Safety and efficacy of tenecteplase in patients with wake-up stroke assessed by non-contrast CT (TWIST): a multicentre, open-label, randomised controlled trial

BACKGROUND

Current evidence supports the use of intravenous thrombolysis with alteplase in patients with wake-up stroke selected with MRI or perfusion imaging and is recommended in clinical guidelines. However, access to advanced imaging techniques is often scarce. We aimed to determine whether thrombolytic treatment with intravenous tenecteplase given within 4·5 h of awakening improves functional outcome in patients with ischaemic wake-up stroke selected using non-contrast CT.

METHODS

TWIST was an investigator-initiated, multicentre, open-label, randomised controlled trial with blinded endpoint assessment, conducted at 77 hospitals in ten countries. We included patients aged 18 years or older with acute ischaemic stroke symptoms upon awakening, limb weakness, a National Institutes of Health Stroke Scale (NIHSS) score of 3 or higher or aphasia, a non-contrast CT examination of the head, and the ability to receive tenecteplase within 4·5 h of awakening. Patients were randomly assigned (1:1) to either a single intravenous bolus of tenecteplase 0·25 mg per kg of bodyweight (maximum 25 mg) or control (no thrombolysis) using a central, web-based, computer-generated randomisation schedule. Trained research personnel, who conducted telephone interviews at 90 days (follow-up), were masked to treatment allocation. Clinical assessments were performed on day 1 (at baseline) and day 7 of hospital admission (or at discharge, whichever occurred first). The primary outcome was functional outcome assessed by the modified Rankin Scale (mRS) at 90 days and analysed using ordinal logistic regression in the intention-to-treat population. This trial is registered with EudraCT (2014-000096-80), ClinicalTrials.gov (NCT03181360), and ISRCTN (10601890).

FINDINGS

From June 12, 2017, to Sept 30, 2021, 578 of the required 600 patients were enrolled (288 randomly assigned to the tenecteplase group and 290 to the control group [intention-to-treat population]). The median age of participants was 73·7 years (IQR 65·9-81·1). 332 (57%) of 578 participants were male and 246 (43%) were female. Treatment with tenecteplase was not associated with better functional outcome, according to mRS score at 90 days (adjusted OR 1·18, 95% CI 0·88-1·58; p=0·27). Mortality at 90 days did not significantly differ between treatment groups (28 [10%] patients in the tenecteplase group and 23 [8%] in the control group; adjusted HR 1·29, 95% CI 0·74-2·26; p=0·37). Symptomatic intracranial haemorrhage occurred in six (2%) patients in the tenecteplase group versus three (1%) in the control group (adjusted OR 2·17, 95% CI 0·53-8·87; p=0·28), whereas any intracranial haemorrhage occurred in 33 (11%) versus 30 (10%) patients (adjusted OR 1·14, 0·67-1·94; p=0·64).

INTERPRETATION

In patients with wake-up stroke selected with non-contrast CT, treatment with tenecteplase was not associated with better functional outcome at 90 days. The number of symptomatic haemorrhages and any intracranial haemorrhages in both treatment groups was similar to findings from previous trials of wake-up stroke patients selected using advanced imaging. Current evidence does not support treatment with tenecteplase in patients selected with non-contrast CT.

FUNDING

Norwegian Clinical Research Therapy in the Specialist Health Services Programme, the Swiss Heart Foundation, the British Heart Foundation, and the Norwegian National Association for Public Health.

Adolescent Health Risk and Behavior Survey: A School Based Survey in Central Nepal

Background A comprehensive study of adolescent health risk specific to the Dhulikhel catchment area has not been performed. Objective This survey assesses trends in demographics, nutrition, hygiene and related infrastructure, causes of injury, violence, mental health, substance abuse, and menstrual hygiene. Method A 40 question survey was adapted from the Center for Disease Control (CDC) Youth Risk Behavior Surveillance System, translated into the Nepali language, and administered to 1200 students in eight different schools in central Nepal. Descriptive statistics were used to summarize the data. Result The data has identified nutrition, infrastructure, mental health, and menstrual hygiene as areas for improvement. The number of adolescents who reported going hungry some, most, or all of the time (30.5%, 25.8%, 13.9%) reveals a need for better food access. Approximately 44.5 % of students had no access to soap and water at school. Students who endorse dissatisfaction with themselves was 6.5% and those with suicidal ideation or attempt was 11.8% of the surveyed population. A significantly greater percentage of students who reported suicidal ideation also reported engaging in behaviors related to physical violence, substance abuse, being dissatisfaction with themselves, insomnia due to anxiety, and loneliness. Of the female students, 40.1% reported missing school at least once in the last three months due to their period. Conclusion This data shows a need for better food access, improved infrastructure in schools in central Nepal, and the need to address the prevalence of mental health issues through program interventions.

Blood circulating microparticle species in relapsing-remitting and secondary progressive multiple sclerosis. A case-control, cross sectional study with conventional MRI and advanced iron content imaging outcomes

BACKGROUND

Although multiple sclerosis (MS) is thought to represent an excessive and inappropriate immune response to several central nervous system (CNS) autoantigens, increasing evidence also suggests that MS may also be a neurovascular inflammatory disease, characterized by endothelial activation and shedding of cell membrane microdomains known as 'microparticles' into the circulation.

OBJECTIVE

To investigate the relationships between these endothelial biomarkers and MS.

METHODS

We examined the relative abundance of CD31(+)/PECAM-1, CD51(+)CD61(+) (αV-β3) and CD54(+) (ICAM-1) bearing microparticles in sera of healthy individuals, patients with relapsing-remitting MS, and secondary-progressive MS. We also investigated the correlation among circulating levels of different microparticle species in MS with conventional MRI (T2- and T1-lesion volumes and brain atrophy), as well as novel MR modalities [assessment of iron content on susceptibility-weighted imaging (SWI)-filtered phase].

RESULTS

Differences in circulating microparticle levels were found among MS groups, and several microparticle species (CD31(+)/CD51(+)/CD61(+)/CD54(+)) were found to correlate with conventional MRI and SWI features of MS.

CONCLUSION

These results indicate that circulating microparticles' profiles in MS may support mechanistic roles for microvascular stress and injury which is an underlying contributor not only to MS initiation and progression, but also to pro-inflammatory responses.

Cytomegalovirus disease in African-American kidney transplant patients

BACKGROUND

Cytomegalovirus (CMV) disease is a serious infection after kidney transplantation. The risk factors and the impact of CMV disease in African-American (AA) kidney transplant patients have not been well characterized.

METHODS

We performed a retrospective analysis on 448 AA patients transplanted between 1996 and 2005. A 3-month universal chemoprophylaxis with ganciclovir or valganciclovir was administered to CMV donor-positive/recipient-negative (D+/R-) patients and to those treated with anti-thymocyte globulin for rejection, but not routinely to those with other D/R serostatus.

RESULTS

A total of 31 AA patients (7%) developed clinical CMV disease. Compared with other D/R serostatus groups, the D+/R- group had the highest 3-year cumulative incidence of CMV disease (16.9% vs. 6.3% in D+/R+, 4.9% in D-/R+, and 2.4% in D-/R-). The D+/R- group also had the worst 3-year death-censored allograft survival (75% vs. 92% in D+/R+, 94% in D-/R+, and 96% in D-/R-, log-rank P = 0.01). Multivariate analysis found that D+/R- serostatus (odds ratio [OR] 5.4, 95% confidence interval [CI] 0.6-48.2, P = 0.003) and donor age > 60 years (OR 9.1, 95% CI 1.3-65, P = 0.03) were independent risk factors for CMV disease.

CONCLUSION

The D+/R- group has the highest incidence of CMV disease and the worst 3-year renal allograft survival despite 3-month universal prophylaxis. Prolonged chemoprophylaxis may be needed to prevent the late development of CMV disease and to improve allograft survival in the high-risk group of AA kidney transplant recipients.

Measured and modelled leaf and stand-scale productivity across a soil moisture gradient and a severe drought

Environmental controls on carbon dynamics operate at a range of interacting scales from the leaf to landscape. The key questions of this study addressed the influence of water and nitrogen (N) availability on Pinus palustris (Mill.) physiology and primary productivity across leaf and canopy scales, linking the soil-plant-atmosphere (SPA) model to leaf and stand-scale flux and leaf trait/canopy data. We present previously unreported ecophysiological parameters (e.g. V(cmax) and J(max)) for P. palustris and the first modelled estimates of its annual gross primary productivity (GPP) across xeric and mesic sites and under extreme drought. Annual mesic site P. palustris GPP was ∼23% greater than at the xeric site. However, at the leaf level, xeric trees had higher net photosynthetic rates, and water and light use efficiency. At the canopy scale, GPP was limited by light interception (canopy level), but co-limited by nitrogen and water at the leaf level. Contrary to expectations, the impacts of an intense growing season drought were greater at the mesic site. Modelling indicated a 10% greater decrease in mesic GPP compared with the xeric site. Xeric P. palustris trees exhibited drought-tolerant behaviour that contrasted with mesic trees' drought-avoidance behaviour.

Alterations in serum MMP-8, MMP-9, IL-12p40 and IL-23 in multiple sclerosis patients treated with interferon-β1b

Background: Interferon-β1b (IFN-β1b), an effective treatment for multiple sclerosis (MS), lessens disease severity in MS patients. However, the mechanisms of its immunoregulatory and anti-inflammatory effects in MS remain only partially understood. Matrix metalloproteinases (MMP) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) are involved in blood brain barrier disruption and formation of MS lesions. Th1/Th17 cytokines e.g. interleukins IL-12p40, IL-17, and IL-23, are associated with MS disease activity and are significant players in pathogenesis of MS.

Objective: During a 1-year prospective study, we serially measured serum MMP-8, MMP-9, TIMP-1, IL-12p40, IL-17, and IL-23 in 24 patients with relapsing—remitting MS. We compared the results to clinical course and to brain magnetic resonance imaging. IFN-β1b decreased serum MMP-8 and MMP-9 (not TIMP-1).

Results: The sustained treatment with IFN-β1b attenuated the pro-inflammatory environment by significantly reducing the serum IL-12p40, IL-23, and showed a trend for decreasing IL-17. Decreased serum MMP-8, MMP-9, IL-12 and IL-23 levels were correlated with a decrease in the number of contrast-enhanced T2-weighted lesions.

Conclusion: Early treatment of MS with IFN-β1b may stabilize clinical disease by attenuating levels of inflammatory cytokines and MMPs. Serial measurement of inflammatory mediators may serve as sensitive markers to gauge therapeutic responses to IFN-β1b during the first year of treatment.

Virilizing luteinized thecoma of the ovary in a 15-year-old female: a case report

BACKGROUND

Only 30% of luteinized thecomas are found in women under the age of 30, and they are typically benign. Only 11% of luteinized thecomas show clinical signs of androgen production. We present an unusual case of a 15-year-old female who presented with secondary amenorrhea and virilization and was subsequently diagnosed with a benign luteinized thecoma of the ovary. This is the youngest nonmalignant luteinized thecoma reported to date.

CASE

A 15-year-old Sri Lankan female presented with increasing hair growth, a hoarse voice, and secondary amenorrhea. On physical examination, there was marked hirsutism and clitoromegaly. Investigations found an elevated free testosterone level and an enlarged, homogenous left ovary with absent normal ovarian architecture. A laparotomy and unilateral salpingo-oophorectomy was performed. The final diagnosis was a luteinized ovarian thecoma, with no evidence of malignancy. Postoperatively, testosterone levels normalized and menstrual cycles resumed. Although laser treatment helped with her hirsutism, her other virilizing symptoms (deepening of voice, clitoromegaly) did not improve postoperatively.

CONCLUSION

This case of a virilizing ovarian luteinized thecoma emphasizes the need for timely evaluation, diagnosis, and treatment of patients presenting with symptoms of excess androgen secretion in order to avoid irreversible unwanted effects. Possible ovarian causes of excess androgen secretion should not be overlooked when considering possible causes of hyperandrogenism and secondary amenorrhea.

Prevention of auditory dysfunction in hypothyroid Tshr mutant mice by thyroxin treatment during development

Based on previous work, it is clear that genetically hypothyroid Tshr(hyt) mutant mice are congenitally deaf [O'Malley et al. (1995) Hear. Res. 88: 181-189, Sprinkle et al. 2001b, J. Assoc. Res. Otolaryngol. DOI: 10.1007/s101620010077]. However, the extent to which auditory development is dependent on the availability of thyroxin (T4) during specific developmental stages is unknown. The aim of this study was to determine the relative importance of prenatal and postnatal thyroxin on the ontogeny of hearing in the hyt mouse. Experimental hypothyroid subjects were offspring of hyt/hyt breeders implanted with T4 or placebo controlled-release pellets 14 days prior to mating. Pups received T4 or saline placebo injections from birth through postnatal day 14 (P14) or the time of testing on P28. In the absence of exogenous T4 replacement, very high stimulus levels (>80 dB SPL) were required to elicit responses. Remarkably, T4 treatment confined to the postnatal period failed to significantly improve auditory function relative to untreated animals, while response thresholds, latencies, and amplitudes of mice born to dams that received T4 during pregnancy were significantly improved relative to both of the untreated groups. Response thresholds were improved somewhat when maternal T4 replacement was followed by treatment during the first 14 days of life, and animals treated throughout prenatal and postnatal life were comparable to those of age-matched euthyroid individuals. Findings from this study show that treatment of hyt/hyt mice with exogenous T4 significantly attenuates hypothyroid-induced otopathology in a develop-mental-stage-dependent manner. In addition, we demonstrate that postnatal development is critically dependent on prenatal exposure to thyroxin and that the critical window of T4 dependence extends throughout development.

Consequences of hypothyroidism on auditory system function in Tshr mutant (hyt) mice

The otological consequences of hypothyroidism and the outcome of thyroxin (T4) administration during the developmental period preceding the onset of hearing were examined in mice that express a point mutation in the gene encoding the thyrotropin receptor (Tshr), the so-called hyt mouse. Progeny of sires homozygous for the trait and heterozygous dams were injected with T4 or saline placebo from birth through the tenth postnatal day and auditory-evoked brainstem responses (ABRs) to acoustic clicks and tone bursts were recorded from young adults. Mutant (hyt/hyt) mice exhibited a distinctive pattern of sensory pathology that was characterized by their insensitivity to sound, prolonged response latencies, reduced peak amplitudes, and steep latency-intensity curves relative to the phenotypically normal, euthyroid, +/hyt littermates. Following thyroxin treatment, hyt/hyt mice responded to acoustic stimuli more frequently, were more sensitive to tone bursts throughout their audiometric range, and exhibited decreased latencies and increased amplitudes when compared with placebo-treated homozygous mutants. Although thresholds to acoustic stimuli were improved relative to the untreated group, T4-treated homozygotes were less sensitive than normal, euthyroid individuals. In addition, energy consumption by auditory brainstem nuclei, measured by 2-deoxyglucose (2-DG) uptake, was significantly lower in hyt/hyt mice compared with heterozygotes, and T4 treatment increased the level of 2-DG utilization. Moreover, mean ages for eye-opening and pinna-raising were delayed in animals that were homozygous for the hyt allele. When T4 was administered to hyt/hyt animals, pinna-raising occurred earlier than in untreated animals. A subset of homozygotes exhibited circling behavior, indicative of vestibular and/or motor dysfunction, even though all individuals assumed a normal righting reflex. These findings, including recruitment-like behavior and the restoration of response magnitude at high levels but not low, suggest that the cochlear amplifier is the primary locus of an enduring otological defect associated with hypothyroidism in the Tshr mouse.

Development of auditory brainstem responses (ABRs) in Tshr mutant mice derived from euthyroid and hypothyroid dams

Developmental changes in auditory brainstem responses (ABRs) to clicks and tone bursts were studied in genetically hypothyroid Tshr mutant mice that were homozygous for the hypothyroid trait (hyt/hyt), as well as in euthyroid individuals that were heterozygous for the trait (+/hyt). The developmental role of maternal thyroid hormones was determined by comparing homozygotes that were offspring of euthyroid (hyt/hyt(c)) or hypothyroid (hyt/hyt(h)) dams; all heterozygotes were born to euthyroid dams (+/hyt(e)). Clear responses to high-level stimuli were recorded from heterozygotes on postnatal day 12 (P12) for most stimulus conditions, and thresholds, response amplitudes, interpeak intervals, and latencies developed normally, achieving nearly adult properties by P21. Most hyt/hyt(h) animals were unresponsive to acoustic stimulation throughout the period of study. Grossly immature responses to high-level stimuli were observed in many hyt/hyt(e) pups on P15; however, clear, low-amplitude responses were not routinely observed until P21. Thresholds improved with age in +/hyt(e) and hyt/hyt(e) individuals, and latency-level curves were relatively steep in young animals and developed normally in +/hyt(e) mice with the most significant changes occurring between P15 and P21. In general, hyt/hyt(e) mice exhibited prolonged latencies, interpeak intervals, and central conduction times throughout the age range studied, and slopes of latency-level curves remained abnormally steep through P28. Response amplitudes were generally larger in heterozygotes than in hyt/hyt(e) mice, regardless of level. Replacement of thyroxin during the first 10 postnatal days in hyt/hyt(h) pups had little to no effect on the development of auditory function, although more animals from this group were responsive at very high stimulation levels. We conclude that auditory function is impaired in hypothyroid Tshr animals throughout development and that impairment is profound when individuals are not exposed to maternal thyroid hormone, i.e., a clear thyroxin-dependent critical prenatal period exists in the Tshr mutant mouse.

Transperineal and transvaginal sonography of perianal inflammatory disease

OBJECTIVE

Perianal infection arises in small intersphincteric anal glands predominantly located at the dentate line. Documentation of fluid collections and the relationship of inflammatory tracts to the sphincter mechanism is important for surgical treatment. Transanal sonography for assessment of perianal inflammatory disease is limited because placement of the rigid probe into the anal canal does not allow assessment of disease in the perineal region. The purpose of this study was to validate the use of transperineal sonography in men and both transvaginal and transperineal sonography in women for evaluation of perianal inflammatory disease.

SUBJECTS AND METHODS

Fifty-four patients, 28 men and 26 women, were imaged with transperineal and a combination of transperineal and transvaginal sonography, respectively. All patients were examined in the supine lithotomy and left lateral position with a transvaginal 8-to 4-MHz probe or a linear 12- to 7-MHz transducer. All fluid collections, sinus tracts, and fistulas were described by their location in relation to the sphincter mechanism and perineum.

RESULTS

Forty-six of 54 patients had perianal fistulas or sinus tracts: 33 transphincteric, seven intersphincteric, and six extrasphincteric. Fifteen patients had an associated abscess. In the eight remaining patients, there were two anovaginal fistulas, one rectovaginal fistula, one prolapsed internal hemorrhoid, two perianal complex masses, and two vascular perianal or perirectal inflammatory masses. Twenty-six patients underwent surgical procedures involving the anorectal canal or perirectal region, and of these, preoperative sonographic findings were confirmed in 22 (85%) of 26 patients. Three patients refused surgery, and six are awaiting surgery at this writing. Fifteen patients were treated conservatively.

CONCLUSION

Transperineal and transvaginal sonography are accurate, painless, and cost-effective methods for documenting perianal fluid collections and fistulas or sinus tracts or both.

Physical management of spasticity

Physical management of people with spasticity is a complex task requiring the collaborative work of a multidisciplinary team. This article reviews some of the most commonly used treatment techniques and theories that lay the framework for the physical management of spasticity. Most crucial to the management of the person with spasticity is the skillful application of the techniques and theories discussed. Given the complexity in the standardized evaluation of children with spasticity, it is recommended that existing outcome measures or standardized scales be applied wherever possible as an adjunct tool to the clinician's assessment and interventions. One must recognize the benefits of such scales and their limitations. Therefore, it is recommended that further development of standardized assessments be supported by funding agencies to develop both quantitative and qualitative measurement tools that will address the particular needs of the person with spasticity. Review of the literature supports the many interventions that are listed; however, further research is recommended by the consensus group.

Wound botulism in California, 1951-1998: recent epidemic in heroin injectors

California has reported most of the world's wound botulism (WB) cases and nearly three-fourths of the cases reported in the United States. We reviewed the clinical, epidemiologic, and laboratory features of WB. From the first case in 1951, through 1998, a total of 127 cases were identified-93 in the last 5 years. The dramatic increase has been due to an epidemic (of WB) in people who inject black tar heroin. Whereas early cases of WB occurred after gross trauma, all but 1 of the last 102 cases occurred in drug users, primarily those who inject drugs subcutaneously ("skin poppers"). Cases are occurring disproportionately in Hispanics and women. Misdiagnosis and diagnostic delays of up to 64 days have occurred. This unprecedented, ongoing epidemic is now being reported in other states. We discuss the clinical and laboratory features that distinguish botulism from conditions that can mimic it, the relative yield of various diagnostic laboratory tests for botulism, and its treatment.

Afferent innervation of outer and inner hair cells is normal in neonatally de-efferented cats

It has been hypothesized that normal pruning of exuberant branching of afferent neurons in the developing cochlea is caused by the arrival of the olivocochlear efferent neurons and the resulting competition for synaptic sites on hair cells. This hypothesis was supported by a report that afferent innervation density on mature outer hair cells (OHCs) is elevated in animals deefferented at birth, before the olivocochlear system reaches the outer hair cell area (Pujol and Carlier [1982] Dev. Brain Res. 3:151-154). In the current study, this claim was evaluated quantitatively at the electron microscopic level in four cats that were de-efferented at birth and allowed to survive for 6-11 months. A semiserial section analysis of 156 OHCs from de-efferented and normal ears showed that, although de-efferentation essentially was complete in all four cases, the number and distribution of afferent terminals on OHCs was indistinguishable from normal, and the morphology of afferent synapses was normal in both the inner hair cell area and the OHC area. Thus, the postnatal presence of an efferent system is not required for the normal development of cochlear afferent innervation, and the synaptic competition hypothesis is not supported.

Variable pulmonary responses from exposure to concentrated ambient air particles in a rat model of bronchitis

Chronic bronchitis may be considered a risk factor in particulate matter (PM)-induced morbidity. We hypothesized that a rat model of human bronchitis would be more susceptible to the pulmonary effects of concentrated ambient particles (CAPs) from Research Triangle Park, NC. Bronchitis was induced in male Sprague-Dawley rats (90-100 days of age) by exposure to 200 ppm sulfur dioxide (SO2), 6 h/day x 5 days/week x 6 weeks. One day following the last SO2 exposure, both healthy (air-exposed) and bronchitic (SO2-exposed) rats were exposed to filtered air (three healthy; four bronchitic) or CAPs (five healthy; four bronchitic) by whole-body inhalation, 6 h/day x 2 or 3 days. Pulmonary injury was determined either immediately (0h) or 18 h following final CAPs exposure. The study protocol involving 0 h time point was repeated four times (study #A, November, 1997; #B, February, 1998; #C and #D, May, 1998), whereas the study protocol involving 18 h time point was done only once (#F). In an additional study (#E), rats were exposed to residual oil fly ash (ROFA), approximately 1 mg/ m(3)x6 h/day x 3 days to mimic the CAPs protocol (February, 1998). The rats allowed 18 h recovery following CAPs exposure (#F) did not depict any CAPs-related differences in bronchoalveolar lavage fluid (BALF) injury markers. Of the four CAPs studies conducted (0 h time point), the first (#A) study (approximately 650 microg/m3 CAPs) revealed significant changes in the lungs of CAPs-exposed bronchitic rats compared to the clean air controls. These rats had increased BALF protein, albumin, N-acetyl glutaminidase (NAG) activity and neutrophils. The second (#B) study (approximately 475 microg/m3 CAPs) did not reveal any significant effects of CAPs on BALF parameters. Study protocols #C (approximately 869 microg/m3 CAPs) and #D (approximately 907 microg/m3 CAPs) revealed only moderate increases in the above mentioned BALF parameters in bronchitic rats exposed to CAPs. Pulmonary histologic evaluation of studies #A, #C, #D, and #F revealed marginally higher congestion and perivascular cellularity in CAPs-exposed bronchitic rats. Healthy and bronchitic rats exposed to ROFA (approximately 1 mg/m3) did not show significant pulmonary injury (#E). Analysis of leachable elemental components of CAPs revealed the presence of sulfur, zinc, manganese, and iron. There was an apparent lack of association between pulmonary injury and CAPs concentration, or its leachable sulfate or elemental content. In summary, real-time atmospheric PM may result in pulmonary injury, particularly in susceptible models. However, the variability observed in pulmonary responses to CAPs emphasizes the need to conduct repeated studies, perhaps in relation to the season, as composition of CAPs may vary. Additionally, potential variability in pathology of induced bronchitis or other lung disease may decrease the ability to distinguish toxic injury due to PM.

The manifestation and nursing management of agitation in institutionalised residents with dementia

This participatory action research study is the first formal research study undertaken by nurses in a nursing development unit. The study emerged as the result of nurses brainstorming issues that they perceived to be problematic in their nursing practice and their unit environment. The nurses of the psycho-geriatric nursing development unit, Wallsend Aged Care Facility, New South Wales, Australia identified that the management of agitated behaviour manifested by their severely demented clients was a major challenge in their practice. As a result, a pilot participatory action research study was designed to measure how agitation manifested, to measure the severity of agitation and to identify current nursing practices used to manage it and their outcome. Results of the study demonstrated that nurse actions triggered the majority of most highly rated episodes of agitated behaviour in this group of elderly residents, and that the majority of these nurse actions related to those involved in carrying out activities of daily living for the residents.

SHP-2 can suppress transformation induced by platelet-derived growth factor

Signaling by either the type alpha or type beta receptors of platelet-derived growth factor occurs by phosphorylation of at least 10 intra-cytoplasmic tyrosine residues and their subsequent association of secondary signaling molecules with Src homology 2 (SH2) domains. Although the role of several of these secondary signaling molecules in mitogenesis has become increasingly clear, their roles in morphological transformation are not as well defined. Here we present evidence that the SHP-2 phosphatase which associates with Tyr 1009 of the type beta receptor and Tyr 720 of the type alpha receptor may suppress transformation induced by the PDGF B chain. Cotransfection of a dominant negative mutant of the SHP-2 gene and the PDGF B chain gene into mouse fibroblasts that only poorly formed foci with the PDGF B chain alone resulted in larger and more prominent foci. Furthermore, introduction of a wild-type copy of the SHP-2 gene into a tumor cell line, U-87MG, which relies on PDGF expression to form foci in vitro, caused a reversion of phenotype.

Contributions of ion conductances to the onset responses of octopus cells in the ventral cochlear nucleus: simulation results

The onset response pattern displayed by octopus cells has been attributed to intrinsic membrane properties, low membrane impedance, and/or synaptic inputs. Although the importance of a low membrane impedance generally is acknowledged as an essential component, views differ on the role that ion channels play in producing the onset response. In this study, we use a computer model to investigate the contributions of ion channels to the responses of octopus cells. Simulations using current ramps indicate that, during the "ramp-up" stage, the membrane depolarizes, activating a low-threshold K(+) channel, K(LT), which increases membrane conductance and dynamically increases the current required to evoke an action potential. As a result, the model is sensitive to the rate that membrane potential changes when initiating an action potential. Results obtained when experimentally recorded spike trains of auditory-nerve fibers served as model inputs (simulating acoustic stimulation) demonstrate that a model with K(LT) conductance as the dominant conductance produces realistic onset response patterns. Systematically replacing the K(LT) conductance by a h-type conductance (which corresponds to a hyperpolarization-activated inward rectifier current, I(h)) or by a leakage conductance reduces the model's sensitivity to rate of change in membrane potential, and the model's response to "acoustic stimulation" becomes more chopper-like. Increasing the h-type conductance while maintaining a large K(LT) conductance causes an increase in threshold to both current steps and acoustic stimulation but does not significantly affect the model's sensitivity to rate of change in membrane potential and the onset response pattern under acoustic stimulation. These findings support the idea that K(LT), which is activated during depolarization, is the primary membrane conductance determining the response properties of octopus cells, and its dynamic role cannot be provided by a static membrane conductance. On the other hand, I(h), which is activated during hyperpolarization, does not play a large role in the basic onset response pattern but may regulate response threshold through its contribution to the membrane conductance.

Clostridium difficile colitis associated with infant botulism: near-fatal case analogous to Hirschsprung's enterocolitis

We present the first five reported cases of Clostridium difficile-associated diarrhea (CDAD) in children with infant botulism caused by Clostridium botulinum. We compare two fulminant cases of colitis in children with colonic stasis, the first caused by infant botulism and the second caused by Hirschsprung's disease. In both children, colitis was accompanied by hypovolemia, hypotension, profuse ascites, pulmonary effusion, restrictive pulmonary disease, and femoral-caval thrombosis. Laboratory findings included pronounced leukocytosis, hypoalbuminemia, hyponatremia, coagulopathy, and, when examined in the child with infant botulism, detection of C. difficile toxin in ascites. CDAD recurred in both children, even though difficile cytotoxin was undetectable in stool after prolonged initial therapy. Four children who had both infant botulism and milder CDAD also are described. Colonic stasis, whether acquired, as in infant botulism, or congenital, as in Hirschsprung's disease, may contribute to the susceptibility to and the severity of CDAD.

Making survey results easy to report to consumers: how reporting needs guided survey design in CAHPS. Consumer Assessment of Health Plans Study

OBJECTIVES

CAHPS is designed to report information about health care quality from the consumer perspective. Enrollees are surveyed about their experiences with their health plan and medical care, and results are reported to other consumers choosing among health plans. Based on survey instruments designed to elicit reliable and valid information about health plan experiences from plan enrollees, the aim of the CAHPS team was to design a series of reporting products that present survey results so that consumers find the information understandable, meaningful, and useful in choosing among health plans.

METHODS

Design of the survey instruments and reporting products were closely linked. The approach to reporting was based on previous research on consumers' information interests and needs in evaluating and choosing among plans. Cognitive tests were conducted with consumers to get their reactions to mock-ups of various approaches to reporting CAHPS survey results.

RESULTS

Findings from previous research and cognitive testing, together with feedback from various experts and the public, were used to modify the survey questions, response options, and reporting formats to make it easier for consumers to understand and use reports. Changes included dropping topics of less interest to consumers, changing question wordings that were hard to understand, minimizing the number of different response categories, and revising questions to make them easier to group together for purposes of reporting.

CONCLUSIONS

The CAHPS focus on reporting results to consumers presented an unusual challenge for survey design, requiring close coordination between instrument design and report development to produce a survey and reporting kit that serves consumers' information needs.

Metabotropic glutamate receptor activation modulates sound level processing in the cochlear nucleus

The principal role of ionotropic glutamate receptors in the transmission and processing of information in the auditory pathway has been investigated extensively. In contrast, little is known about the functional contribution of the G-protein-coupled metabotropic glutamate receptors (mGluRs), although their anatomic location suggests that they exercise a significant influence on auditory processing. To investigate this issue, sound-evoked responses were obtained from single auditory neurons in the cochlear nuclear complex of anesthetized cats and gerbils, and metabotropic ligands were administered locally through microionophoretic pipettes. In general, microionophoresis of the mGluR agonists, (1S, 3R)-1-aminocyclopentane-1,3-dicarboxylic acid or (2S,1'S, 2'S)-2-(carboxycyclopropyl)glycine, initially produced a gradual increase in spontaneous and sound-evoked discharge rates. However, activation and recovery times were significantly longer than those observed for ionotropic agonists, such as N-methyl--aspartate or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, consistent with the recruitment of a second-messenger system. The efficacy of mGluR agonists was diminished after administration of the mGluR antagonist, (+)-alpha-methyl-4-carboxyphenylglycine, consistent with a selective action at metabotropic recognition sites. In contrast, two distinct changes were observed after the mGluR agonist had been discontinued for several minutes. Approximately 50% of neurons exhibited a chronic depression of sound-evoked discharge rate reminiscent of long-term depression, a cellular property observed in other systems. Approximately 30% of neurons exhibited a long-lasting enhancement of the sound-evoked response similar to the cellular phenomenon of long-term potentiation. These findings suggest that mGluR activation has a profound influence on the gain of primary afferent driven activity in the caudal cochlear nucleus.

Ultrastructural, physiological, and molecular defects in the inner ear of a gene-knockout mouse model for autosomal Alport syndrome

The cochleae from a COL4A3-deficient mouse line were examined for defects that might shed light on the molecular mechanism of otopathology observed in humans with Alport syndrome. At the light microscopic level no obvious defects were observed. Immunohistochemical analysis using antibodies specific for the basement membrane collagen chains revealed the absence of the COL4A3 and COL4A4 chains throughout the membranous labyrinth. The COL4A5 chain was absent from all cochlear basement membranes except those in the vessels of the stria vascularis. Expression of the COL4A1 and COL4A2 chains was unchanged in the mutant. Electron microscopic examination of the cochlear basement membranes revealed significant thinning of the basement membrane running from the spiral limbus, down the inner sulcus, across the basilar membrane and up to the spiral prominence. Basement membranes that normally ensheathe the root cells were not detectable. In contrast, the basement membranes surrounding the vessels of the stria vascularis were significantly thickened in the mutant. This was associated with endothelial cell swelling and a marked decrease in internal capillary diameter. In severe cases, pathology was observed in the marginal cells with a loss of basolateral infoldings. Immunohistochemical analysis of the strial vessels revealed an increase in entactin and collagen COL4A1 and COL4A2 chains. Auditory-evoked brainstem response measurements suggest a small increase in thresholds across all frequencies when successive measurements on individual mutant mice were examined between 6 and 8 postnatal weeks. Combined, these results illustrate changes in the basement membranes of the strial vessels that bear resemblance to Alport glomerular basement membrane pathology. A closer look at this compartment in human Alport biopsy specimen may be warranted.

Pulmonary responses to oil fly ash particles in the rat differ by virtue of their specific soluble metals

Occupational exposure to residual oil fly ash (ROFA) particulate has been associated with adverse respiratory health effects in humans. We hypothesized that ROFA collected at different sites within an oil burning power plant, by virtue of its differing metal and sulfate composition, will induce differential lung injury. Ten ROFA samples collected at various sites within a power plant were analyzed for water- and 1.0 M HCl-leachable arsenic (As), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), zinc (Zn), and sulfur by inductively coupled plasma-atomic emission spectroscopy. All ROFA samples contained variable amounts of leachable (water-extractable) and 1.0 M HCl-extractable Fe, V, and/or Ni. All other metals, except Zn (ROFA No. 1 contained 3.43 and No. 3, 6.35 micrograms/mg Zn), were present in negligible quantities (< 1.0 microgram/mg) in the water extract. In vivo pulmonary injury from exposure to whole saline suspensions of these ROFA was evaluated. Male, SD rats (60 days old) were intratracheally instilled with either saline or saline suspension of whole ROFA (< 3.0 mass median aerodynamic diameter) at three concentrations (0.833, 3.33, or 8.33 mg/kg). After 24 h, lungs were lavaged and bronchoalveolar lavage fluid (BALF) was analyzed for cellular influx and protein content as well as lactate dehydrogenase (LDH) and N-acetyl glucosaminidase (NAG) activity and total hemoglobin as indicators of lung injury. ROFA-induced increases in BALF protein and LDH, but not neutrophilic inflammation, were associated with its water-leachable total metal, Ni, Fe, and sulfate content. However, the neutrophilic response following ROFA exposure was positively correlated with its water-leachable V content. Modest lung injury was observed with the ROFA samples which contained the smallest amounts of water-leachable metals. The ability of ROFA to induce oxidative burst in alveolar macrophage (AM) was determined in vitro using a chemiluminescence (CL) assay. AM CL signals in vitro were greatest with ROFA containing primarily soluble V and were less with ROFA containing Ni plus V. In summary, ROFA-induced in vivo acute pulmonary inflammation appears to be associated with its water-leachable V content; however, protein leakage appears to be associated with its water-leachable Ni content. ROFA-induced in vitro activation of AM was highest with ROFA containing leachable V but not with Ni plus V, suggesting that the potency and the mechanism of pulmonary injury will differ between emissions containing V and Ni.

Long-term effects of sectioning the olivocochlear bundle in neonatal cats

The olivocochlear bundle (OCB) was cut in neonatal cats to evaluate its role in the development of normal cochlear function. Approximately 1 year after deefferentation, acute auditory nerve fiber (ANF) recordings were made from lesioned animals, lesion shams, and normal controls. The degree of deefferentation was quantified via light microscopic evaluation of the density of OCB fascicles in the tunnel of Corti, and selected cases were analyzed via electron microscopy. In the most successful cases, the deefferentation was virtually complete. ANFs from successfully lesioned animals exhibited significant pathophysiology compared with normals and with other animals in which the surgery failed to interrupt the OCB. Thresholds at the characteristic frequency (CF), the frequency at which ANFs are most sensitive, were elevated across the CF range, with maximal effects for CFs in the 10 kHz region. Frequency threshold or tuning curves displayed reduction of tip-to-tail ratios (the difference between CF and low-frequency "tail" thresholds) and decreased sharpness of tuning. These pathological changes are generally associated with outer hair cell (OHC) damage. However, light microscopic histological analysis showed minimal hair cell loss and no significant differences between normal and deefferented groups. Spontaneous discharge rates (SRs) were lower than normal; however, those fibers with the highest SRs remained more sensitive than those with lower SRs. Findings suggest that the interaction between OC efferents and OHCs early in development may be critical for full expression of active mechanical processes.

Wound botulism associated with black tar heroin among injecting drug users

CONTEXT

Wound botulism (WB) is a potentially lethal, descending, flaccid, paralysis that results when spores of Clostridium botulinum germinate in a wound and elaborate neurotoxin. Since 1988, California has experienced a dramatic increase in WB associated with injecting "black tar" heroin (BTH), a dark, tarry form of the drug.

OBJECTIVE

To identify risk factors for WB among injecting drug users (IDUs).

DESIGN

Case-control study based on data from in-person and telephone interviews.

PARTICIPANTS

Case patients (n=26) were IDUs who developed WB from January 1994 through February 1996. Controls (n=110) were IDUs newly enrolled in methadone detoxification programs in 4 counties.

MAIN OUTCOME MEASURES

Factors associated with the development of WB.

RESULTS

Among the 26 patients, the median age was 41.5 years, 15 (58%) were women, 14 (54%) were non-Hispanic white, 11 (42%) were Hispanic, and none were positive for the human immunodeficiency virus. Nearly all participants (96% of patients and 97% of controls) injected BTH, and the mean cumulative dose of BTH used per month was similar for patients and controls (27 g and 31 g, respectively; P=.6). Patients were more likely than controls to inject drugs subcutaneously or intramuscularly (92% vs 44%, P<.001) and used this route of drug administration more times per month (mean, 67 vs 24, P<.001), with a greater cumulative monthly dose of BTH (22.3 g vs 6.3 g, P<.001). A dose-response relationship was observed between the monthly cumulative dose of BTH injected subcutaneously or intramuscularly and the development of WB (chi2 for linear trend, 26.5; P<.001). In the final regression model, subcutaneous or intramuscular injection of BTH was the only behavior associated with WB among IDUs (odds ratio, 13.7; 95% confidence interval, 3.0-63.0). The risk for development of WB was not affected by cleaning the skin, cleaning injection paraphernalia, or sharing needles.

CONCLUSIONS

Injection of BTH intramuscularly or subcutaneously is the primary risk factor for the development of WB. Physicians in the western United States, where BTH is widely used, should be aware of the potential for WB to occur among IDUs.

Hearing loss in the RBF/DnJ mouse, a proposed animal model of Usher syndrome type IIa

The Usher syndromes (US) are a group of inherited disorders that feature autosomal recessive neurosensory hearing loss or deafness with retinitis pigmentosa (RP). Moderate to severe non-progressive high frequency hearing loss with RP and normal vestibular function describes Usher syndrome type IIa, which has been localized to 1q41. Severe retinal degeneration in the inbred mouse strain RBF/DnJ is caused by rd3, a recessive gene located on mouse chromosome 1 distal to akp1 in a region which is orthologous to human 1q32-q42. We evaluated rd3 as a candidate for orthology with USH2A by first reducing and refining the relatively broad region in which rd3 is thought to reside. DNA of offspring from an RBF/DnJ x MOLF/Ei backcross was genotyped with PCR markers closely flanking the predicted location of rd3. Our haplotype analysis re-positioned rd3 to a 3.6 cM region between markers D1Mit273 (cen) and D1Mit209 (tel), consistent with the expected position of an USH2A murine orthologue. Consequently, rd3 is a positional candidate for Usher type IIa. Next we assessed the rd3/rd3 audiological phenotype to see how closely it paralleled that of Usher IIa. Audiological evaluation of mice at various ages revealed evidence of high frequency progressive hearing loss, previously unreported in the RBF/DnJ strain. However, this newly discovered hearing deficit was observed to be inherited independently of rd3, establishing that a completely different gene is responsible.

Mechanisms of onset responses in octopus cells of the cochlear nucleus: implications of a model

The octopus cells of the posteroventral cochlear nucleus receive inputs from auditory-nerve fibers and form one of the major ascending auditory pathways. They respond to acoustic and electrical stimulation transiently and are believed to carry temporal information in the precise timing of their action potentials. The mechanism whereby onset responses are generated is not clear. Proposals aimed at elucidating the mechanism range from neural circuitry and/or inhibition, "depolarization block" (or inactivation of Na+ channels), and the involvement of a 4-aminopyridine (4-AP)-sensitive, low-threshold channel (K(LT)). In the present study, we used a compartment model to investigate possible mechanisms. The model cell contains a soma, an axon, and four passive dendrites. Four kinds of ionic channels were included in the soma compartment: the Hodgkin-Huxley-like Na+ and K+ channels, a 4-AP-sensitive, low-threshold channel, K(LT), and a Cs+-sensitive, hyperpolarization-activated inward rectifier, Ih. DC currents and half-wave-rectified sine waves were used as stimuli. Our results showed that an onset response can be generated in the absence of neuronal circuitry of any form, thus suggesting that the onset response in octopus cells is regulated intrinsically. Among the many factors involved, low-input impedance, partly contributed by Ih, appears to be essential to the basic onset response pattern; also, the K(LT) conductance plays a major role, whereas the inactivation of Na+ channels probably plays only a secondary role. The dynamics of Ih also can modify the response pattern, but due to its slow kinetics, its role is probably limited to longer-term regulation under the conditions simulated in this study.

A simple program for simulating the responses of neurons with arbitrarily structured and active dendritic trees

We describe a simple program to simulate neural responses. This program is based on the compartmental approach, in which all compartments of a neuron (i.e. axon, soma or dendrite) are represented by the same basic electrical structure. A parameter file is used to store the model parameters, including the nonlinear channel characteristics of each compartment. The model is then automatically configured according to the values specified in the parameter file. The computation of the conductance of each active channel over time is handled by a unique subroutine optimized according to the kinetics of each channel. The equations for arbitrarily structured trees are solved implicitly using a simple algorithm similar to that of Hines (Hines, M. (1984) Int. J. Biomed. Comput., 15:69-76). The output of the model uses PostScript format. The advantage of this program is that it is small in size, simple to use, efficient, and is platform independent.

Onset and development of auditory brainstem responses in the Mongolian gerbil (Meriones unguiculatus)

The ontogeny of auditory function in the Mongolian gerbil (Meriones unguiculatus) was examined by measuring auditory brainstem response (ABR) thresholds for clicks and tone bursts at frequencies between 0.125 and 32 kHz. ABRs were elicited as early as 10 postnatal days (PND) in a small proportion of animals (28.6%). Three phases of development were identified based on the appearance of frequency-threshold curves: (a) an onset period (10-12 PND) during which ABRs could be elicited only by intense stimuli (95-110 dB SPL) within a restricted range of frequencies (0.25-8 kHz); (b) a transition period (13-14 PND) during which thresholds improved but frequency-threshold curves remained relatively flat; and (c) a refinement period (15-30 PND) during which frequency-threshold curves exhibited an adult-like ('V') shape and thresholds improved steadily to adult-like values. Opening of the external auditory meatus was associated with threshold improvements but not with changes in the frequency region of greatest sensitivity. Between the ages of 13 and 21 PND, low-frequency (0.125-1 kHz) and high-frequency (10-32 kHz) thresholds improved at statistically equivalent rates (4.9 and 5.6 dB/day, respectively), while thresholds for mid-frequency stimuli (2-8 kHz) improved at a significantly faster rate of 9.2 dB/day.

Effects of stimulus rate on the feline brain-stem auditory evoked response during development. II. Peak amplitudes

The effects of click rate on brain-stem auditory evoked response (BAER) peak amplitudes were investigated in adult cats and kittens in four age groups: 10, 15, 20, and 30 post-natal days. Conventional BAERs were obtained at rates of 5, 10, 30, 60, and 90 Hz. Maximum length sequences (MLSs) were used to obtain responses at rates of 83, 125, 250, 500, and 1000 Hz. For both techniques, clicks were presented at 90 dB pSPL, and at 20 dB above threshold (20 dB SL). BAERs were observed for all age groups, at all click rates. However, not all peaks could be identified in all animals, with peak absence more common for the youngest kittens at the higher rates. BAER waves i through iv decreased in amplitude with increasing click rate for all age groups. In general, the smallest peak amplitudes were observed for the youngest animals (10- to 15-day-old) studied, while the largest amplitudes were found for the adult, 20- or 30-day-old animals, regardless of rate. When amplitudes were normalized to eliminate the influences of differences in absolute values due to developmental stage (i.e., made proportional to the amplitude observed at 5 Hz), the younger age groups exhibited enhanced sensitivity to the effects of stimulus rate. However, exceptions to this trend were observed. In general, amplitudes of BAER peaks obtained with the MLS procedure were smaller than those obtained using conventional averaging with a similar average click rate, regardless of age. Finally, the most efficient method for obtaining a response at a criterion signal-to-noise ratio was typically by the use of conventional averaging at a rate of 60 or 90 Hz, for all peaks and age groups, Overall, these data suggest that higher stimulus rates produce greater neural adaptation resulting in reduced BAER peak amplitudes. The mechanism responsible for the acquisition of adult-like adaptation properties appears to develop during the early post-natal period in the cat.

Effects of stimulus rate on the feline brain-stem auditory evoked response during development. I. Peak latencies

The effects of stimulation rate on the brain-stem auditory evoked response (BAER) of developing and adult cats were investigated. Age ranged from 10-post-natal days to young adults. Clicks were presented at levels of 90 dB pSPL and 20 dB above each animal's click threshold (20 dB SL). For all animals, a conventional BAER rate series was obtained at rates of 5, 10, 30, 60, and 90 Hz. BAERs were also obtained using pseudorandom pulse sequences called maximum length sequences (MLSs). The minimum time between pulses, the minimum pulse interval (MPI), included 0.5, 1, 2, 4, and 6 ms, which correspond to average rates of 1000, 500, 250, 125, and 83 Hz, respectively. Dependent variables included the latencies of the first four BAER peaks, labeled i through iv. MLS BAERs were indistinguishable from conventional BAERs at all ages studied. In general, for both conventional and MLS BAERs, peak latencies and the i-iv interval increased with increasing stimulus rate. Although absolute peak latencies and the i-iv interval decreased systematically with age, the relative shift in latency and i-iv interval induced by increasing stimulus rate decreased during development. The enhanced sensitivity to stimulus rate observed at younger ages was not the consequence of the threshold improvement that occurs during development since similar observations were made when stimuli were presented at a constant absolute level (90 dB pSPL) or at a constant level above threshold (20 dB SL). In addition, successive BAER peaks exhibited progressively larger latency shifts with increasing stimulus rate at all ages studied. These data suggest that higher stimulus rates produce greater neural adaptation resulting in prolonged BAER peak latencies. Furthermore, the effects of adaptation are cumulative across synapses, and the mechanisms responsible for the acquisition of adult-like adaptation properties develop during the early post-natal period in the cat.

Distortion generated by the ear: its emergence and evolution during development

Physiologically vulnerable active mechanics associated with the transduction of sounds in adults distort cochlear output. Specifically, frequencies not present in the incoming acoustic signal are represented in its output (ie., the spike trains of auditory nerve fibers). The purpose of this investigation was to study the appearance and evolution of intermodulation distortion during development. Established surgical and electrophysiologic techniques were used to record the extracellular electrical activity of individual auditory nerve fibers from developing kittens. Discharge-rate or synchrony-based responses to two tones (f1 and f2) presented simultaneously at various ratios of f2/f1 were recorded. The cubic distortion product (CDP; 2f1-f2, where f1<f2) and the difference tone (f2-f1) were the intermodulation distortion products (DPs) emphasized in the investigation. CDPs were first observed nearly 10 days after the earliest auditory nerve fiber responses to simple tone-burst stimuli could be elicited in neonatal cats. Furthermore, the spectrum of DPs generated in the cochlea changed dramatically during the second postnatal week and achieved adultlike characteristics after the first postnatal month. Findings reported here support the notion that cochlear transduction is initially linear in neonatal cats, possibly representing a critical period of auditory development, and that the content of distortion-related spectral information carried in auditory nerve fiber spike trains increases during development, in concert with other peripheral auditory attributes.

Employer-specific versus community-wide report cards: is there a difference?

This article describes preliminary results from a natural experiment that tested the impact of report cards on employees. As part of the 1995 enrollment process, some members of the State of Minnesota Employee Group Insurance Program received report cards on the plans offered to them, and others did not. Both groups of employees had a chance to review a second community-wide report card covering all Minnesota plans that had been distributed by an independent organization through local newspapers. Both groups were surveyed before and after they made their health plan selections. We compare the likelihood of seeing, the intensity of reading, and the perceived helpfulness of the first, employer-specific report card with the second, community-wide report card for consumers who make plan selections.

The digital toolbox for teaching

Continued improvements in computer technology have led to significant enhancement of clinical teaching. We describe a "digital toolbox" consisting of personally accessible hardware and software products to assist in clinical teaching. The areas covered are computer-assisted diagnosis, digitization and display of clinical materials, archiving of digitized clinical materials, and decision analysis. All products are commercially available, and none require special training or customization for medical teaching application.

Activity-dependent responses of developing cochlear nuclear neurons to microionophoretically-applied amino acids

The experimental purpose of this investigation was to determine whether the efficacy of glutamate, N-methyl-D-aspartate (NMDA) and/or GABA is related to the activity state of neurons in the cochlear nuclear complex (CN). The hypothesis tested was that changes in discharge activity produced by glutamatergic and GABAergic ligands are, or may be, greater when neurons are stimulated at moderate to high acoustic levels compared to near threshold stimulation levels, when activity levels are high or low, respectively. All neurons from which discharge rate vs. sound pressure level curves were tested during simultaneous administration of amino acids exhibited characteristics commensurate with an activity-dependent system; at high sound levels, when discharge rates were elevated relative to rates produced by low level stimuli, both glutamate-induced increments and GABA-induced decrements in discharge rate were enhanced. The relationship between discharge rate and amino acid efficacy was a uniform property of neurons sampled throughout the first two postnatal weeks of development. In adults, preliminary indications are that activity-dependent neurotransmitter efficacy is characteristic of some cells, but not others. The activity-dependent nature of endogenous amino acid neurotransmission was demonstrated through the microionophoretic administration of NMDA and GABAA selective antagonists, D-alpha-aminoadipate (D alpha AA) and 2-amino-5-phosphonovalerate (APV), and bicuculline (BIC), respectively. These results suggest that postsynaptic actions elicited by membrane receptors subserving amino acid neurotransmission within the CN are activity-dependent.

Health care report cards: what about consumers' perspectives?

Though the report card style is seen by many as a way to create better-informed consumers, very little is actually known about how consumers will respond to health care report cards. Report cards are only one of many factors that influence health care decision making. Much consumer-oriented effort and fine-tuning will be required to make report cards effective. Using the approach called "social marketing" as a framework, specific examples are used to outline some ideas for more intensive pursuit of consumers' perspectives in the design and distribution of report cards.

Responses of peripheral auditory neurons to two-tone stimuli during development: II. Factors related to neural responsiveness

In an accompanying paper (Fitzakerley et al., 1994), it was demonstrated that there is a significant developmental correlation between the appearance of tuning and two-tone suppression. However, it was also found that some sharply tuned neurons meeting minimal adult standards did not exhibit suppression. Therefore, in order to investigate other factors that may be related to the demonstration of suppression in peripheral auditory neurons, the relationship of two-tone suppression with various parameters related to neural responsiveness was studied in perinatal kittens. A positive correlation was made between the observance of suppression and driven discharge rate, characteristic frequency (CF), and threshold, all properties which change significantly during the final stages of cochlear differentiation. In older animals, suppression was also observed in higher percentages of neurons having low spontaneous rates (< 1 spk/s). Suppression was evoked less often by test tones placed below CF than above CF in neurons recorded from younger animals, and was generally produced by a narrower range of test tone intensities than those recorded from adults. As a result, the conventional description of suppression as observed in peripheral auditory neurons in mature animals must be extended to include these factors when responses of immature neurons are considered.