Biomedical subjects
Publications and source records attributed to H Du.
Vitreous surgery was used to remove macular epiretinal membranes in 15 eyes of 15 cases of which 7 were idiopathic and 8 secondary. In the period of postoperative follow-up, the visual acuity improved in 14 eyes (93%), in which 57% improved 3 or more than 3 lines. The visual recovery is related to the time of operation chosen. No complication was noted, except development of a paracentral scotoma in 1 eye.
Varying CMAP results with changing coil location during magnetic stimulation of facial nerve have been noted in the literature. In order to investigate parameters for clinical application, 20 normal subjects were tested with Magstim Model 200 Magnetic Stimulator synchronized with Nicolet Viking II with 9 designed points of coil location at the parietal-occipital-temporal area. The amplitude and latency were recorded and analyzed statistically. Results demonstrated that the maximal amplitude was mainly obtained from following 3 points: C (midpoint between vertex and external auditory canal), V-2 (2 cm inferior to C) and H-2 (2 cm posterior to C), which showed the best location of coil for magnetic stimulation among the tested points. The maximal amplitude was also observed in points of H-4 (4 cm posterior to C) and V+2 (2 cm superior to C) in 4 subjects. In contrast to the varying amplitude, latency obtained from each stimulating point was constant, so we postulate that the same segment of facial nerve was excited regardless of moving magnetic coil around those points.
Earlier in vitro studies identified USF as a cellular factor which activates the adenovirus major late (Ad-ML) promoter by binding to an E-box motif located at position -60 with respect to the cap site. Purified USF contains 44 and 43 kDa polypeptides, and the latter was found (by cDNA cloning) to be a helix-loop-helix protein. In this report, we demonstrate a 25-to 30-fold stimulation of transcription via an upstream binding site by ectopic expression of the 43 kDa form of USF (USF43) in transient transfection assays. More recent data have also revealed alternate interactions of USF43 at pyrimidine-rich (consensus YYAYTCYY) initiator (Inr) elements present in a variety of core promoters. In agreement with this observation, we show here that USF43 can recognize the initiator elements of the HIV-1 promoter, as well as those in the Ad-ML promoter, and that ectopic expression of USF43 can stimulate markedly the corresponding core promoters (TATA and initiator elements) when analyzed in transient co-transfection assays. Mutations in either Inr 1 or Inr 2 reduced the USF43-dependent transcription activity in vivo. In addition, in vitro transcription assays showed that mutations in either or both of the Inr 1 and Inr 2 sequences of the HIV-1 and Ad-ML promoters could affect transcription efficiency, but not the position of the transcriptional start site. These results indicate that USF43 can stimulate transcription through initiator elements in two viral promoters, although the exact mechanism and physiological significance of this effect remain unclear.
The expression of genes encoding self-incompatibility ribonucleases (S-RNases) in Nicotiana alata were examined at both protein and RNA level for organ specificity. S-RNases recovered from stigmas and styles were indistinguishable by SDS-PAGE, chromatographic behaviour and RNase specific activity. The pistil S transcripts are heterogeneous in size, the stigma transcript being shorter and more heterogeneous than the transcripts in the style and ovary. RNase H analysis shows that this organ-specific difference is mainly in the length of the polyadenylate tail. By sequence analysis of cloned cDNAs we show that the transcript present in the stigma is derived from the same gene as the transcript in the style.
In the solanaceous plant Nicotiana alata, self-incompatibility is controlled by a single, multiallelic locus (S locus) expressed in both pollen and pistil. Previously, we have shown cosegregation between alleles of the S locus and alleles of a gene that encodes a glycoprotein with ribonuclease activity (S-RNase). Furthermore, expression of the S-RNase gene is apparently confined to the pistil and is correlated with the onset of self-incompatibility. In this paper, we report that the S-RNase gene is also expressed at low levels in developing pollen. A transcript in developing pollen hybridized to a cDNA encoding the S2-RNase allele of the parent plant and did not hybridize to cDNAs encoding other S-RNase alleles. Two cDNAs for the S2-RNase were cloned from a library derived from anthers of a plant homozygous for the S2 allele and both corresponded to the coding sequence of the S2-RNase. The product of the S-RNase gene was detected by immunocytochemistry in the intine of mature, hydrated pollen grains. These results are interpreted in the light of current knowledge of the structure of the S locus.
Six touch receptor neurons with distinctive morphological features sense gentle touch in Caenorhabditis elegans. Previous studies have identified three genes (lin-32, unc-86 and mec-3) that regulate touch cell development. However, since other cell types also require these genes, we suspected that other genes help restrict the expression of touch cell characteristics to the six neurons seen in the wild type. To identify such genes, we have examined mutants defective in genes required for the development of other C. elegans cells for changes in the pattern of touch cell-specific features. Mutations in seven genes either reduce (lin-14) or increase (lin-4, egl-44, egl-46, sem-4, ced-3 and ced-4) the number of touch receptor-like cells. The combinatorial action of these genes, all of which are required for the production of many cell types, restrict the number of cells expressing touch receptor characteristics in wild-type animals by acting as positive and negative regulators and by removing cells by programmed cell death.
Ophthalmoscopic and histopathologic studies of endolaser photocoagulation after vitrectomy were carried out on rabbit's eyes. The endoprobe was connected to the Coherent "Novus 2,000" argon laser system. Under appropriate application the grayish white retinal lesions produced by argon green and argon all wavelength endolaser photocoagulation were similar ophthalmoscopically at a treatment power of 80-100 mw and exposure duration of 0.2s. Histopathologically, the characteristic changes of the retinal lesions produced by argon all wave-length were more significant than that produced by argon green endolaser photocoagulation. Scattered retinal photocoagulation can be done when the opaque medium is cleared on the operating table.
A clinical research on the diabetic retinopathy(DR) is reported. In the 662 cases of diabetes mellitus examined, the prevalence of DR was 51.3%, of which 7.6% were preproliferative and 7% proliferative. The study showed that when the disease progressed to the preproliferative and proliferative DR, laser photocoagulation could be the best treatment of choice, and panretinal photocoagulation was also quite effective in the treatment of pregnant patients with proliferative diabetic retinopathy.
In this paper, the contents of catalpol, water-extract and alcohol-extract materials, ash, total reducing sugar and inorganic elements in Dihuang from different habitats have been measured. The result shows that Huai Dihuang, the genuine drug, excels all those from other habitats in quality. The quality of commercial dry Dihuang may be related closely to the production area, storage time, etc.
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Lipid emulsions consisting of a surface monolayer of phospholipid enclosing a core of neutral lipids have been prepared by repeated extrusion through polycarbonate filters of defined pore size. Particle size, as measured by photon correlation spectroscopy, decreases on successive passes through a 100 nm filter, reaching a near constant value (130-150 nm) after 4 passes. A corresponding decrease in the standard deviation of the particle size distribution occurs during this process. The recovery of lipids, especially of cholesterol and cholesterol ester, is improved if the emulsion is sonicated before extrusion through filters. [31P]-NMR and fluorescence techniques are used to confirm that the resulting structures are emulsions rather than lipid bilayers.
The lungs and thymus of mice received X-ray irradiation on the right thorax were observed. It was found that lung injury was lighter and got recovered more rapidly in mice given Salvia miltiorrhiza than that in the control group. Microscopic thymus changes showed no difference in the two groups. The results indicated that Salvia miltiorrhiza could prevent radiation-induced pulmonary injury, but could not prevent thymus injury.
N1, P2 and P300 potentials were studied in 20 cases of cerebral infarction and 47 healthy controls with the standard technique of auditory event-related potentials. Healthy controls of both sexes, different ages, education levels and cognitive capacity did not show apparent differences in the latency of P300 (P greater than 0.05, respectively). The patient group, however, revealed a significant (P less than 0.001) prolongation of latency of P300 (means = 409.6 +/- 50 ms) as compared with 28 well matched healthy subjects (means = 337.7 +/- 24 ms). Although there was a slightly lower amplitude of P300 in the patient group, the difference between control and patient groups was not significant (P greater than 0.05). There was a significant difference in the Cognitive Capacity Screening Examination findings between control and patient groups (P less than 0.01), but it seems that evaluation of the cognition-related latency of P300 may be more objective and sensitive in distinguishing between organic and cognitive distress (P less than 0.001).
We described a strategy which facilitates the identification of cell mutants which are restricted in DNA synthesis in a temperature-dependent manner. A collection of over 200 cell mutants temperature-sensitive for growth was isolated in established Chinese hamster cell lines (CHO and V79) by a variety of selective and nonselective techniques. Approximately 10% of these mutants were identified as ts DNA- based on differential inhibition of macromolecular synthesis at the restrictive temperature (39 degrees C) as assessed by incorporation of [3H]thymidine and [35S]methionine. Nine such mutants, selected for further study, demonstrated rapid shutoff of DNA replication at 39 degrees C. Infections with two classes of DNA viruses extensively dependent on host-cell functions for their replication were used to distinguish defects in DNA synthesis itself from those predominantly affecting other aspects of DNA replication. All cell mutants supported human adenovirus type 2 (Ad2) and mouse polyomavirus DNA synthesis at the permissive temperature. Five of the nine mutants (JB3-B, JB3-O, JB7-K, JB8-D, and JB11-J) restricted polyomavirus DNA replication upon transfection with viral sequences at 33 degrees C and subsequent shift to 39 degrees C either before or after the onset of viral DNA synthesis. Only one of these mutants (JB3-B) also restricted Ad2 DNA synthesis after virion infection under comparable conditions. No mutant was both restrictive for Ad2 and permissive for polyomavirus DNA synthesis at 39 degrees C. The differential effect of these cell mutants on viral DNA synthesis is expected to assist subsequent definition of the biochemical defect responsible.
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