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Biomedical subjects

J W Carter

Publications and source records attributed to J W Carter.

At least 19 recordsLinked to original sources
PubMed1994

Distribution of intestine-associated lymphoid tissue, aberrant crypt foci, and tumors in the large bowel of 1,2-dimethylhydrazine-treated mice.

Six-week-old male CF-1 mice were fed the AIN-76 diet, given eight weekly s.c. injections of either the colon carcinogen 1,2-dimethylhydrazine or saline, and killed 24 weeks after the last injection. Parameters measured in the large bowel included the incidence and locations of all intestine (gut)-associated lymphoid tissue (GALT) sites; the locations, incidence, and sizes of all aberrant crypt foci (ACF); and the incidence, locations, and types of all overt tumors. In saline-treated mice the distribution of GALT along the length of the large bowel was bimodal, with a majority peak of lymphoid nodules occurring in the distal large bowel and a minority peak occurring in the proximal large bowel. No ACF or tumors were present in the large bowel of the saline-treated mice. In 1,2-dimethylhydrazine-treated mice the majority of ACF were present in the middle third of the colon, between the two peaks of GALT, but the majority of the tumors were found over the GALT in the distal colon. There was a significant positive linear regression relationship between the numerical distribution of GALT and the numerical distribution of tumors along the length of the large bowel. There was no significant relationship between the distribution of ACF and the distribution of (a) tumors or (b) GALT along the length of the large bowel. Thus the numerical density of lymphoid nodules, not the numbers or distribution of ACF, was the significant predictor of the distribution of tumors in the large bowel of 1,2-dimethylhydrazine-treated mice. It is proposed that lymphoid nodules in the distal large bowel play a promotional role following initiation of colon carcinogenesis and that ACF have little if any malignant potential in the mouse.

1,2-Dimethylhydrazine↗
PubMed1989

The effect of exercise on bleeding time and local production of prostacyclin and thromboxane.

Exercise at a heart rate corresponding to 30% VO2max for 15 min was associated with an increase in the volume of bleeding time blood from a mean of 133 microliters before exercise to a mean of 218 microliters during and immediately after the exercise. There was similarly an increase in thromboxane B2 production from 6.40 nmol.l-1 before to 11.50 nmol.l-1. Most subjects also showed an increase in the length of the bleeding time and in the production of bleeding time 6-keto-PGF1 alpha. The extent of increase in the bleeding time and in production of 6-keto-PGF1 alpha was quite variable, with subjects showing the largest increases in bleeding time also demonstrating the greatest increases in 6-keto-PGF1 alpha (r = 0.76, P = 0.004). The ingestion of aspirin before exercise markedly inhibited basal bleeding time thromboxane B2 production and blocked the exercise-associated increments in thromboxane B2 and 6-keto-PGF1 alpha production. While the aspirin itself increased the length of the bleeding time, there was not any further increase associated with exercise. In contrast to the effects of acute short-term exercise, long-distance running was associated with a significant decrease in bleeding time, but no change in bleeding time blood volume, bleeding time thromboxane B2, or bleeding time 6-keto-PGF1 alpha. The results show that acute low-level exercise can be associated with significant changes in the volume of blood oozing from a bleeding time incision and in the amount of thromboxane production stimulated at the incisional site. Following exhaustive exercise of long duration, the above changes are no longer seen.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Diaphragmatic trauma in southern Saskatchewan--an 11-year review.

An 11-year retrospective review of 51 patients with diaphragmatic injuries revealed 33 blunt and 18 penetrating injuries. In the blunt trauma group 24 were left-sided and nine were on the right side. Preoperative diagnosis was made in 24 patients. Delayed diagnosis (greater than 24 hours) during life occurred in four patients and two injuries were found at autopsy. Chest X-ray was diagnostic or highly suggestive in 23 patients. All patients in this group had associated extra-abdominal injuries; 23 patients had concomitant intraabdominal injuries. Transabdominal repair was performed in 24 patients. Four deaths occurred in the blunt injury group. The penetrating diaphragmatic wounds consisted of 14 left-sided, three right-sided, and one pericardial wound. Preoperative diagnosis occurred in only three patients. The penetrating wound, hypotension, or peritoneal signs dictated operation in the remaining 15 patients. One death occurred from peritonitis and septic shock. Blunt and penetrating diaphragmatic injuries remain a diagnostic challenge and associated injuries determine the outcome.

Accidents, Traffic↗
PubMed1987

Choledochoduodenostomy. A safe and efficacious alternative in the treatment of biliary tract disease.

A review of 75 patients who underwent side-to-side choledochoduodenostomy as primary or secondary treatment for various forms of biliary tract disease was performed. Ages of patients ranged from 23 to 89 years (mean of 61 years), with 40 per cent of patients 70 years or older. All anastomoses were created with a minimal diameter of 2 cm. During a follow-up period ranging from 6 months to 8 years, there was no incidence of ascending cholangitis or anastomotic stricture. Six patients continued to have non-specific complaints of abdominal pain postoperatively that could not be attributed to the "sump syndrome" after necessary diagnostic studies were performed. The overall morbidity and mortality was 6.6 per cent and 1.3 per cent, respectively. This study confirms the notion that choledochoduodenostomy can be performed safely, with good results, particularly in the expanding high-risk elderly patient population.

Adult↗
PubMed1984

Identification and counting of asbestos fibers.

A combined analytical electron microscopic/optical count method for the determination of airborne asbestos fibers was tested for precision and bias. A modified phase contrast microscopic count method (NIOSH Method 7400) was used to determine total fiber content. The analytical electron microscope (AEM) procedure was added to identify the fraction of amosite asbestos fibers in airborne, laboratory-generated samples containing amosite and wollastonite fibers. Then this fraction was applied to the routine optical counts of all the samples in the set to estimate the asbestos fiber concentration. The effects of sample to sample, wedge to wedge, within wedge and between and counter variability were examined. In addition, the variabilities of the elemental ratio within a fiber and between fibers was also determined to find their possible influence on the ability to identify the fiber as amosite in the presence of other silicate fibers. A precision of 20.1% relative standard deviation (RSD) and a bias of -9.1% for the AEM count method compared with the optical count procedure were found for these mixed fiber samples.

Air Pollutants↗
PubMed1982

The responses of plasma biochemical parameters to a 56-km race in novice and experienced ultra-marathon runners.

A number of blood biochemical parameters, including the activities of the plasma enzymes creatine kinase (CK), aspartate aminotransferase (ASAT), lactate dehydrogenase and alkaline phosphatase, were measured in 23 athletes before, and immediately after a 56-km running race. Of the 23 athletes, 18 had previously completed standard 42-km marathon or longer (up to 90-km) ultra-marathon races, whereas not one of the other five athletes had previously run in a long-distance race. After the race, plasma CK and ASAT activities had both risen at least 280% more in the novice runners despite their much slower mean running speed (9.8 +/- 0.4 vs. 13.8 +/- 0.3 hm/h). There were no other inter-group differences in the absolute levels of the other measured biochemical parameters, although the rise in plasma calcium during the race was significantly greater in the experienced marathon runners. This study shows that either higher levels of training, or previous ultra-marathon racing experience, or both, is associated with lower immediate post-exercise levels of plasma enzyme activity. This is compatible with the finding that physical training reduces post-exercise plasma enzyme levels.

Adult↗
PubMed1980

Acutely administered polychlorinated biphenyls (PCBs) decrease splenic cellularity but increase its ability to cause graft-versus-host reactions in BALB/c mice.

A single intraperitoneal injection of 1000 mg/kg body weight of a PCB mixture (Aroclor 1242) to adult male BALB/cc mice caused not only a relative spleen enlargement, but also an absolute spleen lymphocyte depletion. However, there was an enrichment of spleen T cells necessary to cause a graft-versus-host reaction (GVHR) in (C3H x BALB/c) F1 neonates. The effect was present 6 days after PCB administration and was no longer present on days 12-13. These studies suggest a transient effect of acutely administered PCBs on splenic lymphocytes (B cells, null cells, some T cells) other than mature GVH inducing T cells. The effect may be either similar to or possibly indirectly mediated by corticosteroids.

Animals↗
PubMed1978

Infectious mononucleosis in the older patient.

Six cases of infectious mononucleosis in patients more than 60 years old were reviewed. The geriatric patient with infectious mononucleosis often presents with nonspecific constitutional symptoms, without exudative pharyngitis. The disease may present as fever of obscure origin or mimic chronic lymphocytic leukemia in this age group. Diagnosis is established through characteristic findings on hematologic and serologic studies.

Age Factors↗