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Biomedical subjects

J J Marx

Publications and source records attributed to J J Marx.

At least 19 recordsLinked to original sources
PubMed1992

Relevance of pretransfusion incubation of platelets at 37 degrees C.

The effect of pretransfusion incubation of platelets at 37 degrees C was assessed because of the controversial reports about its relevance. A dual-label technique (111indium and 114mindium) was applied in 10 healthy subjects receiving warmed and unwarmed autologous platelets simultaneously. Fresh platelet concentrates were infused into five subjects, whereas the other five subjects received stored platelet concentrates. The mean platelet volume decreased in all platelet concentrates during incubation, reflecting the restoration of the discoid shape of the platelets. The mean decrease was 0.35 fL (P = .003). However, the initial recovery and the mean platelet life-span were not improved by this procedure. It was concluded that there is no evidence that brief warming of platelets has any beneficial effect on platelet viability in healthy volunteers.

Adult↗
PubMed1992

Increased hydrogen peroxide concentration in human tumor cells due to a nitroxide free radical.

Evidence is presented that the nitroxide free radical, TEMPO, at concentrations commonly used to prevent oxidative damage, increases the intracellular hydrogen peroxide concentration. To investigate the origin of this increased hydrogen peroxide concentration, we have incubated various human tumor cell lines with compounds interfering with the generation of active oxygen metabolites. Sodium azide, inhibitor of the respiratory chain, the iron-chelating agent desferrioxamine, superoxide dismutase and catalase had no effect on the hydrogen peroxide concentration. Metyrapone, inhibitor of the cytochrome P450 system, was demonstrated to decrease, but not completely prevent, the hydrogen peroxide production. N-ethylmaleimide, a sulphydryl-bond alkylating agent, was able to completely prevent the increased hydrogen peroxide production. We conclude that, by increasing the cellular hydrogen peroxide concentration, TEMPO exerts a pro-oxidant effect. This increase in hydrogen peroxide production seems to be mediated by the induction of oxidase activity in the cytochrome P450 system, but other cellular systems involved in electron transport may also play a role.

Catalase↗
PubMed1992

Can the magnesium content of mononuclear blood cells be altered by oral magnesium supplementation?

A randomized, double-blind, placebo-controlled trial was performed on a rigorously defined group of normal subjects to see if magnesium (Mg) supplementation could affect serum Mg levels or Mg content of mononuclear blood cells. Forty-nine subjects were randomized to either placebo, tablets containing 90% United States recommended daily allowance (USRDA) of Mg, or tablets containing 180% USRDA of Mg. We were unable to demonstrate a statistically significant increase in Mg content of mononuclear blood cells.

Adult↗
PubMed1992

The effect of oral iron supplementation on erythropoiesis in autologous blood donors.

The effect of oral iron supplementation on erythropoiesis was studied prospectively in 34 autologous blood donors. The subjects, all of whom were to undergo total hip surgery, had normal iron status at the start of the study. During the preoperative period, in which 4 units of blood were collected, 17 patients received oral iron supplementation with 287 mg of ferrous sulfate (105 mg of elemental iron/day), while 17 patients did not use any iron supplementation. Oral iron supplementation during the 4-week preoperative period lessened the decrease in ferritin levels after two phlebotomies. Neither the decrease in hemoglobin nor the increase in erythropoietin levels was influenced by iron supplementation. In both iron-supplemented and control patients, serum erythropoietin levels returned to initial values within a few days after surgery. In autologous blood donors with a normal iron status, the use of supplemental iron does not affect erythropoiesis and is insufficient to maintain iron stores.

Administration, Oral↗
PubMed1992

Prevalence of antibody to Borrelia burgdorferi by indirect fluorescent antibody assay, ELISA, and western immunoblot in healthy adults in Wisconsin and Arizona.

The prevalence of antibody to Borrelia burgdorferi in healthy adults from Wisconsin and Arizona was determined by indirect fluorescent antibody assay (IFA), ELISA, and Western immunoblotting. A total of 301 sera from adult volunteer blood donors were collected from three areas of Wisconsin and compared with 49 consecutive anonymous adult volunteer donor sera from Tucson, Arizona, an area without reported Lyme borreliosis. Regional differences in seropositivity were found for Western immunoblotting (34[11%] of 301 from Wisconsin and none of 49 from Tucson; P less than .01) but not IFA or ELISA. No correlation was found among Western immunoblotting and IFA or ELISA results. For persons living in Madison or Milwaukee, Wisconsin (cities not endemic for Lyme borreliosis), 19 (86%) of 22 with a positive Western blot, but only 12 (48%) of 25 with a positive IFA or ELISA, had a significant exposure risk to B. burgdorferi-infected Ixodes dammini (odds ratio, 6.9; 95% confidence interval, 1.4-43.5). Western blot results were consistent with epidemiologic exposure to B. burgdorferi and implied frequent asymptomatic infection among healthy adults living in or visiting areas endemic for Lyme borreliosis.

Adult↗
PubMed1992

Relation between magnesium and potassium concentrations in myocardium, skeletal muscle, and mononuclear blood cells.

Potassium and magnesium were measured in 26 cardiac surgery patients (right atrial appendage), 23 autopsy subjects (right atrial appendage, left ventricular free wall, and skeletal muscle), and 9 healthy volunteers (mononuclear blood cells) to determine whether there was a relation between these two ions in the tissues measured. In the cardiac surgery patients, the potassium and magnesium concentrations were 46.35 +/- 3.89 and 4.40 +/- 0.58 (mean +/- SD, mumol/g wet weight tissue), respectively, and were significantly correlated (r = 0.54, P = 0.005). In the autopsy group, the respective concentrations were: for right atrial appendage, 30.54 +/- 10.18 and 3.66 +/- 0.70 mumol/g (r = 0.38, P = 0.14); left ventricular free wall, 60.69 +/- 17.93 and 7.74 +/- 1.73 mumol/g (r = 0.92, P = 0.0001); and skeletal muscle, 93.05 +/- 20.49 and 8.64 +/- 2.06 mumol/g (r = 0.91, P = 0.0001). In the healthy volunteer group, the results for potassium and magnesium in mononuclear blood cells were 42 +/- 9.9 and 3.99 +/- 0.70 fmol/cell, respectively (r = 0.94, P = 0.0001). Thus, potassium and magnesium concentrations were significantly correlated in all the tissues measured.

Aged↗
PubMed1991

Myocardial magnesium: relation to laboratory and clinical variables in patients undergoing cardiac surgery.

Magnesium concentration was measured in the right atrial appendage of 100 patients undergoing cardiac surgery and associations with serum and mononuclear blood cell magnesium, other laboratory values and patient clinical variables were studied. In addition, magnesium was measured in the right atrial appendage and left ventricular free wall in 23 autopsy subjects to determine whether there was a proportional relation between right atrial appendage and left ventricular free wall magnesium. The mean left ventricular free wall/right atrial appendage magnesium ratio was 2.13 +/- 0.39 (r = 0.67, p = 0.0009). In the group with cardiac surgery, the right atrial appendage magnesium concentration correlated inversely with age (r = -0.54, p = 0.001). The mean right atrial appendage magnesium concentration (micrograms/g wet weight tissue) was lower in patients with postoperative cardiac arrhythmia than in those without arrhythmia (103 +/- 13 versus 111 +/- 10, p = 0.009) and in diabetic than in nondiabetic patients (103 +/- 13 versus 109 +/- 12, p = 0.02). The right atrial appendage magnesium concentration also tended to be lower in patients receiving potassium/magnesium-losing diuretics, although this difference did not achieve statistical significance (105 +/- 14 versus 109 +/- 11, p = 0.16). Right atrial appendage magnesium concentration correlated positively with serum creatinine concentration (r = 0.31, p = 0.002) and negatively with serum calcium concentration (r = -0.29, p = 0.013). Serum magnesium did not correlate with right atrial appendage or mononuclear blood cell magnesium concentration or clinical variables. There was a statistically significant correlation between mononuclear blood cell and right atrial appendage magnesium concentrations in some subgroups of patients.

Aged↗
PubMed1991

A new dual-label technique for platelet survival studies with the use of 111indium and 114mindium tropolonate.

A dual-label technique to study the survival of two different populations of platelets within one individual was developed using 111indium and 114mindium. The validity of the technique was demonstrated in seven individuals with an expected equal survival time of two platelet populations and in two persons with an expected difference in platelet survival time. Since the energy spectra of the two indium isotopes are very close, a well-type germanium semiconductor detector was applied. By adaptation of the counting time the effective dose equivalent of the dual-label procedure could be restricted to 1.6 mSv. The dual-label technique provides an instrument for studying the survival of two different populations of platelets simultaneously within one individual.

Adult↗
PubMed1991

Iron metabolism in patients with the anaemia of end-stage renal disease during treatment with recombinant human erythropoietin.

Iron metabolism was studied in 21 patients with the anaemia of end-stage renal disease during 40 weeks of treatment with recombinant human erythropoietin (rhEPO). Oral iron was prescribed to all patients. Initial serum iron concentrations and transferrin saturation levels were subnormal, decreased during the correction period of treatment, and increased thereafter. In 81% of patients in whom pretreatment transferrin saturation was below 0.25, transferrin saturation decreased below 0.16, despite sufficiently high serum ferritin levels. Serum ferritin concentrations decreased significantly. There was no correlation between serum ferritin levels and serum iron or transferrin saturation. Ferrokinetic studies, performed before and during treatment, showed an increase in plasma iron turnover, in erythron transferrin uptake, and in the flux of iron binding sites through the plasma. The rhEPO dose needed to keep the haematocrit at the target level during the maintenance period of treatment was significantly correlated with transferrin saturation, and iron binding capacity, but not with serum ferritin concentrations. This suggests that the functional availability of iron in plasma, rather than the size of body iron stores, is a major factor in the determination of the response to rhEPO treatment in end-stage renal disease.

Adolescent↗
PubMed1991

Frequency and clinical significance of Lyme seropositivity in patients with isolated optic neuritis.

We evaluated antibody reactivity against Borrelia burgdorferi in 20 consecutive patients with newly diagnosed isolated optic neuritis who resided in a region endemic for Lyme disease. Four (20%) patients had positive serology. All three patients who had follow-up serologies showed rising convalescent levels of Borrelia-specific IgM. One patient refused lumbar puncture, one had normal CSF constituents except for an elevated Lyme antibody index, and two had CSF lymphocytic pleocytosis that remained unexplained after extensive evaluations for causes other than Lyme disease. We treated both patients who had CSF pleocytosis with intravenous ceftriaxone; the pleocytosis and optic nerve function improved. The other two patients received oral antibiotics and showed excellent recovery of visual acuity. We believe that serologic testing for Lyme disease is warranted for individuals with optic neuritis who reside in an endemic region, and patients with rising convalescent antibody levels or unexplained CSF pleocytosis should receive antibiotic treatment for Lyme disease.

Adolescent↗
PubMed1991

Diagnostic dilemma for the 1990s: Lyme disease versus rheumatic fever.

A 15-year-old boy developed an annular erythematous skin rash, fever, knee pain, syncope, and was found to be in complete heart block requiring temporary transvenous pacing. His recovery was complete following therapy with high dose steroids, aspirin, and IV ceftriaxone followed by oral penicillin. Serologic tests documented diagnostic levels of antibodies to Borrelia burgdorferi as well as to Group A streptococcal DNase B. Diagnoses of both Lyme disease and rheumatic fever are based on clinical presentation and serologic confirmation. Our patient had a clinical presentation compatible with either diagnosis and serologic test results suggestive of infection by both B burgdorferi and Group A streptococci. The patient's management was aimed at preventing complications of both diseases, since clinicians involved with the patient's case could not agree on the most likely diagnosis. We present this case to emphasize the following: both rheumatic fever and Lyme disease should be considered in patients presenting with annular skin rashes and complete heart block; serologic studies may be confusing in both Lyme disease and rheumatic fever since neither is entirely sensitive nor specific and efforts should be made to document the causative organism by appropriate cultures, biopsies, and stains when possible; and improved immunoserologic testing for Lyme disease, in particular, is highly needed.

Adolescent↗
PubMed1991

House dust mites in the West Indies.

The purpose of this study was to determine the role of the house dust mite. Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df), in allergic diseases on the island of St. Lucia. Dust samples were taken from living quarters of patients and hospital volunteers. The level of Df antigen in these living quarters was measured by RAST inhibition. All samples showed Df antigen within a large range of values. Prick tests were done to house dust mite and molds on 91 patients with suspected allergic disease with 63 (69%) reacting to at least one antigen. Of these, 56 (88.9%) reacted to one or both mites. House dust mite is a major allergen in St. Lucia.

Adolescent↗
PubMed1991

Dermatophagoides farinae allergen levels from two different sources within the same home: evaluation of two different collection techniques.

The allergens produced by the dust mites of the Dermatophagoides genus are now recognized as one of the major allergens in house dust. Quantification of those allergens helps to evaluate the effectiveness of avoidance measures and specific treatments aimed at the reduction of the mites and their allergens. The present study was undertaken to compare the level of D. farinae allergen collected by a standard vacuum cleaner with a disposable bag and the level of allergen collected by a hand-held vacuum equipped with a special filter. Samples were obtained from the main living area of 18 homes of patients allergic to D. farinae. Using a hand-held vacuum especially equipped with a removable micropore filter, a 2-m2 area of carpet was vacuumed for two minutes and an identical sample was collected from the major upholstered piece of furniture in the room. A third sample was obtained with an upright vacuum fitted with a clean disposable bag. The dust collected was extracted in phosphate buffered saline and resultant extracts were assayed for D. farinae allergen content by microtiter plate RAST inhibition assay. Results from these assays showed a large interhome variability regardless of sampling technique, but intrahome sampling showed remarkable consistency. A linear regression analysis demonstrated all of the comparisons correlated at a probability level of P less than .05. We conclude that dust mite allergen levels collected in a disposable bag vacuum cleaner are reliable indicators of the level of house dust mites present in the homes of patients.

Allergens↗
PubMed1990

Cohort studies of immunologic lung disease among Wisconsin dairy farmers.

Traditionally, hypersensitivity pneumonitis (HP) or farmer's lung disease (FLD) was thought to be the major occupational respiratory problem of farmers. In recent years, other acute conditions, particularly organic dust toxic syndrome (ODTS), have been recognized as significant features of the agricultural respiratory disease picture. The differences between HP and ODTS are discussed in this article. A cohort of workers on 90 dairy farms has been under study since 1975. Prevalence of FLD was calculated at 4.2/1,000. Extensive immunologic testing of this group was conducted. Serum antibody reactivity to farmer's lung antigens was related to chronic symptoms of bronchitis and occupational asthma, but not FLD. Serology may be thought of as a measure of exposure, but not FLD.

Agricultural Workers' Diseases↗
PubMed1990

Bacterial iron enhances oxygen radical-mediated killing of Staphylococcus aureus by phagocytes.

It has been shown that increasing bacterial iron concentration enhances killing by hydrogen peroxide (H2O2) but not by polymorphonuclear granulocytes (PMN). It is possible that owing to the multiple bactericidal mechanisms of the PMN, differences in the killing rate of iron-loaded bacteria and control bacteria are obscured. We decided, therefore, to compare the killing of iron-loaded bacteria with that of control bacteria using human monocytes (MN), PMN, and PMN-derived cytoplasts. Incubation of Staphylococcus aureus with increasing concentrations of ferrous ammonium sulfate (0 to 1,000 microM) progressively increased the iron content in the bacteria (from 0.01 to 0.24 mumol of iron per 10(9) bacteria). Iron loading of the bacteria markedly increased their susceptibility to killing by H2O2. After 1 h of incubation with 1 mM H2O2, 95 +/- 2% of the iron-loaded bacteria were killed compared with 18 +/- 4% of the control bacteria (P less than 0.0001). Iron loading of bacteria did not alter their susceptibility to killing by human PMN. However, iron-loaded bacteria were more susceptible to killing by MN (after 12 min of incubation, 81 +/- 2 versus 74 +/- 2% killing; P less than 0.008) and to killing by PMN-derived cytoplasts (after 60 min of incubation, 52 +/- 8 versus 33 +/- 5%; P = 0.003) than the controls. Moreover, iron loading enhanced luminol-mediated chemiluminescence of MN, PMN, and PMN-derived cytoplasts. The hydroxyl radical scavenger thiourea inhibited H2O2-mediated killing of iron-loaded staphylococci as well as luminol-mediated chemiluminescence. These results suggest that alterations in intrinsic iron content increase killing of staphylococci by H2O2, MN, and PMN-derived cytoplasts by a free radical-mediated mechanism.

Blood Bactericidal Activity↗
PubMed1990

The prevalence of Borrelia burgdorferi seropositivity in an area endemic for Lyme disease.

We conducted a seroprevalence survey of antibodies to Borrelia burgdorferi in West Central Wisconsin, an area endemic for Lyme disease. One hundred and thirty-seven of 153 patients having blood drawn at the Eau Claire Family Medicine Clinic and the associated rural Augusta practice participated in the study and were tested for the presence of antibodies to B burgdorferi and questioned about Lyme disease risk factors. An enzyme-linked immunosorbent assay showed that 15 (10.9%) of the 137 persons had serological evidence of exposure to B burgdorferi. None of these 15 persons reported a past or current history of clinical Lyme disease, and they were not found to have more symptoms commonly associated with Lyme disease than seronegative patients. We conclude that the prevalence of positive Lyme serologies in this area is similar to that of other endemic areas and that subclinical or asymptomatic infection probably accounts for many of these positive results.

Adolescent↗