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Biomedical subjects

S Feng

Publications and source records attributed to S Feng.

At least 199 records · Page 11Linked to original sources
PubMed1990

[Electron microscopic observation of the effects of Rhodiola kirilowii (Regel.) Maxim. in preventing damage of the rat viscera by a hypoxic high altitude environment].

This paper has shown that the pathologic damages done to rat's viscera due to hypoxic environment of altitude can be reduced significantly by oral administrations of Shengmaiyin, Danshen-Chuanxiong mixture and Rhodiola kirilowii. Shengmaiyin that maintains interior substances in the plate layer bodies proves more effective than Danshen-Chuanxiong mixture, while the latter excels in preventing capillary contraction, thus improving blood circulation. Rhodiola kirilowii has the effects of both Shengmaiyin and Danshen-Chuanxiong mixtures.

Altitude Sickness↗
PubMed1989

Diagnosis of arteriosclerosis obliterans by impedance technique with special reference to relative blood flow of the lower extremity.

Simultaneous recordings of impedance cardiography of the chest and impedance plethysmography of the lower extremity were performed on 105 limbs with or without arteriosclerosis obliterans (ASO) documented by angiography. The ratios of blood flow to the lower extremity--leg stroke volume/cardiac stroke volume--(LSV/CSV) were 11.2 +/- 3.3% in normal male subjects, 11.1 +/- 5.5% in normal female subjects, and 3.1 +/- 1.2% in lower extremities with ASO, respectively. The normal value (range) for LSV/CSV calculated from the normal groups by the percentile method was between 4.9% and 17.8%, and the diagnostic accuracy of this value was 100% for sensitivity and 97.5% for specificity. LSV/CSV is a good index for the diagnosis of ASO and makes it possible to minimize error when expressed as an absolute value.

Arteriosclerosis Obliterans↗
PubMed1988

HIV-1 tat trans-activation requires the loop sequence within tar.

Human immunodeficiency virus (HIV-1) is the primary retroviral agent responsible for AIDS and related disorders worldwide. One of its identified gene products, tat protein, stimulates in trans the expression of all HIV-1 genes by several orders of magnitude. Cells infected with HIV-1 require tat protein to produce virus, suggesting that trans-activation is crucial for viral replication. The essential cis-acting site for trans-activation, termed tar, resides within the R region of the HIV-1 long terminal repeat (LTR), between -17 and +54 with respect to the initiation site of viral transcription. It is striking that the RNA encoded between +1 and +59 has the potential to form an extensive stem-loop secondary structure which, as a portion of the untranslated leader RNA, would be common to all HIV-1 mRNAs. We now present the results of nucleotide substitution experiments which suggest that tat trans-activation requires presentation of the sequence +30CUGGG+34 in tar within the loop of a RNA hairpin structure.

DNA Mutational Analysis↗
PubMed1988

Detection of impaired left ventricular function in coronary artery disease with acceleration index in the first derivative of the transthoracic impedance change.

In order to detect impaired left ventricular (LV) function in coronary artery disease (CAD) patients using acceleration index (Ac) of impedance cardiography (ICG), exercise ICG was performed in 29 patients with chest pain but without CAD (Group 1) and 21 patients with CAD (Group 2), and their resting values were compared with 30 healthy controls (Group 3). The acceleration index, which reflects indirectly aortic blood flow acceleration, was calculated as the ratio of dZ/dtmax to its accelerating time (AT). At rest, the values for Ac in Groups 1, 2, and 3 were 23 +/- 10, 15 +/- 6, and 36 +/- 13 omega/s2, respectively. There were significant differences between Group 1 versus 3, 2 versus 3, and 1 versus 2 (all p less than 0.001). At maximal exercise, Ac showed the largest percent change among the various indices used in this study. An increase of 198% for Group 2 was markedly lower than that of 250% in Group 1 (40 +/- 14 vs. 68 +/- 24 omega/s2, p less than 0.001). With a value of less than or equal to 40 omega/s2, Ac can detect the CAD patients, with a sensitivity of 62% and specificity of 90%, superior to stress ECG using CM5 lead. It is concluded that: (1) Ac is the sole index capable of distinguishing not only between the normals and diseased groups, but also between CAD patients and suspected CAD cases at rest. (2) Ac is a remarkably sensitive index for detecting impaired LV function at maximal exercise. (3) Exercise ICG is useful for predicting CAD from the population predisposing to CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗