Co-creation of a school-based sexual health education intervention in Italy

Introduction

School-based sexuality education (SBSE) is the most effective way to positively impact young people's behaviour and attitude towards sexuality. This study describes the development of a SBSE pilot activity targeting lower secondary schools (LSS) within the context of EduforIST project funded by the Italian Ministry of Health.

Methods

A desk review was carried out to collect information about national policies, international literature and guidelines on SE and STIs prevention. An online survey was developed to collect information on SBSE activities implemented in Italy during 2016-2020. Focus groups among project partners and open consultations with a multisectorial expert advisory board were organised. SBSE pilot activity was developed by an interdisciplinary team of pedagogists, public health and SE experts, educators.

Results and discussion

The SBSE was structured in: a) 5 interactive interventions of 2 hours each with students (4 theoretical and practical modules; 1 final intervention for students-led discussion and evaluation); b) introductory and closing meetings with teachers and with parents. The modules addressed the following dimensions: changes in adolescence; emotions and relationships; sexual identities and diversity; sexual consent, STIs/pregnancy prevention, sexual health services. Additional materials were developed: a. pre/post evaluation tools for educators and students; b. pre-implementation checklist for schools; c. materials for teachers’ and parents’ engagement before/after the SBSE activity.

Conclusions

This pilot activity represented a first step towards the development of a standardised, evidence-based and comprehensive approach to SBSE, for future implementation across the country.

School-based sexuality education in Italy 2016-2020: a highly heterogeneous scenario

Background

In Italy, sexuality education (SE) is not part of school curricula. SE and, specifically, comprehensive SE (CSE), as defined by UNESCO, is one of the most important means of promoting sexual well-being among young people and a key component for sexually transmitted infections' (STI) prevention. School-based SE has the potential to reach most young people, is cost-effective and valued by students. The aim of this study was to describe school-based SE educational activities (EA) implemented in Italy during 2016-2020.

Methods

An online survey was developed and piloted to collect information on duration, content and methods used to implement the EA. The survey was disseminated at national and regional level between August-October 2020. IBM SPSS Statistics 26 was used to perform descriptive analysis of the data, while a framework from UNESCO was adapted to perform a qualitative analysis.

Results

A total of 219 reported EA were carried out in secondary schools. The analysis describes a highly heterogeneous scenario in terms of EA geographical coverage across the country (most EA delivered in 4/20 regions), providers (70% private, 30% public) and objectives. The qualitative analysis of content, objectives, and methodology identified 62 EA (29%) classifiable as CSE, with median duration of 3 days. The remainder EA had a risk-based approach, largely focussing on STI prevention (35%). Many EA (29%) were single-session interventions. Limited time availability for extra-curricular activities was reported as a key challenge. Only 97 EA performed evaluation (44%). In 53 EA (24%) both pre and post knowledge assessment were delivered and in 114 (52%) satisfaction was evaluated.

Conclusions

Italy is one of a few European countries still lacking a dedicated policy for school-based SE. According to available data, SE is not systematically and equally delivered across the country. Action is urgently needed to incorporate SE in school curricula. (Funding: Italian Ministry of Health)

Key messages

This study shows the absence of a comprehensive and shared approach to SE in Italy, with heterogeneous geographical coverage and providers and a lack of systematic objectives and evaluation. The results highlight the need to develop theoretical and practical guidelines for the implementation of CSE in Italy and the integration of sexuality education in school curricula.

New Light on the Mechanism of Phototransduction in Phototropin

Phototropins are photoreceptor proteins that regulate blue light-dependent biological processes for efficient photosynthesis in plants and algae. The proteins consist of a photosensory domain that responds to the ambient light and an output module that triggers cellular responses. The photosensory domain of phototropin from Chlamydomonas reinhardtii contains two conserved LOV (light-oxygen-voltage) domains with flavin chromophores. Blue light triggers the formation of a covalent cysteine-flavin adduct and upregulates the phototropin kinase activity. Little is known about the structural mechanism that leads to kinase activation and how the two LOV domains contribute to this. Here, we investigate the role of the LOV1 domain from C. reinhardtii phototropin by characterizing the structural changes occurring after blue light illumination with nano- to millisecond time-resolved X-ray solution scattering. By structurally fitting the data with atomic models generated by molecular dynamics simulations, we find that adduct formation induces a rearrangement of the hydrogen bond network from the buried chromophore to the protein surface. In particular, the change in conformation and the associated hydrogen bonding of the conserved glutamine 120 induce a global movement of the β-sheet, ultimately driving a change in the electrostatic potential on the protein surface. On the basis of the change in the electrostatics, we propose a structural model of how LOV1 and LOV2 domains interact and regulate the full-length phototropin from C. reinhardtii. This provides a rationale for how LOV photosensor proteins function and contributes to the optimal design of optogenetic tools based on LOV domains.

Anti-biofilm activity of pseudoalteromonas haloplanktis tac125 against staphylococcus epidermidis biofilm: Evidence of a signal molecule involvement?

Staphylococcus epidermidis is recognized as cause of biofilm-associated infections and interest in the development of new approaches for S. epidermidis biofilm treatment has increased. In a previous paper we reported that the supernatant of Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 presents an anti-biofilm activity against S. epidermidis and preliminary physico-chemical characterization of the supernatant suggested that this activity is due to a polysaccharide. In this work we further investigated the chemical nature of the anti-biofilm P. haloplanktis TAC125 molecule. The production of the molecule was evaluated in different conditions, and reported data demonstrated that it is produced in all P. haloplanktis TAC125 biofilm growth stages, also in minimal medium and at different temperatures. By using a surface coating assay, the surfactant nature of the anti-biofilm compound was excluded. Moreover, a purification procedure was set up and the analysis of an enriched fraction demonstrated that the anti-biofilm activity is not due to a polysaccharide molecule but that it is due to small hydrophobic molecules that likely work as signal. The enriched fraction was also used to evaluate the effect on S. epidermidis biofilm formation in dynamic condition by BioFlux system.

Effect of betamethasone in combination with antibiotics on gram positive and gram negative bacteria

Betamethasone is an anti-inflammatory steroid drug used in cases of anaphylactic and allergic reactions, of Alzheimer and Addison diseases and in soft tissue injuries. It modulates gene expression for anti-inflammatory activity suppressing the immune system response. This latter effect might decrease the effectiveness of immune system response against microbial infections. Corticosteroids, in fact, mask some symptoms of infection and during their use superimposed infections may occur. Thus, the use of glucocorticoids in patients with sepsis remains extremely controversial. In this study we analyzed the in vitro effect of a commercial formulation of betamethasone (Bentelan) on several Gram positive and Gram negative bacteria of clinical relevance. It was found to be an inhibitor of the growth of most of the strains examined. Also the effect of betamethasone in combination with some classes of antibiotics was evaluated. Antibiotic-steroid combination therapy is, in such cases, superior to antibiotic-alone treatment to impair bacterial growths. Such effect was essentially not at all observable on Staphylococcus aureus or Coagulase Negative Staphylococci (CoNS).

Holo and apo-transferrins interfere with adherence to abiotic surfaces and with adhesion/invasion to HeLa cells in Staphylococcus spp

Staphylococcus aureus and Staphylococcus epidermidis are the major cause of infections associated with implanted medical devices. Colonization on abiotic and biotic surfaces is often sustained by biofilm forming strains. Human natural defenses can interfere with this virulence factor. We investigated the effect of human apo-transferrin (apo-Tf, the iron-free form of transferrin, Tf) and holo-transferrin (holo-Tf, the iron-saturated form) on biofilm formation by CA-MRSA S. aureus USA300 type (ST8-IV) and S. epidermidis (a clinical isolate and ATCC 35984 strain). Furthermore S. aureus adhesion and invasion assays were performed in a eukaryotic cell line. A strong reduction in biofilm formation with both Tfs was obtained albeit at very different concentrations. In particular, the reduction in biofilm formation was higher with apo-Tf rather than obtained with holo-Tf. Furthermore, while S. aureus adhesion to eukaryotic cells was not appreciably affected, their invasion was highly inhibited in the presence of holo-Tf, and partially inhibited by the apo form. Our results suggest that Tfs could be used as antibacterial adjuvant therapy in infection sustained by staphylococci to strongly reduce their virulence related to adhesion and cellular invasion.

A New Anti-Infective Strategy to Reduce Adhesion-Mediated Virulence in Staphylococcus Aureus Affecting Surface Proteins

Staphylococcus aureus is a flexible microbial pathogen frequently isolated from community-acquired and nosocomial infections. The use of indwelling medical devices is associated with a significant risk of infection by this bacterium which possesses a variety of virulence factors, including many toxins, and the ability to invade eukaryotic cells or to form biofilm on biotic and abiotic surfaces. The present study evaluates the anti-infective properties of serratiopeptidase, a secreted protein of Serratia marcescens, in impairing virulence-related staphylococcal properties, such as attachment to inert surfaces and adhesion/invasion on eukaryotic cells. SPEP seems to exert its action by modulating specific proteins. Proteomic studies performed on surface proteins extracted from SPEP-treated S. aureus cultures revealed that a number of proteins are affected by the treatment. Among these we found the adhesin/autolysin Atl, FnBP-A, SecA1, Sbi, EF-Tu, EF-G, and alpha-enolase. EF-Tu, EF-G and alpha-enolase are known to perform a variety of functions, depending on their cytoplasmic or surface localization. All these factors can facilitate bacterial colonization, persistence and invasion of host tissues. Our results suggest that SPEP could be developed as a potential “anti-infective agent” capable to hinder the entry of S. aureus into human tissues, and also impair the ability of this pathogen to form biofilm on prostheses, catheters and medical devices.

Comparison of Anti-Bacterial Prophylactic Properties of Two Different Vascular Grafts: Action of Anti-Bacterial Graft Coating and Systemic Antibiotic Treatment

The main problem associated with artificial vascular devices is the risk of bacterial infections, mostly sustained by coagulase negative staphylococci or Staphylococcus aureus. Many efforts have been made to identify materials refractory to bacterial adhesion. The aim of our study is to verify the antimicrobial properties of two kinds of vascular prosthesis to prevent early onset infections and the efficacy of the concomitant action of a systemic antibiotic treatment. Adult male Wistar rats were used. We subcutaneously implanted in four groups a silver-coated prosthesis fragment, and a rifampicin-soaked prosthesis fragment in the remaining four groups. We inoculated in the site of implant a high bacterial burden of S. aureus in four groups and a low burden in the remaining groups. Systemic levofloxacin was administered for seven days in four groups representing the two kinds of prosthesis; after 21 days the rats were sacrificed, prosthesis fragments were sonicated and the corresponding supernatants were plated for bacterial counts. The rifampicin-soaked prostheses explanted from rats treated with levofloxacin were sterile, regardless of the bacterial inoculum. In other groups some prostheses were colonized. In the experimental rat model used, the action of local and systemic antibiotic treatment was able to reduce colonisation of artificial prostheses.

Outpatient parenteral antibiotic therapy in the elderly: an Italian observational multicenter study

Bacterial infections are the most frequent cause of hospitalization in elderly patients. In the early eighties, the advantages of Outpatient parenteral Antibiotic therapy (OPAT) were identified in the United States, and suitable therapeutic programs were established. In order to understand the different ways of managing OPAT, a National OPAT Registry was set up in 2003 in Italy. This study analyzes data concerning bacterial infections in 176 elderly patients including demographics, therapeutic management, clinical response, and side-effects. Bone and joint infections (48.9%) and skin and soft tissue infections (27.8%) were the most common infections treated with OPAT. Teicoplanin (28.9%) and ceftriaxone (22.1%) were the top two antibiotics chosen. OPAT was mainly performed at a hospital infusion center (52.8%). The clinical success rate was high and side-effects were low (12.6% of cases). Management of bacterial infections in the elderly with an outpatient program is effective and safe.

Outpatient parenteral antibiotic therapy for bone and joint infections: an italian multicenter study

In the early eighties, the advantages of outpatient parenteral antibiotic therapy (OPAT) (reduced costs, no hospitalization trauma in children, no immobilization syndrome in elderly, reduction in nosocomial infections by multiresistant organisms) were identified in the United States, and suitable therapeutic programs were established. Currently, more than 250,000 patients per year are treated according to an OPAT program. In order to understand the different ways of managing OPAT and its results, a National OPAT Registry was set up in 2003 in Italy. Analysis of data concerning osteomyelitis, septic arthritis, prosthetic joint infection and spondylodiskitis, allowed information to be acquired about 239 cases of bone and joint infections, with particular concern to demographics, therapeutic management, clinical response, and possible side effects. Combination therapy was the first-line choice in 66.9% of cases and frequently intravenous antibiotics were combined with oral ones. Teicoplanin (38%) and ceftriaxone (14.7%), whose pharmacokinetic/pharmacodynamic properties permit once-a-day administration, were the two top antibiotics chosen; fluoroquinolones (ciprofloxacin and levofloxacin) were the most frequently utilized oral drugs. Clinical success, as well as patients' and doctors' satisfaction with the OPAT regimen was high. Side-effects were mild and occurred in 11% of cases. These data confirm that the management of bone and joint infections in an outpatient setting is suitable, effective and safe.

Cervical-vaginal disease in HIV immunosuppressed patients: management and present screening programme

The aim of this study was to evaluate the rate of the cervical intraepithelial neoplasia (L-SIL and H-SIL) in HIV-positive patients using cytological, colposcopic and histological examinations. The correlations between these cervical lesions, the role of HPV and the clinical and immunological aspects of HIV infection and inflammatory cervical-vaginal disease were studied. We believe that HPV infection and preneoplastic and/or neoplastic lesions occur more often in immunodepressed HIV-positive patients, and that on the grounds of the high risk of precancerous lesions in this population and the low sensibility of the Pap test, it is advisable to perform a colposcopic examination to discover early lesions that must undergo a specific biopsy.

Epidemiology of onychomycosis and paronychia in the area of ANCONA (ITALY) over a period of 5 years

We retrospectively evaluated the epidemiology of onychomycosis and/or paronychia in 172 patients attending the Clinic of Dermatology and Venereology over a 5 year period. Although yeast isolates, belonging to the Candida species, represented the most frequent etiologic agents of these infections, an increasing prevalence of fungal infections due to emerging fungal pathogens (EFP) was noted throughout this time period. In particular, EFP as causative agents of these infections increased from 0 to 28.4% from 1998 to 2002.

In vitro activity of posaconazole against clinical isolates of dermatophytes

A broth macrodilution method following the recommendations established by the National Committee for Clinical Laboratory Standards was used to compare the in vitro activity of posaconazole (PCZ) with that of itraconazole (ITC) against 30 clinical isolates of dermatophytes belonging to six different species. In terms of MICs, PCZ showed an activity equal to that of ITC. MICs of PCZ at which 50% (MIC(50)) and 90% (MIC(90)) of the isolates were inhibited were 0.5 and > 4.0 microg/ml, respectively. The MIC(50) and MIC(90) of ITC were 1.0 and > 4.0 microg/ml, respectively. However, PCZ showed a more potent fungicidal activity than that of ITC against isolates belonging to the genus Microsporum (P = 0.03). PCZ merits further investigation as a potentially useful agent for treatment of dermatophytosis.

Electrophoretic karyotyping and antifungal susceptibility patterns of Candida parapsilosis clinical isolates causing deep and superficial fungal infections

Forty-six isolates of Candida parapsilosis, each from a single patient, were collected from July 1993 through March 1999 at the University of Ancona Hospitals and Clinics. Twenty-eight strains were isolated from superficial lesioned sites, including skin, nails and other sources while 18 strains were isolated from blood. The isolates were typed by electrophoretic karyotyping (EK) and tested for their susceptibility to fluconazole (FLC), itraconazole (ITC), flucytosine (5-FC), and amphotericin B (AMB). Our data confirmed that EK is a useful technique for DNA typing of isolates of Candida parapsilosis and showed that the source of isolation is not associated with a given DNA type. Although strains belonging to this species of Candida are susceptible to the most common antifungals, including the triazoles, the degree of ITC susceptibility was dose dependent (MIC ranging from 0.25-0.5 microgram/ml) for 98% of the isolates.

Treatment of scabies with ivermectin

The authors report six new cases of patients suffering from severe infestation with the mite sarcoptes scabiei, treated with ivermectin, currently the only oral therapy available for this disease. Each patient received 200 mug/kg of ivermectin, taken as single dose. No topical therapy was undertaken, except for topical treatment with emollient, as needed. The drug was very effective in all cases, easy to use, safe, and particularly useful in those patients with secondary eczematisation and escoriations, for whom the topical treatments are irritant and less well tolerated.

Subclinical joint involvement in psoriasis: magnetic resonance imaging and X-ray findings

Previous studies have shown that magnetic resonance imaging is more sensitive in assessing soft tissue and bone involvement in inflammatory arthritis than conventional radiography. Therefore the main objects of this study were to evaluate the frequency of hand involvement in psoriatic patients free from arthritic symptoms, and to compare the results with those of a healthy control population (age- and sex-matched). Twenty-five patients suffering from active nummular and/or plaque psoriasis with no arthritic signs or symptoms were studied together with 12 healthy control subjects. The articular structures of both hands in all patients were screened using both traditional radiological techniques and magnetic resonance imaging. Specifically, we examined: soft tissue swelling, periarticular effusion, joint effusion-synovial pannus, tendon sheath effusion, bone erosion, luxation, sub-luxation, bone cysts and subchondral signal intensity abnormalities. Sixty-eight percent of our psoriatic patients were found to be positive with at least one arthritic sign using magnetic resonance imaging, while with the standard X-ray procedure, only 32% of the same group of patients were found to be positive. Specifically, abnormal signal intensity in the subchondral focal areas were seen in 9 patients using the magnetic resonance imaging technique, while in the control group, no significant abnormalities were detected. A high percentage of psoriatic patients without apparent arthritic signs and symptoms were shown to have hand articular involvement, in particular in the distension of the capsular and periarticular oedema when examined with magnetic resonance imaging. In our experience, the use of magnetic resonance imaging allows a clear and adequate evaluation of the cartilage, bone and soft tissue material, and is diagnostically superior to X-ray in demonstrating clinically silent and radiologically invisible articular lesions. Moreover, the subchondral changes detected by magnetic resonance imaging were unexpected findings which could imply an ischaemic origin.

In vitro activity of terbinafine against clinical isolates of dermatophytes

A broth macrodilution method following the recommendations established by the National Committee for Clinical Laboratory Standards was employed for testing terbinafine against 20 clinical isolates of dermatophytes belonging to seven species. The minimal inhibitory concentrations resulting in either 80% or 100% inhibition of growth, compared to growth in drug-free control tubes, ranged from </=0.03 to 0.25 g ml-1 and from </=0.03 to 2.0 g ml-1, respectively. Terbinafine was shown to be fungicidal at a concentration of </=1.0 microg ml-1 for 19 isolates. No differences in susceptibilities were found between strains isolated from HIV-positive and -negative individuals.

Tinea capitis due to Microsporum gypseum in an adult

A case of tinea capitis due to Microsporum gypseum in an adult is described. An otherwise healthy 69-year-old woman presented two large patches of slightly erythematous scaling alopecia localized on the vertex and on the left parietal region of the scalp. The only subjective sign was itching. A mycological culture was positive for Microsporum gypseum. Tinea capitis is uncommon in adults; furthermore, isolation of Microsporum gypseum from this type of lesion is rare.

Advances in the understanding of malignant transformation of keratinocytes: an immunohistochemical study

AIM

We set out to investigate the interactions between malignant transformation of keratinocytes, presence of oncoproteins and immunosurveillance in squamous cell carcinoma (SCC) and in a preneoplastic lesion, actinic keratosis (AK).

METHODS

Samples of SCC, AK and normal skin (NS) were subjected to quantitative analysis using the following antibodies: anti-p53, Ki67, OKT6, OK-DR, B7/BB1, anti-CD54, anti-CD11, OKT3, OKT4, OKT8; positivity for ras-p21, EGFr and bcl-2 was evaluated by semiquantitative analysis.

RESULTS

Oncoprotein alterations and increased keratinocyte proliferative activity were observed both in AK and SCC. The number of Langerhans cells (CD1a+ cells) was similar in the two lesions but lower in SCC compared to AK. The proportion of CD1a(+)-B7/BB1+ cells was slightly higher in AK and SCC than in NS. The Langerhans cells expressed the HLA-DR antigen in all groups. Values were highest in AK and NS, and quite low in SCC. Cytotoxic T lymphocytes were more numerous in SCC than in AK and NS. Interestingly, the total CD4/CD8 ratio was much lower in SCC than in AK and NS, which indicates an increase in the CD8+ subpopulation in samples of SCC. In the epithelia of SCC samples there were a considerable number of B7/BB1+ keratinocytes.

CONCLUSIONS

We suggest that alterations in the immunodefence mechanisms have an important role in the transformation of AK into SCC, and that these changes affect not only lymphocytes, but also professional (i.e., Langerhans cells) and non-professional (i.e., keratinocytes) antigen presenting cells.

Hypomelanosis of Ito: a case report with clinical and ultrastructural data

Hypomelanosis of Ito (HI) is an uncommon skin disorder characterized by the presence of hypochromic areas associated with visceral abnormalities, the most common being neurological, muscular, skeletal and ocular. The authors describe a typical case of hypomelanosis of Ito in a 7-year-old child. The patient was obese, suffered from scoliosis, flat feet and had a bilateral genu valgus. No neurological, ophthalmological or dental malformations were noted. An electron microscopic study of a hypomelanotic area showed decreased functional activity in the melanocytes, which contained only a few rudimentary cytoplasmatic projections and poorly developed organelles. In addition, there was a reduction in the number of mature melanosomes.

Skin metastases from prostate cancer associated with malignant melanoma

A 66-year-old man, admitted to the hospital for prostatic carcinoma, presented with a nodular lesion located on the presternal region and a small nodule (0.5 cm in diameter) simulating a scalp sebaceous cyst located on the scalp. Moreover, an irregular darkbrown lesion was observed on the left side of the abdomen, and a brownish macula was also present on the presternal region. Histologic examination of the two nodular lesions revealed cutaneous metastases from prostatic carcinoma. The pigmented lesion, localized on the abdomen, proved to be a superficial spreading melanoma with a maximal depth of 1.36 mm. Histologic examination of the brownish lesion on the presternal region revealed nevus cell nests within the epidermis and in the dermis. We discuss the propensity of developing a secondary cancer in a patient with a primary malignancy.

Topological analysis of the human beta 2-adrenergic receptor expressed in Escherichia coli

We have investigated the topology of the human beta 2-adrenergic receptor expressed in Escherichia coli, using the genetic method described by Beckwith and coworkers. We found that fusions with alkaline phosphatase beyond a certain point on the human beta 2-adrenergic receptor sequence were assembled into the bacterial membrane with the same topology as the human beta 2-adrenergic receptor in the mammalian membrane. The pattern that might have been expected on the basis of the topology of the human beta 2-adrenergic receptor in mammalian membranes was not reflected in the levels of alkaline phosphatase activity of the fusions occurring between the N-terminal region and positions close to the second external domain. Our data suggest that the correct positioning of the N terminus of the receptor depends on the presence of its C-terminal portions.

An epidemiological study on cutaneous diseases of agricultural workers authorized to use pesticides

BACKGROUND

There is an increased risk for agricultural workers to acquire skin problems, but data so far published are still very scarce.

OBJECTIVE

To individualize skin disorders that involved this class of workers.

METHODS

Between 1990 and 1992, 426 agricultural workers, authorized to use pesticides, were examined. The control group consisted of 100 nonagriculture workers, who were age and sex matched.

RESULTS

Some common dermatological diseases, such as vitiligo, psoriasis and seborrheic dermatitis, had an incidence overlapping with that found in the controls. Irritant plant dermatoses (2.5%), episodes of acute systemic intoxication from pesticides (6.8%), onychopathies due to chronic trauma (16%), contact dermatitis of the hands (12%), chilblains (7%) and Favre-Racouchot syndrome (2.5%) showed a higher prevalence in the study group.

CONCLUSION

Farmers were affected mainly by diseases caused by the direct action of chemical agents, either natural or industrial, in addition to climatic and physical agents.

Description of a patient with difficult nosological classification: Goldenhar syndrome or Townes-Brocks syndrome?

The authors report a case of difficult nosological classification. The patient, a 4-year-old female shows facial asymmetry, preauricular tags, anterior displacement of the anus and rib anomalies. Some of these clinical signs are present both in the Goldenhar syndrome and in the Townes-Brocks syndrome.

Chordoma with multiple skin metastases

We report a case of sacral chordoma with numerous skin metastases. Histologically they show the typical 'physaliform cells' expressing simultaneously cytokeratin, S-100 protein, epithelial membrane antigen and vimentin immunoreactivity.

Familial supernumerary nipples and breasts

We report 3 cases of supernumerary breasts in the same family. The presence of glandular tissue (polymastia) was demonstrated by ultrasound examination. No associated kidney lesions were found.

Detection of homologous recombination between yeast artificial chromosomes with overlapping inserts

We have developed a system which facilitates the detection of recombination between Yeast Artificial Chromosomes (YAC's) carrying homologous inserts. The system consists of a classical YAC vector, a new YAC vector and two appropriately labelled yeast strains of opposite mating type. The new YAC vector differs in markers from the canonical YAC vector. To test whether homologous recombination takes place, phage lambda DNA was cloned in the two vectors to provide a region of homology. The two constructs were then introduced into yeast strains of opposite mating type in which the endogenous genes for the selective markers present in the vectors are not expressed. Artificial chromosomes obtained by meiotic recombination are detected in the spores resulting from the mating.

Jaundice and cholestasis: past, present and future ideas

The mechanisms of the bilirubin formation, transport, conjugation and biliary excretion have been extensively studied in the recent past, thereby allowing a more complete and rational approach to the old, but still somehow unknown symptom of jaundice and cholestasis. Based on the most recent physiologic and biochemical data, jaundice and cholestasis have been revisited during and international meeting. This report summarizes what has been established in the field but, most importantly highlights what is still unknown and requires further investigation.

Activation of a cryptic TACTAAC box in the Saccharomyces cerevisiae actin intron

We constructed a translational fusion between the Saccharomyces cerevisiae actin gene and the Escherichia coli beta-galactosidase structural gene such that expression of beta-galactosidase activity required accurate splicing of the actin intron. Using this chimeric gene, we generated a series of internal deletions which removed the TACTAAC box or, in addition, TACTAAC-like sequences within the intron. Analysis of the fusion transcripts produced in these deletions allowed us to conclude that the TACTAAC-like sequence TACTAAG can substitute, albeit inefficiently, for the authentic TACTAAC box in the splicing process. These results indicate that the yeast splicing machinery can utilize a cryptic TACTAAC box, but there are requirements for primary sequence and proper position.

Yeast pre-messenger RNA splicing efficiency depends on critical spacing requirements between the branch point and 3′ splice site

In the yeast Saccharomyces cerevisiae the 5' and 3' splice junctions and the internal branch acceptor site (TACTAAC box) are highly conserved intron elements. Analyses of mutants have demonstrated the importance of each of these elements in the splicing process. In the present report we show by three different analytical approaches (splicing-dependent beta-galactosidase expression, in vitro splicing assays and in vivo RNA analyses) that at least two of these elements (the TACTAAC and 3' splice signals) also have to fulfill certain spacing requirements to allow efficient splicing to occur. In particular, the spacing of the 3' splice site from the 2'-5' branch site is a critical factor in determining the efficiency for completion of the final reactions of splicing, intron release and exon-exon joining. Whereas insertions within this region have little or no effect on the first reactions in splicing (the 5' cleavage and 2'-5' branch formation), they dramatically affect the efficiency of the final reactions. In contrast, a 15-base deletion between these two sites has no detectable effect on splicing efficiency. We also show that the 5' cleavage and branch formation can take place, albeit inefficiently, in transcripts in which all of the yeast sequences downstream of the branch site have been replaced by Escherichia coli sequences. We conclude from these studies that, in yeast, the 5' and 3' splice sites are recognized independently from one another, but always in conjunction with the TACTAAC signal.

A human dihydrofolate reductase pseudogene and its relationship to the multiple forms of specific messenger RNA

The presence of dihydrofolate reductase (DHFRase)-specific sequences that, in contrast to the normal DHFRase gene, are not amplified in a methotrexate-resistant cell line, has been detected in the DNA from human sperm and from several human cell lines. DNA fragments containing some of these sequences have been isolated from a cosmid library of human sperm DNA. One of these fragments contains a DHFRase pseudogene (psi HD1) that completely lacks introns, has 92% sequence homology to the corresponding region of normal DHFRase complementary DNA, but exhibits several alterations that make it nonfunctional. The sequence analysis of the inserts of four different plasmids containing the reading frame and varying lengths of the 3' non-coding regions of human DHFRase-specific cDNAs has revealed that the 3' non-coding segments all are colinear in their corresponding portions. Furthermore, the data indicate that the cDNA of one of the plasmids is probably derived from the smallest of the three main human DHFRase messenger RNAs, the 0.8 X 10(3) base (0.8 kb) mRNA, the cDNA of two others, from the 1.0 kb mRNA, and the cDNA of the fourth, from a longer mRNA. These results are consistent with the idea that the multiple forms of DHFRase mRNA in human cells derive from the same gene by different transcription or RNA-processing events. Moreover, the sequence comparison between the psi HD1 and the different DHFRase cDNAs clearly indicates that, if an mRNA intermediate has participated in the formation of this pseudogene, a form of mRNA larger than the 1.0 kb mRNA, probably the 3.8 kb mRNA, must have been involved.

On evolutionarily conserved simple repetitive DNA sequences: do "sex-specific" satellite components serve any sequence dependent function?

The nuclear genomes of eukaryotes contain DNA of varying degrees of repetition. Highly repetitious DNA and simple repetitive sequences as a fraction thereof appear to be distributed in a non-random fashion in the genome. There are arguments for and against functional roles of simple repetitive sequences, and the reasons for their evolutionary conservation are not at all clear. In order to learn more about the biologic role of simple repetitive sequences in the context of their evolutionary history, we report here the following results from studies of sex-specific snake satellite DNA: 1) The snake simple repeat sequence is 5'-GATAGACA-3' and it is strictly conserved throughout vertebrate evolution. 2) The simple repeat sequence is intimately interspersed with single-copy DNA throughout the mouse genome. 3) The simple repeat is transcribed into RNA in several animal systems and it is translatable in bacterial test systems. 4) The simple repeat sequence is sex-specifically arranged in vertebrates. 5) In snake DNA, the simple repeat is adjacent to a single-copy sequence which singles out a male-specific putative mRNA in mouse polysomal poly (A)+ RNA. Thus even if this snake simple repetitive sequence is not involved in a basic cellular function such as sex-determination, it is nevertheless a valuable tool to approach those problems.