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Biomedical subjects

L Lewis

Publications and source records attributed to L Lewis.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Dissociative detachment and memory impairment: reversible amnesia or encoding failure?

The authors propose that clinicians endeavor to differentiate between reversible and irreversible memory failures in patients with dissociative symptoms who report "memory gaps" and "lost time." The classic dissociative disorders, such as dissociative amnesia and dissociative identity disorder, entail reversible memory failures associated with encoding experience in altered states. The authors propose another realm of memory failures associated with severe dissociative detachment that may preclude the level of encoding of ongoing experience needed to support durable autobiographical memories. They describe how dissociative detachment may be intertwined with neurobiological factors that impair memory, and they spell out the significance of distinguishing reversible and irreversible memory impairment for diagnosis, patient education, psychotherapy, and research.

Amnesia↗
PubMedDate not supplied

Multi-institutional phase 2 study of TLK286 (TELCYTA, a glutathione S-transferase P1-1 activated glutathione analog prodrug) in patients with platinum and paclitaxel refractory or resistant ovarian cancer.

The purpose of this study was to determine the safety and efficacy of TLK286 (TELCYTA(TM)), a glutathione analog prodrug, in patients with platinum and paclitaxel refractory or resistant ovarian carcinoma. Thirty-six patients with measurable disease were enrolled. TLK286 was administered at 1000 mg/m2 intravenously every 3 weeks. The endpoints were objective response rate assessed by Response Evaluation Criteria in Solid Tumors (RECIST) and survival. Adverse events were graded using the National Cancer Institute Common Toxicity Criteria. Thirty-four platinum refractory or resistant patients (94%) were evaluable for objective tumor response. Five patients (15%) had objective tumor responses, including one durable complete response (CR) of greater than 3 years and continuing. The disease stabilization rate was 50%, including one CR (3%), four partial responses (12%), and 12 durable disease stabilizations (35%). Responses were accompanied by improvement in clinical symptoms and Eastern Cooperative Oncology Group Performance Status (ECOG PS) and decline in CA125 levels. Median survival was 423 days with survival of 60% at 1 year and 40% at 18 months. TLK286 was well tolerated in this population. TLK286 is an active agent in chemotherapy-resistant ovarian cancer. Further studies of TLK286 in platinum and paclitaxel refractory or resistant ovarian cancer are in progress.

Adult↗
PubMedDate not supplied

Micromethod for the assay of renin of seven species.

Renin was extracted and purified from human, dog, hog, rat, beef, rabbit and sheep kidneys. The renin "concentration" of these preparations was determined and expressed in international (Goldblatt) units by measuring the pressor effect produced by intravascular injection into normal dogs of a permanent colony. The renin "activity" was determined by bioassay, in the rat, of the angiotensin produced by incubation in vitro with renin substrate prepared from the serum of nephrectomized dogs. The rate of angiotensin formation was proportional to the concentration of renin, independent of the substrate concentration, and rather similar for renin of all seven species (mean rate = 55 x 10(4) ng angiotensin/unit renin/16 hrs). Due to this uniformity, either of the two international reference preparations of renin (human or hog) from the World Health Organization can serve as an internal standard in the assay of reninof each of the seven species, to express their concentration in terms of the international unit. Renin substrate from hog plasma was suitable for the assay of human, dog and hog renin (mean rate = 55 x 10(4)). However, it reacted much more slowly with the renin of rat, beef, rabbit and sheep (mean rate = 9 x 10(4)) and was, therefore, less suitable for their assay.

Angiotensins↗
PubMedDate not supplied

Anabolic steroid administration during nutritional support: a therapeutic controversy.

Nitrogen balance was determined in 48 patients who were entered into a randomized prospective double-blind study, comparing anabolic steroids versus placebo in our parenteral nutritional support system. The group included both young and old patients suffering from catabolic illnesses, in whom intravenous feeding ranged from 14-21 days. All participants received the active agent or placebo biweekly throughout the study. During the period of intravenous nutrition, there was statistically significant difference in nitrogen balance and protein conservation in the patients receiving the active agent.

Anabolic Agents↗
PubMedDate not supplied

Effect of emulsifier blend on the characteristics of sustained release diclofenac microspheres.

This investigation involved the evaluation of the emulsifier blend effect on the development of sustained release diclofenac microspheres intended for use in a suspension formulation. The microspheres were prepared using the hydrophobic congealable disperse phase method. The emulsifier blend consisted of glycerol, monostearate (GMS), a hydrophobic emulsifier with HLB = 3.8, and Tween 80, a hydrophilic emulsifier with a HLB value of 15. The effect of this blend on the encapsulation efficiency, size distribution and drug release from the microspheres was studied. A critical amount of GMS (> 0.2 g) was found to be necessary for good encapsulation efficiency. X-ray diffractograms revealed that the drug retains its crystalline state within the microspheres, indicating that the drug is present as a dispersion within the wax matrix. Increasing amounts of Tween 80 caused an increase in the drug release while increased amounts of GMS retarded the release. The hydrophilic emulsifier and the emulsifier blend influenced the size distribution of the formed microspheres. With an increase in the amount of hydrophilic emulsifier, there was an initial increase in the percent of desired size fraction (137.5 microns) of microspheres followed by a decrease. Microspheres with a larger size released the drug slowly compared to smaller size microspheres, while increase in drug load increased the rate of drug release. The release pattern fitted the Higuchi dissolution kinetics for spherical matrices. Different impeller blade designs formed microspheres that exhibited different release rates. The microspheres (mean size 137.5 microns), had a release profile that made them suitable to be formulated as a sustained release suspension.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

The physical and chemical stability of suspensions of sustained-release diclofenac microspheres.

The major challenge in liquid sustained-release oral suspensions is to minimize drug diffusion into the suspending medium and to retain the original properties of the microparticles during storage. Diclofenac wax microspheres prepared by the hydrophobic congealable disperse phase method were formulated as a sustained release suspension and stored at three different temperatures (25, 37 and 45 degrees C) for 3 months, to evaluate the physical and chemical stability of the suspended microspheres. Suspensions of microspheres stored at ambient temperatures were both physically and chemically stable, but at higher temperatures, up to 45 degrees C, there was a decrease in drug release due to scaling and melting on the microsphere surface as observed by scanning electron microscopy. However, on prolonged storage, up to 90 days, especially at 45 degrees C, temperature became a dominant factor causing an increase in drug release. The suspension of diclofenac microspheres was chemically stable for 3 months, while the plain drug suspension exhibited slight degradation.

Anti-Inflammatory Agents, Non-Steroidal↗