PBAT biodegradable mulch films: Study of ecotoxicological impacts using Allium cepa, Lactuca sativa and HepG2/C3A cell culture

Biodegradable mulch films are an alternative to polyethylene films used in agriculture for weed control, improving crop productivity. This change could minimize the residue production and costs related to the final disposal. Nevertheless, the environmental safety of these biodegradable products is scarcely investigated. In this work, samples of poly(butylene adipate-co-terephthalate)-PBAT mulch films, with and without UV stabilizer additives, were prepared. Aqueous extracts of soil samples, where mulch films were disposed, were investigated using bioassays with Lactuca sativa, Allium cepa, and cell culture HepG2/C3A. As PBAT is expected to suffer photodegradation and biodegradation, soil samples mixed with films before and after these processes were evaluated. Soil aqueous extracts promoted root grown (mainly hypocotyl) of L. sativa, probably due to presence of nutrients. So, to evaluate toxicity potential, in this case it was necessary to use aqueous extract prepared with soil instead of ultrapure water as the control. After doing this analysis it was observed that no adverse impacts due to PBAT films occurred. No chromosomal abnormalities were observed in A. cepa bioassay for any of tested samples. The absence of genotoxic potential was confirmed by comet assay and micronucleus test using human hepatocarcinoma cell line HepG2/C3A. These results showed that the soil did not induce damage to the tested organisms, before and after degradation of PBAT films.

Modelos de percolação elétrica aplicados para compósitos poliméricos condutores

Resumo O presente artigo apresenta a aplicação e adequação dos modelos de percolação elétrica em trabalhos experimentais e teóricos da literatura para compósitos poliméricos condutores. Foi realizado um levantamento das publicações referentes aos modelos estudados para os diferentes tipos de cargas condutoras mais aplicadas na preparação destes compósitos, tais como pós metálicos, grafite, negro de fumo, nanofibras e nanotubos de carbono. A discussão está apresentada quanto à adequação dos modelos ao comportamento dos compósitos na influência das cargas nas propriedades elétricas de matrizes poliméricas.

Influência das condições de mistura e dos teores de Acetato de Vinila e de argila nas propriedades de nanocompósitos de EVA/montmorilonita organofílica

O copolímero Etileno Acetato de Vinila (EVA) é uma poliolefina utilizada principalmente em filmes para embalagens, onde a sua flexibilidade, tenacidade, elasticidade e transparência são atributos desejáveis. As propriedades mecânicas, térmicas e de barreira do EVA podem ser melhoradas pela incorporação de cargas inorgânicas. O EVA apresenta polaridade variável de acordo com o teor de Acetato de Vinila, o que promove a viabilidade para obtenção de nanocompósitos com argilas organicamente modificadas, tornando desnecessária a adição de agentes compatibilizantes. Neste trabalho foram preparados nanocompósitos de EVA e montmorilonita organofílica comercial pelo método de intercalação do fundido em um reômetro de torque, com rotores tipo roller, a 150°C durante 10minutos, com monitoramento do torque em função do tempo. A fim de investigar a influência da polaridade do EVA, da concentração da argila e das condições de processamento nas características dos nanocompósitos, variou-se a concentração de Acetato de Vinila (19% e 28%), o teor de argila (2% e 5%) e a velocidade de rotores (60 rpm e 100 rpm). Foram avaliadas a estrutura da argila, a estabilidade térmica e as propriedades mecânicas e de barreira dos nanocompósitos, mediante as técnicas de difração de raios X, análise termogravimétrica, ensaio de tração e análises de taxa de permeabilidade ao oxigênio e ao vapor d’água. A partir dos dados de permeabilidade foi aplicado o modelo de Nielsen para avaliar o grau de esfoliação da argila. Dentre os principais resultados com o planejamento fatorial destacam-se: (a) o aumento da polaridade do EVA aumentou a permeabilidade ao oxigênio e ao vapor d’água dos materiais; (b) o teor de argila não modificou a estabilidade térmica dos nanocompósitos e a estrutura da argila; (c) o aumento da concentração da argila aumentou o módulo elástico, reduziu a deformação de ruptura e reduziu significativamente o coeficiente de permeabilidade ao oxigênio e ao vapor d’água; (d) o fator rotação não implicou em alterações significativas em nenhuma das respostas avaliadas.

Immunohistochemistry of Tissue Prepared by a Molecular-Friendly Fixation and Processing System

A recently introduced histologic fixative (Universal Molecular Fixative [UMFIX]) has been shown to preserve macromolecules in tissue at ambient temperature. When UMFIX-exposed tissues are processed by a formalin-free, microwave-assisted rapid processing system, the resulting paraffin blocks retain good histomorphology and intact nucleic acids suitable for expression microarray analysis. Because UMFIX may be used as an alternative to formalin, the authors set out to study the effect of this new fixation and processing system on immunohistochemistry (IHC) by analyzing a range of human neoplastic and non-neoplastic specimens. Parallel slices from surgically removed specimens were fixed in formalin and UMFIX and processed in a rapid microwave-assisted tissue processor. IHC was performed following routine procedures. The staining for those antibodies that normally required antigen retrieval was carried out with and without that step. The intensity and pattern of reactions were compared in 144 tissue samples fixed by the two methods using 70 monoclonal and polyclonal antibodies. The intensity of IHC reactions for most cytoplasmic antigens was generally equal or stronger in UMFIX tissues. This was particularly true with intermediate filaments and HercepTest, where the antigen retrieval step became unnecessary. Conversely, there was a decrease in the intensity of reactions for HepPar1, bcl-2, and three nuclear antigens (Ki-67, TTF-1, and estrogen receptor). Increasing their exposure times optimized the sensitivity of the latter four antibodies. The study shows that IHC staining results of tissues fixed in UMFIX and processed by the microwave-assisted system are comparable to those obtained on formalin-fixed, similarly processed specimens. There is an enhancement of the sensitivity of few antibodies in UMFIX-exposed tissue, rendering antigen retrieval unnecessary. This increased sensitivity may be due to the effect of eliminating formalin from fixation and processing or the microwave energy.

One- and two-photon fluorescence anisotropy of selected fluorene derivatives

The steady-state excitation anisotropy spectra of fluorene derivatives were measured in viscous solvents, under the one- and two-photon excitation, over a broad spectral range (UV-Visible). The orientation of their absorption transition moments for the first, S0 --> S1, and second, S0 --> S2, excited states were determined. It was shown experimentally that a decrease in the angle between S0 --> S1 and S0 --> S2 transitions corresponded to an increased value of two-photon absorption (2PA) cross section for these molecules. Two-photon excitation anisotropy was nearly constant over the spectral region investigated (in contrast to one-photon excitation anisotropy spectra) and can be roughly explained by a simple model of 2PA based on the single intermediate state approximation. For comparison, the same trend in two-photon excitation anisotropy was observed for Rhodamine B in glycerol.

Antimicrobial activity of UMFix tissue fixative

AIMS

The aim of this study was to determine the antimicrobial effects of UMFix, an alcohol based tissue fixative, on various microorganisms. The UMFix solution was compared with 10% neutral buffered formalin.

METHODS

Standard methods to determine microorganism colony counts were performed after exposure of the microorganisms to UMFix and 10% neutral buffered formalin.

RESULTS

After a short exposure, UMFix rapidly killed vegetative bacteria, yeasts, moulds, and viruses. Bacterial spores were resistant to killing by UMFix. All organisms were killed by the 10% neutral buffered formalin preparation.

CONCLUSIONS

UMFix was microbicidal for vegetative bacteria, yeasts, and aspergillus species after a short exposure, although it was not active against spore forming bacillus species. The methanol content of the fixative was responsible for the killing effect of this fixative. No killing was seen when polyethylene glycol was used alone.

Resonant enhancement of two-photon absorption in substituted fluorene molecules

The degenerate and nondegenerate two-photon absorption (2PA) spectra for a symmetric and an asymmetric fluorene derivative were experimentally measured in order to determine the effect of intermediate state resonance enhancement (ISRE) on the 2PA cross section delta. The ability to tune the individual photon energies in the nondegenerate 2PA (ND-2PA) process afforded a quantitative study of the ISRE without modifying the chemical structure of the investigated chromophores. Both molecules exhibited resonant enhancement of the nonlinearity with the asymmetric compound showing as much as a twentyfold increase in delta. Furthermore, the possibility of achieving over a one order of magnitude enhancement of the nonlinearity reveals the potential benefits of utilizing ND-2PA for certain applications. To model ISRE, we have used correlated quantum-chemical methods together with the perturbative sum-over-states (SOS) expression. We find strong qualitative and quantitative correlation between the experimental and theoretical results. Finally, using a simplified three-level model for the SOS expression, we provide intuitive insight into the process of ISRE for ND-2PA.

Multiple mutations of the p53 gene in human mammary carcinoma

Alteration of the p53 tumor suppressor gene is the most common genetic abnormality in human cancer. In breast cancer, depending on the stage of disease and method of detection, mutation rates of 25-60% have been observed. Multiple mutations of p53 gene in the same tumor however, are rarely reported. In this study we explored the frequency of multiple mutations of p53 gene in mammary carcinoma in a cohort of south Florida patients. Three hundred eighty-four cases of primary breast cancer diagnosed between 1984 and 1986 at the University of Miami, Jackson Medical Center were subjects of this study. Sequence analysis of exons 5 through 8 of p53 was performed on cloned PCR-amplified DNA of formalin-fixed, paraffin-embedded tumors. Two hundred thirty-four of 384 breast cancers (61%) had p53 mutation. Of those, 36 tumors showed more than one mutation; 31 tumors had two mutations, three showed three, one tumor had five mutations, and one case carried six mutations. The majority of mutations were missense (43) followed by silent (35); and most occurred within a single exon. Our study suggests that multiple mutations of p53 suppressor gene in breast cancer are more common than currently believed.

Frequency and pattern of p53 gene mutation in a cohort of Spanish women with node-negative breast cancer

Ethnic, racial and regional differences in the frequency and pattern of p53 gene mutations have been well documented. Some of these differences have been shown to have an impact on the survival of patients with breast cancer. In this study we explored the frequency and pattern of p53 abnormality in a cohort of Spanish women with node-negative breast cancer using PCR, subcloning and DNA sequencing of archival tumors. One hundred and seventy-eight cases of breast cancer diagnosed between 1981 and 1986 at the University of Oviedo Hospital in Oviedo, Spain were subjects of this study. Sequence analysis of exons 5 through 8 of p53 was performed on subcloned PCR-amplified DNA, extracted from formalin-fixed, paraffin-embedded tumors. Appropriate positive, negative, PCR, and polymerase controls were utilized and evaluated. Duplicate samples of the genomic DNA were re-evaluated on all cases showing more than one mutation. One hundred and five out of 178 breast cases (59%) carried one or more p53 gene mutations. Mutations were distributed randomly from codon 128 to 305. There were 123 (88%) transition, 10 (7%) transversion, 5 (3.5%) splice junction mutations, and 2 (1.5%) deletions. Eighty-three cases (61.5%) had missense mutation, 45 (33.5%) silent, 5 (3.5%) nonsense and 2 (1.5%) frameshifts. Eighty (75%) of 120 transitions were G:C to A:T, 11 (25%) of which occurred at CpG sites. Sixteen mutations were in novel codons not reported in breast cancers previously. Codons with the highest frequency of mutations in this group were 278, 273, 213 and 227. We also detected 27 tumors with more than one mutation within a single exon or in different exons in the same patient. These findings suggest that the frequency and pattern of p53 mutations in this group of Spanish women with breast cancer is different than those reported in the United States and Northern Europe.

Laminin receptor in lymph node negative breast carcinoma

BACKGROUND

Expression of 67 kD laminin binding protein, 67LR, is reported to be associated with invasive and metastatic phenotypes in several types of human malignancies. In mammary carcinomas, however, the biologic role of 67LR has been less clear. The authors explored the potential biologic significance of expression of 67LR in 148 patients with axillary lymph node negative breast carcinoma.

METHODS

Formalin fixed, paraffin embedded histologic sections were immunohistochemically evaluated for 67LR using monoclonal antibody MLuC5. The staining results were correlated with morphologic data as well as with estrogen receptor content and p53 product accumulation.

RESULTS

There were statistically significant correlations between positivity for 67LR and lower histologic grade (P = 0.003), lower nuclear grade (P = 0.002), positivity for estrogen receptor (P = 0.003), and lack of p53 abnormality (P < 0.001). Expression of 67LR had no independent effect on the disease free or overall survival of lymph node negative patients with breast carcinoma. Nevertheless, in the subgroup of 67LR positive patients, positivity for estrogen receptor was associated with significantly longer overall survival (P = 0.008).

CONCLUSIONS

The data from this study suggest that tissue expression of 67LR, as detected by antibody MLuC5, is associated with better differentiated, less aggressive forms of axillary lymph node negative breast carcinoma.

Detection of p53 gene abnormality by sequence analysis of archival paraffin tissue. A comparison with fresh-frozen specimens

This parallel study was designed to compare the sensitivity and specificity of detection of point mutations in fresh-frozen and formalin-fixed, paraffin-embedded breast cancer tissue. Sequence analysis of exon 5 of p53 gene was performed on polymerase chain reaction-amplified DNA from 25 infiltrating ductal carcinomas of the breast. Four tumor showed mutations with identical base substitutions in their respective codons of both frozen and paraffin-embedded specimens. We conclude that subtle genetic alterations can be detected in archival paraffin tissue with an accuracy comparable to that of fresh-frozen histologic samples.

Cathepsin D in host stromal cells, but not in tumor cells, is associated with aggressive behavior in node-negative breast cancer

One hundred fifty-four axillary lymph node-negative invasive ductal carcinomas of the breast were immunohistochemically evaluated for the expression of cathepsin D. Formalin-fixed paraffin sections of each tumor were stained using a polyclonal antibody raised against recombinant procathepsin D. Cathepsin D content of tumor cells and host histiocytes and fibroblasts within or immediately at the invasive border of tumors were assessed separately and correlated with histomorphology, estrogen-receptor content, and patients' survival data. Positive cathepsin D staining of tumor cells was associated with a lower nuclear grade and well-differentiated histology, whereas moderate to strong staining of host cells correlated with larger tumor size, higher nuclear grade, poorly differentiated histomorphology, and lack of estrogen-receptor (ER) protein. No statistically significant correlation was found between cathepsin D in tumor cells and survival. There was, however, a statistically significant correlation between moderate to strong cathepsin D staining of host cells and shorter disease-free and overall survivals. Expression of cathepsin D by host cells, however, did not have an independent influence on survival. The authors conclude that cathepsin D in stromal cells, but not in tumor cells, is associated with aggressive behavior in node-negative invasive ductal carcinomas of breast. Furthermore, determination of cathepsin D in cytosolic extracts of tumors is of no practical value because it may represent cathepsin D content of tumor cells, intratumoral host cells, or both.

Remodeling of human myocardial collagen in idiopathic dilated cardiomyopathy. Role of metalloproteinases and pyridinoline cross-links

A major contribution to the mechanical strength of the heart is provided by a continuous fibrillar collagen network embracing individual myocytes and forming an interstitial and perivascular framework. This study explores the possibility that idiopathic dilated cardiomyopathy may involve extensive changes in this collagenous framework. Idiopathic dilated cardiomyopathy hearts were obtained at transplant and compared with control hearts from autopsy. Idiopathic dilated cardiomyopathy showed a doubling of collagen concentration and a quadrupling of the total collagen per heart, whereas the stable mature cross-link, pyridinoline, diminished from 2.07 mol/mol of collagen to 1.0. Neutrophil-type collagenase activity is elevated approximately 30-fold as is the activity of gelatinase. Tissue inhibitor of metalloproteinase activity falls to negligible levels in idiopathic dilated cardiomyopathy, whereas alpha 2-macroglobulin is high. It is postulated that collagen critical to mechanical stability of the heart is degraded by metalloproteinase activity and is replaced by fibrous intercellular deposits of poorly cross-linked collagen. These changes contribute to weakening and dilatation of the ventricular wall.

Intramural left anterior descending coronary artery: significance of the depth of the muscular tunnel

To establish whether an intramural left anterior descending coronary artery (LADA) is a simple anatomic or a singularly pathologic variant we studied 39 hearts, each with an intramural course of the LADA and no coronary artery disease, valvular derangement, cardiomyopathy, or congenital anomaly. Seventeen of the 39 hearts had no myocardial lesions, while 22 had gross and/or microscopic alterations in the myocardial territory supplied by the intramural LADA. The myocardial lesions consisted of one or more of the following: interstitial fibrosis, replacement fibrosis, contraction band necrosis, and/or increased vascular density in areas of focal fibrosis. The coronary anatomy of the 22 hearts with myocardial lesions (group 1) was compared with that of the 17 hearts without myocardial changes (group 2). Each of the group 1 hearts had an intramural LADA deeply placed within the ventricular wall and attenuation of potential collateral blood flow because of a co-existing intramural course of the posterior descending artery, other epicardial coronary arteries, and/or a diminutive right coronary artery. The myocardial changes in group 1 hearts and their absence in group 2 hearts suggest that the deep, intramural LADA of the group 1 hearts is abnormal rather than a simple anatomic variant of normal. Furthermore, the deep intramural LADA may be associated with sudden death since 13 of the 22 group 1 hearts were from sudden death victims. Six of these 13 persons died suddenly during vigorous exercise.

Myxoid heart disease: an assessment of extravalvular cardiac pathology in severe mitral valve prolapse

Because of the microscopic features of the affected leaflets in mitral valve prolapse (MVP), myxoid degeneration of the valve is a common pathologic designation applied to this condition. We undertook this study as a means of gaining an insight into the occurrence and prevalence of extravalvular cardiac alterations in hearts with severe MVP. Tissues of 24 hearts with severe myxomatous transformation of the mitral valve as the sole cardiac abnormality were examined. Eighteen of the 24 subjects with severe MVP died suddenly. Only two of these had pathologic evidence of severe mitral insufficiency. Twenty-four normal hearts served as controls. The two groups of hearts came from victims of homicide, suicide, accident, or natural death. Sections of the mitral valve, working myocardium, conduction system, and cardiac nerves and ganglia were studied by routine and special connective tissue and proteoglycan stains. Similar to the findings in severely affected mitral valves, prominent deposits of proteoglycans in neural and conduction tissue readily distinguished hearts with myxomatous valve changes from the control hearts. We conclude that the commonly recognized local derangement of valvular tissue in MVP is but one specific reflection of a more general myxomatous alteration in cardiac connective tissue.

Myocarditis simulating acute transmural myocardial infarction

A patient with cardiogenic shock had typical electrocardiographic findings of acute anterior transmural myocardial infarction. Cardiac catheterization revealed normal coronary arteries and severe biventricular failure. Postmortem examination confirmed normal coronary arteries; acute myocarditis, but no evidence for infarction, was found. Electrocardiographic changes of myocarditis may be indistinguishable from acute transmural infarction. In suspected cases, cardiac catheterization should be considered prior to thrombolytic therapy.

Histologic markers in primary and metastatic tumors of the liver

To investigate the value of different tissue markers in the histologic diagnosis of hepatic tumors, we performed immunoperoxidase stains for alpha-fetoprotein (AFP), alpha-1-antitrypsin (AAT), carcinoembryonic antigen (CEA), and an erythropoiesis-associated antigen (ERY-1) on formalin-fixed, paraffin-embedded samples from 107 primary and metastatic tumors of the liver. AFP was present in 17% of the hepatocellular carcinomas, in 7% of the metastatic carcinomas, and in none of the cholangiocarcinomas. AAT was present in 41% of the hepatocellular carcinomas, in 37% of the cholangiocarcinomas, and in 50% to 70% of the metastatic carcinomas of the liver. Intracytoplasmic CEA was found in 75% of the cholangiocarcinomas, in 92% to 100% of the metastatic carcinomas, and in only one of the mixed hepatocellular-cholangiocarcinomas. ERY-1 was present in 89% of the hepatocellular carcinomas, whereas none of the cholangiocarcinomas or metastatic carcinomas stained for this marker. We conclude that immunohistochemical assays for AFP and AAT are of limited value in the differential diagnosis of hepatic tumors. However, immunohistochemical stains for ERY-1 and CEA can be valuable in differentiating hepatocellular carcinomas from metastatic tumors.

C-cell hyperplasia in thyroid tissue adjacent to follicular cell tumors

An immunohistochemical study was conducted on the number and distribution of C-cells in the nonneoplastic thyroid tissue adjacent to tumors of follicular cell origin. It consisted of 49 cases, of which 25 were papillary carcinomas, 22 were follicular adenomas, and 2 were follicular carcinomas. Twenty normal adult thyroids from the Broward's Medical Examiner's morgue served as controls. In 17 of the 49 cases (34.6%), there was a statistically significant increase in the number of C-cells in the normal-appearing thyroid tissue adjacent to follicular cell tumors, with at least 50 C-cells in one low power field, while only one of 20 normal thyroids had a similar number of cells. (P = .02; chi 2 = 5.05). In two tumor cases there were more than 100 C-cells in several low power fields with formation of small C-cell nodules similar to those described in the type II Multiple Endocrine Neoplasia Syndrome (MEN). It was concluded that the nonneoplastic thyroid tissue adjacent to 34.6% of tumors with follicular cell phenotypes contains significantly more C-cells than those present in normal adult thyroids. The possible pathogenesis and clinical significance of these findings are discussed.

Nocardia asteroides aortitis with perforation of the aorta

A 53-year-old man died of nocardial aortitis eight months after undergoing aortic valve replacement. Autopsy revealed vegetation in the area of a previous aortotomy incision and a small perforation of the aorta enclosed by pericardium immediately above the prosthetic valve ring. Prosthetic valve endocarditis was not present. Multiple splenic infarcts, microabscesses of both kidneys, and myocarditis were identified. Antemortem blood cultures and postmortem cultures of the aortic vegetation grew Nocardia asteroides.

Prekeratin immunohistochemistry in the diagnosis of undifferentiated carcinoma of the nasopharyngeal type

We investigated the value of prekeratin immunostaining in establishing the diagnosis of undifferentiated carcinoma of the nasopharyngeal type (lymphoepithelioma). As in squamous cell carcinoma of the nasopharynx, all seven lymphoepithelial carcinomas stained for prekeratin whereas other look-alike but histogenetically different neoplasms (malignant lymphoma, esthesioneuroblastoma, and small round cell sarcomas) did not stain. In addition to confirming the squamous epithelial nature of lymphoepithelioma, our findings indicated that immunoperoxidase staining for prekeratin is a useful diagnostic tool in the differential diagnosis of nasopharyngeal carcinomas in general and lymphoepithelioma in particular.

Maximizing the effectiveness of the autopsy in cases of sudden death

Autopsies are essential in the investigation of sudden unexpected deaths. To maximize the effectiveness of the autopsy in these cases, the pathologist must assess the circumstances leading to the person's death, should be knowledgeable of the diseases most often responsible for sudden death, and should use dissection techniques most appropriate for their disclosure. In adults, the great majority of sudden deaths are cardiogenic and related to diseases of the coronary arteries, cardiac valves, or myocardium. In infants and young children, however, extracardiac diseases are prevalent in the causation of sudden deaths. Approximately one third of these are inexplicable (sudden infant death syndrome).

Clear cell variant of thyroid carcinoma

Three carcinomas composed of a variable proportion of clear cells, oxyphil cells, and cells with combined oxyphil and clear cell features are reported. Cytologically, these tumors were included in the category of oxyphil cell variant of follicular carcinoma. In regard to pattern, two were entirely follicular, and one had follicular and papillary areas. The biologic behavior of these tumors, however, was consistent with that of follicular carcinomas. The clear cell change could be the result of chronic TSH overstimulation. This may explain the variable histological patterns, nuclear features, and biologic behavior associated with these tumors. These tumors bear a striking histologic resemblance to metastatic renal cell carcinoma and clear cell neoplasms from other sites. Immunocytochemical stain for thyroglobulin proved to be a specific and sensitive method for identification of these tumors.

Immunohistochemical markers for prostatic cancer

In a patient with an unclassifiable primary or metastatic neoplasm, with or without a history of prostatic cancer, immunostaining for PA or PSAP may prove invaluable. The procedure is simple, rapid, inexpensive, and extremely accurate in demonstrating the prostatic origin of tumors. It should be noted however, that the specificity of results is entirely dependent upon the specificity of the primary antibody, which should be meticulously defined before the procedure is used for diagnostic purposes.

Carcinoembryonic antigen in normal, preneoplastic and neoplastic gallbladder epithelium

Carcinoembryonic antigen (CEA) was found in normal epithelium, premalignant lesions, and all histologic types of carcinomas of the gallbladder. Immunocytochemical staining for CEA was limited to the apical surface of normal epithelium. In premalignant lesions and in carcinomas, the staining was more extensive, occurring within the cytoplasm and gland secretions. These findings show that the presence and the pattern of distribution of CEA in normal and neoplastic gallbladder epithelium closely resemble that in other gastrointestinal epithelia.

Prekeratin in spindle cell tumors of the skin

A variety of benign and malignant skin lesions was stained for the presence of prekeratin using an unlabeled antibody peroxidase-antiperoxidase method and an antibody raised against human prekeratin protein. No prekeratin could be detected in benign or malignant lesions derived from melanocytes, and prekeratin could not be found in atypical fibroxanthoma, Kaposi's sarcoma, angiosarcoma, dermatofibrosarcoma protruberans, and leiomyosarcoma. Paget's cells did not contain prekeratin. Varying staining intensities were observed in keratinocytic atypical hyperplasias. Of particular interest is the observation that many spindle cell lesions that were difficult to identify with 100% assurance from routine stains could be positively identified as squamous cell carcinoma after prekeratin was found in the atypical cells.

Immunoreactive prekeratin in Brenner tumors of the ovary

In an attempt to further characterize benign, proliferating, and malignant Brenner tumors, immunoperoxidase staining for prekeratin was undertaken in a group of these neoplasms as well as in a variety of histologically different tumors of the ovary. All Brenner tumors reacted positively for prekeratin, whereas none of the other epithelial or sex cord-stromal tumors of the ovary stained. On the basis of these findings, we conclude that prekeratin might be a useful marker for differentiating malignant Brenner tumors from histologically similar, poorly differentiated ovarian neoplasms.

Thyroglobulin in carcinoma of the thyroid: an immunohistochemical study

To determine the value of thyroglobulin as an immunohistochemical marker for thyroid neoplasms, we studied 42 primary thyroid carcinomas, 38 metastatic carcinomas, and four sarcomas involving the thyroid gland. All follicular and papillary carcinomas, regardless of their morphologic variation, stained positively for thyroglobulin, whereas the medullary carcinomas, metastatic tumors, and sarcomas showed negative staining reactions. The only small-cell variant of follicular carcinoma and ten of 14 spindle and giant cell carcinomas showed the lowest thyroglobulin reactivity. It is concluded that immunohistochemical demonstration of thyroglobulin is a sensitive and specific method of identifying thyroid carcinomas of follicular cell origin.

Paget's disease of the skin. A unifying concept of histogenesis

Utilizing the peroxidase antiperoxidase technique we explored the presence and the distribution of carcinoembryonic antigen (CEA) in seven cases of mammary and sixteen of extramammary Paget's disease of skin. In every case positive immunostaining was observed in all the Paget's cells and the underlying tumor (where one was present), whereas intervening keratinocytes and melanocytes did not stain. CEA was also present in the cells and secretions of normal eccrine and apocrine glands. Our observations confirm that Paget's cells are of glandular origin.

Carcinoembryonic antigen in sweat-gland carcinomas

Using standard immunoperoxidase techniques, four cases of malignant sweat-gland carcinoma were examined for the presence of carcinoembryonic antigen (CEA). This substance was universally present in these lesions in spite of their wide spectrum of histologic features. CEA was mainly localized within the cytoplasm of tumor cells and in the lumina of neoplastic glands. The findings indicate that the presence of CEA in malignant skin adnexal tumors could help to identify and categorize these lesions as derived from eccrine or apocrine adnexal epithelium.

Polyacrylamide-bismuth for postmortem coronary arteriography

High quality postmortem human coronary arteriograms are obtained by injecting an acrylamide-bismuth mixture into the isolated aortic root under physiologic pressure. The acrylamide advances to the terminal size (20 micrometer.) arterioles, polymerizes, and remains within the vessels during the processing of tissue for histologic studies. Because the polyacrylamide does not affect the arterial wall morphology or the surrounding myocardium, the acrylamide-bismuth injection technique offers the clarity of the cast-corrosion procedure for postmortem radiograms fo the epicardial and intramural coronary arteries and adds the capability for histologic studies of arterial and myocardial tissues.

Hemangioblastomas: histogenesis of the stromal cell studied by immunocytochemistry

Twenty-one cases of hemangioblastoma from the cerebellum, spinal cord and retina were studied using the unlabeled antibody peroxidase-antiperoxidase technique with antibodies directed against glial fibrillary acidic protein (GFAP) and factor VIII related antigen (VIIIR:Ag). In 19 of 21 cases studied with anti-GFAP, astrocytes were identified peripherally, and in 13 cases they were found centrally within the tumor. In no instance did stromal cells react positively for GFAP. Sixteen cases with anti-VIIIR:Ag antibody were examined, and in all cases many stromal cells showed positive staining. It is concluded that the stromal cells were of endothelial origin. The occasional stromal cells that other investigators have identified as reacting positively for GFAP may represent stromal cells capable of ingesting extracellular GFAP derived from reactive astrocytes within the tumor, or they may be lipidized astrocytes.

Early electrophysiologic and anatomic alterations in cat ventricular muscle after coronary artery ligation

The effect of coronary artery ligation on electrophysiologic properties of cat ventricular muscle cells was studied. Depression of resting potential, action potential rate of rise and amplitude was observed in infarcted cells, 30 min to 5 days after ligation. Action potential duration was markedly shortened in acute stages (30-120 min) but gradually lengthened to above control by 48 h. Anatomic sequelae included oedema, loss of fibre striation and cellular necrosis.

Prostatic-specific antigen: an immunohistologic marker for prostatic neoplasms

Antiserum to a human prostate-specific antigen was raised in a rabbit and utilized by immunoperoxidase staining to evaluate its potential value as a diagnostic histologic marker for tumors of prostatic origin. All primary and metastatic prostatic malignancies reacted positively, whereas nonprostatic neoplasms did not stain with this procedure. This is the first immunohistochemical marker for prostate gland epithelium which does not represent prostatic acid phosphatase.