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Biomedical subjects

R E Haas

Publications and source records attributed to R E Haas.

At least 19 recordsLinked to original sources
PubMed1999

Inosine(15.1) hammerhead ribozymes for targeting the transthyretin-30 mutation.

The most common cause of hereditary amyloidosis (HA) is the val30met mutation in the transthyretin protein (TTR-met30). The mutation is caused by a mononucleic substitution from G to A (GUC to AUC) in the transthyretin gene resulting in the exchange for the amino acids valine to methionine in the corresponding protein sequence. The aim of our work was the development of a specific cleavage of TTR-30 mRNA using hammerhead ribozymes. We chemically modified nuclease stable hammerhead ribozymes to target the TTR-30 mRNA with high specificity. The exchange of adenosine(15.1) with inosine(15.1) in the catalytic core of the hammerhead ribozyme resulted in a change of the cleavable target sequence from N(16.2)U(16.1)H(17) to N(16. 2)C(16.1)H(17) without loss in ribozymal activity (Nucleic Acids Res. 26, 2279-2285, 1998). This modification allowed a specific cleavage of the TTR-30 mutation ("gCC Gug" to "gCC Aug"). In vitro experiments with TTR-30 mRNA demonstrated that the RNase stable inosine(15.1) hammerhead ribozyme cleaved the TTR-30 mRNA with 100% specificity and with a velocity of 0.23 min(-1), whereas no cleavage occured in the wildtype mRNA of TTR. In conclusion, the development of this NCH specific hammerhead ribozyme represents a promising tool for future in vivo therapeutic application for TTR-met30 induced hereditary amyloidosis.

Hydrolysis↗
PubMed1999

The expert witness: defending the profession or prosecuting your peers.

The use of CRNAs as expert witnesses in court cases is well-established. The CRNA who acts as a legal consultant or an expert witness is not retained merely to pontificate in the courtroom based on their considerable experience and expertise. The CRNA will undertake many roles in the process of assisting the attorney including those of (1) record reviewer and data analyst, (2) researcher and retriever, (3) synthesizer, and (4) teacher. Beyond these roles is the philosophical premise that the person best suited to evaluate the competence of a nurse anesthetist is another nurse anesthetist. Poor practitioners who are a danger to the public ought to be held accountable for their failings, whereas excellent practitioners who are mistakenly accused of negligence ought to be defended. Although challenging and time consuming, the role of the legal consultant and expert witness is rewarding in both financial and personal satisfaction terms. The role and functions of the CRNA who takes on the challenges of appearing as an expert witness or legal consultant is explored. The fine points of medical malpractice is not discussed, except as a cursory overview. The goal is to provide the practicing CRNA with the basic tools needed for these roles.

Certification↗
PubMed1998

Learning during anesthesia: myth or reality?

Learning occurs in both explicit and implicit manners. The core purpose of all learning, whether implicit or explicit, is the changing of ideas, behaviors, and/or values. Of major concern to perianesthesia nurses is the safety and comfort of the anesthetized patient. Many patients express the concern that they will hear or, worse still, feel part of their surgery while it is being performed. Patients have learned, explicitly and anecdotally, that such things may occur. This fear is not unfounded, as there have been many reports written describing the phenomenon of intraoperative recall, as well as its prevention and treatment. The concept of implicit learning during anesthesia, however, is much less well known. The primary foci of this article are to evaluate the veracity of the existence of implicit learning, review the techniques by which it is measured, and examine behaviors and/or techniques which enhance (strengthen stimuli) or retard it (suppress stimuli).

Anesthesia↗
PubMed1998

Malignant hyperthermia: a potentially fatal complication of anesthesia.

Malignant hyperthermia (MH) is an uncommon cause of anesthetic-induced death; it is an inherited disorder that is triggered by the administration of anesthetic drugs. MH is triggered by the administration of volatile anesthetic agents and succinylcholine, a depolarizing muscle relaxant. It is imperative that the perianesthesia staff be familiar with the pharmacokinetics and pharmacodynamic properties of dantrolene, which is the only known agent effective in the treatment and prophylaxis of MH.

Anesthesia, General↗
PubMed1998

Using the human patient simulator to test the efficacy of an experimental emergency percutaneous transtracheal airway.

As clinicians continue to gain experience with the use of emergency cricothyrotomy, a need exists to continue to explore methods to perfect both the technique and the equipment used. The clinician in the austere military environment may be forced to be innovative in the design of such a device. A combination of commonly used disposable intravenous equipment for emergency cricothyrotomy is described. Its efficacy for the maintenance of oxygen saturation, arterial oxygen levels, and arterial carbon dioxide levels was determined using the Human Patient Simulator from Medical Education Technologies, Inc. The emergency airway device was compared with the needle cricothyrotomy technique. The control profile for the return of acceptable oxygen saturation and arterial oxygen levels was more closely matched by the emergency airway device than by the needle cricothyrotomy technique.

Cricoid Cartilage↗
PubMed1998

Alpha 2-agonist agents: a review for CRNAs.

Over 300 clonidine-related research articles have been prominently featured in anesthesia journals over the last 4 to 5 years. Nurse anesthetists may already find themselves administering alpha 2-adrenergic agents to help control hypertension; however, in the future their use as anesthetic adjuncts to control pain may also become important. This article reviews the alpha 2-adrenergic (A2) receptor and one of its agonist agents, clonidine.

Adjuvants, Anesthesia↗
PubMed1998

Nitric oxide: a primer for the practicing anesthetist.

Nitric oxide (NO) is receiving interest because of its use in patients with acute respiratory distress syndrome. Because more studies are being conducted, researchers are discovering a vast array of physiological effects attributable to NO. NO has been implicated as having a role in the endogenous regulation of blood pressure; smooth, skeletal, and cardiac muscle relaxation; renal and immune system functioning; and selective pulmonary vasodilation. This article looks at the pharmacological and physiological effects of NO and its current use in the clinical setting.

Adult↗
PubMed1997

In vivo kinetics as a sensitive method for testing physiologically intact human recombinant apolipoprotein A-I: comparison of three different expression systems.

In order to assess the structural and functional integrity of recombinant human apoA-I, we expressed apoA-I using three different expression systems: Baculovirus transfected Spodoptera frugiperda (Sf9) cells, stably transfected Chinese hamster ovary (CHO) cells, and transformed Escherichia coli (E. coli). Purified apoA-I from the three expression systems was radioiodinated and their catabolism was compared in normolipemic rabbits. The kinetic turnover studies of radiolabelled apoA-I in normolipemic rabbits revealed that highly purified recombinant apoA-I had an identical decay curve compared to native apoA-I, regardless whether it was purified from Sf9 cells, CHO cells, or E. coli. We also determined the association of the three recombinant apoA-I forms with both rabbit and human HDL. All three recombinant apoA-I forms were associated with HDL2 and HDL3 after injection into the rabbits and after incubation with human serum using both a Superose 6 column separation system and density gradient ultracentrifugation. The addition of the pro-segment or the addition of methionine at the amino-terminal end of apoA-I did not alter its metabolism and association to HDL. In conclusion, all studied expression systems are capable of producing high levels of physiologically intact recombinant human apoA-I. The aminoterminal addition of the prosegment of apoA-I or methionine did not alter the in vivo metabolism of apoA-I or its association to HDL.

Animals↗
PubMed1997

Comparative recovery from three nondepolarizing neuromuscular blockers in a patient before and after chronic anticonvulsant therapy: a case report.

We describe a 51-year-old patient undergoing a second neurosurgical procedure after being prescribed anticonvulsant therapy. The patient had significant changes in the duration of action of identical doses of nondepolarizing muscle relaxants and we were able to compare the duration of action of neuromuscular blockers before and after the chronic administration of anticonvulsant therapy. A brief review of the possible mechanisms of action of the acceleration of the patient's recovery profile is also presented.

Anticonvulsants↗
PubMed1996

Ions and IVs: are we still using the Henry Ford model?

Intravenous fluid therapy matched to fluid losses provides the patient with appropriate and cost-effective care. While the physiognomies of many of our patients are robust enough to handle nearly any type of intravenous perioperative replacement, we shall all see patients with varying fluid and electrolyte disturbances. Using the tables and formulae in this article will assist the anesthesia provider in tailoring fluids to both tonicity and electrolyte needs.

Body Fluids↗
PubMed1993

Contribution of radiotherapy to the management of malignant melanoma. A ten year experience at the University of Illinois Hospital in Chicago.

Fraction size in radiotherapy of malignant melanoma remains a point of controversy. Among 139 patients treated at the University of Illinois Hospital in 1979-1988, 36 were considered potentially curable (not counting ocular melanomas); 20 were treated by the Princess Margaret Hospital (PMH) hypofractionated schedule using 800 cGy per fraction and achieved a permanency of local control lasting > 6 months since the beginning of radiotherapy in 10/22 (45.5%) courses. Comparable results were obtained in 11 patients treated by standard fractionation to at least threshold curative levels. A modification of PMH regimen in 5 patients (but with 13 courses) by decreasing fraction size to 400 cGy while keeping total dose and course duration unchanged, resulted in a 100% loss of focal control within 6 months. Patients considered incurable and irradiated by PMH schedule responded in 83% of courses compared to 51.4% response rate in patients irradiated with other schedules (except modified PMH regimen). Other aspects of melanoma management are analyzed.

Adolescent↗
PubMed1983

Patterns of cancer recurrence in the postoperatively irradiated neck.

Data from 92 patients with stage III or IV squamous cell carcinoma of the head and neck treated with surgery and planned postoperative radiotherapy were analyzed to determine the incidence and patterns of tumor recurrence. Overall, recurrent tumor in the cervical region developed in 19 patients (21%). Of these, eight were in the neck alone and 11 in both the neck and the primary site. All recurrences were in the ipsilateral cervical region and none in the contralateral neck. The presence of two or more metastatic nodes at the time of surgery correlated with tumor recurrence and decreased survival. Extracapsular tumor spread increased the recurrence rate. Our data suggest that postoperative radiotherapy decreases ipsilateral cervical tumor recurrence in only those patients with more than two metastatic lymph nodes, and contralateral neck recurrence in all patients.

Carcinoma, Squamous Cell↗
PubMed1983

Postoperative radiotherapy for persistent tumor at the surgical margin in head and neck cancers.

Seventy-two patients with a carcinoma of the head and neck, who were treated with surgery and postoperative irradiation, were reviewed to determine the local recurrence rates and survival in patients with inadequate surgical margins. Tumor recurrence rate was 31% for patients with microscopic tumors at resection margins and 50% for those with macroscopic tumor. Actuarial 3-year survival for these patients was 71% and 43%, respectively. All 4 patients who were irradiated later than 6 weeks after surgery developed recurrent malignancy despite the resection margins being free of tumor. Excluding these patients the 3-year survival for R0 patients was similar to that of R1 patients. It is concluded that postoperative irradiation is effective in patients with tumor at the surgical margins. It is suggested that the time interval between surgery and radiation therapy be limited to less than 6 weeks. Radiation dose prescriptions for various clinical situations are discussed.

Carcinoma, Squamous Cell↗