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Biomedical subjects

W Robbins

Publications and source records attributed to W Robbins.

11 recordsLinked to original sources
PubMed2005

Passive wireless MEMS microphones for biomedical applications.

This paper introduces passive wireless telemetry based operation for high frequency acoustic sensors. The focus is on the development, fabrication, and evaluation of wireless, battery-less SAW-IDT MEMS microphones for biomedical applications. Due to the absence of batteries, the developed sensors are small and as a result of the batch manufacturing strategy are inexpensive which enables their utilization as disposable sensors. A pulse modulated surface acoustic wave interdigital transducer (SAW-IDT) based sensing strategy has been formulated. The sensing strategy relies on detecting the ac component of the acoustic pressure signal only and does not require calibration. The proposed sensing strategy has been successfully implemented on an in-house fabricated SAW-IDT sensor and a variable capacitor which mimics the impedance change of a capacitive microphone. Wireless telemetry distances of up to 5 centimeters have been achieved. A silicon MEMS microphone which will be used with the SAW-IDT device is being microfabricated and tested. The complete passive wireless sensor package will include the MEMS microphone wire-bonded on the SAW substrate and interrogated through an on-board antenna. This work on acoustic sensors breaks new ground by introducing high frequency (i.e., audio frequencies) sensor measurement utilizing SAW-IDT sensors. The developed sensors can be used for wireless monitoring of body sounds in a number of different applications, including monitoring breathing sounds in apnea patients, monitoring chest sounds after cardiac surgery, and for feedback sensing in compression (HFCC) vests used for respiratory ventilation. Another promising application is monitoring chest sounds in neonatal care units where the miniature sensors will minimize discomfort for the newborns.

Acoustics↗
PubMed2000

Protective effect of pregnancy in women with lithium-responsive bipolar disorder.

BACKGROUND: Recent psychiatric literature, while indicating a high incidence of postpartum depression, contains a few clinical reports which support our observations that women with episodic bipolar disorder often remain well without treatment during pregnancy. Our retrospective study statistically examines the clinical course of 28 women with RDC typical bipolar disorder, type I, who became pregnant prior to receiving successful lithium prophylaxis. METHODS: We derived all data from the International Group for the Study of Lithium-treated Patients (IGSLI) database of excellent lithium responders. Data were compared both intraindividually, using data from three 9-month periods - immediately prior to pregnancy, pregnancy and postpartum - and interindividually, using never-pregnant women as controls. RESULTS: Intraindividual data show that women with typical bipolar disorder, type I, experience significantly fewer and shorter recurrences during pregnancy than either before or after. Interindividual comparisons indicate that the recurrence risk during pregnancy is markedly lower than the clinical course would predict. Moreover, the few recurrences observed during pregnancy all took place in the last 5 weeks. LIMITATIONS: Limiting cases to lithium responsive patients could have reduced heterogeneity and perhaps generalizability. CONCLUSIONS: The findings, nonetheless, indicate a marked improvement of the clinical course of typical bipolar disorder, type I, lithium-responsive, during pregnancy. Exploring the underlying protective mechanisms may lead to new understanding of the pathophysiology of mood disorders and to new approaches to treatment and prevention.

Adult↗
PubMed2000

Clinical applications of capsaicinoids.

Capsaicinoids are molecules derived from chili peppers. They are best known for their pungency, producing mild to intense spice upon ingestion. It has long been known that peppers possess unusual qualities. Historically, they were burned in war rituals, and used to stimulate appetite. In 1997, a gene that encoded for a receptor specific for capsaicinoids was identified. Called VR1, this fatty acid receptor is present only on C fibers, and when activated produces desensitization or degeneration of the sensory afferent. Today, capsaicinoids are being studied as effective treatments for a number of sensory nerve fiber disorders, including pain associated with arthritis, cystitis, human immunodeficiency virus, and diabetic neuropathy.

Capsaicin↗
PubMed1995

Prevention of bronchoconstriction by an orally active local anesthetic.

Stimulation of airway irritant receptors produces reflex bronchoconstriction that can be prevented by pretreatment with anticholinergic drugs or local anesthetics delivered by aerosol or intravenously. We compared therapeutic doses of an orally administered local anesthetic, mexiletine hydrochloride, and intravenously administered lidocaine at blocking histamine-induced bronchoconstriction in five basenji-greyhound dogs, using high-resolution computed tomography (HRCT) to directly measure changes in airway size. In the dogs given placebo, a histamine infusion decreased airway area to 61 +/- 2% (mean +/- SEM) of control (p < 0.01). Mexiletine pretreatment completely prevented histamine-induced airway constriction, with an airway area that was 94 +/- 4% of the control value during the histamine infusion (p = 0.07 compared with baseline). Mexiletine serum levels were therapeutic (1.7 +/- 0.3 mg/L). Similarly, pretreatment with lidocaine significantly blunted the airway constriction provoked by intravenous histamine. In lidocaine-pretreated dogs, histamine decreased airway area to 79 +/- 4% of baseline (p < 0.01). As in the case of mexiletine, lidocaine serum levels were also therapeutic (2.4 +/- 0.3 mg/L). Mexiletine was more effective than lidocaine at preventing histamine-induced bronchoconstriction (p = 0.02). These data suggest that orally administered local anesthetics may be useful in preventing irritant-induced bronchoconstriction in humans.

Animals↗
PubMed1990

Recombinant human erythropoietin for patients with AIDS treated with zidovudine.

Bone marrow suppression and anemia are frequent side effects of treatment of the acquired immunodeficiency syndrome (AIDS) with zidovudine (formerly azidothymidine [AZT]). We conducted a randomized, double-blind, placebo-controlled clinical trial of recombinant human erythropoietin (100 U per kilogram of body weight thrice weekly by intravenous bolus) in 63 patients with AIDS treated with zidovudine (29 in the erythropoietin group and 34 in the placebo group). Reductions in the number of units of red cells transfused and the number of patients given transfusions per month became apparent in the second and third months of the trial. The reductions were observed in patients with endogenous erythropoietin levels less than or equal to 500 IU per liter at base line, but not in patients whose levels were greater than 500 IU per liter at the beginning of the study. Although the hematocrit and hemoglobin level were not used as the primary criteria of efficacy because the patients received transfusions when their physicians decided that they needed them, a significantly higher rate of increase in the hematocrit was observed in the patients treated with recombinant human erythropoietin whose levels of endogenous erythropoietin were less than or equal to 500 IU per liter (0.00353 points per week) than in the patients given placebo (0.00116 points per week). This effect was not seen in patients with higher levels of endogenous erythropoietin. Serious side effects did not occur more often in the group treated with erythropoietin than in the placebo group. We conclude that recombinant human erythropoietin may be useful in patients with AIDS treated with zidovudine, although the indicators for its use remain to be clarified.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Nocardia asteroides osteomyelitis.

Nocardia asteroides osteomyelitis has previously been described only in acutely ill patients. It may occur as an isolated event or part of the disease spectrum of disseminated nocardiosis. An 84 year old immune competent man with N. asteroides right tibial osteomyelitis had an unusual presentation, presumed mechanism of disease and outcome. His course affords an opportunity to review the literature on N. asteroides osteomyelitis and to discuss the unique features of his case.

Aged↗
PubMed1985

Recurrent Salmonella typhimurium bacteremia associated with the acquired immunodeficiency syndrome.

Seven Haitian and one white patient with the acquired immunodeficiency syndrome and Salmonella typhimurium bacteremia were identified over a 28-month period. In three patients bacteremia developed concurrently with an opportunistic infection associated with the acquired immunodeficiency syndrome. The remaining five patients had their initial episodes of bacteremia 3 to 11 months before the diagnosis of the acquired immunodeficiency syndrome. These five patients had signs suggestive of the syndrome, plus evidence of disordered cellular immune function (lymphopenia, anergy, decreased T-helper cells, decreased proliferative responses, and a deficiency in mononuclear-cell alpha interferon production). Salmonella typhimurium bacteremia in the appropriate clinical setting may be an opportunistic pathogen associated with the acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1981

Oral Hygiene Skill Achievement Index II.

The utility of any index depends on its validity, reliability, and administrative feasibility. The Oral Hygiene Skill Achievement Index (S.A.I.) was found to be a valid measure of oral hygiene skill in that registered dental hygienists received greater than 90% of the total possible points. The S.A.I. was found to have an initial reliability of r greater than or equal to 0.91 and a repeat reliability of r greater than or equal to 0.96. The S.A.I. requires less than 10 minutes to administer, 40 minutes to teach, and 1 hour and 40 minutes to learn. The results suggest that S.A.I. should be a useful instrument for both clinical and research use.

Achievement↗