Hereditary progressive dystonia with marked diurnal fluctuation caused by mutations in the GTP cyclohydrolase I gene.

Hereditary progressive dystonia with marked diurnal fluctuation (HPD) (also known as dopa responsive dystonia) is a dystonia with onset in childhood that shows a marked response without any side effects to levodopa. Recently the gene for dopa responsive dystonia (DRD) was mapped to chromosome 14q. Here we report that GTP cyclohydrolase I is mapped to 14q22.1-q22.2. The identification of four independent mutations of the gene for GTP cyclohydrolase I in patients with HPD, as well as a marked decrease in the enzyme's activity in mononuclear blood cells, confirms that the GTP cyclohydrolase I gene is a causative gene for HPD/DRD. This is the first report of a causative gene for the inherited dystonias.

Synaptic integration mediated by striatal cholinergic interneurons in basal ganglia function.

The physiological role of striatal cholinergic interneurons was investigated with immunotoxin-mediated cell targeting (IMCT). Unilateral cholinergic cell ablation caused an acute abnormal turning behavior. These mice showed gradual recovery but displayed abnormal turning by both excess stimulation and inhibition of dopamine actions. In the acute phase, basal ganglia function was shifted to a hyperactive state by stimulation and suppression of striatonigral and striatopallidal neurons, respectively. D1 and D2 dopamine receptors were then down-regulated, relieving dopamine-predominant synaptic perturbation but leaving a defect in controlling dopamine responses. The acetylcholine-dopamine interaction is concertedly and adaptively regulated for basal ganglia synaptic integration.

H(2)O(2) increases de novo synthesis of (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin via GTP cyclohydrolase I and its feedback regulatory protein in vitiligo.

Patients with vitiligo accumulate up to 10(-3) mol/L concentrations of H(2)O(2) in their epidermis, which in turn affects many metabolic pathways in this compartment, including the synthesis and recycling of the cofactor (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin (6BH(4)). De novo synthesis of 6BH(4) is dependent on the rate-limiting enzyme GTP cyclohydrolase I (GTPCHI) together with its feedback regulatory protein (GFRP). This step is controlled by 6BH(4) and the essential amino acid L-phenylalanine. In the study presented here we wanted to investigate whether H(2)O(2) affects the GTPCHI/GFRP cascade in these patients. Our results demonstrated concentration-dependent regulation of rhGTPCHI where 100 micromol/L H(2)O(2) was the optimum concentration for the activation of the enzyme and >300 micromol/L resulted in a decrease in activity. Oxidation of GFRP and GTPCHI does not affect feedback regulation via L-phenylalanine and 6BH(4). In vitiligo a constant upregulation of 6BH(4) de novo synthesis results from epidermal build up of L-phenylalanine that is not controlled by H(2)O(2). Taking the results together, 6BH(4) de novo synthesis is controlled by H(2)O(2) in a concentration-dependent manner, but H(2)O(2)-mediated oxidation does not affect the functionality of the GTPCHI/GFRP complex.

The pulmonary vasopressor response to decreases in blood pH in intact dogs.

The pulmonary vasopressor response to acidemia was studied in intact dogs in a hemodynamically separated lobe which was pump perfused with systemic arterial or venous blood at a fixed rate. The magnitudes of the lobar vasopressor responses to perfusion with blood rendered acidic by infusions of hydrochloric lactic, and acetic acids, and by hypercapnia (membrane oxygenator) were significantly different. Although the PH of the perfusing blood in each group fell to similar extents (pH 7.1-7.0), the lobar pressor response was greatest with hydrochloric acid (HCl), smaller with lactic and acetic acids, and absent with hypercapnia. A lobar vasopressor response also occurred during lobar perfusion with blood which had been extracorporeally acidified with HCl or acetic acid, but then returned to control pH by infusions of sodium bicarbonate and Tris before reaching the lung. A lobar vasopressor response also resulted from pump perfusion of the lobar artery with femoral venous blood during perfusion of the isolated ipsilateral femoral artery with similarly treated aortic blood. However, no lobar vasopressor response resulted from pump perfusion of the lobar artery with blood removed transseptally from a right pulmonary vein during acidification (HCl) of the right pulmonary artery (to pH 7.0).The data indicate that, in this experimental preparation involving closed-chest dogs spontaneously breathing air or 35% oxygen, the lobar vasopressor response to infusions of acidifying agents is not directly related to the pH of blood actually perfusing the lobar vessels. Additionally, the vasopressor response is prevented by prior perfusion of the acidified blood through a pulmonary vascular bed but not by prior perfusion through the femoral vascular bed. Although these experiments do not establish the mediation of the lobar vasopressor response, activation of vasoactive agents in blood at or near the acidification site is suggested. In these experiments, the acidemia was produced under conditions which are not like the usual ones of developing metabolic acidosis or alveolar hypercapnia, in that strong acids were directly infused into blood which perfused only one lung lobe. The mediation of the present pressor responses and of those found in the more usual forms of experimental and clinical acidosis may therefore be dissimilar.

SNF2beta-BRG1 is essential for the viability of F9 murine embryonal carcinoma cells.

The yeast and animal SNF-SWI and related multiprotein complexes are thought to play an important role in processes, such as transcription factor binding to regulatory elements, which require nucleosome remodeling in order to relieve the repressing effect of packaging DNA in chromatin. There are two mammalian homologs of the yeast SNF2-SWI2 subunit protein, SNF2alpha-brm and SNF2beta-BRG1, and overexpression of either one of them has been shown to enhance transcriptional activation by glucocorticoid, estrogen, and retinoic acid (RA) receptors in transiently transfected cells. We have investigated here the function of SNF2beta-BRG1 in the RA receptor-retinoid X receptor-mediated transduction of the retinoid signal in F9 embryonal carcinoma (EC) cells which differentiate into endodermal-like cells upon RA treatment. The two SNF2beta-BRG1 alleles have been targeted by homologous recombination and subsequently disrupted by using a conditional Cre recombinase. We show that F9 EC cells inactivated on both SNF2beta alleles are not viable and that heterozygous mutant cells are affected in proliferation but not in RA-induced differentiation. Thus, in F9 EC cells, SNF2beta-BRG1 appears to play an essential role in basal processes involved in cell proliferation, in addition to its putative role in the activation of transcription mediated by nuclear receptors.

Macrophage-mediated destruction of human malignant cells in vivo.

Macrophages require a plasma component, designated "recognition factor" (RF), for the expression of optimal function. The RF activity was profoundly depleted in plasma from patients with malignant disease, and the degree of depletion and the severity of the malignant state seemed to be related. Since experiments demonstrated that an active RF significantly inhibited tumor growth, clinical studies were initiated to investigate the influence of intratumor administration of an active RF fraction. Glucan, a potent macrophage activator, was also employed alone or combined with RF. These studies were undertaken to enhance the recognition of malignant cells by macrophages and to mobilize and activate macrophages intralesionally. The initial 9 patients studied had malignant melanoma, adenosquamous carcinoma of the lung, or carcinoma of the breast. Control and experimental lesions were injected; subsequently biopsies were performed at varying intervals for histologic evaluation. Always when glucan or glucan and RF fraction were administered intralesionally, the size of the lesion was strikingly reduced in as short a period as 5 days. This reduction was associated with necrosis of the tumor and a monocytic infiltrate. In small lesions, resolution was complete, whereas in large lesions, resolution was partial. The amount of glucan injected and the quantity of residual tumor appeared to be related. The induced necrosis of the tumor nodule was associated with an increase in plasma levels of circulating RF activity.

Delayed hypersensitivity to 5-fluorouracil following topical chemotherapy of cutaneous cancers.

Skin tests to various common antigens, dinitrochlorobenzene, and 5-fluorouracil (5-FU) were performed on patients being treated for cutaneous neoplasms with topical 5-FU cream. Eleven of 15 patients tested both before and after therapy converted from skin test negative to positive with respect to 5-FU. This conversion correlated with positive dinitrochlorobenzene skin tests and therapeutic cure. The relation between the induction of delayed hypersensitivity reactions to 5-FU following treatment with topical 5-FU and the cure rate for cutaneous neoplasms showed a trend toward correlation.

Reversible squamous cell characteristics induced by vitamin A deficiency in a small cell lung cancer cell line.

A cultured small cell lung cancer cell line (Lu-134-B-S) established from a xenotransplanted tumor in a nude mouse, which had originated from a primary focus of small cell lung cancer, showed morphological changes when the medium was changed from RPMI 1640 supplemented with 10% fetal calf serum to RPMI 1640 supplemented with 10% delipidized fetal calf serum. That is, it consisted of "classic" small cells in the former medium, but after eight passages in the latter medium many cells became squamous cells, possessing abundant eosinophilic cytoplasm and intercellular bridges. Immunohistochemically, they reacted to antikeratin and antiinvolucrin antibodies. Electron microscopically, well developed desmosomes and associated tonofibrils were noted, and electrophoretically, the amount of medium (Mr 57,000 and 59,000) and large-sized (Mr 67,000) keratins were found to increase with the change of the medium. These changes reversed to the original small cell morphology within 4 weeks after addition of vitamin A (retinoic acid) to the medium. These findings suggested that deficiency of vitamin A caused the change of the cell from small to squamous cell and vice versa.

The potential histogenic relationship of the peripheral nerve to synovioma.

The belief that synoviomas differentiate from the synovial membrane has been widely accepted. Absolute proof is lacking, mainly because precancerous synovial atypia has not been documented in human tissue. During the last 50 years, pain has emerged as one of the significant features of synovioma, occurring very early in the course of the disease in some patients. Gross relationship to nerve, cumulative histological data, and theoretical relationships with three other cancers of neural origin suggest the nerve sheath as an alternate parent tissue for synovioma. Three cases illustrating nerve involvement are included.

Mouse sepiapterin reductase: an enzyme involved in the final step of tetrahydrobiopterin biosynthesis. Primary structure deduced from the cDNA sequence.

We carried out the cloning of a mouse cDNA encoding a sepiapterin reductase which is involved in the final step of tetrahydrobiopterin biosynthesis as a first step toward gene-targeting technique in mice. The sequence contained 1245 nucleotides consisting of an open reading frame of 783 nucleotides encoding a protein of 261 amino acid residues whose molecular weight was 27,851, a 5'-untranslated region of 21 nucleotides and a 3'-untranslated region of 441 nucleotides containing poly(A) tail. The amino acid sequence of mouse sepiapterin reductase revealed the identity of 88% with rat and 74% with human sequence.

Comparison of characteristics of bovine aromatic L-amino acid decarboxylase with human enzyme.

Aromatic L-amino acid decarboxylase (AADC) was purified from bovine adrenal medulla and properties of this enzyme were compared with those of AADC from human pheochromocytoma. The molecular weights of the subunits were identical between human and bovine enzymes and estimated to be 50,000 by SDS-polyacrylamide gel electrophoresis. An isoelectric point of the human enzyme was 5.7, while the bovine enzyme showed several distinct bands at the region of pH 4.9-5.3 in the absence of urea. Multiplicity of the isoelectric point of bovine AADC disappeared in the presence of urea. These results showed that there were some differences between the properties of human and bovine AADC in spite of the high homology (88%) in their primary structures.

Functionally important residues tyrosine-171 and serine-158 in sepiapterin reductase.

The active site of sepiapterin reductase (SPR), which is a member of the NADP(H)-preferring short-chain dehydrogenase/reductase (SDR) family and acts as the terminal enzyme in the biosynthetic pathway of tetrahydrobiopterin cofactor (BH4), was investigated by truncation and site-directed mutagenesis. The truncation mutants showed that N-terminal and C-terminal residues contribute to bind coenzyme and substrate, respectively. The mutant rSPRA29V showed decreased activity; however, the A-X-L-L-S sequence, which has been reported as a putative pterin binding site, was estimated to preferably work as a component in the region for binding coenzyme rather than substrate. Site-directed mutants of rSPRS158D, rSPRY171V, and rSPRK175I showed low, but significant, activity having similar Km values and kcat/Km values less than 25%, for both sepiapterin and NADPH. Both amino acids Tyr-171 and Ser-158 are located within a similar distance to the carbonyl group of the substrate in the crystal structure of mouse SPR, and the double point mutant rSPRY171V+S158D was indicated to be inactive. These results showed that Ser-158, Tyr-171, and Lys-175 contributed to the catalytic activity of SPR, and both Tyr-171 and Ser-158 are simultaneously necessary on proton transfer to the carbonyl functional groups of substrate.

Behavioral recovery in 6-hydroxydopamine-lesioned rats by cotransduction of striatum with tyrosine hydroxylase and aromatic L-amino acid decarboxylase genes using two separate adeno-associated virus vectors.

Parkinson's disease (PD) is characterized by the progressive loss of the dopaminergic neurons in the substantia nigra and a severe decrease in dopamine in the striatum. A promising approach to the gene therapy of PD is intrastriatal expression of enzymes in the biosynthetic pathway for dopamine. Tyrosine hydroxylase (TH) catalyzes the synthesis of L-dopa, which must be converted to dopamine by aromatic L-amino acid decarboxylase (AADC). Since the endogenous AADC activity in the striatum is considered to be low, coexpression of both TH and AADC in the same striatal cells would increase the dopamine production and thereby augment the therapeutic effects. In the present study, the TH gene and also the AADC gene were simultaneously transduced into rat striatal cells, using two separate adeno-associated virus (AAV) vectors, AAV-TH and AAV-AADC. Immunostaining showed that TH and AADC were coexpressed efficiently in the same striatal cells in vitro and in vivo. Moreover, cotransduction with these two AAV vectors resulted in more effective dopamine production and more remarkable behavioral recovery in 6-hydroxydopamine (6-OHDA)-lesioned rats, compared with rats receiving AAV-TH alone (p < 0.01). These findings suggest an alternative strategy for gene therapy of PD and indicate that the simultaneous transduction with two AAV vectors can extend their utility for potential gene therapy applications.

Triple transduction with adeno-associated virus vectors expressing tyrosine hydroxylase, aromatic-L-amino-acid decarboxylase, and GTP cyclohydrolase I for gene therapy of Parkinson's disease.

Parkinson's disease (PD), a neurological disease suited to gene therapy, is biochemically characterized by a severe decrease in the dopamine content of the striatum. One current strategy for gene therapy of PD involves local production of dopamine in the striatum achieved by inducing the expression of enzymes involved in the biosynthetic pathway for dopamine. We previously showed that the coexpression of tyrosine hydroxylase (TH) and aromatic-L-amino-acid decarboxylase (AADC), using two separate adeno-associated virus (AAV) vectors, resulted in more effective dopamine production and more remarkable behavioral recovery in 6-hydroxydopamine-lesioned parkinsonian rats, compared with the expression of TH alone. Not only levels of TH and AADC but also levels of tetrahydrobiopterin (BH4), a cofactor of TH, and GTP cyclohydrolase I (GCH), a rate-limiting enzymes for BH4 biosynthesis, are reduced in parkinsonian striatum. In the present study, we investigated whether transduction with separate AAV vectors expressing TH, AADC, and GCH was effective for gene therapy of PD. In vitro experiments showed that triple transduction with AAV-TH, AAV-AADC, and AAV-GCH resulted in greater dopamine production than double transduction with AAV-TH and AAV-AADC in 293 cells. Furthermore, triple transduction enhanced BH4 and dopamine production in denervated striatum of parkinsonian rats and improved the rotational behavior of the rats more efficiently than did double transduction. Behavioral recovery persisted for at least 12 months after stereotaxic intrastriatal injection. These results suggest that GCH, in addition to TH and AADC, is important for effective gene therapy of PD.

Regulation of pteridine-requiring enzymes by the cofactor tetrahydrobiopterin.

Tetrahydrobiopterin (BH4) is synthesized from guanosine triphosphate (GTP) by GTP cyclohydrolase I (GCH), 6-pyruvoyltetrahydropterin synthase (PTS), and sepiapterin reductase (SPD). GCH is the rate-limiting enzyme. BH4 is a cofactor for three pteridine-requiring monooxygenases that hydroxylate aromatic L-amino acids, i.e., tyrosine hydroxylase (TH), tryptophan hydroxylase (TPH), and phenylalanine hydroxylase (PAH), as well as for nitric oxide synthase (NOS). The intracellular concentrations of BH4, which are mainly determined by GCH activity, may regulate the activity of TH (an enzyme-synthesizing catecholamines from tyrosine), TPH (an enzyme-synthesizing serotonin and melatonin from tryptophan), PAH (an enzyme required for complete degradation of phenylalanine to tyrosine, finally to CO2 + H2O), and also the activity of NOS (an enzyme forming NO from arginine), Dominantly inherited hereditary progressive dystonia (HPD), also termed DOPA-responsive dystonia (DRD) or Segawa's disease, is a dopamine deficiency in the nigrostriatal dopamine neurons, and is caused by mutations of one allele of the GCH gene. GCH activity and BH4 concentrations in HPD/DRD are estimated to be 2-20% of the normal value. By contrast, recessively inherited GCH deficiency is caused by mutations of both alleles of the GCH gene, and the GCH activity and BH4 concentrations are undetectable. The phenotypes of recessive GCH deficiency are severe and complex, such as hyperphenylalaninemia, muscle hypotonia, epilepsy, and fever episode, and may be caused by deficiencies of various neurotransmitters, including dopamine, norepinephrine, serotonin, and NO. The biosynthesis of dopamine, norepinephrine, epinephrine, serotonin, melatonin, and probably NO by individual pteridine-requiring enzymes may be differentially regulated by the intracellular concentration of BH4, which is mainly determined by GCH activity. Dopamine biosynthesis in different groups of dopamine neurons may be differentially regulated by TH activity, depending on intracellular BH4 concentrations and GCH activity. The nigrostriatal dopamine neurons may be most susceptible to a partial decrease in BH4, causing dopamine deficiency in the striatum and the HPD/DRD phenotype.

Ligand-dependent interaction between the estrogen receptor and the human homologues of SWI2/SNF2.

The human SNF2alpha (or hbrm) and SNF2beta (or BRG1) proteins have previously been shown to enhance transcriptional activation by nuclear receptors (NRs) in cultured human cells, and to be present in SWI/SNF complexes which are thought to be involved in control of transcription by facilitating remodelling of chromatin templates. Using the yeast two-hybrid system, we now demonstrate that the N-terminal regions of hSNF2alpha and hSNF2beta, preceding the DNA-dependent ATPase domain, specifically interact with the region of the estrogen receptor (ER) which includes the ligand binding domain and the ligand-dependent activation function AF-2. These interactions are increased by estrogen, but not by the ER AF-2 antagonist hydroxytamoxifen. Furthermore, mutants of ER that lack AF-2 activity are unable to interact with hSNF2alpha and -beta. These results suggest that the human homologues of the yeast SWI2/SNF2 protein may participate in the enhancement of transcription by the ER in vivo through interactions with the AF-2 activating domain, thus leading to ligand-dependent remodelling of chromatin templates.

Molecular cloning of the human Nurr1 gene: characterization of the human gene and cDNAs.

Nurr1 is a member of the nuclear receptor superfamily of transcription factors that is expressed predominantly in the central nervous system, including developing dopaminergic neurons. Recently, it was demonstrated that Nurr1 is critical for midbrain dopaminergic cell differentiation. In order to investigate a possible relation of Nurr1 with the pathogenesis of Parkinson's disease or other neuropsychiatric disorders, we have cloned and characterized the human Nurr1 gene. The gene exists as a single copy in the human genome and comprises eight exons spanning 8kb. We determined the complete nucleotide sequence and flanking regions of the gene. Potential regulatory regions included consensus binding sites for NF-kappaB, CREB, and Sp1. Isolation of human Nurr1 cDNAs from fetal brain suggested the presence of a new splicing variant of Nurr1 in the human brain.

Fungal cleavage of thioether bond found in Yperite.

The degradation of thiodiglycol (I) and benzyl sulfide (II) was attempted using Coriolus versicolor and Tyromyces palustris to investigate the potential ability of basidiomycetes to degrade Yperite (bis(2-chloroethyl) sulfide), a mass-produced and stored chemical warfare agent. I was very rapidly degraded by both fungi. The metabolic pathway of II was elucidated, showing that the initial step was the hydrolytic cleavage of the thioether bond to yield benzyl alcohol and benzyl mercaptan. Benzyl alcohol was further oxidized and finally mineralized. Benzyl mercaptan is reversibly converted to benzyl disulfide and also converted to benzyl alcohol. Finally, the effective degradation of bis(2-bromoethyl) sulfide strongly suggests that basidiomycete would be a potential tool for Yperite degradation.

Neuroleptic malignant syndrome with prolonged catatonia in a dopa-responsive dystonia patient.

The authors describe a patient with dopa-responsive dystonia who developed neuroleptic malignant syndrome with prolonged catatonia following treatment with neuroleptic agents. Use of these agents probably expanded the patient's neuronal dysfunction beyond the nigrostriatal system to involve multiple dopaminergic systems. Electroconvulsive treatment alleviated the prolonged catatonia.

Plantar lentiginous melanoma: a distinctive variant of human cutaneous malignant melanoma.

The neoplastic system of human cutaneous melanoma includes three generaly recognized variants: lentigo maligna, superficial spreading melanoma, and nodular melanoma. Lentiginous melanomas other than lentigo maligna constitute a fourth group, of which plantar lentiginous melanoma qualifies as an anatomic subgroup. Histologically and clinically, plantar lentiginous melanoma (PLM) is characterized by a period of radial growth and often by one or more foci of regression. In 27 of 33 plantar melanomas, a characteristic lentiginous, radial component of melanocytic proliferation was noted. In the remaining six cases, histological material failed to document a radial component. Eighteen of the 27 patients with PLM were blacks, and 18 patients died of distant metastasis. Tumors invasive to level II did not metastasize, but at levels IV and V and in tumors with a high mitotic rate, the prognosis was poor. The presence of lymph node metastases at the time of initial therapy correlated with a poor prognosis group.