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Biomedical subjects

L Lambrecht

Publications and source records attributed to L Lambrecht.

At least 19 recordsLinked to original sources
PubMed2000

The pharmacokinetics of ziprasidone in subjects with normal and impaired renal function.

AIMS: To assess whether renal impairment influences the pharmacokinetics of ziprasidone, and to determine whether ziprasidone is cleared via haemodialysis. METHODS: Thirty-nine subjects with varying degrees of renal impairment were enrolled into an open-label, multicentre, multiple-dose study and assigned to four groups according to their renal function: normal (group 1, creatinine clearance > 70 ml min(-1); mildly impaired (group 2, creatinine clearance 30-60 ml min(-1); moderately impaired (group 3, creatinine clearance 10-29 ml min(-1), and severely impaired (group 4, requiring haemodialysis three times-a-week). Subjects received ziprasidone 40 mg day(-1), given orally with food, as two divided daily doses for 7 days and a single 20 mg dose on the morning of day 8. Pharmacokinetic variables were determined from multiple venous blood samples collected on days 1 and 8 (haemodialysis day for subjects with severe renal impairment). Additional samples were collected from subjects with severe renal impairment on day 7 (nonhaemodialysis day). RESULTS: On day 1 there were no statistically significant differences in the pharmacokinetics (AUC(0, 12 h), Cmax, tmax) of ziprasidone among subjects with normal renal function and those with mild, moderate and severe renal impairment. The AUC(0,12 h) and Cmax in subjects with mildly impaired renal function were statistically significantly greater than in those with moderately impaired renal function (P = 0.0163-0.0385). The mean AUC(0,12 h) was 272, 370, 250 and 297 ng ml(-1) h in groups 1, 2, 3 and 4, respectively. Corresponding mean Cmax values were 47, 61, 41 and 50 ng ml(-1) and corresponding mean tmax values were 5, 6, 5 and 5 h. On day 8 there were no statistically significant differences in the pharmacokinetics (AUC(0,12 h), Cmax, tmax, lambda(z), Fb) of ziprasidone among subjects with normal renal function and those with moderate or severe renal impairment. The AUC(0,12 h) in subjects with mild renal impairment was statistically significantly greater than those in the other three groups (P = 0.0025-0.0221), but this was not considered clinically significant. The mean AUC(0,12 h) were 446, 650, 389 and 427 ng ml(-1) h in groups 1, 2, 3 and 4, respectively. Corresponding mean Cmax values were 68, 93, 54 and 70 ng ml(-1), corresponding mean tmax values were 4, 5, 4 and 5 h and corresponding mean lambda(z) were 0.14, 0.11, 0.14 and 0.17 h(-1). The mean percentage Fb was 99.84-99.88% across all groups and the mean t(1/2),z ranged from 4.2 to 6.4 h. Comparison of the mean AUC(0,12 h) and Cmax values in subjects with severe renal impairment on day 7 with those on day 8 suggested that haemodialysis does not have a clinically significant effect on the pharmacokinetics of ziprasidone. CONCLUSIONS: The findings of this study indicate that mild-to-moderate impairment of renal function does not result in clinically significant alteration of ziprasidone pharmacokinetics and therefore does not necessitate dose adjustment.

Adolescent↗
PubMed2000

Safety of intravenous gadolinium (Gd-BOPTA) infusion in patients with renal insufficiency.

The safety of gadolinium (Gd-benzyloxypropionictetra-acetate [BOPTA] dimeglumine) infusion was evaluated in 32 patients with severe or moderate chronic renal failure in a prospective, randomized, double-blind, placebo-controlled study. Renal failure was defined as severe if creatinine clearance was between 10 and 29 mL/min, and as moderate if creatinine clearance was between 30 and 60 mL/min. Serum creatinine level and 24-hour urine samples for creatinine clearance were followed up serially for 7 days after the administration of either gadolinium (Gd-BOPTA dimeglumine), 0.2 mmol/kg, or a saline infusion. No patient experienced a significant change in renal function, defined as an increase in serum creatinine level greater than 0.5 mg/dL more than baseline, and no patient required hospitalization or dialysis during the study period. Gadolinium (Gd-BOPTA dimeglumine) appears to be well tolerated in patients with moderate to severe renal failure.

Contrast Media↗
PubMed2000

The autism diagnostic observation schedule-generic: a standard measure of social and communication deficits associated with the spectrum of autism.

The Autism Diagnostic Observation Schedule-Generic (ADOS-G) is a semistructured, standardized assessment of social interaction, communication, play, and imaginative use of materials for individuals suspected of having autism spectrum disorders. The observational schedule consists of four 30-minute modules, each designed to be administered to different individuals according to their level of expressive language. Psychometric data are presented for 223 children and adults with Autistic Disorder (autism), Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) or nonspectrum diagnoses. Within each module, diagnostic groups were equivalent on expressive language level. Results indicate substantial interrater and test-retest reliability for individual items, excellent interrater reliability within domains and excellent internal consistency. Comparisons of means indicated consistent differentiation of autism and PDDNOS from nonspectrum individuals, with some, but less consistent, differentiation of autism from PDDNOS. A priori operationalization of DSM-IV/ICD-10 criteria, factor analyses, and ROC curves were used to generate diagnostic algorithms with thresholds set for autism and broader autism spectrum/PDD. Algorithm sensitivities and specificities for autism and PDDNOS relative to nonspectrum disorders were excellent, with moderate differentiation of autism from PDDNOS.

Autistic Disorder↗
PubMed1999

The contribution of bone scintigraphy in occupational health or medical insurance claims: a retrospective study.

Patients with a suspicion of bone damage following an industrial or traffic accident are often referred for bone scintigraphy as part of an occupational health or medical insurance investigation. The aim of this study was to assess the contribution and the potential role of bone scintigraphy compared with X-ray investigations in the aforementioned situation. To this end we evaluated 70 consecutive patients referred for bone scintigraphy during 1996 and 1997 by occupational health or medical insurance physicians. The most common reasons for referral were the exclusion of occult fractures of hands and feet, whiplash injuries, reflex sympathetic dystrophy or avascular necrosis, or the differentiation between an old and a recent vertebral fracture. X-rays were only available for comparative review of 53 patients, so only those were analysed. The results of bone scintigraphy were compared with X-rays, and their contribution and potential role in occupational health or medical insurance investigations assessed. In 31 out of the 53 patients investigated, bone scintigraphy findings concurred with X-rays as to the number and location of abnormalities. For 19 of the 53 patients, bone scintigraphy showed clinically relevant additional foci when compared with X-rays, predominantly involving lesions to hands/wrists and feet/ankles. Among these 19 patients, scintigraphic diagnoses were subsequently confirmed in ten cases by means of X-ray or computed tomography. In four patients, supplementary radiological investigations revealed no abnormalities, and in five patients no further investigations were undertaken. Finally, in three of the 53 patients, X-rays revealed bone damage (burst fractures) whilst the corresponding bone scintigraphy was negative, thus excluding recent injury. In conclusion, in 22 patients, representing 42% of the cases analysed, bone scintigraphy was conclusive compared with X-ray imaging in the final diagnosis and in this way in detecting occult or excluding active bone damage after a traffic or industrial accident. This makes bone scintigraphy a useful investigation in situations where a full or partial disablement claim has to be confirmed, extended or terminated.

Accidents, Occupational↗
PubMed1990

Isolation of four forms of acetone-induced cytochrome P-450 in chicken liver by h.p.l.c. and their enzymic characterization.

The purpose of this study was to purify and characterize the forms of cytochrome P-450 induced in chicken liver by acetone or ethanol. Using high performance liquid ion-exchange chromatography, we were able to isolate at least four different forms of cytochrome P-450 which were induced by acetone in chicken liver. All four forms of cytochrome P-450 proved to be distinct proteins, as indicated by their N-terminal amino acid sequences and their reconstituted catalytic activities. Two of these forms, also induced by glutethimide in chicken embryo liver, appeared to be cytochromes P450IIH1 and P450IIH2. Both of these cytochromes P-450 have identical catalytic activities towards benzphetamine demethylation. However, they differ in their abilities to hydroxylate p-nitrophenol and to convert acetaminophen into a metabolite that forms a covalent adduct with glutathione at the 3-position. Another form of cytochrome P-450 induced by acetone is highly active in the hydroxylation of p-nitrophenol and in the conversion of acetaminophen to a reactive metabolite, similar to reactions catalysed by mammalian cytochrome P450IIE. Yet the N-terminal amino acid sequence of this form has only 30-33% similarity with cytochrome P450IIE purified from rat, rabbit and human livers. A fourth form of cytochrome P-450 was identified whose N-terminal amino acid sequence and enzymic activities do not correspond to any mammalian cytochromes P-450 reported to be induced by acetone or ethanol.

Acetaminophen↗
PubMed1990

Hepatic alcohol dehydrogenase activity in chick hepatocytes towards the major alcohols present in commercial alcoholic beverages: comparison with activities in rat and human liver.

We have compared hepatic alcohol dehydrogenase activities in chick, rat and human liver with the major alcohols in commercial alcoholic beverages. 1. Chick and rat hepatic alcohol dehydrogenase was greater when assayed at a physiological pH in buffer containing chloride ions, as compared with the activity in pyrophosphate buffer at alkaline pH. 2. In contrast to reports of instability of ADH to freezing, we found the enzyme from all three species stable to freezing in 0.25 M sucrose. 3. Rat liver enzymatic activity was unstable in the presence of substrate, where as that of chick and human was not. 4. For all three species, the Km of hepatic ADH for substrate decreased with increasing chain length of alcohols. In both chick and human samples, the Vmax values for the higher chain alcohols were similar to that with ethanol, while in rat samples, ADH activity was dramatically lower with the higher chain alcohols compared to ethanol.

1-Propanol↗
PubMed1989

MRI signal intensity profiles of sellar and perisellar lesions.

Literature data are reviewed and cumulated with our own findings in order to delineate the ability of MRI to evaluate the nature of sellar and perisellar lesions by analyzing their signal intensity profiles. The existence of different trends in T1 and T2 relaxation characteristics was documented within a spectrum of frequently presenting lesions. Magnetic resonance imaging (MRI) signal intensity analysis may contribute to exclude differential diagnostic problems remaining after computer tomographic examination of the sella. MRI should be the primary imaging test (in the absence of the known contra-indications) whenever a suspected pituitary or perisellar lesion has to be studied non-invasively.

Adenoma↗
PubMed1988

High field resolution magnetic resonance imaging of malignant choroidal melanoma.

High resolution surface receiver coil nuclear magnetic resonance imaging (MRI) of the eye and paraorbital areas was performed in a patient with a malignant choroidal melanoma before and after local radiotherapy using ruthenium application. The resulting improvement in signal-to-noise ratio allows for a reduction in the imaging voxel size to 0.31 X 0.31 X 3 mm3 which provided useful morphological information with respect to delineation of tumoral mass. In the same MRI session using a standard head coil imaging method, T1 and T2 relaxation time values were calculated in regions of interest of 3 X 3 mm by means of transversal scan images of orbital and cranial tissues performed in scan times of 7 to 9 minutes. The procedure presented here combines in one single session high resolution imaging performance, previously unobservable in MRI and in other noninvasive imaging techniques, with fast and reliable measurement of T1 and T2 relaxation times within small regions of interest. MRI, a non ionizing technique, offers within reasonable acquisition times not only a good multiplanar description of the site, size and volume of normal and pathologic orbital structures, but, in addition, the prospect of soft tissue differentiation and of accurately documenting the response to and side effects of the therapy of ocular tumors.

Choroid Neoplasms↗
PubMed1988

Ultrasonic evaluation of gastric clearing in young infants.

Gastric emptying was determined using ultrasound in young infants. Gastric volume was calculated from anteroposterior, craniocaudal and laterolateral antral diameters. There was a linear decline of the logarithm of a gastric filling index over time in normal subjects. The mean clearing angle in normal subjects was 52 degrees (range 45-59). Examples of significantly different clearing rates could be demonstrated in a variety of clinical conditions. In several subjects gastric emptying rate was not exponential. Ultrasound seems very promising for the study of gastric emptying, especially in young children.

Evaluation Studies as Topic↗
PubMed1988

Single-needle membrane plasmapheresis. In vivo comparison of plasma separator performances.

Plasma filtration characteristics of three hollow fiber plasma separation filters (Plasmaflo Hi-05, Extraplex BL 550 and CPS-10) were studied in a single-needle setting by means of the double headpump. Plasma exchange was carried out in 12 patients during a total number of 59 sessions. For each filter, a mean total ultrafiltration volume of +/- 3,000 ml was obtained over a period from 92 to 121 min. The lowest and highest obtained mean filtration flows were 26.7 +/- 2.5 and 36.6 +/- 1.7 ml/min for Extraplex BL 550 and CPS-10, respectively (p less than 0.01). The pre- and postplasmapheresis pressures, measured in the bubble trap chamber as an indirect estimation of transmembrane pressure, were lower for the Plasmaflo Hi-05 than for the two other filters under study; pressures remained unaltered during the session. Blood pressure showed a minor but significant decline during plasmapheresis with the Plasmaflo filter. A reduction after plasmapheresis by more than 40% of the immunoglobulins IgE, IgG, IgM and IgA, and of complement factors C3 and C4 was seen for each of the filters and no significant differences between the filters were observed. An additional study on 6 filters with constant blood flow and TMP showed minor differences in the transmembrane pressure necessary to obtain a given filtration volume per unit of time and similar sieving coefficients for immunoglobulins. This study demonstrates that with this single-needle technique a satisfying immunoglobulin extraction performance was obtained for each of the filter types studied; however, there existed minor but significant differences in the patient hemodynamic status according to the membrane used.

Blood Pressure↗
PubMed1987

Causes and prognosis of acute renal failure in elderly patients.

In this retrospective study, 287 patients with acute renal failure observed between 1980 and 1985 were divided into 2 groups, according to age: group 1 of 65 years or more (n = 100) and group 2 between 17 and 64 years (n = 187). In both age groups the whole spectrum of causes of acute renal failure was found, but within that spectrum a higher incidence of post-renal failure, acute renal vascular disease and of hypovolaemic acute renal failure was noted in group 1 versus group 2. On the other hand, pigment-induced acute renal failure was lower in group 1 (4%) versus group 2 (13%). The overall survival was 54% in the elderly versus 56% in the younger patients (NS). A close relationship between survival and the number of postadmission complications was found in both groups. Interestingly, the presence of severe hypokalaemia (less than 3.5 mmol/l) and metabolic alkalosis (plasma HCO3 greater than 30 mmol/l) was associated with a very high mortality of 73% and 86% respectively in the elderly patients. Complete or incomplete recovery of renal function was the same in both age groups. It is concluded that age alone should not be used as a discriminating factor in therapeutic decisions concerning acute renal failure in an older patient.

Acute Kidney Injury↗
PubMed1987

Cardiac contusion.

During a consecutive period of 24 months, 244 patients with a major trauma were admitted to the Intensive Care Unit. From this pool of patients 60 consecutively were selected who did fulfill the selected criteria. We intended to determine within this studygroup the incidence, clinical features and outcome of patients with myocardial contusion (MC). We could conclude that no currently used diagnostic test may be seen as an accurate prediction of patients who still develop morbidity or mortality from cardiac contusion. Data from the literature suggest that at present only radionuclide angiography, direct hemodynamic measurement with construction of a Starling curve, and/or 2D-echocardiography may be useful in the identification of the patients at the greatest risk and predictive of the severity of the myocardial injury.

Adult↗