3× multiplexed detection of antibiotic resistant plasmids with single molecule sensitivity

Bacterial pathogens resistant to antibiotics have become a serious health threat. Those species which have developed resistance against multiple drugs such as the carbapenems, are more lethal as these are last line therapy antibiotics. Current diagnostic tests for these resistance traits are based on singleplex target amplification techniques which can be time consuming and prone to errors. Here, we demonstrate a chip based optofluidic system with single molecule sensitivity for amplification-free, multiplexed detection of plasmids with genes corresponding to antibiotic resistance, within one hour. Rotating disks and microfluidic chips with functionalized polymer monoliths provided the upstream sample preparation steps to selectively extract these plasmids from blood spiked with E. coli DH5α cells. Waveguide-based spatial multiplexing using a multi-mode interference waveguide on an optofluidic chip was used for parallel detection of three different carbapenem resistance genes. These results point the way towards rapid, amplification-free, multiplex analysis of antibiotic-resistant pathogens.

The fine structure of the neurons in the rat substantia nigra

Three distinct neurons were identified in the substantia nigra of the rat using Golgi, light, and electron microscopic techniques. A large neuron, found in the pars reticulata, is characterized by well-developed RER, a tubular cytoplasmic inclusion, and somatic and dendritic thorns. A medium-sized neuron, found in the pars compacta, has an eccentric nucleus, distinct Nissl bodies, and an inclusion composed of whorls of concentric cisternae. A small neuron, found in both nigral regions, contains a highly invaginated nucleus, fibrous nuclear inclusion, and paucity of cytoplasmic organelles. Its axon synapses around other nigral dendrites. The presence of these neurons was correlated with the efferent projections and function of the substantia nigra.

The impact of head injury neurobehavioural sequelae on personal relationships: Preliminary findings

BACKGROUND

Existing evidence suggests that neurobehavioural disability is a frequent legacy of serious head trauma and has a major impact on the psychological well-being of relatives and friends of people with brain injuries.

OBJECTIVE

To explore which neurobehavioural legacies of serious head trauma have the greatest impact on personal relationships and increase the risk of relationship breakdown.

METHOD

Forty-eight partners of people who had suffered serious head trauma were asked to complete a 12-item measure to rate how different neurobehavioural characteristics had adversely affected their relationship with the brain injured person. Twenty-three couples who had divorced or separated from their injured partner in the years following injury comprised the 'separated' group, 25 still in the relationship at the time data were collected comprised the 'together' group.

RESULTS

Even though many neurobehavioural characteristics of brain injury were reported by partners of both the separated and the together group as placing a strain on the relationship only mood swings accounted for a significant between groups difference [t(40.13) = 3.33, p = 0.002]. The magnitude of the difference in the means was large (712 = 0.19).

CONCLUSIONS

Unpredictable patterns of behaviour, as perceived by partners of brain injured individuals, impose the greatest burden on personal relationships and may contribute to relationship breakdown.

Psychosocial adjustment 17 years after severe brain injury

OBJECTIVES

To examine very long term psychosocial outcome following severe brain injury in a large cohort, with the aim of evaluating Thomsen's observation that even after very serious head trauma the long term outcome in some patients is reasonably good.

METHODS

The cohort consisted of 80 patients who had suffered severe brain injury evaluated at a mean time of 17 years post injury (range 10-32 years). Information regarding employment status and relationship status was obtained during clinical interview. Psychosocial outcome measures included the Supervision Rating Scale, Satisfaction with Life Scale, Hospital Anxiety and Depression Scale (HADS), Patient Competency Rating Scale, and Community Integration Questionnaire.

RESULTS

Of the cohort, 72.0% lived independently, 28.7% were in full time employment, and 60.0% were married or cohabiting. The mean rating of life satisfaction was "slightly dissatisfied", but no serious emotional problems were evident from self report ratings on the HADS. Mean functional competency ratings and community integration levels were just below those reported for non-disabled patients.

CONCLUSIONS

Results indicate that although long term psychosocial functioning in patients with severe head injury remains compromised, long term adjustment may be better than expected from data reported by studies assessing psychosocial outcome at earlier stages of recovery.

Evaluation of the specificities of five DNA amplification methods for the detection of Neisseria gonorrhoeae

The intragenus specificities of five molecular diagnostic methods for Neisseria gonorrhoeae were determined. Three assays were considered suboptimal. Molecular detection of N. gonorrhoeae from sites where other Neisseria spp. commonly occur or from any site in low-prevalence settings should be confirmed by a test targeting a different genetic locus.

Autologous lacrimal-lymphoid mixed-cell reactions induce dacryoadenitis in rabbits

Autoimmune dacryoadenitis, such as occurs in Sjögren's syndrome, is a frequent cause of lacrimal insufficiency, which in turn can cause dry eye. Rabbits are used frequently to test ocular therapies. Our goal is to develop a rabbit model of autoimmune dacryoadenitis to identify and test candidate therapies. Our approach arises from the observations that lacrimal gland epithelial cells stimulate proliferation in cultured autologous lymphocyte preparations and that an anti-MHC II antibody blocks this proliferation. The purpose of this study was to determine if injecting this proliferating autologous mixed cell reaction could induce dacryoadenitis in rabbits. After establishing that irradiated lacrimal gland epithelial cells stimulate proliferation in autologous peripheral blood lymphocytes, irradiated cells from a single lacrimal gland were co-cultured with autologous lymphocytes and after 5 days the mixed cell reaction, or components of the reaction, were injected into the contralateral lacrimal gland of the donor rabbit. After 2 weeks, the injected glands were removed and lymphocytic infiltration quantitated using digital image analysis of immunostained histological sections. Injecting an autologous mixed cell reaction of co-cultured irradiated lacrimal gland epithelial cells and lymphocytes reliably induced abundant periductal foci of >200 lymphocytes expressing CD18 and/or a rabbit thymic lymphocyte antigen (RTLA). Injection of medium or autologous lymphocytes alone elicited little response; injections of lymphocytes cultured with lysates of lacrimal gland epithelial cells elicited variable, modest responses. These lysates did not stimulate proliferation in the mixed cell reaction and proliferation was not observed if a porous membrane separated co-cultured lacrimal gland cells and lymphocytes. The results demonstrate that injecting an autologous mixed cell reaction of lacrimal gland epithelial cells and lymphocytes reliably creates a model of autoimmune dacryoadenitis. The relative ineffectiveness of components of the reaction to do the same supports the hypothesis that lacrimal gland epithelial cells trigger or exacerbate lacrimal autoimmune disease by presentation of autoantigens via MHC II. This experimental system can aid efforts to further understand mechanisms of diseases, and to identify and test candidate therapies.

Lacrimal gland epithelial cells stimulate proliferation in autologous lymphocyte preparations

Autoimmune dacryoadenitis is a frequent cause of lacrimal insufficiency. In order to test hypotheses regarding mechanisms that can trigger this syndrome, we developed a method to obtain a preparation of rabbit lacrimal gland epithelial cells essentially free of immune-system cells. The method relies on controlled digestion to disperse lacrimal acini, and recovers acini by filtration through various sizes of nylon mesh. Purity and integrity of the preparation were established qualitatively using light and electron microscopy. Contamination by immune-system cells was quantitated by immunohistochemistry using anti-CD18, and -RTLA (rabbit thymic lymphocyte antigen) antibodies. The novel method produced preparations of highly-purified lacrimal gland epithelial cells (pLGEC) with expected morphological characteristics with less than 1.5% of the cells staining for CD18 or RTLA. The method also yielded preparations of lacrimal gland interstitial cells (LGIC) enriched for lymphocytes; in these preparations either CD18 or RTLA were detected on nearly 10% of the cells. pLGEC promoted proliferation in preparations of autologous splenic lymphocytes (SPL) that was blocked by anti-MHC class II but not anti-MHC class I antibodies. This observation, combined with the apparent requirement that pLGEC must contact the autologous lymphocyte preparation to promote proliferation, supports the hypothesis the proliferation arises from antigen-presentation via MHC class II by pLGEC.

Sjögren's autoimmunity: how perturbation of recognition in endomembrane traffic may provoke pathological recognition at the cell surface

CD4 T cell antigen recognition requires presentation by major histocompatibility complex Class II molecules (MHC II). B cell surface immunoglobulins recognize antigens independently of MHC II, but activation typically requires CD4 cell cytokines as accessory signals. Plasma membrane-endomembrane traffic in lacrimal gland acinar cells, targets of autoimmune activity in Sjögren's syndrome, may satisfy both requirements. The Golgi protein galactosyltransferase and the lysosomal proteins cathepsin B and cathepsin D appear at the plasma membranes during sustained secretomotor stimulation. The RNA transcription termination factor La, a frequent target of Sjögren's autoantibodies, appears in the acinar cell cytoplasm and plasma membranes during viral infection and during in vitro exposure to cytokines. MHC II cycle through endomembrane compartments which contain La, galactosyltransferase, cathepsin B and cathepsin D and which are sites of proteolysis. This traffic may permit trilateral interactions in which B cells recognize autoantigens at the surface membranes, CD4 T cells recognize peptides presented by MHC II, B cells provide accessory signals to CD4 T cells, and CD4 T cells provide cytokines that activate B cells. Acinar cells stimulate lymphocyte proliferation in autologous mixed cell reactions, confirming that they are capable of provoking autoimmune responses.

Stimulation with carbachol alters endomembrane distribution and plasma membrane expression of intracellular proteins in lacrimal acinar cells

The events that lead to Sjögren's autoimmune processes in the lacrimal gland remain poorly understood. The acinar cell's responses to acute cholinergic stimulation include release of secretory products across the apical plasma membrane (apm) and a number of processes related to traffic between endomembrane compartments and the basal-lateral plasma membranes (blm), such as recruitment of Na, K-ATPase, accelerated recycling, and accelerated transcytosis of secretory IgA. We tested the hypothesis that stimulation-induced acceleration of endomembrane traffic is accompanied by changes in compartmentation and increased blm expression of proteins that are normally sequestered in endomembrane compartments. Isolated rabbit lacrimal gland acinar cells were cultured in serum-free media for 2 days. After harvesting, cells were incubated with or without 10 microm carbachol at 37 degrees C for 20 min. Cells were lysed, and lysates were analysed by isopycnic centrifugation on sorbitol gradients. Galactosyltransferase catalytic activity was determined biochemically. Different forms of cathepsin B were detected by Western blotting. Carbachol stimulation decreased the contents of beta-hexosaminidase, alpha-glucosidase, and protein in secretory vesicles and increased them in specific compartments of the trans-Golgi network (ld-tgns). Stimulation also caused levels of galactosyltransferase, preprocathepsin B, and procathepsin B to increase two- to three-fold in the blm as well as increasing in the ld-tgns. Other changes caused by sustained stimulation included: (a) increased levels of protein and procathepsin B in compartments of the lysosomal pathway; (b) changes in the distributions of Rab5 within the endomembrane system; (c) changes in the distribution of Rab6 within the Golgi complex and tgn; (d) decreased expression of acid phosphatase and MHC class II molecules in the blm; and (e) decreased total content of Na,K-ATPase, which appeared to have been selectively depleted from the tgn and blmre. We propose that the normal compartmentation of certain proteins may allow them to remain cryptic, such that they are not subject to central tolerance. Stimulation-induced increases in the levels expressed at the blm or secreted to the interstitium may, therefore, contribute to initiation of local autoimmune responses.

MHC class II molecules, cathepsins, and La/SSB proteins in lacrimal acinar cell endomembranes

Sjögren's syndrome is a chronic autoimmune disease affecting the lacrimal glands and other epithelia. It has been suggested that acinar cells of the lacrimal glands provoke local autoimmune responses, leading to Sjögren's syndrome when they begin expressing major histocompatibility complex (MHC) class II molecules. We used isopycnic centrifugation and phase partitioning to resolve compartments that participate in traffic between the basolateral membranes and the endomembrane system to test the hypothesis that MHC class II molecules enter compartments that contain potential autoantigens, i.e., La/SSB, and enzymes capable of proteolytically processing autoantigen, i.e., cathepsins B and D. A series of compartments identified as secretory vesicle membranes, prelysosomes, and microdomains of the trans-Golgi network involved in traffic to the basolateral membrane, to the secretory vesicles, and to the prelysosomes were all prominent loci of MHC class II molecules, La/SSB, and cathepsins B and D. These observations support the thesis that lacrimal gland acinar cells that have been induced to express MHC class II molecules function as autoantigen processing and presenting cells.

Prolactin and prolactin receptors in the lacrimal gland

Light and electron microscopic immunocytochemistry, in situ hybridization and Dot Blot analysis revealed intracellular localization of prolactin-like molecules and prolactin mRNA in epithelial cells of the lacrimal glands of rabbits. There was also positive immunostaining for prolactin receptors on acinar cells and some interstitial cells. On Western blots of homogenates of whole lacrimal gland, isolated lacrimal acinar cells, isolated lacrimal interstitial cells and peripheral blood lymphocytes, prolactin antibody consistently labeled protein bands migrating at approximately 36 and 50 kD. These data confirm that lacrimal gland acinar cells produce endogenous prolactin-like molecules, but also express prolactin receptors. Since prolactin immunoreactivity has been detected in tear fluid and we found no accumulations of immunogold label in endocytic or transport vesicles, we hypothesize that the prolactin-like molecules in tear fluid originate primarily from synthesis within the acinar cells. We hypothesize further that prolactin from pituitary and other non-acinar cell origin has a modulating influence on acinar cell activity as well as immune function in the lacrimal gland, and that some of the prolactin-like molecules produced by the acinar cells contribute to these functions by autocrine/paracrine mechanisms.

Androgen influence on lacrimal gland apoptosis, necrosis, and lymphocytic infiltration

PURPOSE

Previous studies have shown that ovariectomy and hypophysectomy cause regression of the lacrimal gland and have implicated androgens as trophic hormones that support the gland. The purposes of this study were to test the hypothesis that glandular regression after ovariectomy is due to apoptosis, to identify the cell type or types that undergo apoptosis, to survey the time course of the apoptosis, and to determine whether ovariectomy-induced apoptosis could be prevented by dihydrotestosterone (DHT) treatment.

METHODS

Groups of sexually mature female New Zealand White rabbits were ovariectomized and killed at various time periods up to 9 days. Additional groups of ovariectomized rabbits were treated with 4 mg/kg DHT per day. At each time period, sham-operated rabbits were used as controls. Lacrimal glands were removed and processed for analysis of apoptosis as assessed by DNA fragmentation and for morphologic examination. DNA fragmentation was determined using the TdT-dUTP terminal nick-end labeling assay and by agarose gel electrophoresis. Labeled nuclei were quantified by automated densitometry. Sections were also stained for RTLA (rabbit thymic lymphocyte antigen), rabbit CD18, and La antigen. Morphology was evaluated by both light and electron microscopy.

RESULTS

The time course of apoptosis exhibited two phases, a rapid and transient phase and a second prolonged phase. A transient phase peaked at approximately 4 to 6 hours after ovariectomy. The values for degraded DNA as a percentage of total nuclear area were 4.29%+/-0.79% and 4.26%+/-0.54%, respectively. The values for sham-operated controls examined at the same time periods were 1.77%+/-0.08% and 0.82%+/-0.21%, respectively. The percentage of degraded DNA at 24 hours after ovariectomy was not different from controls examined at the same interval after sham operation. The percentage of degraded DNA 6 days after ovariectomy was significantly increased (8.5%+/-2.4%), compared with sham-operated animals at the same time period (0.68%+/-0.03%). DNA laddering was more pronounced after ovariectomy. Dihydrotestosterone treatment in ovariectomized rabbits suppressed the increase in DNA degradation. Morphologic examination of lacrimal gland sections indicated that ovariectomy caused apoptosis of interstitial cells rather than acinar or ductal epithelial cells. Tissue taken 4 hours and 6 days after ovariectomy showed nuclear chromatin condensation principally in plasma cells. Increased numbers of macrophages were also evident. Significant levels of cell degeneration and cell debris, characteristic of necrosis, were observed in acinar regions 6 days after ovariectomy. Dihydrotestosterone prevented this necrosis. Increased numbers of RTLA+, CD18+, and La+ interstitial cells were also evident 6 days after ovariectomy. In addition, ovariectomy increased La expression in ductal cells. Dihydrotestosterone treatment prevented the increase in numbers of lymphoid cells and La expression. Dihydrotestosterone also promoted the appearance of mitotic figures in acinar cells and increased the sizes of acini by 43% (P < 0.05).

CONCLUSIONS

Glandular atrophy observed after ovariectomy is likely to proceed by necrosis of acinar cells rather than apoptosis. This process begins with an apparent time lag after a rapid phase of interstitial cell apoptosis. These processes are accompanied by increased lymphocytic infiltration. These results suggest that a critical level of androgen is necessary to maintain lacrimal gland structure and function and that a decrease in available androgen below this level could trigger lacrimal gland apoptosis and necrosis, and an autoimmune response. Because apoptotic and necrotic cell fragments may be sources of autoantigens that can be processed and presented to initiate an autoimmune reaction, we surmise that cell death triggered by androgen withdrawal may trigger an autoimmune response such as that encountered in Sjögren's syndrome. (ABSTRACT TRUNCATED)

Clinical and cost effectiveness of post-acute neurobehavioural rehabilitation

The value of post-acute, community based social and behavioural rehabilitation for people with serious neurobehavioural disability has been the subject of a dispute for a number of years. Some authorities doubt that major changes in social adaptability and independence is possible several years post-injury. This paper attempts to assess both the clinical and cost effectiveness of such rehabilitation on a group who have suffered serious brain injury and display behaviour problems and cognitive deficits which prevent them living as independent members of the community. The discharge and follow-up data on 76 people who have received rehabilitation indicates that, with a minimum of 6 months rehabilitation, many severely damaged individuals can progress to less dependent placements in the community, and maintain higher levels of social activity (independence) with fewer hours of care support. This can amount to a per capita lifetime reduction of over 1 million pounds per annum in the cost of supporting such people in the community. Time between injury and the beginning of rehabilitation is a factor influencing outcome but longer periods of rehabilitation (beyond 12 months for the most seriously disabled) is not associated with a better outcome, measured by a reduction in care hours. The cost effectiveness of rehabilitation is greater for those who receive treatment within 2 years of injury. However, those who received rehabilitation at later stages also achieved significant social outcomes and savings on care hours.

Characterization and optimization of in vitro assay conditions for (1,3)beta-glucan synthase activity from Aspergillus fumigatus and Candida albicans for enzyme inhibition screening

(1,3)Beta-D-glucan synthase (E.C.2.4.1.34. UDP-glucose: 1,3-beta-D-glucan 3-beta-glucosyl transferase) catalyzes the polymerization of glucose ([1-3]-beta-linkages) using UDP-glucose as substrate. We have determined optimal in vitro conditions for the assay of (1,3)beta-glucan synthase activity from Aspergillus fumigatus and Candida albicans. These included lysis of cells in the following for C. albicans, 100 mM HEPES, pH 8.0, 10 microM guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS), 2 mM ethylenediaminetetraacetic acid (EDTA), disodium salt, 5 mM NaF, 250 mM sucrose, and 10 mM NaH2PO4; and for A. fumigatus, 50 mM HEPES, 10mM EDTA, 750 mM sucrose, 10 mM NaH2PO4, 100 mM cellobiose and 50 microM GTPgammaS. Resulting low-speed supernatants were used as enzyme sources to determine the optimal in vitro assay conditions. We have characterized the resulting enzyme activities and tested the optimized assays with known (1,3)beta-glucan synthase inhibitors including cilofungin, papulacandin, aculeacin A, and echinocandin B. We have used both optimized assays to screen > 1000 extracts of marine macroorganisms and, using bioassay-guided purification, have identified (1,3)beta-glucan synthase inhibitors.

A method to study induction of autoimmunity in vitro: co-culture of lacrimal cells and autologous immune system cells

Co-culturing autologous lacrimal gland cells and immune system cells can lead to spleen cell proliferation with a time course similar to that for proliferation in a typical heterologous MLR. Although these results are consistent with the hypothesis that lacrimal acinar cells are a source of antigen, and may or may not serve in part as an APC, future studies of this preparation are required to test these hypotheses. We are unaware of reports demonstrating that co-culturing control epithelial tissue and autologous splenic lymphocytes from apparently healthy animals leads to lymphocytic proliferation. Our results suggest that the appropriate co-culture of tissues and immune cells from healthy animals, perhaps such as detailed above, should help identify mechanisms contributing to the induction of autoimmune disease. Knowledge regarding such mechanisms should help efforts to prevent such disease, and perhaps reverse it.

Change in relationship status following traumatic brain injury

Previous studies have highlighted the burden placed on family members and close partners of individuals who have sustained traumatic brain injury. This burden of stress has been attributed to the neurobehavioural sequelae of such injuries. However, the extent to which brain injury affects marriages and close relationships has never been statistically evaluated. This study looked at 131 adults with traumatic brain injury in order to determine the incidence of divorce/separation; 49 per cent of our sample reported that they had divorced or separated from their partners during a 5-8-year period following brain injury. Factors which may predict the outcome of relationships include severity of injury (as determined by length of post-traumatic amnesia), length of relationship, and time since injury. The influence of these factors in determining the risk of relationship breakdown is discussed.

Inhibition of Neurospora crassa growth by a glucan synthase-1 antisense construct

We have used the filamentous fungus, Neurospora crassa, as a model system to test the concept that antisense targeting of the cell-wall assembly enzyme, (1,3)beta-glucan synthase [E.C. 2.4.1.34; UDPglucose: 1,3-beta-D-glucan 3-beta-D-glucosyltransferase], leads to a corresponding decrease in growth of the organism. Previously, our laboratory isolated a gene (glucan synthase-1, gs-1) that is required for (1,3)beta-glucan synthase activity. Wild-type cells were transformed with DNA vectors encoding various RNAs complementary to the gs-1 messenger RNA (antisense RNA) cloned downstream from an inducible promoter (quinic acid-2[qa-2p]). Stable transformants, expressing a partially inverted antisense message of gs-1 (pMYX107), exhibited dramatic reduction ingrowth compared with empty vector controls. Hyphal measurements of these transformants grown on race tubes indicated that all of the transformants showed various degrees of inhibition. Microscopic observations of transformants revealed shorter hyphal lengths when grown under conditions expressing antisense. Further characterization revealed that the specific activities of (1,3)beta-glucan synthase were decreased by as much as 63% relative to empty vector controls. Together, these observations suggest that antisense against (1,3)beta-glucan synthase led to a reduction in enzyme levels that resulted in altered cell-wall morphology and inhibition of growth. It is possible that antisense oligonucleotides against gs-1 may be useful antifungal agents.

Adenovirus infection of the cornea causes histopathologic changes in the lacrimal gland

PURPOSE

To explore the effects on the lacrimal gland of adenovirus infection of the cornea.

METHODS

Rabbit corneas were inoculated with human adenoviruses Ad5, Ad14, or a rabbit adapted form of Ad 5, and in some instances booster inoculations were given. Sections of lacrimal glands removed 21-59 days post-inoculation were immunostained using antibodies against rabbit Class I and Class II MHC molecules, CD4, CD8, CD18, and rabbit thymic lymphocyte antigen (RTLA). Relative numbers of positively stained cells were quantified with a Metamorph image analysis system.

RESULTS

RTLA and CD18 antigens were expressed on many interstitial cells in the normal lacrimal gland, but few expressed CD4 or CD8. The number of RTLA+ cells increased by 60-100% after inoculation of Ad5 and after boosting, and CD18+ cells increased from 33-100% after inoculation of Ad5 and after boosting. Booster inoculations also caused focal lymphocytic infiltration. MHC Class I was expressed on interstitial cells and duct epithelium, but not acinar cells, and there was no detectable difference after viral infection. In controls, MHC Class II was localized to a population of interstitial cells and a few acinar cells. A single inoculation of the Ad5 virus did not result in an increase in the total number of MHC Class II-positive cells at 21 days, but inoculation with the rabbit-adapted Ad 5 and booster inoculations caused a 30% increase.

CONCLUSIONS

Ad5 and rabbit-adapted Ad5 infection of the cornea induce lymphocytic infiltration in the lacrimal gland, and the effect is enhanced by boosting. There is also an increase in expression of MHC Class II after inoculation with rabbit-adapted Ad5 and with booster inoculations.

Na-K-ATPase in lacrimal gland acinar cell endosomal system: correcting a case of mistaken identity

Na-K-ATPase is associated with a variety of membrane populations in lacrimal acinar cells. Acinus-like structures formed by rabbit acinar cells in primary culture were incubated with horseradish peroxidase (HRP) to label basolateral and endosomal membranes and then analyzed by electron microscopy cytochemistry with the 3-3'-diaminobenzidine reaction or by fractionation and measurement of marker catalytic activities or immunoreactivities. HRP adsorbed to basolateral membranes at 4 degrees C. Fractionation showed it associated with low-density membranes enriched in acid phosphatase and TGN38 but containing only minor amounts of Na-K-ATPase. Cells internalized HRP to cytoplasmic vesicles, Golgi structures, and lysosomes at 37 degrees C. The major endosomal compartment revealed by fractionation coincided with major peaks of Na-K-ATPase and Rab6 and secondary peaks of galactosyltransferase and gamma-adaptin. Carbachol (10 microM) increased lysosomal and Golgi labeling. Thus most of the Na-K-ATPase is located in the basolateral membrane-oriented endosomal system, concentrated in a compartment possibly related to the trans-Golgi network. Constitutive and stimulation-accelerated traffic to and from this compartment may serve several exocrine cell functions.

Studies of adenovirus-induced eye disease in the rabbit model

PURPOSE

To achieve a better understanding of the pathogenic processes associated with human adenovirus (Ad)-induced ocular disease.

METHODS

Growth curves of Ad5 and Ad14 were performed in cell cultures derived from rabbit and human corneal epithelium (CE) and corneal keratocytes (CK). For in vivo studies, rabbit eyes were inoculated intrastromally and topically with 10(6) plaque-forming units per eye of Ad5 and ultraviolet light-inactivated (UV-1) Ad5 or Ad14, and the clinical features of the eyes were evaluated by biomicroscopic slit lamp examinations. Duration and quantitation of virus in tear samples were monitored. Humoral response was evaluated by enzyme-linked immunosorbent assay and serum neutralization titrations. Histopathologic and immunocytochemical staining of frozen corneal tissues was performed to determine the expression of major histocompatibility complex (MHC) class I and II and the presence of CD4+ and CD8+ T lymphocytes and CD18+ cells after the immunopathologic response elicited by virus inoculation.

RESULTS

Both Ad5 and Ad14 replicated in all human cell cultures studied. In cells of rabbit origin, Ad5 replicated in cultured CE and CK cells, whereas Ad14 replication appeared restricted. Virus titers in ocular samples from Ad5-inoculated eyes peaked on postinoculation days 3 through 4, with approximately a 100-fold increase in infectious virus in comparison to initial titers. The duration of Ad5 shedding was 8.9 +/- 2.4 days. Ad5, Ad5 UV-I, and Ad14 induced seroconversion and subepithelial opacities. CD4+ and CD8+ T lymphocytes and CD18+ cells were present in these intrastromal immune cell infiltrates. Expression of MHC class I and II was observed in keratocytes and immune cells; MHC class I also was expressed on CE cells in inflamed areas.

CONCLUSIONS

Ad5 is capable of replicating in both CE and CK cells of the rabbit eye. The presence of Ad antigens within the corneal stroma originating from infectious virus (Ad5), UV-inactivated virus (Ad5), or nonreplicating infectious virus (Ad14) can elicit indistinguishable immunopathologic responses in the stroma composed of CD4+, CD8+, and CD18+ cells.

Hypophysectomy-induced regression of female rat lacrimal glands: partial restoration and maintenance by dihydrotestosterone and prolactin

PURPOSE

Previous studies have implicated androgens and one or more as yet unknown pituitary or pituitary-dependent factors in the regulation of certain lacrimal gland functions. Many observations suggest that prolactin (PRL) might well be one of these factors. This study was designed to determine the effect of hypophysectomy on biochemical markers of exorbital lacrimal gland secretory capacity and to determine the extent to which dihydrotestosterone (DHT) and prolactin reverse these changes.

METHODS

Female rats were hypophysectomized and, 5 days later, were treated for 2 days with DHT (0.25 or 1 mg/kg), PRL (1 or 5 mg/kg), combinations of the low or high doses of DHT and PRL, or vehicle only. The animals were killed, and crude membrane fractions were isolated from their lacrimal glands. An untreated group served as control.

RESULTS

Lacrimal glands atrophied rapidly after hypophysectomy, losing 40% of their total and membrane-associated protein and 50% of their total DNA within 5 days. Total Na+,K(+)-ATPase and acid phosphatase activities and beta-adrenergic receptor number were decreased by half, whereas alkaline phosphatase activity and muscarinic cholinergic receptor number were reduced by 25% to 30%. DHT treatment increased total DNA above control values; it partially restored the amount of protein in the gland, the Na+,K(+)-ATPase and acid phosphatase activities, and the beta-adrenergic receptor number; and it fully restored the alkaline phosphatase activity. Prolactin treatment partially restored the amount of protein in the gland and the Na+,K(+)-ATPase activity; it fully restored the alkaline phosphatase activity and cholinergic receptor number; but it had no effect on the acid phosphatase activity or the beta-adrenergic receptor number. The high dose of DHT reduced the increase in cholinergic receptor number elicited by PRL. The high dose of PRL reduced the increases of total Na+,K(+)-ATPase and acid phosphatase elicited by DHT.

CONCLUSIONS

These findings suggest that DHT and PRL exert general trophic actions on the lacrimal gland and specifically on lacrimal Na+,K(+)-ATPase, acid phosphatase, and neurotransmitter receptors. They also suggest that excessive levels of either hormone may be deleterious to secretory function. Because sex hormone levels are prone to wide fluctuations in women, our results also suggest a plausible hypothesis to account for the greater incidence in women of lacrimal insufficiency.

Traffic of major histocompatibility complex class II molecules in rabbit lacrimal gland acinar cells

PURPOSE

It has been suggested that lacrimal gland acinar cells, which have been induced to express major histocompatibility complex class II (MHC II) molecules, might initiate local autoimmunity by using mechanisms similar to those operating in the specialized antigen-presenting cells to process and present autoantigens. Surface-labeling experiments indicate that constituents of the acinar cell plasma membrane participate in a rapid recycling traffic. The authors have surveyed the subcellular distribution of MHC II molecules and have evaluated their participation in the traffic between plasma membranes and intracellular compartments.

METHODS

Acinar cells were isolated from rabbit lacrimal glands and maintained for two nights in a serum-free, hormone-supplemented culture medium containing 10 microM carbachol. MHC II molecules were detected with a monoclonal antibody (MAB 2C4), biotinylated goat-antimouse IgG (BGAM), and avidin-ferritin (AvFe) or streptavidin-gold (SAvAu) conjugates.

RESULTS

Postembedding labeling with MAB 2C4, BGAM, and AvFe revealed MHC II molecules at the surface membranes, in cytoplasmic vesicles, and in secretory vesicles. When cells were chilled to 4 degrees C and subjected to preembedding labeling with MAB 2C4, BGAM, and AvFe, surface MHC II molecules were specifically labeled. Labeled complexes were rapidly internalized upon warming to 37 degrees C. Postembedding labeling with MAB 2C4, BGAM, and SAvAu revealed additional intracellular MHC II molecules, with a distribution overlapping that of the MHC II molecules labeled during the preembedding procedure. When cells were cultured overnight in the presence of MAB 2C4 and subjected to postembedding labeling with BGAM and AvFe, label was detectable in small vesicles and in secretory vesicles. However, the extent of labeling appeared less than obtained with postembedding labeling with MAB 2C4, BGAM, and AvFe. Preembedding labeling of cells that had been incubated overnight with MAB 2C4 indicated that the cells continued to express MHC II molecules at their surface membranes, and rapid internalization of label upon warming to 37 degrees C confirmed that MHC II molecule traffic continued in the presence of MAB 2C4. Postembedding labeling with MAB 2C4, BGAM, and SAvAu indicated the continued presence of a large intracellular pool of MHC II molecules.

CONCLUSIONS

MHC II molecules in lacrimal acinar cells are present in large intracellular and small surface pools. They move rapidly between these two pools, but further work will be required to determine whether the MHC II molecule traffic represents recycling or turnover and whether recycling pools and sequestered pools coexist. The presently available data make it reasonable to propose that the traffic of MHC II molecules to plasma membranes provides a mechanism by which acinar cells display intracellularly generated autoantigens to potentially reactive helper T lymphocytes.

Surface and intracellular pools of Na,K-ATPase catalytic and immuno-activities in rat exorbital lacrimal gland

The subcellular distribution of Na,K-ATPase in rat lacrimal gland acinar cells was surveyed by subcellar fractionation followed by determination of two Na,K-ATPase catalytic activities, K(+)-dependent p-nitrophenylphosphate hydrolysis and ouabain-sensitive ATP hydrolysis, by Western blotting of isolated membrane fractions, and by analysis of lacrimal tissue with immunocytochemical methods at the light and EM levels. Both catalytic activities distributed in parallel after centrifugation on sorbitol gradients. They were associated with membrane samples that appeared to be derived from: (1) acinar cell basal-lateral membranes; (2) the Golgi complex; and (3) endocytic compartments. beta 1-subunit immunoreactivity closely paralleled catalytic activity. The alpha 1-subunit immunoreactivity distribution suggested the presence of alpha 1-subunits in alpha beta complexes and excess alpha 1 subunits which were not assembled with beta subunits and not catalytically active. In the putative basal-lateral membrane and endocytic samples, alpha 1-reactivity was associated primarily with a 100-kDa band, while in the Golgi samples it was associated primarily with 40 and 60-kDa bands. beta 1-reactivity was also heterogeneous, with reactivity in basal-lateral membrane and putative endocytic samples associated with a broad band of 50-54 kDa, and reactivity in Golgi samples associated with discrete bands of 50, 52, and 54 kDa. Staining with anti-holoenzyme and anti-alpha 1-subunit antibodies yielded strong indirect immunofluorescence signals both in plasma membrane and in intracellular regions of acinar cells. beta 1-like immunoreactivity was concentrated in cytoplasmic regions of acinar cells. Immunogold electron microscopy revealed positive staining with anti-holoenzyme in Golgi membranes of acinar cells and in basal-lateral membranes of duct cells. These data support the hypothesis that lacrimal acinar cells contain substantial cytoplasmic pools of Na,K-ATPase and that there is a location-dependent heterogeneity which is not detected by immunocytochemical methods.

Plasma membrane internalization and recycling in rabbit lacrimal acinar cells

PURPOSE

The purpose of this study was to examine internalization and recycling of plasma membrane constituents in lacrimal gland acinar cells.

METHODS

Acinar cells were isolated from rabbit lacrimal glands. Surface-expressed reactive groups were biotinylated at 4 degrees C with sulfo-N-hydroxysuccinimidyl-biotin. Incorporated biotin was then labeled with avidin-horseradish peroxidase complex for light microscopy, with avidin-lucifer yellow conjugate for fluorescence microscopy, and quantitative fluorometry, and with avidin-ferritin conjugate for electron microscopy.

RESULTS

At 4 degrees C labels remained at the surfaces of intact cells. Surface avidin-lucifer yellow decreased markedly, giving way to punctate cytoplasmic labeling, on warming to 37 degrees C. Electron microscopy of cells warmed after labeling with avidin-ferritin revealed ferritin in smooth vesicles underlying the plasma membranes, in vesicles adjacent to Golgi membranes, and in multivesicular bodies. Incubation at 37 degrees C before chilling and labeling with avidin-lucifer yellow decreased the cells' capacity to bind avidin-lucifer yellow by 95%, with t0.5 < 0.5 min. If cells were then incubated with avidin-lucifer yellow at 37 degrees C, they took up the marker with a time course that indicated that 60% of the initial biotin either recycled back to the plasma membrane or remained in intracellular compartments that could be reached by endocytosed extracellular fluid. Internalized biotin communicated with extracellular avidin-lucifer yellow with a t0.5 of 2 min, and this process was accelerated by carbachol at concentrations of 10 mumol/l and 1 mmol/l.

CONCLUSIONS

Acinar cell plasma membrane constituents participate in an ongoing, secretagogue-modulated recycling traffic between small surface-expressed pools and 10- to 20-fold larger intracellular pools.

Uveoscleral permeability to intracamerally infused ferritin in eyes of rabbits and monkeys

The permeability of the uveoscleral outflow pathway from the anterior ocular chamber was examined in rabbit and monkey eyes using anionic ferritin as a tracer. Ferritin, infused intracamerally, had ready access to the choroidal interstitium, and the degree of penetration was generally correlated with the time and pressure relationships during infusion. In both species, there were accumulations of tracer in intercellular spaces at the lamina fusca, but tracer was also present in the sclera. Thus, in contrast to the situation in the eyes of hamsters, the uveoscleral outflow pathway in the eyes of rabbits and monkeys includes the choroidal connective tissue and allows passage of relatively large molecular weight substances.

Evaluating sensory regulation as a method to improve awareness in patients with altered states of consciousness: a pilot study

The status of sensory stimulation as a clinical procedure is still in some doubt. Recent papers have shown no significant clinical changes as a result of sensory intervention but this may be due to an inappropriate model on which these procedures were based. This paper outlines the results of a controlled pilot study, based on a sensory regulation model currently being tested at the Casa Colina Peninsula Rehabilitation Center, Los Angeles. The study contrasts the outcome of four patients treated in a sensory regulated environment with four who were exposed to sensory stimulation of an unregulated kind. The results are quite encouraging in favour of a sensory regulation approach.

The effect of exposure to a delta cya/delta crp mutant of Salmonella typhimurium on the subsequent colonization of swine by the wild-type parent strain

This study characterizes the clinical response and colonization pattern of caesarean-derived, colostrum-deprived swine exposed to a delta cya/delta crp mutant (chi 4233) of S. typhimurium and challenged with the wild-type parent strain. chi 4233 was mildly virulent in swine and induced transient fever and soft stools. Chi 4233 colonized the ileum, cecum, liver, spleen, tonsils, and mandibular and ileocolic lymph nodes of swine in a manner similar to the parental wild-type, but the numbers of S. typhimurium (chi 4233) in the ileum were 100- to 1000-fold less than those of pigs exposed to the parental wild-type. Pigs exposed to chi 4233 21 days before parental wild-type challenge demonstrated a milder clinical response to challenge than did pigs that did not receive chi 4233. The wild-type populations in the ilea of chi 4233-exposed pigs after challenge were 100- to 10,000-fold less than those in pigs not receiving chi 4233. The liver, spleen, and ileocolic lymph nodes were cleared of wild-type S. typhimurium more quickly after challenge in chi 4233-exposed pigs. The populations of chi 4233 in the ilea of exposed pigs after wild-type challenge were also less than would have been expected in unchallenged pigs. Thus, exposure of swine to a delta cya/delta crp mutant of S. typhimurium modulated the subsequent response to parental wild-type challenge and reduced carrier populations of wild-type S. typhimurium in infected swine.

Alteration of neutrophil function in BCG-treated and non-treated swine after exposure to Salmonella typhimurium

Salmonella typhimurium infection in swine causes an enterocolitis followed by a persistent carrier state, but little is known about the mechanisms that allow this organism to colonize and persist in host tissues. Neutrophils provide a first line of defense against invading pathogens such as Salmonella typhimurium. The purpose of this study was to evaluate porcine neutrophil function after in vivo exposure to Salmonella and to determine if the immunomodulator, bacillus Calmette Guerin (BCG), exerts any effect on neutrophil function or on the colonization and persistence of S. typhimurium in the pig. Compared to negative controls, neutrophils from pigs exposed to S. typhimurium exhibited significantly decreased iodination, cytochrome-C reduction, antibody-dependent cell-mediated cytotoxicity, random migration, and chemotaxis (P less than or equal to 0.05). Neutrophil bactericidal activity against S. typhimurium was significantly enhanced. Most of the significant differences were noted in the first two days after exposure to Salmonella. Often the functional alterations were biphasic, peaking again 7-10 days after exposure. BCG alone significantly depressed random migration and cytochrome-C reduction in unstimulated neutrophils. The clinical course, colonization pattern, and persistence of Salmonella were similar between pigs receiving BCG and untreated pigs. These data suggest that S. typhimurium infection causes a depression in oxidative metabolism and motility, yet an increase in overall bactericidal activity against S. typhimurium in circulating porcine neutrophils. It also appears that BCG treatment, as reported here, does not enhance resistance of pigs to S. typhimurium colonization or reduce the number of persistent organisms in the porcine ileum.

Populations of Salmonella typhimurium in internal organs of experimentally infected carrier swine

Experiments were conducted to determine comparative populations of Salmonella typhimurium in the most commonly infected body organs of long-term carrier swine. Naturally farrowed Salmonella-free pigs (n = 58) were orally exposed to S typhimurium when they were 47 days old. Necropsy of 3 to 5 randomly selected pigs was conducted at 3, 7, 10, 14, and 17 days and at 3, 4, 5, 6, 8, 12, 16, 20, 24, and 28 weeks after exposure. Mean populations (log10/g) of S typhimurium in palatine tonsils, ileum, cecum (wall and contents), ascending colon (wall and contents), and mandibular and ileocolic lymph nodes were estimated at each necropsy, using a most-probable-number method of bacteriologic examination. Populations of organisms in cecum and colon were similar to each other throughout the duration of the study. Mean populations (log10/g) associated with cecal and colonic walls decreased from 6.1 and 6.6, respectively, during the first postexposure (PE) week to less than or equal to 1.67 from PE weeks 4 to 28. Populations (log10/g) associated with cecal and colonic contents decreased from 5.6 and 5.5, respectively, at PE day 3 to 2.5 and 2.7, respectively, at PE week 4, and remained less than or equal to 2.8 until week 28. Populations (log10/g) associated with intestinal walls and contents were closely correlated during the study. Population (log10/g) in the ileum was greater than or equal to 5.3 from PE days 3 to 17, then varied between 5.4 and -0.4 up to PE week 28.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolactin localization, binding, and effects on peroxidase release in rat exorbital lacrimal gland

Prolactin immunoreactivity has been detected in human tears and in lacrimal glands, and it has been suggested that this hormone might be a modulator of lacrimal secretion as well as a component of lacrimal gland fluid. The present study was designed to confirm the immunocytochemical localization of prolactin in the rat lacrimal gland, to determine the source of the prolactin, and to evaluate the acute effects of prolactin on lacrimal secretory function. We have confirmed that prolactin-like immunoreactivity is present in secretory vesicles of acinar cells of male and female Sprague-Dawley rats. Prolactin message was present at detectable levels in RNA extracts of lacrimal glands from males, indicating that at least a component of the prolactin-like immunoreactivity was the product of synthesis within the lacrimal glands. Crude membrane fractions from acini isolated from males bound 43.1 +/- 3.2 femtomoles prolactin/mg protein (mean +/- standard error of the mean; n = 6), which was significantly (P less than 0.01) more than comparable fractions from females (15.4 +/- 2.4 fmoles/mg protein, n = 6). Preincubating membranes at 65 degrees for 20 min to release endogenous ligands increased prolactin binding to 84.8 +/- 20.8 fmoles/mg protein for males and 63.8 +/- 17.4 fmoles/mg protein for females (P greater than 0.1), suggesting that, on average, similar numbers of receptors are expressed in acinar cells of male and female rats but a larger fraction of the receptors is occupied by endogenous prolactin-like peptides in females. Because prolactin binding triggers prolactin receptor internalization in various cell types, we propose that the prolactin-like immunoreactivity in lacrimal acinar cells of females has been accumulated from the circulation, while the immunoreactivity seen in males results, at least in part, from de novo synthesis. Ovine prolactin at concentrations of 10-20 ng/ml inhibited carbachol-induced peroxidase release by 19.6% +/- 6.9% (n = 8, P less than 0.02) but failed to alter peroxidase release in the absence of carbachol. These observations suggest that prolactin might function as an endocrine, paracrine, or autocrine modulator in the lacrimal gland.

Laser reflections from surgical instruments

The potential hazards to the eye and skin from accidental exposures caused by reflected laser beams from surgical instruments has long been of concern to operating room staff members. Reflectance values for argon neodymium:YAG and CO2 laser wave-lengths were measured from 29 reference surfaces used on surgical instruments. From these measurements, nominal hazard zones could be determined for typical reflection hazards.

Critical analysis of the concept of sensory stimulation for patients in vegetative states

The practice of coma arousal and sensory stimulation is becoming the focus of heated debate. There is no theory on which patients may benefit, at what time in their recovery, or how the 'arousal' or 'stimulation' procedures should be applied. This paper considers some of the information processing mechanisms that are important mediators of arousal and awareness, pointing to some of the weaknesses in current practices and suggesting alternative approaches. Recommendations for a conceptual model of sensory stimulation are given that might provide a more scientific perspective to those who use such methods.

Experimental establishment of persistent infection in swine with a zoonotic strain of Salmonella newport

An experiment was conducted to determine whether a persistent Salmonella newport infection could be established in swine, to determine duration of shedding and distribution of the organism in internal organs, and to determine whether changes occurred in antimicrobial susceptibility or plasmid profile of the organism during the course of long-term infection. Naturally farrowed Salmonella-free pigs (n = 22) were orally exposed to a multiply antimicrobial-resistant zoonotic strain of S newport when they were 7 weeks old. Tonsillar and rectal swab specimens were examined bacteriologically for S newport during the first week after exposure, then weekly for 7 weeks. Fecal samples were likewise examined weekly or every 2 weeks for 28 weeks after exposure. Necropsies of 2 or 3 randomly selected pigs were conducted at 2, 4, 8, 12, 16, 20, 24, and 28 weeks after exposure. A total of 45 specimens/pig representing the following internal organs or tissues were examined bacteriologically for S newport: liver, spleen, kidney, gallbladder, heart, heart blood, lung, stomach, and tonsils; segments of the intestinal tract with corresponding lymph nodes; and lymph nodes from lymphocenters of the head and neck, thoracic cavity, thoracic limbs, abdominal viscera, and abdominal wall. Exposure to S newport induced a mild and transient clinical response. The organism was recovered from 97% of tonsillar swab specimens and 89% of rectal swab specimens collected during 7 weeks after exposure and from 98% of fecal samples collected during 28 weeks after exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Analytic subcellular fractionation of acini from rat lacrimal gland

A recent hypothesis for the cellular mechanism of fluid secretion by lacrimal acini has been based, in part, on the results of subcellular fractionation analyses of lacrimal gland fragments which had been incubated for a brief period in vitro. An important assumption in those studies was that the ion transporters and neurotransmitter receptors measured in isolated subcellular fractions were associated with membranes derived from the acinar cells, since these comprise the bulk of the lacrimal gland mass. This study was undertaken to validate this assumption. Acinar complexes were isolated from rat exorbital lacrimal glands by digestion with collagenase, hyaluronidase, and DNase. Although terminal intralobular duct segments and myoepithelial cells were occasionally noted, the preparations appeared to be free of larger ducts, blood cells, blood vessels, and interstitial cells. Acinar cells were then disrupted, and the homogenates underwent the fractionation procedure used previously for lacrimal gland fragment preparations. This procedure involved a sequence of analyses by differential sedimentation, isopycnic centrifugation on sorbitol gradients, and partitioning in dextran-polyethyleneglycol two-phase systems. Calculated initial specific activities for sodium/potassium adenosinetriphosphatase (Na+/K(+)-ATPase), alkaline phosphatase, acid phosphatase, and succinate dehydrogenase were identical to those obtained from fragment preparations. Major membrane populations resolved by the sequential analyses, including one believed to represent endoplasmic reticulum membranes, two believed to be derived from the acinar cell basal-lateral membrane, and two believed to be derived from the Golgi complex, corresponded closely to populations resolved from lacrimal fragment preparations. In addition to validating the previous use of lacrimal gland fragment preparations in studies of acinar cell function, these results suggest that preparations of isolated lacrimal acini will be useful for future work on neurotransmitter-receptor regulation and basal-lateral plasma membrane dynamics in the lacrimal gland.

Structural analysis of potential barriers to bulk-flow exchanges between uvea and sclera in eyes of Macaque monkeys

The uveal tract of the eyes of monkeys was examined by electron microscopy using both thin sections and freeze-fracture replicas. The ultrastructural features of the lamina fusca in the monkey resembled those previously described for rabbit. The lamina fusca was composed of numerous interleaved processes of fibroblastic and pigmented cells and contained tight junctions between fibroblastic cell processes that were predominantly discontinuous, as well as numerous fenestrations through the attenuated cell processes. There was no regional compaction of cellular processes traversing the entire uvea at the level of the ora serrata as reported previously in hamster eyes.