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Biomedical subjects

D Zhang

Publications and source records attributed to D Zhang.

At least 649 records · Page 36Linked to original sources
PubMed1992

[Preliminary observation of imaging of facial temperature along meridians].

Visualization of meridians has been carried out by means of infrared thermography and radionuclide scintigraphy, but real success was hardly achieved on some special regions including facial channels. In this paper, we would represent some imagings of thermal line along channels by means of infrared thermography. Distribution of the facial temperature in 139 cases of healthy volunteers and 305 cases of patients with facial paralysis was observed with model AGA-782 infrared thermovision and TC-800 computer. In all cases of patients and 15 cases of healthy persons, acupuncture test was conducted. Special program, DISCO3.1 was used to process the thermographic data and the results were as follows: 1. Facial thermal line along channel was presented in 95 out of 444 cases. High temperature line along bladder channel appeared in 34 cases of them; 2. In 26 out of 95 cases, the thermal line appeared after acupuncture, which could improve the imaging of the line; 3. The range of the temperature was within 1.3 degrees C, in some cases only 0.2-0.3 degrees C, with +/- 0.5-1.0 degrees C difference to surrounding temperature; the width of the line was 1-1.5 cm in most cases; 4. The line could appear stably, in some cases, last for several days, weeks or months; 5. Certain relationship between the appearing of the line and facial paralysis was found. As mentioned above, the thermal characteristics of meridians in face could be visualized by means of infrared thermography, the special imaging of facial temperature along bladder meridian was easily found, related to facial troubles and promoted by acupuncture.

Acupuncture Therapy↗
PubMed1992

Research on the main elements influencing blood pressure measurement by pulse wave velocity.

There have been considerable errors in non-invasive continuous beat-by-beat blood pressure (BP) measurement using the pulse wave velocity (PWV). To solve the problem, an in vivo study using 10 dogs was performed. The PWV-BP correlation under intact neuro-humoral factors was compared with that under the factors to be partly eliminated and the PWV-BP regularities were investigated using 10-beat average data. It was confirmed that the vasomotion and the viscoelasticity of vascular smooth muscles are the main elements influencing PWV-BP correlation through changing the elasticity of the arterial wall, and result in a 'shift' and 'zigzag swings' in the PWV-BP relationship so as to lower the PWV-BP correlation. By choosing large arteries and modifying the PWV algorithm, linear correlation coefficients of 0.97 +/- 0.027 and standard errors of the BP estimate of 5.29 +/- 2.84 mm Hg were obtained. The study suggests that the error could be further reduced by simultaneously measuring some related parameters.

Animals↗
PubMed1992

The purification of a guanine nucleotide regulatory protein from rat brain membrane and the measurement of its GTPase.

A guanine nucleotide regulatory protein (G-protein) was purified to homogeneity from rat brain membrane though a series of chromatography runs, including DE-52 ion exchange, AcA-34 ultrogel, and octyl-Sepharose columns. The purified G-protein consisted of 3 subunits with molecular weights of 41000, 36000, and 8000, respectively. The alpha-subunit of the G-protein possessed high affinity GTP binding sites (k = 22.5 nmol/L) and GTPase activity (Km = 82.5 nmol/L, Vmax = 2.8 pmol/min/microgram protein), and it could be ADP-ribosylated by [adenylate-32P]-NAD in the presence of pertussis toxin. These results suggest that the purified protein was Gi-protein.

Animals↗
PubMed1992

Significance of the 56th tyrosine on cytotoxic activity of tumor necrosis factor.

After using site-specific mutagenesis a conserved amino acid residue, the 56th tyrosine in human tumor necrosis was substituted by glutamine. The expression level of the mutant protein in E. coli did not changed significantly, however, its specific activity of the cytotoxicity on L929 cultural cells was decreased to 1/583 of that of the unmutant tumor necrosis factor. The results show that the 56th tyrosine residue or the region where tyrosine 56th located is important for the cytotoxic activity of tumor necrosis factor.

Base Sequence↗
PubMed1991

Descending adrenergic input to the primate spinal cord and its possible role in modulation of spinothalamic cells.

The present study focuses on 3 different aspects of the descending adrenergic system in the primate: (1) the distribution of adrenergic fibers and terminals in the spinal cord, (2) the source of this input and (3) the possible physiological effects of this system on spinal nociceptive processing. Antibodies to the enzyme phenylethanolamine-N-methyltransferase (PNMT) were employed to map the distribution of epinephrine-containing axonal profiles in the primate spinal cord. Smooth longitudinally oriented fibers were localized to the outer edge of the lateral funiculus. PNMT-containing axonal enlargements were distributed to the superficial dorsal horn, intermediate gray matter and the region surrounding the central canal at all spinal cord levels. PNMT-immunostained profiles were also observed in the intermediolateral cell column. A double labeling study employing retrograde transport of HRP from the spinal cord and PNMT immunohistochemistry identified a small population of HRP-PNMT-labeled neurons in the 'C1' region at the levels of the medulla and ponto-medullary junction. Thus, these cells are a probable source of adrenergic input to the spinal cord. Electrophysiological studies demonstrated that iontophoresis of epinephrine onto identified primate spinothalamic tract neurons in the lumbar dorsal horn resulted in inhibition of the glutamate-induced firing of these cells. The data from these studies support the hypothesis that adrenergic (PNMT-containing) cells in the caudal brainstem project to all levels of the cord and may contribute to descending modulation of nociceptive processing at these levels.

Animals↗
PubMed1991

Histochemical studies on the mechanism of macromolecule leakage across the glomerular capillary wall. Barrier effect of the anionic groups of the capillary wall against the serum protein leakage.

For the purpose of revealing the barrier effect of the anionic groups of glomerular capillary wall against the serum protein leakage, morphologic and histochemical observations were made on the rat kidney perfused in situ with three kinds of cationic macromolecules different in chemical characteristics followed by blood flow restoration. The polyethyleneimine perfusion resulted in the complete disapperance of ionized anionic groups of glomerular capillary and the massive protein leakage through glomeruli by blood flow restoration. Cationic ferric colloid perfusion induced moderate protein leakage, and avidin perfusion was less in neutralization effect of anionic groups and the protein leakage was of least. The protein leakage from glomeruli, however, was stopped or markedly suppressed soon after the blood flow restoration by the newly formed functioning anionic barrier probably by some particular serum protein deposition. The findings indicate that the deionization of the glomerular capillary wall will not be responsible for the persistent albuminuria.

Animals↗
PubMed1991

Noradrenergic innervation of somatosensory thalamus and spinal cord.

Monoamine systems have been shown to be an important part of an endogenous analgesic system of the central nervous system. Some aspects of the anatomical basis of monoamine modulation of nociceptive input were investigated in these studies. Two sites examined where monoamine systems are known to impinge on the pain transmission system included the grey matter of the somatosensory thalamus and the spinal cord. In particular, the connections of noradrenergic systems with these regions were emphasized. In the ventral posterolateral nucleus of the thalamus the presence of a sparse innervation by both noradrenergic and serotonergic fibers was confirmed by electron microscopy. Boutons containing markers for either serotonin or norepinephrine were observed contacting dendrites and somata in this region. The origins of these projections were determined, by retrograde transport studies, to be primarily in the locus coeruleus and the dorsal raphe. Also examined was noradrenergic innervation of the spinothalamic tract neurons which relay information related to pain from the spinal cord. Some catecholamine boutons were observed to contact spinothalamic neurons directly. These included spinothalamic tract neurons of the wide dynamic range and the high threshold category. The presence of noradrenergic elements in the somatosensory thalamus and, in particular, the direct connection with spinothalamic tract neurons at the level of the spinal cord clearly provides an anatomical substrate for influencing sensory mechanisms related to pain.

Animals↗
PubMed1991

Corticotropin releasing factor-like immunoreactivity (CRF-LI) in horizontal cells of the developing rat retina.

This study describes a phenomenon of transient expression of corticotropin releasing factor-like immunoreactivity (CRF-LI) in immature horizontal cells of the developing rat retina. These cells could be distinguished from those destined to become CRF-LI amacrine cells in the adult by their location within the outer portion of the neuroblastic layer (NBL) and by their ontogenetic pattern. Upon initial detection on postnatal day 3 (PD-3), faint CRF-LI cellular profiles were found in the outer portion of the NBL, limited to the central region of the retina. Subsequently, on PD-5, these profiles began to appear in the periphery, forming a single horizontal row along the outermost aspect of the developing inner nuclear layer (INL), concomitant with the establishment of the outer plexiform layer (OPL). The results of our birth-dating study combining immunohistochemistry and [3H]-thymidine autoradiography indicated that these cells were generated between embryonic day 14 and 18. These findings are consistent with them being horizontal cells. Between PD-7 and PD-9, CRF-LI in horizontal cells began to diminish progressively following a center-to-periphery gradient such that only sporadic, faintly immunoreactive patches of cells could be seen by the time of eye opening (PD-15). Around PD-19, it declined to levels below immunohistochemical detection. However, when rats were reared in complete darkness beginning at birth until PD-21, the period of CRF-LI expression in horizontal cells was prolonged and persisted throughout the first three postnatal weeks of development.

Animals↗
PubMed1991

In vivo correlation of myocardial metabolism, perfusion, and mechanical function during increased cardiac work.

STUDY OBJECTIVE: The aim was to study the in vivo interaction and regulation of myocardial perfusion, metabolism, and pump function in an open chest canine model using a combination of potentially non-invasive and clinically useful techniques. DESIGN: To assess potential regulatory mechanisms and the interaction of myocardial perfusion, metabolism, and contractile function responses during changes in cardiac workload, noradrenaline (1 microgram.kg-1.min-1) was infused and hypoxia was produced by increasing the inspired ratio of nitrogen to oxygen to produce a PaO2 of 2.6-4.0 kPa in separate interventions. SUBJECTS: Nine mongrel dogs of either sex, age 2-5 years, weight 8.5(SD 2.2) kg, were studied in separate interventions. MEASUREMENTS AND MAIN RESULTS: Myocardial perfusion was determined using 2H nuclear magnetic resonance (NMR) measured washout of deuterium oxide from the left ventricle interpreted with a one component Kety-Schmidt exponential model. High energy phosphate bioenergetics were determined by 31P NMR measurements of the phosphocreatine/ATP ratio. Redox state was estimated by nicotinamide adenine dinucleotide fluorometry expressed as percent change from the baseline, normalised to maximum response measured at 100% inspired N2. Mechanical function was evaluated using heart rate X systolic blood pressure and oxygen consumption measurements. During both noradrenaline infusion and hypoxia, mechanical function increased significantly from control values: heart rate X systolic blood pressure = 1.9(SD 0.5), 3.6(0.1), and 2.6(0.4), respectively; oxygen consumption = 0.9(2), 1.6(0.1), and 1.2(0.6) ml.min-1.100 g-1. Myocardial perfusion increased to support the increased workloads, from 87(10) to 131(20), and from 60(12) to 182(14) ml.min-1.100 g-1, respectively. ADP, estimated by the phosphocreatine/ATP ratio, did not change during noradrenaline infusion [2.4(0.2) to 2.4(0.7)], but decreased during hypoxia [2.4(0.4) to 1.7(0.5)]. Redox state decreased during noradrenaline infusion, from 100% to 84(0.7)%, and increased during hypoxia, from 100% to 140(10)%. CONCLUSIONS: Similar changes in workload induced by different physiological stimuli are associated with different biochemical responses even though changes in perfusion are similar. The data suggest that myocardial function is regulated by different biochemical mechanisms under different physiological conditions, ie, there is probably no universal regulator of myocardial function. It is now possible to evaluate potential metabolic regulators of myocardial function in an in vivo animal model.

Animals↗
PubMed1991

In vivo mechanisms of myocardial functional stability during physiological interventions.

Metabolic regulatory mechanisms are designed to maintain stable myocardial function during extremes in physiological insult; they can now be studied in vivo and may provide insight into mechanisms of altered myocardial functional decompensation during disease processes. To determine mechanisms of myocardial stability during hypoxia and acute pressure loading, creatine kinase (CK) kinetics (forward rate constant, Kf, and flux of phosphocreatine, PCr, to adenosine triphosphate, ATP), and nicotinamide adenine dinucleotide (NADH) redox state were determined with 31P nuclear magnetic resonance (NMR) and NADH fluorometry, respectively, and correlated with heart work (heart rate x systolic blood pressure, HR x SBP), cardiac output (CO) and O2 consumption (MVO2) in 15 anesthetized open chest dogs. Hypoxia (PaO2 of 30-35 mm Hg) was produced in 6 dogs with an inspired O2/N2 of 200/3,000. Cardiac loading was produced in 9 dogs by administration of norepinephrine (NE, 1 micrograms/kg/min). Each dog acted as its own control. Baseline NADH fluorometry, 31P-NMR saturation transfer and cardiac function measurements were performed simultaneously in each dog, after which the experimental interventions were made. Similar increases in HR x SBP, CO, and MVO2 which occurred during both interventions were associated with different bioenergetic responses. During NE infusion, the Kf of CK increased from control; during hypoxia, the Kf decreased from control (p less than 0.05). Flux of PCr----ATP was significantly lower during hypoxia than during NE infusion (p less than 0.05). PCr was decreased significantly during NE infusion (p less than 0.05). In addition, NADH redox state increased (from baseline of 100%) during hypoxia (140 +/- 10%) and decreased during NE infusion (78 +/- 6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1991

Anticardiolipin antibodies: a study of frequency in TIA and stroke.

We undertook a prospective study of consecutive patients to determine the frequency of elevated IgG and IgM anticardiolipin antibodies in transient ischemic attack and ischemic stroke and found elevated IgG antibodies in 8.2% (9 of 110) and IgM in 9.1% (10 of 110), only the former being significantly greater than in a healthy control population. We suggest that anticardiolipin screening be concentrated on the young.

Antibodies↗
PubMed1991

Reproductive performance of artificially inseminated hens receiving saline drinking water.

Laying hens were selected at random and placed in individual cages in a commercial type layer shed. One hundred hens received town water and one hundred received town water supplemented with 2 g NaCl/L. Half the hens on each water treatment were inseminated every 7 days with mixed semen collected from six cockerels of a commercial table egg strain maintained on town water. The remaining hens were inseminated with semen from six cockerels receiving town water supplemented with 2 g NaCl/L. Eggs were collected and stored at 12 C over a 7-day period before eggs with defective shells were identified and removed. All remaining eggs were incubated and candled at 7 and 18 days of incubation to detect infertile eggs and embryonic deaths. Data from six consecutive hatches were analyzed. The incidence of eggs with defective shells doubled in hens receiving the saline drinking water. These hens had a significantly (twofold) higher incidence of embryonic deaths and a significantly lower (13%) hatchability of fertile eggs. For every 100 eggs laid the numbers of settable eggs and chicks hatched were significantly reduced in hens receiving the saline drinking water. The saline water reduced the numbers hatched by 20% for every 100 eggs laid. The water treatment given to the cockerels had little effect on reproductive performance.

Animals↗
PubMed1991

Use of ascorbic acid to prevent the decline in eggshell quality observed with saline drinking water.

Three experiments were carried out to determine the value of ascorbic acid in overcoming the poor eggshell quality problem associated with the use of saline drinking water. Laying hens were supplied with either town water or town water supplemented with NaCl, ascorbic acid, or a combination of NaCl and ascorbic acid. Supplementing the drinking water lf laying hens with NaCl (2 g/L) significantly increased the incidence of eggshell defects and significantly decreased eggshell quality. Simultaneous supplementation of the saline drinking water with ascorbic acid (1 g/L) prevented these detrimental effects. This response to ascorbic acid was dependent upon concentration. Ascorbic acid acted as a preventive rather than a remedial treatment: hens producing eggs with defective shells as a result of receiving saline drinking water failed to show any improvement in eggshell quality or any reduction in the incidence of eggshell defects when the saline water was supplemented with ascorbic acid.

Animals↗
PubMed1991

[Characterization of a human cell line from an anaplastic carcinoma of the thyroid gland].

A new cell line derived from a thyroid anaplastic carcinoma, CAL 62, has been established in culture. This line is constituted by highly tumorigenic cells. Their epithelial phenotype is stable in culture. Immunochemical staining for human thyroglobulin is negative. Cytogenetic analysis showed a gain of chromosome 20, the translocation i (14q), and breakpoints of centrometric chromatine. These results are similar to those previously reported by other investigators. CAL 62 radiosensibility has been studied. The survival curve of the in vitro irradiated cells has been adjusted with a linear-quadratic model. This cell line is thus showed to be radioresistant. Cell line CAL 62 constitutes an appropriate model for in vitro studies of thyroid anaplastic carcinoma.

Aged↗
PubMed1991

[Preparation of rotundine-chitosan gelled granules and their drug-release tests].

The paper described a delivery system prepared from granulation of a chitosan solution containing rotundine in a coagulating bath and examined the effects of the ratios of rotundine: chitosan, crosslinking agents and molecular weight of chitosan on the analgesic release rate. It was shown that the rotundine (56.7%)-chitosan (Mw:5.70 x 10(5) degree of deacetylation: 72.4%) gelled granules in an artificial gastroenteric juice (pH 1.0 and 7.2) have T50 of 40 and 180 min respectively, and the total release time sustained over 540 min.

Alkaloids↗