Accelerated cell turnover 48 h after intestinal ischemia is NOTCH independent.

AIM OF THE STUDY: Notch signaling plays important roles in maintaining intestinal epithelial homeostasis. When Notch signaling is blocked, proliferation ceases and epithelial cells become secretory. The purpose of the present study was to evaluate the role of Notch signaling pathway following intestinal ischemia-reperfusion (IR) injury in a rat model. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomly divided into four experimental groups: Sham-24 and Sham-48 rats underwent laparotomy and were killed 24 or 48 h later, respectively; IR-24 and IR-48 rats underwent occlusion of SMA and portal vein for 30 min followed by 24 or 48 h of reperfusion, respectively. Enterocyte proliferation and enterocyte apoptosis were determined at killing. Notch-related gene and protein expression were determined using Real Time PCR, Western blotting and immunohistochemistry 48 h followed IR. MAIN RESULTS: IR-48 rats demonstrated significantly increased rates of cell proliferation and increased cell apoptosis in both jejunum and ileum compared to Sham rats. IR-48 rats exhibited a significant decrease in Notch-1 protein expression (Western blot) that was coincided with a significant decrease in the number of Notch-1 positive cells (immunohistochemistry) in jejunum (35% decrease, p < 0.05) and ileum (twofold decrease, p < 0.05) as well as Hes-1 positive cells in jejunum (28% decrease, p < 0.05) and ileum (31% decrease, p < 0.05) compared to Sham-48 rats. CONCLUSIONS: Forty-eight hours following intestinal IR in rats, accelerated cell turnover was associated by inhibited Notch signaling pathway. Intestinal stem cells differentiation toward secretory progenitors rather than differentiation toward absorptive cells is important at this phase of intestinal recovery.

Antioxidant treatment ameliorates germ cell apoptosis induced by a high-dose ionizing irradiation in rats.

BACKGROUND: Exposure to ionizing radiation results in cytotoxic and genotoxic effects caused mainly by the oxidative damage. In the present study, we investigated the radioprotective effect of novel antioxidant cocktail on germ cell apoptosis and spermatogenesis in rats subjected to whole body radiation (WBIR). METHODS: Adult male rats weighing 250-270 g were divided into four groups, eight rats each. Group 1 served as untreated control, group 2 received an IP single dose of antioxidant cocktail (1 ml). Group 3 was exposed to a WBIR (6 Gy). Group 4 received antioxidant cocktail before WBIR. Rats from each group were killed after 48 h. MDA levels were measured in serum (TBARS assay). Johnsen's criteria and the number of germinal cell layers were used to categorize spermatogenesis. TUNEL assay was used to determine germ cell apoptosis. Statistical analysis was performed using one-way ANOVA test. RESULTS: WBIR resulted in histological testicular damage (decrease in Johnsen's criteria, p < 0.05) that was accompanied by a significant increase in germ cell apoptosis, expressed as the number of apoptotic cells per 100 tubules (AI-1 apoptotic index) and the number of positive tubules per 100 tubules (AI-2 apoptotic index). Treatment with antioxidant cocktail resulted in a significant decrease in germ cell apoptosis (33% decrease in AI-1, p < 0.05 and 34% decrease in AI-2, p < 0.05) that was accompanied by an improved spermatogenesis (increase in Johnsen's criteria, p < 0.05). CONCLUSIONS: In a rat model of WBIR, antioxidant treatment ameliorates oxidative stress-induced testicular damage, decreases germ cell apoptosis and improves spermatogenesis.

The role of intermediate filaments in maintaining integrity and function of intestinal epithelial cells after massive bowel resection in a rat.

PURPOSE: Intermediate filaments (IFs) are a part of the cytoskeleton that extend throughout the cytoplasm of all cells and function in the maintenance of cell-shape by bearing tension and serving as structural components of the nuclear lamina. In normal intestine, IFs provide a tissue-specific three-dimensional scaffolding with unique context-dependent organizational features. The purpose of this study was to evaluate the role of IFs during intestinal adaptation in a rat model of short bowel syndrome (SBS). MATERIALS AND METHODS: Male rats were divided into two groups: Sham rats underwent bowel transection and SBS rats underwent a 75% bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined 2 weeks after operation. Illumina's Digital Gene Expression (DGE) analysis was used to determine the cytoskeleton-related gene expression profiling. IF-related genes and protein expression were determined using real-time PCR, Western blotting and immunohistochemistry. RESULTS: Massive small bowel resection resulted in a significant increase in enterocyte proliferation and concomitant increase in cell apoptosis. From the total number of 20,000 probes, 16 cytoskeleton-related genes were investigated. Between these genes, only myosin and tubulin levels were upregulated in SBS compared to sham animals. Between IF-related genes, desmin, vimentin and lamin levels were down-regulated and keratin and neurofilament remain unchanged. The levels of TGF-ß, vimentin and desmin gene and protein were down-regulated in resected rats (vs sham animals). CONCLUSIONS: Two weeks following massive bowel resection in rats, the accelerated cell turnover was accompanied by a stimulated microfilaments and microtubules, and by inhibited intermediate filaments. Resistance to cell compression rather that maintenance of cell-shape by bearing tension are responsible for contraction, motility and postmitotic cell separation in a late stage of intestinal adaptation.

Psychiatric disorders in a cohort of individuals with Prader-Willi syndrome.

BACKGROUND: Psychiatric manifestations in Prader-Willi Syndrome (PWS) are common and often are the most debilitating problem in these individuals. We present an epidemiological nation-wide survey of psychiatric diagnoses in the PWS population, based on full-range psychiatric interviews. METHODS: We studied the distribution of psychiatric diagnoses (as opposed to a symptom-based approach) in the Israel national cohort of adolescents and adults with PWS. There was a total of 53 (32 males) ages 12 years and older. All individuals and their caretakers were interviewed using standardized psychiatric questionnaires. Demographic and clinical variables, Clinical Global Impression (CGI) score, IQ, severity of hyperphagia and quality of life (QOL) were also assessed and correlations with NPD (number of psychiatric diagnoses) calculated. RESULTS: An overwhelming majority (89%) of the study participants had at least one psychiatric diagnosis. The most common were disruptive behavior disorders (DBD) (68%), obsessive compulsive disorder (OCD) (45%) and skin picking (35%). Individuals with DBD were at increased risk for OCD and skin picking. Psychotic disorders were found in 11%. NPD had a significant negative influence on QOL. There was no correlation between NPD and BMI, IQ, hyperphagia severity, hormonal profile or genetic subtypes. CONCLUSIONS: Psychiatric diagnoses are very frequent in PWS and strongly influence QOL. Furthermore, characterizing the profile of psychiatric comorbidity in PWS is crucial for planning effective interventions. Precise behavioral phenotyping in PWS in combination with a well-defined genetic etiology may aid biological research linking biological correlates to behavior.

Accelerated intestinal epithelial cell turnover after bowel resection in a rat is correlated with inhibited hedgehog signaling cascade.

PURPOSE: The hedgehog (Hh) signaling pathway is one of the key regulators of gastrointestinal tract development. Recent studies point to the role of hedgehog signaling in regulating adult stem cells involved in maintenance and regeneration of intestinal stem cells. The purpose of this study was to evaluate the role of Hh signaling during intestinal adaptation in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into two groups: Sham rats underwent bowel transection and SBS rats underwent a 75 % bowel resection. Parameters of intestinal adaptation, enterocyte proliferation, and apoptosis were determined 2 weeks after operation. Illumina's Digital Gene Expression analysis was used to determine the Hh signaling gene expression profiling. Hh-related genes and protein expression were determined using Real-Time PCR, Western blotting, and immunohistochemistry. RESULTS: Massive small bowel resection resulted in a significant increase in enterocyte proliferation and concomitant increase in cell apoptosis. From the total number of 20,000 probes, 13 genes related to Hh signaling were investigated. In jejunum, eight genes were down-regulated, three genes up-regulated, and two genes remained unchanged. In ileum, five genes were down-regulated and six genes were unchanged in SBS vs sham animals. SBS rats also demonstrated a significant three- to fourfold decrease in SMO, GIL, and PTCH mRNA, and protein levels (determined by Real-Time PCR and Western blot) compared to control animals. CONCLUSION: Two weeks following massive bowel resection in rats, the accelerated cell turnover was accompanied by an inhibited Hh signaling pathway. Hh signaling may serve as an important mediator of reciprocal interactions between the epithelium and the underlying mesenchymal stroma during intestinal adaptation following massive bowel resection in a rat.

Fenofibrate reduces intestinal damage and improves intestinal recovery following intestinal ischemia-reperfusion injury in a rat.

PURPOSE: Fenofibrate (FEN) is known as a nuclear receptor activator which regulates many pathophysiological processes, such as oxidative stress, inflammation, and leukocyte endothelium interactions. Recent studies have demonstrated an anti-oxidant, anti-inflammatory, and anti-ischemic role of FEN in the attenuation of ischemia-reperfusion (IR) injury in the kidney, liver, brain, and heart. The purpose of the present study was to examine the effect of FEN on intestinal recovery and enterocyte turnover after intestinal IR injury in rats. METHODS: Male Sprague-Dawley rats were divided into four experimental groups: (1) sham rats underwent laparotomy, (2) sham-FEN rats underwent laparotomy and were treated with intraperitoneal (IP) FEN (20 mg/kg); (3) IR rats underwent occlusion of both the superior mesenteric artery and the portal vein for 30 min followed by 24 h of reperfusion, and (4) IR-FEN rats underwent IR and were treated with IP FEN immediately before abdominal closure. Intestinal structural changes, Park's injury score, enterocyte proliferation, and enterocyte apoptosis were determined 24 h following IR. The expression of Bax, Bcl-2, p-ERK, and caspase-3 in the intestinal mucosa was determined using real-time PCR, Western blot, and immunohistochemistry. RESULTS: Treatment with FEN resulted in a significant decrease in Park's injury score in jejunum (32 %) and ileum (33 %) compared to IR animals. IR-FEN rats also demonstrated a significant increase in mucosal weight in jejunum (23 %) and ileum (22 %), mucosal DNA (38 %) and protein (65 %) in jejunum, villus height in jejunum (17 %) and ileum (21 %), and crypt depth in ileum (14 %) compared to IR animals. IR-FEN rats also experienced significant proliferation rates as well as lower apoptotic indices in jejunum and ileum which was accompanied with higher Bcl-2 levels compared to IR animals. CONCLUSIONS: Treatment with fenofibrate prevents intestinal mucosal damage and stimulates intestinal epithelial cell turnover following intestinal IR in a rat model.

Effect of taurine on intestinal recovery following intestinal ischemia-reperfusion injury in a rat.

PURPOSE: Taurine (TAU) is a sulfur-containing amino acid that is involved in a diverse array of biological and physiological functions, including bile salt conjugation, osmoregulation, membrane stabilization, calcium modulation, anti-oxidation, and immunomodulation. Several studies have established that treatment with TAU significantly protects cerebral, cardiac and testicular injury from ischemia-reperfusion (IR). The purpose of the present study was to examine the effect of TAU on intestinal recovery and enterocyte turnover after intestinal IR injury in rats. METHODS: Male Sprague-Dawley rats were divided into four experimental groups: (1) Sham rats that underwent laparotomy, (2) Sham-TAU rats that underwent laparotomy and were treated with intraperitoneal (IP) TAU (250 mg/kg); (3) IR-rats that underwent occlusion of both superior mesenteric artery and portal vein for 30 min followed by 48 h of reperfusion, and (4) IR-TAU rats that underwent IR and were treated with IP TAU (250 mg/kg) immediately before abdominal closure. Intestinal structural changes, Park's injury score, enterocyte proliferation and enterocyte apoptosis were determined 24 h following IR. The expression of Bax, Bcl-2, p-ERK and caspase-3 in the intestinal mucosa was determined using Western blot and immunohistochemistry. RESULTS: Treatment with TAU resulted in a significant decrease in Park's injury score compared to IR animals. IR-TAU rats also demonstrated a significant increase in mucosal weight in jejunum and ileum, villus height in jejunum and ileum and crypt depth in ileum compared to IR animals. IR-TAU rats also experienced significantly lower apoptotic indices in jejunum and ileum which was accompanied by a higher Bcl-2/Bax ratio compared to IR animals. CONCLUSIONS: Treatment with taurine prevents gut mucosal damage and inhibits intestinal epithelial cell apoptosis following intestinal IR in a rat.

The role of the BMP signaling cascade in regulation of stem cell activity following massive small bowel resection in a rat.

PURPOSE: Bone morphogenetic proteins (BMPs) are a group of growth factors that are implicated in intestinal growth, morphogenesis, differentiation, and homeostasis. The role of the BMP signaling cascade in stimulation of cell proliferation after massive small bowel resection is unknown. The purpose of this study was to evaluate the role of BMP signaling during intestinal adaptation in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into two groups: Sham rats underwent bowel transection and SBS rats underwent a 75 % bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined 2 weeks after operation. Illumina's Digital Gene Expression analysis was used to determine the BMP signaling gene expression profiling. BMP-related genes and protein expression were determined using real-time PCR, Western blotting and immunohistochemistry. RESULTS: From the total number of 20,000 probes, 8 genes related to BMP signaling were investigated. From these genes, five genes were found to be up-regulated in jejunum (BMP1-10 %, BMP2-twofold increase, BMP3-10 %, BMP2R-12 % and STAT3-28 %) and four genes to be up-regulated in ileum (BMP1-16 %, BMP2-27 %, BMP3-10 %, and STAT3-20 %) in SBS vs sham animals with a relative change in gene expression level of 10 % or more. SBS rats also demonstrated a significant increase in BMP2 and STAT3 mRNA and protein levels (determined by real-time PCR and Western blot) compared to control animals. CONCLUSION: Two weeks following massive bowel resection in rats, the BMP signaling pathway is stimulated. BMP signaling may serve as an important mediator of reciprocal interactions between the epithelium and the underlying mesenchymal stroma during intestinal adaptation following massive bowel resection in a rat.

Sexual dichotomy of gonadal function in Prader-Willi syndrome from early infancy through the fourth decade.

STUDY QUESTION: At what age does the type of hypogonadism, namely hypothalamic or primary gonadal defect, become established in men and women with Prader-Willi syndrome (PWS)? SUMMARY ANSWER: The type of hypogonadism becomes established only in late adolescence and early adulthood. WHAT IS KNOWN ALREADY: The etiology of hypogonadism in PWS is heterogeneous and the clinical expression is variable. Primary testicular failure is common in PWS men, while combinations of ovarian dysfunction and gonadotrophin deficiency are seen in women. STUDY DESIGN, SIZE, DURATION: This is a prospective study of a cohort of 106 PWS patients followed for a mean duration of 4.5 years. Serial blood samples were obtained and assayed for gonadotrophins, inhibin B, anti-Mullerian hormone (AMH), dehydroepiandrosterone sulfate (DHEAS), testosterone (males), and estradiol (females). Results were compared with normal reference values obtained from the literature. For the purpose of this study, we defined the following age groups: infants <1 year; children 1-10 years; adolescents 11-20 years and adults >20 years. PARTICIPANTS/MATERIALS, SETTING, METHODS: Study participants were 49 males (aged 2 months to 36 years) and 57 females (aged 1 month to 37 years) with genetically confirmed diagnoses of PWS (deletions 60, uniparental disomy 54, imprinting center defect 2) followed in the Israel national multidisciplinary PWS clinic. MAIN RESULTS AND THE ROLE OF CHANCE: Serum LH levels were in the normal range (1.0-6.0 mIU/ml) for 7/10 adult men, and high in 3, while FSH (normal range 1.0-6.1 mIU/ml) was elevated (34.4 ± 11.5 mIU/ml) in 6 and normal (3.5 ± 1.6 mIU/ml) in 4 men. Testosterone was low (5.7 ± 3.4 nmol/l) compared with the normal range of 12.0-34.5 nmol/l in the reference population in all men >20 years. AMH showed a normal decrease with age, despite low testosterone levels. Inhibin B was normal (241 ± 105 pg/ml) in infant boys, but low or undetectable in most adult men. Hormonal profiles were more heterogeneous in women than in men. Estradiol was consistently detectable in only 7/13 adult women. Inhibin B was low or undetectable in all PWS females although occasional samples showed levels within the normal range of 15-95 pg/ml. Vaginal bleeding was reported to occur for the first time in eight women at a median age of 20 years (13-34 years), but only one had regular monthly menses. The type of hypogonadism (primary or secondary) in PWS can be determined only after age 20 years. LIMITATIONS, REASONS FOR CAUTION: The study cohort was heterogeneous, showing variability in BMI, cognitive disability and medical treatment. WIDER IMPLICATIONS OF THE FINDINGS: Demonstration of the natural history of reproductive hormone development in PWS suggests that androgen replacement may be indicated for most PWS boys in mid-adolescence. Recommendations for hormone replacement in PWS women need to be individually tailored, serial measurements of inhibin B should be performed, and contraception should be considered in those women who may have the potential for fertility.

Genome-wide association study of Tourette's syndrome.

Tourette's syndrome (TS) is a developmental disorder that has one of the highest familial recurrence rates among neuropsychiatric diseases with complex inheritance. However, the identification of definitive TS susceptibility genes remains elusive. Here, we report the first genome-wide association study (GWAS) of TS in 1285 cases and 4964 ancestry-matched controls of European ancestry, including two European-derived population isolates, Ashkenazi Jews from North America and Israel and French Canadians from Quebec, Canada. In a primary meta-analysis of GWAS data from these European ancestry samples, no markers achieved a genome-wide threshold of significance (P<5 × 10(-8)); the top signal was found in rs7868992 on chromosome 9q32 within COL27A1 (P=1.85 × 10(-6)). A secondary analysis including an additional 211 cases and 285 controls from two closely related Latin American population isolates from the Central Valley of Costa Rica and Antioquia, Colombia also identified rs7868992 as the top signal (P=3.6 × 10(-7) for the combined sample of 1496 cases and 5249 controls following imputation with 1000 Genomes data). This study lays the groundwork for the eventual identification of common TS susceptibility variants in larger cohorts and helps to provide a more complete understanding of the full genetic architecture of this disorder.

Accidental injuries are more common in children with attention deficit hyperactivity disorder compared with their non-affected siblings.

BACKGROUND: Accidental injuries are a leading cause of paediatric morbidity and mortality. We hypothesized that attention deficit hyperactivity disorder (ADHD), a common childhood disorder characterized by behaviours such as hyperactivity and impulsivity, is a risk factor for accidental injuries. Previous retrospective studies suggested that children with ADHD have an increased injury rate, but controlled prospective studies are lacking. METHODS: We conducted a prospective case-control study of 29 school-aged children with ADHD and their same-sex, similarly aged, non-ADHD-affected siblings. All diagnoses were made by a paediatric neurologist according to DSM-IV criteria and the children and their parents underwent a structured psychiatric interview and a battery of complementary assessments including: Child Behavior Checklist (CBCL), ADHD Rating scale and Developmental Coordination Disorder Questionnaire (DCDQ). The parents were contacted by telephone every 3 months during a 9-month follow-up period and all injuries requiring medical attention were recorded. Incidence of injuries was compared between the pairs of siblings. RESULTS: During the follow-up period, a total of 13 injuries in 13 children with ADHD were reported, compared with six injuries in six children from the control group (Z=-2.11, P < 0.05). ADHD severity and subtype, CBCL, DCDQ and IQ scores were not predictive of injury risk. CONCLUSIONS: School-aged children with ADHD are at higher risk of accidental injuries than their non-ADHD siblings, regardless of ADHD subtype, co-morbid psychiatric conditions, developmental co-ordination problems and environmental/familial conditions. Awareness and adequate education of parents and caregivers of children with ADHD concerning the increased injury risks are thus warranted.

Why do young women smoke? VI. A controlled study of nicotine effects on attention: pharmacogenetic interactions.

In prior studies we found that young, female smokers manifest poorer performance than non-smokers on attention-related tasks and that these findings can be moderated by variation in nicotinic acetylcholine receptor (nAChR) genes. We predicted that under controlled conditions (1) nicotine would improve functioning on attentional tasks in smokers who previously manifested relatively poor performance, and that (2) smokers who carry genetic variations associated with poorer attention performance would derive greater benefit from nicotine. To test these hypotheses, 31 young female smokers, who participated in our previous study, performed the Matching Familiar Figures Test (MFFT), Tower of London Test and Continuous Performance Task (CPT) in a double-blind, within-between subject design, placebo or nicotine (4 mg as gum) serving as the within factor and genetic profile as the between factor. Repeated measures ANCOVA controlling for attention deficit symptomatology, substance abuse and nicotine dependence showed better performance under nicotine among participants with higher levels of attention deficit symptoms (MFFT errors: P=0.04; CPT commissions: P=0.01) and nicotine dependence (CPT stability of response: P=0.04) and greater consumption of caffeine (CPT stability of response: P=0.04). An interactive effect of genetic profile was demonstrated for SNP rs2337980 in CHRNA7. These findings suggest that nicotine may have stronger short-term facilitating effects on attention in women who have more attention deficit symptoms and consume more nicotine and caffeine. This effect may be modified by a specific genetic make-up. Such individuals may be at increased risk for nicotine addiction and for greater difficulties in smoking cessation.

Testing possible mechanisms of deficient supra-second time estimation in adults with attention-deficit/hyperactivity disorder.

Numerous studies indicate deficient time estimation in individuals with attention-deficit/hyperactivity disorder (ADHD). Several hypotheses have been raised to explain this deficit including delay aversion, vulnerability to nontemporal distractions, deficient working memory, as well as pure deficit in temporal processing. To test the different hypotheses, adults with or without ADHD performed a prospective time-estimation task under different conditions: with or without nontemporal distraction; and with or without increased load of working memory. Such design was used to rule out the effect of motor control and to manipulate the hypothesized mechanisms of working memory and attention to nontemporal stimuli. The authors report that compared with the control group, adults with ADHD showed greater and more variable deviation in time estimation. In addition, the magnitude of time estimation was affected by allocation of attention to nontemporal stimuli and by load of working memory. The intraindividual variability of time estimation was only partially accounted for by load of working memory. These findings suggest that the ADHD-associated deficit in prospective time estimation is not attributable to special attention to nontemporal stimuli or compromised working memory.

Retrieval processes in adults with ADHD: a RAVLT study.

Attention-deficit hyperactivity disorder (ADHD) is associated with memory deficiencies. In the current study we compared different aspects of verbal memory using standard and constructed measures of the Rey auditory verbal learning test (RAVLT). Performance on learning and recognition measures of RAVLT was similar in both ADHD and control groups. In contrast, adults with ADHD committed more double recalls and intrusion errors, indicating inaccurate recall processes. These findings suggest that memory problems in adults with ADHD may be caused by deficient executive processes that support retrieval from memory.

Why do young women smoke? V. Role of direct and interactive effects of nicotinic cholinergic receptor gene variation on neurocognitive function.

Previous work suggests that young women who smoke cigarettes regularly, or did so in the past, manifest a neurocognitive profile that is characterized by small but significant impairments of response inhibition and attention. The present study sought to determine whether variation in nicotinic cholinergic receptor (nAchR) genes impacts upon cognitive function in these domains by overall or differential effects on the performance of current, former and non-smokers. The study sample consisted of 100 female college students, current or past smokers, and 144 who had never smoked. All performed a computerized neurocognitive test battery and were genotyped for 39 single nucleotide polymorphisms in 11 nAchR genes. The results, derived from linear or logistic regression, show significant direct and interactive relationships between single nucleotide polymorphisms and haplotypes in several nAchR genes and performance on the Matching Familiar Figures Test (MFFT) Stroop test, Continuous Performance Task (CPT) and Tower of London (TOL) test. Response inhibition (MFFT, Stroop, CPT Loading Phase, TOL) was associated with variants in CHRNA2, CHRNA4, CHRNA5, CHRNA7, CHRNA9, CHRNA10, CHRNB2 and CHRNB3. Selective attention (Stroop) was associated with CHRNA4, CHRNA5, CHRNA9 and CHRNB2. Sustained attention (CPT Boring Phase) was associated with CHRNA4, CHRNA5, CHRNA7, CHRNA10 and CHRNB3. Up to 37% of the variance among the smokers and up to 47% of the variance among the non-smokers on the test measures was explained. Differences between smokers and non-smokers in neurocognitive function, putatively implicated in susceptibility to nicotine dependence, may be modulated by variants in nAchR genes, with potential implications for prevention and treatment.

Assessment of thyroid function in dogs with low plasma thyroxine concentration.

BACKGROUND: Differentiation between hypothyroidism and nonthyroidal illness in dogs poses specific problems, because plasma total thyroxine (TT4) concentrations are often low in nonthyroidal illness, and plasma thyroid stimulating hormone (TSH) concentrations are frequently not high in primary hypothyroidism. HYPOTHESIS: The serum concentrations of the common basal biochemical variables (TT4, freeT4 [fT4], and TSH) overlap between dogs with hypothyroidism and dogs with nonthyroidal illness, but, with stimulation tests and quantitative measurement of thyroidal 99mTcO4(-) uptake, differentiation will be possible. ANIMALS: In 30 dogs with low plasma TT4 concentration, the final diagnosis was based upon histopathologic examination of thyroid tissue obtained by biopsy. Fourteen dogs had primary hypothyroidism, and 13 dogs had nonthyroidal illness. Two dogs had secondary hypothyroidism, and 1 dog had metastatic thyroid cancer. METHODS: The diagnostic value was assessed for (1) plasma concentrations of TT4, fT4, and TSH; (2) TSH-stimulation test; (3) plasma TSH concentration after stimulation with TSH-releasing hormone (TRH); (4) occurrence of thyroglobulin antibodies (TgAbs); and (5) thyroidal 99mTcO4(-) uptake. RESULTS: Plasma concentrations of TT4, fT4, TSH, and the hormone pairs TT4/TSH and fT4/TSH overlapped in the 2 groups, whereas, with TgAbs, there was 1 false-negative result. Results of the TSH- and TRH-stimulation tests did not meet earlier established diagnostic criteria, overlapped, or both. With a quantitative measurement of thyroidal 99mTcO4(-) uptake, there was no overlap between dogs with primary hypothyroidism and dogs with nonthyroidal illness. CONCLUSIONS AND CLINICAL IMPORTANCE: The results of this study confirm earlier observations that, in dogs, accurate biochemical diagnosis of primary hypothyroidism poses specific problems. Previous studies, in which the TSH-stimulation test was used as the "gold standard" for the diagnosis of hypothyroidism may have suffered from misclassification. Quantitative measurement of thyroidal 99mTcO- uptake has the highest discriminatory power with regard to the differentiation between primary hypothyroidism and nonthyroidal illness.

Multimodality image fusion to facilitate anatomic localization of 99mTC-pertechnetate uptake in the feline head.

99mTc-pertechnetate is excreted in humans by the thyroid glands, gastric mucosa, salivary glands, choroid plexus, and sweat glands. Uptake attributed to the zygomatic and molar salivary glands is used commonly as a reference to assess thyroid uptake and differentiate euthyroid from hyperthyroid cats. However, the exact location and origin of uptake of 99mTc-pertechnetate in the head during thyroid scintigraphy in cats remains uncertain. The purpose of this study was to localize uptake of 99mTc-pertechnetate in the head of the cat using multimodality image fusion. Computed tomography (CT), magnetic resonance (MR), and single photon emission tomography (SPECT) imaging were performed successively in two cats during the same anesthesia procedure. Transverse, dorsal, and sagittal images were reconstructed for each modality. Images were rescaled and fused manually. The anatomic location of focal 99mTc activity in SPECT images was identified in CT and MR images. Four major and four minor focal areas of uptakes were identified in the head in both cats. A rostral conical-shaped activity was identified in the nasal cavity. Two symmetric focal areas of uptakes seen in the soft tissues in the ventro-caudal retro-bulbar region, and rostro-medial to the vertical ramus of the mandible were attributed to zygomatic salivary glands. A central focal activity located ventral and caudal to the zygomatic uptake was located in the nasopharynx and soft palate. Minor symmetric areas of uptake identified in the retromandibular region were attributed to parotid and mandibular salivary glands. Minor symmetric areas of uptake identified in the region of the mandible were attributed to molar salivary glands. No focal area of uptake was identified in the brain.

The EAE-associated behavioral syndrome: I. Temporal correlation with inflammatory mediators.

To elucidate the mechanisms underlying the EAE-associated behavioral syndrome (EBS), we examined the temporal correlation between the behavioral alterations and inflammatory processes. Onset of the behavioral syndrome was associated with the onset of brain infiltration, as well as mRNA expression of interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha) and elevated production of interleukin 1 beta protein and prostaglandin E(2) (PGE(2)). Sickness behavior symptoms coincided with peak cytokine expression. Behavioral recovery was associated with a reduction of cytokine expression, but not infiltration, PGE(2) production or motor disturbances. These results suggest that inflammatory processes in general, and the production of pro-inflammatory cytokines in particular, are involved in mediating EAE-associated sickness behavior.

The EAE-associated behavioral syndrome: II. Modulation by anti-inflammatory treatments.

EAE is associated with sickness behavior symptoms that are temporally correlated with inflammatory processes. To further elucidate the role of inflammatory mediators in the behavioral syndrome, EAE mice were injected daily with anti-inflammatory drugs, beginning at disease onset. Dexamethasone or interleukin-1 (IL-1) receptor antagonist or the prostaglandins synthesis inhibitor indomethacin attenuated the behavioral symptoms. Administration of the tumor necrosis-factor alpha (TNF-alpha) synthesis inhibitor pentoxifylline or targeted deletion of the type I TNF receptor had no behavioral effects whereas administration of pentoxifylline in IL-1ra-treated mice further reversed the behavioral depression. These findings demonstrate the critical involvement of pro-inflammatory cytokines and prostaglandins in the EAE-associated behavioral syndrome, and may have implications for understanding and treating the neuropsychiatric disturbances in multiple sclerosis (MS) patients.

Experimental autoimmune encephalomyelitis-associated behavioral syndrome as a model of 'depression due to multiple sclerosis'.

Many medical conditions, including inflammatory diseases such as multiple sclerosis (MS), are often accompanied by a high prevalence of depressive episodes. Inflammatory mediators, such as cytokines, were implicated in illness-associated depressive conditions, both in humans and in animals. For example, MS-associated depression (MSD) was attributed to pathophysiological processes such as immune dysregulation and cerebral inflammation. We have recently documented a depressive-like behavioral syndrome in mice with experimental autoimmune encephalomyelitis (EAE), an established model of MS. In the present paper, we discuss the similarities between the EAE-associated behavioral syndrome (EBS) and MSD, in terms of phenomenology, putative mechanisms and responsiveness to anti-depressive therapy. In particular, we show that: (1) EAE and depression are associated not only with similar behavioral symptomatology, but also with common physiological alterations, including impaired serotonergic neurotransmission, and activation of neuroendocrine (e.g., adrenocortical) and inflammatory cytokine systems; (2) the EBS precedes any neurological deficit during the initial EAE attack, as well as further exacerbations, and remits during recovery and between relapses. Similarly, in many MS patients depression precedes and accompanies the attacks and wanes during remissions; (3) females show increased susceptibility to EBS. Similarly, depression is much more prevalent in women than in men; (4) chronic treatment with the tricyclic anti-depressant imipramine reduced EAE-induced mortality, body-weight loss and behavioral suppression. Similarly, anti-depressant drugs have been used effectively in treating MSD. These findings suggest that the EBS may serve as an animal model for MSD.