Effects of respiration on soft palate movement in feeding.

Cyclic soft palate elevation is temporally associated with masticatory jaw movement. However, the soft palate is normally lowered during nasal breathing to maintain retropalatal airway patency. We tested the hypothesis that the frequency and amplitude of soft palate elevation associated with mastication would be reduced during inspiration. Movements of radiopaque soft palate markers were recorded by videofluorography while 11 healthy volunteers ate solid foods. Breathing was monitored with plethysmography. Masticatory sequences were divided into processing and stage II transport cycles (food transport to the oropharynx before swallowing). In food processing, palatal elevation was less frequent and its displacement was smaller during inspiration than expiration. In stage II transport, the soft palate was elevated less frequently during inspiration than expiration. These findings suggest that masticatory soft palate movement is diminished during inspiration. The control of breathing appears to have a significant effect on soft palate elevation in mastication.

Intrahepatic biliary endoscopy in sclerosing cholangitis.

Sclerosing cholangitis is usually diagnosed by clinical findings coupled with radiographic imaging of the bile ducts by ERCP. Direct imaging of both the intra- and extrahepatic biliary tree provides an opportunity to further study this disorder and its potential complications such as biliary malignancy. However, endoscopic visualization of the intrahepatic bile ducts in sclerosing cholangitis is potentially limited by the size of available cholangioscopes and the presence of strictures. Below, we report our initial results using a 0.8-mm fiberoptic endoscope placed through a partially steerable 1.8-mm guide catheter. The system allows visualization of the intrahepatic biliary tree beyond areas of stricture in the more distal ducts.

Evolutionarily conserved alternative pre-mRNA splicing regulates structure and function of the spectrin-actin binding domain of erythroid protein 4.1.

A developmental alternative splicing switch, involving exon 16 of protein 4.1 pre-mRNA, occurs during mammalian erythropoiesis. By controlling expression of a 21-amino acid peptide required for high-affinity interaction of protein 4.1 with spectrin and actin, this switch helps to regulate erythrocyte membrane mechanical stability. Here we show that key aspects of protein 4.1 structure and function are conserved in nucleated erythroid cells of the amphibian Xenopus laevis. Analysis of protein 4.1 cDNA sequences cloned from Xenopus erythrocytes and oocytes showed that tissue-specific alternative splicing of exon 16 also occurs in frogs. Importantly, functional studies with recombinant Xenopus erythroid 4.1 demonstrated specific binding to and mechanical stabilization of 4.1-deficient human erythrocyte membranes. Phylogenetic sequence comparison showed two evolutionarily conserved peptides that represent candidate spectrin-actin binding sites. Finally, in situ hybridization of early embryos showed high expression of 4.1 mRNA in ventral blood islands and in developing brain structures. These results demonstrate that regulated expression of structurally and functionally distinct protein 4.1 isoforms, mediated by tissue-specific alternative splicing, has been highly evolutionarily conserved. Moreover, both nucleated amphibian erythrocytes and their enucleated mammalian counterparts express 4.1 isoforms functionally competent for spectrin-actin binding.

A utility analysis of dental implants.

By applying a utility (usefulness) scale termed the "Feeling Thermometer" to 111 edentulous patients, a measure of effectiveness (quality-adjusted prosthesis years) that can be compared across several treatment strategies was developed. The results suggest that the utility scale was a valid (known group, P < .05), reliable (intraclass correlation coefficient = .713) measure of patients' preferences for the three treatment strategies: (1) conventional complete dentures (controls, n = 77), (2) transosteal implant-supported prostheses (n = 19), and (3) endosseous implant-supported prostheses (n = 15). The implant-treated patients rated their prostheses as high or higher (Feeling Thermometer score of 86.3 [endosseous] and 82.3 [transosteal]) than a functional fitting, esthetic conventional denture (score of 85.0 [endosseous] and 82.0 [transosteal]). They were also younger, more educated, and had received more sets of dentures (P < .05) than conventional denture patients.

Peak B endorphin concentration in cerebrospinal fluid: reduced in chronic pain patients and increased during the placebo response.

The level of an endogenous opioid (peak B endorphin) was measured in chromatographically fractionated cerebrospinal fluid (CSF) sampled from two groups of chronic pain patients before and after intrathecal saline (placebo) injection. As assessed by a verbal rating scale, one group reported no change in their level of pain (non-responders, NR; n = 6) while the other group reported complete or greater than 50% pain relief (placebo responders, PR; n = 14). We find, as has been reported previously, that initial peak B levels were lower (by 50%) in these chronic pain patients' CSF than in CSF from pain-free (PF) normal controls (P less than 0.001, t-test). Peak B levels measured from CSF of the NR group undergoing this procedure did not change (P greater than 0.4, paired t-test). In contrast, a significant 2.3-fold increase was measured in the CSF peak B level of the PR group (P less than 0.05, paired t-test). This is the first direct evidence that a CSF opioid is correlated with placebo pain relief in chronic pain patients. Peak B is a potent analgesic substance when administered by the intracerebroventricular route in mice and its level is related to the patients' pain status in a presumably causal manner.

Local analgesia without anesthesia using peripheral perineural morphine injections.

Twenty-five patients with chronic pain were treated with nerve blocks. They were divided into two groups, A and B, according to the volume of local anesthetic required for surgical anesthesia by standard nerve block techniques. The 16 patients in group A had pain in the distribution of small nerves, which could be blocked with 5 ml or less. They were blocked in a random, double-blind crossover fashion using 0.5% bupivacaine or 0.02% morphine. The nine patients in group B were injected simultaneously with saline, 30 ml perineurally and 1 ml intramuscularly. Morphine (6 mg) was added, in a random, double-blind fashion, to one of the injections. A second pair of injections was subsequently done, using morphine by the alternative route. Perineural morphine provided statistically longer lasting pain relief than did either intramuscular morphine or perineural bupivacaine.

Relief of postlaminectomy syndrome in selected patients by injection of autogenous cerebrospinal fluid.

We have been using the differential spinal block to study patients referred to our Pain Clinic for treatment of their chronic pain syndromes. In a selected group of chronic-pain patients from whom cerebrospinal fluid (CSF) could not be obtained at the L4 or L5 interspace, administration of autogenous CSF obtained at a higher interspace gave immediate and complete but temporary pain relief. Endorphins were present in these autogenous CSF samples. These studies, indicating that CSF even from chronic-pain patients contains analgesic substances (possibly endorphins), may point to new treatment modalities for certain chronic back pain syndromes.