Mesoscopic Conductors and Correlations in Laser Speckle Patterns

Submicrometer disordered metallic systems at low temperatures display interesting conductance fluctuation effects, owing to the interference of coherent electron wave transmission through the system. This quantum interference phenomenon also gives rise to the striking experimental observation that the 1/f noise power (where f is frequency) in disordered conductors increases as the temperature is decreased, contrary to common intuition. The theoretical techniques developed for this problem can be applied to the transmission of light through a random medium, and this yields novel predictions for the correlations in the laser speckle patterns and the possibility of studying the positions and motions of scatterers in a medium which multiply scatter the probing light.

[Estrogen receptor content of peripheral blood lymphocytes in patients with systemic lupus erythematosus]

ER content in lymphocytes of peripheral blood from 27 SLE patients and 20 healthy controls were determined by dextran-coated charcoal assay. ER content in lymphocytes of each sample was expressed by both fmol/mg of lymphocyte cytosolic protein and fmol/micrograms of lymphocyte DNA. The results showed that there was no significant difference between the ER content of lymphocytes from the controls and that from patients with SLE. But the logarithmic mean of ER content in lymphocytes, expressed by fmol/mg of cytosolic protein, in 14 patients with active SLE (0.9356 +/- 0.31) was significantly higher than that in 13 patients with inactive SLE (0.2979 +/- 0.23, P less than 0.001) and in the controls (0.6204 +/- 0.52, P less than 0.001). The normal upper limit of ER content in lymphocytes, expressed by fmol/micrograms of DNA, was 0.136. The elevated rate of ER content in lymphocytes in 14 active SLE (92.9%) was also higher than that in quieiescent patients (23.1%, P less than 0.001) and in the controls (10%, P less than 0.001). Moreover, the elevated level of ER content was found to be related to the positive antidsDNA antibody and hypocomplementemia.

[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.

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.

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)

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.

Concanavalin A receptor ‘tipping’ in Tetrahymena and its relationship to cell adhesion during conjugation

Shortly after mixing cells of complementary mating types of Tetrahymena, the cells develop the ability to pair, a process inhibited by ConA, and the region joining the cells becomes ringed with ConA receptors. This study examines the arrival of ConA receptors at the conjugation junction by looking at cells in the period between mixing and pairing. By brief incubations with F-ConA at intervals after mixing, it was ascertained that some cells had fluorescent tips as early as 15min. A kinetic analysis revealed that ‘tipping’ occurs in a manner that appears to be related to subsequent cell pairing. Cytoskeletal frameworks (CFs) were isolated under conditions in which ConA receptors remain attached. Western blot analysis of these structures revealed four major and several minor ConA-binding proteins. However, between mixing and the establishment of over 80% paired cells, changes occurring in the banding pattern were slight. This indicates that new populations of ConA receptors are not produced to any great extent after mixing. Head- on examination of CFs showed that it was possible to monitor simultaneously the process of tip transformation (widening of the nonciliated area of the tip) and ConA-receptor localization. ConA receptors originate posterior to the tip, begin to occupy the surface of the tip in clusters as the tip widens and eventually coat the transformed tip. Finally, as cells join pairs, the receptors relocate to a ring around the conjugation junction. These data suggest that ConA receptors accumulate at the anterior tips and then concentrate at the edge of the junction. This could provide a mechanism for controlling cell-cell adhesion.