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Biomedical subjects

L Han

Publications and source records attributed to L Han.

At least 91 records · Page 5Linked to original sources
PubMed1998

[The clinical meaning and determination of the superoxid dismutase activity and malondialehyde content in the serum of the patients suffering from chronic tonsillitis].

The activity of SOD and MDA content in the serum of patients suffering from chronic tonsillitis were determined one day before operation and one week after of operation. It was found that the activity of T-SOD Mn-SOD and CuZn-SOD were decreased in the serum of patients with chronic tonsillitis than that in the normal control group with statistical significance (P < 0.01). T-SOD activity was increased and MDA content was decreased significantly after operation than the time before operation (P < 0.001, P < 0.01). This study indicates that tonsil excision could decrease MDA content and increased SOD activity for the chronic tonsillitis patient.

Adolescent↗
PubMed1998

[Clinical and experimental study on treatment of acute cerebral infarction with Acanthopanax Injection].

OBJECTIVE: To evaluate the effect of Radix Acanthopanacis Senticosi in treating acute cerebral infarction and its mechanism. METHODS: Clinical study using single-blind, control trial, in which 60-80 ml of Acanthopanax Injection (AI) added to 500 ml of 0.9% normal saline was given by intravenous drip once a day for 14 days in the AI group(34 patients), while 500 ml of dextra-40 was given by the same way in the control group(26 patients). In experimental study, rabbit model of acute incomplete cerebral ischemia was made by ligation of bilateral common carotid artery. 10 ml of AI were given once daily intravenously for 7 days to the AI group and 10 ml of normal saline was given to the control group in the same way. Clinical effects (in clinical study) and effect of AI on cerebral oxygen free radicals (OFR), superoxide dismutase (SOD), and serum concentration of ACTH and cortisone were observed (in experimental study). RESULTS: Clinical study showed that the total effective rate of AI group (86%) was higher than that of the control group (50%) while nervous functional deficit score was lower in AI group (9.96 +/- 4.66) than that in the control group (13.56 +/- 1.84) significantly. Experimental study showed that the cerebral level of OFR decreased while SOD increased and serum concentration of ACTH and cortisone decreased after treatment in AI group. CONCLUSIONS: AI was effective in treating acute cerebral infarction, the mechanism is probably by ameliorating peroxidation in brain and improving hypothalamic-pituitary-adrenocortical axis function.

Adrenocorticotropic Hormone↗
PubMed1998

[Effects of whole-body vibration on human tracking performance and visual-motor reaction].

Dual task test (light target tracking and visual-motor reaction of visual oddball mode) and pursuit aiming test were done in 17 male healthy subjects after 30min exposure to whole-body vibrations of 20 Hz 0.15 gz or 20 Hz 0.3 gz. Mean accuracy rate of visual-motor reaction and target stimulus reaction accuracy rate after 0.3 gz vibration were significantly lower than those of control group (P < 0.05), while after 0.15 gz vibration, the changes were not significant. Comparing with control group, the total number of right and wrong pointing, pointing speed in pursuit aiming test were significantly lower (P < 0.05) after vibration. However, light target tracking error, mean reaction time of visual-motor reaction and pointing accuracy rate of pursuit aiming test had no significant change after exposure to any kind of the vibrations. It may be concluded that some kinds of effect on human tracking performance and visual-motor reaction were observed after exposure to whole-body vibration.

Adult↗
PubMed1998

[Effect of noise on human mental rotation performance].

To investigate the effect of moderate level low frequency noise on human mental rotation performance, letter rotation and compass orientation tests were performed in 24 healthy young male subjects during 2 h exposure to 85-95dB (A), it was found that during 120 min exposure to noise of 85dB (A), the mean reaction time increased (P<0.05), performance of reaction time and total performance decreased (P<0.01) significantly as compared with control in letter rotation test, meanwhile, performance of reaction time and total performance at 120 min exposure were significantly higher than that at 30 min (P<0.05). During 120 min exposure to noise of 95dB (A), the mean reaction time increased (P<0.01), the performance of reaction time and total performance decreased (P<0.01) significantly as compared with control in compass orientation test, meanwhile, performance of reaction time at 120 min were significantly higher than that at 30 min(P<0.05). The results show that exposures to 85 dB(A) and 95 dB(A) noise for 2 h have certain effect on the performance of human mental rotation and may affect performance of complex tasks with a higher workload.

Adolescent↗
PubMed1998

Effects of acute moderate hypoxia on human performance of arithmetic.

To observe the effects of acute moderate hypoxia on human performance of arithmetic, the continuous calculation test, addition-subtraction test and mental arithmetic tests were made in 16 health young male subjects during exposure to altitude of 300 m (control), 3600 m, 4400 m and 5000 m by mean of hypobaric cabin simulation. Error rate of the continuous calculation test and reaction time of addition-subtraction test increased significantly and performance decreased significantly (P < 0.05) after exposure to 3600 m for 1 h. Reaction time, total number and performance of all tests decreased significantly (P < 0.05) during exposure to 4400 m. Performance of all tests decreased (P < 0.01) after exposure to 5000 m for 30 min.

Adolescent↗
PubMed1998

[The indication and mode of surgery for the treatment of patients with severe acute pancreatitis].

OBJECTIVE: To study the indication and mode of surgical management in patients with severe acute pancreatitis (SAP). METHOD: 41 patients with SAP were grouped for conservative treatment or surgical. The main procedures of surgical management were pancreatic debridement, peripancreatic and coeliac drainage, combined with peripancreatic instillation and suction alternatively. RESULT: Conservative treatment was adopted in 22 patients (16 patients in grade I, 6 in grade II), among them 19 recovered, and 3 of grade II died. 19 patients underwent surgical treatment including 7 in grade I, 12 in grade II). 15 patients were cured, 4 patients of grade II died. CONCLUSION: Timely operation is necessary for the patients with infection and complications. Surgical intervention is recommended for patients older than 60 years old. Surgery should be less traumatic, simple and prompt. Surgical or conservative treatment are chosen according to the patients' conditions. The cure rate of SAP can be improved.

Adult↗
PubMed1998

[An analysis of treatment of intravitreal lens fragments following phacoemulsification].

OBJECTIVE: To observe and evaluate the outcome of vitrectomy in the treatment of dropped lens fragments. METHOD: Retrospectively the authors reviewed and analyzed 58 cases of dropped lens fragments that were treated with vitrectomy from October 1992 to October 1995 in Royal Victoria Eye and Ear Hospital, Melbourne, Australia and followed for at least 3 months. RESULTS: At the last follow-up, the remained complications were cystoid macular edema in three cases (5.2%), retinal detachment in two cases (3.4%) and hypotony in one case (1.7%). Other complications were all resolved. The final vision was significantly better than that before vitrectomy. There were 38 eyes (65.5%) with final visual acuities of 0.5 or better, and only 6 eyes (6.9%) with < 0.05. CONCLUSION: Once the lens fragments are dropped into the vitreous during phacoemulsification, the ocular anterior segment should be properly managed, if possible intraocular lens is inserted, and then vitrectomy should be performed as soon as possible. Generally, with the above method good therapeutic effects can be obtained.

Aged↗
PubMed1998

[Comparing Swerita daridi with Swertia mileencis on pharmacologic action].

The article compared Swertia daridi with Swertia mileencis about chemical composition and pharmacological action. The study showed two species drug's bitter taste chemical composition and pharmacological action are approximately equal. It can be tried to replace Swertia daridi with Swertia mileencis.

Animals↗
PubMed1997

Fine structure of the murine leptin receptor gene: splice site suppression is required to form two alternatively spliced transcripts.

The fine structure of the murine leptin receptor gene (Lepr) is described. Duplicated ligand binding domains (conserved among cytokine receptors) are found in eight exons (coding exons 3 to 6 and 8 to 11). Thus, it is possible that a single leptin receptor molecule could have two functional ligand binding domains. The transmembrane region of Lepr is in coding exon 16 while the juxtamembrane JAK docking site is in coding exon 17. For all membrane-bound forms, the transcript must include 17 invariant exons and 1 alternatively spliced 3' terminal exon. The transcript encoding the soluble receptor (Re) includes 14 coding exons and an alternatively spliced 3' terminal exon. We have identified two splice variants (Rc and Re) for which there are no intervening sequences between the two final exons. This unusual juxtaposition of exons requires that splice donor sites at the 5' end of the respective terminal exons be ignored in the production of these splice variants. We suggest that splice site suppression is responsible for the formation of two of the alternatively spliced forms of the mouse Lepr gene. The juxtaposition of two coding exons separated by a consensus splice donor sequence is the structural substrate for this mode of alternative splicing. We present evidence that the Rc form is expressed in human tissues while the Re form, the soluble receptor, is not expressed.

Alternative Splicing↗
PubMed1997

Protein binding and signaling properties of RIN1 suggest a unique effector function.

Human RIN1 was first characterized as a RAS binding protein based on the properties of its carboxyl-terminal domain. We now show that full-length RIN1 interacts with activated RAS in mammalian cells and defines a minimum region of 434 aa required for efficient RAS binding. RIN1 interacts with the "effector domain" of RAS and employs some RAS determinants that are common to, and others that are distinct from, those required for the binding of RAF1, a known RAS effector. The same domain of RIN1 that binds RAS also interacts with 14-3-3 proteins, extending the similarity between RIN1 and other RAS effectors. When expressed in mammalian cells, the RAS binding domain of RIN1 can act as a dominant negative signal transduction blocker. The amino-terminal domain of RIN1 contains a proline-rich sequence similar to consensus Src homology 3 (SH3) binding regions. This RIN1 sequence shows preferential binding to the ABL-SH3 domain in vitro. Moreover, the amino-terminal domain of RIN1 directly associates with, and is tyrosine phosphorylated by, c-ABL. In addition, RIN1 encodes a functional SH2 domain that has the potential to activate downstream signals. These data suggest that RIN1 is able to mediate multiple signals. A differential pattern of expression and alternate splicing indicate several levels of RIN1 regulation.

3T3 Cells↗
PubMed1997

The packaging capacity of adeno-associated virus (AAV) and the potential for wild-type-plus AAV gene therapy vectors.

Because of its ability to integrate chromosomally and its non-pathogenic nature, adeno-associated virus (AAV) has significant potential as a human gene therapy vector. Here we investigate the maximum amount of DNA which can be inserted into the AAV genome and still allow efficient packaging into an infectious virus particle. Altered wild-type AAV genomes were constructed with inserts, which increased in size by 100 bp, ligated at map unit 96. These large wild-type-plus genomes were able to replicate and produce infectious virus, at levels slightly reduced but comparable to normal sized wild type, until the insert size reached 1 kb. These data indicate that the maximum effective packaging capacity of AAV is approximately 900 bp larger than wild type, or 119%. Furthermore, it is demonstrated that these large AAV genomes are able to latently infect cells by chromosomal integration as does wild-type AAV. These data suggest that therapy vectors carrying a foreign gene of 900 bp or less can be generated from AAV, by ligation into non-essential locations, and result in a recombinant AAV virus with a fully wild-type phenotype. Such wild-type-plus AAV vectors will have both advantages and disadvantages over defective recombinant AAV virus - the most important advantages being the ease in which high titers of infectious virus can be generated and the ability to specifically integrate within chromosome 19. Once the concern subsides over the presence of wild-type AAV in clinical applications, wild-type AAV vectors may find specific application niches for use in human gene therapy.

Cells, Cultured↗
PubMed1997

Regulation of the oncogenic activity of BCR-ABL by a tightly bound substrate protein RIN1.

RIN1 was originally identified by its ability to physically bind to and interfere with activated Ras in yeast. Paradoxically, RIN1 potentiates the oncogenic activity of the BCR-ABL tyrosine kinase in hematopoietic cells and dramatically accelerates BCR-ABL-induced leukemias in mice. RIN1 rescues BCR-ABL mutants for transformation in a manner distinguishable from the cell cycle regulators c-Myc and cyclin D1 and the Ras connector Shc. These biological effects require tyrosine phosphorylation of RIN1 and binding of RIN1 to the Abl-SH2 and SH3 domains. RIN1 is tyrosine phosphorylated and is associated with BCR-ABL in human and murine leukemic cells. RIN1 exemplifies a new class of effector molecules dependent on the concerted action of the SH3, SH2, and catalytic domains of a cytoplasmic tyrosine kinase.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Human papillomavirus is more prevalent in first trimester spontaneously aborted products of conception compared to elective specimens.

In this study the possible role of human papillomaviruses (HPV) in spontaneous abortions is addressed by assaying for HPV DNA in first trimester spontaneous and electively aborted products of conception materials enriched for chorionic villi. The presence of HPVs was measured by polymerase chain reaction (PCR) amplification and DNA dot blot hybridization using an internal probe. The "broad spectrum" HPV primers were directed to amplify E6/E7 junction sequences, while the probe was of an HPV-16 sequence with significant homology to HPV-6/11. The quantity and quality of isolated DNA was also analyzed and compared by observing the PCR amplification of a cellular sequence from the human beta-globin gene. Fifteen of the 25 spontaneous samples (60%) were found to be positive for HPV E6/E7 sequences. In comparison, only 3 of the 15 elective samples (20%) were positive. This is the first study of HPV in fetal materials to incorporate material from elective abortions as a control group. Although confounding contamination from the cervix and vagina can't be ruled out, these data are significant and strongly suggest that HPVs are elevated in spontaneously aborted products of conception. Furthermore, these results suggest the possibility that HPVs may be etiologic agents of at least some spontaneous abortions.

Abortion, Induced↗
PubMed1997

Nanophthalmos with longstanding choroidal effusion and serous retinal detachment.

PURPOSE: To report a typical case of nanophthalmos with uveal effusion and local serous retinal detachment followed for 1 year. METHODS: Clinical ocular examinations included vision, refraction, corneal diameter, anterior chamber depth, intraocular pressure, fundoscopy, A/B scan ultrasonography and gonioscopy. RESULTS: Both eyes were hypermetropic with small corneas and shallow anterior chambers. Decreased axial length and thickened sclera were also found. There were peripheral choroidal effusions and local serous retinal detachments as well. The patient declined any surgery that was offered. No significant change in either eye was found after 1 year follow-up. CONCLUSION: This case illustrates that the progress of choroidal effusion and retinal detachment in nanophthalmos may be very slow and even non-progressive for at least 1 year. In these cases sclerectomy and or sclerotomy may be delayed without undue immediate risk to the vision.

Anterior Chamber↗
PubMed1997

In vivo and in vitro effects of thiolactomycin on fatty acid biosynthesis in Streptomyces collinus.

A stable-isotope assay was used to analyze the effectiveness of various perdeuterated short-chain acyl coenzyme A (acyl-CoA) compounds as starter units for straight- and branched-chain fatty acid biosynthesis in cell extracts of Streptomyces collinus. In these extracts perdeuterated isobutyryl-CoA was converted to isopalmitate (a branched-chain fatty acid), while butyryl-CoA was converted to palmitate (a straight-chain fatty acid). These observations are consistent with previous in vivo analyses of fatty acid biosynthesis in S. collinus, which suggested that butyryl-CoA and isobutyryl-CoA function as starter units for palmitate and isopalmitate biosynthesis, respectively. Additionally, in vitro analysis demonstrated that acetyl-CoA can function as a starter unit for palmitate biosynthesis. Palmitate biosynthesis and isopalmitate biosynthesis in these cell extracts were both effectively inhibited by thiolactomycin, a known type II fatty acid synthase inhibitor. In vivo experiments demonstrated that concentrations of thiolactomycin ranging from 0.1 to 0.2 mg/ml produced both a dramatic decrease in the cellular levels of branched-chain fatty acids and a surprising three- to fivefold increase in the cellular levels of the straight-chain fatty acids palmitate and myristate. Additional in vivo incorporation studies with perdeuterated butyrate suggested that, in accord with the in vitro studies, the biosynthesis of the palmitate from butyryl-CoA decreases in the presence of thiolactomycin. In contrast, in vivo incorporation studies with perdeuterated acetate demonstrated that the biosynthesis of palmitate from acetyl-CoA increases in the presence of thiolactomycin. These observations clearly demonstrate that isobutyryl-CoA is a starter unit for isopalmitate biosynthesis and that either acetyl-CoA or butyryl-CoA can be a starter unit for palmitate biosynthesis in S. collinus. However, the pathway for palmitate biosynthesis from acetyl-CoA is less sensitive to thiolactomycin, and it is suggested that the basis for this difference is in the initiation step.

Acetic Acid↗
PubMed1997

A novel alternate anaplerotic pathway to the glyoxylate cycle in streptomycetes.

ccr encoding crotonyl coenzyme A (CoA) reductase (CCR), which catalyzes the conversion of crotonyl-CoA to butyryl-CoA in the presence of NADPH, was previously cloned from Streptomyces collinus. We now report that a complete open reading frame, designated meaA, is located downstream from ccr. The predicted gene product showed 35% identity with methylmalonyl-CoA mutases from various sources. In addition, the predicted amino acid sequences of S. collinus ccr and meaA exhibit strong similarity to that of adhA (43% identity), a putative alcohol dehydrogenase gene, and meaA (62% identity) of Methylobacterium extorquens, respectively. Both adhA and meaA are involved in the assimilation of C1 and C2 compounds in an unknown pathway in the isocitrate lyase (ICL)-negative Methylobacterium. We have demonstrated that S. collinus can grow with acetate as its sole carbon source even though there is no detectable ICL, suggesting that in this organism ccr and meaA may also be involved in a pathway for the assimilation of C2 compounds. Previous studies with streptomycetes provided a precedent for a pathway that initiates with the condensation of two acetyl-CoA molecules to form butyryl-CoA, which is then transformed to succinyl-CoA with two separate CoB12-mediated rearrangements and a series of oxidations. The biological functions of ccr and meaA in this process were investigated by gene disruption. A ccr-blocked mutant showed no detectable crotonyl-CoA reductase activity and, compared to the wild-type strain, exhibited dramatically reduced growth when acetate was the sole carbon source. An meaA-blocked mutant also exhibited reduced growth on acetate. However, both methylmalonyl-CoA mutase and isobutyryl-CoA mutase, which catalyze the two CoB12-dependent rearrangements in this proposed pathway, were shown to be present in the meaA-blocked mutant. These results suggested that both ccr and meaA are involved in a novel pathway for the growth of S. collinus when acetate is its sole carbon source.

Acetates↗