Systematic assessment of long-read RNA-seq methods for transcript identification and quantification

The Long-read RNA-Seq Genome Annotation Assessment Project (LRGASP) Consortium was formed to evaluate the effectiveness of long-read approaches for transcriptome analysis. The consortium generated over 427 million long-read sequences from cDNA and direct RNA datasets, encompassing human, mouse, and manatee species, using different protocols and sequencing platforms. These data were utilized by developers to address challenges in transcript isoform detection and quantification, as well as de novo transcript isoform identification. The study revealed that libraries with longer, more accurate sequences produce more accurate transcripts than those with increased read depth, whereas greater read depth improved quantification accuracy. In well-annotated genomes, tools based on reference sequences demonstrated the best performance. When aiming to detect rare and novel transcripts or when using reference-free approaches, incorporating additional orthogonal data and replicate samples are advised. This collaborative study offers a benchmark for current practices and provides direction for future method development in transcriptome analysis.

Clinical Outcomes of Conservative Treatment for Low-Risk Ductal Carcinoma in Situ: A Systematic Review and Pooled Analysis

AIMS

The current gold standard of treatment for ductal carcinoma in situ (DCIS) is surgical resection with or without adjuvant radiotherapy. However, the increased detection and radical treatment of DCIS did not result in a declined incidence of invasive breast cancers, leading to the debate if DCIS has been overtreated. While ongoing randomised controlled trials on active surveillance of DCIS are still in progress, this systematic review aims to evaluate the best evidence on conservative treatment for DCIS from the literature.

MATERIALS AND METHODS

This systematic review was conducted in line with the PRISMA statement. We included all relevant studies published up to June 2022 for analysis. The primary outcomes were overall survival and breast cancer-specific survival (BCSS) of conservative treatment for DCIS.

RESULTS

Three studies, with a total of 34 007 women with low-risk DCIS, were included in the analysis. Active and conservative treatments both resulted in excellent 10-year BCSS, with no statistically insignificant difference (98.6% versus 96.0%, 31 478 women). One study comparing 5-year BCSS of active and conservative treatments only in subjects aged over 80 years also reported [AQ1]an insignificant difference (98.2% versus 96.0%, 2529 women). One study measuring 5- and 10-year overall survival between the treatment groups also reported [AQ1]an insignificant difference (5-year: 96.2% versus 92.4%; 10-year: 85.6% versus 86.7%, 31 106 women).

CONCLUSION

BCSS between active and conservative treatment for women with low-risk DCIS is both excellent and comparable, suggesting that conservative treatment is a possible alternative without compromising survival.

A comparison framework and guideline of clustering methods for mass cytometry data

Background

With the expanding applications of mass cytometry in medical research, a wide variety of clustering methods, both semi-supervised and unsupervised, have been developed for data analysis. Selecting the optimal clustering method can accelerate the identification of meaningful cell populations.

Result

To address this issue, we compared three classes of performance measures, “precision” as external evaluation, “coherence” as internal evaluation, and stability, of nine methods based on six independent benchmark datasets. Seven unsupervised methods (Accense, Xshift, PhenoGraph, FlowSOM, flowMeans, DEPECHE, and kmeans) and two semi-supervised methods (Automated Cell-type Discovery and Classification and linear discriminant analysis (LDA)) are tested on six mass cytometry datasets. We compute and compare all defined performance measures against random subsampling, varying sample sizes, and the number of clusters for each method. LDA reproduces the manual labels most precisely but does not rank top in internal evaluation. PhenoGraph and FlowSOM perform better than other unsupervised tools in precision, coherence, and stability. PhenoGraph and Xshift are more robust when detecting refined sub-clusters, whereas DEPECHE and FlowSOM tend to group similar clusters into meta-clusters. The performances of PhenoGraph, Xshift, and flowMeans are impacted by increased sample size, but FlowSOM is relatively stable as sample size increases.

Conclusion

All the evaluations including precision, coherence, stability, and clustering resolution should be taken into synthetic consideration when choosing an appropriate tool for cytometry data analysis. Thus, we provide decision guidelines based on these characteristics for the general reader to more easily choose the most suitable clustering tools.

P4-01-04: Effects of CYP2D6 Phenotype and Drug Adherence on Tamoxifen Metabolite Levels

Background

Although the activity of cytochrome P450 2D6 (CYP2D6), the enzyme responsible for conversion of tamoxifen (TAM) to its most important active metabolite endoxifen, varies significantly with genotype. Routine genotype testing in patients on TAM has recently been discouraged. Conflicting results in publications regarding the prognostic utility of this test remain unexplained. Confounding factors could be lack of predicted correlation between CYP2D6 genotype and TAM active metabolites, or variability of patient compliance

Methods: Consecutive breast cancer patients on TAM were asked to enroll in a study to examine the relationship between CYP 2D6 phenotype, patient-reported treatment adherence, and TAM metabolites levels. Patients were genotyped for CYP2D6 polymorphisms using long-range PCR allele-specific amplification and single-nucleotide primer extension assay. From the genotypes, four phenotype groups were defined: Ultra rapid Metabolizer (UM), Extensive Metabolizer (EM), Intermediate Metabolizer (IM) and Poor Metabolizer (PM). Plasma was collected after at least 6 weeks of TAM (20 mg daily). The parent drug TAM, as well as 4-hydroxy N-desmethyl tamoxifen (endoxifen), 4 hydroxy tamoxifen (4OHtam) and N-desmethyl-tamoxifen (NDtam), were determined by Liquid Chromatography tandem mass-spectrometry (LC-MS/MS). Patients also completed a questionnaire about ethinicity, side effects, concurrent medications and tamoxifen adherence. Correlation between metabolite/TAM ratio and phenotype was tested by Spearman correlation test. Relationship between metabolite levels and adherence was tested by Wilcoxon rank sum test. Chi square test was used to compare proportions.

Results: Of the 100 patients enrolled there were 62 Caucasians, 25 Asians, 4 Africans and 6 Unknown. We found a strong correlation between ratio of endoxifen/TAM and phenotype (p <.0001) (Table 1) Over a 2 week period 68 never missed a TAM dose, 25 missed 1–2 times, 2 missed 3–5 times and 2 > 5times (2 missing data). In EM group we found significantly lower levels of TAM (p <.0001), NDtam (p=.008), 4OHtam (p=.003) in less adherent patients. A trend to decreased levels was also shown for endoxifen (p=.081). No associations were found between adherence or phenotype activity and side effects.

Morphometric sex determination of Milky and Painted Storks in captivity

Logistic regression was applied to develop a morphometric sexing method of two closely related stork species that were previously sexed through amplification of the CHD gene. Tarsus length (TL) and bill length (BL) measurements were recorded from captive populations of adult Milky Stork (Mycteria cinerea) (n = 60) and Painted Stork (Mycteria leucocephala) (n = 58) at Zoo Negara Malaysia. Despite having monomorphic plumages, both stork species exhibited normal sexual size dimorphism in which males were significantly larger than females in the tested variables. Based on logistic regression analysis, BL correctly classified the sex of sampled individuals from Painted and Milky stork with an overall predicted accuracy of 94.8 and 90.0%, respectively. However, TL measurements generated a lower predicted accuracy level of 86.2% and a same accuracy level of 90% on the sex classification of individuals from Painted and Milky stork, respectively. By comparing the measurements of both species, only the average BL measurements of the Milky storks were significantly lower than that of Painted storks (t-test, P80.001). The logistic regression equation in this study may serve as a simple and more practical option for sexing Milky and Painted storks for their breeding and conservation programmes.

Association between total serum calcium and the A986S polymorphism of the calcium-sensing receptor gene

Serum calcium is under tight physiological control, but it is also a quantitative trait with substantial genetic regulation. Mutations of the CASR gene cause familial hypocalciuric hypercalcemia or autosomal dominant hypoparathyroidism, depending on whether they decrease or increase, respectively, ligand binding to the receptor protein. We described an association between ionized calcium and a common polymorphism (A986S) found in the cytoplasmic tail of this G protein-coupled receptor. We report here on an independent study of 387 healthy young women. Genotyping was performed by allele-specific amplification and serum chemistries were measured by automated clinical assay. Frequencies of SS, AS, and AA genotypes were 6, 107, and 274, respectively, yielding a 986S allele frequency of 15.4%. Mean total serum calcium (Ca(T)) was significantly higher in the SS (9.88 +/- 0.29 mg/dL, P = 0.015) and AS groups (9.45 +/- 0.05 mg/dL, P = 0.002), than in the AA group (9.23 +/- 0.04 mg/dL). In multiple regression modeling, the A986S genotype remained an independently significant predictor of Ca(T) (P < 0.0001) when serum albumin, globulin, inorganic phosphate, and creatinine covariates were included. These data are the first to show significant association between a common polymorphism and concentrations of a serum electrolyte. The A986S polymorphism is also a potential predisposing factor in disorders of bone and mineral metabolism.

Chinese tonal language rehabilitation following cochlear implantation in children

Cantonese language rehabilitation in 28 prelingually deaf children who underwent cochlear implantation was evaluated. All patients were implanted with multichannel devices and the operations went smoothly. They all had improved scores on audiological assessments and speech perception tests. The speech evaluation tests included the recognition of sounds, vowels, consonants and tone. Sentence recognition and story comprehension were both improved after training for 2 years. Cochlear implantation is a useful measure for the speech rehabilitation of prelingually profound deaf children when hearing aids are of no benefit. The multichannel implant device is of clinical significance in the rehabilitation of those patients using tonal language.

Clearing hurdles in teacher adoption and sustained use of research-based instruction

Gersten et al., in this issue of JLD, have pinpointed variables that preclude teachers' sustenance of research-based instructional strategies. These variables fall squarely on the shoulders of intervention researchers. However, they have not attended to variables that stem from teachers themselves. Hence, in my commentary, I focus on teacher variables that account for their lack of initiation and sustenance of research-based instructional strategies. Specifically, I highlight teachers' (a) overarching conceptions of teaching, (b) subject-area knowledge, and (c) sense of self-efficacy. Of these, for reasons given in my article, I elaborate more on teacher self-efficacy. I conclude with suggestions on promoting teacher self-efficacy.

Production of genetically stable high-titer retroviral vectors that carry a human gamma-globin gene under the control of the alpha-globin locus control region

The ability to generate stable high-titer vectors that give rise to high levels of expression of transduced globin genes in erythroid cells is a prerequisite for effective retroviral-mediated globin gene therapy. The human beta-globin gene with its immediate flanking sequences does not contain all the regulatory elements necessary for regulated high-level and position-independent expression in erythroid cells. The regulatory element known as the beta-globin locus control region (BetaLCR) can provide a linked Beta-globin gene with these properties. However, addition of BetaLCR sequences to a retrovirus carrying a beta-globin gene increases its genetic instability. We have developed a new generation of retroviral vectors in which a human gamma-globin gene is placed under the control of the alphaLCR, the major regulatory element of the alpha-globin gene cluster. We demonstrate that these retroviruses are genetically stable in producer cell lines and can be produced at high titers that exceed 5 x 10(6) colony-forming units (CFU)/mL. In addition, we show that the transduced gamma-globin gene can be expressed in the adult erythroid environment of mouse erythroleukemia (MEL) cells at a level comparable to that of a single endogenous Betamaj-globin gene. These retroviruses can also transduce primary murine bone marrow progenitor cells as efficiently as retroviruses that carry the neomycin resistance (neor) gene. This new generation of globin retroviral vectors may prove useful for gene therapy of human beta-globin gene disorders such as sickle cell disease and beta-thalassemia.

Teaching low achievers and students with learning disabilities to plan, write, and revise opinion essays

A total of 38 problem learners comprising adolescents with learning disabilities and low achievers participated in this study. Of these, 20 were untrained control participants; the remainder were trained to plan, write, and revise opinion essays. Trainees were randomly divided into pairs and taught to collaboratively use interactive dialogues to plan and revise their essays (but they wrote their essays separately). The results from multivariate analyses of variance (MANOVAs) and effect sizes indicated that trainees improved significantly from pretest to posttest in clarity and cogency of written opinion essays, and maintained such gains. Additional analyses indicated that they surpassed the untrained control group. Questionnaire data indicated trainees improved in self-efficacy of writing only. The same finding held true in comparison with untrained participants. The discussion integrates the trainees' performance data with the questionnaire data and considers the research implications and limitations of the study.

Oldenlandia diffusa and Scutellaria barbata augment macrophage oxidative burst and inhibit tumor growth

Oldenlandia diffusa (OD) and Scutellaria barbata (SB) have been used in traditional Chinese medicine for treating liver, lung and rectal tumors. In this study we determined the effects of these phytochemicals on oxidative burst as an indicator of phagocytic function in a murine macrophage cell line J774 using an automated micro-fluorometric assay. A dose-dependent augmentation of oxidative burst was observed with OD as well as SB. The effect of OD and SB on the growth of a murine renal cell carcinoma (Renca) was also determined. Balb/c mice were transplanted subcutaneously with 1 x 10(5) Renca cells and were randomized into groups of 10 to receive oral feeding of OD (4 mg/day), SB (4 mg/day), or saline as control. Oral feeding with either OD or SB significantly inhibited the growth of Renca in mice. The data of this study show that OD and SB are capable of enhancing macrophage function in vitro and inhibiting tumor growth in vivo.

The ABL genes in normal and abnormal cell development

Genetic alteration of the c-abl protooncogene has led to abnormal cellular development, primarily within the hemopoietic system. Different forms of oncogenic alteration have variations in biological strength for cellular transformation. The abnormal Abl oncoproteins are known to suppress apoptosis, which may be the basis for causing leukemia development. However, recent evidence also shows that c-abl proto-oncoprotein can inhibit apoptosis. Expression of the Abl oncoprotein in hemopoietic stem cells (HSCs) also results in alteration in the expression of certain cell surface molecules such that the interaction between HSCs and their marrow stroma microenvironment has become abnormal. The basis for the genetic alteration of the c-abl protooncogene in patients with chronic myelogenous leukemia may or may not be due to genetic imprinting.

Transduction of rIL-2 expanded CD4+ and CD8+ ovarian TIL-derived T cell lines with the G1Na (neor) replication-deficient retroviral vector

We have expanded ovarian tumor-infiltrating lymphocytes (TIL) in low concentrations of recombinant interleukin-2 (rIL-2) to conduct intraperitoneal adoptive immunotherapy trials in patients with ovarian cancer. We have previously demonstrated that certain T cell lines and clones derived from ovarian TIL exhibit in vitro autologous tumor-specific cytotoxicity and/or cytokine production (interferon-gamma, tumor necrosis factor-alpha) preferentially in response to autologous tumor cells. Studies that utilize a marker gene introduced into the DNA of TIL can provide useful information on specific uptake or localization of TIL at tumor sites and on the survival of TIL in vivo. We have conducted a series of preclinical experiments in which we have successfully transfected TIL with G1Na, which encodes the gene for neomycin phosphotransferase (neoR). NeoR was detected in at least 10% of CD8+ cells (mean = 10.4%) and between 2.5 and 20% of CD4+ TIL (mean = 8.5%). Transduction of ovarian TIL with G1Na caused no substantial changes to the T cell phenotypes or in vitro cytotoxicities against ovarian and hematogenous tumor cell targets, or on the rIL-2 requirements of TIL for growth and proliferation. In addition, the intact G1Na provirus in transduced TIL cells was rescuable by replication-competent retrovirus and was transferred into the genome of NIH-3T3 fibroblasts, which were rendered resistant to G418. An enhanced polymerase chain reaction (PCR) procedure utilizing detection by ethidium bromide staining was developed. The enhanced PCR detected 1 in 100,000 neoR-labeled cells. Furthermore, detection of the G1Na genome in transduced TIL by in situ hybridization with an RNA probe provided evidence for expression of the neoR gene in transduced TIL. Results obtained from these studies suggest that ovarian TIL-derived T cell lines transduced with the neoR gene post infection with the G1Na retroviral vector can be utilized to examine the in vivo trafficking pattern of ovarian TIL-derived T cell lines expanded in low concentrations of rIL-2 and their survival.

High-efficiency identification of genes by functional analysis from a retroviral cDNA expression library

Retroviral gene transfer efficiently delivers genes of interest stably into target cells, and expression cDNA cloning has been shown to be highly successful. Considering these two advantages, we now report a method by which one can identify genes stimulating cell growth through functional analysis. The first step requires the construction of a retroviral cDNA expression library and the optimization of transfection of vector DNA into virus packaging cells. The second step involves the cocultivation of target cells with libraries of retrovirus-producing cells, resulting in the amplification of target cells transduced with a gene(s) stimulating cell growth. Under standardized conditions of transfection, we detected an average of 4,000 independent clones per dish, among which expression of a retroviral beta-galactosidase gene at an abundance of 0.2% could be detected. Next, we demonstrated the augmentation of the sensitivity of the assay by retroviral infection and functional analysis. We did this by cocultivating factor-dependent (FD) cells with dishes of GP/E cells transfected with plasmids containing various molar ratios of pN2-IL3 DNA and retroviral library cDNA and by determining the highest dilution of pN2-IL3 which still resulted in the conversion of FD cells to factor independence. The retroviral interleukin-3 gene at an abundance as low as 0.001% could be detected. Indeed, we were able to detect from FD cells the development of factor-independent colonies with different phenotypes after retroviral transfer of cDNAs from an immortalized hemopoietic stem cell line. Thus, the combination of a standardized high-efficiency DNA transfection and retrovirus-mediated gene transfer should facilitate the identification of genes capable of conferring to target FD cells a detectable new function or phenotype. By scaling up the size of the experiment realistically during screening, the assay can detect cDNA at an abundance of lower than 0.0001%.

Inducing adaptive coping self-statements in children with learning disabilities through self-instruction training

This study investigated the efficacy of a coping strategy in reducing math anxiety in children with learning disabilities (LD). The coping strategy was based on cognitive behavior modification (CBM). Twenty children from Grades 4 to 7 participated in the study. Half of them were children with LD and the remaining were normally achieving children. The dependent measures were self-talk data and performance data on math (fraction) problems. Pretest data indicated that normally achieving children produced substantially more positive self-talk than children with learning disabilities. Subsequent to training in the use of the CBM-based coping strategy, children with LD produced a comparable amount of positive self-talk at posttest as found in normally achieving children. Moreover, there was a moderate, positive correlation between increased positive self-talk and math performance among the children with LD. The results clearly indicated that the children with LD had learned to cope with their math anxiety via a CBM-based strategy. More generally, the results of the study suggest that CBM strategies can be effectively applied to the affective domain. This broader implication and the limitations of the study are discussed.

Inhibition of dexamethasone-induced cytochrome P450-mediated mutagenicity and metabolism of aflatoxin B1 by Chinese medicinal herbs

Oldenlandia diffusa (OD) and Scutellaria barbata (SB) have been used in traditional Chinese medicine for treating liver, lung and rectal tumours. We previously showed that they inhibited mutagenesis, DNA binding and metabolism of aflatoxin B1 (AFB1) and benzo(a)pyrene (BaP) bioactivated by Aroclor 1254-induced rat S9. The purpose of this study was to investigate the effects of OD and SB on the mutagenicity of AFB1 in Salmonella typhimurium TA100 using dexamethasone (DXM)-induced rat hepatic S9, on cytochrome P450-linked aminopyrine N-demethylase (APND) activity in DXM-induced hepatic microsomes and on the metabolism of AFB1 by DXM-induced S9 using high-performance liquid chromatography (HPLC). The experimental results showed that OD and SB consistently inhibited the mutagenicity of AFB1 bioactivated by either non-induced or DXM-induced S9. These effects correlated with the inhibition of cytochrome P450-linked APND activity in DXM-induced microsomes and with an inhibition of DXM-induced S9 mediated metabolism of [3H]AFB1 as determined by HPLC. Since DXM treatment has been associated with an induction of the CYP3 enzyme family, these results suggest that OD and SB may possess antimutagenic and antitumorigenic activity towards AFB1 through an inhibition of CYP3-mediated metabolism of AFB1.

Comparing two modes of teaching a question-answering strategy for enhancing reading comprehension: didactic and self-instructional training

This study investigated the comparative efficacy of two instructional approaches--didactic teaching and self-instructional training--in teaching average and poor readers a comprehension question-answering strategy. Forty-five average students and 45 poor readers from Grades 5 and 6 participated. These 38 girls and 52 boys were equally and randomly assigned to one of three treatment conditions: didactic teaching of the strategy, self-instruction, or control (no training). Students in the first two treatment conditions learned a mnemonic strategy ("Here," "Hidden," and "in my Head") to indicate question-answer relationships that are text explicit, text implicit, or script implicit, respectively. Essentially, the 3H mnemonic cued students to use appropriate text and/or knowledge-base information in answering comprehension test questions. In addition, students in the self-instruction group learned three self-questions to guide their use of the 3H strategy. Specifically, the self-questions focused students' attention on the task, provided a basis for decision making concerning the categorization of comprehension test questions, and reminded students to check their answers. The results indicated that both didactic teaching and self-instructional training of the strategy effected significant improvements in students' reading comprehension performance. However, self-instructional training was more effective in enhancing and maintaining students' reading comprehension performance than didactic teaching. Moreover, results from the oral questionnaire indicated that the 3H strategy training increased students' general meta-cognitive knowledge. Lastly, of the 60 trained students, 52 wrote that they would encourage other children to learn the 3H strategy. Thus, the response to strategy learning was clearly positive.

Modulation of cytochrome P-450IA1-mediated mutagenicity, DNA binding and metabolism of benzo[a]pyrene by Chinese medicinal herbs

Oldenlandia diffusa (OD) and Scutellaria barbata (SB) have been used in traditional Chinese medicine for treating liver, lung and rectal tumors. We previously showed that they inhibited mutagenesis, DNA binding and metabolism of benzo[a]pyrene (BaP) and aflatoxin B1 (AFB1) bioactivated by Aroclor 1254-induced rat hepatic S9. The purpose of this study was to investigate the effects of OD and SB on the cytochrome P-450IA1-mediated mutagenicity of BaP in Salmonella typhimurium TA100 using beta-naphthoflavone (beta NF)-induced rat hepatic S9. We also determined the effects of OD and SB on cytochrome P-450IA1-linked ethoxyresorufin O-deethylase (EROD) activity in beta NF-induced hepatic microsomes. In addition, we studied the effects of these two herbs on BaP metabolite binding to calf thymus DNA and using high performance liquid chromatography (HPLC) we investigated the effects of OD and SB on the metabolism of BaP by beta NF-induced S9. Our experimental results showed that OD and SB inhibited the mutagenicity of BaP in the presence of either non-induced or beta NF-induced S9. SB significantly inhibited BaP binding to DNA. These effects correlated with the inhibition of cytochrome P-450IA1-linked EROD activity in beta NF-induced microsomes and with an inhibition of beta NF-induced S9 mediated metabolism of [3H]BaP as determined by HPLC. These results suggest that OD and SB may possess antimutagenic activity by inhibiting P-450IA-mediated metabolism of BaP.

Chinese medicinal herbs modulate mutagenesis, DNA binding and metabolism of aflatoxin B1

Oldenlandia diffusa (OD) and Scutellaria barbata (SB) have been used in traditional Chinese medicine for treating liver, lung and rectal tumors while Astragalus membranaceus (AM) and Ligustrum lucidum (LL) are often used as an adjunct in cancer therapy. In this study, we determined the effects of aqueous extracts of these four herbs on aflatoxin B1 (AFB1)-induced mutagenesis using Salmonella typhimurium TA100 as the bacterial tester strain and rat liver 9000 x g supernatant as the activation system. The effects of these herbs on [3H]AFB1 binding to calf-thymus DNA were assessed. Organosoluble and water-soluble metabolites of AFB1 were extracted and analyzed by high-performance liquid chromatography (HPLC). Mutagenesis assays revealed that all of these herbs produced a concentration-dependent inhibition of histidine-independent revertant (His+) colonies induced by AFB1. At a concentration of 1.5 mg/plate, SB and OD in combination exhibited an additive effect. The trend of inhibition of these four herbs on AFB1-induced mutagenesis was: SB greater than LL greater than AM. LL, OD and SB significantly inhibited AFB1 binding to DNA, reduced AFB1-DNA adduct formation, and also significantly decreased the formation of organosoluble metabolites of AFB1. Our data suggest that these Chinese medicinal herbs possess cancer chemopreventive properties.

Chinese medicinal herbs modulate mutagenesis, DNA binding and metabolism of benzo[a]pyrene 7,8-dihydrodiol and benzo[a]pyrene 7,8-dihydrodiol-9,10-epoxide

Oldenlandia diffusa(OD) and Scutellaria barbata (SB) have been used in traditional Chinese medicine for treating liver, lung and rectal tumors. In this study, the effects of aqueous extracts of these two herbs on benzo[a]pyrene 7,8-dihydrodiol. (BaP 7,8-DHD) and benzo[a]pyrene 7,8-dihydrodiol-9,10-epoxide (BPDE)-induced mutagenesis using Salmonella typhimurium TA100 as the bacterial tester strain and rat liver 9000 x g supernatant (S9) as the metabolic activation system were assessed. We also determined the effects of these two herbs on BaP 7,8-DHD and BPDE binding to calf thymus DNA. Organosoluble metabolites of BaP 7,8-DHD and water-soluble conjugates of BaP 7,8-DHD and BPDE were analyzed by high-performance liquid chromatography (HPLC) and alumina column liquid chromatography. Mutagenesis assays revealed that these two herbs produced a significant concentration-dependent inhibition of histidine-independent (His+) revertants induced by BaP 7,8-DHD and BPDE. OD and SB also inhibited BPDE-induced mutagenesis in a concentration-dependent manner in the absence of S9. SB had a greater inhibitory effect than OD. SB significantly inhibited BaP 7,8-DHD and BPDE binding to DNA while OD significantly enhanced DNA binding of both compounds. OD and SB inhibited the formation of organosoluble metabolites of BaP 7,8-DHD and decreased the formation of water-soluble conjugates of BaP 7,8-DHD and BPDE. However, the fraction of the total radioactivity in the water-soluble conjugates present as sulfate and glutathione was increased by OD and SB. Glucuronide fraction was decreased. The results of this study affirm our previous work suggesting that these two Chinese medicinal herbs possess antimutagenic properties and further suggest that they act as blocking agents through a scavenging mechanism.

The lateral spread of ictal discharges in neocortical brain slices

The in vitro brain slice technique was used to examine the lateral propagation of spontaneous electrographic ictal episodes across adjacent areas of guinea pig neocortex. Epileptiform activity was induced by perfusing slices with Mg-free artificial CSF. Simultaneous field potential recordings of ictal episodes were obtained from 4 micropipettes placed 1-3 mm apart across coronal slices in middle-cortical layers. Two types of lateral spread were characterized. Ictal episodes often developed focally and then spread as a slowly moving wavefront traveling at less than 0.3 mm/sec into adjacent, uninvolved cortex. By contrast, other episodes began nearly synchronously at all cortical sites. The individual afterdischarges that composed each ictal episode propagated rapidly across the cortex at greater than 30 mm/sec and were triggered by multiple pacemakers. Ictal episodes always terminated abruptly across the entire slice. The NMDA-receptor antagonist, 2-amino-phosphono-valerate, applied focally between recording sites, blocked rapid propagation across treated areas and resulted in the emergence of spatially separate, independent pacemakers. Pacemaker failure is the proposed mechanism for simultaneous and generalized termination of ictal episodes in this in vitro model of epileptogenesis.

Magnetic resonance imaging of vascular compression in trigeminal neuralgia. Case report

A case of trigeminal neuralgia is reported in which preoperative high-resolution magnetic resonance imaging demonstrated vascular compression of the trigeminal nerve. Surgery confirmed compression and indentation of the fifth nerve by a large branch of the superior cerebellar artery. Following microvascular decompression, the patient experienced no further pain. Magnetic resonance imaging may be useful in the evaluation of trigeminal neuralgia to identify a subgroup of patients who could benefit most from decompression.

Dextrorphan and dextromethorphan, common antitussives, are antiepileptic and antagonize N-methyl-D-aspartate in brain slices

The antitussive, dextromethorphan (DM), and its metabolite, dextrorphan (DX), were evaluated for antiepileptic properties in vitro. Interictal bursts and prolonged ictal epileptiform afterdischarges, induced by perfusion of guinea pig neocortical brain slices with Mg2+-free solution, were blocked by DX (1-250 microM) or DM (100 microM). Intracellular records showed that these agents blocked N-methyl-D-aspartate (NMDA)-induced depolarizations without altering intrinsic membrane properties. DX blocked NMDA but not quisqualate-evoked multi-unit excitatory responses. DM is a widely available, orally effective drug with low toxicity in antitussive doses, which has antiepileptic and NMDA-antagonist properties in vitro. Its toxicity and effectiveness as an anticonvulsant should be expeditiously examined in clinical trials.

Nigral infusions of muscimol or bicuculline facilitate seizures in developing rats

The substantia nigra (SN) appears to be a crucial site involved in the modification of seizures. The aim of this study was to elucidate the role of the GABA nigral system in the expression of seizures by comparing the effects of multiple doses of a GABA agonist (muscimol) and a GABA antagonist (bicuculline methobromide) on the development of flurothyl seizures in 16-day-old rat pups. The drugs were infused bilaterally either in the SN or dorsal to the SN. An additional group of pups were infused with bicuculline in the corpus striatum. Results indicate that both drugs facilitated the development of seizures in a dose-related manner when infused into the SN. Infusions of muscimol dorsal to the SN had no effect on seizure latencies while infusions of bicuculline dorsal to SN or corpus striatum still increased the susceptibility of rat pups to seizures. The data suggest that only the effects of muscimol on seizures are specific for the SN and that early in life muscimol may exert its proconvulsant effects via a different receptor site or mechanism than bicuculline.

Mutual interactions between repeated flurothyl convulsions and electrical kindling

The interactions between repeated flurothyl seizures and electrical kindling induced from the neocortex or the amygdala were investigated. Three consecutive flurothyl-induced convulsions enhanced the rate of development of subsequent electrical kindling from the neocortex. Similarly multiple (more than 15) generalized kindled seizures, induced from either the neocortex or the amygdala, reduced the latency of onset of flurothyl seizures with repeated exposures producing a 'kindling-like' effect for flurothyl. These results indicate that eventually seizures will beget seizures independently of the site of origination of the seizures.

Age-related substantia nigra-mediated seizure facilitation

We investigated the role of the GABAergic system of the substantia nigra in seizures of rat pups. Rat pups had bilateral cannulae implanted chronically either in the substantia nigra or 1.5 mm dorsal to it. At age 16 to 17 days, seizures were induced in the cannulated rats and naive (intact) controls by exposure to flurothyl following pretreatment with the GABA agonist, muscimol, or vehicle. Naive rats were the most resistant to flurothyl seizures. Bilateral nigral infusions of muscimol markedly facilitated the development of flurothyl seizures in a dose-response manner and differed significantly from the vehicle controls or rats infused with muscimol dorsally to the substantia nigra. In contrast, bilateral nigral muscimol infusions protected adult rats against the development of flurothyl seizures. Our data indicate that the effects of nigral GABA agonist infusions on seizures are age-dependent; the altered responsivity of the GABAergic nigral system in immature rats may be responsible in part for the increased seizure susceptibility of the developing central nervous system.

The day-care centre in the management of psoriasis

In 1980, 118 patients with psoriasis were admitted to the inpatient service of MRH resulting in 3048 patient days of hospitalisation. The day care centre for psoriasis can provide an efficient therapeutic environment thus reducing hospital admissions. The outpatient dithranol-ultraviolet B combination therapy gave a 80% success in clearing 95% of the skin of psoriasis. PUVA therapy gave a clearance of 77% requiring an average of 25 treatment sessions; taking an average of 42 days and total UVA dose of 346 J/cm2. Combination therapy of retinoids and PUVA (REPUVA) gave a success rate of 96% clearance with an average of 18 treatment sessions and average total UVA dose of 142 J/cm2.

Issues in cognitive-behavioral interventions in academic skill areas

In this paper, conceptual and methodological issues within three phases of CBM interventions in academic skills are analyzed: Acquisition, evaluation, and generalization. The goal of such analysis is threefold: To enhance understanding of observed problems, clarify specific conceptual issues, and highlight areas that need more conceptual clarification and more research.

Simple method for maintaining serum lidocaine levels in the therapeutic range

Lidocaine hydrochloride is commonly infused intravenously to prevent ventricular arrhythmias. In some patients, elevations in serum lidocaine levels can cause serious toxic effects. In a group of 19 patients given a constant infusion of lidocaine, we confirmed the observation that serum lidocaine levels rose significantly between four and 24 hours after initiation of therapy. One of these patients manifested a toxic reaction to lidocaine. The lidocaine infusion rate was modified in a second group of 32 patients on the basis of the four-hour serum level. In these patients, after dosage adjustment, the mean lidocaine level did not rise, and all levels remained within the 2- to 4-mg/L therapeutic range at 24 hours. Without dosage adjustment, half of these levels would have fallen outside the desired range. A simple formula can be used to adjust prophylactic lidocaine infusion rates to attain levels that remain therapeutic, yet nontoxic.

Investigating awareness of and teaching passage organization in learning disabled children

This study explored sensitivity to passage organization and its importance in governing the ease of learning a passage in normally achieving and learning disabled children. The results indicated that normally achieving children were more aware of passage organization than learning disabled children. However, both groups focused on dimensions such as sentence length, decoding and vocabulary difficulty and informational load, rather than passage organization as determinants of task difficulty. Moreover, unlike normally achieving children, learning disabled children had substantial difficulties in reorganizing a disorganized passage. Through subsequent training, they learned to sort disorganized sentences into coherent clusters around respective subtopics, and appeared to understand what constitutes an organized paragraph within a passage.

Comparability of self-concept among learning disabled, normal, and gifted students

Using randomly formed groups of fourth-to seventh-grade learning disabled, normal, and gifted students, the comparability of representations of self-concept across groups was analyzed for the Sears and Coopersmith inventories. Additionally, mean differences across the three groups of students were calculated on self-concept subscales. Subscale representations of the construct were judged comparable across groups. Whereas a reliable linear trend on academic self-concept subscales favored gifted and normal students over learning disabled students, learning disabled children slightly exceeded gifted children on physical and social facets of self-concept from the Sears inventory only. Implications for validity research and evaluation studies are discussed.

Diagnosis of pericardial effusion by computed tomography

We assessed the diagnostic utility of computed tomography (CT) in the detection of pericardial effusion by using a dog model in which the amount and type of pericardial fluid were controlled and by obtaining CT scans on patients with suspected pericardial effusion prior to pericardiocentesis. The experimental studies showed that CT was capable of detecting pericardial effusion composed of serous fluid or saline in amounts as small as 50 ml. However, the hemopericardium was radiographically isodense with the heart and difficult to detect by CT unless the epicardial fat pad was identified or intravenous contrast enhancement of the heart was used. CT clearly demonstrated the presence of pericardial effusion in all six patients studied prior to successful pericardiocentesis or pericardiectomy. We conclude that CT is a sensitive noninvasive method which can be used for the diagnosis of pericardial effusion.

Strategic behaviors in selecting retrieval cues in gifted, normal achieving and learning-disabled children

This study investigated organized strategies and self-checking behaviors in selecting retrieval cues in gifted, normal-achieving and learning disabled children. The results indicated that compared to the others, LD children lacked self-checking skills. Moreover, they were less exhaustive than the others in their selective search of retrieval cues. However, they did use some form of organized strategy in selecting the retrieval cues. Such organized strategy appears to be less efficient than that of gifted children. Additionally, unlike the gifted, both normal-achieving and LD children failed to choose retrieval cues of maximal use in aiding recall. The results also indicated that prior recall of the story resulted in all children choosing more items of most thematic importance. Generally, the results were taken to support Torgesen's conceptualization of LD children as inactive learners.

Progression of aortic stenosis

We assessed progressive stenosis of the aortic valve in 11 adult patients (mean age of 48 years) with aortic stenosis who had undergone two cardiac catheterizations without intervening aortic valve surgery. The mean time between cardiac catheterization was 59 months (range 20 to 133). No patients had mitral valve disease. Two patients had coronary artery disease. The results showed that progressive stenosis of the aortic valve occurred in 10 of 11 patients with a significant decrease in the calculated mean aortic valve area from 1.2 +/- 0.2 sq cm to 0.7 +/- 0.1 sq cm (P less than 0.005); a significant increase in mean left ventricular peak systolic pressure from 149 +/- 8 mm Hg to 199 +/- 3 mm Hg (P less than 0.01), and a significant increase in mean left ventricular aortic pressure gradient from 31 +/- 4 mm Hg to 75 +/- 13 mm Hg (P less than 0.005). On an individual basis, the change in left ventricular pressure and the left ventricular-aortic gradient did not always reflect the decrease in aortic valve area because of variations in cardiac output. The shortest period of time in which progression of aortic stenosis occurred was 27 to 29 months. Thus, progressive stenosis of the aortic valve occurs in adults with isolated aortic valvular stenosis. Significant decrease in the aortic valve area can develop in as short a period as 27 to 29 months.

Treatment of heart block due to sarcoid heart disease

The role of glucocorticosteroid therapy for myocardial sarcoidosis is not well defined. This report shows the effect of prednisone therapy on atrioventricular (AV) conduction in a patient with myocardial sarcoidosis and AV block. On three separate occasions AV block was documented prior to prednisone therapy. On the first two occasions the patient had first and second degree AV block which by His bundle electrogram initially was shown to be in the AV node. On the third occasion the patient developed complete heart block. On each occasion treatment with prednisone resulted in improved AV conduction. The results indicate that prednisone therapy can be beneficial in the treatment of AV block due to myocardial sarcoidosis.

Echocardiographic features of an aneurysm of the left sinus of Valsalva

The echocardiographic features of an aneurysm of the left sinus of Valsalva are described and correlated with angiographic findings. The echocardiogram showed the presence of a thin line of echoes occurring proximal to the anterior leaflet of the mitral valve and moving in and out of apposition with the posterior aortic wall. During systole, this line of echoes moved away from the aorta into the left atrium, and during diastole, the line moved into the aorta. Recognition of these features provides a potential noninvasive way to diagnose aneurysms of the left sinus of Valsalva prior to rupture.

Physiologic determinants of left ventricular strength-interval curve of the dog

Strength-interval curves, relating an index of the contractile vigor of premature beats to their coupling intervals, were elicited in anesthetized, open-chest dogs prepared for atrial or ventricular pacing and the high-fidelity measurement of left ventricular pressure. During inotropic interventions, changes of the curves were evaluated in terms of the parameters (slopes and intercepts) of their straight lines of best fit. These parameters were altered by isoproterenol, propranolol, and heart rate, and were correlated closely with paired values of isovolumic Vmax (of driven beats). The strength-interval curves were reproducible and were not affected by large changes of venous return or arterial blood pressure. These results provide a basis for the use of strength-interval curves for the evaluation of ventricular contractile state, using fluid-filled catheters for the measurement of left ventricular pressure.

Effect of regional myocardial ischaemia on left ventricular isovolumic contraction

In anaesthetised, open-chest dogs, global isovolumic contractility indices were reduced by acute regional ischaemia involving 12 to 14% or more of left ventricular mass. These effects were not altered by controlled reduction of blood flow to the non-ischaemic region, but were exaggerated by isoprenaline during normal perfusion of the non-ischaemic region. The results were consistent with a contraction model characterised by simple reduction of the effective length of the contractile elements.

Clinical significance of the V wave in the main pulmonary artery

Among 68 patients with mitral insufficiency who had right and left cardiac catheterization and left ventriculography, 6 had retrograde transmission of the left atrial V wave into the main pulmonary artery. All of these patients had mitral insufficiency of acute onset. The remaining 62 patients had chronic mitral insufficiency that was considered severe in 17. Pulmonary vascular resistance was lower in the group with acute insufficiency (mean 139 dynes sec cm-5) than in the group with chronic severe insufficiency (mean 631 dynes cm-5) (P less than 0.005). Nondistensibility of the left atrium and low pulmonary vascular resistance were the two factors favoring retrograde transmission of V waves. Because both factors are present in acute mitral regurgitation, this finding is helpful in differentiating patients with acute mitral insufficiency.

Transient unifascicular, bifasicular and trifascicular block: electrophysiologic correlations in a patient with rate-dependent left bundle branch block and transient right bundle branch block

Correlations of the His to ventricular (H-V) conduction time were made with the surface electrocardiogram during normal intraventricular conduction, unifascicular block (right bundle branch block), bifascicular block (left bundle branch block) and trifascicular block (right and left bundle branch block) in a patient with rate-dependent left bundle branch block who had transient right bundle branch block during recording of the His bundle electrogram. The results provide a functional confirmation of the theory that a prolonged H-V time is a manifestation of trifascicular disease.

Pulmonary arterial pulsus alternans secondary to primary pulmonary hypertension

Pulsus alternans of the pulmonary artery without systemic pulsus alternans is uncommon and is associated with multiple diseases. Two cases of pulmonary hypertension with pulmonary arterial pulsus alternans and right-sided heart failure are described. Primary pulmonary hypertension was demonstrated at autopsy in both cases. These two case reports constitute another previously unreported cause for pulsus alternans in the pulmonary circuit.