Improved method robustness and ruggedness in liquid chromatography-mass spectrometry by increasing the acid content of the mobile phase

A routine multiresidue method developed for the detection and quantification of veterinary drug residues in animal-based food was used to analyze sheep (ovine) liver. Unlike when working with previously validated matrices (e.g., bovine liver), some of the analytes of interest chromatographed in the form of split- or even fully baseline separated peaks. In other cases a significantly longer retention times (tR) was observed. A detailed investigation led to the elucidation of taurocholic acid as the causative agent. This compound is present in sheep liver at significantly higher concentrations than in most other animal tissues. Taurocholic acid is a zwitterionic compound and likely acts as an ion pairing agent, which modifies the selectivity of the stationary phase in a highly spatial and dynamic way. Injecting smaller volumes of matrix extract or the use of a significantly higher formic acid concentration in the mobile phase reduced or even completely eliminated the peak splitting. A more detailed examination led to the observation that the problem is not restricted to this particular matrix and extraction procedure or the used stationary phase. In fact, a higher formic acid concentration (e.g., 1.0 % versus 0.1 %) significantly improves the peak shape of many analytes present in fortified matrix samples as well as in pure standard solutions. In addition, analytical column aging was observed as being slower with a higher formic acid concentration. Finally the peak shape of analytes interacting with the metallic parts along the flow path of the liquid chromatograph was also significantly improved. Use of 0.1 % acid in mobile phases is often taken for granted in LC-MS. Regardless of the stationary phase, a higher ionic strength better stabilizes the pH and reduces unwanted interactions, which ultimately improves the method robustness. Flow injection experiments often show that 0.1 % acid concentrations produce the highest analyte signals. Yet, the use of 1 % acid in the mobile phase often leads to narrower and therefore taller chromatographic peaks, which may lead to lower detection limits for many analytes and to an improved separation efficiency.

Optimized multimatrix calibration concept for liquid chromatography mass spectrometry-based bioanalysis methods

In this paper, a calibration procedure for LC/MS-based bioanalysis methods, termed "A/B fortification", is proposed. The concept relies on the post-extraction fortification (B-spike) of an aliquot of the injection-ready sample extract for the determination and compensation of specific signal suppression or enhancement effects compared to matrix-free extract prepared in buffer or mobile phase. Conventional analyte recovery, observed due to the incomplete extraction of analytes from the sample or losses during a cleanup, is determined by the conventional pre-extraction fortification (A-spike) of a blank sample that belongs to the same type of matrix as the sample with the unknown analyte concentration. This approach permits a higher throughput than conventional sample fortification strategies. The results obtained by utilizing the A/B fortification concept were extensively compared against conventional methods (representative bank matrix fortification, sample fortification and internal standard). The proposed concept (based on the pre-fortification of a reference matrix and post-fortification of the sample) was found to be significantly less biased than internal standard-based techniques. The A/B fortification indicated a better accuracy than the sample fortification or representative blank matrix fortification approach and, most importantly, produced significantly fewer outliers. This was linked to the fact that in the case of the A/B fortification, the uncertainty of the subtraction of two peak areas (fortified minus unfortified sample) is reduced, because fortifications are not made prior to the extraction step but are made into the final injection-ready sample extract. Fortification into an injection-ready aliquot eliminates all sample processing-related differences (procedural errors), which can affect conventional sample fortification-based quantifications.

PCR for the detection of pathogens in neonatal early onset sepsis

Background

A large proportion of neonates are treated for presumed bacterial sepsis with broad spectrum antibiotics even though their blood cultures subsequently show no growth. This study aimed to investigate PCR-based methods to identify pathogens not detected by conventional culture.

Methods

Whole blood samples of 208 neonates with suspected early onset sepsis were tested using a panel of multiplexed bacterial PCRs targeting Streptococcus pneumoniae, Streptococcus agalactiae (GBS), Staphylococcus aureus, Streptococcus pyogenes (GAS), Enterobacteriaceae, Enterococcus faecalis, Enterococcus faecium, Ureaplasma parvum, Ureaplasma urealyticum, Mycoplasma hominis and Mycoplasma genitalium, a 16S rRNA gene broad-range PCR and a multiplexed PCR for Candida spp.

Results

Two-hundred and eight samples were processed. In five of those samples, organisms were detected by conventional culture; all of those were also identified by PCR. PCR detected bacteria in 91 (45%) of the 203 samples that did not show bacterial growth in culture. S. aureus, Enterobacteriaceae and S. pneumoniae were the most frequently detected pathogens. A higher bacterial load detected by PCR was correlated positively with the number of clinical signs at presentation.

Conclusion

Real-time PCR has the potential to be a valuable additional tool for the diagnosis of neonatal sepsis.

Reliability of veterinary drug residue confirmation: high resolution mass spectrometry versus tandem mass spectrometry

Confirmation of suspected residues has been a long time domain of tandem triple quadrupole mass spectrometry (QqQ). The currently most widely used confirmation strategy relies on the use of two selected reaction monitoring signals (SRM). The details of this confirmation procedure are described in detail in the Commission Decision 93/256/EC (CD). On the other hand, high resolution mass spectrometry (HRMS) is nowadays increasingly used for trace analysis. Yet its utility for confirmatory purposes has not been well explored and utilized, since established confirmation strategies like the CD do not yet include rules for modern HRMS technologies. It is the focus of this paper to evaluate the likelihood of false positive and false negative confirmation results, when using a variety of HRMS based measurement modes as compared to conventional QqQ mass spectrometry. The experimental strategy relies on the chromatographic separation of a complex blank sample (bovine liver extract) and the subsequent monitoring of a number of dummy transitions respectively dummy accurate masses. The term "dummy" refers to precursor and derived product ions (based on a realistic neutral loss) whose elemental compositions (CxHyNzOdCle) were produced by a random number generator. Monitoring a large number of such hypothetical SRM's, or accurate masses inevitably produces a number of mass traces containing chromatographic peaks (false detects) which are caused by eluting matrix compounds. The number and intensity of these peaks were recorded and standardized to permit a comparison among the two employed MS technologies. QqQ performance (compounds which happen to produce a response in two SRM traces at identical retention time) was compared with a number of different HRMS(1) and HRMS(2) detection based modes. A HRMS confirmation criterion based on two full scans (an unfragmented and an all ion fragmented) was proposed. Compared to the CD criteria, a significantly lower probability of false positive and false negative findings is obtained by utilizing this criterion.

Characterisation of bovine leukocyte Ig-like receptors

Leukocyte Immunoglobulin-like receptors (LILR) are innate immune receptors involved in regulating both innate and adaptive immune functions. LILR show more interspecies conservation than the closely related Killer Ig-like receptors, and homologues have been identified in rodents, primates, seals and chickens. The murine equivalents, paired Ig-like receptors (PIR), contain two additional immunoglobulin domains, but show strong sequence and functional similarities to human LILR. The bovine genome was recently sequenced, with preliminary annotations indicating that LILR were present in this species. We therefore sought to identify and characterize novel LILR within the Bos taurus genome, compare these phylogenetically with LILR from other species and determine whether they were expressed in vivo. Twenty six potential bovine LILR were initially identified using BLAST and BLAT software. Phylogenetic analysis constructed using the neighbour-joining method, incorporating pairwise deletion and confidence limits estimated from 1000 replicates using bootstrapping, indicated that 16 of these represent novel bovine LILR. Protein structures defined using protein BLAST predict that the bovine LILR family comprises seven putative inhibitory, four activating and five soluble receptors. Preliminary expression analysis was performed by mapping the predicted sequences with raw data from total transcript sequence generated using Genome Analyzer IIx (Illumina) to provide evidence that all 16 of these receptors are expressed in vivo. The bovine receptor family appears to contain receptors which resemble the six domain rodent PIR as well as the four domain LILR found in other species.

Development of an improved high resolution mass spectrometry based multi-residue method for veterinary drugs in various food matrices

Multi-residue methods for veterinary drugs or pesticides in food are increasingly often based on ultra performance liquid chromatography (UPLC) coupled to high resolution mass spectrometry (HRMS). Previous available time of flight (TOF) technologies, showing resolutions up to 15,000 full width at half maximum (FWHM), were not sufficiently selective for monitoring low residue concentrations in difficult matrices (e.g. hormones in tissue or antibiotics in honey). The approach proposed in this paper is based on a single stage Orbitrap mass spectrometer operated at 50,000 FWHM. Extracts (liver and kidney) which were produced according to a validated multi-residue method (time of flight detection based) could not be analyzed by Orbitrap because of extensive signal suppression. This required the improvement of established extraction and clean-up procedures. The introduced, more extensive deproteinzation steps and dedicated instrumental settings successfully eliminated these detrimental suppression effects. The reported method, covering more than 100 different veterinary dugs, was validated according to the EU Commission Decision 2002/657/EEC. Validated matrices include muscle, kidney, liver, fish and honey. Significantly better performance parameters (e.g. linearity, reproducibility and detection limits) were obtained when comparing the new method with the older, TOF based method. These improvements are attributed to the higher resolution (50,000 versus 12,000 FWHM) and the superior mass stability of the of the Orbitrap over the previously utilized TOF instrument.

Benzothiazinones kill Mycobacterium tuberculosis by blocking arabinan synthesis

New drugs are required to counter the tuberculosis (TB) pandemic. Here, we describe the synthesis and characterization of 1,3-benzothiazin-4-ones (BTZs), a new class of antimycobacterial agents that kill Mycobacterium tuberculosis in vitro, ex vivo, and in mouse models of TB. Using genetics and biochemistry, we identified the enzyme decaprenylphosphoryl-beta-d-ribose 2'-epimerase as a major BTZ target. Inhibition of this enzymatic activity abolishes the formation of decaprenylphosphoryl arabinose, a key precursor that is required for the synthesis of the cell-wall arabinans, thus provoking cell lysis and bacterial death. The most advanced compound, BTZ043, is a candidate for inclusion in combination therapies for both drug-sensitive and extensively drug-resistant TB.

Cytokine mRNA expression in Mycobacterium ulcerans-infected human skin and correlation with local inflammatory response

Cytokine mRNA expression in biopsies of Mycobacterium ulcerans-infected human tissue was investigated using real-time PCR, and the findings were correlated with the clinical stages of disease and histopathologies. A broad range of cytokine mRNAs were detected in 16 early nodules and 28 late-stage ulcers, including those for the Th1 cytokines tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) and the Th2 cytokine interleukin 10 (IL-10). IFN-gamma was strongly expressed in both nodules and ulcers, suggesting that a Th1 response begins early in the disease. There was a significantly higher expression of IL-8 and other proinflammatory cytokines in results from 32 biopsies with neutrophilia than in those from 12 biopsies without acute inflammation. Ten tissue samples containing granulomas showed high mRNA expression for IFN-gamma, IL-1beta, IL-12p35, IL-12p40, IL-15, and TNF-alpha relative to 34 tissue samples without granulomas. These results suggest that the human immune response to M. ulcerans is similar to that seen with some other mycobacteria despite the presence of the toxin mycolactone in the tissues.

Advanced significance analysis of microarray data based on weighted resampling: a comparative study and application to gene deletions in Mycobacterium bovis

MOTIVATION

When analyzing microarray data, non-biological variation introduces uncertainty in the analysis and interpretation. In this paper we focus on the validation of significant differences in gene expression levels, or normalized channel intensity levels with respect to different experimental conditions and with replicated measurements. A myriad of methods have been proposed to study differences in gene expression levels and to assign significance values as a measure of confidence. In this paper we compare several methods, including SAM, regularized t-test, mixture modeling, Wilk's lambda score and variance stabilization. From this comparison we developed a weighted resampling approach and applied it to gene deletions in Mycobacterium bovis.

RESULTS

We discuss the assumptions, model structure, computational complexity and applicability to microarray data. The results of our study justified the theoretical basis of the weighted resampling approach, which clearly outperforms the others.

Evolutionary relationships among strains of Mycobacterium tuberculosis with few copies of IS6110

Molecular typing of Mycobacterium tuberculosis by using IS6110 shows low discrimination when there are fewer than five copies of the insertion sequence. Using a collection of such isolates from a study of the epidemiology of tuberculosis in London, we have shown a substantial degree of congruence between IS6110 patterns and both spoligotype and PGRS type. This indicates that the IS6110 types mainly represent distinct families of strains rather than arising through the convergent insertion of IS6110 into favored positions. This is supported by identification of the genomic sites of the insertion of IS6110 in these strains. The combined data enable identification of the putative evolutionary relationships of these strains, comprising three lineages broadly associated with patients born in South Asia (India and Pakistan), Africa, and Europe, respectively. These lineages appear to be quite distinct from M. tuberculosis isolates with multiple copies of IS6110.

Estimation of the rate of unrecognized cross-contamination with mycobacterium tuberculosis in London microbiology laboratories

Isolates from patients with confirmed tuberculosis from London were collected over 2.5 years between 1995 and 1997. Restriction fragment length polymorphism (RFLP) analysis was performed by the international standard technique as part of a multicenter epidemiological study. A total of 2,779 samples representing 2,500 individual patients from 56 laboratories were examined. Analysis of these samples revealed a laboratory cross-contamination rate of between 0.54%, when only presumed cases of cross-contamination were considered, and 0.93%, when presumed and possible cases were counted. Previous studies suggest an extremely wide range of laboratory cross-contamination rates of between 0.1 and 65%. These data indicate that laboratory cross-contamination has not been a common problem in routine practice in the London area, but in several incidents patients did receive full courses of therapy that were probably unnecessary.

Diagnosis of Pneumocystis carinii pneumonia: immunofluorescence staining, simple PCR or nPCR

OBJECTIVES

to compare immunofluorescence (IF) test, routinely used in the department for the detection of Pnemocystis carinni with simple polymerase chain reaction (PCR) and nested PCR (nPCR) METHODS: Bronchoalveolar lavage (BAL) and induced sputum (IS) specimens from HIV-positive (39), lung transplant ssart transplant (2), and one each from non-Hodgkin's lymphoma, drug addict and a premature baby were screened by IF test, simple PCR and nPCR for the presence of P.carinii.

RESULTS

of the 46 specimens tested, two (4.3%) were positive by IF, 11 (23.9%) by simple PCR and 21 (45.6%) by nPCR. Both simple and nPCR amplified those found positive by IF test. Analysis of the clinical data revealed both IF positive, 10 of the simple PCR and 15 of the nPCR group were strongly suspected of P. carinii pneumonia (PCP). Two specimens, one from a patient where chest X-ray was suggestive of PCP and the other where post-mortem histology revealed the presence of PCP, were negative by IF test.

CONCLUSION

simple PCR detection may be considered for patients where PCP is suggestive clinically and the specimen is negative by IF test.

Psychological processes in psychogenic voice disorder

Using Freud's hysterical conversion model as a basis for reviewing the psychological features in psychogenic voice disorder, this paper describes research findings which show that individuals with this condition are not usually suffering from severe psychopathology but tend to be women who are experiencing high levels of stress (commonly associated with interpersonal relationship conflicts, low self-esteem, the burden of responsibility and feelings of powerlessness), and have above-average musculoskeletal tension as well as difficulties in voicing their feelings or views. The review indicates that the psychoanalytic interpretation of psychogenic voice loss continues to have relevance. However, it is suggested that in most cases Freud's hysterical conversion model should be reformulated, reducing the core focus to unconscious conflicts, repression, denial and secondary gains, in order to emphasise the psychosocial causes and maintenance of intrapsychic conflict and physical dysfunction. It is also suggested that a reformulated psychoanalytic interpretation of psychogenic voice loss has a lot in common with a cognitive-behavioural conceptual model. A psychoanalytic approach may be valuable when focused on early trauma and repressed experiences or feelings, whereas cognitive-behavioural treatment strategies, such as stress management and assertiveness training, appear to be particularly relevant in this condition. The paper concludes by briefly considering some areas of future research.

Association of cytomegalovirus infection with post-transplantation cardiac rejection as studied using the polymerase chain reaction

The relationship between cytomegalovirus (CMV) infection and cardiac allograft rejection is controversial, some authors reporting a significant association, others not, on the basis of the results of conventional virological diagnosis by culture or serology. This problem was reinvestigated in 88 patients using a semi-quantitative nest polymerase chain reaction (PCR) procedure for detecting CMV DNA in endomyocardial biopsy specimens. Significantly more positive biopsies were obtained from patients with moderate (grade 2; P = 0.02) or severe (grade 3a-4; P = 0.03) rejection than with no or mild (grade 0-1b) rejection, whereas there was no significant association between rejection and CMV as diagnosed by virus isolation from urine, throat or blood, or by the detection of CMV-IgM. PCR-positive biopsies originated most frequently from CMV-antibody positive recipients (R+) of hearts from seropositive donors (D+), in association with moderate or severe rejection rather than with mild or no rejection The detection of CMV in the heart thus seemed to be related more to R+D+ serological status than to severity of rejection, that is, to circumstances that favoured co-infection with strains of CMV from both donor and recipient. Studies on sequential biopsy specimens from selected patients also provided evidence that CMV infection and rejection were not always related events. The PCR was able to differentiate latent from active CMV infection; moreover, some seronegative individuals gave repeatedly positive biopsies, thereby supporting the work of others that some patients undergo CMV infection without mounting a detectable antibody response.(ABSTRACT TRUNCATED AT 250 WORDS)

International social security agreements: the U.S. experience

International social security agreements are advantageous both for persons who are working now and for those whose working careers are over. For current workers, the agreements eliminate the dual contributions they might otherwise be paying to the social security systems of both the United States and another country. They also favorably affect the profitability and competitive position of American companies with foreign operations by reducing their cost of doing business. For persons who have worked both in the United States and abroad, and who are now retired, disabled, or deceased, the agreements often result in the payment of benefits to which the worker or the worker's family members would not otherwise have become entitled. Credit for social security coverage the worker earned in the United States and the other country can be combined, if necessary, to meet eligibility requirements, and partial benefits can be paid by one or both countries. Because international social security agreements benefit both workers and employers, the agreements program is supported by organized labor and the international business community. Since the first agreement was signed 15 years ago, every Presidential administration has endorsed the program. In view of this support, and the fact that the agreements enhance the image of the United States as a socially progressive member of the international community, it is expected that totalization agreements will be concluded with additional countries in the future.

A personal effectiveness and stress management course for community health workers: a pilot study

Since the role of a community health worker in an inner city area is potentially very stressful, there is a requirement to provide help, support and training to enable them to function successfully. An individual who has learned coping skills might also feel confident about teaching these skills to clients. This paper describes a short course intended to enable professionals such as health visitors, speech therapists, community nurses and physiotherapists to cope better with stress and to be more effective in their daily work with colleagues as well as in sharing skills with clients. The initial, actual knowledge of the participant and confidence in perceived knowledge and ability was assessed before and immediately after the training and at a 4-month follow-up and this was replicated in a second nurse. The preliminary results suggested that the course brought about highly significant changes which were generally maintained at follow-up.

The possible involvement of changes in phosphoinositol turnover in the responses of renal sodium transport to noradrenaline

Noradrenaline stimulated the formation of [3H]inositol monophosphates from 3H-inositol-phospholipids in rat kidney cortex slices. This response was inhibited by the alpha 1-adrenoceptor antagonist prazosin but not by the alpha 2-adrenoceptor antagonist yohimbine, suggesting that the response was mediated via an alpha 1-adrenoceptor. This is in keeping with the ability of noradrenaline to increase sodium transport in this tissue by alpha 1-adrenoceptor stimulation.

Baroreflex control of jejunal blood flow and fluid transport in cats; effects of yohimbine, an alpha 2-adrenergic antagonist

The aim of the study was to test the hypothesis that baroreceptor unloading increases jejunal fluid absorption rate via an alpha 2-adrenergic effect on electrogenic active transport. In 13 chloralose-anaesthetized cats, the carotid sinus baroreceptors were isolated and perfused with arterial blood, and we studied the effects of a graded decrease in carotid sinus pressure on intestinal vascular resistance, net fluid absorption rate and the potential difference between the intestinal lumen and the peritoneal cavity (PD). Experiments were performed in seven control animals and in six animals pretreated with yohimbine, an alpha 2-adrenergic antagonist, at a dose of 0.1 mg kg-1 i.v. Yohimbine per se had no significant effects on systemic arterial pressure, intestinal vascular resistance, net fluid absorption rate or PD. In the control animals, baroreceptor unloading induced an increase in systemic arterial pressure, intestinal vascular resistance and net fluid absorption rate, and a decrease in the PD. Yohimbine pretreatment did not significantly affect the systemic blood pressure response to baroreceptor unloading, but abolished the effect on intestinal vascular resistance and PD. After yohimbine treatment, decreases in carotid sinus pressure still enhanced net fluid absorption rate, but this response was observed in a higher range of carotid sinus pressures than in control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrogenic and electroneutral components of the sympathetic effect on fluid absorption in the rat jejunum

The aim of the study was to test the hypothesis that the sympathetic nerves to the jejunum enhance net fluid absorption rate by inhibiting an electrogenic flux of anions into the lumen. The design of the experiments was based on the observation that the effect of catecholamines on electrogenic transport is abolished by yohimbine, an alpha 2 adrenergic antagonist. Net electrogenic transport in jejunal segments of anaesthetized rats was estimated by measurement of the transepithelial potential difference (PD) and short-circuit current (SCC). Net fluid absorption rate was quantified by a gravimetric technique. The sympathetic nerves to the segment were stimulated electrically, both in vitro and in vivo. The effect of sympathetic nerve stimulation on SCC and net fluid transport was determined in the absence and presence of the alpha-adrenergic antagonists phentolamine (a non-selective alpha-adrenergic antagonist), prazosin (a selective alpha 1-antagonist) and yohimbine (a selective alpha 2-antagonist). Sympathetic nerve stimulation decreased PD and SCC and increased net fluid absorption rate. Phentolamine abolished both the electrogenic response and the effect on net fluid absorption rate, without having any significant intrinsic effects on either parameter. Prazosin per se markedly increased net fluid absorption rate, but did not significantly influence the sympathetic effect on SCC or net fluid absorption rate. Yohimbine abolished the electrogenic effect of sympathetic stimulation, and per se increased net fluid absorption rate in innervated but not in denervated segments. In innervated segments, the absorption rate during sympathetic nerve stimulation was similar in controls and yohimbine-treated animals. In denervated segments, yohimbine significantly attenuated the sympathetic response. The results suggest that the sympathetic nerves enhance fluid absorption rate via effects on both electrogenic and electroneutral epithelial transport. These two components of the sympathetic response seem to be mediated by different alpha-receptor mechanisms.

Neural control of electrogenic transport in the rat jejunum; interaction between intramural and adrenergic mechanisms

The aim of the study was to test the hypothesis that extrinsic adrenergic neurons modulate electrogenic ion transport in the jejunum by inhibition of intramural secretory nerve activity. Isolated pieces of rat jejunum were mounted in the Ussing chamber. Noradrenaline (NA) was released from sympathetic nerve endings in the tissue by electrical stimulation of the mesenteric nerves or by the indirect sympathomimetic agent tyramine. Intramural neurons were activated by electrical field stimulation (EFS). Mesenteric nerve stimulation induced a frequency-related decrease in the transepithelial potential difference (PD) and short circuit current (SCC), effects which were abolished by the alpha-adrenergic antagonist phentolamine. A similar response was induced by the serosal application of tyramine and by exogenous NA. Tetrodotoxin (TTX), a nerve conduction inhibitor, had no significant effect on the response to NA, but attenuated the response to tyramine. Both NA and tyramine markedly attenuated the secretory response to EFS, but there was no significant effect of catecholamines on the secretory response to serosal theophylline. The results suggest at least two mechanisms behind the adrenergic modulation of electrogenic chloride secretion: (I) a ganglionic or presynaptic modulation of secretory nerve activity via innervated alpha-receptors, and (2) a modulation at the level of the enterocytes via non-innervated alpha-receptors. The latter effect does not seem to be mediated by the cAMP system.

Cardiac receptor modulation of blood flow and fluid transport in feline jejunum

The aim of the study is to determine the effects of selective cardiac receptor unloading on vascular resistance and net fluid transport in the small intestine. In anesthetized cats, cardiac receptors were unloaded by positive pressure ventilation (PPV). Arterial baroreceptor activity was artificially maintained constant. To test if the observed responses were due to a vagal reflex, experiments were performed both in animals with intact vagal nerves (n = 9) and after bilateral cervical vagotomy (n = 8). PPV-induced decreases in central blood volume (CBV) significantly increased intestinal vascular resistance (IVR) and net fluid absorption rate and decreased the transmural potential difference (PD). Cervical vagotomy per se also increased IVR and absorption rate and decreased PD. In vagotomized animals, decreases in CBV had no consistent effects on IVR, net fluid absorption rate, or PD. The results are compatible with cardiac receptor modulation of both blood flow and fluid absorption rate in the feline jejunum. Differences in the response patterns for the vascular and absorptive effects suggest that they may be mediated by separate efferent pathways.

The behavioural approach in medical practice

This paper gives a description of the behavioural approach, behaviour therapy, and behavioural medicine in a medical and general hospital setting and describes the intimate link between behaviour and illness, showing how knowledge of the way learning takes place and influences behaviour can lead to a better understanding of the aetiology of illness and thus to appropriate treatment. A behavioural approach can be applied to the understanding and treatment of medical problems associated with sphincteric disturbances, such as childhood encopresis and urinary retention, as well as to the improvement of patient compliance and to the better management of pain. In the field of preventive medicine this approach is of importance in modifying behaviour associated with cardiovascular disorders, obesity, and smoking.

Carotid sinus baroreceptor modulation of fluid transport and blood flow in the feline jejunum

Carotid sinus baroreceptor control of jejunal fluid transport and vascular resistance was studied in chloralose-anesthetized cats. The carotid sinuses were isolated and perfused with blood from the femoral arteries. The aortic nerves were divided. In an isolated jejunal segment we measured net fluid transport rate, transmural potential difference (PD), and blood flow at a constant perfusion pressure of 75 mmHg. Carotid sinus pressure (CSP) was increased to 200-250 mmHg and was then lowered, in steps of approximately 25 mmHg, down to 50 mmHg. In the pressure interval from 90 to 200 mmHg, decreases in CSP increased jejunal vascular resistance and fluid absorption rate and decreased PD. In the interval from 50 to 90 mmHg, decreases in CSP increased vascular resistance and decreased PD but did not affect net fluid absorption rate. The results indicate that changes in baroreceptor activity may reflexly influence both vascular resistance and fluid transport rate in the feline jejunum, possibly via separate sympathetic mechanisms.

Strategies for living: teaching psychological self-help as adult education

This paper briefly describes some of the traditional approaches to teaching psychological skills and self-help techniques to non-psychologists. It is stressed that there have been few attempts to teach individuals a broad range of self-help strategies for dealing with psychological problems. The paper goes on to give a detailed description of a 12-week course of adult education evening classes designed for this purpose. During the course participants were taught strategies to improve self-awareness and relationships, to control anxiety, confront fears, reduce worrying thoughts, fight depression and cope with major life changes. In the main it appeared that students were able to assimilate and benefit from the techniques offered. It was concluded that adult education classes are an appropriate way of teaching psychological self-help, and provide a relevant alternative to more traditional treatment approaches.

Existential-behaviour therapy: a possible paradigm?

A comparative discussion is presented of existential and behavioural psychotherapy, indicating where behavioural theory, empirical research and single case studies can be related to the existential emphasis on phenomenology and personal confrontation with death, freedom, isolation and meaninglessness. The conclusions are that: more recent emphasis on cognitive variables in behaviour therapy has brought the two conceptual systems closer together; and there is improvement in the understanding of aetiology and clinical effectiveness when the therapist incorporates existential-behavioural constructs and methods of working.

Habitual rumination: a benign disorder

Nine patients who habitually ruminated after meals underwent clinical tests and psychological questioning. Barium meal radiography showed no abnormalities. In one patient oesophageal manometry detected an abnormally large gastric pressure wave 20 minutes after food. Although four patients had family psychiatric histories and three histories of overdose, anorexia nervosa, and mild reactive depression, none had any present serious psychiatric disorder. Behavioural therapy to reduce rumination was successful in one patient. Most patients responded to reassurance that the habit was harmless. Since the condition is a distinct clinical syndrome it may be recognised early with minimal investigations if doctors are aware of its existence.

The treatment of childhood-rooted separation anxiety in an adult

This paper describes the behavioral treatment of a continuing separation anxiety experienced by a 31 yr old male with a long history of school phobia in childhood. The patient was successfully treated by using a wide variety of behavioral strategies. One novel therapeutic technique was used: the patient wore a bleeper which sounded as a regular reminder to prepare for a phobic situation and to relax in the face of anticipated fearful events.