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Biomedical subjects

S M Li

Publications and source records attributed to S M Li.

At least 19 recordsLinked to original sources
PubMed1996

Effects of long-term administration of octreotide in portal vein-stenosed rats.

The hemodynamic effects of long-term administration of octreotide in portal hypertension has not been established. In addition, whether long-term octreotide treatment prevents the development of portosystemic shunts has not yet been evaluated. Hence, the current study was undertaken to evaluate the effects of long-term administration of octreotide in rats with portal vein stenosis. Immediately after portal vein stenosis or sham operation, rats were given either a long-term octreotide administration of 100 micrograms/kg or a placebo every 12 hours by subcutaneous injection for 14 consecutive days. Systemic hemodynamics and regional blood flows, degree of mesenteric-systemic shunts, and plasma glucagon concentrations were measured after the final dose of octreotide or placebo. A fifth group of portal vein-stenosed rats received hemodynamic and plasma glucagon measurements after 1-day octreotide treatment given at 14 days after surgery. Long-term octreotide treatment modified the hyperdynamic circulation without affecting the degree of mesenteric-systemic shunts, and 1-day octreotide treatment decreased portal tributary blood flow without affecting the portal pressure, systemic hemodynamics, and degree of mesenteric-systemic shunts. Plasma glucagon levels were decreased in portal vein-stenosed rats receiving either long-term or 1-day octreodtide compared with rats receiving placebo. In contrast, chronic octreotide treatment did not affect any of the hemodynamic values or plasma glucagon levels in sham-operated rats. In conclusion, long-term administration of octreotide modified in part the development of portal hypertension and hyperdynamic circulation in portal vein-stenosed rats without affecting the degree of mesenteric-systemic shunts.

Analysis of Variance↗
PubMed1996

Hyperglucagonaemia in cirrhotic patients and its relationship to the severity of cirrhosis and haemodynamic values.

Plasma glucagon concentrations were measured in 160 cirrhotic patients (Pugh's grade A in 52 patients, Pugh's grade B in 64 patients and Pugh's grade C in 44 patients). These values were compared with plasma glucagon concentrations in 57 age and sex-matched healthy subjects. Systemic and portal haemodynamic measurements, effective renal plasma flow and creatinine clearance were recorded for each patient. Plasma glucagon levels were significantly increased in cirrhotic patients compared with healthy subjects. In addition, plasma glucagon levels were higher in cirrhotic patients with ascites than in those without ascites and were increased in relation to the severity of cirrhosis as assessed by Pugh's score. Multiple linear regression found that only Child-Pugh's score was estimated to be an independent predictor of hyperglucagonaemia in cirrhotic patients. However, in patients with different degrees of oesophageal varices and in patients without oesophageal varices, plasma glucagon concentrations were no different among the different groups of patients, but were still higher than plasma glucagon concentrations in healthy subjects. In contrast, plasma glucagon levels were negatively correlated with mean arterial pressure and systemic vascular resistance. The results of the present study suggest that impairment of liver function plays, in part, a role in increased plasma glucagon levels observed in patients with cirrhosis. In addition, these data support the hypothesis that hyperglucagonaemia may contribute, at least in part, to the pathogenesis of peripheral arterial vasodilatation in cirrhosis with portal hypertension.

Adult↗
PubMed1996

Screening of microorganisms for biodegradation of poly(lactic-acid) and lactic acid-containing polymers.

The ability of some microorganisms to use lactic acid stereocopolymers and copolymers with glycolic acid as sole carbon and energy sources was studied under controlled or natural conditions. First, 14 filamentous fungal strains were tested in liquid cultures, adopting total lactic acid consumption, nitrogen source exhaustion, and maximal biomass production as selection criteria. Two strains of Fusarium moniliforme and one strain of Penicillium roqueforti were able to totally assimilate DL-lactic acid, partially soluble racemic oligomers (MW = 1,000), and the nitrogen source. Only one strain of F. moniliforme was able to grow on a poly(lactic acid)-glycolic acid copolymer (MW = 150,000) after 2 months of incubation at 28 degrees C on synthetic agar medium. Mycelium development was examined by scanning electron microscopy. F. moniliforme filaments were observed to grow not only at the copolymer surface but also through the bulk of the copolymer. In a second approach, plates made of a racemic poly(lactic acid) were buried in the soil before being incubated in petri dishes containing mineral agar medium under controlled conditions. Five strains of different filamentous fungi were isolated, and their ability to assimilate racemic poly(lactic acid) oligomers was tested in liquid cultures.

Biodegradation, Environmental↗
PubMed1994

Attempts to map the structure and degradation characteristics of aliphatic polyesters derived from lactic and glycolic acids.

During the past 5 years, important advances have been accomplished in the understanding of the fate of aliphatic polyesters derived from lactic acid (LA) and glycolic acid (GA) in aqueous media. Hydrolysis of solid LA/GA polymers is now regarded as dependent upon a diffusion-reaction mechanism. Faster central degradation, degradation-induced composition, and morphology changes are three of the most important findings which appeared to be composition-dependent as deduced from the behavior of different LA/GA polymers. An attempt is made to generalize these findings to the whole family and to elaborate a map which could be used to predict degradation characteristics of LA/GA polymers from their initial composition and morphology.

Hydrolysis↗
PubMed1994

[Treatment of femoral trochanteric fracture with intramedullary interlocking nailing: a report of 32 cases].

We improved and made the intramedullary interlocking nail and it's instrument for surgical operation in December 1989 by consulting the reported material of the gamma locking nail. 32 cases of the femoral trochanteric fracture were treated by using this fixation system. The results were satisfactory. The patients could stand up and move about beginning from 6th to 13th day after operation. No mechanical failure of implant, infection and other complications occurred in our series. 29 cases were followed-up for 5 to 19 months and showed all of the fractures were healed. Their hip functions were completely or basically recovered. Coxa vara deformity occurred in two cases and one had a 2.5 cm shortening of the lower limb. We consider that the intramedullary interlocking nail conforms to the principle of human biomechanics and it may be used as an effective surgical treatment with the fracture fixation of superior strength and stability for every type of femoral trochanteric fractures.

Adult↗
PubMed1994

[Quantitative structure-activity relationship of P-amino-diphenyl ether analogues to inhibit cytochrome P-450].

A group of p-amino-diphenyl ether analogues were tested for their activities to prolong the pentobarbital sleeping time in mice and to inhibit the demethylation of p-nitro-anisole catalyzed by untreated mouse hepatic microsomes in vitro. The stepwise multiple regression analyses were used to obtain the quantitative structure-activity relationships between the activities of inhibiting cytochrome P-450 in vitro or in vivo for the analogues and their quantum chemical indexes. The results showed that the inhibiting activities both in vitro and in vivo were correlated with the energy level of the lowest unoccupied molecular orbital (ELUMO), the nucleophilic superdelocalizabilities of the nitrogen (SN(N)) and the oxygen (SN(O)). The inhibiting activities of the analogues to cytochrome P-450 may mainly come from their ability to form cytochrome P-450 metabolic intermediate complex.

Animals↗
PubMed1994

[Comprehensive treatment for diabetes limb gangrene].

Anisodamine was used to improve general circulation and the microcirculation of affected limbs. Measures like local debridement, dressing change, and control of diabetes were applied in 351 patients with diabetic limb gangrene. Of the 351 patients, 301 (85.7%) were cured, 27(7.7%) were improved, 7(2.0%) failed, 6(1.7%) had limb amputated, and 10(2.9%) died. In the treatment, the nail-fold microcirculation was markedly improved. Doppler scan showed increased width and bloodflow of the vessels of the affected limbs. The criteria for the classification and diagnosis of diabetes limb gangrene are suggested.

Adult↗
PubMed1992

Serum steroid hormonal profiles by reversed-phase liquid chromatography in patients with 17-hydroxylase deficiency and in an affected family.

We used an optimized isocratic reversed-phase high-performance liquid-chromatographic procedure to separate and measure 12 steroid hormones, and studied the steroid hormone profiles in sera from three patients with 17-hydroxylase deficiency (17-OHD). Two of the patients were sisters, one of whom (II-3), expressing normotension and primary amenorrhea, was diagnosed on the basis of chromatographic data and followed up for seven years. The untreated patients had obvious abnormalities on chromatograms of serum extracts, characterized by markedly increased corticosterone (B) and decreased or undetectable cortisol (F) and cortisone (E). The concentration of 11-deoxycorticosterone was much greater in the patient with classical symptoms than in the normotensive patient. In all three patients, concentrations of aldosterone were within the normal range, but concentrations of progesterone were much lower than in the patients with 21-hydroxylase deficiency. We evaluated the responses to corticotropin and dexamethasone. HPLC evaluation of the serum steroid profiles before and after corticotropin stimulation in the affected family showed that in the parents and one other sibling, concentrations of F before and after stimulation were within the normal ranges. The sums of the ratio of B to F before and the ratio of B to F after corticotropin stimulation (sigma B/F) in the parents and the other sibling were 0.292, 0.496, and 0.614, respectively, all much higher than the normal value (mean +/- SD: 0.164 +/- 0.038). Thus the sigma B/F value may be a hormonal marker of heterozygotes carrying this defect.

Adolescent↗
PubMed1992

[Reduction of genotoxic damage in oral mucosa with myasthenia gravis by traditional Chinese medicine].

Micronucleated exfoliated cell (MEC) of oral mucosa of 40 patients with myasthenia gravis (MG) and 54 normal controls were observed by means of micronucleus test. The frequency of MEC of two groups were 9.56/1000 and 2.55/1000 respectively, and their difference was remarkably significant (P < 0.001). 22 cases were treated by TCM Qiang Ji Jian Li Capsule. The frequency of MEC after treatment fell from 14.38/1000 to 6.00/1000. The difference was significant (P < 0.002). The frequency of Spleen-asthenia group higher than that of non-Spleen-asthenia (P < 0.05). The results revealed that. The patients with MG had genotoxic damage. (2) The constitution with the Spleen-asthenia and the genotoxic damage was related. (3) Qiang Ji Jian Li Capsule of invigorating the Spleen and benefiting Qi could reduce the genotoxic damage.

Adolescent↗
PubMed1992

Androgens and breast cancer.

We have recently demonstrated that physiological levels of androgens exert direct and potent inhibitory effects on the growth of human breast cancer ZR-75-1 cells in vivo in nude mice as well as in vitro under both basal and estrogen-stimulated conditions. The inhibitory effect of androgens has also been confirmed on the growth of dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma in the rat. Such observations are in close agreement with the clinical data showing that androgens and the androgenic compound medroxyprogesterone acetate (MPA) have beneficial effects in breast cancer in women comparable to other endocrine therapies, including tamoxifen. Although the inhibitory action of androgens on cell proliferation in estrogen-induced ZR-75-1 cells results, in part, from their suppressive effect on expression of the estrogen receptor, the androgens also exert a direct inhibitory effect independent of estrogens. Androgens cause a global slowing effect on the duration of the cell cycle. These observations support clinical data showing that androgenic compounds induce an objective remission after failure of antiestrogen therapy as well as those indicating that the antiproliferative action of androgens is additive to that of antiestrogens. We have also recently demonstrated in ZR-75-1 human breast cancer cells the antagonism between androgens and estrogens on the expression of GCDFP-15 and GCDFP-24 which are two major proteins secreted in human gross cystic disease fluid. The effects of androgens and estrogens as well as those of progestins and glucocorticoids on GCDFP-15 and GCDFP-24 mRNA levels and secretion are opposite to those induced by the same steroids on cell growth in ZR-75-1 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgens↗
PubMed1991

[Use of MMPI (Minnesota multiphasic Personality Inventory) in the evaluation of patients with chronic pain syndrome].

The MMPI was performed in 25 patients with chronic pain syndrome to evaluate the personality trait. The results showed an elevation in scales 1, 2, 3 in 64% of the patients. The inventory was effective on the assessment of patients. It offered standardization and objective visualization of patients' psychical involvement. Also, it can serve as a prognostic factor for psychotherapy and surgery.

Adolescent↗
PubMed1991

The effect of age misreporting in China on the calculation of mortality rates at very high ages.

When mortality rates by age are calculated from recorded deaths and enumerated populations, rates at higher ages are typically in error because of misstated ages. Mortality rates for China in 1981 have been calculated from the number of deaths in 1981 in each household recorded in the 1982 census, and from the census population back-projected one year. Because age was determined from date of birth, and because persons of the Chinese culture have very precise knowledge of date of birth, the mortality rates even at high ages should be unusually accurate. This expectation is fulfilled for most of China, but severe misreporting of age is found in a province that contains a large minority of a non-Han nationality, which lacks precise knowledge of date of birth. Although the province contains only 1.3% of China's population, male death rates above age 90 for all of China are distorted seriously by the erroneous data from this location.

Aged↗
PubMed1989

Inhibitory effect of androgens on DMBA-induced mammary carcinoma in the rat.

Constant release of the androgen 5 alpha-dihydrotestosterone (DHT) in ovariectomized rats bearing DMBA-induced mammary carcinoma caused a marked inhibition of tumor growth induced by 17 beta-estradiol (E2). That DHT acts through interaction with the androgen receptor is supported by the finding that simultaneous treatment with the antiandrogen Flutamide completely prevents DHT action. Particularly illustrative of the potent inhibitory effect of DHT on tumor growth are the decrease by DHT of the number of progressing tumors from 69.2% to 29.2% in E2-treated animals and the increase by DHT of the number of complete responses (disappearance of palpable tumors) from 11.5% to 33.3% in the same groups of animals. The number of new tumors appearing during the 28-day observation period in E2-treated animals decreased from 1.5 +/- 0.3 to 0.7 +/- 0.2 per rat during treatment with DHT, an effect which was also reversed by the antiandrogen Flutamide. The present data demonstrate, for the first time, that androgens are potent inhibitors of DMBA-induced mammary carcinoma growth by an action independent of inhibition of gonadotropin secretion, and suggest an action exerted directly at the tumor level.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

Mortality decline and Chinese family structure: implications for old age support.

This study examined the effect of mortality change on the probabilities of survival for various family members and parent/child joint life expectation in Chinese mainland and Taiwan during the past 60 years. Major increases in life expectancy have led to the doubling of the average number of person years of an individual's life spent as a grandparent during that time. In a sense, the family burden of old age support is twice as much as before. It is concluded that the role of family in providing old age support needs to be complemented and reinforced by public programs.

Adult↗
PubMed1988

Human exposure to carbon monoxide and inhalable particulate in Beijing, China.

Twenty nonsmoking volunteers were selected from the staff members of the Institute of Health according to their housing conditions. Carbon monoxide (CO) and particulate matter in the outdoor and indoor air and personal exposure were monitored simultaneously for 1 week in summer and 1 week in winter. At the same time some public areas, such as workplaces and shopping and traffic areas, were also monitored. The average outdoor concentration for CO was 1.5 ppm in summer and 3.9 ppm in winter; indoors it averaged 2.8 ppm in summer and 20.1 ppm in winter. Personal exposure fluctuated between these values. The level of COHb averaged 0.2% in summer and 1.9% in winter. The level of inhalable particles was higher in winter than in summer, but the difference was not as marked as that for CO. The activity diary showed that the time spent at home was around 66% and that total indoor (home and workplace) time was over 90%. This indicates the importance of studying indoor pollution and personal exposure.

Adult↗
PubMed1988

Analysis of organic and inorganic components of inhalable particles in the atmosphere.

Samples of total suspended particulate matter and inhalable particles were collected from the atmosphere in Beijing, Shanghai, Wuhan, Taiyuan, and Zibo. The size distribution of particles, the variations in their concentrations during different seasons, and the concentrations of 10 kinds of inorganic elements and polycyclic aromatic hydrocarbons were also obtained. This information provided a scientific basis for studying the effects of particle pollution on human health, for formulating health standards, and for taking preventive measures.

Air Pollutants↗