Safety and Management of Implanted Epilepsy Devices for Imaging and Surgery.

Permanently implanted devices that deliver electrical stimulation are increasingly used to treat patients with drug-resistant epilepsy. Primary care physicians, neurologists, and epilepsy clinicians may encounter patients with a variety of implanted neuromodulation devices in the course of clinical care. Due to the rapidly changing landscape of available epilepsy-related neurostimulators, there may be uncertainty related to how these devices should be handled during imaging procedures and perioperative care. We review the safety and management of epilepsy-related implanted neurostimulators that may be encountered during imaging and surgery. We provide a summary of approved device labeling and recommendations for the practical management of these devices to help guide clinicians as they care for patients treated with bioelectronic medicine.

Desorption kinetics of ciprofloxacin in municipal biosolids determined by diffusion gradient in thin films.

Ciprofloxacin (CIP) is a commonly-prescribed antibiotic that is largely excreted by the body, and is often found at elevated concentrations in treated sewage sludge (biosolids) at municipal wastewater treatment plants. When biosolids are applied to soils, they could release CIP to surface runoff, which could adversely affect growth of aquatic organisms that inhabit receiving water bodies. The hazard risk largely depends on the amount of antibiotic in the solid phase that can be released to solution (labile CIP), its diffusion coefficient, and sorption/desorption exchange rates in biosolids particles. In this study, these processes were evaluated in a Class A Exceptional Quality Biosolids using a diffusion gradient in thin films (DGT) sampler that continuously removed CIP from solution, which induced desorption and diffusion in biosolids. Mass accumulation of antibiotic in the sampler over time was fit by a diffusion transport and exchange model available in the software tool 2D-DIFS to derive the distribution coefficient of labile CIP (Kdl) and sorption/desorption rate constants in the biosolids. The Kdl was 13 mL g-1, which equated to 16% of total CIP in the labile pool. Although the proportion of labile CIP was considerable, release rates to solution were constrained by slow desorption kinetics (desorption rate constant = 4 × 10-6 s-1) and diffusion rate (effective diffusion coefficient = 6 × 10-9 cm2 s-1. Studies are needed to investigate how changes in temperature, water content, pH and other physical and chemical characteristics can influence antibiotic release kinetics and availability and mobility in biosolid-amended soils.

The costs of registry-based immunization interventions.

BACKGROUND: Part of the payoff of immunization registries may be to lower costs of immunization intervention. However, registry-based intervention costs have not been evaluated in a community setting. METHODS: The purpose of this study was to prospectively measure the cost of three equally effective registry-based interventions, evaluate how the size of the targeted population affects cost estimates, and compare these results with previously reported studies. A total of 3050 children aged <12 months were randomized to one of four study arms: (1) computer-generated telephone messages (autodialer), (2) outreach worker, (3) autodialer with outreach worker backup, or (4) usual care. The cost data collected included capital equipment, supplies, travel, and personnel. RESULTS: Monthly costs of the three registry-based intervention types were (1) autodialer, $1.34 per child; (2) outreach worker, $1.87 per child, and (3) combination, $2.76 per child. Personnel costs represented the majority of incremental costs for all three interventions. Increasing the number of children targeted sharply decreased the cost per child for the autodialer but had only a modest effect on outreach costs. The monthly costs for outreach were substantially lower than previously reported for nonregistry-based interventions in part because of differences in the number of children who were followed up. Monthly costs for the autodialer intervention were slightly higher than previously reported, but several published studies excluded important costs. CONCLUSIONS: By facilitating the management of a larger cohort of children, some registry-based immunization interventions appear to be less costly than nonregistry interventions. Further work is needed to establish whether registry maintenance costs may be recouped in part by these savings.

Comparison of pleural fluid pH values obtained using blood gas machine, pH meter, and pH indicator strip.

STUDY PURPOSE: The purpose of this study was to compare the pleural fluid pH values obtained with a blood gas machine (pHbg), with a pH meter (pHmet), and with a pH indicator strip (pHstrip), to determine if the pleural fluid pH measured by a pH meter or a pH indicator strip was sufficiently accurate for clinical decisions. METHODS: The pleural fluid pH was determined, within 20 min after being collected anaerobically, by a blood gas machine (CIBA-Corning model 288), pH meter (Corning pH meter 610A), and pH indicator strip (Baxter Diagnostic) following routine laboratory procedures in 50 pleural fluids. Pleural fluid pH was determined in seven additional samples with the blood gas machine and a pH meter at 25 and 37 degrees C respectively, initially, and after 30 min. RESULTS: The mean pHbg (7.42+/-0.01) was significantly less than the mean pHmet (7.58+/-0.02) or the mean pHstrip (8.23+/-0.06). There were significant differences between the pHbg and the pHmet (p < 0.001), and between the pHbg and the pHstrip (p < 0.001). Analysis of the additional seven samples demonstrated that when the blood gas machine was set at 25 degrees C, the pHbg (pHbg = 7.54+/-0.02) and the pHmet (7.53+/-0.01) were almost identical. CONCLUSION: When the pleural fluid pH is going to be used for decision making, only the pH values provided by the blood gas machine are sufficiently accurate.

Possible existence of quaternary structure in the high-affinity serotonin transport complex.

Deletion-mutants of the cloned mouse serotonin transporter (SERT) rendered dominant negative-mutant effects upon wild-type transporter activities in heterologous expression studies; such effects were transporter-selective and did not influence the activities of co-expressed neuronal GABA transporter. Heterologous expression of linear concatenates (up to four copies) of SERT further revealed discernable uptake activities for both transporter-dimer and -tetramer, but not for the trimer. Kinetic and pharmacological analyses revealed that the monomer, dimer, and tetramer manifested comparable transport Km and potencies for known serotonin uptake inhibitors; the tetramer was distinct from the others only in manifesting notably reduced transport Vmax. Surprisingly, equivalent cocaine congener-binding activities were observed for all concatenates, including the functionally inactive trimer. These findings collectively support the existence of quaternary structure in the active 5-HT transport complex; such structure is likely to be a critical determinant of ligand transport activities, but apparently not of transporter-inhibitor interactions.

The impact of interventions by a community-based organization on inner-city vaccination coverage: Fulton County, Georgia, 1992-1993.

OBJECTIVE: To evaluate the impact of interventions by a community-based organization on immunization rates. DESIGN: Controlled community intervention trial. SETTING AND PARTICIPANTS: Children aged 3 to 59 months in Fulton County, Georgia, who were patients of 1 of 4 public clinics (clinic based), or residents of 1 of 9 inner-city communities (residence based). INTERVENTIONS: (1) Clinic-based intervention included monthly review of clinic vaccination records to identify undervaccinated children followed by contact with family (reminder-recall strategy); (2) residence-based intervention included door-to-door assessment and education campaigns followed by mobile van vaccinations, temporary on-site vaccination stations, free child care and transportation to providers, incentives of food and baby products, focus groups, and coalitions with local organizations (community saturation with vaccination messages and opportunities). OUTCOME MEASURES: Change in vaccination rates after 1 year based on clinic record reviews and population surveys. RESULTS: For clinic-based intervention, series completion rates improved from 43% (87/204) to 58% (99/170) in intervention clinics (P=.003), while rates in control clinics did not change from the baseline of 52% (81/157 to 78/150), for a net difference between intervention and control arms of +15 percentage points (P=.046). For residence-based intervention, age-appropriate vaccination rates improved from 44% (154/347) to 61% (260/429) in intervention communities (+17 percentage points; P<.001) compared with improvement of 44% (78/178) to 58% (129/221) for control communities (+14 percentage points; P=.004), but the difference between arms was not significant (+3 percentage points, P=.78). CONCLUSIONS: Reminder-recall activities by the community-based organization improved vaccination rates in intervention clinics compared with control clinics. A statistically significant impact on vaccination rates could not be detected for residence-based interventions by the community-based organization.

Cloning and expression of the mouse serotonin transporter.

A mouse brain cDNA encoding the high-affinity serotonin transporter (SERT) has been identified and characterized. The mouse transporter sequence (mSERT) encodes a protein of 630 amino acids which contains twelve potential transmembrane domains (TMDs), N-linked glycosylation and kinase-mediated phosphorylation sites, and high levels of homology with rat and human SERTs. Heterologous expression of mSERT in COS-I cells resulted in a [3H]serotonin transport activity characterized by kinetic saturability (Km = 403 +/- 42 nM. Vmax = 1.02 +/- 0.10 pmol/mg/min), Na1 and Cl- dependences (5HT:Na+:Cl- coupling ratio of 1:1:1), and sensitivity to known inhibitors of serotonin transport (including antidepressant and psychostimulant agents). Northern analysis using mSERT cDNA as probe revealed a single 3.4 kb mRNA species expressed in mouse lung, midbrain and brainstem regions, and absent from heart and liver. In situ hybridization studies further established the specific localization of mSERT gene expression to the raphe nuclei of the mouse midbrain. The identified mSERT cDNA sequence provides a new tool for the evaluation of serotonin transport pharmacology in heterologous expression systems and provides an opportunity for the evaluation of mSERT gene expression in a well-characterized model of mammalian development.

Responsiveness of ovaries to exogenous gonadotrophins and laparoscopic artificial insemination with frozen-thawed spermatozoa in ocelots (Felis pardalis).

Adult female ocelots (Felis pardalis) were treated with one of four dosages of equine chorionic gonadotrophin (eCG) and human chorionic gonadotrophin (hCG) (100 iu eCG/75 iu hCG, n = 3; 200 iu eCG/150 iu hCG, n = 4; 400 iu eCG/150 iu hCG, n = 5; 500 iu eCG/225 iu hCG, n = 5); hCG was administered 80 h after eCG. Ovaries of each animal were evaluated by laparoscopy 39-43 h after hCG, and blood was collected for progesterone and oestradiol analysis. With progressive increases in gonadotrophin dosage, female ocelots produced more (P < 0.05) unovulated follicles (> or = 2 mm in diameter), ranging from 1.3 +/- 0.7 (mean +/- SEM) follicles per female at the lowest dosage to 8.8 +/- 2.8 follicles per female at the highest dosage. Similarly, ocelots produced more (P < 0.05) corpora lutea with increasing gonadotrophin dosages, with mean values ranging from 0-5.0 +/- 1.2 corpora lutea. However, across treatment groups, a similar proportion (P > 0.05) of females ovulated in response to each dosage. At laparoscopy, serum concentrations of oestradiol (overall mean, 330.2 +/- 62.2 pg ml-1) and serum concentrations of progesterone (overall mean, 18.5 +/- 6.4 ng ml-1) in ovulating females did not differ (P > 0.05) across treatment groups. Ten ovulating ocelots were laparoscopically inseminated with fresh (4.7 +/- 0.2 x 10(6); n = 2 females) or frozen-thawed (10.7 +/- 1.8 x 10(6); n = 8 females), motile spermatozoa. One female treated with 500 iu eCG/225 iu hCG and inseminated with 7.5 x 10(6) motile, frozen-thawed spermatozoa conceived and gave birth to a healthy male kitten after a gestation of 78 days. We conclude that ocelots are relatively insensitive to exogenous gonadotrophins, requiring much higher dosages (on a per body mass basis) to elicit an appropriate ovarian response than do any other felid species studied to date. Nonetheless, the gonadotrophin-treated female can become pregnant and carry offspring to term after laparoscopic intrauterine insemination with frozen-thawed spermatozoa.

Structure-activity relationships of serotonin transport: relevance to nontricyclic antidepressant interactions.

A transfectant cell model was used to examine the structure-activity relationships of serotonin (5-hydroxytryptamine, 5-HT) transport. The findings suggest that 5-HT interacts largely with nonpolar and sterically-confining environments on the transport system, and that a particular spatial coordination of the amino and phenyl groups (separated by an alkyl backbone) is important for transport interaction. Molecular modelling analyses revealed that this motif is also present in the structures of several nontricyclic antidepressants and specific inhibitors of 5-HT transport, as well as adrenergic agents which also possess 5-HT transport-inhibitory activities. While this amino-phenyl coordination motif seems to be a necessary structural requisite for transport interaction, and therefore likely to be part of the transport pharmacophore, additional phenyl rings present in some of the nontricyclic antidepressants may help to account for their relatively higher affinities in 5-HT transport interaction.

Evaluation of effects of ozone exposure on influenza infection in mice using several indicators of susceptibility.

Mice were exposed to 1 ppm O3, 3 hr/day, for 5 consecutive days. Separate groups of mice were infected with influenza following each of the individual exposures. A twofold increase in the incidence of mortality and a 3-day decrease in mean survival time were observed in mice infected after the second exposure. There were no effects on percentage mortality or mean survival time due to exposure to 1 ppm O3 in mice infected after the first, third, fourth, or fifth exposure. When the exposure concentration was lowered to 0.5 ppm, there were no effects on mortality in mice infected after the second exposure. Five, daily, 3-hr exposures to 1 ppm O3 had no effect on virus titers in the lungs of mice infected after either the second or fifth exposure. In contrast, wet lung weights were significantly enhanced over infected air controls in mice infected after the second O3 exposure at both 1 and 0.5 ppm but not at 0.25 ppm exposure concentrations. This effect on lung wet weight was observed in mice infected with a dose of virus which produced 7-33% mortality in controls as well as in mice infected with a sublethal dose of virus. Histopathologic changes due to sublethal influenza infection, including nonsuppurative pneumonitis and necrosis, squamous metaplasia and hyperplasia of the epithelium lining the bronchi and bronchioles, were more severe in mice infected after the second of five, 1 ppm O3 exposure than in comparable air controls. Sublethal infection caused a loss of lung volume with secondary reduction in diffusing capability and homogenity of ventilation distribution. These latter two effects were also exacerbated in mice infected after the second of five, 1 ppm O3 exposures as compared to air controls. When mice were infected after the fifth, 1 ppm O3 exposure, there was no effect due to ozone on either lung wet weight or histopathology. The data indicate that O3 has little if any effect on antiviral defense mechanisms since virus titers in the lungs were not affected by O3 exposure. However, mortality and morbidity, as indicated by lung wet weights, histopathology, and pulmonary function changes, were enhanced by O3 exposure in mice infected after the second of five exposures suggesting that symptoms due to infection can be enhanced in the absence of enhanced virus replication, possibly due to synergistic effects of O3 and virus in production of lung pathology.(ABSTRACT TRUNCATED AT 400 WORDS)

The source of murine cytomegalovirus in mice receiving kidney allografts.

The sources of cytomegalovirus (CMV) infection in kidney transplant recipients include reactivation of latent endogenous virus in the recipient or reactivation of latent virus in donated blood or kidney. In the present study, kidneys from mice latently infected with one strain of murine CMV were transplanted into either uninfected recipients or recipients latently infected with a different strain of murine CMV; the recipients were immunosuppressed, subsequently were cultured for murine CMV, and the infecting strain was characterized. The results show that reactivation of latent murine CMV from the donated kidney can be the source of active infection in previously uninfected recipients. When the recipient had been previously infected, however, reactivation of the endogenous recipient strain of murine CMV was the source of active infection in 10 of 12 instances. At no time were both exogenous and endogenous strains of virus reactivated simultaneously. These studies indicate that donor kidney may be the source of latent virus in the uninfected recipient but that endogenous virus predominates in previously infected recipients.

Reactivation of latent murine cytomegalovirus from kidney.

Cytomegalovirus (CMV) is presumed to cause latent infection, but the sites of infection are incompletely known. We propose that latent murine cytomegalovirus is present in kidney and may be reactivated by explanation. Immunosuppressive agents and allogeneic stimuli may enhance this process. Balb/c mice were infected 11 to 14 months previously with 10(5) pfu of Smith strain murine cytomegalovirus intraperitoneally. Kidneys from 15 infected and nine uninfected mice were washed, minced into 1 to 2 mm2 explants and placed into separate tissue culture wells containing a mouse embryo fibroblast monolayer. Explants were untreated or treated with azathioprine, cyclophosphamide, anti-thymocyte serum, or allogeneic lymphocytes. Daily observations for CPE and passage of supernatant to fresh mouse embryo fibroblast were done. Standard cultures of blood, kidney, and salivary gland were negative. However, virus was isolated from the explants of 8/15 animals, with a reactivation time of 30 to 70 days. No significant difference in reactivation time was noted between treated or untreated explants. Restriction enzyme analysis of viral DNA confirmed identity with the original strain. These data show that latent murine cytomegalovirus is present in murine kidney tissue and may be reactivated by explantation.

Magnetic resonance imaging of the cervical spine: technical and clinical observations.

Seventy-two patients were examined to determine the clinical potential for magnetic resonance imaging (MRI) of the spine. MRI using different pulse sequences was compared with plain radiography, high-resolution computed tomography, and myelography. There were 35 normal patients; pathologic conditions studied included canal stenosis, herniated disk, metastatic tumor, neurofibroma, trauma, Chiari malformation, syringomyelia, arteriovenous malformation, and rheumatoid arthritis. MRI provided sharply defined anatomic delineation and tissue characterization. It was diagnostic in syringomyelia and Chiari malformation and was useful in the evaluation of trauma and spinal canal block from any cause. MRI was sensitive to degenerative disk disease and infection. The spin-echo technique, with three pulse sequence variations, seems very promising. A short echo time (TE) produces the best signal-to-noise ratio and spatial resolution. Lengthening the TE enhances differentiation of various tissues by their signal intensity, while the combined increase of TE and recovery time (TR) produces selective enhancement of the cerebrospinal fluid signal intensity.

Nuclear magnetic resonance imaging of the spine.

Forty subjects were examined to determine the accuracy and clinical usefulness of nuclear magnetic resonance (NMR) examination of the spine. The NMR images were compared with plain radiographs, high-resolution computed tomograms, and myelograms. The study included 15 patients with normal spinal cord anatomy and 25 patients whose pathological conditions included canal stenosis, herniated discs, metastatic tumors, primary cord tumor, trauma, Chiari malformations, syringomyelia, and developmental disorders. Saturation recovery images were best in differentiating between soft tissue and cerebrospinal fluid. NMR was excellent for the evaluation of the foramen magnum region and is presently the modality of choice for the diagnosis of syringomyelia and Chiari malformation. NMR was accurate in diagnosing spinal cord trauma and spinal canal block. The normal disc was seen, but with rare exceptions bulging of the annulus and herniation of the nucleus pulposus were not visualized.

The effect of problem difficulty, locus of control, and sex on task persistence.

The purpose of this study was to investigate the influence of problem difficulty, instructional set, locus of control, and sex of S on time expended by college students to solve a puzzle. Three groups of college students (N = 120), each equated for test scores on internal and external locus of control and for sex, were divided as follows: the members of one (n = 40) were told that the problem they were being asked to solve would be difficult; the members of a second were told the problem would be easy; and the members of a third were given no instructions on the difficulty of the problem. The task of the Ss was to form a pattern from a set of small plastic shapes; however, the problem was actually unsolvable. The response measure was the length of time the Ss chose to devote to solving the problem. The results revealed that the Ss in the high difficulty group devoted more time to the task than the Ss in the low difficulty (p less than .06) and control conditions (p less than .05). All other effects were nonsignificant. The results suggested that the Ss in the high-difficulty group perceived their failure to solve the problem to be less of a threat to their self-esteem than did the Ss in the other groups, and as a result devoted more time to the task.

Intravenous digital subtraction angiography of the intracranial veins and dural sinuses.

When combined with computed tomography, IV DSA is usually of sufficient quality to replace conventional angiography in most patients with abnormalities of the larger intracranial veins and sinuses. Preoperatively, IV DSA can be used to evaluate normal anatomic variations of venous outflow to determine what sinuses can be safely occluded if necessary in the region of the temporal bone, jugular fossa, and base of the skull. Patients with glomus jugular tumors and carotid-cavernous fistulas also need conventional angiograms to define the feeding vessels of these lesions for obliteration by embolization or surgery.

Effectiveness of breast self-examination teaching to women of low socioeconomic class.

To assess the effect of a breast self-examination (BSE) teaching program on retention of BSE knowledge and accuracy of BSE performance among women of low socioeconomic class, a pretest-posttest control group design with random assignment to groups was given to women at a Southeastern urban clinic. One hundred eighty women were pretested, after which the experimental group (N = 89) received one-to-one BSE instruction. Seventy of the subjects were given a posttest approximately two months later. All subjects were then asked to demonstrate BSE on themselves. The experimental group subjects showed a significantly greater increase in BSE knowledge from pretest to posttest and performed BSE with greater accuracy than the control group.