Renal handling of carnitine in children with carnitine deficiency and hyperammonemia associated with valproate therapy

Free and acylcarnitine in serum and urine samples were measured in five patients with hyperammonemia associated with anticonvulsant therapy including sodium valproate, of whom three had a Reye-like syndrome. All had considerable reduction in serum free carnitine and slight increase of acylcarnitine concentrations, suggesting increased conversion of free to acylcarnitine by valproate administration. Urinary excretion of both free and acylcarnitine was increased, accompanied by depressed reabsorption of free carnitine and decreased acylcarnitine/free carnitine clearance ratio. These results indicate a decreased threshold for free carnitine. The combination of these several factors may be responsible for carnitine deficiency in patients with hyperammonemia taking valproate.     

Successful laparoscopic fundoplication in children with ventriculoperitoneal shunts

We reported successful laparoscopic fundoplication in 2 pediatric cases with VPS and discuss the safety and feasibility of the procedure. Case 1: A 13-year-old girl with VPS underwent laparoscopic fundoplication. Case 2: a 9-year-old boy with VPS underwent laparoscopic fundoplication. In both cases, laparoscopic Nissen fundoplication was performed with a standard five-port technique with a low pressure of a pneumoperitoneum. The VPS system had no effect on port layout and intraabdominal manipulation and no adverse complications were observed in either case. The effect of a pneumoperitoneum in the VPS system remains controversial, however, the author emphasized that advanced laparoscopic surgery can be performed safely with creating a low pressure of a pneumoperitoneum.     

Effect of grapefruit pulp on the pharmacokinetics of the dihydropyridine calcium antagonists nifedipine and nisoldipine

The effect of the intake of 200 g of grapefruit pulp (corresponding to one grapefruit) on the pharmacokinetics of the calcium antagonists nifedipine (NF) and nisoldipine (NS) were investigated in 8 healthy Japanese male volunteers. A crossover design was used for the study: group I did not ingest any grapefruit (control group); group II ingested grapefruit 1 h after drug administration; and group III ingested grapefruit 1 h before drug administration. The intake of grapefruit pulp increased the plasma concentrations of both NF and NS, an effect that has previously been reported with grapefruit juice. The increase was most marked when grapefruit was eaten before drug administration. For both NF and NS, subjects who ingested grapefruit 1 h before drug administration exhibited a greater Cmax and AUC0-24 than did subjects in the control group. For NF, the Cmax was 1.4 times higher and the AUC0-24 1.3 times larger in group III than in group I. For NS, the Cmax was 1.5 times higher and the AUC0-24 1.3 times larger in group III than in group I. The increase in the AUC0-24 was significant for both drugs (p < 0.05). The finding that the ratios of Cmax and AUC0-24 for unchanged drug and metabolites did not vary greatly among the three groups for either drug suggests that the increase in serum concentration produced by grapefruit intake may be due to other factors than an inhibitory effect on drug metabolism. Also, the increases in Cmax and AUC0-24 of NS produced by grapefruit intake were smaller than those produced by grapefruit juice intake, indicating that grapefruit pulp and juice have different effects on the pharmacokinetics.     

Chronic cerebral hypoperfusion induces white matter lesions and loss of oligodendroglia with DNA fragmentation in the rat

Cerebrovascular white matter lesions represent an age-related neurodegenerative condition that appears as a hyperintense signal on magnetic resonance images. These lesions are frequently observed in aging, hypertension and cerebrovascular disease, and are responsible for cognitive decline and gait disorders in the elderly population. In humans, cerebrovascular white matter lesions are accompanied by apoptosis of oligodendroglia, and have been thought to be caused by chronic cerebral ischemia. In the present study, we tested whether chronic cerebral hypoperfusion induces white matter lesions and apoptosis of oligodendroglia in the rat. Doppler flow meter analysis revealed an immediate reduction of cerebral blood flow ranging from 30% to 40% of that before operation; this remained at 52–64% between 7 and 30 days after operation. Transferrin-immunoreactive oligodendroglia decreased in number and the myelin became degenerated in the medial corpus callosum at 7 days and thereafter. Using the TUNEL method, the number of cells showing DNA fragmentation increased three- to eightfold between 3 and 30 days post-surgery compared to sham-operated animals. Double labeling with TUNEL and immunohistochemistry for markers of either astroglia or oligodendroglia showed that DNA fragmentation occurred in both of these glia. Messenger RNA for caspase-3 increased approximately twofold versus the sham-operated rats between 1 and 30 days post-surgery. Immunohistochemistry revealed up-regulation of caspase-3 in the oligodendroglia of the white matter, and also in the astroglia and neurons of the gray matter. Molecules involved in apoptotic signaling such as TNF- and Bax were also up-regulated in glial cells. These results indicate that chronic cerebral hypoperfusion induces white matter degeneration in association with DNA fragmentation in oligodendroglia.     

Apoptosis and microglial activation in influenza encephalopathy

During influenza epidemics in Japan, the number of children with acute encephalopathies and encephalitis has recently increased. Although the pathophysiologies remain unclear, there is usually brain edema with evidence of damage to the blood-brain-barrier (BBB). We investigated the glial reaction and apoptosis in brains of eight such cases comprising two of acute necrotizing encephalopathy and six of influenza encephalopathy, and compared the results with those in five control brains. Apoptosis, evidenced by chromatin condensation and fragmentation in hematoxylin sections, in situ end labeling of fragmented DNA (TUNEL) and DNA laddering, was observed in neurons and glial cells in four brains with influenza encephalopathy. In the TUNEL-positive brains, the increase in microglia was greater than in the TUNEL-negative brains. Immunoreactivity for active-caspase 3, demonstrated by immunohistochemistry, and the overexpression of a caspase-cleaved fragment of poly(ADP-ribose) polymerase, demonstrated by Western blotting, indicated that activation of caspase 3 is involved in the apoptotic pathway in the brains of influenza encephalopathy cases. Apoptosis or specific pathological processes that cause apoptosis may give rise to aggravated encephalopathy.     

Resolution of a leg ulcer after hysterectomy for huge uterine myoma

Venous ulcers are the most common type of leg ulcers, accounting for 80% to 90% of cases. We report a large, therapy-resistant ulcer present for three months on the right leg of a 44-year-old woman who also had a huge uterine myoma. Without any other treatment, the leg ulcer regressed spontaneously three months after a hysterectomy for the uterine myoma that had been demonstrated in a CT image to be compressing the right common iliac vein in the pelvis. Uterine myoma can become the cause of venous insufficiency of the leg, when it is big enough to disturb the blood circulation in the pelvis in individuals who have incompetent perforating veins.     

Difference in the metabolism of vitamin K between liver and bone in vitamin K-deficient rats

The difference between vitamin K metabolism in the liver and that in the bone of vitamin K-deficient rats was examined. After 17 d administration of vitamin K-deficient food, vitamin K in the liver was almost depleted, and prothrombin time (PT) was prolonged. Serum total osteocalcin level was slightly decreased by vitamin K deficiency, whereas serum undercarboxylated osteocalcin level did not change. The level of menaquinone (MK)-4 as well as that of phylloquinone was decreased, but approximately 40 % of the initial level still existed in the femur after the 17 d period. A single-dose administration of vitamin K (250 nmol/kg body weight) markedly increased vitamin K level in the liver but not in the femur. These results suggest that the turnover of vitamin K in the bone is slower than that in the liver, and bone metabolism may be little affected by the short period of intake of vitamin K-deficient food. However, intake of a larger amount of vitamin K is required for its accumulation in the bone than in the liver. Furthermore, the counteracting effect of MK-7 on prolonged PT in vitamin K-deficient rats was found to be higher than phylloquinone or MK-4.     

Pseudoxanthoma elasticum: report of a case without any mutations in 5 exons of the MRP6 gene

Pseudoxanthoma elasticum (PXE) is an inherited systemic disorder of connective tissue. We describe a patient with PXE who does not have mutations in exons 16, 24, 27, 28, and 30 of the MRP6 gene.     

A comparative study on the expression of cyclooxygenase and 5-lipoxygenase during cerebral ischemia in humans

Prostaglandins and leukotrienes (eicosanoids), metabolites of the arachidonic acid pathway, are subjected to altered synthesis or relocation after an ischemic insult. Although cyclooxygenase (COX) expression has been reported in human cerebral ischemia, no information is available on the expression of 5-lipoxygenase (5-LO) and its topographical correlation to COX induction. The objective of this study was to elucidate the comparative distribution of eicosanoids in ischemic tissues. COX and 5- LO, key enzymes for the synthesis of prostaglandins and leukotrienes, respectively, were examined in autopsied brains. COX1 was expressed intensely in the microglia but weakly in the neurons in control brains. These COX1-immunoreactive microglia showed a more activated form following ischemic damage and hypoxemia. In contrast, COX2 was absent in the control brains, and was induced robustly in the neuronal cell bodies and dendrites during the acute stages of focal ischemic damage, and then subsided at the subacute stages. These COX2-immunoreactive neurons accumulated in the peri-infarct regions, but were absent from the distant regions. In focal ischemic damage and Binswanger's disease, COX2 was up-regulated in the microglia. Neuronal immunostaining for 5-LO was up-regulated occasionally during hypoxemia and focal ischemic damage. Glial cells immunoreactive for 5-LO appeared in the foci of the ischemic damage, with small blood vessels being infiltrated by 5-LO-immunoreactive mononuclear leukocytes. These findings indicate that the isozymes of COX are differentially regulated depending on the cellular source and the types of ischemic damage, and that vascular 5-LO may accelerate the migration of leukocytes and augment the blood-brain barrier permeability. The possibility of increased substrate availability for the other should be noticed in specific inhibition of either COX or 5-LO since these two enzymes are accumulated in parallel in ischemic tissues.