Specific tension of elbow flexor and extensor muscles based on magnetic resonance imaging

Series cross-section images of the upper extremity were obtained for four men by magnetic resonance imaging (MRI) and anatomical cross-sectional areas (ACSA) of elbow flexor muscles [biceps brachii (BIC), brachialis (BRA), brachioradialis (BRD)] and extensor muscles [triceps brachii (TRI)] were measured. Physiological cross-sectional area (PCSA) was calculated from the muscle volume and muscle fibre length, the former from the series ACSA and the latter from the muscle length multiplied by previously reported fibre/muscle length ratios. Elbow flexion/extension torque was measured using an isokinetic dynamometer and the force at the tendons was calculated from the torque and moment arms of muscles measured by MRI. Maximal ACSA of TRI was comparable to that of total flexors, while PCSA of TRI was greater by 1.9 times. Within flexors, BRA had the greatest contribution to torque (47%), followed by BIC (34%) and BRD (19%). Specific tension related to the estimated velocity of muscle fibres were similar for elbow flexors and extensors, suggesting that the capacity of tension development is analogous between two muscle groups.     

Helicobacter pylori seropositivity and IL-1B C-31T polymorphism among Japanese Brazilians

We reported previously that anti-Helicobacter pylori antibody seropositivity (HP+) had an association with interleukin 1B (IL-1B) C-31T genotype, especially among smokers. This study examined the association for Japanese Brazilians. In this cross-sectional study, voluntary participation was announced through Japanese Brazilian communities in Sao Paulo, Curitiba, Mogi das Cruzes, and Mirandopolis; 963 Japanese Brazilians (399 males and 564 females) aged 33-69 years participated. Lifestyle data and peripheral blood were collected. An anti-HP IgG antibody test and genotyping for IL-1B C-31T and IL-1RN 86 bp VNTR were independently conducted. The genotype frequency of the IL-1B polymorphism among 947 individuals was 23.9% for C/C genotype, 45.6% for C/T genotype, and 30.5% for T/T genotype. Sex-age-adjusted odds ratio (aOR) of HP+ was 1.30 (95% confidence interval, 0.94-1.81) for C/T genotype and 1.45 (1.02-2.07) for T/T genotype relative to C/C genotype. The aOR for 127 current smokers was 2.45 (0.91-6.55) for C/T and 3.49 (1.17-10.46) for T/T, while that for 667 never smokers was 1.21 (0.82-1.78) and 1.36 (0.90-2.05), respectively. The corresponding figures were 2.42 (1.16-5.02) and 3.00 (1.33-6.78) for 226 current drinkers, and 1.21 (0.82-1.78) and 1.36 (0.90-2.05) for 667 non-drinkers. The difference in the OR was observed for milk consumption, salty pickled vegetable eating, and physical exercise practice. 4/4 Genotype of IL-1RN 86 bp VNTR was 84.8%, and had no association with the HP seropositivity. The observed association between HP+ and IL-1B -31TT indicated that the genetic trait also influences the susceptibility to HP for Japanese in Brazil.     

De novo interstitial deletion of 4q[46,XX,del(4)(q27q28.2)] with intact blood group-MN locus,confining its locus to 4q28.2–4q31.1

We report a malformed female infant withde novo interstitial deletion of 4q[46,XX,del(4)(q27q28.2)]. The MN blood type analysis of the family members showed that the patient had an intact blood group-MN locus. The locus of the gene responsible for the MN antigen activity is confined to a 4q28.2–4q31.1 segment on the basis of the result of this patient and the previous mapping data.     

Membrane potential changes in vocal cord tensor motoneurons during breathing, vocalization, coughing and swallowing in decerebrate cats

We studied the patterns of membrane potential changes in vocal cord tensor motoneurons, i.e. cricothyroid muscle motoneurons (CTMs), during fictive breathing, vocalization, coughing, and swallowing in decerebrate paralyzed cats to determine the nature of central drives to CTMs during these behaviors. CTMs were identified by antidromic activation from the superior laryngeal nerve. During breathing, CTMs always depolarized during the inspiratory phase, and sometimes depolarized during the expiratory phase as well. During vocalization, CTMs strongly depolarized. During coughing, CTMs exhibited depolarizations during both inspiratory and expiratory phases, but it was interrupted by a transient repolarization between the last part of the inspiratory phase and the first part of the abdominal burst during which chloride-dependent inhibitory postsynaptic potentials were revealed. During swallowing, most CTMs hyperpolarized, and this hyperpolarization was sometimes followed by a weak depolarization. We conclude that the main role of the cricothyroid muscle is vocalization but the functional roles in coughing and swallowing are minor, and that the CTM activity during resting breathing and vocalization are primarily controlled by excitatory inputs, while during coughing and swallowing, inhibitory inputs play roles in shaping membrane potential trajectories.     

Application of Scanning Acoustic Microscopy for Assessing Stress Distribution in Atherosclerotic Plaque

Scanning acoustic microscopy (SAM) was equipped to assess the acoustic properties of normal and atherosclerotic coronary arteries. The SAM image in the atherosclerotic lesion clearly demonstrated that the sound speed was higher than that in the normal intima, and that the variation of elasticity was found within the fibrous cap of the plaque. Young's elastic modulus of each region was calculated and the finite element analysis was applied to derive the stress distribution in these arterial walls. In a case of normal coronary artery, the stress was dominant in the intima and the distribution was rather homogeneous and in a case of atherosclerosis, high stress was concentrated to the relatively soft lesion in the fibrous cap overlying lipid pool. SAM provides information on the physical properties, which cannot be obtained by the optical microscope. The results would help in understanding the pathological features of atherosclerosis. © 2001 Biomedical Engineering Society. PAC01: 8764-t, 8763Df, 8719Xx, 8719Rr     

Loss of LMP and TAP expression in human melanoma cells

The goal of this study was to determine the frequency of LMP2, LMP7, TAP1 and/or TAP2 loss in melanoma cell lines and in surgically removed melanoma lesions. Cell extracts from control and IFN-γ treated melanoma cell lines were tested in Western blotting with antisera elicited with LMP2, LMP7, TAP1 and TAP2-specific peptides. LMP2 and LMP7 were not detected in 7 out of 9 cell lines. Expression of both LMP subunits was induced in 5 of the 7 negative cell lines by treatment with IFN-γ. TAP1 and TAP2 were not detected in 3 out of 9 cell lines and were induced in one of them by IFN-γ. Surgically removed lesions were stained in the immunoperoxidase reaction with antibodies purified from the antisera by affinity chromatography on the immunizing peptides. LMP2 and LMP7 were not detected in 20% and 6%, respectively, of 32 primary lesions and in 40% and 12%, respectively, of 25 metastatic lesions. TAP1 and TAP2 were not detected in 15% and 18%, respectively, of 32 primary lesions and in 20% and 24%, respectively, of 25 metastatic lesions. Moreover, the frequency of TAP loss is increased in primary lesions from patients with recurrence of their disease, suggesting a potential role in the course of the disease and a negative impact on the outcome of T cell-based immunotherapy.     

Accumulation of somatic hypermutation and antigen-driven selection in rapidly cycling surface Ig+ germinal center (GC) B cells which occupy GC at a high frequency during the primary antihapten response in mice

Well-developed germinal centers (GC) contain rapidly dividing surface immunoglobulin-negative (sIg^-) B cells (centroblasts), and most of their progeny are sIg⁺ B cells (centrocytes) in a resting state. It has been predicted that somatic hypermutation occurs in centroblasts, whereas antigen-driven selection takes place in centrocytes. The present analysis indicates that murine GC B cells bearing sIg with specificity for an immunizing antigen are in a rapidly cycling state and increase exponentially in number to occupy spleen GC at high frequency during the 1st week after primary immunization; however, the number of these cells is significantly reduced in the 2nd week of immunization. During that period, these proliferating sIg⁺ GC B cells accumulate somatic hypermutations with nucleotide exchanges indicative of affinity maturation. These sIg⁺ GC B cells co-express B7-2, ICAM-1, and LFA-1, and have potent antigen-presenting activity which results in T cell activation in vitro. These observations indicate that the sIg⁺ GC B cells accumulate somatic hypermutations and undergo antigen-driven selection through proliferation, probably upon activation by T cells. This sIg⁺ GC B cell population may represent cell cycling centrocytes; however, the possibility that these may represent centroblasts undergoing re-expression of sIg could not be excluded.     

Comparison of chemosensitivity tests: clonogenic assay versus MTT assay

When the development of chemotherapeutic agents reaches the clinical trial stage, it is necessary to perform drug sensitivity tests quickly in order to select the most promising agents for the treatment of cancer. In order to assess the possibility of using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay as a substitute for the human tumor clonogenic assay (HTCA), we evaluated the correlation between the results obtained by these 2 assays in 5 human lung cancer cell lines. The correlation coefficient between the results of the HTCA and the MTT assay was 0.673, indicating a relatively good correlation. The correlation was most prominent in platinum analogues (r = 0.939) and good in anthracyclines/anthracenedione (r = 0.611). However, no significant correlation was observed in vinca alkaloids, etoposide, irinotecan, SN-38 (an active metabolite of irinotecan), and rhizoxin. The results of the MTT assay showed a high degree of correlation with those of the HTCA in predicting the sensitivity of cancer cell lines to platinum analogues, and anthracyclines/anthracenedione. These results suggest that the MTT assay may be more convenient and quickly performed than the HTCA and can replace HTCA in evaluating the effects of anticancer agents, especially the platinum analogues and anthracyclines/anthracenedione.     

Effects of growth hormone treatment on thyroid function in pediatric patients with Prader–Willi syndrome

It is unclear whether hypothyroidism is present in patients with Prader–Willi syndrome (PWS). This study aimed to clarify the state of the hypothalamic–pituitary–thyroid axis and the effects of growth hormone (GH) treatment on thyroid function in pediatric patients with PWS. We retrospectively evaluated thyroid function in 51 patients with PWS before GH treatment using a thyroid‐releasing hormone (TRH) stimulation test (29 males and 22 females; median age, 22 months). We also evaluated the effect of GH therapy on thyroid function by comparing serum free triiodothyronine (fT3), free thyroxine (fT4), and thyroid stimulating hormone (TSH) levels at baseline, 1 year, and 2 years after GH therapy. TSH, fT4, and fT3 levels were 2.28 μU/ml (interquartile range [IQR]; 1.19–3.61), 1.18 ng/dl (IQR; 1.02–1.24), and 4.02 pg/dl (IQR; 3.54–4.40) at baseline, respectively. In 49 of 51 patients, the TSH response to TRH administration showed a physiologically normal pattern; in two patients (4.0%), the pattern suggested hypothalamic hypothyroidism (delayed and prolonged TSH peak after TRH administration). TSH, fT4, and fT3 levels did not change significantly during 1 or 2 years after GH treatment. The TSH response to TRH showed a normal pattern in most patients, and thyroid function did not change significantly during the 2 years after initiating GH treatment.