Alterations in quadriceps muscle cellular and molecular properties in adults with moderate knee osteoarthritis.

OBJECTIVE: Quadriceps muscle weakness is common in knee osteoarthritis (OA). While pain, disuse, and atrophy are commonly cited causes for muscle weakness in OA, emerging evidence suggests changes in muscle quality also occur. Alterations in muscle quality are not well understood, but likely include both cellular and morphologic adaptions. The purpose of this study was to conduct the first cellular-level analysis of the vastus lateralis in adults with moderate knee OA. METHODS: Vastus lateralis biopsies were obtained from 24 subjects with moderate knee OA and 15 healthy controls. Quadriceps strength, muscle fiber cross sectional area (CSA), fiber type distribution, extracellular matrix (ECM) content, satellite cell abundance, and profibrotic gene expression were assessed. RESULTS: Relative to controls, quadriceps strength was significantly lower in OA subjects (OA 62.23, 50.67-73.8 Nm vs 91.46, 75.91-107.0 Nm, P = 0.003) despite no difference in fiber CSA. OA subjects had significantly fewer Type I fibers (OA 41.51, 35.56-47.47% vs 53.07, 44.86-61.29%, P = 0.022) and more hybrid IIa/x fibers (OA 24.61, 20.61-28.61% vs 16.4, 11.60-21.20%, P = 0.009). Significantly greater ECM content, lower satellite cell density, and higher profibrotic gene expression was observed with OA, and muscle collagen content was inversely correlated to strength and satellite cell (SC) density. CONCLUSION: Lower quadriceps function with moderate OA may not result from fiber size impairments, but is associated with ECM expansion. Impaired satellite cell density, high profibrotic gene expression, and a slow-to-fast fiber type transition may contribute to reduced muscle quality in OA. These findings can help guide therapeutic interventions to enhance muscle function with OA.

Carboxylated and uncarboxylated forms of osteocalcin directly modulate the glucose transport system and inflammation in adipocytes.

Osteocalcin is secreted by osteoblasts and improves insulin sensitivity in vivo, although mechanisms remain unclear. We tested the hypothesis that osteocalcin directly modulates cell biology in insulin-targeted peripheral tissues. In L-6 myocytes, osteocalcin stimulated glucose transport both in the absence (basal) and presence of insulin. Similarly, in primary cultured adipocytes, both carboxylated and uncarboxylated osteocalcin increased basal and insulin-stimulated glucose transport as well as insulin sensitivity. Osteocalcin also increased basal and insulin-stimulated glucose oxidation, though there was no effect on fatty acid synthesis or lipolysis. In primary-cultured adipocytes, both forms of osteocalcin suppressed secretion of tumor necrosis factor alpha into the media; however, only carboxylated osteocalcin suppressed interleukin 6 release, and neither form of osteocalcin modulated monocyte chemoattractant protein-1 secretion. Both carboxylated and uncarboxylated osteocalcin increased secretion of adiponectin and the anti-inflammatory cytokine interleukin 10. In conclusion, both carboxylated and uncarboxylated osteocalcin directly increase glucose transport in adipocytes and muscle cells, while suppressing proinflammatory cytokine secretion and stimulating interleukin 10 and adiponectin release. Thus, these results provide a mechanism for the insulin-sensitizing effects of osteocalcin and help elucidate the role that bone plays in regulating systemic metabolism.

Prostaglandin A2 enhances cellular insulin sensitivity via a mechanism that involves the orphan nuclear receptor NR4A3.

We have previously reported that members of the NR4A family of orphan nuclear receptors can augment insulin's ability to stimulate glucose transport in adipocytes. In the current study, we endeavored to test for an insulin-sensitizing effect in muscle cells and to identify a potential transactivator. Lentiviral constructs were used to engineer both hyperexpression and shRNA silencing of NR4A3 in C2C12 myocytes. The NR4A3 hyper-expression construct led to a significant increase in glucose transport rates in the presence of maximal insulin while the NR4A3 knock-down exhibited a significant reduction in insulin-stimulated glucose transport rates. Consistently, insulin-mediated AKT phosphorylation was increased by NR4A3 hyperexpression and decreased following shRNA NR4A3 suppression. Then, we examined effects of prostaglandin A2 (PGA2) on insulin action and NR4A3 transactivation. PGA2 augmented insulin-stimulated glucose uptake in C2C12 myocytes and AKT phosphorylation after 12-h treatment, without significant effects on basal transport or basal AKT phosphorylation. More importantly, we demonstrated that PGA2 led to a greater improvement in insulin-stimulated glucose rates in NR4A3 overexpressing C2C12 myocytes, when compared with Lac-Z controls stimulated with insulin and PGA2. Moreover, the sensitizing effect of PGA2 was significantly diminished in NR4A3 knockdown myocytes compared to scramble controls. These results show for the first time that: (i) PGA2 augments insulin action in myocytes as manifested by enhanced stimulation of glucose transport and AKT phosphorylation; and (ii) the insulin sensitizing effect is dependent upon the orphan nuclear receptor NR4A3.

No effect of dietary fat on short-term weight gain in mice treated with atypical antipsychotic drugs.

RATIONALE: Atypical antipsychotic drugs (AAD) induce significant weight gain in female C57BL/6J mice. The effect of dietary fat on weight gain and serum lipids in this model is unknown. OBJECTIVES: Test the hypothesis that the obesigenic effects of these drugs are greater in the presence of a high-fat diet. METHODS: Female C57BL/6J mice were treated with atypical antipsychotics for 3 weeks and fed either a low-fat or high-fat diet (4.6 vs 15.6% fat by wt). Food intake (FI), body weight (BW), body composition, and serum lipids were measured during treatment with optimized doses of olanzapine, quetiapine, and risperidone. Energy intake (EI) and feed efficiency (FE) were calculated. Group differences in change were analyzed via repeated measures analysis of variance (ANOVA). Serum lipid concentrations, EI and FE were compared using two-way ANOVA. RESULTS: AAD-treated mice gained significantly more weight than controls after 3 weeks (P<0.001). Treatment and diet had significant effects on FI and EI over time (P<0.001). AAD-treated mice had significantly higher FE than controls (P<0.05); however, there was no significant drug by diet interaction (P=0.65). Risperidone low-fat mice gained significantly more absolute fat mass than placebo low-fat mice (P<0.05). All treatment groups, except quetiapine low-fat and olanzapine high-fat, gained significantly more absolute lean mass than placebo controls (P<0.05). Cholesterol levels were significantly lower in quetiapine and risperidone than placebo (P<0.05). Risperidone low-fat mice had significantly higher triglyceride levels than placebo and risperidone high-fat mice (P<0.05). CONCLUSIONS: A high-fat diet does not increase AAD-induced BW gain in female mice during a 3-week treatment period.

Adverse reactions to aspartame: double-blind challenge in patients from a vulnerable population.

This study was designed to ascertain whether individuals with mood disorders are particularly vulnerable to adverse effects of aspartame. Although the protocol required the recruitment of 40 patients with unipolar depression and a similar number of individuals without a psychiatric history, the project was halted by the Institutional Review Board after a total of 13 individuals had completed the study because of the severity of reactions within the group of patients with a history of depression. In a crossover design, subjects received aspartame 30 mg/kg/day or placebo for 7 days. Despite the small n, there was a significant difference between aspartame and placebo in number and severity of symptoms for patients with a history of depression, whereas for individuals without such a history there was not. We conclude that individuals with mood disorders are particularly sensitive to this artificial sweetener and its use in this population should be discouraged.

Mood disorders. Is your primary care patient depressed?

Treatment of patients with mood disorder can be one of the most rewarding experiences in medicine. Optimal treatment is contingent on accurate diagnosis according to current criteria and terminology. Major depression needs further categorization in reference to atypical or psychotic features, seasonal aspects, melancholia, mania, or dysthymia. Most patients with major depression need pharmacotherapy, often in combination with psychotherapy. A number of therapeutic regimens using various antidepressant agents are available.

Pigmented skin lesions in black newborn infants.

Three findings from a study of one hundred black newborn infants examined for pigmented lesions are presented herein: significantly higher incidence than in prior neonatal examinations, a frequent clinical pattern of grouped macules, and an unusual histologic distribution of nevus cell theques. Fifty-one percent of the infants had congenital pigmented lesions. Biopsy specimens of thirty-two lesions were obtained, twenty-six showing histologic changes of lentigo, four melanocytic nevi (nevus-cell nevi), and two ephelides. Three of the four nevi were less than 1.5 cm in diameter and all were of the predominantly junctional type. Clinical appearance was not a consistent guide for classification in the newborn.

Serum methadone as an aid in managing methadone maintenance patients.

Serial serum methadone levels were obtained in two patients who were experiencing significant difficulties (including subjective and objective evidence of the opiate withdrawal syndrome) while on methadone maintenance. A precipitous drop in blood levels of methadone was recorded 2 to 6 hours after ingestion. It was during this same time period that withdrawal symptoms were most severe. When methadone was administered on a divided dosage regimen, there was a dramatic clinical improvement in both patients and a marked flattening of the curve of serum methadone levels. This pilot study suggests that the current practice of administering methadone as a single daily dose to all patients needs reconsideration; serial serum methadone levels may be helpful in determining which patients do better on a divided dosage regimen.

Pigmented lesions in newborn infants.

1058 newborn infants were examined. Forty-one (3-9%) had clinically discernible pigmented lesions compatible with melanocytic naevi. Biopsy was performed on thirty-four of the forty-one and of these; eleven, representing 1-01% of the infants, proved to be melanocytic naevi. No giant (garment) naevi were seen in this series. Two of the eleven naevi pathologically examined showed histological changes similar to those that have been reported in some giant naevi, but the remaining nine were not only different from criteria usually assigned to giant naevi, but they also differed from the usual adult naevi, in that most were predominantly junctional. None of the melanocytic naevi in this series showed any suggestion of malignant change. In newborn infants it is often impossible clinically to distinguish naevi from other types of pigmented lesions, as only eleven out of the thirty-four pigmented lesions were melanocytic naevi. Seven of the eleven melanocytic naevi were under 1-5 cm in diameter. No pigmented lesions were found on the palms, soles or genitalia.

The incidence of birthmarks in the neonate.

The presence of various types of birthmarks was determined in 1,058 newborn infants under 72 hours of age. Of these, 79.5% were white, 6.2% were black, 11.2% were ladinos, and 2.6% were Asiatic. Mongol spots were present in 9.6% of the white babies, 95.5% of the black babies, 81% of the Asiatic babies, and 70.1% of ladino infants. Pigmented lesions were present in 42 (4%) of the infants. Biopsies obtained in 34 (3.2%) revealed that only one-third (11) of these were melanocytic nevi. Salmon patches were present in 40.3% of the infants, recognizable early strawberry marks in 2.6%, and port-wine strains in 0.3%. In addition to birthmarks, it was determined that 30.3% of the 508 babies examined at one of the two hospitals had toxic erythema of the newborn.

Moles that cause concern.

It is strongly recommended that any pigmented lesion which cannot be diagnosed with certainty as benign should be excised and pathologically examined. In addition, any mole which is removed, no matter for what purpose, whether it is suspected of having malignant or premalignant changes or for cosmetic and functional purposes, should always be pathologically examined. If the lesion is suspected of showing malignant change, then if technically possible it should be completely excised. If the location is such, or if it is a sufficiently large lesion, that a simple complete excision cannot be performed at that time, then it is justifiable and good medical practice to do an incisional biopsy. However, if the pathological report shows that the tumor is malignant then the necessary radical surgery should be performed within 7 to 10 days of the initial biopsy. Under these circumstances, incisional biopsy does not adversely affect the prognosis. Under these circumstances, the incisional biopsy prevents unnecessary radical and sometimes mutilating surgery being performed for the treatment of a benign pigmented tumor.

Pigmented nevi. Induced changes in the junctional component.

The pigmented nevus represents a potentially more dynamic lesion than has been indicated by most published studies. New nevus cell clusters frequently appear in the epidermis over the residual portion of a nevus that remains after partial surgical excision. Even in relatively inactive nevi in adults, new junctional nevus cells may be induced by surgical trauma. This stimulated growth usually regresses by the time one year or more has elapsed. The growth of nevus cells is probably comparable to that induced in other cells by traumatic injury. There is no evidence to suggest that it is related to the development of melanoma in pigmented nevi.