Innervation of the zona fasciculata of the adult human adrenal cortex: a light and electron microscopic study

Summary Autonomic innervation of the adrenal cortex has been demonstrated in several species. Detailed ultrastructural studies on the innervation of the zona fasciculata of the normal human adrenal cortex are lacking. We report herein our observations on the pattern of innervation of the cells of the zona fasciculata of the normal adult human cortex at both the light and electron microscope levels. Postganglionic unmyelinated fibers were observed to descend from a dense capsular meshwork and to be distributed as delicate branches among the columns of endocrine cells. Immunoperoxidase staining confirmed the presence of nerve fibers in the zona fasciculata in a distribution similar to that observed after staining with silver impregnation methods. Ultrastructural findings lent further support to these observations by the demonstration of bundles of unmyelinated fibers with focal enlargements containing terminal boutons with both clear and dense core vesicles in close approximation with the endocrine cells.     

Effects of depleting central and peripheral adrenaline stores on blood pressure in stroke-prone spontaneously hypertensive rats

The potential role of adrenaline, both circulating and in the central nervous system, in the maintenance of high blood pressure was examined in stroke-prone spontaneously hypertensive rats (SHRSP). alpha-Monofluoromethyldopa, a long-lasting inhibitor of dopa decarboxylase, was used to induce rapid depletion of central and peripheral catecholamine stores. Subsequent inhibition of phenylethanolamine-N-methyltransferase (PNMT) allowed the gradual restoration of dopamine and noradrenaline but not adrenaline, resulting in a greater relative depletion of adrenaline. Adrenaline was almost totally depleted in the circulation and peripheral tissues. The resting level of blood pressure, however, was unaffected, excepting after administration of a vasopressin (AVP) antagonist. Moreover, there was no reduction in the magnitude of acute pressor responses to electrical stimulation of the rostral ventrolateral medulla oblongata (C1 area), despite extensive loss of adrenaline from the brainstem and spinal cord. The results suggest that adrenaline contributes to the resting level of blood pressure but that its loss can be offset by the pressor activity of AVP. Thus neither central nor peripheral adrenaline stores appear to be essential for the maintenance of hypertension or for centrally-evoked vasoconstriction in adult SHRSP.     

Studies on the contact system of coagulation during therapy with high doses of recombinant IL-2: implications for septic shock

Patients treated with high doses of interleukin-2 (IL-2) because of cancer, develop hemodynamic and vasopermeability changes, that resemble those observed in sepsis. These patients thus provide a unique opportunity to study the early events in the development of septic shock. We analysed the changes that occurred in the contact system of coagulation in plasma from 4 patients, who together received seven 12-day cycles of high doses of IL-2. Levels of factor XII and prekallikrein during the cycles progressively fell to 50 and 30% of their initial levels, respectively, whereas significant increases in plasma factor XIIa- and kallikrein-C1-inhibitor complexes were not observed (in 3 out of 211 samples slightly increased levels of both complexes were found). The reductions in factor XII and prekallikrein were only in part due to protein leakage, since levels were still significantly lower, i.e., 80 and 50%, respectively, when corrected for albumin decreases. Levels of high molecular weight kininogen (HMWK) also decreased during IL-2 therapy, however, this decrease paralleled that of albumin. SDS-PAGE analysis of plasma HMWK did not reveal increased cleavage of this protein. The reduction of factor XII and prekallikrein, corrected for protein leakage, significantly correlated with albumin levels and inversely with daily cumulative weight gain in the patients. Thus, we demonstrate that factor XII and prekallikrein decrease during IL-2 therapy. As these decreases, already observed after 1 day treatment, were disproportional to that of albumin, a negative acute phase reactant, and correlated with signs of the vascular leak syndrome, we favor the explanation that they reflected activation rather than a decreased synthesis of the contact system proteins.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of 2,3,5-triphenyltetrazolium chloride staining to delineate rat brain infarcts.

BACKGROUND AND PURPOSE: Accurate and reproducible determination of the size and location of cerebral infarcts is critical for the evaluation of experimental focal cerebral ischemia. The purpose of this study was to compare intracardiac perfusion of 2,3,5-triphenyltetrazolium chloride with immersion of brain tissue in 2,3,5-triphenyltetrazolium chloride to delineate brain infarcts in rats. METHODS: After 6, 24, or 48 hours of ischemia induced by permanent middle cerebral artery occlusion, some rats were perfused with 2,3,5-triphenyltetrazolium chloride; other rats were given an overdose of barbiturates, after which brain sections were immersed in 2,3,5-triphenyltetrazolium chloride. Coronal sections were taken 4, 6, and 8 mm from the frontal pole, and infarct areas in perfused and immersed sections were compared; subsequently, the same sections were stained with hematoxylin and eosin. RESULTS: In rats subjected to 24 or 48 hours of occlusion, areas of infarction were clearly defined with both 2,3,5-triphenyltetrazolium chloride staining techniques, and the infarct sizes correlated well with the results of hematoxylin and eosin staining (r = 0.85-0.94). CONCLUSIONS: These results demonstrate that intracardiac perfusion of 2,3,5-triphenyltetrazolium chloride is an accurate, inexpensive, and efficient staining method to detect infarcted tissue 24 and 48 hours after the onset of ischemia in rats.     

Cerebral hemorrhagic risk of aspirin or heparin therapy with thrombolytic treatment in rabbits

We studied the incidence of cerebral hemorrhage in an animal model of embolic stroke to determine the safety of aspirin, heparin, and tissue plasminogen activator therapies. We occluded the middle cerebral arteries of rabbits with labeled blood clots and administered either tissue plasminogen activator, heparin, aspirin, tissue plasminogen activator plus aspirin, tissue plasminogen activator plus heparin, or saline at various times after stroke. Compared to saline controls, both the aspirin-only and the tissue plasminogen activator-plus-aspirin groups had a significantly higher incidence of cerebral hemorrhage, whereas the heparin and tissue plasminogen activator combination groups did not. We conclude that aspirin antiplatelet therapy alone may increase the risk of hemorrhagic infarction, whereas heparin or tissue plasminogen activator therapy appears to be relatively safe.     

Experience with a metered-dose inhaler with a spacer in the pediatric emergency department

Studies of adults suggest that metered-dose inhalers with spacers are as effective as hand-held nebulizers for bronchodilator delivery. We studied 13 children with acute asthma. They received two puffs every 2 minutes from metered-dose inhalers with spacers (range, 4 to 14 puffs) titrated until improvement stopped. Peak expiratory flow increased 34% for metered-dose inhalers with spacers after the first 2 puffs and increased 87% for metered-dose inhalers with spacers after dose titration. After titration, respiratory rate decreased by 12%, heart rate increased by 2%, and breath sounds improved in 92% of the patients. We concluded that the metered-dose inhalers with spacers are an effective device for the treatment of asthma in the pediatric emergency department and that the use of metered-dose inhalers with spacers with titration can achieve significant bronchodilation in the treatment of patients with acute asthma.     

Ultrastructural features of NPY-containing neurons in the rat striatum

In the present study, we examined the ultrastructure of striatal neurons containing neuropeptide Y (NPY) which were labeled by an immunohistochemical method using peroxidase-conjugated F(ab) fragments in the rat. Each of the 26 neurons identified had a deeply indented oval nucleus. The cytoplasm, which was mainly concentrated at the emergence of the dendrites, contained an abundant Golgi apparatus and a well-developed granular endoplasmic reticulum. Dendrites were poorly branched and rarely exhibited varicosities or dendritic spines. NPY-immunoreactive (Ir) axons were small in diameter and unmyelinated. These features corresponded to a subpopulation of striatal neurons classified as aspiny type IV in previous Golgi studies. Axon terminals forming symmetrical synapses were numerous on the NPY-Ir perikarya and proximal dendrites. On distal NPY-Ir dendrites, synaptic contacts were mainly of the asymmetrical type, suggesting that NPY neurons are contacted by at least 2 categories of afferent fibers. Several NPY-Ir axonal processes and boutons were found to form symmetrical synapses with dendrites, dendritic spines and perikarya belonging to spiny type neurons. These data were consistent with the view that NPY may act as a neurotransmitter of striatal interneurons. Moreover, the frequent observation of NPY axonal processes in the close vicinity of striatal vessels suggested that NPY might also play a role in the control of cerebral vasomotricity. Thirty hours after intranigral injection of 6-hydroxydopamine to induce a degeneration of nigrostriatal dopamine terminals, some characteristic degenerative boutons were observed in close apposition to NPY-Ir cell bodies, suggesting that NPY neurons are under a direct nigrostriatal dopaminergic influence.     

Evaluation of the rat tail model for estimating dermal absorption of lindane

Dermal absorption of the insecticide lindane was determined following topical application of ring 14C-labeled lindane to the tail of Sprague-Dawley rats. The tail was tested as a practical alternative to the rat mid-dorsal (back) region, and the data obtained were compared to those with rat back and with those of rhesus monkeys in our previous reports. There was no significant difference between total percentage urinary 14C recovery for rats dosed on the tail with occlusive tail covers (52 +/- 6.2%; t1/2 = 2.7 d) compared to those with nonocclusive covers (55 +/- 4.4%; t1/2 = 2.9 d). Neither the total percentage urinary recovery nor the t1/2 values obtained for the rat tail and rat back models differed significantly. Carbon-14 activity was still detectable in urine samples taken after 72 d post-treatment. However, an extensive tissue analysis failed to demonstrate 14C activity persisting at 72 d, with the exception of trace levels detected in blood serum and tail tissue. Advantages of the rat tail model are highlighted.     

PharmaTrend as a management tool: capturing workload data

Several methods of collecting workload data for use in PharmaTrend, a computerized pharmacy management information system, are described. Although the number of indicators produced by PharmaTrend is limited by the input of the user, the integrity of the indicators that are produced is not compromised; this allows the user to implement PharmaTrend on a limited scale, such as for workload only. Workload data that can be used in PharmaTrend are collected routinely by most pharmacies. Many activities are already recorded in logs and other noncomputerized sources. The aid of members of the pharmacy department and other departments may be enlisted in collecting these data. Self-reporting through time sheets and cards can also be used to obtain data on the distribution of work hours. Recording is simplified if employees are told to record only exceptions to their usual job responsibilities. The PharmaTrend manual contains detailed definitions of the workload categories, but simpler and more practical definitions may have to be used. A computer spreadsheet program should probably be used for compiling data if they are collected from several sources; this will facilitate entry into PharmaTrend. Simple methods are available for capturing workload data for input into the PharmaTrend program.