Voltammetric procedure for trace metal analysis in polluted natural waters using homemade bare gold-disk microelectrodes.

Voltammetric procedures for trace metals analysis in polluted natural waters using homemade bare gold-disk microelectrodes of 25- and 125-microm diameters have been determined. In filtered seawater samples, square wave anodic stripping voltammetry (SWASV) with a frequency of 25 Hz is applied for analysis, whereas in unfiltered contaminated river samples, differential pulse anodic stripping voltammetry (DPASV) gave more reliable results. The peak potentials of the determined trace metals are shifted to more positive values compared to mercury drop or mercury-coated electrodes, with Zn always displaying 2 peaks, and Pb and Cd inversing their positions. For a deposition step of 120 s at -1.1 V, without stirring, the 25-microm gold-disk microelectrode has a linear response for Cd, Cu, Mn, Pb and Zn from 0.2 microg L(-1) (1 microg L(-1) for Mn) to 20 microg L(-1) (30 microg L(-1) for Zn, Pb and 80 microg L(-1) for Mn). Under the same analytical conditions, the 125-microm gold-disk microelectrode shows linear behaviour for Cd, Cu, Pb and Zn from 1 microg L(-1) (5 microg L(-1) for Cd) to 100 microg L(-1) (200 microg L(-1) for Pb). The sensitivity of the 25-microm electrode varied for different analytes from 0.23 (+/-0.5%, Mn) to 4.83 (+/-0.9%, Pb) nA L micromol(-1), and sensitivity of the 125-microm electrode varied from 1.48 (+/-0.7%, Zn) to 58.53 (+/-1.1%, Pb nA L micromol(-1). These microelectrodes have been validated for natural sample analysis by use in an on-site system to monitor Cu, Pb and Zn labile concentrations in the Deûle River (France), polluted by industrial activities. First results obtained on sediment core issued from the same location have shown the ability of this type of microelectrode for in situ measurements of Pb and Mn concentrations in anoxic sediments.

Alloy electrodes with high hydrogen overvoltage for analytical use in voltammetry. Some preliminary results.

Liquid mercury and liquid diluted mercury amalgams have been the major electrode systems employed in voltammetry and related methods. This is mainly due to their high overvoltage to hydrogen, which enables the determination of heavy metals (zinc, nickel, cobalt, etc.) and other species with high negative half-wave potentials; the toxicity of mercury and liquid diluted mercury leads to ever increasing restrictions in their use. The use of such systems may even be forbidden in the future, at least in online systems for work in the field. Recent work, carried out in our laboratory, has demonstrated that a non-toxic solid dental amalgam may be used as the electrode material, conveniently replacing mercury. An extension of this work has shown that electrode materials comprising a metal or a compound with low hydrogen overvoltage change their hydrogen overvoltage properties substantially when contaminated with even small amounts of metals or compounds which show high hydrogen overvoltage. This extends greatly the range of potentially available electrode systems and thereby analytical possibilities of voltammetry. This new discovery also makes it possible to produce solid electrodes that have high overvoltage to hydrogen without any use of mercury.

Increased mortality in Dupuytren's disease.

A previous study showed a dip in the prevalence curve of Dupuytren's disease in men over 79 years of age. This may indicate increased mortality. The aim of the present investigation was to study this hypothesis. Four hundred and twenty-six men with Dupuytren's disease, born between 1900 and 1924 were followed for 26 years (1969-1996). Their mortality was compared with that of an age-matched control group of 426 men. In 1996, 361 with Dupuytren's disease and 336 in the control group had died. Overall, patients with Dupuytren's disease had a significantly increased mortality of 22%. The mortality was highest among those with onset of disease before the age of 60. In this age group men with Dupuytren's disease had 70% higher mortality than that of the control group. Disease duration did not seem to influence the mortality.

Replacement of destroyed metacarpal heads by autografting metatarsal heads.

A surgical procedure of replacing a destroyed metacarpal head with a metatarsal graft is described. With this method internal fixation with foreign material as well as postoperative immobilisation can be avoided. A follow up of 25 autotransplantations in rheumatoid patients is presented, showing no complications and fair function of the new operated joint.

Respiratory effect of THIP, a GABA-agonistic analgesic, during halothane anaesthesia.

THIP, 4, 5, 6, 7-tetrahydroisoxazolo (5,4-) pyridin-3-ol, is a GABA-agonistic drug with analgesic effect, but apparently without respiratory depressant properties in awake subjects. The effect of THIP on the CO2 ventilation response was tested before, during and at the end of halothane anaesthesia in six male patients and compared to a control group. As there was no indication of respiratory depression by THIP, the drug may have a future in the treatment of postoperative pain if an analgesic effect is confirmed under clinical conditions.

Arthrodesis of the wrist joint in rheumatoid arthritis.

Fifty six fusions of the wrist joint were performed using a slight modification of the method described by Mannerfelt and Malmsten (1971). All but one of the patients had rheumatoid arthritis. The patients were reviewed one to eight years after the operation. Ankylosis in useful position was achievedin nearly 100 percent of the cases. The operation is simple and does not require any special instruments, but x-ray facilities in the operating room are necessary. Normally there is no need for any kind of external immobilisation.

Dupuytren's disease--the influence of occupation and previous hand injuries.

The influence of handedness, work and previous hand trauma is studied in 901 persons with Dupuytren's disease, collected in an epidemiological study of 15,950 citizens in a small, Norwegian town. Dupuytren's disease occurred in all occupational groups, but the prevalence was higher and the contracture more severe in people doing hard manual work than in people doing light or non manual work. Persons with Dupuytren's disease has sustained previous hand trauma more frequently than the general population, and the interval between trauma and first sign of disease was usually a few years. Previous hand injuries were definitely more common among people doing hard manual work, but even when these were excluded from the work material, Dupuytren's disease was still more common among people doing hard manual work, than in people doing light or non manual work. The study has indicated that Dupuytren's disease in certain cases is precipitated and/or aggravated by both work and definite hand injury.

Serum diazepam and serum creatine kinase after intra-muscular injection of diazepam in two different vehicles.

Serum diazepam concentration and serum creatine kinase activity (serum CK) were measured in 35 patients (who were divided into three groups (A, B, and C)), over a period of 24 hours after administration of diazepam. An increase in serum CK was regarded as an indication of local muscle injury. In group A, diazepam in a polyethyleneoxydricinolate vehicle was injected intramuscularly; in group B, diazepam in a propyleneglycol-ether alcohol vehicle was injected intramuscularly; and in group C, diazepam was administered orally, combined with intramuscular administration of the vehicle used in group B. The investigation was double-blind and randomized. Serum diazepam absorption expressed as the area under the concentration curve was identical in groups A and C and significantly higher than in group B. Serum CK rose in all groups. The differences among the groups were not significant. There were considerable individual variations in all three groups, and almost half the patients showed no increase in serum CK at all. No negative correlation was found between serum diazepam and serum CK. Thus no effect of muscle injury--if present--on absorption rate could be demonstrated.

Knuckle pads in Dupuytren's disease.

Knuckle pads are not exclusively found in persons with Dupuytren's disease, but they occur four times more often in these patients than in the general population (in Norway). Occurrence of knuckle pads in persons with Duputyren's disease does not seem to imply a higher predisposition or a more aggressive disease.

Dupuytren's disease--initial symptoms, age of onset and spontaneous course.

647 men and 254 women with Dupuytren's disease of the hands were questioned about how, where and when the disease had started. Usually the disease started in the right hand, and nodules in the ulnar part of the palm were the first symptom in 90%. In 10% of the cases with bilateral disease, it started simultaneously in both hands. One woman and two men noticed the first symptom before 10 years of age. In about 50% of the men, the disease started between 40-59 years of age (women 40-69 years). In men the contracture increased rather constantly during the first twenty years, followed by a stationary phase from about 20 to thirty-five years of duration, whereafter it definitely decreased. In women the disease increased gradually with the duration of the disease.

Wear of the polyethylene head of the Oscobal prosthesis.

Ten hemiarthroplasties were performed with the Oscobal (Daubenspeck) his prosthesis, which consists of a metal stem and a nonrotating ployethylene head. Five patients died 1-150 days after the operation. Signs of massive wear of the polyethylene head were demonstrated in four out of the five patients still alive 16-28 months after the operation. We can therefore not recommend the Oscobal system for hemiarthroplasty of the hip.

Dupuytren's disease--a study of the pattern of distribution and stage of contracture in the hand.

The distribution and stages of contracture in the digits are examined in 901 persons with Dupuytren's disease and collected into an epidemiological study of 15,950 persons in a small Norwegian town. The frequency of contracted digits counted from the total number of affected hands, are for men (women in parentheses): Thumb 3.0% (0.6), Index finger 1.2% (1.7), Middle finger 28.3% (27.9), Ring finger 85.1% (92.3) and Little finger 45.4% (39.5). The most common combination of affected fingers are ring and little fingers. At corresponding ages, the contracture is more severe in men than in women, and more severe in the right than in the left hand. With the exception of the index finger, the degree of contracture increases from the thumb to the little finger, 29% of the men and 12% of the women examined had contracture of such an extent that surgical treatment was advisable. Only 5.7% of the men and 3.1% of the women had been operated on because of the disease, which indicates that operation statistics are based upon very selected patients. Many aspects of this disease can only be properly studied in epidemiological material.

Flexor tendon synovectomy of the hand in rheumatoid arthritis. A follow-up study of 201 operated hands.

A follow-up study of 201 flexor tendon synovectomies of the hand in patients with rheumatoid arthritis is presented. The operations were performed from 1/2-49 years after onset of the disease, and the patients were between 16 and 76 years of age. The follow-up study is based on questionnaires and, in addition, 78% of the patients also had a physical re-examination. The follow-up time spanned 12-78 months. Nearly 70% of the operated hands were subjectively improved; the others were unchanged or worse. The poor results were often caused by progression of arthritis in finger joints. Recurrence of the tenosynovitis was observed in about 37% of the hands, but in very few to such an extent that reoperation has been necessary.

Small heparin doses as prophylaxis against deep-vein thrombosis in major surgery.

100 patients were treated either with heparin 5,000 i.u. every 12 hours or placebo in a double-blind, randomized, prospective trial. The treatment was commenced 1-3 hours before surgery and was continued for 6 1/2 days. The criteria for the selection of patients and the principles on which the treatment and investigation schedules were based corresponded generally to those laid down by Kakkar et al. (1972). The incidence of deep-vein thrombosis of the lower extremities was 6% in the group treated with heparin and 20% in the placebo group. The decisive diagnosis of thrombosis was based on the scanning of the lower extremities after administration of I125-fibrinogen. No case of pulmonary embolism occurred and no complications because of the treatment were noted. We propose to institute investigations on a larger scale to evaluate the prophylactic value of small heparin doses with respect to pulmonary embolism.