Current-conveyor-based wide-band current driver for electrical impedance tomography.

OBJECTIVE: In this paper a wide-band integrated current driver for electrical impedance tomography (EIT) is presented. The application is primarily for prostate and breast cancer detection which require the tissue to be interrogated at frequencies up to 10 MHz while achieving low harmonic distortion and high accuracy. APPROACH: The current driver is based on current conveyor architecture and can deliver 1.2 mA of peak to peak ac current between frequencies of 100 Hz-10 MHz. It is fabricated in CMOS 0.18 [Formula: see text]m technology with a power supply of 3.3 V, and occupies a core area of 0.26 [Formula: see text]. MAIN RESULTS: The measured harmonic distortion for a peak current of 1.2 mA is <[Formula: see text] for frequencies less than 100 kHz, and increases to [Formula: see text] at 10 MHz. The measured output impedance of the current driver is 101 k[Formula: see text] at 1 MHz and 19.5 k[Formula: see text] at 10 MHz. SIGNIFICANCE: The circuit is suitable for high frequency active electrode applications.

Corticotropin-releasing hormone (CRH) expression and protein kinase A mediated CRH receptor signalling in an immortalized hypothalamic cell line.

Corticotropin-releasing hormone (CRH) is a 41 amino acid neuropeptide which plays an important role in the stress response in the hypothalamus. We describe the development of an immortalized hypothalamic cell line which expresses CRH. We hypothesized that this cell line would possess the relevant characteristics of parvocellular CRH-expressing neurones such as glucocorticoid receptor (GR) expression and vasopressin (VP) coexpression. For production of hypothalamic cells, embryonic day 19 rat pup hypothalami were dissected and dissociated into tissue culture dishes. They were immortalized by retrovirus-mediated transfer of the SV40 large T antigen gene at 3 days of culture and then screened for expression of CRH following dilution cloning. One cell line was chosen (IVB) which exhibited CRH-like immunoreactivity (CRH-LI) and expressed CRH, VP and CRH1 receptor RNA via the reverse transcriptase-polymerase chain reaction. In addition, the cell line expressed the neuronal marker, microtubule-associated protein-2. We verified that the CRH-LI from IVB cell lysates coeluted with CRH standard via reversed-phase high-performance liquid chromatography (HPLC). Furthermore, oxidation of the lysate converted its HPLC profile to that identical with oxidized CRH standard. In addition, IVB cells exhibited high affinity binding to CRH. Incubation of IVB cells with CRH lead to increases in cAMP levels and protein kinase A activity in a concentration-dependent manner. Incubation of IVB cells with CRH also resulted in increases in phospho-cyclic-AMP response element binding protein (CREB) immunostaining as detected by immunocytochemical analysis. Finally, CRH treatment of IVB cell lines has been linked to CREB-mediated gene expression as determined via the PathDetect CREB trans-reporting system. The characteristics of IVB cells, such as CRH and VP coexpression, GR expression and a biologically active CRH-R1-mediated signalling pathway, suggest that this neuronal cell line may serve as model of parvocellular CRH neurones.

"Captain of the ship" doctrine continues to take on water.

The captain of the ship doctrine, which has been interpreted to mean that the surgeon's mere presence in the OR subjects him or her to legal liability for everyone's negligence in that room (akin to the responsibility of the captain of a ship who is held responsible for everything that happens on that ship), emerged in 1949 and grew in popularity through the 1950s. The major reason for this doctrine's popularity was that injured patients were precluded from suing hospitals under the then applicable charitable immunity doctrine. Charitable immunity declined in the 1960s, and by the 1970s, so too was the captain of the ship doctrine in decline. Pennsylvania, which first used the picturesque phrase in 1949, rejected the doctrine in 1974. In the meantime, it has come under much criticism, even among states that adopted it. Despite this decline and despite court language that sometimes borders on ridicule (e.g., anachronistic, prostrate doctrine, indiscriminate repetition), the felicity of the phrase has kept it alive in some states and in many ORs, even in states that have expressly rejected the doctrine. Even more than 20 years after its first rejection, however, courts still are being asked to adopt the doctrine. In 2001, the Wisconsin Supreme Court declined to adopt the doctrine, adding to the litany of states that have taken an express position against it.

NASPE expert consensus document: use of i.v. (conscious) sedation/analgesia by nonanesthesia personnel in patients undergoing arrhythmia specific diagnostic, therapeutic, and surgical procedures.

Use of IV (Conscious) Sedation/Analgesia by Nonanesthesia Personnel in Patients Undergoing Arrhythmia Specific Diagnostic, Therapeutic, and Surgical Procedures. This article is intended to inform practitioners, payers, and other interested parties of the opinion of the North American Society of Pacing and Electrophysiology (NASPE) concerning evolving areas of clinical practice or technologies or both, that are widely available or are new to the practice community. Expert consensus documents are so designated because the evidence base and experience with the technology or clinical practice are not yet sufficiently well developed, or rigorously controlled trials are not yet available that would support a more definitive statement. This article has been endorsed by the American College of Cardiology, October 1997.

Monitoring i.v. conscious sedation, the legal scope of practice.

Registered nurses who are not CRNAs and are undertaking the administration and/or monitoring of patients receiving IV conscious sedation should consult their state board of nursing, undertake and document the additional education or training to monitor IV conscious sedation patients safety and document the successful achievement of competency in these services, and work with nursing, surgery, and anesthesia staff members to develop written protocols and policies. Written policies must include the provisions, if any, as prescribed by the state's board of nursing. The provisions of other state boards of nursing could be considered for possible inclusion. Policies should reflect nursing practice as described in the professional literature. Professional association position statements, such as those issued by the ANA and endorsed by AORN and other specialty associations and those issued by AANA, should be consulted. AORN's "Recommended practices for monitoring patients receiving intravenous conscious sedation" in the 1993 edition of AORN Standards and Recommended Practices for Perioperative Nursing should be incorporated into the institution policy as appropriate.

Issues regarding parents in the operating room during their children's care.

The presence of parents in the operating room does have possible legal ramifications. Taking an upset child from a parent's arms, however, is not a positive situation either. Perioperative nurses should not automatically weigh legal implications more heavily than the patient benefit that may be derived from the presence of parents. Whether parents should or should not be allowed to accompany their children into the operating room should be a carefully considered institutional policy.

Informed consent: Part II.

Although the legal responsibility to inform and obtain the patient's consent lies with the surgeon, the agency may have a duty to ensure that the patient's consent has been obtained. Agency liability is limited to those cases in which the agency knew (or should have known) that informed consent was not obtained. It is still unclear whether agencies have an affirmative duty to ensure that consent has been obtained. If this duty does exist, it appears that a policy requiring documentation in the medical record of the patient's consent meets this requirement. It is clear that whatever the extent of the agency's duty, it does not include the duty to give the patient information or assess his or her level of understanding. Court opinions discourage anyone but the physician from doing so. A nurse's legal responsibility is limited to following agency policy. Courts have not recognized any independent nurse duty beyond that which accrues to them as employees of the agency. Perioperative nurses often provide the final checkpoint that consent has been obtained and documented before the procedure begins. This unique position raises additional legal concerns if the agency's policy is not followed or if the premedicated patient arrives without proper consent documentation in the record. Perioperative nursing concerns will be discussed next month in Part III.