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Biomedical subjects

M Hoffman

Publications and source records attributed to M Hoffman.

At least 433 records · Page 24Linked to original sources
PubMedDate not supplied

Fibrinogen content of low-volume cryoprecipitate.

Single-donor cryoprecipitate is the most convenient and reliable source of fibrinogen. A change by the regional Red Cross Blood Service to the production of low-volume cryoprecipitate led the authors to reexamine the fibrinogen content of cryoprecipitate units. The average fibrinogen content of individual low-volume (4 ml) units (n = 23) was 101 +/- 48 mg; in the 10-unit pools (n = 9 pools), content was 89 +/- 13 mg. Both measurements were considerably lower than previously published. By contrast, the mean fibrinogen content of regular-volume (15 ml) cryoprecipitate units (n = 8) was 142 +/- 50 mg. The fibrinogen was stable for at least 4 hours after thawing, and it survived refreezing and thawing.

Blood Banks↗
PubMedDate not supplied

Preparation and in vitro evaluation of heparin-loaded polymeric nanoparticles.

Nanoparticles of a highly soluble macromolecular drug, heparin, were formulated with two biodegradable polymers (poly-E-caprolactone [PCL] and poly (D, L-lactic-co-glycolic-acid) 50/50 [PLAGA]) and two nonbiodegradable positively charged polymers (Eudragit RS and RL) by the double emulsion and solvent evaporation method, using a high-pressure homogenization device. The encapsulation efficiency and heparin release profiles were studied as a function of the type of polymers employed (alone or in combination) and the concentration of heparin. Optimal encapsulation efficiency was observed when 5000 IU of heparin were incorporated in the first emulsion. High drug entrapment efficiency was observed in both Eudragit RS and RL nanoparticles (60% and 98%, respectively), compared with PLAGA and PCL nanoparticles (<14%). The use of the two types of Eudragit in combination with PCL and PLAGA increased the encapsulation efficiency compared with these two biodegradable polymers used alone; however, the in vitro drug release was not modified and remained low. On the other hand, the addition of esterase to the dissolution medium resulted in a significant increase in heparin release. The in vitro biological activity of released heparin, evaluated by measuring the anti-Xa activity by a colorimetric assay, was conserved after the encapsulation process.

Biodegradation, Environmental↗
PubMedDate not supplied

Microencapsulation of low molecular weight heparin into polymeric particles designed with biodegradable and nonbiodegradable polycationic polymers.

Owing to its lack of oral absorption, heparin has to be administered parenterally. However, parental administration has negative aspects such as multiple injections, possible infection, patient inconvenience, and high cost. Now, low molecular weight heparin (LMWH) is taking part in antithrombotic treatment and is proven to confer more advantages than unfractionated heparin. The aim of our present study was to formulate, by the w/o/w emulsification process, LMWH microparticles as potential oral carriers prepared with biodegradable (poly-epsilon-caprolactone and poly-lactic-co-glycolic acid) and nonbiodegradable polycationic polymers (Eudragit RS and RL), used alone or blended. The encapsulation efficiency ranged from 16 to 47% and was highly dependent on the presence of the positively charged polymers. In the same way, a low in vitro LMWH release was observed when Eudragit polymers composed totally or partially the polymeric matrix, compared with biodegradable polymers exhibiting higher LMWH release (40 and 60%). For each formulation, LMWH released from microparticles preserved its biological activity as shown by the antifactor Xa activity. Experiments performed with fluorescein-labeled LMWH showed the drug distribution in microparticles and may give information about the mechanisms controlling LMWH encapsulation and release.

Drug Compounding↗
PubMedDate not supplied

Hoffmann reflex profiles and strength ratios in postoperative anterior cruciate ligament reconstruction patients.

Rupture of the anterior cruciate ligament (ACL) typically leads to surgical reconstruction followed by an extensive rehabilitation program. One of the most commonly experienced complications associated with ACL rupture and reconstruction is quadriceps muscle atrophy. A clear understanding of the exact mechanisms associated with ACL related atrophy remains undocumented. The purpose of the present study was to investigate maximum H-reflex to maximum M-wave ratio as well as quadriceps deficit for both isometric and isokinetic peak torques in a post ACL reconstruction population. Forty subjects volunteered for participation in this study. The experimental group comprised 20 subjects who had undergone patellar tendon graft reconstruction of a torn ACL. A matched control group of 20 subjects were also measured for comparative purposes. The results indicated the control group had significantly higher quadriceps to quadriceps ratio than did the ACL group [t(38) = 9.05 p < .001]. In contrast, there was no difference in the H-max/M-max ratio for either group or leg. The strength findings of this study support previous findings. The spinal reflex results support the need for additional research in this area, specifically with more acutely injured subjects.

Adult↗
PubMedDate not supplied

Preparation and characterization of ethylcellulose microspheres containing 5-fluorouracil.

Ethylcellulose microspheres containing 5-fluorouracil (5-FU) were prepared by a solvent evaporation technique using light mineral oil as the continuous phase. The drug was suspended in the acetone solution of the polymer. Three drug/polymer ratios (1/1, 1/2 and 1/3) were utilized. The microspheres were studied with respect to size, drug content and surface characteristics; the higher the polymer content, the smoother the microspheres. The drug was suspended in the polymer and the drug loading was important (more than 90%) with the three types of microspheres. In vitro dissolution studies in phosphate buffer showed that the 5-FU release was dependent on the drug/polymer ratio for the 400-500 microns granulometric fraction.

Calorimetry, Differential Scanning↗
PubMedDate not supplied

Preparation of silicone microspheres by emulsion polymerization: application to the encapsulation of a hydrophilic drug.

The objective of this work was to evaluate the ability of appropriate silicone elastomers to encapsulate hydrophilic compounds in microspheres prepared according to a multiphase emulsion-polymerization process. The particle size of the microspheres can be modified by controlling the usual emulsification parameters, such as the viscosity of the different phases, shear rates and surface activity properties of additives. The encapsulation efficiencies of a hydrophilic drug, propranolol hydrochloride, were very high but its release rates were very slow. Osmotic agents such as glycerol and propylene glycol did not enhance the release rate, whereas it was slightly increased by both sodium chloride addition and higher drug loading.

Chemistry, Pharmaceutical↗
PubMedDate not supplied

Community-based tobacco control program: the Mamre study, a demonstration project.

OBJECTIVES: To assess the feasibility of a 5-year community-based tobacco control program in the community of Mamre in South Africa, while measuring the smoking and quitting rates at the beginning and end of this demonstration project. METHODS: A tobacco intervention program was developed at low cost in collaboration with the community, and involved a wide range of activities targeting people of all ages, especially those at risk for cardiovascular disease. Community members were trained to deliver smoking cessation programs and specific advice to smokers. Cross-sectional surveys were conducted in 1989 in a random sample of 1238 people, aged 15 years and older, prior to the 5-year demonstration project, and again in 1996 among 974 people at the end of the project. Demographic data and smoking and quitting patterns were collected by interviewer-administered questionnaires. Trained field workers used standardized procedures for recording blood pressure, height, and weight. RESULTS: The community participated with enthusiasm in the activities surrounding smoking cessation and the annual World No Smoking Day. The smoking rate decreased significantly between the two surveys (OR 1996/1989 = 0.82; 95% CI of 0.69-0.99), and the quitting rate increased significantly during the 5-year intervention period compared to the 5 years prior to the baseline survey (OR 1996/1989 = 0.74; 95% CI of 0.57-0.98). Men who participated in the program but continued to use tobacco in 1996 smoked more cigarettes than those who smoked in 1989. People who quit during the intervention period tended to be older, hypertensive, and obese; they consumed no alcohol, and noticed the health warnings posted in the community if they were older and had 10 or more years of education. CONCLUSIONS: A low-cost community-based tobacco control program was successfully implemented in the Mamre community. The program was received enthusiastically, built tobacco cessation skills, and significantly reduced the community's smoking rate compared to that before the demonstration project.

Adolescent↗
PubMedDate not supplied

[Desirudin (Revasc) to prevent thromboembolic complications after hip or knee replacement surgery].

Since March 1999, desirudin (REVASC), a recombinant hirudin, has been used in Nancy to treat patients who undergo total hip or knee replacement with a high risk of thromboembolic complications. We carried out a retrospective study using clinical data on the first 15 consecutive patients treated with desirudin to find out prescription motivations, type of shift (indirect anticoagulants or low-molecular-weight-heparin) and evolution. They all had a high risk of deep vein thrombosis (thrombophily, obesity, history of thromboembolic events). Some of this patients would have been excluded of the studies which permitted desirudin to be approved. In this study, we found no thromboembolic complications. The only striking facts are one bleeding complication (after difficult surgery) and one pulmonary embolism (2 months later).

Aged↗
PubMedDate not supplied

[Stability of dilute solutions of ganciclovir sodium (Cymevan) in polypropylene syringes and PVC perfusion bags].

The stability of ganciclovir sodium solutions stored in polypropylene syringes and PVC bags was tested in 0.9% sodium chloride at three concentrations 70, 200 and 350 mg/50 ml for polypropylene syringes, and two concentrations (70 and 350 mg/250 ml) for PVC bags and at three temperatures (-20 degrees C, + 4 degrees C, room temperature). The solutions, which had been initially frozen, were thawed by exposure to microwave radiations. The stability of each sample was determined by high-performance liquid chromatography. The results of this study indicate that admixtures of ganciclovir sodium at the concentration rates tested can be frozen for at least one year and are stable for at least 80 days at + 4 degrees C and 7 days at room temperature.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

[Freezing of solutions for parenteral usage: advantages and disadvantages. Nine month's experience at the pharmacy of the Hospital of Nancy].

Usually parenteral solutions can be kept longer if they are frozen. This freezing procedure assumes one knows the stability of frozen drugs. Freezing has a few drawbacks; preparations must be labelled twice (before and after freezing), only standardized doses can be prepared, thawing procedures must be established, cost of freezer and microwave-oven and time needed for thawing and labelling. There are four main advantages; production plannings are improved because time needed for preparation is reduced, quality assurance of the preparation, availability of preparation at any time, reduce of drug wastage. Freezable drugs are listed and sorted by pharmacological class. The presentation includes drug concentration, vehicle, container, storage temperature, assay procedure and stability. Our nine months experience is presented. Three drugs are frozen; methotrexate, metoclopramide and ganciclovir. Considerable preparation time is saved and economy is about FF 150,000.

France↗
PubMedDate not supplied

Unusual presentations of inflammatory conditions in cerebrospinal fluid.

Unusual inflammatory reactions in cerebrospinal fluid (CSF) in five patients were explicable by the type of intracranial injury or surgical intervention that they had received or by their basic disease process. Lumbar puncture fluid from a 64-year-old man with multiple facial fractures contained neutrophils, bacteria, Candida sp. and ciliated columnar cells, findings consistent with a basilar skull fracture allowing paranasal sinus contents to enter the subarachnoid space. A 59-year-old man with angioimmunoblastic lymphadenopathy developed meningitis and suffered a respiratory arrest; a ventricular fluid contained acute inflammatory cells as well as numerous corpora amylacea. Lumbar CSF obtained during surgery from a 26-year-old man with a pontine glioma contained numerous histiocytes clustered around polarizable filaments, probably strands of gauze introduced during surgery. A specimen of CSF obtained intraoperatively from a 54-year-old man with an acoustic neuroma undergoing a second craniotomy contained multinucleated giant cells bearing suture material. A 19-year-old girl with systemic sarcoidosis had noncaseating granulomas in the right temporal lobe and multinucleated giant cells in her CSF.

Adult↗
PubMedDate not supplied

Perceptions of nursing staff development. A replication study.

The authors, in this study, replicate the research of Kirsch (1987, 1990) and contribute to the knowledge base of nursing staff development. This replication partially supports the original research findings related to work satisfaction, organizational commitment, hospital-sponsored education, and intent to remain in the institution. An extension of the replication study was the comparison of responses from full and part-time nursing staff members.

Attitude of Health Personnel↗