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Biomedical subjects

C Gordon

Publications and source records attributed to C Gordon.

At least 217 records · Page 12Linked to original sources
PubMed1981

Method of addition of cellulose to experimental diets and its effect on rat growth and protein utilization.

The growth response of rats to experimental diets limiting in protein was used to evaluate two modes of addition of fiber. The first mode (trial A) used the more conventional approach of substituting cellulose for starch. The second mode (trial B) proceeded by total diet dilution, by which cellulose was added to a cellulose-free stock diet. Rats fed both types of diets compensated for the energy dilution and their digestible energy intake did not change markedly. However, both protein intake and growth increased with rising dietary cellulose levels in trial A and the protein efficiency ratio (PER) decreased. These did not change in trial B, except at the highest cellulose level, where growth and PER tended to decrease. Not only did the total diet digestibility and gross energy digestibility diminish upon the addition of cellulose to the diet, but the apparent protein digestibility also decreased in response to increasing dietary cellulose. We concluded that, in the design of experiments using high-fiber diets, careful consideration should be given to the effect which the method of dietary fiber addition has on the effective concentration of nutrients in the non-fiber portion of the diet and to the effect which variations in the parameter might have on nutrient utilization or biological responses to them. Our results indicate that, under conditions where protein is in limiting amounts in the low-fiber diets, total diet dilution is the more appropriate mode of dietary fiber addition. This conclusion may apply to other nutrients as well, but that remains to be proved.

Animals↗
PubMed1981

Phase I and pharmacological studies of pentamethylmelamine administered by 24-hour intravenous infusion.

A Phase I study of pentamethylmelamine (PMM) was conducted, administering the drug as a 24-hr i.v. infusion once weekly for 3 weeks. Doses ranged from 80 to 3000 mg/sq m/week. Twenty-six evaluable patients received a total of 30 courses of PMM. The median performance status of the patients was 60% (range, 40 to 90%), and the median age was 58 years (range, 43 to 72 years). The highest tolerated dose was 2000 mb/sq m/week. Nausea and vomiting were the dose-limiting toxicities; myelosuppression was neither consistent nor severe. One objective response lasting 10 months was noted in a patient with renal cancer. Pharmacokinetic studies using [ring-14C]PMM demonstrated a postinfusion half-life of 14C of approximately 12 hr, with the majority of the radiolabel excreted in the urine. PMM was introduced as a parenteral form of hexamethylmelamine. The present schedule does not permit administration of PMM in a dose greater than the tolerated dose of hexamethylmelamine and does not appear to offer an advantage over the p.o. use of the parent compound.

Adult↗
PubMed1980

Sleep apneic episodes as indications for adenotonsillectomy.

Fourteen children with adenoid and tonsillar hyperplasia were studied for one night in the sleep laboratory. Six of the children had at least 40 apneic episodes per night, mostly central or obstructive. The largest number of episodes was found in rapid eye movement sleep. Mixed episodes were the longest and central episodes the shortest. Adenotonsillectomy was performed on children with at least 40 episodes and on children with predominantly obstructive episodes. In two of these children, preoperative and postoperative recordings were taken, revealing a reduction in the total number of apneic episodes and a complete disappearance of obstructive episodes. These results suggest that polysomnographic recordings can provide useful information regarding the necessity of adenotonsillectomy.

Adenoidectomy↗
PubMed1980

Phase I evaluation of succinylated Acinetobacter glutaminase-asparaginase in adults.

Succinylated Acinetobacter glutaminase-asparaginase (SAGA) has broader antitumor activity than Escherichia coli L-asparaginase in experimental systems; moreover, drug resistance does not develop in tumor cell lines initially sensitive to this enzyme. We have investigated the pharmacology and toxicology of SAGA after both single-dose and serial daily dose injections in 20 adult patients. Glutaminase activity in plasma after i.v. injection of single doses did not follow simple first-order kinetics (half-life during the initial 24 hr was 21 +/- 9 hr. A linear relation was observed between increasing doses of SAGA and resultant levels of plasma enzyme activity and blood glutamate. Assay of whole blood which had been deproteinized immediately following phlebotomy showed that single doses of SAGA lowered glutamine only transiently to nondetectable levels; serial daily doses were required to achieve and maintain continuous glutamine depletion. Reversible depression of the central nervous system, ranging from encephalopathy to coma, occurred in a dose-related manner and was dose limiting. Other prominent reactions included respiratory alkalosis, hyperglycemia, nausea, and vomiting. Transient antitumor effects were noted in two patients with solid tumors and in two patients with leukemia. SAGA causes considerable neurotoxicity in adults which requires close patient monitoring. Phase II studies in leukemic patients are in progress.

Acinetobacter↗
PubMed1977

Extraction and analytic procedures for cytosine arabinoside and 1-beta-D-arabinofuranosyluracil and their 5'-mono-, di-, and tri-phosphates.

A qualitative and quantitative comparison of perchloric acid (PCA) and trichloroacetic acid (TCA) extraction procedures of biologic material containing cytosine arabinoside (Ara-C) and 1-beta-D-arabinofuranosyluracil (Ara-U) and their biologic 5'-phosphate derivatives revealed definite superiority of the PCA procedure over the TCA procedure. High-pressure liquid chromatography provides rapid and accurate quantitative and qualitative separation of both Ara-C and Ara-U and their 5'-mono-, di-, and tri-phosphates (mu Bondapak NH2 column), or their 5'-mono-, di-, and tri-phosphates without nucleosides (ABX Permaphase columns).

Animals↗
PubMed1976

Separation of 5'-mono-, di- and triphosphates of 1-beta-D-arabinofuranosylcytosine and of 1-beta-D-arabinofuranosyluracil by thin-layer and high pressure liquid chromatography.

The separation of all the 5'-mono-, di- and triphosphates of ara-C and ara-U by thin-layer (TLC) and high pressure liquid chromatography (HPLC) is described. Whereas for the TLC two different systems are necessary, HPLC allows a rapid separation of all the nucleotides with high resolution, reproducibility, and sensitivity within 15 minutes. An example of an HPLC separation of ara-C and ara-U nucleotides derived from a biological sample is presented.

Arabinofuranosyluracil↗
PubMed1972

Comparative clinical pharmacology of amoxicillin and ampicillin administered orally.

Ampicillin and amoxicillin (alpha-amino-p-hydroxybenzyl penicillin) were administered orally in 500-mg doses to eight fasting volunteers in a comparative study in which pharmacokinetic techniques were used. The absorption of amoxicillin was significantly better, as demonstrated by a higher mean peak serum concentration of 7.6 mug/ml as compared to 3.2 mug/ml for ampicillin, an average "area under the curve" that was approximately double that of ampicillin, and an 8-hr urinary recovery for amoxicillin of 60% as compared to 34% for ampicillin. Serum half-lives were the same for the two antibiotics, with values of 60.3 (+/-3.3) min for ampicillin and 61.3 (+/-5.6) min for amoxicillin. The latter drug gave measurable concentrations in the blood at 8 hr in all of eight volunteers, as compared to only three of eight with ampicillin.

Administration, Oral↗