Effects of attentional focus and gaze instruction during observational learning of a basketball free-throw

Observational learning has long been used to instruct individuals on how to perform a novice motor skill. Recently, research has shown a benefit to instructing learners to focus externally when viewing a video model (Asadi, Aiken, Heidari, & Kochackpour, 2021). Research has also highlighted the effectiveness of modeling correct gaze behaviors when learning a cognitive task (Jarodzka, van Gog, Dorr, Scheiter, & Gerjets, 2013). The purpose of the present study was to investigate the effectiveness of combining these two modalities. 40 individuals with a mean age of 21.77 ± 1.40 performed a novel motor task where they were asked to either focus internally or externally, and were provided with traditional instruction or were provided with an experienced performer's gaze behaviors while viewing a video demonstration. It was observed that both the external focus groups and the gaze instructed groups performed a basketball free-throw more accurately and had longer periods of quiet eye than an internal focus or traditional verbal instruction (p's < 0.05). Eye tracking also allowed for the assessment of attentional focus adherence. Participants focused on the instructed cues significantly more than irrelevant task aspects or a different focus types (p's < 0.05). These results highlight the effectiveness of cuing a learner to focus externally during observational learning. It also highlights the usefulness of providing correct gaze behaviors when observing a model.

The role of vitamin D in the age of COVID-19: A systematic review and meta-analysis

BACKGROUND

Evidence recommends that vitamin D might be a crucial supportive agent for the immune system, mainly in cytokine response regulation against COVID-19. Hence, we carried out a systematic review and meta-analysis in order to maximise the use of everything that exists about the role of vitamin D in the COVID-19.

METHODS

A systematic search was performed in PubMed, Scopus, Embase and Web of Science up to December 18, 2020. Studies focused on the role of vitamin D in confirmed COVID-19 patients were entered into the systematic review.

RESULTS

Twenty-three studies containing 11 901 participants entered into the meta-analysis. The meta-analysis indicated that 41% of COVID-19 patients were suffering from vitamin D deficiency (95% CI, 29%-55%), and in 42% of patients, levels of vitamin D were insufficient (95% CI, 24%-63%). The serum 25-hydroxyvitamin D concentration was 20.3 ng/mL among all COVID-19 patients (95% CI, 12.1-19.8). The odds of getting infected with SARS-CoV-2 are 3.3 times higher among individuals with vitamin D deficiency (95% CI, 2.5-4.3). The chance of developing severe COVID-19 is about five times higher in patients with vitamin D deficiency (OR: 5.1, 95% CI, 2.6-10.3). There is no significant association between vitamin D status and higher mortality rates (OR: 1.6, 95% CI, 0.5-4.4).

CONCLUSION

This study found that most of the COVID-19 patients were suffering from vitamin D deficiency/insufficiency. Also, there is about three times higher chance of getting infected with SARS-CoV-2 among vitamin-D-deficient individuals and about five times higher probability of developing the severe disease in vitamin-D-deficient patients. Vitamin D deficiency showed no significant association with mortality rates in this population.

The effect of attentional instructions during modeling on gaze behavior and throwing accuracy in 7 to 10 year-old children

Research has shown the effectiveness of attentional instructions and observation on the performance and learning in children. However, there is little research on the effects of instruction that manipulates attentional focus during observation. The purpose of the study was to investigate performance following instructions that directed an individual to focus internally or externally during the viewing of a model. Eye tracking was also used to investigate the visual search strategy under different instructional groups. 24 children between the ages of 7 and 10 years were randomly divided into an internal (IFM) or external (EFM) modeling group. Children performed a 10-trial pre-test to measure throwing accuracy and quiet eye duration (QED). Following pre-test, children observed a model performing the correct overarm throw 10 times while eye movement was recorded. They then performed a 10-trial post-test. Results revealed that both groups improved accuracy from pre-test to post-test (p < .001) and increased QED from pre- to post-test (p < .001). It was also observed that EFM had greater accuracy and (p = .01) and longer QED (p < .001) than IFM during post-testing. Evidence was also observed for adherence to the attentional focus strategy as EFM and IFM looked more frequently at the specific cue provided (p < .001). Directing visual attention to the movement effects while observing a model significantly benefits motor performance and learning in children. Changing the focus of instruction to an external focus improved both throwing accuracy and increased QED.

Drug-Drug Interaction between Psychiatric Medications and Experimental Treatments for Coronavirus Disease-19: A Mini-Review

The pandemic of coronavirus disease (COVID)-2019 has been affected many people all around the world. Patients with mental disorders are not as safe as others; also, they might be more vulnerable in such situations. These patients take various medications, which can lead to numerous drug-drug interactions with experimental drugs uses against COVID-19. According to the potential critical interactions, we reviewed the reputable databases to find the interactions between main categories of psychiatric medications (e.g., antidepressants, anti-psychotics, sedative/hypnotics, and mood stabilizers) when used in concomitant with COVID-19 experimental agents (e.g., hydroxychloroquine, lopinavir/ritonavir, atazanavir, and chloroquine). We hope the list provided in this review helps the clinical care staff in treating patients with mental illness infected with severe acute respiratory syndrome coronavirus 2 during the COVID-19 pandemic.

A 3'-untranslated region variant (rs2289046) of insulin receptor substrate 2 gene is associated with susceptibility to nonalcoholic fatty liver disease

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is an increasing global health concern defined by excessive hepatic fat content in the absence of excessive alcohol consumption. Regarding the key role of insulin and insulin resistance in NAFLD, we investigated whether insulin receptor substrate 1 (IRS1) and insulin receptor substrate 2 (IRS2) gene variants were associated with NAFLD risk.

METHODS

In this case-control study, 305 subjects including 151 cases with biopsy-proven NAFLD and 154 controls were enrolled. All the subjects were genotyped for IRS1 (rs1801278) and IRS2 (rs2289046) gene variants using PCR-RFLP method.

RESULTS

Our findings showed that the IRS2 rs2289046 "GG+AG" genotype compared with "AA" genotype to be a marker of decreased NAFLD susceptibility and the difference remained significant even after adjustment for confounding factors including age, BMI, sex, smoking status, systolic blood pressure, and diastolic blood pressure (P=0.014; OR=0.50, 95%CI= 0.29-0.87). Furthermore, the IRS2 "G" allele was significantly underrepresented in the cases with NAFLD than controls (P=0.026 ; OR=0.62, 95%CI=0.41-0.94). However, no significant difference was found for IRS1 rs1801278 gene variant.

CONCLUSIONS

This study suggests, for the first time, that the IRS2 gene rs2289046 variant may play a role in NAFLD susceptibility. Nevertheless, this observation warrants further investigations in other populations.

Evaluation of Hepatitis B Vaccination among Lichen Planus Patients

Lichen planus (LP) is an idiopathic chronic inflammatory mucocutaneous disease. Many reports in the literature have described hepatitis B vaccine as a predisposing factor for LP. This study was performed to determine the rate of previous vaccination against hepatitis B in LP patients. This was a cross sectional study on LP patients. Diagnosis of LP was confirmed by histological examination. Data were gathered by dermatology residents based on a checklist designed to guide their interview. Blood samples were tested for HBsAB titer, HBsAg, HCV Ab and liver function tests. One hundred & twenty four (124) patients entered the study. Females were 2.72 times more affected. The mean age of patients was 45.63 years (age range; 18-88). Forty-four (35.5%) patients had been vaccinated against hepatitis B. Lichen planus during the first six months of vaccination occurred in only one patient. Our findings bring into question the causative role of HBV vaccine in LP incidence in our population.

Responding to physical and psychological health impacts of disasters: case study of the Iranian disaster rehabilitation plan

This paper describes the process of developing a national pre-disaster plan for physical health and psychological rehabilitation of disaster-stricken communities. Data gathered from a literature review and expert panel discussions informed the process of drawing up unified definitions of physical and psychological health rehabilitation, carrying out stakeholder and STEEP-V analyses, and assigning the responsible organization and the collaborative organizations for each task. The Ministry of Health and the Welfare Organization were selected as the two responsible organizations. Integrated management at all levels, and sharing information, education and funding, were identified as ways to improve stakeholders' participation and collaboration. A system is needed for evaluating the implementation of the disaster rehabilitation plan, using valid and reliable indicators.

Nitrogen removal by ANAMMOX and simultaneous nitrification–denitrification (SND) processes in a novel single airlift bioreactor

The aim of this research was to assess anaerobic ammonium oxidation and simultaneous nitrification–denitrification processes in a novel continuous feed and intermittent discharge airlift bioreactor which provides anaerobic, anoxic and aerobic zones by physical separation.

High rate CNP removal from a milk processing wastewater in a single ultrasound augmented up-flow anaerobic/aerobic/anoxic bioreactor

Simultaneous removal of carbon, nitrogen and phosphorus (CNP) in a single bioreactor is of high significance in terms of reactor volume and energy consumption. Therefore, in this study, an innovative up-flow anaerobic/aerobic/anoxic bioreactor (UAAASB) augmented by ultrasound was developed as a high rate single bioreactor for the simultaneous removal of nutrients from a milk processing wastewater. The ultrasonic irradiation used in this work was in the range of high frequency (1.7 MHz). The central composite design (CCD) and response surface methodology (RSM) were applied to design the experimental conditions, model obtained data, and optimize the process. The effects of three independent variables, i.e. hydraulic retention time (HRT), aeration mode and mixed liquor suspended solid (MLSS) concentration on 10 process responses were investigated. The results prove that the ultrasonic irradiation has a positive effect on the sludge settling velocity and effluent turbidity. The optimum conditions were determined as 12-15 h, 4000-5000 mg/l and 1.5-2 for HRT, MLSS concentration and aeration mode, respectively, based on removal efficiency of sCOD ⩾ 90%, TN and TP ⩾ 50%.

Performance of intermittently aerated up-flow sludge bed reactor and sequencing batch reactor treating industrial estate wastewater: a comparative study

In this study, an innovative aerobic/anoxic sludge bed bioreactor with two feeding regimes, continuous-fed (an up-flow sludge bed reactor (USBR)) and batch fed (sequencing batch reactor (SBR)), was evaluated for the treatment of an industrial estate wastewater with low BOD(5)/COD ratio. The process performance in the two regimes was compared. Two numerical independent variables (retention/react time and aeration time) were selected to analyze, model and optimize the process. Response surface methodology with central composite design (CCD) was used with five levels of hydraulic retention time (HRT)/react time (12-36h) and aeration time (40-60min/h). In order to analyze the process, ten dependent parameters as the process responses were studied. As a result, HRT/react time showed a decreasing impact on the responses measured in both hydraulic regimes, USBR and SBR. The USBR showed better performance than the SBR in removal of total COD, slowly biodegradable COD, total nitrogen and total Kjeldahl nitrogen.

Simultaneous removal of carbon and nutrients from an industrial estate wastewater in a single up-flow aerobic/anoxic sludge bed (UAASB) bioreactor

Simultaneous removal of carbon and nutrients (CNP) in a single bioreactor is highly significant for energy consumption and control of reactor volume. Basically, nutrients removal is dependant to the ratio of biochemical oxygen demand to chemical oxygen demand (BOD₅/COD). Thus, in this study the treatment of an industrial estate wastewater with low BOD₅/COD ratio in an up-flow aerobic/anoxic sludge bed (UAASB) bioreactor, with an intermittent regime in aeration and discharge, was investigated. Hydraulic retention time (HRT) of 12-36 h and aeration time of 40-60 min/h were selected as the operating variables to analyze, optimize and model the process. In order to analyze the process, 13 dependent parameters as the process responses were studied. From the results, it was found, increasing HRT decreases the CNP removal efficiencies. However, by increasing the BOD₅ fraction of the feed, the total COD (TCOD), slowly biodegradable COD (sbCOD), readily biodegradable COD (rbCOD), total nitrogen (TN), and total phosphorus (TP) removal efficiencies were remarkably increased. Population of heterotrophic, nitrifying and denitrifying bacteria showed good agreement with the results obtained for TCOD and TN removal. The optimum conditions were determined as 12-15 h and 40-60 min/h for HRT and aeration time respectively.

Immunohistochemical characterisation of cells co-producing insulin and glucagon in the developing human pancreas

AIMS/HYPOTHESIS

In adult human islets, insulin and glucagon production is largely restricted to individual cell populations. The production of these hormones is less segregated during development and during the differentiation of human pluripotent stem cells towards pancreatic lineages. We therefore sought to characterise the transcription factor profile of these cells that co-produce insulin and glucagon in the developing human pancreas, and thus to gain insight into their potential fate during normal pancreas development.

METHODS

An immunohistochemical analysis was performed on human pancreas sections from fetal donors aged 9 to 21 weeks and from adult donors between the ages of 17 and 55 years.

RESULTS

Endocrine cells were observed within the pancreas at all ages examined, with cells co-producing insulin and glucagon observed as early as 9 weeks of fetal age. The population of cells that co-produce insulin and glucagon generally decreased in prevalence with age, with negligible numbers in adult pancreas. From 9 to 16 weeks, the population of glucagon-only cells increased, while the insulin-only cells decreased in abundance. Cells that co-produced insulin and glucagon also produced the alpha cell transcription factor, aristaless related homeobox (ARX), and lacked the beta cell transcription factors pancreatic and duodenal homeobox 1 (PDX1), NK6 homeobox 1 (NKX6.1) and v-maf musculoaponeurotic fibrosarcoma oncogene homologue A (MAFA).

CONCLUSIONS/INTERPRETATION

Our results indicate that cells co-producing insulin and glucagon in the developing human pancreas share a transcription factor profile that is similar to that of mature alpha cells and suggest that some maturing alpha cells briefly exhibit ectopic insulin expression. Thus cells that co-produce insulin and glucagon may represent a transient cell population, which gives rise to mature alpha cells.

Musashi expression in β-cells coordinates insulin expression, apoptosis and proliferation in response to endoplasmic reticulum stress in diabetes

Diabetes is associated with the death and dysfunction of insulin-producing pancreatic β-cells. In other systems, Musashi genes regulate cell fate via Notch signaling, which we recently showed regulates β-cell survival. Here we show for the first time that human and mouse adult islet cells express mRNA and protein of both Musashi isoforms, as well Numb/Notch/Hes/neurogenin-3 pathway components. Musashi expression was observed in insulin/glucagon double-positive cells during human fetal development and increased during directed differentiation of human embryonic stem cells (hESCs) to the pancreatic lineage. De-differentiation of β-cells with activin A increased Msi1 expression. Endoplasmic reticulum (ER) stress increased Msi2 and Hes1, while it decreased Ins1 and Ins2 expression, revealing a molecular link between ER stress and β-cell dedifferentiation in type 2 diabetes. These effects were independent of changes in Numb protein levels and Notch activation. Overexpression of MSI1 was sufficient to increase Hes1, stimulate proliferation, inhibit apoptosis and reduce insulin expression, whereas Msi1 knockdown had the converse effects on proliferation and insulin expression. Overexpression of MSI2 resulted in a decrease in MSI1 expression. Taken together, these results demonstrate overlapping, but distinct roles for Musashi-1 and Musashi-2 in the control of insulin expression and β-cell proliferation. Our data also suggest that Musashi is a novel link between ER stress and the compensatory β-cell proliferation and the loss of β-cell gene expression seen in specific phases of the progression to type 2 diabetes.

Significance of blood-related high-risk behaviors and horizontal transmission of hepatitis B virus in Iran

Hepatitis B virus (HBV) is a significant public health problem and a leading cause of morbidity and mortality, and approximately 30% of the world's population is infected with HBV. The objective of our study was to determine the seroprevalence of HBV and major risk factors associated with its occurrence. Four thousand eighty-seven healthy Iranian subjects aged 8-80 years were screened for HBV serological markers by an enzyme immunoassay method. A structured questionnaire was administered to all participants. Multiple logistic regression, an unpaired t-test for continuous data and the χ (2) test for categorical data were performed. A total of 4087 participants were tested for hepatitis B surface antigen (HBsAg), of which 62 (1.5%) were seropositive. Fifteen percent of the subjects were positive for anti-HBs, 6.3% were positive for isolated anti-HBc and 12.5% were positive for both anti-HBs and anti-HBc. Laborers showed a higher HBsAg(+) seroprevalence and risk compared with jobless participants (Pearson's = 8.276, P = 0.004; OR = 4.1, 95% CI: 1.5-11.2). Bivariate logistic regression revealed that the following variables were significantly associated with HBV seropositivity: phlebotomy (P = 0.002; OR = 5.0, 95% CI: 2.1-11.9), tattooing (P = 0.003; OR = 3.4, 95% CI: 1.6-7.0), intravenous drug use (P = 0.001; OR = 2.4, 95% CI: 1.4-4.1). The adjusted prevalence ratios remained significantly associated with HBV seropositivity and thus likely served as possible risk factors for HBV. The overall positive seroprevalence was 1.5%. Among the variables, only phlebotomy, tattooing and intravenous drug injection emerged as major potential risk factors for hepatitis B infection and responsible for transmission of the disease.

Preparation of antibody against horseradish peroxidase using hybridoma technology

BACKGROUND

Monoclonal antibody against horseradish peroxidase (HRP) has many applications which peroxidase anti-peroxidase. Peroxidase-antiperoxidase (PAP) complex formation is its most known and important usage. This complex is used in many immunohistochemical and immunocytochemical staining techniques.

OBJECTIVE

The aim of this study was the preparation of anti-HRP monoclonal antibody through hybridoma technology.

METHODS

The BALB/c mice were immunized by repeated injections of HRP. After the confirmation of their immunization by ELISA test, the spleen lymphocytes and SP2/0 myeloma cells were hybridized using PEG as fusing agent. The hybridoma cells were then selected by culturing in HAT medium. Identification and selection of anti-HRP producing clones were done by ELISA test on culture supernatants of the obtained clones. To acquire the monoclones, limiting dilution was performed twice and the effect of finally obtained antibodies on enzyme activity was investigated by a specific ELISA test. In vivo tumor induction method was used for production of concentrated antibody. At last class and subclass of the obtained antibodies were determined by Isostrip Kit.

RESULTS

After seven rounds of cell fusions, 224 clones were obtained, from which, six ones were anti-HRP producers. Two clones (P1F11 and P2F6) with higher antibody secretion were selected and subcloned. Both derived hybridoma monoclones (P1F11D2 and P2F6F3) were producing antibodies from IgG1 subclass with kappa (Kappa) light chains which didn't affect the enzyme activity. The electrophoresis of ascetic fluid of tumor induced mice showed an obvious band in gamma (gamma) position.

CONCLUSION

The obtained monoclonal antibodies are from IgG class and don't affect the enzyme activity, therefore it seems that they are suitable for PAP complex production.

ESDN is a marker of vascular remodeling and regulator of cell proliferation in graft arteriosclerosis

Vascular remodeling is a common feature of many vasculopathies, including graft arteriosclerosis (GA). We investigated whether endothelial and smooth muscle cell-derived neuropilin-like protein (ESDN) is a marker of vascular remodeling in GA. Immunostaining of human coronary arteries demonstrated high levels of ESDN in GA, but not in normal arteries. In a model of GA, where a segment of human coronary is transplanted into a severe combined immunodeficient mouse, followed by allogeneic human peripheral blood mononuclear cell (PBMC) reconstitution, ESDN was minimally expressed in transplanted human arteries in the absence of reconstitution. By 2 weeks following PBMC reconstitution, at a time corresponding to maximal vascular cell proliferation, high levels of ESDN were detected in the transplanted arteries. Similarly, injury-induced vascular remodeling in apoE(-/-) mice was associated with early and transient ESDN upregulation, in parallel with cell proliferation. In vascular smooth muscle cell (VSMC) cultures, ESDN expression was significantly higher in proliferating, as compared to growth-arrested cells. ESDN overexpression in VSMC led to a decline in growth curves, while ESDN knock down had the opposite effect. We conclude that ESDN is a marker of vascular remodeling and regulator of VSMC proliferation. ESDN may serve as a therapeutic or diagnostic target for GA.

Knowledge, attitudes and sources of information regarding HIV/AIDS in Iranian adolescents

The World Health Organization recently reported an 'alarming trend' of increasing Human Deficiency Virus (HIV) infection in the Islamic Republic of Iran. Adolescents form a particularly important target group for primary prevention. An anonymous questionnaire, derived from standard surveys such as the Safer Choices questionnaire and the 2001 Youth Risk Behavior Survey, was distributed to 1227 Iranian students attending 19 randomly selected high schools in Hashtgerd in 2002. Students reported that television (84%) and school teachers (66%) were the best sources of HIV/AIDS information, while parents (27%) and school books (15%) were least informative. Most students knew that heterosexual intercourse (90%) and shared intravenous needles (94%) can cause HIV infection; however, salient misconceptions were revealed. Only 53% were aware that condoms protect against infection through sexual intercourse. More effective school-based HIV/AIDS education is needed in Iran.

Prevalence and distribution of peripheral nerve injuries in victims of Bam earthquake

INTRODUCTION

In the early morning of Friday 25th Dec. 2003, the ancient and historical city of Bam in Southern East of Iran was vibrated by a big and horrible earthquake for 6.4 degree of Richter. About 30,000 people were died and about 30,000 victims and injured persons were the initial results of the earthquake. Almost all of the buildings were destroyed and all the people became houseless. In this study, 156 patients with peripheral nerve lesion (PNL) were assessed for their injuries.

MATERIALS AND METHODS

In a cross sectional study since the second week after the quake until 6 months later, we examined 506 patients with the symptoms and signs of motor/sensory and performed the Electrodiagnostic study for all of the patients who had obvious or suspected lesion of peripheral nerves. There were 156 patients (31.2%) afflicted with peripheral nerve lesion. We performed NCS/EMG for upper limb and face at least 2 weeks and for lower limb, at least 3 weeks after injury in 156 of the victims that had PNL.

FINDINGS

Of 156 patients, 75 (48%) were female and 81 (52%) were male. The average of age was 29.2 +/- 12.9 years, about 87.2% were between 15 to 50 yrs old. The frequency of injuries was 88 nerves, 53 neural plexuses and 5 cauda equina lesions. The most frequent injured nerve was sciatic nerve (24.8%) and the next was Radial nerve (15.5%) and the less frequent nerve was axillary which observed just in 1 patient. 21.6% of patients had the brachial plexus and/or lumbosacral plexus injuries. There were more involvements in lower limbs comparing upper limbs and face (p < 0.01).

CONCLUSION

Peripheral nerve injury is one of the most frequent injuries in earthquake victims. These lesions may cause temporary or lifelong disabilities in patients. In this study, the more frequent involvement of sciatic and radial nerve seems to be related to their anatomic location and also the position of victims when earthquake happened and the involvement of brachial and lumbosacral plexus could be due to inappropriate evacuation of the victims from the loads and also due to incorrect transportation.

Evaluation of availability, accessibility and prescribing pattern of medicines in the Islamic Republic of Iran

Prescribing, dispensing, availability and affordability of drugs were evaluated in 100 primary health care centres in 5 provinces of the Islamic Republic of Iran using WHO indicators. On average, 92% of the 12 essential drugs monitored were available in the health centre pharmacies and 95% of the drugs prescribed by the physician were dispensed by the health centre pharmacy. The stock-out duration was less than 1 month on average. A complete treatment for pneumonia cost only 2% of the lowest weekly government salary. The national average number of drugs per prescription was 3.4. Prescription of antibiotics and injectable drugs was very high [58% and 41% respectively]. Although availability and affordability of essential drugs is good in this country, rational use of drugs needs to be emphasized

Evaluation of availability, accessibility and prescribing pattern of medicines in the Islamic Republic of Iran

Prescribing, dispensing, availability and affordability of drugs were evaluated in 100 primary health care centres in 5 provinces of the Islamic Republic of Iran using WHO indicators. On average, 92% of the 12 essential drugs monitored were available in the health centre pharmacies and 95% of the drugs prescribed by the physician were dispensed by the health centre pharmacy. The stock-out duration was less than 1 month on average. A complete treatment for pneumonia cost only 2% of the lowest weekly government salary. The national average number of drugs per prescription was 3.4. Prescription of antibiotics and injectable drugs was very high (58% and 41% respectively). Although availability and affordability of essential drugs is good in this country, rational use of drugs needs to be emphasized.

UCP1: the only protein able to mediate adaptive non-shivering thermogenesis and metabolic inefficiency

The uniqueness of UCP1 (as compared to UCP2/UCP3) is evident from expression analysis and ablation studies. UCP1 expression is positively correlated with metabolic inefficiency, being increased by cold acclimation (in adults or perinatally) and overfeeding, and reduced in fasting and genetic obesity. Such a simple relationship is not observable for UCP2/UCP3. Studies with UCP1-ablated animals substantiate the unique role of UCP1: the phenomenon of adaptive adrenergic non-shivering thermogenesis in the intact animal is fully dependent on the presence of UCP1, and so is any kind of cold acclimation-recruited non-shivering thermogenesis; thus UCP2/UCP3 (or any other proteins or metabolic processes) cannot substitute for UCP1 physiologically, irrespective of their demonstrated ability to show uncoupling in reconstituted systems or when ectopically expressed. Norepinephrine-induced thermogenesis in brown-fat cells is absolutely dependent on UCP1, as is the uncoupled state and the recoupling by purine nucleotides in isolated brown-fat mitochondria. Although very high UCP2/UCP3 mRNA levels are observed in brown adipose tissue of UCP1-ablated mice, there is no indication that the isolated brown-fat mitochondria are uncoupled; thus, high expression of UCP2/UCP3 does not necessarily confer to the mitochondria of a tissue a propensity for being innately uncoupled. Whereas the thermogenic effect of fatty acids in brown-fat cells is fully UCP1-dependent, this is not the case in brown-fat mitochondria; this adds complexity to the issues concerning the mechanisms of UCP1 function and the pathway from beta(3)-adrenoceptor stimulation to UCP1 activation and thermogenesis. In addition to amino acid sequences conserved in all UCPs as part of the tripartite structure, all UCPs contain certain residues associated with nucleotide binding. However, conserved amongst all UCP1s so far sequenced, and without parallel in all UCP2/UCP3, are two sequences: 144SHLHGIKP and the C-terminal sequence RQTVDC(A/T)T; these sequences may therefore be essential for the unique thermogenic function of UCP1. The level of UCP1 in the organism is basically regulated at the transcriptional level (physiologically probably mainly through the beta(3)-adrenoceptor/CREB pathway), with influences from UCP1 mRNA stability and from the delay caused by translation. It is concluded that UCP1 is unique amongst the uncoupling proteins and is the only protein able to mediate adaptive non-shivering thermogenesis and the ensuing metabolic inefficiency.

Role of a new mammalian gene family in the biosynthesis of very long chain fatty acids and sphingolipids

Whereas the physiological significance of microsomal fatty acid elongation is generally appreciated, its molecular nature is poorly understood. Here, we describe tissue-specific regulation of a novel mouse gene family encoding components implicated in the synthesis of very long chain fatty acids. The Ssc1 gene appears to be ubiquitously expressed, whereas Ssc2 and Cig30 show a restricted expression pattern. Their translation products are all integral membrane proteins with five putative transmembrane domains. By complementing the homologous yeast mutants, we found that Ssc1 could rescue normal sphingolipid synthesis in the sur4/elo3 mutant lacking the ability to synthesize cerotic acid (C(26:0)). Similarly, Cig30 reverted the phenotype of the fen1/elo2 mutant that has reduced levels of fatty acids in the C(20)-C(24) range. Further, we show that Ssc1 mRNA levels were markedly decreased in the brains of myelin-deficient mouse mutants known to have very low fatty acid chain elongation activity. Conversely, the dramatic induction of Cig30 expression during brown fat recruitment coincided with elevated elongation activity. Our results strongly implicate this new mammalian gene family in tissue-specific synthesis of very long chain fatty acids and sphingolipids.

Cig30 and Pitx3 genes are arranged in a partially overlapping tail-to-tail array resulting in complementary transcripts

The mouse Cig30 gene codes for a 30-kDa membrane glycoprotein, which appears to have a role in the recruitment of brown adipose tissue. To elucidate the structure of the Cig30 gene, we have isolated a lambda phage genomic DNA clone containing the entire mouse gene and found that Cig30 consists of four exons that are spread over 4 kilobase pairs of genomic sequence. Using a fluorescence in situ hybridization assay and interspecific backcross panel mapping, we have localized the Cig30 locus to the distal region of mouse chromosome 19, between the Tlx1 and Ins1 loci. Sequencing of the corresponding lambda clone to completion revealed that the insert contained yet another gene in the opposite orientation. It turned out to be the newly identified homeobox gene Pitx3. Interestingly, the genes are very tightly linked, so that the 3' ends of their transcripts are complementary. Thus, our results provide evidence for bidirectional transcription of a several hundred base pair-long DNA region as a result of the extremely tight linkage between Cig30 and Pitx3.

Cig30, a mouse member of a novel membrane protein gene family, is involved in the recruitment of brown adipose tissue

We have identified a previously uncharacterized gene that is implicated in the thermogenic function of brown adipose tissue of mice. This gene, termed Cig30, is the first mammalian member of a novel gene family comprising several nematode and yeast genes, such as SUR4 and FEN1, mutation of which is associated with highly pleiotropic phenotypes. It codes for a 30-kDa plasma membrane glycoprotein with five putative transmembrane domains. The Cig30 mRNA was readily detected only in brown fat and liver. When animals were exposed to a 3-day cold stress, the Cig30 expression was selectively elevated in brown fat more than 200-fold. Similar increases were brought about in two other conditions of brown fat recruitment, namely during perinatal development and after cafeteria diet. The magnitude of Cig30 mRNA induction in the cold could be mimicked by chronic norepinephrine treatment in vivo. However, in primary cultures of brown adipocytes, a synergistic action of norepinephrine and dexamethasone was required for full expression of the gene, indicating that both catecholamines and glucocorticoids are required for the induction of Cig30. We propose that the CIG30 protein is involved in a pathway connected with brown fat hyperplasia.