Pathological and vascular changes in the rat testiсle after experimental trauma.

Objective: Mechanical trauma to the testicles poses a potential risk of tissue destruction, disruption of local blood supply, and impairment of spermatogenesis, which can ultimately lead to infertility. Therefore, investigating this topic is crucial. The study aimed to identify cytological and morphological changes in the testicular tissue of laboratory rats following mechanical trauma to the organ. Methods: Observations were recorded on days 7, 14, 30, and 90 post-trauma. The experiment involved two groups of animals: a control group of healthy animals and an experimental group that sustained blunt mechanical trauma. Tissue samples were collected, fixed, dehydrated, and embedded in paraffin; subsequently, sections were prepared and stained. Structural changes in tissues and cells were documented using light and transmission electron microscopy. Results: In the experimental sample, notable changes included a decrease in organ weight, thickening of the protein shell and tubule walls, sclerotisation of the tubule membrane, narrowing of tubule diameter, reduced spermatozoa and spermatids titre, diminished capillary network and spermatogenic epithelium, uneven blood vessel lumen expansion, and decreased volume of Leydig cell nuclei. Additionally, in cells under different functional loads, the cytoplasm was vacuolated, mitochondrial cristae and the Golgi apparatus were diminished, cytoplasm volume decreased, karyopyknosis was observed, and uncharacteristic protrusions appeared on the surface of the cytoplasmic membrane. The severity of destruction at the cellular and tissue levels showed a positive correlation with time. Conclusion: The data obtained from these model sites can be predictive for clinical trials.

Paracellular barriers: Advances in assessing their contribution to renal epithelial function.

Regulation of salt and water balance occupies a dominant role in the physiology of many animals and often relies on the function of the renal system. In the mammalian kidney, epithelial ion and water transport requires high degree of coordination between the transcellular and paracellular pathways, the latter being defined by the intercellular tight junctions (TJs). TJs seal the paracellular pathway in a highly specialized manner, either by forming a barrier against the passage of solutes and/or water or by allowing the passage of ions and/or water through them. This functional TJ plasticity is now known to be provided by the members of the claudin family of tetraspan proteins. Unlike mammalian nephron, the renal structures of insects, the Malpighian tubules, lack TJs and instead have smooth septate junctions (sSJs) as paracellular barrier forming junctions. Many questions regarding the molecular and functional properties of sSJs remain open but research on model species have begun to inform our understanding. The goal of this commentary is to highlight key concepts and most recent findings that have emerged from the molecular and functional dissection of paracellular barriers in the mammalian and insect renal epithelia.

Ultrastructural changes in the spermatogenic cells of domestic chicken (Gallus gallus domesticus) observed at different reproductive stages.

Spermatogenesis is a complex process. It is the modification of progenitor spermatogonia into mature spermatozoa. The stages are similar in all-male vertebrates, as well as avian species. However, studies on spermatogenesis in birds are fewer compared to mammals. The current study investigated the ultrastructural changes in the spermatogenic cells of domestic chickens in different reproductive stages. Thirty (30) male birds, ten (10) in each of the three reproductive stages: pre-pubertal, pubertal, and adult were used in the study. Testicular tissues from all age groups were processed for transmission electron microscopy (TEM). TEM results showed spermatogonia and primary spermatocytes in the pre-pubertal testis, and the seminiferous tubule lumen was wide and empty. Also, the nuclei of spermatogonia at this stage did not contain condensed chromatin material at the center nor scattered at the periphery of the nuclear membrane. There were slight differences between the spermatogenic cells in the pubertal and adult age groups. The spermatogonia, primary and secondary spermatocytes, and round spermatids with scanty chromatin material were observed in both age groups. In the adult age group, round and elongated spermatids with condensed chromatin materials were observed besides the other spermatogenic cells. Also, the seminiferous tubule lumen was filled with sperm cells and cellular debris, unlike in the pre-pubertal and pubertal age groups where they were wide and empty. The presence of numerous oval mitochondria were observed in all age groups. This signifies the active process of spermatogenesis in pre-pubertal, pubertal, and adult male domestic chickens.

Untangling the Uncertain Role of Overactivation of the Renin-Angiotensin-Aldosterone System with the Aging Process Based on Sodium Wasting Human Models.

Every individual at some point encounters the progressive biological process of aging, which is considered one of the major risk factors for common diseases. The main drivers of aging are oxidative stress, senescence, and reactive oxygen species (ROS). The renin-angiotensin-aldosterone system (RAAS) includes several systematic processes for the regulation of blood pressure, which is caused by an imbalance of electrolytes. During activation of the RAAS, binding of angiotensin II (ANG II) to angiotensin II type 1 receptor (AGTR1) activates intracellular nicotinamide adenine dinucleotide phosphate (NADPH) oxidase to generate superoxide anions and promote uncoupling of endothelial nitric oxide (NO) synthase, which in turn decreases NO availability and increases ROS production. Promoting oxidative stress and DNA damage mediated by ANG II is tightly regulated. Individuals with sodium deficiency-associated diseases such as Gitelman syndrome (GS) and Bartter syndrome (BS) show downregulation of inflammation-related processes and have reduced oxidative stress and ROS. Additionally, the histone deacetylase sirtuin-1 (SIRT1) has a significant impact on the aging process, with reduced activity with age. However, GS/BS patients generally sustain higher levels of sirtuin-1 (SIRT1) activity than age-matched healthy individuals. SIRT1 expression in GS/BS patients tends to be higher than in healthy age-matched individuals; therefore, it can be assumed that there will be a trend towards healthy aging in these patients. In this review, we highlight the importance of the hallmarks of aging, inflammation, and the RAAS system in GS/BS patients and how this might impact healthy aging. We further propose future research directions for studying the etiology of GS/BS at the molecular level using patient-derived renal stem cells and induced pluripotent stem cells.

Renoprotective Effects of Daprodustat in Patients with Chronic Kidney Disease and Renal Anemia.

Many large-scale studies revealed that exogenous erythropoietin, erythropoiesis-stimulating agents, have no renoprotective effects. We reported the renoprotective effects of endogenous erythropoietin production on renal function in ischemic reperfusion injury (IRI) of the kidney using the prolyl hydroxylase domain (PHD) inhibitor, Roxadustat. The purpose of this study was to investigate the effects of daprodustat on the progression of chronic renal failure. We retrospectively investigated the effects of daprodustat on the progression of chronic renal failure and renal anemia in patients with stages 3a-5 chronic kidney diseases (estimated glomerular filtration rate, eGFR < 60 mL/min/1.73 m2). The results show that daprodustat largely slowed the reduction in eGFR. The recovery of renal function was observed in some patients. Daprodustat is useful not only for renal anemia but also for the preservation of renal function. The renoprotective effect of daprodustat was small in patients with serum creatinine larger than 3-4 mg/dL because of low residual renal function. The appearance of renal anemia would be a sign of the time to start using daprodustat.

Biomonitoring of Heavy Metal Toxicity in Freshwater Canals in Egypt Using Creeping Water Bugs (Ilyocoris cimicoides): Oxidative Stress, Histopathological, and Ultrastructural Investigations.

The abundance of metal pollutants in freshwater habitats poses serious threats to the survival and biodiversity of aquatic organisms and human beings. This study intends for the first time to assess the pernicious influences of heavy metals in Al Marioteya canal freshwater in Egypt, compared to Al Mansoureya canal as a reference site utilizing the creeping water bug (Ilyocoris cimicoides) as an ecotoxicological model. The elemental analysis of the water showed a significantly higher incidence of heavy metals, including cadmium (Cd), cobalt (Co), chromium (Cr), nickel (Ni), and lead (Pb), in addition to the calcium (Ca) element than the World Health Organization's (WHO) permitted levels. The Ca element was measured in the water samples to determine whether exposure to heavy metals-induced oxidative stress engendered Ca deregulation in the midgut tissues of the creeping water bug. Remarkably, increased levels of these heavy metals were linked to an increase in chemical oxygen demand (COD) at the polluted site. Notably, the accumulation of these heavy metals in the midgut tissues resulted in a substantial reduction in antioxidant parameters, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and ascorbate peroxidase (APOX), along with a marked rise in malondialdehyde (MDA), cytochrome P450, and protein carbonyl levels. These results clearly indicate a noticeable disturbance in the antioxidant defense system due to uncontrollable reactive oxygen species (ROS). Notably, the results demonstrated that oxidative stress caused disturbances in Ca levels in the midgut tissue of I. cimicoides from polluted sites. Furthermore, the comet and flow cytometry analyses showed considerable proliferations of comet cells and apoptotic cells in midgut tissues, respectively, exhibiting prominent correlations, with pathophysiological deregulation. Interestingly, histopathological and ultrastructural examinations exposed noticeable anomalies in the midgut, Malpighian tubules, and ovarioles of I. cimicoides, emphasizing our findings. Overall, our findings emphasize the potential use of I. cimicoides as a bioindicator of heavy metal pollution in freshwater to improve sustainable water management in Egypt.

The Impact of the Angiotensin-Converting Enzyme Inhibitor Lisinopril on Metabolic Rate in Drosophila melanogaster.

Evidence suggests that angiotensin-converting enzyme inhibitors (ACEIs) may increase metabolic rate by promoting thermogenesis, potentially through enhanced fat oxidation and improved insulin. More research is, however, needed to understand this intricate process. In this study, we used 22 lines from the Drosophila Genetic Reference Panel to assess the metabolic rate of virgin female and male flies that were either fed a standard medium or received lisinopril for one week or five weeks. We demonstrated that lisinopril affects the whole-body metabolic rate in Drosophila melanogaster in a genotype-dependent manner. However, the effects of genotypes are highly context-dependent, being influenced by sex and age. Our findings also suggest that lisinopril may increase the Drosophila metabolic rate via the accumulation of a bradykinin-like peptide, which, in turn, enhances cold tolerance by upregulating Ucp4b and Ucp4c genes. Finally, we showed that knocking down Ance, the ortholog of mammalian ACE in Malpighian/renal tubules and the nervous system, leads to opposite changes in metabolic rate, and that the effect of lisinopril depends on Ance in these systems, but in a sex- and age-specific manner. In conclusion, our results regarding D. melanogaster support existing evidence of a connection between ACEI drugs and metabolic rate while offering new insights into this relationship.

The possible effects of chronic administration of amiodarone hydrochloride on the seminiferous tubules of adult male albino rats: histological and biochemical study.

Amiodarone hydrochloride is an antiarrhythmic agent that is widely prescribed. However, it has serious side effects that approximately affect the whole body organs. In our study, we aimed to assess the possible effects of chronic administration of two different doses of amiodarone hydrochloride on the oxidative and inflammatory parameters as well as the histological morphology and ultrastructure of the seminiferous tubules of adult male albino rats. Forty rats were divided into four groups; Control group 1: each rat did not receive any drugs at all. Control group 2: each rat received 3 ml of 0.16% methylcellulose, orally and daily for 4 weeks. Low dose amiodarone group: each rat received 3 ml of 0.16% methylcellulose contained 3.6 mg amiodarone, orally and daily for 4 weeks. High dose amiodarone group: each rat received 3 ml of 0.16% methylcellulose contained 7.2 mg amiodarone, orally and daily for 4 weeks. Blood samples were collected for measuring serum levels of malondialdehyde, superoxide dismutase, interleukin-6 and tumor necrosis factor-alpha. Testes specimens were examined to assess the morphological changes and the level of expression of caspase-3 apoptotic marker. The results indicated that; amiodarone hydrochloride could induce a dose-dependent toxicity, causing oxidative stress, inflammation, cellular degeneration, deposition of collagen and enhanced apoptosis in the seminiferous tubules.

Left ventricular structure and function in relation to sodium dietary intake and renal handling in untreated Chinese patients.

Whether left ventricular structure and function is associated with sodium dietary intake and renal handling while considering blood pressure (BP) remains unclear. Consecutive untreated patients referred for ambulatory BP monitoring were recruited. Standard echocardiography was performed to measure left ventricular structure and function. Fractional excretion of lithium (FELi) and fractional distal reabsorption rate of sodium (FDRNa) were calculated as markers of proximal and distal tubular sodium handling, respectively. The 952 participants (51.0% women; mean age, 50.8 years) included 614 (64.5%) ambulatory hypertension and 103 (10.8%) left ventricular hypertrophy. There were significant interactions of urinary sodium excretion with FELi (P ≤ 0.045), but not FDRNa (P ≥ 0.36), in relation to left ventricular posterior wall thickness (LVPW), mass (LVM) and mass index (LVMI), but not functional measurements. Only in tertile 1 of FELi, the multivariate-adjusted regression coefficients for urinary sodium excretion reached statistical significance (P ≤ 0.049), being 0.16 ± 0.05 mm, 4.32 ± 1.48 g, and 1.64 ± 0.83 g/m2 for LVPW, LVM and LVMI, respectively. In mutually adjusted analyses, the regression coefficient for LVMI was statistically significant for FELi, FDRNa and 24-h systolic BP, being -2.17 ± 0.49, -1.95 ± 0.54, and 2.99 ± 0.51 g/m2, respectively (P < 0.001). Multivariable analysis of variance showed that sodium renal handling indexes (P ≥ 0.14), but not sodium urinary excretion (P = 0.007), were similarly as 24-h BP associated with LVMI. Heat maps on left ventricular hypertrophy provided a graphical confirmation of the findings. Sodium dietary intake and renal handling interact to be associated with left ventricular structure. Renal handling indexes were similarly in size as, jointly in action with and independently of 24-h BP.

A bifunctional lactoferrin-derived amyloid coating prevents bacterial adhesion and occludes dentinal tubules via deep remineralization.

Dentin hypersensitivity (DH) manifests as sharp and uncomfortable pain due to the exposure of dentinal tubules (DTs) following the erosion of tooth enamel. Desensitizing agents commonly used in clinical practice have limitations such as limited depth of penetration, slow remineralization and no antimicrobial properties. To alleviate these challenges, our study designed a lactoferrin-derived amyloid nanofilm (PTLF nanofilm) inspired by the saliva-acquired membrane (SAP). The nanofilm utilises Tris(2-carboxyethyl)phosphine (TCEP) to disrupt the disulfide bonds of lactoferrin (LF) under physiological conditions. The PTLF nanofilm modifies surfaces across various substrates and effectively prevents the early and stable adhesion of cariogenic bacteria, such as Streptococcus mutans and Lactobacillus acidophilus. Simultaneously, it adheres rapidly and securely to demineralized dentin surfaces, facilitating in-situ remineralization of HAP through a simple immersion process. This leads to the formation of a remineralized layer resembling natural dentin, with an occlusion depth of dentinal tubules exceeding 80 µm after three days. The in vivo and vitro results confirm that the PTLF nanofilm possesses good biocompatibility and its ability to exert simultaneous antimicrobial effects and dentin remineralization. Accordingly, this innovative bifunctional PTLF amyloid coating offers promising prospects for the management of DH-related conditions. STATEMENT OF SIGNIFICANCE.

Metabolic alkalosis in cystic fibrosis: from vascular volume depletion to impaired bicarbonate excretion.

Cystic fibrosis (CF) is the most common life-threatening genetic disease in the United States and among people of European descent. Despite the widespread distribution of the cystic fibrosis transmembrane conductance regulator (CFTR) along kidney tubules, specific renal phenotypes attributable to CF have not been well documented. Recent studies have demonstrated the downregulation of the apical Cl-/HCO3 - exchanger pendrin (Slc26a4) in kidney B-intercalated cells of CF mouse models. These studies have shown that kidneys of both mice and humans with CF have an impaired ability to excrete excess HCO3 -, thus developing metabolic alkalosis when subjected to excess HCO3 - intake. The purpose of this minireview is to discuss the latest advances on the role of pendrin as a molecule with dual critical roles in acid base regulation and systemic vascular volume homeostasis, specifically in CF. Given the immense prevalence of vascular volume depletion, which is primarily precipitated via enhanced chloride loss through perspiration, we suggest that the dominant presentation of metabolic alkalosis in CF is due to the impaired function of pendrin, which plays a critical role in systemic vascular volume and acid base homeostasis.

Linking periodontal pathogens with endoperio lesions.

Endodontic-periodontal diseases pose difficulties for the practitioner in diagnosing and predicting the success of the affected teeth. Therefore, it is of interest to correlate between periodontal infections and endodontic periodontal disorders. 50 patients of both sexes were included in this study. 28 of the 50 patients were men and 22 were women. Participants with a history of endodontic and periodontal lesions on the same tooth were chosen. A polymerase chain reaction experiment was carried out and relationships were formed. Data shows that isolates of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Tannerella forsythia were identified in 91% of the periodontium, 12% of the endodontium, and 51% of the endodontium, respectively. Targeted bacterial species were associated with periodontal and endodontic disorders that occurred concurrently. Therefore, it is plausible to speculate that dentinal tubules serve as a channel for the dissemination of microorganisms.

The potential protective effect of propolis on diabetic nephropathy induced by streptozotocin in adult albino rats.

Diabetes mellitus is a common metabolic disorder. It is associated with serious life-threatening complications if not properly managed. The current study aimed at investigating the possible protective role of propolis on streptozotocin-induced diabetic nephropathy. A diabetic rat model was induced by a single intraperitoneal injection of 55 mg/kg streptozotocin. After 4 days, the diabetic rats received oral propolis (300 mg/kg/day) via gastric gavage for 28 days. Biochemical, histopathological and ultrastructural evaluations were performed. The results showed that: streptozotocin-induced diabetes was associated with a marked decrease in the serum high-density lipoproteins and antioxidant enzymes. However, a significant elevation in the levels of serum creatinine, blood urea nitrogen, uric acid, cholesterol, triglycerides and low-density lipoproteins was detected. Furthermore, streptozotocin treatment induced histopathological alterations of the renal cortex; in the form of distorted glomerular capillaries, widened Bowman's space and signs of epithelial tubular degeneration. Ultra-structurally, thickening and irregularity of the glomerular basement membrane and podocytes foot processes effacement were observed. The tubular epithelial cells showed swollen vacuolated mitochondria, scarce basal infoldings and loss of microvilli. Conversely, propolis partially restored the normal lipid profile, antioxidant biomarkers and renal cortical morphology. Propolis exhibited a sort of renoprotection through hypoglycemic, anti-hyperlipidemic and antioxidant effects.

The ultrastructure of peroxisomes in the kidney of the camel (Camelus dromedarius).

Dromedary camels can survive and reproduce in desert areas. The unique anatomical structure of the kidney enables the camel to prevent water loss. The present study aimed to investigate the ultrastructure of the peroxisomes in the normal kidney of the adult dromedary camel. Tissue samples were taken from the cortex and outer medulla of the kidney of eight camels. The samples were then processed for histological and ultrastructural investigations. The epithelial cells of the proximal tubules displayed peroxisomes with varying sizes and shapes. The peroxisomes were observed in either dispersed or clustered arrangement. Each peroxisome exhibited a homogenous matrix enveloped by a single membrane. Several peroxisomes exhibited one or more dark marginal plates that were always strongly associated with the smooth endoplasmic reticulum. The intensity of the peroxisomal matrix differed significantly, either within the same cell or across different cells. The intensity was light or dark, with a few peroxisomes presenting a similar intensity to that of the mitochondria. Some peroxisomes contained nucleoids within their matrix. The peroxisomes in the first and second sections of proximal convoluted tubules were scattered and primarily located in the region between the microvilli and the underlying mitochondria. The peroxisomes in the third region were abundant and frequently aggregated in clusters throughout the cytoplasm. In the fourth region, the number of peroxisomes was low. The proximal straight tubule had a limited quantity of peroxisomes. In conclusion, peroxisomes in the proximal tubule in kidney of normal dromedary camel were similar in shape and size to other mammals; however, heterogeneity exists as a result of differences in species-specific peroxisomal proteins. Peroxisomes are suggested to be a major source of metabolic energy and act as hydrogen peroxide (H2O2) scavengers, resulting in the release of water and oxygen.

A promising approach utilising photothermal energy to disinfect the root canal system: An in vitro investigation.

This study aimed to assess root canal disinfection through various irrigation protocols, including a novel photothermal system called 'LEAP'. Mandibular premolars were infected with Enterococcus faecalis and divided into five groups for different treatments: Group 1: standard needle irrigation; Group 2: passive ultrasonic irrigation; Group 3: GentleWave; Group 4: LEAP; and Group 5: Group 1 + Group 4. Microbial counts were measured before (S1) and after disinfection (S2) using colony-forming units (CFU) and confocal laser scanning microscopy (CLSM). Results revealed a significant reduction in bacterial counts for all groups (p < 0.05). While the percentage of dead bacteria near the canal wall (0-50 µm) did not differ significantly, at 50-150 µm, LEAP and SNI + LEAP exhibited significantly higher bacterial reduction than other groups (p < 0.05). The findings indicate that LEAP is comparable to existing irrigation devices in the main root canal and notably superior in tubular disinfection.

Evaluation of the Potential Protectivity of Both Allium sativum and Zingiber officinale on the Cadmium-Induced Testicular Damage in Rats.

Background: Cadmium (Cd) is a widely spread environmental pollutant, listed among the unsafe metals due to known toxic effects on multiple organs, including the testes. In this study, we aim to evaluate the potential protectivity of garlic and ginger extracts on Cd-induced damage of the testis in rats. Materials and Methods: Fifty-six adult male albino rats were alienated into seven groups; control group, garlic-treated group, and ginger-treated group were given garlic and ginger extracts at doses of 250 mg and 120 mg/kg b.wt/day, Cd-treated group received 8.8 mg/Kg b.wt/day of Cd chloride, and the protected groups were given Cd and co-treated with garlic, ginger, or both extracts. The testes were subjected to different procedures to assess the oxidative status and histopathological changes. Results: Cd-treated rats showed a significant reduction in the testis weight and morphometric measurements of the seminiferous tubules compared to the control group. Cd administration resulted in a marked drop in the testosterone level and activities of antioxidative enzymes. Moreover, Cd induced histopathological changes in the seminiferous tubules. Co-administration of garlic and ginger extracts with the Cd showed partial improvement in the investigated parameters toward the control figures and improvement in the morphological changes. Co-treating both extracts together and the Cd resulted in complete normalization of these adverse effects of Cd. Conclusion: These findings indicated that garlic and ginger extracts could ameliorate the harmful effects of Cd on the testis. This effect was more prominent when garlic and ginger extracts were co-administered together with Cd.

Cytochrome b5 reductase 3 overexpression and dietary nicotinamide riboside supplementation promote distinctive mitochondrial alterations in distal convoluted tubules of mouse kidneys during aging.

The kidney undergoes structural and physiological changes with age, predominantly studied in glomeruli and proximal tubules. However, limited knowledge is available about the impact of aging and anti-aging interventions on distal tubules. In this study, we investigated the effects of cytochrome b5 reductase 3 (CYB5R3) overexpression and/or dietary nicotinamide riboside (NR) supplementation on distal tubule mitochondria. Initially, transcriptomic data were analyzed to evaluate key genes related with distal tubules, CYB5R3, and NAD+ metabolism, showing significant differences between males and females in adult and old mice. Subsequently, our emphasis focused on assessing how these interventions, that have demonstrated the anti-aging potential, influenced structural parameters of distal tubule mitochondria, such as morphology and mass, as well as abundance, distance, and length of mitochondria-endoplasmic reticulum contact sites, employing an electron microscopy approach. Our findings indicate that both interventions have differential effects depending on the age and sex of the mice. Aging resulted in an increase in mitochondrial size and a decrease in mitochondrial abundance in males, while a reduction in abundance, size, and mitochondrial mass was observed in old females when compared with their adult counterparts. Combining both the interventions, CYB5R3 overexpression and dietary NR supplementation mitigated age-related changes; however, these effects were mainly accounted by NR in males and by transgenesis in females. In conclusion, the influence of CYB5R3 overexpression and dietary NR supplementation on distal tubule mitochondria depends on sex, genotype, and diet. This underscores the importance of incorporating these variables in subsequent studies to comprehensively address the multifaceted aspects of aging.

Functional consequences of changes in the distribution of Ca2+ extrusion pathways between t-tubular and surface membranes in a model of human ventricular cardiomyocyte.

The sarcolemmal Ca2+ efflux pathways, Na+-Ca2+-exchanger (NCX) and Ca2+-ATPase (PMCA), play a crucial role in the regulation of intracellular Ca2+ load and Ca2+ transient in cardiomyocytes. The distribution of these pathways between the t-tubular and surface membrane of ventricular cardiomyocytes varies between species and is not clear in human. Moreover, several studies suggest that this distribution changes during the development and heart diseases. However, the consequences of NCX and PMCA redistribution in human ventricular cardiomyocytes have not yet been elucidated. In this study, we aimed to address this point by using a mathematical model of the human ventricular myocyte incorporating t-tubules, dyadic spaces, and subsarcolemmal spaces. Effects of various combinations of t-tubular fractions of NCX and PMCA were explored, using values between 0.2 and 1 as reported in animal experiments under normal and pathological conditions. Small variations in the action potential duration (≤ 2%), but significant changes in the peak value of cytosolic Ca2+ transient (up to 17%) were observed at stimulation frequencies corresponding to the human heart rate at rest and during activity. The analysis of model results revealed that the changes in Ca2+ transient induced by redistribution of NCX and PMCA were mainly caused by alterations in Ca2+ concentrations in the subsarcolemmal spaces and cytosol during the diastolic phase of the stimulation cycle. The results suggest that redistribution of both transporters between the t-tubular and surface membranes contributes to changes in contractility in human ventricular cardiomyocytes during their development and heart disease and may promote arrhythmogenesis.

Identification of a gene promoter active in Lucilia sericata larval salivary glands using a rapid transient expression assay.

Tissue-specific gene promoters are desired as they provide the specificity needed for control of gene expression in transgenic animals. Here we describe a relatively rapid two-component transient expression assay that was used to identify a gene promoter active in the larval salivary glands of the green blow fly, Lucilia sericata. Sterile L.sericata maggots are widely used for wound debridement. A larval salivary gland gene promoter could be used to make maggots that secrete factors for enhanced wound therapy. Embryos from a line that carry a tetracycline transactivator (tTA)-activated red fluorescent protein gene were injected with plasmid DNA with the tTA gene driven by a constitutive or tissue-specific gene promoter. The hatched larvae were reared on diet and then examined for red fluorescence. A promoter from the LsCG30371 gene was active in the larval salivary glands. The tissue-specificity of the promoter was subsequently confirmed with stable transgenic lines that carried the LsCG30371-tTA gene. The relatively rapid transient expression assay could potentially be used to determine the tissue-specificity of other gene promoters. Further, the stable LsCG30371-tTA lines could be used to make sterile maggots that secrete factors from the salivary glands for enhanced wound healing.

An SEM study on the effect of 9.3-µm CO2 laser on dentinal tubules for hypersensitivity treatment.

OBJECTIVES: In-vitro studies were performed on dentin of extracted human molars to investigate the effectiveness of 9.3 µm CO2 laser irradiation to occlude dentinal tubules. The observed occlusion of dentinal tubules with the irradiation was compared with application of three reagents: 2% Sodium Fluoride gel, an aqueous solution of hydroxyapatite nanoparticles and an equal mix of the two. We show that 9.3 µm CO2 laser irradiation occludes dentinal tubules, and the use of laser irradiation produces better occlusion of the opened tubules compared to the use of topical reagents. METHODS: Nine extracted and cleaned human molars were cut to obtain dentin disks of thickness of 3-5 mm. Each disc was divided into four quarters, and each quarter served as two samples corresponding to irradiated and non-irradiated group counterparts. Five disks were used to study the effect of various laser irradiation energies on the dentinal tubules to find a good pulse fluence for occlusion of the dentinal tubules, and four disks were used for studying the effects of reagents and irradiation at the pulse fluences found in the first part of the study. The samples were irradiated with a beam diameter of 1 mm (1/e2) at 15 Hz pulse repetition rate, scanned automatically using a set of scanning mirrors. Samples were imaged using Scanning Electron Microscope (SEM) which were processed to determine tubule diameter. Safety of the irradiation treatment was investigated on 6 samples by measuring pulpal temperature rise. The effect of three topical reagents corresponding to 2% Sodium Fluoride gel (F), Hydroxyapatite nanoparticles (HA) and an equal mix of F and HA (HAF) on dentinal tubule occlusion was evaluated and compared with the laser irradiation. RESULTS: In all examined cases, laser irradiation at a fluence of 0.81 J/cm2 resulted in a temperature increase less than 3 °C which is safe, and no surface cracking was observed. There is a threshold pulse fluence of 0.27 J/cm2 above which, laser produced surface melting. At a pulse fluence of 0.81 J/cm2 a layer of recast of melted dentin was formed. Under this layer, peritubular dentin melting and occluding of the dentinal tubules was observed. Application of either F or HA or HAF did not produce visible occlusion effect on open tubules after washing and microbrushing with excess distilled water. CONCLUSIONS: 9.3 µm CO2 laser irradiation on extracted human molar dentin at pulse fluence of 0.81 J./cm2 resulted in tubule area reduction by 97% without rising pulpal temperatures to unsafe levels.