Impact of activated protein C resistance on general vascular surgical patients

Purpose: The prevalence of activated protein C resistance (APCR) and associated thrombotic morbidity among patients who undergo arterial reconstruction were investigated.Methods: Preoperative assays for functional APCR and factor V (Leiden) mutation were performed on 262 patients who underwent arterial reconstructions that consisted of cerebrovascular surgery (109), aortic or iliofemoral procedures (76), or infrainguinal bypass procedures (77). Patients were monitored for thrombotic complications during the postoperative period.Results: Depending on the stringency of the definition used, functional APCR was detected in 10.6% to 22.0% of patients tested. Factor V (Leiden) was found in 5.3% of patients. Thrombotic morbidity consisting of myocardial infarction, cerebrovascular event, or graft thrombosis occurred in 9.9% of patients, who were followed-up for a mean of 4.8 months. No significant overall correlations were found between APCR and thrombotic morbidity. Subgroup analysis revealed significant associations between functional APCR and total early postoperative thrombotic complications and early graft failure, and between factor V (Leiden) and early cerebrovascular events and late graft thrombosis (p < 0.03).Conclusions: Functional APCR is somewhat more prevalent among general vascular surgical patients than in the general population, but factor V (Leiden) is no more prevalent. APCR is not a prominent cause of thrombotic morbidity in contemporary vascular surgery. Nonetheless, it is a sufficiently important potential contributor to morbidity among some subgroups to warrant selective testing and directed therapy pending further study. (J Vasc Surg 1997;25:1054-60.)     

Analysis of magnetization transfer effects on T1-weighted spin-echo scans using a simple tissue phantom simulating gadolinium-enhanced brain lesions

The purpose of this study was to analyze the effect of several magnetization transfer (MT) pulse and T1-weighted spin-echo (SE) sequence parameters on lesion-to-background contrast, using a simple tissue phantom emulating the T1 relaxation and MT properties of gadolinium-enhanced brain lesions. Eggbeaters (Nabisco Inc., East Hanover, NJ) liquid egg product was doped with gadolinium in six concentrations from .0 to 1.0 mmol and cooked. The gadolinium-doped egg phantom and normal volunteer brains were studied using an SE sequence with TE = 20 msec and high power, pulsed, off-resonance MT saturation. The effects of MT pulse frequency offset (1,000–6,000 Hz), sequence repetition time (TR = 500–1,000 msec, with MT power held constant), and slice-select flip angle (60–120 degrees) on the magnetization transfer ratio (MTR) and the simulated lesion-to-background contrast were determined at the different “Intralesion” gadolinium concentrations. The MTR and lesion-to-background contrast of all materials were greatest at narrow MT pulse frequency offsets. There was an inverse relationship between gadolinium concentration and MTR and a positive correlation between the gadolinium concentration and lesion-to-background (L/B) contrast, a weak negative correlation between slice-select flip angle and L/B, and a negative correlation between TR and L/B. The relaxation properties and MT behavior of the egg phantom are close to that expected for enhancing brain lesions, allowing a rigorous analysis of several variables affecting lesion-to-background contrast for high MT power, T1-weighted SE sequences.     

Examining the range of normal intraindividual variability in neuropsychological test performance.

Neuropsychologists often diagnose cerebral dysfunction based, in part, on marked variation in an individual's cognitive test performance. However, little is known about what constitutes the normal range of intraindividual variation. In this study, after excluding 54 individuals with significant health problems, we derived 32 z-transformed scores from 15 tests administered to 197 adult participants in a study of normal aging. The difference between each person's highest and lowest scores was computed to assess his or her maximum discrepancy (MD). The resulting MD values ranged from 1.6 to 6.1 meaning that the smallest MD shown by any person was 1.6 standard deviations (SDs) and the largest MD shown by any person was 6.1 SDs. Sixty-six percent of participants produced MD values that exceeded 3 SDs. Eliminating each person's highest and lowest test scores decreased their MDs, but 27% of the participants still produced MD values exceeding 3. Although MD values appeared to increase with age, adjusting test scores for age, which is standard in clinical practice, did not correct for this. These data reveal that marked intraindividual variability is very common in normal adults, and underscore the need to base diagnostic inferences on clinically recognizable patterns rather than psychometric variability alone.     

Application of a 3D volume 19FMR imaging protocol for mapping oxygen tension (pO2) in perfluorocarbons at low field

A limited flip angle gradient-echo 3D volume acquisition imaging protocol for mapping partial pressure of oxygen (pO₂) in perfluorocarbon compounds (PFCs) at low field (0.14 T) is presented. The pO₂ measurement method is based on the paramagnetic effect of dissolved molecular oxygen (O₂) which reduces the PFC ¹⁹F T_1? Specific objectives related to imaging of PFCs through use of the protocol include improved image signal-to-noise characteristics and elimination of ¹⁹F chemical shift artifacts. A parametric Wiener deconvolution filtering algorithm is used for suppression of ¹⁹F chemical shift artifacts. Application of the protocol is illustrated in a series of calculated pO₂ maps of a gas equilibrated, multi-chamber phantom containing perfluorotributylamine (FC-43). The utility of the protocol is demonstrated in vivo through images of a commercially available perfluorocarbon based blood substitute emulsion containing FC-43 sequestered in the liver and spleen of a rat.     

Patients with schizophrenia previously stabilized on conventional depot antipsychotics experience significant clinical improvements following treatment with long-acting risperidone.

BACKGROUND: Conventional depot antipsychotics can provide constant pharmacologic treatment, eliminating partial compliance and reducing relapse risk. Atypical antipsychotics, have improved clinical profiles but require daily dosing, compromising their overall effectiveness. As oral risperidone provides safety and efficacy benefits over oral haloperidol, improvements may be realized by replacing conventional with atypical agents in long-acting therapy. This report examines 50-weeks of long-acting risperidone therapy in patients previously stabilized with conventional depot antipsychotics. METHODS: A multi-center, open-label study enrolled 725 patients with schizophrenia or schizoaffective disorder, judged clinically stable and maintained on stable antipsychotic doses for > or =4 weeks. Assignment by clinician judgment to receive 25-75 mg of long-acting risperidone every 2 weeks for 50 weeks followed, with performance of standard safety and efficacy assessments. Data are presented on patients receiving conventional depot antipsychotic monotherapy at study entry. RESULTS: In the 188 (25.9%) patients receiving conventional depot antipsychotic monotherapy at entry, mild-to-moderate mean (+/-S.D.) Positive and Negative Syndrome Scale (PANSS)-total scores improved significantly after receiving long-acting risperidone (64.2 +/- 18.9 to 58.2 +/- 20.3; P < 0.001). Clinical improvement of > or =20%, 40%, or 60% reduction in PANSS-total score, occurred in 52%, 34%, and 16% of patients, respectively. ESRS subjective ratings and objective physician ratings (Parkinsonism) decreased significantly (P < 0.001). CONCLUSION: Stable patients with mild, residual symptomatology treated with conventional depot antipsychotics experienced significant improvement in psychiatric and movement disorder symptomatology following 1-year of treatment with long-acting risperidone.     

Comparison of self-reports and biological measures for alcohol, tobacco, and illicit drugs consumption in psychiatric inpatients

BACKGROUND: Asking psychiatric in-patients about their drug consumption is unlikely to yield reliable results, particularly where alcohol and illicit drug use is involved. The main aim of this study was to compare spontaneous self-reports of drug use in hospitalized psychiatric patients to biological measures of same. A secondary aim was to determine which personal factors were associated with the use of tobacco, alcohol, and illicit drugs as indicated by these biological measures. METHODS: The consumption of substances was investigated using biological measures (urine cotinine, cannabis, opiates, cocaine, amphetamines and barbiturates; blood carbohydrate-deficient transferrin [CDT] and gamma-glutamyl transferase [GGT]) in 486 consecutively admitted psychiatric patients, one day following their hospitalization. Patients' self-reports of alcohol, tobacco and illicit drugs consumption were recorded. Socio-professional and familial data were also recorded. RESULTS: The results show a low correlation between biological measures and self-reported consumption of alcohol and illicit drugs. Fifty-two percent of the patients under-reported their consumption of illicit drugs (kappa=.47). Patients with schizophrenia and personality disorders were more likely to disclose their illicit drug consumption relative to patients suffering from mood disorders and alcohol dependence. Fifty-six percent of patients underreported alcohol use, as evaluated by CDT (kappa=.2), and 37% underreported when using the CDT+GGT measure as an indicator. Smoking appeared to be reported adequately. In the study we observed a strong negative correlation between cannabis use and age, a strong correlation between tobacco and cannabis use, and correlations between tobacco, cannabis and alcohol consumption. CONCLUSION: This study is the first to compare self-reports and biological measures of alcohol, tobacco and illicit drug uses in a large sample of inpatients suffering from various categories of psychiatric illnesses, allowing for cross-diagnosis comparisons.