ErbB inhibitors ameliorate behavioral impairments of an animal model for schizophrenia: implication of their dopamine-modulatory actions

Ligands for ErbB receptors, including epidermal growth factor (EGF) and neuregulin-1, have a neurotrophic activity on midbrain dopaminergic neurons and are implicated in the pathophysiology of schizophrenia. Although ErbB kinase inhibitors ameliorate behavioral deficits of the schizophrenia model that was established by hippocampal lesioning of rat pups, the antipsychotic action of ErbB kinase inhibitors and its general applicability to other models are not fully characterized. Using a different animal model, here, we examined whether and how ErbB kinase inhibitors ameliorate the behavioral endophenotypes relevant to schizophrenia. The animal model for schizophrenia was prepared by exposing neonatal rats to the cytokine EGF. Intraventricular infusion of the ErbB1 inhibitors ZD1839 and PD153035 in these animals ameliorated the deficits in startle response and prepulse inhibition in a dose-dependent manner. The deficits of latent inhibition of fear learning were also alleviated by ZD1839 with its limited effects on body weight gain or locomotor activity. ZD1839 infusion also decreased the busting activity of nigral dopamine (DA) neurons and reduced pallidal DA metabolism, a result that mimics the anti-dopaminergic profile of risperidone and haloperidol in this brain region. ErbB inhibitors appear to have anti-dopaminergic actions to alleviate some of the behavioral deficits common to animal models for schizophrenia.

[New method for preparing proximal anastomotic system]

Heartstring is a useful device. However, the device failure at the time of loading the seal into the delivery device is a troublesome issue. To avoid this problem, we invent a new method using 2 tourniquets made of 5 mm-wide woven Teflon tapes and plastic tubes. Using our method, the loading procedure became easier and more reliable.

[The efficacy of function water (electrolyzed strong acid solution) on open heart surgery; postoperative mediastinitis due to methicillin-resistant Staphylococcus aureus]

Methicillin-resistant Staphylococcus aureus (MRSA) infection after cardiac surgery has recently increased. We compared the anti-inflammatory effect of an electrolyzed strong acid solution and a warm saline solution in patients with open heart surgery. These solutions were used for mediastinal irrigation before closing the sternum. Group A patients were irrigated by a warm saline solution, and group B patients were irrigated by an electrolyzed strong acid solution, administration of this water is safe, feasible, and easy for the prevention of MRSA infection. Postoperative infection was significantly decreased in the group B as compared in the group A. An electrolyzed strong acid solution may be effective on postoperative infection, particularly MRSA infection following open heart surgery.

[Strategy for reducing mortality in the procedure of distal arch aneurysm]

We investigated various surgical procedure of distal arch aneurysm to propose a safer strategy with less mortality. From January 1998 to March 2001, we operated 10 cases of distal arch aneurysm. Different methods were applied over the years to reach the current improved technique, which is a combination of retro grade general perfusion, median sternotomy, deep hypothermic circulation arrest with selective cerebral perfusion, pharmacological cerebral protection, none touch aortic method, and open distal anastomosis. We have managed to improve postoperative complications, which we experienced many times in the past. We have had no post-operative cerebral accidents, except for 1 case of death by and mesenteric arterial obstruction due to leukemia. In conclusion, our method is safe and feasible and can expect the reduction of post-operative mortality.

[Lymphoscintigraphy for chylothorax after replacement of descending thoracic aortic aneurysm]

A 77-year-old female with Stanford B chronic aortic dissection, received elective replacement of descending aorta. The aorta distal to the aneurysm was encircled with a tape, and replaced using the double barrel technique. After the operation, chest X-ray showed effusion on the bilateral side. The amount of milky fluid from drain increased to 2,000 ml per day. The chemical profiles of the fluids were compatible with chylothorax. The Thoracic duct near the diaphragm was closed through left mini-thoracotomy. But the leakage of chyle did not cease. The lymphoscintigraphy showed a leakage to right lower intrathorax near the diaphragm and native aorta. A defect of the thoracic duct was closed, and chylothorax was cured. This case shows that though detailed anatomical structure of thoracic duct is not revealed, lymphoscintigraphy is useful for the localization of leakage in patients with chylothorax of post-cardiovascular-surgery.

[In vitro antibacterial activity of prulifloxacin, a new oral quinolone, and comparative susceptibility rate at clinical breakpoint MIC]

In vitro drug sensitivity of clinically isolated bacteria against prulifloxacin (PUFX), which is a new quinolone, was investigated, and the antibacterial activity and susceptibility rate at clinical breakpoint were compared with those of norfloxacin, ofloxacin (OFLX), ciprofloxacin, tosufloxacin, fleroxacin, sparfloxacin and levofloxacin (LVFX). The following results were obtained. 1) PUFX showed a broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria. 2) MIC80 of PUFX was 0.25 and 1 microgram/ml, against methicillin susceptible Staphylococcus aureus and Streptococcus pneumoniae, respectively and below 0.125 microgram/ml against Gram-negative Enterobacteriaceae. MIC90 of PUFX against Pseudomonas aeruginosa, which has MIC not exceeding 4 micrograms/ml to OFLX, was 0.5 microgram/ml. 3) PUFX was judged as active against the bacteria under the criteria proposed presented by "the Sensitivity Determination Committee for Antibiotics, Japan Society of Chemotherapy: Break Point for Respiratory Infectious Diseases and Sepsis". It is suggested that the sensitivity of each bacterial species to PUFX was high. 4) From the correlation analysis of MIC, PUFX was shown to have two to eight times higher antibacterial acitivity than LVFX for Citrobacter freundii, Serratia marcescens and Pseudomonas aeruginosa. 5) PUFX showed potent short-time bactericidal activity against S. aureus and P. aeruginosa.

Inhibition of cultured vascular smooth muscle cell migration by simvastatin (MK-733)

The effect of simvastatin (MK-733), a potent 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on the migration of cultured porcine smooth muscle cells (SMCs) was investigated in modified Boyden chambers. Platelet-derived growth factor (PDGF) stimulated the SMC migration dose dependently. MK-733 inhibited the migration response induced by PDGF with an IC50 value of 2 microM. Supplementation with mevalonate restored the migration response inhibited by MK-733 but the addition of low-density-lipoprotein (LDL) did not change the response. Another HMG-CoA reductase inhibitor, pravastatin (CS-514), also reduced the migration response. However its potency was far less than that of MK-733. MK-733 also inhibited the SMC migration stimulated by fibrinogen. These results suggest that non-sterol metabolite(s) of mevalonate, possibly prenylated proteins, are involved in a migration signaling pathway and that HMG-CoA reductase inhibitors are effective in the prevention of the formation of intimal hyperplasia in atherosclerosis.

Microtubular structures in a stable staphylococcal L-form

Microtubular structures, which were demonstrated as straight, dense-walled cylinders attached to cell membranes, were found in a stable staphylococcal L-form grown in the absence of antibiotic.

Studies on the minimum reproducible unit of staphylococcal L-forms

The minimum size of a reproducible unit of staphylococcal L-forms was determined by filtration and electron microscopic methods. Ultrathin sections of an induced strain of Staphylococcal L-forms (STA-EMT-1) in liquid medium revealed several types of structures, all of which were bound by a single membrane and most of which possessed ribosome-like granules. Many of the small granules were less than 0.3 micron and were attached to the membrane of the large bodies. Using a serial filtration method, it was observed that viable L-forms were still detected in 0.22 micron filtrate, but the viable cell count of L-forms decreased in number with the decrease in pore size of membrane filters. A fractionation technique, using L-forms filtered through a membrane filter with a 0.45 micron pore size, revealed that there were three classes of small bodies but only the first class with ribosome-like granules over approximately 0.2 micron in diameter seems to be able to reproduce.

Membrane structures in stable L-forms of Escherichia coli

Microtubular and lamellate membrane structures were observed at the log phase of growth in the stable L-forms of Escherichia coli cultured in the absence of penicillin.