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1.
Radiography (Lond) ; 29(2): 274-283, 2023 03.
Article in English | MEDLINE | ID: mdl-36621178

ABSTRACT

INTRODUCTION: Global warming and the increase in greenhouse gases are a current concern worldwide. The healthcare sector constitutes about 4.4% of all emissions. This study aims to evaluate the knowledge, awareness and attitudes of Therapeutic Radiographers/Radiation Therapists (TR/RTTs) regarding environment-related concepts to inform the development of educational curriculum. METHODS: A validated self-designed survey was distributed to TR/RTTs across Europe by the SAFE EUROPE partners and via social media between October 2021 and February 2022. The survey was divided into six sections: (i) demographics, (ii) knowledge of Circular Economy (CE) and Green Skills (GS), (iii) personal attitudes, (iv) TR/RTTs attitudes, (v) the importance of CE, and (vi) education. Questions consisted of mostly Likert scales complemented with other closed- and open-ended questions. RESULTS: 31%-42% of participants are aware of national and departmental policies in CE and GS concepts. Even though half of the participants considered that they advocate and practice CE, the open questions indicated that participants only focus on waste management, ignoring all the other dimensions of CE in healthcare. Personal attitudes and lifestyles also did not reflect CE. TR/RTTs considered CE practices and GS development essential. However, the suggested academic level at which these skills should be developed was split between High School (44%) and Bachelor's degree (32%). CONCLUSION: It is essential to raise awareness among TR/RTTs about the various dimensions of CE applied to healthcare: "green transportation", "environment-friendly procurement", "hospital building design", "food process optimisation", "water reduction", "energy efficiency", and "waste management". IMPLICATIONS FOR PRACTICE: These GS must be developed by TR/RTTs to decrease their impact on the environment. Their training may need to be lifelong, starting during basic high school education and continuing as healthcare professionals after graduation.


Subject(s)
Allied Health Personnel , Curriculum , Radiation Oncology , Humans , Health Personnel/education , Surveys and Questionnaires , Radiation Oncology/education
2.
Cancer Radiother ; 26(3): 502-516, 2022 May.
Article in English | MEDLINE | ID: mdl-34772603

ABSTRACT

The aim of the review was to present the current literature status about replanning regarding anatomical and dosimetric changes in the target and OARs in the head and neck region during radiotherapy, to discuss and to analyze factors influencing the decision for adaptive radiotherapy of head and neck cancer patients. Significant progress has been made in head and neck patients' evaluation and qualification for adapted radiotherapy over the past ten years. Many factors leading to anatomical and dosimetric changes during treatment have been identified. Based on the literature, the most common factors triggering re-plan are weight loss, tumor and nodal changes, and parotid glands shrinkage. The fluctuations in dose distribution in the clinical area are significant predictive factors for patients' quality of life and the possibility of recovery. It has been shown that re-planning influence clinical outcomes: local control, disease free survival and overall survival. Regarding literature studies, it seems that adaptive radiotherapy would be the most beneficial for tumors of immense volume or those in the nearest proximity of the OARs. All researchers agree that the timing of re-planning is a crucial challenge, and there are still no clear consensus guidelines for time or criteria of re-planning. Nowadays, thanks to significant technological progress, the decision is mostly made based on observation and supported with IGRT verification. Although further research is still needed, adaptive strategies are evolving and now became the state of the art of modern radiotherapy.


Subject(s)
Head and Neck Neoplasms , Radiotherapy, Image-Guided , Radiotherapy, Intensity-Modulated , Head and Neck Neoplasms/radiotherapy , Humans , Quality of Life , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted
3.
Rep Pract Oncol Radiother ; 25(5): 820-827, 2020.
Article in English | MEDLINE | ID: mdl-32837336

ABSTRACT

The outbreak of SARS-CoV-2 coronavirus rapidly altered radiotherapy service delivery around the world. AIM: The main objective of this study was to assess the impact of precautionary measures implemented in response to the COVID-19 pandemic on the performance of a radiation oncology departments and on mitigation the risk of COVID-19 contagion between and among patients and staff. METHODS: The study period was from March 15 until May 22, 2020. We evaluated total number of patients irradiated and those who initiated treatments, taking into account tumours localisations. We assessed the relationship of potential risk of contagion with patients' domiciles locations in regions with high number of COVID19 case. RESULTS AND CONCLUSIONS: The number of patients treated with radiotherapy during the study period decreased due to precautionary measures. After five weeks, the number of radiotherapy treatments began to increase. Just over half of the radiotherapy patients (53.5%) treated at the GPCC reside in the city of Poznan or in one of the ten surrounding counties where COVID19 incidence was low and reached at the end of the study period cumulative number of cases n = 204. The precautionary measures were effective qRT-PCR tests were performed in 1545 individuals (patients and hospital staff) revealing four staff members and none patient with a positive PCR result. Immunoglobulin testing was performed in 1132 individuals (patients and hospital staff). A total of 63 individuals were positive for antibodies.

4.
Diabetes Res Clin Pract ; 147: 157-165, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30448451

ABSTRACT

AIMS: To confirm non-inferiority of insulin degludec/insulin aspart (IDegAsp) once-daily (OD) versus insulin glargine (IGlar) U100 OD + insulin aspart (IAsp) OD for HbA1c after 26 weeks, and compare efficacy and safety between groups at W26 + W38. METHODS: A 38-week, randomised, open-label, treat-to-target (HbA1c < 7.0%) trial in adults with type 2 diabetes mellitus (on basal insulin ±â€¯oral antidiabetic drugs; HbA1c 7.0-10.0%). Randomisation (1:1): IDegAsp or IGlar U100 + IAsp. Intensification to IDegAsp twice daily (BID) was permitted at W26 + W32, or with additional IAsp injections at W26 (maximum IAsp BID) or W32 (maximum IAsp three-times daily). RESULTS: For W0-W26, mean percentage-change (standard deviation) HbA1c was: IDegAsp, -1.1 (0.9); IGlar U100 + IAsp, -1.1 (0.8); estimated treatment difference: 0.07% (95% confidence interval [CI]: -0.06; 0.21) confirmed non-inferiority. At W26 and W38, target HbA1c achievement, and mean fasting and postprandial glucose were similar across groups. At W38, more subjects achieved target HbA1c without hypoglycaemia with IDegAsp (22.5%) than with IGlar U100 + IAsp (21.1%), with significantly fewer nocturnal episodes (W0-W38, estimated rate ratio: 0.61 [95% CI: 0.40; 0.93]). Safety profiles were similar across treatment groups throughout. CONCLUSIONS: IDegAsp OD/BID are effective treatment intensification options versus multiple injection basal-bolus therapies, achieving similar glycaemic control, with significantly less nocturnal hypoglycaemia.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hypoglycemia/etiology , Hypoglycemic Agents/therapeutic use , Insulin Aspart/therapeutic use , Insulin Glargine/therapeutic use , Diabetes Mellitus, Type 2/pathology , Female , Humans , Hypoglycemia/pathology , Hypoglycemic Agents/pharmacology , Insulin Aspart/pharmacology , Insulin Glargine/pharmacology , Male , Middle Aged
5.
Insectes Soc ; 65(4): 571-580, 2018.
Article in English | MEDLINE | ID: mdl-30416205

ABSTRACT

Glycogen and trehalose are important sources of energy in insects. The expression of genes encoding the key metabolic enzymes-glycogen synthase (GS), glycogen phosphorylase (GP), trehalose-6-phosphate synthase (TPS-1), soluble trehalase (Tre-1) and membrane-bound trehalase (Tre-2)-was analyzed in 12 developmental stages of Apis mellifera worker brood. The content of GS and GP proteins, TPS activity, total trehalase activity, and the activity of Tre-1 and Tre-2 were determined. Transcript quantity was not always correlated with the content of the encoded GS or GP protein. The correlation was higher for GS (r = 0.797) than GP (r = 0.651). The expression of the glycogen synthase gene (gs) and the glycogen phosphorylase gene (gp) was high in 4- and 7-day-old larvae and in pupae, excluding the last pupal stage. The expression of the tps-1 gene was highest in the mid-pupal stage and contributed to higher enzyme activity in that stage. The expression of the tre-1 gene was higher than the expression of the tre-2 gene throughout development. In newly hatched workers, the expression of genes encoding catabolic enzymes of both carbohydrates, gp and tre-1, was higher than the expression of genes encoding anabolic enzymes. The results of this study suggest that sugar metabolism genes have somewhat different control mechanisms during larval development and metamorphosis.

6.
Technol Cancer Res Treat ; 13(3): 233-42, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24066951

ABSTRACT

Helical tomotherapy (HT) was introduced at the Greater Poland Cancer Centre (GPCC) in April 2009. Retrospective analysis included data from the treatments performed for the first 656 patients treated with HT between May 2009 and May 2012 at the GPCC. In order to evaluate the implications on daily workload and scheduling of patients, stepwise regression and time analysis for each component of the overall treatment time, such as positioning, imaging, registration, and irradiation were performed. A detailed analysis included: (1) learning curves and optimized time needed for positioning and registration; (2) relation between irradiation time and parameters used for plan creation; and (3) average time of daily imaging. The irradiation component has the highest influence on the overall treatment time (R = 0.911). The lowest influence was observed for the imaging (R = 0.670). The learning curve for positioning was 7 months while the reduction of the average daily time needed for registration was observed even after two years. The irradiation time strongly depends on the planning parameters. Changing the pitch from 0.215 to 0.287 for pelvic cancer cases decreased the average daily beam-on time per patient by about 2 minutes. Similar changes for head and neck reduced this time by 1.3 minutes. The limitation in the usage of 1 cm field width only for complex cases, lower than 10 cm in the cranio-caudal direction, reduced the beam-on time per patient by 2 minutes. The average overall treatment time decreased from 21.5 minutes per patient in the first year of the HT usage to 13.8 minutes per patient in current practice. Our current practice shows that for a group of patients including mainly those with pelvis and head and neck cancers, the HT treatment takes approximately 15 minutes per patient allowing 40 patients to be treated within 10 hours.


Subject(s)
Appointments and Schedules , Neoplasms/radiotherapy , Radiotherapy, Intensity-Modulated/methods , Time and Motion Studies , Workload , Humans , Personnel Staffing and Scheduling , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Computer-Assisted/methods , Retrospective Studies
7.
J Clin Endocrinol Metab ; 98(12): 4942-52, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24108313

ABSTRACT

CONTEXT: Ig superfamily member 1 (IGSF1) deficiency was recently discovered as a novel X-linked cause of central hypothyroidism (CeH) and macro-orchidism. However, clinical and biochemical data regarding growth, puberty, and metabolic outcome, as well as features of female carriers, are scarce. OBJECTIVE: Our objective was to investigate clinical and biochemical characteristics associated with IGSF1 deficiency in both sexes. METHODS: All patients (n = 42, 24 males) from 10 families examined in the university clinics of Leiden, Amsterdam, Cambridge, and Milan were included in this case series. Detailed clinical data were collected with an identical protocol, and biochemical measurements were performed in a central laboratory. RESULTS: Male patients (age 0-87 years, 17 index cases and 7 from family studies) showed CeH (100%), hypoprolactinemia (n = 16, 67%), and transient partial GH deficiency (n = 3, 13%). Pubertal testosterone production was delayed, as were the growth spurt and pubic hair development. However, testicular growth started at a normal age and attained macro-orchid size in all evaluable adults. Body mass index, percent fat, and waist circumference tended to be elevated. The metabolic syndrome was present in 4 of 5 patients over 55 years of age. Heterozygous female carriers (age 32-80 years) showed CeH in 6 of 18 cases (33%), hypoprolactinemia in 2 (11%), and GH deficiency in none. As in men, body mass index, percent fat, and waist circumference were relatively high, and the metabolic syndrome was present in 3 cases. CONCLUSION: In male patients, the X-linked IGSF1 deficiency syndrome is characterized by CeH, hypoprolactinemia, delayed puberty, macro-orchidism, and increased body weight. A subset of female carriers also exhibits CeH.


Subject(s)
Aging , Congenital Hypothyroidism/physiopathology , Genetic Diseases, X-Linked/physiopathology , Immunoglobulins/deficiency , Membrane Proteins/deficiency , Testicular Diseases/physiopathology , Adult , Aged, 80 and over , Child , Congenital Hypothyroidism/genetics , Congenital Hypothyroidism/immunology , Congenital Hypothyroidism/pathology , Family Health , Female , Genetic Diseases, X-Linked/genetics , Genetic Diseases, X-Linked/immunology , Genetic Diseases, X-Linked/pathology , Heterozygote , Human Growth Hormone/blood , Human Growth Hormone/deficiency , Humans , Immunoglobulins/genetics , Infant , Male , Membrane Proteins/genetics , Metabolic Syndrome/etiology , Organ Size , Prolactin/blood , Puberty, Delayed/etiology , Testicular Diseases/genetics , Testicular Diseases/immunology , Testicular Diseases/pathology , X Chromosome Inactivation
8.
Eur J Radiol ; 39(3): 201-8, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11566250

ABSTRACT

OBJECTIVE: We present preliminary results of a new method (hereinafter called 'CT-clearance') to measure single kidney contrast media clearance by performing multiphasic helical CT of the kidneys. CT-clearance was calculated according to an extension of the Patlak-Plot. In contrast to prior investigators, who repeatedly measured a single slice, this method makes it possible to calculate single kidney clearance from at least three spiral CTs, utilizing the whole kidney volume. METHODS: Spiral CT of the kidneys was performed unenhanced and about 30 and 100 s after administration of about 120 ml iopromide. Sum-density of the whole kidneys and aortic density was calculated from this data. Using this data, renal clearance of contrast media was calculated by CT-clearance in 29 patients. As reference, Serum-clearance was calculated in 24 patients by application of a modified one-exponential slope model. Information on the relative kidney function was gained by renal scintigraphy with Tc99m-MAG-3 or Tc99m-DMSA in 29 patients. RESULTS: Linear regression analysis revealed a correlation coefficient of CT-clearance with Serum-clearance of r=0.78 with Cl (CT) [ml/min]=22.2+1.03 * Cl (serum), n=24. Linear regression of the relative kidney function (rkf) of the right kidney calculated by CT-clearance compared to scintigraphy results provided a correlation coefficient r=0.89 with rkf(CT)[%]=18.6+0.58 * rkf(scintigraphy), n=29. CONCLUSION: The obtained results of contrast media clearance measured by CT-clearance are in the physiological range of the parameter. Future studies should be performed to improve the methodology with the aim of higher accuracy. More specifically, better determination of the aortic density curve might improve the accuracy.


Subject(s)
Contrast Media/pharmacokinetics , Iohexol/pharmacokinetics , Kidney/diagnostic imaging , Tomography, X-Ray Computed/methods , Humans , Iohexol/analogs & derivatives , Kidney/physiology , Linear Models , Radioisotope Renography , Technetium Tc 99m Dimercaptosuccinic Acid , Technetium Tc 99m Mertiatide
10.
J Bone Miner Res ; 8(9): 1097-101, 1993 Sep.
Article in English | MEDLINE | ID: mdl-8237479

ABSTRACT

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.


Subject(s)
Bone and Bones/drug effects , Femur/drug effects , Parathyroid Hormone/pharmacology , Peptide Fragments/pharmacology , Animals , Biomechanical Phenomena , Body Weight/drug effects , Bone and Bones/physiology , Femur/physiology , Humans , Male , Random Allocation , Rats , Rats, Wistar , Recombinant Proteins/pharmacology , Teriparatide
11.
Acta Orthop Scand ; 64(1): 59-63, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8451949

ABSTRACT

We investigated the effect of local infusion with prostaglandin E2 (PGE2) in doses of 0.0003 to 4.0 mg/hour per kg body weight for 6 weeks on a plated unilateral osteotomy in rabbits. PGE2 caused a dose-dependent stimulation of callus formation. Total bone mineral content increased, although the mineral content per volume of the callus was reduced. In another experiment, PGE2 was infused either in the first half or in the second half of the healing period. No effect of PGE2 infusion could be observed in the first half of the 6-week healing period, whereas PGE2 infusion during the second half caused callus stimulation.


Subject(s)
Bony Callus/drug effects , Dinoprostone/pharmacology , Fracture Healing/drug effects , Fractures, Bone/surgery , Animals , Biomechanical Phenomena , Bone Density/drug effects , Bone Plates , Compliance , Dose-Response Relationship, Drug , Fracture Healing/physiology , Fractures, Bone/physiopathology , Osteotomy , Rabbits , Tibia/chemistry , Tibia/drug effects , Tibia/surgery
12.
Bone ; 14(1): 19-27, 1993.
Article in English | MEDLINE | ID: mdl-8442998

ABSTRACT

Previous biomechanical studies have indicated that growth hormone has a stimulatory effect on fracture healing. This study was designed to give a histological description of the long-term effects of growth hormone on fracture healing in rats. Sixty-four female rats were divided into two groups and were given either biosynthetic human growth hormone (2.7 mg/kg body weight/day) or saline s.c. in two daily injections. This treatment was given for 20 days after a closed tibial fracture with medullary nailing had been performed. Five or six rats were killed from each group after 10, 20, 30, 40, 50, and 80 days of healing. The fracture site was embedded undecalcified in methylmethacrylate, cut into 8 microns thick, mid-frontal sections, and investigated in a normal light microscope after staining with Masson Trichrome and in polarized light after staining with Sirius red. The results revealed that growth hormone had an initially stimulatory effect on external callus formation. However, the callus formed was loosely structured and was not removed by the normal modeling and remodeling process. The callus therefore persisted even after 80 days of healing. In contrast, after only 40 days the saline treated rats showed healing, with a resumption of the normal size and shape of the fractured tibial bone, leaving only a small amount of dense callus tissue. The study also revealed that the hemopoietic system was stimulated by growth hormone, with massive invasion of marrow cells into the external fracture callus. Bone marrow cells dominated the intratrabecular space in growth-hormone treated animals, even after 80 days of healing.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Fracture Healing/drug effects , Growth Hormone/pharmacology , Animals , Bone Marrow/drug effects , Bone Marrow/pathology , Bone Remodeling/drug effects , Bony Callus/drug effects , Bony Callus/growth & development , Female , Fractures, Bone/drug therapy , Fractures, Bone/pathology , Rats , Rats, Wistar , Time Factors
13.
Bone ; 13(4): 289-95, 1992.
Article in English | MEDLINE | ID: mdl-1389568

ABSTRACT

The influence of the fracture level on the biomechanical properties of healing rat tibial fractures has not been investigated so far, despite the widespread use of rats in fracture healing studies. Fractures were produced in four different zones in the right rat tibia and immobilized with a K-wire. A fifth group of rats was not fractured. After 40 days of healing the fractures and the non-fractured bones were tested in three-point bending. A distinct correlation was found between fracture level and mechanical parameters: maximum load, maximum stiffness, and maximum stress decreased the more distal the fracture was located. In the non-fractured bones, maximum load and maximum stress were constant in all four zones tested, whereas energy absorption increased in the distal part of the tibia. No influence of the healing fracture was found on the contralateral, non-fractured tibia, compared with the animals left undisturbed, and the mechanical properties of the right and the left tibia were found to be symmetrical in terms of mean values. Four different methods of determining the area moment of inertia were investigated, and the simple method of approximating the cross section to an elliptical annulus was found to correlate well with the area moment of inertia, determined from computer tracings of bone slices prepared from the test specimens after the bending test. The computer tracings were corrected for the compression of the specimens caused by the mechanical test.


Subject(s)
Fracture Healing/physiology , Tibial Fractures/physiopathology , Animals , Biomechanical Phenomena , Bone and Bones/physiology , Female , Rats , Rats, Wistar , Reference Standards , Reproducibility of Results
14.
Carcinogenesis ; 12(10): 1795-800, 1991 Oct.
Article in English | MEDLINE | ID: mdl-1934259

ABSTRACT

O6-Methylguanine-DNA methyltransferase (O6-MT) is a DNA repair protein that reverses alkylation damage at the O6 position of guanine. In the process, O6-MT undergoes suicide inactivation. To determine if this enzyme might be regulated by pregnancy-associated hormones we measured changes in the level of O6-MT in isolated mouse mammary epithelial cell homogenates during different reproductive states. These were pregnancy, ectopic pituitary transplantation, proestrus/estrus and diestrus. O6-MT levels were found to be similar in mice in proestrus/estrus (0.95 fmol/micrograms DNA) as compared to diestrus (0.94 fmol/micrograms DNA) and also mixed populations of virgin mice (1.09 fmol/micrograms DNA). A mean for all virgin mice (0.97 fmol/micrograms DNA) was used as a comparative index. O6-MT decreased 2-fold during pregnancy in mammary epithelial cells to a mean value of 0.45 fmol/micrograms DNA (P less than 0.05). A smaller decrease (0.65 fmol/micrograms DNA; P less than 0.01) in mammary epithelial cells was found at 3 weeks following pituitary isograft. The repair capacity of mammary epithelial cells to liver was compared by measurements made in liver homogenates from the same mice and are approximately 3-fold higher in liver from virgin mice (3.2 fmol/micrograms DNA) than mammary gland. Liver levels of O6-MT increased in pregnant (5.3 fmol/micrograms DNA) and pituitary transplanted (3.9 fmol/micrograms DNA) mice, and were 5- and 4-fold higher than the concentration in virgin mammary epithelial cells respectively.


Subject(s)
Liver/enzymology , Mammary Glands, Animal/enzymology , Methyltransferases/metabolism , Pregnancy, Animal/metabolism , Animals , Colonic Neoplasms/enzymology , Colonic Neoplasms/pathology , Epithelial Cells , Epithelium/enzymology , Estrus/metabolism , Female , Liver/cytology , Mice , Mice, Inbred BALB C , O(6)-Methylguanine-DNA Methyltransferase , Pituitary Gland/physiology , Pituitary Gland/transplantation , Pregnancy , Tumor Cells, Cultured/enzymology
15.
Acta Orthop Scand ; 62(3): 244-7, 1991 Jun.
Article in English | MEDLINE | ID: mdl-2042466

ABSTRACT

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.


Subject(s)
Growth Hormone/pharmacology , Tibial Fractures/therapy , Wound Healing/drug effects , Animals , Female , Growth Hormone/administration & dosage , Rats , Rats, Inbred Strains , Regression Analysis , Time Factors
16.
Clin Orthop Relat Res ; (264): 295-301, 1991 Mar.
Article in English | MEDLINE | ID: mdl-1997248

ABSTRACT

The effect of onset and duration of growth hormone administration on the biomechanical 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 given in two daily injections to three groups of rats: (1) for the entire healing period; (2) for the first 20 days; and (3) for the last 20 days of healing. Three corresponding groups of control rats were injected with saline. In Group 1, maximum load and stiffness of the healing fractures increased to 165% and 175%, respectively, compared to the control group. In Group 2, maximum load, stiffness, maximum stress, and energy absorption at maximum load increased to 222%, 175%, 171%, and 247%, respectively, compared to the control group. In Group 3, no statistically detectable effects were found. The results show that growth hormone stimulates fracture healing both when given during the first part of the healing period and when given during the entire healing period.


Subject(s)
Bone Development/drug effects , Fractures, Bone/physiopathology , Growth Hormone/administration & dosage , Animals , Biomechanical Phenomena , Body Weight/physiology , Female , Fractures, Bone/drug therapy , Growth Hormone/pharmacology , Growth Hormone/therapeutic use , Rats , Rats, Inbred Strains , Tibial Fractures/drug therapy , Tibial Fractures/physiopathology , Time Factors , Wound Healing/physiology
17.
Bone ; 12(3): 151-4, 1991.
Article in English | MEDLINE | ID: mdl-1910956

ABSTRACT

The healing of fractures is known to decrease with age. Several mechanisms have been identified that might explain this age-related decrease in capacity for fracture repair, one of them being a decrease in growth hormone secretion. In the present experiment, two-year-old male rats with a standardized tibial fracture were given biosynthetic human growth hormone (b-hGH, 2.7 mg/kg/day in two daily injections) during the first 40 days of fracture healing and the controls were injected with saline. After 40 or 80 days of healing, the mechanical properties of the healing fractures were evaluated by three-point bending. At day 40, no differences were found in mechanical properties of fractured and intact tibiae between b-hGH injected rats and saline injected controls. At day 80, ultimate load, stiffness, and ultimate stress of the fractures had increased by 78%, 63%, and 58%, respectively, compared with the controls. In the contralateral, intact tibiae, ultimate load and energy absorption had increased by 12% and 17%, respectively, compared with the controls.


Subject(s)
Fractures, Bone/drug therapy , Growth Hormone/pharmacology , Animals , Biomechanical Phenomena , Fractures, Bone/physiopathology , Male , Rats , Rats, Inbred Strains , Time Factors , Wound Healing/drug effects
18.
Bone ; 12(5): 353-9, 1991.
Article in English | MEDLINE | ID: mdl-1782103

ABSTRACT

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.


Subject(s)
Femur/drug effects , Growth Hormone/pharmacology , Tibia/drug effects , Analysis of Variance , Animals , Biomechanical Phenomena , Bone Density/drug effects , Collagen/metabolism , Female , Femur/metabolism , Femur/physiology , Humans , Random Allocation , Rats , Rats, Inbred Strains , Tibia/metabolism , Tibia/physiology , Time Factors
19.
Acta Orthop Scand ; 61(1): 54-7, 1990 Feb.
Article in English | MEDLINE | ID: mdl-2336953

ABSTRACT

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.


Subject(s)
Fractures, Bone/physiopathology , Growth Hormone/pharmacology , Animals , Biomechanical Phenomena , Dose-Response Relationship, Drug , Elasticity , Female , Rats , Rats, Inbred Strains , Wound Healing/drug effects
20.
Bone ; 11(4): 233-9, 1990.
Article in English | MEDLINE | ID: mdl-2242289

ABSTRACT

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.


Subject(s)
Fractures, Closed/drug therapy , Growth Hormone/therapeutic use , Tibial Fractures/drug therapy , Animals , Biomechanical Phenomena , Female , Humans , Random Allocation , Rats , Rats, Inbred Strains , Recombinant Proteins/therapeutic use , Wound Healing/drug effects
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