Portal circulations and their relation to counter-current systems.

We have reviewed the distribution of portal circulations throughout the animal body; they are commoner than is generally supposed. Most portal circulations consist of two serial capillary beds connected by one or more larger vessels. We have called these 'convergent' portal circulations: examples are hepatic portal, placental, hypophysial, renal, ovarian and testicular circulations, as are parts of the lymphatic circulation. A second type of portal circulation, which is less common, consists of two serial capillary beds that are not connected by larger vessels. These we have called 'continuous' portal circulations: adrenal and pancreatic circulations are examples of this type. When a countercurrent concentrating mechanism exists in the body it is always part of the primary or secondary bed of a convergent portal circulation, though some convergent portal circulations are not associated with countercurrent mechanisms.     

Hypothalamic self-stimulation and stimulation escape in relation to feeding and mating.

This review begins with James Olds' discovery that self-stimulation at various brain sites can be influenced by food intake or androgen treatment. It then describes our research designed to reveal the functional significance of self-stimulation. The evidence suggests that lateral hypothalamic self-stimulation is controlled by many of the same factors that control feeding. We believe this control is exerted by at least two neural mechanisms. One is the classical, medial hypothalamic satiety system. Another is an adrenergic system ascending from the midbrain to the lateral hypothalamus. Damage to either one can disinhibit self-stimulation and feeding, thus contributing to obesity. Some of our studies use rats with two electrodes, one that induces feeding and one that induces mating. There are two response levers in the test cage, one for self-stimulation and one for escape from automatic stimulation. With the feeding electrode, rats self-stimulated less and escaped more after a meal than before. The same shift occurred after an anorectic dose of insulin or the commercial appetite suppressant phenylpropanolamine. With the sex electrode the shift from reward to aversion occurred after ejaculation. The review ends with credit to James Olds for pioneering this line of research into the neuropsychology of reinforcement.     

Evidence for antipyretic vasopressinergic pathways and their modulation by noradrenergic afferents.

The experimental evidence for the antipyretic action of arginine vasopressin (AVP) in guinea-pigs can be summarized as follows: The febrile response to a bacterial pyrogen can be reduced by a microinfusions of exogenous AVP into the ventral septal area of the limbic system. Immunohistochemical studies indicate increased activity of AVP terminals in the ventral septal area (VSA) and in parvocellular AVP neurones of the hypothalamic paraventricular nucleus (PVN) in several stressful situations accompanied by reduced febrile responses (late stage of pregnancy, immobilization, cold adaptation, osmotic stimulation). Also the peripheral and/or central release of AVP measured in some of these situations is increased. Electrical stimulation of the PVN suppresses fever, this suppression can, at least partly, be cancelled by simultaneous intraseptal application of the vasopressinergic V1 receptor antagonist. The documented AVP pathways from the PVN to the septum receive noradrenergic afferents from the lower brainstem. Chronic destruction of these afferents by microinjections of 6-hydroxydopamine (6-OHDA) significantly reduced the fever responses to pyrogen application, while microinfusion of noradrenaline (NA) enhances the fever reaction.     

A central link between angiotensinergic and cholinergic systems; role of vasopressin

Participation of central cholinergic system in the effects of intracerebroventricular (i.c.v.) injection of angiotensin II (Ang II) on blood pressure and heart rate was studied in conscious, freely moving rats. Ang II dose-dependently increased blood pressure and decreased heart rate. Both atropine and mecamylamine (i.c.v.) pretreatments prevented the cardiovascular effects of Ang II. Pretreatment with a vasopressin V1 antagonist also prevented the cardiovascular responses to Ang II. Our data suggest that the central pressor effect of Ang II is mediated in part by central acetylcholine via both muscarinic and nicotinic receptors, and vasopressin participates in this effect through V1 receptors.     

Reactions of oxytocin- and vasopressinergic cells of the hypothalamic supraoptic and paraventricular nuclei in the rat to repeated administrations of thyroliberin

Male Wistar rats were injected with 1 microgram thyroliberin twice a day for 8 days. Vasopressinergic (VE) and oxytocinergic (OE) cells of the supraoptic (SON) and paraventricular nuclei (PVN) were detected immunohistochemically, their changes were estimated morphometrically. The blood level of the thyrostimulating hormone determined by radioimmunoassay was 220% of the control on the 6th day but declined by the 9th day. The thyroid hormone concentration was also diminished. The nucleoli of the VE and OE cells of the SON were reduced by the 9th day (by 74 and 82%, respectively; P less than 0.01). The nucleoli of the OE cells of the PVN were enlarged to 120% (P less than 0.01), hence production of the neurohormone by these cells was intensified. The VE cells of the PVN remained essentially unchanged. The data obtained suggest that disagreement between the PVN and SON cell reactions is caused by various reactions of the nerve centers conveying toward the PVN and SON. Moreover, the OE and VE cells of the PVN apparently differ in their input. The importance of the OE cells of the PVN for the thyrostimulating hormone level normalization is suggested.     

The alpha-chain-termination mutants and their relation to the alpha-thalassaemias.

The structure, synthesis, genetic transmission, clinical associations and distribution of the elongated alpha-chain haemoglobin variants has been described. The data indicate that the most likely molecular basis for these common abnormal haemoglobins is a single base substitution in the alpha-chain termination codon. Because these variants are produced inefficiently they give rise to the clinical picture of alpha-thalassaemia. When these findings are taken together with recent work regarding the molecular basis for other forms of alpha-thalassaemia it is possible to build up a fairly complete picture of the molecular pathology of the alpha-thalassaemias.     

Ultrastructural features of presumptive vasopressinergic synapses in the hypothalamic magnocellular secretory nuclei of the rat

Despite convincing physiological evidences for vasopressin (VP) autoregulation in the supraoptic (SON) and paraventricular (PVN) nuclei, the morphological demonstration of VP synapses has lagged behind. The present work investigates the possible existence of such synapses in the SON and PVN of the rat. Electron microscopy of sections immunostained with VP antibody (1:5,000) and conjugated with avidin-biotin demonstrated presynaptic terminals containing neurosecretory granule (NSG)-like bodies, 80-100 nm in diameter. The terminals formed axodendritic, axosomatic and axoaxonic synapses, though the postsynaptic elements remained largely unidentified. Other ultrastructural features of synaptic specialization were evident. The NSG-like bodies exhibited a varying and dynamic relationship to the presynaptic membrane, suggesting their involvement in synaptic mechanisms.     

Morphometry of nuclei of the normal and malignant prostate in relation to DNA ploidy.

Fine needle biopsies from 70 patients with prostate carcinoma and 10 patients with benign hyperplasia were used to study area, variation in size and form factors of the nuclei by image analysis. The results were related to DNA ploidy of the cell populations as measured by flow cytometry, cytologic grade and patients' survival. Nuclear area differed significantly between benign lesions and tumors. It increased in diploid low-grade tumors from a normal value of 54.2 +/- 3.1 microns2 to 75.6 +/- 5.3 microns2. In aneuploid tumors with an increase in the chromosome number, the nuclear size further increased to about twice that of benign nuclei. Variation in size also differed between benign and malignant epithelium, with a further increase between diploid and gross aneuploid tumors. While nuclear size and variation in nuclear size made it possible to discriminate malignant from benign lesions, form factor did not differ between benign and malignant lesions. In follow-up, however, none of these factors reached significance for predicting survival.     

Zipf's law leads to Heaps' law: analyzing their relation in finite-size systems

Background

Zipf''s law and Heaps'' law are observed in disparate complex systems. Of particular interests, these two laws often appear together. Many theoretical models and analyses are performed to understand their co-occurrence in real systems, but it still lacks a clear picture about their relation.

Methodology/Principal Findings

We show that the Heaps'' law can be considered as a derivative phenomenon if the system obeys the Zipf''s law. Furthermore, we refine the known approximate solution of the Heaps'' exponent provided the Zipf''s exponent. We show that the approximate solution is indeed an asymptotic solution for infinite systems, while in the finite-size system the Heaps'' exponent is sensitive to the system size. Extensive empirical analysis on tens of disparate systems demonstrates that our refined results can better capture the relation between the Zipf''s and Heaps'' exponents.

Conclusions/Significance

The present analysis provides a clear picture about the relation between the Zipf''s law and Heaps'' law without the help of any specific stochastic model, namely the Heaps'' law is indeed a derivative phenomenon from the Zipf''s law. The presented numerical method gives considerably better estimation of the Heaps'' exponent given the Zipf''s exponent and the system size. Our analysis provides some insights and implications of real complex systems. For example, one can naturally obtained a better explanation of the accelerated growth of scale-free networks.     

Differences in the exploitation of bream in three shallow lake systems and their relation to water quality

SUMMARY 1. The development of bream populations, water transparency, chlorophyll‐a concentration, extent of submerged vegetation and densities of the zebra mussel, Dreissena polymorpha, were analysed in three shallow eutrophic lake systems subject to different fish management. 2. In Lake Veluwemeer, the bream population was reduced from c. 100 to 20 kg ha^?1 after 5 years of fishing. The mortality caused by the fishery was estimated at 38% of bream >15 cm in addition to a 13% natural mortality of bream >17 cm. The decline was followed by an expansion of the Chara beds present in the shallow parts, an increase in water transparency in the open‐water zone, an increase in the density of zebra mussels and a decrease in chlorophyll‐a concentrations. 3. The newly created Lake Volkerak showed trends opposite to those in Lake Veluwemeer. Bream colonised the lake in 1988 and reached a biomass of c. 140 kg ha^?1 in 1998. The water transparency decreased from a maximum of 3 m to c. 1 m and the chlorophyll‐a concentration increased from 5 to 45 μg L^?1. Submerged vegetation colonised up to 20% of the total lake area in the first 5 years after creation of the lake in 1987 but decreased to 10% as turbidity increased. 4. Seine fishery in the Frisian lake system did not appear to affect the bream population despite annual catches as high as 40–50 kg ha^?1. The estimated natural mortality of fish >15 cm was 15% and mortality by fishery was 26%. The high loss was apparently compensated by good recruitment and high growth rates resulting from a c. 1 °C higher water temperature during the years when bream were removed by fishing. There was only a slight decrease in chlorophyll‐a concentrations and a slight increase in water transparency. 5. The results of this study suggest that the effects of bream exploitation in eutrophic lakes can vary depending on the efficiency of the fishery, recruitment success and temperature regime. In the absence of fishery, bream dominated the fish community in the study lakes and apparently prevented D. polymorpha and submerged vegetation from establishing because of physical disturbance, enhanced internal P‐loading and resettling of resuspended sediments.     

Hypothalamic neurosecretion in relation to water deprivation in ploceids of arid and swampy zones

Parenteral administration of methylcellulose causes massive splenomegaly and hemolytic anemia in rats. The red pulp of the spleen is markedly cellular due mainly to: (1) large numbers of voluminous free macrophages containing methylcellulose-induced vacuoles, (2) an increase in the number of plasma cells and (3) stasis of blood evidenced by a large number of erythrocytes and platelets in vessels, sinuses and cords. White pulp changes are usually less marked. Here the major change is the presence of macrophages containing methylcellulose-induced inclusions. The slow circulatory time in the spleen and the increase in macrophages may cause the hemolytic anemia observed in these animals.     

The logical structure of dreams and their relation to reality.

The contradictions and non sequiturs often found in dreams (or, equivalently, dream-narratives) are not in fact logical errors, but express and work with a type of logic that characterizes the deepest dimensions of our waking reality. These are the dimensions in which we deal with ourselves as a whole, our lives as a whole, or with the sense of reality as a whole. We do so, for example, in situations of deep personal transformation, or of recognition of deep difference of outlook. The paper argues that the logic of these situations is validly one of contradiction and non sequitur, that dreams sometimes express and work with these kinds of situations, and that these kinds of dreams therefore validly involve the same kind of logic. These kinds of dreams consequently also express insight into the sense that our lives or existence as a whole has for us. In achieving that insight, they actively orient, situate, or resituate us in our relation to our lives or existence as a whole. In this respect they are in themselves a practice of philosophy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assembly and breakdown of Cajal bodies in accessory nuclei of Hymenoptera

In some species of insects, oocytes have vesicular organelles, termed accessory nuclei (ANs). The ANs form by budding off from the nuclear envelope of the oocyte and are filled with translucent matrix containing dense inclusions. One type of these inclusions contains coilin and small nuclear ribonucleoproteins (snRNPs) and is homologous to Cajal bodies. We describe the early events in the morphogenesis of Cajal bodies in the ANs (ANCBs) of the common wasp, Vespula germanica, and show that they contain survival of motor neurons (SMN) protein. We present evidence that in the wasp, ANCBs form by the gradual accumulation of aggregates composed of SMN and small nuclear RNAs. We also show that ANCBs break down and disperse within the ANs as the ANs, which initially surround the oocyte nucleus, localize to the oocyte cortex. The components of dispersed ANCBs are retained within ANs until the end of oogenesis, which suggests that their function may be required at the onset of embryonic development. Because the morphology and behavior of ANs and their Cajal body-like inclusions are conserved in two other hymenopteran species, these features might be characteristic of all hymenopterans.