Inbred SJL mice recapitulate human resistance to Cryptococcus infection due to differential immune activation

IMPORTANCE

Cryptococcosis studies often utilize the common C57BL/6J mouse model. Unfortunately, infection in these mice fails to replicate the basic course of human disease, particularly hampering immunological studies. This work demonstrates that SJL/J mice can recapitulate human infection better than other mouse strains. The immunological response to Cryptococcus infection in SJL/J mice was markedly different from C57BL/6J and much more productive in combating this infection. Characterization of infected mice demonstrated strain-specific genetic linkage and differential regulation of multiple important immune-relevant genes in response to Cryptococcus infection. While our results validate many of the previously identified immunological features of cryptococcosis, we also demonstrate limitations from previous mouse models as they may be less translatable to human disease. We concluded that SJL/J mice more faithfully recapitulate human cryptococcosis serving as an exciting new animal model for immunological and genetic studies.

Foliar functional and genetic variation in a keystone Hawaiian tree species estimated through spectroscopy

Imaging spectroscopy has the potential to map closely related plant taxa at landscape scales. Although spectral investigations at the leaf and canopy levels have revealed relationships between phylogeny and reflectance, understanding how spectra differ across, and are inherited from, genotypes of a single species has received less attention. We used a common-garden population of four varieties of the keystone canopy tree, Metrosideros polymorpha, from Hawaii Island and four F1-hybrid genotypes derived from controlled crosses to determine if reflectance spectra discriminate sympatric, conspecific varieties of this species and their hybrids. With a single exception, pairwise comparisons of leaf reflectance patterns successfully distinguished varieties of M. polymorpha on Hawaii Island as well as populations of the same variety from different islands. Further, spectral variability within a single variety from Hawaii Island and the older island of Oahu was greater than that observed among the four varieties on Hawaii Island. F1 hybrids most frequently displayed leaf spectral patterns intermediate to those of their parent taxa. Spectral reflectance patterns distinguished each of two of the hybrid genotypes from one of their parent varieties, indicating that classifying hybrids may be possible, particularly if sample sizes are increased. This work quantifies a baseline in spectral variability for an endemic Hawaiian tree species and advances the use of imaging spectroscopy in biodiversity studies at the genetic level.

Airborne laser-guided imaging spectroscopy to map forest trait diversity and guide conservation

Functional biogeography may bridge a gap between field-based biodiversity information and satellite-based Earth system studies, thereby supporting conservation plans to protect more species and their contributions to ecosystem functioning. We used airborne laser-guided imaging spectroscopy with environmental modeling to derive large-scale, multivariate forest canopy functional trait maps of the Peruvian Andes-to-Amazon biodiversity hotspot. Seven mapped canopy traits revealed functional variation in a geospatial pattern explained by geology, topography, hydrology, and climate. Clustering of canopy traits yielded a map of forest beta functional diversity for land-use analysis. Up to 53% of each mapped, functionally distinct forest presents an opportunity for new conservation action. Mapping functional diversity advances our understanding of the biosphere to conserve more biodiversity in the face of land use and climate change.

A Systematic Review Examining the Oral Health Status of Persons with Dementia

While the oral health of persons with dementia has been shown to be poor, no systematic reviews have been published that examined the topic in depth, including participants with dementia representing the full spectrum of disease severity, and evaluating a broad scope of oral health assessments. The aim of this study was to conduct a current literature review to fill this gap in knowledge. A systematic search of 5 databases (CINAHL, PubMed, EMBASE, Scopus, and ISI Web of Science) was conducted to identify all relevant studies published up to May 2016. There were no exclusions related to study type, severity of dementia, dentate status, or living arrangements. Results were reported descriptively and summarized. Meta-analyses were performed where possible and reported as mean difference (MD) or standardized mean difference (SMD), with a 95% confidence interval (CI). Twenty-eight studies were identified. Assessments were conducted of tooth status, active dental caries, hygiene (plaque/calculus) of natural and artificial teeth, periodontal diseases, denture status (retention, stability, denture-related mucosal lesions), and oral health-related quality of life. Across all evaluations, persons with dementia generally had scores/results suggestive of poor oral health. In meta-analyses, compared with persons without dementia, those with dementia had a significantly fewer number of teeth (MD, -1.52; 95% CI, -0.2.52 to -0.52; P = 0.003; n = 13 studies), more carious teeth (SMD, 0.29; 95% CI, 0.03 to 0.48; P = 0.028; n = 9), significantly worse oral hygiene evaluated using a broad range of assessment tools (SMD, 0.88; 95% CI, 0.57 to 1.19, P < 0.0001; n = 7), and significantly poorer periodontal health (SMD, 0.38; 95% CI, 0.06 to 0.70; P = 0.02; n = 6 studies). The oral health status of persons with mild to severe forms of dementia, who were living in both the community and residential care facilities, was found to be poor across a broad range of dental assessments. Knowledge Transfer Statement: The results of this study define the scope of oral issues and quantify the degree of impairment in individuals with dementia, evaluated using a variety of oral health measures. The results revealed that poor oral health is associated with dementia.

Landscape-scale variation in plant community composition of an African savanna from airborne species mapping

Information on landscape-scale patterns in species distributions and community types is vital for ecological science and effective conservation assessment and planning. However, detailed maps of plant community structure at landscape scales seldom exist due to the inability of field-based inventories to map a sufficient number of individuals over large areas. The Carnegie Airborne Observatory (CAO) collected hyperspectral and lidar data over Kruger National Park, South Africa, and these data were used to remotely identify > 500 000 tree and shrub crowns over a 144-km2 landscape using stacked support vector machines. Maps of community compositional variation were produced by ordination and clustering, and the importance of hillslope-scale topo-edaphic variation in shaping community structure was evaluated with redundancy analysis. This remote species identification approach revealed spatially complex patterns in woody plant communities throughout the landscape that could not be directly observed using field-based methods alone. We estimated that topo-edaphic variables representing catenal sequences explained 21% of species compositional variation, while we also uncovered important community patterns that were unrelated to catenas, indicating a large role for other soil-related factors in shaping the savanna community. Our results demonstrate the ability of airborne species identification techniques to map biodiversity for the evaluation of ecological controls on community composition over large landscapes.

Effect of dietary organic microminerals on starter pig performance, tissue mineral concentrations, and liver and plasma enzyme activities

Weanling pigs (n = 160) were used to evaluate dietary essential microminerals (Cu, Fe, Mn, Se, and Zn) on performance, tissue minerals, and liver and plasma enzymatic activities during a 35-d postweaning period. A randomized complete block design with 5 treatments and 8 replicates was used in this study. Organic microminerals were added to complex nursery diets at 0 (basal), 50, 100, or 150% of the requirements of microminerals listed by the 1998 NRC. A fifth treatment contained inorganic microminerals at 100% NRC and served as the positive control. Pigs were bled at intervals with hemoglobin (Hb), hematocrit (Hct), glutathione peroxidase, and ceruloplasmin activities determined. Six pigs at weaning and 1 pig per pen at d 35 were killed, and the liver, heart, loin, kidney, pancreas, and the frontal lobe of the brain were collected for micromineral analysis. The liver was frozen in liquid N for determination of enzymatic activities. The analyzed innate microminerals in the basal diet met the NRC requirement for Cu and Mn but not Fe, Se, and Zn. Performance was not affected from 0 to 10 d postweaning, but when microminerals were added to diets, ADG, ADFI, and G:F improved (P < 0.01) from 10 to 35 d and for the overall 35-d period. Pigs fed the basal diet exhibited parakeratosis-like skin lesions, whereas those fed the supplemental microminerals did not. This skin condition was corrected after a diet with the added microminerals was fed. When the basal diet was fed, Hb and Hct declined, but supplemental microminerals increased Hb and Hct values. Liver catalase activity increased (P < 0.01) when microminerals were fed. The Mn superoxide dismutase activity tended to decline quadratically (P = 0.06) when supplemental microminerals were fed above that of the basal diet. Liver plasma glutathione peroxidase activities were greater (P < 0.01) when dietary organic and inorganic micromineral were fed. Liver concentrations of microminerals increased linearly (P < 0.01) as dietary microminerals increased, indicating that the liver was the primary storage organ. Micromineral tissue concentrations were least in pigs fed the basal diet and increased (quadratic, P < 0.01) to the 50% level of organic microminerals in the various tissues collected. The results indicated that innate microminerals, Cu and Mn, from a complex nursery diet may meet the micromineral needs of the weaned pig, but the need for Fe, Se, or Zn was not met by the basal diet.

Effect of x-ray irradiation on reducing the risk of listeriosis in ready-to-eat vacuum-packaged smoked mullet

Listeria monocytogenes can pose a serious threat in several areas of the nation's food supply including ready-to-eat seafood products. Use of irradiation processing can potentially reduce the risk of listeriosis caused by consumption of ready-to-eat seafood products. This study measured the effect of X-ray irradiation on reducing the population of L. monocytogenes on ready-to-eat, vacuum-packaged smoked mullet. Smoked mullet were inoculated with a five-strain mixture of L. monocytogenes (10(4) CFU/g), vacuum packaged, and irradiated (0, 0.5, 1.0, 1.5, and 2.0 kGy). The packaged fish were then stored at 3 and 10 degrees C for 90 and 17 days, respectively. Radiation doses of 0.5, 1.0, and 1.5 kGy reduced the initial population of L. monocytogenes by 1.1, 1.6, and 2.1 log CFU/g, respectively. The 2.0-kGy dose reduced L. monocytogenes to undetectable levels with no recovery growth at either temperature. Compared to the control, irradiation at 1.5 kGy demonstrated 1.0 and 1.7 log CFU/g less growth at 3 degrees C after 60 days and 10 degrees C after 17 days, respectively. Sensory flavor analysis was conducted to determine if a difference existed between irradiated samples. Panelists indicated that there were no differences among treated and untreated samples. An X-ray dose of 2 kGy effectively eliminated 10(4) CFU/g L. monocytogenes on smoked mullet without changing sensory quality.

Plasmodium permeomics: membrane transport proteins in the malaria parasite

Membrane transport proteins are integral membrane proteins that mediate the passage across the membrane bilayer of specific molecules and/or ions. Such proteins serve a diverse range of physiological roles, mediating the uptake of nutrients into cells, the removal of metabolic wastes and xenobiotics (including drugs), and the generation and maintenance of transmembrane electrochemical gradients. In this chapter we review the present state of knowledge of the membrane transport mechanisms underlying the cell physiology of the intraerythrocytic malaria parasite and its host cell, considering in particular physiological measurements on the parasite and parasitized erythrocyte, the annotation of transport proteins in the Plasmodium genome, and molecular methods used to analyze transport protein function.

Docosahexaenoic, arachidonic, palmitic, and oleic acids are differentially esterified into phospholipids of frog retina

Docosahexaenoic acid (22:6n-3) is highly enriched in the retina. To determine if retinal cells take up and metabolize fatty acids in a specific manner, retinas from Rana pipiens were incubated for 3 h with an equimolar mixture of tritiated 22:6n-3, arachidonic acid (20:4n-6), palmitic acid, and oleic acid. The radiolabeling of retinal lipids was determined and compared to the endogenous fatty acid content of the lipids. The results showed that in most, but not all, cases, the relative labeling with the four precursor fatty acids was similar to their relative abundance in each glycerolipid. Thus, during retinal glycerolipid synthesis, either through de novo or acyl exchange reactions, fatty acids are incorporated in proportions reflecting their steady-state mass levels. Since other studies with labeled glycerol have shown greater differences between early labeling patterns and molecular species mass, the final incorporation we report may be due primarily to acyl exchange reactions.

Computer measurement of oral movement in swallowing

This article describes a computer program that automatically detects and tracks small metal markers affixed to a subject's tongue and teeth in fluoroscopic image sequences of swallowing. The program, written in Microsoft Visual C++ using Windows NT 4.0 and the SAVANT imaging toolkit, involves marker detection and marker tracking. Marker detection is done by template matching. A generic marker template was designed by extracting the grayvalues of pixels within an imaged marker. Template matching with a weighted center-of-mass calculation determined marker location with subpixel accuracy. Marker tracking employed a nearest-neighbor algorithm since (a) the movement of each marker was less than the distance between any two markers and (b) marker trajectories did not overlap. Effects of head motion were attenuated by computing tongue trajectories with respect to a constant frame of reference given by reference markers on the maxillary teeth. Motions were converted from pixels/frame to millimeters/second using a calibration ring secured to the subject's neck. Results for several image sequences showed that our program performs very well in terms of marker detection and trajectory determination. Comparison of automatic and manual tracking of the same image sequences indicated a high degree of correspondence. Automatic tracking of oral movement by computer is a useful tool in kinematic studies of swallowing.

Oropharyngeal dysphagia in esophageal cancer before and after transhiatal esophagectomy

Although dysphagia is the predominant symptom of esophageal cancer, the nature of the swallowing deficit remains unclear, particularly regarding an oropharyngeal motor component. The present study examined the oropharyngeal swallow in patients with esophageal cancer before and following transhiatal esophagectomy. Videofluoroscopic data were obtained from ten patients with esophageal cancer before and following transhiatal esophagectomy as they swallowed 2-, 5-, and 10-cc aliquots of liquid and puree, and 0.5 and 1 tsp of solid. Each swallow was rated on 36 parameters by three independent judges. Swallow-related hyoid bone movement, computed from digitized segments of the videofluoroscopic data, was compared pre- and postsurgically. All patients showed at least mild abnormality of the oropharyngeal swallow preoperatively. Abnormalities involved all stages of swallowing in nine of the ten patients; however, the oral preparatory/oral stage was relatively more impaired than the pharyngeal stage in the majority of patients. Postsurgically, all patients exhibited at least a mild oropharyngeal swallowing impairment. New or increased postoperative deficits involved the pharyngeal stage of swallowing, whereas oral stage abnormalities were generally improved or unchanged following surgery. Swallow-related hyoid kinematics were highly variable both before and following surgery. Anterior hyoid bone excursion was significantly reduced postoperatively in one patient and significantly increased in one patient. Patients with esophageal cancer exhibit oropharyngeal dysphagia, with different profiles of abnormality before and following esophagectomy.

Cerebral cortical representation of automatic and volitional swallowing in humans

Although the cerebral cortex has been implicated in the control of swallowing, the functional organization of the human cortical swallowing representation has not been fully documented. Therefore, the present study determined the cortical representation of swallowing in fourteen healthy right-handed female subjects using single-event-related functional magnetic resonance imaging (fMRI). Subjects were scanned during three swallowing activation tasks: a naïve saliva swallow, a voluntary saliva swallow, and a water bolus swallow. Swallow-related laryngeal movement was recorded simultaneously from the output of a bellows positioned over the thyroid cartilage. Statistical maps were generated by computing the difference between the magnitude of the voxel time course during 1) a single swallowing trial and 2) the corresponding control period. Automatic and volitional swallowing produced activation within several common cortical regions, the most prominent and consistent being located within the lateral precentral gyrus, lateral postcentral gyrus, and right insula. Activation foci within the superior temporal gyrus, middle and inferior frontal gyri, and frontal operculum also were identified for all swallowing tasks. In contrast, activation of the caudal anterior cingulate cortex was significantly more likely in association with the voluntary saliva swallow and water bolus swallow than the naïve swallow. These findings support the view that, in addition to known brain stem areas, human swallowing is represented within a number of spatially and functionally distinct cortical loci which may participate differentially in the regulation of swallowing. Activation of the insula was significantly lateralized to the right hemisphere for the voluntary saliva swallow, suggesting a functional hemispheric dominance of the insula for the processing of swallowing.

Synthesis and physical investigation of donor-donor and acceptor-acceptor end-functionalized monodisperse poly(triacetylene) oligomers

Two series of monodisperse, terminally donor-donor [D-D, D=4-(dimethylamino)phenyl] and acceptor-acceptor [A-A, A=4-nitrophenyl] functionalized poly(triacetylene) (PTA) oligomers ranging from monomer to hexamer were synthesized by oxidative Hay oligomerization under end-capping conditions. The corresponding D-D and A-A end-substituted polymers with an average degree of polymerization (DP) of n approximately 18 and n approximately 12, respectively, were also prepared and served as reference points for the corresponding infinitely long polymers. These terminally functionalized PTA oligomers and polymers are yellow- to orange-colored compounds, displaying excellent solubility in aprotic solvents with melting points above 200 degrees C for the hexamers. For the 4-(dimethylamino)phenyl substituted compounds, a consistent first oxidation potential around +0.42 V versus Fc/Fc+ (ferrocene/ferricinium) was observed, whereas the 4-nitrophenyl functionalized systems underwent a reversible reductive two-electron transfer around -1.40V versus Fc/Fc+. The nature of the end-groups has a dramatic influence on the electronic absorption spectra. Saturation of the linear optical properties in the D-D series occurs at significantly shorter chain-length [effective conjugation length (ECL) of n approximately 4 monomer units] than in the A-A substituted or the previously reported Me3Si- and Et3Si-end-capped PTA oligomer series (ECL: n approximately 10 monomer units). Similar observations with respect to the ECL were made by measurement of the Raman-active v(C triple bound C) stretches. Third-harmonic generation (THG) and degenerate four-wave mixing (DFWM) experiments showed that shorter oligomers of terminally D-D or A-A functionalized PTAs display higher second hyperpolarizabilities gamma than the corresponding R3Si-end-capped series (R=alkyl). Moreover, they disclose a distinct peak of the nonlinearity per monomer unit at intermediate backbone lengths. In THG experiments, the second hyperpolarizabilities for long D/A-functionalized PTA oligomers attained the same saturation values as observed for the corresponding R3Si-end-capped rods. The nonlinearities measured by DFWM of the D-D and A-A substituted PTAs were found to be larger than for the silylated ones, which can be explained by the closeness of the two-photon resonance.

Monodisperse poly(triacetylene) oligomers extending from monomer to hexadecamer: joint experimental and theoretical investigation of physical properties

A series of monodisperse Et3-Si-end-capped poly(triacetylene) (PTA) oligomers ranging from monomer to hexadecamer was prepared by a fast and efficient statistical deprotection-oxidative Hay oligomerization protocol. The PTA oligomers exhibit an increasingly deep-yellow color with lengthening of the pi-conjugated backbone, feature excellent solubility in aprotic solvents, and exhibit melting points up to > 22 degrees C for the hexadecameric rod. This new dramatically extended oligo(enediyne) series now enables to investigate the evolution of the physico-chemical effects in PTAs beyond the linear 1/n versus property regime into the higher oligomer region where saturation becomes apparent. We report the results of joint experimental and theoretical studies, including analysis of the 13C NMR spectra, evaluation of the linear (UV/ Vis) and nonlinear [third-harmonic generation (THG) and degenerate four-wave mixing (DFWM)] optical properties, and characterization of the redox properties with cyclic and steady-state voltammetry. Up to the hexadecameric rod, an increasingly facile one-electron reduction step is observed, showing at the stage of the dodecamer, a leveling off tendency from the linear correlation between the inverse number of monomer units and the first reduction potential. The effective conjugation length (ECL) determined by means of UV/Vis spectroscopy revealed a pi-electron-delocalization length of about n = 10 monomeric units, which corroborates well with the oligomeric length for which in the 13C NMR spectrum C(sp2) and C(sp) resonances start to overlap. Third-harmonic generation (THG) and degenerate four-wave mixing (DFWM) measurements revealed for the second-order hyperpolarizability gamma a power law increase gammma-alpha-n(a) for oligomers up to the octamer with exponential factors a= 2.46+/-0.10 and a=2.64+/-0.20, respectively, followed by a smooth saturation around n = 10 repeating units. The power law coefficient a calculated with the help of the valence effective Hamiltonian (VEH) method combined to a sum-over-states (SOS) formalism corroborates well with the values found by both THG and DFWM experiments. Up to the PTA heptamer, INDO (intermediate neglect of differential overlap)-calculated gas-phase ionization potentials and electron affinities obey a linear relationship as a function of the inverse number of monomer units displaying a strong electron-hole symmetry. The onset of saturation for the electron affinity is calculated to occur around the octamer, in accordance with experimentally obtained results from electrochemical measurements.

The evolution of modern plate osteosynthesis

Plate osteosynthesis is still recognized as the treatment of choice for most articular fractures, many metaphyseal fractures, and certain diaphyseal fractures such as in the forearm. Since the 1960s, both the techniques and implants used for internal fixation with plates have evolved to provide for improved healing. Most recently, plating methods have focused on the principles of 'biological fixation'. These methods attempt to preserve the blood supply to improve the rate of fracture healing, decrease the need for bone grafting, and decrease the incidence of infection and re-fracture. The purpose of this article is to provide a brief overview of the history of plate osteosynthesis as it relates to the development of the latest minimally invasive surgical techniques.

Uptake and incorporation of docosahexaenoic acid (DHA) into neuronal cell body and neurite/nerve growth cone lipids: evidence of compartmental DHA metabolism in nerve growth factor-differentiated PC12 cells

Docosahexaenoic acid (DHA) accumulates in nerve endings of the brain during development. It is released from the membrane during ischemia and electroconvulsive shock. DHA optimizes neurologic development, it is neuroprotective, and rat adrenopheochromocytoma (PC12) cells have decreased PLA2 activity when DHA is present. To characterize DHA metabolism in PC12 cells, media were supplemented with [3H]DHA or [3H]glycerol. Fractions of nerve growth cone particles (NGC) and cell bodies were prepared and the metabolism of the radiolabeled substrates was determined by thin-layer chromatography. [3H]glycerol incorporation into phospholipids indicated de novo lipid synthesis. [3H]DHA uptake was more rapid in the cell bodies than in the NGC. [3H]DHA first esterified in neutral lipids and later in phospholipids (phosphatidylethanolamine). [3H]glycerol primarily labeled phosphatidylcholine. DHA uptake was compartmentalized between the cell body and the NGC. With metabolism similar to that seen in vivo, PC12 cells are an appropriate model to study DHA in neurons.

Transport properties of the host cell membrane

The malaria-infected erythrocyte shows an increased permeability to a wide range of solutes. The increase is mediated in part by parasite-induced new permeation pathways (NPP) and in part (for some solutes, under some conditions) by increased activity of endogenous transporters. The NPP provide the major route for the influx into the infected cell of a number of essential nutrients, but although the functional characteristics of these pathways are understood in some detail, they are yet to be identified at a molecular level. Lucifer yellow, a fluorescent anion, is taken up by malaria-infected erythrocytes to a much greater extent than uninfected erythrocytes via a pathway that differs in its pharmacological characteristics from the NPP. The nature, origin and location of this pathway remain to be established.

Iontophoresis of lysophosphatidic acid into rabbit cornea induces HSV-1 reactivation: evidence that neuronal signaling changes after infection

PURPOSE

Lysophosphatidic acid induces neurite retraction; it is also present in tears and aqueous humor. We determined whether lysophosphatidic acid induces HSV-1 reactivation in latently infected rabbits and whether the nerve growth associated protein GAP-43 undergoes posttranslational modification during the course of HSV-1 infection.

METHODS

Rabbits were infected with HSV-1 and acute infection was documented by slit lamp examination. Corneas of latently infected rabbits were treated with lysophosphatidic acid or lysophosphatidylserine (structurally similar but lacking biological potency). For application to the cornea, these compounds were impregnated into collagen shields, applied as topical drops, or iontophoresed. In another experiment, corneas of latently infected rabbits were either untreated or treated iontophoretically with lysophosphatidic acid, lysophosphatidylserine, or saline. Ocular swabs detected shedding of infectious virus. Western blot and immunoprecipitation identified GAP-43 in corneal extracts and densitometry of silver-stained isoelectric focusing gels measured changes in GAP-43 isoform abundance.

RESULTS

Iontophoresis of lysophosphatidic acid induced HSV-1 shedding more frequently than lysophosphatidylserine or saline. Viral shedding induced by collagen shield and topical drop administration was low and not significantly different for lysophosphatidic acid and lysophosphatidylserine. Five discrete GAP-43 isoforms predominated in the IEF gels. Most abundant were the pI 4.7 band in uninfected cornea and the pI 5.05 band in latently-infected cornea. Compared to latently-infected cornea, there was no significant change in isoform abundance 1 h after lysophosphatidic acid iontophoresis, but 24 and 72 h later, the pI 5. 05 band was diminished.

CONCLUSIONS

Lysophosphatidic acid can induce HSV-1 reactivation and changes in GAP-43 pI suggest that posttranslational modifications, possibly related to phosphorylation and ADP-ribosylation, are occurring during HSV-1 latency and after LPA is iontophoretically applied to the cornea. How lysophosphatidic acid-induced signaling, HSV-1 reactivation, and GAP-43 pI are related remains to be determined.

Scaling law for second-order hyperpolarizability in poly(triacetylene) molecular wires

Poly(triacetylenes) are rodlike molecules with electrons delocalized over a one-dimensional path. We show that they exhibit a power-law dependence of the second-order hyperpolarizability gamma on the monomer unit n for short molecules and a smooth saturation toward a linear increase in longer molecules. The power law of gamma?n(a) with a approximately 2.5 from dengenerate four-wave mixing and third-harmonic generation measurements is in good agreement with quantum-chemical calculations. The critical conjugation length for saturation in the three cases is shown to be approximately 60 carbon-carbon bonds, which indicates the upper boundary for the electron delocalization in such a one-dimensional molecular wire.

Features of cortically evoked swallowing in the awake primate (Macaca fascicularis)

Although the cerebral cortex has been implicated in the control of swallowing, the output organization of the cortical swallowing representation, and features of cortically evoked swallowing, remain unclear. The present study defined the output features of the primate "cortical swallowing representation" with intracortical microstimulation (ICMS) applied within the lateral sensorimotor cortex. In four hemispheres of two awake monkeys, microelectrode penetrations were made at </=1-mm intervals, initially within the face primary motor cortex (face-MI), and subsequently within the cortical regions immediately rostral, lateral, and caudal to MI. Two ICMS pulse trains [35-ms train, 0.2-ms pulses at 333 Hz, </=30 microA (short train stimulus, T/S); 3- to 4-s train, 0.2-ms pulses at 50 Hz, </=60 microA (continuous stimulus, C/S)] were applied at </=500-micron intervals along each microelectrode penetration to a depth of 8-10 mm, and electromyographic (EMG) activity was recorded simultaneously from various orofacial and laryngeal muscles. Evoked orofacial movements, including swallowing, were verified by EMG analysis, and T/S and C/S movement thresholds were determined. Effects of varying ICMS intensity on swallow-related EMG properties were examined by applying suprathreshold C/S at selected intracortical sites. EMG patterns of swallows evoked from various cortical regions were compared with those of natural swallows recorded as the monkeys swallowed liquid and solid material. Results indicated that swallowing was evoked by C/S at approximately 20% of 1,569 intracortical sites where ICMS elicited an orofacial motor response in both hemispheres of the two monkeys, typically at C/S intensities </=30 microA. In contrast, swallowing was not evoked by T/S in either monkey. Swallowing was evoked from four cortical regions: the ICMS-defined face-MI, the face primary somatosensory cortex (face-SI), the region lateral and anterior to face-MI corresponding to the cortical masticatory area (CMA), and an area >5 mm deep to the cortical surface corresponding to both the white matter underlying the CMA and the frontal operculum; EMG patterns of swallows elicited from these four cortical regions showed some statistically significant differences. Whereas swallowing ONLY was evoked at some sites, particularly within the deep cortical area, swallowing was more frequently evoked together with other orofacial responses including rhythmic jaw movements. Increasing ICMS intensity increased the magnitude, and decreased the latency, of the swallow-related EMG burst in the genioglossus muscle at some sites. These findings suggest that a number of distinct cortical foci may participate in the initiation and modulation of the swallowing synergy as well as in integrating the swallow within the masticatory sequence.

Effects of functional disruption of lateral pericentral cerebral cortex on primate swallowing

Bilateral cold block of the intracortical microstimulation (ICMS)-defined swallow cortex markedly affected the ability of monkeys to carry out swallowing. Significant changes also occurred in swallow-related electromyographic (EMG) activity patterns. These findings provide further evidence that the lateral pericentral cortex plays a critical role in the initiation and regulation of swallowing in the primate.

A review of a prison cervical cancer screening program in British Columbia

OBJECTIVE

To review a 1995 Pap smear screening program at Burnaby Correctional Centre for Women (BCCW).

METHOD

129 inmates (15%), were screened in BCCW in 1995. General population data were obtained from the British Columbia Cervical Cytology Screening Program (BC CCSP) Registry.

RESULTS

BCCW inmates aged 25-29 years were 11 times more likely to have high grade cytologic abnormalities on Pap smear screening compared with age-matched general population (p < 10(-10). In the 20-34 year age group, 47% of BCCW inmates had received at least one Pap smear in 1992-1994, compared with 87% of the general population (p < 0.001). There was no relationship between Pap smear results and BCCW inmate ethnicity (p = 0.85).

CONCLUSIONS

Prison inmates presented with more severe abnormalities on Pap smear screening at a younger age, and had received Pap smear screening less frequently, compared with the general population.

Docosahexaenoic acid decreases phospholipase A2 activity in the neurites/nerve growth cones of PC12 cells

Docosahexaenoic acid (DHA) accumulates in nerve growth cones (NGC) during perinatal development and it is neuroprotective in ischemia. Because the phospholipases A2 (PLA2) are present in NGC and these enzymes function in both ischemia and long-term potentiation, the relationship between DHA and PLA2 was investigated in the NGC of nerve growth factor-differentiated PC12 cells. When PC12 cells were incubated with [3H]DHA, it primarily esterified in ethanolamine glycerolipids and concentrated initially in cell bodies with similar levels present in the neurite/nerve growth cone (N/NGC) fraction after 4 days. PLA2 activity in the N/NGC fraction was investigated using [14C]arachidonic acid-labeled phosphatidylinositol ([14C-AA]PI) as substrate. Heat denaturation and pharmacological inhibition showed that much of the PLA2 activity was calcium-independent and secretory rather than cytosolic. Supplementing the media with as little as 33 nM DHA significantly reduced PLA2 activity in the N/NGC fraction.

Plate osteosynthesis of the distal femur: surgical techniques and results

Over the past three decades, the techniques for internal fixation of the distal femur have evolved to provide reliably successful results. The improved outcomes of plate osteosynthesis of distal femur fractures are because of better implants, techniques of anatomic reduction and soft tissue handling, and post-fixation stability with early motion. We review the traditional Arbeitsgemeinschaft für Osteosynthesefragen (AO) surgical techniques for plate osteosynthesis of the distal femur and the results reported using these methods.

Recommendations for recording and calculating the incidence of selected clinical diseases of dairy cattle

The report upon which the current discussion is based was prepared in response to the increasing interest of the dairy industry in the recording of clinical disease data. The major objective was to introduce guidelines and standards for the recording and presentation of the diseases of dairy cattle. Eight clinically identifiable diseases of economic importance to the dairy industry were considered: milk fever, retained placenta, metritis, ketosis, left displaced abomasum, cystic ovarian disease, lameness, and clinical mastitis. Standardized definitions for these diseases were established through consultation with industry partners. Two approaches to summarization and reporting were proposed. For retrospective analysis, which is used when historical data are summarized for genetic evaluation for example, lactational incidence risk (cumulative incidence) has been recommended. For current analysis, which is used for herd health monitoring, a true incidence rate has been recommended. Milk fever and retained placenta were exceptions to the latter because of their short periods of risk. For these two diseases, lactational incidence risks are reported.

The association between cryptococcal variety and immunocompetent and immunocompromised hosts

The varieties of Cryptococcus neoformans serotypes are neoformans and gattii. Data suggest an association between cryptococcal variety and host immune status. In addition, the two varieties differ in their epidemiology and pathogenicity. Furthermore, symptoms, outcome, and response of cryptococcosis to antifungal therapy may vary. The two varieties also differ in immune-modulating effects. Sparse clinical data suggest var. gattii is more virulent and may be more recalcitrant to antifungal therapy. Also, its infections produce more sequelae. A better understanding of how cryptococcal variety influences the clinical course and response to the treatment of cryptococcosis is needed. Clinicians should be aware of the association, especially in patients with refractory disease. It may be useful to type the isolate to the variety level and administer prolonged antifungal therapy.

Association of occlusal, periodontal, and dietary factors with the presence of non-carious cervical dental lesions

PURPOSE

To investigate in vivo the relationship of occlusal stress factors, periodontal health status, and acidic dietary patterns to the presence of non-carious cervical lesions (NCCL) in a convenience sample of undergraduate clinic, adult dental patients.

MATERIALS AND METHODS

Forty three subjects who met the entry criteria were admitted into the study; 178 teeth exhibiting NCCL were evaluated. A dietary assessment focusing on acidic food/beverage intake was used to evaluate nutritional intake over the most recent 24-hour period. Periodontal evaluation included intraoral measurement of gingival attachment loss, assessment of tooth mobility, and radiographic interpretation of percent bone loss using the Schei ruler method. Among the occlusal factors evaluated were shape and orientation of NCCL, presence and location of wear facets, and symptoms and characteristics of centric and eccentric occlusal function.

RESULTS

95% of teeth examined exhibited functional wear facets, indicating a systematic relationship with presence of NCCL (Chi Square = 16.9, P < 0.0001); 48% displayed buccal or incisal facets; 64% were accompanied by balancing interferences in lateral excursion; 98.3% had mobility scores < or = 1; there was no significant association between mobility and facets present (Chi Square = 3.04, P = 0.21); and, no relationship with dietary patterns was found. Group function, that may evolve with age, and/or traumatic occlusion factors may be related to etiology of NCCL. Longitudinal controlled clinical trials are needed to confirm suspected etiologies and establish treatment guidelines for non-carious cervical lesions.

Child abuse and neglect: assessment of dental students' attitudes and knowledge

Although many North American dental schools have increased their curriculum hours dedicated to the issue of child maltreatment, the majority of schools still allocate only one to two clock hours for this subject. The purpose of this study was to evaluate the self-perceived knowledge of and attitude toward child abuse and neglect, of undergraduate dental students at the University of Texas Dental Branch at Houston, as well as the effectiveness of the various educational methods used in the instruction of this material. Students in general, recognized a need for improvement of both the quality and quantity of this aspect of their undergraduate curriculum. The results indicate, however, that the child maltreatment curriculum at this institution had minimal effect on the acquisition and retention of information related to this subject. Dental educators have the responsibility to see that their students are competent, not only in the technical aspects of dentistry, but in their social responsibilities, as well. The ability to recognize suspected cases of child maltreatment is such a responsibility.

Functional properties of neurons in the primate tongue primary motor cortex during swallowing

Recent studies conducted in our laboratory have suggested that the tongue primary motor cortex (i.e., tongue-MI) plays a critical role in the control of voluntary tongue movements in the primate. However, the possible involvement of tongue-MI in semiautomatic tongue movements, such as those in swallowing, remains unknown. Therefore the present study was undertaken in attempts to address whether tongue-MI plays a role in the semiautomatic tongue movements produced during swallowing. Extracellular single neuron recordings were obtained from tongue-MI, defined by intracortical microstimulation (ICMS), in two awake monkeys as they performed three types of swallowing (swallowing of a juice reward after successful tongue task performance, nontask-related swallowing of a liquid bolus, and nontask-related swallowing of a solid bolus) as well as a trained tongue-protrusion task. Electromyographic activity was recorded simultaneously from various orofacial and laryngeal muscles. In addition, the afferent input to each tongue-MI neuron and ICMS-evoked motor output characteristics at each neuronal recording site were determined. Neurons were considered to show swallow and/or tongue-protrusion task-related activity if a statistically significant difference in firing rate was seen in association with these behaviors compared with that observed during a control pretrial period. Of a total of 80 neurons recorded along 40 microelectrode penetrations in the ICMS-defined tongue-MI, 69% showed significant alterations of activity in relation to the swallowing of a juice reward, whereas 66% exhibited significant modulations of firing in association with performance of the trained tongue-protrusion task. Moreover, 48% showed significant alterations of firing in relation to both swallowing and the tongue-protrusion task. These findings suggest that the region of cortex involved in swallowing includes MI and that tongue-MI may play a role in the regulation of semiautomatic tongue movement, in addition to trained motor behavior. Swallow-related tongue-MI neurons exhibited a variety of swallow-related activity patterns and were distributed throughout the ICMS-defined tongue-MI at sites where ICMS evoked a variety of types of tongue movements. These findings are consistent with the view that multiple efferent zones for the production of tongue movements are activated in swallowing. Many swallow-related tongue-MI neurons had an orofacial mechanoreceptive field, particularly on the tongue dorsum, supporting the view that afferent inputs may be involved in the regulation of the swallowing synergy.

Managed care guidelines for the economic evaluation of pharmaceuticals

Foundation Health Corporation, through its National Pharmacy and Therapeutics Committee, requires all pharmaceutical manufacturers and others who wish products to be considered for formulary listing to meet evidentiary and analytical standards in their submission documentation. This article details the evidentiary and analytical standards required from those making submissions and describes the methodological basis of the guidelines. This is the first time, as far as the authors are aware, that a managed care health system in the United States has required formulary submissions not only to meet clinical and economic evaluation standards, but also to take explicit account of the perspective of the managed care group in applying these techniques. Submissions are required to take what is described as a systems impact perspective. This approach is quite different, in both evidentiary and analytical terms, from standards required by health systems in other countries and standards for the economic evaluation of pharmaceuticals proposed by expert groups in the United States.

Dysphagia following anterior cervical spine surgery

Although previous reports have identified dysphagia as a potential complication of anterior cervical spine surgery (ACSS), current understanding of the nature and etiologies of ACSS-related dysphagia remains limited. The present study was undertaken to describe the patterns of dysphagia that may occur following ACSS. Thirteen patients who exhibited new-onset dysphagia following ACSS were studied retrospectively by means of chart review and videofluoroscopic swallow study analysis. Results indicated that a variety of swallowing impairments occurred following ACSS. In 2 patients, prevertebral soft tissue swelling near the surgical site, deficient posterior pharyngeal wall movement, and impaired upper esophageal sphincter opening were the most salient videofluoroscopic findings. In another 5 patients, the pharyngeal phase of swallowing was absent or very weak, with resulting aspiration in 3 cases. In contrast, an additional 4 patients exhibited deficits primarily of the oral preparatory and oral stages of swallowing including deficient bolus formation and reduced tongue propulsive action. Finally, 2 patients exhibited impaired oral preparatory and oral phases, a weak pharyngeal swallow, as well as prevertebral swelling. Thus, a variety of swallowing deficits, due possibly to neurological and/or soft tissue injuries, may occur following ACSS.

Multiple chemical sensitivities, including iatrogenic allergic contact dermatitis, in a patient with chronic actinic dermatitis: implications for management

BACKGROUND

Chronic actinic dermatitis represents a spectrum of photosensitive dermatoses. Phototesting and photopatch testing are necessary to elucidate the specific subtype. Such patients may have multiple cutaneous allergies and photoallergies.

OBJECTIVE

This is a case report of a patient with chronic actinic dermatitis whose condition was worsened by certain sunscreens and corticosteroids. Our purpose was to identify the specific subtype of chronic actinic dermatitis and cutaneous allergens.

METHODS

Phototesting to UVB and UVA was performed. Photopatch testings to standard photoallergens and to Photoplex sunscreen ingredients was performed. Patch testing to standard allergens and proprietary corticosteroids was performed.

RESULTS

Positive photoallergies to Photoplex sunscreen and the UVA screen within Photoplex, Parsol 1789 (4-tert-butyl-4'-methoxydibenzoyl-methane), were identified. Positive allergies to Aclovate (alclometasone dipropionate) cream and ointment and Locoid (hydrocortisone butyrate) ointment were identified. The patient showed increased UVB sensitivity.

CONCLUSION

This is a case report of a patient with chronic actinic dermatitis. A relevant photoallergy to Parsol 1789 and corticosteroid sensitivities to aclometasone and hydrocortisone butyrate were identified. Multiple cutaneous allergens may be identified in patients with chronic actinic dermatoses, and avoidance of known allergens may result in significant improvement of the chronic dermatitis.

Initial assessment and management of common fractures

The initial assessment and management of all fractures follows a standard protocol. All fractured extremities require a thorough neurovascular examination and evaluation of the skin. Fractures are evaluated and described using standard terminology. These important descriptors include open versus closed fractures, the anatomic location of the fracture, the degree and type of displacement, and the fracture pattern. This forces one to become familiar with the personality of the fracture and ultimately facilitates patient care.

Altered expression and changing distribution of the nerve growth associated protein GAP-43 during ocular HSV-1 infection in the rabbit

This research examines changes that occur in neurons during corneal herpes simplex virus (HSV-1) infection and focuses on the nerve growth associated protein GAP-43. Cornea and trigeminal ganglion (TG) of New Zealand white rabbits were examined after inoculation of the McKrae and 17 Syn+ strains of HSV-1 to the cornea. Rabbit tissues were taken during acute, latent and induced reactivation stages of infection. Systemic immunosuppression (intravenous injections of cyclophosphamide and dexamethasone) was used to induce reactivation. Western blotting, immunoblotting and autoradiography with the same antibody were used respectively to verify antibody specificity, measure changes in GAP-43 concentration and localize GAP-43 to neurons in the TG. During acute infection, corneal GAP-43 increased significantly while no change was seen in the TG. GAP-43 content was elevated in TG and cornea during viral latency (post-inoculation days 84-154) for both HSV-1 strains. When latent virus was reactivated, the corneal concentration of GAP-43 was more than double that of normal rabbits and the concentration of GAP-43 in TG was reduced compared to the non-reactivated, latently-infected TG. In summary, HSV-1 infected TG neurons expressed more GAP-43 than control neurons and immunosuppressive therapy led not only to viral reactivation and increased GAP-43 concentrations in cornea but also to decreased GAP-43 concentrations in TG. These results suggest that factors which maintain HSV-1 latency and induce reactivation could be linked to elements regulating GAP-43 expression.

Light adaptation of cyclic electron transport through Photosystem I in the cyanobacterium Synechococcus sp. PCC 7942

Photosystem I-driven cyclic electron transport was measured in intact cells of Synechococcus sp PCC 7942 grown under different light intensities using photoacoustic and spectroscopic methods. The light-saturated capacity for PS I cyclic electron transport increased relative to chlorophyll concentration, PS I concentration, and linear electron transport capacity as growth light intensity was raised. In cells grown under moderate to high light intensity, PS I cyclic electron transport was nearly insensitive to methyl viologen, indicating that the cyclic electron supply to PS I derived almost exclusively from a thylakoid dehydrogenase. In cells grown under low light intensity, PS I cyclic electron transport was partially inhibited by methyl viologen, indicating that part of the cyclic electron supply to PS I derived directly from ferredoxin. It is proposed that the increased PSI cyclic electron transport observed in cells grown under high light intensity is a response to chronic photoinhibition.

Preparing for the "silver age of dentistry"

Providing oral health care to older adults will be a challenging and rewarding part of dental practice in the years ahead. It will include understanding normal aging, appreciation of the pathophysiology of chronic diseases experienced by many elderly, and application of key principles of pharmacology in care of patients receiving medications for treatment of these diseases. It will involve an understanding of the interaction of systemic conditions with oral health status, adequate diagnosis of oral disease, and appropriate rational treatment planning with a strong emphasis on preventive dentistry. It will include care provided in nursing homes or during housecalls for the homebound. Dentist-geriatricians will be working with teams of healthcare professionals that include physicians, dentists, podiatrists, ophthalmologists, nurses, social workers, nutritionists, pharmacists, and occupational and physical therapists. Above all, the team will provide skilled compassionate care, which is always good business!

Management of dry mouth in elderly patients

Xerostomia is not a natural consequence of the aging process. Although dry mouth is not often found to be a chief complaint of elderly patients, it is a common problem that usually receives inadequate attention. Xerostomia is the feeling of dry mouth due to insufficient secretion of saliva. It is most common among the elderly as a result of adverse effects of drug therapy, head and neck radiation, or autoimmune diseases. Chronic xerostomia has a debilitating effect on the integrity of the hard and soft tissues of the mouth. It often causes difficulty in speaking, tasting, eating, swallowing and denture retention. The goals of treatment are to stimulate salivary flow, or to restore oral moistness and prevent or alleviate the uncomfortable, harmful sequelae of xerostomia. Dentists can significantly enhance the quality of life for xerostomia sufferers by effectively managing the xerostomia sequelae in a compassionate, understanding manner.

Retiring some myths about aging and oral health

Research on the oral health status of elderly populations has been limited in frequency and scope. There is a lack of good descriptive and longitudinal data on salivary gland function, oral mucosal status, and oral sensory performance in health and disease across the adult life span. Thus, confusion for practitioners and patients alike arises from unsubstantiated stereotypes about aging and oral health. There are some commonalities in the origins of the myths discussed in this article. First, many aging generalizations were based on studies that did not account for the health and medication status of the subjects. Second, most aging studies are cross-sectional designs which can result in misleading conclusions due to the age cohort effect. Third, many studies on the histology of aging oral tissues were laboratory animal studies, with results that cannot be generalized to human populations. Fourth, findings on oral health changes are often confounded or influenced by differences in functional status (e.g., the ability to care for oneself), nutritional health, health beliefs and expectations within the study subjects. Fifth, other changes due to aging may have an indirect effect on oral health, for example, an age-related decline in immune function. Sixth, the "older-old" group of elderly commonly labor under misconceptions of normal aging changes. Historically they have not sought dental care as often as the younger elders. This health care seeking behavior is expected to change dramatically when the baby boom generation joins the elderly ranks. The goals of oral health care for the elderly are consistent with those of other health care providers involved in geriatric care, namely maximizing functional performance, fostering independence, and enhancing their quality of life. Dental professionals would be well advised to apply a healthy dose of skepticism to any generalizations about debilitating changes in oral health due to aging alone. Most changes in oral health experienced by the elderly are not the result of age itself, but are the consequences of systemic disease, pharmacotherapy, functional disabilities, and cognitive impairment. When unexplained deleterious changes are seen in the oral health of elderly patients, the knowledgeable and reflective practitioner will account for local, systemic, and environmental factors in formulating a plan of care. In the opening paragraph, questions were posed about the mucosal integrity of a "little old lady." The most beneficial approach for her and all our older patients is to plan treatment utilizing current knowledge about aging and avoiding the traps created by myths and stereotypes. It is time to retire these myths before the baby boomers join the ranks of the retired.

Hyperosmolar nonketotic diabetic syndrome following treatment of human immunodeficiency virus infection with didanosine

OBJECTIVE

To determine whether didanosine (DDI), one of the drugs commonly used to treat infection with human immunodeficiency virus (HIV), contributes to the development of diabetes and hyperosmolar nonketotic diabetic syndrome (HNKDS).

CASE SUMMARY

One female patient was treated with DDI for infection with HIV during pregnancy. Soon after starting DDI treatment, she developed diabetes, which progressed to HNKDS.

CONCLUSIONS

Although not reported in the literature, hyperglycemia following treatment with DDI has been noted in 82 patients and is usually associated with pancreatitis. DDI should be recognized as one of the drugs known to potentially cause diabetes and HNKDS. With the increasing use of DDI and other drugs that cause hyperglycemia, such as pentamidine and dapsone, blood glucose should be monitored frequently in the HIV-infected patients.