M. M. Magalhães

The substantia gelatinosa Rolandi of the rat. Fine structure, cytochemistry (acid phosphatase) and changes after dorsal root section

SummaryThe rat substantia gelatinosa Rolandi (lamina II) was found to contain synaptic glomeruli at the centre of which was a dark terminal (C-terminal) full of round synaptic vesicles. The C-terminal was presynaptic to several dendritic profiles and to terminals containing sparse pleomorphic synaptic vesicles, and was occasionally postsynaptic at symmetrical contacts to other terminals containing numerous pleomorphic vesicles of which about one-third were elongated. Acid phosphatase activity was observed on, and between, the membranes of the synaptic vesicles of the central bouton, as well as in the hyaloplasm of the peripheral elements of the glomeruli. Dorsal root section caused electrondense degeneration of the central boutons. Acid phosphatase activity disappeared from synaptic vesicle membranes in C-boutons, and gradually filled their dense cytoplasmic matrix. The enzyme disappeared completely from the peripheral profiles.The synaptic glomeruli of the rat gelatinosa are thus a synaptic relay station for primary afferents, whose terminals possess an extralysosomal acid phosphatase possibly concerned with the metabolism of a local synaptic transmitter. Enzyme accumulation in degenerating knobs seems to be an autolytic process distinct from the normal function of this acid phosphatase.

Pulmonary Function Electronic Monitoring Devices: A Randomized Agreement Study

STUDY OBJECTIVES To compare in a clinical setting the within-session reproducibility of two pulmonary function electronic monitoring devices (PiKo-1; Ferraris Respiratory Europe; Hereford, UK; and Spirotel; MIR; Rome, Italy) with one mechanical device (Mini-Wright Peak-Flow Meter; Clement-Clarke International; Harlow, Essex, UK), and to evaluate the accuracy of these devices using as reference an office pneumotachograph. DESIGN, SETTING, AND PARTICIPANTS After detailed instructions, adults without airways diseases and patients with stable asthma attending an outpatient clinic performed four sets of expiratory maneuvers, one set for each device, in a strictly random order. Each set comprised three maneuvers with 2 to 3 min of rest between them. MEASUREMENTS Reproducibility of FEV1 and peak expiratory flow (PEF) was assessed by a coefficient of variation (CV) and intraclass correlation coefficient (ICC), and accuracy was assessed by ICC and limits of agreement. RESULTS Of the 38 participants evaluated, 71% were women and 61% had asthma. Ages ranged from 18 to 58 years, and FEV1 ranged from 1.2 to 4.8 L. In all monitoring devices, CV was < 6% and ICC was > 0.94 for the reproducibility of both FEV1 and PEF measurements. The accuracy of the PiKo-1 device was better for FEV1 (ICC = 0.98) than for PEF (ICC = 0.90). The Spirotel device had similar results for FEV1 and PEF (ICC = 0.95). The Mini-Wright device had the lowest accuracy (ICC = 0.87), particularly for PEF values < 500 L/min. CONCLUSIONS These low-cost and easy-to-use electronic monitoring devices showed a very good reproducibility and were in agreement with the pneumotachograph. Therefore, the PiKo-1 and Spirotel devices seem adequate for both screening and monitoring. However, prospective studies are still needed to assess their long-term reproducibility and usability and, particularly, the effects on the improvement of respiratory care.

The rabbit retina Müller cell. A fine structural and cytochemical study

The rabbit retina Muller cell is formed by three portions. In the dilated inner portion, the cytoplasm has abundant microfilaments, a network of glucose-6-phosphatase-positive smooth-walled vesicles, numerous glycogen β -particles, and some acid phosphatase-positive dense bodies. The nucleated middle portion has fewer microfilaments and glycogen particles, a number of ergastoplasmic cisternae, and an acid phosphatase-positive Golgi complex. The outer portion has light cytoplasm with microtubules and no microfilaments, scarce glycogen particles, and mitochondria. The cell plasma membrane is thinner than that of retinal neurons; around both, intercellular spaces are filled by ruthenium-red reactive material. The Muller cell cytoplasm is pyroantimonate-reactive and rich in digitonin—cholesterol complexes. This and the abundance of microfilaments and glycogen in the two innermost portions suggest a basic astrocyte type of cell modified in the outer portion for absorption and transport of nutrients. Glucose is probably taken up here and stored in the inner portion to be used in anaerobic glycolysis. Secretion of exportable protein appears to occur in the middle portion.

Microbodies (Peroxisomes) in rat adrenal cortex

Electron microscope examination of the rat adrenal cortex revealed the presence of round or ovoid small bodies measuring 0.10–0.76 μ in diameter, limited by a single unit membrane (∼ 69 A thick), in the cytoplasm of cells of all zones, particularly the zona fasciculata. These bodies contained a finely granular matrix of moderate density and were occasionally connected with the endoplasmic reticulum. When glutaraldehyde-fixed, 30-μ thick sections were incubated in DAB-containing medium prepared according to Beard and Novikoff (5) and post-fixed with osmium tetroxide; dense deposits of reaction product appeared in the matrix of those bodies. Reaction product was absent from the bodies in sections incubated in medium without DAB, and was decreased or absent after incubation in medium without H2O2. Addition of catalase completely inhibited the slight staining observed in bodies incubated in medium without H2O2. High concentrations of H2O2, aminotriazole or KCN in the incubation medium rendered the reaction negative. It is concluded that such bodies contained catalase and may therefore be considered as true peroxisomes.

Clinical InvestigationsPulmonary Function Electronic Monitoring Devices: A Randomized Agreement Study

STUDY OBJECTIVES To compare in a clinical setting the within-session reproducibility of two pulmonary function electronic monitoring devices (PiKo-1; Ferraris Respiratory Europe; Hereford, UK; and Spirotel; MIR; Rome, Italy) with one mechanical device (Mini-Wright Peak-Flow Meter; Clement-Clarke International; Harlow, Essex, UK), and to evaluate the accuracy of these devices using as reference an office pneumotachograph. DESIGN, SETTING, AND PARTICIPANTS After detailed instructions, adults without airways diseases and patients with stable asthma attending an outpatient clinic performed four sets of expiratory maneuvers, one set for each device, in a strictly random order. Each set comprised three maneuvers with 2 to 3 min of rest between them. MEASUREMENTS Reproducibility of FEV1 and peak expiratory flow (PEF) was assessed by a coefficient of variation (CV) and intraclass correlation coefficient (ICC), and accuracy was assessed by ICC and limits of agreement. RESULTS Of the 38 participants evaluated, 71% were women and 61% had asthma. Ages ranged from 18 to 58 years, and FEV1 ranged from 1.2 to 4.8 L. In all monitoring devices, CV was < 6% and ICC was > 0.94 for the reproducibility of both FEV1 and PEF measurements. The accuracy of the PiKo-1 device was better for FEV1 (ICC = 0.98) than for PEF (ICC = 0.90). The Spirotel device had similar results for FEV1 and PEF (ICC = 0.95). The Mini-Wright device had the lowest accuracy (ICC = 0.87), particularly for PEF values < 500 L/min. CONCLUSIONS These low-cost and easy-to-use electronic monitoring devices showed a very good reproducibility and were in agreement with the pneumotachograph. Therefore, the PiKo-1 and Spirotel devices seem adequate for both screening and monitoring. However, prospective studies are still needed to assess their long-term reproducibility and usability and, particularly, the effects on the improvement of respiratory care.

Age-related changes in the inner zone of the adrenal cortex of the rat—a morphologic and biochemical study

In this work, a correlative morphologic and biochemical study on the effects of ageing on the rat adrenal Inner Zone (IZ) was made. Male Wistar rats were studied at 2, 6, 12, 18 and 24 months. Structural data of Zona Fasciculata (ZF) showed age-related increase in cell volume (P < 0.05), decrease in mitochondria (P < 0.01) and smooth endoplasmic reticulum (SER) volumes, and increase in lipid droplets (P < 0.01) and lipofuscin granules (P < 0.01) volumes. In Zona Reticularis, the main change observed was the increase in lipofuscin granules (P < 0.001). Serum corticosterone from unstimulated rats increased until 12 months but decreased thereafter (P < 0.01), to levels below those from 2-month-old rats. Similarly, plasma adrenocorticotrophic hormone (ACTH) presented a maximum at 12 months, followed by a decrease to levels higher than at 2 months (P < 0.05). In rats injected either with only ACTH or dexamethasone, before ACTH stimulation, corticosterone level had a maximum at 12 months. In aged rats, serum high density lipoprotein (HDL) and adrenal cholesterol ester increased significantly (P < 0.05 and P < 0.01, respectively), whereas adrenal corticosterone decreased. Products of lipid peroxidation, assayed with the thiobarbituric acid reaction and fluorimetry showed an age-related increase (P < 0.05). The age-related decrease in mitochondria and SER volumes is consistent with the decrease of serum corticosterone. The increase in lipid droplet and HDL and the reduction of adrenal corticosterone level correlate with the increase of adrenal cholesterol ester content. These suggest a continued uptake of steroid precursor but a reduced steroid synthesis. On the whole, the data provide evidence for an age-related reduced functional ability of IZ and particularly of ZF.

Peroxisomes in adrenal steroidogenesis

Peroxisomes, cytoplasmic organelles limited by a single membrane and with a matrix of moderate electron density, are present in a great number of cells, namely in adrenal cortex and other steroid‐secreting organs. Presently peroxisomes are considered to be involved in important metabolic processes. They intervene in: (1) the production and degradation of H2O2; (2) biosynthesis of ether‐phospholipids, cholesterol, dolichol, and bile acids; (3) oxidation of very long chain fatty acids, purines, polyamines, and prostaglandins; (4) catabolism of pipecolic, phythanic and glyoxylic acids; and (5) gluconeogenesis. Recent studies demonstrated that the experimental alterations in the normal steroidogenesis, produce significant morphological and biochemical changes in peroxisomes. Besides this, the presence of 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase (the key enzyme in the de novo cholesterol synthesis from acetate) and of sterol carrier protein‐2 (SCP2), which is involved in the cholesterol metabolism and steroid metabolic pathways, are located in peroxisomes of steroid‐secreting cells. In addition, patients with peroxisome diseases present deficiency in steroidogenesis, as well as reduced levels of SCP2. These data pointed out the important role of peroxisomes in steroid biosynthesis. Microsc. Res. Tech. 36:493–502, 1997.

Effects of ovariectomy and estradiol administration on the adrenal macrophage system of the rat.

SummaryMacrophages of the adrenal cortex were studied in normal male and female, ovariectomized and estradiol-injected rats. In normal male rats few macrophages with numerous granules were observed in the zona fasciculatazona reticularis border, and in the zona reticularis. Granules, identified as lysosomes, were limited by a single membrane with a heterogeneous matrix; they exhibited acid phosphatase- and aminotriazole-resistant peroxidatic activities. A larger number of macrophages had identical distributions in normal female rats. In ovariectomized and estradiol-injected rats the number and distribution of adrenal macrophages were similar to those in normal females; however, in spayed animals the number of these cells in the zona reticularis was higher than in the other experimental groups. Lysosomes in macrophages of treated animals were more numerous and their contents more complex than in normal male animals. These results indicate that the adrenal macrophage system is stimulated in experimental conditions involving high levels of circulating estrogens.

Age-related changes in lipid peroxidation products in rat adrenal gland

Chloroform-methanol extracts from rat adrenals at five different ages (2, 6, 12, 18 and 24 months), were studied by fluorescence. After obtaining excitation and emission spectra, fluorescence intensity was measured at 365 nm excitation and 455 emission for all time points of aging. An additional study of lipid peroxidation employing a thiobarbituric acid reaction was made.Fluorescence intensity increased during aging from 16.39 × 103 arbitrary units of fluorescence per gram of tissue at 2 months, to 34.33 × 103 units at 24 months. Thiobarbituric acid reaction products expressed in nmol of malondialdehyde per gram of adrenal increased from 172.97 at 2 months to 640.83 at 24 months. One way analysis of variance revealed a statistically significant difference (p<0.05 and p<0.01 respectively).The results show an age-related steady increase in lipid peroxidation products in rat adrenals and suggest their accumulation in lipofuscin granules.

Postnatal development of the rat adrenal cortex: an ultrastructural morphometric study

Adrenals from 12-hr, 4 1/2, 7 1/2, 10-, and 14-day-old rats were used in this study. At 12 hr the cells of the zonae glomerulosa and fasciculata were similar to those of the adult adrenal cortex. The zona juxtamedullaris cells presented round mitochondria with vesicular cristae and very dense matrix and a large endoplasmic reticulum. After this age and until the 14th day, changes were slight and mainly regarding the size of cytoplasmic organelles. Variations in volumetric and surface densities were determined by stereological methods. These showed between 12 hr and 4 1/2 days of life in the three cortex zones a significant decrease of the volumetric densities of mitochondria (except the zona juxtamedullaris) and the endoplasmic reticulum (except in the zona glomerulosa) and a significant increase in the relative volume of the lipid droplets. The surface density of mitochondria decreased in the three zones, and the same parameter for the lipid droplets significantly increased in the zonae glomerulosa and fasciculata. After 4 1/2 days there was, in the three zones, an increase in the volumetric density of the mitochondria and endoplasmic reticulum and an increase in the mitochondrial surface density which were significant in most cases; the volumetric and surface densities of the lipid droplets increased except in the zona juxtamedullaris. These data suggest a decrease in the adrenal metabolic activity during the first days of life, which increases thereafter until reaching normal values.