Biomedical subjects

H Guo

Publications and source records attributed to H Guo.

At least 109 records · Page 6Linked to original sources

PubMed2000

Pharmacokinetics of the fluocinolone/5-fluorouracil codrug in the gas-filled eye.

PURPOSE: To determine the effect of intraocular gas tamponade on drug levels achieved with the intravitreal sustained-release fluocinolone (FL)/5-fluorouracil (5-FU) codrug pellet. METHODS: After insertion of a 10-mg codrug pellet into the right eyes of 43 New Zealand white rabbits, perfluoropropane (0.4 mL of 100% C3F8) or a control sham was then injected into the midvitreous cavity. On postoperative days 2, 4, 7, 21, and 42, aqueous samples were collected, the rabbits were killed, and the right eyes were enucleated. The vitreous and remaining codrug pellet were then isolated. Pellet and intravitreal drug levels were determined by high-pressure liquid chromatography. RESULTS: No measurable drug levels were detected in any of the aqueous samples. Maximal gas expansion occurred by day 4 and partial resorption was observed by days 14 to 21. Vitreous FL and 5-FU levels during C3F8 expansion (day 2) were statistically significantly higher in the gas-filled eyes. On postoperative days 4, 7, 21, and 42, there were no statistically significant differences between FL and 5-FU drug levels in eyes containing C3F8 as compared with control eyes. Pellet codrug, FL, and 5-FU levels over time were similar in gas-filled and control eyes. CONCLUSIONS: Intraocular gas tamponade does not significantly affect the sustained intravitreal drug levels achieved with the FL/5-FU codrug. If clinically efficacious, the FL/5-FU codrug formulation does not need to be altered to treat proliferative vitreoretinopathy in the presence of intraocular gas.

Animals↗

PubMed2000

Safety and pharmacokinetics of an intraocular fluocinolone acetonide sustained delivery device.

PURPOSE: To determine the safety and pharmacokinetics of an intraocular fluocinolone acetonide sustained drug delivery device. METHODS: Nonbiodegradable drug delivery devices containing 2 or 15 mg of a synthetic corticosteroid, fluocinolone acetonide, were constructed. The long-term in vitro release rates of these devices were determined in protein-free buffer or buffer containing 50% plasma protein. Fifteen-milligram devices were also implanted into the vitreous cavities of rabbit eyes. Intravitreal drug levels, the amount of drug remaining in explanted devices, and the release rate of explanted devices were determined over a 1-year time period. Drug toxicity was assessed over this same time period by slit lamp examination, indirect ophthalmoscopy, electroretinography, and histologic examination. RESULTS: The drug release rates for the 2-mg device, 1.9 +/- 0.25 microg/d, and for the 15-mg device, 2.2 +/- 0.6 microg/d, remained linear over the 6-month and 45-day testing period, respectively. The release rate increased by approximately 20% when devices were transferred from protein-free buffer to buffer that contained protein (P: < 0.0001). Vitreous levels remained fairly constant (0.10-0.21 microg/ml) over a 1-year period. No drug was present in the aqueous humor during this time period. Based on the device release rates, the predicted life span of the 2- and 15-mg devices are 2.7 and 18.6 years, respectively. There was no evidence of drug toxicity by clinical examination, electroretinography, or histologic examination. CONCLUSIONS: It is feasible to construct a nontoxic fluocinolone acetonide drug delivery device that reproducibly releases fluocinolone acetonide in a linear manner over an extended period. These devices show great promise in the treatment of ocular diseases such as uveitis, which are often managed with chronic corticosteroid therapy.

Animals↗

PubMed2000

Release of the neuronal glycoprotein ICAM-5 in serum after hypoxic-ischemic injury.

Intercellular adhesion molecule (ICAM)-5 (telencephalin) is unique among the ICAMs, because it is only expressed in somatodendritic membranes of telencephalic neurons. To investigate the fate of ICAM-5 during focal brain injury, we induced hypoxia-ischemia (HI) damage in adult mice by right common carotid artery ligation followed by hypoxia. ICAM-5 was detectable in serum within a 48-hour window after HI injury. In HI brain, dendritic ICAM-5 immunore-activity was abolished, but it was present in the neuropil and soma of hippocampal pyramidal, dentate granule, and some cortical and striatal neurons. After HI injury, levels of ICAM-5 protein and messenger RNA initially increased, and ICAM-5 messenger RNA expression then decreased, although protein levels continued to increase. Because HI injury induces microglial activation with increases in CD11a/CD18 (lymphocyte function antigen [LFA]-1) counterreceptors to ICAM-5, we investigated whether modulation of interactions between LFA-1 receptors and brain ICAM-5 during HI injury are associated with changes in levels of serum ICAM-5. Intracerebroventricular administration of lipopolysaccharide to activate microglia before HI injury resulted in elevated serum ICAM-5 levels compared with those in mice with only HI injury. Pretreatment with anti-LFA-1 antibodies before HI injury or LFA-1 receptor knockout mice with HI injury had markedly reduced levels of serum ICAM-5. Lipopolysaccharide levels increased, whereas LFA-1 receptor blockade or LFA-1 knockout decreased HI injury in the first 12 hours. These data suggest that during the necrotic phase of HI injury, serum ICAM-5 may be a potential marker for somatodendritic neuronal damage.

Animals↗

PubMed2000

Complete sequence and organization of Periplaneta fuliginosa densovirus genome.

The replicative form (RF) of the Periplaneta fuliginosa densovirus (PfDNV) genome was cloned and its complete nucleotide sequence was determined. The PfDNV genome is 5454 nucleotides (nt) in length with distal 201-nt long inverted terminal repeats (ITRs). The first 122 nt at the 5'-end and the terminal 122 nt at the 3'-end of both strands are palindromes with identical sequences, of which each can fold into a typical U-shaped hairpin structure. The coding regions of PfDNV genome are evenly distributed in the 5'-halves of both strands. PfDNV genome contains seven major open reading frames (ORFs), four of which on the plus DNA strand may encode non-structural (NS) proteins, while the others on the minus DNA strand may encode structural proteins. Two potential functional promoters (P3 and P97) were found within the ITRs on both strands. The ORF2 polypeptide contains a highly conserved NTP-binding domain of NS proteins of parvoviruses. The ORF5 polypeptide has significant homology to the conserved PGY region of coat proteins of parvoviruses. The ORF6 polypeptide has distinct homology to the structural polypeptides of insect parvoviruses. The organization of PfDNV genome was compared to those of other parvoviruses.

Amino Acid Sequence↗

PubMed2000

Epidemiologic study of the irritable bowel syndrome in Beijing: stratified randomized study by cluster sampling.

OBJECTIVE: To explore the prevalence of irritable bowel syndrome (IBS) in Beijing and its risk factors. METHODS: Phase I: a screening for IBS in Beijing area according to symptoms using both Manning (modified including constipation) and Rome criteria. 2486 subjects were studied by cluster sampling of the inhabitant groups according to a stratified design of urban, suburban and rural areas, and sample size of each area studied was in proportion to the population of the area. Selection of the inhabitant groups was made by simple random sampling. Age of subjects enrolled in the study was 18-70 years. All subjects fulfilling the selection criteria were requested to fill in a questionnaire assisted by trained doctors or medical students during the visit to their families. Phase II: an aliquot of patients who fulfilled at least the Manning criteria were further selected according to their scoring series to undergo detail clinical examination in the hospital including laboratory examination, abdominal ultrasonography, colonoscopy or/and barium enema to exclude organic disease of the colon. Prevalence of IBS of the population was then adjusted by the rate of correct diagnosis during Phase II study. Study using Minnesota Multi-Personality Indices (MMPI) was done in some cases. Probable risk factors were explored by comparing their frequencies among IBS group and non-IBS group using chi 2 and logistic analysis of multifactors. RESULTS: The adjusted point prevalence of IBS in Beijing is 7.26% according to Manning criteria, and is 0.82% according to Rome criteria. There is a higher prevalence rate in city (10.50%) than in rural areas (6.14%) by stratified analysis (P < 0.001). Male to female ratio is 1:1.15. And IBS is more common in people aged between 18-40 years (51.6%), and among the intellectuals. Our study indicated that history of dysentery (OR 3.00), exposure to cool (OR 1.55) and ingestion of cold food and raw materials (OR 1.24) may be the most important risk factors (P < 0.001), and IBS patients may have a higher tendency of psychological abnormalities. CONCLUSION: IBS is a common disorder in Beijing and should be taken into consideration in the human welfare strategy.

Adolescent↗

PubMed2000

Different Wnt-5A gene expressions in the renal cell carcinoma GRC-1 cell line during the cell cycle.

OBJECTIVE: To investigate the gene expression at transcription level of growth factor Wnt-5A in different phase during the cell cycle. METHODS: We synchronized the renal cell carcinoma GRC-1 cell line by double thymidine blocks and high-pressure N2O gae methods and amplified Wnt-5A cDNAs from different phase using Semi-quantitative RT-PCR (reverse transcriptase polymerase chain reaction). The PCR products were electrophoresized on the agrose gel and detected by Gel Doc 1000 computer controlled system integrating the volumes of each band, representing the intensities of all pixels in a defined band. RESULTS: The different mRNA expressions of growth factor Wnt-5A was detected in RCC GRC-1 cell line. In S phase, the highest level of Wnt-5A transcript was observed, and in G1 and M phase, medial and lowest, respectively. The differences between S and M stages were statistically significant (P < 0.05). CONCLUSION: Growth factor Wnt-5A has the potential effect on tumorigenesis. It contributes to all phases during cell cycle but in S phase especially.

Carcinoma, Renal Cell↗

PubMed2000

Bilateral papilloedema associated with lumbo-sacral intraspinal tumor.

OBJECTIVE: To study the possible mechanism of bilateral papilloedema associated with intraspinal tumor at the lumbo-sacral level. METHODS: Three cases were reported. Detailed clinical history was evaluated. Patients were followed up for 2, 3 and 5 months after resection of the tumor. Related literature was reviewed. RESULTS: Papilloedema was soon resolved and the level of protein in the cerebrospinal fluid (CSF) decreased significantly after resection of tumor. These indicated a close relationship between papilloedema, CSF protein and intraspinal tumor. CONCLUSION: This is the first report of papilloedema associated with a lumbo-sacral intraspinal tumor in Chinese literature. The high level of protein in CSF may be the cause of both papilloedema and increased intracranial pressure. In patients with bilateral papilloedema, if no intracranial cause could be found, lumbo-sacral intraspinal tumor should be considered.

Adult↗

PubMed2000

[Study on the relation between hypertensive left ventricular hypertrophy in very old people with neurohormonal factors and ventricular arrhythmias].

OBJECTIVE: To study the relation between hypertensive left ventricular hypertrophy (LVH) in very old people (> 80 year) with neuro-hormone factors and ventricular arrhythmias. METHODS: Measurements were made on the heart rate variation, renin (Ren), angiotensin-II (AT-II), aldosterone (Ald), insulin (Ins), Holter and ambulatory blood pressure monitor in 60 cases of 2 groups: 30 with primary hypertension in very old people and LVH (group A); 30 with simple primary hypertension in very old people (group B). RESULTS: (1) There was no significant difference of AT-II and Ren among group A and B (P > 0.05); (2) Ins and Ald value in group A was much higher than group B (P all < 0.01); (3) Very lower frequency (VLF) and low frequency (LF) and LF/HF (high frequency) in group A were significantly higher than group B (P < 0.01, 0.05, 0.05, respectively); (4) incidence of premature ventricular beats and myocardial ischemia in group A were higher than those in group B. CONCLUSIONS: (1) Sympathetic nerve excitability in group A was greatly increased; (2) Hypertensive LVH were closely associated with Ald and Ins level, but not with AT-II and Ren; (3) There was obvious correction between group A and premature ventricular beats and ischemia.

Aged↗

PubMed2000

[A preliminary study of PSA level in 646 healthy men in Beijing].

OBJECTIVE: To evaluate the levels of total PSA (tPSA), free PSA (fPSA) and fPSA/t PSA ratio in healthy men in Beijing and analyze the relationship between age and PSA indexes. METHODS: Serum tPSA and fPSA were measured by electrochemi luminescence immune assay (ECLIA) and fPSA/t PSA ratio was calculated in 646 healthy men of 20 approximately 90 years old. The relationship between age and PSA indexes was analyzed by simple linear regression. RESULTS: In 20 approximately 30 years old cases, t PSA was 0.9 ng/ml +/- 0.6 ng/ml, fPSA was 0.27 ng/ml +/- 0.19 ng/ml and fPSA/t PSA ratio was 0.36 +/- 0.20. In 31 approximately 40 years old group, tPSA was 0.8 ng/ml +/- 0.6 ng/ml, fPSA was 0.22 ng/ml +/- 0.15 ng/ml and fPSA/tPSA ratio was 0.34 +/- 0.25. In 41 approximately 50 years old group, tPSA was 0.8 ng/ml +/- 0.6 ng/ml, fPSA was 0.21 ng/ml +/- 0. 14 ng/ml and fPSA/tPSA ratio was 0.34 +/- 0.23. In 51 approximately 60 years old group, tPSA was 1.0 ng/ml +/- 0.6 ng/ml, fPSA was 0.25 ng/ml +/- 0.15 ng/ml and fPSA/tPSA ratio was 0.31 +/- 0.19. In 61 approximately 70 years old group, tPSA was 1.0 ng/ml +/- 0. 7 ng/ml, fPSA was 0.25 ng/ml +/- 0.18 ng/ml and fPSA/tPSA ratio was 0.27 +/- 0.18. In 71 approximately 80 years old group, tPSA was 1.1 ng/ml +/- 0.7 ng/ml, fPSA was 0.31 ng/ml +/- 0.23 ng/ml and fPSA/tPSA ratio was 0.29 +/- 0.14. In 81 approximately 90 years old group, tPSA was 1.3 ng/ml +/- 1.1 ng/ml, fPSA was 0.4 ng/ml +/- 0.4 ng/ml and fPSA/tPSA ratio was 0.36 +/- 0.17. By univariate analysis, no correlation was found between serum PSA indexes and ages. CONCLUSIONS: The reference ranges of all PSA indexes in Chinese men may be lower than in that western men. There is no correlation between serum PSA indexes and ages. The reference range of 0 to 4 ng/ml used in the West may not be applicable to Chinese patients.

Adult↗

PubMed2000

[Analysis of social factors of pregnant women's cesarean section demands].

OBJECTIVE: To analyze the reasons of pregnant women's cesarean section demands. METHODS: Matched case-control study and questionnaire investigation were conducted. We analyze the cesarean section indications of pregnant women admitted to the Second and Third affiliated Hospitals of Beijing Medical University. Each section caused by pregnant woman's demand was matched with one vaginal delivery according to matching criteria. Questionnaires were used to analyze social characteristics of the two groups of women and find the reasons of women's cesarean section demands. RESULTS AND CONCLUSIONS: Incorrect knowledge of delivery, fear of delivery pain, lack of vaginal delivery confidence and doctors' talk with pregnant women about risks of delivery have significantly different (P < 0.05) influences on the two groups. Those are the four important factors of women's cesarean section demands.

Anxiety↗

PubMed2000

[Clinicopathologic study of patients with small cell carcinoma of the cervix].

OBJECTIVE: To study the clinicopathologic characteristics, diagnosis and treatment of small cell carcinoma of the cervix. METHODS: Eight patients with small cell carcinoma of the cervix were treated from May 1991 to December 1997 at Jiangxi Women's and Children's Hospital. Clinical data and follow-up records were retrospectively analyzed. RESULTS: Five patients had stage I(b) disease and 3 had stage II(b) disease. Seven patients underwent radical hysterectomy with pelvic lymph node dissection. One patient with stage II(b) disease was only treated with radiotherapy. Of the patients treated with operation, three showed pelvic lymph node metastases. Four patients who are alive free of the disease have been followed for 2, 13, 16 and 25 months, respectively. The survival intervals of 4 patients who died of the disease was 4, 5, 7 and 10 months, respectively. Of the death, one patient was only treated with radiotherapy, another had a very large cervical tumor and the two others complicated with pelvic lymph node metastases. CONCLUSIONS: Small cell carcinoma of the cervix is an aggressive tumor with a potentiality for early pelvic lymph node metastases and rapid recurrence, It is associated with higher mortality than any other cervical malignant neoplasms. It is able to make a right diagnosis with a combination of histopathologic and immunohistochemical characteristics.

Adult↗

PubMed2000

[An epidemiologic study of irritable bowel syndrome in Beijing - a stratified randomized study by clustering sampling].

OBJECTIVE: To explore the prevalence of irritable bowel syndrome (IBS) and its risk factors in Beijing. METHODS: Phase I: a screening program for IBS was carried out in Beijing area according to symptoms using both Manning (modified including constipation) and Rome criteria. Random clustered sampling involving 2 486 subjects of the inhabitants was carried out under stratification of city, suburban and rural areas. Sample size of each studied area was in proportion to the population of the area. The range of age was 18 - 70. All subjects studied were requested to fill in a questionnaire assisted by trained doctors or medical students during the visit to their families. Phase II: a small number of patients who fulfilled the Manning criteria were further selected to undergo detail clinical examination in the hospital including laboratory examination, abdominal ultrasonography, colonoscopy or/and barium enema to exclude organic disease of the colon. Prevalence of IBS of the population was then adjusted by the rate of correct diagnosis during phase II study. Minnesota Multi - Personality Indices was used in some cases. Potential risk factors were explored by comparing frequencies among IBS group and non - IBS group using chi(2) and logistic analysis of multifactors. RESULTS: The adjusted point prevalence of IBS in Beijing according to Manning criteria was 7.26%, in contrast to Rome criteria - 0.82%. Higher prevalence rate of IBS in the city (10.50%) than in rural areas (6.14%) (P < 0.001) was noticed. Male to female ratio was 1:1.15 with majority of IBS fell in age 18 - 40 (51.6%), and among intellectuals. Our study indicated that history of dysentery (OR = 3.00), exposure to coldness (OR = 1.55), ingestion of cold food and raw materials (OR = 1.24) might serve as the most important risk factors (P < 0.001). Patients with IBS seemed to have a higher tendency of abnormal personalities. CONCLUSION: IBS is a common disorder in Beijing which deserves greater care.

Adolescent↗

PubMed2000

[Studies on three types of natural foci of tsutsugamushi disease in eastern part of China].

OBJECTIVE: In order to identify the types of natural foci of tsutsugamushi disease to provide basis for prevention, a series of studies were carried out in Fujian, Zhejiang and Jiangsu Provinces. METHODS: (1) Representative points for investigation in three Provinces were selected. (2) Data on geographical landscape and epidemiology were collected. (3) Field survey and experimental studies on rats and chigger mites in relation to the disease. RESULTS: Three representative types of natural foci of tsutsugamushi disease were demonstrated. They were (1) Coastal island type, mainly in Fujian with major reservoir host as Rattus losea and major vector mite as L. deliense; prevalent season: summer; type of Rt: Gilliam: (2) Inland mountain - forest type in Zhejiang with major reservoir host as R. confucianus and major vector miteas L. gaohuense; prevalent season: summer; type of Rt: Gilliam. (3) Inland plain - hills type in Jiangsu with major reservoir hosts: Apodemus agrarius, R. confucianus, R. norvegicus and Crocidura lasiura; major vector mite: L. scutellare; prevalent seasons: autumn and winter; type of Rt: Kawasaki. CONCLUSION: The types of Rt, reservoir hosts, vector chigger mites and epidemiological features of tsutsugamushi disease in Fujian, Zhejiang and Jiangsu Province were found different. Thus, the preventive measures should also be distinct from one another.

Animals↗

PubMed2000

Effects of ketamine on neuronal activity of the spinal dorsal horn in rats with unilateral hindpaw inflammation.

A total of 32 units were extracellularly recorded from the spinal dorsal horn of rats. Unitary discharges evoked by stimulation of A and C fiber in ipsilateral lateral and medial plantar nerve were increased after carrageenan injection to the plantar area. The evoked responses to both A and C fiber were significantly decreased or even disappeared after administration of ketamine. The windup phenomenon was observed in neurons located deeply in the dorsal horn following carrageenan injection and was significantly suppressed or abolished after ketamine administration. The results above show NMDA receptor appears to be involved in the increase of excitability and the development of windup phenomenon in the spinal cord dorsal horn associated with carrageenan induced inflammation.

Animals↗

PubMed2000

[Clinical observation on changes of fibroblast growth factor in burn wounds].

OBJECTIVE: To investigate the changes of fibroblast growth factor (FGF) in burn wounds. METHODS: The FGF expression in the center of wound granulation, the edge of wound, the healed part of wound, the normal skin of patients, and the heal course of second degree burn wounds were detected by immunohistochemical methods. RESULTS: The expression intensity of FGF was different in the different sites of third degree burn wounds. The highest contents of FGF was in the center granulation of burn wounds, the less was in the borderline of wound and healed skin, and the least was in the healed skin. FGF expression mainly concentrated in the middle layer of wound, and almost no FGF expression in normal skin. The most FGF expression was occurred at 14 days after injury in second degree of burn wound. CONCLUSION: The changes of FGF in wounds are closely related to the wound healing, and rational use of FGF can promote wound healing.

Adult↗

PubMed2000

[Study on the combined toxicity of aflatoxin B1 and deoxynivalenol].

The toxicity of aflatoxin B1(AFB1) and deoxynivalenol(DON) on the injury and repair of DNA was studied. Replicative DNA synthesis was used to detect the change of DNA synthesis in the primary rat hepatocytes at the S phase of cell cycle. The results showed that both AFB1 and DON could induce DNA synthesis in primary rat hepatocytes at the S phase of cell cycle, and an interaction between them was found. It suggested that AFB1 and DON produced marked effects on engendering tumor as genetoxic and nongenotoxic carcinogens complementarily.

Aflatoxin B1↗

PubMed2000

[The investigation of color selection of 4340 cases of ceramic restorations].

OBJECTIVE: To find color coordinates of Vita color tabs compare with Chinese natural teeth and summarize the skills of color matching. METHODS: We studied 15,836 ceramic restorations of 4340 cases from 138 clinics in 18 provinces throughout China and compared their shade with that of the adjacent natural teeth using the Vita shade guide which has 16 standard tooth colors. Statistical analyses was made by comparing aptness of Chinese teeth with Vita shade. RESULTS: We found that 64.47% of the restorations were matched by Vita A, 15.85% were matched by Vita B, and 19.68% were matched by Vita C and D. The arrangement of Vita 16 colors by using frequency was A2, A3, B2, A1, A3.5, C1, D2, D3, C2, B3, C3, B1, A4, D4, B4 and C4. The first five color matching tabs used most frequently covered 73.85% of the total, while the last four colors only covered 3.07%. It seemed that Vita color tabs could not match well with Chinese teeth. We found that the shade of natural teeth was closely related to sex. But there were no significant difference between tooth color and different areas. CONCLUSION: Tooth color is closely related to sex. The color of ceramic crowns in men are darker than that in women. We have evidences that there are clear differences in color distribution between Chinese natural teeth and Vita shade guide.

China↗

PubMed2000

[Study on the rule of solvent strength in reversed-phase liquid chromatography].

Based on the physical meanings of Z (total moles of the released solvent at the contact region between solute and stationary phase), and j(the slope of the linear plot of lg I versus Z, a constant relating to the affinity of organic solvent to the stationary phase) of stoichiometric displacement model for retention (SDM-R) of solute in liquid chromatography(LC), both Z and j could be employed to characterize solvents, therefore, Z value only can be used as a characterization parameter for fixed solute and stationary phase. However, the parameter j is independent of solutes. As long as phase is given, j can be employed as a new characterization parameter of organic solvent strength in LC. With the homologues of methanol, ethanol and n-propanol as organic solvents in mobile phase and n-alkylalcohols as solutes, both the SDM-R and Snyder's empirical equation were tested, and compared with the corresponding parameters obtained from Snyder's empirical equation. With S [the slope of the linear plot of lg k' (k' is capacity factor) vs psi(volume fraction of organic solvent in mobile phase)] and lg kw0(the intercept of this plot), it was found that the two linear plots with the SDM-R, lg k' vs the composition of mobile phase and lg I vs Z were better than the corresponding plots with Snyder's empirical equation. The results indicate that Z, lg I and j decrease with the increase in the molecular size of the organic solvent of the homologue. This fact indicates that the solvent strength in LC depends on the size of solvent molecules. And the greater the solvent molecules, the stronger the solvent strength is. Furthermore the solvent strength was found to follow homologous rule. The j value may become a new parameter for the characterization of organic solvent strength in LC.

Chemical Phenomena↗