The effect of AVP‐V1 receptor stimulation on local GFR in the rat kidney

Aim: Arginine vasopressin (AVP) might influence urinary concentration ability by altering the intrarenal distribution of glomerular filtration rate (GFR). Methods: To study this possibility we have measured the intracortical distribution of GFR following acute AVP‐V₁ receptor stimulation in anaesthetized female Sprague–Dawley (SPD) rats during euvolemia and water diuresis by the aprotinin method, allowing two consecutive measurements of zonal GFR in the same kidney. Results: Acute i.v. bolus injection of 50 ng V₁ receptor agonist ([Phe², Ile³, Orn⁸]‐vasopressin) followed by a continuous infusion of 5 ng min^?1 in euvolemic rats reduced GFR by 25% in outer cortex (OC), 20% in middle cortex (MC) and 19% in inner cortex (IC) relative to vehicle infusion (all P < 0.05). In water diuretic rats V₁ receptor agonist reduced GFR by 22% in OC, 10% in MC and 11% in IC relative to vehicle infusion (P < 0.05). GFR decreased slightly more in OC than in MC and IC in both euvolemic and water diuretic rats (P < 0.05) indicating a distribution of GFR towards MC and IC. Acute infusion of the selective non‐peptide V₁ receptor antagonist OPC‐21268 in euvolemic rats reduced GFR by 14% in OC, 13% in MC and 11% in IC relative to vehicle infusion (P < 0.05), with no significant difference between the layers. Conclusions: The change in distribution of GFR not only between OC and IC, but also between OC and MC suggests that the afferent/efferent arterioles and not the medullary vasa recta is the main site of resistance change. We conclude that acute i.v. infusion of V₁ receptor agonist in high doses reduces GFR more in superficial than in deep cortex in both euvolemic and water diuretic rats and that this may be of some importance for water conservation, adding to the V₂‐ receptor effect on water permeability of the collecting ducts.     

A distinctive glomerular lesion complicating placental site trophoblastic tumor: report of two cases

Renal disease with distinctive pathologic features developed in two young women who had placental site trophoblastic tumors. The renal abnormalities were manifested by proteinuria in both cases and by hematuria in one case; blood pressure was elevated in one of the patients. Pathologic examination of the kidneys showed distinctive glomerular abnormalities, characterized mainly by the presence of occlusive eosinophilic deposits in many of the glomerular capillary lumina, most of which stained for fibrinogen-related antigens and IgM by immunohistochemical techniques. Ultrastructural examination showed the deposits to consist mainly of granular material that contained packets of fibrillar material with the appearance of fibrin. The uterine tumors were composed of mononucleated and multinucleated cells with abundant cytoplasm that infiltrated between the muscle bundles of the myometrium; in both tumors there was prominent deposition of eosinophilic material that had the tinctorial properties of fibrin and that stained for fibrinogen and IgM in immunoperoxidase studies. The renal abnormalities disappeared after hysterectomy in one case; the other patient, who was receiving chemotherapy and had disseminated intravascular coagulation, died with leukopenia and sepsis. The clinical and pathologic features in these cases suggest that the renal abnormalities were related to the uterine tumors and that the production of immune complexes and/or the activation of intravascular coagulation by the tumors were pathogenetic mechanisms.     

Coreceptor Switch of [MLV(SIVagm)] pseudotype vectors by V3-loop exchange

Retroviral vectors derived from murine leukemia virus (MLV) have been pseudotyped with a variant of the envelope glycoprotein (Env) of nonpathogenic simian immunodeficiency virus from African green monkeys (SIVagm) to result in [MLV(SIVagm-wt)] vector particles. The variant env gene encodes a full-length surface envelope glycoprotein (SU) and a C-terminally truncated transmembrane protein (TM). To change the coreceptor usage of this vector from CCR5 to CXCR4, which is predominant on human CD4-positive lymphocytes, the putative V3-loop of SIVagm SU was replaced by that of the T cell tropic HIV-1 variant BH10. The resulting [MLV(SIVagm-X4)] vectors were shown to specifically transduce CD4/CXCR4-positive cell lines, demonstrating the equivalent function in cell entry and choice of coreceptor usage of the V3-loops of SIVagm and HIV-1. These modified vectors were able to transduce primary human lymphocytes and were resistant to neutralization by sera from HIV-1-infected individuals. The [MLV(SIVagm-X4)] pseudotype vector generated is thus a promising candidate vector, e.g., for in vivo gene therapy of HIV-1 infection.     

人类免疫缺陷病毒包膜糖蛋白V3区对细胞结合能力的研究

目的：研究人类免疫缺陷病毒（ＨＩＶ）不同亲嗜株包膜糖蛋白Ｖ３区结合于靶细胞的能力。方法：合成来源于不同嗜性ＨＩＶ－１Ｖ３区的生物素标记和非标记的多肽。采用流式细胞计数分析生物素化的 Ｖ３多肽对细胞的结合能力以及细胞表面的结合配体。结果：ＨＩＶ－１Ｘ４　亲嗜株ＩＩＩＢＶ３区能结合于多种细胞的表面，包括辅助受体ＣＸＣＲ４；竞争实验结果显示蛋白酶抑制剂能抑制该结合。Ｒ５亲嗜株 ＡＤＡ Ｖ３区只极微弱地结合于外周血单核细胞和表达ＣＣＲ５ 的人星形胶质细胞表面。结论：不同嗜性ＨＩＶ－１Ｖ３区结合于细胞表面的能力不同从亲嗜株Ｖ３区直接结合于细胞表面并被其自身所增强，其靶分子至少包括辅助受体 ＣＸＣＲ４和蛋白酶分子；而Ｒ５亲嗜株 ＡＤＡ Ｖ３区则不结合于 ＣＣＲ５和蛋白酶。     

Preferential apoptosis of CD56dim natural killer cell subset in patients with cancer

Natural killer (NK) cells (CD56(+)/CD3(-)) in the circulation of cancer patients were reported to have low NK activity and undergo spontaneous apoptosis. A possible relationship between apoptosis and impaired NK activity was studied by Annexin V-binding and NK-cell assays performed with peripheral blood mononuclear cells of patients with head and neck cancer (HNC), breast cancer (BC) and normal controls (NC). Cells stained with Annexin V (Anx) and antibodies to CD56, CD3, CD95, CD25, CD122 or CD132 were examined by flow cytometry. NK activity was tested against K562 targets in 4-h (51)Cr-release assays. The ratio of CD56(dim)/CD56(bright) NK cells was significantly different in patients vs. controls (10 vs. 16; p<0.01). A significantly greater percentage of CD56(dim) NK cells bound Anx in HNC patients (27+/-17%, median +/- SD) or BC (46+/-18%) than in NC (15+/-18%, p<0.04 and p<0.0002, respectively). CD56(dim) NK cells were preferentially targeted for apoptosis. NK activity was significantly lower in patients with HNC and BC than in NC (p<0.009). An inverse correlation between NK activity and the percent of Anx(+)CD56(dim) NK cells was observed in cancer patients (p =0.002) but not in NC. In patients, circulating CD56(dim) NK cells were targeted for apoptosis, leading to low levels of NK activity.     

A monoclonal antibody that blocks class II histocompatibility-related immune interactions

Previous studies using conventional hetero- or isoantisera have indicated the involvement of class II (Ia) molecules in presentation of soluble by monocytes to inducer T lymphocytes, stimulation of inducer T cells in MLR, and recognition of Ia-bearing targets cells by cytotoxic T lymphocytes (CTL). The experience in using monoclonal anti-Ia reagents capable of blocking these phenomena in the human system is limited. Recently, however, we have characterized a lytic IgG2a monoclonal antibody, 9–49, that binds to functionally significant class II molecules. This antibody blocks (in the absence of complement): (1) specific binding of peripheral blood lymphocytes (PBL) to antigen-pulsed monocyte monolayers, (2) proliferation of PBL in response to soluble antigen (tetanus toxoid or mumps) or cell surface class II antigen stimulation in allogeneic or autologus MLR, (3) proliferation of cloned T4+ (inducer) lymphocyte cell lines to class II antigens, (4) generation of cytotoxic lymphocytes during allogenic MLR, and (5) recognition (and killing) of class II-bearing target cells by T4+ CTL clones. Proliferation and CTL activity of a T8+ clone is unaffected by the 9–49 antibody. These results indicate the usefulness of this monoclonal reagent in studies evaluating the functional role of Ia molecules in immune recognition phenomena.     

Significance of fibrils in the formation of the Kimmelstiel-Wilson nodule

Summary The pathogenesis of the nodular lesion in diabetic glomerulosclerosis is described in association with fibrils. Thirteen diabetic patients with glomerular nodular lesions and 9 diabetics without the nodules were examined by electron microscopy using periodic acid-thio-carbohydrazide-silver proteinate staining. In cases of nodular glomerulosclerosis, abundant fibrillar structures mixed with electron-dense material were detected within the nodule and the mesangial matrix. They were also occasionally observed along the subendothelial space of the glomerular capillary walls. On the cross-section, these fibrils, including the lucent periphery, were 34 nm wide. Immunohistologically, collagen V and collagen VI were detected in nodular lesions. In contrast, in cases of the diffuse type of glomerulosclerosis, the widened mesangium was composed of dense material, which resembled the original mesangial matrix. The above fibrils were not detected in the mesangium. These findings suggest that the accumulation of the peculiar fibrils in the glomerular mesangium is a major pathogenic factor in the formation of Kimmelstiel-Wilson nodules.     

T suppressor lymphocytes reverse ongoing acute allograft rejection

(LEW X BN)F1 cardiac allografts are rejected within 8 days in untreated LEW recipients. At the critical time point of 5 days after transplantation, the obviously rejecting grafts are enlarged and maximally infiltrated by host cells as shown by 111In-labeled lymphocyte tracer studies. However, when such hearts were retransplanted back to naive (LEW X BN)F1 secondary hosts, they survive indefinitely, showing that even late rejection is reversible in the absence of sustained host immunological drive. Attempts were then made to abrogate this advanced immune responsiveness using Cyclosporine (CsA). CsA therapy (15 mg/kg/day for 7 days) starting from day 5 produced indefinite graft survival, similar as if initiated at the time of operation. Addition of exogenous IL-2, which drives the proliferation of Tc, could not reverse this effect. Serial changes in phenotype of lymphocyte subpopulations infiltrating both acutely rejecting and indefinitely functioning cardiac allografts in unmodified and CsA treated hosts, respectively, were then studied. Ratio of Th:Tc/s cells in acutely rejecting grafts was 1.6 by day 3; it inverted abruptly to 0.7 by day 5-6, suggesting predominance of Tc/s during the later stages of allograft rejection. Similarly, treatment with CsA produced a transient depression of Th, with recovery of original Th:Tc/s ratio during the next 2-3 weeks. Adoptive transfer experiments were then performed to investigate the functional significance of these findings.(ABSTRACT TRUNCATED AT 250 WORDS)     

Recombinant avian oncoviruses. II. Alterations in the gag proteins and evidence for intragenic recombination.

The internal structural (gag) proteins of recombinant avian oncoviruses selected for the env gene of RAV-O (an endogenous chicken virus) and the src gene for PR-RSV-C were examined. Eight of ten clones of such recombinants were found to synthesize altered gag proteins. The gag proteins of one recombinant clone, PR-E-95c, were examined in more detail by gel electrophoresis and tryptic peptide mapping. These methods have allowed us to distinguish between the gag proteins of the two parental viruses and to determine from which virus the proteins of the recombinant virus were derived. PR-E-95c virions were found to contain p27₀, an electrophoretically distinguishable variant of p27 which is found in isolates of RAV-0. This recombinant virus also contains p12/15, which is electrophoretically indistinguishable from the p12/15 of both of the parental viruses. However, tryptic peptide analysis of p15 indicates that PR-E-95c has inherited PR-RSV-C-specific p15 sequences. These observations suggest that at least one cross-over has occurred between p15 and p27 in PR-E-95c. A striking difference between the proteins of PR-E-95c virus and those of the parental viruses is that the recombinant lacks polypeptides migrating in the position of p19 and contains two novel polypeptides termed p19α (MW 20,000) and p19β (MW 15,000). Both of these polypeptides are phosphorylated and share antigenic determinants and some tryptic peptides with parental p19. As determined by peptide analysis and radioimmunoassay, these p19-related proteins contain information from both parental viruses, suggesting that PR-E-95c has another cross-over within p19. The altered p19 proteins bind to viral RNA specifically and are associated with genomic RNA in the virion. Neither the stability nor the specific infectivity of the recombinant viruses appears to be significantly affected by the altered proteins.     

Genetics of reovirus: the relationship of interference to complementation and reassortment of temperature-sensitive mutants at nonpermissive temperature.

Temperature-sensitive mutants of reovirus type 3 are capable of interfering with the replication of wild-type reovirus type 3. The interfering activity correlated with the ability of pairs of mutants to complement at 39°: Pairs of noninterfering mutants (tsD × tsE) yielded efficient complementation (indexes of 10–50); pairs of interfering mutants (including members of groups ts A, B, G) did not produce significant complementation (indexes ～ 1). The ability of pairs of mutants to reassort at 39° generally followed a similar pattern. Thus interference is an important property of ts mutants of reovirus and needs to be considered when genetic interactions are being studied at 39°.