Biomedical subjects

J Carlson

Publications and source records attributed to J Carlson.

At least 109 records · Page 6Linked to original sources

PubMed1998

Suggested ultrasound parameters for the assessment of fetal well-being during chronic hemodialysis.

There are no published guidelines on how to assess fetal well-being during hemodialysis. We have developed a specific protocol of renal and obstetric interventions to ensure that hemodialysis is associated with minimal changes in fetal status. We tested this protocol serially over a 9-week period in a pregnant patient who was undergoing chronic hemodialysis for end-stage renal disease. Testing involved serial assessments of uterine and umbilical artery blood flow with Doppler velocimetry and continuous fetal heart rate tracings, before, during and after each hemodialysis session. We found that, by strict adherence to these guidelines, there were no significant alterations in maternal mean arterial blood pressure, continuous fetal heart rate tracings, uterine artery systolic/diastolic ratios, or umbilical artery systolic/diastolic ratios. We conclude that stable uteroplacental and fetal perfusion can be maintained during chronic hemodialysis in pregnancy by adhering to a specific set of precautions.

Adult↗

PubMed1998

Quality of life and productivity in nurses reporting migraine.

A random sample survey was conducted to determine the prevalence of migraine in nurses and to study its effect on quality of life and productivity. Of the 10,000 nurses sampled, 2949 returned the questionnaire for a response rate of 29.5% The majority (99%) of respondents were employed and worked in hospitals (60%). According to the International Headache Society (IHS) criteria, 17% of the sample (n=495) were classified as having migraine. An additional 25% (n = 750) suffered severe headaches but did not meet IHS criteria for migraine, and the remaining 58% (n = 1704) were classified as not having either migraine or severe headaches. The migraineurs had significantly reduced work productivity and quality of life compared to both the severe headache and the nonmigraine nonsevere headache groups. This study will increase awareness and sensitivity of the profession to its colleagues who are migraine sufferers.

Adult↗

PubMed1998

Pain management issues: the cost of medications in rural settings.

Cost of analgesic and adjuvant medications used by rural patients with cancer cared for by 29 nurses participating in an in-depth education program were evaluated before and after the program. Across all time periods, the median daily cost was $5.16 across all medications. Average daily cost and maximum and median cost of all medications were $5.36, $74.38 and $3.58, respectively. Average daily cost did not change over time. Average pain intensity did not change over time and was not related to prescribing patterns or daily costs. While professional education was demonstrated to produce change in prescribing practices, further research is needed to evaluate patterns of medication administration and effectiveness patterns using reliable outcome measures other than self report of pain intensity.

Adult↗

PubMed1998

Separation of aromatic acids, DOPA, and methyl-DOPA by capillary electrophoresis with dendrimers as buffer additives.

Polyamidoamine starburst dendrimers with terminal carboxylate groups are used as a pseudo-stationary phase in electrokinetic chromatography for separating the selected aromatic amino acids phenylalanine, phenylglycine, homophenylalanine, and tyrosine and the catecholamines 3-(3,4-dihydroxyphenyl)alanine and 3-(3,4-dihydroxyphenyl)-2-methylalanine at different pH levels. A significant difference in analyte selectivity is observed between dendrimers of different generations and at different pH levels. At pH 7.0, the utility of the dendrimers for separating these analytes is limited by relatively low selectivity and a noisy baseline. However, good separation and selectivity are obtained with low generation dendrimers (G0.5 and G1.5) at low pH. Strong association of the solute with dendrimers is observed for high generations (G2.5, G3.5, and G5.5).

Biocompatible Materials↗

PubMed1998

Examination of the self-selected fluid intake practices by junior athletes during a simulated duathlon event.

Thirty-two elite junior athletes in two age categories, older than or equal to 15 years old (O15) (8 females and 9 males) and less than 15 years old (U15) (8 females and 7 males), performed a laboratory-based duathlon (run-ride-run). At the completion of the event, significant body mass losses were recorded for all groups. Compared with the other three groups, the O15 males lost body mass at a greater absolute rate (1.26 +/- 0.06 kg.hr-1 vs. a mean of 0.62 +/- 0.11 kg.hr-1 for the other three groups) and a greater relative rate (1.95 +/- 0.10%BM.hr-1 vs. a mean of 1.23 +/- 0.19%BM.hr-1 for the other three groups) (p < .05). No differences were observed between groups for fluid consumption. Subjects consumed more fluid (p < .05) during the cycle phase and postevent than preevent or during the run phases. Results indicated that the athletes' fluid intake practices were insufficient to maintain adequate hydration during the simulated event.

Adolescent↗

PubMed1998

Extensive immunoglobulin binding of Plasmodium falciparum-infected erythrocytes in a group of children with moderate anemia.

Immunoglobulins (Ig) from healthy, nonimmune individuals bind to the surfaces of Plasmodium falciparum-infected erythrocytes (RBC). In order to investigate the presence of this parasite phenotype in wild isolates and its potential association with malarial anemia, we conducted a study of 207 anemic or nonanemic children with malaria in Gabon. Surface Ig binding to infected RBC was detected for 83% of the isolates. No difference in Ig binding between the groups was observed, but all isolates which exhibited extensive Ig binding were found in a group of moderately anemic children.

Adolescent↗

PubMed1998

Age-related buildup of humoral immunity against epitopes for rosette formation and agglutination in African areas of malaria endemicity.

In this report, we show an age-related buildup of agglutinating activity as well as serum activity against rosette formation in children living in areas of Kenya and Gabon where malaria is endemic. Sera from Kenyans in general exhibited a stronger and wider immune response toward the epitopes, probably reflecting a difference in transmission patterns between the two areas. Thus, our results indicate that repeated malaria attacks in areas of endemicity, and consequently exposure to different isolate-specific antigens, will elicit an antibody-mediated response eventually enabling recognition of the majority of rosetting and agglutinating antigens. The correlation between antirosetting and agglutinating capacity was poor in individual cases, indicating that the rosetting epitopes are only a minor part of the highly diverse surface-exposed antigens (mainly PfEMP1) on the surface of parasitized erythrocytes toward which antibodies may react. These data together with our previous findings that the protection against cerebral malaria correlates with presence of antirosetting antibodies shed new light on our understanding of the gradual acquisition of immunity toward severe complications of malarial infection which children reared in areas of endemicity attain.

Adolescent↗

PubMed1998

Ultrasound enhanced thrombolysis in experimental retinal vein occlusion in the rabbit.

AIMS: To investigate if it was possible to lower the dose of streptokinase and maintain an effective thrombolysis by adding pulsed low energy ultrasound. METHODS: 53 retinal veins in 27 rabbits were occluded by rose bengal enhanced laser treatment. Six rabbits were treated with streptokinase (50,000 IU/kg), 10 rabbits were treated with a low dose of streptokinase (25,000 IU/kg), and 11 rabbits were treated with a low dose of streptokinase (25,000 IU/kg) and pulsed ultrasound during 1 hour. Fluorescein angiography was performed immediately before the thrombolytic treatment and after 12 hours. RESULTS: In the group treated with streptokinase (50,000 IU/kg) all vessels were open. In the group that was given streptokinase (25,000 IU/kg), 21% of the vessels were open. In the group that was treated with streptokinase (25,000 IU/kg) and ultrasound, 64% of the vessels were open. The difference between groups 2 and 3 is statistically significant (p = 0.011) CONCLUSION: Adding pulsed low energy ultrasound makes it possible to lower the dose of streptokinase while maintaining a good thrombolytic effect.

Animals↗

PubMed1998

Moderate exercise during growth in prepubertal boys: changes in bone mass, size, volumetric density, and bone strength: a controlled prospective study.

Cross-sectional studies of elite athletes suggest that growth is an opportune time for exercise to increase areal bone mineral density (BMD). However, as the exercise undertaken by athletes is beyond the reach of most individuals, these studies provide little basis for making recommendations regarding the role of exercise in musculoskeletal health in the community. To determine whether moderate exercise increases bone mass, size, areal, and volumetric BMD, two socioeconomically equivalent schools were randomly allocated to be the source of an exercise group or controls. Twenty boys (mean age 10.4 years, range 8.4-11.8) allocated to 8 months of 30-minute sessions of weight-bearing physical education lessons three times weekly were compared with 20 controls matched for age, standing and sitting height, weight, and baseline areal BMD. Areal BMD, measured using dual-energy X-ray absorptiometry, increased in both groups at all sites, except at the head and arms. The increase in areal BMD in the exercise group was twice that in controls; lumbar spine (0.61 +/- 0.11 vs. 0.26 +/- 0.09%/month), legs (0.76 +/- 0.07 vs. 0.34 +/- 0.08%/month), and total body (0.32 +/- 0.04 vs. 0.17 +/- 0.06%/month) (all p < 0.05). In the exercise group, femoral midshaft cortical thickness increased by 0.97 +/- 0. 32%/month due to a 0.93 +/- 0.33%/month decrease in endocortical (medullary) diameter (both p < 0.05). There was no periosteal expansion so that volumetric BMD increased by 1.14 +/- 0.33%/month, (p < 0.05). Cortical thickness and volumetric BMD did not change in controls. Femoral midshaft section modulus increased by 2.34 +/- 2. 35 cm3 in the exercise group, and 3.04 +/- 1.14 cm3 in controls (p < 0.05). The growing skeleton is sensitive to exercise. Moderate and readily accessible weight-bearing exercise undertaken before puberty may increase femoral volumetric BMD by increasing cortical thickness. Although endocortical apposition may be a less effective means of increasing bone strength than periosteal apposition, both mechanisms will result in higher cortical thickness that is likely to offset bone fragility conferred by menopause-related and age-related endocortical bone resorption.

Age Determination by Skeleton↗

PubMed1998

The time course of cytoadhesion, immunoglobulin binding, rosette formation, and serum-induced agglutination of Plasmodium falciparum-infected erythrocytes.

We describe morphologic characteristics of acridine orange-stained Plasmodium falciparum-infected erythrocytes and the sequential expression of several adhesion phenomena. In particular, we have studied when the adhesive and antigenic modifications appear on the infected erythrocyte surface that mediate binding to C32 melanoma cells (cytoadherence) or to erythrocytes (rosette formation) during a complete 48-hr life cycle of the parasite. The C32 melanoma cell binding started at about 12 hr and was seen during the whole life cycle with a peak around 28 hr (650 infected erythrocytes/100 C32 melanoma cells). Rosettes started to appear and immunoglobulin was found bound to the parasitized red blood cell (PRBC) somewhat later (16-20 hr). These adhesive events culminated at the mid-trophozoite/schizont stage (24-36 hr) with rosette formation and an immunoglobulin binding rate of about 50%, which decreased to about half of the peak values at the end of the life cycle. Serum-induced agglutination of the infected erythrocytes was also most extensive at 24-36 hr, but agglutination was seen with all late stage parasites, i.e., both trophozoites and schizonts at 24-48 hr of age. Taken together, adhesion to C32 melanoma cells starts prior to that of rosette formation, immunoglobulin binding, or serum-induced agglutination.

Agglutination Tests↗

PubMed1998

A comparison of role expectations and communication styles between transplant coordinators and transplant staff nurses.

The role of the transplant coordinator is multifaceted and demanding, requiring advanced clinical skills in addition to patient management responsibilities. Although much is known about the clinical skills of these coordinators, there is virtually no information available about their management abilities. A comparison of the beliefs of transplant coordinators and transplant staff nurses confirms that the coordinators have the role expectations and communication styles to allow them to function effectively in managing patient care as well as in working with physicians and other health professionals.

Adult↗

PubMed1998

Chiaroscuro hematopoietic stem cell.

These observations suggest several immediate clinical strategies. In gene therapy, approaches could be targeted to obtain cycling of hematopoietic stem cells and gene-carrying retrovirus vector integration followed by engraftment at an appropriate time interval which favors engraftment. The same type of approach can be utilized for stem cell expansion approaches. Alternatively marrow or peripheral stem cell engraftment can be obtained with minimal to no toxicity in allochimeric strategies in such diseases as sickle cell anemia or thalassemia. A similar approach could be useful in obtaining cell engraftment with minimal toxicity in therapies employing cellular immune (T-cell and NK-cell) attack against cancer. These areas of clinical application are outline in Table 3.

Animals↗

PubMed1998

Barriers to social services for HIV-infected urban migrators.

Anecdotal accounts suggest that residency requirements often lead to denial of services at a time when HIV positive migrators are most in need of these services. However, this suspicion has never been empirically tested. Using needs assessment data collected for Harris County, Texas, this article examines eligibility and knowledge barriers faced by HIV positive recent migrators into Harris County. Results indicated that migration into the county was a significant predictor of failure to receive government-administered basic services such as food services but was not a significant predictor of failure to receive community based organization (CBO)-administered "specialized" services targeted specifically to HIV positive individuals. Results also indicated that migration was associated with knowledge barriers for all types of services.

Adult↗

PubMed1998

Raised platelet levels in diabetes mellitus complicated with nephropathy.

OBJECTIVES: To study if elevated platelet levels are found in early and late diabetic nephropathy. DESIGN: A retrospective study was performed of platelet count in different subgroups of patients with insulin-dependent diabetes mellitus, including patients with long and short duration of diabetes and with early signs of nephropathy. Patients with severe renal failure subjected to renal transplantation were also included. RESULTS: The results suggest that raised platelet levels were associated with early signs of diabetic nephropathy and with female gender. Amongst diabetics progressing to uraemia leading to renal transplant, the platelet level was 50% higher than in non-diabetic uraemic patients. CONCLUSION: It is concluded that raised platelet levels are a common finding in patients with diabetes mellitus complicated by nephropathy.

Adult↗

PubMed1997

Patterns of feline coronavirus infection and fecal shedding from cats in multiple-cat environments.

OBJECTIVE: To determine, by use of a reverse transcriptase-polymerase chain reaction (RT-PCR) test, patterns of fecal shedding of feline coronavirus among cats. DESIGN: Prospective observational study. ANIMALS: 275 purebred cats from 6 private catteries and 40 specific-pathogen-free (SPF) laboratory-reared cats. PROCEDURE: 40 SPF cats were experimentally inoculated with crude fecal extract containing feline enteric coronavirus (FECV). Fecal and plasma samples were collected every 4 days and evaluated by use of RT-PCR and indirect immunofluorescence assays, respectively, to correlate RT-PCR results with fecal infectivity and to determine patterns of FECV shedding and anti-FECV IgG production in acutely infected cats. The 275 cats in private catteries were monitored for 1 year. Fecal and blood samples were collected every 1 to 3 months and assayed by use of RT-PCR and serologic tests to determine patterns of coronavirus shedding and cofactors for high frequency shedding. RESULTS: Results of the RT-PCR test in SPF cats were directly correlated with fecal extract infectivity. Overall, 370 of 894 (41%) fecal samples collected from cattery and shelter cats contained infectious levels of coronavirus. Of 121 cats from which multiple samples were collected, 11 never shed virus and 35, 65, and 10, respectively, shed virus with low, moderate, and high frequency. High frequency shedding was associated with age and cattery of origin, but not with sex or concurrent disease. Stress associated with parturition and lactation did not induce shedding in queens. Kittens did not shed coronavirus before they were 10 weeks old, even when nursed by shedding mothers. CLINICAL IMPLICATIONS: A large proportion of cats in multiple-cat environments shed coronavirus at any given time, but most undergo cycles of infection and shedding, recovery, and reinfection. Infection is acquired from chronically shedding cats and from infectious cats undergoing transient primary infection. Chronically shedding cats cannot be identified on the basis of antibody titer or signalment, but must be identified on the basis of the results of serial fecal RT-PCR tests.

Animals↗

PubMed1997

Risk factors for feline infectious peritonitis among cats in multiple-cat environments with endemic feline enteric coronavirus.

OBJECTIVE: To determine what risk factors, other than genetic predisposition, contribute to the incidence of feline infectious peritonitis (FIP) in private breeding catteries and animal shelters. DESIGN: Cats from 7 catteries and a shelter were observed monthly for 1 year. At each visit, cats were examined, fecal samples were collected for determination of feline coronavirus shedding, and blood samples were collected for determination of coronavirus antibody titers. Diagnostic tests were performed on all cats that died of FIP. ANIMALS: 275 purebred or random-bred cats that were kept by private breeder-owners in homes. RESULTS: 24 cats died of FIP during the study. Development of FIP was not associated with cattery, mean cat number, mean age, sex, cattery median coronavirus antibody titer, husbandry and quarantine practices, caging and breeding practices, or prevalence of concurrent diseases. However, risk factors for FIP included individual cat age individual cat coronavirus titer, overall frequency of fecal coronarvirus shedding, and the proportion of cats in the cattery that were chronic coronavirus shedders. Deaths from FIP were more frequent in fall and winter, and on the basis of analysis of cattery records, the number of deaths varied yearly. Epidemics (> 10% mortality rate) were reported at least once in 5 years in 4 catteries. CLINICAL IMPLICATIONS: Elimination of FIP from a cattery is only possible by total elimination of endemic feline enteric coronavirus (FECV) infection. The most important procedure to reduce FECV from catteries is elimination of chronic FECV shedders.

Age Factors↗

PubMed1997

Calcium binding to tandem repeats of EGF-like modules. Expression and characterization of the EGF-like modules of human Notch-1 implicated in receptor-ligand interactions.

The Ca(2+)-binding epidermal growth factor (cbEGF)-like module is a structural component of numerous diverse proteins and occurs almost exclusively within repeated motifs. Notch-1, a fundamental receptor for cell fate decisions, contains 36 extracellular EGF modules in tandem, of which 21 are potentially Ca(2+)-binding. We report the Ca(2+)-binding properties of EGF11-12 and EGF10-13 from human Notch-1 (hNEGF11-12 and hNEGF10-13), modules previously shown to support Ca(2+)-dependent interactions with the ligands Delta and Serrate. Ca2+ titrations in the presence of chromophoric chelators, 5,5'-Br2BAPTA and 5-NBAPTA, gave two binding constants for hNEGF11-12, Kd1 = 3.4 x 10(-5) M and Kd2 > 2.5 x 10(-4) M. The high-affinity site was found to be localized to hNEGF12. Titration of hNEGF10-13 gave three binding constants, Kd1 = 3.1 x 10(-6) M, Kd2 = 1.6 x 10(-4) M, and Kd3 > 2.5 x 10(-4) M, demonstrating that assembly of EGF modules in tandem can increase Ca2+ affinity. The highest affinity sites in hNEGF11-12 and hNEGF10-13 had 10 to 100-fold higher affinity than reported for EGF32-33 and EGF25-31, respectively, from fibrillin-1, a connective tissue protein with 43 cbEGF modules. A model of hNEGF11-12 based on fibrillin-1 EGF32-33 demonstrates electronegative potential that could contribute to the higher affinity of the Ca(2+)-binding site in hNEGF12. These data demonstrate that the Ca2+ affinity of cbEGF repeats can be highly variable among different classes of cbEGF containing proteins.

Blotting, Western↗

PubMed1997

Serine protease inhibitors in patients with chronic viral hepatitis.

BACKGROUND/AIMS: This study aimed to determine whether deficiency of the major serine protease inhibitors (alpha1-antitrypsin (AAT) or alpha1-antichymotrypsin (ACT)) is associated with increased risk for chronic hepatitis B or C virus (HBV or HCV) infection. METHODS: We studied 709 adults with chronic liver disease who had undergone liver biopsy during the 14-year period 1978-92. Anti-HCV testing was carried out with second-generation ELISA and immunoblot assays (RIBA 2). HBV markers were tested with commercially available radioimmunoassays. ACT and AAT concentrations in plasma were measured with electroimmunoassay and immune nephelometry. Plasma samples were screened for the AAT PiZ deficiency with ELISA technique and phenotyped by isoelectric focusing. The 229Pro-->Ala mutation for ACT deficiency was identified by PCR techniques. RESULTS: Of the 709 patients, 132 (18.6%) were positive for anti-HCV according to RIBA 2. PiZ AAT deficiency was found in 44 (6.2%) of patients (one PiZZ, 38 PiMZ, and PiSZ), while subnormal ACT levels were found in 33 (4.6%) patients, frequencies that were higher than expected in the general population (p=0.0375 and p<0.0001, respectively). Of the PiZ-carriers, 8/44 (18%) were found to be anti-HCV positive according to RIBA 2, as compared to 123/662 (19%) non-PiZ-carriers (p>0.05). One of these patients had cirrhosis, four chronic active hepatitis, and three chronic persistent hepatitis. In contrast, 17/33 (51.5%) of the patients with subnormal ACT were anti-HCV positive (OR=5.2, CI=2.6-10.6; p<0.0001). No relationship was found between HBV infection and AAT deficiency or subnormal ACT levels. Only one patient with subnormal ACT levels was heterozygous for the 229Pro-->Ala mutation of ACT deficiency. There was no significant difference in the histological findings when the patients with subnormal ACT levels or PiZ allele were subgrouped according to HCV status. CONCLUSIONS: There is no overrepresentation of chronic HBV or HCV in heterozygous AAT deficiency, although an association with more severe liver disease in such patients cannot be excluded. In contrast, low plasma levels of ACT that may be acquired or hereditary, due to mutations other than 229Pro-->Ala, are frequent in HCV infection.

Adolescent↗