In vivo 19F-NMR study of isoflurane elimination from brain.

The time course of isoflurane elimination from rabbit brain was studied in vivo with 19F-NMR spectroscopy. Two exponential decay functions with different time constants were observed and assigned to two distinct brain compartments. Isoflurane has a 26 min time constant for one compartment (similar to a value of 25 min with halothane) but 174 min in the second one, compared with 320 min for halothane. The shorter half-life for isoflurane may be due to lower solubility of this agent in brain tissue. Comparison of isoflurane 19F chemical shifts in solvents in isolated brain lipids and in whole brain tissue indicates that the anesthetic present in the brain exists in a single environment (on the NMR time scale), which is a weighted average of both hydrophilic and hydrophobic environments.

In vivo 19F-NMR study of halothane distribution in brain.

Halothane distribution and elimination from rabbit brain was studied in vivo using 19F-NMR spectroscopy. Two exponential decay functions for the anesthetic were observed in the clearance curve. They are assigned to halothane in brain held in two distinct chemical environments characterized by different chemical shifts, and half-lives (25 and 320 min). A nonvolatile halothane metabolite with a half-life of several days was found to be present in rabbit brains. The in vivo results were corroborated by ex vivo experiments on excised brain tissue. Halothane was distributed in all of the major cell subfractions, whereas the metabolite was present predominantly in the cytoplasm.

Immunochromatographic measurement of phenobarbital in whole blood with a non-instrumented assay.

We tested the precision and accuracy of the AccuLevel Phenobarbital Test, which reports whole-blood (fingerstick) results in plasma equivalent values, and compared these values with plasma results obtained using established methods. We conclude that the assay is precise, reliable, accurate for single tests, and is appropriate for use in offices, outpatient settings, and emergency rooms.

Determination of halothane distribution in the rat head using 19F NMR technique.

The distribution of halothane in the rat head was examined with 19F NMR rotating-frame zuegmatography and 2DFT 19F NMR imaging. The rotating frame experiments were conducted at varying times following anesthesia to assess the time dependence of the halothane distribution. The results of these experiments demonstrate that halothane and halothane metabolite are unequally partitioned through the rat tissues examined. 19F spin-echo imaging experiments were conducted immediately following anesthesia. The results of these experiments are compared with those of the spectroscopic technique.

Noninvasive in vivo demonstration of 2-fluoro-2-deoxy-D-glucose metabolism beyond the hexokinase reaction in rat brain by 19F nuclear magnetic resonance spectroscopy.

The metabolism of 2-fluoro-2-deoxy-D-glucose (FDG) in vivo was observed noninvasively in rat brain using 19F nuclear magnetic resonance (NMR) spectroscopy following an intravenous injection of FDG (400 mg/kg). At 3 h after infusion, four resonances with discrete chemical shifts were resolved. Chemical shift analysis of these resonances suggested the chemical identity of two of the resonances to be FDG and/or FDG-6-phosphate and 2-fluoro-2-deoxy-delta-phosphogluconolactone and/or 2-fluoro-2-deoxy-6-phosphogluconate. The chemical identities of the other two resonances remain to be elucidated. The present study indicates that the metabolism of FDG in vivo is more extensive than is previously recognized and demonstrates the feasibility of using 19F NMR spectroscopy to follow the 19F-containing metabolites of FDG in vivo.

New NMR probe designs for neonatal, immature and adult heart research. With a brief review.

We present three new radiofrequency probes for nuclear magnetic resonance (NMR) research with perfused rabbit hearts at different maturational ages. The objective of the double-tunable, cylindrical-window probe design was to achieve a highly homogeneous magnetic field throughout the 16, 25 or 30 mm diameter usable volume for consistency of comparison of measurements obtained from neonate, immature and adult rabbit hearts, respectively. This probe design tunes to 23-Sodium for rapid shimming and then, to 31-Phosphorus for measurements of pH and high energy phosphate metabolites. All three probes yielded excellent signal-to-noise ratios and radiofrequency operating characteristics. We introduce these new probes here in the context of a brief review of other state-of-the-art designs for in vitro and in vivo cardiovascular research.

An empirical study of the DSM-IV Defensive Functioning Scale in personality disordered patients.

The inclusion of the Defensive Functioning Scale (DFS) in the DSM-IV provides clinicians with the opportunity to incorporate psychodynamic information into their descriptive diagnoses. The DFS contains 27 specific defenses covering six levels of defensive functioning ranging from psychotic to normal. This study undertook an initial empirical evaluation of the DFS. A sample of 100 clinicians completed a questionnaire containing both the personality disorder (PD) symptoms and the DFS defenses of PD patients known to them, DFS ratings were not related to clinician orientation. Patient gender was related to only one defense level, with women being assigned significantly more action level defenses than men. Multiple regression analyses revealed unique and meaningful patterns of association between the defense levels and PD symptoms. Additionally, the DFS ratings provided unique information regarding level of impairment and treatment success. These results provide initial empirical support for the clinical application and relevance of the proposed DFS system.

A Rorschach exploration of the DSM-IV Borderline Personality Disorder.

Rorschach data has been useful in identifying the DSM Borderline Personality Disorder (BPD) and has potential for improving our understanding of this disorder. Recently, the DSM-IV BPD has been shown to be composed of 3 primary or core factors: Factor I-unstable self-other images. Factor II-deficits in affect and thought modulation, and Factor III-impulsive self-damaging actions. In a sample of outpatients with personality disorders. we explored the relationships among 6 psychoanalytically derived Rorschach scales (primitive aggression, oral dependency, self-other differentiation, splitting, devaluation, and projective identification), and the core BPD features. Significant correlations were found between 5 of the Rorschach variables and BPD total scores. Correlations between these 5 variables and the BPD core features showed that oral dependency needs were negatively associated with all 3 BPD core features, whereas the defenses of devaluation and splitting were positively associated with these core features. The clinical implications of these findings are reviewed.

31P surface-coil NMR analysis of metabolic status in KHJJ tumors.

Noninvasive monitoring of the effects of treatment on cancer tissue is fundamental to the development of rational radioimmunotherapy (RIT) schemes employing radiolabeled monoclonal antibodies or antibody fragments specific for human cancer. Recent advances in nuclear magnetic resonance spectroscopy make it an attractive candidate for sequential, topical monitoring by 31P NMR of metabolic events during RIT. Preliminary to this effort, we examined the metabolic competence of the well-characterized, murine KHJJ tumor in situ in BALB/c mice using 31P surface-coil NMR. The ATP/Pi ratio in tumor volumes ranging from 100 to 800 mm3 showed that tumors over this range of sizes were able to maintain high levels of ATP relative to Pi. As the tumor volume increased above 1 cm3, ATP/Pi levels indicated poor metabolic competence. This lack of metabolic competence was correlated with histological evidence of tissue necrosis and vascular disintegration. The T1 values of assigned phosphorus metabolites were established. Intracellular pH, as determined from the chemical shift of Pi, was found to vary in these tumors from 7.1 in rapidly metabolizing tissue to 6.6 in necrotic tumors.