Dynamic Interaction of Craniofacial Structures during Head Positioning and Direct Laryngoscopy in Anesthetized Patients with and without Difficult Laryngoscopy

Background: We lack fundamental knowledge of the mechanisms of difficult laryngoscopy despite its clinical significance. The aim of this study was to examine how head positioning and direct laryngoscopy alter arrangements of craniofacial structures.

Methods: Digital photographs of the lateral view of the head and neck were taken at each step of head positioning and direct laryngoscopy in age- and body mass index-matched patients with (n = 13) and without (n = 13) difficult laryngoscopy during general anesthesia with muscle paralysis. The images were used for measurements of various craniofacial dimensions.

Results: Both simple neck extension and the sniffing position produced a caudal shift of the mandible and a downward shift of the larynx, resulting in an increase of the submandibular space. Direct laryngoscopy during the sniffing position displaced the mandible and tongue base upward and caudally, and the larynx downward and caudally, increasing the submandibular space and facilitating vertical arrangement of the mandible, tongue base, and larynx to the facial line. These structural arrangements in response to direct laryngoscopy were not observed in patients with difficult laryngoscopy, whereas head positioning produced similar structural arrangements in patients with and without difficult laryngoscopy.     

Preemptive analgesia by zaltoprofen that inhibits bradykinin action and cyclooxygenase in a post-operative pain model

The post-operative pain state results from a barrage of primary afferent inputs exposed to products of tissue damage such as bradykinin and prostaglandins and the central sensitization by the continuing inputs. This provides the rationale for preemptive analgesia, whereby the blockade of primary afferent inputs prior to injury may result in a reduction of post-operative pain. 2-(10,11-dihydro-10-oxo-dibenzo[b,f]thiepin-2-yl) propionic acid (zaltoprofen) is a unique compound that inhibits cyclooxygenase (COX) and exhibits anti-bradykinin activity. The present study evaluated the preemptive analgesic effect of zaltoprofen in a post-operative pain model produced by plantar incision. When orally, but no intrathecally, administered 30 min prior to incision, zaltoprofen significantly increased the withdrawal threshold 2 h and 1-3 days after incision at 10 mg/kg. While the bradykinin B1 antagonist des-Arg10-HOE-140, the selective COX-1 inhibitor SC-560, and the selective COX-2 inhibitor celecoxib did not affect post-operative pain, the B2 antagonist HOE-140 dose-dependently relieved the post-operative pain at 2-200 microg/kg with a time course similar to that of zaltoprofen. The B2 receptor mRNA was expressed in the hindpaw and the expression did not change before and 24 h after surgery. These results suggest that zaltoprofen produces the preemptive analgesic effect peripherally by blocking the B2 pathway.     

Hindquarters vasoconstriction through central GABA(B) receptors in conscious rats

The exogenous application of GABA into the cisterna magna of the freely moving rat decreases hindquarters vascular tone as well as arterial pressure. GABA could influence GABA receptor subtypes A, B or C. However, the hindquarters vascular response to the stimulation of each receptor subtype has not yet been investigated. The present study therefore characterized the response to the GABA(B) receptor agonist baclofen injected into the cisterna magna of the conscious rat. Intracisternally injected baclofen induced long-lasting increases in hindquarters vascular resistance and arterial pressure in a dose-dependent manner. Both actions induced by baclofen were completely blocked by a prior intracisternal injection with the GABA(B) receptor antagonist CGP 35348 (p-[3-aminopropyl]-p-diethoxymethylphosphinic acid), and systemically by ganglionic blockade. These actions of baclofen were also abolished centrally by sodium pentobarbital anaesthesia. The results suggest that GABA(B) receptor stimulation via the cisterna magna induced hindquarters vasoconstriction, probably due to central disinhibition of sympathetic activity.     

Lysosome is a primary organelle in B cell receptor-mediated apoptosis: an indispensable role of Syk in lysosomal function

To investigate the mechanism of B cell receptor (BCR)-mediated apoptosis, we utilized immature B cell lines, DT40 and WEHI-231. In both cell lines, BCR-crosslinking caused the increase in lysosomal pH with early apoptotic changes characterized by chromatin condensation and phosphatidylserine exposure. This increase was detected in c-Abl-deficient DT40 cells but not in Syk-deficient cells, which corresponded to the fact that the former cells but not the latter revealed BCR-induced apoptosis. In contrast, BCR-crosslinking caused no apparent change in mitochondrial transmembrane potential. Therefore, the lysosomal change might be a primary event in BCR-induced apoptosis in DT40 cells. The increased activity of cathepsin B and apoptosis-preventing effect of a cathepsin inhibitor suggested a significant role of lysosomal enzymes in this apoptosis. By microscopic studies, lysosomes of wild-type DT40 cells fused to BCR-carrying endosomes became enlarged and accumulated one another. In contrast, these changes of lysosomal dynamics did not occur in Syk-deficient cells but transfer of wild-type Syk restored the lysosomal changes and apoptosis. These results demonstrated that the lysosomal change accompanied with the activation of lysosomal enzymes is a primary step in BCR-crosslinking-mediated apoptosis and Syk is responsible for this step through the fusion of BCR-carrying endosomes to lysosomes.     

Mediolateral intercalation in planarians revealed by grafting experiments.

We investigated how planarians organize their left-right axis by using ectopic grafting. Planarians have three body axes: anteroposterior (A-P), dorsoventral (D-V), and left-right (L-R). When a small piece is implanted into an ectopic region along the A-P and D-V axes, intercalary structures are always formed to compensate for positional gaps. There are two hypotheses regarding L-R axis formation in this organism: first, that the left and right sides of the animal may be recognized as different parts, and L-R intercalation can induce midline structures (asymmetry hypothesis); second, that both sides may have symmetrical positional values, and mediolateral (M-L) intercalation creates positional values along the L-R axis (symmetry hypothesis). We performed ectopic grafting experiments in the head region of the planarian, Dugesia japonica, to examine these hypotheses. A left lateral fragment containing a left auricle was implanted into the medial region of the host. Ectopic structures were always formed only on the left side of the graft, where lateral tissues abutted onto the medial tissues. However, no morphologic change was induced on the right side of the graft, where left-sided tissues faced onto right-sided tissues. Molecular marker analyses indicated that ectopic structures formed on the left side of the graft were induced by M-L intercalation, supporting the "symmetry hypothesis." When the midline tissues were implanted into a lateral region, they induced a complete ectopic head, demonstrating that M-L intercalation may be sufficient to establish the L-R axis in planarians.     

The effect on the bones of condensed phosphate when used as food additives: Its Importance in Relation to Preventive Medicine

Based on the fact that chemical products such as binding agents are produced by mixing three kinds of phosphates with different ratios, we mixed metaphosphate, polyphosphate and pyrophosphate. Each was made to Na-phosphate, K-phosphate, and Ca-phosphate and each was mixed with commercial feeds so that the content of P would be approximately 0.1, 0.15, 0.3, 0.4, 0.6 and 1.0%. The prepared pellets were given to ICR, CF # 1 and AKR strains of mice at 29 days of age for 680 days and observations were made through this experimental period at different stages. The observations were also carried out on the mice administered with the experimental feeds for 1.5 months from 9 to 10.5 months of age. The observations were compared with those of the control group at all times. As a result, plasma 1 α, 25 (OH)₂ D₃ and P levels were always significantly higher in the phosphate administered groups relative to the control. Urine P and Fe increased while urine Ca decreased in the phosphate-treated groups. The effect of phosphates on the bones was studied taking soft X-ray pictures of hind legs and applying microdensitometry to them. Through these observations we recognized thinning of the cortex of bones, reduction of marrow trabecules and development of osteophyte. Histological observations disclosed that changes in knee joint tissues were apparent; that is, a decrease in or an irregular loss of the number of cells in superficial, intermediate, and radial strata of the joint cartilage, proliferation of subchondral bone, and the development of osteophytes were noted. As for muscles, diameters of musclar fibers became smaller; in particular, type II fibers showed greater shrinkage. Regarding kidneys, swelling and atrophy of glomerular capillaries, proliferation of mesangial cells, nephroselerosis, swelling, thinning, and loss of tubular epithelium, interstitial tissue inflammation, development of cylindruria, and deposition of calcium were observed. All these changes seem to be a particularly advanced aspect of the changes which are more pronounced with increasing dose and age. These changes were found even in the group administered with the feed containing 0.1% phosphorus, and, these changes were dependent on the concentration level of P. It was observed that administration to older subjects for a short term (1.5 months) produced effects stronger than those to younger subjects administered for a long term (10.5 months). The effects of condensed Ca-phosphate on bones were similar to those of condensed Na- and K-phosphates, and, hence, it was supposed that these effects were caused by phosphate radicals. An erratum to this article is available at .     

Carcinoma of the cervix: Value of dynamic magnetic resonance imaging in assessing early stromal invasion

Background The purpose of this study was to assess the accuracy of contrast-enhanced magnetic resonance imaging (dynamic MR imaging) in the evaluation of preinvasive and early invasive cancer of the cervix. Methods Twenty-nine women with untreated squamous cell carcinoma of the cervix with either no stromal invasion or early stromal invasion underwent pretreatment MR imaging and dynamic MR imaging within 4 weeks of surgical evaluation. The images were evaluated for tumor detection and compared with results of histologic examination of the surgical specimens. Results The lesions in 17 cases with histologically proven stromal invasion of 4 mm or greater were detected with dynamic MR imaging, whereas lesions in only 8 of these cases were detected with T2 imaging. In 9 cases with stromal invasion between 4.0 mm and 5.0 mm, lesions were represented as early phase focal enhancement on dynamic MR images, but not detected on T2-weighted images. In the 12 cases with less than 4 mm stromal invasion, no lesions were visualized on either T2-weighted images or dynamic MR images, except in 1 case of glandular involvement without stromal invasion that appeared as enhancement on early-phase dynamic MR imaging. Conclusion Dynamic MR imaging detected more lesions of early stromal invasion in pretreatment imaging for cervical cancer than nonenhanced MR imaging.