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Biomedical subjects

L M Sanders

Publications and source records attributed to L M Sanders.

33 records · Page 2Linked to original sources
PubMed1989

CT of primary lymphoma of the liver.

Primary lymphoma of the liver is a rare disease. In each of six cases, a large, often poorly defined mass of low attenuation was present within the liver. Four lesions originated in the right lobe and two originated in the left lobe. Satellite nodules were seen at presentation in one case and developed after presentation in two others. Other features, such as enhancement after contrast administration, necrosis, and calcification, were variable. Three of six lesions had areas of very low density, suggestive of necrosis. One mass had calcifications. After IV contrast administration, no enhancement occurred in three tumors, patchy enhancement occurred in two, and an enhancing ring was seen in the remaining tumor. The radiologic presentation of primary lymphoma of the liver differs from that of secondary involvement of the liver in systemic lymphoma. Whereas secondary lymphoma is often diffusely infiltrative and difficult to detect on CT, the lesions of primary lymphoma of the liver are easily identified on CT scans even before the administration of IV contrast material. Although rare, primary lymphoma of the liver should be included in the differential diagnosis of a large, hypodense liver mass on CT.

Adult↗
PubMed1988

Primary lymphoma of the liver.

Nine adult white men ranging in age from 27 to 76 (mean, 55 years) were treated for primary hepatic lymphoma between 1972 and 1986 at the Memorial Sloan-Kettering Cancer Center. Six patients presented with right upper quadrant or epigastric pain or discomfort, and three patients complained of fatigue and lethargy. Fever and night sweats were evident in two, and two patients had lost weight. One patient was asymptomatic; the liver mass was detected during the work-up for cancer of the prostate. Seven patients on whom computerized tomography was performed all had solitary masses in the liver although in three of them tumor had extended into both lobes as noticed at surgery. One had additional porta hepatic lymph node metastasis. Eight patients underwent an exploratory laparotomy; four had hepatic resection, and four had wedge biopsies of unresectable liver tumor. One patient had a percutaneous needle biopsy of the liver. Eight patients received combination chemotherapy. Six patients are alive, five of whom are in initial complete remission. All three patients who died had persistent or recurrent disease in the liver. The results of therapy and surgery to date in these and in other cases in the literature are encouraging.

Adult↗
PubMed1988

Percutaneous absorption of nicardipine and ketorolac in rhesus monkeys.

Vehicle effects on the percutaneous absorption of nicardipine base, nicardipine hydrochloride, ketorolac acid, and ketorolac tromethamine were determined using the rhesus monkey as an in vivo model for human skin penetration. Vehicles investigated included blends of propylene glycol, trimethylene glycol, ethanol, Azone, Tween 20, water, and long-chain fatty acids. Formulations were prepared such that the compound dose, application area, and percentage saturation of the compound in the vehicle were held constant. Variations in absorption of the compounds were therefore attributable to vehicle effects. Each formulation was applied to three monkeys for a period of 24 hr using 10 Hill Top Chambers. Plasma samples were taken at appropriate intervals for 36 to 48 hr. The results indicated that trimethylene glycol and Tween 20 did not enhance absorption of the test compounds despite claims by other investigators. Azone and ethanol provided moderate enhancement of both the rate and the extent of absorption, while long-chain fatty acids in combination with propylene glycol significantly enhanced penetration. In general, higher fluxes were observed with the more lipophilic compounds nicardipine base and ketorolac acid as compared to the hydrochloride and tromethamine salts.

Animals↗
PubMed1986

Prolonged controlled-release of nafarelin, a luteinizing hormone-releasing hormone analogue, from biodegradable polymeric implants: influence of composition and molecular weight of polymer.

The release of the peptide hormone nafarelin, 5-oxo-L-prolyl-L-histidyl-L-tryptophyl-L-seryl-L-tyrosyl-3-(2-naphthyl)- D-alanyl-L-leucyl-L-arginyl-L-prolylglycinamide, a potent luteinizing hormone-releasing hormone (LHRH) agonist, from implants of the biodegradable copolymer poly(d,l-lactide-co-glycolide) (PLGA) has been studied both in vivo and in vitro. The release has a triphasic profile typical for bulk-eroding monolithic controlled-release systems, characterized by a secondary phase of lower release preceded and followed by phases of higher release. The primary factor controlling the peptide release profile is polymer erosion, which in turn may be controlled by modifying physical properties of the polymer such as the molecular weight or the ratio of the more hydrophobic lactic acid monomer to the less hydrophobic glycolic acid monomer. The duration of the secondary phase has been found to be directly proportional to the molecular weight of the copolymer, and the total duration as well as the duration of the secondary phase are both directly proportional to the monomer ratio. A system has been identified in which the secondary phase is sufficiently reduced to provide essentially continuous efficacy in the rat for greater then eight months, with partially effective levels of release of nafarelin continuing beyond 15 months.

Animals↗
PubMed1984

Controlled release of a luteinizing hormone-releasing hormone analogue from poly(d,l-lactide-co-glycolide) microspheres.

The performance in vivo of nafarelin acetate, a potent analogue of luteinizing hormone-releasing hormone, microencapsulated in poly(d,l-lactide-co-glycolide), was evaluated. The influence of polymer composition and molecular weight on the estrus-suppressing activity of the microspheres in female rats was determined. Compound release was shown to be effected by polymer erosion rather than by diffusion. A triphasic release of compound was observed, which was adjusted by altering the critical parameters of the polymer. A mechanism for the release of the compound was proposed. The primary release phase was compound loss by diffusion from the surface of the microspheres. The secondary phase of subeffective rates of release occurred concomitantly with polymer hydrolysis and a decrease in its molecular weight, although it remained insoluble. Dissolution of low-molecular weight fragments and erosion of the bulk of the polymer then initiated the tertiary phase of release of compound.

Animals↗
PubMed1980

Availability of tritium from non-aqueous solutions of [1,2-3H]methyltestosterone, administered orally to rats.

The solvent-water distribution coefficients of 17 alpha-methyltestosterone have been determined in selected alkanes, alkanols and alkane-alkanol blends. The oral availability of tritium from solutions of [3H]methyltestosterone in these solvents and blends was studied in rats by measuring radioactivity in plasma, faeces and urine. Disappearance of radioactivity from the gut and biliary recirculation of 3H were also examined. Variation of the solvent led to marked changes in the absorption of radioactivity, suggesting a possible method of varying bioavailability from soft gelatin capsules. Neither distribution coefficients nor tritium concentrations changed significantly from one homologue to another, but there was a marked difference when the alkane series was compared with the alkanol series. Blends of octane and octanol, together with the pure solvents, provided a suitable spread of distribution coefficients and tritium concentrations, but no simple relationship could be established between the two properties.

Administration, Oral↗
PubMedDate not supplied

Drug delivery systems and routes of administration of peptide and protein drugs.

The unique requirements of peptides and proteins in designing delivery systems, and the unprecedented recent growth in the field, has driven a great deal of research into novel means of drug delivery. The search for approaches that provide formulations that are stable, bioavailable, readily manufacturable, and acceptable to the patient, has led to major advances in development of nasal and controlled release technology. The field of parenteral solution technology has also seen some new demands made of it, and what was formerly a conventional area of formulation technology has made scientific advances to meet the needs of these compounds. At the same time, strides are being made in fundamental research in areas including oral delivery, transdermal delivery, and pulsatile and 'on demand' delivery of peptides and proteins.

Animals↗
PubMedDate not supplied

Role-modeling healthy behavior: peer counseling for pregnant and postpartum women in recovery.

The utilization of paraprofessional peer counselors for pregnant and postpartum women in recovery represents a nonthreatening and innovative departure from conventional medical and social service models. However, it must be acknowledged that these are women in recovery confronting the same daily stresses as their clients. In essence, they require the same social support services as their clients. Therefore, program planners must be reminded to build in the necessary social support systems for them at the outset. The rewards in terms of the peer counselors' capacity to engage and retain women with whom they can identify and help is well worth the investment. As a consequence of extensive community outreach and supportive activities undertaken by peer counselors, barriers to client receptivity may be removed, greater compliance and service utilization will be achieved, and the potential for successful recovery will be enhanced.

Alcoholism↗
PubMedDate not supplied

Pneumoperitoneum resembling air in the biliary tree: CT features.

The various CT appearances of free abdominal air have been described. We present a hitherto undescribed CT manifestation of this condition. When subhepatic free air tracks along the porta hepatis and suspensory ligaments of the liver, it may resemble biliary air.

Aged↗
PubMedDate not supplied

Nafarelin controlled release injectable: theoretical clinical plasma profiles from multiple dosing and from mixtures of microspheres containing 2 per cent, 4 per cent and 7 per cent nafarelin.

Nafarelin controlled release injectable (CRI) releases a decapeptide drug for target one month therapy. Nafarelin, a luteinizing hormone releasing hormone agonistic analogue, is microencapsulated in biodegradable poly(lactide-co-glycolide) microspheres and given by intramuscular injection. Clinical data from a human single dose Phase I clinical study are modelled to develop theoretical multiple dose profiles and theoretical single dose profiles from mixtures of two or three formulations. Single dose injections of nafarelin CRI microspheres (4 mg nafarelin) containing 2, 4, or 7 per cent nafarelin all achieve useful plasma drug levels throughout the target 30 day interval. Therapeutic suppression of testosterone levels was observed in all subjects participating in the phase I clinical study. Highest plasma nafarelin levels are achieved in the 0-10 and 20-35 day post-injection intervals. Theoretical multiple dosing profiles generated from the single dose clinical results show significant oscillations in plasma nafarelin levels depending on the particular dosing interval selected. Thirty or forty day dosing intervals yield significant variability in plasma nafarelin levels at steady state; 15 day dosing intervals show less variability. Therapeutic testosterone suppression was observed in the single dose study, so the nafarelin dose per injection can be reduced in multiple dosing therapies. Theoretical plasma nafarelin profiles from certain mixtures of 2 and 4 per cent nafarelin microspheres or 2 and 7 per cent nafarelin microspheres indicate that a 60 day product could be achieved. In general, all three formulations yield their lowest plasma drug levels during the 10-20 day post-injection interval. Therefore any mixture of these formulations will likewise exhibit low plasma drug levels during this interval.

Computer Simulation↗