Biomedical subjects

Juan Pablo Pantoja

Publications and source records attributed to Juan Pablo Pantoja.

3 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↗

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↗

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↗