Platinum concentrations in Danish air samples determined by instrumental neutron activation analysis.

Platinum, gold and calcium concentrations of 20 samples of airborne dust collected at two sampling sites between 1995 and 1997 in the city of Copenhagen, which suffers from heavy traffic, were determined by instrumental neutron activation analysis (INAA). INAA of platinum using the 199Au daughter of 199Pt was performed. Two interferences on the INAA of platinum were removed by calculations. The spectral interference on 199Au from the 47Sc daughter of 47Ca was removed by separating the 157-161 keV doublet peak into its components by calculating the counts due to 47Sc from the counts of the parent 47Ca. The contribution of 197Au to 199Au by two neutron absorption was corrected for using the ratio 198Au/199Au in a pure Au standard. From the INAA results, high platinum concentrations are present in air in the range 0.25-2.74 ng m-3 and gold concentrations in the range 0.10-1.96 ng m-3.

Histology and platinum content of sensory ganglia and sural nerves in patients treated with cisplatin and carboplatin: an autopsy study.

Cisplatin is a valuable antineoplastic drug which as a dose-limiting side-effect causes sensory neuropathy, and which therefore is often combined with less neurotoxic carboplatin. It has not been possible to reproduce cisplatin neuropathy in experimental animals, and the neurotoxic mechanism in man is disputed. We investigated post-mortem material from 12 patients and 15 control subjects. Half of the fibres with diameters of > or = 9 microns, or more than 15% of all fibres (P < 0.02), had disappeared in the sural nerves of patients. Signs of axonal regeneration were lacking. The dorsal root ganglia D12 and L2 of some but not of all patients contained necrotic neurons and nodules of Nageotte. The mean volume of the somata was reduced by 18% (P < 0.03). A relation between cumulated doses, treatment free interval and changes in nerve or ganglia was not found. The platinum content was high in all tissues except in the spinal cord when the patient had died shortly after treatment, and it decreased with increasing interval, least so in liver, sensory ganglia and sural nerves. The results support the hypothesis that cisplatin neuropathy is a neuroneopathy rather than a dying-back axonopathy.

The radical scavenging ability of garlic examined in various models.

The influence of an intake of garlic powder (1% added to a standard chow for an 8 week period) on the susceptibility to ventricular arrhythmias under radical reperfusion was investigated in the isolated rat heart perfused with a modified Krebs-Henseleit solution and the generating system hypoxanthine/xanthine oxidase. The incidence of ventricular fibrillation (VF) after the reopening of the LAD was significantly reduced in the garlic group as compared to the untreated controls (VF: 50% vs 89%). As this protective effect might relate to radical scavenging capacities, two in vitro radical generating test systems were chosen where the garlic activity could be determined. Dose-dependently, garlic was able to capture the radicals. Interestingly, only the garlic extract, was active. The ethanol extract hardly showed any radical scavenging ability. According to this result, we concluded that an intact alliin-alliinase system is important for the activity of garlic. Further investigations were done with different tissues under oxidative stress conditions. The kinetics of each organ, were measured chemiluminometrically. Especially liver and kidney of garlic fed rats showed inhibiting effects. Finally, an attempt was made to relate these radical scavenging and lipidperoxidation inhibiting effects to respective garlic compounds. Two substances, allylmercaptane and diallyldisulfide, were proposed.

Determination of aluminium by instrumental neutron activation analysis in biological samples with special reference to NBS SRM 1577 bovine liver.

It was found that a well thermalized heavy water-moderated research reactor can be used to determine the Al content of biological samples without separation of P, Na and Cl. The contribution of the 31P(n,alpha)28Al reaction was corrected from the known concentration of P and the measured effective value. It was found that the contribution is only about 10%. A method is suggested for the determination of Al using instrumental neutron activation analysis.

Effectiveness of garlic on the radical activity in radical generating systems.

The radical scavenging capacity of garlic (allium sativum) has been investigated in vitro in radical generating systems by electron paramagnetic resonance (EPR) and low-level chemiluminescence measurements. Garlic (both the homogenate of 10% in physiological saline solution and its supernatant) was able to reduce the radicals generated by the Fenton reaction and trapped by phenyl-butyl-nitron for EPR measurements. Also radicals present in cigarette smoke could be reduced by garlic as judged from chemiluminescence in the presence of tert.-butyl-hydroperoxide. According to the in vitro measurements garlic contains substances which have significant radical scavenging capacity.

Determination of platinum by neutron activation analysis in nerve tissue from rats treated with cisplatin.

The analytical method used for the determination of traces of platinum and gold in different tissues of Wistar rats is based on neutron activation analysis with radiochemical separation of gold. This separation is performed by electrolytic deposition of gold on a niobium cathode, which ensures the highest radiochemical purity without any spectral interference from calcium or other major elements. Corrections for the nuclear interference from double neutron capture, caused by the gold content of the samples, were found to be insignificant at the levels reported. The following neural tissues were analyzed for their content of platinum: the dorsal root ganglions as well as the dorsal and ventral part of the spinal cord. The highest level of platinum was found in dorsal root ganglions.

Cardioprotective actions of garlic (Allium sativum).

The influence of an intake of garlic powder (1%--corresponding to Kwai/Sapec--added to a standard chow for a 10-week period) on the susceptibility to ventricular arrhythmias under ischemia and reperfusion was investigated in the isolated rat heart (Langendorff preparation) perfused with a modified Krebs-Henseleit solution. The incidence of ventricular tachycardia (VT) and fibrillation (VF) after ligation of the descending branch of the left coronary artery (LAD) (20 min) was significantly reduced in the garlic group as compared to untreated controls (VT: 0% vs. 35.5%; VF: 50% vs. 88%). The size of the ischemic zone was significantly smaller (31.7% vs. 40.9% of total heart tissue). The reperfusion experiments (5 min after 10 min ischemia) revealed similar results (VT: 50% vs. 100%; VF: 30% vs. 90%). The time until occurrence of extrasystoles and VT or VF was prolonged in most cases, and the duration of arrhythmias was abbreviated. No significant alterations in cardiac membrane fatty acid composition could be found. Inhibition of cyclooxygenase by acetylsalicylic acid (ASA) caused a moderate increase in arrhythmias and ischemic zone in the garlic group as well as in untreated controls under the conditions of the present experiments. Thus, it seems that the prostaglandin system does not play a predominant role in the cardioprotective action of garlic. The significance of free radical scavenging activity of garlic for its antiarrhythmic effects has to be established.

Cardioprotective actions of wild garlic (allium ursinum) in ischemia and reperfusion.

The susceptibility to ventricular arrhythmias under the conditions of cardiac ischemia and reperfusion was investigated in the Langendorff heart preparation of rats fed for eight weeks a standard chow enriched with 2% of pulverized wild garlic leaves. The isolated hearts were perfused with a modified Krebs-Henseleit solution. The incidence of ventricular fibrillation (VF) during 20 min occlusion of the descending branch of the left coronary artery (LAD) was significantly reduced in the wild garlic group as compared to untreated controls (20% vs 88%). The same holds for the size of the ischemic zone (33.6% vs 40.9% of heart weight). In the reperfusion experiments (5 min after 10 min ischemia), ventricular tachycardia (VT) occurred in 70% of the wild garlic group vs 100% in untreated controls and VF in 50% vs 90%. The time until occurrence of extrasystoles, VT or VR was prolonged. No significant alterations in cardiac fatty acid composition could be observed. Although the prostacyclin production was slightly increased in hearts of the wild garlic group, inhibition of cyclooxygenase by acetylsalicylic acid (ASA; aspirin) could not completely prevent the cardioprotective effects suggesting that the prostaglandin system does not play a decisive role in the cardioprotective action of wild garlic. Furthermore, a moderate angiotensin converting enzyme (ACE) inhibiting action of wild garlic was found in vitro as well as in vivo that could contribute to the cardioprotective and blood pressure lowering action of wild garlic. Whether a free radical scavenging activity of wild garlic is involved in its cardioprotective effects remains to be established.

A method for personal sampling and analysis of nanogram amounts of formaldehyde in air.

An air sampling and analytical system for formaldehyde measurements based on a solid sampler is described. The samplers were tested on a standard atmosphere in the range of 0.2 to 0.8 mg/m3 dry air. A single 340 mg sorbant section had without drying sections a capacity of 16 micrograms formaldehyde in dry air and 3 micrograms at 70% RH, 23 degrees C. The precision of fluorimetric analysis was better than 6% for samples of 300, 600 and 1200 ng formaldehyde, and the accuracy was better than 10%. The precision of a colorimetric analysis was 12% for a 300 ng sample and 2% for 600 and 1200 ng samples. The accuracy of this method was better than 7%. Both the fluorimetric and the colorimetric analyses are found to be accurate and sensitive analytical methods for the determination of low formaldehyde concentrations. However, if measurements of more than 15 minutes duration are taken and a dessicant is used, the accuracy still remains to be verified. Positive interference from acrolein (5-7% interference when equimolar amounts are present) was found, but there was no interference from other aldehydes.

Experimental normocalcaemic hyperparathyroidism induced by renal venous congestion.

Ligation of the inferior vena cava above the renal veins in male Sprague-Dawley rats produces a predominantly transient renal injury with vascular congestion, tubular degeneration and necrosis with calcification. This is accompanied by impaired renal function with temporary azotaemia, hyperkalaemia, phosphate retention but with a normal calcium level. The parathyroid glands on the second postoperative day show cellular hypertrophy and on the third and fourth days signs of rapid cell proliferation with numerous mitoses. Thereafter the glands remain enlarged.

Fluorometric method for measuring serum lipase activity.

We describe a method for determining lipase (triacylglycerol acyl-hydrolase, EC 3.1.1.3) activity in serum. Emulsified olive oil in tris(hydroxymethyl)aminomethane buffer is used as substrate. The course of the enzymatic reaction is followed by measuring the decrease in fluorescence with time of a fluorescent indicator, 4-methylumbelliferone, added to the substrate, caused by the change in the pH of the substrate solution resulting from the reaction. All measurements are performed at 37 degrees C. The reaction volume is about 2.3 ml, in a Pyrex cuvette. Change of fluorescence and of enzyme activity are linearly related in the range of 77.8 to 389.0 U/liter. An assay can be done in as little as 3 to 5 min, with excellent precision.

Fluorometric assay of serum acid or alkaline phosphatase, either in solution or on a semisolid surface.

We describe enzymatic fluorometric methods for determining activities of serum alkaline phosphatase and of serum acid phosphatase in solution and on silicone rubber pads. 4-Methylumbelliferone phosphate is used as substrate, in either tris(hydroxymethyl)aminomethane or citrate buffer. In solution, the reaction is measured at 37 degrees C in a 3-ml Pyrex cuvette. Measurements on the pads are also made at 37 degrees C, after establishing a stable substrate film by lyophilizing all reagents on the surface of the pads. Only 20 to 30 mul of substrate solution, 50 mul of buffer solution, and 1 to 10 mul of blood are necessary, making a total volume of 51 to 60 mul for each assay. The rate of appearance of the fluorescent 4-methylumbelliferone liberated from 4-methylumbelliferone phosphate by the enzymatic action is measured and equated to enzyme activity. Calibration plots of the change in fluorescence per minute vs. enzyme activity for measurements in solution and on pads show a good proportionality in the range of 30.8 to 633 U/liter for alkaline phosphatase and in the range of 0.265 to 5.3 King-Armstrong units for acid phosphatase, indicating the usefulness of these methods in the clinical laboratory.

Fluorometric assay of serum gamma-glutamyltransferase in solution and on a semi-solid surface.

We describe an enzymatic, fluorometric method for measuring the activity of serum gamma-glutamyltransferase (EC 2.3.2.2) in solution and on silicone rubber pads. N-gamma-L-Glutamyl-alpha-naphthylamide in tris(hydroxymethyl)aminomethane buffer is used as substrate. In solution, measurements are performed at 37 degrees C with use of a reaction volume of 3.0 ml, in Pyrex cuvets. Measurements on silicone rubber pads are also made at 37 degrees C, after establishing a stable substrate film by lyophilizing the reagent for the gamma-glutamyltransferase assay on the surface of the pads. Only 10-50 mul of buffered substrate and serum containing the enzyme to make a total volume of 60 mul are necessary for each assay. The rate of appearance of alpha-naphthylamine fluorescence (lambda ex equals 344 nm; lambda em equals 445 nm), liberated from N-gamma-L-glutamyl-alpha-naphthylamide by the enzymatic action of gamma-glutamyl-transferase, is measured and equated to its activity in serum. Calibration plots of the change in fluorescence per min vs. enzyme concentration for measurements in solution and on pads show a good proportionality in the range of 26.5-265 U/liter, and indicate the usefulness of these methods.