An exploratory spatial contaminant assessment for polar bear (Ursus maritimus) liver, fat, and muscle from northern Canada.

Since the industrial era, chemicals have been ubiquitous in worldwide ecosystems. Despite the discontinued release of highly toxic persistent organic pollutants (POPs) in the environment, the levels of some POPs are still being measured in the Canadian Arctic. These contaminants are of great concern due to their persistence, toxicity, and levels of bioaccumulation in food chains. Animals occupying top trophic positions in the Canadian Arctic, particularly polar bears, are exposed to these contaminants mainly through their diet. Our study investigated the levels of 30 metals (including total and methyl mercury) alkaline and alkaline earth metals, 15 polycyclic aromatic compounds and their alkyl congeners (PACs), 6 chlordanes (CHLs), and 20 polychlorinated biphenyls (PCBs), in 49 polar bears from the Canadian Arctic. Contaminant burden was measured in liver, muscle, and fat in bears of different sex, age, and locations. A principal component analysis did not distinguish differences between age and sex profiles for most contaminants. However, the concentrations measured and their distribution in the tissues confirm findings observed in past studies. This study highlights the importance of continual monitoring of polar bear health (e.g., newly detected PACs were measured within this study) and evaluating those impacts for the next generations of polar bears.

Instability of the neonatal hip: the role of early or late splintage.

From January 1992 to December 1997, 59 dislocatable hips (37 children), confirmed by ultrasound, were splinted by Pavlik bracing within 2 weeks of birth. The majority were splinted within 1 week. From January 1998 to December 1999, 16 dislocatable hips (11 children) were evaluated by ultrasound and were not initially splinted but were followed up by serial ultrasound. They were splinted if they did not spontaneously stabilise on ultrasound. None of those patients treated by immediate splintage between 1992 and 1997 have subsequently required surgical intervention. Two of the infants treated between 1998 and 1999 (12% of the hips) later required a surgical procedure on the hip joint or proximal femur (p=0.049, Fisher's exact test). Nine out of 16 hips required splintage at a later date. We would not advocate delayed observation by ultrasound of unstable hips after 2 weeks of age. A clinically unstable hip should be assessed by ultrasound within 2 weeks of birth. If it is unstable on ultrasound, it should be splinted for 6 weeks. There is no need to wean off the splint.

Improvement in the treatment of stable ankle fractures: an audit based approach.

Stable ankle fracture patients form a distinct, clinically benign group in which functional treatment can be used. An initial retrospective audit of the fracture clinic records of our institution for 1 calendar year demonstrated that recognition and functional treatment of stable ankle fractures was rarely followed. After the introduction of formal departmental evidence-based guidelines, subsequent audits have showed progressive improvements with significant reductions of time spent immobilised in plaster, time spent non-weight bearing and number of routine check radiographs, without compromising patient safety. This study illustrates the value of evidence-based guidelines in maintaining high standards of care over time.

The use of electronic mail at the reference desk: impact of a computer-mediated communication technology on librarian-client interactions.

Commonly recognized computer-mediated communication (CMC) tools include virtual environments, bibliographic databases, listservers, newsgroups, group teleconferencing, interactive messaging systems and electronic mail. The use of these technologies in libraries has grown exponentially over the past decade. Electronic mail has emerged as an especially popular communication tool for librarians, and their colleagues and patrons. This paper explores the use of a reference department electronic mail service and its impact on reference services and librarian-client interactions. Several issues related to the implementation of CMC technologies are presented, including the maintenance and monitoring of reference electronic mail systems, the types of questions that are typically posted, and potential barriers to the implementation and use of reference e-mail.

Changes in the amplitude of the nasal cycle associated with symptoms of acute upper respiratory tract infection.

Nasal airflow is normally asymmetrical and subject to spontaneous reciprocal changes which are often referred to as the 'nasal cycle'. The nature of these spontaneous changes in nasal resistance is poorly understood and little information is available about how they are affected by nasal disease. In order to understand the changes in nasal resistance in health and disease it is important to record unilateral resistance rather than express results as total nasal resistance. Unilateral resistance is subject to continuous reciprocal changes and therefore new measurements were developed in this study in order to quantify the nasal resistance of each nasal passage. Twelve human subjects (age 19-38) with symptoms of acute respiratory tract infection (URTI) were recruited for the study which involved serial measurements of unilateral nasal airway resistance using the technique of posterior rhinomanometry over a period of six hours. Measurements were made on one day when subjects had symptoms of URTI and then repeated 6-8 weeks later when subjects were healthy. The results of this study show that all of the subjects exhibited spontaneous reciprocal changes in nasal airway resistance on both study days but that there was a significant increase in the amplitude of the changes in resistance when the subjects had symptoms of URTI with one nasal passage often becoming severely congested. In order to quantify the amplitude of the reciprocal changes in nasal resistance two new measures were used. The minimum and maximum nasal airway resistance recorded for each nasal passage during the six hour recording period (MIN NAR and MAX NAR). Mean MIN NAR with URTI was 0.4 Pa cm3s +/- 0.07 which was not significantly different from mean MIN NAR in health which was 0.36 Pa cm3s +/- 0.05 (p = 0.22, n = 20). The mean MAX NAR during URTI was 2.44 Pa cm3s +/- 0.38 and this decreased significantly to 1.36 +/- 0.17 when recorded during healthy conditions (p = 0.01, n = 20). The increased amplitude of spontaneous reciprocal changes in nasal airway resistance associated with symptoms of URTI is proposed to be due to an increased filling pressure to the nasal venous sinusoids associated with a nasal inflammatory response. A model is proposed to explain the role of the nasal sympathetic vasoconstrictor tone and nasal venous filling pressure in the control of nasal airway resistance and to help explain the periods of unilateral nasal obstruction often associated with allergic and infective rhinitis.

Asymmetry in the autonomic nervous system with reference to the nasal cycle, migraine, anisocoria and Menière's syndrome.

Studies on the nasal cycle have demonstrated that the autonomic tone to the nose is asymmetrical and oscillates in a regular cycle. Autonomic tone may be regulated from a centre in the hypothalamus and normally there is a balance between he autonomic tone of the right and left halves of the body. However, under stress or with hypothalamic instability this balance may be disrupted and result in the marked autonomic asymmetry seen in migraine or Meniér's syndrome. Research on the nasal cycle in conditions where autonomic asymmetry is apparent could change the entire concept of autonomic control.

Sympathetic innervation of the nasal mucosa of the pig.

Nasal disorders such as atrophic rhinitis in the pig are widespread and are of economic importance in livestock production. A better understanding of the basic physiology of the nasal mucosa could help in the study and treatment of nasal disorders. This paper presents a simple method which may prove useful in studies on the autonomic innervation of the nasal blood vessels. The results demonstrate the great sensitivity of the nasal blood vessels to sympathetic activity and indicate that there may be a vascular connection between the two nasal passages.