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Biomedical subjects

P Dai

Publications and source records attributed to P Dai.

At least 37 records · Page 2Linked to original sources
PubMed1999

Computer-aided three-dimensional reconstruction and measurement of the optic canal and intracanalicular structures.

OBJECTIVE: To reconstruct the human optic canal and its inner structures and to provide detailed knowledge of this region for optic nerve decompression. METHODS: Six optic canals and their inner structures were reconstructed using a computer-aided three-dimensional reconstruction system. Quantitative measurement of the canal wall thickness, bony canal transverse area, optic nerve transverse area, dural sheath transverse area, subarachnoid space transverse area, and subarachnoid space volume was done using the computer morphometric analysis system. The detailed spatial relationship among intracanalicular structures was also carefully identified on the three-dimensional models. RESULTS: The thinnest portion of the canal was the middle part of the medial wall (0.45 +/- 0.14 mm) and the narrowest space was in the middle part of the optic canal (the transverse area was 18.21 +/- 1.20 mm2). The volume of subarachnoid space that can be considered the compensatory space for distention incurred by the hemorrhage, optic nerve edema, or hematoma was 21.16 +/- 4.31 mm3. At the cranial opening, the middle part, and the orbital opening, its transverse area was 4.45 +/- 0.46 mm2, 2.68 +/- 0.54 mm2, and 1.23 +/- 0.34 mm2 respectively. CONCLUSIONS: Because the compensatory space was limited, even a tiny amount of blood or swelling of the nerve may cause optic nerve compression. Because the compensatory space for distention gradually decreases from cranial end to orbital end, the middle part and the anterior part of the optic canal and dural sheath are critical in optic nerve decompression.

Adult↗
PubMed1999

[Screening for mitochondrial 1555(G) mutation in patients with aminoglycoside antibiotic-induced deafness].

OBJECTIVE: To identify the incidence of the 1555(G) mutation in pedigrees and sporadic patients with aminoglycoside antibiotic- induced deafness so as, to privide the theoretical evidence for establishing the method of diagnosis of this disease. METHODS: Blood samples were obtained from two pedigrees and seven sporadic patients with aminoglycoside antibiotic-induced deafness, and five mothers of the sporadic patients. DNA was extracted from the isolated leukocytes. The mitochondrial DNA fragments were amplified by PCR; 1555(G) mutation was detected by Alw26 I restriction endonuclease digestion. RESULTS: Fourteen individuals from two pedigrees carried homoplasmic 1555(G) mutation. Seven sporadic patients and the five mothers did not have 1555(G) mutation. CONCLUSION: The incidence of the 1555(G) mutation in pedigrees with aminoglycoside antibiotic-induced deafness is fairly high, while in sporadic patients is low. Screening for mitochondrial 1555(G) mutation is of potential value to clinical use.

Adolescent↗
PubMed1999

[Computer-aided 3-D reconstruction and measurement of optic canal and intracanalicular structures].

OBJECTIVE: To reconstruct the human optic canal and its inner structures, and to provide knowledge of this region in detail for optic nerve decompression and further understanding on the pathologic mechanisms of indirect optic nerve injury. METHODS: 6 optic canals and its inner structures were reconstructed by using a computer-aided 3-dimensional (3-D) reconstruction system. Quantitative measurement for the canal wall thickness, bony canal transverse area, optic nerve transverse area, dual sheath transverse area, subarachnoid space transverse area, and subarachnoid space volume were done by means of the computer morphometric analysis system. The detailed spatial relations among intracanalicular structures were also carefully identified on the 3-D models. RESULTS: The thinnest portion of the canal was the middle part of the medial wall (0.45 +/- 0.35)mm, and the narrowest space was in the middle part of the optic canal [the transverse area was (18.21 +/- 2.50) mm(2)]. The volume of subarachnoid space which can be considered the compensatory space for distention incurred by the hemorrhage, optic nerve edema, or hematoma was (21.16 +/- 4.31) mm(3). At the cranial opening, the middle part and orbital opening, its transverse area was (4.45 +/- 1.12) mm(2), (2.68 +/- 1.32) mm(2), (1.23 +/- 0.83) mm(2), respectively. CONCLUSIONS: In the middle part, the restraining of the bony canal on injured nerve may be the most powerful. Since the compensatory space was limited, even a tiny amount of blood or swelling of the nerve may cause optic compression. Because the compensatory space for distention gradually decreases from cranial end to orbital end, the middle part and the anterior part of the optic canal and dural sheath are critical in optic nerve decompression.

Humans↗
PubMed1998

CBP alleviates the intramolecular inhibition of ATF-2 function.

The transcription factor ATF-2 (also called CRE-BP1), whose DNA-binding domain consists of a basic amino acid cluster and a leucine zipper (b-ZIP) region, binds to the cAMP response element as a homodimer or as a heterodimer with c-Jun. The amino-terminal region of ATF-2 containing the transcriptional activation domain is phosphorylated by stress-activated kinases, which leads to activation of ATF-2. We report here that CBP, which was originally identified as a co-activator of CREB, directly binds to the b-ZIP region of ATF-2 via a Cys/His-rich region termed C/H2, and potentiates trans-activation by ATF-2. The b-ZIP region of ATF-2 was previously shown to interact with the amino-terminal region intramolecularly and to inhibit trans-activating capacity. The binding of CBP to the b-ZIP region abrogates this intramolecular interaction. The adenovirus 13S E1A protein which binds to the b-ZIP region of ATF-2 also inhibited this intramolecular interaction, suggesting that both CBP and 13S E1A share a similar function as positive regulators of ATF-2. We found that the b-ZIP regions of c-Jun and CREB also interact with the C/H2 domain of CBP, suggesting that CBP acts as a regulator for a group of b-ZIP-containing proteins. These results shed light on a novel aspect of CBP function as a regulator for a group of b-ZIP-containing proteins.

Activating Transcription Factor 2↗
PubMed1998

A depsipeptide fungal metabolite inhibitor of cholesteryl ester transfer protein.

The organic extract of the fermentation broth of a fungus was found to contain a depsipeptide SCH 58149 (1), containing three amino acids and a beta-hydroxy acid, by spectroscopic studies. The amino acids were phenyl alanine, alanine and leucine and the beta-hydroxy acid is 3-hydroxy-4-methyl octanoic acid. SCH 58149 exhibited weak activity against cholesterol ester transfer protein (CETP) with an IC50 of 50 microM.

Acremonium↗
PubMed1998

Differential transcriptional regulation of the human squalene synthase gene by sterol regulatory element-binding proteins (SREBP) 1a and 2 and involvement of 5' DNA sequence elements in the regulation.

Transcription of the human squalene synthase (HSS) gene is regulated by variations in the level of cellular cholesterol. Three regulatory elements in the HSS promoter region are known to be involved in the regulation: 1) a modified sterol regulatory element (SRE) 1 (HSS-SRE-1), 2) an inverted SRE-3 (Inv-SRE-3), 3) an inverted Y box (Inv-Y-Box). We report here the regulatory role of distinct cis-elements in the HSS promoter by using mutants of an HSS-luciferase promoter reporter. The activity of a wild-type promoter reporter transiently transfected into HepG-2 cells is increased by sterol depletion of the cells or by coexpression of mature forms of the SRE-binding proteins (SREBP) 1a and SREBP-2. Differential activation by SREBP-1a and SREBP-2 of the reporter gene mutated at various regions of the promoter is observed. Mutation of either the HSS-SRE-1 or the Inv-SRE-3 sequence diminished the activation by SREBP-1a and by sterol depletion but did not affect the activation by SREBP-2. Simultaneous mutations of both of these sequences almost completely abolished activation of the promoter by SREBP-1a or by sterol depletion, but activation by SREBP-2 was retained at 70%. Mutation of the Inv-Y-Box sequence element decreased the activity of the promoter by 50% or more, and if mutated together with both SREs, the activation was almost completely abolished. Mutation of any single GC box of the two located at -40 to -57 did not affect activity, whereas simultaneous mutation of the two decreased activation by SREBP-2 by 60%, by lipid depletion by 20%, and had no effect on the activation by SREBP-1a. A Y box motif at -159 to -166 and an SRE-like sequence element (SRE-1(8/10)) at position -101 to -108 are also involved in the sterol regulation. These results indicate that the complex sterol-mediated transcriptional regulation of the HSS gene is due to the presence of multiple copies of diverse cis elements in the HSS promoter. The differential activation of the HSS promoter may point to specific role of the SREBPs in cholesterogenesis.

CCAAT-Enhancer-Binding Proteins↗
PubMed1998

[Blood supply reestablishment of avascular necrosis of femoral head with digital subtraction angiography].

OBJECTIVE: To use digital subtraction angiography (DSA) to evaluate blood supply reestablishment after the treatment of the avascular necrosis of femoral head (ANFH) by using the vascularized iliac periosteum with deep iliac circumflex artery (DICA) and vein pedicle. METHODS: Seldinger method was used to puncture femoral artery interpate of 20 patients with pre and postoperative ANFH. 6.5 F Cobrn conduct was optionally used and put directly into DICA and then contrast medium, was injected for observation of blood vessel. RESULTS: Before operation, the position of DICA was found constant, 3 to 7 branches termity among the crest part of iliac bone. Three weekes after operation, DICA was found wider than that before operation, but the blood flow speed remained almost the same and its termity was distributed evenly inside the femoral head and looked like a bird's net. Three months after operation, the blood vessel was still wider, but blood flowed faster and its termity changed roundish, and the bird's net changed greatly and capillaries reached the subchoronal zone of femoral head. CONCLUSION: Blood flow was well reestablished after the treatment of ANFH by DSA. It can be easily checked with less damage, large liability, and clear picture.

Adult↗
PubMed1998

[Extraction, amplification, recombination and sequencing of the mitochondrial DNA from celloidin embedded human temporal bone sections].

OBJECTIVE: To establish an analytical method of DNA extracted from human celloidin-embedded temporal bone sections by molecular biologic technique. METHODS: Polymerase chain reaction (PCR) with different primers, special amplification methods or coorperated with enzyme restricted reactions was adapted to detect several types of genetic mutations from 9 human celloidin-embedded temporal bone sections. The pGEM-T vector was used for the recombination and cloning of the amplified DNA fragment. RESULTS: The 135 bp fragments of normal mtDNA were detected from all of the 9 cases. The 316bp fragment related to mtDNA 4977bp deletion was also detected in two cases who suffered from presbycusis before death by the nested PCR. The result of sequencing confirmed the accuracy of PCR. CONCLUSION: The application of molecular biologic techniques in temporal bone research is important in improving the quality and value of retrospective study of ear diseases and has resulted in findings of the relevant mutant or pathogenetic genes in the ear diseases such as presbycusis, ototoxic deafness, otosclerosis and viral infections of the ear.

Adolescent↗
PubMed1997

Drosophila CBP is a co-activator of cubitus interruptus in hedgehog signalling.

The transcription factor CBP, originally identified as a coactivator for CREB, enhances transcription mediated by many other transcription factors. Mutations in the human CBP gene are associated with Rubinstein-Taybi syndrome, a haploinsufficiency disorder characterized by abnormal pattern formation, but the mechanism by which decreased CBP levels affect pattern formation is unclear. The hedgehog (hh) signalling pathway is an important determinant of pattern formation. cubitus interruptus (ci), a component in hh signalling, encodes a transcription factor homologous to the Gli family of proteins and is required for induction of the hh-dependent expression of patched (ptc), decapentaplegic (dpp) and wingless (wg). Haploinsufficiency for the ci-related transcription factor Gli3 causes phenotypic changes in mice (known as 'extra-toes) and humans (Greig's cephalopolysyndactyly syndrome) that have similarities to Rubinstein-Taybi syndrome. Here we show that Drosophila CBP (dCBP) functions as a coactivator of Ci, suggesting that the dCBP-Ci interaction may shed light on the contribution of CBP to pattern formation in mammals.

Animals↗
PubMed1997

Neurokinin receptor inhibitors: fermentation, isolation, physico-chemical properties, structure and biological activity.

Seven neurokinin (NK) receptor inhibitors SCH 60059 (1), SCH 60065 (2), SCH 64879 (3), SCH 60061 (4), SCH 60063 (5), SCH 60057 (7), and SCH 64878 (9) and two uncharacterized components 6 and 8, were isolated from the fermentation broth of a fungus taxonomically classified as an Acremonium sp. These compounds were isolated from the fermentation broth by ethyl acetate extraction. Purification and separation of the individual compounds were achieved by NK1 and NK2 assay-guided fractionation using gel filtration, reverse phase chromatography and HPLC. The NK active compounds were identified to be a family of polyhydroxy isoprenoid derivatives, including glycosylated members, by spectroscopic and degradation studies. Compounds 1 approximately 5 and 7 contain nine isoprene units connected in head to tail fashion and compound 9 contains fifteen isoprene units connected in a similar manner. All these compounds showed dual inhibition in NK1 and NK2 assays with IC50 values ranging from 2.5 approximately 11 microM in the NK1 assay and 6.8 approximately 16 microM in the NK2 assay.

Acremonium↗
PubMed1997

[3-D morphological study of the temporal bone].

OBJECTIVE: To establish the 3-D(three-dimensional) morphological study of the temporal bone by means of computer graphic techniques. METHODS: The serial sections of the temporal bone were processed by the technique of computer-aided 3-D reconstruction. The 3-D images of the multi-structures in the temporal bone were displayed on the monitor. The 3-D parameters of these structures were measured by a special software. The stereo-images of the structures in the temporal bone were obtained by stereoscopy and stereo-pairs. RESULTS: Most structures of the temporal bone were reconstructed in 37 instances for the different purpose of study. Each set of the stereo-pair corresponding to the structures in the temporal bones and many 3-D parameters were obtained. The complex spatial relationship among the reconstructed structures such as the facial nerve, endolymphatic sac, posterior tympanum and posterior ampullary nerve was revealed and the mechanic model of the ossicular chain was set up. According to these results, the surgical approach of the posterior ampullary nerve transection was designed and simulated on the graphic computer. CONCLUSION: The technique of computer-aided 3-D reconstruction provides a new tool for the study of the temporal bone. It is also helpful for the designs and simulations of the surgical approaches. The results of this study contribute to developmout of a new branch of pathology of the temporal bone and a primary 3-D morphological study of the temporal bone.

Ear, Middle↗
PubMed1996

CBP as a transcriptional coactivator of c-Myb.

CBP (CREB-binding protein) is a transcriptional coactivator of CREB (cAMP response element-binding) protein, which is directly phosphorylated by PKA (cAMP-dependent protein kinase A). CBP interacts with the activated phosphorylated form of CREB but not with the nonphosphorylated form. We report here that CBP is also a coactivator of the c-myb proto-oncogene product (c-Myb), which is a sequence-specific transcriptional activator. CBP directly binds to the region containing the transcriptional activation domain of c-Myb in a phosphorylation-independent manner in vitro. The domain of CBP that touches c-Myb is also required for binding to CREB. A c-Myb/CBP complex in vivo was demonstrated by a yeast two-hybrid assay. CBP stimulates the c-Myb-dependent transcriptional activation. Conversely, the expression of antisense RNA of CBP represses c-Myb-induced transcriptional activation. In addition, adenovirus EIA, which binds to CBP, inhibits c-Myb-induced transcriptional activation. Our data thus identify CBP as a coactivator of c-Myb. These results suggest that CBP functions as a coactivator for more transcriptional activators than were thought previously.

Adenovirus E1A Proteins↗