[Management of traumatic threatened retinal detachment]

10 cases of symptomatic retinal tear and discoid edema from perforating injury are reported as traumatic threatened retinal detachments. All 10 patients were fresh cases with clear refractive media, among them were 1 case of retinal discoid edema that led to retinal detachment, subsequently cured by secondary operation, 3 cases of symptomatic retinal tear that were surrounded by photocoagulation, and 6 cases of discoid edema that were encircled by photocoagulation 'dams' to absorb the subretinal fluid for final photocoagulatory closing of the perforation. All these 9 cases were saved from retinal detachment by prophylactic photocoagulation at an early stage.

Tissue and age specific expression of the myc proto-oncogene family throughout the life span of the C57BL/6J mouse strain

The expression of the proto-oncogene myc family (c, L and N) in terms of steady-state mRNA levels was determined in seven different normal non-cancerous tissues throughout the life span (seven different ages) of the C57BL/6J male mouse strain. C-myc oncogene expression was highest in prenatal and newborn ages and then decreased to its lowest levels at about 6 months of age. With further increase of age, a progressive pattern of increase in expression of c-myc was found in brain, liver, skin, and small intestine. However, for kidney, spleen and heart, little or no significant change was evident. Significant differential expression of c-myc was found in most tissues in animals of the same age, with highest expression consistently being found in spleen and liver at all ages. For the N-myc and L-myc oncogenes, expression was also highest in prenatal and newborn tissue as compared to the 6-month young adult, but little or no further change was found at older ages. However, substantial tissue-dependent differences in expression were also found, and no expression at all was detected at any age for N-myc in liver and for L-myc in heart, small intestine and liver. Taken together, these results indicate that the expression of the proto-oncogenes c-, L- and N-myc is dependent not only on tissue and embryonic development, as previously shown by other workers, but also on age past the young adult stage of life span. The age-dependent increase in expression of c-myc oncogene found in normal-appearing non-cancerous tissues is of particular interest as possibly reflecting tissue alterations related to both the aging process and the age-dependent increase in cancer incidence.

[Effect of cardiac sympathetic nerves on changes of TXB2 and 6-keto-PGF1 alpha in venous blood of ischemic myocardium]

Experiments were performed on 54 anesthetized, open-chest dogs to observe the effect of cardiac sympathetic nerves and alpha- and beta-adrenoceptor blockades on changes of platelet function during the early phase of myocardial ischemia. It was shown that contents of TXB2 and 6-keto-PGF1 alpha after coronary occlusion were markedly increased, and the platelet count was reduced in the coronary venous blood of ischemic myocardium. It was found that the changes in parameters of platelet function after coronary occlusion were significantly relieved by topical application of lignocaine-soaked gauze pads to the ischemic area of the heart or by bilateral stellectomy for blocking impulse of afferent and efferent of cardiac sympathetic nerves, compared with changes in parameters of control group, P less than 0.01. On the other hand, changes in parameters of the control group could be restored by intravenous infusion of noradrenaline to dogs which bilateral stellectomy was performed on, but not by infusion of normal saline. Different effects of alpha- and beta-adrenoceptor blockades on the changes in aforementioned parameters were found. The changing degrees in elevation of TXB2 and 6-keto-PGF1 alpha and in decrease of platelet count were significantly relieved by intravenous infusion of yohimbine (an alpha 2-blocker), phentolamine (a nonselective alpha-blocker), and propranolol (a beta-blocker), but not by infusion of prazosin (an alpha 1-blocker). Results were compared with the control group, P less than 0.01. These results suggest that cardiac sympathetic nerves play an important role for the changes of platelet function during the early phase of myocardial ischemia and that, yohimbine and phentolamine may exert an improving effect by blocking alpha 2-receptors on the platelet membrane, and propranolol may directly contribute to stabilization of the platelet membrane.

[Diagnosis of intraocular foreign body by computed tomography]

To evaluate the computed tomography in diagnosis of foreign bodies in the eye or close to the scleral wall, it was used with routine orbital radiography for comparison. The Simens Somatom DR3 CT Scanner with a 512 x 512 matrix was used in 50 random cases, and 45 cases were confirmed by surgery. The results indicated that the positive rate of CT in detecting intraocular foreign bodies was 98% (49/50), vs 90% (45/50) for radiography. The smallest metallic intraocular foreign body detected by CT was 0.4 x 0.25 mm and a cupric foreign body of 0.2 x 0.1 mm escaped detection. The error rate of CT in detecting single foreign body in the ocular wall was 1/30, while that of radiography was 10/30. Intraocular multiple foreign bodies could be demonstrated by multiple laminae of CT, and non-metallic foreign bodies could also be differentiated.

Restriction endonuclease cleavage map of mitochondrial DNA from Peking duck liver

Mitochondrial DNA of the liver from Peking duck was cleaved by restriction endonucleases EcoRI, BamHI, PstI and BglI into 1, 2, 4 and 5 fragments, respectively, while the BglII was without any cleavage. The restriction map of this mtDNA was constructed by measuring the length of restriction fragments using both electrophoresis analysis and electron microscopy. The position of D-loop and the direction of replication of the mtDNA were also determined.