Biomedical subjects
C A Hooper
Publications and source records attributed to C A Hooper.
Computer simulations of a tumor surface octapeptide epitope.
Molecular dynamics using CHARMM and GEMM programs with the Star Technologies ST 100 array processor functioning at the speed of super computers was used as a searching algorithm for conformational exploration of the octapeptide Gly-Asn-Thr-Ile-Val-Ala-Glu. This poorly soluble octapeptide is the N-terminal epitope of an 11 KD glycoprotein antigen residing on human ductal carcinoma (breast) cells. Very long (nanoseconds) simulations were required. Both an alpha-helix and the N-acetyl-N1-methylamide derived minimized starting structures gave the same lowest potential energy conformation with simulations at 600 K. The same conformation was found only when using the latter starting conformation with simulations at 300 K. The lowest potential energy conformation was stabilized by 4 hydrophobic contacts and 13 H bonds completing one turn of a left-handed helix.
N-terminal ten amino acid sequence determined for B-cell differentiation factor derived from rabbit breast milk cell supernatant.
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Isolation and characterization of rabbit ileal lamina propria mononuclear cells.
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Rabbit ileal lamina propria (LP) lymphocytes give poor blastogenic responses to KLH immunization and concanavalin A mitogenesis.
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Cefamandole for prophylaxis against infection in closed tube thoracostomy.
During an 18-month period, antibiotic prophylaxis in 120 patients undergoing closed tube thoracostomy was evaluated by a prospective, randomized double-blind technique. Forty-six subjects had sustained penetrating chest trauma. Either placebo (n = 60) or 1 gm/6 hours cefamandole (n = 60) was begun intravenously at the time of tube insertion and was continued intravenously or intramuscularly until the second day following tube removal. Cultures were taken of the pleural drainage, usually blood, at tube insertion, on tube removal, and on several occasions between those times. Antibiotic concentrations were determined biologically on the same specimens of pleural fluid as well as selectively on concomitant venous blood samples. Cultures were also obtained from all subsequent foci of infection, including the wound, any empyema, bronchial secretions, urine, or infected intravenous sites. Aerobic and anaerobic isolation and identification were carried out according to standard laboratory procedures with sensitivity testing (disc and tube dilution) only of the aerobes. Results demonstrated that infection of the lung and/or pleural space was eight times more common in the placebo groups (13.3%) than in the group receiving cefamandole (1.7%) (p less than 0.01). In addition, the single infection that developed despite use of the antibiotic was due to a susceptible organism. No major adverse drug reactions were noted.
Gastrointestinal bleeding due to vitamin K deficiency in patients on parenteral cefamandole.
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Prophylactic and preventive antibiotic therapy: timing, duration and economics.
Previous studies have demonstrated that administered antibiotics must be active against major anticipated pathogens and must have reached sufficient concentrations in the tissue or body fluid at risk by the time of bacterial challenge if prophylactic therapy is to be maximally effective in reducing the infection rate of potentially contaminated surgery. The need for continuing antibiotic prophylaxis beyond the day of operation, however, has been uncertain. In a prospective, randomized, double-blind study of 220 patients undergoing elective gastric, biliary or colonic surgery, perioperative administration of cefamandole plus five days of placebo was compared to perioperative plus five days of postoperative antibiotic therapy; no significant difference was found between the groups in the rate of infection of wound (6 and 5%, respectively), peritoneum (2% each) and elsewhere (6% and 5%). In another prospective, randomized, nonblind study of 451 determinant cases of 1,624 patients undergoing emergency laparotomy, cephalothin was instituted preoperatively but after peritoneal contamination had occurred (i.e., abdominal trauma, etc.); continued postoperative antibiotic again failed to reduce further the wound and peritoneal infection rates, as noted on comparing perioperative therapy alone (infection rates 8 and 4%, respectively) with perioperative plus 5-7 days of postoperative treatment (10% and 5%, respectively). Analysis of these data, as well as of the extra expenses incurred by 463 patients because of infection in a previous prophylactic antibiotic study, revealed an average additional expenditure of $2,686.00 for each instance of postoperative infection of the wound and/or peritoneum; whereas savings of $300.00 per patient at risk were obtained whenever appropriate prophylactic antibiotic had been given.
Abdominal drainage following appendectomy and cholecystectomy.
Consecutive patients undergoing emergency appendectomy (283) or urgent cholecystectomy (51) were prospectively studied for the development of post-operative incisional or peritoneal sepsis. Severity of the original peritoneal infection was carefully recorded, while use of a Penrose dam to drain the peritoneum was randomized according to pre-assigned hospital number. Both aerobic and anaerobic cultures were taken from the abdomen at the time of operation as well as from all postoperative infectious foci. Results demonstrated no essential differences in incidence of wound and peritoneal infection following appendectomy for simple or suppurative appendicitis (187) or following cholecystectomy for acute cholecystitis (51). However, with gangrenous or perforative appendicitis (94), incisional and intra-abdominal infection rates were 43% and 45%, respectively, when a drain was used; yet only 29 and 13%, respectively, without a drain. These latter differences were significant (p < 0.001). In addition, intra-abdominal abscesses were three times as likely to drain through the incision than along any tract provided by the rubber conduit. Cultures revealed that hospital pathogens accounted for a greater proportion of wound and peritoneal sepsis after cholecystectomy and appendectomy for simple or suppurative appendicitis if a drain had been inserted than if managed otherwise. By contrast, a mixed bacterial flora was responsible for most infections following appendectomy for gangrenous or perforated appendicitis, irrespective as to use of a drain.
Antibiotic prophylaxis in gastric, biliary and colonic surgery.
Antibiotic prophylaxis for surgery has appeared indicated whenever likelihood of infection is great or consequences of such are catastrophic. For better clarification, a prospective, randomized, double-blind study was run on 400 patients undergoing elective gastric, biliary, and colonic operations. There were four treatment categories, with antibiotic being instituted 12 hours preoperatively, just prior to operation, after operation, or not at all. During operation, samples of blood, viscera, muscle, and fat were taken for determination of antibiotic concentration. Both aerobic and anareobic cultures were also taken of any viscus entered, peritoneal cavity, and incision. Similar cultures were run on all postoperative infections. Results demonstrated that the incidence of wound infection could be reduced significantly by the preoperative administration of antibiotic in operations on the stomach (22% to 4%), on the biliary tract (11% to 2%), and large bowel (16% to 6%). Less impressive results were obtained for peritoneal sepsis. Initiation of antibiotic postoperatively gave an almost identical infection rate as if antibiotic had not been given (15% and 16%, respectively).