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Biomedical subjects

R Astorga

Publications and source records attributed to R Astorga.

At least 55 records · Page 3Linked to original sources
PubMed1995

Growth hormone (GH) responses to the combined administration of GH-releasing hormone plus GH-releasing peptide 6 in adults with GH deficiency.

In recent years the health problems of adults with growth hormone deficiency (GHD) and the benefits of GH replacement therapy have received considerable attention. However, the reliability of conventional GH tests in the assessment of pituitary GH reserve in this group of patients is still controversial. In this study, we assessed GH secretion after the combined administration of GH-releasing hormone (GHRH) (1 microgram/kg iv) and GH-releasing peptide 6 (GHRP-6, 1 microgram/kg iv) in adult patients diagnosed with GHD by conventional GH testing, and correlate this response with insulin-like growth factor I levels. Twenty-one subjects (13 male, 8 female) with long-standing diagnosis of GHD aged 21-54 years were studied. In 13 subjects GH responses to GHRH plus GHRP-6 were markedly reduced (peak GH response < 10 mU/l), whereas in the remaining eight the response was greater (range 11-100 mU/l). In conclusion, our data show that combined administration of GHRH plus GHRP-6 elicited a significant increase in plasma GH levels in about 40% of patients diagnosed with GHD by conventional GH testing.

Adult↗
PubMed1995

Serological survey for avian paramyxoviruses from wildfowl in aquatic habitats in Andalusia.

A serological survey for a range of avian paramyxoviruses (PMV) was carried out among wildfowl from southern Spain, 1990 to 1992, using the hemagglutination inhibition technique. We collected 579 sera from 24 avian families (18 aquatic and six non-aquatic). Antibodies were detected to all paramyxoviruses in waterfowl, with a notable prevalence of antibodies to PMV-8 (43%) and to a lesser extent PMV-6 (21%). By contrast, in non-aquatic species high antibody prevalences were detected only to PMV-2 (60%), particularly in sparrows (68%), while antibody prevalences to other PMV's were moderate or low.

Animals↗
PubMed1994

[Long-acting and repeatable dose bromocriptine in the prolonged treatment of prolactinoma].

BACKGROUND: The presentations of intravenous or depot bromocriptine (bromocriptine LA or long acting, Pariodel LA and bromocriptine LAR or long acting repeatable, Pariodel LAR) have improved the efficacy and the tolerance of oral bromocriptine. In contrast to bromocriptine LA, bromocriptine LAR may be repeatedly administered intramuscularly. METHODS: Five patients with macroprolactinoma and 4 with microprolactinoma were included in the study. A 50 mg bottle of bromocriptine LAR was administered intramuscularly every month, over a minimum period of 6 months. PRL was determined prior to the study, 1, 3, 7, 14, and 28 days following the initial dose of bromocriptine and thereafter with monthly periodicity. RESULTS: The PRL values decreased in those patients with macroprolactinomas following the administration of bromocriptine LAR; in 2 patients the monthly doses of bromocriptine LAR was increased to 100 mg since the month after the initial dose PRL remained greater than 200 ng/ml with serum RPL normalizing in most of the patients at 6 months of treatment. In two of the three patients who presented visual changes a clear improvement was observed and in all the cases a reduction in the size of the macroprolactinoma was found upon CAT control at 6 months. The PRL values also decreased in the patients with microprolactinomas following administration of bromocriptine LAR, although the response was not as homogeneous as in the patients with macroprolactinomas due to that at 6 months 2 patients continued to have slightly elevated serum PRL levels. The microadenoma persisted in the control CAT at 6 months except in one case. Local and general tolerance to bromocriptine LAR was very good. CONCLUSIONS: This study indicates good tolerance to bromocriptine LAR, being a therapeutic option in the treatment of macroprolactinomas.

Adult↗
PubMed1994

Prevalence of antibodies to different Leptospira interrogans serovars in pigs on large farms.

A seroepidemiological survey was carried out in the province of Badajoz (south-western Spain) in order to determine the presence and spread of Leptospira interrogans. The 521 sera tested were drawn from breeding sows on 28 large farms (15 with fewer than 60 and 13 with over 60 breeders). Immunological testing was performed using the Martin-Pettit micro-agglutination technique. Pigs with titres equal to or greater than 1:100 were considered positive. Haemolysed and/or contaminated test sera were reprocessed following filter-paper treatment. A total of 10.56% of pigs tested proved positive, 39.28% of farms being affected. The following L. interrogans serovars were detected: pomona (6.53%), castellonis (1.15%), sejroe (1.15%), grippotyphosa (0.96%), australis (0.38%), hebdomadis (0.19%) and icterohaemorrhagiae (0.19%).

Animals↗
PubMed1993

Transmissible gastroenteritis in pigs in south east Spain: prevalence and factors associated with infection.

In the Murcia region of south east Spain, epidemics of transmissible gastroenteritis-like disease have occurred in pigs every three years since 1980. In 1987 a sero-epidemiological survey was conducted to estimate the prevalence and spread of transmissible gastroenteritis virus (TGEV) infection among breeding pigs and farms, and to determine any association between the infection and herd size and geographical zone. The Murcia region was divided into four geographical zones and the farms were classified by size into four categories. The random sample was statistically representative of both the breeding stock and the farms in each geographical zone, and the analyses involved 6000 breeding pigs from 480 farms. The immunological techniques employed were the indirect ELISA and the blocking ELISA. The prevalence of seropositive breeding pigs was 1.27 +/- 0.28 per cent and the prevalence of infected farms was 5 +/- 1.94 per cent. On the infected farms, the prevalence of seropositive pigs ranged from 5 to 60 per cent. The infection occurred throughout the Murcia region, but a significant association (P < 0.01) was observed between the geographical zone and the prevalence of TGEV infection. Herds with > or = 50 breeding pigs had a greater prevalence (P < 0.01) of TGEV infection.

Animals↗
PubMed1993

Growth hormone releasing hormone priming increases growth hormone secretion in patients with Cushing's syndrome.

OBJECTIVE: In patients with Cushing's syndrome, decreased growth hormone (GH) secretion is observed though the basic mechanism is unknown. In states of chronic deficiency of hypothalamic growth hormone releasing hormone (GHRH) release, a blunted GH response to exogenous GHRH has been reported; such impairment can be partially normalized by repetitive GHRH administration (priming). In order to clarify whether a deficit in hypothalamic release of GHRH is the basis of the decreased GH secretion in patients with Cushing's syndrome, GHRH plus pyridostigmine tests were undertaken, both before and after GHRH priming. DESIGN: GHRH (200 micrograms/day as a single s.c. injection) was given daily over 7 days. Two pyridostigmine (120 mg p.o.) plus GHRH (100 micrograms i.v.) tests were performed before and after priming to assess GH response. PATIENTS: Eight patients (seven women, one man), with untreated Cushing's syndrome (six Cushing's disease, one autonomous bilateral adrenal hyperplasia, one adrenal adenoma), were studied. MEASUREMENTS: Plasma GH levels were measured by immunoradiometric assay. RESULTS: GHRH plus pyridostigmine-induced GH release was impaired in patients with untreated Cushing's syndrome (mean peak 5.2 +/- 1.4 mU/l, area under the curve (AUC) 472 +/- 96). Repetitive administration of GHRH over 7 days partially restored the GH response to the second pyridostigmine-GHRH test (mean peak 15.0 +/- 2.1 mU/l. AUC 1016 +/- 104), both P < 0.05. All of the eight Cushing's syndrome patients studied presented a higher GHRH plus pyridostigmine-induced GH secretion after priming. CONCLUSIONS: Repetitive administration of GHRH increases the pyridostigmine-GHRH-induced GH secretion in patients with Cushing's syndrome. This suggests that impaired hypothalamic release of GHRH is a contributing factor to the decreased GH secretion observed in chronic hypercortisolism.

Adult↗
PubMed1993

Clinical use of octreotide in unresectable meningiomas. A report of three cases.

Unresectable meningioma is the cause of a serious clinical problem, for whom no satisfactory mode of treatment is currently available. Meningiomas are known to have receptors for diverse hormones. In this sense, somatostatin receptors were found in every meningioma specimen studied in a recent report. In addition, somatostatin has been able to inhibit meningioma cell proliferation in vitro. A brief report of clinical use of somatostatin long-life analogue octreoctide upon three patients diagnosed of unresectable meningioma is here presented. Doses used were gradually increased up to 1000, 900 and 1500 micrograms/24 h during 16, 6 and 7 weeks, respectively. There was an almost perfect tolerance to the drug (in one case a mild and transient abdominal discomfort and diarrhea could be observed). An important alleviation of headaches in 2 cases, and a transient but objective improvement in ocular movements and signs in 1 case were noticed. No change (neither growth nor shrinkage) was observed by CT scan at the end of treatment course in the three cases studied. In 1 case a partial resection was performed and tissue specimen was found to contain somatostatin receptors. Although in our very limited experience no brilliant results are presented, duration of treatment or doses used could have been insufficient. Data herein presented seem to support recently reported findings in which no growth inhibition of meningioma cells cultured in vitro by adding octreoctide to the medium was observed. So, in our opinion, clinical use of octreoctide on unresectable meningioma deserves further experience, that must be carried out with great caution.

Adult↗
PubMed1991

Acromegalic cardiopathy improves after treatment with increasing doses of octreotide.

The aim of this study was to assess the effects a long-acting somatostatin analogue (octreotide) had on the heart function of acromegalic patients. Five patients fulfilling clinical criteria of active acromegaly without symptoms of heart dysfunction, were treated with increased doses of octreotide (300, 600, 900, 1,200 and 1,500 micrograms/daily) over a period of six months. Growth hormone (GH) profiles were carried out during each different dose of octreotide. M-Mode, two dimensional and Doppler echocardiographic evaluation were performed both before and after treatment. Although the GH levels of all patients dropped after each increment of the octreotide, the responses were not homogeneous. Six months after the onset of treatment, echocardiographic studies revealed a significant reduction in the interventricular septum thickness (IVST) (p less than 0.05) and Doppler analyses showed an increase in the early diastolic transmitral flow velocity (p less than 0.05). Our results indicate that octreotide is capable of reversing acromegalic cardiopathy, since it not only reduces GH levels to within normal limits but improves left ventricular hypertrophy and distensibility without modifying contractility.

Acromegaly↗
PubMed1991

[Trials of acute treatment with SMS 201-995 in acromegalics].

The results of two acute treatment tests using SMS 201-995 (SMS), over a 24 hour period in acromegalic patients are presented. Test number 1: Seventeen cases with a mean age of 44.3 +/- 11.9 (21/71) years with an evolution of 9.2 +/- 6.5 (2/20) years and GH of 30.1 +/- 21.1 (5.2/96.4) ng/ml were treated with 50 micrograms/8 hours (8, 16, and 24 hours) of subcutaneous SMS. Test number 2: 26 cases with a mean age of 45.5 +/- 15.5 (21/71) years with an evolution of 9.1 +/- 7.9 (2/35) years and GH of 28.6 +/- 22.2 (5.2/96.4) ng/ml were treated with 100 micrograms/8 hours (8, 16, and 24 hours) of subcutaneous SMS. Ten point GH profile in 24 hours is evaluated in both tests and in number 2 insulin and blood sugar levels are measured at the same time points. In both tests GH is significantly reduced being the 100 micrograms/8 hour treatment schedule more efficient. The results in the decrease of GH in test number two are related to those obtained using SMS in prolonged treatments. Inspire of the reducing effect that SMS has on insulin levels, its influence on the blood sugar profile is scare.

Acromegaly↗
PubMed1991

[Results of trans-sphenoidal surgery for the treatment of acromegaly].

UNLABELLED: During the past 17 years (1972-89) 55 transsphenoidal surgery (TSS) interventions were performed in our Hospital in 53 cases of acromagaly (2 cases underwent surgery twice). RESULTS: 22 were cured (40%); 15 partial efficacy (27%) and 18 negative efficacy (33%). Mean GH values (ngr/ml) before surgery were: Cured cases 15.8 + 12.9 (p = 0.0015). Basal GH values above 40 ngr/ml obscure the prognosis of TSS in acromegaly. Cure was perfectly achieved in smaller size hypophysis adenomas (Hardy Grade land 11 in CT scan). The complications in the early post-surgery were rare and transient. Chronic sequelae due to TSS occurred in 7 cases (13.5%), as complete or partial anterior hypophysis failure. TSS is the treatment of choice of acromegaly in our environment, however a significant number of cases do not achieve cure and need to complete treatment with hypophyseal radiotherapy.

Acromegaly↗
PubMed1990

Effect of enhancement of endogenous cholinergic tone with pyridostigmine on growth hormone (GH) responses to GH-releasing hormone in patients with Cushing's syndrome.

Growth hormone (GH) secretion in patients with Cushing's syndrome is diminished to all the stimuli tested so far but the precise mechanisms through which this occurs are unknown. In order to investigate whether increased somatostatinergic tone might be responsible for this alteration, we studied the effect of pyridostigmine (120 mg p.o. at -60 min), which activates cholinergic synapses and thus suppresses hypothalamic somatostatin release on GH responses to GHRH (100 micrograms, i.v. at 0 min), in six patients with Cushing's syndrome. We found that while pyridostigmine markedly potentiated GH responses to GHRH, in all the normal subjects tested (n = 12), neither GHRH alone nor GHRH plus pyridostigmine elicited any increase in GH secretion in any of the patients with Cushing's syndrome. This suggests that chronic glucocorticoid excess induces marked alterations in the hypothalamic control of GH secretion.

Adult↗
PubMed1990

Evaluation of the pituitary-adrenal axis before, during and after pituitary adenomectomy. Is perioperative glucocorticoid therapy necessary?

Under the supposition that ACTH secretion will be compromised by surgical trauma, patients with pituitary adenomas undergoing transsphenoidal adenomectomy are frequently given corticoids, even though this therapy is controversial. We studied 10 patients with pituitary adenomas whose adrenocortical function was sufficient prior to surgery. The ACTH and cortisol levels rose significantly during surgery in all of these patients. Five patients completed a two-year postoperative follow-up period and their ACTH and cortisol values remained within normal limits. It may be that patients undergoing transsphenoidal surgery for pituitary adenomas do not need perioperative glucocorticoid treatment, since the hypophyseal-adrenal axis does retain its integrity.

Adenoma↗
PubMed1989

Arterial hypertension as a complication of prolonged ketoconazole treatment.

Two of 14 patients with Cushing's syndrome treated on a long-term basis with ketoconazole developed sustained hypertension. In both cases normal plasma and urinary free cortisol levels had been achieved following ketoconazole therapy, yet continuous blood pressure monitoring demonstrated hypertension 31 (patient 1) and 52 weeks (patient 2) after treatment. In patient 1, plasma levels of deoxycorticosterone and 11-deoxycortisol were elevated. In patient 2, in addition to an increase in both deoxycorticosterone and 11-deoxycortisol levels, plasma aldosterone values were raised, with a concomitant suppression of renin levels. Our findings show that long-term treatment with high doses of ketoconazole may induce enzyme blockade leading to mineralocorticoid-related hypertension.

Adolescent↗
PubMed1989

Rapid improvement of visual defects with parenteral depot-bromocriptine in a patient with a non-functioning pituitary adenoma.

The management of non-functioning pituitary adenomas with bromocriptine is controversial, and surgical treatment is usually prescribed when the visual field is affected. Here we report, what we believe to be the first case of a patient with a non-functioning pituitary adenoma who experienced normalization of visual field defects and a substantial improvement in visual acuity after the parenteral administration of depot-bromocriptine. The patient's tolerance to the drug was excellent. The results of the immunohistochemical study of the surgically removed tumor were negative for PRL, GH, LH, FSH, TSH and ACTH. In our opinion, the use of depot-bromocriptine may represent an alternative to surgery in patients with non-functioning pituitary adenomas associated with visual lesions.

Adenoma↗
PubMed1989

In vitro effects of ketoconazole on corticotrope cell morphology and ACTH secretion of two pituitary adenomas removed from patients with Nelson's syndrome.

The direct effects of ketoconazole on the secretion of ACTH by human pituitary adenoma cells from 2 patient with Nelson's syndrome were studied in vitro. Stereologically quantified, intracellular changes affect the surface density of the endoplasmic reticulum (it decreased by 73%), the volume density of the secretion granules (it decreased by 49%), and the volume density of lysosomes (it decreased by 67%). The hormone released in the culture medium decreased depending on the doses of ketoconazole used; 10 mumol/l decreased ACTH levels by 31%. These data show that ketoconazole induce marked changes on corticotrope morphology and ACTH secretion in pituitary cells obtained from patients with Nelson's syndrome.

Adenoma↗
PubMed1988

Contrasting features of insulin dependent diabetes mellitus associated with neuroectodermal defects and classical insulin dependent diabetes mellitus.

The Wolfram, or DIDMOAD, syndrome is a rare congenital disease that is associated with diabetes insipidus, insulin dependent diabetes mellitus of an early onset, bilateral optic atrophy and deafness. Urological disorders are usually present as well. We have studied nine patients belonging to five different families. All of the family members were HLA typed (including DR), and islet cell as well as antinuclear antibody determinations were carried out. Although individuals with insulin dependent diabetes mellitus are very prone to have either HLA-DR3 or -DR4 antigens, none of our patients had DR3 antigens and only one was DR4 positive. On the other hand, three of our patients were typed as HLA-DR2 positive. This antigen is uncommon in classical insulin dependent diabetes. In one of the families, the affected siblings did not share the same HLA haplotype. Islet cell and antinuclear antibodies were not found in any of the cases and six of the patients had a small, but significant, insulin secretory reserve. On the basis of some of the clinical features it was also possible to further distinguish between the DIDMOAD syndrome and the classical insulin dependent diabetes mellitus. The differences encountered between classical and DIDMOAD insulin dependent diabetes mellitus--the presence/absence of HLA linkage, HLA-DR2, -DR3 and -DR4 associations, islet cell or antinuclear antibodies, the tendency to ketosis and diabetic retinopathy--indicate that their etiopathogenies are triggered by distinct mechanisms.

Adolescent↗