245 research outputs found

    Tissue- and Stage-specific Expression of Two Lipophorin Receptor Variants with Seven and Eight Ligand-binding Repeats in the Adult Mosquito

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    We identified two splice variants of lipophorin receptor (LpR) gene products specific to the mosquito fat body (AaLpRfb) and ovary (AaLpRov) with respective molecular masses of 99.3 and 128.9 kDa. Each LpR variant encodes a member of the low density lipoprotein receptor family with five characteristic domains: 1) ligand recognition, 2) epidermal growth factor precursor, 3) putative O-linked sugar, 4) single membrane-spanning domains, and 5) the cytoplasmic tail with a highly conserved internalization signal FDNPVY. Proposed phylogenetic relationships among low density lipoprotein receptor superfamily members suggest that the LpRs of insects are more closely related to vertebrate low density lipoprotein receptors and very low density lipoprotein receptor/vitellogenin receptor than to insect vitellogenin receptor/yolk protein receptors. Two mosquito LpR isoforms differ in their amino termini, the ligand-binding domains, and O-linked sugar domains, which are generated by differential splicing. Polymerase chain reaction and Southern blot hybridization analyses show that these two transcripts originated from a single gene. Significantly, the putative ligand-binding domain consists of seven and eight complement-type, cysteine-rich repeats inAaLpRfb and AaLRov, respectively. Seven cysteine-rich repeats in AaLpRfb are identical to the second through eighth repeats of AaLpRov. Previous analyses (1) have indicated that the AaLpRov transcript is present exclusively in ovarian germ-line cells, nurse cells, and oocytes throughout the previtellogenic and vitellogenic stages, with the peak at 24–30 h after blood meal, coincident with the peak of yolk protein uptake. In contrast, the fat body-specific AaLpRfb transcript expression is restricted to the postvitellogenic period, during which yolk protein production is terminated and the fat body is transformed to a storage depot of lipid, carbohydrate, and protein

    An improved baculovirus insecticide producing occlusion bodies that contain Bacillus thuringiensis insect toxin

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    Baculovirus occlusion bodies, large proteinaceous structures which contain virions, have recently been engineered to incorporate foreign proteins. The major constituent protein of occlusion bodies from the baculovirus Autographa californica nucleopolyhedrovirus is polyhedrin, and assembly of recombinant occlusion bodies which incorporate a foreign protein depends on an interaction between native polyhedrin and a polyhedrin–foreign protein fusion. This technology has now been applied to the generation of a recombinant baculovirus (ColorBtrus) that produces occlusion bodies incorporating the Bacillus thuringiensis (Bt) insecticidal Cry1Ac toxin protein. ColorBtrus coexpresses native polyhedrin and a fusion protein in which polyhedrin is fused to the Bt toxin, which is in turn fused to green fluorescent protein (GFP). Analysis of ColorBtrus occlusion bodies confirmed that they include both Bt toxin and GFP, yet still incorporate virions. Bioassay of ColorBtrus demonstrated that its speed of action and pathogenicity are strikingly enhanced compared to wild-type virus. ColorBtrus represents a novel, powerful biological insecticide that combines positive attributes of both Bt toxin and baculovirus based systems

    Utility of end-tidal carbon dioxide monitoring in intramuscular ketamine sedation in the pediatric emergency department

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    Purpose Recently, the use of end-tidal carbon dioxide (ETCO2) monitoring has been suggested for early detection of hypoventilation over oxygen saturation (SPO2) monitoring. We aimed to determine the usefulness of capnography in monitoring patients sedated using intramuscular (IM) ketamine in the pediatric emergency department (ED). Methods This study retrospectively reviewed medical records of patients younger than 16 years who were sedated using IM ketamine and whose ETCO2 values were documented in the ED. Age, sex, American Society of Anesthesiologists physical status classification (ASA classification), and purpose of sedation were investigated. Vital signs were recorded at pre-sedation, 5 and 10 minutes after sedation, and after recovery. Hypoventilation was defined as S P O2 < 95%, ETCO2 ≄ 50 mmHg or ≀30 mmHg, or increase in ETCO2 ≄ 10 mmHg from the baseline without tachypnea. Results A total of 49 patients were investigated; 42 of them belonged to ASA classification I, and 7 to II. There was no patient with SPO2 < 95%, or ETCO2 ≄ 50 mmHg, or increase in ETCO2 ≄ 10 mmHg from the pre-sedation value. However, 5 patients had an ETCO2 ≀ 30 mmHg, and 4 of them (8.2%) had normal respiratory rate and were suitable for hypopneic hypoventilation. Ten patients showed abnormal range of ETCO2 (normal range, 35–45 mmHg), but did not meet the definition of hypoventilation. No one had clinically serious respiratory events. Conclusion During sedation using IM ketamine, 8.2% of the patients had hypopneic hypoventilation without hypoxemia, and they were all younger than 36 months. Capnography for patients sedated using IM ketamine in the ED is useful in detecting hypopneic hypoventilation, and has the potential for preventing clinically serious respiratory events in patients, especially toddlers

    A Case of Nephrogenic Diabetes Insipidus with a Rare X-linked Recessive Mutation in an Infant with Developmental and Growth Retardation Tracked by the Korean National Health Screening Program

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    Nephrogenic diabetes insipidus (DI) is a rare disease in which the patient cannot concentrate urine despite appropriate or high secretion of antidiuretic hormone. Congenital nephrogenic DI is caused by the arginine vasopressin receptor 2 (AVPR2) or aquaporin 2 (AQP2) gene mutation; the AVPR2 genetic mutation accounts for 90% of the cases. National health screening for infants and children was launched in 2007 in order to prevent accidents and promote public health in infants and children in Korea. The program has been widely used as a primary clinical service in Korea. We treated an infant with faltering growth and delayed development detected by the National health screening program, and diagnosed the problem as nephrogenic DI caused by a rare missense mutation of c.490T>C on the AVPR2 gene. This case can be a good educational nephrogenic DI with a rare AVPR2 mutation, which was well screened and traced by the national health screening program for infants and children in Korea

    Genotype and Phenotype Spectrum of FRMD7-Associated Infantile Nystagmus Syndrome

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    PURPOSE. We investigate the genotype and phenotype spectrum of FRMD7-associated infantile nystagmus syndrome in Korean probands. METHODS. A total of 37 patients with infantile nystagmus syndrome were recruited prospectively for genetic analysis. We performed polymerase chain reaction (PCR)-based direct sequencing and haplotype analysis for FRMD7. Detailed ophthalmic examinations and eye movement recordings were compared between FRMD7 and non-FRMD7 groups. RESULTS. In 13 (35%) of 37 patients, five different mutations of FRMD7 were detected: start codon mutation c.1A&gt;G, splice site mutation c.162thorn6T&gt;C, and three missense mutations (c.575A&gt;C, c.722A&gt;G, and c.875T&gt;C). The latter mutation was identified in seven unrelated patients, and always was accompanied with two single nucleotide polymorphisms of exon 12 (rs6637934, rs5977623). Compared to non-FRMD7 groups, a cup-to-disc ratio was significantly decreased in FRMD7 groups (P &lt; 0.001), and a disc-macula distance to disc diameter ratio markedly increased in the FRMD7 group (P = 0.015). Most patients in the FRMD7 group had at least two types of the nystagmus waveforms, and the most common type was unidirectional jerk nystagmus (75%), such as pure jerk and jerk with extended foveation, followed by pendular (25%), bidirectional jerk (19%), and dual jerk (6%) nystagmus. No significant differences were observed between FRMD7 and non-FRMD7 groups in terms of the nystagmus waveform, presence of periodic alternating nystagmus, and mean foveation time. CONCLUSIONS. We identified five FRMD7 mutations in 35% of our infantile nystagmus syndrome cohort, expanding its mutational spectrum. The missense mutation c.875T&gt;C may be a common mutation arisen from the founder effect in Korea. Optic nerve dysplasia associated with FRMD7 mutations suggests that the abnormal development of afferent visual systems may affect neural circuitry within the oculomotor syste

    Signal change in hippocampus and current source of spikes in Panayiotopoulos syndrome

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    A 4-year-old girl with Panayiotopoulos syndrome presented with a history of 4 prolonged autonomic seizures. The clinical features of her seizures included, in order of occurrence, blank staring, pallor, vomiting, hemi-clonic movement on the right side, and unresponsiveness. A brain magnetic resonance imaging (MRI) showed a slightly high T2 signal in the left hippocampus. Interictal electoencephalogram revealed spikes in the occipital area of the left hemisphere. We analyzed the current-source distribution of the spikes to examine the relationship between the current source and the high T2 signal. The current source of the occipital spikes was not only distributed in the occipital area of both cerebral hemispheres, but also extended to the posterior temporal area of the left hemisphere. These findings suggest that the left temporal lobe may be one of the hyperexcitable areas and form part of the epileptogenic area in this patient. We hypothesized that the high T2 signal in the left hippocampus of our patient may not have been an incidental lesion, but instead may be related to the underlying electroclinical diagnosis of Panayiotopoulos syndrome, and particularly seizure. This notion is important because an abnormal T2 signal in the hippocampus may represent an acute stage of hippocampal injury, although there is no previous report of hippocampal pathology in Panayiotopoulos syndrome. Therefore, long-term observation and serial follow-up MRIs may be needed to confirm the clinical significance of the T2 signal change in the hippocampus of this patient
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