The Effects of Age on Late Components of the ERP and Reaction Time

The effects of age on late component (N100, P200, N200, and P300) event-related potentials (ERP) and reaction time (RT) were investigated in 50 normal subjects, 18 to 70 years of age. A conventional auditory oddball paradigm was employed. An equal number of subjects, as well as an equal number of males and females, were examined in each decade. There were no significant associations found between ERP amplitude and age. A significant positive correlation was found between age and N200/P300 latency. There were no significant effects of age on RT in the overall group. However, females had slower RT and decreased P200 and N200 amplitude as compared with males. Moreover, males had significant correlations between N200 latency and RT, whereas females showed significant correlations between P300 amplitude and RT. ERP/RT effects should be further explicated between gender, as well as across age.

Assessment of uterine arterial notching as a screening test for adverse pregnancy outcome

OBJECTIVE

The objective of the study was to evaluate the screening potential of routine uterine arterial Doppler ultrasonography as a predictor of adverse pregnancy outcome.

STUDY DESIGN

All women (n = 6579) with singleton pregnancies undergoing a fetal anomaly scan at 18 to 20 weeks' gestation between January 1, 1994, and December 31, 1995, at Ninewells Hospital and Medical School were screened for the presence of uterine arterial notching. Women who had evidence of bilateral notching were rescanned at 22 to 24 weeks' gestation. Outcome measures included proteinuric hypertension, premature separation of the placenta, and birth weight z score.

RESULTS

The sensitivity and positive predictive value of uterine arterial notching as a predictor of adverse pregnancy outcomes was low. For all types of notching and disease, outcome sensitivity was never higher than 44% and positive predictive value was never higher than 27%. In contrast, the relative risk of adverse pregnancy outcome in the presence of uterine arterial notching was uniformly high for all disease outcomes (range of relative risk 3.5-30.7). Significant obstetric morbidity was seen in 57% of women with bilateral notches at 18 to 20 weeks' gestation and 72% of women with persistent bilateral notches.

CONCLUSIONS

As a screening test for adverse pregnancy outcomes, detection of uterine arterial notching is poor. Nevertheless, the presence of bilateral uterine arterial notching is associated with a significantly increased risk of adverse pregnancy outcome. In units performing routine anomaly screening, the addition of maternal uterine arterial Doppler ultrasonography may help to discriminate this small group of women at high risk.

Inguinal hernia repair: a comparison between local and general anaesthesia

BACKGROUND

A comparative analysis of outcomes of inguinal hernia repair performed under local (LA) and general anaesthesia (GA) by a single surgeon using a standardized technique of anterior transversalis repair was performed. Ninety-three cases were examined, 56 of which were cases of LA hernia repair.

METHODS

A retrospective analysis of the patient hospital record was performed with particular attention to intra-operative and post-operative analgesia requirements.

RESULTS

An overall series complication rate of 6.5% (6/93) is reported. Only one of 56 LA patients (2%) required more than 24 h of narcotic analgesic injections compared to 11% (4/37) in the GA group (P < 0.05). The mean total postoperative parenteral narcotic requirement in the LA group was 86+/-14 mg of pethidine as compared to the GA group who had a mean total requirement of 121+/-17 mg of pethidine (P > 0.08).

CONCLUSIONS

The LA infiltration technique is an effective method for inguinal hernia repair. This series demonstrates benefits in terms of length of hospital stay and a lower incidence of postoperative parenteral narcotic analgesic requirement although when post-operative parenteral narcotics were required by the LA group of patients, the difference in mean total pethidine requirement was not statistically significant.

A sensitive assay of metoprolol and its major metabolite alpha-hydroxy metoprolol in human plasma and determination of dextromethorphan and its metabolite dextrorphan in urine with high performance liquid chromatography and fluorometric detection

A reverse-phase High Performance Liquid Chromatographic (HPLC) method was developed for the analysis of metoprolol in the large number of human plasma samples obtained in in vitro-in vivo correlations (IVIVC) and bioavailability studies of extended release formulations of metoprolol tartrate. The metabolite, alpha-hydroxy metoprolol (OH-met), could also be quantified. The analytes were extracted from the plasma using solid phase columns, separated on a C-4 analytical column followed by fluorimetric detection. The linearity, precision, accuracy, stability, selectivity and ruggedness were validated for the concentration ranges of 1-400 ng ml-1 for metoprolol and 0.5-200 ng ml-1 for OH-met. The same chromatographic conditions were slightly modified to quantify dextromethorphan and its metabolite dextrorphan in urine in the concentration range 0.052-0.05 microgram ml-1 as a method for screening for fast metabolizers.

Evoked related potentials associated with and without an orienting reflex

Late component event related potentials (ERP) and concomitant electrodermal activity (EDA) measures of the orienting reflex (OR) were undertaken in 50 normal subjects. Our group recently developed a model to quantify electrodermal activity in conventional ERP paradigms (auditory oddball) with short interstimulus intervals (ISI). The method was used to classify the presence or absence of skin conductance response following each auditory target stimulus. Using a conventional paradigm in which data is traditionally averaged, single-trial target ERPs were sorted into those with a skin conductance response OR (ERP[+OR]) and those without (ERP[-OR]) an OR, and ERP sub-averages of the two groups were derived. The ERP(+OR) showed significantly larger P300 amplitudes and relatively earlier N200 and P300 latency than those of the ERP(-OR). These findings suggest that using concomitant SCR-ERP measures, separate ERP related processes can be determined, that are complementary to the traditional average measure.

Treatment with oral 3,4 diaminopyridine improves leg strength in multiple sclerosis patients: results of a randomized, double-blind, placebo-controlled, crossover trial

To examine the efficacy and toxicity of oral 3,4 diaminopyridine (DAP) in dosages up to 100 mg/day, 36 patients with multiple sclerosis (MS) enrolled in a randomized, double-blind, placebo-controlled, crossover trial. The primary outcome measure was improvement of a prospectively defined neurologic deficit, which was leg weakness in 34 patients. Secondary outcome measures included the patient's subjective response, scored manual motor testing (MMT) of leg strength, scored leg strength from videotaped motor testing (VMT), quadriceps and hamstrings strength (QMT) measured by isometric dynamometry, neuropsychological testing (NPT), ambulation index (AI), and Expanded Disability Status Scale (EDSS) score. Paresthesias and abdominal pain were common and were dose limiting in eight patients. Three patients had episodes of confusion, and one patient had a seizure while on DAP. Eight patients withdrew from the study, leaving 28 evaluable patients for the efficacy analysis. The prospectively defined neurologic deficit improved in 24 patients-22 on DAP and 2 on placebo (p = 0.0005). All improvements were in leg weakness. Subjective response and measures of leg strength and function (MMT, VMT, QMT, and AI) improved on DAP compared with placebo. Neither NPT nor EDSS scores improved. DAP treatment can induce improvements in leg strength in MS patients, but toxicity is limiting in many patients.

Simulation of the transmission of Salmonella enteritidis phage type 4 in a flock of laying hens

Simulation of disease transmission in laying flocks infected with Salmonella enteritidis phage type 4 over a 48-week egg-production period indicated that the maximum weekly incidence risk could range from 0.05 to 0.28, and the maximum proportion of culture-positive birds could range from 0.20 to 0.77 of the flock, depending on the effective contact rate. If the egg contamination proportion were 0.08, contaminated egg production could vary from a weekly maximum of 0.42 per cent to 2.24 per cent depending on the effective contact rate, but the actual rate of contamination was more important in determining the numbers of infected eggs produced. The results from previous studies suggest that this proportion could range from 0.075 to 0.25. The model produced levels of infected and immune birds similar to those reported in the literature, suggesting effective contact rates of between 2 and 4.5. There is insufficient information on transmission cycles to validate the model, but it does provide a mechanism for consolidating research findings, reviewing areas for further research, and aiding more effective planning for disease control.

Overexpression of the herpes simplex virus type 1 tegument protein VP22 increases its incorporation into virus particles

The tegument of herpes simplex virus type 1 (HSV-1) virus particles is a complex assemblage of virus proteins whose relative proportions within virions are essentially constant for a particular strain of virus. To examine the processes controlling incorporation into the tegument, we constructed a HSV-1 recombinant that expresses two copies of gene UL49, which encodes the major tegument protein VP22. One copy specifies the unmodified form of VP22 under the control of the native promoter while the second expresses an epitope-tagged version of the protein via the human cytomegalovirus immediate early promoter. In cells infected with the recombinant virus, the overall levels of VP22 synthesized were about fivefold higher than those for wild-type virus, due to the high levels of expression of tagged protein. Analysis of virus particles revealed that the amount of VP22 in the tegument was approximately two- to threefold higher in recombinant virions and L-particles than in particles produced by wild-type virus. These results provide the first evidence that, for certain proteins, the level of polypeptide synthesis can act as a controlling factor for the amount of protein incorporated into tegument.

Effect of land-based and water-based fitness programs on the cardiovascular fitness, strength and flexibility of women aged 65-75 years

The purpose of this study was to determine the effectiveness of a generalized water-based exercise program (WBE) compared to a land-based exercise program (LBE) on improving cardiorespiratory fitness, body composition, forward trunk flexion and strength measurements of elderly women aged 70 +/- 3.2 years (mean +/- SD). Forty-one healthy, sedentary women were selected to participate in the study and were randomly assigned to the LBE or WBE. The 2 groups exercised for 12 weeks, 3 times/week for 45 min. Fitness testing was done before, during and after training, and included measurements of peak aerobic power (VO2 peak), forward trunk flexion, sum of skinfolds, grip strength, curl-ups and push-ups. Between the tests performed before and after training, there were significant improvements in VO2 peak in both groups (p < 0.05) with no significant differences between the groups (p > 0.05). The LBE group also showed a significant improvement in the total number of curl-ups performed (p < 0.05). There were no significant differences in trunk forward flexion, total (right plus left) grip strength, push-ups, waist to hip ratio, sum of skinfolds or body mass index between the tests performed before and after training over time within groups or between groups (p > 0.05). The results show that general exercise interventions resulted in improvements in cardiovascular fitness (for both groups) and abdominal endurance (in the LBE only), but the two exercise programs used were not specific enough or long enough to cause improvements in muscular strength, flexibility or body composition. Furthermore, except for changes in abdominal endurance, the type of exercise venue (land vs. water) did not have a significant effect on the results obtained.

Community health workers: integral members of the health care work force

As the US health care system strives to function efficiently, encourage preventive and primary care, improve quality, and overcome nonfinancial barriers to care, the potential exists for community health workers to further these goals. Community health workers can increase access to care and facilitate appropriate use of health resources by providing outreach and cultural linkages between communities and delivery systems; reduce costs by providing health education, screening, detection, and basic emergency care; and improve quality by contributing to patient-provider communication, continuity of care, and consumer protection. Information sharing, program support, program evaluation, and continuing education are needed to expand the use of community health workers and better integrate them into the health care delivery system.

Are 'notched' uterine arterial waveforms of prognostic value for hypertensive and growth disorders of pregnancy?

In a case-control controlled study of 86 women identified as having bilaterally 'notched' uterine arterial waveform patterns at 18 weeks, the presence of bilateral 'notched' uterine arterial waveforms at that time was associated with the subsequent development of hypertension and small-for-gestational-age infants, but the predictive value was poor. For those women in whom the bilateral uterine 'notches' were observed to persist to 24 weeks, the relative risk of developing proteinuric hypertension increased 14 times, and in these women the positive predictive value for the subsequent development of hypertension increased to 58.6% when compared with their matched controls. The identification of women with persistent bilateral uterine 'notches' provides a means of identifying women at significant risk of hypertensive and growth disorders at a stage when therapeutic intervention aimed at limiting the severity of the disease and its associated complications could be commenced.

Meeting the changing health needs of women in developing countries

Demographic, epidemiological and socio-economic trends in developing countries are creating new mortality and morbidity patterns for both women and men. Women's health needs will increasingly include problems beyond reproduction, and health interventions must take into consideration the important characteristics of women's lives that affect their ability to address these problems. Meeting the changing health needs of women in developing countries will require more comprehensive health interventions guided by innovative, interdisciplinary research. A broader conceptualization of women's health needs, and the constraints and opportunities associated with meeting those needs, is necessary to avoid overly simplistic assigning of responsibility, which can lead to blaming organizations, disciplines and individuals, including women themselves, for persistent health problems and underutilization of existing services.

Treatment of postoperative hypertension after coronary artery bypass surgery. Double-blind comparison of intravenous isradipine and sodium nitroprusside

BACKGROUND

Hypertension commonly occurs after cardiac surgery and requires therapy to prevent the potentially deleterious effects.

METHODS AND RESULTS

After coronary artery bypass graft surgery (CABG), 177 patients with elevated blood pressure > or = 90 mm Hg during the initial 6-hour postsurgical period were selected for this random blinded, parallel study to receive intravenous infusions of either isradipine (n = 90) or sodium nitroprusside (n = 87). Isradipine produced a statistically significant decrease in mean arterial pressure (MAP, delta-23 mmHg) during a 90-minute treatment period. Target MAP (< or = 85 mmHg or a decrease of 10 mmHg, if baseline MAP was between 90 and 95 mmHg) was achieved in 94% of patients 30 minutes after initiation of isradipine infusion (total mean dose, 411 micrograms); target MAP was achieved in 75% of nitroprusside-treated patients (total mean dose, 1708 micrograms). The mean time to control MAP was 18 minutes for isradipine compared with 24 minutes for nitroprusside. Global smoothness in MAP control was graded on a scale of 0 (not controlled) to 5 (excellent). Approximately 76% of isradipine-treated patients received a rating of > or = 3 (mean score, 3.5); 40% of the sodium nitroprusside-treated patients achieved a score of > or = 3 (mean score, 2.0). Both isradipine and nitroprusside produced statistically significant reductions in systolic and diastolic blood pressures, a decrease in systemic vascular resistance, and increases in heart rate, cardiac index, and stroke volume index. Isradipine produced no significant decreases in pulmonary artery occlusion wedge pressure compared with nitroprusside.

CONCLUSIONS

Intravenous isradipine was effective and well tolerated in patients with hypertension after CABG and offers an additional therapeutic option to treat patients after cardiac surgery.

Optimal sampling theory: effect of error in a nominal parameter value on bias and precision of parameter estimation

The authors examined the robustness of optimal sampling theory in estimating the parameter values of two different populations of patients receiving a constant rate, half-hour intravenous infusion of theophylline. One population consisted of smokers; the other included nonsmokers. The smoking population was predicted to have a serum clearance approximately 50% greater than the nonsmokers because of an induction of the cytochrome P450 system. After an initial study to provide both patient-specific and population mean parameter values, optimal sampling strategies that were derived from each population (seven sample split designs) and the patient's seven sample and four sample design were determined. A second study was performed with an overall sampling strategy that was superset of all the above strategies. The analysis of all samples served as the reference for the parameter values. Bias and precision of the values determined with each of the optimal sampling sets (seven sample sets based on the "correct" and "wrong" populations, the patient's seven and four sample sets) were determined relative to these reference values. Irrespective of the sample set used for analysis, unbiased and precise parameter estimates, particularly of hybrid parameters were provided. With the patient's four sample set, Vss was significantly biased, but the value of (2.2%) was clinically insignificant. The authors conclude that optimal sampling theory, as implemented in this study, provides robust estimates of important pharmacokinetic parameter values, even when errors of 50% are present in the clearance of the population used to calculate the optimal sampling design.

Stability of labetalol hydrochloride with selected critical care drugs during simulated Y-site injection

The compatibility and stability of labetalol hydrochloride in combination with various critical care drugs was evaluated. Labetalol hydrochloride 1.0 mg/mL was combined in 5% dextrose injection with equal volumes of each of the following drugs: dobutamine 2.5 mg/mL (as the hydrochloride salt), dopamine hydrochloride 1.6 mg/mL, morphine sulfate 0.5 mg/mL, nitroglycerin 0.2 mg/mL, and ranitidine 0.6 mg/mL (as the hydrochloride salt). The mixtures were placed in duplicate Y-site administration sets. Visual inspection, pH determination, and high-performance liquid chromatography were performed in duplicate on samples removed at zero, two, and four hours. No change in pH or appearance occurred throughout the study. All drug concentrations remained above 90% of the initial concentration in each combination. Labetalol hydrochloride 1.0 mg/mL and dobutamine 2.5 mg/mL (as the hydrochloride salt), dopamine hydrochloride 1.6 mg/mL, morphine sulfate 0.5 mg/mL, nitroglycerin 0.2 mg/mL, or ranitidine 0.6 mg/mL (as the hydrochloride salt) in 5% dextrose injection were stable and compatible for up to four hours at 20-25 degrees C during simulated Y-site injection.

The effects of 4-aminopyridine in multiple sclerosis patients: results of a randomized, placebo-controlled, double-blind, concentration-controlled, crossover trial

Because 4-aminopyridine (AP) improves residual deficits in some multiple sclerosis (MS) patients but has a narrow toxic-to-therapeutic margin, we compared the safety and efficacy of two target peak serum concentration ranges (low: 30 to 59 ng/ml and high: 60 to 100 ng/ml). We enrolled eight MS patients with temperature-sensitive visual and motor deficits in a randomized, placebo-controlled, double-blind, crossover trial of short-term oral AP treatment. We randomized patients to a sequence of three treatments on three separate days: placebo, low serum concentration, and high serum concentration. We determined dosing to achieve the desired steady-state peak serum concentration ranges from a test dose and population pharmacokinetic parameters using bayesian estimation. Contrast sensitivity, standard neurologic examination, ratings of videotaped neurologic examinations, and quantitative strength assessment all improved with treatment, but flicker fusion frequency, visual evoked response latencies, and Expanded Disability Status Scale scores did not. All patients experienced side effects during the high-serum-concentration arm. A grand mal seizure occurred at a serum AP level of 104 ng/ml, and an acute confusional episode occurred at 114 ng/ml. AP treatment produced improvements in residual deficits in MS patients, but the occurrence of significant toxicity suggests that AP serum levels should be monitored and peak levels above 100 ng/ml should be avoided. Concentration-control methodology may be useful in testing putative treatments for other neurologic diseases.