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1.
Arq. bras. med. vet. zootec. (Online) ; 72(4): 1441-1448, July-Aug. 2020. tab
Article in Portuguese | LILACS, VETINDEX | ID: biblio-1131488

ABSTRACT

A mastite bovina, uma das principais doenças do rebanho leiteiro, caracteriza-se por um processo inflamatório no úbere. A inviabilidade econômica, o impacto ambiental negativo e os resíduos antimicrobianos têm estimulado a pesquisa de outros tratamentos alternativos para a prevenção e o tratamento de doenças na bovinocultura leiteira. O betaglucano é um agente imunomodulador com potencial ação preventiva para doenças infecciosas, inclusive a mastite. Este estudo teve como objetivo avaliar a eficácia do uso do betaglucano, por meio de administração oral, em animais em lactação. Foram utilizadas 20 vacas lactantes, distribuídas em dois grupos, um controle e um tratamento, com 10 animais em cada grupo. O grupo tratamento recebeu 5g/dia, durante 60 dias, de 1,3-1,6 betaglucano isolado da parede celular de Saccharomyces cerevisiae diluído em ração após a ordenha, enquanto o grupo controle recebia somente a ração. Foram realizados os testes de California Mastitis Test (CMT), contagem de células somáticas (CCS), produção de leite e percentual de gordura e proteína no leite. Não houve diferença estatisticamente significativa entre os grupos quanto à CCS, ao CMT, à composição do leite ou produção. Não se observou, portanto, eficácia do uso do betaglucano purificado, administrado por via oral, no controle e na prevenção da mastite em vacas leiteiras, quando comparadas com o grupo controle. Atribuem-se esses resultados, principalmente, à degradação ruminal do produto testado. Sugerem-se, portanto, mais pesquisas utilizando o 1,3-1,6 betaglucano purificado de parede de S. cerevisiae por outras vias de administração, tais como intramamária e subcutânea.(AU)


Bovine mastitis, one of the main diseases of dairy herds, is characterized by an inflammatory process in the udder. The economic and environmental impacts, as well as the residues of antimicrobial drugs have stimulated the research of novel alternative treatments for the prevention and treatment of diseases in dairy production cows. The beta-glucan is an immunomodulator agent, with potential preventive action for infectious diseases, including mastitis. This study aimed to assess the effectiveness of orally administered beta-glucan in lactating cows. 20 lactating cows were used, distributed into two groups, one control and one treatment, with 10 cows in each group. The treatment group received 5g of 1.3-1.6 betaglucan daily for 60 days, isolated from the cell-wall of Saccharomyces cerevisiae diluted into a grain meal, whereas the animals in the control group received only the ration. The California Mastitis Test (CMT), Somatic Cells Counting (SCC), daily production and assessments of fat and protein content in milk were done. There was no statistically significant difference between the groups concerning subclinical mastitis detected by CMT, SCC, milk production and composition regarding protein and fat content. It was not observed, therefore, the effectiveness of the use of purified beta-glucan orally administered on the control or prevention of mastitis in dairy cows. The results are attributed to the ruminal degradation of the product tested. It is, therefore, suggested that more research should be conducted using the 1.3-1.6 beta-glucan purified from the cell wall of S. cerevisiae by other administration means and ruminal protection technologies for the isolated beta-glucan.(AU)


Subject(s)
Animals , Cattle , Saccharomyces cerevisiae , beta-Glucans/administration & dosage , Mastitis, Bovine/prevention & control , Dietary Supplements/analysis , Prebiotics/administration & dosage , Immunologic Factors/administration & dosage
2.
Osteoporos Int ; 29(11): 2537-2543, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30043107

ABSTRACT

To evaluate bone mineral density (BMD) and morphometric vertebral fractures (MVF) in chronic obstructive pulmonary disease (COPD) patients in comparison with two control groups. BMD was lower in the disease group (DG) and was associated with the worst disease severity and prognosis. The prevalence of MVF was high and greater in the DG than in the control groups. INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is associated with osteoporosis and vertebral fractures. It is still unclear whether the presence of fractures and changes in bone mineral density (BMD) are associated with disease severity and prognosis. The aim of this study was to evaluate BMD and morphometric vertebral fractures (MVF) in COPD patients in comparison with two control groups and to correlate these parameters with indices of COPD severity (VEF1 and GOLD) and prognosis (BODE). METHODS: This was a cross-sectional study in COPD patients (disease group, DG) who underwent BMD and vertebral fracture assessment (VFA). Two control groups were used: smokers without COPD (smoker group, SG) and healthy never-smoker individuals (never-smoker group, NSG). RESULTS: The DG comprised 121 patients (65 women, mean age 67.9 ± 8.6 years). Altered BMD was observed in 88.4% of the patients in the DG, which was more prevalent when compared with the control groups (p < 0.001). The BMD values were lower in the DG than in the control groups (p < 0.05). BMD was associated with the worst disease severity and prognosis (p < 0.05). The prevalence of MVF was high (57.8%) and greater than that in the SG (23.8%) and the NSG (14.8%; p < 0.001). The prevalence of fractures was not associated with disease severity and prognosis. CONCLUSIONS: COPD patients have a higher prevalence of MVF and low BMD, and the latter was associated with the severity and poor prognosis of the disease.


Subject(s)
Bone Density/physiology , Osteoporosis/etiology , Osteoporotic Fractures/etiology , Pulmonary Disease, Chronic Obstructive/complications , Spinal Fractures/etiology , Aged , Case-Control Studies , Cross-Sectional Studies , Female , Femur/physiopathology , Femur Neck/physiopathology , Forced Expiratory Volume/physiology , Humans , Lumbar Vertebrae/physiopathology , Male , Middle Aged , Osteoporosis/physiopathology , Osteoporotic Fractures/physiopathology , Prognosis , Pulmonary Disease, Chronic Obstructive/physiopathology , Severity of Illness Index , Smoking/adverse effects , Smoking/physiopathology , Spinal Fractures/physiopathology
3.
Diabetes Obes Metab ; 13(11): 1036-46, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21682834

ABSTRACT

AIM: The purpose of this study was to evaluate if superior glycaemic control could be achieved with Avandamet® (rosiglitazone/metformin/AVM) compared with metformin (MET) monotherapy, and if glycaemic effects attained with AVM are durable over 18 months of treatment. Bone mineral density (BMD) and bone biomarkers were evaluated in a subgroup of patients. METHODS: This was a phase IV, randomized, double-blind, multi-centre study in 688, drug naÏve, male and female patients who had an established clinical diagnosis of type 2 diabetes mellitus (T2DM). Patients were randomized in a 1 : 1 ratio either to AVM or MET. RESULTS: As initial therapy in patients with T2DM, AVM was superior to MET in achieving statistically significant reductions in glycated haemoglobin (HbA1c) (p < 0.0001) and fasting plasma glucose (FPG) (p < 0.001), with more patients reaching recommended HbA1c and FPG targets for intensive glycaemic control. The glycaemic effects attained with AVM compared to MET monotherapy were durable over 18 months of treatment. In the bone substudy, AVM was associated with a significantly lower BMD in comparison with MET at week 80 in the lumbar spine and total hip (p < 0.0012 and p = 0.0005, respectively). Between-treatment differences were not statistically significant for distal one-third of radius BMD, femoral neck BMD or total BMD. CONCLUSION: Superior glycaemic control was achieved with AVM compared with MET monotherapy. The superior glycaemic effects were shown to be durable over 18 months of treatment. AVM was associated with a significantly reduced BMD in comparison with MET at week 80 in the lumbar spine and total hip.


Subject(s)
Blood Glucose/drug effects , Bone Density/drug effects , Diabetes Mellitus, Type 2/drug therapy , Glycated Hemoglobin/drug effects , Hypoglycemic Agents/therapeutic use , Metformin/therapeutic use , Thiazoles/therapeutic use , Adolescent , Adult , Aged , Biomarkers/metabolism , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/metabolism , Double-Blind Method , Drug Combinations , Female , Glycated Hemoglobin/metabolism , Humans , Male , Middle Aged , Treatment Outcome , Young Adult
4.
Ultrasonics ; 44 Suppl 1: e667-72, 2006 Dec 22.
Article in English | MEDLINE | ID: mdl-16797644

ABSTRACT

Air coupled piezoelectric ultrasonic array transducers are a novel tool that could lead to interesting advances in the area of non-contact laminar material testing using Lamb wave's propagation techniques. A key issue on the development of such transducers is their efficient coupling to air media (impedance mismatch between the piezoelectric material and air is 90 dB or more). Adaptation layers are used in order to attain good matching and avoid possible serious signal degradation. However, the introduction of these matching layers modify the transducer surface behaviour and, consequently, radiation characteristics are altered, making the usual idealization criteria (of uniform surface movement) adopted for field simulation purposes inaccurate. In our system, we have a concave linear-array transducer of 64 elements (electrically coupled by pairs) working at 0.8 MHz made of PZ27 rectangular piezoceramics (15 mm x 0.3 mm) with two matching layers made of polyurethane and porous cellulose bonded on them. Experimental measurements of the acoustic aperture of single excited array elements have shown an increment on the geometrical dimensions of its active surface. A sub-millimeter vibrometer laser scan has revealed an extension of the aperture beyond the supposed physical single array element dimensions. Non-uniform symmetric apodized velocity surface vibration amplitude profile with a concave delay contour indicates the presumed existence of travelling wave phenomena over the surface of the outer array matching layer. Also, asymptotic propagation velocities around 2500 m/s and attenuation coefficient between 15 and 20 dB/mm has been determined for the travelling waves showing clear tendencies. Further comparisons between the experimental measurements of single array element field radiation diagram and simulated equivalent aperture counterpart reveal good agreement versus the ideal (uniform displaced) rectangular aperture. For this purpose an Impulse Response Method (IRM) has been used.

5.
Arq Gastroenterol ; 35(2): 104-9, 1998.
Article in Portuguese | MEDLINE | ID: mdl-9814375

ABSTRACT

In order to establish which are the most frequent endoscopic detectable colorectal disorders in AIDS patients with intestinal complaints we analysed 236 colonoscopies in a series of 186 patients. The colonoscopic procedure was always followed by biopsies, even in the absence of macroscopic lesions. The most frequent diagnosis was colitis due to citomegalovirus infection observed in 64 exams (27.1%) and presented with an inflammatory pattern with ulcers, followed by Cryptosporidium sp., found in 31 exams (13.1%). This infection, conversely, presented as an inflammatory non-ulcerative lesion. Others pathogens found in lower frequency were: Mycobacterium sp., Histoplasma capsulatum, Herpes simplex, Isospora sp., Giardia sp., Candida sp. and Campilobacter sp.. Neoplastic lesions, mostly Kaposy's sarcoma, were detected in 10 of the colonoscopies (4.2%). The most frequent colorectal disorders in AIDS patients detected by endoscopic procedures are citomegalovirus and Cryptosporidium infection. Biopsies are always necessary to confirm the endoscopic diagnosis and to identify the presence of associated pathogens.


Subject(s)
Acquired Immunodeficiency Syndrome/complications , Colonic Diseases/complications , Colonic Diseases/diagnosis , Colonoscopy , Rectal Diseases/complications , Rectal Diseases/diagnosis , Adult , Aged , Female , Humans , Male , Middle Aged
6.
J Clin Densitom ; 1(1): 75-6, 1998.
Article in English | MEDLINE | ID: mdl-15304915
7.
J Pediatr Orthop ; 16(4): 508-13, 1996.
Article in English | MEDLINE | ID: mdl-8784708

ABSTRACT

Sprengel deformity of the shoulder is characterized by elevation and medial rotation of the inferior pole of the scapula. Surgical treatment is recommended in significantly involved patients to improve cosmetic appearance and function of the involved shoulder. We report long-term results of a Woodward procedure modified by excision of the prominent superomedial border of the scapula for correction of this deformity in 15 patients. Preoperatively, the total abduction of the shoulder averaged 115 degrees, and on follow-up the abduction had improved to an average of 150 degrees. In all patients except one, there was marked improvement in appearance as assessed on Cavendish scale. All patients except two had achieved skeletal maturity at the last follow-up. Eighty-six percent of patients expressed satisfaction with operative results. Our data support the concept that correction achieved by a modified Woodward procedure is not altered by growth and is maintained beyond skeletal maturity.


Subject(s)
Scapula/abnormalities , Scapula/surgery , Shoulder/abnormalities , Shoulder/surgery , Adolescent , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Orthopedics/methods , Osteotomy , Retrospective Studies , Treatment Outcome
8.
J Pediatr Orthop ; 15(5): 596-8, 1995.
Article in English | MEDLINE | ID: mdl-7593569

ABSTRACT

Fourteen patients with Köhler's bone disease of the tarsal navicular in 16 feet were reviewed at an average follow-up of 31 years 6 months after diagnosis. The type and length of treatment did not affect the final outcome; however, short-leg cast immobilization did decrease the duration of symptoms. Two feet were symptomatic at the time of follow-up: one foot had a talocalcaneal coalition with degenerative changes, and the other foot had a large accessory navicular. Both of these feet were rated as having a fair result. The remaining 12 feet were classified as having a good result. Patients with Köhler's bone disease can be expected to have a normal foot at adulthood. Should the patient become symptomatic, other causes of foot pain should be investigated.


Subject(s)
Osteochondritis/therapy , Tarsal Bones , Child , Child, Preschool , Female , Follow-Up Studies , Humans , Male , Osteochondritis/complications , Osteochondritis/pathology , Retrospective Studies , Tarsal Bones/pathology , Treatment Outcome
9.
J Bone Joint Surg Am ; 77(7): 975-84, 1995 Jul.
Article in English | MEDLINE | ID: mdl-7608240

ABSTRACT

Fifty-five boys with seventy-eight congenitally dislocated hips were treated between 1965 and 1990. The patients were divided into three groups according to the initial treatment. Group I included thirty hips (twenty-two boys) that had been treated initially with a Pavlik harness. Two hips (7 per cent) had a successful outcome, and twenty-eight (93 per cent) needed additional methods of treatment. Group II included forty-two hips (twenty-nine boys) that had been treated initially with closed reduction and immobilization in a hip-spica cast. After the closed reduction, twenty-nine hips (69 per cent) were considered stable, although fifteen (52 per cent) of them needed a secondary procedure because of residual subluxation or persistent acetabular dysplasia. Thirteen hips (31 per cent) were considered unstable after the closed reduction and subsequently had an open reduction. Group III included six hips (four boys) that had been treated initially with open reduction. Two of these hips redislocated after the open reduction, and they were reduced with an additional open reduction. A pelvic osteotomy was later performed to treat persistent acetabular dysplasia in these two hips. Two hips that had been treated with an open reduction and concomitant pelvic and femoral procedures did not need additional treatment. This study demonstrates that boys who have congenital dislocation of the hip do not always respond well to treatment and constitute a high-risk group.


Subject(s)
Hip Dislocation, Congenital/therapy , Casts, Surgical , Follow-Up Studies , Hip Dislocation, Congenital/diagnostic imaging , Hip Dislocation, Congenital/surgery , Humans , Infant , Infant, Newborn , Male , Osteotomy , Radiography , Recurrence , Retrospective Studies , Treatment Outcome
10.
Acta Med Port ; 7 Suppl 1: S61-6, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7653283

ABSTRACT

Infection caused by Toxoplasma gondii is a frequent event in Portugal. When this occurs in immunocompetent individuals, it is rarely a matter of concern; the contrary occurs with immunosuppressed patients or in pregnancy. Transplant patients are treated with immunosuppressive drugs which mainly disturb their mechanisms of cellular immunity, and that opens the way to infections by opportunistic intracellular microorganisms. We recently treated a renal transplant patient who suffered from cerebral toxoplasmosis, and this provided an opportunity for a review of the other 20 patients reported in medical literature to date.


Subject(s)
Kidney Transplantation , Opportunistic Infections/diagnosis , Postoperative Complications/diagnosis , Toxoplasmosis, Cerebral/diagnosis , Adult , Brain/diagnostic imaging , Brain/pathology , Humans , Immunosuppression Therapy/adverse effects , Magnetic Resonance Imaging , Male , Opportunistic Infections/etiology , Postoperative Complications/etiology , Recurrence , Tomography, X-Ray Computed , Toxoplasmosis, Cerebral/etiology
11.
J Pediatr Orthop ; 14(3): 383-4, 1994.
Article in English | MEDLINE | ID: mdl-8006175

ABSTRACT

A radiolucent spine frame for obtaining intraoperative spine radiographs while performing surgery for scoliosis has been designed at the Alfred I. duPont Institute and is described here. This frame, constructed of strong radiolucent plastic compounds, is easy to use and maintain.


Subject(s)
Scoliosis/surgery , Spine/diagnostic imaging , Technology, Radiologic/instrumentation , Child , Humans , Radiography
14.
Acta Med Port ; 6(3-4): 157-63, 1993.
Article in Portuguese | MEDLINE | ID: mdl-8317235

ABSTRACT

Infection caused by Toxoplasma gondii is a frequent event in Portugal. When this occurs in immunocompetent individuals it is rarely a matter of concern; the contrary occurs with immunosuppressed patients or in pregnancy. Transplant patients are treated with immunosuppressive drugs which mainly disturb their mechanisms of cellular immunity, and that opens the way to infections by opportunistic intracellular microorganisms. We recently treated a renal transplant patient who suffered from cerebral toxoplasmosis, and this provided an opportunity for a review of the other 20 patients reported in medical literature to date.


Subject(s)
Kidney Transplantation/adverse effects , Postoperative Complications/diagnosis , Toxoplasmosis, Cerebral/diagnosis , Adult , Animals , Antibodies, Protozoan/blood , Brain/diagnostic imaging , Brain/pathology , Humans , Immunocompromised Host/immunology , Kidney Transplantation/immunology , Magnetic Resonance Imaging , Male , Tomography, X-Ray Computed , Toxoplasma/immunology
15.
Dis Colon Rectum ; 34(10): 917-20, 1991 Oct.
Article in English | MEDLINE | ID: mdl-1717210

ABSTRACT

The present study was performed to identify tumor cells in lymph nodes from colorectal adenocarcinomas considered free of disease by the classic hematoxylin-eosin stain, based on the detection of the carcinoembryonic antigen (CEA) and cytokeratins in neoplastic epithelial cells. For this purpose, 603 lymph nodes from 46 lesions were stained by the peroxidase-antiperoxidase technique. Tumor cells were detected in 22 nodes from 12 patients, mainly in the subcapsular sinuses, permitting a restaging of these patients into two groups: those now considered to have metastatic disease and those free of metastases. However, the 5-year follow-up showed no statistical differences in survival between the two groups.


Subject(s)
Adenocarcinoma/pathology , Carcinoembryonic Antigen/analysis , Colorectal Neoplasms/pathology , Keratins/analysis , Neoplasm Staging/methods , Adenocarcinoma/mortality , Colorectal Neoplasms/mortality , Follow-Up Studies , Humans , Immunoenzyme Techniques , Lymphatic Metastasis , Macrophages/pathology
16.
AMB Rev Assoc Med Bras ; 36(2): 97-9, 1990.
Article in Portuguese | MEDLINE | ID: mdl-1965673

ABSTRACT

The authors present their experience with the totally implanted vascular reservoirs for chemotherapy. Thirty-one reservoirs were implanted in 29 patients. Complications were observed in 19.3% of the cases imposing the removal of 12.9% of them. No reservoir have been lately removed because of infection or obstruction. Based on their results, the authors conclude that the totally implanted reservoir is extremely helpful for patients submitted to chemotherapy for long periods.


Subject(s)
Antineoplastic Agents/administration & dosage , Catheterization, Central Venous/instrumentation , Catheters, Indwelling , Neoplasms/drug therapy , Adolescent , Adult , Aged , Catheterization, Central Venous/adverse effects , Child , Female , Humans , Male , Middle Aged
17.
J Endocrinol Invest ; 10(5): 427-33, 1987 Oct.
Article in English | MEDLINE | ID: mdl-3323290

ABSTRACT

We investigated the influence of calcium ions on the secretion of anterior pituitary hormones basally and in response to exogenous hypothalamic releasing factors in 6 men with pituitary tumors. To this end, concentrations of LH, FSH, TSH, growth hormone and prolactin were measured in blood collected at 10-min intervals basally and during a continuous infusion of combined TRH (2 micrograms/min) and GnRH (1 microgram/min). Study sessions were randomized to iv saline, calcium, or diltiazem infusions or oral diltiazem administration. Our results indicate that in contrast to responses in normal men, iv calcium injections do not suppress circulating prolactin concentrations in patients with prolactin-secreting pituitary tumors. Moreover, neither oral diltiazem administration for one week nor acute iv diltiazem infusion suppressed the hyperprolactinemia of tumor patients. However, there were significant effects of drug and calcium treatments on serum concentrations of FSH, GH and testosterone, but not LH or TSH. Moreover, during GnRH-TRH stimulation, there were significant differences in LH, TSH, and testosterone responses in tumor patients compared to normal men. In summary, iv calcium infusion was associated with invariant basal release of anterior pituitary tumoral hormones in patients with pituitary adenomas. However, there were significant differences in the GnRH/TRH-stimulated release of certain anterior pituitary hormones in tumor patients compared to normal men in response to iv calcium and the calcium-channel antagonist, diltiazem.


Subject(s)
Adenoma/blood , Calcium/pharmacology , Diltiazem/pharmacology , Pituitary Hormones, Anterior/blood , Pituitary Neoplasms/blood , Adult , Aged , Calcium/blood , Diltiazem/blood , Humans , Male , Middle Aged , Pituitary Gland, Anterior , Pituitary Hormone-Releasing Hormones/physiology , Random Allocation , Thyrotropin/physiology
19.
J Clin Endocrinol Metab ; 61(5): 846-50, 1985 Nov.
Article in English | MEDLINE | ID: mdl-3930551

ABSTRACT

In addition to stimulating GH release in normal subjects, GH-releasing hormone-40 (GHRH-40) stimulates GH secretion in some adults and children with GH deficiency. Recognizing that GHRH-40 may have potential as a therapeutic agent for the treatment of GH deficiency, we examined the effects of iv, sc, and intranasal (in) GHRH-40 administration on GH secretion and measured the plasma levels of immunoreactive GHRH achieved after the administration of the peptide via these different routes. Normal men were given vehicle or GHRH-40 iv (0.003, 0.01, 0.03, and 0.1 micrograms/kg; n = 10), sc (1, 3.3, and 10 micrograms/kg; n = 8), or in (3, 10, 30, and 100 micrograms/kg; n = 5). No subject had any symptoms after administration of vehicle or GHRH-40. During the 2-h period after iv administration of GHRH-40, the maximal increment in serum GH levels above basal (nanograms per ml; mean +/- SD) after the 0.1 micrograms/kg dose was 15.5 +/- 10.4 compared to 2.4 +/- 4.1 after vehicle (P = 0.0017). During the 3-h period after sc administration, when compared to the maximal increment in serum GH above basal after vehicle alone (10.2 +/- 12.9), the maximal increments above basal in serum GH were increased after both the 3.3 micrograms/kg (26.2 +/- 23.1; P = 0.022) and 10 micrograms/kg (63.6 +/- 53.5; P = 0.0003) doses. During the 3-h period after in administration, when compared to the maximal increment in serum GH above basal after vehicle alone (2.8 +/- 6.4), the maximal increments above basal in GH were higher after both the 30 micrograms/kg (18.5 +/- 10.4; P = 0.0053) and 100 micrograms/kg (21.7 +/- 8.1; P = 0.0028) doses. In addition, significant dose-response relationships were documented between the maximal increments above basal in serum GH and GHRH-40 administered by all routes. The mean (+/- SEM) peak plasma level of IR-GHRH (nanograms per ml) achieved after administration of 10 micrograms/kg GHRH-40, iv, as reported previously (66.6 +/- 17.6), was approximately 60- and 500-fold higher than the mean levels in the current study after administration of the same dose sc (1.11 +/- 0.39) or in (0.14 +/- 0.02), respectively. In summary, although GHRH-40 stimulates GH release when administered iv, sc, or in, significantly higher doses were required using the sc and in routes to achieve responses comparable to those obtained with iv administration.


Subject(s)
Growth Hormone-Releasing Hormone/administration & dosage , Growth Hormone/blood , Peptide Fragments/administration & dosage , Administration, Intranasal , Adult , Dose-Response Relationship, Drug , Humans , Injections, Intravenous , Injections, Subcutaneous , Male
20.
J Clin Endocrinol Metab ; 60(1): 144-9, 1985 Jan.
Article in English | MEDLINE | ID: mdl-3880562

ABSTRACT

We have tested the influence of a new calcium ion channel antagonist, diltiazem, on hypothalamic releasing hormone-stimulated secretion of LH and other anterior pituitary hormones in man. To this end, six normal men received a continuous infusion of GnRH (1 microgram/min) and TRH (2 micrograms/min) for 3 h under three different experimental conditions: 1) saline (control) infusion; 2) iv diltiazem (0.3 mg/kg bolus dose, and 0.002 mg/kg . min) infusion for 4 h beginning 1 h before releasing hormone injection; and 3) oral diltiazem (60 mg, every 6 h) administration for 1 week before pituitary stimulation. Blood was sampled at 10-min intervals for the subsequent immunoassay of LH, FSH, TSH, PRL, and GH concentrations and at hourly intervals for the assay of plasma diltiazem concentrations by high performance liquid chromatography. Despite sustained plasma diltiazem concentrations of 80-120 ng/ml during either iv or oral drug administration, the GnRH/TRH-stimulated release of LH, FSH, TSH, and PRL or the basal secretion of GH did not differ significantly from that during saline infusion. In contrast, when these subjects underwent the same infusion schedule using a structurally dissimilar calcium influx blocker, verapamil (5-mg bolus dose and 15 mg/h, continuous infusion), there was significant suppression of the delayed component of GnRH/TRH-stimulated LH release, with simultaneous enhancement of PRL secretion. We conclude that exogenously stimulated anterior pituitary hormone secretion in man exhibits differential susceptibility to the structurally discrete calcium entry blockers diltiazem and verapamil. Moreover, the differential influence of these two calcium ion channel antagonists on gonadotropes is distinct from that described in cardiac and smooth muscle cells.


Subject(s)
Calcium Channel Blockers/pharmacology , Gonadotropin-Releasing Hormone/pharmacology , Pituitary Hormones, Anterior/metabolism , Thyrotropin/pharmacology , Administration, Oral , Adult , Diltiazem/pharmacology , Humans , Infusions, Parenteral , Injections, Intravenous , Luteinizing Hormone/blood , Male , Time Factors , Verapamil/pharmacology
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