Antibodies to Aedes aegypti D7L salivary proteins as a new serological tool to estimate human exposure to Aedes mosquitoes

Introduction

Aedes spp. are the most prolific mosquito vectors in the world. Found on every continent, they can effectively transmit various arboviruses, including the dengue virus which continues to cause outbreaks worldwide and is spreading into previously non-endemic areas. The lack of widely available dengue vaccines accentuates the importance of targeted vector control strategies to reduce the dengue burden. High-throughput tools to estimate human-mosquito contact and evaluate vector control interventions are lacking. We propose a novel serological tool that allows rapid screening of human cohorts for exposure to potentially infectious mosquitoes.

Methods

We tested 563 serum samples from a longitudinal pediatric cohort study previously conducted in Cambodia. Children enrolled in the study were dengue-naive at baseline and were followed biannually for dengue incidence for two years. We used Western blotting and enzyme-linked immunosorbent assays to identify immunogenic Aedes aegypti salivary proteins and measure total anti-Ae. aegypti IgG.

Results

We found a correlation (rs=0.86) between IgG responses against AeD7L1 and AeD7L2 recombinant proteins and those to whole salivary gland homogenate. We observed seasonal fluctuations of AeD7L1+2 IgG responses and no cross-reactivity with Culex quinquefasciatus and Anopheles dirus mosquitoes. The baseline median AeD7L1+2 IgG responses for young children were higher in those who developed asymptomatic versus symptomatic dengue.

Discussion

The IgG response against AeD7L1+2 recombinant proteins is a highly sensitive and Aedes specific marker of human exposure to Aedes bites that can facilitate standardization of future serosurveys and epidemiological studies by its ability to provide a robust estimation of human-mosquito contact in a high-throughput fashion.

Antibodies to Aedes aegypti D7L salivary proteins as a new serological tool to estimate human exposure to Aedes mosquitoes

Introduction

Aedes spp. are the most prolific mosquito vectors in the world. Found on every continent, they can effectively transmit various arboviruses, including the dengue virus which continues to cause outbreaks worldwide and is spreading into previously non-endemic areas. The lack of widely available dengue vaccines accentuates the importance of targeted vector control strategies to reduce the dengue burden. High-throughput sensitive tools to estimate human-mosquito contact and evaluate vector control interventions are lacking. We propose a novel serological tool that allows rapid screening of large human cohorts for exposure to potentially infectious mosquitoes and effective targeting of vector control.

Methods

We tested 563 serum samples from a longitudinal pediatric cohort study previously conducted in Cambodia. Children enrolled in the study were dengue-naïve at baseline and were followed biannually for dengue incidence for two years. We used Western blotting and enzyme-linked immunosorbent assays to identify the most immunogenic Aedes aegypti salivary proteins and measure total anti- Ae. Aegypti IgG.

Results

We found a strong correlation (r s =0.86) between the combined IgG responses against AeD7L1 and AeD7L2 recombinant proteins and those to whole salivary gland homogenate. We observed seasonal fluctuations of AeD7L1+2 IgG responses, corresponding to Aedes spp. abundance in the region, and no cross-reactivity with Culex quinquefasciatus and Anopheles dirus mosquitoes. The baseline median AeD7L1+2 IgG responses for young children were higher in those who developed asymptomatic dengue versus those who developed symptomatic dengue.

Conclusion

The IgG response against AeD7L1+2 recombinant proteins is a highly sensitive and Aedes specific marker of human exposure to Aedes bites that can facilitate standardization of future serosurveys and epidemiological studies by its ability to provide a robust estimation of human-mosquito contact in a high-throughput fashion.

SARS-CoV-2 Cross-Reactivity in Prepandemic Serum from Rural Malaria-Infected Persons, Cambodia

Inhabitants of the Greater Mekong Subregion in Cambodia are exposed to pathogens that might influence serologic cross-reactivity with severe acute respiratory syndrome coronavirus 2. A prepandemic serosurvey of 528 malaria-infected persons demonstrated higher-than-expected positivity of nonneutralizing IgG to spike and receptor-binding domain antigens. These findings could affect interpretation of large-scale serosurveys.

Development of inapparent dengue associated with increased antibody levels to Aedes aegypti salivary proteins: a longitudinal dengue cohort in Cambodia

BACKGROUND

We established the first prospective cohort to understand how infection with dengue virus is influenced by vector-specific determinants like humoral immunity to Aedes aegypti salivary proteins.

METHODS

Children aged two to nine years old enrolled in the PAGODAS (Pediatric Assessment Group of Dengue and Aedes Saliva) cohort with informed consent by their guardians. Children were followed semi-annually for antibodies to dengue and to proteins in Ae. aegypti salivary gland homogenate using enzyme-linked immunosorbent assays and dengue-specific neutralization titers. Children presented with fever at any time for dengue testing.

RESULTS

From July 13 to August 30, 2018, we enrolled 771 children. At baseline, 22% (173/770) had evidence of neutralizing antibodies to one or more dengue serotypes. By April 2020, 51 children had symptomatic dengue while 148 dengue-naïve children had inapparent dengue defined by neutralization assays. In a multivariate model, individuals with higher antibodies to Ae. aegypti salivary proteins were 1.5x more likely to have dengue infection (HR 1.47 95% CI 1.05-2.06; p=0.02), particularly individuals with inapparent dengue (HR 1.64 95% CI 1.12-2.41; p=0.01).

CONCLUSIONS

High levels of seropositivity to Ae. aegypti salivary proteins are associated with future development of dengue infection, primarily inapparent, in dengue-naïve Cambodian children.

Pre-pandemic SARS-CoV-2 serological reactivity in rural malaria-experienced Cambodians

Greater Mekong inhabitants are exposed to pathogens, zoonotic and otherwise, that may influence SARS-CoV-2 seroreactivity. A pre-pandemic (2005 to 2011) serosurvey of from 528 malaria-experienced Cambodians demonstrated higher-than-expected (up to 13.8 %) positivity of non-neutralizing IgG to SARS-CoV-2 spike and RBD antigens. These findings have implications for interpreting large-scale serosurveys.

ARTICLE SUMMARY LINE

In the pre-COVID19 pandemic years of 2005 to 2011, malaria experienced Cambodians from rural settings had higher-than-expected seroreactivity to SARS-CoV-2 spike and receptor binding domain proteins.

Influence of thickness and translucency of lithium disilicate ceramic on degree of conversion of resinous materials

Background

In this study was assessed the degree of conversion (DC) of amine-free resin cements light cured through lithium disilicate-reinforced ceramics at different thicknesses and translucency.

Material and Methods

Specimens were divided into 21 groups (n = 5) according to luting agent used: Variolink Esthetic LC (Light shade), RelyX Ultimate (A1 shade), and Filtek Z350 XT Flow (A1 shade); the ceramic translucency: low (LT) and high (HT); and the ceramic thickness: no ceramic (control), 0.5 mm, 1 mm, and 2 mm. A Teflon mold with (5 x 5 x 0.5 mm) was used to standardize the cement and over it the ceramic block from each group was placed. Set was cured using a polywave LED light (1200 mW/cm2 - Bluephase G2) for 40 s. FTIR spectra of uncured and cured materials was obtained and DC calculated from the height of the peaks 1610 and 1640 cm-1. Data were submitted to ANOVA followed by Tukey’s test (α = 0.05).

Results

There was a significant difference for luting agents (p< 0.0001) and translucency (p = 0.025), but not for thickness (p = 0.73). Dual amine-free RelyX Ultimate showed the lowest DC values and higher translucency promoted higher DC.

Conclusions

Dual amine-free cement showed the lowest monomer conversion and higher translucency ceramics promoted a higher DC.

Key words:Ceramic, degree of conversion, resin cement, thickness, translucency.

Nanowire Y-junction formation during self-faceting on high-index GaAs substrates

In this contribution, we report on the observation of high-order and bi-dimensional surface mechanisms that allows the self-assembling of an alternating array of straight and bifurcated nanowires.

Electric radiation mapping of silver/zinc oxide nanoantennas by using electron holography

In this work, we report the fabrication of self-assembled zinc oxide nanorods grown on pentagonal faces of silver nanowires by using microwaves irradiation. The nanostructures resemble a hierarchal nanoantenna and were used to study the far and near field electrical metal-semiconductor behavior from the electrical radiation pattern resulting from the phase map reconstruction obtained using off-axis electron holography. As a comparison, we use electric numerical approximations methods for a finite number of ZnO nanorods on the Ag nanowires and show that the electric radiation intensities maps match closely the experimental results obtained with electron holography. The time evolution of the radiation pattern as generated from the nanostructure was recorded under in-situ radio frequency signal stimulation, in which the generated electrical source amplitude and frequency were varied from 0 to 5 V and from 1 to 10 MHz, respectively. The phase maps obtained from electron holography show the change in the distribution of the electric radiation pattern for individual nanoantennas. The mapping of this electrical behavior is of the utmost importance to gain a complete understanding for the metal-semiconductor (Ag/ZnO) heterojunction that will help to show the mechanism through which these receiving/transmitting structures behave at nanoscale level.

The emergence of the concept of tight junctions and physiological regulation by ouabain

The exchange of substances between metazoan and the environment takes place across transporting epithelia that have two fundamental differentiated features: tight junctions (TJ) and apical/basolateral polarity. Usually, reviews of the structure and function of transporting epithelia follow a historical description of major biological findings, but seldom refer to the fact that it also required fundamental theoretical changes in the physics and chemistry involved. We make a brief description of the concatenation of both types of achievements, in which it becomes clear that the major source of conflicts was the enzyme Na(+),K(+)-ATPase (also referred to as "the pump"), because of its intrinsic mechanisms and its asymmetric expression on one side of epithelial cells only (polarity). This enzyme is also the receptor of the newly recognized hormone ouabain, whose chief function is to modulate cell contacts, such as TJs, several types of cell-cell contacts participating in polarization (as gauged through ciliogenesis).

Cloning, characterization and functional expression of Taenia solium 17 beta-hydroxysteroid dehydrogenase

The 17β-hydroxysteroid dehydrogenases (17β-HSD) are key enzymes involved in the formation (reduction) and inactivation (oxidation) of sex steroids. Several types have been found in vertebrates including fish, as well as in invertebrates like Caenorhabditis elegans, Ciona intestinalis and Haliotis diversicolor supertexta. To date limited information is available about this enzyme in parasites. We showed previously that Taenia solium cysticerci are able to synthesize sex steroid hormones in vitro when precursors are provided in the culture medium. Here, we identified a T. solium 17β-HSD through in silico blast searches in the T. solium genome database. This coding sequence was amplified by RT-PCR and cloned into the pcDNA 3.1(+) expression vector. The full length cDNA contains 957bp, corresponding to an open reading frame coding for 319 aa. The highest identity (84%) at the protein level was found with the Echinococcus multilocularis 17β-HSD although significant similarities were also found with other invertebrate and vertebrate 17β-HSD sequences. The T. solium Tsol-17βHSD belongs to the short-chain dehydrogenase/reductase (SDR) protein superfamily. HEK293T cells transiently transfected with Tsol17β-HSD induced expression of Tsol17β-HSD that transformed 3H-androstenedione into testosterone. In contrast, 3H-estrone was not significantly transformed into estradiol. In conclusion, T. solium cysticerci express a 17β-HSD that catalyzes the androgen reduction. The enzyme belongs to the short chain dehydrogenases/reductase family and shares motifs and activity with the type 3 enzyme of some other species.

Nanodomain induced anomalous magnetic and electronic transport properties of LaBaCo2O5.5+δ highly epitaxial thin films

A giant magnetoresistance effect (∼46% at 20 K under 7 T) and anomalous magnetic properties were found in a highly epitaxial double perovskite LaBaCo₂O_5.5+δ (LBCO) thin film on (001) MgO. Aberration-corrected Electron Microscopy and related analytical techniques were employed to understand the nature of these unusual physical properties. The as-grown film is epitaxial with the c-axis of the LBCO structure lying in the film plane and with an interface relationship given by (100)_LBCO || (001)_MgO and [001]_LBCO || [100]_MgO or [010]_MgO. Orderly oxygen vacancies were observed by line profile electron energy loss spectroscopy and by atomic resolution imaging. Especially, oxygen vacancy and nanodomain structures were found to have a crucial effect on the electronic transport and magnetic properties.

[Detection of tumors in the central zone of the prostate with 11C-Choline PET/CT]

Prostate tumors originate 68% in the peripheral region and 24% in the transitional region where tumors originating in the central zone are rare (8%). However, diagnosis of the tumors in the central zone is important since they exhibit greater aggressiveness conditioned by their location and different biological behavior. Magnetic resonance imaging shows problems in identifying lesions in the central prostate zone, since this region has a heterogeneous signal, mainly after the primary treatment. Ultrasound guided sextant biopsy shows a negative result in 28% of prostate tumors. Therefore, it is advisable to repeat or even to perform saturation biopsies. We present two patients, one of them with suspected biochemical prostate cancer and one with biochemical recurrence after radical treatment. In both, (11)C-Choline PET/CT allowed detection of the tumor focus in the central zone of the prostate, with negative complementary diagnostic test and biopsies.

Determination of the surface morphology of gold-decahedra nanoparticles using an off-axis electron holography dual-lens imaging system

The purpose of this paper is to show surface irregularities in gold decahedra nanoparticles extracted by using off-axis electron holography in a JEOL ARM 200F microscope. Electron holography has been used in a dual-lens system within the objective lenses: main objective lens and objective minilens. Parameters such as biprism voltage, fringe spacing (σ), fringe width (W) and optimum fringe contrast have been calibrated. The reliability of the transmission electron microscope performance with these parameters was carried out through a plug-in in the Digital-Micrograph software, which considers the mean inner potential within the particle leading a precise determination of the morphological surface of decahedral nanoparticles obtained from the reconstructed unwrapped phase and image processing. We have also shown that electron holography has the capability to extract information from nanoparticle shape that is currently impossible to obtain with any other electron microscopy technique.

[Detection of second tumors in 11C-choline PET/CT studies performed due to biochemical recurrence of prostate cancer]

Early localization of biochemical recurrence in patients after radical treatment of prostate cancer is a widely accepted clinical indication of (11)C-choline PET/CT. Its widespread clinical use has prompted the depiction of incidentalomas, unusual sites of metastatic lesions, as well as false positive and negative cases. Over the last 6 years, a total of 454 (11)C-choline PET/CT studies have been performed in our institution to locate biochemical recurrence of patients with prostate cancer. With these studies, a second neoplasm has been found in 7 patients (1.54%): 3 lung, 2 colorectal, 1 esophagus and 1 esophageal junction, respectively. Although the clinical usefulness of this technique for detecting cancer lesions other than prostate origin is known for those patients who undergo this technique in the accepted indication, the diagnosis of a second tumor has a significant impact on their therapeutic management.

Comment on "A bacterium that can grow by using arsenic instead of phosphorus"

Wolfe-Simon et al. (Research Articles, 3 June 2011, p. 1163; published online 2 December 2010) argued that the bacterial strain GFAJ-1 can vary the elemental composition of its biomolecules by substituting arsenic for phosphorus. Although their data show that GFAJ-1 is an extraordinary extremophile, consideration of arsenate redox chemistry undermines the suggestion that arsenate can replace the physiologic functions of phosphate.

Polymorphous silicon thin films obtained by plasma-enhanced chemical vapor deposition using dichlorosilane as silicon precursor

Polymorphous silicon thin films (pm-Si) have been deposited from mixtures of dichlorosilane and hydrogen, using argon as the diluting gas by plasma-enhanced chemical vapor deposition. The deposition conditions were chosen to simultaneously obtain both Si nanocrystallites and an amorphous silicon matrix in the as-grown samples. High resolution transmission electron microscopy studies show the crystallinity of Si domains whose dimensions are in the interval of 2-14 nm. The surface passivation state of the silicon nanocrystals was inferred from Fourier transform infrared spectroscopy analysis. Two optical absorption edges, corresponding to the amorphous matrix and the Si nanocrystals, were observed for all the pm-Si thin films. Intense visible photoluminescence was observed for the as-grown samples. The possibility of using these thin films for the down-conversion effect in silicon solar cells is discussed.

Production and characterization of pure Clostridium spore suspensions

AIMS

A general protocol was derived for optimizing the production of pure, high concentration Clostridium endospore suspensions.

METHODS AND RESULTS

Two sporulation methods were developed that yielded high concentrations of notably pure Clostridium sporogenes, C. hungatei and C. GSA-1 (Greenland ice core isolate) spore suspensions (10 ml of 10(9) spores ml(-1) with >99% purity each). Each method was derived by evaluating combinations of three sporulation conditions, including freeze drying of inocula, heat shock treatment of cultures, and subsequent incubation at suboptimal temperatures that yielded the highest percentage of sporulation. Pure spore suspensions were characterized in terms of dipicolinic acid content, culturability, decimal reduction time (D) value for heat inactivation (100 degrees C) and hydrophobicity.

CONCLUSIONS

While some Clostridium species produce a high percentage of spores with heat shock treatment and suboptimal temperature incubation, other species require the additional step of freeze drying the inocula to achieve a high percentage of sporulation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Pure Clostridium spore suspensions are required for investigating species of medical and environmental importance. Defining the conditions for optimal spore production also provides insight into the underlying mechanisms of Clostridium sporulation.

Taenia crassiceps: chloride currents expressed in Xenopus oocytes upon injection of mRNA of cysticerci (WFU strain) isolated from mice

To study the properties of ion channels of the tapeworm Taenia crassiceps, mRNA was isolated from cysticerci and injected into mature oocytes of the frog Xenopus laevis and ion currents were recorded four days after injection with the two-electrode voltage clamp technique. Oocytes injected with mRNA of T. crassiceps expressed outward currents (I(TC)) that activated instantly after onset of the test pulse, followed by a slow inactivation at potentials over +40 mV, with a reversal potential of -23.2+/-5 mV. They were not affected by changes on monovalent cationic composition of external media, but replacement of external chloride by gluconate shifted significantly the reversal potential, suggesting that I(TC) are anion currents, with a permeability sequence of NO3->Cl(-)>I(-)>>Gluconate. These currents were sensitive to changes of external pH but not to hypotonic challenges. They were significantly inhibited by DIDS, NPPB and Niflumic acid, but not by 9-anthracene. These results suggest that I(TC) are the result of expression of anion channels from the tapeworm T. crassiceps.

Saccular aneurysms of the extracranial internal carotid artery. Experience and review of the literature

The aim of this study was to describe the surgical technique employed and our results in the treatment of saccular aneurysms of the internal carotid artery at the extracranial level. We describe 3 cases of patients with saccular aneurysms of the extracranial internal carotid who underwent surgery at our unit within the last 3 years. We report on indications for treatment, surgical technique and results in terms of morbidity-mortality and also review the pertinent literature. Surgical treatment was indicated on the grounds of the patients being symptomatic: 2 had a history of cerebral ischemia, and 1 showed local compression symptoms. The surgical approach was presternocleidomastoid cervicotomy extended distally, and in 2 patients was accompanied by nasotracheal intubation to achieve adequate exposure. In 2 cases, we performed an aneurysmectomy with end-to-end anastomosis. In the third patient, the aneurysm neck was ligated from within the sac followed by aneurysmectomy. There was no mortality or neurological morbidity (local or general). The patients remain free from neurological symptoms with a patent carotid axis. Our clinical experience suggests that, despite the anatomically unfavorable location of this type of aneurysm and the greater complexity of the surgical technique, this patient group can be effectively treated. The frequent presence of an elongated carotid axis and an aneurysmal neck means the surgeon can easily restore arterial continuity by direct procedures.

Recurrent Carotid Artery Stenosis Following Endarterectomy: Natural History and Risk Factors

OBJECTIVES

To establish the incidence of restenosis (RES) following carotid endarterectomy (CEA) and evaluate clinical and technical factors related to its development.

DESIGN

Prospective non-randomised cohort study.

PATIENTS AND METHODS

Two hundred and twenty-four patients with 243 CEA between May 1998 and December 2002, were subjected to clinical and haemodynamic follow-up, median follow-up 23 months (1-56). There was selective use of a shunt (17.3%) and patch (61.7%). RES (> or =50%) and severe restenosis, > or =70%, (sRES) were defined as peak systolic velocities of > or =150 and > or =300cm/s (or > or =250cm/s with diastolic velocity >100cm/s), respectively. Rates of RES, symptom development and mortality were analysed using Kaplan-Meier curves. Cox's regression model (hazards ratio/95% CI) was used to evaluate prognostic factors.

RESULTS

We detected 13 sRES (5.3%) (median time 6.1 months) and 30 (12.3%) moderate stenosis (mRES) (median time 3.7 months). Cumulative freedom from sRES at 23 months was 94.2%. Five sRES detected in the first 45 days after the procedure were deemed to be residual restenosis (rRES). Five (38.4%) sRES were symptomatic, 15.3% progressed to occlusion. Patient survival was 98.0 and 96.4% at 12 and 24 months, respectively. Independent risk factors for sRES: female sex (HR: 3.3, 95% CI 1.1-10 p=0.04) and diabetes (HR: 4.5, 95% CI 1.4-13.9 p=0.008).

CONCLUSIONS

Carotid restenosis appears early, is usually low-grade and mostly asymptomatic. Although few stenoses progress to occlusion, women and diabetic patients were at highest risk.

[Percutaneous embolization of non-functioning renal graft as therapeutic alternative to surgical transplantectomy]

OBJECTIVE

To analyze the indications, results and complications of embolisation of a non-tolerated, non-functioning renal graft with regards to surgical transplantectomy.

MATERIAL AND METHODS

Between 1990 and 1998, 55 patients with failed renal graft were studied. Patients had undergone either subcapsular transplantectomy (23 patients) or percutaneous embolisation of allograft (32 patients). Mean age in both groups was 40.9 +/- 3.14 and 42 +/- 2.45 years respectively. After start of dialysis, the graft was left in situ for an average of 10.2 (+/- 11.2) and 9.9 (+/- 6.5) months. Hospital stay, occurrence of complications from the technique used, and results were compared.

RESULTS

Post-embolisation syndrome (high temperature for 2 to 5 days) was seen in 59% cases. No major complications secondary to embolization were seen, whereas 13% subcapsular nephrectomies had complications that required re-operation. Hospital stay was shorter (p > 0.005) in embolized patients than in those undergoing surgery. Sings and symptoms of intolerance disappears in 84.4% embolizations. Results were unsuccessful in 5 grafts (15.6%) undergoing embolisation, which resulted in deferred subcapsular transplantectomy.

CONCLUSIONS

Long-term, embolization shows acceptable control over the signs and symptoms of intolerance and involves less morbidity than transplantectomy. Surgery is useful when intolerance persists after one or more embolizations. Because of its features of safety and effectiveness, embolisation should be a choice treatment in selected cases.

Impact of induced aniseikonia on stereopsis with random-dot stereogram

In this work, we evaluate the impact of induced aniseikonia on stereopsis. For this, we determined the disparity range (maximum disparity), a parameter related to the size of the physical region that can be perceived stereoscopically. A significant decline in the disparity range was detected with aniseikonia induced by size lenses of 3% for five of the seven observers tested; 5% was necessary for the other two observers. The data indicate the influence of aniseikonia in stereopsis and the need to minimize such impact. These results may be useful in surgical processes such as the correction of pseudophakic patients and refractive surgery in which aniseikonia can be induced to alter the binocular function of the patient.

Nanocrystalline metal oxides as unique chemical reagents/sorbents

A new family of porous inorganic solids based on nanocrystalline metal oxides is discussed. These materials, made up of 4-7 nm MgO, CaO, Al2O3, ZnO, and others, exhibit unparalleled destructive adsorption properties for acid gases, polar organics, and even chemical/biological warfare agents. These unique sorption properties are due to nanocrystal shape, polar surfaces, and high surface areas. Free-flowing powders or consolidated pellets are effective, and pore structure can be controlled by consolidation pressures. Chemical properties can be adjusted by choice of metal oxide as well as by incorporating other oxides as monolayer films.

Spondyloarthropathy presenting as a polymyalgia rheumatica-like syndrome

Two female patients, aged 57 and 58 year-old presented with pain and stiffness in shoulder and/or pelvic girdles and a high ESR, suggesting polymyalgia rheumatica (PMR). The lack of response to low dose of steroids prompted us to reconsider this diagnosis and, after a careful evaluation and taking into account past clinical history, a final diagnosis of spondyloarthropathy (SpA) was made. The clinical spectrum of late SpA is heterogeneous, and in some instances may present as a polymyalgia-like syndrome.

K+ channel subunit isoforms with divergent carboxy-terminal sequences carry distinct membrane targeting signals

Kv3 K+ channel genes encode multiple products by alternative splicing of 3' ends resulting in the expression of K+ channel proteins that differ only in their C-termini. This divergence does not affect the electrophysiological properties of the channels expressed by these proteins. A similar alternative splicing with unknown function is seen in K+ channel genes of other families. We have investigated the possibility that the alternative splicing serves to generate channel subunits with different membrane targeting signals by examining the sorting behavior of three alternatively-spliced Kv3.2 isoforms when expressed in polarized MDCK cells. Two Kv3.2 proteins, Kv3.2b and Kv3.2c were expressed predominantly in the apical membrane, while Kv3.2a was localized mainly to the basolateral side (thought to be equivalent to the axonal and somatodendritic compartments in neurons, respectively). The Kv3.2 mRNA transcripts used in these studies are identical except for their 3' sequence, encoding the extreme C-terminal domain of the protein and the 3'UTR of the mRNA. However, the proteins achieve the same localizations in MDCK cells when expressed from constructs containing or lacking the 3'UTR, indicating that the differential localization is due to targeting signals present in the C' terminal domain of the protein. These results suggest that the alternative splicing of Kv3 genes is involved in channel localization. Since the precise localization of any given ion channel on the neuronal surface has significant functional implications, the results shown here suggest an important function for the alternative splicing of 3' ends seen in many K+ channel genes.

Biochemical markers of bone turnover in Camurati-Engelmann disease: a report on four cases in one family

Moderate increases in "classical" biochemical markers of bone turnover have been described only in some patients with Camurati-Engelmann disease. However, the determination of the following "new" markers has not been previously performed: serum osteocalcin (BGP), bone alkaline phosphatase (BAP), carboxyterminal propeptide of type I procollagen (PICP), aminoterminal propeptide of type I procollagen (PINP), tartrate-resistant acid phosphatase (TRAP), telopeptide carboxyterminal of type I collagen (ICTP), urinary pyridinoline (PYR), crosslinked N-telopeptides of type I collagen (NTX), and Crosslaps (CL). Such a determination may improve the evaluation of the disease activity. To evaluate the usefulness of biochemical markers of bone turnover reflecting Camurati-Engelmann disease activity we measured the levels of all these markers in four affected patients. The results were compared with bone scintigraphic indices of disease activity. Except for PICP and TRAP, bone formation and resorption markers were abnormal in all patients and were related to bone scan indices of disease activity. Among the markers of bone formation PINP, BAP, and BGP showed the highest values, whereas NTX and CL were the most sensitive markers of bone resorption. These results suggest that the determination of NTX or CL, and PINP or either BAP and BGP, associated with bone scan evaluation, provides the best assessment of Camurati-Engelmann disease activity.

[The role of cellular contacts in the recovery of the ion channels of epithelial cell membranes]

Cationic currents in mature MDCK cells are almost exclusively due to K+ channels. Harvesting with trypsin-EDTA destroys 80-90% of these channels. Upon replating, K+ currents recover in 12-20 h, by means a process that requires synthesis of proteins and of RNA. In the present work we demonstrate that this restoration depends on a Ca2+ activated-cell contact. Thus, cells in confluent monolayers bathed with 1.8 mM Ca2+ have a K+ current of 343 +/- 82 pA; confluent without Ca2+ have only 90 +/- 12 pA (27% of control; and without cell-cell contacts incubated with 1.8 mM Ca2+ (subconfl+Ca2+) have 104 +/- 21 pA (31% of control). This demonstration that the expression of K+ channels depends on Ca-activated cell-attaching molecules suggests that a molecule of the type of uvomorulin is involved.

Carpal tunnel syndrome heralding polymyalgia rheumatica

Presenting symptoms in polymyalgia rheumatica (PMR) may be atypical. We report herein two old females who developed a bilateral carpal tunnel syndrome several months before the typical symptoms of PMR appeared. In both patients the diagnosis of PMR was overlooked and a surgical release of the median nerve was performed. PMR should be considered in elderly people who develop an acute or subacute carpal tunnel syndrome.

G-protein-gated inward rectifier K+ channel proteins (GIRK1) are present in the soma and dendrites as well as in nerve terminals of specific neurons in the brain

G-protein-gated inward rectifier potassium (GIRK) channels are coupled to numerous neurotransmitter receptors in the brain and can play important roles in modulating neuronal function, depending on their localization in a given neuron. Site-directed antibodies to the extreme C terminus of GIRK1 (or KGA1), a recently cloned component of GIRK channels, have been used to determine the relative expression levels and distribution of the protein in different regions of the rat brain by immunoblot and immunohistochemical techniques. We report that the GIRK1 protein is expressed prominently in the olfactory bulb, hippocampus, dentate gyrus, neocortex, thalamus, cerebellar cortex, and several brain stem nuclei. In addition to the expected localization in somas and dendrites, where GIRK channels may mediate postsynaptic inhibition, GIRK1 proteins were also found in axons and their terminal fields, suggesting that GIRK channels can also modulate presynaptic events. Furthermore, the distribution of the protein to either somatodendritic or axonal-terminal regions of neurons varied in different brain regions, which would imply distinct functions of these channels in different neuronal populations. Particularly prominent staining of the cortical barrels of layer IV of the neocortex, and the absence of this staining with unilateral kainate lesions of the thalamus, suggest that the GIRK1 protein is expressed in thalamocortical nerve terminals in which GIRK channels may mediate the actions of mu opiate receptors.

Thalamocortical projections have a K+ channel that is phosphorylated and modulated by cAMP-dependent protein kinase

The finding that some K+ channel mRNAs are restricted to certain populations of neurons in the CNS suggests that there are K+ channels tailored to certain neuronal circuits. One such example are the transcripts from the KV3.2 gene, the majority of which are expressed in thalamic relay neurons. To gain insights into the specific roles of KV3.2 subunits, site specific antibodies were raised to determine their localization in thalamic relay neurons. Immunohistochemical and focal lesioning studies demonstrate that KV3.2 proteins are localized to the terminal fields of thalamocortical projections. It is also shown that KV3.2 channels expressed in vitro are strongly inhibited through phosphorylation by cAMP-dependent protein kinase (PKA). Channels containing KV3.1 subunits, which otherwise exhibit nearly identical electrophysiological properties in heterologous expression systems but have a different and less restricted pattern of expression in the CNS, are not affected by PKA. Therefore, this modulation might be associated with the specific roles of KV3.2 subunits. Furthermore, we demonstrate that KV3.2 proteins can be phosphorylated in situ by intrinsic PKA. KV3.2 subunits display properties and have a localization consistent with a role in the regulation of the efficacy of the thalamocortical synapse, and could thereby participate in the neurotransmitter-mediated control of functional states of the thalamocortical system associated with global states of awareness.

Expression of potassium channels in epithelial cells depends on calcium-activated cell-cell contacts

Harvesting MDCK cells with trypsin-EDTA reduces potassium currents (IK) to a mere 10%, presumably by hydrolysis of K+ channels, but replating at confluence restores them in 12-18 hr, through a process that requires transcription, translation and exocytic fusion of intracellular membrane vesicles to the plasma membrane (Ponce & Cereijido, 1991; Ponce et al., 1991a). In the present work we find that this restoration of IK also requires cell-cell contacts and the presence of 1.8 mM Ca2+. The role of extracellular Ca2+ may be substituted by 2.0 microM TRH, 10 nM PMA or 200 micrograms/ml DiC8. drugs that stimulate the system of phospholipase C (PLC) and protein kinase C (PKC). Conversely, the recovery of IK triggered by Ca-dependent contacts can be blocked by 110 microM neomycin, 2.0 microM H7, and 250 nM staurosporine, inhibitors of PLC and PKC. These results suggest that the expression of new K+ channels depends on Ca(2+)-activated contacts with neighboring cells and that the information is conveyed through PLC and PKC, a process in keeping with changes in its enzymatic activity and cellular distribution of PKC. Plasma membrane is also reduced and restored upon harvesting and replating, and depends on Ca(2+)-activated contracts. However, the effects of the chemicals tested on IK differ from the ones they elicit on the recovery of plasma membrane, suggesting that cells can independently regulate their population of K+ channels and the surface of their membrane.

Time-related changes in functional activity of mouse spermatozoa during in vitro or in vivo incubation

The kinetics of functional modifications during in vivo or in vitro incubation was studied in spermatozoa from Albino Swiss mice, obtained from cauda epididymis (E) or from uterus (U) or oviduct (O) post copulation (p.c.). Results clearly suggest that functional activity as reflected by measurements of motility, hypoosmotic swelling test and acrosome reaction differs according to the segments of the reproductive tract from which they were collected. The comparison of results obtained after equivalent periods of in vitro or in vivo incubation, shows that the time course of changes in sperm motility and percentage of swollen sperm is similar in both conditions. Since the percentage of acrosome-reacted gametes was higher in O, at all times scored, oviductal environment appeared to be capable of inducing this phenomenon. Our experimental conditions seemed to be adequate for completion of spermatozoa maturation and successful interaction between male and female gametes as reflected by the results of fertilization rate and embryo cleavage.