Differential nephrotoxicity of low molecular weight proteins including Bence Jones proteins in the perfused rat nephron in vivo.

To investigate the pathogenetic mechanisms of tubule nephrotoxicity of low molecular weight proteins (LMWP), proximal tubules (PT) of rats were perfused in vivo with artificial tubule fluid (ATF) containing one of five LMWPs: three human Bence Jones proteins (BJP), beta-lactoglobulin (BLG), and rabbit myoglobin (MYG). Volume (JV), chloride (JCl) and glucose (JG) fluxes in these perfused PTs were compared with those determined using ATF alone. In separate experiments, perfused nephrons were examined with electron and immunoelectron microscopy. After exposure to BJP1 or BLG, JV, JCl, and JG were less (P less than 0.05) than corresponding control fluxes. Cell damage of these perfused PTs, along with cellular debris in the distal tubules, was prominent. The PT lysosomes often appeared atypical and contained crystals. In contrast, perfusion with BJP2, BJP3, or MYG did not alter JV, JCl, or JG. These findings were corroborated by the normal ultrastructure of these PTs despite immunohistochemical evidence of endocytosis of the BJPs. Isoelectric point, molecular form, and isotype were not factors associated with PT damage. In addition, proteins with pI less than 7.4 precipitated in the distal nephron, forming acellular casts. Thus, certain nephrotoxic LMWPs damaged the PT, while others precipitated in the distal tubule, obstructing the nephron. These two pathogenetic mechanisms may independently be responsible for tubulointerstitial nephropathy of LMWPs in humans.

Adulticidal and oviposition- and hatching-altering activities of essential oil from Mexican oregano leaves (Lippia graveolens H.B.K.) against the cattle tick Rhipicephalus microplus (Acari: Ixodidae).

Adulticidal and oviposition- and hatching-altering activities of essential oil extracted from Mexican oregano leaves (Lippia graveolens H.B.K.) (OEO) were evaluated on engorged adult female Rhipicephalus microplus ticks using the adult immersion test bioassay. Twofold dilutions of OEO were tested from a starting dilution of 10% down to 1.25%. Results showed 100% adulticidal activity at 10% OEO concentration and oviposition inhibition of 65.8% and 40.9% at 5.0% and 2.5% OEO concentration, respectively. Egg hatching inhibition was achieved by 26.0% and 11.5% at 5.0% and 2.5% OEO concentration, respectively. These effects could be attributed to OEO major components: thymol, carvacrol and p-cymene, which together account for more than 60.0% of the OEO chemical composition. Mexican oregano could represent a potential source for development of alternative tick control agents.

Increased hyaluronic acid in the inner renal medulla of obese dogs.

Dogs placed on a high-fat diet develop obesity and hypertension associated with marked sodium retention that is due to increased tubular reabsorption. Previous studies showed that renal interstitial hydrostatic pressure is elevated in obese dogs compared with lean dogs, and histological studies revealed increases in medullary interstitial cells and expansion of the medullary but not the cortical extracellular matrix. This matrix stained intensively with Alcian Blue at pH 2.6, colloidal iron, and periodic acid-Schiff, suggesting increased glycosaminoglycans. The goal of this study was to quantitate medullary glycosaminoglycan content in obese (n = 8) compared with lean (n = 8) dogs. Measurement of total glycosaminoglycan content, estimated from uronic acid content, and of hyaluronate, the most abundant glycosaminoglycan in canine renal medulla, with an enzyme-linked immunosorbent assay indicated that there were no significant differences in total glycosaminoglycan or hyaluronate contents in the outer medulla of obese dogs compared with those in lean dogs. In contrast, in the inner medulla of obese dogs there was a 140% increase in hyaluronate compared with the content in lean dogs (4.3 +/- 0.5 versus 1.8 +/- 0.2 mg hyaluronate per gram wet tissue, respectively; P < .05); however, total glycosaminoglycan content was not significantly different (6.9 +/- 0.7 versus 6.2 +/- 0.5 mg uronic acid per gram wet tissue) in obese and lean dogs. These results suggest a change in the relative proportion of the glycosaminoglycan species in the inner medulla of obese dogs, with a selective increase in hyaluronate.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute cryoglobulinemic renal failure after intravenous infusion of gamma globulin.

A 39-year-old woman had mixed IgM/IgG cryoglobulinemia, but was later found to have a lymphoma that produced an IgM kappa paraprotein with rheumatoid factor activity. With intermittent chlorambucil and prednisone therapy, the lymphoma was controlled for five years and she had no evidence of cryoglobulinemia. Because of the presence of intractable pulmonary infection and hypogammaglobulinemia G, she was given an intravenous infusion of gamma globulin. Within 72 hours, renal failure and a sustained decrease in serum concentrations of IgM and IgG began concurrently. A kidney biopsy specimen obtained five days after the infusion showed hyaline "thrombi" in numerous glomerular capillaries and glomerular necrosis, consistent with acute, severe mixed cryoglobulinemic nephropathy. Immunostaining showed strong positivity for IgM, IgG, and light chains in glomerular capillary lumina and subendothelial sites; immunostaining with a monoclonal antiidiotypic antibody specific for the patient's paraprotein established the presence of the rheumatoid factor paraprotein in the deposits. These observations strongly suggest that complexes consisting of IgM kappa rheumatoid factor, IgG, and complement initiated the renal damage. Therefore, demonstrable serum rheumatoid factor activity in patients with B cell neoplasms should be considered a contraindication to the administration of intravenous gamma globulin.

Histologic variation in the skin lesions of the glucagonoma syndrome.

Three cases of glucagonoma syndrome were seen in 1 year. Study of the skin biopsies from the first two cases led to a correct diagnosis from skin biopsy of the third case, although it was not suggested clinically. In each case serum glucagon levels were high and a pancreatic tumor was found, with complete remission of symptoms in cases 1 and 3 after resection; case 2 refused surgery and has died. A total of nine skin biopsies from the three patients showed a variety of findings: epidermal necrosis; subcorneal pustules, either isolated or associated with necrosis of the epidermis; confluent parakeratosis, epidermal hyperplasia, and marked papillary dermal angioplasia; and suppurative folliculitis. The clinical lesions in this syndrome vary from bright red macules to annular superficial erosions and flaccid pustules. Similarly, several histopathologic features of the disease can occur, which may represent the progression of the disease. No single histologic feature was specific for the disease, but a combination of the features is probably diagnostic. Therefore, multiple skin biopsies are recommended when this diagnosis is suspected.

Immunolocalization of FGF-1 and receptors in human renal allograft vasculopathy associated with chronic rejection.

Despite recognition of chronic vasculo-occlusive disease in solid organ transplantation, the exact pathophysiologic events resulting in neointima formation remain to be elucidated. Since acidic fibroblast growth factor (FGF-1) is an established modulator of vascular cell function, we examined the expression of this growth factor and its high affinity receptors in both relevant renal transplant controls (n = 5) and tissue from patients (n = 19) who underwent nephrectomy following graft loss secondary to chronic rejection. In situ hybridization and immunohistochemical studies demonstrated minimal vascular expression and distribution of FGF-1 and FGF high affinity receptors in the normal human kidney. In contrast, vascular lesions in kidney allografts experiencing chronic rejection demonstrated the exaggerated appearance of FGF-1 ligand and receptors. Immunoreactive FGF-1 readily was detected in medial smooth muscle cells and focal areas of intimal hyperplasia, particularly in association with the presence of inflammatory infiltrate. Enhanced staining for FGF-1 mRNA primarily was associated with the appearance of resident inflammatory cells. Medial smooth muscle cells of hyperplastic vascular structures demonstrated the greatest immunoappearance of FGF receptors-however, diffuse immunostaining also was observed in areas of intimal hyperplasia. The enhanced appearance of both FGF-1 and FGF receptors in the vascular wall suggests that this polypeptide mitogen may serve as an important mediator of growth responses associated with neointima development and angiogenesis during chronic rejection of human renal allografts.

Immunolocalization of FGF-1 and receptors in glomerular lesions associated with chronic human renal allograft rejection.

Glomerular lesions are considered one of the more detrimental pathologic changes associated with chronic rejection of renal allografts. To elucidate potential pathophysiologic mechanisms associated with transplant glomerulopathy, we examined the expression of acidic fibroblast growth factor (FGF-1) and its high-affinity receptors (FGFR) in both relevant renal transplant controls (n=5) and tissue from patients (n=19) who underwent nephrectomy following graft loss secondary to chronic rejection. In situ immunohistochemical analyses demonstrated minimal staining and distribution of FGFR and FGF-1, which was localized to the mesangial matrix in glomeruli from normal human kidneys. In situ hybridization failed to detect the presence of FGF-1 mRNA in control tissue. In contrast, each stage of the developing glomerular lesion associated with chronic rejection demonstrated the exaggerated appearance of FGF-1 protein in visceral and parietal epithelial cells. Intense staining for FGF-1 protein did not correlate with the increased appearance of FGF-1 mRNA, which was restricted to circulating inflammatory cells. Glomeruli in kidneys with findings of chronic rejection also exhibited increased immunodetection of both FGFR and PCNA in mesangial and epithelial cells. Immunogold labeling of chronically rejected visceral epithelial cells revealed both cytoplasmic and nuclear/localization of FGF-1, thereby establishing mitogenic potential of the growth factor. The enhanced appearance of both biologically active FGF-1 and FGFR suggests that this polypeptide may serve as an important mediator of growth responses associated with glomerular lesion development during chronic rejection.

Immunolocalization of acidic fibroblast growth factor and receptors in the tubulointerstitial compartment of chronically rejected human renal allografts.

Tubular damage and loss associated with interstitial inflammation and fibrosis may be the most important determinants in chronic renal allograft rejection. To elucidate potential pathophysiologic mechanisms associated with tubulointerstitial lesions, we examined the expression of a fibrogenic cytokine, acidic fibroblast growth factor (FGF-1) and its high-affinity receptors, in both relevant renal transplant controls (n=5) and tissue from patients (n=19) who underwent nephrectomy after graft loss, secondary to chronic rejection. In situ hybridization and immunohistochemical analyses demonstrated minimal expression of FGF-1 mRNA and protein in the tubulointerstitial compartment of the normal human kidney. In contrast, tubulointerstitial lesions in kidney allografts experiencing chronic rejection demonstrated the exaggerated appearance of both FGF-1 protein and mRNA in resident inflammatory and tubular epithelial cells. Patterns of staining were consistent throughout tubular compartments and did not appear to be localized to any particular region. The tubulointerstitium in kidneys with findings of chronic rejection also exhibited increased immunodetection of proliferating cell nuclear antigen in the tubular epithelium, inflammatory cell infiltrate, and neovascular structures. The enhanced appearance of FGF-1 and readily detectable fibroblast growth factor receptors suggests that this polypeptide mitogen may serve as an important mediator of growth and repair responses, associated with development of angiogenesis and tubulointerstitial lesions during chronic rejection of human renal allografts.

Monoclonal immunoglobulin light chain-related renal diseases.

The spectrum of renal lesions associated with deposition of monoclonal light chains is varied and extensive, yet the simultaneous occurrence of two or more of these lesions in the same patient is unusually recognized. In addition, patients may excrete large amounts of monoclonal light chains and have no clinically evident renal dysfunction. Thus, the type of renal lesion that occurs appears to depend on the physiochemical properties of the unique monoclonal light chain produced. The particular nephrotoxic properties responsible have not yet been identified but are currently under intensive examination. For example, various studies suggest that cast-forming Bence Jones proteins have isoelectric points above 5.1. Finally, along with these intrinsic properties, environmental factors combine to promulgate the lesion or prevent clinical expression of renal injury. Attention to the subtle morphological renal manifestations of MLCRRD is essential to diagnose these diseases early in the course. Characterization of the morphological pattern and degree of renal affectation is important because therapeutic modalities may vary accordingly. As understanding of the molecular events responsible for the renal alterations improves, additional therapeutic approaches may emerge to reverse renal failure in MLCRRD.

Neurosecretory granule-like structures in lymphomas.

This report concerns the finding of round to ovoid electron dense, membrane bound structures 100 to 300 nm. in average diameter in four non-Hodgkin lymphoma cases studied ultrastructurally. In three of the cases the material for electron microscopy was obtained from lymph nodes. Two of the lymph nodes were replaced by nodular, poorly to moderately differentiated lymphocytic lymphoma, and the third was effaced by a diffuse histiocytic lymphoma. In the fourth case the specimen examined consisted of a spleen also replaced by nodular, poorly differentiate lymphocytic lymphoma. All cases appear to be primary abdominal lymphomas. The structures identified in the four lymphomas were similar in appearance to membrane bound neurosecretory granules when viewed by electron microscopy. It is proposed that the electron dense particles may represent peculiar lysosomes. Further cytochemical examination is needed to adequately characterize them. Although the presence of typical lysosomal granules in normal lymphocytes is a well known finding, we have not seen the type of granules described here i normal lymphocytes. Owing to the frequent use of electron microscopy examination to differentiate small cell undifferentiated (oat cell) carcinomas and, occasionally, other neuroendocrine neoplasms from lymphomas, the finding of these neurosecretory-like structures in lymphomas creates significant difficulty in the differential diagnosis and separation of these neoplasms by ultrastructural analysis.

Black thyroid: clinical manifestations, ultrastructural findings, and possible mechanisms.

Ultrastructural examination of three black thyroid glands showed lysosomal accumulations of lipofuscin-like pigment and granular electron-dense material in association with 1) a minocycline-associated black thyroid with normal thyroid function; 2) a minocycline-associated black thyroid with a significant inflammatory component, fibrosis, and primary hypothyroidism; and 3) a black thyroid gland with no exposure to minocycline. The deposition of the pigments in the three cases resulted in macroscopically recognizable black thyroid glands. It is speculated that an imbalance in lysosomal function accounts for this abnormality. The glandular hypofunction documented in case 2 is unique and confirms the need to monitor function carefully in patients who are receiving minocycline. In one case electrondense deposits were identified in the thyroid gland interstitium.

Growth factors in monoclonal light-chain--related renal diseases.

The immunomorphological expressions of monoclonal light-chain-related renal diseases (MLCRRD) are extremely varied but have a common pathogenetic feature: monoclonal light-chain deposition. The underlying cellular events involved in these processes are likely a reflection of interactions of a complex cascade of inciting and modulating factors. This study explored the potential role of growth factors in MLCRRD by examining the expression of insulin-like growth factor (IGF-I), fibroblast growth factor (FGF), transforming growth factor-beta (TGF-beta), and platelet-derived growth factor A chain (PDGF-A) and B chain (PDGF-B) in 36 cases of MLCRRD. All growth factors examined were expressed in tubules, primarily proximal, but to varying extent. Intensity of IGF-I and TGF-beta tubular staining correlated with tubular injury and interstitial fibrosis. Intensity of tubular staining with antibodies to FGF also correlated with interstitial fibrosis. Platelet-derived growth factor B chain was strongly detected in glomeruli and, in some cases, in vascular structures. Transforming growth factor-beta was detected only in glomeruli of three patients with nodular glomerulopathy associated with light-chain-deposition disease. Insulin-like growth factor, FGF, and PDGF-A were not detected in glomeruli or vessels in any of the cases. Proliferating cell nuclear antigen (PCNA) staining in tubules and glomeruli was markedly increased in light-chain-deposition disease and less but still significantly increased above control values in the other variants of MLCRRD. These results suggested: (1) a correlation between IGF-I and TGF-beta staining in the tubular interstitium and tubular damage; (2) a correlation between IGF-I, TGF-beta, and FGF staining in the tubular interstitium and interstitial fibrosis; (3) a likely important role for PDGF-B activation in certain glomerular alterations that occur in MLCRRD; (4) a role for TGF-beta in light-chain-deposition disease; and (5) the presence of a significant proliferation signal in all cases of MLCRRD but most notably in light-chain-deposition disease in glomerular and tubular compartments. A cascade of events related to growth factor activation appears to play a fundamental role in the pathophysiological processes governing MLCRRD.

Small cell carcinoma of the esophagus: evidence for a unified histogenesis.

Four cases of small cell carcinoma of the esophagus, histologically indistinguishable from oat cell carcinoma of the lung, were studied by electron microscopy. Three were composed largely of small cells with neurosecretory granules characteristic of APUD (amine precursor uptake and decarboxylation) cells. Two of these three cases also contained foci of squamous or glandular differentiation, or both. The fourth case was classified as reserve cell carcinoma with squamous differentiation, since the tumor cells were devoid of neurosecretory granules but contained desmosomes and bundles of intracytoplasmic tonofilaments. The evidence provided by these four cases and also by the 48 cases previously reported in the literature supports our hypothesis that a totipotent primitive cell serves as the common precursor for squamous cell, adeno-, and small cell carcinoma of the esophagus. The latter can be subdivided into oat cell and reserve cell carcinomas, both having the propensity for further squamous and glandular differentiation. The hypothesis can also be applied to lung cancer.

Ultrastructural subtypes of pulmonary adenocarcinoma. A correlation with patient survival.

A retrospective study of 34 patients (33 male and one female) was conducted to evaluate a potential correlation between patient survival, propensity to metastasize and specific subtypes of pulmonary adenocarcinomas as determined by ultrastructural examination. Previous electron microscopic studies of pulmonary adenocarcinomas have demonstrated proliferations of three types of cells: mucus, Clara, and alveolar cells. Specific ultrastructural markers of these cell types were assessed in the 34 cases. All cases in this study had a light microscopic diagnosis of adenocarcinoma originating in the pulmonary parenchyma and a follow-up of at least one year. Features such as patient survival time, extent of metastatic involvement, response to therapy, and overall tumor behavior were compared in reference to the cell of origin, in an effort to try to elucidate if such ultrastructural subclassification lent itself to any clinical correlations. Light microscopic growth patterns and special stains were not found to distinguish these neoplasms histogenetically, emphasizing the important role of electron microscopy for an accurate classification.

The origin of the pseudoglandular spaces in metastatic smooth muscle neoplasm of uterine origin. Report of a case with ultrastructure and review of previous cases studied by electron microscopy.

The entity known as "leiomyomatous hamartoma," a term that has been used in reference to metastatic smooth muscle neoplasms of uterine origin (MSMNUO), is uncommon. Several articles have dealt with clinical and light microscopic aspects of this lesion. Four reports on the ultrastructure of this type of neoplasm have been published, but they have been primarily concerned with its smooth muscle component. Much controversy exists as to whether the glandular elements are part of the neoplastic process or preexisting pulmonary elements. This ultrastructural study confirms that the gland-like spaces represent entrapped alveoli and terminal respiratory bronchioles.

Light microscopic, S-100 immunostaining, and ultrastructural analysis of dermatopathic lymphadenopathy, with and without associated mycosis fungoides.

Thirty-five patients with dermatopathic lymphadenopathy, 12 with (9 patients and 3 follow-up) and 23 without associated mycosis fungoides, and 7 controls with 26 lymph nodes were studied by light microscopic examination and immunostaining for S-100 protein. Fourteen of these cases were examined ultrastructurally. The group of cases studied included lymph nodes obtained at postmortem examination from three patients with mycosis fungoides and evidence of nodal involvement by light microscopic examination. Lymph nodes from patients with dermatopathic lymphadenopathy and paracortical hyperplasia (but no effacement of architecture by recognizable mycosis fungoides cells by light microscopic examination) associated with biopsy-proven mycosis fungoides showed well-defined, diffusely distributed sheets of S-100-positive cells. Cases of dermatopathic lymphadenopathy unassociated with a skin lymphoma (23 cases), with the exception of 3 cases (12.5%), only showed scattered S-100-positive cells, a similar pattern to that noted in normal or reactive lymph nodes from the control cases and reported literature. In the three cases with diffuse sheets without associated mycosis fungoides, the intensity of S-100 staining was the same in germinal centers as in parafollicular areas, while in cases associated with mycosis fungoides, the staining was predominantly in parafollicular zones. Ultrastructural immunolabeling for S-100 protein also revealed different patterns in both subsets of patients. Interestingly, in cases in which the lymph nodes were identified by light microscopic examination to be replaced by mycosis fungoides, the sheets of S-100-positive cells disappeared. The corresponding ultrastructural evaluation showed cellular aggregates with features of T-cells. A combination of S-100 immunocytochemistry and morphologic ultrastructural assessment can be of help in evaluation of lymphadenopathy in patients with mycosis fungoides. Although this study indicates that the finding of sheets of S-100-positive cells in patients with dermatopathic lymphadenopathy is not always associated with mycosis fungoides, the identification of diffuse sheets of S-100-positive cells, especially with parafollicular distribution, in a patient without known T-cell lymphoma should probably be considered an indication to suggest a complete clinical evaluation to rule out the possibility of an undiagnosed mycosis fungoides. The finding of sheets of S-100-positive cells in patients with proven mycosis fungoides may be a morphologic indicator of impending extracutaneous dissemination.

S-100 protein expression by primary and metastatic adenocarcinomas.

S-100 protein has been used as a marker of various lesions, including peripheral nerve sheath, cartilaginous and salivary gland tumors, chordomas, histiocytosis X, and melanomas, among others. The list of neoplasms that can express S-100 protein continues to expand. It has been suggested that staining for S-100 protein may be of aid in the differential diagnosis of amelanotic melanoma versus poorly differentiated tumors. Three hundred fifty primary and metastatic adenocarcinomas from various sites were immunostained for S-100 protein with the use of a commercially available polyclonal antibody. Forty-two percent of the adenocarcinomas tested expressed S-100 protein to varying degrees. The relative incidence of S-100-positive tumors varied with the primary sites, some expressing S-100 protein more often than others. A primary neoplasm able to express S-100 protein was usually associated with metastatic foci also expressing this marker. However, occasionally, a primary S-100-positive tumor was associated with metastasis that lacked expression of S-100. This study emphasizes the importance of testing for a panel of tumor markers in the evaluation of poorly differentiated tumors and cautions on possible difficulties that may arise in the interpretation of immunocytochemistry results.

Cytoplasmic inclusions in hepatocytes of bone marrow transplant patients: light and electron microscopic characterization.

Large eosinophilic, cytoplasmic inclusions were observed at autopsy in the hepatocytes of three patients who received bone marrow transplants for acute leukemia. The eosinophilic inclusions were not associated with any additional specific morphologic change in the liver. While similar inclusions have been observed in rats during hepatic regeneration following partial hepatectomy and in human hepatomas, to the authors' knowledge, such inclusions have not been described previously in patients who have received bone marrow grafts.

In vitro modulation of AL-amyloid formation by human mesangial cells exposed to amyloidogenic light chains.

We have shown in vitro AL-amyloid formation by human mesangial cells (HMCs). AL-amyloid formation may require lysosomal processing of the light chains (LCs) by HMCs for amyloidogenesis to occur. Chloroquine inhibits lysosomal activity. TGF-beta mediates extracellular matrix formation in many glomerulopathies. Thrombospondin (TSP) has been proposed as a mediator of cell proliferation and a marker of early fibrosis. We investigated amyloid formation by HMCs exposed to AL-LCs in the absence of amyloid enhancing factor (AEF). The effects of TGF-beta, TSP and chloroquine on in vitro amyloid formation were studied. HMCs were incubated with two AL-LCs, a light chain deposition disease (LCDD)-LC, or one of two tubulopathic LCs (T-LCs). Additional cells were treated with an AL-LC and chloroquine, TGF-beta, or TSP. Amyloid formation was evaluated microscopically using hematoxylin and eosin, Congo red and Thioflavin-T stains, as well as ultrastructurally. Amyloid was formed only when HMCs were incubated with AL-LCs. Addition of TSP significantly enhanced amyloid formation. In contrast, exogenous TGF-beta and chloroquine significantly attenuated amyloid formation. These findings show that some AL-LCs do not require AEF for amyloidogenesis to occur, and that chloroquine, TGF-beta and sTSP modulate in vitro AL-amyloidosis.

Pigmentosis tubae, a new entity: light and electron microscopic study.

The authors noted an unusual finding in the fallopian tubes of a 31-year-old woman who had received external and internal whole pelvis radiotherapy for squamous cell carcinoma of the cervix. Aggregates of macrophages containing pigment, identified in a subepithelial location, were reminiscent of melanosis coli, which is caused by abuse of anthracene-containing laxatives. Electron microscopic examination of the pigment revealed cytoplasmic material with the appearance of lipofuscin, identical to the pigment described in cases of colonic melanosis. After a careful study of possible etiologic agents, it was concluded that the pigment most likely resulted from cellular damage caused by radiotherapy. The authors are not aware of any other reported case of this entity, which will be called pigmentosis tubae.