Recurrent wavefront morphologies: A method for quantifying the complexity of epicardial activation patterns

We have developed a method for quantifying the complexity of activation patterns observed during ventricular fibrillation (VF) that is based on our previously reported methodology for decomposing epicardial mapping data into a set of isolated wavefronts. One-half second datasets are acquired from a 21×24 array of unipolar electrodes (1 mm spacing), and the wavefronts are isolated. A correlation technique is used to compute the similarity between all possible pairs of the isolated wavefronts. From these data, the wavefronts are sorted into clusters, each of which represents a recurring wavefront morphology. We define multiplicity (M) as the number of clusters needed to account for 90% of the total activations in the VF episode.M measures the complexity of the rhythm. In repetitive patterns (e.g., sinus rhythm),M=1, indicating that the same morphology repeatedly activates the mapped region. Typically, in VF,M>1, with larger numbers representing more complex, disorganized patterns. As an example, we computedM at 5, 10, 15, and 20 sec after electrical induction of VF in six pigs.M decreased significantly (p<0.001), suggesting increasing organization during this period.     

Reproductive tract abnormalities in rats treated neonatally with DES

Neonatal female Sprague-Dawley rats were given daily injections of 3 μg diethylstilbestro (DES) for 5 days beginning within 24 hours of birth. Some of these rats were ovariectomized between the 15th and 18th postnatal days, and on the 60th postnatal day were given daily injections of 3 μg estradiol for 1, 3, or 5 weeks. Intact rats were sacrificed at 60, 95, or 130 days. The morphology of the upper vagina, cervix, and lower uterus was examined by light and scanning electron microscopy. Two abnormalities resulting from neonatal DES exposure were found. The first was squamous metaplasia observed in the uteri of rats given DES and later exposed to exogenous or endogenous estrogen. Metaplasia was seen in both the luminal and glandular epithelium. The longer the rats were exposed to exogenous or endogenous estrogen, the more extensive was the metaplasia. The second was a gross morphologic abnormality seen in all rats given DES regardless of any later treatment. That part of the cervix that protrudes into the cranial limit of the vagina was absent and, thus, a vaginal fornix was nonexistent. Previous investigations have emphasized abnormalities of the lower reproductive tract. The present study indicates that the upper reproductive tract also must be considered in investigations of the effects of hormones administered to neonates.     

Clusterin, a marker for anaplastic large cell lymphoma immunohistochemical profile in hematopoietic and nonhematopoietic malignant neoplasms

We evaluated the immunohistochemical staining profile of clusterin in paraffin sections of 143 neoplasms (non-Hodgkin lymphoma, 83, including 41 anaplastic large cell lymphomas [ALCLs]; Hodgkin lymphoma, 17; primary and metastatic carcinoma, 30; and other neoplasms, 13). In 40 of 41 ALCLs (34 systemic, 7 cutaneous), neoplastic cells revealed clusterin reactivity characterized by a Golgi staining pattern. The proportion of reactive cells varied with more than 25% positive cells in the majority of cases. In 7 non-Hodgkin lymphomas of other types, fine cytoplasmic (3 cases) or strong membranous reactivity (4 cases) was observed for clusterin. In Hodgkin lymphoma, rare Reed-Sternberg cells exhibited focal cytoplasmic or membranous clusterin positivity. In the nonhematopoietic neoplasms, a Golgi staining pattern was apparent in only 2 cases, 1 lobular carcinoma of the breast and 1 poorly differentiated colonic carcinoma; however, cytoplasmic reactivity was noted in 12 of 30 carcinomas and 1 of 5 neuroendocrine neoplasms. A Golgi pattern of reactivity for clusterin seems highly characteristic of ALCL among hematopoietic neoplasms, but also might be observed in rare nonhematopoietic tumors, necessitating the use of a broad immunohistochemical panel for evaluation of poorly differentiated neoplasms of indeterminate derivation.     

Nodal and paranodal structural changes in frog optic nerve during early Wallerian degeneration

Summary Ultrastructural changes in the nodal and paranodal regions of myelinated nerve fibres of frog optic nerves were studied during early stages of Wallerian degeneration. The earliest changes seen include retraction of paranodal loops of myelin from the axolemma and disconnection of paranodal myelin loops from myelin lamellae. These paranodal changes are asymmetric around the node and may be more advanced on either the proximal or distal side. Axoplasmic changes, including segregation of microtubules from neurofilaments, disorientation of microtubules and accumulation of abnormal organelles at nodes, appear shortly. In some axons the undercoating along the widened nodal surfaces becomes patchy, and blebs appear in the nodal axolemma. In freeze-fracture replicas a mixture of particle clusters and particle-free areas appears in both E- and P-faces of the nodal axolemma. Blebs remain particle free. Initially, E-face particles remain segregated to the node and are present only at much lower concentrations in the demyelinated paranodal axolemma, suggesting that they are not freely mobile at this stage. Nodal E-face particles begin to decrease on day 5 associated with an increase in particles at the adjacent demyelinated paranode, and by day 11 the particle distribution is uniformly low over the entire extent of the nodal and demyelinated paranodal axolemma. If nodal E-face particles represent sodium channels, as has been proposed, the sequence of changes in Wallerian degeneration would be compatible with a gradual redistribution of nodal sodium channels into the demyelinated paranode.     

Enhancement of attention in man with ACTH/MSH 4–10

Normal men were infused for 4 hr with ACTH/MSH 4–10 or a control solution. Behavioral testing after the infusion indicated that subjects who received ACTH/MSH 4–10 were less anxious and had better visual memory than control subjects but the predominant effect of the heptapeptide was to increase visual attention. It was specualted that ACTH/MSH 4–10 may be uniquely coded for attentional functioning.     

Pathogenesis of Herpetic Neuritis and Ganglionitis in Mice: Evidence for Intra-Axonal Transport of Infection

The pathogenesis of acute herpetic infection in the nervous system has been studied following rear footpad inoculation of mice. Viral assays performed on appropriate tissues at various time intervals indicated that the infection progressed sequentially from peripheral to the central nervous system, with infectious virus reaching the sacrosciatic spinal ganglia in 20 to 24 hr. The infection also progressed to ganglia in mice given high levels of anti-viral antibody. Immunofluorescent techniques demonstrated that both neurons and supporting cells produced virus-specific antigens. By electron microscopy, neurons were found to produce morphologically complete virions, but supporting cells replicated principally nucleocapsids. These results are discussed in the context of possible mechanisms by which herpes simplex virus might travel in nerve trunks. They are considered to offer strong support for centripetal transport in axons.     

Heart rate reactivity and heart period variability throughout the first year after heart transplantation

Heart rate reactivity to mental stress is substantially blunted early after heart transplantation, suggesting that the loss of neural modulation limits the cardiovascular response to mental stress. We tested whether reactivity to mental stress recovers during the first year after heart transplantation. Hemodynamic and respiratory responses to mental arithmetic challenge were studied in 20 heart transplant recipients 3, 6, and 12 months after surgery. A normal comparison group was studied at equivalent intervals. Heart rate reactivity to mental arithmetic was significantly reduced in the cardiac transplant group compared to the normal subjects. This effect persisted up to 1 year after transplantation. Heart period variability in the heart transplant recipients was minimal in all three-test sessions. The findings suggest that no functional reinnervation or other compensatory adaptation occurs up to 1 year after heart transplantation.     

Are Compulsive Checkers Impaired in Memory? A Meta‐Analytic Review

Researchers have hypothesized that compulsive checkers suffer from impairment in explicit memory (e.g., Sher, Frost, & Otto, 1983 ), low confidence in explicit memory (e.g., McNally & Kohlbeck, 1993 ), or both. However, empirical findings have been equivocal, possibly due to variability in effect sizes produced by small samples. Combining data across studies may yield more meaningful conclusions than can be surmised from a narrative review. Following a brief review of the literature on checking and memory, we present meta-analytic results suggesting that checkers are impaired on many types of memory tasks (e.g., verbal free recall, verbal cued recall, and recall of actions) and are less confident in recognition than noncheckers. We discuss implications of these findings, suggestions for future research, and limitations of this analysis.     

Acceptability of Interventions for Pediatric Pain Management

Examined the effects of pain symptom severity and patient diagnosticstatus on pediatric staffs' acceptability ratings of 6 interventionsused to treat pediatric pain. Results indicated that (a) extinctionwas significantly less acceptable than all other behavioraland pharmacologic interventions, (b) self-management was moreacceptable than all other interventions with the exception ofcontingency management, (c) accelerative procedures and self-managementinterventions were preferred to pharmacologic treatment, (d)patient diagnostic status and pain symptom severity failed tosignificantly influence treatment ratings, (e) self-managementwas the only intervention differentially rated as a functionof pain symptom severity, and (f) pharmacologic treatment wasdifferentially rated as a function of patient diagnostic status.     

Shuttle vectors for <Emphasis Type="Italic">Candida albicans</Emphasis>: control of plasmid copy number and elevated expression of cloned genes

Plasmids containing the inosine monophosphate dehydrogenase gene CaIMH3 from Candida albicans strain ATCC 32354 transform their host to resistance against mycophenolic acid (MPA). The transformants maintain the plasmids at a high copy number (20–40 per cell) and express the CaIMH3 gene at very high levels relative to untransformed controls. The plasmid copy number can be controlled by the concentration of MPA in the media. The transformation procedure is reproducible and the efficiency of transformation is high, up to 15,000 per microgram. Unrearranged plasmids are readily recovered by transforming total DNA from transformants back into Escherichia coli. C. albicans genes cloned into the plasmid are expressed at elevated levels relative to untransformed controls. A derivative vector containing the CaMAL2 promoter and termination sequences expresses the CaERG11 ORF at high levels and confers moderate resistance to fluconazole. These shuttle vectors should facilitate global genomics approaches in C. albicans that have been hampered by its diploid genome.