Recent advances in the structure and function of the parathyroid gland in animals and the effects of xenobiotics

Parathyroid glands in animals consist of a single basic type of secretory cell concerned with the elaboration of one hormone. Parathyroid hormone is the principal hormone involved in the minute-to-minute fine regulation of blood calcium in mammals. A larger biosynthetic precursor of parathyroid hormone is first synthesized on ribosomes of the endoplasmic reticulum in chief cells. Pre-proparathyroid hormone is rapidly converted to proparathyroid hormone in the Golgi apparatus. Active parathyroid hormone is packaged into membrane-limited secretory granules that are stored in the cytoplasm until secretion is stimulated. Parathyroid cells in most animals store relatively small amounts of preformed hormone but are capable of responding to minor fluctuations in calcium ion concentration by rapidly altering the rate of hormonal synthesis and secretion. Recently synthesized and processed active parathyroid hormone may be released directly in response to increased demand and bypass the storage pool of mature secretory granules. Relatively few chemicals or experimental manipulations significantly increase the incidence of parathyroid tumors. Irradiation increases the development of parathyroid adenomas in rats and the incidence is modified by feeding diets with variable amounts of vitamin D. Parathyroid adenomas have been encountered infrequently following the administration of a variety of chemicals in 2-year bioassay studies in Fischer rats; however, the incidence increases dramatically when comparing 2-year studies to lifetime data.     

Sonography of the thyroid gland in practice and in the clinic

Nowadays, the ultrasound examination is considered to be the most important procedure in the morphological examinations of the thyroid gland and its importance can be compared to the value of the basal thyroid stimulating hormone level (b-TSH) estimation in the examination of the thyroid function. Both methods in their preliminary stages can already exclude morphological and functional changes. In case of a disease, sonography makes the selection of further investigation procedures possible, in regard to their necessity and urgency. The organ size (in all 3 dimensions); the relationship to neighbouring structures; the echo pattern or the blood circulation are sonographic informations, which offer the specialist, the thyroid clinic or the surgeon (all with their wide differences of aims) an excellent means in the exclusion; the diagnosis; the investigation and the treatment strategy of thyroid gland diseases.     

Cutaneous calciphylactic reactions in the mouse and the rat and the effects of diphosphonates on the reaction in the rat

Calciphylaxis is a local tissue calcific reaction at the site of an injection of challenger substance given a critical time period after the oral administration of a sensitizer substance such as dihydrotachysterol (DHT), vitamin D or parathormone. Cutaneous calciphylaxis is readily induced in the rat but not in the mouse and this may be because, in the latter, the challenger substance is absorbed rapidly by macrophages. In the rat the administration of 500 micrograms/0.1 ml of DHT followed after 24 h by the subcutaneous (SC) injection of ferric chloride (FeCl3) (30 micrograms/0.1 ml) is followed rapidly by calcification of the SC site. There is an early transient acute inflammatory reaction with the incrustation of collagen fibres by the iron salt and an apparent exudation of calcium and phosphate ions from the bloodstream. These ions also become associated with collagen fibres. Two days after injection macrophages and multinucleated giant cells become the dominant cells. Calciphylaxis is a useful experimental model of ectopic calcification and is associated with an initial hypercalcaemia. The diphosphonates ethane-1-hydroxy-1, 1-diphosphonate (EHDP) and dichloromethylene diphosphonate (Cl2MDP) are effective inhibitors of the calciphylactic reaction when administered prior to the initiation of the experimental procedure.     

Distribution of eye- and arm-movement-related neuronal activity in the SEF and in the SMA and Pre-SMA of monkeys

We analyzed neuronal activity in the supplementary eye field (SEF), supplementary motor area (SMA), and presupplementary motor area (pre-SMA) during the performance of three motor tasks: capturing a visual target with a saccade, reaching one arm to a target while gazing at a visual fixation point, or capturing a target with a saccade and arm-reach together. Our data demonstrated that each area was involved in controlling the arm and eye movements in a different manner. Saccade-related neurons were found mainly in the SEF. In contrast, arm-movement-related neurons were found primarily in the SMA and pre-SMA. In addition, we found that the activity of both arm-movement- and saccade-related neurons differed depending on the presence or absence of an accompanying saccade or arm movement. Such context dependency was found in all three areas. We also discovered that activity preceding eye or arm movement alone, and eye and arm movement combined, appeared more often in the pre-SMA and SEF, suggesting their involvement in effector-independent aspects of motor behavior. Subsequent analysis revealed that the laterality of arm representation differed in the three areas: it was predominantly contralateral in the SMA but largely bilateral in the pre-SMA and SEF.     

Role of noradrenaline and serotonin in the basolateral region of the amygdala in food preferences and learned taste aversions in the rat

First, it was confirmed that bilateral lesions in the basolateral region of the amygdala (ABL) of the rat increased the time spent eating novel as compared to familiar food in a food preference test, and that the lesions impaired learned taste aversion to a sucrose solution which had been paired with lithium chloride. Then the roles of noradrenaline and serotonin in the amygdala in these aspects of food intake were investigated. In Experiment 2, it was shown that injections of 10 and 20 nmoles of noradrenaline (NA) into the ABL increased the time spent eating familiar food in the food preference test. Higher doses of NA (50 and 100 nmoles) increased the total time spent eating without changing the preference of the rats for familiar or novel food, and produced behavioral side effects. Serotonin (5HT) injected into the ABL in doses of 10, 50 and 100 nmoles did not modify the pattern of choice of the foods. In Experiment 3, it was shown that depletion of NA in the ABL with 10 micrograms 6-hydroxydopamine did not alter the level of feeding of novel and familiar foods, but did impair taste aversion Depletion of 5HT in the ABL with 10 micrograms 5,7 dihydroxytryptamine did not alter food preferences or impair the taste aversion learning. The depletions of NA and 5HT were confirmed biochemically. These results provide further evidence for a role of the amygdala in preferences for novel as compared to familiar foods and in learning that the ingestion of a food is associated with sickness, and suggest that noradrenaline but not serotonin in the amygdala is involved in these types of control of food intake.     

Changes in the ultrastructure of the myocardium after fibrillation and in the process of autolysis

Ultrastructure of the myocardium in the experiment was studied just after the heart ventricular fibrillation and 3 h after the animal death; the results were compared to those obtained by studying ultrastructure of human myocardium in patients dying from myocardial infarction complicated by ventricular fibrillation. The similarity of ultrastructural and autolytic changes was revealed in both series of observation. Overcontraction of myofibrils and redistribution of the mitochondria in cardiomyocytes, increase of the sarcoplasmic reticulum vesiculation, oedema of sarcoplasm, structural alterations of intercalative discs, later appearance of the symptoms of the irreversibility of lesions in the mitochondria and early penetration of colloidal lanthanum particles in rigor cells may serve ultrastructural diagnostic symptom of ventricular fibrillation. A better preservation of Purkinje's cells as compared to the contractile cardiomyocytes is also demonstrated.     

The Beauty of the Network in the Brain and the Origin of the Mind in the Control of Behavior

Behavior is not adequately described as a stimulus-response process. It is initiated by the animal and is generated because of its expected outcome in the future. The outcome can be good or bad for the animal. The brain is in charge of the selection process. This is the basic function of the brain. Taking Drosophila as a study case, this paper discusses initiating activity, several examples of outcome expectations, trying out (the internal search for a suitable behavior), chaining of actions, and the functional roles of chance in action selection. It takes mental processes and states such as goals, intentions, feelings, memories, cognition, and attention as higher levels of behavioral control that have their origin in biological evolution.     

Thermosensitive units in the tongue and in the skin of the duck's bill

Summary Thermosensitive units resembling cold receptors were found to be innervated by ramus ophthalmicus and ramus maxillaris, branches of nervus trigeminus and by ramus lignualis, a branch of nervus glossopharyngeus. Units were localized in the bill's skin and in the tongue of the duck. They very likely correspond to intraepidermal free endings.     

食管癌血管内皮生长因子和受体的表达及在癌转移中的作用

目的观察人食管癌组织和淋巴管中血管内皮生长因子(VEGF-C)及其受体-3(VEGFR-3)的表达,探讨食管癌的淋巴道转移机制。方法取临床手术切除的食管癌组织,用免疫组化方法检测人食管癌早期和进展期癌细胞或淋巴管对VEGF-C及其VEGFR-3的表达情况。结果在食管癌的癌细胞中可见VEGF-C阳性表达,阳性颗粒主要定位于肿瘤细胞胞浆内。淋巴管内皮细胞仅见VEGFR-3阳性表达,VEGFR-3在血管和癌细胞中也存在少量阳性表达。进展期食管癌VEGF-C和VEGFR-3的表达率和表达强度均强于早期。结论食管癌癌细胞VEGF-C的表达和淋巴管内皮细胞上VEGFR-3的表达均与肿瘤进展呈正相关,推测VEGF-C通过受体VEGFR-3促进食管癌组织淋巴管生成,从而引起癌淋巴道转移。     

Cholinergic mechanisms of the medial preoptic areas of the hypothalamus in the control of thermoregulation and the states of sleep and waking in pigeons

Cholinergic mechanisms in the medial preoptic area of the hypothalamus were found to be involved in controlling the time characteristics of the states of sleep and waking, as well as measures of thermoregulation, in pigeons. Muscarinic and nicotinic cholinergic receptors were involved in the mechanisms maintaining waking. Activation of muscarinic cholinoreceptors in the medial preoptic area was accompanied by increases in brain temperature due to increases in peripheral vasoconstriction and decreases in the level of muscle contractile activity. Activation of nicotinic cholinoreceptors in this area led to decreases in brain temperature and increases in the level of contractile muscle activity. Comparative analysis of the results of experiments and previous studies showed that changes in brain temperature in pigeons occurring on activation of cholinoreceptors depend on the type of cholinoreceptor activated but are independent of their location in the preoptic area of the hypothalamus. Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 94, No. 6, pp, 681–688, June, 2008.     

Neurosecretion in the hypothalamic nuclei and the changes in the concentration of thyroid hormone

Summary A study was made of changes in the rate of secretion in the supra-optic and paraventricular nuclei of rabbits in relation to thyroid concentration in the body. Changes in the hormonal balance were induced by thyroidectomy and by the administration of thyroidine or of 6-methylthiouracil.Hypothalamic secretion in the control animals was fluctuating, i.e., a phase of secretion was followed by one of evacuation and a shift of the secretory granules into the neurohypophysis. Accordingly the main mass of neurosecretion was present either in the cells of the paraventricular and supra-optic nuclei and in the median eminence, or in the posterior hypophyseal lobe.Treatment with thyroxin for 10 days led to an intensified production of the secretion in the hypothalamic nuclei, and to its accumulation in the neurohypophysis. Thyroidectomy or administration of 6-methylthiouracil decreased secretory activity by the cells, and caused a reduction in the store of neurosecretion in the posterior hypophyseal lobe.(Presented by Active Member AMN SSSR A. V. Lebedinskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 58, No. 7, pp. 102–106, July, 1964     

Ultrastructure of astrocytes in the cortex of the hippocampal gyrus and in the neocortex of the temporal lobe in experimental valproate encephalopathy and after valproate withdrawal

The aim of the study was to analyse the astrocyte ultrastructure within the hippocampal gyre cortex and neocortex of the temporal lobe in valproate encephalopathy induced by chronic administration of an anti-epileptic drug - sodium valproate (VPA) to rats for 1, 3, 6, 9 and 12 months, once daily intragastrically, in a dose of 200 mg/kg b.w. and after its withdrawal for 1 and 3 months. Prolonged application of VPA caused damage to protoplasmic astrocytes of the cortex regions examined, mainly in the pyramidal layer, which intensified in the later stages of the experiment, especially after 9 and 12 months. Ultrastructural alterations in astroglia during this experiment did not differ significantly between the hippocampal cortex and neocortex. The most pronounced astroglial abnormalities, concerning about 2/3 of protoplasmic astrocytes after 9 and 12 months, were characterized by considerable swelling of cells, with the presence of empty vacuolar structures in the cytoplasm, a substantial decrease in the number of gliofilaments or even their complete loss, which indicated fibrillopoietic failure of the cell, and the appearance of astrocytes showing phagocytic activity. The astrocytic changes coexisted with distinct damage to neurones and structural elements of the blood-brain barrier. One month after termination of chronic exposure to the drug, the abnormalities did not subside, whereas after 3 months features of distinct normalization could be observed in a considerable number, more than a half, of astrocytes. In valproate encephalopathy, apart from any direct effect of VPA and/or its metabolites on astrocytes, the main cause of the protoplasmic astroglial damage in the cortex of the CNS structures examined could be associated with changes in microcirculation in the cortex (vasogenic factor), leading to its ischaemia.     

HLA-B27等位基因和亚型与强直性脊柱炎关系研究进展

大量的研究证明,强直性脊柱炎(AS)是与人类白细胞抗原(HLA)相关性最强的疾病。AS的发病与HLA-B27阳性密切相关,并与B7、B13、B40等几个等位基因有一定关系。HLA-B位点有42个等位基因,其中HLA-B27具有高度多态性,含有22个以上的亚型,不同亚型的碱基序列间只有个别差异。B27亚型在AS患者中的分布因地区和种族上的差别而不同,在中国主要以B2704和B2705为主,但以B2705分布最广。这几年大量的人B27转基因鼠实验证明AS与B27的关联性。     

Developmental Changes in the Thickness of the Cortex and Its Layers in the Paramedian Lobule of the Cerebellum in Children

Neuroscience and Behavioral Physiology - Objective. To study developmental changes in the thickness of the cortex and its layers in the paramedian lobule of the cerebellum in children. Materials...     

Variations in the Thickness and Composition of the Skin of the Giraffe

This study examined the skin of two 1‐ to 2‐year‐old male giraffes and one adult male, determining skin thickness and histological structure with reference to it functioning as a component of the features required for the maintenance of blood pressure, dermal armor, or thermoregulation. It has been argued that a tight skin surrounding the extremities of the giraffe aids in the movement of fluid against gravity, hence preventing pooling of blood and tissue fluid (edema), but the skin has also been implicated in the thermoregulatory capacities and defensive anatomy of many mammalian species. In one of the younger giraffes, one‐half of the skin was analyzed from which close to 170 sites were measured. In the other young and adult giraffes, spot tests to confirm the pattern observed in the fully analyzed individual were undertaken. It was discovered that the skin varied in thickness across the entire body and within regions of the body. Histological evaluation revealed that the skin was mostly collagenous, although interesting patterns of elastic fiber densities were also apparent. The skin in the neck and legs exhibited a morphology that may assist in cardiovascular regulation of blood flow to and from the head and legs, and the skin of the trunk and anterior neck has the possibility of functioning in a protective role. The analyses performed could not add any new data regarding the thermoregulatory role already described for giraffe skin. Anat Rec 293:1615–1627, 2010. © 2010 Wiley‐Liss, Inc.     

Heterogeneous occurrence of aquaporin-4 in the ependyma and in the circumventricular organs in rat and chicken

Aquaporins are selective water channel proteins critical in volume homeostasis. In the CNS AQP4 predominates, localized mainly in the glia limitans, the perivascular endfeet and ependyma. The present immunofluorescent study reveals the distribution of aquaporin-4 in the circumventricular organs in rat and chicken brains. The ventricular ependyma (especially in the third one), the subfornical organ, the area postrema, the rat pineal body (in part), and the vascular organ of lamina terminalis were marked by intense immunopositivity. Several areas, however, proved to be immunonegative: the central canal, the subcommissural organ, the ependymal zone of the median eminence in rat but its whole thickness in chicken, the subtrochlear organ, and the paraventricular organ. The immunostaining of the lateral septal and subseptal organs were similar to their environment. Results on developing rats suggested that the aquaporin-4 immunonegativity is a secondary phenomenon. Surveying other structural and functional features, no clear explanation of the heterogeneous occurrence of aquaporin-4 was found. The absence of aquaporin-4 seems to correlate with some features of the “ependymal organs” (thickened, pseudostratified ependyma, presence of blood–brain barrier) and with the avoidance of GFAP. On the other hand, the organs rich in aquaporin-4 have features of the “hypendymal organs” (glial and vascular plexus but no blood–brain barrier). There are organs, however, which do not fit into either group completely, i.e. the lateral septal and subseptal organs. Presence of tight junctions coincides with the absence of aquaporin-4 in the ependyma of spinal cord, the subcommissural organ and the ependyma of median eminence.     

Age-related decreases in the concentration of Met- and Leu-enkephalin and neurotensin in the basal ganglia of rats

Previous studies using radioimmunoassay procedures have failed to show age-related changes in the concentration of Met- and Leu-enkephalin or neurotensin in rat basal ganglia. In contrast, using a combined high-pressure liquid chromatography (HPLC)-radioimmunoassay (RIA) technique we now report considerable decreases in the levels of these neuropeptides in areas of basal ganglia of 22 months old-compared to 3 months-old male Wistar rats. The concentration of Met-enkephalin was greatly reduced in the striatum and nucleus accumbens, but not in substantia nigra, of old compared to young animals. There was a similarly large decrease in Leu-enkephalin content in striatum of old rats with less marked decreases occurring in both the nucleus accumbens and substantia nigra. Neurotensin levels in the striatum and substantia nigra were greatly reduced in old rats, with a less marked decrease in the nucleus accumbens.     

Correlations between the state of the sympathico-adrenal and pituitary-adrenal systems and in the insulin level in horses in different situations

The blood levels of adrenalin, noradrenalin, ACTH, cortisol, and insulin and the urinary excretion of catecholamines were investigated in horses after physical exertion and exposure to emotional situations. The highest degree of activation of the sympathico-adrenal system (SAS) and the pituitary-adrenocortical system (PACS_, accompanied by a fall in the insulin level, was observed after training. A familiar emotional situation (the noise of the racetrack) activated both components of SAS and the PACS. An unfamiliar emotional situation (electronic music) evoked a distinct adrenal response. Correlation analysis showed that the inttial background level predermines future activation of the systems under the influence of powerful stimuli, Reciprocal relations between the hormonal and mediator components of SAS in the background state are converted into coordinated activation during training. Activity of one component of SAS regulates the degree of activation of the other component. Cross-correlation was found between activity of SAS and PACS and also between in the insulin and catecholamine levels during exposure to physical and emotional influences.Laboratory of Sport Endocrinology, All-Union Research Institute of Physical Culture, Moscow, K. I. Skryabin Veterinary Academy, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR S. E. Severin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 2, pp. 131–134, February, 1980.     

Changes in the oxygen tension of the brain and skeletal muscle in hyper- and hypocapnia

Summary Acute experiments were performed on cats under urethane anesthesia. A polarigraphic method was used to study the change of oxygen tension in the brain and skeletal muscle during hyper- and hypocapnia. Hypercapnia induced different oxygen tension changes in the different tissues: in the brain it was increased, and in skeletal muscle diminished. Hypocapnia caused by artificial hyperventilation caused the reverse changes: cerebral oxygen tension was reduced (whether hyperventilation was with air or oxygen), while that of the muscle was increased.It is suggested that the changes in the oxygen tension occurring in the tissue during hyper- and hypocapnia were mainly due to variations in the tissue blood supply.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 53, No. 2, pp. 3–8, February, 1962     

Morphologic characteristics of the changes in the thymus and spleen in alcoholism

Morphological studies of the thymus and the spleen were made in 54 alcohol addicts and 53 cases of other death cause at the age from 25 to 65 yr. Alcoholism was found to induce the reduction in thymus size and the number of its lobes with a simultaneous decrease of lymphocyte content in them; in the lymphatic follicles of the spleen (in the presence of infectious processes) absence of bright multiplication centres and alkaline phosphatase activity in their mantle zone cells was noted. There appeared to be a statistically significant difference in the amount of the parenchyma in the thymus of alcoholics (p less than 0.017) compared to that of the control group 0.68 +/- 0.09 g and 1.33 +/- 0.21 g, respectively and this figure was almost 4-fold less, than the average age norms, 0.26 +/- 0.03 g; the quantitative content of the splenic pulp in alcoholics also had a statistically significant difference compared to the control group (P less than 0.001), 6.37 +/- 0.66 g vs. 12.59 +/- 0.98 g, respectively. The data obtained indicate the development of immunodeficiency states in alcoholism and basing on the changes occurring in the thymus and spleen they can be referred to a combined T- and B-cell form of immunodeficiency.