Amyloid beta 42 alters cardiac metabolism and impairs cardiac function in male mice with obesity

There are epidemiological associations between obesity and type 2 diabetes, cardiovascular disease and Alzheimer's disease. The role of amyloid beta 42 (Aβ42) in these diverse chronic diseases is obscure. Here we show that adipose tissue releases Aβ42, which is increased from adipose tissue of male mice with obesity and is associated with higher plasma Aβ42. Increasing circulating Aβ42 levels in male mice without obesity has no effect on systemic glucose homeostasis but has obesity-like effects on the heart, including reduced cardiac glucose clearance and impaired cardiac function. The closely related Aβ40 isoform does not have these same effects on the heart. Administration of an Aβ-neutralising antibody prevents obesity-induced cardiac dysfunction and hypertrophy. Furthermore, Aβ-neutralising antibody administration in established obesity prevents further deterioration of cardiac function. Multi-contrast transcriptomic analyses reveal that Aβ42 impacts pathways of mitochondrial metabolism and exposure of cardiomyocytes to Aβ42 inhibits mitochondrial complex I. These data reveal a role for systemic Aβ42 in the development of cardiac disease in obesity and suggest that therapeutics designed for Alzheimer's disease could be effective in combating obesity-induced heart failure.

Class IIa HDACs inhibit cell death pathways and protect muscle integrity in response to lipotoxicity

Lipotoxicity, the accumulation of lipids in non-adipose tissues, alters the metabolic transcriptome and mitochondrial metabolism in skeletal muscle. The mechanisms involved remain poorly understood. Here we show that lipotoxicity increased histone deacetylase 4 (HDAC4) and histone deacetylase 5 (HDAC5), which reduced the expression of metabolic genes and oxidative metabolism in skeletal muscle, resulting in increased non-oxidative glucose metabolism. This metabolic reprogramming was also associated with impaired apoptosis and ferroptosis responses, and preserved muscle cell viability in response to lipotoxicity. Mechanistically, increased HDAC4 and 5 decreased acetylation of p53 at K120, a modification required for transcriptional activation of apoptosis. Redox drivers of ferroptosis derived from oxidative metabolism were also reduced. The relevance of this pathway was demonstrated by overexpression of loss-of-function HDAC4 and HDAC5 mutants in skeletal muscle of obese db/db mice, which enhanced oxidative metabolic capacity, increased apoptosis and ferroptosis and reduced muscle mass. This study identifies HDAC4 and HDAC5 as repressors of skeletal muscle oxidative metabolism, which is linked to inhibition of cell death pathways and preservation of muscle integrity in response to lipotoxicity.

Effects of psychoactive drugs on cellular bioenergetic pathways

OBJECTIVES

To investigate the actions of lithium, valproate, lamotrigine and quetiapine on bioenergetic pathways in cultured NT2-N neuronal-like cells and C8-B4 microglial cells.

METHODS

NT2-N and C8-B4 cells were cultured and treated with lithium (2.5 mM), valproate (0.5 mM), quetiapine (0.05 mM) or lamotrigine (0.05 mM) for 24 hours. Gene expression and the mitochondrial bioenergetic profile were measured in both cell lines.

RESULTS

In NT2-N cells, valproate increased oxidative phosphorylation (OXPHOS) gene expression, mitochondrial uncoupling and maximal respiratory capacity, while quetiapine decreased OXPHOS gene expression and respiration linked to ATP turnover, as well as decreasing the expression of genes in the citric acid cycle. Lamotrigine decreased OXPHOS gene expression but had no effect on respiration, while lithium reduced the expression of genes in the citric acid cycle. In C8-B4 cells, valproate and lithium increased OXPHOS gene expression, and valproate increased basal respiratory rate and maximal and spare respiratory capacities. In contrast, quetiapine significantly reduced basal respiratory rate and maximal and spare respiratory capacities.

CONCLUSIONS

Overall our data suggest that some drugs used to treat neuropsychiatric and affective disorders have actions on a range of cellular bioenergetic processes, which could impact their effects in patients.

1-Methyl-1H-pyrazole-5-carboxamide Derivatives Exhibit Unexpected Acute Mammalian Toxicity

A series of 1-methyl-1H-pyrazole-5-carboxamides were synthesized as potent inhibitors of the parasitic nematode of sheep, Haemonchus contortus. These compounds did not show overt cytotoxicity to a range of mammalian cell lines under standard in vitro culture conditions, had high selectivity indices, and were progressed to an acute toxicity study in a rodent model. Strikingly, acute toxicity was observed in mice. Experiments measuring cellular respiration showed a dose-dependent inhibition of mitochondrial respiration. Under these conditions, potent cytotoxicity was observed for these compounds in rat hepatocytes suggesting that the potent acute mammalian toxicity of this chemotype is most likely associated with respiratory inhibition. In contrast, parasite toxicity was not correlated to acute toxicity or cytotoxicity in respiring cells. This paper highlights the importance of identifying an appropriate in vitro predictor of in vivo toxicity early on in the drug discovery pipeline, in particular assessment for in vitro mitochondrial toxicity.

Loss of protein kinase D activity demonstrates redundancy in cardiac glucose metabolism and preserves cardiac function in obesity

Objective

Protein kinase D (PKD) signaling has been implicated in stress-induced cardiac remodeling and function as well as metabolic processes including contraction-mediated cardiac glucose uptake. PKD has recently emerged as a nutrient-sensing kinase that is activated in high-lipid environments, such as in obesity. However, the role of PKD signaling in cardiac glucose metabolism and cardiac function in both normal and obese conditions remains unknown.

Methods

A cardiac-specific and inducible dominant negative (DN) PKD mouse model was developed. Echocardiography was used to assess cardiac function, while metabolic phenotyping was performed, including stable isotope metabolomics on cardiac tissue in mice fed either regular chow or a high-fat diet (43% calories from fat).

Results

Cardiac PKD activity declined by ∼90% following DN PKD induction in adult mice. The mice had diminished basal cardiac glucose clearance, suggesting impaired contraction-mediated glucose uptake, but normal cardiac function. In obesity studies, systolic function indices were reduced in control mice, but not in cardiac DN PKD mice. Using targeted stable isotope metabolomic analyses, no differences in glucose flux through glycolysis or the TCA cycle were observed between groups.

Conclusions

The data show that PKD contributes to cardiac dysfunction in obesity and highlight the redundancy in cardiac glucose metabolism that maintains cardiac glucose flux in vivo. The data suggest that impairments in contraction-mediated glucose uptake are unlikely to drive cardiac dysfunction in both normal and metabolic disease states.

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Cardiac protein kinase D (PKD) is required for contraction-mediated glucose uptake.

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PKD is not essential for normal cardiac function.

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Loss of PKD activity does not alter cardiac glucose flux in normal or obese mice.

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Loss of cardiac PKD activity preserves cardiac function in obesity.

Integrated analysis of a compendium of RNA-Seq datasets for splicing factors

A vast amount of public RNA-sequencing datasets have been generated and used widely to study transcriptome mechanisms. These data offer precious opportunity for advancing biological research in transcriptome studies such as alternative splicing. We report the first large-scale integrated analysis of RNA-Seq data of splicing factors for systematically identifying key factors in diseases and biological processes. We analyzed 1,321 RNA-Seq libraries of various mouse tissues and cell lines, comprising more than 6.6 TB sequences from 75 independent studies that experimentally manipulated 56 splicing factors. Using these data, RNA splicing signatures and gene expression signatures were computed, and signature comparison analysis identified a list of key splicing factors in Rett syndrome and cold-induced thermogenesis. We show that cold-induced RNA-binding proteins rescue the neurite outgrowth defects in Rett syndrome using neuronal morphology analysis, and we also reveal that SRSF1 and PTBP1 are required for energy expenditure in adipocytes using metabolic flux analysis. Our study provides an integrated analysis for identifying key factors in diseases and biological processes and highlights the importance of public data resources for identifying hypotheses for experimental testing.

A systematic flux analysis approach to identify metabolic vulnerabilities in human breast cancer cell lines

Background

Increased flux through both glycolytic and oxidative metabolic pathways is a hallmark of breast cancer cells and is critical for their growth and survival. As such, targeting this metabolic reprograming has received much attention as a potential treatment approach. However, the heterogeneity of breast cancer cell metabolism, even within classifications, suggests a necessity for an individualised approach to treatment in breast cancer patients.

Methods

The metabolic phenotypes of a diverse panel of human breast cancer cell lines representing the major breast cancer classifications were assessed using real-time metabolic flux analysis. Flux linked to ATP production, pathway reserve capacities and specific macromolecule oxidation rates were quantified. Suspected metabolic vulnerabilities were targeted with specific pathway inhibitors, and relative cell viability was assessed using the crystal violet assay. Measures of AMPK and mTORC1 activity were analysed through immunoblotting.

Results

Breast cancer cells displayed heterogeneous energy requirements and utilisation of non-oxidative and oxidative energy-producing pathways. Quantification of basal glycolytic and oxidative reserve capacities identified cell lines that were highly dependent on individual pathways, while assessment of substrate oxidation relative to total oxidative capacity revealed cell lines that were highly dependent on individual macromolecules. Based on these findings, mild mitochondrial inhibition in ESH-172 cells, including with the anti-diabetic drug metformin, and mild glycolytic inhibition in Hs578T cells reduced relative viability, which did not occur in non-transformed MCF10a cells. The effects on viability were associated with AMPK activation and inhibition of mTORC1 signalling. Hs578T were also found to be highly dependent on glutamine oxidation and inhibition of this process also impacted viability.

Conclusions

Together, these data highlight that systematic flux analysis in breast cancer cells can identify targetable metabolic vulnerabilities, despite heterogeneity in metabolic profiles between individual cancer cell lines.

Identification of Fromiamycalin and Halaminol A from Australian Marine Sponge Extracts with Anthelmintic Activity against Haemonchus contortus

There is an urgent need to discover and develop new anthelmintics for the treatment of parasitic nematodes of veterinary importance to circumvent challenges linked to drug resistant parasites. Being one of the most diverse natural ecosystems, the marine environment represents a rich resource of novel chemical entities. This study investigated 2000 extracts from marine invertebrates, collected from Australian waters, for anthelmintic activity. Using a well-established in vitro bioassay, these extracts were screened for nematocidal activity against Haemonchus contortus — a socioeconomically important parasitic nematode of livestock animals. Extracts (designated Mu-1, Ha-1 and Ha-2) from two marine sponges (Monanchora unguiculata and Haliclona sp.) each significantly affected larvae of H. contortus. Individual extracts displayed a dose-dependent inhibition of both the motility of exsheathed third-stage larvae (xL3s) and the development of xL3s to fourth-stage larvae (L4s). Active fractions in each of the three extracts were identified using bioassay-guided fractionation. From the active fractions from Monanchora unguiculata, a known pentacyclic guanidine alkaloid, fromiamycalin (1), was purified. This alkaloid was shown to be a moderately potent inhibitor of L4 development (half-maximum inhibitory concentration (IC₅₀) = 26.6 ± 0.74 µM) and L4 motility (IC₅₀ = 39.4 ± 4.83 µM), although it had a relatively low potency at inhibiting of xL3 motility (IC₅₀ ≥ 100 µM). Investigation of the active fractions from the two Haliclona collections led to identification of a mixture of amino alcohol lipids, and, subsequently, a known natural product halaminol A (5). Anthelmintic profiling showed that 5 had limited potency at inhibiting larval development and motility. These data indicate that fromiamycalin, other related pentacyclic guanidine alkaloids and/or halaminols could have potential as anthelmintics following future medicinal chemistry efforts.

A physiological drop in pH decreases mitochondrial respiration, and HDAC and Akt signaling, in L6 myocytes

Exercise stimulates mitochondrial biogenesis and increases mitochondrial respiratory function and content. However, during high-intensity exercise muscle pH can decrease below pH 6.8 with a concomitant increase in lactate concentration. This drop in muscle pH is associated with reduced exercise-induced mitochondrial biogenesis, while increased lactate may act as a signaling molecule to affect mitochondrial biogenesis. Therefore, in this study we wished to determine the impact of altering pH and lactate concentration in L6 myotubes on genes and proteins known to be involved in mitochondrial biogenesis. We also examined mitochondrial respiration in response to these perturbations. Differentiated L6 myotubes were exposed to normal (pH 7.5)-, low (pH 7.0)-, or high (pH 8.0)-pH media with and without 20 mM sodium l-lactate for 1 and 6 h. Low pH and 20 mM sodium l-lactate resulted in decreased Akt (Ser473) and AMPK (T172) phosphorylation at 1 h compared with controls, while at 6 h the nuclear localization of histone deacetylase 5 (HDAC5) was decreased. When the pH was increased both Akt (Ser473) and AMPK (T172) phosphorylation was increased at 1 h. Overall increased lactate decreased the nuclear content of HDAC5 at 6 h. Exposure to both high- and low-pH media decreased basal mitochondrial respiration, ATP turnover, and maximum mitochondrial respiratory capacity. These data indicate that muscle pH affects several metabolic signaling pathways, including those required for mitochondrial function.

Differential regulation of cellular stress responses by the endoplasmic reticulum-resident Selenoprotein S (Seps1) in proliferating myoblasts versus myotubes

The antioxidant Selenoprotein S (Seps1, Selenos) is an endoplasmic reticulum (ER)-resident protein associated with metabolic and inflammatory disease. While Seps1 is highly expressed in skeletal muscle, its mechanistic role as an antioxidant in skeletal muscle cells is not well characterized. In C2C12 myotubes treated with palmitate for 24 h, endogenous Seps1 protein expression was upregulated twofold. Two different siRNA constructs were used to investigate whether decreased levels of Seps1 exacerbated lipid-induced oxidative and ER stress in C2C12 myotubes and myoblasts, which differ with regards to cell cycle state and metabolic phenotype. In myoblasts, Seps1 protein knockdown of ~50% or ~75% exacerbated cellular stress responses in the presence of palmitate; as indicated by decreased cell viability and proliferation, higher H2 O2 levels, a lower reduced to oxidized glutathione (GSH:GSSG) ratio, and enhanced gene expression of ER and oxidative stress markers. Even in the absence of palmitate, Seps1 knockdown increased oxidative stress in myoblasts. Whereas, in myotubes in the presence of palmitate, a ~50% knockdown of Seps1 was associated with a trend toward a marginal (3-5%) decrease in viability (P = 0.05), decreased cellular ROS levels, and a reduced mRNA transcript abundance of the cellular stress marker thioredoxin inhibitory binding protein (Txnip). Furthermore, no enhancement of gene markers of ER stress was observed in palmitate-treated myotubes in response to Seps1 knockdown. In conclusion, reduced Seps1 levels exacerbate nutrient-induced cellular stress responses to a greater extent in glycolytic, proliferating myoblasts than in oxidative, differentiated myotubes, thus demonstrating the importance of cell phenotype to Seps1 function.

Metabolic reprogramming in type 2 diabetes and the development of breast cancer

A wealth of epidemiological data has found that patients with type 2 diabetes have a greater risk of developing breast cancer. The molecular mechanisms underpinning this relationship are yet to be elucidated; however, this review examines the available evidence suggesting that the metabolic abnormalities observed in type 2 diabetes can predispose to the development of breast cancer. Alterations in substrate availability and the hormonal milieu, particularly hyperinsulinemia, not only create a favorable metabolic environment for tumorigenesis, but also induce metabolic reprogramming events that are required for the transformation of breast cancer cells. In addition, the dysfunction and hypoxia of adipose tissue surrounding the breast cancer niche is another putative link that will be discussed. Finally, the mechanisms by which breast cancer cells evade checkpoints associated with nutrient overload will be examined. Experimentally validating these potential links will be important for prediction and treatment of breast cancer in patients with type 2 diabetes.

Scriptaid enhances skeletal muscle insulin action and cardiac function in obese mice

AIM

To determine the effect of Scriptaid, a compound that can replicate aspects of the exercise adaptive response through disruption of the class IIa histone deacetylase (HDAC) corepressor complex, on muscle insulin action in obesity.

MATERIALS AND METHODS

Diet-induced obese mice were administered Scriptaid (1 mg/kg) via daily intraperitoneal injection for 4 weeks. Whole-body and skeletal muscle metabolic phenotyping of mice was performed, in addition to echocardiography, to assess cardiac morphology and function.

RESULTS

Scriptaid treatment had no effect on body weight or composition, but did increase energy expenditure, supported by increased lipid oxidation, while food intake was also increased. Scriptaid enhanced the expression of oxidative genes and proteins, increased fatty acid oxidation and reduced triglycerides and diacylglycerides in skeletal muscle. Furthermore, ex vivo insulin-stimulated glucose uptake by skeletal muscle was enhanced. Surprisingly, heart weight was reduced in Scriptaid-treated mice and was associated with enhanced expression of genes involved in oxidative metabolism in the heart. Scriptaid also improved indices of both diastolic and systolic cardiac function.

CONCLUSION

These data show that pharmacological targeting of the class IIa HDAC corepressor complex with Scriptaid could be used to enhance muscle insulin action and cardiac function in obesity.

Targeting the undruggable: immunotherapy meets personalized oncology in the genomic era

Owing to recent advances in genomic technologies, personalized oncology is poised to fundamentally alter cancer therapy. In this paradigm, the mutational and transcriptional profiles of tumors are assessed, and personalized treatments are designed based on the specific molecular abnormalities relevant to each patient's cancer. To date, such approaches have yielded impressive clinical responses in some patients. However, a major limitation of this strategy has also been revealed: the vast majority of tumor mutations are not targetable by current pharmacological approaches. Immunotherapy offers a promising alternative to exploit tumor mutations as targets for clinical intervention. Mutated proteins can give rise to novel antigens (called neoantigens) that are recognized with high specificity by patient T cells. Indeed, neoantigen-specific T cells have been shown to underlie clinical responses to many standard treatments and immunotherapeutic interventions. Moreover, studies in mouse models targeting neoantigens, and early results from clinical trials, have established proof of concept for personalized immunotherapies targeting next-generation sequencing identified neoantigens. Here, we review basic immunological principles related to T-cell recognition of neoantigens, and we examine recent studies that use genomic data to design personalized immunotherapies. We discuss the opportunities and challenges that lie ahead on the road to improving patient outcomes by incorporating immunotherapy into the paradigm of personalized oncology.

ATGL-mediated triglyceride turnover and the regulation of mitochondrial capacity in skeletal muscle

Emerging evidence indicates that skeletal muscle lipid droplets are an important control point for intracellular lipid homeostasis and that regulating fatty acid fluxes from lipid droplets might influence mitochondrial capacity. We used pharmacological blockers of the major triglyceride lipases, adipose triglyceride lipase (ATGL) and hormone-sensitive lipase, to show that a large proportion of the fatty acids that are transported into myotubes are trafficked through the intramyocellular triglyceride pool. We next tested whether increasing lipolysis from intramyocellular lipid droplets could activate transcriptional responses to enhance mitochondrial and fatty acid oxidative capacity. ATGL was overexpressed by adenoviral and adenoassociated viral infection in C2C12 myotubes and the tibialis anterior muscle of C57Bl/6 mice, respectively. ATGL overexpression in C2C12 myotubes increased lipolysis, which was associated with increased peroxisome proliferator-activated receptor (PPAR)-∂ activity, transcriptional upregulation of some PPAR∂ target genes, and enhanced mitochondrial capacity. The transcriptional responses were specific to ATGL actions and not a generalized increase in fatty acid flux in the myotubes. Marked ATGL overexpression (20-fold) induced modest molecular changes in the skeletal muscle of mice, but these effects were not sufficient to alter fatty acid oxidation. Together, these data demonstrate the importance of lipid droplets for myocellular fatty acid trafficking and the capacity to modulate mitochondrial capacity by enhancing lipid droplet lipolysis in vitro; however, this adaptive program is of minor importance when superimposing the normal metabolic stresses encountered in free-moving animals.

Mitochondrial dysfunction has divergent, cell type-dependent effects on insulin action

The contribution of mitochondrial dysfunction to insulin resistance is a contentious issue in metabolic research. Recent evidence implicates mitochondrial dysfunction as contributing to multiple forms of insulin resistance. However, some models of mitochondrial dysfunction fail to induce insulin resistance, suggesting greater complexity describes mitochondrial regulation of insulin action. We report that mitochondrial dysfunction is not necessary for cellular models of insulin resistance. However, impairment of mitochondrial function is sufficient for insulin resistance in a cell type-dependent manner, with impaired mitochondrial function inducing insulin resistance in adipocytes, but having no effect, or insulin sensitising effects in hepatocytes. The mechanism of mitochondrial impairment was important in determining the impact on insulin action, but was independent of mitochondrial ROS production. These data can account for opposing findings on this issue and highlight the complexity of mitochondrial regulation of cell type-specific insulin action, which is not described by current reductionist paradigms.

Caveolin-1 orchestrates the balance between glucose and lipid-dependent energy metabolism: implications for liver regeneration

Caveolin-1 (CAV1) is a structural protein of caveolae involved in lipid homeostasis and endocytosis. Using newly generated pure Balb/C CAV1 null ((Balb/C)CAV1-/-) mice, CAV1-/- mice from Jackson Laboratories ((JAX)CAV1-/-), and CAV1-/- mice developed in the Kurzchalia Laboratory ((K)CAV1-/-), we show that under physiological conditions CAV1 expression in mouse tissues is necessary to guarantee an efficient progression of liver regeneration and mouse survival after partial hepatectomy. Absence of CAV1 in mouse tissues is compensated by the development of a carbohydrate-dependent anabolic adaptation. These results were supported by extracellular flux analysis of cellular glycolytic metabolism in CAV1-knockdown AML12 hepatocytes, suggesting cell autonomous effects of CAV1 loss in hepatic glycolysis. Unlike in (K)CAV1-/- livers, in (JAX)CAV1-/- livers CAV1 deficiency is compensated by activation of anabolic metabolism (pentose phosphate pathway and lipogenesis) allowing liver regeneration. Administration of 2-deoxy-glucose in (JAX)CAV1-/- mice indicated that liver regeneration in (JAX)CAV1-/- mice is strictly dependent on hepatic carbohydrate metabolism. Moreover, with the exception of regenerating (JAX)CAV1-/- livers, expression of CAV1 in mice is required for efficient hepatic lipid storage during fasting, liver regeneration, and diet-induced steatosis in the three CAV1-/- mouse strains. Furthermore, under these conditions CAV1 accumulates in the lipid droplet fraction in wildtype mouse hepatocytes.

CONCLUSION

Our data demonstrate that lack of CAV1 alters hepatocyte energy metabolism homeostasis under physiological and pathological conditions.

Determination of intracellular glutathione and glutathione disulfide using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection

Measurement of glutathione (GSH) and glutathione disulfide (GSSG) is a crucial tool to assess cellular redox state. Herein we report a direct approach to determine intracellular GSH based on a rapid chromatographic separation coupled with acidic potassium permanganate chemiluminescence detection, which was extended to GSSG by incorporating thiol blocking and disulfide bond reduction. Importantly, this simple procedure avoids derivatisation of GSH (thus minimising auto-oxidation) and overcomes problems encountered when deriving the concentration of GSSG from 'total GSH'. The linear range and limit of detection for both analytes were 7.5 × 10(-7) to 1 × 10(-5) M, and 5 × 10(-7) M, respectively. GSH and GSSG were determined in cultured muscle cells treated for 24 h with glucose oxidase (0, 15, 30, 100, 250 and 500 mU mL(-1)), which exposed them to a continuous source of reactive oxygen species (ROS). Both analyte concentrations were greater in myotubes treated with 100 or 250 mU mL(-1) glucose oxidase (compared to untreated controls), but were significantly lower in myotubes treated with 500 mU mL(-1) (p < 0.05), which was rationalised by considering measurements of H(2)O(2) and cell viability. However, the GSH/GSSG ratio in myotubes treated with 100, 250 and 500 mU mL(-1) glucose oxidase exhibited a dose-dependent decrease that reflected the increase in intracellular ROS.

Enhanced proliferation of human skeletal muscle precursor cells derived from elderly donors cultured in estimated physiological (5%) oxygen

Human skeletal muscle precursor cells (myoblasts) have significant therapeutic potential and are a valuable research tool to study muscle cell biology. Oxygen is a critical factor in the successful culture of myoblasts with low (1-6%) oxygen culture conditions enhancing the proliferation, differentiation, and/or viability of mouse, rat, and bovine myoblasts. The specific effects of low oxygen depend on the myoblast source and oxygen concentration; however, variable oxygen conditions have not been tested in the culture of human myoblasts. In this study, muscle precursor cells were isolated from vastus lateralis muscle biopsies and myoblast cultures were established in 5% oxygen, before being divided into physiological (5%) or standard (20%) oxygen conditions for experimental analysis. Five percent oxygen increased proliferating myoblast numbers, and since low oxygen had no significant effect on myoblast viability, this increase in cell number was attributed to enhanced proliferation. The proportion of cells in the S (DNA synthesis) phase of the cell cycle was increased by 50%, and p21(Cip1) gene and protein expression was decreased in 5 versus 20% oxygen. Unlike in rodent and bovine myoblasts, the increase in myoD, myogenin, creatine kinase, and myosin heavy chain IIa gene expression during differentiation was similar in 5 and 20% oxygen; as was myotube hypertrophy. These data indicate for the first time that low oxygen culture conditions stimulate proliferation, whilst maintaining (but not enhancing) the viability and the differentiation potential of human primary myoblasts and should be considered as optimum conditions for ex-vivo expansion of these cells.

A new approach for assessing early osteoarthritis in the rat

Several animal models have been developed to investigate osteoarthritis and potential disease-modifying therapeutics. However, early disease data from these models are limited by the resolution of current imaging modalities. In this in-vitro study, an optical coherence tomography (OCT) system with an axial resolution of 15 micro m was used to track sequential changes in osteoarthritic rat knees. Osteoarthritis was induced via transection of the medial collateral ligament and an artificial full thickness meniscal tear. Imaging occurred at one, two, and three weeks after surgery. OCT successfully detected early signs of osteoarthritic change, including alteration of the cartilage surface and disruption of the bone-cartilage interface. This study demonstrates that OCT, along with the induction of mechanical injury, provides an excellent model for monitoring the sequential changes of osteoarthritis.

Dynamic lateral patellar tilt in the anterior cruciate ligament-deficient knee. A magnetic resonance imaging analysis

An open-configuration magnetic resonance imaging scanner was used to document patellar tracking abnormalities in 11 anterior cruciate ligament-injured knees. The contralateral normal knees were used as controls. Images were obtained with the quadriceps muscles at rest (knee flexion at 40 degrees, 25 degrees, and 10 degrees) and with the quadriceps muscles contracted (knee flexion at 40 degrees and 25 degrees). When the quadriceps muscles were at rest there were no differences in patellar alignment between the anterior cruciate ligament-injured knees and the contralateral normal knees. When the quadriceps muscles were maximally contracted at 40 degrees of flexion, the patellae of the anterior cruciate ligament-injured knees tilted laterally 3.6 degrees relative to the resting state. When the quadriceps muscles were contracted at 25 degrees of flexion, the patellae of the anterior cruciate ligament-injured knees tilted laterally approximately 4 degrees relative to the resting state. Quadriceps-active lateral patellar tilt at 25 degrees of flexion was greater in the anterior cruciate ligament-injured knees than in the contralateral normal knees, and it correlated with instrumented measurements of anterior tibial translation. Dynamic lateral patellar tilt during open kinetic chain exercises and during other activities that produce anterior tibial translation may contribute to extensor mechanism dysfunction in the anterior cruciate ligament-injured knee.

Brain blood flow changes in depressed patients treated with interpersonal psychotherapy or venlafaxine hydrochloride: preliminary findings

BACKGROUND

Functional brain imaging studies in major depression have suggested abnormalities of areas, including the frontal cortex, cingulate gyrus, basal ganglia, and temporal cortex. We hypothesized that venlafaxine hydrochloride and interpersonal psychotherapy (IPT) might each alter brain blood flow in some or all of these areas on sequential single photon emission computed tomography (SPECT) scans.

METHODS

Twenty-eight men and women aged 30 to 53 years with a DSM-IV major depressive episode, a 17-item Hamilton Rating Scale for Depression (HAM-D) rating of 18 or higher, and antidepressant-naive for at least 6 months were studied. After baseline (99m)technetium-hexa-methyl-propylene-amine-oxime scan, 1-T magnetic resonance imaging, and psychometric ratings, patients were assigned to different treatments. Thirteen patients had 1-hour weekly sessions of IPT from the same supervised therapist (E.M.). Fifteen patients took 37.5 mg twice-daily of venlafaxine hydrochloride. Single-photon emission computed tomography scans and ratings were repeated at 6 weeks.

RESULTS

Both treatment groups improved substantially, more so with venlafaxine (mean [SD] HAM-D scores at pretreatment: IPT, 22.7 [2.7], and venlafaxine, 22.4 [3.1]; and posttreatment: IPT, 16.2 [7.1], and venlafaxine, 10.9 [8.6]). No patients had structural brain abnormalities. On analysis with statistical parametric mapping 96, the venlafaxine group showed right posterior temporal and right basal ganglia activation (P =.01), while the IPT group had limbic right posterior cingulate and right basal ganglia activation (P =.01).

CONCLUSIONS

This preliminary investigation has shown limbic blood flow increase with IPT yet not venlafaxine, while both treatments demonstrated increased basal ganglia blood flow. This was, however, a short trial with a small sample, no control group, and different symptom reduction in the 2 groups.

Distribution of smooth muscle actin-containing cells in the human meniscus

This is the first report of a contractile actin isoform, a-smooth muscle actin (SMA), in the cells of the human meniscus that lacked meniscal tears based on gross anatomical appearance. Approximately 25% of the cells in the tissue contained SMA by immunohistochemistry. Most of the SMA-positive cells were chondrocytic in morphology.

Arthroscopic resection of the distal aspect of the clavicle with concomitant subacromial decompression

BACKGROUND

Arthroscopic subacromial decompression and arthroscopic resection of the acromioclavicular joint as separate procedures have been well documented. However, there is little information on the success rate of resection with concomitant decompression. In this study, we retrospectively evaluated the results of a consecutive group of patients who underwent arthroscopic resection of the acromioclavicular joint with concomitant subacromial decompression.

METHODS

We evaluated the surgical results in thirty-one consecutive patients (thirty-two shoulders) with acromioclavicular pathology with concomitant subacromial impingement. The mean age of the patients at the time of surgery was thirty-six years (range, eighteen to sixty-seven years). Twenty-five patients, including four professional athletes, were actively involved in sports activities. The mean duration of follow-up was four years and ten months (range, three to eight years). The follow-up examination included clinical evaluation, chart review, radiographic analysis, and isokinetic testing of both upper extremities.

RESULTS

Of the twenty-five patients who participated in sports, twenty-two (including the four professional athletes) returned to their previous level of sports activity. Twenty-six patients had no pain, three reported mild pain on strenuous repetitive overhead activity, two (both weight-lifters) had occasional pain in the acromioclavicular joint and the lateral aspect of the shoulder with bench-pressing, and two (both baseball players) had mild pain in the posterior aspect of the shoulder with throwing. All of the patients were satisfied with the results. In the absence of a complete rotator cuff tear, isokinetic strength-testing of both upper extremities failed to demonstrate any weakness of the involved shoulder. The mean functional score for individual activities was 2.7 points (range, 2.1 to 3.0 points) preoperatively and 3.9 points (range, 3.6 to 4.0 points) postoperatively (p = 0.0001). No patient had superior migration of the clavicle. The amount of distal clavicular resection averaged 9 mm (range, 7 to 15 mm). One patient had heterotopic ossification at the resection site, with mild pain on direct palpation of the acromioclavicular joint and on strenuous overhead activity. Five patients had calcification at the anterior deltoid insertion into the acromion that was asymptomatic, with no impingement on overhead activity and no pain on direct palpation.

CONCLUSIONS

We found excellent results with arthroscopic resection of the acromioclavicular joint and concomitant subacromial decompression. When this procedure is performed on properly selected patients, the results are similar to those of an open approach.

Histological changes in the human anterior cruciate ligament after rupture

BACKGROUND

Four phases in the response to injury of the ruptured human anterior cruciate ligament are observed histologically; these include an inflammatory phase, an epiligamentous repair phase, a proliferative phase, and a remodeling phase. One objective of this study was to describe the histological changes that occur in the ruptured human anterior cruciate ligament during these phases. Myofibroblast-like cells that contain alpha-smooth muscle actin are present in the midsubstance of the intact human anterior cruciate ligament. A second objective of this study was to determine whether an increased number of myofibroblast-like cells is found in the midsubstance of the ruptured human anterior cruciate ligament because it was thought that those cells might be responsible in part for the retraction of the ruptured anterior cruciate ligament. In the early phase of this study, it was found that the number of myofibroblast-like cells in the midsubstance of the ruptured anterior cruciate ligament was actually decreased, and this hypothesis was abandoned. During the epiligamentous repair phase, synovial tissue was formed that covered the ends of the ruptured anterior cruciate ligament. Most of the synovial lining cells were myofibroblast-like cells that contained alpha-smooth muscle actin. The primary objective of this study was to determine the location and the characteristics of the alpha-smooth muscle actin-containing myofibroblast-like cells that appear in the human anterior cruciate ligament following rupture.

METHODS

Twenty-three ruptured and ten intact human anterior cruciate ligaments were evaluated for cellularity, nuclear morphology, blood vessel density, and percentage of cells containing a contractile actin isoform, alpha-smooth muscle actin. The histological features of the synovial and epiligamentous tissues were also described.

RESULTS

At no time after rupture was there evidence of tissue-bridging between the femoral and tibial remnants of the anterior cruciate ligament. The ruptured ligaments demonstrated a time-dependent histological response, which consisted of inflammatory cell infiltration up to three weeks, gradual epiligamentous repair and resynovialization between three and eight weeks, and neovascularization and an increase in cell number density between eight and twenty weeks. Compared with the intact ligaments, there was a decrease in the percentage of myofibroblast-like cells containing alpha-smooth muscle actin within the remnant of the ligament. However, many of the epiligamentous and synovial cells encapsulating the remnants contained alpha-smooth muscle actin.

CONCLUSIONS

After rupture, the human anterior cruciate ligament undergoes four histological phases, consisting of inflammation, epiligamentous regeneration, proliferation, and remodeling. The response to injury is similar to that reported in other dense connective tissues, with three exceptions: formation of an alpha-smooth muscle actin-expressing synovial cell layer on the surface of the ruptured ends, the lack of any tissue bridging the rupture site, and the presence of an epiligamentous reparative phase that lasts eight to twelve weeks. Other characteristics reported in healing dense connective tissue, such as fibroblast proliferation, expression of alpha-smooth muscle actin, and revascularization, also occur in the ruptured human anterior cruciate ligament.

CLINICAL RELEVANCE

Unlike extra-articular ligaments that heal after injury, the human intra-articular anterior cruciate ligament forms a layer of synovial tissue over the ruptured surface, which may impede repair of the ligament. Moreover, a large number of cells in this synovial layer and in the epiligamentous tissue express the gene for a contractile actin isoform, alpha-smooth muscle actin, thus differentiating into myofibroblasts. These events may play a role in the retraction and lack of healing of the ruptured anterior cruciate ligament.

Outgrowth of chondrocytes from human articular cartilage explants and expression of alpha-smooth muscle actin

The objectives of this study were to investigate the effect of various enzymatic treatments on the outgrowth of chondrocytes from explants of adult human articular cartilage and the expression of a specific contractile protein isoform, alpha-smooth muscle actin, known to facilitate wound closure in other connective tissues. Explants of articular cartilage were prepared from specimens obtained from patients undergoing total joint arthroplasty. The time to cell outgrowth in vitro was determined and the expression of alpha-smooth muscle actin shown by immunohistochemistry. Treatment of the explants with collagenase for 15 minutes reduced the time to outgrowth from more than 30 days to 3 days. Hyaluronidase, chondroitinase ABC, and trypsin applied for the 15-minute period had no effect on the time to cell outgrowth when compared with untreated controls. Pretreatment with hyaluronidase prior to collagenase reduced the time to outgrowth. A notable finding of this study was that the majority of chondrocytes in the adult human articular cartilage specimens and virtually all of the outgrowing cells contained alpha-smooth muscle actin. We conclude that human articular chondrocytes have the capability to migrate through enzymatically degraded matrix and express a contractile actin isoform. Collagenase treatment reduces the time required for cell outgrowth.

Effects of harvest and selected cartilage repair procedures on the physical and biochemical properties of articular cartilage in the canine knee

This study utilizes a canine model to quantify changes in articular cartilage 15-18 weeks after a knee joint is subjected to surgical treatment of isolated chondral defects. Clinical and experimental treatment of articular cartilage defects may include implantation of matrix materials or cells, or both. Three cartilage repair methods were evaluated: microfracture, microfracture and implantation of a type-II collagen matrix, and implantation of an autologous chondrocyte-seeded collagen matrix. The properties of articular cartilage in other knee joints subjected to harvest of articular cartilage from the trochlear ridge (to obtain cells for the cell-seeded procedure) were also evaluated. Physical properties (thickness, equilibrium compressive modulus, dynamic compressive stiffness, and streaming potential) and biochemical composition (hydration, glycosaminoglycan content, and DNA content) of the cartilage from sites distant to the surgical treatment were compared with values measured for site-matched controls in untreated knee joints. No significant differences were seen in joints subjected to any of the three cartilage repair procedures. However, a number of changes were induced by the harvest operation. The largest changes (displaying up to 3-fold increases) were seen in dynamic stiffness and streaming potential of patellar groove cartilage from joints subjected to the harvest procedure. Whether the changes reported will lead to osteoarthritic degeneration is unknown, but this study provides evidence that the harvest procedure associated with autologous cell transplantation for treatment of chondral defects may result in changes in the articular cartilage in the joint.

Healing of canine articular cartilage defects treated with microfracture, a type-II collagen matrix, or cultured autologous chondrocytes

The effects of three different treatments on the healing of articular cartilage defects were compared with use of a previously developed canine model. In the articular surface of the trochlear grooves of 12 adult mongrel dogs, two 4-mm-diameter defects were made to the depth of the tidemark. Four dogs were assigned to each treatment group: (a) microfracture treatment, (b) microfracture with a type-II collagen matrix placed in the defect, and (c) type-II matrix seeded with cultured autologous chondrocytes. After 15 weeks, the defects were studied histologically. Data quantified on histological cross sections included areal or linear percentages of specific tissue types filling the defect, integration of reparative tissue with the calcified and the adjacent cartilage, and integrity of the subchondral plate. Total defect filling (i.e., the percentage of the cross-sectional area of the original defect filled with any type of reparative tissue) averaged 56-86%, with the greatest amount found in the dogs in the microfracture group implanted with a type-II collagen matrix. The profiles of tissue types for the dogs in each treatment group were similar: the tissue filling the defect was predominantly fibrocartilage, with the balance being fibrous tissue. There were no significant differences in the percentages of the various tissue types among dogs in the three groups.

Migration of cells from human anterior cruciate ligament explants into collagen-glycosaminoglycan scaffolds

Regeneration of the human anterior cruciate ligament after complete rupture offers several theoretical advantages over reconstruction, including maintenance of the complex insertion sites and fan-shape of the ligament and preservation of remaining proprioceptive fibers within the ligament substance. Well vascularized connective tissues, such as dermis, heal as a result of migration of fibroblasts into a provisional scaffold, the fibrin clot. Wound closure is subsequently facilitated by a contractile cell phenotype. This study was designed to determine if fibroblasts intrinsic to the human anterior cruciate ligament were capable of migrating from their native extracellular matrix onto an adjacent provisional scaffold in vitro. Another objective was to determine whether any of the cells that successfully migrated into the scaffold expressed the contractile actin isoform, alpha-smooth muscle actin, associated with wound contraction in other tissues. The results demonstrated that the cells intrinsic to the human anterior cruciate ligament were able to migrate into a collagen-glycosaminoglycan scaffold, bridging a gap between transected fascicles in vitro. As a result of this cell migration and proliferation, areas in the scaffold contained cell number densities similar to those seen in the human anterior cruciate ligament in vivo. No extracellular matrix or tissue formation was seen in the gap between directly apposed transected ends of the anterior cruciate ligament explants cultured without an interposed collagen-glycosaminoglycan scaffold. The fascicle-collagen-glycosaminoglycan-fascicle constructs and the fascicle-fascicle explants displayed minimal adherence after 6 weeks in culture. Any disruption in the contact area between explant and scaffold, even as small a gap as 50 microm, prevented cell migration from the explant to the collagen-glycosaminoglycan scaffold at the area of loss of contact. All cells that migrated into the scaffold at early time periods expressed the alpha-smooth muscle actin isoform. These results demonstrate that cells that migrate into and proliferate within the collagen-glycosaminoglycan matrix have contractile potential as reflected in their expression of the alpha-smooth muscle actin isoform. The role of these contractile cells in the healing process warrants further investigation. Moreover, this study demonstrates the potential of cells intrinsic to the human anterior cruciate ligament to migrate into collagen-glycosaminoglycan scaffolds that may ultimately be investigated as implants to facilitate ligament healing and regeneration.

Switching from depot antipsychotics to risperidone: results of a study of chronic schizophrenia. The Schizophrenia Treatment & Assessment Group

Designed to provide information about patients with schizophrenia who switch from depot neuroleptics to the oral, atypical antipsychotic risperidone, this multicenter observational study enrolled patients who wished to stop the depot, had an unsatisfactory response, or experienced unacceptable side effects. Individuals remained on depot medication for 4 weeks and then received risperidone monotherapy for 3 months. Of the 143 patients who entered the study, 130 received risperidone, 109 completed the initial 16-week study, and 88 entered an optional 12-week follow-up. Symptoms and side effects did not change significantly during the depot phase (mean Positive and Negative Syndrome Scale [PANSS] score 72.2 at baseline, 71.6 at visit 2), but PANSS scores, global assessment of functioning, parkinsonism, and dyskinesia improved significantly during the risperidone phase (mean PANSS score decreased from 71.6 to 55.5 after 3 months). The number of contacts with healthcare professionals fell significantly during the risperidone phase; in addition, symptomatic improvements were maintained during follow-up, and movement disorders continued to decrease significantly. The investigators considered that 81% of patients had switched successfully. Patient acceptance of risperidone was significantly higher than for depot medication (83% vs 23%; P < .001), and 65% considered risperidone better than their previous treatment. Indications for depot medication should be reviewed, and patients may benefit from a switch to risperidone.

Current concepts of total knee arthroplasty

Total knee arthroplasty has become a reliable surgical procedure to treat painful degenerative arthritis. Pain relief and functional improvement is excellent and can allow patients to maintain an active lifestyle. Criteria for the type of prostheses selected should include diagnosis, age, functional level, severity of the disease, and patient expectations. Improved instrumentation, attention to surgical detail, including soft tissue balancing of the knee, and the use of polyethylene inserts greater than 8 mm have led to excellent long-term results and low failure rates. Recent improvements in revision total knee systems should significantly improve the long-term results of revision knee arthroplasty. The addition of modular implants has greatly increased the versatility of most systems and allows the surgeon to custom tailor the implant, contingent upon the amount of bony and ligamentous deficiency of the knee. The future goals of total knee arthroplasty include the development of knee systems that mimic normal joint kinematics with improved fixation and decreased polyethylene wear rates.

Press-fit condylar total knee arthroplasty. 5- to 9-year follow-up evaluation

Between November 1984 and December 1987, 378 consecutive Press-Fit Condylar (PFC, Johnson & Johnson Professional, Raynham, MA) total knee arthroplasties were performed in 290 patients. The average age at surgery was 67 years (range, 22-91 years). The average follow-up period was 6.5 years (range, 5-9 years). Scoring was carried out according to the Knee Society scoring system. The average preoperative knee score was 28, and the average postoperative knee score was 88. The average preoperative functional knee score was 49, and the average postoperative functional knee score was 72. Ninety-five percent of the patients had no pain on level walking and were satisfied with their functional result. The average postoperative knee flexion was 110 degrees. No implant showed any evidence of radiographic loosening. There were 17 complications, all requiring reoperation. Complications included excessive wear of a metal-backed patella in 8 knees. If complications resulting from the earlier use of a metal-backed patella are eliminated, the overall complication rate is 2.9%, which is comparable to or lower than the rates for other total knee systems with similar follow-up periods.

Suprascapular neuropathy. Results of non-operative treatment

We retrospectively reviewed the results of non-operative treatment of suprascapular neuropathy in fifteen patients seen between November 1983 and February 1991. The clinical diagnosis was confirmed with electrodiagnostic studies. The treatment consisted of a program of physical therapy to improve the range of motion of the shoulder and to strengthen the surrounding muscles. The average duration of follow-up was three years and eleven months (range, one year to eight years and ten months). The latest evaluation included electrodiagnostic studies of the affected extremity and dynamic isokinetic testing of both upper extremities. The result was excellent for five patients and good for seven. The three remaining patients had operative treatment because of persistent symptoms; one of these patients had an excellent result, one had a good result, and one had a poor result. The results suggest that, in the absence of a well defined lesion producing mechanical compression of the suprascapular nerve, suprascapular neuropathy should be treated non-operatively.

Primary total knee arthroplasty after patellectomy

The results of twenty-two consecutive primary total knee replacements, performed an average of nine years (range, one to twenty-three years) after a patellectomy in twenty-two patients, were reviewed retrospectively. The average duration of follow-up was seven years (range, three to fifteen years). The average age of the patients at the time of the arthroplasty was sixty-seven years (range, thirty-six to eighty-nine years). The average Hospital for Special Surgery knee score was 46 points (range, 22 to 74 points) preoperatively and 76 points (range, 45 to 97 points) postoperatively. Thirteen patients had an excellent or good result and seven had a fair or poor result; in two patients, the operation was considered a failure. Except for one patient who had myasthenia gravis, all patients could climb stairs in reciprocal manner. Four patients lacked 5 to 20 degrees of active extension compared with passive extension. With respect to the over-all results, there was no significant difference among the four types of prostheses that were used (p = 0.2). The patients who had received an Insall-Burstein posterior stabilized prosthesis had better scores for pain and function than did the patients who had received a total condylar I prosthesis (p = 0.005 and 0.01, respectively). There was a direct correlation between the knee score and the number of years that had elapsed since the patellectomy. The longer the interval between the patellectomy and the total knee replacement, the higher the postoperative knee score (r = 0.78, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Coping with chronic illness

Families suffer in many ways when a member is stricken with chronic illness. Nurses frequently feel a sense of frustration when working with the chronically ill because cure is not possible. The author reviews the goals of care and coping tasks common to the chronically ill. Family coping styles are reviewed with suggestions for effective nurse behaviors with each style.

Proximal tibial osteotomy with compression plate fixation for tibia vara

A surgical technique for the accurate intraoperative correction of tibia vara deformities with maintainence of postoperative alignment is presented. This was a retrospective study of 13 knees of nine patients with tibia vara deformities treated by proximal tibial and fibular osteotomies using compression-plate fixation. Average age of the patients was 9 + 1 years, with a range of 3 + 1 to 14 + 11 years. The average preoperative deformity was 20 degrees of varus with a range of 15-36 degrees. Average follow-up was 3 + 3 years, with a range of 2 to 4 + 1 years. All patients had intraoperative correction to an average valgus of 5 degrees (range 4-8 degrees valgus), with an overall valgus correction of 25 degrees (range 20-40 degrees). There was one reoperation for unilateral recurrence of deformity in a child who progressed from stage III to stage VI postoperatively. Proximal tibial osteotomy with compression-plate fixation provides an accurate and reliable method for the correction of multiplanar deformities in children and adolescents.

Missed scapular fracture after trauma. A case report and a 23-year follow-up report

Scapular fractures are important in that they are often associated with high morbidity and mortality. Frequently they are overlooked because of the severity of other associated injuries. Extraarticular scapular fractures are often treated conservatively, even when displaced. There is no significant long-term evaluation on this type of treatment and on the management of scapular malunion. This case report presents a missed scapular fracture and associated rib fractures with subsequent malunion and a 23-year follow-up assessment. Surgical resection of a distorted inferior medial border of the scapula and dorsal rib prominences relieved the patient's symptoms. The case presentation, diagnostic modalities, treatment, and possible long-term sequelae of this complex fracture are reviewed.

Atraumatic posterior dislocation of the sternoclavicular joint. A case report and literature review

Atraumatic spontaneous posterior dislocation of the sternoclavicular joint (SCJ) is an extremely rare event. Only three recorded cases exist in the literature, and they are poorly documented and without roentgenographic confirmation. Spontaneous posterior dislocation of the SCJ occurred in an active 50-year-old woman without any known underlying pathology. Closed reduction attempted five days later was unsuccessful, and the patient was treated conservatively with short-term modification of activity. The patient is asymptomatic and followed carefully one year postdislocation. A review of the literature discloses a 25% complication rate involving the vital structures of the superior mediastinum after posterior dislocation of the SCJ. Because of this high complication rate, a thoracic or vascular surgeon must be available should closed or open reduction become necessary.

Acute exacerbation of carpal tunnel syndrome after radial artery cannulation

Acute carpal tunnel syndrome that follows radial artery cannulation has been described. To determine the incidence and predisposing factors, we prospectively studied 151 patients who had perioperative radial artery cannulation. Postoperatively 9 of the 151 patients had symptoms of carpal tunnel syndrome with positive Phalen and Tinel signs on the side on which the radial artery catheter had been inserted. Eight of 12 patients with a prior history of carpal tunnel syndrome had acute exacerbation of symptoms postoperatively. By contrast, only 1 of 139 patients with no prior history of the disorder had symptoms. Fourteen patients had multiple arterial artery punctures or perforations of the posterior wall of the radial artery. In three of these, postoperative symptoms of carpal tunnel syndrome developed but did not reach statistical significance. The only patient with postoperative acute carpal tunnel syndrome but no prior history of the syndrome had multiple arterial punctures. The use of perioperative anticoagulation, the use of wrist-extension splints, and the duration of radial artery cannulation did not influence acute exacerbation of carpal tunnel syndrome. Patients with a prior history of carpal tunnel syndrome are at increased risk of recurrent symptoms after radial artery cannulation. We found no statistically significant relationship between traumatic cannulations and the development of symptoms of carpal tunnel syndrome.

Evaluation of hemostatic analytes after use of hypertonic saline solution combined with colloids for resuscitation of dogs with hypovolemia

The effects of hypertonic saline solution (HTSS) combined with colloids on hemostatic analytes were studied in 15 dogs. The analytes evaluated included platelet counts, one-stage prothrombin time, activated partial thromboplastin time, von Willebrand's factor antigen (vWf:Ag), and buccal mucosa bleeding times. The dogs were anesthetized, and jugular phlebotomy was used to induced hypovolemia (mean arterial blood pressure = 50 mm of Hg). Treatment dogs (n = 12) were resuscitated by infusion (6 ml/kg of body weight) of 1 of 3 solutions: HTSS combined with 6% dextran 70, 6% hetastarch, or 10% pentastarch. The control dogs (n = 3) were autotransfused. Hemostatic analytes were evaluated prior to induction of hypovolemia (baseline) and then after resuscitation (after 30 minutes of sustained hypovolemia) at 0.25, 0.5, 1, 6 and 24 hours. All treatment dogs responded rapidly and dramatically to resuscitation with hypertonic solutions. Clinically apparent hemostatic defects (epistaxis, petechiae, hematoma) were not observed in any dog. All coagulation variables evaluated, with the exception of vWf:Ag, remained within reference ranges over the 24-hour period. The vWf:Ag values were not statistically different than values from control dogs, and actual values were only slightly lower than reference ranges. Significant (P < or = 0.04) differences were detected for one-stage prothrombin time, but did not exceed reference ranges. The results of this study suggested that small volume HTSS/colloid solutions do not cause significant alterations in hemostatic analytes and should be considered for initial treatment of hypovolemic or hemorrhagic shock.

A field comparison of the pharyngeotracheal lumen airway and the endotracheal tube

A prospective, sequential study compared ease of use and bag-valve ventilation delivered by an endotracheal tube (ET) with that of the pharyngeotracheal lumen airway (PtL) for 111 victims of cardiac arrest in the pre-hospital setting. The PtL airway was found to be significantly easier to use as measured by the time required to intubate the patient and the number of attempts to place the device. Arterial blood gas determinations were made on arrival at the hospital and repeated 15 minutes later. No statistical significance could be found between the two airway devices for either the first or second blood gas determination. During PtL ventilation, the first arterial blood gas values were PaCO2, 58 +/- 32 mm Hg; PaO2, 163 +/- 180 mm Hg; pH, 7.15 +/- 0.22. During ET ventilation the first arterial blood gas values were PaCO2, 53 +/- 29 mm Hg; PaO2, 156 +/- 178 mm Hg; pH, 7.16 +/- 0.23. No adverse effects were reported. We conclude that the ability of the PtL to deliver effective ventilation is comparable with that of the ET as measured by arterial PCO2. When the ET method of airway control cannot be achieved, the PtL airway offers an effective alternative.

Clinical ratings and plasma HVA during cocaine abstinence

Six patients were evaluated over a 21-day period during inpatient recovery from chronic repeated cocaine use. Serial evaluations of Hamilton depression rating, cocaine craving, plasma homovanillic acid (pHVA), and plasma 3-methoxy-4-hydroxyphenylethyleneglycol (pMHPG) concentrations were determined. There was a distinct increase in cocaine craving between 1 and 2 weeks after the last cocaine use. Levels of pHVA also increased at the time of heightened craving. The data provide preliminary evidence to suggest that changes in cocaine craving during abstinence are positively correlated with changes in dopamine turnover.