Renoprotective differences between perindopril and enalapril in the diabetic hypertensive rat do not reflect glomerular angiotensin-converting enzyme activity

1. The various angiotensin-converting enzyme inhibitors have structural differences which affect their affinities for the catalytic sites on converting enzyme. We postulated that such differences might result in differences in renoprotective efficacy. We investigated this in the diabetic spontaneous hypertensive rat. We also investigated whether these differences might reflect variations in glomerular or plasma angiotensin-converting enzyme activity. 2. One week after induction of diabetes, rats were started on antihypertensive therapy: enalapril, 10 mg.day-1.kg-1, or perindopril, 4 mg.day-1.kg-1, in the drinking water. After 3 months, the rats were killed, blood samples were taken and tissues were harvested. Angiotensin-converting enzyme activity in isolated glomeruli and plasma was measured by fluorimetric assay. Glomerular protein content was also determined. 3. Urinary protein excretion was significantly lower in perindopril-treated rats than in either controls (P < 0.0005) or enalapril-treated rats (P < 0.05). Glomerular protein content was also lower in perindopril-treated rats (P < 0.05 versus enalapril; P < 0.005 versus control). There was no difference in glomerular angiotensin-converting enzyme activity between the two inhibitors although both were lower than control values (enalapril P < 0.025; perindopril P < 0.025). Plasma angiotensin-converting enzyme activity was significantly lower in the perindopril group than in either control (P < 0.005) or the enalapril group (P < 0.01). 4. We conclude that in the spontaneous hypertensive rat with streptozotocin-induced diabetes, perindopril is more effective than enalapril in reducing proteinuria and glomerular protein accumulation. This difference does not result from differences in glomerular-converting enzyme activity.     

Influence of soft tissue on density and relative contrast between gutta-percha and dentin images. An in vitro study

Factor XII initiates the intrinsic coagulation cascade and may affect the fibrinolytic system. Routine coagulation tests used during cardiopulmonary bypass (CPB) are abnormal in factor-XII-deficient patients and are useless for monitoring anticoagulation in these patients. A factor-XII-deficient patient requiring CPB is described. The baseline celite activated clotting time (ACT) was greater than 1400 seconds and the thrombin time was 12.4 seconds (control, 11.9 seconds). Two units of plasma were given resulting in an ACT of 173 seconds. Following 300 units/kg of heparin and during CPB, the ACT ranged from 670-596 seconds with the thrombin time greater than 200 seconds. Plasma provides exogenous factor XII allowing an endpoint on the ACT test and may protect against possible postoperative hypofibrinolytic complications. A commercially available modified thrombin time may also be useful and provide an endpoint during high-dose heparinization.     

Amphetamine-induced behavior, dopamine release, and c-fos mRNA expression: modulation by environmental novelty

We have shown recently that the psychomotor activating effects of amphetamine in the rat are much greater when this drug is administered in association with environmental novelty than when it is given in a home environment. The main purpose of the present study was to explore the neural basis of this phenomenon. We found, using in situ hybridization of c-fos mRNA, that the pattern of neuronal activation in the cortex, in the caudate, in the shell and core of the nucleus accumbens, and in other subcortical structures was markedly different when amphetamine (2.0 mg/kg, i.p.) was given in association with exposure to environmental novelty relative to when it was given at home. In most brain regions the magnitude of c-fos expression was over two times greater in rats given amphetamine plus novelty than in rats given amphetamine alone. In contrast, an in vivo microdialysis study indicated that environmental novelty did not affect amphetamine-induced dopamine release in either caudate or nucleus accumbens. Furthermore, a unilateral 6-hydroxydopamine lesion of the mesostriatal dopamine system reduced amphetamine- but not novelty-induced c-fos expression. Finally, we found no differences in the amount of corticosterone secreted after exposure to novelty, amphetamine, or both, suggesting that corticosterone does not play a critical role in the ability of novelty to modulate amphetamine-induced psychomotor activation. In conclusion, it seems that environmental novelty alters the neurobiological effects of amphetamine independently of the primary neuropharmacological actions of this drug in the striatum.     

Detection of infectious disease agents in tissue by immunocytochemistry

1. Immunocytochemical procedures have played an increasingly larger role in the identification of infectious disease agents in tissue sections owing to the increased availability and specificity of antibody reagents, the great sensitivity of the methods, and the relative facility with which the studies are performed. 2. Immunocytochemical methods can be applied to routine formalin-fixed tissue for the detection of infectious agents such as viruses, bacteria, fungi, and protozoa among other microorganisms for diagnostic and research purposes.     

Prevention of postoperative adhesions by single intraperitoneal medication

Postoperative adhesions account for a significant morbidity after abdominal, gynecological, or cardiac surgery. A large number of compounds have been suggested to prevent such adhesions, but none is generally accepted. We have compared eight different substances that could be beneficial for the prevention of postoperative adhesions in a new standardized rabbit model with measurement of the areas of adhesion. In 10 groups of 20 rabbits an area of abrasion of the serosa of the ileum, the appendix, and the abdominal wall measuring 10,000 mm2 was created by an emery piston during celiotomy. The controls received no medication. The treatment groups received a single intraperitoneal administration of 1 ml per 100 g body wt of normal saline (NaCl), 5 mg taurolidine (T), 0.5 U plasmin/300 U DNase (PD), 2000 IU streptokinase/500 IU streptodornase (SS), 7 mg phosphatidylcholine (PC), 4 mg hyaluronic acid (HA), 7 mg sphingolipid (SL), 7 mg galactolipid (GL), or 0.5 ml tetrachlorodecaoxide (TCDO), respectively. Ten days later the extent of adhesions was quantified by morphometry. The total area of adhesions (+/- SEM) was found to be 1998 +/- 124 mm2 in controls. The application of NaCl reduced the adhesions to 1368 +/- 58 mm2, of T to 1012 +/- 48 mm2, of PD to 673 +/- 33 mm2, of SS to 360 +/- 44 mm2, of PC to 335 +/- 84 mm2, of HA to 328 +/- 76 mm2, of SL to 278 +/- 80 mm2, of GL to 261 +/- 67 mm2, and of TCDO to 240 +/- 45 mm2. The effects of PD, SS, PC, HA, SL, GL, and TCDO were significant in comparison to controls and NaCl. Our experimental data suggest that the two new lipid substances, SL and GL, are the most likely candidates for routine clinical use in the prevention of postsurgical adhesions.     

Further molecular characterization and stability of the live oral attenuated cholera vaccine strain CVD103-HgR

Vibrio cholerae CVD103-HgR, the first live attenuated vaccine licensed for human use produced by recombinant DNA technology, was genetically compared to its parent strains 569B and CVD103. The genetic stability for both lyophilized vaccine in final container form and for viable organisms shed from vaccinees was determined. Results obtained lead us to conclude: (i) the genetic composition of the examined genes in CVD103-HgR is identical to that of the parent strains except for the alterations induced; (ii) the level of mercury resistance depends on the orientation of the mer operon within hlyA, with the highest level being observed for the orientation found in CVD103-HgR; (iii) no DNA sequences from plasmids used in construction remain in the genome; (iv) the strain is genetically stable; and (v) both CVD103-HgR and its parent strains contain defective lysogenic prophages. We have further confirmed that a certain amount of restriction fragment length polymorphism (RFLP) exists around the chromosomal ctx locus within V. cholerae strains of the classical biotype (detectable on chromosomal DNA restricted by either HindIII or EcoRI, but not PstI).     

Apoptosis and related proteins in different stages of human atherosclerotic plaques

BACKGROUND: The transition of a fatty streak into an atherosclerotic plaque is characterized by the appearance of focal and diffuse regions of cell death. We have investigated the distribution of apoptotic cell death and apoptosis-related proteins in early and advanced atherosclerotic lesions. METHODS AND RESULTS: Human atherosclerotic plaques were studied by whole-mount carotid endarterectomy specimens (n=18). This approach allowed comparison of adaptive intimal thickenings, fatty streaks, and advanced atherosclerotic plaques of the same patient. The fatty streaks differed from adaptive intimal thickenings by the presence of BAX (P<0.01), a proapoptotic protein of the BCL-2 family. Both regions were composed mainly of smooth muscle cells (SMCs), and macrophage infiltration was low and not different. Apoptosis, as detected by DNA in situ end labeling (terminal deoxynucleotidyl transferase end labeling [TUNEL] and in situ nick translation) was not present in these regions. Apoptosis of SMCs and macrophages, however, was present in advanced atherosclerotic plaques that were present mainly in the carotid sinus. A dense infiltration of macrophages (5.8+/-3% surface area) was present in these advanced atherosclerotic plaques. Cytoplasmic remnants of apoptotic SMCs, enclosed by a cage of thickened basal lamina, were TUNEL negative and remained present in the plaques as matrix vesicles. CONCLUSIONS: We conclude that SMCs within human fatty streaks express BAX, which increases the susceptibility of these cells to undergo apoptosis. The localization of these susceptible SMCs in the deep layer of the fatty streaks could be important in our understanding of the transition of fatty streaks into atherosclerotic plaques, which are characterized by regions of cell death. Matrix vesicles are BAX-immunoreactive cytoplasmic remnants of fragmented SMCs that can calcify and may be considered the graves of SMCs that have died in the plaques.     

Evidence for sexual differentiation of glia in rat brain

It is well established that gonadal steroids mediate sexual differentiation of the brain via direct effects on neurons during a restricted critical period. In addition, estrogen can influence glial morphology in the adult brain, and in vitro studies suggest estrogen induces glial differentiation. However, there is a lack of in vivo evidence for steroid effects on glia during the critical period. We report here a hormone-mediated sexual differentiation of arcuate glia as early as Postnatal Day 1. Using glial fibrillary acidic protein immunoreactivity (GFAP-ir), we compared the responsiveness of astroglia in the rat arcuate nucleus among five hormonally different groups. The results indicate increased GFAP-ir cell surface area 24 hr after hormonal manipulation in castrate males compared to intact males, intact females (ANOVA; P < 0.01), and females injected with testosterone propionate (50 microg; ANOVA; P < 0.05). However, astroglia in intact males extended their processes significantly greater distances from the cell body compared to all other treatment groups (ANOVA; P < 0.01). The GFAP-ir cells were categorized into four distinct classes ranging from a simple bipolar to a fully stellate morphology. The frequency distribution of classes varied between groups with more stellate cells found in intact males. Finally, these sex differences in arcuate glia persisted into adulthood. We hypothesize that during the critical period, testosterone, or its metabolite estrogen, induce sexual differentiation of glia. We further hypothesize that in females glial cells remain partially undifferentiated and this may be important to glial plasticity seen in adult female arcuate.