Anteroposterior tibiofemoral displacements during isometric extension efforts. The roles of external load and knee flexion angle

Rehabilitation of knee extensors is a major consideration in patients with cruciate injuries and repairs. Extension exercises, however, can produce undesirable loads on the injured or replaced anterior cruciate ligament (ACL) resulting in permanent stretch of this restraint. Our study measures the tibiofemoral displacements associated with proximal, middle, and distal locations of the external resisting force and knee flexion angles of 30 degrees, 60 degrees, and 90 degrees. Our results show that tibiofemoral displacements are dependent on both location of the external resisting force and knee flexion angle, with anterior displacements being associated with distal displacement of the resistance pad. The results suggest that patients with ACL injuries or repairs conduct extension exercises with a proximal position of the resistance pad to minimize loads and prevent stretching of this constraint.     

Transfer of nongenetic thermostability from genetically thermostable to genetically thermolabile poliovirus

Summary Adding the genetically thermostablecr ⁱ mutant of the Akron strain of type 1 poliovirus to the genetically thermolabile Akronca ³⁰ mutant before infection of monkey kidney tissue culture sheets resulted in an average 17-fold increase in the heat-surviving fraction of theca ³⁰ virus progeny. Mixing the 2 viruses after infection did not result in any increase. The progenies of at least most of these thermostable transferee particles were thermolabile. By this criterion the transferred thermostability was at least mainly nongenetic.Aided by grant from National Foundation.     

Morphology of the fetal rat testis preserved in different fixatives

Histopathological examination of the testes of exposed fetuses and neonates is important in assessing the developmental effects of environmental toxins, including sex hormone modulators. Modified Davidson's fluid (mDF) has been suggested as a superior substitute for Bouin's fluid for fixation of adult animal testes. We compared the morphology of fetal rat testes stained with hematoxylin and eosin (H&E) or immunochemically after fixation in 10% neutral buffered formalin (NBF), Bouin's fluid, or mDF. Fixation in mDF resulted in more sharply defined nuclear detail and better preservation of cellular cytoplasm on H&E-stained sections of rat testes on gestation day 19. Use of Bouin's fluid did not allow satisfactory detection of apoptotic cells by fluorescent terminal deoxynucleotide transferase-mediated deoxy-UTP nick labeling. Staining with the immunoperoxidase system and the conventional chromogen diaminobenzidine tetrahydrochloride to visualize 5-bromo-2-deoxyuridine-positive cells demonstrated that the number of positive nuclei and intensity of staining were similar with all 3 fixatives. Immunostaining for cytoskeletal protein vimentin was more intense and provided better details of the Sertoli cell cytoplasm with formalin fixation than with mDF. Our study demonstrates that fixation in mDF provided better morphologic detail in the fetal rat testis compared with 10% NBF and Bouin's fluid and illustrates the importance of establishing the correct fixation conditions for each immunostaining protocol.     

Assessing the accuracy of caries diagnosis via radiograph. Film versus print

BACKGROUND: The authors conducted this study to determine if proximal caries diagnoses made using bitewing radiographic images printed on photographic paper were comparable with diagnoses made using traditional radiographic film images. METHODS: The authors digitized 15 posterior bitewing radiographs that contained 74 carious and 127 sound unrestored proximal surfaces and printed them on photographic paper. Fourteen dentists evaluated the radiographs and two printed image formats (4 x 3 centimeters and 8 x 6 cm) for evidence of caries. The diagnostic accuracy and interobserver agreement for caries diagnoses obtained in the two printed image formats were compared with those for radiographic film images. RESULTS: Overall, the diagnostic accuracy of printed images did not differ significantly from radiographic film images for dentinal caries. However, for caries limited to the enamel surface, a decrease in sensitivity was noted in six of the 14 observers for the smaller print images, while no significant differences in the diagnoses of enamel caries were observed among any of the observers in the enlarged print format. CONCLUSION: This study provides evidence that printed images can be used to diagnose dental caries reliably. CLINICAL IMPLICATIONS: The results of this study indicate that the diagnostic information obtained by viewing printed images is equivalent to that obtained by viewing standard radiographs. Size of the printed image also may be important in caries diagnosis and care must be taken to print bitewing radiographic images at a size that optimizes interpretation. Other factors that must be considered are the type of printer, printer resolution, paper quality and type of ink used. With careful consideration of printing parameters, clinicians can be assured of diagnostic quality in printed images.     

Isolation of glutamate transport-coupled charge flux and estimation of glutamate uptake at the climbing fiber-Purkinje cell synapse

Excitatory amino acid transporters (EAATs) located on neurons and glia are responsible for limiting extracellular glutamate concentrations, but specific contributions made by neuronal and glial EAATs have not been determined. At climbing fiber to Purkinje cell (PC) synapses in cerebellum, a fraction of released glutamate is rapidly bound and inactivated by neuronal EAATs located on postsynaptic PCs. Because transport involves a stoichiometric movement of ions and is electrogenic, postsynaptic currents mediated by EAATs should permit precise calculation of the amount of postsynaptic glutamate uptake. However, this is possible only if a stoichiometric EAAT current can be isolated from all other contaminating signals. We used synaptic stimulation and photolysis of caged glutamate to characterize the current in PCs that is resistant to high concentrations of glutamate receptor antagonists. Some of this response is inhibited by the high-affinity EAAT antagonist TBOA (dl-threo-beta-benzyloxyaspartic acid), whereas the remaining current shows properties inconsistent with glutamate transport. By subtracting this residual non-EAAT current from the response recorded in glutamate receptor antagonists, we have obtained an estimate of postsynaptic uptake near physiological temperature. Analysis of such synaptic EAAT currents suggests that, on average, postsynaptic EAATs take up approximately 1,300,000 glutamate molecules in response to a single climbing fiber action potential.     

A comparison of cytology and fluorescence in situ hybridization for the detection of lung cancer in bronchoscopic specimens

STUDY OBJECTIVES: To determine the relative sensitivity and specificity of cytology and fluorescence in situ hybridization (FISH) for the detection of lung cancer in bronchoscopically obtained specimens. DESIGN: Cytology and FISH were performed on brushing and washing specimens obtained from patients undergoing bronchoscopy for suspected lung cancer. FISH utilized the LAVysion probe set (Abbott Molecular; Des Plaines, IL), which contains locus-specific probes to 5p15, 7p12 (EGFR), 8q24 (C-MYC), and a centromeric probe to chromosome 6. SETTING: Single-center, academic, tertiary medical center. PARTICIPANTS: One hundred thirty-seven patients referred for bronchoscopy for suspicion of lung cancer. INTERVENTIONS: Cytology and FISH were performed on bronchoscopic brushings and washings. MEASUREMENTS AND RESULTS: One hundred thirty-seven patients undergoing bronchoscopy had pathology, FISH, and cytology results. FISH and cytology were performed on 123 washing and 78 brushing specimens. Sensitivities of FISH and cytology were 71% and 51% (p = 0.007), respectively, for brushing specimens, and 49% and 44% (p = 0.541) for washing specimens. When FISH and cytology results were combined, sensitivities were 75% and 61%, respectively, for brushing and washing specimens, which was significantly better (p < 0.001) than cytology alone. Specificities of FISH and cytology for patients with negative findings at the time of initial bronchoscopy were 83% and 100% (p = 0.125), respectively, for brushing specimens, and 95% and 100% (p = 0.500) for washing specimens. CONCLUSIONS: These findings show that FISH is significantly more sensitive than conventional cytology for detecting lung cancer in bronchial brushing specimens; when combined with cytology, FISH can improve the diagnostic sensitivity of detecting malignancy in bronchial brushing and washing specimens.     

Cystitis glandularis

The cytologic finding of glandular cells in a urine specimen is unusual. The differential diagnosis ranges from benign conditions such as cystitis glandularis to adenocarcinoma. Glandular cells of cystitis glandularis with intestinal metaplasia have a bland cytologic appearance. If detected in a urine cytology specimen colonic metaplasia can be reported.