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Biomedical subjects

X Tang

Publications and source records attributed to X Tang.

At least 253 records · Page 14Linked to original sources
PubMed1995

[Osteoclastic resorption of Haversian system of femoral neck cortex in aged women].

Osteoclastic resorption was studied with scanning electron microscope on cross sections of cortical bone of femoral neck collected from 7 aged women with an average age of 72.4 years, who underwent endoprosthetic replacement for intracapsular hip fracture. The cortical bone sections revealed enlargement of the Haversian canals. On the inner linings of the enlarged canals there were many oval-shaped resorption lacunae, reflecting osteoclastic resorption of the Haversian systems. The osteoclastic resorption with subsequent enlargement of the Haversian canals into round or oval cavities took place first over the inner portions of the cortical sections, thereby rendering these areas porotic (cancellization). These processes of the Haversian system and canals then gradually emerged over the central and eventually over the outer areas of the cortical bone, and the entire cortical bone became porotic. In the meanwhile, the inner porotic portion of the cortex turned into trabeculae (trabecularization) and became gradually resorbed, resulting in thinning of the medial cortex. Cortical cancellization, trabecularization and thinning so compromised the material strength of the femoral neck that fracture would ensue even with trivial injury.

Aged↗
PubMed1995

Carpal tunnel syndrome: etiological, clinical and electrophysiological aspects of 262 cases.

Two hundred and sixty-two patients with carpal tunnel syndrome (CTS) were analyzed retrospectively. Results showed that middle- and older-age women were more apt to have CTS than men, and that the dominant hand was more frequently affected. Hormonal changes, repetitive and forceful movements, awkward positions of hand and wrist, and other factors may be associated with CTS. Typical clinical manifestations include pain and paresthesia in the median nerve territory, worsening at night or in the early morning, and being relieved by shaking the hand. Although the patients may localize the discomfort beyond the territory, sensory changes are variable and not entirely reliable. Conduction abnormalities often appeared selectively in the median nerve distal to the wrist in CTS. If the patient who is clinically suggestive of CTS shows normal conduction with conventional methods, palmar stimulation and inching technique is recommended. The diagnosis of CTS requires confirmation of illness history, symptoms and signs with objective electrodiagnostic tests.

Adult↗
PubMed1995

[A study on the mechanism of the cardiac adenylyl cyclase activity alteration in septic rats].

The present work showed that cardiac sarcolemmal (SL) adenylyl cyclase (AC) and purified AC maximal activity of septic rat (cecal ligaation and puncture, CLP) were significantly increased during the early sepsis (ES, CLP 9 h) but decreased in the late sepsis (LS, CLP 18 h). Similar alterations were observed in cardiac sarcolemmal protein kinase C (PKC) activity. Sensitization and desensitization of rat SL adenylyl cyclase during ES and LS were respectively correlated with activition and inhibition of PKC. The biphasic changes of AC and PKC were independent of beta- and alpha 1-adrenergic receptor systems. The rat cardiac sarcolemmal PKC activation and AC sensitization during ES is related to M-cholinergic receptor system. The system, however, is not involved during the LS PKC inhibition and AC desensitization.

Adenylyl Cyclases↗
PubMed1995

[Histological study of uterine cervix during termination of early pregnancy by mifepristone and prostaglandins].

OBJECTIVE: To study the histological changes of uterine cervix during termination of early pregnancy by mifepristone and prostaglandins (PG). METHODS: A total of 24 women who requested medical abortion was recruited. For each woman, 3 cervical biopsies were taken: before mifepristone treatment; 48 hours after mifepristone 150 mg single dose treatment (i.e. immediately before PG administration); and 1 hour after gestational sac expulsion. Specimens were studied by optical and electron microscopy. RESULTS: Significant collagenolysis as demonstrated by marked reduction and irregularity of collagen fibers, abundant accumulation of an amorphorous material of ground substance, and infiltration of neutrophilic polymorphonuclear leukocytes were shown in stroma as well as in the deep portion of cervix after mifepristone as compared to the samples of early pregnant cervix before treatment. These changes presented to a further extent after the expulsion of gestational sac. CONCLUSION: The changes observed were similar to previous reports during cervical dilatation in term delivery. The present study confirmed the histological cervical ripening effect by mifepristone and suggested it may be used as cervical ripening agent before induction of labor as well.

Abortifacient Agents, Nonsteroidal↗
PubMed1995

Guillain-Barre syndrome in six cities and provinces of northern China: is it a new entity?

Forty cases of Guillain-Barre Syndrome were reported, (GBS) which came from the regions where "Chinese Paralytic Syndrome" and "Acute Motor Axonal Neuropathy (AMAN)" were presented before. A study on their clinical, electrophysiological and pathological features was conducted, records on 3,733 GBS cases reported in northern China from 1978 to 1992 were reviewed and compared with cases of "acute moter axonal nouropathy". The results showed that the clinical, electrophysiological and pathological features of GBS in north China are similar to those of typical GBS cases in western countries, though there seemed to be some special epidemiological features in age, seasonal and regional distribution. It was concluded that the GBS in northern China is demyelinating GBS dominantly, not a new entity.

China↗
PubMed1995

[Risk factors for Guillain-Barre syndrome in northern China: a case-control study].

We conducted a case-control study in northern China to estimate possible risk factors for Guillain-Barre Syndrome (GBS). Forty patients were consecutively seen at the PUMC hospital and the Second Hospital of Hebei Medical College between July and September 1991. The diagnosis was established following the NINCDS criteria for GBS. Among 36 patients with measurements of motor evoked potentials, 34 had evidences of demyelination. Eighty controls chosen from spouses or siblings, and neighbors or work/school mates, were matched by sex and age (+/- 3 years). Using the Mantel-Haenszel estimate of the odds ratio, cold rain, overloaded activities, a history of diarrhea, common cold, and exposure to organophosphorus one month before onset, significantly increased, at least six-fold, the risk for development of GBS. Cases and controls did not differ in the number of previous vaccinations. We suggest that a single antigent is less likely of etiological importance in GBS.

Adolescent↗
PubMed1995

[Malignant melanoma of nasal cavity: report of 24 cases].

The malignant melanoma of nasal cavity is one of the refractory diseases. The malignant degree and the recurrent rate of this disease are high. And it is very easy to make misdiagnosis. This article reviewed the clinical and pathological data of malignant melanoma of nasal cavity for 20 years from 1971 to 1991. All the patients were followed up. We found that there were altogether 24 cases of this disease which covered 0.02% of all the inpatients during that period of time. The pathological characteristics of this tumor showed that there was a typical fore-melanin body in different tumor cells. If we pay attention to the minor and grained melanin, misdiagnosis can be avoided. Surgery is the first choice for this disease. And the post-operative radiotherapy, laser therapy gives a better result.

Adult↗
PubMed1995

I-cell disease: report of an autopsy case.

The history and findings at autopsy of a 9-year-old female with I-cell disease are reported. She manifested gargoyle face, progressive psychomotor retardation, and increased serum levels of lysosomal enzymes with decreased activities in peripheral blood lymphocytes. She received a bone marrow transplantation from her HLA-mismatched father when she was 8 years old. Rejection followed, and 9 months later, she died of cardiac failure secondary to aortic regurgitation. The characteristic inclusion bodies, ultrastructurally corresponding to double-membranous lamellar vacuoles and empty single membrane-bound vacuoles, were identified in dermal fibro blasts, macrophages, glomerular epithelial cells, cardiomyocytes and smooth muscle cells. Pale bodies, faintly eosinophilic cytoplasmic globular inclusions immunoreactive for plasma proteins, were observed in hepatocytes and renal collecting tubular epithelial cells. Enzyme histochemical analyses were performed for N-acetyl-beta-glucosaminidase, beta-glucuronidase, nonspecific esterase and acid phosphatase. Decreased activities of the acid hydrolases and their diffusion in the cytoplasm were seen in Kupffer's cells. Ultrastructural localization of acid phosphatase activity suggested the labilization of the lysosomal membrane. The abnormality in the intracellular transport of the acid hydrolases into the lysosomes in I-cell disease is briefly reviewed and discussed.

Acid Phosphatase↗
PubMed1994

Protein kinase domain of twitchin has protein kinase activity and an autoinhibitory region.

Twitchin is a 753-kDa polypeptide located in the muscle A-bands of the nematode, Caenorhabditis elegans. It consists of multiple copies of both fibronectin III and immunoglobulin C2 domains and, near the C terminus, a protein kinase domain with greatest homology to the catalytic domains of myosin light chain kinases. We have expressed and purified from Escherichia coli twitchin's protein kinase catalytic core and flanking sequences that do not include fibronectin III and immunoglobulin C2 domains. The protein was shown to phosphorylate a model substrate and to undergo autophosphorylation. The autophosphorylation occurs at a slow rate, attaining a maximum at 3 h with a stoichiometry of about 1.0 mol of phosphate/mol of protein, probably through an intramolecular mechanism. Sequence analysis of proteolytically derived phosphopeptides revealed that autophosphorylation occurred N-terminal to the catalytic core, predominantly at Thr-5910, with possible minor sites at Ser5912 and/or Ser-5913. This portion of twitchin (residues 5890-6268) was also phosphorylated in vitro by protein kinase C in the absence of calcium and phosphotidylserine, but not by cAMP-dependent protein kinase. By comparing the activities of three twitchin segments, the enzyme appears to be inhibited by the 60-amino acid residues lying just C-terminal to the kinase catalytic core. Thus, like a number of other protein kinases including myosin light chain kinases, the twitchin kinase appears to be autoregulated.

Amino Acid Sequence↗
PubMed1994

DNA fingerprinting involving fluorescence-labeled termini of any enzymatically generated fragments of DNA.

We have developed a new fluorescence-based method for DNA fingerprinting that does not require a fluorescent linker or a synthetic oligonucleotide primer, both of which are normally used for labeling of DNA. Cosmid DNAs are digested with appropriate restriction enzymes and the 3' termini of DNA fragments are labeled with the corresponding, fluorescent dye-conjugated dideoxynucleotide triphosphate terminator (dye-ddNTP) by the Klenow fragment of DNA polymerase I from Escherichia coli, which has 3'-->5' exonuclease and replacement activities as well as its main 5'-->3' polymerase activity. Samples are separated on a DNA-sequencing gel and data are analyzed by application of both the Version 0.3.8a mapper program (Applied Biosystem Inc., Foster City, CA) and our Overlap I program that facilitate rapid analysis of the frequency of overlapping of cosmid DNAs. Using this method we have determined the overlap frequency of DNA fragments of each cosmid clone from the mouse MHC class I gene cluster.

Animals↗
PubMed1994

Genomic structure and chromosomal localization of processed pseudogenes for human RBP-Jk.

The functional gene for human recombination signal sequence-binding protein (RBP-Jk) and corresponding processed psudogenes have been isolated from various species, such as Drosophila, Xenopus, mouse, and human. Here we report the isolation of another two genomic pseudogenes of human RBP-Jk, named K2 and K7, from a cosmid library of Hela cells. The nucleotide sequences of both genes exhibited more than 95% homology to the functional human gene for RBP-Jk. Moreover, they did not contain any intron sequences and were interrupted by several stop codons in all frames. In situ hybridization demonstrated that the pseudogenes, K2 and K7, were localized at chromosomes 9p13 and 9q13, respectively. Their physical maps differed from those of the true functional gene and of the pseudogenes reported previously by Amakawa et al. (1993).

Base Sequence↗