Epitheliocystis in lake trout Salvelinus namaycush (Walbaum) is associated with a β-proteobacteria

Lake trout Salvelinus namaycush (Walbaum) raised for stocking experienced yearly (2011-13) winter epizootics of epitheliocystis. Affected fish were dispersed on the bottom of the tank, had decreased feed and fright response, and mortality often reached 40%. Peak mortality occurred within 3 weeks of the appearance of clinical signs, and outbreaks typically lasted 6 weeks. Affected fish had no gross lesions but histologically had branchial epithelial necrosis and lamellar hyperplasia, with small to large numbers of scattered epithelial cells containing 10- to 20-μm inclusions. A longitudinal study was undertaken of one annual outbreak, and lamellar hyperplasia was most closely associated with mortality. The number of inclusions was statistically greater (P < 0.05) before and during peak mortality, but inclusions were present in low numbers before clinical signs occurred. Results of histochemical staining, immunohistochemistry and transmission electron microscopy supported the presence of a β-proteobacteria rather than a Chlamydiales bacterium within inclusions. PCR primers to identify Chlamydiales did not give consistent results. However, the use of universal 16S rDNA bacterial primers in conjunction with laser capture microdissection of inclusions demonstrated that a β-proteobacteria was consistently associated with affected gills and is more likely the cause of the disease in lake trout.

Cellular, molecular and immunological mechanisms in the pathophysiology of vein graft intimal hyperplasia

Coronary artery disease, leading to myocardial infarction and ischaemia, affects millions of persons and is one of the leading causes of morbidity and mortality worldwide. Invasive techniques such as coronary artery bypass grafting are used to alleviate the sequelae of arterial occlusion. Unfortunately, restenosis or occlusion of the grafted conduit occurs over a time frame of months to years with a gradual reduction in patency, especially in vein grafts. The events leading to intimal hyperplasia (IH) formation involve numerous cellular and molecular components. Various cellular elements of the vessel wall are involved as are leucocyte-endothelial interactions that trigger the coagulation cascade leading to localized thrombus formation. Subsequent phenotypic modification of the medial smooth muscle cells and their intimal migration is the basis of the lesion formation that is thought to be propagated by an immune-mediated reaction. Despite intense scrutiny, the pathophysiology of IH remains an enigma. Although several growth factors, cytokines and numerous other biomolecules have been implicated and their relationship to prohyperplasia pathways such as the phosphatidyl-inositol 3-kinase (PI3K)-Akt pathway has been established, many pieces of the puzzle are still missing. An in-depth understanding of early vein graft adaptation and progression is necessary to improve the long-term prognosis and develop more effective therapeutic measures. In this review, we have critically evaluated and summarized the literature to elucidate and interlink the numerous established and emerging factors that play a key role in the development of IH leading to vein graft restenosis.

Primary hyperparathyroidism and heart disease--a review

Primary hyperparathyroidism (pHPT), caused by solitary parathyroid adenomas in 85% of cases and diffuse hyperplasia in most of the remaining cases, overproduces parathyroid hormone (PTH), which mobilizes calcium to the blood stream. Renal stones, osteoporosis and diffuse symptoms of hypercalcaemia, such as constipation, fatigue and weakness are well-known complications. However, in Western Europe and North America, patients with pHPT are nowadays usually discovered during an early, asymptomatic phase of the disease. It has been reported that patients suffering from symptomatic pHPT have increased mortality, mainly due to an overrepresentation of cardiovascular death. pHPT is reported to be associated with hypertension, disturbances in the renin-angiotensin-aldosterone system, and structural and functional alterations in the vascular wall. Recently, studies have indicated an association between pHPT and heart disease, and studies in vitro have produced a number of theoretical approaches. An increased prevalence of cardiac structural abnormalities such as left ventricular hypertrophy (LVH) and valvular and myocardial calcification has been observed. Associations have been found between PTH and LVH, and between LVH and serum calcium. LV systolic function does not seem to be affected in patients with pHPT, whereas any influence on LV diastolic performance needs further evaluation. The aim of this review is to clarify the connection between pHPT and cardiac disease.

Vascular endothelial growth factor (VEGF)-eluting stents: in vivo effects on thrombosis, endothelialization and intimal hyperplasia

Local drug delivery by stent can reduce in-stent restenosis. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen. After stenting, the arterial wall is almost denuded of endothelium. This loss of endothelium contributes to the smooth muscle cell (SMC) proliferation seen in restenosis, since the endothelium actively inhibits SMC hyperplasia. Over time, the endothelium recovers and SMC hyperplasia is arrested. The capacity of VEGF-coated stents to accelerate re-endothelialization, and to therefore reduce restenosis and thrombosis, was tested in this study. Radiolabeled VEGF was absorbed onto stents and released over nine days in an in vitro perfusion circuit. VEGF-coated stents were deployed in arterial segments to study local tissue release. A New Zealand White rabbit iliac artery model for stent implantation was used. Re-endothelialization and thrombosis were assessed after seven days. Further animals were examined 28 days post-procedure for in-stent restenosis. Stented vessels were resin-embedded, sectioned and stained. Intimal thickening was calculated using computerized morphometry. In vitro, the stents released 80% of the initial load over nine days. At seven days, thrombus was significantly reduced (12.5 mg for controls versus 0 mg for VEGF; p = 0.014). No beneficial effect was seen on endothelialization, nor on intimal hyperplasia. Neointimal area was 2.2 0.9 mm2 for controls versus 2.4 1.8 mm2 for VEGF (p = 0.8). These VEGF-eluting stents do not accelerate re-endothelialization or inhibit restenosis. Stent thrombosis appears to be reduced, which may make these stents less thrombogenic and be valuable in higher-risk cases.

Apoptotic index: use in predicting recurrence in breast cancer patients

Apoptosis maintains tissue homeostasis through its ability to control cell population and has been extensively studied in human cancers. Relation of apoptosis to prognosis is still controversial. In this study, we analyzed the prognostic significance of apoptotic and mitotic indices (AI & MI) using hematoxylin and eosin stained slides by light microscopy in breast cancer patients. In our study, apoptotic index was significantly associated with predicting relapse free survival (RFS), distant recurrence free survival (DRFS) and overall survival (OS) with lesions having higher apoptotic index showing poor prognosis. Our results also point out that quantitation of apoptotic index by simple light microscopy as a routine practice along with histological diagnosis, could provide additional prognostic information in patients who are at high risk of developing recurrence with breast cancers.

Topical application of beta-radiation to reduce intimal hyperplasia after carotid artery balloon injury in rabbit. A possible application for brachytherapy in vascular surgery

PURPOSE

Endovascular brachytherapy for the prevention of intimal hyperplasia (IH) and restenosis after balloon/stent angioplasty has proven effective both in animal preparations and clinical trials. A variety of beta-emitting isotopes and catheter-based devices have been developed for the delivery of low-dose radiation in clinical coronary and peripheral trials. No platform, however, has yet been developed for brachytherapy in concert with vascular surgical operations. The purpose of this study was to evaluate the vascular histopathologic response following balloon injury to rabbit carotid arteries with and without topically applied low-dose beta-radiation.

METHODS

The beta-emitting isotope strontium-90 (Sr-90) was conjugated onto the matrix of polypropylene (PLYP) mesh. Rabbit carotid arteries were balloon-injured with a #2 embolectomy catheter. Six carotid arteries were wrapped with nonradioactive PLYP mesh (controls) and Sr-90 ( approximately 90 microCi) PLYP mesh in order to deliver low-dose radiation to the vessel wall from the external (adventitial) surface. Tissue was harvested at 6 weeks and processed for histologic examination.

RESULTS

There was consistent blockade of fibrocellular neointima formation with virtually no neointima present in all treated segments, compared to moderate neointima formation in controls. Medial thinning and smooth muscle cell (SMC) necrosis were also associated with topical brachytherapy.

CONCLUSION

beta-Radiation applied by an externally wrapped PLYP mesh labeled with Sr-90 markedly suppressed neointima formation in an animal vascular surgical injury model. Further studies, however, are necessary to determine a suitable isotope and dosage for clinical application.

Effects of in vivo heregulin beta1 treatment in wild-type and ErbB gene-targeted mice depend on receptor levels and pregnancy

Mice heterozygous (+/-) for either heregulin (HRG), ErbB2, or ErbB3 were created by gene targeting, resulting in the loss of one functional gene copy and an associated decrease in targeted protein. We examined the in vivo activity of recombinant HRG peptide, rHRG beta1 (amino acids 177 to 241), in the three heterozygous mouse lines and in wild-type (WT) mice, both pregnant and nonpregnant. Nonpregnant WT and HRG(+/-) mice of both sexes were sensitive to rHRG beta1 treatment as evidenced by a high mortality rate associated with abdominal enlargement and parietal cell loss. However, pregnant WT mice and ErbB2 and ErbB3 heterozygous mice treated with rHRG beta1 were less affected, with significantly lower mortality rates and a less severe abdominal phenotype. Histological analysis revealed extensive breast ductal hyperplasia in females of all genotypes after rHRG beta1 treatment. Hyperplasia of other epithelial tissues such as the pancreas and intestine and the growth of cardiac nerve bundles were also observed, independent of sex.

The association between atypical adenomatous hyperplasia and primary lung cancer

Atypical adenomatous hyperplasia (AAH) has been suggested as the adenoma in an adenoma-carcinoma sequence in the lung periphery. From 1989-1998, we undertook a systematic, prospective search for AAH in lungs resected for cancer. AAH was found in 67 of 554 patients (12. 1%) with primary lung carcinoma (9.2% in male patients and 19.0% in females). AAH was found in lungs bearing adenocarcinoma (23.2%) more frequently than with large cell undifferentiated carcinoma (12.5%) or squamous carcinoma (3.3%). A greater percentage of females with adenocarcinoma had AAH (30.2%) than did males with adenocarcinoma (18.8%). Numbers of AAH ranged from 1-42 per patient and more patients had small numbers of AAH, although 12 patients had 6 or more AAH foci. Larger numbers of AAH tended to be found in adenocarcinoma-bearing lungs. Ten of the 67 patients with AAH and primary lung carcinoma (15%) had multiple primary cancers (range 2-6), all of which were adenocarcinoma. Synchronous cancers were rare in lung tumour-bearing resections without AAH. Patients with AAH show no difference in post-operative survival to those without, for all stages of carcinoma and for Stage I disease alone. This study provides evidence for a strong association between atypical adenomatous hyperplasia and primary lung adenocarcinoma and lends weight to the AAH/adenoma-carcinoma hypothesis.

Coexpression of IL-6 and soluble IL-6R causes nodular regenerative hyperplasia and adenomas of the liver

Studies with tumor necrosis factor p55 receptor- and interleukin-6 (IL-6)-deficient mice have shown that IL-6 is required for hepatocyte proliferation and reconstitution of the liver mass after partial hepatectomy. The biological activities of IL-6 are potentiated when this cytokine binds soluble forms of its specific receptor subunit (sIL-6R) and the resulting complex interacts with the transmembrane signaling chain gp130. We show here that double transgenic mice expressing high levels of both human IL-6 and sIL-6R under the control of liver-specific promoters spontaneously develop nodules of hepatocellular hyperplasia around periportal spaces and present signs of sustained hepatocyte proliferation. The resulting picture is identical to that of human nodular regenerative hyperplasia, a condition frequently associated with immunological and myeloproliferative disorders. In high expressors, hyperplastic lesions progress with time into discrete liver adenomas. These data strongly suggest that the IL-6/sIL-6R complex is both a primary stimulus to hepatocyte proliferation and a pathogenic factor of hepatocellular transformation.

Intraductal neoplasms of the pancreas

BACKGROUND

Since 1980 a group of pancreatic tumors have been termed intraductal papillary mucinous tumors (IPMT). Because these tumors occupy an intraductal position they are demonstrated by pancreatography to reside in the main pancreatic duct (MPD) or side branch ducts (SBD). Lesions of IPMT result in abdominal pain or pancreatitis symptoms because mucin production or papillary growth results in ductal obstruction. Only 104 cases had been reported in the literature by 1996 but more are being presented in abstract form. We reviewed our own 33 cases to assist defining operative decision-making criteria.

METHODS

All cases of IPMT between 1989 and 1997 were reviewed for clinical presentation, anatomy by endoscopic retrograde cholangiopancreatography and computed tomography, histologic findings, and long-term outcomes.

RESULTS

Our cases were older (65 years) and presented with disease centered mainly in the head of the gland. Clinical presentation was epigastric pain (82%), pancreatitis (56%), weight loss (36%), diabetes (27%), and jaundice (9%). Operations were pancreatectomy in 31 (Whipple n = 15, total n = 5, distal n = 10, local n = 1), bypass only (n = 1), and no operation (n = 1). Malignancy was found in 14 of 33 (42%). Factors significantly associated (P <0.05 Fisher exact test) with malignancy were history of alcohol abuse or death from disease. Jaundice or presence in both MPD and SBD approached a significant association with malignancy but not abdominal pain, weight loss, diabetes, preoperative serum elevations of amylase, SGOT, CA-19-9, or CEA; diffuse MPD dilation, gland region, gross mucus in ducts or filling defects, cytology, calcifications, or a pancreatic mass. In 31 resected patients after a follow-up of 37 months (1 to 103) death had occurred in 6 of 13 malignant cases and 0 of 18 with benign disease. Three-year actuarial survival was 82% (all) and 56% (malignant). Symptom recurrence after resection was found in 6 of 31 at a mean of 13 months postoperatively and was associated with death from disease (P <0.05) or presence of pain preoperatively.

CONCLUSION

Malignancy is common with IPMT and is more likely to be present with the clinical history of alcohol abuse or jaundice and if the tumor involves both the MPD and the SBD. The prognosis after resection is better than pancreatic cancer but the 19% recurrence of symptoms was equally seen with benign or malignant cases owing to residual disease in pancreatic remnants. The amount of resection should be extensive in patients likely to have malignancy (alcohol, jaundice, MPD+SBD). In those likely to redevelop symptoms, ie, those with preoperative pain, a careful assessment should be made via imaging studies for extent of disease.

The prognosis of resected lung carcinoma associated with atypical adenomatous hyperplasia: a comparison of the prognosis of well-differentiated adenocarcinoma associated with atypical adenomatous hyperplasia and intrapulmonary metastasis

BACKGROUND

Radiologically undetected intrapulmonary solitary nodules are sometimes found in the resected lung. When the main tumor is a well-differentiated (w/d) adenocarcinoma, especially a bronchioloalveolar carcinoma (BAC), it can be difficult to determine morphologically whether the intrapulmonary nodules are atypical adenomatous hyperplasia (AAH) or intrapulmonary metastasis (PM). The authors evaluated the accuracy of the differential diagnosis of these two lesions from the prognostic point of view.

METHODS

A retrospective study was conducted of 1360 lung carcinoma patients who had undergone surgical resection. Differential diagnosis was made between AAH and PM based on the conventional histologic specimens. Their clinicopathologic features were also studied. Survival rates were compared between these two groups.

RESULTS

AAH was found in 137 patients (10%) with resected lung carcinoma. The 5-year survival rates were 72.9% in Stage I, 60.6% in Stage II, 27.1% in Stage IIIA, 0% in Stage IIIB, and 0% in Stage IV. They were not significantly different from the figures for all patients in the corresponding pathologic stages. Seventy-six cases were diagnosed as w/d adenocarcinoma associated with AAH, whereas PM was found in 46 cases of w/d adenocarcinoma. The 5-year survival rates of AAH and PM differed significantly: 64.6% and 35.5%, respectively (P 0.0004). When a comparison was made between cases of pT1-2, N0 w/d adenocarcinoma, most of which were BAC, with PM (n = 22) and those with AAH (n = 52), the latter had significantly better survival (P = 0.0086).

CONCLUSIONS

The prognosis of resected lung carcinoma was not affected by association with AAH. The significant difference in prognosis between AAH and PM in w/d adenocarcinoma, especially in BAC, indicates that their morphologic distinction was correctly made by conventional pathologic examination in most cases.

Uremic small-artery disease with medial calcification and intimal hyperplasia (so-called calciphylaxis): a complication of chronic renal failure and benefit from parathyroidectomy

BACKGROUND

Uremic small-artery disease with medial calcification and intimal hyperplasia can lead to life-threatening skin necrosis or acral gangrene. It is a distinct complication of chronic renal failure that must be differentiated from soft-tissue calcification. An increased calcium-phosphate product and secondary hyperparathyroidism are the main underlying conditions. The benefit of parathyroidectomy is controversial.

OBJECTIVE

This article is based on a literature search to determine prognostic factors and, in particular, the benefit of parathyroidectomy.

METHODS

The literature on uremic small-artery disease (so-called calciphylaxis) was reviewed (full data set: 104 cases, including five of our own). The therapeutic benefit of parathyroidectomy and the relation between prognostic predictors (localization, dialysis, and transplant) and outcome were analyzed. The relation between diabetes and acral gangrene was also examined. Further epidemiologic data on the reviewed group of patients were established.

RESULTS

Thirty-eight of 58 patients who underwent parathyroidectomy survived compared with 13 of 37 patients who did not undergo parathyroidectomy (p = 0.007, n = 95). Forty of 53 patients with distal localization of necrosis survived compared with 11 of 42 patients with proximal pattern (p < 0.00001; n = 95). Dialysis and kidney transplantation followed by immunosuppression showed no relation to disease outcome. No association was found between diabetes and acral gangrene (p = 0.50).

CONCLUSION

Uremic small-artery disease is a distinct complication of chronic renal failure. Its recognition and early diagnosis should allow more effective treatment. In our retrospective study parathyroidectomy was significantly related to survival. Only a randomized, controlled, prospective trial (parathyroidectomy vs conservative treatment of secondary hyperparathyroidism) can establish the value of parathyroidectomy in uremic small-artery disease.

Benign liver tumors in children: a 25-year experience

The most common benign liver tumors are hemangiomas and hamartomas, both of mesenchymal origin. Mortality for patients with these tumors has traditionally been substantial despite benign histology. Between 1965 and 1989, 22 patients were treated for a benign liver tumor. This represents 42% of all primary neoplasms of the liver observed during this period. Incidental findings of liver tumors at autopsy were excluded from this series. There were 9 boys and 13 girls with a mean age at presentation of 2.3 years (range, birth to 14 years). Sixteen had hemangiomas and presented earlier in life (mean age, 4.4 months). In this subgroup, high-output cardiac failure was present in 58% of the newborns. Seven hemangiomas were resected, four were observed, three were treated with digitalis, diuretics, and steroids, and one received epsilon-aminocaproic acid. Nonhemangiomatous tumors included four hamartomas, one focal nodular hyperplasia, and one nodular transformation. All six were resected. There was one death early in the series. At a mean follow-up of 38 months, 21 of the 22 patients are cured or asymptomatic. In the past, mortality rates of close to 90% have prompted many investigators to advocate resection of every symptomatic hemangioma. With the availability of more sophisticated imaging techniques and refinements in the treatment of cardiac failure, surgery can be used more selectively. Hepatic resections, once considered heroic, can now be performed with minimal morbidity and virtually no mortality. The 96% survival in this series of benign liver tumors contrasts with high mortality rates reported in the literature and illustrates the spectacular improvements that have been made in the diagnosis and management of these once ill-reputed tumors.

Behaviour of dendritic reticulum cells possessing immunoreactive acid cysteine-proteinase inhibitor in human lymphoid secondary follicles and in follicular-centre cell lymphomas

In our previous studies acid cysteine-proteinase inhibitor (ACPI) was shown to be a common characteristic of human squamous epithelia and dendritic reticulum cells (DRC) in lymphoid secondary follicles. In the present study, the behaviour of ACPI-immunoreactive DRC in reactive lymphoid secondary follicles and neoplastic follicles of follicular-centre cell (FCC) lymphomas was compared by the peroxidase-antiperoxidase method. The secondary follicles in reactive lymphoid tissues revealed a staining pattern characteristic of DRC comparable with the results of other studies. Contrary to this, the number of ACPI-positive DRC in the neoplastic lymphoid follicles was greatly reduced. This was occasionally accompanied by a weak reaction and in many cases the DRC were totally abolished. Moreover, morphological aberrations were observed in ACPI-positive DRC, especially diminution and shortening of dendritic processes. On occasion, ACPI-positive cell types were observed, which may represent intermediate forms between DRC and fibroblastic reticulum cells. Only one case--with a rather favourable clinical outcome (out of 41 follicular FCC lymphomas) exhibited an ACPI-positive DRC pattern comparable with that of reactive lymphoid follicles. Thus it seems that the ACPI-immunohistochemistry of DRC provides an additional tool for discerning the difference between reactive and neoplastic lymphoid follicles. This method is of particular value since it can be used with formalin-fixed, paraffin-embedded tissues. There was a tendency among the follicular FCC lymphoma patients towards a better survival rate for those with ACPI-positive DRC than for those lacking this cell type, although no statistically significant differences emerged from this limited material.

Clinicopathologic characteristics of orbital lymphoid hyperplasia

The clinical characteristics and microscopic features of the biopsy specimens of 66 patients with orbital lymphoid tumors were analyzed with respect to clinical outcome (disease remaining localized to the orbit or developing associated extraorbital lesions). The patients' average age was 63 years, and their tumors had a marked tendency to arise in the anterosuperior orbit. No clinical or radiographic findings helped to distinguish the cases of localized disease from disseminated disease. The lesions were divided microscopically into three categories: reactive lymphoid hyperplasia (16), atypical lymphoid hyperplasia (38), and malignant lymphoma (12). Extraorbital lesions developed in 25%, 50%, and 75% of cases, respectively. The five-year mortality rates were also significantly different for each type of lesion: 6%, 19%, and 58%, respectively.