Evaluation of risk factors for nephrotoxicity associated with high-dose vancomycin in Japanese patients.

Introduction: Considering the physique of the Japanese population, the standard daily vancomycin dose of 2 g/day and doses ≥ 3 g/day are high in terms of dose per body weight. Studies have reported that administering high-dose vancomycin to achieve a high target trough concentration has been associated with nephrotoxicity. The risk of high-dose vancomycin-associated nephrotoxicity is believed to be exceptionally high for Japanese patients because of their relatively low body weights, but data on the population is lacking. In this retrospective study, we aimed to evaluate risk factors associated with nephrotoxicity in Japanese patients treated with vancomycin. Methods: We examined the medical records of 107 Japanese patients who received vancomycin (3 to 4 g/day). They were divided into two groups based on the presence or absence of nephrotoxicity, and their demographics and clinical characteristics were compared. Results : The incidence of nephrotoxicity in patients receiving high-dose vancomycin was 13%. Age (≥ 60 years) and concurrent use of piperacillin/tazobactam were independent risk factors for vancomycin-associated nephrotoxicity (P = 0.027 and 0.017, respectively). Conclusions : We conclude that the nephrotoxicity risk of high-dose vancomycin in Japanese patients is not excessively high when administered within the confines of a therapeutic drug-monitoring program. However, special care must be taken with patients who are older or on concurrent piperacillin/tazobactam therapy.

Voxel-based morphometry of the marmoset brain: In vivo detection of volume loss in the substantia nigra of the MPTP-treated Parkinson's disease model.

Movement dysfunction in Parkinson's disease (PD) is caused by the degeneration of dopaminergic (DA) neurons in the substantia nigra (SN). Here, we established a method for voxel-based morphometry (VBM) and automatic tissue segmentation of the marmoset monkey brain using a 7-T animal scanner and applied the method to assess DA degeneration in a PD model, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated animals, with tyrosine-hydroxylase staining. The most significant decreases of local tissue volume were detected in the bilateral SN of MPTP-treated marmoset brains (-53.0% in right and -46.5% in left) and corresponded with the location of DA neurodegeneration found in histology (-65.4% in right). In addition to the SN, the decreases were also confirmed in the locus coeruleus, and lateral hypothalamus. VBM using 7-T MRI was effective in detecting volume loss in the SN of the PD-model marmoset. This study provides a potential basis for the application of VBM with ultra-high field MRI in the clinical diagnosis of PD. The developed method may also offer value in automatic whole-brain evaluation of structural changes for the marmoset monkey.

Involvement of LPA1 receptor signaling in cerebral ischemia-induced neuropathic pain.

We demonstrated previously that the lysophosphatidic acid-1 (LPA1) receptor plays a crucial role in the initiation of peripheral nerve injury-induced neuropathic pain through the alternation of pain-related genes/proteins expression and demyelination. The present study revealed that mild cerebral ischemia by left transient middle cerebral artery occlusion (tMCAO) for 15min causes the hypersensitive responses (paw withdrawal) to the nociception by electrical stimuli to the paw by the use of Neurometer Current Perception Threshold/C (CPT/C). The hypersensitivity or neuropathic pain was only observed by the stimulation with 250 and 2000, but not 5Hz, which are the characterized sine-wave frequencies of Aδ-, Aß- or C-fibers, respectively. The significant neuropathic pain was observed from day 2 through week 2 on the right paw after tMCAO, while there was slight but significant pain sensitivity on the left paw at day 7. The neuropathic pain on the contralateral side at week 2 after tMCAO was completely abolished in LPA1(-/-) mice. These results suggest that LPA1 receptor signaling plays key roles in the development of central neuropathic pain following cerebral ischemia as well as the peripheral neuropathic pain following partial sciatic nerve injury.

Immunophenotypical characterization of macrophages in rat bleomycin-induced scleroderma.

Scleroderma is a skin disorder characterized by persistent fibrosis. Macrophage properties influencing cutaneous fibrogenesis remain to be fully elucidated. In this rat (F344 rats) model of scleroderma, at 1, 2, 3, and 4 weeks after initiation of daily subcutaneous injections of bleomycin (BLM; 100 µl of 1 mg/ml daily), skin samples were collected for histological and immunohistochemical evaluations. Immunohistochemically, the numbers of cells reacting to ED1 (anti-CD68; phagocytic activity) and ED2 (anti-CD163; inflammatory factor production) began to increase at week 1, peaked at week 2, and decreased thereafter. In contrast, the increased number of cells reacting to OX6 (anti-MHC class II molecules) was seen from week 2 and remained elevated until week 4. α-Smooth muscle actin-positive myofibroblasts were increased for 4 weeks. Double labeling revealed that galectin-3, a regulator of fibrogenic factor TGF-ß1, was expressed in CD68+, CD163+, and MHC class II+ macrophages and myofibroblasts. mRNA expression of TGF-ß1, as well as MCP-1 and CSF-1 (both macrophage function modulators), were significantly elevated at weeks 1 to 4. This study shows that the increased number of macrophages with heterogeneous immunophenotypes, which might be induced by MCP-1 and CSF-1, could participate in the sclerotic lesion formation, presumably through increased fibrogenic factors such as galectin-3 and TGF-ß1; the data may provide useful information to understand the pathogenesis of the human scleroderma condition.

Evaluation of a simple loop-mediated isothermal amplification test kit for the diagnosis of tuberculosis.

OBJECTIVE: A new loop-mediated isothermal amplification (LAMP) test kit, including a simple DNA extraction device for the detection of Mycobacterium tuberculosis complex, was developed for commercial use and evaluated for its usefulness in diagnosing tuberculosis (TB). DESIGN: The LAMP test was performed using untreated and N-acetyl-L-cysteine (NALC) NaOH-treated sputum specimen. The efficiency of the kit was compared with other conventional laboratory examinations, including other nucleic acid amplification (NAA) tests. RESULTS: The sensitivity of LAMP using raw sputum (direct LAMP) in smear- and culture-positive specimens was 98.2% (95%CI 94.9-99.4), while the sensitivity in smear-negative, culture-positive specimens was 55.6% (95%CI 43.4-68.0). The diagnostic sensitivity of direct LAMP for the diagnosis of individuals with TB was 88.2% (95%CI 81.4-92.7). The sensitivity values of direct LAMP were slightly, but not statistically significantly lower than those of Cobas Amplicor MTB and TRC Rapid MTB, while the sensitivity of the LAMP test using NALC-NaOH treated sputum was significantly lower than other NAA tests (P < 0.05) for smear-negative, culture-positive specimens. The new commercial version of the LAMP kit was easy to handle and yielded results within 1 h of receiving sputum specimens. CONCLUSIONS: This test is considered a promising diagnostic tool for TB, even for peripheral laboratories with limited equipment, such as those in developing countries.

Inelastic collisional effect on a dilute granular shock layer with a heated wall.

The inelastic collisional effect on a shock layer of a dilute granular gas with a heated wall is numerically studied. To investigate the inelastic collisional effect via the gain term in the inelastic Boltzmann equation on the shock layer, an inelastic Bhatnagar-Gross-Krook (BGK) type equation, whose loss term is equivalent to that in the inelastic Boltzmann equation, is formulated on the basis of the kinetic theory of the granular gas. The inelastic BGK-type equation formulated for a hard-sphere particle is generalized to that for an inverse power law (IPL) molecule. Numerical results in a weakly inelastic regime confirm the nonequilirium contribution to the cooling rate, when the collision frequency depends on the particle velocity. The profile of the negative high-velocity tail of the distribution function in the generation regime of the shock wave obtained by the Direct Simulation Monte Carlo method is higher than that obtained by the proposed BGK-type equation when the collision frequency depends on the particle velocity because of the inelastic collisional effect via the gain term in the inelastic Boltzmann equation, which is not included in the proposed BGK-type equation.

The Bispectral Index Scale: its use in the detection of brain death.

OBJECTIVE: To evaluate the Bispectral Index Scale (BIS) monitor as a method of brain death (BD) detection. PATIENTS AND METHODS: We performed an observational prospective study in an intensive care unit (ICU) of a university hospital of 19 patients hospitalized nonconsecutively in the ICU with serious neurologic pathology and evolution toward BD. A BIS monitor, XP model, and the sensor "BIS Quatro" were used to continuously record values: suppression ratio (SR), quality of the signal index, and electromyographic (EMG) activity. RESULTS: The BD diagnosis was made through neurological clinical exploration and electroencephalogram (EEG) in all the cases. Additionally, transcranial Doppler was used in 13 patients. Coincident with clinical worsening, it was observed that there was a gradual decrease of the BIS value, together with a rise in the SR. In all the patients in which the BD diagnosis was confirmed, the BIS showed values of 0 and suppression rates of 100. Only one patient showed interferences, due to EMG activity, the same problem was detected when a conventional EEG was performing. After using a neuromuscular blocker, the values of BIS and SR were 0 and 100, respectively. CONCLUSIONS: The BIS is a noninvasive, simple, and easy to interpret method. All the patients with BD diagnosis except for one had a BIS value of 0 and TS of 100, showing a perfect correlation with the other diagnostic methods. The BIS cannot be used on its own for the confirmation of the BD, but it is a useful tool to detect the beginning of brain herniation.

Sast124, a novel splice variant of syntrophin-associated serine/threonine kinase (SAST), is specifically localized in the restricted brain regions.

Syntrophin is an adaptor protein that binds signaling molecules to the dystrophin-associated protein complex, which connects extracellular matrix to intracellular cytoskeleton for construction and maintenance of the postsynaptic structures in the neuromuscular junction and the CNS. Among these signaling molecules, a family of microtubule-associated serine/threonine kinases has a unique structural feature with a serine/threonine kinase domain and a postsynaptic density protein-95/discs large/zona occludens-1 domain. In the present study, we identified syntrophin-associated serine/threonine kinase-124, a novel splice variant of the syntrophin-associated serine/threonine kinase which is a member of the microtubule-associated serine/threonine kinases family. Comparing to the original clone (syntrophin-associated serine/threonine kinase-170), syntrophin-associated serine/threonine kinase-124 is truncated just downstream of the postsynaptic density protein-95/discs large/zona occludens-1 domain. Using a monoclonal antibody specifically recognizing syntrophin-associated serine/threonine kinase-124, strong expression of the protein was observed in neurons of the subventricular zone and granule cells of the olfactory bulb, Islands of Calleja, hippocampal dentate gyrus and cerebellum. syntrophin-associated serine/threonine kinase-124 is selectively localized in the nuclei of neurons and distinct from syntrophin-associated serine/threonine kinase-170, which is interacting with syntrophin on the cell surface. Considering the tissue and subcellular distributions of syntrophin-associated serine/threonine kinase-124, it is suggested that syntrophin-associated serine/threonine kinase-124 may have functions in transcriptional regulation for the features commonly shared by these neurons. On the other hand, syntrophin-associated serine/threonine kinase-124 was also localized in glia-like cell bodies in the corpus callosum and fiber bundles in the spinal trigeminal and solitary tracts, suggesting syntrophin-associated serine/threonine kinase-124 may have other functions in these types of cells.

Effects of cigarette smoke exposure on the ultrastructure of the golden hamster parathyroid gland.

Cigarette smoking has been identified as one of the risk factors to induce osteoporosis. However, we find no study on the morphology of the parathyroid gland under smoking exposure. We studied the ultrastructure of the parathyroid gland, lung and femur of the golden hamster exposed to cigarette smoke. Four-week-old male hamsters were housed in a plastic case (48x31x30 cm) and were exposed to cigarette smoke for 12 weeks, 5 minutes exposure, 4 times a day, 4 days a week. There were no differences in serum calcium level and the whole bone mineral density between the control and the smoke-exposed groups. In the parathyroid gland of the smoke-exposed animals, the Golgi complexes associated with many prosecretory granules were well developed and many secretory granules were located near the plasma membrane. Large lipid-like inclusion bodies were observed in the alveolar macrophages of the smoke-exposed animals. The femur morphology showed a wider area of resorbing surface in the smoke-exposed group than in the control group. From these findings, it is conceivable that the secretory activity of the parathyroid gland was stimulated with cigarette smoke exposure.

Effects of ethanol on the ultrastructure of the hamster femur.

Several previous studies have indicated that chronic ingestion of ethanol exerts harmful effects on bones. However, few data are available concerning the effects of ethanol on the ultrastructure of bone. To further elucidate the effects of ethanol on bone, we studied the morphology of femur in golden hamsters after long-term treatment with ethanol. Six-week-old male hamsters were divided into 4 groups. Ethanol-treated animals were given ethanol at a concentration of 7% with food and water freely available, whereas the pair-fed animals (weight-matched to ethanol hamsters) had tap water available as the only drinking fluid. The femur weight, blood ethanol and serum calcium concentrations were determined after 3 and 5 months. The bone mineral density (BMD) of the whole body was measured before and after the experiment. Femurs of both sides were dissected and processed for morphometric measurement, light microscopy, scanning and transmission electron microscopy. In the ethanol-treated hamsters, BMD of the whole body and the weight of femur tended to decrease when compared with those of the controls. Light microscopy and scanning electron microscopy showed that the trabecula in the distal end of the femur from ethanol-treated hamsters were thinner than those of the controls. We also observed the disrupted swollen mitochondria of the femoral osteoblasts and osteocytes in the ethanol-treated hamsters. No significant difference in serum calcium levels and femoral osteoclasts was found. These results indicate that long-term treatment with ethanol results in disruption of femoral osteoblasts and reduction of bone mass in trabecular bone.

Morphological identification of the lipid-storing cells in golden hamster parathyroid glands after vitamin A treatment.

We investigated hamster parathyroid glands of different ages using electron microscopy and found a new cell type in young, adult and senile hamsters. Theses special cells were located in interstitial tissues and invariably contained several lipid droplets within the cytoplasm. The cells showed an elongated spindle with some cell processes. The cells contained small Golgi complexes and moderate cisternae of the granular endoplasmic reticulum. The morphological characteristics of these cells were mostly the same as those of lipid-storing cells in other organs (Yamada and Hirosawa, 1976). After vitamin A administration, the lipid droplets in these cells markedly increased in number and also in volume density. The other morphological features of these cells resembled those of the control animals. We called these cells parathyroid lipid-storing cells. They may incorporate and store vitamin A within the lipid droplets. They can be classified as one of the cellular components in hamster parathyroid gland.

Characterization of the apoptosis-associated tyrosine kinase (AATYK) expressed in the CNS.

We isolated three related cDNA clones from a mouse cerebellar library; the type I cDNA was identical to the gene encoding the apoptosis-associated tyrosine kinase (AATYK), whose expression in myeloid precursor cells is increased during growth arrest or apoptosis. Low levels of AATYK mRNA expression were seen in adult mouse brains but not in embryos. In situ hybridization confirmed the widespread expression of AATYK mRNA in neurons throughout the adult brain. AATYK possessed tyrosine kinase activity and was autophosphorylated when expressed in 293 cells. AATYK mRNA expression was rapidly induced in cultured cerebellar granule cells during apoptosis induced by a low concentration of KCl (5 mM). Levels of endogenous AATYK protein were increased only slightly, but they were accompanied by an increase in molecular weight during apoptosis. Results of the tyrosine phosphatase treatments indicated that the increase in molecular weight was partly caused by tyrosine phosphorylation. The number of apoptotic granule cells overexpressing wild-type AATYK protein was significantly greater than the number of apoptotic granule cells overexpressing a mutant AATYK that lacked tyrosine kinase activity in low concentrations of KCl. These findings suggest that through its tyrosine kinase activity, AATYK is involved in the apoptosis of mature neurons.

Dynamic changes in glucose metabolism accompanying the expression of the neural phenotype after differentiation in PC12 cells.

To assess what properties of glucose metabolism are most closely related to expression of the neural phenotype, some parameters of glucose metabolism in PC12 cells before (tumor-type) and after differentiation (neuron-type) were investigated. Neuron-type cells exhibited a 2.7-fold higher level of [3H]DG retention than tumor-type cells, accompanied by a higher glucose transport rate and higher levels of hexokinase activity. [14C]CO2 production from [U-14C]glucose in neuron-type was also more than four-times greater than that in tumor-type cells. The levels of [14C]carbon in macromolecules from [14C]glucose in neuron-type cells were also much higher (10.6-fold) than those in tumor-type cells, and the levels of incorporation of [14C]carbon were almost as high as those of [14C]CO2. From the metabolite analysis, amino acids appeared to be the major compounds converted from glucose. On the other hand, the uptakes of [35S]methionine-[35S]cysteine and [3H]uridine in neuron-type cells were lower than those in tumor-type cells. Following depolarization with 50 mM potassium, [14C]CO2 production increased, but the retention of [14C]carbon was not changed in neuron-type cells. The largest change accompanied by acquisition of the neural phenotype was carbon incorporation into the macromolecules derived from glucose. This property may be important for the expression of the neural phenotype as well as the higher levels of both glucose uptake and oxygen consumption.

[The amount of the loss of cyclosporine A dose correlated with the amount of leaching di (2-ethylhexyl) phthalate from polyvinyl chloride infusion tube].

An interaction between cyclosporine A (CyA) injection and infusion tubes were examined. We used polyvinyl chloride (PVC) and polybutadiene (PB) tubes. CyA injection (Sandimmun) was diluted (0.495 mg CyA/ml) with saline and dripped through infusion tubes. The amounts of unsolved substances, loss of CyA dose and leached di (2-ethylhexyl) phthalate (DEHP) during the drip study were compared. CyA was not lost into the PB tube and no DEHP was leached. Therefore, using PVC tube, 11.9 mg of CyA were lost with in 24 h after the beginning of the administration, and the concentration of leached DEHP amounted to 93.6 micrograms/ml at 12 h. We also investigated the effects of the component of the einfusion solution on the loss of CyA into PVC tube using saline, electrolyte maintenance solution, 5% glucose and 10% maltose. Sugar-containing solutions were found to have less effects than other solutions on the loss of CyA dose and DEHP leaching. The leaching of DEHP may be a major factor for the generation of unsolved substances and the loss of CyA dose. In the clinical use of CyA injection, PB tube is the best selection and the sugar-containing solution is a second selection when PB infusion tubes are hard to obtain.

The untranslated region of (mu)-opioid receptor mRNA contributes to reduced opioid sensitivity in CXBK mice.

It is well known that there are individual differences in a sensitivity to analgesics. Several lines of evidence have suggested that the level of opioid-induced analgesia is dependent on the level of expression of the mu-opioid receptor (mu-OR). However, the molecular mechanisms underlying the diversity of the level of the opioid receptor and the opioid sensitivity among individuals remain to be elucidated. In the present study, we analyzed the opioid-receptor genes of CXBK recombinant-inbred mice, which show reduced sensitivity to opioids. Northern blotting, nucleotide sequencing, and in situ hybridization histochemical analyses demonstrated that CXBK mice possessed mu-OR mRNA with a normal coding region but an abnormally long untranslated region (UTR). In addition, the mu-OR mRNA level in CXBK mice was less than in the control mice. Next, we produced littermate mice that had inherited two copies of the wild-type mu-OR gene, had inherited two copies of the CXBK mu-OR gene, and had inherited both copies of the mu-OR genes. In these mice, inheritance of the CXBK mu-OR gene was well correlated with less mu-OR mRNA and reduced opioid effects on nociception and locomotor activity. We conclude that the CXBK mu-OR gene is responsible for the CXBK phenotypes. Because UTR differences are known to affect the level of the corresponding mRNA and protein and because UTRs are more divergent among individuals than coding regions, the present findings suggest that opioid sensitivity may vary, depending on different mu-OR levels attributable to divergent UTR of mu-OR mRNA.

A case of left inferior vena cava.

A case of left inferior vena cava (IVC) was found in a 72-year-old male cadaver during student dissection practice in 1999 at Gifu University School of Medicine. It was formed by junction of the left and right common iliac veins at the lower left corner of the 5th lumbar vertebra. This IVC (15-mm caliber) ascended 82 mm along the left side of the abdominal aorta dorsally to the ureter. Receiving the left renal vein, it became 21 mm in caliber and ran obliquely upward for 43 mm across the abdominal aorta. As soon as it received two right renal veins at the level of the 2nd lumbar vertebra, the IVC (25-mm caliber) turned directly above. The present case belongs to Type C of the classification of McClure and Butler (1925), which is based on the combinations of the left and right IVCs, and on their location relative to the ureters. The present case also belongs to Type 1 of the classification of Yoshida et al. (1981). We consider that left IVC in the present case is mainly caused by disappearance of the right supracardinal vein and persistence of the left one during the embryological development of the IVC.

Greater resistance and lower contribution of free radicals to hypoxic neurotoxicity in immature rat brain compared to adult brain as revealed by dynamic changes in glucose metabolism.

Seven-day-old rat brain slices were incubated at 36C in oxygenated Krebs-Ringer solution containing [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG), and serial two-dimensional time-resolved images of [(18)F]FDG uptake by the slices were obtained. The Gjedde-Patlak graphical method was applied to the image data, and the duration limit of hypoxia loading that allowed recovery of the fractional rate constant (k3*) of [(18)F]FDG (proportional to the cerebral glucose metabolic rate) after hypoxia loading to the unloaded control level was 50 min, and MK-801 as an N-methyl-D-aspartate antagonist had neuroprotective effects, but PBN as a free radical scavenger was ineffective. In our previous study in adult (7-week-old) rat brains [Murata et al., Exp Neurol 2000, 164:269-279], the limit of the hypoxia loading time was 20 min, and both MK-801 and PBN were effective. In the immature rat brains, the ratio of aerobic glucose metabolism to the total glucose metabolism was low compared with the adult rat brains, suggesting only a slight involvement of free radicals in hypoxic neurotoxicity. These data suggest that the higher resistance of immature brains to hypoxia compared to that of adult brains is attributable to a lower involvement of free radicals due to a lower aerobic glucose metabolic rate.

Effect of low calcium diet on the ultrastructure of the rat parathyroid gland.

Young female rats were fed with normal (1.18%) or low (0.05%) calcium diet for 3, 7, 15 or 30 days. The morphology of the parathyroid glands was studied together with serum calcium, parathyroid hormone (PTH), calcitonin and bone mineral density (BMD). As compared to the animals fed with the normal calcium diet, BMD of whole body of the rats fed with the low calcium diet was significantly decreased, whereas the serum PTH level was increased. The parathyroid glands in the rats fed with the low calcium diet were markedly enlarged. In the parathyroid chief cells of the rats fed with the low calcium diet, the Golgi complexes and the cisternae of the granular endoplasmic reticulum were well developed, while the large granules and large vacuolar bodies decreased. Some secretory granules located near the plasma membrane. A proportionally larger increase of the cytoplasm was estimated in the rats fed with the low calcium diet for three and seven days. Enlargement of the cytoplasm and rather frequent mitoses of the chief cells were observed in the rats fed with the low calcium diet for 15 and 30 days. These findings suggest that the rapid bone loss in young rats induced by the low calcium diet is essentially due to stimulated activity of the parathyroid gland. The stimulated gland may be a result of hypertrophy at the early stage and a combination of hypertrophy and hyperplasia at the later stage of calcium deficiency.