Effects of ecologically relevant concentrations of cadmium in a freshwater fish.

Sub-chronic effects of ecologically relevant concentrations of cadmium (Cd) were evaluated in the catfish Rhamdia quelen. The fish were exposed to Cd (0, 0.1, 1, 10 and 100µgL(-1)) for 15 days. Bioconcentration was observed in the liver of fish exposed to 10 and 100µgL(-1) of cadmium. The liver glutathione S-transferase activity decreased at 0.1 and 1µgL(-1) and increased at 100µgL(-1) and lipoperoxidation increased in all tested concentrations. Fish exposed to 0.1, 1 and 100µgL(-1) Cd presented increase in hepatic lesion index. In the kidney, the catalase activity and LPO reduced in all exposed groups. The gluthatione peroxidase, etoxiresorufin-O-deethylase activities and metallothionein increased at the highest concentration of Cd, but the level of reduced glutathione decreased. The genotoxicity was observed at 0.1 and 100µgL(-1). Neurotoxicity was not observed. The results showed that low concentrations (range of µgL(-1)) of Cd caused hepato-, nephro- and hematological alterations in this freshwater fish species.

Nonneoplastic pineal cysts: a clinicopathologic study of twenty-one cases.

Twenty-one cases of nonneoplastic pineal cyst are presented. The patients were 13 women and 8 men, with a median age of 33 years. Sixteen patients were symptomatic. Symptomatic cysts had an average size of 16.5 mm. In most cases, symptoms and signs were related to increased intracranial pressure, cerebrospinal fluid obstruction, neuroophthalmologic dysfunction, brainstem and cerebellar compression, and mental status changes. Uncommon clinical presentations in three cases were related to increased cyst size caused by hemorrhage, sudden death, and postural syncope and loss of consciousness. Imaging studies showed a uniform hypodense or hypointense, nonenhancing pineal mass with occasional peripheral calcification and associated with hydrocephalus, aqueductal compression, tectal deformity, and hemorrhage within the cavity, in decreasing order of frequency. Fourteen patients underwent open cyst resection. Histologically, the intact lesions show a unilocular or multilocular cavity, surrounded by a wall comprised of variable amounts of glial tissue, remnants of pineal gland, and an external fibrous capsule. Follow-up information showed 12 patients alive and well without recurrence between 26 and 144 postoperative months. One patient who underwent stereotactic drainage had a recurrence. One symptomatic patient who did not have surgery died suddenly of causes related to the cyst. The present study supports the role of surgical excision for the treatment of symptomatic pineal cysts to obtain adequate tissue for diagnosis and relief of symptoms. The use of histochemical and immunohistochemical studies may prove useful in the distinction of these lesions with astrocytomas and cystic pineal parenchymal tumors.

Immunization with cholesterol-rich liposomes induces anti-cholesterol antibodies and reduces diet-induced hypercholesterolemia and plaque formation.

Immunization of rabbits with a protein-free formulation consisting of liposomes containing 71% cholesterol and lipid A as an adjuvant induced anticholesterol antibodies that caused complement-dependent lysis of liposomes lacking lipid A. The antibodies, immunoglobulin G (IgG) and immunoglobulin M (IgM), also recognized nonoxidized crystalline cholesterol as an antigen by enzyme-linked immunosorbent assay (ELISA). The effects of immunization against cholesterol on elevations in serum cholesterol and development of atherosclerosis were examined in rabbits fed a diet containing 0.5% to 1.0% cholesterol. Although the mean serum cholesterol level, mainly in the form of very-low-density lipoprotein cholesterol, rose as much as 60-fold in the nonimmunized rabbits, the elevation was significantly less--as much as 35% lower--in the immunized rabbits. Elevation of serum cholesterol was accompanied by an apparent drop in the level of antibodies on initiating the diet, followed by a rebound on stopping the diet, thus suggesting that the antibodies were adsorbed to cholesterol that was present in circulating lipoproteins. When lipoprotein fractions--composed of either very-low-density and intermediate-density lipoproteins derived from cholesterol-fed nonimmunized rabbits or human low-density lipoproteins--were tested as capture antigens by solid-phase ELISA, reactivity was observed with IgG and IgM antibodies present in the serum of immunized rabbits. Immunization also resulted in a marked decrease in the risk of developing atherosclerosis. Analysis of aortic atherosclerosis by quantitative histologic examination and fatty streaks by automated morphometric probability-of-occurrence mapping showed diminished atherosclerosis in most areas of the aorta in vaccine recipients. It is proposed that immunization with liposomes containing 71% cholesterol and lipid A can reduce diet-induced hypercholesterolemia and atherosclerosis.

Proliferation of renal cell carcinoma assessed by fixation-resistant polyclonal Ki-67 antibody labeling. Correlation with clinical outcome.

BACKGROUND: Although tumor staging is an important prognostic parameter for renal cell carcinoma (RCC), postnephrectomy survival interval is often difficult to predict for individual patients. This is the result of varied growth characteristics, which in tumors of similar stage govern both time to recurrence and rate of tumor dissemination. Polyclonal Ki-67 antibody labels a proliferation-specific antigen expressed in actively proliferating cells and is applicable to formalin fixed paraffin embedded archival tissue. This study was designed to test the prognostic utility of Ki-67 antigen labeling in a series of RCC and to compare the data with those derived from other markers of cell proliferation. METHODS: Polyclonal Ki-67 antibody staining of 206 cases of RCC was undertaken using the streptavidin-biotin method. Cases were grouped according to Ki-67 indices and Kaplan-Meier survival curves were constructed. Groups were compared in terms of survival for all cases and for each of Robson's stages using the log rank test. Further sections were stained for proliferating cell nuclear antigen (PCNA) and silver-staining nucleolar organizer regions (AgNORs). The prognostic significance of Ki-67 antigen, PCNA and AgNOR staining, histologic grade, and tumor stage were compared using Cox's proportional hazard model. RESULTS: Ki-67 immunostaining was achieved for 173 cases with indices ranging from 0.1% to 30.4%. Division of tumors with indices 6% or less and greater than 6% showed a significant difference in survival between groups for all cases and for each Robson stage. Ki-67 and PCNA indices, AgNOR scores, and tumor dissemination (Robson Stage 3 and 4) retained a significant association with survival on multivariate analysis. CONCLUSIONS: Polyclonal Ki-67 antibody immunostaining provides significant survival information that complements that derived by other markers of cell proliferation and tumor staging.

Tumors of pineal parenchymal cells: a correlation of histological features, including nucleolar organizer regions, with survival in 35 cases.

We studied 35 parenchymal neoplasms arising in the pineal gland, including 11 pineoblastomas, 21 pineocytomas, and three mixed pineocytoma-pineoblastomas. Pineoblastomas were most commonly found in children (mean age, 12.6 years). The median postsurgical length of survival for seven patients, including five with remote metastases, with fatal outcome was 24 months. The 21 pineocytomas were found in older individuals (mean age, 26.8 years). Four patients with pineocytoma died; two before surgery and two in the immediate postoperative period. The remaining 17 patients survived for intervals between 6 and 118 months after surgery. Two mixed pineocytoma-pineoblastomas were found in infants who died a few months after biopsy, whereas a third patient, an adult, was alive at 46 months after excision and irradiation. Both pineoblastoma and pineocytoma exhibited variable immunoreactivity to neurofilament proteins, synaptophysin, glial fibrillary acidic protein, S-100 protein, retinal-S antigen, and rhodopsin; the highest percentages of positive cells stained with synaptophysin. Three pineocytomas exhibited ganglionic differentiation and two of them also showed a glial component. Prognosis could not be correlated with the degree of divergent differentiation. Comparison of silver-stained nucleolar organizer region (AgNOR) counts between pineoblastomas and pineocytomas suggests that the former are more actively proliferative than the latter, with mixed pineocytoma-pineoblastoma showing intermediate activity. There was no correlation between AgNOR score and prognosis within the three tumor groups.

Computerized nuclear morphometry and survival in renal cell carcinoma: comparison with other prognostic indicators.

Morphometric nuclear parameters were compared with patient survival for a series of 174 renal cell carcinomas (RCC) collected over a 30 yr period. Stepdown regression showed long diameter, average feret diameter, form factor and the ratio of average feret diameter to equivalent diameter to be significantly associated with survival. Nuclear area, nuclear perimeter, equivalent diameter, ratio of long diameter to average feret diameter and coefficients of variation of nuclear area and nuclear perimeter were not significantly correlated with survival. All parameters were correlated with a 3 division nuclear grading classification using analysis of variance. Multivariate analysis showed nuclear form factor, tumor stage, silver staining nucleolar organizer region numbers and proliferating cell nuclear antigen expression to be independently associated with survival. The results of this study indicate that form factor is the most discriminate morphometric parameter for RCC, providing survival data additional to that derived from tumor staging and from markers of tumor proliferation.

Systemic lymphadenopathic histology in human immunodeficiency virus-1-seropositive drug addicts without apparent acquired immunodeficiency syndrome.

We examined lymph nodes from multiple sites in 50 individuals infected with human immunodeficiency virus (HIV-1) who died accidentally of drug overdoses and in whom there was no evidence of opportunistic infection. The size, histologic pattern, presence of Warthin-Finkeldey-type giant cells, and estimation of CD4 cell count of these lymph nodes were compared with those of 13 seronegative drug addicts (controls). Lymph nodes from seropositive individuals were slightly but significantly larger than those of controls. Lymph nodes from seropositive cases were much more likely to contain secondary follicles (90%) than were those from controls (20%). Unlike follicles in control nodes, most secondary follicles in the seropositive cases were in various stages of fragmentation and involution. As follicular changes progressed, there was a decrease in CD4 cells and an increase in intrafollicular and paracortical plasma cells. Plasmacytosis was much more prevalent in lymph nodes from seropositive individuals than in controls. Warthin-Finkeldey-type giant cells were present in at least one node in 29 of 50 seropositive cases, were most numerous in those showing follicular hyperplasia with fragmentation (45% of cases), and were especially numerous in Peyer's patches (61% of cases). There was generally good concordance of HIV-1-associated follicular morphology among diverse lymph node groups. There is prolonged generalized, mild hyperplastic lymphadenopathy with frequent syncytial cells in intravenous drug addicts with asymptomatic HIV-1 infection.

Infectivity of titered doses of simian immunodeficiency virus clone E11S inoculated intravenously into rhesus macaques (Macaca mulatta).

The macaque infectious dose (MID) of a single-cell clone of simian immunodeficiency virus isolated from a pig-tailed macaque (SIV/Mne clone E11S) was determined in rhesus macaques (Macaca mulatta). Twenty-one macaques were inoculated with 10-fold dilutions of the virus stock (three or four animals per dose). The virologic and clinical status of these animals was monitored for 26 weeks. The 25% MID (MID25) occurred at a 10(5)-fold dilution of the viral stock.

Proliferating cell nuclear antigen (PCNA) expression as a prognostic indicator for renal cell carcinoma: comparison with tumour grade, mitotic index, and silver-staining nucleolar organizer region numbers.

Proliferating cell nuclear antigen (PCNA) expression in renal cell carcinoma (RCC) was determined by immunohistochemical staining using the PC10 clone. PCNA indices ranged from 2.4 to 53.1 per cent with mean indices of 12.6, 19.0, and 31.6 per cent for grades 1 to 3 RCC and 31.9 per cent for sarcomatoid RCC. There was a significant difference between the indices of grades 1 and 3 and grades 2 and 3 tumours and between grades 1 and 2 RCC and sarcomatoid RCC. AgNOR scores and mitotic indices were determined for each tumour and comparison of PCNA indices with mean AgNOR scores and mitotic indices showed only a weak correlation (PCNA/AgNOR r = 0.406, PCNA/mitotic index r = 0.315). Tumours were divided according to PCNA index (< or = 18 per cent and > 18 per cent) and there was a significant difference in survival between the two groups, for all cases, and for each of the Robson stages. Multivariate analysis using Cox's proportional hazard model showed PCNA index, tumour stage, and mean AgNOR score to be independent predictors of survival, while tumour grade and mitotic index were found to be dependent variables.

Postmortem localization of HIV-1 RNA by in situ hybridization in lymphoid tissues of intravenous drug addicts who died unexpectedly.

The histopathological alterations in lymphoid tissues and the presence of human immunodeficiency virus (HIV-1) RNA were studied in 25 consecutive autopsies of seropositive, apparently asymptomatic, intravenous drug overdose victims without palpable lymphadenopathy. The majority of lymphoid tissues in a given person showed either a combination of follicular hyperplasia and fragmentation or a combination of involution and depletion. Individuals with involuted and depleted lymphoid tissues were significantly older than those individuals with hyperplasia and fragmentation of follicles. Lymph nodes from individuals with hyperplasia with or without fragmentation were slightly but significantly larger than control nodes from seronegative persons. In tissues from infected cases, HIV-1 RNA was demonstrated by in situ hybridization in 49% of follicular centers showing hyperplasia, 62% of hyperplastic fragmented follicles, and 66% of involuted follicles in a distribution of follicular dendritic cells. No signal was detected in tissues demonstrating follicular depletion or nodes from seronegative persons. Scattered inter- and intrafollicular lymphoid cells with positive signal were present only in nodal tissues with follicular hyperplasia without involution. Tonsils, inguinal, axillary, mediastinal, supraclavicular, mesenteric nodes, and spleen were positive for HIV-1 RNA in 78%, 76%, 67%, 65%, 58%, 50%, and 28% of cases, respectively, and the prevalence of positivity reflected the presence of follicles. We conclude that the clinically asymptomatic period of HIV-1 infection is characterized by pathological stages in lymphoid tissues that have distinct histological alterations and distribution of viral RNA.

Massive covert infection of helper T lymphocytes and macrophages by HIV during the incubation period of AIDS.

Animal and human lentiviruses elude host defences by establishing covert infections and eventually cause disease through cumulative losses of cells that die with activation of viral gene expression. We used polymerase chain reaction in situ double-label methods to determine how many CD4+ lymphocytes are latently infected by human immunodeficiency virus (HIV) in patient lymph nodes and whether the pool of infected cells is large enough to account for immune depletion through continual activation of viral gene expression and attrition of cells responding to antigens. We discovered an extraordinarily large number of latently infected CD4+ lymphocytes and macrophages throughout the lymphoid system from early to late stages of infection, and confirmed the extracellular association of HIV with follicular dendritic cells. Follicular dendritic cells may transmit infection to cells as they migrate through lymphoid follicles. Latently infected lymphocytes and macrophages constitute an intracellular reservoir large enough ultimately to contribute to much of the immune depletion in AIDS, and represent a difficult problem that must be resolved in developing effective treatments and protective vaccine.

Analysis of human immunodeficiency virus-infected tissues by amplification and in situ hybridization reveals latent and permissive infections at single-cell resolution.

Latent and productive viral infections are at the extremes of the spectrum of virus-cell interactions that are thought to play a major role in the ability of such important human pathogens as human immunodeficiency virus (HIV) to elude host defenses and cause disease. The recent development of PCR-based methods to amplify target sequences in individual cells in routinely fixed tissues affords opportunities to directly examine the subtle and covert virus-cell relationships at the latent end of the spectrum that are inaccessible to analysis by conventional in situ hybridization techniques. We have now used PCR in situ with in situ hybridization to document latent and permissive HIV infection in routinely fixed and paraffin-embedded tissue. In one of the first specimens we examined, a tumor biopsy from an HIV-infected individual, we found many of the lymphocytes and lymphocytes infiltrating the tumor had HIV DNA that was detectable only by PCR in situ. The fraction of positive cells varied regionally, but there were foci where most of the cells contained HIV DNA. Most of these lymphocytes and macrophages are latently infected, as we could detect HIV RNA in fewer than one in a thousand of these cells. We also detected HIV RNA, surprisingly, in 6% of the tumor cells, where the number of copies of viral RNA per cell was equivalent to productively infected cell lines. The alternative states of HIV-gene expression and high local concentration of latently infected lymphocytes and monocytes revealed by these studies conceptually supports models of lentiviral pathogenesis that attribute persistence to the reservoir of latently infected cells and disease to the consequences of viral-gene expression in this population. The magnitude of infection of lymphocytes documented in this report is also consistent with the emerging view that HIV infection per se could contribute substantially to depletion of immune cells in AIDS.

Intracranial meningioma with pulmonary metastasis in three dogs.

Extracranial metastasis of primary central nervous system neoplasms is uncommon and has not been described in the dog. We report the clincopathologic features of intracranial meningioma with pulmonary metastasis in three dogs (case No. 1: 13-year-old castrated male Boxer dog; case No. 2: 14-year-old spayed female Dachshund; case No. 3: 6-year-old spayed female German Shepherd Dog). Case No. 1 presented with ataxia, lethargy, vomiting, and leaning and falling to the right, and had a transient remission following radiation and corticosteroid therapy; case No. 2 had a history of seizures that were unresponsive to primidone, left-sided postural reaction deficits, ataxia, and circling to the right; case No. 3 had only intermittent episodes of vomiting Computed tomography of case Nos. 1 and 2 revealed peripherally located homogeneous contrast-enhancing intracranial masses. Postmortem examination revealed intracranial masses with single or multiple pulmonary nodules in all three cases. Histologically, the intracranial and pulmonary masses were meningotheliomatous meningiomas with atypical features including brain infiltration, necrosis, nuclear atypia, prominent nucleoli, and moderate cell density. All of the primary meningiomas had low mitotic rates. The current interest in early diagnosis and aggressive clinical/surgical management of canine patients with meningioma and other primary central nervous system neoplasms will likely result in an increased detection of extracranial metastases.

No direct neuronotoxicity by HIV-1 virions or culture fluids from HIV-1-infected T cells or monocytes.

Macrophages and microglia are the principal target cells for human immunodeficiency virus (HIV) in brain, and as such, are likely participants in the neuropathology of HIV infection. In a model system for this process, we found that fluids from human monocyte cultures enhanced survival and differentiation of the neurons in fetal rat brain explants. In contrast, fluids from HIV-infected monocyte cultures were strongly toxic to neurons and paradoxically enhanced the proliferation of glial cells. Further, neuronotoxic activity in these fluids was mediated through activation of NMDA binding receptors on the neurons and was inhibited by any of several different NMDA antagonists. Neuronotoxic activity was directly related to contamination of the HIV virus stock with Mycoplasma arginini and M. hominis. Pure cultures of mycoplasma, bacterial lipopolysaccharide (LPS), or murine recombinant tumor necrosis factor alpha (rTNF alpha) each induced neuronotoxicity which exactly mirrored that induced by the contaminated HIV stock. It is likely that mycoplasma or components of the mycoplasma plasma membrane stimulate TNF alpha production by the glial cells in the brain explants. Indeed, careful depletion of glial cells in these explants prevented mycoplasma or LPS-mediated neuronotoxicity. No neuronotoxicity was evident with HIV-1 virus stock, HIV-1 gp120, or culture fluids from HIV-infected T cells or monocytes when these preparations were free of contamination by mycoplasma and LPS. These findings suggest caution in interpretation of those experiments in which similar contamination has not been rigorously excluded.

Cystic papillary meningioma in the sella turcica of a dog.

An 8-year-old spayed Scottish Terrier was examined because of a history of intermittent abnormal behavior that progressed to hind limb ataxia and eventually to recumbency with opisthotonos. X-Ray computed tomography revealed a radiolucent mass in the area of the hypothalamus. At necropsy, a suprasellar cystic papillary meni-ngioma was identified. The unusual clinical signs of disease and computed tomographic findings of this case complicated diagnosis.

Primary angiosarcoma of the central nervous system. Study of eight cases and review of the literature.

Angiosarcoma arising in the central or peripheral nervous system has rarely been reported. Eight patients with primary angiosarcoma of the central nervous system are described here; these included five males and three females ranging in age from 2 weeks to 72 years (mean 38 years). Of the eight neoplasms, six were located in the cerebral hemispheres and one was in the meninges; the site was unknown in the other. All patients underwent surgical resection. Five of the eight patients died, four within 4 months after surgery and one after 30 months. Two of the remaining three patients were 17 and 27 years old at the time of diagnosis and were alive at follow-up review 39 and 102 months after surgery, respectively. One patient was lost to follow-up monitoring. Microscopically, all eight tumors demonstrated a well-differentiated pattern with irregular vascular channels and intraluminal papillae; in addition, four showed poorly differentiated solid areas. Immunohistochemical staining of neoplastic cells to factor VIII-related antigen and Ulex europaeus agglutinin I was performed in five tumors and was focally positive in four. No correlation could be shown between the histological features and the growth and biological behavior of the tumors.