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Reintroduction of Ca(2+)or modification of internal Ca(2+)stores by caffeine results in widespread irreversible injury. The adult golden hamster, however, is immune to such insult and the present report investigates the phenomenon. Isolated Langendorff perfused hamster and rat heart were subjected to 15 min Ca(2+)-free perfusion followed by 30 min of Ca(2+)perfusion at 37 degrees C. Caffeine was introduced during Ca(2+)-free perfusion in a number of experiments. Papillary muscles were processed for the ultra-structural study. The hamster heart did not exhibit the calcium paradox state whereas rat heart did. Hamster heart treated with caffeine either throughout or 5 min after starting Ca(2+)-free perfusion showed 70%+/-8 or 65%+/-8. 42 recovery, respectively, when Ca(2+)reperfusion was performed. Ultrastructure of muscle from both groups showed relaxed myocytes with slight disorientation of the sarcomere register. This disorientation was not seen in hamster hearts undergoing the conventional calcium paradox protocol. The hamster cardiac muscle is remarkably tolerant to [Ca(2+)]()i loading either induced by Ca(2+)reperfusion or caffeine-induced sarcoplasmic reticulum Ca(2+)release. Structural and functional characterization of Ca(2+)depletion and repletion in the hamster heart have been discussed., (Copyright 2000 Academic Press.)

Immune complexes play an important role in causation of renal lesions in various diseases. Circulating immune comlexes (CIC) are described in Kala azar. Role of CIC in pathogenesis of Kalaazar is discussed in present study. BALB/C mice were experimentally infected with L. donovani promastigotes. After visceralisation of infection, sera and kidneys of infected mice were preserved. Leishmanial antigen specific CIC could be demonstrated in 100% of infected mice by PEG ELISA, while they were absent in control mice. Ultrastructural pattern of renal lesions in infected mice showed presence of focal small electron dense deposits in glomerular basement membrane and subepithelial space, resembling immune complexes (humps). Rarely subendothelial and mesangial hypercellularity was present. These findings point towards a definite role of CIC in pathogenesis of renal lesions in Kalaazar.

Background: The purpose of this in vitro study was to evaluate the effect of CO2 laser on the periodontally involved root surface, and to compare its efficacy with citric acid, EDTA and hydrogen peroxide in removal of root surface smear layer after root planing., Methods: The study was conducted on 50 periodontally involved single rooted human teeth with poor prognosis. Immediately after extraction the teeth were scaled and root planed with Gracey curets; 50 specimens were obtained from the proximal side of each tooth which were assigned randomly to 1 of the 4 groups. Group A (35 specimens) was divided into 7 subgroups of 5 specimens each and irradiated with CO2 laser using a defocused mode at 3-watt power for 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, or 1.4 seconds, respectively. Groups B, C, and D (5 specimens each) were treated with 6% hydrogen peroxide, EDTA solution (pH 7.4), or saturated citric acid solution (pH 1), respectively for 3 minutes. The specimens were then fixed and scanned using SEM., Results: It was observed that surface smear layer was present on root surfaces of teeth that were root planed; the CO2 laser was not able to remove the smear layer on the sites that were irradiated for 0.2, 0.4 or 0.6 seconds at 3W power. Irradiation time of 0.8 seconds at 3W power was able to remove the smear layer, but the dentinal tubules were partially exposed. The surface irradiated for 1 second showed a flat appearance with many clear orifice of dentinal tubules. No change in diameter of exposed dentinal tubules was observed and their diameter was nearly equal that of normal dentinal tubules. Irradiation time of 1.2 and 1.4 seconds produced surface charring and carbonization and was totally ineffective in exposing the dentinal tubules; 6% hydrogen peroxide did not remove the smear layer completely and the exposed dentinal tubules orifice was not clear. EDTA (pH 7.4) and citric acid (pH 1) were found to be effective in removing the smear layer and exposing the dentinal tubules, which showed funnel shaped widening., Conclusions: Surface smear layer was present on root surfaces of teeth that were root planed. Laser irradiation of 1 second at 3W completely removed the smear layer with minimal change in the diameter of the dentinal tubules. EDTA and citric acid were also effective in removing smear layer, but the exposed dentinal tubules showed funnel-shaped widening.

During human embryonic development the process of differentiation begins in the cells covering the blastocyst, resulting in the formation of outer syncytial and inner cytotrophoblastic cell layers. Although the outer syncytial layer is known to be derived from the underlying layer of mononuclear cytotrophoblasts, the cellular mechanism involved in its morphogenesis is not clear. Furthermore, there is another type of cells, designated as intermediate trophoblasts, which play a vital role in syncytium formation. Using early first-trimester (6-10 weeks' gestation) human chorionic villi, a study was carried out to illustrate the ultrastructural features of these cells. It was observed that while there was a large number of coated vesicles, vacuoles, lysosomes and dense granules in the syncytiotrophoblast, in cytotrophoblasts there was a relatively smaller number. In intermediate cells, however, these organelles were more abundant. Moreover, a discontinuity in the plasma membrane along with gap junctions was frequently observed in these cells. Since these features represent the transitional stage of a differentiating cell, it is possible that the syncytiotrophoblast is in fact formed by the differentiation of intermediate trophoblasts.

Effect of antiestrogen ormeloxifene on progesterone-induced development of giant mitochondria in uterine glandular epithelial cells in ovariectomized adult Sprague-Dawley rats was investigated. Antiestrogen tamoxifen and antiprogestin onapristone were used for comparison. Well-formed giant mitochondria were observed in uterine glandular epithelial cells in rats treated with progesterone (20 mg/kg, subcutaneous [SC] per se for three consecutive days. In rats primed with estradiol-17 beta (0.5 micrograms/day, s.c.) on days-2 and -1 before progesterone treatment, there was, in addition, a marked increase and distension of smooth endoplasmic reticulum (SER) and Golgi complex, in comparison to extensive rough endoplasmic reticulum (RER) and polyribosomes in progesterone per se treated rats. Cytological picture in rats receiving single (1.25 mg/kg, day 1, p.o.) or multiple (0.25 mg/kg, days 1-3, p.o.) anti-implantation doses of ormeloxifene showed marked reduction in glandular epithelial cell height, luminal surface microvilli, RER, polyribosomes and cytoplasm:nucleus ratio, straightening of intercellular membranes, and interdigitation of basement membrane. Mitochondria were of normal size and nuclei were heterochromatic. Inhibition in the case of tamoxifen (0.1 mg/kg, days 1-3, p.o.) appeared partial and rare giant mitochondria with degenerating cristae and outer membranes were apparent. Onapristone (10 mg/kg, day 1, s.c.), in addition to inhibiting development of giant mitochondria, caused extensive vacuolization and distension of intercellular membranes in glandular epithelial cells.

We describe a family in which 2 sisters born to consanguineous parents developed childhood onset fibrosing pleuritis in association with constrictive pericarditis and bilateral deforming arthropathy of large and small joints of upper and lower extremities including flexion contractures of several fingers (camptodactyly) and toes. One patient also had mitral value prolapse. Histopathological examination of the synovium and pericardium revealed fibrosis, and ultrastructural study of synovium showed abundant inter and intracellular mesh of 9 nm microfibrils. We describe this distinct clinicopathological entity with pleiotropic manifestations, the common features of which appears to be the fibrosis of serous membranes. Therefore, the term "familial fibrosing serositis" is proposed for this entity.

In this study, viruria following Japanese encephalitis virus (JEV) infection in mice has been shown to appear earlier in pregnant than in normal mice with proteinuria and haematuria. This was related to the production of splenic macrophage derived neutrophil chemotactic factor (MDF) following JEV infection. Intravenous inoculation of MDF in mice resulted in leakage of cells, proteins and erythrocytes in the urine as a result of altered capillary permeability. The isolation of virus from kidney did not correlate with the shedding of virus in the urine. The histological examination of sections of kidneys showed no morphological damage; however, ultrastructural degenerative changes in the mesangial cells were observed following JEV infection. These data suggest that JEV-induced macrophage derived factor regulates the leakage of proteins, erythrocytes and cells into the urine.

Cell surface morphology of hamster decidual cells isolated from day 8 implantation swellings was studied, using both phase-contrast and scanning electron microscopy. Two kinds of cells, fibroblastic and epithelioid, were identified in cultures examined by phase-contrast microscopy. Fibroblastic cells were spindle-shaped, having pointed or blunt terminals on one end and bifid or webbed projections at the other end. Epithelioid cells, on the other hand, were flat and discoid, having a distinctively ruffled plasma membrane. Further, the plasma membrane of epithelioid cells formed rope-like or flange-like processes. The significance of such adaptations is discussed.

Alterations in nuclear and cytosolic estradiol (ER) and progesterone (PR) receptor concentration in the antimesometrial (AM) and mesometrial (M) segments of the uterus in relation to circulating hormone levels, histology and surface topography during the period of high endometrial sensitivity and development of trauma-induced decidualization in cyclic guinea pigs were investigated. The period of high endometrial sensitivity (i.e. day 5 of the estrous cycle) was characterized by elevated plasma estradiol and progesterone and their receptors in the nuclear and cytosolic fractions of the uterus. There was, however, no difference in the concentration of these receptors or the surface ultrastructure in the AM and M segments. Unilateral traumatization by scissor cut along the AM length of the uterus on day 5 of the estrous cycle induced decidual cell reaction resulting in a marked increase in weight of the decidualized (traumatized) uterine horn with advancing decidualization to reach maximum levels (926% of the contralateral nontraumatized uterine horn) 7 days after traumatization. This was associated with decidual transformation and a marked increase in nuclear and cytosolic ER and PR concentration in the AM segment of the traumatized uterine horn. An increase in receptor concentration in the M segment of the traumatized uterine horn or the AM segment of the nontraumatized uterine horn was transitory and of a low order. Receptor concentration in the M segment of the nontraumatized uterine horn remained low throughout days 8-12 of the cycle. Findings indicate a possible role of both estradiol and progesterone in induction of endometrial sensitivity and development and maintenance of decidua in the guinea pig.

Malaria infection in mice was produced by intraperitoneal inoculation of 10(6) erythrocytes parasitized with Plasmodium yoelii nigeriensis, a virulent strain of murine malaria. About one week after infection parasitaemia ranged between 60 and 80%, and 100% mortality was observed. Infected animals were killed 6 days after infection to allow the examination of brain tissue. Electron microscopical observations revealed marked damage to cerebral vascular vessel walls with separation of muscular layers, media and adventitia. The endothelial cell layer was discontinuous in places. Activated fibroblast cells producing collagen fibres were seen around the necrotic region of cerebral vasculature. Some parasitized erythrocytes were also seen attached to the endothelial cell lining. Cerebral oedema was prominent around the blood vessels.

Plasmodium yoelii nigeriensis infection in mice caused an increase in uptake of 125I-labeled bovine serum albumin, 51Cr-labeled erythrocytes and Evans blue dye from peripheral circulation into the brain. Isolated cerebral microvessels which were characterized in terms of their morphology under scanning electron microscope and enhancement of the specific activities of biochemical markers, viz. alkaline phosphatase, gamma-glutamyl transpeptidase, and monoamine oxidase, showed significant decrease in these activities due to P. yoelii nigeriensis infection. On the other hand, relatively minor (statistically insignificant) changes occurred in the first two enzyme specific activities in the cerebral cortex and monoamine oxidase registered an increase in this tissue due to infection. Histological examination of the cerebral tissue of infected animals by light and electron microscopy showed broken blood vessel walls and leakage of erythrocytes into extravascular space, some of which contained intraerythrocytic malarial parasite in a state of cell division.

Methyl [5-([4-(2-pyridinyl)-1-piprazinyl] carbonyl)-1H benzimidazole-2-yl] carbamate, a broad spectrum anthelmintic, was tested against Cysticercus fasciolaris in rats and the cysticercoids of Hymenolepis nana in beetles. A dose of 50 mg kg-1, given intraperitoneally (i.p.) to infected rats on 10 alternate days, was found most effective, killing all mature cysticerci. The same dose, given on each of five days, either from the fifth day prior to infection or the sixth day following infection, fully arrested the establishment of cysticerci. A single prophylatic dose of 500 mg kg-1, given intramuscularly (i.m.), protected rats against challenge with Taenia taeniaeformis eggs for 10 days. The test compound, mebendazole and praziquantel were all totally ineffective against mature cysticercoids in grain beetles but, of the beetles fed the drugs in flour, 66.3%, 50% and 83.8%, respectively, failed to support the development of immature cysticercoids. The effective cysticidal action of the compound makes it a candidate medical anthelmintic.

An ultrastructure study was carried out on the effect of a standard drug sodium stibogluconate and a newly identified active CDRI compound 87/305 [1,2-dimethyl-3-methoxy carbonyl-4-(2-nitro-4,5-dimethoxyphenyl) pyrrole] on amastigotes of Leishmania donovani in macrophage cells of spleen of infected hamsters. While Na-stibogluconate exerted its effect by activating the digestion capacity of host macrophages, compound 87/305 was directly lethal to the parasites without, exerting any effect on the host cells.

The action of phanquone on the incorporation of (14C)1-DL-valine and (14C)-8-adenine in TCA insoluble fractions of Entamoeba histolytica was examined as indices of RNA and protein synthesis respectively. The former was found to show greater sensitivity to the drug in terms of the effect manifested in the dose response curves for these parameters. Electron microscopic investigations with increasing concentrations of the drug demonstrated progressive vacuolization with concomitant dissolution of ribosomal helices. The drug had no significant effect on nucleus and plasma membrane even at concentration as high as 200 micrograms/ml.

The invasiveness of trophoblast cells is well known, but it is not clear whether they achieve this property by being transformed to other cell types (like malignant ones) or remain benign. Trophoblasts, in culture, were studied ultrastructurally by examining the surface morphology of the cell vis-à-vis their cytoplasmic outgrowth, and the presence and/or absence of ruffling membranes, filopodia, microvilli, pinocytotic pits or bleb-like structures was observed. Results revealed formation of ruffling membranes only on the leading edge, a presence of slender filopodia and pinocytotic pits but an absence of microvilli and bleb-like structures, the characteristic features of a transformed cell. The study indicated that the trophoblast cells, in spite of being invasive, do not convert to any other cell type.

Metronidazole (19 micrograms/ml) caused progressive increase in vacuolization in Entamoeba histolytica cells with disintegration of its plasma membrane leading to almost complete disappearance of the latter within 3 hours. The drug also induced formation of helical ribosomal aggregates in the cytoplasm and disappearance of button like structures inside the nucleus.

Studies on ultrastructure of drug-resistant strains of Plasmodium berghei have been mostly restricted to the experimentally selected chloroquine and pyrimethamine resistant strains. Study of the morphology of mefloquine and quinine resistant strain of P. berghei has been carried out to demonstrate some differences between normal and drug-resistant strains. The main differences are concerned with a complex physiological process i.e., food ingestion and digestion. E.M. studies reveal that in the sensitive strain of P. berghei the trophozoites possess numerous rod-shaped malarial pigment particles which lie within a vesicle. In the trophozoites of resistant parasites the malarial pigment particles are rarely visible. Trophozoites of the sensitive strain have only one large food vacuole while the trophozoite of the resistant parasite contains 2-3 smaller vacuoles.

The critical-point-dried specimens of Gastrothylax crumenifer (Creplin, 1847) Poirier, 1883 and Paramphistomum epiclitum Fischoeder, 1904, both recovered from the rumen of sheep, were studied by scanning electron microscopy at magnifications ranging from 10 to 10,000x to reveal the structural differences of the tegument between the two species. In G. crumenifer, both dorsal and ventral surfaces have tubercle-like tegumental elevations, devoid of spines. A row of prominent, regularly arranged, button-like protuberances encircle the rim of mouth. It is suggested that these are sensory in nature. The lining of the buccal tube also bears papillae, some of which appear balloon-like. The tegument near the outer acetabular rim is thrown into prominent ridges bearing groups of six to eight small papilla-like elevations. Towards the interior of the acetabular cavity this pattern merges into one with stout, finger-like projections with groups of papillae at their blunt tips. From their structure, these projections appear to aid strong anchorage to the host's surface and the papillae to be secretory. P. epiclitum has a similar tuberculated pattern on the dorsal and ventral surfaces. In the oral region, the tegument has some irregular, patch-like elevated areas. The acetabular surface is thrown into a pattern of deep folds and craters.

The ependymal structure of the fourth ventricle floor of adult rhesus monkeys was investigated using both scanning and transmission electron microscopy. Each half of the floor exhibited dense ciliation which decreased towards the median sulcus. The area postrema and the facial colliculus lacked cilia and were covered with non-ciliated ependymal cells. Along the entire length of the median sulcus supraependymal globular protrusions were seen. Over the rostral and middle thirds of the sulcus these protrusions exhibited interwoven ridges. At the former situation they were closely approximated but at the latter they were on the surface of non-ciliated nodules which were lying amongst sparsely ciliated cells. In the caudal third these protrusions presented smoother surfaces without any structural details over them. Transmission electron microscopy through the upper two thirds of the median sulcus revealed these surface protrusions to be non-ciliated cells having long and profuse network of interwoven microvilli over their luminal surface. These cell bodies exhibited well-defined supranuclear Golgi complexes, vesiculated rough and smooth surfaced endoplasmic reticulum, free ribosomes and polyribosomes, few electron dense granules, network of microtubules and light and dense multivesiculated bodies. These features suggested a secretory and/or absorptive role, rather that autophagy to these surface specialization.

The effect of nicotine on the ultrastructural changes and hormone contents of the neural lobe of the pituitary were studied in the rat. Nicotine caused a significant release of both vasopressin and oxytocin from the neural lobe. The examination of the neural lobe with electron microscope reveals the nerve terminals depleted of neurosecretory granules. These results suggest that a definite correlation exists between hormone contents and ultrastructural morphology.

The authors used the scanning electron microscope to study the surface ultrastructure of the ependyma in six control rabbits and six rabbits subjected to bilateral jugular vein ligation four to five days previously. Whereas in the control rabbits the mean CSF pressure was 27 mm H2O, it rose to 71.5 mm H2O in the experimental animals. The ependymal lining of the fourth ventricle, third ventricle and the inferior horn of the lateral ventricle was examined. In the experimental animals, clusters of cilia emanating from ependyma were separated. This appeared secondary to ingrowth of cell processes covered with microvilli. Remarkable alterations were seen in the dorsal and infundibular regions of the third ventricle. While a marked reduction in ciliary density and appearance of pits were noticeable in the former, almost total replacement of globular excrescences by pleomorphic microvilli was noted in the infundibular region. The morphological alterations in the ependyma that occurred in experimental animals suggested a modification in its function from a surface capable of propelling cerebrospinal fluid by ciliary movement to one capable of increased ependymoabsorption. Increased incidence of macrophage-like supraependymal cells was noted in the experimental rabbits.

The surface microtopography of Calicophoron papillosum (Stiles & Goldberger) and C. calicophorum (Fischoeder), inhabiting the rumen of sheep, has been studied by SEM. In C. papillosum, conspicuous transverse ridges encircle the mid-body, gradually lessening dorsally towards the posterior end. The general body surface is aspinose and smooth except for minute bead-like tubercles in the circumoral area. Two types of putative sensory structures-domed aciliate papillae and tegumental pits-are present. Their characteristic aggregation in certain regions and their distribution in other parts of the body is described. A unique pattern of ridges, confined only to the base of the genital papilla and the genital atrium, has been observed. In C. calicophorum, tegumental folds encircle the body, these are more numerous near the anterior end and fewer posteriorly. The oral area has numerous concentric folds with domed aciliate papillae; between or on the papillae are tegumental elevated pits from the centre of which a knob-like structure protrudes. These sensory structures occur to a lesser extent in the acetabular area.

Methyl 5(6)-(alpha-hydroxyphenyl methyl) benzimidazole-2-carbamate, a major metabolite of mebendazole was evaluated against Cysticercus fasciolaria (larval form of Taenia taeniaeformis) in rats. The metabolite was assessed in various doses. A regimen of 50 mg/kg x 10 (ip), given one day apart, was found to be most effective and killed all the mature cysticerci. On developing cysts, the treatment was initiated in two schedules; 5 days prior to (d-5 to d-1) and 5 days after (d + 6 to d + 10) administration of T. taeniaeformis eggs to rats. The later protocol with 100 mg/kg x 5 dose (ip) resulted in 95% inhibition in the establishment of cysticerci. Activity of mebendazole against mature cysts was parallel to metabolite whereas against developing cysts, it was inferior. The time related topographical changes that occurred in mature C. fasciolaris after treatment with metabolite (50 mg/kg x 10, ip, one day apart) were observed by scanning electron microscopy. There was loss of contractivity, gradual disappearance of microtriches and progressive degeneration of tegument. Similar changes were noticed with mebendazole. The possession of better efficacy and higher safety range [Indian J Exp. Biol, 25 (1987) 871], suggests that the metabolite can be a potential anthelmintic for man and animals.

The floor of the rat brain fourth ventricle has been divided into five zones to study the surface ultrastructure of the ependymal cells. Regional variations in the form of dense ciliation, sparse ciliation, central tufts of cilia, solitary cilia, pores, clavate and filiform microvilli have been observed.

Ancylostoma ceylanicum infection in golden hamsters (Mesocricetus auratus) caused marked biochemical and histopathological derangements. Jejunum, the primary site of infection, showed pronounced alterations compared with liver. Though the biochemical composition of jejunum was not significantly altered, activities of a few lysosomal enzymes were enhanced during hookworm infection. Marked damage to mitochondrial and microsomal membranes was reflected in changes in the activities of the marker enzymes from jejunal tissue. Lipid content, especially phospholipids and neutral lipids of hepatic tissue, exhibited marked elevation. Levels of hexokinase, phosphofructokinase, and lactate dehydrogenase were enhanced in jejunal as well as hepatic tissues, indicating activation of the glycolytic machinery during hookworm infection. A decrease in the levels of mucosal disaccharidases indicated damage to intestinal brush border membranes. However, alkaline phosphatase activity was increased in intestinal mucosa during the infection. Light microscopic examination of jejunal tissue revealed peeling off of the upper epithelial layer, activation of the goblet cells, and thickening of muscularis mucosa. However, hepatic tissue did not show gross alterations, except for slight necrosis in the centrilobular region.

RU-38486 or ZK-98734 treatment (3 mg/day, s.c.) to intact or hysterectomized adult female rats on Days 5-7 post coitum induced changes characteristic of luteolysis. Ultrastructurally, the luteal cells exhibited an extensive vacuolization of the cytoplasm and perinuclear areas, degeneration of mitochondrial cristae, massive accumulation of lipid droplets, increase in number of lysosome like granules and heterochromatinization of the nucleus. In general, RU-38486 induced more marked degeneration of the luteal cells than did ZK-98734. There was also a significant decrease in peripheral plasma progesterone concentrations in treated rats. We suggest that these antiprogestagens act via inhibition of luteal function in addition to their antagonism at the uterine progesterone receptor level.

The ontogeny of ookinete of Plasmodium berghei (NK 65) was studied in vector Anopheles stephensi fed on infected Mastomys natalensis. The round zygote transformed into an ookinete after passing through following stages-1 gram-seed shaped zygote, 2 comma-shaped stage, 3 semilunar and 4 banana shaped ookinete. Each fully formed ookinete had a 'Conule' at the anterior end of the body. In some ookinetes under SEM a depression was observed in the posterior half of the body. The function of the depression was not known.

Young adult inbred Swiss mice given single or repeated equitoxic doses of N-methyl-N-nitrosourea (MNUA) or methyl methanesulphonate (MMS) develop thymomas and pulmonary adenomas only following MNUA in spite of nearly identical overall alkylation of DNA of tumour target tissues by both agents due mainly to the biologically ineffective product 7-methylguanine. The main difference in DNA alkylation was the production of O6-methylguinine, a known pre-mutagenic product, by MNUA in amounts 10 or more times as large as following MMS. This supports the possibility that somatic mutations are a part of the process of carcinogenesis.

DDVP is an organophosphate pesticide whose neurotoxicity, in the form of cholinesterase inhbition, is well-known. Rats, weighing 200-225 g were given intraperitoneal injections of 3 mg/kg. DDVP daily for 10 days. Following perfusion-fixation, ultrathin sections of the cerebellum and spinal cord were examined with an electron microscope. A large number of electron-dense bodies exhibiting electron-lucid vacuoles were discernible in the perikarya of cerebellar neurons. Aggregations of mitochondria were also seen. Myelin-figures in dendrites and axons of the spinal cord were detected. Evidence of oedema was evident in the spinal cord.