Subtotal nephrectomy stimulates cyclooxygenase 2 expression and prostacyclin synthesis in the rat remnant kidney

BACKGROUND: Recently, two isoforms of cyclooxygenase (COX) have been identified, a constitutive form (COX-1) and a mitogen-inducible form (COX-2). Several studies have suggested that COX is activated in renal insufficiency, but little is known about the relationship between progression of renal insufficiency and the COX isoforms. METHODS: Five-sixths-nephrectomized (NX) rats were used. 4, 8, and 12 weeks after nephrectomy, the renal cortical prostaglandin contents and the expression levels of the two isoforms of COX were determined by enzyme immunoassay and Western-blotting, respectively. The localization of COX was examined by immunohistochemistry. RESULTS: Renal cortical prostacyclin (PGI2) and COX-2 were significantly upregulated 8 and 12 weeks after NX, while COX-1 remained at the basal level. There was a high correlation between COX-2 and creatinine clearance (r = -0.845). There was also a high correlation between COX-2 and PGI2 (r = 0.816). Immunohistochemistry revealed the expression of COX-2 to be enhanced in the macula densa in NX rats. CONCLUSIONS: Renal cortical COX-2 and prostacyclin were upregulated corresponding to the progression of renal insufficiency in NX rats. These results suggest enhancement of COX-2 expression in the macula densa, perhaps stimulated by a decrease in renal blood flow which upregulates PGI2 synthesis to protect the kidney from ischemia in renal insufficiency.     

Peritoneal inflammatory cells in acute pancreatitis: Relationship of infiltration dynamics and cytokine production with severity of illness

BACKGROUND: The purpose of this study was to clarify the still poorly understood dynamics of peritoneal inflammatory cells (PICs) in acute pancreatitis. METHODS: Acute pancreatitis of 3 different degrees of severity was induced in male Wistar rats. Peritoneal lavage was performed at 1, 6, 12, and 24 hours after the induction, and the fluids collected were analyzed for the number and subpopulation of PICs. The levels of apoptosis and necrosis, cytokines, and bacterial infection were also investigated. RESULTS: The number of PICs was increased in mild and moderate pancreatitis, and the infiltration of inflammatory cells had occurred. In severe pancreatitis, the number of PICs increased until 6 hours after the induction, but thereafter the number decreased. Infiltration of neutrophils occurred 6 hours after the induction, but it was not sustained thereafter and infiltration of peritoneal macrophages did not occur. Cytokines in the lavage fluid increased in all 3 models during the first 6 hours after the induction. Subsequently, cytokines were reduced in mild and moderate pancreatitis but significantly increased in severe pancreatitis. The level of bacterial infection increased according to the severity. CONCLUSIONS: The relationship between the PIC dynamics and cytokine levels in severe pancreatitis is very different from that observed in mild or moderate pancreatitis.     

Specific therapy of digoxin intoxication in dogs by hybrid kidney overexpressing multidrug resistance protein

BACKGROUND: We have recently developed a unique hybrid artificial kidney, where the proximal tubular cell line, over-expressing multidrug resistance protein, MDR-1 (PCTL-MDR), was cultured on hollow fibers. While this module efficiently removed digoxin in vitro, its efficacy in vivo remained to be determined. METHODS: The system was scaled up by connecting 10 similar modules in parallel, with the MDR-1 (PCTL-MDR) overexpressed proximal tubular cell line cultured as in our previous study. The system was connected to dogs intoxicated with digoxin, a representative substrate of MDR-1. Blood was circulated for 90 minutes through the system. Arterial and venous blood concentrations of digoxin and inulin were monitored. Complete blood cell count and granulocyte elastase were measured before and at the end of the study. RESULTS: By using the system with PCTL-MDR, the arterial digoxin concentration was dramatically decreased from 2.89 +/- 0.10 to 0.92 +/- 0.11 ng/mL, but not by the system with PCTL alone. The clearance was 22.4 +/- 2.1 and 1.5 +/- 0.2 mL/min for the PCTL-MDR and PCTL equipment, respectively. Inulin was not transported in either system. White blood cell and platelet counts were slightly reduced by the treatment while hematocrit was unchanged; the granulocyte elastase concentration was slightly increased. CONCLUSION: These data suggest that our new type of hybrid kidney can selectively remove digoxin sufficiently to reduce its systemic blood concentration in dogs with digoxin intoxication. Taking previous studies into consideration, this system may be a more powerful tool for the treatment of intoxication.     

Cerebral blood flow and vasodilatory capacity in anemia secondary to chronic renal failure

BACKGROUND: Our previous study reported that cerebral oxygen extraction fraction (OEF) increased in hemodialysis patients with anemia. The increased OEF suggests that the cerebral vasodilatory capacity might be impaired in these patients. To clarify this issue, we measured the CO2 response in patients with anemia secondary to chronic renal failure (CRF) using positron emission tomography (PET). METHODS: Ten anemic patients with CRF (6 females and 4 males) and 6 age-matched normal controls were studied. The underlying diseases of CRF were glomerulonephritis in 8 patients, systemic lupus erythematosus (SLE) in one patient, and hypertension in one patient; in this cohort, 5 patients were on hemodialysis treatment and the remaining 5 patients were in a pre-hemodialysis state. The cerebral blood flow (CBF) was measured by the O-15 H2O bolus injection method with each patient in a resting state and during 5% CO2 inhalation. The CO2 response was estimated as the percentage change of CBF per 1 mm Hg change of PaCO2. RESULTS: The CO2 response was significantly attenuated in anemic patients with CRF in comparison to the normal controls, and it inversely correlated with the severity of anemia. There was no significant difference in the CO2 response between the hemodialysis and pre-hemodialysis patients. The CO2 response significantly correlated with CBF and the cerebral metabolic rate for oxygen (CMRO2) at rest, however, it did not correlate with OEF and cerebral blood volume (CBV). CONCLUSIONS: The present study revealed the existence of a reduced cerebral vasodilatory capacity in anemic patients with CRF, suggesting that chronic hypoxic brain damage might play a role in the impaired cerebrovascular response to CO2.     

Cp50 of propofol for laryngeal mask airway insertion using predicted concentrations with and without nitrous oxide

This study sought to determine the predicted Cp50 of propofol required for laryngeal mask airway insertion (Cp50LMA) and to investigate whether nitrous oxide reduces these required concentrations. Using target-controlled infusion and incorporating the standard Diprifusor pharmacokinetic model, 46 unpremedicated patients were randomly assigned to one of two groups. The patients received either 40% oxygen in air (control group: n = 23), or 60% nitrous oxide in oxygen (nitrous oxide group: n = 23). The target concentration for each patient was determined using the up and down method. Following equilibration between the predetermined blood and effect site concentrations, had been established for > 10 min, laryngeal mask airway insertion was attempted without neuromuscular relaxants. The data were analysed using a probit analysis to obtain Cp50LMA levels. The values for Cp50LMA were 3.24 micro g.ml-1 in the control group and 1.93 microg.ml-1 in the nitrous oxide group.     

Congenital absence of the right upper lobe of the lung

We report a patient with an absent right lobe of the lung, a very rare anomaly. A superior lobectomy was performed for adenocarcinoma, and the right upper bronchus and pulmonary artery of the upper lobe (truncus superior) were absent. The first artery originating from the right main pulmonary artery was located at the major fissure, and four relatively small arteries entered the superior lobe. Anatomically, in this patient, the superior lobe was determined to be the middle lobe. The natural upper lobe was missing.     

Myocardium tissue ablation with high-peak-power nanosecond 1,064- and 532-nm pulsed lasers: influence of laser-induced plasma

BACKGROUND AND OBJECTIVES: We investigated the mechanism and characteristics of porcine myocardium tissue ablation in vitro with nanosecond 1,064- and 532-nm pulsed lasers at laser intensities up to approximately 5.0 GW/cm(2). Particular attention was paid to study the influence of the laser-induced plasma on the ablation characteristics. The applicability of these two lasers to transmyocardial laser revascularization (TMLR) was discussed. STUDY DESIGN/MATERIALS AND METHODS: Porcine myocardium tissue samples were irradiated with 1,064- and 532-nm, Q-switched Nd:YAG laser pulses, and the ablation depths were measured. The temporal profiles of the laser-induced optical emissions were measured with a biplanar phototube. For the ablated tissue samples, histological analysis was performed with an optical microscope and a polarization microscope. RESULTS: The ablation efficiency at 1,064 nm was higher than that at 532 nm. The ablation threshold at 1,064 nm (approximately 0.8 GW/cm(2)) was lower than that at 532 nm (approximately 1.6 GW/cm(2)), in spite of the lower absorption coefficient being expected at 1,064 nm. For the 1,064-nm laser-ablated tissues, thermal damage was very limited, while damage presumably caused by the mechanical effect was observed in most of the cases. For the 1,064-nm laser ablation, the ablation threshold was equal to the threshold of the laser-induced optical emission (approximately 0.8 GW/cm(2)), while for the 532-nm laser ablation, the optical emission threshold ( approximately 2.4 GW/cm(2)) was higher than the ablation threshold. CONCLUSIONS: We considered that for the 1,064-nm laser ablation, the tissue removal was achieved through a photodisruption process at laser intensities of > approximately 0.8 GW/cm(2). At laser intensities of > 3.0 GW/cm(2), however, the ablation efficiency decreased; this can be attributed to the absorption of incoming laser pulses by the plasma. For the 532-nm laser ablation, the tissue removal was achieved through a photothermal process at laser intensities of > approximately 1.6 GW/cm(2). At laser intensities of > 2.4 GW/cm(2), a photodisruption process may also contribute to the tissue removal, in addition to a photothermal process. With regard to the ablation rates, the 1,064-nm laser was more suitable for TMLR than the 532-nm laser. We concluded that the 1,064-nm Q-switched Nd:YAG laser would be a potential candidate for a laser source for TMLR because of possible fiber-based beam delivery, its compact structure, cost effectiveness, and easy maintenance. Animal trials, however, have to be carried out to evaluate the influence of the tissue damage.     

Skin problems among fiber-glass reinforced plastics factory workers in Japan

Two surveys, one in winter the other in summer time, examined the skin problems of the entire manual workers (N=148) from 11 small-to-medium sized fiber-glass reinforced plastics (FRP) factories located in Kyushu, Japan. The workers were exposed to unsaturated polyester resin, including styrene and auxiliary agents such as cobalt naphthenate, hardeners such as methyl ethyl ketone peroxides, glass fiber and dust including shortened glass fiber and plastic particles. Eighty-seven workers (58.8%) reported having skin problems (mainly itching or dermatitis) since they started to work in FRP manufacturing and 25 workers had consulted a physician because of their skin problems; one worker was forced to take sick leave because of his severe dermatitis. History of allergic diseases and shorter occupational period (duration of employment) in a FRP factory were associated with greater probability of having a history of work-related skin symptoms. Workers in factories where dust-generating and lamination sites were located in different buildings were significantly less likely to have a history of skin problems than those in factories where the two sites were located in the same building. Of the 67 workers examined in both seasons closed to double the prevalence of dermatitis was found in summer (23.3%) than winter (13.4%).     

Acute transverse myelitis after Japanese B encephalitis vaccination in a 4-year-old girl

Fourteen days after Japanese B encephalitis (JBE) vaccination, a 4-year-old girl developed the full clinical manifestation of ATM within 24h. She showed acute ascending flaccid paraplegia with sensory disturbance, bladder dysfunction and meningeal sign. Cerebrospinal fluid examination revealed neutrophil pleocytosis and elevated protein level. Magnetic resonance imaging (MRI) showed diffuse swelling of the cervical and lumbar cord with low signal intensity on T1 and high signal intensity on T2-weighted imaging. These findings suggested that she had developed meningo-radiculomyelopathy.Since sequential MRI studies showed prompt reduction of the cord swelling, the high-dose methylprednisolone therapy employed seemed to have been effective for improvement of inflammation. Even with such potent drug treatment, she still has substantial flaccid diplegia and sphincter disorder 1 year later, and so we are convinced that the pathological change of the cord was as severe as in necrotizing myelopathy. Although the pathological process remains unknown, cellular autoimmune mechanism against the JBE vaccination is suspected.