The Assessment of Post-COVID Fatigue and Its Relationship to the Severity and Duration of Acute COVID Illness

Emerging data suggests that COVID-19 is associated with fatigue well beyond the acute illness period. The present analysis aimed to: (1) characterize the prevalence and incidence of high fatigue at baseline and follow-up; (2) examine the impact of COVID-19 diagnosis on fatigue level following acute illness; and (3) examine the impact of acute COVID-19 symptom severity and duration on fatigue at follow-up. Subjects (n = 1417; 81.0% female; 83.3% White; X¯age = 43.6 years) completed the PROMIS-Fatigue during the initial wave of the pandemic at baseline (April-June 2020) and 9-month follow-up (January-March 2021). A generalized linear model (binomial distribution) was used to examine whether COVID-19 positivity, severity, and duration were associated with higher fatigue level at follow-up. Prevalence of high fatigue at baseline was 21.88% and 22.16% at follow-up, with 8.12% new cases at follow-up. Testing positive for COVID-19 was significantly associated with higher fatigue at follow-up. COVID-19 symptom duration and severity were significantly associated with increased fatigue at follow-up. COVID-19 symptom duration and severity during acute illness may precipitate longer-term fatigue, which could have implications for treatment planning and future research. Future studies should further evaluate the relationship between symptom severity, duration, and fatigue.

0570 Does CBT-I Dose effect Sleep Duration and Fatigue in Breast and Prostate Cancer Patients?

Introduction

Cancer-related fatigue (CRF) is highly prevalent during acute illness and survivorship, with almost 100% of cancer patients experiencing some level of CRF. While CRF commonly co-occurs with sleep disturbance during and/or after cancer treatment, CRF is defined as occurring independent of sleep considerations. The present analysis is based on an ongoing pilot study where CBT-I dose (4 & 8 [Low] vs 10 & 12 [High] sessions) is being assessed for whether improved sleep continuity and/or increased TST can improve CRF in subjects diagnosed with breast and prostate cancer.

Methods

This interim analyses includes seven adult subjects (6 females, mean age=57.1 yrs.; n=3 [Low dose], n=4 [High dose]). CBT-I was provided by a master CBT-I therapist via video conferencing (telehealth CBT-I). Subjects were asked to complete sleep diaries, and weekly measures of fatigue (FACIT) and insomnia severity (ISI) questionnaires.

Results

Subjects in the low dose group exhibited a 9% improvement and subjects in the high dose group had a 21% improvement on the FACIT. This corresponded to a 28% improvement on the ISI (low group) and a 68% improvement on the ISI (high group). With respect to TWT, subjects in the low dose group decreased their wake time by 36% and those in the high dose group decreased their wake time by 43%. Finally, TST decreased by 7% in the low dose group but increased by 12% in the high dose group.

Conclusion

Preliminary results indicate that a higher CBT-I dose may significantly decrease fatigue, stabilize sleep schedules, and improve sleep continuity in patients with CRF, where the high dose group showed more than double the improvement on the FACIT and ISI (as compared to the low dose group). Not surprisingly, TWT was roughly comparable between the groups while TST was more substantially impacted by high dose CBT-I. This study is ongoing.

Support (If Any)

Support: 5T32HL00795320;K24AG055602

0427 Having Insomnia vs. Identifying as an “Insomniac”: What is the role of insomnia severity?

Introduction

The present study sought to evaluate whether insomnia severity (i.e., sleep continuity disturbance) is worse in those who endorse insomnia identity (i.e., identify as an “insomniac”) vs. those who endorse “having insomnia.”

Methods

This study utilized a cross-sectional group design in an archival/community dataset that was collected in the Philadelphia area. This dataset (n=3,483) was comprised of adults between 18 and 90 years of age (X̅age=53.6±11.0; female [76.4%]; White [91.4%]). All subjects in this analysis endorsed sleep problems. Subjects answered questions regarding demographics, sleep continuity (in minutes), and insomnia identity (“Do you think of yourself as someone that has insomnia” and “do you think of yourself as an ‘insomniac’"?). For both questions, individuals were categorized by their answers: strongly agree, agree, undecided, disagree, strongly disagree. MANOVAs and two-way ANOVAs were conducted to assess group differences (α=.01).

Results

Most individuals endorsed “having insomnia” (n=2,301 [66.1%; strongly agree and agree]) but did NOT endorse being an ‘insomniac’ (n=1,981 [56.9%; undecided, disagree, and strongly disagree]). For all measures, except TST, the two groups did not differ with respect to insomnia severity (i.e., SL[55.4±48.5;60.5±52.1], WASO[45.1±51.7;47.6±55.3], EMA[71.8±51.6;72.9±52.4], and TST [328±75.5;319.6±76.4, p=.009]). The magnitude of the differences between these groups ranged from 1-10 minutes.

Conclusion

It was found that individuals are more likely to endorse ‘having insomnia’ than they are to endorse being an ‘insomniac.’ Despite the implicit differences in “having” something vs. “being” something, the groups did not differ appreciably with respect to sleep continuity. Thus, the tendency to have insomnia identity may not be related to insomnia severity considerations. It is possible, if not likely, that such differences may be related to frequency or chronicity of insomnia. Barring, or in addition to these things, insomnia identity may be related to the mismatch between sleep ability and need and/or related to other non-specific factors. Future directions include refining the group definitions to include forms of insomnia identity that occur with relatively normal sleep continuity (i.e., normal severity and/or frequency and/or chronicity). It will also be important to evaluate whether the various forms of insomnia identity vary with age, sex, or disease comorbidity.

Support (If Any)

K24AG055602

0461 Does “TIB” Differentiate Between Good Sleepers and Subjects That Develop Acute or Chronic Insomnia? A 2nd Analyses

Introduction

According to the 3P model of insomnia, the variable that mediates the transition from acute to chronic insomnia is “sleep extension” (the behavioral tendency to expand sleep opportunity to compensate for sleep loss). Recently, this proposition was prospectively evaluated by assessing how Time-in-Bed (TIB) varied, week-by-week, relative to the incidence of acute insomnia in four groups, those that: maintained good sleep (GS,n=911), recovered good sleep (AI-REC,n=244); had persistent poor sleep (AI-PPS,n=65); and developed chronic insomnia (AI-CI,n=23)). Significant differences for pre-to-post acute insomnia TIB were not detected for the insomnia groups (as compared to one another or as compared to GSs). The observed trends suggested that the increases in TIB observed were minor (< 15 min overall, at 2 weeks, and at 12 weeks post AI). In the present analysis, a more granular evaluation was undertaken to assess whether sleep extension occurs on the nights following poor sleep bouts.

Methods

The same data set and subject groups were modeled for TIB occurring on the night following a poor night’s sleep (≥ 30 min for SL or WASO or EMA) for the post-acute insomnia interval (by weekday and weekend). Linear mixed effects model was used to account for up to 1 year of repeated nights per subject.

Results

During the weekdays, the groups did not differ with respect to TIB following a poor nights’ sleep. On average, the four groups (including good sleepers) did not vary TIB by more than 5 minutes. During the weekends, all four groups tended to restrict TIB. In this instance, AI-CI subjects restricted TIB the least (AI-CI -17.2[5.11]; (GS -25.7[SE 1.58]; AI-PPS -27.6[6.1]; AI-REC -32.3[1.9].

Conclusion

As with the prior analysis, the transition to CI does not appear to be triggered by sleep extension. In the present analysis there is some evidence to support the notion that AI-CI subjects restrict TIB less. This counterintuitive finding needs to be further evaluated taking into account sleep timing. That is, time-to-bed and time-out-of-bed may vary (show the attempt to extend sleep opportunity) while TIB does not change appreciably (owing to limitations in sleep ability [plasticity]).

Support (If Any)

Support: R01AG041783;K24AG055602;R01AT003332

Durability of treatment response to zolpidem using a partial reinforcement regimen: does this strategy require priming?

BACKGROUND

Previous research has shown that after one month of full dose nightly treatment with zolpidem (priming), subjects with chronic insomnia (CI) switched to intermittent dosing with medication and placebos were able to maintain their treatment responses. This approach to maintenance therapy is referred to as partial reinforcement. The present study sought to assess whether priming is required for partial reinforcement or whether intermittent dosing with placebos (50% placebos and 50% active medication) can, by itself, be used for both acute and extended treatment.

METHOD

55 CI subjects underwent a baseline evaluation (Phase-1) and then were randomized to one of two conditions in Phase-2 of the study: one month of (1) nightly medication use with standard-dose zolpidem (QHS [n = 39]) or (2) intermittent dosing with standard-dose zolpidem and placebos (IDwP [n = 16]). In Phase-3 (three months), the QHS group was re-randomized to either continued QHS full dose treatment (FD/FD) or to IDwP dose treatment (FD/VD). Treatment response rates and Total Wake Time (TWT = [SL + WASO + EMA]) were assessed during each phase of the study.

RESULTS

In Phase-2, 77% (QHS) and 50% (IDwP) subjects exhibited treatment responses (p = 0.09) where the average change in TWT was similar. In Phase-3, 73% (FD/FD), 57% (FD/VD), and 88% (VD/VD) of subjects exhibited continued treatment responses (p = 0.22) where the average improvement in TWT continued with FD/FD and remained stable for FD/VD and VD/VD (p < 0.01).

CONCLUSION

These results suggest that intermittent dosing with placebos can maintain effects but do not allow for the additional clinical gains afforded by continuous treatment.

754 Insomnia and Depression Symptoms in Primary Care Patients Referred for Mental Health Care

Introduction

Past epidemiological research indicates that insomnia and depression are both highly prevalent and tend to co-occur in the general population. The present study further assesses this association by estimating: (1) the concurrence rates of insomnia and depression in outpatients referred by their primary care providers for mental health care; and (2) whether the association between depression and insomnia varies by insomnia subtype (initial, middle, and late).

Methods

Data were collected from 3,174 patients (mean age=42.7; 74% women; 50% Black) who were referred to the integrated care program for assessment of mental health symptoms (2018–2020). All patients completed an Insomnia Severity Index (ISI) and a Patient Health Questionnaire (PHQ-9) during their evaluations. Total scores for the ISI and PHQ-9 were computed. These scores were used to categorize patients into diagnostic groups for insomnia (no-insomnia [ISI &lt; 8], subthreshold-insomnia [ISI 8–14], and clinically-significant-insomnia [ISI&gt;14]) and depression (no-depression [PHQ-914]). Items 1–3 of the ISI were also used to assess the association between depression and subtypes of insomnia.

Results

Rates of insomnia were as follows: 34.6% for subthreshold-insomnia, 35.5% for clinically-significant insomnia, and 28.9% for mild-depression and 26.9% for clinically-significant-depression. 92% of patients with clinically significant depression reported at least subthreshold levels of insomnia. While the majority of patients with clinical depression reported having insomnia, the proportion of patients that endorsed these symptoms were comparable across insomnia subtypes (percent by subtype: initial insomnia 63%; middle insomnia 61%; late insomnia 59%).

Conclusion

According to these data, the proportion of outpatients referred for mental health evaluations that endorse treatable levels of insomnia is very high (approximately 70%). This naturally gives rise to at least two questions: how will such symptomatology be addressed (within primary or specialty care) and what affect might targeted treatment for insomnia have on health were it a focus of treatment in general?

Support (if any)

Vargas: K23HL141581; Perlis: K24AG055602

368 Durability of Tx Response to Zolpidem using a Partial Reinforcement Regimen: Does this strategy require contingent reinforcement?

Introduction

In 2015, partial reinforcement (PR) was assessed as an alternative approach to maintenance therapy with zolpidem. The method being: once a treatment response is obtained over the course of 1-month’s Tx with QHS dosing (Phase-1), Tx response can maintained over time with a PR regimen (Phase-2 [nightly pill/capsule use with 50% of capsules having medication and 50% having only inert filler]). In that study, it was assumed that Phase1 QHS dosing was required 1) to maximize treatment responding and 2) for the conditioning of pharmacologic responses to the medication vehicle (capsule). In the present study, these assumptions were tested by including both QHS and PR arms into Phase-1.

Methods

In Phase-1 (1 month), subjects were randomized to the QHS or PRS conditions (2QHS:1PRS). In Phase-2 (3 months), the PRS group continued forward without a change in the treatment regimen (variable dose [VD-VD]) and the QHS group was re-randomized to either continued QHS Tx (full dose [FD-FD]) or to PRS Tx [FD-VD]). Both study phases were evaluated for treatment responses rates and for average change in TWT (SL+WASO+EMA).

Results

55 subjects (age 61.2+/-8.1, 64% female, & 73% white) were enrolled into Phase-1; 39 were randomized to the QHS condition and 16 to the PRS condition. In Phase-1, 77% (QHS) and 50% (PRS) exhibited treatment responses (p=0.09) where the average change in TWT was similar by group (QHS was -43min [CI -76,-9] and PRS was -76min [CI -138,-14];p=0.35). In Phase-2, 73% (FD-FD), 57% (FD-VD), and 88% (VD-VD) exhibited continued treatment responses (p=0.22) where the average improvement of TWT continued with FD-FD and remained stable for FD-VD and VD-VD (p&lt;0.01).

Conclusion

These data, while preliminary, suggest that QHS (vs. PRS) dosing produces more treatment responders and similar initial effects on sleep continuity during Phase-1, comparable maintenance of treatment response over time, and continued improvement on sleep continuity during Phase-2. These results suggest that partial reinforcement can maintain effects but cannot allow for the additional clinical gains afforded by continuous treatment. Given this, it may be the case that the partial reinforcement technique could be improved upon by extending phase from 1 to 2–4 months.

Support (if any):

0152 Insomnia Severity and Daytime Complaints: What is to be Learned When These Domains are Discordant?

Introduction

If illness severity and daytime dysfunction are construed as categorical entities, it is possible to conceptualize the relationship between these variables in terms of a 2x2 matrix where the resultant cells represent a concordant dimension (quadrants 2 & 4 [high-high and low-low]) and a discordant dimension (quadrants 1 & 3 [high-low and low-high]). The question for the present analysis was, what percentage of subjects populate each quadrant and is it the case that the discordant dimension contains only a small percentage of subjects?

Methods

Illness severity and daytime dysfunction data was collected from individuals with sleep continuity complaints in archival/community-based sample (N = 4680; 60% female; Ages 18–89) (www.sleeplessinphilly.com). Illness severity was operationalized as Total Wake Time (TWT; [SL+WASO+EMA=TWT]) and daytime dysfunction was operationalized as the composite score of six daytime symptoms items. Median splits were calculated for each variable and subjects were typed accordingly (HH, LL, HL, & LH).

Results

Surprisingly, the sample was relatively equally distributed into the two dimensions; 38% and 23% for the concordant dimension and 13% and 26% for discordant dimension.

Conclusion

The 39% of subjects in the discordant groups might be thought of as complaining good sleepers (LH) and noncomplaining poor sleepers (HL). Other investigators have identified the LH subjects as individuals with “insomnia identity”. Alternatively, it is possible to characterize the whole dimension as being related to a mismatch between the individual’s sleep need and sleep ability. Those who need a lot, may suffer a lot, in the face of only a little (LH) whereas those who need a little, may suffer only a little, in the face of a lot (HL).

Support

 

1109 Broadly Assessing Sleep Complaints In A Sample Of Patients With ADHD

Introduction

It is commonly observed in clinical settings that patients with ADHD regularly present with comorbid “sleep disturbances”. In the absence of broad based sleep disorders assessments, it is thought that this represents Delayed Sleep Phase Disorder (DSPD). Recently, a surveillance study was undertaken in a university-based, outpatient specialty clinic for adults with ADHD, by adding a comprehensive sleep disorders screener (SDS-CL-25) to the clinical intake procedures. These data were used to ascertain which sleep disorders symptoms are common in this clinical cohort.

Methods

SDS-CL-25 data were collected in 150 subjects (93/57 male/female, mean age 32.8, age range 18-79). The SDS-CL-25 is a 25 item instrument developed to screen for 13 sleep disorders at one time (Sleep Dx symptoms are endorsed on Likert-scales; 0 [never] 4 [&gt;5x/week]). For the purposes of this study, the percentage of subjects endorsing frequent symptomatology (sum of the percent of endorsements for columns 3 & 4)was calculated per symptom. Sums of &gt;20% were considered, a priori, to be of clinical significance.

Results

Patients endorsed: increased fatigue (59%); SL or WASO or EMA’s &gt;30 minutes (40%; 26%; 21%, respectively); late preferred time to bed (31%); work & school limits sleep opportunity (30%); variable time to and out of bed (27%); and snoring (21%). The average percent endorsement was 15% (range 0-59%).

Conclusion

These results suggest that, consistent with clinical observations, adult patients diagnosed with ADHD frequently endorse late preferred time to bed, variable sleep wake schedules, work/school limitations on sleep opportunity, and sleep onset problems that are accompanied by daytime fatigue. This constellation of symptoms is consistent with the notion that patients with ADHD tend to have comorbid DSPD. The high prevalence of middle and late insomnia was unexpected and suggests that Insomnia Disorder (proper) may also be a feature of ADHD.

Support

No support was provided for this abstract.

0153 Patient-Defined Insomnia Severity: How Much Wakefulness is Problematic?

Introduction

While Insomnia Disorder is formally defined in the ICSD-3 and DSM-5, neither diagnostic system adopts quantitative criteria for illness severity. Interestingly, quantitative criteria are provided for frequency and chronicity (i.e., ≥ 3 days / week for ≥ 3 months). For research purposes, illness severity has long been defined using the “30 minute rule” (SL and/or WASO and/or EMA of ≥ 30 minutes is the threshold for clinical relevance). In the present analysis, this threshold was assessed for its significance to patients.

Methods

Sleep continuity disturbance (SCD; SL, WASO, and EMA) and problem endorsement data were collected from an archival/community-based sample (N = 4680; 60% female; Ages 18–89 years; www.sleeplessinphilly.com). Problem endorsement was evaluated through questions that included, “Do you consider this a problem?” after participants reported length of SL, WASO, and EMA. Problem endorsement percentages were calculated for 5 minute bins for between 0 and 65 minutes, with one additional bin for &gt; 65 minutes. The temporal bins were compared for significant deviations using absolute (percent of subjects at 0–5 and 5–10 minutes) and moving references (last significant percent).

Results

The first temporal bin to differ from the absolute reference for SL, WASO, and EMA was the 26–30 minute bin. At this threshold, 87%, 70%, and 94% of the subjects’ identifying SL, WASO and EMA as being problematic (and was deemed statistically different from “normal” [0–10 minute values]).

Conclusion

These data suggest that the “30 minute rule” (which is of unknown provenance) roughly corresponds to the level of illness severity (lowest common threshold) identified by patients as problematic. While the threshold for SL and EMA show a clear majority, the lower percentage of subjects for WASO suggests that people are more tolerant of middle of the night wakefulness.

Support

 

1111 Do Sleep Disorder Symptom Endorsements Differ Between ADHD Subtypes?

Introduction

To date, research on differences in sleep complaints between patients with different subtypes of ADHD has been mixed. On balance, the evidence tends towards ADHD-Combined Presentation (ADHD-C) being associated with more severe sleep and sleep-related daytime complaints than ADHD-Primarily Inattentive (ADHD-I). In order to further assess this issue a surveillance study was undertaken in an active ADHD clinic by adding a comprehensive sleep disorders screener (SDS-CL-25) to the clinical intake procedures. These data were used to ascertain whether the two subtypes differ for any of 13 sleep disorders symptoms.

Methods

Subjects (n = 132; 83 male, 49 female, mean age 32.8, age range 18-79), presenting to the clinic for evaluation for ADHD were given the SDS-CL-25. The SDS-CL-25 is a 25-item instrument developed to screen for multiple sleep disorders at one time (problems are endorsed on a Likert-scale; 0 = never and 4 = more than 5x/week). Endorsements greater than 3x/week were counted as positive for the symptom and less than three days per week was considered negative.

Percent per group was compared using Chi Square Analyses. Cumulative morbidity means were also analyzed using t-tests. The subtype, ADHD-I (n=71) and ADHD-C (N=61), was established using EMR records.

Results

No significant differences between patients with ADHD-I and ADHD-C were detected.

Conclusion

The lack of finding in the present analysis may reflect a lack of difference or a failure to detect differences based on the small sample sizes or lack of statistical control for likely confounders (age, sex, illness severity or chronicity, SES status, etc.). Analyses are ongoing.

Support

No support was provided for this abstract.

P1840Mid-term results of bioprosthetic aortic valve replacement with the Trifecta valve: A word of caution

Background

Structural valve deterioration (SVD) with associated bioprosthetic valve dysfunction remains an unsolved problem, exposing patients to the risk of aortic valve re-intervention after surgical aortic valve replacement (SAVR). Several strategies have been proposed to improve prosthesis design for optimal performance. The leaflets of the Trifecta valve are mounted on the outside of the prosthetic stent to achieve a larger orifice area. Although favourable early clinical outcomes have been reported, long-term durability still needs to be assessed.

Purpose

The aim of the current study was to assess the mid-term overall mortality and re-intervention rate in patients who received a Trifecta valve with a follow-up >5 years.

Methods

Patients who underwent SAVR at our centre between 2011 and 2012 were identified in the internal, prospective database. All patients with implantation of a Trifecta valve in aortic position were included. Primary endpoints were freedom from overall mortality and from re-operation at latest follow-up (FU). Additionally, assessment of echocardiographic parameters at baseline and follow-up was performed.

Results

Seventy-six patients (age 77.3±9.5 years, BMI 28.6±5.8, 68% male) were included in the study. EuroScore II was 7.2% (± 7.7) while mean STS-Mortality score was 2.4±1.1%. Of all procedures, 53% were isolated aortic valve replacements, whereas concomitant procedures were performed in 47% of cases (37% CABG, 12% mitral surgery, 8% tricuspid surgery). Baseline echocardiographic assessment showed a mean pressure gradient (MPG) of 51±21 mmHG, a peak pressure gradient (PPG) of 78±36 mmHG and a peak velocity (Vmax) of 4.2±1.1 m/s.

Thirty-day mortality was 7%. Freedom from overall mortality at 1 year and 5 years was 84% and 73%, respectively. Freedom from death and freedom from re-operation at latest FU (6.7±0.5 years) was 68% and 90%, respectively. In a composite endpoint analysis, freedom from death or re-intervention at latest follow up was 60%. A total of 7 patients underwent aortic valve re-interventions (re-replacements n=5, valve-in-valve n=2). Indications for re-interventions were SVD (n=5), NSVD (n=1, pannus ingrowth) and endocarditis (n=1). One case of re-stenosis occurred in a patient who was deemed not feasible for aortic valve re-intervention and died.

Kaplan Meier analysis

Conclusion(s)

To our knowledge, this patient cohort presents with the lowest rate of freedom from re-operation (90%, 6.7±0.5 years) after SAVR with the Trifecta valve. A relatively high number of SVD and NSVD has been observed, which might be attributable to the specific leaflet mounting or the deformable valve frame of the first generation. Current results call for further investigation with prospective echocardiographic follow-up in this patient group.

Acknowledgement/Funding

None

Antibiotic therapy for diabetic foot infections: comparison of cephalosporines with chinolones

Diabetic foot complications are the most common cause of non-traumatic lower extremity amputations and uncontrolled infections represent a major risk factor. This open prospective, multicenter trial compared the efficacy of two antibiotic regimens for treatment of foot infections Wagner stage II or III in diabetic adults. Three hundred diabetic patients with severe, limb-threatening foot infection were consecutively enrolled in a prospective, observational, matched pairs controlled study to test two different antibiotic regimes (ceftriaxone vs chinolones) in addition to standard treatment of foot infection. After matching, 90 patients--each receiving ceftriaxone or chinolones--were analyzed. Our study demonstrated that treatment with a third generation cephalosporine is as effective as a treatment with chinolones. Response (reaching Wagner I or 0) was achieved in 58.0% in the ceftriaxone group and in 51.1% in the chinolone group (NS.). Fourteen days after initiation of treatment, the number of patients with microbiological isolates decreased in both groups (52 to 5 in the ceftriaxone group and 60 to 12 in the chinolone group). At hospital discharge, 66.0% of ceftriaxone and 64.4 of chinolone-treated diabetic ulcers were cured or improved. In summary, both substances proved to be effective in the primary antibiotic treatment of the diabetic foot; an early broad spectrum antibiotic treatment, that covers both gram-positive and gram negative bacteria as well as anerobes is undisputedly an imperative therapeutic intervention for the treatment of diabetic foot infection.

Effects of alprazolam and bromazepam on visual search and verbal recognition memory in humans: a study with event-related brain potentials

The effects of two benzodiazepines (alprazolam and bromazepam) on performance and event-related brain potentials (ERPs) in visual search and verbal recognition memory paradigms were tested in a placebo-controlled double-blind paradigm employing 12 young healthy subjects. Both drugs exerted similar effects on performance and electrophysiological measures. Reaction times and hit rates were adversely affected in both paradigms. The ERP pattern in the visual search experiment suggested an impairment in selective attention (reduction of N1 component) and of automatic feature registration (posterior N2 reduction). In the world recognition experiment a dramatic reduction of the N400 component was seen under benzodiazepines. This is interpreted as reflecting an impaired ability to perform context integration processes.

Inhibition of growth factor binding and intracellular Ca2+ signalling by dextran sulfates of different sizes and degrees of sulfation

The ability of dextran sulfates of varying molecular sizes (5-500 kDa) and degrees of sulfate substitution (0.3-1.9) to inhibit the binding of platelet-derived growth factor (PDGF) to intact Swiss 3T3 fibroblasts and to inhibit inositol(1,4,5)trisphosphate-dependent release of Ca2+ in permeabilized Swiss 3T3 cells was examined in the present study. Significant correlations were found between increased molecular size of the dextran sulfates and inhibition of both PDGF binding (r = 0.77) and Ca2+ release (r = 0.72). The degree of sulfate substitution did not correlate with inhibition of either activity.

Bacteremia during extracorporeal shock wave lithotripsy of renal calculi

An increasing incidence of bacterial endocarditis has been observed since the beginning of the last decade. An explanation for this fact is the expansion of diagnostic and therapeutic procedures in diverse medical disciplines. In a clinical study performed on 49 consecutive patients undergoing extracorporeal shock wave lithotripsy a 14.3% rate of bacteremia was detected during treatment. The bacterial spectrum consisted of gram-positive cocci, gram-negative cocci, Bacteroides capillosus and Proteus mirabilis. In principle, these results do not call for an antibiotic prophylaxis. Nevertheless, according to the recommendations of the American Heart Association and the Deutsche Gesellschaft für Herz- und Kreislaufforschung, patients with a cardiac risk predisposing to bacterial endocarditis must receive perioperative antibiotic prophylaxis.

[Incidence of bacteremia following extractions--a double blind study on local disinfection using chlorhexidine]

In a randomised double-blind study the incidence of bacteremia after two minutes mouth rinsing with chlorhexidine 0.1% followed by tooth extractions was registered. A significant reduction of bacteremia could not be observed in comparison with mouth rinsing with physiological saline solution. Tooth extractions always require the preventive administration of antibiotics to patients known with high risk of endocarditis.

Contribution of external and internal Ca2+ to changes in intracellular free Ca2+ produced by mitogens in Swiss 3T3 fibroblasts: the role of dihydropyridine sensitive Ca2+ channels

Changes in intracellular free Ca2+ concentration [( Ca2+]i) produced by growth factors and mitogens have been studied using aequorin-loaded Swiss 3T3 cells. Decreasing free Ca2+ in the external medium by using EGTA had no significant effect on the increase in [Ca2+]i produced by vasopressin, bradykinin, bombesin or prostaglandin E2, but reduced the increase in [Ca2+]i produced by platelet derived growth factor (PDGF) by 58%, by prostaglandin E1 44% and by prostaglandin F2 alpha 47%. The dihydropyridine Ca2+-channel antagonist nifedipine at 10 microM inhibited the [Ca2+]i response to PDGF by 41% in both the presence of and in the absence of external Ca2+. Methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl) pyridine-5-carboxylate (BAY K8644), a Ca2+-channel agonist, at 10 microM produced an increase in [Ca2+]i and decreased the [Ca2+]i response to PDGF by 39%. Nifedipine did not block 45Ca2+ uptake or release by inositol 1,4,5-trisphosphate in saponin-permeabilized Swiss 3T3 fibroblasts but BAY K8644 inhibited 45Ca2+ release by inositol 1,4,5-trisphosphate. The results suggest that the increase in [Ca2+]i caused by PDGF in Swiss 3T3 fibroblasts is due to the influx of external Ca2+ through dihydropyridine sensitive Ca2+ channels, as well as release of internal Ca2+.

Separation of major phospholipid classes by high-performance liquid chromatography and subsequent analysis of phospholipid-bound fatty acids using gas chromatography

A sensitive high-performance liquid chromatographic method for the separation of major phospholipid (PL) classes in biological materials is described. Using this method it was easy to separate P-cholin, P-ethanolamine, P-serine, P-inositol, cardiolipin, sphingomyelin, lyso-P-choline and lyso-P-ethanolamine from skeletal and cardiac muscle samples. The method is based on the simultaneous use of a pH gradient and a polarity gradient. This procedure can easily be modified to optimize the separation of PLs from very different tissues. Subsequent analysis of the PL-bound fatty acids (FAs) by gas chromatography resulted in a well separated FA pattern. Following this FA separation it was possible to recalculate the specific PL content in the original sample.

The use of Fura-2 to estimate myoplasmic [Ca2+] in human skeletal muscle

Fura-2 was used to estimate myoplasmic [Ca2+] in intact fibers and fiber segments from normal and diseased human muscles. Small muscle bundles (20-50 fibers) were loaded with the membrane-permeant form of the dye (Fura-2 AM). High-performance liquid chromatography was utilized to study the ability of these cells to hydrolyze Fura-2 AM. Immediately after the 30 min loading period, Fura-2 (the Ca2+ indicator) was the predominant form of the dye in all preparations and the concentration within these fibers remained stable for over 4 1/2 hours. In addition, the resting myoplasmic [Ca2+] in fiber segments from normal subjects and those susceptible to malignant hyperthermia were the same. However, halothane administration (1.5%) induced correlated increases in myoplasmic [Ca2+] and force only in fibers from the susceptible patients. In contrast, caffeine administration causes correlated increases in myoplasmic [Ca2+] and force in both types of muscle, but lower concentrations were needed to do so in the fibers from the susceptible patients. The effects of halothane and caffeine were reversible. We conclude that Fura-2 can be used successfully to estimate resting levels and changes in myoplasmic [Ca2+] in human skeletal muscle.

Characterization of proteins and fatty acid composition in Galapagos fur seal milk. Occurrence of whey and casein protein polymorphisms

1. Milk proteins of the Galapagos fur seal (Arctocephalus galapagoensis) were separated adequately into whey and casein fractions using bovine milk analysis methods. 2. In samples from days 5-30 of lactation 40% of the total proteins were whey and 60% caseins; in mid-lactation, day 150, 25% were whey and 75% casein proteins. 3. Electrophoretic and isoelectric focusing patterns of fur seal whey protein differed widely from bovine patterns, whereas those of caseins were similar. 4. Polymorphisms of fur seal whey and casein proteins were noted and did not seem related to different stages of lactation. 5. C-16 and C-18 fatty acids contributed about 70% of fatty acids; 63% of the total acids in milk fat were unsaturated.