Examining the Role of Microbiota in Emotional Behavior: Antibiotic Treatment Exacerbates Anxiety in High Anxiety-Prone Male Rats.

Intestinal microbiota are essential for healthy gastrointestinal function and also broadly influence brain function and behavior, in part, through changes in immune function. Gastrointestinal disorders are highly comorbid with psychiatric disorders, although biological mechanisms linking these disorders are poorly understood. The present study utilized rats bred for distinct emotional behavior phenotypes to examine relationships between emotionality, the microbiome, and immune markers. Prior work showed that Low Novelty Responder (LR) rats exhibit high levels of anxiety- and depression-related behaviors as well as myriad neurobiological differences compared to High Novelty Responders (HRs). Here, we hypothesized that the divergent HR/LR phenotypes are accompanied by changes in fecal microbiome composition. We used next-generation sequencing to assess the HR/LR microbiomes and then treated adult HR/LR males with an antibiotic cocktail to test whether it altered behavior. Given known connections between the microbiome and immune system, we also analyzed circulating cytokines and metabolic factors to determine relationships between peripheral immune markers, gut microbiome components, and behavioral measures. There were no baseline HR/LR microbiome differences, and antibiotic treatment disrupted the microbiome in both HR and LR rats. Antibiotic treatment exacerbated aspects of HR/LR behavior, increasing LRs' already high levels of anxiety-like behavior while reducing passive stress coping in both strains. Our results highlight the importance of an individual's phenotype to their response to antibiotics, contributing to the understanding of the complex interplay between gut microbes, immune function, and an individual's emotional phenotype.

Subclavian hemodialysis catheter infections: a prospective, randomized trial of an attachable silver-impregnated cuff for prevention of catheter-related infections.

OBJECTIVE: To determine if an attachable silver-impregnated cuff is effective in reducing subclavian hemodialysis catheter-related infections. DESIGN: Prospective, randomized, nonblinded study. SETTING: Community teaching hospital. PATIENTS: One hundred one acute and chronic renal failure patients requiring subclavian venipuncture and catheterization. After randomization, 47 patients underwent subclavian catheterization with a silver-impregnated cuff (Ag-CC), and 54 patients had routine catheter (RC) placements. MEASUREMENTS: Multiple presumed predictor variables for catheter-related infections, exit site infection rate, bacteremia rates, and semiquantitative cultures of all catheters.

Image reconstruction of the interior of bodies that diffuse radiation.

A method for reconstructing images from projections is described. The unique aspect of the procedure is that the reconstruction of the internal structure can be carried out for objects that diffuse the incident radiation. The method may be used with photons, phonons, neutrons, and many other kinds of radiation. The procedure has applications to medical imaging, industrial imaging, and geophysical imaging.

Ruptured aneurysm in pregnancy.

Within the last ten years, twenty pregnant women with ruptured intracranial aneurysms were managed at Los Angeles County-University of Southern California Medical Center. Difficulties encountered in the care of these patients will be illustrated with case studies. In two patients, failure to diagnose subarachnoid hemorrhage delayed management. In another patient, cerebral vasospasm complicated the course. Selection of appropriate diagnostic tests, timing of surgery, importance of fetal monitoring, and method of delivery will be discussed.

Idiopathic acute interstitial nephritis: characterization of the infiltrating cells in the renal interstitium as T helper lymphocytes.

A previously healthy 39-year-old man presented with acute renal failure. There was no history of exposure to drugs nor was there any infection. Renal biopsy revealed interstitial nephritis with extensive acute degenerative changes in the tubules and extensive interstitial infiltration with mononuclear cells and no eosinophils. Monoclonal antibody staining studies identified the cells in the renal interstitium to be a helper/inducer subset of T lymphocytes. We suggest that a delayed hypersensitivity mechanism played a pathogenetic role in this patient's idiopathic acute interstitial nephritis.

Nuclear magnetic resonance blood flow measurements in the human brain.

Timed sequences of nuclear magnetic resonance imaging signals in the human head were used to quantitatively measure blood flow in the internal jugular veins. The procedure can be straightforwardly applied to any vein or artery in the body.

Experimental transmission of Chlamydia psittaci to turkeys from wild birds.

Wild birds were inoculated with Chlamydia psittaci to determine species that could be potential hosts and vectors in transmitting the agent to domestic turkeys. Infection occurred in turkeys exposed to starlings (Sturnus vulgaris), common grackles (Quiscalus quiscula), brown-headed cowbirds (Molothrus ater), and Inca doves (Cardafella inca). Mourning doves (Zenaidura macroura) shed the agent sparingly, but turkeys exposed to them did not become infected, These findings and knowledge of the habits of these various species are discussed. It was concluded that the Inca dove should be considered a potential source of turkey chlamydiosis in Texas. The species studied and other species not studied should be included in serologic surveys and surveillance studies attempting isolation of chlamydiae.

Low-frequency white noise generators for biomedical systems.

There is a need for electronic noise sources for investigation of biological and medical research equipment. Such sources need to provide a "white noise" output with a frequency spectrum flat from one to one hundred Hertz. The present paper describes two designs of such sources. The spectra are measured and compared. One course is the reverse-biased junction of a transistor base-emitter junction operating in the avalanche mode. The second source is a MOS IC pseudo-random digital signal. In both cases, the spectra are presented. The choice between the two sources depends upon the application. For most applications, either source is shown to be satisfactory.

Tomographic imaging with nuclear magnetic resonance.

A technique is described for obtaining tomographic images of hydrogen distribution in animals using nuclear magnetic resonance (NMR). Resonant frequency is proportional to magnetic field strength, so that spatial resolution is achieved by frequency selection and magnetic field shaping. The results of scanning a phantom and two rats are presented.

Loudness Discrimination Index (LDI): a test for the early detection of noise susceptible individuals.

Work has been completed at the Environmental Acoustics Laboratory during the past year on developing an industrially feasible Loudness Discrimination Index (LDI) Test. Data obtained on experimental subjects who had been exposed to brief, high-level sound showed that the maximum Loudness Discrimination Index Shift (LDIS-Max.) is a valid and reliable indicator of temporary, noise-induced, hearing change. This test is better suited to industrial usage than the traditional TTS test. Suggestions for the implementation of LDI testing in the industrial setting are discussed.

The effect of high level sound exposure on the loudness difference limen.

Currently used threshold audiograms fail to detect the early stages of noise-induced hearing impairment. Threshold shifts may reach 10 to 15 dB before the impairment is detected. Loudness difference limen and critical band phenomena may provide an earlier and more sensitive test for such hearing impairment. Data is reported which shows that the difference limen shift (DLS) due to noise persists longer than temporary threshold shift (TTS). These findings suggest that DLS may be a more feasible tool for industrial use than either TTS or monitoring audiometry.

Blood velocity measurements in intact subjects.

Venous blood velocities in intact human forearms can be measured by the use of nuclear magnetic resonance techniques. In essence, two separated coils are placed over the vein, and the arm is held in a magnetic field. Radio-frequency energy in one coil "flips" over the protons in the blood stream, and the second coil detects the arrival of the "flipped" protons. Human blood in vivo and in vitro has a nominal nuclear magnetic resonance relaxation time of 0.4 second.