Detection of an anatoxin-a(s)-like anticholinesterase in natural blooms and cultures of cyanobacteria/blue-green algae from Danish lakes and in the stomach contents of poisoned birds

Ten natural bloom samples of cyanobacteria from the Danish lakes Knud s? (5), Ravn s? (4), and Salten Langs? (1) collected during 1993-1995 were assayed for toxicity by mouse bioassay, for acetylcholinesterase inhibiting activity by a colorimetric method, and for microcystins by enzyme-linked immunosorbent assay. In the mouse bioassay, seven samples were neurotoxic, two were non-toxic and one gave a protracted toxic response. One of the non-toxic and the single protracted toxic sample both contained anticholinesterase activity equivalent to 4 micrograms anatoxin-a(s) g-1. The neurotoxic samples contained equivalents to 20-3300 micrograms anatoxin-a(s) g-1. The highest anticholinesterase activities (equivalent to 2300 and 3300 micrograms anatoxin-a(s) g-1, respectively) were found in samples collected from Lake Knud s? in connection with bird-kills in 1993 and 1994. Small amounts of microcystins (0.1-0.9 microgram g-1) were detected in all samples but one. All Lake Knud s? and Lake Ravn s? samples were dominated by Anabaena lemmermannii, and the Lake Salten Langs? sample by several species of Anabaena. Gel filtration profiles indicated similarity between the toxic component from the Lake Knud s? 1994 bloom with registered bird-kills and anatoxin-a(s) isolated from Anabaena flos-aquae NRC-525-17. Anticholinesterase-producing cultures of A. lemmermannii were isolated from the Lake Knud s? 1993 bloom. These laboratory cultures produced anatoxin-a(s) equivalents of 29-743 micrograms g-1. Other cultures of A. lemmermannii isolated from Lake Knud s? and Lake Ravn s? were hepatotoxic or non-toxic. Dead birds collected from Lake Knud s? during the neurotoxic 1993 Anabaena bloom possibly died from cyanobacterial toxicosis. The stomach contents contained colonies and single trichomes of Anabaena, and anticholinesterase activities equivalent to 2.1-89.7 micrograms anatoxin-a(s) kg-1 body weight and microcystins (53-95 ng kg-1) were also detected.     

IL-4- and IL-5-secreting lymphocyte populations are preferentially stimulated by parasite-derived antigens in human tissue invasive nematode infections

Helminth infections in humans and animals are associated with strong T helper 2 (Th2) responses. To determine whether parasite-derived Ag preferentially expand a Th2-like cell population, a filter immunoplaque assay was used to enumerate the frequencies (F0) of PBMC and CD4(+)-enriched PBMC from individuals with helminth infections secreting selected cytokines in response to parasite-derived (PAg) and nonparasite antigens (NPAg). In 20 individuals with lymphatic filariasis, frequency analysis of PBMC secreting IL-4 and IFN-gamma indicated that the F0 of PAg-specific IL-4-secreting cells (geometric mean F0 (GM): 1/12,100) was 57-fold higher than the corresponding F0 of NPAg-reactive cells (GM: 1/692,000; p < 0.02). In marked contrast, the F0 of IFN-gamma-secreting cells responding to PAg (GM: 1/2,700) did not differ from those of cells specific for NAPg (GM: 1/3,400; p = 0.83). In another group of helminth-infected individuals, the F0 of highly enriched CD4+ cells secreting IL-4 and IL-5 in response to PAg (GMs: 1/2,600 and 1/5,600 CD4+ cells, respectively) were also found to be significantly higher than those specific for NPAg (GMs: 1/291,000 and 1/303,000 CD4+; p < 0.05 and p < 0.01, respectively), whereas the corresponding F0 of IFN-gamma- and granulocyte-macrophage-CSF-secreting cells were equivalent for PAg and NPag. Furthermore, the proportion of PAg-specific IL-4- and IL-5-secreting CD4+ cells relative to all cells secreting the given cytokine were approximately 29-fold higher than the proportion of NPAg-specific cells secreting these cytokines. Again, the corresponding proportions of Ag-specific IFN-gamma-and GM-CSF-secreting CD4+ cells were equivalent for PAg and NPAg. Thus, in this ex vivo system, a circulating population of IL-4- and IL-5-secreting (Th2-like) cells has been shown to exist in humans; PAg appears to expand these cells preferentially.     

Altered basal and insulin-stimulated phosphotyrosine phosphatase (PTPase) activity in skeletal muscle from NIDDM patients compared with control subjects

To measure possible changes in basal and insulin-stimulated phosphotyrosine phosphatase (PTPase) activity in skeletal muscle from insulin-resistant individuals, soluble and particulate muscle fractions were prepared from biopsies taken before and after a 3-h hyperinsulinaemic euglycaemic clamp in eight non-insulin-dependent diabetic (NIDDM) patients and nine control subjects. We used a sensitive sandwich-immunofluorescence assay and the human insulin receptor as the substrate. PTPase activity was expressed as percentage of dephosphorylation of phosphotyrosyl-residues in immobilized insulin receptors per 2 h incubation time per 83 micrograms and 19 micrograms muscle fraction protein (soluble and particulate fraction, respectively). In the diabetic soluble muscle fractions, the basal PTPase activity was decreased compared with that of control subjects (11.5 +/- 5.5 vs 27.5 +/- 3.3, p < 0.04, mean +/- SEM). In the particulate muscle fractions from the control subjects, PTPase activity was increased after 3 h hyperinsulinaemia (20.0 +/- 3.2 vs 30.2 +/- 3.6, p < 0.03) and in the corresponding soluble fractions PTPase activity seemed decreased (27.5 +/- 3.3 vs 19.9 +/- 5.9, NS). No effect of insulin on PTPase activity was found in NIDDM patients (25.1 +/- 4.1 vs 27.2 +/- 5.2, 11.5 +/- 5.5 vs 15.1 +/- 4.5 [particulate and soluble fractions], NS). In conclusion, we found that the basal PTPase activity in soluble muscle fractions was decreased in NIDDM patients; furthermore, insulin stimulation was unable to increase PTPase activities in the particulate fractions, as opposed to the effect of insulin in control subjects.     

Abnormal behavioral responses to fenfluramine in patients with affective and personality disorders. Correlation with increased serotonergic responsivity

Serotonergic responsivity was assessed in 20 psychiatric patients by the prolactin response to a fenfluramine challenge test. During the fenfluramine challenge 6 of 20 patients (30%) spontaneously reported psychopathologic reactions that included: increased anxiety/agitation, psychotic symptoms, illusions, mood elevation, and anergia. The time of peak behavioral symptoms (2.5 +/- 0.8 hrs) corresponded closely to the time of peak increase in prolactin levels (3.0 +/- 1.1 hr). Abnormal behavioral responders had statistically significant greater increases in prolactin 1 to 4 hr after fenfluramine when compared to normal responders. Patients who developed an abnormal psychopathologic response to fenfluramine were characterized by higher levels of anxiety and agitation at the time of admission to the hospital but otherwise were not distinguishable on the basis of severity of other psychiatric symptoms. This study suggests that increased serotonergic transmission may trigger anxiety, psychosis, and mood elevation in specific vulnerable individuals, whereas other patients with similar psychiatric illnesses are not affected.     

Selective activation by bryostatin-1 demonstrates unique roles for PKC epsilon in neurite extension and tau phosphorylation

The purpose of this study was to contrast the discharge patterns of the same motor units during movements and during isometric contractions that were produced with comparable torque-time characteristics. Subjects performed elbow flexion and extension movements with predetermined acceleration characteristics. The average acceleration and deceleration profiles for the movements were reproduced in the isometric setting by presenting the kinematic profiles as templates for torque production. Trained subjects were able to match the first agonist (AG1) and antagonist (ANT) electromyographic (EMG) bursts, but tended to produce a smaller second agonist burst (AG2) in the isometric contraction. Twenty-five motor units from triceps brachii were studied. The same motor units (with one exception) were recruited and subsequently discharged in a similar fashion in both the isometric and movement tasks in the AG1 and ANT EMG bursts, with fewer motor unit discharges in the AG2 burst in the isometric contraction. The central control mechanisms appear to be the same for the acceleration phase of movement and isometric contraction, but differ during the deceleration phase.     

Exclusion of BMP6 as a candidate gene for cleidocranial dysplasia

Cleidocranial dysplasia (CCD) is an autosomal dominant, generalized skeletal dysplasia in humans that has been mapped to the short arm of chromosome 6. We report linkage of a CCD mutation to 6p21 in a large family and exclude the bone morphogenetic protein 6 gene (BMP6) as a candidate for the disease by cytogenetic localization and genetic recombination. CCD was linked with a maximal two-point LOD score of 7.22 with marker D6S452 at theta = 0. One relative with a recombination between D6S451 and D6S459 and another individual with a recombination between D6S465 and CCD places the mutation within a 7 cM region between D6S451 and D6S465 at 6p21. A phage P1 genomic clone spanning most of the BMP6 gene hybridized to chromosome 6 in band region p23-p24 using FISH analysis, placing this gene cytogenetically more distal than the region of linkage for CCD. We derived a new polymorphic marker from this same P1 clone and found recombinations between the marker and CCD in this family. The results confirm the map position of CCD on 6p21, further refine the CCD genetic interval by identifying a recombination between D6S451 and D6S459, and exclude BMP6 as a candidate gene.     

Confirmation of anatoxin-a(s), in the cyanobacterium Anabaena lemmermannii, as the cause of bird kills in Danish lakes

Cyanobacterial blooms were implicated in bird kills at lakes in Denmark in July 1993 and June-July 1994. These blooms were dominated by Anabaena lemmermannii and were shown to contain a neurotoxin with anticholinesterase activity. In this study, the toxin was isolated by mouse lethality guided column chromatographies from the field sample collected at Lake Knud s? in 1993. Various spectroscopic data indicated that the toxin was anatoxin-a(s), an irreversible anticholinesterase, first reported in Anabaena flos-aquae. Chemical detection of the same toxin in cultured A. lemmermannii also confirmed this species as the cause of the deaths of the wild birds.     

The posterior operative approach for cervical radiculopathy

Cervical disc disease includes acute herniation and chronic disc degeneration with secondary changes in the associated bone. The latter may lead to the spectrum of cervical spondylitic stenosis, which is considered to be multilevel and may be more of a bony disease. Clinically, cervical disc disorders can be divided into several disorders. The disorder of true cervical radiculopathy is associated with lateral compression of the nerve root. When this condition is due to a lateral soft disc herniation or lateral bony stenosis, the posterior cervical laminoforaminotomy is commonly used. It is a procedure that works extremely well in the vast majority of patients and there is no risk of spinal instability; therefore, no fusion is required. The details of operative care have been described. In patients who have persistent radicular problems after a failed anterior cervical interspace procedure, the posterior cervical laminoforaminotomy with posterior wiring and fusion is a simple and effective operative option.     

Expert statement and assessment of medical impairment in work-related pulmonary disease

The Norwegian Societies of Thoracic Medicine and Occupational Medicine established a working group to standardise diagnostic procedures and evaluation of work-related respiratory disorders. In cases of suspected work-related diseases the physician may be asked by the National Insurance Administration or an insurance company to make a statement which will be one of the documents used to decide the patient's right to compensation benefit. We discuss the role of the physician as an independent expert. This is different from his role as clinician. The statement should include a balanced presentation of information from different sources, including health and occupational history, and the employer's information about the work environment (quantitative and qualitative exposure data). The statement must also include the results of a clinical examination and an assessment of functional status based on objective tests. The paper contains recommendations for evaluation of permanent impairment in light of the present Norwegian laws and regulations.     

Magnetic resonance imaging of disseminated sclerosis

Multiple sclerosis is a chronic demyelinating disease. Paraclinical examinations may contribute to the diagnosis of multiple sclerosis. Magnetic resonance imaging (MRI) has a very high sensitivity concerning multiple sclerosis, and has made it possible to visualize multiple sclerosis plaques in vivo, to follow each plaque over the course of time and in this way to obtain information about the pathogenesis. MRI has shown that the size of plaques may vary considerably, and that plaques are dynamic structures with the ability to change in size over few weeks. By using MRI and the contrast agent Gadolinium-DTPA, it is possible to distinguish a newly developed plaque from an older one. Therefore, MRI has become an important examination in therapeutic trials. Just now, MRI with Gadolinium-DTPA is being used to evaluate the efficacy of plasmapheresis and immunoglobulin treatment in a joint study between Rigshospitalet and Hvidovre Hospital.