[Pressure control system for the hermetically sealed cabin of the recoverable satellite]

There are many precision instruments and equipment for scientific researches and experiments in the hermetically sealed cabin of satellite. Appropriate pressure must be controlled in the cabin in order to ensure the instruments and equipment from the adverse space environment. This paper describes a pressure control system for the hermetically sealed cabin in the recoverable scientific detect and experimental satellite. The cabin pressure is regulated automatically into the specific levels by venting or supplying the air from or to the cabin during launch, on orbit and before reentry of the satellite. The system has low mass, low power consumption and high reliability. It was used successfully in the recoverable satellite first in September 1987 and had been used many times since then. It is the first active pressure control system for the hermetically sealed cabin of the satellite in China.

[A micro transducer for dynamic multi-location pH monitoring in upper digestive tract]

A new transducer catheter used for dynamic multi-location pH monitoring in upper digestive tract has been developed. On the catheter several antimony electrodes and an Ag-Agcl electrode are integreted. An animal experiment compared the results of gastric aspiration and dynamic recording and demonstrated the reliability of this transducer. Clinical application has shown that this technology contributes greatly to the research on digestive physiology and to the diagnosis of functional diseases such as non-cardiac chest pain.

[Coexisting pheochromocytoma and renal artery stenosis]

OBJECTIVE

To improve the diagnosis of coexisting pheochromocytoma and renal artery stenosis.

METHOD

Four patients with coexisting pheochromocytoma and renal artery stenosis were treated.

RESULT

After removal of the pheochromocytoma, the blood pressure became normal in two patients combined with resection of kidney with renal artery stenosis, and one patient with local adhesion loosened. The hypertension, however, persisted in another patient after the resection of pheochromocytoma even though the long segment of renal artery stenosis was relieved.

CONCLUSION

After pheochromocytoma was diagnosed with its known position, coexisting renal artery stenosis should be suspected according to one of the following conditions: (1) Vascular murmurs are noted at the area of the upper abdomen or back; (2) One of the kidneys becomes less sized; (3) Using the inhibitor of receptor alpha only has no effect lowering blood pressure and it is necessary to add the inhibitor of angiotension; (4) Postoperative hypertension does not resolve when no remaining pheochromocytoma is present. the renal artery stenosis can be reversed after both removal of pheochromocytoma and loosening of adhesion in case of stenosis due to the pressure of the tumor and adhesion caused renal artery angling and local stricture. Extensive stenosis or closure, however, can not be corrected with severe atrophy of renal parenchyma due to pheochromocytoma, and the resection of kidney should be indicated.

[Bispectral analysis of EEG signal during focal cerebral ischemia]

Early noninvasive detection of cerebral ischemia is important for fighter pilots as well as in clinical diagnosis. In this paper, a model of focal cerebral ischemia was presented. Bispectrum of EEG signals recorded from ischemic region and normal region after 30 min ischemia was analyzed using the third-order recursion method, which possesses higher frequency resolving ability. It can resolve two closely spaced peaks in the bispectrum and detect the presence or absence of quadratic phase coupling at frequency pairs that are very close to each other. It was found that some characteristics of such bispectrum are very sensitive to focal cerebral ischemia. The maximum bispectrum magnitude of EEG and the weighted center of bispectrum (WCOB) changed sensitively to the different ischemic regions and ischemic stages. The ischemic and normal regions as well as the degree of ischemia can be clearly distinguished by analyzing their bispectrum of EEG. It demonstrates that this method can be used as a quantitative method for the detection of focal cerebral ischemia in the early phase.

[Studies on trigonometric transform enhancement of chest radiograph based on its anatomical feature]

In this paper, we present a novel trigonometric transform contrast enhancement method for digital chest radiograph, which is based on the anatomical feature of the image processed. With automatic segmenting chest image into a lung region and a non-chest region, a positive linear transform and a negative one are used in lung region and the other region respectively. Therefore, it can enhance the contrast both in lung regions and in mediastinum region up to entire dynamic range of display device.

A polarized salivary cell monolayer useful for studying transepithelial fluid movement in vitro

There are no reported, convenient in vitro models for studying polarized functions in salivary epithelial cells. Accordingly, we examined three often-used salivary cell lines for their ability to form a polarized monolayer on permeable, collagen-coated polycarbonate filters. Only the SMIE line, derived from rat submandibular gland, had this ability. The SMIE cell monolayer exhibited junctional complexes, with a tight-junction-associated protein, ZO-1, localized to cell-cell contact areas. The Na+/K+-ATPase alpha1-subunit was detected predominantly in the basolateral membranes, while the Na+/H+ exchanger isoform 2 appeared primarily in the apical membranes. Using adenovirus-mediated cDNA transfer, SMIE cells were shown to be capable of routing marker proteins (beta-galactosidase +/- a nuclear targeting signal, alpha1-antitrypsin, aquaporin-1) to appropriate locations. Furthermore, this salivary cell monolayer provided a convenient tool for studying aquaporin-1-mediated, osmotically directed, transepithelial fluid movement in vitro. Thus, SMIE cells appear to be a useful experimental model with which to study some polarized functions in a salivary epithelial cell line.

Differential regulation of Pyk2 and focal adhesion kinase (FAK). The C-terminal domain of FAK confers response to cell adhesion

Pyk2 is a recently described cytoplasmic tyrosine kinase that is related to focal adhesion kinase (FAK) and can be activated by a variety of stimuli that elevate intracellular calcium. In this report, we showed that Pyk2 and FAK tyrosine phosphorylation are regulated differentially by integrin-mediated cell adhesion and soluble factors both in rat aortic smooth muscle cells, which express endogenous Pyk2 and FAK, and in transfected Chinese hamster ovary cells. We also found that Pyk2 is diffusely present throughout the cytoplasm, while FAK is localized in focal contacts as expected, suggesting that the different localization may account for their differential regulation. By analyzing a chimeric protein contain N-terminal and kinase domains of Pyk2 and C-terminal domain of FAK, we provided evidence that the distinctive C-terminal domains of Pyk2 and FAK were responsible for their differential regulation by integrins and soluble stimuli as well as their subcellular localization. Finally, we correlated FAK, Pyk2, and the chimeric protein binding to talin, but not paxillin, with their regulation by integrins and focal contact localization. These results demonstrate that the distinctive C-terminal domain of Pyk2 and FAK confer their differential regulation by different subcellular localization and association with the cytoskeletal protein talin.

Renal angiomyolipoma: diagnosis with B-ultrasonography, CT scanning, DSA and its interventional treatment

From 1989, 15 cases of renal angiomyolipoma (AML) have been diagnosed by ultrasonography. CT scanning and digital subtraction angiography (DSA) at our hospital. In 8 patients with uneven hyperechoes on B-mode ultrasonography (B-US) (8/15) and 7 with low density of fat on CT scanning (7/12) accurate diagnosis was established preoperatively. DSA revealed the "berry-like" pseudoaneurysms in the arterial phase (14 cases), the defined lucent area in the nephrogram phase (10 cases) and the "onion-peel appearances" during venous phases (8 cases), correct diagnosis was achieved in all patients. 8 cases were surgically treated and 7 treated by subselective embolization of renal artery. Effects in all cases were good. The diagnostic value of B-US, CT scanning, DSA and interventional treatment of AML was discussed. It was believed that the diagnosis with DSA was a technique with high specificity, and embolization therapy was simple and effective for AML.

[Doppler echocardiographic studies on the fetal cardiac function in intrauterine growth retardation]

OBJECTIVE

To assess fetal cardiac function by Doppler echocardiography in intrauterine growth retardation (IUGR).

METHODS

We investigated the changes in cardiac function in 64 normal fetuses and 36 fetuses with IUGR. Blood flow velocity waveforms were obtained from the aorta, pulmonary artery and atrioventricular valves. The following variables were measured: peak flow velocity (PFV), mean velocity (V), accelerate time (ACT), systolic volume (SV) and cardiac output (CO) represented the systolic function; the peak early flow velocity (PFVe), peak late flow velocity (PFVa), PFVe/PFVa (E/A), mean velocity (V) of mitral or tricuspid valve represented the diastolic function.

RESULTS

In normal fetuses, the PFV, V, ACT of aorta were all greater than those of pulmonary artery, whereas SV, CO in left ventricle were smaller. The PFVe, PFVa in mitral valve were smaller than those of tricuspid valve. In IUGR fetuses, the PFV, V, SV, CO of aorta or pulmonary artery were significantly lower than those of normal. The ACT in pulmonary artery decreased significantly, but increased in aortic artery. The SV, Co of left ventricle were greater than those of righ ventricle. The E/A of mitral and tricuspid valve, PFVe, PFVa, V of tricuspid valve were all decreased. The PFVe, PFVa in mitral valve were greater than those of tricuspid valve.

CONCLUSIONS

The changes of cardiac function in IUGR are probably caused by "brain sparing", which means a redistribution of cardiac flow after hypoxia.

[Comparative study on the long-term effect of permanent embolization of hepatic artery with Bletilla striata in patients with primary liver cancer]

From May, 1990 to Sept., 1993 106 cases of primary liver cancer were treated by temporary or permanent hepatic arterial embolization with Bletilla striata powders (permanent, 56 cases) or gelfoam powders (temporary, 50 cases) under controlled technical conditions, in term of degree of tumor necrosis, revascularization of tumor, and long-term effect, the results of Bletilla striata group were better as compared with those of gelfoam group. The 1, 2 and 3 year survival rates were 44.9%, 33.6% and 33.6% in Beltilla striata group while the rates were 48.9%, 31.1% and 16.0% in gelfoam group, suggesting that Bletilla striata is superior to gelfoam as an embolizing agent for hepatic carcinoma.

[Pharmacognostical identification of Anoectochilus roxburghii]

This paper reported the pharmacognostical identification on characters, microscopic characteristics and TLC of the Anoectochilus roxburghii (Wall.) Lindl., and compared with different resouce samples. The results may provide reference for its identification.

[An experimental study on regeneration device for urine and waste water in space station]

The principle, structure and function of the regeneration system for urine and waste water treatment were introduced. The experimental results demonstrated that, the treatment capacity was 1.2-1.9 kg/h, and the regeneration efficiency exceeded 92%. The quality of the treated water were: TOC < 20 g/m3, (NH3 + NH4+) < 10 g/m3, electric conductivity < 100 micro s/cm, pH= 6-8.

Modulation of dimerization by residues distant from the interface in bovine neurophysin-II

The crystal structure of bovine neurophysin-II in its liganded state (Chen et al. [1991] Proc. Natl. Acad. Sci. USA 88, 4240-4244) indicates that the 1-6 sequence has a disordered conformation, lacks noncovalent contacts to other regions of the protein and is distant from the monomer-monomer interface. Cleavage of the 1-6 sequence by Staphylococcus protease V8 yielded a protein that, for the first time, crystallized in both liganded and unliganded states. Insights into the role of the 1-6 sequence in the unliganded state were obtained by NMR and related biophysical comparisons of the native and des-1-6 proteins. NMR spectra demonstrated that the environment and/or conformation of residues in the 1-6 sequence differed in liganded and unliganded states. Additionally, the unliganded des-1-6 protein exhibited a dimerization constant four to five times that of the native protein, potentially accounting for the observation that its peptide affinity was also increased. NMR studies further indicated that the increased dimerization constant of the des-1-6 protein correlated with the presence in the native protein of two isoenergetic forms of the monomer, in contrast to only a single form in the des-1-6 protein, as evidenced by signals from an internal dimerization-sensitive alpha-proton. Thus, the 1-6 sequence reduces the dimerization constant by stabilization of an alternative monomer conformation. A second product of Staphylococcus protease V8 digestion of the native protein was identified as the des-1-6 protein with an internal clip after binding site residue Glu-47, the clip presumably breaking the short 3,10 helix that most directly connects the interface to the interface to the binding site. This product, although unable to bind peptide, retained the dimerization constant of the des-1-6 protein, suggesting a lack of importance of the helix in dimerization and contrasting with the effects of the 1-6 sequence. A model is proposed in which the 1-6 sequence stabilizes the second conformation of the unliganded monomer via interactions affecting the loop region that separates the two neurophysin domains and which has been shown to influence neurophysin self-association.

[Factors for postoperative persistent hypertension in patients with aldosterone-producing adenoma]

We determined the factors for postoperative persistent hypertension in the patients with aldosterone-producing adrenal adenoma (APA) in 53 patients with APA who were followed up for average 3.1 years. All had normal serum potassium concentration postoperatively. Blood pressure was normal in 37 patients (69.8%) but 18.7/12.7 kPa or more in 16 patients (30.2%) with persistent hypertension. Also compared were sex, age, history of hypertension, effect of reducing blood pressure to antisterone, preoperative blood pressure, time of persistent hypertension, serum potassium concentration, aldosterone concentration in 24 hour urine, amount of PRA, and the type of operation. The results showed that an APA patient aged 50 years or more appears to have a great chance of persistent hypertension than an APA patient under age of 40 years, and the odds ratio is 3:1. There was a significant difference between the mean age for persistent hypertension and for normal blood pressure, and varioas response of reducing blood pressure to antisterone (P < 0.05). It is suggested that for an older APA patient and the patient without of reducing blood pressure to antisterone, there are other factors for hypertension such as renal veinlet change or renal interstitial lesions except for hyperaldosteronism. We recommend renal biopsy (using kidney puncture) at the operating table for those patients in order to understand pathological change and guide treatment after operation.

[A new type of reference electrode tube for dynamic monitoring of the acidity in digestive tract]

A new soft Ag-AgCl electrode tube is introduced in this paper. The character test and clinical application show it is especially suitable for dynamic monitoring of the acidity in upper digestive tract.

[Control of blood flow in nasal mucosa by electro-stimulation of sphenopalatine ganglion]

The effects of control of blood flow on cat nasal mucosa by stimulating sphenopalatine ganglion (SPG) were studied using laser Doppler flowmetry in order to investigate the role of SPG. The study showed that the stimulation on one side of SPG could induce vasodilation, with increased blood flow, as well as protective reflexes on both sides. The reactivity depended on the stimulation intensity, frequency and duration. The stimulation on one side of postganglionic parasympathetic nerves, in which the stellate ganglion was resected, caused vasodilation only ipsilaterally. The results indicated that the vasodilation induced by stimulating SPG might be mediated via central reflex arc. The "reverse blood regulation" phenomenon was observed during stimulation of SPG as well. The mechanisms of "reverse blood regulation" induced by stimulating SPG need further investigation.

[The development of long-term dynamic multi-parameter monitoring and analyzing system for upper digestive tract]

A long-term dynamic multi-parameter monitoring and analyzing system for upper digestive tract is presented. The system can record 24-hour pH values of the esophagus and stomach, and necessary ECG data by pressing event key. Hardware and software is described in the paper.

[Measuring EEG complexity for studying the state of mental load]

The complexity defined by Lemple and Ziv (1976) represents the degree of the sequence randomness. In this paper, the complexity of EEG under different mental loads was measured and the relation between the brain active state and the EEG complexity was analyzed. The results showed a statistically strong relation between the mental load and the EEG complexity. Further study showed that the heavier the mental load was the smaller the EEG complexity became. This correlation was especially apparent in the frontal lobe, and the complexity of EEG might be regarded as one of the parameters representing the functional state of the brain. The results indicate that EEG complexity represents the active state of brain in processing information, and the measurement of EEG complexity may provide a new path to the research in the advanced cognitive function of the human brain.

[Materials for joint replacement and friction and wear]

Debilitating diseases such as osteo- and rheumatoid arthritis, trauma and bone cancer can be treated by using prostheses. The wear resistance of materials for joint replacement can affect the service-quality and service-life of prostheses. Materials for joint replacement and friction and wear were briefly reviewed in this paper.

Relations between nasopharyngeal carcinoma and magnesium and other alkaline earth elements in soils in China

Comparison of maps shows a striking geographical relation between high mortality rates from nasopharyngeal cancer in China and low contents of magnesium, calcium and strontium in the soil. We suggest that deficiencies of these elements in the soil could be indirect markers of aetiological factors, e.g. inhalable carcinogens of local natural origin. A search for such factors could be fruitful in further studies of environmental factors in the aetiology of nasopharyngeal carcinoma.

[A fast iterative algorithm for adaptive histogram equalization]

In this paper, we propose an iterative algorthm called FAHE., which is based on the relativity between the current local histogram and the one before the sliding window moving. Comparing with the basic AHE, the computing time of FAHE is decreased from 5 hours to 4 minutes on a 486dx/33 compatible computer, when using a 65 x 65 sliding window for a 512 x 512 with 8 bits gray-level range.