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PubMed1982

The explant culture of pig skin after corneocyte layer stripping in vivo.

Adult pig skin was stripped of its horny layer by cellophane tape. At intervals over the next 4 days explant cultures were prepared from such areas. Growth displayed an initial rapid and secondary slower phase. Plating of explants immediately following the stripping gave rise to an increased rate of migration of cells from the explants during the first growth phase but a decreased second or proliferative growth phase. This was not present when plating was delayed 1 to 4 days after stripping. The growth fraction in cells of the stripped skin explant cultures was similar to that of unstripped controls. The diminished growth rate of the cells was due to prolongation of the mean cell cycle time. Thus, the hyperproliferative state induced in vivo after stripping did not maintain itself when transferred in vitro. This result is of importance concerning animal models for psoriasis and the influence a transfer to in vitro conditions may have on the hyperproliferative psoriatic epidermis.

Animals↗

PubMed1979

Comparative ultrastructure and cytochemistry of epidermal responses to tape stripping, ethanol and vitamin A acid in hairless mice.

The responses of hairless mouse epidermis to tape stripping, ethanol and vitamin A acid were compared using electron microscopy and cytochemistry. Stripping the skin 4 times with cellophane tape removed most of the stratum corneum and caused the development of enlarged intercellular spaces and dense intramitochondrial inclusions. These changes began within an hour, reached a maximum by 24 hr, and subsided by about 4 days. There was also some accumulation of glycogen and the development of occasional basal lamina breaks and a few intracellular lipid droplets by 24 hr. Topically applied ethanol (95%) produced a similar response, though less damaging. In addition, ethanol induced the formation of numerous lipid droplets in the cytoplasm of keratinocytes by 24 hr and often caused sloughing of the stratum corneum. Vitamin A acid (3%) was dissolved in propylene glycol for application to the skin. We found the application of propylene glycol alone to produce no epidermal changes. Vitamin A acid produced mild damaging effects with small intercellular spaces and intramitochondrial inclusions, but no lipid droplets or glycogen were detected. Vitamin A acid also caused dramatic inhibition of keratinization by 24 hr. Intramitochondrial inclusions were digested by protease, indicating a protein component and they also stained with silver methenamine, indicating the presence of glycogen or glycoprotein.

Animals↗

PubMed1980

The rate of formation of corneocyte layers after stripping the noninvolved psoriatic skin and its relation to parakeratosis and epidermal enzyme levels.

Corneocyte layer formation rate using dansyl chloride as corneocyte marker was followed in noninvolved skin during a period of 2 weeks after that the skin had been subjected to cellophane stripping. The rate increased after stripping in 7 of 9 tested but it was not paralleled by any apparent parakeratosis. In 1 of 9 patients a Koebner reaction occurred. The corneocyte formation rate in the Koebner reaction was 6.1 times that of the noninvolved skin and with a degree of parakeratosis of 41%. In involved skin, a positive correlation, coefficient 0.81, was shown between corneocyte layer formation rate (range 3.9-15.2 layers/day) and degree of parakeratosis (range 24-100%). In the skin 5 to 14 days after stripping the rate of formation of the corneocyte layer varied from 1.6 to 8.2. In the noninvolved and involved skin the mean rate was 2.2 and 9.7, respectively. In the stripped skin epidermal glucose-6-phosphate dehydrogenase and pyruvate kinase activities generally were the same as those of the noninvolved skin. In the Koebner reacting epidermis the 2 enzymes were increased 2.2 and 1.1 times the noninvolved levels but were statistically not significantly increased from control values.

Adult↗

PubMed1988

Ecological studies on reovirus pollution of rivers in Toyama Prefecture.

Reoviruses (reos) were isolated from river water in various areas of Toyama Prefecture. The frequency of reo isolation was higher in the river water, the basin of which has a larger human population. The degree of river contamination with reo paralleled that with the Escherichia coli group of organisms, and reos were frequently isolated from sewage, too. The high antibody-positive (greater than or equal to 1:8 or greater than or equal to 1:10) rates against reos in humans and other animals tested (swine, cattle, and field rodents) indicated their wide-spread infection with reos. These results suggested that the major source of reos present in the river water may be the excretion by humans and other animals, especially the former. Survival experiments in which reos were added into the filtered or centrifuged river water and kept at various temperatures, revealed that reos survived for more than 3 years at 5 C. In the field experiment where reos suspended in cellophane tubes were kept in an agricultural water stream in winter (water temperatures below 10 C), they survived for 6 months until the water temperature rose above 20 C in summer.

Animals↗

PubMed1994

Characterization of hemolytic and antifungal substance, cepalycin, from Pseudomonas cepacia.

Hemolytic and antifungal substances, cepalycin I and cepalycin II, have been isolated from Pseudomonas cepacia JN106. A large amount of cepalycins were produced by growing the cells on 1% glycerin-nutrient agar medium covered with a cellophane membrane. The cell-washed supernatant was applied to an Amberlite XAD2 column, and cepalycins were eluted with 70% ethanol containing 1mM HCl. Cepalycins were separated by reverse phase HPLC in two fractions which were designated as cepalycin I and cepalycin II. The two cepalycins have indistinguishable UV absorption spectra but have different levels of hemolytic activity relative to the UV absorption. From the inhibition of hemolytic activity of cepalycin by sterols, both cepalycins were suggested to interact with cholesterol in erythrocyte membrane. Such an interaction may contribute to their hemolytic and antifungal activities.

Amphotericin B↗

PubMed1981

Transepidermal chloride flux through hydrated skin: combination chloride electrode.

A combination chloride electrode was used to determine quantitatively the outward rate of epidermal chloride transport in vivo. Regional anatomical variation and the effects of topical agents and cellophane tape strippings on the rate of chloride diffusion were determined. Transepidermal chloride flux through hydrated skin appears to be an alternative method for determining stratum corneum function in vivo.

Acetates↗

PubMed1982

Formation of UV-induced apoptosis relates to the cell cycle.

The relationship of the rate of epidermal proliferation to ultraviolet (UV)-induced cell death, namely sunburn cell (SC) formation, was investigated in vivo using the guinea-pig model. The number of SCs was correlated with (1) cellophane tape stripping which stimulates the proliferation rate and (2) treatment with antimitotic and antimetabolic agents which suppress the proliferation rate. The tape stripping performed 14 h before UV irradiation significantly increased the number of SCs counted 24 h after UV irradiation from a mean of 17.4 to 62.6 per section, and the tritiated thymidine (TdR-3H)-labelling index (LI) increased from a mean of 8.1 to 27.4%. SC counts and LI were markedly decreased by the intradermal injection of colchicine, methotrexate, hydroxyurea or 5-fluorouracil given once immediately after the tape stripping. The autoradiographic study showed that 23.2% of SCs were labelled when TdR-3H was given intradermally 1 h before UV exposure, while no SCs were labelled when TdR-3H was given immediately after UV exposure. The labelled SC count (23.2%) which presumably represents S phase cells at the time of UV exposure, was higher than the LI (mean 8.1%). These results suggest that proliferating cells, possibly S phase cells, may be responsible for SC formation.

Animals↗

PubMed1991

Surfaces of cryosections: is cryosectioning 'cutting' or 'fracturing'?

In order to determine if cryosectioning involves 'fracturing' or 'cutting' we examined the surfaces obtained in cryosectioning by a metal-replicating procedure commonly used in freeze-fracture microscopy. Platinum-carbon replicas were made of the surfaces of both the sections and the complementary surfaces of the sample stubs from which the sections were cut. When samples of frozen red cells were sectioned at -120 degrees C with large knife advancements (1 micron), the chips produced did not resemble sections. Membrane fracture faces, produced by splitting of the lipid bilayer, were found in electron micrographs of replicas of the sample stubs. This demonstrates that a cryomicrotome can be used to produce large intact replicas. When dull knives were used with small knife advancements, both smooth and fractured regions were found. The sections produced with dull knives had a snowflake appearance in the light microscope. When sharp knives were used with small advancements (0.1 microns), replicas of the surfaces were free of fracture faces and the sections had a cellophane-like appearance in the light microscope. Therefore, in cryosectioning a different process other than 'fracturing' is responsible. This 'cutting' process may be micromelting of a superficial layer by the mechanism of melting-point depression from the pressure exerted by the sharp edge of the knife.

Animals↗

PubMed2004

Independent genetic mechanisms mediate turgor generation and penetration peg formation during plant infection in the rice blast fungus.

The first barrier to infection encountered by foliar pathogens is the host cuticle. To traverse this obstacle, many fungi produce specialized infection cells called appressoria. MST12 is essential for appressorium-mediated penetration and infectious growth by the rice pathogen Magnaporthe grisea. In this study, we have characterized in detail the penetration defects of an mst12 deletion mutant. Appressoria formed by the mst12 mutant developed normal turgor pressure and ultrastructure but failed to form penetration pegs either on cellophane membranes or on plant epidermal cells. Deletion and site-directed mutagenesis analyses indicated that both the homeodomain and zinc finger domains, but not the middle region, of MST12 are essential for appressorial penetration and plant infection. The mst12 mutant appeared to be defective in microtubule reorganization associated with penetration peg formation. In mature appressoria, the mutant lacked vertical microtubules observed in the wild type. The mst12 mutant also failed to elicit localized host defence responses, including papilla formation and autofluorescence. Our data indicate that generation of appressorium turgor pressure and formation of the penetration peg are two independent processes. MST12 may play important roles in regulating penetration peg formation and directing the physical forces exerted by the appressorium turgor in mature appressoria.

Actins↗

PubMed2006

A gene involved in modifying transfer RNA is required for fungal pathogenicity and stress tolerance of Colletotrichum lagenarium.

7-Methylguanosine (m7G) modification of tRNA occurs widely in prokaryotes and eukaryotes, although information about its biological roles is limited. Here, we report that a gene involved in m7G modification of tRNA is required for infection by the phytopathogenic fungus Colletotrichum lagenarium. Analysis of the infection-deficient mutant of C. lagenarium, produced by plasmid insertional mutagenesis, identified a tagged gene that is designated APH1. The aph1 mutants, generated by targeted gene disruption, exhibit significant reduction in pathogenicity on the host plants. We conclude that APH1 is required for fungal infection in C. lagenarium. Aph1 showed a strong similarity to Saccharomyces cerevisiae Trm8 involved in m7G modification of tRNA. The m7G content of tRNA from the aph1 deletion mutant was severely reduced compared with that from the wild type, indicating that APH1 is required for m7G methyltransferase activity. Appressoria formed by the aph1 mutants developed penetration hyphae into cellophane, suggesting that appressoria of the mutants retain basic function for penetration. However, the aph1 mutants failed to develop intracellular penetration hyphae into epidermis of the host plants, suggesting a specific requirement of APH1 for appressorium-mediated host invasion. The mutants also had increased sensitivity to salinity and H2O2 stresses. Interestingly, a heat shock treatment on the host plants enabled the aph1 mutant to penetrate them. These data suggest that the APH1 is required for the plant invasion, probably to overcome environmental stresses derived from basal preinvasion (penetration) defence of the host plants.

Colletotrichum↗

PubMed1991

Latent herpes simplex virus reactivation in the guinea pig. An animal model for recurrent disease.

The purpose of this investigation was to establish an animal model by which latent herpetic disease could be mechanically reactivated, yielding an adequate number of recurrent clinical lesions in the guinea pig. To determine strain virulence, hairless guinea pigs were inoculated with three different strains of herpes simplex virus (HSV) using a spring-loaded multiple puncture apparatus. HSV-1 strains SC-16 and McKrae produced an average of 21 and 8 lesions per infected area, respectively. The HSV-2 strain (333) produced the lowest number at an average of 3 lesions per site. Following the determination of strain virulence, a larger number of guinea pigs, Hartley and hairless, were inoculated with the same HSV strains in a similar fashion as previously described. The primary infection was evident from 6 to 12 hours postinfection (PI) by the initial appearance of small pustules, which peaked by day 2, seen as dome-shaped fluid-filled sacs. These initial lesions burst, crusted (day 6 PI), and had resolved and flattened between days 9 and 12 PI. At 4-6 weeks PI the inoculated areas were stripped 6 times per area with cellophane tape. Recurrent lesions were seen in the majority of the stripped areas (89-100%). The best results were achieved with the HSV-1 (SC-16) strain in hairless guinea pigs, which peaked on day 3 poststripping, producing an average of 12.25 lesions per area. The hairless guinea pig is ideal for this type of experiment because its use eliminates the trauma associated with denudation, a procedure necessary when using haired (Hartley) animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1978

Alkaline chloride-free oxygen electrolytes.

The initial and long-term drift of tcPO2 microcathode electrodes has been shown to be substantially less when chloride is removed from the electrolyte, despite the probability that reference electrode EMF is less well defined. In addition to virtually eliminating drift, these electrolytes eliminate silver deposition on the cathode. The most successful electrolyte tested thus far has been 0.2 M K2B4O7 in 95% ethylene glycol, 5% water, both with and without cellophane spacers. The buffering produced by borate appears to prevent the downward drift in CO2 free air probably caused by Ag2 CO3 formation on the anode, after exposure to skin.

Blood Gas Analysis↗

PubMed1976

Replication of Escherichia coli DNA in vitro: inhibition by oxolinic acid.

Oxolinic acid, a quinolone antibacterial agent, inhibits reversibly the ATP-dependent replicative DNA synthesis in permeable cell systems as well as in cellophane disk lysates. It is about 10-fold more active than the structurally related nalidixic acid. Both drugs have no effect on the ATP-independent DNA repair, but interfere to some extent with RNA synthesis in permeable cells. They appear to interact with the same target since spontaneous nalidixic-acid-resistant mutants of nalA phenotype are also resistant to oxolinic acid. Full sensitivity to oxolinic acid can be conferred to lysates from resistant cells by addition of extracts from sensitive cells.

Adenosine Triphosphate↗

PubMed1980

Systemic and regional haemodynamics in experimental renal hypertension in conscious rabbits.

1. The radioactive microsphere method was used to measure the distribution of cardiac output, regional flows and resistances in conscious normotensive and hypertensive rabbits implanted with an electromagnetic flow probe on the ascending aorta or pulmonary artery. Hypertension was induced by wrapping one kidney with cellophane and removing the other, and studies were performed about 5 weeks later. 2. Heart rate, stroke volume, cardiac output and total renal mass were reduced in the hypertensive animals, while the weight of, and the cardiac output distribution to left ventricle and the remaining kidney were increased. 3. In renal hypertensive rabbits, the weight normalized regional blood flow was diminished in a number of tissues, including the kidney, and, except for some organs in the splanchnic area (stomach, small intestine, mesentery and pancreas) and the fat, there was a rather uniform increase in tissue vascular resistance.

Animals↗

PubMedDate not supplied

Systemic and regional haemodynamic responses to isoprenaline in conscious renal hypertensive rabbits.

1. Using the electromagnetic flow probe and the radioactive microsphere technique, systemic and regional haemodynamic variables were measured in conscious normotensive and hypertensive rabbits. The rabbits were made hypertensive by unilateral nephrectomy combined with cellophane-wrapping of the remaining kidney and systemic and regional haemodynamic effects of isoprenaline infusions (0.5 micrograms.kg-1 .min-1) were compared in the two groups of animals. 2. Isoprenaline evoked increases in heart rate and cardiac index while the total peripheral resistance decreased. In the hypertensive rabbits the effects were similar, except for a significantly more pronounced decrease in blood pressure. 3. Isoprenaline increased the fraction of the cardiac output delivered to the heart, skin and fat, at the expense of the fractions to the brain, stomach, small intestine, pancreas, liver and kidney(s) in both normotensive and hypertensive animals. Local peripheral resistance was decreased, most prominently, in the heart, skin, skeletal muscle and fat. 4. In the normotensive rabbits pretreatment with propranolol (4 mg.kg-1 infused in 1 h) effectively blocked the cardiovascular responses following isoprenaline infusion. 4. Since the systemic and regional haemodynamic effects of isoprenaline were not less (if anything, slightly more) in the hypertensive than in the normotensive rabbits, our results provide no evidence for subsensitivity of beta-adrenoceptors as a contributory factor in the development of hypertension in this model.

Animals↗

PubMed1986

Endothelium-dependent relaxation is unaltered by hypertension, cholesterol or intimal thickening.

The effect of cellophane wrap hypertension (WRAP) and hypercholesterolemia (1% cholesterol diet, CHOL) for 4 weeks was assessed on the endothelium-dependent vasodilator response to acetylcholine in conscious rabbits after pharmacological autonomic blockade. Dose-response curves for the hindlimb vascular resistance (ear artery pressure/lower aortic blood flow; Doppler flowmeter) and acetylcholine infusion (i.v.) doses were unaltered in sensitivity (ED50) for any of the treatment groups. The range and slope of the curves were significantly altered by WRAP, CHOL or WRAP plus CHOL for acetylcholine and adenosine infusions consistent with medial hypertrophy in resistance vessels and raised serum viscosity. The effect of intimal thickening on the response to endothelium derived relaxing factor (EDRF) was tested in dog carotid artery ring segments in vitro 4 weeks after endothelium removal. The relaxation responses to acetylcholine (EDRF-dependent) and adenosine or nitroglycerin were not significantly altered by the neo-intima. Therefore the response to EDRF released by acetylcholine in resistance vessels was unaltered by hypertension, hypercholesterolemia or both together. Neo-intimal thickening in response to initial endothelium loss does not appear to alter EDRF responses in the carotid artery.

Animals↗

PubMed1986

Hypertension alters slope and range but not sensitivity to vasoconstrictor and vasodilator agents in the rabbit hindquarter.

The vascular reactivity (slope and range) and location parameter (ED50) of dose-response curves in the hindquarter vascular bed in conscious rabbits previously subjected to renal cellophane wrapping or sham operation were examined. The animals were instrumented with pulsed Doppler flow transducers and chronic indwelling aortic catheters for intra-arterial drug infusion. The rabbits were ganglion-blocked with mecamylamine before constructing full dose-response curves to intra-arterial infusions of methoxamine, noradrenaline, angiotensin II, acetylcholine, adenosine and serotonin. Curves relating dose to conductance were fitted to the experiments involving constrictors and curves relating dose to vascular resistance fitted to those involving dilator drugs. With both classes of drugs the reactivity was significantly higher in the hypertensive animals than in sham-operated rabbits. There was no difference in sensitivity (ED50 value) between the hypertensive and control animals for any agonist tested. The increased reactivity, but not sensitivity, could be entirely accounted for by the vascular amplifier action of medial hypertrophy in hypertension.

Animals↗

PubMed1960

Pharmacologically active peptides in the blood and urine of animals infected with Babesia rodhaini and other pathogenic organisms.

The blood and urine of mice and rats infected with Babesia rodhaini contain substances which stimulate the isolated guinea-pig ileum and rat duodenum. The amount of active material excreted increases as the infection increases. The active substances are stable to boiling with hydrochloric acid but not with alkali; they pass through a cellophane membrane and are soluble in hot ethanol. They are destroyed rapidly by papain and less rapidly by chymotrypsin, but are unaffected by trypsin or pepsin. Their action on smooth muscle is not affected by atropine, eserine, antihistamines, iproniazid, bretylium or by lysergic acid diethylamide. The active substances are probably peptides and there is evidence that the urine contains a mixture of peptides, some of which relax and some of which contract the rat duodenum. Similar active peptides appear in the urine of mice infected with Plasmodium berghei, Trypanosoma rhodesiense, Streptococcus pyogenes and Rift Valley fever virus.

Animals↗