were to assess the general knowledge of EMS and CPR and to analyse the retention of the CPR steps 2 months after a Basic Life Support (BLS)-course conducted according to AHA standards. We studied two populations from the same geographical area, law enforcement agents (LEA), since they are often the first to intervene, and high school students (HSS) since they are more likely to participate in such courses. HSS were more responsive and receptive than LEA. In order to increase the retention of the sequence of CPR steps, the number of steps should be reduced and refresher courses should be included in training programmes. Early access and early CPR are still not completely effective in the geographical area studied.

A 100% 2-year graft survival can be attained in high-risk 15-kg or smaller infant recipients of kidney allografts

BACKGROUND

Infants make up the most high-risk, difficult to care for subgroup undergoing kidney transplantation, with the lowest 1- and 2-year graft survival rates of any other age group. The principal causes of graft loss have been graft thrombosis, primary nonfunction, technical error, and irreversible acute rejection.

HYPOTHESIS

Infants undergoing kidney transplantation can achieve near 100% graft survival at 2 years following surgery, despite their very high-risk status.

DESIGN

Analysis of 45 consecutive kidney transplants performed in patients weighing less than or equal to 15 kg during an 8-year period beginning August 1991. Patients included complex referrals from throughout the United States and all received transplants and were cared for by the same pediatric kidney transplantation team.

RESULTS

Mean weight at transplantation was 11. 2 kg. Renal failure was due to congenital or urologic causes in the majority (53%) of cases. Size-discrepant adult-sized kidney grafts were transplanted in 80% of patients; 64% received live-donor grafts; 78% were receiving dialysis prior to transplantation; and 27% had extremely small bladders (<20 cm(3)) requiring modification of the ureteral implantation. Excluding 1 transplant-unrelated death, graft and patient survival at 2 years was 100%. Eight-year patient and graft survival rates (for our combined live and cadaver donor series) were 89.6% and 84.6%, respectively. This compares favorably with much lower graft survival in low-risk adult recipients. Delayed graft function occurred in only 1 patient (2%). Rate of incidence of rejection was 9.3% within 2 years of transplantation and the overall rejection rate was 15.5%. No graft was lost to vascular thrombosis, primary nonfunction, technical error, or acute rejection. The mean creatinine level was 53.04 micromol/L (0.6 mg/dL) and 61.9 micromol/L (0.7 mg/dL) at 1 and 2 years, respectively, and 88.4 micromol/L (1.0 mg/dL) at 3, 4, and 5 years after transplantation.

CONCLUSION

One hundred percent 2-year and excellent 8-year graft survival rates can be achieved in what has historically been the highest-risk and most difficult to care for patient subgroup undergoing kidney transplantation.

X-chromosome inactivation and mutation pattern in the Bruton's tyrosine kinase gene in patients with X-linked agammaglobulinemia. Italian XLA Collaborative Group

BACKGROUND

The diagnosis of X-linked agammaglobulinemia (XLA) is not always clearcut. Not all XLA conform to the classic phenotype and less than 50% of affected boys have a family history of immunodeficiency. Mutations in the gene for Bruton's tyrosine kinase (BTK) are responsible for the majority of agammaglobulinemia cases. However, a certain proportion of patients may have mutations involving other genes, although they show with an XLA phenotype. We performed BTK gene mutation analysis in 37 males with presumed XLA and analyzed the pattern of X-chromosome inactivation (XCI) in 31 mothers to evaluate the relevance of these approaches to diagnosis and genetic counseling.

MATERIALS AND METHODS

Twenty affected males with a sporadic occurrence and 17 familial cases belonging to nine families were enrolled within the framework of the Italian Multicenter Clinical Study on XLA. We used non-isotopic RNase cleavage assay (NIRCA), followed by cDNA sequence determination to screen for BTK mutations and X-chromosome inactivation analysis for carrier detection.

RESULTS

Using the cDNA-based approach, the identification of BTK gene abnormalities confirmed the clinical diagnosis of XLA in 31 of 37 affected infants. Missense was the most frequent mutational event and the kinase domain was mostly involved. In addition, nine novel mutations were identified. In sporadic cases, BTK gene abnormalities were identified in 9 out of 10 patients whose mothers had a nonrandom pattern of XCI and in 5 out of 6 patients whose mother had a random pattern of XCI. With the exception of one family, all patients with a familial occurrence and born to mothers with a nonrandom pattern of XCI had mutations of the BTK gene.

CONCLUSIONS

Our findings indicate that in sporadic cases BTK gene sequencing is the only reliable tool for a definitive diagnosis of XLA and support XCI as the first diagnostic tool in the mothers of affected males in multiple generations. Furthermore, our molecular analysis confirms that 10-20% of BTK-unaltered patients have disorders caused by defects in other genes.

[The Italian Registry of Bone Marrow Donors]

Following a synthetic statement of the scientific, genetic and practical assumptions of the bone marrow transplantation (BMT) from marrow unrelated donor (MUD), which, in turn, have represented the basis for the establishment of the Italian Bone Marrow Donor Registry (IBMDR), the paper reports the registry activity on 30 November 1998. At that date, Italian volunteers were 232,876, number which put the IBMDR as the fourth registry all over the world and as the third in Europe. The mean age of the donors is 34 years, and this means that IBMDR is one of the youngest among international registries. Using Italian donors, 426 BMT, altogether, have been performed, (248 for Italian patients and 178 for foreign patients). Donor search activations performed by national and international transplant centres have been, at the same date, 5729 (1821 for Italian patients and 3908 for foreign patients). Operating standards and guidelines for all centres participating in the IBMDR are reported in this issue.

Identification of nine novel mutations in the Bruton's tyrosine kinase gene in X-linked agammaglobulinaemia patients

Mutations in the Bruton's tyrosine kinase (BTK ) gene are responsible for X-linked Agammaglobulinemia (XLA), an immunodeficiency caused by a block in B cell differentiation. Non Isotopic RNAse Cleavage Assay (NIRCA), followed by sequencing was used to screen for BTK mutations in 11 Italian XLA patients. Nine novel mutations were identified: 6 missense (Y39S, L512P, L512Q, R544G, S578Y, E589K), one non-sense (Q260X), one frameshift (1599-1602del GCGC) and one in-frame insertion (2037-2038insTTTTAG), that represents the first case of premature stop codon introduction in the BTK coding frame. These data support the high molecular heterogeneity of BTK gene in XLA disease and provide new insight to the diagnosis and to the role of BTK domain in XLA and in B cell signal transduction and development. Hum Mutat 15:117, 2000.

Prognostic value of a CCR5 defective allele in pediatric HIV-1 infection

BACKGROUND

A deletion of 32 base pairs in the CCR5 gene (delta32 CCR5) has been linked to resistance to HIV-1 infection in exposed adults and to the delay of disease progression in infected adults.

MATERIALS AND METHODS

To determine the role of delta32 CCR5 in disease progression of HIV-1 infected children born to seropositive mothers, we studied a polymerase chain reaction in 301 HIV-1 infected, 262 HIV-1 exposed-uninfected and 47 HIV-1 unexposed-uninfected children of Spanish and Italian origin. Infected children were further divided into two groups according to their rate of HIV-1 disease progression: rapid progressors who developed severe clinical and/or immunological conditions within the second year of life, and delayed progressors with any other evolution of disease. Among the latter were the long-term, non-progressors (LTNP) who presented with mild or no symptoms of HIV-1 infection above 8 years of age. Viral phenotype was studied for 45 delayed progressors.

RESULTS

No correlation was found between delta32 CCR5 and mother-to-child transmission of HIV-1. However, the frequency of the deletion was substantially higher in LTNP, compared with delayed (p = 0.019) and rapid progressors (p = 0.0003). In children carrying the delta32 CCRS mutation, the presence of MT-2 tropic virus isolate was associated with a severe immune suppression (p = 0.028); whereas, the presence of MT-2 negative viruses correlated with LTNP (p = 0.010).

CONCLUSIONS

Given the rapidity and simplicity of the assay, the delta32 CCR5 mutation may be a useful predictive marker to identify children with delayed disease progression who, consequently, may not require immediate antiretroviral treatment.

Neurosurgery restores late GH rise after glucose-induced suppression in cured acromegalics

OBJECTIVE AND DESIGN

A decrease of GH levels below 2 microg/l after an oral glucose tolerance test (OGTT) is still currently accepted as the gold standard for assessing cure in surgically treated acromegaly. Whether glucose-induced suppression of GH is accompanied by a restoration of normal GH late rebound has not yet been evaluated in this disease. In order to assess the restoration of normal GH regulation after removal of a pituitary adenoma, we have evaluated GH changes after an OGTT in a series of selected acromegalic patients (transsphenoidal surgery and lack of pituitary failure).

METHODS

Twenty-nine patients (13 male, 16 female, age range 27-70 years) entered the study. Their neuroradiological imaging before neurosurgery showed microadenoma in 7, intrasellar macroadenoma in 8 and macroadenoma with extrasellar extension in 14. Plasma GH levels were assayed up to 300 min after glucose administration (75 g p.o.) and IGF-I on basal samples.

RESULTS

Basal GH levels were below 5 microg/l in 20 patients and below 2 microg/l in 5 of these. Normal age-adjusted IGF-I levels were observed in 12 patients. GH values were suppressed below 2 microg/l during an OGTT in 13 patients, and below 1 microg/l in 7 of these. In 9 patients out of these 13, a marked rise in GH levels occurred after nadir. Baseline and nadir GH values of these 9 patients were not different from the corresponding values of the other 4 patients without OGTT-induced late GH peaks.

CONCLUSIONS

GH rebound after GH nadir occurs in acromegalic patients considered as cured on the basis of OGTT-induced GH suppression and/or IGF-I normalization. The restoration of this physiological response could be regarded as a marker of recovered/preserved integrity of the hypothalamic-pituitary axis. Even though the reason for this GH rebound has not yet been elucidated (GHRH discharge?/end of somatostatin inhibition?), the lack of late GH peak in the patients regarded as cured by the usual criteria could be due to injury to the pituitary stalk caused by the adenoma or by surgical manipulation.

Zidovudine therapy and HIV type 1 mutations in children with symptomatic HIV type 1 infection: effect of switching to didanosine or zidovudine plus didanosine therapy. Italian Multicenter Study Group on HIV Mutations in Children

Type and prevalence of zidovudine (ZDV) resistance mutations in HIV-1-infected children in clinically stable condition and on ZDV monotherapy were analyzed to evaluate the effect of switching to didanosine (ddI) monotherapy or to ZDV plus ddI on the pattern of mutations and on the clinical outcome. Monthly clinical and laboratory controls for HIV-1 infection status were performed; at enrollment and every 4 to 6 months after treatment randomization mutant proviral sequences were evaluated in all the children, whereas viral burden was performed only in a small subgroup of patients randomly selected in each of the three treatment groups. ZDV resistance-associated proviral DNA mutations were defined as low-level resistance (LLR) mutations or medium/high-level resistance (MHLR) mutations; clinical outcome was considered as stable or deteriorating. Results showed that at entry into the study the duration of ZDV therapy was significantly correlated with the presence of mutations, and that the level of resistance given by mutations was associated with the severity both of symptoms and immunodeficiency. After randomization to treatment, in patients with mutations that confer LLR a better clinical outcome with ddI monotherapy than with ZDV plus ddI and ZDV alone was observed in the subsequent 6 months, whereas in patients with mutations that confer MHLR no significant difference among the three treatment groups was found. Data showed also that levels of viral burden at the time of changing therapy are related to clinical outcome if measured by plasma viral load. These results suggest that genotypic resistance assays, together with viral load, may prove useful for rational treatment decisions both at the start of therapy and with failure.

Analysis of HIV-1 reverse transcriptase gene mutations in infected children treated with zidovudine

Prolonged treatment with antiretroviral agents directed against reverse transcription (RT) in patients with HIV-1 infection results in the emergence of virus variants with reduced sensitivity containing mutations in the HIV-1 RT gene. Development of zidovudine (ZDV)-related mutations was studied in a cohort of 24 vertically infected pediatric patients receiving ZDV therapy. Monthly clinical and immunologic evaluation was accompanied by direct sequencing of the HIV-1 RT gene every 4 months. A correlation was observed between the emergence of mutations and the duration of therapy. Mutation at codon 41 was found only in the presence of mutation at codon 215. The presence of the mutations Met41-->Leu and Thr215-->Tyr/Phe did not appear to be related to disease progression. These findings suggest that the mere presence of mutations in the HIV-1 RT gene alone during ZDV monotherapy is not a reliable prognostic marker in the absence of other clinical and virologic information.

Cabergoline in acromegaly: a renewed role for dopamine agonist treatment?

OBJECTIVE AND DESIGN

Eighteen active acromegalics entered a prospective open study with cabergoline (CAB), a dopaminergic drug much more potent than bromocriptine (Br).

METHODS

CAB was administered for 6 months at doses ranging between 0.5 mg twice weekly and 0.5 mg/day. Clinical-anamnestic characteristics of the patients were: (i) sensitivity to dopamine agonist drugs (10 patients); (ii) resistance to somatostatin analogs (SAs) (8 patients): (iii) intolerance to SA (3 patients). In 2 patients marked hyperprolactinemia was present.

RESULTS

Basal GH was 6.6 microg/l (2.2-50) (median (range)), and on treatment it was 3.5 microg/l (1.2-34) (P=0.013). The corresponding IGF-I values were 720 microg/l (410-1438) and 375 microg/l (167-1260) respectively (P=0.00001). Individual GH levels decreased below 2 microg/l in 5 patients, and between 2 and 5 microg/l in another 5 patients. IGF-I levels were suppressed below 50% of baseline in 8 patients and normal age-adjusted IGF-I values were reached in 5 patients (27% of the series). The retrospective comparison with previous chronic treatment with Br in the 10 suitable patients showed a greater effectiveness of CAB (IGF-I decrease on CAB treatment, 46.8%, on Br treatment, 31%, P=0.02). Adenoma shrank in the 3 patients whose pituitary imaging was repeated during CAB.

CONCLUSIONS

These results envisage that CAB may represent a worthy therapeutic tool in acromegalic patients, inducing a degree of IGF-I and GH suppression comparable to SAs, administered by the oral route and much less expensive.

Successful transplantation of adult-sized kidneys into infants requires maintenance of high aortic blood flow

BACKGROUND

Nationally, results of renal transplantation in infants are inferior to those in older children and adults. Within the infant group, best results are obtained with adult-sized kidneys (ASKs) rather than size-compatible pediatric kidneys. However, transplantation of ASKs into infants has an increased risk of acute tubular necrosis and graft loss from vascular thrombosis and primary nonfunction. The aim of this study was to define and understand the hemodynamic changes induced by ASK transplantation, so that outcomes of transplantation in infants can be improved.

METHODS

Nine hemodynamically stable and optimally hydrated infants were studied under a controlled sedation with cine phase-contrast magnetic resonance at three time periods: before transplantation, 8-12 days after transplantation, and 4-6 months after transplantation. Cross-sectional images of both the infant aorta and the adult transplant renal artery were obtained and blood flow was quantitated. Renal volumes were also obtained, and expected renal artery blood flow based on early posttransplant volume was calculated. In addition, renal artery blood flow was determined in 10 in situ native adult kidneys prior to donor nephrectomy. Supplemental nasogastric or gastrostomy tube feeding was carried out during the blood flow study period to optimize intravascular volume.

RESULTS

Mean infant aortic blood flows were 331+/-148 ml/min before transplantation, 761+/-272 ml/ min at 8-12 days after transplantation (P=0.0006 with pretransplant flow), and 665+/-138 ml/min at 4-6 months after transplantation (P=0.0001 with pretransplant flow). Mean transplanted renal artery flows were 385+/-158 ml/min at 8-12 days and 296+/-113 ml/min at 4-6 months after transplantation. Transplanted renal artery flows were less than prenephrectomy in situ donor renal artery blood flow (618+/-130 ml/min; P=0.02 and P=0.0003) and expected normal renal artery blood flow (666+/-87 ml/min; P=0.003 and P=0.001) at both 8-12 days and 4-6 months after transplantation. A 26% reduction in renal volume (P=0.003) occurred between the two postoperative time periods, and this paralleled the decrease in posttransplant renal artery flow. One-year graft and patient survival in the nine infants was 100%. The mean serum creatinine levels at 3, 6, and 12 months were 0.43+/-0.10, 0.48+/-0.15, and 0.49+/-0.16 mg/dl.

CONCLUSIONS

This study is the first to quantitatively document the blood flow changes occurring after ASK transplantation in infants. There was a greater than two-fold increase in aortic blood flow after ASK transplantation, and this increase was sustained for at least 4 months and appeared to be driven by the blood flow demand of the ASK. However, actual posttransplant renal artery blood flow was significantly less than normal renal artery flow. Our study suggests that aggressive intravascular volume maintenance may be necessary to achieve and maintain optimum aortic blood flow, so as not to further compromise posttransplant renal artery flow and to avoid low-flow states that could induce acute tubular necrosis, vascular thrombosis, or primary nonfunction.

Scintigraphic imaging of pituitary adenomas: an in vivo evaluation of somatostatin receptors

We have performed pituitary scintigraphy with the somatostatin (SS) analog pentetreotidean by (111In-P) in patients with GH-secreting adenoma or with "clinically non functioning" adenoma (NFA) to evaluate the presence and the functionality of SS receptors (SS-R). 111In-P pituitary accumulation was expressed as Activity Ratio (AR): the ratio between the uptake of radioactivity by the adenoma and that of the normal brain tissue. In subjects without pituitary disease, AR ranged from 1.6 to 2.2 and a value lower than 2.2 was thus arbitrarily considered as normal. In 15 out of the 17 patients with GH-secreting adenoma, an accumulation of the radioligand was shown. Median AR was 3.8 (range 1-6.9; in 14 AR were greater that 2.2) and ARs were directly correlated (r = 0.54; p < 0.05) with the suppressibility of plasma GH levels by octreotide (OC) acute administration. In two patients who repeated scintigraphy during chronic OC treatment, AR values were reduced. In all the 22 patients with NFA an accumulation of 111In-P at the pituitary level was observed and median AR was 3.0 (range 1.5-20; in 14 greater that 2.2). In vitro autoradiography of surgical specimens in 6 NFA patients revealed SS-R in 4 cases with high scintigraphic AR and negative results in two cases with low AR. Scintiscan was repeated during chronic OC treatment in 5 patients with high score: AR decreased in one patient, increased in three, and did not change in the other patient. No changes in tumor size were shown in any of these patients. A total of 8 patients (3 GH secreting and 5 NFA) had "normal" AR values.

CONCLUSIONS

In acromegaly scintigraphy with 111In-P visualizes functioning pituitary SS-R coupled to intracellular events that control hormonal hypersecretion and tumor growth. In contrast, in spite of the positivity of 111In-P imaging in most patients with NFA, their receptors might have a defect in the coupling-transduction process, as they are not inhibited by OC treatment and no tumor shrinkage is observed.

Absence of Bruton's tyrosine kinase (Btk) mutations in patients with acute myeloid leukaemia

Bruton's tyrosine kinase (Btk) is a non-receptor protein tyrosine kinase (PTK) that is expressed in all haemopoietic lineages except mature T cells and plasma cells. Despite the broad range of expression. mutations that inactivate this molecule affect primarily the development of the B-cell lineage. As a PTK, Btk could potentially be involved directly or indirectly in the processes that relate to the malignant transformation of all the cell lineages where this molecule is expressed. Previous studies have failed to demonstrate mutations in patients with B-cell origin acute lymphoblastic leukaemia (ALL). We have utilized a recently developed method that enables the rapid and convenient detection of mutations at the cDNA level, namely, the non-isotopic RNase cleavage assay (NIRCA) to analyse Btk sequences from 27 patients with different types of acute myeloid leukaemia (AML). The only alteration that we observed was a polymorphism at position 2031. This polymorphism has already been seen in previous studies. Furthermore, using the same methodology, we identified the Btk mutations in six XLA (X-linked agammaglobulinaemia) patients. Our results, although they do not exclude the involvement of Btk mutations in the development or progression of some type of AML, nevertheless suggest that such mutations do not constitute a major co-factor in the development of myeloid malignancies.

HIV-1 nef mutations and clinical long-term nonprogression. A molecular epidemiology study

OBJECTIVES

To analyze HIV-1 nef gene mutations in a cohort of Italian and Swedish long-term nonprogressors (LTNP) and to investigate whether particular amino acid substitutions are associated with LTNP.

STUDY DESIGN/METHODS

nef alleles from 21 LTNP and 8 progressor controls were amplified by polymerase chain reaction (PCR) and sequenced. The amino acid sequences were compared with the previously reported sequences of 16 North American LTNP and of 28 patients with progressive infection.

RESULTS

An untruncated intact open reading frame was observed as major sequence in all LTNP and controls. None of the amino acid substitutions in known biologically functional sites was linked to LTNP. A valine/isoleucine at the variable position 11 was associated with both European (P = .0001) and American (P = .001) LTNP. The interpatient nef variation was lower among European LTNP (P = .002) than in European progressor controls.

CONCLUSIONS

Nef amino acid heterogeneity is lower among LTNP, probably reflecting the lower HIV-1 replication rate. Nef gene defects appear uncommon in both Swedish and Italian LTNP, although the presence of a valine/isoleucine at position 11 is statistically associated with a lower probability to progress to disease.

Correlation between HIV sequence evolution, specific immune response and clinical outcome in vertically infected infants

OBJECTIVE

To evaluate sequence evolution in relation to different rates of disease progression in infants infected with HIV-1.

DESIGN

Variability in the gp120 V3 region was analysed in HIV-1-infected children with different clinical courses, slow progression (n = 2) versus progressive disease (n = 3).

METHODS

Cloning and sequencing of virus-derived DNA from uncultured peripheral blood mononuclear cells was performed at two to three timepoints from birth and up to the fifth year of life. Sequence variability was estimated by calculating the genetic distance and the proportion and ratio of synonymous and non-synonymous nucleotide substitutions over time.

RESULTS

Genetic distances were significantly shorter in children with fast progression to disease, a predominance of synonymous nucleotide substitutions also being detected at later timepoints. Conversely, a preferential accumulation of non-synonymous nucleotide substitutions was apparent in children with slow disease progression. Furthermore, a positive correlation between a decreased ratio of synonymous/non-synonymous nucleotide substitutions and the ability of children's sera to react with synthetic peptides representing the autologous virus sequence was determined.

CONCLUSION

Data suggest that an antigenically more diverse virus population emerges in infected children with slower progression to disease as a result of a stronger immune pressure.

Effects of tamoxifen on GH and IGF-I levels in acromegaly

Tamoxifen (TAM), a non steroid partially competitive antagonist to the estrogen receptors, has been reported to decrease plasma GH and IGF-I levels both in vitro and in vivo. These data prompted us to evaluate GH and IGF-I changes in acromegaly after acute and chronic TAM administration. Nineteen acromegalic patients (6 M, 13 F, aged 30-70 years) were studied in a prospective open study. Acute TAM test (20 mg po) did not induce any significant change in GH and IGF-I levels. Chronic TAM treatment (20 mg/day for a month and 40 mg/day for another month) induced a transient increase in GH levels (from 9 [3-139] micrograms/l [median, range] to 12 [3-188] micrograms/l, p = 0.0025) and a persistent decrease in IGF-I levels (from 785 [500-1200] micrograms/l to 553 [209-1420] micrograms/l, p = 0.0034). Individual IGF-I values decreased in 13 patients and reached the normal range in 4 of them. At TAM withdrawal hormonal levels increased up to pretreatment values. There was no correlation between GH and IGF-I changes and results were not influenced by age, sex or gonadal status. In this setting it is likely that the observed decrease in plasma IGF-I levels is dependent on TAM activity at the hepatic level.

Role of immunity in maternal-infant HIV-1 transmission

Factors influencing human immunodeficiency virus type 1 (HIV-1) mother-to-child transmission include both immunological and virological parameters: higher viral loads have been associated with clinical stage of HIV-1-infected individuals as well as higher risk of mother-to-child transmission. Furthermore, we have shown that transmitting mothers more frequently harbour HIV-1 isolates with rapid/high syncytium-inducing (SI) biological phenotype than non-transmitting mothers do. Genetically homogeneous virus populations have been found in HIV-1-infected children at birth, in contrast to the heterogeneous virus populations often found in their infected mothers. This observation suggests that a few virus variants are transmitted or initially are replicating in the child. By comparing the HIV-1 gp120 V3 region of sequentially obtained samples from infected children with samples obtained from their mothers at delivery we found, however, that multiple variants of HIV-1 with different outgrowth kinetics can be transmitted. In addition, we have obtained results indicating an impaired ability of the immune response to adapt to the sequence evolution of HIV-1 in transmitting mothers, as assessed by measuring serum reactivities to peptides representing selected yet closely related V3 sequences. By analysing the presence of antibodies in maternal serum at delivery, which neutralize autologous isolates as well as other primary virus isolates, we have indications that a protective immunity in HIV-1 mother-to-child transmission might exist. Immunotherapy has been assessed in infected adult individuals by passive immunization with a variety of HIV-1-specific antibody products. Data from these studies indicated a differential response to therapy according to the stage of the disease. Active vaccine strategies, including envelope glycoproteins, pursued so far in seronegative adult subjects have shown limitations because broadly neutralizing antibodies, such as can be found in infected individuals, have not been evoked. Further investigations are therefore needed to give support for the potential use of either passive and/or active immunization for the prevention of HIV-1 mother-to-child transmission.

Are the SSTR alleles stable enough to be considered monophyletic and hence reliable anthropogenetic markers? Linkage disequilibrium study on the (ACT)n COL1A2 SSTR

An extremely low production rate of a polymorphic allele (formally called the mutation rate)--a prerequisite for using the allele as a marker (particularly for anthropogenetic purposes where the alleles must be assumed to be monophyletic)--cannot be taken for granted for alleles of highly polymorphic VNTRs, but a low production rate can be used to identify alleles produced by a single nucleotide substitution. This property was indirectly tested for the (ACT)n COL1A2 (of type I collagen) microsatellite SSTR (degree of heterozygosity H = 0.72) by searching for linkage disequilibria between the SSTR's four common alleles (n = 6, 8, 9, or 10) and three RFLPs of the same gene. A strong linkage disequilibrium between at least three of the four SSTR alleles and two of the three closely linked RFLPs has been demonstrated in a Sardinian population (Italy), a finding that suggests a low production rate of these alleles. Thus it seems that this highly polymorphic system and, by a reasonable extrapolation, other VNTRs with a comparable degree of heterozygosity may be valuable anthropogenetic markers, at least in distinguishing subgroups of a major ethnic group.

Persistence of somatostatinergic tone in acromegaly

It is a matter of debate whether hypothalamic somatostatin (SRIH) secretion in acromegaly is preserved and still regulated by the physiological feedback mechanisms of growth hormone (GH) and insulin-like growth factor I. To gather further information on this, the reproducibility of plasma GH changes induced by growth hormone-releasing hormone (GHRH) administration was evaluated in 15 acromegalic patients. There was a highly significant correlation between the peak/basal ratio (P/B) GH response in the 15 patients administered GHRH on two separate occasions (r = 0.99, p < 0.001). The test was performed also before and after the administration of drugs able to inhibit or stimulate hypothalamic SRIH release, by activating (pyridostigmine) or inhibiting (pirenzepine) cholinergic pathways, respectively. The GHRH-induced GH response (P/B = 2, range 1.1-26.1) was increased significantly by pyridostigmine pretreatment in 30 patients (P/B = 2.6, range 1.3-34.8; p = 0.0045). In nine out of 30 patients an increase of greater than 2 SD of within-subject GHRH variability was observed in response to GHRH plus pyridostigmine when compared to GHRH alone. An inverse correlation (r = -0.37, p < 0.05) was observed between GH response to GHRH alone and after pyridostigmine pretreatment. On the contrary, no change of GHRH-induced GH response was observed in 12 patients after pirenzepine pretreatment (P/B = 1.9, range 1.1-5 and P/B = 2, range 1.3-6 without and after pirenzepine pretreatment, respectively). These data suggest that in acromegaly the somatostatinergic tone does not seem to fluctuate, and that it can be inhibited often by cholinergic pathway activation but not increased further by cholinergic suppression.