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Metrizamide was compared with metrizoate in a double blind investigation. Cardioangiography was performed in 30 infants and children below 2 years of age with congenital heart disease. Adverse reactions were few and unimportant. Changes in ECG, ventricular pressure and heart rate during and after the contrast injections were recorded. The side effects were slight in both groups. Metrizamide caused less changes than metrizoate at a statistically significant level.

The combined effects of an iodine contrast medium and X-rays on the number of colony forming units (CFUs) in mice bone marrow were examined in vitro and in vivo. No changes were observed in the number of CFUs per 105 nucleated bone marrow cells, when the contrast medium alone was added to bone marrow cell suspensions at concentration of 0.5 and 5.0%. X-irradiation of the suspensions above a dose of 50 R reduced the number of CFUs per 105 cells. The irradiation of the suspensions in the presence of the contrast medium produced further decrease in the number of CFUs per 105 cells, depending on the concentration of the medium used. No enhancement of the X-ray effect was observed when mice were injected with the contrast medium at a dosage 10 times higher than that used in X-ray diagnosis in man and irradiated immediately. Thus, the iodine contrast medium sensitized hematopoietic stem cells to X-rays in vitro but did not in vivo.

The properties of Nycodenz, a new nonionic iodinated density gradient medium, are described. This compound shares a number of characteristics with its related compound metrizamide. However, the stabler, more inert nature of Nycodenz endows it with a number of favorable properties as a gradient medium.

Selective left vertebral angiography was carried out in 21 rabbits comparing the toxic effects of meglumine iothalamate (Conray meglumine), meglumine metrizoate (Isopaque Cerebral) and metrizamide (Amipaque). The iodine concentration for all 3 media was 280 mg/ml. General convulsions were seen in many of the animals with all 3 media. The convulsions occurred at higher doses and were milder with metrizamide than with the 2 other contrast agents. Bradycardia was also seen with all 3 media and there was no statistical significant difference between them in this respect. The mortality was approximately 50% with both meglumine iothalamate and meglumine metrizoate, while no animals died following angiography with metrizamide.

The sites of degradation of human low density lipoprotein (LDL), are analyzed using the novel labelling compound O-(4-diazo-3-[125I]iodobenzoyl)sucrose (D125IBS). The decay from rat serum of D125IBS-labelled LDL is identical to the serum decay of conventionally iodinated (ICI method) LDL. The radioactivity derived from D125IBS-labelled LDL accumulates predominantly in the liver after intravenous injection and the hepatic radioactivity remains associated with the lysosomal compartment for an extended period of time, when compared to the radioactivity derived from conventionally iodinated LDL. It is concluded that the D125IBS labelling procedure is an interesting new tool to study the sites of catabolism of serum lipoproteins.

The haemodynamic and cardiac side effects of the new non-ionic contrast medium, iohexol, were investigated anaesthetized rats and isolated perfused rabbit hearts. Iohexol, caused a positive inotropic response in both models, elevated coronary flow and in high doses had an inhibitory influence on the cardiac conducting system. From a comparison with Amipaque and Urografin 76 it was concluded that with respect to cardiac side effects iohexol can be ranked between these media.

The non-ionic contrast medium metrizamide was compared to the sodium salt of diatrizoate to investigate the potential usefulness of metrizamide in clinical urography when ureteric stasis is applied. After intravenous injection of the contrast media to rabbits at dose level 175 mg I/kg, the kidneys were subjected to temporary bilateral ureteric stasis. Urine was collected through ureteric catheters and analyzed for its concentration of iodine, sodium and potassium. After metrizamide injection the urine iodine concentration was twice as high as after sodium diatrizoate injection. This difference between one non-ionic and one ionic contrast medium was larger than what has been reported earlier during free flow of urine at the same dose. Furthermore, during the periods of ureteric stasis metrizamide was excreted faster than diatrizoate. When diatrizoate was given as its sodium salt, the sodium given was excreted at about the same rate as the diatrizoate given.

✓ Seventeen ventriculograms with the non-ionic water-soluble contrast medium, metrizamide, were performed in 15 patients, with negligible adverse effects. Visualization of the ventricular system was good in most of the patients. A combined technique, using both metrizamide and gas, increased the diagnostic value of the procedure in some cases.

The myocardial toxicity of iodamide (Jodomiron 380) in selective coronary angiography was compared with that of metrizoate (Isopaque coronar). Electrocardiographic changes, systolic blood pressure and heart rate were registered and compared in a total of 106 injections. Both contrast media produced transient changes in ST-segment and T-wave, reduced the heart rate and systolic blood pressure. Differences noted were: a more marked hypotensive effect after injection of Jodomiron into the left coronary artery, and a higher frequency of moderate electrocardio graphic changes at injection of Isopaque into the right coronary artery. Because of the small number of registrations, however, these differences were not conclusive. The diagnostic quality of examination with both contrast media was excellent.

Intravenous cholangiograms were performed on 100 unselected nonicteric patients using methylglucamine ioglycamide (Biligram). Fifty patients received 10.5 g of contrast medium and 50 received 5.25 g of medium. The contrast medium was injected evenly over five minutes. Side effects were recorded in only 13% of patients and all were mild. Radiographs were taken 10, 30, 60, 90, and 120 minutes after injection and were assessed without the authors being aware of the dose of contrast medium injected. Better statistically significant results were obtained using the higher dose. In patients in whom the gallbladder is present, films taken at 60 minutes and 90 minutes after injection give the maximum available information in 97% of cases. If the gallbladder has not become opacified by 60 minutes, cystic duct obstruction is indicated. In postcholecystectomy patients, films at 30 minutes and 60 minutes after injection give the maximum available information in 95% of cases.

Arachnoiditis, a common finding in patients who have had previous myelograms or spinal surgery, can cause pain, paresis, and can slow elimination of contrast medium from the subarachnoid space. The role of contrast media in producing arachnoiditis has not been well defined but can be studied in a primate model. This study compared incidence of arachnoiditis in monkeys after myelograms using two nonionic contrast media, iohexol and metrizamide. Conditions were chosen to produce the greatest possible effect of contrast medium on the arachnoid. Animals were sacrificed 12 weeks after the myelogram and the dural sac was removed for examination by light microscope. Under adverse conditions, high doses and high concentrations of iohexol produced little arachnoiditis, while metrizamide produced mild to moderate arachnoiditis. Iohexol was shown to have a greater margin of safety then metrizamide, which is considered an important clinical advantage.

A double-blind comparison of two intravenous cholangiocholecystographic agents of similar molecular structure, meglumine iodoxamate and meglumine iodipamide, was carried out in 90 patients. Each produced a comparably high percentage of satisfactory examinations. A similar pattern of excretion speed and intensity was noted for each, though meglumine iodoxamate appeared to be slightly more effective in patients with elevated serum bilirubin. Less evidence of hepatic toxicity and fewer and less serious adverse side effects were observed in patients given the newer agent, meglumine iodoxamate.

Ioversol 320, a new nonionic iodinated contrast medium, was injected intravenously into 24 healthy male volunteers using saline as a control. Physical examination, vital signs, electrocardiogram, biochemical and hematological data were recorded before and at intervals after injection. No significant changes were observed. Seventeen volunteers reported no side effects; six volunteers had mild transitory symptoms considered to be related to the contrast medium. The authors conclude that broader clinical trials can be safely conducted to determine safety and tolerability of ioversol.

The effect of ligand binding upon the buoyant density of DNA in Nycodenz gradients has been studied using DNAs of differing base compositions. The effect of both intercalating ligands (ethidium bromide and proflavin) and non-intercalating ligands (distamycin A, DAPI and netropsin) has been studied. The binding of intercalating ligands to DNA has essentially no effect on the buoyant density of DNA in Nycodenz gradients. The non-intercalating ligands were found to increase the buoyant density of DNA in a base specific manner. The increase in buoyant density can be interpreted in terms of disruption of the hydration shell of the DNA molecule caused by the binding of the ligand along the minor groove of the DNA helix.

The isoantigenicity of rabbit germ cells and their extracts was studied by using a Western blot enzyme immunobinding procedure after systemic and local intrauterine immunization. In the deoxycholate (DOC) sperm extract, the antisperm isoantiserum (ASA) recognized proteins of 100, 96, 92, 82, 53, 47, 43, and 29 kD, and the antitestis isoantiserum (ATA) recognized proteins of 100, 96, 92, 82, 43, and 29 kD. In the lithium diiodosalicylate (LIS) sperm extract, ASA reacted with four antigen bands of 92, 30, 14, and 6 kD, and ATA reacted with proteins of 94, 92, 91, 23, 17, 7, and 6 kD. In the reduced sodium dodecyl sulfate (SDS) sperm extract, ASA recognized proteins of 95, 76, 51, 41, 33, 30, 28, 26, and 22 kD; ATA showed a reaction only with proteins of 100, 98, and 95 kD, and anti-LIS/sperm isoantiserum (ALA) recognized three proteins of 98, 81, and 65 kD. The IgA of the immune uterine fluid (IUF) from the LIS/sperm-immunized rabbits recognized a 14-kD antigen in the DOC conceptus extract, a 51-kD antigen in the DOC testis extract, and 53-, 49-, 31-, and 28-kD proteins in the reduced SDS-sperm pellet extract. The IgA of the IUF from the NP-40/pellet-immunized rabbits showed two proteins of about 100 kD, plus ones of 56, 36, 31, 29, 19, 17, and 14 kD in the DOC conceptus extract; proteins of 92, 70, 51, 29, and 14 kD in the DOC testis extract; and of 61, 57, 53, 49, 35, 31, and 28 kD in the reduced SDS-sperm pellet extract.

Pharmacokinetics and excretion of iohexol, a new nonionic water-soluble contrast medium, were determined after lumbar myelography. Peak plasma concentrations were obtained 2 to 6 hours after injection and ranged from 29 to 177 microgram/ml. Terminal elimination half-life was 4.0 hours, and over 90% of the dose was recovered in the urine within 24 hours. In one patient with a large lumbar cauda equina tumor, absorption and excretion were delayed; but eventually 99% was recovered indicating a large capacity for reabsorption via the lumbar subarachnoid space. One mild headache of 5 minutes' duration was reported in a 73-year-old woman. No significant changes in vital signs, neurologic examinations, or serum chemistries were observed.

Ioglucomide, a new iodinated nonionic contrast medium directed primarily toward myelographic use, was subjected to an extensive toxicological examination in animals. In the majority of studies, ioglucomide was compared directly with metrizamide. In some respects, including freedom from production of arachnoiditis, ioglucomide and metrizamide were comparable. However, acute toxicity after intravenous injection or instillation into cerebrospinal fluid was significantly less for ioglucomide. Also, in contrast to metrizamide, ioglucomide produced no evidence of any type of convulsive activity after subarachnoid administration. The improved safety of ioglucomide could not be related to osmolality; therefore, the importance of osmolality for nonionic myelographic agent safety is questioned.

The authors evaluated double-blind comparative and open-label clinical trials in 1,186 patients who received ioversol to evaluate the safety and efficacy of ioversol, a new nonionic low-osmolality contrast medium, at iodine concentrations of 32%, 24%, and 16%. The results indicate that ioversol was well tolerated in all patients and showed fewer adverse effects than conventional ionic agents. The diagnostic efficacy of ioversol was comparable to both conventional and other nonionic agents with respect to diagnostic quality. However, the improved patient tolerance may contribute to higher quality radiographs. The effects on renal function were monitored at 24, 48, 72, and 96 hours and did not reveal any clinically or statistically significant changes.

Several compounds have been described which elute fibronectin from a gelatin-Sepharose affinity support. In the present study, it has been found that the potent chaotrophic agent, lithium di-iodosalicylic acid, is 20-fold more effective in eluting fibronectin from collagen than any other presently described fibronectin elution agent. Lithium di-iodosalicylic acid and certain other fibronectin elution agents have been characterized in regard to several parameters involved in the elution of fibronectin from collagen and plastic substrata. By assaying for retention of the cell adhesive activity of fibronectin, it has been demonstrated that 8 M urea + 0.1 M citric acid, pH 4.7, is the most effective condition for preservation of biological activity following elution of fibronectin from the gelatin-Sepharose affinity support.

Injections of non-ionic monomeric (metrizamide, C29 and iohexol) and monoacidic dimeric (ioxaglate) contrast media into the femoral artery of dogs caused significantly less increase in the rate of femoral blood flow than the more hypertonic ionic monomeric compound metrizoate at equivalent iodine concentrations. The effect of metrizoate was similar to that of equiosmolal solutions of sodium chloride. Sodium chloride in concentrations equiosmolal with the non-ionic monomers and monoacidic dimer caused less changes in blood flow than these contrast media, but the changes in blood were equal to those of isotonic sodium chloride.

The influence of a phenobarbital pretreatment on the distribution and biliary excretion of Ioglycamide was studied in 6 experiments in the anaesthetized minipig. The phenobarbital pretreatment led to a significant increase of the biliary transportmaximum and the biliary concentration of Ioglycamide. A detailed analysis suggests a phenobarbital induced stimulation of the hepatocellular excretion. The applicability of a pretreatment with phenobarbital in order to improve the opacification of the biliary system during x-ray-examinations with Ioglycamide is discussed.

A preliminary study of 18 patients following a single bolus intravenous injection of 10 to 30 cc. of meglumine iodoxamate (Cholovue), a new contrast medium for cholangio-cholecystography, showed no significant adverse clinical or laboratory effects with 10 and 20 cc., and only transient, minor changes with 30 cc. Early and persistent visualization of the subsegmental and major bile ducts and the gallbladder was obtained. Good to excellent opacification was obtained in all cases with doses ranging between 0.11 cc./kg. (19.7 mg. iodine) to 0.59 cc./kg. (108 mg. iodine). Meglumine iodoxamate appears to be a highly effective agent for cholangio-cholecystography.

A new method is reported for the synthesis of N-succinimidyl p-([125/127I]iodobenzoate (NS-p-IB) from N-succinimidyl p-(tri-n-butylstannyl)benzoate via an iodination-destannylation reaction. The tin precursor was obtained in 70% overall yield from p-bromobenzoyl chloride after a four-step synthesis. The radiochemical yield of NS-p-[125I]IB was 75%. Conjugation of NS-p-[125I]IB to rabbit IgG or bovine serum albumin gave yields of 52 and 60% respectively. In vitro the radiolabeled proteins in serum at 37 degrees C showed less than 1% deiodination by 24 h. In vivo the stability of mouse IgG (MIgG) labeled with NS-p-[125I]IB was superior to MIgG radioiodinated in the presence of chloramine-T.

A double-blind clinical study of 50 children undergoing cardiac catheterization was performed to evaluate Hexabrix and Renografin-76 in pediatric angiocardiography. The contrast agents were randomly assigned. There was no statistical difference in image quality between Hexabrix and Renografin-76 at similar iodine concentrations and no subjective difference in radio-opacity or overall angiographic quality. Little or no discomfort was experienced with Hexabrix whereas with Renografin-76, there was more pain. Hexabrix may be advantageous for cardiovascular diagnosis since motion artifact due to pain can adversely affect angiographic detail.

Ioversol, the new nonionic, low-osmolality contrast agent, has been well characterized chemically and in terms of basic toxicity testing. Ioversol has a formula similar to that of other nonionic agents, and has been used in a variety of clinical studies. These have been reviewed in detail in other papers. This article reviews the worldwide experience to date with the intra-arterial use of this contrast agent. Ioversol has been given to more than 500 patients for studies including intra-arterial digital subtraction angiography, and cerebral, visceral, peripheral, and cardiac angiography. In 23 carefully monitored studies, ioversol was shown to be safe and diagnostically efficacious, as compared with several high- and low-osmolality agents. To date, there have been no deaths or other severe reactions with this new nonionic formulation. Ioversol is likely to provide a useful addition to the current formulary of low-osmolality agents.

Fab fragments of rabbit anti-p-azobenzoate antibody have been crystallized. Washed, redissolved crystalline materials has the same binding constant toward p-iodobenzoate as the intact antibody, 8 X 10(4) M-1.

Hexabrix, a low-osmolality radiographic contrast agent consisting of the meglumine and solium salt of ioxaglic acid (600 mOsm/kg), was evaluated in 50 children undergoing cardiac catheterization in a randomized double-blind manner. In comparison with a conventional radiographic contrast agent (Renografin-76), Hexabrix produced a marked redution in the pain or discomfort after the injection. Neither agent produced any significant change in pulse or respiratory rates or blood pressure. Changes in left and right ventricular pressures were small and comparable for both groups. Significant dysrhythmias were not noted. There was no evidence of deterioration in renal or hepatic function in either group. Serum LDH and CPK increased comparably with both contrast agents but without any definite evidence of myocardial injury. Postinjection increases in serum osmolality were slightly, but not significantly, higher with Renografin. In the first few hours following the procedure there was an increase in circulating segmented neutrophils and a reciprocal decrease in lymphocytes; this was transient and gone by 24 hours. Radiographic image quality was judged good or excellent in almost all cases. Hexabrix is a contrast agent that is significantly better tolerated than conventional agents and is associated with no greater incidented than conventional agents and is associated with no greater incidence of side-effects while producing radiographic images of equivalent quality.

The purpose of this study was to analyze arthrographic imaging of the structures of the shoulder joint when using either sodium meglumine metrizoate or iopamidol as a contrast medium. Two hundred and ten patients underwent single-contrast shoulder arthrography. In patients with a full-thickness tear of the rotator cuff, both contrast agents reliably revealed this lesion. However, in patients with a full-thickness rotator cuff tear, the biceps tendon could be demonstrated more readily with iopamidol, which is a non-ionic contrast medium.

The x-ray attenuation of the renal cortex of dogs, as determined by computed tomographic (CT) scanning, was measured over a three-day period after an intravenous bolus of 600 mg I/kg of iotrol or iopamidol. A slightly higher density observed 24 hours after injection of iotrol was not considered significant, and was not considered sufficient to warrant clinical application of iotrol for specific, prolonged renal enhancement.

The possible beneficial effects of added calcium ions to contrast media to diminish myocardial toxicity was evaluated in 93 cardiac catheterizations with cardioangiography, performed in 50 children and adolescents. Two contrast media with equal iodine content (370 mg/ml) and similar physical properties were used: Isopawue-370, containing 0.34 mg calcium/ml, and Renografin-76, not containing calcium. It is concluded that addition of calcium to contrast media for cardioangiography in children and adolescents does not alter their myocardial, fluid or electrolyte effects when injected selectively into the cardiac chambers or great vessels.

Sixty patients from the University of British Columbia, Vancouver General Hospital, and University of Alberta Hospitals Edmonton participated in an open-labelled clinical study on the safety, tolerability and efficacy of ioxaglic acid (Hexabrix) in cerebral angiography. Only 4% of patients experienced significant pain during carotid and brachiocephalic injections of Hexabrix. No increased incidence of side effects or adverse effects were encountered. In addition, radiographic film quality overall was excellent and comparable to that obtained using conventional contrast agents. Hexabrix is a safe and effective contrast agent for cerebral angiography.

Intravenous injection of the divalent X-ray contrast medium ioglycamic acid ("Biligram") induced intravascular precipitation and sudden death of a patient owing to reaction with his monoclonal macroglobulin. Mice reacted similarly in passive transfer experiments. The corresponding monovalent compound, acetrizoic acid, was also bound to the IgM but did not induce precipitation and had no apparent ill-effects on mice in passive transfer experiments.

Iodipamide and iodoxamate were compared in equimolar clinical dosages in five cholecystectomized chronic bile fistula dogs in which hepatic dysfunction was produced by oral administration of a total dose of 480 and 960 microliters dimethylnitrosamine (DMNA), respectively. After both DMNA dosages, the peak biliary excretion rate for iodoxamate was significantly higher than for iodipamide (p less than 0.01). The peak bile iodine concentration was not significantly different for the two agents (480 microliter DMNA: p less than 0.1; 960 microliter DMNA: p = 0.07). On the basis of this investigation, it is suggested that iodoxamate should not significantly improve the opacification of the biliary system in patients with hepatic dysfunction.

Iohexol 350 mg I/ml (Omnipaque) was compared with the routine contrast medium meglumine, Na-Ca-metrizoate 370 mg I/ml (Isopaque Coronar) in coronary angiography in 30 patients. A randomized, double blind, cross-over design was employed. Angiographic image quality, ECG, heart rate, aortic blood pressure and adverse reactions were recorded. Excellent image quality was obtained with both media. Except for one single event of hypotension, only few and minor changes in the parameters measured were recorded. No distinct difference between the two media was found. Iohexol seems to be suitable for selective coronary angiography.

In a further exploration of idiosyncratic reactions to injections of contrast media, a systematic study of immediate or delayed hypersensitivity in guinea pigs injected with contrast media analogs was performed. No evidence of immediate or delayed hypersensitivity could be ascertained to either contrast media analogs alone, or analogs bound to protein carriers. This does not represent conclusive evidence against the notion of antibody formation as a factor in the production of some adverse reactions, but makes such a pathogenesis less likely.

Urography was performed in 20 patients using the new non-ionic contrast medium iohexol (Omnipaque) and in 22 patients using the conventional ionic medium metrizoate (Isopaque) in a randomized, double blind comparison. Iohexol caused significantly less subjective reactions and less tachycardia than metrizoate. No significant difference between the contrast media was observed regarding the influence on blood pressure, hematologic parameters, or clinical chemical parameters in blood and urine. Urographic films of similar and high quality were obtained with both contrast media.

The degree of albuminuria induced by renal arteriography with the monoacid dimeric contrast medium ioxaglate was studied in 19 patients. Ioxaglate did not cause significant changes in urinary albumin concentrations (median concentration after angiography = 0.022 g/g creatinine). The results with ioxaglate are compared with those of an identically designed study performed earlier with the contrast media metrizoate and metrizamide, in which both caused significantly increased concentrations of urinary albumin (1.1 g/g creatinine and 0.96 g/g creatinine, respectively). The degree of pain/heat sensation following semiselective renal arteriography with metrizoate and ioxaglate was also compared using a visual analog scale in 34 patients. Ioxaglate caused no pain and a significantly lower heat sensation than metrizoate.

Summary Human erythrocytes exposed to visible light in the presence of protoporphyrin showed a pronounced decrease of cell deformability. The photodynamic action of protoporphyrin on red blood cells has previously been shown to cause a.o. an extensive cross-linking of spectrin. As spectrin is presumably involved in processes regulating cell shape and viscoelasticity, conceivably the decreased deformability is attributable to the cross-linking of this protein. Iodosobenzoate evoked a similar decreased cell deformability, due to the formation of disulphide bridges by this agent. These S-S linkages could be reduced by dithiothreitol, with a concomitant change of cell deformability to normal values. Dithiothreitol had only a very limited effect on the protoporphyrin-sensitized decrease of cell deformability and protein cross-linking, indicating that the photodynamic effects cannot be rationalized on the basis of disulphide formation.

Isopaque Coronar, a radiopaque agent, was given (10,000 injections) to 2,028 patients during angiocardiographic studies done over a three-year period. With two exceptions, all complications occurred during right coronary artery injection. Seven cases of ventricular fibrillation, and 5 of marked bradycardia∕asystole, were associated with injection of the medium. Isopaque Coronar is well tolerated by patients during cardiac examinations. Factors which may help to explain the low complication rate are discussed.

The lack of detailed studies of zona pellucida antigens up to the present time is partly due to the difficulty of the purification procedures involved. In the present work 4 porcine zona pellucida antigens were isolated using lithium 3,5-diiodosalicylate as the solubilizing agent, and immuno-affinity chromatography, with immobilized IgG, for purification. This method is believed to be more specific than the previous techniques used. The four zona antigens. ZPI/1 (Mr = 42000), ZPII/1 (Mr = 67000), ZPII/2 Mr=32000), and ZPIII/1 (Mr = 17000), were identified. Based on the reaction of the antigens with antibodies induced by intact and heat-solubilized zonae, it is postulated that only ZPI/1 and ZPII/1 are expressed on the surfaces of intact zonae. The cross reaction between human and porcine zona pellucida antigens is attributed to ZPI/1.

Purified beta toxin from Clostridium perfringens type C was inactivated by the oxidizing agents o-iodosobenzoate (OIBA), oxidized glutathione, and ferricyanide, and by the sulfhydryl group reagents 5,5'-dithio-bis(2-nitrobenzoic acid) (DTNB) and N-ethylmaleimide, iodoacetamide, and iodoacetic acid, causing loss of activity in various degrees depending on the concentration used. The activity of the toxin was not influenced by exposure to 1.0 mm of p-chloromercuribenzoate. The toxin treated by OIBA or DTNB was reactivated by incubation with 2-mercaptoethanol and dithiothreitol. The data suggest that beta toxin contains thiol groups which are essential for the activity. Beta toxin of Clostridium perfringens is produced only by types B and C. It is necrotizing and lethal, but not hemolytic (6). It is thought to be a main factor in necrotic enteritis of animals and man caused by C. perfringens type C. We have purified the toxin extensively (11), and reported that the toxin is a heat labile protein with a molecular weight of approximately 30,000 (12). To study the role played by the toxin in necrotic enteritis of C. perfringens type C, it is important to know the relationship between the functional groups and the activity of the toxin. However, there have been no previous reports on this. We previously found that the toxin is completely inactivated by bubbling of air ( J. Sakurai, Y. Fujii, and M. Matsuura, unpublished data). In this paper, we report that beta toxin is inactivated by some oxidizing agents and sulfhydryl group reagents and that the toxin is reversibly inactivated by mild oxidation.

With the use of an aqueous two-phase system the effect of ioglycamide (Bilivistan) on the binding of testosterone and estradiol to albumin and testosterone-estradiol-binding globulin was investigated using whole human serum. Reduced binding capacity was recorded for TeBG and a reduced apparent association constant for the testosterone-albumin binding was recorded in the presence of ioglycamide in high concentration. The significance of reduced binding of testosterone and estradiol to albumin and TeBG was discussed in relation to side-effects of radiographic contrast media.

In 11 patients the basal cisterns in the posterior cranial fossa were examined with the new water-soluble compound metrizamide. Promising results were obtained when the medium was administered suboccipitally or through the foramen ovale but less favourable after lumbar administration. The clinical tolerance of the compound with regard to short term effects was good.

Isopaque Coronar and Amipaque (metrizamide) were evaluated in a comparative double-blind study of 30 patients with heart disease undergoing selective coronary angiography. Amipaque alone was also used for 9 additional patients undergoing left ventriculography, aortic root injection, and selective coronary angiography. Amipaque resulted in significantly less of a decrease in diastolic pressure and heart rate, reduced chest pain and heat sensation, and longer coronary contrast transit time. Electrorocardiographic parameters and image quality were equivalent with the 2 agents. No pathological changes were noted in the 9 patients undergoing complete angiocardiographic study.

Selective visceral angiography was performed with the ionic, monoacidic, dimeric contrast medium ioxaglate (280 and 320 mg I/ml). Twenty patients with and without disease of the liver and/or pancreas were prospectively and consecutively studied. Changes in the serum activities of ALAT, ASAT, GT, AP, and pancreatic isoamylase and changes in the level of serum bilirubin, prothrombin index and haematocrit were evaluated sequentially before and after angiography. The total volume of contrast medium ranged from 100 to 340 ml per patient and the median dosage was 3.5 ml per kg body weight. There was no statistically significant elevation within the entire group of patients in the measured parameters after angiography when compared with pre-angiographic values. No clinically important toxic effect on the liver or pancreas induced by the contrast medium was found.

Experiments conducted on rabbits confirmed that chlorpromazine potentiates the weak epileptogenic action of Amipaque (metrizamide). Chlorpromazine withdrawal for a period of 48 h suppresses this potentiating effect in the rabbit. Neuroleptic drugs should therefore be avoided in patients examined with Amipaque. In patients under chronic treatment, neuroleptics ought to be discontinued at least 48 h before examination with Amipaque. With the doses and methods used in the present study, diazepam was not as effective as phenobarbital in preventing epilepsy produced by Amipaque. When premidication is needed or when convulsions occur after Amipaque examinations, combined diazepam and phenobarbital therapy ought to be instituted in order to achieve the best control of epileptic reactions.

Amipaque, ioxaglic acid and Isopaque Coronar 300 were compared in a double blind investigation of coronary angiography in patients with ischemic heart disease. Amipaque affected systolic blood pressure and ECG less than the other contrast media. Ioxaglic acid appeared to give more ST and T changes than Isopaque Coronar.