Rapid signal transduction in Sertoli cells

The importance of non-genomic signaling as a complementary route for cell regulation has recently become evident. This rapid mechanism is utilized not just by peptide hormones, but also by steroids and other lipid-related substances, resulting in amplification and fine-tuning of the signals. The Sertoli cell is the principal target for hormone action in the seminiferous tubules. The involvement of FSH, testosterone and tri-iodothyronine (T(3)) in the spermatogenetic process is widely known. This paper discusses some rapid responses to FSH, retinol, testosterone and T(3) in the control of Sertoli cell function. Studies employing various methodologies and techniques are described and several hypotheses are considered in an attempt to explain the interactions of hormones with plasma membrane receptors. Recent knowledge about these new signaling mechanisms and cross-talk between them opens new fields of research on the communication and integration of the multiple hormonal signaling systems.

Insulinomimetic effect of kaempferol 3-neohesperidoside on the rat soleus muscle

A stimulatory effect of kaempferol 3-neohesperidoside ( 1) on glucose uptake (35% and 21%) was observed when the rat soleus muscle was incubated with 1 and 100 nM of this flavonoid glycoside, respectively. The concentration-response curve of insulin showed a stimulatory effect at 3.5 and 7.0 nM (42% and 50%) on glucose uptake when compared with the control group. The effect of 1 on glucose uptake was completely nullified by pretreatment with LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K), and RO318220, an inhibitor of protein kinase C (PKC). However, no significant change occurred on glucose uptake stimulated by 1 when muscles were pretreated with PD98059, an inhibitor of mitogen-activated protein kinase (MEK), and cycloheximide, an inhibitor of protein synthesis. Compound 1 and insulin (7 nM) did not show a synergistic effect on glucose uptake. Additionally, 100 mg/kg of 1 by oral gavage was able to increase glycogen content in the muscle. These results suggest that 1 stimulates glucose uptake in the rat soleus muscle via the PI3K and PKC pathways and, at least in part, independently of MEK pathways and the synthesis of new glucose transporters.

Co-selection of antibiotic and metal(loid) resistance in gram-negative epiphytic bacteria from contaminated salt marshes

The goal of this study was to investigate co-selection of antibiotic resistance in gram-negative epiphytic bacteria. Halimione portulacoides samples were collected from metal(loid)-contaminated and non-contaminated salt marshes. Bacterial isolates (n=137) affiliated with Vibrio, Pseudomonas, Shewanella, Comamonas, Aeromonas and with Enterobacteriaceae. Vibrio isolates were more frequent in control site while Pseudomonas was common in contaminated sites. Metal(loid) and antibiotic resistance phenotypes varied significantly according to site contamination, and multiresistance was more frequent in contaminated sites. However, differences among sites were not observed in terms of prevalence or diversity of acquired antibiotic resistance genes, integrons and plasmids. Gene merA, encoding mercury resistance, was only detected in isolates from contaminated sites, most of which were multiresistant to antibiotics. Results indicate that metal(loid) contamination selects for antibiotic resistance in plant surfaces. In salt marshes, antibiotic resistance may be subsequently transferred to other environmental compartments, such as estuarine water or animals, with potential human health risks.

Our PDT experience in the treatment of non-melanoma skin cancer over the last 7 years

BACKGROUND

Topical photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) was first described by Kennedy et al. in 1990; currently, accumulated evidence shows that topical PDT is effective in the treatment of actinic keratoses, Bowen's disease and superficial basal cell carcinoma, being potentially advantageous where size, anatomical location or number of lesions limit the efficacy and/or the acceptability of conventional therapies. It involves the use of photosensitizing drugs and the administration of an appropriate light source to activate the sensitizing agent, which leads to the production of activated oxygen species for tissue destruction. The topically administered prodrug 5-ALA is converted within cells into the active photosensitizer protoporphyrin IX, via haem cycle, with preferential accumulation in tumour cells.

METHODS

The authors describe their experience with topical PDT, using 20% 5-ALA and two different incoherent light sources, 'Waldman 1200 L' and 'VersaLight', in the treatment of non-melanoma skin cancer and precursor lesions. More than 100 patients were treated since 1997, with up to a 7-year follow-up period.

RESULTS

Cases are illustrated and results are presented and discussed in the light of the relevant Literature.

CONCLUSION

The study suggests that 5-ALA PDT is effective in the treatment of superficial skin cancer and premalignant lesions.

Effect of 3,5,3'-triiodo-L-thyronine on amino acid accumulation and membrane potential in Sertoli cells of the rat testis

The purpose of this study was to investigate the effect of T3 on amino acid accumulation and on the membrane potential of Sertoli cells of immature rat testes. Testes of pre-pubertal and pubertal rats were pre-incubated (30 min) in Krebs-Ringer bicarbonate buffer and incubated in the presence of [14C]methylaminoisobutyric acid with and without T3 for 15, 45 and 60 min. The hormone (10(-6) M and 10(-7) M) significantly stimulated amino acid accumulation in 6 and 13-day old rat testes but did not have any effect in neonatal and pubertal animals. T3 produced a dose-dependent hyperpolarizing effect at concentrations of 10(-6) M, 10(-5) M, 2 x 10(-5) M and 10(-4) M. We conclude that T3 induces a membrane hyperpolarization in Sertoli cells and stimulates amino acid accumulation in immature rat testes, demonstrating that the hormone has a rapid plasma membrane action.

Role of 1alpha,25(OH)2 vitamin D3 on alpha-[1-(14)C]MeAIB accumulation in immature rat testis

1,25D3 is critical for the maintenance of normal reproduction since reduced fertility is observed in male rats on a vitamin D-deficient diet. Vitamin D-deficient male rats have incomplete spermatogenesis and degenerative testicular changes. In the present study we have examined the ionic involvement and intracellular messengers of the stimulatory effect of 1,25D3 on amino acid accumulation in immature rat testis. 1,25D3 stimulates amino acid accumulation from 10(-12) to 10(-6) M by increasing the slope to reach a maximum value at 10(-10) M, as compared to the control group. No effect was observed at a lower dose (10(-13) M). Time-course showed an increase on amino acid accumulation after 15, 30, and 60 min of incubation with 1,25D3 (10(-10) M). 1,25D3 stimulated amino acid accumulation in 11-day-old rat testis but not in testis that were 20 days old. Cycloheximide totally blocked the 1,25D3 action on amino acid accumulation. Furthermore, a localized elevation of cAMP increased the stimulatory effect of 1,25D3 and the blockage of PKA nullified the action of the hormone. In addition, 1,25D3 action on amino acid accumulation was also mediated by ionic pathways, since verapamil and apamine diminished the hormone effect. The stimulatory effect of 1,25D3 on amino acid accumulation is age-dependent and specific to this steroidal hormone since testosterone was not able to change amino acid accumulation in both ages studied. This study provides evidence for a dual effect for 1,25D3, pointing to a genomic effect that can be triggered by PKA, as well as to a rapid response involving Ca2+/K+ channels on the plasma membrane.

Rapid responses to thyroxine in the testis: active protein synthesis-independent pathway

We investigated the involvement of protein synthesis in the stimulatory action of thyroid hormones on amino acid accumulation and characterized K(+) currents involved in the hyperpolarizing effect of thyroxine (T(4)) on Sertoli cells. Immature rat testes were incubated in Krebs Ringer-bicarbonate buffer (KRb) in the presence of [(14)C]methylaminoisobutyric acid with and without T(4), 3,5,3'-l-triiodothyronine (T(3)) and/or cycloheximide. Sertoli cells were monitored by intracellular recording in a chamber perfused with KRb with and without T(4), T(3) and/or blockers, and the membrane potential was monitored. T(4) and T(3) stimulated amino acid accumulation and protein synthesis. Treatment with cycloheximide diminished T(3) stimulatory actions on amino acid accumulation but had no effect on T(4) action. Both hormones elicited a hyperpolarization of the Sertoli cell membrane potential which involved K(+) channels, since TEA and apamin abolished this effect. These findings on rapid membrane actions of thyroid hormone in the testis suggest that some effects of T(4) are modulated by non-genomic mechanisms.

Adenosquamous carcinoma in Barrett's esophagus presenting as pseudoachalasia

A case of pseudoachalasia resulting from adenosquamous carcinoma arising from the mucous epithelium of a Barrett's esophagus is presented. This case represents an unusual combination of Barrett's esophagus giving rise to an esophageal carcinoma with squamous as well as glandular features, rather than the usual adenocarcinoma and pseudoachalasia.

Phylogenetic diversity and functional characterization of the Manila clam microbiota: a culture-based approach

According to the hologenome theory, the microbiota contributes to the fitness of the holobiont having an important role in its adaptation, survival, development, health, and evolution. Environmental stress also affects the microbiota and its capability to assist the holobiont in coping with stress factors. Here, we analyzed the diversity of cultivable bacteria associated with Manila clam tissues (mantle, gills, hemolymph) in two non-contaminated sites (Portugal and France) and one metal-contaminated site (Portugal). A total of 240 isolates were obtained. Representative isolates (n = 198) of the overall diversity were identified by 16S rDNA sequencing and subjected to functional characterization. Isolates affiliated with Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Proteobacteria (mostly Pseudoalteromonadaceae and Vibrionaceae) were dominant in non-contaminated sites while Actinobacteria (mostly Microbacteriaceae) dominated in the metal-contaminated site. The main factor affecting the microbiota composition was contamination. No significant differences were observed between clam tissues and geographic regions. Several isolates tested positive for antibacterial activity, biofilm formation, protease, and siderophore production. The results show that the Manila clam harbors a diverse microbiota that may contribute to clam protection and overall fitness, as well as to its adaptation to stressful environments. In addition, the Manila clam microbiota is revealed as a promising source of novel probiotics with potential application in aquaculture.

Theoretical and experimental analysis of electroporated membrane conductance in cell suspension

An intense electric field can be applied to increase the membrane conductance G(m) and consequently, the conductivity of cell suspension. This phenomenon is called electroporation. This mechanism is used in a wide range of medical applications, genetic engineering, and therapies. Conductivity measurements of cell suspensions were carried out during application of electric fields from 40 to 165 kV/m. Experimental results were analyzed with two electroporation models: the asymptotic electroporation model was used to estimate G(m) at the beginning and at the end of electric field pulse, and the extended Kinosita electroporation model to increase G(m) linearly in time. The maximum G(m) was 1-7 × 10(4) S/m(2), and the critical angle (when the G(m) is insignificant) was 50°-65°. In addition, the sensitivity of electroporated membrane conductance to extracellular and cytoplasmatic conductivity and cell radius has been studied. This study showed that external conductivity and cell radius are important parameters affecting the pore-opening phenomenon. However, if the cell radius is larger than 7 μm in low conductivity medium, the cell dimensions are not so important.

Unilateral nevoid telangiectasia: a rare disease?

Unilateral nevoid telangiectasia is a rare congenital or acquired disorder. The majority of the authors propose that it is probably related to elevated estrogen receptors, although other authors advocate different theories. We report the occurrence of lesions clinically compatible with this diagnosis in a child and two adults. Only one of the patients had a background of estrogen elevation. The other two patients were healthy. We stress the occurrence of this disease in a rare idiopathic form and point out to the relative elevated incidence of it, because the patients discussed in this article were observed for a short period of time.

The ESC ACCA EAPCI EORP acute coronary syndrome ST-elevation myocardial infarction registry

Aims 

The Acute Cardiac Care Association (ACCA)–European Association of Percutaneous Coronary Intervention (EAPCI) Registry on ST-elevation myocardial infarction (STEMI) of the EurObservational programme (EORP) of the European Society of Cardiology (ESC) registry aimed to determine the current state of the use of reperfusion therapy in ESC member and ESC affiliated countries and the adherence to ESC STEMI guidelines in patients with STEMI.

Methods and results 

Between 1 January 2015 and 31 March 2018, a total of 11 462 patients admitted with an initial diagnosis of STEMI according to the 2012 ESC STEMI guidelines were enrolled. Individual patient data were collected across 196 centres and 29 countries. Among the centres, there were 136 percutaneous coronary intervention centres and 91 with cardiac surgery on-site. The majority of centres (129/196) were part of a STEMI network. The main objective of this study was to describe the demographic, clinical, and angiographic characteristics of patients with STEMI. Other objectives include to assess management patterns and in particular the current use of reperfusion therapies and to evaluate how recommendations of most recent STEMI European guidelines regarding reperfusion therapies and adjunctive pharmacological and non-pharmacological treatments are adopted in clinical practice and how their application can impact on patients’ outcomes. Patients will be followed for 1 year after admission.

Conclusion 

The ESC ACCA-EAPCI EORP ACS STEMI registry is an international registry of care and outcomes of patients hospitalized with STEMI. It will provide insights into the contemporary patient profile, management patterns, and 1-year outcome of patients with STEMI.

Maturation and long-term hypoxia alters Ca2+-induced Ca2+ release in sheep cerebrovascular sympathetic neurons

The contribution of sympathetic nerves arising from the superior cervical ganglia (SCG) toward the growth and function of cerebral blood vessels is pertinent throughout maturation as well as in response to cardiovascular stress imposed by high-altitude long-term hypoxia (LTH). The function of SCG sympathetic neurons is dependent on intracellular Ca2+ concentration ([Ca2+]i) signaling, which is strongly influenced by a process known as Ca(2+)-induced Ca2+ release (CICR) from the smooth endoplasmic reticulum (SER). In this study, we used the sheep SCG neuronal model to test the hypotheses that maturation decreases CICR and high-altitude LTH depresses CICR in fetal SCG neurons but not in those of the adult. We found that the contribution of CICR to electric field stimulation (EFS)-evoked [Ca2+]i transients was greatest in SCG cells from normoxic fetuses and was abolished by LTH. The decline in CICR was associated with a reduction in sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) function in fetal SCG cells during LTH, reducing SER Ca2+ levels below the threshold needed for the coupling of Ca2+ influx and CICR. With respect to the maturation from the fetus to adult, the decrease in CICR may reflect both a reduction in the levels of ryanodine receptor isoforms 2 and 3 and SERCA function. In response to LTH and in contrast to the fetus, CICR function in adult SCG cells is maintained and may reflect alterations in other mechanisms that modulate the CICR process. As CICR is instrumental in the function of sympathetic neurons within the cerebrovasculature, the loss of this signaling mechanism in the fetus may have consequences for the adaptation to LTH in terms of fetal susceptibility to vascular insults.

Species Identification and Resistance Status of Anopheles gambiae s.l. (Diptera: Culicidae) Mosquitoes in Guinea

Insecticide resistance is one of the primary threats to the recent gains in malaria control. This is especially true in Guinea, where long-lasting insecticidal nets are currently the primary vector control intervention. To better inform the national malaria control program on the current status of insecticide resistance in Guinea, resistance bioassays were conducted, using Anopheles gambiae s.l. Giles, in three sites. Molecular analyses were also done on An. gambiae s.l. to determine the species and find whether the target-site mutations kdr and Ace1R were present. Susceptibility tests revealed resistance to DDT and pyrethroids, although mosquitoes were susceptible to deltamethrin in two of the three sites tested. Mosquitoes were susceptible to bendiocarb, except in Kissidougou, Guinea. The kdr-west mutation was widespread and the frequency was 60% or more in all sites. However, the Ace1R mutation was present in low levels. Insecticide susceptibility should continue to be monitored in Guinea to ensure insecticide-based vector control methods remain effective.

Zinc pharmacokinetic parameters in the determination of body zinc status in children

BACKGROUND/OBJECTIVES

Serum or tissue zinc concentrations are often used to assess body zinc status. However, all of these methods are relatively inaccurate. Thus, we investigated three different kinetic methods for the determination of zinc clearance to establish which of these could detect small changes in the body zinc status of children.

SUBJECTS/METHODS

Forty apparently healthy children were studied. Renal handling of zinc was investigated during intravenous zinc administration (0.06537 mg Zn/kg of body weight), both before and after oral zinc supplementation (5 mg Zn/day for 3 months). Three kinetic methods were used to determine zinc clearance: CZn-Formula A and CZn-Formula B were both used to calculate systemic clearance; the first is a general formula and the second is used for the specific analysis of a single-compartment model; CZn-Formula C is widely used in medical practices to analyze kinetic routine.

RESULTS

Basal serum zinc values, which were within the reference range for healthy children, increased significantly after oral zinc supplementation. The three formulas used gave different results for zinc clearance both before and after oral zinc supplementation. CZn-Formula B showed a positive correlation with basal serum zinc concentration after oral supplementation (R2=0.1172, P=0.0306). In addition, CZn-Formula B (P=0.0002) was more effective than CZn-Formula A (P=0.6028) and CZn-Formula C (P=0.0732) in detecting small variations in body zinc status.

CONCLUSIONS

All three of the formulas used are suitable for studying zinc kinetics; however, CZn-Formula B is particularly effective at detecting small changes in body zinc status in healthy children.

Evaluation of off-axis projection geometry in dental panoramic radiography

New electronic imaging capabilities afforded by the use of linear charged-couple device arrays allow acquisition of three-dimensional information through simultaneous recordings from multiple sensors situated at different fixed angles. In theory, the resulting data can be processed to yield images tailored to specific diagnostic tasks that can be produced and manipulated on demand after exposure. The first step to determine the practical potential of such a system in panoramic radiography is to demonstrate the degree to which specific changes in projection geometry can be used to improve performance of selected diagnostic tasks of clinical interest in dentistry. Hence, the purpose of this investigation was to explore the potential to reduce proximal overlap that exist in current panoramic radiographs and also to displace the blurred image of the spine from areas of diagnostic interest through the use of off-axis projection geometry of the slit beam of radiation. As the off-axis angulation increased, more embrasures in the different areas of the dental arches of skull specimens were opened; the effects of beam angulation in the number of open embrasures was statistically significant (ANOVA, p < 0.05). A hypothetical multibeam system significantly improved the projection geometry toward the creation of images that contain little, if any, proximal overlap when compared with the conventional bilaterally symmetrical projection geometry system (t test, p < 0.001). At 6 degrees off-axis projection angle, the system was able to clear completely the anterior area from the superimposing shadow of the spinal column. The results show that multibeam alternatives to the single beam projection can significantly improve diagnostic quality in panoramic radiographs.

A case-control study on the association of hepatitis B virus infection and hepatocellular carcinoma in northeast Brazil

Hepatitis B virus (HBV) serological markers were investigated in 40 incident cases of hepatocellular carcinoma (HCC) and in two age and sex matched control groups, comprising 40 patients with other cancers and 80 healthy individuals, resident in Bahia, Brazil. Serologic tests were done by radioimmunoassay. The study observed high proportion of seropositivity to HBsAg (42.5%) and of those presenting HBsAg or antiHBc (65.0%) among HCC cases, higher in men than women and in those aged 17 to 30 years old. HBsAg seropositivity among HCC patients was greater than in the control group with other cancers (7.5%) and in healthy controls (2.5%), corresponding to odds ratio estimates of 15.0 (95% CI 3.29, 68.30) and 33.0 (95% CI 9.13, 119.28), both statistically significant. HBeAg was not observed and antiHBe was present in 41.2% of cases, suggesting the absence of viral replication, possibly with viral DNA integration into the hepatocyte genome. The presence of cirrhosis was associated with HBsAg seropositivity among HCC cases. A history of chronic alcoholism is shown to be more frequently related to those cases with cirrhosis. This study highlights the relevant association between HCC and HBV in Northeast Brazil, particularly for young individuals, and the high risk of development of HCC for HBsAg carriers.