Small unilateral jaw gap variations: equilibrium changes, co-contractions and joint forces

Summary  After complex prosthetic reconstructions, small differences in vertical distances between the left and right side of the jaw may occur during jaw closing, nevertheless providing bilateral tooth contacts in intercuspation by small deformations of the mandible. Their effects on the co-contraction of the masticatory muscles, the temporomandibular joint reaction forces, and the point of application of the resultant bite force vector in the maxillary occlusion plane – the so-called reduction point – have not been investigated, thus far simultaneously in one sample. The main goal of this study was to investigate variations of these measures in an experimental intercuspation simulated by one anterior and two posterior force transmission points.     

Extremely high avidity association of Fe(III) with the sickle red cell membrane

Red blood cells (RBCs) from patients with sickle cell anemia and thalassemia carry abnormal accumulations of molecular Fe(III) at the cytosol/membrane interface. The avidity of the red cell membrane for this iron has not been defined. Using open ghost membranes prepared from sickle RBC, we examined the ability of membrane-associated Fe(III) to resist removal by 15 chelators representing a 40-log range of affinities for Fe(III). Efficacy of chelators was compared with literature values for their idealized affinity for iron as represented by the cummulative stability constant (beta n), their effective stability constant reflecting affinity under biologic conditions (Keff), and an indicator of their ability to chelate Fe(III) in the presence of an insoluble phase of iron (Ksol). Deferoxamine, a very high affinity chelator having log beta n = 30.6, was found to be the lowest affinity chelator able to remove RBC membrane Fe(III). Regardless of chelator beta n, only those agents able to preserve log Keff > or = 12 were able to do so, indicating that the membrane's effective avidity for Fe(III) is on the order of 10(12). Additional confirmation that membrane avidity for Fe(III) is extremely high is found in the observation that only chelators having log Ksol > 0 were effective. Potential physiologic iron chelators in cytoplasm of pathologic red cells are unable to prevent or reverse iron accumulation on the membrane because they do not have sufficiently high affinity for iron. These data argue that RBC membrane Fe(III) is truly pathologic.     

Effect of blood in the gut on measurements of endogenous carbon monoxide production

Changes induced in measurements of endogenous carbon monoxide (CO) production by blood in the lumen of the gut were studied in five normal volunteers. The study was undertaken because exogenous heme is absorbed by intestinal mucosal cells where the porphyrin ring is split with the release of CO that could contribute to blood CO levels and lead to a fallacious diagnosis of hemolytic disease. Volunteers who consumed 200 ml of their own blood doubled their endogenous production of CO (0.69 versus 0.34 mumoles/kg/hr). This suggested that at least 3% of the ingested heme was degraded and recovered as CO within 2 1/2 hr. Measurements of serum bilirubin also showed a significant increase after ingestion of blood. These data indicate that blood in the gastrointestinal tract can interfere with quantification of heme and bilirubin turnover from measurements of either endogenous CO production or bilirubin and suggest that this might occur with the ingestion of meat.     

Case report of comorbid schizophrenia and obsessive compulsive disorder in a patient who was tube-fed for four years by family members because of his refusal to eat

概述

在许多精神障碍中（包括强迫症和精神分裂症），拒食是常见的表现。当突然出现拒食时，这可能需要急诊处理；一旦变成慢性，它就成为一种难以改变的根深蒂固的行为。对拒食患者的诊断可能有难度，尤其是对有共病问题、智力受损或对自身状况缺乏自知力的患者。鼻饲是一种有效的短期干预方法，当患者重新进食时即可中止这一干预。然而，在某些情况下，患者可能变得依赖于鼻饲。我们介绍一个病例，报告一名患有精神分裂症、强迫症、边缘智力以及癫痫的患者由于拒绝进食而由其家庭成员用鼻饲管喂食超过三年。

中文全文

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