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Biomedical subjects

W Alexander

Publications and source records attributed to W Alexander.

At least 55 records · Page 3Linked to original sources
PubMed1990

Laparoscopic laser cholecystectomy and choledocholithiasis.

The management of common bile duct stones during laparoscopic laser cholecystectomy (LLC) is uncertain. Open common bile duct exploration is the least desirable option since it defeats the purpose of LLC. Endoscopic retrograde cholangiopancreatography (ERCP) with papillotomy has become the procedure of choice since it has a high rate of success and results in minimal morbidity. Intraoperative techniques using balloon catheters and the flexible choledochoscope via the cystic duct may obviate the need for ERCP in selected cases.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1990

Hips while-u-wait. Designing total hips during surgery.

1. There are an infinite number of configurations of the human femur. Individualized implants can now be made through the use of computer-assisted design. 2. Another technique is to pour a quick-setting Silastic molding material directly into the femur during surgery, taking the mold to a laboratory in the hospital, and manufacturing the custom prosthesis in about 45 minutes. 3. These techniques have increased the nurses' responsibilities dramatically, requiring them to handle approximately 17 trays of instruments as well as power and manual tools, and supervising non-physician personnel in the operating room.

Hip Prosthesis↗
PubMed1987

Lack of correlation of slime production with pathogenicity in continuous ambulatory peritoneal dialysis peritonitis caused by coagulase negative staphylococci.

In order to evaluate the association of slime production by coagulase-negative staphylococci (CNS) and pathogenicity in the setting of continuous ambulatory peritoneal dialysis (CAPD), we prospectively studied 23 CAPD patients with positive dialysate cultures for CNS during a 12-mo period. Patients were categorized into groups with peritonitis or contaminants. In addition, 24 skin flora isolates of CNS from nine uninfected CAPD patients were compared to the other two groups. We found 14 patients with peritonitis and nine with contaminants. Fifty percent of the peritonitis isolates produced slime, compared to 67% of the contaminants (p = 0.72) and 54% of the skin flora isolates (p = 0.93). Slime production was not associated with specific antibiotic susceptibility patterns or speciation. In this prospective study, slime production was not associated with pathogenicity in CAPD peritonitis caused by coagulase-negative staphylococci.

Coagulase↗
PubMed1984

Analysis of the pleiotropic regulation of flagellar and chemotaxis gene expression in Caulobacter crescentus by using plasmid complementation.

The biosynthesis of the single polar flagellum and the proteins that comprise the chemotaxis methylation machinery are both temporally and spacially regulated during the Caulobacter crescentus cell-division cycle. The genes involved in these processes are widely separated on the chromosome. The region of the chromosome defined by flaE mutations contains at least one flagellin structural gene and appears to regulate flagellin synthesis and flagellar assembly. The protein product of the adjacent flaY gene was found to be required to regulate the expression of several flagellin proteins and the assembly of a functional flagellum. We demonstrate here that each of these genes is also required for the expression of chemotaxis methylation genes known to map elsewhere on the chromosome. In order to study the regulation of these genes, plasmids were constructed that contain either an intact flaYE region or deletions in the region of flaY. These plasmids were mated into a wild-type strain and into strains containing various Tn5 insertion and deletion mutations and a temperature-sensitive mutation in the flaYE region. The presence of a plasmid containing the flaYE region allowed the mutant strains to swim and to exhibit chemotaxis, to synthesize increased amounts of the flagellins, to methylate their "methyl-accepting chemotaxis proteins" (MCPs), and to regain wild-type levels of methyltransferase activity. Chromosomal deletions that extend beyond the cloned region were not complemented by this plasmid. Plasmids containing small deletions in the flaY region failed to restore to any flaY or flaE mutants the ability to swim or to assemble a flagellar filament. When mated into a wild-type strain, plasmids bearing deletions in the flaY region were found to be recessive. The pleiotropic regulation of flagellin synthesis, assembly, and chemotaxis methylation functions exhibited by both the flaY and flaE genes suggest that their gene products function in a regulatory hierarchy that controls both flagellar and chemotaxis gene expression.

Bacteria↗
PubMed1983

Surgical treatment of recalcitrant warts.

Cryosurgery is the first choice for surgical treatment of viral warts. It is applied in two ways: with blister induction in extraplantar common warts and without blister induction in genital, filiform, and mosaic warts. Plantar and periungual warts are enucleated with a spoon or scraped off with a curet after preparatory focal electrocoagulation with a ball probe. Genital warts may be treated with "extracutaneous" electrosection and electrocoagulation.

Cryosurgery↗
PubMedDate not supplied

Absence of factors associated with significant urinary tract infections caused by coagulase-negative staphylococci.

Coagulase-negative staphylococci, excluding Staphylococcus saprophyticus, have recently been implicated as pathogens in urinary tract infections, especially in catheterized patients. In order to evaluate any laboratory markers for significant isolates of coagulase-negative staphylococci, we prospectively studied 72 patients with significant, indeterminant, or contaminant urine isolates of coagulase-negative staphylococci. Patients in the three categories did not differ by age, sex, presence of a urinary catheter, or other instrumentation or likelihood of nosocomial acquisition. The isolates from these three groups of patients were similar in antibiotic susceptibility and ability to produce slime. Overall, slime-producing coagulase-negative staphylococci were more likely to be S. epidermidis than any other species, but slime production was not associated with presence of pyuria, symptomatic urinary tract infection, instrumentation, nosocomial acquisition, or multiple antibiotic resistance. In this prospective study, no demographic characteristics or laboratory markers of coagulase-negative staphylococci were associated with clinical significance, as defined by symptoms or the presence of pyuria.

Bacteriuria↗
PubMedDate not supplied

Airborne aldehydes from heating rosin core solder and liquid rosin flux to soldering temperatures.

Gas phase aldehydes produced from heating rosin core solder and liquid rosin flux to temperatures commonly used in soldering were trapped on sampling tubes containing XAD-2 resin coated with the derivatizing agent 2-hydroxymethylpiperidine. Analysis of the resulting oxazolidine derivatives was performed using gas chromatography/mass spectrometry (GC/MS). The observed aldehyde derivatives included formaldehyde, acetaldehyde, propionaldehyde, acrolein, isobutyraldehyde, butyraldehyde, isovaleraldehyde, valeraldehyde, furfural, hexanal, cyclohexane carboxaldehyde and other unidentified compounds likely to be aldehyde isomers. Formaldehyde, acetaldehyde, and benzaldehyde were detected in blank samples. By comparison with an internal standard, a sample produced by drawing air with contaminants derived by heating rosin core solder through a sampling tube contained levels of formaldehyde and acetaldehyde much greater than seen in sampling tube blanks. Benzaldehyde was not shown to be present at a significantly greater level in samples from heating rosin core solder than in blanks prepared using the same analysis protocol. The use of National Institute of Occupational Safety and Health (NIOSH) method 2539 extraction procedures produced blanks with levels of formaldehyde significantly lower than with a modified extraction method (methylene chloride, no sonication). The modified extraction method produced significantly lower benzaldehyde levels in blanks compared with the NIOSH extraction method using toluene and sonication of sampling sorbent tubes.

Air Pollutants, Occupational↗