Adolescent body mass indices and self-perception

This study examined the relationship between body mass index (BMI) of adolescents and their perceived-weight status and self-concept, controlling for confounding factors. The data base was drawn from the High School and Beyond (HSB) study, which included 17,318 females and 15,878 males. BMI was calculated using self-reported weights and heights. Response variables included a self-concept index and evaluation of the statement "I am overweight." While respondents' perception of overweight status was accompanied by higher mean BMI values, there were discrepancies in perceived-weight and BMI-weight status. Logistic regression of explanatory variables on perception of overweight status revealed that BMI was the strongest predictor, gender was the second strongest, and the odds of perception of overweight status were higher for females than males by a factor of more than eight. Ordinary least squares regression of explanatory variables on the self-concept index revealed that perception of normal weight status, lower BMI, and male gender were strong predictors of positive self-concept. The findings indicate that substantial numbers of teenage females perceive themselves as overweight when BMI values suggest they are not, while males have a reasonably accurate weight perception.     

The effect of ultrasonics on sealer distribution and sealing of root canals

The purpose of this study was to compare the ultrasonic and hand methods of sealer placement using three types of sealers: Sultan "Grossman's formula," AH-26, and CRCS. The effect of these methods on radiographic density, sealer distribution, and on the apical seal of the different sealers was evaluated. The in vitro experiment was carried out using human extracted mandibular incisors and mesio-buccal roots of maxillary first and second molars. Following standardized canal instrumentation, 120 single canal mandibular incisors were randomly assigned to six groups, depending on the type of sealer and method of sealer placement (hand versus ultrasonic). An additional ten teeth were used as controls. In the molar groups 40 canals were randomly assigned to two groups, with the method of sealer placement as the variable. Eight canals were used as controls. Postsealer analyses using radiographic density scores transformed to mm of sealer indicated that ultrasonics was superior to manual placement only for CRCS. Taken together, our investigation suggests that ultrasonics may enhance the placement of some sealers (i.e. CRCS) but not of others (i.e. AH-26 or Sultan). Method of sealer placement had no effect on apical leakage and therefore apparently on apical seal.     

Atraumatic gastric transposition after transhiatal esophagectomy

Transhiatal esophagectomy using the stomach for esophageal replacement requires that the gastric "neoesophagus" be transferred from the peritoneal cavity through the posterior mediastinum into the neck under blind conditions. This process is associated with stretching, tearing, and hematoma formation in the most critical portion of the gastric tube, that to be used for the anastomosis. A technique is described for this procedure that is simple to perform and, most importantly, completely atraumatic to the gastric conduit.     

Measuring beliefs about orthodontic treatment: a questionnaire approach

OBJECTIVES: Few studies have examined what parents and orthodontists expect from and value about orthodontic treatment. In this study, we designed and tested a questionnaire to outline what drives consumer demand for children's orthodontic care. Further, we present data from the questionnaire to illustrate how expectations and values pertaining to orthodontic treatment relate to sociodemographic variables. METHODS: Subjects were 220 Pennsylvania orthodontists and 220 parents at a university orthodontic clinic who were administered a questionnaire designed to assess what parents and orthodontists value about and expect from orthodontic treatment. Items for the questionnaire were developed via a qualitative, telephone interview process. Data were analyzed using factor analysis and reliability analysis for scale development, and analysis of variance for preliminary validity assessment. RESULTS: Through factor analysis, the questionnaire was reduced from 84 to 52 items, and eight scales were examined: expected treatment benefits, expected treatment risks (short- and long-term), expected treatment inconveniences, value of treatment benefits, value of risks (short- and long-term), and value of treatment inconveniences. For parents, the reliability for all scales was in the acceptable range. For orthodontists, only the "short-term risks" scale failed to attain an acceptable reliability. Preliminary validity was assessed through examining relationships between demographic variables and subscale scores. For parents, income, father's education level, and sex of respondent were related to treatment expectations and values. For orthodontists, age, sex, and patient volume were related to treatment values. CONCLUSIONS: The questionnaire developed in the present study was found to be practical and reliable for use with providers and consumers of orthodontic care and can be used to explore factors affecting the demand for orthodontic care. Implications of possible unrealistic treatment expectations on the part of orthodontists and parents also are discussed.     

牛奶中乳糖含量的测定

牛奶是生活中不可或缺的营养品,乳糖是牛奶的重要组成成分之一,测定牛奶中乳糖的含量可以确定牛奶是否掺假。目前牛奶中乳糖的测定方法有很多,主要从旋光仪法、比色法、酶化学法、离子色谱电化学修饰法、高效液相色谱法、近红外光谱法以及光折射法做了主要介绍。     

有机锡化物在芳香醛合成中的应用

制备了纤维素氧磷－钯配合物催化剂，详细考察了催化剂对三（正）丁基锡氢化物和酰卤化合物偶联反应的催化作用。结果表明，该负载型高分子配合物催化剂对偶联反应具有很高的催化活性和化学选择性，分离容易，可重复使用，用XPS方法对催化机理进行了研究。     

Intracellular mucin production by lobular breast carcinoma cells

Slides from ten cases of infiltrating lobular and ten of in situ lobular breast cancer were studied with mucicarmine stain to determine the incidence of intracellular mucin in such cases. Nine of the ten infiltrating carcinomas and six of the ten in situ tumors contained such cells. None of the cases contained infiltrating duct or "colloid" carcinoma and none had in situ carcinoma of major ducts.     

Immunotherapy and chemotherapy in children with neuroblastoma

Recent advances with immunotherapy in animal tumors suggested that trials with a combination of chemotherapy and immunotherapy in human malignant tumors might be worthwhile. A pilot program with Vibrio cholera neuraminidase-treated tumor cells plus BCG was tested in 3 patients who had had chemotherapy for disseminated neuroblastoma. Two of these children were in "complete remission" after radiation therapy and chemotherapy before the administration of immunotherapy. Relapse occurred in 5-6 months in all 3 patients. These disappointing results are discussed in relation to problems of current chemotherapy in disseminated neuroblastoma including results obtained at second-look operations in patients obtaining "complete remission."     

Transient elevation of serum thyroid hormone concentration after initiation of replacement therapy in myxedema

Measurements of thyroid hormone concentrations in serum are commonly used to determine the proper dose of hormone replacement. We have noted that early in the course of thyroxine (T4) replacement in myxedema, serum T4 concentrations may be transiently elevated before reaching a lower "steady-state" level. This observation is illustrated in a study of six patients. Serum T4, free thyroxine index, and triiodothyronine (T3) rose to peak concentrations at 2 to 6 weeks, 35% to 120% above the values achieved 4 to 8 months later. Values were transiently in the thyrotoxic range in five of the six patients. This phenomenon is most likely due to a decrease in the metabolic clearance rate of the absorbed hormone associated with hypometabolism. Thus, serum T4 and T3 concentrations during the first 6 months of therapy do not reflect the optimal dose of T4 replacement on a long-term basis.     

Experience-dependent plasticity in adult rat barrel cortex

This study tested the hypothesis that the receptive fields (RFs) of neurons in the adult sensory cortex are shaped by the recent history of sensory experience. Sensory experience was altered by a brief period of "whisker pairing": whiskers D2 and either D1 or D3 were left intact, while all other whiskers on the right side of the face were trimmed close to the fur. The animals were anesthetized 64-66 h later and the responses of single neurons in contralateral cortical barrel D2 to stimulation of whisker D2 (the center RF) and the four neighboring whiskers (D1, D3, C2, and E2; the excitatory surround RF) were measured. Data from 79 cells in four rats with whiskers paired were compared to data from 52 cells in four rats with untrimmed whiskers (control cases). During the period of whisker pairing, the RFs of cells in barrel D2 changed in three ways: (i) the response to the center RF, whisker D2, increased by 39%, (ii) the response to the paired surround RF whisker increased by 85-100%, and (iii) the response to all clipped (unpaired) surround RF whiskers decreased by 9-42%. In the control condition, the response of barrel D2 cells to the two neighboring whiskers, D1 and D3, was equal. After whisker pairing, the response to the paired neighbor of D2 was more than twice as large as the response to the cut neighbor of D2. These findings indicate that a brief change in the pattern of sensory activity can alter the configuration of cortical RFs, even in adult animals.