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Biomedical subjects

C Campbell

Publications and source records attributed to C Campbell.

At least 199 records · Page 11Linked to original sources
PubMed1994

Effects of forage particle size and long hay for cows fed total mixed rations based on alfalfa and corn.

A 2 x 2 factorial arrangement of treatments, in which particle length of alfalfa silage in the TMR and supplementary long alfalfa-grass hay were the factors, was used to determine whether hay benefits lactating cows and whether its effects depend on fibrosity of the main forage source. Without supplementary hay, TMR contained 45% forage, including corn silage, and 26 to 27.5% NDF. When hay was fed, the amount of alfalfa silage in the corresponding TMR was reduced. In the production trial, 40 cows (20 multiparous) were fed the diets for 8 wk in early lactation. No interactions of silage length and hay occurred on any production variables except lactose concentration in the milk of multiparous cows. Addition of hay to the diet enhanced DMI, without effect on production, so efficiency of milk production was reduced. Shorter alfalfa silage enhanced DMI by multiparous cows, reduced SCM and FCM in primiparous cows, and depressed fat test in both groups. Milk composition and component production generally were unaffected. Five rumen-fistulated cows in early to midlactation each were given the four treatments during four 3-wk periods. Hay enhanced rumination when short alfalfa silage was fed but tended to reduce it on long alfalfa silage. Hay also depressed rumen pH and enhanced VFA concentrations. Alfalfa silage length had minimal effects on rumination and no effect on fermentation, and neither hay nor silage length affected digestion of silage DM or NDF in the rumen. Addition of hay to the diet may not be beneficial for cows fed TMR, but longer term feeding studies are needed.

Ammonia↗
PubMed1994

Hospital plant and equipment replacement decisions: a survey of hospital financial managers.

Surveys of capital investment decisions have often neglected issues related to replacement of existing plant and equipment. As acute care hospitals experience declining inpatient utilization, appropriate hospital capital replacement becomes critical to efficiency and survival. Financial managers of 116 large, acute care hospitals were asked to rank factors that typically affect decisions to replace plant and equipment in their facilities. Factors influencing plant were expected to differ from those affecting equipment. The study found that replacements, particularly of equipment, are largely dictated by physicians, accreditors, and regulators. Rising operating costs and utilization were ranked as less important in replacement decisions. In light of impending health reform, these findings suggest that hospital executives need to reorder their replacement priorities to emphasize cost and efficiency.

Capital Expenditures↗
PubMed1994

Career management: pay considerations.

As nurse managers move into new and expanded leadership roles, there are many considerations. One issue that frequently arises is pay--how to negotiate your own pay and how to be sure you receive a reasonable compensation package. This article addresses the most common issues and gives examples of practical approaches.

Career Mobility↗
PubMed1994

The role of computerized tomography in shoulder arthrography.

Double contrast computerized tomographic (CT) shoulder arthrograms of 55 shoulders were reviewed. This investigation was compared with conventional arthrograms and the findings were correlated with subsequent clinical and surgical follow-up. CT arthrograms were found to be useful in demonstrating bony, ligamentous and cartilaginous structures and have helped the surgeon in deciding the approach and type of surgical procedure. Indications for CT arthrography are recurrent dislocation, multidirectional instability, severe rheumatoid arthritis and other arthritides, complex shoulder deformities and suspected loose bodies. We found that this examination was not as helpful for rotator cuff injuries, impingement syndrome, adhesive capsulitis and in cases of vague or mild shoulder pain.

Adolescent↗
PubMed1994

Lung and systemic oxidant and antioxidant activity after graded smoke exposure in the rat.

We wanted to determine the effect of a graded smoke inhalation on lung and systemic oxidant stress, and its relationship to physiological and histological change. Male Wistar rats were given 12 breaths of 10 ml/kg (n = 8) (group 1) or 20 ml/kg (n = 8) (group 2) tidal volume, using cotton toweling smoke through the trachea using positive pressure. Rats were monitored, then killed at 24 hr. Data were compared to controls (n = 8). Peak group 1 and group 2 carboxyhemoglobins were 22 +/- 6 and 46 +/- 6%, with a mortality prior to 24 hr of 14% and 50%, respectively. Group 1 rats showed only moderate lung dysfunction but with severe airway inflammation and edema, alveolar inflammation and atelectasis, with a decrease in PaO2 from the control of 96 +/- 4 to 72 +/- 5 torr. No increase in lung, liver, or kidney oxidant-induced lipid peroxidation, measured as malondialdehyde lung, liver, or kidney oxidant-induced lipid peroxidation, measured as malondialdehyde (MDA), or decrease in the antioxidant defenses catalase was noted. Group 2 rats demonstrated severe airways edema, alveolar atelectasis, and alveolar edema, and a PaO2 decreasing below 60 torr, corresponding with a 3-fold increase in lung tissue MDA and 35% decrease in catalase. In addition, liver and kidney tissue MDA doubled, and catalase activity decreased by 40%. Increased oxygen consumption was also demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1994

Effects of antiplatelet therapy with indobufen or aspirin-dipyridamole on graft patency one year after coronary artery bypass grafting.

Saphenous vein coronary artery bypass graft patency can be increased by antiplatelet therapy. Aspirin plus dipyridamole are effective but are associated with tolerability problems. Indobufen is a possible alternative antiplatelet agent that may be better tolerated. A prospective, randomized, double-blind, parallel-group study was undertaken to compare the efficacy and safety of indobufen 200 mg twice daily with aspirin 300 mg thrice daily plus dipyridamole 75 mg thrice daily in preventing occlusion of autologous saphenous vein coronary artery bypass grafts. A total of 803 patients were randomized in the study, of whom 552 had a follow-up coronary angiogram approximately 1 year after operation. All anastomoses were patent in 56% of indobufen-treated patients and 59% of aspirin-dipyridamole recipients (p = 0.384). The percentage of all anastomoses patent was 82% in the indobufen group and 83% in the aspirin-dipyridamole group (p = 0.297). Mean postoperative blood loss was significantly less in the indobufen group (p = 0.043). Patients who received indobufen also had significantly fewer adverse events considered to be treatment-related compared with aspirin-dipyridamole recipients (p = 0.02). At the doses tested indobufen was as effective as aspirin plus dipyridamole in preventing occlusion of saphenous vein grafts and was better tolerated. Because indobufen was associated with less postoperative blood loss it may be used before operation in coronary artery bypass grafting.

Adolescent↗
PubMed1993

Wavelength specific patterns of p53 induction in human skin following exposure to UV radiation.

We report that, in human skin, exposure to equally erythemogenic doses of UVA, UVB, and UVC increases immunocytochemically detected p53 in a wavelength-specific pattern. UVC produced immunostaining confined to the upper epidermis. With UVB, staining was seen throughout the epidermis, whereas with UVA staining predominated in the basal layer. The results with UVB and UVC are understandable on the basis of their known differences in penetration, whereas those with UVA are not. This suggests that within one cell type the pattern of p53 response to UV radiation is wavelength dependent.

Adult↗
PubMed1993

Increased hepatocyte expression of hepatitis B virus transcription in patients with features of fibrosing cholestatic hepatitis.

BACKGROUND: Recurrent hepatitis B after liver transplantation may be complicated by fibrosing cholestatic hepatitis. This syndrome is associated with rapid graft failure and is characterized by ballooning degeneration of hepatocytes and abundant viral antigen expression. METHODS: To study this disorder further, in situ hybridization studies were performed on 36 liver biopsy specimens from 14 transplanted patients with recurrent hepatitis B and 18 nontransplanted controls with chronic hepatitis B. Biopsy specimens were scored for histological features and intensity of riboprobe hybridization signal to hepatitis B virus (HBV) DNA and RNA. RESULTS: HBV DNA hybridization signals of 2+ to 3+ intensity were observed in 53% of the posttransplant biopsies but none of the nontransplanted samples (P < 0.001). HBV RNA signals of this intensity were found in 42% of the transplant biopsy specimens compared with 17% of the nontransplant specimens (P < 0.07). Features of fibrosing cholestatic hepatitis were noted in 12 biopsies; 11 of these displayed RNA signals of 2+ to 3+ intensity (92%) compared with 4 of 24 (17%) biopsy specimens without this diagnosis (P < 0.001). The level of hepatocyte RNA correlated with the extent of hepatocellular ballooning (P < 0.007). CONCLUSIONS: These data suggest that fibrosing cholestatic hepatitis is associated with enhanced hepatitis B virus transcription and support a cytopathic role for the virus in the development of this syndrome.

Adult↗
PubMed1993

Relationship between liver oxidant stress and antioxidant activity after zymosan peritonitis in the rat.

OBJECTIVE: To determine the effect of a severe nonbacterial-dependent peritonitis on the degree and time course of liver oxidant stress and antioxidant activity. DESIGN: Prospective, randomized, controlled study. SETTING: Animal laboratory. SUBJECTS: Thirty-eight male Sprague-Dawley rats were injected with zymosan 0.75 mg/g body weight, mixed in mineral oil, and fluid resuscitated. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Oxygen consumption (VO2), base deficit, and blood gases were determined. Liver tissue oxidized and reduced glutathione, malondialdehyde catalase, xanthine oxidase, and xanthine dehydrogenase were measured and data were compared with both a pair-fed and an ad libitum fed group over a 24-hr period. We noted a 30% mortality rate with animals dying between 20 and 24 hrs. Peak decrease in VO2 occurred at 12 hrs, corresponding with a metabolic acidosis. Marked liver oxidant stress was seen at 4 hrs with oxidized glutathione increased from a control value of 0.2 +/- 0.1 to 1.1 +/- 0.2 mg/g of tissue, while reduced glutathione decreased from a control value of 1.8 +/- 0.1 to 0.3 +/- 0.1 mg/g. By 24 hrs, oxidized glutathione activity was no longer increased, but reduced glutathione concentrations were still markedly decreased. Tissue catalase was also significantly decreased at the 24-hr period. Liver malondialdehyde was increased at 24 hrs when the peak decrease in antioxidants was evident. Liver xanthine oxidase activity increased significantly from 15 +/- 3 to 45 +/- 8 mumol uric acid/min/g by 4 hrs and remained increased, with the initial increase predating evidence of impaired perfusion. Pair-fed animals demonstrated no changes in oxidant or antioxidant activity. CONCLUSIONS: We conclude that a marked increase in liver oxidant stress and decrease in antioxidant activity occurs in the first several hours after the onset of nonbacterial peritonitis. An early increase in liver xanthine oxidase activity may be a source of the oxidants. Decreased liver antioxidant activity persists well after the oxidant stress resolves.

Acidosis, Lactic↗
PubMed1993

Relationship of burn-induced lung lipid peroxidation on the degree of injury after smoke inhalation and a body burn.

OBJECTIVE: We compared the effect of a modest smoke inhalation injury, a burn injury alone, and a smoke inhalation injury plus a body burn, on the degree of lung oxidant-induced lipid peroxidation and lung injury. DESIGN: Prospective animal study with concurrent controls. SETTING: An animal laboratory. SUBJECTS: Forty-four adult yearling female sheep (weight range 45 to 50 kg). INTERVENTIONS: Forty-four sheep were prepared with lung and prefemoral (soft tissue) lymph fistulas. Twelve breaths of cooled smoke with tidal volume of 10 mL/kg body weight were given to 24 sheep, producing a peak blood carboxyhemoglobin of 25% to 30%. Twelve sheep also received a 15% total body surface third-degree burn. Sheep were killed at 4 or 24 hrs. MEASUREMENTS AND MAIN RESULTS: Circulating lipid peroxidation was monitored as conjugated dienes and tracheobronchial mucosal and lung parenchyma as malondialdehyde. Antioxidant defenses were monitored by catalase activity. Lung physiologic and histologic changes were compared. We noted intense airways inflammation in both smoke inhalation groups and lung parenchymal inflammation in all groups. Lung lymph flow was modestly increased (two-fold) in the smoke inhalation groups. Alveolar water content was not significantly increased after any injury. PaO2 was decreased at 24 hrs after the smoke insult alone. Parenchymal malondialdehyde content did not increase with the smoke insult alone, but did increase from a control value of 110 +/- 20 to 270 +/- 24 nmol/g tissue by 4 hrs in the combined burn and smoke injury group, while catalase activity decreased. Airway mucosal malondialdehyde did not increase in any group. CONCLUSIONS: We conclude that alveolar capillary permeability is not increased early after a moderate smoke injury or smoke injury with burn. Lipid peroxidation is not increased in large airway or lung parenchyma with early after-smoke exposure. The addition of a burn significantly increases lung parenchymal lipid peroxidation, but the oxidant changes do not correspond with the degree of early lung dysfunction.

Animals↗
PubMed1993

p53 mutations are common and early events that precede tumor invasion in squamous cell neoplasia of the skin.

Mutations of the p53 gene are the most common genetic abnormality described in human cancer; p53 mutations have recently been reported in more than half of the cases of squamous cell carcinomas of the skin. We have previously reported positive p53 immunostaining in Bowen's disease and actinic keratosis. To determine if this abnormal immunostaining reflects p53 mutation or alternative pathways of p53 protein inactivation we have performed direct sequencing of p53 in 20 further cases of Bowen's disease. We found eight mutations in 20 cases, seven of which would produce alterations in the p53 protein product. Our results suggest that p53 mutation is an early event in malignant conversion, frequently preceding invasion in squamous cell neoplasia of the skin. The type and site of the observed mutations reflect known mutational hotspots and support the role of ultraviolet radiation in the pathogenesis of these tumors.

Base Sequence↗
PubMed1993

The relation between p53 mutation and p53 immunostaining in non-melanoma skin cancer.

Extensive study of the p53 gene has established its role as a tumour-suppressor gene, and the involvement of mutant p53 in a wide spectrum of human malignancy. Many mutations of p53 result in a protein product that is abnormally stable, so that it becomes readily detectable by immunocytochemistry. In contrast, under normal conditions, it has been considered that levels of wild-type p53 were too low to be detectable. Although positive immunocytochemistry has been used as a marker of mutation, recent evidence suggests that this assumption may not always be valid. We have carried out both PCR-sequencing of exons 5-8 of the p53 gene in 20 basal cell carcinomas (BCC), and immunocytochemistry of these tumours with the anti-p53 antibody DO7. Twenty cases of Bowen's disease, in which we had previously documented mutations, were also immunostained. We report a low rate of p53 mutation in the BCCs we examined (2/20), and a discrepancy between tumours with positive immunostaining and those with mutation in both Bowen's disease and BCC. Of eight tumours in which we detected mutation, only four were immunopositive: of 19 immunopositive samples, only four showed detectable mutation. We discuss the implications of our results for the use of positive immunostaining in clinical diagnosis, and the involvement of p53 in skin carcinogenesis.

Aged↗
PubMed1993

Codon 12 Harvey-ras mutations are rare events in non-melanoma human skin cancer.

ras mutations have been reported as an early event in some human malignancies and in the mouse skin model of multistep carcinogenesis; early studies in human non-melanoma skin cancers have reported variable rates of ras mutations. A recent study, however, has reported a high frequency of activating mutations of the Harvey-ras proto-oncogene in non-melanoma skin cancers, and the site specificity of the mutation at the second position of codon 12 prompted us to re-examine the importance of Ha-ras codon 12 mutations as an early event in the development of these tumours, using a combination of PCR and restriction fragment polymorphism of codon 12 of the Ha-ras gene. Dilution experiments confirmed that the method was sensitive and capable of detecting mutations at this codon when only 4% of the total alleles are mutated. We were surprised to find no mutations in the 40 basal cell carcinomas, 12 squamous cell carcinomas and 12 cases of Bowen's disease studied. We conclude that Ha-ras codon 12 mutations are rare events in human non-melanoma skin cancer in the U.K. The marked differences in the frequency of codon 12 Ha-ras mutations in published studies may relate to either technical artefacts, or differences in the molecular epidemiology between areas of low and high sun exposure.

Base Sequence↗
PubMed1993

Monitoring of antiviral therapy with quantitative evaluation of HBeAg: a comparison with HBV DNA testing.

The serological endpoint of response in the treatment of chronic hepatitis B is the loss of hepatitis B virus DNA and HBeAg. Because the quantitative measurement of hepatitis B virus DNA in serum has been shown to be useful for monitoring and predicting response to interferon-alpha therapy, we decided to evaluate whether changes in HBeAg concentration could also be used in this manner. Twenty-nine patients who were initially positive for HBeAg and HBV DNA were serially evaluated for HBeAg concentration with a microparticle-capture enzyme immunoassay. HBeAg levels in serum were calculated by means of comparison with a standard curve of fluorescence rate vs. HBeAg concentration. The results, expressed in milliunits per milliliter, were compared with hepatitis B virus DNA levels determined by means of solution hybridization. The baseline HBeAg concentration proved to be the best independent predictor of response on stepwise Cox regression analysis (p = 0.026). Similar disappearance curves were observed for the two markers, although hepatitis B virus DNA became undetectable at an earlier interval in 13 of 16 cases (81%). In the 16 responders, a decline in HBeAg concentration of more than 90% was observed by wk 12 of therapy (mean +/- S.D., 95% +/- 13%). Nonresponders did not demonstrate such steep declines in HBeAg values by wk 12 (mean +/- S.D., 45% +/- 27%), and levels tended to increase at subsequent time points. We conclude that serial monitoring of HBeAg concentration with a technique that should be readily adaptable to clinical laboratories may be useful in the initial evaluation and monitoring of patients undergoing antiviral therapy.

DNA, Viral↗
PubMed1993

The effect of acute nonbacterial dependent peritonitis on lung and liver oxidant stress and antioxidant activity.

BACKGROUND: The role of oxidant release and tissue antioxidant defenses on inflammation-induced organ injury is not clearly defined. METHODS: We determined the effect of acute zymosan peritonitis in rats on lung and liver tissue oxidant stress and antioxidant defenses during a 5-day period. Oxidant activity was measured as tissue malondialdehyde and oxidized glutathione (GSSG). Antioxidant activity was measured as tissue-reduced glutathione (GSH) and catalase activity. Rats were maintained hydrated with subcutaneous crystalloid. Animals were killed at 4, 12, and 24 hours and 5 days. RESULTS: Acute peritonitis was evident at 12 and 24 hours but was resolving at 5 days. Peritoneal fluid cultures were negative after 24 hours. A 50% mortality rate was noted between 20 and 30 hours, with no deaths after 30 hours. We noted a significant increase in lung GSSG and malondialdehyde at 4 hours that persisted for the 5 days, as did histologic evidence of a progressing severe lung inflammation. No increased conversion of lung xanthine dehydrogenase to xanthine oxidase was noted. Lung GSH and catalase activity were maintained at control despite negligible food intake. In contrast, liver GSSG was increased significantly only at the 4-hour period, corresponding with a transient conversion of xanthine dehydrogenase to xanthine oxidase from 10% to 31%. Tissue malondialdehyde did not increase despite the initial oxidant stress. However, tissue GSH and catalase values decreased by more than 50% after 24 hours and remained decreased at 5 days. CONCLUSIONS: We conclude that early lung and liver oxidant stress is initiated by acute peritonitis. Lung oxidant changes persist and lung dysfunction progresses, even though antioxidant activity is maintained and acute peritonitis is resolving. Liver lipid peroxidation did not develop despite oxidant release, probably because of a large antioxidant reserve. However, a severe and sustained decrease in liver antioxidants results, increasing the potential damage from a subsequent oxidant insult.

Animals↗