Evaluation of a preemptive strategy for BK polyomavirus-associated nephropathy based on prospective monitoring of BK viremia: a kidney transplantation center experience.

INTRODUCTION: BK polyomavirus-associated nephropathy (BKPVAN) is a major cause of renal failure early after kidney transplantation. The present study reports the preliminary results of prospective monitoring including a preemptive strategy for BKPVAN during the first year after kidney transplantation. METHODS: We monitored BK virus DNA in blood at months 1, 2, 3, 6, 9, and 12 among 92 subjects who received induction therapy (basiliximab or antithymocyte globulin), and maintenance immunosuppression with prednisone, mycophenolate mofetil, and tacrolimus. Patients with two or more consecutive measurements of viral load >10(4) copies/mL were treated with a stepwise approach including dose reduction or discontinuation of mycophenolate mofetil eventually followed by reduction of tacrolimus and introduction of leflunomide. RESULTS: Within 1 year, seven (7%) patients displayed sustained BK viremia at a median of 92 days after transplantation. Among 68 patients who underwent a renal allograft biopsy, seven were diagnosed as BKPVAN at a median of 15 weeks after transplantation. The diagnosis was achieved by a surveillance biopsy in four patients with stable renal function. BKPVAN was preceded by asymptomatic viremia except for two cases in whom BK viremia occurred at 6 or 11 months, after the histological diagnosis. At 12 months, six patients had cleared their viremia. Serum creatinine levels had stabilized in six recipients with BKPVAN estimated renal function was 43.7 ± 16.3 mL/min in patients with viremia and/or BKPVAN versus 61.3 ± 20.1 mL/min among patients who never became viremic (P = .03). None of the patients with viremia and/or BKPVAN lost the allograft. CONCLUSION: BKPVAN may occur early after kidney transplantation, at a low or undetectable viremia or at some weeks after the first positive viremia. Intensive monitoring during the first 4 months after transplantation together with early protocol biopsies or interventions prompted by BK viremia may optimize BKPVAN diagnosis at a subclinical stage, thus avoiding renal dysfunction.

Renal and vascular effects of chronic endothelin receptor antagonism in malignant hypertensive rats.

The effect of the combined ETA/ETB endothelin receptor antagonist bosentan on blood pressure, vascular hypertrophy, and pathologic renal changes was investigated in a model of malignant hypertension, severe vascular hypertrophy, and enhanced vascular expression of endothelin-1, the deoxycorticosterone acetate (DOCA), and salt-treated spontaneously hypertensive rat (SHR). DOCA-salt treated SHR received 100 mg bosentan per kilogram weight per day mixed with their food. Systolic blood pressure of untreated DOCA-salt SHR rose to 241 +/- 1.5 mm Hg, whereas that of bosentan-treated rats rose to 221 +/- 5.1 mm Hg (P < .01). Cardiac and conduit artery mass were not affected by treatment. Small arteries from the coronary, renal, and mesenteric circulations showed a smaller media width and cross-sectional area of the media in rats treated with bosentan than in untreated rats. The kidneys showed the presence of fibrinoid necrosis in a high percentage of afferent arterioles and glomeruli of untreated DOCA-SHR. Some kidneys of treated rats exhibited less severe vascular hypertrophy and lesser extent of vascular or glomerular fibrinoid necrosis, but the renal injury score of bosentan-treated DOCA-SHR was only at the limit of significance from that of untreated rats (P = .06). These results suggest a role for endothelin-1 in blood pressure elevation and the severe vascular hypertrophy of small arteries of the coronary, renal, and mesenteric vasculature, but not of the heart or larger conduit vessels in the malignant hypertension that SHR develop after treatment with DOCA and salt. Although some bosentan-treated rats showed fewer renal lesions, a significant effect on renal pathology could not be unambiguously demonstrated. Further studies will be necessary to determine whether endothelin antagonists may indeed offer some degree of renal protection and have therapeutic potential in severe or malignant hypertension.

Pleomorphic soft tissue myogenic sarcomas of adulthood. A reappraisal in the mid-1990s.

325 diverse sarcomas, 39 rhabdomyosarcomas (RMS), including all histologic variants, and 135 leiomyosarcomas (LMS) were identified. Within these two groups, 18 (46%) of the RMS and 14 (10%) of the LMS represented pleomorphic variants. These neoplasms were studied by morphology (histology and ultrastructure) and by immunohistochemical methods employing antibodies to intermediate filaments (vimentin and desmin) and actin isoforms [alpha-smooth (sm) and alpha-sarcomeric (sr) actins]. Twenty-four pleomorphic malignant fibrous histiocytomas (MFH) and eight pleomorphic liposarcomas (LS) were examined in a similar fashion. By light microscopy, the pleomorphic RMS, LMS, and MFH were indistinguishable, as each was dominated by pleomorphic cells disposed in a haphazard growth pattern; moreover, many featured fascicular, storiform, and sclerotic zones. The distinction between these neoplasms became apparent only following immunohistochemistry and/or ultrastructural study. All pleomorphic RMS disclosed rudimentary sarcomeres and exhibited the following cytoskeletal profile: vimentin (+) (18 of 18), desmin (+) (14 of 18), alpha-sr actin (+) (18 of 18) and alpha-sm actin (+) (five of 18). All the pleomorphic LMS featured smooth-muscle differentiation of variable degrees in the form of cytoplasmic bundles of microfilaments and associated dense bodies; their cytoskeletal profile was vimentin (+) (14 of 14), desmin (+) (seven of 14), alpha-sr actin (+) (none of 14), and alpha-sm actin (+) (eight of 14). The latter was demonstrated in all moderately differentiated, but absent or only focally expressed in poorly differentiated variants. All pleomorphic MFH and LS were devoid of myogenic (skeletal or smooth) ultrastructural features and expressed vimentin solely. This combined morphological and immunohistochemical study illustrates the following: First, these pleomorphic sarcomas are often indistinguishable by histologic growth pattern alone; thus, an accurate diagnosis requires study with all of these techniques. Second, pleomorphic myogenic sarcomas are restricted to adults and are not uncommon neoplasms among pleomorphic sarcomas: RMS (28%), LMS (21%), MFH (38%), and LS (13%). Third, the study defines desmin-negative and alpha-sm actin-positive pleomorphic RMS, and desmin-negative and alpha-sm-actin-negative pleomorphic LMS.

Familial hemolytic-uremic syndrome and homozygous factor H deficiency.

Inherited hemolytic-uremic syndrome (HUS) is unusual. We report the occurrence of HUS in two siblings; one died at an early age while the other (the proband) has presented with three episodes of HUS since the age of 19 years. The finding of a persistently low serum C3 level in this patient led to a thorough evaluation of her complement cascade and a family investigation. The proband and her asymptomatic younger sister were found to have very low serum levels (5% of normal) of factor H, a regulatory protein of the alternative complement pathway. Both patients had low levels of serum C3, factor B, CH50 and VAH50, reflecting persistent alternative pathway activation. The father and mother both had half-normal serum factor H levels but an otherwise normal complement profile. Other members of the extended pedigree were also found to have half-normal serum factor H levels. In conclusion, in this family, factor H deficiency appears to be associated with HUS and is transmitted as an autosomal recessive trait. Persistent C3 hypocomplementemia in the setting of familial and/or recurrent HUS should be a clue to a possible inherited complement deficiency.

Malignant fibrous histiocytoma in a patient with Blackfan-Diamond anemia.

Blackfan-Diamond anemia, a chronic, pure red cell aplasia, is rare. Malignant fibrous histiocytoma is also uncommon; it can arise in pre-existing bone lesions. The authors describe a 23-year-old man with Blackfan-Diamond anemia complicated by hemochromatosis in whom malignant fibrous histiocytoma developed in the distal femur.

All histological types of primary human rhabdomyosarcoma express alpha-cardiac and not alpha-skeletal actin messenger RNA.

Eleven human primary rhabdomyosarcomas (RMSs), including all histological variants, were analyzed morphologically, immunohistochemically for intermediate filament proteins and actin isoforms, and by means of Northern blots with probes specific for total actin, alpha-skeletal (SK), alpha-cardiac (CARD), and alpha-smooth muscle actin messenger (m)RNAs. All tumors disclosed ultrastructural evidence of skeletal muscle features with terminal differentiation in three cases. The RMSs contained immunohistochemically the intermediate filament proteins vimentin and desmin and reacted positively with the alpha-sarcomeric actin antibody, which recognizes alpha-SK and alpha-CARD actin isoforms. All RMSs reacted with the total actin probe, recognizing at 2.1 kb cytoplasmic actin mRNAs and at 1.7 kb alpha-actin mRNAs. With the specific probes, all RMSs expressed alpha-CARD actin mRNA, four neoplasms expressed also alpha-smooth muscle actin mRNA, whereas the probe for alpha-SK actin mRNA never produced a signal except in one case, in which the tumor masses were intermingled with non-neoplastic preexistent striated muscle fibers. Because alpha-CARD and alpha-smooth muscle actins are transiently expressed during normal skeletal muscle development, RMSs seem to follow normal skeletal myogenesis without completing the final step, consisting of alpha-SK actin mRNA expression. The use of Northern blots for alpha-CARD actin as an adjunct to conventional techniques may be helpful for the precise identification of primary RMSs compared to other soft tissue neoplasms.

Glycogen-rich clear cell rhabdomyosarcoma of the mediastinum. Potential diagnostic pitfall.

A 63-year-old black man of Caribbean origin, seropositive for human T-cell lymphoma virus type I (HTLV-I), presented with a 4-week history of progressive dyspnea, and was found to have a tumor of the anterior mediastinum. Incisional biopsy revealed a malignant neoplasm with a solid pattern of glycogen-rich clear cells. Diffuse expression of vimentin was observed, whereas only rare cells were immunoreactive for muscle-specific actin and desmin. Ultrastructure revealed a large amount of mono-particulate glycogen in most cells and features of rhabdomyogenic differentiation in occasional cells. The autopsy revealed a 23 x 14-cm (1,345 g), soft and white mediastinal neoplasm bulging in the right thorax with right pleural metastases. HTLV-1 proviral genome was not detected within tumor cells by polymerase chain reaction. This rhabdomyosarcoma is best classified as the solid subtype of the alveolar variant, with an unusually large amount of cytoplasmic glycogen. Clear cell rhabdomyosarcoma could be potentially confused with more commonly encountered clear cell tumors, particularly in the mediastinum.

Ciclosporin in Goodpasture's syndrome.

We report the case of a 39-year-old male patient with Goodpasture's syndrome. Despite therapy with prednisone, cyclophosphamide and plasma exchanges, serum creatinine (Scr) progressively increased up to 10.3 mg/dl (936 mumol/l) and hemoptysis recurred 3 months after initiation of treatment. Ciclosporin (CS) starting at 6 mg/kg/day was given. Scr began to decrease 2 weeks later and eventually stabilized at approximately 2.0 mg% (182 mumol/l). This case illustrates one of the potential uses of CS in human glomerular disease.

Coexpression of alpha-sarcomeric actin, alpha-smooth muscle actin and desmin during myogenesis in rat and mouse embryos I. Skeletal muscle.

Expression of vimentin, desmin, alpha-sarcomeric and alpha-smooth muscle actins in embryonic tissues of rat and mice was examined using an immunohistochemical approach. The results showed a similarity in the expression of desmin and alpha-actin isoforms (alpha-sr and alpha-sm) in skeletal muscle cells during murine feto-embryonic development. In the two species, coexpression of alpha-sr and alpha-sm actins has been observed in cardiomyoblasts, myotomal myoblasts and myotubes. The intensity of alpha-sm actin expression decreased during the terminal steps of myogenesis and disappeared completely in mature cardiomyocytes and myofibres. Desmin was expressed in all prefusion myoblasts (type 1 and 2 myoblasts), myotubes, and in myofibres. The appearance of desmin in myoblasts of somites preceded by a few hours the expression of the alpha-actins (alpha-sr and alpha-sm). Our study on vimentin expression, limited to rat embryos, revealed that somite premyoblasts expressed only vimentin, type 1 myoblasts expressed vimentin and desmin, and type 2 myoblasts (rhabdomyoblasts) expressed desmin and alpha-actins (alpha-sr and alpha-sm). Our study demonstrates the resemblance between feto-embryonic myogenesis and myogenic neoplastic differentiation: desmin appears before the alpha-actins in embryonic myoblasts, and can be considered as a marker of an initial step in myogenic differentiation. alpha-sm actin, considered as a striated muscle cell feto-embryonic actin, is expressed transiently in skeletal myoblasts and cardiomyoblasts during development and reappears during neoplastic transformation of skeletal muscle.

Intermediate filament proteins and actin isoforms as markers for soft-tissue tumor differentiation and origin. III. Hemangiopericytomas and glomus tumors.

Intermediate filament proteins and actin isoforms of a series of 12 malignant hemangiopericytomas and five glomus tumors were examined by light microscopy, transmission electron microscopy, two-dimensional gel electrophoresis (2D-GE), and by immunohistochemistry, the latter using monoclonal or affinity-purified polyclonal antibodies to desmin, vimentin, cytokeratins, alpha-smooth muscle, and alpha-sarcomeric actins. By light microscopy, all hemangiopericytomas disclosed a predominant vascular pattern with scant storiform, myxoid and spindle cell areas, and with variable degrees of perivascular fibrosis. By ultrastructure, smooth muscle differentiation was observed in each hemangiopericytoma. Immunohistochemically, neoplastic cells of hemangiopericytomas expressed vimentin as the sole intermediate filament protein and lacked alpha-smooth muscle or alpha-sarcomeric actins. 2D-GE revealed only beta and gamma actins, in proportions typical for fibroblastic tissues. Glomus tumors revealed vimentin and alpha-smooth muscle actin within glomus cells by immunohistochemical techniques and disclosed ultrastructurally distinct smooth muscle differentiation. Therefore hemangiopericytomas represent a distinct soft-tissue neoplasm with uniform morphologic, immunohistochemical, and biochemical features most likely related to glomus tumors, the former representing an aggressive and potentially malignant neoplasm of vascular smooth muscle cells and the latter a well-differentiated neoplasm of vascular smooth muscle cells. Because malignant hemangiopericytomas disclose smooth muscle differentiation by ultrastructure, but do not express alpha-smooth muscle actin, as normal pericytes and glomus cells, it is suggested that these neoplasms represent highly vascularized smooth muscle neoplasms, ie, poorly differentiated leiomyosarcomas derived from vascular smooth muscle cells or their equivalent, the pericytes, which have lost alpha-smooth muscle actin as a differentiation marker that is similar to many conventional poorly differentiated leiomyosarcomas.

Myofibroblasts from diverse pathologic settings are heterogeneous in their content of actin isoforms and intermediate filament proteins.

We examined by immunofluorescence the distribution of vimentin, desmin, alpha-smooth muscle actin and alpha-sarcomeric actin in normal human soft tissues and in pathologic tissues containing myofibroblasts, including normally healing granulation tissue, hypertrophic scar, and fibromatosis. The pattern of actin isoforms was also documented biochemically by two-dimensional gel electrophoresis. Fibroblastic and/or myofibroblastic cells in each setting always expressed vimentin and never alpha-sarcomeric actin. Moreover, these cells showed an heterogeneous cytoskeletal composition which defined four phenotypes: (a) cells expressing only vimentin; (b) cells expressing vimentin, alpha-smooth muscle actin and desmin; (c) cells expressing vimentin and alpha-smooth muscle actin; and (d) cells expressing vimentin and desmin. Given this, two groups of lesions are distinguished: the first contains only vimentin cells and consists of normally healing granulation tissue, eschars and normally healed scars; the second contains vimentin cells admixed with variable proportions of vimentin, alpha-smooth muscle actin and desmin, vimentin and alpha-smooth muscle actin, and vimentin and desmin cells and consists of hypertrophic scars and fibromatoses. Immunogold electron microscopy showed that alpha-smooth muscle actin was present in a proportion of cells with ultrastructural features of myofibroblasts. Our findings suggest that contrary to myofibroblasts of normally healing granulation tissue and normally healed scars, myofibroblasts of pathologic conditions characterized by chronic retraction express always immunochemical features indicative of smooth muscle differentiation.

Medullary thyroid carcinoma: localization of a mediastinal metastasis with I-131 MIBG.

An I-131 metaiodobenzylguanidine (MIBG) scan was performed in a patient with a familial history of multiple endocrine neoplasia (MEN) type 2 and recurrent medullary thyroid carcinoma (MTC). The scan revealed a mediastinal metastasis from her MTC and there was also an imaging pattern of bilateral adreno-medullary hyperplasia. Although the literature indicates that I-131-MIBG scanning is not sufficiently sensitive for the detection of MTC, this procedure has proven to be of value in the management of chosen patients with MEN-associated MTC.

Identification and localization of 7B2 protein in human, porcine, and rat thyroid gland and in human medullary carcinoma.

The novel, highly conserved polypeptide 7B2, which belongs to a new protein superfamily, was isolated from human and porcine hypophysis. The availability of a specific antibody to a synthetic fragment enabled 7B2 localization in a number of neurocrine and endocrine tissues and revealed its secretory character. 7B2 was purified from thyroid homogenates by HPLC chromatography and characterized by gel permeation chromatography (dimeric mol wt, approximately 40,000) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (monomeric mol wt, 20,750). By immunocytochemistry 7B2 was colocalized with calcitonin in parafollicular cells and identified within secretory granules by electron microscopy. Three of nineteen human medullary carcinoma cases showed immunoreactive 7B2 within the early and late hyperplasia stages and neoplasia. Results suggest that 7B2 may play a role in endocrine function, possibly as a secretory substance, and may be a histochemical marker in addition to calcitonin for medullary carcinoma.

Smooth-muscle differentiation in stromal cells of malignant and non-malignant breast tissues.

A mouse monoclonal antibody (MAb) recognizing alpha-smooth-muscle actin has been used to study smooth-muscle differentiation features in the stromal cells of desmoplastic reactions accompanying mammary tumors. We have studied, by the same immunohistochemical technique, a series of malignant and non-malignant human breast tissues. Cells composing the desmoplastic reaction were found to express alpha-smooth-muscle actin in all the 11 breast carcinomas examined, whereas no immunostain was demonstrated in the stromal cells of 7 breast tissue samples histologically defined as normal. Three of 9 cases of fibrocystic disease showed a minority of positively stained stromal cells, generally in association with epithelial hyperplasia. All the 7 cases of sclerosing adenosis, 3 of 4 cases of diffuse papillomatosis and all 3 intraductal papillomas exhibited a majority of immunoreactive stromal cells. Numerous stromal cells in 3 of 11 circumscribed fibroadenomas analyzed expressed low amounts of alpha-smooth-muscle actin. The factor(s) responsible for smooth-muscle differentiation in stromal cells are presently unknown, but the detection of this previously unsuspected stromal cell phenotype in nonmalignant mammary tissues might help in characterizing the variant morphological aspects designated under the label "fibrocystic disease" and in understanding the biology of premalignant or early malignant lesions of the breast.

Intermediate filament proteins and actin isoforms as markers for soft tissue tumor differentiation and origin. II. Rhabdomyosarcomas.

A series of 15 rhabdomyosarcomas was examined by light microscopy, transmission electron microscopy, two-dimensional gel electrophoresis (2D-GE) and indirect immunofluorescence, the latter using monoclonal or affinity-purified polyclonal antibodies to desmin, vimentin, alpha-smooth muscle and alpha-sarcomeric (alpha-sr) actins. By light microscopy, the authors diagnosed 1 botrioid, 1 alveolar, and 7 embryonal rhabdomyosarcomas, 4 pleomorphic spindle cell sarcomas, and 2 spindle cell sarcomas, one nondistinct, the other with a hemangiopericytomatous pattern. By transmission electron microscopy, 13 neoplasms disclosed rhabdomyoblastic differentiation; the remaining 2, myogenic differentiation. By immunofluorescence microscopy, all neoplasms expressed vimentin and alpha-sr actin, 12 expressed, in addition, desmin, and 1 expressed alpha-smooth muscle actin. Among the 11 neoplasms studied by means of 2D-GE, 7 demonstrated an alpha-actin spot, while 4 showed only beta and gamma spots. One tumor disclosed, in addition to alpha, beta, and gamma spots, a spot with a molecular weight corresponding to actin, but more acidic than alpha-actins. This study demonstrates that alpha-sr actin antibody represents a valuable marker for the diagnosis of rhabdomyosarcoma, because it was present in all neoplasms, including the one negative for desmin. This antibody further allowed the recognition of pleomorphic variants and morphologically atypical forms of rhabdomyosarcomas. The presence of alpha-smooth muscle actin in 1 case of rhabdomyosarcoma suggests that this actin isoform may be expressed during skeletal muscle differentiation.