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Biomedical subjects

K Borchardt

Publications and source records attributed to K Borchardt.

10 recordsLinked to original sources
PubMed2001

Genomic structure, developmental distribution and functional properties of the chicken P2X(5) receptor.

We report here the cloning of a chicken cDNA (402 aa) showing high sequence similarity to the previously cloned rat and human P2X(5) receptors (67 and 69%, respectively). The chicken P2X(5) subunit is encoded by a gene composed of 12 translated exons, which shows conserved genomic structure with mammalian P2X genes. In HEK-293 cells heterologously expressing chicken P2X(5) receptors, ATP activates a current that desensitizes in a way that is dependent on the presence of extracellular divalent cations. ATP and 2-methylthio ATP are equipotent agonists (EC(50) approximately 2 microM) and suramin and pyridoxal 5-phosphate-6-azophenyl-2',4'-disulfonic acid are potent antagonists. Additionally, reversal potential measurements indicate that chicken P2X(5) is permeable not only to cations but also to chloride (P(Cs+)/P(Cl-) approximately 1.9), as has been described for native P2X receptor mediated responses in embryonic chicken skeletal muscle. mRNA distribution of chicken P2X(5) was determined by in situ hybridization analysis in both whole embryos and on tissue slices of heart and skeletal muscle. Our results suggest that chicken P2X(5) receptors are expressed in developing muscle and might play a role in early muscle differentiation.

Amino Acid Sequence↗
PubMed1993

Detection of Trichomonas vaginalis in pregnant women with the InPouch TV culture system.

Trichomonas vaginalis causes a common genitourinary infection which is frequently asymptomatic. At present, pregnant women are not usually screened for the infection unless they are symptomatic. In the present study, we screened and obtained samples for culture from all pregnant women attending a prenatal clinic with the InPouch TV culture system and compared results with those of standard culture in Diamond's medium and slide wet mount examination. The InPouch TV culture system was as reliable as Diamond's medium in detecting T. vaginalis and may be useful and effective in a pregnancy clinic setting.

Animals↗
PubMed1991

The ability of cationic amphiphilic compounds to depress the transition temperature of dipalmitoylphosphatidic acid liposomes depends on the spatial arrangement of the lipophilic moiety.

The hypothesis was tested with the help of model compounds that the ability of cationic amphiphilic drugs to depress the phase-transition temperature Tt of dipalmitoylphosphatidic acid (DPPA) liposomes depends on the spatial arrangement of the lipophilic moiety. The main structure of the compounds with identical cationic side chain was 1-dimethylamino-3-phenylpropane (compound I). A further phenyl ring was introduced either at C3 of the propane chain (compound II) to broaden the lipophilic moiety, or in para-position of the phenyl ring (compound III) to elongate it. As shown by differential scanning calorimetry, the reduction of Tt (control 64 degrees) amounted for compound I to 29 degrees, for compound II to 28 degrees and for compound III to 53 degrees. In order to assess the binding affinity of the compounds to DPPA, their inhibitory effect on 45Ca(2+)-binding to DPPA films was measured. The IC50 values were 2100 microM for compound I, 40 microM for compound II, and 9 microM for compound III. Thus, binding affinity corresponded with the hydrophobicity of the compounds. In contrast, the depressing effect on the transition temperature was only augmented by the additional phenyl ring when substituted in the elongating position.

Calcium↗
PubMed1990

The limited value of symptoms and signs in the diagnosis of vaginal infections.

The etiology of vaginitis can be difficult to prove. To determine the relationship between clinical criteria (symptoms and signs) and three causes of vaginitis, we prospectively evaluated 22 criteria in 123 unselected symptomatic patients. Diagnoses of Candida albicans and Trichomonas vaginalis infection were based on culture. Bacterial vaginosis was defined by the presence of 3 of 4 clinical criteria. Only 49% of our patients received diagnoses, and itching was the only symptom more frequently noted among those with diagnoses. Symptoms did not differ among the three infections, and lack of vaginal odor in yeast infection was the only significantly different physical sign. Yeast and trichomonads were seen on microscopy in 63% and 75% of culture-positive specimens. Bacterial vaginosis had no significant clinical criteria beyond those that defined the diagnosis. We conclude that presenting symptoms and signs in vaginitis evaluation have limited value, and that half of the women with vaginitis may lack a microbiologic diagnosis.

Adult↗
PubMed1978

Stability of antimicrobials in Schaedler's anaerobic and brain heart infusion broths stored at --20 degrees C.

Penicillin-like drugs are found to be unstable in SCHAEDLER'S broth in forzen storage (--20 degrees C). Chloramphenicol, clindamycin and tetracycline remained at original potency to 45 days. No detectable antimicrobial decay was found in two formulations of supplemented BHI broth. Antimicrobial potency was measured by quality control organism endpoints, bioassays and MIC changes in use at four clinical microbiology laboratories.

Anaerobiosis↗