Outcomes of inferior oblique myectomy versus recession combined with lateral rectus recession in V-pattern exotropias

PURPOSE

To compare outcomes of bilateral lateral rectus recession (BLRc) paired with either bilateral inferior oblique myectomy (BIOm) or bilateral inferior oblique recession (BIOc) to correct V-pattern exotropia.

METHODS

The medical records of children (≤18 years) who underwent BLRc with BIOm or BIOc (10 mm) for V-pattern intermittent exotropia between December 2020 and May 2022 and who had at least 6 months' postoperative follow-up were reviewed. Outcomes included horizontal alignment, bilateral inferior oblique action, stereopsis, postoperative exotropia control score, and additional strabismus surgeries. Analysis was stratified by preoperative V pattern into subgroups of 10Δ-14Δ and ≥15Δ.

RESULTS

Fifty patients underwent BLRc with BIOm (n = 26) or BIOc (n = 24), with no difference in age, sex, or follow-up length. Preoperatively, there were no differences in stereopsis, horizontal or vertical deviations in primary position, strabismus control, or inferior oblique overaction (IOOA). The BIOc group had greater preoperative V pattern than the BIOm group (18.1 ± 6.8 D vs 14.3 ± 7.0 D, resp. [P = 0.03]). There was no difference in BLRc surgical dose. At final follow-up (mean, 448 ± 189 days), both groups showed a postoperative decrease in horizontal deviation, amount of V pattern, and IOOA. For patients with ≥15Δ V pattern, BIOm decreased V pattern amount at distance (P = 0.02) and IOOA (P = 0.0035) more than BIOc, and BIOm patients had better control of residual strabismus at distance (P = 0.03) compared with the BIOc group overall, as well as for both V pattern subgroups. Two patients with BIOm and one with BIOc underwent additional strabismus surgery.

CONCLUSIONS

BIOm or BIOc in combination with BLRc decreased the angle of exotropia and improved control. However, BIOm, especially with large V patterns, had a greater effect on decreasing the V pattern and IOOA and showed better control of residual strabismus.

Effect of discharge opioid on persistent postoperative opioid use: a retrospective cohort study comparing tapentadol with oxycodone

Opioid harm can vary by opioid type. This observational study examined the effect of opioid type (oxycodone vs. tapentadol) on rates of persistent postoperative opioid use ('persistence'). We linked hospital and community pharmacy data for surgical patients who were dispensed discharge opioids between 1 January 2016 and 30 September 2021. Patients were grouped by opioid experience ('opioid-naive' having received no opioids in the 3 months before discharge) and formulation of discharge opioid (immediate release only or modified release ± immediate release). Mixed-effects logistic regression models predicted persistence (continued use of any opioid at 90 days after discharge), controlling for key persistence risk factors. Of the 122,836 patients, 2.31% opioid-naive and 27.24% opioid-experienced patients met the criteria for persistence. For opioid-naive patients receiving immediate release opioids, there was no significant effect of opioid type. Tapentadol modified release was associated with significantly lower odds of persistence compared with oxycodone modified release, OR (95%CI) 0.81 (0.69-0.94) for opioid-naive patients and 0.81 (0.71-0.93) for opioid-experienced patients. Among patients who underwent orthopaedic surgery (n = 19,832), regardless of opioid experience or opioid formulation, the odds of persistence were significantly lower for those who received tapentadol compared with oxycodone. This was one of the largest and most extensive studies of persistent postoperative opioid use, and the first that specifically examined persistence with tapentadol. There appeared to be lower odds of persistence for tapentadol compared with oxycodone among key subgroups, including patients prescribed modified release opioids and those undergoing orthopaedic surgery.

Operative Management of Acute Appendicitis is Safe During the COVID-19 Pandemic Shutdown

INTRODUCTION

In the spring of 2020, New York City was one of the first epicenters of the COVID outbreak. In this study, we evaluate the incidence and treatment of appendicitis in two New York City community hospitals during the COVID pandemic.

METHODS

This retrospective study focused on the incidence and outcome of acute appendicitis in the adult population (>18 y old) during peak-COVID periods (March 16, 2020,-June 15, 2020) compared to pre-COVID and post-COVID periods. We compared the number of patients who underwent operative versus nonoperative management, patient demographics, length of stay (LOS), complications, and readmission rates within these time periods. Data are presented as mean ± standard deviation (analysis of variance).

RESULTS

From January 1, 2020 to December 31, 2020, 393 patients presented with acute appendicitis and 321 (81.7%) were treated operatively, compared to 441 total and 366 treated operatively (83%) in 2019 (P = 0.88). During the COVID outbreak, fewer patients presented with appendicitis (mean 6.9 ± 1 pre-COVID case/week, 4.4 ± 2.4 peak-COVID cases/week and 7.6 ± 0.65 post-COVID cases/week, P = 0.018) with no significant difference in the pre-COVID and post-COVID period. There was no difference in LOS between the pre-, peak-, and post-COVID periods with a median of 1 for all the three, (interquartile range (IQR): 0.8-2, 0.6-2, 0.6-2, respectively, P = 0.43). Additionally, there was no difference in 30-day readmission rates (4.2%, 0%, 3.9%, P = 0.99) and postoperative complications (4.2%, 0%, 2.9%, P = 0.98).

CONCLUSIONS

During peak-COVID, there was a significant reduction in the number of patients who presented with acute appendicitis without a post rebound increase in presentation. Those who presented during peak-COVID were able to undergo operative management safely, without affecting LOS or postoperative complications.

Operative Shutdown and Recovery: Restructuring Surgical Operations During the SARS-CoV-2 Pandemic

Background

During the 2020 SARS-CoV-2 outbreak in New York City, hospitals canceled elective surgeries to increase capacity for critically ill patients. We present case volume data from our community hospital to demonstrate how this shutdown affected surgical care.

Methods

Between March 16 and June 14, 2020, all elective surgeries were canceled at our institution. All procedures performed during this operating room shutdown (ORS) were logged, as well as those 4 weeks before (PRE) and 4 weeks after (POST) for comparison.

Results

A total of 2,475 cases were included in our analysis, with 754 occurring during shutdown. Overall case numbers dropped significantly during ORS and increased during recovery (mean 245.0 ± 28.4 PRE versus 58.0 ± 30.9 ORS versus 186.0±19.4 POST cases/wk, P< 0.001). Emergency cases predominated during ORS (26.4% PRE versus 59.3% ORS versus 31.5% POST, P< 0.001) despite decreasing in frequency (mean 64.5 ± 7.9 PRE versus 34.4 ± 12.1 ORS versus 58.5 ± 4.0 POST cases/wk, P< 0.001). Open surgeries remained constant in all three phases (52.2-54.1%), whereas laparoscopic and robotic surgeries decreased (-3.4% and -3.0%, P< 0.001). General and/or vascular surgery, urology, and neurosurgery comprised a greater proportion of caseload (+9.5%, +3.0%, +2.8%), whereas orthopedics, gynecology, and otolaryngology/plastic surgery all decreased proportionally (-5.0%, -4.4%, -5.9%, P< 0.001).

Conclusion

Operative volume significantly decreased during the SARS-CoV-2 outbreak. Emergency cases predominated during this time, although there were fewer emergency cases overall. General/vascular surgery became the most active service and open surgeries became more common. This reallocation of resources may be useful for future crisis planning among community hospitals.

Utility of d-dimer for diagnosis of deep vein thrombosis in coronavirus disease-19 infection

Objective

The objective of this study was to investigate the clinical usefulness of d-dimer in excluding a diagnosis of deep vein thrombosis (DVT) in patients with coronavirus disease (COVID-19) infection, potentially limiting the need for venous duplex ultrasound examination.

Methods

We retrospectively reviewed consecutive patients admitted to our institution with confirmed COVID-19 status by polymerase chain reaction between March 1, 2020, and May 13, 2020, and selected those who underwent both d-dimer and venous duplex ultrasound examination. This cohort was divided into two groups, those with and without DVT based on duplex ultrasound examination. These groups were then compared to determine the value of d-dimer in establishing this diagnosis.

Results

A total of 1170 patients were admitted with COVID-19, of which 158 were selected for this study. Of the 158, there were 52 patients with DVT and 106 without DVT. There were no differences in sex, age, race, or ethnicity between groups. Diabetes and routine hemodialysis were less commonly seen in the group with DVT. More than 90% of patients in both groups received prophylactic anticoagulation, but the use of low-molecular-weight heparin or subcutaneous heparin prophylaxis was not predictive of DVT. All patients had elevated acute-phase d-dimer levels using conventional criteria, and 154 of the 158 (97.5%) had elevated levels with age-adjusted criteria (mean d-dimer 16,163 ± 5395 ng/mL). Those with DVT had higher acute-phase d-dimer levels than those without DVT (median, 13,602 [interquartile range, 6616-36,543 ng/mL] vs 2880 [interquartile range, 1030-9126 ng/mL], P < .001). An optimal d-dimer cutoff of 6494 ng/mL was determined to differentiate those with and without DVT (sensitivity 80.8%, specificity 68.9%, negative predictive value 88.0%). Wells DVT criteria was not found to be a significant predictor of DVT. Elevated d-dimer as defined by our optimal metric was a statistically significant predictor of DVT in both univariate and multivariable analyses when adjusting for other factors (odds ratio, 6.12; 95% confidence interval, 2.79-13.39; P < .001).

Conclusions

d-dimer levels are uniformly elevated in patients with COVID-19. Although standard predictive criteria failed to predict DVT, our analysis showed a d-dimer of less than 6494 ng/mL may exclude DVT, potentially limiting the need for venous duplex ultrasound examination.

Lung clearance index is elevated in young children with symptom-controlled asthma

BACKGROUND

Pulmonary function testing has been recommended as an adjunct to symptom monitoring for assessment of asthma control. Lung clearance index (LCI) measures ventilation inhomogeneity and is thought to represent changes in the small airways. It has been proposed as a useful early marker of airway disease in asthmatic subjects, and determining it is feasible in preschool children. This study aims to assess whether LCI remains elevated in symptomatically controlled asthmatic children with a history of severe asthma, compared with healthy controls. A secondary aim was to determine whether the results were consistent across the preschool and school-aged populations.

METHODS

Using a case-control design, we compared 33 children with currently well-controlled symptoms who had a history of severe asthma, to 45 healthy controls (age 3-15 years) matched by age, height, and sex. We performed multiple breath washout tests using sulfur hexafluoride as a tracer gas, to determine their LCI and Scond values.

RESULTS

In the overall study, LCI z-score values were on average 0.86 units (95% confidence interval: 0.24-1.47, P = 0.01, t-test) higher in children with a history of severe asthma with current well-controlled symptoms compared with healthy controls. In addition, within the subgroup of preschool children (age ≤ 6), the asthmatic had significantly higher LCI z-score values than their healthy controls peers (mean (SD), 0.57 (2.18) vs -1.10 (1.00), P = 0.03, t-test). Twenty-seven percent (27%; 9/33) of subjects had an LCI value greater than the upper limit of our healthy controls despite being symptom controlled. Amongst preschool children, 5 (42%; 5/12) of the asthmatic children had abnormal LCI at the individual level.

CONCLUSIONS

LCI is elevated in children with asthma, which may be driven by differences in the preschool population. LCI may be useful in defining preschool asthma endotypes with persistent ventilation inhomogeneity despite symptomatic control.

Activation of liver X receptor reduces global ischemic brain injury by reduction of nuclear factor-kappaB

Recent studies have found that liver X receptors (LXRs) agonists decrease brain inflammation and exert neuroprotective effect. The aim of this study was to examine the mechanisms of action of liver X receptor agonist GW3965 against brain injury following global cerebral ischemia in the rat. The 48 male SD (Sprague-Dawley) rats were randomly partitioned into three groups: sham, global ischemia (4-vessel occlusion for 15 min; 4VO) treated with vehicle and global ischemia treated with GW3965 (20 mg/kg, via i.p. injection at 10 min after reperfusion). The functional outcome was determined by neurological evaluation at 24 h post ischemia and by testing rats in T maze at 3 and 7 days after reperfusion. The rats' daily body weight, incidence of seizures and 72 h mortality were also determined. After Nissl staining and TUNEL in coronal brain sections, the numbers of intact and damaged cells were counted in the CA1 sector of the hippocampus. The expression of phosphorylated inhibitor of kappaB (p-IkappaBalpha), nuclear factor-kappaB (NF-kappaB) subunit p65, and cyclo-oxygenase-2 (COX-2) were analyzed with Western blot at 12 h after reperfusion. GW3965 tended to reduce 72 h mortality and the incidence of post-ischemic seizures. GW3965-treated rats showed an improved neuronal survivability in CA1 and a significant increase in the percentage of spontaneous alternations detected in T-maze on day 7 after ischemia. GW3965-induced neuroprotection was associated with a significant reduction in nuclear translocation of NF-kB p65 subunit and a decrease in the hippocampal expression of NF-kB target gene, COX-2. LXR receptor agonist protects against neuronal damage following global cerebral ischemia. The mechanism of neuroprotection may include blockade of NF-kappaB activation and the subsequent suppression of COX-2 in the post ischemic brain.

Microarray-based compendium of hepatic gene expression profiles for prototypical ADME gene-inducing compounds in rats and mice in vivo

To examine species-specific aspects of the induction of absorption, distribution, metabolism and excretion (ADME)-related genes, we used 25 000 gene oligonucleotide microarrays to construct a rodent gene-response compendium that compared hepatic gene expression profiles and developed consensus aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR) and pregnane X-receptor (PXR) ligand signatures relevant to drug clearance. Twenty-six inducer compounds were chosen from the literature. Rats and mice received one of six dose levels (log2 dose escalation, 32-fold dose range) of each compound daily for 3 days. Animals were necropsied 6-9 h after the last dose, and tissues were collected for RNA analysis. Hepatic gene expression profiles were obtained using Rosetta Resolver expression analysis system, and ADME-related genes were extracted. Cross-talk among nuclear receptors or hepatoxicity at high dose levels resulted in large signatures (usually >1000 genes at p < 0.01) for most compounds. After ADME gene transcript enrichment, agglomerative clustering separated AhR ligands from CAR/PXR ligands, but it was difficult to distinguish CAR from PXR ligands. Consensus signatures were derived from groups of AhR, CAR and PXR ligands; and cross-talk among responding genes was determined. Many compounds had distinct log dose-response profiles, and relative potencies for ligands were established. Robust responses by CYP1A1, CYP2B10 (CAR responsive in mice) and CYP2B15 (CAR responsive in rats) and CYP3A1 (PXR responsive in rats) were used to benchmark the relative potency of different ligands and to determine the relative selectivity for AhR, CAR or PXR. By using a compendium of gene expression profiles, we defined species-specific induction patterns across the ADME transcriptome.

Connective tissue growth factor is a biomarker and mediator of kidney allograft fibrosis

Chronic allograft nephropathy (CAN) is a leading cause of kidney graft failure following transplantation. Its causes are complex and include both immunological and nonimmunological factors. Here we have studied the development of CAN in a mouse model of kidney transplantation comparing isografts and allografts. Unlike the normal histology and normal serum creatinine of the uninephrectomized, nonrejecting isografted mice (0.219 +/- 0.024 mg/dL), allografted mice demonstrated severe renal dysfunction (mean serum creatinine 0.519 +/- 0.061 mg/dL; p < 0.005) with progressive inflammation and fibrosis of the kidney. These animals also showed an increased expression of connective tissue growth factor (CTGF), both systemically and within the graft. CTGF was highly expressed in tubuloepithelial cells of allografts, along with alpha-smooth muscle actin, a marker of myofibroblasts, and transcriptionally associated with other markers of fibrosis. In vitro studies of tubular epithelium indicate that CTGF is capable of inducing EMT, independent of TGF-beta. Finally, in human transplant recipients, serum and urine CTGF levels are significantly elevated compared to naïve individuals. Urinary levels correlated with the histological presence of CAN. These studies suggest a critical role of CTGF in graft fibrogenesis, for both mouse and man. Thus, CTGF has potential as a biomarker of CAN, and also a therapeutic target in managing graft fibrosis.

Identification of potential pharmacological and toxicological targets differentiating structural analogs by a combination of transcriptional profiling and promoter analysis in LS-180 and Caco-2 adenocarcinoma cell lines

Detecting and understanding the potential for off-target pharmacological effects is critical in the optimization of lead compounds in drug discovery programs. Compound-mediated activation of the pregnane X receptor (PXR; NR1I2), a key regulator for drug metabolism genes, is often monitored to avoid potential drug-drug interactions. Two structural analogs, MRL-1 and MRL-2, were determined to be equivalent PXR activators in trans-activation assays. To differentiate these two PXR activators, their transcriptional effects were examined in PXR-sufficient (LS180) and PXR-deficient (Caco-2) adenocarcinoma cell lines. Both compounds regulated drug-management genes (e.g. CYP3A4, CYP2B6, UGT1A1 and ABCB1) in LS180 cells, but not in PXR-deficient Caco-2 cells. The potency of MRL-1 and MRL-2 on PXR activation was again equivalent as revealed by a set of 113 genes that were regulated by four prototypical PXR agonists (rifampicin, ritonavir, troglitazone and dexamethasone) in the LS180 cells. The specificity of the PXR signature genes was supported by the enrichment of putative PXR binding sites uncovered by sequence-based promoter analyses. Interestingly, an additional off-target activity of MRL-2 was suggested where sterol response element binding protein binding sites were found enriched in a subset of PXR signature genes. These genes, involved in cholesterol and fatty acid synthesis, were significantly regulated by ritonavir, chlorpromazine and MRL-2, which were linked to the manifestation of phospholipidosis. The present study demonstrates the utility of our approach in the differentiation and selection of lead compounds for drug development.

Profiling the hepatic effects of flutamide in rats: a microarray comparison with classical aryl hydrocarbon receptor ligands and atypical CYP1A inducers

The antiandrogen flutamide (FLU) is used primarily for prostate cancer and is an idiosyncratic hepatotoxicant that sometimes causes severe liver problems. To investigate FLU's overt hepatic effects, especially on inducible drug clearance-related gene networks, FLU's hepatic gene expression profile was examined in female Sprague-Dawley rats using approximately 22,500 oligonucleotide microarrays. Rats were dosed daily for 3 days with FLU at 500, 250, 62.5, 31.3, and 15.6 mg/kg/day, and hepatic RNA was isolated. FLU resulted in the dose-dependent regulation of approximately 350 genes. Employing a gene-response compendium, FLU was compared with three classical aryl hydrocarbon receptor (AhR) ligands, 3-methylcholanthrene, benzo[a]pyrene, and beta-naphthoflavone, and four atypical CYP1A inducers, indole-3-carbinol (I3C), omeprazole (OME), chlorpromazine (CPZ), and clotrimazole (CLO). The FLU gene response was comparable with classical AhR ligands across a signature AhR ligand gene set that included CYP1A1 and other members of the AhR gene battery. Dose-related responses of CYP1 genes established a maximum response ceiling and discerned potency differences in atypical inducers. FLU had a sharp down-regulation of c-fos that was comparable with all the compounds except CPZ and CLO. FLU absorption, distribution, metabolism, and excretion (ADME) gene expression analysis revealed that FLU, as well as I3C and OME, induced CYP2B and CYP3A, distinguishing them from the classical AhR ligands. By using a compendium of gene expression profiles, FLU was shown to signal in rats similar to an AhR activator with additional CYP2B and CYP3A effects that most resembled the ADME gene expression pattern of the atypical CYP1A inducers I3C and OME.

Innate immune response to encephalomyocarditis virus infection mediated by CD1d

CD1d-reactive natural killer T (NKT) cells can rapidly produce T helper type 1 (Th1) and/or Th2 cytokines, can activate antigen-presenting cell (APC) interleukin-12 (IL-12) production, and are implicated in the regulation of adaptive immune responses. The role of the CD1d system was assessed during infection with encephalomyocarditis virus (EMCV-D), a picornavirus that causes acute diabetes, paralysis and myocarditis. EMCV-D resistance depends on IL-12-mediated interferon-gamma (IFN-gamma) production. CD1d-deficient mice, which also lack CD1d-reactive NKT cells, were substantially more sensitive to infection with EMCV-D. Infected CD1d knockout mice had decreased IL-12 levels in vitro and in vivo, and indeed were protected by treatment with exogenous IL-12. IFN-gamma production in CD1d knockout mice was decreased compared with that in wild-type (WT) mice in response to EMCV-D in vitro, although differences were not detected in vivo. Treatment with anti-asialo-GM1 antibody, to deplete NK cells, caused a marked increase in susceptibility of WT mice to EMCV-D infection, whereas CD1d knockout mice were little affected, suggesting that NK-cell-mediated protection is CD1d-dependent. Therefore, these data indicate that CD1d is essential for optimal responses to acute picornaviral infection. We propose that CD1d-reactive T cells respond to early immune signals and function in the innate immune response to a physiological viral infection by rapidly augmenting APC IL-12 production and activating NK cells.

Cutting edge: Compartmentalization of Th1-like noninvariant CD1d-reactive T cells in hepatitis C virus-infected liver

Murine intrahepatic lymphocytes (IHL) are dominated by invariant TCR alpha-chain expressing CD1d-reactive NKT cells, which can cause model hepatitis. Invariant NKT (CD56(+/-)CD161(+)) and recently identified noninvariant CD1d-reactive T cells rapidly produce large amounts of IL-4 and/or IFN-gamma and can regulate Th1/Th2 responses. Human liver contains large numbers of CD56(+) NKT cells but few invariant NKT. Compared with matched peripheral blood T cell lines, primary IHL lines from patients with chronic hepatitis C had high levels of CD161 and CD1d reactivity, but the invariant TCR was rare. CD1d-reactive IHL were strikingly Th1 biased. IHL also demonstrated CD1d-specific cytotoxic activity. Hepatocytes and other liver cells express CD1d. These results identify a novel population of human T cells that could contribute to destructive as well as protective immune responses in the liver. CD1d-reactive T cells may have distinct roles in different tissues.

A major fraction of human bone marrow lymphocytes are Th2-like CD1d-reactive T cells that can suppress mixed lymphocyte responses

Murine bone marrow (BM) NK T cells can suppress graft-vs-host disease, transplant rejection, and MLRs. Human BM contains T cells with similar potential. Human BM was enriched for NK T cells, approximately 50% of which recognized the nonpolymorphic CD1d molecule. In contrast to the well-characterized blood-derived CD1d-reactive invariant NK T cells, the majority of human BM CD1d-reactive T cells used diverse TCR. Healthy donor invariant NK T cells rapidly produce large amounts of IL-4 and IFN-gamma and can influence Th1/Th2 decision-making. Healthy donor BM CD1d-reactive T cells were Th2-biased and suppressed MLR and, unlike the former, responded preferentially to CD1d(+) lymphoid cells. These results identify a novel population of human T cells which may contribute to B cell development and/or maintain Th2 bias against autoimmune T cell responses against new B cell Ag receptors. Distinct CD1d-reactive T cell populations have the potential to suppress graft-vs-host disease and stimulate antitumor responses.

Loss of IFN-gamma production by invariant NK T cells in advanced cancer

Invariant NK T cells express certain NK cell receptors and an invariant TCRalpha chain specific for the MHC class I-like CD1d protein. These invariant NK T cells can regulate diverse immune responses in mice, including antitumor responses, through mechanisms including rapid production of IL-4 and IFN-gamma, but their physiological functions remain uncertain. Invariant NK T cells were markedly decreased in peripheral blood from advanced prostate cancer patients, and their ex vivo expansion with a CD1d-presented lipid Ag (alpha-galactosylceramide) was diminished compared with healthy donors. Invariant NK T cells from healthy donors produced high levels of both IFN-gamma and IL-4. In contrast, whereas invariant NK T cells from prostate cancer patients also produced IL-4, they had diminished IFN-gamma production and a striking decrease in their IFN-gamma:IL-4 ratio. The IFN-gamma deficit was specific to the invariant NK T cells, as bulk T cells from prostate cancer patients produced normal levels of IFN-gamma and IL-4. These findings support an immunoregulatory function for invariant NK T cells in humans mediated by differential production of Th1 vs Th2 cytokines. They further indicate that antitumor responses may be suppressed by the marked Th2 bias of invariant NK T cells in advanced cancer patients.

CD1d-reactive T-cell activation leads to amelioration of disease caused by diabetogenic encephalomyocarditis virus

A subset of CD161 (NK1) T cells express an invariant Valpha14Jalpha281 TCR-alpha chain (Valpha(invt) T cells) and produce Th2 and Th1 cytokines rapidly in response to CD1d, but their physiological function(s) remain unclear. We have found that CD1d-reactive T cells mediate to resistance against the acute, cytopathic virus diabetogenic encephalomyocarditis virus (EMCV-D) in relatively Th1-biased, C57BL/6-based backgrounds. We show now that these results generalize to Th2-biased, hypersensitive BALB/c mice. CD1d-KO BALB/c mice were more susceptible to EMCV-D. Furthermore, alpha-galactosylceramide (alpha-GalCer), a CD1d-presented lipid antigen that specifically activates Valpha(invt) T cells, protected wild-type (WT) mice against EMCV-D-induced encephalitis, myocarditis, and diabetes. In contrast, neither CD1d-KO nor Jalpha281-KO mice were protected by alpha-GALCER: Finally, disease in Jalpha281-KO mice was comparable to WT, indicating for the first time equivalent roles for CD1d-reactive Valpha(invt) and noninvariant T cells in resistance to acute viral infection. A model for how CD1d-reactive T cells can initiate immune responses, which synthesizes current results, is presented.

Taurocholate stimulates transcytotic vesicular pathways labeled by horseradish peroxidase in the isolated perfused rat liver

The effect of taurocholate on transcytotic vesicular pathways labeled with horseradish peroxidase was assessed in isolated perfused rat liver preparations. Forty-five minutes after a horseradish peroxidase load in a recirculating system, continuous infusion of taurocholate but not taurodehydrocholate significantly increased horseradish peroxidase excretion in bile by 50% compared with controls. When horseradish peroxidase (25 mg) was pulse loaded for 1 minute in control perfusions, it appeared in bile in early (4-6 minutes) and late (20-25 minutes) peaks, the latter accounting for 90% of total horseradish peroxidase output. Taurocholate infusion significantly increased horseradish peroxidase output in both early and late peaks, whereas only a small increase in the early peak was observed with taurodehydrocholate. Colchicine pretreatment increased the early peak in bile but abolished the second peak. Electron micrographs from control livers revealed the accumulation of horseradish peroxidase-containing vesicles in pericanalicular regions at early (2 minutes) as well as late (18 minutes) periods. When a morphometric analysis of electron micrographs was performed from pericanalicular regions 2 minutes after a 1-minute pulse of horseradish peroxidase (500 mg), taurocholate but not taurodehydrocholate increased both the density and percent area of horseradish peroxidase-containing vesicles compared with controls. In contrast, colchicine pretreatment had no effect on the density of the early-appearing vesicles, although their individual sizes were reduced. Taurocholate but not taurodehydrocholate also increased the percent of tubular structures in the pericanalicular region. These findings indicate that taurocholate stimulates both early and late transcytotic vesicle pathways and therefore probably microtubule-independent vesicle pathway is present in hepatocytes that must be distinguished from paracellular routes.