A protein-free chemically defined medium for the cultivation of various micro-organisms with food safety significance

AIMS

To develop a broadly applicable medium free of proteins with well-defined and reproducible chemical composition for the cultivation of various micro-organisms with food safety significance.

METHODS AND RESULTS

The defined medium was designed as a buffered minimal salt medium supplemented with amino acids, vitamins, trace metals and other nutrients. Various strains commonly used for food safety research were selected to test the new defined medium. We investigated single growth factors needed by different strains and the growth performance of each strain cultivated in the defined medium. Results showed that the tested strains initially grew slower in the defined medium compared to tryptic soy broth, but after an overnight incubation cultures from the defined medium reached adequately high cell densities.

CONCLUSIONS

The newly designed defined medium can be widely applied in food safety studies that require media with well-defined chemical constituents.

SIGNIFICANCE AND IMPACT OF THE STUDY

Defined media are important in studies of microbial metabolites and physiological properties. A defined medium capable of cultivating different strains simultaneously is needed in the food safety area. The new defined medium has broader applications in comparing different strains directly and provides more reproducible results.

Acetonitrile based single step slot-die compatible perovskite ink for flexible photovoltaics

Low viscosity rapid drying perovskite formulations designed to give high quality solar films when slot-die coated on flexible roll-to-roll compatible substrates are developed .

Crowd medical services in the English Football League: remodelling the team for the 21st century using a realist approach

OBJECTIVES

To evaluate the new model of providing care based on demand. This included reconfiguration of the workforce to manage workforce supply challenges and meet demand without compromising the quality of care.

DESIGN

Currently the Sports Ground Safety Authority recommends the provision of crowd medical cover at English Football League stadia. The guidance on provision of services has focused on extreme circumstances such as the Hillsborough disaster in 1989, while the majority of demand on present-day services is from patients with minor injuries, exacerbations of injuries and pre-existing conditions. A new model of care was introduced in the 2009/2010 season to better meet demand. A realist approach was taken. Data on each episode of care were collected over 14 consecutive football league seasons at Millwall FC divided into two periods, preimplementation of changes and postimplementation of changes. Data on workforce retention and volunteer satisfaction were also collected.

SETTING

The data were obtained from one professional football league team (Millwall FC) located in London, UK.

PRIMARY AND SECONDARY OUTCOMES

The primary outcome was to examine the demand for crowd medical services. The secondary outcome was to remodel the service to meet these demands.

RESULTS

In total, 981 episodes of care were recorded over the evaluation period of 14 years. The groups presenting, demographic and type of presentation did not change over the evaluation. First aiders were involved in 87.7% of episodes of care, nurses in 44.4% and doctors 17.8%. There was a downward trend in referrals to hospital. Workforce feedback was positive.

CONCLUSIONS

The new workforce model has met increased service demands while reducing the number of referrals to acute care. It involves the first aid workforce in more complex care and key decision-making and provides a flexible registered healthcare professional team to optimise the skill mix of the team.

A transparent conductive adhesive laminate electrode for high-efficiency organic-inorganic lead halide perovskite solar cells

A self-adhesive laminate solar-cell electrode is presented based on a metal grid embedded in a polymer film (x-y conduction) and set in contact with the active layer using a pressure-sensitive adhesive containing a very low quantity (1.8%) of organic conductor, which self-organizes to provide z conduction to the grid. This ITO-free material performs in an identical fashion to evaporated gold in high-efficiency perovskite solar cells.

Organic geochemical studies of modern microbial mats from Shark Bay: Part I: Influence of depth and salinity on lipid biomarkers and their isotopic signatures

The present study investigated the influence of abiotic conditions on microbial mat communities from Shark Bay, a World Heritage area well known for a diverse range of extant mats presenting structural similarities with ancient stromatolites. The distributions and stable carbon isotopic values of lipid biomarkers [aliphatic hydrocarbons and polar lipid fatty acids (PLFAs)] and bulk carbon and nitrogen isotope values of biomass were analysed in four different types of mats along a tidal flat gradient to characterize the microbial communities and systematically investigate the relationship of the above parameters with water depth. Cyanobacteria were dominant in all mats, as demonstrated by the presence of diagnostic hydrocarbons (e.g. n-C17 and n-C17:1). Several subtle but important differences in lipid composition across the littoral gradient were, however, evident. For instance, the shallower mats contained a higher diatom contribution, concordant with previous mat studies from other locations (e.g. Antarctica). Conversely, the organic matter (OM) of the deeper mats showed evidence for a higher seagrass contribution [high C/N, 13C-depleted long-chain n-alkanes]. The morphological structure of the mats may have influenced CO2 diffusion leading to more 13C-enriched lipids in the shallow mats. Alternatively, changes in CO2 fixation pathways, such as increase in the acetyl COA-pathway by sulphate-reducing bacteria, could have also caused the observed shifts in δ13C values of the mats. In addition, three smooth mats from different Shark Bay sites were analysed to investigate potential functional relationship of the microbial communities with differing salinity levels. The C25:1 HBI was identified in the high salinity mat only and a lower abundance of PLFAs associated with diatoms was observed in the less saline mats, suggesting a higher abundance of diatoms at the most saline site. Furthermore, it appeared that the most and least saline mats were dominated by autotrophic biomass using different CO2 fixation pathways.

Prevention and intervention programs for juvenile offenders

Over the past decade researchers have identified intervention strategies and program models that reduce delinquency and promote pro-social development. Preventing delinquency, says Peter Greenwood, not only saves young lives from being wasted, but also prevents the onset of adult criminal careers and thus reduces the burden of crime on its victims and on society. It costs states billions of dollars a year to arrest, prosecute, incarcerate, and treat juvenile offenders. Investing in successful delinquency-prevention programs can save taxpayers seven to ten dollars for every dollar invested, primarily in the form of reduced spending on prisons. According to Greenwood, researchers have identified a dozen "proven" delinquency-prevention programs. Another twenty to thirty "promising" programs are still being tested. In his article, Greenwood reviews the methods used to identify the best programs, explains how program success is measured, provides an overview of programs that work, and offers guidance on how jurisdictions can shift toward more evidence-based practices The most successful programs are those that prevent youth from engaging in delinquent behaviors in the first place. Greenwood specifically cites home-visiting programs that target pregnant teens and their at-risk infants and preschool education for at-risk children that includes home visits or work with parents. Successful school-based programs can prevent drug use, delinquency, anti-social behavior, and early school drop-out. Greenwood also discusses community-based programs that can divert first-time offenders from further encounters with the justice system. The most successful community programs emphasize family interactions and provide skills to the adults who supervise and train the child. Progress in implementing effective programs, says Greenwood, is slow. Although more than ten years of solid evidence is now available on evidence-based programs, only about 5 percent of youth who should be eligible participate in these programs. A few states such as Florida, Pennsylvania, and Washington have begun implementing evidence-based programs. The challenge is to push these reforms into the mainstream of juvenile justice.

The performance of Pipelle endometrial sampling in a dedicated postmenopausal bleeding clinic

Endometrial sampling using the Pipelle device is widely used in the UK especially in the investigation of postmenopausal bleeding. This study was aimed at evaluating the clinical benefit and diagnostic accuracy of the procedure in the setting of a dedicated one-stop clinic for women with postmenopausal bleeding. The study also examined the factors that would affect the adequacy of endometrial samples in terms of their suitability for histopathalogical examination. Data from 97 consecutive patients attending the clinic were collected and analysed. All the patients had a transvaginal ultrasound scan and an endometrial Pipelle sample was attempted unless refused by the patient. The analysis revealed that the procedure avoided the need for hysteroscopy in 61.5% of cases with an endometrial thickness of > 4mm. No cases of endometrial cancer were missed after successful Pipelle sampling. The ability to obtain an adequate endometrial sample was primarily affected by the endometrial thickness. There is only a 27% probability of getting an adequate endometrial sample in the group of women with an endometrial thickness of < 5 mm. The study recommends this procedure for the group of women with an endometrial thickness of > 4 mm. However, when the endometrial thickness is < or = 4 mm, little can be gained from endometrial sampling as malignancy is rare and the chance of getting an adequate sample is small.

Aggregation of nanosized colloidal silica in the presence of various alkali cations investigated by the electrospray technique

The slow aggregation process of a concentrated silica dispersion (Bindzil 40/220) in the presence of alkali chlorides (LiCl, NaCl, KCl, RbCl, and CsCl) was investigated by means of mobility measurements. At intervals during the aggregation, particles and aggregates were transferred from the liquid phase to the gas phase via electrospray (ES) and subsequently size selected and counted using a scanning mobility particle sizer (SMPS). This method enables the acquisition of particle and aggregate size distributions with a time resolution of minutes. To our knowledge, this is the first time that the method has been applied to study the process of colloidal aggregation. The obtained results indicate that, independent of the type of counterion, a sufficient dilution of the formed gel will cause the particles to redisperse. Hence, the silica particles are, at least initially, reversibly aggregated. The reversibility of the aggregation indicates additional non-DLVO repulsive steric interactions that are likely due to the presence of a gel layer at the surface. The size of the disintegrating aggregates was monitored as a function of the time after dilution. It was found that the most stable aggregates were formed by the ions that adsorb most strongly on the particle surface. This attractive effect was ascribed to an ion-ion correlation interaction.

An analysis of use of crowd medical services at an English football league club

AIM

Although crowd medical services in English league football are common, there is little data examining the use of such services. The aim of this study was to provide detailed data by examining the usage of the Crowd Medical Service at a First Division Football Club (Millwall FC) over six Football League seasons. This usage has implications in terms of resources, provision of level of service and training needs of staff.

METHODS

A prospective data collection form was designed and used to capture all episodes of care over the length of six football league seasons, each approximately 9 months in duration which resulted in a census of activity. This included episodes that did not normally require detailed documentation for statutory purposes, such as informal advice.

RESULTS

There were 445 episodes of care recorded over 146 home games. Over six years presentation was consistent. This gives a mean of 3.14 episodes per game (2.7-4.1). There is little research in this area and so it is difficult to compare uptake with other clubs. The episodes of care were broadly grouped into medical (67.0%) or injury (33.0%). Most of those presenting did so with non-emergent (pre-existing) medical problems or minor injuries. Staff (for example Stewards) made up 44% of consultations. One hundred and eight people had a primary and secondary reason for presenting. Such episodes are more time consuming and in turn have an impact on resources. Some stated they had presented because of ease of access to the service, they found access to their General Practitioner (GP) difficult or were not registered with a GP at all.

CONCLUSION

The principal focus of a crowd medical service is to manage a major incident and medically emergent spectators. The majority of presentations were minor injuries and pre-existing medical conditions. In addition staff make up a significant proportion of the users. Some re-focussing of guidance is therefore necessary if these results are typical of English League Football. In turn this reflects a need for more education in the management of minor injuries and chronic disease management and recognition in training and service provision.

Effect of membrane character and solution chemistry on microfiltration performance

To help understand and predict the role of natural organic matter (NOM) in the fouling of low-pressure membranes, experiments were carried out with an apparatus that incorporates automatic backwashing and long filtration runs. Three hollow fibre membranes of varying character were included in the study, and the filtration of two different surface waters was compared. The hydrophilic membrane had greater flux recovery after backwashing than the hydrophobic membranes, but the efficiency of backwashing decreased at extended filtration times. NOM concentration of these waters (7.9 and 9.1mg/L) had little effect on the flux of the membranes at extended filtration times, as backwashing of the membrane restored the flux to similar values regardless of the NOM concentration. The solution pH also had little effect at extended filtration times. The backwashing efficiency of the hydrophilic membrane was dramatically different for the two waters, and the presence of colloid NOM alone could not explain these differences. It is proposed that colloidal NOM forms a filter cake on the surface of the membranes and that small molecular weight organics that have an adsorption peak at 220nm but not 254nm were responsible for "gluing" the colloids to the membrane surface. Alum coagulation improved membrane performance in all instances, and this was suggested to be because coagulation reduced the concentration of "glue" that holds the organic colloids to the membrane surface.

Clinico-epidemiological profile and validation of symptoms and signs of severe illness in young infants (< 60 days) reporting to a district hospital

OBJECTIVES

To describe the clinical and epidemiological profile of infants less than 2 months of age reporting to a district hospital and to assess the ability of simple clinical symptoms and signs used by health workers to detect severe illness warranting hospital admission.

METHODS

It was an observational study done at a general district hospital at Chandigarh, North India. Infants less than 2 months of age presenting to this hospital were enrolled. All infants were first evaluated by an auxiliary nurse midwife (ANM) to record a pre-determined set of symptoms and signs. A pediatrician who was blinded to the findings of the ANM did an independent assessment for severe illness needing urgent hospitalization.

RESULTS

A total of 1268 infants were enrolled. Of these, 356 (28%) were below 7 days of age. Overall, regurgitation, vomiting and stool problems (25%) were the most common presenting complaints in the first 2 months of life, followed by jaundice (22%) and respiratory symptoms (15%). 112 (8.8%) infants were classified as having "severe illness requiring urgent hospital management" by the pediatrician. Nearly half (46%) of the admissions were because of jaundice while 17% each were due to sepsis and pneumonia / lower respiratory tract infection (LRTI). A history of not feeding well (OR 14.7, 8.0 and 11.3 in 0-6, 7-27 and 28-59 days age groups, respectively) and a respiratory rate >60/min (OR 21.5, 6.2 and 10.5 in 0-6, 7-27 and 28-59 days age groups, respectively) had significant positive predictive value to predict severe illness (except jaundice) in all the 3 age groups studied. In the second month of life, severe chest in-drawing (OR 4.6) was also a significant predictor.

CONCLUSIONS

Simple clinical signs are useful in hands of health worker for identifying neonates with serious illness warranting hospital admission. These will be of use in the further development of clinical algorithms for the national integrated management of childhood illnesses.

Clinicoepidemiological profile and predictors of severe illness in young infants (< 60 days) reporting to a hospital in North India

OBJECTIVES

To describe the clinical and epidemiological profile of young infants reporting to a hospital and assess previously proposed simple clinical signs for their value in enabling health workers to detect young infants with severe illness warranting hospital admission.

METHODS

Observational study of infants less than 2 months of age presenting consecutively to a large public hospital in South Delhi who were evaluated by a health worker (nurse), on a standardized list of signs and symptoms, and the ability of these were evaluated against the need for hospital admission which was assessed by an independent pediatrician.

RESULTS

Of the 1624 young infants triaged, 878 were enrolled into the study. Of these 100 (11%) were below 7 days of age, for whom the common reasons for seeking care were jaundice (52%), not feeding well (6%) and fever (5%). The remaining 778 (89%) were 7-59 days of age with respiratory symptoms as the main presenting complaints (29.1%). The primary clinical diagnoses in infants with serious illness needing admission to hospital in the age group <7 days (n = 66) were hyperbilirubinemia (56%) and sepsis (21%). In those between 7-27 days of age (n = 60), primary diagnoses were sepsis (27%), pneumonia (13%), diarrhea, dysentery or dehydration (10%), while in the age group 28-59 days of age (n = 47) pneumonia (40%), sepsis (19%) and diarrhea or dehydration (13%) were the common primary diagnoses. Signs that had at least a prevalence of 5% and were strong predictors for all the age categories studied were history of difficult feeding (OR 6.8 for 0-6 days, 15.1 for 2-27 days and 6.2 for 28-59 days age groups), not feeding well on observation (OR 13.7, 27.6 and 20.9 respectively for the 3 age groups), temperature > 37.5C (OR 21.8, 14.6 and 30.0 respectively for the 3 age groups) and respiratory rate > 60 per minute (OR 6.8, 15.1 and 21.0 respectively for the 3 age groups). Additional strong predictors with > 5% prevalence were history of convulsions (OR 7.9, only in 0-6 day age group), lethargy (OR 26.1, only in 7-27 day age group), and history of diarrhea (OR 3.0 for 2-27 days and 2.2 for 28-59 days age groups).

CONCLUSIONS

Simple clinical signs are useful in hands of health worker for identifying neonates with serious illness warranting hospital admission. These will be of use in the further development of clinical algorithms for the national integrated management of childhood illnesses.

Chest X-ray-confirmed pneumonia in children in Fiji

OBJECTIVE

To calculate the incidence and document the clinical features of chest X-ray- (CXR-) confirmed pneumonia in children aged between 1 month and 5 years living in Greater Suva, Fiji.

METHODS

A retrospective review was undertaken of children aged between 1 month and 5 years with a discharge diagnosis suggesting a lower respiratory tract infection (LRTI) admitted to the Colonial War Memorial Hospital in Suva, Fiji, in the first 10 days of each month from 1 January 2001 to 31 December 2002. Clinical data were collected and CXRs were reread and classified according to WHO standardized criteria for CXR-confirmed pneumonia.

FINDINGS

Two hundred and forty-eight children with LRTI met the inclusion criteria. CXRs were obtained for 174 (70%) of these cases, of which 59 (34%) had CXR-confirmed pneumonia. The annual incidence of CXR-confirmed pneumonia was 428 cases per 100,000 children aged between 1 month and 5 years living in Greater Suva. If a similar proportion of the children for whom CXRs were unavailable were assumed to have CXR-confirmed pneumonia, the incidence was 607 per 100,000. The incidence appeared to be higher in Melanesian Fijian than Indo-Fijian children. The case-fatality rate was 2.8% in all children with LRTI, and 6.8% in those with CXR-confirmed pneumonia.

CONCLUSION

This is the first study to document the incidence of CXR-confirmed pneumonia in a Pacific Island country, and demonstrates a high incidence. A significant proportion of hospital admissions of children with LRTI are likely to be preventable by the introduction of pneumococcal conjugate vaccine.

Inevitable risk of high-order multiple pregnancies following IUI, the need for strict criteria for its prevention: two case reports

Intrauterine insemination with controlled super-ovulation (IUI/SO) is appropriate management of subfertility where the Fallopian tubes are healthy and patent and the sperm quality is satisfactory. The treatment is monitored by intermittent transvaginal ultrasound scans to assess follicular development. There is an unavoidable increased risk of multiple pregnancy including higher order pregnancy. These two case reports suggest the need for national standards regarding the abandonment of the treatment cycle to further reduce the risk of high order multiple implantations.

A decade of drug treatment court research

As drug treatment courts have multiplied over the past decade, so too have research evaluations conducted on their implementation and effectiveness. This article explores the decade of drug treatment court research conducted at RAND, starting with the experimental field evaluation of Maricopa's drug testing and treatment options to the most current 14-site national evaluation of courts funded in 1995-96 by the Drug Court Program Office. The article presents summaries of findings, a brief description of a drug treatment court typology, and suggestion of where future research might focus.

The analysis of forensic samples using laser micro-pyrolysis gas chromatography mass spectrometry

Laser micropyrolysis gas chromatography-mass spectrometry is used for the analysis of paint, photocopier toner, and synthetic fiber materials to test the forensic potential of this emerging technology. It uses a laser microprobe to selectively target very small parts of the materials for GC-MS analysis. Whereas the paint and the toner samples were amenable to direct laser pyrolysis, the synthetic fibers proved transparent to the 1064 nm laser radiation. The difficulty with the fibers demonstrates that a specific laser wavelength may not be appropriate for all types of materials. Nevertheless, the fibers were able to be indirectly pyrolyzed by impregnation in a strongly absorbing graphite matrix. A vast array of hydrocarbon pyrolysates was detected from the different materials studied. Unique product distributions were detected from each sample and in sufficient detail to facilitate individual molecular characterization (i.e., molecular fingerprinting). The integrity of the laser data were confirmed by comparison to data obtained from the same samples by the more conventional pyroprobe pyrolysis GC-MS method. The high spatial resolution and selectivity of the laser method may be advantageous for specific forensic applications, however, further work may be required to improve the reproducibility of the data.

Spinal-cord involvement in diabetic peripheral neuropathy

The pathogenesis of diabetic distal symmetrical polyneuropathy (DSP) is poorly understood but there is some evidence that the disease process might extend beyond peripheral nerves. We used magnetic-resonance imaging to measure spinal-cord cross-sectional area in diabetic patients with and without DSP and in healthy controls. There were significant differences in cord area between the groups at C4/5 and T3/4 (p=0.004 and p=0.033, respectively), with a smaller cord area in those with DSP compared with controls (p=0.001 and p=0.016 for C4/5 and T3/4, respectively). These results indicate that DSP is not simply a disease of the peripheral nerve and that there is substantial involvement of the spinal cord.

Directional-tip endotracheal tubes for blind nasotracheal intubation

OBJECTIVES

To compare initial success rates of blind nasotracheal intubation using directional-tip endotracheal tubes vs standard endotracheal tubes.

METHODS

A prospective trial comparing directional-tip and standard endotracheal tubes during initial attempts at blind nasotracheal intubation (BNTI) at a university hospital ED. Using an alternating schedule, the directional-tip or standard tube was used for the first attempt at BNT1. An attempt was defined as beginning when the tube was placed through the nose into the posterior pharynx and ending when the patient was intubated or the tube was removed from the nares. After the intubation, the physician graded the difficulty of the technique (i.e., easy/routine, intermediate, difficult, or unable to intubate nasally).

RESULTS

There were 49 patients entered over 5 months. Patient presentations for the intubations were trauma (45.8%), overdose (33.3%), respiratory/cardiac event (12.5%), seizure (2.1%), and other (6.3%). Intubation was successful on the first attempt in 18 of 21 patients (86%; 95% CI, 64% to 97%) for the directional-tip tube vs 16 of 28 patients (57%; 95% CI, 37% to 76%) for the standard tube (p = 0.03). The groups did not differ in age, sex, clinical presentation, or perceived difficulty of intubation. Only 1 patient could not be intubated nasally and was subsequently intubated orally.

CONCLUSION

The use of directional-tip tubes may improve the success rate of the first attempt at BNTI.

Dance screen programs and development of dance clinics

Dance movements can be stressful to the body, and the required extreme positions may place physiologic structures at risk for acute, subacute, or chronic injury. The authors designed a screening program, conducted by a team of physical therapists, orthopedists, and dance instructors, to evaluate dancers for musculoskeletal problems and to make recommendations that would improve movement compensation, strength, endurance, and mobility.

Antiphospholipid syndrome in pregnancy: a diagnostic dilemma

OBJECTIVE

To present a case of severe pre-eclampsia in which diagnosis of the antiphospholipid syndrome was made after delivery, and to discuss pointers to the diagnosis.

CLINICAL FEATURES

A 32-year-old woman in her second pregnancy presented at 32 weeks' gestation with severe pre-eclampsia. Her persisting severe postpartum illness was investigated. The presence of anticardiolipin antibodies and lupus anticoagulant led to the diagnosis of antiphospholipid syndrome.

INTERVENTION AND OUTCOME

Induction of labour was successful, with delivery of a healthy baby girl. The patient made a full recovery after treatment with corticosteroids and warfarin.

CONCLUSION

The antiphospholipid syndrome should be considered in cases of severe early pre-eclampsia.

Dichotic perception and memory following electroconvulsive treatment for depression

Verbal and visuospatial memory and dichotic listening performance were examined in 15 acutely depressed patients with no history of ECT, 17 depressed patients currently in remission, 15 remitted depressed patients who had received ECT six months or more in the past, and 20 normal controls. The neuropsychological functioning of an additional group of 10 acutely depressed patients was also studied before and two weeks after ECT. The results revealed some evidence of logical and autobiographical memory impairment two weeks following ECT, but no evidence that ECT impaired dichotic listening ability. Rather, a normalisation of hemispheric laterality was apparent on the dichotic listening task following ECT and the concomitant relief from depression. There was also no evidence of cognitive dysfunction on any task in individuals who were tested six months or more following their last ECT treatment.

Sustained-attention capacity in young and older adults

The sustained-attention capacity of young (21-29 years) and older (65-78 years) adults was examined using a high-event rate digit-discrimination vigilance task presented at three levels of stimulus degradation. Increased stimulus degradation led to a reduction in the hit rate and to a greater decline in hit rate over blocks (increased vigilance decrement). Sensitivity (d') declined over blocks only at the highest level of stimulus degradation. Older adults had a lower hit rate and showed greater vigilance decrement than young adults, particularly when stimuli were highly degraded. However, both age groups showed the same pattern of stability in sensitivity when stimulus degradation was moderate, and sensitivity decrement over time when stimulus degradation was high. The results suggest that the process of sustained allocation of capacity--as reflected in temporal changes in sensitivity--operates similarly in young and older adults.

Sustained-attention capacity in young and older adults

The sustained-attention capacity of young (21-29 years) and older (65-78 years) adults was examined using a high-event rate digit-discrimination vigilance task presented at three levels of stimulus degradation. Increased stimulus degradation led to a reduction in the hit rate and to a greater decline in hit rate over blocks (increased vigilance decrement). Sensitivity (d') declined over blocks only at the highest level of stimulus degradation. Older adults had a lower hit rate and showed greater vigilance decrement than young adults, particularly when stimuli were highly degraded. However, both age groups showed the same pattern of stability in sensitivity when stimulus degradation was moderate, and sensitivity decrement over time when stimulus degradation was high. The results suggest that the process of sustained allocation of capacity--as reflected in temporal changes in sensitivity--operates similarly in young and older adults.

Use of impedance cardiography in evaluating the exercise response of patients with left ventricular dysfunction

Invasive studies in patients with left ventricular dysfunction show that data at rest (e.g. ejection fraction-EF) are poor predictors of the changes in cardiac output (CO) which occur with exercise. This investigation was undertaken to determine whether impedance cardiography could be used in such patients to assess CO response to exercise. The method was compared with the direct Fick method. Over a range of COs between 4 and 18 min-1 there was no systematic error. Reproducibility for CO over one week was highly significant (r = 0.94; P less than 0.001). Impedance cardiography was incorporated into routine exercise testing on a bicycle ergometer for a group of 15 patients (mean age 53.2 +/- 3.0 yrs, SEM) who had sustained a major myocardial infarct 6 to 12 months previously, (EF 38.1 +/- 3.5%, SEM). CO was measured at the end of each 3-min stage. In eight patients (EF 40.0 +/- 3.4%, SEM) CO response was abnormal with either a decrease or a failure to increase with increasing workloads. Conventional end-points i.e. angina, attainment of 85% of predicted maximum heart rate, abnormal blood pressure response or excessive dyspnoea did not indicate consistently a need to terminate the test. It is suggested that impedance cardiography is a useful non-invasive method of evaluating patients with left ventricular dysfunction.

A platelet release defect induced by aspirin or penicillin G does not increase gastrointestinal blood loss in thrombocytopenic rabbits

Gastrointestinal blood loss was compared in groups of normal and thrombocytopenic animals treated with medications known to induce qualitative platelet dysfunction. Thrombocytopenia was induced in rabbits by the intraperitoneal injection of busulphan dissolved in polyethylene glycol (PEG) at a dose of 60 mg/kg. Control animals received PEG alone; each group subsequently received daily intravenous injections of penicillin G, aspirin, sodium salicylate or isotonic saline. Mean daily gastrointestinal blood loss was determined by monitoring the appearance of 51Cr radioactivity in the faeces following the administration of 51Cr-labelled erythrocytes prior to the administration of the test and control therapies. The administration of penicillin G was not associated with increased gastrointestinal blood loss in the thrombocytopenic animals as compared with the saline treated thrombocytopenic controls. Platelet aggregation studies confirmed the presence of a mild but significant defect in platelet aggregation. Aspirin produced a more pronounced defect in platelet aggregation but did not induce increased bleeding in the normal animals as compared with the controls, nor did it exacerbate the bleeding in thrombocytopenic animals. Sodium salicylate did not produce an aggregation defect and did not significantly modify gastrointestinal blood loss. It was concluded that drug-induced qualitative platelet dysfunction does not necessarily increase bleeding through intact vessels despite previous evidence of a significant effect on platelet plug formation as monitored by the bleeding time.

Development of factor VIII:C antibodies in dogs with hemophilia A (factor VIII:C deficiency)

Classic hemophilia A (factor VIII:C deficiency) was diagnosed in a miniature Schnauzer dog and a breeding program established. Inbreeding and crossbreeding produced 16 hemophilic animals. All were initially treated with canine cryoprecipitate, as required, for sporadic hemorrhagic events. Five animals developed potent antibodies to canine factor VIII:C. All were the offspring of obligate carriers, resulting from the mating of a hemophilic purebred miniature Schnauzer male to a normal female Brittany spaniel. The mean age at first treatment and factor VIII exposure at the time of inhibitor development was 10.3 wk and 286.3 U, respectively. The remaining hemophilic animals have not developed antibodies, despite receiving a mean factor VIII dosage of 1.5 X 10(3) U. This group includes animals derived from a mating between the same purebred miniature Schnauzer hemophilic male and a purebred miniature Schnauzer carrier female. In each case, the antibodies recognize both canine and human but not porcine VIII:C. They are non-precipitating IgG immunoglobulins. Following inhibitor development, infusion of canine cryoprecipitate was hemostatically ineffective and factor VIII:C recovery at 30 min was negligible. Infusion of a concentrate of porcine factor VIII resulted in a correction of the hemostatic defect and optimal factor VIII:C recovery. All animals receiving porcine factor VIII:C subsequently developed antibodies to this protein. The chance occurrence of this complication should facilitate further studies directed at elucidating the pathogenesis and management of hemophilia complicated by the development of antibodies to factor VIII:C.

Analysis of putative high-mobility-group (HMG) proteins in neuronal and glial nuclei from rabbit brain

Putative high-mobility-group (HMG) proteins 1, 2, and 17 were detected in neuronal and glial nuclei isolated from the cerebral hemisphere of rabbit brain. Although divergent chromatin structures are present in these two populations of brain nuclei (i.e., neuronal nuclei exhibit a short DNA repeat length), no differences were apparent in the electrophoretic mobilities of putative HMG proteins 1, 2, and 17 on SDS gels.

Dream report following commissurotomy

This paper addresses the question of right hemisphere involvement in the visual components of dreaming. The rationale derives from an observed relation between reports of visual agnosia accompanied by dream cessation and the literature on right hemisphere specialization for visuo-spatial processes. All night sleep EEGs were recorded from subjects with partial or complete section of the corpus callosum and anterior commissure. Upon entering a EEG-, EOG- and EMG-defined REM episode, the subjects were awakened and questioned about dream content. All subjects examined in this fashion were able to recount some visual dream content. This result fails to support any notion of selective right hemisphere visual dream mediation.

Oxygen consumption in children with congenital diseases of the heart

1. An open-circuit method for the measurement of oxygen consumption in children which is suitable for use during cardiac catheterization has been described.

2. Since it has been previously shown that there is no systematic error in this method, the accuracy of the method is described by the random error (i.e. reproducibility). The reproducibility of the method has been determined by the repeated measurement of oxygen consumption in children with congenital diseases of the heart under specified ‘standard’ conditions.

3. A simple method of predicting the oxygen consumption in these children was devised by subjecting the data to a multivariate regression analysis.

4. It is concluded that the accuracy of these predictions, although considerably better than that in the published literature, is not good enough to merit its use in the routine haemodynamic assessment.