Studies were conducted to quantitate histological age changes in human bone cortex. Ground (undecalcified ) and decalcified cross sections of mandible, femur and tibia were measured for: (1) number of osteons in two ficlds, ( 2 ) average number of lamellae per osteon, and ( 3 ) average Haversian canal diameter. These data were obtained from 59 subjects (52 males) ranging in age from 39 to 87 years. Multiple regression techniques were then utilized to estimate age at death from several combinations of these measurements. With age, the number of osteons per unit area of bone and the number of lamellae per osteon increased but Haversian canal diameter decreased. The number of lamellae per osteon had the least significant correlation with age. Multiple regression analyses indicated that in this age group age at death could be estimated to within six years of the true value in 95% of human males. Histological measurements of the mandible provided estimates that were consistently more accurate than those based on the two long bones. A monograph, prepared from mandibular measurements, can be used to estimate age at death between 40 and 80 years of age in the male human population. Significant sex differences were not noted and racial differences were not analyzed. I t was concluded that, compared to existing morphologic methods, microstructure of bone cortex can be quantitated to estimate age at death more accurately. More extensive studies o n race, sex and metabolic influences on age estimation from different bones would have important medico-legal and anthropologic implications. The experimental approach utilized here should also be useful in diagnostic pathology and in ageing research.
A mutation (C677T) in the gene, MTHFR, is known to increase susceptibility to various multifactorial disorders. In order to assess this single nucleotide polymorphism (SNP) as risk factor for idiopathic male infertility, a case-control study was done on an Indian population. DNA from 151 cases of non-obstruction, idiopathic oligo-/azoospermia and 200 fertile males (controls) was polymerase chain reaction amplified using site-specific primers, and analysed for the mutation following HinfI-digestion. Our results show a significantly increased frequency of CT heterozygotes among infertile patients (p value <0.04). More importantly, while there were no T homozygotes in the control population, six of 151 infertile cases were T homozygous. Considering that T allele occurs in very low frequency in the control population, 677T is clearly a risk factor for infertility in the Indian population. We contend that the same could also be true for African and Southeast Asian populations where the frequency of 677T is very low. The lack of similar association in western populations could be because of the overall dietary enrichment of folates, which could nullify or minimize the effect of this polymorphism.
This report adds to the available information on comparative histology of mammalian bone and introduces a semi-quantitative approach to its study. Bone samples consisted of large fragments of rib tibia and/or femur from humans, laboratory rodents and from animals that died at the Bronx Zoological Gardens. A total of 44 bone specimens representing six mammalian orders were available. Decalcified paraffin-embedded 10 pm histological cross-sections were examined at x 320. Qualitative observations were supplemented with measurements of the frequency and size distributions of Haversian and non-Haversian canals. The relative distribution of lacunae was also ascertained. The standard textbook description of mammalian bone as consisting mainly of secondary osteons was not generally seen except in Primate (especially human) bone. Rats showed a few scattered osteon-like structures, but bones of Marsupialia, Insectivora, Artiodactyla and Carnivora were entirely devoid of them. Generally, vascular bone with longitudinal canals was seen except in Lorisidae which showed a reticular type of bone. The distribution of primary longitudinal canals and the number of "filled' or "apparently empty" lacunaelunit area of bone varied both inter-species and among different areas in the same bone. Large areas of acellular and non-vascular bone were encountered in all specimens. This preliminary study revealed that species differences in bone microstructure involve the relative distribution of the same basic components which lend themselves to quantitative treatment. Comparative investigations of bone histology at many ontogenetic and phylogenetic levels should yield significant quantitative information in bone biology.
The effects of cold-stress and hibernation on bone dynamics in the femurs of hamsters were investigated using histometric analyses. Control animals were maintained at 27 degrees C for 90 days; experimental animals were kept at 5 degrees C and hibernated for 7, 15, 21, 50, or 90 days. Histometric analyses of cross sections indicated that bone diameter and cortical thickness at the femoral midshaft increased after 83 days of extreme cold and 7 days of hibernation but decreased significantly after 69 days of cold stress and 21 days of hibernation. Osteoporosis was evident although the number of osteons per unit area of bone increased during hibernation. An initial decrease in the number of non-Haversian longitudinal vessels per unit area of bone was seen in experimental animals which was apparently related to a corresponding reduction in cortical thickness. Lacunar area increased in these animals, suggesting that osteocytic osteolysis may be a significant mechanism for calcium regulation during hibernation.
Sympathectomy was carried out in 4-week-old Sprague-Dawley rats by unilateral surgical removal of the superior cervical ganglion. Sham-treated rats served as controls. All rats were injected with tetracycline hydrochloride at surgery as well as 36 hr prior to sacrifice. Rats were killed at 7, 14, or 21 days following sympathectomy. Mandibular periosteal and endosteal surfaces were analyzed by fluorochrome morphometry. Osteoclasts were identified by acid phosphatase staining, and incisor and molar root sockets were analyzed morphometrically. Following sympathectomy, periosteal and endosteal apposition as well as the rate of mineralization were significantly lower. At the same time, a significant increase in the number of osteoclasts per socket as well as in active and inactive bone resorption surfaces was also seen. All parameters, however, returned to normal values 2-3 weeks after sympathectomy. The data provide the first direct quantitative evidence that sympathetic neurons modulate bone resorption and bone remodeling in vivo.
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