Effects of sildenafil (Viagra) administration on seminal parameters and post-ejaculatory refractory time in normal males

Sildenafil is a specific inhibitor of phosphodiesterase (PDE) type 5 and represents a powerful therapy for male erectile dysfunction (ED) of different aetiology. Recently, sildenafil has been shown to restore erections in temporary ED related to the need of semen collection for assisted reproductive techniques. In this study, we investigated whether sildenafil administration modifies seminal parameters and/or erectile function in normal healthy volunteers. In a double-blind, randomized, placebo-controlled, cross-over two period investigation we enrolled 20 healthy male volunteers (mean +/- SE age 32 +/- 0.5 years). Subjects were not using any medication for the 3 month period prior to the study and were engaged in a stable relationship with proven fertility. The effects of sildenafil (100 mg) on seminal parameters and erectile function after audiovisual sexual stimulation were evaluated by semen analysis and by colour-Duplex ultrasound (the Resistive Index) respectively. In all subjects, sildenafil caused no changes in seminal and erection parameters when compared to placebo. Interestingly, sildenafil administration led to a marked reduction of the post-ejaculatory refractory time (10.8 +/- 0.9 min versus 2.6 +/- 0.7 min for placebo and sildenafil respectively; P < 0.0001). These results indicate that in normal subjects acute sildenafil treatment does not modify semen characteristics and has a positive influence over the resumption of erections following ejaculation in the presence of a continuous erotic stimulus.     

A PCR-colorimetric microwell plate hybridization assay for detection of Mycobacterium tuberculosis and M. avium from culture samples and Ziehl-Neelsen-positive smears

Differentiation between Mycobacterium tuberculosis and M. avium is essential for the treatment of mycobacterial infections. We have developed an easy and rapid detection assay for the diagnosis of mycobacterial diseases. This is a PCR-hybridization assay based on selective amplification of a 16S rRNA gene sequence using pan-Mycobacterium primers followed by hybridization of the amplification products to biotinylated M. tuberculosis and M. avium-specific probes. A total of 55 mycobacterial isolates were tested. For all isolates, results concordant with those of conventional identification methods were obtained. Moreover, we developed a method for extraction of DNA from Ziehl-Neelsen-positive smears which allows the recovery of intact target DNA in our PCR-hybridization assay. Our method was able to confirm all culture results for 59 Ziehl-Neelsen-positive smears from clinical specimens (35 sputum, 11 lymph node biopsy, 6 stool, 4 pus, 2 urine, and 1 pericardial fluid specimens). These data suggest that our PCR-hybridization assay, which is simple to perform and less expensive than commercial probe methods, may be suitable for the identification of M. tuberculosis and M. avium. It could become a valuable alternative approach for the diagnosis of mycobacterial infections when applied directly to DNA extracted from Ziehl-Neelsen-positive smears as well.     

Recurrent "Flexispira rappini" bacteremia in an adult patient undergoing hemodialysis: case report

A blood culture from a 65-year-old febrile man undergoing hemodialysis revealed, 5 days after inoculation, an unusual gram-negative fusiform rod with darting motility. During another episode of fever 21 days later, this Campylobacter-like organism was again recovered from three blood cultures and subcultured under an H2-enriched microaerobic atmosphere. The organism was catalase negative and oxidase positive and hydrolyzed urea rapidly. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of whole-cell proteins was indistinguishable from that of "Flexispira rappini" LMG 8738 described by Archer et al. in 1988 (J. R. Archer, S. Romero, A. E. Ritchier, M. E. Hamacher, B. M. Steiner, J. H. Bryner, and R. F. Schell, J. Clin. Microbiol. 26:101-105, 1988). The analysis of the 16S ribosomal DNA sequence revealed a similarity of 99.3% between the two strains. The patient recovered completely after a 4-week course of meropenem therapy. This is the first reported case of a recurrent "F. rappini" bacteremia in an adult patient, which confirms that this organism may be an invasive pathogen in immunocompromised patients, like other newly described Helicobacter species.     

Fusion of respiration-correlated PET and CT scans: correlated lung tumour motion in anatomical and functional scans

Lower lobe lung tumours in particular can move up to 2 cm in the cranio-caudal direction during the respiration cycle. This breathing motion causes image artefacts in conventional free-breathing computed tomography (CT) and positron emission tomography (PET) scanning, rendering delineation of structures for radiotherapy inaccurate. The purpose of this study was to develop a method for four-dimensional (4D) respiration-correlated (RC) acquisition of both CT and PET scans and to develop a framework to fuse these modalities. The breathing signal was acquired using a thermometer in the breathing airflow of the patient. Using this breathing signal, the acquired CT and PET data were grouped to the corresponding respiratory phases, thereby obtaining 4D CT and PET scans. Tumour motion curves were assessed in both image modalities. From these tumour motion curves, the deviation with respect to the mean tumour position was calculated for each phase. The absolute position of the centre of the tumour, relative to the bony anatomy, in the RCCT and gated PET scans was determined. This 4D acquisition and 4D fusion methodology was performed for five patients with lower lobe tumours. The peak-to-peak amplitude range in this sample group was 1-2 cm. The 3D tumour motion curve differed less than 1 mm between PET and CT for all phases. The mean difference in amplitude was less than 1 mm. The position of the centre of the tumour (relative to the bony anatomy) in the RCCT and gated PET scan was similar (difference <1 mm) when no atelectasis was present. Based on these results, we conclude that the method described in this study allows for accurate quantification of tumour motion in CT and PET scans and yields accurate respiration-correlated 4D anatomical and functional information on the tumour region.     

A nucleolar localizing Rev binding element inhibits HIV replication

The Rev protein of the human immunodeficiency virus (HIV) facilitates the nuclear export of intron containing viral mRNAs allowing formation of infectious virions. Rev traffics through the nucleolus and shuttles between the nucleus and cytoplasm. Rev multimerization and interaction with the export protein CRM1 takes place in the nucleolus. To test the importance of Rev nucleolar trafficking in the HIV-1 replication cycle, we created a nucleolar localizing Rev Response Element (RRE) decoy and tested this for its anti-HIV activity. The RRE decoy provided marked inhibition of HIV-1 replication in both the CEM T-cell line and in primary CD34+ derived monocytes. These results demonstrate that titration of Rev in the nucleolus impairs HIV-1 replication and supports a functional role for Rev trafficking in this sub-cellular compartment.     

Chromosomal assignment of human O6-methylguanine-DNA-methyltransferase gene by hamster-human somatic cell hybrids.

Using an in vitro assay to measure O6-methylguanine-DNA-methyltransferase (MT) activity in cell extracts from a panel of human-hamster cell hybrids, we were able to locate the human MT gene on chromosome 10. Chinese hamster cells have little or no MT activity and the presence of human chromosome 10 was a necessary condition for MT activity in cell hybrids. In some cell hybrids carrying chromosome 10, however, MT activity was not higher than that of hamster cells. As an explanation for this result, genetic determinants repressing MT expression and/or activity might be present in other human chromosomes carried by MT-negative cell hybrids. Partial hyperploidy of the hamster karyotype, variable activity of the parental human cell lines and changes during subculturing of the cell hybrids might also account for the lack of enzymatic activity in chromosome 10 containing hybrids.     

Antibody-dependent cellular cytotoxicity and neutralizing activity in sera of HIV-1-infected mothers and their children.

The prognostic and protective role of antibodies mediating cellular cytotoxicity (ADCC) and neutralization was evaluated in sera of HIV-1-infected mothers and their consecutively followed children. The presence and titres of ADCC mediating and/or neutralizing antibodies in maternal sera did not predict HIV-1 infection in their respective children. No significant difference in the sera from the children was seen when comparing the presence of neutralizing antibodies between the uninfected and infected children. Stratification of the infected group according to clinical status revealed differences. Only one of 24 AIDS patients had a high neutralizing titre against IIIB. Four patients had a very low titre and the remaining had no detectable neutralizing antibodies at all. In contrast, 10/17 infected non-AIDS children had neutralizing antibodies. Similarly, no significant difference was seen when comparing the presence of ADCC-mediating antibodies between the uninfected and the infected group of children. However, a significantly higher frequency of ADCC was seen in the seropositive non-AIDS children compared with the AIDS children. This study clearly shows that the presence of antibodies mediating ADCC and neutralization in infected children, 0-2 years old, is associated with a better clinical status and delayed disease progression.     

Current epidemiological and clinical features meningitis in a northern Italian area

Objectives: To study etiological, epidemiological and clinical features of 97 cases of acute meningitis. Methods: Ninety-seven cases of acute meningitis were examined in adult HIV-negative patients admitted to the Infectious Diseases Unit of the Azienda Ospedale-Universita S. Anna in Ferrara. Demographic, etiological, epidemiological and clinical data were analyzed. Results: All cases were divided into two groups according to the macroscopic aspect of cerebrospinal fluid (CSF): purulent CSF (50 cases) or non-purulent CSF (47 cases). Purulent CSF meningitis more frequently affected male patients (64% vs 47%) and older patients (average 52 vs 44 years). The main epidemiological features in both groups were underlying bacterial diseases (i.e. otomastoiditis and/or sinusitis in 50% of pneumococcal meningitis) and iatrogenic immunodeficiency. From a clinical point of view the following alterations in the state of consciousness (stupor, confusion and coma) were most frequently found in purulent meningitis. The following non purulent forms of meningitis were diagnosed: 5 tubercular, 3 viral infections, 2 by Listeria monocytogenes, 1 by Entoameba histolytica, 1 by Cryptococcus neoformans and 35 (74,4%) unknown causes. Purulent meningitis were: 20 (40%) Streptococcus pneumoniae, 10 Neisseria meningitidis, 3 Staphylococcus aureus, 2 Escherichia coli, 1 Haemophilus influenzae and 1 Pseudomonas aeruginosa; 13 cases were unidentified. From 1989 to 1993 and from 1994-98 both groups of meningitis increased; respectively from 17 to 30 cases for non-purulent meningitis and from 18 to 32 cases for purulent meningitis. Meningitis due to Streptococcus pneumoniae increased from 27.7% to 46.8% during the period 1994-98. Conclusions: The study shows the high incidence of pneumococcal meningitis, during 1994-98, because a large number of patients with sinusitis and otomastoiditis were observed. The incidence of meningococcal meningitis appears stable. These data confirm the importance of timely diagnosis and correct therapy for such infections with reserved prognosis.