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Biomedical subjects

M Dillon

Publications and source records attributed to M Dillon.

At least 19 recordsLinked to original sources
PubMed2002

Focally enhanced gastritis in children with Crohn's disease and ulcerative colitis.

OBJECTIVES: Focally enhanced gastritis (FEG) has been suggested as a specific diagnostic marker for patients with Crohn's disease. However, the utility of FEG for distinguishing Crohn's disease from ulcerative colitis is uncertain in adults, and the occurrence of this lesion in children has not been defined. The aim of this study was to evaluate the occurrence of FEG and other gastric histological abnormalities in children with inflammatory bowel disease (IBD) and to examine the utility of FEG in discriminating between ulcerative colitis and Crohn's disease. METHODS: This is a retrospective, case-controlled study of upper GI histopathological findings in children with IBD. Gastric histopathology was defined and graded according to the Updated Sydney System. RESULTS: FEG was present in 28 of 43 (65.1%) children with Crohn's disease and five of 24 (20.8%) children with ulcerative colitis, compared to three of 132 (2.3%) children without IBD or one of 39 (2.6%) children with Helicobacter pylori infection. There were no differences between those with and without FEG with regard to upper GI symptoms or previous anti-inflammatory drug ingestion (5-aminosalicylic acid compounds or steroids). All patients with H. pylori infection had chronic antral gastritis, but only one child with H. pylori had FEG. In addition, mild to moderate chronic gastritis was present in 15 of 43 (34.9%) children with Crohn's disease and in 12 of 24 (50%) patients with ulcerative colitis. CONCLUSIONS: The presence of FEG suggests underlying IBD. Although FEG is particularly common in children with Crohn's disease, it does not reliably differentiate between Crohn's disease and ulcerative colitis.

Case-Control Studies↗
PubMed2001

Mountaineering in thin air. Patterns of death and of weather at high altitude.

An 8000-m peak bring challenges of extremes of hypoxia and weather as well as the normal hazards of climbing itself. These challenges have taken a severe toll: 604 mountaineers have died on those great peaks since 1950. Little is known about whether mountain height, use of supplemental oxygen, or team size might influence rates of death or of success. However, such information may provide insights not only to our understanding of the limits of human performance, but also to mountaineers in making decisions on these peaks. We present several examples from a research program that is attempting to analyze factors that potentially influence success or death rates on the 8K peaks. (1) Apparent risk of death in the notorious Khumbu Icefall on Mt. Everest has declined dramatically in recent years. This decline could reflect improved route finding and technique, but might also reflect climate warming, which has caused the Khumbu glacier to shrink and slow in recent decades. (2) Risk of death during descent from an 8000-m peak increases with the height of the peak. (3) Risk of death during descent from the summit of Everest or of K2 is elevated for climbers not using supplemental oxygen. (4) We outline some new studies that are exploring how convective heat loss, which influences wind chill, changes with altitude as well as the incidence of storms: both factors will impact the probability success and death of Himalayan mountaineers.

Altitude↗
PubMed1999

A comparison of the calcium-free phosphate binder sevelamer hydrochloride with calcium acetate in the treatment of hyperphosphatemia in hemodialysis patients.

Current phosphate binders used in hemodialysis patients include calcium-based binders that result in frequent hypercalcemia and aluminum-based binders that result in total body aluminum accumulation over time. This investigation describes the use of a calcium- and aluminum-free phosphate-binding polymer in hemodialysis patients and compares it with a standard calcium-based phosphate binder. An open-label, randomized, crossover study was performed to evaluate the safety and effectiveness of sevelamer hydrochloride in controlling hyperphosphatemia in hemodialysis patients. After a 2-week phosphate binder washout period, stable hemodialysis patients were administered either sevelamer or calcium acetate, and the dosages were titrated upward to achieve improved phosphate control over an 8-week period. After a 2-week washout period, patients crossed over to the alternate agent for 8 weeks. Eighty-four patients from eight centers participated in the study. There was a similar decrease in serum phosphate values over the course of the study with both sevelamer (-2.0 +/- 2.3 mg/dL) and calcium acetate (-2.1 +/- 1.9 mg/dL). Twenty-two percent of patients developed a serum calcium greater than 11.0 mg/dL while receiving calcium acetate, versus 5% of patients receiving sevelamer (P < 0.01). The incidence of hypercalcemia for sevelamer was not different from the incidence of hypercalcemia during the washout period. Patients treated with sevelamer also sustained a 24% mean decrease in serum low-density lipoprotein cholesterol levels. Sevelamer was effective in controlling hyperphosphatemia without resulting in an increase in the incidence of hypercalcemia seen with calcium acetate. This agent appears quite effective in the treatment of hyperphosphatemia in hemodialysis patients, and its usage may be advantageous in the treatment of dialysis patients.

Acetic Acid↗
PubMed1999

Decreased CD8 cell-mediated viral suppression and other immunologic characteristics of women who transmit human immunodeficiency virus to their infants.

CD8 T cell function, lymphocyte surface phenotype, serum markers of immunologic activation, and viral burden were assessed in 75 human immunodeficiency virus (HIV)-infected pregnant women, including 9 who transmitted infection to their infants. Serial studies during and after pregnancy showed no significant differences in levels of cell-surface or serum activation molecules in transmitting compared to nontransmitting mothers, with the exception of a postpartum increase in tumor necrosis factor alpha in transmitting women. The transmitting women had a median plasma viral load of 65,516 RNA copies/mL at delivery versus 5139 in nontransmitting women. During the third trimester, the CD8 cells of 81% of the nontransmitting and 44% of the transmitting mothers suppressed HIV production in vitro by >50%. Women with <50% suppression had a 3.4 times greater risk of transmitting HIV to their infants. CD8 suppression and viral load were interrelated, but when either CD4 percent or AZT use was controlled for, suppression was still significant.

CD3 Complex↗
PubMed1999

A randomized trial of sevelamer hydrochloride (RenaGel) with and without supplemental calcium. Strategies for the control of hyperphosphatemia and hyperparathyroidism in hemodialysis patients.

OBJECTIVE: We have previously shown sevelamer hydrochloride (RenaGel) to be an effective and well-tolerated treatment for hyperphosphatemia in hemodialysis patients. PATIENTS AND METHODS: We performed a randomized clinical trial to compare the efficacy of RenaGel alone and RenaGel with calcium, using the serum phosphorus concentration and intact parathyroid hormone (PTH) as the principal outcomes of interest. Calcium (900 mg elemental) was provided as a once-nightly dose on an empty stomach. 71 patients were randomized and included in the intent-to-treat population; 55 completed the 16-week study period (2 weeks washout, 12 weeks treatment, 2 weeks washout). 49% of subjects were taking vitamin D metabolites. RESULTS: Serum phosphorus and PTH rose significantly when patients stopped their phosphate binders during both washout periods. RenaGel and RenaGel with calcium were equally effective at reducing serum phosphorus (mean change -2.4 mg/dL vs. -2.3 mg/dL). RenaGel with calcium was associated with a small increase in serum calcium (mean change 0.3 mg/dL vs. 0.0 mg/dL in RenaGel group, P = 0.09) that was not statistically significant. During the treatment phase, the reduction in PTH tended to be greater in the RenaGel with calcium group (median change -67.0 vs. -22.5 pg/mL in RenaGel group, P = 0.07). Non-users of vitamin D metabolites treated with RenaGel with calcium experienced a significant decrease in PTH (median change -114.5 vs. -22 pg/mL in RenaGel group, P = 0.006). Adverse events were seen with equal frequency in both groups, being generally mild in intensity, and rarely attributable to the drugs. CONCLUSION: We conclude that RenaGel and RenaGel with calcium are similarly effective in the treatment of ESRD-related hyperphosphatemia. Provision of supplemental calcium or metabolites of vitamin D with RenaGel may enhance control of hyperparathyroidism.

Calcium↗
PubMed1998

A search for the optimal stimulus.

How do stimulus size and item number relate to the magnitude and direction of error on center estimation and line cancellation tests? How might this relationship inform theories concerning spatial neglect? These questions were addressed by testing twenty patients with right hemisphere lesions, eleven with left hemisphere lesions and eleven normal control subjects on multiple versions of center estimation and line cancellation tests. Patients who made large errors on these tests also demonstrated an optimal or pivotal stimulus value, i.e., a particular size center estimation test or number of lines on cancellation that either minimized error magnitude relative to other size stimuli (optimal) or marked the boundary between normal and abnormal performance (pivotal). Patients with right hemisphere lesions made increasingly greater errors on the center estimation test as stimuli were both larger and smaller than the optimal value, whereas those with left hemisphere lesions made greater errors as stimuli were smaller than a pivotal value. In normal subjects, the direction of errors on center estimation stimuli shifted from the right of true center to the left as stimuli decreased in size (i.e., the crossover effect). Right hemisphere lesions exaggerated this effect, whereas left hemisphere lesions diminished and possibly reversed the direction of crossover. Error direction did not change as a function of stimulus value on cancellation tests. The demonstration of optimal and pivotal stimulus values indicates that performances on center estimation and cancellation tests in neglect are only relative to the stimuli used. In light of other studies, our findings indicate that patients with spatial neglect grossly overestimate the size of small stimuli and underestimate the size of large stimuli, that crossover represents an "apparent" shift in error direction that actually results from normally occurring errors in size perception, and that the left hemisphere is specialized for one aspect of size estimation, whereas the right performs dual roles.

Aged↗
PubMed1998

The microlaparoscope should be used routinely for diagnostic laparoscopy.

OBJECTIVE: To describe the experience of changing from the use of the 10-mm standard laparoscope to the use of the 2-mm microlaparoscope (MicroLap, Imagyn Medical Inc., Laguna Niguel, CA) and to compare the amount of postoperative pain and requirement for analgesics after each technique. DESIGN: Prospective study. SETTING: Day surgery unit in an academic reproductive medicine unit. PATIENT(S): One hundred thirty-five women undergoing diagnostic microlaparoscopy. INTERVENTION(S): Diagnostic laparoscopy with a 2-mm instrument. Recording of postoperative pain on an analog scale. MAIN OUTCOME MEASURE(S): Ability to complete the procedure satisfactorily with the microlaparoscope, pain scores, and use of analgesics. RESULT(S): All diagnostic procedures were performed satisfactorily with the use of the MicroLap. Patients who underwent MicroLap procedures had significantly less abdominal pain postoperatively, but there was no difference in shoulder tip (gas-related) pain. Less analgesia was required after the microlaparoscopy. CONCLUSION(S): In most situations, the microlaparoscope is the instrument of choice for initial diagnostic laparoscopy. The 10-mm laparoscope should be used only as a secondary instrument after microlaparoscopy, if indicated.

Abdominal Pain↗
PubMed1998

Early prognostic indicators in primary perinatal human immunodeficiency virus type 1 infection: importance of viral RNA and the timing of transmission on long-term outcome.

The time of perinatal human immunodeficiency virus type 1 (HIV-1) transmission and the pattern of early plasma viremia as predictors of disease progression were evaluated in infected infants followed from birth. Cox proportional hazards modeling demonstrated that a 1-log higher HIV-1 RNA copy number at birth was associated with a 40% increase in the relative hazard (RH) of developing CDC class A or B symptoms (P = .004), a 60% increase in developing AIDS (P = .01), and an 80% increase in the of risk death (P = .023) over the follow-up period of up to 8 years. The peak HIV-1 RNA copy number for infants during primary viremia was also predictive of progression to AIDS (RH, 9.9; 95% confidence interval [95% CI], 1.8-54.1; P = .008) and death (RH, 6.9; 95% CI, 1.1-43.8; P = .04). The results indicate that high levels of HIV-1 RNA at birth and during primary viremia are associated with early onset of symptoms and rapid disease progression to AIDS and death in perinatally infected children.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Optimization of specimen-handling procedures for accurate quantitation of levels of human immunodeficiency virus RNA in plasma by reverse transcriptase PCR.

Human immunodeficiency virus type 1 (HIV-1) RNA levels in plasma are currently widely used clinically for prognostication and in monitoring antiretroviral therapy. Accurate and reproducible results are critical for patient management. To determine the effects of specimen collection and handling procedures on quantitative measurement of HIV-1 RNA, we compared anticoagulants and sample processing times. Whole blood was collected from 20 HIV-1-infected patients in EDTA, acid citrate dextrose (ACD), and heparin tubes, aliquoted, and stored at room temperature. Plasma was separated from whole-blood aliquots prepared at < or =1, 3, 6, 24, and 48 h postcollection and then stored at -70 degrees C until use. HIV-1 RNA levels were determined by the AMPLICOR HIV-1 MONITOR assay. Heparinized plasma samples, which were pretreated with heparinase prior to analysis, had the lowest baseline HIV-1 RNA levels. In the first 6 h, HIV-1 RNA levels decreased by 10, 20, and 31% in EDTA, ACD, and heparin tubes, respectively. From 6 to 48 h postcollection, HIV-1 RNA levels decreased in all anticoagulants, albeit at a slower, more consistent rate. Our results indicate that EDTA should be the anticoagulant of choice for plasma HIV-1 RNA measurement by reverse transcriptase PCR, but ACD tubes are acceptable if the plasma is separated within 6 h of blood collection. Caution must be applied in the interpretation of absolute HIV-1 RNA copy number values obtained with suboptimal specimen collection and processing procedures.

Adolescent↗
PubMed1998

Colonoscopy under general anesthesia in children.

OBJECTIVE: In children, colonoscopy is usually performed using deep sedation that may be associated with significant risks. The purpose of this study was to evaluate the safety of colonoscopy performed under general anesthesia. METHODS: All patients undergoing colonoscopy during a 3-year period were reviewed for the study. One hundred and thirty-six procedures were performed. Colonoscopies were performed by a pediatric gastroenterologist. Anesthesia was administered by a pediatric anesthetist in a gastroenterology procedure room, adjacent to the operating recovery area. RESULTS: Three patients had significant abdominal pain and tenderness after the procedure, 1 of whom suffered a perforation of the sigmoid colon. This patient had severe ulcerative colitis. The gastrointestinal complication rate was no higher than reported in adult patients undergoing colonoscopy under sedation. No significant complications relating to the administration of anesthesia were encountered. CONCLUSION: We conclude that colonoscopy performed under general anesthesia in children is a very safe procedure. It is superior to the use of sedation because the child is not placed at risk of respiratory compromise. Furthermore, the procedure is less worrisome for children when performed under a general anesthetic.

Abdominal Pain↗
PubMed1997

Immunologic activation during pregnancy: serial measurement of lymphocyte phenotype and serum activation molecules in HIV-infected and uninfected women.

Immunologic alterations occur during pregnancy, but the effect of pregnancy on HIV infection is controversial. We characterized some of the immunologic alterations with potential to influence HIV disease in 99 infected and 46 uninfected women during pregnancy and up to 6 months post-partum. Immunophenotyping to quantitate the major lymphocyte subsets and determine expression of activation and adhesion molecules on T cells was performed using 3-color staining and laser flow cytometry. Serum neopterin, beta 2-microglobulin, and tumor necrosis factor-alpha (TNF alpha) were quantitated using commercial immunoassays. HIV + pregnant women were compared to uninfected pregnant subjects and to reference ranges established on healthy, HIV-seronegative non-pregnant female controls. Both CD4 and CD8 T cell subsets were increased in HIV-negative pregnant women compared to non-pregnant controls. In HIV-infected pregnant women, CD4 T cells were low and CD8 cells were elevated compared to HIV-negative pregnant and non-pregnant women. Levels of subsets were stable during pregnancy and postpartum in both groups of women. Evidence of peripheral immune activation was found during the later stages of pregnancy. Increases in HLA-DR and CD38 activation antigens on CD8 cells, serum neopterin and beta-2-microglobulin were seen during pregnancy in HIV-negative women. These correlates of immune activation were increased in HIV-infected pregnant women and increased further during pregnancy, paralleling changes seen in uninfected pregnant women. These immunologic alterations may directly or indirectly enhance viral replication, impacting the long-term course of HIV disease.

Biopterins↗
PubMed1997

Timing of lymphocyte activation in neonates infected with human immunodeficiency virus.

Human immunodeficiency virus (HIV) infection in children is associated with qualitative and quantitative changes in the peripheral lymphocyte surface phenotype beyond the normal maturational changes. Neonates, however, have been reported to have a delayed immune response to HIV compared to HIV-infected adults. We prospectively performed immunophenotyping of T lymphocytes by three-color immunofluorescent labeling and laser flow cytometry to determine the timing of phenotypic alterations in 112 neonates born to HIV-infected mothers. Serial testing was performed at birth (cord blood) and at 2, 6, and 12 weeks of age. Data were divided retrospectively for analysis into those for HIV-infected (n = 14) infants and those for exposed, uninfected infants. Our results show that both infected and uninfected infants had a decline in the percentages and numbers of CD4 cells beginning at 2 weeks of age but that the decline was greater in the HIV-infected group. The activation and differentiation of CD8 T cells in HIV+ infants were shown by a significant increase in CD45RA- CD45RO+ CD8+ cells by 6 weeks of age and by increases in CD8+ S6F1+ CD3+ cells and HLA-DR+ CD38+ CD8+ cells by 2 weeks of age. These results indicate that HIV-infected neonates show alterations in T-cell phenotype reflecting those reported for older HIV-infected children. Most importantly, neonatal T cells are able to respond to HIV within the first weeks of life.

Antigens, CD↗
PubMed1996

Presence of human immunodeficiency virus (HIV) type 1 and HIV-1-specific antibodies in cervicovaginal secretions of infected mothers and in the gastric aspirates of their infants.

The presence of human immunodeficiency virus (HIV) in cervicovaginal secretions (CVS) may be a risk factor for perinatal transmission. CVS of 25 women were evaluated for HIV and HIV mucosal antibodies; 16 infants had gastric aspirates cultured. Maternal plasma HIV was measured by quantitative RNA polymerase chain reaction. Seven women (28%), 4 of 19 pregnant and 3 of 7 nonpregnant, had HIV in CVS. Two of 4 HIV-infected neonates had positive gastric aspirate cultures. The 4 pregnant women with HIV in CVS did not transmit infection. HIV-specific secretory IgA was present in CVS of 10 (42%) of 24 women (in 3 cases concurrent with virus). Plasma HIV RNA levels at delivery were higher among transmitters (mean, 68,921 copies/mL) than nontransmitters (mean, 9457 copies/mL). Intermittent HIV shedding in CVS occurred despite mucosal antibodies and did not necessarily correlate with maternal plasma HIV RNA copy number. The presence of HIV in newborn gastric aspirates may be a risk factor for perinatal infection.

Cervix Uteri↗
PubMed1996

Viscous carbomer eye drops in patients with dry eyes. Efficacy and safety. A randomized, open, cross-over, multicentre study.

The efficacy and safety of a new carbomer containing ocular gel was compared to a commonly used 1.4% polyvinyl alcohol-based (PVA) offificial tear preparation. Sixty-one patients with symptoms and signs of dry eyes were treated with each preparation separately for two weeks in a multicentre, randomized, open cross-over study. A statistically significant difference in favour of the new viscous carbomer eye drops compared to the PVA preparation was achieved in reducing the symptom of 'dryness', the total symptom score and in prolonging the break-up time. During the carbomer eye drops period the mean daily frequency of application was 3.92 compared to 4.64 for the PVA eye drops period (p = 0.02). Twenty-three patients (38%) reported adverse events only while using the carbomer gel and 5 (8%) only while using the PVA eye drops (p < 0.001). 'Blurred vision' was the most common adverse event reported. The present carbomer containing ocular gel may offer advantages in the treatment of dry eyes.

Acrylates↗