Benjamin R. Fisher

Latex-associated allergies and anaphylactic reactions

The recent reports of severe anaphylactic reactions and several fatalities caused by contact with latex-containing products raised concerns in the medical community. Although hypersensitivity to natural rubber has been widely reported in the literature, the prevalence and severity of reactions have rapidly increased in the last few years. Latex proteins, constituents of natural latex, appear to be responsible for the sensitization. Many investigators, including our laboratory, are focused on the identification of proteins in raw latex and latex products, specifically those responsible for the elicitation of allergic responses. This paper summarizes available information on the mechanism and epidemiology of latex sensitivity and reviews research efforts toward the identification of the antigen(s) responsible for the reactions. The questions of proper diagnosis and testing, heightening awareness, and prevention of reactions are also addressed.

Relationship between stress protein induction in rat kidney by mercuric chloride and nephrotoxicity

Adverse environmental stimuli increase the synthesis of a class of proteins referred to as stress proteins. The effect of mercuric chloride, a model nephrotoxin, on protein synthesis in male rat kidney has been evaluated. Renal slices from exposed rats were incubated with [35S]methionine for 1 hr and subjected to SDS-PAGE, after which 35S-labeled proteins were detected by autoradiography. Enhanced de novo synthesis of 70- and 90-kDa relative molecular mass (M(r)) proteins were detected 2 hr after exposure to 1 mg Hg/kg, with maximum activity occurring at 4-8 hr. By 16 hr postinjection, synthesis of these two proteins had decreased. Dose-related increases in synthesis of these proteins, and of a 110-kDa protein, were observed 4 hr after i.v. injection of 0.25, 0.5, and 1.0 mg Hg/kg, with concomitant inhibition of synthesis of proteins of M(r) 38 and 68 kDa. At a dose of 1 mg/kg, kidney proximal tubules exhibited progressive degenerative changes from 4 to 24 hr. A functional deficit, decreased uptake of [para-3H]aminohippurate into renal slices, was not observed until 16 hr after i.v. injection of 1 mg/kg. No significant histopathologic changes were observed in kidneys 4 hr after treatment with 0.25 or 0.5 mg Hg/kg, iv. No changes in liver protein synthesis were apparent until 16-24 hr, where an increase in the 70- and 90-kDa proteins was observed. A concomitant increase in plasma sorbitol dehydrogenase activity occurred at 16-24 hr; however, there was no histopathological evidence of liver injury. The 72-kDa inducible member of the 70-kDa stress protein family and the 88-kDa member of the 90-kDa protein family were detected by immunoblotting techniques using monoclonal antibodies. The data demonstrate that Hg induces alterations in the expression of renal gene products in vivo as evidenced by enhanced stress protein synthesis and inhibition of synthesis of constitutive proteins. These changes in renal protein synthesis preceded overt renal injury, occurring in the early stages of nephropathy. Altered patterns of stress protein synthesis appeared to be target organ specific. The data suggest that altered protein synthesis patterns may serve as biomarkers of renal injury.

Stress protein synthesis induced by cadmium-cysteine in rat kidney☆

Biomarkers are important tools which enable toxicologists to reliably predict and detect exposures to xenobiotics and resultant cell injury, ultimately improving risk assessments. Since the de novo synthesis of stress proteins can be detected early after exposure to some agents, analysis of toxicant-induced changes in gene expression, i.e. alterations in patterns of protein synthesis, may be useful to develop as biomarkers of exposure and toxicity. We are utilizing various xenobiotics as tools to study stress protein synthesis in target organs in order to evaluate the target tissue-specificity of this response. Previous data from this laboratory have demonstrated that induction of stress proteins in rat liver, but not kidney, after acute exposure to CdCl2 precedes hepatoxicity. Since kidney is a target tissue after chronic Cd exposure, it was of interest to examine stress protein synthesis in this tissue. However, dose-limiting hepatotoxicity precluded this evaluation. Cd complexed with molecules such as cysteine (cys) or metallothionein has been used in acute dosing regimens as a tool in order to study the nephrotoxicity of Cd. Therefore, this study was undertaken in order to evaluate Cd-induced stress protein synthesis in an important tissue known to be injured after chronic exposure, i.e. kidney. Specific objectives included comparing stress protein synthesis in rat kidney and liver after acute exposure to Cd-cys and CdCl2, determining the Cd threshold concentration for renal stress protein synthesis and assessing the relationship between stress protein synthesis and nephropathy. Male rats were exposed to equivalent doses of Cd as CdCl2 or Cd-cysteine (molar ratio Cd:cys = 1:15). Kidney Cd concentrations increased 5-fold after i.v. injection of Cd-cys compared to CdCl2, mimicking Cd distribution following chronic exposure. After exposure to Cd, tissue slices were incubated with 35S-methionine. Slices were subsequently homogenized and centrifuged, and the 16,000 g supernatants were subjected to SDS-polyacrylamide gel electrophoresis. Proteins which had incorporated 35S-methionine were detected by autoradiography. De novo synthesis of 70, 90 and 110 kDa proteins was enhanced in liver, but not in kidney, 4 h after injection of 2 mg Cd/kg as CdCl2. In contrast, dose-related increases in synthesis of these proteins were observed in kidney 4 h after injection of 1 and 2mg Cd/kg as Cd-cys, but not at lower dosages. In addition, synthesis of a 68 kDa kidney protein was inhibited at 2 mg Cd/kg as Cd-cys. The threshold for Cd-induced stress protein synthesis was shown to be between 4 and 8 micrograms Cd/g tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Heat‐induced alterations in embryonic cytoskeletal and stress proteins precede somite malformations in rat embryos

Previous work from this laboratory has demonstrated that heat exposure on gestation day 10 (GD10) resulted in disrupted somite development 24 hr after exposure and subsequent thoracic skeletal malformations in neonates. The purpose of the present study was to examine the effects of in vitro heat shock on de novo protein synthesis and on cytoskeletal protein levels in developing rat embryos. Explanted GD10 embryos were exposed to temperatures of 42-42.5 degrees C for 15 min. At various times postexposure (0-27 hr). embryos were labeled with 35S-methionine and processed for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation. Transient enhanced de novo synthesis of 70- and 90-kD proteins was observed 1-8 hr after exposure. The 70-kD protein was identified as a eukaryotic stress protein and the presence of this protein was detected between 2 and 27 hr posttreatment. Western blot analysis was used to detect quantitative changes in total actin (microfilaments), tubulin (microtubules), and vimentin (intermediate filaments). Immediately following exposure, a reduction of total vimentin to minimal detectable levels was observed in heat-treated embryos. Levels of total vimentin remained depressed for more than 2 hr and gradually returned to control levels 4-8 hr postexposure. No change in total actin or tubulin was detected in treated embryos. The data demonstrate that heat-induced alterations in proteins comprising intermediate filaments occur concomitantly with the induction of stress proteins and precede aberrant somite morphology. These alterations in embryonic proteins may help elucidate the mechanism(s) by which skeletal malformations are produced.

Variations in latex protein profiles

Abstract Delayed hypersensitivity to natural latex is well documented, but there is an increasing number of reports of severe allergic reactions associated with exposure to latex products. Recent studies indicate that latex anaphylaxis is mediated by water soluble proteins in latex, but the specific antigen(s) responsible for the sensitization has not been definitively identified. Differences in the type and severity of the allergic reaction may be due to differences in an individuals sensitivity or variations in the constituent proteins found in latex. The purpose of this study was to assess the qualitative differences between the proteins present in a variety of latex sources. Proteins extracted from fresh and ammoniated latex and various latex products were separated by SDS-PAGE. Our results indicate that substantial variation exists in the constituent proteins obtained from various sources of raw latex, various latex products, as well as among the same product from various manufacturers. These qualitative differences in the proteins of various latex preparations may help explain, in part, variations in the reported identification of latex antigens.

Stimulating Patient Engagement in Medical Device Development in Kidney Disease: A Report of a Kidney Health Initiative Workshop

New technologies challenge current dialysis treatment paradigms as devices become smaller, more portable, and increasingly used outside the dialysis clinic. It is unclear how patients will view this care transition, and it will be important to consider patient and care partner perspectives during all aspects of development for novel dialysis therapies, from design and clinical trials to regulatory approval. To gain insight into this area, the Kidney Health Initiative, a public-private partnership between the American Society of Nephrology, the US Food and Drug Administration, and nearly 80 member organizations and companies dedicated to enhancing patient safety and fostering innovation in kidney disease, convened a workshop of patients, care partners, and other kidney community stakeholders. The workshop included background presentations followed by focused small group discussions in 3 areas (device design, clinical trials, and regulatory approval). Participants explored how to involve patients throughout the life cycle of a medical device, including discussions of how patients can influence device design, assist in the planning and implementation of clinical trials, and provide input to affect regulatory decisions. Patients were engaged in the workshop discussion and interested in sharing their perspectives, but they recommended additional efforts around education, communication, and outreach in these areas.

Development of a nationally-representative coordinated registry network for prostate ablation technologies

Purpose: The accumulation of data through a prospective, multicenter coordinated registry network is a practical way to gather real world evidence on the performance of novel prostate ablation technologies. Urological oncologists, targeted biopsy experts, industry representatives and representatives of the FDA (Food and Drug Administration) convened to discuss the role, feasibility and important data elements of a coordinated registry network to assess new and existing prostate ablation technologies. Materials and Methods: A multiround Delphi consensus approach was performed which included the opinion of 15 expert urologists, representatives of the FDA and leadership from high intensity focused ultrasound device manufacturers. Stakeholders provided input in 3 consecutive rounds with conference calls following each round to obtain consensus on remaining items. Participants agreed that these elements initially developed for high intensity focused ultrasound are compatible with other prostate ablation technologies. Coordinated registry network elements were reviewed and supplemented with data elements from the FDA common study metrics. Results: The working group reached consensus on capturing specific patient demographics, treatment details, oncologic outcomes, functional outcomes and complications. Validated health related quality of life questionnaires were selected to capture patient reported outcomes, including the IIEF‐5 (International Index of Erectile Function‐5), the I‐PSS (International Prostate Symptom Score), the EPIC‐26 (Expanded Prostate Cancer Index Composite‐26) and the MSHQ‐EjD (Male Sexual Health Questionnaire for Ejaculatory Dysfunction). Group consensus was to obtain followup multiparametric magnetic resonance imaging and prostate biopsy approximately 12 months after ablation with additional imaging or biopsy performed as clinically indicated. Conclusions: A national prostate ablation coordinated registry network brings forth vital practice pattern and outcomes data for this emerging treatment paradigm in the United States. Our multiple stakeholder consensus identifies critical elements to evaluate new and existing energy modalities and devices.

Stress Proteins as Biomarkers of Toxicity

The development of more sensitive and predictive test methods to characterize the safety of drugs and chemicals is an important part of the missions of the U.S. Food and Drug Administration and the U.S. Environmental Protection Agency. One approach is to develop methodologies which would define biomarkers of exposure and toxicity. Biomarkers have been proposed to be used to: 1) identify potential hazards, 2) establish dose-response relationships, 3) estimate risk at low-dose exposures, 4) serve as short-term in vitro toxicity tests, and 5) improve risk assessment and risk management capabilities (Committee on Biological Markers, 1987).