Coronary artery narrowing in rats: mechanical alterations of left and right myocardium

To determine the effects of chronic coronary artery narrowing on myocardial contractile performance, nonocclusive constriction of the left coronary artery near its origin was surgically induced in rats and global cardiac hemodynamics, left and right myocardial mechanics, and the magnitude and distribution of tissue damage and interstitial fibrosis in the left ventricular wall were analyzed 1 mo later. Reductions in coronary artery luminal diameter of 55% resulted in left ventricular failure as characterized by decreases in systemic arterial pressures, systolic ventricular pressure, rise and decay in first derivative of left ventricular pressure (+/- dP/dt), and an increase in left ventricular end-diastolic pressure. Right side dysfunction was also present as documented by an elevation in right ventricular end-diastolic pressure and a reduction in -dP/dt. In vitro measurements of papillary muscle mechanics revealed a biventricular reduction in isometric developed tension and peak rates of tension rise and decay. Moreover, the kinetic parameters of isometric contraction duration, time to peak tension and time to one-half relaxation, were significantly shorter in left muscles from coronary artery-narrowed animals. Isotonically, peak muscle shortening was reduced in the left muscle, whereas time to peak shortening was prolonged in the right myocardium. In addition, the velocities of muscle shortening and relengthening were decreased in both ventricles. Foci of replacement fibrosis and diffuse interstitial fibrosis were found in the epimyocardium, midmyocardium, and endomyocardium, demonstrating that a significant amount of myocyte loss occurred throughout the left ventricular wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Activation of corticotropin-releasing factor-containing neurons in the paraventricular nucleus of the hypothalamus by interleukin-1 in the rat

Interleukin-1 (IL-1) alpha was injected into the lateral ventricle of the rat. An antiserum against Fos oncoprotein was used to detect the activated neurons immunohistochemically. A large number of neurons in the parvocellular paraventricular nucleus of the hypothalamus, in an area corresponding to the location of the corticotropin-releasing factor (CRF)-containing neurons, were strongly Fos-like immunoreactive (LI). Double immunostaining for Fos and CRF revealed that many of the Fos-LI cells were CRF-LI. Furthermore, the CRF-like immunoreactivity was greatly enhanced in the rats injected with IL-1 alpha, indicating an increase in CRF synthesis.

A comparative study of the treatment of unilateral fractured and dislocated mandibular condyles in the rabbit

This study evaluated the results of three methods of managing simulated unilateral dislocated fractured mandibular condyles in the rabbit. The first method consisted of surgical reduction of the fractured condyle to its anatomic position and its subsequent fixation with a titanium plate. The second method differed from the first by completely detaching the condyle, then replacing it as free graft. The third method left the fractured condyle in its dislocated position outside the glenoid fossa. Eighteen rabbits were used, 6 animals for each method. Half the animals in each group were killed at 4 weeks, the other half at 14 weeks postoperatively. Clinical, morphologic, functional, radiologic, and histologic examinations were conducted on all animals. The results indicated that open reduction with internal fixation with no disruption of the blood supply to the condyle provided the most favorable results. While closed reduction without internal fixation gave good functional results, definite reduction in ramus height on the operated site was observed in this group of animals. Animals that had open reduction and internal fixation using the condyle as a free graft did not do as well as the other two groups. Despite good mouth opening and occlusion, more animals showed facial asymmetry and it was more severe. None of the condyles were lost as result of necrosis, but healing took longer when compared with the other group of animals.

Analysis of proteins and lipopolysaccharides from Chinese isolates of Coxiella burnetii with monoclonal antibodies

Four Coxiella burnetii isolates in China and two reference strains were compared by SDS-PAGE and immunoblotting. The SDS-PAGE profiles of whole cells and LPS of Chinese isolates Qiyi, Xinqiao, and YS-8 were found closely related to Henzerling strain, and different from the Grita strain. In immunoblot assay of LPS and proteinase K-digested whole rickettsiae minor differences were seen in polysaccharide structure among the Chinese isolates by phase I monoclonal antibody. The present results suggest that the strains reported here may be divided into three groups according to the polysaccharide structure: Xinqiao and Henzerling strains (1), YS-8 and Grita (2), and Qiyi (3).

Ultrastructural characteristics of substance P-immunoreactive terminals in marginal division of rat striatum

In our previous work using immunocytochemical method combined with tract tracing techniques a new subdivision was described in the striatum of the rat. This "marginal division" is more densely filled with substance P, enkephalin and dynorphin B terminals than the rest of the striatum. In the present study, the synaptic organization of the substance P immunoreactive (SPIR) terminals in the marginal division of the rat striatum was studied using electron microscopy and immunocytochemistry for substance P (SP). Four major types of SPIR synapses were identified in the marginal division: axodendritic, axospinous, axo-axonal, and compound synapses. Axodendritic and axospinous synapses, in which the postsynaptic targets were small or large dendrites or spines, were the most common. A few axo-axonic synapses were observed as were several subtypes of compound synapses with more than two synaptic components. SPIR axon terminals formed the presynaptic components of all these synaptic types, but in one case an unlabeled bouton was observed making a synaptic connection onto a SPIR dendrite. Both symmetric and asymmetric SPIR synapses were observed in the marginal division. The vesicles in the SPIR presynaptic boutons were mostly pleomorphic although a few of them were round. The existence of asymmetric synapses, round synaptic vesicles and small postsynaptic dendrites distinguishes the ultrastructure of the marginal division from that of the other parts of the striatum. The complex characteristics of the synaptic organization in the marginal division implies that the SPIR terminals in the marginal division originate from a different source than those in the rest of the striatum. The complexity of the synaptic organization further suggests that the function of the marginal division is different from that of the rest of the striatum.

Fos expression in GHB-induced generalized absence epilepsy in the thalamus of the rat

Using the model of gamma-hydroxybutyrate (GHB)-induced generalized absence epilepsy, the present work investigated the distribution of fos oncoprotein expression in the rat thalamus with fos antibody immunohistochemistry. Thirty minutes after absence-like seizures, some fos-immunoreactive cell nuclei were found in bilateral thalamic paraventricular nuclei (PV). After a further 30 min, a massive bilateral induction of fos was observed in the lateral habenular nucleus (LHb), the PV, the rhomboid thalamic nucleus, and the intralaminar nuclei of the thalamus. These results suggest that the LHb and the midline and intralaminar thalamic nuclei may very likely be involved in the pathophysiology of absence seizures.

Hormonal actions during oocyte maturation influence fertilization and early embryonic development

On the basis of evidence just reviewed, the hormonal requirements during IVM of mammalian oocytes for fertilization and developmental competence may be summarized as follows: 1. Nuclear maturation occurs "spontaneously," without follicular factors or hormones, in all mammalian species. 2. Cumulus cells are necessary during nuclear maturation in culture for fertilization and developmental competence. Their effect is enhanced by the addition of serum or follicular fluid to the maturation medium. 3. FSH retards nuclear maturation, perhaps thereby enhancing subsequent developmental competence by allowing more time for cytoplasmic maturation to occur before fertilization. The effects of FSH are mediated, in part, by soluble factors from cumulus or granulosa cells. 4. FSH in vivo before culture or added in vitro to IVM culture media enhances fertilization and stimulates steroidogenesis (progesterone and estradiol) in cumulus cells. Blockade of steroidogenesis prevents the enhancing effect of FSH on fertilization. Progesterone can substitute for FSH in enhancing fertilization of rat oocytes. 5. Other hormones enhance beneficial effects of FSH, with some apparent species differences: a. Rat: Progesterone may mediate the FSH effect. b. Cow, rabbit: Estradiol enhances the beneficial effect of FSH. c. Rabbit: Prolactin further enhances the effects of estradiol and FSH. d. Human: No evidence is available on the possible synergism between steroids and gonadotropins in enhancing in vitro maturation. It is clear that further research is required to elucidate the mechanisms of action of all the hormones that have been observed to influence oocyte maturation, and to establish the physiologic significance of most of these, particularly in species other than laboratory rodents. Major benefits to animal production and human health are likely to accrue from such research.

Incidence survey of leukemia in China

A nationwide cooperative incidence survey of leukemia was carried out from 1986 to 1988 in a cooperative survey network covering 46 investigating areas. More than 60 million person-years were supervised and 1670 new cases identified. The annual incidence of leukemia was 2.76/10(5), and the 95% confidence interval of the population rate ranged from 2.63/10(5) to 2.89/10(5). The incidences in oil fields and polluted areas were significantly higher than those in other areas. The incidence of acute nonlymphocytic leukemia (ANLL) was 1.62/10(5); acute lymphocytic leukemia (ALL), 0.69/10(5); chronic myelocytic leukemia (CML), 0.36/10(5); chronic lymphocytic leukemia (CLL), 0.05/10(5); and special types, 0.03/10(5). The incidence and constituent ratio of CLL were significantly lower than those in Europe and America. A peak of ALL incidence before age 10 was seen; this rate then declined with increasing age until 30. However, the incidences of other leukemias rose with age, reaching peaks at old age (50-70). The leukemia rate in males was significantly higher than in females, both in youth (10-29) (caused by ALL) and at age old (mainly caused by ANLL). The incidences of ANLL subtypes (including M2b) are reported.