A Comparative Study on Desipramine Pharmacokinetics in the Rat Brain after Administration of Desipramine or Imipramine

Chronic intraperitoneal administration of desipramine led to an extensive cumulation of the drug in brain and blood compared with that after a single dose treatment, while chronic treatment with desipramine by the oral route produced a brain concentration comparable with its level after a single oral dose. Comparison of the present results with the corresponding data of published imipramine pharmacokinetics indicated that the cumulation of desipramine in the rat brain was nearly the same when rats received desipramine or imipramine twice a day for two weeks at a dose of 10 mg kg−1 orally, or imipramine, twice a day for two weeks at a dose of 10 mg kg−1 intraperitoneally. It is suggested that these three experimental paradigms may be used as models for differentiation of the pharmacological effects of imipramine and desipramine in-vivo.

Similar effects of nifedipine and hydralazine on anaesthesia and hypermotility induced by pentobarbitone in mice

Nifedipine, a dihydropyridine calcium channel blocker, and hydralazine, a non-calcium channel antagonist vasodilatator, enhanced pentobarbitone-induced sleeping time and reversed locomotor hyperactivity induced by a subhypnotic dose of the barbiturate in mice. The similarity of the behavioural effects, exerted by nifedipine and hydralazine, suggest that haemodynamic factors may play an important role in the interaction of calcium channel antagonists with barbiturates.

Divalproex treatment for youth with explosive temper and mood lability: a double-blind, placebo-controlled crossover design

OBJECTIVE

The authors sought to replicate open-label findings showing that specific criteria for explosive temper and mood lability identify disruptive youth who improve while receiving the anticonvulsant divalproex sodium.

METHOD

Twenty outpatient children and adolescents (ages 10-18) with a disruptive behavior disorder (oppositional defiant disorder or conduct disorder) met the specific criteria for explosive temper and mood lability. They received 6 weeks of divalproex treatment and 6 weeks of placebo by random assignment. Independent evaluators blind to group assignment assessed response at the end of each phase.

RESULTS

At the end of phase 1, eight of 10 subjects had responded to divalproex; zero of 10 had responded to placebo. Of the 15 subjects who completed both phases, 12 has superior response taking divalproex.

CONCLUSIONS

This preliminary study replicates open-label findings showing that divalproex is an efficacious treatment for explosive temper and mood lability in disruptive children and adolescents.

Effect of carbamazepine on the pharmacokinetics of promazine

Combinations of neuroleptics and carbamazepine are administered to psychiatric patients in the therapy of mania, manic-depressive illness and schizophrenia. The present study was aimed at assessing the influence of carbamazepine on the pharmacokinetics of promazine. Male Wistar rats received promazine and/or carbamazepine twice daily for two weeks (promazine, 10 mg/kg ip; carbamazepine, 15 mg/kg ip during the 1st, and 20 mg/kg ip during the 2nd week of treatment). In a short time (1 h) after administration, carbamazepine had a tendency to increase the concentration of promazine in the blood plasma and brain. Lineweaver-Burk's analysis showed that carbamazepine added in vitro competitively inhibited the N-demethylation of promazine in liver microsomes, without affecting the sulphoxidation process. The effect was reflected in vivo (1 h) by an increased promazine/desmethylpromazine ratio. After a long time interval (6 h, 12 h), carbamazepine decreased the concentration of promazine and its metabolites. In vitro studies into the promazine metabolism, conducted on microsomes from rats treated with promazine and/or carbamazepine, did not show acceleration of its demethylation or sulphoxidation by carbamazepine. The obtained results suggest that induction of promazine metabolism by carbamazepine involves metabolic pathways other than N-demethylation or sulphoxidation. It has been concluded that when a phenothiazine neuroleptic, such as promazine, is administered jointly with carbamazepine, a slight increase in the neuroleptic concentration may be expected in a short time after administration, followed by its significant decrease.

Randomized trial of recombinant platelet factor 4 versus protamine for the reversal of heparin anticoagulation in humans

BACKGROUND

Protamine reverses heparin anticoagulation, but it can have important side effects. We compared the safety and effectiveness of intravenous recombinant platelet factor 4 (rPF4) as an alternative to protamine in a randomized blinded trial.

METHODS AND RESULTS

In 81 patients having diagnostic cardiac catheterization, baseline hemodynamics were measured after a 5000-U bolus of heparin. Repeat measurements were obtained at the end of the procedure, and the anticoagulation status was determined by an activated coagulation time (ACT) and activated partial thromboplastin time (aPTT). Patients then received either protamine (50 mg IV over 10 minutes) or rPF4 (1.0 mg/kg IV over 2 minutes) in a blinded fashion. Serial measurements of hemodynamic and clotting functions were performed 5, 10, 20, and 30 minutes after drug administration. Follow-up measurements and clinical assessments were made at 1, 4, 6, and 24 hours later and after 7 days. Before drug administration, ACTs, aPTTs, and hemodynamics were similar among the groups. After drug infusion, there was no difference in ACT between the protamine and rPF4 patients. At 20 and 30 minutes after drug infusion, ACT and aPTT were slightly higher in those receiving rPF4, but these changes were small and of no clinical significance. There were no clinically meaningful differences in any of the hemodynamic variables between the groups, and there were no serious side effects in any patient.

CONCLUSIONS

At the dose used in this study, rPF4 was well tolerated and reversed the anticoagulant effect of heparin. These data support its continued evaluation as an alternative to protamine after cardiac surgery.

Estimating underreported pesticide poisonings in Nicaragua

We undertook to estimate the degree of underreporting to a regional pesticide poisoning registry, and to estimate the true incidence of poisoning in an agricultural region of Nicaragua. We surveyed 633 workers at 25 of 33 agricultural cooperatives and any nearby private forms in a area geographically convenient to the regional health headquarters with a short structured interview about pesticide poisonings. Eighty-three percent of workers described current use of pesticides. Twenty-five percent described a pesticide poisoning in the preceding 12 months, and almost one-half (48%) described having been made ill by pesticides at some point in time. Sixty-nine (11%) described a poisoning in the preceding month, 23 of whom had received medical attention. The names of the medically treated were sought in the Regional Pesticide Poisoning Registry for the survey year of 1988. Only 8 of the 23 subjects were found reported to the registry when a total of 1,143 human pesticide poisonings were reported in the entire region. Using 65% as an estimate of underreporting to the registry, we calculate that 3,300 (95% CI 2100-7500) poisonings had received treatment in the region in 1988, of whom more than 2,100 remained unreported. Based on the ratio of total poisonings (treated and untreated) to registry-reported poisonings among our survey respondents, we estimate that 6,700 (95% CI 4100-18000) systemic poisonings, occurred in 1988 in the region. Underreporting of pesticide poisonings disguises the enormity of the problem in developing countries. Even in a region with a strong emphasis on illness reporting for targeted conditions, underreporting is substantial. This method for estimating underreporting is easily applied and provides a rough estimate of registry underreporting and actual incidence for conditions identifiable by a community-applied questionnaire.

Causes of haloperidol discontinuation in patients with Tourette's disorder: management and alternatives

BACKGROUND

Neuroleptics are considered the mainstay of treatment in Tourette's disorder, and haloperidol is deemed the treatment of choice by many. Factors such as treatment efficacy and the side effects that appear in response to neuroleptic administration have been implicated in affecting medication compliance. However, a detailed evaluation of these factors has yet to be undertaken in Tourette's disorder.

METHOD

Of 51 consecutive referrals to a Tourette's disorder clinic, 48 met DSM-III-R criteria for Tourette's disorder. Of these 48, 28 had previously received neuroleptics. In this set of 28 patients, 24 (16 male, 8 female) had initially received treatment with haloperidol, and they made up the present sample; their ages ranged from 10.4 to 47.9 years (mean = 27.1), and age at onset ranged from 2 to 16 years. Each patient completed an evaluation consisting of a Tourette Syndrome Questionnaire and a clinical interview with the patient and involoved family members. Charts were also reviewed to gather information concerning side effects and other factors that led to haloperidol discontinuation and/or noncompliance.

RESULTS

Duration of treatment ranged from 3 days to 14 years (mean = 3.6 years). In this sample, 12.5% (3/24) of the subjects continued medication without interruption (mean +/- SD = 8.4 +/- 5.1 years of medication). Of the 21 patients who discontinued haloperidol, 66.7% (14/21) did so because they experienced intolerable side effects, 9.5% (2/21) because of the fear of experiencing certain side effects, and 14.3% (3/21) because of a combination of these factors. The principal side effects that led to discontinuation included dysphoric reactions, akathisia, nervousness, sedation, dystonic reactions, and cognitive dulling/feeling drugged.

CONCLUSION

Careful monitoring of side effects and efficacy is essential to continued compliance with haloperidol. In addition, psychoeducation about potential consequences of medication administration may help promote compliance in those patients who develop fears of possible adverse reactions.

Metabolism of psychotropic drugs: pharmacological and clinical relevance

Cytochrome P-450 (CYP) catalyzes phase I metabolic reactions of psychotropic drugs. The main isoenzymes responsible for their biotransformation are CYP1A2, CYP2D6, CYP3A4 and these of the subfamily CYP2C. The majority of metabolites of psychotropic drugs are biologically active. Some of them retain pharmacological properties of parent compounds (eg. selective serotonin reuptake inhibitors, risperidone, carbamazepine, benzodiazepines), but others display quite different (eg. amitriptyline, buspirone) or even opposite (trazodone) profiles. They are present in vivo in concentrations high enough to contribute to pharmacological and clinical effects of the administrated drugs. Active metabolites of psychotropics are also characterized by pharmacokinetic properties different from their parent compounds, e.g. half-life time, plasma protein binding, blood-brain-barrier penetration, the cerebrospinal fluid (CSF) protein binding and tissue binding. These properties lead, in turn, to differences in the brain/plasma and the CSF/plasma concentration ratios between a drug and its metabolites. Therefore studies relating a pharmacological or therapeutic response of psychotropic drug to its plasma concentrations should not disregard the presence of its active metabolites, considering their distinct pharmacological and pharmacokinetic properties. With regard to a low therapeutic index of psychotropics, interindividual differences in the rate of their metabolism, genetic polymorphism of their main metabolic pathways and metabolic interactions in clinical drug combinations, the phenotyping of patients at the beginning of therapy and a control of drug concentrations (and its active metabolites) at a steady state and during coadministration of another drug, may increase the efficiency and safety of the pharmacotherapy of psychiatric disorders.

The pharmacokinetics of promazine and its metabolites after acute and chronic administration to rats--a comparison with the pharmacokinetics of imipramine

This study was aimed to investigate the pharmacokinetics of promazine (a phenothiazine analogue of imipramine) after its single and repeated administration. Male Wistar rats received promazine as a single injection (10 mg/kg ip) or they were treated chronically with the neuroleptic, once a day for two weeks. Plasma and brain concentration of promazine, desmethylpromazine and promazine sulphoxide were determined using the HPLC method devised by us. The results of the present study were compared with our earlier data obtained in analogous experiments with imipramine. The obtained data showed that the pharmacokinetics of promazine and imipramine was similar, though certain differences could be noticed. Both those drugs were unevenly distributed throughout the body, occurring in low concentrations in the blood plasma and reaching considerably higher concentrations in the brain. However, the uptake of promazine by the brain was more efficient than that of imipramine. The brain/plasma AUC ratio after a single dose amounted to 28.72 for promazine and 12.78 for imipramine. Their demethylated metabolites behaved in a similar way, where as the level of promazine sulphoxide in the brain was three times lower than that in the plasma. Chronic treatment with promazine or imipramine increased concentrations of the parent compounds and their demethylated metabolites, and prolonged their half-life in the plasma and brain. The plasma level of promazine sulphoxide did not change, and its brain level was decreased by chronic treatment with promazine. The half-life of promazine sulphoxide was prolonged in the plasma but shortened in the brain after repeated administration of promazine. The observed considerable amounts of desmethylpromazine and promazine sulphoxide, formed in vivo, suggest that the two compounds are major metabolites of promazine, and that the metabolic pattern of promazine in the rat and man is similar.

[Unilateral left superior vena cava in absent right superior vena cava. Modern imaging diagnosis and clinical relevance]

Cardiological and radiological findings in a 64-year-old patient with persistent left superior vena cava and absent right-sided superior vena cava are described. Presence of a persistent left superior vena cava (PLSVC) is considered to be one of the most frequent anomalies of the systemic venous return. It occurs most often in association with a right-sided superior vena cava and only in rare cases with an absent or atretic right-sided superior vena cava. This malformation is often associated with other congenital heart defects, but without major hemodynamic significance. The variation may cause difficulties in venous catheterization, pacemaker electrode insertion or during cardiopulmonary bypass. The diagnosis can be confirmed by angiography, computed tomography and nuclear magnetic resonance imaging.

Effect of medical and surgical therapy on aortic dissection evaluated by transesophageal echocardiography. Implications for prognosis and therapy. The European Cooperative Study Group on Echocardiography

BACKGROUND

Aortic dissection still has a poor prognosis despite progress in therapy. Therefore, this prospective follow-up study was designed to determine whether the degree of communication between true and false lumen in relation to the type of dissection, analyzed by transesophageal echocardiography, influences the risk after initiation of medical or surgical therapy.

METHODS AND RESULTS

In eight centers, 168 patients (124 men and 44 women) of age range of 23-84 years with proven aortic dissection were examined by transesophageal echocardiography in the acute phase, after start of medical and/or surgical therapy, and during follow-up (0-65 months; mean, 10 months). Analyses were performed prospectively according to a detailed study protocol. Patients were subdivided by transesophageal echocardiography according to a modified DeBakey classification. Type I aortic dissection was found in 35%, type II aortic dissection in 17%, and type III aortic dissection in 48%. Preoperative mortality was 3%, 7%, and 2%, and survival rates were 52%, 69%, and 70%, respectively. Type III aortic dissection could be subdivided into those with communication and antegrade dissection (ca) (50%), with communication and retrograde dissection limited to the descending aorta (cr desc) (10%), with dissection extended to the aortic arch and ascending aorta (cr asc) (27%), and with noncommunicating (nc) aortic dissection (13%). An open false lumen with no thrombus formation was present in types I, II, III ca and III cr asc aortic dissection in 17%, 21%, 39%, and 27% respectively, although it was most pronounced in types III nc and III cr desc (75% and 78%). During follow-up in patients who survived, thrombus was demonstrated in the false lumen in 80% of type I aortic dissection and 81% of types III ca and III cr asc. Open false lumen was seen in type II aortic dissection in 18%. Spontaneous healing was found in 4% with type II and 4% with type III aortic dissection (mainly in patients with type III nc aortic dissection). Patients with fluid extravasation, pleural effusion, pericardial tamponade, and periaortic effusion as well as mediastinal hematoma had a mortality of 52%. Reoperations were necessary in 12-29%, with the highest rate in patients with type III ca aortic dissection. Survival for patients with types III nc and III cr desc aortic dissection was higher than those with types I, II, III ca, and III cr asc.

CONCLUSIONS

Preoperative mortality appears to be reduced by transesophageal echocardiography, allowing rapid initiation of treatment. Intraoperative and postoperative mortality in aortic dissection remains high. Risk factors are fluid extravasation and an open false lumen with high communication. Thrombus formation in the false lumen can be regarded as a good prognostic sign. Surgery appears to be only a first step in the treatment of aortic dissection. Second surgery or closure of entry sites based on intraoperative echocardiography may be considered to induce thrombus formation and reduce aortic wall stress.

Pharmacokinetic interaction between carbamazepine and neuroleptics after combined prolonged treatment in rats

This study investigates how neuroleptics of phenothiazine or thioxanthene structure influence the pharmacokinetics of carbamazepine. Experiments were carried out on male Wistar rats. Carbamazepine and the neuroleptics were administered i.p., separately or together, for 2 weeks in the following daily doses (mg/kg): carbamazepine 15 during the 1st week of treatment and 20 during the 2nd week of treatment, promazine 10, chlorpromazine 2, perazine 10, chlorprothixene 2, flupenthixol 0.5. One hour after the last injection of carbamazepine and/or the neuroleptic, samples of blood plasma and brain were taken to determine the concentrations of carbamazepine and two of its metabolites: 10,11-epoxide and trans-10,11-diol. The neuroleptics increased the concentration of carbamazepine in plasma and in brain, but tended to decrease (with the exception of chlorpromazine) the concentration of the epoxide and increased the concentration of trans-10,11-diol. Metabolic in vitro studies did not show any significant differences between rats treated with carbamazepine alone and those treated with carbamazepine plus neuroleptic in the rates of the carbamazepine epoxidation, of 10,11-epoxide hydrolysis or of 1-naphthol glucuronidation.

Pseudocolor displays in B-mode imaging applied to echocardiography and vascular imaging: an update

Cardiac and vascular ultrasound systems incorporting colorized gray-scale display options to supplement the standard B-mode gray-scale image have recently reappeared on the market from several manufacturers. As yet, the clinical benefit of this "new" technology is unknown, and recommendations and protocols for its best application are not available. This article reviews the limitations of the gray-scale displays currently used, the rationale of the color-supplemented B-mode image, and some of the potential applications to cardiac and vascular ultrasound.

Management of thoracoabdominal malperfusion in aortic dissection

Malperfusion of the thoracoabdominal aorta or its branches is a common complication of aortic dissection, often with a fatal outcome. Since 1985 we saw thoracoabdominal malperfusion in 13 patients with aortic dissection. During repair of an acute type A aortic dissection, the intimal flap was fenestrated in three cases in the abdominal aorta and one within the superior mesenteric artery. In two cases with acute type B aortic dissection fenestration was performed at the level of the aortic bifurcation, and in one the descending aorta was replaced. Six patients had chronic dilatation of a false lumen without distal reentry, compromising the true lumen, with malperfusion of viscera, kidneys, and lower extremities. Three patients underwent replacement of the descending aorta, two of them subsequent abdominal aortic replacement with revascularization of the kidneys. One patient had thoracoabdominal replacement, and in two an extra-anatomic bypass was implanted. Five patients with acute dissection died: two from sequelae of malperfusion, two of myocardial failure, and one late after stroke. Eight patients are alive 1 month to 5 years after operation. In acute aortic dissection fenestration of the intimal flap may relieve thoracoabdominal malperfusion. In chronic aortic dissection, pseudocoarctation is most likely to occur at the diaphragmatic hiatus. This is treated by replacement of the affected aortic segment. In high-risk patients an extra-anatomic bypass is also feasible.

Pharmacokinetic interaction between imipramine and antidepressant neuroleptics in rats

Antidepressant neuroleptics, perazine (PZ), levomepromazine (LMZ) and flupenthixol (FPX) given to rats jointly with imipramine (IMI) for 2 weeks affected the plasma concentration of IMI only slightly but markedly elevated the concentration of its metabolite, desipramine (DMI). In the brain PZ significantly elevated both IMI and DMI concentrations while LMZ and FPX showed a tendency to increase the concentration of IMI and decrease the concentration of DMI. All three neuroleptics markedly decreased the DMI/IMI ratio in the brain and (except FPX) increased it in the plasma. Given alone for two weeks PZ, LMZ, FPX did not affect the levels of cytochromes P-450 and b-5 in liver microsomes. Chronic treatment with IMI significantly elevated the concentration of cytochrome P-450 in the liver and had a tendency to increase the concentration of cytochrome b-5. FPX, but not PZ or LMZ abolished this effect. Neuroleptics coadministered with IMI to rats did not affect the activity of the enzymes responsible for the IMI biotransformation as compared with IMI-treated animals. The neuroleptics added to the incubation mixture in vitro inhibited IMI hydroxylation noncompetitively. The demethylation was inhibited competitively by LMZ but noncompetitively by PZ and FPX. The inhibitory effect of neuroleptics on the hydroxylation was much more marked than that on the demethylation. FPX was the weakest inhibitor of IMI metabolism among the neuroleptics studied.

The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hip

Clinical criteria for the classification of patients with hip pain associated with osteoarthritis (OA) were developed through a multicenter study. Data from 201 patients who had experienced hip pain for most days of the prior month were analyzed. The comparison group of patients had other causes of hip pain, such as rheumatoid arthritis or spondylarthropathy. Variables from the medical history, physical examination, laboratory tests, and radiographs were used to develop different sets of criteria to serve different investigative purposes. Multivariate methods included the traditional "number of criteria present" format and "classification tree" techniques. Clinical criteria: A classification tree was developed, without radiographs, for clinical and laboratory criteria or for clinical criteria alone. A patient was classified as having hip OA if pain was present in combination with either 1) hip internal rotation greater than or equal to 15 degrees, pain present on internal rotation of the hip, morning stiffness of the hip for less than or equal to 60 minutes, and age greater than 50 years, or 2) hip internal rotation less than 15 degrees and an erythrocyte sedimentation rate (ESR) less than or equal to 45 mm/hour; if no ESR was obtained, hip flexion less than or equal to 115 degrees was substituted (sensitivity 86%; specificity 75%). Clinical plus radiographic criteria: The traditional format combined pain with at least 2 of the following 3 criteria: osteophytes (femoral or acetabular), joint space narrowing (superior, axial, and/or medial), and ESR less than 20 mm/hour (sensitivity 89%; specificity 91%). The radiographic presence of osteophytes best separated OA patients and controls by the classification tree method (sensitivity 89%; specificity 91%). The "number of criteria present" format yielded criteria and levels of sensitivity and specificity similar to those of the classification tree for the combined clinical and radiographic criteria set. For the clinical criteria set, the classification tree provided much greater specificity. The value of the radiographic presence of an osteophyte in separating patients with OA of the hip from those with hip pain of other causes is emphasized.

Regional distribution of imipramine, desipramine and specific [3H]desipramine binding sites in the rat brain after acute and chronic treatment with imipramine

Regional distribution of imipramine, desipramine and specific [3H]desipramine binding sites in the rat brain after acute and chronic treatment of rats with imipramine has been investigated. Both substances were distributed unevenly within rat brain after single and prolonged administration of imipramine. This was partly connected with the regional cerebral blood flow, lipid content in the regions and lipophilicity of the substances investigated. It was also found that the number of specific [3H]desipramine binding sites was different in the various brain areas, and that prolonged administration of imipramine led to a decrease of their number in some of those regions. No correlation was found between the regional cerebral distribution of desipramine and the regional density of specific [3H]desipramine binding sites.

The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hand

Clinical criteria for the classification of symptomatic idiopathic (primary) osteoarthritis (OA) of the hands were developed from data collected in a multicenter study. Patients with OA were compared with a group of patients who had hand symptoms from other causes, such as rheumatoid arthritis and the spondylarthropathies. Variables from the medical history, physical examination, laboratory tests, and radiographs were analyzed. All patients had pain, aching, or stiffness in the hands. Patients were classified as having clinical OA if on examination there was hard tissue enlargement involving at least 2 of 10 selected joints, swelling of fewer than 3 metacarpophalangeal joints, and hard tissue enlargement of at least 2 distal interphalangeal (DIP) joints. If the patient had fewer than 2 enlarged DIP joints, then deformity of at least 1 of the 10 selected joints was necessary in order to classify the symptoms as being due to OA. The 10 selected joints were the second and third DIP, the second and third proximal interphalangeal, and the trapeziometacarpal (base of the thumb) joints of both hands. Criteria derived using the "classification tree" method were 92% sensitive and 98% specific. The "traditional format" classification method required that at least 3 of these 4 criteria be present to classify a patient as having OA of the hand. The latter sensitivity was 94% and the specificity was 87%. Radiography was of less value than clinical examination in the classification of symptomatic OA of the hands.

Cerebral pharmacokinetics of ipsapirone in rats after different routes of administration

Ipsapirone, a putative non-benzodiazepine anxiolytic, was extensively metabolized in rats to 1-(2-pyrimidinyl)piperazine (1-PP) which accumulated in the brain. Neither the route of administration (i.p. or p.o.), nor prolonged administration of ipsapirone or 1-PP affected their accumulation in the rat brain. The cytochrome P450 level and ethylmorphine N-demethylase activity in rat liver microsomes were unchanged by chronic treatment with ipsapirone or 1-PP. The results indicate that 1-PP may contribute to the alpha 2-adrenoceptor antagonism of ipsapirone in rats and that chronic treatment with the drug does not affect its biotransformation to 1-PP.

Alteration of cytochrome P-450 by prolonged administration of imipramine and/or lithium to rats

The aim of this study was to investigate imipramine-induced alterations of cytochrome P-450 and to determine whether prolonged concomitant administration of imipramine and lithium results in a pharmacokinetic interaction. Male Wistar rats received imipramine (10 mg/kg i.p.) at 12 h intervals or lithium chloride (100 mg/kg in drinking water) or they were treated with the combination of these drugs for 2 weeks. The long term treatment with imipramine produced a very complex alteration of cytochrome P-450: imipramine increased the level of the cytochrome, but it decreased the rate of its own aromatic hydroxylation in position 2. The rate of N-demethylation in the side chain was not changed. Consequently, in the case of both hydroxylation and demethylation, calculated molecular activities were decreased to 48% and 70% respectively. This differential change in activities corresponded well to the observed decrease of absorption in difference spectra (type I) produced in microsomes by imipramine. Carbamazepine-induced type I difference spectra were also decreased by imipramine pretreatment, but to a lesser extent. In contrast, hexobarbital type I binding was increased by imipramine treatment while type II difference spectra produced by metyrapone were not affected. The preliminary SDS-PAGE analysis of cytochrome P-450 isoenzymes of control and imipramine treated rats showed that the investigated antidepressant markedly intensified a protein band at 50.11 kD while bands at 51.28 kD, 56.20 kD and 56.88 kD were less intensive. These results indicate that the alteration of cytochrome P-450 by imipramine treatment is not only of quantitative but also of qualitative character. Lithium alone given to rats affected neither the concentration of cytochrome P-450 in microsomal protein nor the rate of imipramine metabolism in vitro. Lithium given jointly with imipramine reduced imipramine-induced elevation of cytochrome P-450.(ABSTRACT TRUNCATED AT 250 WORDS)

Diastolic dysfunction during acute cardiac allograft rejection

Left ventricular diastolic function was evaluated in 41 heart transplant patients during acute rejection by an analysis of echocardiograms and surgically implanted intramyocardial tantalum markers. In 35 patients, isovolumic relaxation time was calculated from M-mode tracings selected from two-dimensional echocardiographic recordings. A total of 84 biopsy findings of no rejection, moderate rejection, and severe acute rejection after treatment were correlated with measurements of isovolumic relaxation time. In six patients, end-diastolic volume, end-systolic volume, stroke volume, ejection fraction, and peak filling rate were obtained from biplanar cineradiographic images of intramyocardial markers. Data from 11 prerejection periods were compared with those of moderate acute rejection. All echocardiograms and marker images were analyzed without previous knowledge of biopsy findings. At times of acute rejection, isovolumic relaxation time decreased from 107 to 65 msec (p less than 0.01) and returned to 98 msec after immunosuppressive therapy. Ejection fraction and end-systolic volume did not change significantly with acute rejection, whereas stroke volume decreased from 76 to 67 ml (p less than 0.05). In contrast to the effects on systolic function, episodes of acute rejection were accompanied by a decrease in end-diastolic volume from 166 to 153 ml (p less than 0.01) and a reduction in peak filling rate from 514 to 460 ml/sec (p less than 0.05). These data suggest that acute cardiac rejection is associated with relative preservation of left ventricular systolic performance but with alterations in diastolic dynamics similar to those seen in "restrictive" cardiomyopathy.

Echocardiography in diagnosis of aortic dissection

In a multicentre study the accuracy of echocardiography was measured in 164 consecutive patients with suspected aortic dissection. The diagnosis was subsequently proven (82 patients) on the basis of transthoracic and transoesophageal echocardiography and additional diagnostic procedures, including computed tomography (CT), aortic angiography, and surgery and/or necropsy. The sensitivity and specificity of echocardiography were 99% and 98%, respectively, with positive and negative predictive values of 98% and 99%. For CT sensitivity was 83%, specificity 100%, and positive and negative predictive values 100% and 86%, respectively. For aortography sensitivity and specificity were 88% and 94%, and the positive and negative predictive values 96% and 84%, respectively. Echocardiography, including the transoesophageal route, can provide accurate diagnosis of aortic dissection within 15 min. Diagnostic difficulties occur only in a few type II dissections, when complementary diagnostic procedures, including CT or angiography, may be needed. To clarify branch involvement angiography is required.

Metabolic interaction between imipramine and carbamazepine in vivo and in vitro in rats

The pharmacokinetic consequences of the combination of carbamazepine with imipramine in male Wistar rats have been investigated. It was found that a 2-week treatment with the combination resulted in the increase of the concentrations of the parent compounds and a simultaneous decrease in their metabolites in blood plasma i.e. carbamazepine inhibited imipramine demethylation in the side chain while imipramine inhibited carbamazepine 10,11-epoxidation. The velocity of imipramine 2-hydroxylation and 10,11-epoxy-carbamazepine hydration did not seem to be changed by the combination. On the basis of studies in vitro it is concluded that the observed metabolic interaction between carbamazepine and imipramine is due to the competition of the drugs for the active centre of cytochrome P 450 and to a certain qualitative alteration of the enzyme by imipramine as can be deducted from the decrease of carbamazepine binding to the cytochrome.

A three-year prospective study of systemic manifestation in rheumatoid arthritis

Rheumatoid arthritis (RA) as a systemic disease can attack many other organs in addition to the joints. A variety of pathological lesions of the blood vessels are responsible for the extra-articular features (EAF). In the present study, we investigated firstly whether the presence of blood vessel changes in one organ--namely the skin--may indicate blood vessel pathology and, consequently, EAF in other organs. Secondly, we investigated the number of EAF in individual patients with RA, and observed whether this changed during the course of the disease. Fifty-one RA-patients (40 female, 11 male; ages had a mean of 49.5, minimum 19, maximum 73 years; mean duration of RA was 7.3, minimum 0.25, maximum 41 years) were included in the study. Punch biopsies from the posterior calf were examined immunohistologically for vessel wall immune deposits. Further, EAF were determined by means of instrumental clinical methods such as pulmonary function test, echocardiography, electromyography, and nerve conduction velocity measurement. At the first investigation 21/51 patients had skin vessel wall immune deposits (SVWID). Five patients--all showed SVWID at first investigation--died during the three-year investigation period, 10 patients could not be followed-up for unknown reasons; the skin biopsy of one patient could not be assessed. At the final investigation, we found SVWID in 11/35 patients. SVWID-positive patients had more EAF compared to SVWID-negative patients; this was true both, at the first investigation (1.85 EAF/patient vs 1.05 EAF/patient) and at the final investigation (1.91 EAF/patient vs 0.67 EAF/patient).(ABSTRACT TRUNCATED AT 250 WORDS)

[Change in the diameter of the coronary vessels following sublingual or intravenous nifedipine administration correlated with the plasma level]

The diameter changes of angiographically normal epicardial coronary arteries were studied in 25 patients in correlation to nifedipine plasma levels. In group 1 (15 patients) 20 mg of s.l. nifedipine were administered. Measurements of the coronary lumen size (automated contour detection system, accuracy 0.12 mm) and detection of plasma levels (gas-chromatography) were done before and 10, 20 and 30 min after drug administration. According to the slope of nifedipine plasma levels, patients were divided into group 1 A (n = 4) and 1 B (n = 11). Plasma levels in both groups were: at 10 min, 27.8 +/- 9.8 and 13.5 +/- 4.5 ng/ml resp.; P less than 0.05; at 20 min, 54.0 +/- 11.7 and 21.7 +/- 6.6 ng/ml resp.; P less than 0.001; at 30 min, 79.1 +/- 9.3 and 28 +/- 9.8 ng/ml resp.; P less than 0.001. The corresponding diameter changes in A and B were: 7.3 +/- 5.1%/.-5.6 +/- 9.0% resp.; P less than 0.01; 11.4 +/- 4.1% and -4.5 +/- 11.3% resp.; P less than 0.01; 14.5 +/- 5.9% and 0.5 +/- 13.6% resp.; P less than 0.05. In group 2 (10 patients) 1 mg nifedipine was administered intravenously within 4 min. Measurements were done at 1 min intervals during infusion as well as 7 and 15 min after beginning and compared to a placebo group (n = 10). Peak plasma levels amounted to 16.7 +/- 5.7 ng/ml after 7 min. The maximum coronary dilation was reached after 4 min (verum 5.0 +/- 6.8%; placebo 3.2 +/- 3.6%). Significant differences between both groups were observed after 7 min (verum 4.1 +/- 5.3%; placebo -3.1 +/- 5.8%, P less than 0.05) and 15 min (verum 1.2 +/- 3.2%; placebo -6.2 +/- 8.4%; P less than 0.05).

CONCLUSION

based on significantly different plasma levels following sublingual application of 20 mg nifedipine a classification of patients into "early-" and "late-coronary-responders" could be established. After intravenous infusion of 1 mg nifedipine peak plasma levels were much lower than after sublingual application of 20 mg and coronary diameters showed only a mild increase.