High level of ATP citrate lyase expression in human and rat pancreatic islets.

A comparison of an enzyme's level in pancreatic islets with its level in other body tissues can give clues about the importance of a metabolic pathway in the islets. ATP citrate lyase plays a key role in the pyruvate citrate shuttle, as well as for the synthesis of short chain acyl-CoAs and lipid, and its level in human and rat pancreatic islets relative to other tissues has not been previously reported. We compared the level of ATP citrate lyase mRNA and enzyme activity in pancreatic islets of humans and rats and the INS-1 832/13 cell line to levels in liver, a lipid synthesizing organ, and also kidney. The mRNA level was much higher in human islets and rat islets than in liver and kidney of the same genus and the enzyme activity was 8-fold and 12-fold higher in islets of humans and rats, respectively, compared to liver of the same genus. These data support other evidence that indicates ATP citrate lyase is important for the pyruvate citrate shuttle and lipid synthesis in insulin secretion.

18F-labeled resin microspheres as surrogates for 90Y resin microspheres used in the treatment of hepatic tumors: a radiolabeling and PET validation study.

(90)Y-labeled resin microspheres (SIR-Spheres) are currently used to treat patients with primary and metastatic solid liver tumors. This treatment is typically palliative since patients have exhausted all other standard treatment options. Improving the quality of life and extending patient survival are typical benchmarks for tracking patient response. However, the current method for predicting microsphere biodistributions with (99m)Tc-labeled macroaggregated albumin (MAA) does not correlate well with patient response. This work presents the development of a new (18)F-labeled resin microsphere to serve as a surrogate for the treatment microsphere and to employ the superior resolution and sensitivity of positron emission tomography (PET). The (18)F microsphere biodistributions were determined in a rabbit using PET imaging and histological review. The PET-based uptake ratio was shown to agree with the histological findings to better than 3%. In addition, the radiolabeling process was shown to be rapid, efficient and relatively stable in vivo.

Circulating tumor cells in murine myeloma.

BALB/c mice bearing subcutaneous ADJ-PC5 myelomas had hematologic findings suggestive of a preleukemic syndrome: thrombocytopenia, anemia, leukocytosis, and megakaryocytic hyperplasia. Six BALB/c myelomas were successfully transplanted sc by fragments or cell suspensions of spleens from mice bearing a subcutaneous tumor, though typical myeloma cells were difficult to visualize by light microscopy in these spleens. The fidelity of transmission of the ADJ-PC5 myeloma by this procedure was shown by the retention of idiotypic specificity of the immunoglobulin produced by the tumor in a radioimmunoassay. The tumorigenic cell that homed to the spleen was apparent as early as 8 days after sc transplantation of the myeloma. The spleens of tumor-bearing mice, however, could destroy or suppress the expansion or growth of a limited number of cells that had migrated to the spleens. Tumorigenic cells present in the peripheral circulation constituted 2-3% of the leukocytes. These cells, however, had reduced levels of the murine myeloma viral and cell-associated antigens, were difficult to detect by an indirect immunofluorescence assay, and did not rapidly divide in this environment, as indicated by the very low number of cells detected by autoradiography.

High activity of mitochondrial glycerol phosphate dehydrogenase in insulinomas and carcinoid and other tumors of the amine precursor uptake decarboxylation system.

The activity of the mitochondrial glycerol phosphate dehydrogenase (EC 1.1.99.5), the enzyme unique to the glycerol phosphate hydrogen shuttle, was measured in normal human tissues and tumors and compared with the activity of succinate dehydrogenase, another enzyme that transfers electrons to ubiquinone at site II of the electron transport chain. Six of 7 insulinomas and 10 of 12 carcinoid tumors showed high glycerol phosphate dehydrogenase activity. The activity was also increased in 3 of 4 gastrinomas, 2 paraganglionomas, 1 of 4 thyroid nodules, and 1 parathyroid tumor. These tissues belong to the amine precursor uptake decarboxylation system. The activity of glycerol phosphate dehydrogenase was generally unremarkable in non-amine precursor uptake decarboxylation system tumors and in normal tissues studied. However, 1 of 2 breast carcinomas, 1 submandibular tumor, and 2 of 3 melanomas were enriched in glycerol phosphate dehydrogenase activity. In general, succinate dehydrogenase activity exceeded that of glycerol phosphate dehydrogenase in all tissues except some of the tissues in which glycerol phosphate dehydrogenase activity was high. Normal tissues, such as the pancreatic beta-cell, which aerobically metabolize glucose rapidly utilize the glycerol phosphate shuttle to oxidize the large amount of NADH formed from glucose metabolism in the cytosol. Whether this is the reason for the enriched activity of the glycerol phosphate dehydrogenase in certain amine precursor uptake decarboxylation system tumors is unknown.

Some determinants of quality and yield in the isolation of adult heart cells from rat.

We investigated the effect of changes in perfusate substrate and Ca content on the quality and yield of isolated adult rat heart cells. When 1 mM Ca was added to the recirculating perfusate 15 min after collagenase addition, the ATP level of cells in the heart 15 min later, and their morphology in histological section, was no different from when no Ca was added back. The cells subsequently isolated were of similar yield, but a greater percentage were rod-shaped, compared with cells isolated without Ca restoration to the perfusate. Increased yield could be obtained by including substrates in the perfusate in addition to glucose. Either fatty acids or amino acids were effective. We conclude that: (1) all cells in the heart are Ca tolerant at the end of enzyme perfusion; (2) the presence of substrates in addition to glucose can help cells survive the isolation process.

Increased mitochondrial glycerol phosphate dehydrogenase activity in insulinomas of two hypoglycemic infants.

The activities of flavin-linked, mitochondrial glycerol phosphate dehydrogenase in islet cell adenomas from two infants were 8 and 16 times higher than those in their uninvolved pancreases. The enzyme in the insulinomas, but not that in the nearby pancreases, was inhibited by diazoxide, which is a known inhibitor of insulin secretion in vitro and in vivo. These results provide preliminary evidence that the enzyme may be used as an adjunct to histology for identifying human insulin-secreting tissues. Its sensitivity to diazoxide adds specificity to the test. Taken together with previous work with animal pancreatic islets, the results of the present study suggest that the glycerol phosphate shuttle plays an important role in stimulus-secretion coupling in the pancreatic beta-cell.

Pseudo-Gaucher cell in IgMk plasmacytoid lymphoma.

Cells resembling those of Gaucher's disease were found on imprints of a lymph node from a patient with a plasmacytoid lymphoma. These cells contained nonspecific esterase, and electron-dense crystal-like structures. Associated plasma cells stained positively with anti-kappa and anti-mu sera but few macrophages were stained. The resemblance of these macrophages to Gaucher cells was due to the crystal-like inclusions that probably represented altered immunoglobulin.

Minimal deviation melanoma with epidermotropic metastases arising in a congenital nevus.

A congenital nevus removed from a 20-year-old woman was found to contain a minimum deviation melanoma. Subsequently, there were multiple nodular recurrences in the region of the excision as well as in the grafted skin. Microscopically the recurrent lesions closely resembled the original nevus, including the junctional activity and even the grafted skin. Lymph node metastasis occurred 5 1/2 years after excision of the nevus. This is the first report of a minimal deviation melanoma arising in a congenital nevus with epidermotropic metastases.

Malignant nerve sheath tumor containing endocrine cells.

A malignant nerve sheath tumor occurred in the thigh of a 29-year-old man who had the stigmata of von Recklinghausen's neurofibromatosis. Chondroid foci, rhabdomyoblasts, and mucus-containing acini were identified in the tumor. Argyrophil cells and somatostatin-immunoreactive cells were present in acinar epithelium. Endocrine type granules were found in epithelial cells on ultrastructural examination. This is an example of a so-called "glandular schwannoma" and is unique in that it contained somatostatin-immunoreactive cells. A neural crest derivation is suggested for this complex tumor.

Metastasizing atrial myxoma.

Tumors that were identical in morphology to a previously excised atrial myxoma were found in the choroid plexus and the scapula of a 46-year-old woman 8 and 10.5 years, respectively, after cardiac surgery. Ultrastructurally the scapular lesion resembled previously reported atrial myxomas. This case demonstrates that atrial myxoma is a true neoplasm capable of metastatic spread despite its slow growth and innocuous histologic appearance.

Immunohistochemical detection of chromogranin and neuron-specific enolase in pancreatic endocrine neoplasms.

Twenty pancreatic endocrine tumors and one duodenal somatostatinoma were stained with polyclonal antisera against eight hormones, neuron-specific (NSE), and with a monoclonal antibody against the endocrine granule protein chromogranin. Silver staining was performed on all tumors with the Grimelius method. All the tumors and all cells in the normal pancreatic islet showed NSE immunoreactivity. Chromogranin immunoreactivity was found predominantly in the glucagon cells of normal islets, in one glucagonoma, four gastrinomas and in 10 tumors associated with multiple hormonal production, but not in five insulinomas or in one somatostatinoma. Grimelius reactivity was identical to chromogranin immunoreactivity in all cases except that more cells in the tumors and in the normal islets were positive for chromogranin. Both chromogranin and NSE were detected in a metastasized pancreatic endocrine tumor which had metastasized to a peripancreatic lymph node. The metastatic tumor failed to stain with antisera to all eight hormones. These results indicate that chromogranin and NSE are excellent general markers for pancreatic endocrine tumors and that the Grimelius stain and other related argyrophilic reactions may involve binding to chromogranin.

Use of In-111 pentetreotide scintigraphy in the diagnosis of a midgut carcinoid causing Cushing's syndrome.

A 57-year-old man presented with clinical features of hypercortisolism and was diagnosed with ACTH-dependent Cushing's syndrome. Biochemical testing showed partial suppression of urinary free cortisol with high dose dexamethasone. Initial computed tomography (CT) of the chest and abdomen, and magnetic resonance imaging of the pituitary were negative. In-111 pentetreotide scintigraphy with single photon emission computerized tomography revealed two 'hot' lesions in the abdomen which were then confirmed by subsequent directed thin-slice abdominal CT and small bowel barium study. At surgery, two segments of ileum, adjoining mesentery and lymph nodes were resected. Histopathology was consistent with a malignant carcinoid tumor of the ileum which stained intensely for ACTH. Plasma ACTH, and serum and urinary cortisol normalized postoperatively. To our knowledge, this is the first reported case of ileal carcinoid tumor causing Cushing's syndrome with premortem diagnosis. Another unique feature of this case is that In-111 pentetreotide scan provided the decisive clue to localization of the tumor.

Donor-derived human leukocyte antigen class I proteins in the serum of heart transplant recipients.

BACKGROUND: Human leukocyte antigen class I proteins are expressed on most cell types in all organ allografts but are constitutively secreted only by certain organs, for example, the liver. We hypothesized that detectable levels of donor-derived human leukocyte antigen proteins would be released from transplanted cardiac allografts only when the allograft was immunologically stimulated, that is, during rejection and perhaps during viral infection. If so, then the release of donor human leukocyte antigen might be a noninvasive monitor of these events. METHODS: We used an enzyme-linked immunosorbent assay to detect donor-derived human leukocyte antigen-A2 in the serum of 21 human leukocyte antigen-A2 negative recipients of human leukocyte antigen-A2-positive heart transplants. The level of donor human leukocyte antigen-A2 during the first 100 days after transplantation was correlated with the clinical status of the patient. RESULTS: We found little or no donor human leukocyte antigen in the serum of heart transplant recipients whose postoperative clinical course was unremarkable for infection or rejection. We did find donor-derived human leukocyte antigen in the serum of heart transplant recipients transiently in the week immediately after transplantation, continuously from patients in whom chronic rejection was developing, during cytomegalovirus infection, and during some, but not all, acute rejection episodes as determined by endomyocardial biopsy. CONCLUSIONS: These findings are consistent with the hypothesis that the donor human leukocyte antigen serum level reflects vascular diseases, rather than myocardial disease in the transplanted heart. Therefore, the serum level of donor human leukocyte antigen cannot be used as a monitor of cellular infiltration and myocyte damage as currently assessed by endomyocardial biopsy but may be an early indicator of the development of vascular disease such as chronic rejection.

Carcinoid tumour of the uterine cervix.

A carcinoid tumour of the cervix in a 64-year-old woman is described. It is the first time that this rare tumour has been associated with carcinoma-in-situ.

Tertiary hyperparathyroidism after renal transplantation: surgical strategy.

BACKGROUND: An analysis of our experience with tertiary hyperparathyroidism (III HPT) in renal transplantations between 1981 and 1996 was reviewed to examine a variety of laboratory and clinical variables in this population. METHODS: A total of 3233 kidney transplantations were performed; 48 patients underwent parathyroidectomy for III HPT. Five patients were excluded from analysis due to the development of renal dysfunction. The index 43 patients were divided into two groups. Group I consisted of 31 patients (72%) with either enlargement of all parathyroid glands (n = 26) or 3/4 gland enlargement (n = 5). These patients were assumed to have hyperplasia and underwent subtotal parathyroidectomy or total parathyroidectomy. Group II consisted of 12 patients (28%) with single (7/12; 58%) or two-gland enlargement (5/12; 42%). Group II patients underwent resection of only the enlarged glands. RESULTS: Laboratory and clinical parameters showed no difference between the groups during long-term follow-up. Most patients in groups I and II were eucalcemic after parathyroidectomy. However, postoperative hypercalcemia and hypocalcemia did occur in group I (mean postoperative calcium: group I = 9.29 +/- 0.63 mg/dL; group II = 9.42 +/- 0.58 mg/dL). CONCLUSIONS: Four gland parathyroid enlargement is a frequent finding in III HPT, although asymmetric enlargement can occur. Histologically, this represents sporadic adenomas and asymmetric hyperplasia. Intraoperative findings should dictate surgical strategy; with asymmetric enlargement only the enlarged parathyroid glands should be resected.

Macrophage depletion alters vein graft intimal hyperplasia.

BACKGROUND: The principal cause of vein graft failure is intimal hyperplasia (IH); however, its etiology remains unclear. In a rat model of vein graft IH we have observed prolonged transmural macrophage infiltration, leading us to hypothesize that these cells regulate IH. To test this, we used liposome-encapsulated dichloromethylene bisphosphonate (L-Cl2MBP) to deplete rat macrophages and observed the effects on IH. METHODS: Epigastric vein-to-femoral artery grafts were microsurgically placed in male Lewis rats that had been intravenously injected with L-Cl2MBP, phosphate-buffered saline solution liposomes, or phosphate-buffered saline solution alone 2 days before surgery. Several animals in each group received a second equivalent dose at 2 weeks. Grafts, contralateral epigastric veins, spleens, and livers were harvested at 1, 2, and 4 weeks for histologic examination, immunohistochemistry, and transmission electron microscopy. RESULTS: In the L-Cl2MBP-treated animals splenic and hepatic macrophages were greatly reduced, confirming the efficacy of the agent. At 1 to 2 weeks graft macrophages were significantly decreased, and there was a trend toward decreased IH. At 4 weeks macrophage numbers were normal and IH development had resumed. In contrast, the 4-week grafts treated with 2 doses of L-Cl2MBP had fewer macrophages and displayed severely attenuated IH. CONCLUSIONS: The results indicate a suppression of IH as macrophages are depleted, with a resumption of the process as macrophages repopulate the graft.

Penile Merkel cell carcinoma.

Merkel cell carcinoma of the genitalia is very rare and to date has been found only in vulvar mucosa. We describe an aggressive Merkel cell tumor in the frenulum of the penis with lymph node metastases, local recurrence, and eventually widespread dissemination. The primary tumor was associated with discontiguous squamous cell carcinoma in situ. This is the first report of Merkel cell (neuroendocrine) carcinoma in this anatomic site.

Recurrent ischemic strokes in a patient with Medtronic-Hall prosthetic aortic valve and valve strands.

Fine strands associated with prosthetic heart valves have been demonstrated with transesophageal echocardiography, but the pathologic identity of these strands is unclear. A case of a man with a prosthetic aortic Medtronic-Hall valve with prominent valve strands and recurrent strokes is discussed. The patient underwent valve replacement surgery, and histopathologic examination of the strands identified them as Lambl's excrescences.

mRNAs for PRPs, statherin, and histatins in von Ebner's gland tissues.

A search was made for expression of genes for proline-rich proteins (PRPs) and other salivary-type proteins, including statherin and histatins, in taste-bud tissues of mice and primates because of previous genetic findings in mice (Azen et al., 1986) that Prp and taste genes for certain bitter substances are either the same or closely linked. Taste-bud tissues and other tissues were tested for specific mRNAs with labeled DNA probes by Northern blotting and in situ hybridization. It was found that PRP mRNAs were present in von Ebner's glands of mice and macaques, and that there was a much greater degree of PRP mRNA induction in mouse parotid (16-fold) than in von Ebner's gland (two-fold) after in vivo isoproterenol stimulation. This difference may be due, in part, to differences in autonomic nerve innervation. Statherin and histatin mRNAs were found in macaque taste-bud tissues containing von Ebner's gland, and statherin protein was found in human von Ebner's gland by immunohistochemistry. The finding of PRP gene expression in von Ebner's gland, whose secretions have been suggested to play a role in taste stimulation, adds further support to a possible function of PRPs in bitter tasting. The possible functions of statherin and histatins in von Ebner's gland secretions may be related to statherin's regulation of salivary calcium and histatins' antibacterial and antifungal properties.

Tissue distribution of RNAs for cystatins, histatins, statherin, and proline-rich salivary proteins in humans and macaques.

The tissue distribution of the mRNAs for a number of salivary proteins [proline-rich proteins (PRPs), statherin, cystatins, and the histatins] has been examined in humans and macaques in order to investigate their possible functions and tissue-specific regulation. We have shown that PRP RNAs (0.8-1.5 kb) are expressed in human and rhesus parotid and submandibular glands, and in the human bronchus. The genes for the acidic and basic PRPs are differentially regulated in these tissues. RNAs for acidic PRPs are predominantly expressed in the submandibular gland, for basic PRPs in the respiratory tract, and for both acidic and basic PRPs in the parotid gland. Protein studies of secretions from these tissues confirm the RNA results. Statherin RNA (0.65 kb) was detected in human and rhesus parotid and submandibular glands and the human bronchus, as well as in rhesus lacrimal glands. Statherin was found by tissue immunoperoxidase staining in the serous cells of respiratory tract submucosal glands, which is the same location for the synthesis of PRPs. Several cystatin RNAs (0.8-1.3 kb) were differentially expressed in human parotid glands, submandibular glands, and the bronchus, and in lacrimal glands from both rhesus and cynomolgus macaques. RNAs (0.6 kb) for the histatins were found only in parotid and submandibular glands. Thus, it appears that PRPs, statherin, and cystatins may play a broader role in the physiology of biological fluids and secretions than previously suspected, since they are found in secretions other than saliva. However, the functions of the histatins are restricted to saliva. These studies also pose some interesting questions regarding the differential expression of these genes in a variety of secretory tissues.