Stepwise Advancement Research Articles

Elbow Arthroscopic Surgery Update for Sports Medicine Conditions

Elbow arthroscopic surgery can now effectively treat a variety of conditions that affect athletes. Advances in instrumentation, increased surgeon familiarity, and expanded indications have led to significant growth in elbow arthroscopic surgery in the past few decades. While positioning, portal placement, and specific instruments may vary among surgeons, anatomic considerations guide surgical approaches to minimize neurovascular compromise. Arthroscopic procedures vary in difficulty, and surgeons should follow stepwise advancement with experience. Removal of loose bodies, debridement of synovial plicae, and debridement of the extensor carpi radialis brevis for lateral epicondylitis are considered simple procedures for novice elbow arthroscopic surgeons. More advanced procedures include management of osteochondritis dissecans, valgus extension overload in the throwing athlete, and capsular release. With proper technique, a variety of athletic elbow conditions can be treated arthroscopically with predictable results and minimal morbidity.

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Introduction: Optimal nutrient delivery and the use of uniform feeding protocols have been associated with improved clinical outcomes in pediatric critical illness. We aimed to examine the prevalence of nutrition guidelines and protocols in PICUs across the world and identify variability in key practice parameters. Hypothesis: We hypothesized that feeding protocols are not routinely employed and consist of recommendations that are variable among institutions. Methods: Centers participating in a prospective nutritional study were asked to provide details of the nutrition support guidelines currently implemented in their PICU. Specific recommendations regarding feeding route, rate of advancement, contraindications, definition and management of intolerance and goals for enteral nutrition (EN) were compared between centers. Results: Of the 30 PICUs from academic centers in the international study, 9 (30%) from 3 countries reported using a nutrition guideline. EN was preferred in all the centers and recommended early in a majority of the centers, but contraindicated with ionotrope use or abdominal pathology. Uniform nutritional screening and measurement of energy expenditure were not specified in most guidelines. EN goals were volume-based and stepwise rates for advancement of EN were variable. Criteria for EN intolerance included: increased gastric residual volume (GRV) (7/9), abdominal distension (5/9), vomiting (5/9), and diarrhea (4/9). GRV threshold for stopping EN ranged from 2 to 5mL/kg or 2 to 4 hours of feed volume. A majority of the protocols defined a plan to address EN intolerance, which included reducing feed volume, post-pyloric feeding and use of prokinetics. Conclusions: Uniform nutrition guidelines were used in less than a third of all participating PICUs. A majority of the guidelines prioritize EN, soon after admission, with stepwise advancement to a specified volume goal and a plan to address intolerance. The definitions of EN intolerance are variable. Despite a lack of evidence, centers use variable GRV thresholds for stopping EN, and the indications for post-pyloric feeds and prokinetics are heterogeneous. Nutritional investigations to guide uniform evidence-based best practices in the PICU are urgently needed.

Hybrid Management of Technology for Global Co-evolution: Insight from Singapore’s Water Industry

Ensuring a sustainable water supply is crucial in all economies. Technological breakthrough has made possible the idea of using membranes to treat water. Recycling water and desalination are substitutes for the traditional water treatment process. While sea water is plentiful, the process of desalination depends largely on electricity, making the process costly. Singapore’s success in NEWater (recycled water) depended on its stepwise advancement of membrane technology with sophisticated complementary engineering systems based on advanced information technology. This advancement contributes to electricity efficiency improvement in desalination which in turn accelerates dramatic advancement of the complementary engineering systems. Synergistic effects between NEWater and desalination can be expected by constructing a hybrid management of technology fusing indigenous strength and the effect of learning leading to a new phase in Singapore’s NEWater development and also the trigger of its desalination endeavor. By means of an empirical analysis of Singapore’s pioneer challenge, this paper demonstrates the significance of this endeavor for global sustainability.

A protocol for improved stability with Herbst Appliance Treatment for adults

Objective To present a treatment protocol for improved stability with Herbst appliance treatment in Class II adult cases. Materials and methods Sixteen Class II adults were treated at the University of Hong Kong with two phase treatment. The treatment protocol which leads to good stability was presented. Results The protocol leading to stable correction of overjet, molar relationship and enhanced forward positioning of the mandible involved 12 months Herbst appliance treatment with stepwise advancement followed by fixed appliance. Conclusions The long term stability of Herbst appliance treatment is influenced by the treatment protocol employed. Based on the stability of the adult group in the present study, it is recommended to treat for 12 months in a step-wise manner for mandibular advancement with over correction.

Stepwise Advancement Herbst Appliance versus Mandibular Sagittal Split Osteotomy

To compare the treatment effects and long-term stability of the stepwise Herbst appliance and mandibular sagittal split osteotomy in skeletal Class II adult patients. Subjects comprised 16 patients in the Herbst group and another 16 patients in the surgery (mandibular sagittal split osteotomy) group. Lateral head films were taken before treatment (T0), after removal of the Herbst appliance/surgery (T1), after the fixed appliance treatment (T2), and 3 years after treatment (T3). All films were analyzed by standard cephalometrics and SO-analysis (analysis of changes in sagittal occlusion). All Herbst and surgery patients were treated successfully to Class I occlusal relationships with normal overjet and overbite. Both groups showed a significant change in mandibular base advancement (SNB, SNPg, Pg/OLp), which resulted in a decrease in the ANB angle, the Wits appraisal, and facial convexity. However, the surgery group showed larger changes in the parameters mentioned above. In terms of long-term stability, both groups achieved stable results, and no significant difference occurred over time. Stepwise advancement Herbst appliance therapy can be used to treat borderline skeletal Class II adult patients with long-term stability.

Condylar growth and mandibular positioning with stepwise vs maximum advancement

The aim of this study was to compare the effects of several Class II malocclusion treatments on condylar growth and positioning of the mandible. The material comprised series of lateral cephalograms obtained at the start, after about 6 months, and after about 12 months of treatment from 3 groups of consecutively treated patients who used a headgear-activator with stepwise mandibular advancement (HGA-S), a headgear-activator with maximum jumping of the mandible (HGA-M), and a headgear-Herbst appliance with stepwise advancement (HGH-S), respectively. Six-month growth data from matched controls were used to calculate the net treatment effects. Mandibular prognathism was enhanced after stepwise advancement but not after maximum jumping, and only during the initial phase of therapy; the effect was significantly greater for the fixed functional appliance than for the removable functional appliance. Lower-facial height was increased by the HGA-S, unchanged by the HGA-M, and restrained by the HGH-S. The low construction bite of the HGH-S meant that the extent of bone apposition on the posterior and superior parts of the condyle was similar, whereas the high construction bite of the HGA-S and the HGA-M meant that the effect on the superior part was greater, but only significantly so after stepwise advancement. The mode of jumping, the vertical opening, and whether the functional appliance is fixed or removable affect the amount and pattern of condylar growth, and the position of the mandible.

Planar frictional micro-conveyors with two degrees of freedom

The design, fabrication and operation of planar frictional micro-conveyors with two degrees of freedom (2-DOF) were investigated. The frictional micro-conveyors consisted of two parts: a driving unit and a mobile plate. The driving unit was comprised of thermal actuators which were attached to inverted feet. The plate was in constant frictional contact with the feet surfaces and by properly sequencing the motion of the feet, the plate moved with stepwise advances. Two different 2-DOF designs were constructed: an X–θ conveyor capable of linear and rotational yaw motions and an X–Y conveyor capable of planar translation. Both types of micro-conveyors were fabricated using 10 µm thick silicon-on-insulator technology. The X–θ driving unit's size was 580 × 960 µm2 and it moved a 700 × 380 µm2 plate. The X–Y driving unit's size was 720 × 720 µm2 and it moved a 530 × 530 µm2 plate. The X–θ conveyor was capable of moving the plate at a linear speed of up to 33 µm s−1 and a rotational speed of up to 7° s−1. The X–Y conveyor was capable of translating the plate at a speed of 20 µm s−1 along either axis. The conveyors were able to transport loads in excess of 850 µg.

Stepwise advancement versus maximum jumping with headgear activator

The aim of this study was to compare the effects of stepwise mandibular advancement versus maximum jumping and extended treatment versus early retention. The material was obtained prospectively and consisted of lateral cephalograms taken at the start (T0), after initial (T1), and at the end (T2) of treatment, from two groups of consecutively treated skeletal Class II patients who had undergone therapy with headgear activators. The first headgear activator group, HGA-S (n=24; mean age 11.9 +/- 1.2 years), was treated for 13 months and had 4-mm mandibular advancement every 3 months. The second headgear activator group, HGA-M (n=31; mean age 11.2 +/- 1.5 years), had maximum jumping, 6-8 mm interincisal opening, for a total of 15.4 months, and with reduced wear for the last 6.9 months. The dropout over 12 months was 41 and 46 per cent, respectively. Pre-treatment growth changes were obtained as a reference. An independent t-test was used to determine differences in baseline dentofacial morphology between the groups, a paired t-test for intra-group comparisons, and an independent t-test to evaluate differences between the groups. The results, in both groups, showed enhanced mandibular prognathism during the initial phase (T0-T1), followed by normal growth (T1-T2), and lower face height enhancement throughout treatment (T0-T2). For both groups, the mandibular plane and occlusal angle increased, possibly enhanced by 'extrusion' of the lower molars. For both groups, maxillary forward growth was restrained only during the initial phase, but the effect remained significant at T2 for the HGA-S group. In the HGA-M group, the lower incisors were protruded, while in the HGA-S group, they were unaffected. The findings indicate that both modes of mandibular jumping resulted in skeletal and dental effects. The length of active treatment seemed to be decisive in maintaining the treatment effects; stepwise advancement had less dental effects.

Mechanical strain induces Cbfa1 and type X collagen expression in mandibular condyle

Core binding factor a1 (Cbfa1) is a crucial transcriptional factor for chondrocyte maturation and osteoblast differentiation in the mandibular condyle. To quantitatively assess the amount of mRNA expression of Cbfa1 and type X collagen in response to mandibular advancement. 420, 35-day-old female Sprague-Dawley rats, were randomly divided into 20 experimental and 10 control groups corresponding to 10 time points. Experimental animals were advanced in either single or stepwise manner. Condylar cartilage was dissected under microscope and total RNA was extracted, Cbfa1 and type X collagen mRNA was quantified with real-time RT-PCR. Cbfa1 and type X collagen mRNA expression for all groups reached their peak on experimental day 21. During single advancement, Cbfa1 and type X collagen mRNA expression was consistently higher (3-fold and 2.8-fold respectively) than that of stepwise advancement (2-fold). The second advancement in the stepwise group resulted in both Cbfa1 and type X collagen level reaching another peak on day 51. Mandibular advancement promoted chondrocytes maturation and osteoblast differentiation by upregulating Cbfa1 expression. Stepwise advancement produced a higher level of Cbfa1 and type X collagen expression leading to bigger cartilage template onto which bone will form through endochondral ossification.

Neovascularization and bone formation in the condyle during stepwise mandibular advancement.

The aims of this investigation were to identify the temporal expression of vascular endothelial growth factor (VEGF) in the mandibular condyle and to correlate it with the pattern of new bone formation during stepwise mandibular advancement. Two hundred and fifty female, 35-day-old Sprague-Dawley rats were randomly divided into 10 groups, with 10 rats allocated to the single-step bite-jumping subgroup, 10 rats to the stepwise advancement subgroup and five rats to the control subgroup. In the experimental groups, the mandibles were kept in a continuous forward position. The initial stepwise advancement commenced on day 35, whereas the second advancement started on day 65. The rats were sacrificed on experimental days 3, 7, 14, 21, 30, 33, 37, 44, 51 and 60. Sections (7 microm) were cut through the condyle in the parasagittal plane and stained with anti-VEGF antibody. Each section was counter-stained with haematoxylin for observation of the cellular response. The sections were digitized and quantitatively analysed with a computer-assisted image analysing system. The results showed that the initial advancement in the stepwise group led to significantly less expression of VEGF when compared with single advancement. However, the second advancement on day 30 resulted in a significant increase in VEGF expression when compared with the one-step group and the natural growth control group. Thus, it was concluded that changes in the amplitude of mechanical loading, produced by stepwise advancement, have a significant effect on the production of VEGF by the chondrocytes. During the later stages of advancement, more VEGF and more condylar bone was produced.

Vascular endothelial growth factor expression and bone formation in posterior glenoid fossa during stepwise mandibular advancement

This study assessed the amount of vascular endothelial growth factor (VEGF) expression and related the findings to new bone formation in the posterior glenoid fossa during stepwise mandibular advancement. A total of 250 female Sprague-Dawley rats, 35 days old, were randomly divided into 10 groups, each including 5 control and 20 experimental rats. Within each group, 10 experimental rats were fitted with functional appliances with a 1-step advancement of 3.5 mm. Another 10 were fitted with stepwise appliances with an initial advancement of 2 mm and a subsequent increase to 3.5 mm on day 30. The rats in the experimental groups were killed on days 3, 7, 14, 21, 30, 33, 37, 44, 51, and 60, respectively. The matched controls were killed on the same time points. Sections (7 μm) were cut through the glenoid fossa sagittally and stained with anti-VEGF antibody. VEGF expression in the posterior glenoid fossa was evaluated with a computer-assisted image-analyzing system. Both VEGF expression and new bone formation were greater in the experimental rats than in the controls. During stepwise advancement, initial VEGF expression was less than that of 1-step advancement, but the second advancement elicited another peak on day 44. New bone formation was also less than that of 1-step advancement during early stages of stepwise advancement but then began to increase from day 37 onward. The maximum increase was observed on day 60. Stepwise advancement of the mandible delivers mechanical stimuli that produce a series of tissue responses that lead to increased vascularization and bone formation.

Correlation of replicating cells and osteogenesis in the glenoid fossa during stepwise advancement

The purposes of this study were to quantify the number of replicating mesenchymal cells and to correlate it with the amount of new bone formed in the glenoid fossa during stepwise advancement. We randomly divided 250 female Sprague-Dawley rats, 35 days old, into 10 control groups (n = 5) and 20 experimental groups (n = 10). Fifty rats from the stepwise experimental group received initial advancement of 2 mm and another 1.5 mm of advancement on day 30 by the addition of veeners. On days 3, 7, 14, 21, 30, 33, 37, 44, 51, and 60, the rats were killed. One hour before that, the rats were injected with bromodeoxyuridine (BrdU) intravenously. We cut 7-μm tissue sections through the glenoid fossa sagittally and stained them with anti-BrdU antibody to evaluate the number of replicating mesenchymal cells. During the first advancement, the number of replicating cells in the posterior region of the glenoid fossa showed a significant increase compared with natural growth, but a significant decrease compared with 1-step advancement. On the second advancement, however, an increase in the number of replicating cells was observed on day 37 with a subsequent and significant increase in bone formation on day 44. Mandibular advancement conducted in a stepwise fashion increases the number of replicating mesenchymal cells in the glenoid fossa. However, a minimum threshold of strain must first be exceeded before these mesenchymal cells can differentiate to ultimately form new bone.

Stepwise advancement using fixed functional appliances: Experimental perspective

This study was designed to identify the pattern of bone formation in thetemporomandibular joint in response to the stepwise mandibular advancement compared to single step advancement with fixed functional appliances. Two hundred fifty 35-day-old female Sprague-Dawley rats were randomly divided into 20 experimental and 10 control groups. Appliances were fitted to position the mandible forward in the experimental groups. Veneers were added to achieve movement. The rats were then sacrificed at different time points. Sections were cut and stained with periodic acid and Schiff's reagent for evaluation of new bone formation. Newly formed bone was measured by a computer-assisted image analyzing system. The results showed that, during the first advancement, bone formation in the condyle and glenoid fossa was less than that of 1-step advancement. In response to the second advancement, new bone formation was significantly higher when compared with single advancement with a maximum increase of 50% and 100% in the condyle and glenoid fossa, respectively. In conclusion, the stepwise advancement produces more skeletal effects than single advancement and a more prominent effect with stepwise advancement was found in the glenoid fossa compared with the condyle.

Osteopontin and colon cancer progression.

Human colon cancer affects nearly 150,000 patients and results in 60,000 deaths in the United States per year. Despite significant advances in the management of the colon cancer patient, little change in survival rates has been appreciated over the past 50 years. The primary cause of death relates to the development of distant metastases to organs such as the liver and lungs. Colon cancer represents an important disease to study in order to better understand tumor progression and metastasis primarily because there is almost a stepwise advancement of the disease that is marked by measurable genetic and associated phenotypic alterations. Metastasis appears to be the end product of the development of 'Herculean' cell clones capable of independent growth, invasion, adhesion, avoidance of apoptosis, and angiogenesis. Although significant progress has been made in understanding the sequential genetic events leading to the development of cancer, the precise genes and the associated molecular pathways underlying the development of metastatic potential are still poorly understood. Moreover, our enhanced genetic knowledge has had relatively little trickle down effect on our clinical management of this deadly disease. For this reason, we undertook a comprehensive study to develop a molecular encyclopedia of new tumor markers and markers of tumor progression, some of which will hopefully prove useful in the clinical management of colon cancer patients by means of their capacity to detect and predict the stage and disease burden. This review will focus on the application of gene expression profiling technology to the problem of identifying new tumor markers and progression markers, and the discovery of osteopontin as the leading candidate clinical marker derived from a screen of approximately 12,000 named genes.

Vakuumversiegelung bei Fasciitis necroticans vor Spalthautverpflanzung - nicht nur eine Ultima Ratio?

We report on a 72-year old patient who developed a large defect on his right thigh due to fasciitis necroticans. The defect extended to the muscles and could not be closed by means of a stepwise advancement of the wound edges. Split skin grafting was only successful after the wound had been conditioned with vacuum sealing for ten days.

In Praise of a Methodical Scientist

In 1910, in a historical book entitled Grosse Maenner, the great electrochemist Wilhelm Ostwald classified outstanding scientists into two groups. The brilliant, imaginative romantics made large conceptual leaps while the classicists stuck to steady, methodical, stepwise advances. But although the former usually peter out after their early successes, the latter remain creative for a lifetime. This analysis is, of course, oversimplified. But having recently compared the personalities of Francis Crick and James Watson in a review of Crick's autobiography What Mad Pursuit (C&EN, June 5, page 22), I cannot resist noting how Ostwald's typology fits the further contrast between these outstanding romantics and Arthur Kornberg. For it would be hard to find a scientist who better fitted the criteria for a classicist than Kornberg. He is passionately dedicated to solid studies with a method of proven worth, protein purification. And he is still, in his 70s, in the forefront of his field, successfully using this ...

Propagation of a westward traveling surge and the development of persistent auroral features

Imaging instrumentation on board the spacecraft Dynamics Explorer 1 (DE 1) is used to observe the large‐scale motion of a surge over 7000 km along the auroral oval from near local midnight. Average speed of the surge is 2.2 km/s. Ground‐based observations at Fort Yukon, Alaska, show the classical looped, multiple‐arc structure of a westward traveling surge as it passes overhead. Within the 6‐min temporal resolution provided with DE 1, the surge advances initially at a speed of about 8 km/s followed by a steady decline to about 1 km/s over a period of 17 min. This sequence is then repeated a second time, beginning with a significant intensification of the surge form. This intense surge activity is not accompanied by significant auroral activity near magnetic midnight. Following passage of the surge, persistent and localized bright emission regions remain along the auroral oval for several tens of minutes. Average separation distances are approximately 700 km. If these persistent features identify the sites of individual stepwise advances of the surge, the average time per advance is about 5 min.

Experimental spinal cord injury produced by slow, graded compression. Alterations of cortical and spinal evoked potentials.

✓ A new model of experimental spinal cord injury produced by slow, graded compression in cats is described. The extent of cord compression was evaluated by monitoring somatosensory evoked potentials (SEP's). The compression was exerted by means of a special screw-plate assembly with stepwise advancement of the compression plate at different time intervals and was completed when cortical SEP had disappeared. Every stage in the total course of gradual compression was expressed as a percentage of the total. Cortical and spinal SEP's were recorded at each increment. The SEP pattern was analyzed in terms of latency, amplitude, and wave form. It was noteworthy that SEP's were remarkably resistant to gradual compression. The amplitude of cortical SEP's began decreasing at a late stage of compression, usually at about 80% of total compression, and that of spinal SEP's some time earlier, at about 60% of total compression. They both then rapidly fell to zero. Cortical SEP's showed a slight increase in latency concurrent with the reduction of amplitude, while the latency of spinal SEP's was constant. Mid-thoracic SEP's showed considerable individual variation in wave form. Their changes were similar to those of cortical SEP. Thoracolumbar SEP's, recorded immediately rostral to the compression, showed little individual variation, and did not show flat recordings even with maximum compression. A small monophasic positive wave was present in all animals even after the cortical SEP's became flat. This “final potential” was assumed to be caused by electrotonic volume conduction from the activities of the dorsal white matter caudal to the compression site. The reversibility of SEP's after the release of compression was remarkable. Both cortical and spinal SEP's could show complete recovery even when histological examination demonstrated hemorrhagic necrosis. The present data show no linear correlation between SEP changes and degree of compression. There are no changes with slight or moderate degree of compression. Alterations of SEP's in slow compression models should suggest the presence of a severe degree of compression.

Application of the computer to rapid dynamic studies

Current trends in nuclear medicine to some degree, at least, reflect the level of sophistication available in the instrumentation. A technologically oriented speciality such as this might be expected to shift emphasis from time to time as stepwise advances are made in instrumentation. In its infancy, nuclear medicine concentrated on studies that could be accomplished with a single-probe system. The introduction of rectilinear scanners made imaging practical and of primary concern. Anger's gamma camera made combined static and dynamic studies possible using a single instrument--a decided advantage over previous methodology. The development of digital acquisition, processing, and display systems has had a profound effect on the recently increased emphasis on rapid dynamic studies. Computers are currently being applied to a broad range of clinical problems. Data preparation routines such as uniformity correction and data bounding often are used preliminary to more rigorous mathematical treatment. The development of reasonably low-cost, TV-type displays has greatly increased the quality of the computer display of the radionuclide imaging process.

Ultrastructural observation of 5-hydrozytryptamine-storing granules in the domestic fowl thrombocytes.

Ultrastructural observations of domestic fowl thrombocytes were made with special reference to their intracellular storage site of 5HT. Using a modified method for sampling blood and isolating thrombocytes, a characteristic structure was confirmed in the cytoplasm; the structure was highly osmiophilic, rough-surfaced and quite larger than 5HT granules observed in mammalian platelets. Disappearance of the structure, associated with a marked reduction of 5HT content, was caused by in vivo treatment with reserpine; this indicated its function to store the amine. From various morphological patterns indicative of stepwise advancement of degranulation, it was concluded that the 5HT-storing organelle is the multigranular body, which contains smooth-surfaced granules aggregated with fine filamentous structures.