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Biomedical subjects

D L Morris

Publications and source records attributed to D L Morris.

At least 379 records · Page 21Linked to original sources
PubMed1985

Coupling aminohexyl-FAD to proteins with dimethyladipimidate.

We used an efficient method having general applicability to couple N6-aminohexyl-flavin adenine dinucleotide (AHFAD) to several proteins for use in an apoenzyme reactivation immunoassay system (ARIS). AHFAD is first activated with 40-fold molar excess of dimethyladipimidate, excess imidate is removed rapidly by gel filtration, the activated product is incubated with the protein, and the conjugate formed is purified. This labeling technique permits incorporation of a controlled amount of amino-label into a protein, and eliminates the possibility of self-crosslinking, which would reduce the immunoreactivity of the conjugate. Here we demonstrate the utility of such a conjugate in a totally automated ARIS assay for thyroxin-binding globulin (TBG). After a competitive protein-binding reaction, apoglucose oxidase is added to combine with free TBG-AHFAD conjugate and produce active glucose oxidase, which is measured colorimetrically in a peroxidase-linked reaction. The assay covers the clinically significant range for TBG from 0 to 60 mg/L and has a throughput of 60 reactions in 75 min. Comparison with an RIA method (x) by regression analysis yielded the equation y = 0.890x + 1.217 (r = 0.975, n = 47, Syx = 1.906 mg/L).

Apoenzymes↗
PubMed1984

Optimal timing of operation for bleeding peptic ulcer: prospective randomised trial.

From October 1980 to September 1983 all patients with upper gastrointestinal bleeding were admitted to a centralised unit and investigated by early endoscopy. A total of 142 patients with a proved duodenal or gastric ulcer were randomised after stratification for age and site of ulcer to early (aggressive) surgical management or a delayed (conservative) policy. Significantly more operations (n = 42; 60%) were performed in the early than in the delayed (n = 9; 20%) groups (p less than 0.01). There were no deaths among the 42 patients under 60. The overall mortality in the 100 patients aged over 60 was 10% and when analysed on an "intention to treat" basis there was no difference between early and delayed surgery. When, however, an unrelated death from a bleeding colonic polyp was excluded and the data analysed on "treatment received" the mortality was only 2% in the early group compared with 13% in the delayed group (p less than 0.05). When analysis was confined to gastric ulcer the difference between early (0%) and delayed (24%) treatment was even greater. The results of this trial indicate that for patients over 60 an aggressive surgical policy is associated with a significant reduction in mortality.

Adult↗
PubMed1984

Implications of multiple mechanisms of carcinogenesis for short-term testing.

The attempt has been made recently to categorize carcinogens into two mechanistic types based on their mechanism of action: genotoxic (capable of reacting with and damaging DNA) and epigenetic (unable to damage DNA to any detectable extent). By requiring that a given chemical fit into one or the other of these narrowly defined categories for regulatory purposes, we are probably oversimplifying potential biological effects. In fact, based on our limited understanding of carcinogenic mechanisms, this artificial distinction should probably be abandoned in favor of a more precise statement of each chemical's mechanism or relative potency of initiating and promoting effects. Since the standard short-term tests by which carcinogenicity of chemicals is screened were designed to detect certain chemical classes with active electrophilic intermediates, weak or specialized carcinogens may be missed and may be assumed erroneously to be nongenotoxic. The mechanisms of carcinogenicity for such carcinogens may include particulate deposition, active radical formation, liver toxicity, and hormonal interactions. Not all of these secondary mechanisms depend upon a detectable level of binding to DNA, damage to DNA, or modification of the DNA sequence, even though they may demonstrate other characteristics of a complete carcinogen (that is, irreversibility and lack of a threshold). Certain agents have been labeled as epigenetic. However, a consideration of the literature on sample agents (diethylstilbestrol, asbestos, and urethane) reveals that these are not epigenetic carcinogens despite their being labeled as such. Agents with irreversibility and no threshold have initiating potential and, as such, are genotoxic, whereas carcinogens that are classified as nongenotoxic are largely agents that promote the growth of liver tumors. Even promotion can be a mechanistically specialized phenomenon. For example, some promoters are cytotoxic to the liver, but not all liver toxins are liver tumor promoters or liver carcinogens. Further, the carcinogens commonly labeled as epigenetic might cause a unique specialized genotoxicity not detected by common screening tests routinely used for detecting genotoxicity. If we assume that this unrecognized but necessary initiating potential is mediated by some specialized genotoxicity, extra care must be taken to establish a genuine lack of genotoxicity before an agent can be classified (and regulated) as a promoter (lacking the ability to initiate tumor growth but still enhancing tumor development).(ABSTRACT TRUNCATED AT 400 WORDS)

Asbestos↗
PubMed1984

Fracture and herniation of bowel at bone graft donor site in the iliac crest.

Fracture at a bone graft donor site in the iliac crest is an uncommon but documented occurrence. Herniation at this site requires a deep dehiscence of the wound, and is rare. A patient is reported with complete wound dehiscence in association with a fracture at a bone graft donor site in the iliac crest.

Adult↗
PubMed1984

A high incidence of bleeding is observed in a trial to determine whether addition of metronidazole is needed with latamoxef for prophylaxis in colorectal surgery.

A prospective randomized trial has compared the use of latamoxef sodium (two doses) with latamoxef and metronidazole for elective colorectal surgery. The incidence of wound infection in patients receiving latamoxef alone was 34 per cent compared with 32 per cent in patients receiving latamoxef and metronidazole. Only eight of the 36 wound infections in this study could be classified as major. Only two patients developed an intra-abdominal abscess postoperatively and there was only one episode of septicaemia. Postoperative haemorrhage was recorded in 17 patients (15 per cent). Twelve episodes of bleeding occurred in the first 97 patients who entered the trial and prolongation of the prothrombin time was recorded in eight of 16 patients. In view of these findings 10 mg vitamin K was given with each dose of latamoxef to the last group of patients. However, bleeding occurred in five of 13 patients receiving vitamin K and entry to the study was therefore discontinued.

Adult↗
PubMed1984

Prospective randomized trial of single dose cefuroxime against mezlocillin in elective gastric surgery.

A prospective randomized control trial was made in 78 patients undergoing elective operations on the stomach where the viscus was opened at operation, and the efficacy of single dose intravenous prophylaxis with cefuroxime 1.5 g or mezlocillin 2 g was compared. The overall rate of sepsis was 10.2 per cent. Infection in the cefuroxime group was significantly lower (2.5 per cent) than in the mezlocillin group (18 per cent) (P less than 0.05). Four of the seven patients with infections in the mezlocillin group were due to antibiotic resistant staphylococci. The only infections in the cefuroxime group were due to an antibiotic resistant strain of Pseudomonas aeruginosa. One case of pseudomembranous colitis occurred in the cefuroxime group. In view of the high rate of resistant organisms in patients receiving mezlocillin we believe that cefuroxime remains the antibiotic of choice for patients undergoing elective gastric operations.

Abscess↗
PubMed1984

Electrographic recording from bovine vomeronasal capsule under spontaneous and stimulated conditions.

The vomeronasal organ ( VNO ) is an accessory olfactory system which in many vertebrates seems to be involved in reproductive behavior, particularly in permitting males to detect estrus in conspecific females. We postulated that EEG-like field potentials could be recorded from the VNO because the organ has a sensory epithelium that can discharge in response to odorants, and because VNO receptor cells are structurally similar to cells in the olfactory mucosa that produce field potentials (the "electro- olfactogram "). We examined this postulate in male cattle by surgically implanting recording/perfusion cannulae into the ducts leading to each VNO . Both bipolar (between VNOs ) and reference recording revealed continuous spontaneous voltage fluctuations that were similar to an EEG, except that amplitudes were larger and frequencies slower. Simultaneous recording of the EEG and VNO , using the same nasal reference electrode revealed that neither signal was "contaminated" by voltages from the other. Perfusions of one VNO with whole urine, urine condensate, or aqueous reconstituted urine extracts, whether from females in estrus or in anestrus, produced massive transient electrical responses from both VNOs . Perfusion with penicillin or local anesthetics caused more sustained large electrical responses from both VNOs , except that activity became quiescent about 15 min after local anesthesia. These results suggest that it is feasible to use direct recording of VNO responses to stimulation to investigate the behavioral physiology of the VNO .(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Two-dimensional echocardiographic evaluation of the size, function and shape of the left ventricle in chronic aortic regurgitation: comparison with radionuclide angiography.

To evaluate the usefulness of two-dimensional echocardiography in asymptomatic or minimally symptomatic patients with significant aortic regurgitation and left ventricular enlargement, left ventricular size and function measurements obtained by a nongeometric technique, gated blood pool radionuclide angiography, were compared with measurements made by several two-dimensional echocardiographic methods in 20 patients. Left ventricular size was best assessed by an apical biplane modified Simpson's rule algorithm obtained by computer-assisted planimetry. For end-diastolic volume, r = 0.95 and standard error of the estimate = 25 ml; for end-systolic volume, r = 0.94 and standard error of the estimate = 16 ml. A newly introduced simplified two-dimensional method obviating the need for planimetry and using multiple axis measurements yielded satisfactory results, although volumes larger than 300 ml were markedly underestimated. Evaluation of volumes from a single minor axis measured directly from two-dimensional images and M-mode tracings obtained under two-dimensional echocardiographic control was inadequate for clinical use. Ejection fraction was correctly assessed by the modified Simpson's rule method as well as by the simplified two-dimensional method (r = 0.81 to 0.83, standard error of the estimate = 7%). However, when methods without planimetry were further simplified, a satisfactory correlation was no longer obtained. The M-mode approach using a corrected cube formula also provided an accurate estimation of ejection fraction, a finding that is attributed to the absence of regional wall motion abnormalities in this group of patients, the ability to locate the M-mode beam more adequately under two-dimensional control and the persistence of an ellipsoidal configuration and a circular cross section in the left ventricular chamber. The data indicate that two-dimensional echocardiography is a valuable approach to the assessment of left ventricular size and function in these patients. Moreover, this approach provides a practical and convenient way of improving M-mode evaluation of function and of determining left ventricular shape, thus permitting adequate selection of geometric algorithms for volume calculations.

Adult↗
PubMed1984

Mutagenicity in gastric juice.

Mutagenicity has been measured in the gastric juice of 228 patients using the Ames bacteriological test system; while mutagenicity in control and duodenal ulcer patients did not differ from saline controls, mutagenicity was significantly increased compared with controls in patients suffering gastric ulcer (p less than 0.002), carcinoma (p less than 0.002), and in patients after gastric resection (p less than 0.01). A transient rise in mutagenicity was seen following H2 antagonist ingestion (p less than 0.002). Increased levels of mutagenicity were found to correlate closely with gastric juice pH and bacterial count. Histidine concentrations in gastric juice did not explain the mutagenicity results.

Duodenal Ulcer↗
PubMed1984

Blood pressure during growth and development.

Data obtained from the United States Health and Nutrition Examination Survey of 1971-74 (HANES I) were analyzed to explore the relationship between blood pressure and differences in selected body measurements like weight, height, triceps skinfold, upper arm girth and heart rate. The period of growth and development was studied in a sample of 4238 persons aged 7-19 years. Strong concordance of the patterns of change in blood pressure up to age 14 years and of the patterns of correlations between blood pressure and various body measurements were seen in the four different groups analyzed (White males and females, Black males and females). From 14 years onwards differences in changes in several parameters were seen in both sexes and possibly also in the different racial groups.

Adolescent↗
PubMed1983

Serum cholesterol and cancer in the Hypertension Detection and Follow-up Program.

The relation between serum cholesterol and cancer incidence was investigated in the population of the Hypertension Detection and Follow-up Program. During the 5 years of follow-up, 286 new cancer cases were documented among the 10,940 participants. Overall, age-adjusted cancer incidence rates, computed by baseline serum cholesterol quartiles, showed a small, but statistically significant, inverse relation between serum cholesterol and cancer incidence. No evidence suggested that the observed relationship was primarily due to confounding by other cancer risk factors, association of low serum cholesterol with incipient but undiagnosed cancer, or problems of competing risks. However, the relationship is weak and a causal interpretation of these immediate results cannot be argued persuasively. Examinations of specific cancer sites and factors related to serum cholesterol are suggested as important lines of research toward clarification of the complex relationships observed.

Adult↗
PubMed1983

Clinical and microbiological evaluation of piperacillin in elective biliary surgery.

Fifty patients undergoing electric biliary surgery were given piperacillin 2 g i.m. 2 h preoperatively followed by 2 g i.v. at the beginning of the operation. Venous blood and bile from the gall bladder and common bile duct were assayed for piperacillin. Blood levels exceeded 100 mg 1(-1) in all instances unless the protocol was not followed. Both gallbladder and common bile duct bile levels exceeded 50 mg 1(-1), and the only exceptions were due to poor penetration into three obstructed gallbladders. Common bile duct levels exceeded 50 mg 1(-1) even in the presence of obstructive jaundice. Only one patient developed a minor postoperative wound infection.

Bacteria↗