Specific fibrinogen quantitation by electroimmunodiffusion in agarose gel containing heparin.

In the determination of plasma fibrinogen by electroimmunodiffusion, commercial sodium heparin, previously included in the agarose gel, by interacting with fibrinogen molecules, enhances their anodic mobility more strongly than after carbamylation with potassium cyanate. The proposed method provides an increase in sensitivity and specificity which practically eliminates the influence of fibrinogen degradation products.

Evaluation of an ELISA kit for epidemiological detection of antibodies to Plasmodium falciparum sporozoites in human sera and bloodspot eluates.

Antibodies to Plasmodium falciparum sporozoites represent a serological transmission indicator, which can be applied in epidemiological studies to estimate the intensity of malaria transmission. An ELISA method has been developed as an industrial kit to detect these antibodies, using a chemically synthesized (NANP)40 peptide as antigen. The results obtained with this kit are compared in the present paper with those obtained by an ELISA test already applied in epidemiological studies. In testing sera from individuals living in endemic areas, a high diagnostic concordance (92.1%) was obtained between the two assays. The absorbances of these sera correlated well, as shown by a correlation coefficient r = 0.877. Sera from individuals never exposed to malaria gave very low absorbances with the kit. This minimum non-specific binding increases the probability of comparable results in different studies. When the two ELISAs were evaluated for analytical sensitivity and precision, similar satisfactory results were achieved. The test can be performed not only with sera but also with eluates from filterpaper bloodspots. Modifications of the kit to reduce its cost and suggestions regarding distribution and funding are also proposed.

[Persistence of circulation of Corynebacterium diphtheriae non-toxigenic strains and low prevalence of carriers in a sample of children vaccinated against diphtheria]. / Persistente circolazione di ceppi non tossigeni di Corynebacterium diphtheriae e bassa prevalenza di portatori in un campione di bambini vaccinati contro la difterite.

This study was carried out with the aim to investigate the presence of carriers of diphtheria bacillus in a sample of 1970 healthy children, 6-14 years aged, residing in eight Italian towns. Three non-toxigenic strains of Corynebacterium diphtheriae biotype mitis were isolated from as many healthy children. Molecular characterization by ribotyping showed close genetic relation of two of the wild strains with the C7(b) reference strain whereas one of the wild strains showed close genetic relation with two collection strains isolated in the same geographic area (Emilia-Romagna) from diphtheria patients in the seventy years. This supports the hypothesis of the persistence of some non toxigenic C. diphtheriae strains derived from ancient endemic strains under the selective pressure of mass immunization against diphtheria. The persistence of carriers of diphtheria bacilli, although non toxigenic, suggests that high levels of immunity must be maintained, not only in children, but also in adults by booster vaccination.

Radio-ligand-receptor assay for human chorionic somatomammotropin (hCS), ovine prolactin (oPRL) and human growth hormone (hGH) using rat ventral prostate particles.

A radio-ligand-receptor assay with a sensitivity of 6.5 x 10(-3) mIU of ovine prolactin per tube has been developed for human chorionic somatomammotropin (hCS) and other lactogenic hormones, using as specific ligand the microsomal pellet of rat ventral prostate. This particulate fraction has proved more suitable than the same fraction obtained from rabbit mammary gland in the evaluation of the prolactin-like activity of purified preparations of hCS.

Evidence of increased carriage of Corynebacterium spp. in healthy individuals with low antibody titres against diphtheria toxoid.

This study evaluated whether a correlation exists between carriage of corynebacteria and the lack of immunity to diphtheria toxoid. Samples of both nasal and pharyngeal secretions were taken from 500 apparently healthy subjects of both sexes and of all ages and inoculated onto Tinsdale's medium. A serum sample was also taken for ELISA test to determine the titre of diphtheria toxin antibodies. None of the subjects carried Corynebacterium diphtheriae. Ninety-three strains of Corynebacterium spp. were isolated from 93 subjects and 86 of these were classified to species or group level by biochemical tests. C. xerosis was the most common (25.8%) followed by C. pseudodiphthericum (16.1%), C. jeikeium and C. striatum (both 10.8%), and C. urealyticum (9.7%). Three other species accounted for approximately 20% of strains and seven were unclassified as biochemically atypical corynebacteria. Non-protective antibodies to diphtheria toxin were found in 80 of the 93 subjects and a strong statistical association was demonstrated between carriage of corynebacteria and non-protective levels of anti-toxin antibodies. The remaining 13 subjects had protective levels of antitoxin antibodies. In contrast, only 45 of the 407 non-colonized subjects had non-protective antitoxin titres. The prevalence of carriage increased with age among males as did the percentage of non-protected subjects. The prevalence of female carriers of corynebacteria was significantly lower. Serum samples from 12 subjects with different antibody titres to diphtheria toxoid reacted to varying degrees with whole-cell lysates of a number of species of corynebacteria. The results suggest that a causal relationship may exist between nasopharyngeal carriage of corynebacteria and a low anti-diphtheria toxin immune response.

Prevalence of sleep disorders in childhood and adolescence with headache: a case-control study.

Although a relationship between headache and sleep disturbances has been reported in adults, only few data have been available in children. Accordingly, we performed a survey to determine the prevalence of sleep disturbances in children with migraine and tension-type headache. A questionnaire of history and clinical data and of sleep disturbances was given to parents of 283 headache subjects (164 with migraine and 119 with tension-type headache). Results were compared to a normative group comparable for age and sex of 893 normal healthy subjects. Migraine subjects showed a higher prevalence of sleep disturbances during infancy as well as 3-month colic. In both headache groups, more parents had sleep disturbances and there was a higher occurrence of co-sleeping and napping. A high frequency of sleep disturbances involving sleep quality, night awakenings, nocturnal symptoms and daytime sleepiness was reported in headache children. No statistical differences were found in the prevalence of sleep disturbances between migraine and tension-type headache. However, the migraine group tended to have "disturbed sleep" more often with increased prevalence of nocturnal symptoms such as sleep breathing disorders and parasomnias. Our results give further support to an association between sleep and migraine that may have a common intrinsic origin.

Studies on the stability of rat testis membrane receptors for hLH, hCG and hFSH.

Receptor preparations from rat testes were stored at 4 C with various protease inhibitors and chemicals, at -20 C and -80 C, in freeze-dried form as well as at 4 C and 37 C after reconstitution in various media. Each preparation was tested for stability in terms of binding capacity of human luteinizing hormone (hLH), human chorionic gonadotropin (hCG) and human follicle-stimulating hormone (hFSH). The freeze-dried samples were stable for at least six months, although once reconstituted and stored at 4 C, they were less stable than fresh ones. Furthermore, Na azide and Na azide with diisopropylfluoro-phosphate (DIFP) prolonged the stability of the fresh samples. The samples stored at -20 C or -80 C were stable for at least 90 days and repeated freezing and thawing (15 times) did not change the binding capacity of either the hCG/hLH or hFSH receptors.

Chemical, biological and immunological characterization of separated electrophoretic components of human chorionic somatomammotropin (HCS).

Purified HCS preparations ofter show heterogeneity when assayed by electrophoresis, although they may be considered homogeneous according to other criteria (N-terminal amino acid analysis, gel filtration and ultracentrifugation patterns, etc.). Using DEAE-cellulose chromatography, the two main components corresponding to various degrees of hormone amidation were separated. The deamidation kinetic of the electrophoretically slower migrating component was studied and found to be sensitive to temperature and, to a lesser extent, to pH. Denaturing agents strongly increased the deamidation rate, while no effect was found by raising the ionic strength. No difference was evident between the two components and the parent hormone when compared (on a weight basis) in a specific HCS radioimmunoassay system. Even the precipitin reaction in agar gel with an anti-human growth hormone (HGH) serum did not show variations in cross-reactivity versus HGH. Moreover, groups of guinea pigs immunized with the single HCS components, gave antibodies reacting identically with the components and the parent HCS. The prolactin-like activity of the two components differed when determined by the pigeon crop-sac asay: the slower migrating component proved to be less active than the more deamidated one. On the other hand, the activity in two different radioreceptor assays (employing membranes from rabbit mammary gland and rat ventral prostate) was greater for the faster migrating component.

Immunity to diphtheria in Siena.

The aim of this study, carried out in 1993, was to evaluate diphtheria immunity in Siena. Diphtheria antitoxin levels were measured by means of the immunoenzymatic test (ELISA) in serum samples of 602 apparently healthy subjects (239 males and 363 females) of all ages residing in Siena. According to widely used criteria, 6% of the total population were susceptible to diphtheria (antibody levels < 0.01 IU/ml), 71% had basic protection (0.01-0.09 IU/ml) and 23% were fully protected (> or = 0.1 IU/ml). The results suggested that a high proportion of young population had a protective level of immunity against diphtheria, that susceptibility increased with age and a smaller proportion of males (2.9%) than females (8.3%) were unprotected; this difference was statistically significant. Our results suggest that it may be useful to revaccinate adults with low levels of diphtheria toxoid so that the percentage that remains unprotected does not put the community at risk of an outbreak of diphtheria.

Headache and psychiatric comorbidity: clinical aspects and outcome in an 8-year follow-up study.

UNLABELLED: Migraine with juvenile onset changes over time. The existence of prognostic factors is a point of focus. A strict relationship between migraine or tension-type headache (TTH) and psychiatric factors has been suggested, but the exact role and the influence on evolution of headache is unknown. OBJECTIVE: To analyze the evolution of migraine and TTH and psychiatric comorbidity (P-Co) from 1988 to 1996. MATERIAL AND METHOD: 100 subjects (40M, 60F; mean age 17.9 years; SD 2.7 years; range 12-26 years) were examined at our Center. The International Headache Society (IHS) criteria were employed. Psychometric tests and clinical interviews aided psychiatric diagnosis (DSM-III-R). SCID (Structured Clinical Interview for DSM-III-R) was employed in 1996. Chi square and logistic regression are used for statistical analysis. FINDINGS: Migraine and TTH change their clinical characteristics, with a high tendency to remission (mostly in males). The presence of P-Co in 1988 is related to a worsening or unchanging situation in 1996. Headache-free subjects did not present any psychiatric disorders in 1996. Anxiety disorders in 1988 are related to enduring of headache. Migraine shows comorbidity with anxiety disorders and depression. CONCLUSION: P-Co is a notable problem in clinical practice. Diagnostic, prognostic, and treatment implications require a systematic assessment of P-Co.

Prevalence of diphtheria toxin antibodies in human sera from a cross-section of the Italian population.

A polycentric study was carried out between 1993 and 1995 in order to evaluate diphtheria immunity on a representative sample of population from different areas of Italy. To determine diphtheria antitoxin, sera from 5187 apparently healthy subjects, divided according to sex and age groups, were titrated using an ELISA indirect method. A basic protective titre of diphtheria antitoxin (> 0.01 IU ml-1) was found in 4080 (78.6%) subjects. No statistically significant differences between males and females were observed. Our findings show that the proportion of susceptibles increases with age and a high proportion of adults no longer has diphtheria antitoxin at protective levels since toxigenic C. diphtheriae circulation is presently lacking in Italy.