Vascular morphology of the golden hamster spermatic cord

The morphology of the convoluted testicular artery and the pampiniform plexus of the golden hamster was studied by light microscopy and corrosion cast techniques combined with scanning electron microscopy. The artery was found to be totally enclosed by the pampiniform plexus, except for minor superficial areas where the artery was exposed. Although no direct connection between the artery and the vein was found in the area of apposition, the arterial and venous walls reduced their thickness by sharing a single tunica adventitia, which seemed well suited to the transfer of substances by diffusion. Many band-like structures of the venous walls were found in the deep part of the spermatic cord, suggesting that these may act as barriers to slow down the venous blood velocity. The venous wall here and there showed a stick-like endothelial bridge, suggesting that it may prevent the veins from over distension. In addition to the close relation between the artery and the vein, lymphatic vessels and mast cells were distributed widely within the connective tissue of the arterio-venous walls and venous walls. Mast cells were situated mainly in the area of apposition, especially at the base of the protruding venous wall. These morphological findings suggest that mast cells may be involved in the counter-current transfer mechanism in the spermatic cord of the golden hamster.     

18F-FDG accumulation with PET for differentiation between benign and malignant lesions in the thorax.

Recent reports have indicated the value and limitations of (18)F-FDG PET and (201)Tl SPECT for determination of malignancy. We prospectively assessed and compared the usefulness of these scintigraphic examinations as well as (18)F-FDG PET delayed imaging for the evaluation of thoracic abnormalities. METHODS: Eighty patients with thoracic nodular lesions seen on chest CT images were examined using early and delayed (18)F-FDG PET and (201)Tl-SPECT imaging within 1 wk of each study. The results of (18)F-FDG PET and (201)Tl SPECT were evaluated and compared with the histopathologic diagnosis. RESULTS: Fifty of the lesions were histologically confirmed to be malignant, whereas 30 were benign. On (18)F-FDG PET, all malignant lesions showed higher standardized uptake value (SUV) levels at 3 than at 1 h, and benign lesions revealed the opposite results. Correlations were seen between (18)F-FDG PET imaging and the degree of cell differentiation in malignant tumors. No significant difference in accuracy was found between (18)F-FDG PET single-time-point imaging and (201)Tl SPECT for the differentiation of malignant and benign thoracic lesions. However, the retention index (RI) of (18)F-FDG PET (RI-SUV) significantly improved the accuracy of thoracic lesion diagnosis. Furthermore, (18)F-FDG PET delayed imaging measuring RI-SUV metastasis was useful for diagnosing nodal involvement and it improved the specificity of mediastinal staging. CONCLUSION: No significant difference was found between (18)F-FDG PET single-time-point imaging and (201)Tl SPECT for the differentiation of malignant and benign thoracic lesions. The RI calculated by (18)F-FDG PET delayed imaging provided more accurate diagnoses of lung cancer.     

Reye-like syndrome associated with valproic acid

A case of a Reye-like syndrome during the course of treatment with VPA was reported. Hyperammonemia and severe liver damage as well as diffuse small droplets in the liver biopsy material were demonstrated. On analysis by gas chromatography/mass spectrometry of the urine immediately after the onset, the metabolites of VPA were detected together with lactate and other substances, and electron microscopic observation of liver biopsy material revealed deformation of mitochondria, disappearance of cristae and electron dense deposits in the matrix.     

Physical dependence potential of an enkephalin analog, EK-399, in rats

The physical dependence potential of Tyr-D-Met(O)-Gly-EtPhe-NHNHCOCH3.AcOH (EK-399), a novel enkephalin analog with a potent analgesic effect, was assessed in rats. The animals were given EK-399 (0.008, 0.032, 0.125, or 0.5 mg/kg), morphine (0.125, 0.5, or 2 mg/kg), pethidine (2 or 8 mg/kg), or pentazocine (2 or 8 mg/kg) every hour through an implanted intravenous cannula. After 3 days of treatment, precipitated withdrawal tests were conducted: naloxone (5 mg/kg) was administered subcutaneously. Rats treated with morphine showed withdrawal signs such as hyperirritability, salivation, diarrhea, and weight loss. Rats treated with pethidine, pentazocine, or EK-399 showed similar signs, but they were less evident than those in morphine-treated rats. In abrupt withdrawal tests after 7 days of treatment, rats treated with morphine, pethidine, or pentazocine showed weight loss, whereas rats treated with EK-399 showed little or no weight loss. In substitution tests, EK-399 suppressed the withdrawal signs in morphine-dependent rats, and vice versa. These results show that EK-399 has a morphine-like physical dependence potential that is weaker than that of morphine, pethidine, or pentazocine in rats.     

Percutaneous absorption of propranolol from gel ointment in rabbits

The percutaneous absorption in rabbits of propranolol from an alcohol-based gel ointment was studied to find a possible formulation of a transdermal dosage form which achieves a systemic effect. Gel ointments containing 1% propranolol were prepared by mixing ethanol/propylene glycol (EtOH/PG, 2:1 v/v) with 0.6 g Carbopol 934 in different amounts of water. The sum of the volumes of water and EtOH/PG was kept constant. The amount of propranolol released from the gel ointment as a function of the EtOH/PG content showed a convex relationship, giving a maximum release around 45–55% EtOH/PG. The solubility data for propranolol in various (EtOH/PG)/water mixtures indicated that a content of about 55% EtOH/PG was required to dissolve 1% propranolol in the gel ointment. In the study of percutaneous absorption of propranolol in rabbits, a gel ointment of 55% EtOH/PG, which was prepared according to the solubility data mentioned above, gave a distinctly high plasma level as compared with an ointment containing 40% EtOH/PG and conventional ointments. The mean plasma level obtained using 55% EtOH/PG, about 60 μng/ml, was comparable to the levels used for therapeutic purposes in human.     

Oxidative metabolism in the myocardium in normal subjects during dobutamine infusion

To assess the biventricular response of the clearance rate of carbon-11 acetate as an index of myocardial oxidative metabolism to increase in work-load, dynamic positron emission tomography was performed at rest and during dobutamine infusion in 14 normal subjects. The clearance rate constant (K_mono) of the left ventricular (LV) myocardium increased during dobutamine infusion (0.112±0.020 min^–1 vs 0.065±0.015 min^–1 at rest) (P<0.001) in proportion to the increase in the pressure-rate product. K_mono in the right ventricular (RV) myocardium also increased (0.080±0.018 min^–1 vs 0.034±0.013 min^–1 at rest) (P<0.001), with an excellent correlation with the LV K_mono (r=0.920). The fact that the increase in RV Kmono during dobutamine infusion was greater (158%±81%) than that in LV Kmono (79%±39%) (P < 0.005) indicates a greater increase in oxidative metabolism in the RV in response to inotropic stimulation in normal subjects. Correspondence to: N. Tamaki     

Afterload-Dependent Flow Fluctuation of Centrifugal Pump: Should it be Actively Fixed?

Abstract To evaluate the clinical meaning and effects of afterload-dependent flow fluctuation in a centrifugal pump, concomitant measurement of flow rate and mixed venous oxygen saturation (     ) was performed in 5 cases of open heart surgery in which the patients underwent cardiopulmonary bypass (CPB) with the Terumo Capiox centrifugal pump. Continuous measurement of     using the 3M CDI System 100 was performed with a disposable cuvette incorporated into the drainage circuit. After the target flow rate of 2.4 L/min/m² was obtained under a nonbeating condition, the pump rotational speed was fixed. During the cooling and low temperature period,     decreased as the flow rate spontaneously decreased but still stayed around 80% even with a 15–20% decrease in blood flow rate. This indicates that a luxury perfusion condition is ensured as long as the body temperature is kept low. In contrast, during the rewarming period,     decreased to around 70–75% despite a 15–25% spontaneous increase in flow rate. Although this level of     still indicates adequate systemic perfusion, there is a possibility of regional hypoperfusion in patients with such conditions as cerebrovascular disease. In conclusion, although diligent adjustment of the physiological fluctuating flow rate in the centrifugal pump seems unnecessary during conventional open heart surgery, manual control may be necessary especially during the rewarming period, normothermic surgery, or circulatory assist for shocked patients. From this study, we also conclude that the major benefit of the afterload-independent autoflow control system of the centrifugal pump is the improvement of safety in terms of the fixed reservoir level and the handling of cardiopulmonary bypass.     

The differences in purine metabolism between T and B lymphocytes

In this study enzyme activities involved in purine metabolism were measured in T and B lymphocytes separated by E and EAC rosetting methods. Adenosine deaminase, purine nucleoside phosphorylase and HGPRTase activities were significantly elevated in T cells, compared to the activities in B cells. There were no significant differences in adenosine kinase and APRTase activities between T and B lymphocytes. In contrast, PRPPsynthetase activities were higher in B cells than in T cells. The uptake of various radiolabeled precursors by mitogen stimulated lymphocytes was studied. The uptake of 14C-formate by the mitogen stimulated lymphocytes was markedly lower, compared to that of 14C-adenosine and or 14C-purine bases. The uptake of 14C-adenosine by PHA stimulated lymphocytes was considerably higher than that of Con A or PWM stimulated lymphocytes. However, the uptake of 14C-hypoxanthine into lymphocytes stimulated with PWM was increased by comparison with unstimulated lymphocytes. From these results it seems that adenosine plays a central role in the metabolism of T cells, and that purine bases are preferentially utilized in B cells.