Tissue ingrowth into titanium and hydroxyapatite-coated implants during stable and unstable mechanical conditions

Lack of initial mechanical stability of cementless prostheses may be responsible for fibrous tissue fixation of prosthetic components to bone. To study the influence of micromovements on bony ingrowth into titanium alloy (Ti) and hydroxyapatite (HA)-coated implants, a loaded unstable device producing movements of 500 microns during each gait cycle was developed. Mechanically stable implants served as controls. The implants were inserted into the weight-bearing regions of all four femoral condyles in each of seven mature dogs. Histological analysis after 4 weeks of implantation showed a fibrous tissue membrane surrounding both Ti and HA-coated implants subjected to micromovements, whereas variable amounts of bony ingrowth were obtained in mechanically stable implants. The pushout test showed that the shear strength of unstable Ti and HA implants was significantly reduced as compared with the corresponding mechanically stable implants (p less than 0.01). However, shear strength values of unstable HA-coated implants were significantly greater than those of unstable Ti implants (p less than 0.01) and comparable to those of stable Ti implants. The greatest shear strength was obtained with stable HA-coated implants, which was threefold stronger as compared with the stable Ti implants (p less than 0.001). Quantitative determination of bony ingrowth agreed with the mechanical test except for the stronger anchorage of unstable HA implants as compared with unstable Ti implants, where no difference in bony ingrowth was found. Unstable HA-coated implants were surrounded by a fibrous membrane containing islands of fibrocartilage with higher collagen concentration, whereas fibrous connective tissue with lower collagen concentration was predominant around unstable Ti implants. In conclusion, micromovements between bone and implant inhibited bony ingrowth and led to the development of a fibrous membrane. The presence of fibrocartilage and a higher collagen concentration in the fibrous membrane may be responsible for the increased shear strength of unstable HA implants. Mechanically stable implants with HA coating had the strongest anchorage and the greatest amount of bony ingrowth.

Human parathyroid hormone (1-34) and (1-84) increase the mechanical strength and thickness of cortical bone in rats

An anabolic effect on bone of intermittent parathyroid hormone (PTH) treatment has been found in patients with osteoporosis and also in experimental animals. Controversies exist, however, about whether the positive effect on the trabecular bone balance occurs at the expense of the cortical bone. We examined the biomechanical quality of cortical bone after intermittent treatment with different doses of PTH and, furthermore, compared the effects of PTH-(1-34) and PTH-(1-84). Groups of rats were treated with biosynthetic human PTH-(1-34) or PTH-(1-84), 1.1, 3.3, 10, or 30 nmol/kg/day for 30 days. No changes in the body weights and no changes in the lengths of the femora were observed after the PTH treatments. The biomechanical properties were analyzed by means of a materials-testing machine. A dose-related increase in the bending strength and stiffness of the femora was found, and this increase in mechanical strength corresponds with a 9-12% increase in the cross-sectional area of the femoral diaphyses. The deflection capability and energy absorption were not influenced by any of the PTH treatments. No differences were found between the effects of PTH-(1-34) or PTH-(1-84) on the biomechanical properties of the femora. Consequently, intermittent treatment with biosynthetic PTH-(1-34) or PTH-(1-84) increased the formation of cortical bone, and the biomechanical competence of the femora was found to be preserved.

Detection and subtyping (H5 and H7) of avian type A influenza virus by reverse transcription-PCR and PCR-ELISA

Avian influenza virus infections are a major cause of morbidity and rapid identification of the virus has important clinical, economical and epidemiological implications. We have developed a one-tube Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) for the rapid diagnosis of avian influenza A. A panel of reference influenza strains from various hosts including avian species, human, swine and horse were evaluated in a one tube RT-PCR using primers designed for the amplification of a 218 bp fragment of the NP gene. The PCR products were detected by PCR-ELISA by use of an internal catching probe confirming the NP influenza A origin. The PCR-ELISA was about 100 times more sensitive than detection of PCR products by agarose gel electrophoresis. RT-PCR and detection by PCR-ELISA is comparable in sensitivity to virus propagation in eggs. We also designed primers for the detection of the influenza. A subtypes H5 and H7 shown to have pathogenic potential in poultry. The H5 primers cover the cleavage site of the HA gene and specifically amplify influenza A subtype H5. The H7 primers also cover the HA cleavage site and detected all H7 reference strains investigated. In addition, the H7 primers also amplified very weak and/or additional bands on an agarose gel from other subtypes. However, the H7 origin and the pathogenic potential defined by the presence or absence of basic amino acids at the cleavage site can be determined by sequencing of the PCR product. As far as we know this is the first demonstration of RT-PCR detection on a panel of H7 strains using only one primer set.

Growth hormone stimulates bone formation and strength of cortical bone in aged rats

The influence of growth hormone on bone formation, mechanical strength, and composition has been investigated in femur middiaphyseal cortical bone from 2-year-old male rats. The rats were given biosynthetic human growth hormone (bhGH) at 2.7 mg/kg/day in two daily injections for 20, 40, or 80 days, and all animals were killed 80 days after the start of bhGH administration. Control animals were given saline. All animals were labeled with tetracycline on days 41 and 69. Only in the bhGH-80-day group was subperiosteal tetracycline double labeling seen all around the femur diaphysis, and this pattern was found in all animals of the group. Double labeling subperiosteally at the posteromedial aspect was found in all animals of the experiment, but compared with the control group, a 400% and an 800% increase in mineral apposition rate was seen in the bhGH-40-day and bhGH-80-day groups, respectively. Light microscopy and polarization microscopy showed that this newly deposited bone was organized in the same concentric lammellae and had the same direction of the collagen fibers when compared with the surrounding bone formed before the start of bhGH injections. The cortical bone cross-sectional area was increased in the bhGH-40-day and bhGH-80-day groups. At the endosteum, scattered labeling was found in animals from all groups, and no differences in medullary cross-sectional areas were seen. The mechanical analysis revealed an increased mechanical strength of the whole diaphyseal bone after bhGH administration. When the data were corrected for dimensions of the diaphyseal bone, no differences in intrinsic mechanical properties of the bone tissue were found. No differences in apparent density of dry defatted bone, ash, and collagen were seen, whereas apparent density of dry defatted bone minus ash was decreased in all groups given bhGH. Correspondingly, a slight increase in ash concentrations of the bhGH-injected animals was seen. bhGH administration also increased the body weight, muscle mass, and total serum IGF-I and thyroxine concentrations.

Identification of Sensitive and Specific Avian Influenza Polymerase Chain Reaction Methods Through Blind Ring Trials Organized in the European Union

Many different polymerase chain reaction (PCR) protocols have been used for detection and characterization of avian influenza (AI) virus isolates, mainly in research settings. Blind ring trials were conducted to determine the most sensitive and specific AI PCR protocols from a group of six European Union (EU) laboratories. In part 1 of the ring trial the laboratories used their own methods to test a panel of 10 reconstituted anonymized clinical specimens, and the best methods were selected as recommended protocols for part 2, in which 16 RNA specimens were tested. Both panels contained H5, H7, other AI subtypes, and non-AI avian pathogens. Outcomes included verification of 1) generic AI identification by highly sensitive and specific M-gene real-time PCR, and 2) conventional PCRs that were effective for detection and identification of H5 and H7 viruses. The latter included virus pathotyping by amplicon sequencing. The use of recommended protocols resulted in improved results among all six laboratories in part 2, reflecting increased sensitivity and specificity. This included improved H5/H7 identification and pathotyping observed among all laboratories in part 2. Details of these PCR methods are provided. In summary, this study has contributed to the harmonization of AI PCR protocols in EU laboratories and influenced AI laboratory contingency planning following the first European reports of H5N1 highly pathogenic AI during autumn 2005.

Mechanical properties and biochemical composition of rat cortical femur and tibia after long-term treatment with biosynthetic human growth hormone

The influence of biosynthetic human growth hormone (b-hGH) on female rat cortical femur and tibia was studied after administration of hormone doses of 0.16, 1.10, or 8.33 mg/kg body weight/day for 90 days. The mechanical properties, dimensions, real density, ash weight, and the mineral and collagen concentrations of the bones were measured. In both femur and tibia a positive linear relation was found between the dose of hormone and ultimate load, ultimate stiffness, energy absorption at ultimate load, load at failure, energy absorption at failure, and deflection at failure. In the femur a positive correlation between dose and deflection at ultimate load was also found. After normalizing the mechanical data for the dimensions of the bones, no differences were found in the hormone treated groups compared to placebo, except for the elastic modulus (Young's modulus), which was decreased in the femur in the group given 8.33 mg b-hGH. The mineral and collagen concentration were unaffected in both femur and tibia, whereas the real density was decreased in the femur. The growth-hormone-induced changes in the mechanical properties seem to be caused mainly by increased dimensions of the bones.

Transcriptional profiles of chicken embryo cell cultures following infection with infectious bursal disease virus

Infectious bursal disease virus (IBDV) is the causative agent of infectious bursal disease in chickens and causes a significant economic loss for the poultry industry. Little is understood about the mechanism involved in the host responses to IBDV infection. For better understanding the IBDV-host interaction, we measured steady-state levels of transcripts from 28 cellular genes of chicken embryo (CE) cell cultures infected with IBDV vaccine stain Bursine-2 during a 7-day infection course by use of the quantitative real-time RT-PCR SYBR green method. Of the genes tested, 21 genes (IRF-1, IFN 1-2 promoter, IFNAR-1, IRF-10, IFN-gamma, 2',5'-OAS, IAP-1, caspase 8, TRAIL-like, STAT-3, IL-6, IL-8, MIP-3 alpha, MHC-I, MHC-II, TVB, GLVR-1, OTF, IL-13R alpha, ST3GAL-VI and PGK) showed an increased expression. The remaining seven genes (IFNAR-2, IFN-alpha, NF-kappaB subunit p65, BLRcp38, DDX1, G6PDH and UB) showed a constant expression or only slight alteration. Apparently, the host genes involved in pro-inflammatory response and apoptosis, interferon-regulated proteins, and the cellular immune response were affected by IBDV infection, indicating involvement in the complex signaling pathways of host responses to the infection. This study thus contributes to the understanding of the pathogenesis of IBD and provides an insight into the virus-host interaction.

Fixation of osteochondral fractures. Fibrin sealant tested in dogs

Standardized osteochondral fractures in the left femoral condyle in 19 adult mongrel dogs were fixed with either fibrin sealant or Kirschner wire. Adaptation and mechanical strength after 4, 7 or 8, and 14 days were compared with an in vitro study of the initial strength of the fibrin sealant in osteochondral fractures. After 4 days, the maximum tensile strength was increased in the fibrin sealed group, whereas no difference in energy absorption at failure was found. Although the initial strength of the fibrin bond was low, the tendency to displacement was less in this group. Our results suggest that fibrin sealant can be used for fixation of small osteochondral fragments, provided that immobilisation is sufficient.

Dose response of growth hormone on fracture healing in the rat

The effect of different doses of biosynthetic human growth hormone on the mechanical properties of tibial fractures and intact bones was studied in a rat model; a three-point bending test was applied 40 days after fracturing. Ninety-day-old female rats received a daily dose of 0, 0.08, 0.4, 2.0, or 10 mg of growth hormone/kg body weight starting 1 week before fracture and continuing until mechanical testing. In the animals given 2.0 and 10 mg of hormone, the ultimate load sustained by the fractures, stiffness, and energy absorption at ultimate load increased, while the ultimate stress increased only in the latter groups. In the intact bones, ultimate load of the bones increased in the same groups, while stiffness and energy absorption at ultimate load increased only in the group given the highest dose of hormone.

Reverse shoulder replacement after resection of the proximal humerus for bone tumours

We investigated the functional outcome in patients who underwent reverse shoulder replacement (RSR) after removal of a tumour of the proximal humerus. A total of 16 patients (ten women and six men) underwent this procedure between 1998 and 2011 in our hospital. Five patients died and one was lost to follow-up. Ten patients were available for review at a mean follow-up of 46 months (12 to 136). Eight patients had a primary and two patients a secondary bone tumour. At final follow up the mean range of active movement was: abduction 78° (30° to 150°); flexion 98° (45° to 180°); external rotation 32° (10° to 60°); internal rotation 51° (10° to 80°). The mean Musculoskeletal Tumor Society score was 77% (60% to 90%) and the mean Toronto Extremity Salvage Score was 70% (30% to 91%). Two patients had a superficial infection and one had a deep infection and underwent a two-stage revision procedure. In two patients there was loosening of the RSR; one dislocated twice. All patients had some degree of atrophy or pseudo-atrophy of the deltoid muscle. Use of a RSR in patients with a tumour of the proximal humerus gives acceptable results.

Increased mechanical strength of healing rat tibial fractures treated with biosynthetic human growth hormone

The effects of biosynthetic human growth hormone on the biomechanical properties of healing tibial fractures and intact bones in the rat were studied after 20 and 40 days of healing. Growth hormone, 2.0 mg per kg per day, was given subcutaneously in two daily doses. Control animals were injected with a corresponding volume of saline. After 20 days of fracture healing, there were no differences in mechanical properties between the healing fractures and intact bones. After 40 days, the ultimate load and maximum stiffness of the fractures of the b-hGH injected animals had increased to more than 400% of the corresponding values of the saline injected animals, and ultimate stress and energy absorption at ultimate load had increased to 270% compared with the saline injected animals. Ultimate load, stiffness, and energy absorption of the intact bones increased in the b-hGH injected animals, but no differences were found in ultimate stress values or normalized energy, indicating that the changes in the intact bones were quantitative phenomena.

The use of serotype 1- and serotype 3-specific polymerase chain reaction for the detection of Marek's disease virus in chickens

A serotype 1- and serotype 3-specific detection of Marek's disease virus (MDV) by polymerase chain reaction (PCR) was developed. The sensitivity of the method when applied to cell culture grown virus was comparable with that of cultivation. The method was applied to various tissue samples from chickens experimentally inoculated with serotype 1 or serotype 3 MDV.The serotype 1 strains CVI988 and RB-1B could be detected in feather follicle epithelium up to 56 and 84 days post-inoculation (p.i.), respectively, while the MDV-3 serotype was detected until 42 days p.i. The purpose of this study was to develop and evaluate a reliable and easy-to-handle method for surveillance of the occurrence of MDV in chicken flocks. We emphasize the development of a method, which can be applied to types of samples conveniently collected in the field, e.g. feather tips and blood samples. In addition, the PCR was applied to samples collected from four commercial table egg layer flocks of young stock or pullets vaccinated with either serotype 1 (CVI988) or serotype 3 (HVT) vaccine. These flocks had various clinical signs of Marek's disease. MDV-1 was detected in buffy-coat cells, spleen, liver, skin, feather tips and ovaries. The detection of MDV in feather tips appeared to be as sensitive as co-cultivation of buffy-coat cells, although an inhibiting factor was observed in extracts from feather tips of non-white chickens. This inhibition could be overcome in most extracts by applying a bovine serum albumen pretreatment. The PCR proved to be a convenient tool for the monitoring of MDV in the poultry population, and feather tips were the most convenient and sensitive samples.

Serum levels of mannan-binding lectin in chickens prior to and during experimental infection with avian infectious bronchitis virus

Mannan-binding lectin (MBL) is a glycoprotein and a member of the C-type lectin super family, the collectin family, and the acute phase protein family. The MBL exerts its function by directly binding to microbial surfaces through its carbohydrate recognition domains, followed by direct opsonization or complement activation via MBL-associated serine proteases (MASP)-1 and -2. Thus, MBL plays a major role in the first-line innate defense against pathogens. We investigated the MBL concentrations in serum during experimental infectious bronchitis virus (IBV) infections in chickens. The results showed that the acute phase MBL response to infection with IBV was, to a degree (P < 0.0068), dependent on whether the chickens were inoculated after 12 h of rest (dark) or after 12 h of activity (light). The acute phase response in chickens challenged after 12 h of activity peaked after 4.6 d with an increase of 24%, whereas the acute phase response in chickens challenged after 12 h of rest peaked after 3.1 d with an increase of 51%. The specific antibody titer against IBV was also tested, and a difference (P < 0.0091) between the two experimental groups was found with peak titer values of 6,816 and 4,349. However, the highest value was found in chickens inoculated after 12 h of activity. Thus, an inverse relation exists between the MBL response and the IBV specific antibody response. The ability of MBL to activate the complement cascade was tested in a heterologous system by deposition of human C4 on the chicken MBL/MASP complex. The complement activation was directly associated with the concentration of MBL in serum, indicating neutralization of the virus before the humoral antibody response took over.

New avian influenza A virus subtype combination H5N7 identified in Danish mallard ducks

During the past years increasing incidences of influenza A zoonosis have made it of uppermost importance to possess methods for rapid and precise identification and characterisation of influenza A viruses. We present here a convenient one-step RT-PCR method that will amplify full-length haemagglutinin (HA) and neuraminidase (NA) directly from clinical samples and from all known subtypes of influenza A. We applied the method on samples collected in September 2003 from a Danish flock of mallards with general health problems and by this a previously undescribed influenza A subtype combination, H5N7, was identified. The HA gene showed great sequence similarity to the highly pathogenic avian influenza A virus (HPAIV) A/Chicken/Italy/312/97 (H5N2); however, the cleavage site sequence between HA1 and HA2 had a motif typical for low pathogenic avian influenza viruses (LPAIV). The full-length NA sequence was most closely related to the HPAIV A/Chicken/Netherlands/01/03 (H7N7) that infected chickens and humans in the Netherlands in 2003. Ten persons with direct or indirect contact with the Danish mallard ducks showed signs of influenza-like illness 2-3 days following the killing of the ducks, but no evidence of influence infections was detected. To our knowledge this is the first report of an H5N7 influenza A virus.

Growth hormone influences collagen deposition and mechanical strength of intact rat skin. A dose-response study

The influence of biosynthetic human growth hormone on biomechanical properties (strain at maximum load, maximum load, relative failure energy, maximum stiffness) and collagen content of intact rat skin was measured after injection of biosynthetic human growth hormone for 90 days at doses of 0.16, 1.10 and 8.33 mg.kg-1.day-1. The mechanical test showed that strain at maximum load, maximum load and relative failure energy increased with increasing doses of biosynthetic hGH. In the group receiving 8.33 mg.kg-1.day-1, skin collagen content per surface area and skin collagen concentration in per cent of dry weight were increased, whereas the fat concentration in per cent of dry weight was decreased. Also when correcting the mechanical data for cross-sectional area, a positive correlation between dose and relative failure energy was found. When dividing the mechanical data by collagen content per surface area of the skin, the maximum stress and relative failure energy reached the highest value at a dose of 1.10 mg.kg-1.day-1. The study shows that biosynthetic hGH can induce an increase in collagen content and mechanical strength of intact rat skin which is dependent on the dose of biosynthetic hGH, and that the increase in mechanical strength cannot be explained only by an increased collagen content.

Treatment of cryptorchidism with human chorionic gonadotropin or gonadotropin releasing hormone. A double-blind controlled study of 243 boys

We have conducted a modified double-blind study on the effect of human chorionic gonadotropin (hCG), gonadotropin releasing hormone (GnRH) and placebo on bilateral and unilateral maldescended testes. One hundred and fifty-five boys with bilateral and 88 boys with unilateral cryptorchidism fulfilled the inclusion criteria and completed the treatment protocol. The boys were between 1 and 13 years of age. hCG was administered as intramuscular injections twice weekly for 3 weeks. GnRH and placebo were given intranasally. hCG was superior to GnRH and placebo in the treatment of bilateral maldescended testes (p = 0.0009). Both testes descended in 25% of the boys following treatment with hCG, and improvement in the position of the testes was obtained in a further 25% of the cases. hCG administration resulted in complete testicular descent in 14% of boys with unilateral cryptorchidism compared with 3 and 0% after placebo and GnRH, respectively (p = 0.07). The testis had moved to a more distal position in 46% of the boys treated with hCG. There was no significant difference between the treatment groups with regard to age or initial position of the testes. We conclude that a success rate of 25% justifies the use of hCG in the treatment of maldescended testes, whereas the study did not support a general use of GnRH administered intranasally.

A dose-response study of the effects of biosynthetic human growth hormone on formation and strength of granulation tissue

The dose-response relationship between biosynthetic human GH (b-hGH) and biomechanical properties (maximum stress, strain at maximum stress, relative failure energy, and maximum stiffness) and collagen deposition of granulation tissue in sc implanted cellulose sponges were investigated after 7 days of implantation in female rats. GH was administered in doses of 0.5, 2.0, and 8.0 mg/kg body weight/day. In the first part of the experiment, treatment with b-hGH started 7 days before implantation of the sponges, in the second part at the day of implantation, and for the 2.0 mg also 2 days before implantation. When b-hGH treatment was started 7 days before implantation, collagen deposition, maximum stress, and maximum stiffness were increased in the sponges from all the hormone-treated groups. In the group treated with 2.0 mg b-hGH/kg body weight.day, also an increase in failure energy was found. When b-hGH treatment was started at the day of implantation or 2 days before implantation, no differences in collagen deposition and biomechanical parameters were found. B-hGH treatment resulted in an increased weight gain in all three groups in the period before implantation, but only 8.0 mg b-hGH/kg body weight resulted in an increased weight gain during the following implantation period. The groups starting hormone treatment at the day of implantation showed an increased weight gain during the implantation period. The study shows that mechanical strength and collagen formation in sc implanted cellulose sponges in rats are increased by b-hGH when treatment is started 7 days before implantation with a maximum increase at a dose of 2.0 mg b-hGH/kg body weight.day.

Serum levels of chicken mannan-binding lectin (MBL) during virus infections; indication that chicken MBL is an acute phase reactant

Mannan-binding lectin (MBL) is a serum collectin which is believed to be an opsonin of the innate immune defence against various microorganisms. MBL is a minor acute phase reactant in man. We investigated the concentration of serum MBL in chickens infected with infectious bronchitis virus (IBV) and infectious laryngotracheitis virus (ILTV). The concentration of serum MBL increased about twofold (from approximately 6 to 12 microg/ml) due to these viral infections. The concentration peaked 3-7 days after infection with IBV, and 3-5 days after ILTV infection, depending on the ILTV strain used. The increased levels returned to normal values 6-10 days after infection. The results indicated that MBL is a minor acute phase reactant in chickens.

Mechanical strength in rat skin incisional wounds treated with fibrin sealant

The biomechanical strength of skin incisional wounds of rats treated with fibrin sealant was assessed by in vitro determination of maximum tensile strength and relative failure energy. Wounds adapted without application of fibrin sealant served as control. Both types of wounds were fixed with surgical tape for the first 8 days of healing. Measurements were performed after 0, 2, 4, 8, 20, and 42 days of healing. After 2 days of healing, wounds treated with fibrin sealant possessed increased maximum tensile strength and relative failure energy. This increase corresponds to the initial strength of the fibrin sealed wounds (0 day values). After 4 and 8 days of healing, no differences were found between the sealed and unsealed groups. After 20 days, the pattern had changed showing increased tensile strength and relative failure energy in wounds not treated with fibrin sealant. A similar trend was reported after 42 days of healing. In both sealed and control wounds, an increase in strain at maximum stress during healing was most pronounced in the first 8 days. After 2 days of healing the strain at maximum stress was increased in wounds treated with fibrin sealant.

Glucocorticoid treatment or food deprivation counteract the stimulating effect of growth hormone on rat cortical bone strength

Growth hormone (GH) has been found to increase the length, thickness and bending strength of rat femora. The present study was designed to investigate if glucocorticoid treatment or food restriction would interfere with the effect of exogenous GH on bone growth. Male rats treated with GH for 30 days experienced a weight gain of 30-35% and longitudinal and periosteal femoral growth. A dose-related increase in the bending strength of the femora was found and was explained by an increased thickness of the femora. In spite of a reduced real density, biomechanical competence was preserved after GH treatment. GH treatment combined with a relatively small dose of glucocorticoid, which in itself had no significant effect on bone growth and strength, reduced the stimulating effect of GH on body weight gain, femoral growth and strength. GH-treated rats that were food restricted, so as to limit their body weight gain to that of the saline group, experienced significant longitudinal and periosteal femoral growth. Bone strength, however, was not increased, which conforms to a reduced mineralization and increased porosity of the femora. Young's modulus (normalized bone stiffness) was significantly decreased in this group, probably as a result of decreased mineralization. Furthermore, the combination of GH treatment and food restriction resulted in a reduced apparent density indicating increased bone resorption.

Dose-response study of the effect of growth hormone on mechanical properties of skin graft wounds

The aim of the study was to investigate the effect of growth hormone on compromised wound healing in a model without exogenously applied metabolic disturbances, e.g., diabetes mellitus. Female Wistar rats were injected with biosynthetic human growth hormone (b-hGH) at 2.0, 4.0, 8.0, and 16.0 mg/kg/day from 7 days before operation to 7 days after. Controls were given saline. On the left side of the dorsal skin a 35 x 20-mm full-thickness skin graft was raised and replaced in situ. After 7 days of healing the wound between the graft and the skin was tested mechanically. The maximum load and maximum stiffness showed a positive correlation with dose of b-hGH, being increased by 40 and 47% in the 8.0 mg group and 34 and 48% in the 16.0 mg group compared with the saline group. During the 7 days of injection before operation serum insulin-like growth factor I (IGF-I) decreased in the saline group, was unchanged in the group given 2.0 and 4.0 mg b-hGH, and was increased in the groups given 8.0 and 16.0 mg b-hGH. Postoperatively, no changes in se-IGF-I were seen in any of the groups when compared to the values at operation. Blood glucose was unaffected by b-hGH treatment. Postoperatively the saline-treated rats showed an 8% weight loss and the 2.0 mg b-hGH group a 3% weight loss, whereas no significant changes were seen postoperatively in the 4.0, 8.0, and 16.0 mg b-hGH groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth hormone promotes healing of tibial fractures in the rat

The effect of administering growth hormone for different periods of time on the mechanical properties of healing rat tibial fractures was investigated after 40 days of healing. Biosynthetic human growth hormone, 2.7 mg/kg body weight/day, was administered to three groups of rats for 1, 2, or 3 weeks following fracture, whereas isotonic saline was administered to a control group for 3 weeks. The ultimate load values and maximum stiffness of the fractures increased in the groups injected with growth hormone for 2 or 3 weeks; linear regression analysis revealed a high probability of a positive linear relationship. In the intact bones an increase in ultimate load, maximum stiffness, and energy absorption at ultimate load was found in the group injected with growth hormone for 3 weeks, with linear regression analysis again showing a high probability of a positive linear relationship.

Major histocompatibility complex-linked immune response of young chickens vaccinated with an attenuated live infectious bursal disease virus vaccine followed by an infection

The influence of the MHC on infectious bursal disease virus (IBDV) vaccine response in chickens was investigated in three different chicken lines containing four different MHC haplotypes. Two MHC haplotypes were present in all three lines with one haplotype (B19) shared between the lines. Line 1 further contains the BW1 haplotype isolated from a Red Jungle Fowl. Line 131 further contains the B131 haplotype isolated from a meat-type chicken. Finally, Line 21 further contains the international B21 haplotype. The chickens were vaccinated with live attenuated commercial IBDV vaccine at 3 wk of age, followed by a challenge with virulent IBDV at 6 wk of age. In this study, we found a notable MHC haplotype effect on the specific antibody response against IBDV, as measured by ELISA. The BW1 haplotype was found to have a significantly higher serum antibody titer against IBDV (7,872) than haplotypes B19 (mean 5,243), B21 (5,570), and B131 (5,333) at 8 d postinfection. However, a virus-neutralizing antibody test did not reflect this result. Nevertheless, the MHC haplotype-associated protective immunity was further supported by the bursa of Fabricius (bursa) recovery from the disease, as measured by histological scorings of the bursa. Chickens carrying the BW1 haplotype had a significantly lower bursa lesion score (1.7) than the haplotypes B19 (mean 3.8), B21 (3.6), and B131 (4.3) 8 d postinfection. Furthermore, multiple line effects were found in other variables when comparing Day 6 with Day 8. Body weight, relative weights of the bursa and the spleen, percentage and relative number of MHC II molecules on MHC II-positive lymphocytes, percentage and relative number of CD4 molecules on CD4-positive lymphocytes, and the specific antibody response all differed significantly among lines. Line 1, with Red Jungle Fowl genes, was clearly differentiated from the other two investigated lines. These results suggest an MHC II restricted T-cell dependent secondary antibody response against IBDV.

Hormonal treatment of cryptorchidism--hCG or GnRH--a multicentre study

In a modified, double-blind controlled study, 163 prepubertal boys (aged 1.8-13.0 years) with bilateral and 94 (aged 1.5-13.1 years) with unilateral cryptorchidism were allocated to treatment with either human chorionic gonadotrophin (im), gonadotrophin releasing hormone (intranasally) or placebo (intranasally). In individuals with the bilateral condition treatment with human chorionic gonadotrophin resulted in complete descent of both testes in 23% of patients. Treatment with human chorionic gonadotrophin in unilateral cryptorchidism resulted in complete descent in 19% of patients; all results were significantly better than those obtained with gonadotrophin releasing hormone or placebo. Linear and logistic regression analysis of the results obtained by treatment of bilateral disease showed that all treatments were more successful the younger the age of the boys. The data indicated that bilateral and unilateral cryptorchidism respond differently to hormonal treatment. We suggest that human chorionic gonadotrophin should be the first choice of treatment for prepubertal boys older than one year.