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Biomedical subjects

L Micheli

Publications and source records attributed to L Micheli.

At least 37 records · Page 2Linked to original sources

High-performance liquid chromatography of flufenamic acid in rat plasma.

A simple high-performance liquid chromatographic (HPLC) method for the determination of flufenamic acid in rat plasma is described. After liquid-liquid extraction, the drug is separated by HPLC on a 5-microns octadecylsilica column (Nucleosil C18) with ultraviolet detection at 280 nm. Linear calibration graphs for flufenamic acid were constructed from 0.5 to 15 micrograms/ml. The method has been applied to a pharmacokinetic study in animals.

Animals↗

Hepatic glutathione determination after ethanol administration in rat: evidence of the first-pass metabolism of ethanol.

As a fraction of ingested ethanol is metabolized by gastric mucosa, different amounts of alcohol should reach the liver when the same dose is administered by oral or intravenous route. Therefore, we investigated the time-course of hepatic reduced glutathione (GSH) concentrations after intra-peritoneal or intra-gastric load of the same amount of ethanol in the rat. The test was also performed in fasted and Cimetidine-treated rats. The oral ethanol administration was followed by a less pronounced decrease and by a quicker recovery of hepatic content of GSH than after intraperitoneal route. In the fasted rat, basal hepatic GSH significantly decreased; after alcohol administration the decrease of hepatic GSH was more severe and prolonged than in the fed rat. Cimetidine was shown to be a potent inhibitor of gastric ADH. Pre-treatment with Cimetidine did not change the basal levels of hepatic GSH, but after oral ethanol load, the decrease of the hepatic GSH content was significantly (p < 0.005) more pronounced than in controls. This study demonstrates the beneficial effects of gastric ethanol metabolism on the liver. The reduced gastric ethanol metabolism, induced by fasting or by Cimetidine resulted in a decreased content and delayed recovery of liver GSH content.

Animals↗

Acute exertional anterior compartment syndrome in an adolescent female.

Acute compartment syndromes usually occur as a complication of major trauma. While the chronic exertional anterior tibial compartment syndrome is well described in the sports medicine literature, reports of acute tibial compartment syndromes due to physical exertion, or repetitive microtrauma, are rare. The case of an adolescent female who developed an acute anterior compartment syndrome from running in a soccer game is described in this report. Failure to recognize the onset of an acute exertional compartment syndrome may lead to treatment delay and serious complications. Whereas the chronic exertional anterior compartment syndrome is characterized by pain that diminishes with the cessation of exercise, the onset of the acute exertional anterior compartment syndrome is heralded by pain that continues, or increases, after exercise has stopped. Compartment pressure measurement confirms the clinical diagnosis and helps guide treatment. True compartment syndromes require urgent fasciotomy.

Acute Disease↗

Effect of acetaminophen on glutathione levels in rat testis and lung.

Glutathione (GSH) levels in rat testis and lung after oral administration (3 g/kg) of acetaminophen (APAP) were studied. At the administered dose APAP is present in each organ and influences the GSH levels. APAP value of 114 micrograms/g was obtained in testis at 6 hr (peak time); in the lung the Cmax was 92 mu/g at 8 hr and this value lasted several hours longer than that in testis. GSH levels are also affected differently in the organs studied after APAP administration; the lungs seem to be the primary organ undergoing the depleting action of APAP. This process could not only cause toxicity, but also predispose those organs to the action of toxic compounds responsible for specific pathologies.

Acetaminophen↗

Rapid and sensitive determination of piroxicam in rat plasma, muscle and skin by high-performance liquid chromatography.

A rapid and precise high-performance liquid chromatographic method for the determination of piroxicam in a variety of biological samples has been developed. A reversed-phase column, isocratic elution and ultraviolet detection were employed. Calibration curves were reproducible and highly linear, with correlation coefficients typically averaging over 0.992. The detection limit of the assay was 100 ng/ml for all biological samples examined (at a signal-to-noise ratio of 3:1). Validation of the method demonstrated a good sensitivity, accuracy and precision. The method has been adopted for a pharmacokinetic study in rats.

Animals↗

Non-steroidal anti-inflammatory drugs (NSAIDs) affect the glutathione (GSH) levels in the brain.

The authors in a previous research verified the effect of administration of three non steroidal antiinflammatory drugs (piroxicam, naproxen, ketoprofen) on the glutathione levels in various organs of rat. On the basis of these researches, the authors study the effect of the same anti-inflammatory drugs on glutathione levels in rat brain, dissected in order to analyze separately the cortex, cerebellum and the remaining part of the brain. The obtained results show that the distribution of the three drugs is not homogeneous in the studied areas and that these three drugs act differently on glutathione levels. These facts let us suppose that piroxicam, naproxen and ketoprofen produce toxic events that are different according to the brain areas we studied.

Animals↗

Effect of non-steroidal anti-inflammatory drugs on glutathione levels in various organs of rat.

Since glutathione (GSH) depletion (about 20% of total GSH content) can impair the cell's defence against the toxic actions of drugs and may lead to cell injury and death, we examined the effect of piroxicam, naproxen and ketoprofen on GSH levels in various organs of the rat (brain, eye, liver, stomach, heart, leg adductor muscle). Ketoprofen in brain and leg adductor muscle dramatically decreases the GSH levels, giving rise to potential cellular toxicity.

Animals↗

Regional analgesia on pediatric medical and surgical wards.

Regional anesthetic approaches to pain management were examined in 72 children and young adults (ages 3 weeks to 31 years) who were observed on the surgical or medical wards of a children's hospital separate from intensive care areas. A protocol was devised to permit safe conduct of these techniques on the ward. Full resuscitation supplies were kept at each bedside. All patients receiving epidural narcotics had an apnea monitor, hourly counting of respiratory rates, and restriction of systemic analgesics. All bolus re-injections into the catheters were performed by an anesthesiologist who monitored the patient for 20 min. Minor side-effects, including pruritus, nausea, and urinary retention were common, but manageable. Significant complications included: one case of decubitus ulcers requiring skin-grafting, one episode of mild hypotension in a patient with terminal malignancy, requiring ephedrine and phenylephrine, and one mild toxic reaction on test dosing due to presumed intravascular migration of a lumber sympathetic catheter. Regional analgesic techniques can provide excellent analgesia on the wards for selected children and young adults, provided precautions are taken. Further study is required to define specific indications, risks and benefits relative to simpler techniques.

Adolescent↗

Distraction lengthening for the congenitally short metatarsal: a case report.

Distraction lengthening has gained wide acceptance in general orthopedics and in upper extremity reconstructions. The application of this technique to the foot is presented. The congenitally short fourth metatarsal of a 16-yr-old girl was successfully lengthened by a two-stage procedure. At the first stage, an open diaphyseal osteotomy was performed and the distraction apparatus was secured. Over the ensuing 5 weeks, 36 mm of distraction was achieved. At the second stage, the distracted gap was filled with a fibular bone graft. Following uncomplicated healing, there was no gait, intrinsic muscle, or tendon abnormalities. Metatarsal distraction lengthening can be safely accomplished provided there is good bone stock, adequate soft tissue, and a cooperative patient.

Adolescent↗

Effect of buspirone on glutathione hepatic levels in rat.

The effect of oral administration of buspirone (0.5-1.0 and 2.0 mg/Kg) on GSH levels was studied in rat liver. The modulating activity of buspirone on hepatic content of this tripeptide is clearly opposite to that of DAZ, put into evidence by us in previous works. Thus our observations let us hypothesize a different mechanism of action for buspirone than that for benzodiazepines.

Administration, Oral↗

Glutathione (GSH) in human stomach mucosa.

The role of glutathione and its function in patients affected by carcinoma and ulcer was studied. The dramatical decrease of this tripeptide evidenced by the authors, demonstrates its fundamental role in the above mentioned pathologies and permits to formulate a hypothesis of therapeutic presidium for some substances (e.g. cysteine), that showed to be able in recovering normal glutathione levels.

Adult↗

Bone stress lesions in ballet dancers: scintigraphic assessment.

Ballet dancers are athletes susceptible to ligamentous and bony injury. We reviewed retrospectively the bone scans (technetium-99m methylene diphosphonate) of 23 ballet dancers with pain in the back and/or lower extremities to determine the usefulness of scintigraphy in the detection of stress lesions of bone. The scintigraphic studies in 19 dancers identified multiple areas of stress injury in both symptomatic and asymptomatic locations. Thirteen dancers had 22 stress fractures (microfractures of trabeculae with associated bone repair) manifested by an intense focus of increased uptake of radiopharmaceutical, and 19 dancers had stress reactions (areas of accelerated remodeling and resorption of bone) demonstrated by diffusely increased uptake of radiotracer. Ten of the 13 dancers with stress fractures were symptomatic and six of the 19 dancers with stress reactions were symptomatic. The radiographs of 10 dancers with positive bone scans were normal or showed no distinction between acute and chronic injuries. Stress fractures were most prevalent in the feet, and stress reactions were most prevalent in the tibiae. The study confirmed that ballet dancers sustain significant bone stress in their legs and feet. Our results show that scintigraphy can be used to detect stress fractures and stress reactions at both symptomatic and asymptomatic sites in this population.

Adolescent↗

Thiazolidine-4-carboxylic acid toxicity and glutathione levels in various organs of the rat.

Thiazolidine-4-carboxylic acid (TC) (a precursor of intracellular cysteine) was administered to rats at 50 mg/kg and at 400 mg/kg by an i.p. route and at 800 mg/kg per os, and the levels of glutathione (GSH) in gastric mucosa, gastric wall and liver were determined. GSH levels in the eyes were measured after oral administration of TC. No changes in GSH levels were observed at 50 mg/kg from 1 to 48 h. An initial increase of liver GSH levels was followed by a decrease (up to 12 h) at 400 mg/kg i.p. After oral administration of 800 mg/kg an initial increase of GSH levels in the liver and gastric mucosa was followed by a decrease (up to 24 h); the GSH levels in the gastric wall showed a persistent decrease. No significant changes were seen in the GSH levels of the eyes.

Animals↗

Mechanoreceptors in human cruciate ligaments. A histological study.

We obtained human cruciate ligaments at the time of total knee replacement and from autopsy and amputation specimens, and examined histological sections of the ligaments for the presence of mechanoreceptors using the Bodian, Bielschowsky, and Ranvier gold-chloride stains for axons and nerve-endings. The cruciate ligaments obtained at the time of total knee replacement were too distorted by disease processes to be of use. The autopsy and amputation specimens, however, contained fusiform mechanoreceptor structures measuring 200 by seventy-five micrometers, with a single axon exiting from the capsule of the receptor. One to three receptors were found at the surface of each ligament beneath the synovial membrane, and were absent from the joint capsules and menisci. Morphologically the receptors resembled Golgi tendon organs, and it seems likely that they provide proprioceptive information and contribute to reflexes inhibiting injurious movements of the knee. This is the first histological demonstration of mechanoreceptors in human cruciate ligaments.

Aged↗