PubMed Health⌕ Search

Biomedical subjects

D S Zhou

Publications and source records attributed to D S Zhou.

14 recordsLinked to original sources
PubMed2001

[Interaction between protein and ciprofloxacin].

AIM: To study the interaction between ciprofloxacin and BSA in physiological condition by fluorescence spectroscopy. METHODS: The affection of drug to the protein conformation was investigated. The binding constant between drug and BSA from a double reciprocal Lineweaver-Burk plot was determined and the main sort of binding force was found according to the thermodynamic parameters. RESULTS: The binding constants between BSA and ciprofloxacin at 26 degrees C and 45 degrees C are about 10(4). At 26 degrees C, the thermodynamic parameters of reaction between BSA and ciprofloxacin are delta H = -49.13 kJ.mol-1, delta G = -26.45 kJ.mol-1, delta S = -75 kJ.mol-1. The maximum wavelength of the synchronous fluorescence spectra of BSA moved from 279 nm to 289 nm with the increasing of the amount of ciprofloxacin. CONCLUSION: There exists fluorescence energy transfer between BSA and ciprofloxacin. The main sort of binding force between BSA and ciprofloxacin is Van der Waals' interaction. Ciprofloxacin can be deposited and be transported by serum protein in vivo. Ciprofloxacin affects the protein conformation.

Anti-Infective Agents↗
PubMed1998

Immunohistochemical study of the c-kit expressing cells and connexin 43 in the guinea-pig digestive tract.

The distribution of the c-kit receptor expressing cells and gap junction protein, connexin (Cx) 43 in the guinea-pig stomach (antrum), small intestine (jejunum) and colon (ascending) was studied by immunohistochemistry. The anti-c-kit protein immunopositive cells were regularly observed in the myenteric region throughout all three organs. The immunopositive cells were also sparsely distributed in the circular muscle layer of both the stomach and the colon, but not in the small intestine. They were densely located in the regions of the deep muscular plexus (DMP) of the small intestine and submuscular plexus (SMP) of the colon. In contrast, strong immunoreactivity to anti-Cx 43 antibody was observed in almost the entire thickness of the circular muscle layer of the stomach and the small intestine, but not in the colon. Dense immunoreaction deposits were observed in the region of the DMP and SMP. However, only very weak immunoreactivity to anti-Cx 43 antibody was detected in the myenteric region of all three organs. These results suggest that the c-kit receptor expressing cells or interstitial cells of Cajal (ICC) in the myenteric region of the three organs, and in the SMP of the colon, are poorly coupled with the bulk of circular muscle tissue by gap junctions, while ICC in the DMP and in the circular muscle layer of the stomach couple well with the surrounding muscle tissue.

Animals↗
PubMed1998

Neutralizing mechanism of a monoclonal antibody against Japanese encephalitis virus glycoprotein E.

The neutralization of Japanese encephalitis virus (JEV) was studied using JEV-specific neutralizing (NT) monoclonal antibody (MAb) 503 that recognizes the envelope glycoprotein. Analysis using radiolabeled JEV and observations by confocal laser microscopy and electron microscopy indicated that the NT and protection activities of MAb 503 did not result from the prevention of the first step of JEV infection, binding of virus to the cell surface. Treatment with MAb 503 strongly inhibited JEV-induced cell fusion and internalization of JEV into the cells, and resulted in enhanced release of JEV-RNA from the cells. These observations suggested that the NT activity of MAb 503 is involved in the later steps of JEV infection.

Adsorption↗
PubMed1996

Anti-c-kit protein immunoreactive cells corresponding to the interstitial cells of Cajal in the guinea-pig small intestine.

Interstitial cells of Cajal (ICC) of the guinea-pig small intestine were studied with whole-mount preparations by using the zinc iodide-osmic acid method (ZIO) and immunohistochemistry for vimentin and c-kit receptor tyrosine kinase, and by electron microscopy. The myenteric ICC visualized with ZIO staining are immunopositive to both anti-c-kit antibody (ACK-2) and anti-vimentin antibody (V9), and constitute an independent cellular network from the myenteric plexus. Those cells are characterized by many mitochondria, abundant intermediate filaments, and surface cell membranes not covered with a basal lamina. They are connected with each other by gap junctions at tips of the cytoplasmic processes. It is concluded that the myenteric ICC of the guinea-pig intestine are fibroblast-like cells and that they correspond to the c-kit expressing cells regarded as the intestinal pacemaker.

Animals↗
PubMed1996

Neuro-muscular junctions of longitudinal and circular muscle fibers of the guinea-pig esophagus and their relation to myenteric plexus.

The structure of the neuromuscular junctions (NMJs) and their relation to the myenteric plexus were studied by zinc iodide-osmic acid (ZIO) staining and by scanning electron microscopy in the guinea-pig esophagus. The esophageal muscle coat consisted of the inner circular and outer longitudinal striated muscle fibers. The myenteric plexus was located between the two muscle layers along its whole length and was characterized by a loose and irregular network. It was demonstrated that unmyelinated nerve fibers form NMJs with the muscle fibers of both layers. The NMJs in the longitudinal muscle can be classified as 'plate' type, whereas those of the circular muscle resemble the 'grape' type. The different NMJs in the two muscle layers probably correspond to different contractile properties. The whole-mount preparations with ZIO staining also demonstrated that some NMJs receive minute branches from the myenteric plexus. Therefore, it is likely that the myenteric plexus is involved in the control of striated muscles of the guinea-pig esophagus.

Animals↗
PubMed1996

Identification of the interstitial cells of Cajal.

Observation of whole mount stretch preparations using the zinc-iodide-osmic acid method reveals a wide variety of interstitial cells in different tissue layers of the guinea-pig small intestine. And a subsequent electron-microscopic examination and survey of references makes clear that the interstitial cells of Cajal (ICC) depicted in original drawings of Cajal are heterogeneous and correspond to different types of interstitial cells. The myenteric ICC are characterized by long dichotomous branching processes which constitute cellular networks independent from the nerve plexus and form many gap junctions at their tips. Their ultrastructure is similar to that of fibroblasts and they have no basal lamina. The myenteric ICC show strong immunoreactivity for vimentin and the c-kit receptor, and probably correspond to the intestinal pacemaker cells. Within the circular muscle layer, ICC are represented by the cells that are closely associated with fine nerve bundles. The ICC have various shapes, ranging from bipolar to stellate, depending on the running pattern of the nerve fibers that they are associated with. They show fibroblast-like ultrastructure and have no basal lamina. They form gap junctions with smooth muscle cells and are immunoreactive for vimentin. On the other hand, ICC associated with the deep muscular plexus described in the guinea-pig by Cajal could not be clearly identified. However, it is suggested that the ICC in this location may correspond to glycogen-rich cells possessing a basal lamina. Although they show a fairly well-developed rough endoplasmic reticulum, Golgi apparatus and immunoreactivity for vimentin, ICC of the deep muscular plexus are probably specialized smooth muscle cells in nature.

Animals↗
PubMed1995

Ultrastructure of the zinc iodide-osmic acid stained cells in guinea pig small intestine.

This study has demonstrated that cells stained using the zinc iodide-osmic acid (ZIO) method have the same fine structural features as those of fibroblasts. They have a well developed Golgi apparatus, granular endoplasmic reticulum and many mitochondria. They have no basal lamina. They are distributed in association with the deep muscular plexus, within the outer circular muscle layer and in the space between the circular and longitudinal muscle layers. Since this staining method is believed to co-stain nerves and interstitial cells of Cajal, we concluded that these ZIO-positive, fibroblast-like cells represent at least some, if not all, of the interstitial cells which appeared in the original description by Cajal.

Animals↗
PubMed1992

The cellular network of interstitial cells associated with the deep muscular plexus of the guinea pig small intestine.

Systematic examination using electron microscopic montages and serial sections has demonstrated that three types of interstitial cell, namely gap junction-rich cells, glycogen-rich cells and fibroblast-like cells, are densely located along the whole extent of the deep muscular plexus of the guinea pig small intestine. They tend to be distributed in an alternating fashion in the cellular network, connected with muscle cells of the outer, circular layer by means of gap junctions. These three types of interstitial cell show close relations to two types of nerve varicosity: one type is characterized by clear round vesicles with diameters of about 50 nm, and the other by flattened vesicles measuring about 35 nm by 70 nm. Electron-dense patches have been observed at the cytoplasmic side of the axonal membranes. Muscle cells of both inner and outer circular layers also show close relations to these two types of nerve varicosity. These morphological features are discussed with the implication that they may have some regulatory role in intestinal movement.

Animals↗
PubMed1992

Interstitial cells associated with the deep muscular plexus of the guinea-pig small intestine, with special reference to the interstitial cells of Cajal.

Interstitial cells associated with the deep muscular plexus of the guinea-pig small intestine were studied by electron microscopy, and three-dimensional cell models were reconstructed from serial ultrathin sections with a computer graphic system. Three types of cells were recognized. The first type was similar in shape to smooth muscle cells, but did not contain an organized contractile apparatus. Many large gap junctions comprising about 4% of the cell surface were present; they connected cells of the first type to each other, to the second type of cell and to smooth muscle cells of the outer circular layer. The second type of cell had a well-demarcated cell body with long slender processes and was characterized by a large amount of glycogen comprising about 9% of the cell volume. The third type of cell was similar to fibroblasts, and contained well-developed Golgi apparatus and rough endoplasmic reticulum. Some of these fibroblast-like cells (a possible subtype) formed small gap junctions. All three types of cells showed close relationships with nerve varicosities. This cellular network consisting of gap-junction-rich cells, glycogen-rich cells and smooth muscle cells may be involved in the pacemaking activity of intestinal movement.

Animals↗
PubMed1991

[Study on risk factors involving train traffic accidents--effects of human factors on accidents].

This article analysed human factors involving train traffic accidents by using log-linear model. The results showed that lower degree of culture (OR = 2.571) and weak nervous type (OR = 2.099) were risk factors involving train traffic accidents. Interactions were shown to exist between nervous type and degree of culture, average sleeping time everyday, and visuomotor reaction time.

Accidents, Traffic↗
PubMed1991

[Epidemiological features and causes of railway traffic accidents].

This article reports on epidemiological features of railway traffic accidents and factors influencing traffic safety. An analysis of various kinds of railway traffic accidents over 30 years in Nanjing Railway Branch, Showed that railway traffic accidents have become a sort of modern social disease, and had particular epidemiological features. The peak of the epidemic curve appeared cyclically and had a close relation to social disturbances, Frequency of accident occurrence was the highest in the first season (period of spring transport) and the third season (period of high temperature) of the year thus most accidents happen in February and August. Most accidents occurred on Fridays and least on Mondays. Distribution of accidents had obvious "antenna" phenomenon in round graph which had a 24-hour cycle. Analysing the multiple factors influencing traffic safety, the results showed that the upper-limit-age of a train driver should not be more than 50 years old; The phenomenon "bathtub" between personage accident rate and age must be taken seriously. More attention should be paid to the psychological aspects when recruiting train drivers. In our country, it is urgent to set up standard of psychomovement function for choosing train locomotive drivers. Fatigue was one of the direct causes resulting in accident occurrences. No statistical correlation was found between biorhythm and accident occurrence.

Accidents, Traffic↗
PubMed1989

Studies on social medicine and leprosy in east China.

Leprosy is a disease in which the social, economic, cultural and environmental factors play an important role in occurrence, spread, control, eradication and rehabilitation. Eliminating the unfavourable factors hindering leprosy control can make achieving the goal of basic eradication of leprosy in China before the end of this century possible. For this reason, since 1984 we have carried out systematic studies of the social aspects of leprosy in Baoying County, a former high-endemic area in Jiangsu Province of East China, where the endemicity of leprosy is nearing full control.

Adolescent↗