Prazosin treatment during the effector stage of disease suppresses experimental autoimmune encephalomyelitis in the Lewis rat

As part of a study on the role of vasoactive amines in experimental autoimmune encephalomyelitis (EAE), we have found that treatment beginning 7 days post-inoculation (dpi) with the specific alpha 1-adrenoceptor antagonist prazosin can significantly suppress clinical signs of disease in the Lewis rat. In this paper we have addressed the effect of treatment with prazosin commencing at varying times in the disease process. The results show that treatment during the early inductive stage (1 to 6 dpi) has no effect on the clinical course of the disease, whereas treatment commencing at the time of onset of early clinical signs (10 to 16 dpi) still significantly suppresses EAE. Leakage of serum proteins into the central nervous system (CNS) and histologic expression of EAE are also suppressed. Prazosin had no effect on lymphocyte responses to mitogen or antigen as determined by lymphocyte transformation tests when lymphocytes were exposed to prazosin in vitro, and the responses of lymphocytes from prazosin-treated animals were similar to those from saline-treated animals. These results support the hypothesis that prazosin suppresses EAE through a direct vascular effect although they do not preclude an immunologic component to its mechanism of action.     

EFFECT OF TREE CANOPY REMOVAL BY GYPSY MOTH LARVAE ON THE MACROALGAE OF A RHODE ISLAND HEADWATER STREAM1

A spring-fed, headwater stream in central Rhode Island was examined during the period from June to October, 1979 to 1982. In the first two summers, a dense riparian canopy reduced the light penetration at the stream surface to a range of 5 to 18% of incident radiation. The lotic macroalgal community during this period was limited to 1 to 4 species covering < 1 to 35% of the stream bottom. However, in June and July, 1981, the surrounding leaf canopy was removed by a massive gypsy moth larval outbreak. Light penetration to the stream during this summer increased to 73% by early July, thereby resulting in a rise in water temperatures by 3.7°C. Even though there was a partial regrowth of leaves in late July and August of 1981, macroalgal cover values continued to rise to an early August peak of 80%. During the third summer, 88% of the macroalgal abundance could be attributed to illumination and water temperature. The filamentous diatom Funotia pectinalis ( O.F. Müll.) Rabh. was the predominant species in the midsummer of all four years, accounting for at least 60% of the total cover. In 1981. an important taxon was the desmid Hyalotheca dissiliens (S. Smith) Bréb., a species which was not seen in other years. A less severe gypsy moth defoliation occurred in 1982 but did not produce significant differences in light, temperature or macroalgal cover from 1979 and 1980. The results indicate that light and temperature can be limiting during the summer in spring-fed, headwater streams and that seed populations of some species are present in undetect-able levels during these periods of suboptimal growth conditions. In addition, it appears that stream macroalgal communities can be quite resilient, recovering rapidly following a major perturbation .     

Regional and subcellular distribution of enzymes of branched-chain amino acid metabolism in brains of normal and diabetic rats

Branched-chain-amino-acid:alpha-ketoglutarate transaminase and branched-chain alpha-ketoacid dehydrogenase have been assayed in brains of control and of streptozotocin-induced diabetic rats. Enzyme activities were measured in five distinct regions of the brain: cerebellum, pons + medulla, midbrain, thalamus + hypothalamus, and telencephalon. Subcellular distribution of these enzymes in whole brain was assessed by fractionating brain homogenate into cytoplasm, free mitochondria, and synaptosomes. The following enzymes were used as markers: lactate dehydrogenase for cytoplasm, glutamate dehydrogenase for mitochondria, and glutamate decarboxylase for synaptosomes. The activity of the branched-chain amino acid transaminase in all brain regions was considerably higher than that of the branched-chain alpha-ketoacid dehydrogenase. While the highest activity of the transaminase occurred in brain-stem regions, the highest activity of the dehydrogenase was present in cerebellum and telencephalon. Diabetes did not affect the activity of the transaminase, but it caused a decrease in the total activity of the dehydrogenase in midbrain and in thalamus + hypothalamus. The transaminase was localized in the cytoplasmic fraction of whole brain, while the dehydrogenase was enriched in the free mitochondria.     

A preliminary study of aquatic insect communities and leaf decomposition in acid streams near Dorset,Ontario

Some streams near Dorset in south-central Ontario suffer from acid precipitation via run-off and seepage from thin soils with little buffering capacity. A spring-summer survey of eight headwater streams revealed some characteristics of their insect communities which could be correlated with pH. The streams could be divided into three groups according to pH and community structure. In the most acid group (annual pH range 4.3–4.8), Ephemeroptera were absent from two streams although mature Leptophlebia were collected just after spring thaw from the most acid one (pH 4.3–4.5). One of these three streams also lacked Plecoptera but the others had two or three genera, all shredders. The second group of three streams (pH 5.0–6.3), with one exception, did support Ephemeroptera (3–4 genera) and Plecoptera (1–4 genera), most of the latter being shredders. In all six of these acid streams, Trichoptera were more diverse and more dense than Ephemeroptera and Plecoptera; again, shredders were clearly dominant, especially the limnephilid caddisfly, Frenesia difficilis (Walker). These six streams also had similar chironomid communities (densities were an order of magnitude higher than other insects). Dominance by Chironomini and abundant Tanypodinae typified the most acid streams. In contrast, the two streams in the third group (pH 5.3–6.7) had richer and more balanced communities in general with relatively fewer shredders (no Frenesia), more collectors, and fewer Chironomini and Tanypodinae. As a field experiment showed that autumn-shed leaves decomposed more slowly in acid than in non-acid streams, summer-growing shredders may benefit from the pulse of acidity at snowmelt.     

Age-related changes of the somatotrophs of the domestic fowl Gallus gallus

Summary The ultrastructure of the somatotrophs of the caudal pituitary of the domestic fowl was studied quantitatively. Two age groups of male chickens were compared: 4–6 weeks and 24–30 weeks post-hatching. With age, somatotrophs decreased from about 40% to about 30% of the pituitary cell population. Their volume density decreased similarly. Mean volume of a somatotroph was the same in young and adult animals. Because the granule volume density of the somatotrophs was unchanged, but the somatotroph volume density of the gland declined, the granule volume density of the caudal pituitary gland dropped in parallel with that of the somatotrophs. Thus the volume of the gland comprised of somatotroph granules fell about 32%: from 6.57% to 4.45%. This lowered pool of stored hormone may be linked to the lowered circulating levels of growth hormone found in older animals by other investigators.The granule volume density of the somatotrophs was unchanged but the numerical density approximately doubled; thus the mean granule size decreased by 47% with age. The relationship of the size reduction of the granules to the lowered plasma growth hormone levels is not understood at present.Supported in part by Hatch and State funds from the New Jersey State Agricultural Experimental Station and NSF grants PCM 8,0227,27 and PCM 8,302197.     

Primary productivity of the River Ely,South Wales,U.K.

The present study was carried out on the non-tidal reaches of the River Ely, South Wales, from October 1979 to October 1980. The seasonal variations of the chlorophyll-a content of the phytoplankton was unimodal with one maximum in May and a minimum in December. The chlorophyll-a content varied from 0.277 to 41.259 mg m^?3. The primary productivity showed a bimodal seasonal distribution with two maxima in May and September and lower values throughout the remainder of the year, particularly in winter. The value for the primary productivity varied from 0.269 to 24.302 mg C m^?3 h^?1. A positive correlation was obtained between chlorophyll-a content and primary productivity. The seasonal distribution of the dominant algal species and the saprobity of the River Ely were also studied. The diatom species almost showed a similar seasonal periodicity. Their concentrations were low during the winter months and high during most of the spring and summer months. Many of the dominant diatom species found in the phytoplankton populations were either considered by the other authors as saprobic (Nitzchia palea) or as inhabitants of eutrophic waters (Gomphonema parvulum, Navicula cryptocephala and Synedra ulna). Chlamydomonas spp. were the most abundant green algae followed by Chlorella vulgaris. The effect of sewage effluent disposal and cattle excreta at three of the sampling sites might partly explain the presence of high Chlamydomonas spp. populations at those sites. Physical factors (low flow rates, high transparency and water temperature) and organic pollution at some sampling sites seemed to play an important role in increasing the number of algal species during spring and summer. The non-tidal reaches of the River Ely were found to be β-mesosaprobic above and below Station 5 and α-mesosaprobic at the latter station and therefore, the river can be considered as polluted at Station 5 and mildly polluted at the others.     

Algorithms for efficient planning and operation of a particular FMS

This article is a detailed case study of a particular FMS that will be operational in 1989. It describes the daily planning and operating problems that will need to be addressed. The algorithms that will operate this system are presented. Given the daily changing production requirements, the algorithms begin with an aggregate planning feasibility check. Then planning, scheduling, inventory management, and breakdowns are addressed. The key problems in operating this system are tool management problems. Detailed tooling data and their analysis are presented in an appendix to address these problems.     

Stereological analysis of mitochondria from brains of temperature acclimated goldfish, Carassius auratus L. (5 and 30°C)

1. 1.|The mitochondrial population in hypothalamic and hypophysial brain tissue from warm (30°C) and cold (5°C) acclimated goldfish (Carassius auralus L.) was analyzed using sterological techniques.

2. 2.|It was revealed that there is a significantly larger volume density (Vv) in the cold acclimated tissue, with no significant difference in either of the surface densities (Svext and Svint) from either of the brain areas.

3. 3.|The hypothalamic brain tissue has a significantly lower specific surface (S/V) in the cold acclimated tissue but there is not a significant difference in this parameter for the hypophysial brain tissue.

4. 4.|The values for these three parameters (Vv, Svext and SVint, and S/V) indicate that mitochondria from acclimated brain tissue undergo shape changes in response to thermal stress.

5. 5.|We suggest that the shape changes may be related to the change in the phospholipid composition of the inner mitochondrial membrane with acclimation temperature.

Serological response of non-human primates to human melanoma disialoganglioside GD3

Summary The immunogenicity of the disialoganglioside, GD3, a melanoma-tumor-associated antigen, has been evaluated in non-human primates. Sera from four chimpanzees and two monkeys were evaluated for anti-GD3 antibody activity by solid-phase radioimmunoassay using GD3 and control gangliosides as targets. Serum from one monkey, immunized with cells from a melanoma cell line, was strongly reactive with GD3, having a titer of >2500. In contrast, serum from this animal was non-reactive with several other gangliosides including the structurally similar GM3. Anti-GD3 reactivity was also demonstrable, albeit in low titer, in the sera of an additional monkey and a chimpanzee. Each of these animals had likewise been immunized using cells from melanoma cell lines. On the basis of these observations, suggestive of a primate anti-GD3 antibody response, we initiated a series of immunizations of chimpanzee using purified GD3 bound to Salmonella minnesota, R595. IgG reactive with melanoma cells in the cell-binding assay was first detected in sera collected after 4 immunizations and increased in titer against each reactive melanoma cell line during the immunizations. Reactivity of this serum with melanoma cell lines demonstrated a direct correlation with the expression of GD3 by the respective cell line. Anti-GD3 reactivity was evident in solid-phase radioimmunoassay against purified GD3 beginning with serum collected after 11 immunizations. By comparison with its binding to the control ganglioside panel, this serum demonstrated strong specificity for GD3 (titer=640) while having only marginal reactivity with GM3 (titer=40). Immune serum from this animal was also able specifically to block subsequent binding of a murine IgM anti-GD3 antibody (DMab7) to target GD3 in solid-phase radioimmunoassay. Together, these observations suggest that GD3, in the form of a purified molecule bound to a bacterial matrix or as part of the intact melanoma cell membrane, can be immunogenic in non-human primates, and is able to elicit an antibody response of appropriate specificity.Supported in part by grant CA32672 from the National Cancer Institute, Veterans Administration Program 821 and by the Yerkes Regional Primate Center, Atlanta, Georgia. The Yerkes Center is fully accredited by the American Association for Accreditation of Laboratory Animal Care