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Biomedical subjects

L Zhou

Publications and source records attributed to L Zhou.

At least 109 records · Page 6Linked to original sources
PubMed2001

Longitudinal analysis of leisure-item preferences.

Twenty-two individuals with developmental disabilities participated in two leisure-item preference assessments, spaced approximately 16 months apart. Results showed (a) an overall increase in item contact across assessments for 13 participants and (b) at least some overlap across assessments in the five most highly ranked items for every participant. These results highlight individual differences in the stability of preference over time and suggest the need for research to identify the determinants of temporal shifts in preference.

Adult↗
PubMed2001

Adenoviral vector-mediated gene transfer for human gene therapy.

Human gene therapy promises to change the practice of medicine by treating the causes of disease rather than the symptoms. Since the first clinical trial made its debut ten years ago, there are over 400 approved protocols in the United States alone, most of which have failed to show convincing data of clinical efficacy. This setback is largely due to the lack of efficient and adequate gene transfer vehicles. With the recent progress in elucidating the molecular mechanisms of human diseases and the imminent arrival of the post genomic era, there are increasing numbers of therapeutic genes or targets that are available for gene therapy. Therefore, the urgency and need for efficacious gene therapies are greater than ever. Clearly, the current fundamental obstacle is to develop delivery vectors that exhibit high efficacy and specificity of gene transfer. Recombinant adenoviruses have provided a versatile system for gene expression studies and therapeutic applications. Of late, there has been a remarkable increase in adenoviral vector-based clinical trials. Recent endeavors in the development of recombinant adenoviral vectors have focused on modification of virus tropism, accommodation of larger genes, increase in stability and control of transgene expression, and down-modulation of host immune responses. These modifications and continued improvements in adenoviral vectors will provide a great opportunity for human gene therapy to live up to its enormous potential in the second decade.

Adenoviridae↗
PubMed2001

Effects of diaspirin cross-linked hemoglobin (DCLHb) during and post-CPR in swine.

The purpose of the study was to test the hypothesis that diaspirin cross-linked hemoglobin (DCLHb) can produce improved resuscitation during cardiac arrest. DCLHb, a derivative of human hemoglobin, has previously been demonstrated to produce a vasopressor response that is associated with increased blood flow to vital organs. In addition, it is an oxygen carrier. These effects may be beneficial to extreme low flow states, such as that during cardiac arrest and cardiopulmonary resuscitation (CPR). Experimental cardiac arrest and CPR were carried out in 32 anesthetized immature pigs. In each animal, ventricular fibrillation was induced for 5 min, followed by 10 min of standard CPR with a pneumatic device and room air ventilation. High (15 ml/kg) and low (5 ml/kg) doses of DCLHb or equivalent volume of normal saline were infused at the beginning of CPR in a random and blind manner. Cardiac output, organ blood flow, aortic pressure, coronary perfusion pressure, blood gases, and lactate concentrations were obtained before and during CPR. Following the 10-min CPR, the animals were defibrillated and the return of spontaneous circulation (ROSC) determined. DCLHb treatment achieved 75% ROSC compared with 25% in the saline group (p < 0.05). In addition, a better (p < 0.05) myocardial O(2) delivery, venous blood O(2) content, and myocardial and cerebral perfusion pressure were observed in the DCLHb group. DCLHb treatment during cardiac arrest and CPR significantly improves ROSC. This is most likely related to its improvement in coronary perfusion and myocardial oxygen delivery.

Animals↗
PubMed2001

[The vectorial algorithm for articulate motion of human entities].

The human moving system is defined as a rigid frame, which contains 19 articulate entities. Entity rotates around the father node and its son node is the father of another entity at the next level. The human frame is divided into 5 entity links. Through the vector summation algorithm and along the link, each entity's father nodes are calculated successively, and the vectorial frame of human posture is constructed. With all the entity patterns pasted on the vectorial frame, the picture of human moving posture is drawn.

Algorithms↗
PubMed2001

[The technical method for noninvasive magnetic stimulation of nerve center and its clinical application].

The increasing use of non-invasive magnetic stimulation technique for nerve center function examination and functional neuromuscular rehabilitation is a new cynosure in biomedical engineering and neuro-electrophysiologic researches. This paper analyzes theoretically the magnetic stimulation of first demonstration extending the technique model to human body, and the magnetic principle of physics. The characteristics of magnetic stimulation can be highlighted by comparing it to conventional electrical stimulation. Also presented are the peripheral multichannel magnetic stimulation to mimic electrical stimulation and the clinical functions toward neuromuscular rehabilitation.

Central Nervous System↗
PubMed2001

Discovery of the first non-peptide antagonist of the motilin receptor.

A first-in-class non-peptide antagonist of the motilin receptor was identified through electronic screening of our corporate database against a 3D pharmacophore. The pharmacophore was developed from the motilin 22 residue endogenous peptide using NMR structural data, principles of peptide folding, and peptide structure activity relationships. The NMR data supported helical content within the peptide, and both the hydrophobic staple and N-capping box motifs were identified in the motilin sequence. The conformational features of these motifs were imposed on the peptide structure, providing a constrained conformer as a starting point for database searching. A trisubstituted cyclopentene lead was identified directly from the electronic search. Compounds in this series inhibit the binding of 125I-motilin to human antral smooth muscle membrane and antagonize motilin-induced intracellular calcium mobilization in cells expressing the human motilin receptor. A potent compound developed through optimization, RWJ 68023, is active in binding and cell-based functional assays and is also effective in inhibiting motilin-induced contractility in segments of rabbit duodenum. This orally active compound is currently undergoing clinical evaluation for the treatment of gastrointestinal disorders associated with altered motility.

Amino Acid Sequence↗
PubMed2001

[Changes in expression of angiotensin subtype AT1A and AT2 receptors in rats during cardiac remodeling following myocardial infarction].

Immunohistochemical and electron microscopic techniques and image analysis were employed to investigate the regulation of cardiac AT1A and AT2 subtype receptors in rats during cardiac remodeling following myocardial infarction (MI). Positive immunostaining for AT1A and AT2 receptors was observed in myocytes and vessels with AT1A being more than AT2. Three days after MI, disappearance of myocardial cross striation and fibroblast hyperplasia were found with electron microscopy. AT1A receptor protein expression in myocardial noninfarcted portion notably increased compared with that in sham-operated control rats (P < 0.001). No apparent changes were observed in AT2 receptor (P > 0.05). Two weeks after MI, myocyte cross striation and collagen deposition were found. Meanwhile, AT1A receptor staining decreased compared with that of three days after MI (P < 0.01), but there was still more than that of the control (P < 0.05). AT2 receptor was significantly increased compared with that of the sham-operated control rats (P < 0.001). These results suggest that both AT1A and AT2 receptor protein expression was upregulated in noninfarcted myocardium after MI, and the regulation of AT1A and AT2 receptors after MI may be involved in post-infarction cardiac remodeling.

Animals↗
PubMed2001

Depentylation of the rat esophageal carcinogen, methyl-n-pentylnitrosamine, by microsomes from various human and rat tissues and by cytochrome P450 2A3.

Methyl-n-pentylnitrosamine (MPN) is carcinogenic for the rat esophagus. To determine organ specificity for MPN activation by human tissues, microsomes isolated from human organs (snap-frozen <6 h after death or removed surgically) were incubated with [pentyl-(3)H]MPN, and [(3)H]pentaldehyde formation was measured by high-pressure liquid chromatography of its 2,4-dinitrophenylhydrazone using radioflow assay. With 100 microM MPN, mean depentylation rates were 6.6 (liver), 2.9 to 3.8 (kidney, stomach, small intestine, and colon), and 0.4 to 1.6 (esophagus, lung, and skin) pmol of pentaldehyde/mg of protein/min. Of 14 human esophagi, four showed relatively high depentylation rates of 3.3 to 4.1 pmol/mg/min. Apparent K(m) was 80 to 160 microM (V(max), 3-15 pmol/mg/min) for three esophagi, 90 to 130 (2 livers), and 1330 (1 kidney) microM. Rat tissues showed mean depentylation rates for 100 microM MPN of 24.9 (liver), 14.5 (esophagus), 7.0 (lung), and 0.0 to 2.7 (5 other tissues) pmol/mg/min. MPN depentylation by rat cytochrome P450 2A3 showed an apparent K(m) of 8 microM (V(max), 70 pmol/nmol of P450/min) and was competitively inhibited by the CYP2A inhibitor coumarin (apparent K(i), 4 microM). Coumarin (0.4 mM) inhibited microsomal depentylation of 100 microM MPN by 37 to 62% for human esophagus, liver, kidney, and colon and for rat esophagus but not for rat liver and lung. MPN depentylation by rat esophageal microsomes increased up to 90% on adding P450 reductase. The results indicate organ-specific MPN metabolism by rat but not human esophagus. Nevertheless, the relatively high activity of four human esophagi might indicate increased susceptibility of some individuals to carcinogenesis by unsymmetrical dialkylnitrosamines.

Adult↗
PubMed2001

[Continuous measurement of baseline atmospheric carbon monoxide in western China].

In-situ custom-designed gas chromatography(GC)-HgO system was established for the continuous measurement of atmospheric CO at Waliguan Baseline Station(36 degrees 17' N, 100 degrees 54' E, 3816 m asl) in western China. The system's assembling, testing, running and calibration indicated that the chromatographic method has stable baseline and high separation efficiency, as well as reliable detection method. This system adopted high automatic operating techniques and followed strict quality control. It is up to the standard of WMO's baseline watch on global atmosphere. According to the flask sampling results of in-situ CO variation at Waliguan, CO standards in clean dry air under international comparison were used to determine the adjustable working standard curves, so as to calculate the ambient CO mixing ratios based on peak height. This system's detection limit for CO is around 1 x 10(-9) (V/V), the precision is below 0.1% and accuracy in +/- 0.05%, it can provide continuous and accurate surface CO mixing ratios in baseline areas of China.

Air↗
PubMed2001

Sources of eicosanoid precursor fatty acid pools in tissues.

Tissue arachidonic acid (AA) pools originate from the diet, and from hepatic and extrahepatic desaturation-elongation of dietary linoleic acid (LA). This review summarizes the roles of absorption, transport, and formation of AA in the buildup of tissue AA pools. In humans who ingest 0.2-0.3 g of AA and 10-20 g of LA per day on a Western diet, the formation of AA from LA exceeds the dietary supply of AA. A number of factors favor the partitioning of AA to tissue phospholipids rather than adipose tissue and plasma triglycerides. The characteristics of AA transport with lipoproteins are discussed with focus on the role of lipoprotein lipase, lecithin:cholesterol acyltransferase, hepatic lipase, and the scavenger receptor BI and LDL receptors in tissue uptake of AA. Liver-derived 2-acyl-lysophosphatidylcholine and plasma free AA are two important sources of AA for extrahepatic tissues which exhibit a low rate of uptake of lipoprotein AA. Desaturation-elongation of LA to produce AA occurs both in liver and in extrahepatic tissues, plasma free LA being an important substrate particularly during fasting. The AA preference of the reacylation and transacylation reactions is crucial for the selective retention of AA in phospholipids.

Acylation↗
PubMed2001

[Study on the timing of cerebral hemorrhage attacks].

This study sought to disclose the circadian rhythmicity of cerebral hemorrhage attacks. We defined every two hours as a period of time from zero hour, investigated the attacks of 364 cerebral hemorrhage patients in each period, and analyzed the attack time, the sites of hemorrhage, the presence or absence of hypertension and the relevant treatments. The results revealed an obvious time difference of cerebral hemorrhage attacks with the peak time of incidence in the 6:00-12:00 periods, the medium in the 16:00-18:00 periods, the lowest in the 22:00-6:00 periods. The sites of cerebral hemorrhage were found to be related with the attack time. The peak time of cerebral hemorrhage in basalganglia was seen in the 8:00-12:00 periods and that of cerebral hemorrhage in non-basalganglia in the 16:00-20:00 periods. The variable about hypertension and relevant treatment was also found to be closely related to the attack time of cerebral hemorrhage. The patients who had contracted hypertension and had not been treated were liable to have hemorrhage attack in the 16:00-20:00 periods, but those who had been treated or had normal blood pressure usually had attacks in the 8:00-12:00 periods. In conclusion, cerebral hemorrhage attack is periodic. The attack time is closely related to the sites of cerebral hemorrhage, the presence or absence of hypertension and the relevant treatment.

Aged↗
PubMed2001

[Identification of Amomum villosum, Amomum villosum var. xanthioides and Amomum longiligulare on ITS-1 sequence].

OBJECTIVE: To identify Amomum villosum Lour. and some their adulterants on molecular biology. METHOD: The DNA of Amomum villosum Lour. and some their adulterants were extracted, and amplified using ITS-1 primer. The amplificed DNA were purified and then sequenced by direct PCR sequencing method. RESULT: The ITS-sequence of all of the samples are 248 bp in size. But there are 7 bases in Amomum villosum Lour var. xanthioides (Wall.ex Bak) T.L. Wu et Senjen and 12 hases in Amomum longiligulare T.L. Wu. differing from Amomum villosum Lour. CONCLUSION: The ITS-1 sequence can be used to identify effectively Amomum villosum Lour. and their adulterants.

Amomum↗
PubMed2001

Effects of microinjection of melatonin and its receptor antagonists into anterior hypothalamic area on blood pressure and heart rate in rats.

AIM: To examine the effects of microinjection of melatonin and its receptor antagonists into the anterior hypothalamic area (AHA) on blood pressure (BP) and heart rate (HR) in normotensive and stress-induced hypertensive rats. METHODS: Melatonin and its receptor antagonists were microinjected into the AHA, then BP, mean arterial pressure (MAP), and HR were synchronously recorded. RESULTS: Microinjection of melatonin produced a fall in MAP. Prazosin, an antagonist of melatonin ML2 receptor, could not antagonize the depressive response induced by melatonin. While luzindole, a competitive antagonist of melatonin ML1 receptor, was able to almost completely prevented the depressive response induced by injection of melatonin. CONCLUSION: Melatonin acts as a hypotensive factor and the effects are mainly due to activation of ML1 receptors in rat brain, and the AHA may be one of the important central areas where melatonin can exert modulatory effects on BP and HR.

Animals↗
PubMed2001

[Brain-stem cavernous hemangioma: surgical indications and approaches].

OBJECTIVE: To evaluate the surgical indications and prognosis for cavernous hemangiomas (CHs) in the brain-stem. METHODS: From 1992 to 2000, 163 patients with intracranial CHs were operated on in our department. Among them, 14 patients (8 women and 6 men; mean age 42 years) had 15 CHs in the pons (12), mesencephalon (1) and medulla oblongata (1). Surgical indications for CHs are: progressive focal neurological deficits; hemorrhage; near the surface of the brainstem. Transvemian approach with midline suboccipital craniotomy was used for the lesions in the pons and medulla, near the floor of the IV cerebral ventricle. Transpetrosal approach was used for the lesions in the anterior part of the pons, and infratentorial supracerebellar approach for those in the mesencephalic case. RESULTS: CHs were totally removed from all the 15 lesions. Neurological deficits were improved in 10 patients after operation. Two patients had transient worsening of neurological conditions, which returned to the preoperative status during follow-up. The mesencephalic case, however had neurological condition deteriorated and was homebound after surgery. Pathologically, an oligodendroglioma was seen with CH in this case. CONCLUSIONS: If surgically indicated, CHs involving the brain-stem can be resected. Minimal invasiveness techniques and careful operative planning may contribute to the treatment of CHs involving the brain-stem.

Adolescent↗
PubMed2001

[Association of beta 3-adrenergic receptor gene with obesity in patients with type 2 diabetes mellitus].

OBJECTIVE: To investigate the association between the mutation of beta 3-adrenergoc receptor gene and obesity in patients with type 2 diabetes. METHODS: Body mass, waist-hip ratio, blood pressure and blood lipids were measured in 154 type 2 diabetic patients. Polymerase chain reaction and the restriction fragment length polymorphism analysis were used to determine the wild, heterozygous and homozygous forms of beta 3-adrenergoc receptor gene. RESULTS: The frequency of the Trp64Arg mutation was 42.5% and the frequency of Arg64 allele was 22.6%. The mutation frequency of the genetic types was significantly different between the obese and non-obese type 2 diabetes mellitus patients. The body mass, systolic blood pressure, diastolic blood pressure, HDL-cholesterol were significantly different, when those with Trp64Arg heterozygous were compared with those with Trp64 homozygous. CONCLUSIONS: The genetic mutation of beta 3-adrenegoc receptor in patients with type 2 diabetes is probably related to obesity.

Adult↗
PubMed2001

[Treatment of pleural effusion caused by lung carcinoma with circular intrapleural hyperthermic perfusion and its mechanism].

OBJECTIVE: To assess the comprehensive effectiveness of intrapleural hyperthermic perfusion in treatment of malignant pleural effusion (MPE) caused by lung carcinoma and to explore its nechanism. METHODS: 45 patients with MPE caused by lung carcinoma underwent circular intrapleural hyperthermic perfusion with 43 warmed normal saline for 60 minutes. Response of pleural effusion and the original lung tumor, sife-effects, life qualty and survival time of the patients were followed up. Flow cytometry, optical microscopy, electron microscopy, and TUNEL method were used to compare the cytology and biochemistry of pleural effusion and cancer cells planted to the surface of pleura before and after the therapy. RESULTS: The control rate of pleural effusion was 100% (CR 93.3%, PR 6.7%). No recurrence of pleural effusion was observed in 44 cases. Pleural effusion reoccured 12 months after the thermotherapy in one case. The time without pleural effusion lasted 16.5 months on average with the longest time of 40 months. CT performed one month after the thermotherapy in 13 cases showed that the primary focus in lung dwindled in 13 cases, and remained unchanged in 5 cases. Neither operative death nor post-operative complication was found. The life quality was improved in all the cases. The medium survival time was 16.8 months. One-year survival rate was 87%. One case survived more than 3 years, 4 cases survives more than 2 years (29, 30, 31, and 40 months respectively). Carcinoembryonic antigen decreased to normal and no carcinoma cell was found in pleural effusion. Flow cytometry showed that the tumor heteroploid peak diasappeared. Pyknosis and disintegration of nuclei, and apoptotic bodies of tumor cells planted on the surface of pleura were found by optical and electron microscopy. TUNEL showed apoptotic cells with brilliant yellow fluorescence. CONCLUSION: (1) Circular intrapleural hyperthermic perfusion is a new, safe, and effective treatment for MPE. (2) Apoptosis-mediated cytocidal function, improvement of body immunity after hyperthermic perfusion and continuous wash of the perfusion fluid are important mechanisms of intrapleural hyperthermic perfusion in treatment of MPE caused by lung carcinoma.

Adult↗