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Biomedical subjects

J Chacón

Publications and source records attributed to J Chacón.

At least 19 recordsLinked to original sources
PubMed1999

Breeding soundness evaluation of extensively managed bulls in Costa Rica.

This paper describes the results of single breeding soundness evaluations (BSE) in 898 Bos indicus, Bos taurus and B. indicus x B. taurus bulls, 1 to 12 yr old, extensively reared in different climatic regions of Costa Rica and representing approximately 2% of the total breeding bull population. Thirty-three percent (n = 296) of the bulls were classified as unsound for breeding owing to clinical problems (9.1%, n = 82), low scrotal circumference (SC) being the most common finding, followed by unsatisfactory sperm morphology (23.9%, n = 214). The prevalence of bulls unsound for breeding was lowest in Bos indicus (29%, P < 0.01), intermediate in B. taurus (41%), and highest in B. indicus x B. taurus (48%). The percentages of abnormal sperm heads, acrosomes and midpieces tended to be higher in the ejaculates of bulls with softer testicular consistency (P < 0.001), a long scrotum (P < 0.01) or a low SC (P < 0.05), and such bulls were more often classified as being unsound for breeding (P < 0.05). Frequencies of sperm abnormalities were higher in bulls < 2 yr of age than in older males (P < 0.01) and were highest in B. indicus x B. taurus bulls (P < 0.001). The results confirm differences between species in their adaptability to a tropical environment and support earlier evidence of an association between SC, testicular consistency and scrotal length clinical parameters, and testicular function in bulls.

Animals↗
PubMed1997

Early combination of bromocriptine and levodopa in Parkinson's disease: a prospective randomized study of two parallel groups over a total follow-up period of 44 months including an initial 8-month double-blind stage.

To determine if the combination of levodopa (LD) plus bromocriptine (Br) in the early stages of Parkinson's disease (PD) permits reduction of LD dosage and consequently results in fewer motor fluctuations and dyskinesias, a double-blind, multicenter prospective study in 50 PD patients who had responded favorably to LD while under treatment with that drug for < or = 6 months was undertaken. Patients were randomized into two parallel groups (LD alone and LD plus Br). During the first placebo-controlled stage of the study lasting 8 months, association of a fixed dose of Br (15 mg/day) in the LD regimen did not allow a significant reduction in the daily LD dose. Still, in patients on combined LD plus Br, there was a tendency toward smaller daily requirements of LD as compared with those on LD alone, and the difference in LD dose between the two groups was significantly different (515.4 +/- 240 vs. 725.6 +/- 230 mg/day; p < 0.01) after 44 months of continuous treatment in the 40 patients still enrolled in the open-label stage. At that point in time, the mean dose of Br had been increased by 9.2 mg in the combined treatment group, and the mean dose of LD was 40.7% lower than in the group receiving LD alone. On subsequent evaluations, the number of patients with dyskinesias or describing wearing-off fluctuations severe enough to require changes in treatment was lower than in the group under combined therapy, the differences being significant after 20 and 44 months, respectively (36.8 vs. 9.5 and 47.3 vs. 14.2%). Our results support early combined LD-Br therapy in PD, but no conclusions can be drawn as to whether this dopamine agonist exerts a preventive effect on the late side effects of LD or has another mechanism of action.

Aged↗
PubMed1997

[The effect of controlled release of DOPA and carbidopa on clinical response and plasma pharmacokinetics of DOPA in parkinsonian patients].

This is a multicentric double blind comparison of the effects of standard and slow release levodopa + carbidopa formulations in patients with Parkinson's disease. Sixty four patients with simple fluctuations were included and 43 finished the study. The study had three phases: a) optimal dose findings phase with standard levodopa + carbidopa; b) open label, cross over study with the two formulations, and c) double blind, parallel investigation. The following results were obtained. There was not a difference in the severity of disability according to UPDRS, part 3, scores though the subjective impressions of patients were in favor of standard formulations. The Sustained release levodopa + carbidopa produced significant improvement of dystonia in off period, pain due to akinesia in off and the number of hours in off and the quality and latency of sleep. In addition there was a tendency in favor of slow release compounds for early morning akinesia, global effect and impression of the examining physician. Low protein diet improved the kinetics of levodopa and the clinical response with both formulations. The clinical usefulness of standard and slow release levodopa + carbidopa formulation should be weighted according to individual problems of patients with Parkinson's disease.

Age of Onset↗
PubMed1997

[Neuroborreliosis in a patient with progressive supranuclear paralysis. An association or the cause?].

INTRODUCTION: Many different neurological conditions may be seen in the later stages of Lyme's Disease, such as blindness, epileptic crises, CVA, extrapyramidal disorders, amyotrophic lateral sclerosis, and dementia may be yet another form of presentation of chronic infection due to Borrelia burgdorferi (Bb). Progressive Supranuclear Paralysis (PSP), a disorder of unknown aetiology, considered to be the commonest cause of Parkinsonism-plus, one of the symptoms of which is dementia, has never been mentioned in this type of differential diagnosis. CLINICAL CASE: We present the case of a 78 year old man with sub-acute mental deterioration, Bb positive serology in both plasma and CSF, and with clinical and epidemiological features compatible with Lyme's Disease. Complementary tests were negative. The syndrome corresponded to Lyme's Disease and improved after treatment with ceftriaxona. CONCLUSIONS: We consider aspects of the aetiology of PSP which are still not clear. In our patient, the aetiology seemed to be Bb infection, according to the criteria of the original description of the disease and in view of the neuropathological findings which have shown Bb in the substancia nigra of the mid-brain and the existence of an animal model in which Bb shows a particular tendency to colonize infratentorial structures.

Aged↗
PubMed1996

[Symptomatic chronic hemichorea of a vascular lesion in the contralateral putamen].

We present a case of chronic multifocal choreform dyskinesia with evident anatomical and temporal relationship with a contralateral putamen lesion of ischaemic origin after embolism originating in a partially thrombosed intracavernous caratid aneurysm. Isolated putamen lesions are associated with abnormal dystonic type involuntary movements, bilateral to Parkinsonisms, sometimes associating both these types of movements, and lesions involving the cauda giving rise to choreic movements. Given the rarity in the literature of this entity, chorea associated with unilateral ischaemic putamen lesion, and the absence of pathogenic mechanisms which might satisfactorily explain it, we propose a series of possibilities which could underlie this type of chorea. If putamen macroscopic lesions are really more associated with dystonic manifestations, it is possible that, in some cases they might selectively alter base ganglia circuits and bring on chronic choreas rather than dystonia.

Aged↗
PubMed1996

[Post-traumatic tics].

Secondary tics are those in which an aetiology justifying them can be found, as compared to idiopathic tics, which make up the majority, and the Gilles de la Tourette syndrome (SGT), which is, at the moment, of unknown origin. Of the possible aetiologies described as causing tics, craneo-encephalic trauma has been mentioned on very few occasions. We present a case of post-traumatic tics (verbal and neck) in a young man of 24, and review the published cases which can be considered to be of post-traumatic tics. We have found six cases of tics secondary to traumas, all craneo-encephalic, like ours (the one under study). The time interval between the blow and the appearance of the tic or tics varied between 2 weeks and 3 months. The absence of significant lesions seen in the complementary investigations make it impossible for us to discover the site of the lesion caused by the trauma. However, the presence in some cases of other tics before the trauma, and of family histories of tics, supports the idea of a genetic basis or predisposition to suffer this disorder.

Adult↗
PubMedDate not supplied

[Sotos syndrome associated with focal dystonia].

INTRODUCTION: Sotos syndrome is a form of infantile gigantism characterized by excessive body size from the time of birth, particular facies, acromegalic changes and signs of non-progressive cerebral involvement. The etiology is unknown. Diagnosis is based on somatometric data and the particular phenotype traits. Biochemical and endocrine studies are normal. Torticollis is a focal dystonia and therefore more common in adults. CLINICAL CASE: A 20 year old woman with macrosomic features since birth presented with: weight 104 kg, height 182 cm; prognathism, hypertelorism, a broad over hanging forehead with a high hair line; large ears, hands and feet; torticollis towards the right with elevation and anteroversion of the right shoulder which caused symptomatic scoliosis. She was bradypsychic and rather slow in speech. The complementary tests done (cerebral and cervical CT and MR, bone gammography, evoked potentials, EMG-ENG, sural nerve biopsy, biopsy of skin and muscle, EEG and hormone and biochemistry studies) were normal. The torticollis was treated with botulinus toxin and improved considerably, as did the scoliosis. CONCLUSIONS: To date, dystonia has not been described in association with Sotos syndrome. This may be a causal association, or even perhaps hereditary, since the patient's mother had dystonia (in the form of blepharospasm).

Adolescent↗
PubMedDate not supplied

[Parkinson disease of juvenile onset with systemic lupus erythematosus in a pre-symptomatic stage].

INTRODUCTION: Parkinson's disease of juvenile onset is known to be rarely seen in clinical neurology. Occasionally it may be secondary to other pathological processes which have to be excluded by investigation of such cases, since the clinical, therapeutic and prognostic significance varies considerably depending on whether the condition is idiopathic or secondary. CLINICAL CASE: We present the case of a patient whose illness started when she was 16 years old. She complained of rigidity, tremor and akinesia. Her condition was studied to find whether the syndrome was secondary. Thus, on four occasions, at annual visits during a period of five years, immunological changes suggestive of systemic lupus erythematous were observed. Neuroimaging, magnetic resonance and computerized axial tomography studies were completely normal on all four occasions over the five years during which the patient had annual follow-up reviews. CONCLUSION: We considered whether the rigidity-akinesia-tremor syndrome might have been secondary to systemic lupus erythematous, due to a probable pathological focus of cerebral vasculitis, in this clinical case which we report.

Adolescent↗
PubMedDate not supplied

[Intrathecal perfusion pump with baclofen in generalized dystonia].

OBJECTIVES: We show the effectiveness of treatment with continuous intrathecal baclofen infusion in a case of hereditary generalized dystonia refractory to anticholinergics, tetrabenazine, pimozide, L-dopa, benzodiazepines and thalamotomy. CLINICAL CASE: A 26 years old female patient, when she was 11 years old began with torsion dystonia in her left feet, that progressively worsened to involve her entire body. She had painful spasms. She had four brothers, three of them with dystonia and one healthy. Her uncle grandfather had similar symptoms. Complementary explorations to reject secondary origin was negatives. She was treated with high and progressive dosages of anticholinergics, pimozide, tetrabenazine, benzodiazepines, L-dopa and thalamotomy without improvement. Underwent intrathecal baclofen test dosing, we used 25, 50, 100 micrograms/day, the last one with improvement during 10 hours. A pump was inserted with an initial dose of 220 micrograms/day. After pump insertion, baclofen dosage was gradually increased to 450 micrograms/day. She had a great improvement in right part of her body and less in her left body. Painful spasms had disappeared. CONCLUSION: We propose continuous baclofen intrathecal infusion pump for patients with severe torsion dystonia that not response to ordinal treatment.

Adult↗