Is Histologic Thrombus Composition in Acute Stroke Linked to Stroke Etiology or to Interventional Parameters?

BACKGROUND AND PURPOSE

Detailed insight into the composition of thrombi retrieved from patients with ischemic stroke by mechanical thrombectomy might improve pathophysiologic understanding and therapy. Thus, this study searched for links between histologic thrombus composition and stroke subtypes and mechanical thrombectomy results.

MATERIALS AND METHODS

Thrombi from 85 patients who had undergone mechanical thrombectomy for acute ischemic stroke between December 2016 and March 2018 were studied retrospectively. Thrombi were examined histologically. Preinterventional imaging features, stroke subtypes, and interventional parameters were re-analyzed. Statistical analysis was performed with the Kruskal-Wallis test, Mann-Whitney U test, or Spearman correlation as appropriate.

RESULTS

Cardioembolic thrombi had a higher percentage of macrophages and a tendency toward more platelets than thrombi of large-artery atherosclerotic stenosis (P = .021 and .003) or the embolic stroke of undetermined source (P = .037 and .099) subtype. Thrombi prone to fragmentation required the combined use of contact aspiration and stent retrieval (P = .021) and were associated with an increased number of retrieving maneuvers (P = .001), longer procedural times (P = .001), and a higher lymphocyte content (P = .035).

CONCLUSIONS

We interpreted the higher macrophage and platelet content in cardioembolic thrombi compared with large-artery atherosclerotic stenosis or embolic stroke of undetermined source thrombi as an indication that the latter type might be derived from an atherosclerotic plaque rather than from an undetermined cardiac source. The extent of thrombus fragmentation was associated with a more challenging mechanical thrombectomy and a higher lymphocyte content of the thrombi. Thus, thrombus fragmentation not only might be caused by the recanalization procedure but also might be a feature of a lymphocyte-rich, difficult-to-retrieve subgroup of thrombi.

Detection of early infarction signs with machine learning-based diagnosis by means of the Alberta Stroke Program Early CT score (ASPECTS) in the clinical routine

PURPOSE

New software solutions emerged to support radiologists in image interpretation in acute ischemic stroke. This study aimed to validate the performance of computer-aided assessment of the Alberta Stroke Program Early CT score (ASPECTS) for detecting signs of early infarction.

METHODS

ASPECT scores were assessed in 119 CT scans of patients with acute middle cerebral artery ischemia. Patient collective was differentiated according to (I) normal brain, (II) leukoencephalopathic changes, (III) infarcts, and (IV) atypical parenchymal defects (multiple sclerosis, etc.). ASPECTS assessments were automatically provided by the software package e-ASPECTS (Brainomix®, UK) (A). Subsequently, three neuroradiologists (B), (C), and (D) examined independently 2380 brain regions. Interrater comparison was performed with the definite infarct core as reference standard after best medical care (thrombolysis and/or thrombectomy).

RESULTS

Interrater comparison revealed higher correlation coefficient of (B) 0.71, (C) 0.76, and of (D) 0.80 with definite infarct core compared to (A) 0.59 for ASPECTS assessment in the acute ischemic stroke setting. While (B), (C), and (D) showed a significant correlation for individual patient groups (I), (II), (III), and (IV), except for (D) (II), (A) was not significant in patient groups with pre-existing changes (II), (III), and (IV). The following sensitivities, specificities, PPV, NPV, and accuracies given in percent were achieved: (A) 83, 57, 55, 82, and 67; (B) 74, 76, 69, 83, and 77; (C) 80.8, 85.2, 76, 84, and 80; (D) 63, 90.7, 82, 79, and 80, respectively.

CONCLUSION

For ASPECTS assessment, the examined software may provide valid data in case of normal brain. It may enhance the work of neuroradiologists in clinical decision making. A final human check for plausibility is needed, particularly in patient groups with pre-existing cerebral changes.

Outcomes of Pediatric Kidney Transplantation in Recipients of a Previous Non-Renal Solid Organ Transplant

Children who receive a non-renal solid organ transplant may develop secondary renal failure requiring kidney transplantation. We investigated outcomes of 165 pediatric kidney transplant recipients who previously received a heart, lung, or liver transplant using data from 1988 to 2012 reported to the United Network for Organ Sharing. Patient and allograft survival were compared with 330 matched primary kidney transplant (PKT) recipients. Kidney transplantation after solid organ transplant (KASOT) recipients experienced similar allograft survival: 5- and 10-year graft survival was 78% and 60% in KASOT recipients, compared to 80% and 61% in PKT recipients (p = 0.69). However, KASOT recipients demonstrated worse 10-year patient survival (75% KASOT vs. 97% PKT, p < 0.001). Competing risks analysis indicated that KASOT recipients more often experienced graft loss due to patient death (p < 0.001), whereas allograft failure per se was more common in PKT recipients (p = 0.01). To study more recent outcomes, kidney transplants performed from 2006 to 2012 were separately investigated. Since 2006, KASOT and PKT recipients had similar 5-year graft survival (82% KASOT vs. 83% PKT, p = 0.48), although 5-year patient survival of KASOT recipients remained inferior (90% KASOT vs. 98% PKT, p < 0.001). We conclude that despite decreased patient survival, kidney allograft outcomes in pediatric KASOT recipients are comparable to those of PKT recipients.

Evaluation of a low-carbohydrate diet-based preparation protocol without fasting for cardiac PET/MR imaging

OBJECTIVE

Assessment of increased glucose uptake in inflammatory or malignant myocardial disease using PET/MRI relies on uptake suppression in normal myocardium. We evaluated the efficacy of a ≥24 hours high-fat, low-carbohydrate, and protein-permitted diet (HFLCPP) in combination with unfractionated heparin for suppression of "physiologic" myocardial glucose uptake.

METHODS

PET/MRI was successfully performed in 89 patients. HFLCPP was started ≥24 hours prior to PET/MRI. All patients received i.v. injection of unfractionated heparin (50 IU·kg-1) 15 minutes prior to FDG administration. Left ventricular FDG uptake was visually evaluated by two readers. Diffuse myocardial uptake exceeding liver uptake, isolated uptake in the lateral wall, or diffuse uptake in the entire circumference of the heart base were defined as failed suppression. Homogeneous myocardial uptake below liver uptake with/without focal uptake was defined as successful suppression.

RESULTS

Success rate was 84%. Suppression was unsuccessful in 14 patients. No significant influence of gender (P = .40) or age (P = .21) was found. However, insufficient suppression was more common in patients younger than 45 years (20% vs 7%). PET/MR imaging completion rate was >97%.

CONCLUSION

A HFLCPP diet in combination with unfractionated heparin was successfully implemented for cardiac PET/MRI and resulted in a sufficient suppression of myocardial FDG uptake in 84% of patients.

Interferon Gamma ELISPOT Testing as a Risk-Stratifying Biomarker for Kidney Transplant Injury: Results From the CTOT-01 Multicenter Study

Previous studies suggest that quantifying donor-reactive memory T cells prior to kidney transplantation by interferon gamma enzyme-linked immunosorbent spot assay (IFNγELISPOT) can assist in assessing risk of posttransplant allograft injury. Herein, we report an analysis of IFNγELISPOT results from the multicenter, Clinical Trials in Organ Transplantation-01 observational study of primary kidney transplant recipients treated with heterogeneous immunosuppression. Within the subset of 176 subjects with available IFNγELISPOT results, pretransplant IFNγELISPOT positivity surprisingly did not correlate with either the incidence of acute rejection (AR) or estimated glomerular filtration rate (eGFR) at 6- or 12-month. These unanticipated results prompted us to examine potential effect modifiers, including the use of T cell-depleting, rabbit anti-thymocyte globulin (ATG). Within the no-ATG subset, IFNγELISPOT(neg) subjects had higher 6- and 12-month eGFRs than IFNγELISPOT(pos) subjects, independent of biopsy-proven AR, peak PRA, human leukocyte antigen mismatches, African-American race, donor source, and recipient age or gender. In contrast, IFNγELISPOT status did not correlate with posttransplant eGFR in subjects given ATG. Our data confirm an association between pretransplant IFNγELISPOT positivity and lower posttransplant eGFR, but only in patients who do not receive ATG induction. Controlled studies are needed to test the hypothesis that ATG induction is preferentially beneficial to transplant candidates with high frequencies of donor-reactive memory T cells.

PCR-based isolation of multigene families: lessons from the avian MHC class IIB

The amount of sequence data available today highly facilitates the access to genes from many gene families. Primers amplifying the desired genes over a range of species are readily obtained by aligning conserved gene regions, and laborious gene isolation procedures can often be replaced by quicker PCR-based approaches. However, in the case of multigene families, PCR-based approaches bear the often ignored risk of incomplete isolation of family members. This problem is most prominent in gene families with highly variable and thus unpredictable number of gene copies among species, such as in the major histocompatibility complex (MHC). In this study, we (i) report new primers for the isolation of the MHC class IIB (MHCIIB) gene family in birds and (ii) share our experience with isolating MHCIIB genes from an unprecedented number of avian species from all over the avian phylogeny. We report important and usually underappreciated problems encountered during PCR-based multigene family isolation and provide a collection of measures to help significantly improving the chance of successfully isolating complete multigene families using PCR-based approaches.

Multicenter validation of urinary CXCL9 as a risk-stratifying biomarker for kidney transplant injury

Noninvasive biomarkers are needed to assess immune risk and ultimately guide therapeutic decision-making following kidney transplantation. A requisite step toward these goals is validation of markers that diagnose and/or predict relevant transplant endpoints. The Clinical Trials in Organ Transplantation-01 protocol is a multicenter observational study of biomarkers in 280 adult and pediatric first kidney transplant recipients. We compared and validated urinary mRNAs and proteins as biomarkers to diagnose biopsy-proven acute rejection (AR) and stratify patients into groups based on risk for developing AR or progressive renal dysfunction. Among markers tested for diagnosing AR, urinary CXCL9 mRNA (odds ratio [OR] 2.77, positive predictive value [PPV] 61.5%, negative predictive value [NPV] 83%) and CXCL9 protein (OR 3.40, PPV 67.6%, NPV 92%) were the most robust. Low urinary CXCL9 protein in 6-month posttransplant urines obtained from stable allograft recipients classified individuals least likely to develop future AR or a decrement in estimated glomerular filtration rate between 6 and 24 months (92.5-99.3% NPV). Our results support using urinary CXCL9 for clinical decision-making following kidney transplantation. In the context of acute dysfunction, low values can rule out infectious/immunological causes of injury. Absent urinary CXCL9 at 6 months posttransplant defines a subgroup at low risk for incipient immune injury.

Outcomes of steroid-avoidance protocols in pediatric kidney transplant recipients

Advances in immunosuppression have facilitated increased use of steroid-avoidance protocols in pediatric kidney transplantation. To evaluate such steroid avoidance, a retrospective cohort analysis of pediatric kidney transplant recipients between 2002 and 2009 in the United Network for Organ Sharing database was performed. Outcomes (acute rejection and graft loss) in steroid-based and steroid-avoidance protocols were assessed in 4627 children who received tacrolimus and mycophenolate immunosuppression and did not have multiorgan transplants. Compared to steroid-based protocols, steroid avoidance was associated with decreased risk of acute rejection at 6 months posttransplant (8.3% vs. 10.9%, p = 0.02) and improved 5-year graft survival (84% vs. 78%, p < 0.001). However, patients not receiving steroids experienced less delayed graft function (p = 0.01) and pretransplant dialysis, were less likely to be African-American and more frequently received a first transplant from a living donor (all p < 0.001). In multivariate analysis, steroid avoidance trended toward decreased acute rejection at 6 months, but this no longer reached statistical significance, and there was no association of steroid avoidance with graft loss. We conclude that, in clinical practice, steroid avoidance appears safe with regard to graft rejection and loss in pediatric kidney transplant recipients at lower immunologic risk.

Glomerular filtration rate following pediatric liver transplantation--the SPLIT experience

Impaired kidney function is a well-recognized complication following liver transplantation (LT). Studies of this complication in children have been limited by small numbers and insensitive outcome measures. Our aim was to define the prevalence of, and identify risk factors for, post-LT kidney dysfunction in a multicenter pediatric cohort using measured glomerular filtration rate (mGFR). We conducted a cross-sectional study of 397 patients enrolled in the Studies in Pediatric Liver Transplantation (SPLIT) registry, using mGFR < 90 mL/min/1.73 m(2) as the primary outcome measure. Median age at LT was 2.2 years. Primary diagnoses were biliary atresia (44.6%), fulminant liver failure (9.8%), metabolic liver disease (16.4%), chronic cholestatic liver disease (13.1%), cryptogenic cirrhosis (4.3%) and other (11.8%). At a mean of 5.2 years post-LT, 17.6% of patients had a mGFR < 90 mL/min/1.73 m(2) . In univariate analysis, factors associated with this outcome were transplant center, age at LT, primary diagnosis, calculated GFR (cGFR) at LT and 12 months post-LT, primary immunosuppression, early post-LT kidney complications, age at mGFR, height and weight Z-scores at 12 months post-LT. In multivariate analysis, independent variables associated with a mGFR <90 mL/min/1.73 m(2) were primary immunosuppression, age at LT, cGFR at LT and height Z-score at 12 months post-LT.

Cost-efficient screening for BK virus in pediatric kidney transplantation: a single-center experience and review of the literature

BKVNP is an increasingly recognized cause of graft dysfunction and loss in kidney transplant recipients. Protocols for BKV screening and for the diagnosis of BKVNP are still evolving. PCR-based BKV detection became available at our institution in 2007, when we began using it according to published guidelines. We subsequently reviewed our experience with urine and plasma BKV PCR testing in our pediatric kidney transplant recipient population. We found rates of viruria, viremia, and BKVNP that were similar to the published literature. We also conducted a cost analysis suggesting that urine PCR testing, as used by us, is not cost efficient in the detection of BKV. We conclude that plasma only-based PCR testing for BKV may be sufficient in most clinical settings.

Ethical considerations for participation of nondirected living donors in kidney exchange programs

Kidneys from nondirected donors (NDDs) have historically been allocated directly to the deceased donor wait list (DDWL). Recently, however, NDDs have participated in kidney exchange (KE) procedures, including KE 'chains', which have received considerable media attention. This increasing application of KE chains with NDD participation has occurred with limited ethical analysis and without ethical guidelines. This article aims to provide a rigorous ethical evaluation of NDDs and chain KEs. NDDs and bridge donors (BDs) (i.e. living donors who link KE procedures within KE chains) raise several ethical concerns including coercion, privacy, confidentiality, exploitation and commercialization. In addition, although NDD participation in KE procedures may increase transplant numbers, it may also reduce NDD kidney allocation to the DDWL, and disadvantage vulnerable populations, particularly O blood group candidates. Open KE chains (also termed 'never-ending' chains) result in a permanent diversion of NDD kidneys from the DDWL. The concept of limited KE chains is discussed as an ethically preferable means for protecting NDDs and BDs from coercion and minimizing 'backing out', whereas 'honor systems' are rejected because they are coercive and override autonomy. Recent occurrences of BDs backing out argue for adoption of ethically based protective measures for NDD participation in KE.

UGT genotype may contribute to adverse events following medication with mycophenolate mofetil in pediatric kidney transplant recipients

Leukopenia and diarrhea are the predominant adverse events associated with mycophenolate mofetil (MMF), leading to dose reduction or discontinuation in children. Polymorphisms of the drug's main metabolizing enzyme, uridine diphosphate-glucuronosyl transferase (UGT), confer alteration in drug exposure. We studied the incidence of these polymorphisms in pediatric kidney transplant recipients experiencing MMF-associated leukopenia and diarrhea. UGT genotypes of 16 affected children who recovered after MMF dose reduction or discontinuation were compared with those of 22 children who tolerated the drug at standard doses. DNA was extracted and sequenced using standard procedures to detect polymorphisms associated with increased (e.g., UGT1A9 -331T>C) or decreased drug exposure. All three patients who were homozygous for UGT1A9 -331T>C developed leukopenia, and heterozygotes also had significantly more toxicity (P = 0.04). A weaker association (P = 0.08) existed in UGT2B7 -900G>A carriers. Our data implicate UGT polymorphisms associated with altered drug exposure as potential predictors of MMF adverse events.

Current kidney allocation rules and their impact on a pediatric transplant center

In 2005, kidney allocation rules in the United States were updated to enhance access to kidneys from young adult deceased donors (DDs) for pediatric recipients. We studied how this rule change affected transplant activity at our pediatric center. We retrospectively compared kidney transplant activity at our center since the rule change (until December 31, 2007) to before the change (n = 36 each), focusing on those recipients directly affected by it, that is, younger than 18 years. There were no significant differences in recipients' age, gender or ethnicity before versus after the rule change. Percentages of preemptive transplants and retransplants were similar in both groups, as was the percentage of sensitized patients. There was a significant decrease in overall, but not DD, mean donor age. Mean wait time for DD kidneys decreased for pediatric recipients. Increases were found in percentage of DD transplants and in mean HLA mismatches after the rule change. Patient and short-term graft survival were not significantly different. These data suggest that the allocation rule change was not only followed by improvement in overall access to kidney transplantation for children, but also by decreases in living donor transplants and HLA matching. Larger studies are needed to evaluate the long-term impact of the change.

Interstitial nephritis, hepatic failure, and systemic eosinophilia after minocycline treatment

This report describes a 15-year-old white boy who presented with fever, back pain, a disseminated exanthematous rash, renal failure, and hepatopathy 3 weeks after the initiation of oral minocycline therapy for facial acne. Marked peripheral and urine eosinophilia were noted. A bone marrow aspiration showed more than 50% eosinophils without any evidence of malignancy, and a simultaneous kidney biopsy showed acute interstitial nephritis (AIN). The patient's symptoms and laboratory findings improved after high-dose steroid therapy was initiated, worsened when it was withheld, and improved again after it was reinitiated in view of the biopsy findings. The patient recovered completely, and steroids were tapered to discontinuation over 3 months. Over a year later, the patient's peripheral blood mononuclear cells (PBMCs) were cultured for 2 weeks in the presence or absence of minocycline ex vivo, and minocycline was found to induce the emergence of CD4(+) cells after 1 week in culture. In conclusion, this article shows for the first time several new aspects of minocycline-induced morbidity: renal and hepatic failure can occur together, and AIN and elevated blood eosinophil counts can be accompanied by marked bone marrow eosinophilia, suggesting a systemic allergic response as the underlying pathomechanism. Furthermore, the initial phase of such a response appears to involve CD4(+) T cells detectable ex vivo. Lastly, high-dose treatment with corticosteroids appears to be beneficial in this setting.

The meaning of the word "vertigo"

OBJECTIVE

To determine whether otologists see a need to further define the word "vertigo" and assess the variety of meanings that are meant in using the word.

METHODS

A questionnaire was mailed to 720 members of the American Otological Society (AOS) and American Neurotological Society (ANS) to assess the need for further definition and the current understanding of the meaning of "vertigo."

RESULTS

The response rate was 42%. Significant variability in the intended meaning of the word "vertigo" was found suggesting that the definition is inconsistent among experts. Three quarters of the respondents indicated that the word needs further definition. The word was most commonly used to indicate sensations that include spinning or turning only.

CONCLUSION

The definition of the term "vertigo" is inconsistent among otolaryngologists. Refinement of the definition is desirable for accurate history taking and should be limited to false illusions of circular motion.

STAT5 pathway: target of anti-CD4 antibody in attenuation of IL-2 receptor signaling

BACKGROUND

Anti-CD4 antibodies induce long-term graft survival by incompletely understood mechanisms, and CD4-ligation with HIV gp120-derivatives attenuates interleukin (IL)-2 receptor signaling. We examined the latter in the context of the CD4-modulating antibody 16H5.

MATERIALS AND METHODS

We performed immunoblots to assess the IL-2-induced phosphorylation of signal transducer and activator of transcription (STAT)5 and Akt in the presence or absence of 16H5. Furthermore, we documented the effects of 16H5 on the induction of STAT5, activating protein (AP)-1, and myc by IL-2 in DNA-binding assays. 3H-thymidine incorporation of the human lymphoid cell line CMO, which exhibits constitutive activation of the STAT5 pathway and IL2-independent growth, was also measured during 16H5 treatment.

RESULTS

In human T lymphocytes, 16H5 attenuated both the tyrosine phosphorylation of STAT5 by IL-2 and the IL-2-induced DNA-binding of this transcription factor. In contrast, 16H5 had no effect on the serine phosphorylation of Akt by IL-2 or on the IL-2-induced DNA-binding of myc. Signal transduction involving AP-1 was unaffected by 16H5 and IL-2. 16H5 also attenuated CMO cell proliferation.

CONCLUSIONS

16H5 targets the STAT5 signaling pathway to attenuate IL-2 receptor signal transduction in human T cells. This observation provides a molecular explanation for the immunomodulatory actions of anti-CD4 antibodies.

Daclizumab (Zenapax) inhibits early interleukin-2 receptor signal transduction events

Daclizumab, a humanized antibody against the interleukin-2 (IL-2) receptor (R) alpha-chain, is a promising new immunosuppressant in transplantation. As its exact mechanism of action has remained unclear, we examined its short-term effects on primary human T lymphocytes expressing the high-affinity IL-2R. Daclizumab exposure for 20 min neither affected T cell viability nor their surface expression of the IL-2R alpha-, beta-, or gamma-chains. However, after IL-2 stimulation (200 U/ml, 20 min), immunoblots of cell lysates demonstrated attenuation of the IL-2-induced tyrosine phosphorylation of 65-75 kDa proteins by Daclizumab, but not by isotype controls. Since this is the molecular weight of the IL-2R beta- and gamma-chains, which are both tyrosine-phosphorylated by IL-2, we next examined the effect of Daclizumab on their IL-2-induced tyrosine phosphorylation. In immunoblots of IL-2R beta- and gamma-chain-immunoprecipitates the tyrosine phosphorylation of both chains by IL-2, but not by IL-15, was attenuated in the presence of Daclizumab. Furthermore, co-immunoprecipitation experiments showed that Daclizumab inhibited the IL-2-induced association of these chains, a prerequisite for their mutual tyrosine phosphorylation. Lastly, we demonstrated that Daclizumab inhibits the receptor-downstream induction of the IL-2-activated DNA-binding protein STAT5 in gel shift assays. We conclude that Daclizumab directly and specifically interferes with IL-2 signaling at the receptor level by inhibiting the association and subsequent phosphorylation of the IL-2R beta- and gamma-chains induced by ligand binding. Under our experimental conditions, Daclizumab had no effects on cell viability, and it did not modulate the surface expression of the IL-2R alpha-, beta-, or gamma-chains.

Solitary hepatic abscess with associated glomerulonephritis in a neonate

A full-term neonate with a history of umbilical venous catheterization followed by coagulase-negative staphylococcal sepsis is presented. The infant developed a solitary hepatic abscess with saprophytic organisms. Her liver abscess resulted in acute glomerulonephritis characterized by hypertension, proteinuria, oliguria, and azotemia. Surgical drainage and antibiotic treatment of the abscess was associated with resolution of the glomerulonephritis. Glomerulonephritis due to solitary liver abscess in a neonate has not been reported previously. Acute onset of glomerulonephritis should prompt a search for occult sources of infection.

Evaluation and treatment of severe hyperacusis

A 52-year-old male was evaluated by the authors after initially reporting fullness in his left ear while traveling on an airplane. A unique feature of the patient's complaint was the development of severe bilateral hyperacusis (loudness discomfort levels of between 20-34 dB HL) in spite of the fact that the hearing loss was initially reported in the left ear. To achieve loudness comfort, the patient was initially fit with ER-25 musician earplugs that proved to be unsuccessful. The patient next purchased earplugs and earmuffs from a gun shop in order to obtain relief from the pain and discomfort caused by his exposure to everyday environmental sounds. This paper describes the use of hearing devices that proved to be effective in providing attenuation sufficient that the patient rarely needs to rely on earplugs and earmuffs for relief from his hyperacusis.

Prednisolone plus albuterol versus albuterol alone in mild to moderate bronchiolitis

To evaluate combination therapy of mild to moderate bronchiolitis with bronchiodilators and corticosteroids, we treated 51 young children with first-time wheezing and symptoms of respiratory tract infection with albuterol plus either prednisolone or placebo for 5 days. Disease severity was scored on days 0, 2, 3, and 6. On day 2, prednisolone resulted in significantly lower scores (2.7 +/- 1.4 vs. 4.0 +/- 1.5 in all patients evaluated, p < 0.05) than placebo, whereas there was no detectable difference on day 6, suggesting that addition of prednisolone to albuterol transiently accelerates recovery from bronchiolitis. The clinical significance of this effect needs to be evaluated in further studies.

Hemodiafiltration for vancomycin overdose in a neonate with end-stage renal failure

We describe continuous venovenous hemodiafiltration (CVVHD) with a high-flux membrane as a novel treatment modality for vancomycin overdose associated with renal insufficiency. CVVHD was used in a 6-day-old male with a solitary hypodysplastic kidney, suspected sepsis, and anuric renal failure who subsequently received an accidental tenfold overdose of vancomycin. We furthermore present evidence for the importance of countercurrent dialysis in addition to continuous hemofiltration for optimal vancomycin removal.

Efficacy of a recombinant fowl pox-based Newcastle disease virus vaccine candidate against velogenic and respiratory challenge

A fowl pox-based recombinant virus TROVAC-NDV (vFP96.5) was developed expressing the fusion and hemagglutinin-neuraminidase glycoproteins from a velogenic strain of Newcastle disease virus (NDV). Studies in specific-pathogen-free birds indicated that inoculation of a single dose of the recombinant led to the induction of significant levels of hemagglutination-inhibiting antibody that were maintained to 8 wk postinoculation. Further, the recombinant induced protective immunity against a combined intramuscular velogenic NDV challenge and respiratory NDV challenge. In commercial broiler chickens that were inoculated in the presence of maternally derived NDV immunity, the level of the NDV-specific humoral response was dampened, but significant levels of protection against both a lethal intramuscular NDV challenge and a fowl poxvirus challenge were obtained.

Four cases of acoustic neuromas with normal hearing

In 95 percent of the cases, patients with acoustic neuromas will have some magnitude of hearing loss in the affected ear. This paper reports on four patients who had acoustic neuromas and normal hearing. Results from the case history, audiometric evaluation, auditory brainstem response (ABR), electroneurography (ENOG), and vestibular evaluation are reported for each patient. For all patients, the presence of unilateral tinnitus was the most common complaint. Audiologically, elevated or absent acoustic reflex thresholds and abnormal ABR findings were the most powerful diagnostic tools.

Intersubject variability of real-ear sound pressure level: conventional and insert earphones

Measures of the sound pressure level (SPL) near the eardrum were determined at discrete frequencies between 500 and 4000 Hz on 50 ears using TDH-39P and ER-3A earphones with the attenuator of an audiometer fixed at 90 dB HL. Results revealed significant differences in the measured SPL between the two earphones at all test frequencies. Results also revealed large intersubject differences in the SPL measured near the eardrum for both earphones. The results of this study highlight the large intersubject variability associated with measuring the SPL at the eardrum and point out the difficulty in accurately predicting individual performance from averaged group data.

High-frequency thresholds: circumaural earphone versus insert earphone

Benefits of high-frequency audiometry in monitoring hearing sensitivity of patients administered ototoxic medications are well established. High-frequency thresholds have been reported to be variable, due in part to small differences in the placement of the earphone diaphragm over the opening of the ear canal. Reliability may be improved by using insert earphones (ER-2) when obtaining high-frequency thresholds. The purposes of this study were to determine high-frequency threshold test-retest reliability using Koss HV/1A+ and ER-2 earphones and to determine if significant differences are present between high-frequency thresholds obtained using these two earphones. Results obtained on 40 ears of 20 normal hearing adults revealed that differences between the test and retest thresholds for each earphone were not significant. Intrasubject threshold differences between the test and retest thresholds for each earphone were, for the most part, within +/- 10 dB at all test frequencies. Further, significantly greater intensity was required to measure threshold when using the ER-2 earphone when compared to the Koss HV/1A+ at all test frequencies.

High-frequency thresholds: sound suite versus hospital room

Benefits of high-frequency audiometry in monitoring hearing sensitivity of patients administered ototoxic medications are well established. Thresholds obtained within a sound suite have been proven reliable. It may, however, often be necessary for the audiologist to evaluate the patient at bedside. The primary purpose of this study was to determine if significant differences are present between high-frequency thresholds measured in a sound suite versus thresholds measured in a hospital room. In addition, the test-retest reliability of high-frequency thresholds was determined when measured in a hospital room. For 25 normal hearing subjects, results revealed that significant differences were not observed between thresholds measured in a sound suite versus those measured in a typical hospital room. In addition, differences between the initial and repeated thresholds obtained in the hospital room were not significant, and the differences were, for the most part, within +/- 10 dB at all test frequencies.

Reliability and intersubject variability of the real ear unaided response

Intratester test-retest reliability of the real ear unaided response (REUR) was determined on 49 ears using the Frye 6500 real ear analyzer. Results revealed mean differences of less than 1 dB for repeat measurements at seven test frequencies between 250 and 4000 Hz. The average peak resonant frequency of the repeated measure was within 16 Hz of the initial measure. In addition, the intersubject variability of the amplitude of REUR was quite large. A range of 7 dB was found at 250 to 500 Hz with the range expanding to 15 to 20 dB at 2000 to 4000 Hz. Also, the peak resonant frequency varied between 2100-4800 Hz. These results are discussed in terms of those dispensers who use the REUR to "custom" order hearing aids.

Intratester test-retest reliability of insertion gain measures

Intratester test-retest reliability of insertion gain was determined on 28 subjects using the Frye 6500 real-ear analyzer. Results revealed mean differences of less than 1 dB for repeat measurements at six test frequencies between 250 and 4000 Hz. Also, over 80% of the repeat measures were within +/- 3 dB of the first measure. The results of this study are compared with previous studies of intratester reliability of insertion gain measures.

Use-effectiveness and analysis of satisfaction levels with the Billings Ovulation Method: two-year pilot study

A 2-year study of 135 women using the Billings Ovulation Method as their method of family planning is reported. There were 1381 exposure cycles during the 1st year and 580 during the 2nd year. The total conception rates were 1.303 for the 1st year and 1.896 for the 2nd year. If one subtract the user failures from these rates, the biologic failure rates are 0.072 for the 1st year and 0.517 for the 2nd year. The continuation rate is 51.8%. An analysis of satisfaction levels is presented with a discussion of possible underlying emotional factors.