Hyperbaric oxygen therapy improves colorectal anastomotic healing.

PURPOSE: Hyperbaric oxygen treatment (HBOT) has been found to improve the healing of poorly oxygenated tissues. This study aimed to investigate the influence of HBOT on the healing in ischemic colorectal anastomosis. METHODS: Forty Wistar rats were randomly divided into a treatment group that received HBOT for 10 consecutive days (7 days before and 3 days after surgery), or in a control group, which did not receive the therapy. Colectomy with an ischemic anastomosis was performed in all rats. In each group, the rats were followed for 3 or 7 days after surgery to determine the influence of HBOT on anastomotic healing. RESULTS: Five rats from each group died during follow-up. No anastomotic dehiscence was seen in the HBOT group, compared to 37.5 % and 28.6 % dehiscence in the control group on postoperative day (POD) 3 and 7, respectively. The HBOT group had a significantly higher bursting pressure (130.9 ± 17.0 mmHg) than the control group (88.4 ± 46.7 mmHg; p = 0.03) on POD 3. On POD 3 and POD 7, the adhesion severity was significantly higher in the control groups than in the HBOT groups (p < 0.005). Kidney function (creatinine level) of the HBOT group was significantly better than of the control group on POD 7 (p = 0.001). Interestingly, a significantly higher number of CD206+ cells (marker for type 2 macrophages) was observed in the HBOT group at the anastomotic area on POD 3. CONCLUSION: Hyperbaric oxygen enhanced the healing of ischemic anastomoses in rats and improved the postoperative kidney function.

The incidence of symptomatic neuroma in amputation and neurorrhaphy patients.

PURPOSE: The incidence of symptomatic neuroma in finger nerve injuries varies widely in the literature. In this retrospective study, we evaluated the incidence of symptomatic neuroma after repair of digital nerve injuries (neurorrhaphy) and after amputation of one or more fingers. We also determined the need for re-operation on symptomatic neuroma patients. METHODS: In a retrospective study, we collected data from medical files. All patients who were treated for a hand trauma in the emergency department during the last 10 years were included. We gathered data on the presence of symptomatic neuroma and re-operation of the patients. RESULTS: In our database, 583 people had a peripheral nerve injury of whom 177 people had an amputation. The incidence of digital nerve injury without amputation followed by neurorrhaphy was 1%. In digital nerve injuries with amputation the incidence was 7.8%, which is significantly higher than after digital nerve injuries without amputation. CONCLUSIONS: People with an amputation injury have significantly more symptomatic neuroma than people who undergo neurorrhaphy. People who have a symptomatic neuroma after digital nerve injuries have been operated significantly more than people who have a non-symptomatic neuroma or no neuroma at all. This information can be of help when treating digital nerve injuries. TYPE OF STUDY/LEVEL OF EVIDENCE (LOE): Prognostic.

Tissue-engineered mucosa is a suitable model to quantify the acute biological effects of ionizing radiation.

The aim of this study was to evaluate the suitability of tissue-engineered mucosa (TEM) as a model for studying the acute effects of ionizing radiation (IR) on the oral mucosa. TEM and native non-keratinizing oral mucosa (NNOM) were exposed to a single dose of 16.5Gy and harvested at 1, 6, 24, 48, and 72h post-irradiation. DNA damage induced by IR was determined using p53 binding protein 1 (53BP1), and DNA repair was determined using Rad51. Various components of the epithelial layer, basement membrane, and underlying connective tissue were analyzed using immunohistochemistry. The expression of cytokines interleukin-1ß (IL-1ß) and transforming growth factor beta 1 (TGF-ß1) was analyzed using an enzyme-linked immunosorbent assay. The expression of DNA damage protein 53BP1 and repair protein Rad51 were increased post-irradiation. The expression of keratin 19, vimentin, collage type IV, desmoglein 3, and integrins α6 and ß4 was altered post-irradiation. Proliferation significantly decreased at 24, 48, and 72h post-irradiation in both NNOM and TEM. IR increased the secretion of IL-1ß, whereas TGF-ß1 secretion was not altered. All observed IR-induced alterations in TEM were also observed in NNOM. Based on the similar response of TEM and NNOM to IR we consider our TEM construct a suitable model to quantify the acute biological effects of IR.

Changes of mandibular ramal height, during growth in unilateral hemifacial microsomia patients and unaffected controls.

The aim of this study was to design mandibular ramal height growth curves for patients with HFM and compare those with the curves for a Dutch reference population. Two hundred fifty-one pre-operative orthopantomograms (OPTs) from 84 patients with unilateral HFM were used in conjunction with a control set of 2260 OPTs from 329 healthy individuals from the Nijmegen Growth Study (NGS) to determine mandibular ramal distances. For grades I/IIa and IIb/III, and for both sides, growth curves were constructed for mandibular ramal height with a linear curve-fitting procedure. This procedure revealed a significant difference between HFM patients and the NGS control group (p < 0.001); both in the mild and severe group mandibular ramal height differed significantly between the affected and non-affected side (p < 0.001). Growth was similar between HFM patients and the NGS control group. HFM patients therefore start with a smaller mandible and end with a smaller mandible, but experience growth similar to the Dutch normal population. These growth curves may aid the timing and determination of the combined surgical orthodontic treatment plan for HFM patients.

Craniofacial morphology in unilateral hemifacial microsomia.

Hemifacial microsomia (HFM) is a complex three-dimensional congenital condition that is characterized by mandibular hypoplasia and unilateral or bilateral microtia; although, other facial structures may be affected. Little is known about craniofacial growth and morphology in patients with HFM; therefore, we examined 75 HFM patients by means of a cephalometric analysis in a longitudinal study on serial lateral cephalograms. We hypothesized that the growth of several facial structures on both sides of HFM patients would be different compared to Dutch controls. We determined patients with HFM had more retruded mandibles and maxillae and a more vertical morphology compared to the reference population. In addition, there was a more retruded and vertical pattern on the affected side compared to the unaffected side and in patients with a severe condition compared to those with a mild condition. 'Mild' HFM patients were more similar to the Dutch reference population than the 'severe' HFM patients. Individual HFM growth curves showed very high inter-variability, further strengthening the need for individualized treatment plans that consider all three dimensions and the severity of the condition.

High-resolution ultrasonography of the cutaneous nerve branches in the hand and wrist.

Ultrasonography can be used in the diagnosis of various neuropathies, including nerve injury. Nerves often involved in traumatic and iatrogenic injury are small cutaneous branches in the hand and wrist, which cannot be seen in detail using current ultrasound probes. This study explored the potential of high-resolution ultrasonography in seeing these nerve branches in the human. The VisualSonics Vevo 770 system with a 15-82.5 MHz probe was compared to a commonly used 5-12 MHz probe and ultrasound machine. The accuracy was validated by ultrasound guided dye injection into cadaver nerves, with subsequent anatomical dissection and verification. Results were confirmed in two healthy volunteers. The Vevo 770 system was able to accurately identify the small cutaneous nerves. It could also depict the median nerve and its fascicles in greater detail. This may be useful for clinical diagnosis, localisation and follow-up of neuropathies and nerve injuries.

Histomorphometric comparison between continuous and discontinuous distraction osteogenesis.

INTRODUCTION: Experimental research on optimising the distraction protocol has been performed extensively in the past. However, relatively little research has been done on the rhythm of distraction. Findings in the orthopaedic literature showed that the outcome of distraction osteogenesis (DO) is positively influenced by increasing the rhythm of distraction. The aim of this study is to quantitatively compare continuous with discontinuous rhythms of distraction in rabbits. MATERIALS AND METHODS: Tissue blocks of regenerated bone were harvested from thirty-eight young adult female New-Zealand White rabbits. After a latency period of three days, rabbits were subjected for eleven days to either single daily activation of the distractor at a rate of 0.9 mm/d, or triple daily activation at a rate of 0.9 mm/d, or continuous activation at a rate of 0.9 mm/d. After three weeks of consolidation, bone regenerates were analysed using histomorphometry. RESULTS: The continuous DO group showed significantly (p<.01) more regenerate bone volume in the central part of the regenerate than the discontinuous DO groups. Higher osteoblastic activity was seen, as well as more blood vessels (p<.05). Bone volume and the number of blood vessels correlated significantly in the central part of the regenerate (p<.05). Also, the early mineral apposition rate (MAR) was higher than the late MAR (p<.05). CONCLUSIONS: Continuous DO significantly accelerates bone formation when compared with discontinuous DO.

Linear mandibular measurements: comparison between orthopantomograms and lateral cephalograms.

OBJECTIVE: To investigate the reliability of length measurements of the mandible by comparing orthopantomograms (OPTs) with lateral cephalograms. DESIGN: Observational study. SETTING: OPTs and lateral cephalograms were taken of 20 human dry skulls. Four orthodontists and four maxillofacial surgeons located landmarks on all radiographs using a computer program for cephalometric measurements. Intraobserver and interobserver variability in locating landmarks was assessed, as well as positioning of the skulls prior to radiography between the x-ray assistants. Magnification differences between the left and right side of the mandible on the OPT were determined for five skulls. Kappa statistics were used to calculate the intraclass correlation coefficient for intraobserver and interobserver differences. An F test was used to assess differences between methods and between type of observer. RESULTS: No significant differences were found in the magnification factor of the left and right side of the mandible. Compared with a lateral cephalogram, the OPT had comparable reliability in measuring mandibular distances condylion-gonion, gonion-menton, and condylion-menton. No significant differences were observed between the x-ray assistants in taking the OPTs and lateral cephalograms or in repositioning the skulls. Significant differences were found between orthodontists and maxillofacial surgeons for landmark measurements. CONCLUSION: An OPT is as reliable as a lateral cephalogram for linear measurements of the mandible (condylion-gonion, gonion-menton, and condylion-menton).

Rabbits as a model for research into craniofacial distraction osteogenesis.

Various factors affect the choice of the appropriate animal for craniofacial research. We have evaluated the rabbit as a suitable animal for research on craniofacial distraction osteogenesis. We describe our experience with housing and handling them, surgical and experimental protocols, and compare them with other animals. We introduce, and describe the use of, a continuous hydraulic distractor on the nasal bones of the rabbit. Fifty-two skeletally mature New Zealand White rabbits were used. Forty-two of the 52 operations were uneventful. Ten of the fifty-two developed complications, of which two were animal-related, and the other eight distractor-related. During the experiments the animals stayed healthy, and the distraction procedures were well tolerated. Rabbits are excellent for use in biological research on craniofacial distraction osteogenesis. Specifically, their nasal bones are easily accessible, the size and shape of the nasal bones allow various commercially available as well as custom-made distractors to be attached to the bones easily, their care and housing are relatively simple and inexpensive, and harvesting of tissue for further analyses is no problem because their skulls are of a manageable size and shape compared with other laboratory animals.

Recommendations for optimal distraction protocols for various animal models on the basis of a systematic review of the literature.

The principles of orthopaedic distraction osteogenesis (DO) have been successfully applied to the craniofacial skeleton, but the latency time, rate and rhythm of distraction, and length of the consolidation period that are optimal for long-bone distraction may be suboptimal for craniofacial DO. The aim of this study was to provide recommendations for optimal distraction parameters in animal experimental research on craniofacial DO. The data used were from studies, added to the PubMed database between 1 January 1973 and 1 January 2007, on the outcome of DO resulting from variations in a single distraction parameter while standardizing the other distraction parameters. Although experimental animal group sizes were rather small, especially in those studies that used large animals, and both skeletally mature and immature animals were used, the (in most cases quantitative) data provided useful information on the optimal parameters in craniofacial DO. A latency period may not be necessary at all. Distraction should be performed at a rate of 1mm/day (this may be halved when small animals such as rats are used) preferably with a continuous rhythm, followed by a consolidation period of 6-8 weeks. These recommendations can be used as basic guidelines for further animal experimental studies on craniofacial DO.

Mucosal keratinocyte isolation: a short comparative study on thermolysin and dispase.

New techniques for reconstructing large defects of the floor of the mouth include the use of cultured mucosal substitutes. The purpose of this study was to compare dispase and thermolysin for keratinocyte isolation. Keratinocyte yield per surface area of rabbit buccal mucosa was assessed by histology, cytokeratin 13 (CK13) staining, seeding efficiency analysis and cell diameter quantification. Surface areas of cultured mucosa were calculated. Histology showed that treatment by thermolysin resulted in incomplete separation of epidermis from dermis. Also, the absolute number of keratinocytes/cm(2) isolated mucosa, cell yield, cell size and seeding efficiencies was higher in the dispase group. A 3.45-fold larger graft could be reconstituted using dispase. The use of dispase, rather than thermolysin, to isolate cells from buccal mucosa is concluded to be favourable.

Serial noninvasive photoacoustic imaging of neovascularization in tumor angiogenesis.

We present photoacoustic images of tumor neovascularization obtained over a 10-day period after subcutaneous inoculation of pancreatic tumor cells in a rat. The images were obtained from ultrasound generated by absorption in hemoglobin of short laser pulses at a wavelength of 1064 nm. The ultrasound signals were measured in reflection mode using a single scanning piezodetector, and images were reconstructed with a weighted delay-and-sum algorithm. Three-dimensional data visualize the development and quantify the extent of individual blood vessels around the growing tumor, blood concentration changes inside the tumor and growth in depth of the neovascularized region.

Gene expression of the insulin-like growth factor system during postnatal development of the rat pituitary gland.

Insulin-like growth factors I and II (IGFI and II) are synthesized by anterior pituitary cells and participate in cellular growth and differentiation, as well as the control of pituitary hormone secretion. Type 1 and 2 IGF receptors (IGFR1 and IGFR2) and the six IGF binding proteins (IGFBPs), which modulate IGF effects, are expressed in the anterior pituitary gland. We used in situ hybridization to analyse the temporal expression pattern of IGFI and II, IGFR1 and 2 and IGFBP1-6 in the anterior pituitary gland during postnatal development in both male and female rats (10, 20, 30, 40 and 60 days of age). We found all of the components of the IGF system to be expressed in the anterior pituitary gland, with each having a specific temporal pattern of expression. In addition, there exist differences between the sexes in the expression of some components of the IGF system. These data emphasize that in the anterior pituitary gland the IGF system is under tight regulation during postnatal life when this gland continues to develop. The distinct temporal expression of each member of the IGF system may indicate specific roles in the development and physiology of the anterior pituitary gland.

Generation of antisera to mouse insulin-like growth factor binding proteins (IGFBP)-1 to -6: comparison of IGFBP protein and messenger ribonucleic acid localization in the mouse embryo.

The insulin-like growth factor (IGF) system is an important regulator of fetal growth and differentiation. IGF bioavailability is modulated by IGF binding proteins (IGFBPs). We have generated six different antisera, directed to synthetic peptide fragments of mouse IGFBP-1 through -6. The specificity of the produced antisera was demonstrated by enzyme-linked immunosorbent assay, Western blotting, and by immunohistochemistry on sections of mouse embryos of 13.5 days post coitum. Specificity for the IGFBP-2 through -6 antisera also was confirmed immunohistochemically in liver and lung of corresponding gene deletion (knock-out) mutant mice and wild-type litter mates. Immunohistochemistry and messenger RNA (mRNA) in situ hybridization on sections of mouse embryos of 13.5 days post coitum revealed tissue-specific expression patterns for the six IGFBPs. The only site of IGFBP-1 protein and mRNA production was the liver. IGFBP-2, -4, and -5 protein and mRNA were detected in various organs and tissues. IGFBP-3 and -6 protein and mRNA levels were low. In several tissues, such as lung, liver, kidney, and tongue, more than one IGFBP (protein and mRNA) could be detected. Differences between mRNA and protein localization were extensive for IGFBP-3, -5, and -6, suggesting that these IGFBPs are secreted and transported. These results confirm the different spatial localization of the IGFBPs, on the mRNA and protein level. The overlapping mRNA and protein localization for IGFBP-2 and -4, on the other hand, may indicate that these IGFBPs also function in an auto- or paracrine manner.

The role of progestins, insulin-like growth factor (IGF) and IGF-binding proteins in the normal and neoplastic mammary gland of the bitch: a review.

The growth hormone (GH) and insulin-like growth factor (IGF) system is an important regulatory system of mammalian epithelial cell proliferation and differentiation. The biological effects of the IGFs are modulated by six different binding proteins (IGFBPs). Progestins play an important role in the regulation of the dynamics of mammary gland development and involution through the modulation of these growth regulating factors. In dogs and cats, progestins stimulate the local production of GH in the mammary gland. In dogs, this results in high plasma concentrations of GH and a concomitant increase in plasma IGF-I and IGFBP-3 concentrations. The administration of progestins also induces high plasma concentrations of IGF-II, even before GH concentrations start to increase. In the mammary gland of the normal bitch, IGFBP-5 and IGFBP-2 are the main IGFBPs expressed. Progestin administration results in a decrease of mRNA encoding IGFBP-5, but does not alter the concentration of mRNA encoding IGFBP-2. This local mammary system of GH, IGFs and IGFBPs plays an important role in the regulation of mammogenesis, lactation and involution. However, the presence of a high proliferative environment may also enhance the risk of malignant transformation and promotion of tumour growth with an associated inhibition of programmed cell death.

Stimulation of hepatic insulin-like growth factor-binding protein-1 and -3 gene expression by octreotide in rats.

It has recently been demonstrated in various clinical experiments that native somatostatin and its long-acting analogues increase circulating levels of insulin-like growth factor-binding protein-1 (IGFBP-1) within 1-2 h, independent of effects on circulating insulin or glucose levels. Using human hepatoma cells in vitro the somatostatin analogue, octreotide, has been shown to increase IGFBP-1 mRNA within 24 h indicative of a direct stimulatory effect of octreotide on IGFBP-1 synthesis. In order to ascertain whether octreotide acutely stimulates IGFBP-1 mRNA in vivo, placebo or two doses of octreotide were injected subcutaneously into three groups of rats. One hour after saline or octreotide administration, liver, kidney and serum were obtained for the measurement of IGFBPs-1 to -6 mRNA in tissue and IGFBPs and IGF-I in serum. Octreotide increased liver IGFBP-1 (562%) and IGFBP-3 (23%) mRNA expression with a concomitant rise in the circulating 30 kDa (106%) and 38-42 kDa (23%) IGFBPs. No detectable changes were seen in other liver IGFBP transcripts, other circulating IGFBPs or in any of the kidney IGFBP transcripts. Serum IGF-I increased by 37% in the animals receiving the high octreotide dose. No concomitant changes were observed in glucose or insulin levels. These data show that octreotide acutely stimulates hepatic IGFBP-1 and -3 mRNA in vivo in rats. The stimulating effect on IGFBP-3 presents a possible hitherto unknown form of regulation of IGFBP-3 whilst the effect on IGFBP-1 indicates that the stimulatory effect of octreotide on circulating IGFBP-1 described in clinical trials may be due to increased hepatic production. The present findings may be of importance in the clinical use of octreotide.

Proliferation of the murine corticotropic tumour cell line AtT20 is affected by hypophysiotrophic hormones, growth factors and glucocorticoids.

In pituitary-dependent hyperadrenocorticism (Cushing's disease), the disturbed regulation of ACTH secretion is associated with neoplastic transformation of corticotropic cells. As these two phenomena are almost indissolubly connected, it is of prime importance to elucidate the factor(s) that induce corticotropic cell proliferation. Here we report on the effects of hypophysiotrophic hormones and intrapituitary growth factors on the proliferation and hormone secretion of the murine corticotropic tumour cell line AtT20/D16v, as measured by DNA content, and ACTH concentration in culture media. In addition, sensitivity to the inhibitory effect of cortisol was assessed under various conditions. Corticotropin releasing hormone (CRH) and vasopressin (AVP) induced proliferation of AtT20-cells. In contrast to that caused by AVP, the CRH-induced proliferation was associated with increased ACTH secretion, which could be inhibited by cortisol. Insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) also stimulated the proliferation of AtT20-cells. The proliferation of AtT20-cells was significantly inhibited by cortisol in all tests. The IGF-I-induced proliferation was the least sensitive to inhibition by cortisol. The growth factors did not stimulate ACTH secretion but IGF-I differed in that it prevented the inhibition of basal ACTH secretion by cortisol. Additional experiments (Western ligand blot analysis) concerning the relative insensitivity of IGF-I induced proliferation to inhibition by cortisol revealed that IGF-I increased the concentration of a 29 kDa IGF binding protein (IGFBP) in the culture medium. The concentration of the 29 kDa IGFBP was slightly decreased by cortisol.(ABSTRACT TRUNCATED AT 250 WORDS)

Basic fibroblast growth factor has a differential effect on MyoD conversion of cultured aortic smooth muscle cells from newborn and adult rats.

MyoD is a master regulatory gene for myogenesis that also converts many mesoderm-derived cells into the skeletal muscle phenotype. Rat aortic smooth muscle cells do not contain MyoD homologous mRNA. However, expression of an exogenously supplied MyoD gene in aortic smooth muscle cells cultured from newborn and adult animals converts these cells to elongated myoblasts and myotubes expressing the skeletal muscle genes for titin, nebulin, myosin, and skeletal alpha-actin. The presence of basic fibroblast growth factor during growth and serum starvation completely inhibits MyoD-mediated conversion in cultures of newborn smooth muscle cells. However, in smooth muscle cell cultures derived from adult rats the presence of fibroblast growth factor increases the conversion frequency. The differential response of exogenous MyoD suggests that the two morphological types of aortic smooth muscle cells, one typical for the newborn rat, the other for the adult rat, represent two distinctive states of differentiation.

Effect of ploidy on transcription levels in cultured rat aortic smooth muscle cells.

Aging and hypertension increase the number of polyploid smooth muscle cells (SMC) in a blood vessel. We assessed the effect of ploidy on the transcription of several genes in SMC cultures derived from newborn and adult rats. In diploid and tetraploid subcultures of SMC from newborn rats, RNA expression of the genes assayed is linked with ploidy. However, when phenotypically different SMC cultures derived from newborn and adult rats were compared, transcription levels varied from gene to gene and not linked with the ploidy. Thus, differences in gene expression due to polyploidy are superimposed on those due to other phenotypical features.