-
Developmental Cell Apr 2022During embryonic development, digits gradually emerge in a periodic pattern. Although genetic evidence indicates that digit formation results from a self-organizing...
During embryonic development, digits gradually emerge in a periodic pattern. Although genetic evidence indicates that digit formation results from a self-organizing process, the underlying mechanisms are still unclear. Here, we find that convergent-extension tissue flows driven by active stresses underlie digit formation. These active stresses simultaneously shape cartilage condensations and lead to the emergence of a compressive stress region that promotes high activin/p-SMAD/SOX9 expression, thereby defining digit-organizing centers via a mechanical feedback. In Wnt5a mutants, such mechanical feedback is disrupted due to the loss of active stresses, organizing centers do not emerge, and digit formation is precluded. Thus, digit emergence does not result solely from molecular interactions, as was previously thought, but requires a mechanical feedback that ensures continuous coupling between phalanx specification and elongation. Our work, which links mechanical and molecular signals, provides a mechanistic context for the emergence of organizing centers that may underlie various developmental processes.
Topics: Activins; Chondrogenesis; Extremities; Feedback; Gene Expression Regulation, Developmental; Morphogenesis
PubMed: 35413235
DOI: 10.1016/j.devcel.2022.03.004 -
Scientific Reports May 2021Hands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures,...
Hands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures, but there is a lack of studies in prepubertal cohorts. The available literature reports more heterogeneous findings in prepubertal compared to postpubertal cohorts. The comparability of the available studies is further limited by the study design and different measurement techniques. The present study compared the reliability and sex differences of available hand and digit measures, namely digit lengths of 2D, 3D, 4D, 5D, digit ratios 2D:4D, 2D:5D, 3D:4D, 3D:5D, 4D:5D, relative digit lengths rel2, rel3, rel4, rel5, directional asymmetry of right and left 2D:4D (D), hand width, length, and index of 399 male and 364 female 6-month-old German infants within one study using only indirect and computer-assisted measurements. The inter-examiner reliability was excellent while the test-retest reliability of hand scans was only moderate to high. Boys exhibited longer digits as well as wider and longer hands than girls, but smaller digit ratios, with ratios comprising the fifth digit revealing the largest effect sizes. Other hand and digit ratios revealed sex differences to some extent. The findings promote the assumption of sexual dimorphic hand and digit measures. However, by comparing the results of the available literature, there remains an uncertainty regarding the underlying hypothesis. Specifically in prepubertal cohorts, i.e. before the influence of fluctuating hormones, significant effects should be expected. It seems like other factors than the influence of prenatal androgens contribute to the sexual dimorphism in hand and digit lengths.
Topics: Female; Fingers; Functional Laterality; Humans; Infant; Male; Reproducibility of Results; Sex Characteristics
PubMed: 34040007
DOI: 10.1038/s41598-021-89590-w -
The Journal of Hand Surgery Aug 2020Replant survival rates have reportedly declined over the past decade. Although this problem is multifactorial, 1 potential solution may include the development of a...
PURPOSE
Replant survival rates have reportedly declined over the past decade. Although this problem is multifactorial, 1 potential solution may include the development of a relevant teaching model. The development of an in vivo animal model that can be used for surgical training could enhance surgeon and resident experience and potentially improve outcomes. Here, we present a novel training model for digit replantation using turkey digits.
METHODS
Six mature male Bourbon Red turkeys were included in this study. With the animal under general anesthesia, the third digit on either the left or the right foot was randomly selected and amputated. The medial and lateral digital neurovascular bundles were dissected on both sides and the digit was replanted. Perfusion was confirmed prior to skin closure. The foot was casted prior to extubating the turkeys. Turkeys were then placed in a non-weight-bearing sling. Digit status was evaluated twice daily.
RESULTS
All 6 replanted digits were viable immediately after surgery and for at least 24 hours after surgery. The average digit survival was 6 days with a maximum survival of 15 days. All digits were eventually lost owing to a variety of reasons including infection and arterial thrombosis.
CONCLUSIONS
The turkey digit proved to be a successful short-term animal training model for digit replantation. Future studies are needed to determine optimum standard surgical procedure and postoperative care to maximize the educational benefits of this training model.
CLINICAL RELEVANCE
To establish an animal model that can simulate digital replantation.
Topics: Amputation, Traumatic; Animals; Finger Injuries; Fingers; Male; Replantation; Retrospective Studies; Turkeys
PubMed: 32245713
DOI: 10.1016/j.jhsa.2020.02.001 -
Computational Intelligence and... 2022Classification of isolated digits is the basic challenge for many speech classification systems. While a lot of work has been carried out on spoken languages, only...
Classification of isolated digits is the basic challenge for many speech classification systems. While a lot of work has been carried out on spoken languages, only limited research work on spoken English digit data has been reported in the literature. The paper proposes an intelligent-based system based on deep feedforward neural network (DFNN) with hyperparameter optimization techniques, an ensemble method; random forest (RF), and a regression method; gradient boosting (GB) for the classification of spoken digit data. The paper investigates different machine learning (ML) algorithms to determine the best method for the classification of spoken English digit data. The DFNN classifier outperformed the RF and GB classifiers on the public benchmark spoken English digit data and achieved 99.65% validation accuracy. The outcome of the proposed model performs better compared to existing models with only traditional classifiers.
Topics: Algorithms; Deep Learning; Language; Machine Learning; Neural Networks, Computer
PubMed: 36211015
DOI: 10.1155/2022/3364141 -
NeuroImage Jan 2019The dominant model of number processing suggests the existence of a Number Form Area (NFA) in the inferior temporal gyrus (ITG) that supports the processing of Arabic...
The dominant model of number processing suggests the existence of a Number Form Area (NFA) in the inferior temporal gyrus (ITG) that supports the processing of Arabic digits as visual symbols of number. However, studies have produced inconsistent evidence for the presence and laterality of digit-specific ITG activity. Furthermore, whether any such activity relates to mathematical competence is unknown. This study investigated these two issues using functional magnetic resonance imaging. Thirty-two adults performed digit and letter detection tasks and reading and mathematics tests. During digit detection, participants determined whether digits were present in a string of letters (e.g., AH3NR versus AHTNR). During letter detection, participants determined whether letters were present in a string of digits (e.g., 93R78 versus 93478). Results showed four clusters in frontal, occipital, and temporal regions for digit detection, including a left ITG cluster. Five clusters in frontal, parietal, occipital, and temporal regions were associated with letter detection, including a left ITG cluster. Digit and letter-related ITG clusters were spatially distinct; however, a direct contrast of digit and letter processing did not reveal greater activity in the left ITG for digit detection. Whole brain correlations showed greater digit-related activity in the right ITG for participants with higher calculation skills, but there was no correlation between letter activity and calculation skills. Together, our results suggest functional localization, but not specialization, for digits in the left ITG and provide the first evidence of a relationship between calculation skills and digit processing in the right ITG.
Topics: Adolescent; Brain Mapping; Female; Functional Laterality; Humans; Magnetic Resonance Imaging; Male; Mathematical Concepts; Pattern Recognition, Visual; Temporal Lobe; Young Adult
PubMed: 30342974
DOI: 10.1016/j.neuroimage.2018.10.047 -
The Journal of Hand Surgery Sep 2018Camptodactyly of the lesser digits is commonly seen in patients with arthrogryposis. The flexed posture of the digit can be functionally limiting and necessitate... (Review)
Review
Camptodactyly of the lesser digits is commonly seen in patients with arthrogryposis. The flexed posture of the digit can be functionally limiting and necessitate surgical treatment to improve grasp function. In digits with normal bony anatomy, a lateral stiletto-shaped transposition flap combined with flexor digitorum superficialis tendon release, can improve finger deformity and function.
Topics: Arthrogryposis; Child; Contraindications, Procedure; Female; Fingers; Hand Strength; Humans; Orthopedic Procedures; Postoperative Care; Surgical Flaps; Tendons
PubMed: 29691077
DOI: 10.1016/j.jhsa.2018.03.023 -
The Journal of Hand Surgery Aug 2023Variations in the description of the flexor pulley system exist, particularly in whether the A1 and A2 pulleys represent discrete or confluent entities. This has...
PURPOSE
Variations in the description of the flexor pulley system exist, particularly in whether the A1 and A2 pulleys represent discrete or confluent entities. This has potentially important clinical relevance at the time of A1 pulley release for symptomatic trigger finger, given the goal of adequate release without overrelease. The purpose of this study was to determine the relative prevalence of confluent A1 pulleys on a digit-by-digit basis employing 2.5× loupes alone, thereby simulating a clinical surgical environment.
METHODS
Cadaveric anatomic specimens underwent flexor pulley system dissection under 2.5× loupe magnification by 2 hand surgeons. The presence of pulley confluence and length (measured from the proximal aspect to the distal aspect) was recorded and compared on a digit-to-digit basis.
RESULTS
Forty-five digits, comprising 9 adult forearm or hand specimens (5 right and 4 left) obtained from 6 donors (4 men and 2 women, age: 67 ± 8 years), were dissected. A total of 19 confluent A1 pulleys were encountered, with notable digit-by-digit variation in the prevalence of confluent pulleys. There were 0 confluent pulleys observed in the thumb, compared with 6 confluent pulleys observed in the middle finger. The average overall A1 pulley length was 5.0 ± 1.5 mm, with a similar pulley length observed between the digits.
CONCLUSIONS
A1 pulley confluence varies on a digit-to-digit basis, with no observed confluence in the thumb and the most common confluence observed in the middle finger.
CLINICAL RELEVANCE
In the setting of intraoperatively observed pulley confluence, we suggest pulley release under traction in order to develop the plane between the A1 and A2 pulleys and, thus, confirm the complete and isolated release of the A1 pulley.
Topics: Male; Adult; Humans; Female; Middle Aged; Aged; Tendons; Hand; Fingers; Thumb; Trigger Finger Disorder
PubMed: 35459577
DOI: 10.1016/j.jhsa.2022.02.011 -
Cureus Sep 2022Super digits are a rare hand malformation, first described by Virchel Wood. Surgical intervention to try to make two fingers out of a super digit has been discouraged....
Super digits are a rare hand malformation, first described by Virchel Wood. Surgical intervention to try to make two fingers out of a super digit has been discouraged. Here, we present a variant of a super digit type IC2 and propose a revision of the characteristics in each super digit subtype. In our view, this adjustment in Wood's original description could facilitate the identification of super digits, which are a contraindication to syndactyly release.
PubMed: 36199652
DOI: 10.7759/cureus.28678 -
Neuropsychology Nov 2014Digit and dot number-matching stimuli were used to replicate findings reported for younger adults by Patel and Hellige (2007) and to explore whether performance would...
Digit and dot number-matching stimuli were used to replicate findings reported for younger adults by Patel and Hellige (2007) and to explore whether performance would differ for younger versus older participants. Participants were to make numerical matches of digits only, dots only, and digits and dots mixed conditions to determine whether reaction time (RT), percentage error, and efficiency scores that combine latency and accuracy for match trials were better on within- versus across-hemisphere trials. Sixty-six younger and 42 older participants were screened with the Mini-Mental State Examination (MMSE) and the Geriatric Depression Scale. They performed the three experimental conditions and were assessed with Digit Span Forward and Backward subscales from the Wechsler Adult Intelligence Scale-III. Results for younger adults demonstrated a within-hemisphere advantage for the Digits and Mixed conditions and an across-hemisphere advantage for the Dots condition, consistent with previous literature. Older participants showed a stronger within-hemisphere advantage for the Digits condition compared with younger participants and no advantage for within- or across-hemisphere processing for the Mixed condition when RT was considered, but they performed similarly to younger adults when efficiency scores were used and showed a relative across-hemisphere advantage for the Dots condition. Although RT suggests age-related differences in how information is distributed across the hemispheres of the brain, more comprehensive efficiency scores indicate that younger and older adults appear to use similar strategies in the coordination of interhemispheric transfer of information. MMSE scores regardless of age were related to type of task but not to across- versus within-hemisphere performance.
Topics: Adult; Aged; Aged, 80 and over; Brain; Female; Humans; Male; Neuropsychological Tests; Reaction Time; Task Performance and Analysis; Wechsler Scales
PubMed: 25133318
DOI: 10.1037/neu0000125 -
The Journal of Hand Surgery Mar 2023The purpose of this study was to determine if the use of postoperative therapeutic dose intravenous heparin (POTDIVH) was indicated in digital replantation and...
PURPOSE
The purpose of this study was to determine if the use of postoperative therapeutic dose intravenous heparin (POTDIVH) was indicated in digital replantation and revascularization by assessing digit survival and complications associated with heparin.
METHODS
All patients with amputation distal to the carpal tunnel treated at our center from 2004 to 2020 were included for chart review. Digit survival and complication rates were compared between patients who received POTDIVH (group A) and those who did not (group B). Logistic regression analysis and subgroup analysis were conducted.
RESULTS
A total of 795 patients (1,155 digits) were included in this study (248 patients/374 digits in group A and 547 patients/781 digits in group B). The overall revascularization and replantation success rate was 79.9% in the POTDIVH group and 92.8% in the non-POTDIVH group. In our retrospective regression and subgroup analyses, group A demonstrated increased odds of failure compared with group B and was associated with increased bleeding-related complications. Subgroup analyses stratified by the mechanism of injury and vein grafting also showed a significantly decreased survival in the POTDIVH group.
CONCLUSIONS
Our retrospective data seem to indicate that heparin in digit replantation and revascularization appears to have no benefit on digit survival across all subgroups, including crush and avulsion injuries, and is associated with a significantly increased rate of complications.
TYPE OF STUDY/LEVEL OF EVIDENCE
Therapeutic IV.
Topics: Humans; Retrospective Studies; Amputation, Traumatic; Finger Injuries; Heparin; Replantation; Fingers
PubMed: 36266149
DOI: 10.1016/j.jhsa.2022.08.011