c-Fos induction in the brainstem following electrical stimulation of the trigeminal ganglion of chronically mandibular nerve-transected rats.

Neuronal excitability in the trigeminal sensory nuclei (TSN) changes after nerve transection. We examined the effects of chronic transection of the trigeminal nerve on the c-Fos-immunoreactivity in the TSN induced 2 h after 10 min of electrical stimulation of the trigeminal ganglion (TG) at C-fiber activating condition (1.0 mA, 5 ms, 5 Hz) in urethane-anesthetized rats. In the non-transected control rats, stimulation of the TG induced c-Fos-immunoreactive cells (c-Fos-IR cells) mostly in superficial layers (VcI/II) of the nucleus caudalis (Vc) in its full extent along the dorsomedial-ventrolateral axis, but modestly in the rostral TSN above the obex, the principal, oral, and interpolar nuclei. Three days, 1, 2, or 3 weeks after transection of the inferior alveolar (IAN), infraorbital, or masseteric nerves, the stimulation of the TG induced c-Fos-IR cells in the central terminal fields of the transected nerve in the rostral TSN and magnocellular zone of the Vc. However, the number of c-Fos-IR cells in the VcI/II decreased inside the central terminal fields of the transected nerve and increased outside the fields. These results indicate that transection of the trigeminal nerve increases the excitability of TSN neurons that receive inputs from injured mechanoreceptors and uninjured nociceptors, but decreases it from injured nociceptors. The altered c-Fos responses may imply mechanisms of neuropathic pain seen after nerve injury.

Prediction of Nursing Home Admission Using the FRAIL-NH Scale Among Older Adults in Post-Acute Care Settings.

OBJECTIVES: The FRAIL-NH scale was developed to identify frailty status in nursing home residents. The purpose of this study was to examine the utility of the FRAIL-NH scale for predicting nursing home admission among patients in post-acute care settings. Design/ Setting/ Participants: This single-center, prospective, observational cohort study included participants aged 65 years or older who were admitted to a community-based integrated care ward (CICW) between July 2015 and November 2020. MEASUREMENTS: Using the CICW database, we retrospectively classified participants as robust, prefrail, or frail based on the FRAIL-NH scale the score by identifying variables from our database that were most representative of each component. The following data were collected: examination findings, CICW admission and discharge information, length of CICW stay, and nursing home admission. The participants were divided into two groups based on whether or not they were admitted to a nursing home after CICW discharge. The hazard ratios (HRs) and 95% confidence intervals (CIs) for nursing home admission were calculated according to the FRAIL-NH categories using the Cox proportional hazards models with reference to the robust group. In the multivariate adjusted model, we adjusted for age, sex, nutritional status, cognitive function, living status, and economic status. RESULTS: Data of 550 older adults were analyzed, of which 118 were admitted and 432 were not admitted to a nursing home. The frail group had a higher risk of nursing home admission (HR, 2.22; 95% CI 1.32-3.76) than the robust group. CONCLUSIONS: This study showed that the FRAIL-NH scale was beneficial for predicting nursing home admission among older adults in the post-acute care setting. Thus, assessment using the FRAIL-NH scale may help to consider preparation and support for life after discharge.

Risk factors for infantile atopic dermatitis and recurrent wheezing.

BACKGROUND: The pathogenic mechanisms of atopic dermatitis (AD) and recurrent wheezing (RW) during infancy are not fully understood. OBJECTIVE: We evaluated immunological markers associated with AD and RW during infancy. METHODS: We followed a cohort (n = 314) from birth to 14 months of age. Some of the participants underwent a physical examination and blood test at 6 and 14 months of age. Univariate and multivariate logistic regression analysis and receiver operating characteristic curve analysis were performed to find which immunological markers could be risk factors for AD and RW. RESULTS: Of 16 immunological markers found in cord blood, only immunoglobulin (Ig) E was associated with AD at 6 months of age (adjusted OR [aOR], 1.607). None of the markers was associated with AD or RW at 14 months of age. Of 23 immunological markers at 6 months of age, total IgE (aOR, 1.018) and sensitization to egg white (aOR, 23.246) were associated with AD at 14 months of age. Phytohemagglutinin (PHA)-induced production of interleukin (IL) 4 from peripheral blood mononuclear cells (PBMCs) (aOR, 1.043) was associated with RW at 14 months of age. CONCLUSION: Cord blood IgE was a risk factor for AD at 6 months of age. Total IgE and sensitization to egg white at 6 months of age were risk factors for AD at 14 months of age. PHA-induced IL-4 production in PBMCs at 6 months of age was a risk factor for RW at 14 months of age.

Effect of long-term physical exercise of peripheral nerve: comparison of nerve conduction study and ultrasonography.

AIM: The aim of this study was to assess the effects of long-term physical exercise on peripheral nerve using both nerve conduction study (NCS) and ultrasonography (US). METHODS: The authors measured nerve conduction study and ultrasonography in 15 male (mean, 20±1.5 years) handball players and 13 male (mean, 21.3±1.9 years) control subjects. Cross-sectional area of the median nerve was evaluated using ultrasonography at the carpal tunnel and 6 cm proximal to the wrist, and the ulnar nerve at 6 cm proximal to the wrist crease, 2 cm proximal to the medial epicondyle, the epicondyle, and 2 cm distal to epicondyle. RESULTS: US shows significantly increased cross-sectional area of both median and ulnar nerve in the players compared with that in the controls, and the latency times in both nerves were significantly delayed in the players compared with that in the controls. Cross-sectional area of the median nerve showed a significant correlation with latency (r=0.330, P<0.01). CONCLUSION: This study suggests that the players have a tendency toward having both median and ulnar motor nerve damage in the wrist or elbow region although they are asymptomatic.

Physical Frailty and Hemoglobin-to-Red Cell Distribution Width Ratio in Japanese Older Outpatients.

The Frailty screening should be widely performed; however, simple and inexpensive biomarkers are missing. Biomarkers that can be routinely assessed in many patients are desirable. Recently, the hemoglobin-to-red cell distribution width ratio (Hb/RDW, HRR) has been suggested as a new prognostic marker and has been reported to be associated with inflammation, one of the factors contributing to frailty. Therefore, we aimed to address the role of HRR in frailty among 557 older outpatients (aged 65-96 years). Frailty was assessed using the Japanese version of the Cardiovascular Health Study criteria, and HRR was calculated from clinical records. Participants were classified into five groups based on a sex-stratified quintile of HRR (Q1-Q5). Of the participants, 20.3% were frail. Using multiple logistic regression models with the Q5 group as a reference, after adjusting for sex, age, body mass index, polypharmacy, pre-orthopedic surgery, and the use of iron medications, the multivariable-adjusted odds ratios (95% confidence intervals) of the Q4 to Q1 groups were 0.92 (0.58-1.47), 1.04 (0.67-1.61), 1.29 (0.84-1.96), and 1.85 (1.22-2.82), respectively, indicating that a lower HRR was significantly associated with frailty. The robustness of these results was also shown in the multiple imputation analysis. The results suggest that HRR measurement may be one of the indicators to identify frail older adults in routine practice.

Long-term changes in airway-wall thickness on computed tomography in asthmatic patients.

BACKGROUND: Effects of long-term treatment with inhaled corticosteroids (ICSs) on airway-wall thickness in patients with asthma remain unknown. OBJECTIVES: To determine whether airway-wall thickness consistently decreases after long-term ICS treatment, and to analyze factors contributing to long-term airway-wall changes in asthmatics. METHODS: A retrospective analysis of long-term changes in airway-wall thickness using computed tomography was performed in 14 patients with asthma. Wall area corrected by body surface area (WA/BSA) was examined at baseline, 12 weeks after the commencement of ICSs (second measurement), and at least 2 years (mean +/- SEM. 4.2 +/- 0.5) after the second measurement (third measurement). Mean +/- SEM changes in WA/BSA from the second to the third measurements were analyzed. RESULTS: The mean change in WA/BSA was not significant between the second and the third measurements (-0.27 +/- 0.59 mm2/m2/y). Overall, the changes were significantly associated with disease duration but not with other clinical indices. When the 14 patients were divided into 2 groups using a cutoff value of 0.32 mm2/m2/y for the mean change in WA/BSA, for the 5 patients whose WA/BSA exceeded this cutoff, daily ICS doses were not reduced and both forced expiratory volume in the first second (FEV1) and forced vital capacity decreased significantly. For the remaining 9 patients, daily ICS doses were reduced and long-term FEV1 values did not change. CONCLUSIONS: Despite long-term treatment with ICSs, airway-wall thickness did not consistently decrease. One possible mechanism underlying poor response to long-term treatment may be long-standing asthma.

Virus activation and immune function during intense training in rugby football players.

Epidemiological studies suggest that highly trained athletes are more susceptible to upper respiratory tract infections (URTI) compared with the general population. Upper respiratory symptoms (URS) often appear as either primary invasion of pathogenic organisms and/or reactivation of latent viruses such as Epstein-Barr virus (EBV). The purpose of this study was to examine the relationship between EBV reactivation and the appearance of URS during intensive training in collegiate rugby football players. We evaluated EBV-DNA expression in saliva and examined the relationship between onset of URS and daily changes in EBV-DNA as well as secretory immunoglobulin A (SIgA) levels among 32 male collegiate rugby football players during a 1-month training camp. The EBV-DNA expression tended to be higher in subjects who exhibited sore throat (p=0.07) and cough (p=0.18) than that of those who had no symptoms, although their differences were not significant. The SIgA level was significantly lower 1 day before the EBV-DNA expression (p<0.05). The number of URS increased along with the EBV-DNA expression and decrease of SIgA levels. These results suggest that the appearance of URS is associated with reactivation of EBV and reduction of SIgA during training.

Luminal hydrogen sulfide plays a pronociceptive role in mouse colon.

OBJECTIVE: Given recent evidence that hydrogen sulfide (H(2)S), a gasotransmitter, promotes somatic pain through redox modulation of T-type Ca(2+) channels, the roles of colonic luminal H(2)S in visceral nociceptive processing in mice were examined. METHODS: After intracolonic administration of NaHS, an H(2)S donor, visceral pain-like behaviour and referred abdominal allodynia/hyperalgesia were evaluated. Phosphorylation of extracellular signal-regulated protein kinase (ERK) in the spinal dorsal horn was determined immunohistochemically. The whole-cell recording technique was used to evaluate T-type Ca(2+) currents (T-currents) in cultured dorsal root ganglion (DRG) neurons. RESULTS: Like capsaicin, NaHS, administered intracolonically at 0.5-5 nmol per mouse, triggered visceral nociceptive behaviour accompanied by referred allodynia/hyperalgesia in mice. Phosphorylation of ERK in the spinal dorsal horn was detected following intracolonic NaHS or capsaicin. The behavioural effects of intracolonic NaHS were abolished by a T-type channel blocker or an oxidant, but not inhibitors of L-type Ca(2+) channels or ATP-sensitive K(+) (K(ATP)) channels. Intraperitoneal NaHS at 60 micromol/kg facilitated intracolonic capsaicin-evoked visceral nociception, an effect abolished by the T-type channel blocker, although it alone produced no behavioural effect. In DRG neurons, T-currents were enhanced by NaHS. CONCLUSIONS: These findings suggest that colonic luminal H(2)S/NaHS plays pronociceptive roles, and imply that the underlying mechanisms might involve sensitisation/activation of T-type channels probably in the primary afferents, aside from the issue of the selectivity of mibefradil.

Association of Muscle Strength and Gait Speed with Cross-Sectional Muscle Area Determined by Mid-Thigh Computed Tomography - A Comparison with Skeletal Muscle Mass Measured by Dual-Energy X-Ray Absorptiometry.

BACKGROUND: Muscle mass is often mentioned not to reflect muscle strength. For muscle mass assessment skeletal muscle index (SMI) is often used. We have reported that dual-energy X-ray absorptiometry (DXA)-derived SMI does not change with age in women, whereas the cross-sectional muscle area (CSMA) derived from computed tomography (CT) does. OBJECTIVES: The present study aimed to compare CT and DXA for the assessment of muscle tissue. DESIGN AND SETTING: Cross-sectional study in the local residents. PARTICIPANTS: A total of 1818 subjects (age 40-89 years) randomly selected from community dwellers underwent CT examination of the right mid-thigh to measure the cross-sectional muscle area (CSMA). Skeletal muscle mass (SMM) was measured by DXA. The subjects performed physical function tests such as grip strength, knee extension strength, leg extension strength, and gait speed. The correlation between CT-derived CSMA and DXA-derived SMM along with their association with physical function was examined. RESULTS: After controlling for related factors, the partial correlation coefficient of muscle cross-sectional area (CSA) with physical function was larger than that of DXA-derived SMM for gait speed in men (p=0.002) and knee extension strength in women (p=0.03). The partial correlation coefficient of quadriceps (Qc) CSA with physical function was larger than that of DXA-derived SMM for leg extension power in both sexes (p=0.01), gait speed in men (p<0.001), and knee extension strength in women (p<0.001). CONCLUSION: Mid-thigh CT-derived CSMA, especially Qc CSA, showed significant associations with grip strength, knee extension strength, and leg extension power, which were equal to or stronger than those of DXA-derived SMM in community-dwelling middle-aged and older Japanese people. The mid-thigh CSMA may be a predictor of mobility disability, and is considered to be useful in the diagnosis of sarcopenia.

Improving the Quality of Synthetic FLAIR Images with Deep Learning Using a Conditional Generative Adversarial Network for Pixel-by-Pixel Image Translation.

BACKGROUND AND PURPOSE: Synthetic FLAIR images are of lower quality than conventional FLAIR images. Here, we aimed to improve the synthetic FLAIR image quality using deep learning with pixel-by-pixel translation through conditional generative adversarial network training. MATERIALS AND METHODS: Forty patients with MS were prospectively included and scanned (3T) to acquire synthetic MR imaging and conventional FLAIR images. Synthetic FLAIR images were created with the SyMRI software. Acquired data were divided into 30 training and 10 test datasets. A conditional generative adversarial network was trained to generate improved FLAIR images from raw synthetic MR imaging data using conventional FLAIR images as targets. The peak signal-to-noise ratio, normalized root mean square error, and the Dice index of MS lesion maps were calculated for synthetic and deep learning FLAIR images against conventional FLAIR images, respectively. Lesion conspicuity and the existence of artifacts were visually assessed. RESULTS: The peak signal-to-noise ratio and normalized root mean square error were significantly higher and lower, respectively, in generated-versus-synthetic FLAIR images in aggregate intracranial tissues and all tissue segments (all P < .001). The Dice index of lesion maps and visual lesion conspicuity were comparable between generated and synthetic FLAIR images (P = 1 and .59, respectively). Generated FLAIR images showed fewer granular artifacts (P = .003) and swelling artifacts (in all cases) than synthetic FLAIR images. CONCLUSIONS: Using deep learning, we improved the synthetic FLAIR image quality by generating FLAIR images that have contrast closer to that of conventional FLAIR images and fewer granular and swelling artifacts, while preserving the lesion contrast.

Laparoscopic gastrectomy for gastric cancer: experience with more than 600 cases.

BACKGROUND: Among the less invasive operations noted in recent years, laparoscopic gastrectomy for gastric cancer has become popular because of advances in surgical techniques. The authors performed laparoscopic gastrectomy with regional lymph node dissection for 612 cases of gastric malignancies between March 1998 and August 2006. The technique and results of laparoscopic gastrectomy for gastric cancer are presented. METHODS: Of the 612 gastric malignancy cases, distal gastrectomy was performed in 485 cases, proximal gastrectomy in 42 cases, and total gastrectomy in 85 cases. In all the cases, D1 or D2 lymph node dissection was performed according to the general rule of the Japanese Gastric Cancer Association. RESULTS: Quicker recovery was observed in the laparoscopic gastrectomy cases than in the open cases. The postoperative complications with this technique were within a permissible range. No statistical difference was seen in the survival curve after surgery between the laparoscopic group of advanced cases preoperatively diagnosed as surgical T2N1 or lower and the open group. CONCLUSION: The laparoscopic technique is not only less invasive, but also similarly safe and curative compared with open gastrectomy.

Sputum levels of transforming growth factor-beta1 in asthma: relation to clinical and computed tomography findings.

BACKGROUND: Transforming growth factor (TGF) beta1 is considered to play central roles in the pathogenesis of airway remodeling in asthma. This notion is based primarily on the results of experimental studies; clinical evidence is limited. OBJECTIVES: To ascertain the involvement of TGF-beta1 in asthma. METHODS: We studied 27 patients with moderate-to-severe, but stable, asthma treated with inhaled corticosteroids and 8 healthy controls. Helical computed tomography scans were acquired at full inspiration. Airway wall thickness (WT) was assessed on the basis of wall area corrected for body surface area (WA/BSA) and absolute WT corrected for BSA (WT/square root of BSA) according to a validated method. Induced sputum concentrations of TGF-beta1 were measured by enzyme-linked immunosorbent assay. Pulmonary function was evaluated. RESULTS: Indices of expiratory airflow were significantly lower in the asthmatic patients than in the controls. WA/BSA, WT/square root of square root of BSA, and sputum concentrations of TGF-beta1 were significantly higher in the asthmatic patients. Sputum TGF-beta1 concentrations correlated positively with WA/BSA and WT/square root of BSA and negatively with forced expiratory volume in 1 second in both asthmatic and control subjects. CONCLUSIONS: Levels of TGF-beta1 in induced sputum are elevated in asthmatic patients despite treatment with inhaled corticosteroids and are associated with airflow obstruction and airway wall thickening. TGF-beta1 is involved in the pathogenesis of airway remodeling and resultant functional impairment and it may be a target for specific medical treatment.

Expression and localization of human oxytocin receptor mRNA and its protein in chorion and decidua during parturition.

Oxytocin (OT) is widely used to induce labor in the clinical setting. However, its physiological role in normal human parturition remains unclear. We demonstrated the enhanced expression of OT receptor (OTR) mRNA in chorio-decidual tissue, using the polymerase chain reaction after the reverse transcriptase reaction (RT-PCR) and Northern blot analysis. OTR gene expression in chorio-decidual tissue increased fivefold during the course of parturition. In situ hybridization of fetal membrane revealed the expression of OTR mRNA in maternally derived decidual cells. The OTR mRNA was also detected in fetally derived chorionic trophoblast cells. Immunohistochemistry, using a newly developed anti-OTR monoclonal antibody, demonstrated the distribution of OTR protein in fetal membrane. The distribution pattern of OTR protein and OTR mRNA was identical, indicating that the regulation of OTR expression occurs mainly at the transcriptional level. These results support the idea that the expression of decidual OTR regulates the initiation and amplification of labor. The implications of these findings with regard to the pathogenesis of preterm labor are also discussed.

Blockade of brain histamine metabolism alters methamphetamine-induced expression pattern of stereotypy in mice via histamine H1 receptors.

The administration of methamphetamine (METH, 10 mg/kg, i.p.) to male ICR mice induced stereotyped behavior consisting of nail and/or wood chip biting (86.0%), continuous sniffing (12.0%), head bobbing (1.1%), and circling (1.0%) during the observation period of 1 h. Pretreatment of the mice with metoprine (2, 10, and 20 mg/kg, i.p.), a selective inhibitor of histamine N-methyltransferase (HMT), which metabolizes histamine in the brain, significantly increased and decreased METH-induced continuous sniffing (20.5, 51.3, and 80.3%) and nail and/or wood chip biting (77.4, 45.3, and 14.2%), respectively, in a dose-dependent manner. The hypothalamic contents of histamine and its metabolite N(tau)-methylhistamine were significantly increased and decreased by metoprine (10 mg/kg, i.p.), respectively. The metoprine action on METH-induced behavior was completely abolished by pyrilamine (10 and 20 mg/kg) and ketotifen (10 mg/kg), selective, centrally acting histamine H(1) receptor antagonists, but not by fexofenadine (20 mg/kg), zolantidine (10 mg/kg) and thioperamide (10 mg/kg), a peripherally acting histamine H(1) receptor antagonist and a selective, brain-penetrating antagonist for histamine H(2) and H(3) receptors, respectively. The metoprine action was mimicked by SKF 91488 (100 microg/animal, i.c.v.), another HMT inhibitor, and the action of SKF 91488 was also blocked by pyrilamine. The frequency of the expression of METH-induced total stereotypic patterns was unchanged after metoprine pretreatment. Mice pretreated with metoprine displayed no anxiety-like behavior in the elevated plus maze test. These results suggest that brain histamine, increased by agents such as metoprine and SKF 91488, binds to histamine H(1) receptors in the brain, resulting in the modulation of dopaminergic transmission associated with stereotyped behavioral patterns induced by METH.

Atopic features of cough variant asthma and classic asthma with wheezing.

BACKGROUND: Cough variant asthma is a phenotype of asthma solely presenting with coughing. It involves airway inflammation and remodelling as does classic asthma with wheezing, and a subset of patients may progress to classic asthma. The atopic features of cough variant asthma remain unclear. OBJECTIVE: To compare atopic features between patients with cough variant asthma and those with classic asthma, and to examine the possible correlation of these features with the future development of wheezing in the former group. METHODS: Total and specific IgE levels of seven common aeroallergens [house dust mite (HDM), Gramineae/Japanese cedar/weed pollens, moulds, cat/dog dander] were examined in 74 cough variant asthma patients and in 115 classic asthma patients of varying severity. Forty of the former patients were prospectively observed for 2 years to determine whether cough variant asthma progressed to classic asthma despite inhaled corticosteroid treatment. RESULTS: Patients with classic asthma had higher total IgE (P<0.0001), larger numbers of sensitized allergens (P=0.03), and higher rates of sensitization to dog dander (24% vs. 3%, P<0.0001), HDM (46% vs. 28%, P=0.02), and moulds (17% vs. 7%, P=0.047) than did patients with cough variant asthma. Wheezing developed in six (15%) patients with cough variant asthma, who were sensitized to larger numbers of allergens (P=0.02) and had higher rates of sensitization to HDM (P=0.01) and dog dander (P=0.02) than the 34 patients in whom wheezing did not develop. Among the patients with classic asthma, total and specific IgE variables were similar in the subgroup with mild disease (n=60) and the subgroup with moderate-to-severe disease (n=55), as reported previously. CONCLUSIONS: Atopy may be related to the development of wheezing in patients with cough variant asthma. To prevent the progression of cough variant asthma to classic asthma, avoidance of relevant allergens may be essential.

Utility of a Multiparametric Quantitative MRI Model That Assesses Myelin and Edema for Evaluating Plaques, Periplaque White Matter, and Normal-Appearing White Matter in Patients with Multiple Sclerosis: A Feasibility Study.

BACKGROUND AND PURPOSE: T1 and T2 values and proton density can now be quantified on the basis of a single MR acquisition. The myelin and edema in a voxel can also be estimated from these values. The purpose of this study was to evaluate a multiparametric quantitative MR imaging model that assesses myelin and edema for characterizing plaques, periplaque white matter, and normal-appearing white matter in patients with MS. MATERIALS AND METHODS: We examined 3T quantitative MR imaging data from 21 patients with MS. The myelin partial volume, excess parenchymal water partial volume, the inverse of T1 and transverse T2 relaxation times (R1, R2), and proton density were compared among plaques, periplaque white matter, and normal-appearing white matter. RESULTS: All metrics differed significantly across the 3 groups (P < .001). Those in plaques differed most from those in normal-appearing white matter. The percentage changes of the metrics in plaques and periplaque white matter relative to normal-appearing white matter were significantly more different from zero for myelin partial volume (mean, -61.59 ± 20.28% [plaque relative to normal-appearing white matter], and mean, -10.51 ± 11.41% [periplaque white matter relative to normal-appearing white matter]), and excess parenchymal water partial volume (13.82 × 103 ± 49.47 × 103% and 51.33 × 102 ± 155.31 × 102%) than for R1 (-35.23 ± 13.93% and -6.08 ± 8.66%), R2 (-21.06 ± 11.39% and -4.79 ± 6.79%), and proton density (23.37 ± 10.30% and 3.37 ± 4.24%). CONCLUSIONS: Multiparametric quantitative MR imaging captures white matter damage in MS. Myelin partial volume and excess parenchymal water partial volume are more sensitive to the MS disease process than R1, R2, and proton density.

Synthetic MRI in the Detection of Multiple Sclerosis Plaques.

BACKGROUND AND PURPOSE: Synthetic MR imaging enables the creation of various contrast-weighted images including double inversion recovery and phase-sensitive inversion recovery from a single MR imaging quantification scan. Here, we assessed whether synthetic MR imaging is suitable for detecting MS plaques. MATERIALS AND METHODS: Quantitative and conventional MR imaging data on 12 patients with MS were retrospectively analyzed. Synthetic T2-weighted, FLAIR, double inversion recovery, and phase-sensitive inversion recovery images were produced after quantification of T1 and T2 values and proton density. Double inversion recovery images were optimized for each patient by adjusting the TI. The number of visible plaques was determined by a radiologist for a set of these 4 types of synthetic MR images and a set of conventional T1-weighted inversion recovery, T2-weighted, and FLAIR images. Conventional 3D double inversion recovery and other available images were used as the criterion standard. The total acquisition time of synthetic MR imaging was 7 minutes 12 seconds and that of conventional MR imaging was 6 minutes 29 seconds The lesion-to-WM contrast and lesion-to-WM contrast-to-noise ratio were calculated and compared between synthetic and conventional double inversion recovery images. RESULTS: The total plaques detected by synthetic and conventional MR images were 157 and 139, respectively (P = .014). The lesion-to-WM contrast and contrast-to-noise ratio on synthetic double inversion recovery images were superior to those on conventional double inversion recovery images (P = .001 and < 0.001, respectively). CONCLUSIONS: Synthetic MR imaging enabled detection of more MS plaques than conventional MR imaging in a comparable acquisition time. The contrast for MS plaques on synthetic double inversion recovery images was better than on conventional double inversion recovery images.

In vitro expansion of mammalian telomere repeats by DNA polymerase alpha-primase.

Among the polymerases, DNA polymerase alpha-primase is involved in lagging strand DNA synthesis. A previous report indicated that DNA polymerase alpha-primase initiates primer RNA synthesis with purine bases on a single-stranded G-rich telomere repeat. In this study, we found that DNA polymerase alpha-primase precisely initiated with adenosine opposite the 3'-side thymidine in the G-rich telomere repeat 5'-(TTAGGG)(n)-3' under rATP-rich conditions. Then, DNA polymerase alpha-primase synthesized the nascent DNA fragments by extending the primer. It was remarkable that DNA polymerase alpha-primase further expanded the product DNA far beyond the length of the template DNA, as ladders of multiple hexanucleotides on polyacrylamide gel electrophoresis. Using an oligomer duplex 5'-A(GGGTTA)(5)-3'/5'-(TAACCC)(5)T-3' as a template-primer, we show that both the Klenow fragment of Escherichia coli DNA polymerase I and HIV reverse transcriptase could expand telomere DNA sequences as well, giving products greater than the size of the template DNA. The maximum product lengths with these polymerases were approximately 40-90 nt longer than the template length. Our data imply that DNA polymerases have an intrinsic activity to expand the hexanucleotide repeats of the telomere sequence by a slippage mechanism and that DNA polymerase alpha uses both the repeat DNA primers and the de novo RNA primers for expansion. On the other hand, a plasmid harboring a eukaryotic telomere repeat showed remarkable genetic instability in E.coli. The telomere repeats exhibited either expansions or deletions by multiple hexanucleotide repeats during culture for a number of generations, suggesting involvement of the slippage mechanism in the instability of telomeric DNA in vivo.

Difference in stretching of sarcomeres between medial gastrocnemius and tibialis anterior by tibial lengthening: an experiment in rabbits.

PURPOSE: To compare the degree of stretching of sarcomeres--in the medial gastrocnemius versus the tibialis anterior--acutely extended by tibial lengthening. METHODS: The right lower legs of 6 New Zealand White rabbits were acutely distracted by 6.3 mm using an external fixator, whereas the left lower legs served as controls. Immediately after distraction, the ankle was dorsiflexed at 50 degrees and the knee flexed at 140 degrees, with respect to the posture of resting on the ground. Both legs were immersed in 10% buffered formalin for fixation, and the medial gastrocnemius and tibialis anterior were removed. Length of the 2 sarcomeres was measured by a laser diffraction technique using isolated muscle fibre bundles. RESULTS: The mean lengths of sarcomeres in the medial gastrocnemius and tibialis anterior were 3.0 microm and 2.3 microm in the lengthened legs, and 2.4 microm and 2.1 microm in control legs, respectively. The degree of stretching of corresponding sarcomeres was therefore 25% and 10%, this difference being significant (p<0.01). CONCLUSION: Sarcomeres of the medial gastrocnemius are more stretchable than those of the tibialis anterior following tibial lengthening.

Phosphorylated retinoblastoma protein stimulates DNA polymerase alpha.

Human retinoblastoma (Rb) protein, immunopurified from an extract of recombinant baculovirus infected cells, stimulated 10-100-fold the activity of DNA polymerase alpha from calf thymus or human HeLa cells. Purified Rb protein is composed of two electrophoretically distinguishable forms, i.e., partially phosphorylated and under-phosphorylated forms. Dephosphorylation of Rb protein by protein phosphatase 2A largely diminished its stimulatory effect. On the other hand, a hyperphosphorylated Rb protein, obtained from insect cells overexpressing Rb protein, cyclin E and cyclin-dependent kinase 2 simultaneously, stimulated DNA polymerase alpha more strongly than the singly-expressed Rb protein. These results indicate that the phosphorylation is crucial for the stimulation. Rb protein isolated from human Burkitt lymphoma Raji cells also stimulated DNA polymerase alpha. In contrast, Rb protein did not affect eukaryotic DNA primase or Klenow fragment of Escherichia coli DNA polymerase I. By immunoprecipitation using anti-DNA polymerase alpha antibody, Rb protein in nuclear extract of Raji cells was co-precipitated with DNA polymerase alpha. This result indicates that DNA polymerase alpha exists as a complex containing phosphorylated Rb protein in cells. DNA polymerase alpha specifically bound to a purified Rb protein-immobilized Sepharose column. Rb protein also bound to DNA polymerase alpha trapped to anti-DNA polymerase alpha antibody-Sepharose column, suggesting the direct association of these two proteins. These observations suggest a new function of phosphorylated Rb protein in the regulation of DNA replication.