Current Status of Neurosurgical and Neurointensive Care Units in Korea : A Brief Report on Nationwide Survey Results.

OBJECTIVE: The purpose of this study is identify the operation status of the neurosurgical care units (NCUs) in neurosurgical residency training hospitals nationwide and determine needed changes by comparing findings with those obtained from the Korean Neurosurgical Society (KNS) and Korean Society of Neurointensive Care Medicine (KNIC) survey of 2010. METHOD: This survey was conducted over 1 year in 86 neurosurgical residency training hospitals and two neurosurgery specialist hospitals and focused on the following areas : 1) the current status of the infrastructure and operating systems of NCUs in Korea, 2) barriers to installing neurointensivist team systems, 3) future roles of the KNS and KNIC, and 4) a handbook for physicians and practitioners in NCUs. We compared and analyzed the results of this survey with those from a KNIC survey of 2010. RESULTS: Seventy seven hospitals (87.5%) participated in the survey. Nineteen hospitals (24.7%) employed a neurointensivist or faculty member; Thirty seven hospitals (48.1%) reported high demand for neurointensivists, and 62 hospitals (80.5%) stated that the mandatory deployment of a neurointensivist improved the quality of patient care. Forty four hospitals (57.1%) believed that hiring neurointensivist would increase hospital costs, and in response to a question on potential earnings declines. In terms of potential solutions to these problems, 70 respondents (90.9%) maintained that additional fees were necessary for neurointensivists' work, and 64 (83.1%) answered that direct support was needed of the personnel expenses for neurointensivists. CONCLUSION: We hope the results of this survey will guide successful implementation of neurointensivist systems across Korea.

Role of tropomyosin in silkworm allergy.

Silkworm pupae are widely consumed in Asian countries and allergic reactions following consumption have been described. However, false­positive responses in skin prick allergy tests or non­specific immunoglobulin E (IgE) responses to total extract of silkworm pupa make diagnosis difficult. Although improved allergy diagnosis is required, molecular characterization of silkworm allergens has not been performed to date, except for Bomb m 1, an arginine kinase. This study aimed to evaluate the allergenicity of tropomyosin, a well­established invertebrate pan­allergen, from silkworm pupa. The silkworm tropomyosin gene was cloned by reverse transcription and polymerase chain reaction, and the protein was overexpressed in Escherichia coli and purified by affinity chromatography using Nickel­resin. IgE reactivity of the recombinant protein was examined by ELISA and competitive inhibition analyses. Silkworm pupa tropomyosin shared 73.5­92.3% amino acid sequence identity with previously identified allergenic tropomyosins. Sera from eight of 15 patients with silkworm allergy (53.3%) exhibited binding of IgE to the recombinant protein. However, recombinant protein was able to inhibit less than 10% of IgE reactivity to silkworm pupa extract. Of the eight sera tested, six that specifically reacted with silkworm tropomyosin also demonstrated IgE reactivity to shrimp and crab. In the present study, specific IgE to silkworm tropomyosin was detected in patients with silkworm allergy, suggesting that it may be useful in diagnosis of allergy to silkworm pupa.

The effects of storage conditions on the stability of house dust mite extracts.

PURPOSE: Allergen extracts from the house dust mite (HDM, Dermatophagoides pteronyssinus) are widely utilized for diagnosis and treatment of allergic diseases. It is known that allergen extracts degrade and lose potency when stored over time. METHODS: This study aimed to determine the optimal conditions for stability of allergen extracts. This study was undertaken to investigate the optimal storage conditions for HDM extracts, the effects of adding 0.03% human serum albumin (HSA) and 50% glycerol were evaluated at -20℃, 4℃, and room temperature (RT). Changes in protein and group 1 major allergen (Der p 1) concentration, as well as allergenicity were measured over a 1 year period using the Bradford assay, two-site ELISA, and ELISA inhibition. RESULTS: Protein concentrations decreased by 86%, 51%, and 6% at RT, 4℃, and -20℃, respectively, when stored in distilled water. Overall allergenicity remained high (89.9%) when the extracts was reconstituted in 50% glycerol solution, and was 93.1% when reconstituted in 50% glycerol and 0.03% HSA at RT. Allergenicity was decreased to 36.6% and 33.3%, however, reconstitution in DW or 0.03% HSA solution at RT, respectively. Allergenicity was remained high as 92.0%-97.0% when stored at 4℃ regardless of the buffer conditions. CONCLUSIONS: Storage temperature is the most important factor in preserving allergenicity of HDM extracts, which is ideal at 4℃. The addition of 50% glycerol to the storage buffer was also found to play an important role in increasing the shelf-life of HDM extracts at RT.

Identification of novel allergenic components from German cockroach fecal extract by a proteomic approach.

BACKGROUND: Cockroaches produce potent allergens, and cockroach feces are known to be especially rich in allergens. In this study, we analyze the allergenic components from cockroach feces and evaluate allergenicity of recombinant α-amylase identified from fecal extract. METHODS: IgE-reactive proteins from German cockroach fecal extract were analyzed by proteomic analysis and immunoblotting. Recombinant α-amylase was produced and its allergenicity was evaluated by ELISA. RESULTS: Analysis of German cockroach fecal extracts identified 12 IgE-reactive components. Most of these allergens were found to be digestive enzymes such as α-amylase, trypsin, chymotrypsin, metalloprotease, and midgut carboxypeptidase A, but the identity of 3 IgE-reactive proteins is still unknown. Glycinin-like proteins, which were likely derived from the cockroach diet, were also identified. German cockroach α-amylase shares the highest identity with pig α-amylase (55.8%), followed by mite group 4 allergens (Blo t 4, 50.4%; Der p 4, 49.8%; Eur m 4, 47.4%). In this study, recombinant α-amylase from German cockroach was expressed, and its allergenicity was examined by ELISA. Specific IgE against recombinant amylase was detected in 41.4% (12/29) of serum samples from German cockroach-sensitized subjects. Recombinant α-amylase was able to inhibit 55% of specific IgE to German cockroach whole-body extract. CONCLUSIONS: Amylase was found to be an important novel allergen in cockroach feces. It is hoped that recombinant α-amylase will be useful for further studies and clinical applications.

Functional and molecular identification of pH-sensitive K+ channels in murine urinary bladder smooth muscle.

OBJECTIVE: To examine the role of pH-sensitive K(+) channels in setting the resting membrane potential in murine bladder smooth muscle, as bladder contractility is influenced by the resting membrane potential, which is mainly regulated by background K(+) conductances. MATERIALS AND METHODS: Using conventional microelectrode recordings, isometric tension measurements, patch-clamp recordings, reverse transcription-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry, we assessed bladder smooth muscle cells and tissues. RESULTS: Acidic pH (pH 6.5) depolarized the resting membrane potential of murine bladder smooth muscles and increased muscle tone and contractility. The pH-induced changes were not abolished by neuronal blockers or classical K(+)-channel antagonists. Lidocaine (1 mM) and bupivacaine (100 microm) mimicked the effects of acidifying the external solution, and in the presence of lidocaine no further increase in contractility was induced by reducing the pH to 6.5. Voltage-clamp experiments on freshly dispersed bladder myocytes showed that pH 6.5 decreased the outward current. Pre-treatment of bladder myocytes with the classical K(+) antagonists tetraethylammonium (10 mm), 4-aminopyridine (5 mM), glibenclamide (10 microm) or apamin (300 nM) did not inhibit the effects of low pH on outward current. However, treatment with lidocaine (1 mM) abolished the effects of acidic pH on outward current. RT-PCR showed the expression of the acid-sensitive K(+) channel (TASK)-1 and TASK-2 gene transcripts in murine bladder, and immunohistochemistry and Western blot analysis showed TASK-1 and TASK-2 channel expression and distribution in smooth muscle tissues and cells. CONCLUSION: TASK channels are expressed in bladder smooth muscle and contribute to the basal K(+) conductances responsible for resting membrane potential.

Disruption of protein-protein interaction in the Mgl-1 oncoprotein.

Mammalian homologues of the Lethal giant larvae (Lgl) tumor suppressor gene have been identified and these homologues can complement the yeast double mutant of Sop1 and Sop2, the yeast homologue of Lgl, as reported previously. In the absence of these genes in yeast, cellular viability is affected at restrictive temperature and salt environments. Members of this family contain five or more of the WD-40 repeat motifs, which is known to be involved in protein-protein interaction. In order to investigate the biochemical roles for conserved amino acids within the most conserved WD-40 repeat motif amongst these family members, we generated deletion mutants for five conserved amino acids (G450, H451, D453, W459 and D460) in mouse Lgl-1 (Mgl-1), located between 450-460 amino acids. We found that the deletion mutants of Mgl-1, DeltaG450 and DeltaD453, were not capable of complementing yeast mutants of Sop1 and Sop2 at restrictive temperature and high salt environments. These results indicate that the WD-40 repeat motif is important for cellular viability by regulating temperature-sensitivity and salt tolerance in yeast.

A pH-sensitive potassium conductance (TASK) and its function in the murine gastrointestinal tract.

The excitability of smooth muscles is regulated, in part, by background K+ conductances that determine resting membrane potential. However, the K+ conductances so far described in gastrointestinal (GI) muscles are not sufficient to explain the negative resting potentials of these cells. Here we describe expression of two-pore K+ channels of the TASK family in murine small and large intestinal muscles. TASK-2, cloned from murine intestinal muscles, resulted in a pH-sensitive, time-dependent, non-inactivating K+ conductance with slow activation kinetics. A similar conductance was found in native intestinal myocytes using whole-cell patch-clamp conditions. The pH-sensitive current was blocked by local anaesthetics. Lidocaine, bupivacaine and acidic pH depolarized circular muscle cells in intact muscles and decreased amplitude and frequency of slow waves. The effects of lidocaine were not blocked by tetraethylammonium chloride, 4-aminopyridine, glibenclamide, apamin or MK-499. However, depolarization by acidic pH was abolished by pre-treatment with lidocaine, suggesting that lidocaine-sensitive K+ channels were responsible for pH-sensitive changes in membrane potential. The kinetics of activation, sensitivity to pH, and pharmacology of the conductance in intestinal myocytes and the expression of TASK-1 and TASK-2 in these cells suggest that the pH-sensitive background conductance is encoded by TASK genes. This conductance appears to contribute significantly to resting potential and may regulate excitability of GI muscles.