Bacterial biofilms and capsular contracture in patients with breast implants.

BACKGROUND: It has been hypothesized that bacterial biofilms on breast implants may cause chronic inflammation leading to capsular contracture. The association between bacterial biofilms of removed implants and capsular contracture was investigated. METHODS: Breast implants explanted between 2006 and 2010 at five participating centres for plastic and reconstructive surgery were investigated by sonication. Bacterial cultures derived from sonication were correlated with patient, surgical and implant characteristics, and the degree of capsular contracture. RESULTS: The study included 121 breast implants from 84 patients, of which 119 originated from women and two from men undergoing gender reassignment. Some 50 breast prostheses were implanted for reconstruction, 48 for aesthetic reasons and 23 implants were used as temporary expander devices. The median indwelling time was 4·0 (range 0·1-32) years for permanent implants and 3 (range 1-6) months for temporary devices. Excluding nine implants with clinical signs of infection, sonication cultures were positive in 40 (45 per cent) of 89 permanent implants and in 12 (52 per cent) of 23 temporary devices. Analysis of permanent implants showed that a positive bacterial culture after sonication correlated with the degree of capsular contracture: Baker I, two of 11 implants; Baker II, two of ten; Baker III, nine of 23; and Baker IV, 27 of 45 (P < 0·001). The most frequent organisms were Propionibacterium acnes (25 implants) and coagulase-negative staphylococci (21). CONCLUSION: Sonication cultures correlated with the degree of capsular contracture, indicating the potential causative role of bacterial biofilms in the pathogenesis of capsular contracture. REGISTRATION NUMBER: NCT01138891 (http://www.clinicaltrials.gov).

Lake Erie College of Osteopathic Medicine's independent study pathway program: an alternative medical school curriculum design.

Lake Erie College of Osteopathic Medicine has developed an independent study pathway as an alternative to the traditional medical school curriculum design. Beginning with the 2001-2002 academic year, three equivalent and distinct curriculum pathways will be available to medical students at the Lake Erie College of Osteopathic Medicine: the lecture/discussion pathway, the problem-based learning pathway, and the independent study pathway (ISP). The ISP program will provide flexibility for students during their preclinical years. Using highly structured faculty-developed modules, students in the ISP program will be responsible for their own learning in a self-directed, independent manner, including when, where, what, and how to study. Examinations will be taken when students consider themselves ready. If examinations reveal deficiencies in student preparation, these deficiencies must be remedied before students continue their studies. Faculty will be available, as needed, to assist the students through difficult concepts and material.

Transient basophilia following the application of lymphatic pump techniques: a pilot study.

Lymphatic pump techniques (LPTs) consisting of pectoral traction and splenic pump were performed on seven male medical students following blood collection for baseline value determinations. Blood was collected from each subject at 15, 30, 60, 120, and 240 minutes post-LPT. The samples were analyzed for serum chemistry and complete blood cell count. All subjects showed an increase in the percentage of basophils. There was variation in the time points for the initial occurrence of basophilia among the subjects. A separate cohort of five male medical students served as control subjects. The control group did not receive LPTs. Blood samples collected at the same time points as the experimental group did not show the basophilia.

Topical application of WR-2721 achieves high concentrations in the rectal wall.

Rectal wall injury is an important treatment-related morbidity in patients treated with radiation for prostate cancer. We have undertaken this study to investigate the merits of topical intrarectal application of the radioprotective compound WR-2721. Male Copenhagen rats were injected intrarectally with 2% WR-2721 gel. At 10, 20, 30 and 40 min after application, a laparotomy was performed, and the rectum and prostate were removed. Concentrations of total WR-1065 (the active metabolite of WR-2721) were determined in these samples by an HPLC assay. While the concentration in the rectal wall tended to increase with time, it did not change substantially in the prostate. The concentration in the rectal wall was found to be significantly higher at all times. We conclude that preferential accumulation of WR-2721 in the rectal wall can be achieved by topical application. This is a promising approach to modifying rectal wall tolerance that deserves more study.

New understanding from Cf brachytherapy trials and considerations for neutron therapy of bulky gyn carcinoma for future.

PURPOSE: This study reviews the radiobiology of neutrons and the results and methods that have evolved in the Cf-252 neutron brachytherapy trials to postulate methods to explore for their potential applicability to fast neutron beam therapy. METHODS AND MATERIALS: The results of radiobiological experimental studies are reviewed for RBE for different fraction number and dose per fraction. RBE was always higher for fractionated neutrons based on comparison with isoeffective doses of photons. This is inherent in the basic radiobiological properties of photons. RBE was highest for low dose rate (LDR) Cf brachytherapy. RESULTS: Brachytherapy methods deliver radiation dose which is localized and conformal to the tumor. These methods have been used for Cf therapy and led to good tissue tolerance and local tumor control. The use of large dose/session (or fraction), small fraction number, short treatment times, followed by photon beam therapy has been the practice in Cf brachytherapy. It has been found that bulky or localized advanced tumors responded better if neutron treatment preceded the photon beam therapy. Therapeutic efficacy is dependent on the fraction size of neutrons and not the time duration of application. CONCLUSIONS: Available radiobiological data on neutron RBE with fraction number and size of dose and the favorable experience from Cf brachytherapy with up-front neutron applications suggest new avenues to explore for the neutron beam trials. The high efficacy noted for small volume dose, 10 to 20 Gy-eqs of dose per session, localized dose, conformal methods, small number of sessions, short treatment times and an up-front or early schedule in combining neutron and photon therapy suggests that similar schedules and methodology may also be effective for neutron beam therapy. Further clinical trials are indicated and bulky GYN tumors represents suitable tumors for study.

Administration of L-2-oxothiazolidine-4-carboxylate increases glutathione levels in rat brain.

Sterile L-2-oxothiazolidine-4-carboxylate, given as a neutral 100 mmol solution at a dose of 8 mmol/kg subcutaneously, caused an increase in total glutathione concentration in the brain of treated rats. This finding could be important in understanding the role of glutathione in the central nervous system.

Respiratory depression in goats by stable xenon: implications for CT studies.

The pharmacology of stable xenon is of practical importance to users of the xenon CT-regional cerebral blood flow method. In a study in goats we have demonstrated that xenon has a characteristic respiratory depressant effect, unlike effects of comparable anesthetic concentrations of nitrous oxide and halothane.

The ferret as a model for endogenous synthesis and metabolism of N-nitrosamines.

We have begun to evaluate the ferret as a model for studying gastric nitrosation and nitrosamine metabolism. Jugular cannulation allows convenient dosing and sampling of blood, and this technique has been used to study clearance of N-nitrosodimethylamine (NDMA) after intravenous, intraperitoneal and intragastric administration. NDMA metabolism can be inhibited by 4-methylpyrazole for up to 24 h; the accumulation of endogenously-synthesized NDMA can therefore be observed in animals following pretreatment with this compound. We have studied endogenous NDMA synthesis in animals dosed with dimethylamine and nitrite and in animals to which no NDMA precursors were administered.

Pulmonary function changes in goats given 3-methylindole orally.

Six adult goats were given 0.2 g of 3-methylindole (3MI)/kg of body weight orally. Lung mechanics and ventilatory function were obtained before 3MI and 2, 4, 6, 24, 48, and 72 hours after 3MI administration. Clinical signs were also monitored. Lungs were removed for gross and microscopic examination and for morphometric analysis from goats that died spontaneously or were killed with an overdose of pentobarbital after 72 hours. The major pulmonary function changes observed included a marked decrease in dynamic lung compliance with a moderate increase in airway resistance, a concomitant hypoxemia, sustained increase in respiratory frequency, a progressive decrease in tidal volume and alveolar ventilation, and increased dead space to tidal volume ratio. A mild metabolic acidosis was also noticed.

The effects of unilateral carotid body excision on ventilatory control in goats.

The purpose of this study was to determine whether or not unilateral carotid body excision (UCBE) alters normal respiratory control in awake and otherwise intact goats. We measured resting VE and blood gas tensions and pH and ventilatory responses (VR) to NaCN, dopamine and Doxapram in awake goats before and after UCBE. Resting ventilation, blood gas tensions and pH, and the VR to the above stimuli were not altered by UCBE. During exposure to hypoxia in a hypobaric chamber (PB = 450 torr), PaCO2 decreased in UCBE goats over the first hour, indicating acute hypoxic hyperventilation. During the subsequent 8 h, PaCO2 decreased an additional 5-6 torr, suggesting ventilatory acclimatization to chronic hypoxia (VACH). The response was similar to that observed in intact goats. Acute normoxia following 6 and 8 hr did not completely alleviate the hypocapnia of prolonged hypoxia, further suggesting VACH. We conclude that sufficient redundancy exists in the inputs from the paired carotid body chemoreceptors so that normal ventilatory responsiveness to acute and chronic stimuli is present in goats possessing only a single carotid body.

Role of the carotid body in hyperpnea of moderate exercise in goats.

In the present study the ventilatory response to exercise was measured in goats before and after carotid body excision (CBE) (n = 7) or sham operation (n = 1). Nine-minute periods of moderate treadmill walking were carried out under three conditions: 4.8 kph, 0% grade during normoxia and hypoxia (arterial O2 tension approximately 43 Torr) and 4.8 kph, 5% grade during normoxia. Ventilatory variables, metabolic rate, and arterial blood acid-base and blood gases were measured at 30-s intervals for the first 3 min and again during the 6th and 9th min of exercise. In normal goats during exercise in normoxia, ventilation changed in proportion to changes in metabolic rate resulting in arterial CO2 tension (PaCO2) and arterial pH (pHa) homeostasis throughout exercise. CBE resulted in nearly equivalent hypoventilation during steady-state rest and exercise (delta PaCO2 approximately equal to 5--7 Torr) during normoxia and loss of the positive interaction between hypoxia and exercise. There was also a significant disruption of PaCO2-pHa homeostasis during the first 30 s of exercise after CBE when PaCO2 was 3 Torr below rest and pHa was 0.03 units above rest. Our data indicate: 1) that the carotid chemoreceptors may contribute a similar proportional drive to breathe during rest and exercise; 2) that transient hyperventilation at the onset of exercise after CBE may indicate an important neural drive to breathe that is normally damped by intact peripheral chemoreceptors; and 3) that the mechanism linking ventilation to CO2 production remains intact after CBE.