Dopamine-stimulated adenylate cyclase and tyrosine hydroxylase in diabetic rat retina

The effects of streptozotocin-induced diabetes on the retinal dopaminergic system have been examined in Long-Evans (pigmented) rats. Tyrosine hydroxylase activity was significantly decreased while dopamine-stimulated adenylate cyclase was increased in 2-month-diabetic rats. The observed increase in dopamine-stimulated adenylate cyclase activity in diabetic retinae may be related to neurotransmitter receptor changes because postreceptor activation of adenylate cyclase by guanylyl imidodiphosphate was not altered.     

Families and genetics: Bridging the gap between knowledge and practice

The Human Genome Project (HGP) and news of genetic breakthroughs are pervasive to most of our lives today. Yet how many of us have had formal education in genetics? When and how do we integrate this knowledge into our clinical practice? This article discusses the relevance of genetics to newborn and infant nursing practice and how new genetic knowledge affects patients and their families. Approaches to educating clinicians about genetics within the context of the family are described, as newborn and infant nurses emphasize the family in their daily work and frequently work with children and families with genetic diagnoses. Education and research from the University of Illinois at Chicago College of Nursing are used as examples to describe the integration of genetics into the practice of nurses caring for newborns, infants, and their families. Copyright 2002, Elsevier Science (USA). All rights reserved.     

Physiological Responses During Graded Treadmill Exercise in Chemical-Resistant Personal Protective Equipment

Background. As the likelihood of terrorist acts increases, prehospital personnel have been forced to train in the proper use of chemical-resistant personal protective equipment (PPE). This protective ensemble has been reported to be physiologically taxing for the wearer, imposing an additional thermal load resulting in hypohydration, hyperthermia, andreduced work time. Victim extrication, the rescue-the-rescuer role of the rapid intervention team andrapid self-extrication, typically requires high-intensity work that can be maintained only for short time intervals. The additional physiological burden imparted by the level C PPE during high-intensity work is unknown. Objective. We hypothesized that the added thermal burden resulting from work in PPE would shorten work time andresult in a higher core temperature during incremental treadmill exercise. Method. In this prospective, crossover, laboratory study, EMS providers (n = 8, 5 male) completed a Bruce treadmill test on two occasions: once in a chemical-resistant coverall andair-purifying respirator (PPE) andonce in shorts andt-shirt (CON). Oxygen consumption, vital signs, core andskin temperature, andperceptual measures of exertion, thermal sensation, andcomfort were monitored throughout the test. Results. Subjects achieved maximal oxygen consumption andmore than 90% of age-predicted maximum heart rate in both conditions. Heart rate, skin temperature, andmeasures of perceived exertion, comfort, andthermal sensation increased during the treadmill exercise but did not differ between the PPE andCON conditions. Core temperature increased in both the CON andPPE conditions (0.8 ± 0.5 vs. 0.7 ± 0.3, p = 0.40). Conclusion. High-intensity work in level C PPE is primarily limited by cardiovascular capacity. The thermal burden associated with this short bout of work in PPE (approximately 10 minutes) is not different than high-intensity work in short pants andcotton t-shirt. Consideration should be given to cardiorespiratory fitness when assigning providers to work in chemical-resistant PPE, especially on tasks that require high-intensity work.     

Characterization of the Atmosphere within Vapor-Resistant Encapsulating Personal Protective Equipment during Treadmill Exercise

Background. Hazardous materials technicians may be required to wear fully encapsulated vapor-resistant (Level A) personal protective equipment (PPE) to contain and mitigate a hazardous materials emergency. It is commonly taught and practiced in hazardous material technician courses that if the wearer's self-contained breathing apparatus (SCBA) fails, the technician can remove the SCBA face piece and breathe the in-suit expired air while exiting the incident or awaiting rescue. Objective. To determine the composition of expired air present within an encapsulating suit during exercise. Methods. Subjects (n = 4) walked on a motor-driven treadmill (3.2 km·h^–1) for 30 minutes while wearing encapsulating PPE and SCBA. Oxygen (O₂) and carbon dioxide (CO₂) levels within the PPE were monitored. Subject vital signs and end-tidal CO₂ (EtCO₂) were continuously monitored. After treadmill exercise, rescue air from an external source was introduced into the suit. Results. Mean oxygen levels inside the PPE fell below the Occupational Safety and Health Administration (OSHA) definition of oxygen-deficient environment (< 19.5% O₂) after 2 minutes of treadmill walking and were below 17% at the end of 30 minutes. Carbon dioxide levels inside the PPE exceeded 3% in all subjects by the end of the exercise protocol. Rapid return to a room-air composition of oxygen and CO₂ within the suit was accomplished with introduction of positive-pressure air from an alternate external air source. Conclusion. A toxic atmosphere is rapidly created within fully encapsulating PPE during treadmill exercise of moderate intensity. Breathing the expired air within the PPE cannot be recommended during technician training. Application of an external air source to flush the suit can return the PPE atmosphere to safe limits, but requires an intentional suit breach to accomplish.