Choice for response alternatives differing in reinforcement frequency in dopamine D2 receptor mutant and Swiss-Webster mice

Rationale

A previous study showed that dopamine (DA) D₂ receptors (D₂Rs) are involved in the reinforcing effectiveness of food, but the specific involvement of DA D₂Rs in choice among food reinforcers remains unclear.

Objectives

The current study used genetic and pharmacological approaches to assess the role of D₂Rs in choice among food-reinforcement frequencies using the generalized matching law (GML), which specifies that logged response and time allocation ratios vary linearly with logged reinforcer ratios.

Methods

Congenic D₂R knockout (KO) and wild-type (WT) mice were exposed to concurrent variable-interval schedules of reinforcement with scheduled relative-reinforcement rates from 4:1 to 1:4. Effects of the D₂R antagonist (?)-eticlopride (0.1–1.0 mg/kg) were assessed in Swiss-Webster mice.

Results

Response and time allocation ratios were related to obtained reinforcement ratios as predicted by the GML. GML fits accounted for ≥92 % of the variance in allocation ratios and did not differ in D₂R KO and WT mice. Similarly, there were no significant effects of (?)-eticlopride dose on GML fits, despite effects on overall response rates.

Conclusions

The current results demonstrate that neither deletion nor acute blockade of D₂Rs affects choice among response alternatives varying in food-reinforcement frequencies. Because previously published results suggest a role of D₂Rs in choice between response alternatives differing in reinforcer magnitude and delay or magnitude and probability, the current findings suggest that D₂Rs play a role in choice only among certain parameters of reinforcement. Furthermore, these findings suggest parameters of reinforcement may only be fungible in a complex manner.     

Incidence of Sjögren's syndrome in Japanese patients with hepatitis C virus infection

Background and Aim: Hepatitis viruses induce not only chronic liver diseases but also the impairment of other organs and tissues as extrahepatic manifestations. In particular, hepatitis C virus (HCV) is involved in various extrahepatic manifestations. The purpose of the present study was to evaluate Sjögren's syndrome (SS) and lichen planus (LP) involvement, which are various extrahepatic manifestations in patients with liver diseases related to hepatitis B virus (HBV) or HCV. Methods: We examined a total of 110 Japanese patients with chronic liver disease: 29 with HBV infections and 81 HCV infections. Results: The prevalence of SS according to European and Japanese criteria in patients with chronic HCV infection was significantly higher than in patients with chronic HBV infection (European criteria: 25.9 vs 3.4%; P < 0.05, Japanese criteria: 21.0 vs 3.4%; P = 0.05). Lichen planus was observed in one (3.4%) of 29 patients with chronic HBV infection, and in 11 (13.6%) of 81 patients with chronic HCV infection. Simultaneously combined LP and SS occurred in 8.6% (seven of 81) of patients with HCV infection, but in none with HBV infection. Conclusions: Clinicians should routinely follow the HCV‐infected patients, paying sufficient attention to the presence of SS and LP, and they should also carefully monitor their prognosis.     

Multiple Cerebral Infarctions Accompanied by Subcortical and Subarachnoid Hemorrhaging in Bilateral Border Zone Areas in a Patient with Eosinophilic Granulomatosis with Polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is often associated with peripheral neuropathy, but reports of central nervous system involvement are quite rare. We herein report a patient with EGPA first identified as having hypereosinophilia who later developed asthma, eosinophilic otitis media, sinusitis, and hemorrhagic colitis. She subsequently developed hemiparesis. Head magnetic resonance imaging revealed multiple cerebral infarctions with subcortical and subarachnoid hemorrhaging colocalized at the bilateral border zone areas. She was diagnosed with EGPA-induced stroke and successfully treated with oral prednisolone. Inflammation in the small cerebral arteries in EGPA may induce bilateral border zone infarction with colocalizing subcortical and subarachnoid hemorrhaging.     

Controlled delivery of bFGF to recipient bed enhances the vascularization and viability of an ischemic skin flap

Therapeutic angiogenesis is a promising approach to treat ischemic skin flaps. We delivered basic fibroblast growth factor (bFGF) to the recipient bed of a rat dorsal skin flap by a drug delivery system with acidic gelatin hydrogel microspheres (AGHMs), and assessed augmentation of neovascularization and flap viability. An axial skin flap was elevated on the back of male Sprague–Dawley rats, and bFGF solution or bFGF-impregnated AGHMs were injected into the recipient bed. The dose of bFGF in the bFGF solution was set to 15 (Sol-15 group), 50 (Sol-50 group), or 150 μg (Sol-150 group). Correspondingly, 2 mg AGHMs were impregnated with 15 (AGHM-15 group), 50 (AGHM-50 group), or 150 μg (AGHM-150 group) bFGF. Other groups of animals received phosphate-buffered saline (Sol-Cont group) or phosphate-buffered saline-impregnated AGHMs (AGHM-Cont group) as controls. Seven days later, analyses of the area of necrosis, microangiographic findings, and histological findings in the flap were carried out. The area of necrosis in the AGHM-150 group was significantly smaller than that in the other groups. Microangiographic and histological analyses showed that neovascularization of the ischemic skin flap significantly increased in the AGHM-150 group as compared with the Sol-150 group and the AGHM-Cont group. These findings suggest that continuous delivery of bFGF to the recipient bed by bFGF-impregnated AGHMs enhances the viability of an ischemic skin flap.     

Gastrin Receptor Gene Expression in Several Human Carcinomas

Gastrin has been shown to enhance the growth of various human tumors. The present study was designed to examine the gastrin receptor gene expression in various human carcinoma cell lines and in surgically resected carcinoma tissues. By Northern blot analysis, gastrin receptor mRNA was detected in 3 out of 7 small cell lung carcinoma cell lines. Gastrin receptor mRNA was also expressed in one out of 8 colon carcinoma cell lines and 2 out of 10 colon carcinoma tissues. Moreover, one of two small cell carcinoma cell lines of the stomach clearly expressed gastrin receptor mRNA. However, none of the gastric adenocarcinoma cell lines or surgically resected gastric adenocarcinomas tested had any detectable expression of gastrin receptor gene. These findings may suggest a role of gastrin receptor in the growth and differentiation of certain human carcinomas.     

Distraction and tissue regeneration

Distraction osteogenesis has become a popular method of bone regeneration since 1980's in Japan. Bone is a regenerative tissue and its distraction enhances bone regeneration and remodelling. We review the relationship between distraction osteogenesis and tissue regeneration.     

Enhanced effects of central angiotensin II on cardiovascular and drinking responses in inbred polydipsic (STR/N) mice

STR/N, an inbred strain of mice, is known to exhibit extreme polydipsia and polyuria. The objective of this study was to investigate the possible reasons for polydipsia. First, comparisons were made between STR/N mice and control mice from the Institute of Cancer Research (ICR) concerning daily drinking, urinary excretion, and basal cardiovascular function. Then, since angiotensin II (ANG II) is a potent stimulus for drinking behavior, we investigated the effects of intracerebroventricular (i.c.v.) administration of ANG II on cardiovascular and water intake responses. Daily water intake, food intake, urinary volume, and urinary electrolytes (Na and K) excretion were larger in STR/N mice than in ICR mice, and the basal blood pressure was significantly lower in STR/N mice than in ICR mice. The i.c.v. administration of ANG II (10 pmol/per mouse) resulted in increased mean arterial blood pressure (MAP) and water intake in both STR/N and ICR mice, but the changes in MAP were significantly larger in STR/N mice than in ICR mice. These results suggest that polydipsia in STR/N mice is at least partially attributable to high sensitivity of central ANG II receptors and low MAP.     

A case of medial temporal lobe epilepsy associated with occult focal cortical dysplasia in the lateral temporal neocortex]

A 29-year-old male with medial temporal lobe epilepsy(MTLE) was revealed to have "occult" focal cortical dysplasia(FCD) in the lateral temporal neocortex. He had no history of febrile convulsion and developed complex partial seizure at the age of 14 year, which became intractable. Although MRI failed to reveal structural abnormality in the temporal lobe, even retrospectively, the findings of non-invasive preoperative examination, such as video-EEG monitoring and interictal ECD-SPECT and FDG-PET, were consistent with those of the left MTLE. Intraoperative electrocorticography(ECoG) demonstrated almost continuous paroxysmal activities on the anterior part of the inferior temporal gyrus(ITG). Anterior temporal lobectomy(ATL) with hippocampectomy was performed. Histological examination revealed FCD in the small area with 0.8 mm in diameter of the resected ITG. In the ATL without preoperative invasive examination such as chronic subdural electrode recording, intraoperative ECoG recording is mandatory.     

Cell cycle regulation by the Wee1 Inhibitor PD0166285, Pyrido [2,3-d] pyimidine, in the B16 mouse melanoma cell line

Background  

Wee1 kinase plays a critical role in maintaining G2 arrest through its inhibitory phosphorylation of cdc2. In previous reports, a pyridopyrimidine molecule PD0166285 was identified to inhibit Wee1 activity at nanomolar concentrations. This G2 checkpoint abrogation by PD0166285 was demonstrated to kill cancer cells, there at a toxic highest dose of 0.5 μM in some cell lines for exposure periods of no longer than 6 hours. The deregulated cell cycle progression may have ultimately damaged the cancer cells. We herein report one of the mechanism by which PD0166285 leads to cell death in the B16 mouse melanoma cell line.