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Biomedical subjects

J L Castillo

Publications and source records attributed to J L Castillo.

At least 19 recordsLinked to original sources

Evaluation of fluoride release from commercially available fluoride varnishes.

BACKGROUND: The authors conducted a study to evaluate the fluoride released from two fluoride varnishes: Duraphat (Colgate-Palmolive Co., New York) and Duraflor (Pharmascience Inc., Montreal). Fluoride-release information for these commercially available dental products has not been available to clinicians treating children at risk of developing dental caries. METHODS: The authors painted enamel slabs from primary molar teeth with 30 milligrams of two varnishes: nine samples received Duraphat, nine received Duraflor and five samples served as controls. The samples were immersed in buffered calcium phosphate solution (pH, 6.0) to simulate the oral environment, and the amount of fluoride released was measured weekly for six months. RESULTS: From week 4 to the end of the study, Duraphat released significantly more fluoride than Duraflor. Duraflor continued releasing fluoride until week 19, while Duraphat released fluoride until week 28. The authors found greater variability in the release of fluoride from the Duraflor samples than from the Duraphat samples. Two-thirds of the fluoride was released from both products by the end of the study. CONCLUSIONS: Both varnishes released fluoride for five to six months. However, the two products exhibited differences in their release kinetics. CLINICAL IMPLICATIONS: These findings show that either of the fluoride varnishes may maintain a high level of fluoride in plaque fluid around primary teeth over a long period, but that the availability of fluoride may vary among tubes of the same product and between the two products themselves.

Biological Availability↗

[Restless legs syndrome: a clinical study in adult general population and in uremic patients].

BACKGROUND: The restless legs syndrome (RLS) is a movement disorder characterized by an imperative urge to move the legs, associated with paraesthesias, motor restlessness and worsening of symptoms at night with at least partial relief by activity. Its prevalence ranges between 2-15% of general adult population and 20-30% of uremic patients. AIM: To evaluate the frequency and the clinical features of RLS in a sample of general adult population and in uremic patients, in Chile, correlating it with biochemical parameters. METHOD: 100 relatives of outpatients and 166 uremic patients undergoing chronic haemodialysis were interviewed assessing the presence and severity of RLS according to current diagnostic criteria. Biochemical parameters assessed were hematocrit, serum ferritin, phosphate, intact parathyroid hormone (iPTH) levels. RESULTS: 13% of the general population sample was affected, 15% of them were severe. Forty three cases were found among uremic patients (25.9%) (p < 0.01 vs general population), 60% of them were severe and women were affected with higher frequency (p < 0.05) and severity (p < 0.01). Four patients presented RLS even during hemodialysis. No correlation was found with biochemical parameters. Most RLS cases had not been diagnosed previously. CONCLUSIONS: In our population RLS is common and undetected. It is especially prevalent and severe in uremic patients: we found no evidence that anaemia, iron deficiency or iPTH level play a major pathogenic role. Our findings emphasize the need of greater medical awareness of RLS because available therapy may improve the quality of life.

Adolescent↗

[HTLV-I seronegative idiopathic progressive spastic paraparesis: clinical and neurophysiological study of the sensory features].

BACKGROUND: HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a defined entity. However, there are many patients not well characterized with a similar clinical picture who are HTLV-I seronegative. OBJECTIVE: Clinical and neurophysiological description of patients with HTLV-I seronegative idiopathic paraparesis. PATIENTS AND METHODS: Seventeen patients (4 women and 13 men aged 24-67 years, average 52.3) were evaluated including clinical assessment, vibratory sensory analysis, quantitative somatosensory thermotest (QST), somatosensory evoked potentials (SSEPs), electromyography (EMG) and motor and sensory nerve conductions. RESULTS: In addition to the spastic paraparesis, 3 (17.6%) patients had pseudobulbar symptoms. Ten (58.8%) patients had a spastic gait but could walk unaided, 6 (35.2%) needed support and 1 patient could not walk. Bladder dysfunction was found in 10 (58.8) patients and sensory symptoms in 7 (41.1%). There was mild distal impairment of vibration and position sense, distal tactile and pinprick hypoesthesia in 4 (23.4%) patients. Tibial SSEPs were abnormal in 11 (64.7%). Nerve conduction studies and EMG were normal. QST showed cold hypoesthesia in 14 (82.4%) patients. Warm sensation and beat pain appeared unimpaired. CONCLUSIONS: All sensory abnormalities found were restricted to sensations carried by myelinated (A beta and A delta) channels. Sensory and motor abnormalities are similar to HAM/TSP patients suggesting a common pathogenesis.

Adult↗

Droplet vaporization at critical conditions: long-time convective-diffusive profiles along the critical isobar.

The heating of a cold fluid package introduced, at critical conditions, in a hotter environment of the same fluid at the critical pressure is analyzed. Critical anomalies of the fluid transport properties as well as an arbitrary equation of state are taken into account. In unconfined microgravity conditions and for times much longer than the characteristic acoustic time, the heat transfer becomes a convective-diffusive isobaric transient process. An asymptotic theory valid in the limit of very small ratio between the fluid densities in the hot and cold regions is developed. The divergency of the thermal conductivity kappa at the critical temperature controls the heat transfer to the cold region. In the present model it is shown that there exists a well defined border, denoted by R(t), delimiting two distinguishable regions. The outer region extends from the far field down to R(t) where the critical temperature T(c) is reached. There, the temperature gradient vanishes due to the divergency of kappa. Thus, heat does not penetrate in the inner cold region where the temperature remains equal to T(c). The heating of the initially cold fluid package takes place by the recession of the border R(t). The model predicts a temperature profile in the outer region which is quasisteady in a reference system receding with R(t). It is shown that R2(t) decreases linearly with time. The recession velocity and thus the vaporization time are obtained as a function of the geometry and of the far-field conditions. Furthermore, the restrictions imposed by the long-time isobaric hypothesis are analyzed.

Journal Article↗

Sensory dysfunction in HTLV-I-associated myelopathy/tropical spastic paraparesis. A comprehensive neurophysiological study.

We performed a comprehensive clinical and neurophysiological evaluation of function of the large- and small-caliber afferent pathways in 29 patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Sensory symptoms, particularly cutaneous paresthesias, were present in 11 (37.9%) patients. On examination, a mild distal impairment of vibration and sense of position were found in 14 (48.2%) and 5 (17.2%) patients, respectively. Ten (34.4%) patients had distal tactile hypoesthesia and 7 (24.1%) presented pinprick hypoesthesia. Quantitative somatosensory thermotest showed cold hypoesthesia in 58.6% of patients. Nerve conduction studies and electromyography were normal. Tibial somatosensory evoked potentials were abnormal in 88.5% of patients. All of the sensory abnormalities found were restricted to sensations carried by myelinated (A-beta and A-delta) fibers. Unmyelinated C fibers mediating warm sensation and thermal pain appeared unimpaired. Our findings indicate that the sensory dysfunction in HAM/TSP patients is probably due to a lesion restricted to the central nervous system.

Adult↗

[Chorea induced by oral contraceptives. Report of two cases].

We report two women using oral contraceptives, aged 17 and 33 years old, who presented with hemichorea. In both patients all other possible causes of chorea were discarded and the disease disappeared when contraceptives were discontinued. Four months later, the 33 years old patient used again oral contraceptives and chorea reappeared. This rare complication of contraceptive use has been previously reported in young and mainly nulliparous women.

Adolescent↗

[Factors that affect DNA content analysis by flow cytometry].

DNA ploidy and cell cycle analysis by flow cytometry is used to obtain additional information about the diagnosis and prognosis of different types of cancer. However, there are several disagreements among authors about the tissue source (fresh-frozen or paraffin embedded), cellular dissociation methods (mechanical, enzymatic or other), use of different dyes, lasers, analysis software with different mathematical models and interpretation of results. A discussion about the different aspects that affect the study of DNA ploidy and cell cycle and a consensus in publications is mandatory. A strict control of analysis processes and data interpretation is also necessary.

Cell Cycle↗

[Angina caused by subclavian-coronary steal in patients revascularized with internal mammary artery].

After coronary bypass surgery in the left internal mammary artery, occlusive atherosclerosis in the proximal subclavian artery can produce reverse flow in the mammary artery and myocardial ischemia (coronary-subclavian steal syndrome). This is a rare cause of recurrent myocardial ischemia. We present two patients with postoperative complete obstruction in the proximal subclavian artery and inverse flow in the mammary artery producing severe ischemia in the left anterior descending artery territory. Both patients were treated with subclavian-subclavian bypass, which in one patient was ineffective in producing an adequate anterograde flow in the left internal mammary artery. We review clinical management, diagnostic methods and therapeutic options used in the coronary-subclavian steal syndrome.

Aged↗

[Pulsatile tinnitus associated with a high jugular bulb and slow venous blood flow].

A case of permanent pulsatile tinnitus of the left ear in a patient with hypertriglyceridemia is reported. The combined radiological study with computed tomography, magnetic resonance imaging, and digital angiography excluded a glomus tumor and revealed an enlarged, high-position jugular bulb with slow blood flow. Causes of pulsatile tinnitus are discussed. We conclude that imaging techniques play a major role in the diagnosis of head and neck vascular abnormalities.

Arteriovenous Malformations↗

[Somatosensory evoked potentials and symptomatic response to dopaminergic drugs in Parkinson's disease].

Short latency somatosensory evoked potentials were measured in 10 patients with Parkinson's disease before and after the administration of Apomorphine 5 mg sc. Eight of these subjects were reassessed after one month of treatment with Levo-Dopa. These potentials were measured in other nine subjects before and after one month of treatment with Selegiline 10 mg od. There was a significant increase of frontal potential N30 in nine of 10 subjects that received apomorphine, in seven of eight patients treated with Levo-dopa and seven of nine patients treated with Selegiline. No changes in N20 parietal potential were observed. During apomorphine test, changes in N30 potential preceded clinical improvement in six patients and occurred simultaneously in three patients. No changes with apomorphine in N30 potential were observed in two healthy males. There was no relationship between electrophysiological changes and duration of disease or motor fluctuations. It is concluded that short latency somatosensory evoked potentials are an objective means of measuring dopaminergic response in patients with Parkinson's disease.

Adult↗

[Effect of the Nucleus CMP forte in 46 patients with progressive spastic paraparesis. Randomized and blind study].

BACKGROUND: Idiopatic or HTLV-1 associated progressive spastic paraparesis does not have a clear etiology or treatment. AIM: To assess the effects of a medication containing cytidinmonophosphate, uridintriphosphate and vitamin B 12 in the treatment of progressive spastic. PATIENTS AND METHODS: Patients with the disease were randomly assigned to receive the Nucleus CMP forte (containing dysodic cytidinmonophosphate 5 mg, trisodic uridintriphosphate 3 mg and hydroxicobalamin 2 Mg) tid or placebo during six months. Gait, spasticity, degree of neurogenic bladder and somatosensitive evoked potentials were assessed during treatment. RESULTS: Forty six patients aged 25 to 79 years old were studied, 24 were female and 29 HTLV-1 positive. Twenty two were treated with the drug and the rest with placebo. Gait and spasticity improved in 7 of 22 patients receiving the drug and 1 of 24 receiving placebo (p < 0.05). Neurogenic bladder improved in 10 of 22 receiving the drug and 4 of 24 receiving placebo (NS) Somatosensitive evoked potentials improved in four of seven patients treated with the drug and in two of seven treated with placebo. CONCLUSIONS: The medication caused a modest improvement in patients with progressive spastic paraparesis and was free of side effects.

Adult↗

Participation of ACTH1-10 and ACTH4-10 on the melatonin modulation of benzodiazepine receptors in rat cerebral cortex.

In this study, we examined the effect of intracerebroventricular (i.c.v) injection of melatonin and/or ACTH1-10 and ACTH4-10 on [3H]flunitrazepam binding sites in the cerebral cortex of hypophysectomized rats. Hypophysectomy increased the Bmax (maximum number of binding sites) of benzodiazepine (BNZ) receptors for at least 7 days after surgery, without changing KD (dissociation constant). The i.c.v. injection of melatonin to hypophysectomized rats significantly increased Bmax, whereas the same doses of melatonin were ineffective in sham-operated animals. In both cases, KD values were unchanged. The i.c.v. injection of ACTH1-10 to hypophysectomized animals significantly increased Bmax, an effect that was enhanced by simultaneous i.c.v. injection of ACTH1-10 + melatonin, reaching higher values of Bmax than the i.c.v. injection of these hormones individually. No significant changes in KD values were found after ACTH1-10 and/or melatonin administration. However, the i.c.v. injection of ACTH4-10 to hypophysectomized rats did not change Bmax, although it significantly increased KD values, indicating a decrease in the BNZ binding affinity. Melatonin injection counteracted this effect of ACTH4-10, returning KD to the control value. Moreover, although the lower dose of i.c.v. melatonin used, 10 ng, was unable to modify Bmax of BNZ binding in the ACTH4-10-injected group, the higher dose, 20 ng, significantly increased Bmax. The results suggest that these ACTH-derived peptides can modulate the effect of melatonin on brain benzodiazepine receptors.

Adrenocorticotropic Hormone↗

Chronic dacryosialadenitis in HTLV I associated myelopathy.

A prospective study was carried out on 48 patients with HTLV I associated myelopathy/tropical spastic paraparesis (HAM/TSP) to assess the association between this entity and Sjögren's syndrome. Fourteen patients (29.1%) had chronic dacryosialadenitis confirmed by a positive Schirmer's test and salivary gland biopsy. None of these patients had evidence of collagen disease and tests for Ro, La, and rheumatoid factor were negative except in one case. Therefore, the dacryosialadenitis could not be classified as either primary or secondary Sjögren's syndrome. Ten of the 14 patients (71.4%) had other systems (haematological, articular, dermatological, or respiratory) involved apart from the neurological and exocrine gland pathology. The findings suggest that the dacryosialadenitis associated with HTLV I is a disease of viral origin distinct from Sjögren's syndrome.

Adult↗

HTLV-I positive progressive spastic paraparesis (TSP) associated with a lymphoid disorder in three Chilean patients.

We describe the clinical and laboratory features in three Caucasian Chilean patients with tropical spastic paraparesis (TSP) associated with/or preceded by a lymphoproliferative disorder involving cutaneous lesions and localised lymphadenopathy. The neurological symptoms and signs were characteristic of TSP and CSF examination revealed the presence of oligoclonal bands. All three patients had a moderate leucocytosis (10-14 x 10(9)/l) with eosinophilia and a minority (2-4%) of circulating atypical polylobed or ATLL-like lymphocytes. Lymph node histology showed a diffuse pattern of infiltration (1 case) and marked expansion of the paracortical zone with convoluted lymphocytes and immunoblasts (2 cases). Skin biopsy demonstrated a dermal lymphoid infiltration with epidermotropism. Antibodies to HTLV-I were detected in the serum and CSF in the three patients and Southern blot analysis of peripheral blood mononuclear cells showed a monoclonal integration of HTLV-I proviral DNA in one case whereas in the two others the pattern was indicative of low level polyclonal integration. All three patients were treated with prednisolone and one with PUVA with transient partial response on the skin and neurological manifestations. Two patients died months to 5 years from presentation and the other is alive 12 years from diagnosis with active neurological and skin disease. The simultaneous occurrence of HTLV-I associated TSP with smouldering ATLL and a cutaneous ATLL or pre-leukaemic form is discussed.

Adult↗

Influence of the behaviorally active peptides ACTH1-10 and ACTH4-10 on the melatonin modulation of 3H-flunitrazepam receptor binding in the rat cerebral cortex.

Possible interactions of ACTH-like peptides with melatonin regulation of central-type benzodiazepine (BNZ) receptors have been studied by means of high-affinity 3H-flunitrazepam binding to rat cerebral cortex membrane preparations. Intracerebroventricular injections of melatonin produce a dose-dependent increase in Bmax in pinealectomized rats, without changes in KD. Analogous effects were obtained after intracerebroventricular injection of melatonin in adrenalectomized and in adrenalectomized plus pinealectomized rats, which indicated the lack of participation of adrenal steroids in this response. Moreover, intracerebroventricular injection of ACTH1-10 induced a similar dose-dependent increased Bmax in sham-operated animals, whereas pinealectomy, but not adrenalectomy, partially counteracted this effect of ACTH1-10 administration. Besides, simultaneous injection of ACTh1-10 plus melatonin reverses the effects of pinealectomy, resulting in an additive effect of both compounds on Bmax. The response obtained when using ACTh4-10 was somewhat different, because no dose response was obtained in any experiment. Although lack of endogenous melatonin partially reduced the increasing effect of ACTH4-10 on Bmax, there were no additive effects at the different doses used. The results strongly suggest that ACTH-like peptides, in addition to melatonin, play a role in regulating central-type rat BNZ receptors.

Adrenalectomy↗

[Dissection of vertebral artery: report of a case and review of the literature].

Vertebral artery dissection seems to be a frequent cause of stroke in young adults. We report a 34 years old female that suffered a cardiac arrest while practicing aerobics, with complete recovery and four months later developed an acute Wallenberg's syndrome. Magnetic resonance imaging showed an infarction in the right posterolateral medulla oblongata and in the right cerebellar hemisphere. Angiography revealed an occlusion of the third segment (V3) of the right vertebral artery which was hypoplastic. The patient was anticoagulated with a favorable clinical outcome. A follow up angiography, performed six months later, showed an incomplete recanalization of the vessel. Vertebral artery dissection should be suspected in every patient with ischemic symptoms or signs related to the vertebrobasilar territory, specially in young or middle aged patients with a history of trauma. Magnetic resonance imaging and ultrasound-doppler examinations are the diagnostic test of choice.

Adult↗

Melatonin counteracts pinealectomy-dependent decreases in rat brain [3H]flunitrazepam binding through an opioid mechanism.

The effect of intracerebroventricular (i.c.v.) injection of melatonin and/or beta-endorphin on the [3H]flunitrazepam binding sites in the cerebral cortex of pinealectomized or superior cervical ganglionectomized rats was studied. Pinealectomy decreased the maximum concentration of benzodiazepine receptors (Bmax) without affecting the dissociation constant (KD), while melatonin, ineffective in control animals, counteracted the effect of pinealectomy. Intracerebroventricular injection of beta-endorphin increases Bmax in both control and pinealectomized animals, the effect being significantly higher in the latter. Simultaneous i.c.v. injection of melatonin + beta-endorphin did not further increase Bmax in any group, whereas i.c.v. injection of naloxone significantly blocked the effects of melatonin and/or beta-endorphin administration. Pineal sympathetic denervation produced a significant increase in Bmax and KD, whereas i.c.v. injection of melatonin further increased the former, restoring KD to control values. Neither i.c.v. administration of beta-endorphin or melatonin + beta-endorphin significantly modified the ganglionectomy-dependent increase in Bmax, although both treatments restored KD to control values. Naloxone administration had no effect on beta-endorphin- and melatonin + beta-endorphin-treated ganglionectomized groups, but counteracted the increased effect of melatonin on Bmax in ganglionectomized animals.

Animals↗