Heparin-induced thrombocytopenia: An update for the COVID-19 era.

The increased use of heparin during the current COVID-19 pandemic has highlighted the risk of a rare but potentially serious complication of heparin therapy, viz. heparin-induced thrombocytopenia (HIT). This is a short review on the pharmacology of heparin and its derivatives, and the pathophysiology of HIT. Guidance on laboratory testing for and clinical management of HIT is presented in accordance with international guidelines. There are important similarities and differences between HIT and the new entity of vaccine-induced immune thrombotic thrombocytopenia, also known as thrombosis with thrombocytopenia syndrome, which clinicians need to be aware of.

Establishing local reference intervals for full blood count and white blood cell differential counts in Cape Town, South Africa.

BACKGROUND: Accurate laboratory reference intervals (RIs) are essential to differentiate between health and disease. There are variations in haematological indices within populations relating to gender, age, ethnicity and environment. Iron deficiency is common, has a wide range of clinical morbidities and affects red cell indices. Locally derived RIs for full blood count (FBC) parameters are needed for the Western Cape region of South Africa, after the exclusion of iron deficiency. In addition, information regarding the prevalence of iron deficiency in first-time blood donors would inform blood transfusion services regarding policies to screen for and treat iron deficiency. OBJECTIVES: To establish locally derived RIs for FBC and white blood cell (WBC) differential count parameters in healthy adults in the Cape Town area, by including first-time blood donors and excluding those with iron deficiency and thalassaemic indices. These new locally established RIs could update those in use by the local National Health Laboratory Service. A secondary objective was to establish the prevalence of iron deficiency in first-time blood donors. This would inform blood donation policies regarding screening and appropriate iron supplementation in high-risk groups prior to blood donation. METHODS: This was a prospective, descriptive study with direct convenience sampling. Participants were prospective voluntary blood donors aged between 18 and 60 years, presenting for first-time blood donation. Ethnicity was self-identified. Participants who tested positive for HIV or hepatitis B and/or C viruses were excluded. Prospective participants with iron deficiency, defined by serum ferritin levels below the RI, and those with red cell indices suggestive of an underlying thalassaemia trait were excluded. FBC samples were analysed using a Sysmex XN-1000 cell counter. Statistical non-parametric methods were used to calculate the RIs, according to international guidelines. RESULTS: Of the 774 participants screened, 82 (11%) had iron deficiency and were excluded. Six hundred and sixty-two patients were included for analysis, 409 (62%) female and 253 (38%) male. The majority of the participants, 348 (53%), were between 20 and 29 years of age, with a mean age of 29 years for females and 28 years for males. Participants comprised a mix of the various ethnic groups residing in Western Cape Province. The mean haemoglobin concentration for females was lower than that for males (p<0.0001). There were significant gender differences for total WBC count, absolute neutrophil count and platelet count, with females having higher counts than males. CONCLUSIONS: Locally established, population-specific RIs are essential for the accurate interpretation of haematological indices. This study established locally derived gender-specific RIs for the Cape Town region, after exclusion of iron deficiency. These new RIs have implications for the accurate diagnoses of cytopenias, cytoses and other blood count abnormalities. Iron deficiency is common in first-time blood donors, and screening for iron deficiency using point-of-care testing should be considered.

The utility of bone marrow sampling in the diagnosis and staging of lymphoma in South Africa.

INTRODUCTION: The bone marrow biopsy (BMB) is a diagnostic and staging tool in lymphoma that remains practically useful and relevant in resource-constrained settings, despite restricted applications in international staging guidelines, which favour less invasive nuclear medicine techniques. METHODS: Retrospective laboratory data review of BMBs in adult lymphoma patients from 2005 to 2010 to determine subtypes, rates of bone marrow involvement (BMI), human immunodeficiency virus (HIV) seroprevalence and CD4 counts, trephine length and additional findings. RESULTS: A total of 1215 BMBs reported in lymphoma included 759 newly diagnosed patients, with BMI in 43.6% of non-Hodgkin lymphoma (NHL) overall, 28.9% of high-grade B subtypes and 35.7% of Hodgkin lymphoma (HL). HIV seroprevalence was 38.8%, 53.0% and 33.9% in the 3 respective groups. There was a statistical association between BMI and HIV seropositivity in Burkitt lymphoma and HL, and BMI and CD4 count in HIV-related HL. Over 10% (n = 79) of new lymphoma cases were diagnosed by BMB with ancillary tests. Occasional histological discordance and transformation were reported in NHL. Focal/unilateral BMI was uncommon. Bilateral BMB and biopsy length exceeding 26 mm did not improve BMI detection. CONCLUSION: In the South African public sector, high HIV prevalence leads to a different lymphoma pathology profile from the developed world. High BMI rates are encountered. Here, and in similar resource-constrained settings, international lymphoma staging guidelines can be logistically challenging and unaffordable. BMB remains useful in the staging and diagnosis of lymphoma. Unilateral sampling with a processed trephine length of at least 26 mm is recommended.

Anaemia in patients with HIV-associated TB: relative contributions of anaemia of chronic disease and iron deficiency.

BACKGROUND: Anaemia commonly complicates both human immunodeficiency virus (HIV) infection and tuberculosis (TB), contributing substantially to morbidity and mortality. The mechanisms underlying anaemia and corresponding treatments in co-infected patients are poorly defined. OBJECTIVE: To determine the relative contributions of anaemia of chronic disease (ACD) and iron deficiency to anaemia in patients with HIV-associated TB. DESIGN: Consecutively recruited hospitalised (n = 102) and matched ambulatory patients (n = 51) with microbiologically confirmed HIV-associated TB in Cape Town, South Africa, were included. Haemoglobin levels, iron status markers, hepcidin and pro-inflammatory cytokines in blood were measured. We determined the prevalence of ACD and iron-deficiency anaemia (IDA) using seven different published definitions of IDA. RESULTS: More than 80% of enrolled HIV-associated TB patients were anaemic, and anaemia was more severe among in-patients. Over 95% of anaemic HIV-associated TB patients had ACD, whereas the proportion with IDA using a range of seven different definitions was low overall (median <3%, range 0-32.6) in both patient groups. The proportion with IDA and hepcidin concentration â©¿ 20.0 ng/ml (predictive of responsiveness to oral iron supplementation) was also very low (median <3%, range 0-15.1). CONCLUSIONS: ACD was the predominant cause underlying anaemia in HIV-associated TB patients, and IDA was very uncommon in this setting. The majority of anaemic HIV-associated TB patients were unlikely to benefit from oral iron supplementation.

The diagnostic utility of bone marrow biopsies performed for the investigation of fever and/or cytopenias in HIV-infected adults at Groote Schuur Hospital, Western Cape, South Africa.

INTRODUCTION: A bone marrow biopsy is frequently requested in the work-up of patients with human immunodeficiency virus (HIV) infection who present with fever and/or cytopenias in the search for opportunistic infections and malignancies. METHODS: This is a retrospective review of the results of consecutive bone marrow biopsies performed at our institution over a three-year period on HIV-positive patients for the investigation of fever and/or cytopenias. Clinical data, haematological parameters, morphological features, Ziehl-Neelsen staining and microbiological culture results were analysed. The aim of the study was to determine the diagnostic yield of this investigation. RESULTS: Sixty-three males and 84 female patients were included for analysis. The bone marrow biopsy gave a high diagnostic yield of 47% (70 patients) and a unique diagnosis in 33% (49 patients). Immune thrombocytopenic purpura and disseminated mycobacterial infections were the most common unique diagnoses made (14%, respectively), followed by malignancies (4%). In this cohort, four cases of primary bone marrow involvement by Hodgkin lymphoma and one case of involvement by non-Hodgkin lymphoma were diagnosed. CONCLUSION: In our study group, a bone marrow biopsy was a useful investigation with a high diagnostic yield.

The vibrant soundbridge for conductive and mixed hearing losses: European multicenter study results.

BACKGROUND/AIMS: The Vibrant Soundbridge (VSB) is an active middle ear implant, 'direct-drive' hearing system for the treatment of hearing loss. Recently, the VSB has been applied to conductive and mixed hearing losses. The aim of this study is to evaluate aided benefit, speech recognition in quiet and noise, subjective benefits, changes in residual hearing, and medical and surgical complications in adults with conductive or mixed hearing losses implanted with the VSB using Round Window (RW) Vibroplasty. METHODS: Twelve German-speaking adults participated in a single-subject, repeated measures study design comparing their performance using the VSB with their own unaided preoperative performance. Hearing performance and changes in residual hearing were assessed using routine audiometric measures, sound field thresholds, and word and sentence recognition in quiet and in noise. Subjective benefits, including subjective hearing performance, device satisfaction, and quality of life were evaluated using the Abbreviated Profile of Hearing Aid Benefit, the Hearing Device Satisfaction Scale, and the Glasgow Benefit Inventory, respectively. RESULTS: Aided hearing thresholds, word recognition at conversational levels, and sentence recognition in quiet and noise were significantly improved without significant changes in residual cochlear hearing and without major medical and surgical complications. One subject required repositioning surgery to improve transducer coupling with the RW membrane. Subjective benefit and device satisfaction were good, as were overall and general quality of life. CONCLUSION: The VSB, implanted using RW vibroplasty, is a safe and effective treatment for adults with conductive and mixed hearing losses who may have few, if any, other options.

Monocusp - novel common femoral vein monocusp surgery uncorrectable chronic venous insufficiency with aplastic/dysplastic valves.

OBJECTIVE: Previous reparative valvular surgical options directed at reconstructing damaged common femoral vein (CFV) valves associated with pathological chronic venous insufficiency (CVI) have not succeeded in reliably managing CVI. In consequence, venous valvuloplasty is rare and most patients are managed conservatively. As a result, monocusp surgery was identified as an optional surgical solution for this large underserved patient group. METHODS: Ulcer patients appear at wound clinics and often experience disappointing results. Monocusp valves were constructed utilizing viable vein wall in 14 operations on 11 patients. These patients were observed for four years to see if such an autogenous vein wall valve might control aggressive symptomatic CVI when faced with unusable valves. RESULTS: Long-term follow-up showed that the monocusp valves remained competent at four years. Symptomatic failures have not appeared at this time. Pain, swelling, ulcers and leg congestion were reliably reversed. VEnous INsufficiency Epidemiologic and Economic Study (VEINES) classification (see Abenhaim L, Krux X, VIENES Study collaborators. Angiology 1997;48:59 and Kurz X, Kahn SR, Abenhaim L, et al. Int Angiol 1999;18:83-102) improved over four years from 2.7 +/- 0.9 to 0 (P < 0.001); CEAP classifications (see Kistner RL, Eklof B, Masuda EM. Mayo Clin Proc 1996;71:338-45) improved from grade 4-6 to 0-1 (CEAP is not generally a postoperative grading system, but it can be used to develop some form of qualitative analyses as to intervention effectiveness, i.e. what existed preoperatively no longer exists postoperatively. Its postsurgery use is limited by (C5) classification - history of ulcer, which by definition cannot go below that with a history of ulcer even if the ulcer has been cured). Mean venous reflux scores decreased from 3.8 +/- 0.4 to 0.3 +/- 0.5 (P < 0.001). CONCLUSION: Monocusp implantation reliably resolved patient symptoms when unusable CFV valves were encountered. Postoperative CFV reflux is usually undetectable. The monocusp valve exhibits minimal thrombogenicity related to its viability with attendant antithrombotic hormone production capacity and has markedly improved the patient's quality of life. Full thickness monocusp surgery could become widespread with the difficult dysplastic/aplastic CVI patient subset because of its simplicity, repeatability, durability, low complication rate, effectiveness, persistent availability and viability providing nitric oxide synthase and thymomodulin hormone production capacity. The full thickness of vein wall has distinct advantages over other partial thickness valve creation methods because of its long-term vitality. Postoperative coumadin is recommended for six months to minimize risks of deep vein thrombosis and/or pulmonary embolism.

A comparison of the efficacy and safety of olanzapine and risperidone in the treatment of elderly patients with schizophrenia: an open study of six months duration.

BACKGROUND: Following an earlier study in which elderly patients with schizophrenia had their typical antipsychotic medication changed to olanzapine or risperidone, the 61 patients were followed for up to a further six months to see if either treatment was superior in terms of efficacy or side effects. AIMS: To determine whether either olanzapine or risperidone was superior in terms of efficacy or side effects when treating schizophrenia in late life. METHODS: Psychiatric symptoms, side effects and quality of life were rated every six weeks for 24 weeks of open label comparative treatment using standard measures. Group differences were examined using analysis of covariance and within-group changes over time were assessed using paired t-tests. RESULTS: There were 34 olanzapine and 32 risperidone patients who entered the study, but intention to treat data was only available for 61 of the 66 patients. There were no clinical or demographic differences between the groups. Parkinsonism, positive and negative symptoms of schizophrenia improved in both groups both from baseline switch to olanzapine or risperidone and during the six month follow-up after completion of crossover. No significant differences were seen between groups on most measures. However, patients treated with olanzapine showed a significantly greater improvement in quality of life from baseline compared to risperidone patients. CONCLUSIONS: Both drugs were well tolerated and their use was associated with fewer symptoms of schizophrenia and less adverse effects than were seen when the patients were taking a typical antipsychotic at baseline. Olanzapine appears to have particular benefit with regard to quality of life.

The impact upon extra-pyramidal side effects, clinical symptoms and quality of life of a switch from conventional to atypical antipsychotics (risperidone or olanzapine) in elderly patients with schizophrenia.

BACKGROUND: Atypical antipsychotics are commonly used in the management of schizophrenia in late life with evidence suggesting they induce lower rates of motor disturbance, but have similar efficacy to conventional antipsychotics. Trials in the elderly have been either retrospective, small, of short duration or of a single-arm design. AIMS: To demonstrate the effects upon motor side-effects, efficacy, safety and quality of life (QOL) of switching elderly patients with schizophrenia from conventional antipsychotics to olanzapine or risperidone. METHODS: Elderly patients with schizophrenia were randomly allocated to olanzapine or risperidone and followed through an open-label crossover period. Between and within group intention to treat analyses were conducted. RESULTS: 66 patients were randomised (mean age 69.6 [SD +/- 6.2]). Four (11.8%) patients on olanzapine and 8 (26.7%) patients on risperidone failed to complete the crossover because of treatment failure [Odds Ratio (OR) = 2.73[0.73-10.2] p = 0.14]. The mean doses upon completion of switching in each arm were 9.9 mg (SD = 4.2) and 1.7 mg (SD = 1.2) for olanzapine and risperidone respectively. In both arms there was improvement in Parkinsonism, though only olanzapine was associated with a reduction in dyskinetic symptoms. The Brief Psychiatric Rating Scale, Scale for the assessment of Negative Symptoms and Montgomery and Asberg Depression Rating Scale scores all improved through the crossover period in both arms with no between group differences. Treatment with olanzapine was associated with a better response over risperidone on the psychological domain of the World Health Organisation-Quality Of Life [Brief] (WHO-QOL-BREF) scale ( p = 0.02). Patients in the olanzapine arm also demonstrated improvement from baseline in the WHO-QOL-BREF physical, psychological and health satisfaction domains, but risperidone had no effect on any Quality of Life (QOL) measure. CONCLUSIONS: After switching from a conventional antipsychotic, olanzapine and risperidone were associated with improvement in core symptoms of schizophrenia and motor side effects. Subjects switched to olanzapine were more likely to complete the switching process and show an improvement in psychological QOL.

The effect of long-term deafness on speech recognition in postlingually deafened adult CLARION cochlear implant users.

Research suggests that duration of deafness prior to cochlear implantation affects postoperative speech recognition in adults. Duration of deafness usually is defined as the number of years between the onset of profound deafness and implantation. The purpose of this study was to examine the effects of duration of deafness--expressed as percentage of life with deafness--independent of age at implantation on postoperative speech recognition in adult postlingually deafened CLARION Multi-Strategy Cochlear Implant users. Speech recognition tests (CID sentences and NU6 words) were administered to 202 consecutively implanted adults preoperatively and at 3 and 6 months after initial device fitting. Patients implanted at a younger age and those with smaller percentages of their lives with deafness achieved the highest levels of short-term postoperative speech recognition. Patients who had been deaf for > or =60% of their lives demonstrated a slower rate of speech recognition improvement than those with shorter durations of deafness, but still continued to improve with increased implant experience.

A connectionist theory of phenomenal experience.

When cognitive scientists apply computational theory to the problem of phenomenal consciousness, as many have been doing recently, there are two fundamentally distinct approaches available. Consciousness is to be explained either in terms of the nature of the representational vehicles the brain deploys or in terms of the computational processes defined over these vehicles. We call versions of these two approaches vehicle and process theories of consciousness, respectively. However, although there may be space for vehicle theories of consciousness in cognitive science, they are relatively rare. This is because of the influence exerted, on the one hand, by a large body of research that purports to show that the explicit representation of information in the brain and conscious experience are dissociable, and on the other, by the classical computational theory of mind--the theory that takes human cognition to be a species of symbol manipulation. Two recent developments in cognitive science combine to suggest that a reappraisal of this situation is in order. First, a number of theorists have recently been highly critical of the experimental methodologies used in the dissociation studies--so critical, in fact, that it is no longer reasonable to assume that the dissociability of conscious experience and explicit representation has been adequately demonstrated. Second, classicism, as a theory of human cognition, is no longer as dominant in cognitive science as it once was. It now has a lively competitor in the form of connectionism; and connectionism, unlike classicism, does have the computational resources to support a robust vehicle theory of consciousness. In this target article we develop and defend this connectionist vehicle theory of consciousness. It takes the form of the following simple empirical hypothesis: phenomenal experience consists of the explicit representation of information in neurally realized parallel distributed processing (PDP) networks. This hypothesis leads us to reassess some common wisdom about consciousness, but, we argue, in fruitful and ultimately plausible ways.

The efficacy of psychosocial approaches to behaviour disorders in dementia: a systematic literature review.

OBJECTIVE: This paper provides a systematic review of research findings published between 1989 and 1998 concerning non-pharmacological strategies to alleviate behavioural disturbances in elderly persons with dementia. METHOD: Data collection strategies included computer literature searches, manual searches of selected journals and checks of references listed in previous reviews. To warrant inclusion, studies were required to include some measure of behaviour before and after the introduction of an intervention. Papers were appraised in the following domains: design, sampling technique, setting, behaviours studied, measurement tools, data collection methods, type of interventions and feasibility. An overall validity rating was assigned to each article using predetermined rules. RESULTS: Forty-three studies met criteria for inclusion including five randomised controlled trials. Validity ratings were as follows: one strong, 15 moderate, and 27 weak. Areas of scientific weakness included small numbers of subjects, inadequate descriptions of study participants, imprecise data collection methods, high attrition rates and insufficient statistical analysis. Despite this, there is evidence to support the efficacy of activity programs, music, behaviour therapy, light therapy, carer education and changes to the physical environment. The evidence in favour of multidisciplinary teams, massage and aromatherapy is inconclusive. CONCLUSIONS: It was easier to interpret the results of rigorously designed studies that focused on a single behaviour or single intervention tailored to the needs of individuals and carers. Future studies should seek to replicate the findings outlined here, improving methodologies where necessary and including outcome measures that encompass the interests of people with dementia, family caregivers and health professionals.

The effects of hearing loss and noise masking on the masking release for speech in temporally complex backgrounds.

Speech recognition was measured in three groups of listeners: those with sensorineural hearing loss of (presumably) cochlear origin (HL), those with normal hearing (NH), and those with normal hearing who listened in the presence of a spectrally shaped noise that elevated their pure-tone thresholds to match those of individual listeners in the HL group (NM). Performance was measured in four backgrounds that differed only in their temporal envelope: steady-state (SS) speech-shaped noise, speech-shaped noise modulated by the envelope of multi-talker babble (MT), speech-shaped noise modulated by the envelope of single-talker speech (ST), and speech-shaped noise modulated by a 10-Hz square wave (SQ). Threshold signal-to-noise ratios (SNRs) were typically best in the ST and especially the SQ conditions, indicating a masking release in those modulated backgrounds. SNRs in the SS and MT conditions were essentially identical to one another. The masking release was largest in the listeners in the NH group, and it tended to decrease as hearing loss increased. In 5 of the 11 listeners in the HL group, the masking release was nearly identical to that obtained in the NM group matched to those listeners; in the other 6 listeners, the release was smaller than that in the NM group. The reduced masking release was simulated best in those HL listeners for whom the masking release was relatively large. These results suggest that reduced masking release for speech in listeners with sensorineural hearing loss can only sometimes be accounted for entirely by reduced audibility.

Evaluation of electrically elicited stapedius reflex threshold measured through three different cochlear implant systems.

OBJECTIVE: To evaluate intraoperative electrically elicited stapedius reflex thresholds (ESRTs) measured through three different cochlear implant systems: the Nucleus Mini 22, the Clarion Enhanced Bipolar, and the Med-El Combi-40. SUBJECTS AND METHODS: Relations between intraoperative ESRT and postoperative maximum comfort level (MCL) were examined in seven children (4 Nucleus, 2 Clarion, and 1 Med-El) and one adult (Clarion). RESULTS: Preliminary results indicated most ESRTs were either higher or both higher and lower (across the electrode array within a subject) than MCLs. All systems provided satisfactory means for measuring ERSTs. CONCLUSION: It is recommended that hand-held systems have a direct readout to the programming station and that audio and visual feedback be improved for all units.

Monotic and dichotic modulation detection interference in practiced and unpracticed subjects.

The threshold for detecting 10-Hz amplitude modulation of a 1-kHz carrier was measured in quiet and in the presence of a 4-kHz masker carrier that was either unmodulated or amplitude modulated at a depth of 1.0 and at rates from 2 to 80 Hz. The signal and masker were presented to the same ear (monotic condition) or to opposite ears (dichotic condition), and the subjects either had no previous experience with psychoacoustic experiments (n = 10) or had from 16 to about 70 h of experience with modulation-detection tasks (n = 4). There were no significant differences between the two groups of subjects, although there was a significant effect of presentation mode. Thresholds generally were higher in the monotic condition, particularly when the masker rate was similar to the signal rate. According to excitation-pattern analyses, the greater interference in the monotic condition is unlikely due to peripheral interactions.

Warm blood cardioplegia.

Between 1990 and 1992, 346 consecutive patients underwent coronary artery bypass procedures. Ninety-eight patients (group A) from 1990 served as historical controls, and 248 patients (group B) from 1991 to 1992 served as a prospective, consecutive cohort for statistical comparison. The two groups varied in the type of myocardial protection used: intermittent cold crystalloid cardioplegia was used in group A and continuous warm blood cardioplegia in group B. (Two patients in group A received intermittent cold blood cardioplegia, and these 2 patients are grouped with the crystalloid group for the sake of convenience. The presence or absence of these 2 patients did not alter the group A statistics in any noticeable manner). Class IV high-risk groups demonstrated a 63% reduction in mortality (p = 0.07), and overall group B experienced a 28% reduction in mortality (4.4% versus 6.1%; p = not significant), an 86% reduction in perioperative myocardial infarction rate (1.6% versus 12.2%; p < 0.05), a 20% reduction in postoperative bleeding (275 versus 345 mL.day-1.m-2), and a marked reduction in reentry rates (p = 0.05). Also noted was a 32% reduction in postoperative ventilation requirements (25 versus 37 hours; p = 0.05). Less inotrope was required and intraoperative stroke was not seen in the patients with warm blood cardioplegia. Group B patients were less likely to have development of complex postoperative arrhythmias. Ventricular fibrillation at unclamping was noticeably rare (2.0% in group B versus 84% in group A; p < 0.05). The average group B heart resumed sinus rhythm 72 seconds after declamping.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of amplitude comodulation on auditory object formation in sentence perception.

To comprehend speech in most environments, listeners must combine some but not all sounds from across a wide range of frequencies. Three experiments were conducted to examine the role of amplitude comodulation in performing an essential part of this function: the grouping together of the simultaneous components of a speech signal. Each of the experiments used time-varying sinusoidal (TVS) sentences (Remez, Rubin, Pisoni, & Carrell, 1981) as base stimuli because their component tones are acoustically unrelated. The independence of the three tones reduced the number of confounding grouping cues available compared with those found in natural or computer-synthesized speech (e.g., fundamental frequency and simultaneity of harmonic onset). In each of the experiments, the TVS base stimuli were amplitude modulated to determine whether this modulation would lead to appropriate grouping of the three tones as reflected by sentence intelligibility. Experiment 1 demonstrated that amplitude comodulation at 100 Hz did improve the intelligibility of TVS sentences. Experiment 2 showed that the component tones of a TVS sentence must be comodulated (as opposed to independently modulated) for improvements in intelligibility to be found. Experiment 3 showed that the comodulation rates that led to intelligibility improvements were consistent with the effective rates found in experiments that examined the grouping of complex nonspeech sounds by common temporal envelopes (e.g., comodulation masking release; Hall, Haggard, & Fernandes, 1984). The results of these experiments support the claim that certain basic temporal-envelope processing capabilities of the human auditory system contribute to the perception of fluent speech.

Endobronchial closure of a postpneumonectomy bronchopleural fistula.

Successful permanent endobronchial closure of a serious postpneumonectomy bronchopleural fistula is reported in a patient with a delayed diagnosis of Mycobacterium fortuitum-cheloni infection. Increasing experience, improved plugging agents, and a review of the literature suggest that in selected patients, this procedure can avoid complex repeat operations and reverse life-threatening situations. Although atypical mycobacterial infections occur with infrequency, they are difficult to treat and may lead, as in this patient, to a misdiagnosis. Operations on granulomatous tissues are prone to heal poorly, thus inviting tissue breakdown and chronic fistulas.