Murine keratocytes function as antigen-presenting cells

Keratocytes express MHC class I molecules constitutively, and keratocytes stimulated with IFN-gamma express MHC class II molecules. Unstimulated keratocytes constitutively express B7-1 and ICAM-1, as well as low levels of CD40 and 4-1BBL. These findings indicate that keratocytes may deliver both antigen-specific and costimulatory signals to CD4(+) and CD8(+) T cells. To demonstrate that keratocytes expressing B7-1 provide a costimulatory signal to T cells, CD4(+) or CD8(+) mouse T cells were incubated with anti-CD3 mAb and irradiated keratocytes. Enhanced proliferation of both CD4(+) and CD8(+) T cells occurred, and could be inhibited by anti-B7-1 mAb, indicating T cell costimulatory activity by B7-1 on the keratocytes. To demonstrate that keratocytes can deliver an antigen-specific signal, CD4(+) and CD8(+) T cells from herpes-infected mice were incubated with HSV-1-infected, irradiated keratocytes. The resulting T cell proliferation and production of Th1 cytokines (IL-2, IFN-gamma) indicated T cell activation by antigens presented by the infected keratocytes. These results show that keratocytes in the corneal stroma of the mouse can function as antigen-presenting cells and, thus, may play a role in immune-mediated stromal inflammation such as herpetic stromal keratitis.

Quantitative analysis of the principle soy isoflavones genistein, daidzein and glycitein, and their primary conjugated metabolites in human plasma and urine using reversed-phase high-performance liquid chromatography with ultraviolet detection

Soy isoflavones are becoming of increasing interest as nutritional agents which can be used to combat osteoporosis and hyperlipidemia, and are also being considered as potential cancer chemopreventive compounds. However, prior to their formulation and distribution as therapeutic agents, thorough pharmacokinetic and toxicological assessment needs to be completed in men and women in a variety of health conditions in order to ensure their therapeutic efficacy and safety. At this time, studies of purified soy isoflavones are possible, and are being designed to fully evaluate the pharmacological utility of these preparations. In support of these studies, quantitative analysis of soy isoflavones in biological fluids can be accomplished with a wide variety of methods and analytical instrumentation. However, the relatively ubiquitous presence of high-performance liquid chromatography with ultraviolet detection (HPLC-UV) in most analytical laboratories, the relative ease of its operation, and the lesser expense of this instrumentation as compared to more sophisticated techniques such as liquid chromatography-mass spectrometry, offers some distinct advantages for its use in pharmacokinetic studies. In this manuscript, the development and validation of an HPLC-UV method for the quantitation of the principal soy isoflavones, genistein, daidzein, and glycitein, and their primary metabolites, in human plasma and urine is described. This analytical approach allows for pharmacologically relevant concentrations of the analytes and their principle metabolites to be detected, and has been validated in close agreement with the US Food and Drug Administration's guidelines for the validation of methods to be used in support of pharmacokinetic studies.

IGF-I as a mediator of VIP/activity-dependent neurotrophic factor-stimulated embryonic growth

IGF-I and the IGF-I receptor are necessary for normal embryonic growth. VIP is an important regulator of early postimplantation growth and acts indirectly through the release of other factors, including activity-dependent neurotrophic factor. The relationship of IGF-I growth regulation to VIP/activity-dependent neurotrophic factor-stimulated growth was examined with whole cultured embryonic d 9.5 mouse embryos. Somite numbers and DNA and protein contents were measured in embryos treated with IGF-I, anti-IGF-I, VIP, activity-dependent neurotrophic factor, and anti-activity-dependent neurotrophic factor-14 (antiserum to an activity-dependent neurotrophic factor agonist). IGF-I mRNA content was measured after incubation with and without VIP for 30 and 60 min using competitive RT-PCR. IGF-I induced a significant, dose-dependent increase in growth as measured by somite number, DNA levels, and protein content. Furthermore, anti-IGF-I inhibited embryonic growth and also prevented exogenous IGF-mediated growth. Both VIP- and activity-dependent neurotrophic factor-stimulated growth were blocked by anti-IGF-I, whereas anti-activity-dependent neurotrophic factor-14 had no detectable effect on IGF-I-induced growth. Treatment with VIP resulted in a 2-fold increase in embryonic IGF-I mRNA. These data suggest that IGF-I is a downstream mediator of VIP and activity-dependent neurotrophic factor in a regulatory pathway coordinating embryonic growth and that VIP may function as a regulator of IGF-I gene expression in the embryo.

Effect of famciclovir on herpes simplex virus type 1 corneal disease and establishment of latency in rabbits

Famciclovir (FCV) is efficacious in the treatment of acute herpes zoster and recurrent genital infections but has not been used to treat ocular herpes simplex virus (HSV) infections. We evaluated the efficacy of orally administered FCV in treating HSV-1 epithelial keratitis and determined its effects on the establishment of latency and subsequent reactivation. Rabbits were inoculated with HSV-1 strain 17 syn+ and treated twice daily with increasing concentrations of FCV (60 to 500 mg/kg of body weight). This resulted in a significant, dose-dependent improvement in keratitis scores, as well as prolonged survival. Regardless of the dose of drug used, all groups exhibited the high rates of spontaneous and induced reactivation characteristic of 17syn+. The efficacy of 250 mg of FCV per kg was also compared to topical treatment with 1% trifluorothymidine (TFT). Although TFT treatment was more effective at reducing eye disease, FCV-treated rabbits had a better survival rate. Real-time quantitative PCR analysis of rabbit trigeminal ganglia (TG) demonstrated that FCV significantly reduced the HSV-1 copy number compared to that after treatment with TFT or the placebo but not in a dose-dependent manner. In summary, oral FCV treatment significantly reduces the severity of corneal lesions, reduces the number of HSV-1 genomes in the TG, improves survival, and therefore may be beneficial in reducing the morbidity of HSV keratitis in the clinic.

Firefighters' hearing: a comparison with population databases from the International Standards Organization

We investigated firefighters' hearing relative to general population data to adjust for age-expected hearing loss. For five groups of male firefighters with increasing mean ages, we compared their hearing thresholds at the 50th and 90th percentiles with normative and age- and sex-matched hearing data from the International Standards Organization (databases A and B). At the 50th percentile, from a mean age of 28 to a mean age of 53 years, relative to databases A and B, the firefighters lost an excess of 19 to 23 dB, 20 to 23 dB, and 16 to 19 dB at 3000, 4000, and 6000 Hz, respectively. At the 90th percentile, from a mean age of 28 to a mean age of 53 years, relative to databases A and B, the firefighters lost an excess of 12 to 20 dB, 38 to 44 dB, 41 to 45 dB, and 22 to 28 dB at 2000, 3000, 4000, and 6000 Hz, respectively. The results are consistent with accelerated hearing loss in excess of age-expected loss among the firefighters, especially at or above the 90th percentile.

A cAMP response element within the latency-associated transcript promoter of HSV-1 facilitates induced ocular reactivation in a mouse hyperthermia model

Herpes simplex virus type 1 (HSV-1) recombinant strain 17CRE contains a site-directed mutation in the 7-bp CRE consensus sequence located 38 nucleotides upstream of the transcription start site. Scarified mouse corneas received inoculations of 17syn+ (parent), 17CRE, and rescue 17CREr. Slit lamp examination of herpetic lesions and tear film swabs containing infectious virus showed that 17CRE had the same acute phenotype as 17syn+ and 17CREr. At 4 weeks, when the corneas had healed and latency was established, mice received hyperthermic shock. Eye swabs taken 24 h after hyperthermia showed that 17CRE reactivated significantly less than 17syn+ and 17CREr, while no significant differences were found in HSV-1 DNA genome copy numbers and latent virus in the trigeminal ganglia. These results are evidence that this CRE site in the LAT promoter facilitates ocular HSV-1 reactivation in mice.

Long-term results of total shoulder arthroplasty following bone-grafting of the glenoid

BACKGROUND

The marked loss of glenoid bone volume or alteration of glenoid version can affect glenoid component fixation in patients undergoing total shoulder arthroplasty. The purpose of this study was to evaluate the long-term results associated with the use of bone-grafting for restoration of glenoid volume and version at the time of total shoulder arthroplasty.

METHODS

Twenty-one shoulders received an internally fixed, corticocancellous bone graft for the restoration of peripheral glenoid bone stock at the time of total shoulder arthroplasty between 1980 and 1989. Grafting was indicated when glenoid bone stock was insufficient to maintain adequate version or fixation of the prosthesis. Seventeen shoulders were available for follow-up; the average duration of follow-up for the thirteen shoulders that did not have prosthetic failure within the first two years was seventy months. Total shoulder arthroplasty was performed because of osteoarthritis in five shoulders, chronic anterior fracture-dislocation in five, capsulorrhaphy arthropathy in three, inflammatory arthritis in two, recurrent dislocation in one, and failure of a previous arthroplasty in one. All patients had some form of anterior or posterior instability preoperatively. There were five anterior and twelve posterior glenoid defects. Bone from the resected humeral head was used for grafting in fifteen shoulders, and bicortical iliac-crest bone was used in two.

RESULTS

The average glenoid version after grafting was 4 degrees of retroversion, with an average correction of 33 degrees. The graft failed to maintain the original correction in three shoulders due to nonunion, dissolution, or shift. Five total shoulder replacements failed, necessitating glenoid revision at two to ninety-one months postoperatively. The failures were associated with recurrent massive cuff tears (one shoulder), persistent instability (two shoulders), improper component placement (one shoulder), and loss of graft fixation (one shoulder). There were no humeral component failures. According to the criteria of Neer et al., the functional result was rated as excellent in three shoulders, satisfactory in six, and unsatisfactory in eight.

CONCLUSIONS

Despite the finding that eight shoulders had an unsatisfactory functional result at the time of longterm follow-up, corticocancellous grafting of the glenoid successfully restored glenoid version and volume in fourteen of the seventeen shoulders in the present study. Patients with glenoid deficiency often have associated glenohumeral instability, which may affect the results of total shoulder arthroplasty. Bone-grafting of the glenoid is a technically demanding procedure that can restore bone stock in patients with structural defects.

Prevention of fetal demise and growth restriction in a mouse model of fetal alcohol syndrome

Two peptides [NAPVSIPQ (NAP) and SALLRSIPA (ADNF-9)], that are associated with novel glial proteins regulated by vasoactive intestinal peptide, are shown now to provide protective intervention in a model of fetal alcohol syndrome. Fetal demise and growth restrictions were produced after intraperitoneal injection of ethanol to pregnant mice during midgestation (E8). Death and growth abnormalities elicited by alcohol treatment during development are believed to be associated, in part, with severe oxidative damage. NAP and ADNF-9 have been shown to exhibit antioxidative and antiapoptotic actions in vitro. Pretreatment with an equimolar combination of the peptides prevented the alcohol-induced fetal death and growth abnormalities. Pretreatment with NAP alone resulted in a significant decrease in alcohol-associated fetal death; whereas ADNF-9 alone had no detectable effect on fetal survival after alcohol exposure, indicating a pharmacological distinction between the peptides. Biochemical assessment of the fetuses indicated that the combination peptide treatment prevented the alcohol-induced decreases in reduced glutathione. Peptide efficacy was evident with either 30-min pretreatment or with 1-h post-alcohol administration. Bioavailability studies with [(3)H]NAPVSIPQ indicated that 39% of the total radioactivity comigrated with intact peptide in the fetus 60 min after administration. These studies demonstrate that fetal death and growth restriction associated with prenatal alcohol exposure were prevented by combinatorial peptide treatment and suggest that this therapeutic strategy be explored in other models/diseases associated with oxidative stress.

Pharmacologically distinct vasoactive intestinal peptide binding sites: CNS localization and role in embryonic growth

In vitro autoradiography with [125I]vasoactive intestinal peptide revealed that the vasoactive intestinal peptide analogue, stearyl-norleucine17 vasoactive intestinal peptide, reported to be inactive at adenylyl cyclase-linked receptors in astrocytes, displaced a subset of vasoactive intestinal peptide binding sites on rat brain sections. These sites were widespread in adult rat brains and enriched in the olfactory bulb and thalamus, and corresponded to previously demonstrated GTP-insensitive vasoactive intestinal peptide binding sites. Stearyl-norleucine17 vasoactive intestinal peptide also identified receptors in rat lung and liver. In the adult brain, the stearyl-norleucine analog displaced only GTP-insensitive vasoactive intestinal peptide binding sites. In contrast, stearyl-norleucine17 vasoactive intestinal peptide-displaceable sites in the embryonic day 9 mouse appeared to include both GTP-sensitive and GTP-insensitive binding sites. This observation suggested the presence of an embryonic vasoactive intestinal peptide receptor with distinct pharmacological properties. Treatment of whole cultured mouse embryos with stearyl-norleucine17 vasoactive intestinal peptide resulted in stimulation of embryonic growth, with the stearyl-norleucine analog equipotent to vasoactive intestinal peptide, but less efficacious at higher concentrations (10(-7) M). Embryonic growth was inhibited by pituitary adenylyl cyclase-activating peptide and 8-bromoadenosine 3',5'-cyclic monophosphate. In addition, 8-bromoadenosine 3',5'-cyclic monophosphate inhibited stearyl-norleucine17 vasoactive intestinal peptide-stimulated growth. The results of the current study support the hypothesis that vasoactive intestinal peptide regulation of early postimplantation embryonic growth occurs, at least in part, independently of adenylyl cyclase stimulation.

Stress-associated immunomodulation and herpes simplex virus infections

Stress has been shown to modulate an individual's immune system through the release of certain signal molecules such as catecholamines, cytokines and glucocorticoids. These signal molecules can significantly alter the host immune system and leave it susceptible to a primary or recurrent viral infection. Focusing on herpes simplex virus types-1 and -2 as examples, the authors explain how stress-associated immunomodulation can influence the recurrence of herpes simplex viral infections. Specific signal molecules such as epinephrine, interleukin-6, cyclic adenosine monophosphate, glucocorticoids and prostaglandins are upregulated during episodes of acute and chronic stress and have been implicated as effectors of herpes simplex viral reactivation and recurrent disease. The authors suggest that the release of immunomodulating signal molecules due to stress can compromise the host's cellular immune response and trigger herpes simplex viral reactivation.

Pseudomonas aeruginosa protease IV enzyme assays and comparison to other Pseudomonas proteases

Pseudomonas aeruginosa secretes multiple proteases that have been implicated as virulence factors and the detection of each specific enzyme can be difficult to determine. Unlike the three Pseudomonas enzymes that have been well characterized (elastase A, elastase B, and alkaline protease), the activity of protease IV in multiple assays has yet to be described. This study defines new assays for Pseudomonas proteases and compares protease IV activity to the activities of elastase A, elastase B, and alkaline protease. Six in vitro assays were studied: zymography, elastin congo red assay, staphylolytic assay, colorimetric peptide assay, solid-phase colorimetric peptide assay, and poly-l-lysine degradation. Casein zymography distinguished protease IV from elastase B and alkaline protease, and gelatin zymography differentiated all four proteases. The elastin congo red assay detected mainly elastase B while the staphylolytic assay was specific for elastase A. Protease IV activity was assayed specifically by the colorimetric assay and two new assays, the solid-phase colorimetric assay and degradation of poly-L-lysine in the presence of EDTA. Alkaline protease could be specifically assayed by poly-L-lysine degradation in the presence of N-alpha-p-tosyl-L-lysine chloromethyl ketone. The results identified three specific assays for protease IV, a new assay specific for alkaline protease, and showed that protease IV has a distinct enzymatic specificity relative to the three other Pseudomonas proteases.

A series of quinoline analogues as potent inhibitors of C. albicans prolyl tRNA synthetase

A series of quinoline inhibitors of C. albicans prolyl tRNA synthetase was identified. The most potent analogue, 2-(4-bromo-phenyl)-6-chloro-8-methyl-4-quinolinecarboxylic acid, showed IC50 = 5 nM (Ca. ProRS) with high selectivity over the human enzyme.

Increased severity of HSV-1 keratitis and mortality in mice lacking the 2-5A-dependent RNase L gene

PURPOSE

The2',5'-oligoadenylate-dependent RNase L gene functions in the interferon-inducible RNA decay pathway known as the 2-5A system. The purpose of this study was to determine whether the absence of this gene affects the pathogenesis of herpes simplex virus type 1 (HSV-1) ocular infection in the mouse.

METHODS

HSV-1 (strain McKrae) was applied bilaterally to unscarified corneas of RNase L-null mice and congenic controls. To evaluate the severity of herpetic keratitis, slit lamp examinations (SLE) were performed every other day for 14 days. To study corneal histology and apoptosis, HSV-1-inoculated RNase-L-null and congenic control mice, as well as mock-inoculated mice (apoptosis negative control), were killed at 6 and 18 hours postinoculation (PI). Uninoculated mice that underwent corneal scarification (apoptosis positive control) were killed 2 hours after scarification. Eyes were dissected and the corneas processed for light and transmission electron microscopy and the TUNEL assay.

RESULTS

In comparison with the congenic control mice, RNase L-null mice showed significantly more severe herpetic keratitis (PI day 8, SLE score, mean +/- SEM: 3.27 +/- 0.10 vs. 2.34 +/- 0.06; P: < 0.001) and significantly higher mortality (PI day 14, 70% vs. 20%; P: < 0.001). Few apoptotic cells were seen in HSV-1-infected RNase L-null mice, although DNA fragmentation consistent with apoptosis was detected in the corneas of congenic control mice 6 and 18 hours after HSV-1 inoculation and in uninfected mice with scarified corneas. Signs of apoptosis were not present in the mock-infected corneas. Electron microscopic evidence of keratocytic apoptosis was detected only in the uninfected scarified corneas and the HSV-1-infected congenic control corneas.

CONCLUSIONS

The increased severity of ocular disease and increased mortality in the RNase L-null mice provides evidence, for the first time, that the 2-5A system contributes to protection during ocular herpetic infection. The reduced frequency of apoptosis in these mice suggests that one possible mechanism for this protective effect could be the induction of apoptosis in corneal cells as a means of reducing the spread of infectious virus.

VIP and PACAP 38 modulate ibotenate-induced neuronal heterotopias in the newborn hamster neocortex

Intracerebral administration of ibotenate produces, through activation of N-methyl-D-aspartate (NMDA) receptors, neuronal heterotopias in the newborn hamster neocortex: high doses of ibotenate induce periventricular and subcortical neuronal heterotopias, while low doses of ibotenate produce intracortical heterotopias and molecular layer ectopias. Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) are closely related peptides with neurotrophic properties. They share common VPAC1 and VPAC2 receptors, which use cAMP as a second messenger. Previous studies have shown that VIP prevents excitotoxic neuronal death and exacerbates glutamate-induced c-fos neuronal expression. In order to gain new insight into the molecular control of neuronal migration, the present study examined the effects of VIP and PACAP on ibotenate-induced heterotopias in the newborn hamster. Co-treatment with VIP and a high dose of ibotenate produced a pattern of neuronal heterotopias similar to the one observed in animals treated with low doses of ibotenate alone. Pups co-injected with a low dose of ibotenate and a VIP antagonist displayed cortical dysgeneses similar to those observed in animals treated with high doses of ibotenate alone. The modulating effects of VIP on excitotoxin-induced heterotopias were mimicked by forskolin, PACAP, and by a specific VPAC2 receptor agonist but not by a VPAC1 agonist, and were blocked by a protein kinase A (PKA) inhibitor. Taken together, these data suggest that VIP and PACAP can attenuate ibotenate-induced heterotopias in newborn hamster and that this effect is mediated by the VPAC2 receptor utilizing the cAMP-PKA pathway.

Conotoxin TVIIA, a novel peptide from the venom of Conus tulipa 2. Three-dimensional solution structure

The three-dimensional solution structure of conotoxin TVIIA, a 30-residue polypeptide from the venom of the piscivorous cone snail Conus tulipa, has been determined using 2D 1H NMR spectroscopy. TVIIA contains six cysteine residues which form a 'four-loop' structural framework common to many peptides from Conus venoms including the omega-, delta-, kappa-, and muO-conotoxins. However, TVIIA does not belong to these well-characterized pharmacological classes of conotoxins, but displays high sequence identity with conotoxin GS, a muscle sodium channel blocker from Conus geographus. Structure calculations were based on 562 interproton distance restraints inferred from NOE data, together with 18 backbone and nine side-chain torsion angle restraints derived from spin-spin coupling constants. The final family of 20 structures had mean pairwise rms differences over residues 2-27 of 0.18+/-0.05 A for the backbone atoms and 1.39+/-0.33 A for all heavy atoms. The structure consists of a triple-stranded, antiparallel beta sheet with +2x, -1 topology (residues 7-9, 16-20 and 23-27) and several beta turns. The core of the molecule is formed by three disulfide bonds which form a cystine knot motif common to many toxic and inhibitory polypeptides. The global fold, molecular shape and distribution of amino-acid sidechains in TVIIA is similar to that previously reported for conotoxin GS, and comparison with other four-loop conotoxin structures provides further indication that TVIIA and GS represent a new and distinct subgroup of this structural family. The structure of TVIIA determined in this study provides the basis for determining a structure-activity relationship for these molecules and their interaction with target receptors.

Conotoxin TVIIA, a novel peptide from the venom of Conus tulipa 1. Isolation, characterization and chemical synthesis

A novel conotoxin belonging to the 'four-loop' structural class has been isolated from the venom of the piscivorous cone snail Conus tulipa. It was identified using a chemical-directed strategy based largely on mass spectrometric techniques. The new toxin, conotoxin TVIIA, consists of 30 amino-acid residues and contains three disulfide bonds. The amino-acid sequence was determined by Edman analysis as SCSGRDSRCOOVCCMGLMCSRGKCVSIYGE where O = 4-transL-hydroxyproline. Two under-hydroxylated analogues, [Pro10]TVIIA and [Pro10,11]TVIIA, were also identified in the venom of C. tulipa. The sequences of TVIIA and [Pro10]TVIIA were further verified by chemical synthesis and coelution studies with native material. Conotoxin TVIIA has a six cysteine/four-loop structural framework common to many peptides from Conus venoms including the omega-, delta- and kappa-conotoxins. However, TVIIA displays little sequence homology with these well-characterized pharmacological classes of peptides, but displays striking sequence homology with conotoxin GS, a peptide from Conus geographus that blocks skeletal muscle sodium channels. These new toxins and GS share several biochemical features and represent a distinct subgroup of the four-loop conotoxins.

Vasoactive intestinal peptide regulates embryonic growth through the action of activity-dependent neurotrophic factor

Activity-dependent neurotrophic factor is a potent, neuroprotective protein released from astroglia by VIP and accounts in part for the neuroprotective properties of this neuropeptide. The growth-regulatory actions of VIP during embryogenesis may also occur indirectly through the release of activity-dependent neurotrophic factor. Whole cultured day-9 mouse embryos treated with activity-dependent neurotrophic factor (10(-13) M) for 4 hr grew 3.1 somites, compared with 1.6 somites in control embryos. Treated embryos appeared morphologically normal and exhibited significant increases in cross-sectional area, protein, and DNA content and bromodeoxyuridine incorporation. Anti-activity-dependent neurotrophic factor significantly inhibited growth. Co-treatment of embryos with anti-activity-dependent neurotrophic factor inhibited VIP-stimulated growth; however, anti-VIP did not inhibit activity-dependent neurotrophic factor-induced growth. These data indicate that an activity-dependent neurotrophic factor-like substance is an endogenous embryonic growth factor and that VIP-regulated growth occurs, at least in part, through activity-dependent neurotrophic factor.

Regulation of postimplantation mouse embryonic growth by maternal vasoactive intestinal peptide

Vasoactive intestinal peptide (VIP) is an identified regulator of growth in the embryonic day (E) 9-11 mouse. Mouse embryonic and extra-embryonic tissues were studied to identify the source of VIP at this critical time. VIP and mRNA was detected in the decidua/trophoblast at E8 and declined until E10, after which it was not detectable. VIP mRNA was not apparent in the embryo until E11-E12. At E9, cells in decidua had VIP as well as lymphocyte marker (delta and CD3) immunoreactivity. VIP binding sites were dense in the decidua/trophoblast at E6, which gradually decreased until E10. VIP binding sites were detected in embryonic neuroepithelium by E9. The transient presence of VIP binding sites and mRNA in the decidua/trophoblast correlate with the identified period of VIP growth regulation, when VIP mRNA is absent in the embryo. Therefore, these findings suggest that maternal decidual lymphocytes are the source of VIP that regulate early postimplantation embryonic growth.

Discharge of group IV phrenic afferent fibers increases during diaphragmatic fatigue

The discharge of single unit group III (n=7) and group IV (n=8) phrenic afferent fibers was recorded during rhythmic diaphragmatic contractions before and after the onset of fatigue. Compared to pre-fatigue impulse activity, group IV, but not group III, phrenic afferent fibers discharged more (p<0.05) during rhythmic diaphragmatic contractions when the diaphragm was fatigued. This increase in group IV fiber discharge during diaphragmatic fatigue provides electrophysiological evidence consistent with the notion that group IV phrenic afferent fibers comprise the afferent arm of a fatigue-induced inhibitory reflex originating in the diaphragm.

The effects of sexual orientation in the courtroom: a double standard

Homonegativity is a term that many psychologists use to describe irrational fear of homosexuality. Due to a growing number of male rapes in the United States and the unchecked levels of homonegativity, it is hypothesized that homosexuals will be treated differently from heterosexuals in sexual assault trials. Four conditions were examined controlling for the gender and sexuality of both the defendant and the victim and a sexual assault trial text was created controlling for factors known to affect juror's decisions. Seventy-two participants were divided among the four conditions. This research supports the hypothesis with highly significant results. Future research is suggested.

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.