in accordance with the present invention , there are provided methods for the in vivo reduction of nitric oxide levels in a subject . invention methods comprise : administering to a subject an effective amount of at least one dithiocarbamate - containing nitric oxide scavenger . dithiocarbamate - containing nitric oxide scavengers contemplated for use in the practice of the present invention include any physiologically compatible derivative of the dithiocarbamate moiety ( i . e ., ( r ) 2 n -- c ( s )-- sh ). such compounds can be described with reference to the following generic structure : each of r 1 and r 2 is independently selected from a c 1 up to c 18 alkyl , substituted alkyl , cycloalkyl , substituted cycloalkyl , heterocyclic , substituted heterocyclic , alkenyl , substituted alkenyl , alkynyl , substituted alkynyl , aryl , substituted aryl , heteroaryl , substituted heteroaryl , alkylaryl , substituted alkylaryl , arylalkyl , substituted arylalkyl , arylalkenyl , substituted arylalkenyl , arylalkynyl , substituted arylalkynyl , aroyl , substituted aroyl , acyl , substituted acyl or r 1 and r 2 can cooperate to form a 5 -, 6 - or 7 - membered ring including n , r 1 and r 2 , m is a monovalent cation when x is 1 , or m is a physiologically compatible divalent or trivalent transition metal cation when x is 2 . presently preferred compounds having the above - described generic structure are those wherein : each of r 1 and r 2 = a c 1 up to c 12 alkyl , substituted alkyl , alkenyl , substituted alkenyl , alkynyl or substituted alkynyl , wherein the substituents are selected from carboxyl , -- c ( o ) h , oxyacyl , phenol , phenoxy , pyridinyl , pyrrolidinyl , amino , amido , hydroxy , nitro or sulfuryl , and especially preferred compounds having the above - described generic structure are those wherein : r 1 = a c 2 up to c 8 alkyl or substituted alkyl , wherein the substituents are selected from carboxyl , acetyl , pyridinyl , pyrrolidinyl , amino , amido , hydroxy or nitro , r 2 is selected from a c 1 up to c 6 alkyl or substituted alkyl , or r 2 can cooperate with r 1 to form a 5 -, 6 - or 7 - membered ring including n , r 2 and r 1 , and the presently most preferred compounds having the above - described generic structure are those wherein : r 1 = a c 2 up to c 8 alkyl or substituted alkyl , wherein the substituents are selected from carboxyl , acetyl , amido or hydroxy , r 2 = a c 1 up to c 4 alkyl or substituted alkyl , and when r 1 and r 2 cooperate to form a 5 -, 6 - or 7 - membered ring , the combination of r 1 and r 2 can be a variety of saturated or unsaturated 4 , 5 or 6 atom bridging species selected from alkenylene or -- o --, -- s --, -- c ( o )-- and / or -- n ( r )-- containing alkylene moieties , wherein r is hydrogen or a lower alkyl moiety . monovalent cations contemplated for incorporation into the above compounds include h + , na + , nh 4 + , tetraalkyl ammonium , and the like . physiologically compatible divalent or trivalent transition metal cations contemplated for incorporation into the above compounds include charged forms of iron , cobalt , copper , manganese , or the like ( e . g ., fe + 2 , fe + 3 , co + 2 , co + 3 , cu + 2 , mn + 2 or mn + 3 ). in accordance with the present invention , the ratio of dithiocarbamate - species to counter - ion m can vary widely . thus , dithiocarbamate - containing nitric oxide scavenger can be administered without any added metallic counter - ion ( i . e ., m = h + , or a transition metal cation to dithiocarbamate - species ratio of zero ), with ratios of transition metal cation to dithiocarbamate - species up to about 1 : 2 ( i . e ., a 2 : 1 dithiocarbamate : transition metal cation complex ) being suitable . as employed herein , &# 34 ; substituted alkyl &# 34 ; comprises alkyl groups further bearing one or more substituents selected from hydroxy , alkoxy ( of a lower alkyl group ), mercapto ( of a lower alkyl group ), cycloalkyl , substituted cycloalkyl , heterocyclic , substituted heterocyclic , aryl , substituted aryl , heteroaryl , substituted heteroaryl , aryloxy , substituted aryloxy , halogen , trifluoromethyl , cyano , nitro , nitrone , amino , amido , -- c ( o ) h , acyl , oxyacyl , carboxyl , carbamate , sulfonyl , sulfonamide , sulfuryl , and the like . as employed herein , &# 34 ; cycloalkyl &# 34 ; refers to cyclic ring - containing groups containing in the range of about 3 up to 8 carbon atoms , and &# 34 ; substituted cycloalkyl &# 34 ; refers to cycloalkyl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; alkenyl &# 34 ; refers to straight or branched chain hydrocarbyl groups having at least one carbon - carbon double bond , and having in the range of about 2 up to 12 carbon atoms , and &# 34 ; substituted alkenyl &# 34 ; refers to alkenyl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; alkynyl &# 34 ; refers to straight or branched chain hydrocarbyl groups having at least one carbon - carbon triple bond , and having in the range of about 2 up to 12 carbon atoms , and &# 34 ; substituted alkynyl &# 34 ; refers to alkynyl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; aryl &# 34 ; refers to aromatic groups having in the range of 6 up to 14 carbon atoms and &# 34 ; substituted aryl &# 34 ; refers to aryl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; alkylaryl &# 34 ;, refers to alkyl - substituted aryl groups and &# 34 ; substituted alkylaryl &# 34 ; refers to alkylaryl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; arylalkyl &# 34 ; refers to aryl - substituted alkyl groups and &# 34 ; substituted arylalkyl &# 34 ;, refers to arylalkyl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; arylalkenyl &# 34 ; refers to aryl - substituted alkenyl groups and &# 34 ; substituted arylalkenyl &# 34 ; refers to arylalkenyl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; arylalkynyl &# 34 ; refers to aryl - substituted alkynyl groups and &# 34 ; substituted arylalkynyl &# 34 ; refers to arylalkynyl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; aroyl &# 34 ; refers to aryl - carbonyl species such as benzoyl and &# 34 ; substituted aroyl &# 34 ; refers to aroyl groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; heterocyclic &# 34 ; refers to cyclic ( i . e ., ring - containing ) groups containing one or more heteroatoms ( e . g ., n , o , s , or the like ) as part of the ring structure , and having in the range of 3 up to 14 carbon atoms and &# 34 ; substituted heterocyclic &# 34 ; refers to heterocyclic groups further bearing one or more substituents as set forth above . as employed herein , &# 34 ; halogen &# 34 ; refers to fluoride , chloride , bromide or iodide atoms . in accordance with another embodiment of the present invention , there are provided methods for treating nitric oxide overproduction in a subject . invention methods comprise : administering to a subject an effective amount of at least one dithiocarbamate - containing nitric oxide scavenger . nitric oxide overproduction is associated with a wide range of disease states and / or indications , such as , for example , septic shock , ischemia , administration of cytokines , overexpression of cytokines , ulcers , inflammatory bowel disease ( e . g ., ulcerative colitis or crohn &# 39 ; s disease ), diabetes , arthritis , asthma , alzheimer &# 39 ; s disease , parkinson &# 39 ; s disease , multiple sclerosis , cirrhosis , allograft rejection , encephalomyelitis , meningitis , pancreatitis , peritonitis , vasculitis , lymphocytic choriomeningitis , glomerulonephritis , uveitis , ileitis , liver inflammation , renal inflammation , hemorrhagic shock , anaphylactic shock , burn , infection ( including bacterial ( e . g ., e . coli infection ), viral ( e . g ., hiv ), fungal ( e . g ., candidiosis and histoplasmosis ) and parasitic ( e . g ., leishmaniasis and schistosomiasis ) infections ), hemodialysis , chronic fatigue syndrome , stroke , cancers ( e . g ., breast , melanoma , carcinoma , and the like ), cardiopulmonary bypass , ischemic / reperfusion injury , and the like . with particular reference to cytokine therapy , the invention method will find widespread use because cytokine therapy ( with consequent induction of nitric oxide overproduction ) is commonly used in the treatment of cancer and aids patients . systemic hypotension due to the induction of . no overproduction is a dose - limiting side effect of cytokine therapy . thus , a large patient population exists which will benefit from the invention method . presently preferred indications for treatment in accordance with the present invention include septic shock , ischemia , administration of il - 1 , administration of il - 2 , administration of il - 6 , administration of il - 12 , administration of tumor necrosis factor , administration of interferon - gamma , ulcers , ulcerative colitis , diabetes , arthritis , asthma , alzheimer &# 39 ; s disease , parkinson &# 39 ; s disease , multiple sclerosis , cirrhosis or allograft rejection . especially preferred indications for treatment in accordance with the present invention include nitric oxide overproduction associated with septic shock and nitric oxide overproduction associated with cytokine therapy . in accordance with a particular aspect of the present invention , the dithiocarbamate - containing nitric oxide scavenger is administered in combination with a cytokine ( e . g ., il - 1 , il - 2 , il - 6 , il - 12 , tnf or interferon - γ ), an antibiotic ( e . g ., gentamicin , tobramycin , amikacin , piperacillin , clindamycin , cefoxitin or vancomycin , or mixtures thereof ), a vasoactive agent ( e . g ., a catecholamine , noradrenaline , dopamine or dobutamine ), or mixtures thereof . in this way , the detrimental side effects of many of the above - noted pharmaceutical agents ( e . g ., systemic hypotension ) can be prevented or reduced by the dithiocarbamate - containing nitric oxide scavenger . thus , a patient being treated with any of the above - described agents could be monitored for evidence of nitric oxide overproduction ( e . g ., blood pressure drop ). at the first evidence of such overproduction , co - administration of a suitable dose of the above - described dithiocarbamate - containing nitric oxide scavenger could be initiated , thereby alleviating ( or dramatically reducing ) the side - effects of the primary therapy . those of skill in the art recognize that the dithiocarbamate - containing nitric oxide scavengers described herein can be delivered in a variety of ways , such as , for example , orally , intravenously , subcutaneously , parenterally , rectally , by inhalation , and the like . since individual subjects may present a wide variation in severity of symptoms and each drug has its unique therapeutic characteristics , the precise mode of administration and dosage employed for each subject is left to the discretion of the practitioner . in general , the dosage of dithiocarbamate - containing nitric oxide scavenger employed in the practice of the present invention falls in the range of about 0 . 01 mmoles / kg body weight of the subject / hour up to about 0 . 5 mmoles / kg / hr . in accordance with still another embodiment of the present invention , there are provided physiologically active composition ( s ) comprising a compound having the structure i or the structure ii , as described hereinafter , in a suitable vehicle rendering said compound amenable to oral delivery , transdermal delivery , intravenous delivery , intramuscular delivery , topical delivery , nasal delivery , and the like . as noted above , compounds of structure i ( i . e ., dithiocarbamate - species free of transition metal cations ) can be employed directly in the practice of the present invention , or pre - formed dithiocarbamate - transition metal chelates ( i . e ., compounds of structure ii ) having varying ratios of transition metal to dithiocarbamate - species can be employed in the invention methods . depending on the mode of delivery employed , the dithiocarbamate - containing nitric oxide scavenger can be delivered in a variety of pharmaceutically acceptable forms . for example , the scavenger can be delivered in the form of a solid , solution , emulsion , dispersion , micelle , liposome , and the like . pharmaceutical compositions of the present invention can be used in the form of a solid , a solution , an emulsion , a dispersion , a micelle , a liposome , and the like , wherein the resulting composition contains one or more of the compounds of the present invention , as an active ingredient , in admixture with an organic or inorganic carrier or excipient suitable for enteral or parenteral applications . the active ingredient may be compounded , for example , with the usual non - toxic , pharmaceutically acceptable carriers for tablets , pellets , capsules , suppositories , solutions , emulsions , suspensions , and any other form suitable for use . the carriers which can be used include glucose , lactose , gum acacia , gelatin , mannitol , starch paste , magnesium trisilicate , talc , corn starch , keratin , colloidal silica , potato starch , urea , medium chain length triglycerides , dextrans , and other carriers suitable for use in manufacturing preparations , in solid , semisolid , or liquid form . in addition auxiliary , stabilizing , thickening and coloring agents and perfumes may be used . the active compound ( i . e ., compounds of structure i or structure ii as described herein ) is included in the pharmaceutical composition in an amount sufficient to produce the desired effect upon the process or condition of diseases . pharmaceutical compositions containing the active ingredient may be in a form suitable for oral use , for example , as tablets , troches , lozenges , aqueous or oily suspensions , dispersible powders or granules , emulsions , hard or soft capsules , or syrups or elixirs . compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of a sweetening agent such as sucrose , lactose , or saccharin , flavoring agents such as peppermint , oil of wintergreen or cherry , coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations . tablets containing the active ingredient in admixture with non - toxic pharmaceutically acceptable excipients may also be manufactured by known methods . the excipients used may be , for example , ( 1 ) inert diluents such as calcium carbonate , lactose , calcium phosphate or sodium phosphate ; ( 2 ) granulating and disintegrating agents such as corn starch , potato starch or alginic acid ; ( 3 ) binding agents such as gum tragacanth , corn starch , gelatin or acacia , and ( 4 ) lubricating agents such as magnesium stearate , stearic acid or talc . the tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period . for example , a time delay material such as glyceryl monostearate or glyceryl distearate may be employed . they may also be coated by the techniques described in the u . s . pat . nos . 4 , 256 , 108 ; 4 , 160 , 452 ; and 4 , 265 , 874 , to form osmotic therapeutic tablets for controlled release . in some cases , formulations for oral use may be in the form of hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent , for example , calcium carbonate , calcium phosphate or kaolin . they may also be in the form of soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium , for example , peanut oil , liquid paraffin , or olive oil . the pharmaceutical compositions may be in the form of a sterile injectable suspension . this suspension may be formulated according to known methods using suitable dispersing or wetting agents and suspending agents . the sterile injectable preparation may also be a sterile injectable solution or suspension in a non - toxic parenterally - acceptable diluent or solvent , for example , as a solution in 1 , 3 - butanediol . sterile , fixed oils are conventionally employed as a solvent or suspending medium . for this purpose any bland fixed oil may be employed including synthetic mono - or diglycerides , fatty acids ( including oleic acid ), naturally occurring vegetable oils like sesame oil , coconut oil , peanut oil , cottonseed oil , etc ., or synthetic fatty vehicles like ethyl oleate or the like . buffers , preservatives , antioxidants , and the like can be incorporated as required . compounds contemplated for use in the practice of the present invention may also be administered in the form of suppositories for rectal administration of the drug . these compositions may be prepared by mixing the drug with a suitable non - irritating excipient , such as cocoa butter , synthetic glyceride esters of polyethylene glycols , which are solid at ordinary temperatures , but liquify and / or dissolve in the rectal cavity to release the drug . since individual subjects may present a wide variation in severity of symptoms and each drug has its unique therapeutic characteristics , it is up to the practitioner to determine a subject &# 39 ; s response to treatment and vary the dosages accordingly . typical daily doses , in general , lie within the range of from about 10 μg up to about 100 mg per kg body weight , and , preferably within the range of from 50 μg to 10 mg per kg body weight and can be administered up to four times daily . the daily iv dose lies within the range of from about 1 μg to about 100 mg per kg body weight , and , preferably , within the range of from 10 μg to 10 mg per kg body weight . in accordance with yet another embodiment of the present invention , there are provided compounds having the structure i : provided , however , that the following compounds are excluded from the definition of formula i , i . e ., when r 1 is ethyl , r 2 is not ethyl ; or when r 1 is ch 2 ( choh ) 4 ch 2 oh , r 2 is not methyl , isoamyl , benzyl , 4 - methylbenzyl or p - isopropylbenzyl ; or when r 1 is ch 2 co 2 --, r 2 is not ch 2 co 2 --; or when r 1 is c0 2 -, r 2 is not ch 3 ; or when r 1 is ch 2 ch 2 -- oh , r 2 is not ch 2 ch 2 -- oh ; or when r 1 and r 2 combined , together with the carbamate nitrogen , form a pyrrolidinyl - 2 - carboxylate . in accordance with still another embodiment of the present invention , there are provided compounds having the structure ii : m is a physiologically compatible divalent or trivalent transition metal cation , provided , however , that the following compounds are excluded from the definition of formula ii , i . e ., when r 1 is ethyl , r 2 is not ethyl ; or when r 1 is ch 2 ( choh ) 4 ch 2 oh , r 2 is not methyl , isoamyl , benzyl , 4 - methylbenzyl or p - isopropylbenzyl ; or when r 1 is ch 2 co 2 --, r 2 is not ch 2 co 2 --; or when r 1 is co 2 --, r 2 is not ch 3 ; or when r 1 is ch 2 ch 2 -- oh , r 2 is not ch 2 ch 2 -- oh ; or when r 1 and r 2 combined , together with the carbamate nitrogen , form a pyrrolidinyl - 2 - carboxylate . also contemplated are compositions representing a combination of compounds of structure i and compounds of structure ii , i . e ., dithiocarbamate species wherein the ratio of m + 1 : dithiocarbamate - species is less than 1 : 1 and the ratio of m + 2 ,+ 3 : dithiocarbamate - species is less than 1 : 2 . a presently preferred composition is one wherein the ratio of m + 2 ,+ 3 : dithiocarbamate - species is about 1 : 5 ( i . e ., about 40 % of the dithiocarbamate - species are incorporated into a dithiocarbamate : transition metal cation complex , while about 60 % of the dithiocarbamate - species exist in monovalent form ). r 1 = a c 1 up to c 12 alkyl , substituted alkyl , alkenyl , substituted alkenyl , alkynyl or substituted alkynyl , wherein the substituents are selected from carboxyl , -- c ( o ) h , oxyacyl , phenol , phenoxy , pyridinyl , pyrrolidinyl , amino , amido , hydroxy , nitro or sulfuryl , r 2 = a c 1 up to c 4 alkyl or substituted alkyl , and r 1 = a c 2 up to c 8 alkyl or substituted alkyl , wherein the substituents are selected from carboxyl , acetyl , pyridinyl , pyrrolidinyl , amino , amido , hydroxy or nitro , the presently most preferred compounds having the structure ii are those wherein : r 1 = a c 2 up to c 8 alkyl or substituted alkyl , wherein the substituents are selected from carboxyl , acetyl , amido or hydroxy , the invention will now be described in greater detail by reference to the following non - limiting examples . icr mice ( female , 20 - 30 g ) were supplied by harlan sprague - dawley ( indianapolis , ind .). dexamethasone , lipopolysaccharide ( lps ; e . coli 026 : b6 ) and acetylcholine chloride were obtained from sigma ( st . louis , mo .). 15 n 2 - guanido - l - arginine ( 15 n - arginine ) was purchased from cambridge isotope laboratories ( woburn , mass .). n g - monomethyl - l - arginine ( nmma ) was obtained from calbiochem ( san diego , calif .). methoxyflurane was obtained from pitman - moore ( mundelein , ill .). pure . no gas was purchased from matheson ( joliet , ill .) and pure argon gas was obtained from airco ( murray hill , n . j .). saturated . no solution in water was prepared by following the method of kelm and schrader , supra . the concentration of the saturated . no solution is 2 . 0 mm , as verified by an iso - no meter from world precision instruments ( sarasota , fla .). no 2 - was measured by a colorimetric assay ( green et al ., anal . biochem . 126 : 131 - 138 ( 1982 )). no 3 -- was first converted to no 2 - by e . coli nitrate reductase ( bartholomew , b ., fd . chem . toxic . 22 : 541 - 543 ( 1984 )) and measured as described above . n - methyl - d - glucamine and carbon disulfide were obtained from aldrich ( milwaukee , wis .). n - methyl - d - glucamine dithiocarbamate ( mgd ) was synthesized by following the method of shinobu et al . ( acta pharmacol . toxicol . 54 : 189 - 194 ( 1984 )). a . in vivo measurement of ( mgd ) 2 / fe - no ! levels in the circulation of the lps - treated mice . noninvasive in vivo epr spectra were recorded with an epr spectrometer equipped with an s - band microwave bridge and a low - frequency loop - gap resonator with a 4 - mm loop with a length of 1 cm , operating at 3 . 5 ghz ( froncisz and hyde , j . magn . reson . 47 : 515 - 521 ( 1982 )). instrument settings include 100 - g field scan , 30 - s scan time , 0 . 1 - s time constant , 2 . 5 - g modulation amplitude , 100 - khz modulation frequency and 25 - mw microwave power . the measured unloaded q of the empty resonator was 3000 and the loaded q was 400 ( with the presence of the mouse tail ). other instrument settings and experimental conditions have been described previously ( komarov et al ., supra and lai and komarov , supra ). for measurement of 15 no production , at 6 h after i . v . injection of lps ( 6 mg / mouse ) via the lateral tail vein , the mice were anesthetized with methoxyflurane prior to subcutaneous injections of 15 n - arginine ( 5 or 10 mg per mouse ) in saline , and of 0 . 4 ml of the ( mgd ) 2 / fe ! complex ( 326 mg / kg of mgd and 34 mg / kg of feso 4 ) in water . injections of ( mgd ) 2 / fe ! complex at levels up to 1 % body weight did not affect the survival of the mice ( lai and komarov , supra ). immediately after injection , the mouse housed in a plexiglass restraining tube was transferred to the s - band epr spectrometer and the tail of the mouse was immobilized by taping down with a thin and narrow plexiglass stick and then placed inside the resonator ; no anesthetic agent was used . the in vivo epr signal was recorded at 2 h after the injection of the ( mgd ) 2 / fe ! complex ( lai and komarov , supra ). for inhibition experiments , at 6 h after lps treatment , mice were injected intraperitoneally with an aliquot of 50 mg / kg n - monomethyl - l - arginine ( nmma ) in saline . nmma is an inhibitor of both constitutive and inducible synthase activities ( aisaka et al ., supra and rees et al ., supra ). in other experiments , at 1 . 5 h prior to lps challenge , mice were injected intravenously with 3 mg / kg dexamethasone in saline . dexamethasone is an inhibitor of inducible . no synthase , but not constitutive . no synthase ( rees et al ., biochem . biophys . res . commun . 173 : 541 - 547 ( 1990 )). the in vivo epr signal was also recorded at 2 h after the injection of ( mgd ) 2 / fe ! complex ( lai and komarov , supra ). b . ex vivo measurements of ( mgd ) 2 / fe - no ! levels in the urine of normal mice . normal mice housed in a restraining tube were injected subcutaneously with 0 . 4 ml of the ( mgd ) 2 / fe ! complex ( 326 mg / kg of mgd and 34 mg / kg of feso 4 ). after 2 h , the animals were sacrificed and the urine samples were collected from the urinary bladder . the urine sample , which was dark brown ( characteristic of the presence of ( mgd ) 2 / fe ! complex ), was transferred to a quartz flat cell for epr measurement . the spectra were recorded at 22 ° c . with an x - band epr spectrometer , operating at 9 . 5 ghz . instrument settings include 100 - g field scan , 4 - min scan time , 0 . 5 - s time constant , 2 . 5 - g modulation amplitude , 100 - khz modulation frequency and 100 - mw microwave power . the concentrations of the ( mgd ) 2 / fe - no ! complex in the urine samples were calculated by comparing the signal intensities obtained from the samples to the signal intensity of a standard solution containing 0 . 1 mm of the ( mgd ) 2 / fe - no ! complex . for inhibition experiments , mice were injected intraperitoneally with 50 mg / kg nmma in saline immediately after the injection of the ( mgd ) 2 / fe ! complex . in other experiments , mice were injected intravenously with 3 mg / kg dexamethasone in saline about 1 . 5 h before the injection of the ( mgd ) 2 / fe ! complex . for measurement of 15 no production in normal mice , mice were injected subcutaneously with 15 n - arginine ( 5 or 10 mg / mouse ) in saline immediately before the injection of the ( mgd ) 2 / fe ! complex . acetylcholine chloride ( sigma ) in saline was freshly prepared prior to subcutaneous injection at a dose of 67 mg / kg . c . ex vivo measurement of ( mgd ) 2 / fe - no ! levels in the urine of lps - treated mice . at 0 , 2 , 4 , 6 or 8 h after lps treatment ( 6 mg / mouse ; at least three animals in each group ), the mice housed in a restraining tube were anesthetized with methoxyflurane prior to subcutaneous injection with 0 . 4 ml of the ( mgd ) 2 / fe ! complex ( 326 mg / kg of mgd and 34 mg / kg of feso 4 ). after 2 h , the mouse was sacrificed and the urine sample was collected from the urinary bladder , and immediately transferred to a quartz flat cell for x - band epr measurement as described above in example 2b . inhibition experiments with nmma or dexamethasone were performed as described above in example 2a , except that the mice were treated with lps prior to following the protocols for . no inhibition experiments . the procedures for s - band epr measurement of wet tissues and blood samples were as described previously ( lai and komarov , supra ). at 2 h after subcutaneous injection of an aliquot ( 0 . 4 ml ) of the ( mgd ) 2 / fe ! complex ( 326 mg / kg of mgd and 34 mg / kg of feso 4 ) into normal mice ( a ) ( and also in the presence of nmma ( 50 mg / kg ) ( b ), or of dexamethasone ( 3 mg / kg ) ( c )), the animals were sacrificed and the urine samples collected and transferred to a quartz flat cell for x - band ( 9 . 5 ghz ) epr measurement at 22 ° c . the spectrum of the urine samples was found to be composed of two components , a three - line spectrum ( α n = 12 . 5 g and g iso = 2 . 04 ) characteristic of the ( mgd ) 2 / fe - no ! complex , and a strong broad signal ( see fig1 a ). the strong broad signal is part of the epr spectrum of the ( mgd ) 2 / cu ! complex present in the urine , resulting from the chelation of urinary copper by the excreted mgd molecule . the concentration of the ( mgd ) 2 / fe - no ! complex detected in the urine sample of normal mice is estimated to be 1 . 3 μm ( see table 1 ). table 1______________________________________quantitation of the amounts of ( mgd ). sub . 2 / fe -- no ! present in mouse urine under various conditionsconditions ( mgd ). sub . 2 / fe -- no !, μm . sup . a______________________________________controls 1 . 3 ± 0 . 2 ( 8 ) . sup . b + nmma ( 50 mg / kg ) 0 . 4 ± 0 . 3 ( 8 ) *+ acetylcholine ( 67 mg / kg ) 3 . 9 ± 0 . 8 ( 3 ) *+ dexamethasone ( 3 mg / kg ) 1 . 4 ± 0 . 3 ( 7 ) ______________________________________ . sup . a the amounts of the ( mgd ). sub . 2 / fe -- no ! complex in mouse urine were calculated by comparing the epr signal intensities of mouse urine with the signal intensity of a standard solution containing known concentration of ( mgd ). sub . 2 / fe -- no !. . sup . b the data presented are mean ± s . e . ( number of mice ). * p & lt ; 0 . 05 compared with controls . simultaneous injection of ( mgd ) 2 / fe ! and nmma markedly reduced the ( mgd ) 2 / fe - no ! signal in the urine samples , see fig1 b and table 1 . on the other hand , as noted in fig1 c and table 1 , injection of ( mgd ) 2 / fe ! into mice pretreated with dexamethasone produced negligible effects on the ( mgd ) 2 / fe - no ! signal . these results suggest that the no detected in normal mouse urine in the form of the ( mgd ) 2 / fe - no ! complex was produced by constitutive no synthase , but not by inducible . no synthase . to further verify this suggestion , the effect of acetylcholine , a vasodilatory agent which is known to effect the basal . no level , but not the inducible . no level ( aisaka et al ., biochem . biophys . res . commun . 163 : 710 - 717 ( 1989 ); whittle et al ., br . j . pharmacol . 98 : 646 - 652 ( 1989 ); and vicaut et al ., j . appl . physiol . 77 : 536 - 533 ( 1994 )), was tested on the urinary ( mgd ) 2 / fe - no ! level of normal mice . injection of acetylcholine was found to produce a 3 - fold increase in urinary ( mgd ) 2 / fe - no ! levels ( see table 1 ). this observation represents the first direct in vivo evidence to confirm that the endothelium - derived relaxation factor released by acetylcholine ( the furchgott phenomenon ) is indeed nitric oxide . the question is raised whether the . no detected in normal mouse urine ( example 3 ) and the . no trapped by the ( mgd ) 2 / fe ! complex ( table 1 ) is a result of the injection of the ( mgd ) 2 / fe ! complex . in other words , does the injection of the complex alone enhance the . no production in vivo ? in the previous experiments , it has been shown that the intravenous injection of the ( mgd ) 2 / fe ! complex did not affect the mean arterial pressure of mice ( komarov , et al . supra ), suggesting that the complex by itself does not seem to affect the in vivo . no production . it is well established in the art that l - arginine is converted into . no and citrulline by . no synthase enzymes ( ignarro , l . j ., supra ; moncada , s ., supra ; and lowenstein and snyder , supra ). to determine the origin of . no detected in normal mouse urine , 15 n - arginine ( 10 mg / mouse ) and ( mgd ) 2 / fe ! were injected simultaneously , and the epr signal in the resulting urine sample was measured , as described above . thus , mice were injected with 0 . 4 ml of the ( mgd ) 2 / fe ! complex ( 326 mg / kg of mgd and 34 mg / kg of feso 4 ) with ( a ) 10 mg 15 n - arginine or ( b ) 5 mg 15 n - arginine . the animals were sacrificed at 2 h after injection , and the urine samples were transferred to a quartz flat cell for epr measurement at 22 ° c . it was reasoned that if the . no detected in normal mouse urine comes from the arginine - no synthase pathway , upon injection of 15 n - arginine , one should expect to detect the 15 no in the form of the ( mgd ) 2 / fe - 15 no ! complex in the urine . this indeed was the case as seen by epr , in which the two - line spectrum of the ( mgd ) 2 / fe - i 5 no ! complex was detected in the urine , along with a weak three - line spectrum of the ( mgd ) 2 / fe - 14 no ! complex ( fig2 a , the solid lines ); the 14 no was generated by the same enzymatic pathway , except utilizing endogenous 14 n - arginine as a substrate . this suggests that subcutaneously injected 15 n - arginine competes effectively with endogenous 14 n - arginine as a substrate for . no synthases . when 15 n - arginine was omitted from the injection solution , the typical three - line spectrum of the ( mgd ) 2 / fe - 14 no ! complex became more visible ( see fig2 a , dotted lines ). on the other hand , when the amount of 15 n - arginine injected ( 5 mg / mouse ) was reduced by one - half , the signal intensity of the ( mgd ) 2 / fe - 15 no ! complex decreased compared to that of the ( mgd ) 2 / fe - 14 no ! complex ( see fig2 b ). therefore , it can be concluded that the ( mgd ) 2 / fe ! complex injected subcutaneously into normal mice interacts with the . no produced in tissues through the arginine - constitutive . no synthase pathway to form the ( mgd ) 2 / fe - no ! complex , which is eventually concentrated in the urine and excreted . detection of the ( mgd ) 2 / fe - no ! complex in the blood circulation of lps - treated mice it has previously been shown that upon bolus infusion of lps ( 6 mg / mouse ), mice are in septic - shock like conditions within 6 h , as indicated by a gradual fall in mean arterial pressure from 121 ± 3 mm hg to 85 ± 7 mm hg ( lai and komarov , supra ). in addition , it has been shown that at 6 h after lps treatment , the in vivo three - line spectrum of the ( mgd ) 2 / fe - no ! complex ( wherein ( mgd ) 2 / fe ! is injected subcutaneously 2 h before epr measurement ) is observed in the circulation of the mouse tail , as detected by s - band epr spectroscopy ( lai and komarov , supra ). to further ascertain the chemical nature of . no detected in lps - treated mice , 15 n - arginine ( 10 mg / kg ) was injected , together with 0 . 4 ml of the ( mgd ) 2 / fe ! spin - trapping reagent ( 326 mg / kg of mgd and 34 mg / kg of feso 4 ), into lps - treated mice and measured in vivo by s - band epr spectrum . the in vivo s - band epr spectra were recorded 2 h after administration of the ( mgd ) 2 / fe ! complex . albeit weak , the in vivo two - line spectrum of the ( mgd ) 2 / fe 15 - no ! complex in the circulation of the mouse tail was clearly visible ( fig3 a , the solid lines ), further confirming that the detected . no in the form of the ( mgd ) 2 / fe - no ! complex in lps - treated mice was produced via the arginine - no synthase pathway . the three - line spectrum typical of the ( mgd ) 2 / fe - 14 no ! complex was obtained when 15 n - arginine was omitted ( fig3 a , the dotted lines ). the mice treated with 15 n - arginine were sacrificed , and the whole blood obtained was transferred for x - band epr measurement at 22 ° c . the epr signal of the whole blood obtained from 15n - arginine treated mice ( fig3 b ) is identical to that of the solid lines of fig3 a . this suggests that the epr signal in fig3 a or fig3 b is attributed to the ( mgd ) 2 / fe - no ! complex circulating in the blood , rather than trapped in the tail muscle at or near the site of the injection . the s - band epr signal of the ( mgd ) 2 / fe - 15 no ! complex was also detected in various isolated tissues obtained from lps - treated mice injected with the ( mgd ) 2 / fe ! complex and 1 n - arginine ( fig4 ). thus , the two - line spectrum characteristic of ( mgd ) 2 / fe - 15 no !, superimposed with the three - line spectrum characteristic of ( mgd ) 2 / fe - 14 no !, were observed in the liver and kidneys ( see fig4 a and 4b , respectively ). again , the spectrum characteristic of the ( mgd ) 2 / fe - 14 no ! complex was detected in the mouse liver when 15 n - arginine was omitted from the injection fluid ( see fig4 a , the dotted lines ). detection of the ( mgd ) 2 / fe - no ! complex in the urine of lps - treated mice the effects of nmma on ex vivo 9 . 5 - ghz epr spectra of the ( mgd ) 2 / fe - no ! complex in the urine of the lps - treated mice were determined . thus , at 6 h after lps treatment , mice were injected with the ( mgd ) 2 / fe ! complex , with and without i . p . injection of nmma ( 50 mg / kg ). the mice were sacrificed at 2 h after injection of the ( mgd ) 2 / fe ! complex . the urine samples were collected and the epr measurement was carried out at 22 ° c . a strong three - line spectrum characteristic of the ( mgd ) 2 / fe - no ! complex was detected in the urine sample obtained from the lps - treated mouse injected with the ( mgd ) 2 / fe ! complex ( see fig5 a ). the concentration of the complex is estimated to be 35 . 1 μm at 8 h after lps challenge ; the ( mgd ) 2 / fe ! complex was injected at 6 h after lps . injection of nmma markedly reduces the signal intensity ( fig5 b ) as well as the amounts of the ( mgd ) 2 / fe - no ! complex ( table 2 ), which is consistent with the notion that the . no trapped by the ( mgd ) 2 / fe ! complex injected in the lps - treated mice is produced mainly by inducible . no synthase . thus , inducible . no synthase activities in living animals may be reduced by treatment with . no trapping agents as described herein . furthermore , simultaneous injection of 15 n - arginine ( 10 mg / mouse ) and the ( mgd ) 2 / fe ! complex into the lps - treated mice gave rise to a composite epr spectrum , consisting of a two - line spectrum of the ( mgd ) 2 / fe - 15 no ! complex ( closed circles ), and a three - line spectrum of the ( mgd ) 2 / fe - 14 no ! complex ( open circles ) as shown in fig6 a ( the solid lines ). the pure three - line spectrum of the ( mgd ) 2 / fe - 14 no ! complex as depicted by the dotted lines in fig6 a was obtained when 15 n - arginine was omitted from the injection solution . in addition , when 15 n - arginine was administered at a level of 5 mg / mouse , the signal intensity of the ( mgd ) 2 / fe - 15 no ! complex was reduced compared to that of the ( mgd ) 2 / fe - 14 no ! complex ( fig6 b ). the results clearly confirm that the . no detected in the lps - treated mouse urine was overproduced via the arginine - no synthase pathway . in summary , the isotopic tracer experiments using 15 n - arginine have unambiguously demonstrated that the no trapped by the ( mgd ) 2 / fe ! complex either in normal or the lps - treated mice is produced via arginine - no pathway ( fig2 , 4 and 6 ). the authenticity of . no produced in vivo which is trapped by the ( mgd ) 2 / fe ! complex in our experimental systems is therefore firmly established . the time - dependent increase in ( mgd ) 2 / fe - no ! levels detected in urine samples after lps administration is shown in table 2 . table 2______________________________________time - dependent changes in the amounts of ( mgd ). sub . 2 / fe -- no ! present in the lps - treated mouse urineconditions ( mgd ). sub . 2 / fe -- no !, μm . sup . a______________________________________lps - treated . sup . b0 h 1 . 4 ± 0 . 4 ( 3 ) . sup . c2 h 7 . 3 ± 2 . 2 ( 3 ) * 4 h 18 . 2 ± 4 . 8 ( 4 ) * 6 h 17 . 1 ± 4 . 8 ( 4 ) * 8 h 35 . 1 ± 5 . 7 ( 3 ) * lps - treated ( after 6 h ) . sup . d + nmma ( 50 mg / kg ) 3 . 6 ± 0 . 9 ( 4 ) †+ nmma ( 100 mg / kg ) 3 . 8 ± 2 . 3 ( 3 ) † ______________________________________ . sup . a the amounts of ( mgd ). sub . 2 / fe -- no ! in mouse urine were determine as described in table 1 . . sup . b at different times points after lps challenge as indicated , the mice were injected subcutaneously with ( mgd ). sub . 2 / fe !, and were sacrificed 2 h later to collect urine for epr measurement . . sup . c the data presented are mean ± s . e . ( number of mice ). . sup . d various amounts on nmma were injected intraperitoneally at 6 h after lps challenge just prior to injection of ( mgd ). sub . 2 / fe !. urine was collected 2 h later . * p & lt ; 0 . 05 compared with controls ( see table 1 ). † p & lt ; 0 . 05 compared with the lpstreated group at 6 h . in vivo reduction of no levels by ( mgd ) 2 / fe ! complex in lps - treated mice the time - dependent increase in plasma nitrate levels in lps - treated mice was determined as previously described ( see komarov and lai , supra ). the results are summarized in table 3 . table 3______________________________________effects of lps and ( mgd ). sub . 2 / fe ! on total nitrate / nitrite levels in mouse plasmaconditions nitrate / nitrite , μm . sup . a______________________________________controls 73 ± 7 ( 10 ) . sup . dlps - treated . sup . b2 h 103 ± 10 ( 6 ) * 4 h 291 ± 38 ( 6 ) * 6 h 506 ± 75 ( 4 ) * 8 h 638 ± 29 ( 8 ) * lps + mgd ). sub . 2 / fe ! complex . sup . c8 h 336 ± 46 ( 3 ) *† ______________________________________ . sup . a the nitrate / nitrite determination in the mouse plasma was performe as previously described ( see komarov and lai , supra ). . sup . b the mice were sacrificed at different time points as indicated after intravenous injection of lps . . sup . c at 6 h after lps challenge the mice were injected subcutaneously with ( mgd ). sub . 2 / fe ! and were sacrificed 2 h later . . sup . d the data presented are mean ± s . e . ( number of mice ). * p & lt ; 0 . 05 compared with controls † p & lt ; 0 . 05 compared with the lpstreated group at 8 h . nitrate levels are seen to increase with time after lps challenge . injection of the . no trapping agent , ( mgd ) 2 / fe !, reduced the nitrate level in the plasma by about one - half , a result suggesting that the trapping of . no by ( mgd ) 2 / fe ! in the lps - treated mice prevents it from interaction with hemoglobin in the red blood cells , thereby reducing nitrate levels in the plasma . these results demonstrate that the administration of a dithiocarbamate - containing nitric oxide scavenger , such as the ( mgd ) 2 / fe ! complex , is effective to reduce in vivo . no levels in lps - treated mice . although the route by which the subcutaneously injected spin - trapping reagent enters the tissues before its excretion into the urine is not yet known , it can be speculated that upon subcutaneous injection , the ( mgd ) 2 / fe ! complex diffuses across the capillary bed , where it interacts with . no produced by . no synthases to form the ( mgd ) 2 / fe - no ! complex . the latter complex then enters the blood circulation and is eventually excreted and concentrated in the urine , thereby reducing in vivo . no levels . the isolated urine containing the ( mgd ) 2 / fe - no ! complex was found to be stable at 4 ° c . for several hours . when the ( mgd ) 2 / fe ! complex was injected intravenously into normal or lps - treated mice , the epr signal of the ( mgd ) 2 / fe - no ! complex was also detected in the urine . this suggests that regardless of the route of administration employed , dithiocarbamate - containing nitric oxide scavengers , such as the ( mgd ) 2 / fe ! complex , are capable of interacting with the . no produced in vivo to form a dithiocarbamate - fe - no complex , which reduces in vivo . no levels . as shown in example 7 , subcutaneous administration of the ( mgd ) 2 / fe ! complex reduced the in vivo . no levels in lps - treated mice . since excessive . no production is known to induce systemic hypotension , injections of the ( mgd ) 2 / fe ! complex that reduce in vivo . no levels should also restore blood pressure in hypotensive animals induced by lps treatment . to test this idea , experiments were carried out to determine the effects of administration of the ( mgd ) 2 / fe ! complex on the blood pressure of the hypotensive rats induced by lps challenge . thus , male wistar rats ( 230 - 300 g ) fasted overnight were anesthetized with thiobutabarbital ( inactin , 100 mg / kg , i . p .). a catheter was implanted in the femoral vein for drug infusions . the femoral artery was cannulated for continuous blood pressure measurement . rats were injected with an i . v . bolus dose of lps ( s . typhosa endotoxin , 4 mg / kg ). two hours after lps challenge , rats were then subjected to one of the following treatments : ( a ) control , saline infusion -- 1 . 0 ml saline i . v . injection followed by 1 . 0 ml / hr of saline infusion for 1 . 5 hours , ( b ) ( mgd ) 2 / fe ! ( at a ratio of 2 - to - 0 . 4 )- 0 . 1 mmole / kg i . v . bolus injection followed by 0 . 1 mmole / kg infusion for 1 . 5 hours , ( c ) ( mgd ) 2 / fe ! ( at a ratio of 2 - to - 0 . 2 )- 0 . 1 mmole / kg i . v . bolus injection followed by 0 . 1 mmole / kg infusion for 1 . 5 hours , and ( d ) ( mgd ) 2 / fe ! ( at a ratio of 2 - to - o )- 0 . 1 mmole / kg i . v . bolus injection followed by 0 . 1 mmole / kg infusion for 1 . 5 hours . the results of mean arterial pressure ( map ) measurement are summarized in table 4 . table 4______________________________________effects of various ratios of ( mgd ). sub . 2 / fe ! treatment on themean arterial pressure ( map in mmhg ) in thelipopolysaccharide ( lps )- induced shocked rats . 2 hrs 1 . 5 hrs baseline . sup . 2 after lps afterconditions . sup . 1 ( mean ± sem ) treatment treatment______________________________________a ) control 96 ± 2 77 ± 2 78 ± 4saline ( n = 16 ) . sup . 3b ) ( mgd ). sub . 2 / fe ! 95 ± 3 75 ± 2 96 ± 3 ( 2 / 0 . 4 ) . sup . 4 ( n = 16 ) c ) ( mgd ). sub . 2 / fe ! 98 ± 3 73 ± 4 87 ± 4 ( 2 / 0 . 2 ) ( n = 6 ) d ) mgd ( 2 / 0 ) 102 ± 5 73 ± 2 94 ± 6 ( n = 6 ) ______________________________________ . sup . 1 experimental conditions were as described in the text . . sup . 2 the values of map prior to lps treatment . . sup . 3 n , the number of animals in each group . . sup . 4 ( mgd ). sub . 2 / fe ! ( 2 / 0 . 4 ) is defined as the ratio of ( mgd ). sub . 2 / fe ! to be 2to - 0 . 4 . the map of anesthetized rats was in the range of 96 to 102 mmhg . two hours after lps treatment , the map decreased to between 73 and 77 mmhg , which is indicative of the onset of systemic hypotension , caused by abnormally elevated levels of nitric oxide . while the 1 . 5 hr saline infusion did not change the map , infusions of ( mgd ) 2 / fe ! complex at various ratios , ranging from 2 - to - 0 . 4 ( mgd to fe ) to 2 - to - 0 ( mgd to fe ), restored the blood pressure to 87 - 96 mmhg ( table 4 ). these results suggest that the i . v . infusion of mgd either with or without added iron ( fe ) can restore normal blood pressure in hypotensive rats induced by lps challenge ( table 4 ). since mgd does not bind . no , it is speculated that the restoration of the map by mgd infusion may at least in part be attributed to the mgd chelation of cellular iron released by excess . no production , which is known to attack cellular iron - containing proteins and result in cellular iron loss during sepsis or septic shock . this example shows that mgd , either with or without added iron , is effective for the treatment of systemic hypotension , a condition which is associated with many inflammatory and / or infectious diseases . while the invention has been described in detail with reference to certain preferred embodiments thereof , it will be understood that modifications and variations are within the spirit and scope of that which is described and claimed .
the present invention employs a scavenging approach whereby overproduced nitric oxide is bound in vivo to a suitable nitric oxide scavenger . the resulting complex renders the nitric oxide harmless , and is eventually excreted in the urine of the host . further in accordance with the present invention , there are provided compositions and formulations useful for carrying out the above - described methods . an exemplary nitric oxide scavenger contemplated for use in the practice of the present invention is a dithiocarbamate - ferrous iron complex . this complex binds to . no , forming a stable , water - soluble dithiocarbamate - iron - no complex having a characteristic three - line spectrum which can readily be detected at ambient temperatures by electron paramagnetic resonance spectroscopy . the present invention relates to methods for reducing in vivo levels of . no as a means of treating subjects afflicted with inflammatory and / or infectious disease . dithiocarbamate - containing nitric oxide scavengers are administered to a host in need of such treatment ; these scavengers interact with in vivo produced . no , forming a stable dithiocarbamate - metal - no complex . the no - containing complex is then filtered through the kidneys , concentrated in the urine , and eventually excreted by the subject , thereby reducing in vivo . no levels .