Development and validation of an automated, enzyme-mediated colorimetric assay of salicylate in serum

This salicylate-specific assay can be adapted for use with most discrete analyzers, for rapid emergency or routine testing with small serum or plasma sample volumes and a single calibration. The basis of this method is as follows: salicylate monooxygenase (EC 1.14.13.1) converts salicylate to catechol in the presence of NADH; the catechol then reacts with 4-aminophenazone under alkaline conditions, catalyzed by manganese ions, to produce a red dye. Incorporation of an NADH-regenerating system, involving glucose and glucose dehydrogenase, into the enzyme reagent ensures that the working reagent is stable for more than two weeks. The standard curve is linear over the drug concentration range 0 to 5 mmol/L. The CV was less than 4% over 20 days. Results correlated well with those by the Trinder colorimetric method and an HPLC method. We saw no interference by any of 80 drugs we tested at therapeutic concentrations or by endogenous compounds in serum.     

Living with lifting: mothers' perceptions of lifting and back strain in childcare

The methods a mother selects to physically care for her young children may subject her to back strain or injury depending on the methods she selects. Little is known about what motivates mothers to select particular child‐care methods and equipment. The aim of this qualitative study was to explore the choices mothers of young children make in this area and their experiences using the methods they select. Nine mothers completed a brief questionnaire and participated in a semi‐structured interview. Analysis of the data revealed a number of motivating factors that were considered before making a final decision on what method to use. Rarely were issues related to posture and back care considered. Primarily, mothers chose methods based on what was best for the child, without consideration of their own needs. Consideration of the effect of a method on their back was given only when they experienced back strain. Further research is required to investigate the best methods for lifting and handling young children while providing maximum protection for the mothers' backs. Copyright © 2000 Whurr Publishers Ltd.     

Characterizing the phenomenon of radiation recall dermatitis.

Radiation recall represents the 'recalling' of an effect similar in appearance to that of an acute radiation reaction in a previously irradiated field. The recall is triggered by the administration of certain drugs days to years after the exposure to ionizing radiation. This review focuses almost exclusively on the skin manifestations of radiation recall to assemble the largest data base upon which to discuss this rare phenomenon. No absolute radiation dose threshold is apparent, but rather an interplay between dose and time before drug exposure seems to affect both the risk and speed of onset of recall. Recall usually occurs on first exposure to a particular recall-triggering drug. The skin reaction develops within minutes to days. The time to develop the reaction may be slightly longer for oral than intravenously administered drugs reflecting their bioavailability. Most drugs associated with recall are cytotoxics, but several other drugs may elicit the phenomenon. Individuals exposed to a number of potentially recall-triggering drugs reveal the marked drug specificity characteristic of the phenomenon. Skin reactions usually settle within a few days of stopping the triggering drug. The role of steroids or anti-histamines in affecting resolution is unclear. Drug rechallenge tends to produce either only a mild recurrence or no recurrence of recall. Steroids or dose reduction may favour uneventful rechallenge. A number of aetiological hypotheses on radiation recall exist. Using the available evidence these hypotheses are critically reviewed and a novel hypothesis based on radiation affecting local cutaneous immunological responses proposed.     

The role of adjuvant chemotherapy in the treatment of advanced head and neck cancer

The role of chemotherapy in the multidisciplinary treatment of advanced squamous cell carcinoma of the head and neck remains to be defined. Uncontrolled adjuvant studies integrating chemotherapy with local therapies utilizing a 'sequential' or 'simultaneous' strategy have indicated that high response rates to initial chemotherapy and high complete remission rates are achievable. Both these factors appear to predict for improved survival. Unfortunately results of randomized, controlled studies generally have not confirmed any major overall survival advantage. However, these trials clearly failed to utilize optimal therapies: suboptimal trials yield suboptimal results. Encouraging data from large uncontrolled studies have now provided critical information regarding optimal trial design; a) Since primary tumor site has proved a significant predictive factor for response to treatment and survival, future trials must include sufficient numbers of patients for detailed site-by-site analyses, and b) radical surgery may be omitted without compromising survival by using initial chemotherapy followed by radiotherapy for advanced laryngeal cancer.     

Differences in oral health status between institutionalized and non-institutionalized older adults

Differences in oral health status between independent and institutionalized adults have been difficult to interpret because the latter population is typically older and has a higher proportion of women, confounding any association between institutionalization and disease levels. We undertook an analysis of oral disease amongst institutionalized (n = 149) and non-institutionalized (n = 246) samples of older adults randomly selected from the population in East York, Ontario. When the confounding effects of age and gender were controlled by constructing 67 matched pairs, institutionalized people were more than twice as likely to be edentulous (OR = 2.17, 95% CI = 1.09-4.29). This association was confirmed using data from all subjects in a logistic regression model. Analysis of covariance of data from dentate subjects revealed that the institutionalized seniors had fewer filled teeth (P less than 0.05, controlling for age and sex), but there were no statistically significant differences in the number of teeth which were missing, decayed, or requiring extraction. These findings suggest that antecedent, sociodemographic factors prior to institutionalization are responsible for the higher probability of oral disease in this group of older adults.     

Pharmacokinetics and radiation dosimetry of 18F-fluorocholine.

18F-Fluorocholine (fluoromethyl-dimethyl-2-hydroxyethylammonium [FCH]) has been developed as an oncologic probe for PET. This study evaluates the kinetics and radiation dosimetry of 18F-FCH using murine and human biodistribution data. METHODS: The biodistribution of 18F-FCH was obtained at time points up to 10 h after administration in control and tumor-bearing anesthetized nude mice. Human biodistribution data within the first hour after injection were obtained from attenuation-corrected whole-body PET scans of male (n = 7) and female (n = 5) cancer patients. Radiation dosimetry estimates were calculated using the murine and human biodistribution data assuming no redistribution of tracer after 1 h. RESULTS: Rapid pharmacokinetics were observed for 18F-FCH in mice and humans. The biodistribution is nearly static after 10 min. The dose-critical organ is the kidney, which receives 0.17 +/- 0.05 and 0.16 +/- 0.07 mSv/MBq (0.64 +/- 0.18 and 0.55 +/- 0.32 rad/mCi) for females and males, respectively. The effective dose equivalent (whole body) from administration of 4.07 MBq/kg (0.110 mCi/kg) is approximately 0.01 Sv for females and males. CONCLUSION: 18F-FCH is rapidly cleared from the circulation and its biodistribution changes very slowly at >10 min after administration. The kidney is the dose-critical organ and limits administration levels of 18F-FCH to 4.07 MBq/kg (0.110 mCi/kg) in human research studies.     

Evidence that substance P selectively modulates C-fiber-evoked discharges of dorsal horn nociceptive neurons.

Previous studies suggest that the undecapeptide substance P (SP) functions as a primary afferent neurotransmitter or neuromodulator of nociception which may mediate the slow temporal summation ('windup') of discharges of dorsal horn nociceptive neurons elicited by repetitive stimulation of C-afferents. The present study tested this hypothesis by investigating the effects of local spinal application of SP and an SP antagonist. [D-Pro2,D-Trp7,9]-SP (DPDT), on A- and C-fiber-evoked firing of dorsal horn neurons in an intact, urethane-anesthetized rat preparation. Extracellular single unit recordings from both wide dynamic range and nociceptive specific neurons during controlled repetitive electrical stimulation of the ipsilateral hind paw indicated that SP enhanced C-evoked firing in an apparent dose-related manner (100 greater than 20 = 4 nmol), whereas DPDT inhibited C-evoked discharges with an apparent bell-shaped dose-response (20 greater than 100 = 4 nmol). Neither agent significantly altered either A-evoked or spontaneous activity. In agreement with previous investigators, morphine sulfate also selectively inhibited C-fiber-evoked firing without altering A-fiber-mediated activity, validating the selectivity of our system. These findings provide additional evidence that SP functions as a neuromodulator of primary afferent nociception, and further suggest that the effects of SP are selective to nociceptive transmission mediated by C-fibers.