Patella dislocation: an online systematic video analysis of the mechanism of injury.

BACKGROUND: The mechanism of injury (MoI) for a patellar dislocation has not been fully established. The aim of this study was to use systematic video analysis to determine the MoI of a patella dislocation. METHODS: A systematic search was conducted of three video sharing websites and three popular search engines to identify videos demonstrating a patellar dislocation. Videos were reviewed by three surgeons trained in systematic video analysis, who commented on the position of the lower limb and the situation in which the injury occurred. The results were reviewed to build a consensus of the MoI for each video. Statistical analysis was conducted for interobserver agreement (p < 0.05). RESULTS: Initial search yielded 603 videos with 13 meeting the inclusion criteria. The injuries were sustained performing a sporting activity (n = 9) or whilst dancing (n = 4). The injury was predominantly sustained during a non-contact situation (n = 10). The most common mechanism was an unbalanced individual with a flexed hip sustaining a valgus force to their flexed knee with the tibia externally rotated. CONCLUSIONS: This study provides some insight into the MoI for a patellar dislocation and the findings may assist in developing injury prevention programmes and rehabilitation protocols as well as guiding future research.

When does the patella dislocate? A systematic review of biomechanical & kinematic studies.

BACKGROUND: Patellar dislocations are a significant injury with the potential for long term problems. Little work has been done on establishing the mechanism by which this injury occurs. OBJECTIVES: To determine the mechanism of injury of a patella dislocation based on the available published literature and compare them to already proposed theories. METHODS: A systematic review of the literature was conducted following searches performed on MEDLINE, EMBASE and ProQuest from the earliest year of indexing using the following search terms in any combination: "patella", "dislocation", "mechanism of injury", "anatomy", "biomechanical" and "risk factor". A broad inclusion criteria was used that included studies that looked at patellar dislocations and instability with respect to the patellofemoral joint (PFJ) kinematics or altered kinematics of the PFJ. Studies that did not address the kinematics or biomechanics of the PFJ were excluded. Studies were appraised based on their methodology using a combination of the Critical Appraisal Skills Programme tool and the Quality Appraisal for Cadaveric Studies. RESULTS: 113 studies were identified from a search of MEDLINE, EMBASE and ProQuest databases. Following application of our inclusion criteria, a total of 23 studies were included in our review. 18 of these studies were cadaveric biomechanical studies. The remaining studies were anatomical, imaging based, and a computer simulation based study. CONCLUSIONS: These biomechanical and kinematic studies provide some evidence that a dislocation is likely to occur during early knee flexion with external rotation of the tibia and contraction of the quadriceps. There is limited evidence to support other elements of proposed mechanisms of dislocation.

Sequential gene regulatory events leading to glucocorticoid-evoked apoptosis of CEM human leukemic cells:interactions of MAPK, MYC and glucocorticoid pathways.

Gene expression responses to glucocorticoid (GC) in the hours preceding onset of apoptosis were compared in three clones of human acute lymphoblastic leukemia CEM cells. Between 2 and 20h, all three clones showed increasing numbers of responding genes. Each clone had many unique responses, but the two responsive clones showed a group of responding genes in common, different from the resistant clone. MYC levels and the balance of activities between the three major groups of MAPKs are known important regulators of glucocorticoid-driven apoptosis in several lymphoid cell systems. Common to the two sensitive clones were changed transcript levels from genes that decrease amounts or activity of anti-apoptotic ERK/MAPK1 and JNK2/MAPK9, or of genes that increase activity of pro-apoptotic p38/MAPK14. Down-regulation of MYC and several MYC-regulated genes relevant to MAPKs also occurred in both sensitive clones. Transcriptomine comparisons revealed probable NOTCH-GC crosstalk in these cells.

In CEM cells the autosomal deafness gene dfna5 is regulated by glucocorticoids and forskolin.

Certain mutations of the dfna5 gene result in a form of autosomal deafness that holds special interest because its phenotype resembles the hearing loss often seen during aging. Little is known of the function or regulation of dfna5 or its encoded protein. However dfna5 has recently been shown to be induced by p53. It also is epigenetically repressed in gastric cancer. We have discovered that dfna5 can be induced by glucocorticoids (GCs) and that this regulation is influenced by crosstalk with the protein kinase A (PKA) system. We show that GCs induce dfna5 mRNA and that its expression appears to be repressed in the basal state. Induction of dfna5 mRNA correlates with GC-dependent apoptosis of CEM cells, though dfna5 expression alone is not sufficient for apoptosis.

Identification of genes leading to glucocorticoid-induced leukemic cell death.

Glucocorticoidal steroids (GC) are capable of causing apoptotic death of many varieties of lymphoid cells; consequently, GC are used in therapy for many lymphoid malignancies. Gene transcription in the GC-treated cells is required for subsequent apoptosis, but only a few of the actual genes involved have been identified. We employed gene microarray analysis to find the network of genes involved in GC-evoked cell death, using three clones derived from the CEM lymphoid leukemia cell line. Clone C1-15 was resistant to GC-evoked apoptosis, although not necessarily to GC-induced gene transcription; the other two underwent apoptosis in the presence of GC. Clone C7-14 was subcloned from the apoptosis-sensitive parental C7 clone to establish karyotypic uniformity. The second sensitive clone, C1-6, was a spontaneous revertant from parental resistant clone C1. A period of > or = 24 h in the constant presence of receptor-occupying concentrations of synthetic GC dexamethasone (Dex) was necessary for apoptosis to begin. To identify the steps leading to this dramatic event, we identified the changes in gene expression in the 20-h period preceding the onset of overt apoptosis. Cells in the log phase of growth were treated with 10(-6) M Dex, and 2-20 h later, mRNA was prepared and analyzed using the Affymetrix HG_U95Av2 chip, containing probes for about 12,600 genes. Of these, approximately 6,000 were expressed above background. Comparisons of the basal and expressed genes in the three clones led to several conclusions: The Dex-sensitive clones shared the regulation of a limited set of genes. The apoptosis-resistant clone C1-15 showed Dex effects on a largely different set of genes. Promoter analysis of the regulated genes suggested that primary gene targets for GC often lack a classic GC response element.

Controlling the physical behavior and biological performance of liposome formulations through use of surface grafted poly(ethylene glycol).

The presence of poly(ethylene glycol) (PEG) at the surface of a liposomal carrier has been clearly shown to extend the circulation lifetime of the vehicle. To this point, the extended circulation lifetime that the polymer affords has been attributed to the reduction or prevention of protein adsorption. However, there is little evidence that the presence of PEG at the surface of a vehicle actually reduces total serum protein binding. In this review we examine all aspects of PEG in order to gain a better understanding of how the polymer fulfills its biological role. The physical and chemical properties of the polymer are explored and compared to properties of other hydrophilic polymers. An evidence based assessment of several in vitro protein binding studies as well as in vivo pharmacokinetics studies involving PEG is included. The ability of PEG to prevent the self-aggregation of liposomes is considered as a possible means by which it extends circulation longevity. Also, a "dysopsonization" phenomenon where PEG actually promotes binding of certain proteins that then mask the vehicle is discussed.

Liposomal and nonliposomal drug pharmacokinetics after administration of liposome-encapsulated vincristine and their contribution to drug tissue distribution properties.

We have determined the pharmacokinetics of liposomal vincristine, in a Lewis lung carcinoma solid tumor model in mice, with the aim of differentiating the contribution of liposomal and nonliposomal (released from liposomes) drug pools to the overall pharmacokinetic profile. Two types of liposomal formulations were used: one composed of 1,2 distearoyl-sn-glycero-3-phosphocholine/cholesterol (Chol) (55/45; mol/mol) and the other composed of sphingomyelin/cholesterol (SM/Chol; 55/45; mol/mol). Vincristine elimination from the circulation after injection of conventional, aqueous formulated vincristine (C-VINC) was characterized by a short half-life (1.36 h), low plasma area under the plasma concentration-time curve (AUC) (0.59 microg x h/ml), and large volume of distribution (145 ml). Total drug elimination from the circulation after liposomal vincristine injection using SM/Chol liposomes was characterized by a prolonged half-life (6.6 h), increased plasma AUC (213 microg x h/ml) and small volume of distribution (2.0 ml). Our results indicate that > or =98% of the total vincristine measured in the plasma of mice administered with liposomal vincristine was encapsulated within the liposomes. The systemic exposure to free drug after administration of liposomal formulations was significantly lower than that observed after the injection of C-VINC. Plasma concentrations of free drug remained between 0.025 and 0.05 microg/ml over 4 h of postinjection for both liposomal formulations. In contrast, concentrations between 0.1 and 0.35 microg/ml were observed following C-VINC administration. Free plasma drug concentrations did not correlate with vincristine tissue distribution properties following administration of liposomal vincristine formulations. Rather, accumulation of vincristine in tissues appeared to be influenced primarily by the drug retention properties of the liposome. While the reduced systemic exposure to free vincristine correlates with reduced toxicity, additional information (such as liposome drug release properties) may be necessary to correlate pharmacokinetic behavior with antitumor activity.

Toxicity and toxicokinetics of a phosphorothioate oligonucleotide against the c-myc oncogene in cynomolgus monkeys.

A 2-week toxicity and toxicokinetic study of a 15-mer phosphorothioate oligonucleotide, INX-3280, against the c-myc oncogene was performed in cynomolgus monkeys. As this oligonucleotide readily adopts an aggregate structure, a quadruplex, which may be associated with adverse physiologic effects, this study was performed using INX-3280 that had been converted to its monomeric form. Animals received intravenous (i.v.) infusions of monomeric INX-3280 three times per week for 2 weeks at doses of 3 or 15 mg/kg per administration. The monkeys were examined for clinical signs: changes in hematology, serum chemistry, coagulation, and urinalysis parameters; complement activation; macroscopic findings at necropsy; and histopathologic alterations. In addition, the toxicokinetics of INX-3280 were evaluated, using a validated HPLC assay, after the first and last (sixth) doses. No treatment-related clinical signs of any adverse effects were observed, and there were no test article-related changes in hematology, serum chemistry, or complement activation parameters. The only alteration in clinical pathology parameters was a minor (30%) prolongation of the activated partial thromboplastin time (aPTT), reflecting slight inhibition of the intrinsic coagulation pathway, which was less than that reported with other oligonucleotides given at similar doses. Treatment-related histopathologic alterations consisted of characteristic accumulation of basophilic material in the cytoplasm of tubular epithelial cells in the kidney, resident macrophages in the lymph nodes, and Kupffer cells in the liver. These changes were graded as minimal in all cases. The basophilic material is believed to reflect accumulation of the oligonucleotide or metabolites or both. The pharmacokinetic parameters of INX-3280 were identical on the first and sixth administrations and were similar to those reported for other phosphorothioate oligonucleotides. Maximum concentration (Cmax) values for INX-3280 (101-119 microg/ml) were in excess of the threshold plasma concentrations reported to trigger complement activation by phosphorothioate oligonucleotides. It is concluded that the safety profile of monomeric INX-3280 in cynomolgus monkeys is quite favorable relative to the known effects of other phosphorothioate oligonucleotides, particularly with respect to the blood level-related toxicities of this class of compounds, including complement activation and inhibition of coagulation. This study found no toxicities that were expected to be clinically significant.

Modeling women's quality of life after cardiac events.

Quality of life (QOL) is presented as a global, unidimensional, and subjective assessment of one's life. This study examined the impact of perceived health status, hope, and optimism on QOL in 93 women after suffering a cardiac event. Construct validity was examined by estimating a model where QOL was measured with four indicators, and perceived health was measured with the SF-36 Health Survey. Hope was measured with the Herth Hope Index and dispositional optimism was measured with the Life Orientation Test. The unidimensionality of QOL and its response to health status, hope, and optimism were tested. Fit indices suggested that the theoretical relations posited were compatible with the data, (chi 2(42) = 44.125, p = .382, RMSEA = .0001, GFI = .942). The model explained 66% of the variance in QOL. Modeling suggested the presence of a complex latent concept composed of hope and optimism that influenced QOL.

Antibacterial efficacy of gentamicin encapsulated in pH-sensitive liposomes against an in vivo Salmonella enterica serovar typhimurium intracellular infection model.

Encapsulation of gentamicin in liposomes can be used to achieve intracellular delivery and broaden the clinical utility of this drug. We have previously described a novel, rationally designed, pH-sensitive liposomal carrier for gentamicin that has superior in vitro efficacy against intracellular infections compared to the efficacies of both free gentamicin and non-pH-sensitive liposomal controls. This liposomal carrier demonstrated pH-sensitive fusion that was dependent on the presence of unsaturated phosphatidylethanolamine (PE) and the pH-sensitive lipid N-succinyldioleoyl-PE. The pharmacokinetics and biodistribution of the free and liposomal gentamicin were examined in mice bearing a systemic Salmonella enterica serovar Typhimurium infection. Encapsulation of gentamicin in pH-sensitive liposomes significantly increased the concentrations of the drug in plasma compared to those of free gentamicin. Furthermore, the levels of accumulation of drug in the infected liver and spleen were increased by 153- and 437-fold, respectively, as a result of liposomal encapsulation. The increased accumulation of gentamicin in the liver and spleen effected by liposomal delivery was associated with 10(4)-fold greater antibacterial activity than that associated with free gentamicin in a murine salmonellosis model. These pH-sensitive liposomal antibiotic carriers with enhanced in vitro activity could be used to improve both in vivo intracellular drug delivery and biological activity.

A progressive relaxation intervention at the worksite for African-American women.

This study examined the efficacy of a worksite-based intervention in reducing blood pressure and personal strain in African-American women. The experimental group (n = 22) was taught a 7-muscle group progressive relaxation intervention. The women, for home practice, used audiocassette tapes and diaries. The control group (n = 21) was asked to set aside 30 minutes for relaxation. All women who participated in the study were visited at the worksite weekly for eight weeks. At the conclusion of the study, the experimental group had a significantly lower mean physical strain score (23.23 [SD = 6.85] v. 27.41 [SD = 8.49]) and interpersonal strain (25.81 [SD = 6.25] v. 23.57 [SD = 6.06]); both groups had significant reductions in psychological strain scores. Although there were no significant differences in the blood pressure of the two groups at the end of the 8-week intervention (121.95 [SD = 13.28] v. 129.33 [SD = 14.30]), the mean systolic blood pressure of the treatment group did decrease from 130 mmHg to 121 mmHg. Findings from this study support the use of the work-place as a means of improving the cardiovascular health of working African-American women.

Baccalaureate nursing education and home health: a collaborative alliance.

Nursing educators are challenged to prepare practitioners to move out of acute care and perform competently in nontraditional settings. Faculty from a university college of nursing and registered nurse preceptors from 13 home health agencies formed an alliance to serve as co-educators for junior-level baccalaureate nursing students in a 35-hour, two-semester home health clinical rotation. The outcomes of this alliance were evaluated with a qualitative descriptive study that evaluated the effectiveness of the model. Content analysis of students' journal reflections revealed that the collaborative alliance in home health enabled students to integrate practice with theory and to view the new practice environment as a meaningful learning experience. Nurse preceptors serving as co-educators in the home setting were viewed as valuable role models who provided opportunities for active participation of students. In addition, this collaborative alliance enhanced students' assimilation of the principles of nontraditional practice and facilitated the personal and professional growth they needed to prepare them for nursing practice in the future.

Failure in communication. The common denominator.

Structural changes in the practice of medicine are placing pressures on physicians to alter their relations with patients. Most notable among these changes are those brought about by managed care organizations. For legal and ethical reasons, communication between the doctor and patient is essential. Furthermore, there are certain time periods in which this communication is especially important.

Preclinical and clinical experience of antisense therapy for solid tumors.

The mechanisms by which the therapeutic window and clinical utility of antisense drugs can be fully optimized are discussed. Recent preclinical and clinical efforts are focusing on defining and optimizing the combination therapy regimes in which ONs are most efficacious. However, additional research is required to define which, and how, oncogenes interact with each other and the circumstances under which synergistic therapeutic benefit might be achieved using antisense drugs. The therapeutic window of antisense drugs is also being expanded by the use of novel delivery systems, including lipid-based carriers for systemic delivery. Taken together, molecular therapeutics based on antisense technology, coupled with effective delivery systems increasing drug potency, are anticipated to substantially improve the treatment of human neoplasms.

Preclinical pharmacology, toxicology and efficacy of sphingomyelin/cholesterol liposomal vincristine for therapeutic treatment of cancer.

PURPOSE: To establish the pharmacodynamic relationships between drug biodistribution and drug toxicity/efficacy, a comprehensive preclinical evaluation of sphingomyelin/cholesterol (SM/chol) liposomal vincristine and unencapsulated vincristine in mice was undertaken. METHODS: Pharmaceutically acceptable formulations of unencapsulated vincristine and liposomal vincristine at drug/lipid ratios of 0.05 or 0.10 (wt/wt) were evaluated for toxicity, antitumor activity and pharmacokinetics following intravenous administration. RESULTS: Mice given liposomal vincristine at 2 mg/kg vincristine had concentrations of vincristine in blood and plasma at least two orders of magnitude greater then those achieved after an identical dose of unencapsulated drug. One day after administration of the liposomal vincristine, there were at least tenfold greater drug quantities, relative to unencapsulated vincristine, in the axillary lymph nodes, heart, inguinal lymph nodes, kidney, liver, skin, small intestines and spleen. Increased plasma and tissue exposure to vincristine as a result of encapsulation in SM/chol liposomes was not associated with increased drug toxicities. Treatment of the murine P388 ascitic tumor with a single intravenous dose of unencapsulated drug at 2, 3 and 4 mg/kg, initiated 1 day after tumor cell inoculation, resulted in a 33 to 38% increase in lifespan. In contrast, long-term survival rates of 50% or more were achieved in all groups treated with the SM/chol liposomal vincristine formulations at doses of 2, 3 and 4 mg/kg. At the 4 mg/kg dose, eight of ten and nine of ten animals survived past day 60 when treated with SM/chol liposomal vincristine prepared at the 0.05 and 0.1 drug/lipid ratios, respectively. CONCLUSIONS: Overall, increased and prolonged plasma concentrations of vincristine achieved by liposomal encapsulation were correlated with dramatically increased antitumor activity in comparison with the unencapsulated drug, but no correlations could be established between pharmacokinetic parameters and toxicity.

Intracellular delivery and antibacterial activity of gentamicin encapsulated in pH-sensitive liposomes.

Cell membranes are relatively impermeable to the antibiotic gentamicin, a factor that, along with the toxicity of gentamicin, precludes its use against many important intracellular bacterial infections. Liposomal encapsulation of this drug was used in order to achieve intracellular antibiotic delivery and therefore increase the drug's therapeutic activity against intracellular pathogens. Gentamicin encapsulation in several dipalmitoylphosphatidylcholine (DPPC) and pH-sensitive dioleoylphosphatidylethanolamine (DOPE)-based carrier systems was characterized. To systematically test the antibacterial efficacies of these formulations, a tissue culture assay system was developed wherein murine macrophage-like J774A.1 cells were infected with bacteria and were then treated with encapsulated drug. Of these formulations, DOPE-N-succinyl-DOPE and DOPE-N-glutaryl-DOPE (70:30;mol:mol) containing small amounts of polyethyleneglycol-ceramide showed appreciable antibacterial activities, killing greater than 75% of intracellular vacuole-resident wild-type Salmonella typhimurium compared to the level of killing of the control formulations. These formulations also efficiently eliminated intracellular infections caused by a recombinant hemolysin-expressing S. typhimurium strain and a Listeria monocytogenes strain, both of which escape the vacuole and reside in the cytoplasm. Control non-pH-sensitive liposomal formulations of gentamicin had poor antibacterial activities. A fluorescence resonance energy transfer assay indicated that the efficacious formulations undergo a pH-dependent lipid mixing and fusion event. Intracellular delivery of the fluorescent molecules encapsulated in these formulations was confirmed by confocal fluorescence microscopy and was shown to be dependent on endosomal acidification. This work shows that encapsulation of membrane-impermeative antibiotics in appropriately designed lipid-based delivery systems can enable their use in treating intracellular infections and details the development of a general assay for testing the intracellular delivery of encapsulated drug formulations.

Comparison of different hydrophobic anchors conjugated to poly(ethylene glycol): effects on the pharmacokinetics of liposomal vincristine.

Poly(ethylene glycol) (PEG) conjugated lipids have been used to increase the circulation longevity of liposomal carriers encapsulating therapeutic compounds. PEG is typically conjugated to distearoylphosphatidylethanolamine (DSPE) via a carbamate linkage that results in a net negative charge on the phosphate moiety at physiological pH. It was anticipated that the presence of this negative charge could have deleterious effects on liposome pharmacokinetic characteristics. We describe here the synthesis of a new class of neutrally charged PEG-lipid conjugates in which the PEG moiety was linked to ceramide (CER). These PEG-CER conjugates were compared with PEG-DSPE conjugates for their effects on the pharmacokinetics of liposomal vincristine. PEG-CER (78% palmitic acid, C16) and PEG-DSPE achieved comparable increases in the circulation lifetimes of sphingomyelin/cholesterol (SM/chol) liposomes. However, PEG-DSPE significantly increased the in vitro and in vivo leakage rates of vincristine from SM/chol-based liposomes compared to vincristine leakage observed when PEG-CER was used. The increase in drug leakage observed in vitro that was due to the presence of PEG-DSPE was likely due to the presence of a negative surface charge. Analysis of the electrophoretic mobilities of these formulations suggested that the negative surface charges were shielded by approx. 80% by the PEG layer extending from the membrane surface. In contrast, formulations containing PEG-CER had no surface charge and no electrophoretic mobility. A comparison of the effects of the ceramide acyl chain length (C8 through C24) on the pharmacokinetics of SM/chol/PEG-CER formulations of vincristine demonstrated that longer acyl chains on the PEG-CER were associated with longer circulation lifetimes of the liposomal carriers and, consequently, higher plasma vincristine concentrations. These data suggest that the short chain PEG-ceramides underwent rapid partitioning from the vesicles after i.v. administration, whereas the longer chain PEG-ceramides had stronger anchoring properties in the liposome bilayers and partitioned slowly from the administered vesicles. These data demonstrate the utility of ceramide-based steric stabilizing lipids as well as the potential for developing controlled release formulations by manipulating the retention of the PEG-ceramide conjugate in liposome bilayers.