Biomedical subjects

A G Li

Publications and source records attributed to A G Li.

6 recordsLinked to original sources

PubMed2006

Comprehensive study of lead pollution in Shanghai by multiple techniques.

Aerosol samples of PM10 particulates were examined with particle-induced X-ray emission (PIXE and micro-PIXE ), inductively coupled plasma-mass spectrometry, and X-ray absorption fine structures (XAFS) to investigate atmospheric Pb concentrations and its chemical species and to decide the source assignment. From the elemental analyses, lead concentrations were averaged at 369 and 237 ng.m-3 in aerosol samples of PM10 collected from 19 monitor sites in Shanghai in the winter of 2002 and 2003, respectively. The XAFS results show that major chemical forms of the lead particulates are probably PbCl2, PbSO4, and PbO. A calculation of isotope ratio and chemical mass balance of the PM10 samples revealed that the atmospheric lead particulates in Shanghai in the two periods were mainly from coal combustors, iron and steel plants, and automobile exhausts, with coal combustion dominating the lead pollution after the phasing out of leaded gasoline in 1997 in Shanghai.

Air Pollutants↗

PubMed2006

Hair follicle defects and squamous cell carcinoma formation in Smad4 conditional knockout mouse skin.

Smad4 is the common mediator for TGFbeta signals, which play important functions in many biological processes. To study the role of Smad4 in skin development and epidermal tumorigenesis, we disrupted this gene in skin using the Cre-loxP approach. We showed that absence of Smad4 blocked hair follicle differentiation and cycling, leading to a progressive hair loss of mutant (MT) mice. MT hair follicles exhibited diminished expression of Lef1, and increased proliferative cells in the outer root sheath. Additionally, the skin of MT mice exhibited increased proliferation of basal keratinocytes and epidermal hyperplasia. Furthermore, we provide evidence that the absence of Smad4 resulted in a block of both TGFbeta and bone morphogenetic protein (BMP) signaling pathways, including p21, a well-known cyclin-dependent kinase inhibitor. Consequently, all MT mice developed spontaneous malignant skin tumors from 3 months to 13 months of age. The majority of tumors are malignant squamous cell carcinomas. A most notable finding is that tumorigenesis is accompanied by inactivation of phosphatase and tensin homolog deleted on chromosome 10 (Pten), activation of AKT, fast proliferation and nuclear accumulation of cyclin D1. These observations revealed the essential functions of Smad4-mediated signals in repressing skin tumor formation through the TGFbeta/BMP pathway, which interacts with the Pten signaling pathway.

Alopecia↗

PubMed1998

Compared with parenteral nutrition, enteral feeding attenuates the acute phase response and improves disease severity in acute pancreatitis.

BACKGROUND: In patients with major trauma and burns, total enteral nutrition (TEN) significantly decreases the acute phase response and incidence of septic complications when compared with total parenteral nutrition (TPN). Poor outcome in acute pancreatitis is associated with a high incidence of systemic inflammatory response syndrome (SIRS) and sepsis. AIMS: To determine whether TEN can attenuate the acute phase response and improve clinical disease severity in patients with acute pancreatitis. METHODS: Glasgow score, Apache II, computed tomography (CT) scan score, C reactive protein (CRP), serum IgM antiendotoxin antibodies (EndoCAb), and total antioxidant capacity (TAC) were determined on admission in 34 patients with acute pancreatitis. Patients were stratified according to disease severity and randomised to receive either TPN or TEN for seven days and then re-evaluated. RESULTS: SIRS, sepsis, organ failure, and ITU stay, were globally improved in the enterally fed patients. The acute phase response and disease severity scores were significantly improved following enteral nutrition (CRP: 156 (117-222) to 84 (50-141), p < 0.005; APACHE II scores 8 (6-10) to 6 (4-8), p < 0.0001) without change in the CT scan scores. In parenterally fed patients these parameters did not change but there was an increase in EndoCAb antibody levels and a fall in TAC. Enterally fed patients showed no change in the level of EndoCAb antibodies and an increase in TAC. CONCLUSION: TEN moderates the acute phase response, and improves disease severity and clinical outcome despite unchanged pancreatic injury on CT scan. Reduced systemic exposure to endotoxin and reduced oxidant stress also occurred in the TEN group. Enteral feeding modulates the inflammatory and sepsis response in acute pancreatitis and is clinically beneficial.

APACHE↗

PubMed1989

[Effect of buyang huanwu decoction on the antithrombotic functions of the vessel wall].

The effects of Buyang Huanwu Decoction (BYHWD) on the antithrombotic functions of vessel wall were studied with human umbilical vein perfusion. It was observed that the both of Von Willebrand factor release stimulated by thrombin from the vessel walls and conversion of fibrinogen to fibrin catalyzed by thrombin were inhibited by BYHWD. There were no obvious effects of BYHWD on the thrombin adsorption to the vessel walls and the thrombin induced release of PGI2 as well as fibrinolysis inhibiting activity from the vessel walls.

Blood Vessels↗

PubMedDate not supplied

[Comparative study of methods of active effects on human brain to reveal abilities of low level perception].

Active methods of the influence upon the person with the aim of forming special states of the brain in order to obtain reproducible and strong perception of low level signals are compared. If the human brain is immediately exposed to the force by penetrating physical fields (i.e. magnetic, electromagnetic, acoustic) than best results can be obtained while using electromagnetic and acoustic fields; in this case the effectiveness of the tests on perception grows from (50 +/- 6) to (79 +/- 9)%. If the brain is forced through the peripheral sensory systems (visual and acoustic analyzers and skin receptors) than perception grows from (50 +/- 6) to (85 +/- 10)%. Special device for influence upon the brain through visual analyzer with the help of bylatheral photo-stimulation is described. The outlook of the control upon special states of brain with the aim to reveal abilities to the low level perception is discussed.

Acoustic Stimulation↗

PubMedDate not supplied

[A statistic approach to interpretation, results processing and hypo thesis testing in experiments on exposuring the human brain to perception of low level signals].

There are shown the limitations of using the generally accepted approaches to statistic data processing at the perception of low level signals on Bernully scheme when specific nature on the phenomenon (the human ability to perception is not constant, uncontrolled and manifests itself for a short time) isn't taken into account. A new approach to the statistic processing of measurement results is also proposed. It is based on the sequence analysis of correct answers in a series, the use of sequential statistic procedures (criteria), maximally taking into account the perception specificity and the measurement features. The estimate of first kind error in proposed method has been carried out.

Brain↗