Complement depletion does not reduce brain injury in a rabbit model of thromboembolic stroke

The contribution of the complement system to cerebral ischemic and ischemia/reperfusion injury was examined in a rabbit model of thromboembolic stroke by delivery of an autologous clot embolus to the intracranial circulation via the internal carotid artery. A two-by-two factorial design was employed to study the impact of complement depletion via pretreatment with cobra venom factor (CVF, 100 U/kg i.v.) in the setting of permanent (without tissue plasminogen activator; t-PA) and transient (with t-PA) cerebral ischemia. Thirty-two New Zealand white rabbits were assigned to one of four groups (n=8, each group): control without t-PA, control with t-PA, CVF without t-PA and CVF with t-PA. In the complement intact animals, t-PA administration resulted in an approximate 30% reduction in infarct size when compared to the group not receiving t-PA (20.4+/-6.6% of hemisphere area vs. 30.1+/-7.2%; mean+/-SEM). However, infarct sizes in the complement depleted rabbits, with (30.7+/-8.2%) or without (30.2+/-7.9%) t-PA, were no different from the control group receiving no therapy. Similarly, no difference in regional cerebral blood flow or final intracranial pressure values was noted between any of the four groups. Complement activation does not appear to be a primary contributor to brain injury in acute thromboembolic stroke.

Juvenile angiofibroma: the lessons of 20 years of modern imaging

Seventy-two patients with juvenile angiofibroma have been investigated by computerized tomography (CT) and/or magnetic resonance imaging (MRI) over a period of 20 years. The evidence from these studies indicates that angiofibroma takes origin in the pterygo-palatine fossa at the aperture of the pterygoid (vidian) canal. An important extension of the tumour is posteriorly along the pterygoid canal with invasion of the cancellous bone of the pterygoid base, and greater wing of the sphenoid (60 per cent of patients). Distinctive features of angiofibroma are the high recurrence rate, and the rapidity with which many tumours recur. It is postulated that the principal determinant of recurrence is a high tumour growth rate at the time of surgery coupled with incomplete surgical excision. The inability to remove the tumour in toto is principally due to deep invasion of the sphenoid, as described above. In this series 93 per cent of recurrences occurred with this type of tumour extension. A contributory cause in these patients is the use of pre-operative embolization. The treatment implications of these findings are examined.

Distress symptoms among urban African American children and adolescents: a psychometric evaluation of the Checklist of Children's Distress Symptoms

OBJECTIVES

To explore the factor structure of the Checklist of Children's Distress Symptoms (CCDS); to examine whether there is a higher-order single construct underlying the CCDS measure; and, to assess the association between children's distress symptoms, as reflected by the CCDS factors, and children's self-reported exposure to community violence (both victimization and witness events).

DESIGNS

Community-based cross-sectional survey.

SETTINGS

Ten public housing developments in an eastern metropolis.

PARTICIPANTS

A total of 349 low-income urban African American children and adolescents (198 males; 151 females), 9 through 15 years of age.

MEASURES

Children's distress symptoms, exposure to community violence, and selected demographic information including parental education, parental employment status, perceived health status, and school performance.

ANALYSIS

Exploratory factor analysis was performed to determine the factorial structure of the CCDS measure. Second-order confirmatory factor analysis was performed to determine if there is a higher-order single underlying construct among CCDS factors. Pearson correlation coefficients were computed to assess the relationship between exposure to violence and CCDS factors.

MAJOR FINDINGS

The exploratory factor analysis yielded a 6-factor solution for the CCDS measure with satisfactory internal consistency. The confirmatory factor model with a single second-order construct yielded a good fit to the data. In general, youth who experienced violent victimization or witnessed violent events reported higher levels of distress symptoms than those who did not. Distress symptoms labeled as "intrusive thoughts," "distraction," and "lack of belongingness" were most frequently associated with exposure to violence. Distress symptoms did not differ on the basis of sex or age.

CONCLUSIONS

The CCDS has utility as a measure of distress symptoms among urban African American children and adolescents. Whereas analysis provided support for a single higher-order construct, using the proposed 6-factor structure should enhance our understanding of the psychological impact of exposure to violence on youth and contribute to more effective intervention efforts.

A functional neuroimaging description of two deep dyslexic patients

Deep dyslexia is a striking reading disorder that results from left-hemisphere brain damage and is characterized by semantic errors in reading single words aloud (e.g., reading 'spirit' as 'whisky'). Two types of explanation for this syndrome have been advanced. One is that deep dyslexia results from a residual left-hemisphere reading system that has lost the ability to pronounce a printed word without reference to meaning. The second is that deep dyslexia reflects right-hemisphere word processing. Although previous attempts to adjudicate between these hypotheses have been inconclusive, the controversy can now be addressed by mapping functional anatomy. In this study, we demonstrate that reading by two deep dyslexic patients (CJ and JG) involves normal or enhanced activity in spared left-hemisphere regions associated with naming (Broca's area and the left posterior inferior temporal cortex) and with the meanings of words (the left posterior temporo-parietal cortex and the left anterior temporal cortex). In the right-hemisphere homologues of these regions, there was inconsistent activation within the normal group and between the deep dyslexic patients. One (CJ) showed enhanced activity (relative to the normals) in the right anterior inferior temporal cortex, the other (JG) in the right Broca's area, and both in the right frontal operculum. Although these differential right-hemisphere activations may have influenced the reading behavior of the patients, their activation patterns primarily reflect semantic and phonological systems in spared regions of the left hemisphere. These results preclude an explanation of deep dyslexia in terms of purely right-hemisphere word processing.

Biased T-cell antigen receptor repertoire in Lyme arthritis

A common concern with many autoimmune diseases of unknown etiology is the extent to which tissue T-lymphocyte infiltrates, versus a nonspecific infiltrate, reflect a response to the causative agent. Lyme arthritis can histologically resemble rheumatoid synovitis, particularly the prominent infiltration by T lymphocytes. This has raised speculation about whether Lyme synovitis represents an ongoing response to the causative spirochete, Borrelia burgdorferi, or rather a self-perpetuating autoimmune reaction. In an effort to answer this question, the present study examined the repertoire of infiltrating T cells in synovial fluid from nine Lyme arthritis patients, before and after stimulation with B. burgdorferi. Using a highly sensitive and consistent quantitative PCR technique, a comparison of the T-cell antigen receptor (TCR) beta-chain variable (Vbeta) repertoires of the peripheral blood and synovial fluid showed a statistically significant increase in expression of Vbeta2 and Vbeta6 in the latter. This is remarkably similar to our previous findings in studies of rheumatoid arthritis and to other reports on psoriatic skin lesions. However, stimulation of synovial fluid T cells with B. burgdorferi provoked active proliferation but not a statistically significant increase in expression of any TCR Vbeta, including Vbeta2 and Vbeta6. Collectively, the findings suggest that the skewing of the TCR repertoire of fresh synovial fluid in Lyme arthritis may represent more a synovium-tropic or nonspecific inflammatory response, similar to that occurring in rheumatoid arthritis or psoriasis, rather than a specific Borrelia reaction.

Localization of bronchial intraepithelial neoplastic lesions by fluorescence bronchoscopy

BACKGROUND

In the treatment of lung cancer, the best outcome is achieved when the lesion is discovered in the intraepithelial (preinvasive) stage. However, intraepithelial neoplastic lesions are difficult to localize by conventional white-light bronchoscopy (WLB).

OBJECTIVE

To determine if autofluorescence bronchoscopy, when used as an adjunct to WLB, could improve the bronchoscopist's ability to locate and remove biopsy specimens from areas suspicious of intraepithelial neoplasia as compared with WLB alone.

METHOD

A multicenter clinical trial was conducted in seven institutions in the United States and Canada. WLB followed by fluorescence examination with the light-induced fluorescence endoscopy (LIFE) device was performed in 173 subjects known or suspected to have lung cancer. Biopsy specimens were taken from all areas suspicious of moderate dysplasia or worse on WLB and/or LIFE examination. In addition, random biopsy specimens were also taken from other parts of the bronchial tree.

RESULTS

The relative sensitivity of WLB + LIFE vs WLB alone was 6.3 for intraepithelial neoplastic lesions and 2.71 when invasive carcinomas were also included. The positive predictive value was 0.33 and 0.39 and the negative predictive value was 0.89 and 0.83, respectively, for WLB+LIFE and WLB alone.

CONCLUSION

Autofluorescence bronchoscopy, when used as an adjunct to standard WLB, enhances the bronchoscopist's ability to localize small neoplastic lesions, especially intraepithelial lesions that may have significant implication in the management of lung cancer in the future.

Heart rate variability reflects severity of COPD in PiZ alpha1-antitrypsin deficiency

BACKGROUND

Analysis of heart rate variability (HRV) is a powerful method of assessing severity of conditions affecting the autonomic nervous system.

STUDY OBJECTIVE

To determine if HRV is decreased and if HRV reflects severity in COPD.

DESIGN

Prospective determination of HRV from 24-h outpatient Holter recordings.

PATIENTS

Eighteen individuals with PiZ alpha1-antitrypsin deficiency: 13 with COPD and 5 with normal FEV1. HRV was also determined in 18 matched normal control subjects. Approximately 3 years after the initial recording, all COPD subjects were contacted to determine current status.

MEASUREMENTS

Indexes of heart rate (HR) and HRV were compared for groups of patients with and without COPD and their control subjects.

RESULTS

Mean and minimum HRs were higher in COPD patients. Virtually all indexes of HRV were significantly decreased in COPD patients. No differences were found in HR or HRV between PiZ individuals with normal FEV1 and their age-and gender-matched control subjects. Patients who had a change in status (ie, death, lung transplant, listed for transplant) had significantly higher daytime HRs, lower values for HRV indexes reflecting mixed sympathetic and parasympathetic modulation of HR, and reduced daytime high-frequency spectral power, an index of cardiac vagal modulation. Significant correlations (r=0.48 to 0.88) were found between FEV1 and these and other indexes of HRV. Most other indexes of HRV also tended to be lower for the group whose status had changed.

CONCLUSION

PiZ alpha1-antitrypsin deficiency COPD is associated with abnormal cardiac autonomic modulation. Indexes of HRV appear to reflect severity and may have prognostic value in COPD patients.

Medical examiner cases associated with previously undiagnosed diabetes mellitus, North Carolina, 1994

BACKGROUND

Approximately half of the 16 million Americans with diabetes mellitus (DM) are unaware they have the disease; the epidemiology of death from previously undiagnosed DM is unclear. We report medical examiner (ME) cases of death from DM in North Carolina in 1994 to determine the number and characteristics of these cases.

METHODS

Deaths from DM ICD-9 were identified and reviewed.

RESULTS

Of the 42 cases ascertained from ME records, 6 had previously undiagnosed DM, 5 had diabetes ketoacidosis, and 1 had nonketotic hyperosmolar hyperglycemia. Mean patient age at death for all cases was 42 years (range, 35 years to 57 years). Four patients felt bad at least 24 hours before death, indicating that they are not technically "sudden deaths."

CONCLUSIONS

We provide a limited epidemiologic perspective of the phenomenon of death from undiagnosed DM. We suggest further investigation of mortality from previously undiagnosed diabetes.

Treating word-finding difficulties--beyond picture naming

This paper presents some preliminary findings from research into the phonological treatment of word-finding difficulties in aphasia focusing on two areas of investigation. Firstly we report on the effects of giving a choice of phonological cues on word-finding. Secondly we describe our findings concerning the reliability of a measure of real-life interaction.

Possible nosocomial transmission of psittacosis

OBJECTIVES

To investigate a cluster of seven pneumonia cases among persons exposed to a pet-shop worker hospitalized with psittacosis.

DESIGN

Epidemiological study of the outbreak, sero-diagnostic evaluation of exposed persons with pneumonia; and retrospective review of the pneumonia cases.

SETTING

450-bed teaching community hospital.

PARTICIPANTS

Employees of the nursing unit where the patient with psittacosis was hospitalized.

RESULTS

The index case had laboratory and clinical evidence of psittacosis. Four of the seven exposed persons who developed pneumonia had serologic results that met criteria for a diagnosis of psittacosis, and three met criteria for Chlamydia pneumoniae infection, possibly reflecting cross-reactivity between the microimmunofluorescence assays for the two diseases. The epidemiological graph suggested a relationship between the index case and the cluster of pneumonias in exposed individuals.

CONCLUSIONS

Psittacosis may have been transmitted person to person in a hospital setting.

Fractionating the articulatory loop: dissociations and associations in phonological recoding in aphasia

This paper uses neuropsychological data to differentiate between three models of verbal short-term memory (Baddeley, 1983, 1986; Besner, 1987; Monsell, 1987). The focus is on three tasks: homophone judgments, rhyme judgments and pseudohomophone detection. When lesioned each model predicts characteristic patterns of impairment across these tasks. Thirteen span impaired aphasic subjects were assessed on all three tasks. The patterns of performance unequivocally supported the model proposed by Monsell (1987) which distinguishes input and output phonological buffers. Implications for further research are discussed.

Controlled trial of 4-ASA in ulcerative colitis

A six-week placebo-controlled trial of the efficacy and safety of 6 g per day of 4-aminosalicylic acid (4-ASA) was conducted in 30 subjects with mild to moderately severe ulcerative colitis. Subjects were stratified into groups having distal (< 60 cm) or more extensive (> 60 cm) disease. Diarrhea, bleeding, sigmoidoscopic and biopsy appearance, and physician global assessment were scored to judge efficacy. Safety was evaluated by monitoring untoward symptoms and laboratory values. Median percent improvement was significantly greater (P < 0.05) in the 4-ASA > 60-cm group (42.7%) than in the placebo > 60-cm group (21.2%), but 4-ASA was not better than placebo for the < 60-cm group or the total study group. Severe dyspepsia (one subject), abnormal AST (transient in five, persistent in one) and elevated lipase without pancreatitis (six subjects) were noted. Thus 6 g 4-ASA for six weeks was more effective than placebo in mild to moderate ulcerative colitis extending more than 60 cm above the anus, but not in distal disease, and the drug was generally well tolerated.

In vitro study of the mechanical effects of shock-wave lithotripsy

Impulsive stress in repeated shock waves administered during extracorporeal shock-wave lithotripsy (ESWL) causes injury to kidney tissue. In a study of the mechanical input of ESWL, the effects of focused shock waves on thin planar polymeric membranes immersed in a variety of tissue-mimicking fluids have been examined. A direct mechanism of failure by shock compression and an indirect mechanism by bubble collapse have been observed. Thin membranes are easily damaged by bubble collapse. After propagating through cavitation-free acoustically heterogeneous media (liquids mixed with hollow glass spheres, and tissue) shock waves cause membranes to fail in fatigue by a shearing mechanism. As is characteristic of dynamic fatigue, the failure stress increases with strain rate, determined by the amplitude and rise time of the attenuated shock wave. Shocks with large amplitude and short rise time (i.e., in uniform media) cause no damage. Thus the inhomogeneity of tissue is likely to contribute to injury in ESWL. A definition of dose is proposed which yields a criterion for damage based on measurable shock wave properties.

The effect of oral antiplatelet agents on tissue plasminogen activator-mediated thrombolysis in a rabbit model of thromboembolic stroke

OBJECTIVE

The success of thrombolytic therapy in acute stroke relies on timely reperfusion. The current study examines the efficacy of antiplatelet agents as adjuvants for thrombolytic therapy.

METHODS

Using an established rabbit model of clot embolization and a randomized blinded design, rabbits (n = 8 in each group) were orally pretreated daily for 5 days with adjuvant aspirin (1 mg/kg of body weight or 20 mg/kg), ticlopidine (100 mg/kg), or vehicle (sodium carbonate). On the 6th day, tissue plasminogen activator (6.3 mg/kg administered intravenously over 2 h), was initiated 1 hour after embolization.

RESULTS

In all groups, cerebral blood flow (CBF) was reduced to < 10 ml/100 g/min immediately after clot embolization. After the initiation of tissue plasminogen activator (t-PA), there was significant restoration of CBF in the control (t-PA only) and ticlopidine groups (P < 0.05) only. Restoration of CBF generally correlated with brain infarct size (percent hemisphere, mean +/- standard error of the mean), which was 18.0 +/- 7.0 in the t-PA only group versus 11.0 +/- 3.3, 26.5 +/- 5.8, and 21.5 +/- 3.4 in the ticlopidine, low-dose aspirin, and high-dose aspirin groups, respectively (ticlopidine versus aspirin, P < 0.05). Clot lysis was identical in the control and ticlopidine groups, with 6 of 8 animals demonstrating complete clot lysis. Aspirin antagonized clot lysis in a dose-related manner, with low-and high-dose aspirin groups noting clot lysis in four of eight and two of eight animals, respectively.

CONCLUSIONS

Pretreatment with ticlopidine significantly reduced brain infarct size when compared with aspirin treatment (P < 0.05). Moreover, whereas ticlopidine treatment did not affect clot lysis or CBF relative to t-PA alone, aspirin therapy resulted in antagonism of clot lysis and was associated with a more modest restoration of blood flow. This study provides a background for a more comprehensive understanding of the balance of thrombogenicity and thrombolysis and may assist in the development of novel therapies to expedite cerebrovascular patency and reduce ischemic and reperfusion-mediated neuronal injury.

Successfully treated invasive pulmonary aspergillosis associated with smoking marijuana in a renal transplant recipient

Invasive pulmonary aspergillosis (IPA) is often a lethal entity in transplant recipients (up to 90%). We report the successful treatment of a case of IPA in a renal transplant recipient whose only risk for exposure was habitual marijuana smoking. Although marijuana smoking has been linked to the development of IPA in patients immunosuppressed for a variety of reasons, this case is the first report involving a solid organ transplant recipient. The patient's clinical course and treatment are described and the literature is reviewed with respect to environmental and patient risk factors. In this case, IPA was associated with the patient's heavy usage of marijuana during the immediate posttransplant period. Treatment was successful and included the experimental amphotericin product amphotericin B colloidal dispersion. Contemporaneous exposure to a large amount of inocula of Aspergillus within 30 days of receiving high doses of steroids appeared to be the most important factor that predisposed this patient to IPA. Transplant recipients should be specifically proscribed from marijuana use during periods of high steroid administration.

Time-based lag sequential analysis and the functional assessment of challenging behaviour

This paper describes the application of time-based lag sequential analysis to the functional assessment of challenging behaviours shown by people with severe learning disabilities. The potential uses of the approach are illustrated with regards to identifying: (1) aspects of the stimulus control of challenging behaviour; (2) antecedents to the occurrence of challenging behaviour; and (3) the environmental consequences of challenging behaviour. The uses and limitations of the approach are discussed.

Hearing and saying. The functional neuro-anatomy of auditory word processing

The neural systems involved in hearing and repeating single words were investigated in a series of experiments using PET. Neuropsychological and psycholinguistic studies implicate the involvement of posterior and anterior left perisylvian regions (Wernicke's and Broca's areas). Although previous functional neuroimaging studies have consistently shown activation of Wernicke's area, there has been only variable implication of Broca's area. This study demonstrates that Broca's area is involved in both auditory word perception and repetition but activation is dependent on task (greater during repetition than hearing) and stimulus presentation (greater when hearing words at a slow rate). The peak of frontal activation in response to hearing words is anterior to that associated with repeating words; the former is probably located in Brodmann's area 45, the latter in Brodmann's area 44 and the adjacent precentral sulcus. As Broca's area activation is more subtle and complex than that in Wernicke's area during these tasks, the likelihood of observing it is influenced by both the study design and the image analysis technique employed. As a secondary outcome from the study, the response of bilateral auditory association cortex to 'own voice' during repetition was shown to be the same as when listening to "other voice' from a prerecorded tape.

Aphasic naming: what matters?

This paper investigates the factors which affect naming performance for two groups of aphasic subjects. The effects of word age-of-acquisition, operativity, frequency, familiarity, imageability, concreteness, length and the visual complexity of the stimulus picture were examined. In contrast to previous studies, we found remarkably small effects of word frequency on naming performance; these studies, we argue, have failed to control sufficiently for the effects of variables which intercorrelate with frequency. However, many patients were significantly affected by age-of-acquisition even when any effects of frequency and familiarity had been accounted for. Operativity, imageability and word length were also predictive of naming performance for some of the patients investigated, unlike visual complexity. The applicability of conclusions drawn from groups of aphasics is again thrown into doubt, as these two groups showed different patterns of predictor variables, and the variables affecting the performance of individuals could be different from those affecting the group.