PubMed Health⌕ Search

Biomedical subjects

Miguel F Herrera

Publications and source records attributed to Miguel F Herrera.

At least 19 recordsLinked to original sources
PubMed2006

Differential RNA expression profile by cDNA microarray in sporadic primary hyperparathyroidism (pHPT): primary parathyroid hyperplasia versus adenoma.

BACKGROUND: Differential diagnosis between adenoma and hyperplasia in primary hyperparathyroidism (pHPT) remains a dilemma. The aim of this study was to assess differences in transcriptional genomic expression profiles between sporadic (nonfamilial) parathyroid hyperplasia (SPH), adenoma, and normal tissue. METHODS: Parathyroid tissue from 12 patients with parathyroid adenoma, 3 with SPH, and 2 with normal glands was selected for analysis. Histopathology was reviewed in all cases, and all patients with adenomas presented normocalcemia for a minimum of 6 months after one gland resection. Hybridizations were performed in a microarray containing 19,968 human cDNA clones including contiguous replicates. Direct comparisons were performed with reverse labeling for every different pooled sample entity. Expression levels were analyzed using the SAM, SMA, LIMMA, Cluster, and PAM packages in the R environment for statistical computing. RESULTS: There were significant statistical differences between SPH and adenomas. In the direct comparison, a total of 200 genes showed differential expression (P < 0.03): 61 genes were upregulated (> 1.65-fold increase) and 139 were downregulated (> 1.58-fold decrease) with a B value > 4.68 (99.08% probability of real differential expression). When SPH was compared to normal parathyroid tissue, 50 genes were differentially expressed: 42 were upregulated (> 1.89) and 8 were downregulated (> 1.7) with a B > 4.26 (98.6% probability of real differential expression). At least 17 genes were differentially expressed and able to discriminate SPH from adenoma or normal tissue. Upregulated genes were related to apoptosis inhibition, cell proliferation, transcriptional activity and cell adhesion, among other activities. Downregulated genes were mainly related to ion channel activity, lipopolysaccharides, prostaglandin-d synthase, and integral membrane proteins. CONCLUSIONS: Our data suggest that SPH and adenoma have a singular molecular signature that, theoretically, could be used for the differential diagnosis of these entities and normal parathyroid tissue.

Adenoma↗
PubMed2005

A randomized, prospective, parallel group study comparing the Harmonic Scalpel to electrocautery in thyroidectomy.

BACKGROUND: Exhaustive hemostasis is essential to successful thyroidectomy. Electrocoagulation to control bleeding has the potential risk of injuring the surrounding structures from lateral dispersion of heat. The Harmonic Scalpel (HS) cuts and coagulates simultaneously using mechanical vibration rather than high temperatures. Because its use in thyroidectomies has been limited, we sought to compare procedure parameters and complications of thyroidectomies performed using the HS with those using electrocoagulation. METHODS: Sixty patients were randomized into 2 surgical groups, HS and the standard technique using electrocautery and ligatures as the primary hemostatic method. A sample t test or Wilcoxon rank sum test was used to compare the following parameters: operative time, number of ligatures, blood loss, pain intensity, need for extra dose(s) of analgesic, incidence of recurrent laryngeal nerve palsy, and hypoparathyroidism. RESULTS: Both groups of 30 patients were comparable in age, gender, and nature of disease. In 38 patients (63%), surgery was performed for benign disease, and in 22 (37%), for differentiated carcinoma. Operative time (arithmetic mean +/- SD) was 25 minutes less in the HS group (96 +/- 23 vs 121 +/- 34, P = .005). Median number of ligatures in the HS group was 1 (range, 0-7) versus 17 (range, 6-28) ( P < .001). Mean blood loss, estimated by gauze weight, was less with HS (35 +/- 27 mL vs 54 +/- 51 mL, P = .06). Drainage during the first 24 postoperative hours and pain intensity during the first postoperative week were similar in both groups. There were no episodes of persistent nerve palsy or hypoparathyroidism in either group. CONCLUSION: The use of HS in thyroidectomies requires less operative time than does electrocoagulation.

Adult↗
PubMed2004

Correlation between radiologic and pathologic dimensions of adrenal masses.

The size of adrenal tumors has been shown to be a good predictor of malignancy. There is still some controversy about the concordance between radiologic and real pathologic measurements. The aim of this study is to determine the correlation between direct and corrected radiologic computed tomography scan dimensions and the measurements of the resected specimen. A total of 41 adrenal tumors were included. Direct and corrected measurements of the largest diameter were contrasted with the pathologic dimensions. The Linos formula was used for the corrected measurements. Proper statistics were used considering a two-tailed significance level of 0.05. The intraclass correlations using direct and corrected measurements were 0.89 [95% confidence interval (95%CI) 0.81-0.94, p = 0.00001) and 0.90 (95%CI 0.82-0.95, p = 0.00001), respectively. The bivariate analysis using Pearson's correlation between two-dimensional group variables showed r = 0.82 (p < 0.0001) when direct and pathologic measurements were compared and r = 0.83 (p < 0.0001) when the corrected values were compared with the real dimensions. In this study, we demonstrate good correlation between radiologic and pathologic measurements of adrenal tumors. The Linos formula turned out to be significantly more accurate than direct radiologic measurements when means of the groups were compared, whereas when individual correlations were determined the two were similar. The Linos formula and radiologic measurements can be used to determine the proper management of adrenal incidentalomas in individual patients.

Adolescent↗
PubMed2004

Laparoscopic Roux-en-Y gastric bypass for morbid obesity: results of our learning curve in 100 consecutive patients.

BACKGROUND: Morbid obesity requires life-long treatment, and bariatric surgery provides the best results. Among the bariatric procedures, laparoscopic Roux-en-Y gastric bypass (LRYGBP) has been considered to be superior. However, it requires advanced laparoscopic skills and a learning curve. We analyzed our results in an initial series of 100 patients. METHODS: Data of 100 consecutive patients who underwent LRYGBP for morbid obesity in a 2.5-year period were prospectively collected and analyzed with emphasis on results and complications. RESULTS: Mean age was 31+/-5 years. There were 63 woman and 37 men. Preoperative BMI was 50+/-9 kg/m(2). 33 patients were considered super-obese (BMI>50). Mean operative time was 3.8 +/- 0.7 hours. Two patients required conversion to open surgery. Mean hospital stay was 6 days. Complications occurred in 10 patients. Mortality rate was 2%. Excess body weight loss was as follows: 33 +/- 8% at 3 months (n=92), 47 +/- 2% at 6 months (n=82), 62 +/- 4% at 1 year (n= 70), 66 +/- 5% at 18 months (n= 63) and 67 +/- 8% at 2 years (n= 35). There was significant improvement in several co-morbid conditions, such as diabetes and hypertension. CONCLUSION: LRYGBP is a reproducible technique. It requires the combination of bariatric and laparoscopic expertise.

Adult↗
PubMed2004

Central pancreatectomy as an indication for various benign pancreatic tumors.

Standard pancreatic resections, either proximal or distal ones, result in a considerable loss of pancreatic parenchyma and may cause impairment of the exocrine and endocrine functions. Central pancreatectomy has been indicated for small benign lesions located in the neck or body of the pancreas. It has the potential advantage of lowering the risk of functional impairment of the pancreatic parenchyma, biliary tract, upper gastrointestinal tract, and spleen. We present three cases of patients with benign, isolated pancreatic tumors who underwent a successful central pancreatectomy. From this small series, we believe that central pancreatectomy is an excellent therapeutic option for benign, localized pancreatic tumors.

Aged↗
PubMed2004

[Laparoscopic surgery of pancreas].

UNLABELLED: In pancreatic diseases, laparoscopic surgery is used to drain fluid collections in infected pancreatic necrosis, abscesses and pseudocysts, for cancer staging, to resect both benign and malignant tumors and for palliative procedures as well. In patients with intractable pain, percutaneous or surgical celiac plexus block can be performed, celiac ganglion alcoholization and torachoscopic splacnicectomy can be done. The laparoscopic approach for staging, allows us to identify very small peritoneal or hepatic metastasis, local invasion or deep hepatic metastasis. The lack of tactile sensation is a disadvantage in the laparoscopic procedures for both staging and resection; which can be compensated utilizing laparoscopic ultrasound. The laparoscopic pancreatic approach for resection is useful to treat neuroendocrine tumors, chronic pancreatitis and cystic neoplasm allowing preservation of the splenic vessels and the spleen. The insulinoma is a treatable laparoscopic tumor given its unique characteristics. The preoperative diagnosis is made by image studies like ultrasound, CAT scans, angiography studies, MRI, endoscopic ultrasound and calcium stimulation test. There are three surgical options: enucleation, distal pancreatectomy with or without preserving the spleen. The most important complication is the pancreatic fistula. CONCLUSIONS: The laparoscopic approach in pancreatic surgery is a feasible and safe one, although, its superiority over the classic open approach has not been demonstrated yet.

Adolescent↗
PubMed2003

Telomerase activity in well-differentiated papillary thyroid carcinoma correlates with advanced clinical stage of the disease.

Clinical relevance and stage correlation of telomerase activity in well-differentiated papillary thyroid carcinoma (WD PTC) has not been well determined, as its reported activity could be due to the analysis of tumors with lymphocytic infiltrates or aggressive variants of papillary carcinomas. We conducted a prospective study of telomerase activity in WD PTC without inflammatory infiltrates and correlated it with clinical stage. Fifty WD PTCs were analyzed for telomerase activity by PCR-based TRAP (telomeric repeat amplification protocol) assay. Results were correlated with stage and other clinicopathologic variables. Twenty-one (42%) WD PTCs demonstrated telomerase activity. The enzyme was detected more frequently in stage III/IVa WD PTCs (p = 0.02) and in tumors with extra thyroidal extension (p = 0.04). The risk of presenting advanced disease (stage III/IVa) and extrathyroidal growth was significantly increased in telomerase-positive tumors (p = 0.01; odds ratio [OR] 4.4 [95%CI 1.3-14.7]) and (p = 0.04; OR 3.6 [95%CI 1.1-11.7]), respectively. Also, a correlation was found between telomerase activity and age. There was no correlation of telomerase activity with gender, histologic variant, tumor size, or cervical lymph node metastasis. Telomerase activity was observed in 42% of WD PTC and was detected more frequently in AJCC TNM stage III/IVa cases. This finding suggests that telomerase deregulation could be involved in tumor progression.

Adult↗
PubMed2003

Laparoscopic drainage of lymphocele after kidney transplant.

Lymphocele can develop after renal transplantation. Surgical internal drainage to the abdominal cavity through a standard laparotomy is indicated for symptomatic persistent lesions. Internal drainage can be performed laparoscopically. In this report, we describe our laparoscopic surgical technique for drainage and analyze our results in five patients with lymphoceles that developed after kidney transplantation. All the patients were male, with a mean age of 29 +/- 10 years. The volume of fluid in the lymphoceles ranged from 500 to 1000 mL. Percutaneous drainage was selected as the initial treatment without success. A laparoscopic peritoneal window was created in all patients under intraoperative ultrasonographic guidance. The mean operative time was 90 minutes. In all patients, the fluid collections resolved after laparoscopic internal drainage without complications. During a mean follow-up of 3 +/- 2 years, all patients remained asymptomatic, and no additional fluid collections were identified.

Adult↗
PubMed2003

Pressure-induced rhabdomyolysis after bariatric surgery.

Rhabdomyolisis most commonly occurs after muscle injury, alcohol ingestion, drug intake and exhaustive exercise. Prolonged muscle compression at the time of surgery may produce this complication. Obesity has been reported as a risk factor for pressure-induced rhabdomyolysis, but no reports associated with bariatric surgery could be found in the literature. We report 3 superobese patients who developed rhabdomyolysis after bariatric surgery. This complication was attributed to direct and prolonged pressure of the bed against the dorsal and gluteal muscles.

Acute Kidney Injury↗
PubMed2003

Surgical treatment of recurrent differentiated thyroid carcinoma.

OBJECTIVE: To describe our experience of treating recurrent thyroid carcinoma. DESIGN: Retrospective study of casenotes. SETTING: Teaching hospital, Mexico. SUBJECTS: 20 patients who developed recurrences of 273 who presented with well-differentiated thyroid carcinoma between 1991 and 1999. MAIN OUTCOME MEASURES: Presentation, management, morbidity, and mortality. RESULTS: There were 18 men and 2 women, median age 51 years (range 28-75). 13 were treated initially by total thyroidectomy and 7 with less than total resection. 16 were given ablative doses of 311I. The median time between initial resection and recurrence was 3 years (range 1-6). The sites of recurrence were cervical lymph nodes (n = 12), thyroid bed (n = 3), or both (n = 5). During a median of 3 years 10 patients were free of disease and 2 had died. CONCLUSIONS: Well-differentiated thyroid cancer usually recurs in the cervical lymph nodes. Further resection offers a high cure rate.

Adenocarcinoma, Follicular↗
PubMed2002

Videolaparoscopic resection of insulinomas: experience in two institutions.

Laparoscopic resection of islet cell tumors has been performed in some selected cases. The aim of the study was to analyze the experience of two institutions in the laparoscopic management of insulinomas. In a 4-year period, videolaparoscopic resection of sporadic insulinomas was performed in 9 patients. All patients had hypoglycemia/hyperinsulinism and a solitary tumor demonstrated by image studies. Demographics, surgical findings, results, and complications were analyzed. Mean age of the patients was 43 years. One patient was male and eight were females. One tumor was located in the head of the pancreas, 4 in the body, and 4 in the tail. Laparoscopic resection was completed in all patients. Procedures included 4 enucleations and 5 distal pancreatectomies. Pancreatic resection with splenic preservation was achieved in 4 cases. Intraoperative ultrasound was used in 7 patients. Mean size of the tumors was 1.6 cm. All patients became normoglycemic after surgery. Complications included one pancreatic fistula, one pleural effusion, and one peripancreatic fluid collection. All resolved spontaneously. In a follow-up period between 3 and 48 months no evidence of recurrence has been observed. This series supports laparoscopic resection of preoperatively localized benign solitary insulinomas. The operation provides the advantages of minimally invasive surgery and can be safely performed in most cases.

Adult↗
PubMed2002

Open versus laparoscopic vertical banded gastroplasty: a randomized controlled double blind trial.

BACKGROUND: Vertical banded gastroplasty (VBG) is a frequently used surgical procedure for the treatment of morbid obesity. It can be done open (OVBG) or laparoscopic (LVBG). The aim of this double-blind randomized clinical trial was to compare the postoperative outcome and 1-year follow-up of 2 cohorts of patients who underwent either OVBG or LVBG. PATIENTS AND METHODS: 30 patients with morbid obesity were randomized into 2 groups (14 OVBG and 16 LVBG). Pain intensity, analgesic requirements, respiratory function, and physical activity were blindly analyzed during the first 3 postoperative days. Complications, weight loss, and cosmetic results after 1 year follow-up were evaluated. RESULTS: Both groups were highly comparable before surgery. Surgical time was longer in the laparoscopic procedure. Patients in this group required less analgesics during the first postoperative day. There was an earlier recovery in the expiratory and inspiratory forces, as well as faster recovery of physical activities in patients who underwent LVBG. Postoperative complications were more frequent in the open group. Excess body weight loss after 1 year was similar in both groups. Cosmetic results were significantly better in the laparoscopic group. CONCLUSIONS: LVBG had advantages over the open procedure in terms of analgesic requirements, respiratory function, postoperative recovery, and cosmetic results.

Adult↗
PubMed2002

Quality of life in bariatric surgery.

BACKGROUND: Bariatric surgery is the treatment of choice for morbid obesity. Since bariatric operations alter gastrointestinal anatomy, they may induce symptoms that have a negative impact on quality of life (QOL). The aim of this study was to prospectively analyze QOL after bariatric surgery. METHODS: The QOL index questionnaire (GIQLI) was applied to 45 surgically treated morbidly obese patients (15 vertical banded gastroplasty, 15 Roux-en-Y gastric bypass (RYGBP), and 15 distal RYGBP) and to 15 non-operated morbidly obese controls. Follow-up was of 1-year minimum. The GIQLI evaluates physical and mental well-being, digestion and bowel habits. RESULTS: Physical and mental well-being as well as the overall QOL were significantly higher in the operated patients. There were no significant differences in digestion and bowel habits between the groups. Differences in QOL were not related to the type of surgical procedure. CONCLUSION: Overall QOL was significantly better in operated than in non-operated patients. There is no negative impact of bariatric surgery on QOL related to GI symptoms.

Adult↗
PubMedDate not supplied

Impact of surgically-induced weight loss on respiratory function: a prospective analysis.

BACKGROUND: Morbid obesity (MO) causes several degrees of respiratory impairment that may resolve after weight reduction. The aims of the present study were to investigate the frequency of respiratory impairment in a selected cohort of morbidly obese patients with BMI 40-50 kg/m(2) with no respiratory symptoms and to evaluate the impact of surgically-induced weight loss on respiratory function. METHODS: Prospective analysis of respiratory impairment was conducted before surgery and 1 year after surgery in a cohort of patients with MO who underwent vertical banded gastroplasty (VBG). 30 consecutive patients with MO who underwent VBG (14 open and 16 laparoscopic) in a 1-year period were studied. Respiratory function tests, arterial blood gases and hemoglobin were obtained in all patients before and 1 year after VBG. RESULTS: Results were analyzed using the Wilcoxon signed-rank test and Spearman for variables without normal distribution. Mean age was 35+/-8 years; there were 3 males and 27 females. BMI was 44+/-4 kg/m(2) before surgery and 32+/-4 kg/m(2) at 1-year follow-up. By respiratory function tests, the diagnosis of obstructive disease was made before surgery in 4 patients and a restrictive disorder was identified in 4 additional patients. Evidence of pulmonary disease was absent in all patients 1 year after surgery. Forced vital capacity, inspiratory and expiratory forces, tidal volume, SaO(2), and PaCO(2) significantly improved after weight reduction. CONCLUSION: Surgically-induced weight loss significantly improves pulmonary function.

Adult↗
PubMedDate not supplied

Localization of parathyroid adenomas by (99m)Tc-sestamibi scanning: upper neck versus lower neck lesions.

OBJECTIVE: To assess the diagnostic properties of (99m)Tc-sestamibi scanning (dual-phase technique) in patients with primary hyperparathyroidism and to establish the overall efficacy of this imaging technique for localization of an adenoma. METHODS: The medical records of all 131 patients who underwent parathyroid scanning in a tertiary care center between January 1997 and December 2002 were reviewed. The surgical findings were used as the "gold standard" for the diagnosis of parathyroid pathologic conditions. RESULTS: Primary hyperparathyroidism was diagnosed in 87 of the 131 patients (66.4%); of these, 76 underwent surgical treatment. In 44 patients, sestamibi scanning was also done for conditions other than primary hyperparathyroidism. (99m)Tc-sestamibi scanning had a sensitivity of 79.1%, a specificity of 86.7%, a positive predictive value of 88.3%, a false-positive rate of 11.6%, and a false-negative rate of 23.3% for the diagnosis of parathyroid adenoma. Despite the apparent high sensitivity of this scanning technique, only 58.2% of the adenomas were found intra-operatively at the location predicted by the scan. Lesions in the upper neck area were missed more frequently by sestamibi scanning than were those in the lower neck area (13 of 32 versus 1 of 35, respectively) (P<0.05). CONCLUSION: Preoperative localization of parathyroid adenomas with use of (99m)Tc-sestamibi scanning showed a limited capacity to reveal their precise location. Thus, such scans must be complemented with other studies, such as intraoperative ultrasonography and rapid parathyroid hormone assay, to ensure a successful excision if a limited surgical procedure is planned.

Adenoma↗