Volume 101  ·   Issue 04  ·  1988

Large dose MPTP treatment given to the mouse could bring about a reduction of methionine-enkephalin (MEK) and leucine-enkephalin (LEK) in the mouse striatum. The average levels were reduced by 75% for MEK and 66% for LEK as compared with the controls. The monoamine oxidase B inhibitor L-deprenyl could prevent the MPTP-induced peptidergic neurotoxicity. Hence, MPTP-treated mouse may be a useful model to study peptides and Parkinson's disease.

Five anti-a monoclonal antibodies (McAbs) were selected and directed to separate epitopes of group a determinant on hepatitis B surface antigen (HBsAg). The method was set up to define the quantitative difference of these epitopes on HBsAg identified by McAbs with 125I-labelled rabbit anti-mouse immunoglobulin antibody (125I-R-M-Ab). The difference of epilope numbers on HBsAg was expressed as epitope density. Each of the 5 epitopes was of the same density in 3 subtypes of HBsAg (adr, 5 samples; adw, 3; and ay, 4). The average density of the 5 epitopes, identified by McAbs, MHSA 11, 1H9-G11-D7, MHSA l, 3Cl-H7 and 2B8-E8, on the 12 HBsAg samples was expressed as 39±3%, 27±2%, 17±2%, 12±2% and 6±1%, respectively. The 3 epitope densities identified by MHSA 1, MHSA 11 and 1H9-G11-D7 on yeast derived recombinant HBsAg were statistically different from those on plasm derived HBsAg and cell derived recombinant HBsAg (P<0.05). There were some changes of group a determinant between them.

Hydrogen breath test was performed among 5 groups of healthy Chinese population. The results showed that there was no statistically different prevalence of lactose malabsorption between two Han adult groups with or without consumption of milk 76.3% and 67.9%, P>0.05). However, the incidence of lactose malabsorption in Uygur Chinese was much lower than those of the above groups (43.5%, P<0.01). The incidence between two Han children groups (2.5-4 and 5-7 yrs) were very similar with each other (66.7% and 76.3%, P>0.05) and also consistent with that of Han adult group. All these findings support the hypothesis that the occurrence of lactose malabsorption due to lactase difficiency develops during a long period of time as a result of evolution but is not affected by living habit.

Lactic dehydrogenase (LDH) activity in aqueous humour and serum was measured of 24 patients with retino-blastoma, senile cataract, glaucoma, and choroid melanoma in addition to LDH isoenzyme fractions. The results were compared with those of the 20 normal children. The ratio of aqueous humour LDH to serum LDH was 4.32±2.80, and that of isoenzymes LDH4 to LDHl was greater than 1. The results of our study suggested that the total LDH activity and isoenzyme fractions in the aqueous humour is of value in the diagnosis of retinoblastoma.

Ranitidine, a selective H2-blocker is assessed in acute duodenal ulcer by randomized double-blind placebo controlled trial. 55 patients entered the study (27 ranitidine, 28 placebo). All had endoscopically proven duodenal ulcers and underwent further endoscopy after 4 and 8 weeks of treatment. The 4 week healing rate for ranitidine was 85% compared to 25% for placebo (p<0.01), and the 8 week healing rates were ranitidine 90% and placebo 23% (p<0.01). Pain relief was obtained after 1 week in 40.7% of the ranitidine group versus 7.2% of the placebo group. At 4th week, 66.7% of the ranitidine group were pain free versus 25% of the placebo group. No significant adverse events were encountered. Therefore, ranitidine is significantly superior to placebo in acute duodenal ulcer among Chinese patients both in terms of healing and relieving pain.

Resection of the posterior structure of the lumbar spine is one of the common operations. Conflicting views exist on the effect of this surgical procedure on lumbar spine stability. Nine functional spinal units (FSU) were divided into Groups A (normal FSU), B (total laminectomy and partial facetectomy) and C (total laminectomy and total facetectomy) and tested with the FSUs in the supine and standing positions while being subjected to loads. Displacement and rotation of sagittal planes and compression strengths were measured. The experiment showed that there were highly significant differences (p<0.01) or significant differences (p<0.05) between the 3 groups. It is suggested that the posterior structures be damaged minimally while bringing about thorough decompression and that lumbar spine stability be preserved or reconstructed.

The mechanism and clinical significance of abnormal metabolism of zinc and copper in liver cirrhosis patients are a problem to clinical workers. We performed experiments on 30 healthy dogs and studied 35 liver cirrhosis patients with portal hypertension who underwent either limited side-to-side portacaval shunt or nonshunt procedures, in order to investigate the effect of changes in portal hemo-dynamics on zinc and copper metabolism, and methods for their correction. The results showed that liver cirrhosis patients present with zinc deficiency and copper accumulation, and the concentration of zinc closely correlates with the liver function. Serum and liver zinc concentration are decreased after portacaval shunt, the rate and duration of decrease are associated with the stomal size. Oral zinc can increase the zinc level, decrease copper accumulation, improve liver function and protect hepatocytes from ischemic injury after portacaval shunt.

Human tumor tissue was incubated in the presence of bromodeoxyuridine (BrdUrd). The S-phase(DNA synthesizing) cells which incorporated with BrdUrd were detected by monoclonal antibody against BrdUrd and immunohistochemistry. The DNA synthesizing cells were also determined from a portion of the same tissue by classical tritiated thymidine (3HdThd) labeling and autoradiography. The results of BrdUrd labeling index (BrdUrd-LI) and tritiated thymidine labeling index (3HdThd-LI) obtained from the same tissue were compared. The mean BrdUrd-LI and 3HdThd-LI were quite comparable, 10.8±1.4% and 10.2±1.1%. This technic offers a fast and relatively simple alternative method for determining human tumor LI.

Visual evoked potential (VEP) topography is an equipotential mapping calculated from multichannel VEP with the help of a two dimension interpolating function. The mapping is easy to read and reliable. The authors recorded checkerboard reversal VEP topography of 30 patients suffering from tumor in region of sella turcica, of them 23 cases showed crossed asymmetry on monocular full field VEP mapping or absence of VEP, and only 2 patients had significant increase of P100 latency. Among 4 patients who had no gross visual field defects, 2 also showed abnormality on VEP topography. It indicates that VEP topography has more advantages than perimeter to diagnose early compression of visual pathway and has clinical utility in this area. When CT finding is not compatible with patient's clinical manifestation,VEP could be used to evaluate the functional change of optic pathway and thus contribute to correct diagnosis. Crossed asymmetry on full field topography could be considered as a reliable indication of chiasmal lesion.