Clinico-radiological findings of neuroendocrine tumour metastases to the orbit.

PURPOSE: We present the clinico-radiological findings of neuroendocrine tumour metastases to the orbit. METHODS: This was a multicentre, retrospective study of patients with neuroendocrine tumour metastases to the orbit. Data was collected from medical records across five different sites within Australia and the United Kingdom. RESULTS: Nine patients (eleven lesions) were identified. The most common presenting complaint was diplopia (5/9, 56%). Disease occurred bilaterally in two patients. Seven patients (78%) had extraocular muscle involvement. The lateral recti (4/9, 44%) and superior recti (2/9, 22%) were the most commonly affected. Ocular presentation preceded primary tumour diagnosis in three patients (33%). On orbital imaging, metastases were most commonly reported as well circumscribed, ovoid or round, heterogeneous, contrast-enhancing masses. Features of intralesional haemorrhage and bony invasion are uncommonly reported. CONCLUSIONS: Neuroendocrine tumour metastasis to the orbit is uncommon. Metastases have a propensity for the extraocular muscles, commonly presenting as heterogeneous, well circumscribed, contrast-enhancing lesions on neuroimaging. New ocular symptoms, a history of neuroendocrine tumours, and these radiological findings, should lead to high clinical suspicion of metastatic disease. Atypical findings warrant biopsy to exclude other causes of orbital lesions.

Hypercapnic ventilation response in patients with lung disease: improved accuracy by correcting for ventilation ability.

The hypercapnic ventilation response (HCVR) is positively correlated with forced expired volume in 1 s (FEV1). Therefore, subjects of small stature or patients with lung disease have low values for HCVR. However, indexing the HCVR for the subject's predicted maximal voluntary ventilation (MVV) results in a corrected HCVR (CHCVR) which is not dependent on FEV1 in normal subjects [Respiration 1993;60:197-202]. We hypothesized that the CHCVR would also be useful in assessing chemosensitivity in patients with poor lung function. To obtain the predicted MVV, we used the linear regression for FEV1 vs. measured MVV obtained from 411 patients with a wide range of FEV1 values (MVV = 31.2 x FEV1 + 11.8, r = 0.90, p < 0.001). We compared HCVR and CHCVR to the occlusion pressure response to hypercapnia (OPRH) in 34 patients with chronic obstructive pulmonary disease (COPD) and in 19 patients with low FEV1 due to small stature. All patients had been referred for assessment of possible sleep apnea. The results for the two groups of patients were similar. For the COPD patients, the HCVR had high values for sensitivity (86%) and negative predictive value (94%), but specificity, positive predictive value and accuracy were low (59, 35 and 65%, respectively). In contrast, CHCVR had high values for all the foregoing (86, 96, 100, 100 and 97%, respectively). Our results suggest that the CHCVR is useful in assessing chemosensitivity in patients who are ventilation-limited.

Normal values for the hypercapnic ventilation response: effects of age and the ability to ventilate.

Normal values reported for the hypercapnic ventilation response (HCVR) vary considerably, but the reported normal values have come from studies containing small sample sizes and/or the subjects were young or of unidentified age. We speculated that age has a major effect on HCVR due to the generally lower maximal ventilation (VEmax) of elderly subjects. Therefore, we performed a large study to more accurately define the normal range and to reveal any effects which age and sex might have on HCVR. We studied 181 normal subjects (69 males, 112 females) between the ages of 20 and 93 years. Prior to measuring HCVR we measured forced expired volume in 1 s (FEV1) and forced vital capacity to establish whether lung function was normal and to obtain an estimate of VEmax. Results for the entire group revealed a significant correlation between FEV1 and HCVR [HCVR = 0.51 + (0.33 FEV1), r = 0.43, p < 0.001], so it is clear that the ability to ventilate can influence HCVR. We also found a significant correlation between age and HCVR [HCVR = 2.08-(0.01.age), r = 0.34, p < 0.001]. The mean HCVR for our male group (1.86 +/- 0.54 l/min.mm Hg) was significantly higher (p < 0.001) than that for the females (1.37 +/- 0.60) even though their mean ages were similar (41.3 vs. 41.7 years, respectively). We expect that this difference in HCVR was due to the higher FEV1 in males compared to females (3.82 vs. 2.83 liter, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Fluorescence study of a field-induced director reorientation in a liquid crystalline polyacrylate.

The electric field-induced director reorientation is investigated by fluorescence spectroscopy and turbidimetry. The dynamics of this reorientation are studied as a function of temperature, applied voltage, and frequency.

Fluorescence study of field-induced director reorientations in low mass liquid crystalline compounds.

The Frederickz transition and the dynamic scattering deformation in 4-alkyloxy-4'-cyanobiphenyl compounds are investigated by fluorescence spectroscopy and turbidimetry. The main characteristics of the Frederickz deformation, reversibility and threshold voltage, in the nematic and the smectic A phase are investigated by means of fluorescence spectroscopy. Furthermore, the dynamics of the Frederickz transition are studied as a function of temperature and applied voltage. The results obtained with both techniques are compared and correlate well.