The relationship of tibial bone perfusion to pain in knee osteoarthritis.

OBJECTIVE: To confirm altered perfusion within tibial bone marrow lesions (BMLs) and improve our understanding on the relationship between BMLs and pain in knee osteoarthritis (OA). METHODS: Participants with moderate to severe knee OA were recruited and pain was assessed using the pain subscale of the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Subchondral tibial BMLs were identified and graded on magnetic resonance imaging (MRI) proton density-weighted (PDW) fat suppressed images. A pharmacokinetic model was used to analyze perfusion parameters on dynamic contrast enhanced (DCE) MRI which represent transfer rates in and out of the BMLs. The relation between perfusion and pain was evaluated using multivariable linear regression after adjustment for BML grade, age, gender and body mass index (BMI). RESULTS: There were 37 participants (mean age 64.9 years, range 46-86) with radiographic Kellgren and Lawrence grades of 3 and 4 in the study knee; 75.6% had BMLs that were classified grades 1 and 2. The mean WOMAC pain score was 10.3 (0-20 scale). There was a significant correlation between BML K(el) (rate of contrast elimination) and BML grade (P = 0.001 univariate, P = 0.002 multivariate analyses), although we did not demonstrate any significant multivariate association between BML perfusion and pain. We also found an inverse relationship between pain at sleep and BML grade (P < 0.05). CONCLUSIONS: The absence of any significant association between bone perfusion and pain implies that the relationship of tibial BMLs to pain in OA is still incompletely understood. BMLs are just one component of the whole knee joint and are formed from various causes, all of which interact and collectively contribute to the genesis of pain in OA.

Five novel RPGR mutations in families with X-linked retinitis pigmentosa.

X-linked forms of retinitis pigmentosa (XLRP) are among the most severe because of their early onset, often leading to significant visual impairment before the fourth decade. RP3, genetically localized at Xp21.1, accounts for 70% of XLRP in different populations. The RPGR (Retinitis Pigmentosa GTPase Regulator) gene that was isolated from the RP3 region is mutated in 20% of North American families with XLRP. From mutation analysis of 27 independent XLRP families, we have identified five novel RPGR mutations in 5 of the families (160delA, 789 A>T, IVS8+1 G>C, 1147insT and 1366 G>A). One of these mutations was detected in a family from Chile. Hum Mutat 17:151, 2001.

Delayed presentation of abdominal bleeding in a teenage boy after a fall.

The delayed presentation of an abdominal bleed in a victim of a fall is a rare occurrence. In the multiple injured patients, even with an intact sensorium, competing pain from associated injuries may mask the pain from a occult injury. Although a rare occurrence of abdominal injury in an asymptomatic neurologically intact patient, in the patient requiring a computed tomography scan of a spinal fracture, it may be worthwhile to image the abdomen and pelvis as well to rule out a concomitant occult abdominal injury. Current literature regarding injuries associated with falls from height are discussed that support this position and the delayed manifestation of an abdominal bleed in a 17-year-old boy 1 day after a fall is presented.

Impact of early dietary intake and blood lipid composition of long-chain polyunsaturated fatty acids on later visual development.

BACKGROUND: In contrast to human milk, current infant formulas in the United States do not contain omega3 and omega6 long-chain polyunsaturated fatty acids. This may lead to suboptimal blood lipid fatty acid profiles and to a measurable diminution of visual function in developing term infants. The need for docosahexaenoic acid and arachidonic acid supplementation in the infant diet was evaluated in a double-blind, randomized clinical trial. METHODS: Healthy term infants were randomized to diets of (1) commercial formula, (2) docosahexaenoic acid-enriched formula (0.35% of total fatty acids), or (3) docosahexaenoic acid- (0.36%) and arachidonic acid- (0.72%) enriched formula. Eighty-seven infants completed the 17-week nutritional trial, and 58 were observed until 52 weeks of life. A reference group was exclusively breast fed for at least 17 weeks (n = 29). Outcome measures included electroretinographic responses, visual evoked potentials, and blood fatty acid analysis in infants at birth and at 6, 17, and 52 weeks of age. RESULTS: Commercial formula-fed infants had 30% to 50% lower content of docosahexaenoic acid in total red blood cell lipids during the 17-week feeding trial compared with breastfed infants. Significant differences persisted at the 1-year follow-up. Arachidonic acid content was consistently reduced in the commercial formula group by 15% to 20%. Infants fed long-chain polyunsaturated fatty acid-enriched formulas had docosahexaenoic acid and arachidonic acid blood lipid profiles resembling those of human milk-fed infants. Infants receiving this enriched formula had more mature electroretinographic responses than commercial formula-fed infants at 6 weeks of age. Human milk-fed and docosahexaenoic acid-enriched formula-fed infants had better visual acuity than commercial formula-fed infants at both 17 and 52 weeks of age. Early (17-week) fatty acid profiles in blood lipids were correlated with later (52-week) visual function development in study infants. CONCLUSIONS: Results from this clinical trial demonstrate that long-chain polyunsaturated fatty acid supplementation of formula in term infants produces blood lipid fatty acid profiles that are similar to those observed in breast-fed infants. This supplementation leads to better visual function later in life (i.e., 1 year of age) than that shown by infants fed commercial formula.

Inhibition of LDL oxidation by melatonin requires supraphysiologic concentrations.

Melatonin has been suggested as a potent antioxidant that may protect against development of atherosclerosis and cancer; however, these effects are unproven and controversial. The antioxidant capacity of melatonin was tested in comparison with alpha-tocopherol, ascorbic acid, and the melatonin precursors tryptophan and serotonin, by measuring inhibition of metal ion-mediated and human macrophage-mediated oxidation of LDL. Melatonin had weak antioxidant activity that was detectable only at concentrations 10000- to 100000-fold higher than physiologic concentrations. These results were comparable with published data showing that the radical scavenging activity of melatonin requires markedly supraphysiologic concentrations. In contrast, alpha-tocopherol was 50- to 100-fold more potent and was efficacious at physiologic concentrations. Ascorbic acid and tryptophan also were active at physiologic concentrations and were significantly more potent than melatonin. In summary, extremely supraphysiologic concentrations of melatonin had only weak antioxidant activity, which was surpassed by alpha-tocopherol, ascorbic acid, and tryptophan.

Differential effects of subcutaneous estrogen and progesterone on low-density lipoprotein size and susceptibility to oxidation in postmenopausal rhesus monkeys.

OBJECTIVE: To study the differential effects of subcutaneous E2 alone or in combination with P on the susceptibility of low-density lipoprotein (LDL) cholesterol to oxidation in naturally postmenopausal diet-controlled rhesus monkeys. DESIGN: Prospective, longitudinal controlled study. SETTING: Oregon Health Sciences University, Portland, Oregon, and Oregon Regional Primate Research Center, Beaverton, Oregon. PATIENT(S): Five naturally postmenopausal rhesus monkeys. INTERVENTION(S): Estradiol was administered subcutaneously for the first 4 weeks, followed by E2 plus P for 4 weeks, followed by a third 4-week washout period. MAIN OUTCOME MEASURE(S): Changes in plasma lipoprotein levels and oxidation of LDL and serum concentrations of E2 and P. RESULT(S): Levels of LDL cholesterol fell after 4 weeks of treatment with E2, compared with baseline. The lag time to half maximal light absorbancy after 4 weeks of E2 treatment was significantly increased compared with baseline. The maximal absorbance values and the slope of the propagation phase after 4 weeks of treatment with E2 were decreased compared with baseline. After 4 weeks of combined E2 and P treatment, all values were comparable to baseline. CONCLUSION(S): These results suggest that subcutaneous E2 therapy appears to enhance LDL resistance to oxidation and that this effect is attenuated by the addition of the P.

Reduction of dopamine beta-monooxygenase. A unified model for apparent negative cooperativity and fumarate activation.

The interactions of reductants with dopamine beta-monooxygenase (DbetaM) were examined using two novel classes of reductants. The steady-state kinetics of the previously characterized DbetaM reductant, N,N-dimethyl-1,4-p-phenylenediamine (DMPD), were parallel to the ascorbic acid-supported reaction with respect to pH dependence and fumarate activation. DMPD also displayed pH and fumarate-dependent apparent negative cooperativity demonstrating that the previously reported cooperative behavior of DbetaM toward the reductant is not unique to ascorbic acid. The 6-OH phenyl and alkylphenyl-substituted ascorbic acid derivatives were more efficient reductants for the enzyme than ascorbic acid. Kinetic studies suggested that these derivatives behave as pseudo bisubstrates with respect to ascorbic acid and the amine substrate. The lack of apparent cooperative behavior with these derivatives suggests that this behavior of DbetaM is not common for all the reductants. Based on these findings and additional kinetic evidence, the proposal that the apparent negative cooperativity in the interaction of ascorbic acid with DbetaM was due to the presence of a distinct allosteric regulatory site has been ruled out. In contrast to previous models, where fumarate was proposed to interact with a distinct anion binding site, the effect of fumarate on the steady-state kinetics of these novel reductants suggests that fumarate and the reductant may interact with the same site of the enzyme. In accordance with these observations and mathematical analysis of the experimental data, a unified model for the apparent negative cooperativity and fumarate activation of DbetaM in which both fumarate and the reductant interact with the same site of all forms of the enzyme with varying affinities under steady-state turnover conditions has been proposed.

Analysis of the expression and immunostimulatory capacity of class I major histocompatibility antigens on rat trophoblast cell lines.

In rat strains expressing the a and other major histocompatibility complex (MHC) haplotypes, subpopulations of placental trophoblast cells synthesize the nonclassical class I Pa antigen in preference to the classical RT1.Aa antigen. In this study, a rat trophoblast cell line, R8RP.3, which was derived from midgestation placentas of PVG.R8 (RT1.Aa) rats, was shown to express class I antigens similarly to those of trophoblast cells in situ. Both unstimulated and IFN-gamma-exposed metabolically labeled R8RP.3 cells synthesized more Pa than RT1.Aa antigen. The reverse was true for labeled spleen cells from PVG.R8 rats. The R8RP.3 cells failed to stimulate allogeneic lymphocyte proliferation even when high levels of both classical and nonclassical class I MHC antigens were expressed on their membranes after incubation with IFN-gamma. These experiments thus supply the first evidence that the inductive phase of the immune response is not promoted by trophoblast cell class I MHC antigens, which could explain the failure of mothers to mount immune responses to class I MHC positive trophoblast cells.

Products of lipopolysaccharide-activated macrophages (tumor necrosis factor-alpha, transforming growth factor-beta) but not lipopolysaccharide modify DNA synthesis by rat trophoblast cells exhibiting the 80-kDa lipopolysaccharide-binding protein.

Pregnancy losses from gram negative bacterial infections could be caused by direct effects of LPS on placental cells, or indirectly via LPS activation of macrophages in the uteroplacental unit. To evaluate those alternatives, LPS, LPS-activated peritoneal cells, conditioned medium from LPS-activated peritoneal cells, and some purified and recombinant molecules known to be secreted by activated macrophages were tested for their abilities to modify DNA synthesis by rat trophoblast cells. Three trophoblast cell lines derived from midgestation placentas of outbred and inbred rats were used for the experiments. Although the 80-kDa LPS-binding protein was demonstrated on trophoblast cells, LPS alone had no effect on the ability of trophoblast cells to synthesize DNA. In cocultures, trophoblast cell DNA synthesis was slightly enhanced by low concentrations of both unstimulated and LPS-activated peritoneal cells. At higher concentrations, LPS-activated cells caused significant inhibition of DNA synthesis by trophoblast cells. Conditioned media from LPS-activated peritoneal cells were highly inhibitory to trophoblast cell DNA synthesis. When specific molecules likely to be components of those media were tested, IL-1 was found to have a modest but reproducible stimulatory effect and PGE2 did not change trophoblast cell incorporation of [3H]TdR. In contrast, trophoblast cell DNA synthesis was markedly inhibited in a dose-dependent manner by both TNF-alpha and TGF-beta 1. No differences in the sensitivity of trophoblast cells from outbred and inbred rats were observed. Given the limitations of the experimental model system, the results suggest that in cases of infection by gram-negative bacteria LPS may have an adverse effect on pregnancy by stimulating resident macrophages to generate and release molecules that are inhibitory to trophoblast cell DNA synthesis.

Airway secretory IgA concentrations in patients with lung cancer. Evaluation of the uninvolved lung.

To determine whether concentrations of the primary airway immunoglobulins (SIgA, IgG) are altered in the uninvolved lung of patients with lung cancer, we determined concentrations of SIgA and IgG in bronchial washings recovered from a proximal airway of the uninvolved lung in 24 patients with lung cancer and in ten patients with benign lung disease. When standardized for the amount of total protein recovered (SIgA/TP, IgG/TP), bronchial washings recovered from the uninvolved lung of lung cancer patients demonstrated a significantly decreased SIgA/TP ratio compared to control subjects (.14 +/- .02 vs .31 +/- .05, SEM, p less than 0.05). There were no differences in the IgG/TP ratios. Lung cancer patients with a decreased serum albumin (less than 3.2 g/dl) had a significantly decreased SIgA/TP ratio in bronchial washings compared to patients with a higher serum albumin (.08 +/- .03 vs .18 +/- .04, SEM, p less than 0.05). The decreased relative concentration of airway SIgA in lung cancer patients may adversely affect airway defenses against bacterial colonization.

Isolation of phenotypically distinct trophoblast cell lines from normal rat chorioallantoic placentas.

Growth characteristics and the expression of trophoblast-associated markers by six cell lines generated from midgestation chorioallantoic placentas of outbred (Holtzman) and inbred (Lewis, PVG.RT Ir8) rats were evaluated. The cells comprising all cell lines were epithelioid (contained cytokeratin-type intermediate filaments), had normal (2n, 4n) DNA content, and synthesized the extracellular matrix glycoprotein laminin. Variability was observed among the lines in all other characteristics: median cell size, rate of growth, serum dependency, responses to transferrin and dibutyryl cyclic adenosine-3',5'-monophosphate, synthesis of some major proteins, alkaline phosphatase activity, and the expression of immunoreactive placental lactogen-II. In general, cell lines with smaller mean cell sizes grew rapidly and required little serum for maintenance in vitro; cell lines with larger mean sizes grew more slowly and preferred higher concentrations of serum. Some associations between mean cell size/rate of growth and other characteristics were observed. No major differences were apparent between cell lines generated from outbred and inbred rat placentas. Trophoblast cell lines expressing distinct phenotypes provide a valuable new approach for studying a wide range of trophoblast cell activities.

Lymphocyte subsets in lung cancer.

Altered cellular immune function has been demonstrated in patients with lung cancer, including decreased numbers of circulating lymphocytes and changes in the percentage of lymphocytes in various functional subsets. We quantitated lymphocyte subsets in 54 patients with lung cancer including patients with limited (stages 1 and 2) nonsmall cell lung cancer (NSCLC, n = 23), advanced (stage 3) NSCLC (n = 16), and small cell cancer (SCLC, n = 15). Serum albumin was decreased in 15 lung cancer patients, and lymphocyte subsets were separately evaluated in these patients. Lymphocyte populations in cancer patients were compared to those of nonsmokers and a smoking patient population. No difference from smokers was noted in patients with limited NSCLC. Patients with SCLC and advanced NSCLC had significantly decreased numbers of T-helper and T-suppressor cells (p less than 0.05). Patients with lung cancer and hypoalbuminemia had the greatest decrease in number of circulating T-helper cells (p less than 0.001). B-lymphocytes were also decreased in patients with advanced NSCLC and patients with hypoalbuminemia (p less than 0.05). A decrease in population of T-lymphocytes subsets is frequent in patients with SCLC, advanced NSCLC, and lung cancer patients with hypoalbuminemia.

A mimicking red blood cell autoantibody accompanying transfusion and alloimmunization.

A patient with sickle cell disease who concomitantly developed red cell autoimmunity and alloimmunization is reported. The implied but 'wrong' specificity of the autoantibody mimicked one of the alloantibodies in the patient's serum. Although the patient's red blood cells phenotyped at Ro4, anti-rh" was eluted from them on several occasions. Absorption and secondary elution from selected cells proved the cell bound antibody had a unique and independent specificity from the anti-rh" in his serum. Standard antibody identification procedures did not distinguish these differences.