Bi-Arrhenius Diffusion and Surface Trapping of

We report measurements of the diffusion rate of isolated ion-implanted ^{8}Li^{+} within ∼120 nm of the surface of oriented single-crystal rutile TiO_{2} using a radiotracer technique. The α particles from the ^{8}Li decay provide a sensitive monitor of the distance from the surface and how the depth profile of ^{8}Li evolves with time. The main findings are that the implanted Li^{+} diffuses and traps at the (001) surface. The T dependence of the diffusivity is described by a bi-Arrhenius expression with activation energies of 0.3341(21) eV above 200 K, whereas at lower temperatures it has a much smaller barrier of 0.0313(15) eV. We consider possible origins for the surface trapping, as well the nature of the low-T barrier.

Sleep and activity monitoring for Returning Soldier Adjustment Assessment.

This paper describes the development of unobtrusive room sensors to discover relationships between sleep quality and the clinical assessments of combat soldiers suffering from post-traumatic stress disorder (PTSD) and mild traumatic brain injury (TBI). We consider the use of a remote room sensor unit composed of a Doppler radar, light, sound and other room environment sensors. We also employ an actigraphy watch. We discuss sensor implementation, radar data analytics and preliminary results using real data from a Warrior Transition Battalion located in Fort Gordon, GA. Two radar analytical approaches are developed and compared against the actigraphy watch estimates--one, emphasizing system knowledge; and the other, clustering on several radar signal features. The radar analytic algorithms are able to estimate sleep periods, signal absence and restlessness in the bed. In our test cases, the radar estimates are shown to agree with the actigraphy watch. PTSD and mild-TBI soldiers do often show signs of sporadic and restless sleep. Ongoing research results are expected to provide further insight.

Continuous remote vital sign/environment monitoring for returning soldier adjustment assessment.

A three-stage study to develop and test an unobtrusive room sensor unit and subject data management system to discover correlation between sensor-based time-series measurements of sleep quality and clinical assessments of combat veterans suffering from Post-traumatic Stress Disorder (PTSD) and mild Traumatic Brain Injury (TBI), is described. Experiments and results for testing sensitivity and robustness of the sensor unit and data management protocol are provided. The current sensitivity of remote vital sign monitoring system is below 20% and 10% for respiration and heart rates, respectively.

Sickle cell disease telemedicine network for rural outreach.

The Medical College of Georgia (MCG) Sickle Cell Center in Augusta, Georgia, USA, provides consultation and (in some cases) primary-care services to more than 1000 patients with sickle cell disease (SCD). Three SCD telemedicine clinic sites were established in rural areas of middle and southern Georgia, based on clinical need; a fourth site had been proposed. Over a 36-month study period, 77 telemedicine SCD clinics were held. There was a mean of 6.1 (SD 2.5) encounters per clinic and 466 total encounters among 128 SCD patients. By using telemedicine, the productivity of the MCG adult sickle cell clinic increased from 1413 to 1889 encounters a year, with an increase in rural outreach activity from 271 to 745 encounters a year. This was accomplished with the addition of a single physician assistant during the last 12 months of the study period; otherwise provider staffing was unchanged. A formal cost-benefit analysis now needs to be carried out.

Use of telemedicine for children with special health care needs.

OBJECTIVE: In 1995, the Children's Medical Services (CMS) of the State of Georgia contracted with the Department of Pediatrics of the Medical College of Georgia (MCG) and the MCG Telemedicine Center to develop telemedicine programs to provide subspecialty care for children with special health care needs. This article presents project statistics and results of client evaluation of services, as well as physician faculty attitudes toward telemedicine. DESIGN: A demonstration project using telemedicine between a tertiary center and a rural clinic serving children with special health care needs was established. Data were collected and analyzed for December 12, 1995 to May 31, 1997, during which 333 CMS telemedicine consultations were performed. RESULTS: Most CMS telemedicine consultations (35%) involved pediatric allergy/immunology. Other subspecialties included pulmonology (29%), neurology (19%), and genetics (16%). Overall, patients were satisfied with the services received. Initially, physician faculty members were generally positive but conservative in their attitudes toward using telemedicine for delivering clinical consultation. After a year's exposure and/or experience with telemedicine, 28% were more positive, 66% were the same, and only 4% were more negative about telemedicine. The more physicians used telemedicine, the more positive they were about it (r =.30). CONCLUSIONS: In terms of family attitudes and individual care, telemedicine is an acceptable means of delivering specific pediatric subspecialty consultation services to children with special health care needs, living in rural areas distant to tertiary centers. Telemedicine is more likely to be successful as part of an integrated health services delivery than when it is the sole mode used for delivery of care.

Sickle cell telemedicine and standard clinical encounters: a comparison of patient satisfaction.

OBJECTIVES: To determine patient satisfaction with telemedicine encounters among adults with sickle cell disease and compare their scores with SCD patients who have standard medical encounters (as controls). METHODS: Adults patients were recruited from a list of participants in sickle cell telemedicine clinics and prospectively at the time of clinic encounter. Patients were assigned to telemedicine or standard encounter groups. Demographic and pertinent clinical data were obtained for all subjects, and the Client Satisfaction Questionnaire (CSQ-8) was administered. Patients were also asked for open-ended comments regarding their satisfaction with the service. Their responses were recorded verbatim. RESULTS: Patients with telemedicine (n = 60) and standard encounters (n = 60) were comparable in gender, genotype, education, employment, and mean number of sickle cell disease-related complications. Patients in the telemedicine group were younger (p< 0.005), more likely to have Medicaid insurance (p = 0.009), and more likely be taking hydroxyurea (p = 0.003) than patients in the control encounter group. Mean CSQ scores for the telemedicine group were high (total: 28.82+/-3.06), and there was no difference for any item between encounter groups (p = 0.389). Patients in the standard encounter group were more likely to provide positive open-ended comments regarding the encounter (95% vs. 70%; p = 0.001). Negative comments were generally in the area of confidentiality. CONCLUSIONS: While some patients expressed concern about confidentiality with telemedicine, the benefits of improved access and continuity of care were recognized, and overall satisfaction with telemedicine was high. These findings support the use of telemedicine as an acceptable health care delivery option for rural, underserved populations with sickle cell disease.

Practice of otolaryngology via telemedicine.

Teleotolaryngology is becoming a reality as a result of improvements in technology and telecommunications. This prospective, clinical trial was designed to demonstrate the utility of three telemedicine systems in an otolaryngology practice. Optel is a desktop system used in the office. Picasso is a mobile system used from various locations throughout the hospital. The Georgia Statewide Telemedicine Program (GSTP) is a large, sophisticated system used from a fixed site within a rural hospital. Patients with a wide variety of ear, nose, and throat problems were presented to consultants at two medical teaching centers in Georgia. Fifty-four consults were completed over a 24-month period. In addition, three teleconsultations demonstrated enhanced capabilities for continuing medical education (CME) and health care networks. Nine different specialty fields were accessed by the otolaryngologist. Five consults were completed via the Optel system; 13 via the Picasso system; and 36 via GSTP. Overall, teleotolaryngology provided quality audio and visual communication between the physicians that significantly improved diagnostic capabilities and treatment options for the patient.

Primary-care delivery for sickle cell patients in rural Georgia using telemedicine.

BACKGROUND: Advances in newborn screening and pediatric management of sickle cell disease have resulted in patients living well into adulthood. For adults, preventive care and medication monitoring are crucial for optimal health maintenance. The Medical College of Georgia (MCG) in Augusta provides consultative services and comprehensive medical care to about 1200 sickle cell patients residing in middle and southern Georgia. An increase in the demand for clinical services in this patient population has resulted in expansion of sickle cell outreach efforts throughout the state. OBJECTIVE: A telemedicine clinic for adult sickle cell patients was established in order to meet the growing clinical demands. METHODS: An on-site outreach clinic was introduced in the target area. After 10 months of operation, a monthly telemedicine clinic was offered to patients as an option for routine medical follow-up. A clinic model was used, with scheduled appointments and a public health nurse assisting at the remote site. Phlebotomy and laboratory services enhanced the telemedicine encounter. RESULTS: Over a 12-month period, 52 encounters for 28 patients from 17 medically underserved counties were completed. All patients were African-American, and 89. 3% had Medicaid or Medicare insurance coverage or both. The clinic encounter time was 24 +/- 7.9 minutes (mean +/- SD), comparable to that for all telemedicine clinic encounters during the same period. CONCLUSIONS: The adult sickle cell population in rural Georgia accepts innovative health care delivery using telemedicine. Thus, the telemedicine sickle cell clinic has increased access to care for rural patients in underserved areas. For providers, it has allowed greater clinical productivity and diminished travel time to outreach clinics.

[Specificity of alcoholism and resulting methods of therapeutic practice]. / Specyfika choroby alkoholowej i wynikajacy z niej sposób pracy terapeutycznej.

Addiction to alcohol is a bodily disease (DSM IV) kept up by certain psychological mechanisms, which are created in order to preserve and justify the need to drink. In the course of alcoholism those mechanisms are modified to form psychological addiction, thus creating, alongside with physical addiction, twofold psychopshysiological addiction. The specific character of the disease requires both medical treatment and psychotherapeutic actions carried out according to certain definite principles aimed at disarming the defence mechanisms which justify a persons right to drink. The actions of therapists working in order to break off a persons addiction should be of approving and instructive character, and at the same time manifest the therapists awareness of the interdependence of physical as well as psychological aspects of the disease. Due to the chronic character of alcoholism and the resulting threat of relapse, what is of particular importance in maintaining ones sobriety are AA support groups.

Physical training, lifestyle education, and coronary risk factors in obese girls.

The effects of supervised physical training (PT) and lifestyle education (LSE) on risk factors for coronary artery disease and non-insulin-dependent diabetes mellitus were compared in obese 7- to 11-yr-old black girls. The subjects were divided into two groups. The PT group (N = 12) completed a 5-d.wk-1, 10-wk, aerobic training program; and the LSE group participated in weekly lifestyle discussions to improve exercise and eating habits. The PT group showed a significant increase in aerobic fitness (P < 0.05) and decrease in percent body fat (P < 0.05), while the LSE group declined significantly more in dietary energy and percent of energy from fat (P < 0.05). Fasting insulin did not change significantly. The LSE group declined significantly more than the PT group in glucose (P < 0.05), and glycohemoglobin declined from baseline in both groups (P < 0.05). Lipid changes were similar in the two groups: total cholesterol/high density lipoprotein cholesterol (P < 0.01) and triglycerides (P < 0.05) declined, the low density lipoprotein (LDL)/apoproteinB ratio increased (which indicates a decrease in small dense LDL) (P < 0.05) and lipoprotein(a) increased (P < 0.05). Thus, the interventions were similarly effective in improving some diabetogenic and atherogenic factors, perhaps through different pathways; i.e., the PT improved fitness and fatness, while the LSE improved diet. Exercise and diet-induced changes in lipoprotein(a) require further investigation.

Relation of percentage of body fat and maximal aerobic capacity to risk factors for atherosclerosis and diabetes in black and white seven- to eleven-year-old children.

OBJECTIVE: To determine whether body fatness, aerobic capacity, and fat distribution are associated with levels of cardiovascular risk factors in children. METHODS: Subjects (N = 57) were 7 to 11 years of age; their percentage of body fat ranged from 10% to 58%. The percentage of fat was measured with dual-energy x-ray absorptiometry, maximal aerobic capacity was measured on a treadmill, fat distribution was expressed as the waist/hip circumference ratio, and blood pressures were measured with an automated monitor. Measurements of several lipoproteins and apoproteins were combined into one atherogenic index. RESULTS: The percentage of fat was related to the atherogenic index (p = 0.38; p > 0.01) and insulin level (p = 0.78; p > 0.001). Aerobic capacity was inversely related to the atherogenic index (p = -0.27; p > 0.05) and insulin level (p = -0.72; p > 0.001). The waist/hip ratio was not related to the risk factors, and blood pressures were not related to fatness or aerobic capacity. In multiple regression analyses, only fatness explained significant independent proportions of the variance in the atherogenic index and insulin level. After control for fatness, the black children had higher insulin levels (p > 0.05). CONCLUSION: At early ages (7- to 11-year-old children), fatness was related to risk factors for cardiovascular disease and diabetes.

Comparative effects of thyroxine and/or retinoic acid treatment in vivo on growth hormone synthesis and release by pituitaries from thyroidectomized rats.

Thyroid hormones and retinoic acid (RA) coregulate growth hormone (GH) synthesis and release from cultured pituitary tumor cells by interacting with nuclear receptors that activate GH gene transcription. Whether these two compounds share overlapping GH regulatory activities in vivo is unclear. Therefore we compared the effects of in vivo replacement therapy with thyroxine (T4) and/or retinoic acid (RA) on GH synthesis and release in pituitaries from hypothyroid rats. Three weeks after thyroidectomy, male rats (100-150 grams, body weight) received 7 days of intraperitoneal T4 (20 ug/kg/day) and/or RA (500 ug/kg/day) or vehicle. Isolated pituitary fragments were incubated for 3 h with [14C]leucine followed by 2 h with [3H]leucine and 3 nM rat growth hormone-releasing hormone (GHRH). Basal synthesis, GHRH-induced release of stored [14C]GH, and GHRH-stimulated release of newly synthesized [3H]GH were assessed by specific immunopercipitation of media and tissue homogenates. T4 increased the synthesis of GH in the absence and presence of GHRH. T4, but not RA, increased the absolute amount of stored and newly synthesized GH released by GHRH. Neither T4 nor RA altered the percent of stored GH released by GHRH, however, both independently or additively decreased the percent of newly synthesized GH released by GHRH. In summary, treatment of hypothyroidism with T4 increased GH synthesis and absolute release. Interestingly the fractional release of GH was unchanged or decreased by T4 treatment. RA treatment had no effect on GH synthesis or absolute release, but like T4 it decreased the fractional release of newly synthesized GH. Thus T4 and RA did not share similar regulatory effects on GH synthesis and stored GH release but did have similar effects on the fractional release of newly synthesized GH in pituitaries from thyroidectomized male rats.

Medium flow rate modulates autocrine-paracrine feedback of GH and PRL release by perifused GH3 cells.

We previously documented both the spontaneous acceleration of growth hormone (GH) and prolactin (PRL) production by GH3 cells during perifusion and the suppression of their production during plate culture. We here present the role played by medium flow itself in this differential behavior. Increasing rates of perifusion flow (pump rates of 1 to 5 ml/h, equivalent to chamber flow rates of 0.19 to 1.3 microliters.min-1.mm-2 of cross-sectional area) were associated with enhanced GH and PRL secretion. Flow rate-dependent basal hormone secretion rates were established quickly and were stable for the first 10 to 14 h of perifusion. The previously documented independent, spontaneous, and continuously accelerating production of both hormones that followed during the subsequent 40 (PRL) to 60 (GH) h of perifusion was also shown to be flow-rate related. Any time the rate of medium flow was changed within an experiment, the rate of hormone secretion was modulated. However, that modulation did not interrupt ongoing flow-associated acceleration of hormone production once the latter had begun. In addition, GH3 cell product(s) from one cell column reversibly inhibited secretion from cells in a downstream column. The inhibition did not occur when cells in the downstream column had been exposed to trypsin. Other work had suggested that neither GH, PRL, insulinlike growth factor-I, leucine, nor nutrient exhaustion were responsible for the effect. These data are consistent with autocrine-paracrine feedback regulation of GH3 cells by a secretory product(s). Feedback would thus provide a mechanism to effect flow-rate-dependent modulation of GH and PRL release, and to explain accelerating hormone production during perifusion.

Contribution of stored rat growth hormone to restoration of depleted rat pituitary immediate release pools.

UNLABELLED: Stored rat pituitary growth hormone (GH) is functionally divided into immediately releasable and more stable compartments. These observations are consistent with either intracellular hormone compartmentalization within cells of a functionally homogeneous somatotroph population or summed responses from a heterogeneous population of functionally specialized cell subgroups. We investigated the pituitary's ability to recruit stored rGH to replenish depleted immediate release pools. We used perifused pituitary fragments whose stored rGH was labeled during pre-incubation in the presence of [3H]leucine. Initial immediate release pool depletion was accomplished by continuous exposure to combined 21 mM potassium ion (K+) and 1 mM dibutyryl cyclic AMP (dbcAMP). During a subsequent perifusion period in the presence of either no secretagogue, continuing 21 mM K+, or continuing 1 mM dbcAMP, we examined release of stored [3H]rGH in response to repetitive 15 min pulses of 21 mM K+ or 1 mM dbcAMP. Analysis was by specific immunoprecipitation. We had demonstrated that K+ and dbcAMP pulses can stimulate repetitive, albeit diminishing, stored [3H]rGH release responses. However, following pre-treatment with combined 21 mM K+ and 1 mM dbcAMP: (i) pulses of dbcAMP stimulated almost no stored [3H]rGH release in the presence of 21 mM K+ or in the absence of a background secretagogue; and (ii) stored [3H]rGH release in response to pulses of K+ was attenuated in the absence of background secretagogue but fully restored in the presence of dbcAMP. CONCLUSIONS: (i) at least some individual somatotrophs can compartmentalize stored hormone; and (ii) an active transport system facilitates restoration of somatotroph immediate release pools using stored rGH.

Ventricular arrhythmias and echocardiographic parameters of the left ventricular morphology in elderly patients with arterial hypertension.

An analysis of cardiac arrhythmias in relation to left ventricular morphology and function was performed in 68 hypertensive patients 60 to 83 years of age. The study comprised Holter monitoring and echocardiography. Our results suggest that in elderly patients with primary arterial hypertension a correlation exists between left ventricular mass and the incidence of ventricular arrhythmias but not between left ventricular mass and supraventricular arrhythmias.

Sleep apnea, sleep disorders, and hypothyroidism.

The symptoms of hypothyroidism are protean and include apathy, somnolence, lethargy, personality change, and intellectual deterioration. Many of these symptoms may be related to hypothyroid-induced sleep disorders. Hypothyroidism is associated with abnormal ventilatory drive, abnormal sleep architecture, and sleep apnea. Central, obstructive, and mixed patterns of sleep apnea are commonly observed in hypothyroidism. A case of severe sleep apnea in a grossly myxedematous patient who improved dramatically following thyroid replacement alone is presented. Myxedema is a reversible cause of sleep apnea, and thyroid function testing should be considered in its diagnostic work-up.

Pituitary immediate release pools of growth hormone and prolactin are preferentially refilled by new rather than stored hormone.

Pituitary stores of rat GH (rGH) and PRL (rPRL) are divisible into immediately releasable and more stable compartments representing either compartmentalized hormone within individual cells of a homogeneous population or responses of specialized cell subsets in a functionally heterogeneous population. In addition, newly synthesized rGH and rPRL can be processed either into intracellular storage or toward direct release. Fractional assignment of new hormone to these two paths can be influenced in the somatotroph by GHRH and may also represent either intracellular processes or functional heterogeneity of cells. We investigated the source, newly synthesized or stored, of hormone refilling the somatotroph and lactotroph immediately releasable pools (IRP) after their discharge by 21 mM potassium ion, 1 mM (Bu)2cAMP, 3 nM human GHRH-44, or 3 microM prostaglandin E1. Experiments were performed using perifused pituitary fragments exposed sequentially to [14C]- and [3H]leucine in association with stimulation by two 30-min pulses of the same secretagogue. Therefore, only [14C]hormone was available for release by the first stimulus, whereas both [14C]- and [3H]hormone were available for release by the second stimulus. Analysis was by specific immunoprecipitation. The first episode of stored [14C]rGH release exceeded the second episode of stored [14C]rGH release in response to each secretagogue. However, release of newly synthesized [3H]rGH in response to the second episode of stimulation exceeded the simultaneous release of stored [14C]rGH while matching or exceeding the [14C]rGH release that had occurred in the same experiment in response to the first episode of stimulation. Refilling both GH and PRL IRP stores drew primarily upon newly synthesized hormone, but with different secretagogue-specific patterns. These data confirm differential handling of new and stored rGH and rPRL within the pituitary. They are consistent with either (1) the enhanced shunting of newly synthesized hormone to IRPs within cells that are capable of compartmentalized intracellular hormone storage, or (2) the relatively complete discharge of a subset of somatotrophs and lactotrophs that are specialized to deliver pulsed hormone release, after which they are refilled by newly synthesized hormone.

Autocrine-paracrine inhibition of growth hormone and prolactin production by GH3 cell-conditioned medium.

In previous work we have shown that perifused GH3 cells exhibit spontaneously accelerating growth hormone (GH) and prolactin (PRL) secretory rates. This behavior contrasts with GH and PRL secretion rates that are decreasing or stable over the same 3-d period in static cell culture. We now report that GH3 cells maintained in serum-supplemented medium produce an autocrine-paracrine factor(s) which inhibits GH secretion in plate culture; PRL release is frequently reduced as well. The inhibitory effect of conditioned medium on GH secretion was concentration dependent, whereas PRL release was stimulated at low and inhibited at high concentrations over the same range. Extensive dialysis of conditioned medium using membranes with a molecular weight cut-off of 12,000-14,000 did not remove GH inhibition but produced a retentate that stimulated PRL secretion. Heat-inactivation of conditioned medium did not abolish inhibition of GH release but did remove the PRL-stimulatory effect. IGF-I added to fresh culture medium did not reproduce the GH-inhibitory effects of conditioned medium. We conclude that GH3 cell secretory behavior in perifusion and plate culture systems may be partially explained by the production of an autocrine-paracrine factor: its accumulation in plate culture inhibits GH and PRL secretion whereas its removal, by perifusing medium, allows GH and PRL secretion to accelerate.