[Assessment of qualifications of physicians].

A methodology of estimating the professional level of physicians with the help of tariff scale is described. The tariff coefficients are determined by the correlation between the official salaries of physicians, having a qualification category, and a background monthly salary taken as a unity. The mean tariff coefficient of physicians can serve for public health bodies and insurance organizations as an assessment indicator of professional possibilities of an institution, complexity of the work performed, the cost and quality of medical services. For the leading staff of the institution the methodology is supplemented by the estimates of a number of intermediate indicators and their integral assessment which helps analyse the basic factors influencing the general level of physicians qualification.


[Several aspects of improvement in the training of surgeons at medical institutes].

This paper summarizes the experience gained in the training of surgery specialists at a medical institute and determines the main shortcomings of undergraduate and postgraduate specialization. A sociological survey carried out in the groups of subinterns indicated low effectiveness of preinstitute and intrainstitute professional orientation. Great emphasis is being placed on increasing the quality of training on fundamental sciences and preclinical disciplines. A positive appreciation is being given to the long application of the unified methodological system of specialists training, the use of the syndrome method of training at the graduate year, which is based on maximum activation of clinical thinking, motivated approach to the development of practical knowledge and skills. The important role of continuity in the training of surgeons in the subinternship and internship is stressed.


The effect of surgical intervention on rehabilitation time in patients with thoracolumbar and lumbar spinal cord injuries.

One hundred forty-seven patients with unstable low thoracic and lumbar fractures were examined. All patients had significant neurologic injuries. Ninety-one patients exhibited incomplete lesions whereas fifty-six had complete lesions. Age, sex, cause of injury, fracture location, fracture mechanism, and complications were recorded and analyzed. The average follow-up was 25 months (range 2-148). Incomplete neurologic lesions demonstrated a significant increase in ASIA motor points if both decompression and stabilization were performed at the same operative sitting. When decompression was performed before stabilization a decrease in improvement was noted. Patients with complete lesions demonstrated a significant reduction in rehabilitation time if stabilization was augmented with sublaminar wires rather than Drummond wires or Harrington rods alone.


Blood conservation in spinal surgery. Review of current techniques.

The potential dangers of homologous blood transfusions are well known. Among the more serious complications of such therapy are hepatitis and acquired immune deficiency syndrome. As a result, blood conservation has become a topic of great interest to both physicians and patients. Numerous studies exist documenting the effectiveness of preoperative autologous blood donation, intraoperative autologous transfusion, hypotensive anesthesia, and postoperative blood salvage. Perioperative recombinant human erythropoietin is a promising new adjunct to these techniques. Careful surgical technique is crucial to the success of these complex modalities. In the absence of tumor, systemic infection, or gross wound contamination, these modalities should be considered when a spinal procedure is planned in which homologous blood may be required.


The form and structure of the extruded disc.

There are no detailed data in literature concerning the histologic nature of the sequestered (extruded) lumbar disc, and on the frequency with which an extruded fragment, a prolapse or a protrusion are found at surgery. A prospective analysis of 100 consecutive cases of sequestered lumbar disc herniation submitted to surgical treatment revealed this group to represent 28.6% of all cases operated on for lumbar disc herniation. Patients (both male and female) with sequestered lumbar discs are significantly older than those with prolapsed (P < 0.01) and protruded (P < 0.001) discs. Single extruded fragments (n = 68) were twice as frequent as multiple ones (n = 32). The general belief that a 'sequestered (extruded) disc' is almost invariably composed of nucleus pulposus is not substantiated by this study: In 54 cases the extruded fragment consisted predominantly of nucleus material, whereas in 44 cases it consisted mainly of end-plate material. Multiple as well as recurrent sequestered fragments almost always consist of end-plate material. These findings may reflect the result of metabolic alterations in the course of disc degeneration.


Cauda equina syndrome in patients undergoing manipulation of the lumbar spine.

Cauda equina syndrome has been implicated as a potential complication of spinal manipulation. A review of the literature from 1911 to 1989 revealed ten reported cases of cauda equina syndrome in patients undergoing manipulation without anesthesia. This article presents three new cases where a temporal association was found between the onset of cauda equina symptoms and lumbar manipulation. The type of manipulation administered and the relationship between the treatment and symptoms is reviewed. In each of these cases both the chiropractic practitioner and the emergency room physician failed to comprehend the nature of the problem and take appropriate action. As a consequence, the patients went untreated for several days. This may have led to residual symptomatology. It is concluded that patients who present with bowel or bladder disturbances, leg weakness, or rectal and genital sensory changes after manipulation, be recognized as experiencing a cauda equina syndrome.


Chronic donor site pain complicating bone graft harvesting from the posterior iliac crest for spinal fusion.

To explore the relationship between surgical approach and chronic posterior iliac crest donor site pain, 151 bone graft harvests with follow-up periods longer than 1 year were evaluated using a detailed questionnaire and follow-up clinical visits. There was no difference in the incidence of chronic donor site pain between harvests performed through the primary midline incision versus a separate lateral oblique incision (28 vs 31%). Twice as many donor sites harvested for reconstructive spinal procedures were reported as having chronic pain as compared with those harvested for spinal trauma, regardless of approach used (39 vs 18%). The association of chronic donor site pain with residual back pain was also greater in the spinal reconstructive group. Thus, it appears that incidence of chronic donor site pain is more dependent on diagnosis than on surgical approach.


The back pain of bus drivers. Prevalence in an urban area of California.

A stratified random sample of 195 subjects was selected from the membership of an urban transit union in California, two thirds consisting of motor coach operators and one third serving as a nondriving comparison group. Based on an orthopaedic medical history and physical examination, 80.5% of drivers were found to be experiencing back or neck pain at the time of examination, in contrast with 50.7 percent of nondrivers, itself a sizable percentage. For both groups, most pain was mild, (53.9 and 29.9%, respectively). The amount of severe pain was essentially the same in the two groups (10.2% and 9.0%). Both groups were most subject to low back pain. Drivers were most distinctive for movement-related pain in the cervical spine. They were also more subject in any part of the spine to postural pain. The latter finding suggests the need to introduce ergonomic and scheduling changes in the work of operating a motor coach. Drivers more than nondrivers struggled against their pain by doing exercise, seeking professional treatment, and taking medications, indicating that spinal disorders constitute a prominent health concern for workers in this occupation.


Lumbar surgery for 56 limbus fractures emphasizing noncalcified type III lesions.

The clinical, radiologic, and surgical procedures performed for 56 out of 59 patients with Type I-IV fractures of the vertebral limbus were reviewed, stressing the diagnostic and operative management of noncalcified Type III (NC III) lesions. Forty-four calcified Type I-IV (CA I-IV) limbus fractures, interpreted as routine disc herniations on magnetic resonance imaging scans, were correctly identified as limbus fragments on computed tomographic and myelographic/computed tomographic studies, whereas 15 NC III lesions were mistaken for disc herniations alone on all three radiographic examinations. The preoperative recognition of the CA I-IV and NC III fracture types proved essential to the successful resection of five Type I, five Type II, 36 Type III, and ten Type IV fragments through extended laminotomies, hemilaminectomies, and laminectomies with the down biting curette, tamp, and mallet technique. In the absence of routine disc herniations, expanded standard dissectomies to the superior or inferior pedicular levels allowed for the identification and removal of NC III fractures.


Effect of reduced frequency of training and detraining on lumbar extension strength.

To investigate the effect of reduced frequency of training and detraining on lumbar extension strength, 50 subjects (34 men, aged 34 +/- 11 yrs; and 16 women, aged 33 +/- 11 yrs) were recruited from ongoing strength training programs. Initial training consisted of 10 or 12 weeks of variable resistance lumbar extension strength exercise to volitional fatigue 1, 2, or 3 times a week. After the initial training, subjects reduced the frequency of training to once every 2 weeks (n = 18) or once every 4 weeks (n = 22) for 12 weeks. Only the frequency of training was changed; the mode, volume, and intensity of exercise remained constant for both reduced frequency of training groups. An additional ten subjects terminated training and acted as controls (detraining group). Isometric lumbar extension strength was evaluated at seven angles through a 72 degree range-of-motion before training, after training, and after reduced frequency of training or detraining. Analysis of variance with repeated measures indicated that lumbar extension strength improved (P < or = 0.05) for all groups after the initial 10 or 12 weeks of training. After 12 weeks of reduced training, the once every 2 weeks and once every 4 weeks groups showed no significant reduction in lumbar extension strength at any angle tested, whereas the detraining group demonstrated an average 55% reduction in strength. These findings indicate that isometric lumbar extension strength can be maintained for up to 12 weeks with a reduced frequency of training as low as once every 4 weeks when the intensity and the volume of exercise are maintained.


The arcuate foramen. Variability in distribution related to race and sex.

The occurrence, varieties, and distribution by race and sex of the arcuate foramina observed in 1,000 consecutively seen cervical spine radiographs are reported. The complete foramen is significantly more common in males, without any racial predilection. The partial foramen is commonest in white females. The rate of occurrence seems independent of age.


Lumbar posterior marginal node (LPMN) in adults. Report of fifteen cases.

This report concerns 15 adults (nine men and six women) who experienced lumbar and sciatic pain associated with an unusual defect of the edges of the vertebral bodies together with a small bony ridge protruding into the spinal canal. This lesion was well demonstrated by computed tomography and easily differentiated from the posterior longitudinal ligament or herniated disc calcifications, as well as from posterior degenerative ridge osteophytes. This lesion looked like the so-called lumbar posterior marginal node. First described in adolescents, this entity was considered as a traumatic fracture of the posterior ring apophysis. Recently, identical cases were noted in young adults in the absence of previous trauma, which were a particular type of marginal cartilaginous node. In the cases reported here, the computed tomographic scans suggested several mechanisms of formation of the vertebral lesion: a variant of marginal cartilaginous nodes; traumatic avulsion; avulsion related to disc herniation; and fusion of the avulsed bony fragment with the vertebral body.


Comparison of individual characteristics and death rates of disabled-worker beneficiaries entitled in 1972 and 1985.

The many changes to the Disability Insurance (DI) program that took place during the early 1980's suggest that there may be significant differences in the characteristics of newly awarded beneficiaries over time. This study compares two cohorts of newly entitled beneficiaries--one from 1972 and the other from 1985--in order to assess changes in individual characteristics and death rates between the pre-1980's and the late 1980's. The 1985 cohort had a greater percentage of beneficiaries with mental impairments and a lower percentage with diseases of the circulatory system. The 1985 cohort was also younger, more educated, had higher primary insurance amount levels, and had greater percentages of women and black beneficiaries. Although the death rates and survival curves for both cohorts were very similar, differences in the curves occurred for some covariate subgroups. When the populations were standardized, the estimated percentages of beneficiaries who survived 5 years after entitlement were 78 percent for the 1972 cohort and 77 percent for the 1985 cohort.


The economic status of the aged.

This article discusses what is known about the economic status of the aged. Numerous complexities involved in the assessment of their status are discussed. Compared with most other recent assessments, this study finds a less favorable status for the aged relative to other age groups. The focus is on an examination of detailed age groups, rather than summary aged and nonaged groups--thus providing a more complete picture of age differences. More than most other assessments, this study stresses uncertainty about the relative status of the aged and emphasizes what we do not know. It stresses that better adjustments for differences in needs among age groups and other subgroups of the population are necessary. It emphasizes that consistency between the definition of resources and the specification of needs is essential. Also discussed is the vulnerability of the aged to economic risks. Major findings include: Median cash income is highest for middle-aged family units and lowest for the oldest and youngest units. The poverty rate for aged persons is above the rates for other adult age groups, but below the rate for children. When noncash income is considered in addition to cash income, the income of the aged tends to improve relative to that of the nonaged, but serious measurement problems exist. When wealth is considered in addition to cash income, the economic status of the aged improves relative to that of the nonaged.


Workers' compensation: 1984-88 benchmark revisions.

About 93.1 million workers were covered under workers' compensation laws in 1988--an increase of 11 percent from the 1984 total. Benefit amounts totaled $30.7 billion--an increase of about 56 percent since 1984. Of the total payments made under the workers' compensation program, $17.6 billion went to disabled workers, $1.6 billion to their survivors, and $11.5 billion for medical care. The Social Security Administration (SSA) is interested in measuring economic security in the United States, and workers' compensation plays a large role in that measurement. This article represents one part of our overall effort to determine the roles the various income-maintenance programs play in helping citizens of the United States achieve economic security. The figures presented here provide readers with an opportunity to review workers' compensation program operations during much of the 1980's. Workers' compensation is also important to SSA because that program is directly related to the Social Security Disability Insurance program. Since 1965, Social Security disability benefits have been subject to reduction if the beneficiary also receives workers' compensation and the combined benefits exceed 80 percent of previous earnings. In addition, SSA has been directly involved in providing income maintenance for disability from work-related diseases since 1969 when the Federal Black Lung benefits program was established.


Neutralization of the antithrombotic effects of heparin and Fraxiparin by protamine sulfate.

In general, the in vitro anti Xa activity of low molecular weight heparins is neutralized to a lesser degree than the anti Xa activity of unfractionated heparin. To determine whether these differences occur in vivo, a rabbit stasis thrombosis model and a rat laser-induced thrombosis model were utilized. In the laser model, a similar degree of neutralization of the antithrombotic activity of heparin and Fraxiparin was obtained. However, in the stasis thrombosis model, significant antithrombotic activity of Fraxiparin remained after equigravimetric protamine administration. Ex vivo APTT, thrombin time, Heptest, amidolytic anti Xa and anti IIa assays were performed. A coefficient (r = .806) was obtained for the correlation of Heptest activity to antithrombotic effect in the stasis thrombosis model, while the coefficients obtained for the other tests ranged from .152-.570. However, after neutralization by protamine, the thrombin time exhibited the highest correlation coefficient (r = .685) between ex vivo activity and residual antithrombotic effect. Since Fraxiparin retains antithrombotic activity after protamine administration, clinical benefit may be observed for this low molecular weight heparin as compared to unfractionated heparin after neutralization.


Does Lp(a) lipoprotein inhibit the fibrinolytic system?

Lp(a) lipoprotein contains a unique apolipoprotein, apolipoprotein (a), that has a striking homology with plasminogen. This homology has brought forward speculations as to an inhibitory effect of Lp(a) lipoproteins on fibrinolysis. The present investigation was undertaken to study the influence of Lp(a) lipoprotein on the fibrinolytic system. In an in vitro model, we have studied the influence of purified Lp(a) lipoprotein on plasminogen activation by tissue plasminogen activator (t-PA) in the presence of soluble fibrin. Increasing concentrations of Lp(a) lipoprotein (0-32 mg/dl) did not inhibit plasminogen activation by t-PA in the presence of thrombin or bathroxobin digested fibrinogen. When purified Lp(a) lipoprotein was added to whole blood, the degree of fibrin degradation obtained following standardized coagulation, as evaluated by the generation of D-dimer, was not reduced. D-dimer levels in plasma and in serum after standardized coagulation, as well as conventional parameters for evaluation of the fibrinolytic system, were determined in 10 individuals with high and 10 individuals with low levels of Lp(a) lipoprotein. No differences in the fibrinolytic parameters were observed between the groups. Thus, we found no evidence that Lp(a) lipoprotein interferes with the fibrinolytic process in the present experiments.


Interaction of heparin with myosin ATPase: possible involvement with the hemorrhagic activity and a correlation with antithrombin III high affinity-heparin molecules.

Up to 50% of [35S]-heparin molecules prepared from rat skin bind to rabbit muscle myosin ATPase, in a concentration dependent manner, producing a stable complex with a dissociation constant of 3 x 10(-7) M. The [35S]-heparin in the complex has a distinct electrophoretic behaviour and is precipitated by TCA together with myosin. Other [35S]-glycosaminoglycans, namely, heparan sulfate, dermatan sulfate and chondroitin sulfate also prepared from rat tissues are unable to form complexes with the enzyme. Among the sulfated glycosaminoglycans obtained from different sources only heparin is able to displace the bound [35S]-heparin from the ATPase. Heparin with high affinity for antithrombin III, prepared by antithrombin-affinity chromatography, dislodges up to 90% of the bound [35S]-heparin. Furthermore, antithrombin III-high affinity heparin shows a high affinity for myosin ATPase when compared to antithrombin III-low affinity heparin which shows a low affinity for the enzyme. It is also shown that myosin ATPase inhibits the "in vitro" plasma anticoagulant activity of heparin. These are suggestive that the special structure of the heparin molecules needed for the binding to antithrombin and myosin ATPase bears important similarities. The mechanism of the hemorrhagic effect of heparin is discussed in view of these interactions.


Reversibility of fibrinogen fragment D1 binding to human platelets: comparison with native fibrinogen.

To gain further insight into the mechanism responsible for rendering fibrinogen bound to stimulated platelets irreversible to dissociation by EDTA or excess unlabeled fibrinogen, the present study compared the reversibility of platelet interactions with fibrinogen and its plasmic degradation product, fragment D1. Like fibrinogen binding, the binding of fragment D1 became progressively less sensitive to dissociation by EDTA, PGE1, or excess unlabeled fibrinogen. Thus in the presence of EDTA, 70 +/- 19% and 55 +/- 24% (mean +/- S.D., n = 9) of bound fragment D1 failed to dissociate from platelets 60 min after stimulation with 0.15 U/ml thrombin or the combination of 5 microM ADP and 5 microM epinephrine, respectively, compared to 75 +/- 8% and 52 +/- 17% of platelet-bound, intact fibrinogen. In contrast, platelet stimulation with chymotrypsin or Zn+2 failed to support the development of irreversible fragment D1 or fibrinogen binding. Only 8 +/- 6% and 9 +/- 3% of bound fragment D1 remained associated with chymotrypsin- or Zn+2-treated platelets, respectively, compared to 7 +/- 11% and 15 +/- 6% (mean +/- S.D., n = 3) of platelet-associated fibrinogen. These observations suggest that irreversible fragment D1 and fibrinogen binding to platelets occurs by a similar mechanism that requires neither fibrinogen alpha chain 95-97 or 572-574 RGD sequences nor multivalent ligand-receptor interactions.


Characterization of a Ca (II)-independent monoclonal antibody that lacks reactivity with Gla-domainless human factor VII.

Eight murine monoclonal antibodies to human factor VII have been produced and characterized. As tested by direct ELISA, all antibodies bound to immobilized factor VII and this interaction did not require Ca(II). On immunoblotting three antibodies reacted only with native factor VII and activated factor VII (rFVIIa), two with native factor VII, activated factor VII and with the light chain of reduced activated factor VII and three with reduced activated factor VIIa (light chain) only. When coupled to Sepharose five antibodies were capable of immunodepleting factor VII from normal plasma and inhibited coagulant activity with varied potencies. Among these antibodies, one (10C12.2) had peculiar characteristics, lacking reactivity with Gladomainless FVII and with the Ca(II)-dependent conformation. This antibody has been used to develop a two-site ELISA which appears to measure native factor VII but not poorly carboxylated, inactive forms of the molecule.


Enzyme-linked immunosorbent assay of human factor VII based upon a monoclonal antibody that recognizes the native conformation of the protein.

An enzyme-linked immunoassay (ELISA) was developed for measuring human factor VII antigen using two monoclonal antibodies, one of them reacting only with fully carboxylated factor VII. This assay permits to measure factor VII antigen in concentrations ranging from 0.78 to 100 ng/ml, with within- and between-assay coefficients of variation of less than 7%. In 53 normal subjects, 32 patients with liver cirrhosis, 21 pregnant women and 53 patients on oral anticoagulant therapy the plasma levels of FVII antigen were very similar to those of factor VII coagulant activity measured with a bioassay. The ELISA also gave very similar values of factor VII antigen in plasma and in serum, and in plasma before and after exposure to cold, indicating that the assay is not affected by factor VII activation. In five of 8 patients with severe congenital deficiency of factor VII values of factor VII antigen were higher than those of factor VII activity. The close concordance of factor VII values obtained by ELISA and bioassay in the majority of plasmas, including those from patients on oral anticoagulant therapy, indicates that the assay measures native factor VII and can perhaps replace the bioassay systems in clinical conditions associated with normal or high levels of factor VII.


Hemostatic effects of ephedrine.

The effects of ephedrine on coagulation and on fibrinolysis were studied in six healthy volunteers. Six volunteers, matched by age and sex, served as untreated controls. Ephedrine was found to significantly prolong mean bleeding time by 2 minutes. Ephedrine has been proposed to activate fibrinolysis, but we found no increased tPA activity. The platelet count, APTT, factor VIII and von Willebrand factor remained constant. In an in vitro study ephedrine was found to inhibit platelet aggregation induced by adrenaline and, to some extent, also by ADP. The inhibition was competitive and not mediated via beta 2 adrenoceptor stimulation. It is concluded that there are hemostatic effects of ephedrine and that these may be of clinical relevance, the drug being very commonly used in connection with procedures where blood loss as well as venous thromboembolism are considerable problems.


[Serious complications related to use of corn starch powder on surgical gloves].

Cornflour has been used as a lubricant on surgical gloves since 1947. Serious complications have been reported after deposition of cornflour powder in the human body. The best known complication is granulomatous peritonitis, but cornflour granulomas have also been found in the heart, the kidneys and the central nervous system. Maltesercross, when seen in polarized light in the microscope, is pathognomonic. Malignancy and other granulomatous inflammations are actual differential diagnoses. Nowadays gloves free of lubricating powder are commercially available.


[4-year experiences with nasal continuous pressure in the treatment of obstructive sleep apnea syndrome].

We investigated the compliance, effects and side effects of nCPAP in 27 patients with obstructive sleep apnea syndrome, 26 of whom filled in a mailed questionnaire. Mean treatment time was 20 months (range 1-46 months). 24 patients (92%) still used their nCPAP. 15 patients (63%) used nCPAP six or seven nights per week, and 19 patients (79%) at least three nights per week. The effect was best and the use more frequent in patients with more than nine oxygen desaturations per hour during one night. Mean body weight was reduced from 103.5 to 100.9 kg (p = 0.01). Improved professional performance and interpersonal relationships were reported, each in ten persons. 19 patients stopped snoring and no longer felt sleepy during the day. The main reasons for interruption of treatment were travelling and nasal congestion. Some help was needed to treat skin irritation and mucosal dryness. In conclusion, most patients accepted nCPAP as long term treatment and reported improvement in quality of life.


[Quality control of leukocyte filtration of blood products].

Quality control of leucocyte depleted blood products has become a problem since the introduction of bedside leucocyte filtration. At our Blood Centre, this problem has been circumvented by testing a sample taken as the filtration is completed by sealing off a 10 cm piece of tubing just under the filter. We have tested four brands of erythrocyte filters, Pall RC100, Erypur Optima b, Sepacell R-200A and Sepacell R-500A(II) using two erythrocyte concentrates for each filter. We have tested two brands of thrombocyte filters, Pall PL100 with 6-8 thrombocyte concentrates, and Sepacell PL-5A with 2-6 concentrates. No transfusion should give more than 5 x 10(6) leucocytes. Pall PL100, Pall RC100 and Sepacell R-500A(II) met the criteria.


[Hearing loss in autoimmune diseases].

Several autoimmune disorders are associated with inner ear involvement. The resulting sensorineural loss of hearing may be improved by treatment with immunosuppressive agents. We describe a patient with oral ulcerations, systemic vasculitis, iridocyclitis and bilateral sudden deafness. After a course of systemic steroid treatment the hearing improved. Atypical Cogan's syndrome is the most likely diagnosis.


[Compulsory reporting of accidents and injuries in somatic hospitals. Is the existing system adequate for quality assurance?].

Doctors in Norway are obliged by law to submit reports to central authorities about injuries and risk of injury arising from medical equipment and drugs. Deaths following health care procedures must be reported to the police, and major injuries to the County Medical Officer. Most hospitals have their own rules requiring health care providers to report all incidents resulting in injury or risk of injury. The author contends that fewer than 5% of the injuries are reported. Neither the law, nor the hospital rules, require that the incidents in general are evaluated, with feed-back to the care providers. Most incidents do not seem to be evaluated. There is much left to do, both in building a set of regulations and in implementing better hospital practice, by using records of injuries and mishaps to identify and prevent further mishaps.


[Medical ethics and quality assurance].

Quality in medicine is by definition an ethical aim. In its common form the programme of quality control is directed at the accurate measuring of the output of health care. This programme has a good ethical foundation. We ought to know much more about results and complications, both of diagnostic and of therapeutic procedures. However, the quality assessment programme, also has potential dangers from an ethical point of view. The main problem is that it may tend to focus on simple, technical, measurable short-term indices, giving insufficient attention to important human and ethical factors. Therefore the quality control programme needs to be supplemented by other methods.


[Being a patient--patients' view on the quality of treatment].

The technical quality of medical treatment in Norway is generally high, whereas the functional quality of the same medical treatment varies considerably. This becomes quite apparent from complaints from patients on treatment and care. Patients expect health care services to be of consistently high quality. They increasingly expect good quality medical treatment, just like they, as consumers, expect quality goods and services elsewhere in society. Realization of the Norwegian Medical Association's resolution on medical quality assurance is an important measure, both in assuring and improving the overall quality of the care and treatment of patients.


[Drug therapy of Parkinson disease].

The author reviews the various strategies for treatment of Parkinson's disease by modern drugs. Either levodopa or a levodopa agonist is recommended for treatment of early Parkinson's disease. For long-term treatment, a combination of levodopa and levodopa agonist is preferable, since combined treatment appears to cause fewer side effects and motor fluctuations than does high dose monotherapy. Selegeline may be added, both in initial and long-term treatment. However, it is still uncertain whether selegeline acts only as a dopamine agonist, or also has a neuroprotective effect.


[Prevention of unwanted pregnancies in adolescents in a suburb--is it valuable?].

By counting cases of induced abortion among girls aged 15-19 years from 1988 to 1990 in Stovner district, Oslo, we evaluated a programme to prevent unwanted pregnancies among young women. The programme consists of several approaches, including free health services for teenagers at a special youth clinic, more education, at school and at youth clubs etc, in the use of contraceptives, and alcohol-free weekend arrangements. From 1988 to 1990 the number of abortions decreased from 35/1000 to 15/1000. Although this difference is significant (p < 0.01), one must be careful in drawing conclusions, owing to the small size of the sample.


[High-cost therapy. Ethical principles of allocation of scarce resources].

This article raises some ethical problems concerning high-cost therapy for malignant haematological diseases. The problem of setting priorities is discussed within the framework of utilitarianism, right-based theories and the contractarian theory of John Rawls. It is argued that utilitarianism can provide precise answers, based on the principle of allocative efficiency. However, this is not the only objective of a public health care system. The right-based approach is discussed, but sufficiently precise definitions seem hard to formulate. The contractarian approach is regarded as interesting, since it tries to address the question of trade-offs between objectives of allocative efficiency and distributive fairness.


[Drug therapy of depression in general practice].

The authors advocate use of the Montgomery-Asberg Depression Rating Scale in general practice as a screening instrument for depression. A score of 20 and above for more than two weeks indicates a need for treatment with antidepressant drugs. The treatment should continue with full dosage for at least two months after the patient has been cured. In order to maintain the patient's quality of life, reduce risk of drug-related toxicity and improve compliance, we recommend alfa-2-receptor blocker, a selective 5HT-re-uptake inhibitor or a selective monoamino-oxidase A inhibitor as the first drug choice for treatment of depression by general practitioners. Monitoring serum levels of the drug may be helpful, especially in persons who do not respond to treatment.


[Sexual contacts between psychotherapists and patients. A review of recent American literature].

According to research in the USA, most psychotherapists reported sexual attraction to one or more of their patients during their career. Only a small minority, however, engaged in sex with their patients. There is a subgroup among offenders (i.e. repeaters) whose views on therapist-patient sex are distorted and grossly at variance with standard professional ethics. Nine of ten patients who have been involved in sex with their therapists are harmed by it. The clinical problems they present resemble those of incest and rape victims. In terms of prevention it seems worthwhile to train students and psychotherapist trainees in ethics and in how to handle sexual feelings. Efforts to rehabilitate offenders have met with little success so far. Prevalence of doctor-patient sex does not seem to differ across most clinical medical specialties.


[A project on eating disorders. Increasing of competence within mental health services in treating severe eating disorders].

We describe a two-year education programme for health workers treating patients with eating disorders. The intention of the programme was partly to increase the knowledge and ability of the participants themselves, and partly to spread this knowledge to other health workers not directly involved in the programme. The programme attracted 66 participants. It was composed of theoretical lectures, group supervision, clinical work with patients with eating disorders and individual supervision as needed. Evaluation at the end of the programme showed a greater feeling of competence and more positive attitudes towards treating these particular patients. More than 80% of the participants had supervised other health workers outside the programme, and nearly 50% had held lectures on the treatment of eating disorders.


[Bulimia nervosa and self-reported symptoms. A questionnaire study among 32 women with bulimia nervosa].

Persons who contacted the Anorexia/Bulimia Association of Norway for information and stated that they had an eating disorder were asked to participate in this questionnaire study. The answers from the 32 women who fulfilled the DSM-III-R criteria for bulimia nervosa are presented. Usually the women's eating problems had started in the teens after a period of voluntary dieting. The mean duration of bulimia nervosa was six years. 31% had a history of anorexia nervosa. At the time of the study almost all had normal body weight, but nevertheless felt overweight. 78% practised self-induced vomiting, 22% used laxatives and 16% used diuretics to reduce weight. Depressive and anxiety symptoms were common in connection with the overeating episodes, but also more generally, which interfered with everyday life. Somatic symptoms (abdominal pain, diarrhoea, constipation, dyspepsia, headache, dry mouth and eyes, parotid gland swelling, muscular symptoms, fatigue, and oligomenorrhoea) were also common.


[Quality assurance in clinical medicine--from theory to practice].

So far, in Norway, quality assurance methodology has been applied mainly within medical technology, and it is now high time to involve clinical medicine. In order to develop quality assurance as a continuous process in clinical departments there is a need for clinical data programmes. Moreover, leaders of health institutions and departments must make available the necessary funds. Greater efforts must be made to develop quality standards and indicators. Clinicians need to improve their knowledge of quality assurance methods, and develop guidelines for practice, different methods of consensus, medical audits and quality circles. It is proposed that education in quality assurance be included in postgraduate training programmes.


[Quality assurance in a surgical department].

The quality of a given service in a surgical department depends on many factors. Most important are adequate resources, training of the surgeons and nurses and time for follow-up and clinical research. Quality standards should be defined in accordance with the international literature and results should be continuously surveyed to ensure that the agreed goals are met. This article describes various general rules and routines which have been established in our department, as well as the specific systems used to measure the quality of our surgical service in three special fields: Care of patients with tumour mammae, care of patients with gallstone disease, and prospective registration of complications for all gastroenterological patients in our surgical department.


[Quality assurance in an emergency department--what is it?].

To date, the medical profession has worked mainly on the improvement of medical treatment and has concentrated less on the methods used and the information given to patients and colleagues. The different aspects of quality in the daily routines are described, and some of these are used as examples of how a system for quality assurance can be developed. It is important that each department develop its own system of quality assurance adapted to local difficulties and different specialties.


[Knowledge about the attitude to mental disorders. An interview study prior to last autumn's TV-action].

In June 1992 a random sample of 1,191 Norwegians were interviewed about their knowledge concerning mental disorders and psychiatric research, and their attitudes in this connection. The study shows that people tend to underestimate the prevalence of mental illness, and they are less willing to talk freely about a mental disorder in the family than about cancer. People have a relatively good understanding of the aetiology of mental disorders. They are less willing, however, to support psychiatric research financially compared with cancer research.


[Attitude to psychiatric patients. How do people look upon alcoholics, drug addicts and psychiatric patients without addictive problems?].

This study examines the public's attitudes towards the rights of alcoholics, drug addicts and psychiatric patients without addiction problems. Positive and negative statements about these patient groups were presented to 806 Norwegian employees. The public's attitudes are far more restrictive towards alcoholics and drug addicts than towards psychiatric patients without addiction problems. The attitudes towards the latter seem to to be quite tolerant, and not very different from the attitudes concerning the rights of somatic patients. While the views on alcoholics and drug addicts are stereotyped, the attitudes towards psychiatric patients without addiction problems seem to be formed more openly, not necessarily on a group basis. Attitudes of acceptance towards alcoholics and drug addicts are more prevalent among younger than among older people.


[Health education in municipal health services--status 1991].

The organization and level of activity of health education were examined in a national survey among the Norwegian municipal health services in 1991. The results were compared with a similar survey conducted in 1987. In 1991, 32% of the municipalities had local health education committees compared with 24% in 1987, and 59% had budgets for health education (1987: 52%). Compared with 1987, more of the municipalities took part in national health education campaigns, but locally initiated activities had become less common. Health promotion initiatives involving the public as active participants were clearly more common than in 1987. Local health education did not depend on the size of the population or other features of the municipality. However, the level of health promotion planning and budgeting were reflected in the health education activities. Cooperation with non-governmental organizations seemed to be the most crucial factor for municipal health education for primary health personnel.


[Oxygen conserving nasal catheters. Oxymizer pendant].

The Oxymizer pendant consists of a 40 ml pendulating reservoir bag which is connected to the prongs by two tubes. Both reservoir and tubes serve as oxygen reservoirs. We wanted to examine if it was possible to save oxygen by changing from the usual nasal cannula to Oxymizer pendant. 11 patients with hypoxaemia due to chronic obstructive pulmonary disease were examined. We were able to reduce the oxygen requirement by approximately 65% without significant changes in SaO2. All 11 patients evaluated the Oxymizer pendant to be more comfortable than the usual nasal cannula.


[Regional anesthesia in emergency cesarean section. Quality of epidural and spinal anesthesia].

From 1987 to 1989, 97.8% of non-elective caesarean sections at Innherred general hospital were performed under regional anaesthesia (N = 271). A retrospective analysis showed that the mean time from giving the anaesthetic until start of surgery was 28.1 min. with epidural anaesthesia and 12.7 min. with spinal anaesthesia. Mean time was 25.9 and 9.3 min. respectively in cases of suspected asphyxia. In eight women primary anesthesia was unsuccessful; six received further spinal anaesthesia and two general anaesthesia. Regional anaesthesia is considered safe for the purpose, but in cases of serious asphyxia there is some controversy as to whether spinal or general anaesthesia is to be preferred.


[Lovastatin in primary hypercholesterolemia. A Norwegian multicenter study].

266 patients with primary hypercholesterolaemia were followed for 48 weeks at 27 different centres to evaluate the safety, tolerability and effect on plasma lipids of lovastatin ranging from 20 to 80 mg/day. Mean change from baseline after 12 weeks of treatment with lovastatin was -34% (CI:33-35) for total cholesterol, -42% (CI:40-43) for LDL-cholesterol, +14% (CI:12-17) for HDL-cholesterol and -14% (CI:10-18) for triglycerides. Combination therapy with cholestyramine (8-24 g/day) was optional, and was started in 89 patients from week 13. At week 48 only 25% of all patients had obtained the second objective of the study: a total cholesterol value below 5.2 mmol/l. At the same time 60% of all patients had a total cholesterol below 6.2 mmol/l. Four patients dropped out of the study owing to adverse clinical experience. Only three of these events were probably related to lovastatin. Six patients were withdrawn because of adverse laboratory experiences. One patient showed clinical signs of myositis and increase of CK. In severe primary hypercholesterolaemia combination therapy with lovastatin and a resin such as cholestyramine is required to obtain total cholesterol values below 5.2 mmol/l.


[Hyponatremia during therapy of von Willebrand's disease. A life threatening complication after desmopressin (Minitrin) infusion].

We describe a patient with moderate von Willebrand's disease who developed severe hyponatremia during prophylaxis with 1-deamino-8D-arginine vasopressin (desmopressin) to prevent bleeding in connection with surgery. This is a rare complication to desmopressin treatment in adults. Our present policy is to restrict administration of desmopressin to three 12-hourly infusions, to measure serum sodium before and during the treatment period, to determine body weight daily and to restrict administration of fluids.


[Quality assurance of municipal health services].

The article describes what can be done to improve quality in the Norwegian primary health services, seen from the point of view of the municipal health officer. Quality assurance is particularly important in the primary health services for the following reasons: They, i.e. the primary health services constitute a major part of the total health services, and they are unique by being a basic front-line service consisting of many small units. Compared with the rest of the health services, many of the personnel employed at these units are not fully qualified. As a consequence, we argue that setting quality standards and ensuring and improving quality in patient care must be an integrated part of the work of all primary health care personnel. Ensuring quality has been a major issue for the national health authorities in recent years, but has not yet been incorporated as a routine in the services. We give six examples where quality assurance is relevant, with references from research.


[Supervision as quality assurance--examplified on the continuous education in psychiatry].

Regular supervision is now compulsory for all medical specialties. This provides a good opportunity to follow the interns through their entire period of specialization, and could therefore be a good tool for quality assurance. If supervision is to function as quality assurance, firm frameworks will have to be established. The content must cover learning of practical skills and improve possibilities for reflection about one's own work and about ethical choices. The supervisor must be competent to understand the supervision as a pedagogic process, not only as an extension of knowledge nor as a purely control function. The supervisor must be open to mutual evaluation and take the responsibility to evaluate the intern's fitness for the specialty. The psychiatric specialist education is used as an example of the different aspects of supervision.


[Complaints--a source of quality assurance even in primary health care].

In this article we discuss the handling of complaints from consumers of primary health care. We present data from municipalities on the frequency of complaints and the ways of handling them. In primary health care complaints are not handled systematically, and are seldom referred to in internal meetings. We conclude that complaints and other reactions from consumers should be used in quality control in primary health care.


[Treatment of bacterial meningitis in children].

The treatment of children with bacterial meningitis includes many aspects, such as fluid and antibacterial therapy, treatment of convulsions, and prophylactic use of dexamethasone. This report focuses in particular on the prophylactic use of dexamethasone together with cefalosporines in order to reduce inflammation and neurological sequelae in this disease. Probably this approach is now justified in the treatment of meningitis caused by Haemophilus influenzae. Modern principles for fluid therapy and treatment of increased intracranial pressure are also discussed.


[Emergency services in Norway. A questionnaire study].

A questionnaire survey of primary health care emergency services in Norway (1991) covered 71 municipalities organized into 43 regions containing about 15% of the Norwegian population. The large cities are excluded. Long distances to travel and frequent duty periods cause some problems, but not for the majority of the population or doctors who participated in the survey. In several regions, a significant part of the service is covered by locums. Written directives for the services are rare. The availability of the doctor on duty falls short several places, owing to lack of satisfactory routines and the occasional need to accompany a patient to hospital. In more than half the regions communication systems are unsatisfactory and will have to be upgraded. In almost half the regions emergency telephone calls are sometimes answered by staff without a medical background. A code of practice or central regulation are suggested as possible ways of improving the services.


[Information systems for health and social care planning. Information basis and information channels in the municipalities].

The Norwegian Government has started to develop a new system for a better exchange of information between the central and the local authorities when planning health and social services. The plan is to base the system on nationwide collection and delivery of standardized indicators which will signal trends and enable comparisons. Several conclusions from an interview survey indicate that the new information system will not be particularly useful. Local authorities believe that their information is good enough already, and have little confidence in statistics prepared by the central authorities. On the other hand many of them called for more statistics that would enable comparisons between neighbouring municipalities, and several had themselves taken the initiative to collect data on various local needs and activities.


Effect of an anti-HLA class I monoclonal antibody on the antigenic and transcriptional expression of HLA class I genes in U937 cells.

The phenomenon of antigenic modulation was studied in the histiocytic lymphoma line U937. A redistribution of cell surface HLA antigen after incubation of U937 cells with the monomorphic anti-HLA class I monoclonal antibody W6/32 was demonstrated by immunofluorescence analysis. As assessed by hybridization of RNA obtained from W6/32-treated U937 cells with a probe corresponding to the alpha 3 domain of HLA Cw3, prolonged W6/32 incubation (24 to 72 hours) induced a decrease in HLA class I transcript abundance. This decrease was about 25% as compared with untreated control cells. These data indicate that W6/32 incubation can induce changes in HLA class I gene expression not only at the antigenic but also at the transcriptional level. Possible implications for the molecular basis of antigenic modulation are discussed.


HLA structure of the Sardinian population: a haplotype study of 551 families.

A study on the HLA structure of the Sardinian population was carried out on 551 healthy unrelated families representing all of the island districts. Altogether 2202 HLA-A, B, Cw, DR individual haplotypes and 853 different haplotypes were determined. Cavalli-Sforza and Edwards' genetic distance index for the total of 62 tested alleles showed a modest heterogeneity between one district and another (0.09-0.16). The genetic distance between Sardinians and the rest of the Italian population was 0.23 (0.22-0.26) and progressively increased in comparisons with caucasoids (0.26), negroids (0.34) and mongoloids (0.41). Sixty-three two-locus haplotypes with a high positive linkage disequilibrium were observed in our family sample. The percentages of two-locus haplotypes in LD shared with other populations turned out to be 45% with caucasoids, 20% with negroids and 10% with mongoloids. The distribution of the A, B, Cw, DR haplotypes is shown with 673 of them represented only once or twice, and 10 (1.2%) 14-322 times each. Of the latter, 8 are extended haplotypes, 6 of which characterize the Sardinian population. The analysis of our data suggests that the present-day Sardinian population is the result of a superposition of different populations, mainly consisting of caucasoids on a pre-caucasoid paleo-Mediterranean substratum.


Analysis of HLA-DR types of unexplained recurrent spontaneous aborters in the Japanese population by oligonucleotide-DNA typing.

To examine whether unexplained recurrent spontaneous abortion (URSA), defined as 2 or more consecutive spontaneous abortions, is correlated with a particular DR type in the Japanese population, we determined the HLA-DR types of 82 primary aborters and 21 secondary aborters by DNA typing utilizing the polymerase chain reaction (PCR) and hybridization with sequence-specific oligonucleotides (SSOs). The DR gene frequencies of the patient group were compared with those of a normal group at three different levels of DR-definition (27, 13 and 11 DR types). At none of the three levels of comparison was any particular DR type with a frequency differing significantly between the patient and normal groups detected in Japanese URSA patients. Furthermore, we examined whether URSA was correlated with the degree of compatibility of HLA-DR antigen within patients and their husbands. Comparison of the DR compatibility between patients and normal couples was made in two different ways, i.e., comparison of the numbers of couples with mismatches and comparison of the average number of mismatches. For either of these two comparisons, we observed no difference in DR compatibility between patients and normal couples. Our results suggest that URSA is not correlated with any particular DR type and that the condition cannot be explained simply by DR compatibility between husband and wife.


Dendritic cells and cutaneous immune responses to chemical allergens.

This article reviews the role of epidermal Langerhans cells (LC) in the development of cutaneous immune responses to chemical allergens. Following topical exposure to sensitizing chemicals, LC, many of which bear allergen, are induced to migrate from the skin, via the afferent lymphatics, to the draining lymph nodes. The phenotypic and functional changes to which LC are subject during this process and their development into active immunostimulatory cells closely resembling lymphoid dendritic cells is discussed. The migration and maturation of LC following skin sensitization is of critical importance to the effective presentation of chemical allergens to T lymphocytes and the induction of allergic responses. Evidence is reviewed which suggests that these events are initiated and regulated by epidermal cytokines. The conclusion drawn is that an early event during the induction of skin sensitization is the production by keratinocytes of cytokines which stimulate the migration of LC from the skin and which also result in the functional maturation of LC into potent antigen-presenting cells.


Alterations in the morphology and functional activity of bone marrow phagocytes following benzene treatment of mice.

Benzene is a well-established hematotoxin that affects developing leukocytes and erythrocytes as well as bone marrow stromal cells. In the present studies we analyzed the effects of benzene on the morphology and functional activity of bone marrow phagocytes. Male Balb/c mice were treated with benzene (660 mg/kg) once per day for 3 days. Bone marrow cells were then isolated and fractionated by density gradient centrifugation. Using highly sensitive techniques in flow cytometry/cell sorting, we found that we could separate three distinct populations of bone marrow cells that differed with respect to size and density. Monoclonal antibody binding and cell sorting revealed a large, dense population that consisted predominantly of granulocytes, a smaller, less dense population of lymphocytes, and a population of intermediate size and density consisting of mononuclear phagocytes and precursor cells. Differential staining of sorted mononuclear phagocytes revealed that benzene treatment of mice caused a marked increase in the number of mature, morphologically activated macrophages in the bone marrow. Benzene treatment of mice also resulted in enhanced chemotaxis and production of hydrogen peroxide by bone marrow granulocytes and mononuclear phagocytes. In contrast, treatment of mice with the combination of hydroquinone and phenol (50 mg/kg each, 1 x/day, 3 days), two metabolites of benzene, resulted in a significant (p < or = 0.02) depression of granulocyte chemotaxis and had no effect on hydrogen peroxide production by bone marrow phagocytes compared to cells from control animals. Taken together these results demonstrate that benzene causes increased differentiation and/or activation of phagocytes in the bone marrow.


In vitro and in vivo effect of methyl isocyanate on rat liver mitochondrial respiration.

Previous work has shown that irrespective of the route of exposure methyl isocyanate (MIC) caused acute lactic acidosis in rats (Jeevaratnam et al., Arch. Environ. Contam. Toxicol. 19, 314-319, 1990) and the hypoxia was of stagnant type due to tissue hypoperfusion resulting from hypovolemic hypotension in rabbits administered MIC subcutaneously (Jeevarathinam et al., Toxicology 51, 223-240, 1988). The present study was designed to investigate whether MIC could induce histotoxic hyperoxia through its effects on mitochondrial respiration. Male Wistar rats were used for liver mitochondrial and submitochondrial particle (SMP) preparation. Addition of MIC to tightly coupled mitochondria in vitro resulted in stimulation of state 4 respiration, abolition of respiratory control, decrease in ADP/O ratio, and inhibition of state 3 oxidation. The oxidation of NAD(+)-linked substrates (glutamate + malate) was more sensitive (five- to sixfold) to the inhibitory action of MIC than succinate while cytochrome oxidase remained unaffected. MIC induced twofold delay in the onset of anerobiosis, and cytochrome b reduction in SMP with NADH in vitro confirms inhibition of electron transport at complex I region. MIC also stimulated the ATPase activity in tightly coupled mitochondria while lipid peroxidation remained unaffected. As its hydrolysis products, methylamine and N,N'-dimethylurea failed to elicit any change in vitro; these effects reveal that MIC per se acts as an inhibitor of electron transport and a weak uncoupler. Administration of MIC sc at lethal dose caused a similar change only with NAD(+)-linked substrates, reflecting impairment of mitochondrial respiration at complex I region and thereby induction of histotoxic hypoxia in vivo.


Dynamic changes in the distribution of the calcium-activated neutral protease in human red blood cells following cellular insult and altered Ca2+ homeostasis.

Mechanistic studies were conducted to examine the relationship between oxidative membrane protein damage, altered Ca2+ homeostasis, and changes in the levels of plasma membrane-bound Ca(2+)-activated neutral protease, microCANP. Alterations in the levels of plasma membrane-bound microCANP in erythrocytes and hemolysate following cumene hydroperoxide (CHP) insult were monitored using SDS-PAGE and immunoblot analyses. Free radical scavengers, antioxidant and EGTA effects on membrane-bound microCANP levels in CHP-treated cells and hemolysate were also examined. CHP (2 mM) addition to red cells caused a significant decrease/loss in intensity of numerous protein bands in the SDS-PAGE pattern, to include bands 1, 2, 2.1, 4.1, 4.2, and an approximately 60-kDa protein. N-acetylcysteine (20 mM), dithiothreitol (50 mM), and dimethylthiourea (50 mM) diminished CHP-mediated membrane protein damage; in contrast, dimethylfuran (50 mM) exacerbated CHP-mediated membrane protein damage. Dimethylsulfoxide (50 mM) was without significant effect. The free radical scavengers and antioxidants differentially affected membrane-bound microCANP levels largely in parallel with their ability to modulate membrane protein damage. Immunoblot analysis of 1 mM CHP-treated red cells revealed a time-dependent loss of membrane-bound microCANP, with a complete loss of microCANP monitored at 8 hr. Treatment of erythrocytes with CHP also resulted in concentration-dependent alterations in the level of membrane-bound microCANP: at 0.5 or 1.0 mM CHP a decreased level of membrane-bound microCANP was detected relative to control, whereas an increase in the level of bound enzyme was monitored from 2 to 4 mM CHP. CHP addition to hemolysate produced a decrease in membrane-bound microCANP levels comparable to that observed with erythrocytes; addition of the Ca2+ chelator EGTA or Calpain Inhibitor I (N-acetyl-leucyl-leucyl-leucyl-nor-leucinal) to hemolysate effectively inhibited this decrease. In contrast, treatment of erythrocytes with Ca2+ in the presence of the Ca2+ ionophore A23187 resulted in change in the SDS-PAGE protein bands and membrane-bound microCANP levels that were comparable to those produced by CHP. Inclusion of EGTA in this system prevented microCANP binding. These data provide evidence for membrane damage and concomitant dynamic alterations in membrane-bound microCANP levels in the red cell or hemolysate following oxidative insult, and show that this process can be modulated by free radical scavengers and antioxidant, simulated by treating cells with Ca2+ in the presence of ionophore, and inhibited by EGTA or Calpain Inhibitor I.


Use of cholinesterases as pretreatment drugs for the protection of rhesus monkeys against soman toxicity.

Purified fetal bovine serum acetylcholinesterase (FBS AChE) and horse serum butyrylcholinesterase (BChE) were successfully used as single pretreatment drugs for the prevention of pinacolyl methylphosphonofluoridate (soman) toxicity in nonhuman primates. Eight rhesus monkeys, trained to perform Primate Equilibrium Platform (PEP) tasks, were pretreated with FBS AChE or BChE and challenged with a cumulative level of five median lethal doses (LD50) of soman. All ChE-pretreated monkeys survived the soman challenge and showed no symptoms of soman toxicity. A quantitative linear relation was observed between the soman dose and the neutralization of blood ChE. None of the four AChE-pretreated animals showed PEP task decrements, even though administration of soman irreversibly inhibited nearly all of the exogenously administered AChE. In two of four BChE-pretreated animals, a small transient PEP performance decrement occurred when the cumulative soman dose exceeded 4 LD50. Performance decrements observed under BChE protection were modest by the usual standards of organophosphorus compound toxicity. No residual or delayed performance decrements or other untoward effects were observed during 6 weeks of post-exposure testing with either ChE.


An in vitro model for assessing muscle irritation of antibiotics using rat primary cultured skeletal muscle fibers.

This study examined the possibility of using rat primary cultured skeletal muscle fiber to estimate the muscle irritation of antibiotics. The cells were exposed to cefaloridine (CER), cefazolin sodium (CEZ), flomoxef sodium (FMOX), cefamandole sodium (CMD), latamoxef sodium (LMOX), or cefalotin sodium (CET) at concentrations of 0 (control), 31.25, 62.5, 125, and 250 mg/ml in culture medium for 1 hr on Day 11 of culture. Cellular creatine kinase (CK) activity was measured as an indication of cell injury. The concentration of the antibiotic, at which CK activity decreased to 50% of the control (depletion concentration 50%, DC50), was utilized as an index of cytotoxicity. DC50s of CER, CEZ, FMOX, CMD, LMOX, and CET were estimated to be 406.7, 311.1, 211.6, 132.7, 114.2, and 56.5 mg/ml, respectively. There was a good correlation between DC50 obtained in the present in vitro test and the irritation volume in the in vivo test. These results suggest that the in vitro system using rat primary cultured skeletal muscle fibers is a useful alternative model for in vivo rabbit study to evaluate muscle irritation.


Nephrotoxicity of the 1:1 acrolein-glutathione adduct in the rat.

Previous metabolic studies in rats have suggested in vivo formation of the acrolein-glutathione (acrolein-GSH) adduct following administration of the highly reactive alpha, beta-unsaturated aldehyde acrolein. Early studies by several investigators demonstrated that similar compounds such as alpha, beta-unsaturated aldehyde-cysteine adducts have toxic (carcinostatic) activity against Ehrlich ascites tumor cells implanted in mice. The current studies investigated the in vivo toxicity associated with the acrolein-GSH adduct in the male Sprague-Dawley rat. The 1:1 acrolein-GSH adduct was synthesized and characterized by physical-chemical methods. Rats given the acrolein-GSH adduct intravenously at 0.5 or 1 mmol/kg developed nephrotoxicity characterized by glucosuria, proteinuria, elevation in serum urea nitrogen, and gross and histologic changes of the kidney. The toxicity was not affected by pretreatment of rats with pyrazole, an alcohol dehydrogenase inhibitor; disulfiram, an inhibitor of aldehyde dehydrogenases; or probenecid, a renal organic anion transport inhibitor. Administration of a similar but nonaldehydic glutathione conjugate, S-n-propylglutathione, did not result in nephrotoxicity in the rat. The nephrotoxicity induced by the acrolein-GSH adduct was inhibited by acivicin, a gamma-glutamyl-transpeptidase inhibitor. These results indicate that the acrolein-GSH adduct requires processing through the first step of the renal mercapturic acid synthesis pathway to be activated to a toxic species.


Dapsone-induced hemolytic anemia: effect of N-hydroxy dapsone on the sulfhydryl status and membrane proteins of rat erythrocytes.

Dapsone hydroxylamine (DDS-NOH), a known metabolite of dapsone, has recently been shown to be a direct-acting hemotoxin responsible in part for dapsone-induced hemolytic anemia in the rat. The effect of DDS-NOH on the morphology, sulfhydryl status, and membrane skeletal proteins of the rat red cell has been investigated. Exposure of rat red cells to a TC50 of DDS-NOH induced transformation of about 50% of the cells to an extreme echinocyte morphology. Reduced glutathione content of the cells was rapidly lost with concomitant increase in the formation of mixed disulfide between glutathione and the soluble protein of the cell. Oxidized glutathione content of the cells did not increase at any time during exposure to DDS-NOH. Examination of the skeletal membrane proteins by SDS-PAGE indicated that DDS-NOH caused the apparent loss of band 4.2, decrease in peaks 1, 2.1, and 3, and the appearance of new bands at about 16, 27, 40, and 54 kDa. Bands 4.1 and 7 appeared unchanged. Treatment of DDS-NOH altered proteins with dithiothreitol, reversed the protein changes, and indicated that the observed alterations were due to the formation of disulfide-linked adducts between hemoglobin and the various skeletal proteins as well as between hemoglobin monomers. The possible significance of the parallel changes in cell morphology and in membrane skeletal proteins for the premature splenic sequestration of the injured rat red cells is discussed.


Local application of neuropathic organophosphorus compounds to hen sciatic nerve: inhibition of neuropathy target esterase and peripheral neurological impairments.

Diisopropyl phosphorofluoridate (DFP), mipafox, cresylsaligenyl phosphate, and phenylsaligenyl phosphate were applied to a 1.5-cm segment of the common trunk of the sciatic nerve in adult hens. At doses of 18-182 micrograms mipafox and 9-110 micrograms DFP, inhibition of neuropathy target esterase (NTE) for the treated segment was over 80%, whereas for the adjacent distal and proximal segments inhibition was under 40%, 15 min after application. NTE was not affected in the peripheral distal terminations arising from the common sciatic nerve (peroneal branches), contralateral sciatic nerve, brain, and spinal cord. A 24-hr study suggested a displacement of the activity-free region toward more distal segments of the nerve. All animals treated with 55 and 110 micrograms DFP or 110 micrograms mipafox lost a characteristic avian retraction reflex in the treated leg 9-15 days after dosing, suggesting peripheral neurological alterations. Only hens dosed at the maximum dose in both extremities presented alterations in motility (Grade 1 or 2 on a 0-8 scale), suggesting no significant central nervous system alterations. Electron microscopy of peroneal branches showed axon swelling and accumulation of smooth endoplasmic reticulum similar to animals dosed systemically (s.c.) with 1-2 mg/kg DFP. The branches also contained granular and electron-dense materials, as well as some intraaxonal and intramyelinic vacuolization. Clinical effects were not observed in animals protected with a 30 mg/kg (s.c.) dose of phenylmethanesulphonyl fluoride. It is concluded that the peripheral neurological effects of local dosing correlate with the specific modification of NTE in a segment of sciatic nerve and that the axon is a more likely target than the perikaryon or nerve terminal in the triggering mechanism of this axonopathy.


Examination of potential mechanism(s) of metallothionein induction by diethyl maleate.

Diethyl maleate (DEM) is a glutathione-depleting agent that can increase the levels of the sulfhydryl-rich protein metallothionein (MT) in liver. The purpose of the present study was to examine the mechanism(s) by which DEM increases mouse hepatic MT levels. DEM appears to be an indirect MT inducer as suggested by the lack of increase in MT levels when cultured mouse hepatocytes were exposed to DEM. Four possible mechanisms by which indirect MT inducers may cause an elevation in MT concentrations in liver were examined. Zn levels did not increase prior to the increase in hepatic MT, thus, a Zn redistribution to the liver is not the cause of the liver MT induction by DEM. The adrenal gland products were not required for MT induction in liver, as adrenalectomy did not abolish the increase in hepatic MT caused by DEM. The elevation in liver MT does not appear to be due solely to the decrease in liver glutathione (60%) in the initial hour after DEM, because phorone, which decreases liver glutathione (80%), produced only a fourfold increase in hepatic MT. Activation of macrophages does not seem to account for the rise in liver MT levels, as there was no increase in abundance of cytokine mRNAs for TNF-alpha, IL-1 beta, or IL-6 in the liver. These data suggest that the induction of hepatic MT by DEM does not occur in response to (1) an increase in liver Zn that precedes the increase in liver MT, (2) release of adrenal gland products, (3) decrease in liver glutathione, or (4) increased cytokine gene expression.


Induction of hepatic metallothionein by paraquat.

Paraquat, a frequently used contact herbicide, produces oxidative stress by undergoing redox cycling and generating reactive oxygen species. Paraquat is also effective at increasing hepatic levels of metallothionein (MT). The mechanism(s) by which agents that induce oxidative stress produce increases in MT concentrations is not yet known. Therefore, the goal of the current study was to characterize the elevation in hepatic MT produced by paraquat administration to mice and to examine potential mechanism(s) of this increase. A dose-response study for increases in MT showed that administration of 0.1 to 0.5 mmol/kg of paraquat, sc, increased hepatic MT with a maximal increase of 36-fold. Subsequent studies were carried out with paraquat at a dose (0.3 mmol/kg, sc) that caused oxidative stress, as shown by a 35-fold increase in the biliary excretion of oxidized glutathione. There were coordinate elevations of both hepatic MT-I and MT-II mRNA of approximately 5-fold with peaks at both 6 and 24 hr after paraquat. The time course for the elevation in hepatic MT protein following paraquat treatment showed that MT levels had a maximal increase of 18-fold obtained at 36 hr. Paraquat appears to be an indirect MT inducer, in that there were no elevations in MT when cultured mouse hepatocytes were exposed to paraquat. No rise in liver Zn was observed prior to the increase in hepatic MT, thus, a Zn redistribution to the liver did not cause the increase in hepatic MT following paraquat administration. Adrenalectomy did not abolish the increase in MT produced by paraquat, suggesting that adrenal gland products are not required for the increase in MT produced by paraquat. In conclusion, the chemical mediator responsible for the increase in hepatic MT after paraquat was not determined, but the elevation in MT concentration appears to be due to increased transcription.


Accumulation and degradation of the protein moiety of cadmium-metallothionein (CdMT) in the mouse kidney.

Of major concern in Cd toxicity is its ability to produce renal damage after chronic exposure in humans and experimental animals. Renal injury affects predominantly the proximal tubules and more specifically the first segments of these tubules. Similar toxic effects to the kidneys are observed after administration of cadmium bound to metallothionein (CdMT). Therefore, CdMT was used in this study as a model to understand the mechanism(s) of Cd nephrotoxicity. It has been recently demonstrated that Cd from CdMT was preferentially taken up by the proximal convoluted tubules. Therefore, the purpose of these studies was to determine if the organic portion of the complex was also accumulated in these tubules. [35S]CdMT prepared from rat liver was administered intravenously to mice at a nonnephrotoxic dose (0.1 mg Cd/kg). The radioactivity in the kidney showed maximum level (80% of the dose) 15 min after the injection. This preferential renal uptake was also observed after administration of various doses of [35S]CdMT. In contrast to the earlier observed persistency of 109Cd in the kidney after 109CdMT administration, 35S disappeared rapidly (with a half-life of approximately 2 hr), and 24 hr after injection of [35S]CdMT, there was very little 35S left in the kidneys. These observations indicate that the protein portion of CdMT is rapidly degraded after renal uptake of CdMT and the released Cd is retained in the kidney. Within the kidney, 35S distributed mainly to the cortex. Light microscopic autoradiography showed that [35S]CdMT preferentially distributed to the proximal convoluted tubule (S1 and S2), which is the site of nephrotoxicity. Within the S1 and S2 segments, a greater distribution of 35S to the apical portion of the cells was observed after administration of both a nonnephrotoxic (0.1 mg Cd/kg) and a nephrotoxic (0.3 mg Cd/kg) dose. 109Cd administered as 109CdMT also distributed to the apical portion of the S1 and S2 cells. Therefore, both the organic (35S) and inorganic (109Cd) portions of CdMT are rapidly and efficiently taken up by the S1 and S2 cells of the proximal tubules, the site of nephrotoxicity. These observations support the concept that CdMT is readily taken up by the proximal tubular cells as a complex, and then its protein portion is rapidly degraded to release Cd that binds permanently to intracellular sites and produces nephrotoxicity.


A putative lectin-binding receptor mediates cadmium-evoked calcium release.

Nanomolar concentrations of cadmium (Cd2+) produce an immediate rise in free Ca2+ in human dermal fibroblasts, which is mostly caused by the release of stored Ca2+ via inositol trisphosphate. Here we have used lectins to evaluate the hypothesis that a cell surface glycoprotein mediates the response to Cd2+. A prior incubation with wheat germ agglutinin (WGA) or certain other lectins inhibited calcium release evoked by Cd2+. WGA reversibly inhibited Cd(2+)-evoked calcium release as indicated by measurements of cytosolic free Ca2+ and 45Ca2+ efflux. WGA half-maximally inhibited Ca2+ release at 1.2 x 10(-7) M. The Kd for the binding of fluoresceinylated WGA was 2.8 x 10(-7) M. Chitotriose dissociated fluoresceinylated WGA from the cells and restored cadmium responsiveness. WGA inhibited Cd(2+)-evoked 45Ca2+ efflux similarly at 18 and 37 degrees C. A brief incubation with chitotriose at 18 or 10 degrees C reversed the inhibition by WGA. WGA neither bound 109Cd2+ nor affected 109Cd2+ uptake by the cells. Succinylated WGA, which binds N-acetylglucosamine but not N-acetylneuraminic acid, failed to inhibit Ca2+ release evoked by Cd2+. WGA probably inhibits Ca2+ release produced by Cd2+ by binding to N-acetylneuraminic acid in the external domain of a plasma membrane receptor.


Incorporation of [35S]sulfate into glomerular membranes of rats chronically exposed to cadmium and its relation with urinary glycosaminoglycans and proteinuria.

The aim of the present work was to assess the effects of long-term exposure to Cd on the sulfatation of glomerular membranes and their relation with proteinuria and urinary glycosaminoglycans (GAG). For this purpose the in vitro incorporation of [35S]sulfate was investigated in female Sprague-Dawley rats given 100 ppm of Cd in drinking water for 7 months. When compared with their controls, glomeruli from Cd-treated rats showed a 12.8% decrease in the incorporation of the label into glomerular membranes. This effect, which was not explained by differences in viability or in sulfate uptake by the glomeruli, suggests that sulfatation of glomerular membranes is impaired in Cd-treated rats. In support of this, in another independent experiment, a decrease, 17.4% on average, of the sulfate content of glomerular membranes was observed in long-term Cd-treated rats (100 ppm in drinking water for 4 months). This effect was significantly correlated with albuminuria and transferrinuria but not with beta 2-microglobinuria, suggesting that a loss of heparan sulfate of the glomerular capillary wall could be involved in the Cd-induced glomerular proteinuria. On the other hand an enhanced urinary excretion of GAG, negatively correlated with the sulfate content of glomerular membranes, was also observed in Cd-treated rats. Moreover GAG excretion was associated with tubular and glomerular proteinuria, which suggests that GAG might be a useful marker of Cd-induced nephrotoxicity.


Isolation and structure determination of natural analogues of the mycotoxin ochratoxin A produced by Aspergillus ochraceus.

Three new natural mycotoxins, analogues of ochratoxin A, in which the phenylalanine moiety is replaced by serine, hydroxyproline or lysine, were isolated from cultures of Aspergillus ochraceus by TLC followed by HPLC column chromatography. Their structures were determined after acidic hydrolysis by the characterisation of both their amino acid moieties and of ochratoxin alpha, the chlorinated dihydroisocoumarin moiety of ochratoxin A. These structures were confirmed by mass spectrum analysis.


Differences of draining lymph node cell proliferation among mice, rats and guinea pigs following exposure to metal allergens.

Contact sensitivities of three well known metal allergens (nickel sulfate, potassium dichromate and cobalt chloride) were examined using the local lymph node assay in CBA/N mice, F344 rats and Hartley guinea pigs. The effect of various species sera on lymph node cell (LNC) proliferation was also investigated. Exposure to potassium dichromate and cobalt chloride induced significant LNC proliferative responses in the three species. The LNC responses to potassium dichromate in the rats were higher than those in the mice and guinea pigs. Mice exhibited the highest response to cobalt chloride among the three species, whereas, exposure to nickel sulfate failed to induce a marked LNC proliferation. Increased draining lymph node weights and LNC numbers were also observed following exposure to the metal salts. However, these parameters were less sensitive compared with the LNC proliferative response. There was a large difference in the lymph node weight between individual guinea pigs. The [methyl-3H]thymidine incorporation into LNC of each species cultured in the presence of the homologous serum in vitro was lower than in the presence or absence of fetal calf serum. However, there was no significant difference in stimulation indices among the different culture conditions. The local lymph node assay may be performed in rats as well as in mice for the detection of metal allergens.


Cholesterol and mevalonic acid modulation in cell metabolism and multiplication.

Cholesterol in animals is a major structural component of cell membranes. It may therefore play a functional role in the modulation of cell osmolarity, the process of pinocytosis and the activities of membrane-associated proteins such as ionic pumps, immune responses, etc. A major relationship exists between the cell-growth processes and the cholesterol biosynthetic pathway. The cholesterol needed for new membranes may be derived either from endogenous synthesis or from exogenous sources, principally plasma low-density-lipoproteins (LDL) which enter the cells by receptor-mediated endocytosis. Both these pathways are enhanced in rapidly growing cells. Conversely, if synthesis is inhibited and no exogenous cholesterol is available, cell growth is blocked. The 3-hydroxy-3-methylglutaryl CoA (HMGCoA) reductase (the rate-limiting reaction in cholesterol biosynthesis) is the enzyme which catalyzes the conversion of HMGCoA to mevalonic acid. It has been suggested that mevalonate may play an important role in cell proliferation. All cells need at least two products synthesized from mevalonate in order to proliferate, and the only one yet identified is cholesterol. Other melavonate-derived potential candidates as cell-cycle and cell-survival products include the dolichols ubiquinone side chains, isopentenyladenosine derivatives, etc. Furthermore, it has recently been shown that membrane association appears to be an important function in mevalonate-derive modifications of several important proteins such as cellular membrane G proteins, those coded for by oncogenes (ras proteins) and lamins (nuclear proteins). In recent years the development of cholesterol-synthesis-inhibiting drugs, for lowering plasma cholesterol levels has mainly been centred on the control of HMGCoA reductase activity (vastatins). However, because mevalonic acid is the precursor of numerous metabolites, any reduction of such activity may potentiate pleiotropic effects. Vastatins are now, therefore, receiving increased attention as potential pharmacological tools for the control of abnormal cell growth in pathological situations, i.e. tumours and vascular smooth muscle cell proliferation under atherogenic conditions. In our laboratories, we have demonstrated that simvastatin can prevent arterial myocyte proliferation both in vivo and in vitro. Simvastatin can also inhibit in vitro the rate of human glioma cell growth, since it shows a strong synergistic inhibitory effect on cell proliferation when used in association with anticancer agents such as Carmustine or beta-interferon. Both simvastatin-induced cell growth inhibition and the synergy observed with these drugs can be completely reversed by incubating cells with mevalonate. This shows that the effect of simvastatin of cell proliferation is due to its specific inhibitory activity on intracellular mevalonate synthesis.


The popliteal lymph node assay: a tool for studying the mechanisms of drug-induced autoimmune disorders.

Whereas it is still impossible to predict the risk for organ-specific drug-induced autoimmune disorders in animals, a large body of evidence suggests that the popliteal lymph node assay (PLNA) in mice or rats is instrumental to predict systemic drug-induced autoimmune disorders. Metabolites may be involved instead of the parent molecules in a few instances as shown by studies using animals pretreated with enzyme inducers. Histological examination can help distinguish primary irritants, contact sensitizers and 'autoimmunogenic' compounds. That a Graft-vs-Host (GvH)-like mechanism may be involved was further substantiated by the finding that histological features of a positive PLNA response to, e.g. streptozotocin, were quite similar to those of a 'true' local GvH response. In addition, this model is expected to be useful to improve our understanding of the mechanism(s) involved in systemic autoimmune reactions by studying the profile of PLN lymphocyte subpopulations and of released cytokines.


Molecular basis for differences in susceptibility to toxicants: introduction.

Many toxicants depend upon metabolism for their elimination and/or conversion to the toxic species. As a consequence, differences in metabolism can have a profound influence on interspecies and interindividual susceptibility to toxicity. Until relatively recently, the molecular basis for such differences were not known. However, over the past decade and a half, our understanding of the factors controlling the expression and regulation of the enzymes of drug metabolism has increased dramatically. Thus, the molecular basis of the common polymorphisms of drug metabolism in man, in CYP2D6 (debrisoquine 4-hydroxylase) and NAT2 (arylamine N-acetyltransferase) has been determined, and considerable progress has been made in elucidating the regulatory control of inducible enzymes such as CYP1A1 and CYP4A1. The number of drug metabolising enzymes subject to genetic polymorphism in man is not known, but rare genetic differences in enzymes such as epoxide hydrolase are increasingly being implicated in susceptibility to toxicants previously attributed to idiosyncrasy Indeed, the whole concept of idiosyncrasy in reactions to toxicants is being rendered obsolete by such advances. As information on the basis of differences in susceptibility accrues, the challenge is to apply this knowledge in identifying the "at risk" population. Although much progress has been made in this area, there are still many unanswered questions. What controls the tissue, and indeed cell, selective expression of some enzymes of drug metabolism? What is the molecular basis of species differences in specificity? And most importantly, what factors beyond metabolism are involved in determining susceptibility, and how do these interact with differences in metabolism?


Genetically determined differences in drug metabolism as a risk factor in drug toxicity.

Drug metabolizing enzymes are of paramount importance in drug detoxification as well as chemical mutagenesis, carcinogenesis and toxicity via metabolic activation. Thus genetically determined differences in the activity of these enzymes can influence individual susceptibility to adverse drug reactions, drug induced diseases and certain types of chemically induced cancers. The genetic polymorphisms of three human drug metabolizing enzymes, namely N-acetyltransferase and two cytochrome P-450 isozymes (P-4502D6: debrisoquine/sparteine polymorphism, P-4502C8-10: mephenytoin polymorphism) have been firmly established. Based on the metabolic handling of certain probe drugs, the population can be divided into two phenotypes: the rapid acetylator/extensive metabolizer and slow acetylator/poor metabolizer. These polymorphisms have provided useful tools to study the relationship between genetically determined differences in the activity of drug metabolizing enzymes and the risk for adverse drug reactions and certain types of chemically-induced diseases and cancers. With regard to the susceptibility of the two phenotypes, drug mediated toxicity for the following scenarios can be anticipated. (1) The toxicity of the drug is caused by the parent compound and the elimination of the drug proceeds exclusively via the polymorphic enzyme. No alternate pathways of biotransformation are available. Thus the slow acetylator/poor metabolizer phenotype will be more prone to such a type of toxicity since, at the same level of exposure, this phenotype will accumulate the drug as a result of impaired metabolism (e.g. isoniazid polyneuropathy, perhexiline polyneuropathy, pesticide induced Parkinsons disease). (2) The polymorphic pathway is a major route of detoxification. Impairment of this pathway shifts the metabolism to an alternate pathway via which a reactive intermediate is being formed. In such a situation the slow acetylator/poor metabolizer phenotype constitutes a major risk factor for toxicity (e.g. isoniazid hepatotoxicity). (3) The toxicity is mediated by a reactive intermediate generated by a polymorphic enzyme. Hence extensive metabolizers are at a much higher risk than poor metabolizers to develop toxicity or cancer (e.g. bronchial carcinoma in smokers, not chemically induced aggressive bladder cancer).


Acetyltransferases and susceptibility to chemicals.

Arylamine chemicals inflict a number of toxicities including cancer. Metabolic activation (i.e., oxidation) is required in order to elicit the toxic actions. Acetylation is an important step in the metabolic activation and deactivation of arylamines. N-acetylation forms the amide derivative which is often nontoxic. However, O-acetylation of the N-hydroxyarylamine (following oxidation) yields an acetoxy arylamine derivative which breaks down spontaneously to a highly reactive arylnitrenium ion, the ultimate metabolite responsible for mutagenic and carcinogenic lesions. Human capacity to acetylate arylamine chemicals is subject to a genetic polymorphism. Individuals segregate into rapid, intermediate, or slow acetylator phenotypes by Mendelian inheritance regulated by a single gene encoding for a polymorphic acetyltransferase isozyme (NAT2). Individuals homozygous for mutant alleles are deficient in the polymorphic acetyltransferase and are slow acetylators. A second acetyltransferase isozyme (NAT1) is monomorphic and is not regulated by the acetylator genotype. Several human epidemiological studies suggest an association between slow acetylator phenotype and urinary bladder cancer. In contrast, a few studies suggest a relationship between rapid acetylator phenotype and colorectal cancer. The basis for this paradox may relate to the relative importance of N- versus O-acetylation in the etiology of these cancers. Conclusions drawn from human epidemiological data are often compromised by uncontrolled environmental and other genetic factors. Our laboratory recently completed construction of homozygous rapid, heterozygous intermediate, and homozygous slow acetylator congenic Syrian hamsters to be homologous in greater than 99.975% of their genomes. The availability of these acetylator congenic lines should eliminate genetic variability in virtually all aspects of arylamine carcinogenesis except at the acetylator gene locus. Ongoing studies in these congenic hamster lines should provide unequivocal information regarding the role of genetic acetylator phenotype in susceptibility to arylamine-related cancers.


Inherited defects in DNA repair and susceptibility to DNA-damaging agents.

Since all organisms are continuously exposed to exogenous and endogenous DNA damaging agents, mechanisms of repair of DNA lesions are necessary to maintain the integrity of the genome. Studies of the cellular defects in human inherited diseases with deficiencies in DNA repair have given new insights into these processes. Nucleotide excision repair is an important DNA repair pathway in which several types of DNA lesions are removed by a multi-step enzymatic process. This repair mechanism is deficient in the rare disease xeroderma pigmentosum (XP), which results in extreme sensitivity to ultraviolet light (UV) and development of UV-induced skin tumors at an early age. There are several genetic complementation groups of XP. The genes that are mutated in some of the XP complementation groups have been cloned and the functions of the encoded proteins are being characterised. Several types of DNA lesions are removed more rapidly from active genes than from other regions of DNA. This preferential repair of active genes is deficient in Cockayne's syndrome, which is characterised by developmental abnormalities and UV-sensitivity but no marked increase in cancer incidence. Other syndromes associated with increased sensitivity to certain DNA damaging agents where no defect in DNA repair has been defined include Fanconi's anemia (sensitivity to DNA cross-linking agents), hereditary dysplastic nevus syndrome (sensitivity to UV) and ataxia-telangiectasia (sensitivity to ionizing radiation).


Are newer scientific concepts in regulatory toxicology used timely and appropriately?

Laws regulating toxicology (e.g. toxic thresholds allowed, poison classes or definition of necessary preclinical testing) might improve health and save lives. Scientific facts will always serve as a mandatory base for political decision-making, but there will also be additional influences (perception and acceptance of risks, possible benefits, economic considerations etc.). These latter factors may vary considerably from one society to another. The Delaney clause prohibited the marketing of any product which was found to be carcinogenic in animals. Due to their benefits, exceptions were made for drugs. In other countries, too, other chemicals could be an exception due to a different perception of the risk or different scientific evaluation. Clear cases of major events always trigger changes in legislation. When in 1937 a newly-marketed sulfanilamide elixir led to severe kidney damage and 70 deaths, the FDA quickly endorsed the propositions of the investigation team set up by the American Medical Association: animal testing in two species with histopathologic examination before a marketing authorization could be granted became mandatory. A similarly rapid reaction followed in Europe when it was detected that Thalidomide was responsible for malformations in the offspring of mothers who had taken the drug in early pregnancy. When the effects are more difficult to link to a chemical, there may be time delays in regulatory actions. However, a sophisticated evaluation system was introduced for better monitoring of drug and chemical hazards. Some examples will be given in order to discuss the difficulties of timely and appropriate use of scientific findings.


New approaches to the assessment of eye and skin irritation.

Assessment of eye and skin irritation potential is an important part of any comprehensive toxicology programme for new chemicals and consumer products. The original skin and eye irritation assessment methods described by Draize et al. are still widely used for regulatory purposes with only slight modification. These methods have been re-evaluated in the light of the modern approach to toxicological testing requiring refinement of protocols, reduction in animal numbers, and replacement of in vivo tests by in vitro assays. A refinement in the original Draize skin irritation test accepted by regulatory authorities is reduction of test substance exposure time from 24 to 4 h. This makes the test less stressful. The Low Volume Eye Irritation Test is also a less stressful, more predictive refinement of the Draize eye irritation procedure. Many in vitro models are being developed for use in the assessment of eye and skin irritation potential in the hope that the animal tests may some day be replaced. In order for alternative tests to be incorporated into safety assessment, they must undergo a defined evaluation that allows toxicologists to determine whether the new procedures provide relevant information. As the validity of the methods is determined, the new procedures can be incorporated into safety assessment using a tier assessment process. The first step in tier testing is a thorough analysis of existing in-house and published data on the test substance or similar material. A review of physical/chemical characteristics can also provide valuable information. If more data are needed in order to complete the safety assessment, the next step is to evaluate the test substance in in vitro assays. The in vitro data may provide sufficient information to make a safety assessment. If additional information is required, then in vivo testing may be conducted using a limited number of animals or human clinical studies. If alternative procedures are to be ultimately accepted for use in safety assessment, regulatory authorities must become active participants in programmes designed to assess and validate the new tests.


Classification of chemicals as sensitisers based on new test methods.

For the last decade, classification schemes worldwide have recognised that certain chemicals may need to be categorised as skin or respiratory sensitisers. Although differing in detail, the schemes use similar criteria for designating materials as sensitisers, based on either direct evidence from exposed humans or the results of predictive guinea pig tests. In the case of respiratory sensitisation, however, there are currently no acceptable animal test methods. With an increasing understanding of cellular immunology in general, and of immune responses in skin and respiratory sensitisation in particular, several laboratories have recently been developing more objective, immunologically-based tests. For skin sensitisation, the two most promising methods are the murine local lymph node assay (LLNA) and the mouse ear swelling test (MEST). Both assays have undergone inter-laboratory validation and it has been shown that they are able to detect reliably moderate to strong sensitisers. The 1992 update of the OECD test guideline for skin sensitisation suggests the use of the LLNA or MEST as a first stage of testing; if a positive result is seen in either assay, a chemical may then be designated (and classified) as a potential sensitiser and it may not be necessary to conduct a guinea pig test. However, if a negative result is obtained, a guinea pig test must be performed. For respiratory sensitisation, although certain guinea pig models of asthma appear to be predictive of the known human response to sensitisers such as diisocyanates and acid anhydrides, the measurement of changes in serum IgE antibodies in mice treated topically with chemicals may represent a simpler and more accurate method of designating chemicals as respiratory sensitisers.