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Biomedical subjects

C D Knight

Publications and source records attributed to C D Knight.

49 records · Page 3Linked to original sources
PubMed1984

Conversion of 2-hydroxy-4-(methylthio)butanoic acid to L-methionine in the chick: a stereospecific pathway.

Conversion of 2-hydroxy-4-(methylthio)butanoic acid (HMB) to L-methionine (L-Met) was studied by using chick liver homogenates. The first step was found to be stereospecific with different enzymes for the D- and L-isomers of HMB. L-HMB was the substrate for L-2-hydroxy acid oxidase, a peroxide-producing flavo-enzyme found in peroxisomes of liver and kidney. The enzyme for D-HMB, identified as mitochondrial D-2-hydroxy acid dehydrogenase, had not been previously described in the chick. This enzyme was found in every tissue tested including intestinal mucosa and skeletal muscle. Thus, D-HMB could be used by any organ for protein synthesis, like L-Met itself. These results provide a biochemical explanation of equimolar incorporation of HMB and DL-methionine (DL-Met) into chick hepatocyte protein in that the two HMB enzymes can simultaneously convert both HMB isomers to L-Met while only one enzyme, D-2-amino acid oxidase, converts D-Met to L-Met.

Acetamides↗
PubMed1984

The effects of intestinal Escherichia coli 263, intravenous infusion of Escherichia coli 263 culture filtrate and iron dextran supplementation on iron metabolism in the young pig.

An experiment using 32 pigs in a 2(3) factorial arrangement of treatments was used to determine the effects on the (1) level of iron dextran supplementation, (2) iv infusion of an Escherichia coli 263 culture filtrate and (3) presence of E. coli 263 in a ligated intestinal segment, on the ability of the young pig to limit systemic Fe availability. Iron dextran was administered im 3 d postpartum. Culture filtrate was infused iv, E. coli were injected into ligated intestines and blood sampling was started at 14 d postpartum. Blood was taken every 2 h for 22 h, after which pigs were euthanized and livers, spleens and kidneys were removed. Pigs receiving 400 mg of iron dextran (HiFe) exhibited greater serum Fe (SFe) and lower total Fe-binding capacity (TIBC) than pigs injected with 100 mg Fe (LoFe). The effects of the E. coli culture filtrate infusion appeared to be associated with endotoxin-induced circulatory shock. The presence of E. coli in the intestine increased TIBC in LoFe pigs, but not in HiFe pigs. The increase in TIBC coincided with the time of maximal fluid secretion into the intestine. Intestinal E. coli also caused an increase in liver Fe content, particularly in HiFe pigs. These data suggest that intestinal E. coli can cause a shift of Fe from the plasma to the reticuloendothelial system, and pigs receiving high supplemental dosages of Fe are less able to limit the availability of Fe to microorganisms.

Animals↗
PubMed1983

Abdominal wound closure with a continuous monofilament polypropylene suture. Experience with 1,000 consecutive cases.

We report our experience with 1,000 consecutive abdominal wound closures using continuous monofilament polypropylene (Prolene) sutures. Wound dehiscence occurred in four patients (0.4%), and incisional hernia occurred in seven patients (0.7%). The incidence of persistent suture sinus was less than 1%. A comparison of these results with the reported data showed that this method was at least equal to other types of wound closure. While the polypropylene suture is more difficult to handle than traditional sutures, it is probably the preferred suture for contaminated and dirty wounds. It has eliminated the need for retention sutures in our practice, and its use as a continuous, running closure has offered the advantage over the usual interrupted technique of being simpler, faster, and more cost effective. Sepsis has continued to be the greatest cause of failure of abdominal wounds to heal.

Abdomen↗
PubMed1983

Cloning of the symbiotic region of Rhizobium leguminosarum: the nodulation genes are between the nitrogenase genes and a nifA-like gene.

The region of the Rhizobium leguminosarum plasmid pRL1JI involved in nodulation and nitrogen fixation has been cloned on a series of four overlapping cosmid clones. These clones represent 60 kb of pRL1JI DNA on which a series of Tn5-induced fix and nod alleles have been identified, with the two most distant alleles being separated by 45 kb of DNA. The mutant alleles fell into three groups, two clusters of fix alleles separated by one cluster of nod alleles. Within one group of fix alleles, DNA homologous to the nifA gene of Klebsiella pneumoniae has been identified, whereas the pRL1JI DNA homologous to the K. pneumoniae nitrogenase genes is present within the other group of fix alleles.

Journal Article↗
PubMed1983

Proximal gastric vagotomy: update.

Experience with proximal gastric vagotomy at the Mayo Clinic from 1973 to Mayo 1980 is reported. Among 298 patients who had proximal gastric vagotomy for chronic duodenal, pyloric channel, or prepyloric ulcers, a recurrent ulcer rate of 7% was present, with a mean follow-up of 49 months. Three recurrences developed in six patients who had proximal gastric vagotomy for gastric ulceration. In 40 patients, proximal gastric vagotomy was combined with gastrojejunostomy, pyloroplasty, or pyloric dilatation for obstructing ulcers. There was a 15% incidence of reoperation in the gastrojejunostomy group. All nine patients who had proximal gastric vagotomy for active or recent bleeding ulcers were dismissed from the hospital without further hemorrhage, and only one developed a recurrent ulcer. It is concluded that proximal gastric vagotomy remains an acceptable operation for chronic duodenal and pyloric ulcers, but its efficacy in gastric ulcers is unproved.

Female↗
PubMed1983

Treatment of aortic graft infection with providone-iodine irrigation.

Considerable morbidity and mortality are associated with infections of vascular prosthetic grafts. Most vascular surgeons believe that once vascular prosthetic graft infections occur, any form of therapy short of removal of the prosthesis will fail. Although recent reports have noted the successful conservative treatment of vascular prosthetic graft infections in the groin, most surgeons have been hesitant to use such therapy for aortic prosthetic graft infections. We describe an 88-year-old woman with an aortic graft infection 2 months after abdominal aortic aneurysmectomy who was treated successfully with local debridement and continuous irrigation of the graft bed with providone-iodine solution. Such local therapy is an alternative and sometimes effective method of managing patients with infected aortic grafts in whom the risk of resection of the prosthesis and revascularization would be prohibitive.

Aged↗
PubMed1980

Effects of iron on the anti-coli capacity of sow's milk in vitro and in ligated intestinal segments.

The effect of iron on the ability of sow's milk to suppress Escherichia coli was examined both in vitro and in ligated intestinal segments of neonatal pigs. Sow's milk from day 7 of lactation was diluted with NaHCO3/KH2PO4 and divided into four treatment groups: (1) diluted milk; (2) diluted milk + ferric citrate; (3) diluted milk heated at 100 degrees for 20 minutes, and (4) treatment 3 + ferric citrate. Treatment groups were tested for antibacterial activity in vitro after inoculation of 10(4) Escherichia coli (strain 263); counts after a 3-hour incubation were: 721, 9,290, 11,400 and 9,680 for treatments 1-4, respectively. The same four treatments were tested in ligated intestinal segments of 9-day-old pigs with or without the addition of 10(4) E. coli. The average total E. coli count (+10(5)) per centimeter of intestine for 16 pigs after 3 hours of incubation were: 11, 50, 84 and 249 for treatments 1-4, respectively, without additional E. coli and 14, 110, 314 and 535 with additional E. coli. The effects of exogenous iron on the in vitro anti-coli capacity of sow's milk were also examined at 3-day intervals throughout the first 21 days of lactation. Iron had a significant detrimental effect on the anti-coli capacity of sow's milk from days 6 to 18 of lactation. Iron did not have an effect on the anti-coli capacity of colostrum, which exhibited bactericidal activity, or on milk from the 21st day of lactation, which allowed good E. coli growth. Results from these studies suggest that iron reduces the capacity of sow's milk to repress E. coli concentrations both in vitro and in vivo.

Animals↗
PubMed1980

An improved technique for low anterior resection of the rectum using the EEA stapler.

The technique using the EEA stapler for low anterior resection of the rectum has been modified to permit a low anastomosis that can be done with greater facility and safety. The method eliminates the bulky puckering of the ampullary purse string and avoids the disadvantage of joining segments of bowel of different sizes. It also decreases intraoperative contamination and minimizes chances for sepsis. Additionally, it affords an opportunity to check the integrity of the anastomosis. Success of the method seems to document the safety of stapling across a staple line. Results of this method used in a small group of patients are encouraging.

Humans↗
PubMedDate not supplied

Results of the double stapling procedure in pelvic surgery.

The double stapling technique for rectal reconstruction after resection involves closing the lower rectal segment with a linear stapler and performing the anastomosis using a circular stapler across the linear staple row. The purpose of this report is to review the results of double stapling, present our experience, and draw conclusions from the material available. We have utilized the double stapling technique in 80 patients for primary anastomoses and in 11 patients for secondary anastomoses following Hartmann procedures. Twenty-one anastomoses were at or near the dentate line. Fifty-six patients had rectal carcinoma, 29 patients had diverticulitis, 3 patients had carcinoma of the ovary, and 1 patient each had traumatic rectal perforation, volvulus, or rectal prolapse. Complications in the total 91 patients included 3 anastomotic leaks (3.3%), 1 postoperative hemoperitoneum (1.1%), and 3 strictures (3.3%). No anastomosis was protected by diverting colostomy. There were no operative deaths. Of 43 patients with cancer available for follow-up, 4 patients have developed local recurrence. The technique has been modified for ileoanal anastomosis during abdominal restorative proctocolectomy for ulcerative colitis and familial polyposis and early results are favorable. The double stapling technique provides a safe method for rectal reconstruction at or near the dentate line and offers the following advantages over other stapler techniques: (1) It eliminates the frustrating distal pursestring; (2) The rectal segment is not opened, minimizing contamination; and (3) It avoids gathering the sometimes generous circumference of the rectum on a pursestring thus allowing a more precise distal donut.

Anal Canal↗
PubMedDate not supplied

A double-blind, placebo-controlled study of the effect of imipramine on TRH-induced urinary urgency in healthy men.

We studied the effect of imipramine (IMI) on thyroid releasing hormone (TRH)-induced urinary urgency as a way of investigating the mechanism of the beneficial effect of IMI on enuresis. In a double-blind study, 12 normal, healthy men between 21 and 39 yr of age ranked their urge to urinate at 30-sec intervals following IV injection of TRH (500 micrograms) or saline. The subjects then were randomly assigned to either IMI (1 mg/kg) or placebo groups for 10 days, and the procedure was repeated. Compared to saline, TRH produced a significant elevation in urinary urgency in all subjects. IMI did not significantly blunt TRH-induced urinary urgency. Thus, the mechanism by which IMI affects enuresis is likely not mediated at the level of the urinary urgency induced by TRH.

Adult↗