Transurethral bladder catheterization of male rhesus macaques: a refinement of approach

BACKGROUND

Successful transurethral bladder catheterization in male non-human primates can be challenging. An optimized approach for consistent and reproducible catheterization using a refined technique is described.

METHODS

Under sedated and non-sedated conditions, transurethral bladder catheterization was performed on 25 male rhesus macaques of varying ages and body weights over time. A refined technique ensuring optimal lubrication of the urethral canal prior to catheter insertion was utilized along with various single and multiple lumen catheters.

RESULTS

All animals were successfully catheterized. Sixty-five catheterization sessions were conducted with a high overall success rate (100%). The incidence of catheter (10%) and post-catheterization (2%) complications was low.

CONCLUSIONS

The urinary bladder of male rhesus can be reliably and reproducibly catheterized with minimal complication using this approach. Successful catheterization was facilitated by thorough urethral lubrication and using suitable catheters. In addition, this approach may be performed without sedation on thoroughly conditioned animals.

Alcohol use and HIV sexual risk among MSM in Chennai, India

Men who have sex with men (MSM) in India are a core risk group for HIV. Heavy alcohol consumption is associated with increased sexual risk-taking behaviours in many cultures, in particular among MSM. However, no studies to date have explored alcohol use and HIV risk among MSM in India. MSM in Chennai, India (n = 210) completed an interviewer-administered behavioural and psychosocial assessment. Bivariate and multivariable logistic regression procedures examined behavioural and demographic associations with weekly alcohol consumption. Twenty-eight percent of the sample (n = 58) reported using alcohol at least weekly to the point of being buzzed/intoxicated, which was associated with older age, being married to a woman, being panthi (masculine appearing, predominantly insertive partners) versus kothi (feminine acting/appearing and predominantly receptive partners), weekly tobacco use, unprotected anal sex and unprotected vaginal sex in the three months prior to study enrollment (all P < 0.05). In a multivariable model, unprotected vaginal sex in the previous three months and being married to a women were unique variables associated with weekly alcohol use (all P < 0.01). Further investigation of alcohol use within the context of sexual risk taking is warranted among Indian MSM. Panthis and MSM who are married to women may be particularly likely to benefit from interventions to decrease alcohol intake and concurrent unsafe sex.

Comparative analysis of the effects of antimuscarinic agents on bladder functions in both nonhuman primates and rodents

Both the physiological role of muscarinic receptors for bladder function and the therapeutic efficacy of antimuscarinic agents for overactive bladder syndrome are well documented. We investigated the effect of antimuscarinic agents with different subtype selectivity on urodynamic parameters in nonhuman primates and rodents and compared plasma levels of these agents between species. Anesthetized rhesus monkeys were transurethrally catheterized, and the bladder was infused with saline. Urodynamic parameters were measured before and after intravenous drug administration. Tolterodine (nonselective) and oxybutynin (moderately M(3)-selective) increased bladder capacity at lower doses than those required to decrease micturition pressure. However, higher doses of darifenacin (M(3)-selective) were needed to increase the bladder capacity than those needed to decrease the micturition pressure. In rats, tolterodine had no effect on the bladder capacity but decreased the micturition pressure at all of the doses administered. Oxybutynin also decreased micturition pressure and increased bladder capacity at the highest dose. Plasma levels of these drugs overlap in both species. These results suggest that, in addition to the M(3) receptor, other muscarinic receptor subtypes contribute to regulate bladder storage function in nonhuman primates, since less subtype-selective tolterodine and oxybutynin showed higher specificity to the bladder capacity effect than the effect on micturition pressure compared with M(3)-selective darifenacin. In addition, the role of muscarinic receptors in bladder storage function varies between primates and rodents. Compared with rodents, muscarinic receptors may play a more active role during the storage phase to regulate the functional bladder capacity in primates.

Evaluation of combined (177)Lu-DOTA-8-AOC-BBN (7-14)NH(2) GRP receptor-targeted radiotherapy and chemotherapy in PC-3 human prostate tumor cell xenografted SCID mice

The focus of this study was to evaluate the therapeutic benefit of combined gastrin-releasing peptide (GRP) receptor-targeted radiotherapy (TRT) with chemotherapy, using the PC-3 xenograft severe combined immunodeficiency (SCID) mouse model. (177)Lu-DOTA-8-AOC-BBN(7-14)NH(2) is a radiotherapeutic peptide that specifically targets the gastrin-releasing peptide receptor overexpressed on primary and metastatic prostate cancer. The chemotherapeutic agents, docetaxel and estramustine, were administered as single agents or in combination with the receptor-targeted radiotherapeutic agent. Combination receptor TRT/chemotherapy studies were begun 21 days postxenografting and were conducted as multiple-dose trials. The GRP receptor TRT agent was administered every 14 days, and single and combination chemotherapy dose regimens were given weekly. Tumor size, body weight, and body condition score were evaluated twice-weekly and a hematology profile once-weekly. Therapy study tumor volumes were evaluated by way of a repeated measures analysis of variance (ANOVA). Tumor volume measurements at 12 days postdose administration demonstrated a statistically significant (two-tailed P-value <0.05) tumor growth suppression in all experimental groups receiving GRP receptor-targeted radiotherapy, when compared to the control group. The two combined GRP receptor TRT/chemotherapy treatment groups demonstrated the greatest tumor growth suppression of all treatment groups. In comparing the two combined GRP receptor TRT/chemotherapy groups to the GRP receptor TRT alone group, a statistically significant difference was demonstrated for the combined groups by day 30, postdose administration. These data demonstrate that GRP receptor-targeted radiation therapy, using (177)Lu-DOTA-8-AOC-BBN(7-14)NH(2), used either alone or in combination with conventional chemotherapy, can suppress the growth of androgen- independent prostate cancer (AIPC).

Premature termination codon in the aggrecan gene of nanomelia and its influence on mRNA transport and stability

AIM

To analyze the influence of the premature termination codon on mRNA transport and stability

METHODS

Chondrocyte mRNA was isolated from homozygous and heterozygous nanomelic 17-days old embryos and examined by RT-PCR analysis. To analyze aggrecan mRNA stability, mRNA synthesis was inhibited with DRB [5,6 dichloro-1-(-D-ribofuranosyl benzimidazole)], a specific inhibitor of RNA polymerase II. Visualization of the aggrecan alleles was performed by in situ hybridization.

RESULTS

The level of mutant aggrecan mRNA within the nucleus was equal to that of the control, but no mutant mRNA was observed in the cytoplasm. RT-PCR revealed that the mutant transcript was only detectable in the nucleus, compared with house-keeping glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene or collagen type II. A restriction site induced by premature termination codon TAA allowed the distinction of normal and mutant transcripts in chondrocytes derived from embryos heterozygous for the nanomelic mutation. After the treatment with DRB, identical decay rates were demonstrated for both transcripts within the heterozygous nucleus. In situ hybridization showed no abnormal mRNA accumulation.

CONCLUSION

This is the first evidence suggesting that the transcript of the mRNA with the premature termination codon within an exon does exit the nucleus.

Nonrandom gene organization: structural arrangements of specific pre-mRNA transcription and splicing with SC-35 domains

This work demonstrates a highly nonrandom distribution of specific genes relative to nuclear domains enriched in splicing factors and poly(A)+ RNA, and provides evidence for the direct involvement of these in pre-mRNA metabolism. As investigated in hundreds of diploid fibroblasts, human collagen I alpha 1 and beta-actin DNA/RNA showed a very high degree of spatial association with SC-35 domains, whereas three nontranscribed genes, myosin heavy chain, neurotensin, and albumin, showed no such preferential association. Collagen I alpha 1 RNA accumulates within the more central region of the domain, whereas beta-actin RNA localizes at the periphery. A novel approach revealed that collagen RNA tracks are polarized, with the entire gene at one end, on the edge of the domain, and the RNA extending into the domain. Intron 26 is spliced within the RNA track at the domain periphery. Transcriptional inhibition studies show both the structure of the domain and the gene's relationship to it are not dependent upon the continued presence of accumulated collagen RNA, and that domains remaining after inhibition are not just storage sites. Results support a model reconciling light and electron microscopic observations which proposes that transcription of some specific genes occurs at the border of domains, which may also function in the assembly or distribution of RNA metabolic components. In contrast to the apparently random dispersal of total undefined hnRNA synthesis through interdomain space, transcription and splicing for some genes occurs preferentially at specific sites, and a high degree of individual pre-mRNA metabolism is compartmentalized with discrete SC-35 domains.

U2 and U1 snRNA gene loci associate with coiled bodies

The coiled bodies are nuclear structures rich in a variety of nuclear and nucleolar components including snRNAs. We have investigated the possibility that coiled bodies may associate with snRNA genes and report here that there is a high degree of association between U2 and U1 genes with a subset of coiled bodies. As investigated in human HeLa cells grown in monolayer culture, about 75% of nuclei had at least one U2 gene associated with a coiled body, and 45% had at least one U1 locus associated. In another suspension-grown HeLa cell strain, 92% of cells showed associated of one or more U2 genes with coiled bodies. In contrast to the U2 and U1 gene associations, a locus closely linked to the U2 gene cluster appeared associated with a coiled body only in 10% of cells. Associated snRNA gene signals were repeatedly positioned at the edge of the coiled body. Thus, this associated was highly nonrandom and spatially precise. Our analysis revealed a much higher frequency of association for closely spaced "doublet" U2 gene signals, with over 80% of paired signals associated as opposed to 35% for single U2 signals. This finding, coupled with the fact that not all genes were associated in all cells, suggested the possibility of a cell-cycle-dependent, possibly S-phase, association. However, an analysis of S- and non-S-phase cells using BrdU incorporation or cell synchronization did not indicate an increased level of association in S-phase. These and other results suggested that a substantial fraction of paired U2 signals represented association of U2 genes on homologous chromosomes rather than only replicated DNA. Furthermore, triple label analysis showed that in a significant fraction of cells U1 and U2 genes were both associated with the same coiled body. U1 and U2 genes were closely paired in approximately 20% of cells, over 60% of which were associated with a readily identifiable coiled body. This finding raises the possibility that multiple genes of a particular class may be in association with each coiled body. Thus, the coiled body may be a dynamic structure which transiently interacts with or is formed by one or more specific genetic loci, possibly carrying out some function related to their expression.

Isolation and mapping of human T-cell protein tyrosine phosphatase sequences: localization of genes and pseudogenes discriminated using fluorescence hybridization with genomic versus cDNA probes

This work reports the isolation, partial characterization, and chromosomal mapping of several human T-cell protein tyrosine phosphatase (PTPase) sequences and provides a direct comparison of the specificity of cDNA versus genomic probes in discriminating the location of genes versus pseudogenes by fluorescence in situ hybridization. In initial attempts to map the T-cell (TC) PTP gene using a 2-kb cDNA, several labeled sites were noted, raising the possibility of multiple related sequences within the genome. To address this, four genomic clones were obtained with homology to the TC PTP cDNA and characterized for their primary structure and their position within the human genome. Based on the presence or absence of an open reading frame and the intron/exon structure, two of these clones were found to be overlapping sequences encoding the true TC PTP gene and two were highly related but distinct processed pseudogenes. The TC PTP gene (gene symbol PTPN2) encoded by clones L17-2 and L5-1 localized to chromosome 18p11.2-p11.3, whereas pseudogenes encoded by clone L17-1, entitled TCPS1 (gene symbol PTPN2P1), and clone L18, entitled TCPS13 (gene symbol PTPN2P2), mapped to chromosomes 1q22-q24 and 13q12-q13, respectively. A direct comparison of the specificity of genomic and cDNA probes demonstrated that under identical conditions the genomic probes (containing both exon and intron sequences) readily identified a single specific site of hybridization, whereas the cDNA identified sites of both the gene and its pseudogenes. While providing mapping and sequencing information on the TC PTPase sequences, this work illustrates a strategy for addressing a recurrent problem in gene mapping studies where highly related sequences exist within the genome.

Higher level organization of individual gene transcription and RNA splicing

Visualization of fibronectin and neurotensin messenger RNAs within mammalian interphase nuclei was achieved by fluorescence hybridization with genomic, complementary DNA, and intron-specific probes. Unspliced transcripts accumulated in one or two sites per nucleus. Fibronectin RNA frequently accumulated in elongated tracks that overlapped and extended well beyond the site of transcription. Splicing appears to occur directly within this RNA track, as evidenced by an unambiguous spatial separation of intron-containing and spliced transcripts. Excised introns for neurotensin RNA appear free to diffuse. The transcription and processing site of the fibronectin gene localized to the nuclear interior and was associated with larger transcript domains in over 88 percent of the cells. These results support a view of nuclear function closely integrated with structure.

The HIV-1 Rev protein: a model system for coupled RNA transport and translation

The impact of the Rev protein of the human immunodeficiency virus type 1 (HIV-1) on RNA transport, intranuclear RNA distribution, and gene expression was examined for two Rev-dependent expression systems by means of fluorescence in situ hybridization, immunofluorescence, S1 nuclease protection, and functional assays. In the pgTat expression system, which utilizes authentic HIV-1 splice signals, unspliced mRNA remained entrapped in the nucleus in the absence of Rev and was exported to the cytoplasm in its presence, consistent with published findings. In the pSVAR expression system, significant levels of mRNA were found in the nucleus and cytoplasm in both the presence and absence of Rev, but only in the presence of Rev was mRNA translated into protein. The presence of cytoplasmic untranslated mRNA in the absence of Rev was demonstrated by in situ hybridization analysis of individual cells as well as by S1 nuclease analysis of cell populations. The results indicate that Rev has the potential to affect translation as well as transport, suggesting the possibility that cellular mechanisms exist whereby the translational efficiency of an mRNA may be affected by the manner in which it is transported from the nucleus. Fluorescence hybridization also provided high-resolution visualization of the intranuclear distribution of RNAs containing the Rev response element. This demonstrated for both expression systems that mRNA was not highly localized in tracks or around the nucleolus in the presence or absence of Rev, a nucleolar protein, but was more widely distributed throughout the nucleus. In pgTat transfectants, HIV-1 RNA often became localized in 5 to 20 discrete large intranuclear clusters in the presence of Rev, the potential significance of which is discussed.

Localizing DNA and RNA within nuclei and chromosomes by fluorescence in situ hybridization

The enormous potential of in situ hybridization derives from the unique ability of this approach to directly couple cytological and molecular information. In recent years, there has been a surge of success in powerful new applications, resulting from methodologic advances that bring the practical capabilities of this technology closer to its theoretical potential. A major advance has been improvements that enable, with a high degree of reproducibility and efficiency, precise visualization of single sequences within individual metaphase and interphase cells. This has implications for gene mapping, the analysis of nuclear organization, clinical cytogenetics, virology, and studies of gene expression. This article discusses the current state of the art of fluorescence in situ hybridization, with emphasis on applications to human genetics, but including brief discussions on studies of nuclear DNA and RNA organization, and on applications to clinical genetics and virology. Although a review of all of the literature in this field is not possible here, many of the major contributions are summarized along with recent work from our laboratory.

Subcellular localization of low-abundance human immunodeficiency virus nucleic acid sequences visualized by fluorescence in situ hybridization

Detection and subcellular localization of human immunodeficiency virus (HIV) were investigated using sensitive high-resolution in situ hybridization methodology. Lymphocytes infected with HIV in vitro or in vivo were detected by fluorescence after hybridization with either biotin or digoxigenin-labeled probes. At 12 hr after infection in vitro, a single intense signal appeared in the nuclei of individual cells. Later in infection, when cytoplasmic fluorescence became intense, multiple nuclear foci frequently appeared. The nuclear focus consisted of newly synthesized HIV RNA as shown by hybridization in the absence of denaturation and by susceptibility to RNase and actinomycin D. Virus was detected in patient lymphocytes and it was shown that a singular nuclear focus also characterizes cells infected in vivo. The cell line 8E5/LAV containing one defective integrated provirus revealed a similar focus of nuclear RNA, and the single integrated HIV genome was unequivocally visualized on a D-group chromosome. This demonstrates an extremely sensitive single-cell assay for the presence of a single site of HIV transcription in vitro and in vivo and suggests that it derives from one (or very few) viral genomes per cell. In contrast, productive Epstein-Barr virus infection exhibited many foci of nuclear RNA per cell.