Noxious stimuli excite neurons in nucleus submedius of the normal and arthritic rat

Anatomical studies have revealed the existence of an ascending pathway originating in the spinal cord and medullary dorsal horn, relaying in nucleus submedius (Sm) in medial thalamus and terminating in ventrolateral orbital cortex. It has been suggested that this pathway may be involved in the transmission of nociceptive information. In the present study extracellular recordings were obtained from neurons in Sm of anesthetized arthritic and normal rats. Mechanical and thermal stimuli were delivered to various regions of the body to determine the types of somatic stimuli which could activate Sm neurons. Over 40% of the 146 neurons studied responded to somatic stimuli. In the normal rats only high intensity mechanical and thermal stimuli were effective in inducing responses. In the arthritic rats lower intensity mechanical stimuli, joint movements and high intensity thermal stimuli were effective. Such stimuli produce nociceptive reactions in the freely moving arthritic rat. Almost all the responses were excitatory and generally lasted the entire duration of the 15-s stimuli employed. In some cases after-discharges were present. The receptive fields of the neurons were in almost all cases large and bilateral. These findings support the hypothesis that Sm may be involved in mediating the affective-motivational aspects of pain.     

Salivary gland 99mTc-scintigraphy: a grading scale and correlation with major salivary gland flow rates

Sequential salivary gland scintigraphy with 99mTc-technetium pertechnetate (Tc-99) is a safe, minimally invasive test for study of major salivary glands. However, its relationship to salivary function has not been investigated in detail. We have investigated the relationship between major salivary gland flow rates and Tc-99 scans and developed a new rating scale using scans of a control group with normal salivary function. Salivary flow rates and Tc-99 scans were obtained from healthy, non-medicated subjects (n = 33) and from xerostomic patients (n = 22). There were significant differences between the groups for salivary flow rates and Tc-99 ratings. Significant correlations were found between salivary flow rates and Tc-99 ratings in the control and xerostomic groups. The Tc-99 rating scale proved reliable in assessing salivary dysfunction, and showed a high inter-examiner correlation. These results demonstrate the usefulness of salivary gland scintigraphy in assessing major salivary gland flow rates and the utility of a new rating scale.     

A survey of parental views regarding their child's hearing loss: a pilot study.

OBJECTIVE: Assess parental perceptions of their child's sensorineural hearing loss care. METHODS: Families of pediatric patients diagnosed with a sensorineural hearing loss from 2000 to 2004 were sent a survey asking about their experiences with their child's hearing loss. RESULTS: One hundred eight of 389 families surveyed were studied. Thirteen percent did not know the results of the newborn screening. Twenty-two percent of the primary care physicians were not involved in the child's hearing evaluation. Forty percent of the patients underwent 4 or more audiologic tests before a diagnosis. The most common reason for delayed diagnosis was difficulty in obtaining an appointment with an audiologist. Sixty-two percent of families had difficulties obtaining hearing aids, and 58% noted difficulties obtaining cochlear implants. CONCLUSIONS: Families reported multiple obstacles to obtain timely diagnosis and treatment. Otolaryngologists may need to be more involved in the evaluation and treatment of these patients. EBM rating: C-4.     

Papilledema in obstructive hydrocephalus caused by giant cell astrocytoma of tuberous sclerosis.

A 5-year-old girl with progressive hemiparesis and headache was found by brain imaging to have a large tumor centered at the foramen of Monro, blocking cerebrospinal outflow and producing massive lateral ventriculomegaly. Total excision of the mass led to a pathologic diagnosis of giant cell astrocytoma. Dermatologic abnormalities had been detected shortly after birth but were unexplained. Abdominal imaging disclosed renal cysts, and ophthalmologic examination disclosed papilledema and retinal plaques. On this basis, a diagnosis of tuberous sclerosis (TS) was finally made. Two months after surgery, papilledema had resolved, and visual function appeared to be normal. Although the patient apparently escaped visual loss, other reports affirm that giant cell astrocytoma, a common tumor in TS, may go undetected for long enough to produce irreversible optic neuropathy from chronic papilledema. Because patients with TS may not report visual loss, they should undergo periodic ophthalmologic screening.     

KCNJ2 mutations in arrhythmia patients referred for LQT testing: A mutation T305A with novel effect on rectification properties

BACKGROUND: Loss-of-function mutations in the KCNJ2 cause approximately 50% of Andersen-Tawil Syndrome (ATS) characterized by a classic triad of periodic paralysis, ventricular arrhythmia, and dysmorphic features. Do KCNJ2 mutations occur in patients lacking this triad and lacking a family history of ATS? OBJECTIVES: The purpose of this study was to identify and characterize mutations in the KCNJ2-encoded inward rectifier potassium channel Kir2.1 from patients referred for genetic arrhythmia testing. METHODS: Mutational analysis of KCNJ2 was performed for 541 unrelated patients. The mutations were made in wild type (WT) and expressed in COS-1 cells and voltage clamped for ion currents. RESULTS: Three novel missense mutations (R67Q, R85W, and T305A) and one known mutation (T75M) were identified in 4/249 (1.6%) patients genotype-negative for other known arrhythmia genes with overall incidence 4/541 (0.74%). They had prominent U-waves, marked ventricular ectopy, and polymorphic ventricular tachycardia but no facial/skeletal abnormalities. Periodic paralysis was present in only one case. Outward current was decreased to less than 5% of WT for all mutants expressed alone. Co-expression with WT (simulating heterozygosity) caused a marked dominant negative effect for T75M and R82W, no dominant negative effect for R67Q, and a novel selective enhancement of inward rectification for T305A. CONCLUSIONS: KCNJ2 loss of function mutations were found in approximately 1% of patients referred for genetic arrhythmia testing that lacked criteria for ATS. Characterization of three new mutations identified a novel dominant negative effect selectively reducing outward current for T305A. These results extend the range of clinical phenotype and molecular phenotype associated with KCNJ2 mutations.     

A Rose by Any Other Name? The Potential Consequences of Microglial Heterogeneity During CNS Health and Disease

Microglial activation and macrophage infiltration into the CNS are common features of CNS autoimmune disease and of chronic neurodegenerative diseases. Because these cells largely express an overlapping set of common macrophage markers, it has been difficult to separate their respective contributions to disease onset and progression. This problem is further confounded by the many types of macrophages that have been termed microglia. Several approaches, ranging from molecular profiling of isolated cells to the generation of irradiation chimeric rodent models, are now beginning to generate rudimentary definitions distinguishing the various types of microglia and macrophages found within the CNS and the potential roles that these cells may play in health and disease.     

The Rise of a New Psychoactive Agent: Salvia divinorum

Since the 1990s, there has been a rise in the availability and recreational use of a herbal plant called Salvia divinorum. Numerous internet websites have advertised it for sale as a legal herbal alternative to illegal hallucinogens. Initial data surveying use has indicated many young adults are obtaining and using this herb for its psychoactive properties. Reported methods of ingestion for the plant include chewing, and smoking leaves or fortified extracts. Subjective effects of the plant include, affect changes, psychedelic-like changes in perception, and even loss of consciousness. Although the pharmacological properties and possible antidepressant effects have been studied in recent years, little information is known about potential negative impact resulting from recreational use, and scant information about Salvia divinorum currently exists in the psychological and substance abuse literature. While Salvia divinorum appears to be a substance with some therapeutic potential, it also poses some significant dangers as a substance of varying legal status with a potential for abuse.