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Biomedical subjects

H Shen

Publications and source records attributed to H Shen.

At least 145 records · Page 8Linked to original sources
PubMed2000

[Growth and metabolism of hybridoma cells in semicontinuous perfusion cultures].

The growth and metabolism of WuT3 hybridoma cells were studied in semicontinuous perfusion cultures. The growth of cells, utilization of glucose, production of lactate, ammonia and monoclonal antibody were investigated. As the perfusion rate increased from 1.0/d to 2.0/d, the lactate yield coefficient from glucose Ylac/glu decreased 18%, the ammonia yield coefficient from glutamine Yamm/gln decreased 40%, the alanine yield coefficient from glutamine Yala/gln increased 58%, the glycine yield coefficient remained almost constant. This indicate that cells would regulated their metabolic flux at higher cell density, and glutamate produced in quantity and pyruvate would turn into alanine rather than glycine by transamination. As a result, potentially toxic effects were reduced because less ammonia and lactate were produced.

Amino Acids↗
PubMed2000

[Detection of DNA strand breakage in human spermatozoa by use of single-cell gel electropheresis].

OBJECTIVE: To establish the single-cell gel electropherosis (SCGE) protocol for detection of DNA strand breakage in human spermatozoa. METHODS: The slides on which sperm cells and agarose were layered were immersed in a cold lysing solution of pH10 to lyse the sperm cells. Sperm nuclei were then pretreated with 10 mmol/L of DTT for 1 h, 10 microg/ml of RNase A for 4 h and 200 microg/ml of proteinase K for 15 h. Lastly, electrophoresis was performed in electrophoresis running buffer(pH10) at 12V (0.46V/cm) and 100 mA for 1 h. Sperm nuclei were stained with 15 microg/ml of EtBr for 5 min. The percentage of comet cells was counted. The in vitro hydrogen peroxide-induced DNA damage in human spermatozoa was measured with SCGE established by this laboratory. RESULTS: The comet sperm cells in human spermatozoa ranged from 2% to 38%. There was a significant variance on the percentage of comet cells between different subjects. Hydrogen peroxide increased the percentage of comet sperm in a dose- and time-dependent manner. CONCLUSION: SCGE may be used to detect DNA strand breakage in human spermatozoa. Hydrogen peroxide-induced DNA damage in human sperm cells was detected successfully using SCGE protocol established by this laboratory.

DNA Damage↗
PubMed2000

[Growth and metabolism of hybridoma cells cultured in flask and spinner bottles].

The growth and metabolism of WuT3 hybridoma cells were very different when cells were cultured in flask and spinner bottles. In the flask bottles, a longer culture duration and the higher cell density were met, whereas in the spinner bottles the more vigorous cell metabolism took place, resulting in that either the specific consumption rates of glucose and amino acids or the specific production rates of lactate, ammonia and alanine were higher.

Amino Acids↗
PubMed2000

Regular form factor. A new concept and calculating method for quantitative form description.

OBJECTIVE: To quantitatively describe the shape of two-dimensional particles based on combined consideration of area (A), circumference (C), and major and minor diameter (d1 and d2, respectively). STUDY DESIGN: A regular form factor (RFF), a new concept and calculating method for form description, was defined as the extent to which a structure differs from an ellipse or circle of which the major and minor diameters, respectively, are equal to the described structure. Based on the definition of RFF, formulae were deduced in accordance with mathematical principles. RESULTS: The deduced formulae were as follows: RFF = A [1.5(a + b) - square root of (a b)]/(a b C) and RFF = A [3 (d1 + d2) - 2 square root of (d1 d2)]/(d1 d2 C). In the formulae, a = d1/2, and b = d2/2. RFF = 1 for ellipses and circles, and < 1 for irregular particles. The more similar to an ellipse or circle, the closer to 1 is RFF. The more irregular the structures are, the smaller the values of RFF. An error analysis was also made, and a rectified formula for RFF was deduced. An example is given to show how to calculate RFF. A practical test of RFF was made in colorectal adenoma and adenocarcinoma in human material, and the results show that RFF of glands of colorectal adenoma and adenocarcinoma have significant differences between normal, adenoma and adenocarcinoma. CONCLUSION: RFF was compared with the parameter Form AR, and the results showed that RFF is more sensitive in describing the irregularity of a structure than Form AR. RFF is of practical significance for describing structures in human material.

Adenocarcinoma↗
PubMed2000

[Changes of plasma renin activity and angiotensin II levels in women with polycystic ovary syndrome].

OBJECTIVE: To investigate changes of plasma renin activity(PRA) and plasma angiotensin II (PANG II) in women with polycystic ovary syndrome(PCOS). METHODS: We chose thirty PCOS women as trial group and thirty normal menstrual women as control. PRA and PANG II levels during follicularphase(FP) of the two groups were measured by radioimmunoassay. RESULTS: PRA and PANG II increased in women with PCOS as compared with the normal FP. The increment of PRA and PANG II in PCOS women of high testosterone levels was correlated with serum luteinizing hormone/follicle-stimulating hormone and testosterone concentration. CONCLUSION: The elevated PRA and PANG II suggest an enhanced functional activity of ovarian renin angiotensin system in PCOS, and which may play a role in the pathologenesis of PCOS.

Adult↗
PubMed2000

[Evaluation on soil anti-erodibility of soil and water conservation forest].

Indexes including organic matter content, water stable aggregate content, mean weight diameter of water stable aggregate, aggregate degree and disperse coefficient were selected to evaluate soil anti-erodibility of soil and water conservation forests component of different tree species at different ages. The results showed that soil and water conservation forest played an important role in improving soil anti-erodibility, especially to the topsoil. Compared with that of Chinese pine pure forests, Chinese pine-broadleaved mixed forests had higher soil organic matter content, and water stable aggregate content increased by 1.71%-38.53%, and soil anti-erodibility was also increased with increasing stand age.

China↗
PubMed2000

Comparison of computer-photoscreening with non-cycloplegic retinoscopy for amblyopiogenic risk factors in children.

OBJECTIVE: To determine the sensitivity and specificity of using a computer-photoscreener and non-cycloplegic retinoscopy in the detection of amblyopiogenic factors in nine to fifty months old infants and children. METHODS: Three hundred children, nine to fifty months old, were screened with the computer-photoscreener and non-cycloplegic retinoscopy. With a blinded standardized clinical assessment as the standard, an overall comparison of the sensitivity of and specificity results obtained with the two techniques was made. Photoscreen images on the computer monitor screen were reviewed and analyzed immediately by two independent observers for indicators of amblyopiogenic risk factors. Simultaneously, the results were compared to the findings of a full ophthalmologic examination. RESULTS: The computer-photoscreener revealed a sensitivity of 94.6% and specificity of 90.1%, and the non-cycloplegic retinocopy revealed a sensitivity of 85.7% and specificity of 81.0% for the detection of amblyopiogenic risk factors, including hyperopia (+2.75 D or more), myopia (-1.50 D or more), astigmatism (1.75 D or more), anisometropia (2.00 D or more), ocular misalignment (5 degrees or more), and media opacity (1.5 mm or more). CONCLUSIONS: The computer-photoscreener offers an opportunity to identify problems that limit vision, and could provide a feasible and sufficiently reliable screening technique in infants and preschool children to be screened successfully for amblyopiogenic risk factors.

Amblyopia↗
PubMed2000

[Endometrial nuclear progesterone receptors in infertile women].

OBJECTIVE: To investigate the endometrial nuclear progesterone receptors (PgR) as well as its relationship with retarded endometrial development (RED) in infertile women. METHODS: The progesterone profile, endometrial nuclear progesterone receptors (PgR) and endometrial biopsies were studied by using (125)I radioimmunoassay and immunohistochemical technique in 53 infertile women during median luteal phase. When the endometrial dating lagged 2 days behind the dating as determined by luteinizing hormone (LH) surge, diagnosis of luteal phase defect (LPD) was made. According to progesterone profile and endometrial morphology, the patients were divided into three groups: normal, luteal phase defect (LPD) and pseudocorpus luteum insufficiency (PLI). RESULTS: During median luteal phase, RED were found in all of 24 cases with LPD and PLI, but PgR contents were different in them. Mean progesterone profile of 9 cases of PLI cycles was normal (60.2 nmol/L) but the endometrial nuclear PgR appeared to be prominently lower than in normal cycles during the median luteal phase (P < 0.01). Average progesterone level of 15 cases of LPD cycles were significantly lower (29.9 nmol/L) but endometrial nuclear PgR were similar to normal group (P > 0.05). CONCLUSION: Retarded endometrial development may have different causes. Measurement of endometrial nuclear PgR is of assistance in differential diagnosis.

Adult↗
PubMed2000

[The effect of burn sera on the calcium homeostasis in isolated rat myocardial cells].

OBJECTIVE: To study the effect of burn sera on the calcium homeostasis in isolated rat myocardial cells. METHODS: The burn sera were obtained from the Sprague -- Dawley (SD) rats inflicted by 30% TBSA III degree burn at 2, 4 and 6 postburn hours with the harvesting of burn sera at different postburn times, named as 2 hBS, 4hBS and 6 hBS, respectively. Myocardial cells were isolated by enzyme digestion with retrograde perfusion apparatus. [Ca(2+)]i was detected with the fluorescent dye Fura -- 2 and L -- type calcium (ICa -- L) currents were recorded in the whole -- cell patch -- clamp model. RESULTS: Myocardial cellular [Ca(2+)]i became much higher in concent after being in cubated with sera, especially with 6hBS, than that in normal myocardial cells (P < 0.01). But the effect of 6hBS could be significantly inhibited by verapamil (30 nmol/L), the calcium channel antagonist and procaine (2 mmol/L), the inhibitor of rynodine receptor (P < 0.01) by 47.7% and 67.6%, respectively. Ca -- L was evidently increased by the stimulation of 2 hBS and 6 hBS, by 50 -- 80% and 1.5 -- 2.5 folds, respectively. It was indicated by I -- V curves that every ICa caused by depolarizaton and clamp voltage was increased by burn sera, which further made the maximal activating voltage ahead of time. All the burn sera effects on calcium current could be removed by extracellular lavage. CONCLUSION: The myocardial [Ca(2+)]i and ICa -- L could increase significantly when affected by burn sera. The alteration in calcium homeostasis might be a cellular mechanism of myocardial injury.

Animals↗
PubMed2000

[Alterations of anabolism in hepatic cells of burned rats measured by (13)C NMR spectroscopy].

OBJECTIVE: To introduce a safe and specific approach of (13)C NMR spectroscopy and investigate the alterations in hepatic anabolism functions including pyruvate recycling, gluconeogenesis and anaplerosis in severely burned rats. METHODS: Adult Spreque -- Dawley (SD) rats were catheterized arteriovenously via left carotid and right external jugular vein under inhalation anesthesia and were randomly divided into burn group (B) and sham burn group (S). Fluid resuscitation started 20 min postburn. Sodium [1, 2, 3 -- (13)C] propionate (SP) was intravenously administered as a tracer at 72 postburn hour (PBH). (13)C NMR spectroscopy of extracted plasma and liver, arterial blood pressure, heart rate and plasma glucose and sodium levels were measured. Metabolic parameters were calculated using a mathematical model of input -- output matrix to feed the tricarboxylic acid cycle. RESULTS: When compared to those in C group, burned rats exhibited a lower arterial blood pressure, but normal blood glucose at 72 PBH. Intravenous SP infusion did not alter MAP, heart rate and plasma sodium. The form of blood sugar labeled by (13)C isotopomer was in excellent agreement with that from liver. After continuous infusion of SP for 45 mins, SP could reach metabolic steady status. The hepatic cellular gluconeogenesis, anaplerosis and the carbon flow rate in pyruvate recycling significantly increased in B group when comparing to those in C group. But the carbon flow rate in Kreb's cycle decreased relatively, and hepatic pools of alanine, glutamic acid and glutamine were enlarged obviously in burned rats relative to sham burn group. CONCLUSION: These data suggested that intravenous infusion of SP would not alter MAP, heart rate and blood sodium. Forty -- five mins after the intravenous infusion, the tracer could reach metabolic steady status. The form of blood sugar labeled by (13)C could represent that of hepatic sugar. Seventy -- two hours after major burns, there were increased hepatic anaplerosis, gluconeogenesis and pyruvate recycling and a correspondent increased utilization ratio of blood sugar by peripheral tissue.

Animals↗
PubMed2000

[The study on effects of human fetal liver cells on immunity of BALB/c mice].

This study sought to better understand the effects of human fetal liver cells(FLC) on immunity. FLC were injected into BALB/c mice intraperitoneally. The design included four groups: negative control and three dose (125 x 10(5), 25 x 10(5), 5 x 10(5) FLC/day) groups. The results showed that FLC increased the thymus visceral coefficient, numbers of T-lymphocytes(TLC) and lymphocytes(LC) in blood, total number of spleen cells, the number of plaque forming cells(PFC) of spleen, the rate(%) of transformation and stimulus index of TLC of spleen, and the function of macrophages. FLC also effected the function of natural killer cells(NK cells) of BALB/c mice. The findings suggest that human FLC can strengthen the nonspecific immunity, humoral immunity and cellular immunity in mice. In this study, however, no effect of FLC on spleen visceral coefficient was noticed, and no sign of delayed type allergy was observed.

Animals↗
PubMed2000

[Effect of vasostomy on expression of Bcl-2 and Bax gene in rat spermatogenic cells].

The objective of this study was to explore the change of Bcl-2 and Bax gene expression in rat spermatogneic cells after vasostomy. A rat model with vasoligation and vasostomy was set up and then used for detecting the protein expression of Bcl-2 and Bax gene at 4, 8, 12, 16 weeks after vasostomy by means of immunohistochemistry. Sixty rats were randomly distributed into three groups named vasoligation group (VG), vasostomy group(VOG) and sham-operation group(SOG) respectively. The results showed that the Bcl-2 protein expression in VOG group increased gradually and came to be significantly higher than that in VG group 8 weeks after vasostomy, and it's level was the same as that in SOG group at the 12th week. The bax protein expressions in VG and VOG groups were significantly higher than that in SOG group, but there was no difference between VOG and VG groups. In conclusion, the change of Bcl-2 protein expression observed in this study is indicative of the anti-apoptosis function of Bcl-2 gene in both the status of being vasoligated and vasostomized, whereas the consistent Bax protein expression before and often the repatency of the vas suggests further researches into its effect on apoptosis of spermatogenic cells.

Animals↗
PubMed2000

[Determination of trace Cr in medical material progesterone by flame atomic absorption spectrophotometry].

This paper report the development of the determination of trace metal Cr in medical material progesterone by flame atomic absorption spectrophotometry. After the organic compounds are eliminated by HNO3-H2O4 to decomposite completely, the sample is determinated by FAAS. The method is convenient and the results show good precision and accuracy. The relative standard deviation was 3.0% and the rate of recovery was 98.8%.

Chromium↗
PubMed1999

Medial prefrontal cortical output neurons to the ventral tegmental area (VTA) and their responses to burst-patterned stimulation of the VTA: neuroanatomical and in vivo electrophysiological analyses.

During a delayed period in a delayed-response task, prefrontal cortical neurons show a change in neuronal firing rate that is dependent on a functional mesocortical dopamine input. This change in firing rate has been attributed to be part of the cellular processes underlying working memory. However, it is unclear what neural mechanisms activate mesocortical dopamine neurons to provide an optimal level of dopamine to modulate the firing of the medial prefrontal cortical (mPFC) neurons. This study examined the possibility of whether mPFC neurons that project to the ventral tegmental area (VTA) might activate the ascending mesocortical dopamine neurons. To determine the locations of the mPFC-->VTA neurons, cholera toxin subunit B was microinjected into the VTA. Retrogradely labeled mPFC neurons mainly reside in the deep lamina V and VI. In vivo single unit recording in urethane-anesthetized rats were also used to determine the responses of some of these neurons to burst-patterned stimulation of the VTA. Single-pulse stimulation (1 Hz) of the VTA antidromically activated burst firing mPFC-->VTA neurons. In response to burst-patterned stimulation of the VTA, which mimicked burst firing of VTA dopamine neurons (4-10 pulses at 10-15 Hz cycled at 0.5-3 Hz), the temporal structure of spontaneous burst firing patterns of these neurons but not their mean firing rate were changed. However, the mean firing rate of the non-VTA projecting neurons (i.e., no antidromic response to VTA stimulations) was either increased or decreased by similar burst-patterned stimulation of the VTA. These data suggest that burst-patterned stimulation of the ascending VTA-->mPFC or putative mesocortical dopamine neurons might have released dopamine and/or other neuromodulators to modulate the temporal code, rather than the rate code, of mPFC-->VTA neurons. Medial PFC neurons that project elsewhere (e.g., nucleus accumbens or mediodorsal thalamus) may mediate the sustained firing rate changes during, e.g., short-term working memory.

Animals↗
PubMed1999

Ultrastructural analysis of polysialylated neural cell adhesion molecule in the suprachiasmatic nuclei of the adult mouse.

The suprachiasmatic nuclei (SCN) of the anterior hypothalamus are recognized as the principal circadian clock in mammals. The adult SCN express a high level of polysialylated neural cell adhesion molecule (PSA-NCAM), a cell surface sialoglycoprotein capable of modulating cell-cell interactions. In the present study, the expression of PSA-NCAM in the mouse SCN was studied at the ultrastructural level by immunolabeling using monoclonal antibodies against the polysialic acid (PSA) moiety of PSA-NCAM. We showed that neuronal somal expression of PSA-NCAM was distributed heterogeneously in the SCN, with extensive staining of somas in the central region of the SCN, and minimal somal staining in the ventral portion of the nuclei. In contrast, immunoreactive neuropil, including unmyelinated fine axon fascicles was distributed throughout the SCN. The PSA-NCAM was also detected adjacent to synaptic junctions by both immunoperoxidase and immunogold techniques. For astrocytes, immunostaining of somas and larger processes was sparse, but staining was profuse along fine processes. Immunostained fine astrocytic processes were frequently observed between apposing neuronal somas, and in close association with synaptic junctions and small blood vessels. These findings, together with the demonstrated role of PSA-NCAM in modulating cell-cell interactions in other brain regions support a role for PSA-NCAM in regulating cell-cell interactions in the SCN.

Animals↗
PubMed1999

A comparison of T cell memory against the same antigen induced by virus versus intracellular bacteria.

Cytotoxic T cell (CTL) memory was analyzed after infection with lymphocytic choriomeningitis virus (LCMV) and recombinant Listeria monocytogenes (rLM) expressing the complete nucleoprotein of LCMV (rLM-NP(actA)) or only the immunodominant epitope of H-2(d) mice (rLM-NP(118-126)). Immunization with LCMV and rLM induced a long-lived increased CTL precursor (CTLp) frequency specific for the viral (NP(118-126)) and for the bacterial (LLO(91-99)) epitope, respectively. However, after infection with rLM memory, CTLs were less protective against an intravenous LCMV challenge infection than a comparable number of LCMV-induced memory T cells. LCMV, but not recombinant Listeria-induced memory T cells were able to protect against lethal choriomeningitis by LCMV or a subsequent peripheral infection with recombinant vaccinia virus expressing LCMV-NP. The protective memory after viral and after rLM immunization was paralleled by evidence of LCMV but not rLM antigen persistence on day 15 and 30 after vaccination. These results document a striking difference in protective T cell memory between viral and bacterial vaccines and indicate that rapid T cell-dependent immune protection correlates with antigen persistence.

Animals↗
PubMed1999

Effects of the acute and chronic restraint stresses on the central histaminergic neuron system of Fischer rat.

The effects of acute and chronic restraint stresses on the brain histamine level and histamine N-methyltransferase activity in Fischer rat brain were studied. The acute restraint stress increased the histamine levels in the diencephalon and nucleus accumbens, and increased the histamine N-methyltransferase activities in the nucleus accumbens and striatum. The chronic restraint stress also increased histamine N-methyltransferase activities in the nucleus accumbens and striatum. These results indicate that the acute and chronic restraint stresses increase the brain histamine turnover, which may partly relate to the vulnerability for stress-induced anxiety and depression.

Acute Disease↗