A case of heparin-induced thrombocytopenia that worsened preexisting cerebral infarction]

A 75-year-old man was admitted to our hospital with dysesthesia of the right lip, dysphagia and gait disturbance. He presented with right Wallenberg syndrome and brain MR image showed a fresh infarction in the right lateral medulla. Therapy with heparin and ozagrel sodium was started. For a time his symptom improved a little, but after 8 days he developed re-infarction, thrombocytopenia and DIC, while being treated with heparin for cerebral infarction. Heparin was discontinued, and these symptoms improved quickly. The clinical course and the positive anti-platelet factor 4-heparin complex antibody suggested that these symptoms were caused by heparin-induced thrombocytopenia (HIT). HIT should be included as a differential diagnosis for progression of ischemic stroke under heparin therapy.     

Painless aortic dissection late after aortic valve replacement, presenting as superior vena cava syndrome

A 68-year-old man, who had underwent aortic valve replacement (AVR) with Björk-Shiley disc valve for aortic regurgitation 17 years ago, was transferred to our hospital complaining of facial ruddiness and swelling, without chest or back pain. Preoperative examination revealed DeBakey type II aortic dissection, which caused superior vena cava syndrome (SVC syndrome). Emergent ascending aortic replacement was performed, postoperatively central venous pressure (CVP) decreased from 33 to 9 mmHg, and SVC syndrome was relieved. Painless aortic dissection after AVR, presenting as SVC syndrome, is a rare case, and close follow-up should be performed under consideration of painless aortic dissection late after AVR.     

Abdominal vagotomy attenuates interleukin-1β-induced nitric oxide release in the paraventricular nucleus region in conscious rats

Nitric oxide (NO) has recently been shown to modulate the hypothalamic–pituitary–adrenal axis response to interleukin-1β (IL-1β). We measured levels of nitrite (NO₂⁻) and nitrate (NO₃⁻) in the hypothalamic paraventricular nucleus (PVN) region using an in vivo brain microdialysis technique in conscious rats. Intraperitoneally administered IL-1β produced a significant increase in both NO₂⁻ and NO₃⁻ levels in the PVN region. We also examined the possible involvement of the abdominal vagal afferent nerves in this effect. In abdominal-vagotomized rats, the increase was significantly attenuated compared to that in sham-operated rats. Our results suggest that the abdominal vagal afferent nerves are involved in intraperitoneally administered IL-1β-induced NO release in the PVN region.     

The Basomedial and Basolateral Amygdaloid Nuclei Contribute to the Induction of Long-term Potentiation in the Dentate Gyrus In Vivo

Recent behavioural studies have provided evidence that the amygdala modulates hippocampal-dependent memory. To test the possibility that the amygdala modulates hippocampal synaptic plasticity, we investigated the effects of surgical lesions of the amygdaloid nuclei on the induction of long-term potentiation (LTP) in the dentate gyrus of anaesthetized rats. Previously we reported that LTP in the dentate gyrus was attenuated by lesion of the basolateral amygdala, but was not affected by lesion of the central amygdala. In the present study, dentate gyrus LTP was significantly attenuated by basomedial amygdala lesion but not by medial amygdala lesion. These results suggest that, among the amygdaloid nuclei, the basomedial and basolateral nuclei are involved in the modulation of hippocampal plasticity. The roles of the basomedial and basolateral amygdala were further supported by experiments examining the effects of electrical stimulation of these nuclei. High-frequency stimulation of the basomedial amygdala alone did not induce dentate gyrus LTP, but when applied at the same time as tetanic stimulation of the perforant path increased the magnitude of the dentate gyrus LTP. Similarly, high-frequency stimulation of the basolateral amygdala enhanced LTP induced by tetanic stimulation of the perforant path. Furthermore, facilitation of dentate gyrus LTP by basomedial or basolateral amygdala stimulation was observed even in rats lesioned in either amygdala, suggesting that neurons in the basomedial and basolateral amygdala can modulate dentate gyrus LTP independently. Activity-dependent facilitation of hippocampal plasticity by the basomedial and basolateral amygdala may underlie memory processing associated with emotion.     

Treatment strategies for hepatic metastasis from colorectal cancer

Hepatic micrometastases of the parenchyma adjacent to a macroscopic lesion were detected in 17 of 31 resected liver metastases. Fifty-nine micrometastatic lesions were detected in total; 26 lesions were situated in the portal vein (PV), 22 in the central vein (CV), 5 in the bile duct (BD), and 6 in the sinusoid (SS). A histological study confirmed the direct invasion of the macrometastatic cancer cells into the adjacent PV, CV, BD, and SS. According to the tumor doubling time, the mean diameter of the macrometastases in 19 remnant livers was calculated to have been 0.57±0.87 cm at the time of the primary resection. The calculated diameter of 3 of these 19 macrometastases was found to be less than 0.01 cm, the minimum implantable size, indicating that the cancer recurrence in these specimens may have developed from macroscopic metastatic lesions as a satellite, and not from the primary tumor. In 13 patients who received doses of 5250 mg or more of 5 fluorouracil (FU) via the hepatic artery, the cumulative disease-free rate 2 years postoperatively was 100%; this value was 47.6% in 11 patients who received less than 5250 mg of 5 FU via the hepatic artery, and 0% in 39 patients who received no chemotherapy (P<0.005). These results suggest that anatomical hepatic resection for satellite lesions, combined with prophylactic hepatic arterial chemotherapy for micrometastases, decreases the recurrence rate of hepatic metastases in the remnant liver.