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PubMed1998

Notch signalling mediates segmentation of the Drosophila leg.

The legs of Drosophila are divided into segments along the proximodistal axis by flexible structures called joints. The separation between segments is already visible in the imaginal disc as folds of the epithelium, and cells at segment boundaries have different morphology during pupal development. We find that Notch is locally activated in distal cells of each segment, as demonstrated by the restricted expression of the Enhancer of split mbeta gene, and is required for the formation of normal joints. The genes fringe, Delta, Serrate and Suppressor of Hairless, also participate in Notch function during leg development, and their expression is localised within the leg segments with respect to segment boundaries. The failure to form joints when Notch signalling is compromised leads to shortened legs, suggesting that the correct specification of segment boundaries is critical for normal leg growth. The requirement for Notch during leg development resembles that seen during somite formation in vertebrates and at the dorsal ventral boundary of the wing, suggesting that the creation of boundaries of gene expression through Notch activation plays a conserved role in co-ordinating growth and patterning.

Animals↗
PubMed1992

Uteroplacental diastolic notching in 510 uneventful pregnancies.

In a collective of 510 patients with uneventful pregnancies and deliveries the rate of waveform notching in the uteroplacental flow velocity pattern was examined. Notching appeared to be significantly more frequent in the uterine than arcuate artery. It was unilateral and mainly affected placenta-contralateral sites. Bilateral notching or notching on placental site were the exception. In both flow patterns notching was seen to increase as pregnancy progressed and was slightly higher in the third compared to the second trimester.

Blood Flow Velocity↗
PubMed1995

Notched T wave as evidence of autonomic nervous lability in Duchenne progressive muscular dystrophy.

We investigated the significance of notched T waves on the ECG in 30 patients with Duchenne progressive muscular dystrophy (DMD) and 50 age-matched controls using noninvasive cardiovascular examinations and measurement of urinary catecholamines. Notched T waves were more frequently observed in patients with DMD than in control subjects (46.7% vs. 20.0%, p < 0.05). Moreover, their frequency was age-independent in DMD, whereas they decreased with age in controls. Patients with notched T waves showed significantly increased heart rate, prolonged QTc and augmented excretion of urinary adrenaline compared with patients without them. There were no significant differences in casual BP or incidences of characteristic UCG abnormalities, such as mitral valve prolapse, and ECG abnormalities, such as tall R waves in the right precordial leads, between DMD patients with and without notched T waves. These findings suggest that notched T waves are associated with accelerated sympathetic nervous activity rather than progressive cardiac involvement in DMD.

Adolescent↗
PubMed2004

Alveolar ridge notching as a predictor for secondary bone grafting in incomplete alveolar clefts.

OBJECTIVES: To clarify the need for secondary alveolar bone grafting (ABG) in incomplete alveolar clefts identified clinically from its appearance and test the usefulness of alveolar ridge notching in the edentulous stage as a predictor for ABG. DESIGN: A prospective, cross-sectional study comparing three groups of patients at two stages. PATIENTS: Twenty-four patients with unilateral incomplete cleft of primary palate who underwent either no surgery or cheiloplasty only. METHODS: Cleft severity was assessed at two stages. Initially, the appearance of untreated clefts was assessed before cheiloplasty or at 3 months of age in the patient without cheiloplasty and graded by severity into three groups. Later alveolar bone defects were assessed with computed tomography in the primary or mixed dentition period. A decision regarding the requirement for ABG was then made. Finally, the relationship between untreated clefts and the need for ABG was determined. MAIN OUTCOME MEASURES: Nine (75%) of 12 patients with alveolar ridge notching in the edentulous stage were diagnosed as fulfilling the criteria for ABG. RESULTS: The alveolar bone defects correlated with the severity of untreated cleft conditions (Spearman r = 0.65, p =.002). The need for ABG was greater in patients with alveolar ridge notching, compared with those without notching (9/12 versus 0/12, p =.00034). CONCLUSIONS: Most patients with incomplete alveolar clefts clinically identified in the edentulous stage required ABG, and alveolar ridge notching in the edentulous stage could therefore serve as a predictor for ABG.

Alveolar Process↗
PubMed2002

The morphology of the mandibular antegonial notches and facial symmetry.

Thirty randomly selected pre-treatment postero-anterior cranial radiographs of adolescent patients attending the orthodontic department, School of Dental Medicine, State University of New York at Buffalo comprised the sample in this study. The aims of this study were (1) to compare the depths of the right, and the left, mandibular antegonial notches, and (2) to determine whether the morphology of the antegonial notches bears a statistical relationship to some other transverse metrical characters of the face. The frontal cranial radiographs of thirty patients were digitized to determine the linear, and surface area, measurements of the right, and the left, antegonial notches as well as some transverse dimensions of the faces. An analysis of variance showed that no statistically significant difference existed between the measurements made by the two examiners, who digitized the radiographs. The data were analyzed by means of the Student's t-test. The results showed that there were statistically significant differences (P<0.05) between the measurements of the right, and the left, mandibular antegonial notches. The data also showed that there were highly statistically significant differences between the corresponding bilateral facial dimensions (P<0.001). The results of this study suggest that facial symmetry, as measured on a frontal skull radiograph, is associated with the respective depths of the right, and the left, mandibular antegonial notches.

Adolescent↗
PubMed2003

Osteoporosis and anterior femoral notching in periprosthetic supracondylar femoral fractures: a biomechanical analysis.

BACKGROUND: This biomechanical study was designed to evaluate the predictive ability of dual-energy x-ray absorptiometry, cortical bone geometry as determined with computed tomography, and radiography in the assessment of torsional load to failure in femora with and without notching. METHODS: Thirteen matched pairs of cadaveric femora were randomized into two groups: a notched group, which consisted of femora with a 3-mm anterior cortical defect, and an unnotched group of controls. Each pair then underwent torsional load to failure. The ability of a number of measures to predict femoral torsional load to failure was assessed with use of regression analysis. These measures included dual-energy x-ray absorptiometry scans of the proximal and the distal part of the femur, geometric measures of both anterior and posterior cortical thickness as well as the polar moment of inertia of the distal part of the femur as calculated on computed tomography scans, and the Singh osteoporosis index as determined on radiographs. RESULTS: The torsional load to failure averaged 98.9 N-m for the notched femora and 143.9 N-m for the controls; the difference was significant (p < 0.01). Although several variables correlated with torsional load to failure, distal femoral bone-mineral density demonstrated the highest significant correlation (r = 0.85; p < 0.001). Moreover, multiple regression analysis showed that a combination of distal femoral bone-mineral density and polar moment of inertia calculated with the posterior cortical thickness (adjusted r (2) = 0.79; p < 0.001) had the strongest prediction of torsional load to failure in the notched group. The addition of other measures of cortical bone geometry, proximal femoral bone-mineral density, or radiographic evidence of osteopenia did not significantly increase the model's predictive ability. CONCLUSIONS: Femoral notching significantly decreases distal femoral torsional load to failure and is best predicted by a combination of the measures of distal femoral bone-mineral density and polar moment of inertia. Together, these values account for the amount of bone mass present and the stability provided by the cortical shell architecture.

Absorptiometry, Photon↗
PubMed1984

Auditory brain stem potentials evoked by clicks in notch-filtered masking noise: audiological relevance.

Auditory brainstem-evoked potentials (ABEP) to clicks in notch-filtered masking noise were recorded from 10 adults with normal audiograms and from 10 adults with hearing losses. Masking noise had 0.5-octave-wide notches with central frequencies of 8 000, 2 000, 1 000, 500 and 250 Hz. For each notch frequency, decreasing-intensity series in 10-dB steps (for both the click and the noise) were derived until the detection threshold of ABEP was reached. From the detection thresholds of normal subjects, the normative detection threshold for each frequency was calculated. Deviations from the normative detection thresholds were considered ABEP estimates of hearing loss. The results of this study showed that while ABEP to clicks in notched noise were sensitive to hearing losses, correlations between audiometric hearing loss and ABEP estimates of hearing losses at specific frequencies were nonsignificant. At the present stage of the procedure, ABEP to clicks in notched noise cannot estimate hearing thresholds at specific frequencies.

Adult↗
PubMed1985

Early/middle evoked potentials to tone bursts in quiet, white noise and notched noise.

Early/middle auditory-evoked potentials were recorded on 10 normal-hearing adults using 500-, 1 000, and 2 000-Hz tone bursts having 4-ms rise-fall and 1-ms plateau times. The stimuli were presented in quiet, white noise and notched noise at 50, 40, 30, 20 and 10 dB nHL. The noises were selected to improve frequency specificity by masking those regions of the cochlea that do not correspond to the test stimulus. The recording-amplifier system had a bandpass of 55-1 500 Hz; electric activity was measured during the 25-ms post-stimulus interval. The three waves observed during this time interval (P10, N15, and P20) were labeled to reflect polarity and latency. The results revealed no differences among stimulus conditions (quiet, white noise, notched noise) in the number of identifiable responses for any wave at any intensity. Moreover, no P10, N15 or P20 latency differences were observed among conditions at 40 dB nHL and below. When 500-Hz tone bursts were presented at 50 dB nHL, however, significantly shorter response latencies were observed in quiet than when the tone bursts were mixed with white noise or notched noise. It was concluded that frequency specificity can be improved when tone bursts are mixed with notched noise or white noise. White noise is preferred, however, because it can be implemented with less complex instrumentation and calibration than notched noise.

Adult↗
PubMed1980

Meanings of a double-notch audiogram.

Audiological findings in patients with histories of noise exposure were examined. 27 patients (1.5%) were found to have audiograms with a double-notch configuration. Information from their occupational history, medical history, and audiological findings was gathered and analysed. Their results were compared with those of 50 random samples of patients without the double-notch audiogram. Analyses suggest that the low frequency notch is probably also caused by noise damage. The low incidence of double-notch audiogram reflects the small proportion of people with susceptibility to noise damage at the 500 Hz to 1 kHz region in addition to the 3 to 6 kHz region. This double-notch configuration could be exaggerated possibly by the release from inhibition by damaged hair cells.

Adult↗
PubMed1994

Effects of signal-to-noise ratio on the auditory brainstem response to tone bursts in notch noise and broadband noise.

This study investigated the effects of signal-to-noise ratio (S/N) on the latency and amplitude of the auditory brainstem response (Wave V) using 1 and 4 kHz tone bursts in notch noise and broadband noise. Normal listeners were presented with 40 dB and 80 dB nHL tone bursts in quiet and in noise at S/Ns of 10, 15, 20, and 25 dB. The latency data suggest that at low intensity levels tone bursts in quiet may be preferred to testing in noise. At moderate and high intensities, however, notch noise or broadband noise is preferred to the quiet condition because of the improved frequency specificity provided by the masking. When testing patients with flat or gradually sloping audiometric configurations at moderate to high intensities with 4 kHz, either notch noise or broadband noise with an S/N of 15 to 25 dB may be used. When presenting 1 kHz tone bursts at high intensities to patients having flat and gradually sloping losses, a notch noise at S/Ns of 10 to 25 dB is preferred to broadband noise. The use of a notch noise at 10 dB S/N may be the stimulus of choice when testing patients with moderately to steeply sloping audiometric configurations with 1 or 4 kHz tone bursts.

Acoustic Stimulation↗
PubMed1994

Intercondylar notch width and the risk for anterior cruciate ligament rupture. A case-control study in 46 female handball players.

We measured the intercondylar notch of the femur in female handball players from radiographs of 20 players with previous unilateral anterior cruciate ligament injury, and 26 controls without injury. The groups were comparable regarding age, height, weight and level of performance. Intercondylar fossa radiographs were obtained in a posteroanterior axial position. The anterior opening of the intercondylar notch was narrower in the healthy knee of the injured group compared to the controls. There was an increased risk of anterior cruciate ligament injury associated with decreasing notch opening: female handball players with 17 mm or less anterior notch width were 6 times more susceptible to anterior cruciate ligament injury compared to players with wider notch width.

Adolescent↗
PubMed1999

Notch-1 expression levels in 3T3-L1 cells influence ras signaling and transformation by oncogenic ras.

Notch proteins participate in interactions between several cell types involved on the specification of numerous cell fates during development. We previously showed that enforced downregulation of Notch-1 expression prevented adipogenesis of 3T3-L1 cells. Since adipogenesis of 3T3-L1 cells can be induced by oncogenic ras, we studied whether this was also the case in 3T3-L1 cells with decreased levels of Notch-1 expression. We found that oncogenic ras induces transformation and not differentiation of 3T3-L1 cells with diminished levels of Notch-1. This result suggests that Notch-1 is implicated in the interpretation of signals leading to activation of p21 Ras.

3T3 Cells↗
PubMedDate not supplied

Femoral Intercondylar Notch (ICN) width in Nigerians: its relationship to femur length.

We have investigated and measured the Femoral Intercondylar Notch (ICN) width in Nigerians and found the mean to be 2.24cm (22.4mm). The Intercondylar Notch (ICN) width ranged from 1.18cm (18.1mm) to 2.80cm (28.0mm). The mean value for the left femur was found to be 2.21cm and 2.27cm for the right femur. It is suggested that the difference could be the result of dominant use of one foot over the other or to occupational habit. This needs further investigation. The Femoral Intercondylar Notch (ICN) width is not related to Femur length as no relationship was found to exist between the two (p > 0.05). We conclude that since stenosed notch individuals are at high risk of Anterior Cruciate Ligament (ACL) injuries, the normal values of Intercondylar Notch (ICN) width that we have established may be utilized for practical and accurate screening of individuals who are predisposed to Anterior Cruciate Ligament (ACL) ruptures and injuries.

Adult↗
PubMed2002

Umbilical artery Doppler waveform notching: is it a marker for cord and placental abnormalities?

OBJECTIVE: To evaluate in a prospective, controlled fashion the prevalence of umbilical artery Doppler waveform notching and its association with cord and placental abnormalities. METHODS: During a 6-month period, umbilical artery velocity waveforms were prospectively obtained on 1857 pregnancies at greater than 27 weeks' gestation. All pregnant patients with the presence of a persistent fetal umbilical artery waveform notch formed the study population (cases). Control patients, matched for gestational age, with normal umbilical artery waveforms, were selected for comparison (2 controls per case). After delivery, detailed pathologic examination was performed on all umbilical cords and placentas. RESULTS: The presence of an umbilical artery waveform notch was noted in 29 (1.6%) of 1857 pregnancies. Postnatal placental evaluation showed the presence of an accessory placental lobe in 5 (17%) of 29 cases compared with 1 (1.8%) of 54 controls (P = .018). Overall, the presence of an umbilical artery waveform notch was associated with umbilical cord abnormalities in 21 (72%) of 29 cases compared with 8 (14%) of 54 controls (odds ratio, 15; 95% confidence interval, 4.4-54.4). CONCLUSIONS: Umbilical artery waveform notching appears to be a strong predictor of cord and placental abnormalities. This finding may have important clinical implications.

Adult↗
PubMed1991

Intercondylar notch measurements with special reference to anterior cruciate ligament surgery.

The femoral intercondylar notch width was measured in 93 patients with chronic anterior cruciate ligament (ACL) insufficiency (Group 1), in 62 patients with an acute tear of the ACL (Group 2), and in 38 fresh anatomic specimen knees (Group 3). In six of the specimen knees, further anatomic studies of the intercondylar notch were performed after tissue removal. The average intercondylar distance was 16.1 mm in Group 1, 18.1 mm in Group 2, and 20.4 mm in Group 3. All differences were highly significant. The intercondylar notch was wider in the posterior part and had no crossing bony ridges but had generally concave walls, which provided a functional shelf for the ACL to insert on the lateral side. Significant osteophyte formation and stenosis of the anterior outlet of the intercondylar notch occur early in the ACL-deficient knee. A narrow anterior outlet of the intercondylar notch without osteophytes was also found in knees with an acute ACL rupture. At reconstruction of the ACL, notchplasty should be performed concomitantly.

Anterior Cruciate Ligament↗
PubMedDate not supplied

Anatomical variation of the tibial plafond: the anteromedial tibial notch.

An investigation of 77 intact foot and ankle specimens (21 fresh frozen and 62 preserved) was conducted to determine normal anatomical variation of the anteromedial region of the tibial plafond. Lower extremity specimens were obtained and carefully disarticulated at the ankle joint. Care was taken to observe anterior joint capsule attachments along with plafond surface anatomy. Specimens that exhibited signs of previous trauma or significant degenerative arthritic changes were not included in the study. All of the specimens were photographed with a millimeter scale, and the photographs were later evaluated to quantify anatomical variations of the anterior medial tibial plafond. The results of this investigation demonstrated a normal variant of articular notching of the anteromedial tibial plafond. The notching appears to function as a joint capsule anchor. In the more well developed notches, a fold, apparently of synovial tissue, was found. The notching increases the surface area for capsular attachment, is variable in size, and may assist in synovial fluid movement across the joint during ambulation. This articular notching, although often encountered arthroscopically, should be considered a normal anatomical variant unless localized degenerative processes are identified.

Aged↗
PubMed1993

The middorsal notch: an intraoperative guide to overresection in secondary rhinoplasty.

A notch commonly appears at the midpoint of the nasal dorsum when the bridge has been resected beyond the ability of the soft tissues to contract. This notch, commonly seen in secondary rhinoplasty patients, occurs at the cephalic end of the supratip convexity and appears whether or not the tip has been overresected. The notch corresponds to the center of the "inverted V" deformity that signals middle vault collapse and may occur even when the middle vault has been reconstructed by spreader grafts. The middorsal notch also appears intraoperatively and therefore can guide the surgeon in determining the limits of dorsal skeletal resection. Ablation of the mid-dorsal notch by dorsal grafting is effective in both primary and secondary rhinoplasty patients.

Cartilage↗
PubMed1993

Improved prediction of preeclampsia by two-stage screening of uterine arteries using the early diastolic notch and color Doppler imaging.

OBJECTIVE: To assess the value of the early diastolic notch and color Doppler imaging of the uterine arteries at 24 weeks' gestation in a two-stage Doppler screening test for preeclampsia. METHODS: Two thousand fifty-eight unselected women had an initial screening study with continuous-wave Doppler at 18-22 weeks' gestation. Color Doppler imaging was used at 24 weeks' gestation to examine both uterine arteries in 273 women with initial abnormal results (high resistance index or diastolic notch). RESULTS: Three hundred twenty-nine women (16%) had abnormal flow velocity waveforms at the first stage and 104 (5.1%) at the second stage of Doppler screening. The presence of an early diastolic notch in the flow velocity waveform was significantly better than a high resistance index at predicting preeclampsia at both 20 and 24 weeks; the relative risk of developing significant preeclampsia for a woman with a persistent notch at 24 weeks was increased 68-fold. All women delivered before 34 weeks because of severe preeclampsia had abnormal waveforms at both stages of screening. CONCLUSION: An early diastolic notch in the flow velocity waveform is a better predictor of preeclampsia than are conventional impedance indices. Preeclampsia can be predicted effectively by two-stage Doppler screening.

Adult↗