The variability of baroreflex sensitivity in juvenile, spontaneously hypertensive rats

In this study the baroreflex sensitivity of conscious, juvenile, spontaneously hypertensive rats (SHRs) was compared. The study population consisted of 19 eight-week-old male SHRs. The baroreflex sensitivity was quantified as the derivative of the variation in heart rate (HR) and the variation of mean arterial pressure (baroreflex sensitivity = ΔHR/ΔMAP). MAP was manipulated with sodium nitroprusside (SNP) and phenylephrine (PHE), administered via an inserted cannula in the right femoral vein. The SHRs were divided into four groups: (1) low bradycardic baroreflex (LB) where the baroreflex gain (BG) was between 0 and -1 bpm/mmHg with PHE; (2) high bradycardic baroreflex (HB), where the BG was < -1 bpm/mmHg with PHE; (3) low tachycardic baroreflex (LT) where the BG was between 0 and 3 bpm/mmHg with SNP; (4) high tachycardic baroreflex (HT) where the BG was > 3 bpm/mmHg with SNP. We noted that 36.8% of the rats presented with an increased bradycardic reflex, while 27.8% demonstrated an attenuated tachycardic reflex. No significant alterations were noted regarding the basal MAP and HR. There were significant differences in the baroreflex sensitivity between SHRs in the same laboratory. One should be careful when interpreting studies employing the SHR as a research model.

Structure and functional significance of the transverse vesical fold

The plica vesicalis transversa or transverse vesical fold (TVF) is a peritoneal fold extending from the lateral side of the bladder to the side of the lesser pelvis near the deep inguinal ring. It is an important landmark in laparoscopic surgery of the pelvis but is variably observed in the embalmed cadaver. We investigated the gross anatomy of this structure in the cadaver and confirmed that its medial portion corresponds to the location of the superior vesical artery(ies), thus supporting the idea that the TVF is "mesovesical." However, no large vessels were observed grossly in the lateral portion of the TVF. The hypothesis that the lateral TVF has a suspensory function was tested histologically by comparison with the suspensory ligament of the duodenum and the phrenicocolic ligament, both of which have smooth muscle contributing to their inferred suspensory function. Microscopic examination of prepared samples from 20 cadavers shows that the TVF evinces no smooth muscle in either its lateral or medial segments. The TVF is demonstrated to be a mesentery-like reflection of peritoneum raised by branches of the superior vesical artery which provides no demonstrable structural support for the bladder. Implications of these findings include avoidance of sectioning of medial TVF during laparoscopic surgery because of its vascular nature, and inadvisability of utilizing any portion of theTVF for an anchor in reconstruction of the anterior pelvic floor within the paravesical fossae.

[Cervical disease in postmenopausal HIV-1-infected women]

INTRODUCTION

An increasing number of HIV-1-infected women reaches the age of menopause. This infection is associated with a higher incidence of cervical squamous intraepithelial lesions (low-grade or LSIL, high grade or HSIL). The aim of our study was to describe the cervical disease in these patients during menopause.

PATIENTS AND METHODS

Retrospective study, identifying all Pap smears and colposcopy in HIV-1-infected postmenopausal women between 1995 and 2008, in our hospital.

RESULTS

Eighteen postmenopausal women, aged of 54 years (43-63), have HIV-1 infection since 7.5 years (2-25). Fifty-one pathological exams were reviewed in which 27 (50.98%) abnormal, including four (7.84%) ASC-US, 15 (29.41%) LSIL lesions, and seven (13.73%) HSIL. Ten patients had surgery (laser, conisation, hysterectomy) during the period. The evolution of cervical lesions was: stability in 40.48%, regression in 35.71% and progression in 23.81%. The median time to develop an HSIL at menopause was 5 years.

CONCLUSION

In our study, postmenopausal HIV-1-infected women have most frequently LSIL and persistent. Monitoring of these postmenopausal women should be continued, the attitude to realise an initial HPV typing and confirmation of an abnormal annually Pap smear with colposcopic exam should be confirmed by larger study.

Etiology of bronchiolitis in a hospitalized pediatric population: prospective multicenter study

Background

In 2006, bronchiolitis due to adenovirus nosocomial infections resulted in the closure of a pediatric department in northern Portugal.

Objectives

To determine the etiology of bronchiolitis in northern Portugal.

Study design

It was a prospective multicenter study on the etiology of bronchiolitis during the respiratory syncytial virus (RSV) season (November–April). Children ≤24 months of age admitted for a first wheezing episode were included. Nasopharyngeal specimens were analyzed by an indirect immunofluorescent-antibody assay (IFA) for RSV, adenovirus (HAdV), parainfluenza (PIV) 1–3 and influenza (IV) A and B and by polymerase chain reaction (PCR) or reverse transcription-PCR for the same viruses and for human metapneumovirus (hMPV), bocavirus (HBoV), rhinovirus (HRV), coronaviruses (229/E; NL63; OC43; HKU1) and enterovirus.

Results

During this period, 253 children were included, 249 IFA analyses and 207 PCRs were performed. IFA detected RSV in 58.1%; PCR increased it to 66.7%. IFA detected HAdV in 3.2%, PCR 10.0%. PCR detected IV A in 5; IV B in 2; PIV 1 in 6, PIV 2 in 4 and PIV 3 in 11 cases. HBoV, as single agent in 2 cases, and HRV were positive in 8 samples and hMPV in 11. With this virus panel, 19.7% remained without etiology.

Conclusions

The most frequent agent was RSV, followed by HAdV. PCR can be cost-effective and more accurate than IFA, which is crucial for HAdV that may be associated with significant mortality (IFA alone did not detect 2/3 of the cases).

Biofouling control using microparticles carrying a biocide

This study presents a new technological approach to minimize the use of antimicrobial (AMB) agents and their deleterious effects, based on the principle of drug-delivery systems whereby the AMB chemicals are transported on microparticles. The efficacy of microparticles carrying the quaternary ammonium compound (QAC), benzyldimethyldodecyl ammonium chloride (BDMDAC), was assessed against Pseudomonas fluorescens in both the planktonic and the biofilm state. The microparticles were prepared using a layer-by-layer (LBL) self-assembly technique. Oppositely charged molecules of polyethyleneimine (PEI), sodium polystyrene sulfonate (PSS), and BDMDAC were assembled on polystyrene (PS) cores. BDMDAC-coated particles were observed by CryoSEM and their composition analyzed by X-ray microanalysis. Zeta potential measurements indicated that changes in surface charge were compatible with a BDMDAC/particle interaction. This biocidal carrier structure had significant stability, verified by the release of only 15% of the BDMDAC when immersed in water for 18 months. Biocidal carrier activity was evaluated by determining the survival ratio of P. fluorescens planktonic and biofilm cells after different exposure periods to BDMDAC-coated particles. Tests with biofilm cells were also performed with the free QAC. An efficient AMB effect (minimum bactericidal concentration) against suspended cells was found for a concentration of 9.2 mg l(-1) of BDMDAC on coated particles after incubation for 30 min and 6.5 mg l(-1) of BDMDAC on coated particles after 60 min. Exposure of biofilms to PS-PEI/PSS/BDMDAC (0.87 mg l(-1)) resulted in a decrease in viability of 60.5% and 66.5% of the total biofilm population for 30 and 60 min exposure times, respectively. Exposure for 60 min to 6.33 mg l(-1) and 11.75 mg l(-1) of BDMDAC in PS-PEI/PSS/BDMDAC particles promoted inactivation of 80.6% and 87.2% of the total population, respectively. The AMB effects obtained with the application of free BDMDAC were statistically similar to those promoted by the application of BDMDAC coated particles. The overall results indicate that this novel AMB strategy has potential for the control of microbial growth of planktonic cells and biofouling. Moreover, the technique allows the reuse of AMB molecules and consequently reduces the environmental risks associated with excessive use of AMB agents, thereby providing real benefits to public health.

Sequencing of Spodoptera frugiperda midgut trehalases and demonstration of secretion of soluble trehalase by midgut columnar cells

Both soluble (SfTre1) and membrane-bound (SfTre2) trehalases occur along the midgut of Spodoptera frugiperda larvae. Released SfTre2 was purified as a 67 kDa protein. Its K(m) (1.6 mM) and thermal stability (half life 10 min at 62 degrees C) are different from the previously isolated soluble trehalase (K(m)= 0.47 mM; 100% stable at 62 degrees C). Two cDNAs coding for S. frugiperda trehalases have been cloned using primers based on consensus sequences of trehalases and having as templates a cDNA library prepared from total polyA-containing RNA extracted from midguts. One cDNA codes for a trehalase that has a predicted transmembrane sequence and was defined as SfTre2. The other, after being cloned and expressed, results in a recombinant trehalase with a K(m) value and thermal stability like those of native soluble trehalase. This enzyme was defined as SfTre1 and, after it was used to generate antibodies, it was immunolocalized at the secretory vesicles and at the glycocalyx of columnar cells. Escherichia coli trehalase 3D structure and sequence alignment with SfTre1 support a proposal regarding the residue modulating the pKa value of the proton donor.

The Aedes aegypti larval transcriptome: a comparative perspective with emphasis on trypsins and the domain structure of peritrophins

The genome sequence of Aedes aegypti was recently reported. A significant amount of Expressed Sequence Tags (ESTs) were sequenced to aid in the gene prediction process. In the present work we describe an integrated analysis of the genomic and EST data, focusing on genes with preferential expression in larvae (LG), adults (AG) and in both stages (SG). A total of 913 genes (5.4% of the transcript complement) are LG, including ion transporters and cuticle proteins that are important for ion homeostasis and defense. From a starting set of 245 genes encoding the trypsin domain, we identified 66 putative LG, AG, and SG trypsins by manual curation. Phylogenetic analyses showed that AG trypsins are divergent from their larval counterparts (LG), grouping with blood-induced trypsins from Anopheles gambiae and Simulium vittatum. These results support the hypothesis that blood-feeding arose only once, in the ancestral Culicomorpha. Peritrophins are proteins that interlock chitin fibrils to form the peritrophic membrane (PM) that compartmentalizes the food in the midgut. These proteins are recognized by having chitin-binding domains with 6 conserved Cys and may also present mucin-like domains (regions expected to be highly O-glycosylated). PM may be formed by a ring of cells (type 2, seen in Ae. aegypti larvae and Drosophila melanogaster) or by most midgut cells (type 1, found in Ae. aegypti adult and Tribolium castaneum). LG and D. melanogaster peritrophins have more complex domain structures than AG and T. castaneum peritrophins. Furthermore, mucin-like domains of peritrophins from T. castaneum (feeding on rough food) are lengthier than those of adult Ae. aegypti (blood-feeding). This suggests, for the first time, that type 1 and type 2 PM may have variable molecular architectures determined by different peritrophins and/or ancillary proteins, which may be partly modulated by diet.

Intravascular pulmonary lymphoma with good response to treatment. A case report

Intravascular lymphoma is a very rare form of large B cell non-Hodgkin's lymphoma, characterised by the presence of lymphoma cells in the lumina of small vessels only, particularly in the capillaries. We report a 54 year-old female non-smoker, admitted to hospital for further examination of a four month long clinical condition involving high fever, night sweats, unqualified weight loss and progressive dyspnea. Patient's temperature was 38.5 degrees C, pulse 100/min and respiratory 22 cycles/min. Patient's haemoglobin was 9.4 g/dL, she had leukocytosis, elevated LDH and arterial blood gas analysis with moderate hypoxaemia (FiO2 1l/m: PaO2-63.6 mm Hg). Chest X-ray revealed diffuse interstitial changes. All the possible causes of unknown origin fever were excluded. Diagnosis was made through lung biopsy and treatment with combined chemotherapy and rituximab was prescribed leading to a 48 hours clinical remission. We present this case to show how difficult this diagnosis can be and how a good response to therapy is possible.

Steroids augment relengthening of contracted airway smooth muscle: potential additional mechanism of benefit in asthma

Breathing (especially deep breathing) antagonises development and persistence of airflow obstruction during bronchoconstrictor stimulation. Force fluctuations imposed on contracted airway smooth muscle (ASM) in vitro result in its relengthening, a phenomenon called force fluctuation-induced relengthening (FFIR). Because breathing imposes similar force fluctuations on contracted ASM within intact lungs, FFIR represents a likely mechanism by which breathing antagonises bronchoconstriction. While this bronchoprotective effect appears to be impaired in asthma, corticosteroid treatment can restore the ability of deep breaths to reverse artificially induced bronchoconstriction in asthmatic subjects. It has previously been demonstrated that FFIR is physiologically regulated through the p38 mitogen-activated protein kinase (MAPK) signalling pathway. While the beneficial effects of corticosteroids have been attributed to suppression of airway inflammation, the current authors hypothesised that alternatively they might exert their action directly on ASM by augmenting FFIR as a result of inhibiting p38 MAPK signalling. This possibility was tested in the present study by measuring relengthening in contracted canine tracheal smooth muscle (TSM) strips. The results indicate that dexamethasone treatment significantly augmented FFIR of contracted canine TSM. Canine tracheal ASM cells treated with dexamethasone demonstrated increased MAPK phosphatase-1 expression and decreased p38 MAPK activity, as reflected in reduced phosphorylation of the p38 MAPK downstream target, heat shock protein 27. These results suggest that corticosteroids may exert part of their therapeutic effect through direct action on airway smooth muscle, by decreasing p38 mitogen-activated protein kinase activity and thus increasing force fluctuation-induced relengthening.