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C A Haas

Publications and source records attributed to C A Haas.

At least 19 recordsLinked to original sources
PubMed2001

Targeting gene-modified hematopoietic cells to the central nervous system: use of green fluorescent protein uncovers microglial engraftment.

Gene therapy in the central nervous system (CNS) is hindered by the presence of the blood-brain barrier, which restricts access of serum constituents and peripheral cells to the brain parenchyma. Expression of exogenously administered genes in the CNS has been achieved in vivo using highly invasive routes, or ex vivo relying on the direct implantation of genetically modified cells into the brain. Here we provide evidence for a novel, noninvasive approach for targeting potential therapeutic factors to the CNS. Genetically-modified hematopoietic cells enter the CNS and differentiate into microglia after bone-marrow transplantation. Up to a quarter of the regional microglial population is donor-derived by four months after transplantation. Microglial engraftment is enhanced by neuropathology, and gene-modified myeloid cells are specifically attracted to the sites of neuronal damage. Thus, microglia may serve as vehicles for gene delivery to the nervous system.

Animals↗
PubMed2001

Sprouting in the hippocampus after entorhinal cortex lesion is layer- specific but not translaminar: which molecules may be involved?

Entorhinal cortex lesion partially denervates the rat fascia dentata. This is said to induce sprouting of intact fibers from neighboring layers that invade the zone of the degenerating axons. However, recent in vivo and in vitro studies failed to demonstrate sprouting across laminar boundaries. Sprouting does occur, but it mainly involves unlesioned fiber systems terminating within the layer of fiber degeneration. These findings point to laminar cues that promote sprouting of fibers within the denervated zone while repelling other, adjacent fiber systems that try to grow into the denervated zone. A group of molecules that are likely to guide the sprouting process and the formation of borders are extracellular matrix molecules synthesized by reactive astrocytes. These molecules provide boundaries for growing axons during development. Some extracellular matrix molecules (tenascin-C, DSD- 1 -proteoglycan, neurocan, and brevican) were upregulated within the denervated outer molecular layer after lesion of the entorhinal cortex, suggesting a similar role after lesion. These extracellular matrix components forin a sharp molecular border towards the adjacent nondenervated inner molecular layer, and their pattern of distribution correlates precisely with the laminar termination pattern of the sprouting fiber populations. Thus, extracellular matrix molecules could delineate boundaries of axonal growth after entorhinal cortex lesion and could thus contribute to the molecular processes underlying the postlesional re-patterning of the fascia dentata.

Animals↗
PubMed2000

Entorhinal cortex lesion does not alter reelin messenger RNA expression in the dentate gyrus of young and adult rats.

The extracellular matrix protein reelin plays an important role in neuronal pattern formation and axonal collateralization during the development of the central nervous system. With the concept that reelin might also be important for axonal growth in the injured nervous system we investigated whether reelin is re-expressed in areas of collateral sprouting after brain injury. The expression of reelin messenger RNA was studied in the denervated fascia dentata of adult rats one, four, seven and 14 days following entorhinal cortex lesion. In adult control animals, in situ hybridization histochemistry with digoxigenin-labeled reelin riboprobes revealed reelin messenger RNA expression in neurons located in the outer molecular layer and beneath the granule cell layer of the dentate gyrus. After entorhinal cortex lesion, this expression pattern did not change during the whole post-lesional time period investigated despite a strong glial activation and reactive sprouting in the outer molecular layer of the dentate gyrus as visualized by immunohistochemistry for glial fibrillary acidic protein and acetylcholinesterase histochemistry, respectively. The expression of reelin messenger RNA was also unaffected by entorhinal cortex lesion in the dentate gyrus of young animals (postnatal day seven), where an even stronger sprouting response occurs.

Age Factors↗
PubMed2000

Up-regulation of growth-associated protein 43 mRNA in rat medial septum neurons axotomized by fimbria-fornix transection.

Transection of septohippocampal fibres is widely used to study the response of CNS neurons to axotomy. Septohippocampal projection neurons survive axotomy and selectively up-regulate the transcription factor c-Jun. In the present study we investigated whether these cells concomitantly up-regulate the growth-associated protein-43 (GAP-43), a potential target gene of c-Jun implicated in axonal growth and regeneration. Using in situ hybridization histochemistry (ISHH) it was demonstrated that postlesional c-jun mRNA expression is accompanied by an increased expression of GAP-43 mRNA in the medial septum 3 days following fimbria-fornix transection (FFT). The increase reached a maximum at 7 days and gradually declined thereafter (17 days, 3 weeks). Retrograde prelabeling with Fluoro-Gold followed by axotomy and ISHH revealed that GAP-43 mRNA was up-regulated in septohippocampal projection neurons. Colocalization of GAP-43 mRNA and choline acetyltransferase protein showed that GAP-43 mRNA was expressed by cholinergic medial septal neurons after axotomy. Selective immunolesioning of the cholinergic component of the septohippocampal projection with 192 IgG-saporin followed by FFT demonstrated that GAP-43 mRNA was also synthesized by axotomized GABAergic neurons. These results demonstrate an up-regulation of GAP-43 mRNA in axotomized septohippocampal projection neurons independent of their transmitter phenotype which is closely correlated with c-Jun expression. Because the GAP-43 gene contains an AP-1 site, we hypothesize a c-Jun-driven up-regulation of GAP-43 in lesioned medial septal neurons that may contribute to their survival and regenerative potential following axotomy.

Animals↗
PubMed2000

The chondroitin sulphate proteoglycan brevican is upregulated by astrocytes after entorhinal cortex lesions in adult rats.

The chondroitin sulphate proteoglycan brevican is one of the most abundant extracellular matrix molecules in the adult rat brain. It is primarily synthesized by astrocytes and is believed to influence astroglial motility during development and under certain pathological conditions. In order to study a potential role of brevican in the glial reaction after brain injury, its expression was analysed following entorhinal cortex lesion in rats (12 h, 1, 2, 4, 10, 14 and 28 days and 6 months post lesion). In situ hybridization and immunohistochemistry were employed to study brevican mRNA and protein, respectively, in the denervated outer molecular layer of the fascia dentata and at the lesion site. In both regions brevican mRNA was upregulated between 1 and 4 days post lesion. The combination of in situ hybridization with immunohistochemistry for glial fibrillary acidic protein demonstrated that many brevican mRNA-expressing cells are astrocytes. In the denervated zone of the fascia dentata, immunostaining for brevican was increased by 4 days, reached a maximum by 4 weeks and remained detectable up to 6 months post lesion. Electron microscopic immunocytochemistry showed that brevican is a component of the extracellular matrix compartment. At the lesion site a similar time course of brevican upregulation was observed. These data demonstrate that brevican is upregulated in areas of brain damage as well as in areas denervated by a lesion. They suggest a role of brevican in reactive gliosis and are compatible with the hypothesis that brevican is involved in the synaptic reorganization of denervated brain areas.

Acetylcholinesterase↗
PubMed2000

Reorganization of the rat fascia dentata after a unilateral entorhinal cortex lesion. Role of the extracellular matrix.

Entorhinal cortex lesion (ECL) partially denervates the fascia dentata of the hippocampus. This is said to induce the sprouting of intact fibers from neighboring layers that invade the zone of the degenerating axons. However, recent studies using anterograde tracing failed to demonstrate sprouting across laminar boundaries. Sprouting does occur, but it mainly involves unlesioned fiber systems terminating within the layer of fiber degeneration. It is now of interest to identify the cues that could underlie this layer-specific sprouting response. Since extracellular matrix (ECM) molecules delineate boundaries of axonal growth during development, it was tested whether these molecules play a similar role during the sprouting process following ECL. After ECL, reactive astrocytes rapidly synthesize and secrete growth-inhibiting ECM molecules, such as tenascin-C and the chondroitin sulfate proteoglycan neurocan, into the ECM of the outer molecular layer. These molecules form a sharp border against the nondenervated inner molecular layer. This pattern of ECM molecule expression may contribute to the layer-specific sprouting response of surviving afferents after ECL: axons trying to grow into the denervated outer molecular layer, for example, from the inner molecular layer, would be deflected by a growth-inhibiting ECM barrier.

Animals↗
PubMed1999

Entorhinal cortex lesion in adult rats induces the expression of the neuronal chondroitin sulfate proteoglycan neurocan in reactive astrocytes.

The chondroitin sulfate proteoglycan neurocan is a major component of brain extracellular matrix during development. Neurocan is primarily synthesized by neurons and has the ability to interact with cell adhesion molecules involved in the regulation of cell migration and axonal growth. Within the first weeks postnatally, neurocan expression is strongly downregulated. To test whether neurocan is reexpressed in areas of axonal growth (sprouting) after brain injury, the time course of neurocan expression was analyzed in the denervated fascia dentata of the rat after entorhinal cortex lesion (12 hr; 1, 2, 4, and 10 d; 2 and 4 weeks; and 6 months after lesion). In the denervated zone, immunohistochemistry revealed neurocan-positive astrocytes by 2 d after lesion and a diffuse labeling of the extracellular matrix at all later time points. Electron microscopy confirmed the deposition of neurocan in the extracellular matrix compartment. In situ hybridization demonstrated a strong upregulation of neurocan mRNA within the denervated outer molecular layer 1 and 4 d after lesion. The combination of in situ hybridization with immunohistochemistry for glial fibrillary acidic protein demonstrated that the neurocan mRNA-expressing cells are astrocytes. These data demonstrate that neurocan is reexpressed in the injured brain. In contrast to the situation during development, astrocytes, but not neurons, express neurocan and enrich the extracellular matrix with this molecule. Similar to the situation during development, neurocan is expressed in an area of active axon growth, and it is suggested that neurocan acts to maintain the boundaries of the denervated fascia dentata after entorhinal cortex lesion.

Animals↗
PubMed1999

Expression of CNTF/LIF-receptor components and activation of STAT3 signaling in axotomized facial motoneurons: evidence for a sequential postlesional function of the cytokines.

Several lines of evidence suggest that ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF) are important for the survival and regeneration of axotomized motoneurons. To investigate the role of CNTF/LIF signaling in regenerative responses of motoneurons, we studied the expression of the three receptor components, CNTF receptor alpha (CNTFRalpha), LIF receptor beta (LIFRbeta), and gp130, and the activation of the STAT3 signal transduction pathway in the rat facial nucleus following peripheral nerve transection. As shown by in situ hybridization and immunoblotting, axotomy resulted in a rapid down-regulation of CNTFRalpha mRNA expression within 24 h and a concomitant massive up-regulation of LIFRbeta mRNA and protein in the lesioned motoneurons. The altered mRNA levels were maintained for 3 weeks but had returned back to control levels by 6 weeks postlesion after successful regeneration. In contrast, mRNA levels remained in the lesioned state during the 6-week period studied, when regeneration was prevented by nerve resection. Significant lesion-induced changes in gp130 mRNA levels were not detectable. Rapid (within 24 h) and sustained (for at least 5 days) activation of STAT3 in axotomized facial motoneurons was revealed by demonstrating the phosphorylation and nuclear translocation of the protein using immunocytochemistry and immunoblotting. In agreement with previous studies showing a complementary regulation of CNTF and LIF in the lesioned facial nerve, our observations on the postlesional regulation of CNTF/LIF receptor components in the facial nucleus indicate a direct and sequential action of the two neurotrophic proteins on axotomized facial motoneurons.

Acute-Phase Proteins↗
PubMed1999

Penile fracture and testicular rupture.

Traumatic injuries to the penis and testicles are uncommon, likely due to the well-protected location and degree of mobility of these organs. Because of this the management of these injuries has historically been controversial. However, current literature supports immediate evaluation and surgical repair of these traumatic injuries to prevent complications such as erectile dysfunction or testicular loss. Herein the diagnostic and therapeutic options for both traumatic penile fracture and testicular rupture are reviewed with emphasis on immediate evaluation and repair.

Humans↗
PubMed1999

Intraurethral alprostadil for treatment of erectile dysfunction in patients with spinal cord injury.

OBJECTIVES: To assess the efficacy of intraurethral prostaglandin E1 (alprostadil, MUSE) in treating erectile dysfunction in patients with spinal cord injury (SCI). METHODS: Intraurethral alprostadil was tested in 15 patients with SCI to evaluate its effectiveness in treating SCI-associated erectile dysfunction. All patients were at least 1 year after injury, and all had previously used intracavernosal injections successfully (Schramek's grade 5 erection). The intraurethral drug was administered in the office, in the presence of a physician, with monitoring of blood pressure. If effective, the patient was then able to use MUSE at home. The first 3 patients underwent gradual dose escalation starting with 125 microg, without the use of a constriction ring. Because of hypotension, the remaining 12 patients all used a penile constriction ring prior to intraurethral drug administration using 1000 microg. The quality of the erection was compared with that achieved with intracavernosal injections using Schramek's grading. RESULTS: The dose escalation (titration) in the first 3 patients demonstrated that the 1000-microg dose was the most effective in creating an erectile response. Transient hypotension was noted in these first 3 patients in whom the constricting band was not used. The highest dose of MUSE (1000 microg) was, therefore, used in the remaining 12 patients, with the constriction band. The quality of the erection varied and appeared to be less rigid in all patients (12 patients with grade 1 to 3; 3 patients with grade 4) than that noted with intracavernosal injection therapy (1 5 patients with grade 5). There was no incidence of priapism. The 3 patients with grade 4 erections tried the MUSE at home. All 3 patients were dissatisfied with the quality of the erection and did not continue to use the MUSE at home and returned to intracavernosal injection therapy. CONCLUSIONS: MUSE appears to be somewhat effective in creating erections; however, these were less rigid erections than those obtained with intracavernosal therapy and provided less overall satisfaction. It should always be used in the patient with SCI after placement of a constriction ring to prevent hypotension. Its ultimate use depends on the patient's level of satisfaction with the quality of the erection compared with intracavernosal injections.

Adult↗
PubMed1999

Differential induction of c-Fos, c-Jun and Jun B in the rat central nervous system following unilateral entorhinal cortex lesion.

In order to identify some of the molecular mechanisms that occur after a central nervous system trauma, the immediate early gene encoded proteins c-Fos, c-Jun and Jun B were analysed by immunocytochemistry following unilateral entorhinal cortex lesion (controls, 30 min, 2, 5, 12 and 24 h, two, six, 10 and 14 days, four weeks and six months postlesion). In the dentate gyrus, c-Fos was induced in some supragranular neurons (30 min), massively expressed in granule cells ipsilaterally to the lesion (2 h), expressed in hilar neurons (5 h and two days) and was absent at all later stages. A basal expression of c-Jun was found in dentate granule cells of controls, which was strongly increased on the lesion side (2 h) and on the side contralateral to the lesion (12 h). c-Jun expression returned to control levels by 24 h. Jun B was induced in granule cells ipsilateral to the lesion within 2 h and was back to control levels by 5 h. In the lateral septal area, c-Fos and c-Jun were induced 30 min postlesion and decreased rapidly thereafter. In the cerebral cortex, a widespread induction of c-Fos and c-Jun occurred within 30 min after entorhinal cortex lesion and this up-regulation lasted until two days postlesion. These data indicate that electrolytic lesion of the entorhinal cortex leads to a rapid and widespread induction of c-Fos, c-Jun and Jun B. Within the denervated fascia dentata, some of these changes may be linked to the reorganization processes following the lesion. Alternatively, the alterations in immediate early gene expression reported here may be due to changes in synaptic activity or postlesional seizures which occur in this lesioning paradigm.

Animals↗
PubMed1999

Limitations of routine spiral computerized tomography in the evaluation of bladder trauma.

PURPOSE: We evaluate the accuracy of spiral computerized tomography (CT) in diagnosing traumatic bladder rupture. MATERIALS AND METHODS: Medical records of 24 consecutive patients diagnosed with traumatic bladder rupture at our level 1 trauma center from 1993 to 1998 were retrospectively reviewed. Of the patients 15 underwent retrograde cystography and spiral CT of the abdomen and pelvis. The results of these imaging studies were compared. RESULTS: Retrograde cystography successfully diagnosed all cases of bladder rupture and correctly classified injuries confirmed surgically. Spiral CT successfully diagnosed 9 of 15 bladder ruptures (60%), and correctly classified 4 of 5 intraperitoneal (80%) and 6 of 11 extraperitoneal (55%) ruptures. CONCLUSIONS: Spiral CT is less accurate than retrograde cystography in diagnosing traumatic bladder rupture.

Adolescent↗
PubMed1998

Region-specific activation of microglial cells in the rat septal complex following fimbria-fornix transection.

Studies of postlesional microglial activation may gain insight into microglia/neuronal interactions in processes of neurodegeneration. We compared the microglial response after axotomy of septohippocampal projection neurons with that seen after selective immunolesioning of cholinergic septohippocampal neurons with the immunotoxin 192 IgG-saporin. Using the microglial marker isolectin B4 from Griffonia simplicifolia (GSA I-B4), we found striking differences in the microglial response between these two lesion paradigms. Following axotomy of septohippocampal neurons by fimbria-fornix transection (ff-t), there was only a moderate and short-lasting microglial reaction in the medial septum (MS) in the early postlesion period. Prelabeling of septohippocampal neurons with Fluoro-Gold (FG) prior to axotomy revealed the survival of most neurons, and only very rarely were microglial cells observed that had phagocytosed FG-labeled debris. In the lateral septum (LS) containing the degenerating terminals of hippocamposeptal fibers transected by ff-t, a heavy reaction of lectin-labeled activated microglial cells associated with high phagocytotic activity was noticed. Unexpectedly, after a long survival time (6 months) following ff-t, we observed an increase in microglial GSA I-B4 labeling in the MS. In contrast, an inverse pattern of the microglial response, i.e., a strong initial reaction in the MS and very little microglial activation in the LS, was observed after immunolesioning. Our results indicate that the microglial reaction in the MS following ff-t differs substantially from that seen in other models of axotomy.

Animals↗
PubMed1998

Cultured astrocytes express functional receptors for galanin.

The neuropeptides galanin and calcitonin gene-related peptide (CGRP) are strongly up-regulated in motoneurons following axotomy. Earlier reports have suggested that peptides might be released from injured neurons to recruit surrounding glia. In this study, the effects of galanin and CGRP on cultured rat astrocytes were investigated using the expression of immediate early genes as a model for receptor-mediated transcriptional activation. Galanin was found to induce c-fos, junB, and Tis11 mRNA in cultured astrocytes, providing evidence for the presence of functional galanin receptors on neuroglial cells. In contrast, CGRP only led to the induction of c-fos and junB mRNA. Cholecystokinin (CCK-8) and substance P, which are also up-regulated in select motoneuron populations following axotomy, fail to induce immediate early genes in astrocytes, indicating specificity of neuropeptides in their ability to stimulate glial cells. The differential induction of immediate early gene expression by galanin and CGRP in astrocytes points to differences in intracellular signal transduction mechanisms. Whereas CGRP was found to stimulate the accumulation of cyclic AMP by 10- to 20-fold, galanin had no effect on basal cyclic AMP content. The effect of CGRP on cyclic AMP accumulation was completely reversed by the CGRP receptor antagonist, CGRP(8-37). These results suggest roles for galanin and CGRP in the transcriptional activation of astrocytes.

Animals↗
PubMed1998

Inguinal scrotal incision for penile fracture.

PURPOSE: We report a new incision for repair of penile fracture. MATERIALS AND METHODS: We describe 2 cases in which the inguinal scrotal incision was used for repair of penile fracture. The preoperative evaluation as well as the technical case and rationale for use of this incision are discussed. RESULTS: Preoperative cavernosogram delineated the site of the fracture. Immediate repair of the fracture using the inguinal scrotal incision was successful. CONCLUSIONS: The inguinal scrotal incision should be entertained for cases of penile fracture. It avoids incision into markedly edematous penile skin and allows for excellent visualization of the fracture site.

Adult↗
PubMed1998

Erectile dysfunction in aging: upregulation of endothelial nitric oxide synthase.

OBJECTIVES: To evaluate whether alterations in nitric oxide (NO) synthesis or activity contribute to age-related erectile dysfunction and to elucidate the mechanisms causing these alterations using the rabbit as our model of aging. METHODS: We compared the ability of the rabbit cavernosal smooth muscle to relax in the organ bath in response to acetylcholine (Ach, endothelium-dependent vasodilator), sodium nitroprusside (SNP, an NO donor), and A23187 (a calcium ionophore) in young (6 month old) and aged (2.5 to 3.5 year old) rabbits. In addition, the immunohistochemical expression of endothelial nitric oxide synthase (eNOS) in both young and aged rabbit cavernosal tissue was examined. Endothelial integrity was examined immunohistochemically with JC70. RESULTS: Ach-mediated relaxation of penile corporal tissue was significantly attenuated from a maximum of 68.39 +/- 6.27 (0.1 mM Ach, n = 4) in young rabbits to 39.02 +/- 4.88 (0.1 mM Ach, n = 6) in aged rabbits (P < 0.04). No statistically significant difference (P > 0.05) was noted between cavernosal relaxation to sodium nitroprusside between young rabbits (97.8%, 0.1 mM SNP, n = 5) and aged rabbits (76.1%, 0.1 mM SNP, n = 5). This suggested that the defect in the Ach-NO pathway was at the level of NO synthesis, not activity. Immunohistochemical staining for eNOS demonstrated upregulation in both the vascular endothelium and corporal smooth muscle of aged rabbit tissue compared with young rabbit cavernosal tissue (n = 5). Anatomic endothelial integrity was demonstrated in the young and aged rabbits by the presence of JC70. This suggested that the defect in the Ach-NO synthetic pathway was not at the level of eNOS and was not due to anatomic endothelial cell disruption. Finally, Ach-mediated cavernosal smooth muscle relaxation in the young rabbit was not significantly augmented (P > 0.05) in the presence of the calcium ionophore A23187 (10 microM). A23187, however, significantly augmented (P < 0.04) Ach-mediated relaxation in the aged rabbit from a maximum of 33.93 +/- 6.58 to 41.55 +/- 6.58 (10 microM Ach, n = 5). This suggested that a potential defect in the Ach-NO synthetic pathway was at the level of intracellular calcium flux and possibly at the level of the calcium-eNOS interaction. CONCLUSIONS: Endothelium-dependent relaxation is attenuated in the aging rabbit; eNOS is upregulated in the aging rabbit; and no difference is noted in response to direct NO donation between the young and aged rabbit. The endothelium is anatomically intact in both the young and aging rabbit. The calcium ionophore A23187 augmented the attenuated vasorelaxation in the aging rabbit cavernosum (although not to the levels seen in the young rabbit cavernosum) and had no effect on the young rabbit cavernosum. These data suggest that erectile dysfunction in the aging rabbit cavernosum appears to be related to endothelial dysfunction and is characterized by eNOS upregulation and aberrant intracellular calcium fluxes.

Acetylcholine↗