Biomedical subjects

C C Kuo

Publications and source records attributed to C C Kuo.

At least 145 records · Page 8Linked to original sources

PubMed1992

Chronic Chlamydia trachomatis infections in infants.

OBJECTIVE: --To study the natural history of Chlamydia trachomatis infections in infants. DESIGN: --Bacteriologic and serologic study of an inception cohort. SETTING: --University of Washington Medical Center, Seattle. PARTICIPANTS: --Twenty-two infants with C trachomatis infections either not treated early in life or recurring after antimicrobial treatment. MAIN OUTCOME MEASURES: --Persistence of infection in various anatomic sites, antibody responses to specific serovars (serologic variants) of C trachomatis, and serovars of isolates from mothers and infants. RESULTS: --The cumulative proportion of infants still infected at the age of 1 year was 35%. Infection persisted in the conjunctiva, nasopharynx, and oropharynx in one child for as long as 866 days (28.5 months), when she was cured by treatment. In none of the infants did serologic tests suggest acquisition of infection other than at birth. Isolates of C trachomatis from mothers and their respective infants were always of the same serovar. CONCLUSIONS: --Many infants infected with C trachomatis at birth remain infected for months or years in the absence of specific antimicrobial therapy. Such infections may be confused with those acquired by sexual abuse.

Antibodies, Bacterial↗

PubMed1992

Accumulation of a Brazil nut albumin in seeds of transgenic canola results in enhanced levels of seed protein methionine.

We have increased the methionine content of the seed proteins of a commercial winter variety of canola by expressing a chimeric gene encoding a methionine-rich seed protein from Brazil nut in the seeds of transgenic plants. Transgenic canola seeds accumulate the heterologous methionine-rich protein at levels which range from 1.7% to 4.0% of the total seed protein and contain up to 33% more methionine. The precursor of the methionine-rich protein is processed correctly in the seeds, resulting in the appearance of the mature protein in the 2S protein fraction. The 2S methionine-rich protein accumulates in the transgenic seeds at the same time in development as the canola 11S seed proteins and disappears rapidly upon germination of the seed. The increase in methionine in the canola seed proteins should increase the value of canola meal which is used in animal feed formulations.

Gene Expression↗

PubMed1992

A functional view of the entrances of L-type Ca2+ channels: estimates of the size and surface potential at the pore mouths.

At extreme membrane potentials, the unitary inward and outward currents through L-type Ca2+ channels become diffusion controlled and saturate. The magnitudes of these currents indicate that the pore entrances are asymmetric, with the external mouth being much larger than the internal one. On the other hand, negative surface potentials at the two ends of the pore are rather similar. Both would be significant only when the ambient ionic strength is 110 mM or less. We conclude that the surface charges will not help much in concentrating the channel's favorite divalent cations in the physiological condition. However, the pore does possess an external mouth large enough to make the important inward Ca2+ flow not limited by diffusion, even with only 1 mM external Ca2+.

Animals↗

PubMed1992

In vitro activity of nonoxynol 9 on HeLa 229 cells and primary monkey cervical epithelial cells infected with Chlamydia trachomatis.

Nonoxynol 9 (non-9) is the active ingredient in a wide variety of vaginal contraceptive preparations. The manufacturer recommendation for optimal contraceptive practice is repeated application every 6 h. We studied the in vitro activity of non-9 against Chlamydia trachomatis (E/UW-5/Cx) and its toxicity against HeLa 229 cells and monkey cervical epithelial cells. With a contact time of 6 h, non-9 was toxic to HeLa cells at concentrations of 50 micrograms/ml or greater and to monkey cervical cells at 100 micrograms/ml or greater. Inhibitory effects of non-9 on extracellular chlamydiae were observed at concentrations of 50 micrograms/ml or greater. Inhibition of intracellular growth of chlamydiae in monkey cervical cells was observed at a nontoxic concentration of 50 micrograms/ml. Our studies show that non-9 has antichlamydial activity. However, owing to its toxicity to cervical cells in vitro, the effects of prolonged use of non-9 in vivo should be further studied.

Animals↗

PubMed1992

Effects of ascorbic acid on Chlamydia trachomatis infection and on erythromycin treatment in primary cultures of human amniotic cells.

Ascorbic acid (vitamin C) is an essential nutrient for humans. It may also be needed by Chlamydia trachomatis, an intracellular bacterium. We investigated the effects of vitamin C on the growth of C. trachomatis E/UW-5/Cx in a primary culture of human amniotic epithelial cells. The results showed that vitamin C enhances C. trachomatis infection at concentrations of 0.2, 0.6, and 1.2 mg/dl (P less than 0.001). These three concentrations represent the in vivo concentrations of deficiency, normal, and overload levels in serum, respectively. The enhancement was dose dependent. However, the growth of C. trachomatis was inhibited at vitamin C concentrations of 120 and 1,200 mg/dl. The inhibitory effect of erythromycin against C. trachomatis was shown to be reduced in the presence of vitamin C at the three concentrations tested (P less than 0.025-0.001), and MICs were four times greater (1.6 versus 0.4 micrograms/ml). Human amniotic cells were tolerant to vitamin C concentrations of up to 1,200 mg/dl. The results show that vitamin C may be an important nutrient for C. trachomatis and that incorporation of vitamin C in the culture medium may enhance the isolation and propagation of C. trachomatis in cell cultures.

Amnion↗

PubMed1992

Detection of Chlamydia pneumoniae by polymerase chain reaction.

While criteria for serodiagnosis of Chlamydia pneumoniae infection are well established, isolation of the organism is often difficult. To increase detection of this organism, C. pneumoniae-specific sequences were identified to permit amplification of C. pneumoniae by polymerase chain reaction (PCR). A cloned C. pneumoniae 474-bp PstI fragment was shown by dot blot and Southern hybridization to differentiate C. pneumoniae from the other Chlamydia spp., react with all C. pneumoniae isolates tested, and not recognize DNA from normal throat flora or common respiratory tract agents. This cloned fragment was sequenced and primers for use in PCR were chosen on the bases of GenBank analysis, G + C ratio, and absence of secondary structure. All C. pneumoniae isolates tested were amplified by the HL-1-HR-1 primer pair or the HM-1-HR-1 primer pair, producing the expected 437- and 229-bp amplification products, respectively. None of the Chlamydia trachomatis serovars (B/TW-5/OT, C/TW-3/OT, D/UW-3/Cx, E/UW-5/Cx, F/UW-6/Cx, H/UW-4/Cx, I/UW-12/Ur, and L2/434/Bu), Chlamydia psittaci strains (Mn, 6BC, GPIC, FP, and OA), HeLa cells, or other organisms tested were amplified. Reaction conditions including MgCl2, oligonucleotides, and primer concentrations and temperature were optimized before application to clinical samples. Clinical specimens from patients from whom C. pneumoniae was isolated were also positive by PCR, while samples from patients with known C. trachomatis or C. psittaci infection were not amplified by PCR.

Base Sequence↗

PubMed1992

Detection of Chlamydia pneumoniae in coronary arterial fatty streaks and atheromatous plaques.

There is serological evidence that a recently described new strain of Chlamydia, namely Chlamydia pneumoniae TWAR, is associated with coronary artery disease. This study describes the detection of TWAR organisms in the coronary arterial fatty streaks and atheromatous plaques in 7 autopsy cases. TWAR-like organisms were observed ultrastructurally in the lipid-rich core area of fibrolipid plaques and in intimal smooth-muscle cells. In 5 cases, immunoperoxidase staining showed positive reactions to Chlamydia genus- and C. pneumoniae species-specific monoclonal antibodies.

Adult↗

PubMed1991

The characterization of lectin-binding proteins of Chlamydia trachomatis as glycoproteins.

The 18 kDa and 32 kDa lectin binding proteins of Chlamydia trachomatis were characterized as glycoproteins by treatments with glycosidases. The proteins of the serovar L2 whole cell lysate were separated by SDS-PAGE and transferred to nitrocellulose paper. After treatment with an enzyme, the proteins were reacted with a biotinylated lectin. Each of the endoglycosidases tested affected the binding of the lectin to the protein. PNGase F inhibited the binding of Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), and Ulex europaeus agglutinin I (UEAI) to both the 18 kDa and 32 kDa proteins. Endoglycosidase F and H inhibited the binding of these lectins to the 32 kDa protein completely and to the 18 kDa protein partially. In the exoglycosidase treatments, alpha-L-fucosidase prevented binding of only UEAI to the two proteins while beta-galactosidase inhibited the binding of SBA. Mannosidase abolished the binding of all the lectins tested. Neuraminidase had no effect. The proteins isolated by electroelution from the excised gels after SDS-PAGE were digested with an endoglycosidase. PNGase F-treated proteins showed a lower molecular weight mobility in which the lectin binding ability was destroyed. Endo-alpha-N-acetylgalactosaminidase had no effect. The polysaccharide stain of isolated proteins with p-phenylenediamine showed a positive reaction. Radiolabeling with [3H]glucosamine did not reveal the 18 kDa and 32 kDa proteins in autoradiography but [3H]galactose did.

Bacterial Adhesion↗

PubMed1991

Isolation and sequence analysis of the Chlamydia pneumoniae GroE operon.

Chlamydia pneumoniae has emerged as an important human respiratory pathogen. From a lambda gt11 gene bank constructed from C. pneumoniae isolate AR-39 DNA, an immunoreactive plaque containing a 3.0-kb insert was purified. In immunoblots, a 60-kDa protein was recognized by anti-C. pneumoniae rabbit immune serum. The recombinant protein was reactive with a Chlamydia genus-specific monoclonal antibody recognizing a 60-kDa protein found in the Sarkosyl-soluble fraction and with rabbit immune serum prepared against the Chlamydia trachomatis 60-kDa GroEL homolog associated with the delayed-type hypersensitivity response. DNA sequence analysis confirmed that the C. pneumoniae gene product is an analog of the C. trachomatis delayed-type hypersensitivity antigen and the Escherichia coli GroEL heat shock protein.

Amino Acid Sequence↗

PubMed1991

Sequence analysis of the gene encoding the Chlamydia pneumoniae DnaK protein homolog.

The antigen-coding region of a 4.2-kb PstI fragment of Chlamydia pneumoniae (pLC3), which encodes a 75-kDa immunoreactive protein recognized during human C. pneumoniae infection, was localized to a 2.0-kb EcoRI fragment. This subclone expressed an immunoreactive fusion protein of ca. 82 kDa. Nucleotide sequence analysis of the C. pneumoniae gene revealed that it consisted of a 1,980-base open reading frame with an inferred 71,550-Da protein of 660 amino acids. Putative Escherichia coli-like promoters and a ribosomal binding site were located in the 5' upstream region, and an 11-base dyad forming a stable stem-loop structure following two in-frame stop codons was identified. The C. pneumoniae 75-kDa protein is a member of the hsp70 family of heat shock proteins and has 87% amino acid similarity with the Chlamydia trachomatis protein.

Amino Acid Sequence↗

PubMed1991

Evidence that the major outer membrane protein of Chlamydia trachomatis is glycosylated.

The major outer membrane protein (MOMP) of Chlamydia trachomatis was determined to be a glycoprotein on the basis of susceptibility to glycosidase digestion and the presence of carbohydrate by staining and radiolabeling. The MOMP of the serovar L2 organisms was isolated by electroelution from the protein band excised from the gel after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The incubation of MOMP with N-glycosidase F, an endoglycosidase that cleaves the N-glycan, and periodate resulted in two new molecular weight species. While MOMP treated with N-glycosidase F showed a lower-molecular-weight mobility, the periodate-treated MOMP increased in molecular weight. Both treatments abolished the ability of the MOMP to bind to HeLa cell components. In the immunoblot, the reactivity to the monoclonal antibody specific against the C. trachomatis species was preserved. The endoglycosidase specific to O-linked glycan, endo-alpha-N-acetylgalactosaminidase, had no visible effect on the isolated MOMP. Carbohydrate was detected in the MOMP by p-phenylenediamine staining of the protein band in the gel following SDS-PAGE. Autoradiograms of proteins of chlamydial organisms metabolically labeled with [3H]galactose or [3H]glucosamine and separated by SDS-PAGE revealed the MOMP band. The isolated MOMP was shown to bind specifically to concanavalin A, wheat germ agglutinin, and Dolichos biflorus agglutinin in the lectin binding assay. No binding was observed with Ulex europaeus agglutinin I, soybean agglutinin, or Ricinus communis agglutinin.

Animals↗

PubMed1991

Sequence analysis of the major outer membrane protein gene of Chlamydia pneumoniae.

Compared with the major outer membrane proteins (MOMPs) of the other chlamydial species, the Chlamydia pneumoniae MOMP appears to be less antigenically complex, and as determined by immunoblot analysis, it does not appear to be the immunodominant antigen recognized during infection. Nucleotide sequence analysis of the C. pneumoniae MOMP gene (ompA) revealed that it consisted of a 1,167-base open reading frame with an inferred 39,344-dalton mature protein of 366 amino acids plus a 23-amino-acid leader sequence. A ribosomal-binding site was located in the 5' upstream region, and two stop codons followed by an 11-base dyad forming a stable stem-loop structure were identified. This sequence shares 68 and 71% DNA sequence homology to the Chlamydia trachomatis serovar L2 and Chlamydia psittaci ovine abortion agent MOMP genes, respectively. Interspecies alignment identified regions, corresponding to the variable domains, which share little sequence similarity with the other chlamydial MOMPs. All seven cysteines conserved in the C. trachomatis and C. psittaci MOMPs, which are involved in the formation of disulfide cross-linkages, are found in the C. pneumoniae MOMP.

Amino Acid Sequence↗

PubMed1991

Chlamydia pneumoniae, strain TWAR, infection in patients with chronic obstructive pulmonary disease.

TWAR, the only known serovar of Chlamydia pneumoniae, is a newly described bacterium that has been identified as a cause of both epidemics and endemic cases of pneumonia. The role of TWAR infection in patients with chronic obstructive pulmonary disease (COPD) is not known. We conducted a prospective study to establish whether TWAR infection is a common cause of acute exacerbations of COPD. We studied two groups of patients: 44 patients admitted to the hospital with acute exacerbations of COPD, and 65 stable clinic patients with COPD. We found that evidence of acute TWAR infection was infrequent in patients with exacerbations (5%). In contrast, the majority of patients from both groups had serologic evidence of previous TWAR infection (77%). This was not significantly greater than the prevalence found in a small group of patients of similar age and sex without lung disease from the same institution (73%). TWAR was not isolated from the oropharyngeal specimens obtained from 97 subjects, suggesting that it does not colonize the respiratory tract of patients with COPD. This study shows that at the time of low incidence in the community, acute TWAR infection is uncommon in patients with acute exacerbations of COPD. The majority of patients with COPD have, however, been infected with TWAR in the past. The clinical manifestations of these infections are not known and should be the focus of further studies.

Aged↗

PubMed1990

Ofloxacin treatment of Chlamydia pneumoniae (strain TWAR) lower respiratory tract infections.

PURPOSE: Limited data suggest that tetracycline or erythromycin is the antibiotic of choice for treating Chlamydia pneumoniae infection, but they are not always effective or well tolerated. Because the fluoroquinolone ofloxacin is effective for Chlamydia trachomatis infections, we investigated its role in treating C. pneumoniae infections. PATIENTS AND METHODS: Eighty-seven patients were enrolled in a randomized trial of antibiotic therapy for acute lower respiratory tract infections. The patients were randomly assigned to oral treatment with either ofloxacin (400 mg twice a day) or erythromycin (400 mg four times a day) for 10 days. Frozen acute and convalescent serologic specimens were tested for TWAR antibody by microimmunofluorescence. Susceptibility testing of C. pneumoniae to ofloxacin was also performed. RESULTS: Four patients who received ofloxacin were retrospectively identified as having C. pneumoniae pneumonia (two) or bronchitis (two). Within 2 weeks of starting ofloxacin therapy, all were cured or markedly improved. The minimum inhibitory concentrations of ofloxacin for three previously isolated clinical strains of C. pneumoniae were determined to be 1.0 to 2.0 micrograms/mL, well within the achievable serum levels (3 to 5 micrograms/mL) with ofloxacin therapy. CONCLUSION: Ofloxacin may be an effective alternative antibiotic treatment for C. pneumoniae respiratory infections.

Aged↗

PubMed1990

A new respiratory tract pathogen: Chlamydia pneumoniae strain TWAR.

Chlamydia pneumoniae strain TWAR, the new third species of Chlamydia, is a common cause of pneumonia and other acute respiratory tract infections. About 10% of hospitalized and outpatient pneumonia cases have been associated with TWAR infection. TWAR is among the four or five most commonly identified causes of all pneumonia. Most TWAR infections are mild or asymptomatic, but occasionally severe pneumonia with death has been observed. Laboratory diagnosis is not generally available. Vigorous treatment with tetracycline or erythromycin is recommended. Both epidemic and endemic infections have been described in North America and the Nordic Countries. Population prevalence antibody studies suggest that TWAR infection is wide-spread throughout the world, that nearly everyone is infected and reinfected during their life-time, and that infection is common in all ages except those less than 5 years in temperate zone countries. The infection is transmitted from person to person, apparently with a long incubation period.

Chlamydia↗

PubMed1990

A sensitive cell line, HL cells, for isolation and propagation of Chlamydia pneumoniae strain TWAR.

The sensitivity of a human line, HL cells, for growth of Chlamydia pneumonia was compared with HeLa 229 cells using laboratory-adapted and wild strains. HL cells were more sensitive for growth of HeLa-adapted C. pneumoniae strains and more sensitive for isolation of the organism from patient specimens. Adaptation of new isolates to continuous cell culture growth has been much more successful in HL cells. Centrifugation of inoculum and incorporation of cycloheximide in the medium enhanced the infectivity. Microscopic observation of cultures from days 2 to 6 showed that C. pneumoniae undergoes a second cycle of growth in HL cells. However, the optimal time of harvesting is 3 days after inoculation.

Cell Line↗

PubMed1990

Transmission of Chlamydia pneumoniae in young children in a Japanese family.

Chlamydia pneumoniae strain TWAR was isolated from the respiratory tract of a 5-year-old girl suffering from pneumonia. The IgM and IgG antibody titers to TWAR were 1:32 and 1:128, respectively. Cultures and serology for other common bacterial and viral respiratory pathogens were negative. Although she was treated with 35 mg/kg/day rokitamycin, TWAR was repeatedly isolated after treatment. Her 3-year-old sister developed acute bronchitis, and TWAR was isolated from her nasopharynx. She was treated with 43 mg/kg/day erythromycin with prompt improvement, and TWAR was not isolated after treatment. Although her mother, grandmother, and 8-month-old sister suffered from respiratory illness during these periods, TWAR was not isolated from them. The repeated isolations from the index patient suggest that infection was transmitted from sister to sister. This case represents the first reported isolation of TWAR from young children in the same household and the first from Japan.

Adult↗

PubMed1990

Chlamydia pneumoniae strain TWAR, Mycoplasma pneumoniae, and viral infections in acute respiratory disease in a university student health clinic population.

Clinical and serologic data were collected on 667 University of Washington students who presented to the David Hall Student Health Center between 1983 and 1987 with acute respiratory disease. Sera were tested for evidence of acute or past infections with Chlamydia pneumoniae strain TWAR, Chlamydia trachomatis, Mycoplasma pneumoniae, influenza A virus, influenza B virus, adenovirus, and respiratory syncytial virus. Pharyngeal swab specimens were cultured for C. pneumoniae and C. trachomatis, but not for the other agents. Evidence of acute infection with C. pneumoniae was found in 20 patients and evidence of an acute infection with M. pneumoniae in 29 patients. C. pneumoniae was associated with 9% and M. pneumoniae with 11% of 149 pneumonias diagnosed clinically, and with 20% and 22%, respectively, of the 59 pneumonias confirmed on chest radiograph. There was no evidence of seasonality in C. pneumoniae or M. pneumoniae infections. Compared with patients with M. pneumoniae, patients with C. pneumoniae were less likely to have a temperature greater than 37.8 degrees C (10% vs. 34%), but were more likely to present with a sore throat (80% vs. 52%) or hoarseness (30% vs. 3%). The mean number of days from onset of symptoms until enrollment was longer in patients with C. pneumoniae infections than in those with M. pneumoniae (12.8 vs. 7.9 days), or those with a viral infection (12.8 vs. 7.3 days), suggesting a more gradual onset of disease caused by C. pneumoniae.

Adolescent↗