Prognostic Factors of Stroke-Like Migraine Attacks after Radiation Therapy (SMART) Syndrome

BACKGROUND AND PURPOSE

Prognostic factors of stroke-like migraine attacks after radiation therapy (SMART) syndrome have not been fully explored. This study aimed to assess clinical and imaging features to predict the clinical outcome of SMART syndrome.

MATERIALS AND METHODS

We retrospectively reviewed the clinical manifestations and imaging findings of 20 patients with SMART syndrome (median age, 48 years; 5 women) from January 2016 to January 2020 at 4 medical centers. Patient demographics and MR imaging features at the time of diagnosis were reviewed. This cohort was divided into 2 groups based on the degree of clinical improvement (completely versus incompletely recovered). The numeric and categoric variables were compared as appropriate.

RESULTS

There were statistically significant differences between the completely recovered group (n = 11; median age, 44 years; 2 women) and the incompletely recovered group (n = 9; median age, 55 years; 3 women) in age, months of follow-up, and the presence of steroid treatment at diagnosis (P = .028, .002, and .01, respectively). Regarding MR imaging features, there were statistically significant differences in the presence of linear subcortical WM susceptibility abnormality, restricted diffusion, and subcortical WM edematous changes in the acute SMART region (3/11 versus 8/9, P = .01; 0/11 versus 4/9, P = .026; and 2/11 versus 7/9, P = .022, respectively). Follow-up MRIs showed persistent susceptibility abnormality (11/11) and subcortical WM edematous changes (9/9), with resolution of restricted diffusion (4/4).

CONCLUSIONS

Age, use of steroid treatment at the diagnosis of SMART syndrome, and MR imaging findings of abnormal susceptibility signal, restricted diffusion, and subcortical WM change in the acute SMART region can be prognostic factors in SMART syndrome.

Pretreatment ADC Histogram Analysis as a Prognostic Imaging Biomarker for Patients with Recurrent Glioblastoma Treated with Bevacizumab: A Systematic Review and Meta-analysis

BACKGROUND

The mean ADC value of the lower Gaussian curve (ADC_L) derived from the bi-Gaussian curve-fitting histogram analysis has been reported as a predictive/prognostic imaging biomarker in patients with recurrent glioblastoma treated with bevacizumab; however, its systematic summary has been lacking.

PURPOSE

We applied a systematic review and meta-analysis to investigate the predictive/prognostic performance of ADC_L in patients with recurrent glioblastoma treated with bevacizumab.

DATA SOURCES

We performed a literature search using PubMed, Scopus, and EMBASE.

STUDY SELECTION

A total of 1344 abstracts were screened, of which 83 articles were considered potentially relevant. Data were finally extracted from 6 studies including 578 patients.

DATA ANALYSIS

Forest plots were generated to illustrate the hazard ratios of overall survival and progression-free survival. The heterogeneity across the studies was assessed using the Cochrane Q test and I² values.

DATA SYNTHESIS

The pooled hazard ratios for overall survival and progression-free survival in patients with an ADC_L lower than the cutoff values were 1.89 (95% CI, 1.53-2.31) and 1.98 (95% CI, 1.54-2.55) with low heterogeneity among the studies. Subgroup analysis of the bevacizumab-free cohort showed a pooled hazard ratio for overall survival of 1.20 (95% CI, 1.08-1.34) with low heterogeneity.

LIMITATIONS

The conclusions are limited by the difference in the definition of recurrence among the included studies.

CONCLUSIONS

This systematic review with meta-analysis supports the prognostic value of ADC_L in patients with recurrent glioblastoma treated with bevacizumab, with a low ADC_L demonstrating decreased overall survival and progression-free survival. On the other hand, the predictive role of ADC_L for bevacizumab treatment was not confirmed.

Diagnostic Role of Diffusion-Weighted and Dynamic Contrast-Enhanced Perfusion MR Imaging in Paragangliomas and Schwannomas in the Head and Neck

BACKGROUND AND PURPOSE

Distinguishing schwannomas from paragangliomas in the head and neck and determining succinate dehydrogenase (SDH) mutation status in paragangliomas are clinically important. We aimed to assess the clinical usefulness of DWI and dynamic contrast-enhanced MR imaging in differentiating these 2 types of tumors, as well as the SDH mutation status of paragangliomas.

MATERIALS AND METHODS

This retrospective study from June 2016 to June 2020 included 42 patients with 15 schwannomas and 27 paragangliomas (10 SDH mutation-positive and 17 SDH mutation-negative). ADC values, dynamic contrast-enhanced MRI parameters, and tumor imaging characteristics were compared between the 2 tumors and between the mutation statuses of paragangliomas as appropriate. Multivariate stepwise logistic regression analysis was performed to identify significant differences in these parameters.

RESULTS

Fractional plasma volume (P ≤ .001), rate transfer constant (P = .038), time-to-maximum enhancement (P < .001), maximum signal-enhancement ratio (P < .001) and maximum concentration of contrast agent (P < .001), velocity of enhancement (P = .002), and tumor characteristics including the presence of flow voids (P = .001) and enhancement patterns (P = .027) showed significant differences between schwannomas and paragangliomas, though there was no significant difference in ADC values. In the multivariate logistic regression analysis, fractional plasma volume was identified as the most significant value for differentiation of the 2 tumor types (P = .014). ADC values were significantly higher in nonhereditary than in hereditary paragangliomas, while there was no difference in dynamic contrast-enhanced MR imaging parameters.

CONCLUSIONS

Dynamic contrast-enhanced MR imaging parameters show promise in differentiating head and neck schwannomas and paragangliomas, while DWI can be useful in detecting SDH mutation status in paragangliomas.

Assessment of MR Imaging and CT in Differentiating Hereditary and Nonhereditary Paragangliomas

BACKGROUND AND PURPOSE

Head and neck paragangliomas have been reported to be associated with mutations of the succinate dehydrogenase enzyme family. The aim of this study was to assess whether radiologic features could differentiate between paragangliomas in the head and neck positive and negative for the succinate dehydrogenase mutation.

MATERIALS AND METHODS

This single-center retrospective review from January 2015 to January 2020 included 40 patients with 48 paragangliomas (30 tumors positive for succinate dehydrogenase mutation in 23 patients and 18 tumors negative for the succinate dehydrogenase mutation in 17 patients). ADC values and tumor characteristics on CT and MR imaging were evaluated by 2 radiologists. Differences between the 2 cohorts in the diagnostic performance of ADC and normalized ADC (ratio to ADC in the medulla oblongata) values were evaluated using the independent samples t test. P < .05 was considered significant.

RESULTS

ADC_mean (1.07 [SD, 0.25]/1.04 [SD, 0.12] versus 1.31 [SD, 0.16]/1.30 [SD, 0.20]× 10^-3 mm²/s by radiologists 1 and 2; P < .001), ADC_maximum (1.49 [SD, 0.27]/1.49 [SD, 0.20] versus 2.01 [SD, 0.16]/1.87 [SD, 0.20] × 10^-3 mm²/s; P < .001), normalized ADC_mean (1.40 [SD, 0.33]/1.37 [SD, 0.16] versus 1.73 [SD, 0.22]/1.74 [SD, 0.27]; P < .001), and normalized ADC_maximum (1.95 [SD, 0.37]/1.97 [SD, 0.27] versus 2.64 [SD, 0.22]/2.48 [SD, 0.28]; P < .001) were significantly lower in succinate dehydrogenase mutation-positive than mutation-negative tumors. ADC_minimum, normalized ADC_minimum, and tumor characteristics were not statistically significant.

CONCLUSIONS

ADC is a promising imaging biomarker that can help differentiate succinate dehydrogenase mutation-positive from mutation-negative paragangliomas in the head and neck.

MRI Findings of Immune Checkpoint Inhibitor-Induced Hypophysitis: Possible Association with Fibrosis

BACKGROUND AND PURPOSE

Hypophysitis is one of the well-known adverse effects of immune checkpoint inhibitors. Immune checkpoint inhibitor-induced hypophysitis frequently causes irreversible hypopituitarism, which requires long-term hormone replacement. Despite the high frequency and clinical significance, characteristic MR imaging findings of immune checkpoint inhibitor-induced hypophysitis have not been established. In the present study, we aimed to review and extract the MR imaging features of immune checkpoint inhibitor-induced hypophysitis.

MATERIALS AND METHODS

This retrospective international multicenter study comprised 20 patients with melanoma who were being treated with immune checkpoint inhibitors and clinically diagnosed with immune checkpoint inhibitor-induced hypophysitis. Three radiologists evaluated the following MR imaging findings: enlargement of the pituitary gland and stalk; homogeneity of enhancement of the pituitary gland; presence/absence of a well-defined poorly enhanced area and, if present, its location, shape, and signal intensity in T2WI; and enhancement pattern in contrast-enhanced dynamic MR imaging. Clinical symptoms and hormone levels were also recorded.

RESULTS

Enlargement of the pituitary gland and stalk was observed in 12 and 20 patients, respectively. Nineteen patients showed poorly enhanced lesions (geographic hypoenhancing lesions) in the anterior lobe, and 11 of these lesions showed hypointensity on T2WI. Thyrotropin deficiency and corticotropin deficiency were observed in 19/20 and 12/17 patients, respectively, which persisted in 12/19 and 10/12 patients, respectively, throughout the study period.

CONCLUSIONS

Pituitary geographic hypoenhancing lesions in the anterior lobe of the pituitary gland are characteristic and frequent MR imaging findings of immune checkpoint inhibitor-induced hypophysitis. They reflect fibrosis and are useful in distinguishing immune checkpoint inhibitor-induced hypophysitis from other types of hypophysitis/tumors.

Retrospective, dual-centre review of imaging findings in neurosarcoidosis at presentation: prevalence and imaging sub-types

AIM

To assess the prevalence of various imaging manifestations in neurosarcoidosis (NS) patients at presentation and to explore if specific imaging findings may cluster in different sub-groups.

MATERIALS AND METHODS

A retrospective, dual-institution, systematic imaging review was undertaken of the magnetic resonance imaging (MRI) findings in 100 consecutive NS patients who presented over a 15-year period. Clustering analysis (k-mode) was performed to evaluate co-occurrence of imaging findings.

RESULTS

Non-enhancing white matter (NEWM) lesions were the most common imaging abnormality (56%), followed by leptomeningeal (47%) and pachymeningeal (32%) involvement. Other common manifestations included cranial nerve involvement (30%), parenchymal granulomas (27%), hypothalamic-pituitary-adrenal axis involvement (26%), and hydrocephalus (14%). Additionally, a higher prevalence of perivascular enhancement (23%), cerebrovascular events (including ischaemic and haemorrhagic events; 17%), and ependymal involvement (20%) were noted than recognised previously. Additional k-mode analysis was performed to explore underlying disease sub-clusters. This was evaluated for clusters varying between two though five (k=2-5). For k=4, the analysis revealed that the imaging findings may possibly be divided into disease sub-sets of four groups, each with varying distribution of imaging manifestations and clinical manifestations.

CONCLUSION

Overall, NEWM lesions and meningeal involvement are the most common imaging manifestations of NS. The prevalence of perivascular enhancement, cerebrovascular events, and ependymal involvement is likely higher than reported previously. Additionally, different imaging findings in NS may cluster together and imaging subtypes in NS possibly exist.

Effect of combined bifidobacteria supplementation and resistance training on cognitive function, body composition and bowel habits of healthy elderly subjects

Physical exercise exerts favourable effects on brain health and quality of life of the elderly; some of these positive health effects are induced by the modulation of microbiota composition. We therefore conducted a randomised, double blind, placebo-controlled trial that assessed whether a combination of Bifidobacterium spp. supplementation and moderate resistance training improved the cognitive function and other health-related parameters in healthy elderly subjects. Over a 12-week period, 38 participants (66-78 years) underwent resistance training and were assigned to the probiotic Bifidobacterium supplementation (n=20; 1.25×10¹⁰ cfu each of Bifidobacterium longum subsp. longum BB536, B. longum subsp. infantis M-63, Bifidobacterium breve M-16V and B. breve B-3) or the placebo (n=18) group. At baseline and at 12 weeks, we assessed the cognitive function, using the Japanese version of the Montreal Cognitive Assessment instrument (MoCA-J); modified flanker task scores; depression-anxiety scores; body composition; and bowel habits. At 12 weeks, the MoCA-J scores showed a significant increase in both the groups, while the flanker task scores of the probiotic group increased more significantly than those of the placebo group (0.35±0.9 vs -0.29±1.1, P=0.056). Only the probiotic group showed a significant decrease in the depression-anxiety scores (5.2±6.3 to 3.4±5.5, P=0.012) and body mass index (24.0±2.8 to 23.5±2.8 kg/m², P<0.001), with a significant increase in the defecation frequency (5.3±2.3 to 6.4±2.3 times/5 days, P=0.023) at 12 weeks. Thus, in healthy elderly subjects, combined probiotic bifidobacteria supplementation and moderate resistance training may improve the mental condition, body weight and bowel movement frequency.

Surface electromyographic evaluation of the neuromuscular activation of the inspiratory muscles during progressively increased inspiratory flow under inspiratory-resistive loading

This study aimed to evaluate neuromuscular activation in the scalene and sternocleidomastoid muscles using surface electromyography (EMG) during progressively increased inspiratory flow, produced by increasing the respiratory rate under inspiratory-resistive loading using a mask ventilator. Moreover, we attempted to identify the EMG inflection point (EMG^IP) on the graph, at which the root mean square (RMS) of the EMG signal values of the inspiratory muscles against the inspiratory flow velocity acceleration abruptly increases, similarly to the EMG anaerobic threshold (EMG^AT) reported during incremental-resistive loading in other skeletal muscles. We measured neuromuscular activation of healthy male subjects and found that the inspiratory flow velocity increased by approximately 1.6-fold. We successfully observed an increase in RMS that corresponded to inspiratory flow acceleration with ρ ≥ 0.7 (Spearman's rank correlation) in 17 of 27 subjects who completed the experimental protocol. To identify EMG^IP, we analyzed the fitting to either a straight or non-straight line related to the increasing inspiratory flow and RMS using piecewise linear spline functions. As a result, EMG^IP was identified in the scalene and sternocleidomastoid muscles of 17 subjects. We believe that the identification of EMG^IP in this study infers the existence of EMG^AT in inspiratory muscles. Application of surface EMG, followed by identification of EMG^IP, for evaluating the neuromuscular activation of respiratory muscles may be allowed to estimate the signs of the respiratory failure, including labored respiration, objectively and non-invasively accompanied using accessory muscles in clinical respiratory care.

Cerebrovascular Manifestations of Neurosarcoidosis: An Underrecognized Aspect of the Imaging Spectrum

Involvement of the central nervous system by sarcoidosis, also referred to as neurosarcoidosis, is seen clinically in about 5% of patients with systemic disease. CNS involvement most frequently affects the leptomeninges and cranial nerves, though the ventricular system, brain parenchyma, and pachymeninges may also be involved. Even though the involvement of the intracranial vascular structures is well-known on postmortem studies, there is scant literature on imaging manifestations secondary to the vessel wall involvement, being confined mostly to isolated case reports and small series. The authors present a review of various cerebrovascular manifestations of neurosarcoidosis, along with a brief synopsis of the existing literature.

Role of the Apparent Diffusion Coefficient as a Predictor of Tumor Progression in Patients with Chordoma

BACKGROUND AND PURPOSE

Diffusion-weighted imaging may aid in distinguishing aggressive chordoma from nonaggressive chordoma. This study explores the prognostic role of the apparent diffusion coefficient in chordomas.

MATERIALS AND METHODS

Sixteen patients with residual or recurrent chordoma were divided postoperatively into those with an aggressive tumor, defined as a growing tumor having a doubling time of <1 year, and those with a nonaggressive tumor on follow-up MR images. The ability of the ADC to predict an aggressive tumor phenotype was investigated by receiver operating characteristic analysis. The prognostic role of ADC was assessed using a Kaplan-Meier curve with a log-rank test.

RESULTS

Seven patients died during a median follow-up of 48 months (range, 4-126 months). Five of these 7 patients were in the aggressive tumor group, and 2 were in the nonaggressive tumor group. The mean ADC was significantly lower in the aggressive tumor group than in the nonaggressive tumor group (P = .002). Receiver operating characteristic analysis showed that a cutoff ADC value of 1.494 × 10^-3 × mm²/s could be used to diagnose aggressive tumors with an area under the curve of 0.983 (95% CI, 0.911-1.000), a sensitivity of 1.000 (95% CI, 0.541-1.000), and a specificity of 0.900 (95% CI, 0.555-0.998). Furthermore, a cutoff ADC of ≤1.494 × 10^-3 × mm²/s was associated with a significantly worse prognosis (P = .006).

CONCLUSIONS

Lower ADC values could predict tumor progression in postoperative chordomas.

Atypical Presentations of Intracranial Hypotension: Comparison with Classic Spontaneous Intracranial Hypotension

BACKGROUND AND PURPOSE

Atypical clinical presentations of spontaneous intracranial hypotension include obtundation, memory deficits, dementia with frontotemporal features, parkinsonism, and ataxia. The purpose of this study was to compare clinical and imaging features of spontaneous intracranial hypotension with typical-versus-atypical presentations.

MATERIALS AND METHODS

Clinical records and neuroimaging of patients with spontaneous intracranial hypotension from September 2005 to August 2014 were retrospectively evaluated. Patients with classic spontaneous intracranial hypotension (n = 33; mean age, 41.7 ± 14.3 years) were compared with those with intracranial hypotension with atypical clinical presentation (n = 8; mean age, 55.9 ± 14.1 years) and 36 controls (mean age, 41.4 ± 11.2 years).

RESULTS

Patients with atypical spontaneous intracranial hypotension were older than those with classic spontaneous intracranial hypotension (55.9 ± 14.1 years versus 41.7 ± 14.3 years; P = .018). Symptom duration was shorter in classic compared with atypical spontaneous intracranial hypotension (3.78 ± 7.18 months versus 21.93 ± 18.43 months; P = .015). There was no significant difference in dural enhancement, subdural hematomas, or cerebellar tonsil herniation. Patients with atypical spontaneous intracranial hypotension had significantly more elongated anteroposterior midbrain diameter compared with those with classic spontaneous intracranial hypotension (33.6 ± 2.9 mm versus 27.3 ± 2.9 mm; P < .001) and shortened pontomammillary distance (2.8 ± 1 mm versus 5.15 ± 1.5 mm; P < .001). Patients with atypical spontaneous intracranial hypotension were less likely to become symptom-free, regardless of treatment, compared with those with classic spontaneous intracranial hypotension (χ(2) = 13.99, P < .001).

CONCLUSIONS

In this sample of 8 patients, atypical spontaneous intracranial hypotension was a more chronic syndrome compared with classic spontaneous intracranial hypotension, with more severe brain sagging, lower rates of clinical response, and frequent relapses. Awareness of atypical presentations of spontaneous intracranial hypotension is paramount.

Pyogenic and non-pyogenic spinal infections: emphasis on diffusion-weighted imaging for the detection of abscesses and pus collections

The incidence of spinal infections has increased in the past two decades, owing to the increasing number of elderly patients, immunocompromised conditions, spinal surgery and instrumentation, vascular access and intravenous drug use. Conventional MRI is the gold standard for diagnostic imaging; however, there are still a significant number of misdiagnosed cases. Diffusion-weighted imaging (DWI) with a b-value of 1000 and apparent diffusion coefficient (ADC) maps provide early and accurate detection of abscess and pus collection. Pyogenic infections are classified into four types of extension based on MRI and DWI findings: (1) epidural/paraspinal abscess with spondylodiscitis, (2) epidural/paraspinal abscess with facet joint infection, (3) epidural/paraspinal abscess without concomitant spondylodiscitis or facet joint infection and (4) intradural abscess (subdural abscess, purulent meningitis and spinal cord abscess). DWI easily detects abscesses and demonstrates the extension, multiplicity and remote disseminated infection. DWI is often a key image in the differential diagnosis. Important differential diagnoses include epidural, subdural or subarachnoid haemorrhage, cerebrospinal fluid leak, disc herniation, synovial cyst, granulation tissue, intra- or extradural tumour and post-surgical fluid collections. DWI and the ADC values are affected by susceptibility artefacts, incomplete fat suppression and volume-averaging artefacts. Recognition of artefacts is essential when interpreting DWI of spinal and paraspinal infections. DWI is not only useful for the diagnosis but also for the treatment planning of pyogenic and non-pyogenic spinal infections.

"Dazed and diffused": making sense of diffusion abnormalities in neurologic pathologies

To review diffusion abnormalities seen in diffusion-weighted MRI in neurological pathologies. We examine the clinical significance of the abnormalities in a broad spectrum of neurological diseases and highlight our current understanding of their causes. Diffusion abnormalities seen on diffusion-weighted MRI can play an important role in the diagnosis and follow-up of a broad spectrum of neurological diseases. A thorough understanding of the appearance and significance of these abnormalities is critical in patient management.

Adiponectin gene single-nucleotide polymorphisms and treatment response to obesity

BACKGROUND

In the adiponectin gene polymorphisms, single-nucleotide polymorphism (SNP)-45 and SNP276 have reportedly been associated with obesity, Type 2 diabetes, and other features of metabolic syndrome.

AIM

Whether these adiponectin SNP affect obesity-related parameters during caloric restriction in obese subjects.

SUBJECTS AND METHODS

Thirty- two obese Japanese women were treated by meal replacement with a low calorie diet for 8 weeks and asked to maintain their habitual lifestyle. Obesity-related parameters were measured before and after the treatment period. We determined four SNP (T45G, I164T, G276T, and C-11377G) using a fluorescent allele-specific DNA primer assay systemand FRET probe assay system.

RESULTS

After the treatment, the extent of decrease in waist circumference was greater in the subjects with the G/G or G/T genotype of SNP276 than in those with the T/T genotype (p=0.026). As for SNP45, the extent of decrease in triglyceride levels was greater in the subjects with the T/T genotype than in those with the T/G genotype (p=0.003). For SNP-11377, the extent of decrease in systolic blood pressure and fasting plasma glucose was greater in the subjects with the C/G or G/G genotype than in those with the C/C genotype (p=0.044).

CONCLUSION

Our findings indicate that each SNP in the adiponectin gene might modify the change in obesity-related parameters during meal replacement with a low calorie diet.

Occipital intradiploic CSF pseudocyst: an unusual complication of a ventriculoperitoneal shunt malfunction

We report a rare and unique complication of ventriculoperitoneal (VP) shunt malfunction. A progressively expansile, CSF-containing occipital intradiploic cyst developed in a 15-year-old boy at the site of cystoperitoneal shunt draining a Dandy-Walker cyst; the shunt was placed when the boy was 4 years old. A proposed pathogenesis of the lesion is discussed.

Effects of acute exercise on visual reaction time

We examined the effects of acute exercise on reaction time to visual stimuli presented in the central portion and periphery of the visual field. Twelve participants performed reaction time tasks at rest and during cycling at 65 % peak oxygen uptake in two visual conditions. We used circular black-and-white checkerboard patterns as visual stimuli. The participants were asked to respond as quickly as possible to pattern reversal of the visual stimulus by releasing a response button. Reaction time was fractionated into Premotor time and Motor time. Premotor time in the peripheral condition significantly increased (p < 0.025) during exercise (mean +/- SE; 195.9 +/- 7.9 ms) from that at rest (183.7 +/- 6.8 ms). Premotor time in the central condition did not differ between at rest (185.3 +/- 7.6 ms) and during exercise (188.4 +/- 6.6 ms). These data suggest that the ability to respond to visual stimuli presented in the periphery of the visual field is vulnerable to moderate to severe exercise, as compared with the ability to respond to visual stimuli presented in the central portion of the visual field. An exercise-induced increase in arousal level and a consequent narrowing of attentional focus would explain the present results.

Rathke's cleft cysts: differentiation from other cystic lesions in the pituitary fossa by use of single-shot fast spin-echo diffusion-weighted MR imaging

OBJECTIVE

Rathke's cleft cysts are often difficult to differentiate from other sellar cystic lesions using conventional MR imaging. The purpose of this study was to investigate the usefulness of single-shot fast spin-echo (SSFSE) diffusion-weighted MR imaging (DWI) in the diagnosis of a Rathke's cleft cyst.

PATIENTS AND METHODS

We examined retrospectively 29 patients with a histologically verified sellar or suprasellar lesion containing a fluid component; 12 patients had a Rathke's cleft cyst, 6 patients a craniopharyngioma, 5 patients a haemorrhagic pituitary adenoma, and 6 patients a cystic pituitary adenoma). Several regions of interest (ROIs) for apparent diffusion coefficient (ADC) measurements were identified in the fluid components of the lesions. For comparison, ADC values were normalized using a relative ADC (rADC), which was determined by dividing the ADC values of lesions by those of normal white matter and expressing the quotient as a ratio.

RESULTS

SSFSE provides diffusion-weighted images without significant susceptibility artifacts. DWI-SSFSE revealed Rathke's cleft cysts as hypointense relative to the normal brain parenchyma in all cases. The mean value of ADC for Rathke's cleft cysts was 2.12 x 10(-3) mm(2)/sec. Both the ADC and relative ADC of the Rathke's cleft cysts were significantly increased compared to those of the cystic components of craniopharyngiomas and haemorrhagic components of pituitary adenomas in the subacute phase (P < 0.05). There was not a statistically significant difference between Rathke's cleft cysts and cystic components of pituitary adenomas (P < 0.05).

CONCLUSIONS

DWI-SSFSE with ADC values provides objective information in the differential diagnosis of Rathke's cleft cysts from other sellar cystic lesions. In addition, DWI-SSFSE with ADC values is useful for differentiating Rathke's cleft cysts from craniopharyngiomas and haemorrhagic pituitary adenomas.

Effect of aging on carotid artery stiffness and baroreflex sensitivity during head-out water immersion in man

To examine the possible age-related blood pressure (BP) deregulation in response to central hypervolemia, we measured spontaneous baroreflex sensitivity (SBRS), carotid arterial compliance (CC), and R-R interval coefficient of variation (RRICV) during basal and thermoneutral resting head-out-of-water immersion (HOWI) in 7 young (YG = 24.0 +/- 0.8 years) and 6 middle-aged/older (OL = 59.3 +/- 1.3 years) healthy men. Compared with basal conditions (YG = 19.6 +/- 4.0 vs OL = 6.1 +/- 1.5 ms/mmHg, P < 0.05), SBRS remained higher in YG than OL during rest HOWI (YG = 23.6 +/- 6.6 vs OL = 9.3 +/- 2.1 ms/mmHg, P < 0.05). The RRICV was significantly different between groups (YG = 6.5 +/- 1.4 vs OL = 2.8 +/- 0.4%, P < 0.05) under HOWI. The OL group had no increase in CC, but a significant increase in systolic BP (basal = 115.3 +/- 4.4 vs water = 129.3 +/- 5.3 mmHg, P < 0.05) under HOWI. In contrast, the YG group had a significant increase in CC (basal = 0.16 +/- 0.01 vs water = 0.17 +/- 0.02 mm(2)/mmHg, P < 0.05) with no changes in systolic BP. SBRS was positively related to CC (r = 0.58, P < 0.05 for basal vs r = 0.62, P < 0.05 for water). Our data suggest that age-related vagal dysfunction and reduced CC may be associated with SBRS differences between YG and OL groups, and with BP elevation during HOWI in healthy older men.

Effect of physical activity on autonomic nervous system function in lean and obese children

OBJECTIVE

The autonomic nervous system (ANS) is a key factor in the regulation of energy balance and body fat storage;however, to what extent the physical activity during the childhood years contributes to variations in ANS function is still unclear. The present study was designed to investigate the ANS activity in lean and obese children, focusing on the differences in physical activity levels.

SUBJECTS

This study was performed on 1080 school children initially recruited to the present study. In all, 24 physically active and 24 inactive obese children (> or =120% of the standard body weight) were chosen as samples. Then, 24 lean-active and 24 lean-inactive children, who were matched individually in age, gender, height, and the amount of sports activity, were carefully selected from the remaining children.

MEASUREMENTS

Physical activity was classified as the frequency of participation in after-school sports activities (active; > or =3 times per week, inactive; nothing). The ANS activities were measured during the resting condition by means of heart rate (HR) variability power spectral analysis, which enables us to identify separate frequency components, that is, low frequency (LF; 0.03-0.15 Hz), reflecting mixed sympathetic (SNS) and parasympathetic nervous system (PNS) activity, high frequency (HF; 0.15-0.5 Hz), mainly associated with PNS activity, and total power (TP; 0.03-0.5 Hz), evaluating the overall ANS activity. The spectral powers were log transformed for statistical testing.

RESULTS

The lean-active group demonstrated lower resting HR as well as significantly higher TP, LF, and HF powers compared to the remaining groups. In contrast, the obese-inactive group showed significantly lower TP (P<0.05 vs the remaining groups), LF (P<0.05 vs the lean groups), and HF power (P<0.05 vs the lean groups), respectively. The obese-active and lean-inactive groups were nearly identical in all spectral parameters. The correlation analysis revealed that TP among 48 inactive children was significantly and negatively associated with the percentage of body fat (r=-0.53, P<0.001); however, such correlation among 48 active children was modest (r=-0.33, P=0.02).

CONCLUSION

Our data suggest that obese children possess reduced sympathetic as well as parasympathetic nervous activities as compared to lean children who have similar physical activity levels. Such autonomic reduction, associated with the amount of body fat in inactive state, might be an etiological factor of onset or development of childhood obesity. On the other hand, regular physical activities could contribute to enhance the overall ANS activity in both lean and obese children. These findings further imply that regular physical activity might be effective in preventing and treating obesity beginning in the childhood.

Protective effect of sesamin administration on exercise-induced lipid peroxidation

To investigate the mechanism of antioxidative effects of sesamin in vivo, 32 male ddY mice were administered with 10 mg/kg or 100 mg/kg of sesamin (S10, S100), 100 mg/kg of vitamin E (VE100) or control sample (C). They were subjected to 30 min of swimming exercise 2 h after the sample administration by using a new forced-swimming apparatus, i. e. an adjustable-current swimming pool. Exercise resulted in a significant increase in plasma lipid peroxides (LPO) in C and VE100 (p < 0.01), but not in S10 and S100. S100 showed significantly higher total glutathione peroxidase activity and glutathione S-transferase activity in liver compared to C (p < 0.05). In conclusion, sesamin may enhance LPO degradation in the liver resulting in the strong protective effects against exercise-induced plasma lipid peroxidation.

Motor unit activation patterns during isometric, concentric and eccentric actions at different force levels

Motor unit activation patterns were studied during four different force levels of concentric and eccentric actions. Eight male subjects performed concentric and eccentric forearm flexions with the movement range from 100 degrees to 60 degrees in concentric and from 100 degrees to 140 degrees elbow angle in eccentric actions. The movements were started either from zero preactivation or with isometric preactivation of the force levels of 20, 40, 60 and 80% MVC. The subjects were then instructed to maintain the corresponding relative force levels during the dynamic actions. Intramuscular and surface EMG was recorded from biceps brachii muscle. Altogether 28 motoneuron pools were analyzed using the intramuscular spike-amplitude frequency (ISAF) analysis technique of Moritani et al. The mean spike amplitude was lower and the mean spike frequency higher in the isometric preactivation phase than in the consequent concentric and eccentric actions. When the movements started with isometric preactivation the mean spike amplitude increased significantly (P<0.001) up to 80% in isometric and concentric actions but in eccentric actions the increase continued only up to 60% (P<0.01). The mean spike frequency in isometric preactivation and in concentric action with preactivation was lower only at the 20% force level (P<0.01) as compared to the other force levels while in eccentric action with preactivation the increase between the force levels was significant (P<0.01) up to 60%. When the movement was started without preactivation the mean spike amplitude at 20% and at 40% force level was higher (P<0.01) in eccentric action than in concentric actions. It was concluded that the recruitment threshold may be lower in dynamic as compared to isometric actions. The recruitment of fast motor units may continue to higher force levels in isometric and in concentric as in eccentric actions which, on the other hand, seems to achieve the higher forces by increasing the firing rate of the active units. At the lower force levels mean spike amplitude was higher in eccentric than in concentric actions which might indicate selective activation of fast motor units. This was, however, the case only when the movements were started without isometric preactivation.

Exercise prescription based upon cardiac vagal activity for middle-aged obese women

OBJECTIVE

The purposes of this study were to examine a new method to determine exercise intensity for obese people based on the cardiac vagal activity and to determine the effect of this approach on myocardial stress.

SUBJECTS

Forty-three middle aged obese female volunteers (age 43.7+/-6.5 y; height 1.56+/-0.05 m; body mass 66.5+/-9.3 kg; body mass index 27.3+/-2.8 kg m(2); percentage body fat 40.7+/-5.9%).

MEASUREMENT

In the first experiment, 43 subjects performed a ramp exercise test on a bicycle ergometer with measurement of ECG and gas exchange parameters. In the second experiment, 11 subjects performed 45 min of constant walking exercise on a treadmill at a level corresponding to exercise intensity determined by vagal activity obtained from a ramp bicycle test. Blood pressure, endothelin 1 (ET-1), catecholamine, atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP) were measured before and after exercise.

RESULTS

The heart rate variability power decreased with increasing work rate, and changed little after reaching individual-specific work rate. We presumed that vagal activity disappeared at this point and that the heart rate at this exercise intensity was determined as the vagal activity threshold (T(VA)). The results showed a significant positive correlation (r=0.742, P<0.0001) between T(VA) and ventilatory threshold (VT) heart rates, although the mean heart rate of T(VA) (114.3+/-8.5 beats/min) was significantly lower (P<0.001) than that at VT (119.0+/-11.7), suggesting the cardiac vagal withdrawal occurred prior to the onset of lactate acidosis (lactic acid accumulation). Furthermore, exercise intervention experiment at T(VA) indicated that ET-1, catecholamine and BNP levels were not significantly different before and after exercise. However, ANP levels increased significantly after exercise (pre-exercise 18.6+/-5.38 vs post-exercise 44.0+/-24.87 pg/ml, P<0.001), which in turn brought about a significant post-exercise reduction in the blood pressure (SBP 117.6+/-13.7 vs 110.5+/-7.4 mmHg, P<0.05; DBP 78.6+/-6.7 vs 73.5+/-6.6 mmHg, P<0.01).

CONCLUSION

Our data suggest that it is possible to determine the exercise intensity (T(VA)) on the basis of cardiac vagal response. These results also suggest that exercise at T(VA) level is a safe exercise intensity in the light of cardiac stress, and that T(VA) may be recommended for obese people who might possess lower cardiac sympatho-vagal activity.

Effects of chicken essence tablets on resting metabolic rate

Resting energy expenditure (REE) values after consuming chicken essence tablets were significantly higher than those observed after consuming skim milk protein tablets (control trial). The increased thermogenic effects continued at least for a period of one hour and gradually decreased towards the baseline. The REE values during control treatment did not show such an augmented response.

Diffusion-weighted echo-planar MR imaging of CNS involvement in systemic lupus erythematosus

RATIONALE AND OBJECTIVES

The purpose of this study was to determine the range of findings at diffusion-weighted magnetic resonance (MR) imaging in patients with systemic lupus erythematosus (SLE) and central nervous system involvement.

MATERIALS AND METHODS

Diffusion-weighted MR images were reviewed in 20 patients with SLE and correlated with clinical symptoms and findings at computed tomography, conventional MR imaging, MR angiography, or conventional angiography.

RESULTS

Diffusion-weighted MR imaging showed acute or subacute lesions in nine of 20 patients (45%). In the other 11, it showed no abnormal findings or chronic lesions. In four of the nine patients with lesions, diffusion-weighted imaging primarily showed hyperintense lesions with decreased apparent diffusion coefficient (ADC), which indicates acute or subacute infarcts. In four other patients, it primarily showed iso- or slightly hyperintense lesions with increased ADC, suggesting vasogenic edema. In two of these four patients, the findings were consistent with hypertensive encephalopathy. In the other two, small hyperintense foci on diffusion-weighted images with decreased ADC were seen within the vasogenic edema. These foci presumably represent microinfarcts associated with SLE vasculopathy. In the ninth patient, diffusion-weighted imaging showed a small linear hyperintense lesion with normal ADC in the left parietooccipital region.

CONCLUSION

Diffusion-weighted imaging shows primarily two patterns of acute or subacute parenchymal lesions in patients with SLE: acute or subacute infarction and vasogenic edema with or without microinfarcts.

Exercise training and autonomic nervous system activity in obese individuals

PURPOSE

This study was designed to investigate the effects of 12 wk of exercise training on autonomic nervous system (ANS) in 18 obese middle-aged men (N = 9) and women (N = 9) (age: 41.6 +/- 1.2 yr; BMI: 27.3 +/- 0.4 kg x m(-2); %fat: 29.6 +/- 1.3%, mean +/- SE).

METHODS

Each subject participated in an aerobic exercise training at anaerobic threshold (AT), consisting of 30 min/session, 3 times/wk, for 12 consecutive weeks. The ANS activities were assessed by means of power spectral analysis of heart rate variability (HRV) at resting condition before, at 5 wk, and after the exercise program.

RESULTS

The exercise training resulted in a significant decrease in body mass, BMI, and % fat (P < 0.01) but not in lean body mass (P > 0.05) together with a significant increase in the AT VO2 (P < 0.01). Our power spectral data indicated that there were significant increases in the low-frequency component associated with the sympathovagal activity (0.03--0.15 Hz, 348.5 +/- 66.8 vs 694.7 +/- 91.5 ms(2), P < 0.01), the high-frequency vagal component (0.15--0.4 Hz, 146.3 +/- 30.4 vs 347.7 +/- 96.5 ms(2), P < 0.05), and the overall autonomic activity as evaluated by total power (0.03--0.4 Hz, 494.8 +/- 88.5 vs 1042.4 +/- 180.9 ms(2), P < 0.01) of HRV after the training.

CONCLUSIONS

Twelve weeks of exercise training has significantly improved both the sympathetic and parasympathetic nervous activities of the obese individuals with markedly reduced ANS activity, suggesting a possible reversal effect of human ANS functions. These favorable changes may also have an influence on the thermoregulatory control over the obesity.

Synergistic effect of polymorphisms of uncoupling protein 1 and beta3-adrenergic receptor genes on autonomic nervous system activity

OBJECTIVE

To investigate the association of the promoter region -3826 A to G polymorphism of the uncoupling protein 1 (UCP1) gene with autonomic nervous system (ANS) activity and the interaction of the polymorphism with the Trp64Arg polymorphism of the beta3 adrenergic receptor (beta3AR).

SUBJECTS

Three-hundred and forty-nine young (mean age 20.4+/-2.1 y old), healthy Japanese males.

MEASUREMENTS

DNA was extracted from whole blood and genotyped by polymerase chain reaction restriction fragment length polymorphism. Plasma glucose, plasma insulin and body mass index (BMI) were measured. Frequency of family history of diabetes or obesity was determined by interview. Subjects randomly chosen from each genotype were examined for ANS activity during supine rest and standing by electrocardiogram power spectral analysis of heart rate variability.

RESULTS

UCP1 or beta3AR polymorphism was not associated with BMI, plasma glucose, plasma insulin and frequency of family history of diabetes or obesity. The inhibitory effect of UCP1 polymorphism on ANS activity was observed only with occurrence of the variant of beta3AR. The very low frequency component associated with thermoregulation in the sympathetic nervous system of homozygotes of UCP1 (GG) at supine rest was significantly lower than normal (AA, 203.2+/-50.3 vs 462.2+/-83.6 ms(2); mean+/-s.e., P=0.021). A higher response to postural change to standing was also observed in both sympathetic and parasympathetic nervous activities of AA than of GG.

CONCLUSION

While UCP1 polymorphism alone does not affect ANS activity, it has a synergistic effect with beta3AR polymorphism in decreasing sympathetic nervous system activity.

Assessment of lower-back muscle fatigue using electromyography, mechanomyography, and near-infrared spectroscopy

We have investigated the etiology of lower-back muscle fatigue using simultaneous recordings of electromyography (EMG), mechanomyography (MMG), and near-infrared spectroscopy (NIRS) in an attempt to shed some light on the electrophysiological, mechanical, and metabolic characteristics, respectively. Eight male subjects performed isometric back extensions at an angle of 15 degrees with reference to the horizontal plane, for a period of 60 s. Surface EMG, MMG and NIRS signals were recorded simultaneously from the center of the erector spinae at the level of L3. NIRS was measured to determine the level of muscle blood volume (BV) and oxygenation (Oxy-Hb). The root mean square amplitude value (RMS) of the EMG signal was significantly increased at the initial phase of contraction and then fell significantly, while mean power frequency (MPF) of the EMG signal decreased significantly and progressively as a function of time. There were also significant initial increases in RMS-MMG that were followed by progressive decreases at the end of fatiguing contractions. MPF-MMG remained unchanged. Muscle BV and Oxy-Hb decreased dramatically at the onset of the contraction and then remained almost constant throughout the rest of the contraction. These results, obtained by simultaneous recordings of EMG, MMG, and NIRS, demonstrate that the restriction of blood flow due to high intramuscular mechanical pressure is one of the most important factors in muscle fatigue in the lower-back muscles. In addition, the simultaneous recording system described here can be used to obtain more reliable information regarding the mechanism(s) of lower-back muscle fatigue.

Fast MRI in obstetric diagnoses

This article describes the fast MRI of fetal abnormalities and placental anomalies in evaluation of the usefulness of fast MRI in obstetric diagnoses. Fast MRI provides excellent resolution for imaging fetal and maternal anatomies without the need for sedation. Fast MRI is therefore useful to clarify diagnoses suggested by equivocal ultrasonographic findings and to obtain additional information for prenatal counseling and management.

Capsaicin increases modulation of sympathetic nerve activity in rats: measurement using power spectral analysis of heart rate fluctuations

We assessed the sympatho-vagal activities of the heart after administration of capsaicin by measuring the power spectral analysis in rats. There were major two frequency components of heart rate variability, which we defined as high (1.0 Hz <, HF) and low (LF, < 1.0 Hz) frequency components. Vagal blockade by atropine abolished the high frequency component, and lowered the amplitude of the low frequency component. On the other hand, under conditions of sympathetic blockade by propranolol, the low frequency component was reduced. Combined vagal and sympathetic blockade abolished all heart rate fluctuations. We analyzed the low and high frequency components by integrating the spectrum for the respective band width. The rats administered capsaicin had a higher heart rate and sympathetic nervous system index (LF/HF) than the control group of rats. These results suggest that power spectral analysis is an effective and noninvasive method for detecting subtle changes in autonomic activity in response to the intake of foods or drugs.

Comparison of thermogenic sympathetic response to food intake between obese and non-obese young women

OBJECTIVE

Sympathetic nervous system abnormality in humans is still a matter of debate. The present study was designed to examine diet-induced autonomic nervous system activity and metabolic change in obese and non-obese young women.

RESEARCH METHODS AND PROCEDURES

Sixteen age- and height-matched obese and non-obese young women participated in this study. Sympathovagal activities were assessed by means of our newly developed spectral analysis procedure of heart-rate variability during the resting condition and after mixed-food ingestion (480 kcal). Energy expenditure was also measured under these two conditions.

RESULTS

There was no significant difference in any of the parameters of the heart-rate variability between the obese group and control group during the resting condition. In the control group, both absolute values (221.5 +/- 54.5 vs. 363.8 +/- 43.7 ms2, p < 0.05) and relative values (0.23 +/- 0.03 to 0.36 +/- 0.02, p < 0.05) of a very-low-frequency component and global sympathetic nervous system index (1.46 +/- 0.19 vs. 3.26 +/- 0.61, p < 0.05) were significantly increased after mixed-food ingestion compared with the values obtained after resting condition. However, no such sympathetic response was found in the obese group. Energy expenditure increased in the two groups after the meal, but the magnitude of the increase above the preprandial resting condition was significantly greater in the control group than in the obese group (11.2 +/- 2.3 vs. 6.7 +/- 0.8%, p < 0.05).

DISCUSSION

Our data suggest that despite identical sympathovagal activities at the resting condition, obese young women may possess a reduced sympathetic response to physiological perturbation such as mixed food intake, which might be related to lowered capacity of thermogenesis and the state of obesity.

Spectrum of Epstein-Barr virus infection in Japanese children: a pictorial essay

Epstein-Barr virus (EBV) infection has been associated with infectious mononucleosis, EBV-associated hemophagocytic syndrome (EBV-AHS), chronic active EBV infection (CAEBV), lymphomas, inflammatory pseudotumor, lymphomatoid granulomatosis, and nasopharyngeal carcinoma. EBV-AHS and CAEBV are more lethal than infectious mononucleosis with imaging findings of gallbladder wall thickening, pleural effusion, cardiomegaly, and hepatomegaly. EBV infection is also associated with benign and malignant tumors.

Effects of capsaicin-containing yellow curry sauce on sympathetic nervous system activity and diet-induced thermogenesis in lean and obese young women

The present study was designed to investigate the effect of capsaicin, a pungent component of red pepper, on the sympathetic nervous system (SNS) activity and energy metabolism in 16 age- and height-matched lean and obese young women. The sympatho-vagal activities were assessed by means of spectral analysis of heart rate variability (HRV) during the resting condition and after the meal (2,016 kJ) with capsaicin (3 mg). Energy expenditure was also measured under the two conditions. There was no significant difference in any of the parameters of the HRV between the obese and control groups at rest. After the capsaicin diet, however, the very low frequency component (0.007-0.035 Hz) associated with thermogenesis (315.8+/-78.0 vs. 814.8+/-211.7 ms2 x Hz(-1), p<0.05) as well as its responsiveness (delta changes: 14.6+/-104.4 vs. 369.2+/-121.7 ms2 x Hz(-1), p<0.05) were significantly lower in the obese than the control group. Energy expenditure was significantly increased in the control group after the meal (5,574.7+/-221.2 to 6,114.7+/-239.0 kJ day(-1); p<0.01), but no such significant thermogenic response was detected in the obese group despite nearly identical lean body mass of the control group. Our data indicate that regardless of the resting level of sympatho-vagal activities, the reduced sympathetic responsiveness to physiological perturbation such as a capsaicin diet, which may cause impaired diet-induced thermogenesis and further weight gain, could be an important etiological factor leading to obesity in young women.

Diffusion-weighted echo-planar MR imaging: clinical applications and pitfalls -- a pictorial essay

Diffusion-weighted imaging (DWI) provides unique information about various pathological changes of the brain. DWI is sensitive for the detection of hyperacute infarcts, and useful in distinguishing acute or subacute infarcts from chronic infarcts. DWI is useful in differentiating cytotoxic edema from vasogenic or interstitial edema, which may help to determine prognosis. DWI is useful in differentiating cystic or necrotic tumors from abscesses or epidermoids. DWI can discriminate nonenhanced tumor infiltration from vasogenic edema, and differentiate dysmyelination from demyelination.

MR evaluation of talonavicular angle in congenital talipes equinovarus

The talonavicular relationship in 14 patients with talipes equinovarus was quantified using gradient echo sequences. The angle formed between the short axis of the navicular and the long axis of the talus was measured. There is a significant difference in the talonavicular angle between patients who had posteromedial release (PMR) and those who had posterior release (PR) or casting only (P=.0004). This method provides an objective assessment of residual deformity following surgical and conservative management of talipes equinovarus.

Arterial pulse wave velocity and risk factors for peripheral vascular disease

Non-invasive measurement of arterial pulse wave velocity (PWV) is used to diagnose peripheral vascular disease. We examined the relationship between PWV and risk factors related to peripheral vascular disease [body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), atherogenic index (AI) and blood glucose (GLU)] in 45 healthy male volunteers, aged 25-85 years. The correlation coefficient of PWV with age was r = 0.46, and the correlation coefficients of PWV with DBP, AI and GLU were r = 0.71, 0.56, and 0.22, respectively (P < 0.05). Multiple linear regression analysis revealed that 67% of the variance in PWV could be accounted for by these three variables. The relative contributions of DBP, AI and GLU to PWV were 66%, 26% and 8%, respectively. To test the applicability of PWV for clinical use, a multiple regression equation of PWV derived from these three variables was then applied to male patients with hypertension (n = 53), hyperlipidaemia (n = 35) or hyperglycaemia (n = 39). The results suggest that the multiple regression equation of PWV is an indicator that discriminates between these patient categories and healthy men.

Successful transcutaneous arterial embolization of a giant hemangioma associated with high-output cardiac failure and Kasabach-Merritt syndrome in a neonate: a case report

We describe the case of a patient with a neonatal giant cutaneous hemangioma with high-output cardiac failure and Kasabach-Merritt syndrome and successfully treated with transcutaneous arterial embolization aimed at controlling severe congestive heart failure and consumption coagulopathy. A patient was admitted to the neonatal care unit on the first day of age because of a large hemangioma on his right lateral chest wall and respiratory distress, associated with cardiac failure resulting from arteriovenous shunting. On the second day of age the platelet count decreased to 5.7 x 10(4)/microliter and fibrinogen level was 85 mg/dl. The values of prothrombin time and activated partial thromboplastin time were prolonged. Intravenous predonisone therapy was started immediately, but bleeding tendency was getting worse and the evidence of congestive heart failure persisted. On the third day the patient then underwent embolization of feeding arteries with microcoils. The cardiac failure and thrombocytopenic coagulopathy had improved significantly without complications. We conclude that transcutaneous arterial embolization is an effective and safe treatment in this neonate and should be considered for the treatment of control high-output cardiac failure and coagulopathy in infants with hemangioma and Kasabach-Merritt syndrome.

Autonomic responsiveness to acute cold exposure in obese and non-obese young women

OBJECTIVE

Conflicting results have emerged over the nature of autonomic nervous system abnormalities in human obesity. This present study was designed to investigate the sympatho-vagal activities and their responsiveness to acute cold exposure in age- and height-matched obese and non-obese young women.

SUBJECTS

Twenty-four age- and height-matched obese (Weight: 68.1 +/- 2.64 kg, BMI: 26.3 +/- 0.74 kg/m2, %Fat: 39.9 +/- 1.23%) and non-obese young women (Weight: 46.9 +/- 0.77 kg, BMI: 18.5 +/- 0.18 kg/m2, %Fat: 22.9 +/- 0.8%).

MEASUREMENTS

Plasma leptin, insulin, glucose and lipid concentrations were measured at rest. The sympathetic (SNS) and parasympathetic (PNS) nervous system activities were assessed by means of power spectral analysis of heart rate variability (HRV) for 15 min under control (25 degrees C) or acute cold exposure (10 degrees C) conditions. The very low (VLO) frequency component, and SNS (low/high power), and PNS (high/total power) indexes were used to evaluate thermoregulatory sympathetic function, and cardiac sympathetic and parasympathetic nervous activities, respectively.

RESULTS

Plasma leptin concentration was significantly greater in the obese than in the control group (47.3 +/- 7.00 vs 12.1 +/- 1.22 ng.ml-1, P < 0.001). There was a highly positive correlation between plasma leptin concentration and percent of body fat (r = 0.863, P < 0.001). During the resting condition, there was no significant difference in any of the parameters of the HRV between the obese and control groups. Upon acute cold exposure, the VLO frequency component associated with thermoregulation (309 +/- 49.9 vs 578 +/- 142.2 ms2, P < 0.05) as well as its responsiveness (25-10 degrees C delta changes: 17 +/- 82.9 vs 326 +/- 138.2 ms2, P < 0.05) were significantly lower in the obese than in the control group.

CONCLUSION

Our data indicate that a reduced autonomic, especially sympathetic responsiveness associated with thermoregulation and possibly leptin resistance might be aetiological factors of obesity in young women.

The muscle sound properties of different muscle fiber types during voluntary and electrically induced contractions

Soundmyogram (SMG) and electromyogram signals were recorded simultaneously from the relatively fast medial gastrocnemius (MG) and slow soleus (SOL) during voluntary and electrically induced contractions. Using a spike-triggered averaging technique, the averaged elementary sound and corresponding MU spikes were also obtained from about 35 different MUs identified. The rms-SMG of MG increased as a function of force (P < 0.01). On the contrary, these values for SOL increased up to 60% MVC (P < 0.01), but decreased at 80% MVC. The relationship between the peak to peak amplitude of SMG and MU spike indicated significant positive correlations (r = 0.631 to approximately 0.657, P < 0.01). During electrical stimulation at 5 Hz, the SMG power spectral peak frequency (PF) was matched with stimulation frequency in both muscles. At higher stimulation frequencies, e.g., > 15 Hz, only in the MG was SMG-PF synchronized with stimulation frequency; the slow SOL did not show such synchronization. Our data suggest that the SMG frequency components might reflect active motor unit firing rates, and that the SMG amplitude depends upon mechanical properties of contraction, muscle fiber composition, and firing rate during voluntary and electrically induced contractions.

The association between Trp64Arg polymorphism of the beta3-adrenergic receptor and autonomic nervous system activity

The beta3-adrenergic receptor plays a significant role in the control of lipolysis and thermogenesis in brown adipose tissue through autonomic nervous system (ANS) activity. As the Trp64Arg polymorphism of the beta3-adrenergic receptor gene might affect ANS activity, we investigated the association of the polymorphism with ANS activity. The prevalence of the polymorphism was determined in 204 subjects. Ten normal homozygous, 10 heterozygous, and 1 variant homozygous subjects were examined for ANS activity during supine rest and standing by electrocardiogram R-R interval power spectral analysis. Subjects with the variant did not differ from subjects without the variant in body mass index, plasma glucose, plasma insulin, or family history of diabetes or obesity. The total power of heterozygotes at supine rest was lower than that of normal subjects (1124.6 +/- 191.6 vs. 3029.8 +/- 758.8 ms2; mean +/- SE). With a postural change to standing, the parasympathetic and sympathetic nervous system activity indexes of heterozygotes showed a higher response than those of normal subjects (parasympathetic nervous system index, 0.10 +/- 0.02 vs. 0.17 +/- 0.02; sympathetic nervous system index, 10.55 +/- 1.47 vs. 6.26 +/- 1.09), and the difference in total power disappeared. These findings show that subjects with the variant, even the heterozygotes, had lower resting ANS activity than normal subjects.

Aging alteration of cardiac vagosympathetic balance assessed through the tone-entropy analysis

BACKGROUND

Age-associated alterations of cardiac autonomic functions have been investigated intensively through heart rate variability analyses. However, changes with age in cardiac vagosympathetic balance remain to be elucidated.

METHODS

We studied 142 male subjects (30-69 yr) at a health care center in Kyoto, Japan. Electrocardiographic data were collected from subjects in a recumbent position for 10 min in the morning. Analysis was done by classifying the subjects into four age groups. In a pharmacological experiment carried out in December 1996, tone was verified to reflect the cardiac vagosympathetic balance, and entropy the total autonomic neural efferent activity. We assessed the heart rate variability through the tone-entropy (T-E) analysis that was described previously. In essence, two indexes, tone and entropy, were defined on a distribution of successive variations of heart period.

RESULTS

No significant differences were detected in clinical conditions among the four age groups. Tone increased and entropy decreased significantly with age. The aging process was expressed as a curvilinear path in T-E space. Compared to the pharmacological experiment, it was observed that aging degenerated the heart function from an ordinary to a denervated one. The same aging path was superimposed in the opposite direction on the heart recovery path after dynamic exercise in which cardiac vagosympathetic balance tended toward vagus division, corresponding with restoration of total autonomic activity.

CONCLUSIONS

An age-related reduction in cardiac autonomic function was consistent with previous reports. The vagosympathetic balance was altered with this reduction: vagal predominance was impaired significantly in proportion to the withdrawal of total cardiac autonomic activity.