Biomedical subjects

P Tauchi

Publications and source records attributed to P Tauchi.

4 recordsLinked to original sources

PubMed2000

Sentinel node staging for cutaneous melanoma in a university-affiliated community care setting.

BACKGROUND: The feasibility of intraoperative lymphatic mapping and sentinel lymphadenectomy (SLND) in settings other than high-volume specialized clinics has been questioned. We sought to determine the feasibility of SLND in a university-affiliated private teaching hospital. METHODS: A multidisciplinary sentinel node program was established to include surgeons, nuclear medicine physicians, and pathologists. Within this program, 79 patients with cutaneous melanoma underwent attempted SLND after cutaneous lymphoscintigraphy (CL), between January 1994 and December 1998. All sentinel nodes were examined by hematoxylin-eosin staining and determined whether negative for evidence metastatic disease by both S-100 and HMB 45 immunohistochemical staining. RESULTS: CL was successful in 77 (97%) of 79 patients. A total of 88 lymphatic basins were found to be at risk for metastatic disease by CL. SLND was not successful in the two patients who did not have a successful CL. Sentinel nodes were identified in all but three patients with the remaining 88 lymphatic basins (technical success, 97%). There was one false negative in this group of patients (approximately 1%). CONCLUSIONS: SLND is a highly accurate way of staging the regional node basin. Our technical success rates and false-negative rates indicate the feasibility of this approach in settings other than high-volume specialty clinics.

Feasibility Studies↗

PubMed1994

Stereotactic fine needle aspiration of mammographic lesions.

Stereotactic fine needle aspiration biopsy (FNAB) is being offered at many centers across the United States in lieu of open surgical biopsy for nonpalpable mammographic lesions. To determine how accurate this procedure is in a community hospital, the authors performed stereotactic FNAB of 62 nonpalpable mammographic lesions using Siemens upright stereotactic equipment. FNAB was immediately followed by hook wire localization and open biopsy. Ten lesions were histologically malignant. Seven of these had been identified cytologically as atypical, suspicious or malignant. Three carcinomas were undetected by FNAB, for a sensitivity rate of 70 percent. There were no false-positive FNAB diagnoses. Three different radiologists performed the FNAB and localizations. Our results were insufficiently sensitive to be able to offer stereotactic FNAB to patients in lieu of open surgical biopsy. We are currently planning to evaluate the dedicated stereotactic prone biopsy equipment to compare the results of needle core biopsies with subsequent hook wire localization and open biopsy.

Biopsy, Needle↗

PubMed1988

Ultralow vestibuloocular reflex time constants.

We report detailed oculomotor studies in 3 patients with central nervous system lesions and markedly decreased time constants (less than 2 seconds) of the vestibuloocular reflex (VOR). In 1 patient with Chiari type I malformation, serial measurements over 3 years documented a progressive decrease in the duration of postrotatory nystagmus (100 deg/sec steps, acceleration 140 deg/sec2) until finally there was no sustained nystagmus. At this time, the patient had no response to caloric stimulation or to sinusoidal rotation below 0.2 Hz but normal gain (peak slow-phase eye velocity/peak chair velocity) above 0.4 Hz (phase lead increased). Gaze holding, saccades, smooth pursuit, and optokinetic nystagmus were normal, but optokinetic-after-nystagmus disappeared. The other 2 patients (combined brainstem-cerebellar atrophy) had impaired gaze holding, abnormal smooth pursuit and optokinetic nystagmus, and absent optokinetic-after-nystagmus. VOR gain to step and high-frequency sinusoidal stimuli was increased. The neural mechanism that normally prolongs the VOR time constant may have reduced it in our patients.

Adult↗

PubMed1983

Dynamic pupillary response controlled by the pupil size effect.

Pupillary escape has been described as an initial contraction followed by a slow redilatation, occurring in response to a step stimulus of low-intensity light. When the initial pupil size is small, the response to the same step stimulus is pupillary capture, a steady and sustained contraction. In this experiment a comparison was made between three modes of controlling pupil size and thereby of regulating the pupillary response: contralateral light background level, ipsilateral light background level, and accommodative level with which there is no change in retinal adaptation. All three level setting modes showed similar results in illustrating the pupil size effect. In addition, an inhibitory effect was found with both ipsilateral and contralateral light backgrounds that is independent of Weber's Law in the contralateral case. Our results lead to the formulation of a binocular model, featuring an internal parameter control whereby a signal dependent on the static pupil size regulates the gains of the parallel phasic and tonic pathways, the former responsive to transient changes of light, and the latter to background levels of light and accommodative levels. Our findings also raise interesting questions concerning the loci of these complex interactions in the simple neuroanatomy of the pupillary pathways.

Humans↗