[Laboratory diagnosis of cobalamin deficiency. A comparative study of 2 serum cobalamin methods and serum methylmalonic acid]

The diagnosis of cobalamin deficiency is established traditionally by demonstration of lowered serum cobalamin, but, for many reasons it cannot be anticipated that the concentrations of cobalamins in the serum reflect the relationship between blood cobalamin and tissue cobalamin accurately. The blood methylmalonic acid which cannot be metabolized in cases of cellular cobalamin deficiency should, on the other hand, indicate the cobalamin available for the tissues. A blind, prospective, controlled investigation was undertaken to compare the clinical employability of a recently developed method for measurement of the concentration of methylmalonic acid in the serum with older and more recent methods of measuring serum cobalamins. The three methods classified 94, 72 and 74% of the patients correctly, respectively (n = 50). The results reveal that serum methylmalonic acid is a more sensitive and specific analysis for demonstrating whether cobalamin deficiency was present or not. Serum cobalamins measured by both methods are relatively insensitive and unspecific markers for cobalamin deficiency in the tissue. Low cobalamin concentrations do not indicate that the patient in question has cobalamin deficiency, and values in the lower half of the reference interval do not exclude cobalamin deficiency. Measurement of methylmalonic acid in the serum is recommended in patients with low-normal or low serum cobalamin.

[Determination of vitamin b12 deficiency]

Development of cobalamin deficiency in the tissues is considered to be a process which lasts for years. Macrocytic anaemia and/or neurological symptoms do not occur until late in this process. Serum cobalamins as the only parameter have proved less suitable for differentiation between healthy individuals with low serum cobalamin values and patients who require cobalamin for the remainder of their lives. The need for a better indicator for cobalamin deficiency has been emphasized. Recently developed methods of measurement have rendered determinations of serum methylmalonic acid possible. This value is raised in cases of cobalamin deficiency in the tissues. The serum methylmalonic values have proved both sensitive and specific to determine the extent to which genuine cobalamin deficiency is present or not and may also be employed for monitoring the effect of treatment as the raised values becomes normalized following substitution therapy with vitamin B12.

[Cobalamin deficiency despite normal serum cobalamins]

In a man aged 77 years with normal concentrations of cobalamins in the serum, the concentration of methylmalonic acid in the serum was raised (2,920 nmol/l; 50-370 nmol/l). (The serum cobalamin concentrations were measured both by an old R-binder method (400 pmol/l; reference interval 200-800 pmol/l) and by a more recent S-binder method (164 pmol/l; 95-585 pmol/l)). Following a saturation dose of vitamin B12, the serum concentration of methylmalonic acid became normal (215 nmol/l) indicating that the patient had had functional cobalamin deficiency. The clinician should never let himself be deceived by a normal concentration of cobalamins in the serum and thus discard a suspicion of cobalamin deficiency. Measurement of serum methyl-malonic acid, which is a sensitive and specific analysis to differentiate between the presence or absence of cobalamin deficiency, is recommended to elucidate cases of doubt.

Non-invasive quantitative measurement of blood flow and estimation of vascular resistance by the Doppler ultrasound method. Methodological studies and clinical application on the fetus and the transplanted kidney allograft

The introduction of ultrasound 25 years ago was an important improvement and represented a significant step forward in the examination of several organs, especially in the abdomen. During the last 10 years it has been possible to combine Real-Time ultrasound with Doppler ultrasound, thus gaining information on the blood flow and vascular resistance in several organs. The ultrasound method has great advantages; it is non-invasive, can be repeated whenever needed, can be performed bed-side and is inexpensive to use. The present study was undertaken to examine whether the method could be used to diagnose several pathological conditions relevant to the obstetrician and the nephrologist. Before clinical application was performed, the theories behind the ultrasound Doppler principle and the possibilities and limitations of the equipment available for examinations were carefully examined and the method was improved in several important aspects. The precision and accuracy of the improved method was tested in-vitro and in-vivo studies. It was shown that the ultrasound Doppler method has now been developed to an acceptable degree of precision and accuracy for use in scientific investigations and daily clinical routine. The method was then used to examine the fetal and the renal allograft hemodynamics. Reference values for quantitative blood flow in the fetal aorta and the umbilical vein, and for vascular resistance in the normal fetus and the renal allograft were provided, and the method was used to describe hemodynamic changes during several pathological conditions. Some hitherto unknown physiological and pathophysiological variations of blood flow and vascular resistance were found. Thus it was demonstrated that fetal hemodynamics are affected during untreated maternal hypertension in pregnancy and changed towards normal during treatment of the mother, and that renal vascular resistance is increased during rejection of the allograft and normalized following treatment. Furthermore, it was demonstrated that the ultrasound Doppler examination is of diagnostic value when dysfunction of the renal allograft is present.

Coordinate Regulation of the Cyclic AMP System with Firing Rate and Expression of Tyrosine Hydroxylase in the Rat Locus Coeruleus: Effects of Chronic Stress and Drug Treatments

Recent studies have demonstrated that chronic stress increases the firing rate and expression of tyrosine hydroxylase (TH) in neurons of the locus coeruleus (LC), the major noradrenergic nucleus in brain. The present study was undertaken to examine the influence of chronic stress and other treatments known to influence the activity of LC neurons on the cyclic AMP (cAMP) second messenger system in these neurons. Chronic (5 days) cold exposure significantly increased levels of TH immunoreactivity in the LC, as previously reported, but not in substantia nigra (SN) or ventral tegmentum (VT), two dopaminergic nuclei studied for comparison. Chronic cold exposure increased levels of cAMP-dependent protein kinase activity in soluble, but not particulate, fractions of the LC, and increased basal and GTP- and forskolin-stimulated adenylate cyclase activity in this brain region. In contrast, levels of the protein kinase and adenylate cyclase in VT, SN, and frontal cortex were not significantly influenced by cold exposure. To study further the relationship between regulation of LC firing rate, TH expression, and the cAMP system in the LC, other treatments known to influence TH were examined. Reserpine treatment, shown previously to increase levels of TH, was found to increase both LC firing rate and levels of soluble cAMP-dependent protein kinase activity in the LC. 6-Hydroxydopamine, shown previously to increase levels of TH and firing rate of LC neurons, also increased soluble levels of protein kinase activity. Other treatments known to either increase (adrenalectomy) or decrease (chronic imipramine) levels of TH in the LC were also found to increase or decrease, respectively, levels of cAMP-dependent protein kinase activity in this brain region.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholecystokinin (CCK) and schizophrenia: the selective CCKB antagonist LY262691 decreases midbrain dopamine unit activity

Chronic administration of antipsychotic drugs has previously been shown to decrease the number of spontaneously active midbrain dopamine cells. In an effort to evaluate CCK antagonists as potential antipsychotic drugs, we have examined the effects of a selective CCK-B antagonist, LY262691, on the number of spontaneously active midbrain dopamine neurons using extracellular, single-unit recordings in anesthetized rats. Acute and chronic administration of LY262691 decreased the number of spontaneously active A9 and A10 dopamine cells. Administration of apomorphine did not reverse the effect of LY262691 on A9 and A10 dopamine neurons. These results suggest that LY262691 may have an antipsychotic effect without delayed onset, and that its effects on dopamine cells may not be mediated through depolarization inactivation.

Treatment of Parkinson's disease with electroconvulsive therapy

There is substantial evidence that electroconvulsive therapy (ECT) can ameliorate the symptoms of Parkinson's disease independent of any antidepressant activity. ECT thus presents a treatment alternative for the severely impaired, medication-resistant Parkinson's patient. In this article, we review the literature on this subject and present our recommendations for current clinical practice.

The 5-HT3 receptor antagonist zatosetron decreases the number of spontaneously active A10 dopamine neurons

Acute and chronic administration of low doses (e.g. 0.1, 0.3 mg/kg i.p.) of the selective 5-HT3 antagonist zatosetron decreased the number of spontaneously active A 10 dopamine cells but did not change the number of spontaneously active A9 dopamine cells; higher doses (1.0, 10 mg/kg) were less effective. The decrease in the number of spontaneously active A 10 dopamine cells following zatosetron administration was not reversed by the administration of apomorphine. These data indicate that zatosetron's effects on spontaneously active dopamine neurons: (1) differs from other 5-HT3 antagonists; (2) may not be mediated by depolarization inactivation; and, (3) may be predictive of an atypical antipsychotic action without delayed onset.

Effects of lymphocyte activation on transfer RNAs

The influences of mitogen activation on the functional capacity of rat splenic tRNAs were evaluated. The specific amino acid acceptor activity, pmol of a specific amino acid accepted per nmol of tRNA, of isolated splenic tRNAs from in vivo Concanavalin A (37 h)-treated rats were up to 8 times the specific amino acid acceptor activities of splenic tRNAs from control rats. Control splenic tRNAs were treated with purified liver tRNA nucleotidyltransferase in vitro to repair the 3'[CCA] terminus of tRNAs, and subsequently assayed in an aminoacylation reaction. The specific amino acid acceptor activities were slightly increased over those tRNAs not repaired with tRNA nucleotidyltransferase, indicating the presence of a low level of defective but repairable tRNAs in the control rat spleen. Furthermore, our results indicate that cyclosporin A (inhibitor of lymphocyte activation) blocks the Concanavalin A stimulation of tRNA charging ranging from 16 to 93%.

Biological monitoring and medical screening at the workplace in the EC countries

Health surveillance in the work environment involves continuous biological monitoring and medical screening, with the purpose of primary and secondary prophylaxis of work-related diseases. Is this screening activity governed by a rationale based on knowledge of dangerous exposure and the availability of valid tests? In the USA, where health surveillance programmes are used extensively, a study has found screening activity to be associated more with plant size than which relevant exposure. This study was done to elucidate the character and extent of use of health surveillance in the work environment in the EC countries with the aid of a questionnaire survey. The chief medical officers of the National Labour Inspectorates supplied information on substances covered by health surveillance programme in the EC member states, together with the legislative status and numbers of exposed workers. Belgium, France, Italy and the former Federal Republic of Germany made extensive use of health surveillance programmes in cases of known exposure to metals, organic solvents, carcinogenic and genotoxic substances, mineral dust, ionizing radiation, and biological agents. Denmark and Holland ran national programmes only for substances covered by EC directives, while England, Ireland, Spain, and Portugal comprised an intermediate user group. The result suggest that the use of health surveillance is related more to the national choice of standard regulatory instruments than to relevant exposure.

[The significance of brain death as a criterion for renal transplantation. Status after 9 months]

The effect of introduction of the brain-death criterion in Denmark on the course of cadaver kidney transplantation was evaluated by comparing the course of 31 consecutive patients transplanted after introduction of brain-death criterion with the course of a similar consecutive group of patients transplanted just before the new death criterion. The consequences of the new death criterion were significantly earlier onset of graft function, diminished need for posttransplant dialyses, reduced need for immunosuppressive treatment with Minnesota-antilymphocytglobulin and briefer hospital stays. The easier postoperative course had great psychological effects for the patients and the staff, and the cost of each transplantation was estimated to be reduced by at least 50,000 DKr per patient (approximately 5,000 pounds).

[Assessment of the health risk of a residential area contaminated with arsenic and lead. Biological monitoring in Mundelstrup]

Industrial use of toxic substances has resulted in contamination of the outer environment so that polluted area now constitutes a considerable environmental problem. This article describes biological monitoring employed as part of the basis for assessment of the health risk due to contaminated housing soil. As an example was chosen the environmental contamination with lead and arsenic in Mundelstrup Station Town, where a manure factory previously was situated. This area, which was found to be contaminated to a considerable extend with lead and arsenic, was subdivided for living area in 1921. The present material includes 99 residents from a housing area with 30 family houses with gardens in Mundelstrup. At the commencement of the investigation in 1988/1989, blood lead levels and arsenic levels in the urine were measured and the latter were repeated in 1989/1990. For both adults and children, the blood lead levels were the same as in the reference populations. Children below 12 years had in the average higher arsenic contents in the urine compared with women and men: 16.3 mu/l 8.6 mu/l and 11.5 mu/l, respectively. For both children and adults, the arsenic values were similar to those in a limited Danish reference population. In Ruston, an area in USA heavily polluted with arsenic, contamination of the surface was found to correspond to a factor ten times higher than in Mundelstrup where arsenic is measured at a deeper level. Correspondingly, arsenic values in the urine revealed higher average values in children, 30 micrograms/l for females and 65 micrograms/l for males. The average values for the reference group were found to be 11.3-13.0 micrograms/l.(ABSTRACT TRUNCATED AT 250 WORDS)

High performance liquid chromatography method for rapid and accurate determination of homocysteine in plasma and serum

Determination of homocysteine in plasma or serum for evaluation of cobalamin and folate deficiency is becoming an important diagnostic procedure. Accurate, rapid and low cost methods for measuring homocysteine are therefore required. We have improved an HPLC method and made it suitable for clinical application. The more important changes are the addition of an internal standard, mercaptopropionylglycine, and the use of a plasma/serum based calibration material. The method consists of the following steps: reduction of the sample with tri-n-butylphosphine, precipitation of proteins, derivatisation with ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate, and HPLC separation followed by fluorescence detection. The linearity of the assays is established and the coefficient of variation is 3.0%. Stability studies show that blood samples must be cooled or centrifuged immediately after venipuncture. The method is useful for evaluation of cobalamin or folate deficiency, especially in patients with normal or moderately depressed cobalamin or folate concentrations in blood.

[Neuropsychological sequelae after electric accidents]

No investigations have been found in the literature which document how many individuals develop neuropsychological and neuropsychiatric dysfunctions following electric shock. Three cases are reviewed in this article where patients developed neuropsychological dysfunction after electric accidents. The first case report describes a man who developed an amnestic syndrome followed by personality changes and diffuse anxiety after an electric accident. The two other case reports are comparable to the post-concussional syndrome. The patients had difficulty in concentration, psychosomatic symptoms and anxiety reactions. On the basis of the case reports described here, it is important to emphasize that manifest or discrete neurological, neuropsychological and neuropsychiatric dysfunctions may occur as sequelae of electric shock. It is therefore of significance to submit patients of this type to neurological examination and neuropsychological and personality psychological investigations in order to reveal possible neurological and psychological disturbances.

Influence of a concentrated ethylester compound of n-3 fatty acids on lipids, platelets and coagulation in patients undergoing coronary bypass surgery

Twenty patients accepted for coronary bypass surgery were randomized to receive either a concentrated ethylester compound of n-3 fatty acids, with a daily dose of 3.15 g of eicosapentaenoic acid (EPA) and 1.89 g of docosahexaenoic acid (DHA), or corn oil (controls) in a double blind study, to evaluate the effect on lipids, platelets and coagulation during the pre- and postoperative phase. Only patients with fasting triglyceride (TG) levels greater than or equal to 1.6 mmol/l at recruitment were eligible. The study was continued for 5 to 6 months. Surgery was usually performed at mid-intervention. Blood samples were collected during morning hours in fasting subjects, just prior to intervention, preoperatively and at final postoperative follow-up. Moreover, blood loss was accurately accounted for postoperatively. A threefold increase (p = 0.0001) of EPA was noted at pre- and postoperative follow-up. TG-levels were reduced 20 and 39%, respectively, in patients on n-3 fatty acids, reaching statistical significance at end of intervention (p = 0.034). TG-levels in controls remained largely unchanged. In patients on n-3 fatty acids, there was a statistically significant increase in serum total cholesterol preoperatively, but this change was no longer present at completion of the study. No significant changes were noted in platelet function, as judged by bleeding time, collagen induced platelet aggregation and release of TxB2 during aggregation. Parameters of extrinsic coagulation, including phospholipase C-sensitive factor VII (PLC-VII) and extrinsic pathway inhibitor (EPI), also remained essentially unchanged in both groups of patients. However, fibrinogen was significantly reduced in controls (p less than 0.05) at end of intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharyngeal carriage of Neisseria meningitidis and Neisseria lactamica in households with infants within areas with high and low incidences of meningococcal disease

In a household survey in the Faroe Islands, an isolated community with hyperendemic occurrence of meningococcal disease due to serogroup B 15, 1604 persons were examined for pharyngeal carriage of Neisseria meningitidis and N. lactamica. Two areas were chosen having experienced high (HIA), and two having experienced low incidences (LIA) of disease. Living in HIA compared with LIA was associated with higher risk of N. meningitidis B 15 carriage and lower risk of N. lactamica carriage, with odds ratios of 2.7 (95% confidence interval (CI) 1.4-5.1, P = 0.003) and 0.41 (95% CI 0.31-0.53, P less than 0.0001), respectively. In HIA the risk of N. meningitidis carriage was much lower in non-carriers than carriers of N. lactamica, with an odds ratio of 0.19 (95% CI 0.08-0.47, P = 0.0003); in LIA this association (odds ratio 0.51, P = 0.05) was much weaker. Children 0-14 years had substantially higher risk of being carriers of N. meningitidis group B 15 if the mothers were so, with an odds ratio of 11 (95% CI 4-29, P less than 0.0001).

[Social and health inequality in an area of community housing in Odense]

This investigation is a cross-sectional investigation based on the registers available which describe the conditions of health in children born in 1978 and resident in 1987 in two different social districts, one of which was socially, stressed while the other was slightly less stressed. The vaccination coverage was found to be lower in the socially stressed district and lower among immigrant children. More unvaccinated children were observed among children of mothers who received public assistance and of single parents. Hospital admissions on account of diagnoses due to infection were thrice as frequent from the socially stressed district. As regards height, weight and psychomotor status, no differences were observed between the districts. The investigation indicates that social inequalities cause health inequalities and that, in particular, there appears to be a need for health-promoting efforts where the socially stressed environments are concerned e.g. immigrant families.

[Are health and disease equally distributed among children?]

Living conditions for children and young people are of great interest. In previous investigations, differences in sickness among social groups have been found. WHO plans to reduce differences in health conditions among groups within the countries by at least 25%. In this article, attention is drawn to inequalities in health among children in Denmark. Parameters such as the risk of stillbirth, congenital malformations and death during the first year of life do not differ between social groups. Where the less harsh data are concerned, inequalities still exist between social groups, also among Danish children. In relation to the goals set by WHO, it is important to be aware that the existing ways of measurement may not be sufficient.

NMDA receptor antagonists suppress behaviors but not norepinephrine turnover or locus coeruleus unit activity induced by opiate withdrawal

Pretreatment with the non-competitive NMDA (N-methyl-D-aspartate) antagonist MK801 (0.5, 1.0 mg/kg, s.c.) suppressed the behavioral signs of withdrawal in morphine-dependent rats. However, the same doses of MK801 that suppressed morphine withdrawal also simultaneously produced phencyclidine (PCP)-like behaviors. Pretreatment with the competitive NMDA antagonist LY274614 (25, 50, 100 mg/kg i.p.) also suppressed the behavioral signs of withdrawal in morphine-dependent rats but did not produce PCP-like behavioral effects. Single unit recordings were made from noradrenergic neurons in the locus coeruleus (LC) and, at doses that suppressed morphine withdrawal behaviors, neither MK801 nor LY274614 blocked the withdrawal-induced activation of LC neurons. Biochemical analysis indicated that, at the same behaviorally relevant doses, neither MK801 nor LY274614 blocked the withdrawal-induced increase in norepinephrine turnover in the hippocampus, cerebral cortex, or hypothalamus. These results indicate that NMDA antagonists attenuate the behavioral signs of morphine withdrawal without blocking the withdrawal-induced increase in norepinephrine turnover or the withdrawal-induced increase in LC unit activity. In addition, non-competitive NMDA antagonists, like MK801, may not be useful to alleviate opiate withdrawal symptoms in man because of their PCP-like side effects. However, competitive NMDA antagonists, like LY274614, could be of great benefit for alleviating opiate withdrawal symptoms in man.

[Simultaneous measurement of end-diastolic pressure in the left ventricle and transmitral flow before and after nitroglycerin in patients with angina pectoris]

In angina pectoris, left ventricular diastolic function evaluated by end-diastolic pressure (LVEDP) on catheterization and transmitral flow (TMF) on Doppler echocardiography is abnormal. As a parameter describing TMF, the ratio between peak flow velocities of the two filling phases in diastole (PE/PA) can be used. We examined 22 patients with angina pectoris and measured LVEDP and PE/PA simultaneously and found positive correlation (r = 0.60). Nitroglycerin (0.8 mg sublingually) reduced LVEDP and PE/PA significantly, and correlation between reductions was positive (r = 0.52). None of the correlation analyses permitted LVEDP to be calculated from PE/PA, but Doppler echocardiography and TMF will probably be used increasingly in evaluation of ischemic heart disease with medical intervention.

Application of fluorescence in situ hybridization techniques in clinical genetics: use of two alphoid repeat probes detecting the centromeres of chromosomes 13 and 21 or chromosomes 14 and 22, respectively

Two cloned DNA fragments, one derived from an alpha satellite subfamily common to chromosomes 13 and 21, and the other derived from a similar subfamily common to chromosomes 14 and 22, have been used as biotinylated probes in in situ hybridization studies. Under high stringency conditions, chromosome specific centromeric labelling can be obtained. The applications of this technique in clinical situations are illustrated on metaphases from a fetus with trisomy 21, a fetus with trisomy 13, and a child with clinical features of cat-eye syndrome.

[Health surveillance of workers exposed to lead in the County of Arhus]

The lead directive issued by the Danish Ministry of Labour in 1985 is the first Danish work environment directive in which the expression "health surveillance" is employed. By this is understood a systemic programme of surveillance for control of the conditions of health of the workers. This article presents the results of the first 16 months of the continuous surveillance programme initiated by the Labours Inspectorate in the County of Arhus. The material comprizes 118 factories with 572 workers who were exposed to lead and a total of 730 blood lead and 78 lead dust measurements. The most exposed branches were metal foundries, repairs to motor coolers, plastic foundries, trade with products and, to a certain extent, car painting. During the initial phase of the surveillance programme, blood lead levels resulted in health examination of eight workers. In one of these, chronic dementia was found, probably caused by a combination of exposure to organic solvents and lead for many years. In another worker, a manifest acute lead poisoning was diagnosed. The literature about the toxicity of lead provides increasing documentation of effects on health even in such a low dosage-range as the current Danish exposure level i.e. corresponding the blood lead values 10-50 micrograms/100 ml. It is concluded that the lead directive has been suitable constructed when prophylaxis in the work environment employing health supervision is concerned. Similar programmes could be considered for occupational exposure to mercury, cadmium and cobolt.