No effect of risedronate on articular cartilage damage in the Dunkin Hartley guinea pig model of osteoarthritis.

Objectives: To investigate whether treatment with a bisphosphonate would influence the subchondral bone plate stiffness and the development of cartilage damage in Dunkin Hartley guinea pigs, which develop osteoarthritis (OA) spontaneously.

Method: Fifty-six 3-month-old male Dunkin Hartley guinea pigs were randomized into a baseline group and six groups receiving either the bisphosphonate risedronate (30 µg/kg) or vehicle five times a week for 6, 12, or 24 weeks. The medial condyle of the right stifle joint was investigated by histology, using the Osteoarthritis Research Society International (OARSI) score, along with static and dynamic histomorphometry.

Relationship between articular cartilage damage and subchondral bone properties and meniscal ossification in the Dunkin Hartley guinea pig model of osteoarthritis.

Objectives: To describe the age-related changes of articular cartilage, subchondral bone morphology, and stiffness. Furthermore, to investigate whether subchondral bone histological and mechanical properties and meniscal histological properties are related to articular cartilage damage in the Dunkin Hartley guinea pig model of osteoarthritis (OA).

Methods: Forty male Dunkin Hartley guinea pigs aged 2, 6, 9, and 12 months were studied.

Cervical collagen and biomechanical strength in non-pregnant women with a history of cervical insufficiency.

Background: It has been suggested that cervical insufficiency (CI) is characterized by a "muscular cervix" with low collagen and high smooth muscle concentrations also in the non-pregnant state. Therefore, the aim of this study was to investigate the biomechanical properties, collagen concentration, smooth muscle cell density, and collagen fiber orientation in cervical biopsies from non-pregnant women with a history of CI.

Methods: Cervical punch biopsies (2 x 15 mm) were obtained from 57 normal non-pregnant women and 22 women with a history of CI.

Collagen concentration and biomechanical properties of samples from the lower uterine cervix in relation to age and parity in non-pregnant women.

Background: During normal pregnancy the cervix has a load bearing function. The cervical tissue consists mainly of an extracellular matrix (ECM) rich in collagen; important for the biomechanical properties. The aim of the present study was to evaluate how the biomechanical strength of samples from the distal cervix is associated with collagen content in relation to age and parity.

Strontium and bone nanostructure in normal and ovariectomized rats investigated by scanning small-angle X-ray scattering.

The effect of SrCl(2) treatment on bone nanostructure in a rat ovariectomy model was studied using scanning small-angle X-ray scattering (sSAXS). Twelve 6-month-old female Wistar rats were used. Six animals were ovariectomized (+ovx) and six were left intact after sham surgery (-ovx).

T-tube drainage stimulates the healing of choledocho-choledochostomies. An experimental study in pigs.

Background/purpose: We investigated the effect of T-tube drainage on the healing of choledocho-choledochostomies in pigs.

Methods: Twenty pigs with a median weight of 56 kg were used for the experiments. The pigs were randomized to two groups of ten.

Choledocho-choledochostomy: the natural history of healing in pigs.

Background/purpose: Aiming to investigate the natural history of the healing of choledocho-choledochostomies.

Methods: Fifty-five female pigs of 57 kg median weight were used for the experiments. The gallbladder was removed and the common bile duct transected.

The anabolic effect of PTH on bone is attenuated by simultaneous glucocorticoid treatment.

Glucocorticoids (GC) are used for the treatment of a wide spectrum of diseases because of their potent anti-inflammatory and immunosuppressive effects, and they are serious and common causes of secondary osteoporosis. Administration of intermittent parathyroid hormone (PTH) may induce formation of new bone and may counteract the bone loss induced by GC treatment. Effects of simultaneous PTH and GC treatment were investigated on bone biomechanics, static and dynamic histomorphometry, and bone metabolism.

The influence of ultrasound on the mechanical properties of healing tendons in rabbits.

Background: Therapeutic ultrasound is commonly used for treatment of injuries to tendons, ligaments and joint capsules. Opinions still differ, however, as to the beneficial effects of ultrasound treatment of the above-mentioned conditions.

Methods: We studied the effect of various ultrasound intensities on the healing of tenotomized, sutured and immobilized Achilles tendons of adult rabbits.

The total length of myocytes and capillaries, and total number of myocyte nuclei in the rat heart are time-dependently increased by growth hormone.

Growth hormone (GH) can increase size and dimensions of rat hearts. The aim was to study how GH administration influences the growth of cardiac myocytes and capillaries in relation to time. Three-month-old female rats were divided into 10 groups (n=3), and injected with either GH (5mg/kg/day) or vehicle for 5, 10, 20, 40, or 80 days.

Subchronic toxicity of baltic herring oil and its fractions in the rat (III) bone tissue composition and dimension, and ratio of n-6/n-3 fatty acids in serum phospholipids.

Changes in total bone mineral density determined by the bone-ash method were recently demonstrated in rats, exposed to Herring oil from the contaminated southern part of the Baltic Sea. In the present study more detailed analysis of bone structure and biomechanics was performed and obtained results were evaluated in the context of dietary factors, such as polyunsaturated fatty acids, vitamin D and vitamin A. Baltic Sea herring oil was fractionated into one relatively pollutant-free fraction (F1), and two fractions with pronounced enrichment of pollutants (F2 and F3).

The effects of growth hormone on cortical and cancellous bone.

Growth hormone (GH) has profound effects on linear bone growth, bone metabolism and bone mass. The GH receptor is found on the cell surface of osteoblasts and osteoclasts, but not on mature osteocytes. In vitro, GH stimulates proliferation, differentiation and extracellular matrix production in osteoblast-like cell lines.

Growth hormone can reverse glucocorticoid-induced low bone turnover on cortical but not on cancellous bone surfaces in adult Wistar rats.

Unlabelled: We evaluated the effect of glucocorticoids (GC) and growth hormone (GH) on cortical and cancellous bone turnover in adult rats using random vertical sections giving valid measurements of bone surfaces and bone formation parameters. GH administration could reverse GC-induced osteopenia and low bone turnover of cortical bone. However, GH could not reverse the GC-induced low bone turnover of cancellous bone.

Biphasic effect of relaxin, inhibitable by a collagenase inhibitor, on the strength of human fetal membranes.

Background: Relaxin has been proposed as a hormone involved in the collagen remodeling of the utero-placental unit.

Materials And Methods: Human fetal membrane explants were incubated with H1 or H2 relaxin for 48 hours and stretched until rupture in a materials testing machine. Co-incubation with a synthetic collagenase inhibitor was performed in order to examine whether the effects of relaxin could be inhibited.

Simvastatin treatment partially prevents ovariectomy-induced bone loss while increasing cortical bone formation.

Statins are commonly prescribed drugs that inhibit hepatic cholesterol synthesis and thereby reduce serum cholesterol concentrations. Some of the statins are thought to possess bone anabolic properties. Effects of statin on tibia, femur, and vertebral cortical and cancellous bone were studied in ovariectomized (OVX) rats.

Local anabolic effects of growth hormone on intact bone and healing fractures in rats.

The local effects of rat growth hormone (rGH) injected at the surfaces of intact tibial diaphyses and healing tibial diaphysial fractures were investigated in 10-month-old female rats. Intact diaphysial bones: rats were injected daily for 14 days with vehicle, 2 microg rGH, or 20 microg rGH at the surface of the right tibial diaphysis. After 10 days of injection the animals were labeled with calcein.

Low-intensity, high-frequency vibration appears to prevent the decrease in strength of the femur and tibia associated with ovariectomy of adult rats.

The effect of low-intensity, high-frequency vibration on bone mass, bone strength, and skeletal muscle mass was studied in an adult ovariectomized (OVX) rat model. One-year-old female rats were allocated randomly to the following groups: start control, sham OVX, OVX without vibration, OVX with vibration at 17 Hz (0.5g), OVX with vibration at 30 Hz (1.

Subclinical hypervitaminosis A causes fragile bones in rats.

Excessive intake of vitamin A has been associated with an increased risk of hip fracture in humans. This finding has raised the question of whether long-term intake of relatively moderate doses ("subclinical" hypervitaminosis A) contributes to fracture risk. Although it has been known for more than half a century that toxic doses of vitamin A lead to spontaneous fractures in rats, the lowest intake that induces adverse effects is not known, and the result of exposure to excessive doses that do not cause general toxicity has been rarely investigated.

Growth hormone increases the total number of cardiac myocyte nuclei in young rats but not in old rats.

Previously we have shown that growth hormone (GH) increases the total number of myocyte nuclei of the left ventricle in adult rats (8 months old). In the present study, we investigated whether GH could increase the total number of myocyte nuclei of the left ventricle in young and old rats. Female rats, 3 months old and 20 months old, were injected with GH or vehicle for 80 days.

An intraluminal prosthesis may improve healing of a one-layer colonic anastomosis: an experimental study in pigs.

Objective: To compare healing of one-layer colonic anastomoses with or without a soluble intraluminal prosthesis (* SBS-tube).

Design: Randomised, partly blinded controlled study.

Setting: University hospital, Denmark.

Growth hormone increases the total number of myocyte nuclei in the left ventricle of adult rats.

Several studies have shown that growth hormone (GH) administration can increase size and dimensions of rat hearts. The aim of the present study was to evaluate the effect of GH on the growth of myocytes, myocyte nuclei, connective tissue, connective tissue nuclei and capillaries in the adult rat heart with special reference to total number, total length and total and relative volumes. Eight-month-old female rats were injected with either GH or vehicle for 80 days.

Parathyroid hormone induces formation of new cancellous bone with substantial mechanical strength at a site where it had disappeared in old rats.

Objective: The present study addresses the question--can PTH induce formation of trabeculae in areas where cancellous bone has disappeared? Two-year-old male rats were chosen, because in this aged animal model the distal femurs have almost no cancellous bone, and the marrow cavity has reached a substantial dimension.

Design: The rats were injected for 56 days with either PTH(1-34), 15 nmol/kg/day (62.5 microg/kg/day), or vehicle.

Growth hormone influences the content and composition of collagen in the aorta from old rats.

Collagen and elastin are major components of the aortic extracellular matrix and crucial in determining the stiffness of the aorta. We recently showed that growth hormone (GH) changes the mechanical properties, content and composition of aortic collagen from young rats. In the present study, the effect of GH on aorta from old rats was investigated.

Statin given perorally to adult rats increases cancellous bone mass and compressive strength.

Recently, it has been shown that statins increased cancellous bone formation and volume in 3-month-old rats and induced a minor decrease in osteoclast number. In the present study, one-year-old female rats were given simvastatin (10 mg/kg) or placebo daily for 3 months by a gastric tube. Specimens, 2.

The growth hormone secretagogue ipamorelin counteracts glucocorticoid-induced decrease in bone formation of adult rats.

The ability of the growth hormone secretagogue (GHS) Ipamorelin to counteract the catabolic effects of glucocorticoid (GC) on skeletal muscles and bone was investigated in vivo in an adult rat model. Groups of 8-month-old female rats were injected subcutaneously for 3 months with GC (methylprednisolone) 9 mg/kg/day or GHS (Ipamorelin) 100 microg/kg three times daily, or both GC and GHS in combination. The maximum tetanic tension of the calf muscles was determined in vivo in a materials testing machine.