[Intraoperative opacification of a scleral-fixated Carlevale (Soleko®) intraocular lens]. / Opacification peropératoire d'un implant fixé à la sclère Carlevale (Soleko®).

Thermal shock can cause intraoperative opacification of a Carlevale (Soleko®) implant. This is a rare phenomenon which resolves spontaneously. It is crucial to recognise this phenomenon in order to avoid unnecessary and potentially harmful explantation decisions for the patient.

The value of immediate postoperative radiographs following fluoroscopically-guided orthopaedic surgery in a polytrauma ICU setting in KwaZulu-Natal, South Africa.

BACKGROUND: Radiographic imaging remains a cornerstone of orthopaedic practice. Traditional control X-Rays are routinely requested after procedures. These X-rays may add little value in post-op evaluation of trauma ICU patients, in light of intra-operative screening already performed and reviewed, but has high potential morbidity risk. AIM: The aim is to determine if patients undergoing extra-articular fracture fixation, with fluoroscopic image guidance, require any management change due to immediate check x-rays findings. METHOD: Electronic patient and imaging records from January 2015 to November 2019 at a Trauma-specific ICU at a Trauma Society of South Africa accredited, Level 1 Trauma Unit were reviewed retrospectively. All patients matching the inclusion criteria were evaluated to determine if there were any complications and changes in management after the check X-Rays. RESULTS: There were 103 ICU patients identified with a mean age of 32 years (3 to 94). Fifty-seven percent had fluoroscopy images as well as post-operative check x-rays and 51.5% had only check X-rays. Only two cases needed revision surgery based on the control x-ray findings. The post-operative x-ray did not alter the management of 98.1% of our patients. CONCLUSION: In this study, routine post-op check x-rays did not add significant additional information to warrant early additional surgical intervention especially in ICU patients with adequate intra-operative fluoroscopy images. This investigation should be ordered for individual patients based on clinical grounds. This will help minimize patient exposure to avoidable radiation, labour intensive transfers to the radiology department, and decrease investigations that have financial implications but with limited benefits.

The Calcium-Sensing Receptor in Health and Disease.

The extracellular calcium-sensing receptor (CaSR) is a unique G protein-coupled receptor (GPCR) activated by extracellular Ca2+ and by other physiological cations including Mg2+, amino acids, and polyamines. CaSR is the most important master controller of the extracellular Ca2+ homeostatic system being expressed at high levels in the parathyroid gland, kidney, gut and bone, where it regulates parathyroid hormone (PTH) secretion, vitamin D synthesis, and Ca2+ absorption and resorption, respectively. Gain and loss of function mutations in the CaSR are responsible for severe disturbances in extracellular Ca2+ metabolism. CaSR agonists (calcimimetics) and antagonists (calcilytics) are in use or under intense research for treatment of hyperparathyroidism secondary to kidney failure and hypocalcemia with hypercalciuria, respectively. Expression of the CaSR extends to other tissues and systems beyond the extracellular Ca2+ homeostatic system including the cardiovascular system, the airways, and the nervous system where it may play physiological functions yet to be fully understood. As a consequence, CaSR has been recently involved in different pathologies including uncontrolled blood pressure, vascular calcification, asthma, and Alzheimer's disease. Finally, the CaSR has been shown to play a critical role in cancer either contributing to bone metastasis and/or acting as a tumor suppressor in some forms of cancer (parathyroid cancer, colon cancer, and neuroblastoma) and as oncogene in others (breast and prostate cancers). Here we review the role of CaSR in health and disease in calciotropic tissues and others beyond the extracellular calcium homeostatic system.

Experimental Observations on the Biological Significance of Hydrogen Sulfide in Carotid Body Chemoreception.

The cascade of transduction of hypoxia and hypercapnia, the natural stimuli to chemoreceptor cells, is incompletely understood. A particular gap in that knowledge is the role played by second messengers, or in a most ample term, of modulators. A recently described modulator of chemoreceptor cell responses is the gaseous transmitter hydrogen sulfide, which has been proposed as a specific activator of the hypoxic responses in the carotid body, both at the level of the chemoreceptor cell response or at the level of the global output of the organ. Since sulfide behaves in this regard as cAMP, we explored the possibility that sulfide effects were mediated by the more classical messenger. Data indicate that exogenous and endogenous sulfide inhibits adenyl cyclase finding additionally that inhibition of adenylyl cyclase does not modify chemoreceptor cell responses elicited by sulfide. We have also observed that transient receptor potential cation channels A1 (TRPA1) are not regulated by sulfide in chemoreceptor cells.

Epididymal mitochondrial status of hypothyroid rats examined by transmission electron microscopy.

Hypothyroid rats show alterations in the mobility of sperm recovered from their epididymides. The AgNOR technique, immunohistochemistry and transmission electron microscopy were used to investigate changes in epithelial cells from epididymides of rats treated with (131)I. Counting of NORs did not permit detection of changes in the proliferative capacity of epididymides of hypothyroid animals. Transmission electron microscopy revealed changes in the mitochondria of hypothyroid rats that probably are associated with incipient apoptosis.

AgNOR, p16 and human papillomavirus in low-grade squamous intra-epithelial lesions of the uterine cervix. Preliminary report.

It has been shown that infection with high-risk human papillomaviruses (HR-HPV) is related to the development of cervical cancer. The persistence of the virus in intra-epithelial lesions of cervix uteri (SILs) is the basis for the application of HPV testing for screening and management of patients. Most infections by HR-HPVs resolve spontaneously, however, and do not progress to dysplasia or cancer. p16INK4a is a useful biomarker of cervical intra-epithelial neoplasia and could be a marker for the progression of low-grade squamous intra-epithelial lesions (LSILs) to high-grade squamous intra-epithelial lesions (HSILs), because it correlates independently with increasing SIL grade. We conducted a preliminary histological study of 28 patients diagnosed with LSIL, HSIL or nondysplastic epithelium (NDE) from whom 28 biopsies of uterine cervix and 28 endocervical brushed biopsies were taken. Argyrophilic nucleolar organizer region (AgNOR) and p16INK4a assays were performed on the biopsies, and endocervical brushings were used for HPV typing. The high risk HPV group showed that the number of patients with AgNOR areas greater than 3.3 µm(2) and with expression of p16INK4a were statistically greater than the number of lower risk patients. None of the biopsies of LR-HPV carriers expressed p16 and AgNOR areas> 3.3 µm(2) simultaneously. Four LSILs and the NDE of this group expressed neither of the two markers. If the correlation between AgNOR areas and p16INK4a is good, we may be able to develop a low cost simple technology for studying patients infected with HR-HPV and diagnosed with LSIL of uncertain behavior.

Spermine attenuates carotid body glomus cell oxygen sensing by inhibiting L-type Ca²(+) channels.

An increase in intracellular Ca²(+) is crucial to O2 sensing by the carotid body. Polyamines have been reported to modulate both the extracellular Ca²(+)-sensing receptor (CaR) and voltage-gated Ca²(+) channels in a number of cell types. Using RT-PCR and immunohistochemistry, the predominant voltage-gated Ca²(+) channels expressed in the adult rat carotid body were L (Ca(V)1.2) and N (Ca(V)2.2)-type. CaR mRNA could not be amplified from carotid bodies, but the protein was expressed in the nerve endings. Spermine inhibited the hypoxia-evoked catecholamine release from isolated carotid bodies and attenuated the depolarization- and hypoxia-evoked Ca²(+) influx into isolated glomus cells. In agreement with data from carotid body, recombinant Ca(V)1.2 was also inhibited by spermine. In contrast, the positive allosteric modulator of CaR, R-568, was without effect on hypoxia-induced catecholamine release from carotid bodies and depolarization-evoked Ca²(+) influx into glomus cells. These data show that spermine exerts a negative influence on carotid body O2 sensing by inhibiting L-type Ca²(+) channels.

Sensitivity and specificity of cytodiagnosis of body fluids in a laboratory of urgencies.

The main purpose for studying cytological body fluids is confirmation of a benign or malignant effusion. Our cytology laboratory analyzes body fluids and results are requested urgently. The samples are stained by the Giemsa and Papanicolaou methods to give a preliminary report, then they are examined by other complementary techniques. Three hundred thirty samples of pleural and peritoneal fluids were studied to compare the sensitivity of Papanicolaou and Giemsa stains. AgNOR assay, immunocytochemistry and assessment of ploidy were used to improve the sensitivity of the cytodiagnosis. Two hundred one samples were positive, 84 negative and 45 inconclusive using the Papanicolaou stain, while 135 samples were positive, 72 negative and 123 inconclusive using Giemsa stain. The sensitivity was 79%, 53% and 83% for Papanicolaou, Giemsa, and both techniques together, respectively. Using complementary techniques, the sensitivity reached 95% for AgNOR, 87% for tumor markers (panel), and 92% for Ploidy. There were no false positive in our series; therefore specificity was 100%. The use of both Papanicolaou and Giemsa in conjunction increased the sensitivity of the cytodiagnosis in body fluids. The complementary methods, especially AgNOR assay and assessment of ploidy, diminished the number of inconclusive cases.

Prognostic value of germ cells in the ejaculate: a case study.

The first approach to assessing male fertility is to study a spermiogram, where special attention is given to sperm count, motility and morphology, while less attention is given to other cells in the ejaculate. Normal spermatogenesis requires a balance between cell death and proliferation; therefore, the number of germ cells (GC) in the ejaculate is less than the number of sperm. We propose a new index for altered spermatogenesis, i.e., the rate GC/sperm. We investigated a patient with oligozoospermia and a GC/sperm ratio greater than one, which indicated that spermatogenesis had been damaged. Complementary cytological tests were employed to characterized GC status: Papanicolaou stain, transmission electronic microscopy (TEM), vitality test, AgNOR and TUNEL assay. We also correlated cell morphology with ultrastructure studies that showed apoptosis. Nuclear apoptosis is characterized by vacuolization, misshapen nuclei, and "half moon," dispersed, uncondensed, disrupted and smudged chromatin. Cytoplasmic apoptosis is characterized by vacuolization, cytoplasmic protrusions, lamellar bodies, and swollen endoplasmic reticulum and mitochondria. To date, only testicular biopsy has been used to diagnose complete or incomplete testicular arrest. Our investigation is the first to determine a cytological feature in semen samples that could be used as a biological marker for abnormal spermatogenesis and for predicting the transition from oligospermia to azoospermia.

A revisit to O2 sensing and transduction in the carotid body chemoreceptors in the context of reactive oxygen species biology.

Oxygen-sensing and transduction in purposeful responses in cells and organisms is of great physiological and medical interest. All animals, including humans, encounter in their lifespan many situations in which oxygen availability might be insufficient, whether acutely or chronically, physiologically or pathologically. Therefore to trace at the molecular level the sequence of events or steps connecting the oxygen deficit with the cell responses is of interest in itself as an achievement of science. In addition, it is also of great medical interest as such knowledge might facilitate the therapeutical approach to patients and to design strategies to minimize hypoxic damage. In our article we define the concepts of sensors and transducers, the steps of the hypoxic transduction cascade in the carotid body chemoreceptor cells and also discuss current models of oxygen- sensing (bioenergetic, biosynthetic and conformational) with their supportive and unsupportive data from updated literature. We envision oxygen-sensing in carotid body chemoreceptor cells as a process initiated at the level of plasma membrane and performed by a hemoprotein, which might be NOX4 or a hemoprotein not yet chemically identified. Upon oxygen-desaturation, the sensor would experience conformational changes allosterically transmitted to oxygen regulated K+ channels, the initial effectors in the transduction cascade. A decrease in their opening probability would produce cell depolarization, activation of voltage dependent calcium channels and release of neurotransmitters. Neurotransmitters would activate the nerve endings of the carotid body sensory nerve to convey the information of the hypoxic situation to the central nervous system that would command ventilation to fight hypoxia.

Structural and functional changes in tau mutant mice neurons are not linked to the presence of NFTs.

In the rTg4510 mouse model, expression of the mutant human tau variant P301L leads to development of neurofibrillary tangles (NFTs), neuronal death, and memory impairment, reminiscent of the pathology observed in human tauopathies. In the present study, we examined the effects of mutant tau expression on the electrophysiology and morphology of individual neurons using whole-cell patch-clamp recordings and biocytin filling of pyramidal cells in cortical slices prepared from rTg4510 (TG) and wild-type (WT) littermate mice. Among the TG cells, 42% contained a clear Thioflavin-S positive inclusion in the soma and were categorized as NFT positive (NFT+), while 58% had no discernable inclusion and were categorized as NFT negative (NFT-). The resting membrane potential (V(r)) was significantly depolarized (+8 mV) in TG cells, and as a consequence, evoked repetitive action potential (AP) firing rates were also significantly increased. Further, single APs were significantly shorter in duration in TG cells and the depolarizing voltage deflection or "sag" evoked by hyperpolarization was significantly greater in amplitude. In addition to these functional electrophysiological changes, TG cells exhibited significant morphological alterations, including loss or significant atrophy of the apical tuft, reduced dendritic complexity and length, and reduced spine density. Importantly, NFT- and NFT+ TG cells were indistinguishable with regard to both morphological and electrophysiological properties. Our observations show that expression of mutated tau results in significant structural and functional changes in neurons, but that these changes occur independent of mature NFT formation.

Effects of the polyamine spermine on arterial chemoreception.

Polyamines modulate many biological functions. Here we report a novel inhibitory modulation by spermine of catecholamine release by the rat carotid body and have identified the molecular mechanism underpinning it. We used molecular (RT-PCR and confocal microscopy) and functional (i.e., neurotransmitter release, patch clamp recording and calcium imaging) approaches to test the involvement of: (i) voltage-dependent calcium channels, and; (ii) the extracellular calcium-sensing receptor, CaR, a G protein-coupled receptor which is also activated by polyamines. RT-PCR and immunohistochemistry of isolated carotid bodies revealed that only Ca(v)1.2 and Ca(v)2.2 were expressed in type 1 cells while Ca(v)1.3, Ca(v)1.4, Ca(v)2.1, Ca(v)2.3 and Ca(v)3.1, Ca(v)3.2 and Ca(v)3.3, could not be detected. CaR expression was detected exclusively in the nerve endings. In isolated carotid bodies, the hypoxia-dependent (7% O(2) for 10 minutes) and depolarization-evoked catecholamine release were partially suppressed by pre- (and co)-incubation with 500microM spermine. In dissociated type 1 glomus cells intracellular calcium concentration did not change following spermine treatment, but this polyamine did inhibit the depolarisation-evoked calcium influx. Whole-cell patch clamp recordings of HEK293 cells stably transfected with Ca(v)1.2 demonstrated that spermine inhibits this calcium channel. Interestingly, this inhibition was not apparent if the extracellular solution contained a concentration of Ba(2) above 2 mM as the charge carrier. In conclusion, spermine attenuates catecholamine release by the carotid body principally via inhibition of Ca(v)1.2. This mechanism may represent a negative feedback, which limits transmitter release during hypoxia.

RT-PCR and pharmacological analysis of L-and T-type calcium channels in rat carotid body.

Mechanisms involved in carotid body (CB) chemoreceptor cells O(2)-sensing and responses are not fully understood. So far, it is known that hypoxia depolarizes chemoreceptor cells via O(2)-sensitive K(+)-channel inhibition; calcium influx via voltage-gated channels and neurotransmitter secretion follow. Presence of high voltage activated (HVA) calcium channels in rat CB chemoreceptor cells is well documented, but the presence of low voltage activated (LVH) or T-type calcium channels has not been reported to date. The fact that O(2)-sensitive PC12 cells express T-type channels and that they are inducible by chronic hypoxia (CH) lead us to hypothesize they could be present and play a role in the genesis of the hypoxic response in rat CB chemoreceptor cells. We have analyzed the expression of the three isoforms of T-type calcium channels (alpha1G, alpha1H and alpha1I) and the isoforms alpha1C and alpha1D of L-type calcium channels in rat CB by RT-PCR. We found that rat CB expresses alpha1G and alpha1C subunits. After chronic hypoxic treatment of adult rats (10 degrees O(2), 8 days), expression of alpha1G seems to be down-regulated whereas alpha1C expression is up-regulated. Functionally, it was found that the release of catecholamine induced by hypoxia and high external K({+}) from CB chemoreceptor cells was fully sensitive to L-type channel inhibition (nisoldipine, 2 microM), while specific inhibition of T-channels (mibefradil, 2 microM) inhibited exclusively hypoxia-induced release (50 degrees ). As a whole, present findings demonstrate the presence of T-type as well as L-type calcium channels in rat CB and suggest a selective participation of the T-type channels in the hypoxic activation of chemoreceptor cells.

AgNOR technique could be useful for differential diagnosis of squamous carcinomatous cells and atypical cells related to human papillomavirus in cervical smears.

The human papillomavirus (HPV)-associated effect can mimic invasive squamous cell carcinoma. Measurements of the argyrophilic nucleolar organizer region (AgNOR) area of cells from smears with HPV infection of the cervix with marked atypia were carried out to differentiate this pathology from keratinizing carcinomas. After destaining, the smears were incubated in the dark for 25 min with a mixture of silver nitrate and gelatin in formic acid. After washing with deionized water and sodium thiosulfate, the slides were dehydrated and mounted with Canada balsam. The average AgNOR area was determined by image cytometry using the immersion oil objective and selecting 100 cells in each smear. Twenty-three patients with a mean AgNOR area of 1.32 microm(2) among their samples showed normal colposcopies and cervical smears after 18 months. In four patients, whose samples were diagnosed as atypical squamous cells of undetermined significance with viral atypia, the average AgNOR area was 7.70 microm(2); biopsies showed keratinizing squamous carcinomas in three of these cases and moderately differentiated squamous carcinoma in one of them. We propose a cutoff of 2.2 microm(2) for the AgNOR area of cells from smears with HPV infection of the cervix with marked atypia to differentiate this group from keratinizing carcinomas.

Homology modelling of the Apis mellifera nicotinic acetylcholine receptor (nAChR) and docking of imidacloprid and fipronil insecticides and their metabolites.

Five homology models for honeybee (Apis mellifera) nicotinic acetylcholine receptor (nAChR) alpha1/beta1, alpha3/beta2, alpha4/beta2, alpha6/beta2 and alpha9/alpha9 subtypes were built from the Torpedo marmorata nAChR X-ray structure. Then, imidacloprid, fipronil and their metabolites were docked into the ligand binding domain (LBD) of these receptors and the corresponding scoring functions were calculated. The binding modes of the docked compounds were carefully analysed. Finally, multivariate analyses were used for deriving structure-activity relationships based on hydrogen bond number and scoring functions between the insecticides and the nAChR models.

Chemoreception in the context of the general biology of ROS.

Superoxide anion is the most important reactive oxygen species (ROS) primarily generated in cells. The main cellular constituents with capabilities to generate superoxide anion are NADPH oxidases and mitochondrial respiratory chain. The emphasis of our article is centered in critically examining hypotheses proposing that ROS generated by NADPH oxidase and mitochondria are key elements in O(2)-sensing and hypoxic responses generation in carotid body chemoreceptor cells. Available data indicate that chemoreceptor cells express a specific isoform of NADPH oxidase that is activated by hypoxia; generated ROS acting as negative modulators of the carotid body (CB) hypoxic responses. Literature is also consistent in supporting that poisoned respiratory chain can produce high amounts of ROS, making mitochondrial ROS potential triggers-modulators of the CB activation elicited by mitochondrial venoms. However, most data favour the notion that levels of hypoxia, capable of strongly activating chemoreceptor cells, would not increase the rate of ROS production in mitochondria, making mitochondrial ROS unlikely triggers of hypoxic responses in the CB. Finally, we review recent literature on heme oxygenases from two perspectives, as potential O(2)-sensors in chemoreceptor cells and as generators of bilirubin which is considered to be a ROS scavenger of major quantitative importance in mammalian cells.

Usefulness of ploidy, AgNOR and immunocytochemistry for differentiating benign and malignant cells in serous effusions.

OBJECTIVE: The objective of this study was to establish the value of different markers in differentiating reactive mesothelial cells from metastatic adenocarcinomatous cells in serous effusions (SE). METHODS: Forty-five SE were processed for morphological examination (Papanicolaou stain), assessment of ploidy, AgNOR counting and immunocytochemical assay of carcinoembryonic antigen (CEA), epithelial membrane antigens (EMA), Ber-EP4 and Leu-M1. Ploidy was established in an image-analyser in smears stained by the Feulgen stain method. AgNOR dots were counted in the smears stained with the silver nitrate assay for non-histone proteins present in the nucleolar organizer region. CEA, EMA, Ber-EP4 and Leu-M1 were evaluated by immunocytochemistry using the streptavidin-biotin complex method. RESULTS: All the smears with positive cytology were aneuploid. Three false negatives by morphological studies were aneuploid, with AgNOR values in two of them corresponding to the neoplastic group. CEA and Leu-M1 showed a low specificity; EMA and Ber-EP4 showed moderate sensitivity. CONCLUSIONS: The assessment of ploidy and the study of AgNOR were better methods than immunocytochemistry for distinguishing between reactive mesothelial cells and adenocarcinomatous cells in serous fluid.