Sensitivity of mottled sculpins (Cottus bairdi) and rainbow trout (Onchorhynchus mykiss) to acute and chronic toxicity of cadmium, copper, and zinc

Studies of fish communities of streams draining mining areas suggest that sculpins (Cottus spp.) may be more sensitive than salmonids to adverse effects of metals. We compared the toxicity of zinc, copper, and cadmium to mottled sculpin (C. bairdi) and rainbow trout (Onchorhynchus mykiss) in laboratory toxicity tests. Acute (96-h) and early life-stage chronic (21- or 28-d) toxicity tests were conducted with rainbow trout and with mottled sculpins from populations in Minnesota and Missouri, USA, in diluted well water (hardness = 100 mg/L as CaCO3). Acute and chronic toxicity of metals to newly hatched and swim-up stages of mottled sculpins differed between the two source populations. Differences between populations were greatest for copper, with chronic toxicity values (ChV = geometric mean of lowest-observed-effect concentration and no-observed-effect concentration) of 4.4 microg/L for Missouri sculpins and 37 microg/L for Minnesota sculpins. Cadmium toxicity followed a similar trend, but differences between sculpin populations were less marked, with ChVs of 1.1 microg/L (Missouri) and 1.9 microg/L (Minnesota). Conversely, zinc was more toxic to Minnesota sculpins (ChV = 75 microg/L) than Missouri sculpins (chronic ChV = 219 microg/L). Species-average acute and chronic toxicity values for mottled sculpins were similar to or lower than those for rainbow trout and indicated that mottled sculpins were among the most sensitive aquatic species to toxicity of all three metals. Our results indicate that current acute and chronic water quality criteria for cadmium, copper, and zinc adequately protect rainbow trout but may not adequately protect some populations of mottled sculpins. Proposed water quality criteria for copper based on the biotic ligand model would be protective of both sculpin populations tested.     

Ethical aspects of placebo in migraine research

Randomized placebo-controlled clinical trials have been the 'golden standard' during the last decades in the development of new drug therapies. This scientifically valid approach has recently been questioned in the fifth revised version of the Declaration of Helsinki, which states that the use of placebo-controlled clinical trials is only acceptable when no proven treatment exists for the studied disease. The World Medical Association further claims that no national ethical, legal or regulatory requirements should be allowed to reduce or eliminate any of the statements in the declaration. In spite of this, the document is not generally accepted as the world ethical standard, as demonstrated by its lack of adoption by many professional associations. In the evaluation process for a drug to be approved in many countries today, clinical investigators at the hospitals and researchers at the pharmaceutical companies are obliged to use study protocols that would be rejected if the new declaration were to be fully adopted. Adherence to the clinical trial guidelines of the International Headache Society could also mean violation of the new Helsinki declaration of ethics. Some ethics committees have already adopted the new declaration, which has caused concern among clinical investigators, who find this document to be vastly out of the line with common practice. At the moment, the situation is unclear and debated with increasing polarity concerning the scientific and ethical issues regarding the use of placebo in clinical trials.     

Bactericidal activity of ramoplanin against antibiotic-resistant enterococci.

Ramoplanin, a new lipoglycodepsipeptide antibiotic, was uniformly active against 65 strains of enterococci, including strains highly resistant to vancomycin, penicillin G, and gentamicin. MBCs were usually within a fourfold dilution of the MICs. In time-kill studies, ramoplanin alone demonstrated dose-dependent bactericidal activity against enterococcal strains that resisted killing by vancomycin or penicillin in combination with gentamicin.     

Therapeutic results of 5-fluorouracil in multiple and unresectable facial carcinoma secondary to xeroderma pigmentosum

A prospective study was done to test the efficacy of 5-fluorouracil (topical and systemic) in multiple and unresectable histologically proven facial squamous cell carcinomas (SCC) secondary to XP. Twelve patients (7M/5F, mean age 19.8 years) with multiple facial SCC were treated between 1994 and 1997. 5-FU was used as a twice-a-day local application in the documented areas, by continuous infusion associated with cisplatin (2 patients) and short infusion combined with folic acid (3 patients). Evaluation was done by clinical examination every two months for topical therapy and after every cycle for systemic treatment. Median treatment duration was 12 months (2 to 36 months). Treatment was well tolerated excluding episodes of pruritus in the treated areas. We observed mainly superficial tumour regression followed by dryness and crusting. In 5 cases, we performed biopsies after treatment showing in one case an extensive fibrosis with absence of tumour. However in the remaining 4 cases, despite a superficial reduction of tumour and a reconstitution of the epidermis, viable and unmodified squamous cell carcinoma remained in the deeper dermis. In the 5 patients treated by systemic 5-FU, we observed 1 complete response and 3 partial responses. Despite a dissociation between a good cosmetic result and a relatively superficial effect, topical 5-FU represents a useful therapeutic option in multiple unresectable facial SCC in patients with XP. Systemic chemotherapy is recommended in the event of more extended or profound lesions.     

First molecular detection of Theileria luwenshuni from goats in Myanmar

Parasitology Research - Tick-borne intracellular protozoan parasites of the Theileria genus infect a wide range of both domestic and wild animals. In the present study, we describe the first PCR...     

Factors contributing to hospital readmission in a Hong Kong regional hospital: a case-controlled study

BACKGROUND: As many as 50% of total hospital admissions are readmissions. Because the factors contributing to hospital readmission are multiple, and research findings are not conclusive, it is important for clinicians to gain an understanding of the key factors that contribute to readmission. OBJECTIVES:This study explores the factors contributing to hospital readmission and derives an explanatory model that can best identify characteristics of patients at high risk for hospital readmission. METHODS: This research was a case-controlled study with readmitted patients (n = 168) as the readmitted group and non-readmitted patients (n = 98) as the control group. The variables included demographic data, health assessment data, medical diagnosis, frequency of admissions, severity of illness, intensity of service and improvement of condition. The study sample was also interviewed to explore the patients' views on their repeated hospitalization. RESULTS: In the bivariate analysis significant differences between the study and control groups were multiple and generally consistent with findings in other studies. Using multiple logistic regression, however, the final model shows that only three factors best predict readmissions: frequency (3-4 times) of readmissions (OR = 9.96, p < .0001) and frequency (more than 5 times) of readmissions (OR = 15.73, p < .0001), financial assistance (OR = 5.03, p < .001), and severity of illness (OR = 3.12, p < .01). Our interview data suggest that the readmitted patients required assistance to accomplish daily living activities upon discharge and often returned to the hospital for the same health reason. CONCLUSION: The study findings suggest that patients who are frequently readmitted to the hospital are severely ill; are on public assistance; and may need special attention when discharged in order to attenuate repeated hospital readmission.     

Thyroid status and adrenergic receptor subtypes in the rat: comparison of receptor density and responsiveness

The density and functional responsiveness of adrenergic receptor subtypes were determined in tissues from control, hyperthyroid and hypothyroid rats. There was a decrease in sensitivity to isoproterenol in spontaneously beating right atria, electrically driven left atria and field-stimulated vas deferens associated with hypothyroidism, with no change in maximum response. Hyperthyroidism increased the potency of isoproterenol in right atria, but not in left atria or vas deferens. The maximal response to isoproterenol was greatly reduced in hyperthyroid left atria. The potency of procaterol, a partial agonist at beta adrenergic receptors in right atria, was unaltered in hyper- or hypothyroidism, although the maximum stimulation by procaterol was increased in hyperthyroidism. Scatchard analysis of specific [125I]pindolol binding showed that beta adrenergic receptor density was greater in hyperthyroidism than in hypothyroidism in left atria, right atria, ventricles, vas deferens and cerebral cortex, although the proportions of beta-1 and beta-2 adrenergic receptor subtypes did not change. There was no change in the responsiveness of alpha-1 adrenergic receptors mediating contraction of caudal artery and vas deferens or mediating [3H]inositol phosphate accumulation in cerebral cortex in hyperthyroid or hypothyroid rats, although the maximal contraction of caudal artery was significantly reduced in hyperthyroidism. Scatchard analysis of specific [125I]BE 2254 binding showed that alpha-1 adrenergic receptor density was significantly decreased in the ventricles from hyperthyroid rats and increased in the ventricles of hypothyroid rats, but was unchanged in vas deferens, caudal artery and cerebral cortex. Alpha-2 adrenergic receptor density in cerebral cortex, determined by Scatchard analysis of specific [3H] rauwolscine binding, was not altered in hyperthyroid or hypothyroid rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Co-expression of CYP27B1 enzyme with the 1.5kb CYP27B1 promoter-luciferase transgene in the mouse

The renal enzyme 25-hydroxyvitamin D 1alpha-hydroxylase (CYP27B1), responsible for the synthesis of circulating. 1,25-dihydroxyvitamin D (1,25D), is also expressed in a number of non-renal tissues. The regulation of CYP27B1 expression by the short flanking promoter outside the kidney is, however, largely unknown. We have used a transgenic mice expressing the 1.5kb promoter of the human CYP27B1 gene fused to the firefly luciferase gene in order to investigate tissue-specific CYP27B1 expression. These transgenic animals demonstrated co-localised luciferase and endogenous CYP27B1 expression in kidney proximal convoluted tubular cells. Strong co-expression of luciferase and CYP27B1 also occurred in neurons and Purkinje cells of the cerebellum and in Leydig and Sertoli cells of the testes. Other tissues to exhibit CYP27B1-promoter directed luciferase activity included lung, prostate, trabecular bone and jejunum as well as the choroid epithelium. The tissue specific changes in luciferase activity were age-related. These findings demonstrate that the proximal 1.5kb 5' flanking region of the CYP27B1 gene directs the expression of CYP27B1 in a number of known and novel tissues in a specific manner.