Search PubMed⌕ Search

Biomedical subjects

Huan Wang

Publications and source records attributed to Huan Wang.

64 records · Page 4Linked to original sources
PubMed2003

Cooling and rewarming for brain ischemia or injury: theoretical analysis.

A three-dimensional model is developed in this study to examine the transient and steady state temperature distribution in the brain during selective brain cooling (SBC) and subsequent rewarming. Selective brain cooling is induced through either wearing a cooling helmet or packing the head with ice. The ischemic region of the brain is simulated through reducing the blood perfusion rate to 20% of its normal value. The geometric and thermal properties and physiological characteristics for each layer, as well as the arterial blood temperature, are used as the input to the Pennes bioheat equation. Our data suggest that rapid cooling of the brain gray matter can be achieved by SBC on the head surface (26 min for adults versus 15 min for infants). Suboptimal thermal contact between the head surface and the coolant in most commercially available cooling helmets is suspected to be the main reason for delayed cooling in SBC as compared to the ice packing. The study has also demonstrated that the simulated 3 degrees C/h passive rewarming rate by exposing the head to room temperature after removing the source of cooling may be too rapid.

Adult↗
PubMed2003

Screening of chemopreventive tea polyphenols against PAH genotoxicity in breast cancer cells by a XRE-luciferase reporter construct.

Polycyclic aromatic hydrocarbons (PAHs) are established cancer initiators that can be found in our food and environment. Some dietary plant polyphenols are strong inhibitors to PAH-induced mutagenesis, whereas others may not be as effective. To identify the chemopreventive compounds from a huge volume of dietary components, the development of an efficient screening method is required. In this study, a xenobiotic response element (XRE)-luciferase reporter plasmid was constructed to screen for some potential chemopreventive agents in tea against PAH-induced DNA damage. Tea is one of the most consumed beverages worldwide, and its beneficial effects on health have been documented. Previous studies have claimed that tea polyphenols could be protective against various cancers, and the rich database can be a source for comparison. Among the green and black tea polyphenols, the XRE-luciferase reporter assays suggested that only epigallocatechin gallate (EGCG) was effective in reducing XRE-driven luciferase assay in MCF-7 cells at the concentrations tested. Further study indicated EGCG could reduce CYP1A1 and CYP1B1 mRNA abundances and decrease the DMBA-DNA lesions. The results of DNA covalent binding of all tea polyphenols tested were consistent with the XRE-reporter assays. This study illustrated that the XRE-reporter assay was a viable screening test for dietary chemopreventive agents against PAH-initiated breast mutagenesis. It has the advantages of shorter sample processing time and producing no radioactive waste over directly measuring the CYP1A1/1B1 expressions, DNA lesion, or gel mobility shift assay.

Analysis of Variance↗
PubMed2003

Urgent endovascular treatment of acute symptomatic occlusion of the cervical internal carotid artery.

OBJECT: The prognosis of patients with acute symptomatic cervical internal carotid artery (ICA) occlusion is generally considered to be poor. Traditionally, such patients are not considered eligible for urgent thrombolytic/endovascular treatment. Since 1998, an aggressive therapeutic approach with endovascular treatment has been adopted at the authors' institution. In this report they assess whether aggressive treatment of ICA occlusion is appropriate. METHODS: The clinical characteristics and outcome of six consecutive patients treated urgently with an endovascular approach between 1998 and 2001 are reviewed and summarized. Recanalization was accomplished in all patients. At a mean follow-up period of 8 months (range 2-14 months), five of six patients had good or excellent outcomes (modified Rankin Scale [mRS] Score 0-1) and one had a poor outcome (mRS Score 4). CONCLUSIONS: With recent advancements in thrombolytic and endovascular treatments, an aggressive endovascular approach in patients with acute symptomatic cervical ICA occlusion may be successful. Further clinical data are required to determine the optimal endovascular approach in these patients.

Acute Disease↗
PubMed2003

Provocative test occlusion or the Matas test: who was Rudolph Matas?

Temporary occlusion of large vessels (the Matas test) to test the adequacy of collateral circulation is part of daily clinical practice. Nevertheless, only a few clinicians are aware of Rudolph Matas and his pioneering work in different fields of medicine. A legendary New Orleans surgeon, Rudolph Matas (1860-1957) lived nearly a century. During that time he witnessed enormous progress in medicine and greatly contributed to its evolution. He is unanimously recognized as the father of modem vascular surgery for his creation and popularization of aneurysmorrhaphy, a technique for the definitive treatment of aortic and peripheral aneurysms. He also made significant contributions to the then burgeoning fields of anesthesia, critical care, and infectious disease (yellow fever in particular). In 1911, he wrote a landmark article in which he described a challenge test to assess the degree and efficacy of the collateral circulation in patients under consideration for permanent occlusion of a major vessel. Matas studied the feasibility of such a test by temporarily occluding the carotid and femoral arteries in dogs for variable periods of time. In the introduction to his seminal article on the subject, he stated that "the chief object of this inquiry has been to determine whether the large arteries can be occluded long enough to make it possible to observe the effect of the arrested circulation in the territory supplied by the occluded vessel, without irreparably damaging the artery during the period of observation." He definitively achieved his stated goal: the Matas test, although greatly modified by contemporary endovascular techniques to be safer and more reliable, is in essence still routinely performed worldwide 90 years after its initial description.

Eponyms↗
PubMed2002

Secondary surgery after digit replantation: its incidence and sequence.

This article discusses the incidence and sequence of secondary procedures following digital replantation. In published series addressing this topic, the overall frequency of postreplantation surgery ranged from 2.9-93.2%. Tendon procedures accounted for 47.2% of cases, and comprised the leading type of secondary operations. Tendon procedures were followed by joint procedures (18.9%), skeletal stabilization (12%), skin coverage (11.4%), nerve reconstruction (8.9%), and late amputation (1.6%). The number of secondary procedures per patient averaged from 1-4.5, depending on prioritization of different procedures. The order of restoration procedures should be as follows: supple skin coverage, skeletal stability, and protective and proprioceptive sensation. Joint reconstruction follows these procedures, which in turn is followed by tendon reconstruction.

Female↗
PubMed2002

Experimental study of vibrational behavior of laminated annular disks.

The purpose of this paper is to present an experimental study of the vibrational behavior of laminated annular disks, and effects of laminations on the vibrations of the disks. The vibrations of a series of solid annular disks were calculated using the finite-element method in order to provide a basis for comparison with experimental data. An extensive range of experiments was performed on both a series of solid disks and a series of laminated disks under a range of normal clamping pressures. Based on the calculated and experimental results, it was found that the vibrational behavior of the laminated disks was dominated by that of the individual disk, of which the laminated disks were composed. Laminations had great effects on the vibrational behavior of the laminated disks and the effects depended upon the mode type, the clamping pressure, and the number of disk assembly. Laminations increased damping and reduced the amplitude of frequency response function for both the transverse modes and in-plane modes of disks. The resonant frequency of transverse modes shifted higher because of the effects of laminations. For the in-plane vibrational modes, the effects on the resonant frequency could be neglected and the resonant frequency could be considered to be a constant.

Journal Article↗
PubMed2002

Long term outcome of contralateral C7 transfer: a report of 32 cases.

OBJECTIVE: To observe long-term functional recovery after contralateral C7 transfer. METHODS: From August 1986 to July 2000, 224 patients with brachial plexus avulsion injuries were treated with contralateral C7 transfer in our department. Thirty-two patients were followed up for over 2 years for evaluation of the following items: 1 influence on healthy limb function; 2 sensory and motor recovery of the recipient nerves in the affected limb; and 3 coordination between the healthy and affected limbs. RESULTS: There was no impairment of healthy limb function. Functional recovery of the recipient area reached > or =M3 in 8 patients (8/10, 80%) after musculocutaneous nerve neurotization, > or =M3 in 4 patients (4/6, 66%) after radial nerve neurotization, > or = M3 in 7 patients (7/14, 50%) and > or = M3 in 12 patients (85.7%) after median nerve neurotization, and > or = M3 in 1 patients (1/2, 50%) after thoracodorsal nerve neurotization. Synchronic contraction of the affected limb with the healthy limb occurred within 2-3 years in 12 patients, within 5 years in 13 patients, and over 5 years in 7 patients. CONCLUSION: Contralateral C7 transfer is an ideal procedure for the treatment of brachial plexus root avulsion injury. Selection of the whole root or the posterior division as neurotizer and a staged operation are the major factors influencing treatment outcome.

Adolescent↗
PubMed2000

Study on clinical application of selective transfer of ipsilateral C(7) nerve root.

OBJECTIVE: To verify the rationality, reliabilit y and practicability of selective transfer of ipsilateral C(7) nerve root for tr eatment of upper trunk avulsion. METHODS: Selective transfer of ipsilateral C(7) nerve root was ca rried out in 8 patients (7 with upper trunk avulsion, and 1 with left upper trun k avulsion combined with partial injury of the middle trunk) from June 1996 to F ebruary 1997. Selective transfer of the anterior division or the anteriolateral fascicles of the anterior division of ipsilateral C(7) to the anterior division of the upper trunk was performed under general anesthesia. Only 5 cases were fol lowed up. RESULTS: Among these 5 cases, effective recovery was observed o n 4 cases of the transfer of the anteriolateral fascicles of ipsilateral C(7) to the anterior division of the upper trunk. Electromyographic examination showed nerve regeneration could be observed in the 2nd month postoperatively. And detec table elbow flexion by biceps contraction was found in the 4th month postoperati vely. The function of the C(7) innervating muscles was not jeopardized, and the case with combined partial C(7) root injury had a poor result. CONCLUSIONS: Selective transfer of ipsilateral C(7) nerve root leads to a restoration of reinnervating muscle functions without affecting the f unction of the muscles innervated by C(7). It is therefore a practicable new sur gical procedure for treating upper trunk avulsions.

Journal Article↗
PubMedDate not supplied

Pharmacokinetics, tissue distribution and excretion of vinflunine.

The plasma pharmacokinetics, tissue distribution, excretion and binding to plasma proteins of vinflunine, were investigated after intravenous (iv) administration. We obtained plasma profiles after iv administration of vinflunine at the doses of 3.5, 7 and 14 mg/kg in rats. The t1/2 values for vinflunine were estimated to be 18.38+/-1.20, 17.05+/-0.77, 18.35+/-1.57 h, and the mean AUC0-t values were 3.48+/-0.38, 6.54+/-0.68, 12.79+/-2.93 microg x h/ml, respectively. Of the various tissues tested, vinflunine was widely distributed into tissues, with the highest concentrations of vinflunine being found in well perfused organs. Maximal concentration of vinflunine was reached at 0.5 h postdose in the majority of tissues. In tumor-bearing mice, the similar pattern of tissue distribution was observable, except that vinflunine can be distributed into tumor. The binding of vinflunine in human and rat plasma proteins were 39.6% and 58.4% respectively. Within 96 h after administration, 9.58%, 15.36% and 0.71% of the given dose was excreted in urine, feces and bile, respectively. In conclusion, Vinflunine had a longer terminal half-life, a wide tissue distribution and less than 25% of the given dose was excreted as unchanged drug, suggesting metabolism as a major style of elimination.

Animals↗