Experimental autoimmune encephalomyelitis develops in CC chemokine receptor 7-deficient mice with altered T-cell responses

CC chemokine receptor 7 (CCR7) is involved in the initiation of immune responses by mediating the migration of naïve T cells and mature dendritic cells to T-cell-rich zones of secondary lymphoid organs where antigen presentation occurs. To address whether CCR7 plays a role in the development of autoimmunity, we induced experimental autoimmune encephalomyelitis in CCR7-deficient mice on a C57BL/6 background (CCR7(-/-)) using the neuroantigen, myelin oligodendrocyte glycoprotein 35-55 amino acid peptide (MOG((35-55))) and Bordetella pertussis toxin (PTX). CCR7(-/-) mice acquired disease with an intensity similar to wild-type littermates. MOG((35-55))-specific lymphocyte responses were dominant in the spleen of CCR7(-/-) mice, rather than in lymph nodes as observed in wild-type mice. These results indicate that effective immune responses (with altered kinetics) can develop in the absence of CCR7 but develop in the spleen rather than lymph nodes as CCR7 is necessary for T and dendritic cells to enter lymph nodes.

Molecular characterization of human adenomyosis

Adenomyosis is a common gynaecological disorder characterized by the abnormal growth of endometrium into the myometrium and myometrial hypertrophy/hyperplasia. Uterine fibroids are benign neoplasms of the myometrium, and they represent a diagnostic pitfall for adenomyosis. In this study, we have used the genome-wide Affymetrix U133 Plus 2.0 microarray platform to compare the gene expression patterns of adenomyosis, uterine fibroids, normal endometrium and myometrium. Unsupervised principal component analysis (PCA) revealed that these four tissue types could be segregated from one another solely based on their gene expression profiles. Analysis of variance (ANOVA), followed by Tukey means separation test, significance analysis of microarrays (SAM) and 2-fold change threshold, identified 7415 probe sets as differentially expressed among the four groups of samples. Supervised cluster analysis based on these probe sets clustered adenomyosis most closely with endometrium and uterine fibroids with myometrium, consistent with the anatomic origin of these two diseases. The Tukey means separation post hoc testing found 2073 probe sets altered between adenomyosis and normal endometrium or myometrium, and 2327 probe sets altered in expression when comparing uterine fibroids with myometrium. Using Ingenuity Pathways Analysis (IPA), we found 9 highly significant functional networks in adenomyosis and 10 in uterine fibroids. Notably, the top network in both cases was associated with functions implicated in cancer and cell death. Finally, we compared the gene expression profiles of adenomyosis and uterine fibroids and identified 471 differentially expressed probe sets that may represent potential biomarkers for the differential diagnosis of these diseases.

Bacteriophage T7 RNA polymerase transcription elongation is inhibited by site-specific, stereospecific benzo[c]phenanthrene diol epoxide DNA lesions

Benzo[c]phenanthrene diol epoxide (B[c]PhDE), the ultimate carcinogenic metabolite of the environmental pollutant benzo[c]phenanthrene, reacts with DNA primarily at the exocyclic amino groups of purines, forming B[c]PhDE-DNA adducts that differ in their stereochemical configurations and their effect on biological processes such as transcription. To determine the effect of these stereoisomers on RNA synthesis, in vitro T7 RNA polymerase transcription assays were performed using DNA templates modified on the transcribed strand by either a site-specific (+)-trans- or (-)-trans-anti-B[c]PhDE-N(6)-dA lesion located within the sequence 5'-CTCTCACTTCC-3'. The results show that both (-)-trans-anti-B[c]PhDE-N(6)-dA and (+)-trans-anti-B[c]PhDE-N(6)-dA block RNA synthesis. Furthermore, both B[c]PhDE-dA stereoisomeric adducts lead to lower levels of initiation of transcription relative to that observed using an unmodified DNA template. In contrast to these results, placement of the adduct on the nontranscribed strand within the template does not impede transcription elongation. In addition to the assessment of the effect of the lesions on transcription elongation, the resulting transcripts were characterized in terms of their base composition. A high level of base misincorporation is detected at the 3'-ends of truncated transcripts, with guanosine being most frequently incorporated opposite the modified nucleotide rather than the expected uridine. This result supports the notion that translocation past a modified base in a DNA template relies in part on correct base incorporation, and suggests that stalling of RNA polymerases at damaged sites in DNA may well be dependent on both the presence of the lesion and the base which is incorporated opposite the modified nucleotide.

Gene transfer to suppress bone marrow alkylation sensitivity

Alkylating agents represent a highly cytotoxic class of chemotherapeutic compounds that are extremely effective anti-tumor agents. Unfortunately, alkylating agents damage both malignant and non-malignant tissues. Bone marrow is especially sensitive to damage by alkylating agent chemotherapy, and is a dose-limiting tissue when treating cancer patients. One strategy to overcome bone marrow sensitivity to alkylating agent exposure involves gene transfer of the DNA repair protein O(6)-methylguanine DNA methyltransferase (O(6)MeG DNA MTase) into bone marrow cells. O(6)MeG DNA MTase is of particular interest because it functions to protect against the mutagenic, clastogenic and cytotoxic effects of many chemotherapeutic alkylating agents. By increasing the O(6)MeG DNA MTase repair capacity of bone marrow cells, it is hoped that this tissue will become alkylation resistant, thereby increasing the therapeutic window for the selective destruction of malignant tissue. In this review, the field of O(6)MeG DNA MTase gene transfer into bone marrow cells will be summarized with an emphasis placed on strategies used for suppressing the deleterious side effects of chemotherapeutic alkylating agent treatment.

DNA repair methyltransferase (Mgmt) knockout mice are sensitive to the lethal effects of chemotherapeutic alkylating agents

We have generated mice deficient in O6-methylguanine DNA methyltransferase activity encoded by the murine Mgmt gene using homologous recombination to delete the region encoding the Mgmt active site cysteine. Tissues from Mgmt null mice displayed very low O6-methylguanine DNA methyltransferase activity, suggesting that Mgmt constitutes the major, if not the only, O6-methylguanine DNA methyltransferase. Primary mouse embryo fibroblasts and bone marrow cells from Mgmt -/- mice were significantly more sensitive to the toxic effects of the chemotherapeutic alkylating agents 1,3-bis(2-chloroethyl)-1-nitrosourea, streptozotocin and temozolomide than those from Mgmt wild-type mice. As expected, Mgmt-deficient fibroblasts and bone marrow cells were not sensitive to UV light or to the crosslinking agent mitomycin C. In addition, the 50% lethal doses for Mgmt -/- mice were 2- to 10-fold lower than those for Mgmt +/+ mice for 1,3-bis(2chloroethyl)-1-nitrosourea, N-methyl-N-nitrosourea and streptozotocin; similar 50% lethal doses were observed for mitomycin C. Necropsies of both wild-type and Mgmt -/mice following drug treatment revealed histological evidence of significant ablation of hematopoietic tissues, but such ablation occurred at much lower doses for the Mgmt -/- mice. These results demonstrate the critical importance of O6-methylguanine DNA methyltransferase in protecting cells and animals against the toxic effects of alkylating agents used for cancer chemotherapy.

Incorrect base insertion and prematurely terminated transcripts during T7 RNA polymerase transcription elongation past benzo[a]pyrenediol epoxide-modified DNA

DNA replication and transcription are affected adversely by the presence of bulky adducts that are generated by the covalent binding of a variety of metabolically activated environmental pollutants to cellular DNA. When these lesions are not cleared by cellular repair enzymes prior to replication, mutations and ultimately tumor initiation can occur. Transcription and DNA repair appear to be intimately connected, since certain adducts are more efficiently removed from the transcribed strands of active loci than from non-transcribed strands and other quiescent domains in the genome. The mechanism by which RNA polymerases deal with bulky adducts during DNA transcription is therefore of great interest. The availability of site-specifically modified and stereochemically defined oligodeoxyribonucleotides derived from the covalent reaction of 7r, 8t-dihydroxy-9, 10t-epoxy- 7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE) with guanine residues prompted us to study the efficiencies of transcription past these lesions using bacteriophage T7 RNA polymerase. We show here that T7 RNA polymerase can bypass such lesions in a DNA template, providing that a cytosine residue is incorporated opposite anti-BPDE-modified guanine. However, when an incorrect base (most frequently a purine) is inserted opposite the modified site, the RNA polymerase stalls, and the complex dissociates, resulting in a truncated transcript. The ability of the T7 RNA polymerase to discriminate between a correct and an incorrect inserted base and, accordingly, to continue or terminate transcription, might constitute an important mechanism that ensures the fidelity of transcription past a modified base present on the transcribed strand of the DNA template.

Predictors of increased mitral regurgitation after percutaneous mitral balloon valvotomy

Left ventriculography (LVG) was performed to assess severity of mitral regurgitation (MR) on a scale of 0-4+ in 157 patients before and immediately after percutaneous mitral balloon valvotomy (PMV). There were 129 women and 28 men aged 51 +/- 1 (range 13-87) yr. With PMV, mitral valve area increased from 0.9 +/- 0.1 cm2 to 2.0 +/- 0.1 cm2 (P less than .0001). Increase in mitral regurgitation (MR) occurred in 69 patients (44%). Patients were divided into two groups based on increase in MR after PMV. Group A (n = 136) had 0-1+ increase in MR. Group B (n = 20) had greater than or equal to 2+ increase in MR after PMV. The only predictor of increase in MR greater than or equal to 2+ was the ratio of effective balloon dilating area to body surface area (EBDA/BSA). EBDA/BSA was 4.0 +/- 0.1 cm2/m2 in Group A vs. 4.37 +/- 0.2 cm2/m2 in Group B (P = .02). Follow-up of patients in Group B showed: Four patients remained NYHA Class III and required mitral valve replacement 4.3 +/- 1.1 (range 5-21) mo after PMV. One patient who had undergone combined aortic and mitral valvotomy died in the hospital of worsening heart failure. One patient died 1 mo later of sepsis related to a dental abscess. Follow-up of the remaining 14 patients at 9.5 +/- 1.1 (range 2-7) mo showed 10 in NYHA Class I and four in NYHA Class II. Eight of 15 patients (53%) who had repeat left ventriculogram at 9.0 +/- 0.8 mo after PMV had a decrease in MR of one grade when compared to LVG immediately after PMV.

Percutaneous aortic balloon valvuloplasty: its role in the management of patients with aortic stenosis requiring major noncardiac surgery

Seven patients with severe aortic stenosis underwent percutaneous aortic balloon valvuloplasty in preparation for major noncardiac surgery. There were four men and three women (mean age 82 +/- 1.3 years, range 78 to 88). A significant reduction in the transaortic pressure gradient from 77 +/- 7.8 to 31 +/- 6.2 mm Hg (p = 0.002) and increase in calculated aortic valve area from 0.5 +/- 0.1 to 1.0 +/- 0.3 cm2 (p = 0.05) was noted. Three of the seven procedures were performed anterograde with use of transseptal puncture: two of the three because of abdominal aortic aneurysm and one because of peripheral vascular disease. All seven patients underwent uncomplicated noncardiac surgery under general anesthesia 10 +/- 4.3 days (range 0 to 29) after aortic valvuloplasty. One patient had exploratory laparotomy, one underwent stabilization of a hip fracture and two underwent resection of an abdominal aortic aneurysm. Of the three other patients who underwent colectomy, one had repeat aortic valvuloplasty and repair of a hip fracture 7 months later and one required exploratory laparotomy without repeat valvuloplasty 7 weeks later. Percutaneous aortic balloon valvuloplasty is an effective and safe procedure that may reduce the risk of general anesthesia and major noncardiac surgery in elderly patients with aortic stenosis.

Renal cholesteatoma

Renal cholesteatoma is being reported more frequently in the literature. A case with a twenty-year documented history is presented, together with observations on differential diagnosis.

Medical decision making for the incompetent patient

In America competent adult patients have a right to refuse unwanted medical treatments. For incompetent patients who have made no advance directive, the family ordinarily makes decisions about medical treatments. But in many healthcare facilities, problems arise in choosing a surrogate to make decisions for an incompetent patient and in working with that surrogate. Concrete, step-by-step procedures for resolving conflict are needed. Every effort should be made to have competent patients fill out advance directives or indicate their treatment preferences in the event of loss of competence. Family members may not override decisions made by competent patients, but anyone closely involved with the patients' care may question their competence. The physician generally assesses the patients' competence, but sometimes the courts are involved. The physician may be the appropriate person to choose a surrogate for a patient with limited competence or to make decisions for a totally incompetent patient. The surrogate may be a relative, close friend, physician who knows the patient well, or someone provided by the hospital or government. Treatment decisions are made within the surrogate-patient-physician triad. When different value judgments about the proper treatment conflict, the surrogate may have to mediate to restore physician-patient communication, or institutional proceedings through the ethics committee may be needed to resolve disputes quickly, amicably, and at low cost. As a last resort, the case may be referred to the courts.

Institutional ethics committees: what, how, and why

Because institutional ethics committees can reduce the risk of tragic mistakes by clinical decision makers and provide interdisciplinary input into decisions, they may be a requirement for all hospitals by the end of this decade. Ethics committees should not in themselves be decision-making entities, however. Their proper functions are to advise physicians, patients, and families; facilitate communication; provide in-house education; assist in policy formulation; mediate between ethical theory and concrete medical judgments as well as between the institution's values and those of the larger community; provide support for those involved in painful decisions; and minimize the institution's vulnerability to litigation. Although ethics committees have been endorsed by federal agencies, a presidential commission, and numerous health care organizations, several obstacles remain. Physicians are afraid that their decisional prerogatives will be wrested from them; a committee could become a rubber-stamp organ for one powerful member, one special-interest group, or one perspective, confidentiality policies would have to be extended to nonhospital committee members; and medical personnel feel threatened by the exposure of errors or bad judgment. Nonetheless, ethics committees are a promising structural adjustment to ethical pressures exerted by new technology and the growing number of health care disciplines.

Regression of prostatic cancer metastasis by high doses of diethylstilbestrol diphosphate

Diethylstilbestrol diphosphate (DES-P) has shown effective symptomatic relief in patients with metastatic carcinoma of the prostate. Although there is little known about its role in soft tissue metastasis, our experience in 3 patients with advanced carcinoma of the prostate infiltrating the trigone and ureterovesical junction revealed significant improvement of hydronephrosis. All patients failed to respond to conventional doses of stilbestrol. Diethylstilbestrol diphosphate is recommended in the treatment of advanced carcinoma of the prostate with soft tissue metastasis. It is safe and effective, and the tumor responses outweigh the side effects of the drug. The mechanism of action of this compound is discussed.

Complete duplication of urethra

Complete duplication of the urethra with a single bladder is an exceptional finding. The anomalous urethral canal originates from the bladder separately, runs parallel and usually dorsal to the normally situated urethra, and opens on the dorsum of the penis. To our knowledge there are 41 reported cases of this anomaly. We present 2 cases of complete urethral duplication originating from a single bladder, one in a male patient and the other in a female. It is concluded that conservative therapy is the treatment of choice, and that surgery should be reserved for incontinent patients only. The complications of surgery have been emphasized.