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Biomedical subjects

L Graff

Publications and source records attributed to L Graff.

At least 37 records · Page 2Linked to original sources
PubMed1995

In vitro and in vivo evaluation of potential aluminum chelators.

The potential for aluminium (Al) chelation by different compounds was determined using 2 in vitro techniques. The formation of stable complexes with Al in an aqueous solution was evaluated using pulse polarography. This technique allowed the influence of temperature and calcium (Ca) to be studied for each compound. Certain compounds (EDDHA, HAES, citric acid and HBED) showed great chelation in the absence of Ca2+ at a temperature of 37 +/- 1 C. An ultrafiltration technique combined with Al determination by atomic emission spectroscopy allowed the efficiency of different substances to complex Al that were previously bound to serum proteins to be estimated. The kinetics of chelation and minimum efficient concentration have been determined for all products studied. EDDHA had chelation potential similar to DFO. The real efficacies of the compounds were studied in vivo to compare the effectiveness of repeated administrations of the best chelating agents (EDDHA, DFO, HAES and tartaric acid) on the distribution and excretion of Al after repeated i.p. administrations to rats. Intraperitoneal EDDHA significantly increased urinary metal (Al, Ca, Cu, Fe and Zn) excretion. These excretions may be correlated to a renal toxic potential property.

Aluminum↗
PubMed1995

A possible non-aluminum oral phosphate binder? A comparative study on dietary phosphorus absorption.

The aim of this study was to highlight a possible new non-aluminum phosphate-binder to limit hyperphosphatemia in patients with renal failure. Lanthanum chloride hydrate was evaluated as a dietary phosphate binder in rats. Aluminum chloride hexahydrate was evaluated as a reference. Animals were divided in five groups (6 animals per group): 1 control group (C), 2 aluminum groups (Al1 and Al2), receiving different doses of aluminum chloride hexahydrate and 2 lanthanum groups (La1 and La2), receiving different doses of lanthanum chloride hydrate. During the treatment, urine and stools were collected. At the end of the treatment animals were sacrificed and plasma and different organs were collected (liver, spleen, kidneys, brain and femur). To highlight the possible transfer of lanthanum in rat tissues, a long-term (100 days) study was carried with a high dose. At the end of the treatment, lanthanum determinations were carried out on several tissues (liver, spleen, kidneys, brain, femur and lungs). Determinations of phosphorus and calcium levels in plasma indicated that lanthanum chloride hydrate showed as good results as aluminum chloride hexahydrate. Lanthanum chloride hydrate significantly (p < 0.01) reduced the bone phosphorus burden. Decreases of urinary excretion and increases in fecal excretion of phosphorus indicated a severe phosphorus depletion in all treatments (Al and La). Unfortunately, in the long-term study, lanthanum traces could only be determined in the different tissues but not in plasma. However, in comparison with the equivalent aluminum treatment, the transfer of lanthanum was less important than aluminum transfer. Consequently, lanthanum could provide a possible alternative to aluminum.

Administration, Oral↗
PubMed1995

Reduction of dietary phosphorus absorption by oral phoshorus binders.

The aim of this study was to study a possible new non-aluminum phosphate-binder to limit hyperphosphatemia in patients with renal failure. Zirconyl chloride octahydrate was evaluated as a dietary phosphate binder in rats. Aluminum chloride hexahydrate was used as a reference. Animals were divided into six groups (6 animals per group): One - control group (C), two - aluminum groups (Al1 and Al2) and three - zirconium groups (Zr1, Zr2 and Zr3) receiving different doses of zirconyl chloride octahydrate. Urines were collected during the experimental period. At the end of the treatment, the animals were sacrified and plasma and different organs were collected (liver, spleen, kidneys, brain and femur). Determination of phosphorus and calcium levels in plasma indicated that zirconyl chloride octahydrate yielded as good results as aluminum chloride hexahydrate did. Zirconyl chloride octahydrate significantly (p<0.01) reduced bone phosphorus burden. Urinary excretion of phosphorus indicated a severe phosphorus depletion in all treatments. Not even traces of zirconium could be determined in the different tissues, in urines or in plasma. Consequently, it is important to carry out experiments with zirconium compounds in order to develop non-aluminum-containing phosphate binders.

Administration, Oral↗
PubMed1991

Probability of appendicitis before and after observation.

STUDY OBJECTIVE: To examine patients with abdominal pain for changes in probability of appendicitis during observation. STUDY DESIGN: Retrospective cohort study. SETTING: University-affiliated community hospital. METHODS: 252 patients with abdominal pain who were examined underwent short-term (10.4 hours) observation (95% confidence interval [CI], 8.7, 12.1) before the decision to operate during a one-year period. Alvarado's scoring system and a probability-of-diagnosis nomogram were used to assign scores and estimate probability of appendicitis. MEASUREMENTS AND RESULTS: In the study group, mean score of patients with appendicitis increased after observation from 6.8 (95% CI, 6.2, 7.4) to 7.8 (95% CI, 7.3, 8.3), corresponding to a change in probability of appendicitis from 50% to 65%. Mean score of patients without appendicitis decreased from 3.8 (95% CI, 3.5, 4.1) to 1.6 (95% CI, 1.58, 1.62), corresponding to a change in probability from 35% to 22%. The difference between mean scores for patients with and without appendicitis increased from 2.6 (95% CI, 2.0, 3.2) to 6.2 (95% CI, 6.15, 6.25) during observation. The study group initially had intermediate probability of appendicitis (score, 4.35; 95% CI, 4.04, 4.66) compared with high probability for patients who went directly to surgery after their initial evaluation (63 patients; score, 7.59; 95% CI, 7.05, 8.73) and low probability for patients with abdominal pain who were sent home after their initial evaluation without observation or surgery (2,097 patients; score, 1.87; 95% CI, 1.48, 2.26). CONCLUSION: In this group of patients with intermediate initial probability of appendicitis, observation improved the ability to distinguish patients with from those without appendicitis.

Abdominal Pain↗
PubMed1990

End-tidal CO2 detection.

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Diagnostic Techniques and Procedures↗
PubMed1988

Decision to hospitalize: objective diagnosis-related group criteria versus clinical judgment.

Three hundred fifty patients in an observation unit attached to an emergency department received diagnostic workup of nine critical diagnostic syndromes (abdominal pain, flank pain, headache, possible cerebrovascular accident, chest pain, dizziness or syncope, head injury, seizure, multiple trauma). The decision to hospitalize for acute care after observation for 11.1 +/- 3.9 hours was examined. The objective diagnosis-related group (DRG) criteria for admission were compared retrospectively with the physician's clinical judgment of need for hospitalization. Clinical outcome was used to establish the correctness of the decision to hospitalize. Clinical judgment was compared with objective DRG criteria for reliability in predicting the presence of serious pathology necessitating acute care hospitalization; respective values were sensitivity, 100% vs 76%; specificity, 86% vs 80%; positive predictive value, 75% vs 62%; and negative predictive value, 100% vs 89%. The difference between the sensitivity of the two admission criteria was highly significant (P less than 10(-8); chi 2, 26.12). We conclude that the physician's clinical judgment outperforms DRG objective criteria in identifying which patients with critical diagnostic syndromes need acute care hospitalization for emergency medical or surgical therapy.

Decision Making↗