The hamster heart is resistant to calcium paradox.

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.

Immune complex mediated lesions in experimental Kala azar: an ultrastructural study.

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.

Effect of a carbon dioxide laser on periodontally involved root surfaces.

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.

Ultrastructure of intermediate trophoblast cells during morphogenesis of syncytiotrophoblast in early human pregnancy.

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.

Inhibition of progesterone-induced development of giant mitochondria in uterine glandular epithelial cells by an antiestrogen in rat.

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.

Correlation of pinopod development on uterine luminal epithelial surface with hormonal events and endometrial sensitivity in rat.

Intrinsic role of preovulatory and nidatory estrogen and progesterone and presence of viable blastocysts in utero in pinopod development on the uterine luminal epithelial surface and correlation between time of their development and onset of endometrial sensitivity were investigated. In adult rats, pinopods were observed on the entire epithelium even before secretion of nidatory estrogen, i.e. at 14.00 h on day 4 post-coitum (p.c.). Apparently, their number increased, more so on the antimesometrial than the mesometrial side, at 10.00 h on day 5, but were fewer and mostly collapsed at 10.00 h on day 6. Pinopods on day 4 were located within epithelial depressions and foldings, but protruded from the surface on days 5 and 6. Normal pinopods were also present on day 8 p.c. in rats under delayed implantation, but an implantation-inducing dose of estradiol-17 beta administered about 18 h earlier caused their collapse like that on day 6 in intact rats. Development and appearance of pinopods in intact or delayed rats was unaffected when native preimplantation embryos were prevented from entering the uterus. Normal pinopods were seen in immature rats receiving progesterone for at least 3 days or cyproterone acetate for 4 days, but not after estradiol alone. In animals receiving progesterone or priming/sensitizing estradiol in addition to progesterone, the decidual response was suboptimal, irrespective of the presence of pinopods on the day of stimulation. In animals in which a condition mimicking preimplantation had been produced by suitable hormone supplementation, optimal endometrial sensitivity and decidual response were elicited, even though most pinopods appeared collapsed, resembling those on day 6 in intact rats and about 18 h after estradiol in implantation-delayed rats. Findings confirm that pinopod development on uterine luminal epithelium was dependent on progesterone alone and demonstrate that: (i) preovulatory (priming) or nidatory (endometrial sensitizing) estrogen or viable blastocysts in utero have no role in their development. Nidatory estrogen, instead, appears to limit pinopod development by causing their collapse; (ii) pinopod development/presence on the endometrial surface might indicate the uterus coming into a period of sensitivity rather than actually being in it and might thus serve as a useful marker of "transfer window" rather than "implantation window"; (iii) in the rat, pinopod development might serve as an alternate assay for evaluation of progestational activity of newer test agents.

A syndrome of fibrosing pleuritis, pericarditis, and synovitis with infantile contractures of fingers and toes in 2 sisters: "familial fibrosing serositis".

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.

Viruria during acute Japanese encephalitis virus infection.

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.

Surface morphology of hamster (Mesocricetus auratus) decidual cells in vitro.

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.

Ultrastructure of cellular components of human trophoblasts during early pregnancy.

Two cell types, the cyto- and syncytio-trophoblasts, were identified in human chorionic villi of 6-10 weeks' gestation. The intracellular organization of these cells was examined. Ultrathin sections of small pieces of chorionic villi revealed the presence of a multinucleate syncytiotrophoblastic layer, whose surface was covered with microvilli. The cytotrophoblasts, however, had a single large nucleus with a prominent nucleolus. An interesting feature of the basement membrane of these cells was the presence of aggregates of dark granules in samples of the earlier gestational age (6-8 weeks) and granular bodies having a dense outer ring and a translucent inner ring with a lucid central area in samples of 8-10 weeks' gestation. Both types of granules are mineralized and are assumed to perform a buffering role for maintaining the neutrality of the layer.

Uterine estradiol and progesterone receptor concentration in relation to circulating hormone levels and histoarchitecture during high endometrial sensitivity and induced decidualization in guinea pigs.

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.

Neuropathological studies on Plasmodium yoelii nigeriensis-induced malaria in mice.

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.

Aberrations in cerebral vascular functions due to Plasmodium yoelii nigeriensis infection in mice.

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.

Substituted methyl benzimidazole carbamate: efficacy against experimental cysticercosis.

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.

Ultrastructural study on the antileishmanial effect of 1,2-dimethyl-3-methoxy carbonyl-4-(2-nitro-4,5-dimethoxyphenyl) pyrrole in hamsters.

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.

Biochemical and ultrastructural studies induced by phanquone on Entamoeba histolytica NIH-200.

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.

Ultrastructural morphology of ectoplacental cone trophoblasts of hamster embryos.

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.

Action of metronidazole on Entamoeba histolytica: an ultrastructural study.

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.

Ultrastructural comparison of erythrocytic stages of experimentally selected drug resistant strains of rodent malaria parasite P. berghei with its susceptible strain.

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.