Differentiation between cerebral embolism and thrombosis on sequential CT scans

A differentiation between embolic versus thrombotic infarction has been attempted on the basis of sequential CT of 32 patients fulfilling our clinical and angiographic criteria for embolic or thrombotic cerebral infarction of the middle cerebral arterial distribution. In the 20 patients of the embolic group, a large homogeneous low attenuation area was seen in every case. In 18 of these 20 patients, the low attenuation area extended from the deep brain to the cortex. In the 12 patients of the thrombotic group, 10 had an inhomogeneous low attenuation area that did not involve the cortices in 8 cases. The frequency of hemorrhagic transformation in the embolic group was higher than in the thrombotic group. Computed tomography showed discrete areas of increased attenuation corresponding to an angiographically occluded artery in 7 of the 20 patients in the embolic group. Sequential CT can assist in differentiating between embolic and thrombotic infarction.     

Intensive induction chemotherapy of adult acute myelogenous leukemia by continuing daunorubicin, behenoyl-cytosine arabinoside, 6-mercaptopurine and prednisolone until marrow aplasia]

Intensive induction chemotherapy was applied to 25 patients with acute myelogenous leukemia by continuing drugs (daunorubicin, behenoyl-cytosine arabinoside, 6-mercaptopurine and prednisolone) until the achievement of severe bone marrow aplasia (leukemic cells less than 1,000/microliters). Complete remission (CR) was achieved in 18 (72%). Numbers of partial remission and an early death were 5 (20%) and 2 (8%), respectively. Although median nadirs of white blood cells (WBC) and platelet counts (Pl) (205/microliters and 8,200/microliters, respectively) were remarkably low, recovery of WBC (over 1,000/microliters) and Pl (over 50,000/microliters) were achieved in 23.8 and 24.5 days, after an initiation of the chemotherapy. Sepsis was a most frequently observed complication during induction stage and a duration of fever was 2-48 days (median 15). Median duration of CR was 22.9 months. Unexpectedly, 11 of 17 CR (except one with bone marrow transplanted) relapsed after 4.2-41.4 months (median; 9.4), but 6 (35.3%) still remain in first CR for 30.5-72.9 months (median; 51.4). A long-term survival might be obtained by intensifying induction chemotherapy in about one fourth of patients, but the intensification or application of non-cross resistant anti-leukemic agents in post-remission therapy may be required to avoid relapses even if induction is intensified.     

Long-term results of aortic root replacements with pulmonary autografts (Ross Procedure) in five cases

Aortic root replacement with a pulmonary autograft (the Ross Procedure) has been successfully performed in our hospital since November, 1992. The long-term results of five of the earliest cases are reported in this paper (2-3 year follow-up). The patients’ ages were two months to eighteen years old. Four of the patients suffered from aortic valve stenosis, and one suffered from aortic regurgitation. Severe left ventricular failure was recognized in three cases. However, the patients recovered from surgery smoothly and without significant aortic regurgitation and left ventricular outflow tract gradients. A serious concern exist as to whether the implanted autograft in 2 months old infant would grow. In this patient, postoperative cardiac catheterization was performed after sixty days, one year, and two years. The diameter of the anulus of the pulmonary autograft enlarged from 12 mm to 18 mm over the period of two years. Compared with the calculated aortic valvular diameter from a standardized body surface area, these diameters were equivalent to 150%–162% of the standardized size at each age. The implanted pulmonary autograft has subsequently enlarged gradually and proportionally. Its function as an aortic valve was maintained even after significant enlargement of the aortic anulus to 18 mm. We therefore conclude that the Ross procedure can be recommended because of the apparent ability the pulmonary autograft to grow over time.     

Positron emission tomography (PET) study in patients with meningiomas

Regional hemocirculation and metabolism were evaluated in five patients with meningiomas using positron emission tomography (PET). Histological diagnoses were: two cases of meningotheliomatous type, one hemangiopericytic type, one fibroblastic type, and one transitional type. Regional cerebral blood flow (rCBF), blood volume (rCBV), oxygen extraction fraction (rOEF), and metabolic rates of oxygen (rCMRO2) and glucose (rCMRG1) were measured with 15O2, C15O. 15O2, and 18F-fluorodeoxyglucose tracers. For the quantitative analysis, regions of interest were delineated on tumors, the peritumoral region, and the contralateral gray matter in comparison with age-corresponding 5 malignant gliomas and 5 normal volunteers. Tumor hemocirculatory parameters (rCBF: 57.2 +/- 22.6 ml/100 ml/min, rCBV: 7.95 +/- 3.27 ml/100 ml, mean + SD, n = 5) were markedly higher than those of the contralateral gray matter (p less than 0.05 by a Student-t test). The high values were consistent with angiographic findings of tumor staining and with abundant tumor vessels demonstrated by pathological examination. rCMRO2 was 2.15 +/- 0.80 ml/100 ml/min, which were comparable to those of the contralateral gray matter. Tumor rCMRG1 showed 4.76 +/- 2.37 mg/100 ml/min; the values of two cases were similar to the respective gray matter. The raised metabolic rate (rCMRO2/rCMRG1) therefore suggests rather aerobic glycolysis as compared with gliomas. Low rOEF (0.26 +/- 0.16) reveals an excessive blood flow beyond oxygen demand of the tumor. In the peritumoral regions, rCBF and metabolism fell slightly but rOEF reached a level similar to the contralateral gray matter, possibly due to hemocirculatory stasis caused by intracranial hypertension; in contrast, an unmatched reduction of rCBF and rCMRO2 implies tumor cells infiltration in gliomas.(ABSTRACT TRUNCATED AT 250 WORDS)     

Age-related changes in neuronal RNA content in rhesus monkeys (Macaca mulatta)

The prefrontal cortex and subiculum of the hippocampal formation was sampled from 10 Macaca mulatta aged 7 to 30 years. There was no significant difference in RNA content of frontal and subicular neurons between 7 and 20 years. The mean RNA content was 22.86 pg for the cortical and 45.14 pg for the subicular neuron. Contrarily, a significant decrease in neuronal RNA content in both the prefrontal cortex and the subiculum was found for the four M. mulatta of advanced age. The oldest M. mulatta aged 27 to 30 years revealed a mean RNA content of 16.8 pg for the prefrontal cortex and 33.5 pg for the subiculum. Age-related RNA changes in M. mulatta was discussed in relation to that in the human brain.     

Epidemiological model of typhoid fever and its use in the planning and evaluation of antityphoid immunization and sanitation programmes

An epidemiological model has been constructed for typhoid fever in a stable population in order to study the transmission of infection at different levels of endemicity. It involves a number of parameters representing the proportions of epidemiological subgroups in the population—such as the susceptible, the infected, and the immune—and rates of transition between the groups. Numerical values based on available evidence were assigned to the parameters, to provide a realistic simulation of stable endemicity.