Orienting otolith-ocular reflexes in the rabbit during static and dynamic tilts and off-vertical axis rotation.

Orienting otolith-ocular reflexes were assessed in rabbits using static tilt, off-vertical axis rotation (OVAR) and sinusoidal oscillation about earth-horizontal axes. In all paradigms, head pitch produced ocular counter-pitch and vergence, and head roll produced ocular counter-roll and conjugate yaw version. Thus, vergence and version are essential components of orienting reflexes along the naso-occipital and bitemporal axes. Vergence and version caused misalignment between the axes of eye and head movement during pitch and roll head movements. Semicircular canal input broadened the band-pass of these orienting reflexes, which would make them more appropriate when compensating for head movement during active motion.

Orientation of the eyes to gravitoinertial acceleration.

Orientation of the eyes to gravitoinertial acceleration, i.e., to the sum of gravity and the linear accelerations acting on the head and body, is a basic property of the linear vestibulo-ocular reflex to support vision. Present in a wide range of species from the lateral-eyed rabbit to frontal-eyed monkeys and humans, the eyes deviate in pitch, roll and yaw in response to pitch, roll and yaw head movements. The eyes also converge in response to naso-occipital linear acceleration. This paper provides examples of ocular orientation generated by static tilt and off-vertical axis rotation in three dimensions and demonstrates specifically how vergence would support vision in the rabbit.

Effect of combining ultrasonography and ultrasound-guided fine-needle aspiration biopsy findings for the diagnosis of thyroid nodules.

OBJECTIVE: To assess the accuracy of ultrasonography and cytology in predicting malignancy in thyroid nodules. DESIGN: Prospective open study. SETTING: Thyroid centre, Japan. SUBJECTS: 329 nodules in 309 patients examined by a new ultrasound scanner and ultrasound-guided fine-needle aspiration biopsy. INTERVENTIONS: Comparison of ultrasonographic, cytological, and combined diagnosis with the histological diagnosis. MAIN OUTCOME MEASURES: Sensitivity, specificity, and accuracy of each diagnostic method. RESULTS: The sensitivity, specificity, accuracy were 84%, 87%, 85% for cytological diagnosis, and 82%, 91%, and 87% for ultrasonographic diagnosis. By using ultrasonographic diagnosis when cytological specimens were inadequate or gave false negative results, the sensitivity, specificity, and accuracy went up to 89%, 91%, and 90%, respectively. We could not diagnose follicular carcinomas accurately by combined cytology and ultrasonography. CONCLUSION: The combination of ultrasonography and cytology improves the accuracy of diagnosis of thyroid nodules, but is less effective with follicular tumours.

Canal and otolith afferent activity underlying eye velocity responses to pitching while rotating.

Pitching the head while rotating (PWR) combines periodic activation of the semicircular canals and the otoliths to generate pitch and roll eye deviations and continuous horizontal nystagmus. Monkeys were tested after individual pairs of semicircular canals were plugged and single units were recorded in the vestibular nerve while the animals were sinusoidally pitched 20-40 deg about a spatial horizontal axis with 5- and 16-s periods and simultaneously rotated about a spatial vertical axis at 30-120 deg/s. As previously shown, the steady-state horizontal response disappeared after plugging the vertical semicircular canals, but was maintained when the lateral canals were plugged. When the left anterior and right posterior canal (LARP) pair was left intact, the steady-state response depended on the axis about which the pitching took place. When the axis was normal to the LARP plane, there was no steady-state response. When the pitching axis was perpendicular to the LARP normal, the response was maximal. Firing rates of otolith units were approximately in phase with pitch position, and the addition of rotation about a vertical axis did not change the response. Lateral canal units did not have a steady-state modulation during pitch or constant velocity rotation. During PWR, they oscillated at twice the pitch frequency. This corresponded to the frequency at which the canal was maximally activated as it aligned with the plane of rotation. The amplitude of modulation increased proportionally to rotational velocity, but the phase remained the same. These characteristics were unchanged during roll while rotating (RWR), which induces little continuous nystagmus. Anterior and posterior canal units were maximally excited near pitch-velocity maxima and minima, respectively, during pure pitching. During PWR, however, the phases of both components simultaneously shifted toward each other and toward being in phase with otolith units. The peak excitation tended toward a forward-pitch position when the rotation was to the ipsilateral side, and toward a backward pitch position when the rotation was to the contralateral side. With 120-deg/s rotation during a 16-s pitch period, the phase difference between anterior and posterior canal units was as small as 17 deg. These data support the postulate that the correlation between vertical canal and otolith units is the critical factor in generating continuous unidirectional horizontal nystagmus during PWR.

Prognostic features of cervical dysplasia associated with specific types of HPV DNA and cytologic features characteristic of HPV infection in dysplasia.

OBJECTIVE: To study a possible etiologic relationship between the prognosis of uterine cervical dysplasia, association of type-specific human papillomavirus (HPV) DNA and cytologic features characteristic of HPV infection. STUDY DESIGN: Two hundred thirteen cases of uterine cervical dysplasia were selected in which follow-up survey for more than two years was possible. Frequency of the presence of HPV DNA in the DNA samples was determined by polymerase chain reaction. The cervical scrapings were also examined microscopically for the frequencies of cells with cytologic features characteristic of HPV infection. RESULTS: HPV was positive in 98 cases (46.0%). The high-risk type of HPV was detected at almost the same frequencies in both progressive and regressive states of dysplasia. Cytologic features were more evident in cells infected with the low-risk type of HPV. CONCLUSION: Involvement of an as-yet-unknown factor or factors coupled with infection with the high-risk type of HPV is implicated in the progression of uterine cervical dysplasia. Cytologic features characteristic of HPV infection may serve as a diagnostic marker for a favorable prognosis in dysplasia.

Isometamidium concentrations in the sera of cattle maintained under a chemoprophylactic regime in a tsetse-infested area of Zimbabwe.

An experiment was carried out to determine the concentrations of the trypanocidal drug isometamidium chloride in the sera of cattle maintained under a chemoprophylactic regimen at Rekomitjie, Zimbabwe, an area of high tsetse challenge in the Zimbabwe valley. In February 1993, 24 cattle at this site were treated intramuscularly with isometamidium chloride at a dose of 1.0 mg/kg body weight. Thereafter all animals were monitored regularly for 6 months for the presence of trypanosomes and sera were collected to determine the concentrations of isometamidium using an ELISA. Isometamidium treated cattle appeared to be protected against trypanosome infections for at least 18 weeks following treatment. Thereafter, three trypanosome infections were detected, between 20 and 22 weeks following treatment. In contrast, in 18 untreated control cattle at the same site, 9 trypanosome infections were detected over the first 18 weeks of the experiment. Quantification of the isometamidium concentration in sera from the drug treated cattle indicated that the apparent half-life of isometamidium in these animals was 23 days. This was similar to the half-life observed previously in cattle treated under laboratory conditions. The isometamidium ELISA was shown to be capable of quantifying drug levels in 20 out of 23 cattle for at least 70 days after treatment. There was no evidence of drug resistant trypanosomes at this site.

[CD26/dipeptidyl peptidase IV and thyroid peroxidase as molecular markers for differentiated thyroid carcinoma].

Differential expression of two enzymes, dipeptidyl peptidase IV (CD26/DPP IV) and thyroid peroxidase (TPO), in neoplastic thyroid tissues was studied by Northern blot analysis and histochemical analysis using 31 thyroid tissue specimens of various thyroid diseases. On Northern blot analysis, all 16 differentiated carcinomas (12 papillary and 4 follicular carcinomas) overexpressed CD26/DPP IV mRNA, whereas all 14 benign tissue specimens (4 normal thyroid, 4 Graves' disease, 2 adenomatous goiters and 4 follicular adenomas) showed faint expression of CD26/DPP IV mRNA. All 14 benign tissues expressed high levels of TPO mRNA, whereas all 12 papillary carcinomas strongly underexpressed TPO mRNA. A medullary carcinoma did not show any mRNA expression of either enzyme. TPO mRNA expression in differentiated carcinomas did not always correlate with mRNA expression of thyroglobulin, thyroid stimulating hormone receptor, and thyroid transcription factor-1. Northern blot analysis also revealed that CD26/DPP IV is a more specific marker of differentiated carcinoma than three proto-oncogenes previously reported to increase mRNA expression in thyroid carcinomas: c-met, c-erbB-2, and EGF-R. Histochemically, all 14 benign tissues were CD26/DPP IV negative and strongly TPO positive, while all 12 papillary carcinomas were strongly CD26/DPP IV positive and TPO negative. Three of 4 follicular carcinomas were histochemically positive for the two enzymes. These findings suggest that the differential expression of these two enzymes can be applied to study the thyroid tumorigenesis.

Immunohistological differentiation of benign thyroid follicular cell tumors from malignant ones: usefulness of anti-peroxidase and JT-95 antibodies.

An immunohistological investigation using anti-thyroid peroxidase (PO) and JT-95 (JT) antibodies was conducted on surgical specimens of papillary carcinoma (n = 12), follicular carcinoma (n = 8), follicular adenoma with prominent papillary structure (n = 12), follicular adenoma (n = 8) and adenomatous goiter (n = 8). In benign lesions, follicle-forming and papillae-forming epithelia showed positive staining with anti-PO antibody. In 26 of 28 benign lesions, PO-positive areas covered 50% or more of the cut surface area of the lesions. However in carcinomas, PO-positive areas were non-existent (13/20) or only focal (7/20) and the papillae did not stain. The incidence of JT-positive cases was higher in papillary carcinomas (12/12) than in other lesions (13/36). JT-positive areas were much wider than PO-positive areas in papillary carcinomas, whereas in benign lesions, PO-positive areas were wider than or at least roughly equal to, JT-positive areas. Follicular carcinomas did not stain or stained only focally with these antibodies. In conclusion, these two antibodies seem useful in differentiating benign from malignant follicular cell tumors.