The differentiation of prehypertrophic into hypertrophic chondrocytes drives an OA-remodeling program and IL-34 expression.

OBJECTIVES: We hypothesize that chondrocytes from the deepest articular cartilage layer are pivotal in maintaining cartilage integrity and that the modification of their prehypertrophic phenotype to a hypertrophic phenotype will drive cartilage degradation in osteoarthritis. DESIGN: Murine immature articular chondrocytes (iMACs) were successively cultured into three different culture media to induce a progressive hypertrophic differentiation. Chondrocyte were phenotypically characterized by whole-genome microarray analysis. The expression of IL-34 and its receptors PTPRZ1 and CSF1R in chondrocytes and in human osteoarthritis tissues was assessed by RT-qPCR, ELISA and immunohistochemistry. The expression of bone remodeling and angiogenesis factors and the cell response to IL-1ß and IL-34 were investigated by RT-qPCR and ELISA. RESULTS: Whole-genome microarray analysis showed that iMACs, prehypertrophic and hypertrophic chondrocytes each displayed a specific phenotype. IL-1ß induced a stronger catabolic effect in prehypertrophic chondrocytes than in iMACs. Hypertrophic differentiation of prehypertrophic chondrocytes increased Bmp-2 (95%CI [0.78; 1.98]), Bmp-4 (95%CI [0.89; 1.59]), Cxcl12 (95%CI [2.19; 5.41]), CCL2 (95%CI [3.59; 11.86]), Mmp 3 (95%CI [10.29; 32.14]) and Vegf mRNA expression (95%CI [0.20; 1.74]). Microarray analysis identified IL-34, PTPRZ1 and CSFR1 as being strongly overexpressed in hypertrophic chondrocytes. IL-34 was released by human osteoarthritis cartilage; its receptors were expressed in human osteoarthritis tissues. IL-34 stimulated CCL2 and MMP13 in osteoblasts and hypertrophic chondrocytes but not in iMACs or prehypertrophic chondrocytes. CONCLUSION: Our results identify prehypertrophic chondrocytes as being potentially pivotal in the control of cartilage and subchondral bone integrity. Their differentiation into hypertrophic chondrocytes initiates a remodeling program in which IL-34 may be involved.

Acute exanthemas: a prospective study of 98 adult patients with an emphasis on cytokinic and metagenomic investigation.

BACKGROUND: Acute exanthemas (AEs) are frequently seen; they can be caused by drugs or viruses but often the cause is unknown. OBJECTIVES: To describe the clinical, virological and histological aspects of AEs and explore their cytokinic and metagenomic profiles. METHODS: This prospective study examined 98 patients with AE, from February to July 2014. Clinical data were recorded in a standardized chart. Virological investigation and skin biopsies were performed. In addition, blood and skin samples were analysed for cytokines and then by a shotgun metagenomic approach. We identified five groups of patients: those with maculopapular exanthemas (MPEs) that were virally induced (group 1); those with drug-induced MPEs (group 2), those with MPEs that were both viral and drug induced (group 3), those with idiopathic MPEs (group 4) and those with pityriasis rosea (group 5). RESULTS: A virus was identified in 29 cases (human herpesvirus 6, 72%). Cytokinic analysis of the skin (n = 23 MPEs) showed higher levels of interferon-γ and interleukin-1 receptor-α in viral MPEs, higher interleukin-33 levels in idiopathic MPEs, and higher macrophage inflammatory protein 1α levels in drug-induced MPEs. By metagenomics analysis (n = 10 MPEs), viruses identified with routine practice methods were not found in group 1 (n = 4 MPEs). However, Enterovirus A was detected in two cases, especially in a group 1 patient for whom metagenomic analysis rectified the diagnosis of the culprit agent. CONCLUSIONS: Human herpesvirus 6 was the virus most frequently identified, and histology did not discriminate MPEs. In addition, the level of interleukin-33 seen in idiopathic MPEs suggests that an environmental factor may be the trigger for these. The results bring into question the utility of routine polymerase chain reaction analysis and viral serology for determining cause in AE. What's already known about this topic? Acute exanthemas, especially maculopapular exanthemas, are a frequent reason for patients consulting emergency and dermatology departments. It is difficult to evaluate the aetiology of acute exanthema based on the clinical aspects. Few data are available on the investigations needed in routine practice, and no prospective series have been published. What does this study add? Our study provides a global and prospective description of acute exanthemas. Cytokine analysis could help to investigate the pathophysiology of idiopathic eruptions. Metagenomic analysis provides new insights about the value of routine practice virological investigations. We show for the first time the feasibility of metagenomics analysis in the skin, which results question the interest of routine PCR and viral sérologies for the exploration of such acute exanthemas.

Publisher Correction: Ice sheets matter for the global carbon cycle.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Ice sheets matter for the global carbon cycle.

The cycling of carbon on Earth exerts a fundamental influence upon the greenhouse gas content of the atmosphere, and hence global climate over millennia. Until recently, ice sheets were viewed as inert components of this cycle and largely disregarded in global models. Research in the past decade has transformed this view, demonstrating the existence of uniquely adapted microbial communities, high rates of biogeochemical/physical weathering in ice sheets and storage and cycling of organic carbon (>104 Pg C) and nutrients. Here we assess the active role of ice sheets in the global carbon cycle and potential ramifications of enhanced melt and ice discharge in a warming world.

Preferential association of human papillomavirus with high-grade histologic variants of penile-invasive squamous cell carcinoma.

BACKGROUND: Human papillomavirus (HPV) is causally associated with cervical squamous cell carcinoma (SCC) and its precursor lesions. By analogy, HPV is believed to play a role in penile cancer through progression of HPV-associated penile squamous intraepithelial lesions (SIL). HPV DNA has been reported to be present in 100% of high-grade penile SIL, but the percentage of invasive or infiltrating penile SCC that was positive for HPV DNA has varied from study to study (positivity values ranging from 32% to 82%). PURPOSE: To ascertain whether HPV is associated with penile cancer, we used a polymerase chain reaction (PCR)-based assay to test specimens of penile SCC for the presence of HPV DNA. METHODS: A total of 117 formalin-fixed, paraffin-embedded specimens of penile cancer from an equal number of patients who had been diagnosed either at the Memorial Sloan-Kettering Cancer Research Center in New York City between 1964 and 1992 or the Universidad Nacional de Asunción in Paraguay between 1980 and 1992 were analyzed. Specimens were examined without prior knowledge of the histology of the lesions. Methods were used that minimized sample contamination, thus avoiding false-positive results. PCR and Southern blot analyses were used to determine HPV type. The presence of HPV DNA was studied for association with the tumor properties histopathology, growth pattern, tumor grade, regional lymph node status, and anatomic location. Two-sided statistical tests were used to determine P values. RESULTS: HPV DNA was detected in 26 (22.2%) of 117 specimens. In 23 (88.5%) of the 26 HPV-positive specimens, HPV type 16 (only) was identified. HPV DNA was frequently associated with SCC in areas showing basaloid and/or warty changes (nine [47.4%] of 19 specimens were HPV positive; P = .0125). More highly significant was the association of virus with basaloid SCC (nine [75%] of 12 specimens were HPV positive; P = .0005). However, HPV was not found to be associated with typical SCC of the penis (five [11.1%] of 45 specimens were HPV positive). Virus DNA was more often associated with high-grade tumors (P = .0278) exhibiting aggressive growth (P = .0382) localized to the glans penis (P = .0324). Stepwise logistic regression analysis revealed that only tumor histopathology was a significant predictor of an HPV association. CONCLUSIONS: The presence of HPV DNA was found to be significantly associated only with those penile SCC exhibiting basaloid changes. Furthermore, HPV DNA sequences tended to be associated with higher grade and more aggressive tumor localized to the glans penis. The low frequency of HPV in penile SCC implies that only a small proportion of these cancers arise from HPV-associated penile SIL.

Serotonin hyperinnervation of the striatum with high synaptic incidence in parkinsonian monkeys.

The chronic use of L-Dopa for alleviating the motor symptoms of Parkinson's disease often produces adverse effects such as dyskinesia. Unregulated release of dopamine by serotonin axons following L-Dopa administration is a major presynaptic determinant of these abnormal involuntary movements. The present study was designed to characterize the reorganization of serotonin striatal afferents following dopaminergic denervation in a primate model of Parkinson's disease. Our sample comprised eight cynomolgus monkeys: four that were rendered parkinsonian following MPTP administration and four controls. The state of striatal serotonin and dopamine innervation was evaluated by means of immunohistochemistry with antibodies against serotonin transporter (SERT) and tyrosine hydroxylase. A detailed stereological investigation revealed a significant increase in the number of serotonin axon varicosities in the striatum of MPTP-intoxicated monkeys. This increase is particularly pronounced in the sensorimotor territory of the striatum, where the dopamine denervation is the most severe. Electron microscopic examinations indicate that, in contrast to the nucleus accumbens where the dopamine innervation is preserved, the SERT+ axon varicosities observed in the sensorimotor territory of the putamen establish twice as many synaptic contacts in MPTP-intoxicated monkeys than in controls. These findings demonstrate the highly plastic nature of the serotonin striatal afferent projections, a feature that becomes particularly obvious in the absence of striatal dopamine. Although the number of dorsal raphe serotonin neurons remains constant in parkinsonian monkeys, as shown in the present study, their ascending axonal projections undergo marked proliferative and synaptic adaptive changes that might play a significant role in the potential unregulated and ectopic release of dopamine by serotonin axons after L-Dopa treatment of Parkinson's disease.

Spontaneous malignant transformation of human ovarian surface epithelial cells in vitro.

PURPOSE: Epithelial ovarian cancer has no reliable marker for early detection and no known specific premalignant changes. Human ovarian surface epithelial (HOSE) cells expressing human papillomavirus type 16 (HPV-16) E6/E7 genes undergo crisis, and surviving cells exhibit an immortalized phenotype. Cells show an increasingly invasive phenotype on collagen rafts over time. To ascertain the nature of this aberrant growth, we characterized this spontaneous progression of HOSE cells from a benign to an invasive phenotype using histopathology, immunophenotyping, and tumorigenesis assays. EXPERIMENTAL DESIGN: At various passages, cells were monitored for growth on collagen, response to tumor necrosis factor alpha and daunorubicin, immunohistochemistry and Western blot analysis of E-cadherin and beta-catenin, growth in soft agar, and tumor formation in immunodeficient mice. RESULTS: As passage number increased, cells became increasingly aggressive on collagen, with more pronounced focal stratification and invasion. Furthermore, late-passage cells were more resistant to the apoptotic effects of TNF-alpha and daunorubicin than earlier-passage cells. E-cadherin expression was limited to early-passage cells, whereas beta-catenin was expressed regardless of passage. Cells invading collagen formed colonies in soft agar at low efficiency but were not tumorigenic in immunodeficient mice. Some cultures recovered from colonies grew in soft agar at high efficiencies, and one was tumorigenic. CONCLUSIONS: HOSE cells expressing E6/E7, over time, develop characteristics of malignant cells and produce tumors consistent with an ovarian surface epithelium lineage. Progression of HOSE cells from a benign to an invasive phenotype in vitro may provide a model to dissect the progression of ovarian cancer.

Comparison of human papillomavirus genotypes in archival cervical cancer specimens from Alaska natives, Greenland natives and Danish Caucasians.

Archival, formalin-fixed, paraffin-embedded cervical cancer specimens from 53 Alaska natives, 32 Greenland natives and 34 Danish Caucasians were analyzed for human papillomavirus (HPV) genotypes 16, 18, 31, 33, 35 and 45 and unidentified genotypes (HPV X) using PCR. The specimens were from the time period 1980-1989. No significant differences were observed in the overall HPV detection rates among cases from Alaska (98.1%), Greenland (84.4%) and Denmark (85.3%). HPV genotype 16 was the most prevalent type: 78.8% in Alaska natives, 96.3% in Greenland natives and 82.8% in Danish Caucasians. A prevalence of 21.2% HPV 31 and 30.8% HPV 33 was found in Alaska natives, of which most were coinfections with HPV 16. Only 3.7% HPV 31 and 3.7% HPV 33 were found in Greenland natives and no HPV 31 and 6.9% HPV 33 were found in Danish Caucasians. HPV 18 was only detected in Alaska natives and HPV 35 and 45 were not detected in any of the three populations. Infections with multiple genotypes were prevalent in Alaskan (36.5%) but not in Greenland natives (3. 7%) and Danish Caucasians (6.9%). The Eskimo subgroup of the Alaska native population has a significantly higher prevalence of HPV genotypes 31 and 33 associated with mixed infections in invasive cancer than the two other native subgroups (P = 0.04) and Greenland and Danish populations, reflecting genotype distributions in dysplasia and normal cervical cytology. The reason for HPV genotype diversity, although unknown, may be relevant to the current development of HPV vaccines.

D1 receptor blockade improves L-dopa-induced dyskinesia but worsens parkinsonism in MPTP monkeys.

OBJECTIVE: To determine whether dopamine (DA) D1 or DA D2 receptors are associated predominantly with the antiparkinsonian versus the dyskinetic effect of levodopa. METHODS: The authors used four L-dopa-primed, dyskinetic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-exposed monkeys to test whether acute and selective blockade of the DA D1 receptor subtype, using SCH 23390 and NNC 01-112, could reduce L-dopa-induced dyskinesias without altering the relief of symptoms. Blockade of DA receptors using sulpiride (D2) and clozapine (D1-D2-like) was studied for comparison. RESULTS: With the notable exception of the lowest dose of clozapine tested, coadministration of DA D1 or D2 antidopaminergic agents with L-dopa reduced the L-dopa-induced dyskinesias but also caused a return of parkinsonian disability. Prolonged latencies from intake of a single oral dose of L-dopa to turning "on," decreased duration of the "on" state, and a complete failure to induce benefit was also observed. CONCLUSION: Low-dose clozapine could be an effective adjunct to reduce L-dopa-induced dyskinesias without altering the relief of parkinsonian symptoms. Interactions with many neurotransmitter systems may explain the better pharmacologic profile of clozapine, including DA D4 (rather than D1), serotonin, acetylcholine, and noradrenaline. Neither dyskinesias nor antiparkinsonian effects can be ascribed solely to the D2 or D1 receptor. Thus, some cooperation between the two receptors appears necessary for these behavioral effects.

Antiparkinsonian effect of a new selective adenosine A2A receptor antagonist in MPTP-treated monkeys.

BACKGROUND: Chronic treatment with L-3,4-dihydroxyphenylalanine (L-dopa) is often associated with motor side effects in PD patients. The search for new therapeutic approaches has led to study the role of other neuromodulators including adenosine. Among the four adenosine receptors characterized so far, the A2A subtype is distinctively present on striatopallidal output neurons containing enkephalin and mainly bearing dopamine (DA) D2 receptors (indirect pathway). Studies in DA-denervated rats suggest that blockade of adenosine A2A receptors might be used in PD. OBJECTIVE: To evaluate the antiparkinsonian effect of a new selective adenosine A2A receptor antagonist, KW-6002, in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys. METHODS: In the present study, we used six MPTP-exposed cynomolgus monkeys already primed and exhibiting L-dopa-induced dyskinesias to evaluate both the antiparkinsonian and dyskinetic effect upon challenge with two oral doses (60 and 90 mg/kg) of KW-6002 administered alone or in combination with L-dopa/benserazide (50/12.5 mg). RESULTS: KW-6002 administered alone produced a dose-dependent antiparkinsonian response that reached the level of efficacy of L-dopa/benserazide but was less likely to reproduce dyskinesias in these animals. When co-administered, KW-6002 potentiated the effects of L-dopa/benserazide on motor activity (up to 30%) without affecting the dyskinetic response. CONCLUSION: Adenosine A2A receptor antagonists have antiparkinsonian effects of their own with a reduced propensity to elicit dyskinesias. They might therefore be useful agents in the treatment of PD.

Basaloid squamous cell carcinoma: a distinctive human papilloma virus-related penile neoplasm: a report of 20 cases.

Most penile neoplasms are squamous cell carcinomas (SCC), but there are subtypes that show morphologic and possibly etiologic differences. Clinicopathologic features of 20 patients with basaloid carcinoma (BC), an unusual variant of squamous cell carcinoma, are presented. Median age was 52 years, and all tumors were located in the glans, three confined to the perimeatal region. Average tumor size was 3.8 cm. Microscopically, nests of small, basophilic cells with numerous mitosis were present. Human papillomavirus DNA sequences (type 16), using the polymerase chain reaction (PCR), were found in 9 of 11 cases. Differential diagnosis included urethral transitional cell, basal cell, small cell neuroendocrine, and metastatic carcinoma. Factors more significantly associated with regional metastasis and mortality were tumor thickness greater than 10 mm and infiltration of the corpus cavernosum. A comparison with typical squamous cell carcinoma showed basaloid carcinoma to have a higher histologic grade, a deeper invasion of penile anatomic levels, and a higher mortality rate. Of 17 patients observed, 10 were dead of disease (average time, 34 months), one was alive with disease 6 months after diagnosis, and 5 were alive and free of disease (average time, 71 months); the remaining patient died of other causes. Basaloid carcinoma is a distinctive morphologic subtype of squamous cell carcinoma frequently associated with the human papilloma virus.

Mesencephalic grafts partially restore normal nigral dynorphin levels in 6-hydroxydopamine-lesioned rats treated chronically with L-dihydroxyphenylalanine.

An increase of dynorphin levels is commonly observed in the substantia nigra of 6-hydroxydopamine-lesioned rats chronically treated with daily injections of L-DOPA. This study investigates the potential of fetal mesencephalic grafts to restore normal levels of dynorphin in such cases. After 19 consecutive days of treatment with L-DOPA, lesioned rats with the most severe nigral cell loss showed increased levels of dynorphin in the substantia nigra ipsilateral to the lesion, as expected. The changes were assessed by standard immunohistochemical techniques combined with the use of an image analysis system. Such changes were not observed in the substantia nigra of rats that received fetal mesencephalic cells in the striatum six months prior to the beginning of the chronic treatment. However, only animals displaying heavy loss of dopaminergic neurons in the substantia nigra pars compacta showed significant changes of dynorphin levels in the substantia nigra following drug treatment. Our results show that fetal nigral cells transplanted into the striatum have the potential to prevent biochemical changes observed in the basal ganglia induced by the lesion of the nigrostriatal pathway and chronic treatment with L-DOPA. It is still hypothesized from studies in rodents that this peptide may play a role in the appearance of DOPA-induced dyskinesia, because dynorphin levels increase in the substantia nigra pars reticulata after L-DOPA treatment. If this happens to be the case, then the use of fetal nigral grafts could therefore be an important step to prevent the induction of dyskinesia after chronic L-DOPA treatment.

Correlation of functional recovery after a 6-hydroxydopamine lesion with survival of grafted fetal neurons and release of dopamine in the striatum of the rat.

Female rats were lesioned with 6-hydroxydopamine in the left substantia nigra. At least two weeks later they were tested with amphetamine (5 mg/kg, s.c.) and apomorphine (0.25 mg/kg, s.c.). A cell suspension from the ventral mesencephalon of rat embryos was distributed in three sites in a triangular fashion in the center of the denervated striatum. The amphetamine test was then repeated every month for six months. The pattern of circling to amphetamine before the graft was strictly ipsiversive in all animals. From the first month we observed a progressive change and three patterns of rotation could be observed. In 21% of animals, the total number of ipsiversive turns in 90 min actually increased but during the first 20 min the animals turned contralaterally to the lesion (and to the graft). In 38% of animals, the total number of turns switched from ipsiversive to contraversive with the animals turning initially toward the intact side and during the second half of the test toward the lesion. Finally 41% of rats progressively switched to turning only toward the intact side. In all cases, maximal contraversive turning occurred during the initial 20 min. In these rats, tyrosine hydroxylase-positive cells were detected mainly in the dorsal striatum with a few in the central portion. Moreover there was a strong correlation between the number of surviving grafted neurons and the growth of their fiber into the host striatum and the extent of recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Nonrandom chromosomal imbalances in human ovarian surface epithelial cells immortalized by HPV16-E6E7 viral oncogenes.

We had previously immortalized human ovarian surface epithelial (HOSE) cells using HPV16E6E7 ORFs. In order to identify crucial genetic events involved during cell immortalization, the genomic profile of immortalization of five HOSE cell lines was analyzed by comparative genomic hybridization. Our results showed that chromosomal imbalance was common in HOSE cells after immortalization. The common chromosomal imbalances identified in immortal HOSE cells are: +19q13.1 (5/5 lines), -13q12 approximately qter (4/5 lines), +5q15 approximately q33 (3/5 lines), +20q11.2 approximately q13.2 (3/5 lines) and -22q11.2 approximately qter (3/5 lines). Other chromosomal imbalances, which were detected in two of the five immortal HOSE cell lines, included gains on chromosome 1 and 11q12 approximately q13, and losses on 2p, 4q, 8p, 10p and 11q14 approximately qter. The chromosomal imbalances observed in HOSE cells before immortalization include -8pter approximately p11.2, -11q23 approximately qter, -13q12 approximately qter and +19 which may represent early genetic events during cell immortalization. The genomic profile was examined in one HOSE cell line (HOSE 6-3) at various stages of immortalization. The genomic profiles of HOSE 6-3 cells after crisis were largely stable. A few additional chromosomal imbalances were detected in the immortalized HOSE cells after an extensive culture period including +11pter approximately q23, -15q23 approximately qter, and +17q12 approximately qter. Identification of nonrandom chromosomal imbalance in immortalized HOSE cells may facilitate the identification of specific chromosomes harboring genes involved in the immortalization of human ovarian surface epithelial cells.

5-HT1 receptors mediating contraction in bovine cerebral arteries: a model for human cerebrovascular '5-HT1D beta' receptors.

We report on the pharmacological profile of the 5-HT receptor which induces contraction of the bovine isolated cerebral arteries. Several 5-HT receptor agonists were tested for their ability to induce vasoconstriction in bovine pial arteries and their potencies were compared to that of 5-HT. The rank order of agonist potency can be summarized as 5-carboxamidotryptamine (5-CT) = RU 24969 > or = 5-HT > sumatriptan > alpha-methyl-5-HT > methysergide > 2-methyl-5-HT > ((+-)-2-dipropylamino-8-hydroxy-1,2,3,4-tetrahydronaphthalene (8-OH-DPAT). Only methysergide induced a contraction which was smaller than that elicited by 5-HT. Antagonists with selective affinity at 5-HT1A/1B (propranolol), 5-HT1C (mesulergine), 5-HT2 (ketanserin, mianserin) and 5-HT3 (MDL 72222) sites were inactive to block the 5-HT-induced contraction. In contrast, the 5-HT1/5-HT2 receptor antagonists methiothepin and metergoline inhibited the 5-HT-induced response with relatively high affinity (pA2 = 8.16 +/- 0.26 and 6.73 +/- 0.05, respectively). Overall, this pharmacological profile indicated clearly that a 5-HT1 receptor, most closely related to the 5-HT1D subtype, is responsible for the 5-HT-induced contraction of bovine cerebral arteries. Correlation analysis of the potencies of a series of 5-HT receptor agonists and antagonists in bovine and human cerebrovascular preparations showed a highly significant positive correlation (r = 0.94, P = 0.0051).(ABSTRACT TRUNCATED AT 250 WORDS)

Antidyskinetic effect of JL-18, a clozapine analog, in parkinsonian monkeys.

Clozapine reduces L-3,4-dihydroxyphenylalanine (L-Dopa)-induced dyskinesias in parkinsonian patients. To test if the antidyskinetic effect of clozapine is related to antagonism at the dopamine D(4) receptor, we investigated the effect of 8-methyl-6-(4-methyl-1-piperazinyl)-11H-pyrido[2,3-b][1, 4]benzodiazepine (JL-18), a structural analog of clozapine which is more selective for this receptor. Four 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP)-treated cynomolgus monkeys with a stable parkinsonian syndrome and reproducible dyskinesias to L-Dopa were used in this study. They were injected subcutaneously (s.c.) with L-Dopa methyl ester (125 mg per animal) plus benserazide (50 mg per animal; L-Dopa/benserazide) alone or in combination with JL-18 (at the doses of 0.1, 0.3, or 0.9 mg/kg, s.c.). Subcutaneous injection of sterile saline was used as control. L-Dopa/benserazide increased locomotion and improved parkinsonism but also induced dyskinesias. Co-administration of JL-18, at low doses (0.1, 0.3 mg/kg) with L-Dopa/benserazide, produced a dose-dependent reduction in L-Dopa-induced dyskinesias without a parallel return to parkinsonism. The present results suggest that novel selective dopamine D(4) receptor antagonists may represent a useful tool to reduce L-Dopa-induced dyskinesias.

Effects of acute and repeated treatment with a novel dopamine D2 receptor ligand on L-DOPA-induced dyskinesias in MPTP monkeys.

(S)-(-)-3-(3-(methylsulfonyl)phenyl)-1-propylpiperidine ((-)-OSU6162) is a phenylpiperidine derivative which exhibits low affinity to the dopamine D2 receptor in vitro. However, in vivo, positron emission tomography scanning studies show that the compound displaces the selective dopamine D2 receptor antagonist, raclopride. We have evaluated, in this study, the effect of (-)-OSU6162, on L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesias in a primate model of Parkinson's disease. Five 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated cynomolgus monkeys with a stable parkinsonian syndrome and reproducible dyskinesias to L-DOPA were used in this study. The monkeys were housed in observation cages equipped with an electronic motility monitoring system. They were injected subcutaneously (s.c.) with L-DOPA methyl ester (125 mg per animal) plus benserazide (50 mg per animal; L-DOPA/benserazide) alone or in combination with (-)-OSU6162 (1.0, 3.0, 6.0 or 10 mg/kg, s.c.). Subcutaneous injection of sterile saline was used as control. L-DOPA/benserazide increased locomotion and improved parkinsonism but also induced dyskinesias. Co-administration of (-)-OSU6162 with L-DOPA/benserazide produced a significant reduction in L-DOPA-induced dyskinesias. This improvement in L-DOPA-induced dyskinesias occurred mainly at the onset of the L-DOPA/benserazide effect as reflected by an increase in the duration of the "ON" state without dyskinesias up to 3.4 fold after (-)-OSU6162 co-administration as compared to L-DOPA/benserazide alone. The anti-dyskinetic effect of (-)-OSU6162 was maintained during 14 days and no tolerance to this effect was observed. Our data suggests that (-)-OSU6162 could be of significant clinical value to reduce L-DOPA-induced dyskinesias in fluctuating advanced Parkinson's disease patients.

Sustained cabergoline treatment reverses levodopa-induced dyskinesias in parkinsonian monkeys.

The pathophysiology of L-Dopa-induced dyskinesias (LID), a common problem after long-term use of L-dopa in the treatment of Parkinson's disease (PD), is not completely understood. Oscillations in L-Dopa concentrations in the brain are believed to be responsible, at least in part, for their pathogenesis. This study was aimed at verifying whether chronic administration of cabergoline, a long-acting dopamine D2-like receptor agonist, can reverse established LID. Four MPTP-treated cynomolgus monkeys with long-standing and stable parkinsonian syndrome and reproducible dyskinesias to L-Dopa, were used in this study. We compared the antiparkinsonian and dyskinetic responses of L-Dopa methyl ester (62.5 mg and 125 mg), given with benserazide (50 mg) (L-Dopa/benserazide), administered before and after a 6-week period during which the animals were treated only by daily administration of cabergoline (doses ranging from 0.125 to 0.185 mg/kg, subcutaneous). During cabergoline treatment, the monkeys initially showed marked dyskinesias, which were reduced significantly after 4 weeks of treatment. However, there was no tolerance to its antiparkinsonian effect. L-Dopa/benserazide given 4 days after cabergoline withdrawal produced a significant antiparkinsonian effect, but dyskinesias were dramatically reduced compared to what had been seen before chronic cabergoline treatment. The duration of the L-Dopa response was not increased after chronic administration of cabergoline. Our data suggest that sustained dopamine D2 receptor stimulation could be of value when trying to reduce or to reverse LID in patients with fluctuating advanced PD.

Effect of the selective D1 antagonists SCH 23390 and NNC 01-0112 on the delay, duration, and improvement of behavioral responses to dopaminergic agents in MPTP-treated monkeys.

We assessed the antiparkinsonian response in MPTP-treated monkeys after acute or repeated treatment with oral L-Dopa, subcutaneous administration of L-Dopa methyl ester (LDME) or apomorphine, alone and in combination with D1 antagonists SCH 23390 (SCH) or NNC 01-0112 (NNC). When given alone, the L-Dopa effect occurred within the first hour after treatment. Coadministration of SCH or NNC with L-Dopa significantly delayed the onset of action. The response duration remained unchanged, as did the extent of the antiparkinsonian effect, after SCH, whereas the former became shorter at the higher doses of NNC tested. Bypass of the gastrointestinal tract using parenteral injections of LDME and apomorphine allowed the rapid turning "on" of the animals. Both D1 antagonists administered with LDME delayed the onset and shortened the duration of the therapeutic effect as the dose increased. Pretreatment with SCH failed to block the antiparkinsonian effect induced by apomorphine, but reduced the response duration markedly in a dose-related fashion. Repeated treatment of one monkey with SCH combined with the same dopaminergic drugs produced results similar to those obtained after acute treatment in four animals. The results obtained with parenteral administration of LDME and apomorphine most probably involve pharmacodynamic actions resulting in increased threshold of response. The delay observed with L-Dopa suggests pharmacokinetic interference possibly mediated via dopamine receptors located at the level of the gut.