Biomedical subjects
Publications and source records attributed to Z Yang.
The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopaedic surgeon. Initial history, physical findings, and roentgenographic examinations are indicated below. The final clinical and roentgenographic differential diagnoses are presented on the following pages.
The histomorphological influences of ovariectomies and estradiol injections on the nasal mucosa were observed in adult female guinea pigs. In the mucosa of ovariectomized guinea pigs, degenerative changes including dissolving and desquamation of cilia and glandular hypotrophy were found. On the contrary, thickening layer of the epithelium, spongiosis and edema of the corium, hyperplasia of glands and increased density of cilia were observed in the mucosa of guinea pigs receiving estrogen. The results demonstrated that different levels of estrogen might have different effects on the nasal mucosa.
The excellent visualization and atraumatic surgical techniques of endoscopic sinus surgery have been applied to the management of five cases of cerebrospinal rhinorrhea in the last 3 years. In all the cases, the exact sites of the lesion were identified on ethmoid roof (2 cases) or sphenoid sinus (3 cases). The procedures of the operation were as follows: to enlarge the leak and at the same time to block up it with the muscles, and then covering the muscles with fascia. All of the five cases were cured by one-step surgery. The techniques and indications for endoscopic management of cerebrospinal rhinorrhea are discussed.
Since 1957, the authors repaired 119 cases of nasal tip and alar defects using four kinds of method: (1) 27 cases by full-thickness skin graft; (2) 36 cases by free auricular composite graft; (3) 12 cases by local skin flap; (4) 44 cases by upper arm tube flap. The operation method was selected according to the size of nasal defect, available quantity of the remnant nasal tip and ala, and the soft tissue around the defect. The following problems were discussed in detail: (1) the principles of the selection of repairing method; (2) operative procedure; (3) the key points for the repair of nasal defects.
In order to investigate the effect of fluid resuscitation of burn shock according to Parkland formula and to find out whether it leaves any damage due to hypoxia, 22 male mongrel dogs with 50% III degrees burn were divided randomly into two groups. Group 1 (14 dogs) received no fluid replacement, whereas in group 2 (8 dogs) Ringer's lactate solution was given according to Parkland formula after the injury. Swan-Ganz catheter was inserted to the pulmonary artery before burn. FAP, CVP, PAP, cardiac output and blood gas analysis were measured preburn and at 2, 6, 12, 18, 24, 36 and 48 hours postburn. The results demonstrated that group 1 dogs all died within 12 hours postburn and group 2 dogs all survived over the shock period. However, even in these survived dogs, markedly decreased cardiac output and oxygen consumption were observed over the first 18 hours postburn. This indicated that fluid replacement according to Parkland formula can not completely correct the inadequacy of tissue perfusion, and it may leave certain damage of oxygen deficiency. Therefore, further improvement in fluid resuscitation and combined treatment for early burn shock to raise cardiac output and improve tissue oxygen delivery may be needed.
The plasma SOD and MDA content were determined in 50% III degree burn dogs with delayed fluid replacement. The results showed that the activity of plasma total SOD and CuZn-SOD rapidly declined and were obviously lower during the first 5 days postburn than preburn values, while the content of Mn-SOD did not show significant change. The plasma MDA was evidently elevated in 24 hour but returned to the normal level in 48-72 hours after burn, however it distinctly rose again after 72 hours post-burn. The results suggest that delayed fluid replacement induced generation of free radicals after burn injury, with the result of the occurrence of lipid peroxidation.
To investigate the effects of endotoxin (ETX) on coronary circulation, we infused endotoxin (4ng/ml) intravenously in a small dose (0.3ng/kg.min-1) which did not reduce the blood pressure, nor did it disturb the coronary autoregulation, and the flow kept constant during the ETX infusion. But when the left coronary artery descending branch (LAD) was narrowed and the LAD pressure was reduced to 4.67kPa, the ETX showed a vasodilator effect on the LAD (pre-ETX 65.2 +/- 29.2 ml/min, post-ETX 89.5 +/- 32.7 ml/min, P < 0.05). This effect suggested that the ETX in a small dose had a vasodilator effect on a narrowed coronary artery, even when it did not disturb the hemodynamics. The possible mechanisms were surveyed preliminarily.
This paper reports the studies on the positive inotropic effect of the novel domestic cardiotonic agent, vesnarinone on isolated papillary muscle and atrium of guinea pigs and rabbits, and on the comparison of the positive inotropic effect and toxicity of vesnarinone with amrinone, milrinone and strophanthin. The result suggests that vesnarinone has an apparent dose-effect relationship on a positive inotropic effect, the strength of which is between amrinone and milrinone. The positive inotropic effect of vesnarinone is higher and the toxicity is lower than that of strophanthin.
The relationship between the mortality of cerebro-vascular diseases and farmer smokers in Shifang County was studied. The results indicated that the mortality of cerebro-vascular diseases in the male groups of cigarette-smokers older than 65 and cigar-smokers older than 55 was significantly higher than that of the nonsmokers (P < 0.05), the RR being 1.68-3.22. Also, the mortality in the female groups of cigarette-smokers older than 55 and cigar-smokers older than 65 was significantly higher than that of the non-smokers (P < 0.05), the RR being 1.99-3.19. The sex-specific mortalities of the other age groups revealed no significant differences in spite of some inequalities in smoking (P < 0.05). Age should be one of the risk factors for the death of cerebro-vascular diseases regardless of the sex. The mortality rose with the increasing accumulated amount of smoking. The relationship was not significant between the mortality of cerebro-vascular diseases and short-term smokers with small dose (P > 0.05). However, when the accumulated amount reached certain degree, i.e. the smoker consumed cigar more than 270 kg or consumed cigarette more than 10,000 packs, the relationship between the behavior of cigar-smoking and cigarette-smoking and the mortality became apparent, the RR being 2.53-3.91 (P < 0.01).
Several estimates of the evolutionary distance between two homologous protein sequences were deduced, taking into account of the variation of replacement rate over amino acid sites. A maximum likelihood estimator was also presented with consideration of different probabilities of replacement among amino acids. Suggestions were made as to the application of these distance estimates to real sequence analysis.
The authors used the superficial temporal artery island flap in 34 cases for the reconstruction of the defective eyebrows and obtained good results. The present article introduces the operation technic and the following problems were discussed in detail: how to keep the grafted island flap survive; how to maintain the configuration of the reconstructed eyebrows; the principles of the operation designs.
Plasma renin activity (PRA), angiotensin II (AII), atrial natriuretic peptide (ANP) and AII/ANP were determined by radioimmunoassay in samples of blood from 59 burn patients. The results demonstrated that PRA, AII, ANP, AII/ANP increased significantly postburn. The increased level of AII/ANP correlated positively with the extent of burn injury as well as the severity of postburn renal dysfunction suggesting that the imbalance of AII and ANP played an important role in the pathogenesis of postburn renal damage.
Markov process models of nucleotide substitution are evaluated. A model proposed by Lanave et al (1984), alleged to need no priori assumption about the substitution pattern, is found to have the assumption of reversibility. Calculations based on the 2-p, 4-p, and 6-p substitution schemes show that site variation of substitution speed leads to serious under-estimation of sequence divergence by various methods. Spatial pattern variation also leads to under-estimation, but the discrepancy is slight. A nonhomogeneous Markov process model is used to study the temporal variations of rates and it is shown that the estimated number of substitutions reflects a rate averaged over time. The implications of those results to evolutionary phylogenetics are discussed.
Seven cases of empty sella syndrome were reported, among them 2 cases were primary empty sella syndrome, 5 cases were secondary empty sella syndrome. 5 cases were operated with the obliteration by transsphenoidal approach, 2 cases were operated by transfrontal approach. 6 cases were cured, the symptoms in one case was not improved due to the primary hydrocephalus. This syndrome is associated with defect of sellar diaphragm, benign intracranial hypertension, long-term administration of Bromocriptine, surgery and radiotherapy of pituitary gland. Main clinical features are headache, damage of vision and visual fields, hypopituitarism. Obliteration of empty sella by transsphenoidal approach is a simple and effective method.
Hyperthermia is a promising adjuvant cancer treatment modality. However, unresolved engineering problems with the production and regulation of temperature distributions within tissues in vivo have frustrated repeated efforts to implement clinical hyperthermia protocols. A major technical problem with hyperthermia production in vivo is the cooling effect caused by circulating blood in larger vessels. Larger blood vessels, when located in heated tumors, can prevent achievement of sufficiently high temperatures, resulting in loss of therapeutic effect. One possible way of circumventing this problem is the delivery of a critical heat dose during a short-term, high-temperature treatment episode to minimize cooling from blood flow. We investigated the concept of such rapid, high-temperature heating of tissue in a two-dimensional finite element numerical model. The model demonstrates the feasibility of interstitial radiofrequency delivery of a therapeutic heat dose, equivalent to 30 min at 43 degrees C, to a 1 cm3 tumor during a 60-s period. The model assumes circulation of cooling fluid through hollow electrodes. A post processor has been designed to display a 3-D image of the temperature distribution, electric field, and thermal dose delivered to a unit volume within the heated tissue.
The clinicopathologic features of carcinomas of the esophagus and the cardia in young patients were reviewed in a study of 1302 consecutively treated patients. The patients were divided into two groups, with group I aged under 40 years and group II over 40 years. There were no significant differences between the two groups with regard to sex ratio, duration of the principal symptoms, and 5-year and 10-year survivals. The main clinicopathologic difference between the young patients and the older ones was that the carcinomas in young patients were more likely to invade the surrounding tissues. Local lymph node metastases and microscopic residual tumor at the line of resection were also more prevalent in the young patients, but not to a statistically significant degree. These findings suggested that the clinical and pathologic features of carcinomas of the esophagus and the cardia in young patients were not significantly different from those in older patients.
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