Alteration of glomerular anionic sites by the development of subepithelial deposits in experimental glomerulonephritis in the rat

Using highly cationic polyethleneimine, alteration of glomerular anionic sites were evaluated ultrastructurally in two types of rat glomerulonephritis (GN); chronic serum sickness GN and heterologous (passive) or autologous (active) Heymann's GN. Daily i.v. injections of egg white lysozyme in physiologic saline into presensitized rats led to the formation of numerous mesangial and subepithelial deposits. In the non-proteinuric period in which immune deposits were localized predominantly in the mesangium, anionic sites of the laminae rarae and the epithelial cell coat were clearly observed. In the subsequent proteinuric period in which numerous subepithelial deposits were superimposed, a broad loss of anionic sites in the epithelial cell coat was seen. Splitting and focal loss of anionic sites on the lamina rara externa adjacent to the subepithelial deposits were commonly observed both in passive and active Heymann's GN and in lysozyme GN. These findings indicate that the subepithelial deposits are closely involved in the development of proteinuria by injuring the anionic sites, especially those on lamina rare externa of the glomerular basement membrane.     

Mechanism for Macrophage Activation against Corynebacterium parvum—Participation of T Cells and Its Lymphokines

It is well known that Corynebacterium parvum activates macrophages to produce tumor necrosis factor (TNF). It is suspected that the activation of macrophages by C. parvum requires T-cell participation. The purpose of this study was to confirm that T cells participate in the activation of macrophages by C. parvum. TNF production in vitro from the spleen cells of BALB/c- + / + mice was abrogated completely by the pre-treatment of spleen cells with anti-Ia antiserum and complement, indicating that Ia+ cells are the source of TNF. TNF production was not elicited at all in BALB/c-nu/nu mice. However, there was an increase in the number of Ia+ cells as well as an increase in the weight of spleen and liver. Supernatant from a culture of spleen cells stimulated with phytohemagglutinin-P (a PHA-induced lymphokine) made it possible for BALB/c-nu/nu mice to produce TNF, associated with an induction of Lyt-1⁺ cells and Lyt-2⁺ cells. However, treatment with the lymphokine did not augment the increases of Ia⁺ cells or liver and spleen weights. These results suggest that increasing the number of Ia⁺ cells is not sufficient to bring about TNF production; Ia⁺ cells must also be stimulated by T cells or T-cell lymphokines in order to produce TNF. These results suggest that T cells play an essential role in the activation of Ia⁺ cells against C. parvum.     

Hypotensive response of ethanol in rats pretreated with disulfiram or nitrefazole

The effect of disulfiram or nitrefazole pretreatment on ethanol induced hypotension was examined in urethane anesthetized rats. A relatively low dose of ethanol (150 mg/kg; i.p.) produced a characteristic hypotensive response in rats pretreated for various periods with disulfiram or nitrefazole. This hypotensive episode started 5-10 minutes following ethanol administration and lasted 40-60 minutes. The hypotensive response was not seen unless disulfiram or nitrefazole treatment preceded ethanol administration by a least 6-8 hours. The low dose of ethanol produced a plasma ethanol concentration of 10mg/100ml or less. One treatment with nitrefazole (200 mg/kg) rendered rats vulnerable to ethanol-induced hypotension for 6 but not 8 days. One treatment with disulfiram (200 mg/kg) lasted 4 but not 6 days. In addition, the hypotensive response was greater in rats treated with nitrefazole than in rats treated with an equal dose (200 mg/kg) of disulfiram.     

Chronobiologic Evaluation of Angiotensin-Converting Enzyme Activity in Serum and Lung Tissue from Normotensive and Spontaneously Hypertensive Rats

Angiotensin-converting enzyme (ACE) activity in serum and lung tissue from both normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) was determined at six different circadian times. In WKY rats serum ACE varied significantly within 24 h, mainly due to reduced enzyme activity at 12:00 h. In SHR the 24-h profile of serum ACE did not exhibit time-dependent differences. Mean serum ACE activity over 24 h was significantly higher in WKY than in SHR. In lung tissue ACE activity did not depend on the circadian time in either strain. Mean enzyme activity in lung tissue was not different between WKY and SHR. We conclude that circadian changes in the activity of serum and tissue ACE are unlikely to play an important role in the regulation of the circadian blood pressure profile in both normotensive and spontaneously hypertensive rats.     

Potato tuber-inducing activities of salicylic acid and related compounds

Salicylic acid (SA) induced potato tuberization in vitro at concentrations greater than 10^–5 M. A comparison of the tuber-inducing activities of various related compounds suggested that derivatives of benzoic acid with a free carboxyl group and a substituent at the C-2 position of the benzene ring have this activity. Although SA had the strongest activity among the compounds tested, the activity was about one thousandth of that of natural jasmonic acid (1R,2S-jasmonic acid) in terms of the threshold concentration for activity. Spraying SA to leaves of plants grown under tuber-noninducing conditions (long days) induced tuberization. However, the natural occurrence of SA was not detected in the leaves of potato plants that had been grown under tuber-inducing conditions (short days) and had begun to form tubers. The results seem to exclude the possibility of the involvement of SA in the natural tuberization of potato plants.     

In vitro evaluation of photodynamic activity of methylene blue against Trichophyton verrucosum azole-susceptible and -resistant strains

The intense search for the “Holy Grail” of antifungal therapy can be observed today. The searches are not limited only to discovery of potential antifungal drugs, but also new therapeutic strategies involving the use of chemosensitizers to achieve synergistic effect or physicochemical factors inducing stress conditions in fungal cells. In this study was examined in vitro effectiveness of photodynamic antifungal strategy with methylene blue using a light beam with a wavelength equal to 635 nm toward the Trichophyton verrucosum susceptible and itraconazole- and/or fluconazole-resistant strains. Methylene blue used at concentration equal to 5 μg/mL and in the presence of 40 J/cm² of light energy showed fungicidal effect toward the susceptible strains. However, for azole-resistant isolates, only the energy dose equal to 60 J/cm² at 5 μg/mL of methylene blue allowed to kill the pathogen. This study confirms that methylene blue induced by red light has a definite inhibitory effect on zoophilic dermatophytes.