Human leptomeningeal and cortical vascular anatomy of the cerebral cortex at 8 Tesla

PURPOSE: The purpose of this work was to describe the human leptomeningeal and cortical vascular anatomy as seen at high resolution on an 8 T UHFMRI system. METHOD: With a 1024 x 1024 matrix, axial gradient echo images of the cerebral cortex were acquired on a human volunteer at 8 T with TR 500 ms, TE 16 ms, flip angle 22.5 degrees, bandwidth 53 kHz, and slice thickness 2.84 mm. The same subject was evaluated at 1.5 T using similar parameters. The images were then reviewed in detail and compared with known cortical and leptomeningeal vascular anatomy. RESULTS: Two hundred forty micron in-plane resolution images of the human brain were acquired at 8 T without evident artifact from susceptibility distortions, RF penetration, or dielectric resonances. The CSF, gray matter, and white matter structures were well discerned. The microscopic leptomeningeal vascular anatomy was well visualized, and the course of small perforating cortical vessels could be followed from the cortical surface to the white matter junction. CONCLUSION: Initial 8 T images of the brain demonstrate detailed leptomeningeal and cortical vascular anatomy.     

Volumetric magnetic resonance imaging study of the brain in subjects with sex chromosome aneuploidies

OBJECTIVES: Cognitive impairment has been reported in people with sex chromosome aneuploides (SCAs) and it has been proposed that the presence of an extra sex chromosome may have an adverse effect on neurodevelopment. This study examines the hypothesis with structural MRI of the brain. METHODS: Thirty two subjects with SCA (XXX (n=12), XYY (n=10), and XXY (n=10)) from a birth cohort study were matched groupwise for age, parental social class, and height with normal controls (13 female, 26 male). Brain MRI, measurements of IQ, and a structured psychiatric interview were performed. RESULTS: The XXX females and XXY males had significantly smaller whole brain volumes than controls of the same phenotypic sex (p=0.003 and p相似文献   

Tremor frequency patterns in mercury vapor exposure, compared with early Parkinson's disease and essential tremor

A new portable tremometer allows determination of tremor intensities at different tremor frequencies. Based on past studies, two tremor frequency windows of similar size were chosen at 3.0-6.5 Hz and 6.6-10.0 Hz to reflect major tremor intensities in Parkinson's disease and mercury vapor poisoning, respectively. In 81 healthy controls, total tremor intensity was higher for the preferred hand and depended on age. Ten patients treated for Parkinson's disease showed substantially increased tremor intensity, especially within the low-frequency window. This pattern was also apparent in 14 patients with de novo Parkinson's disease whose overall tremor intensity was only mildly elevated. In contrast, ten patients with essential tremor had peak frequencies in both windows, and some patients had increased tremor on one side only. Sixty-three Brazilian gold traders exposed to mercury vapor showed increased tremor predominantly in the high-frequency window. Three of the gold traders had a narrower tremor peak at frequencies of 7-8 Hz. While the urine-mercury concentration was significantly associated with the current number of burning sessions per week, it did not correlate with tremor intensities. However, eight traders had a urinary mercury excretion level above 50 microg and at the same time a greatly increased average tremor intensity within the high-frequency window. These patterns were statistically significant for relative tremor intensities, but were less clear when total intensities were used. These observations suggest that the relative distribution of tremor intensities in specific frequency bands may be a valuable supplement to current diagnostic methods for subjects with mercury vapor exposure.     

Channel properties determine the transient activation kinetics of recombinant GABA(A) receptors

To understand the mechanisms underlying activation and deactivation of GABA(A) receptor (GABAR) channels, we studied the properties of an identified GABAR isoform under conditions similar to those present at central GABAergic synapses. Recombinant alpha5beta3gamma2L GABARs were expressed in L929 fibroblasts and studied using patch-clamp recording techniques. Brief application of a high GABA concentration to outside-out membrane patches elicited transient currents that resembled those reported for miniature inhibitory postsynaptic currents (mIPSCs), as well as native GABAR currents recorded under similar conditions. Characteristic of these currents was a rapid activation phase followed by a prolonged biphasic deactivation phase that far outlasted GABA application. Single-channel recordings revealed unique patterns of channel activity with two channel conductance states of 22 and 16 pS. The prolonged deactivation phase appeared to be sustained by entry into and reopening from long-lasting closures or desensitized states. Agonist affinity determined the time course of deactivation, indicating that occupied receptors drove the channel activity underlying the decay of current. The time course of deactivation was also longer at depolarized membrane potentials. The similarities between transient activation kinetics of recombinant alpha5beta3gamma2L GABARs to activation of synaptic GABARs (rapid activation and prolonged, voltage-dependent deactivation) suggest that intrinsic channel properties determine much of the response patterns of native GABARs.     

Urinary interleukin-2 monitoring during prolonged bacillus Calmette-Guerin treatment: can it predict the optimal number of instillations?

PURPOSE: In patients with superficial bladder cancer treated with a first 6-week instillation course of bacillus Calmette-Guerin (BCG) the induction pattern of urinary interleukin (IL)-2 has been described, and the levels of urinary IL-2 were associated with the clinical response to BCG treatment. We evaluated urinary IL-2 kinetics in patients with recurrent superficial bladder tumor receiving a second or third 6-week BCG instillation course. To our knowledge there have been no studies of prolonged BCG treatment and urinary cytokine responses. MATERIALS AND METHODS: Urinary IL-2 was determined in 12 patients with superficial transitional cell carcinoma of the bladder receiving a complete (6-week) second or third BCG instillation course and in 3 patients receiving 3 BCG instillations during a maintenance schedule at month 3. Urinary IL-2 was determined with an enzyme-linked immunosorbent assay using an oligoclonal system. RESULTS: Of 12 patients 10 had a urinary IL-2 positive response during the subsequent BCG course and at week 1 urinary IL-2 was already increased. Comparing the urinary IL-2 kinetics observed during a second or third with a first course, urinary IL-2 tended to be higher during the first and lower during the last weeks. If the interval between subsequent courses was short (12 months or less) significantly higher urinary IL-2 levels at weeks 1 and 2, and a lower level at week 6 were observed. CONCLUSIONS: During a repeat BCG instillation course urinary IL-2 reached a maximum at an earlier week, especially if the interval between the subsequent courses was short. Since an association between urinary IL-2 levels and response to BCG treatment during an induction course has been observed, these immunological data argue in favor of a limited number of instillations during prolonged BCG therapy which could reduce side effects as well as costs.     

A comparative study on the effects of apraclonidine and timolol on the ophthalmic blood flow velocity waveforms

Purpose: To evaluate the effects of topical timolol and apraclonidine on retrobulbar blood flow velocity waveforms in a group of healthy volunteers.Methods: Apraclonidine 1% and timolol maleate 0.5% single dose administrations were crossed over double masked in 12 healthy volunteers. The intraocular pressure measurements were followed by Doppler examination of the ophthalmic artery and the central retinal artery.Results: Intraocular pressure was reduced significantly on both treated and fellow eyes after timolol (p = 0.003, p = 0.04 respectively) and after apraclonidine (p = 0.002, p = 0.01 respectively). After apraclonidine administration end diastolic velocity, mean velocity decreased and pulsatility index increased in the ophthalmic artery of both treated and fellow eyes. Resistivity index increased and peak systolic velocity decreased only in the ophthalmic artery of treated eyes. All Doppler indices remained nonsignificant for central retinal artery of both eyes.After timolol administration there were no significant changes of the Doppler indices in the ophthalmic artery and central retinal artery of the treated and fellow eyes.Conclusion: Topical timolol and apraclonidine significantly reduced the intraocular pressure. Single dose administration of apraclonidine 1% increased the vascular impedance distal to the ophthalmic artery. On the other hand, timolol 0.5% had no effect on vascular impedance.     

The comparative validity of eleven alcoholism typologies

OBJECTIVE: This study directly compared the clinical validity of 11 empirically defined alcoholism typologies to determine whether some typologies are clinically more valid than others. METHOD: A sample of 360 hospitalized alcoholic men were extensively evaluated at entry into the study and again 1 year later. Twenty-three measures of clinical validity were employed; 15 were postdictive and 8 were predictive. Postdictive retrospective measures obtained at entry into the study included family history, age of onset and lifetime course characteristics associated with alcoholism severity, general psychopathology and psychosocial functioning. Predictive outcome measures drawn from information obtained during the 1-year follow-up included: abstinence, alcoholism severity and clinician ratings of outcome. The measures were subjected to various statistical analyses, including factor analysis. RESULTS: We found that all of the alcoholism typologies met at least 7 of the 23 a priori measures of clinical validity. The correlations between these conceptually and methodologically disparate typologies were often striking. Exploratory factor analysis, which explained 35% of the variance, suggested three possible underlying dimensions to account for the overlap among typologies: (1) age and its correlates, including age-of-alcoholism onset; (2) "pure" alcoholism versus psychiatrically heterogeneous alcoholism that encompassed antisocial personality disorder; and (3) current severity of psychiatric distress, impairment and dysfunction. CONCLUSIONS: No single method of subtyping alcoholics clearly emerged as superior. All demonstrated some degree of predictive and postdictive clinical validity. Most methods of subtyping correlated positively with each other at moderate, but typically significant, levels.     

Sulfonium salts as derivatizing agents. 3. Quantitation of the cocaine metabolite benzoylecgonine in urine using gas chromatography with ion-pair extraction/on-column alkylation

Recent studies have demonstrated the utility of quantitative assays for benzoylecgonine in assessing the efficacy of cocaine-dependence-treatment programs to determine if the amount of cocaine consumed has been reduced. We describe a simple gas chromatographic method for determining benzoylecgonine concentrations in urine. BZE is extracted from urine as an ion pair with tri-n-propylsulfonium ion. Injection into the heated injection port of the gas chromatograph results in thermal conversion of the ion pair to the n-propyl ester of BZE. Using the structural analogue of BZE, m-toluylecgonine, as the internal standard, the analysis is carried out on a (5% phenyl)methylpolysiloxane capillary column with nitrogen-phosphorus detection. There was a good correlation between BZE concentrations determined by gas chromatography-mass spectrometry and concentrations determined by the method described in this paper. Application to cocaine-dependence-treatment programs is discussed.     

Native Hawaiian Birth Weight and Infant Mortality: Is Birth in Hawai'i Protective?

PURPOSE OF THE PAPER: This study provides baseline information on the characteristics of Native Hawaiian mothers and the health status of their infants, comparing residents of Hawaii with those of the continental U.S. The impact of Hawaii residence on low birth weight and infant mortality among Native Hawaiians is assessed. SUMMARY OF METHODS UTILIZED: Data from the National Center for Health Statistics 1983­1987 Linked U.S. Live Birth and Infant Death file were used to examine parental characteristics, prenatal care use and infant outcomes using chi­square and logistic regression procedures. PRINCIPAL FINDINGS: Despite a higher sociodemographic risk profile among Hawaii resident mothers, preterm birth, low and very low birth weight percentages were similar. Continental infants had significantly highter percentages of very pre­term birth and macrosomia. Mortality rates in both the neonatal and post­neonatal periods, and for SIDS and perinatal causes were elevated among continental infants. Hawaii residence had a borderline protective effect on infant mortality, wehn sociodemographic and prenatal care differences were controlled. CONCLUSIONS: This study suggests a possibly protective effect of Hawaii residence on the health of Native Hawaiian infants during the period of following employer­mandated health insurance coverage but before the initiation of "gap­group" coverage and the Native Hawaiian Health Care Systems in Hawaii. RELEVANCE TO ASIAN PACIFIC ISLANDER AMERICAN POPULATIONS. This is the first report documenting the sociodemographic and health status of the growing number of Native Hawaiian mothers and their infants residing outside of Hawaii. Expanded health insurance coverage and culturally appropriate and accessible health care may contribute to improved infant health status in Hawaii. Their absence, along with possible barriers of sociocultural isolation, may account for the poorer than expected outcomes of continental infants and predict a widening gap between them and their counterparts in Hawaii. A follow­up study of the health status of Native Hawaiian mothers and infants, and their access to appropriate care in Hawaii and thei continental U.S. is recommended.