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Biomedical subjects

J W Kwan

Publications and source records attributed to J W Kwan.

6 recordsLinked to original sources
PubMed1996

Nonuniform distribution of cell proliferation in the adult teleost retina.

Teleost fish continue to grow throughout life, and their eyes enlarge correspondingly. Within the eye, the retina grows by stretching existing tissue and adding new cells. Cell addition occurs in two ways: First, all cell types except rod photoreceptors are added circumferentially at the edge of the eye where the retina meets the iris; second, rod photoreceptors are generated from a population of rod progenitor cells which divide throughout the outer nuclear layer (ONL). To determine the spatial distribution of rod progenitor cells across the teleost retina, we labeled dividing cells with an antibody to proliferating cell nuclear antigen (PCNA) throughout a 24 h period. We found a significantly higher density of dividing rod precursor cells at the nasal and temporal margins than in the central retina throughout the 24 h cycle. At night, the density of dividing cells is significantly greater at the nasal pole of the eye. The difference between cell division at the center and the margin was reduced at night when the density of cell division in the central retina increased significantly. Taken together, these data suggest that the eye grows asymmetrically, with more cells added at the nasal pole. Possible developmental causes and functional consequences of the reported distribution of cell divisions in time and location are presented.

Analysis of Variance↗
PubMed1991

High-technology i.v. infusion devices.

Some of the newer high-technology infusion devices commercially available or under development are described. The range of infusion devices includes both controllers and pumps; pumps can be classified by mechanism of operation (peristaltic, syringe, cassette, elastomeric reservoir), frequency or type of drug delivery (continuous or intermittent infusion, bolus dosing, single- or multiple-solution delivery), or therapeutic application (such as the patient-controlled analgesia, or PCA, pump). Advances in infusion technology and computer technology have led to the development of devices with extremely sophisticated drug-delivery capabilities (multiple-rate or multiple-solution programming, operation as pump or controller, or both, and interchangeable applications and settings). Current research in infusion-device technology is focusing on implantable pumps, pumps with chronobiological applications, osmotic-pressure devices, and open- and closed-loop systems. Pharmacists need to keep abreast of the rapidly changing intravenous device marketplace to provide clinical expertise and leadership in the review and evaluation of high-technology drug delivery systems.

Analgesia, Patient-Controlled↗
PubMed1991

Pharmacists' knowledge of infusion devices.

Results of a mail survey of pharmacists' knowledge of infusion-device technology are presented. In order to develop recommendations on how to prepare pharmacists to take responsible roles in the use of infusion devices, a survey was mailed to 576 directors of pharmacy in hospitals and home health-care companies, deans of pharmacy schools, and executives of state pharmaceutical associations. A total of 237 responses (41.2%) was received. Directors in both hospital and home health-care settings predicted increases in the use of infusion devices in their respective settings within the coming five years. Practitioners and deans concurred that pharmacy schools are not providing adequate instruction in the use of these devices. All four groups of respondents believed that the competencies most essential in the use of these devices are knowledge of therapeutic applications and the ability to select the most appropriate pump to meet clinical needs. Use of drug-infusion technology will increase in the coming five years, and undergraduate, postgraduate, and inservice pharmacy curricula must prepare pharmacists to use it appropriately.

Home Care Services↗
PubMed1990

Use of infusion devices for epidural or intrathecal administration of spinal opioids.

The use of infusion devices for epidural or intrathecal administration of spinal opioids is described. The risks of infection and mechanical catheter complications, the need for escalating doses, reservoir volume, drug stability, and cost are practical considerations associated with use of both external and internal infusion systems. Use of patient criteria to identify suitable candidates for intraspinal administration of pain medication helps ensure successful management. The criteria for intraspinal delivery pumps are safety, accuracy, reliability, ease of management by the patient and the health-care professional, and compatibility of the drug with the pump components. The primary factors to consider when comparing pumps to be used for intraspinal delivery of pain medication are the volume and flow rate requirements of the devices. External portable infusion devices are classified according to the mechanism of operation into three primary groups: syringe pumps, peristaltic mechanisms, and elastomeric reservoir pumps. Portable patient-controlled analgesia pumps that have syringes, flexible reservoir bags, and elastomeric reservoirs have been developed. Implanted systems with flow rates that are preset at the factory make pain management more difficult when the patient requires changes or escalations in doses over time. A programmable implanted pump is available. Two advantages of continuous epidural or intrathecal infusion are (1) the peaks and valleys of pain relief with bolus injections are eliminated and (2) the need for multiple injections is reduced. Patient-controlled analgesia (PCA) pumps enhance the efficacy of continuous infusions by allowing the patient to administer bolus doses to control acute pain.

Humans↗
PubMed1989

High-technology i.v. infusion devices.

Some of the newer high-technology infusion devices commercially available or under development are described. The range of infusion devices includes both controllers and pumps; pumps can be classified by mechanism of operation (peristaltic, syringe, cassette, elastomeric reservoir), frequency or type of drug delivery (continuous or intermittent infusion, bolus dosing, single- or multiple-solution delivery), or therapeutic application (such as the patient-controlled analgesia, or PCA, pump). Advances in infusion technology and computer technology have led to the development of devices with extremely sophisticated drug-delivery capabilities (multiple-rate or multiple-solution programming, operation as pump or controller, or both, and interchangeable applications and settings). Current research in infusion-device technology is focusing on implantable pumps, pumps with chronobiological applications, osmotic-pressure devices, and open- and closed-loop systems. Pharmacists need to keep abreast of the rapidly changing intravenous device marketplace to provide clinical expertise and leadership in the review and evaluation of high-technology drug delivery systems.

Ambulatory Care↗