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Biomedical subjects

B Chang

Publications and source records attributed to B Chang.

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

Large-cell calcifying Sertoli cell tumor of the testis: case report and review of the literature.

Large-cell calcifying Sertoli cell tumor (LCCSCT) is a rare sex cord-stromal tumor found predominantly in the pediatric population. This tumor has distinctive histopathologic features and clinical associations. LCCSCT has also been noted in association with the Carney complex, and in patients with Peutz-Jeghers syndrome. The propensity to metastasize is low, and radical orchiectomy has traditionally been the treatment of choice.

Calcinosis↗
PubMed1998

Removal of the inferior olive abolishes myoclonic seizures associated with a loss of olivary serotonin.

Several lines of clinical evidence suggest that myoclonus is caused by a reduction of serotonin in the brain and hyperactivity of the inferior olive. We determined whether a change in serotonin content within the olivocerebellar system accompanied a predisposition to myoclonus and investigated the necessity of the inferior olive for a myoclonic seizure. The experiments employed the genetically epilepsy-prone rat that exhibits a profound myoclonic seizure in response to an auditory stimulus. We found that these animals demonstrated a significant reduction in the serotonergic innervation of the inferior olive without a significant change in the serotonergic innervation at any other level of the olivocerebellar circuit. The deficit in olivary serotonin was verified physiologically and pharmacologically by a reduced sensitivity of the genetically epilepsy-prone rat to the tremorogenic effect of harmaline, which is known to produce tremor through a mechanism that requires serotonergic innervation of the inferior olive. We quantified the timing of the myoclonic seizure of the genetically epilepsy-prone rat and found that its large amplitude 2-6 Hz clonus was always preceded by 9-10 Hz tremor that was synchronized among limbs. Ablation of the inferior olive by 3-acetylpyridine abolished the myoclonic seizure. The specificity of the deficit in olivary serotonin, the timing of the seizure, and the demonstration of the necessity of the inferior olive for myoclonus suggest that pathological inferior olivary activity contributes to the genesis of a myoclonic seizure.

Acoustic Stimulation↗
PubMed1998

Identification and cloning of a truncated isoform of the cardiac sodium-calcium exchanger in the BALB/c mouse heart.

A truncated isoform of the cardiac sodium-calcium exchanger (NCX1) was identified and cloned from BALB/c mouse heart. This cDNA clone has an AATAAA polyadenylation signal in the 3' untranslated region that caused the 3344-bp clone to stop at a premature termination site and encode for a 940-amino acid (AA) protein, in contrast to the wild-type C57BL/6 mouse, which has a 970-AA protein. Comparing the predicted AA sequence of NCX1 between the two mouse strains by hydropathic plot, we found that the BALB/c NCX1 protein has only 11 extracellular domains, missing one domain at the COOH terminal, while C57BL/6 mice have 12 extracellular domains, similar to other species. Using the mouse mapping gene panel BCB, the NCX1 gene was mapped to the distal end of mouse chromosome 17 (51.3 cM), confirming the data published from the rat probe.

Amino Acid Sequence↗
PubMed1998

Dacryocystorhinostomy in south west England.

PURPOSE: To assess the pre-operative management, surgical technique employed, success rate and patient satisfaction following surgery in patients undergoing dacryocystorhinostomy (DCR) in South West England. METHOD: Two hundred and forty-two patients who underwent DCR were retrospectively studied. A telephone questionnaire was used to assess patient satisfaction in 100 patients. RESULTS: One hundred and thirteen (46%) patients had nasolacrimal duct obstruction, half of whom had a history of dacryocystitis, 70 (29%) had canalicular obstruction and 8 (3%) had mixed blockage. The site of blockage was not known or recorded in 51 patients (22%). Seventy-five (31%) patients underwent DCR, 151 (62%) DCR with insertion of silicon tubes, 9 (4%) DCR and Lester Jones tube, and 7 (3%) canaliculodacryocystorhinostomy (CDCR). Overall an 83.5% success rate was reported by the surgeons. The success rate for patients with a history of dacryocystitis was 98%, for nasolacrimal duct obstruction 96% and for canalicular obstruction 82%. When the site of blockage was not known or recorded the success rate was 60%. Where the name of the surgeon was not recorded there was a 15% successful outcome. Eighty per cent of patients reported some improvement in their symptoms following surgery. CONCLUSIONS: DCR is an effective surgical procedure with a high rate of patient satisfaction. Pre-operative identification of the site of the blockage is likely to improve surgical outcome.

Adolescent↗
PubMed1998

The effect of intracameral, per-operative antibiotics on microbial contamination of anterior chamber aspirates during phacoemulsification.

PURPOSE: To assess the effect of per-operative antibiotics on contamination of anterior chamber (AC) aspirates during phacoemulsification. METHODS: Two hundred and twenty patients undergoing phacoemulsification of cataract were randomly allocated to receive an irrigation infusion fluid containing either balanced salt solution (BSS) alone or BSS with vancomycin (20 mg/l) and gentamicin (8 mg/l) during surgery. Conjunctival swabs were obtained from all patients immediately before pre-operative preparation. At the end of surgery 20 ml of the AC aspirate was sent for direct and enrichment cultures. Qualitative and quantitative microbiological studies were undertaken. The chi-squared test was used to compare differences between the two groups. RESULTS: There was no significant difference between the positive culture rates of the conjunctival swabs (28 vs 27; p > 0.8). In the group that received BSS alone there were 22 (20%) positive AC aspirate cultures, 18 of which were from enrichment cultures. There were 3 positive (2.7%) cultures from the group that received antibiotics added to the BSS (p < 0.0001). CONCLUSION: The addition of gentamicin and vancomycin to the irrigation fluid during phacoemulsification results in a highly significant reduction in the microbial contamination of AC aspirates.

Anterior Chamber↗
PubMed1998

Antimicrobial activity of magnolol and honokiol against periodontopathic microorganisms.

Magnolol (1) and honokiol (2), main compounds from the stem bark of Magnolia obovata Thunb., were evaluated for an antimicrobial activity against periodontopathic microorganisms, Porphyromonas gingivalis, Prevotella gingivalis, Actinobacillus actinomycetemcomitans, Capnocytophaga gingivalis, and Veillonella disper, and a cytotoxicity against human gingival fibroblasts and epithelial cells. Our results indicate that magnolol and honokiol, although less potent than chlorhexidine, show a significant antimicrobial activity against these microorganisms, and a relatively low cytotoxic effect on human gingival cells. Thus, it is suggested that magnolol and honokiol may have a potential therapeutic use as a safe oral antiseptic for the prevention and the treatment of periodontal disease.

Aggregatibacter actinomycetemcomitans↗
PubMed1998

Carotid endarterectomy surgery and ICU admissions: a regional anesthesia perspective.

Stroke is a major cause of mortality and morbidity in the United States. This study was performed to determine whether the authors' practice of monitoring the majority of patients in the postanesthesia care unit for 2 hours, selectively admitting the recovering carotid endarterectomy patients to the intensive care unit when feasible, and using regional anesthesia for the majority of cases, resulted in adverse outcomes or compromised the safety of the operation at a tertiary care academic medical center. The records of 337 patients (a total of 420 procedures) who underwent carotid endatertectomy surgery without concurrent heart surgery during a consecutive 18-month period ending in June, 1995 were reviewed. Regional anesthesia was the technique used in 97% of the procedures. Shunt placement was deemed necessary in 7% of the procedures. Postoperative strokes occurred in approximately 1% of patients. No shunted patients had a postoperative stroke. The rate of admission to intensive care units was 4%. Blood pressure control accounted for 73% of the patients admitted to intensive care units. Most patients required 2 hours of monitoring in the postanesthesia care unit before triage to the appropriate level of postoperative care. These results suggest that a monitoring period of 2 hours in the postanesthesia care unit allows for safe assessment of the postoperative carotid endarterectomy patient, and that routine intensive care unit admission after carotid endarterectomy surgery is not necessary.

Adult↗
PubMed1998

Filamentous bacteriophages of Vibrio parahaemolyticus as a possible clue to genetic transmission.

We have previously reported the isolation and characterization of two filamentous bacteriophages of Vibrio parahaemolyticus, designated Vf12 and Vf33. In this study, to understand the potential of these phages as tools for genetic transmission, we investigated the gene structures of replicative-form (RF) DNAs of their genomes and the distribution of these DNAs on chromosomal and extrachromosomal DNAs. The 7,965-bp nucleotide sequences of Vf12 and Vf33 were determined. An analysis of the overall gene structures revealed that Vf12 and Vf33 had conserved regions and distinctive regions. The gene organization of their conserved regions was similar to that of CTX phage of Vibrio cholerae and coliphage Ff of Escherichia coli, while their distinctive regions were characteristic of Vf12 and Vf33 phage genomes. Southern blot hybridization testing revealed that the filamentous phage genomes integrated into chromosomal DNA of V. parahaemolyticus at the distinctive region of the phage genome and were also distributed on some plasmids of V. parahaemolyticus and total cellular DNAs of one Vibrio damsela and one nonagglutinable Vibrio strain tested. These results strongly suggest the possibilities of genetic interaction among the bacteriophage Vf12 and Vf33 genomes and chromosomal and plasmid-borne DNAs of V. parahaemolyticus strains and of genetic transmission among strains through these filamentous phages.

Bacteriophages↗
PubMed1998

Improved FNA cytology results with a near patient diagnosis service for non-breast lesions.

AIM: To review fine needle aspiration (FNA) cytology from sites other than the breast a year before and a year after the introduction of a near patient FNA diagnosis (NPFD) service in which the FNA were performed by a pathologist and reported within a few minutes. METHODS: The setting was a large hospital in rural New Zealand. The year before the introduction of the NPFD service was examined retrospectively, and the year after prospectively. The pattern of use and the quality of the results before and after starting the NPFD service were compared. RESULTS: Time taken to report the specimens decreased from a few days to a few minutes. There were statistically significant changes in the following: an increase from 237 to 304 in the number of non-breast FNA performed, and in particular an increase from 65 to 113 in the number for general surgery; an increase in the use of immunolabelled flow cytometry from 0 to 19 and cell blocks from 3 to 41; an increase in specificity from 53% to 80%; a decrease in the overall inadequacy rate from 29% to 9%; and a decrease in the inadequacy rate for cancers from 9% to 2%. The cost of the non-breast FNA service increased by about 9200 Pounds a year. CONCLUSIONS: Starting an NPFD service for sites other than the breast greatly reduced the reporting time and produced statistically significant increases in the use of FNA cytology and in the quality of the results.

Biopsy, Needle↗
PubMed1998

Mutations of p53 gene can be detected in the plasma of patients with large bowel carcinoma.

AIMS: To attempt to detect p53 gene mutations in the plasma of patients with large bowel carcinoma. METHODS: Plasma was collected from 20 control patients with no history of cancer and from 17 patients with large bowel carcinoma. Corresponding tumour and benign lymph node (control) samples for each of the carcinoma patients were obtained from paraffin blocks. A Dukes' stage was determined for each tumour. DNA was extracted from the plasma samples and the paraffin embedded tissue using previously described methods. A nested primer polymerase chain reaction protocol was used for the amplification of exons 5 to 8 of the p53 gene. "Cold" single strand conformational polymorphism (SSCP) was performed on mini gels and silver stained. Abnormal bands were excised, the DNA eluted, and reamplified for automated dye termination sequencing. Any sample showing an apparent mutation was rechecked from the original extracted DNA sample at least three times. RESULTS: p53 gene mutations were not found in the control specimens. They were found in both the primary tumour and the plasma in three cases, in the primary tumour alone in one case, and in the plasma alone in two cases. One of the latter two cases also had metastatic transitional cell carcinoma of the bladder and the other had widespread metastatic deposits. One of the cases with mutant DNA in both the plasma and the primary was a Dukes' stage B tumour. The others were Dukes' C and Dukes' D. CONCLUSIONS: p53 gene mutations can be detected in the plasma of some patients with large bowel carcinoma and these are concordant with those in the primary carcinomas.

Adult↗
PubMed1998

[The effect of herbal medicine including astragalus membranaceus (fisch) bge, codonpsis pilosula and glycyrrhiza uralensis fisch on airway responsiveness].

OBJECTIVE: To study the effect of astragalus membranceus(fisch) bge, codonpsis pilosula and glycyrrhiza uralensis fisch on airway responsiveness. METHOD: FVC, FEV1 and PEF of twenty-eight asthmatic patients were measured before and six weeks after treated with Astragalus membranceus(fisch) bge, codonpsis pilosual and glycyrrhiza uralensis fisch; methacholine challenge test with 0.033 mumol and 1.98 mumol. RESULT: After 28 asthmatic patients received the treatment of those herbs, the results showed that FVC value increased obviously (t = 2.217, P < 0.05) and the value of FEV1 and PEF was all higher compared with before treatment of the herbs (P < 0.01). CONCLUSION: The herbal medicine including astragalus memberanaceus (fisch) bge, codonpsis pilosual and glycyrrhiza uralensis fisch can decrease the airway responsiveness of the patients with asthma.

Adolescent↗
PubMed1998

[Application of immunochromatographic test for diagnosis and surveillance of bancroftian filariasis].

AIM: To evaluate the usefulness of immunochromatographic test (ICT) for rapid diagnosis and surveillance of Wuchereria bancrofti infection. METHODS: The monoclonal antibody based-ICT assay was used to detect filarial antigens in the sera from bancroftian filariasis patients. RESULTS: 111 out of 116 bancroftian microfilaria cases showed positive ICT reaction, giving a positive rate of 95.7%. Serum samples from 12 malayian microfilaremia cases, 33 ascariasis cases, 20 schistosomiasis japonica cases and 6 trichinellosis cases were all found negative in ICT, demonstrating a specificity of 100%. In 73 chronic filariasis cases with elephantiasis, hydrocoele, and chyluria cases, 18 showed ICT positive, among whom 16 revealed microfilaremia, suggesting that the ICT positive cases were with active infections. Of the 30 microfilaremia cases before single dose ivermectin treatment, 29 were ICT positive (96.7%). A negative conversion of microfilaremia was observed in all cases 8-14 days post-treatment. Upon following up to 6 and 12 months, microfilaremia reappeared in 5 and 7 cases, respectively. 5 out of 13 ICT positive cases were found microfilaremic at 6 month post-treatment, while among the rest of 8, 5 were found microfilaremic at 12 month post-treatment. Parallel use of ICT with routine blood film examination in Houda village, Zhecheng County, Henan Province for a post-control surveillance survey in 132 local individuals revealed 9 microfilaremia cases were also ICT positive. Of the 123 persons with negative blood examination, only 1 was ICT positive. CONCLUSION: ICT is a rapid and simple method with high sensitivity and specificity, and might be used for the diagnosis, efficacy evaluation as well as a tool for post-control surveillance of bancroftian filarasis.

Animals↗
PubMed1998

Essential iris atrophy, pigment dispersion, and glaucoma in DBA/2J mice.

PURPOSE: To characterize ocular abnormalities associated with iris atrophy in DBA/2J mice and to determine whether mice of this strain develop elevated intraocular pressure (IOP) and glaucoma. METHODS: Different approaches, including slit-lamp biomicroscopy, ophthalmoscopic examination, ultrasound backscatter microscopy, and histology were used to examine the eyes of DBA/2J mice ranging from 2 to 30 months old. IOP was measured in DBA/2J mice of different ages. RESULTS: DBA/2J mice were found to develop pigment dispersion, iris transillumination, iris atrophy, anterior synechias, and elevated IOP. IOP was elevated in most mice by the age of 9 months. These changes were followed by the death of retinal ganglion cells, optic nerve atrophy, and optic nerve cupping. The prevalence and severity of these lesions increased with age. Optic nerve atrophy and optic nerve cupping was present in the majority of mice by the age of 22 months. CONCLUSIONS: DBA/2J mice develop a progressive form of secondary angle-closure glaucoma that appears to be initiated by iris atrophy and the associated formation of synechias. This mouse strain represents a useful model to evaluate mechanisms of pressure-related ganglion cell death and optic nerve atrophy, and to evaluate strategies for neuroprotection.

Aging↗
PubMed1997

Pharmacy-managed program for home treatment of deep vein thrombosis with enoxaparin.

A program for home treatment of uncomplicated acute proximal deep vein thrombosis (DVT) with enoxaparin is described. In fall 1995 an HMO in Southern California began developing a pharmacy-managed program in which selected patients with acute proximal DVT receive home treatment with enoxaparin. Advantages of the program included expected cost avoidance. The safety and efficacy of such therapy were verified, and quality control measures were established. Patients are referred to the program by the physicians making the diagnosis of proximal DVT. Upon referral, patients are placed in a holding area. A pharmacist orders laboratory tests and then prescribes warfarin and enoxaparin doses. Patients are given their first doses, taught to safely self-administer enoxaparin, and sent home. Follow-up care, monitoring, and blood sampling are provided through a home health agency. A pharmacist monitors the International Normalized Ratio (INR) and telephones the patient daily to specify the day's warfarin dose. Patients receive concurrent enoxaparin and warfarin therapy for at least five days until the INR is > 2; enoxaparin is then discontinued and patients are transferred to an outpatient anticoagulation service for continued monitoring. From April 1, 1996, to March 27, 1997, 55 patients were treated under the program; all eligible patients were enrolled. A total of 294 hospital days were avoided. There were no complications or hospital admissions due to bleeding. A comprehensive program for home treatment of uncomplicated acute proximal DVT with enoxaparin was implemented at an HMO.

Acute Disease↗
PubMed1997

A new dominant retinal degeneration (Rd4) associated with a chromosomal inversion in the mouse.

An autosomal dominant retinal degeneration, called Rd4, was found in a stock carrying the inversion In(4)56Rk, which was induced in a DBA/2J male. The inversion encompasses nearly all of Chromosome 4. It is homozygous lethal and in heterozygotes is always associated with retinal degeneration. In affected mice, the retinal outer nuclear and plexiform layers begin to reduce at 10 days of age, showing total loss at 6 weeks. The recordable electroretinograms (ERG) showed poorly at 3 to 6 weeks and were barely detected after 6 weeks of age. Retinal vessel attenuation, pigment spots, and optic atrophy appeared in the fundus at 4 weeks of age. Rd4 has not recombined with the inversion in an outcross, suggesting that the Rd4 locus is located very close to or is disrupted by one of the breakpoints of the inversion, either near the centromere or near the telomere. A human homolog would be expected to be located on human chromosomes 1p or 8q.

Animals↗
PubMed1997

Association between enhanced Th2/Th1 cytokine profile and donor T-cell chimerism following total lymphoid irradiation.

Total lymphoid irradiated (TLI) mice develop antigen specific tolerance if the initial antigen exposure occurs shortly after the completion of TLI. We injected TLI-treated mice with semiallogeneic donor cells at 2, 7, or 28 days after completing TLI and determined the levels of donor CD4 and CD8 cells 5 to 7 weeks after TLI treatment. The level of chimerism correlated with the timing of the initial alloantigen exposure. Donor CD4 and CD8 cells were noted only in day 2 or 7 injected mice. Because donor cell chimerism suggested increased in vivo survival of donor cells, we used the level of donor cell chimerism as a surrogate marker for tolerance to examine the relationship between the development of tolerance and enhanced Th2/Th1 cytokine responses to donor antigen. Increased levels of donor CD4 and CD8 cells in the TLI-treated mice was associated with increased Th2/Th1 cytokine production and decreased CTL activity to donor antigen in vitro. Higher Th2/Th1 cytokine levels also correlated with lower CTL activity. The results indicate that the increased production of Th2/Th1 may function to enhance survival of donor cells in TLI-treated mice and suggest that tolerance induction after TLI treatment involves immunoredirection.

Animals↗