Intertrochanteric corrective osteotomy for moderate and severe chronic slipped capital femoral epiphysis.

A total of 299 acute, acute on chronic, and chronic slips were treated from 1975 to 1997. The patients were reviewed in three cohorts: 75 patients with slipped capital femoral epiphysis (SCFE) were treated between 1975 and 1982, 101 patients with 107 slips were treated from 1983 to 1991, and 110 patients with 117 slips were treated from 1992 to 1997. The authors have corrected 130 hips with chronic slips by intertrochanteric osteotomy. Of these 130 hips, 111 were moderate slips between 20 and 50 degrees, 19 hips with a slipping angle of more than 50 degrees were classified as severe chronic slips. During the same period, 92 chronic slips less than 20 degrees were treated by fixation in situ, and 77 acute or acute on chronic slips had an open and exceptionally a closed reduction followed by fixation. Eight postoperative fractures caused by inadequate plate fixation were observed after these 130 intertrochanteric osteotomies. They all necessitated plate replacement followed by uneventful healing. Three patients with major displacement developed chondrolysis after the corrective osteotomy, two were transient, and one patient developed avascular necrosis (AVN). The midterm clinical results showed a satisfactory outcome in all three cohorts. In 47 patients in the series from 1975 to 1982, the clinical outcome was measured using Imhäuser's score: 43 patients had good and very good results, 4 patients had a moderate or bad result. In the second and third series, the IOWA hip score was used to measure the clinical outcome. The 49 patients with osteotomies for chronic slips treated from 1983 to 1991 had an average score of 90.3 points, and 1 patient had AVN. In the latest series from 1992 to 1997 with 34 corrective osteomies, there was no chondrolysis or AVN and the average IOWA score was 93.9 points.

Side effects of brequinar and brequinar analogues, in combination with cyclosporine, in the rat.

Brequinar is an immunosuppressant with the potential to be combined with cyclosporine in synergistic combination therapy. The drug tends to accumulate when given daily per os, and pharmacokinetic interaction with cyclosporine appears to enhance toxicity. Analogues with similar immunosuppressive activity have been identified at Du Pont Merck Pharmaceutical Co., that do not accumulate upon daily oral dosing in rats, and hence could have an improved potential in combination treatment with cyclosporine. We performed a toxicity study with brequinar and two brequinar analogues, administered orally once daily for 4 weeks, either alone or in combination with cyclosporine (Neoral, Novartis Pharma AG). In a first study relatively high doses were evaluated with cyclosporine at non-toxic doses of 5 and 10 mg/kg/d. The maximum tolerated dose of brequinar alone was estimated between 5 and 10 mg/kg/d; that of the analogues was estimated between 10 and 20 mg/kg/d, and above 20 mg/kg/d, respectively. In combination with cyclosporine at 5 and 10 mg/kg/d, approximately a 2-fold reduction in the maximum tolerated dose was observed. In a second study lower doses were evaluated in combination with cyclosporine at 2.5 and 5 mg/kg/d. Also this study revealed increased toxicity of brequinar (analogues) when given in combination with cyclosporine. The side effects observed were typical for drugs in the brequinar class and included leukocytopenia and thrombocytopenia, reduced body weight gain or body weight loss, thymic atrophy, cellular depletion of bone marrow and splenic white pulp, and villous atrophy in jejunum. Concentrations of brequinar (analogues) were determined in blood sampled 4 h after administration at day 1, 14 and 21-28 of the experiment. There was a tendency for drug accumulation in some groups treated with brequinar and cyclosporine. For one of the analogues at a low dose, higher concentrations were measured in groups treated with combinations of this compound and cyclosporine. We conclude that a potential synergism in immunosuppression using combinations of brequinar (analogues) and cyclosporine can be complicated by enhanced toxicity of the compounds. This indicates the need for a careful evaluation of the therapeutic window in a combined treatment together with detailed pharmacokinetics.

Multiple-dose pharmacokinetics and distribution in tissue of terbinafine and metabolites.

The pharmacokinetics of terbinafine and its inactive metabolites SDZ 86-621 (the N-demethyl form), SDZ 280-027 (the carboxybutyl form), and SDZ 280-047 (N-demethyl- carboxybutyl form) in plasma were characterized for 10 healthy male subjects receiving 250 mg of terbinafine orally once a day for 4 weeks and in the subsequent 8-week washout phase. Terbinafine concentrations were also measured in sebum, hair, nail, and stratum corneum samples. Concentrations of the parent compound and metabolites were determined by validated high-performance liquid chromatography methods. Terbinafine was rapidly absorbed, with peak concentrations in plasma of 1.70 +/- 0.77 micrograms/ml occurring 1.2 +/- 0.3 h postdose. Concentrations subsequently exhibited a triphasic decline, with a terminal deposition half-life of 16.5 +/- 2.8 days. Terbinafine accumulated approximately twofold over the 4-week dosing phase. The predominant metabolite in plasma samples was SDZ 280-027; specifically, the ratios of metabolite area under the curve to terbinafine area under the curve following the last dose were 1.25, 1.38, and 1.08 for metabolites SDZ 86-621, SDZ 280-027, and SDZ 280-047. Measurable concentrations of terbinafine were achieved in sebum and hair samples within the first week of administration and by week 3 in stratum corneum and nail samples. Fungicidal concentrations persisted in plasma and peripheral tissue samples for prolonged periods (weeks to months) after administration of the last dose. These pharmacokinetic properties are likely an underlying factor in the shorter treatment times and good clinical cure rates which have been reported for terbinafine in the therapy of onychomycoses and dermatomycoses.

Simultaneous determination of terbinafine (Lamisil) and five metabolites in human plasma and urine by high-performance liquid chromatography using on-line solid-phase extraction.

The antimycotic agent terbinafine (Lamisil) and five of its main metabolites were determined simultaneously in human plasma and urine samples by an isocratic HPLC method. The compounds were separated on a phenyl column following on-line solid-phase sample clean-up with a column-switching device. Terbinafine and its metabolites were detected by monitoring the column effluent with UV light at a wavelength of 224 nm. The linear range in plasma was assessed between 0 and 2500 ng/ml for the parent drug and metabolites V, IV and I. The linear response of metabolites III and II was assessed between 0 and 1250 ng/ml. In urine, linearity was assessed between 0 and 10,000 ng/ml for metabolites V, IV, III, II and between 0 and 1000 ng/ml for the parent drug and metabolite I. Quantification limits based on a C.V. < or = 20% and a bias < or = +/- 20% ranged from 20 to 500 ng/ml depending on the compound and the matrix. Inter-day and intra-day variations were similar indicating the ruggedness of the two methods. Due to the considerable differences in hydrophobicity between the compounds, extraction efficiencies ranged from 55 to 100%. Both methods were found to be reproducible and sufficiently sensitive for the evaluation of metabolite pharmacokinetics.

Levels of terbinafine in plasma, stratum corneum, dermis-epidermis (without stratum corneum), sebum, hair and nails during and after 250 mg terbinafine orally once daily for 7 and 14 days.

In earlier skin pharmacokinetic studies we have shown that terbinafine is rapidly delivered to the stratum corneum, nails and hair both through sebum and by direct diffusion through dermis-epidermis. In the present study the skin pharmacokinetic profile of terbinafine was studied in two groups of eight human male volunteers during and after 250 mg orally once daily for 7 and 14 days. In the 7-day study high terbinafine levels were found in sebum (19.0 micrograms/g) and stratum corneum (2.5 micrograms/g), and a concentration in stratum corneum above the minimal inhibitory concentration for most dermatophytes was still found 48 days after the last day of medication. Terbinafine was found in peripheral nail clippings after 7 days of medication and the concentration was, in the 7-day study, 0.5 microgram/g 1 day after stopping medication; it was still 0.2 microgram/g 90 days after stopping treatment. The results in the 14-day study were in parallel with, but higher than, in the 7-day study. The elimination of terbinafine from several compartments is biphasic, with a faster initial elimination followed by a slower secondary elimination. For nails, the elimination is slower compared with the other compartments. The results indicate that terbinafine may be effective in short-term treatment of several dermatophytoses. The concentration of 0.2 microgram/g of terbinafine found in nails 90 days after stopping medication, following 7 days of treatment, indicates that the duration of therapy, even in tinea ungium, may be shorter than is currently the case.

Levels of terbinafine in plasma, stratum corneum, dermis-epidermis (without stratum corneum), sebum, hair and nails during and after 250 mg terbinafine orally once per day for four weeks.

The distribution of terbinafine in stratum corneum dermis-epidermis (without stratum corneum), sebum, hair, nails and plasma was studied in human male volunteers during and after 250 mg orally once daily for 28 days. The highest concentration was seen in sebum, 56.07 micrograms/g, after 14 days of therapy. The concentration was still 1.0 microgram/g 44 days after stop of medication. In stratum corneum the highest concentration, 14.4 micrograms/g, was seen 1 day after the last day of therapy, and it was 2.1 micrograms/g 44 days after stop of medication. The concentrations in hair and nails were lower with a maximum of 2.36 and 0.39 micrograms/g respectively, 1 day after stop of therapy, and still 0.21 microgram/g in hair and 0.09 microgram/g in nails 55 days after the last day of medication. With the exception of nails, all other tissue levels were at all times above the plasma concentrations. For nails, tissue levels exceeded that of plasma as early as 1 day after stop of medication, and this difference continued to increase until the last day of tissue sampling, 55 days after the last tablet. These results indicate that terbinafine is delivered to the stratum corneum through sebum and to a minor extent by direct diffusion through dermis-epidermis. Probably short-term therapy with terbinafine may be effective in the treatment of several dermatomycoses, due to the strong binding of terbinafine to stratum corneum for a long time after stop of medication.(ABSTRACT TRUNCATED AT 250 WORDS)

Terbinafine levels in serum, stratum corneum, dermis-epidermis (without stratum corneum), hair, sebum and eccrine sweat.

We determined terbinafine levels in serum, stratum corneum, dermis-epidermis (without stratum corneum), hair, sebum and eccrine sweat before, during and after 250 mg doses orally to volunteers once daily. Terbinafine is concentrated rapidly in stratum corneum (up to 9.1 micrograms/g of tissue) primarily by diffusion from the vascular system through the dermisepidermis. It also reaches high concentration in sebum (up to 45.1 micrograms/ml) after several days and continue to concentrate in sebum for up to two days after discontinuation of drug. Hair concentration reach levels of 2.6 micrograms/g of tissue indicating high drug levels in and around the hair follicle. It is not found in sweat. Plasma levels range between 0.1 and 1.0 micrograms/ml. There is a tenfold accumulation of drug in stratum corneum by day 2. Elimination of drug from tissue occurs with a half-life of 4 to 5 days and with the potential for drug levels above fungicidal concentrations for dermatophytes for more than 3 weeks. The tissue pharmacokinetic profile of terbinafine is similar to that of another lipophilic drug, itraconazole, but is very different from ketoconazole and griseofulvin. Higher levels of terbinafine are achieved than of either of the imidazoles and remain longer than griseofulvin.

Pathophysiological role of thromboxane A2 and pharmacological approaches to its inhibition.

The formation of the proischemic and prothrombotic thromboxane A2 (TXA2) and of its functional antagonist prostacyclin is increased in patients with unstable angina and myocardial infarction. Therefore, pharmacological interventions aim at an inhibition of the synthesis or action of TXA2 without interference with the desirable effects of prostacyclin. Clinical studies currently evaluate low-dose aspirin, thromboxane synthase inhibitors, TXA2/PGH2 receptor antagonists, and a combination of the latter two principles of action. The major advantages and disadvantages of these drugs are: 1. Aspirin irreversibly inhibits TXA2 and PGH2 synthesis in platelets, but also reduces the formation of the platelet-inhibiting PGD2 and prostacyclin--even under a low-dose regimen. 2. Thromboxane synthase inhibitors increase the formation of PGD2 and prostacyclin, but also enhance the accumulation of the potent platelet agonist PGH2. 3. Competitive TXA2/PGH2 receptor antagonists selectively inhibit the action of TXA2 and PGH2 and do not interfere with the eicosanoid metabolism, but their inhibitory effect can be overcome by very high local TXA2 or PGH2 concentrations. 4. Non-competitive TXA2/PGH2 receptor antagonists do not share this drawback. Therefore, they might combine the advantage of aspirin to exert an irreversible inhibition with the specificity of a TXA2/PGH2 receptor antagonist. However, these antagonists are in the stage of experimental studies. 5. The most potent of the clinically available principles of a platelet inhibition is the combination of a thromboxane synthase inhibitor with a competitive TXA2/PGH2 receptor antagonist. Agents that combine both principles of action in one compound are also under clinical investigation.

Irreversible inhibition of the TXA2/PGH2 receptor of human platelets by a photoaffinity ligand.

In order to tag the TXA2/PGH2 receptor of human platelets, we synthesized azido-BSP (= 4-[2-(4-azido-benzenesulfonylamino)-ethyl]phenoxyacetic acid), a photolabile derivative of the specific TXA2/PGH2 receptor antagonist sulotroban (= BM 13.177). If protected from UV light, azido-BSP competitively inhibited the shape change of human washed platelets stimulated by the TXA2 mimetic U 46619. Schild analysis revealed a pA2 = 6.7 (apparent KD = 0.2 mumol/l). Irreversible inhibition of the U 46619-induced platelet activation was achieved by irradiating for 5 min with UV light of 254 nm a platelet suspension containing azido-BSP. After subsequent washing, the platelets were stimulated with U 46619, ADP or PAF. Under these conditions azido-BSP inhibited the shape change, aggregation and [3H]serotonin release induced by U 46619 but not the shape change induced by ADP or PAF. The concentrations of azido-BSP which blocked the U 46619-induced [3H]serotonin release and the aggregation were 0.5 mumol/l and 1.0 mumol/l, respectively, whereas even 50.0 mumol/l of azido-BSP only partially inhibited the U 46619-stimulated shape change. Obviously, increasing numbers of thromboxane receptors have to be blocked in order to inhibit the [3H]serotonin release, the aggregation and the shape change. Even at an azido-BSP concentration equal to 250 times the apparent dissociation constant, enough receptor sites remained active to allow U 46619 to induce the shape change. In sulotroban was added prior to irradiation, the blocking effect of azido-BSP decreased with increasing concentrations of sulotroban. These results show that azido-BSP is a specific and high affinity ligand of the TXA2/PGH2 receptor and that it covalently links to the receptor under irradiation. Azido-BSP is a new tool to identify and characterize the TXA2/PGH2 receptor.

Improved purification of pyruvate decarboxylase from wheat germ. Its partial characterisation and comparison with the yeast enzyme.

An improved procedure was developed for the isolation of pyruvate decarboxylase from wheat germ. Its final step, an electrophoresis of the native apoenzyme in concave pore gradient polyacrylamide gels, followed by superficial activity-staining, produced two bands of different molecular masses and chain compositions. The high-molecular-mass band occurred in low quantity and consisted of, probably eight, apparently identical chains of Mr = 33,000, as judged from sodium dodecyl sulfate electrophoreses. The low-molecular-mass band contained two types of chains with Mr alpha = 63,000-65,000 and Mr beta = 61,000-62,000. The N termini of both chains were threonine, whereas their C-terminal sequences were different: alpha, -(Val)-(Ser)-(Ala)-Leu; beta, -(His)-(Asp)-(Ala)-Ser. Their amino acid composition was too different to be compatible with our original concept of one chain being produced from the other by proteolytic shortening. Limited proteolysis by Staphylococcus aureus V8 proteinase yielded peptides partly identical size and partly quite different. In all properties investigated, the low-molecular-mass enzyme largely resembled yeast pyruvate decarboxylase; the holoenzyme appeared to possess (alpha beta)2 structure, the apoenzyme alpha beta. SH reagents inactivated the enzyme. Binding and fluorescence of 2-p-toluidinonaphthalene-6-sulfonate indicated a similar lipophilicity of the active site as found earlier for the yeast enzyme. 2-Hydroxy-5-nitrobenzyl modification of exposed tryptophan residues left the holoenzyme intact, but in the apoenzyme it destroyed most of the cofactor-binding ability and hence the activity. The strength of cofactor binding and the maximal specific activity were found somewhat lower than in yeast pyruvate decarboxylase.

Activity stain for pyruvate decarboxylase in polyacrylamide gels.

A method for the localization of pyruvate decarboxylase bands in polyacrylamide gels after electrophoresis using 1,2-dianilinoethane in dilute acetic acid as reagent for acetaldehyde formed from pyruvate by the holoenzyme is described. A white condensation product forms in the bands and precipitates within a few minutes. The more or less opaque bands can be viewed and photographed against a dark background and scanned in a densitometer. The detection limit is at about 10 mU pyruvate decarboxylase when the gels are bathed in the staining solution for 20 min. Several other methods were tested and failed to produce satisfactory results.

Characterization of two glyceraldehyde-3-phosphate dehydrogenase isoenzymes from the pentalenolactone producer Streptomyces arenae.

Pentalenolactone (PL) irreversibly inactivates the enzyme glyceraldehyde-3-phosphate dehydrogenase [D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating)] (EC 1.2.1.12) and thus is a potent inhibitor of glycolysis in both procaryotic and eucaryotic cells. We showed that PL-producing strain Streptomyces arenae TU469 contains a PL-insensitive glyceraldehyde-3-phosphate dehydrogenase under conditions of PL production. In complex media no PL production was observed, and a PL-sensitive glyceraldehyde-3-phosphate dehydrogenase, rather than the insensitive enzyme, could be detected. The enzymes had the same substrate specificity but different catalytic and molecular properties. The apparent Km values of the PL-insensitive and PL-sensitive enzymes for glyceraldehyde-3-phosphate were 100 and 250 microM, respectively, and the PL-sensitive enzyme was strongly inhibited by PL under conditions in which the PL-insensitive enzyme was not inhibited. The physical properties of the PL-insensitive enzyme suggest that the protein is an octamer, whereas the PL-sensitive enzyme, like other glyceraldehyde-3-phosphate dehydrogenases, appears to be a tetramer.