Influence of oxygen, albumin and pH on copper dissolution in a simulated uterine fluid

OBJECTIVES

The aim of this paper is to study the influence of albumin content, from 5 to 45 g/L, on copper dissolution and compounds composition in a simulated uterine solution.

METHODS

Experiments were performed in atmospheric pressure conditions and with an additional oxygen pressure of 0.2 atmospheres, at 6.3 and 8.0 pH values, and at a temperature of 37 +/- 0.1 degrees C for 1, 3, 7, and 30 days experimentation time.

RESULTS

The copper dissolution rate has been determined using absorbance measurements, finding the highest value for pH 8.0, 35 g/L albumin, and with an additional oxygen pressure of 0.2 atmospheres: 674 microg/day for 1 day, and 301 microg/day for 30 days. X-ray photoelectron spectroscopy (XPS) results show copper(II) as the main copper oxidation state at pH 8.0; and copper(I) and metallic copper at pH 6.3.

CONCLUSIONS

The presence of albumin up to 35 g/L, accelerates copper dissolution. For high albumin content a stabilisation on the copper dissolution takes place. Corrosion product layer morphology is poorly protective, showing paths through which copper ions can release.

Influence of pH and oxygen on copper corrosion in simulated uterine fluid

This paper studies the copper corrosion in simulated uterine fluids in the presence of urea and/or albumin, at pH 5.0, 6.3 and 8.0, with 0.10, 0.15 and 0.20 atmospheres of oxygen pressure and without additional oxygen pressure, at 37 degrees C temperature, and for 1, 3, 7, 15, 21 and 30 days experimentation. The copper dissolution rate was determined using absorbance measurements. Copper dissolution was the highest at pH 8.0 and 0.20 atmospheres of oxygen pressure, 674 microg d(-1) for 1 day and 109 microg d(-1) for 30 days. The presence of albumin, contrary to urea, accelerates copper corrosion.

Integrative medicine: a paradigm shift in medical education and practice

The use of alternative/complementary medicine has been increasing considerably. Conventional medicine must begin to address issues related to the use, safety, regulation, research and education of alternative/complementary medicine. Integrative medicine combines conventional medicine and alternative complementary practices. Integrative medicine is an innovative approach to medicine and medical education. It involves the understanding of the interaction of the mind, body and spirit and how to interpret this relationship in the dynamics of health and disease. Integrative medicine shifts the orientation of the medical practice from disease based approach to a healing based approach. It does not reject conventional medicine nor uncritically accepts unconventional practices. Integrative medicine is an effective, more fulfilling human approach to medicine based on the benefit of the patient by following good medicine practices in a scientific manner.

Aggressive therapy for locoregional recurrence after mastectomy in stage II and III breast cancer patients

BACKGROUND

To determine if aggressive treatment of locoregional recurrence affects survival, we retrospectively analyzed the clinical outcome of 69 breast cancer patients who developed locoregional disease as their first episode of recurrence following mastectomy and adjuvant chemotherapy.

METHODS

Patients were identified from among 1,707 stage II and III breast cancer patients who enrolled in five different doxorubicin-based adjuvant chemotherapy protocols at The University of Texas M. D. Anderson Cancer Center from 1975 to 1986. Sixty-nine evaluable patients who had a locoregional recurrence as the first site of relapse after mastectomy formed the study group. Multifactorial analysis of clinical and histopathological characteristics of both the primary tumor and the subsequent recurrence was performed using a logistic regression method. Survival analysis was performed using an actuarial life-table method calculated from the date of registration into the adjuvant therapy protocols.

RESULTS

Median follow-up was 6.6 years. Two factors significantly affected survival: recurrence of disease during or after adjuvant treatment of the primary and whether the patient was rendered disease free after recurrence.

CONCLUSIONS

Stage II and III breast cancer patients who have locoregional recurrence after adjuvant chemotherapy and can be rendered disease free may have a better survival rate. Aggressive treatment of locoregional recurrence including complete surgical excision should be considered in this subgroup of patients.

Enteric bacteria and ingested inert particles translocate to intraperitoneal prosthetic materials

Sterile and endotoxin-free biomaterials commonly used in prosthetic devices (Dacron velour, woven Dacron, and Biomer polyurethane) and cotton (control material) were implanted intraperitoneally in mice with normal enteric flora. Intraperitoneal Biomer and woven Dacron became contaminated with 100 to 10,000 enteric bacteria, including Escherichia coli, Pseudomonas aeruginosa, enterococci, and staphylococci species, within 3 days; intraperitoneal cotton and Dacron velour were contaminated within 24 hours. Mesenteric lymph nodes showed parallel incidences of translocation. The peritoneal cavity became contaminated only if the biomaterial itself became contaminated. No bacterial overgrowth, perforation, or histologic changes in the bowel were found. Subcutaneous biomaterials remained sterile. Ingested fluorescent beads appeared in enterocytes, in lamina propria within macrophages, and in intraperitoneal biomaterials. The data suggest that intraperitoneal sterile reactive stimuli can induce bacterial translocation to the dense prosthesis directly through the intact normal bowel wall. One of the mechanisms seems to involve phagocytosis of particles and bacteria within the bowel wall that are then chemotactically attracted to nearby sites of inflammation.

Biomaterial associated impairment of local neutrophil function

The effect of biomaterials on neutrophil function was studied in vitro to determine if these materials activated neutrophils and to determine the subsequent response of these neutrophils to further stimulation. Two biomaterials--polyurethane, a commonly used substance, and Velcro pile (used in the Jarvik 7 heart)--were evaluated. Two control substances, polyethylene and serum-coated polystyrene, were used for comparison. Neutrophil superoxide release was measured following incubation with these materials for 10, 30, and 120 min in the absence of additional stimulation and after stimulation with formylmethionylleucylphenylalanine (fMLP) or phorbol myristate acetate (PMA). The authors observed that the incubation of neutrophils on both polyurethane and Velcro resulted in substantially increased superoxide release that was greater after the 10 min than after the 30 or 120 min association. These activated neutrophils exhibited a poor additional response to fMLP but responded well to PMA. The effect of implantation of the Novacor left ventricular assist device on peripheral blood neutrophil function was also evaluated. The peripheral blood neutrophils exhibited normal superoxide release and chemotaxis. These studies suggest that biomaterials may have a profound local effect on neutrophils, which may predispose the patient to periprosthetic infection, but that the reactivity of circulating neutrophils is unimpaired.