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Biomedical subjects

S Lozanoff

Publications and source records attributed to S Lozanoff.

At least 19 recordsLinked to original sources
PubMed2001

Immunohistochemical localization of Pax2 and associated proteins in the developing kidney of mice with renal hypoplasia.

Pax2 has been identified as a key regulatory protein associated with renal developmental malformations. The purpose of this study was to determine whether Pax2 protein expression, and that of other proteins important for normal renal development, is abnormally distributed in the prenatal kidney of the Brachyrrhine (Br) mouse that displays heritable renal hypoplasia. Embryonic 3H1 +/+ and Br/Br mice were collected between E11.0 and E18.0. Routine light microscopy and immunohistochemical analysis using antibodies to Pax2, E-cadherin, fibronectin, laminin, and Type IV collagen were applied to sequential tissue sections. E-cadherin stained consistently in the renal tubules of both normal and mutant animals. Whereas the initial expression of Pax2 corresponded between normal and mutant kidneys, it became progressively limited to the nephrogenic zone in +/+ animals, while distributing erratically in the Br/Br kidney. Fibronectin was not expressed in the normal nephrogenic zone but remained abundantly distributed throughout the Br/Br kidney. Luminin and Type IV collagen staining revealed a deficiency in renal vasculature formation in Br/Br kidneys. Results suggest that initial morphological differentiation occurs normally in the Br kidney but that subsequent nephric formation is associated with abnormal distribution of Pax2 and ECM proteins. (J Histochem Cytochem 49:1081-1097, 2001)

Animals↗
PubMed2000

Levator claviculae muscle discovered during physical examination for cervical lymphadenopathy.

During a routine physical examination of an adult female with a history of breast cancer and cervical lymphadenopathy, a mass was noted in the right supraclavicular region. The mass was unilateral and easily palpable along the superior border near the median aspect of the clavicle. Plain film radiography, performed to determine whether the mass represented an enlarged jugulo-omohyoid lymph node, revealed an elongated opaque mass in this region. Computed tomographic (CT) and magnetic resonance (MR) images were subsequently obtained. Sequential axial CT scans revealed a cylindrical mass that appeared to be independent of contiguous muscles, including the sternocleidomastoid, anterior, and middle scalene muscles. This mass attached inferiorly to the clavicle and superiorly to the transverse process of the sixth cervical vertebra. Sagittal, coronal, and axial MR scans confirmed the presence of a well-defined superficial mass. It is concluded that the mass represents a levator claviculae (cleidocervical) muscle. This observation underscores the importance of understanding soft tissue variants that may be encountered during a routine physical examination.

Adult↗
PubMed2000

Comparison of mandibular morphology in Korean and European-American children with Class III malocclusions using finite-element morphometry.

The purpose of this study was to determine whether the morphology of the mandible differed in subjects of diverse ethnic origin exhibiting Class III malocclusions. Lateral cephalographs of 147 children of either Korean or European-American descent aged between 5 and 11 years were compared. The cephalographs were subdivided into seven age- and sex-matched groups, traced, and eight mandibular homologous landmarks digitized. Average mandibular geometries, scaled to an equivalent size, were computed using Procrustes superimposition and subjected to ANOVA. Graphical analysis using a colour-coded finite element (FEM) programme was used to localize differences in morphology. Results indicated that the overall mean Korean and European-American mandibular configurations differed statistically (P < 0.001) and statistical difference was maintained at all age-wise comparisons. Comparing Korean and European-American Class III mandibular configurations for local size-change, FEM analysis revealed that the Korean condylar and mental regions generally were smaller (approximately 15-20 per cent decrease in size, respectively). However, an antero-posterior increase in the size of the mandibular corpus was most apparent in the incisor alveolus region (approximately 35 per cent increase in size). For shape-change, the Korean and European-American mandibular configurations were fairly isotropic except in the symphyseal and incisor alveolus regions. Dissimilarities in mandibular morphology are identifiable particularly in the dento-alveolar regions in subjects of diverse ethnic origin exhibiting Class III malocclusions. These differences may reflect genetic and/or environmental influences that might determine the severity and prevalence of the condition, and its subsequent clinical management.

Asian People↗
PubMed1999

Spatial and temporal distribution of cellular proliferation in the cranial base of normal and midfacially retrusive mice.

The craniofacial region of the Brachyrrhine (Br) mouse is characterized by a retruded midface. The cellular mechanism causing this growth deficiency is unknown. However, the cranial base is foreshortened in adult Br mice. The purpose of this study was to determine whether the spatial and temporal patterns of cellular proliferation in the cranial base (CB) differ between normal (C3H/HeJ) and Br mutant (3H1 Br/+) embryonic mice. Twenty-four dams were injected (3)H thymidine (5 microCi/gram body weight) and 15 embryos from each group were collected at Theiler stages 23, 25, and 27 (15, 17, and 19 days of gestation). Serial sections from each head were processed with routine autoradiography. Labelling indices (LI) were determined for each specimen and cellular proliferation maps were generated for each age group. LI patterns within and between groups were compared statistically. Results showed that cellular proliferation in the CB of normal embryos displayed a time- and position-dependent pattern, characteristic of transient growth sites (TGS). Generally, as age increases, cellular proliferative activities decrease gradually (from an average LI of 11.4 +/- 5.7% at stage 23 to 4.4 +/- 2.2% at stage 27), and the number of the TGS decreases in the presumptive nasal septal region and increases in presumptive sphenoethmoidal area with age, indicating the existence of cellular subpopulations in the CB. Cellular proliferation in the CB of the Br mutant displays a different growth pattern compared to the normal condition. Deficiencies in cellular proliferation exist mainly in the presumptive sphenoethmoidal area of the CB. The results indicate that the TGS play an important role in the normal morphogenesis of the CB, and abnormalities in their timing and/or position may be responsible for the dysmorphology of the midface in the Br mutant.

Animals↗
PubMed1999

Finite-element morphometry of soft tissues in prepubertal Korean and European-Americans with Class III malocclusions.

The purpose was to test the hypothesis that soft-tissue morphology differs consistently in people of diverse ethnic origin exhibiting Class III malocclusions. Lateral cephalographs of 70 Korean and 71 European-American children aged between 5 and 11 years were traced and 12 homologous, soft-tissue landmarks digitized. The total sample was subdivided into seven age- and sex-matched groups, and Procrustes superimposition was used to generate average geometries scaled to an equivalent size. Statistical differences were tested by ANOVA. Graphical analysis using a colour-coded finite-element (FEM) program was used to localize differences in morphology. Procrustes' results indicated that the overall mean Korean and European-American soft-tissue configurations differed statistically (p<0.001), and this difference was also true in all seven age groups tested (p<0.001). On comparing mean Korean and European-American Class III soft-tissue configurations for local size change, FEM analysis revealed that whereas the Korean mental regions generally were smaller (approx. 43% on average), local increases in size were apparent for the lower lip (approx. 29% on average). For shape change, the mean Korean and European-American soft-tissue configurations were fairly isotropic except in the region of the columella, lower lip and the anterior part of the mental region. Features of the soft-tissue integument in individuals of diverse ethnic origins appear to be associated with the underlying skeletal Class III morphology.

Americas↗
PubMed1999

Finite-element morphometry of soft tissue morphology in subjects with untreated Class III malocclusions.

Soft tissue dynamics may contribute to maxillomandibular allometry (size-related changes in shape) associated with the development of Class III malocclusions. Lateral cephalographs of 124 prepubertal European American children were traced and 12 soft tissue landmarks were digitized. Resultant geometries were normalized, and Procrustes analysis established the statistical difference (p<0.001) between mean Class III and Class I configurations. Comparing the Class III configurations with normals for size-change, color-coded finite element analysis revealed a superoinferior gradient of positive allometry of the Class III facial nodal mesh. A conspicuous area of negative allometry (approximately 40%) was localized near soft subspinale, with a approximately 70% increase in size in the mental region. For shape-change, the Class III facial mesh was isotropic, except in the anisotropic circumoral regions. Conventional cephalometry revealed that about 50% of linear and 75% of angular parameters differed statistically (p<0.001). Soft tissue dynamics during early postnatal development may contribute to the development of Class III malocclusions.

Case-Control Studies↗
PubMed1999

Allometry of the cranial base in prepubertal Korean subjects with class III malocclusions: finite element morphometry.

Sphenoethmoidal allometry could be associated with ethnic heterogeneity of the midfacial profile. Thirteen cranial base landmarks were digitized from cephalographs of 69 Korean and 73 European American prepubertal children exhibiting Class III malocclusion. Average geometries were normalized, and a color-coded finite element (FEM) program was used to localize differences in morphology. ANOVA indicated that mean Korean and European American cranial base configurations differed statistically (p < 0.01); this was also true for seven age groups tested (p < 0.001). For size-change, FEM analysis revealed that in the anterior cranial base, Korean sphenoethmoidal and sella turcica regions were smaller (=12%). Local increases in size were apparent for the posterior region of the Korean cranial base (=35%). For shape-change, Korean and European American cranial base configurations were isotropic with minor anisotropy in the sphenoethmoidal and spheno-occipital regions. A sphenoethmoidal mechanism of midfacial retrognathism appears to be implicated in the development of a skeletal Class III morphology.

Analysis of Variance↗
PubMed1999

A full color system for quantitative assessment of histochemical and immunohistochemical staining patterns.

Quantitative measures of staining distributions are important to compare the presence and patterns of cells or macromolecules. Typically, achromatic thresholding systems are used to compare staining distributions. Achromatic video signals, however, lack sufficient resolution to identify and compare chromatic changes. The purpose of this study is to describe a full color system for analysis of chromatic staining distributions. The hardware system includes a Leitz Diaplan microscope, video camera, GVP videoboard and Amiga 3000 computer. Software was developed in "C" to partition the video signal into hue (H), saturation (S) and value (V). Also, percentage of stained area was determined. Kodak color filters were used to assess the accuracy and precision of the system. Craniofacial tissues were stained with varying concentrations of toluidine blue and primary anti-BrdU antibodies. HSV and the percentage of stained areas were determined and displayed low coefficients of error. HSV values also performed as expected for standard filters as well as cellular staining concentrations. This system is easily implemented and should be useful for comparing chromatic changes with any color resulting from histochemical or immunohistochemical procedures.

Image Processing, Computer-Assisted↗
PubMed1998

An anomalous accessory flexor digiti minimi profundus muscle: a case study.

A well-developed anomalous muscle within the forearm flexor compartment was discovered during a routine cadaveric dissection. The identified muscle originated from the intercompartmental septum on the medial side of the forearm just proximal to the wrist joint and inserted on the proximal phalanx of the fifth digit. When stressed, the tendon of the muscle produced flexion of the metacarpophalangeal joint of the fifth digit. Contiguous muscles, including the flexor digitorum profundus, displayed normal morphology. The muscle appeared to be an accessory belly of flexor digitorum profundus. The combination of an accessory flexor digitorum profundus muscle belly acting on the metacarpophalangeal joint of the little finger has not been previously reported. Based on its origin, insertion, and action we have named this variant accessory flexor digiti minimi profundus. This muscular variant could have clinical relevance, possibly affecting ulnar nerve function and circulation in the hand.

Aged↗
PubMed1998

Morphometry of the midfacial complex in subjects with class III malocclusions: Procrustes, Euclidean, and cephalometric analyses.

The purpose of this study was to determine whether the morphology of the midface differed in subjects with a retrognathic midfacial appearance (Class III malocclusions) using a combination of morphometric and cephalometric analyses. After obtaining appropriate consent, lateral cephalographs of 133 children of European-American descent, ages 5-11 years, were compared: 73 had Class III malocclusion, 60 had normal (Class I) occlusion. The cephalographs were traced and subdivided into seven age- and sex-matched groups. Average geometries based upon seven nodes (pterygoid point, PTS; rhinion, RO; posterior nasal spine, PNS; midpalatal point, MPP; anterior nasal spine, ANS; subspinale, A; prosthion, Pr), scaled to an equivalent size, were compared using a Procrustes routine. Euclidean distance matrix analysis (EDMA) was employed to localize differences in morphology. Bivariate analyses on unscaled data utilizing nine linear and six angular measurements were also undertaken. Results from Procrustes and EDMA analyses indicated that although the overall midfacial configurations differed statistically (P < 0.05), only about half of the seven age sub-groups maintained significance. Similarly, only four of the nine linear measures (PNS-MPP, MPP-ANS, A-Pr and PTS-RO) and two of the six angular parameters (PTS-RO-ANS and ANS-A-Pr) tested were significantly different (P < 0.05). Therefore, midfacial morphometric variability and morphological diversity may mask statistical differences. It is concluded that the midface may be the defining craniofacial component in the final appearance of Class III malocclusions compared to other craniofacial components, including the cranial base and mandible.

Cephalometry↗
PubMed1998

Procrustes, Euclidean and cephalometric analyses of the morphology of the mandible in human Class III malocclusions.

The role of mandibular phenotype in the development of Class III malocclusion remains unclear. The purpose of this study was to determine whether the form of the mandible differed between prepubertal individuals with Class I and Class III malocclusions. Lateral cephalographs of 73 children of European-American descent aged between 5-11 years with Class III malocclusion were compared to those of 60 counterparts with a normal, Class I molar occlusion. The cephalographs were traced and checked, and eight homologous mandibular landmarks were digitized. Average mandibular geometries, scaled to an equivalent size, were generated using Procrustes superimposition. Euclidean distance matrix analysis (EDMA) was undertaken to corroborate the Procrustes analysis, and bivariate analysis utilizing eight linear and five angular measurements was also performed. Residuals and F-values from Procrustes analysis indicated that mandibular configurations differed statistically for Class I and Class III types. EDMA confirmed that the Class I and Class III geometries were significantly different, revealing that the greatest differences in morphology arose in the anterior-most mandibular regions. As well, most variables showed statistically significant differences when the Class I and Class III mandibular types were compared. When the sample was subdivided into seven age- and sex-matched groups, nearly all age-based comparisons were significantly different. It is concluded that the morphology of the mandible differs in individuals with Class III malocclusions when compared to the normal Class I configuration, and that these alterations may indicate dichotomous postnatal mandibular ontogeny.

Cephalometry↗
PubMed1998

Mandibular morphology in subjects with Class III malocclusions: Finite-element morphometry.

The absence of physical restraint may be associated with a mandibular allometry that contributes to mandibular prognathism. Cephalographs of 73 prepubertal children of European American descent with untreated Class III malocclusions were traced and eight mandibular landmarks digitized. The resulting eight-noded geometries were normalized, and the mean Class III geometry compared with the equivalent Class I average. Procrustes analysis established statistical difference (p < 0.05) between these mean configurations. A color-coded finite-element (FEM) analysis was used to localize differences in morphology. Comparing Class III and normal mandibular configuration for changes in size, FEM revealed positive allometry of the mandibular corpus and around supramentale (15% increase in size), with reductions (30%) between the incisor alveolus and menton. For changes in shape, mandibular configurations were predominantly isotropic, with the exception of the anisotropic anterior region in the Class III subjects. Incremental growth differences are consistent with the view that the absence of physical restraint is associated with mandibular prognathism.

Case-Control Studies↗
PubMed1998

Cleft palate formation in fetal Br mice with midfacial retrusion: tenascin, fibronectin, laminin, and type IV collagen immunolocalization.

OBJECTIVE: This study tested the hypothesis that altered craniofacial morphology does not affect the expression of extracellular matrix (ECM) molecules such as fibronectin (FN), laminin (LN), type IV collagen, and tenascin-C (TN) but is associated with failure of palatal shelf elevation and fusion concomitant with cleft palate formation. DESIGN: To test this hypothesis, a comparative immunohistological analysis of FN, LN, type IV collagen, and TN was undertaken on brachyrrhine (Br/Br) mice and normal (+/+) fetuses during secondary palate formation. Normal and Br/Br fetuses were collected at gestational days E13 and E14 (representing prefusion stages) and E15 and E18 (representing postfusion stages). Cryostat palatal sections (8 microm) were postfixed in methanol, washed, and stained with primary antibody. All sections were washed and coated with secondary antibody (swine-anti-rabbit IgG) and mounted with citifluor. RESULTS: Immunohistological analysis showed that LN and type IV collagen were located near the presumptive medial epithelial seam (MES) or edge (MEE) in +/+ or Br/Br fetuses, respectively. Fibronectin showed a homogeneous distribution at all stages in both groups of mice. In contrast, TN became localized below the presumptive MES or MEE in both groups of mice at E14. In +/+ animals at E15, TN dissipated and became confined to the oral basement membrane by E18. At E15 and E18 in cleft Br/Br mutants, TN stained beneath the MEE. CONCLUSION: Although the distributions of ECM molecules are similar during normal and cleft palatogenesis, differences in TN expression are associated with cleft palate formation.

Animals↗
PubMed1998

Craniofacial heterogeneity of prepubertal Korean and European-American subjects with Class III malocclusions: procrustes, EDMA, and cephalometric analyses.

The purpose of this study is to determine whether there is a difference in craniofacial morphology in subjects of diverse ethnic origin with untreated Class III malocclusions, and thus to examine the validity of using similar therapeutic protocols in their orthodontic management. Lateral cephalographs of 142 Korean and European-American children aged 5 to 11 years were traced, and homologous cranial, midfacial, and mandibular landmarks were digitized. Procrustes analysis and Euclidean Distance Matrix Analysis (EDMA) were performed to identify size-corrected differences of the three craniofacial configurations, and bivariate analysis to determine statistical differences between 42 cephalometric parameters. Procrustes analysis indicated statistical significance for each configuration of landmarks; these results were confirmed by EDMA and cephalometry. Korean children appear to develop Class III malocclusions because of smaller anterior cranial base and midfacial dimensions, exacerbated by a large and less favorable mandibular morphology. Therefore, morphologic diversity of craniofacial components, presumably due to heterochrony during development, contributes to distinctive facial profiles associated with Class III malocclusions. Ethnic heterogeneity may need to be taken into account in the orthodontic management of Class III malocclusions.

Analysis of Variance↗
PubMed1997

Spline analysis of the mandible in human subjects with class III malocclusion.

This study determines deformations that contribute to a Class III mandibular morphology, employing thin-plate spline (TPS) analysis. A total of 133 lateral cephalographs of prepubertal children of European-American descent with either a Class I molar occlusion or a Class III malocclusion were compared. The cephalographs were traced and checked, and eight homologous landmarks on the mandible were identified and digitized. The datasets were scaled to an equivalent size and subjected to statistical analyses. These tests indicated significant differences between average Class I and Class III mandibular morphologies. When the sample was subdivided into seven age and sex-matched groups statistical differences were maintained for each group. TPS analysis indicated that both affine (uniform) and non-affine transformations contribute towards the total spline, and towards the average mandibular morphology at each age group. For non-affine transformations, partial warp 5 had the highest magnitude, indicating large-scale deformations of the mandibular configuration between articulare and pogonion. In contrast, partial warp 1 indicated localized shape changes in the mandibular symphyseal region. It is concluded that large spatial-scale deformations affect the body of the mandible, in combination with localized distortions further anteriorly. These deformations may represent a developmental elongation of the mandibular corpus antero-posteriorly that, allied with symphyseal changes, leads to the appearance of a Class III prognathic mandibular profile.

Age Factors↗
PubMed1997

Localisation of deformations of the midfacial complex in subjects with class III malocclusions employing thin-plate spline analysis.

This study determines deformations of the midface that contribute to a class III appearance, employing thinplate spline analysis. A total of 135 lateral cephalographs of prepubertal children of European-American descent with either class III malocclusions or a class I molar occlusion were compared. The cephalographs were traced and checked, and 7 homologous landmarks of the midface were identified and digitised. The data sets were scaled to an equivalent size and subjected to Procrustes analysis. These statistical tests indicated significant differences (P < 0.05) between the averaged class I and class III morphologies. Thinplate spline analysis indicated that both affine and nonaffine transformations contribute towards the total spline for the averaged midfacial configuration. For nonaffine transformations, partial warp 3 had the highest magnitude, indicating the large scale deformations of the midfacial configuration. These deformations affected the palatal landmarks, and were associated with compression of the midfacial complex in the anteroposterior plane predominantly. Partial warp 4 produced some vertical compression of the posterior aspect of the midfacial complex whereas partial warps 1 and 2 indicated localised shape changes of the maxillary alveolus region. large spatial-scale deformations therefore affect the midfacial complex in an anteroposterior axis, in combination with vertical compression and localised distortions. These deformations may represent a developmental diminution of the palatal complex anteroposteriorly that, allied with vertical shortening of midfacial height posteriorly, results in class III malocclusions with a retrusive midfacial profile.

Cephalometry↗
PubMed1997

Thin-plate spline analysis of the cranial base in subjects with Class III malocclusion.

The role of the cranial base in the emergence of Class III malocclusion is not fully understood. This study determines deformations that contribute to a Class III cranial base morphology, employing thin-plate spline analysis on lateral cephalographs. A total of 73 children of European-American descent aged between 5 and 11 years of age with Class III malocclusion were compared with an equivalent group of subjects with a normal, untreated, Class I molar occlusion. The cephalographs were traced, checked and subdivided into seven age- and sex-matched groups. Thirteen points on the cranial base were identified and digitized. The datasets were scaled to an equivalent size, and statistical analysis indicated significant differences between average Class I and Class III cranial base morphologies for each group. Thin-plate spline analysis indicated that both affine (uniform) and non-affine transformations contribute toward the total spline for each average cranial base morphology at each age group analysed. For non-affine transformations, Partial warps 10, 8 and 7 had high magnitudes, indicating large-scale deformations affecting Bolton point, basion, pterygo-maxillare, Ricketts' point and articulare. In contrast, high eigenvalues associated with Partial warps 1-3, indicating localized shape changes, were found at tuberculum sellae, sella, and the frontonasomaxillary suture. It is concluded that large spatial-scale deformations affect the occipital complex of the cranial base and sphenoidal region, in combination with localized distortions at the frontonasal suture. These deformations may contribute to reduced orthocephalization or deficient flattening of the cranial base antero-posteriorly that, in turn, leads to the formation of a Class III malocclusion.

Case-Control Studies↗