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Biomedical subjects

J A Mark

Publications and source records attributed to J A Mark.

8 recordsLinked to original sources
PubMed1995

Soluble transferrin receptor as an index of iron status in Zaïrian children with malaria.

This study was designed to evaluate soluble transferrin receptor (sTfR) as an index of iron status in 0.5-16-year-old Zaïrian children: 17 with symptomatic malaria, 8 with asymptomatic malaria, and 15 controls. sTfR was also measured in 20 plasma samples obtained from iron sufficient laboratory employees. sTfR, haemoglobin and ferritin were measured by enzyme-immunoassay, cyanmethaemoglobin method, and radioimmunoassay respectively. Mean haemoglobin levels were lower and ferritin higher (P < 0.001) in children with clinical symptoms of malaria than in those without malaria, and they were intermediate in those with asymptomatic malaria. Mean sTfR concentrations were similar among the three groups of children and laboratory controls. There was a considerable overlap in sTfR concentrations between the three groups of children (1.8-10.2, 2.9-11.6 and 2.97-8.95 mg 1(-1) in symptomatic malaria, asymptomatic malaria and control groups, respectively) as well as laboratory controls (1.2-7.30 mg l-1). Despite the overlap, 6 children with malaria (24%) and one control child (6.7%) had sTfR concentrations above the highest concentration found in laboratory controls. No child had serum ferritin < 12 micrograms l-1 (suggestive of iron deficiency). As expected, sTfR negatively correlated with ferritin (r = -0.230) in the overall study population of children, and with haemoglobin in children with asymptomatic malaria (r = -0.943, P < 0.05), as well as in control children (r = -0.363). All children with sTfR above normal were also anaemic. Although the upper limit of normal sTfR concentration in healthy children is unknown, using the cut-off value of adults, we conclude that sTfR might be a more sensitive index of iron deficiency than serum ferritin in patients with malaria.

Adolescent↗
PubMed1994

Airline advisory nursing.

The commercial airliner cabin is a specialized environment, usually pressurized to an equivalent of 2,438-meter pressure altitude. Such an altitude can adversely affect people prone to hypoxia. Preflight attention to this and other problems by an advisory nurse (AN) can minimize or prevent in-flight emergencies. The AN can also facilitate travel for passengers with medical needs by being familiar with airline policies and federal regulations. By educating the patient/passenger, health care providers and airline personnel, the safety, comfort and dignity of all concerned can be maximized.

Air Ambulances↗
PubMed1993

Preflight medical screenings of patients. Analysis of health and flight characteristics.

We evaluated the demographic, medical, and flight characteristics of 1,115 passengers who were routinely referred for preflight medical screening by a major domestic air carrier. The largest category consisted of 892 patients who requested in-flight oxygen therapy for cardiopulmonary conditions, of which COPD and cardiac disorders were the most frequent indications; 561 of these patients were 60 years or older. Overall, 386 passengers were recently hospitalized, 911 were using medications, 657 were receiving oxygen therapy, and 761 had flown previously. In the group using in-flight oxygen therapy, the average flight duration was 236 min and layover time, 87 min. These findings indicate that large numbers of patients undergoing preflight screening are receiving medication and have a wide range of medical diagnoses and variable health status. We conclude that preflight medical screening and counselling can be important and helpful in assuring safe and comfortable air travel in this patient population.

Adult↗
PubMed1992

Tin-protoporphyrin-mediated disruption in vivo of heme oxygenase-2 protein integrity and activity in rat brain.

The ability of synthetic metalloporphyrins to suppress heme oxygenase activity and bilirubin formation has recently become of considerable clinical and experimental interest for suppression of jaundice in humans, including neonatal hyperbilirubinemia. The present investigation compares the biochemical effects of Sn- and Zn-protoporphyrins on the predominant heme oxygenase isozyme present in the brain (HO-2) at activity, protein, and transcript levels and describes the ability of Sn-protoporphyrin to adversely affect this isozyme. Specifically, 6 h after a modest dose (50 mumol/kg, i.v.) of Sn-protoporphyrin, heme oxygenase activity in rat brain was nearly undetectable. In addition, as revealed by Western blot analysis, HO-2 protein level was decreased by 20% and the electrophoretic behavior of the protein in the microsomal membranes was altered. Moreover, the activity of NADPH-cytochrome P-450 reductase, which is required for the oxidation of heme molecule, was markedly decreased (60% of control). Western immunoblot analysis revealed also a pronounced decrease in the reductase protein level. The inducible form of heme oxygenase, HO-1, was not detectable by immunoblotting in brain microsomes of either control or Sn-protoporphyrin-treated animals. Northern blot analyses did not reveal decreases in the levels of the single HO-1 mRNA (1.8 kb) or the two HO-2 transcripts (1.3 and 1.9 kb), suggesting that Sn-protoporphyrin mediates its effects on heme oxygenase isozymes at the protein level. Zn-protoporphyrin, on the other hand, had no deleterious effect on brain parameters presently investigated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Plasmacytoma of the urethra treated with transurethral resection and radiotherapy.

Plasmacytoma, which is a localized malignant plasma cell tumor, occurs rarely and is found mostly in the upper airways of older patients. Two urethral plasmacytomas have been reported, 1 of which was a primary lesion. We describe a primary plasmacytoma of the urethra in a 23-year-old woman who had been exposed to diethylstilbestrol in utero. The patient underwent transurethral resection of the tumor and radiation therapy and has been free of disease for more than 10 years.

Adult↗
PubMed1978

Comparison of antigenic heterogeneity of Neisseria gonorrhoeae strains by micro-immunofluorescence and serum bactericidal tests.

The antigenic heterogeneity of Neisseria gonorrhoeae strains was assessed by the micro-immunofluorescence (micro-IF) and the serum bactericidal tests. The micro-IF test verified the antigenic heterogeneity of nine strains received from the Center for Disease Control and placed them into immunotypes A and B. The serum bactericidal system also detected different antigenic determinants among the strains. Although the micro-IF and bactericidal assays did not correspond in each instance, the overall pattern of similarities and differences among these gonococcal strains was similar. The micro-IF pattern obtained with mouse antisera was identical to the pattern revealed with guinea pig antisera. Different colony type organisms showed similar sensitivity in the bactericidal test. The micro-IF test is a rapid technique for the immunotyping of N. gonorrhoeae and has the additional advantages of reproducibility and simplicity.

Animals↗