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Biomedical subjects

P H Spauwen

Publications and source records attributed to P H Spauwen.

At least 19 recordsLinked to original sources
PubMed2001

Influence of rhBMP-2 on rat bone marrow stromal cells cultured on titanium fiber mesh.

Titanium (Ti) fiber mesh is a candidate scaffold material for the creation of bone graft substitutes (BGS). Two densities (3.54 x 10(4) cells/cm(2) [LD or low density] and 3.54 x 10(5) cells/cm(2) [HD or high density]) of rat bone marrow stromal cells were seeded on Ti-fiber mesh discs. Cells were cultured for up to 16 days, 7 days of which the cells were in the presence of various concentrations of rhBMP-2 (0, 10, 100, and 1,000 ng/mL) in order to evaluate osteogenic expression. Scanning electron microscopy (SEM), light microscopy (LM), energy dispersive spectroscopy (EDS), DNA and calcium (Ca) content measurements, and x-ray diffraction (XRD) analysis were performed. SEM and EDS evaluation showed that a confluent layer of cells was present on top of the meshes together with collagen bundles and calcified globular accretions. Light microscopical evaluation showed a densely stained layer in the upper part of the mesh. SEM and Ca content measurement showed that calcification starts at 8 days. In addition, it was demonstrated that DNA content peaked at 8 days. LM, SEM, and Ca content evaluation revealed positive effects of increasing the cell seeding density, the rhBMP-2 concentration and the culture time on mineralization. Increasing the cell seeding density also showed a positive effect on DNA content. No effects of rhBMP-2 concentration were seen on DNA content. Finally, XRD revealed that the deposited matrix contained a precipitate of a stable calcium phosphate phase. We conclude that (1) titanium fiber mesh sustains excellent osteogenic expression in vitro, (2) increasing the cell seeding density has a positive effect on osteogenic expression in titanium mesh in vitro, and (3) in high density specimens, rhBMP-2 concentrations of 100 ng/mL and 1,000 ng/mL stimulate extracellular matrix calcification in a dose-responsive manner.

Animals↗
PubMed2001

Ectopic bone formation in titanium mesh loaded with bone morphogenetic protein and coated with calcium phosphate.

The osteoinductive properties of porous titanium fiber mesh, with or without a calcium phosphate coating and loaded with recombinant human bone morphogenic protein-2 (rhBMP-2) or rhBMP-2 and native bovine BMP (S-300) were investigated in a rat ectopic assay model. A total of 112 calcium phosphate-coated and 112 noncoated porous titanium implants, either loaded with rhBMP-2 and S-300 or loaded with rhBMP-2 alone, were subcutaneously placed in 56 Wistar-King rats. The rats were killed 5, 10, 20, and 40 days postoperatively, and the implants were retrieved. Histologic analysis demonstrated that all growth factor and carrier combinations induced ectopic cartilage and bone formation at 5 and 10 days, respectively. At 20 days, bone formation increased and was characterized by trabecular bone and bone marrow-like tissue. At 40 days, more lamellar bone and hemopoietic bone marrow-like tissue were present. At both times, more bone had been formed in calcium phosphate-coated implants than in noncoated samples. Further, in rhBMP-2 and S-300-loaded specimens, bone formation was higher than in rhBMP-2 only-loaded specimens. In rhBMP-2 only-loaded specimens, bone formation was mainly localized inside the mesh material, whereas in specimens loaded with both rhBMP-2 and S-300, the bone was localized inside and surrounding the titanium mesh. The histological findings were confirmed by calcium content and alkaline phosphatase activity measurements. In addition, all specimens showed osteocalcin expression as early as 5 days postoperatively. Our results show that the combination of titanium mesh with BMPs can induce ectopic bone formation and that this bone formation seems to be similar to "enchondral" ossification. In addition, a thin calcium phosphate coating can have a beneficial effect on the bone-inducing properties of a scaffold material. Finally, rhBMP-2 and native BMP act synergistically in ectopic bone induction.

Alkaline Phosphatase↗
PubMed2001

Lip movement in patients with a history of unilateral cleft lip.

OBJECTIVE: The influence of a repaired cleft lip on the stability of coordination between upper and lower lip in nonspeech and speech tasks was investigated. DESIGN: First, we looked at the effects of a secondary cleft lip repair in three individuals. Second, we compared subjects with a history of repaired unilateral cleft lip and subjects with no history of cleft lip (controls). Lip coordination was measured using continuous estimates of relative phase. PARTICIPANTS: Subjects were nine children and adolescents with a primary unilateral cleft lip and palate repair and 4 participants without cleft matched for age across different age categories. RESULTS: In general, the averaged relative phase angle (RPA) angle values were smaller than 180 degrees, indicating an upper lip lead for lip closure. Controls showed a tendency toward a more symmetric type of coordination (close to 180 degrees), compared with subjects with a repaired unilateral cleft lip. The controls also showed less variation in coordination between the lips. For the more complex speech tasks, a general increase in variability of the RPA values for all subjects was observed, most likely suggesting a more flexible type of coordination. Regarding the effect of a secondary cleft lip repair, only one of the three patients showed a clearly less symmetric and less stable type of coordination, compared with preoperation results. CONCLUSIONS: There appear to be differences in lip coordination between speakers without and speakers with a repaired unilateral cleft lip. Furthermore, it seems that the stability of lip coordination tends to increase with age.

Adolescent↗
PubMed2000

[Fifty years of plastic surgery in the Netherlands. IV. Treatment of children with cleft lip and palate].

During the last decades treatment of patients with cleft lip and palate exchanged a solitary for a multidisciplinary approach. This warrants a balanced development of cranio-maxillofacial growth yielding good results both in restoring facial contour and correcting functional defects. Nowadays, refinements in indications for treatment and in techniques, based upon scientific evidence are the goals. In the future more basic studies in the genetical and ecological field may provide tools for patient tailored counselling and effective prevention.

Child↗
PubMed2000

Bone formation in calcium-phosphate-coated titanium mesh.

The osteogenic activity of porous titanium fiber mesh and calcium phosphate (Ca-P)-coated titanium fiber mesh loaded with cultured syngeneic osteogenic cells was compared in a syngeneic rat ectopic assay model. In 30 syngeneic rats, (Ca-P)-coated and non-coated porous titanium implants were subcutaneously placed either without or loaded with cultured rat bone marrow (RBM) cells. Fluorochrome bone markers were injected at 2, 4, and 6 weeks. The rats were sacrificed, and the implants were retrieved at 2, 4, and 8 weeks post-operatively. Histological analysis demonstrated that none of the (Ca-P)-coated and non-coated meshes alone supported bone formation at any time period. In RBM-loaded implants, bone formation started at 2 weeks. At 4 weeks, bone formation increased. However, at 8 weeks bone formation was absent in the non-coated titanium implants, while it had remained in the (Ca-P)-coated titanium implants. Also, in (Ca-P)-coated implants more bone was formed than in non-coated samples. In general, osteogenesis was characterized by the occurrence of multiple spheres in the porosity of the mesh. The accumulation sequence of the fluorochrome markers showed that the newly formed bone was deposited in a centrifugal manner starting at the center of a pore. Our results show that the combination of Ti-mesh with RBM cells can indeed generate bone formation. Further, our results confirm that a thin Ca-P coating can have a beneficial effect on the bone-generating properties of a scaffold material.

Animals↗
PubMed2000

The long-term effects of force-transmission in an injured wrist, measured with dual-energy X-ray absorphometry: a case report.

PURPOSE: To investigate the feasibility of using a dual-energy X-ray absorphometry (DEXA) scan to predict long-term force-transmission patterns in wrists. MATERIAL AND METHODS: Both wrists of a man with morbid Kienböck stage IIIa disease of his left wrist (avascular necrosis of the lunate) were examined by a DEXA scan to determine the differences in bone density in the distal radius. RESULTS: In the distal radius of the injured wrist, a shift in bone density was seen toward the scaphoid fossa, which resembles the shift in force-transmission pattern described in force-transmission studies of the wrist. CONCLUSIONS: These differences can be interpreted as a result of an altered force-transmission pattern in the injured wrist.

Absorptiometry, Photon↗
PubMed2000

[Team management of orofacial clefts].

In the Netherlands 15 centres provide multidisciplinary care for cleft lip and palate patients. Usually the following disciplines participate in such teams: paediatrics, plastic and reconstructive surgery, orthodontics, genetics, social work or nursing, ENT, speech therapy, maxillofacial surgery, prosthetic dentistry, psychology and oral hygiene. An overview is given of the treatment protocol from birth until 20 years of age for a child with a complete UCLP or BCLP. It is concluded that properly designed prospective clinical trials are rare, resulting in a lack of evidence based care in the field of cleft lip and palate. Furthermore it should be investigated whether it is preferable to centralise the cleft care in less centres than the present 15 ones.

Adolescent↗
PubMed1999

Nonsyndromic orofacial clefts: association with maternal hyperhomocysteinemia.

Maternal folic acid supplementation has been suggested to play a role in the prevention of nonsyndromic orofacial clefts, i.e., cleft lip +/- cleft palate. Using a case-control design, we investigated vitamin-dependent homocysteine metabolism in 35 mothers with nonsyndromic orofacial cleft offspring and 56 control mothers with nonmalformed offspring. A standardized oral methionine loading test was performed, in which fasting and afterload plasma total homocysteine, serum and red-cell folate, serum vitamin B12, and whole-blood vitamin B6 levels were determined. We found that both fasting (P < 0.01) as well as afterload (P < 0.05) homocysteine concentrations were significantly higher in cases compared to controls. Hyperhomocysteinemia, defined by a fasting and/or afterload homocysteine concentration above the 97.5th percentile, was present in 15.6% of the cases and in 3.6% of controls (odds ratio, 5.3 (1.1-24.2)). The median concentrations of serum (P < 0. 01) and red-cell (P < 0.05) folate were significantly higher, and vitamin B6 concentrations appeared to be significantly lower (P < 0. 05), in cases compared with controls. No significant difference was observed between groups for vitamin B12. These preliminary data offer evidence that maternal hyperhomocysteinemia may be a risk factor for having nonsyndromic orofacial cleft offspring.

Adult↗
PubMed1999

Transposition of the rectus abdominis muscle for complicated pouch and rectal fistulas.

PURPOSE: Operative repair for complicated pouch and rectal fistulas is often difficult. We present our experience with ten consecutive patients operated on for complicated pouch and rectal fistulas by transposition of the rectus abdominis muscle. METHODS: Ten patients with high and complex pouch and rectal fistulas were treated with the interposition of a vascularized rectus abdominis muscle flap. All patients received standard bowel preparation and antibiotics. All were diverted by a temporary ileostomy. RESULTS: Causes of fistulas included Crohn's disease (n = 3), previous rectal surgery (n = 5), anal atresia (n = 1), and sphincter repair (n = 1). Three patients had a third recurrence. The procedure was performed in combination with a plastic surgeon. All fistulas healed. No special postoperative care was required. There were no cosmetic or functional complaints caused by transposition of the rectus abdominis muscle. CONCLUSIONS: Transposition of the rectus abdominis muscle is a suitable technique in treatment of fistulas between the rectum or ileal pouch and the vagina or urinary system, with no obvious side effects and excellent clinical outcome.

Adult↗
PubMed1998

PLink, plastic surgery and the Internet.

The Internet is a fast growing, global computer network that is easy to access at a low cost. This form of communication allows rapid electronic exchange of information such as text, pictures, animations, video and sound. This offers physicians an opportunity to enhance the quality of patient care, research and communication with colleagues. Patients who previously had limited access to information concerning diseases and treatment options are now able to find medical information on the Internet. The quality of information found on the Internet varies widely, from the most up-to-date protocols, produced by leading physicians and surgeons, to out of date or inaccurate recommendations. Faced with an enormous quantity of information of variable quality, guidelines certified by recognised medical organisations are essential to provide websites with valuable information. This so-called "safe house principle" creates reliable places on the Internet ("safe houses") that are generally accepted and trusted for containing valid information. We have created such a "safe house" on plastic surgical topics for the Netherlands Society for Plastic Surgery called "PLink" (the Plastic Surgery link). Its goals are: 1. to provide a well-organised list of existing plastic surgery Internet resources; 2. to improve communication; and 3. to provide original information on plastic surgical subjects for patients and physicians. Professionals always review the content. Since July 1996 our files have been accessed over 1.3 million times in 17 months, with the visit rate increasing from 1470 in July 1996 to 4200 in March 1997 and remaining stable since then. This indicates that there is a growing need for high quality information on plastic surgery on the Internet.

Communication↗
PubMed1998

Preoperative injection using a diluted anesthetic/adrenaline solution significantly reduces blood loss in reduction mammaplasty.

Breast reductions are very common operations in the plastic surgical practice. The cosmetic results are generally satisfactory but are often accompanied with large volumes of blood lost. In this study, the reduction of blood loss together with other positive and negative effects of a preoperatively diluted anesthetic/adrenaline solution was tested. A group of 41 female patients treated with the infiltration solution was compared with a group of 29 female patients treated without the solution. No statistical differences were found in age at operation, weight, length, Quetelet index, amount of tissue resected, preoperative hemoglobin and hematocrit, postoperative drainage, duration of operation, and the viability of the skin flaps (p > 0.05). Blood loss was significantly less in the adrenaline-treated group measured in several ways (p < 0.0001). There were more adrenaline-treated patients with less hospitalization time compared with the nontreated group (p = 0.0858). In conclusion, diluted anesthetic/adrenaline solution significantly reduces blood loss in reduction mammaplasty without any adverse effects.

Adolescent↗
PubMed1998

The use of silicone occlusive sheeting (Sil-K) and silicone occlusive gel (Epiderm) in the prevention of hypertrophic scar formation.

The development of hypertrophic scars and keloids is an unsolved problem in the process of wound healing. For this reason, a successful treatment to prevent excessive scar formation still has not been found. Over the last decade, however, a promising new treatment has been introduced. Silicone materials have proved to reduce the amount of scar tissue and are believed even to prevent hypertrophic scar and keloid formation. In this study, the prophylactic effect of a silicone occlusive sheeting (Sil-K, Degania, Israel) and a silicone occlusive gel (Epiderm, Inamed B.V., The Netherlands) was investigated in a bilateral breast-reduction scar model in which the nontreated scars were supported by nonocclusive Micropore (3M, The Netherlands). The inframammary scars of 129 female patients with a mean age of 31 years ( 14 to 69 years) were studied up to 1 year after the operation. The width and height were measured, and B-scan ultrasound, laser-Doppler flowmetry, and color measurements were used as objective indicators to distinguish between normal and exuberant scars. Three months following the operation, 64.3 percent of the patients developed a hypertrophic scar, which was reduced to 56.6 percent after 6 months and down to 35.3 percent after 1 year. No keloids were seen. Patients with an easily tanning skin, nonsmokers, and patients with an allergy showed more hypertrophic scar formation. Neither Sil-K, used in 68 patients, nor Epiderm, used in 61 patients, could prevent the formation of hypertrophic scars. If both groups were taken together, the scars treated with silicone materials even developed significantly more hypertrophy compared with the Micropore-applicated scars.

Adolescent↗
PubMed1997

The role of suture material in hypertrophic scar formation: Monocryl vs. Vicryl-rapide.

The development of hypertrophic scars and keloids is an unsolved problem in the process of wound healing. There are indications that inflammation plays an important role in this process, but its exact mechanism remains unclear. In this study the amount of inflammation and the development of hypertrophic scars and keloids was investigated in inframammary skin incisions sutured with synthetic absorbable suture materials: a monofilamentous suture (Monocryl) compared with a multifilamentous suture (Vicryl-rapide). In 81 breast reduction patients Monocryl (N = 28) has proved to give significantly smaller, less reactive scars with a lower tendency toward hypertrophic scar formation compared with Vicryl-rapide (N = 53).

Abscess↗
PubMed1997

[Soft tissue injuries of the face].

Traumatic lesions of the soft tissues of the face may have an important social impact in affecting vital functions of the face as well as esthetics. Despite of some tolerance in adapting to tissue loss, major tissue of the face needs to be reconstructed at all levels. Primary treatment is most successful if reconstructions are performed atraumatically, using well vascularized tissues and respecting the esthetic units of the face. Functional structures such as the eye lids, the lips, the facial nerve and the parotid duct should be repaired as a primary procedure. Scar maturation is a prerequisite before performing secondary corrections.

Esthetics↗