Dental intervention for the irradiated patient: time to re-evaluate dental treatment algorithms?

Modern radiotherapy delivery systems and treatment strategies are aimed at limiting the irradiation of healthy structures in the head and neck. This seeks to mitigate post-treatment toxicities and complications such as osteoradionecrosis of the jaw. Given the changes to radiotherapy, conventional workflows for the management of patients requiring dentoalveolar surgery may no longer be suitable. It may therefore be appropriate to revisit current treatment algorithms for the management of patients with radiotherapy to the jaws who require dentoalveolar surgery. At present, there are poor data on this. Development of a randomised trial may be warranted to establish the true relative risk for extraction of teeth in the setting of modern radiation therapy delivery systems.

High temperature pyrolysis of 2-methyl furan.

The dissociation of 2-methyl furan at high temperatures has been studied in a combined experimental and theoretical approach to elucidate the details of this multi-channel unimolecular reaction. Laser schlieren densitometry studies were performed in a diaphragmless shock tube over the range 1600 < T < 2300 K and three pressures 60, 120 and 240 Torr. The theoretical study identified many reaction paths, most of which are initiated by the formation of carbenes. Of these paths, five account for 99% consumption of 2MF, and three account for 95% consumption. Simulations of the experimental results with a model that incorporated the theoretical predictions of reaction paths failed to reproduce the experimental data. This was resolved by increasing the rate of loss of an H-atom from the methyl group in 2-methyl furan by a factor of 2-4. The resulting model provides good simulations of the complete set of experimental data. The branching fractions for the three key reactions are both temperature and pressure dependent.

Note: An improved driver section for a diaphragmless shock tube.

Improvements to equipment lifetime and measurement reproducibility have been made by modifying the actuating mechanism of a diaphragmless shock tube that is used for high temperature gas kinetic studies. The modifications have two major benefits while retaining the simplicity of the original apparatus. First, the reproducibility of shock wave generation has been greatly improved and is demonstrated with 50 nearly identical experiments on the dissociation of cyclohexene at T2 = 1765 ± 13 K and P2 = 120 ± 1 Torr, demonstrating the capability for signal averaging over many experiments. Second, the lifetime of the bellows which forms the heart of the actuator is considerably improved, significantly increasing the time between replacements.

Theory of hyperspherical Sturmians for three-body reactions.

In this paper we present a theory to describe three-body reactions. Fragmentation processes are studied by means of the Schrodinger equation in hyperspherical coordinates. The three-body wave function is written as a sum of two terms. The first one defines the initial channel of the collision while the second one describes the scattered wave, which contains all the information about the collision process. The dynamics is ruled by an nonhomogeneous equation with a driven term related to the initial channel and to the three-body interactions. A basis set of functions with outgoing behavior at large values of hyperradius is introduced as products of angular and radial hyperspherical Sturmian functions. The scattered wave is expanded on this basis and the nonhomogeneous equation is transformed into an algebraic problem that can be solved by standard matrix methods. To be able to deal with general systems, discretization schemes are proposed to solve the angular and radial Sturmian equations. This procedure allows these discrete functions to be connected with the hyperquatization algorithm. Finally, the fragmentation transition amplitude is derived from the asymptotic limit of the scattered wave function.

Giving patients information on abnormal cytology and human papillomavirus: survey of health providers.

OBJECTIVES: Knowledge of the link between HPV and cervical cancer is low among women. Health providers may be required to give information and counseling on HPV. This study surveyed health providers' comfort in counseling women about HPV. METHODS: Physicians, nurses and midwives attending a lecture on HPV completed a questionnaire (before the lecture) on their comfort level answering questions that a woman with an abnormal Pap may ask her health provider. Comfort level with knowledge was assessed on a 7-point Likert scale, with seven being very comfortable. RESULTS: Of the 96 attendees, 57.3% (55/96) were eligible and completed the questionnaire. Two-thirds of respondents were physicians (61.8%; 34/55), 38.2% were nurses or midwives (21/55). Telling a partner about HPV infection was the question about which the most respondents were very comfortable (69.1% answering 6 or 7) and chances of developing cervical cancer was the item about which the fewest respondents reported being very comfortable (36.4%). CONCLUSIONS: Less than one-half to two-thirds of health providers self-reported being very comfortable answering HPV-related questions that a woman may ask. More information is needed regarding health providers' actual knowledge of HPV and women's wishes for information.

Economic evaluation of hybrid capture human papillomavirus testing in women with low-grade papanicolaou smear abnormalities.

OBJECTIVES: Our aim was to determine the cost-effectiveness of three strategies for detecting cervical intraepithelial neoplasia 2 and 3 after a determination of atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion on screening Papanicolaou (Pap) smear. METHODS: Single repeat Pap smear. Hybrid Capture testing for human papillomavirus, and immediate colposcopy were compared. A theoretical decision analysis model was constructed with 10,000 women in each group. Costs and outcomes are those of diagnosis and treatment of cervical intraepithelial neoplasia (CIN) 2 or 3. Outcome probabilities and utilization data were obtained from a literature review and expert opinion. RESULTS: Repeat smear detected 1,125 cases, Hybrid Capture, 1,350 cases, and colposcopy, 1,482 cases of CIN2 or CIN3, costing $1,490,000, $1,980,000, and $2,420,000, respectively. Incremental cost per high-grade dysplasia was $2,178 for Hybrid Capture and $3,333 for colposcopy. Sensitivity analyses that test management efficiencies are reported. CONCLUSIONS: More effective strategies are more costly. However, if costs saved by preventing invasive cancers are included, all three strategies may be cost-saving.

Successful treatment of a patient with chronic Lyme arthritis with extracorporeal photochemotherapy.

We report the use of photopheresis in a patient with chronic Lyme arthritis with apparent resolution of the signs and symptoms. Further controlled trials will be required to determine whether there is a therapeutic role for photopheresis in this disease.

Calcium carbonate exacerbates glomerular capillary hypertension and injury in rats with desoxycorticosterone-salt hypertension.

To examine the effects of dietary calcium supplementation on systemic and renal hemodynamics and glomerular injury in experimental hypertension, rats with desoxycorticosterone-salt hypertension were fed either standard chow, containing 1% calcium by weight, or chow supplemented with calcium carbonate to achieve a calcium content of 2% by weight. Ingestion of calcium carbonate failed to reduce systemic blood pressure, but was associated with increased proteinuria and morphologic evidence of glomerular injury. Micropuncture studies revealed that afferent arteriolar resistance was reduced and glomerular capillary pressure further increased in the high calcium group. Thus, calcium carbonate, in moderate amounts, not only failed to ameliorate systemic hypertension but, paradoxically, worsened intrarenal hypertension and injury in rats with mineralocorticoid-induced hypertension.

Glomerular hypertension and injury in desoxycorticosterone-salt rats on antihypertensive therapy.

Uninephrectomized male Munich-Wistar rats received either weekly subcutaneous injections of vehicle and water for drinking; injections of desoxycorticosterone (DOC) and 1% saline (SALT) for drinking; or DOC and SALT with hydrochlorthiazide, hydralazine, reserpine and KCl added. All studies were performed six weeks after UNX. At that time, rats receiving DOC and SALT alone were hypertensive and had significantly more proteinuria and morphologic evidence of glomerular injury than rats given vehicle and tap water which were normotensive. Antihypertensive therapy normalized mean arterial pressure in DOC-SALT rats, but failed to prevent proteinuria, mesangial expansion or focal segmental glomerular lesions. Micropuncture studies revealed that glomerular capillary pressure was elevated in both untreated and treated DOC-SALT animals. We conclude that drugs which successfully reduce systemic blood pressure may fail to correct glomerular capillary hypertension in DOC-SALT rats. As persistence of intrarenal hypertension is associated with significant glomerular injury, normalization of glomerular capillary pressure rather than systemic arterial pressure is crucial to the prevention of glomerular injury in this model.