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Biomedical subjects

D L Phillips

Publications and source records attributed to D L Phillips.

At least 55 records · Page 3Linked to original sources

Reciprocating orthoses for children with myelomeningocele. A comparison of two types.

Since 1987, 22 children with myelomeningocele have been fitted with reciprocating orthoses. The level of the spinal lesions ranged from T10 to L4 and 13 had associated spinal deformities. Twelve of the patients currently use a Reciprocating Gait Orthosis, seven use a Hip Guidance Orthosis or Parawalker, one has progressed to a Knee Ankle Foot Orthosis, one has died and one has been lost to follow-up. The reciprocating orthoses are worn for a mean of 3.5 hours per day (1 to 6.5); daily usage by girls is almost twice that by boys. The mean daily usage by community walkers is 4.2 hours (13 children) as against 2.8 hours by household ambulators (8 children). Active hip flexion is not essential and fixed-flexion contractures up to 35 degrees can be accommodated. The average breakdown rate is 0.45 per year with an average of 1.5 adjustments each year. The average annual cost of a reciprocating orthosis is Aus$750 (375 pounds, US$570); this includes fabrication, adjustments and repairs.

Adolescent↗

Determination of polychlorinated biphenyl levels in the serum of residents and in the homogenates of seafood from the New Bedford, Massachusetts, area: a comparison of exposure sources through pattern recognition techniques.

We measured the residues of polychlorinated biphenyls (PCBs) in the serum of 23 residents of the New Bedford, Massachusetts, area and from two homogenates each of bluefish and lobsters from the same area. We used congener-specific and total Aroclor quantitative approaches, both of which involved gas chromatography with electron capture detection. Using gas chromatography mass spectrometry (electron ionization mode), we confirmed the presence of PCBs in the combined serum samples and in the aliquots of bluefish and lobsters. In measuring the PCB levels in serum, we found good agreement between the two electron capture detector approaches (r > or = 0.97) when the serum of specific congeners was compared to total Aroclor. We used univariate and multivariate quality control approaches to monitor these analyses. Analytical results for bluefish showed a better agreement between the two techniques than did those for lobsters; however, the small number of samples precluded any statistical comparison. We also measured levels of chlorinated pesticides in the serum samples of two groups of New Bedford residents, those with low PCB levels (< 15 ng/ml) and those with high PCB levels (> or = 15 ng/ml). We found that residents with high PCB levels also tended to have higher levels of hexachlorobenzene (HCB) and 1,1-dichloro-2,2-di-(p-chlorophenyl) ethylene (p,p'-DDE). The higher concentration of all three analytes appears to be influenced by employment in the capacitor industry, by seafood consumption, or both. Using Jaccard measures of similarity and principal component analysis we compared the gas chromatographic patterns of PCBs found in the serum of New Bedford area residents with high serum PCBs with the patterns found in homogenates of lobsters (inclusive of all edible portions except the roe), in homogenates of bluefish fillets taken from local waters, and in serum from goats fed selected technical Aroclors (e.g. Aroclors 1016, 1242, 1254, or 1260). The patterns found in human serum samples were similar to the patterns found in lobster homogenates. Both of these patterns closely resembled patterns found in the serum samples of the goat fed aroclor 1254, as demonstrated by both pattern recognition techniques. In addition, the chromatographic patterns of human serum and of lobsters and bluefish homogenates all indicated the presence of PCBs more characteristic of Aroclors 1016 or 1242.

Analysis of Variance↗

Incidence of sensorineural hearing loss in patients evaluated for tympanostomy tubes.

There are currently no standard guidelines for assessing hearing in pediatric patients who are evaluated for tympanostomy tubes. We describe the results of audiologic testing on 600 consecutive pediatric patients evaluated for tube placement. Six patients (1%) were found to have previously undiagnosed unilateral or bilateral moderate or severe neurosensory loss. Patients undergoing evaluation for tympanostomy tube placement have a low but significant likelihood of neurosensory hearing loss and should have age-appropriate hearing assessment as part of their overall evaluation.

Audiometry↗

Results of endoscopic sinus surgery in pediatric patients with chronic sinusitis and asthma.

OBJECTIVE: To determine the efficacy of endoscopic sinus surgery in pediatric patients with chronic sinusitis and asthma. SETTING: Patients were selected from the tertiary care practice of a pediatric pulmonologist (R.S.) and immunologist (R.L.W.); all underwent sinus surgery at Children's Medical Center at Dallas (Tex). PATIENTS: Fourteen pediatric patients aged 3.5 to 13 years with severe asthma requiring at least intermittent systemic steroid therapy. All patients had a history of sinusitis aggravating asthma and all had computed tomographic evidence of chronic sinus disease. INTERVENTION: All patients underwent endoscopic sinus surgery consisting of bilateral total ethmoidectomies and middle meatus antrostomies at a minimum. MAIN OUTCOME MEASURES: The period 12 months prior to surgery was compared with 12 months postoperatively with regard to total hospitalization days for asthma treatment, number of school days missed, pulmonary function test results, and systemic glucocorticoid medication requirements. Symptom scores for asthma and sinusitis were assessed via parental questionnaire both preoperatively and postoperatively. RESULTS: No significant difference was found for pulmonary function test results. Eleven of 14 patients demonstrated a significant reduction in hospitalization and school days missed. Twelve of 14 patients experienced a reduction in glucocorticoid requirements. Eleven of 14 and 13 of 14 patients experienced a significant improvement in asthma and sinusitis symptom scores. CONCLUSION: Endoscopic sinus surgery was effective in reducing sinusitis and improving the overall management of asthma in a majority of study patients.

Absenteeism↗

Ethnic differences in the recurrence of adenomatous polyps after colonoscopic polypectomy.

A retrospective study was done of polyp recurrence rates following an initial clearing colonoscopy for adenomatous polyps. The intent of the study was to identify risk factors that would predict a greater risk for recurrence in Hawaii's ethnically diverse population. When the initial exam detected multiple polyps, a higher recurrence rate was found in Caucasian patients.

Adenomatous Polyps↗

Ontogenesis of intestine morphology and intestinal disaccharidases in chickens (Gallus gallus) fed contrasting purified diets.

Two groups of growing posthatching Cornish x Rock cross chickens were fed with either a carbohydrate-containing (52.5%) or a carbohydrate-free diet. At 36 days after hatching some of the chicks in each group were shifted to the opposite diet. Chickens fed on a carbohydrate-containing diet grew faster and achieved higher asymptotic masses than chickens fed on a carbohydrate-free diet. Chickens fed on a carbohydrate-free diet had longer intestines and larger intestinal areas than chickens of the same mass fed on a carbohydrate-containing diet. In both groups sucrase and maltase activity (standardized by either intestinal area or mass) increased from day 1 to approximately day 17. After day 17, chickens fed on a carbohydrate-containing diet exhibited 1.8 and 1.9 times higher sucrase and maltase activities per unit intestinal area, respectively, than chickens fed on a carbohydrate-free diet. Analysis of covariance was used to estimate the contribution of sucrase and the sucrase-independent maltases to maltase activity, and to estimate the effect of diet on the sucrase-independent maltases. Sucrase contributed 80% and 75% of the maltase activity in carbohydrate and carbohydrate-free fed chickens, respectively. Chickens shifted from a carbohydrate-free to a carbohydrate diet converged in gross intestinal morphology and intestinal sucrase and maltase levels with carbohydrate-fed chickens within 8 days. Chickens shifted from carbohydrate to carbohydrate-free diets, in contrast, did not show appreciable changes in intestinal length and after 8 days had not reduced levels of sucrase and maltase to those of chickens fed on the carbohydrate-free diet. A comparison of integrated maltase intestinal activity with published data on glucose uptake showed that the ratio of maltose hydrolysis to glucose uptake seemed to be about 7 and to remain relatively invariant during ontogeny. Because so little is known about the interaction between hydrolysis and uptake in vivo, it is difficult to determine if this relatively high ratio represents excess hydrolytic capacity or if it is needed to provide high lumenal glucose concentrations that maximize uptake.

Animals↗

Evidence for a separate food-entrainable circadian oscillator in the pigeon.

In Experiment 1, four pigeons lived in a metabolic chamber on a 12h:12h LD cycle where they maintained a reduced body weight by consuming a daily ration of food presented at the eighth hour of the photophase. Body temperature (Tb) and oxygen consumption (Vo2) increased prior to the daily feeding. The possibility that a food-entrainable oscillator timed these anticipatory responses was tested by four manipulations, conducted in successive phases, each of which involved eliminating the regularly scheduled food presentation, which is the putative entraining stimulus for such an oscillator, while the 12h:12h LD cycle remained in effect. The manipulations, and their outcomes, were: when fasting was imposed for 3 days, the anticipatory responses continued to occur; when ad lib feeding was allowed for 11 days, the anticipatory responses were mostly eliminated; when fasting was reimposed for 5 days, there was evidence that the anticipatory responses reoccurred; and, when the time of the daily feeding was phase-shifted earlier in the photophase for 8 days, anticipatory responses persisted at the original feeding time and simultaneously developed at the new feeding time. In the first phase of Experiment 2, key pecking by two pigeons produced food only during hours 9-11 of the daily photophase (12h:12h LD). In this condition, Tb increased and key pecking occurred in anticipation of the daily period of food availability. Evidence for a food-entrained oscillator was sought in a second phase when constant dim light (LL) was imposed without changing the hours of food availability.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Analysis of microsurgical penile revascularization results by etiology of impotence.

We reviewed the results of microsurgical penile revascularization, with or without a combined procedure to correct cavernosal venous leakage, in 50 consecutive patients with vasculogenic impotence. All patients underwent an extensive preoperative evaluation, including dynamic infusion cavernosography and cavernosometry, and selective penile arteriography. Overall 48% (24 patients) had an excellent postoperative result, 40% (20 patients) were improved and 12% (6 patients) failed, with a median followup of 24 months (range 19 to 56). Furthermore, these results appear durable with no significant difference in length of followup between groups irrespective of surgical outcome (p > 0.05). Analysis of surgical outcomes by preoperative etiology of impotence (pure arterial versus arterial combined with corporeal venous dysfunction) revealed a statistically significant advantage of an excellent surgical outcome in patients with pure arterial impotence compared to those with mixed etiology with results of 67% and 42%, respectively (p < 0.01). There was no significant difference in outcome when patients were analyzed with respect to age or duration of impotence (p > 0.05). We conclude that in patients with arteriogenic impotence identification of concomitant corporeal veno-occlusive dysfunction diagnosed by preoperative dynamic infusion cavernosography and cavernosometry may be helpful, not only in planning a more physiological surgical procedure but also in predicting long-term postoperative success.

Adult↗

Association of virulent and avirulent strains of bluetongue virus serotype 11 with premature births of late-term bovine fetuses.

Two strains of bluetongue virus serotype 11 (BTV 11), UC-2 avirulent and UC-8 neurovirulent in newborn mice, were inoculated into late-term bovine fetuses to investigate whether infection with these two BTV strains in late gestation would produce congenital infection and pathological changes. Fetuses were inoculated by intramuscular injection through the uterine wall at 243 days gestation and recovered after spontaneous delivery. In calves inoculated with UC-8, births occurred 15 to 27 days before expected parturition, resulting in small, weak calves. These calves had a mild encephalitis and were unthrifty at birth. Calves inoculated with UC-2 appeared healthy when born 7 to 11 days prior to expected parturition. No lesions were found in these calves at necropsy. All calves seroconverted by the time of birth. Viraemia was present in the calves inoculated with UC-8 and in one calf inoculated with UC-2. Plasma cortisol concentrations were prematurely elevated, particularly in the calves inoculated with UC-8, indicating that they were stressed by the infection. The elevated cortisol, associated with an active congenital infection caused by bluetongue virus serotype 11 strain UC-8, is capable of causing premature delivery of low birth-weight, weak calves.

Animals↗

Infection of bovine fetuses at 120 days' gestation with virulent and avirulent strains of bluetongue virus serotype 11.

Bluetongue virus infection in sheep and cattle during fetal development causes neuropathology. Two strains of bluetongue virus serotype 11 designated as UC-2 and UC-8 have different virulence patterns in newborn mice. These viruses have distinctly different electropherotype patterns on polyacrylamide gel electrophoresis indicating a genetic difference in these two viruses of the same serotype. Four bovine fetuses each were inoculated intramuscularly with either UC-2 or UC-8, and one fetus was inoculated with placebo. The inoculation was made intramuscularly through the uterine wall at 120 days' gestation, and the bovine fetuses were recovered by cesarean section 12 or 20 days after inoculation. Fetal blood was collected for virus isolation and serology. Virus was reisolated from brain, blood, lung and liver. Both strains, UC-2 and UC-8, cause severe lesions in the 120 day fetuses. The encephalomalacic lesions occurred earlier and were more severe in fetuses inoculated with UC-8 as compared to those inoculated with UC-2. The subtle differences observed in the fetuses inoculated with the two different strains suggest that there is a difference in pathogenic potential of the two viruses. These differences do not appear to be completely dependent upon the host species.

Animals↗

Interlaboratory study of cellular fluorescence intensity measurements with fluorescein-labeled microbead standards.

To determine the precision of cellular fluorescence intensity (FI) measurements derived from labeled microbead standards, FI results were compared from 43 different flow cytometers in 34 laboratories. All laboratories analyzed prepared aliquots of fluoresceinated calf thymocyte nuclei (Fluorotrol), human lymphocytes stained with fluoresceinated anti-CD4 antibody, and fluoresceinated microbeads used as both internal and external standards. Measurements were conducted by most laboratories on the third and fourth days after sample preparation. Results for percent of events within the gates and the histograms returned by participants indicated that the samples had remained stable and that gated populations had been properly identified. All standard curves showed strong linearity, and the pooled results from all standards produced a best-fit curve that was in close agreement with the assigned values. Nonetheless, results for cellular FI were highly variable, with CVs of 20-34%. Agreement within lab/instrument was much better, with CVs ranging from 3.0 to 9.9%. The overall variability was not obviously attributable to differences in the types of cytometer, nor could it be explained by attributes of the standard curves or any other single variable examined. However, the application of a corrective factor based on FI results for Fluorotrol allowed a two-fold improvement in the precision of FI measurements on CD4-stained lymphocytes, with an overall CV of 11%. Uncharacterized differences in the operating conditions of flow cytometers can influence cellular FI measurements, but consistent results can be obtained if a stained cellular calibrator is analyzed in addition to the proper microbead standards.

CD4-Positive T-Lymphocytes↗

Human exposure to polychlorinated biphenyls in Greater New Bedford, Massachusetts: a prevalence study.

A study was conducted in the community of Greater New Bedford, Massachusetts, from 1984 through 1987 to assess the prevalence of elevated levels of polychlorinated biphenyls (PCBs) in the serum of individuals aged 18 to 64 years who had resided in the area for at least 5 years. Eight hundred and forty subjects were interviewed, examined, and tested in a cross-sectional sample of the towns of Acushnet, Dartmouth, and Fairhaven and the city of New Bedford. Serum PCBs were measured to estimate the extent of human exposure. Because of documented environmental contamination by PCBs in the New Bedford area, and the practice of recreational fishing in the harbor for food, a significant number of persons with elevated serum PCB levels were expected to be identified. Instead, the prevalence of elevated serum PCBs in the sample was found to be typical of "unexposed" urban populations in the United States. Only 1.3% of the subjects had serum PCB levels greater than 30 ppb. The same percentage was observed among males (n = 391) and females (n = 449). The geometric means of PCB levels were 4.3 ppb among males (Range = 0.50-60.9) and 4.2 ppb among females (Range = 0.38-154). We conclude that the prevalence of elevated serum PCBs is low in the population of Greater New Bedford.

Adolescent↗

A study of cytokine production in acute graft-vs-host disease.

The role of cytokines in the development of acute graft-vs-host disease (GVHD) was investigated in B6AF1 mice that were injected with parental A/J lymphocytes. Splenocytes from GVH mice exhibited an increased capacity to produce interleukin (IL)-1, IL-6, and TNF-a when stimulated in culture with lipopolysaccharide (LPS). This enhanced capacity was diminished following in vivo treatment with immunosuppressive drugs. Concanavalin A-stimulated GVH spleen cells produced significantly lower levels of IL-2 but higher levels of interferon-gamma (IFN-gamma) than did syngeneic spleen cells. Immunosuppressive therapy in vivo increased the capacity of GVH spleen cells to produce IL-2. However, immunosuppressants differed in their effects on IFN-gamma production. Sch 24937 (6-bromo-5-chloro-2-[1-(methylsulfonyl)acetyl] 3-(2-pyridyl)indole) enhanced or had no effect while cyclosporin A consistently decreased the capacity of splenocytes to produce this lymphokine. These results indicate that the capacity of GVH splenocytes for cytokine production can be differentially affected by the actions of some pharmacological agents. The data also indicate that there may be differential regulation of the production of IL-2 and IFN-gamma by the Th1 subset in the GVH spleen.

Acute Disease↗

Energetic responses of pigeons during food deprivation and restricted feeding.

Pigeons ate food ad lib, then fasted for several days, and finally ate a controlled amount of food once a day for several months to maintain body weight at 80% of the ad lib value. Whole-body dry heat loss (HL) and core body temperature (Tb) were measured continuously for each pigeon. Thermal conductance (C) was calculated from HL and Tb. Relative to ad lib feeding, 24-h HL was reduced by approximately 50% during fasting and controlled feeding. The majority of energy savings was achieved by lowering C, which appeared to maintain a saturated low value throughout most of the light and dark phases. Therefore, the pigeon's characteristic high Tb in the daily light phase during fasting and food restriction does not necessarily imply high energy expenditure. In the dark phase, the fasting pigeon's characteristically low Tb enhances energy savings already being achieved through lowered C. The daily cycle in Tb, and to a lesser extent in HL and C, was strongly altered by occasional probe variations in the amount of food given at the single daily feeding and by a shift in the time of the daily feeding.

Animals↗

What to do with the patient with a positive HCV antibody test.

A test to measure hepatitis C antibody has recently been developed. The development of the antibody test was closely followed by the publication of two trials which demonstrated the efficacy of interferon alfa in the treatment of transfusion-associated hepatitis C. The author discusses management of the patient with a positive hepatitis C virus (HCV) antibody test, including an approach to sorting out those patients who have false positive tests, information about modes of transmission for those patients who are asymptomatic carriers, and guidelines to determine which patients may be candidates for interferon therapy.

Hepacivirus↗

Model system evaluating fluorescein-labeled microbeads as internal standards to calibrate fluorescence intensity on flow cytometers.

Fluorescence intensity calibration was evaluated in a model system for flow cytometers using commercially available fluorescein-labeled microbeads as internal standards and stabilized fluoresceinated thymus cell nuclei (Fluorotrol) as surrogates for stained mononuclear cells. Spectrophotometrically determined calibration values for the microbeads were used to generate a standard curve that converted green fluorescence histogram channels into molecular equivalents of soluble fluorescein (MESF). In 19 analyses repeated during a single run, the coefficients of variation (CVs) for the derived MESF values on both dimly and brightly stained Fluorotrol populations were less than 2%. In 26 separate determinations over 14 weeks, the CVs of the derived MESF values were less than 3%. The MESF values of the dim and bright Fluorotrol populations derived from the microbead standard curves were both about 50% lower than those determined by direct spectrophotometric analysis of Fluorotrol. The analytical imprecision of fluorescence intensity measurements in this idealized model system has a CV less than 3%, and the analytical inaccuracy shows that calibration in MESF units remains uncertain over about a two-fold range.

Animals↗

Colonic lymphoma in the transplant patient.

A 64-year-old male renal transplant recipient developed rectal bleeding caused by a primary lymphoma of the colon, an unusual site for initial disease involvement. Renal transplant recipients may be at increased risk for the development of primary colonic lymphoma, a diagnosis that should be considered in transplant patients who develop abdominal pain, rectal bleeding, or intestinal perforation. The unique clinical features and special management considerations of colonic lymphoma in the renal transplant recipient are discussed.

Colon↗