Takeaki Inomoto

Correlation between forearm bone mineral density and body composition in Japanese females aged 18–40 years

ObjectiveThe purpose of this study was to clarify the relationship between forearm bone mineral density (BMD), body mass index (BMI), and body composition focusing on body fat percentage (BF%) in Japanese females 18 to 40 years old.MethodsSubjects were 2,280 females 18–40 years old. Anthropometric measurements were taken, and a medical history was obtained by questionnaire, including age at the time of the study and age at menarche. BF% was measured by bioelectrical impedance analysis. Forearm BMD was measured using dual-energy X-ray absorptiometry (DXA). The correlations of BMD with BMI and BF% were analyzed using a structural equation model.ResultsThe standardized regression coefficients for the path from BMI to BMD and the path from BF% to BMD were 0.538 and −0.184 respectively. The squared multiple correlation of BMD was 0.146. In addition, the standardized regression coefficient for the path from BMI to BF% was 0.896.ConclusionThe results showed a positive correlation between BMD and BMI and an inverse correlation between BMD and BF%. At the same time, it was noted that BF% increased with BMI. This indicated that BMD is dependant on BF% in subjects who have a similar BMI. Therefore, this study concluded that it is necessary to take body composition measurements into account when examining the relationship between BMI and BMD, especially in young females.

A Potential Animal Model for Familial Amyloidotic Polyneuropathy Through Introduction of Human Mutant Transthyretin Gene Into Mice

Familial amyloidotic polyneuropathy (FAP) has been identified in a number of kindreds of the world. FAP is an autosomal dominant disorder characterized by extracellular deposition of fibrillar amyloid protein and by prominent peripheral nerve involvement (1–4). This protein is mainly composed of TTR with a substitution of methionine for valine at position 30 in the FAP type I, as reported in Japan, Sweden and Portugal (5–7). This amino acid substitution is thought to lead to amyloid deposition. The human TTR gene has been cloned and well characterized at the molecular level (8, 9). All the FAP patients so far examined carry one mutant gene (10, 11). However in patients with FAP, the age at onset varies from 20 to 45 years. In addition the clinical syndrome is variable even among kindreds with the same genetic defect. These data suggest involvement of factor(s) other than the single nucleotide mutation in the TTR gene. To elucidate this factor(s) and to examine the pathological process of amyloid deposition, we have produced transgenic mice by microinjecting the cloned human mutant TTR gene into fertilized eggs of C57BL/6 mice.

Expression of tissue-specific genes in transgenic mice.

The ability to introduce cloned genes into mouse germ line has been used for analyzing cis-acting DNA sequences involved in tissue-specific and developmental regulation of the introduced gene. Using this system we have attempted to produce a transgenic mouse model for human dominantly inherited disease, familial amyloidotic polyneuropathy. Recently the mutant transthyretin gene which is considered to be responsible for this disease has been cloned and well characterized at molecular level. We have produced transgenic mice by microinjecting human mutant gene. Amyloid deposition was observed in the mucosa of alimentary tract and renal glomeruli, suggesting that this approach is successful in establishing the mouse model for human genetic disease. In addition, these experiments suggest that the expression of the mutant gene is regulated normally during developmental process and that the cause of adult onset is not due to the dysregulation of this gene expression.

A study on the work load of recent forestry work.

著しく機械化が進行し, かつての労働態様とは一変したとされる今日の林業の労働負担について, 全面的に機械化されている民間林業と振動障害予防の観点から一部手工具による作業が行なわれている国有林で調査を行なった。その結果, 全面的に機械化されていない国有林労働の主な作業別のエネルギー消費量では伐木の際の斧による受口切り, 斧による枝払い, 機械化されている民間林業では, 集材の際の玉かけが5-7kcal/分と比較的大きく, とくに時間配分 (150-200分) や安全性を考慮すれば斧による枝払いは早急に改善する必要があると思われた。作業前後の血清sarcoplasmicenzymeや尿中カテコールアミンの変動をみると, 民間, 国有林のいずれの場合も, 先山作業で血清CPK, LDHが有意に増加し, 今日でもなお林業労働ではglycogenesisの変動をもたらす要因のあることが示唆された。また, 先山作業, 盤台作業ともに尿中VMA, ノルアドレナリンの著明な変動がみられ, 危険でストレスの多い林業労働の本質は残っていること, これらの林業労働の特質についてさらに労働生理学的研究が必要であることを報告した。