Plant size, latitude, and phylogeny explain within-population variability in herbivory

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sparse data. We collected standardized surveys of herbivory for 503 plant species at 790 sites across 116° of latitude. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth.

Comparative safety profile of chloral hydrate versus other sedatives for procedural sedation in hospitalized infants

BACKGROUND

Given the limited available evidence on chloral hydrate safety in neonatal populations and the discrepancy in chloral hydrate acceptance between the US and other countries, we sought to clarify the safety profile of chloral hydrate compared to other sedatives in hospitalized infants.

METHODS

We included all infants <120 days of life who underwent a minor procedure and were administered chloral hydrate, clonidine, clonazepam, dexmedetomidine, diazepam, ketamine, lorazepam, midazolam, propofol, or pentobarbital on the day of the procedure. We characterized the distribution of infant characteristics and evaluated the relationship between drug administration and any adverse event. We performed propensity score matching, regression adjustment (RA), and inverse probability weighting (IPW) to ensure comparison of similar infants and to account for confounding by indication and residual bias. Results were assessed for robustness to analytical technique by reanalyzing the main outcomes with multivariate logistic regression, a doubly robust IPW with RA model, and a doubly robust augmented IPW model with bias-correction.

RESULTS

Of 650 infants, 497 (76%) received chloral hydrate, 79 (12%) received midazolam, 54 (8%) received lorazepam, and 15 (2%) received pentobarbital. Adverse events occurred in 41 (6%) infants. Using propensity score matching, chloral hydrate was associated with a decreased risk of an adverse event compared to other sedatives, risk difference (95% confidence interval) of -12.79 (-18.61, -6.98), p <  0.001. All other statistical methods resulted in similar findings.

CONCLUSION

Administration of chloral hydrate to hospitalized infants undergoing minor procedures is associated with a lower risk for adverse events compared to other sedatives.

Cortisol directly determined in serum by fluoroimmunoassay with magnetizable solid phase

We developed a direct fluoroimmunoassay for cortisol in serum. This method involves cortisol labeled at the 3 position with fluorescein, and antibodies to cortisol coupled to magnetizable cellulose/iron oxide particles. Sodium salicylate is used as a blocking agent to prevent interference from endogenous binding proteins in serum. Serum sample and labeled cortisol are incubated with the antibody-coupled solid phase for 30 min. The solid phase is then separated and washed to remove free labeled cortisol and endogenous fluorophores of the sample. Finally we elute the antibody-bound fraction of the labeled cortisol into an alkaline methanolic medium and measure its fluorescence. The separation, wash, and elution steps are facilitated by magnetic sedimentation. The assay is sufficiently sensitive, specific, and reliable for routine use and correlates acceptably (r = 0.92) with an established radioimmunoassay. Precision (CV) ranged from 4 to 10% in experiments on three pooled sera; analytical recovery for sera supplemented with as much as 360 μg of cortisol per liter was 91 to 109%.

Successful endoscopic resection of adenocarcinoma arising in an esophageal inlet patch

An esophageal inlet patch is an area of heterotopic gastric mucosa in the upper esophagus. Most are asymptomatic and found incidentally. There are only 43 case reports of adenocarcinoma arising in an inlet patch, and the majority of these underwent surgical resection. We present the case of a 77-year-old man with intramucosal adenocarcinoma of the cervical esophagus, found within an esophageal inlet patch, staged T1a N0 Mx by endosonographic criteria. He was successfully treated with endoscopic therapy alone. One year following the endoscopic resection, there are no signs of residual or recurrent disease. This case highlights that adenocarcinoma can be a rare complication of an esophageal inlet patch, and that if found early, endoscopic resection appears safe and efficacious.

Influence of water chemistry and dissolved organic matter (DOM) molecular size on copper and mercury binding determined by multiresponse fluorescence quenching

The effects of water chemistry (i.e. pH and Ca(2+) concentration) dissolved organic carbon (DOC) concentration) and DOM quality (i.e. composition and molecular weight) on metal complexation were successfully investigated by a combination of tangential flow filtration, excitation-emission matrix fluorescence, parallel factor analysis (PARAFAC), and fluorescence quenching on four freshwater samples and one extracted Suwannee River fulvic acid (SRFA). Two terrestrial and one microbial humic-like components were found in this study. Despite strong correlation between the Ryan-Weber model and the multiresponse model, the latter is more appropriate for the calculation of binding parameters in multiple-ligand DOM system. Decreasing pH from 6 to 4 significantly reduced logK-Cu(2+) from 5.22±0.24 to 4.60±0.30 at pH 6 and 4, respectively (p<0.001), while the impacts of Ca(2+) and DOC were not discernible at concentrations<100ppm and<2.06ppm, respectively. For natural freshwater DOM binding, the three humic-like components had similar logK values for both metals. High molecular weight (>1kDa) DOM generally had higher logK and binding fluorophore abundance than bulk (unfractionated) and low molecular weight (<1kDa) DOM for both metals. This trend however was not always true for Hg(2+) where the binding parameters were quite variable. Overall the combined results provide evidence that binding parameters are not only affected by water chemistry, but also depend on DOM molecular weight.

Fine structural organization of the spermatheca in the cockroach, Periplaneta americana

The detailed structure of the cockroach spermatheca is described and discussed firstly as an example of an insect integumentary gland, and secondly, from the standpoint of its role in reproduction. The gland comprises a cortical rank of separate secretory units, each associated with an epithelial duct cell responsible for receiving secreted materials and transporting them through the cuticular intima lining the reproductive tract. Secretory activity is cyclic, and the probable mode of elaboration and release of secretory material is described, together with the fine structure of the markedly differing intimas associated respectively with the glandular and conducting units.

Acute and chronic toxicity of copper to the euryhaline rotifer, Brachionus plicatilis ("L" strain)

This article presents data from original research, intended for the use in the development of copper (Cu) criteria for the protection of estuarine and marine organisms and their uses in the United States. Two 48-h static-acute toxicity tests-one with and one without added food-and a 96-h static multigeneration life-cycle test (P1-F2 generations) were performed concurrently using the euryhaline rotifer Brachionus plicatilis ("L" strain) to develop a Cu acute-to-chronic ratio (ACR) for this species. Tests were performed at 15 g/L salinity, at 25°C, and the exposure concentrations of dissolved Cu were verified. Supplemental chemical analyses were performed and reported for the development of a Cu-saltwater biotic ligand model (BLM). Supplemental analyses included alkalinity, calcium, chloride, dissolved organic carbon (DOC), hardness, magnesium, potassium, sodium, and temperature. The acute toxicity test measurement end points were the dissolved Cu median lethal concentration (LC₅₀) values based on rotifer survival. The chronic measurement end points were the dissolved Cu no-observed-effect concentration (NOEC), lowest-observed-effect concentration (LOEC), EC₂₅, EC₂₀, and EC₁₀ based on the intrinsic rate of rotifer population increase (r). The 48-h LC₅₀(Fed), 48-h LC₅₀(Unfed), 96-h NOEC, 96-h LOEC, EC₂₅, EC₂₀, and EC₁₀ were 20.8, 13.4, 6.1, 10.3, 11.7, 10.9, and 8.8 μg Cu/L, respectively. The ACRs were calculated as ratios of each 48-h LC₅₀ value [fed and unfed) and each of the 96-h chronic values (ChV; geometric mean of NOEC and LOEC)], EC₁₀, EC₂₀, and EC₂₅. The ACRs ranged from 1.15 to 2.63.

The effects of salinity, pH, and dissolved organic matter on acute copper toxicity to the rotifer, Brachionus plicatilis ("L" strain)

This paper presents data from original research for use in the development of a marine biotic ligand model and, ultimately, copper criteria for the protection of estuarine and marine organisms and their uses. Ten 48-h static acute (unfed) copper toxicity tests using the euryhaline rotifer Brachionus plicatilis ("L" strain) were performed to assess the effects of salinity, pH, and dissolved organic matter (measured as dissolved organic carbon; DOC) on median lethal dissolved copper concentrations (LC50). Reconstituted and natural saltwater samples were tested at seven salinities (6, 11, 13, 15, 20, 24, and 29 g/L), over a pH range of 6.8-8.6 and a range of dissolved organic carbon of <0.5-4.1 mg C/L. Water chemistry analyses (alkalinity, calcium, chloride, DOC, hardness, magnesium, potassium, sodium, salinity, and temperature) are presented for input parameters to the biotic ligand model. In stepwise multiple regression analysis of experimental results where salinity, pH, and DOC concentrations varied, copper toxicity was significantly related only to the dissolved organic matter content (pH and salinity not statistically retained; alpha=0.05). The relationship of the 48-h dissolved copper LC50 values and dissolved organic carbon concentrations was LC50 (microg Cu/L)=27.1xDOC (mg C/L)1.25; r2=0.94.

THE STRUCTURE OF INSECT FIBRILLAR FLIGHT MUSCLE : A Study Made with Special Reference to the Membrane Systems of the Fiber

The fine structure of fibrillar flight muscle of the mature adult beetle Tenebrio molitor is described. Although the very high frequency of contraction of fibrillar muscle has previously been in part accounted for as the result of mechanical specialization of the wing-bearing segment rather than of a correspondingly high rate of motor impulse supply, the problem of the nature of the pathway by which excitation is conducted into these large fibers remained. Therefore, particular attention has been given to the disposition and relationships of the plasma membrane and sarcoplasmic reticulum in this tissue. The invading tracheoles draw with them a sheath of plasma membrane from the surface to all depths in the fiber, and it is suggested that these sheaths, together with the extensive tubular arborisations arising from them, reduce the maximum plasma membrane-to-fibril distance from the radius of the fiber to a value of less than 2 µ. The evidence presented here confirms Veratti's contention that in fibrillar muscle the "reticulum" is associated with, though entirely distinct from the fibrils. Unlike other muscles so far examined, these flight muscle fibers contain a plasma membrane reticulum only, but it is possible that elsewhere the general "sarcoplasmic reticulum" includes a component derived from the plasma membrane, likewise acting as the pathway for inward conduction of excitation. Profiles of the internalised plasma membrane in Tenebrio showing the usual triple-layered 25-25-25 A organization are frequently seen, in sections, in close association with isolated vesicles (defined by "simple" 50 A membranes) which are here considered to represent, in vestigial form, the portion of the sarcoplasmic reticulum which in other types of muscle is complex and highly developed. Such associations, in Tenebrio, between these two dissimilar elements are here termed "dyads" and the possible morphological and functional homology between these and the "triads" of other types of fiber is considered.

THE STRUCTURE OF FLIGHT MUSCLE SARCOSOMES IN THE BLOWFLY CALLIPHORA ERYTHROCEPHALA (DIPTERA)

The electron microscopic structure of sectioned indirect flight muscle fibers of the blowfly Calliphora is described. Particular attention is paid to the organization of the sarcosomes (mitochondria) of this tissue, and this description is accompanied by an account of the appearance of these bodies in negatively stained preparations. In sectioned material, it has been shown that these sarcosomes are similar to other mitochondria in the disposition of the outer and inner limiting membranes, but that the cristae, confluent with the latter, are unusually regular, and form parallel plates, containing circular fenestrations forming cylindrical channels within the matrix. Negatively stained preparations of disrupted sarcosomes reveal that both the outer limiting membrane and the cristae membranes bear large numbers of small particles, similar in appearance to those described by Fernández-Morgán and others in various mitochondria. In Calliphora, these particles consist of a sub-spherical "head" and a cylindrical "stalk," and appear to be arranged on the mitochondrial membranes either randomly distributed, or collected into circular or elongated groups. Recent suggestions concerning the nature of these submitochondrial particles are discussed, and an attempt is made to correlate the aspects of organization of Calliphora sarcosomes, revealed by conventional sectioning of the "intact" structures, and by negative staining of sarcosomal derivatives.

CELLULAR SPECIALIZATION IN THE EXCRETORY EPITHELIA OF AN INSECT, Macrosteles fascifrons STAL (HOMOPTERA)

An electron microscopic investigation of the Malpighian tubules of a leaf hopper, Macrosteles fascifrons, shows that these organs comprise three quite distinct cell types, and the structure of these and of the mid- and hindgut epithelial cells is described. In particular, a comparison is made between the organization of the basal and apical surfaces of cells in the Malpighian tubule and in the vertebrate kidney, and it is suggested that similarities between these excretory epithelia reflect functional parallels between them. While the midgut and one region of the Malpighian tubule bear a typical microvillar brush border, elsewhere in the tubule and in the hindgut the apical surface bears cytoplasmic leaflets or lamellae. The sole solid excretory material of these insects consists of the brochosomes, secreted by cells of one region of the Malpighian tubule. The structure, geometry, and development of these unusual bodies, apparently formed within specialized Golgi regions, has been investigated, and histochemical tests indicate that they contain lipid and protein components.

INNERVATION OF THE FIBRILLAR FLIGHT MUSCLE OF AN INSECT: TENEBRIO MOLITOR (COLEOPTERA)

The structure of peripheral nerves, and the organization of the myoneural junctions in flight muscle fibers of a beetle is described. The uniaxonal presynaptic nerve branches display the "tunicated" structure reported in the case of other insect nerves and the relationship between the axon and the lemnoblast folds is discussed. The synapsing nerve terminal shows many similarities with that of central and peripheral junctions of other insects and of vertebrates (e.g., the intra-axonal synaptic vesicles) but certain important differences have been noted between this region in Tenebrio flight muscle and in other insect muscles. Firstly, the axon discards the lemnoblast before the junction is established and the axon effects a circumferential synapse with the plasma membrane of the fiber, which alone shows the increased thickness often observed in both pre- and postsynaptic elements. Secondly, in addition to the synaptic vesicles within the axon are present, in the immediately adjacent sarcoplasm, great numbers of larger postsynaptic vesicles which, it is tentatively suggested, may represent the sites of storage of the enzymatic destroyer of the activating substance similarly quantized within the intra-axonal vesicles. The spatial relationship between the peripherally located junctions and the portion of the fiber plasma membrane internalized as circumtracheolar sheaths is considered, and the possible significance of this with respect to impulse conduction is discussed briefly.

THE ORGANIZATION AND INNERVATION OF THE LUMINESCENT ORGAN IN A FIREFLY, PHOTURIS PENNSYLVANICA (COLEOPTERA)

The organization of the luminescent organ of an adult firefly has been studied with the electron microscope, and particular attention has been given to the disposition of nerve terminals within the organ. The cytological structure of the cells of the tracheal system, the peripheral and terminal axons, the photocytes and the cells of the dorsal ("reflecting") layer is described. Previous observations on the peripheral course of nerve branches alongside the tracheal trunks at the level of the dorsal layer and photocyte epithelium have been confirmed, and specialised nerve endings containing axoplasmic components structurally identical with "synaptic vesicles" and "neurosecretory droplets" have been identified, not in association with the surface of the photocytes, but lying between the apposed surfaces of two components of the tracheal epithelium: the tracheal end-cell and the tracheolar cell. These cytological findings are discussed in terms of available biochemical and physiological evidence concerning the mechanism of light emission in the firefly, especially with respect to the possible role of chemical "transmitter" action in triggering a response in a luminescent effector system.

Influence of natural organic matter (NOM) quality on Cu-gill binding in the rainbow trout (Oncorhynchus mykiss)

Natural organic matter (NOM) in aquatic environments reduces metal toxicity to fish by forming metal-NOM complexes, which reduce metal bioavailability, metal-gill binding and toxicity. However, differences in the chemical composition of different types of NOM (quality) could also affect metal-NOM binding and toxicity. We predicted that Cu-gill binding would vary in trout exposed to Cu in the presence of NOM of different qualities. NOM was collected from three sources: Luther Marsh (terrigenous approximately allochthonous), Bannister Lake (nominally autochthonous), and from a local sewage treatment plant (designated Preston effluent). Excitation-emission matrix spectroscopy (EEMS) revealed that terrigenous Luther Marsh NOM was primarily humic acid-like material (74%), whereas Bannister Lake and Preston sewage effluent NOM had lower humic acid-like material but greater fulvic acid-like material (30% and 50%, respectively). The specific absorption coefficient (SAC) of Luther Marsh NOM was also much higher (SAC=37.8), consistent with its darker color, compared to more autochthonous, lightly coloured Bannister Lake (SAC=12.4) NOM, and Preston effluent NOM (SAC=9.2). At low-moderate waterborne Cu (0-2,000 nmol L(-1)), all NOM isolates reduced Cu-gill accumulation by 70-90%. Surprisingly, there were no measurable differences in Cu-gill binding amongst the three NOM treatments when fish were exposed to Cu in the low-moderate range. Only at higher Cu (>2,000 nmol L(-1)) were differences observed, where terrigenous Luther Marsh and Preston effluent NOM reduced Cu-gill binding by 40-50% more than the more autochthonous Bannister Lake NOM. Although Cu-gill binding estimates using the HydroQual BLM showed similar trends, the BLM consistently underestimated Cu-gill binding. We conclude that differences in Cu toxicity at lower-moderate Cu concentrations in the presence of different types of NOM are not necessarily related to measurable differences in Cu-gill accumulation. Rather, we suggest that differences in Cu toxicity reported in the presence of different types of NOM might be explained by direct actions of NOM on the gills, which are quality dependent.

Proton binding by hydrous ferric oxide and aluminum oxide surfaces interpreted using fully optimized continuous pKa spectra

A modified regularized least squares pKa spectrum approach is proposed to determine proton stability constants and concentrations for binding sites on hydrous ferric oxide (HFO) and aluminum oxide surfaces. Acid-base titration data are fit to a continuous binding site model for the system represented as a pKa spectrum. The modified parameter fitting method optimizes simultaneously for both smoothness of the pKa spectrum and goodness-of-fit, whereas other methods optimize for goodness-of-fit given a fixed smoothness factor. The modified method is tested with aluminum oxide and recovers values consistent with theoretical values. The regularized pKa spectrum method optimized for smoothness is applied to prepared samples of two types of HFO. The prepared HFO samples differ only in the total iron concentration of the parent solution. The resultant pKa distributions are compared to proton binding constants from MUSIC model results for crystalline iron oxides. The types of binding sites in the HFO sample are consistent with theoretical binding site stability constants for crystalline iron oxides. Overall, the prepared HFO samples have binding constants most consistent with values for lepidocrocite and goethite.

Computational and experimental approaches to studying metal interactions with microbial biofilms

The structural and compositional heterogeneity of biofilms poses unique problems in metal fate and transport. A starting point for quantitative understanding of biofilm-metal interactions is surface complexation theory, with roots in chemical equilibria and thermodynamics. This approach permits fitting of experimental data to a variety of mathematical models from which predictive parameters, such as K, may be extracted. Applications of more sophisticated fitting routines such as tableau (as in FITEQL) or spectra pK methods provide a better measure of the heterogeneity. There remain large theoretical and computational challenges, as there is ample evidence to suggest that the principle of additivity is problematic, owing to chemical interactions between individual sorbent phases within biofilms. And finally, the question of how bacterial metabolic activity is likely to influence metal uptake by biofilms adds yet another layer of complexity for future investigations.

Health care management of adults with Down syndrome

The family physician's holistic approach to patients forms the basis of good health care for adults with Down syndrome. Patients with Down syndrome are likely to have a variety of illnesses, including thyroid disease, diabetes, depression, obsessive-compulsive disorder, hearing loss, atlantoaxial subluxation and Alzheimer's disease. In addition to routine health screening, patients with Down syndrome should be screened for sleep apnea, hypothyroidism, signs and symptoms of spinal cord compression and dementia. Patients with Down syndrome may have an unusual presentation of an ordinary illness or condition, and behavior changes or a loss of function may be the only indication of medical illnesses. Plans for long-term living arrangements, estate planning and custody arrangements should be discussed with the parents or guardians. Because of improvements in health care and better education, and because more people with this condition are being raised at home, most adults with Down syndrome can expect to function well enough to live in a group home and hold a meaningful job.

Cdk5 on the brain

Mammalian brains are highly compartmentalized into groups of functionally specialized neurons. Cell migration and neurite outgrowth must be tightly orchestrated to achieve this level of organization. A small serine/threonine kinase that shows homology to cyclin-dependent kinases (Cdks) has emerged as an important regulator of neuronal migration. Cdk5, unlike other Cdks, is not regulated by cyclins, and its activity is primarily detected in postmitotic neurons in developing and adult nervous systems. This review describes work indicating that Cdk5 links extracellular signaling pathways and cytoskeletal/membrane systems to direct neuronal migration, axon growth, and possibly neurosecretion. Despite its importance, unchecked Cdk5 activity is toxic to neurons, and may underlie some of the pathologies associated with neurodegenerative disorders such as Alzheimer's disease and amyotrophic lateral sclerosis.

New concepts in acute pain therapy: preemptive analgesia

Pain, which is often inadequately treated, accompanies the more than 23 million surgical procedures performed each year and may persist long after tissue heals. Preemptive analgesia, an evolving clinical concept, involves the introduction of an analgesic regimen before the onset of noxious stimuli, with the goal of preventing sensitization of the nervous system to subsequent stimuli that could amplify pain. Surgery offers the most promising setting for preemptive analgesia because the timing of noxious stimuli is known. When adequate drug doses are administered to appropriately selected patients before surgery, intravenous opiates, local anesthetic infiltration, nerve block, subarachnoid block and epidural block offer benefits that can be observed as long as one year after surgery. The most effective preemptive analgesic regimens are those that are capable of limiting sensitization of the nervous system throughout the entire perioperative period.

Sequencing of protease inhibitor therapy: insights from an analysis of HIV phenotypic resistance in patients failing protease inhibitors

OBJECTIVE

To characterize the pattern of HIV-1 susceptibility to protease inhibitors in patients failing an initial protease inhibitor-containing regimen.

DESIGN

A cross-sectional analysis of antiretroviral susceptibility.

SETTING

HIV clinics in six metropolitan areas.

PATIENTS

Eighty-eight HIV-infected adults with HIV RNA > 400 copies/ml after > or = 6 months of antiretroviral therapy, including the use of one protease inhibitor for > or = 3 months.

MEASUREMENTS

The frequency and magnitude of decreased susceptibility, measured with a phenotypic assay using recombinant constructs, to five protease inhibitors. Decreased susceptibility was defined as > 2.5-fold increase in the 50% inhibitory concentration (IC50) compared with drug sensitive control virus.

RESULTS

At study entry, patients were being treated with nelfinavir (63%), indinavir (25%), or another protease inhibitor (11%). HIV isolates from these patients were susceptible (fold change < 2.5) to all five protease inhibitors in 18% of patients and to none in 8%. Isolates from patients receiving nelfinavir were less likely to have reduced susceptibility to other protease inhibitors than isolates from patients treated with indinavir (P < 0.001) or one of the other three agents (P < 0.001), even after adjustment for the duration of prior protease inhibitor use. Reduced susceptibility to saquinavir and amprenavir was observed significantly less frequently than for the other protease inhibitors.

CONCLUSION

The frequency of protease inhibitor cross-resistance and the magnitude of changes in susceptibility varied according to the initial protease inhibitor used in the failing treatment regimen. Significantly less protease inhibitor cross-resistance was demonstrated for isolates from patients failing a nelfinavir-containing regimen compared with those from patients receiving other protease inhibitors.

Factor analysis of the components of 12 standard test batteries, for unilateral spatial neglect, reveals that they contain a number of discrete and important clinical variables

The aim of this study was to investigate a conventional battery of tests capable of assessing the presence of the component and extent of the lesions in patients with unilateral spatial neglect. Ninety-four patients who had unilateral spatial neglect with a stroke in right hemisphere were assessed on 12 traditional neglect batteries 4 weeks after the onset. Computerized tomography was also performed to investigate the possible anatomical relationships with each neglect battery. Factor analysis showed that the tests loaded significantly on five factors. There are not only visual scanning factors but also factors of imaging, visual judgement, visual cognition and effectiveness from left hemisphere in the unilateral spatial neglect. There are high correlations between each neuropsychological test and neglect batteries. Furthermore, lesions in the paraventricular white matter were associated with clock and person drawing tasks. Lesions in the occipital lobe were associated with reading, explaining and visual counting tasks. Lesions in the temporal lobe and the posterior limb of the internal capsule were associated with line bisection tasks. It is suggested that it is possible that there are some different components in unilateral spatial neglect. Failure in some tasks may predict different lesions in terms which include localization.

A receptor presentation hypothesis for T cell help that recruits autoreactive B cells

To uncover mechanisms that drive spontaneous expansions of autoreactive B cells in systemic lupus erythematosus, we analyzed somatic mutations in variable region genes expressed by a panel of (NZB x SWR)F(1) hybridomas representing a large, spontaneously arising clone with specificity for chromatin. A single mutation within the Jkappa intron that was shared by all members of the lineage indicated that the clone emanated from a single mutated precursor cell and led to the prediction that a somatic mutation producing a functionally decisive amino acid change in the coding region would also be universally shared. Upon cloning and sequencing the corresponding germline V(H) gene, we found that two replacement somatic mutations in FR1 and CDR2 were indeed shared by all seven clone members. Surprisingly, neither mutation influenced Ab binding to chromatin; however, one of them produced a nonconservative amino acid replacement in a mutationally "cold" region of FR1 and created an immunodominant epitope for class II MHC-restricted T cells. The epitope was restricted by IA(q) (SWR), and the SWR MHC locus is associated with systemic lupus erythematosus in (NZB x SWR)F(1) mice. These, and related findings, provoke the hypothesis that autoreactive B cells may be recruited by a "receptor presentation" mechanism involving cognate interactions between T cells and somatically generated V region peptides that are self-presented by B cells.

Cell surface electrochemical heterogeneity of the Fe(III)-reducing bacteria Shewanella putrefaciens

Acid-base titration experiments and electrostatic force microscopy (EFM) were used to investigate the cell surface electrochemical heterogeneity of the Fe(III)-reducing bacteria, Shewanella putrefaciens. The acid-base titrations extended from pH 4 to 10, and the titration data were fit using a linear programming pKa spectrum approach. Overall, a five-site model accounted for the observed titration behavior with the most acidic sites corresponding to carboxylic groups and phosphodiester groups, intermediate sites phosphoryl groups, and two basic sites equivalent to amine or hydroxyl groups. The pH for the point of zero charge on the bacteria was 5.4. In EFM images of cells rinsed in solutions at pH 4.0, 7.0, and 8.0, a pronounced increase in small (< or = 100 nm diameter) high contrast patches was observed on the cells with increasing pH. The pH dependence of EFM image contrast paralleled the pattern of cell surface charge development inferred from the titration experiments; however, quantitative analysis of high contrast regions in the EFM images yielded lower surface charge values than those anticipated from the titration data. For example at pH 7, the calculated surface charge of high contrast regions in EFM images of the bacterial cells was -0.23 microC/cm2 versus -20.0 microC/cm2 based on the titration curve. The differences in surface charge estimates between the EFM images and titration data are consistent not only with charge development throughout the entire volume of the bacterial cell wall (i.e., in association with functional groups that are not directly exposed at the cell surface) but also with the presence of a thin structural layer of water containing charge-compensating counterions. In combination, the pKa spectra and EFM data demonstrate that a particularly high degree of electrochemical heterogeneity exists within the cell wall and at the cell surface of S. putrefaciens.

Autosomal dominant inheritance of prostate cancer: a confirmatory study

OBJECTIVES

To confirm, in a study of a large, independent cohort of families with prostate cancer, the findings of three segregation analyses that have suggested the existence of an inherited form of prostate cancer with an autosomal dominant inheritance mode.

METHODS

Between January 1991 and December 1993, 1199 pedigrees were ascertained through single, unrelated, prostate cancer probands who presented for radical prostatectomy at the Division of Urologic Surgery, Washington University Medical Center in St. Louis, Missouri. Maximum likelihood segregation analysis was used to test specifically for mendelian inheritance of prostate cancer.

RESULTS

Segregation analyses revealed that the familial aggregation of prostate cancer can be best explained by the autosomal dominant inheritance of a rare (q = 0.0037) high-risk allele. According to the best-fitting autosomal dominant model, 97% of all carriers will be affected by 85 years of age compared with 10% of noncarriers. Furthermore, the autosomal dominant model predicts that the high-risk allele accounts for a large proportion (65%) of all patients diagnosed with prostate cancer before 56 years of age. However, of all prostate cancer cases, a relatively small proportion is inherited (8% by 85 years old).

CONCLUSIONS

These results are in agreement with earlier reports of segregation analyses of prostate cancer and strengthen the evidence that prostate cancer is inherited in a mendelian fashion within a subset of families.

Induction of DNA replication in adult rat neurons by deregulation of the retinoblastoma/E2F G1 cell cycle pathway

In adult organisms, a range of proliferative capacities are exhibited by different cell types. Stem cell populations in many tissues readily enter the cell cycle when presented with serum growth factors or other proliferative cues, whereas "terminally" postmitotic cells, such as cardiac myocytes and neurons, fail to do so. Although they rarely show evidence of a proliferative capacity in vivo, there is accumulating evidence to suggest that DNA synthesis can be triggered in postmitotic cells. We now show that cultured adult rat sensory neurons can replicate DNA in response to ectopic expression of E2F1 or E2F2 and that this is augmented by expression of cyclin-dependent kinase activities. We also find that addition of serum and laminin inhibits the E2F-induced S-phase in neurons but not in nonneuronal cells in the same cultures. We conclude that, although terminally differentiated neurons possess the capacity to reinitiate DNA replication in response to G1 regulatory activities, they fail to do so in the presence of signals that do not inhibit S-phase in other cell types in the same cultures. This suggests the existence of cell type-specific inhibitory pathways induced by these signals.

NUDEL is a novel Cdk5 substrate that associates with LIS1 and cytoplasmic dynein

Disruption of one allele of the LIS1 gene causes a severe developmental brain abnormality, type I lissencephaly. In Aspergillus nidulans, the LIS1 homolog, NUDF, and cytoplasmic dynein are genetically linked and regulate nuclear movements during hyphal growth. Recently, we demonstrated that mammalian LIS1 regulates dynein functions. Here we characterize NUDEL, a novel LIS1-interacting protein with sequence homology to gene products also implicated in nuclear distribution in fungi. Like LIS1, NUDEL is robustly expressed in brain, enriched at centrosomes and neuronal growth cones, and interacts with cytoplasmic dynein. Furthermore, NUDEL is a substrate of Cdk5, a kinase known to be critical during neuronal migration. Inhibition of Cdk5 modifies NUDEL distribution in neurons and affects neuritic morphology. Our findings point to cross-talk between two prominent pathways that regulate neuronal migration.

Short-wave infrared transfer radiometer for the calibration of the moderate-resolution imaging spectrometer and the advanced spaceborne thermal emission and reflection radiometer

A short-wave infrared (700-2500-nm) radiometer has been designed and built to calibrate and cross calibrate spherical-integrating sources used in the calibration of satellite sensors residing on NASA's Earth Observing System platforms. We describe the design, predicted and measured performance, and calibration of the transfer radiometer.

Regulation of cytoplasmic dynein behaviour and microtubule organization by mammalian Lis1

Whereas total loss of Lis1 is lethal, disruption of one allele of the Lis1 gene results in brain abnormalities, indicating that developing neurons are particularly sensitive to a reduction in Lis1 dosage. Here we show that Lis1 is enriched in neurons relative to levels in other cell types, and that Lis1 interacts with the microtubule motor cytoplasmic dynein. Production of more Lis1 in non-neuronal cells increases retrograde movement of cytoplasmic dynein and leads to peripheral accumulation of microtubules. These changes may reflect neuron-like dynein behaviours induced by abundant Lis1. Lis1 deficiency produces the opposite phenotype. Our results indicate that abundance of Lis1 in neurons may stimulate specific dynein functions that function in neuronal migration and axon growth.

Concordance of clinical findings and clinical judgment in the diagnosis of streptococcal pharyngitis

OBJECTIVE

It is uncertain how reliably clinicians apply clinical predictors of group A beta hemolytic streptococcal pharyngitis (GABHSP) to form a clinical impression, and how reliably this impression predicts culture results. The objective was to study clinician accuracy in diagnosing GABHSP.

METHODS

This was a prospective cohort study, conducted at an urgent care center of a major university. A convenience sample of 218 patients, aged 9-83 years, presenting with sore throat, was enrolled. Symptoms and signs of pharyngitis were documented on a standardized form; the likelihood of GABHSP was plotted on a visual analog scale; and throat culture was obtained. A comparison was then made between the clinical impression on presentation and the throat culture result.

RESULTS

Throat cultures were positive for GABHSP in 41 patients (19%). The probability of GABHSP was related to node size and tenderness, tonsillar exudate and hypertrophy, and pharyngeal erythema (p<0.05); but not throat soreness, degree of fever, or cough. A strong clinical impression of GABHSP (>50% on the visual analog scale) was associated with tonsillar exudate and hypertrophy, tender nodes, and pharyngeal erythema. Together, these four predictors had a sensitivity of 71%, a specificity of 77%, and a positive predictive value of 46%.

CONCLUSIONS

Clinicians in this study based their impression of GABHSP on the most reliable symptoms and signs. While a strong clinical suspicion of GABHSP predicted a greater probability of positive culture, the clinicians consistently overestimated the probability of GABHSP. Symptoms and signs predict GABHSP unreliably when used alone; they are helpful in modifying estimates of disease probability to facilitate optimal use of laboratory tests and antibiotics.

Music therapy assessment in school settings: a preliminary investigation

The present investigation was undertaken in response to music therapists working in school settings for information relating to the availability of music therapy assessments and the feasibility of standardizing an assessment instrument for music therapists to use in school settings. Five research questions were identified, and the music therapy literature was surveyed to compile responses to those questions. Three different online data bases (ERIC, PsycINFO, and Article 1st) were used, covering articles published between 1980 and 1997. Individual hand searches were done of the Arts in Psychotherapy, Journal of Music Therapy, Journal of Research in Music Education, Journal of the International Association of Music for the Handicapped, Music Therapy and Music Therapy Perspectives. The questions and responses were as follows: 1. Which music-based assessment tools are being used with children with disabilities? Little commonality in assessment tools being used by music therapists and researchers was discovered. Of the total 41 studies, 20 (49%) reported using a "named" or "titled" assessment tool, and in the remaining 51% of studies, the authors reported using an untitled, and usually experimenter-designed, original assessment tool. 2. Have certain assessments been used in more than one study? Very limited replication of existing assessments was found. Of the 16 "named" assessments, only 3 were found to be used in more than one research study. 3. Are the actual assessments published along with the articles describing their use? Only 3 of the 20 studies using named assessments were published along with the journal article. Of the remaining 21 studies using original, experimenter-designed assessment tools, only 6 (28%) had the assessment instrument published with the article. 4. What is the primary purpose for using the assessment? Six primary purposes emerged from the review of the literature: to compare with data obtained from other assessment measures or from other populations (39%), as a baseline or pretest measure (29%), to determine eligibility for services or the receipt of treatment (12%), to determine the psychometric properties of the assessment (7%), suitability of the instrument for the given population (7%), and the identification of musical preferences (5%). 5. What are the musical or nonmusic elements being assessed? Musical elements were: music perception (37%), musical aptitude (29%), musical preferences (12%), and attention to/enjoyment of music (2%). Nonmusical behaviors/responses were: self-expression (10%), motor responses (10%), behavioral responses (7%), cognitive development (2%), and acts of communication (2%). 6. What subject populations are being assessed? Subject populations were: children with developmental disabilities/mental retardation (44%), children with autism (10%), children with hearing impairments (17%), "psychiatric" clients or emotionally disturbed (22%), individuals described as "handicapped" (5%), individuals with physical disabilities (2%), and a student with a speech impairment (2%). Nondisabled individuals were also included in 12 of the aforementioned studies.

Translational control of ribosomal protein L4 mRNA is required for rapid neurite regeneration

Under some circumstances neurons can be primed to rapidly regenerate injured neuritic processes independent of new gene expression. Such transcription-independent neurite extension occurs in adult rat sensory neurons cultured after sciatic nerve crush and in NGF-differentiated PC12 cells whose neurites have been mechanically sheared. In the PC12 cells, neurite regeneration occurs by means of translational control of mRNAs which were transcribed prior to neurite injury. The survival of such translationally regulated mRNAs is relatively short in the differentiated PC12 cells (< or =10 h). By subtractive hybridization, we have isolated a short-lived mRNA from differentiated PC12 cells. This mRNA, which encodes the ribosomal protein L4, is translationally regulated during neurite regeneration in PC12 cells. Antisense oligonucleotides to L4 mRNA inhibit neurite regeneration from the differentiated PC12 cells as well as axonal elongation from conditioned sensory neurons, indicating that ongoing translation of L4 mRNA is needed for these forms of rapid transcription-independent neurite growth. Taken together, these data point to the importance of translational regulation of existing neuronal mRNAs in the regenerative responses to neuronal injury. Although there are other examples of neuronal translational control, there are no other known neuronal proteins whose levels are regulated predominantly by translational rather than transcriptional control.

Apraxia and cerebral haemorrhage: the relationship between haematoma volume and prognosis

In this study, we examined twenty-five patients with left putaminal haemorrhage to investigate the relations between ideational apraxia (IA) and intracerebral haemorrhage. Apraxias were determined at 1 and 6 months after the stroke onset. Extension and volume of haematoma were examined with CT scan within 2 days of stroke onset. IA was present in 10 cases at 1 month and disappeared in 6 cases (transient IA) and persisted in 4 cases(persisted IA) at 6 months from the onset. Although the haematoma volume related to the existence of IA, there was no significant difference between transient and persistent IA. All three patients with the haematoma volume larger than 40 ml in the transient IA group were younger than 50 years old. All cases with persistent IA were older than 50 years old. Consequently, the existence of IA seems to be partially dependent on the haematoma volume which may cause the organic damage of subcortical white matter. However, patient's age is also important to determine the prognosis of IA. This maybe related to the nature of the haemorrhage and the mode of the onset. These factors remain to be determined.

Blunt splenic injuries: dedicated trauma surgeons can achieve a high rate of nonoperative success in patients of all ages

BACKGROUND

Selective nonoperative management (NOM) of blunt splenic injuries is becoming a more prevalent practice. Inclusion criteria for NOM, which have been a source of controversy, continue to evolve. Age > or = 55 years has been proposed as a predictor for failure of and even a contraindication to NOM of blunt splenic trauma. Additionally, the high rate of NOM in children (up to 79%) has been attributed to their management by pediatric surgeons. We evaluated our experience with NOM of blunt splenic injury with special attention to these age groups.

METHODS

By using our trauma registry, all patients with blunt splenic injuries (documented by computed tomography, operative findings, or both) cared for over a 36-month period, at a single American College of Surgeons verified Level I trauma center were reviewed. Detailed chart reviews were performed to examine admission demographics, laboratory data, radiologic findings, outcome measures, and patient management strategy. All patients were managed by nonpediatric trauma surgeons. We then compared our adult data with that in the recent literature and our pediatric data with that of the National Pediatric Trauma Registry over the same time period.

RESULTS

We identified 251 consecutive patients with blunt splenic injuries. Eighteen patients who expired in the immediate postinjury period were excluded from statistical evaluation. No deaths occurred as a result of splenic injury. Of the remaining 233 patients, 73 patients (31%) required early celiotomy, 160 patients (69%) were selected for NOM, with 151 patients (94%) being successfully managed without operation. Blunt splenic injury occurred in 23 patients age 55 years or older. Eighteen patients (78%) were selected for NOM and 17 patients (94%) were successfully treated without operation. Blunt splenic injury occurred in 35 patients less than 16 years of age. Thirty-two patients (91%) were selected for NOM. Thirty-one patients (89% of all pediatric patients) were successfully treated without operation.

CONCLUSION

Age > or = 55 years is not a contraindication to nonoperative management of blunt splenic injuries. Children with blunt splenic injuries can be successfully managed nonoperatively by nonpediatric trauma surgeons.

Sequence heterogeneity in Ig kappa transcripts from single B lymphocytes

Individually amplified kappa cDNA molecules from single B lymphocytes revealed sequence heterogeneity and aberrantly spliced products. The nature and frequency of the base changes and their absence from similarly amplified beta2 microglobulin transcripts indicate that they were not derived by Taq polymerase misincorporations or by a general infidelity in RNA polymerase. The trinucleotide sequences in which the base changes occurred are disfavored targets of the somatic hypermutation mechanism that modifies antibody variable (V) region genes during immunity. Taken together with the observation that the transcript alterations were absent from the kappa Ig gene, this suggests that somatic mutations were acquired by the kappa gene and rapidly repaired following limited transcription. Preferential repair of mutations located in specific trinucleotide contexts could be the basis for some of the microsequence-specific bias in mutation frequencies observed in antibody V region genes.

Quality-of-life outcomes for men with prostate carcinoma detected by screening

BACKGROUND

There is limited information on outcomes of prostate carcinoma treatments given to screened patient populations for whom cancer is usually detected at an earlier stage.

METHODS

The authors conducted a cross-sectional evaluation of quality-of-life outcomes for men with prostate carcinoma detected in screening studies at a university center. Of 2234 men diagnosed with prostate carcinoma between 1989 and 1997, 74% responded to the questionnaire. Primary management included radical prostatectomy (76%), radiotherapy (11%), observation (7%), hormonal therapy (4%), and cryoablation (2%). Main outcome measures included validated measurements of quality of life, urinary and sexual functioning, and bother (36-item RAND Health Survey, UCLA Prostate Cancer Index).

RESULTS

After controlling for demographic factors, differences among treatment groups were found for all general quality-of-life outcomes, with increased impairment in men who underwent hormonal therapy (all P values <0.05). Urinary and sexual function and bother were also significantly related to treatment. However, among men followed for > or =12 months, only 9% reported a moderate or major problem with urinary control. Sexual functioning was a moderate or major problem following treatment for 58% treated with prostatectomy, 48% treated with radiotherapy, 64% treated with hormonal therapy, 45% treated with cryoablation, and 30% managed with observation. Approximately one-third of the men younger than 70 years who underwent radical prostatectomy maintained adequate sexual functioning posttreatment.

CONCLUSIONS

Up to 6 years after diagnosis, the majority of men with prostate carcinoma detected by screening were bothered by their current sexual function, regardless of treatment. In contrast, most men were not bothered by their current urinary function.

Mycobacterium terrae: case reports, literature review, and in vitro antibiotic susceptibility testing

Mycobacterium terrae infection can cause debilitating disease that is relatively resistant to antibiotic therapy. Two cases are presented, and data from an additional 52 reports from the literature are reviewed. Tenosynovitis of the upper extremity, often following trauma, was the most commonly reported presentation (59% of cases), with pulmonary disease occurring in an additional 26% of cases. Underlying medical problems were absent (44%) or not reported (28%) in 72% of the cases. One-half of the patients with upper extremity tenosynovitis were treated with local or systemic corticosteroids, before microbiological identification. Only one-half of the patients with tenosynovitis who were followed up for 6 months had clinical improvement or were cured. The other one-half of the patients required repeated debridement, tendon extirpation, or amputation. The best antimicrobial therapy for M. terrae infection is unknown but might include a macrolide antibiotic plus ethambutol and one other effective drug for at least 12 months after clinical response. Parenteral treatment with an aminoglycoside and surgery may be useful in selected cases.

Pain and morbidity of transrectal ultrasound guided prostate biopsy: a prospective randomized trial of 6 versus 12 cores

PURPOSE

An increasing number of studies suggest that 6-sector transrectal ultrasound guided biopsy of the prostate provides insufficient material to detect all clinically important prostate cancers and more cores may improve detection rates. We performed a prospective, randomized study to determine the effect of increasing the number of cores from 6 to 12 on pain and other morbidity associated with the biopsy procedure.

MATERIALS AND METHODS

A total of 160 men (44 black, 28%) with a mean age plus or minus standard deviation of 65+/-8 years who had serum prostate specific antigen between 2.5 and 20.0 ng./ml. and/or digital rectal examination findings suspicious for cancer were prospectively randomized to undergo 6 or 12-core biopsy. Patients completed a self-administered questionnaire addressing pain and other morbidity before, and immediately and 2 and 4 weeks after biopsy.

RESULTS

There was no difference between groups in mean pain scale with time for abdominal and rectal pain. For probe insertion, needle insertion and overall pain there was a significant increase in pain recalled at 2 which persisted at 4 weeks compared to immediately after biopsy. However, there was no difference for these 3 post-biopsy pain measures between the 6 and 12-core groups. In the 12-core group there was a statistically significant increase in hematochezia and hematospermia (24% versus 10%, p = 0.04 and 89% versus 71%, p = 0.01, respectively) but no significant difference between groups reporting morbidity as a moderate or major problem. There was no significant change in International Prostate Symptom Score, fever or hospitalization in the 12-core group.

CONCLUSIONS

The 12-core prostate biopsy procedure is generally well tolerated and can be safely performed with no significant difference in pain or morbidity compared to the 6-core procedure.

Music Therapy in School Settings: Current Practice

The practice of music therapy in school settings was the focus of this study. Survey forms were mailed to 244 NAMT members who indicated school setting as their place of employment. A total of 190 forms were received, 138 of which fit the qualifications for inclusion and were included in the data summaries. Greater numbers of respondents lived in Texas (21), New York (17), and Michigan (11), and were employed full-time (60&percent;). Employers were more typically school systems (53&percent;) for the highest percentage of full-time respondents (80&percent;), and self-employers (25&percent;) for the highest percentage of part-time respondents (80&percent;). A considerably higher percentage of time was spent each week in direct service delivery (62&percent;) than in consultation (13&percent;), travel (18&percent;), documentation (11&percent;), or preparation (14&percent;). Over 40&percent; of the respondents had been music therapists for more than 8 years, but not necessarily in their current positions. Almost 40&percent; needed a valid teaching certificate for employment, while over 50&percent; currently held one. Respondents most frequently worked with persons who were developmentally disabled (80&percent;). The impact of employer and the inclusion movement on professional practice issues was discussed, as were possible trends in the practice of music therapy in school settings.

Understanding external controls over the commercial introduction of engineered human tissues. Assessing regulatory and liability issues

Emerging biomedical technologies present a new order of magnitude of complexity in their interactions with human patients. As such, they challenge established processes for protecting patients and the public health, while testing the capacity of those processes to ensure timely access to beneficial therapies--especially those representing significant advances over existing therapies. This article reviews the Food and Drug Administration (FDA) regulatory process--including the classification of medical products, the marketing review and approval pathways, and the 1997 FDA Modernization Act--and discusses other legal and policy considerations relevant to engineered tissues.

Changes in family functioning for stroke rehabilitation patients and their families

This study charted changes over time in the family functioning of a group of stroke rehabilitation patients and their families. Participants were 60 12-month stroke survivors who had undergone an inpatient rehabilitation programme, 46 spouses, and 25 other family members. Participants were assessed at the time of admission to and discharge from rehabilitation, and 6 and 12 months after discharge. The study was undertaken in the rehabilitation unit at Repatriation General Hospital, in Adelaide, South Australia. Family functioning was assessed using the McMaster Family Assessment Device, and functional outcome was monitored with the competence scale of the Australian ADL Index. Longitudinal change in family functioning was observed in problem solving, family communication, role definition, behaviour control, and affective involvement. There were no significant differences between the family functioning ratings provided by patients and their spouses. It is important that consideration be given to means by which the increase in family dysfunction following stroke can be addressed.

Potency, continence and complication rates in 1,870 consecutive radical retropubic prostatectomies

PURPOSE

We update results in a series of consecutive patients treated with anatomic radical retropubic prostatectomy regarding recovery of erections, urinary continence and postoperative complications.

MATERIALS AND METHODS

One surgeon performed anatomic radical retropubic prostatectomy on 1,870 men, using the nerve sparing modification when feasible. We evaluated recovery of erections and urinary continence in men followed for a minimum of 18 months. Patients who were not reliably potent before surgery, did not undergo a nerve sparing procedure, or received hormonal therapy or postoperative adjuvant radiotherapy were excluded from the analysis of potency rates but not of continence rates. Other postoperative complications were evaluated for the entire patient population.

RESULTS

Recovery of erections occurred in 68% of preoperatively potent men treated with bilateral (543 of 798) and 47% treated with unilateral (28 of 60) nerve sparing surgery. Recovery of erections was more likely with bilateral than with unilateral nerve sparing surgery in patients less than 70 years old (71 versus 48%, p<0.001) compared with patients with age 70 years old or older (48 versus 40%, p = 0.6). Recovery of urinary continence occurred in 92% (1,223 of 1,325 men) and was associated with younger age (p<0.0001) but not with tumor stage (p = 0.2) or nerve sparing surgery (p = 0.3). Postoperative complications occurred in 10% of patients overall and were associated with older age (p<0.002) but the incidence declined significantly with increasing experience of the surgeon (p<0.0001). There was no operative mortality.

CONCLUSIONS

Anatomic radical retropubic prostatectomy with the nerve sparing modification can be performed with favorable results in preserving potency and urinary continence. Better results are achieved in young men with organ confined cancer. Other complications can be reduced with increasing surgeon experience.