Morphology of Ammon's horn of the rat hippocampus in tissue culture

The principles of morphogenesis of Ammon's horn of the neonatal rat hippocampus in tissue culture (area CA_1-2) were studied by light-optical and electron-microscopic methods. Analysis of 5-, 12-, and 21-day cultures revealed maturation of the hippocampal pyramidal cells in vitro, the development of a protein-synthesizing system, and synaptogenesis. The synchronous development of the synaptic structures, of the protein-synthesizing system of the cell, and of electrogenesis suggests that these are interconnected factors.Laboratory of Neurophysiological Mechanisms of Adaptation, Institute of Clinical and Experimental Medicine, Siberian Branch, Academy of medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 8, pp. 229–231, August, 1977.     

Tissue effects of methotrexate injected into the uterine horn of pregnant female rats

Methotrexate has been proposed as a treatment for unruptured extra-uterine pregnancy, but its effects on the tubal wall remain unknown. In order to analyse these effects, an experimental study was carried out on two groups of pregnant female rats, one receiving methotrexate (n = 8) and the other sodium chloride (n = 6). In both groups, a single intra-embryonic injection was performed in the uterine horn. The genital tract was prepared for histological examination. In all rats which received a single dose of methotrexate (5 mg per 100 g body weight) six days after mating and were killed nine days later, the labyrinthine part and the junctional zone of the placenta were necrotic at the site of the injection, with no embryonic development. The other parts of the genital tract were not visibly altered. In rats receiving sodium chloride and killed under the same conditions, necrosis of the placenta was observed at the site of injection in three animals. In the other three rats, a focal necrosis of the placenta was found, which was probably of mechanical origin. From this study, we conclude that methotrexate is efficient in killing normally implanted embryos and is, at least under light microscopy, non-toxic to the adjacent portions of the genital tract.     

Morphology of three strains of contagious equine metritis organism.

Examination of recently isolated cultures of three strains of Contagious Equine Metritis Organism grown on specially formulated, serum-free, clear typing medium revealed the presence of numerous colonial opacity variants. These colonies were prepared by a number of fixation and staining techniques and examined by scanning and transmission electron microscopy. Opaque and transparent phenotypes produced copious amounts of extracellular material compared with intermediate-opacity phenotypes which produced little or none. Also unique to intermediate colonies were numerous thin intercellular strands, which may represent pili or polymers of extracellular material. The presence of an unusual fibrillar layer (with similar electron density to the extracellular material) on the outer leaf of the outer membrane also was confirmed. A number of other ultrastructural features also were noted, including an epilayer, a thin nonmembranous layer which covered colonies and adjacent agar.     

Morphology of inhibitory and excitatory interneurons in superficial laminae of the rat dorsal horn

If we are to stand any chance of understanding the circuitry of the superficial dorsal horn, it is imperative that we can identify which classes of interneuron are excitatory and which are inhibitory. Our aim was to test the hypothesis that there is a correlation between the morphology of an interneuron and its postsynaptic action. We used in vitro slice preparations of the rat spinal cord to characterize and label interneurons in laminae I–III with Neurobiotin. Labelled cells ( n = 19) were reconstructed in 3D with Neurolucida and classified according to the scheme proposed by Grudt & Perl (2002) . We determined if cells were inhibitory or excitatory by reacting their axon terminals with antibodies to reveal glutamate decrboxylase (for GABAergic cells) or the vesicular glutamate transporter 2 (for glutamatergic cells). All five islet cells retrieved were inhibitory. Of the six vertical (stalked) cells analysed, four were excitatory and, surprisingly, two were inhibitory. It was noted that these inhibitory cells had axonal projections confined to lamina II whereas excitatory vertical cells projected to lamina I and II. Of the remaining neurons, three were radial cells (2 inhibitory, 1 excitatory), two were antennae cells (1 inhibitory, 1 excitatory), one was an inhibitory central cell and the remaining two were unclassifiable excitatory cells. Our hypothesis appears to be correct only for islet cells. Other classes of cells have mixed actions, and in the case of vertical cells, the axonal projection appears to be a more important determinant of postsynaptic action.     

Nociceptive and sympathetic innervations in the abaxial part of the cranial horn of the equine medial meniscus: an immunohistochemical approach

In athletic horses, diseases leading to lameness are of great importance due to the loss of performance and the resultant economic concerns. Although stifle lesions are frequent in the hindlimb, due to the large size and complexity of the joint, and although meniscal tears have been identified as the most common soft tissue injuries in this joint, little is known about the mechanism that causes the painful sensation and thus the lameness. The aim of our study was to highlight any peripheral fibres involved in meniscal nociception in five macroscopically sound cranial horns of the equine medial meniscus, which has been one of the most common sites reported for equine meniscal injuries. Immunohistochemical stainings were performed using antibodies against Substance P in order to identify nociceptive fibres; against tyrosine hydroxylase for detecting postganglionic sympathetic fibres; and against glial fibrillary acidic proteins in order to identify Schwann cells. Our work highlights for the first time the presence of nociceptive and sympathetic fibres in equine menisci. They were found in the abaxial part of the cranial horn of the equine medial meniscus. This study suggests that when the abaxial part is injured, the meniscus itself could be the source of pain. These findings could provide a better understanding of the clinical presentation of horses with meniscal injury and contribute towards improving therapeutic strategies to alleviate pain in cases of equine meniscal injury.     

Rupture of pregnancy in the communicating rudimentary uterine horn at 34 weeks

Pregnancy in the rudimentary horn is rare and represents a form of ectopic gestation. Despite advances in ultrasound, prenatal diagnosis remains elusive, with confirmatory diagnosis being made at laparotomy. Because of variable muscular constitution of the wall of the rudimentary horn, pregnancy can be accommodated until late in pregnancy, when rupture occurs manifesting commonly as acute abdomen with high risk of maternal mortality. The rudimentary horn may or may not communicate with the uterine cavity with majority of cases being non-communicating. We present a case of pregnancy in the communicating horn that was difficult to diagnose which ruptured at 34 weeks and a review of literature.      

Radiologic anatomy of the spinal dorsal horn at the cervical level (anatomic-MRI correlations)

The spinal dorsal horn is known for its important functional role in the field of transmission and modulation of sensory afferents. Because of this, the dorsal horn represents a target for numerous analgesic and antispastic procedures. Thus, it would be interesting to develop imaging dedicated to this spinal structure. The purpose of this study was to investigate the radiologic anatomy of the cervical dorsal horn by magnetic resonance imaging (MRI) (1.5T). The first step consisted in the validation of the anatomic information provided by MRI on 5 human cadavers. A spin-echo sequence (T2, 2000/45) enabled the demonstration of good correlations between histologic sections and axial MRI slices performed at the corresponding cervical levels. The second step was the <相似文献   

Follicular development in pregnant cows after the administration of equine chorionic gonadotropin (eCG): A new insight

The follicular development in the cow occurs in a wave-like pattern, and it takes place also during pregnancy. In the cow, Equine Chorionic Gonadotropin (eCG) is used for superovulation, but a decrease in total fertility has been reported, likely because of its immunogenic properties in species other than equine. In this regard, immune response has been implicated in follicular growth, ovulation, and placental development. So, aims of our study are to test the safety of eCG administered during pregnancy and characterize the ovarian activity, the quality of oocytes, the hormonal status, and interleukin levels in eCG-treated pregnant cows.     

Rupture of left horn of bicornuate uterus at twenty weeks of gestation

Rupture uterus in nulliparous patients is generally associated with mullerian anomalies. A case of 23 years primigravida with 19 weeks gestation presenting with features of rupture is reported here. Ultrasound helped in the diagnosis of left horn of bicornuate uterus. After exploration, right ruptured horn was excised. The incidence, diagnosis and management of such cases is discussed.     

Impaired thermoregulation in pregnant rabbits at term

Membrane potential and resistance measurements were carried out on segments of superfused mouse exorbital lacrimal glands by inserting two microelectrodes into neighbouring coupled cells.Short-lasting intracellular injections of Ca²⁺, by the method of microiontophoresis, caused membrane hyperpolarization and resistance reduction. These effects were also observed in the presence of adrenergic and cholinergic blocking agents. From the potential and resistance changes observed the null potential for the action of Ca²⁺ was calculated to be –50 mV.Short-lasting extracellular Ca²⁺ applications caused membrane hyperpolarization and resistance reduction, but these effects were blocked by a combination of atropine and phentolamine.Intracellular Ca²⁺ application mimics the action of adrenaline and acetylcholine on lacrimal acinar cells.     

Morphology of hypertrophied rat kidney at high altitudes

Changes in the relative mass of kidney and in the mitotic activity in cortex and medulla are compared in nephrectomized rats under the valley and high altitude conditions. The rate of compensatory processes is lower at high altitudes than in the valley. At high altitudes, kidney hypertrophy and mitotic activity of kidney cells are decreased. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 8, pp. 226–228, August, 1997     

Infection with equine herpesvirus 1 (EHV-1) strain HVS25A in pregnant mice

The abortigenic effects of equine herpesvirus 1 (EHV-1) strain HVS25A, given intranasally, were assessed in pregnant BALB/c, C57BL/6J and Quakenbush mice at day 16 of pregnancy. All EHV-1-infected BALB/c mice showed clinical signs typical of EHV-1-induced disease, together with evidence of abortion. However, although there were fetal and neonatal deaths in some C57BL/6J and Quakenbush litters, the respiratory and systemic effects of EHV-1 infection in the dams were inconsistent. BALB/c dams were then inoculated at day 15 of pregnancy with either EHV-1 or rabbit kidney (RK) cell lysate (controls) and animals were killed at days 1-5 post-inoculation (pi), i.e., before the occurrence of abortions. EHV-1-infected mice showed a significant fall in rectal temperature between days 1 and 2 pi and lost weight during the first 4 days pi, demonstrating a significant mean difference in weight gain from the control group at days 2, 3, 4 and 5 pi. Death in utero was seen in five of 90 fetuses of EHV-1-infected mice, but in no fetuses from RK-inoculated mice. On days 1, 2, 3, 4 and 5 pi, the fetuses from EHV-1-infected dams were significantly smaller than those from RK-inoculated dams. Congestion and necrosis of the middle layer of trophoblast and chorionic necrosis were observed in the placentae from EHV-1-infected dams and assessed by a scoring system. Virus was isolated rarely from the fetuses (1/73), placentae (3/72) and uteri (1/16) of EHV-1-infected dams, and only from those killed on day 1 or 2 pi. This indicates that, as in the horse, abortion caused by EHV-1 infection in mice is not necessarily a consequence of fetal infection but may be due to fetal compromise due to vascular effects on the placenta.     

Short-term modulation at synapses between neurons in laminae II-V of the rodent spinal dorsal horn

Unitary excitatory (EPSP) and inhibitory (IPSP) postsynaptic potentials (PSPs) were evoked between neurons in Rexed's laminae (L)II-V of spinal slices from young hamsters (7-24 days old) at 27°C using paired whole cell recordings. Laminar differences in synaptic efficacy were observed: excitatory connections were more secure than inhibitory connections in LII and inhibitory linkages in LII were less reliable than those in LIII-V. A majority of connections displayed paired-pulse facilitation or depression. Depression was observed for both EPSPs and IPSPs, but facilitation was seen almost exclusively for IPSPs. There were no frequency-dependent shifts between facilitation and depression. Synaptic depression was associated with an increased failure rate and decreased PSP half-width for a majority of connections. However, there were no consistent changes in failure rate or PSP time course at facilitating connections. IPSPs evoked at high-failure synapses had consistently smaller amplitude and showed greater facilitation than low-failure connections. Facilitation at inhibitory connections was positively correlated with synaptic jitter and associated with a decrease in latency. At many connections, the paired-pulse ratio varied from trial to trial and depended on the amplitude of the first PSP; dependence was greater for inhibitory synapses than excitatory synapses. Paired-pulse ratios for connections onto neurons with rapidly adapting, "phasic" discharge to depolarizing current injection were significantly greater than for connections onto neurons with tonic discharge properties. These results are evidence of diversity in synaptic transmission between dorsal horn neurons, the nature of which may depend on the types of linkage, laminar location, and intrinsic firing properties of postsynaptic cells.     

Granulated metrial gland cells at implantation sites of the pregnant mouse uterus

Summary A study has been made of the distribution of, and synthesis of DNA by, granulated metrial gland cells at implantation sites in the pregnant mouse uterus. Granulated cells were found in small numbers randomly distributed throughout the endometrium on day 41/2 of pregnancy. Subsequently cells of this type were lost from the antimesometrial and lateral decidua but increased dramatically in number in the developing decidua basalis. From day 71/2 granulated cells populated the mesometrial triangle to form the metrial gland. A high proportion of granulated cells was found to incorporate tritiated thymidine and the distribution of such cells is described. However, no granulated cells were found to incorporate tritiated thymidine at or after day 12 of pregnancy. In addition the loss of granulated metrial gland cells from the implantation site is described and is accounted for by degeneration in situ and also by migration via vascular channels. It is suggested that this latter route could be of functional significance.