Conformational changes in the negative arm of the circadian clock correlate with dynamic interactomes involved in post-transcriptional regulation

Biology is tuned to the Earth's diurnal cycle by the circadian clock, a transcriptional/translational negative feedback loop that regulates physiology via transcriptional activation and other post-transcriptional mechanisms. We hypothesize that circadian post-transcriptional regulation might stem from conformational shifts in the intrinsically disordered proteins that comprise the negative arm of the feedback loop to coordinate variation in negative-arm-centered macromolecular complexes. This work demonstrates temporal conformational fluidity in the negative arm that correlates with 24-h variation in physiologically diverse macromolecular complex components in eukaryotic clock proteins. Short linear motifs on the negative-arm proteins that correspond with the interactors localized to disordered regions and known temporal phosphorylation sites suggesting changes in these macromolecular complexes could be due to conformational changes imparted by the temporal phospho-state. Interactors that oscillate in the macromolecular complexes over circadian time correlate with post-transcriptionally regulated proteins, highlighting how time-of-day variation in the negative-arm protein complexes may tune cellular physiology.

The Graduate Record Examination as an admission requirement for the graduate nursing program

The use of the Graduate Record Examination (GRE) as an admission criterion for the master's degree program was evaluated using data from student records of the population that graduated or dropped out of the State University of New York at Buffalo program between 1983 and 1992. The GRE correlated with first-year and overall graduate grade point averages, but it was a weaker predictor of performance than was the undergraduate grade point average. These findings are discussed in light of the negative consequences of using the GRE related to the recruitment of minority students, women, and older students.

CT in the preoperative assessment of the mandible and maxilla for endosseous implant surgery. Work in progress

A new computer software program that generates panoramic and oblique computed tomography scans was used to examine 205 patients who were being considered for endosseous dental implants in the mandibular or maxillary arches. This technique allowed recognition of the course of the inferior alveolar nerve canal and measurement of the alveolar ridge, which facilitated the design and placement of an optimal dental prosthesis.

Locally Optimal Run-Length Compression Applied to CT Images

Run-length data compression techniques are described that preserve image content. After decompression, images are restored to their original state without loss in image gray scale or resolution. The first technique introduces terminology and illustrates a simple method for efficient picture archiving. It demonstrates the principle of run-length techniques. A second more general approach encodes picture information in a manner that adapts to local variation in pixel standard deviation. Among several options of compression formats, the one that delivers the best local compression is selected. Results of our compression techniques are given for several hundred computed tomography (CT) pictures with comparison to image entropy measures. A general solution to the optimal run-length compression of digital data is outlined. Routine application of the locally optimal method is also described.

Computed tomography of the spine: curved coronal reformations from serial images

A new imaging format described here uses nonplanar reformations that follow the contour of curved structures intersected by a series of regularly spaced CT scans. The CT scanning procedure is described, and algorithmic details of this new format are presented. A standard set of reformatted images is suggested, and clinical examples are given to illustrate the diagnostic value of this new format.

Data compression techniques for CT image archiving

Large digital files are inherent to computed tomography (CT) image data. The CT installations that routinely archive patient data are penalized computer time, technologist's time, tape, purchase, and file space. This paper introduces compression techniques that reduce the amount of tape needed to store image data and the amount of computer time to do so. The benefits delivered by this technique have also been applied to CT disk systems in which limited on-line memory requires compact file storage. Typical reductions of 40 to 50% of original file space are reported.

Theophylline elimination in the pregnant and fetal rabbit

Aminophylline and theophylline are commonly used to treat asthma. We studied theophylline pharmacokinetics in the pregnant and nonpregnant rabbit as well as in the intrauterine and extrauterine fetus. The t1/2 was increased (p less than 0.05) and the clearance was decreased (p less than 0.05) in the pregnant compared to the nonpregnant rabbit. The t1/2 of theophylline in the newborn rabbit was 43.5 +/- 12.0 hr, approximately 15 times longer than in the nonpregnant rabbit. Twenty-four hours after a 20 min maternal aminophylline infusion, both the intrauterine fetus and maternal serum theophylline concentrations were very similar. The transplacental transfer from the maternal to fetal circulation occurred in less than 1 hr. The maternal to fetal serum ratios for theophylline were similar after a 5-day maternal aminophylline infusion (ratio 1.22 +/- 0.20) or after a 20 min infusion (ratio 1.24 +/- 0.20). Our findings indicate that the newborn rabbit eliminates theophylline very slowly, and maternal aminophylline or theophylline therapy that would result in high peak serum concentrations in the fetus, particularly just before birth, should be avoided.

Pulmonary superoxide dismutase activity in the euthyroid and hypothyroid ovine fetus

Pulmonary superoxide dismutase (SOD) activity was measured in 11 euthyroid and 15 hypothyroid ovine fetuses at 130 days gestation. In the euthyroid fetus, the mean pulmonary SOD activity was similar in saline- and thyroxine-infused groups. Compared to the euthyroid fetus, the mean pulmonary SOD activity was significantly lower in the noninfused or saline-infused athyrotic fetus. Administration of thyroxine to the hypothyroid fetus results in a normalization of pulmonary SOD activity to control values. Thus, thyroxine appears to influence the maturation of pulmonary SOD activity in the ovine fetus during the third trimester.

Stereotactic neurosurgery using 3-D image data from computed tomography

During the last decade computer tomography (CT) scanners have provided images that show internal anatomy of unsurpassed resolution and that, since they are inherently digital, a format computer graphics software can easily process. By combining CT images, a specially designed head-mounted instrument, and the software to coordinate them, improved surgical accuracy can result for stereotactic surgery. Using the head-mounted frame and the interactive computer software described here, the entire stereotactic approach is transportable to computer systems of three major CT manufacturers. Neurosurgeons now have a tool that allows trajectory selection and probe placement entirely within the CT suite. Compared with conventional stereotaxis, the CT-aided approach offers increased accuracy, with a significant fluid contrast injection for finding reference points and the avoidance of important brain structures due to the direct visualization afforded with CT. Key interactive features are shown here that allow unrestricted views of anatomy in the area of surgical interest. For example, oblique views that are normal to the trajectory of neurosurgical instruments are extracted in real time during the surgical procedure. Standard sagittal (lateral) and coronal (frontal) image planes are also shown integrated with the interactive technique. The surgical procedure is outlined and details of the pattern recognition technique for image-to-frame registration are presented. Test, phantom, and patient results are given.

Extracting oblique planes from serial CT sections

Although geometric principles describing planes oblique to an orthogonal image data set are well understood, no implementation has been offered for their practical specification, extraction, and display in a clinical environment. Fast image generation and ease of user specification-requisite credentials for successful clinical implementations-are handicapped by the large volume of data to process. Other difficulties further complicate an interactive solution. Once oblique planes are generated, their orientation is often difficult to perceive without visual cues that aid their registration with standard image formats. In addition, Moire patterns introduced by digital aliasing often currupt resultant views. In this paper, techniques are outlined for simplifying oblique plane specification, a methodology is presented for image construction, and an interactive approach is illustrated to register images for such general view planes. Finally, digital aliasing of oblique planes is discussed, and a solution is given for this application.

Relationship between arterial and venous bicarbonate values

We determined the clinical efficacy of using the venous CO2 value, as obtained with routine "electrolytes", in acid-base management. Venipuncture samples for venous CO2 content and chloride concentrations were obtained in 336 patients with arterial blood pH, PaO2, PaCO2, and oxygen saturation determinations. The linear correlation between actual calculated arterial HCO3- and the measured venous CO2 was significant (P less than .001). Using venous CO2, chloride, and arterial pH values, we present various prediction equations for estimating arterial HCO3-. We determined the effects of time delay, exposure to air, and acute changes in arterial blood pH and PaCO2 on venous CO2 levels. Venous CO2 determinations should not be substituted for the arterial HCO3 value in the Henderson-Hasselbalch equation to calculate arterial blood pH or PaCO2. Clinically, the venous CO2 value has little direct use, but when venous CO2 content is abnormal, it should alert the clinician to the need for obtaining arterial blood gas and pH values.

Chronic intravenous infusion in the rat: a nonsurgical approach

A rapid, simplified technique of intravenous catheterization of the unanesthetized rat was developed for continuous infusion. A 19-gauge thin-walled needle was inserted percutaneously into the dilated tail vein, and polyethylene tubing was advanced through the needle into the vein. The catheter was protected by wire mesh electrical sheathing taped securely to the tail. This approach eliminated the need for anesthesia and surgery which were traumatic to the animal and time consuming for the investigator. This method was used successfully in 32 rats given continous infusion for up to 5 days.

Organization and access of image data by areas

This paper concerns methods for indexing areas in twodimensional array data. A method for naming subpictures from rasterscan image data is presented with notation that eases their subsequent storage access. Equations are given for converting each subpicture name into a storage-location pointer. A function ``NUMERIC'' is described that aids this task. Algorithms enabling efficient retrieval of subpicture areas from sequential and direct access files are presented. Examples are given that show that improved retrieval response is possible from using NUMERIC to sort lists of areas to be recalled. The paper includes an overview of tree data structures, the subject implemented by these techniques. An overlapping picture subareas storage scheme is discussed.

An effect of paraquat on the lungs of rabbits. Its implications in smoking contaminated marihuana

Thirty-six rabbits received the herbicide, paraquat (1,1'-dimethyl-4,4'-dipyridylium dichloride), by selective intrabronchial instillation in doses ranging from 0.1 gm to 1 pg. Sixteen additional rabbits were given paraquat dichloride (25 mg/kg of body weight) intraperitoneally, subcutaneously, intravenously, or orally. The lung of the rabbit proved to be highly sensitive to paraquat administered by intrabronchial deposition, moderately sensitive to intravenously administered paraquat, and resistant to the chemical when given intraperitoneally or subcutaneously. One picogram of paraquat dichloride delivered by bronchial catheter produced a 1.0-mm pulmonary lesion consisting of focal hemorrhage, congestion of capillaries, intra-alveolar macrophages, and moderate thickening of the alveolar septa. This finding suggests that pulmonary damage could potentially result from smoking marihuana that has been sprayed with paraquat.

Hypoxic protection in paraquat poisoning

Ingestion or injection of the herbicide paraquat (1,1'-dimethyl-4,4'-dipyridylium dichloride) has caused more than 120 deaths in humans. Most have been due to respiratory failure caused by pulmonary edema, hemorrhage, and atelectasis, or subsequent pulmonary fibrosis. Paraquat is concentrated in lung tissue and is believed to cause superoxide radical formation in the presence of oxygen and suitable electron donors. Exposure to increased concentrations of oxygen has been reported to accelerate the toxicity of paraquat. The therapeutic efficacy of a reduced oxygen environment was investigated by exposing paraquat-poisoned mice to 10% oxygen after stepwise drops from 14% oxygen. Sixty-one mice were given intraperitoneal injections of 27 mg. per kg. of paraquat. The 25 mice in hypoxia for 7 days had a 32% mortality rate versus a 78% mortality rate for the remainder of the mice in room air, p less than 0.01. After a dose of 20 mg. per kg. of paraquat administered intraperitoneally, 24 mice in hypoxia had a 25% mortality rate versus 51% for 35 animals in room air. Brief exposures of the hypoxic group to "normoxia" (room air) led to pulmonary edema and death. The continuous exposure of paraquat-poisoned animals to hypoxic environments was protective. This approach may be useful in other oxidant lung injuries.

Transbronchial biopsy via flexible fiberoptic bronchoscope; results in 164 patients

The diagnostic accuracy and complication rate of transbronchial forceps lung biopsy combined with bronchial brushing were analyzed in 164 consecutive patients, of whom 95 had nonmalignant disease and 51 had malignant disease. Eighteen patients with abnormal chest radiographs had normal transbronchial forceps lung biopsies and no established diagnosis. Satisfactory specimens were obtained in 153 patients (93 per cent), with diagnositc accuracies of 62, 64, and 67 per cent, respectively, in infectious, interstitial, and malignant lung disease. The over-all diagnostic accuracy was 57 per cent. Seven patients were diagnosed as having metastatic carcinoma to the lung by transbronchial forceps lung biopsy, but brush biopsy was psoitive in only 3. Of the 23 patients with primary lung carcinoma diagnosed by transbronchial forceps lung biopsy, 21 had positive brush biopsies. An additional 3 patients with bronchogenic carcinoma, however, were diagnosed only by brush biopsy. Fluoroscopy was essential for accurate positioning of the biopsy instrument. Increased risk factors were present in 83 patients (51 per cent), among whom the immunosuppressed group presented special problems. Significant bleeding in 15 patients (9 per cent) was controlled by conservative management. Pneumothorax occurred in 7 patients (4 per cent). There were no deaths. Transbronchial forceps lung biopsy in experienced hands is safe and well tolerated. The physician, nevertheless, must be prepared to handle major complications, especially bleeding. The procedure has a resonable diagnostic yield in high-risk patients who have a variety of lung lesions.

Light and immunofluorescent study of the Arthus reaction in the rabbit lung

A localized Arthus reaction was produced in the lung of sensitized rabbits by delivery of antigen into a lower lobe bronchus using a method of selective bronchial catheterization under fluoroscopy. The rabbits were sensitized with bovine immunoglobulin G (B-IgG) in incomplete Freund's adjuvant (IFA) to produce precipitating antibody without classic delayed hypersensitivity. Pulmonary histopathology was studied at intervals following antigen challenge, using light and immunofluorescent microscopy. Gross lesions peripheral to the lower lobe bronchus receiving antigen were found within 12 hr. Subsequent necrosis resulted in a dense scar by 6 wk. Microscopically, early lesions were typified by localized bronchitis, bronchiolitis, alveolitis, and vasculitis with exuberant exudates containing predominantly polymorphonuclear leukocytes. Extensive focal necrosis was present by 72 hr. Immunofluorescent studies revealed the presence of B-IgG, rabbit IgG, and complement (C3) in and around bronchi, bronchioles, alveoli, and vessels. No granulomatous lesions were found, and proliferation of alveolar lining cells was not detected in these studies. Thus, the lung can participate in an acute Arthus reaction following local antigen challenge in systemically sensitized animals. The pathology more closely resembles a necrotizing bacterial pneumonia than an interstitial or hypersensitivity pneumonitis under the conditions of this experimental system. Implications for human disease are speculative.

Foreign body removal: a new role for the fiberoptic bronchoscope

Artificial and animal lung models initially were used to investigate the removal of foreign bodies from the tracheobronchial tree with the flexible fiberoptic bronchoscope. Different extraction instruments (claw, basket, forceps, and balloon catheter) were passed separately through the channel of the bronchofiberscope, and tested for usefulness prior to human application. The Fogarty balloon catheter served as a valuable aid in dislodging impacted objects so that the operator could then grasp them with the claw, basket or forceps. The wire claw recovered many of the metallic and organic objects, the wire basket was successful in retrieving only the bulky objects and the forceps (ACMI) was effective in capturing all of the metallic foreign bodies. These techniques, developed in our laboratory, are now being used to augment rigid bronchoscopy in the removal of foreign bodies from adults and older children. At the present time fiberoptic foreign body removal is not recommended for pediatric cases because of the small diameter of the trachea and glottis in infants and young children.