Quetiapine and its metabolite norquetiapine: translation from in vitro pharmacology to in vivo efficacy in rodent models.

BACKGROUND AND PURPOSE: Quetiapine has a range of clinical activity distinct from other atypical antipsychotic drugs, demonstrating efficacy as monotherapy in bipolar depression, major depressive disorder and generalized anxiety disorder. The neuropharmacological mechanisms underlying this clinical profile are not completely understood; however, the major active metabolite, norquetiapine, has been shown to have a distinct in vitro pharmacological profile consistent with a broad therapeutic range and may contribute to the clinical profile of quetiapine. EXPERIMENTAL APPROACH: We evaluated quetiapine and norquetiapine, using in vitro binding and functional assays of targets known to be associated with antidepressant and anxiolytic drug actions and compared these activities with a representative range of established antipsychotics and antidepressants. To determine how the in vitro pharmacological properties translate into in vivo activity, we used preclinical animal models with translational relevance to established antidepressant-like and anxiolytic-like drug action. KEY RESULTS: Norquetiapine had equivalent activity to established antidepressants at the noradrenaline transporter (NET), while quetiapine was inactive. Norquetiapine was active in the mouse forced swimming and rat learned helplessness tests. In in vivo receptor occupancy studies, norquetiapine had significant occupancy at NET at behaviourally relevant doses. Both quetiapine and norquetiapine were agonists at 5-HT1A receptors, and the anxiolytic-like activity of norquetiapine in rat punished responding was blocked by the 5-HT1A antagonist, WAY100635. CONCLUSIONS AND IMPLICATIONS: Quetiapine and norquetiapine have multiple in vitro pharmacological actions, and results from preclinical studies suggest that activity at NET and 5-HT1A receptors contributes to the antidepressant and anxiolytic effects in patients treated with quetiapine.

A mutation in the glycine binding pocket of the N-methyl-D-aspartate receptor NR1 subunit alters agonist efficacy.

Alanine 714 of the NMDA receptor NR1 subunit resides in the glycine binding pocket. The Ala714Leu mutation substantially shifts glycine affinity, but here no effect on antagonism by DCK is detected. Ala714Leu is also found to limit the efficacy of a partial agonist without altering its apparent affinity. The differential sensitivity of Ala714Leu to glycine agonists suggests that alanine 714 may be an intermediary in transducing the ligand binding signal.

Regulation of spvR, the positive regulatory gene of Salmonella plasmid virulence genes.

The regulation of the spvR promoter from the Salmonella dublin virulence plasmid was monitored using promoter-reporter gene fusion constructs. Activity was dependent upon the presence of the spv region and was affected by the number of copies of the spv region present within the cell. Activity remained constant throughout exponential growth, and increased rapidly with the onset of stationary phase, under both aerobic and anaerobic conditions. Additionally, the level of spvR expression was controlled by the availability of iron, activity being greatest under low iron conditions in stationary phase. The spvA gene product negatively regulated spvR expression in a dose-dependent manner, indicating that SpvA provides a negative feedback mechanism for this operon.

Early clinical results: SOUNDTEC implantable hearing device phase II study.

OBJECTIVE: To assess the safety and efficacy of a new semi-implantable electromagnetic hearing device, the SOUNDTEC Direct Drive Hearing System (DDHS), and to compare its performance with that of subjects' previously worn, optimally fit hearing aids. Preliminary results for the first 10 subjects are presented. STUDY DESIGN: The protocol specified in the Investigational Device Exemption is used in this ongoing FDA phase II 100-subject multicenter clinical trial. METHODS: For baseline, each subject is tested wearing his or her own optimally fit hearing aid in the ear to be implanted. Six-month postoperative outcome measures using the SOUNDTEC DDHS are compared with the baseline. Multiple objective and subjective outcomes (as listed under Results) were measured. RESULTS: When compared with the subjects' optimally fit hearing aids, the SOUNDTEC DDHS provided an average improvement of 52% in functional gain (250-6000 Hz), 22% in aided thresholds, 3.8% for speech discrimination in quiet, 17% for speech in noise, 13.1% in articulation index scores, 28% in aided benefit, 27.3% in sound quality of speech, and a 16.7% increase in overall subject satisfaction. In addition, with the SOUNDTEC DDHS, subjects reported absence of acoustic feedback, little or no occlusive effects, and more natural sound perception. CONCLUSION: Analysis of data on the first 10 subjects using the SOUNDTEC DDHS indicates positive outcomes regarding safety and efficacy, although the small sample size is not sufficient to permit valid statistical inferences to be drawn from our preliminary data. Results also demonstrate improvement in performance compared with the subjects' optimally fit hearing aids and an improvement in quality of life as demonstrated by objective and subjective tests and measures.

Safety of outpatient tonsillectomy and adenoidectomy.

Recent changes in reimbursement for tonsillectomy and adenoidectomy have resulted in a large number of these procedures being done on an outpatient basis. There is still considerable controversy, however, as to the safety of this concept. We reviewed the charts of 1000 consecutive patients who underwent these procedures. Three hundred ninety-six procedures were performed as inpatient surgery and 604 were performed as outpatient surgery. Patients were considered as candidates for outpatient surgery if they met specific criteria, such as good overall medical health, no central apnea, normal bleeding history and profile, and had adequate social considerations. The inpatient group included those patients who did not meet the criteria to be outpatients. We compared the complication rates of these two groups with regard to age, type of procedure performed (tonsillectomy, adenoidectomy, adenotonsillectomy), and indication for surgery in order to determine if there was any increased risk of outpatient surgery, despite strict selection criteria. The two groups were similar in their distribution with regards to age, sex, type of procedure, and indication for surgery. The overall complication rate for the entire group was 7.9%, with an 11.8% complication rate for inpatients and 4.1% complications for outpatients. The higher complication rate among the inpatient group is probably a direct result of the selection process because this group included the higher-risk patients. On the basis of these findings, we believe that surgery of the tonsils and adenoids can be performed safely as an outpatient procedure, regardless of age, indication, or procedure, if the candidates for ambulatory surgery are carefully selected by the surgeon.

Accumulation of the p53 tumor-suppressor gene product in oral leukoplakia.

OBJECTIVES: (1) To determine whether the protein of the suppressor gene p53 accumulates in leukoplakia of the oral cavity in individuals who use snuff; and (2) to determine whether a correlation exists between the accumulation of p53 protein and the degree of epithelial dysplasia present in oral leukoplakia. DESIGN: Retrospective analysis of archival tissue specimens. SETTING: The University Hospital, a tertiary referral hospital affiliated with the Oklahoma University Medical Center, Oklahoma City, Oklahoma. PATIENTS: In the first part of the study, biopsy specimens of leukoplakia from 12 persons who used snuff were compared with specimens from uninvolved oral mucosa of the same persons and with biopsy specimens from 12 nontobacco-using persons. In the second part of the study, accumulation of p53 protein was determined in 42 archival paraffin-embedded specimens from oral leukoplakia and correlated with the degree of epithelial dysplasia. METHODS: Accumulation of p53 protein was assessed by immunoperoxidase staining with four different primary antibodies. Positive cells were counted in five consecutive high-power fields. RESULTS: In part one, the average number of positive cells in the leukoplakia of snuff-users (21.89 +/- 4.33; mean +/- SE) was higher than that of normal-appearing mucosa (4.00 +/- 1.0; p < 0.05) and that of nontobacco-using controls (7.00 +/- 5.04). In part two, the average number of positive cells was higher in the moderately dysplastic (140.36 +/- 30.03) and severely dysplastic lesions (232.86 +/- 26.85) than in the mildly dysplastic lesions (14.53 +/- 3.33; p < 0.05). The correlation between the degree of epithelial dysplasia and the number of cells positive is strong (Spearman's correlation coefficient = 0.853). CONCLUSIONS: The accumulation of p53 protein in leukoplakia of snuff-users is higher than in normal-appearing oral mucosa from both snuff-users and nontobacco-using controls. A strong correlation exists between the degree of epithelial dysplasia present in oral leukoplakia and the number of cells staining positive for p53. The accumulation of p53 protein holds potential as an intermediate end point in studies of chemoprevention of oral cancer.

Cerebellar abscesses: a review of seventeen cases.

Seventeen cases of cerebellar abscesses are reviewed. The incidence was 18% of all brain abscesses. Thirteen were males, and four were females. Headache was the most common presenting symptom. These abscesses have a better prognosis for survival and neurological function than supratentorial abscesses. They are less likely to be encapsulated. Continued neurological decline in the face of adequate surgical treatment of a single abscess should alert the physcian to the possibility of a second abscess.

Mass loading on the ossicles and middle ear function.

The middle ear as a levered vibrating system for sound transmission from the external to the inner ear is affected by changes in ossicular chain mass. Mass loading of the ossicles may impair ossicular dynamics and sound transmission to the inner ear. It is incumbent on otologic surgeons and researchers of middle ear mechanics to consider the mass loading effect on middle ear function in clinical and physiological applications. The residual hearing and frequency response can change after surgery or implantation of middle ear prostheses. We conducted experiments on mass loading effects on the middle ear transfer functions by using laser Doppler interferometry and a human temporal bone model. Two implant mass loading conditions were tested on 17 fresh or fresh-frozen temporal bones and compared with the unloaded condition for the frequencies 250 to 8,000 Hz. The results show that the linearity of the middle ear function did not change, although displacement of the stapes footplate decreased after the increased masses were placed on the incudostapedial joint. The greater the mass of the implant, the less displacement was measured at the stapes footplate. We conclude that there is a quantitative limit to increased mass on the ossicular chain above which the mass will remarkably impair hearing thresholds.

Semi-implantable electromagnetic middle ear hearing device for moderate to severe sensorineural hearing loss.

Despite the many improvements in hearing aid technology, conventional hearing aids continue to have significant limitations, which has led to increased interest in implantable hearing devices. The SOUNDTEC Direct Drive Hearing System for moderate to moderately severe sensorineural hearing loss is one such device. In this article the authors present results on five individuals enrolled in a Food And Drug Administration Phase I feasibility study.

The implantable hearing device for sensorineural hearing impairment. The Hough Ear Institute experience.

This article describes one group's experience in developing and implanting rare earth magnets for conductive hearing loss and also for sensorineural hearing loss. Success and failures from over a decade of work are highlighted.

Implantable hearing device performance measured by laser Doppler interferometry.

Recent application of the Doppler principle laser interferometry to audiology, acoustics and otology has facilitated the development of implantable hearing devices (IHDs). During the design and testing of two different electromagnetic middle ear implants for sensorineural hearing loss, we used single-point laser Doppler interferometry (LDI). A commercially available interferometer, internally calibrated and validated against a National Institute for Standards and Technology (NIST) standard, was used with both mechanical fixtures and fresh temporal bones to evaluate implant mass, shape and orientation, attachment, electromagnetic coupling and acoustic properties. At both Hough Ear Institute and Symphonix Devices, Inc., we have shown that high fidelity and amplitudes can be recorded in vitro over a frequency range of 500 Hz to 10 kHz. These data can provide greater assurance of safety and efficacy to regulatory agencies before entering clinical trials. We propose that LDI be considered as an international standard for accurate, consistent comparison of performances of all IHDs during development. Furthermore, the future availability of human IHD data will allow for the extrapolation of a mechanical bench model of the middle ear transfer function for use in quality control during manufacturing and diagnosis of failure in IHDs.

Vaginal microbiota of spayed dogs with or without recurrent urinary tract infections.

BACKGROUND: Limited information is available regarding the vaginal microbiota of normal spayed dogs and spayed dogs with recurrent UTIs. Vaginal lactic acid-producing bacteria (LAB) have been associated with decreased frequency of recurrent urinary tract infection in women and may have a protective role within the urinary tract of female dogs. HYPOTHESIS/OBJECTIVES: Spayed dogs with historical recurrent UTI will have decreased prevalence of LAB and increased prevalence of uropathogenic bacterial populations in the vaginal microbiota when compared with the vaginal microbiota of healthy, spayed dogs. ANIMALS: Twenty-one client-owned adult spayed female dogs with historical recurrent UTI and 23 healthy, spayed female dogs without a history of recurrent UTI. METHODS: Dogs were placed into a recurrent UTI group or control group in this prospective study. Bacterial populations were isolated and characterized from vaginal swabs obtained from each dog. RESULTS: The most common bacterial isolates obtained from the vaginal tract of all dogs were Escherichia coli (11/44) and S. pseudintermedius (13/44). E. coli was isolated from the vaginal tract of 8 of 21 (38%) dogs in the rUTI group and 3 of 23 (13%) dogs in the control group (P = .08). LAB were isolated from 7 of the 44 dogs. Two of these 7 dogs were in the rUTI group and 5 of the 7 dogs were in the control group. CONCLUSIONS AND CLINICAL IMPORTANCE: The vaginal microbiota of spayed female dogs with recurrent UTI was similar to the control population of normal, spayed female dogs.

The effect of an oral probiotic containing lactobacillus, bifidobacterium, and bacillus species on the vaginal microbiota of spayed female dogs.

BACKGROUND: Recurrent urinary tract infections (UTIs) are often difficult to treat. Vaginal colonization with lactic acid-producing bacteria (LAB) is associated with reduced frequency of recurrent UTIs in women. Oral probiotics might help increase the prevalence of vaginal LAB and decrease the frequency of recurrent UTIs in dogs. HYPOTHESIS: Administration of an oral probiotic supplement containing Lactobacillus, Bifidobacterium, and Bacillus species will increase the prevalence of LAB in the vagina of dogs. ANIMALS: Thirty-five healthy, spayed female dogs without history of recurrent UTIs. METHODS: Prospective, controlled study. Enrolled dogs received an oral probiotic supplement for 14 or 28 days. A vaginal tract culture was obtained from each dog before and after oral probiotic administration. Twenty-three dogs received the oral probiotic supplement daily for a period of 14 days and 12 dogs received the oral probiotic supplement daily for a period of 28 days. RESULTS: Lactic acid-producing bacteria were isolated from 7 of 35 dogs prior to probiotic administration. After the treatment course, 6 of 35 dogs had LAB isolated. Only one of these dogs had LAB (Enterococcus canintestini) isolated for the first time. Enterococcus canintestini was the most common LAB isolated from all dogs in this study, although it was not included in the probiotic supplement. CONCLUSIONS AND CLINICAL IMPORTANCE: Lactic acid-producing bacteria are not a common isolate from the vaginal vault of dogs. Administration of this oral probiotic supplement for a 2- or 4-week period did not increase the prevalence of vaginal LAB in dogs.

Uropathogenic E. coli promote a paracellular urothelial barrier defect characterized by altered tight junction integrity, epithelial cell sloughing and cytokine release.

The urinary bladder is a common site of bacterial infection with a majority of cases attributed to uropathogenic Escherichia coli. Sequelae of urinary tract infections (UTIs) include the loss of urothelial barrier function and subsequent clinical morbidity secondary to the permeation of urine potassium, urea and ammonia into the subepithelium. To date there has been limited research describing the mechanism by which this urothelial permeability defect develops. The present study models acute uropathogenic E. coli infection in vitro using intact canine bladder mucosa mounted in Ussing chambers to determine whether infection induces primarily a transcellular or paracellular permeability defect. The Ussing chamber sustains tissue viability while physically separating submucosal and lumen influences, so this model is ideal for quantitative measurement of transepithelial electrical resistance (TER) to assess alterations of urothelial barrier function. Using this model, changes in both tissue ultrastructure and TER indicated that uropathogenic E. coli infection promotes a paracellular permeability defect associated with the failure of umbrella cell tight junction formation and umbrella cell sloughing. In addition, bacterial interaction with the urothelium promoted secretion of cytokines from the urinary bladder with bioactivity capable of modulating epithelial barrier function including tumour necrosis factor-α, interleukin (IL)-6 and IL-15. IL-15 secretion by the infected bladder mucosa is a novel finding and, because IL-15 plays key roles in reconstitution of tight junction function in damaged intestine, this study points to a potential role for IL-15 in UTI-induced urothelial injury.

Immediate decline in DNA synthesis in neonatal rat lung caused by exposure to 100% oxygen.

Oxygen therapy in preterm infants is associated with bronchopulmonary dysplasia, but the relative importance of oxygen toxicity as compared to adverse effects of intubation and mechanical ventilation, remains uncertain. In freely-breathing neonatal rats, exposure to 100% oxygen for as little as 2 hr produced a significant reduction in lung DNA synthesis, evaluated by [3H]thymidine incorporation, without a concomitant effect on [3H]leucine incorporation into protein. These results indicate that hyperoxia has a selective deleterious effect on mitosis in developing lung.

Development of a probe and PCR primers specific to the virulence plasmid of Salmonella enteritidis.

Restriction analysis of the Salmonella enteritidis virulence plasmid, followed by hybridisation with radiolabelled S. typhimurium and S. dublin plasmids, revealed a 2-kb Pstl/Bg/l fragment that was specific to S. enteritidis. Colony hybridisation experiments with this fragment detected 29 out of 31 S. enteritidis strains tested. S. blegdam, S. moscow and S. paratyphi C also hybridised with this fragment and a comparison of the plasmids from these serotypes revealed striking similarities. A Pstl/Pvull sub-clone of the 2-kb fragment was used to design primers for quantitative polymerase chain reaction (QPCR) detection of S. enteritidis from broth culture.

An alanine residue in the M3-M4 linker lines the glycine binding pocket of the N-methyl-D-aspartate receptor.

While attempting to map a central region in the M3-M4 linker of the N-methyl-D-aspartate receptor NR1 subunit, we found that mutation of a single position, Ala-714, greatly reduced the apparent affinity for glycine. Proximal N-glycosylation localized this region to the extracellular space. Glycine affinities of additional Ala-714 mutations correlated with side chain volume. Substitution of alanine 714 with cysteine did not alter glycine sensitivity, although this mutant was rapidly inhibited by dithionitrobenzoate. Glycine protected the A714C mutant from modification by dithionitrobenzoate, whereas the co-agonist L-glutamate was ineffective. These experiments place Ala-714 in the glycine binding pocket of the N-methyl-D-aspartate receptor, a determination not predicted by previous structural models based on bacterial periplasmic binding protein homology.

The 5'-untranslated region of the N-methyl-D-aspartate receptor NR2A subunit controls efficiency of translation.

The N-methyl-D-aspartate (NMDA) receptor plays a central role in such phenomena as long term potentiation and excitotoxicity. This importance in defining both function and viability suggests that neurons must carefully control their expression of NMDA receptors. Whereas the NR1 subunit of the NMDA receptor is ubiquitously transcribed throughout the brain, transcription of NR2 subunits is spatially and temporally controlled. Since heteromeric assembly of both subunits is required for efficient functional expression, post-transcriptional modification of either subunit would affect NMDA receptor activity. Here it is demonstrated that the 5'-untranslated region (5'-UTR) of the NR2A subunit severely restricts its protein translation in both Xenopus oocytes and in an in vitro translation system. Mutational analysis of the 5'-UTR implicates secondary structure as the major translational impediment, while the five alternate start codons play minor roles. An important biological role for the 5'-UTR of NR2A is further suggested by the unusually high level of sequence conservation between species. In contrast, the 5'-UTR of NR1 does not inhibit translation and is not consrved. Taken together, these findings suggest a mechanism for modulation of NMDA receptor activity through the control of translational efficiency of a single subunit.