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T Horn

Publications and source records attributed to T Horn.

At least 19 recordsLinked to original sources
PubMed1998

Measurements of behavior in the naked mole-rat after intraperitoneal implantation of a radio-telemetry system.

The naked mole-rat (Heterocephalus glaber) is a unique fossorial mammal that is eusocial, object blind, and virtually poikilothermic. This animal is an ideal model to examine questions pertaining to the thermoregulatory aspects of sleep/wake cycles and other circadian events. However, the monitoring of mammalian sleep usually involves implanting permanent electrodes into the skull which are linked to a counter-weighted cable apparatus. This is not a viable option for H. glaber because of the tunneled environments and sensitive social milieu. Instead, to monitor sleep, core temperature, and activity we have utilized intraperitoneal telemetry, a technique that transmits biopotential signals by radio waves. Here we describe the surgical procedure used to implant the device, the anesthesia technique developed, and the social reintroduction method devised for this novel animal model.

Anesthesiology↗
PubMed1998

The influence of the level of lamina propria invasion and the prevalence of p53 nuclear accumulation on survival in stage T1 transitional cell bladder cancer.

PURPOSE: We assessed the influence of the level of lamina propria invasion and the prevalence of p53 nuclear immunoreactivity on the survival of patients with stage T1 transitional cell bladder cancer. MATERIALS AND METHODS: All patients presenting with stage T1 bladder cancer were prospectively and routinely grouped according to the level of lamina propria invasion. Invasion of the tumor stalk was defined as stage T1a, invasion of the lamina propria proper superficial to the level of muscularis mucosa as stage T1b and into or deeper than the muscularis mucosa as stage T1c. The p53 nuclear immunoreactivity was determined with antibody PAB 1801. RESULTS: The study comprised 143 patients including 31 (22%) with stage T1a disease, 60 (42%) with stage T1b and 52 (36%) with stage T1c. Mean patient age was 67 years (range 38 to 92) and mean followup was 4.7 years (range 2.4 to 9.7). Tumor grade related to the depth of lamina propria invasion (p < 0.05) and the prevalence of dysplasia in random mucosal biopsies was higher in stage T1b and T1c tumors than in stage T1a. Of all tumors 42% expressed p53 nuclear reactivity which correlated with tumor grade (p < 0.05). Also the prevalence of nuclear p53 was higher in stages T1b and T1c compared with T1a disease. Of the patients 115 were treated with transurethral resection alone and 28 underwent radical cystectomy. Overall survival was 60.1%. Age was the only independent predictor of survival in patients older than 75 years. For patients up to 75 years old survival related to age, level of lamina propria invasion and presence of p53 nuclear accumulation. For this subpopulation overall survival was 67%, and 79% for stage T1a, 70% for stage T1b and 57% for stage T1c (p < 0.05). Survival was higher in patients with p53 negative (73%) than in those with p53 positive (61%) tumors (p < 0.05). A multivariate analysis of the influence of lamina propria invasion and nuclear p53 status on survival histology was found to be the only independent predictor of survival. CONCLUSIONS: Immediate radical cystectomy should be considered for patients with stage T1c tumors and for some patients with stage T1b disease, particularly those with tumors expressing p53 nuclear reactivity and with dysplasia in the random mucosal biopsies.

Adult↗
PubMed1998

Expression of E-selectin, sialyl Lewis X, and macrophage inflammatory protein-1alpha by colonic epithelial cells in ulcerative colitis.

The pathogenic significance of cell adhesion molecules (CAMs) in ulcerative colitis (UC) is largely unknown. Colonic expression of E-selectin, sialyl Lewis X (sLe(x)), and macrophage inflammatory protein-1x (MIP-1alpha) as well as serum concentrations of E-selectin and MIP-1alpha in UC were studied. Thirty patients with UC, 10 patients with irritable bowel syndrome, and 10 healthy subjects were included. Colonic biopsies were stained immunohistochemically, and blood concentrations were measured with an ELISA technique. Soluble E-selectin did not correlate with diagnosis or disease activity. MIP-1alpha was below the detection limit. Epithelial cells expressed all three molecules, both on surface membranes and intracellularly. sLe(x) staining was weaker (P = 0.0002) and MIP-1alpha staining stronger (P = 0.014) in UC patients than in controls. Leukocyte MIP-alpha staining correlated with diagnosis (P = 0.021), sLe(x) staining (P = 0.023), and colonoscopy (P = 0.018). It is shown that E-selectin, sLe(x), and MIP-1alpha are synthesized and expressed by epithelial cells, indicating that CAMs are not only involved in leukocyte extravasation and migration, but also in the interaction between leukocytes and colonic epithelium. This knowledge might contribute to the development of improved treatments in UC.

Adult↗
PubMed1997

An improved divergent synthesis of comb-type branched oligodeoxyribonucleotides (bDNA) containing multiple secondary sequences.

The divergent synthesis of branched DNA (bDNA) comb structures is described. This new type of bDNA contains one unique oligonucleotide, the primary sequence, covalently attached through a comb-like branch network to many identical copies of a different oligonucleotide, the secondary sequence. The bDNA comb structures were assembled on a solid support and several synthesis parameters were investigated and optimized. The bDNA comb molecules were characterized by polyacrylamide gel electrophoretic methods and by controlled cleavage at periodate-cleavable moieties incorporated during synthesis. The developed chemistry allows synthesis of bDNA comb molecules containing multiple secondary sequences. In the accompanying article we describe the synthesis and characterization of large bDNA combs containing all four deoxynucleotides for use as signal amplifiers in nucleic acid quantification assays.

DNA↗
PubMed1997

Chemical synthesis and characterization of branched oligodeoxyribonucleotides (bDNA) for use as signal amplifiers in nucleic acid quantification assays.

The divergent synthesis of bDNA structures is described. This new type of branched DNA contains one unique oligonucleotide, the primary sequence, covalently attached through a comb-like branching network to many identical copies of a different oligonucleotide, the secondary sequence. The bDNA comb molecules were assembled on a solid support using parameters optimized for bDNA synthesis. The chemistry was used to synthesize bDNA comb molecules containing 15 secondary sequences. The bDNA comb molecules were elaborated by enzymatic ligation into branched amplification multimers, large bDNA molecules (a total of 1068 nt) containing an average of 36 repeated DNA oligomer sequences, each capable of hybridizing specifically to an alkaline phosphatase-labeled oligonucleotide. The bDNA comb molecules were characterized by electrophoretic methods and by controlled cleavage at periodate-cleavable moieties incorporated during synthesis. The branched amplification multimers have been used as signal amplifiers in nucleic acid quantification assays for detection of viral infection. It is possible to detect as few as 50 molecules with bDNA technology.

DNA↗
PubMed1997

[Technetium 99-m sestamibi bone scan in musculo-skeletal neoplasms].

It is often difficult to assess accurately the nature of a skeletal lesion. Problems include differentiating a malignant from a benign bone tumor, as well as determining the cause of a pathologic fracture. Such fractures may occur through osteoporotic bone as well as through neoplasm-affected bone. Thus, development of an imaging modality capable of distinguishing between such lesions is of importance. During 1996, we ran a prospective study in which results of Tc-99m-methyl-diphosphate (MDP) bone scans were compared with those of sestamibi (MIBI) bone scans and with subsequent biopsy and clinical course. The results of the bone scans were assessed by 2 independent "blinded" observers, and the ratios of counts in lesions to those in normal tissue (L/N ratios) were calculated. In cases of malignant (7) and benign (8) tumors, intensity of uptake in MDP scans were not predictive of degree of aggressiveness. On the other hand, MIBI bone scans demonstrated significant difference in intensity of uptake between benign and malignant bone tumors (L/N ratios 2.05 vs 2.75). In 5 of 8 benign lesions the L/N ratio was 1. In the others, increased uptake was minimal. In 2 patients changes in uptake in MIBI bone scan following chemotherapy appeared to be related to the degree of tumor necrosis achieved. While the MIBI bone scan cannot replace tissue biopsy as a definitive diagnostic modality in bone neoplasms, it does appear to allow better preoperative assessment and prognosis.

Adolescent↗
PubMed1997

A branched DNA signal amplification assay for quantification of nucleic acid targets below 100 molecules/ml.

The branched DNA hybridization assay has been improved by the inclusion of the novel nucleotides, isoC and isoG, in the amplification sequences to prevent non-specific hybridization. The novel isoC, isoG-containing amplification sequences have no detectable interaction with any natural DNA sequence. The control of non-specific hybridization in turn permits increased signal amplification. Addition of a 14 site preamplifier was found to increase the signal/noise ratio 8-fold. A set of 74 oligonucleotide probes was designed to the consensus HIV POL sequence. The detection limit of this new HIV branched DNA amplifier assay was approximately 50 molecules/ml. The assay was used to measure viral load in 87 plasma samples of HIV- infected patients on triple drug therapy whose RNA titers were <500 molecules/ml. In all 11 patients viral load eventually declined to below the detection limit with the new assay.

Adenosine↗
PubMed1997

Fixation of human detrusor smooth muscle cells: role of osmolarity and magnesium ions on the ultrastructural morphology.

Magnesium ions added to fixatives for processing to Transmission Electron Microscopy (TEM) have been claimed to cause relaxation of detrusor smooth muscle cells [1]. This should facilitate the morphologic evaluation of the tissue. However, magnesium ions are osmotically active and their addition may cause the fixative to become hypertonic to the tissue. To ascertain whether the presence of magnesium ions causes significant changes compared to those found where the osmolarity is raised without the presence of magnesium, human detrusor specimens were fixed in glutaraldehyde to which increasing amounts of MgCl2 or NaCl were added in different concentrations. With the addition of increasing amounts of MgCl2 and NaCl, the osmolarity of the fixative increased, causing significant changes in the morphology and morphometry of the tissue. The intercellular distances increased, the cells shrank and the shape of the cells changed from smooth and rounded to spiky and angulated. With regard to its muscle-relaxing effect, it was not possible to distinguish the specimens fixed in magnesium-containing fixatives from those without. In this study it was not possible to prove any relaxing effect of magnesium ions added to the fixative. On the contrary the magnesium ions caused an increase in the osmolarity, with significant changes in both the morphometry and the morphology of the human detrusor smooth muscle cells.

Adult↗
PubMed1997

p53 nuclear immunoreactivity as a predictor of response and outcome following chemotherapy for metastatic bladder cancer.

p53 nuclear immunoreactivity was determined in primary bladder tumours from 50 patients who developed metastatic bladder cancer. We investigated the relationship between p53 nuclear immunoreactivity and the response and outcome following chemotherapy. p53 nuclear accumulation was detected in 48% of the primary tumours using the PAb1801 antibody in archival paraffin-embedded tissue sections. All patients received platinum-based combination chemotherapy including methotrexate for metastatic disease. The response to chemotherapy did not relate to the prevalence of p53 nuclear overexpression: 50% of the patients expressing p53 nuclear reactivity achieved a response compared to 27% of those without p53 expression (P = 0.14); overall, 38% of the patients responded. The median survival after chemotherapy was 5.9 months; 8.4 months for patients with p53 nuclear reactivity compared to 5.2 months for those without (P = 0.38). Multivariate analysis showed that performance status but not p53 nuclear status was an independent prognostic factor for survival following chemotherapy. The results indicate that patients with p53 nuclear immunoreactivity in the primary bladder tumour do not have a lower response rate or poorer outcome following chemotherapy for metastatic disease than do patients without p53 nuclear reactivity.

Adult↗
PubMed1997

Micropipette aspiration of human erythrocytes induces echinocytes via membrane phospholipid translocation.

When a discocytic erythrocyte (RBC) was partially aspirated into a 1.5-microns glass pipette with a high negative aspiration pressure (delta P = -3.9 kPa), held in the pipette for 30 s (holding time, th), and then released, it underwent a discocyte-echinocyte shape transformation. The degree of shape transformation increased with an increase in th. The echinocytes recovered spontaneously to discocytes in approximately 10 min, and there was no significant difference in recovery time at 20.9 degrees C, 29.5 degrees C, and 37.4 degrees C, respectively. At 11 degrees C the recovery time was significantly elevated to 40.1 +/- 6.7 min. At 20.9 degrees C the shape recovery time varied directly with the isotropic RBC tension induced by the pipetting. Sodium orthovanadate (vanadate, 200 microM), which inhibits the phospholipid translocase, blocks the shape recovery. Chlorpromazine (CP, 25 microM) reversed the pipette-induced echinocytic shape to discocytic in < 2 min, and the RBC became a spherostomatocyte-II after another 30 min. It was hypothesized that the increase in cytosolic pressure during the pipette aspiration induced an isotropic tension in the RBC membrane followed by a net inside-to-outside membrane lipid translocation. After a sudden release of the aspiration pressure the cytosolic pressure and the membrane tension normalized immediately, but the translocated phospholipids remained temporarily "trapped" in the outer layer, causing an area excess and hence the echinocytic shape. The phospholipid translocase activity, when not inhibited by vanadate, caused a gradual return of the translocated phospholipids to the inner layer, and the RBC shape recovered with time.

Blood Specimen Collection↗
PubMed1997

Intestinal interleukin-8 concentration and gene expression in inflammatory bowel disease.

BACKGROUND: Interleukin-8 (IL-8) is an important cytokine for recruitment and activation of polymorphonuclear neutrophils (PMNs), cells that are abundant in the intestinal lesions of ulcerative colitis (UC) and Crohn's disease (CD). The present investigation was conducted to evaluate intestinal IL-8 concentration and IL-8 gene expression in parallel in inflammatory bowel disease (IBD) patients and a non-inflammatory control group. METHODS: The intestinal concentration of IL-8 was measured with a sandwich enzyme-linked immunosorbent assay (ELISA) technique (detection limit, 17.4 pg/mg protein), and relative quantitation of IL-8 mRNA transcript levels was done with a reverse transcription polymerase chain reaction (RT-PCR)-based method. Biopsy specimens from 66 humans who underwent colonoscopy--28 with UC, 18 with CD and colonic involvement, and 20 non-inflammatory disease-specific controls who subsequently were found to fulfill the diagnostic criteria for irritable bowel syndrome (IBS)--were included. None had received glucocorticoids within 3 months. RESULTS: Using a one-tailed variance analysis, a significant concordance between increasing IL-8 protein concentrations and disease activity was found both in UC and CD (P < 0.001), and only trace amounts were detected in IBS biopsy specimens. No differences were found between the two groups of UC and CD patients (P > 0.05), and no differences were found between quiescent IBD and IBS (P > 0.05). However, the PCR method showed IL-8 mRNA in 8 of 18 CD patients (44.4%; 95% confidence limits, 21.5-69.2%) and 7 of 28 UC patients (25.9%; 95% confidence limits, 11.1-46.3%), as compared with 0 of 20 IBS (P < 0.005). Increased IL-8 mRNA levels were found only in active CD, which was not the case in UC. No correlation was found between intestinal IL-8 ELISA and IL-8-mRNA levels (r = 0.24, P > 0.05). CONCLUSIONS: The observed correlation between disease activity and expression of the IL-8 gene in active CD colitis but not in UC and the increased IL-8 protein concentrations in affected intestinal segments of IBD as compared with the non-inflamed IBS indicate a possible transient IL-8 gene expression or altered mRNA stability in UC and CD, as is well known for other cytokines, such as IL-2. If so, it may form the basis of new therapeutic regimens for IBD like IL-10.

Adult↗
PubMed1997

Long-term efficacy of intravesical bacillus Calmette-Guerin for carcinoma in situ: relationship of progression to histological response and p53 nuclear accumulation.

PURPOSE: We assessed the influence of the histological response to intravesical bacillus Calmette-Guerin (BCG) and the prevalence of p53 nuclear accumulation on the clinical behavior of patients with carcinoma in situ. MATERIALS AND METHODS: Of 60 patients with Bergquist grade 3 carcinoma in situ 13 had primary and 47 had secondary carcinoma in situ. Patients received 6 weekly instillations and nonresponders received an additional 6 instillations at 2-week intervals. No maintenance was administered. Median followup was 48 months. The p53 nuclear accumulation was detected by immunohistochemical analysis with antibody PAb 1801. RESULTS: The complete histological response rate to BCG therapy was 64%, which decreased to 52% at 4 years. BCG was more effective for treatment of primary than secondary carcinoma in situ (complete response rate 85 versus 57%, respectively). The 45% progression rate was related to the initial histological response occurring in 26% of patients with a complete versus 77% with a partial and no response. Consequently, the progression rate was only 8% for primary versus 57% for secondary carcinoma in situ. Of the patients receiving only 1 course of BCG 40% had progression compared to 62% of those who received 2 courses. Patients in whom both courses failed had a progression rate of 89%. Intravesical BCG converted the p53 nuclear immunoreactivity from positive to negative in 73% of the 26 patients expressing reactivity before treatment, of whom 68% also had a complete response. The progression rate was related to the prevalence of p53 nuclear reactivity after but not before treatment (90% of patients with versus 37% without p53 nuclear accumulation had progression). All 3 complete responders with p53 nuclear reactivity after BCG had progression, which suggests that molecular genetic change may precede histological change. Complete responders without p53 nuclear accumulation after BCG treatment experienced the lowest progression rate (21%). CONCLUSIONS: Our results suggest that patients with a persistent complete histological response and without p53 nuclear accumulation after BCG treatment can be followed conservatively. Cystectomy should be considered in all other patients.

Adjuvants, Immunologic↗
PubMed1997

Prognosis of vulvar dysplasia and carcinoma in situ with special reference to histology and types of human papillomavirus (HPV).

Sixty-one women with vulvar dysplasia or carcinoma in situ were treated with local laser excision of the initial lesion and of the recurrences, and followed at intervals of from 3 increasing to 12 months. Recurrences were observed in 16 (26%) patients. No case of invasive carcinoma was seen. Patients with recurrences were significantly younger than those without (P < 0.02, median age 42.5 and 54 years, respectively). The resection borders were significantly more often involved in the initial lesions in the group with recurrences (36%) than in the group without (9%) (P < 0.014). All lesions were classified according to the WHO (mild, moderate, severe dysplasia or carcinoma in situ) and Toki et al. (1991) (warty, basaloid, combined warty/basaloid or mixed (warty, basaloid and simple). No pure types of Toki (1991) could be demonstrated. There were no differences regarding recurrences in any of these groups. HPV DNA was detected in the initial lesions by PCR in 50/56 (89%) (44 with HPV type 16 and 6 with HPV type 33) and by ISH in 23/61 (38%). The same type of HPV could be demonstrated in all first recurrences except in two, where HPV types 33 was shown in specimens harboring HPV type 16 in the initial lesions. In one of these cases, HPV type 16 could again be demonstrated in the second and final recurrence. In no specimen was more than one type of HPV detected. The results indicate that the most important parameter in predicting the recurrence of vulvar dysplasia or carcinoma in situ is the involvement of the resection borders. The location of the lesion, the degree and type of dysplasia, and the type of HPV seem to play a minor role. Local excision and subsequent intensive control with removal of any visible new lesion probably prevents development of vulvar invasive carcinoma.

Adult↗
PubMed1996

Evidence for two tumor suppressor loci associated with proximal chromosome 9p to q and distal chromosome 9q in bladder cancer and the initial screening for GAS1 and PTC mutations.

The most common genetic alteration identified to date in bladder cancer is loss of heterozygosity (LOH) of chromosome 9, suggesting the presence of possible tumor suppressor genes on this chromosome. We attempted to map the location of these genes by analyzing 69 primary transitional cell carcinomas of the bladder with a panel of microsatellite markers for LOH on chromosome 9. Monosomy 9 (defined by LOH of all informative markers analyzed on 9p and 9q) was detected in 26 of 69 (38%) tumors, and 22 of 69 (32%) tumors showed subchromosomal deletions. Twelve tumors (17%) demonstrated partial LOH of chromosome 9 and indicated two distinct regions of LOH. Eight tumors showed distal allelic loss of 9q with a minimal region of common deletion flanked proximally by marker GSN on 9q33. Six tumors showed proximal allelic loss of 9p and 9q with a minimal area of common deletion flanked by markers D9S970 on 9p12 and D9S283 on 9q21. Two tumors showed loss of both the distal region of 9q and the proximal region of 9p and 9q, which were separated by a possible 6-44 cM of retained genetic material. The proximal minimal area of common deletion excluded 9q22.3-q31 to where two putative tumor suppressor genes, the nevoid basal cell carcinoma syndrome and multiple self-healing squamous epithelioma (ESS1) genes, have been mapped. The growth arrest-specific gene (GAS1), a candidate tumor suppressor gene, was included within the proximal minimal region. We evaluated the GAS1 gene for its potential role in bladder cancer using single-strand conformational polymorphism to screen for mutations in GAS1 in 10 bladder cancer cell lines and 14 primary bladder tumors. A polymorphism at codon 88 was noted in one primary bladder tumor, but no other abnormalities were found, suggesting that another potential tumor suppressor gene important to bladder cancer resides in these minimally deleted regions. Because the nevoid basal cell carcinoma syndrome gene has long been speculated to be a putative tumor suppressor gene in bladder cancer and this gene has recently been characterized as the human homologue of the Drosophila patched gene (PTC), 20 primary bladder tumors with chromosome 9q LOH were screened for mutations in PTC using single-strand conformational polymorphism and heteroduplex analysis. No alterations were found in any of the samples analyzed. Furthermore, 4 of 37 noninvasive papillary (Ta) tumors demonstrated loss of all 9q markers with retention of 9p, whereas no Ta tumor showed loss of 9p with retention of all 9q markers, suggesting that LOH of 9q is the earlier event in bladder tumorigenesis. In summary, our results indicate two tumor suppressor loci associated with proximal chromosome 9p to q and distal chromosome 9q that may be important in bladder cancer. GAS1 and PTC do not seem to be frequently mutated in bladder cancer.

Carcinoma, Transitional Cell↗
PubMed1996

Stabilization of triple-stranded oligonucleotide complexes: use of probes containing alternating phosphodiester and stereo-uniform cationic phosphoramidate linkages.

Pyrimidine oligonucleotides containing alternating anionic and stereo-uniform cationic N-(dimethylamino-propyl)phosphoramidate linkages [e.g. d(T+T-)7T, d(T+T-)2(T+C-)5T and (U'+U'-)7dT, where U' is 2'-O-methyluridine)] are shown to bind to complementary double-stranded DNA segments in 0.1 M NaCl at pH 7 to form triple-stranded complexes with the pyrimidine.purine.pyrimidine motif. For each of the sequences investigated, one stereoisomer bound with higher affinity, and the other stereoisomer with lower affinity, than the corresponding all-phosphodiester oligonucleotide. The stereoisomer of d(T+T-)7T that interacted weakly with a dT.dA target in 0.1 M NaCl formed a novel dA.dA.dT triple-stranded complex with poly(dA) or d(Al5C4A15) in 1 M NaCl; in contrast, the stereoisomer that bound strongly to the dT.dA target failed to form a dA.dA.dT triple-stranded complex.

DNA Probes↗
PubMed1996

Presence of sulphatide (3'-sulphogalactosylceramide) in pericytes in the choroid layer of the eye: sharing of this glycolipid autoantigen with islets of Langerhans.

The aim of the study was to investigate the distribution in the eye of sulphatide, an acid glycolipid which has previously been demonstrated in islets of Langerhans, nervous tissue and in kidney glomeruli of diabetic patients, and against which antibodies have been found in patients with newly diagnosed insulin-dependent diabetes mellitus. A specific monoclonal antibody, Sulph I, was used for detection of sulphatide by thin-layer chromatography, and light and electron microscope immunohistochemistry. A distinct, patchy staining was found in the choroid layer and the ciliary processes. The antigen was confirmed to be sulphatide and its concentration in human eyes was 30 nmol sulphatide/g wet tissue. By electron microscopy, anti-sulphatide choroid labelling was demonstrated in pericytes and in smooth muscle cells surrounding vessels. No Sulph I-negative pericytes were seen. Double labelling with Sulph I and anti-smooth muscle actin revealed that only pericytes in the eye contained sulphatide and not those in heart, lung, liver, adrenal, spleen, lymph node, thymus, or pancreatic tissue. Thus, sharing of the autoantigen sulphatide has been demonstrated between islets of Langerhans and pericytes in the choroid layer of the eye.

Aged↗