Performance characteristics of four immunoassays for antiepileptic drugs on the IMMULITE 2000 automated analyzer

Carbamazepine, phenobarbital, phenytoin, and valproic acid are commonly used antiepileptic drugs that show complicated pharmacokinetic behavior Nonisotopic immunoassays are used routinely to monitor these drugs, and assay specificity is important to obtain accurate results. By using samples from subjects receiving each of these antiepileptic medications, competitive immunoassays for them were evaluated on an IMMULITE 2000 automated chemiluminescent analyzer (Diagnostic Products, Los Angeles, CA). Phenytoin assays were evaluated using an additional set of samples from patients with abnormal renal function. All 4 methods were linear, had imprecision of less than 10%, and compared well with other commercial immunoassays. A positive bias was observed for phenytoin measured in samples from uremic patients compared with a high-performance liquid chromatography reference method. The molar cross-reactivity of carbamazepine-10,11-epoxide was 12% in the carbamazepine assay. Phenytoin metabolites and fosphenytoin had substantial cross-reactivity in the phenytoin assay. All antiepileptic drug assays performed well and are suitable for use in monitoring patients receiving antiepileptic drug therapy. One possible exception is the phenytoin assay with samples from patients with renal insufficiency.     

Heart tumors in children and adults: clinicopathological study of 59 patients from a surgical center.

BACKGROUND: Heart tumors are rare lesions with variegated histological types. Their clinicopathological features could be more comprehensively categorized. METHODS: This is a 19-year retrospective study of 17 infants/toddlers (<2 years of age) and 42 patients aged between 14 and 79 years (mean = 51.5) in a surgical center. RESULTS: Congenital tumors (n = 17; 29%), including rhabdomyomas (n = 9), ventricular fibromas (n = 6), and hemangiomas (n = 1), required surgery mainly because of mass effect. Familial myofibromatosis was the only embolic congenital lesion. Acquired benign tumors (n = 28; 47%) included myxomas (n = 21), fibroelastomas (n = 3), myofibroblastic inflammatory tumors (n = 2), and lipomas (n = 2). Eight (29%) were revealed by systemic embolization. These benign noncongenital tumors were all treated by complete resection, except for an incompletely resected lipoma of the mitral valve. Postoperative arrhythmia (n = 1) and pericardial effusion (n = 3) were the only complications. Primary sarcomas (n = 8; 14%) were mostly vascular tumors (five of eight), and patients with high-grade tumors had a mean survival of 15 months (n = 5). Cardiac metastases (n = 6; 10%) were from carcinomas (n = 3) or sarcomas (n = 3); apart from a necrotic metastasis, all patients died (mean survival of 6 months). CONCLUSIONS: This study shows that, regardless of patients' age, heart tumors can be classified as: (a) congenital lesions, which are spontaneously nonprogressive or regressive lesions possibly requiring surgery mainly because of mass effect; (b) acquired benign tumors, which are lesions requiring surgery often because of embolization risk; and (c) primary and secondary malignant tumors, which are lesions with globally poor prognosis but with some indications for resection.     

Fornix transection impairs conditional visuomotor learning in tasks involving nonspatially differentiated responses.

Rhesus monkeys learned a series of conditional visuomotor associations involving two-dimensional "objects" that instructed one of three responses: tapping a touch screen, steady contact with the screen for a brief period, or steady contact for a longer period. Relative to controls, fornix-transected monkeys were impaired in the acquisition of new associations and in the retention of preoperatively learned ones. These findings challenge the view that the hippocampal system participates in associative learning only when spatial information is relevant to either the stimulus or the response.     

GATA6 mutations: Characterization of two novel patients and a comprehensive overview of the GATA6 genotypic and phenotypic spectrum

The first human mutations in GATA6 were described in a cohort of patients with persistent truncus arteriosus, and the phenotypic spectrum has expanded since then. This study underscores the broad phenotypic spectrum by presenting two patients with de novo GATA6 mutations, both exhibiting complex cardiac defects, pancreatic, and other abnormalities. Furthermore, we provided a detailed overview of all published human genetic variation in/near GATA6 published to date and the associated phenotypes (n = 78). We conclude that the most common phenotypes associated with a mutation in GATA6 were structural cardiac and pancreatic abnormalities, with a penetrance of 87 and 60%, respectively. Other common malformations were gallbladder agenesis, congenital diaphragmatic hernia, and neurocognitive abnormalities, mostly developmental delay. Fifty‐eight percent of the mutations were de novo, and these patients more often had an anomaly of intracardiac connections, an anomaly of the great arteries, and hypothyroidism, compared with those with inherited mutations. Functional studies mostly support loss‐of‐function as the pathophysiological mechanism. In conclusion, GATA6 mutations give a wide range of phenotypic defects, most frequently malformations of the heart and pancreas. This highlights the importance of detailed clinical evaluation of identified carriers to evaluate their full phenotypic spectrum.     

NCAM in developing mouse gonads and ducts

Summary The expression of theNeuralCell AdhesionMolecule, NCAM, in mouse gonads and ducts was studied from fetal life to maturity. The methods used were immunocytochemical staining and Western blotting. The immunocytochemical studies showed that the only structures that remain NCAM-positive throughout life were the mesonephric-derived rete ovarii and rete testis. Also in the fetal gonads some somatic cell lining the groups of differentiating germ cells were stained. In the immature as well as in the mature ovary the granulosa cells and oocytes of growing and large follicles — but not of small follicles — were stained. A particularly strong staining of the cytoplasm of the oocyte, healthy as well as atretic, was seen. All cells of the testis remained negative except for weakly stained residual bodies and late spermatids. At all ages the male ducts showed only weak staining, whereas in the female Müllerian duct the epithelium became strongly positive at puberty. The stroma of the Müllerian duct was positive during a transitory period around day 16 of fetal life in both sexes. One-dimensional gel immunoblotting of total protein from gonads, rete and ducts from immature and mature mice showed that only the two largest isoforms of NCAM (NCAM-A and NCAM-B) were present. The gonads and the rete of both sexes and the adult uterus expressed only NCAM-B, whereas NCAM-A was also detected in the adult epididymis. The present findings suggest that NCAM may be involved in the normal development and formation of both the gonads and ducts. In particular, NCAM may play a part in sustaining the integrity of the rete testis, thus ensuring the pathway for spermatozoa from the testis to the epididymis. Furthermore this cell adhesion molecule may also be important for follicular growth and differentiation.     

Molecular determinants of human uveal melanoma invasion and metastasis

The molecular analysis of cancer has benefited tremendously from the sequencing of the human genome integrated with the science of bioinformatics. Microarray analysis technology has the potential to classify tumors based on the differential expression of genes. In the current study, a collaborative, multidisciplinary approach was utilized to study the molecular determinants of human uveal melanoma invasion and metastasis. Uveal melanoma is considered the most common primary intraocular cancer in adults, resulting in the death of approximately 50% of patients affected. Unfortunately, at the time of diagnosis, many patients already harbor microscopic metastases, thus underscoring a critical need to identify prognostic markers indicative of metastatic potential. The investigative strategy consisted of isolating highly invasive vs. poorly invasive uveal melanoma cells from a heterogeneous tumor derived from cells that had metastasized from the eye to the liver. The heterogeneous tissue explant MUM-2 led to the derivation of two clonal cell lines: MUM-2B and MUM-2C. Further morphological and functional analyses revealed that the MUM-2B cells were epithelioid, interconverted (expressing mesenchymal and epithelial phenotypes) highly invasive, and demonstrated vasculogenic mimicry. The MUM-2C cells were spindle-like, expressed only a vimentin mesenchymal phenotype, poorly invasive, and were incapable of vasculogenic mimicry. The molecular analysis of the MUM-2B vs. the MUM-2C clones resulted in the differential expression of 210 known genes. Overall, the molecular signature of the MUM-2B cells resembled that of multiple phenotypes – similar to a pluripotent, embryonic-like genotype. Validation of select genes that were upregulated and down-regulated was conducted by semiquantitative RT-PCR measurement. This study provides a molecular profile that will hopefully lead to the development of new molecular targets for therapeutic intervention and possible diagnostic markers to predict the clinical outcome of patients with uveal melanoma. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparative genomic hybridization analysis of hepatoblastoma reveals high frequency of X-chromosome gains and similarities between epithelial and stromal components

Hepatoblastoma (HB) is the most common liver tumor in childhood and differs in its environmental risk factors and genetic background from hepatocellular carcinoma. HB is associated with inherited conditions such as familial adenomatous polyposis and Beckwith-Wiedemann syndrome, suggesting the importance of genetic abnormalities in the pathogenesis and progression of this disease. It has a very polymorphous morphology. A diverse range of cytogenetic alterations has been reported to date, the most frequent being trisomy 2 and trisomy 20. Thirty-five HB specimens from 31 patients (22 purely epithelial, 4 purely mesenchymal, 9 mixed) were examined by comparative genomic hybridization (CGH), a technique that enables us to screen the entire tumor genome for genetic losses and gains. Our aims were as follows: (1) to characterize chromosome abnormalities that appear in this tumor and (2) to identify possible differences between different histologic subtypes of HB. We found significant gains of genetic material, with very little difference in the number and type of alterations between the different histologic components of HB. The most frequent alterations were gains of Xp (15 cases, 43%) and Xq (21 cases, 60%). This finding was also confirmed by fluorescent in situ hybridization performed on nuclei extracted from 6 specimens. Other common alterations were 1p-, 2q+, 2q-, 4q-, and 4q+. We found no difference between different histologic subtypes, a finding that may be in agreement with the hypothesis of a common clonal origin for the different components. An hitherto-unreported high frequency of X chromosome gains may support the assumption that X-linked genes are involved in the development of this neoplasm.