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Biomedical subjects

Y Wan

Publications and source records attributed to Y Wan.

140 records · Page 8Linked to original sources
PubMed1994

Remote tissue injury primes hepatocytes for nitric oxide synthesis.

Following trauma and tissue injury, patients frequently suffer infections and septic complications. Tissue injury is associated with the induction of the hepatic acute-phase response, but how this phenotypic expression by hepatocytes influences their subsequent response to endotoxin (lipopolysaccharide, LPS) or inflammatory cytokines is unknown. We have shown that both rat and human hepatocytes maximally express the enzyme-inducible nitric oxide synthase (iNOS) in response to a combination of LPS and the cytokines tumor necrosis factor (TNF), interferon-gamma (IFN-gamma), and interleukin-1. Furthermore, we have shown that the in vivo induction of the acute-phase response following tissue injury (hind limb turpentine injection) is not associated with hepatocyte iNOS expression. In this study, we show that the phenotypic change associated with the acute-phase response following tissue injury primes the hepatocyte to subsequently express iNOS in vitro in response to LPS alone as well as TNF and IFN-gamma. This expression of iNOS can be seen as early as 3 hr following the initial injury and lasts up to 24 hr. Early postinjury changes result in maximal expression following stimulation with TNF or IFN-gamma. Later (24 hr post-injury) changes reveal LPS to be the most potent inducer with as little as 0.01 microgram/ml LPS being required for iNOS mRNA expression. The in vivo correlate of tissue injury (turpentine injection) followed by sepsis (intraperitoneal LPS injection) resulted in a three- to fourfold rise in plasma levels of the stable end-products of nitric oxide production, nitrite, and nitrate (NO2- + NO3-), over levels seen in cases of sepsis alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Changes of angiotensin II contents in rat plasma, brain, cardiovascular system and adrenal during stress].

The changes of content of angiotensin II (A II) in plasma, anterior hypothalamus, medulla oblongata, myocardium, vasculature and adrenals during acute and chronic stress were studied in rats. Compulsive cold-water swimming and trauma by limb-breaking were used to set acute stress models while cold environment of 4-8 degrees C was used to set chronic stress model. The results showed that: (1) The A II levels in plasma were significantly increased in all three stress- model groups, reaching to 900%, 390% and 134% of the control in the swimming group, the limb-broken group and the cold environment group, respectively. It's clear that the level of angiotension II in the acute stress groups were much higher than those in the chronic stress group. (2) The A II levels of the rat brain, myocardium and blood vessel were also increased in the stress animals except the limb-broken group. Furthermore, the contents of angiotensin II of the chronic stress animals were significantly higher than those of the acute stress animals in the brain, myocardium and blood vessels, but not in the adrenals. (3) The adrenal A II content was significantly higher than that of the control in all stressed animals. (4) The plasma corticosterone was also significantly increased over the control level in both the acute and chronic stress groups. These results suggest that circulating angiotensin II and tissue angiotensin II may play a role during the development of acute and chronic stress, respectively.

Adrenal Glands↗
PubMed1993

[Effect of estradiol on the course of ovalbumin sensitization in guinea pigs].

The latent period of ovalbumin (Ova)-induced asthma in Ova-sensitized guinea pigs was shorter in the ovariectomized animals with sc estradiol (E2) 400 or 50 micrograms.d-1 x 14 d and in animals with intact ovary (84 +/- 35, 82 +/- 33, and 100 +/- 32 s, respectively) than in the ovariectomized animals (140 +/- 29 s) (P < 0.05). The histamine (His) content of the lungs and His released from lungs under Ova challenge in vitro increased in the group of ovariectomy with sc E2 50 micrograms.d-1 x 14 d as compared with those without sc E2 (56 +/- 9 and 47 +/- 11 ng/g wet weight vs 44 +/- 10 and 36 +/- 11 ng/g wet weight) (P < 0.05). However, the pD2 values of the contraction of isolated tracheal strips induced by His and those of the relaxation by isoproterenol (Iso) were not affected. These findings suggest that the strengthened effect of E2 on the sensitization may be related to the content and the release of lung His in guinea pigs.

Animals↗
PubMed1989

[A follow-up study on rapid cycling affective disorders].

Of 27 cases, 18 manic-depressive patients who simultaneously fitted dunners' seminal definition about rapid cycling affective disorders (RCAD) completed clinical follow-up for 1.5-4.5 years after discharge between Jan, 1983 and Jun, 1986. The results showed that 8 cases relapsed into manic-depressive episodes, the other 10 cases had no relapsed. Only one case belonged to relapsing of RCAD during the follow-up duration. The cases with relapsing of depression responded to lithium or to stopping use of antidepressants, but the cases with relapsing of manic episodes responded to carbamazepine. The differences in therapeutic response in such cases suggested that RCAD probably presented biological heterogenecity.

Adolescent↗
PubMed1989

[Effects of human chorionic gonadotrophin and progesterone on small intestinal migrating myoelectric complex in rats].

The effects of human chorionic gonadotrophin (HCG) and progesterone (P) on migrating myoelectric complex (MMC) of the small intestine in ovariectomized rats were investigated by implanted monopolar-electrode in the intestinal wall of the duodenum, jejunum and ileum. The results showed (1) after i.v. administration of HCG the periodicity of the duodenal and upper jejunal MMC was interrupted by irregularly prolonged phases II occurring intermittently; (2) after i.m. administration of P the duration of phases I and II of the duodenal MMC was significantly prolonged, but the periodicity was not affected; (3) the effect of P plus HCG on MMC was similar to that of HCG alone, but the combined effect was spread over the whole small intestine. These results suggest that HCG can induce remarkable changes of the small intestinal MMC, which are similar to those observed in pregnant rats. In the presence of P, the effect of HCG is enhanced markedly.

Animals↗
PubMedDate not supplied

Purification and identification of ABA-binding proteins and antibody preparation.

Maize root membranes were extracted and the solubilized proteins were affinity-purified using an ABA-BSA-Sepharose 4B matrix. The retained proteins were eluted with 4M urea or 10(-4)M ABA. ABA could elute the binding proteins but other phytohormones, such as IAA or GA3, could not. ABA binding activity was detected in ABA- and urea-elute fractions using competitive ELISA block tests and [3H]ABA binding assays. Scatchard analysis showed an apparent K(d) of 4.8 nM for the ABA binding activity of the protein. When ABA or urea eluate was loaded on a concanavalin-A-Sepharose column, the fraction eluted with 0.2 M methyl alpha-mannopyranoside still showed ABA binding activity, suggesting that ABA binding proteins are glycoproteins. Polyclonal antibodies against ABA binding proteins were raised using as immunogen ABA or urea eluate from the ABA-BSA-Sepharose column. The resulting antibodies not only recognized 56 kDa binding proteins but also blocked the binding of ABA to an ABA-specific antibody, indicating properties similar to anti-idiotypic antibodies. The purified antibodies will be suitable to purify and characterize putative ABA receptors.

Abscisic Acid↗
PubMedDate not supplied

Angiotensin II--an important stress hormone.

Angiotensin II (Ang II) is an important stress hormone. Circulating and tissue Ang II are significantly increased in both acutely and chronically stressed animals. In humans, the plasma Ang II content increases markedly after sprinting, as does cortisol. The present paper reviews recent studies with special reference to the correlation between the renin-angiotensin system (RAS) and the hypothalamus-pituitary-adrenal cortex system and sympathetic-adrenal medulla system during stress. We would like to suggest that in the stress response, Ang II is not only a stress hormone to various peripheral organs, but is also a notable factor in initiating the systemic stress response from central to peripheral tissues. The RAS is therefore a stress hormone response system similar to the hypothalamus-pituitary-adrenal cortex system and the sympathetic-adrenal medulla system.

Angiotensin II↗
PubMedDate not supplied

Changes in circulating and tissue angiotensin II during acute and chronic stress.

Changes of angiotensin II and cAMP in plasma, brain tissue, adrenal gland and cardiovascular tissue during the acute and chronic stress were studied in rats. The acute stress group was subjected to compulsive cold water swimming for 20 min, while the chronic stress group was exposed to an ambient temperature of 4-8 degrees C for 5 days. The results indicated that plasma angiotensin II levels were significantly increased in both stress groups, reaching up to 900% and 134% of the control in the acute and chronic groups, respectively. Angiotensin II contents in the anterior hypothalamus, medulla oblongata, myocardium, vasculature and adrenals were also elevated in both groups. With the exception of the adrenals, the contents of tissue angiotensin II in the chronic stress animals were significantly higher than those of the acute stress animals. In contrast, cAMP levels in plasma and tissue (hypothalamus and adrenals) and corticosterone levels in plasma in the acute stress group were all higher than those in the chronic stress animals, although the levels of the latter group were also increased compared with the control group. These results suggest that circulating and tissue angiotensin II may play an important role in the acute and chronic stress responses and that angiotensin II should be classified as a stress hormone.

Adrenal Glands↗