IgG antiendothelial cell autoantibodies from scleroderma patients induce leukocyte adhesion to human vascular endothelial cells in vitro. Induction of adhesion molecule expression and involvement of endothelium-derived cytokines

IgG autoantibodies that bind human endothelial cells (AECA) were detected by ELISA in 30 of 42 samples of sera from patients with scleroderma. Pretreatment of human umbilical vein endothelial cells with AECA-positive scleroderma sera, or IgG purified from these sera, led to a dose- and time-dependent increase in the ability of the cells to bind human U937 monocytic cells. Threshold-active IgG concentrations were 1-10 micrograms/ml; effects were significant after 3 h and maximal after 6-12 h. IgG from AECA-negative sera or normal sera were without effect. Increased adhesion of U937 cells was accompanied by increased expression of endothelial intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin. Transfer of endothelial cell-conditioned media after pretreatment with AECA and immunodepletion of IgG demonstrated the presence of transferable activity that mimicked the effects of AECA. Treatment with neutralizing anticytokine antibodies indicated that IL-1, generated by the endothelial cells in response to AECA, was involved in the upregulation of adhesion molecules and U937 cell adhesion. We conclude that AECA can play a pathogenic role in scleroderma by activating endothelial cells, in part due to autocrine or paracrine actions of IL-1.

Complete genome sequence of the sugarcane nitrogen-fixing endophyte Gluconacetobacter diazotrophicus Pal5

BACKGROUND

Gluconacetobacter diazotrophicus Pal5 is an endophytic diazotrophic bacterium that lives in association with sugarcane plants. It has important biotechnological features such as nitrogen fixation, plant growth promotion, sugar metabolism pathways, secretion of organic acids, synthesis of auxin and the occurrence of bacteriocins.

RESULTS

Gluconacetobacter diazotrophicus Pal5 is the third diazotrophic endophytic bacterium to be completely sequenced. Its genome is composed of a 3.9 Mb chromosome and 2 plasmids of 16.6 and 38.8 kb, respectively. We annotated 3,938 coding sequences which reveal several characteristics related to the endophytic lifestyle such as nitrogen fixation, plant growth promotion, sugar metabolism, transport systems, synthesis of auxin and the occurrence of bacteriocins. Genomic analysis identified a core component of 894 genes shared with phylogenetically related bacteria. Gene clusters for gum-like polysaccharide biosynthesis, tad pilus, quorum sensing, for modulation of plant growth by indole acetic acid and mechanisms involved in tolerance to acidic conditions were identified and may be related to the sugarcane endophytic and plant-growth promoting traits of G. diazotrophicus. An accessory component of at least 851 genes distributed in genome islands was identified, and was most likely acquired by horizontal gene transfer. This portion of the genome has likely contributed to adaptation to the plant habitat.

CONCLUSION

The genome data offer an important resource of information that can be used to manipulate plant/bacterium interactions with the aim of improving sugarcane crop production and other biotechnological applications.

IgG anti-endothelial cell autoantibodies from patients with systemic lupus erythematosus or systemic vasculitis stimulate the release of two endothelial cell-derived mediators, which enhance adhesion molecule expression and leukocyte adhesion in an autocrine manner

OBJECTIVE

To investigate the ability of anti-endothelial cell antibodies (AECA) to modulate endothelial cell function.

METHODS

The effects of purified IgG from 11 patients with systemic lupus erythematosus (SLE) and 4 patients with systemic vasculitis on the expression of adhesion molecules (intercellular adhesion molecule 1, vascular cell adhesion molecule 1, E-selectin) by human umbilical vein endothelial cells and on the adhesion of the human promyelocytic cell line U937 were examined in vitro.

RESULTS

IgG from 6 of 8 AECA-positive SLE patients and 3 of 3 AECA-positive systemic vasculitis patients up-regulated adhesion molecule expression and leukocyte adhesion to endothelial cells. The 4 AECA-negative samples had no effect. Transfer experiments demonstrated that at later time points (2-8 hours) after AECA addition, endothelium-derived interleukin-1 (IL-1) accounted for the ability of AECA to increase leukocyte adhesion. However, even within very short times after addition of AECA (<30 minutes), endothelial cells released a distinct transferable mediator with similar effects.

CONCLUSION

AECA in patients with SLE or systemic vasculitis may contribute to pathogenesis by increasing leukocyte adhesion to endothelial cells. AECA act by inducing the release of at least two endothelium-derived mediators, one (as-yet-unidentified) rapidly and another (IL-1) more slowly, both of which stimulate endothelial cells in an autocrine manner.

A compendium answering 150 questions on COVID-19 and SARS-CoV-2

In December 2019, China reported the first cases of the coronavirus disease 2019 (COVID-19). This disease, caused by the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2), has developed into a pandemic. To date, it has resulted in ~9 million confirmed cases and caused almost 500 000 related deaths worldwide. Unequivocally, the COVID-19 pandemic is the gravest health and socioeconomic crisis of our time. In this context, numerous questions have emerged in demand of basic scientific information and evidence-based medical advice on SARS-CoV-2 and COVID-19. Although the majority of the patients show a very mild, self-limiting viral respiratory disease, many clinical manifestations in severe patients are unique to COVID-19, such as severe lymphopenia and eosinopenia, extensive pneumonia, a "cytokine storm" leading to acute respiratory distress syndrome, endothelitis, thromboembolic complications, and multiorgan failure. The epidemiologic features of COVID-19 are distinctive and have changed throughout the pandemic. Vaccine and drug development studies and clinical trials are rapidly growing at an unprecedented speed. However, basic and clinical research on COVID-19-related topics should be based on more coordinated high-quality studies. This paper answers pressing questions, formulated by young clinicians and scientists, on SARS-CoV-2, COVID-19, and allergy, focusing on the following topics: virology, immunology, diagnosis, management of patients with allergic disease and asthma, treatment, clinical trials, drug discovery, vaccine development, and epidemiology. A total of 150 questions were answered by experts in the field providing a comprehensive and practical overview of COVID-19 and allergic disease.

Inhibition of thyroid type 1 deiodinase activity by flavonoids

Some dietary flavonoids inhibit thyroperoxidase and hepatic deiodinase activity, indicating that these compounds could be classified as anti-thyroid agents. In this study, we evaluated the in vitro effect of various flavonoids on thyroid type 1 iodothyronine deiodinase activity (D1). D1 activity was measured in murine thyroid microsome fractions by the release of 125I from 125I-reverse T3. D1 activity was significantly inhibited by all the flavonoids tested; however, the inhibitory potencies on thyroid D1 activity differed greatly among them. A 50% inhibition of D1 activity (IC(50)) was obtained at 11 microM baicalein, 13 microM quercetin, 17 microM catechin, 55 microM morin, 68 microM rutin, 70 microM fisetin, 72 microM kaempferol and 77 microM biochanin A. Our data reinforce the concept that dietary flavonoids might behave as antithyroid agents, and possibly their chronic consumption could alter thyroid function.

Role of estrogen on skeletal muscle mitochondrial function in ovariectomized rats: a time course study in different fiber types

Postmenopausal women are prone to develop obesity and insulin resistance, which might be related to skeletal muscle mitochondrial dysfunction. In a rat model of ovariectomy (OVX), skeletal muscle mitochondrial function was examined at short- and long-term periods after castration. Mitochondrial parameters in the soleus and white gastrocnemius muscle fibers were analyzed. Three weeks after surgery, there were no differences in coupled mitochondrial respiration (ATP synthesis) with pyruvate, malate, and succinate; proton leak respiration; or mitochondrial reactive oxygen species production. However, after 3 wk of OVX, the soleus and white gastrocnemius muscles of the OVX animals showed a lower use of palmitoyl-carnitine and glycerol-phosphate substrates, respectively, and decreased peroxisome proliferator-activated receptor-γ coactivator-1α expression. Estrogen replacement reverted all of these phenotypes. Eight weeks after OVX, ATP synthesis was lower in the soleus and white gastrocnemius muscles of the OVX animals than in the sham-operated and estrogen-treated animals; however, when normalized by citrate synthase activity, these differences disappeared, indicating a lower muscle mitochondria content. No differences were observed in the proton leak parameter. Mitochondrial alterations did not impair the treadmill exercise capacity of the OVX animals. However, blood lactate levels in the OVX animals were higher after the physical test, indicating a compensatory extramitochondrial ATP synthesis system, but this phenotype was reverted by estrogen replacement. These results suggest early mitochondrial dysfunction related to lipid substrate use, which could be associated with the development of the overweight phenotype of ovariectomized animals.

Retinoic acid in patients with radioiodine non-responsive thyroid carcinoma

De-differentiated thyroid carcinoma is characterized by loss of thyroid-specific functions and properties. The therapeutic options for this type of thyroid cancer are limited and generally not efficient. Recent studies with retinoic acid (RA) have shown that this drug can induce re-differentiation of the thyrocyte and tumor regression after 131I therapy. The aim of the present study was to assess the effects of RA therapy in patients with extensive thyroid tumor involvement, which lost radioiodine uptake ability. A total of 5 patients (1 follicular carcinoma, 3 papillary carcinomas and 1 poorly differentiated carcinoma) were treated with isotretinoin (1.0 to 1.5 mg/kg/day) for 5 weeks and then submitted to radioiodine therapy. Three parameters for assessment of RA effects were established: a) reduction of serum thyroglobulin levels; b) increment of the post-therapeutic dose radioiodine uptake; c) tumor size regression after therapy. All patients completed the treatment and the most frequent side effects were dry skin and lips and hypertriglyceridemia. One patient showed satisfactory response (2 or more of the 3 criteria were reached) and a new cycle of RA was given. In two, just a partial response (1 criterion) was seen and the other patients did not respond. Based on these results, isotretinoin might be an option for de-differentiated thyroid cancer, with low rate of severe side effects, especially when compared with cytotoxic drugs. Aggressive thyroid cancer frequently needs multimodal adjuvant therapy.

Determination of lamotrigine simultaneously with carbamazepine, carbamazepine epoxide, phenytoin, phenobarbital, and primidone in human plasma by SPME-GC-TSD

A simple and rapid analytical method is presented for the determination of lamotrigine simultaneously with primidone, carbamazepine, carbamazepine epoxide, phenobarbital, and phenytoin in human plasma using solid-phase microextraction (SPME) and gas chromatography with thermionic specific detection. The best conditions for the SPME procedure is established as following: direct extraction on a 65-microm Carbowax-divinylbenzene fiber; 1.0 mL of a sample plasma matrix modified with 15% NaCl and 3 mL of a potassium phosphate buffer (pH 7.0); extraction temperature at 30 degrees C; and stirring at a rate of 2500 rpm for 15 min. The method shows good linearity between 0.05 and 40.0 microg/mL with regression coefficients ranging between 0.9965 and 0.9995 and a coefficient of variation of the points of the calibration curve lower than 10%. The lowest limit of quantitation for the plasma-investigated drugs varies from 0.05 to 0.20 microg/mL, according to the drug. The proposed method is sensitive enough to work into subtherapeutic and therapeutic concentrations, being that it is applied in pharmacokinetic studies and patient routine therapeutic drug monitoring.

High-fat diet increases thyrotropin and oxygen consumption without altering circulating 3,5,3'-triiodothyronine (T3) and thyroxine in rats: the role of iodothyronine deiodinases, reverse T3 production, and whole-body fat oxidation

This study investigated the effects of obesity induced by high-fat (HF) diet on thyroid function and whole-body energy balance. To accomplish that, we assessed the effects of 8 wk of HF diet on several parameters of hypothalamus-pituitary-thyroid axis function. Serum total T(4) and T(3), rT(3), and TSH, the activity of type 1 and type 2 deiodinases in central and peripheral tissues were determined. Also, we measured in vivo energy balance, substrate partitioning, and markers of leptin resistance. Here we provide novel evidence that prolonged positive energy balance acquired by feeding a HF diet induced hyperactivation of the hypothalamus-pituitary-thyroid axis, which was characterized by 2.24-, 1.6-, and 3.7-fold elevations in hypothalamic TRH expression, thyroid iodide uptake, and serum TSH, respectively. Serum T(4) and T(3) were normal together with augmented deiodinase type 1 activity in liver (1.3-fold) and kidney (1.2-fold) and increased (1.5-fold) serum rT3 in HF rats. Despite no increase in circulating levels of T(3) and T(4), whole-body oxygen consumption was increased, and substrate metabolism was shifted toward fat oxidation in HF rats. These in vivo metabolic adjustments were mainly driven by the fat content of the diet. Furthermore, spontaneous dark cycle physical activity was reduced by 30% in rats fed a HF diet, which limited energy expenditure and favored the development of obesity. Our findings provide new insight into the endocrine and physiological mechanisms that underlie the alterations in thyroid hormone availability, energy balance, and metabolic partitioning in HF diet-induced obesity.

Biochemical characterization of a Ca2+/NAD(P)H-dependent H2O2 generator in human thyroid tissue

An NAD(P)H-dependent H2O2 forming activity has been evidenced in thyroid tissue from patients with Grave's disease. Its biochemical properties were compared to those of the NADPH oxidase previously described in pig thyroid gland. Both were Ca2+-dependent and activated by inorganic phosphate anions in the same range of concentrations. Both are flavoproteins using FAD as cofactor, but the human enzyme was also able to utilize FMN. The apparent Km for NADPH of the human enzyme (100 microM) was 5-10 times higher than that of porcine enzyme. Vm was 3 to 10 times higher in pig (150 nmol x h(-1) x mg(-1)) than in man (14 to 45). Total content in human tissue was 7 to 9% of that in porcine tissue. An unidentified inhibitor has been detected in the 3000 g particulate fraction from most patients, which could account for this apparently low enzyme content. An NADH-dependent H2O2 production has also been observed in porcine and human thyroid tissues. This activity was only partly Ca2+-dependent (man, 50-70%; pig, 80-90%) and presented similar apparent Km values for NADH (man, 100 microM; pig, 200 microM). In pig thyrocytes, the expression of the Ca2+-dependent part of the NADH-oxidase activity was induced by TSH and down-regulated by TGFbeta, as was the NADPH oxidase activity. Furthermore, NADPH and NADH-dependent activities were not additive. We conclude that a single, inducible, NAD(P)H-oxidase can use NADPH or NADH as substrate to catalyse H2O2 formation, and that human and porcine NAD(P)H-oxidases are highly similar. Differences observed could be attributed to minor differences in enzyme structure and/or in membrane microenvironment. The NADH-dependent Ca2+-independent activity observed in human and porcine thyroid fractions could be attributed to a distinct and constitutive enzyme.

Thickening of the pituitary stalk: a finding suggestive of intrasellar tuberculoma? Case report

We describe the case of a patient with an exclusively intrasellar mass, disclosed because of a left sixth nerve palsy and headaches. No other manifestation of disease, namely, endocrinological, was present. The lesion was approached transsphenoidally, and the pathological examination revealed a tuberculoma. Complete removal was achieved, and the patient started postoperative antituberculous therapy. In some circumstances, thickening of the infundibulum and the pituitary stalk could preoperatively suggest the diagnosis of hypophysial tuberculoma.

An atypical presentation of Kawasaki disease resembling a retropharyngeal abscess

Kawasaki disease is an acute systemic inflammatory disease, which occurs in children less than 10 years of age. The etiology of the disorder is unknown. Diagnosis is based upon clinician's recognition of a symptom pattern that includes high fevers, oral cavity changes, polymorphous rash, conjunctival injection, and cervical adenopathy. Most feared are the cardiac manifestations of Kawasaki syndrome, which result in an overall mortality rate of 2% in patients. Because of the common presenting symptoms, the otolaryngologist often plays a central role in early diagnosis of the disorder. The following case report describes a patient with Kawasaki disease whose initial presentation mimicked a retropharyngeal abscess. A literature review details the common and atypical early signs and symptoms of Kawasaki disease.

Ca(2+)/nicotinamide adenine dinucleotide phosphate-dependent H(2)O(2) generation is inhibited by iodide in human thyroids

A calcium and NAD(P)H-dependent H(2)O(2)-generating activity has been studied in paranodular thyroid tissues from four patients with cold thyroid nodules and from nine diffuse toxic goiters. H(2)O(2) generation was detected both in the particulate (P 3,000 g) and in the microsomal (P 100,000 g) fractions of paranodular tissue surrounding cold thyroid nodules (PN), with the same biochemical properties described for NADPH oxidase found in porcine and human thyroids. In PN tissues, the particulate NADPH oxidase activity (224 +/- 38 nmol H(2)O(2) x h(-1) x mg(-1) protein) was similar to that described for the porcine thyroid enzyme. However, no NADPH oxidase activity was detectable in the particulate fractions from eight diffuse toxic goiter patients treated with iodine before surgery; all but one also received propylthiouracil or methimazole in the preoperative period. Thyroid cytochrome c reductase (diffuse toxic goiters = 438 +/- 104 nmol NADP(+) x h(-1) x mg(-1) protein; PN = 78 +/- 10 nmol NADP(+) x h(-1) x mg(-1) protein) and thyroperoxidase (diffuse toxic goiters = 621 +/- 179 U x g(-1) protein; PN = 232 +/- 121 U x g(-1) protein) activities were unaffected by iodide. Thus, the human NADPH oxidase seems to be inhibited by iodinated compounds in vivo and probably is an enzyme involved in the Wolff-Chaikoff effect. Our findings reinforce the hypothesis that thyroid NADPH oxidase is responsible for the production of H(2)O(2) necessary for thyroid hormone biosynthesis.

Neonatal dermoid cyst of the floor of the mouth extending to the midline neck

We describe a male neonate who presented at birth with a compressible dermoid cyst that extended from the floor of the mouth to the midline of the neck. Ultrasonography revealed a fluid-filled sublingual mass. Magnetic resonance imaging performed when the patient was 1 week old demonstrated a 2-cm, cystic, left-sided, sublingual mass that crossed the midline without extension inferior to the mylohyoid muscle. At 3 months of age, the patient developed a 1-cm, solid, submental mass. At the time of surgery, the lesion had a fibromembranous tract that extended through the myolohyoid muscle to a 1-cm cyst in the submental region. Histologic sections depicted 2 dermoid cysts and a connecting fistula. This case represents the first report (to our knowledge) of a dermoid cyst presenting in a neonate as a mass in the floor of the mouth with extension to the midline of the neck.

Tissue-specific deiodinase regulation during food restriction and low replacement dose of leptin in rats

The relationship between thyroid function and leptin has been extensively studied; however, the mechanisms underlying the changes in thyroid hormone economy that occur during caloric deprivation remain elusive. Our goal was to evaluate the thyroid function of rats submitted to 40% food restriction after chronic leptin replacement. Caloric restriction for 25 days led to significantly reduced serum leptin, thyroid-stimulating hormone (TSH), thyroxine (T(4)), and triiodothyronine (T(3)) and increased serum corticosterone, while liver, kidney, and thyroid type I deiodinase (D1) and brown adipose tissue (BAT) type II deiodinase (D2) activities were decreased and hypothalamic D2 was significantly increased. Interestingly, thyroid iodide uptake was unchanged by caloric restriction, but thyroperoxidase (TPO) activity was significantly reduced. Leptin replacement for the last 10 days of caloric restriction normalized serum leptin and TSH levels, but serum T(4) and T(3) levels and thyroid D1 and TPO activities were not reestablished. Also, a negative effect of leptin administration on Na(+)-I(-) symporter function was detected. Liver and kidney D1 and hypothalamic and BAT D2 were normalized by leptin, while pituitary D2 was significantly decreased. In conclusion, a tissue-specific modulation of deiodinases might be implicated in the normalization of thyroid function during leptin replacement in food-restricted rats. Although leptin restores the hypothalamus-pituitary axis during food restriction, it exerts a direct negative effect on the thyroid gland; thus normalization of serum thyroid hormones might depend on changes in deiodinase activities and the long-term thyroid stimulation by TSH to counterbalance the direct negative effects of leptin on the thyroid gland.

Equal Access to Telemedicine during COVID-19 Pandemic: A Pediatric Otolaryngology Perspective

Objectives/Hypothesis

During the current COVID‐19 pandemic, the demand for direct‐to‐home telemedicine services has risen to an unprecedented level. Equal access to specialty care was assessed to identify potential barriers that may negatively impact telemedicine utilization.

Study design

Retrospective case series.

Methods

We examined the 6‐week period between March and May 2020 when the only access to nonurgent pediatric otolaryngology service was through telemedicine and compared it to in‐person visits during the same period in 2019. We compared patient demographics, including age, gender, preferred language, zip code of residence, and primary insurance plan.

Results

A total of 1,495 visits were conducted through telemedicine from March 23, 2020 to May 1, 2020, and 1983 in‐person visits were completed in 2019. There was no difference in patient age and gender. The proportions of Spanish‐speaking families were similar (15.8% in 2019 vs. 14.4% in 2020, P = .96). The percentage of Medi‐Cal‐insured patients (51.4% in 2019 vs. 49.8% in 2020, P = .73) and the mean poverty level (12.6% in 2019 vs. 12.2% in 2020, P = .38) also remained the same. Spanish‐speaking families were statistically more likely to require rescheduling of their telemedicine visits (17.2%) when compared to the overall rescheduling rate of 11.9% (P = .0083).

Conclusions

We were able to successfully provide access to telemedicine services to our vulnerable populations during the current COVID‐19 pandemic. Telemedicine is likely to remain an essential mode of delivering patient care going forward. It is important to evaluate and identify potential disparities to telemedicine access and proactively implement changes to address these barriers.

Level of Evidence

4. Laryngoscope, 131:1175–1179, 2021

Management of Large-Volume Subperiosteal Abscesses of the Orbit: Medical vs Surgical Outcomes

Objectives To compare clinical variables and outcomes for children with subperiosteal abscesses of the orbit (SPAO) managed medically vs surgically to identify clinical prognosticators. Study Design Case series with chart review. Setting Tertiary children's academic institution. Subjects and Methods The study included 48 children between the age of 1 month and 14 years, with SPAO from 2003 to 2013. Variables included age, sex, physical examination findings, laboratory results, computed tomography (CT) findings, hospital length of stay, length of antibiotic therapy, and placement of a peripherally inserted central catheter (PICC). Intended methods for comparison were the Student t test for continuous variables and Fisher's exact test for categorical variables, and a forward stepwise multiple logistic regression. Results Thirty-two (67%) children were successfully treated with antibiotic therapy only, and 16 (33%) required surgery. Abscess volume, abscess width, and the presence of gaze restriction were statistically different between the 2 groups. A multivariate analysis found abscess volume as the only predictor for surgical intervention. A subgroup analysis including only patients with an abscess volume of ≥500 mm³ (n = 26) was performed. Eleven patients were treated medically and 15 treated surgically, with the medical group having longer hospital stays ( P = .048), duration of antibiotic therapy ( P = .035), and higher incidence of PICC placement ( P = .005). Conclusions This is the first study to report that abscess volume has clinical implications, as children with SPAO volume ≥500 mm³ treated medically have longer inpatient admissions, antibiotic therapy durations, and PICC placement. When children present with an abscess ≥500 mm³, early surgical intervention should be strongly considered, even in the absence of other surgical criteria, to shorten duration of hospitalization and accelerate clinical improvement.

Solubilization and characterization of a thyroid Ca(2+)-dependent and NADPH-dependent K3Fe(CN)6 reductase. Relationship with the NADPH-dependent H2O2-generating system

The thyroid plasma membrane contains a Ca(2+)-regulated NADPH-dependent H2O2-generating system which provides H2O2 for the thyroid-peroxidase-catalyzed biosynthesis of thyroid hormones. The molecular nature of the membrane-associated electron transport chain that generates H2O2 in the thyroid is unknown, but recent observations indicate that a flavoprotein containing a FAD prosthetic group is involved. Solubilization was reinvestigated using 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (Chaps), Triton X-100, and high salt concentrations. Chaps eliminated about 30% of the proteins, which included a ferricyanide reductase, without affecting the H2O2-generating system. Similarly, Triton X-100 alone did not extract the NADPH oxidase. An NADPH-oxidase activity, which was measured in the presence of the artificial electron acceptor potassium ferricyanide, was solubilized by increasing the ionic strength to 2 M KCl. This NADPH-ferricyanide reductase activity was shown to belong to the H2O2-generating system, although it did not produce H2O2. It was still Ca2+ dependent and H2O2 production was restored by decreasing the ionic strength by overnight dialysis. No H2O2 production activity was detected after sucrose density gradient centrifugation of the dialyzed solubilized enzyme, but a well-defined peak of NADPH oxidation activity with a sedimentation coefficient of 3.71 S was found in the presence of K3Fe(CN)6. These results suggest that some unknown component(s) (phospholipid or protein) is removed during sucrose density gradient centrifugation. Finally, thyrotropin, which induces NADPH oxidase and regulates H2O2 production in porcine thyrocytes in primary culture, also induced the NADPH-K3Fe(CN)6 reductase activity associated with the H2O2-generating system. Thus, this enzyme seems to be another marker of thyroid differentiation.

The Ca2+- and reduced nicotinamide adenine dinucleotide phosphate-dependent hydrogen peroxide generating system is induced by thyrotropin in porcine thyroid cells

Hydrogen peroxide (H2O2) is an essential electron acceptor for thyroid peroxidase-catalyzed iodination and coupling reactions. In the presence of iodide, its production is a limiting step in thyroid hormone biosynthesis. Several studies have demonstrated that the thyroid particulate fraction contains a Ca2+- and NADPH- dependent H@O@ generator (NADPH-O2:oxidoreductase), the so- called thyroid NADPH-oxidase. It has recently been demonstrated that cellular H2O2 release is under the tonic control of TSH in primary cultures of dog thyrocytes. The present study evaluates the effect of TSH on the thyroid NADPH-oxidase and cytochrome c reductase activities, two enzymes believed to be involved on H2O2 generation in the thyroid gland. There was almost no detectable NADPH-dependent H2O2 generator in the membranes of cells grown for 18 h without TSH. But cells grown in the presence of TSH (0.1 mU/ml) had a CA2+- and NADPH-dependent H2O2-generating activity that increased up to the third day in culture, as did the cell iodide organification capacity. This increase was also partially blocked by 12-O-tetradecanoylphorbol 13-acetate and cycloheximide. Forskolin and 8-bromo-cAMP both reproduced the action of TSH on the Ca2+- and NADPH-dependent H2O2 generator. In contrast, the thyroid NADPH-cytochrome c reductase activity in particles from control cells was similar to that of TSH-treated cells and was unaffected by forskolin or 12-O-tetradecanoylphorbol 13-acetate. These results suggest that NADPH-cytochrome c reductase activity is not regulated by TSH and, thus, reinforce the idea that this enzyme is not involved in thyroid H2O2 generation. On the other hand, the Ca2+- and NADPH-dependent H2O2 generator, so-called thyroid NADPH- oxidase, is induced by TSH through the cAMP cascade. Thus, it seems to be another marker of thyroid differentiation, in addition to thyroperoxidase and thyroglobulin, and could play a key role in thyroid hormone production.

Determination of amitraz in canine plasma by solid-phase microextraction-gas chromatography with thermionic specific detection

A simple and rapid analytical method is presented for the determination of amitraz in canine plasma samples using solid-phase microextraction (SPME) and gas chromatography with thermionic specific detection (GC-TSD). The best conditions for the SPME procedure were: direct extraction on a polydimethlysiloxane (PDMS) fiber with 100-microm film thickness; 400 &microl of sample plasma matrix modified with 4 ml sodium borate solution (0.01 mol l(-1), pH 6.5); extraction temperature 70 degrees C, with stirring at 2500 rpm for 45 min. The method was linear between 20 and 400 ng ml(-1) with regression coefficients corresponding to 0.998 and coefficient of the variation of the points of the calibration curve lower than 15%. The lowest limit of quantification (LOQ) for amitraz in plasma was 20 ng ml(-1). This LOQ was determined as the lowest concentration on the calibration curve in which the coefficient of variation was lower than 15%. The proposed method was applied to determine amitraz concentrations in canine plasma to look for toxicity after treatment with amitraz in a dipping bath.

Estradiol modulates TGF-β1 expression and its signaling pathway in thyroid stromal cells

The higher prevalence of thyroid disease in women suggests that estrogen (E2) might be involved in the pathophysiology of thyroid dysfunction. To approach the question of the effect of stromal cells in the modulation of thyroid epithelial cells activity, we established and characterized a homogeneous stromal cell population (TS7 cells) of rat thyroid gland. These fibroblastic cells synthesize the cytoskeleton proteins α-smooth muscle actin and vimentin, produce basement membrane components and express the cytokine transforming growth factor beta 1 (TGF-β1). Here, we hypothesized that the effects of E2 on follicular thyroid cells are mediated by TGF-β1 synthesis and secretion by stromal cells (paracrine action). Thus we investigated the effect of E2 on TGF-β1 synthesis and its signaling pathway in TS7 cells. In addition, we analyzed the role of TGF-β1 signaling pathway as mediator of TS7-PC CL3 thyroid epithelial cells interactions. We report that TS7 stromal cells expressed α and β estrogen receptors (ERα and ERβ). Further, both isoforms of TGF-β1 receptors, TGFRI and TGFRII, were also identified in TS7 cells, suggesting that these cells might be a target for this cytokine in vitro. Treatment of TS7 cells with E2 induced both synthesis and secretion of TGF-β1. This event was followed by phosphorylation of the transcription factor Smad2, a hallmark of TGF-β1 pathway activation. Co-culture of PC CL3 cells onto TS7 cells monolayers yielded round aggregates of PC CL3 cells surrounded by TS7 cells. TS7 cells induced a decrease in iodide uptake by PC CL3 cells, probably by a mechanism involving TGF-β1. Moreover, E2 affected synthesis and organization of the extracellular matrix (ECM) components, tenascin C and chondroitin sulfate, in these co-culture cells. Our results point to the TGF-β1/Smad-2 signaling pathway as a putative target of estrogen actions on thyroid stromal cells and contribute to understanding the interplay between stromal and follicular cells in thyroid physiology.

Determination of albendazole metabolites in plasma by HPLC

Albendazole is an antihelminthic agent belonging to the benzimidazole class and has been used successfully in the treatment of neurocysticercosis. We report here a method for the determination of the two major albendazole metabolites in plasma, albendazole sulfone and albendazole sulfoxide. The method consists of drug extraction from 500 microL of plasma previously acidified with chloroform-isopropanol (9:1, v/v) and extract purification with n-hexane immediately before chromatographic analysis. Separation of drugs and of the internal standard (mebendazole) was performed on an RP-18 column using acetonitrile-0.25N sodium acetate buffer (3:7, v/v), pH 5.0, as the mobile phase and using detection at 290 nm.

Thyroid peroxidase inhibition by Kalanchoe brasiliensis aqueous extract

Flavonoids are known inhibitors of thyroid peroxidase (TPO) and some are components of Kalanchoe brasiliensis, a plant used in popular medicine to treat tissue injuries, enlarged ganglia and peptic ulcer. As K. brasiliensis extract is currently used, the present study was designed to evaluate the effects of K. brasiliensis aqueous extract on TPO activity. We show here that TPO iodide-oxidation activity was significantly inhibited by K. brasiliensis aqueous extract and that TPO inhibition seems to be competitive, since the enzyme V(max) was unchanged and K(m) for iodide was significantly increased in the presence of the plant extract. Furthermore, TPO inhibitory activity produced by K. brasiliensis extract was unchanged after boiling or by incubation with hepatic enzymes (activated S9 fraction), suggesting that at least the antithyroid component of this plant infusion could probably reach systemic circulation. We also report that K. brasiliensis aqueous extract is able to scavenge H(2)O(2), in vitro. As H(2)O(2) is an essential TPO cofactor, it is possible that the H(2)O(2) trapping effect of K. brasiliensis may be responsible, at least in part, for the inhibition of the iodide-oxidation reaction catalysed by this enzyme. Thus, K. brasiliensis aqueous extract has antithyroid effects in vitro, suggesting that its chronic consumption could contribute to the development of goitre and hypothyroidism, mainly in areas of low iodine intake.

The impact of the patient post-intensive care syndrome components upon caregiver burden

OBJECTIVE

To evaluate patient post-intensive care syndrome (PICS-P) and caregiver burden 3 months after discharge from the Intensive Care Unit (ICU) and determine the impact of different components of PICS-P upon caregiver burden.

DESIGN

A prospective observational study was conducted over 26 months (January 2013-February 2015).

SETTING

Medical-surgical ICU and follow-up consultation in Portugal.

PATIENTS OR PARTICIPANTS

Patients discharged after a minimum of 2 days in the ICU. Caregiver inclusion criteria: not paid, written and spoken Portuguese, and agreement to participate in the study.

MAIN VARIABLES OF INTEREST

In ICU: Patient gender, age, severity of illness (SAPS II) and length of ICU stay. At 3 months caregiver burden, physical (reduced mobility, weakness acquired in the ICU) and psychological components of PICS (anxiety, depression, post-traumatic stress disorder).

RESULTS

A total of 168 caregivers completed the survey (response rate of 69%). A low degree of overburden was reported by 34.5% of caregivers, while 15.5% showed moderate to high levels of overburden. Patient anxiety and depression 3 months after ICU discharge significantly influenced the presence of caregiver burden (p=0.030 vs p=0.008). When physical components of PICS-P were evaluated, no influence on caregiver burden was observed. Patient demographics, severity of illness and length of stay also failed to influence caregiver burden.

CONCLUSIONS

The presence of psychological components of PICS-P 3 months after ICU seems to have a negative impact upon caregiver burden. On the other hand, physical problems showed no important impact upon caregiver overburden.