Five waves of COVID-19 pandemic in Italy: results of a national survey evaluating the impact on activities related to arrhythmias, pacing, and electrophysiology promoted by AIAC (Italian Association of Arrhythmology and Cardiac Pacing)

BACKGROUND

The subsequent waves of the COVID-19 pandemic in Italy had a major impact on cardiac care.

METHODS

A survey to evaluate the dynamic changes in arrhythmia care during the first five waves of COVID-19 in Italy (first: March-May 2020; second: October 2020-January 2021; third: February-May 2021; fourth: June-October 2021; fifth: November 2021-February 2022) was launched.

RESULTS

A total of 127 physicians from arrhythmia centers (34% of Italian centers) took part in the survey. As compared to 2019, a reduction in 40% of elective pacemaker (PM), defibrillators (ICD), and cardiac resynchronization devices (CRT) implantations, with a 70% reduction for ablations, was reported during the first wave, with a progressive and gradual return to pre-pandemic volumes, generally during the third-fourth waves, slower for ablations. For emergency procedures (PM, ICD, CRT, and ablations), recovery from the initial 10% decline occurred in most cases during the second wave, with some variability. However, acute care for atrial fibrillation, electrical cardioversions, and evaluations for syncope showed a prolonged reduction of activity. The number of patients with devices which started remote monitoring increased by 40% during the first wave, but then the adoption of remote monitoring declined.

CONCLUSIONS

The dramatic and profound derangement in arrhythmia management that characterized the first wave of the COVID-19 pandemic was followed by a progressive return to the volume of activities of the pre-pandemic periods, even if with different temporal dynamics and some heterogeneity. Remote monitoring was largely implemented during the first wave, but full implementation is needed.

Inhaler mishandling remains common in real life and is associated with reduced disease control

Proper inhaler technique is crucial for effective management of asthma and COPD. This multicentre, cross-sectional, observational study investigates the prevalence of inhaler mishandling in a large population of experienced patients referring to chest clinics; to analyze the variables associated with misuse and the relationship between inhaler handling and health-care resources use and disease control. We enrolled 1664 adult subjects (mean age 62 years) affected mostly by COPD (52%) and asthma (42%). Respectively, 843 and 1113 patients were using MDIs and DPIs at home; of the latter, the users of Aerolizer®, Diskus®, HandiHaler® and Turbuhaler® were 82, 467, 505 and 361. We have a total of 2288 records of inhaler technique. Critical mistakes were widely distributed among users of all the inhalers, ranging from 12% for MDIs, 35% for Diskus® and HandiHaler® and 44% for Turbuhaler®. Independently of the inhaler, we found the strongest association between inhaler misuse and older age (p = 0.008), lower schooling (p = 0.001) and lack of instruction received for inhaler technique by health caregivers (p < 0.001). Inhaler misuse was associated with increased risk of hospitalization (p = 0.001), emergency room visits (p < 0.001), courses of oral steroids (p < 0.001) and antimicrobials (p < 0.001) and poor disease control evaluated as an ACT score for the asthmatics (p < 0.0001) and the whole population (p < 0.0001). We conclude that inhaler mishandling continues to be common in experienced outpatients referring to chest clinics and associated with increased unscheduled health-care resource use and poor clinical control. Instruction by health caregivers is the only modifiable factor useful for reducing inhaler mishandling.

Smoking cessation in patients requiring bronchoscopy: the Bronchoscopy AntiSmoking Study (BASIS)

We investigated the readiness to quit and the smoking cessation rates of smokers requiring bronchoscopy and receiving advice quitting. This randomized controlled trial evaluated the effectiveness of two smoking cessation interventions, either a brief advice (control group), or a longer support, delivered at the time of bronchoscopy. We consecutively enrolled 233 adult smokers, regardless of the initial level of motivation to quit. Their mean (SD) age was 57 (12) years; males were 192. They had smoked a median of 44.5 pack-years. Their mean (SD) Fagerstrom score was 8 (2). There was no difference between groups. Surprisingly, 45% of participants were in the action stage at baseline; these 105 subjects had quit in the week immediately prior to the bronchoscopy. At 6- and 12-months follow-up visits, respectively 41% and 29% of participants in the intervention group and 27% and 13% in the control group objectively showed a 1-week point prevalence abstinence. The difference was significant at 6 months (p<0.05) but not at 1-year visit (p=0.052), even if there was a trend towards greater cessation rate in the intervention group. In multivariable logistic models, at the final visit being a quitter was positively associated with having been in the action stage at baseline and negatively with the Fagerstrom score and the presence of smokers in household. We conclude that the time of bronchoscopy may possibly predispose smokers to quit. Further efforts are needed to clear whether more protracted support might achieve higher long-term smoking cessation rates.

CD38 expression enhances sensitivity of lymphoma T and B cell lines to biochemical and receptor-mediated apoptosis

CD38 has been widely characterised both as an ectoenzyme and as a receptor. In the present paper, we investigated the role of CD38 as possible modulator of apoptosis. CD38-positive (CD38(+)) and negative (CD38(-)) fractions, obtained by sorting CD38(+) cells from lymphoma T (Jurkat) and lymphoma B (Raji) and by transfecting lymphoma LG14 and myeloid leukemia K562 cell lines, were used. Cellular subpopulations were exposed to different triggers (H(2)O(2), UV-B, alpha-TOS and hrTRAIL) and the extent of apoptosis was determined by Annexin V-FITC/PI assay. Our data showed that, in lymphoma cells, propensity to apoptosis was significantly linked to CD38 expression and that, remarkably, such response was independent of the nature of the trigger used. Inhibition of CD38 expression by antisense oligonucleotides treatment resulted in CD38-silenced fractions which were as prone to apoptosis as CD38(-) ones. Notably, susceptibility of K562 to apoptosis-inducing challenges was not affected by CD38 expression.

Long-term oxygen therapy in chronic respiratory failure: A Multicenter Italian Study on Oxygen Therapy Adherence (MISOTA)

BACKGROUND

The adherence to the prescribed oxygen therapy is difficult to obtain for patients on long-term oxygen therapy (LTOT). There is little information on the modalities of oxygen utilisation for patients on LTOT who are using liquid oxygen in real life.

STUDY OBJECTIVE

Evaluation of the behaviour and the knowledge regarding LTOT in a large group of patients mainly using liquid oxygen.

DESIGN AND SETTING

Questionnaire administered to consecutive outpatients on domiciliary LTOT for at least 6 months referring to one of 20 clinics throughout Italy. Blinded to this result, the physician who cared for the patient completed another questionnaire.

RESULTS

We evaluated 1504 patients (mean age 71.6 years; males 64%; 74% suffering from COPD). Most respondents (93%) used liquid oxygen with mobile device. Fifteen per cent of patients had a prescribed length of oxygen therapy less than 15 h/day; 21% reported to practice oxygen for less than 15 h/day. Patients reported using oxygen for less hours than had been prescribed during the day at rest (P=0.02, k=0.80) during exercise (P=0.002, k=0.72) and at night (P=0.0036, k=0.77). There was no difference between the flow prescribed by the physician and that known and practised by the patient at rest or during sleep; during exercise the flow reported by patients was lower than that prescribed by the physician. Patients used in the night but not at rest or during exercise, a lower level of oxygen flow than what they knew had been prescribed. Fifty-five per cent of patients received indications to modify the oxygen flow in the various situations of life. Liquid oxygen was almost always useful to decrease breathlessness. Most (84%) patients possessed a mobile device, but only 40% declared they used it daily, 'shame' being indicated as the principal barrier. On the physicians' side, we found that the criteria used in prescribing did not always correspond to evidence-based recommendations.

CONCLUSION

The widespread use of liquid oxygen did not automatically assure optimal adherence to the prescribed treatment as regards times and modality of oxygen use. A better education of patients, relatives, and the general public, as well as increased self-assessment on the part of health caregivers would improve the practice of LTOT in Italy.

Inhalation technique and variables associated with misuse of conventional metered-dose inhalers and newer dry powder inhalers in experienced adults

BACKGROUND

Pressurized metered-dose inhalers (pMDIs) are often poorly used, but little information is available concerning use of the newer dry powder inhalers (DPIs).

OBJECTIVE

To estimate the inhalation technique and variables associated with the misuse of pMDIs and newer DPIs in clinical practice.

METHODS

A multicenter, observational survey was used to evaluate the inhalation technique in 1,404 experienced outpatients aged 15 to 88 years affected mostly by asthma (47%) and chronic obstructive pulmonary disease (39%). A total of 1,056 patients were using pMDIs, 190 in conjunction with a large volume spacer (LVS); regarding DPIs, 230 patients were using the Aerolizer Inhaler, 524 were using the Turbuhaler, and 475 were using the Diskus. In each center, a trained observer recorded patients' inhalation techniques for each inhaler used against a standardized step-by-step checklist.

RESULTS

Twenty-four percent and 3% of patients used pMDIs poorly, alone or with an add-on LVS, respectively. Failure to correctly perform essential steps for reliable lung delivery with the Aerolizer Inhaler, Turbuhaler, and Diskus was found in 17%, 23%, and 24% of patients, respectively. There was no difference in most variables correlated with poor inhalation between patients using pMDIs and those using DPIs.

CONCLUSIONS

The use of DPIs is associated with a similar percentage of inadequate inhalation technique as the use of pMDIs in clinical practice. The addition of an LVS to a pMDI and education from health care personnel, rather than simply changing inhalers, represent the best strategies for minimizing poor inhalation technique.

How does a normal human cell become a cancer cell?

The mechanism by which cells become cancerous has been studied in several different species and cell types. Here, we will focus on the mechanism by which a normal human cell becomes a cancer cell and specifically discuss genes that researchers have used to transform cells. Studying how those genes affect cellular immortalization and transformation will help researchers understand more about cancer biology, find new treatments for cancer and/or improve cell survival during gene therapy.

Ras family genes: an interesting link between cell cycle and cancer

Ras genes are evolutionary conserved and codify for a monomeric G protein binding GTP (active form) or GDP (inactive form). The ras genes are ubiquitously expressed although mRNA analysis suggests different level expression in tissue. Mutations in each ras gene frequently were found in different tumors, suggesting their involvement in the development of specific neoplasia. These mutations lead to a constitutive active and potentially oncogenic protein that could cause a deregulation of cell cycle. Ras protein moderates cellular responses at several mitogens and/or differentiation factors and at external stimuli. These stimuli activate a series of signal transduction pathways that either can be independent or interconnected at different points. Recent observations begin to clarify the complex relationship between Ras activation, apoptosis, and cellular proliferation. A greater understanding of these processes would help to identify the factors directly responsible for cell cycle deregulation in several tumors, moreover it would help the design of specific therapeutic strategies, for the control on the proliferation of neoplastic cells. We summarize here current knowledge of ras genes family: structural and functional characteristics of Ras proteins and their links with cell cycle and cancer.

Ras family genes: an interesting link between cell cycle and cancer

Ras genes are evolutionary conserved and codify for a monomeric G protein binding GTP (active form) or GDP (inactive form). The ras genes are ubiquitously expressed although mRNA analysis suggests different level expression in tissue. Mutations in each ras gene frequently were found in different tumors, suggesting their involvement in the development of specific neoplasia. These mutations lead to a constitutive active and potentially oncogenic protein that could cause a deregulation of cell cycle. Ras protein moderates cellular responses at several mitogens and/or differentiation factors and at external stimuli. These stimuli activate a series of signal transduction pathways that either can be independent or interconnected at different points. Recent observations begin to clarify the complex relationship between Ras activation, apoptosis, and cellular proliferation. A greater understanding of these processes would help to identify the factors directly responsible for cell cycle deregulation in several tumors, moreover it would help the design of specific therapeutic strategies, for the control on the proliferation of neoplastic cells. We summarize here current knowledge of ras genes family: structural and functional characteristics of Ras proteins and their links with cell cycle and cancer.

Rapid and sensitive detection of recombinant soluble proteins in the supernatant of transfected mammalian cells

Cloning and expression of recombinant soluble proteins could be quite a difficult task, especially when it comes to reliably detect minute amounts of the soluble protein in the supernatant of transfected mammalian cells. Timing and sensitivity are of the essence in order to optimise the benefits/costs balance and to decide which clones to grow further and which ones to discard. Here we propose a modified inhibition assay. The key feature of this approach is the development of a sensitive and quantitative test to detect the presence of the recombinant soluble protein by exploiting its ability to compete with the binding of a specific monoclonal antibody to a target cell. The described procedure is a sensitive, efficient, dependable and low cost method.

GENebu Project: home nebulizer use and maintenance in Italy

Due to the lack of information on this topic, the Educational Group of the Italian Association of Hospital Pneumologists performed an open, multicentre, observational survey to evaluate home nebulizer practices in Italy. From May-December 1999, all patients attending one of the 27 participating chest clinics throughout Italy and who were or had been using a home nebulizer in the previous 6 months were consecutively enrolled. All patients completed a self-administered questionnaire on their current practices of home nebulization. Of the 1,721 questionnaires delivered, 1,257 were returned with an overall response rate of 73%. Most patients (82.8%) reported using their nebulizer for bronchopulmonary symptoms and the remaining patients only used theirs for upper respiratory tract diseases. Subjects using their nebulizer for lower respiratory symptoms were older (p<0.001), predominantly female (p<0.001) and used their nebulizer more frequently (p<0.001). Forty per cent of patients >60 yrs old used their nebulizer regularly, at least once a day. More than 60% of respondents never received any information from healthcare workers on the correct usage of their nebulizer, and >75% received no information on nebulizer hygiene and care. Patients who received information on the use and maintenance of their nebulizer from caregivers more commonly attended to these practices (p<0.01). The present survey suggests that home nebulizer use and maintenance in Italy are heterogeneous, and there is the need to implement better nebulizer practice.

pRb2/p130 and p107 control cell growth by multiple strategies and in association with different compartments within the nucleus

It has been recently reported that retinoblastoma family proteins suppress cell growth by regulating not only E2F-dependent mRNA transcription but also rRNA and tRNA transcription and, through HDAC1 recruitment, chromatin packaging. In the present study we report data showing that these various control strategies are correlated, at least in part, with nuclear compartmentalization of retinoblastoma proteins. In a first series of experiments, we showed that pRb2/p130 and p107 are not evenly distributed within the nucleus and that cell cycle-dependent binding with E2F4 changes also as a function of their subnuclear localization. Namely, in the nucleoplasm pRb2/p130-E2F4 complexes are more numerous during G0/G1 while in the nucleolus they increase in S phase. Partially different functions for p107 are suggested since p107-E2F4 complexes in the nucleoplasm are more numerous is S phase with respect to G0/G1 and no cell cycle change is observed in the nucleolus. In a second series of experiments we showed that pRb2/p130, p107, E2F4, and pRb2/p130-HDAC1 complexes are all inner nuclear matrix-associated proteins and localize to sites different from pRb/p105 ones. We provide further evidence of multiple and partially distinct retinoblastoma protein family functional roles during cell cycle. Moreover, our data support emerging evidence for functional interrelationships between nuclear structure and gene expression.

Ultrastructural organization of the sperm nuclear matrix

The organization of DNA-protamine complexes and their association with the nuclear matrix have been analyzed in sperm nuclei by in situ Nick Translation at the electron microscope. The data obtained indicate that the chromatin organization in sperm nuclei is maintained during the sperm condensation by means of interaction with the nuclear matrix at fixed sites. The fine structure of the sperm nucleus and sperm nuclear matrix, investigated by sectioning and replica of freeze-fractured specimens, suggests that the lamellar array observed by freeze-fracturing in the sperm nuclei, could depend on the inner matrix which presents a regular organization of globular structures involved in the maintenance of chromatin domains.

Application of the primer in situ DNA synthesis (PRINS) technique to titer recombinant virus and evaluation of the efficiency of viral transduction

Titration is an important and critical step in dosing recombinant virus for gene therapy. We present a relatively fast, convenient, and sensitive method that allows for precise quantification of recombinant retrovirus. The method is based on PCR amplification of a foreign gene by the PRINS (primer in situ DNA synthesis) technique. The PRINS technique is based on the sequence-specific annealing of unlabeled oligonucleotide DNA in situ. This oligonucleotide operates as a primer for in situ chain elongation catalyzed by the Taq I polymerase. Using digoxygenin-labeled nucleotides as a substrate for chain elongation, the neo-synthetic DNA is labeled by an FITC-conjugated anti-digoxygenin antibody. To avoid the possibility of false positives, we amplified the puromycin-resistance gene, which is associated with the transgene in the same viral vector and is not normally present in mammalian cells. The retroviral titer was evaluated by counting fluorescein isothiocyanate-positive cells after PRINS labeling, while knowing the number of plated cells that were transduced with different amounts of viral supernatant. A comparable viral concentration of 1 x 10(7) infectious units/mL was found among the retroviruses.

Expression of cell-cycle-associated proteins pRB2/p130 and p27kip in vulvar squamous cell carcinomas

Squamous cell vulvar carcinoma accounts for 4% of all gynecologic malignancies. The cause of vulvar cancer is still unclear. Identification of new biologic factors involved in vulvar carcinogenesis may be useful in clarifying the natural history of this malignancy. We investigated the immunohistochemical expression of the retinoblastoma-related proteins pRB2/p130 and CKI p27kip1 in a series of 51 invasive squamous cell carcinomas of the vulva (ISCCs) and in synchronous normal vulvar skin, non-neoplastic epithelial disorders (NNED) and vulvar intraepithelial neoplasia (VIN). Normal vulvar skin staining showed positivity for both pRB2/p130 and p27kip1. Loss of pRB2/p130 occurred in 29 (57%) of 51 specimens of ISCCs, and in 1 of 7 specimens with VIN (14%; P = .04). We also observed a significant decrease of pRB2/p130 expression from NNED to neoplastic tissues (VIN and ISCCs) (P = .004). Loss of p27kip1 expression was found in 16 of 51 specimens (31%) of invasive carcinomas, in 1 (14%) of 7 specimens of VIN, and in 2 of 18 specimens of NNED (11%). pRB2/p130 and p27(kip1) did not correlate significantly with any of the clinicopathologic parameters examined. Our data indicate that loss of pRB2/p130 and p27kip1 are frequent events in invasive vulvar carcinomas compared with synchronous premalignant lesions, non-neoplastic epithelial disorders, and normal vulvar skin. The significant progressive decrease of pRB2/p130 expression from non-neoplastic epithelial alterations through intraepithelial neoplasia to invasive vulvar carcinomas suggests a role for this tumor suppressor gene in vulvar carcinogenesis.

Biochemical changes in transplanted rat liver stored in University of Wisconsin and Euro-Collins solutions

BACKGROUND

Liver ischemia/reperfusion injury is a severe problem in transplantation, and preservation solutions could be critical for liver viability. The aim of our study was to evaluate the cytosolic and mitochondrial glutathione levels, the glyoxalase II activity, and the mitochondrial hydroperoxide contents of livers stored in different preservation solutions for 7 or 24 h and after transplantation.

MATERIALS AND METHODS

Orthotopic liver transplantation was performed without reconstruction of the hepatic artery. The livers were stored at 4 degrees C for 7 or 24 h in University of Wisconsin or Euro-Collins solutions. Portions of livers before and after transplantation were homogenized and mitochondria isolated.

RESULTS

Cytosolic glutathione levels were decreased in all stored livers and after transplantation. In livers stored with University of Wisconsin solution, mitochondrial glutathione was unchanged during cold storage and no significant decrease has been found after reperfusion, whereas in livers stored in Euro-Collins solution, mitochondrial glutathione was decreased and a further significant decrease was found 30 min after reperfusion. Mitochondrial hydroperoxides were higher in livers stored in Euro-Collins solution than in University of Wisconsin solution after 30 min of reperfusion. Mitochondrial glyoxalase II did not show any change by reperfusion.

CONCLUSION

We have demonstrated that rat liver stored in Euro-Collins solution suffered a severe depletion of mitochondrial GSH and a concomitant increase of hydroperoxides. The data obtained suggested that the livers stored with University of Wisconsin solution were probably less prone to ischemia/reperfusion injury after liver transplantation.

A serine 37 mutation associated with two missense mutations at highly conserved regions of p53 affect pro-apoptotic genes expression in a T-lymphoblastoid drug resistant cell line

The p53 protein accumulates rapidly through post-transcriptional mechanisms following cellular exposure to DNA damaging agents and is also activated as a transcription factor leading to growth arrest or apoptosis. Phosphorylation of p53 occurs after DNA damage thereby modulating its activity and impeding the interaction of p53 with its negative regulator oncogene Mdm2. The serines 15 and 37 present in the amino terminal region of p53 are phosphorylated by the DNA-dependent protein kinase (DNA-PK) in response to DNA damage. In order to verify if specific p53 mutations occur in the multi-drug resistance phenotype, we analysed the p53 gene in two T-lymphoblastoid cell lines, CCRF-CEM and its multi-drug-resistant clone CCRF-CEM VLB100, selected for resistance to vinblastine sulfate and cross-resistant to other cytotoxic drugs. Both cell lines showed two heterozygous mutations in the DNA binding domain at codons 175 and 248. The multi-drug resistant cell line, CCRF-CEM VLB100, showed an additional mutation that involves the serine 37 whose phosphorylation is important to modulate the protein activity in response to DNA damage. The effects of these mutations on p53 transactivation capacity were evaluated. The activity of p53 on pro-apoptotic genes expression in response to DNA damage induced by (-irradiation, was affected in the vinblastine (VLB) resistant cell line but not in CCRF-CEM sensitive cell line resulting in a much reduced apoptotic cell death of the multi-drug resistant cells.

Perception of methacholine-induced airway obstruction in asthmatics

The main objective of this study was to examine the perception of the first symptom during methacholine bronchoconstriction as soon as it occurred, and in the second instance to quantify the intensity of the breathlessness by means of the Borg Scale performed at the end of challenge so to not determine any difficulties for identification of the first symptom. A methacholine challenge test was carried out in 139 symptom-free asthmatics with a normal pulmonary function. When the first symptom was reported by the subject, the forced expiratory volume in one second (FEV1) was measured immediately. FEV1 was expressed as a percentage of the best personal value (FEV1%BPV). The intensity of the breathlessness was rated using a modified Borg Scale at the end of the challenge test so as not to confuse the patient. Seven subjects felt nothing during challenge. The first symptoms varied: constriction behind the breastbone (49%), inspiratory shortness (16.5%), coughing (10%), wheezing, throat constriction, general chest tightness, pain behind the sternum, and a sensation of rheum behind the sternum. FEV1%BPV at the first symptom was 80.5 +/- 10 (range 41-99). No symptom was perceived by 42% of the subjects within the 80-100 range of FEV1%BPV. FEV1%BPV at the first symptom was related to the log of the provocative dose causing a 20% fall in FEV1 (r = 0.2, p < 0.05). An inverse correlation between Borg Score and final FEV1%BPV (r = -0.25, p < 0.01) was found at the end of challenge. A subgroup of 39 subjects with similar final FEV1%BPV values (68-72) showed a correlation between the Borg Score at end of challenge and FEV1%BPV at the first symptom (r = 0.59, p < 0.001). The first symptom of the methacholine-induced bronchoconstriction varies in asthmatics and may be atypical, the bronchoconstriction level at which it is felt also varies among individuals, highly methacholine-responsive subjects perceive the bronchoconstriction later, while late perceivers of the first symptom show less intense breathlessness at the end of challenge. The measurement of the patient's ability to perceive asthmatic symptoms during the methacholine challenge test could be used to single out poor perceivers.

Monoclonal antibodies and therapy of human cancers

This survey is an overview of the applications of murine, humanized and recombinant monoclonal antibodies for in vivo diagnostic and therapeutic applications. Monoclonal antibodies (mAb) have been applied to the diagnosis and therapy of an array of human diseases. The initial failures of early clinical trials have been overcome through the production of a new generation of mAb which features reduced immunogenicity and improved targeting abilities. The early models of mAb therapy were focused on enhancing the cytolytic mechanisms against the tumor cells. More recently, successful mAb-based therapies were targeted to molecules involved in the regulation of growth of cancer cells. This has highlighted the relevance of understanding receptor-mediated signaling events, and may provide new opportunities for anti-tumor antibody targeting. Despite all the difficulties, clinical data is outlining an increasingly significant role for antibody-mediated cancer therapy as a versatile and powerful instrument in cancer treatment. One reasonable expectation is that treatment at an earlier stage in the disease process or in minimal residual disease may be more advantageous.

Genetic alterations disrupting the nuclear localization of the retinoblastoma-related gene RB2/p130 in human tumor cell lines and primary tumors

The prototypic tumor suppressor gene, the retinoblastoma gene (RB/ p105), is mutated in a variety of human tumors. However, to date, mutational data on retinoblastoma family members p107 and RB2/p130 in tumors is lacking. We studied the expression of pRb2/p130 by immunocytochemistry and Western blot analysis in a panel of human osteosarcoma and lymphoid cell lines. Only the lymphoid cell lines showed an abnormal cytoplasmic localization of pRb2/p130, suggesting possible alterations within the region of nuclear localization signaling. We screened these cell lines for genetic alterations of the RB2/p130 gene in the region of the putative bipartite nuclear localization signal (NLS). This region is highly homologous with that of the RB/p105 gene. In addition, we screened four primary Burkitt's lymphomas for genetic alterations in the RB2/p130 gene. Naturally occurring mutations, which disrupt the putative bipartite NLS, were found in lymphoma cell lines and primary tumors, but not in the osteosarcoma cell lines, where normal nuclear localization of the protein was detectable. Site-directed mutagenesis and transfection assay using NLS mutants displayed markedly reduced biological activity as measured by flow cytometric analysis. This study clearly describes RB2/ p130 as an important target for mutations and subsequent inactivation in lymphoma pathogenesis, thus validating that RB2/p130 is a classical tumor suppressor gene.

Mutations in the retinoblastoma-related gene RB2/p130 in lung tumors and suppression of tumor growth in vivo by retrovirus-mediated gene transfer

The retinoblastoma (Rb) family consists of the tumor suppressor pRb/p105 and related proteins p107 and pRb2/p130. Recent immunohistochemical studies of the retinoblastoma family of proteins in 235 specimens of lung cancer show the tightest inverse association between the histological grading in the most aggressive tumor types and pRb2/p130. This led us to study a panel of human lung cancers for mutations in the RB2/p130 gene. Mutations in the Rb-related gene RB2/p130 were detected in 11 of 14 (78.5%) primary lung tumors by single-strand conformation polymorphism and sequence analysis. A Moloney leukemia virus-based retroviral system was set up, and a comparable viral concentration of 1 x 10(7) infectious units/ml was obtained. Retrovirus-mediated delivery of wild-type RB2/p130 to the lung tumor cell line H23 potently inhibited tumorigenesis in vitro and in vivo, as shown by the dramatic growth arrest observed in a colony assay and the suppression of anchorage-independent growth potential and tumor formation in nude mice. The tumors transduced with the RB2/p130 retrovirus diminished in size after a single injection, and a 12-fold reduction in tumor growth after RB2/p130 transduction compared with the Pac-transduced tumors (92% reduction, P = 0.003) and lacZ-transduced tumors (93% reduction, P < 0.001) was found to be statistically significant. These findings provide the missing confirmation that RB2/p130 is a "bona fide" tumor suppressor gene and strengthen the hypothesis that it may be a candidate for cancer gene therapy for lung cancer.

Mutations in the retinoblastoma-related gene RB2/p130 in primary nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an endemic cancer in southern China and northern Africa, and its pathogenesis is not yet well defined at the molecular level. Although the involvement of p53 and of the retinoblastoma gene (RB/p105) in NPC has been well studied, there is paucity of mutational data regarding the retinoblastoma-related gene RB2/p130 in primary tumors and particularly in NPC. We have shown previously that RB2/p130 could be rearranged in a nasopharyngeal cell line. In the present study, we screened by single-strand conformation polymorphism and sequence analysis the retinoblastoma-related gene RB2/p130 for mutations within exons 19-22. Mutations in the RB2/p130 gene were detected in 3 of 10 primary human NPCs from Northern Africa (30%). These findings, along with previous data showing that genetic replacement of RB2/p130 restores a normal growth pathway in the nasopharyngeal cell line Hone-1, strengthen the hypothesis that genetic changes of RB2/p130 may be involved in the development and/or progression of nasopharyngeal cancer and suggest that RB2/p130 could be considered a tumor suppressor gene and may be a candidate for novel gene therapeutic approaches for NPC.

Retinoblastoma-related p107 and pRb2/p130 proteins in malignant lymphomas: distinct mechanisms of cell growth control

pRb/p105, p107, and pRb2/p130 compose the retinoblastoma (RB) family of proteins and regulate cellular growth and differentiation. Because recent functional studies have indicated that the expression of the RB-related proteins p107 and pRb2/p130 are tightly cell cycle regulated, we were interested in investigating their expression along with cellular kinetic characteristics and proliferative features of non-Hodgkin's lymphomas (NHLs). p107 and pRb2/ p130 expression was determined immunohistochemically in biopsy specimens from 83 untreated patients with NHLs of various histiotypes. The expression of these two RB-related proteins was correlated with the mitotic index, apoptotic index, and percentages of Ki-67(+), cyclin A(+), p34(+), and cyclin B(+) cells. The overall survival rate was evaluated according to the Kaplan-Meier method and the log-rank test. We found a positive correlation between the percentages of cells positive for p107 and proliferative features such as mitotic index and percentage of Ki-67(+) and cyclin A(+) cells, whereas such correlation could not be demonstrated for the percentages of pRb2/p130 positive cells. Low immunohistochemical levels of pRb2/p130 detected in untreated patients with NHLs of various histiotypes inversely correlated with a large fraction of cells expressing high levels of p107 and proliferation-associated proteins. Such a pattern of protein expression is normally observed in continuously cycling cells. Interestingly, such cases showed the highest survival percentage (82.5%) after the observation period of 10 years. Thus, down-regulation of the RB-related pRb2/p130 protein could be one of the reasons why these cases display such a high rate of proliferation and why they respond so well to therapy.

Pulmonary function abnormalities in children with Henoch-Schönlein purpura

Henoch-Schönlein purpura (HSP) is a widespread necrotizing vasculitis affecting small vessels characterized by nonthrombocytopenic purpura. Pulmonary involvement is a rare fatal complication with diffuse alveolar haemorrhage. The objective of this study was to evaluate possible early lung function abnormalities and to establish any relationship with the clinical activity of the disease. Fifteen children with HSP and without clinical or radiological evidence of lung involvement underwent pulmonary function study at the onset of the disease. A sample of 28 subjects matched by age, height, and weight was chosen as a control group. After a mean of 21 months (range 12-43) lung function tests were repeated in 10 of the previously studied children. During the acute phase of the disease the transfer factor for carbon monoxide, measured by steady-state (TL,COss) and single-breath (TL,COsb) methods, was found to be significantly lower in children with HSP than control subjects. There was no significant relationship between pulmonary function tests with symptoms and signs at onset, nor was there any correlation between variables and serum immunoglobulin A (IgA) concentration. In all but two patients, clinical recovery was observed within 6 weeks from the onset of the disease. In one case relapses of purpuric skin lesions were observed during the first 3 months of follow-up. The second case had relapses of purpuric skin lesions and microscopical haematuria during the 12 months following the onset of the disease with characteristic IgA mesangial deposition on renal biopsy. Although the overall mean value of TL,COsb improved from baseline to the second investigation, in both patients the recurrences of clinical signs were associated with a slight impairment of TL,COsb at the second evaluation. These data suggest an early subclinical lung impairment in children with Henoch-Schönlein purpura during the active phase of the disease. The presence of isolated pulmonary function abnormalities was not associated with the subsequent development of lung disease.

Apoptotic pathways depend on the target enzymatic activity and not on the triggering agent

Molt-4 human leukemia cells were triggered to apoptosis by various agents with different mechanisms of action. Staurosporine, a protein kinase C (PKC) inhibitor; camptothecin, a topoisomerase I blocking drug; and tiazofurin, an inhibitor of inosine 5'-phosphate dehydrogenase (IMPDH), were used. Ultrastructural analysis showed morphologic changes characteristic of apoptosis that were very similar for all three agents. Nevertheless, DNA oligonucleosomic fragmentation was not detectable by agarose gel electrophoresis. However, a genomic DNA cleavage appeared after pulse-field gel electrophoresis (PFGE) in cells treated with these agents for 24 h. Furthermore, in situ nick translation (NT) showed a finely spotted nuclear labelling in staurosporine-treated cells and a compact fluorescence after camptothecin incubation. In tiazofurin-treated cells an intermediate pattern was found. Therefore, apoptotic agents with different mechanisms of action induced the formation of large genomic DNA fragments and very similar ultrastructural changes. Therefore, both phenomena and the closely related apoptosis progression depend on target cell machinery and not on the triggering agent.

Different approaches to the study of apoptosis

The morphological features of cell undergoing programmed cell death is well known and has been widely described in a number of experimental models with a variety of apoptotic triggering agents. Despite the similar cell behaviour, underlying molecular events seem variable and only partially understood. A multiple approach appears crucial to better clarify the phenomenon. The first technique, DNA gel electrophoresis, allows the identification of fragmented DNA and has been long considered the hallmark of apoptosis. Different patterns of DNA cleavage, which can be identified by conventional or "pulsed-field gel" electrophoresis, are presented and discussed. "In situ" labelling methods are also described both with terminal deoxynucleotidyl transferase and DNA polymerase I, aimed at the study of the distribution of DNA cleavage areas. Flow cytometry is also proposed and different technical approaches, based on different laser utilizations, are discussed. Ultrastructural analysis, allowing the study of apoptotic cell details, is finally considered.

Molecular abnormalities in leukemia: the 11q23 story so far

Various hematopoietic malignant disorders have been shown to bear chromosome abnormalities of the 11q23 band, which can be rearranged with many different chromosomal regions in a wide variety of different leukemia subtypes. Several laboratories have identified a trithorax-related gene that is involved in most of the 11q23 abnormalities. Although some patterns and associations between the partner genes are beginning to emerge, it is not yet possible to frame a single unifying hypothesis for 11q23 leukaemic transformation. The aim of this review is to summarise the recent data concerning these 11q23 rearrangements and the understanding of their consequences.

IMP dehydrogenase inhibitor, tiazofurin, induces apoptosis in K562 human erythroleukemia cells

Tiazofurin, an anticancer drug which inhibits IMP dehydrogenase, decreases cellular GTP concentration, induces differentiation and down-regulates ras and myc oncogene expression, caused apoptosis of K562 cells in a time- and dose-dependent fashion. Apoptotic cells were detected by (1) flow cytometry, (2) electron microscopy, and (3) fluorescence in situ nick translation and confocal microscopy, while the DNA ladder was not detectable. The induced apoptosis was abrogated by guanosine which replenishes GTP pools through the guanosine salvage pathways, while it was enhanced by hypoxanthine, a competitive inhibitor of GPRT. The tiazofurin-mediated apoptosis may therefore be linked with the decrease of GTP and the consequent impairment of specific signal transduction pathways. Tiazofurin induced apoptosis also in lymphoblastic MOLT-4 cells, suggesting that this action is not confined to cells of the myeloid lineage, where the differentiating effects of the drug are more pronounced.

Enhanced resolution of specific chromosome and nuclear regions by reflectance laser scanning confocal microscopy

DNA sequences digested by HaeIII and reconstructed by in situ nick translation employing digoxigenin-labelled nucleotides are usually revealed either by horseradish peroxidase or FITC fluorescence. To obtain a significant improvement in terms of resolution, sensitivity and specificity, colloidal gold has been used instead of FITC (as the reporter molecule) to reveal the labelled DNA. Colloidal gold and propidium iodide were visualised by employing the reflectance mode and the 488-nm laser line of a confocal laser scanning microscope. In chromosomes, the fluorescent reaction pattern showed diffuse areas of labelling in which it was impossible to identify any specific kind of banding along the arms. In some chromosomes and, in particular, 1 and 9, a C-negative banding due to the negativity of the centromeric areas was seen. A more accurate localisation on chromosomes, including telomeric regions, often organised in spot pairs that resembled an R-like banding, was detected using 1-nm colloidal gold. A fine labelling was also demonstrated in nuclei, especially at their peripheral heterochromatin. The non-fading properties of colloidal gold combined with visualisation by reflectance confocal laser scanning microscopy demonstrated the possibility of obtaining a higher spatial resolution than when using conventional fluorophores or higher laser wavelength. This improved way to study the localization of HaeIII digestion sites in single chromosomes and in interphase nuclei made the reaction a valuable tool for the detection of antigens or of specific DNA sequences in biological preparations.

Multiple fluorescence and reflectance simultaneous detection by confocal microscopy of HaeIII digested DNA sequences

Human metaphase chromosomes were isolated and digested in situ with HaeIII restriction enzyme to detect cytosine and guanine-rich sequences (CpG islands), which are known to be associated with most of the mammalian genes. Digested DNA was reconstructed by in situ nick translation employing digoxigenin-labeled nucleotides. The DNA sequences were revealed by antibodies conjugated either with fluorescein isothiocyanate or 1-nm colloidal gold. DNA was counterstained with propidium iodide. A sensitive, high resolution method for visualizing three signals, simultaneously excited by a single argon laser line of 488 nm has been developed. The green fluorescence of fluorescein isothiocyanate was detected in combination with the red fluorescence of propidium iodide, and the third signal was imaged by employing the reflectance mode of the confocal microscope after silver enhancement of the gold beads. The high reflectance intensity, the accurate localization and the non-fading properties of colloidal gold made the reaction a valuable tool for the detection of antigens and, as a consequence, of specific DNA sequences in chromosome preparations. Overlaying of three signals allowed the simultaneous observation of distinct structures: total DNA, as well as fluorescein- and gold-labeled sequences after in situ nick translation, or total DNA and centromeric sequences of two different chromosome pairs (17 and X) after in situ hybridization. The use of HaeIII restriction enzyme that cut CpG islands combined with in situ nick translation identified the chromosome sites where active, inactive or housekeeping genes can be located. In chromosomes, the fluorescent reaction pattern showed large areas of labeling, while a more defined staining, often organized in spot pairs that resembled an R-like banding, was detected when the reflected mode was used. These results are confirmed by the observation that R-like bands actually are multiple symmetrical spots localized on sister chromatids. In addition, some chromosomes, and in particular 1 and 9, displayed a C-negative banding due to the negativity of the centromeric areas. Reflectance confocal scanning microscopy and in situ nick translation represent a powerful tool to study the in situ genome organization.

Comparison of methods for the detection of in situ restriction enzyme – nick translation using fluorochromes and confocal microscopy

A series of experiments was carried out to determine the most efficient methods for detecting incorporated nucleotides in the "in situ" restriction enzyme – nick translation technique. Different methods were tested on fixed human metaphase chromosomes using confocal microscopy for the demonstration of the patterns produced. Of the various techniques tested, that using DIG-dUTP in conjunction with FITC-labelled anti-DIG appears to show the greatest sensitivity and specificity. The use of biotinylated nucleotides with FITC-avidin gives rather less sensitivity, while direct labelling with fluorescein-dUTP produces results more rapidly with better chromosome morphology but at the cost of reduced sensitivity. Resorufin-labelled dUTP was unusable, because of the low level of fluorescence and its very rapid fading. The successful fluorescence methods are more sensitive and faster than using horseradish peroxidase or alkaline phosphatase for detection.Key words: restriction enzymes, nick translation, chromosomes, fluorochromes, confocal microscopy.

Endothelin-1 in idiopathic pulmonary fibrosis

AIMS--To evaluate whether endothelin-1 is involved in the pathology of idiopathic pulmonary fibrosis (IPF). METHODS--Plasma endothelin-1 concentrations were evaluated in 37 patients with IPF and 27 normal controls by radioimmunoassay. In addition, expression of endothelin-1 in lung tissue was evaluated in biopsy specimens obtained from four patients with IPF. Three biopsy specimens of normal lung were used as controls. Endothelin-1 immunoreactivity was detected using immunohistochemistry. RESULTS--Elevated endothelin-1 plasma concentrations were found in patients with IPF compared with controls and a positive correlation was found with duration of disease. No significant difference was observed between treated and untreated patients with IPF. Increased endothelin-1 immunoreactivity was found in lungs of three of four patients with IPF. Endothelin-1 positive consisted mainly of small vessel endothelial cells. Some scattered macrophages were also positive. CONCLUSIONS--Elevated plasma concentrations and expression of endothelin-1 in lung tissue are suggestive of increased production of endothelin-1 in at least a proportion of patients with IPF. Consequently, endothelin-1 activity could play a role in the fibrogenic process of the disease.

Assessment of emphysema using high resolution CT, CT expiratory density mask, and plain chest films

Pulmonary function tests (diffusing capacity for carbon monoxide of the lungs) and radiological imaging (plain chest film, high resolution computed tomography (CT) and CT expiratory density mask) were compared in the assessment of 29 patients with suspected airways obstruction. Conventional roentgenogram showed a good agreement with the diffusing capacity of the lungs and proved to be useful in predicting the presence of severe emphysema, but the extension of the disease was more precisely assessed by computed tomography. A good agreement was found between high resolution CT and density mask CT, although the "subjective" high resolution identified more patients with mild emphysema than the "automated" density mask. In conclusion, although the plain chest film is useful in the diagnosis of severe emphysema, CT (especially when high resolution is used) is helpful in identifying cases of mild disease and in diagnosing the type of emphysema.

Ultrastructural banding induced by DraI or HaeIII progressive digestion and in situ nick translation on human chromosomes

Fixed human metaphase chromosomes were progressively digested with DraI or HaeIII restriction enzymes, submitted to in situ nick translation, and observed by transmission electron microscopy to obtain further information on the localization of the endonuclease target sequences and on the conformational changes in chromosomal bands. This approach allows us to detect specific nick translation patterns, namely, G-banding or R-like banding after short DraI and HaeIII endonuclease digestion, respectively. Intermediate banding recognizable as C-negative banding and G + C banding are induced by longer HaeIII digestion, before the C-positive banding. These patterns appear to depend both on different target sites of the employed endonucleases and on the DNA loss at different digestion times.

Preparation of chromosome spreads for electron (TEM, SEM, STEM), light and confocal microscopy

In the past, ultrastructural studies on chromosome morphology have been carried out using light microscopy, scanning electron microscopy and transmission electron microscopy of whole mounted or sectioned samples. Until now, however, it has not been possible to use all of these techniques on the same specimen. In this paper we describe a specimen preparation method that allows one to study the same chromosomes by transmission, scanning-transmission and scanning electron microscopy, as well as by standard light microscopy and confocal microscopy. Chromosome plates are obtained on a carbon coated glass slide. The carbon film carrying the chromosomes is then transferred to electron microscopy grids, subjected to various treatments and observed. The results show a consistent morphological correspondence between the different methods. This method could be very useful and important because it makes possible a direct comparison between the various techniques used in chromosome studies such as banding, in situ hybridization, fluorescent probe localization, ultrastructural analysis, and colloidal gold cytochemical reactions.

The behaviour of nuclear domains in the course of apoptosis

Programmed cell death is activated, by different stimuli and in many cell types, to regulate cell population balance during tissue proliferation and embryogenesis. Its initial event seems to be, in most cases, the activation of a Ca(2+)-dependent endonuclease, causing DNA cleavage into nucleosomic fragments. Its morphological expression is characterized by deep nuclear changes, consisting of typical cap-shaped chromatin marginations, followed by nuclear fragmentation and final formation of numerous micronuclei. Cytoplasmic damage appears in a very late stage of the process and the greatest part of the phenomenon appears to take place despite good preservation of the plasma membrane and organellar component. In the present study we analyzed apoptosis in camptothecin-treated HL60 leukaemia cells, and in freshly isolated mouse thymocytes treated with dexamethasone. The process was first quantified and time monitored by flow cytometry. Subsequently the specimens were processed for morphological examination in order to investigate the behaviour of the different nuclear domains. To follow DNA and RNA localization, we utilized osmium ammine and DNase-colloidal gold cytochemical reactions. The concentration of most DNA in the cap-shaped structures was demonstrated by these reactions. Confocal microscopy of cells processed by in situ nick-translation suggested that DNA was firstly cleaved and subsequently condensed in cup-shaped structures. Despite the strong nuclear modifications, nucleoli could be clearly recognized until the late apoptotic stages.

Interleukin 1 alpha stimulates nuclear phospholipase C in human osteosarcoma SaOS-2 cells

Interleukin 1 (IL-1) is one of the most potent stimulators of bone resorption. However, the early biochemical events elicited by IL-1 receptor binding are not fully understood. Here we show that in human osteosarcoma SaOS-2 cells the treatment with IL-1 alpha is able to evoke a rapid and transient increase of nuclear phospholipase C (PLC) activity. A parallel decrease of nuclear phosphatidylinositol monophosphate and phosphatidylinositol bisphosphate is observed. All these events are strictly confined to the nuclear compartment without affecting the cytoplasmatic inositol lipid pool. In addition we show that by Western blot analysis with specific monoclonal antibodies the PLC gamma is located both in the cytoplasm and in the nucleus, while PLC beta appears exclusively localized in the nucleus. Moreover, the increase of PLC activity in response to IL-1 alpha is completely neutralized by monoclonal antibody against the beta-form. While confirming the existence of an autonomous nuclear phosphoinositide signaling system, our data clearly indicate that in SaOS-2 cells one of the earliest events following IL-1 alpha treatment is the breakdown of nuclear phosphatidylinositol monophosphate and phosphatidylinositol bisphosphate because of the activation of a specific nuclear PLC isoform.

Nuclear matrix involvement in sperm head structural organization

In the sperm nuclei the DNA is packaged into a highly condensed form and is not organized into nucleosome and solenoid but is bound and stabilized mainly by the protamines that arrange the DNA in an almost crystalline state. As demonstrated for somatic cells, the sperm DNA has been reported to be organized in loop domains attached to the nuclear matrix structures. However, the possible role of the sperm head matrix in maintaining the loop organization in absence of a typical nucleosomal structures has not been fully elucidated. By using in situ nick translation at confocal and electron microscope level, we analyzed the organization of the DNA-protamine complex and its association with the sperm nuclear matrix. The data obtained indicate that the chromatin organization in sperm nuclei is maintained during the sperm condensation by means of interactions with the nuclear matrix at fixed sites. The fine structure of sperm nucleus and of sperm nuclear matrix, investigated on sections and replicas of freeze-fractured specimens, suggests that the lamellar array, observed by freeze-fracturing in the sperm nuclei, could depend on the inner matrix which presents a regular organization of globular structures possibly involved in the maintenance of chromatin domains in highly condensed sperm nuclei also.

Localization of single copy gene by PRINS technique

Images

Nuclear matrix-bound replicational sites detected in situ by 5-bromodeoxyuridine

The nuclear matrix was prepared in situ from Swiss 3T3 cells, which were synchronized by contact inhibition and serum starvation and pulse-labelled for very short periods of time with 5-bromodeoxyuridine (5-BrdU). For the first time 5-BrdU has been employed to demonstrate the association of newly synthesized DNA with a nucleoskeleton. Immunofluorescence analysis using a monoclonal antibody to 5-BrdU revealed five different intranuclear staining patterns at different stages of the S phase. These patterns were observed also in intact cells and did not change during the matrix preparation steps which involve extraction with 2 M NaCl and DNase I digestion. Such an observation was also confirmed by spatial confocal microscopy studies. The intensity of fluorescence, which was evaluated by cytofluorometry, increased to reach a maximum during mid-S phase and then decreased. Because no significant difference was found in the time to label residual DNA of different 5-BrdU staining patterns, this strongly suggests that a different number of replicons is activated at different stages of the S phase. These results strengthen the hypothesis that eukaryotic DNA replication occurs in close association with an insoluble protein nuclear skeleton, which determines the three-dimensional spatial organization of chromosome duplication.