Hemifacial spasm due to a large distant ipsilateral posterior fossa meningioma

A rare case of hemifacial spasm due to an ipsilateral foramen magnum/clival meningioma is described. Magnetic resonance imaging demonstrated that the tumor was located distant to the cranial nerve VII/VIII complex. Resolution of the ipsilateral hemifacial spasm was noted after complete resection of the tumor. The mechanism of hemifacial spasm was likely due to displacement and distortion of the brain stem from the lesion distant to the cranial nerve VII/VIII complex. In our review of the literature this is the first reported case of an ipsilateral posterior fossa meningioma causing hemifacial spasm from indirect mass effect.

Gonadotropin-releasing hormone and its receptor in normal and malignant cells

Gonadotropin-releasing hormone (GnRH) is the hypothalamic factor that mediates reproductive competence. Intermittent GnRH secretion from the hypothalamus acts upon its receptor in the anterior pituitary to regulate the production and release of the gonadotropins, LH and FSH. LH and FSH then stimulate sex steroid hormone synthesis and gametogenesis in the gonads to ensure reproductive competence. The pituitary requires pulsatile stimulation by GnRH to synthesize and release the gonadotropins LH and FSH. Clinically, native GnRH is used in a pump delivery system to create an episodic delivery pattern to restore hormonal defects in patients with hypogonadotropic hypogonadism. Agonists of GnRH are delivered in a continuous mode to turn off reproductive function by inhibiting gonadotropin production, thus lowering sex steroid production, resulting in medical castration. They have been used in endocrine disorders such as precocious puberty, endometriosis and leiomyomata, but are also studied extensively in hormone-dependent malignancies. The detection of GnRH and its receptor in other tissues, including the breast, ovary, endometrium, placenta and prostate suggested that GnRH agonists and antagonists may also have direct actions at peripheral targets. This paper reviews the current data concerning differential control of GnRH and GnRH receptor expression and signaling in the hypothalamic-pituitary axis and extrapituitary tissues. Using these data as a backdrop, we then review the literature about the action of GnRH in cancer cells, the utility of GnRH analogs in various malignancies and then update the research in novel therapies targeted to the GnRH receptor in cancer cells to promote anti-proliferative effects and control of tumor burden.

Prospective randomized studies for carotid endarterectomy

The clinical trial has become the standard method used to evaluate surgical procedures. Regarding carotid endarterectomy, clinical trials have reformed the indications for surgery as a means of decreasing the risk of stroke. The methodology and results from significant trials for the symptomatic and asymptomatic patient with carotid stenosis are described. Critical evaluation of these trials is necessary for the discerning surgeon to form a rational approach to clinical practice in carotid disease.

Depletion of CD34+ CD4+ cells in bone marrow from HIV-1-infected individuals

Pancytopenia as a consequence of bone marrow abnormalities is commonly seen in HIV-infected individuals. To examine the effect that HIV-1 has on hematopoietic cells, we compared hematopoietic properties of bone marrow samples from HTV+ patients at various stages of disease with bone marrow samples from uninfected donors. While the absolute number of recovered CD34+ cells and the cloning efficiency of these cells did not differ significantly in HIV+ donors, the percentage of CD34+ CD4+ cells was significantly depleted in late-stage HIV+ patients. We observed a direct correlation between the numbers of CD34+ CD4+ cells in the bone marrow and the peripheral CD4 count. Further characterization of the CD34+ CD4+ subpopulation demonstrated that these cells expressed lower levels of HLA-DR on their surface compared with CD34+ CD4- cells, suggesting an immature phenotype. We also found evidence for expression of HIV-1 coreceptors CXCR-4 and CKR-5 message and protein in CD34+ bone marrow cells. While this finding suggested that hematopoietic cells might be susceptible to HIV infection at an early stage of maturation, thus affecting different cell lineages as they matured, we did not find any evidence for infection of HIV in these cells. These data suggest that HIV affects early hematopoietic progenitor cells either directly or indirectly, and in particular CD34+ CD4+ cells. This finding has important implications for disease pathogenesis and for application of gene therapy approaches that use CD34+ hematopoietic cells.

Diphtheria toxin A gene-mediated HIV-1 protection of cord blood-derived T cells in the SCID-hu mouse model

The reconstitutive potential of CD34+-derived cord blood (CB) cells, transduced with a regulated diphtheria toxin A (DT-A) chain gene, was examined in SCID-hu mice harboring a conjoint organ composed of human thymus and liver (thy/liv). The DT-A-transduced cells, injected directly into the thy/liv organ, showed the same engraftment potential as control CB cells transduced with the non-DT-A parental vector. CB cells, distinguishable from the thy/liv cells by the HLA marker B7, were preferentially maintained in ex vivo culture. In the thy/liv organ, the engrafted CB cells represented >80% of the total cells. A majority of cells (>70%) in the thy/liv organ were also CD4+CD8+, as would be expected of maturing thymocytes. The incidence of double-positive cells was highest at 44 days (compared with 30 days and 80 days) after injection of CB cells. This suggested that a minimum time was required to achieve optimal proliferation of cells in the thy/liv organ but that, at later times, all of the early cells had matured. Thus, the population used for engraftment contained early cells but not self-renewing cells. The double-positive cells matured rapidly into single-positive cells (either CD4+ or CD8+) when placed in ex vivo culture. Marked cells (neo+) could readily be detected in the thy/liv-derived cells. The cells transduced with DT-A showed long-term protection in ex vivo culture against HIV T lymphotropic isolate NL4-3. This study shows that DT-A-transduced cells had no apparent disadvantage in engraftment of the thy/liv organ and did not have any toxic effects in vivo. Such cells were protected against HIV infection even when challenged more than 2 months after transduction and after a 44-day engraftment period in the thy/liv mice. These data support the feasibility of toxin gene therapy as a strategy for HIV infection.

Lipid- and adenoviral-mediated gene transfer into AIDS-Kaposi's sarcoma cell lines

Kaposi's sarcoma (KS) is the most frequent malignancy occurring in HIV-positive individuals. AIDS-KS is a more aggressive disease than the classical form, frequently having a rapid clinical course with numerous serious complications. Current systemic treatments for KS, such as chemotherapy and the administration of biological modifiers, are complicated by both the drug resistance of the tumor and the dose-limiting toxicity of the reagents. The relative accessibility of many KS lesions makes the disease a particularly attractive candidate for in vivo gene therapy protocols. In this regard, we are interested in delivering conditionally toxic suicide and/or antiangiogenic vectors to accomplish targeted cell death selectively in AIDS-KS cells. To this end, we examined both cationic lipid- and adenoviral-mediated DNA transfection methods. Using the firefly luciferase reporter gene, we optimized numerous variables known to be important in lipid-mediated DNA transfection, including lipid formulation, the amount of lipid and DNA, lipid/DNA ratio, and cell concentration. Under optimal transfection conditions, approximately 5-25% of KS cells expressed the introduced DNA sequences. Adenoviral-mediated DNA delivery was more efficient than lipid delivery in 4 of 5 primary KS cell lines. Two of the lines (RW248 and RW376) were transduced by adenovirus at frequencies approaching 100%; two cell lines (CVU-1 and RW80) gave efficiencies of 20-35%. Two immortalized KS cell lines (KS Y-1 and KS SLK) were poorly infected, giving a transduction efficiency of <5%. These findings demonstrate that gene transfer into AIDS-KS cells is feasible, and suggest that vector strategies may be permissive for translating gene therapy approaches for the disease.

Comparison of retroviral-mediated gene transfer into cultured human CD34+ hematopoietic progenitor cells derived from peripheral blood, bone marrow, and fetal umbilical cord blood

Genetic alteration of stem cells ex vivo followed by bone marrow transplantation could potentially be used in the treatment of numerous diseases and malignancies. However, there are many unanswered questions as to the best source of hematopoietic cells for long-term reengraftment and the most effective way to introduce foreign genes into this target cell. We have compared retroviral-mediated gene transfer into CD34+-enriched cells derived from peripheral blood (PB), bone marrow (BM), or fetal umbilical cord blood (CB). Cells from all three sources that had been expanded ex vivo in the presence of stem cell factor (SCF), interleukin-3 (IL-3), IL-6, and granulocyte colony-stimulating factor (G-CSF) showed transduction efficiencies ranging from 5-45%, as measured by acquisition of G418 resistance. The average efficiencies of gene transfer from multiple experiments for PB, BM, and CB were not statistically different. To determine the effect of ex vivo expansion on gene transfer into CB CD34+ cells, we compared the transduction efficiencies of cells exposed to virus immediately after harvest and CD34 selection or after 6 days of culture CD34+ CB cells were more effectively transduced after expansion in culture, showing gene transfer efficiencies 3- to 5-fold higher on day 6 compared with day 0. Last, we examined retroviral transduction via spinoculation of CB CD34+ cells and found it to be approximately as effective as our standard transduction with no significant loss of cell viability as measured by colony formation in semi-solid medium.

Current challenges of gene therapy for prostate cancer

Gene therapy for prostate cancer faces hurdles similar to those being encountered for other cancers and nonmalignant processes. The greatest obstacle is the identification of efficient delivery systems, since numerous animal models and cell culture systems have shown potential efficacy when most cells express the introduced genetic material. Early prostate cancers are easily accessible to gene vector introduction, and the predictable metastatic patterns of this cancer may offer additional advantages for gene therapy. This article reviews gene vectors and gene products, as well as ongoing trials of gene therapy that have recently begun in prostate cancer.

Cationic liposome-mediated expression of HIV-regulated luciferase and diphtheria toxin a genes in HeLa cells infected with or expressing HIV

HIV-regulated expression of the diphtheria toxin A fragment gene (HIV-DT-A) is a potential gene therapy approach to AIDS. Since cationic liposomes are safe and non-immunogenic for in vivo gene delivery, we examined whether LipofectAMINE or DMRIE reagent could mediate the transfection of HIV-DT-A (pTHA43) or the HIV-regulated luciferase gene (pLUCA43) into HIV-infected or uninfected HeLa cells. pLUCA43 was expressed at a 10(3)-fold higher level in HeLa/LAV cells than in uninfected HeLa cells, while the extent of expression of RSV-regulated luciferase was the same in both cell lines. Co-transfection of HeLa cells with pTHA43 and the proviral HIV clone, HXB deltaBgl, resulted in complete inhibition of virus production. In contrast, the delivery of HIV-DT-A to chronically infected HeLa/LAV or HeLa/IIIB cells, or to HeLa CD4+ cells before infection, did not have a specific effect on virus production, since treatment of cells with control plasmids also reduced virus production. This reduction could be ascribed to cytotoxicity of the reagents. The efficiency of transfection, as measured by the percentage of cells expressing beta-gal, was approximately 5%. Thus, cationic liposome-mediated transfection was too inefficient to inhibit virus production when the DT-A was delivered by cationic liposomes to chronically- or de novo- infected cells. However, when both the virus and DT-A genes were delivered into the same cells by cationic liposomes, DT-A was very effective at inhibiting virus production. Our results indicate that the successful use of cationic liposomes for gene therapy will require the improvement of their transfection efficiency.

Improved production of recombinant AAV by transient transfection of NB324K cells using electroporation

Adeno-associated virus (AAV) is useful as an integrating vector for gene transfer. AAV recombinants are generally produced by transient co-transfection methods since it has proven difficult to generate stable packaging cell lines. Acceptable titers of transducing recombinants should be obtainable by optimizing conditions for transient co-transfection. Here, using a luciferase reporter derivative of the AAV infectious plasmid psub201, we show that substantially higher yields of transducing virus can be obtained using electroporation, rather than calcium phosphate transfection. Furthermore, we observed that electroporation of NB324K cells (an SV40-transformed human cell line) with the helper plasmid, pAAV/Ad, with concomitant adenovirus dl309 infection, gave yields of luciferase transducing recombinant AAV equal or superior to those obtained from the more commonly employed 293 cells. NB324K cells are easier to manipulate and show increased cell-association of the recombinant virus (facilitating its concentration and purification). We also adapted an in situ infected cell hybridization procedure, using a digoxigenin labeled probe, as a general method for determining infectious titer. Titers thus estimated were similar for luciferase-transducing and for alkaline phosphatase-transducing AAV vectors: the estimated titer of the latter agreed with that determined by in situ expression of alkaline phosphatase. We also describe a multiple cloning site derivative of psub201 which should facilitate generation of further AAV recombinants.

Optimization of gene transfer using cationic lipids in cell lines and primary human CD4+ and CD34+ hematopoietic cells

Cationic lipids offer several advantages for gene delivery, both in vitro and in vivo. However, high-efficiency gene transfer has been demonstrated only for limited cell types. Here, we examine the level of expression of a luciferase reporter gene, delivered using cationic lipids, in both cell lines and primary human cells including peripheral blood mononuclear cells and CD34(+)-enriched hematopoietic cells. Variables shown to affect the efficiency of gene expression included the type of lipid, the amounts of DNA and lipid, the day of assay following transfection, the media used for lipid:DNA complex formation, the cell number, the promoter driving expression of the reporter gene and the physiological state of the cells (e.g., whether or not cells were differentiated). The maximal luciferase expression observed with the primary cells was one to two orders of magnitude lower than that seen in cell lines. Further studies, possibly involving altering the growth conditions for the cells, or using episomal vectors that will allow extrachromosomal maintenance of the DNA, are required to improve the level of transgene expression in the primary human cell types used here.

HIV-regulated diphtheria toxin A chain gene confers long-term protection against HIV type 1 infection in the human promonocytic cell line U937

Gene therapy approaches have recently been investigated for the treatment of acquired immunodeficiency syndrome (AIDS), both in preclinical and clinical studies, because more traditional antiviral agents have proven to be of limited effectiveness. We have previously shown that long-term protection against both laboratory and clinical isolates of human immunodeficiency virus type 1 (HIV-1) was conferred by HIV-regulated diphtheria toxin A (DT-A) chain in a human T cell line. Because the monocyte/macrophage cell is an important reservoir for HIV-1 in infected individuals, we sought here to determine whether HIV-regulated DT-A would also be effective in the promonocytic cell line U937. We report here that long-term protection, conferred by HIV-regulated DT-A, was observed in U937 cells, but that protection was dependent on the stock of HIV IIIB used for challenge. HIV production was measured by p24 assays, polymerase chain reaction (PCR) for HIV vif, gag, and reverse transcriptase (RT) sequences, and cocultivation with peripheral blood mononuclear cells (PBMCs). Complete protection was seen in DT-A-transduced cells with a stock of IIIB propagated on H9 cells and titered on peripheral blood mononuclear cells (PBMCs), while protection in these same cells with a second stock of IIIB, propagated and titered on H9 cells, was only partial and dose dependent.

Efficient foreign gene expression in Epstein-Barr virus-transformed human B-cells

Epstein-Barr virus (EBV) is a herpesvirus that transforms B-cells (B-LCL) and has undergone intense scrutiny owing to its association with Burkitt's lymphoma, nasopharyngeal carcinoma, and immunoblastic lymphomas. B-LCL have also proven useful in the study of human immunology. We describe a novel system for inducing efficient foreign gene expression in B-LCL using biotinylated adenovirus as an endosome-disrupting agent. Plasmid DNA is coupled to the exterior of viral particles by streptavidin-polylysine chimeric proteins. Up to 67% of B-LCL may be induced to express foreign genes in vitro in transient expression systems, and gene expression lasts for at least 17 days. We have expressed firefly luciferase, beta-galactosidase (beta-gal), chloramphenicol acetyltransferase, HIV gag, and env genes, as well as infectious HIV, and the EBV-specific BZLF gene in B-LCL with this system. In vivo delivery of a beta-gal reporter gene to B-LCL was documented in a SCID mouse model. Potential applications include study of genetic regulation of EBV infection and transformation events, study of potential gene therapies for EBV-related B-cell tumors, and production of antigen-presenting cells for use in immunologic assays. Because of the high percentage of cells transformed and the length of foreign gene expression, the possibility of examining foreign gene expression in transient assays, without selection for clonal populations, exists.

Long-term inhibition of clinical and laboratory human immunodeficiency virus strains in human T-cell lines containing an HIV-regulated diphtheria toxin A chain gene

The human immunodeficiency virus (HIV) causes persistent infection of T cells. Chemotherapy for infection in humans may slow HIV-related disease progression, but it does not eradicate virus. Thus, other treatment modalities are warranted. We have previously demonstrated that the human T cell line H9, ordinarily permissive for HIV infection, may be protected against infection with the LAI strain of HIV by intracellular immunization with the gene encoding diphtheria toxin A chain (DT-A) under the control of HIV Tat and Rev. Cloned cells were protected for up to 6 days in vitro. We now report protection against the LAI laboratory isolate for up to 59 days, and against clinical HIV strains of differing phenotypic properties and cell tropisms for up to 59 days. In some cases, protection was complete in that no residual HIV was detected by HIV p24 antigen production, co-culture with parental H9 cells, or the polymerase chain reaction (PCR). CD4+ surface expression of DT-A transduced cloned H9 cells was similar to parental H9 in most cases. These results suggest that toxin gene therapy for HIV infection may ultimately be feasible.

Effects of enhancer mutations on the expression of human immunodeficiency virus 1-regulated luciferase and diphtheria toxin A chain genes in transfected cells

This study explores human immunodeficiency virus 1 (HIV-1)-regulated diphtheria toxin A (DT-A) gene expression as a means of eradicating HIV-infected cells. Previously, we constructed luciferase and DT-A plasmids, containing cis-acting Tat and Rev responsive elements, which showed low basal expression and required both Tat and Rev for maximal expression. Cell lines which had stably integrated the DT-A constructs were resistant to HIV production. To reduce toxicity due to basal expression, this study investigates the effect of mutations in the HIV enhancer on expression of luciferase and DT-A plasmids. Some mutations were found to substantially reduce basal expression while still allowing for trans-activation. Such mutations, in combination with attenuated versions of DT-A, may make regulated toxin gene expression feasible as a therapy for AIDS.

Inhibition of human immunodeficiency virus-1 production resulting from transduction with a retrovirus containing an HIV-regulated diphtheria toxin A chain gene

Expression of a gene encoding the diphtheria toxin A (DT-A) chain, under the control of human immunodeficiency virus-1 (HIV-1) proteins Tat and Rev, has previously been shown to confer on cells an impaired ability to produce HIV. That work was done in HeLa cell lines that had stably integrated the regulated DT-A gene in a plasmid context. To increase the efficiency with which the HIV-regulated DT-A gene could be introduced into cells, we studied a recombinant, amphotropic murine leukemia virus containing the HIV-regulated DT-A transcription unit. Here we demonstrate that such recombinant retroviruses can be packaged, for both wild-type DT-A and an attenuated version, tox 176. In transient transfection assays, the proviral constructs exhibited similar basal and trans-activated levels of DT-A expression to the parental plasmids. Transduced H9 cells expressed the integrated DT-A gene upon transfection with plasmids encoding Tat and Rev, as assayed by decreased expression of a cotransfected luciferase reporter gene. Furthermore, the transduced H9 cells were substantially impaired in their ability to produce HIV, as demonstrated by p24 assays of culture supernatants following either transfection with an HIV proviral clone or infection with HIV-IIIB. These data demonstrate that basal expression of the regulated DT-A gene has been reduced to a tolerable level, both in packaging cells and transduced H9 cells. The use of HIV-regulated retroviruses encoding the highly lethal DT-A product may eventually be applicable as a gene therapy approach for the acquired immunodeficiency syndrome (AIDS).

Inhibition of HIV production in cells containing an integrated, HIV-regulated diphtheria toxin A chain gene

Construction of a DNA plasmid that expresses a diphtheria toxin A chain (DT-A) gene under control of human immunodeficiency virus (HIV-1) proteins Tat and Rev has been described. Here the generation of HeLa cell clones containing integrated, HIV-regulated DT-A sequences is reported. Five such clones were identified by their decreased expression of a luciferase reporter gene transiently cotransfected with Tat- and Rev-encoding plasmids. The decreased luciferase expression most probably was due to activation of the integrated DT-A gene because higher luciferase activity could be restored by introducing either DT antitoxin or a gene encoding a mutant, DT-resistant elongation factor 2 (the intracellular target for DT-A). Analysis by polymerase chain reaction (PCR) indicated that all clones expressed DT-A encoding RNA. The clones were then transfected with an HIV proviral clone and were tested for HIV production; all five clones demonstrated substantially impaired HIV production compared with parental HeLa cells, as shown by p24 assays of culture supernatants. Our success in generating these cell lines indicates that extremely low basal expression has been achieved in view of the high cellular lethality of DT-A. HIV-regulated expression of DT-A may be applicable as a gene therapy approach for the acquired immune deficiency syndrome (AIDS), to bring about selective suicide of HIV-infected cells before production of viral progeny.

The Winchester experience with the TDS hospital information system

The Royal Hampshire County Hospital is a pilot site for the Resource Management Initiative. It is also the pilot site within the Wessex Region for the Hospital Information System (HIS). We have pursued an ambitious, integrated information system strategy within the hospital. This has been planned and most of it implemented within a short timescale. Although some of the remaining difficulties are technical, the greatest challenges relate to people, their reactions to the introduction of new technology and the need to acquire new skills. The training and development of staff become critical. The importance of an effective management structure with major medical and nursing involvement has been, and will remain, crucial to our continued progress.

Activation of a diphtheria toxin A gene by expression of human immunodeficiency virus-1 Tat and Rev proteins in transfected cells

Expression of a gene encoding the diphtheria toxin A (DT-A) fragment, controlled by tissue specific regulatory elements, has previously been used to kill selected cell populations. Here, we have examined the feasibility of controlling DT-A expression using regulatory systems from the human immunodeficiency virus (HIV-1) genome. Plasmids were constructed which express either DT-A or, as a model system, the luciferase (luc) reporter gene, under control of HIV-1 long terminal repeat (LTR) sequences (-167 to +80). While trans-activation by expression of the viral protein Tat was demonstrated, significant basal expression was observed. To reduce basal expression, cis-acting negative regulatory elements from the env region of the HIV-1 genome were inserted in the 3' untranslated region of both the luc and DT-A constructs. This dramatically reduced basal expression from the HIV LTR, and now both viral regulatory proteins Tat and Rev were required for maximal trans-activation. Such regulation of DT-A expression might be therapeutically applied to selectively kill HIV-infected cells in acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC).

Should urologists wear spectacles for transurethral resection of the prostate?

Contamination of the eyes by irrigation fluid during transurethral resection (TUR) of the prostate was assessed by measuring droplet splashes on to spectacles worn by 2 surgeons. During 30 consecutive operations, droplet splash contamination occurred during every procedure. The number of splashes increased with time. The use of spectacles during TUR will reduce the risks of eye contamination from droplet splashes and therefore the possibility of transmission of the human immunodeficiency virus from infected patients.

Molecular analysis of N6-methyladenine patterns in Tetrahymena thermophila nuclear DNA

We have cloned two DNA fragments containing 5'-GATC-3' sites at which the adenine is methylated in the macronucleus of the ciliate Tetrahymena thermophila. Using these cloned fragments as molecular probes, we analyzed the maintenance of methylation patterns at two partially and two uniformly methylated sites. Our results suggest that a semiconservative copying model for maintenance of methylation is not sufficient to account for the methylation patterns we found during somatic growth of Tetrahymena. Although we detected hemimethylated molecules in macronuclear DNA, they were present in both replicating and nonreplicating DNA. In addition, we observed that a complex methylation pattern including partially methylated sites was maintained during vegetative growth. This required the activity of a methylase capable of recognizing and modifying sites specified by something other than hemimethylation. We suggest that a eucaryotic maintenance methylase may be capable of discriminating between potential methylation sites to ensure the inheritance of methylation patterns.

A DNA cassette containing a trimerized SV40 polyadenylation signal which efficiently blocks spurious plasmid-initiated transcription

A head-to-tail trimer of the SV40 Bcl I-Bam H1 DNA fragment, specifying polyadenylation of RNA transcripts, was cloned as a cassette flanked by multiple restriction sites. Insertion of the trimer into several expression vectors efficiently prevented spurious expression of reporter genes resulting from transcriptional initiation in prokaryotic plasmid sequences in transfected mammalian cells.

Methylation of replicating and nonreplicating DNA in the ciliate Tetrahymena thermophila

Methylation of adenine in replicating and nonreplicating DNA of the ciliate Tetrahymena thermophila was examined. In growing cells, 87% of the methylation occurred on the newly replicated daughter strand, but methylation was also detectable on the parental strand. Methylation of nonreplicating DNA from starved cells was demonstrated.

Chromosomal location of human genes encoding major heat-shock protein HSP70

The HSP70 family of heat-shock proteins constitutes the major proteins synthesized in response to elevated temperatures and other forms of stress. In eukaryotes members of the HSP70 family also include a protein similar if not identical to bovine brain uncoating ATPase and glucose-regulated proteins. An intriguing relation has been established between expression of heat-shock proteins and transformation in mammalian cells. Elevated levels of HSP70 are found in some transformed cell lines, and viral and cellular gene products that are capable of transforming cells in vitro can also stimulate transcription of HSP70 genes. To determine the organization of this complex multigene family in the human genome, we used complementary approaches: Southern analysis and protein gels of Chinese hamster-human somatic cell hybrids, and in situ hybridization to human chromosomes. We demonstrate that functional genes encoding HSP70 proteins map to human chromosomes 6, 14, 21, and at least one other chromosome.

Site-specific methylation of adenine in the nuclear genome of a eucaryote, Tetrahymena thermophila

DNA in the polyploid macronucleus of the ciliated protozoan Tetrahymena thermophila contains the modified base N6-methyladenine. We identified two GATC sites which are methylated in most or all of the 45 copies of the macronuclear genome. One site is 2 kilobases 5' to the histone H4-I gene, and the other is 5 kilobases 3' to the 73-kilodalton heat shock protein gene. These sites are de novo methylated between 10 and 16 h after initiation of conjugation, during macronuclear anlage development. The methylation states of these two GATC sites and four other unmethylated GATC sites do not change in the DNA of cells cultured under conditions which change the activity of the genes, including logarithmic growth, starvation, and heat shock.

DNA synthesis, methylation and degradation during conjugation in Tetrahymena thermophila

We have investigated the timing of DNA synthesis, methylation and degradation during macronuclear development in the ciliate, Tetrahymena thermophila. DNA synthesis was first detected in the anlagen early in macronuclear development, but the majority of DNA synthesis occurred later, after pair separation. Anlagen DNA was first detectably methylated at GATC sites 3-5 hours after its synthesis. Once initiated, de novo methylation was rapid and complete, occurring between 13.5 and 15 hours of conjugation. The level of methylation of GATC sites was constant throughout the remainder of conjugation, and was similar to that in mock-conjugated cells. Degradation of DNA in the old macronucleus and DNA synthesis in the anlagen began at about the same time. Upon pair separation, less than 20% of old macronuclear DNA remained. A small percentage of nucleotides prelabeled prior to conjugation were recycled in the developing anlagen.

Asepsis and out-patient cystoscopy

Cystoscopy was performed on a control group of 74 patients under full sterile precautions and on a study group of 83 patients under aseptic conditions, which required fewer materials. The incidence of urinary infections in the two groups was 4 and 6% respectively; this difference is not statistically significant. Rigors were rare in both groups (1%). The financial savings achieved by using an aseptic technique for out-patient cystoscopy are discussed.

A phase II study of intravesical mitomycin C in the treatment of superficial bladder cancer

Twenty-three patients with histologically proven superficial bladder cancer (Tis, Ta, T1) were treated with intravesical instillations of Mitomycin C at a dose of 20 mg in 20 ml of water 3 times weekly for 21 instillations. Seventeen patients (77%) showed complete disappearance of all known disease and a further 4 showed partial responses. In 8 patients toxic effects developed (thrombocytopaenia 1, chemical cystitis 2, skin rash 3, urinary tract infection 2). All resolved rapidly on stopping the treatment but were severe enough in 5 patients to prevent them from receiving a full course of treatment.

The prognosis of prostatic cancer in the younger man

The effect of age on the prognosis of prostatic cancer is uncertain. Younger patients are commonly assumed to have a worse prognosis. To investigate this impression, survival rates were calculated for two groups of patients with histologically proven prostatic cancer aged under 60 years (46 patients) and 65 to 74 years (193 patients). Age-corrected actuarial survival curves for the two groups were not significantly different when tested by the log rank method. Similar curves constructed for well and poorly differentiated tumours, the presence of metastases and different treatment groups were also not significantly different. The survival of younger patients with prostatic cancer is not significantly worse than that of older patients, nor is it better.

Transitional cell carcinoma in a congenital ureteral diverticulum

Congenital diverticula of the ureter are uncommon. They are liable to the complications of infection and stone formation but tumor has not been reported previously. A case of transitional cell carcinoma in a diverticulum of the lower ureter is described.

The management of pyonephrosis

The treatment of 63 cases of pyonephrosis is described. The primary procedure in 39 patients (62%) was nephrectomy. A drainage procedure, usually nephrostomy, was performed in the remainder and in 10 cases an obstructing stone was removed. In 13 cases (21%) a useful functioning kidney resulted from conservative surgery. The indications for the different treatments are discussed.

12-year experience using the dormia basket for the extraction of ureteric stones

201 patients underwent attempted extraction of a ureteric stone using the Dormia basket. This was successful in 52% of the cases. Failure was due to the inability to pass the catheter (13%) or failure to catch the stone (30%). Operative complications were seen in a further seven cases (3%) and the overall complication rate was 11% (23 cases). An experienced operator had a slightly improved chance of extracting a stone successfully when compared with a trainee, but this was not significant. In approximately half the cases in which the stone was not extracted, it passed spontaneously. The remainder required a further procedure to remove the stone.

Observations on the role of esophagogastrostomy in infancy and childhood with particular reference to the long-term results and operative mortality

Esophagogastrostomy is a satisfactory method of restoring continuity of the esophagus with minimal long-term effects on growth and development. Anemia or reflux oesophagitis is not a complication of the operation provided the anastomosis is high in the thoracic cage, i.e., above the level of the aortic arch. Postural gastritis secondary to regurgitation of bile was not seen in our patients. The mortality of the operation is high (33%) but this is due to the small number of patients in whom it is indicated. This contrasts markedly with the results in adults where the mortality in large series has fallen to low levels (13%). Thus, esophagogastrostomy should retain a place in selected patients for the primary treatment of esophageal atresia and the high esophageal stricture.