Volume 107  ·   Issue 08  ·  1994

The patients with strabismus, including 8 with superior oblique paresis, 1 with inferior rectus paresis, and 1 with congenital constant exotropia, were examined with MR imaging at 1.5 tesla (T) or 0.5T with a surface coil. Abnormal findings of extraocular muscles were identified in 8 of the 10 patients and most of them were consistent with the clinical findings. Deviation of the optic nerves was noted in 5 patients. Coronal short repetition time (RT) and echo time (ET) images were used to measure the concerned extraocular muscles and the optic nerves. The differences in diameters between the concerned extraocular muscles of both the diseased and normal eyes were calculated. MR imaging is considered to be advantageous and can be favorably used to observe and measure the extraocular muscles and other intraorbital structures in patients with strabismus.

This review of recent literature presents new concepts to evaluate radiation hormesis in cancer mortality. Using these interpretations cancer mortality rates were found to be significantly reduced following whole body exposure to low doses of either acute or chronic irradiation. The threshold dose, the zero equivalent point (ZEP), provides a definitive limit for public health safety limits in chronic exposures. The ZEP is useful for triage following acute exposures in nuclear disasters.

A radiation-induced adaptive response has been convincingly demonstrated in a variety of cultured cells. It is associated with the activation of genes and the up-regulation of protein enzymes, resulting in a delay in cell-cycling and the opportunity to repair radiation-damaged DNA as a transient phenomenon. Just how the adaptive response operates in a multi-cellular organism is still obscure, but there is little or no evidence in rodents and the beagle dog of a shortening of lifespan after exposure to acute doses up to a few hundreds of mGy or after chronic daily exposure resulting in accumulated doses of up to a few Gy. Nevertheless there is an increase in both non-neoplastic and neoplastic diseases which need not be life-threatening. A prudent approach has been used by the ICRP in deriving a value for radiation-induced detriment at low doses from which to recommend individual dose and risk limits in their system of radiological protection. This is not to deny the possible existence of an adaptive response. However, in the opinion of the author, there is no overwhelming evidence to date which justifies the belief that exposure to low doses in the range of natural background up to a few tens of mSv reduces the incidence of radiation-induced cancer in a population composed of persons of all ages with a wide spectrum of diseases and with widely different sensitivities to radiation.

The biological effects of relative low level internal irradiation were introduced. 1. Life span studies on carcinogenesis. Pacific Northwest Laboratory observed 3782 rats given a single inhalation of 239Pu O2 at initial lung burden ranging from 0.25 to 180 nCi. Significant life span shortening was found at lung dose >8 Gy and it was indicated that the presence of a "possible" threshold of about 1 Gy for lung tumor formation. 2. Health effects of radon and its progeny. Both experimental and epidemiological survey were studied. The nominal probability coefficient (fatality) for the public and workers are 7.90 x 105 per mJhm-3 (2.77×10-4 per working level month, WLM). 3. Health effects on 3H on postnatal brain development and neurobehavior, genetic effects, carcinogenic effects and adaptive effects of 3H were investigated. 4. Study on the effects of neuroendocrine system under low level irradiation of 75Se (Auger electron emitter) and 35S (β-particles emitter). The results showed that the neuroendocrine system is very sensitive to small dose of internal irradiation.

In 18 consecutive patients receiving the transjugular intrahepatic portosystemic stent shunts (TIPSS), 15 were male and 3 female. The patients aged from 34 to 66 years had liver cirrhosis with portal hypertension and esophageal varices. Twelve had recurrent bleedings from raptured gastroesophageal varices. Shunts were established in 16 of the 18 patients and no operative death was noted. Portal vein pressure was reduced from 3.98±0.24 kPa before shunting to 2.40±0.16 kPa after shunting. Doppler ultrasound examination revealed that the maximum blood flow velocity in the main portal vein increased from 14.0±4.5 cm/sec to 48.0±16.5 cm/sec. The mean follow-up time in the successful cases was 4.5 months (range 2-8 months). The shunt patency was determined with color Doppler ultrasound in 15 patients: occlusion in one and no accites in 4. Varices disappeared in 8 patients and became less evident in 7. No patients had recurrence of varices bleeding or encephalopathy during follow-up. The results suggest that TIPSS is a safe and effective method for portal decompression in the treatment of variceal hemorrhage, and that portal vein puncture is largely dependent on understanding the three-dimensional relationships between hepatic and portal veins. To achieve an adequate portal decompression, we recommend that a stent of 12 mm in diameter be used in severe cases.

The effect of parathyroid hormone (PTH) (0.01 nM-10 nM) and 17 β-estradiol (E2, 1 nmol-10 nM) alone or in combination on 3H-thymidine incorporation, alkaline phosphatase and adenylate cyclase activities were investigated in human fetal osteoblasts using serum-free monolayer primary cultures. The results showed that PTH inhibited cell proliferation while E2 promoted it. On alkaline phosphatase activity, PTH showed a complex results while E2 were slightly inhibitory. PHT-E2 combination suggested that E2 could alter the effect of PTH alone, also potentiated the anabolic and antagonize the catabolic effects of PTH on bone formation.

C/EBP is a sequence-specific DNA-binding protein. In order to identify its distribution and localization, immunohistochemical technique (ABC method) was done using anti-C/EBP polypeptide antibodies 1103#, 425# in liver specimens from 20 normal adults, 5 neonates, 6 patients with hepatitis, 25 with liver cirrhosis, 80 with hepatocellular carcinoma (40 cases were associated with surrounding nontumorous tissues) and 26 patients with cholangiocarcinoma (15 cases were associated with surrounding nontumorous tissues). The results showed that C/EBP was diffusely distributed in nuclei and cytoplasm of differentiated liver cells and very low or undetectable in liver cancer cells. The manifestation of C/EBP correlated with degree of differentiation of tumour cells, and was obviously weaker than that in surrounding nontumorous tissues. C/EBP positive staining has also been found in regenerating epithelial cells of bile ductules. The results suggested that C/EBP should play an important role in establishing and maintaining the differentiation of liver cells.

C-erbB-2(HER-2/neu) proto-oncogene is mainly expressed in epithelial tissue and activated due to its amplification. Amplification of the C-erbB-2 proto-oncogene has been associated with poor prognosis in human ovarian cancer. Our study was to examine whether amplification is more frequently observed in ovarian cancer, or it is associated with poor prognosis of human ovarian cancer in China. The DNA of ovarian cancers was extracted and consequently digested with restriction endonuclease EcoRI, electrophoresed in 0.8% agarose gels and blotted onto nitrocellulose filter with Southern transferring method. It was then hybridized with a 32P-labelled C-erbB-2 probe and subsequently underwent autoradiography. The result has shown that the C-erbB-2(HER-2/neu) gene was amplified in 8 of 26 human ovarian cancers (30.8%). The clinical data showed that all of the 8 cases with the amplified C-erbB-2 were in their advanced stage (III-IV). Five of the patients died from 2 to 4 months after operation. These data suggest that amplification of the C-erbB-2 gene may play a role in the pathogenesis of ovarian carcinoma; it is frequently observed in advanced ovarian cancer and is associated with poor prognosis for these patients.