Unusual variants of adrenal pseudocysts with intracystic fat, myelolipomatous metaplasia, and metastatic carcinoma

Five previously unreported cases of adrenal pseudocysts are described that demonstrate a wider range of histologic appearances than has been previously recognized in these lesions. One pseudocyst removed from an asymptomatic 59-year-old female contained intracystic nests of cytologically malignant cells of unknown origin. Workup revealed a left breast mass, which on biopsy showed an infiltrating ductal carcinoma with neoplastic cells that were cytologically similar to those found within the cyst contents. Four other pseudocysts are described with variable numbers of intracystic vascular structures and benign adrenal cortical cells. In addition, intracystic mature adipose tissue was observed in all four cases, with myelolipomatous metaplasia found in one. Awareness of the wide histologic variability of these lesions should improve diagnostic accuracy and allow distinction from adrenocortical neoplasia and myelolipoma.

Thymomas and thymic carcinomas

This review discusses epithelial proliferations of the thymus, excluding carcinoid tumor and small cell carcinoma. The clinical features of thymoma, possible etiologic mechanisms, and associated autoimmune and paraneoplastic conditions are summarized briefly. Histologic subtypes of thymoma, including lymphocyte predominant, mixed, and spindle cell tumors are described and illustrated. The concept of "medullary" and "cortical" differentiation in thymoma is reviewed. Immunohistochemical and electron microscopic features of this neoplasm are presented. Flow cytometric studies relating to its prognosis also are summarized. Distinctions between encapsulated thymoma, invasive thymoma, and metastatic or "malignant" thymoma are described in detail. Thymic carcinomas are reviewed, as distinguished from cytologically bland thymomas. Variants of thymic carcinoma include squamous cell, spindle cell, lymphoepithelioma-like, mucoepidermoid, adenosquamous, clear cell, basaloid, and adenoid cystic neoplasms.

Olfactory neuroblastoma. Additional immunohistochemical characterization

A panel of 12 antibodies was used to further characterize the immunohistochemical staining profile of olfactory neuroblastoma. The following results were obtained for the 11 neoplasms that were immunostained: neuron-specific enolase 11/11(+), S-100 protein 8/11(+), microtubule-associated protein-2 8/11(+), class III beta-tubulin isotype 9/11(+), neurofilament 200 kD 8/11(+), synaptophysin 7/11(+), glial fibrillary acidic protein 1/11(+), chromogranin A 1/11(+), vimentin 1/11(+), keratin (CAM 5.2) 4/11(+), keratin (AEI/AE3) 0/11(+), and epithelial membrane antigen 0/11(+). Expression of two intermediate filaments was found in 4 of the 11 tumors. The authors' data showing that 72% of olfactory neuroblastomas were S-100 protein positive and only one was immunoreactive for glial fibrillary acidic protein agree with other published immunohistochemical studies. With only a single exception, each of the 11 neoplasms was labeled with one or more antibodies that detect neuronal cytoskeletal proteins (class III beta-tubulin isotype, microtubule-associated protein-2, neurofilament 200 kD). These immunohistochemical results are complementary to the reported electron microscopic findings of intermediate filaments and microtubules in olfactory neuroblastomas.

Neuroendocrine carcinoma of the colon and rectum. A clinicopathologic, ultrastructural, and immunohistochemical study of 24 cases

To further characterize the clinicopathologic spectrum of colorectal neuroendocrine neoplasia, 24 carcinomas with neuroendocrine differentiation were subtyped as either small cell neuroendocrine, oat cell variant (six cases), small cell neuroendocrine, intermediate variant (16 cases), or moderately differentiated neuroendocrine carcinoma (two cases). Five oat cell variants, 14 intermediate variants, and two moderately differentiated tumors were studied with antibodies to cytokeratin, vimentin, epithelial membrane antigen (EMA), neuron-specific enolase (NSE), chromogranin (CRG), synaptophysin (SYN), neurofilament, S-100 protein, carcinoembryonic antigen (CEA), and Leu-7. All tumors were immunoreactive for cytokeratin and the majority were also positive for EMA and NSE. Positivity for specific neuroendocrine markers was uncommon, with SYN reactivity noted in one oat cell variant and four intermediate variants, and CRG positivity observed in four intermediate variants and one moderately differentiated tumor. Ultrastructural analysis of four oat cell, eight intermediate, and one moderately differentiated tumor revealed neurosecretory-type, dense-core granules in all lesions, except two oat cell variants studied from paraffin-retrieved material. Hepatic and regional lymph node metastases were noted in five of six oat cell, eight of 16 intermediate, and two of two moderately differentiated tumors. Of 17 patients with follow-up (four oat cell, 11 intermediate, and two moderately differentiated tumors), only two individuals were alive after 1 year. There were no detectable differences in survival or response to treatment between morphologic subtypes. The prognosis of colorectal neuroendocrine carcinoma appears worse than for adenocarcinoma of comparable stage. Their distinction is thus warranted, especially in regard to the intermediate variant and moderately differentiated tumors, which may be potentially misinterpreted as forms of adenocarcinoma.

Oocyte retention after follicle luteinization

Indirect evidence supports the existence of the luteinized unruptured follicle syndrome in infertile women. To seek direct evidence of oocyte retention, infertile and normal women were studied in the early and midluteal phase by visual documentation of ovulation stigma, needle aspiration of ovarian follicles, and peritoneal fluid collection for estradiol and progesterone assay. Luteal phase was confirmed by endometrial biopsy (postovulation day 2 to 8). In normal control subjects (n = 16), 25% of test cycles were stigma-negative and no oocytes were recovered. In infertile group (n = 23), 43% of test cycles were stigma-negative. Five oocytes were recovered including one from a stigma-bearing follicle. Peritoneal fluid steroid levels failed to discriminate stigma-positive from stigma-negative cycles in either group. Oocyte retention after luteinization occurs in infertile women.

Use of brefeldin A to define sites of glycosphingolipid synthesis: GA2/GM2/GD2 synthase is trans to the brefeldin A block

Brefeldin A (BFA) induces the rapid redistribution of the Golgi complex into the endoplasmic reticulum (ER), causing the glycoproteins that are retained in the ER to be processed by Golgi enzymes. We have examined the effects of BFA on the synthesis of glycosphingolipids (GSL) to map the intracellular sites of GSL synthesis. In several cultured cell types, BFA inhibited the synthesis of the neutral GSL gangliotriaosylceramide (GA2) and monosialoganglioside GM2 and disialoganglioside GD2, where GD2 is GalNAc(beta 1----4)- [NeuAc(alpha 2----8)NeuAc(alpha 2----3)]Gal(beta 1----4)GlcCer, GM2 lacks the NeuAc(alpha 2----8) unit, and GA2 lacks both NeuAc(alpha 2----8) and NeuAc(alpha 2----3) units. The observed decrease in labeling of GA2, GM2, and GD2 in the presence of BFA was not due either to enhanced degradation of these glycolipids or to shedding of these glycolipids from the cells. In rat liver all three of these glycolipids have been shown by others to be synthesized by the same enzyme, GA2/GM2/GD2 synthase, which catalyzes the addition of N-acetylgalactosamine to lactosylceramide (Lac-Cer), GM3 [NeuAc(alpha 2----3)Gal(beta 1----4)GlcCer], and GD3 [NeuAc(alpha 2----8)NeuAc-(alpha 2----3)Gal(beta 1----4)GlcCer], respectively. Studies with a fluorescent glycolipid analog indicated that BFA redistributed the trans-Golgi stacks into a reticular pattern characteristic of the ER. These studies localize GA2/GM2/GD2 synthase, a key enzyme involved in the synthesis of complex gangliosides, to a compartment late in the intracellular trafficking pathway, which remains functionally distinct from the ER in the presence of BFA.

Expression of "myelomonocytic" antigens in mesotheliomas and adenocarcinomas involving the serosal surfaces

Because of the demonstrated efficacy of Leu-M1 as a discriminant between malignant epithelioid mesothelioma (MEM) and adenocarcinomas involving the serosal surfaces (ACSs), the authors assessed the reactivities of related "myelomonocytic" antigens in this context. Paraffin sections from 41 MEMs and 43 ACSs (pulmonary, "serous surface papillary," and metastatic mammary adenocarcinomas) were evaluated for their expression of Leu-M1, LN1, LN2, and the Mac 387 antigen. Diagnoses were based in each case on the results of conventional histologic and electron microscopic examinations. Leu-M1 was detected only in minute foci of three peritoneal MEMs and was absent entirely in pleural mesotheliomas. Conversely, 38 of 43 ACSs expressed this marker. Three cases of peritoneal MEM and one pleural mesothelioma were multifocally LN2 positive, as were 39 of 43 ACSs. LN1 was the most frequently expressed antigen in MEM, being observed in 18 such tumors (10 pleural; 8 peritoneal); it was also detected in 37 of 43 ACSs. Mac 387 failed to label any of the neoplasms assessed in this series. These results demonstrate similar patterns of "myelomonocytic" antigen expression by diverse ACS and a general absence of Leu-M1 and LN2 in MEM. LN1 and the Mac 387 antigen appear to have no additional value when compared with Leu-M1 and LN2 in the immunohistochemical evaluation of serosal neoplasms.

Malignant epithelioid pleural mesothelioma versus peripheral pulmonary adenocarcinoma: a histochemical, ultrastructural, and immunohistologic study of 103 cases

The distinction between malignant epithelioid pleural mesothelioma (MEPM) and peripheral adenocarcinoma of the lung with pleural invasion (PAL) continues to represent a diagnostic challenge in selected cases. In order to provide comparative data on histologic, histochemical, and immunohistochemical features of these neoplasms, we analyzed 51 ultrastructurally categorized MEPMs and 52 PALs with the periodic acid-Schiff-diastase (PAS-D), mucicarmine, and colloidal iron stains, and a panel of immunohistologic reagents. Antibodies to cytokeratin, vimentin, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), Leu M1, the B72.3 antigen, blood group isoantigens (BGI), placental alkaline phosphatase, amylase, S100 protein, and Clara cell antigen were used, as applied to paraffin sections with the avidin-biotin-peroxidase complex technique. Ultrastructural studies revealed long, branching microvilli in MEPM cells in all cases, with length-to-diameter ratios (LDR) of 10:1 or more. In contrast, PAL manifested short, nonbranching microvilli with LDR of 8:1 or less. Reactivity with PAS-D and mucicarmine stains was strictly confined to PAL, and hyaluronidase-sensitive colloidal iron-positivity was restricted to MEPM. However, only 63% and 41% of these respective neoplasms demonstrated such histochemical reactivity. Immunohistologic results correlated well with electron microscopic classification. All MEPMs and PALs were reactive for cytokeratin; in addition, the majority of tumors in each group expressed EMA, and a minority were reactive for vimentin. In adenocarcinomas of the lung, Leu M1 was observed in all cases, CEA was apparent in 96%, B72.3 labeled 84%, and BGI were present in 67%; all PALs expressed at least two of these determinants, but none was seen in any mesothelioma. The other markers included in this study also were observed in some PAL cases, but not in MEPM. These findings suggest that immunohistology parallels electron microscopy in efficacy in the diagnostic separation of MEPM and PAL. Using antibodies to Leu M1, CEA, and the B72.3 antigen, reactivity for at least two of these three markers appears to exclude a diagnosis of pleural mesothelioma. The other glycoproteinaceous, oncoplacentofetal, and cytoplasmic antigens we studied can be used to reinforce such a determination, since their distribution is confined to adenocarcinomas.

Histiocytoid (epithelioid) hemangioma of the testis. The so-called vascular variant of "adenomatoid tumor"

Adenomatoid tumors are well-recognized neoplasms generally considered to be of mesothelial derivation. We describe an unusual vascular neoplasm that arose in the testis of a 29-year-old and resembled an adenomatoid tumor by light microscopy. An orchiectomy was performed, and the patient is alive and disease-free 3 years later. The 2-cm tumor was composed of small tubules lined by mesothelial-like cells with uniform, vesicular nuclei. However, some lumina contained erythrocytes, and immunohistochemically, the luminal cells reacted with antibodies to vimentin, Factor VIII-related antigen, and Ulex europaeus I lectin but not cytokeratin or epithelial membrane antigen. A cuff of muscle-specific actin-positive cells surrounded the luminal cell layer. This adenomatoid-like vascular neoplasm is more properly interpreted as a histiocytoid (epithelioid) hemangioma. Although some authors have considered microscopically similar lesions to represent a vascular variant of adenomatoid tumor, we prefer to reserve the term "adenomatoid tumor" for microscopically appropriate proliferations that have mesothelial features.

Decreased insulin binding to porcine adipocytes in vitro by beta-adrenergic agonists

The present study was conducted to determine the influence of dibutyryl-cAMP (dbcAMP), epinephrine, ractopamine and clenbuterol on insulin binding to porcine adipocytes. Dibutyryl-cAMP decreased insulin binding to swine adipocytes by 40 and 20% at 1.8 and 25.8 ng insulin/ml, respectively. Ractopamine and clenbuterol directly reduced insulin binding at the low insulin concentration and decreased binding at high insulin concentrations in the presence of adenosine deaminase. Scatchard analysis suggested that the reduction of insulin binding was due to a decrease in receptor number. Epinephrine alone did not influence insulin binding. In the presence of theophylline, epinephrine decreased binding at both low and high insulin concentrations; however, ractopamine plus theophylline decreased binding only at the low insulin concentration. Clenbuterol did not affect insulin binding in the presence of theophylline. Propranolol blocked the inhibitory effect of epinephrine on insulin binding. These beta-adrenergic agonists can inhibit insulin binding and, thus, antagonize insulin action in swine adipocytes.

Beta-tubulin epitope expression in normal and malignant epithelial cells

The expression of a unique beta-tubulin isoform (class III) was monitored in squamous cell carcinoma (SCC) and normal epithelial cells using a monoclonal tubulin antibody called TuJ1. Whole tissue homogenates of SCC, normal tissue, SCC grown in nude mice, and SCC cultured cells were examined using sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot. TuJ1 antibody localization was performed using peroxidase immunostaining on paraffin sections of SCC, normal tissue, nude mouse SCC, and immunofluorescent microscopy of SCC cultured cells. The malignant tissues examined stained positive with TuJ1 and a general beta-tubulin antibody, whereas the normal tissues stained positively only for the general beta-tubulin antibody. TuJ1 epitope expression may be a useful marker for SCCs and may assist in understanding differences between normal and malignant squamous cells.

Effects of ractopamine on adipose tissue metabolism and insulin binding in finishing hogs. Interaction with genotype and slaughter weight

Twenty-four barrows were divided among eight treatments in a 2 x 2 x 2 design to quantify the influence of ractopamine (0 or 20 mg/kg diet) over the final 40 kg of gain on metabolic activity in adipose tissue. Interactions with genotype (Hampshire cross or Landrace cross) and slaughter weight (100 or 127 kg) were investigated also. Backfat was removed at slaughter and rates of lipolysis and fatty acid synthesis (FS), activities of malic enzyme (ME) and fatty acid synthetase (FAS), and insulin binding to adipocytes were assessed. Adipocytes from ractopamine-fed pigs were less sensitive (EC50 increased 90%) and had a lower maximum lipolytic response (40%) to ractopamine stimulation. Rates of basal and insulin-stimulated FS were decreased 40% in ractopamine-fed pigs and were reflected in lower activities of ME (50%) and FAS (15%). Breed and slaughter weight had no consistent influence on the ractopamine response. Landrace-cross pigs had greater insulin binding capacity (30-60%) whether data were expressed on a cell or surface area basis. Ractopamine feeding did not consistently affect insulin binding capacity. Results suggest that ractopamine interacts in vivo with the beta-adrenergic receptor of swine adipocytes, decreasing lipogenic capacity and diminishing responsiveness to beta-adrenergic stimulation.

Carcinoma arising in oncocytic Schneiderian papilloma

Two men aged 54 and 73 years, respectively, had oncocytic Schneiderian papilloma (OSP) containing synchronous carcinoma at the time of first biopsy. In both cases, invasive carcinoma involved a small proportion of excised tissue and was in continuity with dysplastic surface epithelium. Our cases document that the epithelial component of OSP can undergo malignant transformation. The focal involvement of OSP with carcinoma underscores the need to examine all excised tissue microscopically.

Sensitivity of lipolysis and lipogenesis to dibutyryl-cAMP and beta-adrenergic agonists in swine adipocytes in vitro

The sensitivities of lipolysis and fatty acid synthesis to dibutyryl-cAMP (dbcAMP), epinephrine, ractopamine and clenbuterol were quantified in vitro using porcine adipocytes. Insulin-stimulated lipogenesis showed a biphasic response to dbcAMP, with increased rates at low concentrations and decreased (55%) rates at higher concentrations of dbcAMP. In the absence of insulin, lipogenesis was inhibited 78% by dbcAMP. In the presence of adenosine deaminase or theophylline, all three beta-adrenergic agonists inhibited basal lipogenesis, but only epinephrine and ractopamine inhibited insulin-stimulated lipogenesis. The relationship between suppressed lipogenesis and enhanced lipolysis in response to dbcAMP and the beta-agonists revealed that 1) basal lipogenesis was more sensitive to inhibition than was the stimulation of lipolysis, 2) sensitivity differences were magnified if adenosine deaminase was present and 3) insulin decreased adipocyte sensitivity to the inhibitory effects of dbcAMP and the beta-adrenergic agonists. These results indicate that the relative sensitivities of lipogenesis and lipolysis to beta-adrenergic stimulation can be modified by adenosine and insulin. Furthermore, adenosine and insulin antagonize beta-adrenergic responses, in part, by cAMP-independent mechanisms.

Clear cell tumor of the lung. A clinicopathologic, immunohistochemical, and ultrastructural study of eight cases

We studied eight clear cell tumors of the lung (CCTL) to better define their clinical, immunohistochemical, and ultrastructural features, and to clarify their distinction from other neoplasms, particularly metastatic renal cell carcinoma. Patients ranged in age from 31 to 67 years (mean, 51 years). Seven patients had clinically benign, asymptomatic lesions measuring less than 2 cm in diameter that were devoid of necrosis. The eighth patient had a symptomatic, partially necrotic CCTL 4.5 cm in diameter that metastasized to the liver and peritoneum; the patient died of tumor 17 years after diagnosis. Ultrastructural study of seven CCTL showed interdigitating cell processes (all cases), primitive cell junctions (five of seven cases), intracytoplasmic glycogen (all cases), and rare dense core granules (two of seven cases). Immunohistochemically, paraffin-embedded sections from all eight CCTL were negative for cytokeratin (CK), epithelial membrane antigen (EMA), chromogranin, and vimentin. Focal staining was seen for S-100 protein (three of eight cases), neuron-specific enolase (three cases), synaptophysin (one case), and Leu 7 (one case). Although these findings suggest that at least some CCTL exhibit neuroendocrine differentiation, the tumor's histogenesis remains uncertain. Of more practical importance, the combined absence of CK, EMA, and vimentin in formalin-fixed, paraffin-embedded CCTL virtually precludes confusion with renal cell carcinoma. Although traditionally considered benign, CCTL larger than 2 cm that are symptomatic, and focally necrotic should be regarded as potentially malignant neoplasms.

Insulin binding to mouse adipocytes exposed to clenbuterol and ractopamine in vitro and in vivo

Insulin binding to mouse adipocytes was measured after in vitro (30 min) and in vivo (5 days) exposure to clenbuterol and ractopamine. At 10(-6) M, both agonists decreased insulin binding by 20-30% after a 30 min preincubation at each insulin concentration between 1 and 25 ng/ml. Binding was not decreased if propranolol was present. Scatchard plots suggested that decreased binding was due to a decrease in insulin receptor concentration. Insulin binding was decreased approximately 10% at agonist concentrations as low as 10(-13) M, but binding was not further decreased until concentrations exceeded 10(-9) M. Rate of gain was increased 2-fold by clenbuterol (10 mg/liter of drinking water) and 50% by 500 mg ractopamine/liter, but not by 50 mg ractopamine/liter. Clenbuterol and ractopamine (500 mg/liter) decreased fat pad weight but only clenbuterol increased hind limb muscle mass. Insulin binding following in vivo administration was not influenced by ractopamine at 50 mg/liter, but tended to be increased by clenbuterol and ractopamine at 500 mg/liter. The disparity in results between administering the beta-agonists in vitro or in vivo suggests that counter regulatory factors influenced insulin binding capacity in vivo. Results indicate that ractopamine and clenbuterol can decrease insulin binding to adipocytes but the relevance of this response to decreased fat accretion is not clear.

Determination of the affinity of ractopamine and clenbuterol for the beta-adrenoceptor of the porcine adipocyte

Dissociation constants (Kd) of ractopamine and clenbuterol for the swine adipocyte beta-adrenergic receptor were estimated from competition studies with epinephrine for the stimulation of lipolysis. Both compounds competitively inhibited epinephrine-stimulated lipolysis in the absence of adenosine deaminase. Three methods for estimating Kd values were used and similar estimates were obtained with each method. Ractopamine and clenbuterol showed greater affinity for the beta-receptor than did epinephrine and had similar Kd values of 1 to 2 x 10(-7) M. The low capacity of ractopamine and clenbuterol to stimulate lipolysis in vitro does not result from poor coupling to the beta-receptor. Ractopamine and clenbuterol may be considered partial agonists, possessing high affinity for the beta-adrenoceptor but exhibiting a relative ineffectiveness for adenylate cyclase activation.

Adipose tissue lipogenesis in growing steers adapted to different levels of feed intake

The association between feed intake and lipogenic activity in adipose tissue was investigated in growing cattle. Twenty-five 300-kg steers were allotted by BW to one of five levels of intake of a single high-energy corn-corn silage-based diet. Steers were adapted to diets over 4 wk and intakes were adjusted weekly to achieve steady but varying rates of growth. Daily intakes (% of BW) averaged .92, 1.15, 1.64, 2.28 and 2.69 and resulted in growth rates over the final 3 wk of -.28, .07, .71, 1.67 and 1.69 kg/d, respectively. Lipogenic activities in biopsied tissue and circulating concentrations of glucose and insulin were lowest at maintenance feeding and below but increased linearly (P less than .01 for lipogenesis; P less than .1 for glucose and insulin) as intake increased above maintenance. Mean minimal and maximal rates (mumoles.-min(-1).10(6) cells(-1)) or concentrations were fatty acids synthesis ([14C]acetate---fatty acid)), .065 and .723; fatty acid synthetase (NADPH oxidized), .266 and 2.97; lipoprotein lipase (fatty acid released), .048 and .359; glucose (mg/dl), 60.4 and 70.7 and insulin (ng/ml), .70 and 1.66. In a preliminary study with the same 25 steers fed ad libitum, nearly 25% of the variability in adipose tissue lipogenesis was accounted for by variation in feed intake. Results indicate that activities of lipogenic enzymes and lipogenic capacity in growing steers coordinately adapt to the level of feed consumed and that nutrient availability and(or) insulin concentrations may participate in this adaptation.

Effect of suppression of prolactin secretion on adipose lipogenesis in the postpartum beef cow

Effects of inhibiting prolactin secretion and of calf removal at 3 d postpartum on the lipogenic capacity of s.c. adipose tissue were investigated in postpartum beef cows. The rate of fatty acid synthesis (SYN) from [1-14C]acetate and the activity of fatty acid synthetase (FAS) were assessed on adipose tissue obtained by biopsy at 1, 2, 4, 8 and 10 wk postpartum. Administration of bromocriptine (BR; a drug that suppresses prolactin secretion in rats) between d 7 and 42 postpartum decreased average serum prolactin concentrations nearly 90%, but BR had no effect on lipogenic rates at any week compared to control (CO) cows. Rates of SYN (nmol acetate.min-1.g-1 tissue) increased linearly in CO and BR cows from a nadir of 3.1 at wk 1 to 19.3 by wk 8. Within CO and BR, cows with the greater energy intake relative to requirements for lactation (energy balance) had the faster rates of recovery of SYN. Cows whose calves were weaned early (3 d) showed rapid early increases in SYN, reaching an average maximum rate of 46.2 by wk 2. Activity of FAS generally followed a pattern similar to that of SYN for all groups. Results indicate that prolactin is not responsible for low rates of postpartum lipogenesis in s.c. adipose tissue and that energy intake influences the rate of recovery.

Acute effects of beta-adrenergic agonists on porcine adipocyte metabolism in vitro

Backfat was obtained at slaughter from market weight hogs to study the acute effects of clenbuterol (CB), ractopamine (RAC) or epinephrine (EPI), in the presence and absence of theophylline (THEO) or adenosine deaminase (ADA), on rates of lipolysis and fatty acid synthesis in vitro. Only EPI increased lipolytic rate in the absence of THEO or ADA. In the presence of THEO or ADA, RAC and CB were lipolytic, although CB had a lower maximal response. With THEO present, RAC and EPI increased lipolysis with a similar potency and responsiveness. Lipolytic responses from all agonists were prevented by propranolol. Insulin stimulated glucose incorporation into fatty acids 50 to 100%; stimulated rates were not influenced by any agonist, either alone or in the presence of ADA. When THEO was present, EPI and RAC inhibited fatty acid synthesis approximately 50%. Clenbuterol was not inhibitory under any conditions. Results indicate that, under appropriate conditions, beta-adrenergic agents increase lipolysis and decrease lipogenesis in porcine adipocytes. Combined evidence suggests that lipolysis is more sensitive to beta-adrenergic stimulation than is insulin-stimulated lipogenesis. Finally, RAC and CB possess only partial agonist activity relative to EPI, CB being least active.

The presence and estrogen control of immunoreactive calbindin-D9k in the fallopian tube of the rat

The present study was undertaken to localize and investigate the endocrine control of immunoreactive 9K calbindin-D9k in the fallopian tube (oviduct) of the rat. Rat fallopian tubes were excised with the uterus, immediately fixed by freeze-substitution, and processed for immunoperoxidase staining. Staining employed a rabbit antiserum against purified rat intestinal calbindin-D9k and the streptavidin-biotin technique. Calbindin-D9k immunoreactivity was localized to luminal epithelial cells of the fallopian tube of mature rats, with no staining observed in other tissue layers of the tube. Epithelial cells in both the isthmus and the ampulla were positive for calbindin-D9k. In weanling rats, which have little ovarian function but high levels of 1,25-dihydroxyvitamin D, no immunoreactive calbindin-D9k was observed in any part of the tube. However, after daily injections of estradiol (6 micrograms/day) for 3 days, intense staining was observed in the epithelial cells of the immature rat fallopian tube. Progesterone treatment (1 mg/day for 3 days) of immature rats had no effect on calbindin-D9k in fallopian tube. The lumen of the fallopian tube (oviduct) is the key location for fertilization, a process that requires a narrowly defined concentration of extracellular calcium. By analogy to the intestine, calbindin-D9k may play a role in the transcellular movement of calcium across the fallopian tube epithelium in the fallopian tube lumen.

"Undifferentiated" neoplasms of the sinonasal region: differential diagnosis based on clinical, light microscopic, immunohistochemical, and ultrastructural features

Sinonasal neoplasms and neoplasm-like proliferations composed of light microscopically poorly differentiated or undifferentiated, small- to medium-sized cells cause considerable diagnostic confusion. Lesions in this category include lymphoepithelioma (undifferentiated carcinoma), olfactory neuroblastoma, small-cell undifferentiated (oat cell) carcinoma, sinonasal undifferentiated carcinoma, malignant melanoma, pituitary adenoma, lymphoid hyperplasia, malignant lymphoma, plasmacytoma, lymphomatoid granulomatosis, rhabdomyosarcoma, mesenchymal chondrosarcoma, small cell osteosarcoma, Ewing's sarcoma, and synovial sarcoma. Many of these lesions can be definitively diagnosed based on light microscopic features alone, but, in some instances, additional techniques such as immunohistochemistry are of value. The authors review the pertinent clinicopathologic features of the above lesions, with emphasis on light microscopic, immunohistochemical, and ultrastructural features of particular utility in differential diagnosis.

Vascular adrenal cysts. A clinicopathologic and immunohistochemical study of endothelial and hemorrhagic (pseudocystic) variants

Three endothelial cysts and five hemorrhagic cysts (pseudocysts) arose in the adrenal glands of seven patients aged 23-73 years. Four patients were male and three were female. Five were symptomatic and gave abdominal pain as their chief complaint. Endothelial cysts were collapsed or filled with serous fluid, multiloculated, had an endothelial lining, and often contained adrenal cortex in their outer walls. The endothelial lining reacted only weakly for Factor VIII-related antigen (FVII-RAg), but it stained strongly for collagen type IV (C-IV). The lack of hemorrhage and the FVIII-RAg/C-IV staining pattern in endothelial cysts suggest lymphatic differentiation. Hemorrhagic cysts were spherical, firm masses containing clotted blood and hyalinized thrombus with attenuated adrenal cortex in the outer fibrous wall. Islands of intact cortical cells were present deep within the thrombi of four hemorrhagic cysts. Three of five hemorrhagic cysts stained strongly for FVIII-RAg and C-IV in irregular vascular channels of the attenuated cortex and within the cyst contents. These channels suggest that at least some hemorrhagic cysts arise when hemorrhage occurs in a preexisting blood vascular anomaly. Entrapment of cortical islands by extravasated blood in hemorrhagic cysts may be misdiagnosed as necrotic cortical neoplasm. To avoid confusion, one must recognize the normality of the entrapped cortical cells, identify an intrinsic vascular anomaly, and distinguish thrombus from necrotic tumor.