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Biomedical subjects

F Gomez

Publications and source records attributed to F Gomez.

At least 55 records · Page 3Linked to original sources
PubMed1999

Warning! Nearby construction can profoundly affect your experiments.

This is meant to alert people to potentially major effects of construction projects on research results. Because we study the effects of stress on regulation of ACTH and corticosterone secretion and of serotonin receptors and stress on energy balance, we serve as an early warning system when things go awry. Most of our experiments include taking daily, or twice daily, measurements of rat or mouse weights and food intake as well as stress hormone levels. We are highly sensitized to environmental disruption and we've shown previously the effects of construction on stress hormones (1). However, we did not anticipate the change and disruption in energy balance that may occur in response to environmental perturbation. We provide two examples of these, below.

Animals↗
PubMed1998

The International Prognostic Index correlates to survival in patients with aggressive lymphoma in relapse: analysis of the PARMA trial. Parma Group.

The objectives of the present study were to investigate the prognostic value of the International Prognostic Index (IPI) at relapse in the 215 patients with intermediate- or high-grade non-Hodgkin's lymphoma (NHL) included in the PARMA trial. The IPI at relapse was available in 204 (95%) of these patients. Response rates to 2 courses of DHAP were 77%, 54%, 55%, and 42% in patients with an IPI of 0, 1, 2 and 3, respectively (P <.02), whereas complete response (CR) rates were 33%, 29%, 20%, and 0% in the same groups of patients (P <.03). With a median follow-up period of 79 months, overall survival (OS) at 5 years was 46%, 25%, 25%, and 11% in these four groups (P <.001). One hundred nine patients responding to 2 courses of DHAP were randomized to receive either BEAC (carmustine, etoposide, cytarabine, cyclophosphamide and mesna) followed by autologous bone marrow transplantation (ABMT) or 4 additional courses of DHAP: IPI at relapse was found highly correlated to OS in patients treated in the DHAP arm (5-year OS: 48%, 21%, 33%, and 0% for IPI 0, 1, 2, and 3, respectively; P =.006), but not in the BEAC arm (5-year OS: 51%, 47%, 50%, and 50% for IPI 0, 1, 2, and 3, respectively; P =.90). OS was significantly superior in the BEAC arm as compared with the DHAP arm in patients with an IPI >0 (P <.05), but not in patients with an IPI of 0. In conclusion, these results show that IPI correlates to response and overall survival in patients with aggressive NHL in relapse and enables us to identify patients with a significantly different outcome among those treated with conventional chemotherapy alone.

Adolescent↗
PubMed1998

Immunolocalization of neuropeptide Y in human pituitary tumours.

Neuropeptide Y (NPY) gene is expressed in human pituitary gland where its function is partially elucidated. NPY could act as a neuroendocrine modulator within this gland. This study was undertaken to assess whether NPY expression is correlated to various pathological situations. Using a highly specific anti-NPY monoclonal antibody, immunohistochemistry analysis was performed in surgically removed pituitary glands. The study included biopsies from 112 human pituitary adenomas, 12 hyperplastic glands and normal anterior pituitary tissues in 34 cases. NPY is immunodetected in 33% of all adenomas, 25% hyperplastic glands and 12% of non-tumoral pituitary gland. NPY expression was significantly higher in adenomas compared to the normal gland. However, no correlation was observed between NPY content and the type of hormonal secretion, sex, age and the status of tumour proliferating potential.

Adenoma↗
PubMed1998

[Social representations of male sterilization. Vasectomy as viewed by professional counselors at the Men's Clinic in Bogotá,Colombia]

Vasectomy service providers at the Clínica del Hombre (Men's Clinic) in Bogotá, Colombia, construct their representations concerning male sterilization on the basis of biomedical discourse, their interaction with clinic users, and their own life experiences. During provision of such services, the counselors are the health professionals who have the closest contact with these clients of the clinic. Counselors are in charge of exploring their motivations in requesting the service, in addition to providing information allowing them to take a calm, sound decision. They also directly filter demand based on their experience, knowledge, and skills, in permanent negotiation between institutional criteria (number of children and gap between them, client's age, steadiness of couple's relationship, and conviction concerning the decision), and their perception and assessment of the client. An analysis of the counselors' representations of decision-making as pertaining to vasectomy indicates that it is a relatively simple and harmless procedure as well as a liberating option in terms of family planning.

Journal Article↗
PubMed1998

Treatment with progesterone analogues decreases macrophage Fcgamma receptors expression.

Macrophage Fcgamma receptors (FcgammaRs) are critical for host defense against infection and have an important role in immune cytopenias. Modulation of macrophage FcgammaRs expression is a potential therapeutic approach to immune disorders. Glucocorticoids and synthetic progesterone analogues decrease macrophage FcgammaRs expression. We assessed the effect of treatment with commonly employed progestins on the expression of macrophage FcgammaRs using an experimental model in the guinea pig. Eight clinically available progesterones, medroxyprogesterone acetate (P3), megestrol acetate (P4), medrogestone (P5), alylestrenol (P6), linestrenol (P7), didrogesterone (P8), norethisterone (P9), and gestonorone caproate (P10) and two endogenous progesterones, progesterone (P1) and 17 alpha-hydroxyprogesterone (P2), were studied. Following in vivo treatment of guinea pigs, we determined the clearance of IgG-sensitized erythrocytes in vivo, the binding of IgG-sensitized erythrocytes by isolated splenic macrophages, and splenic macrophage Fcgamma receptor cell surface expression. All progesterones impaired the clearance of IgG-sensitized erythrocytes by decreasing splenic macrophage Fcgamma receptor expression. P5, P6, P7, and P8 were less effective. Flow cytometry and fluorescence microscopy with monoclonal antibodies demonstrated that progesterones decreased the cell surface expression of FcgammaR2 more than that of FcgammaR1,2. Clinically employed progestins impair the clearance of IgG-coated cells by decreasing splenic macrophage FcgammaRs expression. Thus, progesterones are candidate drugs for the treatment of immune disorders.

Animals↗
PubMed1998

Ectopic ACTH Cushing's syndrome: V3 vasopressin receptor but not CRH receptor gene expression in a pulmonary carcinoid tumor.

In the etiological diagnosis of ACTH-dependent Cushing's syndrome, it may be difficult to distinguish pituitary disease from ectopic ACTH production, specially when this is due to a benign neuroendocrine tumor. We describe a patient with partial dexamethasone suppression consistent with Cushing's disease, an absent response to CRH suggesting ectopic ACTH production and an atypical, apparent circadian rhythm. Bilateral cavernous sinus catheterization suggested a nonpituitary source of ACTH and, in the search of an ectopic tumor, somatostatin receptor scintigraphy, abdominal CT scan, and duodenopancreatic endoscopic echography were performed and failed to reveal any abnormality. Thoracic CT scan disclosed a tiny right lung nodule that showed a definite tracer uptake on MIBG scintigraphy. After resection, the nodule proved to be an 8-mm typical pulmonary carcinoid, with positive immunostaining for the classical neuroendocrine markers and for ACTH, and showing tissue expression of the POMC gene. However, the CRH receptor gene was not expressed, explaining the absent CRH response in vivo, whereas the V3 vasopressin receptor gene was expressed in the tumor tissue. The latter feature appears to be characteristic of benign carcinoids and may contribute to explaining the CRH-independent circadian rhythm observed in this case.

ACTH Syndrome, Ectopic↗
PubMed1998

Time to relapse has prognostic value in patients with aggressive lymphoma enrolled onto the Parma trial.

PURPOSE: The purpose of this study was to investigate the prognostic value of time to relapse in 188 adult patients with intermediate- or high-grade non-Hodgkin's lymphoma (NHL) included on the Parma trial at the time of their first relapse. PATIENTS AND METHODS: The median follow-up of these patients is 102 months after registration onto the Parma study. Time to relapse was calculated from initial diagnosis, and a cutoff of 12 months was used to separate 77 patients defined as early relapse from 111 patients defined as late relapse. RESULTS: Patients with early and late relapses had significantly different overall response rates to salvage therapy with two courses of dexamethasone, high-dose cytarabine, and cisplatin (DHAP; 40% v 69%; P=.00007) and different 8-year survival rates (13% v 29%; P=.00001). Features at relapse with a negative prognostic value in univariate analysis were higher than normal lactic dehydrogenase (LDH) levels, tumor size greater than 5 cm, Ann Arbor stages III to IV, and Karnofsky score less than 80%. Therefore, multivariate analyses were performed. Time to relapse (P=.001) and LDH levels at relapse (P=.003) had independent prognostic value, whereas tumor size did not reach statistical significance in the logistic model that predicted overall response after two courses of DHAP. The study of prognostic factors for overall survival (OS) and progression-free survival (PFS) confirmed the prognostic value of time to relapse (P < .0001 for OS and P=.005 for PFS) independent of response or treatment after two courses of DHAP. CONCLUSION: Time to relapse may be used to stratify patients at time of first relapse of intermediate to high-grade non-Hodgkin's lymphoma.

Adult↗
PubMed1998

Subcutaneous interleukin-2, interferon alfa-2a, and continuous infusion of fluorouracil in metastatic renal cell carcinoma: a multicenter phase II trial. Groupe Français d'Immunothérapie.

PURPOSE: A phase II trial was designed to determine the efficacy and the tolerance of interleukin-2 (IL-2), interferon alfa-2a (IFNalpha), and fluorouracil (5-FU) in patients with metastatic renal cell carcinoma. PATIENTS AND METHODS: One hundred eleven patients were included. Patients received subcutaneous IL-2 9 x 10(6) IU daily for 6 days and IFNalpha 6 x 10(6) IU on days 1, 3, and 5 every other week for 8 weeks. 5-FU was administered through a continuous infusion at 600 mg/m2 for 5 consecutive days for 1 week every 4 weeks. RESULTS: The response rate was 1.8% (95% confidence interval [CI], 0% to 4.3%) with only two partial responses (PRs). Toxicity was moderate with 3.6% grade 4 events and two deaths related to treatment. CONCLUSION: This regimen of IL-2, IFNalpha, and 5-FU in patients with metastatic renal cell carcinoma was ineffective. The results raise the question of the dose and schedule of subcutaneous cytokines that must be used in metastatic renal carcinoma.

Adult↗
PubMed1998

MMPI-2 and MMPI-A research with U.S. Latinos: a bibliography.

This bibliography presents a comprehensive listing of all research conducted on U.S. Latinos, including Puerto Ricans, with the MMPI-2 and MMPI-A beginning in 1989. A total of 52 studies and 6 additional resources are listed. Researchers and clinicians could use this bibliography for the culturally appropriate application of the MMPI-2/MMPI-A with this growing population.

Hispanic or Latino↗
PubMed1998

Traumatic pseudoaneurysm of the axillary artery following anterior dislocation of the shoulder. Case report.

Vascular complications are rare in cases of simple anterior dislocation of the shoulder but the axillary artery or its branches may be damaged. Very few cases are found in the literature reporting false aneurysms of axillary artery secondary to blunt trauma to the shoulder. A case of pseudoaneurysm of the axillary artery in a 75-year-old woman is reported. Diagnosis was suspected because large pectoral haematoma with haemodynamic instability appeared a few hours later after manual reduction of the dislocation. The pseudoaneurysm was confirmed with selective angiography of the axillary artery. Arteriography should be performed whenever vascular injury is suspected. Delayed recognition of these lesions may lead to permanent neurologic deficits despite adequate vascular repair of the axillary artery. A coordinated vascular and orthopaedic approach and prompt surgical treatment may assure full upper limb function. Although endovascular treatment of these lesions could seem attractive, we prefer to use open surgical techniques because they allow us to treat frequent concomitant injuries and perform decompression of the axillar fossa because of the large haematoma.

Accidental Falls↗
PubMed1997

Arginine vasopressin (AVP) depletion in neurons of the suprachiasmatic nuclei affects the AVP content of the paraventricular neurons and stimulates adrenocorticotrophic hormone release.

Arginine vasopressin (AVP) produced in the hypothalamic suprachiasmatic nuclei (SCN) plays a role in establishing neuroendocrine rhythms and, in particular, in regulating the corticotrope axis rhythm. It has recently been shown that AVP from SCN inhibits corticosteroid release. In order to investigate the influence of suprachiasmatic AVP on the different peptidergic systems through the hypothalamus, SCN neurons containing AVP were functionally lesioned by using toxins associated with a cytotoxic monoclonal antibody (MAb) raised against AVP. Six days later, the AVP contents and AVP mRNA were measured in different hypothalamic and extrahypothalamic sites. Adrenocorticotrophic hormone (ACTH) concentration was also measured in plasma. Microinjection of the AVP-MAb/toxin mixture into SCN brought about a significant decrease in the AVP expression in SCN. This is demonstrated by the decrease in the AVP immunoreactive content (24%, P < 0.01) and the decrease of AVP hybridized mRNA (33%, P < 0.01). This points to the efficiency of the microinjection in decreasing the production of AVP in the injection area. Modifications of the AVP contents in the two subdivisions of the hypothalamic paraventricular nucleus (PVN) were also observed. AVP contents decreased in the parvocellular subdivision (pPVN); this is coherent with the AVP depletion in SCN since pPVN is the major site of the SCN hypothalamic efferences. AVP content and AVP mRNA increased in the magnocellular subdivision (mPVN); this also confirms the difference in AVP synthesis regulation according to the PVN subdivisions. The microinjection did not modify AVP expression in supraoptic nuclei or oxytocin (OT) immunoreactive content in the main hypothalamic OT containing sites. Plasma ACTH values were double (P < 0.02) the values measured under non-specific IgG treatment 10 hr after lights on. This probably resulted from the stimulation of the hypothalamo-pituitary-adrenal system since corticotrophin-releasing hormone (CRH) mRNA increased simultaneously by 24% (P < 0.05) in the PVN and the immunoreactive CRH content of the median eminence significantly decreased (26%, P < 0.05). Overall, our data confirm that AVP produced in the SCN inhibits the CRH-adrenocorticotrope axis in normal conditions, probably because of SCN projections of AVP neurons on the PVN.

Adrenocorticotropic Hormone↗
PubMed1997

In vivo and in vitro effects of somatostatin and insulin on glucagon release in a human glucagonoma.

Inhibition of pancreatic glucagon secretion has been reported to be mediated by glucose, insulin and somatostatin. As no human pancreatic alpha-cell lines are available to study in vitro the relative importance of insulin and glucose in the control of pancreatic glucagon release, we investigated a patient presenting with a malignant glucagonoma who underwent surgical resection of the tumour. Functional somatostatin receptors were present as octreotide administration decreased basal glucagon and insulin secretion by 52 and 74%, respectively. The removed tumour was immunohistochemically positive for glucagon, chromogranin A and pancreatic polypeptide but negative for insulin, gastrin and somatostatin. The glucagonoma cells were also isolated and cultured in vitro. Incubation experiments revealed that change from high (10 mM) to low (1 mM) glucose concentration was unable to stimulate glucagon secretion. A dose-dependent inhibition of glucagon release by insulin was however, observed at low glucose concentration. These findings demonstrate that insulin could inhibit glucagon secretion in vitro in the absence of elevated glucose concentrations. These data suggest, as observed in vivo and in vitro in several animal studies, that glucopenia-induced glucagon secretion in humans is not mediated by a direct effect of low glucose on alpha-cells but possibly by a reduction of insulin-mediated alpha-cell suppression and/or an indirect neuronal stimulation of glucagon release.

Chromogranin A↗
PubMed1997

Insulinoma associated with a case of multiple endocrine neoplasia type I: Functional somatostatin receptors and abnormal glucose-induced insulin secretion.

A sporadic case of multiple endocrine neoplasia type I with coexisting insulinoma and hyperparathyroidism was investigated in vivo and in vitro. The insulinoma was localized by somatostatin receptor scintigraphy and these receptors were functionally active. Octreotide administration decreased the basal insulin and glucagon secretion by 90 and 46%, respectively. Immunocytochemistry of the insulinoma tissue was positive for insulin, chromogranin A and neuropeptide Y. The insulinoma cells were also isolated and cultured in vitro. Incubation experiments revealed that a low glucose concentration (1 mmol/l) was sufficient to increase cytosolic free calcium and to produce a maximal glucose-induced insulin release. Northern blot analysis of RNA obtained from the tumor showed a high abundance of the low Km glucose transporter GLUT1 but no transcript for the high Km glucose transporter GLUT2. The abnormal distribution of glucose transporters probably relates to the abnormal glucose sensing of insulinoma cells, and explains their sustained insulin secretion at low glucose concentrations. Whether these abnormalities share a pathogenetic link with the presence of functionally active somatostatin receptors remains to be elucidated.

Actins↗
PubMed1996

Fawn-hooded rats show enhanced active behaviour in the forced swimming test, with no evidence for pituitary-adrenal axis hyperactivity.

Fawn-hooded (FH) rats have been reported to have high basal corticosterone levels that can be normalized by antidepressant administration. In the present work, some behavioural and endocrine aspects were compared in FH and Sprague-Dawley (SD) rats. No interstrain differences in basal corticosterone levels or response to acute tail-cut stress were observed either in the morning or in the evening. Relative adrenal weight was lower in FH than SD, and relative thymus weight was, accordingly, higher in FH than SD rats. FH rats were hyperactive in the holeboard and showed behaviour similar to that of SD in the plus-maze. In contrast, FH rats showed greater levels of active behaviour (struggling) and lower levels of immobility than SD rats in the forced swimming test (FST). After desipramine (DMI) administration the differences between the two strains in the FST were more marked than in vehicle-treated animals. These results indicate that FH rats show no signs of pituitary-adrenal (PA) hyperactivity or depression-like behaviour, and therefore they are not an appropriate animal model of depression.

Adrenal Glands↗
PubMed1996

Normogonadotropic primary amenorrhea in a growth hormone-deficient woman with ectopic posterior pituitary: gonadotropin pulsatility and follicle-stimulating hormone bioactivity.

We studied the gonadotropic function in a 25-year-old woman suffering from congenital GH deficiency, complaining of primary amenorrhea and wishing to become pregnant. She disclosed a hypoplasic anterior pituitary within a small sella turcica and an ectopic posterior pituitary lobe located below the median eminence. Immunoreactive LH and FSH plasma levels were normal, basal and in response to a GnRH iv bolus but estradiol was low. LH pulse frequency was elevated and FSH bioactivity was low in a granulosa cell aromatase bioassay. Pulsatile administration of iv GnRH at a slower, normal pace, failed to induce ovulation or to increase FSH bioactivity, with or without concomitant GH replacement. However treatment with exogenous im gonadotropins, when preceeded by GH replacement, succeeded in inducing mature oocytes and pregnancy. We concluded that the hypogonadism observed in this patient was due to rapid GnRH pulsatility and poor biological activity of endogenous FSH.

Adult↗
PubMed1996

Neuropeptide Y secretion from a human insulinoma.

Neuropeptide Y (NPY) is a 36 aminoacid peptide known to inhibit glucose-stimulated insulin secretion. NPY has been shown to be synthesized and secreted by rat islets of Langerhans. More recently, we described the presence on NPY within human islets of Langerhans and in several pancreatic endocrine tumors. In this report, we describe the case of a patient presenting with an insulinoma who underwent the surgical resection of the tumor and was studied in vivo and in vitro for NPY production. Using a highly specific and sensitive two-site amplified enzyme-linked immunosorbent assay, we detected high plasma NPY levels in the patient prior to the surgical resection of the tumor which returned to normal after surgery. NPY was secreted from the tumor when kept in primary cell culture. Furthermore, immunohistochemistry of the insulinoma revealed the presence of NPY and its C-flanking peptide together with insulin, chromogranin and neuron specific enolase. It is concluded that elevated circulating NPY levels observed in this patient with an insulinoma reflected in vivo secretion by the tumor and it is hypothesized that NPY could potentially be used as an endocrine marker in patients with suspected insulinoma.

Aged↗