Postsynaptic calcineurin activity downregulates synaptic transmission by weakening intracellular Ca2+ signaling mechanisms in hippocampal CA1 neurons

Protein phosphorylation and dephosphorylation are believed to functionally couple neuronal activity and synaptic plasticity. Our previous results indicated that postsynaptic Ca2+/calmodulin (CaM) signaling pathways play an important role in setting synaptic strength, and calcineurin (CaN) activity limits synaptic responses during basal synaptic transmission and long-term potentiation expression. The inhibition of postsynaptic CaN activity by FK-506 or an autoinhibitory peptide induced synaptic potentiation in hippocampal slices, which occludes tetanus-induced LTP. FK-506-induced synaptic potentiation was expressed in adult but not young rats. To elucidate mechanisms underlying CaN-inhibited synaptic potentiation, we co-injected certain agents affecting Ca2+ signaling pathways with CaN inhibitors into CA1 neurons. Synaptic potentiation induced by FK-506 was significantly attenuated by co-injecting BAPTA, heparin/dantrolene (inhibitors of intracellular Ca2+ release), a CaM-binding peptide, or CaM-KII/PKC pseudosubstrate peptides. These results indicate that postsynaptic CaN activity can downregulate evoked synaptic transmission by weakening intracellular Ca2+ signals and downstream protein kinase activities.

Risk factors associated with coronary artery stenosis among patients with chest pain in eastern Taiwan

To analyze the risk factors for coronary artery stenosis among patients who were admitted to the hospital with chest pain in eastern Taiwan, we retrospectively reviewed the clinical data of 444 patients who received coronary arteriography, including 62 aborigines. Results indicated that there were 268 patients (64%) with coronary stenosis. Male to female ratio, mean age, pack-years of cigarette smoking, and hypertension were significantly higher in patients with coronary stenosis (CS group) than in patients without coronary stenosis (control group). There were also significant differences in the serum levels of total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol between the CS and control groups. The total cholesterol and low-density lipoprotein cholesterol of both the CS and control groups were lower than those reported in western Taiwan. The prevalence of coronary stenosis among Taiwanese patients who presented with chest pain was significantly higher than in aborigines (64% vs 38%), although there were no significant differences in common risk factors between these two ethnic groups. These results revealed that the common risk factors in eastern Taiwan were the same as those reported here and suggest that race may be an important risk factor for coronary stenosis.

Crystal structure of ICAM-2 reveals a distinctive integrin recognition surface

Recognition by integrin proteins on the cell surface regulates the adhesive interactions between cells and their surroundings. The structure of the 'I' domain that is found in some but not all integrins, has been determined. However, the only integrin ligands for which structures are known, namely fibronectin and VCAM-1, are recognized by integrins that lack I domains. The intercellular adhesion molecules ICAM-1, 2 and 3 are, like VCAM-1, members of the immunoglobulin superfamily (IgSF), but they are recognized by an I domain-containing integrin, lymphocyte-function-associated antigen 1 (LFA-1, or CD11a/CD18). Here we present the crystal structure of the extracellular region of ICAM-2. The glutamic acid residue at position 37 is critical for LFA-1 binding and is proposed to coordinate the Mg2+ ion in the I domain; this Glu 37 is surrounded by a relatively flat recognition surface and lies in a beta-strand, whereas the critical aspartic acid residue in VCAM-1 and fibronectin lie in protruding loops. This finding suggests that there are differences in the architecture of recognition sites between integrins that contain or lack I domains. A bend between domains 1 and 2 of ICAM-2 and a tripod-like arrangement of N-linked glycans in the membrane-proximal region of domain 2 may be important for presenting the recognition surface to LFA-1. A model of ICAM-1 based on the ICAM-2 structure provides a framework for understanding its recognition by pathogens.

Cyclin-dependent kinase 5 (Cdk5) activation domain of neuronal Cdk5 activator. Evidence of the existence of cyclin fold in neuronal Cdk5a activator

Neuronal Cdk5 activator (Nck5a) differs from other cyclin-dependent kinase (Cdk) activators in that its amino acid sequence is only marginally similar to the cyclin consensus sequence. Nevertheless, computer modeling has suggested that Nck5a contains the cyclin-fold motif recently identified in the crystal structure of cyclin A. In the present study, a number of truncation mutants and substitution mutants of the Nck5a were produced and tested for the Cdk5 activation and Cdk5 binding activity. The active domain of Nck5a determined by using the truncation mutants consists of the region spanning residues 150 to 291. The size of Nck5a active domain is essentially the same as that of cyclin A required for Cdk2 activation (Lees, E. M., and Harlow, E. (1993) Mol. Cell. Biol. 13, 1194-1201). The change, or the lack of change, in Cdk5 activation activity observed with a number of substitution mutants may be understood on the basis of structure and function relationship of cyclin A. These results provide support to the previous suggestion (Brown, N. R., Noble, M. E. M., Endicott, J. A., Garman, E. F., Wakatsuki, S., Mitchell, E., Rasmussen, B., Hunt, T., and Johnson, L. N. (1995) Structure 3, 1235-1247) that the activation domain of Nck5a adopts a conformation similar to that of cyclin A. They also provide a partial answer to the question of how Nck5a, a non-cyclin, activates a cyclin-dependent kinase.

Induction of human endothelial cell apoptosis requires both heat shock and oxidative stress responses

Endothelial cell (EC) death may play an important role in the development of increased vascular permeability and capillary leak syndrome during systemic inflammatory response syndrome. However, the mode of EC death and the mechanisms involved remain unclear. In this study we employed the proinflammatory mediators lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF-alpha), the chemical reagent sodium arsenite, and heat shock to trigger the stress gene responses. Human ECs were used as surrogates of the microvasculature to test the hypothesis that the induction of the heat shock response and the oxidative stress response might combine to induce apoptosis rather than necrosis in human ECs. Sodium arsenite at 80-320 microM, which induced heat shock protein 72 (HSP72) expression and reactive oxygen intermediate (ROI) generation in ECs, resulted in EC apoptosis. TNF-alpha alone (5-75 ng/ml) increased EC ROI generation but did not induce EC apoptosis. Heat shock alone (42 degrees C, 45 min) or sodium arsenite (40 microM) alone, each of which induced HSP72 expression, did not result in EC apoptosis. However, the combination of TNF-alpha with heat shock or 40 microM sodium arsenite led to EC apoptosis as HSP72 expression and ROI were induced. Furthermore, sodium arsenite (80 microM) in the presence of antioxidants failed to induce EC apoptosis. Apoptotic ECs also exhibited functional disturbances as represented by the depression of intercellular adhesion molecule-1 expression as well as the disruption of EC monolayer integrity. These results indicate that the simultaneous induction of a heat shock response and an oxidative stress response is responsible for human EC apoptosis.

Changes of hepatitis B markers among young adults in a hepatitis B virus endemic area: a follow up study on medical students

To elucidate the hepatitis B virus (HBV) infection status of teenagers, to observe changes of the status of these young adults after long-term follow up, to clarify the HBV replication activity of young HBsAg carriers, and to understand the anti-HBs titer of those immune to HBV-infection, a comparison between two health examinations at a 5-or 6-year interval was conducted among 132 medical students. Their ages were 19.1 +/- 0.9 (mean +/- SD). There were 19 (14.4%) HBsAg carriers, 57 (43.2%) immune to HBV infection, and 56 (42.4%) susceptible to HBV. All 19 HBsAg positive carriers were still in carrier status in the second examination. Twelve (63.1%) of the HBV carriers had already HBeAg negative seroconversion before the age of 25. And two carriers might be in the late e seroconversion phase. One susceptible student had a subclinical HBV infection during his university life, with an incidence of HBV infection of 0.47% (1/213) per person-year. Nine (11%) of 82 HBV-immune students had lower anti-HBs concentrations. Six of the 9 students were immunized by natural infection. Anamnestic response developed after booster vaccination. This study shows that these young adults have an HBsAg-carrier rate similar to the general adult population in Taiwan. However, HBeAg seroconversion occurs more often and earlier in this particular population than previous reports have indicated. Moreover, only 24 (40%) susceptible subjects received HBV vaccination after the first recommendation and it is necessary to be more forceful in recommending prompt vaccination.

Induction of heat shock protein 72kDa expression is associated with attenuation of ischaemia-reperfusion induced microvascular injury

Leukocyte-endothelial interaction is a pivotal step in the pathogenesis of ischemia-reperfusion (I/R) injury. Exposure of cells to a subcritical heat stress may protect cells from subsequent I/R injury, through induction of a 72-kDa heat shock protein (HSP72). The aim of this study was to investigate the effect of thermotolerance on leukocyte adherence and migration during an I/R period in rat mesenteric postcapillary venules. Sprague-Dawley rats were randomized into control (sham I/R), I/R, and thermotolerance+I/R groups. Thermotolerance was induced 18 hr prior to I/R, which was in turn established by occlusion of the superior mesenteric vascular pedicle for 10 mins, followed by 60 mins of reperfusion. The blood flow, leukocyte rolling velocity, and the number of adherent and migrated leukocytes in postcapillary venules were measured by intravital microscopy. I/R significantly decreased the rolling velocity of leukocytes; increased the number of adherent leukocytes at 10, 30, and 60 mins after reperfusion; and also increased the number of migrated leukocytes at 60 mins after reperfusion. Thermotolerance induction expression of HSP72 in pulmonary, intestinal, and mesenteric tissues was determined by Western immunoblotting. Thermotolerance significantly prevented the I/R-induced decrease in rolling velocity of leukocytes, the increase in the number of adherent leukocytes at 30 and 60 mins, and the increase in the number of migrated leukocytes at 60 mins. This results suggest that thermotolerance attenuates I/R injury by modulating leukocyte-endothelial interaction in vivo, possibly by increasing tissue expression of HSP72.

Effect of corticosteroids on release of RANTES and sICAM-1 from cultured human bronchial epithelial cells, induced by TNF-alpha

We have recently demonstrated that human bronchial epithelial cells can synthesise and release several inflammatory mediators, including the factor regulated on activation, normal T-cell expressed and secreted (RANTES) and soluble intercellular adhesion molecule-1 (sICAM-1), which influence the activity of eosinophils, and may, therefore play a role in the aetiology of asthma. In this study we investigated whether corticosteroids could influence the release of these proinflammatory mediators from human bronchial epithelial cells. Human bronchial epithelial cells were cultured to confluence as explant cultures, and incubated in the presence of 50 ng x mL(-1) tumour necrosis factor-alpha (TNF-alpha) +/- 0-10(-4) M of either fluticasone propionate (FP), beclomethasone dipropionate (BDP), or hydrocortisone (HC) for 24 h. The culture medium was collected and analyzed for RANTES and sICAM-1, by enzyme-linked immunosorbent assay (ELISA), and the cells were analysed for total protein. The TNF-alpha significantly increased the release both of RANTES and sICAM-1 (63.0 fg RANTES x microg(-1) protein; p<0.05; 8.8 pg sICAM-1 x microg(-1) protein; p<0.02), when compared with untreated cells (10.3 fg RANTES x microg(-1) protein; 2.6 pg sICAM-1 x microg(-1) cellular protein). The TNF-alpha-induced release both of RANTES and sICAM-1 occurred in a time-dependent manner, and was maximal by 24 h incubation. FP 10(-6)-10(-4) M significantly attenuated the TNF-alpha-induced release both of RANTES and sICAM-1. In contrast, 10(-4) M BDP or HC significantly attenuated the release of only sICAM-1. These results suggest that corticosteroids may prevent airway inflammation by downregulating the synthesis and/or release of proinflammatory mediators from bronchial epithelial cells. Furthermore, fluticasone propionate may be more efficacious than beclomethasone dipropionate or hydrocortisone in this respect.

Effect of corticosteroids on release of RANTES and sICAM-1 from cultured human bronchial epithelial cells, induced by TNF-alpha

We have recently demonstrated that human bronchial epithelial cells can synthesise and release several inflammatory mediators, including the factor regulated on activation, normal T-cell expressed and secreted (RANTES) and soluble intercellular adhesion molecule-1 (sICAM-1), which influence the activity of eosinophils, and may, therefore play a role in the aetiology of asthma. In this study we investigated whether corticosteroids could influence the release of these proinflammatory mediators from human bronchial epithelial cells. Human bronchial epithelial cells were cultured to confluence as explant cultures, and incubated in the presence of 50 ng x mL(-1) tumour necrosis factor-alpha (TNF-alpha) +/- 0-10(-4) M of either fluticasone propionate (FP), beclomethasone dipropionate (BDP), or hydrocortisone (HC) for 24 h. The culture medium was collected and analyzed for RANTES and sICAM-1, by enzyme-linked immunosorbent assay (ELISA), and the cells were analysed for total protein. The TNF-alpha significantly increased the release both of RANTES and sICAM-1 (63.0 fg RANTES x microg(-1) protein; p<0.05; 8.8 pg sICAM-1 x microg(-1) protein; p<0.02), when compared with untreated cells (10.3 fg RANTES x microg(-1) protein; 2.6 pg sICAM-1 x microg(-1) cellular protein). The TNF-alpha-induced release both of RANTES and sICAM-1 occurred in a time-dependent manner, and was maximal by 24 h incubation. FP 10(-6)-10(-4) M significantly attenuated the TNF-alpha-induced release both of RANTES and sICAM-1. In contrast, 10(-4) M BDP or HC significantly attenuated the release of only sICAM-1. These results suggest that corticosteroids may prevent airway inflammation by downregulating the synthesis and/or release of proinflammatory mediators from bronchial epithelial cells. Furthermore, fluticasone propionate may be more efficacious than beclomethasone dipropionate or hydrocortisone in this respect.

Plasma factors augment neutrophil and endothelial cell activation during aortic surgery

Lung injury following reperfusion results from endothelial damage caused by release of cytotoxic products by activated neutrophils (PMN) in the pulmonary microvasculature. This process is facilitated by the release of pro-inflammatory cytokines and arachidonic metabolites following the outset of reperfusion. This study aimed to evaluate the effect of plasma obtained before and after revascularisation on neutrophil and endothelial cell activation. Plasma (IR-plasma) was obtained from venous blood samples taken before and during aortic cross-clamping, and 5, 40 and 60 min following clamp removal in seven patients undergoing elective infrarenal aortic aneurysm resection. PMN from healthy volunteers (n = 5) were incubated with these plasma samples or with fMLP (N-formylmethionyl-leucyl-phenylalanine) as positive control for 30 min and assessed flow-cytometrically for CD11b expression. Human endothelial cells (ECV-304) were incubated with IR plasma for 2, 4 and 6 h or with tumour necrosis factor (TNF) (20 ng/ml) as positive control and assessed for ICAM-1 expression. Incubation with IR plasma resulted in a significant increase from pre-clamp in PMN CD11b expression. A similar trend was seen in endothelial cell ICAM-1 expression following 2 h incubation. These results indicate that reperfusion-induced endothelial dysfunction may be mediated by plasma factors released upon revascularisation which facilitate neutrophil-endothelial interaction through up-regulation of adhesion receptor expression.

Hepatic focal nodular hyperplasia: findings on color Doppler ultrasound

BACKGROUND

We assessed the color Doppler ultrasound (US) findings in focal nodular hyperplasia (FNH).

METHODS

Seven FNH lesions were imaged with color Doppler US and hepatic angiography.

RESULTS

In four lesions, color Doppler demonstrated a central stellate vascular appearance which correlated with central feeding artery with spoke-wheel sign angiographically. Except for one lesion, color Doppler US imaging correlated with angiographic findings.

CONCLUSIONS

Color Doppler US is capable of demonstrating the typical findings of a central feeding artery and stellate vascular pattern in many cases of FNH.

A comparative study of nonoperative versus operative treatment of developmental dysplasia of the hip in patients of walking age

We retrospectively reviewed our results of treatment of two groups of children with developmental dysplasia of the hip (DDH) aged between 13 and 17 months. The nonoperative group consisted of 16 patients (17 hips) who were treated by closed reduction and casting with or without skin traction. There were four hips with mild degrees of avascular necrosis, and one hip with a failed reduction. Before further treatment, there were one hip in Severin class I, nine in class III, six in class IV, and one in class VI. Subsequent open reduction or pelvic osteotomy was required in those hips with failed reduction and residual dysplasia. The operative group consisted of 32 patients (32 hips). Open reduction and Salter osteotomy were performed without preoperative traction. There was one hip with redislocation due to improper use of a short spica and two hips with a mild degree of avascular necrosis. In > 2 years and 3 months of follow-up, 13 hips were in Severin class I, 18 in class II, and one in class III. The treatment time was significantly shortened in the operative group. We conclude that neglected DDH in patients of walking age can be safely and effectively treated by open reduction plus Salter osteotomy.

Neuronal Cdc2-like kinase (Nclk) binds and phosphorylates the retinoblastoma protein

The tumor suppressor retinoblastoma protein (RB) plays a central role in cellular growth regulation, differentiation, and apoptosis. Phosphorylation of RB results in a consequent loss of its ability to inhibit cell cycle progression. However, how RB phosphorylation might be regulated in apoptotic or postmitotic cells, such as neurons, remains unclear. Here we report that neuronal Cdc2-like kinase (Nclk), composed of Cdk5 and a neuronal Cdk5 activator (p25(nck5a)), can bind and phosphorylate RB. Since RB has been shown recently to associate with D-type G1 cyclins and viral oncoproteins through a common peptide sequence motif of LXCXE, Nclk binding may be mediated by a related sequence motif (LXCXXE) found in p25(nck5a). We demonstrate (i) in vitro binding of bacterially expressed p25(nck5a) to a GST-RB fusion protein, (ii) coprecipitation of GST-RB and reconstituted Cdk5.p25(nck5a), and (iii) phosphorylation of GST-RB by bacterially expressed Cdk5.p25(nck5a) kinase and by Cdk5.p25(nck5a) kinase purified from bovine brain. Finally, we show that immunoprecipitation of RB from embryonic mouse brain homogenate results in the coprecipitation of Cdk5 and that Cdk5 kinase activity is maximal during late embryonic development, a period when programmed cell death of developing neurons is greatest. Taken together, these results suggest that Nclk can bind to and phosphorylate RB in vitro and in vivo. We infer that Nclk may play an important role in regulating the activity of RB in the brain, including perhaps in apoptosing neurons.

A continuous method for measuring calpain activity

A simplified methodology for assaying the caseinolysis by calpains was developed. This methodology, including the incubation of calpain with casein and direct measurement of the absorbance at 500 nm, is based on the turbidity of the reaction mixture caused by the aggregation of hydrolysates during the reaction. Unlike the typical caseinolysis assay, this novel assay does not need to separate the substrate from hydrolysates and can be continuously monitored in visible wavelength range. The activity of calpain is expressed by the maximum reaction velocity (delta A500/min) at 25 degrees C).

Allergen-irritant interaction and the role of corticosteroids

Studies of exposure to air pollutants, such as ozone and nitrogen dioxide (NO2) +/- sulphur dioxide (SO2), have demonstrated that these agents, either individually or in combination, increase the airway response of both asthmatics and allergic rhinitics to inhaled allergen. Other studies have demonstrated that exposure to these pollutants significantly increased the levels of eosinophil cationic protein (ECP) in the nasal secretions of both asthmatics and allergic rhinitics, suggesting that pollutants may prime eosinophils for subsequent activation by allergen. More recently, our studies have demonstrated that treatment with inhaled corticosteroids, such as fluticasone propionate, significantly attenuated pollution+ allergen-induced release of ECP in allergic rhinitics. Although the mechanisms underlying the potentiating effects of pollutants on allergen-induced changes in the airways of allergic individuals are not fully understood, in vitro studies have suggested that airway epithelial cells may play an important role, since they can synthesize a variety of cytokines and adhesion molecules which influence the activity of eosinophils and other inflammatory cells. Studies of nasal epithelial cells cultured from biopsies of atopic rhinitic and atopic non-rhinitic individuals have shown that they constitutively release significantly greater quantities of pro-inflammatory cytokines than nasal epithelial cells of non-atopic individuals, and that the release of these cytokines is greater from cells of atopic rhinitics during the pollen season. Furthermore, exposure of the cells of rhinitics to ozone led to an even greater release of these cytokines, and this effect was attenuated by treatment with fluticasone propionate and beclomethasone dipropionate.

[Study of the effects of pulse magnetic fields on hemorrheology of human body]

The results show that middle shear specific viscosity and reductive viscosity (P<0.05), low shear specific viscosity and reductive viscosity of whole blood (P<0.01) decreased significantly in experimental group after 9-day of pulse magnetic fields, comparing with control group, high shear specific viscosity, low shear reductive viscosity (P<0.05) and middle and low shear specific viscosity (P<0.01) of whole blood in experimental group were lower after exposed than before exposed to pulse magnetic fields. The results suggest that the pulse magnetic fields may reduce specific and reductive viscosity of whole blood in human body.

Cryptococcal meningitis and primary CNS lymphoma in a patient with acquired immunodeficiency syndrome: a case report

This report describes a case of cryptococcal meningitis as the initial manifestation of acquired immunodeficiency syndrome (AIDS). During the admission, computed tomography (CT) of brain revealed multiple lesions with ring-enhancement over the cerebellum, frontal and temporal lobes. Autopsy findings showed diffuse cryptococcal meningoencephalitis and central nervous system (CNS) lymphoma forming multiple round ring abscesses. The case demonstrated that opportunistic cryptococcal infection and primary CNS lymphoma may coexist in a patient with AIDS.

Clinical utility of color Doppler sonography in the differentiation of hepatocellular carcinoma from metastases and hemangioma

The clinical utility of color Doppler sonography in the differentiation of hepatocellular carcinoma from metastases and hemangioma was investigated in 72 hepatocellular carcinomas (80 lesions), 30 metastases (82 lesions), and 39 hemangiomas (54 lesions). Overlaps of color patterns were found among hepatocellular carcinoma, metastases and hemangioma. Pulsatile waves from lesions with the basket, vessels within tumor, or spot patterns, or lesions measuring less than 3 cm with detectable signals, did not favor the diagnosis of hemangioma. In conclusion, color Doppler sonography can aid in the differentiation of hepatocellular carcinoma from hemangioma but may be unreliable in the differentiation of hepatocellular carcinoma from hypervascular metastases.

Bronchial inflammation and the common cold: a comparison of atopic and non-atopic individuals

Background Cold virus infections are associated with asthma attacks and with increased bronchial responsiveness even in normal subjects. Possible mechanisms include epithelial damage, interaction with adhesion molecules or with T‐helper cell subsets.

Objective To determine whether colds increase lower airway inflammation, comparing atopic with non‐atopic normal subjects.

Methods Thirty healthy volunteers (15 atopic) took part. Basehne tests included viral serology. microbiological culture and polymerase chain reaction for rhinovirus infection (HRV‐PCR), histamine bronchial provocation and bronchoscopy. Twenty subjects (eight atopic) underwent repeat tests when they developed a cold.

Results Forced expiratory volume in one second (FEV₁) was significantly lower during colds (‐0.19L [95% confidence mterval ‐0.10, ‐0.29], P= 0,0004) and there was a significant increase in bronchial responsiveness (+0.62 doublings of the dose‐response slope [+0.24, +1.00], P=0.003). Eight subjects (two atopic) had a diagnosed viral infection: two HRV. three coronavirus (HCV), one HRV + HCV, one parainfluenza III(PI) and one respiratory syncytial virus (RSV) (also Haemophilus influenzae). In biopsies, during colds, total eosinophils (EG1⁺) increased significantly (geometric mean 6.73‐fold [1.12,40.46], P=O.04). Activated eosinophils (EG2⁺) only increased significantly in the subgroup without diagnosed viral infection and particularly in atopic rhinitics. T‐suppressor (CD8⁺) cells also increased significantly (median +178.3 cells mm², P= 0.004). Epithelial expression of intercellular adhesion molecule‐1 (ICAM‐1) expression increased in four atopic rhinitics during colds. Bronchial washings showed a significant increase in neutrophils (GM 1.53‐fold [1.04,2.25], P= 0.02).

Conclusion Lower airway inflammation was present in atopic and non‐atopic normal subjects with colds. Atopic subjects differed in that they were less likely to have positive virological tests and were more likely to show activated eosinophilia in the lower airway, despite a similar spectrum of symptoms.

Developmental alteration of the expression and kinase activity of cyclin-dependent kinase 5 (Cdk5)/p35nck5a in the rat retina

Neuronal Cdc2-like kinase has been purified from the bovine brain as a proline-directed serine/threonine kinase. This kinase is a heterodimer of Cdk5 and p35nck5a and influences neuronal maturation or sprouting in the normal brain. In this study, we showed the expression of Cdk5/p35nck5a kinase in the developing rat retina. The expression of Cdk5 and p35nck5a increased between 1 week and 3 weeks after birth. These expression levels were most prominent from 2 weeks to 3 weeks after birth and decreased after 4 weeks. The developmental change of Cdk5/p35nck5a kinase activity coincided with those of the expression of p35nck5a and Cdk5. An immunohistochemical study showed that Cdk5 was expressed in the ganglion cells and in some cells in the inner nuclear layer at an early stage. With retinal development, Cdk5 was expressed in the inner plexiform layer also. In the adult, the expression of Cdk5 was restricted to the inner plexiform layer and to some cells in the inner nuclear layer. These changes of localization in the developing retina were very close to those of B-50/GAP-43. On the other hand, the expression of p35nck5a was restricted to the soma of the neuron in the developing retina. This subcellular localization in the developing retina agreed with that in the developing rat brain. The expression levels of Cdk5 and p35nck5a in retina of rats raised from fetus to 3 weeks after birth in darkness were 36% and 40% respectively, of the baseline for control rats. Moreover, the kinase activity in rats raised in darkness was lower than that in control rats. These data suggest that Cdk5/p35nck5a may play a role in neuronal plasticity in the developing rat retina.

Taurine attenuates nitric oxide- and reactive oxygen intermediate-dependent hepatocyte injury

OBJECTIVE

To evaluate the potential role of the semi-amino acid taurine in the prevention of hepatocyte (HC) apoptosis and necrosis mediated by nitric oxide (NO) and reactive oxygen intermediates.

DESIGN

Isolated rat HCs were cultured with lipopolysaccharide (LPS), antioxidants, taurine, and sodium nitroprusside to examine the effect of these agents on HC injury.

RESULTS

Lipopolysaccharide, in the presence of antioxidants, led to HC apoptosis, while LPS alone failed to induce HC apoptosis. Taurine significantly attenuated LPS plus antioxidant-mediated HC apoptosis, and this correlated with taurine-mediated NO inhibition. Taurine also significantly reduced LPS-mediated hepatocellular enzyme release and HC necrosis, and this correlated with HC free radical and peroxynitrite inhibition. However, taurine did not prevent sodium nitroprusside-mediated HC apoptosis and necrosis.

CONCLUSIONS

Taurine attenuates HC apoptosis and necrosis through inhibition of both NO and reactive oxygen intermediate. While taurine acts directly as an antioxidant, its effects on NO may occur at the messenger RNA level. Our findings indicate a potential prophylactic and therapeutic role for this amino acid during systemic inflammatory response syndrome.

Malakoplakia of the prostate forming a fistulous tract to rectum: a case report

Malakoplakia is a rare lesion of granulomatous inflammation which mainly affects urinary bladder but may involve other parts of the body. Differentiation from neoplastic process is often difficult due to its tumorous gross appearance and similarity to carcinoma microscopically. Malakoplakia of the prostate is even rare. We present a case of prostatic malakoplakia masquerading as a rectal tumor due to formation of a fistulous tract to the rectal muscular layers accompanied with ulceration of the rectal mucosa. Its clinical course is different from those of most reported cases, while the outcome is as satisfactory as in usual cases.

Treatment of carbon monoxide poisoning with hyperbaric oxygen

BACKGROUND

Carbon monoxide poisoning is a major cause of accidental morbidity and mortality in Taiwan. Utilization of hyperbaric oxygen in severely carbon monoxide intoxicated patients has been investigated widely. The object of this study was to determine the nature of carbon monoxide poisoning and to evaluate the effect of hyperbaric oxygen therapy for such patients.

METHODS

Retrospective analysis of 34 consecutive carbon monoxide intoxicated patients by review of medical records and clinical follow-up for the past three years.

RESULTS

Subjects were 10 males and 24 females, aged 12 to 82 years. The source of the poisoning in 25 cases was faulty-operating heating systems; in 4, incomplete combustion of automobile engine; in 3, use of alternative sources of energy for indoor cooking and heating; in 2, smoke inhalation in fire accidents. All had neurologic symptoms; five also had cardiovascular symptoms and one developed delayed neurologic sequelae. The group with poor outcome after hyperbaric oxygen therapy (n = 10) had higher serum CK values, lower Glasgow coma scale, longer delay in the first aid at emergency service and longer delay in provision of hyperbaric oxygen therapy.

CONCLUSIONS

It was concluded that hyperbaric oxygen therapy is an effective method in treating carbon monoxide intoxicated patients. Understanding the pathogenesis of carbon monoxide poisoning and indications for hyperbaric oxygen therapy will help physicians manage such patients earlier and more adequately. Information on currently available hyperbaric facilities in Taiwan is necessary for timely transfer.

Selective defects in the development of the fetal and adult lymphoid system in mice with an Ikaros null mutation

Mice homozygous for an Ikaros null mutation display distinct defects in the development of fetal and adult lymphocytes. Fetal T lymphocytes, and fetal and adult B lymphocytes and their earliest progenitors are absent. Postnatally, hematopoietic stem cells give rise to thymocyte precursors that undergo aberrant differentiation into the CD4 lineage and clonal expansion. The lack of NK cells and some gamma delta T cell subsets and a large reduction in thymic dendritic APCs suggest that Ikaros is essential for establishing early branch points in the postnatal T cell pathway. The lymphoid defects detected in Ikaros null mice reveal critical molecular differences between fetal and postnatal hematopoietic progenitors that dictate their ability to give rise to T cells. These studies also establish Ikaros as a tumor suppressor gene acting during thymocyte differentiation. Phenotypic comparison of this null mutation with a severe dominant-negative Ikaros mutation identifies molecular redundancy in the postnatal hemolymphoid system.

The genotypes of hepatitis C virus in patients with chronic hepatitis C virus infection in southern Taiwan

To investigate the genotype distribution of hepatitis C virus (HCV) in southern Taiwan, the sera from 56 patients with chronic HCV infection were studied. Twenty-nine patients were men and 27 were women. Age ranged from 22 to 65 years (mean, 47.3 +/- 11.4). Eighteen of them had chronic persistent hepatitis, 27 had chronic active hepatitis, and 11 had liver cirrhosis. HCV RNA was detected by reverse transcription-nested polymerase chain reaction using primers derived from the 5'-noncoding region. The genotypes of HCV were determined by amplification of the core region with the type-specific primers as described by Okamoto et al.. All sera were positive for HCV RNA. The prevalence rates of genotypes were as follows: 1b/II, 44.6%(25/56); 2a/III, 41.1%(23/56); 2b/IV, 3.6%(2/56); mixed 1b/I + 2a/III, 5.4%(3/56): mixed 1b/II + 2b/IV, 1.8%(1/56) and type unclassified 3.6%(2/56). The distribution of genotypes was not related to the patients' age, sex, and histological changes. Nevertheless, patients having past history of blood transfusion had a significantly higher rate of HCV type 2a/III infection (72.2% versus 34.2%, p < .05, chi-square test). We concluded that both of the HCV genotypes 1 b/II and 2a/III are predominant types in southern Taiwan and regional HCV genotype distribution may differ even within this island. Selective transmission of specific genotypes may pass along different infectious routes.