Morphoea and Borrelia burgdorferi: results from the Scottish Highlands in the context of the world literature.

AIMS: Previous studies investigating the link between infection with Borrelia burgdorferi and morphoea have produced conflicting results. Often, these studies have been undertaken in patients from different regions or countries, and using methods of varying sensitivity for detecting Borrelia burgdorferi infection. This study aimed to establish whether a relation could be demonstrated in the Highlands of Scotland, an area with endemic Lyme disease, with the use of a sensitive method for detecting the organism. METHODS: The study was performed on biopsies of lesional skin taken from 16 patients from the Highlands of Scotland with typical clinical features of morphoea. After histological confirmation of the diagnosis, a nested polymerase chain reaction (PCR) using primers to a unique conserved region of the Borrelia burgdorferi flagellin gene was performed on DNA extracts from each biopsy. A literature search was also performed for comparable studies. RESULTS: None of the 16 patients had documented clinical evidence of previous infection with B burgdorferi. DNA was successfully extracted from 14 of the 16 cases but all of these were negative using PCR for B burgdorferi specific DNA, despite successful amplification of appropriate positive controls in every test. The results were compared with those of other documented studies. CONCLUSIONS: Examination of the literature suggests that there is a strong geographical relation between B burgdorferi and morphoea. These results, in which no such association was found, indicate that morphoea may not be associated with the subspecies of B burgdorferi found in the Highlands of Scotland.     

Properties of implanted electrodes for functional electrical stimulation

Implanted wire electrodes are increasingly being used for the functional electrical stimulation of muscles in partially paralysed patients, yet many of their basic characteristics are poorly understood. In this study we investigated the selectivity, recruitment characteristics and range of control of several types of electrode in triceps surae and plantaris muscles of anaesthetized cats. We found that nerve cuffs are more efficient and selective (i.e., cause less stimulus spread to surrounding muscles) than intramuscular electrodes. Bipolar intramuscular stimulation was more efficient and selective than monopolar stimulation, but only if the nerve entry point was between the electrodes. Monopolar electrodes are efficient and selective if located close to the nerve entry point, but their performance declines with distance from it. Nonetheless, for a variety of reasons monopolar stimulation provides the best compromise in many current applications. Short duration pulses offer the best efficiency (least charge per pulse to elicit force) but high peak currents, increasing the risk of electrode corrosion and tissue damage. Electrode size has little effect on recruitment and should therefore be maximised because this minimises current density.     

HnRNP CBP35-CBP67 interaction during stress response and ageing

Previous studies have demonstrated the existence of nuclear carbohydrate binding proteins in a variety of mammalian cells with molecular masses of 35 000, 67 000, and 70 000 (CBP35, CBP67, and CBP70), which are associated with nuclear ribonucleoprotein (RNP) complexes. CBP35 consists of two domains, an aminoterminal portion that is homologous to certain regions of proteins of the heterogeneous nuclear RNP complex, and a carboxyl-terminal portion homologous to β-galactoside-specific lectins. CBP35 it has been proposed, like the glucose-specific lectin, CBP67, to guide RNP complexes through the nuclear pore. Here we show that the exposure of mature rats to stress induces an increase in nuclear CBP35 bound to CBP67 and retained on immobilized glucose. Nuclear extracts from the livers of old rats displayed no detectable stress response. This CBP35·CBP67 association detected in rat liver is considered with respect to the CBP35·CBP70 association recently observed in HL60 cell nuclear extracts.     

Exposure-response relationships for work-related sensitization in workers exposed to rat urinary allergens: results from a pooled study

BACKGROUND: Recent studies in a few industries have shown that the likelihood of IgE-mediated sensitization increases with increasing exposure. The shape of the exposure-response relationships and modification by age, sex, and smoking habit has hardly been studied. OBJECTIVE: The purpose of this study was to determine exposure sensitization relationships for rat sensitization and to evaluate the influence of atopy, smoking habits, and sex. METHODS: Data from 3 cross-sectional studies in The Netherlands, the United Kingdom, and Sweden were used and involved 1062 animal laboratory workers. Selection criteria were harmonized, and this resulted in a study population of 650 animal laboratory workers (60.6% female) with less than 4 years of exposure. Air allergen levels were assessed previously and converted on the basis of an interlaboratory allergen analysis comparison. Available sera were analyzed for the presence of specific antibodies against common allergens (house dust mite, cat, dog, and grass and birch pollen) and work-related allergens (rat and mouse urinary proteins). Questionnaire items on work-related respiratory symptoms, hours worked with rats per week, job performed, smoking habits, and sex were used in this analysis RESULTS: The prevalence of work-related sensitization to rat urinary allergens (IgE >0.7 KU/L) was 9.7 % (n = 63). Thirty-six of the sensitized workers had work-related symptoms (asthma or rhinitis). Two hundred forty-eight workers (38.2%) were atopic (defined as specific IgE to 1 of the common allergens). The sensitization rate increased with increasing air allergen exposure. Atopic workers exposed to low levels of allergen had a more than 3-fold increased sensitization risk compared with nonexposed atopic workers. For atopic subjects, the risk increased little with increasing exposure, whereas for nonatopic subjects, a steadily increasing risk was observed. Smoking and sex did not modify the sensitization risk. CONCLUSION: Rat urinary allergen-sensitization risk increased with increasing exposure intensity. Workers who were atopic had a clearly elevated sensitization risk at low allergen exposure levels.     

QUANTIFICATION OF THE REM SLEEP CYCLE AS A RHYTHM

The goal of this study was to develop an objective quantitative method for representing the temporal organization of sleep in terms of the period and rhythmicity of REM sleep occurrences. Data on normative human sleep, already scored for stage REM and not stage REM, were subjected to a “binary autocorrelation.” The mean period over 92 nights of sleep for 10 Ss was 101.5 min and quite stable. Data is also presented on variability of the rhythm in terms of an “index of rhythmicity.” Measures of temporal organization may prove to be as significant for sleep research as amount of the various sleep stages.     

The variation in isometric tension with sarcomere length in vertebrate muscle fibres

1. The variation of isometric tetanus tension with sarcomere length in single fibres from frog striated muscle has been re-investigated with special precautions to ensure uniformity of sarcomere length within the part of the fibre being studied.2. In most respects the results of Ramsey & Street (1940) were confirmed, but (a) the peak of the curve was found to consist of a plateau between sarcomere lengths of 2.05 and 2.2 mu, (b) the decline of tension above this plateau is steeper than found by Ramsey & Street, and (c) the decline of tension below the plateau becomes suddenly steeper at a sarcomere length of about 1.67 mu.3. Many features of this length-tension relation are simply explained on the sliding-filament theory.4. It is concluded that, in the plateau and at greater lengths, the tension on each thin filament is made up of equal contributions from each bridge which it overlaps on adjacent thick filaments.5. Internal resistance to shortening is negligible in this range but becomes progressively more important with shortening below the plateau.     

Rapid presumptive identification of streptococci directly from blood cultures by serologic tests and the L-pyrrolidonyl-beta-naphthylamide reaction.

The value of the Strepslide kit for the rapid presumptive identification of streptococci directly from blood cultures without prior determination of hemolysis patterns was assessed and compared with that of the Streptex and Phadebact streptococcus kits. Studies involved 94 simulated and 60 clinical isolates of 83 streptococci. The Streptex and Strepslide kits had excellent sensitivity and specificity for group A, B, F, and G organisms, and the Phadebact kit had excellent sensitivity and specificity for groups B and G. Group C reactions usually occurred with all of the streptococcus kits with pneumococci and occasionally with alpha-hemolytic streptococci. Although these kits were unacceptable for group C and D organisms, enterococci which were common clinical isolates could be directly identified in blood cultures by a supplementary rapid L-pyrrolidonyl-beta-naphthylamide biochemical test. Direct application of the Phadebact pneumococcus kit to blood cultures was also assessed with 29 isolates of 20 organisms. The specificity was good, but the sensitivity was only 65.5%.     

Delayed angiogenesis in aging rats and therapeutic effect of adenoviral gene transfer of VEGF

We have studied an age-related impairment in angiogenesis and evaluated the effect of overexpressing VEGF in this situation. Polyvinyl alcohol sponges were implanted subcutaneously into aged (24-month), adult (12-month), and young (2-month) rats. Blood vessel ingrowth and proliferative activity in the sponges were assessed by histology with immunostaining for von Willebrand's factor and proliferating cell nuclear antigen (PCNA), respectively. The percentage of total sponge area filled with ingrowing fibrovascular tissue was minimal in aged rats, intermediate in adult rats and highest in young rats. A similar pattern was observed for the total blood vessel numbers in the sponges from old to young animals. The percentage of total sponge endothelial cells (ECs) showing proliferative activity (PCNA positive) was lowest in the aged animals, intermediate in the adult rats and highest in the young rats. To further explore the mechanism of impaired angiogenesis in aged animals, we investigated and found a reduced level of endogenous VEGF protein expression in 12-month-old rats compared to that in 2-month-old rats. VEGF121 gene transfer significantly enhanced blood vessel and fibrovascular tissue ingrowth in adult/aged rats. Adenoviral-VEGF gene transfer also significantly stimulated EC proliferation in aged and adult rats. However, identical treatment failed to further stimulate the already more robust angiogenesis in young animals. The different angiogenic response in adult vs. young rats was not due to differences in gene transfer efficiency, since similar levels of human VEGF121 protein was detected in adult and young rats. Our results indicate that the decreased angiogenic response with aging is associated with reduced EC proliferation and reduced endogenous VEGF production. Adenoviral-VEGF121 gene transfer is effective in augmenting angiogenesis, particularly in older animals.