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Biomedical subjects

A Margolis

Publications and source records attributed to A Margolis.

At least 19 recordsLinked to original sources
PubMed1999

A method of reducing the opioid withdrawal intensity using progressively increasing doses of naloxone.

We assessed the withdrawal intensity in acutely morphine-dependent mice using a pretreatment with escalating doses of naloxone. All animals received a single dose of morphine (100 mg/kg) for the induction of acute opioid dependency. Group 1 (control) received three injections of normal saline and then naloxone 0.8 mg/kg. Group 2 received increasing pretreatment doses of naloxone (0.1, 0.2, and 0.4 mg/kg) and a challenge dose of 0.8 mg/kg. Group 3 received three injections of naloxone 0.1 mg/kg and a challenge dose of 0.8 mg/kg. Groups 4 and 5 were used to verify whether ED(50) found in previous studies was comparable with values obtained in the current experiments. The withdrawal intensity was determined by the number of jumps. The mice of group 1 exhibited significantly more jumps after 0.8 mg/kg of naloxone as compared with group 2. The number of jumps in response to naloxone between groups 1 and 2 and groups 2 and 3 was not significantly different. The results show that pretreatment with increasing naloxone doses significantly reduced the withdrawal intensity as compared with the control group; whereas pretreatment with repeated low antagonist did not reduce it significantly.

Animals↗
PubMed1999

New uses of legacy systems: examples in perinatal care.

In this article, new uses of the Perinatal Information System at the Uruguayan Social Security health care facilities are described. The perinatal information system has been in place for over 13 years, with about 40 thousand clinical records on electronic files. A newly created Web interface allows a distributed access to existing perinatal information within the National Social Security Wide Area a Network. Perinatal data is also exported to a management information system, allowing to dynamically answer questions and make managerial decisions, and eventually link these data with other sources. Future steps regarding clinical information systems are outlined.

Humans↗
PubMed1995

Dopa reaction of fetal melanocytes before and after skin transplantation on to nude mice.

We have previously demonstrated that human fetal epidermal melanocytes are dopa-negative. The present study was conducted to test the hypothesis that human fetal melanocytes can be activated to produce melanin under conditions differing from their natural in utero environment. To address this question, dopa staining activity of fetal epidermal sheets, obtained from seven aborted fetuses with estimated gestational ages of 13-20 weeks, was evaluated before and after engraftment on to nude mice. Dopa staining became positive 7 days post-engraftment. The intensity of the dopa reaction and the mean number of melanocytes increased by day 14 post-engraftment, and these changes were even greater by day 30. These observations indicate that human fetal melanocytes, potentially capable of synthesizing melanin under conditions differing from their normal in utero environment, are either inhibited, or not stimulated to do so.

Adult↗
PubMed1995

Computerized practice guidelines for heart failure management: the HeartMan system.

In this paper we discuss the initial stages of development and evaluation of the HeartMan system, a set of computerized practice guidelines for heart failure management. The concept of computerized guidelines as a hybrid of expert systems and practice guidelines methodologies and techniques is proposed. We show the results of the initial evaluation of the system, which are very promising, although the sample size is small, and the study is retrospective: Of 177 messages, 90% were considered appropriate, of which 97.5% would have been followed. Eight percent of the messages were classified as neutral, and 2% classified as inappropriate. The errors were correctable by changing the logic. The potential technical and sociological barriers to the complete development and clinical use of the system are discussed.

Expert Systems↗
PubMed1994

Warfarin 2.0--a computer program for warfarin management. Design and clinical use.

Warfarin 2.0 is a computer program that helps physicians optimize treatment of outpatients with warfarin. The main reason for its development was to achieve a good anticoagulation level, avoiding both undertreatment--which causes thromboembolic complications--and overtreatment--which causes hemorrhagic complications. The program was also designed to help educate the anticoagulated patient, standardize warfarin management and audit results of what had been done. The philosophy of continuous quality improvement was applied. Warfarin 2.0 is in clinical operation in the University Hospital, Montevideo, Uruguay, and it has also been used since the end of 1993 in the Favaloro Foundation, Dept. of Hematology, Buenos Aires, Argentina. The results from the first 15 months of use in Montevideo showed an increase in the number of patients being followed (from 91 to 132) and the average number of visits per patient (from one visit every 10.6 weeks to one every 6.5 weeks): The frequency of visits has been in the internationally accepted ranges since the program was implemented. Better anticoagulation levels were achieved after an adjusting period. Unfortunately, the number of undertreated patients is still large, and a thorough analysis of the data is going to be undertaken to continue improving warfarin management.

Drug Therapy, Computer-Assisted↗
PubMed1991

The protective efficacy of polyvalent pneumococcal polysaccharide vaccine.

BACKGROUND: Although the protective efficacy of pneumococcal polysaccharide vaccine has been demonstrated in randomized trials in young African gold miners, there has been controversy about its efficacy in older Americans at risk for serious pneumococcal infections. To assess the vaccine's protective efficacy against invasive pneumococcal infections, we conducted a hospital-based case-control study of the efficacy of pneumococcal vaccine in adults with a condition recognized to be an indication for receiving the vaccine. METHODS: From 1984 to 1990, adults in whom Streptococcus pneumoniae was isolated from any normally sterile site were identified by prospective surveillance in the microbiology laboratories of 11 large hospitals; those with an indication for pneumococcal vaccine were enrolled as case patients. For each case patient, one control was matched according to age, underlying illness, and site of hospitalization. We contacted all providers of medical care to ascertain each subject's history of immunization with pneumococcal vaccine. Isolates of S. pneumoniae were serotyped by an investigator unaware of the subject's vaccination history. RESULTS: Thirteen percent of the 1,054 case patients and 20 percent of the 1,054 matched controls had received pneumococcal vaccine (P less than 0.001). When vaccine was given in either its 14-valent or its 23-valent form, its aggregate protective efficacy (calculated as a percentage: 1 minus the odds ratio of having been vaccinated times 100) against infections caused by the serotypes represented in the vaccine was 56 percent (95 percent confidence interval, 42 percent to 67 percent; P less than 0.00001) for all 983 patients infected with a serotype represented in the vaccine, 61 percent for a subgroup of 808 immunocompetent patients (95 percent confidence interval, 47 percent to 72 percent; P less than 0.00001), and 21 percent for a subgroup of 175 immunocompromised patients (95 percent confidence interval, -55 percent to 60 percent; P = 0.48). The vaccine was not efficacious against infections caused by serotypes not represented in the vaccine (protective efficacy, -73 percent; 95 percent confidence interval, -263 percent to 18 percent; P = 0.15). CONCLUSIONS: Polyvalent pneumococcal vaccine is efficacious in preventing invasive pneumococcal infections in immunocompetent patients with indications for its administration. This vaccine should be used more widely.

Adolescent↗
PubMed1980

Flavor preexposures in a conditioned taste aversion situation: a dissociation of behavioral and endocrine effects in rats.

A series of experiments examined the effects of flavor preexposures on pituitary-adrenal/behavior relations in a conditioned taste aversion paradigm. It was found that reexposure to a novel milk solution paired earlier with lithium chloride (LiCl) elicited conditioned activation of the pituitary-adrenal system (Experiment 1). The unconditioned response to LiCl (measured by changes in plasma levels of corticosterone) did not vary as a function of prior (2 and 5 vs. 10) exposures to the milk solution (Experiment 2). Increased familiarity with the substance (resulting from 10 prior exposures) rendered the conditioning of a taste aversion to this substance less effective. Further, reexposure to this familiar substance after its pairing with LiCl was not accompanied by the characteristic conditioned pituitary-adrenal activation (Experiment 3). By titrating the number of conditioned stimulus (CS) preexposures (Experiment 4) it was found that within the range of preexposures manipulated (5-10), subjects exhibited (a) a coupling of behavioral and pituitary-adrenocortical responses when the conditioned taste aversion to the milk solution was paralleled by elevated plasma corticosterone (5-6 preexposures), (b) a coupling of these two response systems when flavor consumption was accompanied by suppressed plasma titers of corticoids (9-10 preexposures), or (c) a dissociation of the two system when the conditioned taste aversion was not accompanied by conditioned adrenocortical activity (7-8 preexposures). These data are discussed in terms of a dissociation in the effects of CS preexposures on conditioned adrenocortical and behavioral response systems.

Adrenocorticotropic Hormone↗
PubMed1977

Intestinal calcium-binding protein 3 months after massive small bowel resection in the piglet.

Changes in intestinal calcium-binding protein and calcium binding activity were studied at resection and 3 months after 90% small bowel resection in piglets and one adult pig. A calcium-binding protein (MW congruent to 11.000) with calcium-dependent eletrophoretic mobility was partially purified from mucosal extract of proximal jejunum, mid-gut, and ileum. The concentration of calcium-binding protein and the calcium-binding activity of the intact animals were found highest in the proximal jejunal segment, lowest in the ileal segment. After resection in the four surviving animals out of nine, a significant increase in calcium-binding activity was observed in the proximal jejunum and in the distal ileal segment. The change in calcium-binding activity was much more marked in the ileum than the jejunum. These data demonstrate that pig intestinal mucosa possesses an adaptive capacity to increase the synthesis of calcium-binding protein after massive small bowel resection.

Adaptation, Physiological↗
PubMed1977

Serum antibodies before and after immunisation in haemodialysed children.

Serum antibodies (AB) have been measured before and after vaccination in haemodialysed children. The main finding was a normal increase in AB titres following adsorbed vaccines (diphtheria, tetanus, pertussis and poliomyelitis) demonstrating a normal humoral immune ability. By contrast, a poor response to live attenuated viruses (poliomyelitis and measles) was observed. Two additional findings were an inhibitor effect of tetanus toxoid in mice by uraemic serum, and a constant negative Schick test indicative of suppressed non-specific skin reactivity.

Adolescent↗
PubMed1976

Effects of 25-hydroxycholecalciferol on bone lesions of children with terminal renal failure.

Quantitative histology was performed on serial iliac crest biopsies obtained from 14 children with terminal renal failure. A long-term study on the comparative effects of vitamin D2 and 25-hydroxycholecalciferol [25-(OH)D3], in five patients with severe lesions of osteomalacia and/or osteitis fibrosa, demonstrated the efficiency of 25 to 200 mug/day of 25-(OH)D3 and the lack of therapeutic action of 345 to 685 mug/day of vitamin D2. In nine subjects with normal roentgenograms or minimal skeletal alterations, the first biopsy taken at the beginning of intermittent hemodialysis showed evidence of defective mineralization and/or lesions of resorption. Four of these children were treated with 25-(OH)D3 (25 to 50 mug/day) and calcium supplementation orally (0.5 to 1.5 g/day); five children received calcium orally (0.5 to 0.75 g/day) alone. Aggravation of bone lesions during intermittent hemodialysis was observed in patients treated with calcium supplements alone. In subjects who were given 25-(OH)D3, mineralization improved and marrow fibrosis disappeared. However, as the two groups of patients were different in composition and in the manner in which they were treated, it is difficult to state whether the beneficial effects observed were solely attributable to 25-(OH)D3 administration. 25-(OH)D3 therapy induced severe intoxication in two patients. A rise in plasma calcium concentration to 11.0 to 11.5 mg/100 ml was observed in two other patients. It is concluded that: a) pharmacologic doses of 25-(OH)D3 are highly effective in healing bone lesions of children with terminal renal failure; b) such treatment requires strict clinical surveillance as 25-(OH)D3 intoxication may occur even in anephric patients.

Adolescent↗