Investigating dynamic pain sensitivity in the context of the fear-avoidance model.

BACKGROUND: Although nearly everyone at some point in their lives experiences back pain; the amount of interference with routine activity varies significantly. The fear-avoidance (FA) model of chronic pain explains how psychological variables, such as fear, act as mediating factors influencing the relationship between clinical pain intensity and the amount of interference with daily activities. What remains less clear is how other mediating factors fit within this model. The primary objective of this report was to examine the extent to which a dynamic measure of pain sensitivity provides additional information within the context of the FA model. METHOD: To address our primary objective, classic mediation and moderated mediation analyses were conducted on baseline clinical, psychological and quantitative sensory measures obtained on 67 subjects with back pain (mean age, 31.4 ± 12.1 years; 70% female). RESULTS: There was a moderately strong relationship (r = 0.52; p < 0.01) between clinical pain intensity and interference, explaining about 27% of the variance in the outcome. Mediation analyses confirmed fear partially mediated the total effect of clinical pain intensity on interference (Δß = 0.27; p < 0.01), and accounted for an additional 16% of the variance. In our FA model, pain sensitivity did not demonstrate additional indirect effects; however, it did moderate the strength of indirect effects of fear. CONCLUSION: This preliminary modelling suggests complex interactions exist between pain-related fear and pain sensitivity measures that further explain individual differences in behaviour.

Plant molecular farming: systems and products.

Plant molecular farming is a new and promising industry involving plant biotechnology. In this review, we describe several diverse plant systems that have been developed to produce commercially useful proteins for pharmaceutical and industrial uses. The advantages and disadvantages of each system are discussed. The first plant-derived molecular farming products have reached the marketplace and other products are poised to join them during the next few years. We explain the rationale for using plants as biofactories. We also describe the products currently on the market, and those that appear likely to join them in the near future. Lastly, we discuss the issue of public acceptance of molecular farming products.

Improved recovery of active recombinant laccase from maize seed.

Lignolytic enzymes such as laccase have been difficult to over-express in an active form. This paper describes the expression, characterization, and application of a fungal laccase in maize seed. The transgenic seed contains immobilized and extractable laccase. Fifty ppm dry weight of aqueously extractable laccase was obtained, and the remaining solids contained a significant amount of immobilized laccase that was active. Although a portion of the extractable laccase was produced as inactive apoenzyme, laccase activity was recovered by treatment with copper and chloride. In addition to allowing the apoenzyme to regain activity, treatment with copper also provided a partial purification step by precipitating other endogenous corn proteins while leaving >90% of the laccase in solution. The data also demonstrate the application of maize-produced laccase as a polymerization agent. The apparent concentration of laccase in ground, defatted corn germ is approximately 0.20% of dry weight.

Plant-based vaccines: unique advantages.

Numerous studies have shown that viral epitopes and subunits of bacterial toxins can be expressed and correctly processed in transgenic plants. The recombinant proteins induce immune responses and have several benefits over current vaccine technologies, including increased safety, economy, stability, versatility and efficacy. Antigens expressed in corn are particularly advantageous since the seed can be produced in vast quantities and shipped over long distances at ambient temperature, potentially allowing global vaccination. We have expressed the B-subunit of Escherichia coli heat-labile enterotoxin and the spike protein of swine transmissible gastroenteritis virus at high levels in corn, and demonstrate that these antigens delivered in the seed elicit protective immune responses.

Neonatal screening for haemoglobin variants using filter paper-dried blood specimens.

Neonatal screening for haemoglobinopathies utilizing cord blood samples is well established, although it has a high miss rate and has the inherent problem of possible misdiagnosis from maternal contamination of the sample. The use of dried Guthrie card samples which are taken at six days of age avoids these problems and has the advantage of using an established system of sample collection. Controversy exists as to the method of choice for analysis of dried samples, this study of 2406 samples found that Iso-electric focusing (IEF) analysis of dried specimens gives excellent correlation when compared with cellulose acetate/citrate agar electrophoresis of liquid cord blood samples. The IEF results were clear and relatively simple to interpret even when the samples had been stored at room temperature for 4 weeks. The commercial enzyme linked immunosorbent assay (ELISA) screening test JOSHUA reliably determines the presence or absence of haemoglobin S in dried specimens. It could therefore be used as a relatively cheap and simple method for the confirmation of sickle cell trait in neonatal screening programmes based on dried specimens.

Plant regeneration from protoplasts of embryogenic suspension cultures of orchardgrass (Dactylis glomerata L.).

An embryogenic suspension culture of orchardgrass (Dactylis glomerata L.) consisting of small, embryogenic cell clusters was obtained from callus formed on basal sections of young leaves through a process of selective enrichment. These suspensions were used as a source of protoplasts. The isolated protoplasts divided at a frequency of 0.5-10% when plated in an agarose solidified culture medium. Conditioned medium, in which embryogenic Dactylis suspension cultures had been grown, was found to increase the rate of cell colony formation. Protoplast-derived colonies grew rapidly in a bead-type culture system of floating agarose slabs in liquid medium. New suspension cultures formed as the colonies grew out of the agarose. These cultures were embryogenic and formed green plantlets when plated on a solid medium lacking auxin. The plantlets were established in soil and grown to mature plants.

Transgenic plants of Orchardgrass (Dactylis glomerata L.) from protoplasts.

We have demonstrated the transfer and expression of a foreign chimeric gene in the grass species, Dactylis glomerata L. This species is a member of the Gramineae sub-family Pooideae, which includes the small grain cereals, from which transformed plants have not yet been obtained. A chimeric hygromycin-resistance gene was introduced into protoplasts isolated from an embryogenic suspension culture, using heat shock followed by electroporation or polyethylene glycol treatment. Cell colonies resistant to 20 µg/ml hygromycin were selected in liquid medium using an agarose bead type culture system. Transformed calli were identified by Southern hybridization. Embryogenic callus was induced to regenerate plants and transformed plants were shown to contain the hygromycin resistance gene.

Gall stones in sickle cell disease in the United Kingdom.

The prevalence of gall stones was studied prospectively by abdominal ultrasound examination in 131 patients with sickle cell disease aged 10-65 years. Of 95 patients with homozygous sickle cell disease, 55 (58%) had gall stones or had had a cholecystectomy. Gall stones were present in four out of 24 (17%) patients with haemoglobin S + C disease and two out of 12 (17%) with haemoglobin S beta thalassaemia. The presence of gall stones was not related to sex, geographical origin, or haematological variables and was not associated with abnormal results of liver function tests. Symptoms typical of biliary colic were reported by 32 out of 47 adult patients with gall stones, and cholecystitis or cholestasis was diagnosed in 18. Cholecystectomy was performed in 29 patients with good relief of symptoms in most cases. Postoperative complications were common, occurring in 10 of the 28 patients who could be evaluated, but not generally serious; they were considerably lessened by a preoperative exchange transfusion that reduced the haemoglobin S concentration to below 40%. It is suggested that all patients with sickle cell disease should be screened for gall stones and that elective cholecystectomy should be performed in those with symptoms or complications.

An investigation of verbal interaction, knowledge of sexual behavior and self-concept in adolescent mothers.

Variables commonly considered to be major factors in contributing to the incidence of adolescent pregnancy may be only part of the total pattern. This study sought to examine the adolescent mothers' communication with significant others and their knowledge about sex, pregnancy, and birth control methods. Self-concepts of the adolescent mothers were compared with those of the published norms of the Tennessee Self-Concept Scale. The study included 23 adolescent mothers between the ages of 13 and 19 who were gravida 1 as indicated by their medical records. They were given a questionnaire constructed from previous research. They also completed a communication scale and the Tennessee Self-Concept Scale. The findings of the present study indicated that most adolescent mothers considered their communication with their parent mothers to be one of mutual understanding. However, it appears that most adolescent mothers obtain much of their information about sex, pregnancy, and birth control methods from significant others. The self-concepts of these adolescent mothers were lower in comparison to the norm. The results indicate a need for further research in the area of adolescent sexual development, sex education in the school, and increased involvement of parents in the communication of sexual mores.

PIP: This study of 23 US adolescent mothers (AM) between the ages of 13 and 19 showed that many of the variables thought to be major factors contributing to the incidence of adolescent pregnancy such as severe life crises, promiscuity, and lack of knowledge about birth control, may be only part of the total pattern. This study sought to examine the AM's communication with their mothers, their friends, and their significant others, and their knowledge about sex, pregnancy, and birth control methods. Self-concepts of the AMs were compared with those of the published norms of the Tennessee Self-Concept Scale. The findings indicated that while most AMs considered their communication with their parent mothers to be one of mutual understanding, most of the AMs obtained much of their information about sex, pregnancy, and birth control from friends and significant others. The self-concepts of these AMs were lower in comparison to the norm. The results indicate a need for further research in the area of adolescent sexual development, sex education in the school, and increased involvement of parents in the communication of sexual mores.

Neonatal screening for sickle cell diseases in Camberwell: results and recommendations of a two year pilot study.

The sickle cell diseases are a major health problem for Afro-Caribbean peoples. Neonatal detection and prophylactic management can reduce mortality and morbidity in childhood. A study was therefore conducted analysing the results of the first two years of cord blood screening in the Camberwell health area. Thirteen cases of sickle cell disease and two of haemoglobin (Hb)C disease were identified among 2202 non-white infants screened. The carrier state, sickle cell trait (HbAS), was present in 11.9% and HbC trait (HbAC) in 4.1% of Afro-Caribbean infants. The incidence of disease and of carrier states was much higher in West Africans than in Caribbeans. The wider implications of screening and the need for a comprehensive plan of care are emphasised.

Photoautotrophic growth of soybean cells in suspension culture: I. Establishment of photoautotrophic cultures.

Highly chlorophyllous photomixotrophic callus was visually selected from callus originating from soybean (Glycine max (L.) Merr. var. Corsoy) cotyledon. Suspension cultures initiated from this callus became photoautotrophic under continuous light with an atmosphere of 5% CO(2) (balance air). Dry weight increases of 1000 to 1400% in the 2-week subculture period have been observed. The cellular Chl content ranged from 4.4 to 5.9 micrograms per milligram dry weight which is about 75 to 90% of the Chl content in soybean leaves under equivalent illumination (300 micro-Einsteins per square meter per second).No growth can be observed in the dark in sucrose-lacking medium or in the presence of 0.5 micromolar 3-(3,4-dichlorophenyl)-1,1-dimethylurea, a concentration which does not inhibit heterotrophic growth (on sucrose). Photoautotrophic growth has an absolute requirement for elevated CO(2) concentrations (>1%). During the 14-day subculture period, growth (fresh weight and dry weight) is logarithmic. Photosynthesis quickly increases after day 4, reaching a peak of 83 micromoles CO(2) incorporated per milligram Chl per hour while dark respiration decreases 90% from day 2 to day 6. The pH of the growth medium quickly drops from 7.0 to 4.5 before slowly increasing to 5.0 by day 14. At this pH range and light intensity (200-300 microEinsteins per square meter per second), no O(2) evolution could be detected although at high pH and light intensity O(2) evolution was recorded.

Cyanide-Resistant Respiration in Suspension Cultured Cells of Nicotiana glutinosa L.

The respiration of dark-grown Nicotiana glutinosa L. cells in liquid suspension culture was found to be highly cyanide resistant and salicylhydroxamic acid (SHAM) sensitive, indicative of an active alternative respiratory pathway. This was especially true during the lag and logarithmic phases of the 14-day growth cycle. Mitochondria isolated from logarithmically growing cells exhibited active oxidation of malate, succinate, and exogenous NADH. Oxidation of all three substrates had an optimum pH of 6.5 and all were highly resistant to inhibited by cyanide and sensitive to SHAM. Respiratory control was exhibited by all three substrates but only if SHAM was present to block the alternative pathway and divert electrons to the phosphorylating cytochrome pathway. The cyanide-resistant oxidation of exogenous NADH has previously only been associated with Arum spadix mitochondria. Coemergence during evolution of the alternative respiratory pathway and the exogenous NADH dehydrogenase in plant mitochondria as a possible mechanism for removal of cytoplasmic NADH is proposed. Evidence is presented which suggests that mitochondrial assays should be performed at pH 6.5.

Genetic factors in childhood asthma.

The prevalences of asthma and atopy were examined in the families of 77 asthmatic and 87 control children attending a London general practice. The prevalence of asthma in first degree relatives of asthmatic children was found to be significantly higher than in relatives of control children, and this difference was more pronounced for relatives of atopic probands than for relatives of non-atopic probands. Among the relatives of asthmatics, atopic asthma was more common than non-atopic asthma, irrespective of the atopic status of the proband. However, among the relatives of control children, neither the prevalence of asthma nor the atopic status of the asthmatic relatives was influenced by the atopic status of the proband. These findings support the hypothesis that asthma and atopy are inherited independently. Although atopy itself does not predispose to asthma, it may enhance a genetic susceptibility to the condition, thus increasing the likelihood that the latter will be expressed.

A family study of the genetic basis of asthma and wheezy bronchitis.

The family histories relating to asthma and wheezy bronchitis were examined in 77 asthmatic, 78 wheezy bronchitic, and 87 control children, aged between 1 and 12 years. The percentage of children with at least one asthmatic relative was significantly greater in the asthmatic and wheezy bronchitic probands than in the controls; and asthma was more prevalent in the relatives of both groups of wheezy probands than in the relatives of controls. Similarly, the percentage of children with at least one wheezy bronchitic relative tended to be greater in asthmatic and wheezy bronchitic probands than in the controls; and wheezy bronchitis tended to be more prevalent in the relatives of both groups of wheezy probands than in the relatives of controls. However these differences did not reach significance. The strong similarities between asthmatic and wheezy bronchitic children in their family histories of asthma and wheezy bronchitis suggest that these two forms of wheezy illness share a common genetic defect.

Role of viruses and bacteria in acute wheezy bronchitis in childhood: a study of sputum.

Sputum, nasal swabs, and throat swabs were obtained from 22 children aged between 5 and 15 years during 72 attacks of wheezy bronchitis. A virus, most commonly a rhinovirus, was isolated in 49% of all episodes and in 64% of 22 severe episodes requiring treatment with corticosteroids; the isolation rate was higher early in the illness than later. Virus was recovered more often from sputum than from the nose or throat, suggesting that viral replication occurs freely in the lower respiratory tract: the cytological findings in sputum were compatible with an inflammatory response to viral infection. Pathogenic bacteria appeared to play a minor role compared with viruses, and routine antibiotic treatment was probably of little value in moost cases. The significance of the results is discussed in relation to the pathogenesis of childhood wheezy bronchitis.

Respiratory viral infection and wheezy bronchitis in childhood.

The role of respiratory viral infection in wheezy bronchitis was studied in 163 children, aged 0-12 years, in a London general practice. Virological investigations were also performed when these same children had acute upper respiratory illness without wheeze. A virus was isolated in 146 (26.4%) of 554 episodes of wheezy bronchitis, rhinoviruses accounting for almost half of the isolations. The relative frequency with which individual viruses were isolated in wheezy bronchitis was similar to that in acute upper respiratory illness in 180 other children who had never had wheezy bronchitis. The large number of isolations of rhinoviruses in wheezy bronchitis is probably due to their numerous serotypes and the absence of cross-immunity between them. Our findings have confirmed that infection by respiratory viruses can provoke wheezy bronchitis in certain children, in whom host factors are an important predeterminant. In children with a previous history of wheezy bronchitis infection by rhinoviruses was associated significantly more often with such an episode than with upper respiratory illness. The maturation of protective mechanisms, including the acquisition of specific immunity to a progressively larger number of viruses, could explain the fall in the age-incidence of wheezy bronchitis.

Respiratory viral infection in childhood. A survey in general practice, Roehampton 1967-1972.

The role of viruses and M. pneumoniae in episodes of acute respiratory illness in childhood has been studied in a London general practice. The total isolation rate was 31-7 per cent, but the rate varied from 32-6 per cent in upper respiratory infections to 64-0 per cent in pneumonia. The clinical features associated with infection were influenced not only by the type of agent but also by age and other host factors in infected children. Rhinoviruses were more commonly isolated than any other agent and were frequently associated with wheezy bronchitis.