Tratamento prévio com trilostano e levotiroxina em subdose dificultam diagnóstico de hipotireoidismo canino / Previous treatment with trilostane and levotiroxin in subdosis difficult the diagnosis of canine hypothyroidism

Background: hypothyroidism is a disease of clinical importance that causes multisystem disorders, which can be confused with other endocrinopathies. Rapid and accurate diagnosis is necessary in order to avoid worsening of the clinical manifestation. The use of drugs in a wrong way can directly imply the difficulty of the diagnostic approach, since they may cause changes in the biochemical profiles, which are of great importance as markers in diseases of animals with low thyroid function.Case: The case reports a German Spitz male, one year old and six months old, neutered, who presented bilateral do not cause itching alopecia, being treated by another professional for endocrine and fungal affections. In this same medical appointment were neglected biochemical and hematological profile exams. The exams that had been performed were skin scrapings, which showed growth of fungi and bacteria, besides the measurement of thyroid hormones as TSH, T4L (T4 free) e T3, and also the low-dose dexamethasone suppression test. Based on the findings the therapy instituted by such professional was the administration of itraconazole (ITL®), levothyroxine sodium (compounded drugs) and trilostane (compounded drugs). With absence of clinical improvement, the guardian came to the hospital veterinary, in search of a second diagnostic opinion, where during the collection of information at the time of the anamnesis the patient presented lethargy, drowsiness and absence of hair on both sides. During the clinical examination, the animal presented mild bradycardia and a slightly diminished rectal temperature; in the dermatological evaluation the presence of pup pelt, cutaneous hyperpigmentation and hair thinning in the abdominal area were noted. From this evaluation, hematological exams were requested, which had altered the presence of lymphocytosis, and biochemical tests, where changes in the cholesterol and triglyceride levels were expected, but they were within the normal range.[...]

Tratamento prévio com trilostano e levotiroxina em subdose dificultam diagnóstico de hipotireoidismo canino / Previous treatment with trilostane and levotiroxin in subdosis difficult the diagnosis of canine hypothyroidism

Background: hypothyroidism is a disease of clinical importance that causes multisystem disorders, which can be confused with other endocrinopathies. Rapid and accurate diagnosis is necessary in order to avoid worsening of the clinical manifestation. The use of drugs in a wrong way can directly imply the difficulty of the diagnostic approach, since they may cause changes in the biochemical profiles, which are of great importance as markers in diseases of animals with low thyroid function.Case: The case reports a German Spitz male, one year old and six months old, neutered, who presented bilateral do not cause itching alopecia, being treated by another professional for endocrine and fungal affections. In this same medical appointment were neglected biochemical and hematological profile exams. The exams that had been performed were skin scrapings, which showed growth of fungi and bacteria, besides the measurement of thyroid hormones as TSH, T4L (T4 free) e T3, and also the low-dose dexamethasone suppression test. Based on the findings the therapy instituted by such professional was the administration of itraconazole (ITL®), levothyroxine sodium (compounded drugs) and trilostane (compounded drugs). With absence of clinical improvement, the guardian came to the hospital veterinary, in search of a second diagnostic opinion, where during the collection of information at the time of the anamnesis the patient presented lethargy, drowsiness and absence of hair on both sides. During the clinical examination, the animal presented mild bradycardia and a slightly diminished rectal temperature; in the dermatological evaluation the presence of pup pelt, cutaneous hyperpigmentation and hair thinning in the abdominal area were noted. From this evaluation, hematological exams were requested, which had altered the presence of lymphocytosis, and biochemical tests, where changes in the cholesterol and triglyceride levels were expected, but they were within the normal range.[...](AU)

Evidence for the involvement of peripheral ß-adrenoceptors in delayed liquid gastric emptying induced by dipyrone, 4-aminoantipyrine, and antipyrine in rats.

Dipyrone (Dp), 4-aminoantipyrine (AA), and antipyrine (At) delay liquid gastric emptying (GE) in rats. We evaluated adrenergic participation in this phenomenon in a study in male Wistar rats (250-300 g) pretreated subcutaneously with guanethidine (GUA), 100 mg·kg-1·day-1, or vehicle (V) for 2 days before experimental treatments. Other groups of animals were pretreated intravenously (iv) 15 min before treatment with V, prazosin (PRA; 1 mg/kg), yohimbine (YOH; 3 mg/kg), or propranolol (PRO; 4 mg/kg), or with intracerebroventricular (icv) administration of 25 µg PRO or V. The groups were treated iv with saline or with 240 µmol/kg Dp, AA, or At. GE was determined 10 min later by measuring the percentage of gastric retention (%GR) of saline labeled with phenol red 10 min after gavage. %GR (mean ± SE, n=8) indicated that GUA abolished the effect of Dp (GUA vs V=31.7 ± 1.6 vs 47.1 ± 2.3%) and of At (33.2 ± 2.3 vs 54.7 ± 3.6%) on GE and significantly reduced the effect of AA (48.1 ± 3.2 vs 67.2 ± 3.1%). PRA and YOH did not modify the effect of the drugs. %GR (mean ± SE, n=8) indicated that iv, but not icv, PRO abolished the effect of Dp (PRO vs V=29.1 ± 1.7 vs 46.9 ± 2.7%) and At (30.5 ± 1.7 vs 49 ± 3.2%) and significantly reduced the effect of AA (48.4 ± 2.6 vs 59.5 ± 3.1%). These data suggest activation of peripheral ß-adrenoceptors in the delayed GE induced by phenylpyrazolone derivatives.

Evidence for the involvement of peripheral -adrenoceptors in delayed liquid gastric emptying induced by dipyrone, 4-aminoantipyrine, and antipyrine in rats

Dipyrone (Dp), 4-aminoantipyrine (AA), and antipyrine (At) delay liquid gastric emptying (GE) in rats. We evaluated adrenergic participation in this phenomenon in a study in male Wistar rats (250-300 g) pretreated subcutaneously with guanethidine (GUA), 100 mg·kg−1·day−1, or vehicle (V) for 2 days before experimental treatments. Other groups of animals were pretreated intravenously (iv) 15 min before treatment with V, prazosin (PRA; 1 mg/kg), yohimbine (YOH; 3 mg/kg), or propranolol (PRO; 4 mg/kg), or with intracerebroventricular (icv) administration of 25 µg PRO or V. The groups were treated iv with saline or with 240 µmol/kg Dp, AA, or At. GE was determined 10 min later by measuring the percentage of gastric retention (%GR) of saline labeled with phenol red 10 min after gavage. %GR (mean±SE, n=8) indicated that GUA abolished the effect of Dp (GUA vs V=31.7±1.6 vs 47.1±2.3%) and of At (33.2±2.3 vs 54.7±3.6%) on GE and significantly reduced the effect of AA (48.1±3.2 vs 67.2±3.1%). PRA and YOH did not modify the effect of the drugs. %GR (mean±SE, n=8) indicated that iv, but not icv, PRO abolished the effect of Dp (PRO vs V=29.1±1.7 vs 46.9±2.7%) and At (30.5±1.7 vs 49±3.2%) and significantly reduced the effect of AA (48.4±2.6 vs 59.5±3.1%). These data suggest activation of peripheral β-adrenoceptors in the delayed GE induced by phenylpyrazolone derivatives.

Severe hypertension in pregnancy: hydralazine or labetalol. A randomized clinical trial.

OBJECTIVE: The objective was to compare the safety and efficacy of intravenous labetalol and intravenous hydralazine for acutely lowering blood pressure in pregnancy. STUDY DESIGN: Two hundred women with severe hypertension in pregnancy were randomized to receive hydralazine (5 mg as a slow bolus dose given intravenously, and repeated every 20 min up to a maximum of five doses) or labetalol (20-mg intravenous bolus dose followed by 40 mg if not effective within 20 min, followed by 80 mg every 20 min up to a maximum dose of 300 mg). The primary end point was successful lowering of blood pressure and maternal hypotension. RESULTS: Women were similar with respect to characteristics at randomization. No significant differences were observed for maternal hypotension or persistent severe hypertension; only two patients in the hydralazine group presented with hypotension. Palpitations (p=0.01) and maternal tachycardia (p=0.05) occurred significantly more often in patients treated with hydralazine. The main neonatal outcomes were very similar per group; however, hypotension and bradycardia were significantly more frequent in the labetalol group. There were two neonatal deaths per antihypertensive drug group. CONCLUSIONS: This randomized clinical trial shows that labetalol and hydralazine fulfill the criteria required for an antihypertensive drug to treat severe hypertension in pregnancy.

Noradrenergic system interacts with genital reflexes induced by cocaine in paradoxical sleep-deprived male rats.

Different doses of alpha-1, alpha-2, beta-1, and beta-2 adrenoceptor agonists or antagonists were administered to paradoxical sleep-deprived (PSD) rats prior to cocaine administration. Methoxamine reduced the percentage of rats displaying erection, whereas prazosin did not. Yohimbine significantly decreased this percentage. For beta-1 adrenoceptor drugs, both compounds reduced the percentage of rats displaying erection at the highest dose; beta-2 adrenoceptor drugs had no effect. Except for clonidine, all drugs significantly reduced the frequency of erection. Ejaculation was significantly decreased following yohimbine and beta-1 drugs, whereas it was completely abolished by prazosin. The results showed that noradrenergic drugs inhibited genital reflexes in PSD rats, with distinct responses in relation to their respective action over the adrenoceptor.

Uso de los antagonistas Beta-adrenérgicos en la hipertensión arterial / Antagonist adrenergic beta use in the arterial hypertension

Los Betabloqueantes son drogas que inhiben competitivamente a los receptores beta-adrenérgicos, modulando la actividad de el sistema nervioso simpático. Estos son normalmente clasificados en base a su selectividad por los receptores beta. Los beta bloqueantes no selectivos, como propanolol, pindolol, nadolol, timolol y labetalol antagonizan los receptores B1 y B2. Los beta-bloqueantes selectivos, como el metoprolol, atenolol, esmolol y acebutolol tienen mayor afinidad por los receptores B-1. Los beta-bloqueantes selectivos están indicados en pacientes en quienes el bloqueo B-2 puede asociar un aumento en el riesgo de efectos adversos. Como en pacientes asmáticos o diabéticos, así como en pacientes con enfermedad vascular periférica o enfermedad de Raynaud. Algunos betabloqueantes tienen actividad agonista parcial (actividad simpático mimétrica intrínseca). Los beta-bloqueantes, como monoterapia o combinados con otras drogas han probado que tienen efectividad en la reducción de síntomas de angina de pecho y reducción de la morbi-mortalidad después del infarto al miocardio. Además son las drogas de elección en pacientes con hipertensión arterial e infarto al miocardio o angina. Muchos beta-bloqueantes son comúnmente usados en el tratamiento de pacientes con migraña recurrente, cardiomiopatía hipertrófica obstructiva, ansiedad aguda y en casos de glaucoma. En este artículo se presenta una revisión detallada sobre los beta-bloqueantes en el tratamiento de la hipertension arterial

Sympathetic innervation of mammary glands mediates suckling-induced reflex inhibition of milk yield in rats.

Previous work has shown that physiologic activation of the sympathetic system may inhibit milk yield (ME) in rats. Thus, adrenal catecholamines (CAs) are released by suckling, but it is not known whether such inhibition results also from reflex activation by the same stimulus of neural sympathetics upon the mammary gland. The present experiments were designed to determine whether suckling inhibits ME induced by oxytocin (OT) in the urethane-anesthetized lactating rat, and whether such inhibition results from adrenal and/or neurally released CAs. Rats were isolated (6 h) from their pups and then anesthetized. OT (0.8 mU every 2 min) was administered intravenously to the mothers during suckling. Rats were either chronically implanted with cannulae into the lateral cerebral ventricles (intracerebroventricularly), bilaterally adrenalectomized (ADX), hypophysectomized (HX), spinal cord transected (SCT: T3-T4), or had the nipple area (NA) locally anesthetized before suckling. MEs were low in control, sham, ADX and HX rats, but not in rats given the beta-adrenergic blocker propranolol (PROP; intravenously or intracerebroventricularly injected), nor in SCT, NA or PROP-HX rats. As revealed by ductal resistance measurements as an indicator of ductal tone, suckling-induced inhibition of ME was due to ductal constriction within the mammary glands. These effects of suckling, however, could be prevented by prior activation of ductal mechanoreceptors. Together, these results indicate that suckling inhibits ME through the reflex activation of neurally mediated central beta-adrenergic mechanisms, and that these effects, in turn, can be regulated by ductal mechanoreceptor activation.