123I-amphetamine-SPECT in classical migraine and migraine accompagnée

Migraine is considered to be a functional neurological disorder. In classical migraine (headache associated with prodromal visual field disturbances) and migraine accompagnée (headache associated with transient neurological symptoms), disturbances of cerebral blood flow and amine metabolism are thought to be pathogenetic factors. However, conventional methods of neuroimaging (CAT, NMR) usually do not yield any pathological findings in patients. Since 123I-iodoamphetamine (123I-IMP) crosses the intact blood brain barrier, 123I-IMP-SPECT is used for the assessment of cerebral perfusion in various neurological diseases, including functional disorders. 123I-IMP-SPECT was performed on 5 patients with classical migraine and 18 patients with migraine accompagnée. At the time of investigation, all patients were symptom-free. Cerebral blood flow was decreased in all patients with migraine accompagnée, and often corresponded to the site of headache as well as to the topography of transient neurological symptoms. This reduction was most obvious in a patient with persisting neurological symptoms. Most patients with classical migraine, however, did not show any alteration of cerebral perfusion. It appears that migraine--and in particular migraine accompagnée--is characterized by a permanent alteration not only of cerebral blood flow but also of neuronal activity. Migraine attacks may occur in connection with exacerbations of preexisting metabolic alterations.     

Protection from Shigella sonnei infection by immunisation of rabbits with Plesiomonas shigelloides (SVC 01).

Plesiomonas shigelloides, an organism commonly found in water, is only rarely associated with diarrhoea in man. P. shigelloides serotype O:17 (SVC O1), which is antigenically similar to Shigella sonnei, was found to be neither virulent nor toxic for rabbits. Rabbits immunised by feeding with P. shigelloides (SVC O1) were completely protected against an oral challenge with 10(10) cells of S. sonnei but non-immunised rabbits were not. P. shigelloides (SVC O1) may be a useful vaccine strain for shigellosis.     

Radioresponsiveness, sublethal damage repair and stem cell rate in spheroids from three human tumor lines: comparison with xenograft data.

Dose-control curves after fractionated irradiation were generated for small oxic spheroids from the two human glioma cell lines, U87 and A7, as well as the squamous cell carcinoma line FaDu. These data were fitted by the linear quadratic model assuming Poisson statistics. The alpha/beta values of A7, U87, and FaDu spheroids, respectively were 10.3 (8.1-12.9) Gy, 17.8 (15.1-21.1) Gy, and 37.9 (29.1-51.5) Gy. These data were compared with those previously published by Suit et al. (31) and Zietman et al. (40) for 6 mm xenografts of U87 and FaDu after fractionated irradiation and for A7 after single dose irradiation under clamped conditions. A good agreement in the alpha/beta values was observed for U87 and Fadu xenografts and spheroids assuming an oxygen enhancement ratio (OER) of 2.7. In addition, the ranking according to the single doses needed to control 50% of the tumors agreed for xenografts and spheroids from the three cell lines. U87 was the most resistant line in both model systems, followed by A7 and FaDu. However, the absolute values of alpha and beta, obtained from the direct fit to the dose-control data were only about half as high for U87 and FaDu xenografts than for the spheroids. Monte Carlo simulations showed that this discrepancy can be explained by a greater tumor heterogeneity of the xenografts. While the number of critical stem cells or spheroid rescuing units equaled the number of cells per spheroid for the three cell lines, the percentage of tumor rescuing units for Fadu and U87 xenografts was estimated to be below 1%. In a next step, survival curves were generated for exponentially growing cells of the three lines. A7 cells were significantly more radioresistant when plated on tissue plastic than in soft agar. Using the most resistance-promoting colony assay conditions for each cell line, a good agreement was observed for the alpha and SF2Gy values calculated from the colony and spheroid control data. This study shows that the spheroid model can quantitatively predict the repair capacity of sublethal damage as well as the rank order of radiation sensitivity of in vivo tumors.     

Neuroendocrine response to 5-hydroxytryptophan in seasonal affective disorder

A double-blind random-ordered comparison of the effects of placebo and 5-hydroxytryptophan (200 mg, orally) in ten depressed patients with seasonal affective disorder (SAD) and ten controls disclosed slightly but significantly higher basal levels of serum prolactin and a trend toward higher basal levels of serum cortisol in the patients with SAD compared with controls. After administration of 5-HTP, the cortisol level significantly increased and the prolactin level significantly decreased in both patients and controls. No differences in the melatonin level, growth hormone level, blood pressure, or pulse rate and no side effects were noted between patients and controls in the two study conditions; the timing of basal and 5-hydroxytryptophan-stimulated hormonal secretions was similar for both groups. These results are discussed with reference to current hypotheses of the cause of SAD.     

Serotypes of Streptococcus pneumoniae causing invasive childhood infections in Bangladesh, 1992 to 1995.

One hundred sixty-five invasive Streptococcus pneumoniae strains were isolated from children under five at Dhaka Shishu (Children's) Hospital during the period 1992 to 1995. Ninety-four strains were from cerebrospinal fluid, and 71 were from blood. More than 91% of the strains were isolated from patients aged 24 months or less. Predominant serotypes were, in descending order 7F, 12F, 14, 15B, 18, 5, and 22A. These comprised 70% of all isolates. The marked differences in serotype distribution in different countries indicate the need for a sentinel surveillance study for the countries of South Asia, particularly Bangladesh, China, India, and Pakistan.     

Enterotoxigenic Escherichia coli in developing countries: epidemiology, microbiology, clinical features, treatment, and prevention

ETEC is an underrecognized but extremely important cause of diarrhea in the developing world where there is inadequate clean water and poor sanitation. It is the most frequent bacterial cause of diarrhea in children and adults living in these areas and also the most common cause of traveler's diarrhea. ETEC diarrhea is most frequently seen in children, suggesting that a protective immune response occurs with age. The pathogenesis of ETEC-induced diarrhea is similar to that of cholera and includes the production of enterotoxins and colonization factors. The clinical symptoms of ETEC infection can range from mild diarrhea to a severe cholera-like syndrome. The effective treatment of ETEC diarrhea by rehydration is similar to treatment for cholera, but antibiotics are not used routinely for treatment except in traveler's diarrhea. The frequency and characterization of ETEC on a worldwide scale are inadequate because of the difficulty in recognizing the organisms; no simple diagnostic tests are presently available. Protection strategies, as for other enteric infections, include improvements in hygiene and development of effective vaccines. Increases in antimicrobial resistance will dictate the drugs used for the treatment of traveler's diarrhea. Efforts need to be made to improve our understanding of the worldwide importance of ETEC.     

Seroepidemiology of rotavirus infection in rural Bangladesh.

A prospective seroepidemiological study of rotavirus infection was performed in children in a village in rural Bangladesh. Ninety-three percent of the children had detectable antibodies during the study, and there were 66 significant rises in titer occurring in 57 of the 85 children. Antibody titer rises occurred in older children and younger children with equal frequency. Nine children (11%) had evidence of multiple infections during the 16-month period. Winter infections were most frequent, although one summer (monsoon) season was also associated with a large cluster. Subjects with high titers (greater than 1:8) of antibody less frequently developed a titer rise than did subjects with lower titers.     

Microtiter solid-phase radioimmunoassay for detection of Escherichia coli heat-labile enterotoxin.

The development of a microtiter solid-phase radioimmunoassay for the detection of Vibrio cholerae enterotoxin and heat-labile Escherichia coli enterotoxin is described. The test is based on the immunological similarity between V. cholerae toxin and E. coli heat-labile toxin. The assay is easy to perform, quantitative, and at least as sensitive and specific as the Y-1 adrenal cell system.