Mechanisms of leukocyte trafficking into the CNS

HIV-1 encephalitis occurs in up to one-third of HIV-1-infected individuals. The mechanisms through which this pathology develops are thought to involve viral passage across the blood-brain barrier (BBB), as well as entry of HIV-infected and/or uninfected inflammatory cells into the central nervous system (CNS). Viral proteins and cytokines may also contribute to the pathogenesis of encephalitis. We show that the chemokines SDF-1 and MCP-1 induce transmigration of uninfected human lymphocytes and monocytes across our model of the BBB, a co-culture of human fetal astrocytes and endothelial cells. We also demonstrate that the HIV-1 protein Tat induces adhesion molecule expression and chemokine production by human fetal astrocytes and microglia, which could further contribute to leukocyte entry into the CNS. Finally, our data indicate that inflammatory cytokines modulate the expression of CXCR4, a co-receptor for HIV-1, on human fetal astrocytes, suggesting that these cytokines may potentially modulate the infectability of astrocytes by HIV-1. These findings support the hypothesis that there may be several different mechanisms that contribute to the development and progression of HIV-1 encephalitis.

Colocalization of basic fibroblast growth factor and CD44 isoforms containing the variably spliced exon v3 (CD44v3) in normal skin and in epidermal skin cancers

Previous in vitro studies have shown CD44 isoforms containing the alternatively spliced exon v3 (CD44v3) to be modified with heparan sulphate (HS) and to bind HS-binding basic fibroblast growth factor (bFGF). Here, we demonstrate that exogenously added bFGF is also bound in vivo by CD44v3-positive keratinocytes in normal skin and by tumour cells in basal cell carcinoma and squamous cell carcinoma (SCC), two skin cancers of keratinocyte origin. bFGF binding and CD44v3 expression were colocalized in cultured human normal keratinocytes (HNK) and on the SCC cell line A431. By contrast, benign or malignant tumours of melanocyte origin failed to express CD44v3 and bound no bFGF. The bFGF binding to normal or transformed keratinocytes in vivo and in vitro was dependent on HS modification, as it was completely eliminated by pretreatment with heparitinase or by blocking with free heparin, whereas chondroitinase had no effect. In addition, specific removal of CD44v3 by antibody-induced shedding also diminished bFGF binding to keratinocytes. Furthermore, bFGF stimulated the proliferation of CD44v3-positive HNK and A431 in a dose-dependent fashion. This bFGF effect was again completely abolished by heparitinase or free heparin, but not by chondroitinase. In aggregate, our results suggest that a function of HS-modified CD44 isoforms such as CD44v3 in skin is to present the HS-binding growth factor bFGF, thereby stimulating the proliferation of normal or transformed keratinocytes.

Analysis of mouse dendritic cell migration in vivo upon subcutaneous and intravenous injection

Dendritic cells (DC) have an increasingly important role in vaccination therapy; therefore, this study sought to determine the migratory capacity and immunogenic function of murine bone-marrow (BM)-derived DC following subcutaneous (s.c.) and intravenous (i.v.) injection in vivo. DC were enriched from BM cultures using metrizamide. Following centrifugation, the low-buoyant density cells, referred to throughout as DC, were CD11c(high), Iab(high), B7-1(high) and B7-2(high) and potently activated alloreactive T cells in mixed lymphocyte reactions (MLR). In contrast, the high-density cells expressed low levels of the above markers, comprised mostly of granulocytes based on GR1 expression, and were poor stimulators in MLR. Following s.c. injection of fluorescently labelled cells into syngeneic recipient mice, DC but not granulocytes migrated to the T-dependent areas of draining lymph nodes (LN). DC numbers in LN were quantified by flow-cytometric analysis, on 1, 2, 3, 5 and 7 days following DC transfer. Peak numbers of around 90 DC per draining LN were found at 2 days. There was very little migration of DC to non-draining LN, thymus or spleen at any of the time-points studied. In contrast, following i.v. injection, DC accumulated mainly in the spleen, liver and lungs of recipient mice but were largely absent from peripheral LN and thymus. The ability of DC to induce T-cell-mediated immune responses was examined using trinitrobenzenesulphate (TNBS)-derivatized DC (TNBS-DC) to sensitize for contact hypersensitivity responses (CHS) in naive syngeneic recipients. Following s.c. injection, as few as 105 TNBS-DC, but not TNBS-granulocytes, sensitized for CHS responses. However, the same number of TNBS-DC failed to induce CHS following i.v. injection. In summary, this study provides new and quantitative data on the organ specific migration of murine BM-derived DC following s.c. and i.v. injection. The demonstration that the route of DC administration determines the potency of CHS induction, strongly suggests that the route of immunization should be considered in the design of vaccine protocols using DC.

Rats selectively bred for high and low swim-test activity show differential responses to dopaminergic drugs

RATIONALE

Selective breeding of Sprague-Dawley rats has been used to generate a line of animals with very low swim-test activity (SwLo) in an attempt to model certain characteristics of depression. For comparison with the SwLo animals, a line bred for high swim-test activity (SwHi) and a non-selectively bred line (SwNS) have been generated. Previous studies using these lines suggested an inverse relationship between dopamine (DA) function in the brain and inactivity in the swim test.

OBJECTIVES

The current experiments investigated the possibility that SwLo and SwHi rats show differences in central DA processes, as suggested by responsiveness to DA agonists.

RESULTS

The increase in ambulation produced by d-amphetamine (0.25-1.0 mg/kg) was largest in SwHi rats and smallest in SwLo rats, with SwNS rats showing an intermediate response. Amphetamine levels in plasma and brain tissue were similar in SwHi and SwLo rats, indicating that pharmacokinetic differences were not responsible for the behavioral differences. Repeated amphetamine administration produced enhancement in the ambulation-increasing effects of this drug (i.e., sensitization), with significant enhancement seen in all three lines. Apomorphine in doses that stimulate postsynaptic receptors (0.25-4.0 mg/kg) produced mainly increased sniffing behaviors in SwHi and SwNS rats and oral behaviors in SwLo rats, suggesting that the lines differ in proportions of D1, D2, and D3 postsynaptic receptors.

CONCLUSIONS

The findings suggest that DA function differs in lines of rats selectively bred for differences in swim behavior, a feature that may make these lines useful for studying certain depressive symptoms that might be related to DA function.

HIV-1 Tat Induces Monocyte Chemoattractant Protein-1-Mediated Monocyte Transmigration Across a Model of the Human Blood-Brain Barrier and Up-Regulates CCR5 Expression on Human Monocytes

AIDS dementia is characterized by neuronal loss in association with synaptic damage. A central predictor for clinical onset of these symptoms is the infiltration of monocytes and macrophages into CNS parenchyma. Chronic HIV-1 infection of monocytes also allows these cells to serve as reservoirs for persistent viral infection. Using a coculture of endothelial cells and astrocytes that models several aspects of the human blood-brain barrier, we examined the mechanism whereby the HIV-derived factor Tat may facilitate monocyte transmigration. We demonstrate that treatment of cocultures on the astrocyte side with HIV-1 Tat induced significant monocyte chemoattractant protein (MCP)-1 protein. Astrocytes, but not endothelial cells, were the source of this MCP-1 expression. Supernatants from Tat-treated cocultures induced significant monocyte transmigration, which was detected by 2.5 h after the addition of PBMC. Pretreatment of the supernatants from Tat-stimulated cocultures with an Ab to MCP-1 completely blocked monocyte transmigration. Flow cytometric analysis of Tat-stimulated PBMC demonstrated that Tat up-regulated expression of the chemokine receptor, CCR5, on monocytes in a time-dependent manner. Taken together, our data indicate that HIV-1 Tat may facilitate the recruitment of monocytes into the CNS by inducing MCP-1 expression in astrocytes. These recruited monocytes may contribute to the pathogenesis of HIV-1-associated AIDS encephalitis and dementia.

HIV-1 Tat induces monocyte chemoattractant protein-1-mediated monocyte transmigration across a model of the human blood-brain barrier and up-regulates CCR5 expression on human monocytes

AIDS dementia is characterized by neuronal loss in association with synaptic damage. A central predictor for clinical onset of these symptoms is the infiltration of monocytes and macrophages into CNS parenchyma. Chronic HIV-1 infection of monocytes also allows these cells to serve as reservoirs for persistent viral infection. Using a coculture of endothelial cells and astrocytes that models several aspects of the human blood-brain barrier, we examined the mechanism whereby the HIV-derived factor Tat may facilitate monocyte transmigration. We demonstrate that treatment of cocultures on the astrocyte side with HIV-1 Tat induced significant monocyte chemoattractant protein (MCP)-1 protein. Astrocytes, but not endothelial cells, were the source of this MCP-1 expression. Supernatants from Tat-treated cocultures induced significant monocyte transmigration, which was detected by 2.5 h after the addition of PBMC. Pretreatment of the supernatants from Tat-stimulated cocultures with an Ab to MCP-1 completely blocked monocyte transmigration. Flow cytometric analysis of Tat-stimulated PBMC demonstrated that Tat up-regulated expression of the chemokine receptor, CCR5, on monocytes in a time-dependent manner. Taken together, our data indicate that HIV-1 Tat may facilitate the recruitment of monocytes into the CNS by inducing MCP-1 expression in astrocytes. These recruited monocytes may contribute to the pathogenesis of HIV-1-associated AIDS encephalitis and dementia.

Evidence for involvement of B lymphocytes in the surveillance of lung metastasis in the rat

These studies examined the composition of lymphocytes within the lung after the introduction of tumor cells that metastasize to the lung in rats. i.v. delivery of MADB106 tumor cells into syngeneic Fischer 344 rats caused dose- and time-dependent development of lung tumors, with surface metastases evident 7 days after injection and markedly increased 11 days after injection. The total number of lymphocytes recovered from the lung was increased 11 days after injection but not 7 days after injection. When lymphocytes from the lung, spleen, and blood were subjected to fluorescence-activated cell sorting analysis, the most conspicuous change was an increase in the percentage of CD45RA+ cells (i.e., B lymphocytes in the rat) in the lung, with no changes seen in the percentage of natural killer (NKR-P1+), CD4+, or CD8+ cells in the lung. Analysis of the time course showed that B lymphocytes increased in the lung soon after i.v. tumor injection, with an initial peak seen 6 h after injection. Rapid influx of B lymphocytes into lung after i.v. tumor cell injection was also observed in another syngeneic tumor model, i.e., after injection of CC531 cells into WAG rats. To determine whether the influx of B lymphocytes into the lung might participate in tumor surveillance, a high dose of antibody (100 microg) to rat B lymphocytes was given to immunoneutralize these cells; this produced an increase in lung tumors in both models. Finally, Fischer 344 rats were given a s.c. injection of MADB106 tumor cells that made them resistant to lung tumors when given a later i.v. injection of these tumor cells. These animals were found to have an elevated level of B lymphocytes residing in the lung associated with the resistance to lung tumor. These findings suggest that early responses of B lymphocytes are important in protection against tumor development in two rat models of cancer.

In vivo UVA-1 and UVB irradiation differentially perturbs the antigen-presenting function of human epidermal Langerhans cells

Ultraviolet B (UVB, 290-320 nm) radiation is known to suppress the immune function of epidermal Langerhans cells. We have recently described that in vitro UVB irradiation perturbs the antigen-presenting cell function of Langerhans cells by inhibiting their expression of functional B7 costimulatory molecules (B7-1, B7-2). The aim of this study was to determine wavelength-specific UV effects on Langerhans cells function in vivo, specifically UVB and UVA-1. To address this issue, volunteers were irradiated on the sun protected volar aspects of their forearms with 3 x minimal erythema dose of UVB (Philips TL-12) and UVA-1 (UVASUN 5000 Mutzhaas). Langerhans cells were isolated from suction blister roofs immediately following irradiation. Langerhans cells isolated from UVB- but not from UVA-1-irradiated skin failed to activate naïve resting allogeneic T cells (mixed epidermal cell leukocyte reaction) or primed tetanus toxoid reactive autologous T cells. Langerhans cells isolated from sham-irradiated or UVA-1-irradiated skin strongly upregulated B7-2 molecules during short-term tissue culture. By contrast, Langerhans cells from UVB-irradiated skin did not upregulate B7-2 molecules. Furthermore, exogenous stimulation of the B7 pathway by anti-CD28 stimulatory monoclonal antibodies restored the capacity of UVB-irradiated Langerhans cells to activate both alloreactive and tetanus toxoid-reactive T cells, implying suppressed antigen-presenting cell activities and perturbed B7 expression of Langerhans cells isolated from UVB-irradiated skin are related. Those studies demonstrate that in vivo UVB, but not UVA-1, interferes with the activation-dependent upregulation of B7 molecules on Langerhans cells, which in turn is of functional relevance for the perturbed antigen-presenting cell function of Langerhans cells within UVB- but not UVA-1-irradiated skin.

Motor activation by amphetamine infusion into nucleus accumbens core and shell subregions of rats differentially sensitive to dopaminergic drugs

Selective breeding based on activity in a swim test has been used to produce lines of rats that show a high level of activity in the swim test (Swim High-active (SwHi) rats) and a low level of activity in the swim test (Swim Low-active (SwLo) rats). Previous studies have indicated that dopamine (DA) function is enhanced in SwHi rats and reduced in SwLo rats; a principal finding was that SwLo rats showed much smaller increases in ambulatory activity after systemic administration of amphetamine than did SwHi or non-selected rats. In light of the importance of the nucleus accumbens (NAC) in amphetamine-induced activity, the present study investigated whether DA function in NAC differs in SwHi and SwLo rats. Amphetamine was infused bilaterally into either the core or shell subregion of NAC, and ambulation or swim test activity was then measured. In SwLo rats, infusion of amphetamine (0.2-2.0 microg) into either NAC core or shell produced moderate increases in ambulation. In SwHi rats, infusion of amphetamine into NAC shell produced similar moderate increases in ambulation, but infusion into the core produced markedly larger dose-related increases in ambulation. In the swim test, infusion of amphetamine (1.0 microg) increased activity by affecting the dominant behavior of each line; i.e. struggling increased in SwHi rats and floating decreased in SwLo rats, with large effects seen in both lines with infusion into either NAC core or shell. These results support the idea that the distinct behavioral characteristics of SwHi and SwLo rats are mediated in part by differences in NAC-DA function.

Galanin: a significant role in depression?

This paper describes a hypothesis that attempts to account for how changes in noradrenergic systems in the brain can affect depression-related behaviors and symptoms. It is hypothesized that increased activity of the locus coeruleus (LC) neurons, the principal norepinephrine (NE)-containing cells in the brain, causes release of galanin (GAL) in the ventral tegmentum (VTA) from LC axon terminals in which GAL is colocalized with NE. It is proposed that GAL release in VTA inhibits the activity of dopaminergic cell bodies in this region whose axons project to forebrain, thereby resulting in two of the principal symptoms seen in depression, decreased motor activation and decreased appreciation of pleasurable stimuli (anhedonia). The genesis of this hypothesis, which derives from studies using an animal model of depression, is described as well as recent data consistent with the hypothesis. The formulation proposed suggests that GAL antagonists may be of therapeutic benefit in the treatment of depression.

Astrocyte-derived monocyte-chemoattractant protein-1 directs the transmigration of leukocytes across a model of the human blood-brain barrier

The migration of leukocytes across the blood-brain barrier (BBB) into the central nervous system is critical in the pathogenesis of central nervous system inflammatory diseases. The production of chemokines, such as monocyte-chemoattractant protein-1 (MCP-1), by endothelial cells (EC) and astrocytes may initiate and amplify this process. Using a coculture of human EC and astrocytes to model the BBB, we demonstrated that exogenous MCP-1 induces the transmigration of monocytes in a dose-dependent manner. TNF-alpha, IFN-gamma, or IL-1beta treatment of cocultures also induced significant migration of monocytes that correlates with the induction of MCP-1 protein. TGF-beta, previously shown to induce MCP-1 expression in astrocytes, but not in EC, caused migration of monocytes across cocultures, but not across EC grown alone. Monocytes and lymphocytes transmigrated across cytokine-treated cocultures in greater numbers than across EC alone. Astrocytes were the main source of cytokine-induced MCP-1, supporting a role for astrocytes in facilitating leukocyte transmigration. A blocking Ab to MCP-1 inhibited MCP-1- and cytokine-induced transmigration of monocytes by 85-90%. Cytokine treatment of cocultures also resulted in the transmigration of activated, CD69-positive lymphocytes. The MCP-1-mediated transmigration of monocytes across cocultures was blocked using an Ab to ICAM-1 and inhibited by 55% using an Ab to E-selectin. These data suggest a central role for astrocyte-derived MCP-1 in directing the migration of monocytes and lymphocytes across the BBB.

Astrocyte-Derived Monocyte-Chemoattractant Protein-1 Directs the Transmigration of Leukocytes Across a Model of the Human Blood-Brain Barrier

The migration of leukocytes across the blood-brain barrier (BBB) into the central nervous system is critical in the pathogenesis of central nervous system inflammatory diseases. The production of chemokines, such as monocyte-chemoattractant protein-1 (MCP-1), by endothelial cells (EC) and astrocytes may initiate and amplify this process. Using a coculture of human EC and astrocytes to model the BBB, we demonstrated that exogenous MCP-1 induces the transmigration of monocytes in a dose-dependent manner. TNF-α, IFN-γ, or IL-1β treatment of cocultures also induced significant migration of monocytes that correlates with the induction of MCP-1 protein. TGF-β, previously shown to induce MCP-1 expression in astrocytes, but not in EC, caused migration of monocytes across cocultures, but not across EC grown alone. Monocytes and lymphocytes transmigrated across cytokine-treated cocultures in greater numbers than across EC alone. Astrocytes were the main source of cytokine-induced MCP-1, supporting a role for astrocytes in facilitating leukocyte transmigration. A blocking Ab to MCP-1 inhibited MCP-1- and cytokine-induced transmigration of monocytes by 85–90%. Cytokine treatment of cocultures also resulted in the transmigration of activated, CD69-positive lymphocytes. The MCP-1-mediated transmigration of monocytes across cocultures was blocked using an Ab to ICAM-1 and inhibited by 55% using an Ab to E-selectin. These data suggest a central role for astrocyte-derived MCP-1 in directing the migration of monocytes and lymphocytes across the BBB.

The low molecular weight Dextran 40 inhibits the adhesion of T lymphocytes to endothelial cells

Dextrans are complex colloidal macromolecules widely used as haemorrheologic substances and anti-thrombotic agents. Here we describe a novel function of Dextran 40 by demonstrating an inhibition of T lymphocyte adhesion to endothelial cells (EC). We applied an established microassay in which constitutive and tumour necrosis factor-alpha (TNF-alpha)-induced binding of mouse T lymphoma cells (TK-1) to mouse endothelioma (eEND.2) cells is mediated by the interaction of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on EC with their counter-receptors the LFA-1 heterodimer (CD11a/CD18) and VLA-4 on T cells. Dextran 40 in therapeutically achievable levels (2-32 mg/ml) reduced both constitutive and TNF-alpha-stimulated TK-1 adhesion to eEND.2. Selective preincubation of eEND.2 or TK-1 revealed that Dextran 40 acted exclusively on the T cells. To explore further the mechanisms by which Dextran 40 interfered with TK-1 adhesion, their LFA-1 and VLA-4 expression was analysed by FACS. The surface expression levels of neither receptor were affected by Dextran 40. However, confocal microscopy revealed that Dextran 40 interfered with the activation-dependent capping and clustering of LFA-1 and VLA-4 on the surface of TK-1. We conclude that Dextran 40 inhibits the capacity of TK-1 T cells to adhere to eEND.2 endothelial cells and thus may be useful for therapeutic intervention in diseases associated with enhanced T lymphocyte binding to microvascular endothelium.

Genetic analysis of 53 lymph node-negative breast carcinomas by CGH and relation to clinical, pathological, morphometric, and DNA cytometric prognostic factors

Within the subgroup of lymph node-negative breast cancers, there is a need for accurate prognostic indicators to select high-risk patients. Comparative genomic hybridization (CGH) provides an opportunity to screen the whole genome for chromosomal aberrations which may be associated with poor clinical outcome. The results of CGH analysis of 53 lymph node-negative breast carcinomas are presented and correlated with a set of clinico-pathological and cytometric features with strong prognostic value. The most frequent chromosomal gains were, in descending order of frequency, 8q, 1q, Xq, 5q, 4q, and 3q. Recurring losses were observed at chromosomal arms 19p, 1p, 17p, 22q, 4q, and 8p. There was not a single, unique combination of chromosomal aberrations, but gains of 1q and 8q were frequently observed simultaneously (15/53 cases). DNA aneuploid tumours harboured more gains than DNA diploid tumours, but there was no correlation between the total number of events per tumour detected by CGH and any of the prognostic features. Of the many chromosomal aberrations found, only gains of chromosome 8q were strongly correlated with high values of mean nuclear area. A clearer picture was obtained when comparing only those cases which, according to their cytometric and morphometric features, had either the worst or the best prognosis. Gains occurred mainly in the 'poor prognostic features' group, in particular at 8q, 11q13, 17q, and 20q. It is hypothesized that these gains could be late, progression-related events and may be associated with aggressive clinical behaviour. These four chromosomal regions may therefore be of potential prognostic value. Correlation with real follow-up data will enable us better to identify those patients who have a high risk of recurrence within the subgroup of lymph node-negative breast cancer patients.

CD44 variant isoforms are essential for the function of epidermal Langerhans cells and dendritic cells

Upon antigen encounter epidermal Langerhans cells (LC) and dendritic cells (DC) emigrate from peripheral organs and invade lymph nodes through the afferent lymphatic vessels and then assemble in the paracortical T cell zone and present antigen to T lymphocytes. Part of this process is mimicked by metastasizing tumor cells. Since splice variants of CD44 promote metastasis to lymph nodes we explored the expression of CD44 proteins on migrating LC and DC. We show that following antigen contact, LC and DC upregulate pan CD44 epitopes and epitopes encoded by variant exons v4, v5, v6 and v9. Antibodies against CD44 epitopes arrest LC in the epidermis, prevent the binding of activated LC and DC to the T cell zones of lymph nodes, and severely inhibit their capacity to induce a delayed type hypersensitivity reaction to a skin hapten in vivo. Our results demonstrate that CD44 splice variant expression is obligatory for the migration and function of LC and DC.

Astrocyte expression of monocyte chemoattractant protein-1 is differentially regulated by transforming growth factor beta

The pathophysiology of central nervous system (CNS) inflammatory disease is dependent, in part, on leukocyte recruitment across the blood-brain barrier. The expression of cytokines and chemokines by astrocytes may contribute to this process. Astrocytes express monocyte chemoattractant protein-1 (MCP-1), an activator of monocytes and a chemoattractant for monocytes and activated T cells. We examined the regulation of MCP-1 expression in human fetal astrocytes following cytokine treatment in the presence and absence of transforming growth factor beta (TGF-beta). TGF-beta, TNFalpha and IL-1beta, but not IFNgamma, induced MCP-1 mRNA and protein. TGF-beta, in cotreatment with TNFalpha caused an additive increase in MCP-1 mRNA, but not protein. In combination with IFNgamma, TGF-beta significantly increased MCP-1 mRNA and protein, as compared to either untreated, TGF-beta- or IFNgamma-treated astrocytes. However, TGF-gamma in cotreatment with IL-1beta decreased MCP-1 mRNA and protein, as compared to IL-1beta alone. Treatment of astrocytes with TGF-beta prior to TNFalpha, IFNgamma or IL-1beta treatment significantly increased MCP-1 expression. The kinetics of cytokine expression in the CNS may differentially regulate astrocyte-derived MCP-1 expression and subsequent recruitment and activation of leukocytes.

Effect of modular head seating on the cement-stem interface strength of femoral prostheses

This study tested the hypothesis that modular head seating in situ reduces the cement-stem interfacial strength. Femoral prostheses were implanted in eight pairs of cadaveric femurs; one femur of each pair received a stem for which the modular head was seated by dropping a weight from a given height (treated); the contralateral femur received a nonseated stem (control). Transverse sections were cut from four standardized locations on each implanted femur, and the yield shear stress and ultimate shear stress of the interface were determined from push-out tests. There was no significant difference in cement-stem interfacial strength between seated and nonseated prostheses. These results suggest that seating modular heads in situ has no deleterious effect on the acute interfacial strength of cemented femoral implants.

Treatment of leg edema and wounds in a patient with severe musculoskeletal injuries

This case report describes the application of a technique for the treatment of leg edema and wounds resulting from a severe distal tibiofibular fracture. Following injury and numerous fracture- and wound-related surgeries in the first year postinjury, this patient developed leg edema, required daily treatment of 2 leg wounds, and was unable to wear a shoe due to foot swelling. He was referred to the physical therapy clinic 1 year postinjury for ankle rehabilitation and to diminish the leg edema. Therapy consisting of manual lymph drainage, compressive bandaging, exercise, and skin care was provided for 7 weeks. A compression stocking was issued near the end of treatment, which the patient continued to wear daily thereafter. At the time of discharge from therapy, the leg edema had decreased 74% and the wound area of both wounds had decreased 89%. Improvements continued following discharge. By 10 weeks after the start of treatment, edema had decreased 80.9%, one wound had healed, and the second wound was 93% improved. The patient was able to wear a shoe and resume recreational activities. This case report provides insight into a treatment that may shorten rehabilitation and control the cost of caring for injuries complicated by prolonged edema.

Selective breeding of rats for high and low motor activity in a swim test: toward a new animal model of depression

Because low motor activity ina swim test has been found to represent "depression-like" behavior in the rat, Sprague-Dawley (SD) albino rats were selectively bred for low motor activity (low struggling time/high floating time) in a swim test, while others were bred for high motor activity (high struggling time/low floating time). Eighty-four male and 42 female SD rats were initially purchased from Charles-River Breeding Laboratories in 1987, their behavior assessed in a 15-min swim test, and selective breeding carried out by mating those male and female rats that showed either low or high levels of motor activity in the test; results from behavioral testing of the first 18 generations produced by this selective breeding process are reported here. Two rat lines have been obtained, Swim Low-Active (SwLo) and Swim High-Active (SwHi) rats, which differ dramatically in swim-test behavior--SwLo rats show little struggling and much floating, while SwHi rats show the reverse. Activity scores of individual SwLo and SwHi rats now show no overlap. Selective breeding has produced bidirectional changes; that is, SwLo rats are considerably less active than randomly bred Sprague-Dawley albino rats, while SwHi rats are considerably more active than randomly bred rats. Measuring activity of SwLo and SwHi rats in other situations--ambulation in the home cage, open-field activity, exploratory activity in a novel, home cage-like situation, and immobility in the Porsolt swim test--revealed that differences are most pronounced when animals respond to acute challenges; under these conditions, SwHi rats show active, assertive behavior, whereas SwLo rats show a distinct absence of this type of response. When SwLo rats from the 8th to the 11th generations were given antidepressant medication [desipramine, (DMI), a tricyclic, or phenelzine, an MAO inhibitor], chronic but not acute administration of both drugs increased swim-test activity of SwLo rats. Buspirone, an anxiolytic, did not increase activity of SwLo rats. Use of animals selectively bred for high and low activity in the swim test may represent a new tool for studying physiological processes relevant to affective disorders and for testing antidepressant drugs/treatments.

Dual action of androgen on calcium signaling and luteinizing hormone secretion in pituitary gonadotrophs

An increase in serum androgen levels associated with a suppression of cyclic gonadotropin secretion is frequently observed in females with impaired ovarian function. Here, we addressed the hypotheses that androgens (testosterone and dihydrotestosterone) alter gonadotropin secretion by modulating agonist-induced Ca2+ signaling and/or Ca(2+)-controlled exocytosis. In mixed populations of pituitary cells from female rats, addition of testosterone reduced basal and agonist (GnRH)-induced gonadotropin secretion in a concentration- and time-dependent manner. The suppressive actions of this androgen on gonadotropin secretion were observed over the full GnRH concentration range. Reduction in agonist-induced gonadotropin secretion was also observed after addition of dihydrotestosterone, indicating that the inhibitory action of testosterone is not mediated by its conversion to estradiol. Both the extracellular Ca(2+)-independent spike phase and extracellular Ca(2+)-dependent sustained phase of GnRH-induced gonadotropin secretions were affected by testosterone. In part, the inhibitory action of testosterone was mediated by attenuation of GnRH-induced InsP3 production and InsP3-dependent Ca2+ mobilization. In addition, testosterone exhibited a Ca(2+)-independent action on gonadotropin secretion, as documented by attenuation of high potassium-induced secretion without an affect on depolarization-induced Ca2+ signals. These results suggest that androgen inhibition of gonadotropin secretion occurs at two distinct steps in the secretory pathway, one prior to and one after elevation in cytosolic Ca2+ concentration.

Effects of antidepressant drugs on rats bred for low activity in the swim test

To determine responsivity to antidepressant medication of Sprague-Dawley rats bred for low activity in the swim test [Swim Low-Active (SwLo) rats], these animals were given different antidepressant drugs via subcutaneously implanted minipumps for 1, 12, or 26 days, and then were tested for activity in the swim test and 2 days later in the open field. Antidepressant drugs given were amitriptyline, imipramine, desipramine (tricyclics), phenelzine (monoamine oxidase inhibitor (MAOI)], fluoxetine [selective serotonin reuptake inhibitor (SSRI)], venlafaxine, and bupropion (atypical). To assess specificity of response, the nonantidepressant drugs amphetamine, caffeine, and haloperidol were also tested. For comparison, several drugs were also tested in rats bred for high activity in the swim test [Swim High-Active (SwHi) rats]. When administered for 14 and/or 28 days (but not for 1 day), imipramine, desipramine, venlafaxine, phenelzine, and bupropion significantly increased struggling behavior of SwLo rats in swim test. No nonantidepressant drug significantly elevated struggling activity. Long-term administration of phenelzine and bupropion also significantly decreased floating behavior in the swim test, although amphetamine also had this effect at all times of administration. No significant effects of antidepressants were seen in SwHi rats. Amitriptyline and fluoxetine were ineffective in altering either struggling or floating in SwLo rats; however, a high dose of an SSRI (sertraline) did reduce floating, but this type of effect is probably not indicative of antidepressant action. Behavior in the open field was not consistently affected by any drug type. It is concluded that, based on pharmacological response profile in the swim test, SwLo rats represent depression that is responsive to potent norepinephrine reuptake-blocking antidepressants and also MAOIs; atypical depression may fit this profile.

Activation-dependent modulation of hyaluronate-receptor expression and of hyaluronate-avidity by human monocytes

During inflammation, activated monocytes (Mo) migrate into tissues where they interact with extracellular matrix components such as hyaluronate (HA), produced in high amounts at inflammatory sites. We determined whether Mo that had invaded sites of cutaneous inflammation bind HA and express the putative HA receptors CD44 isoforms, ICAM-1, or receptor for hyaluronate-mediated motility (RHAMM). In cutaneous inflammation, activated infiltrating Mo displayed high HA avidity and expressed epitopes encoded by CD44s, CD44 variant exons v3, v4, v5, v6, v7, and v9, and ICAM-1, but not RHAMM. We further investigated how activation affects the avidity of Mo for HA and which receptors were responsible for such binding. Mo freshly purified from human peripheral blood bound little HA and expressed CD44s but no epitopes encoded by CD44v exons, ICAM-1, or RHAMM. During short-term tissue culture, Mo upregulated their HA avidity and expression of ICAM-1, CD44s, and epitopes encoded by CD44v, all of which were further augmented by IFN-gamma or lipopolysaccharide, whereas RHAMM was not detectable. Thus in vitro activated Mo resembled Mo that had migrated to inflammatory sites in vivo. Lipolysaccharide or IFN-gamma-induced HA binding was inhibited by more than 90% with monoclonal antibodies directed against N-terminal HA binding domains of CD44s, but not by monoclonal antibodies against CD44v epitopes or ICAM-1. In conclusion, we show that upon in vitro or in vivo activation, Mo enhance their capacity to bind HA. This is critically dependent upon the expression ofCD44s epitopes. Regulated CD44-HA interactions may be important for the ability of Mo to migrate into and within sites of inflammation and for Mo effector functions.

Further characterization of UVB radiation effects on Langerhans cells: altered expression of the costimulatory molecules B7-1 and B7-2

We have reported previously that low-dose UVB radiation (UVBR, 50-200 J/m2) perturbs the antigen-presenting cell (APC) function of murine Langerhans cells (LC) by interfering with yet undefined costimulatory signals. In this study, we investigated (1) the effects of UVBR on the expression of the costimulatory molecules B7-1 and B7-2 on murine LC, (2) the functional consequences of defective B7-1 and B7-2 signalling on primary and secondary T-cell responses induced by LC and (3) the mechanism by which UVBR interferes with B7-1 and B7-2 expression. Ultraviolet-B radiation dose-dependently inhibited the culture-induced upregulation of B7-1 and B7-2 on LC from both UVB-susceptible (UVBs, C57BL/6) and UVB-resistant (UVBR, Balb/c) mice and abrogated their capacity to stimulate proliferation of naive alloreactive T cells and of the KLH (keyhole limpet hemocyanin)-specific T helper (Th)1 clone HDK-1. The UVBR-induced suppression of B7-1 and B7-2 on LC and their perturbed APC function were related, because exogenous triggering of the B7/CD28 pathway with a stimulatory monoclonal antibody (mAb) for CD28 to UVB-irradiated LC partially restored T-cell proliferation. Such reconstitution was not observed when the mAb was added to killed LC, indicating that the UVBR-induced suppression of APC function was not due to lethal effects on LC. Conditioned supernatants from UVB-irradiated epidermal cells did not inhibit the functional upregulation of B7-1 and B7-2, suggesting that UVBR inhibits B7-1 and B7-2 upregulation by acting directly on LC and not by altering LC costimulatory function via release of soluble immunosuppressive factors. In conclusion, UVBR distorts the functional expression of B7-1 and B7-2 on LC from both UVBS and UVBR mice, thereby contributing to the failure of UVB-irradiated LC to stimulate resting alloreactive T cells or KLH-specific Th1 cells.