Immunogenetic control of brain tumor growth in rats.

The susceptibility to intracerebral and s.c. growth of a transplantable gliosarcoma in genetically inbred rats correlated with histocompatibility type. The genetic control of tumor growth was tested in a cross between a tumor-susceptible strain (F344, Ag-B1) and a tumor-resistant strain (YO, Ag-B2). Susceptibility was transmitted as a dominant trait, and at least two genes or gene complexes were involved: one was linked to the major histocompatibility complex and one segregated independently of it. The genetic mechanisms did not appear to be affected significantly by the site (environment) in which the tumor grew. Antibodies to Ag-B1 histocompatibility antigens, which were those of the strain in which the tumor originated (F344), and to tumor-associated antigens were generally present in animals in which the tumor had regressed. Only tumor-specific antibodies appeared in the sera of Ag-B1 animals that had the tumor. A cytotoxic lymphokine was present in the sera of tumor-bearing animals, but its level did not correlate with tumor growth or regression.

Kinetics of early HIV-1 gene expression in infected H9 cells assessed by PCR.

The time course of viral gene expression in H9 cells acutely infected with HIV-1 was analysed by the polymerase chain reaction (PCR). Virus-specific sequences were first detected in genomic DNA of H9 cells 1-2 h after infection. RNA for the regulatory genes such as the tat and nef appeared 2-3 h post-infection and RNA for the gag and env at 3 h. The results demonstrate that viral DNA synthesis occurs rapidly after infection of target cells followed by synthesis of viral RNA. Cell-associated reverse transcriptase activity increased after 24 h, while culture supernatant enzyme activity increased later, between 1-5 days. The delay in virus release after rapid integration and transcriptional activity suggests the involvement of additional factors, perhaps both cellular and viral, that control the formation and budding of mature virions.

Evaluation of monoclonal antibodies to HIV-1 envelope by neutralization and binding assays: an international collaboration.

OBJECTIVE: To characterize a purified panel of monoclonal antibodies (MAb) to epitopes in HIV-1 envelope V3, CD4-binding region, C4 and gp41. DESIGN: Neutralization and/or binding activity data were obtained from 21 laboratories on a coded panel consisting of seven human MAb, seven mouse MAb, recombinant human CD4 immunoadhesin [CD4-immunoglobulin G (IgG)], normal human and normal murine Ig. METHODS: Laboratories performed a variety of neutralization assays and antigen binding assays with HIVIIIB, HIVMN and other laboratory strains of HIV-1. RESULTS: For a single MAb, there was up to a 10(3) range of neutralizing antibody titers between laboratories. The range in titers appeared to depend on the sensitivity of the neutralization assay. Two methods were used to consolidate the data from all laboratories, the geometric mean titer (GMT) and the median neutralizing titer (MNT). The panel of MAb were also analyzed by a variety of assays that measure binding activity to native or denatured epitopes. The relative binding activity of the MAb did not appear to correlate with neutralizing activity. CONCLUSION: Neutralization results from any single laboratory did not correlate with the collective data. The relative potency (rank order) of the MAb in the panel were equivalent when determined by GMT or MNT. These values may be useful to individual laboratories for estimating the sensitivity of their neutralization assays. The study also identified potential reference reagents with which neutralizing activity could be compared.

Immunogenetic aspects of transplantation in the rat brain.

The nature of the brain as an immunologically privileged site is controversial. Using congenic rats, we have demonstrated that grafts that differ from the recipient in the A locus of the MHC produce sensitization following intracerebral transplantation, thus indicating that the brain is not immunologically privileged. The IC grafts show histologic signs of rejection, which are delayed compared with the changes found in the subsequent orthotopic grafts, suggesting that the immune response is weaker in the brain.

Myxomatous degeneration of the mitral valve complicated by nonbacterial thrombotic endocarditis with systemic embolization.

Myxomatous degeneration of the mitral valve is a disease of unknown etiology that is associated with many ominous complications. A case in which non-bacterial thrombotic endocarditis, superimposed on a myxomatous mitral valve, resulted in systemic embolization to the brain, heart, and kidney is presented. The purpose of this report is to describe a serious and previously unreported complication of myxomatous degeneration of the mitral valve.

Pathogenesis of Pichinde virus infection in strain 13 guinea pigs: an immunocytochemical, virologic, and clinical chemistry study.

Pichinde virus has been adapted to produce lethal infection of Strain 13 guinea pigs. Viral replication and presence of viral antigen in frozen tissues stained by immunofluorescence has been previously described. Further investigation into the pathogenesis of this disease has been hampered by the lack of a light microscopic method for correlating histologic lesions and the presence of Pichinde viral antigens. For this purpose, we developed a sensitive immunocytochemical technique for staining Pichinde viral antigens in formalin-fixed, paraffin-embedded tissue. Enhancement of the immunocytochemical staining with nickel chloride markedly improved detection of viral antigens. We examined frozen and formalin-fixed tissues from Strain 13 guinea pigs for viral antigens by light microscopy and immunocytochemistry at various intervals after infection with Pichinde virus. Progressive involvement of different tissues correlated with organ injury measured by serum biochemical abnormalities. Pichinde viral antigen was first detected in splenic macrophages five days after infection and their subsequent destruction facilitated persistent viremia. The inability to clear virus led to multiple organ infection and vascular involvement. Ensuing infections involved particularly the liver, spleen, adrenal glands, lungs, and intestines. Gastroenteritis developed, with extensive involvement of the muscularis mucosa throughout the gastrointestinal tract. Water and food intake decreased rapidly after day 8, leading to marked weight loss. Fatty changes of the liver suggested metabolic derangement that was further exacerbated terminally by adrenal infection and pulmonary impairment.

Localized lymphoid relapse in the pancreas following allogeneic hematopoietic stem cell transplant for chronic myelogenous leukemia.

The incidence of isolated extramedullary disease (EMD) following allogeneic hematopoietic stem cell transplant (allo-HSCT) for chronic myelogenous leukemia (CML) is not fully known. One review found the incidence of isolated myeloid EMD, or granulocytic sarcoma (GS), in an allo-HSCT treated CML/myelodysplastic subgroup to be just 0.22%. The incidence of lymphoid EMD in similar patients is extremely rare with only two cases reported in the literature. While the etiology of EMD in the post-transplant setting is not entirely clear, there may be inefficacy of immune surveillance function outside of the bone marrow cavity. Isolated CML GS following allo-HSCT carries a median interval to bone marrow relapse between 7 and 10 months and a median survival of 12 months. Less is known about lymphoid EMD. The treatment in these cases is ill defined with modalities ranging from involved field radiation to second allo-HSCT. We present a case of isolated pancreatic lymphoid EMD diagnosed 15 months after allo-HSCT for CML. Our patient was also treated with withdrawal of his immunosuppressive regimen. Unfortunately, at just over 4 months following pancreatic resection, he developed systemic relapse and died. While EMD can occur anywhere in the body, CML associated pancreatic EMD is not previously reported.

Dopamine b-Hydroxylase: Determination of half-life and appearance in lymph fluid after IV injection of 125 I-DBH into rats.

A 4 day half-life of dopamine beta-hydroxylase (DBH) was determined for rats injected IV with 125I-rat DBH from the slow exponential component of radioactivity appearing in plasma, urine, feces and combined urine and feces. Half-life estimates for 125I-rat DBH injected IV into WKY and SHR animals did not differ from Sprague Dawley (Zivic Miller) rats. Radioactivity declined in parallel in plasma, urine and feces following IV 125I-rat DBH administration and each radioactivity falloff curve could be resolved into two components. The slow phase of the decline of radioactivity excreted into urine and feces from which DBH half-life was calculated occurred between 5 and 25 days after 125I-rat DBH injection. The early fast phase which is associated with distribution of the exogenous protein in body fluids and tissues continued for approximately the first 140 hr after DBH injection. The distribution characteristics of IV administered active bovine DBH and 125I-rat DBH into the lymphatic system were examined. After active bovine DBH or 125I-rat DBH was injected IV into rats, active DBH or radioactivity, respectively, appeared in lymph fluid (thoracic duct) within 20 min; reached peak concentrations within 90 min, and thereafter, declined in parallel with the plasma concentration. The concentration of radioactivity in plasma and lymph fluid were found to be unequal at 9 hr but were equivalent 68-75 hrs after IV injection of 125I-rat DBH. Based on the amount of active DBH or radioactivity which accumulates in lymph fluid it is clear that a substantial amount (greater than 50%) of the DBH in blood circulates through the lymphatic channels. Analysis of parallel experiments with labelled serum albumin indicate that use of these methods to study plasma proteins do provide sensitive measures of biological half-life and lymphatic distribution characteristics. Specifically for DBH, the results of our study suggest that DBH normally circulates in plasma and lymph fluid with a biological half-life of 4 days.

Urinalysis and urinary sediment in patients with renal disease.

Examination of the urine plays a vital role in the diagnosis of kidney diseases. Proteinuria is an important indicator of renal disease and the types of proteins found in the urine help distinguish glomerular and tubular disorders. The findings of casts and blood cells in the urine provide valuable clues about the causes of the underlying renal pathology. Crystals may be found in the urine of healthy individuals and in patients with urolithiasis, toxic damage, and chronic renal failure.

Unilateral multinodular toxic goiter: scintiscan mimicking solitary toxic nodule.

A 58-year-old man presented with hyperthyroidism. By palpation, the left lobe of the thyroid was diffusely enlarged, and the right lobe was normal. Radioactive iodide scintiscan demonstrated homogeneous uptake that was localized to the enlarged left lobe, with near total suppression of uptake on the right. TSH stimulation led to clear visualization of a normal appearing right lobe, findings most consistent with an autonomously functioning solitary nodule on the left. Left hemithyroidectomy cured the hyperthyroidism. However, no single dominant nodule was found in the left lobe. Rather, there was diffuse thyroidal hyperplasia of the micronodular variety, consistent with multinodular toxic goiter. Thus, in this patient with a usually diffuse form of thyroid disease, the autonomously functioning hyperactive follicles were localized predominantly to one thyroid lobe. This variant expands the clinical spectrum of multinodular toxic goiter, and further emphasizes the extent of asymmetry in the distribution of hyperactive follicles than can occur in this disorder.

Opportunistic Trichosporon pneumonia. Association with invasive aspergillosis.

Two severely immunocompromised patients suffered extensive pulmonary infection with Trichosporon cutaneum (T beigelii) and Aspergillus species. In one patient, the T cutaneum demonstrated yeast forms in tissue sections. The other patient had T cutaneum fungemia prior to death, and examination of lung tissue demonstrated both yeast and hyphal forms. To our knowledge, these patients are the first described with polymycotic infection involving T cutaneum and Aspergillus species. Trichosporon cutaneum must be added to Candida, Torulopsis, and Cryptococcus species as a cause of visceral opportunistic yeast infection.

Laboratory systems failure: the enemy may be us.

Vendors might not always be to blame when laboratory information systems fail to meet expectations. Too often, those who use the system haven't devoted the time or resources to create a system that meets their needs, or truly learn a system that may already have all the bells and whistles necessary for success.

Implementing an effective point-of-care testing program.

The implementation and management of a point-of-care testing program requires the effective cooperation of nurses, pathologists, other physicians, technologists, and vendors. These individuals working collectively must establish the clinical and financial bases for establishing a program, for managing its daily operation, and for assuring its ongoing quality and value to patient care.

Immunogenetic aspects of intracerebral skin transplantation in inbred rats.

This study was undertaken to evaluate the ability of intracerebral skin grafts transplanted across different genetic disparities in the major histocompatibility complex (RT1) to elicit an immune response in inbred rats, as determined by histologic examination and by the ability of the grafts to sensitize the recipients to subsequent orthotopic skin grafts. The ability of intracerebral skin allografts to sensitize rats to transplantation antigens is related to the specific genetic disparity between the graft and the host: sensitization appears to occur more consistently across an A region barrier than across a B region barrier. Histologic changes of intracerebral graft rejection are more severe in rats with two intracerebral grafts than in those with one. The degree of histologic change attributable to intracerebral allograft rejection correlates with the ability of these grafts to sensitize the recipient. In certain strains intracerebral sensitization is accomplished with two grafts but not with one, indicating an antigenic dose requirement for intracerebral sensitization.

Immunogenetic and immunologic aspects of gliosarcoma growth in rats.

Growth of the chemically induced, transplantable rat brain tumor gliosarcoma 9L (GS-9L) is under immunogenetic control. Both susceptible and resistant rats produce an immune response to the tumor, but the response is qualitatively different in the two groups. The intraperitoneal administration of gliosarcoma-9L cells in resistant KGH rats causes the production of cytotoxic lymphocytes and macrophages, and in susceptible F344 rats suppressor lymphocytes are produced. After gliosarcoma-9L cells were administered to (KGH x F344)F1 and backcross rats, tumor susceptibility or resistance and the nature of the immune response correlated well with the histocompatibility type, indicating the parallel genetic control of both traits. However, a second gene or gene complex, not linked to the major histocompatibility complex, may participate in the regulation of tumor growth.