Dry heat and microwave-generated steam protocols for the rapid decontamination of respiratory personal protective equipment in response to COVID-19-related shortages.

BACKGROUND: In the wake of the SARS-CoV-2 pandemic and unprecedented global demand, clinicians are struggling to source adequate access to personal protective equipment. Respirators can be in short supply, though are necessary to protect workers from SARS-CoV-2 exposure. Rapid decontamination and reuse of respirators may provide relief for the strained procurement situation. METHOD: In this study, we investigated the suitability of 70°C dry heat and microwave-generated steam (MGS) for reprocessing of FFP2/N95-type respirators, and Type-II surgical face masks. Staphylococcus aureus was used as a surrogate as it is less susceptible than enveloped viruses to chemical and physical processes. RESULTS: We observed >4 log10 reductions in the viability of dry S. aureus treated by dry heat for 90 min at 70°C and >6 log10 reductions by MGS for 90 s. After 3 reprocessing cycles, neither process was found to negatively impact the bacterial or NaCl filtration efficiency of the respirators that were tested. However, MGS was incompatible with Type-II surgical masks tested, as we confirmed that bacterial filtration capacity was completely lost following reprocessing. MGS was observed to be incompatible with some respirator types due to arcing observed around some types of metal nose clips and by loss of adhesion of clips to the mask. CONCLUSION: Considering the advantages and disadvantages of each approach, we propose a reprocessing personal protective equipment/face mask workflow for use in medical areas.

Metallosis following implantation of magnetically controlled growing rods in the treatment of scoliosis: a case series.

AIMS: We present a case series of five patients who had revision surgery following magnetic controlled growing rods (MGCR) for early onset scoliosis. Metallosis was found during revision in four out of five patients and we postulated a mechanism for rod failure based on retrieval analysis. PATIENTS AND METHODS: Retrieval analysis was performed on the seven explanted rods. The mean duration of MCGR from implantation to revision was 35 months (17 to 46). The mean age at revision was 12 years (7 to 15; four boys, one girl). RESULTS: A total of six out of seven rods had tissue metallosis and pseudo-capsule surrounding the actuator. A total of four out of seven rods were pistoning. There were two rods which were broken. All rods had abrasive circumferential markings. A significant amount of metal debris was found when the actuators were carefully cut open. Analytical electron microscopy demonstrated metal fragments of predominantly titanium with a mean particle size of 3.36 microns (1.31 to 6.61). CONCLUSION: This study highlights concerns with tissue metallosis in MCGR. We recommend careful follow-up of patients who have received this implant. Cite this article: Bone Joint J 2016;98-B:1662-7.

Phenylacetic acid halides inhibit estrogen receptor (ER)-positive MCF-7 cells, but not ER-negative human breast cancer cells or normal breast epithelial cells.

Phenylacetic acid (PA) derivatives and conjugates have been reported to have antiproliferative and antitumor properties against various types of cancers. Based on these findings, recent in vitro experiments were devised to examine the antiproliferative properties of a series of para substituted (Br, Cl, F, H, NO2 and OCH3) PAs. The in vitro screening protocal involved the plating of MCF-7 cells in a 96-well plate assay. After 1 day, the cells were exposed to the PA derivatives for 2 days (log phase of MCF-7 growth curve). Cells growth was determined by the Alamar blue dye reagent. The optical density data was analyzed and IC50 concentration values determined. The results showed that PA halide derivatives caused a significant decrease in proliferation of the MCF-7 cells. The order of antiproliferative activity was BR > Cl > or = F, with IC50 values (nM) of 10 +/- 0.005, 100 +/- 0.02 and 100 +/- 0.04, respectively. The OCH3, H and NO2 compounds showed no significant antiproliferative activity. PA halide derivatives may have similar actions as tamoxifen because they show specificity for estrogen receptor-positive cells.

The growth inhibitory properties of a dopamine agonist (SKF 38393) on MCF-7 cells.

Dopamine agonists have been indicated as treatment for disorders such as Parkinson's disease, cardiogenic shock and dopamine insufficiency. A unique relationship exists between dopamine and carcinogenicity. Chronic prolactin stimulation has been identified as a promoter of carcinogenicity. Prolactin secretion is regulated through dopamine receptor activation. Dopaminergic agonists inhibit prolactin release and antagonists increase release. High levels of prolactin have been shown to suppress production of estrogen and progesterone. As a result of these findings, a series of experiments were designed to examine the effects of a specific dopamine agonist, SKF 38393, against MCF-7 cells. MDA-MB231 and MCF-10 cells were used as negative controls. The breast cancer in vitro screening procedure involved the plating of MCF-7, MDA-MB231 and MCF-10 cells in a 96-well plate assay. After 1 day, the cells were exposed to SKF 38393 for 2 days and cell growth was determined by the Alamar blue dye reagent method. The optical density data was analyzed and IC50 values determined. The results indicated that SKF 38393 caused a significant decrease in proliferation of MCF-7 cells. The IC50 value was 0.1 +/- 0.03 microM. The results also indicated no significant effect on MDA-MB231 and MCF-10 cells.

Cadmium-induced sexual dysfunction does not involve increased hepatic metabolism of testosterone nor increased circulating levels of corticosterone.

Sexually experienced male rats were injected IP with 0, 0.3, 1.5, 3.0, or 6.0 mg/kg cadmium chloride. The highest dose was fatal within 48 h of injection. A dose-related deficit in erectile function was observed in ex copula tests 48 h after injection. Copulatory dysfunction was evident in mating tests 72 h after injection. Hepatic mixed function oxidase activity after 0.3 mg/kg injections was not different from controls, but was diminished by 50% in rats treated with 3.0 mg/kg. The higher cadmium doses (1.5 and 3.0 mg/kg) were associated with equivalent and marked reductions in circulating testosterone levels, and lesser decrements in circulating corticosterone levels. The rats treated with 1.5 or 3.0 mg/kg cadmium chloride lost weight (32 +/- 12 and 39 +/- 9 g, respectively). Relative decapsulated adrenal gland weights were markedly increased in rats treated with 3.0 mg/kg. These data indicate that exposure to cadmium is associated with alterations in sexual, hepatic, and adrenal function, with erectile dysfunction occurring at the lowest dose. The effects on copulatory behavior are especially striking because it requires some weeks for copulatory behavior to wane following castration.

The prevalence and nature of podiatric problems in elderly diabetic patients.

To determine if diabetes in the elderly is associated with increased prevalence of podiatric problems, a random sample of diabetic patients (n = 74) was compared to a group of elderly non-diabetic patients (n = 79). The two groups were comparable in age (range 70-90 years), smoking habits, and consumption of alcohol. The mean duration of diabetes was 14.5 +/- 11.7 years (+/- SD), and mean serum fructosamine level was 3.3 +/- 0.66 mmol/L. The number of medical diagnoses and medications used was significantly higher in the diabetic group. Diabetic patients had modestly higher prevalence of neuropathy, vascular disease, kidney disease, and eye complications. The most common podiatric problem in both groups was elongated toenails. The prevalence of podiatric problems such as cellulitis, amputation, tinea pedia, onychomycosis, calluses, bunions, and hammer toe deformity were not increased in diabetic patients. Active foot ulcers were more common in diabetic patients (13/74 vs 5/79, P less than 0.05). It is concluded that diabetes in the elderly, unlike in young patients, increases the risk of foot problems only marginally.

Ferrous iron transport in Streptococcus mutans.

Radioiron uptake from 59FeCl3 by Streptococcus mutans OMZ176 was increased by anaerobiosis, sodium ascorbate, and phenazine methosulfate (PMS), although there was a 10-min lag before PMS stimulation was evident. The reductant ascorbate may have provided ferrous iron. The PMS was reduced by the cells, and the reduced PMS then may have generated ferrous iron for transport; reduced PMS also may have depleted dissolved oxygen. We conclude that S. mutans transports only ferrous iron, utilizing reductants furnished by glucose metabolism to reduce iron prior to its uptake.

Oxygen toxicity in Streptococcus mutans: manganese, iron, and superoxide dismutase.

When cultured anaerobically in a chemically defined medium that was treated with Chelex-100 to lower its trace metal content, Streptococcus mutans OMZ176 had no apparent requirement for manganese or iron. Manganese or iron was necessary for aerobic cultivation in deep static cultures. During continuous aerobic cultivation in a stirred chemostat, iron did not support the growth rate achieved with manganese. Since the dissolved oxygen level in the chemostat cultures was higher than the final level in the static cultures, manganese may be required for growth at elevated oxygen levels. In medium supplemented with manganese, cells grown anaerobically contained a low level of superoxide dismutase (SOD) activity; aerobic cultivation increased SOD activity at least threefold. In iron-supplemented medium, cells grown anaerobically also had low SOD activity; aerobic incubation resulted in little increase in SOD activity. Polyacrylamide gel electrophoresis of the cell extracts revealed a major band and a minor band of SOD activity in the cells grown with manganese; however, cells grown with iron contained a single band of SOD activity with an Rf value similar to that of the major band found in cells grown with manganese. None of the SOD activity bands were abolished by the inclusion of 2 mM hydrogen peroxide in the SOD activity strain. S. mutans may not produce a separate iron-containing SOD but may insert either iron or manganese into an apo-SOD protein. Alternatively, iron may function in another activity (not SOD) that augments the defense against oxygen toxicity at low SOD levels.

Occupational asthma from nickel sensitivity: I. Human serum albumin in the antigenic determinant.

Occupational asthma from nickel sensitivity was confirmed in a male worker (SB) by allergy skin tests and inhalational challenge. In an ammonium sulphate coprecipitation test 63Ni was selectively precipitated from SB plasma indicating antibody with nickel related specificity. Preincubation of 63Ni with human serum albumin (HSA) increased the specificity of the coprecipitation test. Blocking experiments with nickel and copper(II) salts effectively inhibited the binding of 63Ni to antibody of SB plasma but did not affect control tests or that for antibodies to an unrelated antigen, ampicillin. Co2+ slightly inhibited the binding of 63Ni, while Zn2+ and Mn2+ failed to inhibit. This deactivation pattern corresponds to the known sequence of binding of these metals to the primary copper binding site of HSA. It is concluded that the antigenic determinant depends on the combination of Ni2+ with HSA at this specific copper/nickel plasma transport site.

Occupational asthma from nickel sensitivity: II. Factors influencing the interaction of Ni2+, HSA, and serum antibodies with nickel related specificity.

Serum from an individual with occupational asthma from nickel sulphate inhalation was shown by ammonium sulphate (Farr) and anti-IgG coprecipitation tests to contain antibodies which bind 63Ni2+. This binding was absent from 30 control sera. Ligand competition studies with serum and plasma from the propositus and controls are described, and include serial additions of HSA, L-histidine, EDTA, and the tripeptide gly-gly-L-his. The results, like those from metal ion blocking experiments, clearly showed that the formation of the reactive antigenic determinant depends on the selective binding of Ni2+ at the native Cu2+/Ni2+ transport site of HSA. Corroborating evidence is derived from the similar dependence on pH of the Ni2+-HSA formation and the ammonium sulphate 63Ni2+ coprecipitation reactions.

Cellular binding and/or uptake of nickel(II) ions.

L-Histidine (L-His) and human serum albumin (HSA) at physiological concentrations, like the exogenous ligands D-penicillamine (D-PEN) and EDTA, are shown to inhibit the uptake of physiological levels of Ni2+ by B-lymphoblasts of human origin, human erythrocytes and rabbit alveolar macrophages. Evidence is also presented that illustrates the ability of these ligands to sequester Ni2+ from cells preloaded with this ion. The experimental observations are interpreted to indicate that serum concentrations of HSA and amino acids (especially L-His) exert a controlling influence on the cellular accumulation of Ni2+ in vitro, and further suggest the necessity to standardize the concentrations of these and related constituents in cell-culture media for meaningful comparisons of cellular uptake and toxicity of Ni2+ and other metal ions. Cells were lysed and the fractional distribution of 63Ni2+ in the lysate and residual pellet were assessed. About 60% of the radiolabel occurred in the pellet and 40% in the lysate for B-lymphoblasts, compared to 70 and 30% respectively for the alveolar macrophages. Diethyldithiocarbamate (DDC), unlike the other complexing agents, enhanced the cellular uptake of Ni2+ and prevented its removal from loaded cells. DDC also induced a transfer of the 63Ni2+ from the lysate to the residual pellet, suggesting that it promotes the deposition of Ni2+ in the lipid-rich components of cells (tissues). It is concluded that cellular association of Ni2+ is favoured by ligands forming lipophilic complexes, and extracellular localization by those giving hydrophilic complex compounds. The relevance of these contrasting roles in nickel detoxification by endogenous ligands and chelating drugs is discussed.

Midtrimester intrauterine exchange transfusion of the fetus.

Thirty-seven fetuses, 15 to 23 weeks' gestation, were subjected to intrauterine exchange transfusion under direct vision with a fetoscope prior to therapeutic abortion. A maximum of 30 ml of blood was exchanged, so that as much as 95% of the blood in the fetoplacental circulation was of donor origin. The technique clearly has potential value in the management of severe rhesus-hemolytic disease of newborn infants.

Cyclic vomit in children: seen through the psychiatrist's eye.

Sixteen patients have been seen since 1956 at the Children's Hospital of Pittsburgh with a disgnosis of cyclic vomiting. Five of these patients were reverred for psychiatric consultation or treatment. Four of the 16 had laparotomies and no specific pathological condition was found; seven of the patients did not have surgery or psychiatric intervention. Descriptive follow-up is given for all patients, as well as various methods of handling the problem. The psychological conflicts were found to be parental anxiety, a prolonged symbiotic relationship with the mother, and the failure of the child to separate and individuate.