The effects of early pregnancy loss on health outcomes and health care utilization and costs

Objective

To evaluate the effects of early pregnancy loss on subsequent health care use and costs.

Data Sources

Linked administrative health databases from Manitoba, Canada.

Study Design

This was a population‐based cohort study. The exposure of interest was first recorded ectopic pregnancy or miscarriage (EPM). Outcomes included visits to all ambulatory care providers, family physicians (FPs), specialists, and hospitals, as well as the costs associated with these visits. We also assessed the impact of EPM on a global measure of health service utilization and the incidence and costs of psychotropic medications.

Data Collection/Extraction Methods

We identified women who experienced their first recorded loss (EPM) from 2003–2012 and created a propensity score model to match these women to women who experienced a live birth, with outcome measures available through 31 December 2014. We used a difference in differences approach with multivariable negative binomial models and generalized estimating equations (GEE) to assess the impact of EPM on the aforementioned health care utilization indicators.

Principal Findings

EPM was associated with a short‐term increase in visits to, and costs associated with, certain ambulatory care providers. These findings were driven in large part by increased visits/costs to FPs (rate difference [RD]: $19.92 [95% CI: $16.33, $23.51]) and obstetrician‐gynecologists (OB‐GYNs) (RD $9.41 [95% CI: $8.42, $10.40]) in the year immediately following the loss, excluding care associated with the loss itself. We also detected an increase in hospital stays and costs and a decrease in the use of psychotropic medications relative to matched controls.

Conclusion

Pregnancy loss may lead to subsequent increases in certain types of health care utilization. While the absolute costs associated with post‐EPM care are relatively small, the observed patterns of service utilization are informative for providers and policy makers seeking to support women following a loss.

Fluoroquinolone use for uncomplicated urinary tract infections in women: a retrospective cohort study

OBJECTIVES

The United States Food & Drug Administration released an advisory in 2016 that fluoroquinolones be relegated to second-line agents for uncomplicated urinary tract infections (UTIs) given reports of rare but serious side effects; similar warnings have followed from Health Canada and the European Medicines Agency. The objective was to determine whether alternative non-fluoroquinolone agents are as effective as fluoroquinolones in the treatment of UTIs.

METHODS

We conducted a retrospective population-based cohort study using administrative health data from six Canadian provinces. We identified women (n = 1 585 997) receiving antibiotic treatment for episodes of uncomplicated UTIs (n = 2 857 243) between January 1 2005 and December 31 2015. Clinical outcomes within 30 days from the initial antibiotic dispensation were compared among patients treated with a fluoroquinolone versus non-fluoroquinolone agents. High-dimensional propensity score adjustments were used to ensure comparable treatment groups and to minimize residual confounding.

RESULTS

Fluoroquinolone use for UTI declined over the study period in five of six Canadian provinces and accounted for 22.3-48.5% of treatments overall. The pooled effect across the provinces indicated that fluoroquinolones were associated with fewer return outpatient visits (OR 0.89, 95%CI 0.87-0.92), emergency department visits (OR 0.74, 95%CI 0.61-0.89), hospitalizations (OR 0.83, 95%CI 0.77-0.88), and repeat antibiotic dispensations (OR 0.77, 95%CI 0.75-0.80) within 30 days.

CONCLUSIONS

Fluoroquinolones are associated with improved clinical outcomes among women with uncomplicated UTIs. This benefit must be weighed against the risk of fluoroquinolone resistance and rare but serious fluoroquinolone side effects when selecting first-line treatment for these patients.

Estimating glomerular filtration rate in youth with obesity and type 2 diabetes: the iCARE study equation

BACKGROUND

The validity of pediatric estimated glomerular filtration rate equations (eGFRs) in early stages of CKD including hyperfiltration is unknown. The purpose of this study was to develop an eGFR equation for adolescents with obesity and type 2 diabetes (T2D).

METHODS

eGFRs were developed from iohexol-derived GFRs (iGFRs) in 26 overweight/obese (BMI > 85th percentile) youth and 100 with T2D from the iCARE (Improving renal Complications in Adolescents with T2D through REsearch) cohort. Twenty percent of the cohort was withheld as a validation dataset. Linear regression analyses were used to develop the best formula based on body size, sex, creatinine, urea, ± cystatin C. Comparable validity of commonly used eGFR equations was assessed.

RESULTS

Mean age 15.4 + 2.4 years, BMI Z-score 2.5 + 1.2, 61% female, and mean iGFR 129.0 + 27.7 ml/min/ 1.73 m². The best adjusted eGFR formula (ml/min/1.73 m²) was 50.7 × BSA^0.816 × (height (cm)/creatinine)^0.405 × 0.8994 if sex = female | 1 otherwise. It resulted in 53.8% of eGFRs within 10% of measured iGFR and 96.2% within 30%. Bland-Altman 95% limits of agreement in the external dataset were - 37.6 to 45.5 ml/min/1.73m² (bias = 3.96), and the correlation was 0.62. This equation performed better than all previously published creatinine-based eGFRs. cystatin C did not significantly improve results; however, some other cystatin C formulas also performed well.

CONCLUSIONS

The iCARE equation provides a more accurate creatinine-based eGFR in obese youth with and without T2D. Further studies are warranted to evaluate within-subject variability and applicability to lower GFRs and other populations.

AIF loss deregulates hematopoiesis and reveals different adaptive metabolic responses in bone marrow cells and thymocytes

Mitochondrial metabolism is a tightly regulated process that plays a central role throughout the lifespan of hematopoietic cells. Herein, we analyze the consequences of the mitochondrial oxidative phosphorylation (OXPHOS)/metabolism disorder associated with the cell-specific hematopoietic ablation of apoptosis-inducing factor (AIF). AIF-null (AIF-/Y ) mice developed pancytopenia that was associated with hypocellular bone marrow (BM) and thymus atrophy. Although myeloid cells were relatively spared, the B-cell and erythroid lineages were altered with increased frequencies of precursor B cells, pro-erythroblasts I, and basophilic erythroblasts II. T-cell populations were dramatically reduced with a thymopoiesis blockade at a double negative (DN) immature state, with DN1 accumulation and delayed DN2/DN3 and DN3/DN4 transitions. In BM cells, the OXPHOS/metabolism dysfunction provoked by the loss of AIF was counterbalanced by the augmentation of the mitochondrial biogenesis and a shift towards anaerobic glycolysis. Nevertheless, in a caspase-independent process, the resulting excess of reactive oxygen species compromised the viability of the hematopoietic stem cells (HSC) and progenitors. This led to the progressive exhaustion of the HSC pool, a reduced capacity of the BM progenitors to differentiate into colonies in methylcellulose assays, and the absence of cell-autonomous HSC repopulating potential in vivo. In contrast to BM cells, AIF-/Y thymocytes compensated for the OXPHOS breakdown by enhancing fatty acid β-oxidation. By over-expressing CPT1, ACADL and PDK4, three key enzymes facilitating fatty acid β-oxidation (e.g., palmitic acid assimilation), the AIF-/Y thymocytes retrieved the ATP levels of the AIF +/Y cells. As a consequence, it was possible to significantly reestablish AIF-/Y thymopoiesis in vivo by feeding the animals with a high-fat diet complemented with an antioxidant. Overall, our data reveal that the mitochondrial signals regulated by AIF are critical to hematopoietic decision-making. Emerging as a link between mitochondrial metabolism and hematopoietic cell fate, AIF-mediated OXPHOS regulation represents a target for the development of new immunomodulatory therapeutics.

RANK/RANKL/OPG Signalization Implication in Periodontitis: New Evidence from a RANK Transgenic Mouse Model

Periodontitis is based on a complex inflammatory over-response combined with possible genetic predisposition factors. The RANKL/RANK/OPG signaling pathway is implicated in bone resorption through its key function in osteoclast differentiation and activation, as well as in the inflammatory response. This central element of osteo-immunology has been suggested to be perturbed in several diseases, including periodontitis, as it is a predisposing factor for this disease. The aim of the present study was to validate this hypothesis using a transgenic mouse line, which over-expresses RANK (R^Tg) and develops a periodontitis-like phenotype at 5 months of age. R^Tg mice exhibited severe alveolar bone loss, an increased number of TRAP positive cells, and disorganization of periodontal ligaments. This phenotype was more pronounced in females. We also observed dental root resorption lacunas. Hyperplasia of the gingival epithelium, including Malassez epithelial rests, was visible as early as 25 days, preceding any other symptoms. These results demonstrate that perturbations of the RANKL/RANK/OPG system constitute a core element of periodontitis, and more globally, osteo-immune diseases.

Two-photon controlled sol–gel condensation for the microfabrication of silica based microstructures. The role of photoacids and photobases

Two-photon excitation of photobases is used to induce pH changes and control the condensation step of the sol–gel process at the focal point of a laser beam in a confocal configuration.

Intestinal invalidation of the glucose transporter GLUT2 delays tissue distribution of glucose and reveals an unexpected role in gut homeostasis

OBJECTIVE

Intestinal glucose absorption is orchestrated by specialized glucose transporters such as SGLT1 and GLUT2. However, the role of GLUT2 in the regulation of glucose absorption remains to be fully elucidated.

METHODS

We wanted to evaluate the role of GLUT2 on glucose absorption and glucose homeostasis after intestinal-specific deletion of GLUT2 in mice (GLUT2^ΔIEC mice).

RESULTS

As anticipated, intestinal GLUT2 deletion provoked glucose malabsorption as visualized by the delay in the distribution of oral sugar in tissues. Consequences of intestinal GLUT2 deletion in GLUT2^ΔIEC mice were limiting body weight gain despite normal food intake, improving glucose tolerance, and increasing ketone body production. These features were reminiscent of calorie restriction. Other adaptations to intestinal GLUT2 deletion were reduced microvillus length and altered gut microbiota composition, which was associated with improved inflammatory status. Moreover, a reduced density of glucagon-like peptide-1 (GLP-1) positive cells was compensated by increased GLP-1 content per L-cell, suggesting a preserved enteroendocrine function in GLUT2^ΔIEC mice.

CONCLUSIONS

Intestinal GLUT2 modulates glucose absorption and constitutes a control step for the distribution of dietary sugar to tissues. Consequently, metabolic and gut homeostasis are improved in the absence of functional GLUT2 in the intestine, thus mimicking calorie restriction.

CD47 agonist peptides induce programmed cell death in refractory chronic lymphocytic leukemia B cells via PLCγ1 activation: evidence from mice and humans

BACKGROUND

Chronic lymphocytic leukemia (CLL), the most common adulthood leukemia, is characterized by the accumulation of abnormal CD5+ B lymphocytes, which results in a progressive failure of the immune system. Despite intense research efforts, drug resistance remains a major cause of treatment failure in CLL, particularly in patients with dysfunctional TP53. The objective of our work was to identify potential approaches that might overcome CLL drug refractoriness by examining the pro-apoptotic potential of targeting the cell surface receptor CD47 with serum-stable agonist peptides.

METHODS AND FINDINGS

In peripheral blood samples collected from 80 patients with CLL with positive and adverse prognostic features, we performed in vitro genetic and molecular analyses that demonstrate that the targeting of CD47 with peptides derived from the C-terminal domain of thrombospondin-1 efficiently kills the malignant CLL B cells, including those from high-risk individuals with a dysfunctional TP53 gene, while sparing the normal T and B lymphocytes from the CLL patients. Further studies reveal that the differential response of normal B lymphocytes, collected from 20 healthy donors, and leukemic B cells to CD47 peptide targeting results from the sustained activation in CLL B cells of phospholipase C gamma-1 (PLCγ1), a protein that is significantly over-expressed in CLL. Once phosphorylated at tyrosine 783, PLCγ1 enables a Ca2+-mediated, caspase-independent programmed cell death (PCD) pathway that is not down-modulated by the lymphocyte microenvironment. Accordingly, down-regulation of PLCγ1 or pharmacological inhibition of PLCγ1 phosphorylation abolishes CD47-mediated killing. Additionally, in a CLL-xenograft model developed in NOD/scid gamma mice, we demonstrate that the injection of CD47 agonist peptides reduces tumor burden without inducing anemia or toxicity in blood, liver, or kidney. The limitations of our study are mainly linked to the affinity of the peptides targeting CD47, which might be improved to reach the standard requirements in drug development, and the lack of a CLL animal model that fully mimics the human disease.

CONCLUSIONS

Our work provides substantial progress in (i) the development of serum-stable CD47 agonist peptides that are highly effective at inducing PCD in CLL, (ii) the understanding of the molecular events regulating a novel PCD pathway that overcomes CLL apoptotic avoidance, (iii) the identification of PLCγ1 as an over-expressed protein in CLL B cells, and (iv) the description of a novel peptide-based strategy against CLL.

From gold nanobipyramids to nanojavelins for a precise tuning of the plasmon resonance to the infrared wavelengths: experimental and theoretical aspects

Anisotropic gold nanoparticles and in particular with shapes exhibiting tips are known to present an extremely strong localized electromagnetic field. This field is mostly located at the top of the tips and can be used in various optical applications. Moreover, as a consequence of their anisotropy, they present two plasmon resonance bands corresponding to the transverse and longitudinal resonance modes. Tuning the aspect ratio it becomes possible to display SPR bands near the near infrared region. This was particularly investigated in the case of nanorods and also for bipyramids. In this paper we report a high yield synthesis approach that allows one to precisely control the aspect ratio of bipyramids and to elongate the structure until they adopt a javelin-like aspect. We were able to prepare nano-javelins with surface plasmon resonances up to 1850 nm, opening important perspectives in terms of optical applications in the NIR and IR regions. The synthetic methods are fully reported and the optical properties were correlated with the theoretical approach, taking into consideration not only the aspect ratio but also the truncation of the nano-objects.

Long-term benefits of full-day kindergarten: a longitudinal population-based study

In the first longitudinal, population-based study of full-day kindergarten (FDK) outcomes beyond primary school in Canada, we used linked administrative data to follow 15 kindergarten cohorts (n ranging from 112 to 736) up to grade 9. Provincial assessments conducted in grades 3, 7, and 8 and course marks and credits earned in grade 9 were compared between FDK and half-day kindergarten (HDK) students in both targeted and universal FDK programmes. Propensity score matched cohort and stepped-wedge designs allowed for stronger causal inferences than previous research on FDK. We found limited long-term benefits of FDK, specific to the type of programme, outcomes examined, and subpopulations. FDK programmes targeted at low-income areas showed long-term improvements in numeracy for lower income girls. Our results suggest that expectations for wide-ranging long-term academic benefits of FDK are unwarranted.

Risk of suicide and suicide attempts associated with physical disorders: a population-based, balancing score-matched analysis

BACKGROUND

The association between physical disorders and suicide remains unclear. The aim of this study was to examine the relationship between physical disorders and suicide after accounting for the effects of mental disorders.

METHOD

Individuals who died by suicide (n = 2100) between 1996 and 2009 were matched 3:1 by balancing score to general population controls (n = 6300). Multivariate conditional logistic regression compared the two groups across physician-diagnosed physical disorders [asthma, chronic obstructive pulmonary disease (COPD), ischemic heart disease, hypertension, diabetes, cancer, multiple sclerosis and inflammatory bowel disease], adjusting for mental disorders and co-morbidity. Secondary analyses examined the risk of suicide according to time since first diagnosis of each physical disorder (1-90, 91-364, ⩾ 365 days). Similar analyses also compared individuals with suicide attempts (n = 8641) to matched controls (n = 25 923).

RESULTS

Cancer was associated with increased risk of suicide [adjusted odds ratio (AOR) 1.40, 95% confidence interval (CI) 1.03-1.91, p < 0.05] even after adjusting for all mental disorders. The risk of suicide with cancer was particularly high in the first 90 days after initial diagnosis (AOR 4.10, 95% CI 1.71-9.82, p < 0.01) and decreased to non-significance after 1 year. Women with respiratory diseases had elevated risk of suicide whereas men did not. COPD, hypertension and diabetes were each associated with increased odds of suicide attempts in adjusted models (AORs ranged from 1.20 to 1.73).

CONCLUSIONS

People diagnosed with cancer are at increased risk of suicide, especially in the 3 months following initial diagnosis. Increased support and psychiatric involvement should be considered for the first year after cancer diagnosis.

Asporin and the mineralization process in fluoride-treated rats

Microarray analysis of odontoblastic cells treated with sodium fluoride has identified the asporin gene as a fluoride target. Asporin is a member of the small leucine-rich repeat proteoglycan/protein (SLRP) family that is believed to be important in the mineralization process. In this study, asporin expression and distribution were investigated by systematic analysis of dentin and enamel, with and without fluoride treatment. Specific attention was focused on a major difference between the two mineralized tissues: the presence of a collagenous scaffold in dentin, and its absence in enamel. Normal and fluorotic, continually growing incisors from Wistar rats treated with 2.5 to 7.5 mM sodium fluoride (NaF) were studied by immunochemistry, in situ hybridization, Western blotting, and RT-qPCR. Asporin was continuously expressed in odontoblasts throughout dentin formation as expected. Asporin was also found, for the first time, in dental epithelial cells, particularly in maturation-stage ameloblasts. NaF decreased asporin expression in odontoblasts and enhanced it in ameloblasts, both in vivo and in vitro. The inverse response in the two cell types suggests that the effector, fluoride, is a trigger that elicits a cell-type-specific reaction. Confocal and ultrastructural immunohistochemistry evidenced an association between asporin and type 1 collagen in the pericellular nonmineralized compartments of both bone and dentin. In addition, transmission electron microscopy revealed asporin in the microenvironment of all cells observed. Thus, asporin is produced by collagen-matrix-forming and non-collagen-matrix-forming cells but may have different effects on the mineralization process. A model is proposed that predicts impaired mineral formation associated with the deficiency and excess of asporin.

Autophagosomes contribute to intracellular lipid distribution in enterocytes

Delivery of alimentary lipids induces immediate autophagic response in enterocytes. Forming autophagosomes are recruited to the ER membrane, where they capture nascent lipid droplets and later fuse with lysosomes, illustrating for the first time the role of autophagy in neutral-lipid distribution in enterocytes.

Enterocytes, the intestinal absorptive cells, have to deal with massive alimentary lipids upon food consumption. They orchestrate complex lipid-trafficking events that lead to the secretion of triglyceride-rich lipoproteins and/or the intracellular transient storage of lipids as lipid droplets (LDs). LDs originate from the endoplasmic reticulum (ER) membrane and are mainly composed of a triglyceride (TG) and cholesterol-ester core surrounded by a phospholipid and cholesterol monolayer and specific coat proteins. The pivotal role of LDs in cellular lipid homeostasis is clearly established, but processes regulating LD dynamics in enterocytes are poorly understood. Here we show that delivery of alimentary lipid micelles to polarized human enterocytes induces an immediate autophagic response, accompanied by phosphatidylinositol-3-phosphate appearance at the ER membrane. We observe a specific and rapid capture of newly synthesized LD at the ER membrane by nascent autophagosomal structures. By combining pharmacological and genetic approaches, we demonstrate that autophagy is a key player in TG targeting to lysosomes. Our results highlight the yet-unraveled role of autophagy in the regulation of TG distribution, trafficking, and turnover in human enterocytes.

Fracture path in an anisotropic material in the light of a friction experiment

A slider is pulled by means of a flexible link on a flat solid surface which exhibits anisotropic frictional properties. The resulting trajectory of the slider is assessed experimentally. First, we check that the experimental results are in excellent agreement with a theoretical description of the problem based on an expression of the frictional forces. Second, we point out that the trajectory of the slider can be recovered by the use of a "maximum of energy release rate" criterion which is generally used to predict the path of a fracture even if the validity of the principle is difficult to verify in the latter complex systems.

Mutations in SLC2A2 gene reveal hGLUT2 function in pancreatic β cell development

The structure-function relationships of sugar transporter-receptor hGLUT2 coded by SLC2A2 and their impact on insulin secretion and β cell differentiation were investigated through the detailed characterization of a panel of mutations along the protein. We studied naturally occurring SLC2A2 variants or mutants: two single-nucleotide polymorphisms and four proposed inactivating mutations associated to Fanconi-Bickel syndrome. We also engineered mutations based on sequence alignment and conserved amino acids in selected domains. The single-nucleotide polymorphisms P68L and T110I did not impact on sugar transport as assayed in Xenopus oocytes. All the Fanconi-Bickel syndrome-associated mutations invalidated glucose transport by hGLUT2 either through absence of protein at the plasma membrane (G20D and S242R) or through loss of transport capacity despite membrane targeting (P417L and W444R), pointing out crucial amino acids for hGLUT2 transport function. In contrast, engineered mutants were located at the plasma membrane and able to transport sugar, albeit with modified kinetic parameters. Notably, these mutations resulted in gain of function. G20S and L368P mutations increased insulin secretion in the absence of glucose. In addition, these mutants increased insulin-positive cell differentiation when expressed in cultured rat embryonic pancreas. F295Y mutation induced β cell differentiation even in the absence of glucose, suggesting that mutated GLUT2, as a sugar receptor, triggers a signaling pathway independently of glucose transport and metabolism. Our results describe the first gain of function mutations for hGLUT2, revealing the importance of its receptor versus transporter function in pancreatic β cell development and insulin secretion.

Requirement of cellular prion protein for intestinal barrier function and mislocalization in patients with inflammatory bowel disease

BACKGROUND & AIMS

Cell adhesion is one function regulated by cellular prion protein (PrP(c)), a ubiquitous, glycosylphosphatidylinositol-anchored glycoprotein. PrP(c) is located in cell-cell junctions and interacts with desmosome proteins in the intestinal epithelium. We investigated its role in intestinal barrier function.

METHODS

We analyzed permeability and structure of cell-cell junctions in intestine tissues from PrP(c) knockout (PrP(c-/-)) and wild-type mice. PrP(c) expression was knocked down in cultured human Caco-2/TC7 enterocytes using small hairpin RNAs. We analyzed colon samples from 24 patients with inflammatory bowel disease (IBD).

RESULTS

Intestine tissues from PrP(c-/-) mice had greater paracellular permeability than from wild-type mice (105.9 ± 13.4 vs 59.6 ± 10.1 mg/mL fluorescein isothiocyanate-dextran flux; P < .05) and impaired intercellular junctions. PrP(c-/-) mice did not develop spontaneous disease but were more sensitive than wild-type mice to induction of colitis with dextran sulfate (32% mortality vs 4%, respectively; P = .0033). Such barrier defects were observed also in Caco-2/TC7 enterocytes following PrP(c) knockdown; the cells had increased paracellular permeability (1.5-fold over 48 hours; P < .001) and reduced transepithelial electrical resistance (281.1 ± 4.9 vs 370.6 ± 5.7 Ω.cm(2); P < .001). Monolayer shape and cell-cell junctions were altered in cultures of PrP(c) knockdown cells; levels of E-cadherin, desmoplakin, plakoglobin, claudin-4, occludin, zonula occludens 1, and tricellulin were decreased at cell contacts. Cell shape and junctions were restored on PrP(c) re-expression. Levels of PrP(c) were decreased at cell-cell junctions in colonic epithelia from patients with Crohn's disease or ulcerative colitis.

CONCLUSIONS

PrP(c) regulates intestinal epithelial cell-cell junctions and barrier function. Its localization is altered in colonic epithelia from patients with IBD, supporting the concept that disrupted barrier function contributes to this disorder.

The lipoatrophic caveolin-1 deficient mouse model reveals autophagy in mature adipocytes

Adipose tissue lipoatrophy caused by caveolin gene deletion in mice is not linked to defective adipocyte differentiation. We show that adipose tissue development cannot be rescued by endothelial specific caveolin-1 re-expression, indicating primordial role of caveolin in mature adipocytes. Partial or total caveolin deficiency in adipocytes induced broad protein expression defects, including but not limited to previously described downregulation of insulin receptor. Global alterations in protein turnover, and accelerated degradation of long-lived proteins were found in caveolin-deficient adipocytes. Lipidation of endogenous LC3 autophagy marker and distribution of GFP-LC3 into aggregates demonstrated activated autophagy in the absence of caveolin-1 in adipocytes. Furthermore, electron microscopy revealed autophagic vacuoles in caveolin-1 deficient but not control adipocytes. Surprisingly, significant levels of lipidated LC3-II were found around lipid droplets of normal adipocytes, maintained in nutrient-rich conditions or isolated from fed mice, which do not display autophagy. Altogether, these data indicate that caveolin deficiency induce autophagy in adipocytes, a feature that is not a physiological response to fasting in normal fat cells. This likely resulted from defective insulin and lipolytic responses that converge in chronic nutrient shortage in adipocytes lacking caveolin-1. This is the first report of a pathological situation with autophagy as an adaptative response to adipocyte failure.

Are the Amygdaloid Projections to the Hypothalamic Ventromedial Nucleus Involved in Estrous Rhythm Regulation in the Female Rat?

The aim of this investigation was to determine whether the corticomedial amygdaloid nucleus (CMA) and its projections to the hypothalamic ventromedial nucleus (VMN) were involved in the regulation of estrous rhythm by the VMN in the rat. It is known (Carrer et al., 1973-1974) that partial VMN lesions caused the occurrence of either 5-day or alternate 4- or 5-day cycles in about 50% of 4-day cyclic female rats and that large lesions induced cycle prolongation in most of the operated animals while hypothalamic dorsomedial nucleus (DMN) lesions left estrous rhythm unmodified. CMA lesions in 4-day cyclic female rats caused the occurrence of either 5-day or alternate cycles with sequence of 4, 5, 4 days, more frequently than in their sham operated counterparts (15/20 vs 3/20). Stria terminalis (ST) lesions placed at its emergence from the CMA or at its horizontal course over the internal capsule induced a higher proportion (10/14 and 9/16, respectively) of females to display changes in cycle duration than did sham operated and unoperated controls as well (10/32 and 7/29, respectively). Combined partial VMN and ST lesions resulted in a 24 hours cycle prolongation or alternate 4- and 5-day cycles in a greater number of females than in those bearing small VMN lesions only (15/18 vs 22/40). A noticeable proportion of CMA, ST and ST + small VMN lesioned females offered more or less prolonged diestrous periods immediately following surgery before resuming estrous cyclicity. It was suggested that the CMA neurons which project fibers to the VMN via the ST are implicated in estrous rhythm regulation in the rat.

Sensing of dietary lipids by enterocytes: a new role for SR-BI/CLA-1

Background

The intestine is responsible for absorbing dietary lipids and delivering them to the organism as triglyceride-rich lipoproteins (TRL). It is important to determine how this process is regulated in enterocytes, the absorptive cells of the intestine, as prolonged postprandial hypertriglyceridemia is a known risk factor for atherosclerosis. During the postprandial period, dietary lipids, mostly triglycerides (TG) hydrolyzed by pancreatic enzymes, are combined with bile products and reach the apical membrane of enterocytes as postprandial micelles (PPM). Our aim was to determine whether these micelles induce, in enterocytes, specific early cell signaling events that could control the processes leading to TRL secretion.

Methodology/Principal Findings

The effects of supplying PPM to the apex of Caco-2/TC7 enterocytes were analyzed. Micelles devoid of TG hydrolysis products, like those present in the intestinal lumen in the interprandial period, were used as controls. The apical delivery of PPM specifically induced a number of cellular events that are not induced by interprandial micelles. These early events included the trafficking of apolipoprotein B, a structural component of TRL, from apical towards secretory domains, and the rapid, dose-dependent activation of ERK and p38MAPK. PPM supply induced the scavenger receptor SR-BI/CLA-1 to cluster at the apical brush border membrane and to move from non-raft to raft domains. Competition, inhibition or knockdown of SR-BI/CLA-1 impaired the PPM-dependent apoB trafficking and ERK activation.

Conclusions/Significance

These results are the first evidence that enterocytes specifically sense postprandial dietary lipid-containing micelles. SR-BI/CLA-1 is involved in this process and could be a target for further study with a view to modifying intestinal TRL secretion early in the control pathway.

Adaptation of enterocytic Caco-2 cells to glucose modulates triacylglycerol-rich lipoprotein secretion through triacylglycerol targeting into the endoplasmic reticulum lumen

Enterocytes are responsible for the absorption of dietary lipids, which involves TRL [TG (triacylglycerol)-rich lipoprotein] assembly and secretion. In the present study, we analysed the effect on TRL secretion of Caco-2 enterocyte adaptation to a differential glucose supply. We showed that TG secretion in cells adapted to a low glucose supply for 2 weeks after confluence was double that of control cells maintained in high-glucose-containing medium, whereas the level of TG synthesis remained similar in both conditions. This increased secretion resulted mainly from an enlargement of the mean size of the secreted TRL. The increased TG availability for TRL assembly and secretion was not due to an increase in the MTP (microsomal TG transfer protein) activity that is required for lipid droplet biogenesis in the ER (endoplasmic reticulum) lumen, or to the channelling of absorbed fatty acids towards the monoacylglycerol pathway for TG synthesis. Interestingly, by electron microscopy and subcellular fractionation studies, we observed, in the low glucose condition, an increase in the TG content available for lipoprotein assembly in the ER lumen, with the cytosolic/microsomal TG levels being verapamil-sensitive. Overall, we demonstrate that Caco-2 enterocytes modulate TRL secretion through TG partitioning between the cytosol and the ER lumen according to the glucose supply. Our model will help in identifying the proteins involved in the control of the balance between TRL assembly and cytosolic lipid storage. This mechanism may be a way for enterocytes to regulate TRL secretion after a meal, and thus impact on our understanding of post-prandial hypertriglyceridaemia.

Lipid-dependent bidirectional traffic of apolipoprotein B in polarized enterocytes

Enterocytes are highly polarized cells that transfer nutrients across the intestinal epithelium from the apical to the basolateral pole. Apolipoprotein B (apoB) is a secretory protein that plays a key role in the transepithelial transport of dietary fatty acids as triacylglycerol. The evaluation of the control of apoB traffic by lipids is therefore of particular interest. To get a dynamic insight into this process, we used the enterocytic Caco-2 cells cultured on microporous filters, a system in which the apical and basal compartments can be delimited. Combining biochemical and morphological approaches, our results showed that, besides their role in protection from degradation, lipids control the intracellular traffic of apoB in enterocytes. A supply of fatty acids and cholesterol is sufficient for the export of apoB from the endoplasmic reticulum and its post-Golgi traffic up to the apical brush-border domain, where it remains until an apical supply of complex lipid micelles signals its chase down to the basolateral secretory domain. This downward traffic of apoB involves a microtubule-dependent process. Our results demonstrate an enterocyte-specific bidirectional process for the lipid-dependent traffic of a secretory protein.

Lipid micelles stimulate the secretion of triglyceride-enriched apolipoprotein B48-containing lipoproteins by Caco-2 cells

Intestinal triglyceride-rich lipoproteins (TRL) are synthesized from dietary lipids. This study was designed to evaluate the effects of lipid micelles, mimicking post-digestive duodenal micelles, on the fate of apolipoprotein B (apoB)48-containing lipoproteins by Caco-2 cells. Such micelles, consisting of oleic acid (OA), taurocholate, 2-monooleoylglycerol (2-MO), cholesterol (Chol), and L-alpha-lysophospatidylcholine, were the most efficient inducers of OA uptake and esterification. The efficiency of TG and apoB48 secretion increased specifically as a function of cell differentiation. PAGE analysis of secreted lipoproteins separated by sequential ultracentrifugation after [35S] labeling revealed differences in the secretion of apoB100- and apoB48-containing lipoproteins. In absence of micelles, apoB48 was secreted mostly in "HDL-like" particles, as observed in enterocytes in vivo. Micelle application increased 2.7-fold the secretion of apoB, resulting in 53 times more apoB48 being recovered as TG-enriched lipoproteins at d < 1.006 g/ml. Electron microscopy revealed the presence of lipid droplets in the secretory pathway and the accumulation of newly synthesized TG in cytoplasmic lipid droplets, as in enterocytes in vivo. We showed that these droplets could be used for secretion. However, apoB48 preferentially bound to newly synthesized TG in the presence of micelles, accounting in part for the functional advantage of apoB editing in the intestine. While Caco-2 cells express both apoB isoforms, our results show that the apical supply of complex lipid micelles favors the physiological route of apoB48-containing TG-enriched lipoproteins.

The cellular prion protein PrPc is expressed in human enterocytes in cell-cell junctional domains

The physiological function of PrPc, the cellular isoform of prion protein, still remains unclear, although it has been established, in vitro or by using nerve cells, that it can homodimerize, bind copper, or interact with other proteins. Expression of PrPc was demonstrated as necessary for prion infection propagation. Considering the importance of the intestinal barrier in the process of oral prion infectivity, we have analyzed the expression of PrPc in enterocytes, which represent the major cell population of the intestinal epithelium. Our study, conducted both on normal human intestinal tissues and on the enterocytic cell line Caco-2/TC7, shows for the first time that PrPc is present in enterocytes. Interestingly, we found that this glycosylphosphatidylinositol-anchored glycoprotein was localized in cholesterol-dependent raft domains of the upper lateral membranes of enterocytes, beneath tight junctions, in cell-cell junctional domains. We observed that PrPc, E-cadherin, and Src co-localized in adherens junctions and that PrPc was co-immunoprecipitated with Src kinase but not with E-cadherin. Alteration of cell polarity after cholesterol depletion or loosening of the cell-cell junctions after EGTA treatment rapidly impaired membrane targeting of PrPc. Overall, our results point out the signaling of cell-cell contacts as a putative role for PrPc in epithelial cells.

HPV DNA detection by in situ hybridization with catalyzed signal amplification on thin-layer cervical smears

Thin layer-based technology in cervical cancer screening now allows both Papanicolaou staining and HPV testing on the same sample. Here, we show that in situ hybridization with catalyzed reporter deposition is a powerful HPV detection method when applied on thin-layer cervical smears, allowing distinction between two staining patterns suggestive of two different physical states of HPV DNA, where diffuse signals are suggestive of episomes and punctate signals are suggestive of viral DNA integration.

Membrane topology and mitochondrial targeting of mitofusins, ubiquitous mammalian homologs of the transmembrane GTPase Fzo

Two human Fzo-homologs, mitofusins Mfn1 and Mfn2, are shown by RT-PCR and western blot to be ubiquitous mitochondrial proteins. Protease digestion experiments reveal that Mfn2 is an outer membrane protein with N-terminal and C-terminal domains exposed towards the cytosol. The transmembrane and C-terminal domains of Mfn2 (Mfn2-TMCT) are targeted to mitochondria and deletion of these domains leads to the cytosolic localization of truncated Mfn2 (Mfn2-NT). Mfn2 is targeted to the endoplasmic reticulum or to mitochondria when the C-terminal domain is replaced by short stretches of neutral/hydrophobic (Mfn2-IYFFT) or polar/basic (Mfn2-RRD) amino acids. The coiled-coil domains of Mfn2, upstream and downstream of the transmembrane domain, are also important for mitochondrial targeting: Mfn2-mutants deleted of any of its coiled-coil domains are only partially targeted to mitochondria and significant protein amounts remain cytosolic. We show that these coiled-coil domains interact with each other: mistargeted Mfn2-NT or Mfn2-IYFFT localize to mitochondria if co-expressed with Mfn2-TMCT. This relocalization is abolished when the coiled-coil domain is deleted in any of the co-transfected molecules. We also found that Mfn2 can cluster active mitochondria in the perinuclear region independently of the cytoskeleton,bring mitochondrial membranes into close contact and modify mitochondrial structure, without disturbing the integrity of the inner and outer membrane.

Multi-minicore disease--searching for boundaries: phenotype analysis of 38 cases

Multi-minicore disease (MmD) is a congenital myopathy morphologically defined by the presence of multiple small zones of sarcomeric disorganization and lack of oxidative activity ("minicores") in muscle fibers. The dinical expression of MmD is considered to be greatly variable, and the morphological lesions are nonspecific; therefore, its boundaries are poorly defined, and its molecular bases are not known. To better define the phenotypic characteristics of MmD, we analyzed a large series of 38 patients with multiple minicores in muscle fibers in the absence of any other potential cause. According to clinical features, 4 subgroups were identified. Most patients (30 cases) shared a common highly consistent phenotype marked by the axial predominance of muscle weakness and a high occurrence of severe respiratory insufficiency and scoliosis ("classical" form). Other forms were characterized by pharyngolaryngeal involvement and total lack of head control (2 cases), antenatal onset with arthrogryposis (3 cases), and slowly progressive weakness with marked hand amyotrophy (3 cases). Type 1 fiber predominance and hypotrophy as well as centrally located nuclei were found in every subgroup. MmD is thus phenotypically heterogeneous, but a typical recognizable phenotype does exist. This phenotype classification should be helpful when undertaking research into the molecular defects that cause MmD.

Functional mitochondrial heterogeneity in heteroplasmic cells carrying the mitochondrial DNA mutation associated with the MELAS syndrome (mitochondrial encephalopathy, lactic acidosis, and strokelike episodes)

Most mitochondrial DNA (mtDNA) alterations associated with human disorders are heteroplasmic, i.e. mutant mtDNA molecules coexist with normal ones within the cell. We addressed the possibility of intermitochondrial exchanges through histologic analyses of cybrid clones with increasing proportion of the MELAS (A3243G) mtDNA transfer RNA point mutation. MtDNA-dependent cytochrome c oxidase activity and protein composition as well as mitochondrial membrane potential appeared heterogeneous in individual cells from clonal heteroplasmic cell populations on the basis of confocal and electron microscopy. The number of defective cells increased with increasing mutation load. We conclude that in the presence of a heteroplasmic mtDNA mutation in the cell type that we studied, intermitochondrial molecular exchanges cannot provide an efficient even distribution of the complementing molecules such as wild-type mtDNA, transfer RNA, or protein. Mitochondria in these heteroplasmic cells cannot, therefore, be considered a single functional unit.

[Familial myopathy with desmin storage seen as a granulo-filamentar, electron-dense material with mutation of the alphaB-cristallin gene]

Two familial cases of a myopathy remarkable by the presence of a granulo-filamentar, electron dense material were reported in 1978. In a second step, in 1988, it was demonstrated that this material contained an abnormally-phosphorylated desmin. During the last twenty years, the occurrence of new cases in this family confirmed the autosomal dominant inheritance of the disease, and made it potentially informative for molecular genetics studies. This allowed first to map the disease on chromosome11q21-23, and afterwards to identify a mutation within a gene coding for a chaperone protein, alphaBcrystallin. An extensive clinical, pathological and genetic study of this princeps family is herein reported in detail. First, it showed the possible detection of histopathological changes in presymptomatic patients. Second, it allowed to demonstrate the simultaneous occurrence of both alphaBcrystallin and desmin in the granulo-filamentar aggregates. Third, this study provided a precise knowledge of the evolution rate of the disease. The analysis of similar observations reported in the literature clearly shows the clinical, pathological and genetic heterogeneity of this new neuro-muscular disorder.

Exposure to print and word recognition processes

The effect of exposure to print on the efficiency of phonological and orthographic word recognition processes was examined by comparing two groups of university students having similar reading comprehension scores but different levels of exposure to print. Participants with a high level of exposure to print were faster and more accurate in naming pseudowords, in choosing the correct member of a homophone pair, and in making lexical decisions when nonwords were pseudohomophones. In the lexical decision task, low-print-exposure participants were more sensitive to the frequency of the orthographic patterns in the stimuli. The results of a form priming task demonstrated that high-print-exposure participants more quickly and strongly activated the orthographic representations of common words and subsequently more strongly activated the corresponding phonological representations. Even among successful students, differences in exposure to print produce large differences in the efficiency of both orthographic and phonological word recognition processes.

Adult onset reducing body myopathy

We report the case of a 28 year-old woman with left scapuloperoneal syndrome since the age of 24. The course was slowly progressive and diffuse weakness was observed 4 years later. Serum creatine kinase levels were moderately elevated (x3 normal value) and EMG showed mixed neurogenic and myogenic patterns. Muscle biopsy showed type I predominance and numerous reducing bodies in muscle fibers. Reducing bodies were strongly immunoreactive with antibodies to dystrophin, alpha-sarcoglycan, vimentin and ubiquitin. Desmin immunoreactivity was increased at the periphery of some reducing bodies but alphaB crystallin, alpha actinin, titin and nebulin were negative. Western blot analysis showed an increase in dystrophin, vimentin and desmin expression. Ultrastructurally, reducing bodies were composed of tubulofilamentous material, 17 nm in diameter, and immunoreactive with anti-Dys 2 antibody. Granulofilamentous material, immunoreactive with anti-desmin antibody was observed at the periphery of some reducing bodies. This report further highlights the proteinic composition of reducing bodies and shows that late onset reducing body myopathy may occur.

Prevention of autoimmune attack by targeting specific T-cell receptors in a severe combined immunodeficiency mouse model of myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease targeting the skeletal muscle acetylcholine receptor. We have previously demonstrated a selection bias of CD4+ T cells expressing the Vbeta5.1 T-cell receptor gene in the thymus of HLA-DR3 patients with MG. To evaluate the pathogenicity of these cells, severe combined immunodeficiency mice engrafted with MG thymic lymphocytes were treated with anti-Vbeta5.1 antibody. Signs of pathogenicity (eg, acetylcholine receptor loss and complement deposits at the muscle end plates of chimeric mice) were prevented in anti-Vbeta5.1-treated severe combined immunodeficiency chimeras. Pathogenicity was mediated by autoantibodies against acetylcholine receptor. Thymic cells depleted of Vbeta5.1-positive cells in vitro before cell transfer were nonpathogenic, indicating that Vbeta5.1-positive cells are involved in the production of pathogenic autoantibodies. Acetylcholine receptor loss was prevented by Vbeta5.1 targeting in HLA-DR3 patients only, demonstrating specificity for HLA-DR3-peptide complexes. The action of the anti-Vbeta5.1 antibody involved both the in vivo depletion of Vbeta5.1-expressing cells and an increase in the interferon-gamma/interleukin-4 ratio, pointing to an immune deviation-based mechanism. This demonstration that a selective and specific T-helper cell population is involved in controlling pathogenic autoantibodies in MG holds promise for the treatment of MG.

Mutation in the human acetylcholinesterase-associated collagen gene, COLQ, is responsible for congenital myasthenic syndrome with end-plate acetylcholinesterase deficiency (Type Ic)

Congenital myasthenic syndrome (CMS) with end-plate acetylcholinesterase (AChE) deficiency is a rare autosomal recessive disease, recently classified as CMS type Ic (CMS-Ic). It is characterized by onset in childhood, generalized weakness increased by exertion, refractoriness to anticholinesterase drugs, and morphological abnormalities of the neuromuscular junctions (NMJs). The collagen-tailed form of AChE, which is normally concentrated at NMJs, is composed of catalytic tetramers associated with a specific collagen, COLQ. In CMS-Ic patients, these collagen-tailed forms are often absent. We studied a large family comprising 11 siblings, 6 of whom are affected by a mild form of CMS-Ic. The muscles of the patients contained collagen-tailed AChE. We first excluded the ACHE gene (7q22) as potential culprit, by linkage analysis; then we mapped COLQ to chromosome 3p24.2. By analyzing 3p24.2 markers located close to the gene, we found that the six affected patients were homozygous for an interval of 14 cM between D3S1597 and D3S2338. We determined the COLQ coding sequence and found that the patients present a homozygous missense mutation, Y431S, in the conserved C-terminal domain of COLQ. This mutation is thought to disturb the attachment of collagen-tailed AChE to the NMJ, thus constituting the first genetic defect causing CMS-Ic.

Autosomal dominant late adult onset distal leg myopathy

A distal myopathy characterised by an autosomal dominant inheritance, with clinical onset around the age of 60, early involvement of posterior leg and thigh muscles, and normal or slightly-elevated creatine kinase levels was identified in three members of a French kindred. Tibialis anterior muscles were involved only in the most severely-affected sibling. Histological features included large multiple nonrimmed vacuolation and focal intrasarcoplasmic masses which immunoreacted with the anti-desmin antibody. Cytoplasmic and intranuclear tubulofilamentous inclusions were observed by electron microscopy. The condition of this familial syndrome is discussed in relation to previously-identified autosomal dominant distal myopathies and inclusion body myopathies.

A missense mutation in the alphaB-crystallin chaperone gene causes a desmin-related myopathy

Desmin-related myopathies (DRM) are inherited neuromuscular disorders characterized by adult onset and delayed accumulation of aggregates of desmin, a protein belonging to the type III intermediate filament family, in the sarcoplasma of skeletal and cardiac muscles. In this paper, we have mapped the locus for DRM in a large French pedigree to a 26-cM interval in chromosome 11q21-23. This region contains the alphaB-crystallin gene (CRYAB), a candidate gene encoding a 20-kD protein that is abundant in lens and is also present in a number of non-ocular tissues, including cardiac and skeletal muscle. AlphaB-crystallin is a member of the small heat shock protein (shsp) family and possesses molecular chaperone activity. We identified an R120G missense mutation in CRYAB that co-segregates with the disease phenotype in this family. Muscle cell lines transfected with the mutant CRYAB cDNA showed intracellular aggregates that contain both desmin and alphaB-crystallin as observed in muscle fibers from DRM patients. These results are the first to identify a defect in a molecular chaperone as a cause for an inherited human muscle disorder.

Autosomal recessive oculopharyngodistal myopathy in light of distal myopathy with rimmed vacuoles and oculopharyngeal muscular dystrophy

We investigated two Japanese siblings presenting with oculopharyngodistal myopathy, whose healthy parents were consanguineous. To clarify their disease characteristics, we compared them with four patients with distal myopathy with rimmed vacuoles linked to chromosome 9p1-q1, and 36 patients with oculopharyngeal muscular dystrophy linked to 14q11.2-q13. The first symptom in the patients with autosomal recessive oculopharyngodistal myopathy was weakness of the tibialis anterior muscle. Their biceps muscles showed initial and advanced myogenic changes, with rimmed vacuoles in 3% and 6% of the muscle fibers, respectively. In contrast, patients with distal myopathy with rimmed vacuoles revealed many rimmed vacuoles, on average in 20% of the fibers, and their oculopharyngeal muscles were spared. None of the patients with oculopharyngeal muscular dystrophy showed distal dominant weakness and the occurrence of rimmed vacuoles was rare. Ultrastructural studies in groups of autosomal recessive oculopharyngodistal myopathy and distal myopathy with rimmed vacuoles disclosed a collection of cytoplasmic filaments of 16-18 nm, but oculopharyngeal muscular dystrophy-specific intranuclear inclusions of 8.5 nm were not found. Thus, the phenotype of autosomal recessive oculopharyngodistal myopathy is distinct from distal myopathy with rimmed vacuoles and oculopharyngeal muscular dystrophy, but shares some ultrastructural characteristics with distal myopathy with rimmed vacuoles and hereditary inclusion body myopathy.

Morphological changes in muscle fibers in oculopharyngeal muscular dystrophy

The study of muscle biopsies of 29 cases of oculopharyngeal muscular dystrophy (OPMD) showed the two main morphological features of this disease: rimmed vacuoles (in 26 cases) and intranuclear inclusions (in all cases). These inclusions are made of 8.5 nm tubular filaments and the areas occupied by them are lighter than the surrounded nucleoplasm. This can be seen by light microscopy, facilitating the detection of the tubulo-filamentous inclusions which can only be identified with certitude by electron microscopy. In a given ultrathin section the area occupied by these inclusions varied from 2% to 5% of the nuclei. The intranuclear inclusions are the morphological marker of OPMD and their finding in a muscle biopsy allows the exact diagnosis of this disease. The origin and biochemical nature of the intranuclear inclusions is unknown.

Oculopharyngeal muscular dystrophy in Japan

Oculopharyngeal muscular dystrophy (OPMD) in the European population has been frequently diagnosed, but except for one black family, the occurrence in other ethnic groups is uncertain. We identified two unrelated OPMD Japanese families, including 34 affected individuals. Major clinical manifestations were bilateral ptosis and dysphagia starting after age 40. Histologic studies of limb muscles revealed mild myogenic changes, occasional rimmed vacuoles, and small angulated fibers. By contrast, cricopharyngeal muscle showed a marked loss of fibers and massive proliferation of connective tissue. Intranuclear tubulofilamentous inclusions (ITFI) of 8.5 nm outer diameter were observed in 2-5% of the nuclei in four different biopsied muscles. One patient with recurrent aspirations underwent successful cricopharyngeal myotomy. Aerodynamic examination was useful to evaluate velopharyngeal closure function. Our investigations revealed that OPMD is a geographically widespread disorder, and ITFI may be the specific morphologic hallmark.

Retinoid receptors in rat vaginal and uterine epithelia: changes with ovarian steroids

In rats, vaginal epithelium shows cyclic changes with an alternating pattern of keratinization under estrogen control and mucification under progesterone control. Since retinoids suppress keratinizing differentiation, in this paper we studied the expression of the major retinoid receptors normally present in keratinizing squamous epithelia: RAR alpha, RAR gamma and RXR alpha. In cyclic rats and steroid-treated ovariectomized rats, RXR alpha and RAR gamma were detected in basal and suprabasal cells while RAR alpha was mainly localized in suprabasal cells. No changes in RAR gamma expression were observed in correlation with ovarian steroids. During diestrus and in ovariectomized rats, the superficial cuboid cells expressed the three receptors. In the uterine epithelium, RAR alpha, RAR gamma and RXR alpha expression was induced by estrogens. Retinoic acid treatment did not modify retinoid receptor expression in vaginal and uterine epithelia. These data suggest specific roles for the different receptors in the complex process of vaginal epithelium proliferation and differentiation under estrogens and retinoic acid control.

[Exercise intolerance caused by muscular phosphorylase kinase deficiency. Contribution of in vivo metabolic studies]

A 33 year old man has been presenting since childhood an exertional muscle pain syndrome without myoglobinuria. Muscle biopsy revealed a vacuolar myopathy with glycogen excess in subsarcolemmal and intermyofibrillar spaces which was confirmed by electron microscopy. Plasma production of ammonia was abnormally high during exercise on a bicycle ergometer while the raise of lactate was normal. NMR spectroscopy showed an increased muscle glycogen content, with a slight and delayed drop of the pH during exercise. Phosphorylase b kinase activity was undetectable in muscle specimen whereas activities of others enzymes of carbohydrate metabolism were normal. Clinical presentation of our patient is compared to that of the reported cases of phosphorylase b kinase deficiency.

Regulation of differentiation and keratin 10 expression by all-trans retinoic acid during the estrous cycle in the rat vaginal epithelium

In rodents, the vaginal epithelium shows cyclic changes with an alternating pattern of keratinization under estrogen control and mucification under progesterone control. Retinoids are powerful regulators of cell differentiation, an excess of retinoids suppressing the keratinizing differentiation of keratinocytes. Here, we have examined the vaginal epithelium during the estrous cycle and compare the effects of retinoids on both types of hormonally induced differentiation, i.e. keratinization and mucification. All-trans retinoic acid was administered either by daily injections during the estrous cycle or by a single injection before the estrogen rise; these two protocols gave similar results. Retinoic acid suppressed estrogen-induced vaginal keratinization and cytokeratin K10 expression (a biochemical marker of terminal differentiation). Progesterone-induced mucification was not impaired; however, retinoic acid impeded mucous cell desquamation, suggesting an effect of retinoic acid on cell adhesiveness. Retinoic acid induced the appearance of apoptotic-like cells, as revealed by immunocytochemical staining of DNA fragmentation.

Oculopharyngeal muscular dystrophy in two unrelated Japanese families

The occurrence of oculopharyngeal muscular dystrophy (OPMD) in Orientals is uncertain. We identified two unrelated Japanese families, including 30 affected individuals (14 men, 16 women, mean age 58 years) of OPMD through four generations, with complete penetrance. Their major clinical manifestations were late-onset bilateral ptosis and dysphagia. Histologic studies of slightly affected muscles reveal mild myogenic changes, occasional rimmed vacuoles, and small angulated fibers. By contrast, the severely involved cricopharyngeal muscle showed marked loss of fibers and massive proliferation of connective tissue. Ultrastructural studies of four different biopsied muscles disclosed subsarcolemmal intranuclear tubulofilamentous inclusions, identical to those of non-Japanese OPMD patients.

Vaginal keratinization during the estrous cycle in rats: a model for evaluating retinoid activity

A model is described for evaluating the activity of a retinoid based on its effect on the keratinization of the vaginal epithelium that occurs on estrus (day 4) of a 4-day cycle in female rats. This keratinization process is dependent on the endogenous estradiol (E2) secreted between the evening of diestrus 2 (day 2) and that of proestrus (day 3). Various doses of all-transretinoic acid (tRA) were injected at different time points during the estrous cycle and the vaginal keratinization was assessed by microscope examination of unstained native or Papanicolaou-stained smear preparations. Additionally, the preovulatory E2 secretion was measured and ovaries were histologically examined. A single injection of 10 mg/kg tRA either on diestrus 2 (evening) or on proestrus (early morning) was able to induce a complete inhibition of the vaginal keratinization in more than 80% of the cases. This can be considered as a direct effect on the vaginal epithelial differentiation since neither the E2 secretion nor the ovulatory process were affected. The inhibition of vaginal keratinization can be used as a rapid and convenient in vivo model for screening retinoid candidates with antikeratinizing activity.