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Biomedical subjects

F Ling

Publications and source records attributed to F Ling.

34 records · Page 2Linked to original sources
PubMed1997

Classification and therapeutic modalities of spinal vascular malformations in 80 patients.

OBJECTIVE: To set up a more detailed classification system for spinal vascular malformations and to discuss the relationship between the classification and therapeutic alternatives. METHODS: Case series from the tertiary care center were studied. Spinal vascular malformations in 80 patients were reviewed and classified into intramedullary arteriovenous malformations (AVMs) (juvenile and glomus AVMs), intradural arteriovenous fistulas (AVFs) (Type I-III), dural AVFs, paravertebral AVMs, and Cobb's syndrome. Therapeutic alternatives to each type of spinal vascular malformations, including surgery, endovascular embolization, and a combination of both, as well as the short-term outcomes, were analyzed. RESULTS: Of the 80 patients, 38 (47.5%) had intramedullary AVMs (23 juvenile and 15 glomus AVMs), 27 (33.8%) had intradural AVFs (6 Type I, 14 Type II, and 7 Type III), 8 (10%) had dural AVFs, and 7 (8.8%) had other malformations. Most of the juvenile AVMs and the Types II and III AVFs were treated by endovascular embolization. Other lesions were treated by surgery or preoperative embolization plus surgery. Among the 76 patients whom we treated, early clinical improvement was achieved in 66 (86.8%). Six (7.9%) remained stable, and four (5.3%) became worse. CONCLUSION: Our classification system offers only limited guidance for the treatment of spinal vascular malformations. Successful treatment in each individual spinal vascular malformation requires correct understanding of the lesion's anatomic location and its angioarchitecture, as well as the limitations of both surgery and endovascular embolization.

Angiography↗
PubMed1997

[Analysis of hexamethylene bisacetamide in biological fluids and tissues by RP-HPLC].

This paper describes the analysis of anticancer drug hexamethylene bisacetamide (HMBA) in biological fluids and tissues by RP-HPLC. The samples of plasmas, urine and tissues from cancer mice and rabbits were first used with methanol for pretreatment to remove protein impurity, then analyzed by RP-HPLC on an ODS column. The mobile phase was methanol/water (70/30, V/V), UV detection is employed at 210 nm. 153 samples were analyzed and good results were obtained. The recoveries of 93.3%-104% with a relative standard deviation of 0.04%. The regression equation is: Y = 0.32X - 1.07, with a linear correlation coefficient of 0.998 and the linear range of HMBA is 0 to 1000 mg/L. A sample analysis can be completed within 13 minutes. This method could be satisfactorily applied not only for the analysis of HMBA but probably also for the analysis of other drugs in biological fluids and tissues.

Acetamides↗
PubMed1997

[A new karyotype of Drosophila albomicans].

In the paper, we present a new karyotype of D. albomicans found in the populations from Southeast China. Short chromosome IV of D. albomicans has been reported in Thailand populations while long type was discovered in Taiwan populations. However, we found that long and short chromosome IV coexisting in the same somatic cells. The individuals which contained the "hybrid" cells were collected from Shanghai, Fuzhou, Xiamen and Shenzhen, China. Moreover, the three karyotypes could be detected in each population mentioned above in other words, the populations showed a pattern of karyotype polymorphism. Furthermore, our observation disclosed that the new karyotype was unstable. Its frequency decreased with increasing breeding generation. Since the geographic locations of these populations just lies between the regions of double long and double short type's populations, this new karyotype seems a intermediate transitional type during the variance process of D. albomicans.

Animals↗
PubMed1996

[The angiographic classification and endovascular therapy of the vein of Galen aneurysmal malformation].

We treated 11 cases of the vein of Galen aneurysmal malformation, one of which was diagnosed by MRI only, and 10 underwent CAG diagnostic procedure. Among the 10 CAG diagnosed cases, 5 were classified as the vein of Galen aneurysmal malformation (VGAM) with the AV shunt directing to the vein of Galen. The other 5 were classified as the vein of Galen aneurysmal dilitation (VGAD) secondary to parenchymal AVM or dural AVF. 8 cases underwent endovascular treatment. For VGAM, the shunts in the wall of the vein were embolized. For VGAD, the primary AVM or AVF were embolized. The pathphysiology, angiographic characteristics, classification and the principle of endovascular therapy of the vein of Galen aneurysmal malformation were discussed.

Adolescent↗
PubMed1995

A nuclear mutation defective in mitochondrial recombination in yeast.

Homologous recombination (crossing over and gene conversion) is generally essential for heritage and DNA repair, and occasionally causes DNA aberrations, in nuclei of eukaryotes. However, little is known about the roles of homologous recombination in the inheritance and stability of mitochondrial DNA which is continuously damaged by reactive oxygen species, by-products of respiration. Here, we report the first example of a nuclear recessive mutation which suggests an essential role for homologous recombination in the stable inheritance of mitochondrial DNA. For the detection of this class of mutants, we devised a novel procedure, 'mitochondrial crossing in haploid', which has enabled us to examine many mutant clones. Using this procedure, we examined mutants of Saccharomyces cerevisiae that showed an elevated UV induction of respiration-deficient mutations. We obtained a mutant that was defective in both the omega-intron homing and Endo.SceI-induced homologous gene conversion. We found that the mutant cells are temperature sensitive in the maintenance of mitochondrial DNA. A tetrad analysis indicated that elevated UV induction of respiration-deficient mutations, recombination deficiency and temperature sensitivity are all caused by a single nuclear mutation (mhr1) on chromosome XII. The pleiotropic characteristics of the mutant suggest an essential role for the MHR1 gene in DNA repair, recombination and the maintenance of DNA in mitochondria.

Base Sequence↗
PubMed1995

Molecular cloning and nucleotide sequence of purine nucleoside phosphorylase and uridine phosphorylase genes from Klebsiella sp.

Klebsiella sp. LF 1202 was isolated as a bacterium that can assimilate adenosine as a sole source of carbon and nitrogen [F. Ling et al., Agric. Biol. Chem., 55, 573-575 (1991)] from a soil sample. Both the purine nucleoside phosphorylase (PNPase) and uridine phosphorylase (UPase) of this bacterium were induced simultaneously when the bacterium was cultured in a medium containing adenosine or uridine as a sole source of carbon and nitrogen. This induction profile is different from that of Escherichia coli. Here we cloned and sequenced the gene corresponding to each enzyme. The open reading frame (ORF) of the PNPase gene consisted of 717 bp that encoded a polypeptide of 239 amino acids with a molecular weight of 26,198. The ORF of the UPase gene consisted of 834 bp that encoded a polypeptide of 278 amino acids with a molecular weight of 28,912.

Amino Acid Sequence↗
PubMed1994

Myelopathy and multiple aneurysms associated with aortic arch interruption: case report.

We report a very unusual association of multiple aneurysms in the cranial cavity and the spinal canal, anterior spinal artery syndrome, syringomyelia, and aortic arch interruption between the origins of the left common carotid artery and the left subclavian artery. A 14-year-old boy with a history of 2 years of flaccid paraplegia and rectal and urinary incontinence after two spontaneous subarachnoid hemorrhages was encountered in August 1993. Through extensive physical and neuroradiological investigation, an association was found. Because almost all infants with aortic arch interruption die within the first month of life, this older patient gave us an opportunity to study the collateral network and the effect of hemodynamic abnormality on the central nervous system. For treatment, we believe that surgery should be directed to the hemodynamic abnormality of the aortic arch interruption. After bypass surgery from the ascending aorta to the abdominal aorta with an artificial vessel graft, the patient had some neurological improvement, as demonstrated by the sensation level lowering from T7 to L1.

Adolescent↗
PubMed1993

[Classification and embolization of spinal cord arterial--venous malformation].

Spinal cord arterial-venous malformation (SCAVM) is a kind of rare disease only accounting for 2%-4% of all spinal diseases. This article reports 41 cases of SCAVM out of 300 times of spinal angiography. The recent classification indicates that out of the 41 cases of SCAVM there are 26 cases of intramedullary AVM. 5 cases of perimedulla AVF. 5 cases of spinal dural AVF. 3 cases of Cobb's syndrome and 2 cases of vertebral angioma. They were treated in three ways: embolization only, embolization plus operation and operation only. As a result, the 5 paralyzed patients (3 cases of Cobb's syndrome and 2 cases of vertebral angioma) recovered totally. The factors influencing satisfactory recovery after SCAVM treatment are as follows: (1) Pure steal flow as the main cause is cured. (2) Intravertebral venous hypertension is alleviated. (3) Intravertebral occupied lesion is solved. The factors for unsatisfactory recovery after SCAVM treatment are as follows: (1) The feeding artery and parenchymal artery are embolized. (2) Drainage vein is damaged or thrombosed. (3) Intramedullary hemomyelia and spinal cord is damaged. (4) There is prolonged ischemia and spinal cord atrophy.

Adolescent↗
PubMed1993

[Super-selective angiography: analysis of angio-architecture and embolization of cerebral arterio-venous malformation].

The angiograms of cerebral arterio-venous malformation (AVM) were analysed through 198 super-selective procedures. The AVM nidus as a whole can be classified as: single supply artery and multi-drainage veins; multi-supply arteries and single drainage vein; multi-supply arteries and multi-drainage veins. Angioarchitecture was divided into five types: terminal supply, penetrating supply, A-V shunt, combined with aneurysm and with anomalous venous structure. Supper-selective angiography was also used for regional functional test and A-V circulation time calculation, as a correct guidance for embolization treatment.

Cerebral Angiography↗
PubMed1990

Purification and characterization of a novel nucleoside phosphorylase from a Klebsiella sp. and its use in the enzymatic production of adenine arabinoside.

An adenosine-assimilating bacterium, Klebsiella sp. strain LF1202, inducibly formed a novel nucleoside phosphorylase which acted on both purine and pyrimidine nucleosides when the cells were cultured in medium containing adenosine as a sole source of carbon and nitrogen. The enzyme was purified (approximately 83-fold, with a 17% activity yield) to the homogeneous state by polyacrylamide gel electrophoresis. The molecular weight of the purified enzyme was calculated to be 125,000 by gel filtration of Sephadex G-200 column chromatography, although the enzyme migrated as a single protein band with a molecular weight of 25,000 on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis; thus, it was thought to consist of five identical subunits. Besides purine nucleosides (adenosine, inosine, and guanosine), the purified enzyme also acted on pyrimidine nucleosides such as uridine, 2'-deoxyuridine, and thymidine. The purified enzyme catalyzed the synthesis of adenine arabinoside, a selective antiviral pharmaceutic agent, from uridine arabinoside and adenine.

Adenine↗
PubMed1989

Rising human chorionic somatomammotropin predicts ectopic pregnancy rupture following methotrexate chemotherapy.

In the medical management of ectopic pregnancy, human chorionic somatomammotropin (hCS) proved to be a more sensitive indicator of continued trophoblastic activity than either beta-human chorionic gonadotropin (beta-hCG) or progesterone (P). In the authors' series of 21 women treated with methotrexate for ectopic pregnancies, only two ruptured. In both cases, hCS levels continued to rise during and after methotrexate treatment. Concomitantly, beta-hCG and P decreased in both of these patients. The authors thus interpret increasing hCS as a reflection of continued syncytiotrophoblast growth, signalling impending rupture. Furthermore, patients with levels of hCS less than 10 ng/ml may require neither medical nor surgical therapy.

Chorionic Gonadotropin↗
PubMed1986

Labial adhesions in a postpartum patient.

The occurrence of labial adhesions in a patient in the immediate postpartum period is described. The adhesions did not respond to topical estrogen therapy, and sharp separation was required. Factors related to possible etiology as well as management of this condition are discussed.

Administration, Topical↗