Publications by authors named "A K Lappalainen"

70 Publications

Periosteal Flaps Enhance Prefabricated Engineered Bone Reparative Potential.

J Dent Res 2021 Sep 11:220345211037247. Epub 2021 Sep 11.

Department of Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.

The clinical translation of bone tissue engineering for reconstructing large bone defects has not advanced without hurdles. The bioreactor (IVB) concept may therefore bridge between bone tissue engineering and reconstructive surgery by employing the patient body for prefabricating new prevascularized tissues. Ideally, IVB should minimize the need for exogenous growth factors/cells. Periosteal tissues are promising for IVB approaches to prefabricate tissue-engineered bone (TEB) flaps. However, the significance of preserving the periosteal vascular supply has not been adequately investigated. This study assessed muscle IVB with and without periosteal/pericranial grafts and flaps for prefabricating TEB flaps to reconstruct mandibular defects in sheep. The sheep ( = 14) were allocated into 4 groups: muscle IVB (M group; = 3), muscle + periosteal graft (MP group; = 4), muscle + periosteal flap (MVP group; = 4), and control group ( = 3). In the first surgery, alloplastic bone blocks were implanted in the brachiocephalic muscle (M) with a periosteal graft (MP) or with a vascularized periosteal flap (MVP). After 9 wk, the prefabricated TEB flaps were transplanted to reconstruct a mandibular angle defect. In the control group, the defects were reconstructed by non-prevascularized bone blocks. Computed tomography (CT) scans were performed after 13 wk and after 23 wk at termination, followed by micro-CT (µCT) and histological analyses. Both CT and µCT analysis revealed enhanced new bone formation and decreased residual biomaterial volume in the MVP group compared with control and MP groups, while the M group showed less new bone formation and more residual biomaterial. The histological analysis showed that most of the newly formed bone emerged from defect edges, but larger areas of new bone islands were found in MP and MVP groups. The MVP group showed enhanced vascularization and higher biomaterial remodeling rates. The periosteal flaps boosted the reconstructive potential of the prefabricated TEB flaps. The regenerative potential of the periosteum was manifested after the transplantation into the mechanically stimulated bony defect microenvironment.
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http://dx.doi.org/10.1177/00220345211037247DOI Listing
September 2021

Persistent fontanelles in Chihuahuas. Part I. Distribution and clinical relevance.

J Vet Intern Med 2021 Jul 24;35(4):1834-1847. Epub 2021 May 24.

Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Background: The Chihuahua dog breed is known for frequent occurrence of a bregmatic fontanelle on the dorsal skull. A common conception is that this skull defect is a clinically irrelevant finding. No studies, however, describe its prevalence or whether it is accompanied by other persistent fontanelles (PFs). Although Chihuahuas are predisposed to Chiari-like malformation (CM) and syringomyelia (SM), it is unknown whether PFs occur more commonly in dogs with clinical signs that are caused by CM or SM.

Hypothesis/objectives: To describe the number and location of PFs at cranial sutures (CSs) and to compare the occurrence of these PFs in dogs with and without CM/SM-related clinical signs. We hypothesized that PFs also occur commonly at lateral and caudal cranial surfaces, affect a higher number of CSs, and are larger in dogs with CM/SM-related clinical signs.

Animals: Fifty client-owned Chihuahuas with or without CM/SM-related clinical signs.

Results: Of the 50 dogs evaluated, 46 (92%) had either 1 or several PFs. The mean ± SD number of PFs was 2.8 ± 3.0 (range, 0-13). A total of 138 PFs occupied 118 CSs with 57 (48%) located dorsally, 44 (37%) caudally, and 17 (14%) laterally. The number of CSs affected by PFs was significantly higher (P ≤ .001) and total PF area was significantly larger (P = .003) in dogs with CM/SM-related clinical signs.

Conclusions And Clinical Importance: Persistent fontanelles are very common in this group of Chihuahuas and appear at dorsal, lateral, and caudal cranial surfaces. They are more numerous and larger in Chihuahuas with CM/SM-related clinical signs.
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http://dx.doi.org/10.1111/jvim.16151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8295709PMC
July 2021

Persistent fontanelles in Chihuahuas. Part II: Association with craniocervical junction abnormalities, syringomyelia, and ventricular volume.

J Vet Intern Med 2021 Jul 3;35(4):1848-1856. Epub 2021 May 3.

Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Background: Persistent fontanelles (PFs) are, in Chihuahuas, almost ubiquitous. Furthermore, Chihuahuas are predisposed to other craniomorphological abnormalities, including syringomyelia (SM), ventriculomegaly, and craniocervical junction (CCJ) overcrowding resulting in neural tissue deviation. It is, however, undetermined if PFs are more common in dogs with these structural abnormalities, and their etiology is unknown.

Hypothesis/objectives: Persistent fontanelles are more numerous and larger in Chihuahuas with low body weight, older age, SM, dilated fourth ventricle, ventriculomegaly, and CCJ overcrowding.

Animals: Fifty client-owned Chihuahuas.

Methods: Cross-sectional study evaluating the association of both the number of cranial sutures affected by PFs (NAS) and total fontanelle area (TFA), based on computed tomography with SM, fourth ventricle dilatation, lateral ventricle volume, and extent of neural tissue compression at the CCJ based on magnetic resonance images.

Results: The NASs was higher and TFA larger in dogs with low body weight (NAS: P = .007; 95% confidence interval [CI] = 0.384-0.861; TFA: P = .002; 95% CI = -1.91 to -0.478), larger lateral ventricles (NAS: P ≤ .001; 95% CI = 1.04-1.15; TFA: P ≤ .001; 95% CI = 0.099-0.363), and more severe neural tissue compression at the CCJ (NAS: P ≤ .001; 95% CI = 1.26-2.06; TFA: P = .03; 95% CI = 0.066-1.13). Similarly, dogs with SM (NAS: P = .004; 95% CI = 1.26-3.32; TFA: mean ± SD, 130 ± 217 mm ; P = .05) had higher NAS and larger TFA than did dogs without SM (43.7 ± 61.0 mm ). Age was not associated with NAS (P = .81; 95% CI = 0.989-1.01) or TFA (P = .33; 95% CI = -0.269 to 0.092).

Conclusions And Clinical Importance: Persistent fontanelles are associated with small size, SM, ventriculomegaly, and CCJ overcrowding.
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http://dx.doi.org/10.1111/jvim.16123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8295681PMC
July 2021

Reliability of a New Bite Force Measure and Biomechanics of Modified Long Attack in Police Dogs.

Animals (Basel) 2021 Mar 18;11(3). Epub 2021 Mar 18.

Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 57 (Viikintie 49), 00014 Helsinki, Finland.

Information on the biomechanics of police dogs' tasks is important in understanding their work-related injuries and dysfunctions. This study aimed to develop and test a measurement tool for dogs' functional bite force and to report modified long attack-related kinetic and kinematic values. Twenty Finnish male police dogs, 7 German Shepherd Dogs (GSDs) and 13 Belgian Shepherd Dogs, Malinois (BSDMs), were included. Dogs accelerated 25 m and bit the helper's sleeve, fitted with three force sensors. Dogs were wearing a 3D accelerometer and were videotaped with a high-speed camera. The sleeve's reliability for measuring the dog's bite force was evaluated via intraclass correlation and Cronbach's alpha. Otherwise, a Mann-Whitney U-test was used, with significance set at = 0.05. The sleeve's test-retest reliability was moderate to good (intraclass correlation of 0.75), and internal consistency was high (Cronbach's alpha 0.75). The GSDs' median bite force was 360.4 N (interquartile range (IQR) 628.6 N) and BSDMs' 247.0 N (IQR 289.8 N). Median acceleration maximum was 7.1 gravitational force equivalent (g) and median deceleration maximum was 11.6 g, with highest recorded forces being 9.2 g and 13.1 g, respectively. The measurement sleeve was a reliable tool for measuring functional bite force in GSDs and BSDMs. Forces related to bite, approach and impact in the two breeds were reported.
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http://dx.doi.org/10.3390/ani11030874DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003291PMC
March 2021

Canine DVL2 variant contributes to brachycephalic phenotype and caudal vertebral anomalies.

Hum Genet 2021 Feb 18. Epub 2021 Feb 18.

Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland.

A frameshift deletion variant in the Wnt pathway gene dishevelled 2 (DVL2) is associated with a truncated, kinked tail ("screw tail") in English Bulldogs, French Bulldogs and Boston Terriers. These breeds are also characterized by distinctive morphological traits, including a wide head, flat face and short-limbed dwarfism, which are characteristic of Robinow syndrome in humans, caused by defects in genes such as DVL1 and DVL3. Based on these phenotypic and genetic similarities, it has previously been hypothesized that the canine DVL2 variant results in a syndromic phenotype called the Robinow-like syndrome. In our study, we investigated the distribution of the DVL2 variant in 1954 dogs from 15 breeds, identifying breeds with allele variation and enabling the dissection of the genotype-phenotype correlation for the first time. With CT examinations in American Staffordshire Terriers, we confirmed that the DVL2 allele is associated with caudal vertebral malformations and a brachycephalic phenotype. We also hypothesize that the variant may be linked to additional health conditions, including brachycephalic obstructive airway syndrome and congenital heart defects. Altogether, our study strengthens the role of DVL2 as one of the contributors to the "bulldog type" morphology and features on the spectrum of human Robinow syndrome.
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http://dx.doi.org/10.1007/s00439-021-02261-8DOI Listing
February 2021
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