Differential effects of neurotrophins on ocular dominance plasticity in developing and adult cat visual cortex

In the present study we examine the influence of neurotrophins on experience-dependent synaptic rearrangement in developing and adult visual cortex. Brain-derived neurotrophic factor (BDNF) or nerve growth factor (NGF) was continuously infused into cortical area 18, and the functional architecture of the cortex was examined by use of optical and electrophysiological recording techniques. In kittens, BDNF infusion during monocular deprivation (MD) reversed the normally occurring ocular dominance (OD) shift towards the non-deprived eye so that the deprived eye dominated the BDNF-treated cortex after MD. Under conditions of equal activation of thalamocortical synapses, i.e. when animals were either subject to binocular deprivation (BD) or reared without deprivation, BDNF infusion did not disrupt binocularity of cortical units, but reversed the natural OD bias towards the contralateral eye in favour of the ipsilateral eye. In addition, BDNF treatment in kittens led to a loss of the orientation selectivity of cortical units irrespective of rearing conditions. In adult animals, BDNF influenced neither OD distributions nor orientation selectivity. The effect of NGF was markedly different. It was ineffective in kittens but in adult animals it caused a shift of OD towards the deprived eye when MD was combined with NGF infusion. However, in this case orientation selectivity was preserved. Thus, both neurotrophins have profound activity- and age-dependent effects on the functional architecture of the visual cortex. Moreover, our results indicate that simple substitution of neurotrophins in excess is unlikely to compensate for deprivation effects by preserving or restoring the normal functional architecture of the cortex.

Characterization and cDNA cloning of a platelet aggregation inhibitor

A novel platelet aggregation inhibitor, sal-C, was purified to homogeneity from the venom of Korean snake (Agkistrodon halys brevicaudus). Several lines of experimental evidence clearly indicated that sal-C inhibits not only the collagen-induced platelet aggregation, but also the aggregation mediated by the cell surface glycoprotein IIb-IIIa (GP IIb-IIIa). We have isolated the cDNA encoding sal-C from the cDNA library of the snake venom gland and analyzed its complete nucleotide sequence. Sal-C is a single-chain polypeptide composed of 212 amino acids including 24 cysteines. The deduced polypeptide sequence of sal-C demonstrated considerable homology to previously described protein species of the collagen-induced platelet aggregation inhibitor family. Sal-C does not have the Arg-Gly-Asp (RGD) motif, but contains the Ser-Glu-Cys-Asp sequence. Interestingly, sal-C was found to inhibit GP IIb-IIIa binding to immobilized fibrinogen which is antagonized by the typical RGD motif of disintegrins.

Suppressive mechanism of salmosin, a novel disintegrin in B16 melanoma cell metastasis

We have previously reported that salmosin, a novel disintegrin, was isolated from Korean snake (Agkistrodon halys brevicaudus) venom and significantly inhibited solid tumor growth in mice by perturbation of tumor-specific angiogenesis via blocking alphavbeta3 integrin expressed on vascular endothelial cells. In this study, we investigated the functional specificity of salmosin in tumor cell metastasis. Recombinant salmosin expressed in E. coli that has the RGD sequence markedly inhibited both B16F10 melanoma cell adhesion to the extracellular matrix proteins as well as B16F10 melanoma cell invasion through Matrigel-coated filter. The inhibition by salmosin can be caused by blocking integrins expressed on the surface of B16F10 melanoma cells. Salmosin significantly inhibited the proliferation of B16F10 melanoma cells on the plate coated with collagen I in a dose-dependent manner. In vivo B16F10 melanoma experimental metastasis, salmosin showed remarkable significant inhibitory effect on lung tumor colonization in a concentration-dependent manner. These results clearly demonstrate that antimetastatic activity of salmosin resulted from blocking the integrin-mediated adherence and alphavbeta3 integrin-mediated proliferation of the melanoma cells.

Pneumocystis carinii pneumonia associated with a rapid reduction of cortisol level in a patient with ectopic ACTH syndrome treated by octreotide and ketoconazole

A case is herein reported of pneumocystis carinii pneumonia in a 60-year-old female patient with ectopic production of ACTH at a position 2 cm superior to her right clavicle, revealed in an octreotide scan. Her extremely high plasma ACTH and cortisol levels (460 pg/ml and 80 microg/dl, respectively) were markedly decreased with the combined treatment of octreotide (300 microg/d) and ketoconazole (600 mg/d). As her serum cortisol concentration decreased, pneumocystis carinii pneumonia occurred on the third day of treatment. A secondary E. coli infection was superimposed and the patient died of disseminated intravascular coagulation and adult respiratory distress syndrome. This case suggests that primary prophylaxis for pneumocystis carinii infection should be initiated before cortisol lowering therapy, especially when the plasma cortisol concentration is excessively high, and that early adjunctive glucocorticoid therapy can reduce the acute mortality in patients with endogenous Cushing's syndrome and Pneumocystis carinii pneumonia. This case study would also like to point out that plasma ACTH and cortisol levels were decreased effectively by the combination of octreotide and ketoconazole in this instance of ectopic ACTH syndrome.

Spatiotemporal dynamics of the BOLD fMRI signals: toward mapping submillimeter cortical columns using the early negative response

The existence of the early-negative blood-oxygenation-level-dependent (BOLD) response is controversial and its practical utility for mapping brain functions with columnar spatial specificity remains questionable. To address these issues, gradient-echo BOLD fMRI studies were performed at 4.7 T and 9.4 T using the well-established orientation column model in the cat visual cortex. A robust transient early-negative BOLD response was consistently observed in anesthetized cat (-0.35 +/- 0.09%, mean +/- SD, n = 8 at 2.9 +/- 0.5 sec poststimulus onset for 4.7 T, TE = 31 ms; -0.29 +/- 0.10%, n = 4 at 3.0 +/- 0.8 sec poststimulus onset for 9.4 T, TE = 12 ms). In addition to its temporal evolution, the BOLD response also evolved dynamically in the spatial domain. The initially spatially localized early-negative signal appeared to dynamically drain from the active sites toward large vessels, followed by a wave of the delayed positive signal, which exhibited similar spatiotemporal dynamics. Only the early-negative BOLD response within 2 sec of the stimulus onset (not the entire dip) yielded columnar layouts without differential subtraction. The functional maps of two orthogonal orientations using the first 2-sec dip were indeed complementary. On the other hand, the delayed positive BOLD response appeared diffused and extended beyond the active sites. It was thus less suitable to resolve columnar layouts. These results have implications for the design and interpretation of the BOLD fMRI at columnar resolution. Magn Reson Med 44:231-242, 2000.

Biomass evolution in porous media and its effects on permeability under starvation conditions

The purpose of this study was to understand bacteria profile modification and its applications in subsurface biological operations such as biobarrier formation, in situ bioremediation, and microbial-enhanced oil recovery. Biomass accumulation and evolution in porous media were investigated both experimentally and theoretically. To study both nutrient-rich and carbon-source-depleted conditions, Leuconostoc mesenteroides was chosen because of its rapid growth rate and exopolymer production rate. Porous micromodels were used to study the effects of biomass evolution on the permeability of a porous medium. Bacterial starvation was initiated by switching the feed from a nutrient solution to a buffer solution in order to examine biofilm stability under nutrient-poor conditions. Four different evolution patterns were identified during the nutrient-rich and nutrient-depleted conditions used in the micromodel experiments. In phase I, the permeability of the porous micromodel decreased as a result of biomass accumulation in pore bodies and pore throats. In phase II, starvation conditions were initiated. The depletion of nutrient in the phase II resulted in slower growth of the biofilm causing the permeability to reach a minimum as all the remaining nutrients were consumed. In phase III, permeability began to increase due to biofilm sloughing caused by shear stress. In phase IV, shear stress remained below the critical shear stress for sloughing and the biofilm remained stable for long periods of time during starvation. The critical shear stress for biofilm sloughing provided an indication of biofilm strength. Shear removal of biofilms occurred when shear stress exceeded critical shear stress. A network model was used to describe the biofilm formation phenomenon and the existence of a critical shear stress. Simulations were in qualitative agreement with the experimental results, and demonstrate the existence of a critical shear stress.

Dopamine-deficient mice are hypersensitive to dopamine receptor agonists

Dopamine-deficient (DA-/-) mice were created by targeted inactivation of the tyrosine hydroxylase gene in dopaminergic neurons. The locomotor activity response of these mutants to dopamine D1 or D2 receptor agonists and l-3,4-dihydroxyphenylalanine (l-DOPA) was 3- to 13-fold greater than the response elicited from wild-type mice. The enhanced sensitivity of DA-/- mice to agonists was independent of changes in steady-state levels of dopamine receptors and the presynaptic dopamine transporter as measured by ligand binding. The acute behavioral response of DA-/- mice to a dopamine D1 receptor agonist was correlated with c-fos induction in the striatum, a brain nucleus that receives dense dopaminergic input. Chronic replacement of dopamine to DA-/- mice by repeated l-DOPA administration over 4 d relieved the hypersensitivity of DA-/- mutants in terms of induction of both locomotion and striatal c-fos expression. The results suggest that the chronic presence of dopaminergic neurotransmission is required to dampen the intracellular signaling response of striatal neurons.

Risk factors for the development of hemodynamically significant cardiac arrhythmias in patients with mechanical ventilation

PURPOSE

The purpose of this article was to identify the risk factors related to development of hemodynamically significant cardiac arrhythmias in patients with mechanical ventilation.

MATERIALS AND METHODS

Holter recording and echocardiogram were performed within 24 hours of ventilator initiation in patients on mechanical ventilation (MV) owing to respiratory failure (RF) from various reasons.

RESULTS

From 68 patients, hemodynamically significant cardiac arrhythmias were detected in 18 patients (26.5%). Initial mean arterial pressure, maximal heart rate, and initial pH were identified as risk factors for hemodynamically significant cardiac arrhythmias. Additionally, the patients with pressure-controlled ventilation as an initial ventilatory mode developed hemodynamically significant cardiac arrhythmias less frequently than the patients with other modes (15.8% vs. 40%, P = .03). In multivariate analysis, initial mean arterial pressure (< 70 mm Hg, odds ratio [OR]: 5.5; 95% confidence interval [CI]: 1.2 to 24.2, P = .026), maximal heart rate (> 120/min, OR: 19.7; 95% CI: 2.0 to 190.9, P = .01), and pressure-controlled ventilation (OR: 0.13; 95% CI: 0.03 to 0.55, P = .006) were associated with the development of hemodynamically significant cardiac arrhythmias.

CONCLUSIONS

These findings suggest that during the early stages of mechanical ventilation with acute respiratory failure, hemodynamically significant cardiac arrhythmias are directly associated with tachycardia (> or = 120/min), initial MAP (<70 mm Hg), and, inversely, the initial use of pressure-controlled ventilation.

Effect of an additional 1-hour T-piece trial on weaning outcome at minimal pressure support

PURPOSE

The purpose of this article was to investigate the effect of an additional 1-hour T-piece trial at the level of minimum pressure support (PSmin) on weaning outcome.

MATERIALS AND METHODS

Open, randomized, prospective study of 44 patients who had received mechanical ventilation for more than 3 days.Thirty-six patients satisfied the protocol. There were 42 weaning trials. The patients were randomized into an intervention group (additional 1-hour period of T-piece trial) and a control group (extubation directly) at PSmin. Blood gas analysis and estimation of respiratory and hemodynamic variables were performed at the 15 cm H2O level of pressure support. Measurements were repeated at PSmin and during weaning process (in intervention group).

RESULTS

Mean PSmin level was 7.6 (+/- 1.9) cm H2O. There were no differences in total ventilation time (TVT), acute physiology and chronic health evaluation (APACHE) II score, nutritional indices, and respiratory mechanics on PSmin between the two groups. The weaning success rate and the reintubation rate were similar for the intervention group (55% and 18%, respectively) and control group (70% and 20%, respectively). Work of breathing, pressure time product, and tidal volume significantly worsened after a 1-hour T-piece trial when compared with those values measured at PSmin in the intervention group (P < .05). For the combined patient sample, TVT and tidal volume at PSmin were significantly different between the patients with weaning success (246 +/- 195 hours, 0.43 +/- 0.11 L) and those with weaning failure (407 +/- 248 hours, 0.35 +/- 0.10 L) (P < .05 in each).

CONCLUSION

There were no advantages in weaning outcome by the addition of a 1-hour T-piece trial compared with prompt extubation at PSmin.

Serologic and histopathologic study of Chlamydia pneumoniae infection in atherosclerosis: a possible pathogenetic mechanism of atherosclerosis induced by Chlamydia pneumoniae

Chronic infection and inflammation have recently been implicated as important etiologic agents for atherosclerosis in general and, in particular, ischemic heart disease. Several agents have been suggested as possible candidates for the chronic inflammation including cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae. We hypothesized that a vascular infection with C. pneumoniae may induce a chronic inflammatory reaction in the host vascular tissue and activated inflammatory cells may express inflammatory mediators such as cyclooxygenase-2 (COX-2) and matrix metalloproteinases (MMPs). At first, we evaluated the relationship between C. pneumoniae infection and atherosclerosis indirectly by serologic study, and then, to confirm our hypothesis, we performed an immunohistochemical study of atherosclerotic plaques. The seropositive rate of anti-Chlamydia pneumoniae IgG was higher in the disease group (Group I, 59.8%, n = 254) than in the negative control group (Group III, 47.4%, n = 97) (p = 0.041), but the anti-Chlamydia pneumoniae IgA was not different in seropositivity between the two groups (Group I, 64.6%; Group III, 57.7%). The simultaneous seropositive rates of both IgG and IgA were 56.7% in Group I and 43.3% in Group III (p = 0.033). In subgroups without the conventional risk factors of atherosclerosis, these findings were more prominent. Furthermore, we performed immunohistochemical staining on the atherosclerotic aortic tissues obtained from patients that were seropositive to C. pneumoniae (n = 5), by using antibodies to C. pneumoniae, COX-2, and MMP-9. The immunoreactivity for COX-2 and MMP-9 increased in the atherosclerotic plaques itself, predominantly in the surrounding area of immunoreactive C. pneumoniae. These findings support our hypothesis and C. pneumoniae may participate in a pathogenetic mechanism for atherogenesis or progression of atherosclerosis. The present study may open a promising perspective concerning future therapeutic trials of chronic inflammation related atherogenesis under pathophysiological conditions.

Effects of oncostatin M on hormone release of rat pituitary cells in primary culture

It has become increasingly clear that cytokines play an important role in modulating neuroendocrine regulation, especially in the secretion of corticotropin (ACTH) in the pituitary. Oncostatin M (OSM), a cytokine of IL-6 family has been reported to increase ACTH secretion and pro-opiomelanocortin (POMC) transcription in murine corticotroph pituitary tumor cells (AtT20 cells). The present study was undertaken to determine the effects of OSM on hormonal release in primary culture of rat pituitary cells. Growth hormone or prolactin release was not affected by OSM. OSM (1 nM) stimulated ACTH release (35.1% increase versus control, p<0.001) in dispersed pituitary cells of rat to a lesser extent than in AtT20 cells. Corticotropin releasing hormone (CRH) (10 nM) also induced a 2.3-fold increase of ACTH secretion (p<0.001), but co-treatment of OSM and CRH did not exhibit any synergistic effect on ACTH secretion. We conclude OSM has a stimulatory effect on ACTH secretion in normal rat pituitary cell cultures, and OSM acts mainly on corticotroph, supporting the potential role of OSM to modulate immune-endocrine regulation in the pituitary.

Closing volume influences the postural effect on oxygenation in unilateral lung disease

In normal adults, both blood flow and ventilation are distributed preferentially to the dependent lung zones. In adults with unilateral lung disease, arterial oxygenation improves when they are positioned with their good lung down because of improved matching of ventilation and perfusion. When the closing volume is increased, dependent airways are closed during tidal breathing, so that reduced ventilation-perfusion ratio and hypoxia develops and ventilation is preferentially distributed to the upper lung zones. We undertook an observational study on the effects of lateral recumbency on arterial oxygenation in adult patients with unilateral lung disease and tested the hypothesis that oxygenation in lateral recumbency might be influenced by an increase in closing volume. Arterial blood gases were analyzed in the supine, right and left lateral decubitus positions and the AaPO(2) was calculated in 44 randomly selected patients 49.9 +/- 18.7 yr of age with unilateral pneumonia (23 cases) or pulmonary tuberculosis (21 cases). In 26 patients, individual Pa(O(2)) with the normal lung in the dependent position was higher than that with the diseased lung; the opposite was true for 18 patients. The difference in Pa(O(2)) and AaPO(2) between the two positions was statistically significant in both groups. In 16 patients (10 men and six women 49.2 +/- 18.2 yr of age), we measured closing volume and determined the fractional ventilation to each lung by (133)Xe lung scan in the three positions. In these 16 patients, the difference in Pa(O(2)) between the normal and the diseased lung in the dependent position was related significantly to the difference in the fractional ventilation going to the normal lung between the dependent and the supine position (r = 0.642, p = 0. 007). The latter was related significantly to the % predicted closing volume (CV/VC) (r = -0.597, p = 0.015). This study has shown that closing volume, as well as posture, might be involved in determining oxygenation in lateral recumbency in patients with unilateral lung disease.

Arrangement of orientation pinwheel centers around area 17/18 transition zone in cat visual cortex

In the primary visual cortex of higher mammals, orientation preferences are represented continuously except for singular points, so-called pinwheel centers. In spite of the uniqueness of orientation pinwheel centers, very little is known about the pattern of their arrangement. In this study we examined the arrangement of orientation pinwheel centers in the cat visual cortex by optical imaging of intrinsic signals. Our results demonstrate that orientation pinwheel centers are arranged in a unique geometric pattern around the area 17/18 transition zone: pinwheel centers of the same type are arranged in rows parallel to the transition zone, and rows of clockwise and counterclockwise pinwheel centers are arranged alternately. We suggest that the areal border imposes a strong restriction on the pattern formation of orientation preference maps in the visual cortex.

Acute cerebral phaeohyphomycosis due to Wangiella dermatitidis accompanied by cerebrospinal fluid eosinophilia

We report a case of cerebral phaeohyphomycosis due to Wangiella dermaitidis in an immunocompetent adult man. His cerebrospinal fluid (CSF) showed pleocytosis with a high eosinophil count but without peripheral blood eosinophilia. The present case suggested that this black yeast-like fungus should be included when the causes of CSF eosinophilia are considered, even though it is an extremely rare pathogen.

Coherent control of absorption and polarization decay in a GaAs quantum well: time and spectral domain studies

Two phase-locked pulses are used to coherently excite excitonic polarizations. It is shown that the second pulse can either be strongly amplified by taking up energy gained from the destruction of the exciton polarization or can be decreased drastically by giving up all its energy to excitons. Both the temporal and the spectral signatures of the transmitted pulse shapes agree well with model calculations.

A tetrodotoxin-producing Vibrio strain, LM-1, from the puffer fish Fugu vermicularis radiatus

Identification of tetrodotoxin (TTX) and its derivatives produced from a Vibrio strain in the intestine of the puffer fish Fugu vermicularis radiatus was performed by thin-layer chromatography, electrophoresis, high-performance liquid chromatography, and gas chromatography-mass spectrometry, together with a mouse bioassay for toxicity. It was demonstrated that the isolated bacterium produced TTX, 4-epi-TTX, and anhTTX during cultivation, suggesting that Vibrio strains are responsible for the toxification of the puffer fish.

Effects of pH and trace minerals on long-term starvation of Leuconostoc mesenteroides

Laboratory experiments have definitively shown that exopolymer-producing bacteria have the potential to modify the flow of fluids in oil reservoirs to enhance oil production. Once injected into the reservoir, they will be subjected to a wide range of pH values and to starvation resulting from nutrient depletion. For successful field implementation it is necessary to have a fundamental understanding of these effects on the viability of bacteria. This paper addresses the effects of pH and trace minerals on cell viability of Leuconostoc mesenteroides during carbon source depletion. Two different carbon sources were used to grow cells before transferring the cells to starvation conditions: sucrose and a combination of glucose and fructose. These substrates were chosen because L. mesenteroides produces a significant amount of water-insoluble exopolymers (dextran) under sucrose-fed conditions, which may enhance cell survival under harsh conditions. The effects of dextran on the cell viability were tested at different pH values with and without trace minerals. The rate of cell death followed an exponential-decay law for different values of the solution pH. The optimal solution pH for survival was pH 5, whereas cells died rapidly at pH 3 and below and at pH 13 and above. The sucrose-fed cells showed a greater viability than cells fed glucose and fructose for all pH ranges tested. The results indicated that water-insoluble exopolymers help cells survive for longer periods of time under starvation conditions. The effects of trace minerals on cell culturability were tested at two pH values, 4.5 and 7. For both cases, cells showed a greater culturability (smaller decay rate constant) in the presence of trace minerals than without trace minerals. It was also found that the effects of trace minerals on cell culturability were greater for glucose-fructose-fed cells than for sucrose-fed cells. The Michaelis pH function theory was used for comparing the relationships between the cell decay rate and pH.

Ice-pack test in myasthenia gravis: electrophysiological basis

We report the first study in which the repetitive nerve stimulation (RNS) test was performed in conjunction with the ice-pack test in three patients with myasthenia gravis. All three patients showed an unequivocal improvement in ptosis on the side where an ice pack was placed. RNS test in the facial nerve revealed a definite improvement in the decremental response. From this we conclude that the ice-pack test produces a clinical and electrophysiological improvement in myasthenia gravis.

Apoptosis of peripheral blood mononuclear cells in Kawasaki disease

OBJECTIVE

Kawasaki disease (KD) is an acute systemic vasculitis characterized by marked depletion of peripheral lymphocytes in the acute stage of the disease. We evaluated the degree of apoptosis of peripheral blood mononuclear cells (PBMC) in KD and investigated whether the Fas-Fas ligand system is involved in inducing apoptosis in KD.

METHODS

Fifteen patients with KD were classified into 2 groups, Group KW1 (initial stage of disease, or fever < 5 days) and Group KW2 (fulminant stage of disease, or fever > 5 days). PBMC were isolated and after 5, 24, and 48 h incubation stained and analyzed by flow cytometry. The levels of serum soluble Fas were measured by ELISA. mRNA expression of Fas ligand was evaluated by reverse transcription polymerase chain reaction.

RESULTS

The degree of apoptosis at 24 h was 20.2 +/- 5.6% in Group KW1, higher than that of normal (p < 0.05) and febrile controls (p < 0.01); and 10.8 +/- 2.8% in Group KW2, lower than that of normal (p < 0.01) and febrile controls (p < 0.01). At 48 h the degree of apoptosis was 37.7 +/- 4.2% in Group KW1, significantly higher than normal (p < 0.01) and febrile controls (p < 0.01); and 17.1 +/- 5.6% in Group KW2, lower than normal (p < 0.01) and febrile controls (p < 0.01). The mean level of serum soluble Fas in the acute stage of KD was 0.45 +/- 0.26 ng/ml, significantly lower versus the subacute stage (1.06 +/- 0.40 ng/ml) (p < 0.01). FasL of mRNA was expressed in PBMC of all patients with acute stage KD. whereas no expression was noted in the subacute stage of disease.

CONCLUSION

Marked decrease of peripheral blood lymphocytes in acute stage KD may be caused by the upregulated apoptosis of lymphocytes; Fas-Fas ligand may be involved in this upregulation.

Aromatase and sulfatase inhibitors from Lepiota americana

From an edible mushroom Lepiota americana Pk., (Agaricaceae), 2-aminophenoxazin-3-one that inhibited aromatase at IC50 = 5.7 microM and 3 beta-hydroxy-5,8-epidioxyergosta-6,22-diene that inhibited sulfatase at IC50 = 0.9 microM were isolated. Neither 2-aminophenoxazin-3-one was active against sulfatase nor was 3 beta-hydroxy-5,8-epidioxyergosta-6,22-diene active against aromatase.

High-resolution mapping of iso-orientation columns by fMRI

Blood-oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is an important tool for localizing brain functions in vivo. However, the ability of BOLD fMRI to map cortical columnar structures is highly controversial, as the ultimate functional specificity of BOLD remains unknown. Here we report a biphasic BOLD response to visual stimulation in the primary visual cortex of cats. In functional imaging, the initial BOLD signal decrease accurately labeled individual iso-orientation columns. In contrast, the delayed positive BOLD changes indicated the pattern of overall activation in the visual cortex, but were less suited to discriminate active from inactive columns.

Reversed-phase high performance liquid chromatographic separation of the enantiomers of terbutaline by derivatization with 2,3,4,6-tetra-o-acetyl-beta-D-glucopyranosyl isothiocyanate

The enantiomers of the bronchodilator terbutaline were separated by reversed-phase high performance liquid chromatography after derivatization with 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate(GITC) reagent. The derivatization proceeded quantitatively within 1 h at room temperature. The corresponding diastereomeric thiourea derivatives were well resolved on an ODS column with acetonitrile-acetate buffer as a mobile phase. Elution orders of the diastereomers were confirmed by derivatization of R-(-)-terbutaline and S-(+)-terbutaline which were collected by semi-preparative chiral HPLC using Sumichiral OA-4700 column. The native fluorescence of terbutaline was quenched by derivatization with GITC. The detection limit was 25 ng when monitored at UV 278 nm.

An optimal dose of perfluorocarbon for respiratory mechanics in partial liquid ventilation for dependent lung-dominant acute lung injury

BACKGROUND

Despite increasing knowledge about partial liquid ventilation (PLV), the optimal dose of perfluorocarbon (PFC) is not yet established. Because there exist normal regions in the lung with ARDS and because PLV in the normal lung results in worsened gas exchange, we postulated that the optimal dose of PFC for PLV may be less than the functional residual capacity (FRC) dose in the lung with limited disease.

DESIGN AND SETTING

Animal study at the Asan Institute for Life Sciences, Seoul, Korea.

SUBJECTS

Twelve rabbits in which dependent lung-dominant lung injury was created by a modified saline solution lavage.

INTERVENTIONS

PLV performed at six different doses of perfluorodecalin in sequence (3, 6, 9, 12, 15, and 18 mL/kg every 15 min).

MEASUREMENTS AND RESULTS

Our modified saline solution lavage induced atelectasis and hemorrhage confined to the dependent lung with severe hypoxia (PaO(2)/fraction of inspired oxygen = 37 +/- 6 mm Hg). Peak airway pressure (Ppeak) and inspiratory pause pressure (Ppause) with PLV were lower at doses of 3 to 15 mL/kg (all p < 0.05), but not different at a dose of 18 mL/kg, when compared with gas ventilation. Ppeak increased at doses of 12, 15, and 18 mL/kg, when each was compared with the preceding PFC dose. At increasing PFC doses, the change in the elastic component of airway pressure (Ppause after minus Ppause before) was negative until the dose of 9 mL/kg, but was positive at doses of 12 mL/kg and above. The change in the resistive component ([Ppeak minus Ppause] after minus [Ppeak minus Ppause] before) was negative until the dose of 6 mL/kg, but was positive at the dose > or = 9 mL/kg.

CONCLUSION

Respiratory mechanics during PLV for dependent lung-dominant lung injury were optimal at a PFC dose less than the FRC.

Genomic organization and sequence of the mud loach (Misgurnus mizolepis) growth hormone gene: a comparative analysis of teleost growth hormone genes

The mud loach (Misgurnus mizolepis) growth hormone (GH) gene was cloned and a comparative analysis on its genomic organization was performed. Based on Southern analysis using various kinds of restriction endonucleases, the GH gene proved to exist as a single-copy gene in the mud loach. The complete nucleotide sequences of a 5.1 kb SacI/EcoRI genomic fragment containing the mud loach GH gene and its 5' flanking sequences as well as a mud loach GH cDNA obtained by rapid amplification of a reverse transcriptase-PCR have been determined. The GH gene spans 2.0 kb from the start codon to the polyadenylation signal, and contains five exons and four introns similar to those of carps and mammals. The evolutionary relation of the mud loach GH gene, inferred by comparative analyses of gene structures and sequences in each exon and intron of representative teleost GH genes, reflects the major phylogenetic groupings of teleost.