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T Otto

Publications and source records attributed to T Otto.

At least 19 recordsLinked to original sources
PubMed1992

Neuronal activity in the hippocampus during delayed non-match to sample performance in rats: evidence for hippocampal processing in recognition memory.

Neuronal activity in the CA1 of rats was explored with regard to functional correlates of performance in an odor-guided continuous delayed non-match to sample task. Although different CA1 cells fired in association with each identifiable trial event, these analyses focused on cells that fired selectively during the period of odor cue sampling and response generation. The firing patterns of many of these cells reflected the match or non-match comparison between current and previous odor cues independent of the particular stimuli that composed those comparisons. Such cells were more prevalent in sessions when performance was highly accurate. Hippocampal cells did not demonstrate stimulus-evoked firing that persisted through the memory delay, nor did they fire differentially to session-novel vs. repeated odor presentations. These results suggest that the hippocampus contributes to recognition memory by processing comparisons between current information and representations of previous stimuli stored in parahippocampal and neocortical structures.

Animals↗
PubMed1992

Complementary roles of the orbital prefrontal cortex and the perirhinal-entorhinal cortices in an odor-guided delayed-nonmatching-to-sample task.

Continuing efforts toward designing odor-guided tasks for rats that are similar in memory demands to tasks used typically with primates have resulted in the development of a continuous delayed-nonmatching-to-sample (cDNM) task that is guided by olfactory stimuli. The results indicate that normal subjects acquire the cDNM task rapidly and that subsequent performance deteriorates with increases in memory delay or interitem interference. Moreover, different aspects of cDNM performance were shown to be differentially sensitive to selective lesions of the orbitofrontal and parahippocampal areas. Orbitofrontal cortex lesions disproportionately impaired cDNM acquisition; delay performance was impaired only under conditions of elevated levels of interitem interference. Combined perirhinal and entorhinal cortical lesions had no effect on cDNM acquisition but impaired cDNM performance at longer delays across all levels of interference. Fornix lesions did not impair either acquisition of cDNM or subsequent performance across long delays and increased interference. This pattern of impaired and spared capacities is similar to that observed in monkeys after lesions of analogous areas and is consistent with the notion that the prefrontal cortical system contributes preferentially to learning general task "rules" such as the nonmatching rule that is inherent in cDNM, whereas the perirhinal and entorhinal cortical areas are involved in the intermediate-term maintenance of memories for specific information.

Animals↗
PubMed1992

Lectins in diagnosis of bladder carcinoma.

With the purpose of studying changes in the expression of glycoconjugate structures in nonmalignant and cancerous lesions of urothelium the lectins ConA, TKA, PNA, DBA, STA, LFA, UEA, MPA, RCA, LCA, GSA1, SBA, GSA2, WGA, PHA and Lot were tested in formalin-fixed, paraffin-embedded tissue sections of (1) cold biopsies from normal urothelium and bladder cancer of different grades (G1-G3) in humans, (2) normal transitional epithelium and N-butyl-N(4-hydroxybutyl)nitrosamine (BBN)-induced bladder cancer in animal experiments (Wistar rat), and (3) human transitional cancer cell line HT 1376. In human urothelium TKA and SBA were positive markers demonstrating positive staining reactions in all tumor grades without binding to normal epithelium. They stained also the human transitional carcinoma cell line HT 1376 (G3). In Wistar rats DBA, ConA, LCA, SBA, GSA2 and WGA had a specific affinity to BBN-induced carcinoma. Findings of positive lectin marker in transitional cell cancer may offer progress in diagnostics and therapy.

Animals↗
PubMed1991

Learning-related patterns of CA1 spike trains parallel stimulation parameters optimal for inducing hippocampal long-term potentiation.

Recent studies have revealed 3 stimulation parameters that together comprise the temporal pattern of neuronal activation optimal for the induction of hippocampal LTP: high-frequency bursts, activity 100-200 ms prior to a burst, and burst delivery in phase with the ongoing hippocampal theta rhythm. The present paper reports that these 3 aspects of patterned neural activity, collectively referred to as "theta-bursting," are characteristic of the spike trains of CA1 pyramidal cells in rats during the sampling and analysis of learning cues in an odor discrimination task and during performances of a spatial memory task. In contrast, theta-bursting occurs relatively infrequently during behavioral events less directly related to task-relevant mnemonic processing. These findings suggest that the optimal conditions for the induction of LTP occur naturally in behaving animals, time-locked to behavioral events critical to learning.

Animals↗
PubMed1991

[Carcinoma in situ of the urinary bladder--definition and status of treatment].

Carcinoma in situ is a noninvasive intraepithelial disease without papillary growth. Anaplasia and a disarranged growth form of the epithelium are histopathological characteristics. Carcinoma in situ can appear as a secondary disease combined with a papillary tumour or after transurethral resection of a papillary tumour. On the other hand, primary carcinoma in situ is also known to appear without a papillary tumour. Symptoms of cystitis are often seen. Sometimes, however, the disease does not cause any symptoms. Urinary cytology is the most important noninvasive investigation, followed by biopsy of the bladder epithelium. Treatments commonly applied at present are intravesical immunotherapy with BCG and intravesical chemotherapy. Photodynamic laser therapy is presently being investigated. Carcinoma in situ is very significant as a prognostic factor. The progression rate is up to 83%, and progression signifies development of a poorly differentiated invasive bladder cancer. The treatment of choice for inefficiently treated carcinoma in situ is cystectomy. The urinary diversion selected in men depends on the histopathological findings in the prostatic urethra; an ileum neobladder, the standard diversion in men, cannot be performed if carcinoma in situ has been found in the prostatic urethra.

Administration, Intravesical↗
PubMed1991

[Animal experiment aspects of bladder cancer].

Many aspects of bladder cancer remain obscure under clinical conditions. The natural course of the illness is seldom known in human patients, in whom only the treated natural history is subject to investigation. Cancer research in animals can complement clinical investigations. The following experimental set-ups are of importance; chemically induced bladder cancer; transplantation of human urothelial carcinoma in immunodeficient nude mice (xenograft model); transplantation of clinically induced bladder cancer in syngenetic animals (syngenetic model). These models are used for tumour induction and the development of immunotherapy, chemotherapy and new techniques. The extrapolation of these experimental results to clinical situations is being discussed. Some experimental results are of interest for practising urologists, e.g. increased incidence of tumour development in dilated upper urinary tract or in the bowel segment after urinary diversion; new therapeutic approaches such as breakdown of multidrug resistance to chemotherapy or administration of photodynamic therapy; planning of intravesical therapy relating to aspects of cell proliferation.

Animals↗