Biomedical subjects

Q Fan

Publications and source records attributed to Q Fan.

At least 55 records · Page 3Linked to original sources

PubMed1996

Sympathetic nerve trajectories to rat orbital targets: role of connective tissue pathways.

The trajectories of sympathetic nerves projecting to orbital targets were determined in adult rats with intact innervation and following acute sympathetic denervation, neonatal unilateral superior cervical ganglionectomy, or unilateral ganglionectomy on postnatal day 30. Sympathetic nerves were identified by using immunofluorescence for the noradrenergic transmitter enzyme dopamine beta-hydroxylase and by using catecholamine histofluorescence. In rats with intact innervation, sympathetic fibers travel to the orbit in association with the abducens, trochlear, and Vidian nerves. Within the retroorbital and retroocular connective tissue, the fibers redistribute to become associated with sensory-nerve branches of the trigeminal nerve, the orbital vasculature, and the periorbital sheath. Fibers reach their targets by traversing variable amounts of connective tissue of the periorbitum, the orbital septa, and the striated muscle epimysia. Following neonatal ganglionectomy, intracranial fibers of contralateral origin enter the orbit by traveling through connective tissue of the optic nerve meninges and lining the anterior lacerated foramen. These fibers travel independent of the trochlear, abducens, and Vidian nerves, but, otherwise, they use the same orbital pathways as those employed in the intact animal. In animals ganglionectomized on postnatal day 30, fibers enter the posterior portion of the orbit primarily via the optic foramen; they travel only short distances and end blindly in the periorbital sheath. These findings indicate that fascial structures are a major component of the pathways that guide sympathetic fibers to their appropriate targets both in normal development and during reinnervation following neonatal ganglionectomy. Because orbital connective tissues are termination sites of abortive fiber sprouting in older rats, developmental changes in the properties of these tissues may contribute to the absence of pathway formation in the mature animal.

Adrenergic Fibers↗

PubMed1996

Effect of physical constraints on the mechanisms of membrane fusion: bolaform lipid vesicles as model systems.

Bolaform lipid vesicles were used to study the effect of physical constraints on membrane fusion. In these vesicles the membrane is organized in a single monolayer, because of the presence of covalent bonds in its middle plane. Therefore, the formation of fusion intermediates is subject to higher energy barriers and greater geometrical constraints than is usual in bilayer membranes. Bolaform lipids were extracted from the thermophilic archaeon Sulfolobus solfataricus. These lipids can be divided into two classes, the monosubstituted molecules, in which one of the polar heads is glycerol, and the bisubstituted molecules, endowed with two complex polar heads. The fusion process in vesicles composed of different mixtures of monosubstituted/bisubstituted molecules was studied by means of fluorescence techniques. Ca2+ or poly(ethylene glycol) was employed as a fusogenic agent. We found that fusion of such constrained membranes is still possible, provided that molecules able to mediate a structural rearrangement of the membrane are present. This condition is fulfilled by monosubstituted molecules, which are able to partition the glycerol headgroup in the apolar moiety. In addition, the presence of traces (approximately 5%) of the monopolar compound diphytanylglycerol is an important factor for fusion to occur. On the contrary, vesicles formed by bisubstituted molecules are unable to fuse, irrespective of the fusogen employed.

Cell Membrane↗

PubMed1996

Psychological long-term effects of sterilization on anxiety and depression.

Two-thousand cases (500 women and 500 men with sterilization; 500 women and 500 men without sterilization) in two counties and two cities in Sichuan, China, were investigated between 15 September 1992 and 30 April 1993. Information was obtained about their age, parity, marriage, contraceptives, social behavior, and present psychological characteristics. CES-D, SAS, and E.P.Q. scales were used to assess the depressive symptomatology, anxiety, and personality of the subjects. The results revealed that sterilization psychologically affected the depressive symptoms and anxiety under the neutral personality. In addition, depressive symptoms and anxiety were related to the subjects' age, educational level, income, operative doctors' attitudes to sterilization acceptors, and subjects' understanding of the sterilization.

Adult↗

PubMed1996

Phototherapy of cancer and atheromatous plaque with texaphyrins.

Cancer and cardiovascular disease are the leading causes of death in the western world. Photodynamic therapy (PDT) has demonstrated activity in the treatment of superficial cancerous lesions and as an intraoperative adjunct during surgical debulking. Texaphyrins are pure, synthetic water-soluble macrocycles that localize in both cancerous lesions and atheromatous plaque. Lutetium texaphyrin (PCI-0123) is activated by tissue-penetrating far red light (720-760 nm). Patient diagnosis and treatment planning is possible via magnetic resonance imaging (MRI) with the paramagnetic gadolinium texaphyrin (PCI-0120) or via fluorescence imaging using the diamagnetic PCI-0123. In this study it is shown that texaphyrins localize selectively in cancer and atheromatous plaque. PDT with PCI-0123 is found to cause selective photodamage to the diseased tissue. Specifically, PCI-0123 acts to eradicate the SMT-F murine mammary tumors and diet-induced atheromatous plaque in rabbits.

Animals↗

PubMed1996

Imaging of human colon cancer xenograft with gadolinium-texaphyrin.

RATIONALE AND OBJECTIVES: The authors explore the efficacy of gadolinium (Gd)-texaphyrin (PCI-0101), an expanded porphyrin, as a contrast medium for magnetic resonance imaging of nude mice implanted with the human colon cancer xenograft LS174T. METHODS: Magnetic resonance images were obtained in six nude mice 7 to 8 days after implantation of LS174T cells in dorsal subcutaneous tissues. Spin-echo T1-weighted images were obtained at baseline and at 5, 15, and 60 minutes after injection of 10 or 20 mumols/kg of Gd-texaphyrin. Delayed images were obtained at 24 and 48 hours after injection. Region-of-interest measurements were taken of the tumors and of enhancing tumor rims at all time points. Percent enhancement was calculated and compared among the various time points. RESULTS: All tumors were enhanced after injection of Gd-texaphyrin. Heterogeneous patterns of enhancement were seen, with peak enhancement seen at the 15-minute time point; however, greater enhancement was seen at 48 hours than at 24 hours after Gd-texaphyrin intravenous injection. CONCLUSIONS: Gadolinium-texaphyrin may prove to be a useful contrast medium for magnetic resonance imaging of tumors.

Animals↗

PubMed1996

Experimental acute cerebral ischemia with reperfusion. Evaluation with gadolinium-texaphyrin.

RATIONALE AND OBJECTIVES: The authors explore the potential usefulness of the new contrast medium gadolinium (Gd)-texaphyrin (PCI-0101) in magnetic resonance imaging of experimental acute cerebral ischemia with reperfusion. METHODS: Four New Zealand white rabbits underwent 2 hours of transorbital occlusion of the left internal carotid, anterior, and middle cerebral arteries, followed by 2 hours of reperfusion with normal saline. Immediately thereafter, the rabbits were injected with 25 mumol/kg of 2 mmol/L Gd-texaphyrin and killed by barbiturate overdose. Postmortem T1- and T2-weighted coronal scans were performed at 1.5 Tesla and correlated with histopathologic findings. RESULTS: Postcontrast T1-weighted images showed high signal within extensive cortical and basal ganglia infarcts. Areas of high signal on T1-weighted images were less extensive than on T2-weighted images, and corresponded to only a portion of the region of neuronal damage seen histologically. Signal intensity of infarcted brain on postcontrast T1-weighted images was significantly greater than normal brain in the contralateral hemisphere (P < 0.0014). CONCLUSIONS: Experimental reperfused infarcts only 2 hours old demonstrate contrast enhancement with Gd-texaphyrin.

Acute Disease↗

PubMed1996

A robust sequential detection algorithm for cardiac arrhythmia classification.

In [1] qnd [2] Thakor et al. describe a sequential probability ratio test (SPRT) based on threshold crossing intervals (TCI) for the discrimination of ventricular fibrillation (VF) from ventricular tachycardia (VT). However, in applying their algorithm to data from the MIT-BIH malignant arrhythmia database, we observed some overlap in the distributions of TCI for VF and VT resulting in 16% overall error rate for the discrimination. In this communication, we describe a modified SPRT algorithm, using a new feature dubbed blanking variability (BV) as the basis for discrimination. Using the MIT-BIH database, the preliminary results showed that the proposed method decreases the overall error rate to 5%.

Algorithms↗

PubMed1996

Lutetium texaphyrin (PCI-0123): a near-infrared, water-soluble photosensitizer.

Lutetium texaphyrin, PCI-0123, is a pure, water-soluble photosensitizer with a large broad absorption band centered at 732 nm. The compound was tested for photodynamic therapy (PDT) effectiveness in a murine mammary cancer model. The texaphyrin macrocycle as illustrated by magnetic resonance imaging and 14C-radiolabeled texaphyrin studies was shown to be tumor selective; a tumor-to-muscle ratio of 10.55 was seen after 5 h. Lutetium texaphyrin, at a drug dose of 20 mumol/kg with irradiation 5 h postinjection at 150 J/cm2 and 150 mW/cm2, had significant efficacy (P < 0.0001) in treating neoplasms of moderate size (40 +/- 14 mm3) and also had significant efficacy (P < 0.0001) in treating larger neoplasms (147 +/- 68 mm3). The PDT efficacy was correlated with the time interval between PCI-0123 administration and light exposure. A 100% cure rate was achieved when photoirradiation took place 3 h postinjection compared to 50% for 5 h using 10 mumol/kg and 150 J/cm2 at 150 mW/cm2. The PDT efficacy was attributable to the selective uptake/retention of the texaphyrin photosensitizer in addition to the depth of light penetration achievable at the 732 nm laser irradiation.

Animals↗

PubMed1996

New telomere formation coupled with site-specific chromosome breakage in Tetrahymena thermophila.

Programmed chromosome breakage occurs in many ciliated protozoa and is accompanied by efficient new telomere formation. In this study, we have investigated the relationship between programmed chromosome breakage and telomere formation in Tetrahymena thermophila. Using specially constructed DNA clones containing the breakage signal Cbs in transformation studies, we have determined the locations of telomere addition around the breakage sites. They occur at variable positions, over 90% of which are within a small region (less than 30 bp) starting 4 bp from Cbs. This distribution is independent of the nucleotide sequence in the region or of the orientation of Cbs. In five of six cases determined, these sites occur at or before a T, and in the remaining case, the site occurs at or before a G. When sequences devoid of G or T are placed in this region, telomere addition still occurs within the region to maintain a similar distance relationship with Cbs. This efficient and healing process appears to be associated specifically with Cbs-directed breakage, since it does not occur when DNA ends are generated by restriction enzyme digestion. These results suggest a strong mechanistic link between chromosome breakage and telomere formation.

Amino Acid Sequence↗

PubMed1996

[Angiomatoid malignant fibrous histiocytoma].

By clinical, pathologic and immunohistochemical study on aniomatoid malignant fibrous histiocytoma, which is a relatively uncommon soft tissue tumor described by Enzinger in 1979, and often misdiagnosed, we are reporting 32 cases of this lesion. The distinctive histopathology were: (1) Cystic change filled with hemorrhagic fluid or blood, (2) surrounded by nests of fibroblastlike and histocyte-like cells and (3) intermingled with chronic inflammatory cells, (4) often surrounded by a fibrous pseudocapsule. Immunohistochemical staining done in 4 cases showed all to be positive in lysozyme, three positive in Mac 387 and CD 68. These results support their histiocytic origin. Follow-up information was available in 25 of 32 cases. All the 25 patients were alive, 4 with recurrence (16%), 1 with metastasis (4%). These results concur with the opinion that intrinsically, this is a low grade tumor.

Adolescent↗

PubMed1996

Surgical treatment of bone tumors in conjunction with microwave-induced hyperthermia and adjuvant immunotherapy. A preliminary report.

OBJECTIVE: To develop an alternative approach in conjunction with microwave-induced hyperthermia. PATIENTS AND METHODS: Thermotherapy with microwave intracorporeal irradiation was used to treat 73 patients with bone tumors. The series was composed of 58 patients with malignant tumors and 15 with benign tumors: most of tumors occurred about knee joints (53/73 = 72.6%). The surgical procedure included separating the tumor bearing segment from surrounding normal tissues with a safe margin, cooling the normal tissues including the neurovascular bundle and the intraarticular structures with a water circulation system, while heating the tumor with the antenna array of a microwave system and providing an adequate soft-tissue cover for the dead bone. Postoperatively, an immune therapy regimen was carried out regularly. The patients' immunologic functions were monitored by assay of the subpopulation of T cells, IL-2 and sIL-2 R (soluble IL-2 receptor). RESULTS: Follow-up varied from 3 to 38 months (mean 19 months). Excluding 3 patients with malignancy in the vertebrae treated for palliation, 70 were evaluated according to oncological and orthopedic criteria. Five patients had local recurrence and required amputation. The remaining 65 had excellent local control. In 6 of the 55 patients with malignancy of the extremities, lung metastasis occurred one to two years after surgery. The oncological results were similar to those obtained by other limb-saving procedures. Pathological fracture occurred at devitalized bone in 5 patients. In 72.5% of the patients (29 of 40 tumor-free cases followed more than one year), knee joints functioned well, being stable and painless with almost full range of motion. Single photon emission computered tomography (SPECT) for 16 patients revealed revascularization of the devitalized tumor bearing bone segment could accomplish in one year or more. The immune states were improved in various extends after thermotherapy plus immunotherapy in the majority of patients. CONCLUSION: These results show that the use of microwave hyperthermia and adjuvant immunotherapy in conjunction with the surgical treatment of bone tumors can be considered a definitive procedure, which is safe and well-tolerated. The oncological and orthopedic results are encouraging.

Adolescent↗

PubMed1996

[Application of the thoraco-umbilical flap for the repair of large infected wounds on the limb].

We have repaired large infected wounds on the limb in 18 cases using the thoraco-umbilical flap. Of them, 6 were island flaps and 12 were free flaps. The size of the flap ranged from 10 cm x 12 cm, to 10 cm x 40 cm. All flaps survived. The advantages of the flap were (1) rich blood supply providing good anti-infection property; (2) the muscle carried by the flap could be used to fill a bone cavity, aiding to cure osteomyelitis; (3) the flap could be made rather big and has long vascular pedicle that was flexible for transferring.

Adolescent↗

PubMed1995

Stability against temperature and external agents of vesicles composed of archael bolaform lipids and egg PC.

The bolaform lipid PLE extracted from the thermophilic archaeon Sulfolobus solfataricus and its mixtures with egg phosphatidyl-choline (egg PC) have been used to prepare sonicated vesicles. The leakage of entrapped calcein was continuously monitored by fluorescence dequenching. The half times of leakage have been used to compare vesicle stability under different conditions of temperature, lipid composition and presence of destabilizing agents like Ca2+ ions and poly(ethylene glycol) (PEG). It has been found that leakage is primarily modulated by the monopolar/bipolar lipid ratio. In particular, the half time of leakage for vesicles formed from a mixture of the polar lipid extract (PLE) and egg PC is characterized by a maximum at about 1:2 molar ratio. The free energy of mixing has been evaluated from pressure-area isotherms on monolayers at the air/water interface. The results indicate a non monotonous behaviour of the excess free energy of mixing as a function of the molar ratio and the occurrence of a minimum at a fixed molar ratio. The possible formation of a complex is discussed and compared with previous calorimetric measurements on similar compounds.

Calcium↗

PubMed1995

Meiosis-specific double-strand DNA breaks at the HIS4 recombination hot spot in the yeast Saccharomyces cerevisiae: control in cis and trans.

The region of Saccharomyces cerevisiae chromosome III located between the 5' end of the HIS4 gene and the 3' end of the adjacent BIK1 gene has a very high level of meiotic recombination. In wild-type strains, a meiosis-specific double-strand DNA break occurs in the hot spot region. This break is absent in strains in which the transcription factors Rap1p, Bas1p, and Bas2p cannot bind to the region upstream of HIS4. In strains with levels of recombination that are higher than those of the wild type, the break is found at elevated levels. The linear relationship between hot spot activity and the frequency of double-strand DNA breaks suggests that these lesions are responsible for initiating recombination at the HIS4 recombination hot spot.

Chromosome Aberrations↗

PubMed1995

[Amplification of proto-oncogenes C-myc, C-N-ras, C-Ki-ras, C-erbB2 in ovarian carcinoma].

OBJECTIVE: To observe the amplification rate of C-myc, C-N-ras, C-Ki-ras, C-erbB2 in human ovarian carcinoma. METHODS: Southern blot hybridization of DNA was employed, pathological diagnosis was made from fresh tissues. The beta-globin gene was used as an internal control. RESULTS: The amplification rate of C-myc, C-N-ras, C-Ki-ras and C-erbB2 in ovarian carcinoma was 50%, 44%, 31% and 25% respectively. The amplification rates of C-myc, C-erbB2 in stage III and IV were all significantly greater than that in stage I (P < 0.01). The amplification rate of C-N-ras in stage I was also significantly greater than that in stage III (P < 0.01). The amplification rate of C-Ki-ras in stage I was significantly greater than that in stage III or IV (P < 0.01). CONCLUSIONS: The amplification of C-Ki-ras and C-N-ras took place chiefly in cases of the early stages and in cases with good differentiation. The amplification of C-N-ras was also found in cases of advanced stages. The amplifications of C-myc and C-erbB2 were chiefly found in cases above stage III and in cases with poor differentiation, 83% of the patients who died were found to have amplifications of more than 2 proto-oncogenes, with the amplification of C-erbB2 involved in all of them.

Blotting, Southern↗

PubMed1995

A specific protein found in human senescent fibroblasts.

The limited potential for proliferation of human fibroblasts in culture represents cell level senescence. Aging is a programmed process under genetic control, and at certain stage of the life-span of animal cells, some genes start to express. Studying the biomarkers of senescent cells is important to understanding the basic mechanism of aging which may be relevant to the normal cell growth control and tumor biology. A protein with 72,000 Dalton molecular weight was detected by the hybridoma method in our laboratory. The protein shows specificity to senescent or presenescent cells of several cell lines, including WI-38, K.D., U2OS, etc.

Animals↗

PubMed1995

Amplifications of proto-oncogenes in ovarian carcinoma.

Thirty-two cases of ovarian carcinoma, two of normal ovaries, four of benign epithelial ovarian tumor, and three of borderline epithelial ovarian tumor were studied using Southern blot hybridization of DNA. In 15 of the 32 cases of ovarian carcinoma, peripheral lymphocytes were also studied. The amplification rate of C-myc, C-N-ras, C-Ki-ras and C-erbB-2 in ovarian carcinoma were 50%, 44%, 31% and 25% respectively. The amplification of C-Ki-ras and C-N-ras took place chiefly in cases of early stage and those of good differentiation. The amplification of C-N-ras was also found in cases of advanced stage. The amplifications of C-myc and C-erbB-2 were chiefly found in cases above stage III and those of poor differentiation. A total of 83% of the patients who died were found to have amplifications of more than 2 proto-oncogenes, with which the amplification of C-erbB-2 was involved.

Adenocarcinoma, Clear Cell↗

PubMed1995

[CF/5-FU-DDP therapy for esophageal carcinoma].

From March 1992 to May 1994, 105 patients with esophageal carcinoma patients were treated with CF/5-Fu-DDP (group A, n = 40) or 5-Fu-DDP (group B, n = 65) protocol. The response rate (CR+PR) was 80% in group A and 60% in group B. (P < 0.01) Induction chemotherapy was followed by surgery or radiation therapy. The incidence of nausea, vomiting, cardiotoxicity and leukopenina was higher in group A than in group B. Buccal mucositis, diarrhea, abdomenal pain and skin pigmentation were noted only in group A. However, the toxic effects were tolerable. The results suggest that the CF/5-Fu-DDP regimen is more effective than 5-Fu-DDP regimen and may be one of the best chemotherapy regimens for the treatment of esophageal carcinoma.

Adult↗