Isolation of novel microorganism from gastric biopsy specimen.
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Bacteria↗
Biomedical subjects
N Chang
Publications and source records attributed to N Chang.
Protein separation and purification in neat dimethyl sulfoxide.
Pure DMSO (instead of water) is used as the reaction medium for protein separations. It is shown that common extracellular proteins (i) have high solubility in DMSO (1-50 mg/ml), (ii) do not irreversibly inactivate in this solvent, and (iii) can adsorb onto carboxymethyl cellulose in DMSO and be subsequently fully desorbed in this solvent by inorganic salts. Ion-exchange chromatography on this resin in DMSO has been used to purify bovine pancreatic trypsin and to separate it from hen egg-white lysozyme in their mixture. Another approach to protein separation in DMSO, fractional precipitation with ethyl acetate (which does not dissolve proteins), has been verified with a mixture of bovine pancreatic chymotrypsinogen and chicken egg ovalbumin.
Animals↗
Pulsed-field gel electrophoresis of Campylobacter jejuni and Campylobacter coli genomic DNA and its epidemiologic application.
Genomic DNA from 12 different Campylobacter jejuni and 10 Campylobacter coli isolates was digested with SmaI and analyzed by pulsed-field gel electrophoresis (PFGE) and 16S rRNA hybridization studies. Although the two Campylobacter species displayed species-specific restriction and hybridization patterns, significant intraspecies differences were observed. Combined PFGE and hybridization pattern analysis failed to provide any more epidemiologic information than was obtained from PFGE restriction profiles alone. Therefore, results from these studies indicate that PFGE analysis of SmaI-restricted genomic DNA provides a reliable means of differentiating C. jejuni from C. coli and may represent a more practical approach to epidemiologic studies than combining conventional DNA restriction digestion pattern with RNA hybridization procedures.
Animals↗
In vitro susceptibilities of Campylobacter jejuni and Campylobacter coli to azithromycin and erythromycin.
MICs of azithromycin and erythromycin for 20 Campylobacter coli and 20 Campylobacter jejuni strains were determined. The results demonstrated that, for Campylobacter species, all high-level erythromycin-resistant strains were also resistant to azithromycin and that azithromycin did not exhibit increased potency in comparison with that of erythromycin.
Azithromycin↗
Lead exposure among mothers and their newborns in Toronto.
Recent studies have suggested that a fetal blood lead level of 0.48 mumol/L (much lower than 1.21 mumol/L, which is the level previously believed to be toxic to the developing brain) may impair brain development permanently. We measured the maternal and umbilical cord blood levels of lead and free erythrocyte protoporphyrin (FEP) among 95 consecutive mother-infant pairs to determine whether neonates in Toronto are in the high-risk group. There was a significant correlation between the maternal and the cord blood lead levels (r = 0.59, p less than 0.0001). Most (99%) of the infants had cord blood lead levels below 0.34 mumol/L; in 11 cases the levels were below the detection limit of 0.01 mumol/L. The cord blood FEP levels were higher than the maternal levels. The US Centers for Disease Control, Atlanta, currently finds acceptable a blood FEP level of 0.62 mumol/L among children up to 10 years of age; however, this is not applicable to newborns since their higher FEP levels apparently reflect immature heme synthesis and increased erythrocyte volume rather than lead poisoning. Our data suggest that living in Toronto does not impose increased teratogenic risk from intrauterine exposure to lead; however, residents in high-risk areas should be followed up.
Adult↗
Use of pulsed-field agarose gel electrophoresis to size genomes of Campylobacter species and to construct a SalI map of Campylobacter jejuni UA580.
To determine the physical length of the chromosome of Campylobacter jejuni, the genome was subjected to digestion by a series of restriction endonucleases to produce a small number of large restriction fragments. These fragments were then separated by pulsed-field gel electrophoresis with the contour-clamped homogeneous electric field system. The DNA of C. jejuni, with its low G+C content, was found to have no restriction sites for enzymes NotI and SfiI, which cut a high-G+C regions. Most of the restriction enzymes that were used resulted in DNA fragments that were either too numerous or too small for genome size determination, with the exception of the enzymes SalI (5' ... G decreases TCGAG ... 3'), SmaI (5' .... CCC decreases GGG .... 3'), and KpnI (5' ... GGTAC decreases C .... 3'). With SalI, six restriction fragments with average values of 48.5, 80, 110, 220, 280, and 980 kilobases (kb) were obtained when calibrated with both a lambda DNA ladder and yeast Saccharomyces cerevisiae chromosome markers. The sum of these fragments yielded an average genome size of 1.718 megabases (Mb). With SmaI, nine restriction fragments with average values ranging from 39 to 371 kb, which yielded an average genome size of 1.726 Mb were obtained. With KpnI, 11 restriction fragments with sizes ranging from 35 to 387.5 kb, which yielded an average genome size of 1.717 Mb were obtained. A SalI restriction map was derived by partial digestion of the C. jejuni DNA. The genome sizes of C. laridis, C. coli, and C. fetus were also determined with the contour-clamped homogeneous electric field system by SalI, SmaI, and KpnI digestion. Average genome sizes were found to be 1.714 Mb for C. coli, 1.267 Mb for C. fetus subsp. fetus, and 1.451 Mb for C. laridis.
Base Sequence↗
A study of the relationship between blood flow and bacterial inoculation in musculocutaneous and fasciocutaneous flaps.
Regional nutrient blood flow to musculocutaneous and fasciocutaneous flaps was studied in dogs using 15-microns radiolabeled microspheres, and correlations to bacterial inoculation into closed wound spaces were sought. During the 6-day study period, no differences were found between blood flow to noinoculated versus inoculated flaps. Comparisons of blood flow to the deep surfaces of the flaps showed that blood flow to muscle in musculocutaneous flaps increased rapidly during the first 24 hours and then plateaued, while that to subcutaneous tissue plus fascia in fasciocutaneous flaps demonstrated a gradual and steady increase. The most rapid decline in bacterial counts at the undersurface of both flaps occurred within 24 hours, dropping significantly lower within musculocutaneous flaps. In addition to such surface properties of muscle as tissue ingrowth, rapid early augmentation of muscle blood flow may be largely responsible for superior bacterial suppression observed beneath musculocutaneous flaps.
Animals↗
Latissimus dorsi muscle-musculocutaneous flap in chest-wall reconstruction.
The latissimus dorsi is a versatile muscle that can be employed in a variety of situations requiring chest-wall reconstruction. Its anatomy is predictable and has within it flexibility for transposition to a number of locations based on its standard or reverse arcs of rotation. It can be transposed with a skin island, and its length and bulk can be used effectively to provide durable coverage for anterior or posterior defects. These factors make the latissimus dorsi an excellent choice for the reconstruction of complex chest-wall defects.
Humans↗
Peritoneal cytology of ovarian cancer patients receiving intraperitoneal therapy: quantitation of malignant cells and response.
An analysis was performed of malignant and host cells found in peritoneal fluids obtained during intraperitoneal chemotherapy and immunotherapy in patients with ovarian cancer. The concentration of malignant cells and the surgically documented response to the intraperitoneal treatment were correlated. Twenty-three patients were treated with intraperitoneal cisplatin or alpha-2 interferon (rIFN-alpha 2) after persistent carcinoma was documented at second-look laparotomy. Six patients (26%) had a complete response to therapy, and all of these patients had a malignant cell concentration of less than 10(2)cells/cm2/dL. No responses were seen in patients whose initial malignant cell concentration was greater than 10(3)cells/cm2/dL. Among patients treated with intraperitoneal alpha-interferon, five of 11 whose initial concentration of malignant cells was less than 10(2) cells/cm2/dL responded to therapy, whereas none of the patients whose malignant cell concentration was 10(2) cells/cm2/dL or greater responded. In patients treated with intraperitoneal cisplatin, the initial concentration of malignant cells associated with any surgically documented response was less than 10(3)cells/cm2/dL. A host mesothelial reaction was prominent after intraperitoneal alpha-interferon, but not observed in women treated with intraperitoneal cis-platin. The fluctuating pattern of peritoneal white blood cells documented during therapy did not correlate with response. THe evaluation of peritoneal cytology specimens during intraperitoneal chemotherapy should include a quantitative assessment of malignant cells and reactive mesothelial cells in order to reflect more accurately the histologically documented findings. Initial quantitative cytology appears to correlate with the likelihood of a surgically documented response to intraperitoneal therapy.
Aged↗
Immunoblot and enzyme-linked immunosorbent assays of Campylobacter major outer-membrane protein and application to the differentiation of Campylobacter species.
The major outer-membrane protein (MOMP) from Campylobacter jejuni NCTC 11168 was purified by solubilization in Triton X-100. Whole-cell proteins of Campylobacter species and the MOMP were subjected to electrophoresis on sodium dodecyl sulfate-polyacrylamide gels, immunoblotting on nitrocellulose paper and enzyme-linked immunoblot assay (ELISA) analyses using polyclonal antiserum to the C. jejuni MOMP. Purified MOMP from C. jejuni NCTC 11168 contained a single major protein of 46 kDa. Whole-cell preparation of C. jejuni NCTC 11168 also showed a major band of 46 kDa which was recognized in immunoblots by the anti-MOMP serum. Other C. jejuni strains, as well as C. coli and C. laridis strains showed similar MOMP bands at 45-46 kDa. Other Campylobacter species (C. fetus ss. fetus, C. hyointestinalis and C. pylori (new nomenclature] did not react in immunoblots with antiserum to the C. jejuni MOMP. ELISAs showed that antiserum raised against the C. jejuni MOMP reacted with C. jejuni, C. coli and C. laridis strains. Other Campylobacter species displayed only a very low degree of cross-reactivity. The distinct antigenic relationship demonstrated between the MOMP of C. jejuni, C. coli and C. laridis is consistent with the close degree of relatedness of these species as determined by DNA homology studies. The anti-MOMP serum appeared to be useful in the rapid differentiation of C. jejuni, C. coli and C. laridis from other Campylobacter species.
Bacterial Outer Membrane Proteins↗
Chimeric antibody with human constant regions and mouse variable regions directed against carcinoma-associated antigen 17-1A.
We have cloned the genomic DNA fragments encoding the heavy and light chain variable regions of monoclonal antibody 17-1A, and we have inserted them into mammalian expression vectors containing genomic DNA segments encoding human gamma 3 and kappa constant regions. The transfer of these expression vectors containing mouse-human chimeric immunoglobulin genes into Sp2/0 mouse myeloma cells resulted in the production of functional IgG that retained the specific binding to the surface antigen 17-1A expressed on colorectal carcinoma cells.
Amino Acid Sequence↗
Instantaneous pressure-volume relation of the ejecting canine left atrium.
To characterize the pump function of the left atrium, we determined the instantaneous pressure-volume relation of the isolated supported left atrium. A physiologic after-loading system for the low-pressure atrium was created by coupling it to a real-time computer-simulated ventricle and a simulated venous impedance network via a volume servo-pump. In 10 atria loaded with such systems, multiple isochronal sets of pressure-volume data were collected from many ejecting or isovolumic contractions obtained under a constant inotropic state, and the time-varying elastance, E(t), as well as the volume-axis intercepts, VO(t), were calculated. E(t) is the ensemble of slopes, and VO(t), the volume-axis intercepts resulting from the linear regression of instantaneous pressure on instantaneous volume at multiple instants throughout the cardiac cycle. The systolic portion of the left atrial E(t) was insensitive to loading conditions, as was VO(t), which, in addition, proved to be similar to the right atrial and right ventricular VO(t) waveforms in its time dependence. These results indicate that E(t) and VO(t) adequately represent the instantaneous pressure-volume relation of the left atrium in systole irrespective of the mode of contraction. Whatever the underlying mechanism might be, the load insensitivity and similarity of the basic shape of the left atrial E(t) among different atria suggests that the characterization reflects fundamental features of left atrial contraction.
Animals↗
Ultrastructure of the pineal gland of the tropical bat Rousettus leschenaulti.
The ultrastructure of the pineal organ was studied in the tropical megachiropteran Rousettus leschenaulti. The pineal lies deep beneath the hemispheres adjacent to the third ventricle and is traversed by the habenular commissure anteriorly. Its parenchyma consists of a uniform population of light and occasional dark pinealocytes which appear to differ only in the degree of cytoplasmic staining. Pinealocytes are characterized by well developed Golgi bodies associated with numerous small vesicles, many mitochondria and polyribosomes, and frequent subsurface cisternae. Lipid droplets and elements of smooth endoplasmic reticulum are scant. Cisternae of granular endoplasmic reticulum are occasionally dilated. A distinct feature is the abundance of clear vesicles in the pinealocyte pericapillary terminals, which also frequently contain granular vesicles and a very large vacuole. The pineal is further characterized by the presence of a small number of glial cells and myelinated nerve fibers. A broad perivascular space investing numerous capillaries contains glial-cell and pinealocyte processes, collagen fibrils and abundant unmyelinated nerve fibers. Tortuous extensions of the perivascular space enter the pineal parenchyma where they come in close proximity to branched intercellular channels or canaliculi characterized by specialized junctions and microvilli. Differences between the pineal of the non-hibernating megachiropteran Rousettus and that of the hibernating microchiropteran bats, and structural similarities to the pineal of tropical rodents are discussed.
Animals↗
Induction and growth of mammary tumors after superior cervical ganglionectomy in sighted and blinded-anosmic rats.
Female rats were subjected to superior cervical ganglionectomy (Gx), blinding and anosmia (BAs) or combined procedures (BAsGx). Onset and growth of dimethylbenz(a)anthracene (DBMA)-induced mammary tumors was studied in these animals and compared to tumorigenesis in intact control rats. Carcinostatic effects were present in all surgically altered animals, as evidenced by a trend toward reduced tumor incidence, reduced final tumor mass, and a significant reduction in mean number of tumors in Gx and BAsGx rats, and increased regression of tumors in BAs rats compared to intact group. Reduced tumorigenesis was paralleled by a trend toward either an increase (BAs) or a decrease (Gx and BAsGx) in the activity of pineal hydroxyindole-O-methyltransferase (HIOMT) compared to intact group. In addition, BAs and BAsGx animals showed a significant reduction in body weight. These results suggest that Gx reduces mammary tumorigenesis in both sighted and BAs rats. They further confirm the findings of others on reduced mammary tumorigenesis in BAs rats. Possible involvement of multiple carcinostatic mechanisms in different animal models is discussed.
9,10-Dimethyl-1,2-benzanthracene↗
Comparison of the effect of bacterial inoculation in musculocutaneous and fasciocutaneous flaps.
The skin fascial flap is now recognized as a reliable flap for use in reconstructive surgery. The fasciocutaneous flap has been advocated for coverage of chronic infected wounds after debridement as an alternative to the musculocutaneous flap. Previous experimental and clinical studies have demonstrated the superior resistance of the musculocutaneous flap as compared to the random-pattern flap to bacterial inoculation. A canine model is presented for comparison of the effect of bacterial inoculation in fasciocutaneous and musculocutaneous flaps of similar dimensions. The area of skin necrosis secondary to bacterial inoculation was similar in these two flap types despite greater blood flow and skin oxygen in the fasciocutaneous flap. In a study of closed wound spaces formed by the deep surface of these two flap types, a greater degree of inhibition and elimination of bacterial growth and more collagen deposition are observed in the musculocutaneous wound space than in the fasciocutaneous flap.
Animals↗
Incidence of antibiotic resistance and characterization of plasmids in Campylobacter jejuni strains isolated from clinical sources in Alberta, Canada.
Antibiotic susceptibilities of 382 strains of Campylobacter jejuni isolated in Alberta, Canada, in 1980 and 1981 were determined. Although none were resistant to erythromycin or gentamicin, 5.4 and 22% of strains were resistant to ampicillin in 1980 and 1981, respectively. Tetracycline resistance was noted in 6.8% of strains in 1980 and in 8.6% in 1981. Moreover, resistance to high-level tetracycline (32-128 micrograms/mL) was always mediated by a plasmid of 45-50 kilobases. Three transmissible plasmids from the Alberta strains were compared with the prototype plasmid pMAK175 by restriction enzyme analysis and some minor differences in restriction sites were noted between pMAK175 and pUA183. The two other plasmids pUA142 and pUA143 were 4 kilobases larger than pMAK175 and contained additional restriction sites. However, in all plasmids examined, the HincII and AccI fragments where the tetracycline-resistance determinant was located were shown to be conserved.
Alberta↗
Chimeric antibodies with 17-1A-derived variable and human constant regions.
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Antibodies, Monoclonal↗
Inhibitory effects of superior cervical ganglionectomy on dimethylbenz(a)anthracene-induced mammary tumors in the rat.
The role of the pineal in regulating the oncogenic processes was explored in Sprague-Dawley female rats by comparing incidence and growth of mammary tumors in animals subjected to superior cervical ganglionectomy (SCGx) or blinding and anosmia (BAs) with that of intact rats treated with 7-12-dimethylbenz(a)anthracene (DMBA). The surgery was performed at the age of 56 days, 1 day following the administration of the carcinogen. Growth of mammary tumors was studied, and 15 weeks later the rats were sacrificed by decapitation and the activity of the pineal hydroxyindole-O-methyltransferase (HIOMT) was determined. Carcinostatic effects of similar magnitude were present in both SCGx and BAs groups as evident from tendency toward reduced tumor incidence and decreased total tumor mass. Ganglionectomized rats developed significantly smaller numbers of tumors than intact control animals. A trend toward reduced tumor number and increased tumor regression was evident in the BAs group. Although there was no significant difference in tumor volumes among the groups, BAs animals showed a distinct trend toward smaller tumor volumes at the termination of the experiment. Despite similar carcinostatic tendencies, SCGx rats had significantly lower HIOMT activity than BAs animals. The possible existence of multiple carcinostatic mechanisms in BAs and SCGx rats is discussed.
9,10-Dimethyl-1,2-benzanthracene↗