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Biomedical subjects

C R Brown

Publications and source records attributed to C R Brown.

At least 109 records · Page 6Linked to original sources

Evaluation of intravenous ketorolac administered by bolus or infusion for treatment of postoperative pain. A double-blind, placebo-controlled, multicenter study.

BACKGROUND: Ketorolac is a nonsteroidal analgesic that may provide postoperative analgesia without opioid-related side effects. This double-blind, randomized, multicenter study evaluated the analgesic efficacy and safety of intravenous ketorolac in 207 patients during the first 24 h after major surgery. METHODS: Subjects were assigned to receive one of three analgesic regimens: a ketorolac infusion, ketorolac boluses, or placebo. All subjects had access to intravenous morphine via patient-controlled analgesia (PCA). Evaluations included PCA morphine used, pain assessment (categorical pain intensity scores and visual analogue pain scores), pain relief (categorical pain relief scores), sedation, presence of adverse events, and overall rating of regimens by study observers and patients. RESULTS: Patients in the ketorolac infusion group (but not the ketorolac bolus group) used less morphine (average 33 mg) than did the placebo group (44 mg) (P = 0.009). Significant differences favoring both ketorolac groups were seen in the pain intensity and the categorical pain relief scores at various time points during the study. At the termination of the study, compared with the placebo group, categorical pain intensity scores were lower in the ketorolac bolus group; visual analogue pain scores were lower in both ketorolac groups; and pain relief scores were higher in the ketorolac bolus group. The incidence of vomiting was significantly greater in the placebo group (27%) than in the ketorolac infusion group (12%) or bolus group (9%) (P = 0.032 and P = 0.005, respectively). The incidence of postoperative fever was 10% in the ketorolac bolus group and 25% in the placebo group (P = 0.013). Study observers noted less nursing difficulty while caring for patients in the ketorolac infusion group (P = 0.015). Study observers and patients in both ketorolac groups reported statistically significant overall drug superiority compared with placebo. CONCLUSIONS: It is concluded that intravenous boluses or infusions of ketorolac in conjunction with PCA morphine provide effective, safe analgesia after major surgery and improve on the response to PCA morphine alone.

Adult↗

Effects of dexamethasone on cytokine and phorbol ester stimulated c-Fos and c-Jun DNA binding and gene expression in human lung.

Glucocorticosteroids have a wide variety of effects which result in the long-term dampening of inflammatory responses. An important site of steroid action may be on the control of the activator protein-1 (AP-1) binding to deoxyribonucleic acid (DNA). AP-1 is a proinflammatory transcription factor composed of a heterodimer of Fos and Jun proto-oncogenes, which can be induced by phorbol esters and various cytokines. We have examined the hypothesis that dexamethasone may inhibit inflammation via an effect on AP-1 activation in human lung tissue. The effect of dexamethasone on the phorbol ester and cytokine activation of AP-1 and its monomers was examined in human lung tissue obtained from transplantation donors. AP-1 activation was measured by its ability to bind DNA, its localization in the nucleus by Western blotting, and the levels of fos and jun messenger ribonucleic acids (mRNAs) using Northern blotting. The phorbol ester, phorbol myristate acetate (PMA), caused a significant 2-3 fold increase in AP-1 DNA binding, which was sustained for 24 h and completely attenuated by co-incubation with dexamethasone. Dexamethasone alone caused a 40% decrease in AP-1 DNA binding. Dexamethasone modulated the expression of both c-jun and c-fos mRNA and produced long-term (24 h) 40% reduction in both mRNAs when compared to control tissues. PMA induced a rapid and prolonged increase in c-Fos and c-Jun nuclear localization, which was not attenuated by co-incubation with dexamethasone.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Northern↗

Pulmonary varices presenting as a solitary lung mass in a patient with end-stage liver disease.

A man undergoing evaluation for liver transplantation was found to have an asymptomatic chest mass, which further evaluation revealed to be pulmonary varices. The left hilar lesion was discovered on a screening chest x-ray film and confirmed by a computed tomographic scan of the thoracic cavity. Bronchoscopy was nondiagnostic, and a thoracotomy was required to diagnose the vascular lesion and exclude carcinoma. The pathophysiology of this pulmonary venous anomaly appeared to be related to portal hypertension, since esophagogastric and colonic varices also were present and the pulmonary varices resolved after liver transplantation. This is the first reported case of pulmonary varices caused by portal hypertension.

Diagnosis, Differential↗

Severe blunt assault injuries at Auckland Hospital.

The incidence and nature of severe blunt assault injury in the Auckland region was assessed by a retrospective review over a 2-year period. Approximately 14,000 charges of assault (excluding paediatric and sexual assault) were laid during this period. A total of 1035 people were admitted to hospital. Of 331 patients admitted to one hospital, 35 patients were admitted via the resuscitation room after severe assault; of these, two died. Of these patients, 33 were male and 19 of 21 ethanol levels measured were greater than 17 mmol/l. Head and facial injuries were the most frequent.

Adolescent↗

The constitutive and stress inducible forms of hsp 70 exhibit functional similarities and interact with one another in an ATP-dependent fashion.

Mammalian cells constitutively express a cytosolic and nuclear form of heat shock protein (hsp) 70, referred to here as hsp 73. In response to heat shock or other metabolic insults, increased expression of another cytosolic and nuclear form of hsp 70, hsp 72, is observed. The constitutively expressed hsp 73, and stress-inducible hsp 72, are highly related proteins. Still unclear, however, is exactly why most eukaryotic cells, in contrast to prokaryotic cells, express a novel form of hsp 70 (i.e., hsp 72) after experiencing stress. To address this question, we prepared antibodies specific to either hsp 72 or hsp 73 and have compared a number of biological properties of the two proteins, both in vivo and in vitro. Using metabolic pulse-chase labeling and immunoprecipitation analysis, both the hsp 72 and hsp 73 specific antibodies were found to coprecipitate a significant number of newly synthesized proteins. Such interactions appeared transient and sensitive to ATP. Consequently, we suspect that both hsp 72 and hsp 73 function as molecular chaperones, interacting transiently with nascent polypeptides. During the course of these studies, we routinely observed that antibodies specific to hsp 73 resulted in the coprecipitation of hsp 72. Similarly, antibodies specific to hsp 72 were capable of coprecipitating hsp 73. Using a number of different approaches, we show that the constitutively expressed, pre-existing hsp 73 rapidly forms a stable complex with the newly synthesized stress inducible hsp 72. As is demonstrated by double-label indirect immunofluorescence, both proteins exhibit a coincident locale within the cell. Moreover, injection of antibodies specific to hsp 73 into living cells effectively blocks the ability of both hsp 73 and hsp 72 to redistribute from the cytoplasm into the nucleus and nucleolus after heat shock. These results are discussed as they relate to the possible structure and function of the constitutive (hsp 73) and highly stress inducible (hsp 72) forms of hsp 70, both within the normal cell as well as in the cell experiencing stress.

Adenosine Triphosphate↗

Association of interleukin-6 in the pathogenesis of acutely fatal SIVsmm/PBj-14 in pigtailed macaques.

Infection with a variant of simian immunodeficiency virus (SIVsmm/PBj-14) causes death in juvenile pigtailed macaques within 8 days of infection. The primary pathology is localized to the lymphoid tissues of the gut and spleen. Although the virus is present, the lesions are most consistent with acute reactive inflammation. We studied the serum and tissues for evidence of acute cytokine production often associated with acute inflammation. One factor, IL-6, was found to be significantly increased (> 1000-fold) over all other measured cytokines in all the pigtailed macaques who died acutely. Increased levels of IL-6 were found both in the serum and in the inflamed tissues. mRNA for IL-6 was found in the tissues with the highest protein levels of IL-6. The marked increase in IL-6 and IL-6 mRNA correlated with the virus levels in the tissues and serum as determined by viral isolation, immunohistochemistry, and Northern blot analysis. These findings suggest that the underlying pathogenesis of primary tissue damage, necrosis, and death by PBj-14 is the induction of cytokine production. Although the presence of the virus may be critical for the initiation of these events, the intense inflammatory reaction is associated with the cause of death.

Animals↗

Increased tachykinin receptor gene expression in asthmatic lung and its modulation by steroids.

Substance P has several inflammatory effects on the airways mediated via neurokinin 1 receptors (NK1Rs) and, if released from sensory nerves, may amplify the chronic inflammation seen in asthma. Northern blot analysis of NK1R mRNA in lung showed a 52 +/- 10% (S.E.M.; P < 0.01) increase in mRNA in the asthmatic lung compared with non-asthmatic control tissue. NK1R mRNA was reduced by 84.5 +/- 1.9% after incubation with dexamethasone (1 microM) for 3 h (P < 0.01). In contrast, NK2R mRNA was unaltered in asthmatic lungs and dexamethasone treatment had no effect on the level of NK2R mRNA. These results suggest that chronic inflammation in asthma may result in increased NK1R gene expression and that this effect is reversed by glucocorticosteroids.

Adolescent↗

Colposcopy to establish physical findings in rape victims.

OBJECTIVE: Conventional rape examination protocols have been poor in yielding genital findings (10% to 30% typically). We report our experience with a revised protocol employing colposcopy to perform genital examinations of victims and to document findings. STUDY DESIGN: Physical examinations were performed on rape victims seen by San Luis Obispo County's Suspected Abuse Response Team between 1985 and 1990, and the results were reviewed for this study. RESULTS: Of 131 patients seen within 48 hours and who experienced penile penetration, 114 (87%) had positive findings. Colposcopic magnification allowed examiners to characterize these findings as acute mounting injuries, typically seen at 3, 6, and 9 o'clock on the posterior fourchette and consisting chiefly of lacerations, ecchymosis, and swelling. CONCLUSIONS: An examination protocol that includes colposcopy may be the most reliable means to document and characterize genital findings in rape victims and to evaluate whether findings may be linked to a reported sexual assault.

Colposcopy↗

Pathologic changes induced by phospholipase A2 isolated from the venom of Collett's snake, Pseudechis colletti: a light and electron microscopic study.

Pseudechis colletti is an Australian elapid snake with a range limited to central Queensland, Australia. The venom of this snake, as well as that of several other Australian elapids, has been shown to contain a phospholipase A2 (PLA2) which can cause a marked myoglobinuria in mice. Few studies have described the histopathologic and ultrastructural changes that result from myotoxic PLA2-induced damage. Our investigation demonstrated that the isolated PLA2 induced myodegeneration and necrosis in myocardium in a dose-related manner, with subsequent myoglobinuria and myoglobinuric nephropathy.

Animals↗

Effects of caffeine with repeated dosing.

We have recently demonstrated dose-dependency of caffeine metabolism under multiple dosing conditions. Whether there are persistent pharmacodynamic actions of caffeine under such circumstances is the focus of this report. Nine healthy subjects were given, in randomized 5 day blocks, placebo, 4.2 (low) and 12 (high) mg.kg-1.day-1 of caffeine in 6 divided doses. After 5 days, complete tolerance developed to the effects of caffeine on blood pressure, heart rate and plasma glucose concentrations. The 24-h area under the curve (AUC) for plasma norepinephrine and the AUC for the total sum of free fatty acids (FFA) both demonstrated a trend to increase with the high dose caffeine treatment. When the AUC for norepinephrine was split into 12 h time periods, a significant difference between the placebo and the high dose treatment block was seen. We conclude that regular consumption of 12 mg.kg-1 of caffeine per day (equivalent to approximately 6 to 11 cups of coffee per day) may produce pharmacodynamic effects not completely compensated for by the development of tolerance. Mechanisms of tolerance may be overwhelmed by the nonlinear accumulation of caffeine and other methylxanthines in the body when caffeine metabolism becomes saturable.

Adult↗

Cervical findings in rape victims.

The difficulty of documenting genital findings in rape victims by gross visualization is well known. However, we report two cases in which cervical findings were readily established by colposcopic examination and photography. Use of the colposcope may significantly increase the reliability of establishing findings in rape victims.

Adolescent↗

The efficacy of ultrasonic pest controllers for fleas and ticks.

Two ultrasonic pest controllers, a pet-collar unit and a large unit for household use, were tested for their efficacy in repelling fleas and ticks in a choice chamber. Neither unit had any affect on the distribution of fleas or ticks in the choice chamber up to 24 h exposure, and activity of fleas, ticks and cockroaches was unimpaired. The study extends and supports previous findings that ultrasound is ineffective as a means of controlling common pests of households and pets.

Animals↗

Class I MHC genes and CD8+ T cells determine cyst number in Toxoplasma gondii infection.

To determine roles of MHC class I and II genes in protection against Toxoplasma gondii, H-2 congenic and mutant mice were infected perorally with bradyzoites of T. gondii and brain cysts were enumerated 30 days later. As B10 mice (H-2b) are cyst susceptible and B10.A mice (H-2a) are cyst resistant, B10 congenic mice having the same alleles but different H-2 haplotypes were used to locate the controlling gene. Genes located at H-2L (i.e., class I genes) were found to regulate the number of brain cysts which form following peroral infection with T. gondii (p less than 0.001) with Ld being resistant and Lb being susceptible. The regulatory function of the H-2L gene product was confirmed through the study of D mutant (dm) mice. B10.D2-H-2dm1 (dm1) mice have a gain-loss mutation in Dd and Ld (i.e., recombination of Ld and Dd) and BALB/c-H-2dm2 (dm2) mice have a deletion of the Ld gene. Both these dm strains were cyst susceptible (p less than 0.001). These results provide the first direct evidence that class I genes regulate numbers of T. gondii cysts that form. In vivo ablation of CD8+ T cells with mAb YTS 169.4 converted cyst resistant B10.BAR12 mice to cyst susceptible. This result is consistent with a role for MHC restricted CD8+ cytotoxic (or suppressor) T cell regulation of cyst formation. A mutation in Ia in B6.C-H-2bm12 (bm12) mice amplified cyst numbers in susceptible mice, which is consistent with the importance of helper/inducer T cells in the induction of cytotoxic T cells. These findings are relevant to understanding the complex immunologic mechanisms that protect against T. gondii infection, development of protective preparations, and provide a conceptual basis for determining whether similar immunogenetic regulation of susceptibility is also operative in humans.

Animals↗

Rheumatologic manifestations of malignancy.

The relationship between rheumatologic syndromes and cancer covers a very broad array of both common and distinctly rare manifestations. This discussion has outlined some of the known relationships that do exist. A high index of suspicion by both the primary care physician and subspecialist will enhance the probability of detecting cancer in the patient who may present with rheumatologic complaints.

Adenocarcinoma↗