CYP2E1 and ALDH2 Genotypes and Alcohol Dependence in Japanese

The genotypes of the CYP2E1 and ALDH2 loci of alcoholic (alcohol dependence) and nonalcoholic (healthy) Japanese were investigated to examine the relationship between the polymorphism of CYP2E1 (C₁/C₂) and ALDH2 ( ALDH2*1/ALDH2*2 ), and the susceptibility to alcoholism. There was no significant difference in C₂ gene frequency between alcoholics (0.19) and nonalcoholics (controls) (0.20), whereas there was a significant difference in ALDH2 allele frequency, suggesting that, in Japanese, the C₂ genotype of CYP2E1 may have nothing to do with the risk of developing alcohol dependence. However, the ALDH2*1 allele may influence drinking behavior and the development of alcohol dependence. Furthermore, racial interethnic differences in the frequency of the mutated allele of the CYP2E1 gene (CJ were found, like the ALDH2 gene. Japanese healthy controls showed a significantly higher frequency of the C₂ allele than did Swedish healthy controls (0.05; reported by Persson et al., FEBS Lett. 319:207-211,1993).     

Cytochrome P-45011 beta in rat brain

The presence of cytochrome P-45011 beta in rat brain was studied by immunohistochemistry using polyclonal rabbit antibodies raised against purified bovine adrenocortical P-45011 beta, which is involved in the steroid 11 beta-hydroxylation and glucocorticoid formation. The results showed that cytochrome P-45011 beta immunoreactivity is selectively localized to the tracts of myelinated fibers throughout the brain. The specificity of immunohistochemical stainings with P-45011 beta antibodies was established by control tests including nonimmune rabbit immunoglobulin Gs and P-45011 beta antibodies absorbed with purified antigen. Western immunoblots of homogenates from different brain areas with P-45011 beta antibodies, together with biochemical enzymatic assays for cytochrome P-45011 beta monooxygenase activity in these homogenates, confirmed the selective localization of this enzyme observed with immunohistochemistry. Cytochrome P-45011 beta and 11 beta-hydroxylase activity were detected in a homogenate from the cortical white matter (brain area rich in myelinated fibers) as in that from the rat adrenal, but were not detectable in a homogenate from the cerebral cortex (brain area poor in myelinated fibers). Furthermore, quantitation of the P-45011 beta bands on the immunoblots by the areal density revealed that the cortical white matter contains approximately 1.4 pmol of cytochrome P-45011 beta/mg of tissue protein, the value of which was about one sixth of the corresponding value estimated in the rat adrenal. This relatively high content of cytochrome P-45011 beta was also reflected in a relatively high level of 11 beta-hydroxylase activity measured in a homogenate of this brain area by biochemical enzymatic assays using [4-14C]-11-deoxycorticosterone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamic effects of KRN2391 (potassium channel opener) in halothane-anesthetized dogs

The cardiovascular responses to an infusion of KRN2391, a potassium channel opener, was studied in halothane-anesthetized dogs. Intravenous administration of KRN2391 at 1.0 and 5.0 μg·kg⁻¹·min⁻¹ for 60 min produced dose-dependent decreases in mean arterial pressure (MAP) and systemic vascular resistance (SVR) associated with dose-dependent increases in the cardiac index (CI) and stroke volume index (SVI) but was not accompanied by an increase in heart rate (HR). The maximum decrease in MAP during the infusion of KRN2391 at 1.0 and 5.0 μg·kg⁻¹·min⁻¹ was −13±7% (P<0.01) and −37±10% (P<0.01), respectively. The maximum reduction in SVR after 1.0 and 5.0 μg·kg⁻¹·min⁻¹ was −20±11% (P<0.01) and −60±16% (P<0.01), respectively. A KRN2391 infusion of 1.0 and 5.0 μg·kg⁻¹·min⁻¹ increased Cl a maximum of 11±13% (P<0.05) and 65±33% (P<0.01), respectively. KRN2391 1.0 μg·kg⁻¹·min⁻¹ showed a tendency to increase SVI but this change was not significant, KRN2391 5.0 μg·kg⁻¹·min⁻¹, however, produced a significant increase in SVI. The present results demonstrate that the decrease in MAP and the increases in CI and SVI caused by KRN2391 are due to a reduction in the afterload. Therefore, we conclude that these cardiovascular profiles of KRN2391 may be benificial in perioperative uses including the control of systemic blood pressure and the treatment of hypertension during halothane anesthesia in clinical practice.     

Hypoxia‐inducible factor 1α may be a marker for vasculitic neuropathy

Neuromuscular biopsy is still an essential method for diagnosing vasculitic neuropathy, although its diagnostic sensitivity is at most 60%. Our objective was to examine the expression of hypoxia‐inducible factor 1α (HIF‐1α) in peripheral nerves and to evaluate its usefulness in diagnosing vasculitic neuropathy, especially for discrimination from other axonal neuropathies. Forty‐one patients with vasculitic neuropathy consisting of 20 definite, 14 probable and seven possible diagnoses, 15 patients with metabolic neuropathy, five with motor neuron disease and six with chronic inflammatory demyelinating polyneuropathy were included. Nerve biopsy specimens were immunohistochemically examined for HIF‐1α and various cell markers. Distinct immunoreactivity (IR) was observed in nuclei of endoneurial cells in 54% (22/41) of vasculitic patients, while specimens from metabolic neuropathies showed less nuclear IR and the difference of mean density of HIF‐1α‐positive nuclei was significant. Two patients with possible vasculitis who showed HIF‐1α‐positive nuclei in endoneurium, were later confirmed to have vasculitis by skin biopsies. Most of the cells expressing HIF were demonstrated to be Schwann cells. There was a trend in the vasculitic patients with early phase nerve damage to display higher endoneurial HIF‐1α‐IR. HIF‐1α may be an immunohistochemical marker for vasculitic neuropathy, especially when the observed section contains no vasculitic lesions.     

Chromosome analysis of brain tumors in childhood

We performed a chromosome analysis of 26 pediatric brain tumors, including 20 primitive neuroectodermal tumors (PNETs), 5 astrocytomas, and I immature teratoma. Specimens were treated with collagenase, placed in overnight or short-term cultures, and harvested for chromosome analysis. Numerical and/or structural abnormalities were noted in 14 of the 20 PNETs and 4 of the 5 astrocytomas. In 13 PNETs, so-called medulloblastoma in the cerebellum, an i(17q) was the most frequent structural abnormality, accounting for 30% (4/13). Double minute chromosomes (dmin) were observed in one tumor. Near-diploidy was demonstrated in three of these PNETs, hyperdiploidy in three, and near-tetraploidy in three. We could not find any correlation of these cytogenetic findings with the prognosis. In the remaining seven PNETs other than medulloblastoma, the karyotypes of five PNETs demonstrated a variety of numerical and structural abnormalities. As to the astrocytomas, losses of chromosomes 7 and 9 with dmin were observed in two, and structural abnormalities of chromosomes 1 and 17 were also observed in two tumors. In our limited cases, however, we could not find the same chromosome abnormalities that are well known in adult astrocytomas. A congenital immature teratoma showed hyperdiploidy with increased numbers of chromosomes 3, 6, and 12. We conclude that i(17_q) is an important chromosome abnormality in medulloblastomas, and that the oncogenesis of pediatric astrocytomas might be different cytogenetically from that of adult astrocytomas.     

The effect of prostacyclin (PGI) on denervated tissues--especially, about denervation supersensitivity]

It is well known that contractive agents of smooth muscle have denervation supersensitivity. But, the existence of denervation supersensitivity in relaxed ones does not become so clear. We investigated these supersensitivity, especially prostacyclin (PGI2). We made the denervated artery by lumbar sympathetic ganglionectomy in mongrel dogs. Namely, saphenous and dorsal pedal arteries were denervated by this ganglionectomy. And we studied the changes of these arterial tensions by magnus apparatus. Dose-response (D-R) curves of denervated arteries for KCl and noradrenaline (NE) shifted to left against control arteries. Next, we studied effects of PGI2. At first, we measured ED50 of KCl and NE contraction. And, we produced the half contraction on each artery by using ED50 of KCl and NE. Lastly, PGI2 was added on the half contractive arteries to study relaxed changes. D-R curves of denervated arteries for PGI2 shifted to left, too. These denervated arteries acquired the supersensitivity for PGI2. Clinically, if we use relaxants after organ transplantation, these drugs may be very effective for the perfusion of the grafts.     

Ectopic cervico-mediastinal thymoma confirmed by flow cytometric analysis of tumor-derived lymphocytes

Ectopic cervical or cervico-mediastinal thymomas are very rare and most of them are asymptomatic, except for the presence of a cervical mass. We present the case of a 71-year-old man with an ectopic cervico-mediastinal thymoma threatening superior vena cava syndrome. He had a slight headache and presented with venous dilatation on the chest wall. A computed tomographic scan and magnetic resonance, imaging of the chest demonstrated a mass extending from the right neck to the hilum, that indented the trachea and compressed and displaced the brachiocephalic veins anteriorly. Under a right hemicollar incision and median sternotomy, the mass was resected en bloc together with the thymus. The resected specimen was an encapsulated mass measuring 11×7×4 cm. The pathological diagnosis was type AB, non-invasive thymoma, confirmed by 3-color flow, cytometry of tumor-derived lymphocytes. Flow cytometry using biopsy material may contribute to the preoperative diagnosis of ectopic thymoma.     

KT5926, a potent and selective inhibitor of myosin light chain kinase

KT5926, (8R*,9S*,11S*)-(-)-9-hydroxy-9-methoxycarbonyl-8-methyl-14-n-propoxy-2,3 ,9, 10-tetrahydro-8,11-epoxy, 1H,8H, 11H-2,7b,11a-triazadibenzo[a,g]cycloocta[cde] trinden-1-one, was found to be a potent and selective inhibitor of myosin light chain kinase. The compound inhibited both Ca2+/calmodulin-dependent and -independent smooth muscle myosin light chain kinases to a similar extent. The inhibition was not affected by the concentration of calmodulin. Kinetic analyses showed that the mode of inhibition was of the competitive type with respect to ATP (Ki, 18 nM) and of the noncompetitive type with respect to myosin light chain (Ki, 12 nM). These results indicated that KT5926 directly interacted with the enzyme at the catalytic site. KT5926 also inhibited other protein kinases, but with relatively high Ki values; the values for protein kinase C, cAMP-dependent protein kinase, and cGMP-dependent protein kinase were 723, 1200, and 158 nM, respectively. Ca2(+)-ATPase, Na+/K(+)-ATPase, hexokinase, and 5'-nucleotidase were not inhibited by KT5926 at less than 10 microM. The effect of KT5926 on serotonin secretion and protein phosphorylation induced by platelet-activating factor or phorbol ester was examined in rabbit platelets. KT5926 inhibited the phosphorylation of a 20-kDa protein but had no effect on the phosphorylation of a 40-kDa protein, thereby indicating that the compound exerts its selective inhibition of myosin light chain kinase in intact cells. The compound inhibited serotonin secretion induced by platelet-activating factor, but its potency was significantly less than that of K-252a, (8R*,9S*,11S*)-(-)-9-hydroxy-9-methoxycarbonyl-8-methyl-2,3,9, 10-tetrahydro-8,11-epoxy-1H,8H,11H-2,7b, 11a-triazadibenzo[a,g]cycloocta [cde]trinden-1-one, which inhibited the phosphorylation of both the 20-kDa protein and the 40-kDa protein. Phorbol ester-induced secretion was not suppressed by KT5926. These results provide the evidence that both the 20-kDa protein phosphorylation by myosin light chain kinase and the 40-kDa protein phosphorylation by protein kinase C substantially contribute to the secretion response in platelets.     

Clinical and hemodynamic sequelae of mitral prostheses evaluated by Doppler echocardiography]

To determine the relative superiority of a prosthesis in the mitral position, in vivo hemodynamics were examined by Doppler echocardiography, and the results were compared with other types of mechanical mitral valves including 63 Bj?rk-Shiley convexo-concave (BS) values, 30 Duromedics (DM) valves, and 58 Medtronic Hall (MH) valves. For this comparison, the following indices were evaluated: peak velocity of mitral flow (PV), mitral valve orifice area (MVA), mitral valvular regurgitation, New York Heart Association (NYHA) classification, pulmonary capillary wedge pressure (PC), cardiac index (CI) and valve-related complications. On Doppler echocardiograms, PV ranged from 1.2 to 2.0 m/sec with a mean of 1.6 m/sec. There was no evident relationship between the PV and the valve size in each type of prosthesis, and no significant difference in the PVs among the valves. The mean MVA was 2.6 cm2 (25 mm DM, 25 mm MH), which was regarded satisfactory from a clinical standpoint. MVA increased with the increase in the valve size in all types of valves, and of all sizes, MVA was larger in the DM and MH groups than in the BS group. Similarly, the incidence of valvular regurgitation was relatively low in all groups, and the degree of regurgitation proved to be grade II or less in all cases. As for the clinical results, clinical symptoms (NYHA) and hemodynamic states (PC, CI) improved postoperatively, with the differences among the types of prosthetic valves being insignificant. The incidences of thromboembolism, valvular thrombosis, valve failure and prosthetic endocarditis were relatively low in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term survival after removal of a malignant peripheral nerve sheath tumor originating in the anterior mediastinum

Malignant peripheral nerve sheath tumors (MPNSTs; malignant schwannomas) rarely occur in the anterior mediastinum, and their prognosis is poor. A 75-year-old man was referred to our hospital for examination of an anterior mediastinal tumor. A computed tomography-guided percutaneous needle biopsy revealed only fibrosis. The tumor was completely excised via a median sternotomy with partial resection of the pericardium and right upper lobe of the lung. Thereafter, the tumor was diagnosed as a storiform-pleomorphic type of malignant fibrous histiocytoma. At 1 year after the surgery, a distant metastasis was found in the interlobular space between the right middle and lower lobes. The tumor was completely excised via a right posterolateral thoracotomy. Reexamination of the primary and secondary tumors revealed an MPNST. No recurrence was found up to 5 years after the second surgery without adjuvant chemotherapy or radiation therapy. However, he died from multiple lung metastases after 6 years.