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Biomedical subjects

A Chico

Publications and source records attributed to A Chico.

At least 19 recordsLinked to original sources
PubMed2004

Influence of exogenous insulin on C-peptide levels in subjects with type 2 diabetes.

AIM: The aim of this study was to determine whether the influence of insulin therapy on fasting and stimulated C-peptide levels in type 2 diabetic subjects is due to plasma glucose reduction or a direct effect of exogenous insulin. METHODS: Plasma glucose and serum C-peptide levels were determined before and after IV injection of 1mg glucagon on three separate days in 21 type 2 diabetic subjects. Day 1: without pharmacological treatment and fasting plasma glucose > 11.1 mmol/L; day 2: fasting plasma glucose 4.4-7.8 mmol/L, 1h after withdrawing intravenous regular insulin infusion; day 3: fasting plasma glucose 4.4-7.8 mmol/L with bed-time NPH insulin. RESULTS: Fasting and glucagon stimulated C-peptide levels were higher on day 1 than days 2 and 3. Fasting, but not stimulated C-peptide levels, were lower on day 3 than day 2. These differences were not appeared when the percentage of C-peptide increment or the C-peptide/glucose ratio were compared in the three days. CONCLUSIONS: Blood glucose reduction instead of exogenous insulin is responsible for the C-peptide decrease during insulin therapy in type 2 diabetic subjects.

Aged↗
PubMed1999

Molecular pathology of multiple endocrine neoplasia type I: two novel germline mutations and updated classification of mutations affecting MEN1 gene.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined development of tumors in several endocrine glands and other tissues. The MEN1 gene was recently identified and isolated by positional cloning. This gene was screened in two unrelated MEN1 Spanish kindreds (with four affected members and seven asymptomatic members) using single-strand conformation polymorphism, DNA sequencing, and restriction enzyme analysis. Two novel germline mutations were identified: a missense in exon 2 (H139R) and a splice-site in intron 9 (1461-2A>C). These findings allowed us to identify the MEN1 carriers among the seven asymptomatic members analyzed. An updated review of the mutations and polymorphisms found in the analysis of the MEN1 gene is provided. The report of all germline mutations causing MEN1 and easy access to this updated information are both of special diagnostic interest, because this greatly facilitates the task of attributing the disorder to a specific mutation found in a given MEN1 family. This is especially helpful in the critical differentiation of missense mutations from nonsynonymous polymorphisms that fit the pattern of segregation of the disease, but do not cause it.

Adolescent↗
PubMed1998

Reversible endocrine dysfunction and pituitary stalk enlargement.

We report 4 patients (3 of which were children) with diabetes insipidus and different degrees of hypopituitarism in whom a pituitary stalk enlargement was disclosed on imaging techniques, and in whom radiological and functional recovery was observed during follow-up. Pituitary substitution therapy with desmopressin, thyroxine, hydrocortisone, growth hormone and/or oral contraceptives was prescribed. During follow-up, regression of the stalk lesion was seen which was spontaneous in 2 cases, following a short course of corticosteroids in another and an empirical trial of tuberculostatic drugs in the fourth. A partial recovery of pituitary function was also observed. These cases illustrate that pituitary stalk enlargement and associated hypopituitarism may be reversible; however, this morphological and functional recovery has rarely been described in adults and has not been previously reported in children.

Adolescent↗
PubMed1998

Plasma homocysteine is related to albumin excretion rate in patients with diabetes mellitus: a new link between diabetic nephropathy and cardiovascular disease?

The high risk of cardiovascular disease in patients with diabetes mellitus, particularly in those with nephropathy, is not completely explained by classical risk factors. A high plasma homocysteine concentration is an independent risk factor for cardiovascular disease but information on its association with diabetes is limited. Fasting homocysteine concentrations were measured in the plasma of 165 diabetic patients (75 with insulin-dependent [IDDM]; 90 with non-insulin-dependent diabetes [NIDDM]) and 56 non-diabetic control subjects. Other measurements included the prevalence of diabetic complications, glycaemic control, lipid and lipoprotein levels, vitamin status and renal function tests. Patients with NIDDM had higher homocysteine levels than control subjects, whereas IDDM patients did not (9.2 +/- 4.5 vs 7.7 +/- 2 micromol/l, p < 0.01; and 7.0 +/- 3 vs 7.4 +/- 2 micromol/l, NS). Univariate correlations and multiple regression analysis showed albumin excretion rate to be the parameter with the strongest independent association with homocysteine. Patients with both types of diabetes and nephropathy had higher plasma homocysteine concentrations than those without nephropathy. Increases of homocysteine in plasma were related to increases in the severity of the nephropathy. Fasting hyperhomocysteinaemia was considered as the mean of the plasma homocysteine for all control subjects (7.5 +/- 2.1 micromol/l) + 2 SD (cut-off = 11.7 micromol/l). Nephropathy was present in 80 % of diabetic patients with fasting hyperhomocysteinaemia. In conclusion, increases in fasting homocysteine in diabetic patients are associated with increased albumin excretion rate, especially in those with NIDDM, thus providing a potential new link between microalbuminuria, diabetic nephropathy and cardiovascular disease.

Adult↗
PubMed1998

Use of somatostatin analogue scintigraphy in the localization of recurrent medullary thyroid carcinoma.

Detection of recurrence of medullary thyroid carcinoma (MTC) remains a diagnostic problem. Increased serum tumour marker levels frequently indicate recurrence while conventional imaging techniques (CIT) are non-diagnostic. In this study, we performed indium-111 octreotide scintigraphy and CIT in a series of 20 patients with MTC presenting with elevated serum tumour markers after surgery. 111In-octreotide whole-body studies detected 15 pathological uptake foci in 11 of the 20 patients studied and CIT detected 17 lesions in 11 of the 20 patients. Ten patients underwent reoperation, five of them with positive 111In-octreotide scintigraphy and CIT and two with positive isotopic exploration and negative CIT. Surgical findings demonstrated that the results of isotopic study and CIT had been false-positive for MTC in one case (sarcoidosis). The six patients with true-positive 111In-octreotide studies had significantly higher basal calcitonin (CT) and carcinoembryonic antigen (CEA) levels than the patients with negative isotopic studies. The expression of somatostatin receptor (SSTR) subtypes by PC-PCR could be investigated in four cases with a positive isotopic study. Among the three cases with a true-positive study, SSTR2, the SSTR subtype that preferentially binds to the somatostatin analogue octreotide, was detected in two, SSTR5 was demonstrated in the three, and SSTR3 was detected in one. No subtype of SSTR was detected in the case with a final diagnosis of sarcoidosis. We conclude that 111In-octreotide has limited sensitivity in detecting recurrence in patients with MTC, although its sensitivity may improve with high serum CT levels. This radionuclide imaging technique should be employed when conventional imaging techniques are negative or inconclusive or when the presence of somatostatin receptors may provide the basis for treatment with somatostatin analogues.

Adult↗
PubMed1998

Clinical forms of presentation and evolution of diffuse sclerosing variant of papillary carcinoma and insular variant of follicular carcinoma of the thyroid.

We investigated whether the diffuse sclerosing variant of papillary carcinoma (diffuse sclerosing PC) and insular carcinoma (IC), two different subforms of differentiated carcinoma of the thyroid gland, have different clinical behaviors and prognosis in order to select appropriate therapy. The characteristics of clinical presentation, and outcome after therapy were evaluated in a series of 113 patients (18 males and 95 females) with differentiated thyroid carcinoma treated with the same protocol, of which 7 had diffuse sclerosing PC and 6 had IC; within this series, patients with diffuse sclerosing PC and IC were compared with 76 cases of papillary carcinoma (PC) and 24 cases of follicular carcinoma (FC), respectively. Diffuse sclerosing PC patients were younger (23+/-9 vs. 38+/-16 years) and had a higher degree of lymphatic metastases at diagnosis (100%) than patients with PC (47%). Five of 7 patients with diffuse sclerosing PC were alive and without evidence of disease compared to 34 of 76 patients with PC at follow-up (6.4+/-5.1 and 7.9+/-7 years, respectively). No prognostic differences were found between them. IC showed a more advanced stage of disease at diagnosis and a more aggressive clinical course with a higher percent of metastases and mortality than patients with FC at follow-up (1 patient died and 5 were alive with persistent disease at 4.8+/-3.7 years for IC; 22 were alive, 13 of them with persistent disease; and 2 died at 8.4+/-5.3 years for FC). We conclude that patients with diffuse sclerosing PC do not require a different treatment than that given to PC patients, while in contrast, IC cases need a more aggressive therapeutic approach.

Adenocarcinoma, Follicular↗
PubMed1998

Somatostatin and somatostatin receptor subtype gene expression in medullary thyroid carcinoma.

The possible existence of an autocrine/paracrine role for SRIF in normal and neoplastic thyroid parafollicular C cells has supported the use of SRIF analogues in the treatment of patients with medullary thyroid carcinoma (MTC). In this study, we have investigated the expression of SRIF by immunohistochemistry and RT-PCR, and the expression of SRIF receptor (SSTR) subtypes by RT-PCR, in a series of 14 MTCs. SRIF messenger RNA was detected in all cases, although immunoreactive cells were only identified in 8. SSTR messenger RNA was present in 12 out of the 14 tumors. Expression of more than 1 SSTR subtype was detected in 10 tumors. SSTR2, the subtype that preferentially binds to the SRIF analogue octreotide, was the subtype most frequently detected, whereas SSTR4 was not detected in any case. These results confirm the frequent expression of both SRIF and its receptors in MTC. The presence of different combinations of SSTR subtypes in a given patient may explain the variable clinical response to SRIF analogues and may promote the search for more selective drugs with different affinities to the various receptor subtypes.

Adolescent↗
PubMed1997

Molecular diagnosis of von Hippel-Lindau disease in a kindred with a predominance of familial phaeochromocytoma.

OBJECTIVE: To study the presence of germline mutations in the von Hippel-Lindau gene (vhl) in a kindred with a predominance of familial phaeochromocytoma in order to confirm the diagnosis of von Hippel-Lindau disease (VHLD) as well as to identify asymptomatic members. DESIGN: DNA extracted from peripheral blood was amplified by the polymerase chain reaction using oligonucleotide primers corresponding to exon 3 of the vhl gene. Specific mutations in codon 238 were screened by restriction endonuclease digestion of PCR products with Msp I. The results were confirmed by DNA sequence analysis. PATIENTS: Two generations of a family consisting of 15 individuals were studied. RESULTS: A germline missense point mutation at codon 238 of the vhl gene (CGG-->TGG; Arg-->Trp) was detected in all patients with phaeochromocytoma and in only one of the asymptomatic family members. CONCLUSION: Mutational analysis of the vhl gene in patients with familial phaeochromocytoma may permit specific diagnosis of von Hippel-Lindau disease, and is a good method for the identification of asymptomatic individuals at risk of von Hippel-Lindau disease.

Adolescent↗
PubMed1996

Bronchial carcinoid tumor presenting as a thyroid nodule: an unusual clinical manifestation.

Although rare, carcinoid tumors may present as thyroid metastatic nodules. We describe two patients with an undiagnosed bronchial carcinoid tumor, who presented as a thyroid nodule. Pathological examination of these nodules was diagnostic. Chemotherapy was indicated despite the dissemination of the tumors. The patients have an excellent quality of life. They are asymptomatic and alive, 18 and 24 months after diagnosis, respectively. In one case, chemotherapy obtained an important reduction in the size of the tumoral lesions but the other case showed no regression. Octreotide (SMS 201-995) was used in the case with carcinoid syndrome, with an excellent response.

Adult↗
PubMed1996

Lipoprotein(a) concentrations and non-insulin-dependent diabetes mellitus: relationship to glycaemic control and diabetic complications.

UNLABELLED: The aim of our study was to determine the lipoprotein(a) (Lp(a)) levels in patients with non-insulin-dependent diabetes mellitus (NIDDM) and to evaluate Lp(a) concentrations in relation to glycaemic control and diabetic complications. We evaluate in a cross-sectional study a total of 103 NIDDM patients (52 males and 51 females; mean age of 62.5 years; mean of diabetes duration: 12 years) referred to our hospital because of poor glycaemic control, and a group of 108 non-diabetic subjects (57 males and 51 females). RESULTS: mean Lp(a) concentration did not significantly differ between NIDDM patients and non-diabetic subjects (11.1 +/- 14 vs. 16.2 +/- 14 mg/dl). The distribution of Lp(a) levels was highly skewed towards the lower levels in both groups, being over 30 mg/dl in only 6% of NIDDM patients and 12% of controls. Patients with Lp(a) levels over 10 mg/dl had lower haemoglobin Alc (HbA1c) than patients with Lp(a) levels over 10 mg/dl (8.5% vs. 10.4%; P < 0.01). Lp(a) concentration was positively correlated with body mass index (BMI) (P < 0.05) and HbA1c (P < 0.05). No association was found between Lp(a) and sex, age, other lipidic parameters, microalbuminuria, type of treatment and presence of cardiovascular disease. These findings may suggest that glycaemic control could have a modulatory role on Lp(a) concentration in NIDDM patients. In this study, diabetic complications did not seem to be associated with higher Lp(a) concentrations.

Aged↗
PubMed1996

Cushing's disease and pregnancy: report of six cases.

We describe six pregnancies in five patients with Cushing's disease --four had undergone transsphenoidal surgery, with improvement but no cure of their hypercortisolism; the other woman became pregnant during initial work up. At conception, none of the patients were receiving specific treatment for hypercortisolism. Mean free urinary cortisol (FUC) prior to pregnancy was 430 nmol/24 h (normal range: 51-280). In two patients, FUC throughout pregnancy increased significantly, but no clinical progression was observed. FUC measured in 20 healthy pregnant women was found to rise above the normal non-pregnant range ( < 280 nmol/24 h) in the second (mean +/- 2 S.D. = 463 +/- 256 nmol/24 h; P < 0.01) and third trimester (424 +/- 210 nmol/24 h; P < 0.05). However, in the Cushing patients values were higher. Two pregnancies ended in spontaneous abortions, one resulted in an ectopic pregnancy, and the remaining three were followed to term of which one developed third trimester gestational diabetes, and her baby developed neonatal sepsis which resolved uneventfully. We conclude that despite high abortion and ectopic pregnancy rates, a remarkably uneventful and uncomplicated outcome with no clinical progression of cushingoid symptoms, was observed in two of the three pregnancies followed to term, despite significant increases in FUC.

Adrenocorticotropic Hormone↗
PubMed1996

Ultrastructural study of chondrocytes from fibrillated and non-fibrillated human osteoarthritic cartilage.

Knee articular cartilage samples obtained by arthroscopy from ten patients with well defined knee osteoarthritis (OA) were studied by light and transmission electron microscopy. The morphological phenotype of cells from fibrillated and non-fibrillated regions of OA cartilage was characterized. Three different cell sub-populations were identified. Type 1 cells were found in the superficial and upper middle zones and comprised single chondrocytes and cells organized in aggregates or "clones' that showed a typical chondrocyte phenotype. Type 2 cells displayed a secretory phenotype. Type 3 cells comprised chondrocytes undergoing a degenerative process and were distributed throughout all zones of the cartilage. Changes in the cytoskeletal arrangement, presence of abundant filopodia, peripheral localization of centrioles, and presence of primary cilia were found in many chondrocytes suggesting that they are active motile cells. No mitotic figures were found in this study. Morphometrical analysis was performed to determine the total number of cells and the number of chondrocytes per lacuna in the superficial and upper middle zones of fibrillated and non-fibrillated OA cartilage. There were no statistically significant differences in the total number of cells. In contrast, fibrillated OA cartilage contained a statistically significantly higher percentage of lacunae containing four of more chondrocytes than non-fibrillated OA cartilage samples. The absence of mitotic figures and the presence of motile elements in many chondrocytes raise the possibility that cell aggregates or "clones' in damaged OA cartilage originate by an active process of cell migration rather than by cellular division.

Aged↗
PubMed1996

Variability in the cell phenotype of aggregates or "clones" of human osteoarthritic cartilage. A case report.

Human samples of articular cartilage from the knee of a clinically classified osteoarthritic patient, assessed by arthroscopy as part of the surgical treatment was studied by light and transmission electron microscopy. This particular case differed from others already reported in the variability of cell phenotype within the aggregates or "clones" frequently present in the osteoarthritic cartilage. The most common morphology of "clonal" cells forming the aggregates were large and rounded with an euchromatic nucleus. The cytoplasm was characterized by the presence of alternately clear and dense sites. At the ultrastructural level it was seen that the clear sites were formed by disrupted intermediates filaments and small particles, and that the dense sites were constituted by the segregation of different organelles of the chondrocytes. In addition, there were atypical aggregates composed only by secretory cells or by degenerating chondrocytes. Furthermore, a complex structure consisting of a very large cell inside a giant lacunae delimited by electron-dense material with small vesicles is described as a novel finding. The variability in the chondrocyte phenotype of the aggregates described here could be an indication of a better prognosis; nevertheless, the follow-up of the evolution of this patient is needed in order to know the final outcome.

Cartilage, Articular↗
PubMed1995

A gonadotrophin dependent stromal luteoma: a rare cause of post-menopausal virilization.

A stromal luteoma is an uncommon ovarian tumour in post-menopausal women, which presents rarely with hyperandrogenism and virilization. We present the case of a 64-year-old woman referred for evaluation of virilization which had developed over 5 years. Testosterone, FSH and LH were markedly inhibited following the administration of a GnRH analogue, suggesting a gonadotrophin dependent, testosterone secreting ovarian tumour, which could not be localized with imaging techniques. Surgery revealed normal sized ovaries with no apparent lesions, but microscopic examination showed a small stromal luteoma in the right ovary and severe stromal hyperthecosis in the adjacent and contralateral ovarian stroma. We conclude that stromal luteoma is an uncommon cause of virilization in post-menopausal women. This case illustrates, to our knowledge for the first time, that a stromal luteoma is not autonomous but is gonadotrophin dependent.

Depression, Chemical↗
PubMedDate not supplied

A novel germline mutation in exon 5 of the multiple endocrine neoplasia type 1 gene.

The autosomal dominant multiple endocrine neoplasia type 1 (MEN1) syndrome is characterized by neoplasia of parathyroids, anterior pituitary, and gastrointestinal and pancreatic neuroendocrine tissues. Recently the gene responsible for the MEN1 syndrome has been identified on chromosome region 11q13. Most of the described mutations are nucleotide substitutions and small deletions affecting exons 2 and 3, causing protein truncation. Only one mutation in exon 5 has been found, and this corresponds to a MEN1 sporadic case. Small insertions are also rare. We studied a MENI family composed of five members, two of whom were clinically affected. We found a new germline 1 basepair insertional mutation affecting the exon 5 of the MEN1 gene in the two members affected in this MEN1 family.

Adult↗