A tale of a threshing machine: Images of the Voigt-Leibniz mathematical-agricultural machine at the beginning of the 18th century.

This paper examines how a certain threshing machine was developed and improved by Jobst Heinrich Voigt and Gottfried Wilhelm Leibniz between 1699 and 1700. While this machine was based on various mechanical principles and instruments, including the pinned drum mechanism first noted by Georg Philipp Harsdörffer, it was later reconceptualized as a 'mathematical' machine. I claim that such a positioning was not unique to this machine, but part of a wider movement during the 18th century that considered various artisanal instruments as mathematical, as well as agricultural and artisanal knowledge as scientific. Examining the development and subsequent reception of this machine, I show that during the first decades of the 18th century these conceptions gave rise to a double image of this machine, and hence of agricultural knowledge in general: on the one hand, this machine was considered as more efficient and productive (while still in need of improvement); on the other hand, it was viewed, either implicitly or explicitly, as something that should be studied by mathematicians, thus reflecting a changing image of mathematics.

Connexin 43 and cell culture substrate differentially regulate OCY454 osteocytic differentiation and signaling to primary bone cells.

Connexin 43 (Cx43), the predominate gap junction protein in bone, is essential for intercellular communication and skeletal homeostasis. Previous work suggests that osteocyte-specific deletion of Cx43 leads to increased bone formation and resorption; however, the cell-autonomous role of osteocytic Cx43 in promoting increased bone remodeling is unknown. Recent studies using three-dimensional (3D) culture substrates in OCY454 cells suggest that 3D cultures may offer increased bone remodeling factor expression and secretion, such as sclerostin and receptor activator of nuclear factor-κB ligand (RANKL). In this study, we compared culturing OCY454 osteocytes on 3D Alvetex scaffolds with traditional 2D tissue culture, both with [wild-type (WT)] and without Cx43 (Cx43 KO). Conditioned media from OCY454 cell cultures were used to determine soluble signaling to differentiate primary bone marrow cells into osteoblasts and osteoclasts. OCY454 cells cultured on 3D portrayed a mature osteocytic phenotype, relative to cells on 2D, shown by increased osteocytic gene expression and reduced cell proliferation. In contrast, OCY454 differentiation based on these same markers was not affected by Cx43 deficiency in 3D. Interestingly, increased sclerostin secretion was found in 3D cultured WT cells compared with that of Cx43 KO cells. Conditioned media from Cx43 KO cells promoted increased osteoblastogenesis and osteoclastogenesis, with maximal effects from 3D cultured Cx43 KO cells. These results suggest that Cx43 deficiency promotes increased bone remodeling in a cell-autonomous manner with minimal changes in osteocyte differentiation. Finally, 3D cultures appear better suited to study mechanisms from Cx43-deficient OCY454 osteocytes in vitro due to their ability to promote osteocyte differentiation, limit proliferation, and increase bone remodeling factor secretion.NEW & NOTEWORTHY 3D cell culture of OCY454 cells promoted increased differentiation compared with traditional 2D culture. Although Cx43 deficiency did not affect OCY454 differentiation, it resulted in increased signaling, promoting osteoblastogenesis and osteoclastogenesis. Our results suggest that Cx43 deficiency promotes increased bone remodeling in a cell-autonomous manner with minimal changes in osteocyte differentiation. Also, 3D cultures appear better suited to study mechanisms in Cx43-deficient OCY454 osteocytes.

Using Nursing Assessments of Mobility and Activity to Prioritize Patients Most Likely to Need Rehabilitation Services.

OBJECTIVE: To identify nursing assessments of mobility and activity associated with lower-value rehabilitation services. DESIGN: Retrospective cohort analysis of admissions from December 2016 to September 2019 SETTING: Medicine, neurology, and surgery units (n=47) at a tertiary hospital. PARTICIPANTS: We included patients with a length of stay ≥7 days on units that routinely assessed patient function (n=18,065 patients). INTERVENTIONS: Not applicable. MAIN OUTCOME: We examined the utility of nursing assessments of function to identify patients who received lower-value rehabilitation consults, defined as those who received ≤1 therapy visit. MEASURES: Patient function was assessed using 2 Activity Measure for Post-Acute Care (AM-PAC or "6 clicks") inpatient short forms: (1) basic mobility (eg, bed mobility, walking) and (2) daily activity (eg, grooming, toileting). RESULTS: Using an AM-PAC cutoff value of ≥23 correctly identified 92.5% and 98.7% of lower-value physical therapy and occupational therapy visits, respectively. In our cohort, using a cutoff value of ≥23 on the AM-PAC would have eliminated 3482 (36%) of lower-value physical therapy consults and 4076 (34%) of lower-value occupational therapy consults. CONCLUSIONS: Nursing assessment, using AM-PAC scores, can be used to help identify lower-value rehabilitation consults, which can then be reallocated to patients with greater rehabilitation needs. Based on our results, an AM-PAC cutoff value of ≥23 can be used as a guide to help prioritize patients with greater rehabilitation needs.

A unit-based, multi-center evaluation of adopting mobility measures and daily mobility goals in the hospital setting.

BACKGROUND: Promoting patient mobility helps improve patient outcomes, but mobility status is not widely tracked nor do patients have specific individualized mobility goals. PURPOSE: We evaluated nursing adoption of mobility measures and daily mobility goal achievement using the Johns Hopkins Mobility Goal Calculator (JH-MGC), a tool to guide an individualized patient mobility goal based on the level of mobility capacity. METHOD: Built on a translating research into practice framework, the Johns Hopkins Activity and Mobility Promotion (JH-AMP) program was the vehicle to promote use of the mobility measures and the JH-MGC. We evaluated a large-scale implementation effort of this program on 23 units across two medical centers. FINDINGS: Units significantly improved documentation compliance to mobility measures and achieving daily mobility goals. Units with the highest documentation compliance rates had higher rates of daily mobility goal achievement, especially for longer distance ambulation goals. DISCUSSION: The JH-AMP program improved adoption of mobility status tracking and higher nursing inpatient mobility levels.

The Johns Hopkins Activity and Mobility Promotion Program: A Framework to Increase Activity and Mobility Among Hospitalized Patients.

BACKGROUND: Greater mobility and activity among hospitalized patients has been linked to key outcomes, including decreased length of stay, increased odds of home discharge, and fewer hospital-acquired morbidities. Systematic approaches to increasing patient mobility and activity are needed to improve patient outcomes during and following hospitalization. PROBLEM: While studies have found the Johns Hopkins Activity and Mobility Promotion (JH-AMP) program improves patient mobility and associated outcomes, program details and implementation methods are not published. APPROACH: JH-AMP is a systematic approach that includes 8 steps, described in this article: (1) organizational prioritization; (2) systematic measurement and daily mobility goal; (3) barrier mitigation; (4) local interdisciplinary roles; (5) sustainable education and training; (6) workflow integration; (7) data feedback; and (8) promotion and awareness. CONCLUSIONS: Hospitals and health care systems can use this information to guide implementation of JH-AMP at their institutions.

Minimally invasive, single-stage, multilevel surgery for obstructive sleep apnoea: A systematic review and meta-analysis.

OBJECTIVES: Minimally invasive, single-staged multilevel surgery (MISS MLS) could be an optimal treatment for selected patients with obstructive sleep apnea (OSA). We aim to systematically review the efficacy of MISS MLS for patients with OSA, as well as the clinical outcomes and possible complications in OSA patients before and after MISS MLS. DESIGN AND SETTING: Systematic review and meta-analysis. Six databases were searched, and the PRISMA guideline was followed. PARTICIPANTS: Patients with OSA receiving MISS MLS. MAIN OUTCOME MEASURES: The random-effects model was adopted for the statistical synthesis. The percentage and 95% confidence interval (CI) were adopted as the effect measurements of MISS MLS for OSA. Subgroup analyses and sensitivity analyses were also performed to identify the heterogeneity among the studies. RESULTS: There were initially 154 articles for identification. Eventually, six studies with a total of 848 OSA patients completely met the inclusion criteria and were further enrolled for analysis. The pooled analysis showed statistically significant lower AHI (apnea/hypopnea index, /hr.; mean difference: -8.931, 95% CI: -11.591 to -6.271, I2 = 87.4%), ESS (mean difference: -2.947, 95% CI: -4.465 to -1.429, I2 = 94.9%), and snoring severity with 0-10 visual analog scale after surgery (mean difference: -4.966, 95% CI: -5.804 to -4.128, I2 = 96.4%). The success rate was 46% in mild/moderate OSA; however, 18% in severe OSA. There were no major complications occurred. CONCLUSIONS: The acceptable surgical outcomes, esp. in mild/moderate OSA, and rare complications are the major advantages of MISS MLS. The evidence of this study could aid the decision making in selecting suitable treatment programs for OSA patients.

Structural and functional analysis of the human cone-rod homeobox transcription factor.

The cone-rod homeobox (CRX) protein is a critical K50 homeodomain transcription factor responsible for the differentiation and maintenance of photoreceptor neurons in the vertebrate retina. Mutant alleles in the human gene encoding CRX result in a variety of distinct blinding retinopathies, including retinitis pigmentosa, cone-rod dystrophy, and Leber congenital amaurosis. Despite the success of using in vitro biochemistry, animal models, and genomics approaches to study this clinically relevant transcription factor over the past 25 years since its initial characterization, there are no high-resolution structures in the published literature for the CRX protein. In this study, we use bioinformatic approaches and small-angle X-ray scattering (SAXS) structural analysis to further understand the biochemical complexity of the human CRX homeodomain (CRX-HD). We find that the CRX-HD is a compact, globular monomer in solution that can specifically bind functional cis-regulatory elements encoded upstream of retina-specific genes. This study presents the first structural analysis of CRX, paving the way for a new approach to studying the biochemistry of this protein and its disease-causing mutant protein variants.

Sustained release varnish containing chlorhexidine for prevention of Streptococcus mutans biofilm formation on voice prosthesis surface: an in vitro study.

OBJECTIVES: In this study, we aimed to develop a novel, sustained release varnish (SRV) for voice prostheses (VP) releasing chlorhexidine (CHX), for the prevention of biofilm formation caused by the common oral bacteria Streptococcus mutans on VP surfaces. METHODS: This study was performed in an in vitro model as a step towards future in vivo trials. VPs were coated with a SRV containing CHX (SRV-CHX) or SRV alone (placebo-SRV) that were daily exposed to S. mutans. The polymeric materials of SRV were composed of ethylcellulose and PEG-400. Biofilm formation was assessed by DNA quantification (qPCR), crystal violet staining, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and kinetics experiments. RESULTS: The amount of DNA in the biofilms formed by S. mutans on VP surfaces coated once with SRV-CHX (1.024 ± 0.218 ng DNA/piece) was 58.5 ± 8.8% lower than that of placebo-SRV-coated VPs (2.465 ± 0.198 ng DNA/piece) after a 48-h exposure to S. mutans (p = 0.038). Reduced biofilm mass on SRV-CHX-coated VPs was visually confirmed by CLSM and SEM. CV staining of SRV-CHX single-coated VPs that have been exposed to S. mutans nine times showed a 98.1 ± 0.2% reduction in biofilm mass compared to placebo-SRV-coated VPs (p = 0.003). Kinetic experiments revealed that SRV-CHX triple-coated VPs could delay bacterial growth for 23 days. CONCLUSIONS: Coating VPs with SRV-CHX has an inhibitory effect on biofilm formation and prevents bacterial growth in their vicinities. This study is a proof-of-principle that paves the way for developing new clinical means for reducing both VPs' bacterial biofilm formation and device failure.

Using Systematic Functional Measurements in the Acute Hospital Setting to Combat the Immobility Harm.

Hospitalized patients often experience unnecessary immobility and inactivity leading to direct harms and poor outcomes. Despite growing evidence that early and regular mobility and activity are safe and helpful for patients in the hospital, there remains substantial room for improvement in clinical practice. Key to improvement is establishing an interdisciplinary approach to measurement and communication using a common language of function. Here we provide a framework for systematic functional measurement in the hospital. We also provide 3 specific examples of how this framework has been used to improve care: (1) targeting specialized rehabilitation providers to the patients most likely to need their services, (2) generating a daily mobility goal for all patients, and (3) identifying patients early who are likely to require postacute care.

Metacognitive control, serial position effects, and effective transfer to self-paced study.

Serial position effects involve the differential recall of information based on its temporal order at encoding. Previous research indicates that learners may be aware of these effects under certain encoding conditions, but it is unclear whether metacognitive control is sensitive to serial position effects. The current study examined whether there are serial position effects in participants' study time and whether they can learn about serial position effects under fixed encoding conditions and then transfer what they have learned to self-paced study conditions. Specifically, participants were given lists of to-be-remembered words and studied each word for a fixed duration on initial lists, but self-paced their study time on later lists. Results revealed that self-paced study times oppositely mirrored serial position effects (i.e., briefer study times in the beginning and end of each list), and serial position effects were reduced in self-paced study conditions, particularly in participants initially studying under fixed conditions before self-pacing their study time. Specifically, participants may have monitored their output and, based on observations of forgetting middle items, transferred their learning of serial position effects from prior lists. Thus, participants may use forgetting and serial position information to guide encoding, indicating that fundamental properties of the memory system can be incorporated into the processes that guide metacognitive control.

Investigation of a Large Diphtheria Outbreak and Cocirculation of Corynebacterium pseudodiphtheriticum Among Forcibly Displaced Myanmar Nationals, 2017-2019.

BACKGROUND: Diphtheria, a life-threatening respiratory disease, is caused mainly by toxin-producing strains of Corynebacterium diphtheriae, while nontoxigenic corynebacteria (eg, Corynebacterium pseudodiphtheriticum) rarely causes diphtheria-like illness. Recently, global diphtheria outbreaks have resulted from breakdown of health care infrastructures, particularly in countries experiencing political conflict. This report summarizes a laboratory and epidemiological investigation of a diphtheria outbreak among forcibly displaced Myanmar nationals in Bangladesh. METHODS: Specimens and clinical information were collected from patients presenting at diphtheria treatment centers. Swabs were tested for toxin gene (tox)-bearing C. diphtheriae by real-time polymerase chain reaction (RT-PCR) and culture. The isolation of another Corynebacterium species prompted further laboratory investigation. RESULTS: Among 382 patients, 153 (40%) tested tox positive for C. diphtheriae by RT-PCR; 31 (20%) PCR-positive swabs were culture confirmed. RT-PCR revealed 78% (298/382) of patients tested positive for C. pseudodiphtheriticum. Of patients positive for only C. diphtheriae, 63% (17/27) had severe disease compared to 55% (69/126) positive for both Corynebacterium species, and 38% (66/172) for only C. pseudodiphtheriticum. CONCLUSIONS: We report confirmation of a diphtheria outbreak and identification of a cocirculating Corynebacterium species. The high proportion of C. pseudodiphtheriticum codetection may explain why many suspected patients testing negative for C. diphtheriae presented with diphtheria-like symptoms.

Etiology of Severe Acute Respiratory Infections, Bangladesh, 2017.

In April 2017, surveillance detected a surge in severe acute respiratory infections (SARI) in Bangladesh. We collected specimens from SARI patients and asymptomatic controls for analysis with multipathogen diagnostic tests. Influenza A(H1N1)pdm09 was associated with the SARI epidemic, suggesting that introducing vaccines and empiric antiviral drugs could be beneficial.

Evaluation of health system readiness and coverage of intermittent preventive treatment of malaria in infants (IPTi) in Kambia district to inform national scale-up in Sierra Leone.

BACKGROUND: Intermittent preventive treatment of malaria in infants (IPTi) with sulfadoxine-pyrimethamine (SP) is a proven strategy to protect infants against malaria. Sierra Leone is the first country to implement IPTi nationwide. IPTi implementation was evaluated in Kambia, one of two initial pilot districts, to assess quality and coverage of IPTi services. METHODS: This mixed-methods evaluation had two phases, conducted 3 (phase 1) and 15-17 months (phase 2) after IPTi implementation. Methods included: assessments of 18 health facilities (HF), including register data abstraction (phases 1 and 2); a knowledge, attitudes and practices survey with 20 health workers (HWs) in phase 1; second-generation sequencing of SP resistance markers (pre-IPTi and phase 2); and a cluster-sample household survey among caregivers of children aged 3-15 months (phase 2). IPTi and vaccination coverage from the household survey were calculated from child health cards and maternal recall and weighted for the complex sampling design. Interrupted time series analysis using a Poisson regression model was used to assess changes in malaria cases at HF before and after IPTi implementation. RESULTS: Most HWs (19/20) interviewed had been trained on IPTi; 16/19 reported feeling well prepared to administer it. Nearly all HFs (17/18 in phase 1; 18/18 in phase 2) had SP for IPTi in stock. The proportion of parasite alleles with dhps K540E mutations increased but remained below the 50% WHO-recommended threshold for IPTi (4.1% pre-IPTi [95%CI 2-7%]; 11% post-IPTi [95%CI 8-15%], p < 0.01). From the household survey, 299/459 (67.4%) children ≥ 10 weeks old received the first dose of IPTi (versus 80.4% for second pentavalent vaccine, given simultaneously); 274/444 (62.5%) children ≥ 14 weeks old received the second IPTi dose (versus 65.4% for third pentavalent vaccine); and 83/217 (36.4%) children ≥ 9 months old received the third IPTi dose (versus 52.2% for first measles vaccine dose). HF register data indicated no change in confirmed malaria cases among infants after IPTi implementation. CONCLUSIONS: Kambia district was able to scale up IPTi swiftly and provide necessary health systems support. The gaps between IPTi and childhood vaccine coverage need to be further investigated and addressed to optimize the success of the national IPTi programme.

Three-Column Classification System for Tibial Plateau Fractures: What the Orthopedic Surgeon Wants to Know.

Recent orthopedic surgical literature emphasizes a three-column approach to understand and guide the treatment of tibial plateau fractures. This three-column classification system published in 2010 relies on preoperative CT images to depict injuries to the medial, lateral, and posterior columns of the tibial plateau and improves surgical outcomes in complex tibial plateau fractures with coronal fracture planes and posterior plateau fracture fragments requiring dorsal plating. Tibial plateau fracture classification systems traditionally used by radiologists and orthopedic surgeons, including the Schatzker and the Arbeitsgemeinschaft für Osteosynthesefragen-Orthopedic Trauma Association (AO-OTA) classification systems, rely on findings at anteroposterior radiography and lack the terminology to accurately characterize fractures in the coronal plane involving the posterior tibial plateau. Incorporating elements from the contemporary three-column classification system into radiology reports will enhance radiologists' descriptions of these injuries. It is essential for radiologists to understand the role of clinical assessment and the pertinent imaging findings taken into consideration by orthopedic surgeons in their management of these injuries. This understanding includes familiarity with injury patterns and how they relate to mechanism of injury, patient demographics, and underlying pertinent comorbidities. Evaluating findings on initial radiographs is the basis of tibial plateau fracture diagnosis. Additional information provided by preoperative cross-sectional imaging, including two-dimensional and three-dimensional CT and MRI in specific circumstances, aids in the identification of specific soft-tissue injuries and fracture morphologies that influence surgical management. These specific fracture morphologies and soft-tissue injuries should be identified and communicated to orthopedic surgeons for optimal patient management. Online DICOM image stacks are available for this article. ©RSNA, 2020.

Genetic variability affects the response of skeletal muscle to disuse.

OBJECTIVE: To examine whether genetic variability plays a role in skeletal muscle response to disuse. METHODS: We examined skeletal muscle response to disuse in five different strains of mice: CAST/EiJ, NOD/ShiLtJ, NZO/HILtJ, 129S1/SvImJ and A/J. Mice had one limb immobilized by a cast for three weeks. RESULTS: Response to immobilization was dependent on the strain of mice. Skeletal muscle mass/body weight was decreased by immobilization in all strains except 1291/SvImJ. Immobilization decreased absolute skeletal muscle mass in quadriceps and gastrocnemius in NOD/ShiltJ and NZO/HILtJ mice. Three weeks of immobilization resulted in an increase in quadriceps levels of atrogenes in CAST/EiJ. Immobilization resulted in an increase in quadriceps and gastrocnemius levels of Myh4 in CAST/EiJ. A similar trend was observed for Myh7 in gastrocnemius muscle. Immobilization resulted in a decrease of the p-p70S6K1/total p706SK1 ratio in quadriceps of NOD/ShiLtJ mice and the gastrocnemius of A/J mice. Immobilization did not affect the p-4EBP1/total 4EBP1 ratio in quadriceps of any of the strains examined. However, the p-4EBP1/total 4EBP1 ratio in gastrocnemius was greater in immobilized, relative to control, limbs in CAST/EiJ mice. CONCLUSION: Genetic variability affects the response of skeletal muscle to disuse.

Voice Prosthesis Coated with Sustained Release Varnish Containing Clotrimazole Shows Long-Term Protection against Candida albicans: An In Vitro Study.

Fungal biofilm formation on voice prosthesis (VP) is a major health problem that requires repeated replacement of the prosthesis. Candida albicans is one of the pathogens that frequently inhabits the VP. We proposed that coating VPs with sustained-release varnish (SRV) containing clotrimazole (CTZ) might prevent fungal biofilm formation. The long-term antifungal activities of SRV-CTZ- versus SRV-placebo-coated VPs was tested daily by measuring the inhibition zone of C. albicans seeded on agar plates or by measuring the fungal viability of C. albicans in suspension. The extent of biofilm formation on coated VPs was analyzed by confocal microscopy and scanning electron microscopy. We observed that SRV-CTZ-coated VPs formed a significant bacterial inhibition zone around the VPs and prevented the growth of C. albicans in suspension during the entire testing period of 60 days. Fungal biofilms were formed on placebo-coated VPs, while no significant biofilms were observed on SRV-CTZ-coated VPs. HPLC analysis shows that CTZ is continuously released during the whole test period of 60 days at a concentration above the minimal fungistatic concentration. In conclusion, coating VPs with an SRV-CTZ film is a potential effective method for prevention of fungal infections and biofilm formation on VPs.

Effect of epigallocatechin gallate on dental biofilm of Streptococcus mutans: An in vitro study.

BACKGROUND: Streptococcus mutans (S. mutans) plays a major role in the formation of dental caries. The aim of this study was to examine the effect of the green tea polyphenol, epigallocatechin gallate (EGCG), on biofilm formation of S. mutans. METHODS: Following exposure to increasing concentrations of EGCG, the planktonic growth was measured by optical density and the biofilm biomass was quantified by crystal violet staining. Exopolysaccharides (EPS) production was visualized by confocal scanning laser microscopy, and the bacterial DNA content was determined by quantitative polymerase chain reaction (qPCR). Gene expression of selected genes was analyzed by real time (RT)-qPCR and membrane potential was examined by flow cytometry. RESULTS: We observed that EGCG inhibited in a dose-dependent manner both the planktonic growth and the biofilm formation of S. mutans. Significant reduction of S. mutans biofilm formation, DNA content, and EPS production was observed at 2.2-4.4 mg/ml EGCG. EGCG reduced the expression of gtfB, gtfC and ftf genes involved in EPS production, and the nox and sodA genes involved in the protection against oxidative stress. Moreover, EGCG caused an immediate change in membrane potential. CONCLUSIONS: EGCG, a natural polyphenol, has a significant inhibitory effect on S. mutans dental biofilm formation and EPS production, and thus might be a potential drug in preventing dental caries.

Psychometric Testing of the Activity Measure for Post-Acute Care (AM-PAC) in the Pediatric Acute Care Setting.

PURPOSE: To determine interrater reliability and construct validity of the Activity Measure for Post-Acute Care (AM-PAC) Inpatient "6-clicks" Short Forms for children in acute care. METHODS: Eight physical therapists (PTs) scored the AM-PAC Basic Mobility, 30-second walk test (30SWT), and Timed Up and Go (TUG) for 54 patients (4-17 years); 6 occupational therapists (OTs) scored the AM-PAC Daily Activity and handgrip dynamometry for 50 patients (5-17 years). Correlations between the AM-PAC Basic Mobility, 30SWT, and TUG and between the Daily Activity AM-PAC and handgrip dynamometry were calculated for evidence of construct validity. RESULTS: Interrater reliability for the AM-PAC was excellent for PTs and OTs. Validity was strong to moderate for Basic Mobility when compared with the 30SWT and TUG. Daily Activity had weak correlation with mean left handgrip strength and no correlation with mean right handgrip strength. CONCLUSIONS: AM-PAC Short Forms have acceptable psychometrics for use among children in acute care.

Quantitative Variable Assessment of Patellar Instability: An MRI-Based Study.

OBJECTIVE. The purpose of this study was to investigate the reproducibility of three quantitative MRI parameters associated with patellar instability and to determine whether they measure anatomic predisposition to patellar instability individually or in combination with the other parameters. MATERIALS AND METHODS. In this retrospective study, 100 patients diagnosed with a patellar dislocation injury and 100 age- and sex-matched control patients were examined using MRI. The distance between the tibial tubercle and posterior cruciate ligament (TT-PCL), distance between the tibial tubercle and trochlear groove (TT-TG), and TG depth (trochlear dysplasia) were measured independently by three fellowship-trained musculoskeletal radiologists. Intraclass correlation coefficient (ICC) was used to assess intraobserver and interobserver reliability. The parameters in both groups were tested for interdependence on each other and were compared for prevalence and association with patellar instability. RESULTS. All three parameters showed almost perfect intraobserver (TT-PCL ICC, ≥ 0.88; TT-TG ICC, 0.96; trochlear dysplasia ICC, ≥ 0.92) and interobserver (TT-PCL ICC, 0.82; TT-TG ICC, 0.94; trochlear dysplasia ICC, 0.91) reliability and were significantly more common in the patellar instability group. Trochlear dysplasia had the highest association with patellar instability, both as a unique parameter and in pairwise combination with an abnormal TT-TG. Optimal cutoff thresholds for normal TT-TG and TT-PCL were 15.00 mm or less and 21.30 mm or less, respectively. The optimal normal cutoff threshold for evaluating trochlear dysplasia via trochlear depth was 4.95 mm or more. CONCLUSION. Patellar instability is multifactorial. Highly reproducible parameters derived from MRI reveal both unique and overlapping anatomic predispositions, and considering all parameters together may help individualize patient management when selecting orthopedic procedures.

Sustained-release delivery of antimicrobial drugs for the treatment of periodontal diseases: Fantasy or already reality?

Periodontal diseases are prevalent in humans. Conventional means of combating these diseases involve basic oral hygiene, mostly toothbrushing, use of mouthwashes, and flossing. Supplementary means of treatment, either clinical or pharmaceutical, are often necessary. The use of sustained-release delivery systems, applied locally to the periodontal pocket, seems to be one feasible approach: local sustained-release delivery of antibacterial agents to treat periodontal diseases is conceivable. The use of local (intrapocket) sustained-release delivery systems has numerous clinical, pharmacologic, and toxicologic advantages over conventional treatments for periodontal diseases. Sustained-release technology has been proven to be effective over the last few decades. Films, gels, and fibers are the three main classical intrapocket pharmaceutical delivery systems. Research today is more focused on improving drug delivery, and less on introducing new drugs. New approaches, eg, those making use of nanotechnology, are emerging for local drug-delivery systems. The local sustained-release delivery system concept is innovative and a few products are already commercially available.