Multifunctional scaffolds for biomedical applications: Crafting versatile solutions with polycaprolactone enriched by graphene oxide

The pressing need for multifunctional materials in medical settings encompasses a wide array of scenarios, necessitating specific tissue functionalities. A critical challenge is the occurrence of biofouling, particularly by contamination in surgical environments, a common cause of scaffolds impairment. Beyond the imperative to avoid infections, it is also essential to integrate scaffolds with living cells to allow for tissue regeneration, mediated by cell attachment. Here, we focus on the development of a versatile material for medical applications, driven by the diverse time-definite events after scaffold implantation. We investigate the potential of incorporating graphene oxide (GO) into polycaprolactone (PCL) and create a composite for 3D printing a scaffold with time-controlled antibacterial and anti-adhesive growth properties. Indeed, the as-produced PCL-GO scaffold displays a local hydrophobic effect, which is translated into a limitation of biological entities-attachment, including a diminished adhesion of bacteriophages and a reduction of E. coli and S. aureus adhesion of ∼81% and ∼69%, respectively. Moreover, the ability to 3D print PCL-GO scaffolds with different heights enables control over cell distribution and attachment, a feature that can be also exploited for cellular confinement, i.e., for microfluidics or wound healing applications. With time, the surface wettability increases, and the scaffold can be populated by cells. Finally, the presence of GO allows for the use of infrared light for the sterilization of scaffolds and the disruption of any bacteria cell that might adhere to the more hydrophilic surface. Overall, our results showcase the potential of PCL-GO as a versatile material for medical applications.

Deep learning for MYC binding site recognition

Motivation: The definition of the genome distribution of the Myc transcription factor is extremely important since it may help predict its transcriptional activity particularly in the context of cancer. Myc is among the most powerful oncogenes involved in the occurrence and development of more than 80% of different types of pediatric and adult cancers. Myc regulates thousands of genes which can be in part different, depending on the type of tissues and tumours. Myc distribution along the genome has been determined experimentally through chromatin immunoprecipitation This approach, although powerful, is very time consuming and cannot be routinely applied to tumours of individual patients. Thus, it becomes of paramount importance to develop in silico tools that can effectively and rapidly predict its distribution on a given cell genome. New advanced computational tools (DeeperBind) can then be successfully employed to determine the function of Myc in a specific tumour, and may help to devise new directions and approaches to experiments first and personalized and more effective therapeutic treatments for a single patient later on. Results: The use of DeeperBind with DeepRAM on Colab platform (Google) can effectively predict the binding sites for the MYC factor with an accuracy above 0.96 AUC, when trained with multiple cell lines. The analysis of the filters in DeeperBind trained models shows, besides the consensus sequence CACGTG classically associated to the MYC factor, also the other consensus sequences G/C box or TGGGA, respectively bound by the SP1 and MIZ-1 transcription factors, which are known to mediate the MYC repressive response. Overall, our findings suggest a stronger synergy between the machine learning tools as DeeperBind and biological experiments, which may reduce the time consuming experiments by providing a direction to guide them.

Different types of abstract concepts: evidence from two neurodegenerative patients

The observation of neurological patients showing selective impairments for specific conceptual categories contributed in the development of semantic memory theories. Here, we studied two patients (P01, P02), affected, respectively, by the semantic variant of Primary Progressive Aphasia (sv-PPA) and Cortico-Basal Syndrome (CBS). An implicit lexical decision task, including concrete (animals, tools) and abstract (emotions, social, quantity) concepts, was administered to patients and healthy controls.P01 and P02 showed an abolished priming effect for social and quantity-related concepts, respectively. This double dissociation suggests a role of different brain areas in representing specific abstract categories, giving insights for current semantic memory theories.

Graphene oxide touches blood: in vivo interactions of bio-coronated 2D materials

Graphene oxide is the hot topic in biomedical and pharmaceutical research of the current decade. However, its complex interactions with human blood components complicate the transition from the promising in vitro results to clinical settings. Even though graphene oxide is made with the same atoms as our organs, tissues and cells, its bi-dimensional nature causes unique interactions with blood proteins and biological membranes and can lead to severe effects like thrombogenicity and immune cell activation. In this review, we will describe the journey of graphene oxide after injection into the bloodstream, from the initial interactions with plasma proteins to the formation of the "biomolecular corona", and biodistribution. We will consider the link between the chemical properties of graphene oxide (and its functionalized/reduced derivatives), protein binding and in vivo response. We will also summarize data on biodistribution and toxicity in view of the current knowledge of the influence of the biomolecular corona on these processes. Our aim is to shed light on the unsolved problems regarding the graphene oxide corona to build the groundwork for the future development of drug delivery technology.

Gfi-1 inhibits proliferation and colony formation of p210BCR/ABL-expressing cells via transcriptional repression of STAT 5 and Mcl-1

Expression of the transcription repressor Gfi-1 is required for the maintenance of murine hematopoietic stem cells. In human cells, ectopic expression of Gfi-1 inhibits and RNA interference-mediated Gfi-1 downregulation enhances proliferation and colony formation of p210BCR/ABL expressing cells. To investigate the molecular mechanisms that may explain the effects of perturbing Gfi-1 expression in human cells, Gfi-1-regulated genes were identified by microarray analysis in K562 cells expressing the tamoxifen-regulated Gfi-1-ER protein. STAT 5B and Mcl-1, two genes important for the proliferation and survival of hematopoietic stem cells, were identified as direct and functionally relevant Gfi-1 targets in p210BCR/ABL-transformed cells because: (i) their expression and promoter activity was repressed by Gfi-1 and (ii) when constitutively expressed blocked the proliferation and colony formation inhibitory effects of Gfi-1. Consistent with these findings, genetic or pharmacological inhibition of STAT 5 and/or Mcl-1 markedly suppressed proliferation and colony formation of K562 and CD34+ chronic myelogenous leukemia (CML) cells. Together, these studies suggest that the Gfi-1STAT 5B/Mcl-1 regulatory pathway identified here can be modulated to suppress the proliferation and survival of p210BCR/ABL-transformed cells including CD34+ CML cells.

Mortality and cause of death among psychiatric patients: a 20-year case-register study in an area with a community-based system of care

BACKGROUND

Most mortality studies of psychiatric patients published to date have been conducted in hospital-based systems of care. This paper describes a study of the causes of death and associated risk factors among psychiatric patients who were followed up over a 20-year period in an area where psychiatric care is entirely provided by community-based psychiatric services.

METHOD

All subjects in contact with the South Verona Community-based Mental Health Service (CMHS) over a 20-year period with an ICD-10 psychiatric diagnosis were included. Of these 6956 patients, 938 died during the study period. Standardized mortality ratios (SMRs) and Poisson multiple regressions were used to assess the excess of mortality in the sample compared with the general population.

RESULTS

The overall SMR of the psychiatric patients was 1.88. Mortality was significantly high among out-patients [SMR 1.71, 95% confidence interval (CI) 1.6-1.8], and higher still following the first admission (SMR 2.61, 95% CI 2.4-2.9). The SMR for infectious diseases was higher among younger patients and extremely high in patients with diagnoses of drug addiction (216.40, 95% CI 142.5-328.6) and personality disorders (20.87, 95% CI 5.2-83.4).

CONCLUSIONS

This study found that psychiatric patients in contact with a CMHS have an almost twofold higher mortality rate than the general population. These findings demonstrate that, since the closure of long-stay psychiatric hospitals, the physical health care of people with mental health problems is often neglected and clearly requires greater attention by health-care policymakers, services and professionals.

Avoidable mortality of psychiatric patients in an area with a community-based system of mental health care

OBJECTIVE

To ascertain the existence of an excess of avoidable mortality among psychiatric patients in an area with a community-based system of care, to identify predictors of higher risk of avoidable mortality and to provide some possible indication to reduce avoidable mortality in modern psychiatric services.

METHOD

All patients with an ICD-10 psychiatric diagnosis, living in a catchment area of about 75,000 inhabitants, seeking care in 1982-2001 were included (n = 6956). Mortality and causes of death were ascertained using linkage procedures with other local health databases. Standardized mortality ratios (SMRs) were calculated for each avoidable cause of death.

RESULTS

The observed number of deaths for those causes considered avoidable by the European Community was four times greater than the expected (P < 0.01). SMR was higher for deaths preventable with adequate health promotion policies than for those preventable with appropriate health care. Males, alcohol/drug addicted and young patients have the highest avoidable SMRs.

CONCLUSION

These findings urgently call for the implementation of health promotion and preventive programs targeted to psychiatric patients. Moreover, mental health services should improve the capacity to manage medical health problems of their patients.

Genome-wide scan supports the existence of a susceptibility locus for schizophrenia and bipolar disorder on chromosome 15q26

Schizophrenia (SZ) and bipolar disorder (BPD) are two severe psychiatric diseases with a strong genetic component. In agreement with the 'continuum theory', which suggests an overlap between these disorders, the existence of genes that affect simultaneously susceptibility to SZ and BPD has been hypothesized. In this study we performed a 7.5 cM genome scan in a sample of 16 families affected by SZ and BPD, all originating from the same northeast Italian population. Using both parametric and non-parametric analyses we identified linkage peaks on four regions (1p, 1q, 4p and 15q), which were then subjected to a follow-up study with an increased marker density. The strongest linkage was obtained on chromosome 15q26 with a non-parametric linkage of 3.05 for marker D15S1014 (nominal P=0.00197). Interestingly, evidence for linkage with the same marker has been reported previously by an independent study performed on SZ and BPD families from Quebec. In this region, the putative susceptibility gene ST8SIA2 (also known as SIAT8B) was recently associated with SZ in a Japanese sample. However, our allele frequency analyses of the two single-nucleotide polymorphisms (SNPs) with putative functional outcome (rs3759916 and rs3759914) suggest that these polymorphisms are unlikely to be directly involved in SZ in our population. In conclusion, our results support the presence of a gene in 15q26 that influences the susceptibility to both SZ and BPD.

Altered gene silencing and human diseases

Epigenetic regulation of gene expression is mediated through several mechanisms, including modifications in DNA methylation, covalent modifications of core nucleosomal histones, rearrangement of histones and RNA interference. It is now clear that deregulation of epigenetic mechanisms cooperates with genetic alterations in the development and progression of several Mendelian disorders. Here, we summarize the recent findings that highlight how certain inherited diseases, such as Rett syndrome, Immunodeficiency-centromeric instability-facial anomalies syndrome, and facioscapulohumeral muscular dystrophy, result from altered gene silencing.

Health-related quality of life in Italian patients with systemic lupus erythematosus. II. Role of clinical, immunological and psychological determinants

OBJECTIVE

To investigate the role of clinical, immunological and psychological variables in influencing the health-related quality of life (HRQOL) of Italian patients with systemic lupus erythematosus (SLE).

METHODS

The Medical Outcomes Study Short Form-36 was applied in a cohort of 126 SLE patients. At the time of HRQOL testing all patients underwent a clinical and laboratory evaluation, together with the measure of disease activity, severity and damage. In addition, a battery of psychological tests including the Hamilton Anxiety Scale (HAS) and the Hamilton Depression Rating scale (HAM-D) was applied.

RESULTS

The parameters which seemed to greatly influence the impairment of HRQOL were older age, arthralgia-arthritis and higher HAS scores as well as HAM-D. In multivariate analysis (adjusted for age), arthralgia-arthritis and a higher HAM-D score were associated with HRQOL impairment. No relationship between HRQOL and SLE activity, severity or damage were found. However, a relationship between HAS or HAM-D scores and damage or arthralgia-arthritis was noted.

CONCLUSION

Anxiety, depression and joint pain seem to be the major determinants of HRQOL impairment in SLE patients. Damage seems to influence HRQOL mostly through depression.

Health-related quality of life in Italian patients with systemic lupus erythematosus. I. Relationship between physical and mental dimension and impact of age

OBJECTIVE

To examine health-related quality of life (HRQOL) in Italian patients with systemic lupus erythematosus (SLE) and compare it with that of healthy people, and to investigate relationships among different dimensions and subscales of a generic health status measure.

METHODS

The Medical Outcomes Study Short Form-36 (SF-36) was applied in a cohort of 126 consecutive SLE patients and 96 healthy controls. At the time of HRQOL testing, all patients underwent clinical and laboratory evaluation.

RESULTS

Both physical (PCS) and mental (MCS) component summary scores of the SF-36 were reduced in patients compared with controls. In SLE great variability in all the subscales was observed. Significant correlations between PCS and MCS and between many different subscales were observed in patients but not in controls. The PCS was higher than MCS more frequently in controls than in SLE patients (81 vs 48.4%, P<0.00001). In SLE, HRQOL tended to worsen with age.

CONCLUSION

Both PCS and MCS contribute to the decrease in HRQOL in SLE patients. In SLE the mutual interaction between these two dimensions seems to be more relevant than in healthy people.

[Quality of life in systemic lupus erythematosus]

The SF-20 and the SF-36 are the most frequently used questionnaires for assessing the quality of life in SLE patients. The SF-36 is actually considered the most suitable for this disease, due to the inclusion of fatigue, a manifestation frequently observed in SLE patients. Using these instruments, it has been clearly demonstrated that patients with SLE have a worse quality of life than healthy people of the same age. Some aspects of daily life, like physical activity, job, social relationship and vitality, are particularly affected. In the majority of studies, an inverse relation between quality of life and disease activity has been observed. The influence the damage has on the quality of life is more complex, since a greater number of variables are involved. In fact, the amount of damage largely depends on the organ involved and on functional impairment resulting from it. To explain the variability in the quality of life among different patients, it is important to consider, besides the clinical complaints, the psycho-social dimension of each person. In fact, some SLE patients, unlike others, cope well with the disease. People behave differently when faced with critical situations, i.e. after being diagnosed with a chronic disease; their reaction depends on the degree of support they receive from family, friends and colleagues, and from the different strategies of coping, that they use.

Neurotrophin p75 receptor is involved in neuronal damage by prion peptide-(106-126)

In this work we have investigated the molecular basis of the neuronal damage induced by the prion peptide by searching for a surface receptor whose activation could be the first step of a cascade of events responsible for cell death. By using a human neuroblastoma cell line lacking all the neurotrophin receptors and derived clones expressing the full-length or truncated forms of the low affinity neurotrophin receptor (p75(NTR)), we have been able to demonstrate that the neuronal death induced by the prion protein fragment PrP-(106-126) is an active process mediated by a) the binding of the peptide to the extracellular region of p75(NTR), b) the signaling function of the intracytoplasmic region of the receptor, and c) the activation of caspase-8 and the production of oxidant species.

Expressing the human genome

We have searched the human genome for genes encoding new proteins that may be involved in three nuclear gene expression processes: transcription, pre-messenger RNA splicing and polyadenylation. A plethora of potential new factors are implicated by sequence in nuclear gene expression, revealing a substantial but selective increase in complexity compared with Drosophila melanogaster and Caenorhabditis elegans. Although the raw genomic information has limitations, its availability offers new experimental approaches for studying gene expression.

Profound misregulation of muscle-specific gene expression in facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is a neuromuscular disorder characterized by an insidious onset and progressive course. The disease has a frequency of about 1 in 20,000 and is transmitted in an autosomal dominant fashion with almost complete penetrance. Deletion of an integral number of tandemly arrayed 3.3-kb repeat units (D4Z4) on chromosome 4q35 is associated with FSHD but otherwise the molecular basis of the disease and its pathophysiology remain obscure. Comparison of mRNA populations between appropriate cell types can facilitate identification of genes relevant to a particular biological or pathological process. In this report, we have compared mRNA populations of FSHD and normal muscle. Unexpectedly, the dystrophic muscle displayed profound alterations in gene expression characterized by severe underexpression or overexpression of specific mRNAs. Intriguingly, many of the deregulated mRNAs are muscle specific. Our results suggest that a global misregulation of gene expression is the underlying basis for FSHD, distinguishing it from other forms of muscular dystrophy. The experimental approach used here is applicable to any genetic disorder whose pathogenic mechanism is incompletely understood.

The hepatitis B pX protein promotes dimerization and DNA binding of cellular basic region/leucine zipper proteins by targeting the conserved basic region

The hepatitis B virus pX protein is a potent transcriptional activator of viral and cellular genes whose mechanism of action is poorly understood. Here we show that pX dramatically stimulates in vitro DNA binding of a variety of cellular proteins that contain basic region/leucine zipper (bZIP) DNA binding domains. The basis for increased DNA binding is a direct interaction between pX and the conserved bZIP basic region, which promotes bZIP dimerization and the increased concentration of the bZIP homodimer then drives the DNA binding reaction. Unexpectedly, we found that the DNA binding specificity of various pX-bZIP complexes differs from one another and from that of the bZIP itself. Thus, through recognition of the conserved basic region, pX promotes dimerization, increases DNA binding, and alters DNA recognition. These properties of pX are remarkably similar to those of the human T-cell lymphotrophic virus type I Tax protein. Although Tax and pX are not homologous, we show that the regions of the two proteins that stimulate bZIP binding contain apparent metal binding sites. Finally, consistent with this in vitro activity, we provide evidence that both Tax and pX activate transcription in vivo, at least in part, by facilitating occupancy of bZIPs on target promoters.

[The follow-up of the heart transplant patient]

The authors' purpose is to describe the follow-up of heart-transplant patients after they are released from the heart transplant center and entrusted to their personal physicians and/or to peripheral hospital centers. Three principle periods have been identified. FIRST THREE MONTHS: This period is characterized by a high risk of morbidity and mortality due to the various hemodynamic, immunologic and infectious problems present after transplantation. These problems require careful clinical and laboratory monitoring for diagnostic identification and correct treatment. Because of the complexity of procedures such as endomyocardial biopsy, infusion therapy and incidental pacemaker installation, the patient must be attended to by the heart transplant center. FROM THE THIRD MONTH TO THE FIRST YEAR: This corresponds to the period in which the subject is definitively released from the hospital to his or her own home. The aggressive immunologic action slows down and the first iatrogenic complications arise. Without neglecting the risk of rejection, it is also very important to monitor infectious complications, especially the ones caused by bacterial and/or mycotic agents even after minor incidents. This is particularly true when the patient resumes his own daily and work activity, which must nevertheless be encouraged and aided. The follow-up can be done by peripheral hospital centers, as long as the patients stay in close contact with the transplant center. AFTER THE FIRST YEAR: A satisfactory balance with the cellular immunologic action is achieved and the graft begins to suffer from the slow action of circulating antibodies, whose principle target is the coronary endothelium. Coronary artery disease begins to progress with multiple myocardial ischemic consequences: this represents the chronic rejection phenomenology. There is a further complication in the follow-up of these patients, i.e. the high incidence of neoplasms, particularly lymphomas and skin tumors supported by the immunosuppressive treatment. Together, coronary artery disease and neoplasms represent the most important factors in late mortality (34%).

Plasma interleukin-1 beta and tumor necrosis factor concentrations in obsessive-compulsive disorders

Plasma interleukin-1 beta (Il-1 beta) and tumor necrosis factor-alpha (TNF-alpha) concentrations were measured twice, at a 48-hour interval, in 27 drug-free obsessive-compulsive patients (12 women and 15 men) and in 27 sex-age-matched healthy controls. Il-1 beta and TNF-alpha concentrations were significantly lower in patients than in controls, whereas there were no differences in either group between men and women, between the samples of the two days, or, in the patients, between those who had and those who had not been previously treated with psychopharmacologic drugs.

[Formulation and stability of suspensions for preclinical study]

In preclinical studies, poorly soluble drugs are usually administered orally to experimental animals as suspensions. The present study was aimed at providing data allowing predictive estimations of the stability of such suspensions. To this purpose aqueous suspensions of three drugs (griseofulvin, ibuprofen and indomethacin) were prepared at different concentrations using four different suspending agents: sodium carboxymethylcellulose (CMC), microcrystalline cellulose/carboxymethylcellulose (MC/CMC), hydroxypropylmethylcellulose (HPMC) and jota carragenaan (CJ). The physical and physico-chemical characteristics of the drugs, the rheological properties of the suspending media and of the corresponding drug suspensions, and the physical and chemical stability of the suspensions was then evaluated. The type of suspending agent, rather than the physical characteristics of the drug, appeared to exert the main influence on the physical stability of suspensions. The most stable formulations were produced by suspending agents with low-temperature gelation characteristics (CJ) or with thixotropic flux (MC/CMC).

A repeated element in the human lamin B2 gene covers most of an intron and reiterates the exon/intron junction

Nuclear lamins are intermediate filament-type proteins forming a fibrillar meshwork that underlies the inner nuclear membrane. We have previously reported the identification of the human lamin B2 gene that maps to the subtelomeric band p13.3 of chromosome 19 in close proximity of a human DNA replication origin. Here we report the identification within the human lamin B2 gene of a novel repeated element (variable number of tandem repeats: VNTR) that appears to have a very recent origin, being absent in the genome of mouse and primates such as cercopitheques, lemurs and macaques. The VNTR is adjacent to exon 8 of the lamin B2 gene which, albeit encoding the nuclear localization signal of the protein, is highly divergent both at amino acid and nucleotide level among species. Moreover the VNTR, characterized by a repeated unit of about 100 bp, covers most of intron 8 of the gene and reiterates both the last 7 bp of the upstream exon and the exon/intron junction. RT-PCR experiments carried out on HeLa cell RNA suggest that none of the downstream junctions is used during the processing of the lamin B2 pre-mRNA.

Noradrenergic receptor sensitivity in obsessive compulsive disorder: II. Cortisol response to acute clonidine administration

Sensitivity of pre-synaptic alpha-2- and post-synaptic alpha-1- and beta-adrenoceptors was investigated in 15 patients with obsessive-compulsive disorder (OCD) and in 15 age- and sex-matched healthy controls, by measuring cortisol responses to saline administration and to inhibition by clonidine (clon), a noradrenergic receptor agonist. Basal values of cortisol and responses to administration of saline and of clon were the same in patients and controls.

Noradrenergic receptor sensitivity in obsessive-compulsive disorders: I. Growth hormone response to clonidine stimulation

In 15 patients with obsessive-compulsive disorder (OCD) and in 15 healthy controls postsynaptic alpha-2-adrenoceptor sensitivity was examined by measuring the growth hormone (GH) response to growth hormone-releasing hormone (GHRH) and to clonidine stimulation. Basal values of GH and somatomedin-C (SMD-C) and mean GH responses to GHRH were the same in patients and controls, thus suggesting that a peripheral pathology of the somatotropic axis should not be present. GH responses to clonidine stimulation were blunted in patients suggesting that post-synaptic alpha-2-adrenoceptors are subsensitive, possibly due to higher than normal noradrenergic secretion.

Effect of suleparoide on fibrinolysis in the anterior chamber of rabbits

Intra-ocular fibrin deposition following ocular surgery is a serious postoperative complication. The current management of severe postoperative fibrin response is usually ineffective. A quantitative model of fibrin deposition in the rabbit anterior chamber was used to assess the efficacy of Suleparoide I.N.N. (HHS-5) in preventing fibrin formation and in promoting the clearance of fibrinous membranes. Citrated human plasma was injected intracamerally after paracentesis to induce the formation of fibrin clots: 10 min or 24 h after plasma injection, solutions of HHS-5 at different concentrations were injected into the anterior chamber of rabbits. Intra-ocular HHS-5 injection 10 min after plasma injection prevented the formation of fibrinous membranes in a dose-dependent fashion in almost all treated animals. When HHS-5 was injected at 24 h after fibrin clot formation, a reduction of clot areas was observed but the membranes did not completely disappear. No evidence of ocular toxicity was detected by slit-lamp biomicroscopy, intra-ocular pressure and corneal thickness measurements. On the basis of the results obtained with the present animal model, HHS-5 appears as an effective and safe agent for the prevention of fibrinous membrane formation. The data suggest a potential use of HHS-5 for the prophylaxis of fibrin formation in human eyes undergoing extensive intraocular surgery, or in diabetic patients where a hypercoagulable state may be present.

Recognition of bZIP proteins by the human T-cell leukaemia virus transactivator Tax

Human T-cell leukaemia virus type I (HTLV-I) Tax protein increases the DNA binding of many cellular transcription factors that contain a basic region-leucine zipper (bZIP) DNA-binding domain. bZIP domains comprise a leucine-rich dimerization motif and a basic region that mediates DNA contact. How Tax recognizes diverse bZIPs is not understood. Here we show that no specific sequence of the leucine zipper is required for a Tax response. In contrast, the basic region is essential for the Tax-mediated DNA-binding increase, which can be eliminated by single substitutions of several conserved amino acids. Surprisingly, Tax alters the relative affinity of a bZIP for different DNA binding sites. Thus, through recognition of the conserved basic region. Tax increases DNA binding and modifies DNA site selection. Tax provides a model for how a single auxiliary factor can regulate multiple sequence-specific DNA-binding proteins.

Fine mapping of a replication origin of human DNA

A highly sensitive procedure was developed for the identification of the origin of bidirectional DNA synthesis in single-copy replicons of mammalian cells. The method, which does not require cell synchronization or permeabilization, entails the absolute quantification, by a competitive PCR procedure in newly synthesized DNA samples, of the abundance of neighboring DNA fragments distributed along a given genomic region. This procedure was utilized for mapping the start site of DNA replication in a 13.7-kb region of human chromosome 19 coding for lamin B2, which is replicated immediately after the onset of S phase in HL-60 cells. Within this region, DNA replication initiates in a 474-bp area corresponding to the 3' noncoding end of the lamin B2 gene and the nontranscribed spacer between this gene and the 5' end of another highly transcribed one. This localization was obtained both in aphidicolin-synchronized and in exponentially growing HL-60 cells.

Imipramine in alopecia areata. A double-blind, placebo-controlled study

Alopecia areata (AA) is a dermatologic disease whose onset is significantly associated to life events. Its course may often be characterized by high levels of anxiety and depression. These observations suggested a rationale for using an antidepressant in AA. Thirteen patients were enrolled in a double-blind, placebo-controlled study of efficacy of imipramine in alopecia. After six months clinically significant hair regrowth occurred in 5 of the 7 patients on imipramine, whereas no response was observed in the placebo group. An improvement in psychic symptomatology was present in both groups. Our preliminary results indicate the potential efficacy of imipramine in patients with AA, not acting directly through a reduction of anxiety or depression.

Searching for replication origins in mammalian DNA

The attempts at identifying precise replication origins (ori) in mammalian DNA have been pursued mainly through physico-chemical and biochemical approaches, in view of the essential failure of the search for autonomously replicating sequences in cultured cells. These approaches involve the mapping of short stretches of nascent DNA, the identification of the regions where either leading or lagging strands switch polarity, or the localization of replication intermediates by two-dimensional gel electrophoresis. Due to the complexity of animal cell genomes, most of these studies have been performed on amplified domains and with the use of synchronization procedures. The results obtained have been controversial. In order to avoid the use of experimental procedures potentially affecting the physiological mechanism of DNA replication, we have developed a method for the localization of ori in single-copy loci in exponentially growing cells. This method entails the absolute quantification of the abundance of selected DNA fragments along a genomic region within samples of newly synthesized DNA by competitive polymerase chain reaction (PCR); the latter is immune to all the uncontrollable variables which severely affect the reproducibility of conventional PCR. The application of this method to SV40 ori-driven plasmid replication precisely identifies the known ori localization. Using the same approach, we have mapped an ori for bi-directional DNA replication in a 13.7-kb locus of human chromosome 19 encoding lamin B2.

A human DNA replication origin: localization and transcriptional characterization

A single-copy 13.7 kb human DNA region (L30E) located on Ch. 19 p13.3 contains an origin of DNA replication in myeloid HL-60 cells. The origin was localized, by means of quantitative PCR within approximately 3000 bp, in a highly transcribed region containing at least two closely spaced genes with the same polarity of transcription, one encoding lamin B2 and the other an unidentified protein. The origin region overlaps an undermethylated "CpG island" at the 5'-end of the second transcription unit. A binding site (CACGTG) for basic helix-loop-helix (bHLH) DNA binding proteins such as USF/MLTF or MYC-MAX was located by DNase I footprinting analysis in the promoter of the second gene. DMSO differentiation of HL-60 cells, that completely shuts off replication, also drastically reduces the transcription of L30E region. On the other hand such treatment does not modify the methylation pattern of the CpG island and does not abolish the DNase I protection of the bHLH binding site.

The gene for a novel human lamin maps at a highly transcribed locus of chromosome 19 which replicates at the onset of S-phase

A previously described human DNA fragment which is replicated early in S-phase of HL-60 cell DNA (C. Tribioli, G. Biamonti, M. Giacca, M. Colonna, S. Riva, and A. Falaschi, Nucleic Acids Res. 15:10211-10232, 1987) was used to screen a genomic library in lambda Ch28. A clone which contained a 13.7-kb insert (L30E) found to code for several transcripts was isolated. The transcription of L30E DNA exhibited a complex pattern and a tissue-specific and proliferation-dependent type of regulation. The data were consistent with two tandemly arranged transcription units, the 3' end of one separated from the 5' end of the other by a sequence of about 600 bp containing an active promoter. The isolation and sequencing of L30E-specific cDNAs permitted identification of two genes, one of which encoded a B-type human lamin (analogous to mouse lamin B2). L30E DNA was mapped by in situ hybridization at the G-negative subtelomeric band p13.3 of chromosome 19. Interestingly, in synchronized HL-60 cells, L30E DNA is replicated in the first minute of S-phase. Replication of the lamin gene early in S-phase may reflect a coupling between early replication and transcription of genes for S-phase-specific proteins such as lamins.

[Anti-rubella vaccine coverage in women 11-28 years of age: data on 5 local socio-health units of Veneto]

Selective rubella vaccination in the 11 years old girls, has been carried out in the Regione Veneto (Venetian Land) since 1974. The rubella immunization rate in teh women born between 1962 and 1978, in five sanitary districts, is 68.25%; the trend of increasing vaccination is continuing. Important differences in the organization of vaccination campaign were found among the five districts.

Expression of doxorubicin-daunorubicin resistance genes in different anthracycline-producing mutants of Streptomyces peucetius

Two DNA fragments, ric1 and ric2, were isolated from the Streptomyces peucetius 7600 mutant, which produces daunorubicin and doxorubicin, on the basis of their abilities to confer doxorubicin and daunorubicin resistance to Streptomyces lividans. These two fragments are unrelated by restriction mapping and do not show any homology by Southern analysis, yet both of them increase the level of resistance 10-fold in transformed S. lividans. Functional analysis revealed that ric1 also contains two genes of daunorubicin biosynthesis: one coding for the aklavinone C-11 hydroxylase and the other corresponding to the putative dnrR2 regulatory gene of wild-type S. peucetius ATCC 29050 (K. J. Stutzman-Engwall, S. L. Otten, and C. R. Hutchinson, J. Bacteriol. 174:144-154, 1992). Northern (RNA) blot experiments, performed with a ric1 fragment containing daunorubicin-doxorubicin resistance gene(s), revealed a transcript of about 2,100 nucleotides that is present only during the phase of anthracycline metabolite production. The amount of this transcript is higher in strain 7600 than in strain 7900, a mutant which produces 5-fold more daunorubicin and 10-fold less doxorubicin than 7600. Furthermore, two 7900-derived blocked mutants, 8600 and 9700, do not express the 2,100-nucleotide transcript in spite of the absence of gross rearrangements in the ric1 region such as occur with the 7900 parental strain.

Presence of transcription signals in two putative DNA replication origins of human cells

We describe the purification and cloning of human DNA replicated at the onset of S phase in HL60 cells synchronized with aphidicolin. A survey of the overall structural properties of these sequences did not show any distinctive features except for an enrichment in Cot0 DNA. The two longer fragments were completely sequenced and studied in more detail. Both were shown to contain transcriptional signals associated with promoters and/or enhancers, such as the binding sites of Sp1, T antigen and nuclear factor III. In one instance, a binding site for a known cellular transcription factor (USF/MLTF) was located inside the sequence by footprinting. Accordingly, by CAT assay and Northern blot, the same sequence was shown to contain an active promoter. The significance of these findings with respect to the role of transcription in initiation of DNA replication at the origin is discussed. None of the tested fragments exhibited autonomously replicating sequence (ARS) activity in transfected cells. The problems connected with the detection of ARS activity in human cells are critically examined.