Biomedical subjects

J Palazzo

Publications and source records attributed to J Palazzo.

23 records · Page 2Linked to original sources

PubMed1989

Typical, dysplastic, congenital, and Spitz nevi: a comparative immunohistochemical study.

Nevus cell components have been observed in up to 40% of melanomas, but little is known of the pathobiology of these components in relation to their malignant potential. We studied 44 nevi of the typical, dysplastic, congenital, and Spitz types with a battery of monoclonal and polyclonal antibodies that react on formalin-fixed, paraffin-embedded tissues (HMB.45, S-100 protein, RAP-5, epithelial membrane antigen [EMA], and neuron-specific enolase [NSE]) by avidin-biotin immunohistochemical methods. EMA and RAP-5 (which detects the ras oncogene-associated P21 protein) were negative in all cases. Melanoma-specific HMB.45 was strongly reactive with the epidermal component and had a weak to negative reaction with the dermal component in the typical nevi. However, the reaction seen with HMB.45 in the junctional component of dysplastic nevi, congenital nevi, and some Spitz nevi was heterogeneous. One Spitz nevi showed HMB.45 staining in a pattern near to that of melanoma. In contrast to HMB.45, S-100 protein labeled nevomelanocytes, regardless of whether they were within the epidermis or dermis, although, in half of the dysplastic nevi, the reaction was heterogeneous, with some atypical cells failing to stain. But, with cytologically atypical junctional component (dysplastic-appearing), congenital nevi also stained heterogeneously for S-100 protein compared with the dermal component. NSE stained the central component of some Spitz nevi more intensely than the lateral component. Junctional nevomelanocytic subsets of some congenital nevi revealed HMB.45 and S-100 reactivity similar to dysplastic nevi.

Antibodies, Monoclonal↗

PubMed1988

Melanoma cell heterogeneity. A study of two monoclonal antibodies compared with S-100 protein in paraffin sections.

Fifty-six formalin, Bouin's, and Carnoy's fixed, paraffin-embedded malignant melanomas (21 primary, 35 secondary), were studied by avidin-biotin complex immunohistochemistry using monoclonal antibodies (MoAb) HMB-45 and B1.1, comparing reactivity with polyclonal anti-S-100 protein. B1.1 (anti-CEA MoAb) was expressed in a minor percentage of cells of the invasive component of some primary melanomas, and weak to moderately in scattered metastic melanoma cells. MoAb HMB-45 prepared against melanocytic tumors reacted with over 90% of all tumors studied, being weakly reactive in one, and nonreactive in four metastases. This antibody stained some primary melanomas and their dysplastic nevus components in a heterogeneous manner, but was largely nonreactive in deep dermal nevus cells that were in association with invasive melanoma, enabling recognition of the deepest penetration of melanoma cells in the dermal nevus component. MoAb HMB-45 appears specific for melanoma cells, with no cross-reactivity with nonnevomelanocytic malignant tumors (unlike polyclonal anti-S-100 protein). MoAb HMB-45 is more sensitive in detecting malignant melanoma cell heterogeneity than anti-S-100 protein.

Antibodies, Monoclonal↗

PubMedDate not supplied

Cirrhosis: multiobserver analysis of hepatic MR imaging findings in a heterogeneous population.

To investigate the magnetic resonance (MR) imaging findings of hepatic cirrhosis and the potential of MR imaging in differentiating cirrhosis from other hepatic abnormalities, three observers with different levels of expertise in MR imaging (specialist, experienced radiologist, and novice with special training) reviewed hepatic MR imaging examinations of 52 patients with biopsy-proved presence (n = 29) or absence (n = 23) of cirrhosis. All examinations included motion-compensated T1-weighted, T2-weighted, and flow-sensitive gradient-echo images. For all three observers, linear signal irregularity was more accurate than other findings. For the final diagnosis of cirrhosis, the specialist was most sensitive (76% at high threshold, 97% at low threshold), followed by the novice with special training (31% and 79%, respectively). Specificity was 100% for all observers at high threshold and 78%, 96%, and 87% for expert, experienced, and trained novice observers, respectively, at low threshold. Sensitivity did not vary regardless of severity of fibrosis, as determined independently by a hepatopathologist. MR imaging has the potential of offering a comprehensive noninvasive evaluation of patients with suspected cirrhosis, but considerable expertise is required at present.

False Positive Reactions↗

PubMedDate not supplied

Hepatocellular tumors with high signal on T1-weighted MR images: chemical shift MR imaging and histologic correlation.

We reviewed conventional and chemical shift MR images and histologic findings of seven proven primary hepatic masses that had higher signal than liver on T1-weighted images to determine if this necessarily indicates fat and if the presence of fat indicates malignancy. These seven masses included five hepatocellular carcinomas (HCCs), one focal nodular hyperplasia (FNH), and one fatty dysplastic nodule. An eighth solitary high signal mass without histologic proof had evidence of abundant fat on each of two chemical shift MR images 25 months apart. Only one of the five HCCs had chemical shift or histologic evidence of fat, while the FNH and dysplastic nodule each had both chemical shift and histologic confirmation of fat. The dysplastic nodule became more dysplastic and grew significantly within 14 months, but remained benign. The unproven fatty lesion decreased in size over 25 months and is therefore presumably benign. Although no statistical inferences can be drawn from this small correlative study, we have shown that HCC may have higher signal intensity than liver on T1-weighted images, whether or not it contains fat. Chemical shift techniques can confirm the presence of intratumoral fat and thus indicate a mass of hepatocellular origin, but the mass may be benign or malignant.

Biopsy↗

PubMedDate not supplied

Stimulating conversations in needle EMG.

Needle electromyography (EMG) is a widely used modality that has been available for decades. Yet never has this invasive mode of EMG been enveloped in greater controversy than it is today. To explain the status--and future--of needle EMG while casting light upon the controversies surrounding it, Rehab Management spoke with three noted specialists in the field.

Certification↗