Magnetic resonance imaging in neonatal hemochromatosis--are we there yet?
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Hemochromatosis↗
Biomedical subjects
Helen Williams
Publications and source records attributed to Helen Williams.
Plaque rupture after short periods of fat feeding in the apolipoprotein E-knockout mouse: model characterization and effects of pravastatin treatment.
BACKGROUND: These studies examined the early time course of plaque development and destabilization in the brachiocephalic artery of the apolipoprotein E-knockout mouse, the effects of pravastatin thereon, and the effects of pravastatin on established unstable plaques. METHODS AND RESULTS: Male apolipoprotein E-knockout mice were fed a high-fat, cholesterol-enriched diet from the age of 8 weeks. Animals were euthanized at 1-week intervals between 4 and 9 weeks of fat feeding. Acutely ruptured plaques were observed in the brachiocephalic arteries of 3% of animals up to and including 7 weeks of fat feeding but in 62% of animals after 8 weeks, which suggests that there is a sharp increase in the number of plaque ruptures at 8 weeks. These acute plaque ruptures then appear to heal and form buried fibrous caps; after 9 weeks of fat feeding, mice had 1.05+/-0.15 buried fibrous caps at a single site in the brachiocephalic artery. Pravastatin (40 mg/kg of body weight per day for 9 weeks; resultant plasma concentration 16+/-4 nmol/L) had no effect on plasma cholesterol concentration in fat-fed apolipoprotein E-knockout mice but reduced the number of buried fibrous caps by 43% (P<0.0001). In longer-term experiments, the delay of pravastatin treatment until unstable plaques had developed reduced the incidence of acute plaque rupture by 36% (P<0.0001). CONCLUSIONS: Plaque rupture occurs at high frequency in the brachiocephalic arteries of male apolipoprotein E-knockout mice after 8 weeks of fat feeding. Pravastatin treatment inhibits early plaque rupture and is also effective when begun after unstable plaques have developed.
Animals↗
Evidence for persistence of adenovirus in the tear film a decade following conjunctivitis.
Chronic papillary conjunctivitis has been described following adenoviral conjunctivitis. It is unknown however, how long adenovirus is able to persist in the tear film and conjunctiva. To determine if adenovirus persists in the ocular surface following adenoviral conjunctivitis, 304 patients with a history of adenovirus conjunctivitis from whom an adenovirus had been isolated 10 years previously were sent a questionnaire regarding persistent or recurrent symptoms and were invited to attend. Patients were examined and samples of tears and conjunctival cells were collected from both eyes using tear film washes, filter paper, and swabs, the latter for virus isolation. Extracted DNA from the ocular samples was amplified using primers for herpes simplex virus (thymidine kinase) and adenovirus (hexon) genes. Adenovirus amplicons were sequenced and compared to original serotype. Thirty patients attended, 19 of whom had persistent papillary conjunctivitis. Evidence of adenovirus DNA was detected in 17 of 30 patients, 15 of whom also had evidence of a chronic papillary conjunctivitis. Adenovirus DNA was significantly associated with papillary conjunctivitis (P = 0.03). Adenovirus amplicons were successfully sequenced from six patients. Four patients harbored type 3 adenovirus, the same serotype with which they were infected originally 10 years previously. Two patients were infected originally with adenovirus serotype 3 but the current serotype was type 4. Infection of the ocular surface with adenovirus may predispose to the development of a persistent or recurrent conjunctivitis, the presence of which, appears to be associated with evidence of long term persistence of adenovirus DNA.
Adenovirus Infections, Human↗
Splenic state in surviving patients with visceral heterotaxy.
AIM: To identify patients with visceral heterotaxy who are at risk from fulminant sepsis. METHODS: We studied 38 patients, 37 having undergone abdominal ultrasound, all 38 having examination of blood films to establish presence of Howell-Jolly bodies, and all 38 documented to have had pneumococcal vaccination and prophylaxis with penicillin. We checked whether the parents were aware of the splenic state of their child, and when possible, we compared current results of blood films with those obtained postnatally. RESULTS: Two of the 17 patients with multiple spleens, all 11 without a detectable spleen, and 1 of 9 patients with a normal spleen, showed Howell-Jolly bodies in their blood films. In 5 of 23 patients with serial blood films, Howell-Jolly bodies had not been seen postnatally, but could now be detected in current blood films. Of these patients, 2 had multiple spleens, 1 did not have a spleen, and 1 had a solitary spleen of normal size. In the other patient, ultrasound could not be performed. Only one of these patients was receiving penicillin prophylactically, and had received pneumococcal vaccination. Of the 15 patients in whom Howell-Jolly bodies were present in the blood, only 8 parents knew about the potential risk for infection. Another 7 parents were sure that their child was taking penicillin regularly, and had received pneumococcal vaccination. CONCLUSIONS: Howell-Jolly bodies can be found in the blood of patients with visceral heterotaxy independent of the anatomical state of the spleen. As Howell-Jolly bodies can be encountered in the blood of such patients with increasing age, those with multiple and solitary spleens should be monitored regularly to identify those at risk. Parental knowledge of the splenic state, and compliance for prophylaxis using penicillin, and pneumococcal vaccination, were unsatisfactory in our cohort.
Abdomen↗
Absence of bacterial and viral DNA in bladder biopsies from patients with interstitial cystitis/chronic pelvic pain syndrome.
PURPOSE: We examined bladder biopsies from women with interstitial cystitis/chronic pelvic pain syndrome (IC/CPPS) for the presence of bacterial and viral DNA sequences using polymerase chain reaction. MATERIALS AND METHODS: Bladder biopsies were taken during cystoscopy from patients under investigation for IC/CPPS, or controls undergoing colposuspension for stress incontinence. Biopsies were snap frozen to -70C. After DNA extraction, polymerase chain reaction (PCR) using specific primers for the hypoxanthine-guanine phosphoribosyl transferase gene confirmed the presence of human DNA. PCR for bacterial and viral gene sequences was performed using specific primers. Positive reactions were repeated to confirm the signal. RESULTS: A total of 92 patients with IC/CPPS (12 who met the National Institute of Diabetes and Digestive and Kidney Diseases criteria and 80 who did not) and 91 controls were recruited. PCR for hypoxanthine-guanine phosphoribosyl transferase gene was positive in all samples. PCR for the 16S ribosomal RNA gene, as well as for adenovirus, cytomegalovirus, herpes simplex virus types I and II, human papillomavirus (all subtypes) and Chlamydia trachomatis were negative in all samples. CONCLUSIONS: IC/CPPS is not associated with persistence of viral and bacterial DNA in the bladder. A chronic infective etiology for the condition is excluded by these findings.
Chronic Disease↗
Characteristics of intact and ruptured atherosclerotic plaques in brachiocephalic arteries of apolipoprotein E knockout mice.
The brachiocephalic arteries of fat-fed apolipoprotein E knockout mice develop plaques that frequently rupture and form luminal thromboses. The morphological characteristics of plaques without evidence of instability or with healed previous ruptures (intact) and vessels with acutely ruptured plaques (ruptured) have now been defined, to understand the process of plaque destabilization in more detail. Ninety-eight apolipoprotein E knockout mice were fed a diet supplemented with 21% lard and 0.15% cholesterol, for 5 to 59 weeks. Of these 98 mice, 51 had an acutely ruptured plaque in the brachiocephalic artery. Ruptured and intact plaques differed in terms of plaque cross-sectional area (intact, 0.109+/-0.016 mm2; ruptured, 0.192+/-0.009 mm2; P=0.0005), luminal occlusion (intact, 35.3+/-3.3%; ruptured, 57.7+/-1.9%; P<0.0001), the number of buried caps within the lesion (intact, 1.06+/-0.12; ruptured, 2.66+/-0.16; P<0.0001), fibrous cap thickness (intact, 4.7+/-0.6 microm; ruptured, 2.0+/-0.3 microm; P=0.0004), and lipid fractional volume (intact, 35.9+/-3.0%; ruptured, 50.7+/-2.2%; P=0.0019). This study confirms that plaque rupture is a frequent occurrence in the brachiocephalic arteries of apolipoprotein E knockout mice on a high-fat diet. The data also show that ruptured plaques in these mice show many of the characteristics of vulnerable plaques in humans. This supports the use of this model in studies of the mechanisms and therapy of plaque rupture.
Animals↗
Animal models of spontaneous plaque rupture: the holy grail of experimental atherosclerosis research.
Throughout the history of atherosclerosis research we have sought animal models of the disease process that exhibit high frequencies of the features that make human plaque a clinical risk: plaque rupture, mural thrombosis, and intra-plaque hemorrhage. This type of model is needed to determine the mechanisms by which plaques rupture and to design and test therapeutic interventions for stabilizing plaques. Studies of domestic and exotic animals have shown that most species will spontaneously develop fatty streaks and in some cases atheromatous lesions with sufficient time, but that rupture and thrombosis is exceedingly rare. Even with addition of fat and cholesterol to the diet, lesion development is accelerated but does not increase the frequency with which plaques rupture in most animal models. However, recently we have observed high frequencies of intra-plaque hemorrhage in the innominate/brachiocephalic arteries of older, chow-fed, hyperlipidemic, apolipoprotein E-deficient mice, and high frequencies of plaque rupture with mural thrombus in younger apolipoprotein E-deficient mice fed a high-fat diet. This suggests that plaque rupture and secondary thrombosis are frequent and reproducible occurrences at specific sites in apolipoprotein E-deficient mice, and that the timing and pathobiology of the ruptures are influenced by lipid status in this murine model.
Animals↗
Evaluation of explicit prioritisation for elective surgery: a prospective study.
OBJECTIVES: To evaluate whether the Clinical Priority Assessment Criteria (CPAC), used to prioritise access to elective surgery, was associated with: (a) patients' access to surgery in practice; (b) patients' level of need; and (c) patients' ability to benefit from surgery. Patients' perceptions of the 'booking system' for surgery were also explored. METHODS: Prospective cohort study in New Zealand. Consecutive patients assessed for cataract (n = 101), prostate (n = 103) or hip or knee joint replacement (n = 137) surgery were interviewed close to the time of their CPAC prioritisation, and then six and 12 months later. RESULTS: CPAC scores were associated with access to surgery. There were weak-to-moderate correlations between CPAC scores and disease-specific health status before surgery (need) but almost no correlations with improvement in health status following surgery (ability to benefit). Change in health status was highly correlated with pre-surgery health status. Many patients supported prioritisation according to need, although the impersonal nature of the scoring system and the changing thresholds for surgery distressed some. CONCLUSIONS: While prioritisation systems for surgery have potential value the CPAC criteria investigated need modification. Ability to benefit should receive increased weight. The impact of an explicit prioritisation system upon the doctor-patient relationship needs to be explored as there is some evidence that it may impede the discussion of the risks and benefits of surgery, and of the treatment preferences of patients.
Elective Surgical Procedures↗