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At least 343 records · Page 19Linked to original sources
PubMed1986

The induction of supernumerary ribs in rodents: role of the maternal stress.

Increased incidences of supernumerary ribs (SNR) are a relatively common finding in standard teratology bioassays, and previous studies have indicated a possible correlation between their occurrence and general maternal stress. The present study describes the effects of immobilization stress on the induction of supernumerary ribs. To isolate the sensitive period of SNR induction, Sprague-Dawley rats and CD-1 mice were treated with 300 and 1,500 mg/kg, respectively, of sodium salicylate on single days 7-11 of gestation. In the rat, day 10 was found to be the sensitive period of lumbar rib induction (32% SNR vs 10% on other days) while day 9 was critical in the mouse (71% SNR vs less than 29% on other days). In a second set of experiments, maternal stress was accomplished by restraining two groups of gravid females in the supine position for 12 hours on the predetermined sensitive day. One group was immobilized from 9 am to 9 pm, while the second group was restrained from 9 pm to 9 am. Concurrent controls were food and water deprived for similar periods. Additional untreated controls were also included. An increase in supernumerary ribs was noted in stressed mice but not in rats. The 9 am to 9 pm mouse group exhibited the highest increase in supernumerary ribs (41%) as well as significant incidences of fused ribs and exencephaly. A significant linear relationship between maternal weight loss during treatment and increases in supernumerary ribs was also noted. Results suggest that for some compounds, supernumerary ribs may be the indirect result of agent-induced, generalized maternal stress in the CD-1 mouse.

Animals↗
PubMed2004

Does chronic cervical myelopathy affect respiratory function?

OBJECT: Although respiratory function is often impaired by acute cervical spinal cord injury, changes in respiratory function in patients with chronic cervical myelopathy (CCM) are not well documented. The purpose of this study was to evaluate the respiratory function of patients with CCM. METHODS: Spirometric parameters were measured in 94 patients with CCM before they underwent expansive laminoplasty. These measurements were compared with those obtained in age- and sex-matched control group patients without myelopathy. The study patients were also subdivided into two groups: those with spinal compressive lesions above or below the C3-4 disc level were compared in terms of respiratory function. The vital capacity values measured in patients with CCM were significantly lower than those in the control group. In patients in whom spinal cord compression was present above C3-4, vital capacity values were lower than in patients in whom the compression level was below C3-4. The resting respiratory rate per minute was elevated in the CCM group. Peak expiratory flow rate was significantly decreased, and expiratory velocities at 50 and 25% of vital capacity were significantly increased in the CCM group. CONCLUSIONS: The results indicated that expiratory flow may be impaired or incomplete in patients with CCM. An underlying subclinical respiratory dysfunction appears to be associated with CCM.

Adult↗
PubMedDate not supplied

Progressive osseous heteroplasia: an uncommon cause of ossification of soft tissues.

Whereas the deposition of calcium within soft tissues is not infrequent, the development of highly structured, mineralized tissue histologically identifiable as true bone is uncommon and can cause a variety of clinical features. This article reports the clinical and radiological features in a patient with progressive osseous heteroplasia (POH), a recently identified disorder characterized by heterotopic ossification. The patient, a female, was 20 years of age at presentation. In addition to abnormal ossifications, she had short metacarpals at the fourth and fifth rays and short metatarsals at the second rays. Her parents were unaffected. Until the results of Rosenfeld and Kaplan in 1995 reporting POH in two boys, typical features had only been reported in females (n=8). POH is usually sporadic; however, familial associations and atypical phenotypes have been reported.

Adult↗
PubMed2000

Morphological and physiological changes during growth: an update.

Skeletal growth and changes in body composition during growth present important variations; body mass index and lean body mass related to age show important gender differences. The process of ossification is developed in two different ways, endochondral and intramembraneous. The former is characterised by the formation of bone from growth cartilage. Intramembraneous ossification is characterised by the formation of bone from a mesenchymal structure, as occurs with the flat bones of the skull. During childhood and adolescence and up to the acquisition of adult stature, two phenomenons are produced simultaneously: the synthesis of new bone from growth cartilage due to the process of endochondral ossification, and modeling-remodeling of previously synthesized bone. Bone growth and mineralisation of its extracellular matrix are simultaneous phenomenons, the final result being the acquisition and maintenance of body bone mass. A positive calcium balance is necessary during adolescence in order to achieve the maximum peak of bone mass and even with the termination of longitudinal growth of bone, the process of mineralisation can last a further 4 years. Childhood and adolescence are the period of life in which the peak of bone mass must be achieved, and if during this time this does not happen there will be a greater risk for the later development of osteoporosis. Regulation of bone mass is a polygenic process and during recent years studies have been centred on the receptor genes of vitamin D and estrogens. A maximum calcium retention during adolescence may influence the achievement of a high peak of bone mass but at a certain level of calcium intake the calcium retention reaches a plateau. The expression of grams of hydroxyapatite per square centimetre has been used clinically, or expressed in volume as g/cm3. From birth until 3 years, the increase represents approximately 30% of the total increase, from 3 years until the beginning of pubertal development the increase is 20%. During pubertal development there is an increase of 30-40% and from the end of growth until the age of 21 years there is an increase of 15-20%. Both prepubertal boys and girls show a progressive increase of leptin levels during the years prior to the onset of puberty and until Tanner's stage 11 and higher levels are observed in girls in this period, possibly in relation to their earlier onset of puberty. This increase of leptin in girls during pubertal development suggests that leptin may be a link between adipose tissue and puberty.

Adolescent↗
PubMed2002

Ectopic mineralization of articular cartilage in the bullfrog Rana catesbeiana and its possible involvement in bone closure.

Mineralization of the articular cartilage is a pathological condition associated with age and certain joint diseases in humans and other mammals. In this work, we describe a physiological process of articular cartilage mineralization in bullfrogs. Articular cartilage of the proximal and distal ends of the femur and of the proximal end of the tibia-fibula was studied in animals of different ages. Mineralization of the articular cartilage was detected in animals at 1 month post-transformation. This mineralization, which appeared before the hypertrophic cartilage showed any calcium deposition, began at a restricted site in the lateral expansion of the cartilage and then progressed to other areas of the epiphyseal cartilage. Mineralized structures were identified by von Kossa's staining and by in vivo incorporation of calcein green. Element analysis showed that calcium crystals consisted of poorly crystalline hydroxyapatite. Mineralized matrix was initially spherical structures that generally coalesced after a certain size to occupy larger areas of the cartilage. Alkaline phosphatase activity was detected at the plasma membrane of nearby chondrocytes and in extracellular matrix. Apoptosis was detected by the TUNEL (TDT-mediated dUTP-biotin nick end-labeling) reaction in some articular chondrocytes from mineralized areas. The area occupied by calcium crystals increased significantly in older animals, especially in areas under compression. Ultrastructural analyses showed clusters of needle-like crystals in the extracellular matrix around the chondrocytes and large blocks of mineralized matrix. In 4-year-old animals, some lamellar bone (containing bone marrow) occurred in the same area as articular cartilage mineralization. These results show that the articular cartilage of R. catesbeiana undergoes precocious and progressive mineralization that is apparently stimulated by compressive forces. We suggest that this mineralization is involved in the closure of bone extremities, since mineralization appears to precede the formation of a rudimentary secondary center of ossification in older animals.

Age Factors↗
PubMed2006

Perlecan: how does one molecule do so many things?

Perlecan is a large multi-domain extracellular matrix proteoglycan that plays a crucial role in tissue development and organogenesis. In vertebrates, perlecan functions in a diverse range of developmental and biological processes, from the establishment of cartilage to the regulation of wound healing. How can a single molecule modulate such a wide variety of processes? We suggest that perlecan employs the same basic mechanism, based on interactions with growth factors, morphogens and matrix proteins, to regulate each of these processes and that the local extracellular environment determines the function of perlecan and consequently its downstream effects on the structure and function of the organ. We discuss this hypothesis in relation to its role in three major vertebrate developmental processes: angiogenesis, chondrogenesis and endochondral ossification.

Animals↗
PubMed2000

Stimulation of sodium-dependent phosphate transport and signaling mechanisms induced by basic fibroblast growth factor in MC3T3-E1 osteoblast-like cells.

Physiological and pathological observations indicate that basic fibroblast growth factor (bFGF) is an important regulator of osteoblastic cell differentiation and in particular of cranial ossification. Experimental evidence suggests that inorganic phosphate (Pi) transport could be an important function of bone matrix calcification. In the present study, we address the influence of bFGF on Pi transport activity in MC3T3-E1 osteoblast-like cells derived from mouse calvaria. The results indicate that bFGF is a potent and selective stimulator of sodium-dependent Pi transport in these cells. The change in Pi transport activity induced by bFGF depends on transcription and translation and corresponds to a change in the maximum velocity of the Pi transport system (Vmax). These observations suggest that enhanced Pi transport activity in response to bFGF may result from insertion of newly synthesized Pi transporters into the plasma membrane. A selective inhibitor of fibroblast growth factor receptor (FGFR) tyrosine kinase, SU5402, blunted the stimulation of Pi transport induced by bFGF. It also prevented the increase in protein tyrosine phosphorylation induced by bFGF, including phosphorylation of FGFR-1, FGFR-2, phospholipase C-gamma (PLC-gamma), and Shc as well as the recruitment of the Grb2/Sos signaling complex. In addition, bFGF-induced the activation of the mitogen-activated protein (MAP) kinases extracellular signal-regulated kinase (ERK) and p38, effects that were prevented by SU5402. Both the protein kinase C (PKC) inhibitor calphostin C and PKC down-regulation suppressed the stimulatory effect of bFGF on Pi transport. Selective inhibitors of ERK and p38 MAP kinases slightly reduced this cellular response with a significant effect observed with the highest concentration of the p38 MAP kinase inhibitor. In conclusion, the results of this study indicate that bFGF selectively stimulates Pi transport in calvaria-derived osteoblastic cells. The main signaling mechanism responsible for this effect involves tyrosine phosphorylation of PLC-gamma and activation of PKC, with a possible contribution of the p38 MAP kinase pathway.

3T3 Cells↗
PubMed1990

The development of centres of ossification of bones forming elbow joints in young swine.

Epiphyseal centres of ossification in the bones forming the elbow joints of pigs between one day and 15 weeks of age were examined radiographically, macroscopically, mesoscopically and microscopically. Thoracic limbs from 39 pigs were perfused with India ink or silicone rubber injection compound and the bones were dissected free of soft tissues. The humerus, ulna and radius were fixed in formalin or ethyl alcohol and then cleared by the modified Spalteholz technique. Bones were radiographed, examined grossly, and then cut into slabs for mesoscopical evaluation. Foci considered to be calcifying within cartilaginous anlage were selected for microscopical examination. It was concluded that the epiphyseal centre of ossification develops at different times in different sites in the bones forming the elbow joint. Centres of ossification are initiated when foci of chondrocytes adjacent to one side of a cartilage canal undergo hypertrophy and the inter-territorial matrix becomes calcified. Osteogenesis then proceeds in the calcified focus, presumably with osteoprogenitor cells that originate within the cartilage canals. Subsequently, each epiphyseal centre of ossification enlarges by one of two methods. Firstly, the layer of cartilage adjacent to the centre undergoes endochondral ossification, thus allowing for the circumferential growth of the epiphyseal centre of ossification. Secondly, foci of calcification develop adjacent to the ends of cartilage canals near the epiphyseal centre of ossification and eventually the focus of calcification coalesces with the developing epiphyseal centre of ossification, thus establishing a new ossification front. Endochondral ossification continues at the periphery of the mass of bone. Mesoscopical examination is more useful than radiographical evaluation for identifying small foci of calcification which precede epiphyseal centres of ossification.

Animals↗
PubMed1987

[Effects of overall food restriction on embryo-fetal development in the rat].

The effects of different levels of food restriction on the fetal-embryo development have been tested in rats (Sprague Dawley) weighing 250 g. Experimental groups received 100 (control), 75, 50 or 25% of mean daily consumed food containing 17% of proteins, either from the coupling (Day 1) or from the nestling (Day 6) and till the sacrifice (Day 21). The weight of the mothers and the fetus is diminished in function of the degree and the duration of the food restriction. The study of the maternal growth shows an adaptation to the food restriction as well as the pregnancy anabolism. The last one is not observed in the females presenting an early embryonic mortality. The nestling is not affected in any of the groups and the embryonic mortality is only observed at the highest restricted level in 1/10 female restricted from Day 6 on and in 5/10 of the rats restricted from Day 1 on. In these last ones, the emaciation between Day 1 and Day 21 after hysterectomy is 37% and the growth of the surviving fetuses is only 40% of the controls. Embryonic mortality most often precocious (before the 10th Day) shows a phenomenon of "all or none" and touches the entire litter of the females concerned; the others maintain a normal pregnancy. The fetal growth seems privileged as compared with the maternal growth. These restrictions have neither influenced the sex ratio, nor induced any specific teratogenic effect: the delayed ossification seems to be expressed precociously on the 5th sternebra.

Animal Nutritional Physiological Phenomena↗
PubMed1986

[A study on the effect of (2"R)-4'-O-tetrahydropyranyladriamycin, a new antitumor antibiotic, on reproduction. III. Its effects on perinatal and postnatal rats].

This paper describes effects of (2"R)-4'-O-tetrahydropyranyladriamycin hydrochloride (THP) on perinatal and postnatal rats. The drug was administered intravenously to female rats at 0.01, 0.03 or 0.1 mg/kg daily from day 17 of pregnancy to 21 days after delivery. Results were described below. At any dose levels tested, THP did not affect the body weight gain, food and water consumption by pregnant rats, and length of gestation period or delivery rate. However, at the highest dose level, THP decreased spleen weight. THP, at any dose levels, did not have toxic effect on development, physiological functions, behavior, mating, fertility or pregnancy of the first generation offspring (F1). At the highest dose of 0.1 mg/kg, however, THP produced delayed ossification of sacrococcygeal vertebra in the second generation fetuses (F2). The results suggest that the maximum "no effect" dose of THP to pregnant rats and offsprings is 0.03 mg/kg/day intravenously.

Animals↗
PubMed2002

Osteochondrosis of the primary ossification center of the patella (Köhler's disease of the patella) report of three cases.

Radiography of three boys 5-6 years old with anterior knee pain revealed increased density and irregularity of the patellar ossification centers. A search of the literature suggested that it was osteochondrosis of the primary ossification center of the patella, named after Köhler. Continuing search also revealed that it might be a normal variant instead of an osteochondrosis. A short course of activity modification led to marked improvement in all. The patients were either asymptomatic or experienced minor symptoms 18-34 months after presentation. It was concluded that the process, either physiological or pathological, has a benign course and favorable prognosis.

Child↗