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Traumatic brain injury (TBI), often called the signature wound of Iraq and Afghanistan wars, is characterized by a progressive histopathology and long-lasting behavioral deficits. Treatment options for TBI are limited and patients are usually relegated to rehabilitation therapy and a handful of experimental treatments. Stem cell-based therapies offer alternative treatment regimens for TBI, and have been intended to target the delayed therapeutic window post-TBI, in order to promote “neuroregeneration,” in lieu of “neuroprotection” which can be accomplished during acute TBI phase. However, these interventions may require adjunctive pharmacological treatments especially when aging is considered as a comorbidity factor for post-TBI health outcomes. Here, we put forward the concept that a combination therapy of human umbilical cord blood cell (hUCB) and granulocyte-colony stimulating factor (G-CSF) attenuates neuroinflammation in TBI, in view of the safety and efficacy profiles of hUCB and G-CSF, their respective mechanisms of action, and efficacy of hUCB+G-CSF combination therapy in TBI animal models. Further investigations on the neuroinflammatory pathway as a key pathological hallmark in acute and chronic TBI and also as a major therapeutic target of hUCB+G-CSF are warranted in order to optimize the translation of this combination therapy in the clinic.

In conclusion, proof of the principle exists that neural grafts can survive transplantation in PD and that this graft survival is related to preliminary evidence of clinical benefit and improvement on FD-PET. Two prospective, randomized, surgical placebo-controlled trials of fetal tissue transplantation for the treatment of PD will be published in the near future, as will results of a placebo-controlled xenograft trial. Lifelong survival of human fetal nigral grafts is likely. The striatum is comparatively simple to target surgically in comparison to other sites such as the subthalamic nucleus. Several new sources of dopamine cells are being developed for transplantation purposes. Long-term monitoring for toxicity, such as the development of dyskinesias, will be needed, and dose-escalation trials should be performed slowly due to the irreversible nature of transplants. There are numerous ways to improve current techniques of neural transplantation.

Because mecamylamine, a nicotinic receptor antagonist, is used so often in nicotine research and because mecamylamine may have important therapeutic properties clinically, it is important to fully explore and understand its pharmacology. In the present study, the efficacy and potency of mecamylamine and its stereoisomers were evaluated as inhibitors of human alpha 3 beta 4, alpha 3 beta 2, alpha 7, and alpha 4 beta 2 nicotinic acetylcholine receptors (nAChRs), as well as mouse adult type muscle nAChRs and rat N-methyl-D-aspartate (NMDA) receptors expressed in Xenopus oocytes. The selectivity of mecamylamine for neuronal nAChR was manifested primarily in terms of slow recovery rates from mecamylamine-induced inhibition. Neuronal receptors showed a prolonged inhibition after exposure to low micromolar concentrations of mecamylamine. Muscle-type receptors showed a transient inhibition by similar concentrations of mecamylamine, and NMDA receptors were only transiently inhibited by higher micromolar concentrations. Mecamylamine inhibition of neuronal nAChR was noncompetitive and voltage dependent. Although there was little difference between S-(+)-mecamylamine and R-(-)-mecamylamine in terms of 50% inhibition concentration values for a given receptor subtype, there appeared to be significant differences in the off-rates for the mecamylamine isomers from the receptors. Specifically, S-(+)-mecamylamine appeared to dissociate more slowly from alpha 4 beta 2 and alpha 3 beta 4 receptors than did R-(-)-mecamylamine. In addition, it was found that muscle-type receptors appeared to be somewhat more sensitive to R-(-)-mecamylamine than to S-(+)-mecamylamine. Together, these findings suggest that in chronic (i.e., therapeutic) application, S-(+)-mecamylamine might be preferable to R-(-)-mecamylamine in terms of equilibrium inactivation of neuronal receptors with decreased side effects associated with muscle-type receptors.

Cell transplantation into host brain requires a reliable cell marker to trace lineage and location of grafted cells in host tissue. The lacZ gene encodes the bacterial (E. coli) enzyme beta-galactosidase (beta-gal) and is commonly visualized as a blue intracellular precipitate following its incubation with a substrate, "X gal," in an oxidation reaction. LacZ is the "reporter gene" most commonly employed to follow gene expression in neural tissue or to track the fate of transplanted exogenous cells. If the reaction is not performed carefully-with adequate optimization and individualization of various parameters (e.g.. pH, concentration of reagents, addition of chelators, composition of fixatives) and the establishment of various controls--then misleading nonspecific background X-gal positivity can result, leading to the misidentification of cells. Some of this background results from endogenous nonbacterial beta-gal activity in discrete populations of neurons in the mammalian brain; some results from an excessive oxidation reaction. Surprisingly, few articles have empha sized how to recognize and to eliminate these potential confounding artifacts in order to maximize the utility and credibility of this histochemical technique as a cell marker. We briefly review the phenomenon in general, discuss a specific case that illustrates how an insufficiently scrutinized X-gal positivity can be a pitfall in cell transplantation studies, and then provide recommendations for optimizing the specificity and reliability of this histochemical reaction for discerning E. coli beta-gal activity.

Huntington's disease is a fatal neurological disorder characterized by chorea and deterioration in cognitive and neuropsychiatric function. Primary pathological changes are found in the striatum, where GABAergic neurons undergo degenerative changes. Local interneurons are relatively spared. Here, we describe the rationale for clinical trials of fetal striatal tissue transplantation for the treatment of Huntington's disease. Specifically, the reasons for utilizing tissue derived from the far lateral aspect of the lateral ventricular eminence as a source of striatal tissue will be discussed.

We have previously demonstrated that fetal nigral grafts can survive, reinnervate the striatum, and mediate clinically relevant recovery in a patient with Parkinson's disease (PD). Most previous autopsy cases have failed to identify meaningful numbers of viable grafted cells suggesting that differences in critical transplant variables determine graft viability. The present study evaluated the structural and functional correlates of fetal nigral transplantation in a second PD patient who received fetal nigral grafts according to our previously published transplant protocol. A 61-year-old woman with severe PD received bilateral fetal nigral grafts to the postcommissural putamen from seven donor fetuses (four right side and three left side) aged 6.5-9 weeks postconception. This patient died 19 months after surgery from a cause unrelated to the transplant surgery. Her postoperative clinical course was characterized by improved motor and activities of daily living scores during "off time," reduced "off time," and increased "on" time without dyskinesia. Positron emission tomography (PET) scans revealed a bilateral and progressive increase in fluorodopa (FD) uptake within the grafted putamen. Postmortem examination of the right hemisphere revealed large oval-shaped grafts containing more than 138,000 tyrosine-hydroxylase-immunoreactive (TH-ir) neurons. Grafted cells formed a seamless border with the host and provided dense TH-ir innervation to 78% of the host postcommissural putamen. Graft-mediated sprouting of host fibers was not observed. These data provide essential confirmation that, under appropriate transplant conditions, grafted nigral neurons can survive, reinnervate the host striatum, and provide clinical benefit to PD patients. These findings also support the concept that improved motor function and striatal FD uptake on PET after nigral grafting in PD are the result of the viability of grafted neurons and graft-derived reinnervation of the host striatum.

Bioenergetic defects and oxidative stress may be critical links in an excitotoxic mechanism of neuronal death. Oxidative stress, a condition describing the production of oxygen radicals beyond a threshold for proper antioxidant neutralization, has been implicated as a pathologic condition in several neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease. In addition, oxygen radicals are known to be important mediators in acute pathologies, in the theory of senescence, cancer, as well as our healthy immune system. Although free radicals may have a special chemical nature which allows them to perform important cellular functions, they are a damaging entity whose reactivity may play a part in the development of cellular compromises that can kill a neuron. In this review, the free radicals in biological systems, the defense systems against them, and the damaging interactions, i.e., oxidative stress, which they confer are discussed. The descriptions provided raise the hypothesis that an imbalance between the production and removal of radicals would be abrasive on a neuron. Accordingly, the neurodegeneration initially caused by gene mutation in Huntington's disease may be further worsened by free radical damage underlied by oxidative stress. This article reviews existing data on the free radical damage and the oxidative stress, which are primarily directed towards Parkinson's disease and Alzheimer's disease, and whenever possible relates such mechanisms to Huntington's disease.

Fetal neural transplantation has recently been demonstrated to ameliorate motor and other behavioral deficits in animals models of Huntington's disease, and reconstruct many of the damaged striatal circuits. However, there has been significant variability in the histological appearance of these grafts, most likely related to differences of the regions of dissection of the donor tissue. Selective dissection and transplantation of the lateral ventricular eminence in rodents has resulted in grafts consisting of primarily striatal-like tissue. This data, combined with data from our own and other laboratories has led to a description of the development of human striatum, with a particular emphasis on the relevance of human striatal development to the field of fetal tissue transplantation for the treatment of Huntington's disease. If the goal of transplantation is to graft GABAergic striatal projection neurons, it is our impression that optimal grafting results will occur when transplants are derived from the lateral ventricular eminence and the lateral aspect of the body of the ventricular eminence anterior to the foramen of Monro. Optimal results are likely to occur when donor ages range from Stage 19 to 23, with possible graft success when donor age extends to as late as postovulatory week 22.

Anatomical and behavioral characterizations of neural transplants, whether within (allograft) or across (xenograft) species, have provided evidence that the transplant survives, integrates with the host tissue, and may lead to functional recovery. Several animal models of neurodegenerative disorders demonstrate the feasibility of using neural transplantation as an alternative treatment for these human diseases. While more elaborate basic animal studies are needed, clinical trials have begun. Neural transplantation is currently used as an experimental treatment for Parkinson's disease and several investigators have suggested using the same treatment procedure for other neurodegenerative disorders, such as Huntington's and Alzheimer's disease.

Initially, the specific aim of transplantation studies was to investigate the regenerative capabilities of the mammalian nervous system. From this underlying impetus, a myriad of knowledge, spanning from molecular biology to neurobiology, has enhanced our understanding of regeneration and the applicability of fetal tissue transplantation in treating various neurodegenerative diseases. Current evidence suggests that transplantation of fetal neural tissue ameliorates the neurobiological and behavioral changes observed in animal models of central nervous system (CNS) disorders. In light of numerous basic science studies, clinical trials have begun to evaluate the potential of neural transplantation in treating human diseases. Indeed, modest progress has been reported in the treatment of Parkinson's disease. However, whereas fetal tissue transplantation has reached considerable success, it has also been observed to produce either no beneficial effects, magnify existing behavioral abnormalities, or even produce a unique constellation of deficits. Thus, while the prospects are promising, further investigations aimed at improving and refining existing transplantation paradigms are warranted before neural transplantation techniques can be of widespread value. This review article attempts to provide an overview of the neuroanatomical, neurochemical, and behavioral effects produced by transplanted fetal tissue in several animal models of CNS disorders. We have attempted to present both positive and adverse effects and to critically analyze the suitability of neural transplantation as a therapy for the various neurological disorders. In addition, alternative approaches, including the use of encapsulated neural tissue implants and genetically engineered cell lines along with their clinical potential, are discussed when appropriate.

In an open, nonblind study, 10 patients with Tourette's disorder who were being treated with haloperidol were videotaped before, while, and after chewing nicotine gum. The frequency of tics was reduced significantly during the 30-minute gum-chewing period and during the 1 hour after gum chewing. Nicotine appears to potentiate haloperidol effects in patients with Tourette's disorder.

Nicotine potentiates the catalepsy produced by haloperidol. Furthermore, nicotine as an adjunct to haloperidol produces a remarkable improvement in motor tics in Tourette's syndrome (TS) patients. The present experiments (1) compared the ability of nicotine to potentiate the catalepsy produced by haloperidol or the selective D1 dopamine receptor antagonist SCH 23390 and (2) examined the effects of various doses of nicotine (0.1, 0.2, or 0.3 mg/kg) on haloperidol-induced (0.1, 0.2, or 0.4 mg/kg) catalepsy and locomotor hypoactivity. In the first experiment, nicotine produced a five-fold increase in catalepsy following haloperidol but had no effect on the catalepsy produced by SCH 23390. In the second experiment, nicotine potentiated the cataleptic effects of both the 0.2 and 0.4 but not the 0.1 mg/kg dose of haloperidol. Haloperidol (0.1 and 0.4 mg/kg) also produced a dose-related decrease in locomotion that was significantly potentiated by nicotine (0.1 mg/kg). Nicotine alone did not produce catalepsy or any significant changes in locomotion. These results indicated that nicotine's potentiation of haloperidol-induced catalepsy is likely related to striatal D2 receptor mechanisms. Nicotine potentiated the locomotor effects of doses of haloperidol that were previously found to be subcataleptic, indicating that catalepsy testing may actually underestimate the behavioral interaction between haloperidol and nicotine. Nicotine may prove useful for treating neuroleptic responsive disorders such as TS, schizophrenia, and Huntington's disease.

Previous studies have suggested that human umbilical cord blood (HUCB) may serve as a rich source of hematopoietic and nonhematopoietic stem cells and that conditions exist that can coax hematopoietic cells to express neural characteristics. In our laboratory, these cells were tested for several models of neurodegenerative diseases and spinal cord injuries. Through a series of transplantation studies we have begun to uncover the properties of HUCB-derived cells in neuropoietic regions of the neonatal (1) and aging rodent brain. The systematic application of phenotyping approaches to characterize survival, migratory potential and morphologic properties of the differentiated HUCB progeny within normal/unaffected brain will serve as a base for understanding the potential effect of these cells in the diseased brain. Acknowledgements: Supported in part by R01 6155039 (TZ). HUCB cells were obtained from Saneron CCEL Therapeutics, Inc. and BioWhittaker, Inc.

Significant impairments in the acquisition and retention of a step-down passive avoidance task were found in rats with striatal lesions induced by the cholinergic neurotoxin AF64A. No significant differences between control and AF64A-injected rats were found in sensitivity to electric shock or in various measures of spontaneous locomotor activity. Striatal choline acetyltransferase (CAT) activity was significantly decreased in AF64A-treated rats compared with controls, whereas glutamic acid decarboxylase (GAD) activities were not. Furthermore, there were no significant differences between groups in activities of CAT and GAD in either the cortex or the hippocampus, results that support the specificity of the lesion to the striatum. The passive avoidance deficits found in these rats after intrastriatal injection of AF64A support a role for the striatal cholinergic system in complex behavioral processes.

Most automated methods of monitoring locomotion in animals have used mechanical equipment which measure only one dependent variable and are quite susceptible to a variety of experimental errors. Computer technology has advanced the mechanical means of measuring locomotor activity, allowing a new capability for simultaneously recording many aspects of locomotion. For example, the Digiscan System measures over 20 different indices of ambulatory, rearing, stereotypical and rotational behaviors over real time. Although standardization of some of these techniques is still needed, the computerized approach has already proven itself of value in neurobehavioral research. This paper describes the use of commercial systems in research.

The increased locomotor activity induced by systemic injections of d-amphetamine or scopolamine in rats was studied in Digiscan Animal Activity Monitors. This multifactorial analysis of locomotion demonstrated that activity measures of horizontal (ambulatory), vertical (rearing), stereotypic, and rotational behaviors differed depending on dose and drug. The topographies of these activity variables may be unique for the dopaminergic and cholinergic systems underlying hyperactivity. These results are a first step toward a needed increase in the sophistication of behavioral pharmacological techniques, allowing for the development of specific activity prints for different classes of psychoactive agents.

Behavioral effects of unilateral frontocortical suction lesions in the right and left hemisphere were characterized by a computerized activity monitoring system. Lesions of the right frontal cortex produced postoperative hyperactivity consisting of increases in the total distance traveled, average distance per movement, and average speed of movement. Vertical, rotational, and stereotypic measures were not changed. Animals receiving left hemisphere lesions did not differ from sham-operated controls on any behavioral variable. The lateralized hyperactivity resulting from lesions of the right frontal cortex was confined to increased length and speed of horizontal movement and did not appear to represent a generalized increase in all components of spontaneous activity.

Three variables constituting an index of rearing behavior from an animal-activity monitoring system were compared with a standard visual rating at various ages of neonatal and adult rats. All three automated measures correlated significantly with measures rated by visual observation, although only the "number of vertical episodes" was similar in magnitude to the actual number of observed rearings. The height of the vertical sensors was critical in detecting rearings, although reliable results were obtained over a relatively wide range of heights. Analyses in neonatal rats demonstrated developmental progression in rearing behavior, with an onset around Day 15 of age. This automated technique was found to be useful and eliminated confounding variables, such as experimenter bias, commonly associated with visual observation techniques.

Huntington's Disease (HD) is a progressive neurologic disorder transmitted as autosomal dominant. The symptoms of HD, which typically appear in midlife, include disturbances in movement, psychiatric symptoms, and a progressive dementia. Neuropathologic studies indicate a distinct pattern of neuronal degeneration in HD that affects many areas of the brain but consistently and severely involves the basal ganglia including the caudate, putamen, and globus pallidus. The basal ganglia undergo a progressive atrophy due to degeneration of intrinsic neurons that results in ventricular enlargement. Over the last decade, detailed neurochemical analyses have been carried out on the brains of patients who have died with HD. These studies have demonstrated the selective degeneration of chemically defined neuronal systems including the striatal cholinergic intrinsic neurons, the striatal nigral GABAergic pathway, and striatal peptidergic neurons with the relative sparing of other systems such as the nigrostriatal pathway. These findings have resulted in a better understanding of the pathophysiologic basis for the movement disorder of HD and have led to the development of pharmacologic strategies to correct the synaptic neurochemical imbalances. Recent studies have begun to focus on mechanisms responsible for the selective neuronal degeneration in HD. One promising hypothesis evolved from the finding that intrastriatal injections of excitatory amino acid analogues reproduces the neurochemical and histologic pathology of HD in experimental animals; as a consequence, it has been hypothesized that dysfunction of excitatory amino acid neurotransmission may cause the selective neuronal degeneration of HD. Another hypothesis involves an abnormality of the plasma membrane based upon observations of differences in membrane characteristics in fibroblasts and red blood cells from HD patients as compared to suitable controls. The ultimate goals of these studies are to develop methods for identifying presymptomatic carriers of the HD gene as well as strategies for preventing the neuronal degeneration associated with expression of the gene.

The typical catalepsy test consists of placing an animal into an unusual posture and recording the time taken to correct this posture. This time is regarded as an index of the intensity of catalepsy. Catalepsy is a robust behavior, and the lack of standardization does not usually hinder its actual detection. However, the intensity of the cataleptic effect is influenced by minor methodological differences, and thus interpretation and comparison of results across laboratories are difficult. The behavioral catalepsy test can use any of several different apparatus, including wire grids, parallel bars, platforms, or pegs, to situate the animals in unusual positions. The most common, however, is the "bar test," and despite its wide use in psychopharmacological research, even parameters of this test are not standardized. The present article reviews the wide variety of parameters chosen by investigators that measure catalepsy. The methodological issues of repeated testing, scaling of scores, apparatus, animal weight, maximal test duration, behavioral criteria, and other influences are discussed. In addition, a brief review of the neuropharmacological basis of catalepsy is also included. Finally, it is argued that a universal, standardized bar test be adopted by researchers. New data on a novel automated bar test in the Digiscan Activity Monitoring System is presented.

The dopamine receptor agonist apomorphine enhanced motor activity as measured in stabilimeters and decreased the duration of tonic immobility behavior in chickens in a dose-dependent manner. Haloperidol, a dopamine receptor antagonist, increased the duration of tonic immobility and attenuated the apomorphine-induced increase in activity. Motor activity could also be increased by the cholinergic antagonist scopolamine. In addition, scopolamine was shown to decrease the duration of tonic immobility. On the other hand, the cholinergic agonist pilocarpine increased tonic immobility behavior and decreased scopolamine's effect on motor activity in these birds. Studies of the interaction of dopaminergic and cholinergic systems showed that haloperidol could attenuate the activity-stimulating effects of scopolamine whereas pilocarpine had a similar, but lesser, effect on apomorphine-induced activity. The results support the suggestion that in birds, as in mammals, the dopaminergic and cholinergic systems are intimately involved in the expression of motor behavior.