Frequency-dependent effects of background noise on subcortical response timing

The addition of background noise to an auditory signal delays brainstem response timing. This effect has been extensively documented using manual peak selection. Peak picking, however, is impractical for large-scale studies of spectrotemporally complex stimuli, and leaves open the question of whether noise-induced delays are frequency-dependent or occur across the frequency spectrum. Here we use an automated, objective method to examine phase shifts between auditory brainstem responses to a speech sound (/da/) presented with and without background noise. We predicted that shifts in neural response timing would also be reflected in frequency-specific phase shifts. Our results indicate that the addition of background noise causes phase shifts across the subcortical response spectrum (70-1000 Hz). However, this noise-induced delay is not uniform such that some frequency bands show greater shifts than others: low-frequency phase shifts (300-500 Hz) are largest during the response to the consonant-vowel formant transition (/d/), while high-frequency shifts (720-1000 Hz) predominate during the response to the steady-state vowel (/a/). Most importantly, phase shifts occurring in specific frequency bands correlate strongly with shifts in the latencies of the predominant peaks in the auditory brainstem response, while phase shifts in other frequency bands do not. This finding confirms the validity of phase shift detection as an objective measure of timing differences and reveals that this method detects noise-induced shifts in timing that may not be captured by traditional peak latency measurements.

A pilot study of a Mediterranean-type diet intervention in female patients with rheumatoid arthritis living in areas of social deprivation in Glasgow

BACKGROUND

A Mediterranean-type diet rich in fish, fruit and vegetables and low in saturated fats has been associated with health benefits, including improved cardiovascular profile and benefit in RA.

OBJECTIVE

To overcome obstacles to healthy eating by a community-based intervention promoting a Mediterranean-type diet in patients with RA living in socially deprived areas of Glasgow.

METHODS

130 female patients with RA aged 30-70 years (median 55), disease duration 8 years were recruited from three hospital sites. The intervention group (n = 75) attended weekly 2-hour sessions for 6 weeks in the local community, including hands-on cooking classes backed up with written information. The control group (n = 55) were given dietary written information only. Both groups completed food frequency questionnaires (FFQs), and clinical and laboratory measures were assessed at baseline, 3 and 6 months.

RESULTS

Significant benefit was shown in the intervention group compared with controls for patient global assessment at 6 months (p = 0.002), pain score at 3 and 6 months (p = 0.011 and 0.049), early morning stiffness at 6 months (p = 0.041) and Health Assessment Questionnaire score at 3 months (p = 0.03). Analysis of the FFQs showed significant increases in weekly total fruit, vegetable and legume consumption and improvement in the ratio of monounsaturated:saturated fat intake and systolic BP in the intervention group only. The cooking classes were positively received by patients and tutors; cost/patient for the 6 week course was 84 pounds (124 euro).

CONCLUSIONS

Results demonstrate that a 6 week intervention can improve consumption of healthier foods. If implemented more widely it may prove a popular, inexpensive and useful adjunct to other RA treatment.

Congenital diaphragmatic hernia: developing a protocolized approach

BACKGROUND/PURPOSE

The purpose of this study was to evaluate the evolving outcome of newborns who have congenital diaphragmatic hernia (CDH) using a protocolized approach to management, which includes extracorporeal membrane oxygenation (ECMO) and to present the details of such a management protocol.

METHODS

A retrospective chart review was conducted of the neonatal outcome of near-term (>34 weeks' gestation) newborns with CDH all referred to the Royal Alexandra Hospital either before or after delivery. A protocol was developed that included antenatal assessment, the use of antenatal steroids, planned delivery, use of prophylactic surfactant, pressure limited gentle ventilation, permissive hypercarbia and hypoxia, and venovenous ECMO, if indicated.

RESULTS

Sixty-five infants with CDH were treated from February 1989 through August 1996. Twenty-three infants were inborn, 20 of whom were antenatal referrals. Overall, 51 of the 65 infants survived (78%). Thirteen of the 23 inborn infants survived with conservative management, and 10 required ECMO, of whom, eight were long-term survivors. Thirty-eight infants required ECMO, and 26 survived (68%), whereas there were only two deaths among the 27 conservatively treated infants. Eighteen of 20 inborn infants with an antenatal diagnosis survived, compared with 13 of 21 (62%) outborn infants. An antenatal diagnosis before 25 weeks' gestation was associated with a 60% survival rate. Sixty-three percent of infants whose best postductal PaO2 value before ECMO was less than 100 torr survived, and 7 of 11 infants with a best postductal PaO2 value of less than 50 torr before ECMO survived (64%). The average age at surgery progressively increased over time both for infants who did not require ECMO (1.3 days to 5.8 days; P = .01) and for infants who received ECMO (1.9 days to 8.2 days; P = .016).

CONCLUSIONS

The use of a protocolized management for infants with CDH has been associated with improving outcome in a population at high risk. The components (either separately or combined) of these protocolized approaches need to be tested in prospective trials to determine their true benefit. In addition, there is a need to evaluate prospectively the outcomes of infants with CDH born in ECMO centers compared with those infants born in other tertiary care neonatal units to determine the most appropriate management of the fetus with CDH.

Differential binding of fibroblast growth factor-2 and -7 to basement membrane heparan sulfate: comparison of normal and abnormal human tissues

Fibroblast growth factors (FGFs) play multiple roles during development and in adult tissues as paracrine regulators of growth and differentiation. FGFs signal through transmembrane receptor tyrosine kinases, but heparan sulfate is also required for signaling by members of the FGF family. In addition, heparan sulfate may be involved in determining tissue distribution of FGFs. Using biotinylated FGF-2 and FGF-7 (KGF) as probes, we have identified specific interactions between FGFs and heparan sulfates in human tissues. Both FGF species bind to tissue mast cells and to epithelial cell membranes. Binding to basement membrane heparan sulfate is tissue source dependent and specific. Although FGF-2 strongly binds to basement membrane heparan sulfate in skin and most other tissue sites examined, FGF-7 fails to bind to basement membrane heparan sulfate in most locations. However, in subendothelial matrix in blood vessels and in the basement membrane of a papillary renal cell carcinoma, strong FGF-7 binding is seen. In summary, distinct and specific affinities of heparan sulfates for different FGFs were identified that may affect growth factor activation and local distribution. Heparan sulfate may have a gatekeeper function to either restrict or permit diffusion of heparin-binding growth factors across the basement membrane.

How nursing research makes a difference

"Better Health Through Nursing Research" is the theme of International Nurses' Day (IND) 1996. The following examples demonstrate that a large body of evidence exists that shows that nursing care has significant effects upon health outcomes and costs of care. While much more work remains to be done, particularly with the link of research to practice and research to policy, nurse scientists are very active in making significant contributions to the quality of peoples' lives.

Timing of repair of congenital diaphragmatic hernia requiring extracorporeal membrane oxygenation support

Treatment of congenital diaphragmatic hernia (CDH) has undergone a revolutionary change in philosophy, from previous urgent repair to the present practice of stabilization and delayed repair. However, when extracorporeal membrane oxygenation (ECMO) is required, many people believe that the risk of postoperative pulmonary hypertension (PPHN) mandates hernia repair while on ECMO. This report details the experience in two ECMO centers with stabilization, ECMO if required, and CDH repair post-ECMO. All CDH patients symptomatic in the first hour of life with a gestational age of at least 34 weeks during the period were reviewed retrospectively. Standard criteria were used to select patients for ECMO. High-frequency jet or oscillating ventilators and nitric oxide were not routinely available throughout the study period, but were used in some of the more recent patients. A total of 60 patients presented to the two centers; 24 cases were stabilized with conventional management, repair of the CDH was done elective, and survival was 100%. Eight patients were referred after having repair elsewhere; six survived (75%). The two deaths were attributable to associated lethal lesions--complex cyanotic heart disease and alveolar capillary dysplasia. Eight patients who required ECMO were managed with the intention of repairing the defect on ECMO. Four survived (50%). Two patients died before repair. Twenty patients were managed with ECMO, with the intention of repairing the defect after decannulation. Overall survival was 13 (65%), deaths were caused by pre-ECMO hypoxia, pulmonary insufficiency, and associated cardiac disease. No patient had recurrent pulmonary hypertension after late repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Fetal response to carbon dioxide pneumoperitoneum in the pregnant ewe

OBJECTIVE

To determine the effects of maternal abdominal carbon dioxide (CO2) insufflation on placental blood flow and fetal blood gas measurements in the pregnant ewe.

METHOD

Five time-bred ewes at 110 days' gestation were surgically prepared with maternal and fetal catheters placed for subsequent measurement of vascular pressures, blood gas tensions, and placental blood flows. On surgical recovery day 3, the ewe was anesthetized, placed on her right side, intubated, and manually ventilated to maintain a constant maternal carbon dioxide pressure (PCO2) range (37.1 +/- 3.3 mmHg) for the duration of the experiment. The maternal abdomen was inflated with CO2 to maintain an intraabdominal pressure of 20.7 +/- 0.6 mmHg. Maternal and fetal blood flows and blood gases were determined at 30 minutes of ventilation, 60 minutes of insufflation, and 40 minutes of desufflation. Simultaneous maternal and fetal organ blood flows were determined using the radioactive microsphere technique.

RESULTS

Maternal perfusion pressure fell 22% (P = .01) in response to insufflation, whereas pressure in the inferior vena cava rose 53% (P = .003). Maternal placental blood flow fell to 61% (P = .002) of control. Seventy-seven percent of this blood-flow change was in response to the decreased perfusion pressure, with 23% resulting from an increased placental vascular resistance of 32% (P = .02). Maternal blood gas values did not change with insufflation or desufflation. Despite the marked decrease in maternal placental blood flow, the fetal placental perfusion pressure and blood flow, pH, and blood gas tensions were unaffected by insufflation or desufflation.

CONCLUSION

The sheep fetus has sufficient placental flow reserves or compensatory responses to maintain adequate gas exchange during a 1-hour, 20 mmHg maternal pneumoperitoneum. Laparoscopic surgical procedures may prove to be a safe alternative to laparotomy during pregnancy.

Older patients' experiences of discharge from hospital

The second paper in a series describes the work of the Nursing Research Unit at the University of Edinburgh studying discharge planning for older patients going home from acute hospital care is described. Data were collected on the views and experiences of 326 patients aged 75 years and over and 117 of their carers. Ward sisters also completed questionnaires about ward structures and processes relating to discharge planning. Problems typical of those reported in previous similar studies were found.

Community nurses & discharge planning

The role of community nurses in discharge planning for elderly patients leaving hospital is of increasing importance in the wake of the NHS and Community Care Act 1990. Community nurses can play a key role in contributing to pre-discharge assessments and in providing continuing post-discharge assessment and care. The Nursing Research Unit at the University of Edinburgh conducted a survey early in 1993, just prior to implementation of the Community Care Act in Scotland, to ascertain the views and experiences of a national 1 in 3 sample of community nurses relating to the discharge of elderly people from acute hospitals. This article presents the results of that survey and offers recommendations regarding the role of community nurses in discharge planning for elderly patients.

Expressed emotion, social skill, and response to negative affect in schizophrenia

The social skills and social perception of schizophrenia patients in response to negative affect was examined as a function of family expressed emotion (EE). Patients participated in a role-play test, a social perception test, and a problem-solving discussion with a family member and were assessed on several measures of symptomatology. EE of family members was evaluated with the Camberwell Family Interview. On the role-play test, patients with less critical relatives became more assertive in response to increased negative affect from a confederate portraying either a family member or friend, but patients with highly critical relatives did not. Patients with highly critical relatives were also less assertive when confronted with negative affect from a confederate portraying a family member rather than a friend. The behaviors of both relatives and patients during a family problem-solving interaction were related to the EE dimensions of criticism, emotional overinvolvement, and warmth. Patient gender was also related to family problem solving but was independent of EE. Patient ratings of affect on a videotaped social perception task were not related to family EE, and there were few differences in psychopathology between patients with high and low EE relatives. The results support the validity of the EE construct as an index of relatives' affective behavior and suggest that patients' social skills, such as assertiveness, may mediate negative affective exchanges in their families.

Purchasing palliative care: availability and cost implications

This paper reports on a survey of the availability of palliative care in Scotland, in the context of the internal market introduced as part of the NHS reforms. It is based on a survey of both the cost and availability of such service, with a discussion of the implications of this information for purchasers of palliative care.

Discharge planning for elderly patients

Discharge planning for older patients is gaining recognition as a process requiring improvement. Demographic changes have produced an increasing population of elderly patients in the acute hospital sector, many of whom need co-ordinated discharge planning and appropriate post-discharge support. This article discusses the accumulated research findings of the past 20 years, which have highlighted the need for health services research, policy and practice to improve the effectiveness of discharge planning for elderly people.

Expressed emotion, social skill, and response to negative affect in schizophrenia

The social skills and social perception of schizophrenia patients in response to negative affect was examined as a function of family expressed emotion (EE). Patients participated in a role-play test, a social perception test, and a problem-solving discussion with a family member and were assessed on several measures of symptomatology. EE of family members was evaluated with the Camberwell Family Interview. On the role-play test, patients with less critical relatives became more assertive in response to increased negative affect from a confederate portraying either a family member or friend, but patients with highly critical relatives did not. Patients with highly critical relatives were also less assertive when confronted with negative affect from a confederate portraying a family member rather than a friend. The behaviors of both relatives and patients during a family problem-solving interaction were related to the EE dimensions of criticism, emotional overinvolvement, and warmth. Patient gender was also related to family problem solving but was independent of EE. Patient ratings of affect on a videotaped social perception task were not related to family EE, and there were few differences in psychopathology between patients with high and low EE relatives. The results support the validity of the EE construct as an index of relatives' affective behavior and suggest that patients' social skills, such as assertiveness, may mediate negative affective exchanges in their families.

Neurological melioidosis: seven cases from the Northern Territory of Australia

Pseudomonas pseudomallei, which causes melioidosis, is most commonly associated with pulmonary infection. We describe seven patients who developed a neurological syndrome as the predominant manifestation of melioidosis: this syndrome was characterized by peripheral motor weakness (mimicking Guillain-Barré syndrome), brain-stem encephalitis, aseptic meningitis, and respiratory failure. Neurological melioidosis occurred in the absence of demonstrable foci of infection in the central nervous system (CNS) in five of six patients whose cerebrospinal fluid was available for culture. Computed tomography and magnetic resonance imaging of the brain and spinal cord of these patients were not suggestive of pyogenic infection, although the latter procedure detected brain-stem encephalitis. Autopsy findings in one case confirmed brain-stem encephalitis without evidence of direct bacterial infection. The clinical presentation of neurological melioidosis includes features of an exotoxin-induced neurological syndrome, with profound neurological disease occurring in the absence of apparent direct infection of the CNS. This syndrome appears to be a newly recognized clinical presentation of melioidosis.

Circulating interferon-alpha levels and hypertriglyceridemia in the acquired immunodeficiency syndrome

PURPOSE

The metabolic disturbances seen during infection are thought to be due to cytokines, modulators of the immune response. The acquired immunodeficiency syndrome (AIDS) is characterized by a high prevalence of hypertriglyceridemia and at times depletion of body cell mass (wasting). Elevated circulating levels of cytokines have also been reported in AIDS. Therefore, we determined the relationship between circulating cytokine levels and lipid levels and between circulating cytokine levels and wasting in AIDS and human immunodeficiency virus (HIV) infection.

PATIENTS AND METHODS

Serum samples from 45 patients with AIDS, 13 subjects with evidence of HIV infection by presence of antibody but without AIDS (HIV positive), and 17 seronegative control subjects who had previously undergone body composition analysis were analyzed for triglyceride, cholesterol, interferon, tumor necrosis factor (TNF), and interleukin-1 levels. Eleven subjects with AIDS or HIV infection had sequential measurements. Interferon was analyzed by bioassay with identification using specific antibodies. TNF and interleukin-1 were assayed by enzyme-linked immunosorbent assay. Lean body mass was assessed by total body potassium.

RESULTS

Serum interferon-alpha levels were significantly elevated in patients with AIDS (p less than 0.001 compared to controls), with detectable levels in 84% of AIDS patients. Interferon-alpha was not detectable in serum from controls, while three of 13 HIV-positive subjects had detectable interferon-alpha levels. There was a significant correlation between interferon-alpha levels and serum triglyceride levels in AIDS and HIV-positive patients (R = 0.446, p less than 0.002). There was no relationship between interferon-alpha and serum cholesterol levels (R = -0.039, NS). In contrast only 11% of AIDS patients had detectable circulating TNF levels; the mean value for and the prevalence of detectable serum TNF levels were not significantly different from those of control subjects. Interleukin-1 was not detected in the circulation. There was no correlation between the presence of circulating TNF and serum triglycerides. There was no relationship between circulating interferon-alpha or TNF levels and the presence of wasting as measured by total body potassium.

CONCLUSION

These studies suggest that interferon-alpha, which has previously been shown to modulate lipid metabolism in vivo and in vitro, may be responsible for the hypertriglyceridemia found in AIDS.

Remediation of cognitive deficits in schizophrenia

Studies have suggested that schizophrenia is characterized by an impairment in the dorsolateral prefrontal cortex that prevents learning of some elementary information processing tasks. To test this hypothesis, the authors administered the Wisconsin Card Sorting Test to 16 schizophrenic inpatients with standard instructions and either contingent or noncontingent reinforcement. Performance was markedly impaired under each condition. A second cohort (N = 12) was tested after receiving instructions plus rehearsal and feedback. These subjects' performance was comparable to nonpatient norms and was maintained on a subsequent day. The results indicate that deficits in performance on the Wisconsin Card Sorting Test are remediable, whether or not they are due to neurological impairment.

HIV infection and community nursing staff in Scotland--2. Knowledge and attitudes

Findings from a survey of community nursing staff in Scotland reveal that there is limited knowledge about many aspects of HIV infection. Respondents were concerned about their lack of experience and knowledge as well as the in-service education that they had received. A substantial minority of community nursing staff felt that they should have the right to refuse to care for HIV-infected patients and those whose lifestyle put them at risk of HIV infection. A majority of staff felt that health professionals who are most at risk of contact with HIV-infected materials should be informed of patients' HIV-antibody status without their consent. There were also some indications of a lack of confidence in service managers and recommendations are made regarding ways of increasing both the knowledge and confidence of front-line staff.

Detection of HIV-1 RNA in the lamina propria of patients with AIDS and gastrointestinal disease

Thirty formaldehyde-fixed, paraffin-embedded endoscopic biopsy specimens from the colon and rectum of 25 patients with acquired immunodeficiency syndrome were examined using a [35S]HIV-RNA in situ hybridization procedure. Nine of the specimens contained cells that bound significant amounts of probe. Cells were considered positive if more than 50 grains of silver (over background) per 200 micron 2 were seen over cells that did not stain with eosin. Most of the positive cells resembled macrophages, although cells with condensed nuclei resembling lymphocytes were found. No epithelial cells expressing viral RNA were detected. Formaldehyde-fixed eosinophils gave spurious signals that could be reduced with sulfhydryl modifying agents. HIV-1 may be disseminated in the lamina propria of the gut at low concentrations in some patients but may not be detectable in others. The lower gut lining may be both a portal of initial infection with HIV and a target of disseminated HIV infection.