Antileukemia activity of perillyl alcohol (POH): uncoupling apoptosis from G0/G1 arrest suggests that the primary effect of POH on Bcr/Abl-transformed cells is to induce growth arrest

In hematopoietic cells, the Bcr/Abl tyrosine kinase that is encoded by the Philadelphia chromosome translocation both stimulates proliferation and activates an anti-apoptotic program that is associated with a G2/M delay upon exposure to various apoptotic stimuli. We recently reported that the monocyclic monoterpene, perillyl alcohol (POH) selectively induces in Bcr/Abl transformed cells, G0/G1 arrest and apoptosis. Therefore, POH activates anti-proliferative and apoptotic pathways against which the Bcr/Abl kinase does not protect. In this report, we show that in Bcr/Abl-transformed cells, POH induces cytoplasmic acidification, redistribution of phosphatidylserine in the plasma membrane along with DNA fragmentation, all of which can be prevented by the phorbol ester, TPA. The ability of TPA to protect against POH-induced cytotoxicity was blocked by inhibitors of protein kinase C (PKC) and the Na(+)/H(+) antiport. In contrast, TPA does not protect the cells from POH-mediated G0/G1 arrest. While POH inhibits a distal step in the mevalonate biosynthesis pathway, lovastatin, also a potential anticancer agent, inhibits the initial step in this pathway. Not surprisingly, lovastatin also induces G0/G1 arrest and apoptosis in Bcr/Abl-transformed cells, however, TPA protects cells from both apoptosis and G0/G1 arrest caused by lovastatin. Thus, in Bcr/Abl-transformed cells, POH and lovastatin cause growth arrest by different mechanisms. Together, these observations demonstrate that POH-mediated cell cycle arrest precedes apoptosis and raises the possibility that that the primary effect of POH is to induce G0/G1 arrest with apoptosis being a consequence of the growth arrest.

Perillyl alcohol selectively induces G0/G1 arrest and apoptosis in Bcr/Abl-transformed myeloid cell lines

The Bcr/Abl tyrosine kinase that is expressed from the Philadelphia chromosome protects leukemia cells from apoptosis caused by removal of growth factors or by cytotoxic agents and ionizing irradiation. This resistance to apoptosis is associated with a Bcr/Abl-mediated G2/M delay. Therefore, inhibiting Bcr/Abl signaling pathways should block the ability of the Bcr/Abl kinase to protect cells from apoptosis. The monoterpenes, limonene and perillyl alcohol (POH) are new anticancer agents that selectively induce apoptosis in neoplastic cells of a variety of rodent carcinoma models. Since the potential antitumor activities of monoterpenes overlap with signaling pathways affected by the Bcr/Abl kinase, POH and limonene were tested for antileukemia activity. POH, but not limonene selectively induced G0/G1 arrest followed by apoptosis in Bcr/Abl-transformed, but not nontransformed FDC.P1 and 32D myeloid cell lines. In contrast to their greater sensitivity to POH, Bcr/Abl-transformed cells were more resistant than nontransformed cells to several chemotherapy agents and ionizing irradiation. Since in Bcr/Abl-transformed cells, POH induces apoptosis associated with G0/G1 arrest, POH must activate an apoptotic pathway that is not protected by the Bcr/Abl-induced G2/M delay. Monoterpenes may represent novel agents for treating Ph+ leukemias.

Recurring proviral integration suggests a role for proto-oncogene activation in thymomas induced with Mo-MuLV-rescued BCR/ABL virus

Intrathymic injection of Moloney murine leukemia virus (Mo-MuLV)-pseudotyped bcr-abl retrovirus (bcr-abl/M) causes thymic lymphoma but only after a prolonged latent period similar to that seen after intrathymic injection of Mo-MuLV alone. Since thymomas induced by Mo-MuLV show recurring proviral integration near certain cellular proto-oncogenes, it was reasoned that if the pathogenesis of bcr-abl/M thymomas is affected by viral integration, then it may be possible to detect proviral insertion near common Mo-MuLV integration sites in bcr-abl-induced thymomas. A panel of thymomas induced by intrathymic injection of Mo-MuLV, Abelson murine leukemia virus (A-MuLV), or the bcr-abl/M virus was analyzed for proviral integration near c-myc, N-myc, Pim-1, and Mlvi-1 loci that are frequently occupied by provirus in Mo-MuLV-induced T cell lymphomas, and for integration near Ahi-1 that is often occupied in A-MuLV/M-induced pre-B cell lymphoma. As expected, thymomas induced with Mo-MuLV showed frequent rearrangements in these loci while thymomas induced with A-MuLV/M (which does not require Mo-MuLV) did not. The bcr-abl/M-induced tumors also showed recurring proviral integration near c-myc, Pim-1 and Mlvi-1, albeit at a lower frequency than seen in the Mo-MuLV tumors. Unexpectedly, four independent thymomas that were clearly of T cell origin demonstrated proviral integration within the Ahi-1 region which was previously thought to only occur in A-MuLV/M induced pre-B cell lymphoma. These observations suggest that recurring proviral insertion in c-myc, Pim-1, Mlvi-1, and Ahi-1 may provide a selective advantage for bcr-abl/M transformed T lymphoid cells. This model may provide a tool for identifying cellular genes that can cooperate with bcr-abl in lymphoid transformation.

Bone marrow stroma-dependent modulation of CD45R isoform expression on Abelson virus transformed pre-B cells

The CD45 glycoprotein family exhibits cell-lineage-associated structural heterogeneity which is due, in part, to alternative pre-mRNA splicing. The Abelson murine leukemia (A-MuLV) preferentially transforms immature B cells that express a B-cell-specific high molecular weight CD45 isoform, called B220. However, we observed that A-MuLV-transformed cell lines are often B220- while maintaining high levels of "pan" CD45 expression. In vitro transformation of murine bone marrow revealed that the stromal microenvironment over which A-MuLV-transformed lymphoblasts are grown affected the B220 phenotype of the pre-B cells. Over a period of a few weeks, B220+ populations grown over a clonal stromal cell line gradually became B220-. However, the transition from a B220+ to B220- phenotype was dependent on the lot of fetal calf serum used. In contrast, cells grown over a heterogeneous bone marrow stroma maintained B220+ expression for long periods of time. The appearance of B220- cells in clonal B220+ populations indicated that the change in phenotype resulted in part from modulation of B220 expression. B220- B-cell lines did not express the high molecular weight CD45 RNA species indicating that the B220- phenotype was due to alternative pre-mRNA splicing. Finally, the shift from B220+ to B220- was not accompanied by changes in the stage of development of the cultures. These observations demonstrate that expression of B220 is not required for the continued proliferation of Abelson-transformed pre-B cells and is regulated by unknown environmental factors.

Increased detection of specific tyrosine phosphoproteins correlates with tumor progression of Abelson virus-infected lymphocytes

Leukemias induced with the v-abl or BCR/ABL oncogene undergo a process of tumor progression which suggests that the ABL oncogene is required but not sufficient for full transformation. In order to identify cellular changes that correlate with progression to full transformation in v-abl transformed lymphoblasts Abelson virus (A-MuLV)-infected murine bone marrow was plated over a pre-established stromal feeder layer. Shortly after A-MuLV infection, transformed lymphoblasts were poorly oncogenic, but over time, progressed in a stepwide manner to a more oncogenic state. The transformants first acquired the ability to grow efficiently in agar, but only over the feeder layer. They next progressed to efficient feeder-independent growth in liquid culture, and then to efficient feeder-independent growth in soft agar. Cell lines that reached the advanced stage of feeder-independent agar growth showed increased detection by antiphosphotyrosine Western blot of the GAP-associated p62 phosphoprotein as well as of a 55 kDa phosphoprotein while detection of the P160 v-abl phosphoprotein remained constant throughout all stages of progression. Although the identity of the p55 phosphoprotein and the mechanism by which detection of p55 and p62 phosphoproteins change on the Western blots during tumor progression are unknown, the data demonstrate that these changes strongly correlate with the stage of progression of v-abl-transformed cells and raise the possibility that these changes may play a role in tumor progression in this model.

Nonrandom cytogenetic changes accompany malignant progression in clonal lines abelson virus-infected lymphocytes

Initially, lymphoid cells transformed by v-abl or BCR/ABL oncogenes are poorly oncogenic but progress to full transformation over time. Although expression of the oncogene is necessary to initiate and maintain transformation, other molecular mechanisms are thought to be required for full transformation. To determine whether tumor progression in ABL oncogene-transformed lymphoid cells has a genetic basis, we examined whether progression of the malignant phenotype of transformed clones correlates with particular cytogenetic abnormalities. A modified in vitro bone marrow transformation model was used to obtain clonal Abelson murine leukemia virus-transformed B lymphoid cells that were poorly oncogenic. Multiple subclones were then derived from each clone and maintained over a marrow-derived stromal cell line for several weeks. Over time, clonally related Abelson murine leukemia virus-transformed subclones progressed asynchronously to full transformation. The data show that tumor progression can occur in the absence of detectable cytogenetic changes but, more importantly, that certain cytogenetic abnormalities appear reproducibly in highly malignant subclones. Therefore, three independent subclones showed deletion in a common region of chromosome 13. Other highly malignant cells carried a common breakpoint in the X chromosome, and, finally, two subclones carried an additional chromosome 5. These results are consistent with the hypothesis that ABL oncogenes are sufficient for the initial transformation of cells but that additional genetic events can drive oncogenic progression. These observations further suggest that diverse genetic mechanisms may be able to drive tumor progression in cells transformed with ABL oncogenes.

Simultaneous expression of RBTN-2 and BCR-ABL oncogenes in a T-ALL with a t(11;14)(p13;q11) and a late-appearing Philadelphia chromosome

Cytogenetic analysis of a pediatric patient with T-cell acute lymphoblastic leukemia (T-ALL) revealed a mosaic karyotype, 47,XX,+17,t(11;14)(p13;q11)/47,XX,+17,t(9;22)(q34;q11),t(11;14) (p13;q11). DNA blot analysis was used to examine the break-point within the BCR gene on chromosome 22 and showed that the breakpoint occurred within the 20-kb minor breakpoint cluster region (m-bcr) located within the first intron of the BCR gene. Immunoprecipitation analysis demonstrated that the leukemic cells expressed the P185 BCR-ABL protein tyrosine kinase. P185 BCR-ABL has previously been shown to be expressed in most cases of Ph+ acute leukemia of myeloid and B-progenitor origin. Here, we demonstrate for the first time that P185 can also be expressed in the T-cell lineage. DNA blot hybridization was also used to characterize the t(11;14) translocation. This showed rearrangement on chromosome 11 within the T-ALLbcr region, upstream of the RBTN-2 gene. Polymerase chain reaction revealed the presence of RBTN-2 transcripts in the leukemic cells. Finally, comparison of the T-ALLbcr, BCR-ABL, IGH, TCR beta and gamma gene rearrangements in leukemic cells obtained at the time of diagnosis and at first relapse showed that relapse occurred in a leukemic clone indistinguishable from the major Ph+ clone involved at diagnosis. Together, these data support a multistep pathogenesis in which the Philadelphia (Ph) chromosome translocation appeared subsequent to the +17 and t(11;14) and imparted a growth advantage over the Ph-negative cells that carried these abnormalities.

Allogeneic T-cell clones able to selectively destroy Philadelphia chromosome-bearing (Ph1+) human leukemia lines can also recognize Ph1- cells from the same patient

Immunocompetent cells in bone marrow allografts have been associated with a graft-versus-leukemia (GVL) effect. To further characterize effector mechanisms that may be involved in this GVL phenomenon, we have previously established an in vitro model to identify allogeneic T-cell clones that selectively mediate cytotoxicity against a patient's leukemic cells, but not against nonleukemic lymphocytes from the same patient. We have modified this in vitro model to test whether the Ph1 chromosome and the P210 fusion protein it controls have a detectable role in leukemia-specific recognition by allogeneic T-cell clones. In this report, T-cell lines reactive with allogeneic Ph1 chromosome-bearing (Ph1+) chronic myeloid leukemia (CML) cell lines were derived and selected to be minimally reactive with Ph1 negative (Ph1-) lymphoid lines from the same patient. However, after prolonged culture, these same T-cell lines also mediated significant destruction of the Ph1- target cells from the same patients. These T-cell lines specifically recognized cells from the allogeneic CML patient to which they were sensitized, and were not contaminated by an outgrowth of natural killer cells. Furthermore, subclones could be derived from these T-cell lines, and some of these subclones again showed selective killing of the allogeneic Ph1+ leukemia cell lines, and not of the Ph1- cell line from the same patient. Analyses of T-cell receptor (TCR) genes showed the alloreactive T-cell lines and the Ph1+ selective subclones derived from them to be of the same clonal origin. This suggests that the same T cells reacting with antigens expressed on the nonleukemic Ph1- targets can at times selectively and preferentially kill the allogeneic Ph1+ cells. As the same TCR that recognizes Ph1+ cells also can recognize the Ph1- targets, it appears that the Ph1+ chromosome does not play a detectable role in recognition by these allogeneic T-cell clones. This in vitro observation may provide a model for evaluating the relationship between GVL and graft-versus-host disease effects.

BCR-ABL and v-abl oncogenes induce distinct patterns of thymic lymphoma involving different lymphocyte subsets

The human BCR-ABL oncogenes encoded by the Philadelphia chromosome (Ph) affect the pathogenesis of diverse types of leukemia and yet are rarely associated with T-lymphoid leukemia. To determine whether BCR-ABL kinases are inefficient in transforming T lymphocytes, BCR-ABL-expressing retroviruses were injected intrathymically into mice. Thymomas that expressed BCR-ABL kinase developed after a relatively long latent period. In most thymomas, deletion of 3' proviral sequences resulted in loss of tk-neo and occasionally caused expression of kinase-active carboxy-terminally truncated BCR-ABL oncoprotein. In contrast, deletion of 3' proviral sequences was not observed in thymomas induced with Abelson murine leukemia virus (A-MuLV). BCR-ABL viruses induced distinct patterns of disease and involved different thymocyte subsets than A-MuLV and Moloney murine leukemia virus (Mo-MuLV). While Mo-MuLV only induced Thy-1+ thymomas, v-abl- and BCR-ABL-induced thymomas often contained mixed populations of B220+ and Thy-1+ lymphocytes in the same tumor. In most v-abl and BCR-ABL tumors, Thy-1+ lymphoid cells expressed CD8 and a continuum of CD4 ranging from negative to positive. Conversely, Mo-MuLV thymomas contained distinct populations of CD4+ cells that were either CD8+ or CD8-. A-MuLV-transformed T-lymphoid cells did not express the CD3/T-cell receptor complex, while BCR-ABL tumors were CD3+. Thus, BCR-ABL viruses preferentially induce somewhat more differentiated T lymphocytes than are transformed by A-MuLV. Furthermore, rare B220+ lymphocytes may represent preferred v-abl and BCR-ABL transformation targets in the thymus.

Simultaneous demonstration of the Philadelphia chromosome in T, B, and myeloid cells

A patient presented with lymphoblastic lymphoma in lymph-nodes and chronic myelogenous leukemia (CML) in narrow and peripheral blood. All marrow and unstimulated peripheral blood cells contained the Philadelphia chromosome[t(9:22)]. Lymphoma cells were analyzed by flow cytometry and were identified as T cells (CD2+CD5+CD7+CD34+). All fresh lymphoma cells contained the t(9:22) translocation. Cultures of purified peripheral blood T and B cells and specifically stimulated NK cells revealed that 59% of the B cells, 10% of the NK cells, and none of the normal T cells contained the translocation. The lack of translocation in normal peripheral T cells is attributed to their long lifespan. No rearrangement of immunoglobulin or T cell receptor beta or gamma genes was found in either the leukemia or lymphoma cells. Analysis of the DNA from cryopreserved lymphoma biopsy showed clonal rearrangement within the common breakpoint cluster region of the bcr gene identical to the bcr rearrangement in DNA from leukemia blood cells. The data support the concept that T and B cells originate in the patient's totipotent stem cell from which the CML is also derived.

Analysis of T cell receptor beta and gamma genes from peripheral blood, regional lymph node and tumor-infiltrating lymphocyte clones from melanoma patients

A total of 199 T cell clones from two melanoma patients were derived from progenitor T cells from recurrent melanoma, regional lymph nodes (either involved or uninvolved with malignancy) and peripheral blood by inoculating single cells directly into the wells of microtiter plates before in vitro expansion. The surface marker phenotype of most clones was CD4+CD8-, although some were CD4-CD8+. Genomic DNA prepared from all clones was analyzed by Southern blot hybridization using T cell receptor (TCR) beta and gamma gene probes, seeking clones with identical TCR gene rearrangement patterns as direct evidence for in vivo progenitor T cell clonal amplification. Probing HindIII-digested DNA with TCR beta and TCR gamma probes revealed several clones with identical TCR gene rearrangement patterns. These clones had subsequent probing of BamHI-digested DNA with TCR beta and TCR gamma probes, which showed all but 2 clones to have distinct rearrangement patterns. These analyses provide clear molecular evidence for in vivo polyclonal CD4+ T cell populations in each of several separate immune compartments in these patients.

P185BCR-ABL in two patients with late appearing Philadelphia chromosome-positive acute nonlymphocytic leukemia

Two patients with acute nonlymphocytic leukemia (ANLL) who had normal karyotypes at diagnosis and developed the Philadelphia (Ph) translocation during leukemia relapse are described in this report. Patient 1 relapsed with Ph-positive acute leukemia, FAB classification M1. The Ig heavy chain locus and T cell receptor gamma and beta genes of relapse cells from this patient were all found to be germline configuration confirming the diagnosis of M1 acute leukemia. Patient 2 displayed a complex karyotypic evolution leading to Ph-positive M4 relapse. Ph-positive relapse specimens from both patients expressed P185BCR-ABL protein and RNA gene products that were identified serologically and by polymerase chain amplification of the BCR-ABL RNA junction. In vitro derived myeloid cell lines from relapse M1 leukemia cells of patient 1 also expressed the P185BCR-ABL protein. In two described patients, late appearance of the Ph translocation that encodes P185BCR-ABL coincided with relapse of acute leukemia. We conclude that P185BCR-ABL may be a strong indicator of Ph-positive acute leukemias.

Comparative biochemical and cytogenetic studies of childhood acute lymphoblastic leukemia with the Philadelphia chromosome and other 22q 11 variants

We studied the relationship of direct karyotypes, determined at diagnosis and remission, to Abelson-related tyrosine kinase activity and the cytogenetic features of erythroid and myeloid colonies derived from remission marrow of six children with acute lymphoblastic leukemia (ALL). These patients had either the characteristic Philadelphia chromosome (Ph1) [t(9;22)(q34;q11)] or cytogenetically similar variants with a 22q11 breakpoint but no detectable cytogenetic involvement of 9q34. The findings suggested two distinct subtypes of ALL: one defined by t(9;22)(q34;q11) and expression of P185BCR-ABL tyrosine kinase and one with variant karyotypes and no P185BCR-ABL expression. The former comprises cases with Ph1 + marrow cells and Ph1 + erythroid and (or) myeloid colonies in remission marrow and others in which the t(9;22) is undetectable in remission marrow cells. In the latter subgroup, the disease may reflect more extreme mosaicism with a similar stem cell that is cytogenetically undetectable. Variant karyotypes included a del(22)(q11) in one patient and a t(6;22;15;9) (q21;q11;q?22;q21) in another; in both instances, the malignant blast cells lacked P185BCR-ABL expression. Thus ALL with t(9;22)(q34;q11) should be distinguished from ALL with other involvement of the 22q11 breakpoint by molecular studies including protein expression. The diversity of karyotypic findings in cases with involvement of 22q11 suggests at least two mechanisms of leukemogenesis in patients with ALL defined by this breakpoint.

Molecular pathogenesis of Ph-positive leukemias

The strong association between the Philadelphia chromosome (Ph) and chronic myelogenous leukemia (CML) suggests that the Ph translocation plays a significant role in CML pathogenesis. For this reason, Ph-positive leukemias have been well studied from the molecular, clinical, and cell biological perspective. We attempt to integrate these data in order to better our understanding of the role of the Ph chromosome in human leukemia.

Diagnosis of chronic myeloid and acute lymphocytic leukemias by detection of leukemia-specific mRNA sequences amplified in vitro

The Philadelphia chromosome is present in more than 95% of chronic myeloid leukemia patients and 13% of acute lymphocytic leukemia patients. The Philadelphia translocation, t(9;22), fuses the BCR and ABL genes resulting in the expression of leukemia-specific, chimeric BCR-ABL messenger RNAs. To facilitate diagnosis of these leukemias, we have developed a method of amplifying and detecting only the unique mRNA sequences, using an extension of the polymerase chain reaction technique. Diagnosis of chronic myeloid and acute lymphocytic leukemias by this procedure is rapid, much more sensitive than existing protocols, and independent of the presence or absence of an identifiable Philadelphia chromosome.

Expression of a distinctive BCR-ABL oncogene in Ph1-positive acute lymphocytic leukemia (ALL)

The Philadelphia chromosome (Ph1) is a translocation between chromosomes 9 and 22 that is found in chronic myelogenous leukemia (CML) and a subset of acute lymphocytic leukemia patients (ALL). In CML, this results in the expression of a chimeric 8.5-kilobase BCR-ABL transcript that encodes the P210BCR-ABL tyrosine kinase. The Ph1 chromosome in ALL expresses a distinct ABL-derived 7-kilobase messenger RNA that encodes the P185ALL-ABL protein. Since the expression of different oncogene products may play a role in the distinctive presentation of Ph1-positive ALL versus CML, it is necessary to understand the molecular basis for the expression of P185ALL-ABL. Both P210BCR-ABL and P185ALL-ABL are recognized by an antiserum directed to BCR determinants in the amino-terminal region of both proteins. Antisera to BCR determinants proximal to the BCR-ABL junction in CML immunoprecipitated P210BCR-ABL but not P185ALL-ABL. Nucleotide sequence analysis of complementary DNA clones made from RNA from the Ph1-positive ALL SUP-B15 cell line, and S1 nuclease protection analysis confirmed the presence of BCR-ABL chimeric transcripts in Ph1-positive ALL cells. In Ph1-positive ALL, ABL sequences were joined to BCR sequences approximately 1.5 kilobases 5' of the CML junction. P185ALL-ABL represents the product of a BCR-ABL fusion gene in Ph1-positive ALL that is distinct from the BCR-ABL fusion gene of CML.

Unique forms of the abl tyrosine kinase distinguish Ph1-positive CML from Ph1-positive ALL

In the Philadelphia chromosome (Ph1) of chronic myelogenous leukemia (CML), the c-abl gene on chromosome 9 is translocated to bcr on chromosome 22. This results in the expression of a chimeric bcr-abl message that encodes the P210bcr-abl tyrosine kinase. The cells of 10% of acute lymphocytic leukemia patients (ALL) carry a cytogenetically similar Ph1 translocation. We report that Ph1-positive ALL cells express unique abl-derived tyrosine kinases of 185 and 180 kilodaltons that are distinct from the bcr-abl-derived P210 protein of CML. The appearance of the 185/180-kilodalton proteins correlates with the expression of a novel 6.5-kilobase messenger RNA. Thus, similar genetic translocations in two different leukemias result in the expression of distinct c-abl-derived products.

Liquid chromatographic determination of guanethidine salts and hydrochlorothiazide using electrochemical detection and ion-pair techniques

A high-performance liquid chromatographic method with amperometric detection utilizing oxidation at the glassy carbon electrode is reported for the quantitative determination of a guanethidine (1)-hydrochlorothiazide (2) mixture. The drug mix is difficult to analyze by a single assay procedure due to large differences in the chemistry and chemical structure of the compounds. The drugs are best separated on an octadecylsilane column using 30:70 acetonitrile:0.05 M aqueous sodium dihydrogen phosphate containing 0.02 M sodium pentanesulfonate (pH 2.5) as the mobile phase at a 1.0 mL/min flow rate. Using a cell potential of +1300 mV versus Ag/AgCl and procaine hydrochloride as the internal standard, calibration curves were established for 1 monosulfate or sulfate and 2 in the 0.5-10 and 1.25-25 micrograms/mL range, respectively. Accuracy and precision of the assay are in the 1.7-6% range. The procedure is shown applicable to the analysis of a combination dosage form and is also useful for either drug in a single component dosage form.

Allogeneic and associative recognition determinants of H-2 molecules

Data presented here describe recent attempts to understand the structural basis for H-2 function. Inbred strains differing only by point mutation in different regions of H-2Kb have proven valuable in the analysis of H-2 domain function. Evidence for the interaction between the N and C1 domains in forming allorecognition determinants and antigen interaction sites is shown. The functional role of C2 is not yet known, since no mutations have been found there, but DNA-mediated gene transfer and exon shuffling techniques should prove invaluable in addressing this issue. Ir gene-type functions of class I molecules were demonstrated. The inability of low responder mutant strains to cross-react with H-2Kb-restricted CTL suggests that these phenomena reflect the failure of virus antigen to interact with low responder H-2Kbm molecules. Thus, the mutant strains provide a valuable system for investigating class I Ir genes.

Expression and function of transplantation antigens with altered or deleted cytoplasmic domains

Two mutants of the class I gene encoding the H-2Ld transplantation antigen have been constructed. In one mutant the cytoplasmic domain of the class I molecule has been altered by deletion of 24 of the 31 C-terminal residues, and in the second the C-terminal 25 residues of the cytoplasmic domain have been replaced with a unique sequence of 19 amino acids. These mutant class I genes have been transferred into mouse L cells by DNA-mediated gene transfer. Both mutant genes are expressed at normal levels on the cell surface, and they have charge properties and sizes consistent with the introduced alterations. These mutant Ld molecules can serve as target antigens for allogeneic cytotoxic T cells and as restricting elements for virus-specific cytotoxic T cells. These results show that the 24 residues replaced or deleted from the carboxy terminus of the class I molecule are not required for its transport to or integration in the plasma membrane, nor for its function as a target antigen or a restricting element during T-cell-mediated cytotoxicity.

Attrition of schistosomes in an irradiation-attenuated cercarial immunization model of Schistosoma mansoni

The attrition of Schistosoma mansoni challenge worms was studied in irradiation-attenuated cercaria-immunized mice as a function of site and time. The peak recovery of schistosomula from the lungs of immunized mice was delayed 2 days in comparison with non-immunized controls. The difference between the peak recoveries of control and immunized mice accounted for about half of the final attrition observed at the 7-week adult worm stge. Hepatic-mesenteric vein worm recoveries obtained 10 to 42 days after challenge were reduced in most cases at least as much as the 49-day counts. Somewhat higher reductions were observed at 14 to 28 days than at 49 days, confirming the evidence of delayed migration obtained at the lung phase. These findings, coupled with histologic observations, indicate that at least half of the worm elimination attributable to immunization occurs 8 or more days after the challenge infection.

Attempts to transfer the resistance of Schistosoma mansoni-infected and irradiated cercaria-immunized mice by means of parabiosis

Acquired resistance to Schistosoma mansoni infection was measured in S. mansoni-infected or irradiated cercaria-immunized mice, and in normal mice to which the former had been surgically joined. Such parabiotic partners were shown to freely exchange humoral and cellular blood constituents. There was no detectable transfer of resistance from mice infected for 8, 12, or 28 weeks to their uninfected partners, even if parabiosis was established before the initial infection and maintained to autopsy. In comparison with parabiosed controls, the number of adult worms surviving from a challenge infection was reduced by 51-96% in the previously infected mice but was not significantly reduced in their uninfected partners. In contrast, mice immunized with irradiated cercariae and their nonimmunized parabiotic partners showed similar levels of resistance. These data indicate that the resistance induced in mice by irradiated cercariae can be transferred, confirm that at least under some experimental conditions the resistance induced in mice by a previous S. mansoni infection is not readily transferred, and provide additional evidence that the resistance induced by normal infection and irradiated cercarial immunization differ in some fundamental way.

Fibroma of tunica albuginea

A case of fibroma of the tunica albuginea is presented with a review of the literature on previously reported cases of this rare entity. The characteristics of this lesion, its pathogenesis, and its treatment are considered.

Cell-mediated immune competence in patients with prostatic carcinoma

The immune competence of 65 patients with prostatic cancer was evaluated by 2 in vivo and 2 in vitro tests to study the contribution of host factors to the progress of the disease. Patients with benign prostatic hypertrophy served as controls. Our results indicate that the delayed skin hypersensitivity response to common microbial recall antigens (streptokinase/streptodornase, purified protein derivative, dermatophytin 0 and dermatophytin) is unaltered in advanced stages of malignancy. The ability to be sensitized by dinitrochlorobenzene declines significantly in patients with metastatic disease. Blastogenic response of peripheral blood lymphocytes to phytohemagglutinin stimulation is not depressed in late stages of malignancy, although in the circulating T cells per cent and absolute values are somewhat lower in patients with metastases. Herein we show that immune competence (measured by the 4 tests) of patients with prostatic carcinoma does not decrease markedly even in the late stages of the disease. Primary sensitization to dinitrochlorobenzene is the only test showing a decline in responsiveness related to the tumor stage.

An unusual solution to complicated prostatic urethral stricture: modified pull-through urethroplasty-urethroneocystostomy

A modified transpubic pull-through procedure was used in a failed Solovov-Badenoch pull-through repair of a traumatic prostatomembranous urethral stricture. The modification consisted of an incision of the intracrural septum through which the mobilized bulbous urethra was then passed and anastomosed to the most available dependent portion of the anterior bladder wall. The outcome was an unexpectedly good result that has persisted for more than 30 months. A review of the literature revealed no absolutely similar procedure.

Neurofibromatosis of the bladder in children: case report and literature review

A case of plexiform neurofibroma of the lower urinary tract is presented as well as a review of all previously reported cases in childhood. We suggest aggressive management in patients with diffuse disease.

Occult sclerosing carcinoma of the thyroid

A case of occult sclerosing thyroid carcinoma is reported. The primary requirement for diagnosis is that the cancer is less than 1.5 cm in diameter. In addition, a fibrosing component with varying degrees of sclerosis is present. Lymph node metastases are frequent and may appear as benign thyroid follicles. Occasional direct invasion or vascular invasion may occur. Distant metastases were not reported in the series reviewed. Adequate therapy would seem to be total thyroidectomy of the involved lobe and radical subtotal thyroidectomy of the opposite lobe with excision of all enlarged or involved lymph nodes.

Treatment of extensive renal calculi with extracorporeal surgery and autotransplantation

Two patients with large calculi in solitary kidneys, treated by ex vivo stone extraction and autotransplantation, are presented. The results show this to be a valuable therapeutic modality for difficult renal calculi where an in situ approach would be hazardous.