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U Wormser

Publications and source records attributed to U Wormser.

At least 19 recordsLinked to original sources
PubMed1998

Skin surface proteolytic activity. Partial characterization and identification.

Skin surface proteolytic activity in the living animal was determined by a sensitive, non-invasive methodology developed in our laboratory. A non-leaky well was constructed on the shaved back of an anesthetized guinea pig. The well contained the reaction mixture including the substrate 125I-S-carboxymethylated insulin B-chain (ICMI). The proteolytic activity was shown to be time-dependent. The activity was strongly inhibited by pepstatin A, indicating the involvement of aspartic proteinase(s) such as cathepsin D and/or E. Pretreatment of the skin with propylene glycol blocked the proteolytic activity. The present study demonstrates the presence of proteolytic activity located on skin surface using a unique, non-invasive method for in situ proteinase determination in the living animal.

Animals↗
PubMed1997

Protective effect of povidone-iodine ointment against skin lesions induced by sulphur and nitrogen mustards and by non-mustard vesicants.

Mustard gas (sulphur mustard, SM) is a powerful vesicant employed as a chemical weapon. The present study demonstrates the effect of povidone iodine (PI) ointment against skin toxicity caused by SM. Gross and histopathological examinations showed that application of PI up to 20 min following exposure to the vesicant resulted in marked skin protection. The shorter the interval between exposure and treatment the better was the protection achieved. PI was also effective against other mustards such as carboxybutyl chloroethyl sulphide (CBCS) and mechlorethamine. The fact that PI protected the skin against agents which cannot be oxidized such as iodoacetic acid, divinylsulphone and cantharidine showed that the antidotal effect of PI was unrelated to oxidation of the nitrogen and sulphur atoms of the mustards. PI ointment is proposed as an efficient protective agent against skin toxicity caused by mustards and other alkylators.

Animals↗
PubMed1997

Noninvasive procedure for in situ determination of skin surface aspartic proteinase activity in animals; implications for human skin.

The present study demonstrated a noninvasive procedure for in situ determination of stratum corneum aspartic proteinase in the living animal. A non-leaky well, containing [125I]S-carboxymethylated insulin B-chain (ICMI) as a substrate, was constructed on the shaved back of anesthetized guinea pigs and rats. The enzymatic activity was determined by measuring the radiolabeled trichloroacetic acid soluble material. We demonstrated pepstatin-sensitive proteinase activity bound to the skin surface indicating the involvement of aspartic proteinase(s) such as cathepsin D and/or E. Aged rats had about six fold lower activity than young animals. The proteinase activity was inhibited by the alkylating agent mechlorethamine and by the cosmetic propylene glycol. A similar procedure was carried out with intact human skin pieces obtained during plastic surgery. The activity was inhibited by antihuman cathepsin D antibodies. Cathepsin D was immunohistochemically localized in the corneal and granular layers of the epidermis. Skin surface aspartic proteinase/cathepsin D activity may serve as a marker for skin aging or for certain skin disorders leading to a new approach to their medical treatments.

Aging↗
PubMed1996

In vivo and in vitro toxicity of newly synthesized monofunctional sulfur mustard derivatives.

The toxicity of two new monofunctional sulfur mustard derivatives was tested. The compound (4-carboxybutyl 2-chloroethyl sulfide, CBCS; 10-carboxydecyl 2-chloroethyl sulfide, CDCS) possess the 2-chloroethyl sulfide moiety present in mustard gas. Exposure of guinea pig skin to CBCS resulted in a dose-related ulcerative effect. CDCS exhibited similar pathological effects. Dimethylsulfoxide (DMSO) exacerbated CBCS toxicity. Regeneration and healing were prominent six days after application. Concentration-related effects were found in in vitro systems, using human SH-SY5Y neuroblastoma cells for acute toxicity and Y79 retinoblastoma cells for colony forming assay. CBCS or derivatives may serve as models compounds for investigating the mechanism of action of alkylating agents.

Administration, Topical↗
PubMed1992

Possible pitfalls in rat extended dermal toxicity testing: an hepatic-ocular syndrome.

During a sub-chronic dermal toxicity study, hepatic and ocular toxicity were detected unrelated to the compound being tested. The changes in the liver were characterized by hepatic centrilobular degeneration and fibrosis due to chronic passive congestion. Clinical chemistry results confirmed the active hepatic damage and cholestasis. The ocular changes were limited to the retina where diffuse retinal atrophy was seen originating adjacent to the optic nerve and progressing centrifugally. It is suggested that as a consequence of the bandaging technique, a state of passive congestion and cholestasis resulted. The decrease in flow of bile acids to the intestine caused disturbances in vitamin E absorption. The deficiency of the antioxidant vitamin was responsible for the retinal changes seen.

Animals↗
PubMed1991

Protective effect of O-phenanthroline against mechlorethamine toxicity in the rat liver slice system and in the guinea pig skin.

The effect of O-phenanthroline (OP) on mechlorethamine hydrochloride (HN2) toxicity was studied in in vitro and in vivo experiments. Incubation of HN2 with the in vitro rat liver slice system resulted in leakage of alanine aminotransferase (ALT) in a time-dependent manner. Exposure of the slices to HN2 for 4 h caused 79.2% ALT leakage. In the presence of OP enzyme leakage was reduced to 28.7%. OP-induced protection was shown to be dose dependent. Other metal chelators such as dithiothreitol (DTT) and EDTA (ethylenediaminetetraacetic acid) had a weak effect on HN2 cytotoxicity. The protective activity of OP was also demonstrated in in vivo skin toxicity studies in the guinea pig. The ulcerative effect of topically applied HN2 was inhibited by OP even when applied 10 min following the alkylator. Histology of NH2-treated skin showed epidermal ulceration associated with a covering layer of encrusted exudate. However, only a slight diffuse acanthosis of the epidermal layer was observed when OP was applied for 10 min after the vesicant. It is suggested that OP may be used for the prevention of tissue damage caused by antineoplastic treatment with nitrogen mustard. It might also be employed in military medicine as an antidote to the chemical weapon sulfur mustard.

Animals↗
PubMed1991

Toxicology of mustard gas.

The devastating effects of mustard gas were first observed in World War I. The advent of the Gulf War fueled renewed fears of further use of toxic gases in battle, with the possible exposure of large civilian populations--while understanding of the mechanism of action of the alkylating sulfur mustards was still quite restricted. In this article Uri Wormser discusses the structure--activity studies that are available, and the limited pharmacological measures that can be taken to protect against mustard gas attack. In addition to systemically administered sulfhydryl agents, new percutaneous preparations are being developed in the author's laboratory which offer better protection than is possible with simple adsorbant powders.

Animals↗
PubMed1991

Hepatic and renal metallothionein induction in the rat and mouse after treatment with furosemide.

Induction of hepatic and and renal metallothionein by furosemide was studied in the rat and mouse. Treatment of mice with 200 and 300 mg/kg furosemide elevated hepatic metallothionein by 117% and 366%, while renal metallothionein was induced by 29% and 380%, respectively. In the rat the drug was less potent i.e. liver metallothionein was increased by 167% and 217% following injection of 300 and 400 mg/kg furosemide, respectively, whereas kidney was not significantly changed by this treatment. The mouse hepatic and renal metallothionein was identified as zinc-containing thionein by Sephadex G-75 gel filtration (Ve/Vo = 2.0). In both species maximal induction was observed 24 hours post exposure. However, the mouse hepatic and renal metallothionein content declined after additional 24 hours whereas the rat metalloprotein was not reduced even after 72 hours of treatment. It is suggested that alterations in metal homeostasis may be responsible for hepatic and renal metallothionein induction caused by furosemide.

Animals↗
PubMed1990

Proteolytic resistance and biological activity of N-methylated analogs of [pGlu6] substance P6-11.

Five synthetic N-methylated analogs (II-V) of the C-terminal hexapeptide analog of substance P (SP), [pGlu6]SP6-11 (I) were evaluated for their metabolic stability and in vitro spasmogenic activity. The metabolic resistance of the analogs was tested by two SP degrading systems with different specificities, namely, the rat parotid and the hypothalamic slice systems. Their biological activity was assessed in the isolated guinea pig ileum. The analog [pGlu6, N-Me Phe7, N-Me Gly9]SP6-11 (III), had relative potency of 65% in the spasmogenic assay as compared to the parent compound. It was found to be more stable than the parent peptide in the hypothalamus, whereas in the parotid system it was susceptible as the parent peptide. However, the analog [pGlu6, N-Me Leu10]SP6-11 (II) (46% relative potency in the spasmogenic assay) was more stable than the parent peptide in the parotid system but did not show any improved stability in the hypothalamus. Identification of degradation products of the [pGlu6, N-Me Leu10]SP6-11 reflected the differences in the specificities of the two preparations. A significant drop in potency (7%) was observed for [pGlu, N-Me Phe7]SP6-11 (IV). This analog was more stable in the hypothalamic system than in the parotid. Introduction of a double methylation, [pGlu6, N-Me Leu10] SP6-11, contributed toward the stabilization in both degrading systems. Its relative spasmogenic activity was comparable to that of analog IV. In light of the above mentioned findings the implications of the N-methylated analogs with respect to putative CNS activity are discussed.

Animals↗
PubMed1988

Increased levels of hepatic metallothionein in rat and mouse after injection of acetaminophen.

Induction of hepatic metallothionein (MT) by acetaminophen was characterized in the rat and mouse. Treatment of rats with the hepatotoxin resulted in increase of liver MT in a dose-dependent manner. MT concentration was elevated by 41%, 140% and 260% following acetaminophen injection at doses of 250, 500 and 1000 mg/kg, respectively. The cadmium-binding protein was identified as MT by Sephadex G-75 gel filtration (Ve/Vo = 2.1). In the mouse the hepatotoxin was more potent i.e. maximal effect (increase of 230%) was achieved at the lowest applied dose (250 mg/kg). In both species maximal induction was observed 24 h post exposure and thereafter the hepatic MT content declined, indicating a relatively short half-life of the protein. The elevation of the intracellular concentration of a sulfhydryl-rich protein such as MT may serve as self protecting mechanism of the hepatocyte against highly reactive metabolites of toxic substances.

Acetaminophen↗
PubMed1988

Metallothionein induction by cadmium and zinc in rat secretory organs.

Metallothionein (MT) levels were determined in four secretory organs of the rat following administration of zinc (Zn) and cadmium (Cd). The concentrations of MT in the lacrimal, parotid and adrenal glands of untreated rats were in the range of 2.2-4.9 micrograms/g wet weight tissue while in the pancreas it was shown to be 15.2 micrograms/g. Injection of zinc at total doses of 16, 32 and 80 mg/kg resulted in a 1.8-, 3.2- and 5.9-fold increase in lacrimal MT content, respectively, while a 10.2- and 13.1-fold elevation was observed following treatment with 4 and 8 mg/kg of Cd, respectively. Similar findings were found in the adrenal gland. The parotid MT was elevated 5.9 and 17 times following Zn treatment at doses of 16 and 80 mg/kg respectively, whereas 4 mg/kg of Cd increased MT 14.4 times in this gland. Pancreatic MT was elevated by 39- and 40-fold after injection of Zn at doses of 16 and 32 mg/kg respectively, whereas 4 and 8 mg/kg of Cd caused a 9.8- and 17.9-fold induction, respectively. These results may indicate that secretory organs participate in metabolism of heavy metals in the mammalian body.

Adrenal Glands↗
PubMed1988

Effect of age on cadmium-induced metallothionein synthesis in the rat.

Cadmium-induced metallothionein (MT) synthesis was investigated in male rats of three ages, 3, 12 and 24 months. Physiological levels of MT in kidney, liver and lung measured simultaneously in untreated animals were found to be within the same range in all three age groups. Following 3-day treatment with CdCl2 equivalent to 1 mg/kg/day Cd, renal MT increased 10-15-fold in all animals. However, hepatic MT became elevated to 36 times the original value in the youngest (3-month-old) rats and 90 and 74 times, respectively, in the 12- and 24-month-old groups. Lung MT, which responded rather poorly to the cadmium inducer, increased 2-fold in the young group, but about 10 and 8 times, respectively, in the two older groups. High mortality of 75% occurred in the aged (24-month-old) group following cadmium administration, indicating age to be an important sensitizing factor in the toxic hazard of heavy metal exposure. The possible role in this connection of MT is discussed.

Aging↗