Lisa M. Gibbs

Propofol and Barbiturate Depression of Spinal Nociceptive Neurotransmission

Barbiturates are often described as non-analgesic or even hyperalgesic agents; the newer intravenous anesthetic agent propofol is said to be non-analgesic. Both propofol and barbiturates occupy sites on the GABAA receptor. The present study was designed to compare the effects of propofol and barbiturates on nociceptive-related neurotransmission in neonatal rat spinal cord; to search for actions that might be hyperalgesic; and to determine the extent to which propofol depression of nociceptive neurotransmission is mediated by GABAA receptors. The monosynaptic reflex, a slow ventral root potential (slow VRP) and the dorsal root potential (DRP) were recorded from isolated neonatal (1-5 days old) superfused rat spinal cords in response to electrical stimulation of a lumbar dorsal root. The slow VRP and the DRP are related to nociception. Propofol (0.5-10 microM), pentobarbital (1-10 microM), and thiopental (1-10 microM) reversibly depressed the slow VRP. Dose-response curves were monophasic and linear over this range. The monosynaptic reflex was unaffected. The GABAA agonist muscimol (0.2-1 microM) also depressed the slow VRP. Propofol and barbiturate slow VRP depression was antagonized by the GABAA antagonist bicuculline (1 microM). Propofol depressed the response evoked by direct application of substance P. The DRP is a GABAA-mediated depolarization of primary afferent nerve terminals that diminishes the effectiveness of nociceptive input. Propofol and thiopental increased electrically evoked DRP amplitude and increased the DRP evoked by application of muscimol. Both propofol and barbiturates thus depressed the nociceptive-related slow VRP and enhanced the antinociceptive DRP; their effective concentrations are at or close to the general anesthetic range for these agents. No anti-analgesic or hyperalgesic effect was observed. (ABSTRACT TRUNCATED AT 250 WORDS)

Screening for abuse and neglect of people with dementia

OBJECTIVE: To investigate characteristics of people with dementia and their caregivers (CGs) that are associated with mistreatment in order to inform clinicians about screening for mistreatment.

Bruising as a Marker of Physical Elder Abuse

OBJECTIVES: To describe bruising as a marker of physical elder abuse.

Correlates of anesthetic properties in isolated spinal cord: cyclobutanes

Two halogenated cyclobutanes, one anesthetic and one not, were compared on receptor-specific pathways in isolated neonatal rat spinal cord. The anesthetic 1-chloro-1,2,2-trifluorocyclobutane depressed the monosynaptic reflex (glutamate non-NMDA receptors) and abolished a slow ventral root potential (glutamate NMDA, non-NMDA and tachykinin receptors). This compound slightly enhanced the muscimol-evoked dorsal root potential (GABAA) but reversibly depressed the dorsal root potential elicited by dorsal root stimulation. The non-anesthetic 1,2-dichlorohexafluorocyclobutane increased monosynaptic reflex, depressed slow ventral root potential approximately 50%, had little effect on muscimol-evoked dorsal root potential, and irreversibly depressed dorsal root-evoked dorsal root potential. Hypoxia accounts for slow ventral root potential depression, but not monosynaptic reflex enhancement. In this preparation and for this pair of compounds, anesthetic properties are related to blockade of transmission at glutamate synapses, with a small component of GABAA enhancement. Monosynaptic reflex increase may be related to the non-anesthetic cyclobutanes convulsant and anti-anesthetic properties.

Substance P and NMDA receptor-mediated slow potentials in neonatal rat spinal cord : age-related changes

Slow ventral root potentials (slow VRPs) recorded from 1- to 5-day-old rat spinal cords are implicated in nociception, but there is controversy over their origin and persistence in the adult. The present study investigated changes in the role of substance P and NMDA receptors in slow VRP generation during the postnatal period (1-21 days). Through 9 days, dorsal root stimulation elicits slow VRPs with typical peak amplitudes at 3-4 s, decay time constants of 18-20 s, and durations > 20 s. After 11 days, peak amplitude shortens to < 1 s, decay time constant 4-5 s, and duration < 10 s. At 1-6 days, slow VRPs are sensitive to the NMDA receptor antagonist APV and the substance P antagonists spantide and CP 96,345. After 11 days, APV sensitivity is retained, but spantide and ability of substance P to evoke a response are diminished. Abbreviated slow VRPs in post-11-day spinal cords appear to correspond to the early APV-sensitive component of long-duration slow VRPs in younger animals. Attempts to restore long-duration slow VRPs in 12- to 14-day-old rat cords by blocking various inhibitory mechanisms were not successful. The results suggest that a substance P response, some of which is mediated by NK1 receptors, is lost with maturation of the cord. Either a developmental role played by substance P changes with maturity, or the motor neurons of the isolated post-11-day cord lose the capacity to sustain large long-duration plateau potentials.

Understanding the Medical Markers of Elder Abuse and Neglect: Physical Examination Findings

A specific foundation of knowledge is important for evaluating potential abuse from physical findings in the older adult. The standard physical examination is a foundation for detecting many types of abuse. An understanding of traumatic injuries, including patterns of injury, is important for health care providers, and inclusion of elder abuse in the differential diagnosis of patient care is essential. One must possess the skills needed to piece the history, including functional capabilities, and physical findings together. Armed with this skill set, health care providers will develop the confidence needed to identify and intervene in cases of elder abuse.

Descending inhibition in neonatal rat spinal cord: Actions of pentobarbital and morphine

Descending inhibition plays an important role in modulating spinal nociceptive neurotransmission. Barbiturates have been suggested to be poor analgesics or anti-analgesic because they block descending inhibition from supraspinal centers to the spinal cord. Opiate analgesics, on the other hand, are postulated to increase descending inhibition. We tested this hypothesis in an isolated brain stem-spinal cord preparation from neonatal rats, using as the test response a nociceptive-related slow ventral root potential (sVRP) recorded in the lumbar region. Brain stem and spinal cord were separately perfused. Transecting the spinal cord, applying the local anesthetic lidocaine to the brain stem, or cooling the brain stem increased the area of the sVRP, thus demonstrating that tonic descending inhibition is present in this preparation. Pentobarbital (Pb) (1-10 microM) applied to the spinal cord depressed the sVRP in a dose-dependent fashion. Spinal cord transection did not significantly change Pb potency. Pb (5-10 microM) applied to the brain stem alone did not significantly increase sVRP amplitude. Morphine (15-35 nM) applied to the spinal cord also depressed the sVRP but had no effect when applied to the brain stem. The results show that there are functional synaptic connections mediating tonic descending inhibition in the neonatal rat. They do not support interaction with tonic descending inhibition as an explanation for morphine analgesia or as a reason for lack of analgesic properties in the barbiturates.

Variability in Findings From Adult Protective Services Investigations of Elder Abuse in California

Adult Protective Services (APS) workers in California investigate complaints of elder abuse and must determine the validity of a complaint with minimal guidelines. It is unclear whether APS workers reach similar conclusions given cases with similar circumstances. To assess variation in case findings and reasons for them, we used data from monthly reports of completed investigations, and investigation outcomes from all 58 California counties from September 2004 to August 2005, telephone interviews with 54 of 58 counties, and site visits to 17 counties. We also compared the data from 2004–2005 with more recent data from 2013. Large variability was found from county to county in the proportions of cases found to be conclusive, inconclusive, and unfounded. The combined analyses revealed significant differences in how individual APS workers interpret definitions of different types of case outcomes, varying skill and experience of the APS workers, individual and county agency factors, and other reasons that influence variability in case findings. Widespread inconsistencies in the outcomes of elder abuse investigations raise issues to be addressed on multiple levels, including the use of APS data for developing policy, standardizing training of APS workers, and seeking just outcomes for the victims of elder abuse.

Prevalence of Frailty and Factors Associated with Frailty in Individuals Aged 90 and Older: The 90+ Study.

To evaluate the prevalence of frailty and examine factors associated with frailty in the 90+ Study.

Care of the Victim

The number of elder abuse cases is expected to rise as the number of persons older than age 65 doubles over the next 20 years. Patients affected by elder abuse present in all care settings, including inpatient and outpatient clinical care, emergency rooms, long-term care facilities, and home care. Victims have significant medical consequences, physical and psychological, and often need additional resources, including legal guidance. Health care professionals need additional training to be effective advocates for survivors of elder abuse. Care of the victim must also be recognized as an equally important topic for research and education.