Evidence that the serotonin agonist, DOI, increases renin secretion and blood pressure through both central and peripheral 5-HT2 receptors

DOI [(+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCI] is a serotonin (5-HT1C/5-HT2) agonist, with potent cardiovascular effects. The purpose of the present studies was to determine the identity and location of the 5-HT receptor subtype(s) mediating the renin and blood pressure responses to DOI. Injection (i.p.) of DOI to conscious male rats elevated plasma renin activity in a dose-dependent manner. The 5-HT1C/5-HT2 antagonist ritanserin completely blocked the DOI-induced increase in plasma renin activity. In order to distinguish the 5-HT2- from the 5-HT1C- mediated effect of DOI, spiperone was administered before DOI. Low doses of spiperone (0.01 and 0.1 mg/kg, s.c.) significantly reduced the renin response to DOI. Because spiperone has a higher affinity for 5-HT2 than 5-HT1C receptors, these data suggest that DOI stimulates renin secretion through 5-HT2 receptors. To separate central from peripheral 5-HT receptors, we injected DOI into rats pretreated with saline or xylamidine, a 5-HT2 antagonist which does not cross the blood-brain barrier. Xylamidine produced a shift to the right and suppression of the maximal effect of DOI on plasma renin activity, suggesting a role for peripheral 5-HT2 receptors in the effect of DOI. On the other hand, i.c.v. administration of DOI, using doses lower than the peripherally effective doses, caused a significant elevation of plasma renin activity at 200 micrograms/kg. These experiments suggest that DOI's elevation of plasma renin activity has both peripheral and central sites of action.(ABSTRACT TRUNCATED AT 250 WORDS)     

Curriculum for musculoskeletal radiology.

Although general suggestions have been made regarding a radiology residency curriculum, no specific list of entities has been offered. Over the past ten years, we have developed a resident-run morning conference in musculoskeletal radiology that is supervised by faculty and covers a specific curriculum. We offer our curriculum as an example that may assist other departments in developing their own curricula.     

Family medical leave. An employee benefit for working caregivers of elderly family members

Future trends include a decrease in the number of adult children, an increase in the number of individuals over age 65, single parent families, working women, and individuals with no health care insurance. As more women with multiple roles and responsibilities enter and continue as part of the work force, employers recognize the need for support of family issues. Currently many employers lack initiative to make these needed changes. The occupational health nurses' role in relation to future policy for working caregivers includes assessment of how employment and caregiving impact work performance, job satisfaction, and health; and participation in defining public policy issues.     

Does chronic prenatal methadone exposure affect beta-receptor subtypes in placental, fetal and maternal brain homogenates?

Computer competition analysis of 3H-DHA (3H-dihydroalprenolol, a nonselective beta-adrenergic radioligand) binding in the presence of unlabeled metoprolol (a beta 1-selective antagonist) indicates the existence of both beta 1- and beta 2-adrenergic receptor subtypes in the rat placenta and confirms previous reports that both beta-adrenoceptors are present in adult rat cortex. In the fetal brain (20th day of gestation), however, only beta 1-receptors were detected. Pregnant rats were chronically exposed to methadone from day 7 to day 20 of gestation via implanted osmotic minipumps (6.3-9.0 mg/kg/day). This treatment schedule did not induce a change in the affinity and density of either beta-receptor subtype in the placental, fetal and maternal brain homogenates. The results are discussed in terms of the reported monoaminergic and opiate receptor functional interactions.     

The edematous hand

The purpose of this article is to increase the therapist's awareness of the effects of edema on the hand and the need for early treatment. The physiology of tissue fluid production and the two basic types of edema are discussed. The use of elevation, compression, and active exercise are the primary methods of controlling edema in the hand. Various modalities and commercial compression dressings are helpful for intractable edema; however, early intervention and treatment of the edematous hand can prevent subsequent hand dysfunction and sequelae.     

Prolonged running does not improve muscle coordination after cross-union of tibial and peroneal nerves in mice

Several months after cross-union of the tibial and peroneal nerves and full muscle reinnervation motor behavior was monitored and was tested by electromyographic recordings from both musculus tibialis anterior (TA) and musculus gastrocnemius medialis (MG). In addition spinal motoneuron pools were labelled by injecting wheat-germ agglutinin-horseradish peroxidase (WGA-HRP) into experimental and control TA muscles. Though the location of TA motoneurons was similar in all 9 mice tested and suggested successful cross-reinnervation, running behavior and EMG patterns varied remarkably. In some animals the alternating activities of TA and MG muscles remained more or less clearly separated from each other but were out of phase with the running cycle. A somewhat better motor behavior was accompanied by simultaneous activity in both muscles. Voluntary running in wheels for several kilometers per day did not visibly improve motor coordination indicating the absence of activity-related synaptic readjustments.     

Craniopharyngioma of the cranial base and nasopharynx

A rare case of craniopharyngioma extending to the cranial base and nasopharynx is reported and eight other cases in the literature are reviewed. The embryology and the clinical features of these tumors are discussed. Tomograms of the skull and computed tomography are the most useful radiological tools of investigation. A nasoseptal or transpalatal approach to surgery, which has been performed in reported cases of cystic nasopharyngeal craniopharyngiomas, was not performed on our patient because of the hard consistency and the diffusely infiltrating aspect of the tumor.     

Lesser metatarsophalangeal joint implants

A double-stemmed MTP joint silastic implant has been described that acts as a flexible spacer for a number of pathologic conditions that affect the lesser metatarsophalangeal joints. Preliminary results suggest that this is a feasible alternative to joint destructive procedures with advantages over previously described implants.