Substantia nigra damage induced by ischemia in hyperglycemic rats

Summary Preischemic hyperglycemia induced by feeding or glucose infusion worsens the brain damage and the clinical outcome following ischemia of a given duration and density, and characteristically causes postischemic seizure activity. Light microscopy has previously showed that, in the rat, transient hyperglycemic ischemia induced by bilateral carotid occlusion in combination with arterial hypotension causes a uni- or bilateral lesion in the pars reticulata of the substantia nigra. Since this region has a central role in preventing seizure discharges the present study was carried out to determine the ultrastructural characteristics of this lesion. In rats with 10 min of transient hyperglycemic ischemia followed by recirculation for 1 to 18 h, the pars reticulata of the substantia nigra showed signs of status spongiosus, as well as extensive nerve cell alterations. These changes were observed after all recovery periods studied. The spongiotic appearance was mainly caused by swelling of dendrites and, to a lesser degree, by astrocytic swelling. The dendrites were expanded at all recovery times but the severity increased during the later periods of recirculation. These swollen dendrites contained severely expanded mitochondrias and endoplasmic reticulum. The cytoskeletal elements showed disordered lining of microtubules. Two major types of nerve cell alterations were present: a pale and a dark variety. The pale type was the most frequent cell alteration. It occurred in all experimental groups and at all time points. Redistribution of the nuclear chromatin and of cytoplasmic organelles as well as swelling of the same type as in the dendrites were the essential changes. The dark neurons were much fewer in number and occupied a peripheral position in the pars reticulata. Astrocytic foot processes appeared to be dilated around the dark neurons. Swelling of astrocyte processes was most pronounced in the 1 h recovery animals. Both types of neurons showed severe mitochondrial alterations of the type observed in dendrites. Occasionally, mitochondrial alterations were found in astrocytic processes as well. Blood vessel alterations were lacking. Previous studies have shown that in this model of ischemia the substantia nigra has a relatively well-preserved blood perfusion. In view of this the extensive histopathological lesions are surprising. We speculate that the lesions primarily involve excitotoxic damage to dendrites, with pronounced lactic acidosis playing a contributory role in causing axonal and glial pathology as well.Supported by grants from the Swedish Medical Research Council (project 12X-03020 and project 14X-263) and from the U.S. Public Health Service via the N.I.H. (grant No. 5 RO1 NS07838)     

Effect of intracarotid bradykinin infusion on cerebral blood flow in dogs

We examined whether intracarotid infusion of bradykinin altered circulation in the normal canine brain. Twenty-four anesthetized dogs were divided into four groups receiving different doses of bradykinin (1, 2.5, 5, and 10 micrograms kg-1 min-1). Regional cerebral blood flow (rCBF) was measured continuously using laser Doppler flowmetry through a burr hole in the frontal bone. Systemic blood pressure (SBP) and heart rate (HR) were monitored simultaneously. Higher doses of bradykinin significantly but temporarily decreased rCBF and SBP immediately after the start of infusion; these parameters rapidly recovered and then were stable through the rest of the infusion. During this period, percent change in rCBF and SBP was small, and differences between groups were not significant. On the other hand, HR increased during infusion and remained high. SBP, rCBF, and HR returned to pre-infusion levels after bradykinin was stopped. The results suggest that intracarotid infusion of bradykinin for treatment of brain tumors would be safe in terms of circulation to the uninvolved brain.     

Carbamazepine induced hyponatremia

Carbamazepine (CBZ) is a drug which can induce the syndrome of inappropriate antidiuretic hormone (SIADH). Until 1980's, there were reports regarding CBZ-induced SIADH, but it is rarely reported these days. We here report two cases of CBZ-induced SIADH. Hyponatremia in these cases was rapidly improved by withdrawal of administration of CBZ. According to the previous reports, the rate of hyponatremia in patients receiving CBZ is not small. It ranges from 48% to 31%. As CBZ is frequently used for patients with epilepsy and neuralgia, not only their blood CBZ concentration but also their serum Na level should be monitored.     

Clinical outcomes of coronavirus disease 2019 and seasonal influenza in patients with hematological disorders: a retrospective study

Objective: The differences in clinical outcomes in hospitalized patients with hematological disorders (HD) who developed either coronavirus disease 2019 (COVID-19) or seasonal influenza (SI) are not fully understood. To examine these differences, we retrospectively analyzed the baseline characteristics and clinical outcomes of hospitalized patients with HD admitted from 2016 to 2021.Patients and Methods: Patients with HD who developed COVID-19 (in the past 1 year) (n=21) or SI (in the past 5 years) (n=23) in the Department of Hematology/Oncology, Asahikawa Kosei General Hospital were evaluated.Results: The median ages of the patients with HD with either COVID-19 or SI were 80 and 68 years, respectively (P=0.03). The groups showed no significant differences in sex ratio, body mass index, or Eastern Cooperative Oncology Group performance status. In the COVID-19 and SI groups, the most common primary diseases were diffuse large B-cell lymphoma (43%) and multiple myeloma (39%), respectively. The median numbers of days of oxygen administration (8 vs. 0 days), quarantine (25 vs. 6 days), and hospitalization (72 vs. 21 days) were significantly higher in HD patients with COVID-19 than those in HD patients with SI (all P<0.001). The overall 90-day survival of patients with HD and COVID-19 was significantly shorter than that of patients with HD and SI (P=0.019). Moreover, patients with HD and COVID-19 had a higher risk of in-hospital mortality (43% vs. 9%; odds ratio, 7.50; 95% confidence interval, 1.26–82.4; P=0.01) compared to patients with HD and SI.Conclusion: Patients with HD and COVID-19 required longer periods of in-hospital medical and showed poorer survival than those with SI. During the COVID-19 pandemic, hematologists should closely monitor the condition of patients with COVID-19 to closely monitor their condition to prevent deaths.     

Hydrodynamic evaluation of axillary artery perfusion for normal and diseased aorta

Axillary artery perfusion is an attractive alternative to reduce the frequency of atheroembolism in extensive atherosclerotic aorta and aortic aneurysms. This study was conducted to evaluate the flow dynamics of axillary artery perfusion. Transparent glass models of a normal aortic arch and an aortic arch aneurysm were used to evaluate hydrodynamic properties. Streamline analysis and distribution of the shear stress was evaluated using a particle image velocity method. In the normal aortic arch model, rapid flow of 80 cm/s from the right axillary artery ran out from the brachiocephalic artery and grazed the lesser curvature of the aortic arch. There was secondary reversed flow in the ascending aorta. Flow from left axillary perfusion went straight to the descending aorta. In the aortic arch aneurysm model, flow from both axillary arteries hit the lesser curvature of the aortic arch and went into the ascending aorta with vortical flow. Distribution of shear stress was high along the jet from the ostium of the brachiocephalic artery and left subclavian artery. Flow in the aortic arch and the ascending aorta was unexpectedly rapid. Special care must be taken when the patient has frail atheroma around arch vessels or the lesser curvature of the aortic arch during axillary artery perfusion.     

Educational level of patients with germ cell tumor radiated in childhood

In order to estimate the influence of radiotherapy on the intellectual development of children with brain tumor, we investigated the educational level of 21 patients with germ cell tumor who had undergone radiotherapy. They were divided into three groups in accordance with their age at the time of radiation; under school age group (under 6 years of age), elementary school age group (from 7 to 12 years of age), and junior high and high school age group (from 13 to 18 years of age). There were 2 cases in the under school age group, one of them graduated from high school and the other is presently a junior high school student. There were 5 cases in the elementary school age group. 3 of these graduated from university, 1 is presently a university student and 1 is a high school student. There were 14 cases in the junior high and high school age group. 2 of these are university students, 7 graduated from high school, 1 is presently a junior high school student, and 4 died because of tumor progression. The mean period of hospitalization of the patients who have been admitted to university was 63.0 days, and that of patients who have not been admitted university was 135 days. There is a statistical difference (p < 0.05). It could be concluded that the period of hospitalization rather than radiotherapy seemed to influence the educational status of children with brain tumor.