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Biomedical subjects

T Wang

Publications and source records attributed to T Wang.

At least 541 records · Page 30Linked to original sources
PubMed1996

Cardiorespiratory synchrony in turtles.

Many reptiles, particularly diving species, display characteristic cardiovascular changes associated with lung ventilation (cardiorespiratory synchrony). Previous studies on freshwater turtles show that heart rate and pulmonary blood flow rate (Qpul) increase two- to fourfold during ventilation compared with breath-holding, and some studies report concomitant decreases in systemic blood flow rate (Qsys). The primary aim of this study was to provide a detailed description of cardiorespiratory synchrony in free-diving and fully recovered turtles (Trachemys scripta). During breath-holds lasting longer than 5 min, Qpul averaged 15 ml min-1 kg-1 and increased more than threefold to a maximum value of 50 ml min-1 kg-1 during ventilation. Qsys also increased during ventilation compared with during breath-holds lasting longer than 5 min (from 44 to 73 ml min-1 kg-1 during ventilation). Neither Qpul nor Qsys was affected by the number of breaths in the ventilatory periods. Changes in Qpul and Qsys were accomplished entirely through a significant increase in heart rate during ventilation, while total stroke volume (systemic+pulmonary) remained constant. Irrespective of the ventilatory state, Qsys exceeded Qpul by 20-30 ml min-1 kg-1. Nevertheless, because Qpul increased relatively more than Qsys during ventilation, Qpul/Qsys increased from 0.29 during apnoea to 0.80 during lung ventilation. This study confirms cardiorespiratory synchrony in the turtle Trachemys scripta but, in contrast to earlier studies, a net right-to-left cardiac shunt prevailed regardless of ventilatory state.

Animals↗
PubMed1996

Is your organization's tax-exempt status at risk?

Not-for-profit healthcare organizations benefit enormously from their tax-exempt status. But in recent years, the IRS, Congress, and state and local governments have begun scrutinizing these organizations in an effort to find potential sources of new tax revenue. Since the survival of an organization may depend on retaining its tax-exempt status, healthcare executives must be able to justify their organizations' status by developing a written charity care policy, promoting the concept of community benefit, reviewing physician recruitment and retention policies to identifying and reporting unrelated business income, and submitting a concise Form 990 tax return to the Federal government.

Charities↗
PubMed1996

Construction of an insecticidal baculovirus expressing insect-specific neurotoxin AaIT.

Considering the factors which affect gene transcription, translation and the stability of mRNA, without changing the amino acid composition of the encoded polypeptide, AaIT gene encoding insect-specific neurotoxin was designed and synthesized according to bias in codon choice, overall G+C content and G+C content of bases at the third position in codons of polyhedrin genes of baculovirus and of plant genes as well. AaIT gene was fused behind a synthetic gp67 signal sequence and then recombined into the genome of Trichoplusia ni nuclear polyhedrosis virus (TnNPV) by transfer vector pSXIV VI+X3. The recombinant virus TnNPV-AaIT (occ+-gal-) was screened. The results of Southern blotting and SDS-PAGE demonstrated that AaIT gene had integrated into the genome of virus and expressed. Bioassays on the 3rd-instar Trichoplusia ni larvae showed that recombinant viruses TnNPV-AaIT could shorten the time of killing insect and improve the efficacy of killing agronomically important insects.

Animals↗
PubMed1996

Modulation of glutathione by a cysteine pro-drug enhances in vivo tumor response.

Glutathione (GSH) is known to play a role in cellular sensitivity to some chemotherapeutic agents and to radiation. Depletion of cellular glutathione increases toxicity of these drugs, and this approach is being explored in the clinic as a form of biochemical modulation using the drug buthionine sulfoximine. The fact that some drug-resistant cell lines have increased GSH levels, and that enhancing glutathione concentrations in animal tissues protects against a variety of xenobiotic agents, suggests a different potential approach to improve anticancer therapy. We previously showed a selective enhancement by the cysteine "pro-drug," L-2-oxothiazolidine-4-carboxylate (OTZ), of GSH concentration in some normal tissues of tumor-bearing rats, whereas there is a paradoxic GSH depletion in tumor. OTZ has been shown to protect animals from a variety of toxins, and in vitro studies showed a selective increase in GSH in normal cells that results in reduced sensitivity to some chemotherapy drugs. This report describes evidence that OTZ provides this effect in an in vivo rat mammary tumor model. We have examined the OTZ "activating" enzyme, 5-oxoprolinase, in these tumors and found it to be 4-fold lower than that of normal rat liver. This may explain at least the lack of increased GSH in tumor in response to OTZ. A limited number of human breast cancer samples show similar activity.

Animals↗
PubMed1996

Enhanced water intake after asymmetric hindbrain lesions.

Previous reports indicate rats with lesions of the lateral parabrachial nucleus (IPBN) or lesions of the area postrema (AP) and adjacent nucleus of the solitary tract (NTS) consume abnormally large amounts of water after treatment with SC isoproterenol (ISOP) or angiotensin II. In the present study, we found that IPBN bilateral lesions resulted in increased water intake after ISOP treatment as noted previously. We also found that rats with ibotenic acid lesions of the left IPBN and a knife cut on the right side of the AP drank an abnormally large amount of water after treatment with ISOP. Interestingly, rats with lesions of the right IPBN and a knife cut on the left side of the AP did not show the enhanced drinking behavior. Rats with AP and adjacent NTS lesions had an increased sodium appetite, but water intake after ISOP treatment was not enhanced. Bilateral IPBN lesions and asymmetric lesions of the AP and IPBN did not result in enhanced sodium appetite. These data suggest that a pathway from the AP/mNTS to the 1PBN is important in the regulation of fluid balance.

Animals↗
PubMed1996

Model development and analysis of tenidap-induced proteinuria in the rat.

Tenidap is a novel antirheumatic agent that causes a mild, reversible proteinuria in human clinical trials. In order to achieve a mechanistic understanding and safety perspective of the proteinuric effects of tenidap observed in clinical trials, female Sprague-Dawley rats were treated with up to 100 mg/kg/day of tenidap in the diet for 4 to 6 weeks followed by a 1- to 6-week reversal period. Pharmacokinetics and measurements of renal function and histology were assessed during the study. Sustained high plasma concentrations of tenidap [area under the plasma concentration curve (0-24 hr) of 941-1021 micrograms. hr/ml and peak plasma concentration of 61-67 micrograms/ml] increased urinary protein, albumin and phosphate excretion (2- to 8-fold) in rats. These renal effects were reversible within 9 days after removal of the drug. These effects preceded later occurring changes in renal morphology (papillary degeneration and necrosis). There was no evidence of glomerular damage, proximal tubule degeneration or necrosis or tubulointerstitial nephritis at the light microscopic level. Other indices of overall renal function (glomerular filtration rate, electrolyte and glucose excretion) were unaffected. Examination in situ of microperfused proximal tubules from treated rats revealed a 68% decrease in the rate of proximal tubule albumin absorption compared to controls (19 +/- 4 vs. 59 +/- 7 pg/min/mm, respectively). Fluid absorption rate and bicarbonate handling by the proximal tubule, along with blood bicarbonate concentrations, pH, PCO2 and PO2, were unaffected by treatment. It was concluded that tenidap caused a rapid, stable and reversible phosphaturia, microalbuminuria and proteinuria in the rat. The proteinuric effects were due to impaired proximal tubule albumin reabsorption that were not associated with other signs of impaired renal function or histological evidence of tubulointerstitial nephritis or proximal tubule/glomerular damage.

Albumins↗
PubMed1996

Endoscopic Intranasal dacryocystorhinostomy in forty-five patients.

OBJECTIVE: To observe the results of endoscopic intranasal dacryocystorhinostomy. METHODS: Forty-five patients (forty-eight eyes) suffering from chronic dacryocystitis received endoscopic intranasal dacryocystorhinostomy after November 1991, and were followed up for 3 to 36 months. RESULTS: Thirty-nine eyes were cured (81.2%). It is significantly effective (8.3%) in 4 eyes, and effective in 2 eyes (4.2%). The total effective rate was 93.7%. CONCLUSIONS: The intranasal approach is simple causing little bleeding and no facial scar. With the self-made dacryocyst-illuminator (diameter = 0.8 mm), and by transilluminating the lacrimal sac with fiberoptic intraocular endoilluminator bundle, the sac can be located endonasally, thus facilitating the approach.

Adult↗
PubMed1996

[Observation on activity of carbonic anhydrase in the vestibule of guinea pigs].

The localization of carbonic anhydrase (CA) activity in the inner ear vestibule of guinea pigs were studied by histochemistry and cytochemistry. We found that numerous enzymatic reaction products were localized in the sterecocilia, cuticles of hair cells, no reaction product was seen in their cell bodies; revealed reaction products in the cell membrane, microvilli, lateral infolding and basolateral infolding of the supporting cell, dark cell, transitional cell and wall cell. It is suggeated that the CA is a membrane-associated CA and the membrane-associated CA plays an important role in the homeistasis of the vestibule and otolithic metabolism.

Animals↗
PubMed1996

[Use of an anorectal driving device in the sphincter-saving operation for low rectal carcinoma].

UNLABELLED: The anastomosis with tubular anastomotic instrument for the surgical resection of the low rectal carcinoma with preserved anus is difficult to perform because of the deep location of the tumor and retraction of the paraproctium to the pelvic floor. From 1986 a self-made anorectal driving device was applied to facilitate anastomosis with the tubular anastomotic instrument. Ninety-six cases of low rectal carcinoma were so treated in 1986-1990. Eighty-five cases in 1980-1985 treated by tubular anastomosis without the use of the driving device served as the control. The success rate of anastomosis increased from 45.9% to 77.1% (P < 0.01), incidence of anastomotic fistula decreased from 11.6% to 3.1% (P < 0.01), the average operation time was reduced from 211 to 183 minutes (P < 0.01). CONCLUSION: The pelvic and anoretal tissue can be pushed upwards by this device, which facillitates complete dissection of the tumor and anastamosis by tubular anastomotic instrument.

Anastomosis, Surgical↗
PubMed1996

[Histochemical and electron microscopical study on mast cells in the stroma of thyroid tumours].

To understand the number and morphology of the mast cells of throid tumours stroma, the mast cells (MCs) of 62 cases of thyroid tumour stroma were studied histochemically and electron microscopically. The number of MCs was increased significantly in thyroid tumour as compared with that in normal tissues. The number of MCs between thyroid cancer and thyroid adenoma was of no difference. When stained with Alcian Blue-Safranin, MCs in the stroma of normal thyroid were blue whereas in the stroma of thyroid tumour both blue and red mast cells could be found. The ultrastructure of the granule of the MCs was homogeneous electron-dense, which was the characteristic feature of TMCs. Degranulation of MCs adjacent to tumour cells could be seen. The significance of MCs in the stroma of thyroid tumour was discussed.

Adenocarcinoma, Follicular↗
PubMed1996

[An experimental study on the effects of total parenteral nutrition on gut immune barrier function].

In this study, SPF rat models were used. The purpose of the study was to observe the impairment of gut barrier function subsequent to long-term TPN, and evaluate the effect of TPN enriched by alanyl-glutamine (Ala-Gln) on the gut. After 7 day standard TPN, there was a significant decrease of CD3+, CD4+, CD8+ and IgA-containing plasma cells in lamina propria. The percentage of intestinal bacteria coated by S-IgA declined, and bacterial adherence to intestinal epithelial cells increased with an increased incidence of bacterial translocation to mesenteric lymph nodes. All these adverse effects could be attenuated by addition of Ala-Gln to TPN solutions or oral glutamine (Gln) or Ala-Gln administration. The results of the study suggested that long-term standard TPN impaired the immune gut barrier function and therefor facilitated enterogenic infection, and addition of Gln or Ala-Gln significantly benifited gut barrier protection and infection prevention, which might be important to clinical practice.

Animals↗
PubMed1996

[Chemical constituents of Notopterygium forbesii Boiss].

Nine compounds were isolated from the under-ground part of Notopterygium forbesii. On the basis of physicochemical properties and spectroscopic analysis, they were identified as phellopterin, isoimperattorin, notopterol, nodakenitin, nodakenin, 6-O-trans-feruoylnodakenin, p-hydroxyphenethyl anisate, pregnenolone and beta-sitosteroi, of which phellopterin was obtained from the plant of Notopterygium genus for the first time.

Drugs, Chinese Herbal↗
PubMed1996

Effects of Chinese medicine zhenxianling in 239 cases of epilepsy.

Oral and external (on the umbilicus) application of Chinese medicine Zhenxianling (an anti-epileptic agent) to a series of 239 cases of epilepsy of various types obtained a total effective rate of 95.4%. Moreover, an effective rate of 97.2% was achieved in grand mal epilepsy. All cases in this series were treated for 6 months to 2 years, and followed up for 6 months to 3 years. This agent is recommendable for it being prepared exclusively with Chinese medicine, convenient in use without side-effects.

Adult↗
PubMed1996

[Superoxide dismutase and malonyl dialdehyde in human pulp tissue].

A total of 21 pulps were collected from 12 inflamed and 9 normal cases. SOD activity and MDA content were identified in the normal and inflamed pulpal tissues. In the inflamed pulpal tissues, SOD activity and MDA content were significantly increased than those in the normal tissues. The results demonstrated that the inflammation of pulpal tissues resulted in the increasing of the reactivity of superoxide radical and lipid peroxide (LPO). The results also indicated that human dental pulp possessed an endogenous defense mechanism to protect the tissue components from the toxic effects of the reactive oxygen intermediates.

Adult↗
PubMed1996

Glutamate-induced swelling of cultured astrocytes is mediated by metabotropic glutamate receptor.

The effects of glutamate and its agonists and antagonists on the swelling of cultured astrocytes were studied. Swelling of astrocytes was measured by [3H]-O-methyl-D-glucose uptake. Glutamate at 0.5, 1 and 10 mmol/L and trans-1-aminocyclopentane-1, 3-dicarboxylic acid (trans-ACPD), a metabotropic glutamate receptor (mGluR) agonist, at 1 mmol/L caused a significant increase in astrocytic volume, whereas alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA) was not effective. L-2-amino-3-phosphonopropionic acid (L-AP3), an antagonist of mGluR, blocked the astrocytic swelling induced by trans-ACPD or glutamate. In Ca(2+)-free condition, glutamate was no longer effective. Swelling of astrocytes induced by glutamate was not blocked by CdCl2 at 20 mumol/L, but significantly reduced by CdCl2 at 300 mumol/L and dantrolene at 30 mumol/L. These findings indicate that mGluR activation results in astrocytic swelling and both extracellular calcium and internal calcium stores play important roles in the genesis of astrocytic swelling induced by glutamate.

Animals↗
PubMed1995

In vivo selective modulation of tissue glutathione in a rat mammary carcinoma model.

Glutathione (GSH) is known to play a role in cellular sensitivity to some chemotherapeutic agents and to radiation. Depletion of cellular GSH has been demonstrated to result in enhanced toxicity of these drugs, and this approach is being explored in the clinic as a form of biochemical modulation, using the drug buthionine sulfoximine (BSO). The fact that some drug-resistant cell lines have increased glutathione levels, and that enhancing GSH concentrations in animal tissues protects against a variety of xenobiotic agents, suggest a different potential approach to improving anti-cancer therapy. We have examined the efficacy of the cysteine "pro-drug" L-2-oxothiazolidine-4-carboxylate (OTZ) at enhancing normal tissue versus tumor GSH. Animals were treated with OTZ or BSO, and the concentrations of GSH in normal tissues and tumor were measured. We found that the presence of the tumor itself decreased bone marrow GSH, but that OTZ significantly increased it in this setting. Interestingly, OTZ administration significantly depleted tumor GSH levels to the same level as did BSO. OTZ could offer a selective biochemical modulation of GSH.

Animals↗