Myocardial Strain for the Differentiation of Myocardial Involvement in the Post-Acute Sequelae of COVID-19-A Multiparametric Cardiac MRI Study

Myocardial involvement was shown to be associated with an unfavorable prognosis in patients with COVID-19, which could lead to fatal outcomes as in myocardial injury-induced arrhythmias and sudden cardiac death. We hypothesized that magnetic resonance imaging (MRI) myocardial strain parameters are sensitive markers for identifying subclinical cardiac dysfunction associated with myocardial involvement in the post-acute sequelae of COVID-19 (PASC). This study evaluated 115 subjects, including 65 consecutive COVID-19 patients, using MRI for the assessment of either post-COVID-19 myocarditis or other cardiomyopathies. Subjects were categorized, based on the results of the MRI exams, as having either 'suspected' or 'excluded' myocarditis. A control group of 50 matched individuals was studied. Along with parameters of global cardiac function, the MRI images were analyzed for measurements of the myocardial T1, T2, extracellular volume (ECV), strain, and strain rate. Based on the MRI late gadolinium enhancement and T1/T2/ECV mappings, myocarditis was suspected in 7 out of 22 patients referred due to concern of myocarditis and in 9 out of 43 patients referred due to concern of cardiomyopathies. The myocardial global longitudinal, circumferential, and radial strains and strain rates in the suspected myocarditis group were significantly smaller than those in the excluded myocarditis group, which in turn were significantly smaller than those in the control group. The results showed significant correlations between the strain, strain rate, and global cardiac function parameters. In conclusion, this study emphasizes the value of multiparametric MRI for differentiating patients with myocardial involvement in the PASC based on changes in the myocardial contractility pattern and tissue structure.

Clinical utility of whole-genome DNA methylation profiling as a primary molecular diagnostic assay for central nervous system tumors-A prospective study and guidelines for clinical testing

Background

Central nervous system (CNS) cancer is the 10th leading cause of cancer-associated deaths for adults, but the leading cause in pediatric patients and young adults. The variety and complexity of histologic subtypes can lead to diagnostic errors. DNA methylation is an epigenetic modification that provides a tumor type-specific signature that can be used for diagnosis.

Methods

We performed a prospective study using DNA methylation analysis as a primary diagnostic method for 1921 brain tumors. All tumors received a pathology diagnosis and profiling by whole genome DNA methylation, followed by next-generation DNA and RNA sequencing. Results were stratified by concordance between DNA methylation and histopathology, establishing diagnostic utility.

Results

Of the 1602 cases with a World Health Organization histologic diagnosis, DNA methylation identified a diagnostic mismatch in 225 cases (14%), 78 cases (5%) did not classify with any class, and in an additional 110 (7%) cases DNA methylation confirmed the diagnosis and provided prognostic information. Of 319 cases carrying 195 different descriptive histologic diagnoses, DNA methylation provided a definitive diagnosis in 273 (86%) cases, separated them into 55 methylation classes, and changed the grading in 58 (18%) cases.

Conclusions

DNA methylation analysis is a robust method to diagnose primary CNS tumors, improving diagnostic accuracy, decreasing diagnostic errors and inconclusive diagnoses, and providing prognostic subclassification. This study provides a framework for inclusion of DNA methylation profiling as a primary molecular diagnostic test into professional guidelines for CNS tumors. The benefits include increased diagnostic accuracy, improved patient management, and refinements in clinical trial design.

Introduction of Mutant GNAQ into Endothelial Cells Induces a Vascular Malformation Phenotype with Therapeutic Response to Imatinib

Simple Summary

Mutations in GNAQ underlie vascular malformations, including Sturge-Weber disease. In order to develop novel therapies for lesions with mutant GNAQ, we introduced mutant GNAQ into MS1 endothelial cells. Mutant GNAQ conferred a novel phenotype of progressive vascular malformations in mice. Chromatin analysis revealed upregulation of C-Kit in the vascular endothelial cells, and we found C-Kit to be highly expressed in Sturge-Weber disease. Given that imatinib is an FDA approved multikinase inhibitor that blocks C-Kit, we evaluated it in our mouse model, and showed that imatinib had activity against these vascular malformations. Repurposing imatinib should be evaluated in clinical trials, including Sturge-Weber disease.

Abstract

GNAQ is mutated in vascular and melanocytic lesions, including vascular malformations and nevi. No in vivo model of GNAQ activation in endothelial cells has previously been described. We introduce mutant GNAQ into a murine endothelial cell line, MS1. The resultant transduced cells exhibit a novel phenotype in vivo, with extensive vasoformative endothelial cells forming aberrant lumens similar to those seen in vascular malformations. ATAC-seq analysis reveals activation of c-Kit in the novel vascular malformations. We demonstrate that c-Kit is expressed in authentic human Sturge–Weber vascular malformations, indicating a novel druggable target for Sturge–Weber syndrome. Since c-Kit is targeted by the FDA-approved drug imatinib, we tested the ability of imatinib on the phenotype of the vascular malformations in vivo. Imatinib treated vascular malformations are significantly smaller and have decreased supporting stromal cells surrounding the lumen. Imatinib may be useful in the treatment of human vascular malformations that express c-Kit, including Sturge–Weber syndrome.

Multifocal congenital hemangioma: Expanding the pathogenesis of "neonatal hemangiomatosis"

Congenital hemangiomas are benign vascular tumors, categorized by their postnatal behavior as rapidly involuting, non-involuting, or partially involuting. They are typically solitary, with a predilection for the head or limbs near a joint. We present two infants with small, multifocal congenital nonprogressive hemangiomas of the skin, one associated with hepatic and intracranial lesions, and another with an in utero intracranial hemorrhage and hydrocephalus. These cases further extend the differential diagnosis of congenital multifocal vascular lesions or "hemangiomatosis."

Discovery of common chemical exposures across three continents using silicone wristbands

To assess differences and trends in personal chemical exposure, volunteers from 14 communities in Africa (Senegal, South Africa), North America (United States (U.S.)) and South America (Peru) wore 262 silicone wristbands. We analysed wristband extracts for 1530 unique chemicals, resulting in 400 860 chemical data points. The number of chemical detections ranged from 4 to 43 per wristband, with 191 different chemicals detected, and 1339 chemicals were not detected in any wristband. No two wristbands had identical chemical detections. We detected 13 potential endocrine disrupting chemicals in over 50% of all wristbands and found 36 chemicals in common between chemicals detected in three geographical wristband groups (Africa, North America and South America). U.S. children (less than or equal to 11 years) had the highest percentage of flame retardant detections compared with all other participants. Wristbands worn in Texas post-Hurricane Harvey had the highest mean number of chemical detections (28) compared with other study locations (10-25). Consumer product-related chemicals and phthalates were a high percentage of chemical detections across all study locations (36-53% and 18-42%, respectively). Chemical exposures varied among individuals; however, many individuals were exposed to similar chemical mixtures. Our exploratory investigation uncovered personal chemical exposure trends that can help prioritize certain mixtures and chemical classes for future studies.

A Multidisciplinary Consensus for Clinical Care and Research Needs for Sturge-Weber Syndrome

BACKGROUND

Sturge-Weber syndrome is a neurocutaneous disorder associated with port-wine birthmark, leptomeningeal capillary malformations, and glaucoma. It is associated with an unpredictable clinical course. Because of its rarity and complexity, many physicians are unaware of the disease and its complications. A major focus moving ahead will be to turn knowledge gaps and unmet needs into new research directions.

METHODS

On October 1-3, 2017, the Sturge-Weber Foundation assembled clinicians from the Clinical Care Network with patients from the Patient Engagement Network of the Sturge-Weber Foundation to identify our current state of knowledge, knowledge gaps, and unmet needs.

RESULTS

One clear unmet need is a need for consensus guidelines on care and surveillance. It was strongly recommended that patients be followed by multidisciplinary clinical teams with life-long follow-up for children and adults to monitor disease progression in the skin, eye, and brain. Standardized neuroimaging modalities at specified time points are needed together with a stronger clinicopathologic understanding. Uniform tissue banking and clinical data acquisition strategies are needed with cross-center, longitudinal studies that will set the stage for new clinical trials. A better understanding of the pathogenic roles of cerebral calcifications and stroke-like symptoms is a clear unmet need with potentially devastating consequences.

CONCLUSIONS

Biomarkers capable of predicting disease progression will be needed to advance new therapeutic strategies. Importantly, how to deal with the emotional and psychological effects of Sturge-Weber syndrome and its impact on quality of life is a clear unmet need.

Somatic second hit mutation of RASA1 in vascular endothelial cells in capillary malformation-arteriovenous malformation

Capillary malformation-arteriovenous malformation (CM-AVM) is an autosomal dominant vascular disorder that is associated with inherited inactivating mutations of the RASA1 gene in the majority of cases. Characteristically, patients exhibit one or more focal cutaneous CM that may occur alone or together with AVM, arteriovenous fistulas or lymphatic vessel abnormalities. The focal nature and varying presentation of lesions has led to the hypothesis that somatic "second hit" inactivating mutations of RASA1 are necessary for disease development. In this study, we examined CM from four different CM-AVM patients for the presence of somatically acquired RASA1 mutations. All four patients were shown to possess inactivating heterozygous germline RASA1 mutations. In one of the patients, a somatic inactivating RASA1 mutation (c.1534C > T, p.Arg512*) was additionally identified in CM lesion tissue. The somatic RASA1 mutation was detected within endothelial cells specifically and was in trans with the germline RASA1 mutation. Together with the germline RASA1 mutation (c.2125C > T, p.Arg709*) in the same patient, the endothelial cell somatic RASA1 mutation likely contributed to lesion development. These studies provide the first clear evidence of the second hit model of CM-AVM pathogenesis.

Abstract 327: Blood Vessels Need Ras Signaling to Maintain the Structure Integrity

The localization of prenylated Ras at the plasma membrane promotes activation of Ras by receptor tyrosine kinases, such as VEGF and FGF receptors. Although Ras has been implicated in angiogenesis, the exact regulatory mechanisms controlling Ras translocation and activation are currently unclear because little is known regarding molecules that control Ras translocation. Nogo-B receptor (NgBR) was identified as a receptor specific for Nogo-B, a cell surface ligand involved in blood vessel remodeling. Our recent study demonstrated that NgBR has a conserved hydrophobic pocket that promotes the membrane accumulation of Ras by directly binding prenylated Ras at the plasma membrane. As we expected, NgBR knockdown in endothelial cells diminishes the membrane localization of Ras and consequently abolishes VEGF/FGF-stimulated activation of Ras and Ras-mediated signalings such as phosphorylation of Akt and ERK. Therefore, NgBR knockout mouse is a unique animal model for examining the effects of Ras plasma membrane localization and Ras signaling on the morphogenesis of endothelial cells. Genetic deletion of NgBR in endothelial cells resulted in embryonic lethality and dilated cerebral blood vessels with fewer pericytes, which resembles the vascular lesion happened in cerebral cavernous malformation (CCM). CCM is characterized by an abnormal cluster of enlarged blood vessels in the brain and spinal cord and caused by dysfunction of three CCM genes (CCM1/2/3), which are required for maintaining endothelial cell (EC) junctions and pericyte recruitment. Our studies showed that NgBR transcript levels decrease in human CCM lesion, and NgBR endothelial specific knockout in mice results in decreased transcription of CCM1/2 in the yolk sac. Additional support for NgBR-CCM1/2 connections comes from studies using cultured human brain microvascular ECs, where loss of NgBR expression also decreases CCM1/2 transcription via NgBR-mediated Ras pathway, which is required for the expression of key transcription factors that are involved in regulating transcription of CCM1/2 genes. Our findings suggest that NgBR-Ras signaling pathway regulates CCM1/2 expression, and that disrupting this signaling pathway results in cerebrovascular malformation.

Leveraging a Sturge-Weber Gene Discovery: An Agenda for Future Research

Sturge-Weber syndrome (SWS) is a vascular neurocutaneous disorder that results from a somatic mosaic mutation in GNAQ, which is also responsible for isolated port-wine birthmarks. Infants with SWS are born with a cutaneous capillary malformation (port-wine birthmark) of the forehead or upper eyelid which can signal an increased risk of brain and/or eye involvement prior to the onset of specific symptoms. This symptom-free interval represents a time when a targeted intervention could help to minimize the neurological and ophthalmologic manifestations of the disorder. This paper summarizes a 2015 SWS workshop in Bethesda, Maryland that was sponsored by the National Institutes of Health. Meeting attendees included a diverse group of clinical and translational researchers with a goal of establishing research priorities for the next few years. The initial portion of the meeting included a thorough review of the recent genetic discovery and what is known of the pathogenesis of SWS. Breakout sessions related to neurology, dermatology, and ophthalmology aimed to establish SWS research priorities in each field. Key priorities for future development include the need for clinical consensus guidelines, further work to develop a clinical trial network, improvement of tissue banking for research purposes, and the need for multiple animal and cell culture models of SWS.

Genomics in clinical practice: lessons from the front lines

The price of whole-genome and -exome sequencing has fallen to the point where these methods can be applied to clinical medicine. Here, we outline the lessons we have learned in converting a sequencing laboratory designed for research into a fully functional clinical program.

Expression of NgBR is highly associated with estrogen receptor alpha and survivin in breast cancer

NgBR is a type I receptor with a single transmembrane domain and was identified as a specific receptor for Nogo-B. Our recent findings demonstrated that NgBR binds farnesylated Ras and recruits Ras to the plasma membrane, which is a critical step required for the activation of Ras signaling in human breast cancer cells and tumorigenesis. Here, we first use immunohistochemistry and real-time PCR approaches to examine the expression patterns of Nogo-B and NgBR in both normal and breast tumor tissues. Then, we examine the relationship between NgBR expression and molecular subtypes of breast cancer, and the roles of NgBR in estrogen-dependent survivin signaling pathway. Results showed that NgBR and Nogo-B protein were detected in both normal and breast tumor tissues. However, the expression of Nogo-B and NgBR in breast tumor tissue was much stronger than in normal breast tissue. The statistical analysis demonstrated that NgBR is highly associated with ER-positive/HER2-negative breast cancer. We also found that the expression of NgBR has a strong correlation with the expression of survivin, which is a well-known apoptosis inhibitor. The correlation between NgBR and survivin gene expression was further confirmed by real-time PCR. In vitro results also demonstrated that estradiol induces the expression of survivin in ER-positive T47D breast tumor cells but not in ER-negative MDA-MB-468 breast tumor cells. NgBR knockdown with siRNA abolishes estradiol-induced survivin expression in ER-positive T47D cells but not in ER-negative MDA-MB-468 cells. In addition, estradiol increases the expression of survivin and cell growth in ER-positive MCF-7 and T47D cells whereas knockdown of NgBR with siRNA reduces estradiol-induced survivin expression and cell growth. In summary, these results indicate that NgBR is a new molecular marker for breast cancer. The data suggest that the expression of NgBR may be essential in promoting ER-positive tumor cell proliferation via survivin induction in breast cancer.

C560Rβ3 caused platelet integrin αII b β3 to bind fibrinogen continuously, but resulted in a severe bleeding syndrome and increased murine mortality

BACKGROUND AND OBJECTIVES

β(3)-Deficient megakaryocytes were modified by human β(3)-lentivirus transduction and transplantation to express sufficient levels of a C560Rβ(3) amino acid substitution, for investigation of how an activated αII b β(3) conformation affects platelets in vivo in mice.

PATIENT/METHODS

As in our previous report of an R560β(3) mutation in a patient with Glanzmann thrombasthenia, R560β(3) murine platelets spontaneously bound antibody that only recognizes activated αII b β3 bound to its ligand, fibrinogen.

RESULTS

With this murine model, we showed that αII b -R560β3 mutation-mediated continuous binding of fibrinogen occurred in the absence of P-selectin surface expression, indicating that the integrin was in an active conformation, although the platelets circulated in a quiescent manner. Remarkably, only 35% of R560β(3) 'mutant' mice survived for 6 months after transplantation, whereas 87% of C560β(3) 'wild-type' mice remained alive. Pathologic examination revealed that R560β(3) mice had enlarged spleens with extramedullary hematopoiesis and increased hemosiderin, indicating hemorrhage. R560β(3) megakaryocytes and platelets showed abnormal morphology and irregular granule distribution. Interestingly, R560β(3) washed platelets could aggregate upon simultaneous addition of fibrinogen and physiologic agonists, but aggregation failed when platelets were exposed to fibrinogen before activation in vitro and in vivo.

CONCLUSIONS

The results demonstrate that continuous occupancy of αIIb β3 with fibrinogen disrupts platelet structure and function, leading to hemorrhagic death consistent with Glanzmann thrombasthenia rather than a thrombotic state.

Evaluation of metalloprotease inhibitors on hypertension and diabetic nephropathy

This study examined the effects of two new selective metalloprotease (MMP) inhibitors, XL081 and XL784, on the development of renal injury in rat models of hypertension, Dahl salt-sensitive (Dahl S) and type 2 diabetic nephropathy (T2DN). Protein excretion rose from 20 to 120 mg/day in Dahl S rats fed a high-salt diet (8.0% NaCl) for 4 wk to induce hypertension. Chronic treatment with XL081 markedly reduced proteinuria and glomerulosclerosis, but it also attenuated the development of hypertension. To determine whether an MMP inhibitor could oppose the progression of renal damage in the absence of changes in blood pressure, Dahl S rats were fed a high-salt diet (4.0% NaCl) for 5 wks to induce renal injury and then were treated with the more potent and bioavailable MMP inhibitor XL784 either given alone or in combination with lisinopril and losartan. Treatment with XL784 or the ANG II blockers reduced proteinuria and glomerulosclerosis by ~30% and had no effect on blood pressure. Proteinuria fell from 150 to 30 mg/day in the rats receiving both XL784 and the ANG II blockers, and the degree of renal injury fell to levels seen in normotensive Dahl S rats maintained from birth on a low-salt diet. In other studies, albumin excretion rose from 125 to >200 mg/day over a 4-mo period in 12-mo-old uninephrectomized T2DN rats. In contrast, albumin excretion fell by >50% in T2DN rats treated with XL784, lisinopril, or combined therapy. XL784 reduced the degree of glomerulosclerosis in the T2DN rats to a greater extent than lisinopril, and combined therapy was more effective than either drug alone. These results indicate that chronic administration of a selective MMP inhibitor delays the progression, and may even reverse hypertension and diabetic nephropathy.

Expanding the phenotype of multifocal lymphangioendotheliomatosis with thrombocytopenia

Multifocal lymphangioendotheliomatosis with thrombocytopenia is characterized by vascular skin and gastrointestinal (GI) tract lesions, thrombocytopenia, and GI bleeding. The first patient had scattered red macules and subcutaneous nodules on the skin with involvement of the lungs, liver, omentum, and right kidney. At 10 months of age he continues to have severe GI bleeding. The second patient had innumerable vascular plaques on the skin plus muscle, bone, lung, liver, and brain involvement. She died from respiratory failure at 8 months of age due to brainstem involvement. Both patients required aggressive management of GI bleeding, but had quite different skin findings and long-term outcomes.

Physiological matrix metalloproteinase concentrations in serum during childhood and adolescence, using Luminex Multiplex technology

Matrix metalloproteinases are a family of zinc-dependent proteinases which are involved in the breakdown and remodeling of extracellular matrix. As children grow and adolescents reach pubescence, their bodies undergo changes that require age-related morphogenesis of the extracellular matrix, possibly requiring unique patterns of matrix metalloproteinase (MMP) expression during periods of rapid tissue growth (i.e., childhood) or accelerated tissue remodeling and expansion (i.e., adolescence). Therefore, we have characterized age-specific and gender-specific differences in circulating concentrations of MMPs (specifically MMP-1, -2, -3, -8 and -9) in 189 serum samples obtained from healthy subjects, aged 2-18 years. MMP concentrations were measured using Fluorokine MultiAnalyte Profiling kits and a Luminex Bioanalyzer, as well as by commercial ELISA. Serum levels of MMP-1, -2, -3, -8, and -9 in healthy pediatric subjects represent log-normal distributions. MMP-2 was significantly negatively correlated with age (r=-0.29; p<0.001), while MMP-3 was significantly positively correlated with age (r=0.38; p<0.001). Although plasma, not serum, is considered the appropriate blood sample for measurement of MMP-8 and -9, serum levels of MMP-8 and -9 were also found to be highly positively correlated with each other (r=0.76; p<0.01). MMP results obtained by Fluorokin MultiAnalyte Profiling methods correlated well with conventional ELISA methods and use of this technology provided several advantages over ELISA.

Expression of Wilms tumor 1 gene distinguishes vascular malformations from proliferative endothelial lesions

BACKGROUND

Vascular malformations and hemangiomas, which are endothelial lesions of childhood, may result in considerable morbidity because they can cause discomfort and functional impairment and have a negative affect on the patient's appearance. Although vascular malformations may initially appear very similar to hemangiomas, they have distinct clinical courses. Infantile hemangiomas progress through 3 stages: proliferative, involuting, and involuted. The proliferative phase is characterized by clinical growth. Once hemangiomas reach their maximum size, they begin to regress or involute. Histologically, this stage is characterized by endothelial apoptosis. Finally, the involuted stage of the hemangioma occurs when the original lesion is replaced by a connective tissue remnant. In contrast to hemangiomas, vascular malformations do not involute but continue to enlarge as the patient grows.

OBSERVATIONS

The biochemical differences between hemangiomas, which involute, and vascular malformations, which do not involute, are not well understood. We found that the transcription factor encoded by the Wilms tumor 1 (WT1) gene is expressed in the endothelium of hemangiomas but not in vascular malformations.

CONCLUSIONS

Defects in WT1 signaling may underlie the inability of malformation endothelial cells to undergo physiologic apoptosis and remodeling. The availability of WT1 staining in hospital laboratories may allow the clinician to distinguish hemangiomas from vascular malformations and thus to give appropriate therapy to the patient.

Barriers to public health management of a pertussis outbreak in Arkansas

BACKGROUND

During the 2001-2002 respiratory season, Arkansas experienced one of its worst pertussis outbreaks. This crisis occurred shortly after the September 11, 2001, terrorist attacks.

OBJECTIVE

To determine whether vulnerabilities in the public health infrastructure existed in the context of emerging infectious diseases or possible bioterrorist attacks.

DESIGN

Key personnel involved in the Arkansas pertussis outbreak were interviewed, and health department epidemiologic data were reviewed.

SETTING

Observations were made for the statewide private-public management of the epidemic.

PARTICIPANTS

Physicians, infectious disease specialists, epidemiologists, field nurses, health department staff, laboratory staff, and administrators.

MAIN OUTCOME MEASURES

Diagnosis capability; vaccine, prophylaxis, and treatment programs; and effectiveness of global outbreak management.

RESULTS

Diagnosis of pertussis was a major barrier to management of the outbreak. The nonspecific clinical diagnosis, unreliability of testing methods, excessive number of samples, unavailability of reagents, and inadequate transport system, laboratory personnel, and equipment all impeded effective diagnosis. Vaccine shortage was not believed to contribute to the extent of the outbreak. Prophylaxis was problematic because of feared adverse effects of drugs and uncertainty about the efficacy of new drugs, but compliance was found to be good. From a public health perspective, isolation procedures, school absence policies, and health department referrals to private physicians all contributed to confusion. Problems with communications, staffing, and public cooperation were identified. Despite these barriers, the epidemic was well tolerated, with no known mortality and limited morbidity.

CONCLUSIONS

Despite many identified barriers to effective public health management, Arkansas tolerated its worst epidemic of pertussis in many years. However, were the state to experience an outbreak of a more pathogenic agent, introduced either naturally or of bioterrorist origin, these vulnerabilities could become critical. Natural outbreaks serve as excellent experiences on which to recognize and correct barriers to public health management.

Specific Computerized Attention Training in Stroke and Traumatic Brain-Injured Patients

Abstract: In a multicenter European approach, the efficacy of the AIXTENT computerized training programs for intensity aspects (alertness and vigilance) and selectivity aspects (selective and divided attention) of attention was studied in 33 patients with brain damage of vascular and traumatic etiology. Each patient received training in one of two most impaired of the four attention domains. Control tests were performed by means of a standardized computerized attention test battery (TAP) comprising tests for the four attention functions. Assessment was carried out at the beginning and at the end of a four week baseline period and after the training period of 14 one-hour sessions. At the end of the baseline phase, there was only slight but significant improvement for the most complex attention function, divided attention (number of omissions). After the training, there were significant specific training effects for both intensity aspects (alertness and vigilance) and also for the number of omissions in the divided attention task. The application of inferential single case procedures revealed a high number of significant improvements in individual cases after specific training of alertness and vigilance problems. On the other hand, a non specific training addressing selectivity aspects of attention lead either to improvement or deterioration of alertness and vigilance performance. The results corroborate the findings of former studies with the same training instrument but in patients with different lesion etiologies.

Comparison of manual and automated leukocyte counts for determination of the absolute neutrophil count: application to a pediatric oncology clinic

BACKGROUND

Determination of the absolute neutrophil count (ANC) is a critical test prior to initiation of chemotherapy and is a standard component of cancer therapy protocols. Automated determination of this parameter potentially shortens the turnaround time necessary between specimen phlebotomy and chemotherapy infusion in an outpatient setting. However, there are certain factors that can lead to spuriously elevated or lowered ANCs, possibly leading to inappropriate dosage. We therefore compared ANC results in a series of samples in which both automated and manual results were available.

PROCEDURE

Sets of 111 specimens, tested over a 1-month period, had matched automated and manual ANC results available for initial retrospective analysis. An additional set of 35 specimens with ANCs of <1.5 x 10(9)/L were subsequently analyzed in a similar fashion. Automated ANC results were obtained with a Cell-Dyn 3500 (Abbott Diagnostics, Santa Clara, CA, USA) automated hematology analyzer, and manual ANC results were obtained using 100 cell differentials performed by 1 of 13 medical technologists. Results were tabulated and analyzed using standard linear regression and scatter plot analyses.

RESULTS

Of the initial 111 specimens, automated ANC values ranged from 0.16-14.2 x 10(9)/L (median=2.6 x 10(9)/L), as compared with 0.24-13.9 x 10(9)/L (median 3.0 x 10(9)/L) for manual ANC values (R(2) = 0.99; SE=0.49). Differences between the ANC values ranged from -55 to +33% (SD=14%) of the manual value. Of the second set of 35 specimens, regression analysis yielded an R(2) value of 0.92, with a SE of 0.11. Both data sets yielded acceptable degrees of variation on scatter plot analyses.

CONCLUSIONS

Automated ANC values appear adequate for determining suitability for chemotherapy and lessen the turnaround time between specimen phlebotomy and result verification.

Immunogenic and antigenic dominance of a nonneutralizing epitope over a highly conserved neutralizing epitope in the gp41 envelope glycoprotein of human immunodeficiency virus type 1: its deletion leads to a strong neutralizing response

The Kennedy peptide, (731)PRGPDRPEGIEEEGGERDRDRS(752), from the cytoplasmic domain of the gp41 transmembrane envelope glycoprotein of HIV-1 contains a conformationally dependent neutralizing epitope (ERDRD) and a linear nonneutralizing epitope (IEEE). No recognized murine T cell epitope is present. The peptide usually stimulates virus-specific antibody, but this is not always neutralizing. Here we show that IEEE (or possibly IEEE plus adjacent sequence) is immunogenically and antigenically dominant over the ERDRD neutralizing epitope. Thus rabbits immunized in a variety of routes, doses, and adjuvants with a chimeric cowpea mosaic virus (CPMV) expressing the Kennedy peptide on its surface (CPMV-HIV/1) synthesized IEEE-specific serum antibody but no ERDRD-specific or HIV-1-neutralizing antibody. To test if this resulted from immunodominance or from a hole in the antibody repertoire, we immunized rabbits with chimera CPMV-HIV/29, which expresses the GERDRDR part of the Kennedy sequence. This chimera readily stimulated ERDRD-specific, neutralizing antibody. In mice the situation was less extreme, but individual animals with low neutralizing titers had a high ratio of IEEE-specific:ERDRD-specific antibody. Data are consistent with immunodominance of IEEE over ERDRD in the Kennedy peptide. IEEE-specific antibody was also antigenically dominant and prevented ERDRD-specific antibody from binding to its epitope and from neutralizing HIV-1. It may be that HIV-1 has evolved a nonneutralizing immunodominant epitope that allows it to possess a neutralizing epitope without suffering the consequences, and this idea is supported by the covariance of both epitope sequences. To our knowledge this is the first example of a defined sequence that controls the activity of an adjacent epitope.

Evidence of residual disease in ossicles of patients undergoing cholesteatoma removal

For the past several years there has been much debate regarding the advisability of reusing the incus for ossicular reconstruction in cases involving cholesteatoma. There appears to be some evidence that microscopic foci of cholesteatoma in the incus could lead to reimplantation of the cholesteatoma should the incus be used in the reconstruction phase. In an effort to elucidate the incidence of microscopic residual cholesteatoma, the incudes of patients with cholesteatoma were examined both grossly in the operating room and microscopically in the laboratory for erosion and residual cholesteatoma. Our examination showed that a number of specimens apparently free of cholesteatoma after macroscopic examination had microscopic evidence of cholesteatoma. Likewise, microscopic examination of an incus that appeared to be free of residual cholesteatoma revealed epithelial cells deeply invading the bone. Macroscopic examination consistently underestimated the amount of erosion that was clearly evident upon histologic examination. In light of these findings, gross examination of the incus after removal of cholesteatoma is not reliably predictive of invasive microscopic disease. Reusing the ossicles in this situation creates the potential of reimplanting the disease.

An informal assessment of nutritional status in acute stroke for use in an international multicentre trial of feeding regimens

Patients with acute stroke may become malnourished because of feeding difficulties, so dietary supplementation may improve outcome. We investigated the validity and reliability of an 'eyeball' assessment of nutritional status for use in an international trial of different feeding following acute stroke. One hundred and one inpatients (mean age 75 years), of whom 40 had suffered an acute stroke, were independently observed by two medical students, a doctor and a nurse, and categorised as underweight, normal weight or overweight. Body mass index (BMI) was calculated using height and weight. Sensitivity of the informal assessment for correctly classifying the patient as underweight (BMI < 20 kg/m2), normal (20-30 kg/m2) and overweight (BMI > 30 kg/m2) ranged from 64% to 100% and specificity from 71% to 100%. Interobserver agreement between different pairs of observers was moderate to good. An 'eyeball' assessment of nutritional status is valid and reliable enough for use in a multicentre trial of feeding regimens following acute stroke.

Clenbuterol: a substitute for anabolic steroids?

Clenbuterol is a recently popular drug used by athletes in many sports for its purported anabolic effects and reduction of subcutaneous fat. It is a beta-2 (beta 2) agonist prescribed overseas as a bronchodilator, but not approved for use in this country. It is on the banned substance list of the United States Olympic Committee. To avoid any erosion of confidence, physicians caring for athletes need accurate information regarding clenbuterol. Such information is unavailable within the routine medical environs. A review of the literature of animal husbandry reveals that this drug, when administered in doses far greater than those required for bronchodilation, does indeed increase the deposition rate of lean mass and retard adipose gain. There are no human studies available. Animal studies were conducted on laboratory and slaughter stock. No investigation into long-term cardiovascular side effects has been undertaken. The rate of extrapolation from animal studies to unsupervised human usage is alarming. If this category of drugs does preserve lean mass in humans, there are legitimate medical applications. Trials of efficacy and safety are needed.

Cyclic AMP-dependent protein kinase type I is involved in hypersensitivity of human breast cells to topoisomerase II inhibitors

Topoisomerase II (Topo II) is an essential enzyme that catalyzes the breakage of double-strand DNA and is the target of several effective anticancer drugs, including the epipodophyllotoxins. The regulatory subunits of the cyclic AMP-dependent protein kinase are differentially expressed in normal and cancer cells. The RIalpha subunit is overexpressed in cells transformed by transforming growth factor-alpha (TGF-alpha) or Ha-ras oncogene. It has been shown that murine cells transformed by Ha-ras become hypersensitive to Topo II-targeting anticancer drugs. In this report we have tested whether any correlation exists between the expression of RIalpha protein and cellular sensitivity of Topo II-targeting drugs. Normal human breast MCF-10A cells and their derivatives overexpressing TGF-alpha, Ha-ras, or the different protein kinase subunits were treated with either Topo II inhibitors, such as etoposide, teniposide, or amsacrine, or with drugs which act independently of Topo II, such as bleomycin. Here we show that MCF-10A TGF-alpha and MCF-10A Ha-ras cells overexpress the RIalpha protein and become hypersensitive to epypodophyllotoxins and amsacrine but not to bleomycin. Direct introduction of the RIalpha gene into MCF-10A induces hypersensitivity to Topo II inhibitor drugs. In contrast, the overexpression of the other protein kinase subunits, RIIbeta or Calpha, does not modify the drug sensitivity of MCF-10A cells. No differences in the mRNA/protein content or in the activity of Topo II were found between hypersensitive cells and parental MCF-10A cells, suggesting that RIalpha may influence drug sensitivity via modulation of events downstream of the Topo II-DNA cleavable complex.

Repair and misrepair of site-specific DNA double-strand breaks by human cell extracts

The rejoining by human cell extracts of a double-strand break induced by endonuclease treatment at one of several sites within a small DNA molecule was studied. Rejoining was found at each of 8 sites tested, but the rejoin efficiency varied with the nature of the break (e.g., breaks with cohesive ends were rejoined more efficiently than blunt-ended breaks). Extracts from primary and immortalized cell lines, as well as those from individuals with ataxia telangiectasia (A-T), showed the same pattern of relative rejoin efficiencies. However, mis-rejoining varied with the cell extract used, and was particularly elevated with two immortalized A-T cell lines. Mixing experiments showed that the mis-rejoining property of extracts could act in a semi-dominant fashion, depending on the individual efficiencies of the component extracts. The mis-rejoin mechanism involved deletion at sites of short direct repeats at various distances from the initial break site. A model of deletion formation (the strand-exposure and repair model) is restated to explain the sequence repeat dependence found, and is compared to models of homologous DNA recombination.

A mechanism for deletion formation in DNA by human cell extracts: the involvement of short sequence repeats

DNA molecules carrying a site-specific double-strand break were exposed to nuclear extracts from human cell lines. It was shown previously that breaks could be rejoined correctly by human extracts, but that a proportion of the rejoined molecules had suffered deletions and insertions. The 'mis-rejoined' proportion was higher with cell extracts from an individual with the disorder ataxia-telangiectasia than with normal cell extracts. We now show by sequence analysis that deletions in extract-treated molecules occur exclusively between short direct repeats (2-6 base pairs). A mis-rejoined molecule containing an insertion of 300 bp also had a repeat-based deletion at the same site. A number of different direct repeats are involved; however, some clustering of these occurs especially on the upstream side of the initial breakpoint. These data are most simply interpreted in terms of a model of deletion formation involving single-strand exposure and repair, perhaps with the action of other DNA-metabolising enzymes influencing the frequency with which some repeats are involved.

Sexual activity and condom use in high school students

OBJECTIVE

To determine the level of sexual experience and condom use among Year 9 high school students.

DESIGN

Self-administered questionnaire to all Year 9 students attending a personal development workshop.

SETTING

The study was carried out in two regional high schools in New South Wales, one in an urban area and the other in a rural area.

PARTICIPANTS

A total of 253 students in Year 9 at the two high schools; only two students declined to participate.

RESULTS

Seventy-one students (28.1%) had had intercourse at least once. There was no statistically significant difference between the percentage of male and female students or rural and urban students who had had intercourse. Thirty students (42.3%) always used condoms, 35.2% used them sometimes and the other sexually active students had never used them. The commonest reasons for non-use were unplanned sex, unavailability or no time.

CONCLUSIONS

The unpredictability of teenage sexual activity may mean that condoms are not available at the crucial time. Girls appear to have more difficulty in asking for condoms to be used, but the numbers are two small in this survey to draw definite conclusions. If both pregnancy and sexually transmissible diseases are to be prevented among adolescents, sex education must encourage condom use as the first method of contraception for this group and emphasise the need for consistent availability and use.

The rejoining of double-strand breaks in DNA by human cell extracts

A double-strand DNA break was introduced at a specific site within the lacZ gene of plasmid pUC18 using one of several restriction enzymes, and the plasmid exposed to nuclear extracts from human cell lines. Physical rejoining of DNA was monitored by Southern analysis after gel separation, and the fidelity of rejoining by expression of the lacZ gene after bacterial transformation with the treated plasmid. Breaks at the SalI and EcoRI sites were rejoined by extracts to form circular monomers, but the efficiency of rejoining was much higher at the SalI site. Measurement of rejoining at several adjacent sites having different types of termini, consistently showed a range of efficiencies with 5' 4-base greater than 3' 4-base overhangs and 4-base greater than 2-base greater than no overhang. Similar efficiencies were found for nuclear extracts from transformed cell lines, both from a 'normal' individual and an ataxia-telangiectasia (A-T) patient, and from a non-transformed normal cell culture. In contrast at some sites, especially those with a low rejoin efficiency, the fidelity of rejoining was very much lower for the A-T extracts than for normal cell extracts. Mis-rejoining was, however, unrelated to rejoin efficiency at other sites, suggesting that factors such as the exact sequence at the break site on the molecule may also influence the fidelity of rejoining.

Influence of human immunodeficiency virus antibody testing on sexual behaviour in a "high-risk" population from a "low-risk" city

A survey was undertaken of homosexual and bisexual men in Brisbane to establish whether knowledge of their human immunodeficiency virus (HIV)-antibody status had influenced any sexual behaviour that was likely to spread HIV type 1 (HIV-1). Of the 318 respondents, 123 respondents knew their HIV serological status, and 13 of these were HIV seropositive. Of the 195 respondents who previously had not been tested, 10 individuals proved to be HIV seropositive. Eighty-two per cent of subjects stated that they had reduced their sexual activity because of their awareness of the acquired immunodeficiency syndrome (AIDS); this reduction was equally common among those who had or had not previously had their HIV serological status checked. Anal intercourse was practised most frequently by those subjects who were HIV seropositive and were not aware of it; nevertheless, unprotected anal intercourse was common among subjects who knew their HIV serological status, including those who knew that they were HIV seropositive. Eighty-nine of 208 subjects who were practising anal intercourse had never used a condom. Usage of a condom was marginally more common among those subjects who previously had been tested for the presence of HIV antibodies (P = 0.06), and this was particularly so for those subjects who knew that they were HIV seropositive (P less than 0.01). Condom usage was no more common among those subjects who knew that they were HIV seronegative, when compared with those subjects who did not know their status. These data show that knowledge of a negative HIV-antibody test-result has no substantial association with safer sexual behaviour and suggest that whereas targeted information programmes have had some impact on behaviour in high-risk groups in Brisbane, by the end of July 1986, these programmes had not yet resulted in safer sexual practices by the majority of homosexual and bisexual men.

The analysis of multiple polymorphic loci on a single human chromosome to exclude linkage to inherited disease: cystic fibrosis and chromosome 4

Classical linkage programs analyze the segregation of two markers in informative families. When several markers are available for one human chromosome, pairwise analysis can exclude linkage between each marker and an inherited disease. The identification of restriction fragment length polymorphisms has made many new informative markers, assigned to chromosomes, available. We have adapted the multipoint linkage program MLINK developed by Lathrop et al. in order to exclude linkage between cystic fibrosis and several markers known to be on human chromosome 4. The exclusion obtained is greater than that for a pairwise analysis.

Inhibition of (Na,K)-ATPase by tetravalent vanadium

Vanadyl, the tetravalent state of vanadium and a divalent cation, VO2+, was a relatively powerful inhibitor of highly purified membrane-bound sodium and potassium ion transport adenosine triphosphatase. The sensitivity of the ATPase activity to vanadyl characteristically correlated positively with the specific activity of the enzyme preparation. Inhibition ranged from nearly complete inhibition at less than 5 microM vanadyl for some of the purest fractions (specific activity approximately 45 mumol/min/mg of protein) to no observable inhibition at 300 microM vanadyl in one crude preparation of the enzyme with a specific activity of 10 mumol/min/mg of protein. The level of free vanadyl was reduced by incubation with these membranes, but this reduction was not sufficient to account for the low sensitivity to vanadyl observed in crude preparations. A reduction in specific activity by partial inactivation of a sensitive preparation by treatment with FeCl3 and ascorbate reduced its sensitivity to vanadyl. Anionic ligands of the enzyme, vanadate or ATP, increased the rate of recovery from inhibition after chelation of free vanadyl. At pH 6.1, the inhibition was characteristically fully reversible (t1/2 approximately 10 min), whereas at pH 8.1 it was stable for hours. The degree and stability of enzyme inhibition by vanadyl increased for several hours during incubation of the vanadyl-enzyme mixture, and at pH 6.1 the properties of the inhibitor itself also changed with time. Preincubation of the ion at that pH for 5 h before addition of the enzyme produced a more stable inhibition. The time- and pH-dependent changes in the degree and stability of enzyme inhibition probably relate to the complex chemistry of the vanadyl ion in solution.

Protein-mediated exchange of synthetic phosphatidylcholines into synaptosomal membranes

A phosphatidylcholine (PC) exchange protein from bovine liver was used to exchange endogenous synaptosomal membrane PC's with PC's of defined fatty-acid composition from phospholipid vesicles. Up to 50% of the total synaptosomal PC could be exchanged during a 3 h incubation with PC's which were in the liquid-crystalline state at the temperature of incubation (dimyristoyl-, dioleoyl- and dielaidoyl-PC). The biphasic kinetics of the exchange of 14C-labeled 1-palmitoyl-2-oleoyl-PC into isolated synaptic plasma membrane vesicles indicated that the half-time for transbilayer equilibrium of PC in these membranes was about 10 h. Hence, the observed 50% exchange of total synaptosomal PC probably represented nearly complete exchange of PC in the outer face of the synaptosomal plasma membrane. This extensive exchange was accomplished without apparent loss of synaptosomal function, including membrane potential and high-affinity uptake of choline and gamma-aminobutyric acid. PC's in the gel state (dipalmitoyl- and distearoyl-PC) could not be exchanged extensively into the synaptosomal membranes. However, from within gel-state distearoyl-PC liposomes, a trace amount of fluid 1-palmitoyl-2-oleoyl-PC (Tm less than 10 degrees C) could be preferentially exchanged into the synaptosomes at 32 degrees C with little transfer of the saturated PC.