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Biomedical subjects

Robert Jones

Publications and source records attributed to Robert Jones.

At least 19 recordsLinked to original sources

Successful stenting for Budd-Chiari syndrome after pediatric liver transplantation: a case series and review of the literature.

Hepatic venous outflow obstruction, known as Budd-Chiari syndrome, is a rare but serious complication of orthotopic liver transplantation and may lead to graft loss. Our aim was to describe a single center experience of percutaneous interventional management of hepatic outflow obstruction post liver transplantation in children. Three children with post-transplant hepatic venous outflow obstruction were treated successfully with percutaneous stent placement. This resulted in long-term resolution of symptoms and was superior to balloon angioplasty both in our series and in cases reported in the literature. Stenting may be the treatment of choice for hepatic venous obstruction after pediatric liver transplantation, particularly if there is a recurrence of stenosis after balloon dilatation.

Budd-Chiari Syndrome↗

Frictional forces between cohesive powder particles studied by AFM.

A range of commercially important powders (hydrated alumina, limestone, titania and zeolite) and glass ballotini were attached to atomic force microscope cantilevers, and inter-particle friction forces studied in air using lateral force microscopy (LFM). The in situ calibration procedure for friction forces is described. LF images, line profiles, LF histograms, surface roughness, pull-off forces, and the load dependence of friction in the range 0-25 nN were studied for both particle-particle and particle-wall (steel) contacts. The single-particle friction results are discussed in terms of contact mechanics theory. Particle-particle contacts showed load-dependent friction, involving single asperity contacts (non-linear behaviour) or multi-asperity contacts (linear behaviour). Particle-wall contacts usually showed little load dependence and were more adhesive. The results are also related to shear stress-normal stress data (yield loci) for the same materials from bulk shear testers.

Friction↗

Adenomatoid tumor of the testes.

Adenomatoid tumors are rare benign neoplasms thought to be of mesothelial origin. Although most reported cases arise from the epididymis, rare cases have been reported in the spermatic cord, testicular tunica, ejaculatory ducts, prostate, and suprarenal recess. In female subjects, adenomatoid tumors are commonly found in the uterus and fallopian tubes. Because of the benign nature of this tumor, the treatment of choice is local excision. We describe a rare case of adenomatoid tumor of the testis treated by local excision.

Adenomatoid Tumor↗

Depression as a risk factor for mortality after coronary artery bypass surgery.

BACKGROUND: Studies that have shown clinical depression to be a risk factor for cardiac events after coronary artery bypass graft (CABG) surgery have had small sample sizes, short follow-up, and have not had adequate power to assess mortality. We sought to assess whether depression is associated with an increased risk of mortality. METHODS: We assessed 817 patients undergoing CABG at Duke University Medical Center between May, 1989, and May, 2001. Patients completed the Center for Epidemiological Studies-Depression (CES-D) scale before surgery, 6 months after CABG, and were followed-up for up to 12 years. FINDINGS: In 817 patients there were 122 deaths (15%) in a mean follow-up of 5.2 years. 310 patients (38%) met the criterion for depression (CES-D > or =16): 213 (26%) for mild depression (CES-D 16-26) and 97 (12%) for moderate to severe depression (CES-D > or =27). Survival analyses, controlling for age, sex, number of grafts, diabetes, smoking, left ventricular ejection fraction, and previous myocardial infarction, showed that patients with moderate to severe depression at baseline (adjusted hazard ratio [HR] 2.4, [95% CI 1.4-4.0]; p=0.001) and mild or moderate to severe depression that persisted from baseline to 6 months (adjusted HR 2.2, [1.2-4.2]; p=0.015) had higher rates of death than did those with no depression. INTERPRETATION: Despite advances in surgical and medical management of patients after CABG, depression is an important independent predictor of death after CABG and should be carefully monitored and treated if necessary.

Cause of Death↗

Carboplatin hypersensitivity reactions: re-treatment with cisplatin desensitisation.

OBJECTIVE: This aim of this study was to investigate the feasibility of re-treating patients who had experienced a hypersensitivity reaction to carboplatin with cisplatin following desensitisation. METHODS: Five patients with recurrent ovarian cancer who had a previous documented hypersensitivity reaction to carboplatin and a good clinical indication for continuing treatment with platinum were retreated following cisplatin desensitisation. All patients were rechallenged with cisplatin following a prolonged desensitisation protocol and the initial four patients then received subsequent cycles with a shortened protocol in an attempt to simplify and shorten the procedure. RESULTS: All five patients tolerated their first cycle of cisplatin on rechallenge using the full desensitisation protocol with no adverse reactions. Two patients received further treatments (one and three cycles) with a shortened protocol but treatment was terminated due to further adverse hypersensitivity reactions. Two patients received one further cycle with a shortened protocol and did not experience problems with hypersensitivity but treatment was stopped due to evidence of disease progression One patient received a further two cycles using the full desensitisation protocol without problems but treatment was stopped due to evidence of disease progression. CONCLUSIONS: A full cisplatin desensitisation protocol appears to be an effective way to re-treat patients who have previously experienced a hypersensitivity reaction to carboplatin. Attempts to shorten the procedure were associated with further allergic reactions, suggesting that the full protocol should be followed with each treatment.

Antineoplastic Agents↗

Physical activity, physiological, and psychomotor performance: a study of variously active older adult men.

This research examined varying levels of physical activity and psychomotor and physiological function in variously active older men. Very active moderately active, and low active participants were tested on simple (SRT) and choice reaction time (CRT), coincidence-anticipation timing (CAT), and VO2max. No significant differences for age or height were found, although percentage of fat, and weight were statistically different. Active groups were leaner and lighter. VO2max was significantly different between groups, as physically active groups yielded geater values. SRT and CAT also yielded significantly different results with more active participants showing better performance. No between-groups significant differences resulted for CRT. Generally, increased levels of physical activity were related to superior physiological outcomes and improved psychomotor peformance.

Aged↗

Biomonitoring of chemical exposure among New York City firefighters responding to the World Trade Center fire and collapse.

The collapse of the World Trade Center (WTC) on 11 September 2001 exposed New York City firefighters to smoke and dust of unprecedented magnitude and duration. The chemicals and the concentrations produced from any fire are difficult to predict, but estimates of internal dose exposures can be assessed by the biological monitoring of blood and urine. We analyzed blood and urine specimens obtained from 321 firefighters responding to the WTC fires and collapse for 110 potentially fire-related chemicals. Controls consisted of 47 firefighters not present at the WTC. Sampling occurred 3 weeks after 11 September, while fires were still burning. When reference or background ranges were available, most chemical concentrations were found to be generally low and not outside these ranges. Compared with controls, the exposed firefighters showed significant differences in adjusted geometric means for six of the chemicals and significantly greater detection rates for an additional three. Arrival time was a significant predictor variable for four chemicals. Special Operations Command firefighters (n = 95), compared with other responding WTC firefighters (n = 226), had differences in concentrations or detection rate for 14 of the chemicals. Values for the Special Operations Command firefighters were also significantly different from the control group values for these same chemicals and for two additional chemicals. Generally, the chemical concentrations in the other firefighter group were not different from those of controls. Biomonitoring was used to characterize firefighter exposure at the WTC disaster. Although some of the chemicals analyzed showed statistically significant differences, these differences were generally small.

Air Pollutants, Occupational↗

Comparing the performance of various advanced oxidation processes for treatment of acetone contaminated water.

Removal of low levels of organic pollutants can be quite challenging to many water treatment processes. Ketones, such as acetone, are often found in groundwaters and wastewaters at levels too low for supporting a bioreactor, yet since acetone is so soluble, it does not adsorb onto activated carbon very well, nor does it volatilize from water influent using air stripping. This study was undertaken to evaluate three advanced oxidation processes for their comparative ability to remove acetone from aqueous media. Optimization of the oxidation processes was attempted via adjustments of oxidizer inputs. The results indicated that all of the AOPs tested showed promise for removing acetone from water; however, ozonated systems undergoing UV photolysis achieved the highest rate and extent of treatment observed.

Acetone↗

Posttreatment visual acuity in patients treated with episcleral plaque therapy for choroidal melanomas: dose and dose rate effects.

PURPOSE: To determine the relationship between the long-term visual function and the dose and dose rates delivered to critical ocular structures in patients with choroidal melanoma treated with 125I episcleral plaque radiotherapy. MATERIALS AND METHODS: From 1987 to 1994, 63 patients underwent 125I episcleral plaque (Collaborative Ocular Melanoma Study [COMS] design) application for the treatment of choroidal melanoma. The mean tumor height was 4.5 mm (range 1.7-8.3). Doses and dose rates at the tumor apex, macula, and optic disc were calculated. Forty-three records were scored to assess whether a decrease in visual acuity of >2 lines on a standard Snellen eye chart had occurred. Patient age and the presence of hypertension or diabetes were noted. Statistical analysis was performed to assess both the rate at which visual decline had occurred and the presence of significant factors that had contributed to this decline. RESULTS: With a median follow-up of 36 months, the 3-year actuarial survival rate was 93.6%. The 3-year actuarial local control rate was 86.9%. The median time to visual loss after therapy was 18.7 months. The 3-year actuarial rate of visual preservation was 40.5%. Multivariate analysis demonstrated higher macula dose rates (p = 0.003) to forecast visual decline. Macula dose rates of 111 +/- 11.1 cGy/h were associated with a 50% risk of significant visual loss. CONCLUSION: Patients in our series treated with 125I plaque brachytherapy for choroidal melanoma experienced favorable tumor control, but with a measurable incidence of visual decline. Higher dose rates to the macula correlated strongly with poorer posttreatment visual outcome. This information may be valuable in selecting the optimal dose rates to treat choroidal melanomas and to predict the risk of visual decline.

Adult↗

How to cook up a healthy summer camp.

This article is designed to help school nurses plan a children's summer camp. In many ways, it is like a recipe, filled with tried experiences leading to success. Many of the ideas in this article may help others to brainstorm about implementing a camp. The idea for this summer camp originated from an obesity study conducted during the school year. In that study, it was found a large number of students were obese, and the majority of them spent a considerable amount of time in sedentary activities. In addition, the study questionnaire findings indicated that the children were not eating enough fruits or vegetables and had diets with high carbohydrate and fat content. Therefore, the major objective for the summer camp was to introduce the children to structured exercise and nutrition classes. Evaluation indicated the children profited socially, physically, and intellectually from the camp's activities.

Camping↗

Arterial perforation during infrainguinal lower limb angioplasty does not worsen outcome: results from 1409 patients.

PURPOSE: To assess the prevalence and clinical significance of arterial perforation during lower limb angioplasty and determine the outcome of patients suffering this complication. METHODS: The radiology department records of 1409 patients (878 men; mean age 69.6 years) undergoing peripheral angioplasty in 1532 limbs between January 1996 and December 1998 were studied to identify patients with a perforated vessel. RESULTS: Fifty-two (3.7%) perforations occurred. Patients with a perforation were significantly older (median 74.8 years versus 69.6, p=0.03) and were more likely to be diabetic (p=0.01). The median age of a smoker with a perforation was 68 years versus 78 years for nonsmokers (p=0.02). Among the perforations, 29 resolved without intervention, 6 required temporary balloon occlusion, 15 were coil embolized, and 2 needed both balloon and coil treatment. Twenty-four (46%) of the 52 patients had a clinically successful angioplasty despite the perforation. No patient needed further urgent intervention. Seven patients underwent subsequent surgery to treat the underlying vascular disease that had prompted treatment initially; no one was treated for complications of the perforation. Due to the more extensive nature of the procedure, subintimal angioplasty was associated with an unsurprising increase in the rate of perforation (RR, 2.06; 95% CI, 1.19-3.56; p=0.01). In no case did the perforation prejudice the eventual outcome of the patient. CONCLUSIONS: Arterial perforation during angioplasty is more common in the elderly and in diabetics. The perforation itself does not influence the ultimate outcome of the case; rather, it is the underlying vascular pathology.

Aged↗

A close-up look at an implant fracture: a case report.

The authors report on the fracture of a standard endosseous dental implant 11 years after placement. It had been connected to a natural tooth using a nonrigid connector to compensate for the lack of a built-in antirotational system on the prosthetic abutment of the implant restoration. Scanning electron microscopy revealed striations on the fracture surface, suggesting a fatigue-associated failure.

Crowns↗

Brugada syndrome as the cause of syncope in a 49-year-old man.

We report the case of a 49-year-old man in whom a diagnosis of Brugada syndrome was made after he presented to the emergency department for evaluation of a syncopal episode. The diagnosis was made by ECG changes, after the characteristic findings of peculiar downsloping ST-segment elevation in leads V(1) and V(2) and QRS morphology resembling a right bundle branch block were identified. Emergency physician recognition of this syndrome and its ECG findings is essential, because without treatment the incidence of sudden cardiac death in these patients is high.

Adult↗

Microenvironment in Ventilated Animal Cages with Differing Ventilation Rates, Mice Populations, and Frequency of Bedding Changes.

The purpose of the study was to assess the microenvironment in separately ventilated mouse cages at differing ventilation rates, mice populations, and frequency of bedding changes. We monitored intracage temperature, relative humidity, and concentrations of ammonia and carbon dioxide during 3 experiments. First, the effect of ventilation rate on the microenvironment of cages housing adult male mice was evaluated at 30, 40, 60, 80 and 100 air changes/h. For all ventilation rates tested, ammonia concentration was less than 3 ppm, carbon dioxide concentration ranged from 840 to 3,300 ppm, relative humidity ranged from 42 to 65%, and temperature ranged from 23.2 to 25.3 C. Second, we monitored cage microenvironment continually in experiments during which changing of bedding was delayed. Male mice were used in the experiment, and cages were ventilated (60 air changes/h). Cages were allowed to accumulate soiled material for 26 days, during which time ammonia concentration and relative humidity did not exceed 10 ppm and 45%, respectively. Third, we tested ventilation rate and frequency of bedding changes in ventilated cages containing breeding trios (2 females, 1 male) and their pups. Ammonia concentrations remained at 25 ppm or less for 30, 60, and 100 air changes/h when bedding was changed weekly and for 100 air changes/h when bedding was changed every 2 weeks. We concluded that 30 air changes/h was sufficient to maintain a healthful microenvironment in cages that were housing adult male mice in which bedding was changed weekly. When frequency of bedding changes was reduced to every 2 weeks, 60 air changes/h was sufficient for cages housing adult males, but 100 air changes/h was necessary for cages housing breeding trios and pups.

Journal Article↗