Paranasal sinus bony anatomic variations and mucosal abnormalities: CT analysis for endoscopic sinus surgery

Coronal plane computerized tomographic (CT) scanning has dramatically improved the imaging of paranasal sinus anatomy as compared to sinus radiographs. Increasingly, subtle bony anatomic variations and mucosal abnormalities of this region are being detected. Data regarding the “background” prevalence of these findings are needed to determine their clinical relevance. A detailed analysis of coronal plane CT scans of the paranasal sinuses obtained in 202 consecutively imaged patients was conducted. Special attention was directed toward identifying bony anatomic variations and mucosal abnormalities. Anatomic variations studied included pneumatization of the middle turbinate, paradoxical curvature of the middle turbi-nate, Haller's cells, and pneumatization of the unci-nate process. Such bony anatomic variations were detected in 131 (64.9%) of 202 patients and were found with a similar frequency in patients scanned for sinus complaints and in those scanned for nonsinus reasons. Mucosal abnormalities were detected in 168 (83.2%) of 202 patients. For those patients scanned during the evaluation of sinus-like complaints, mucosal abnormalities were noted in 153 (92.2%) of 166 cases, and were predominantly detected in the anterior ethmoid region. For patients scanned during nonsinus evaluations, mucosal abnormalities were detected in 15 (41.7%) of 36 cases, without predilection for the anterior ethmoid region. Discussion regarding the prevalence and clinical significance of paranasal sinus bony anatomic variations and mucosal abnormalities is included as a guide to assist the otolaryngologist and/or radiologist in the evaluation of coronal sinus CT scans.     

Histology of a lengthened human tibia.

We describe the histology of a specimen taken from an amputated leg seven months after a 15 cm bone gap in the tibia had been closed by bone transport. Lengthening appeared to have occurred by repeated minor trauma to the bone, with the fractured trabeculae in sufficiently close contact for the repair process to proceed. Osteogenesis did not occur through a cartilage phase, but the fracture gaps were bridged by collagen fibres, around which new bone formed. Microfractures had repaired by primary healing with woven bone and with no microcallus. Small regions of bone were necrotic. Resorption of the necrotic bone and remodelling of the immature bundle and woven bone were still at an early stage, suggesting that complete remodelling in man may take years rather than months.     

Patch clamp studies on the kinetics and selectivity of N-methyl-d-aspartate receptor antagonism by memantine (1-amino-3,5-dimethyladamantan)

Memantine (1-amino-3,5-dimethyladamantan) was tested as an antagonist of N-methyl-d-aspartate (NMDA) receptors on cultured superior collicular and hippocampal neurones using the patch clamp technique and its actions were compared to those of Mg²⁺ ions, ketamine, dextrorphan, dextromethorphan, phencyclidine and dizocilpine (MK-801). Memantine (2–33 μM) concentration-dependently antagonized responses to NMDA 100 μM with an IC₅₀ of 2.92 ± 0.05 μM. In contrast, current responses to (S)-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (l-AMPA 50–100 μM) and γ-amino butyric acid (GABA 10 μM) were unaffected by Memantine 8 μM. Memantine 8 μM caused a non-parallel shift of the NMDA concentration-response curve to the right in a manner indicative of uncompetitive open channel block. The effects of memantine were similar to ketamine in that both antagonists were weakly use- and strongly voltage-dependent. In contrast, MK-801, phencyclidine and dextrorphan showed much slower kinetics that was reflected in their marked use- and weaker voltage-dependency. The antagonistic effects of memantine were not reversed by increasing concentrations of glycine (0.1–100 μM) ruling out the possibility of an interaction of memantine with the strychnine-insensitive glycine modulatory site associated with the NMDA receptor-channel complex. Memantine (1–100 μM) also selectively antagonized responses to NMDA (40 μM) in the cortical wedge preparation with IC₅₀ of 12.9 ± 1.5 μM.     

The in vivo microdialysis recovery of dopamine is altered independently of basal level by 6-hydroxydopamine lesions to the nucleus accumbens

The present study was designed to test the hypothesis that the active neurotransmitter processes of release and uptake affect the in vivo microdialysis recovery of dopamine (DA) in the nucleus accumbens (N ACC) of the rat. The in vivo recovery for DA was established for rats which had received either unilateral infusions of the neurotoxin 6-hydroxydopamine (6-OHDA, 8 μg) or vehicle (0.2 μg ascorbate). In the quantitative dialysis method used (point of no net flux method), DA is added to the perfusate at concentrations above and below the expected extracellular concentration (0, 5, 10 and 20 nM) and DA is measured in the dialysate from the brain to generate a series of points. A linear fit is performed, the slope of which is the in vivo recovery of the dialysis probe. The in vivo recovery of the 6-OHDA group was 30 ± 3% which was significantly lower (P < 0.002) than the in vivo recovery of the control group which was 60 ± 3% (mean ± SEM; n = 6/group). The zero intercept of this regression is the point of no net flux, which is the extracellular concentration of DA independent of the probe sampling characteristics. The extracellular DA concentration for the 6-OHDA group was 7.8 ± 1.1nM, which was not significantly different than the control group which was 6.9 ± 0.7nM. The tissue DOPAC/DA ratios of the 6-OHDA lesioned hemispheres were significantly higher than the contralateral hemispheres of the same animals (0.62 ± 0.1vs.0.27 ± 0.1; P < 0.02) while the DOPAC/DA ratios in the control group were not significantly different (0.24 ± 0.1vs.0.27 ± 0.1). The fractional DA efflux from the terminals in the 6-OHDA group was significantly higher than the fractional DA efflux of the control group (0.52 ± 0.08vs.0.03 ± 0.003; P < 0.0001), indicating that the remaining terminals have increased turnover of DA. Despite the increased turnover, however, the number of remaining release and uptake sites are not sufficient to maintain the high in vivo recovery observed in the control group.     

Radical radiotherapy for T4 carcinoma of the skin of the head and neck: A multivariate analysis

Sixty-seven patients with 68 stage T4 carcinomas of the skin of the head and neck were treated with radical radiotherapy at the University of Florida between October 1964 and November 1989. Thirty-three lesions were previously untreated and 35 were recurrent. Twenty-nine lesions were squamous cell carcinomas, 37 were basal cell carcinomas, and 2 were basosquamous carcinomas. Minimum follow-up was 2 years. The 5-year local control, local control including surgical salvage, and cause-specific survival probabilities were 53%, 74%, and 75%, respectively. Local control rates with radiotherapy alone were poorer in patients with recurrent lesions (41% vs. 67%, p = .07) or bone involvement (40% vs. 62%, p = .08). Results were analyzed by multivariate methods using local control, local control with surgical salvage, and cause-specific survival as endpoints. The parameters analyzed were histology; size of primary lesion; previous treatment (previously untreated vs. recurrent); involvement of bone, nerve, or cartilage; and skeletal muscle invasion. Three important prognostic factors were identified, each predictive of poorer ultimate local control and cause-specific survival rates: (a) bone involvement (p < .01); (b) recurrent lesions (p < .01); and (c) nerve involvement (p < .02). Radiotherapy alone can control advanced carcinomas of the skin of the head and neck, although lesions that have recurred after prior treatment and those with involvement of bone or nerve are associated with a lower likelihood of cure.     

Fibronectin levels in male ejaculate and evidence for its role in unexplained infertility

Vasovasostomy has become a popular and highly successful method of restoring fertility to those who have undergone a vasectomy. However, there is a high correlation between vasostomy and antisperm antibody production leading to spontaneous sperm agglutination and immobilization. There is still considerable disagreement on whether antibodies are the primary causative agent. Our study provides evidence that fibronectin, a ubiquitous glycoprotein whose major function is cell-to-cell adhesion, could be a "subfertility" factor and contribute to male "unexplained infertility." Semen from control, random, and vasovasostomy populations was studied using a sophisticated enzyme-linked immunosorbent assay (ELISA). The results show that fibronectin is significantly present in all groups. The mean concentrations (micrograms/mL) were 753.9 for control, 566.4 for random, followed by significantly higher 1267.3 for the vasovasostomy group (p less than 0.05). The spermatozoa were assayed for bound fibronectin by flow cytometry. The mean percentage of cells bound after background subtract was 29.7 for control and 48.2 for the vasovasostomy group; the difference was significant (p less than 0.05). We conclude that fibronectin is present in semen and bound to sperm cells in great concentrations for individuals having undergone surgical insult and may contribute to male infertility particularly by sperm agglutination.     

Quantitative autoradiography of nicotinic [H]acetylcholine binding sites in rat brain

Quantitative autoradiography was used to localize nicotinic [³H]acetylcholine (ACh) binding sites in rat brain. High concentrations of nicotinic [³H]ACh binding sites were observed in the anterior and medial nuclei of the thalamus, the medial habenula and the superficial layer of the superior colliculus. Moderate levels of binding sites were observed in a variety of brain regions such as the frontoparietal cortex and the hippocampus. Low levels of nicotinic ACh sites occurred throughout the hypothalamus and the primary olfactory cortex.