[Significance of hepatic cytochrome P450 enzymes for psychopharmacology]

Nearly all psychotropic drugs are metabolized by hepatic cytochrome P450-enzymes. In humans, there are 5 isoenzymes involved in this process. The activity of these enzymes can be modulated by a number of commonly used drugs, yielding potentially hazardous interactions. Most of the recently introduced selective serotonin reuptake inhibitors are potent inhibitors of cytochrome P450 enzymes. Thus, the plasma concentrations of tricyclic antidepressants or clozapine might be elevated into toxic levels. In contrast, carbamazepine induces most of the isoenzymes. This potentiates the elimination of tricyclics and antipsychotics and might cause a serious risk for the recurrence of depressive or psychotic symptoms. Moreover, 5-10% of the population are slow metabolizers of CYP2D6. This group is prone to increased adverse effects of moderately dosed medication. This review systematically points out the reported or predicted pharmacokinetic drug interactions in psychopharmacology focussing on clinical significance.

[Resistance of bovine and porcine Pasteurella to florfenicol and other antibiotics]

The resistance pattern of 221 (89 bovine, 132 porcine) pasteurella strains isolated in 1996 against 16 antibiotics or chemotherapeutics was determined by agar diffusion. Pasteurella haemolytica showed a higher level of resistance compared to Pasteurella multocida; porcine strains were more resistant than bovine strains. Over 90% of porcine Pasteurella multocida were sensible to penicillin G, ampicillin, cephalothin, polymyxin B, enrofloxacin, chloramphenicol and florfenicol. In addition, bovine strains were at least 90% sensible to oxacillin, erythromycin, gentamycin and sulfmethoxazole-trimethoprim. More than 90% of porcine Pasteurella haemolytica were classified as sensible to polymyxin B, enrofloxacin und florfenicol; bovine strains to cephalothin, neomycin und chloramphenicol as well. In 1996, 2 years after the chloramphenicol ban for food rendering animals, only 6.3% of bovine pasteurella strains proved to be resistant against chloramphenicol compared to a 16.27% fraction in 1994. The mean MIC-values of florfenicol against pasteurella spp. were nearly the same in bovine and porcine isolates with 0.53 microgram/ml and 0.52 microgram/ml respectively. Pasteurella haemolytica, however, showed higher MIC-values (0.68 microgram/ml in bovine, 0.70 microgram/ml in porcine isolates) than Pasteurella multocida with 0.47 microgram/ml in bovine and 0.51 microgram/ml in porcine strains. No isolate had a MIC of florfenicol greater than 1.0 microgram/ml, all pasteurella strains were classified sensible to florfenicol.

The importance of fiber biopersistence and lung dose in determining the chronic inhalation effects of X607, RCF1, and chrysotile asbestos in rats

The chronic inhalation effects in rats of X607 (a rapidly dissolving synthetic vitreous fiber) were compared with those previously reported for RCF1 (a refractory ceramic synthetic vitreous fiber) and chrysotile asbestos. Of primary concern was the importance of biopersistence as a mechanism of fiber toxicity. Fischer rats were exposed to fiber aerosol by nose-only inhalation for 6 h/day, 5 days/week for 2 years. X607 and RCF1 aerosols were similar in concentration (approximately 200 fibers/cc) and average dimensions (approximately 20 x 1 microns). Chrysotile aerosol was higher in concentration (10,600 fibers/cc) and an order of magnitude smaller in average dimensions. Lung fiber deposition after 6 h inhalation was greater for X607 than for RCF1. However, at later time points, fibers/lung (especially long fibers) were much lower for X607 than for RCF1, suggesting less biopersistence for X607. X607 was neither fibrogenic nor tumorigenic and induced only minimal lung cellularity that reversed after exposure was terminated. In contrast, RCF1 and chrysotile asbestos induced pulmonary fibrosis and thoracic neoplasms (chrysotile induced 32% more pulmonary neoplasms than RCF1). Lung deposition and fiber lengths did not explain the toxicologic differences between the three fibers. Fiber biodurability, including chemical and physical parameters, appears to be a major toxicologic determinant here. Chemical analysis of lung fibers revealed rapid leaching of X607 compared to RCF1. In in vitro dissolution tests, X607 underwent rapid dissolution (kdis = 990 ng/cm2/h) and transverse fragmentation, RCF1 dissolved slowly (kdis = 6 ng/cm2/h) and did not fragment, and chrysotile dissolution was negligible (< 0.1 ng/cm2/h).

Physiological characterisation of a pyruvate-carboxylase-negative Saccharomyces cerevisiae mutant in batch and chemostat cultures

A prototrophic pyruvate-carboxylase-negative (Pyc-) mutant was constructed by deleting the PYC1 and PYC2 genes in a CEN.PK strain of Saccharomyces cerevisiae. Its maximum specific growth rate on ethanol was identical to that of the isogenic wild type but it was unable to grow in batch cultures in glucose-ammonia media. Consistent with earlier reports, growth on glucose could be restored by supplying aspartate as a sole nitrogen source. Ethanol could not replace aspartate as a source of oxaloacetate in batch cultures. To investigate whether alleviation of glucose repression allowed expression of alternative pathways for oxaloacetate synthesis, the Pyc- strain and an isogenic wild-type strain were grown in aerobic carbon-limited chemostat cultures at a dilution rate of 0.10 h-1 on mixtures of glucose and ethanol. In such mixed-substrate chemostat cultures of the Pyc- strain, steady-state growth could only be obtained when ethanol contributed 30% or more of the substrate carbon in the feed. Attempts to further decrease the ethanol content of the feed invariably resulted in washout. In Pyc- as well as in wild-type cultures, levels of isocitrate lyase, malate synthase and phospho-enol-pyruvate carboxykinase in cell extracts decreased with a decreasing ethanol content in the feed. Nevertheless, at the lowest ethanol fraction that supported growth of the Pyc- mutant, activities of the glyoxylate cycle enzymes in cell extracts were still sufficient to meet the requirement for C4-compounds in biomass synthesis. This suggests that factors other than glucose repression of alternative routes for oxaloacetate synthesis prevent growth of Pyc- mutants on glucose.

Ventricular arrhythmia and torsade de pointe: dose limiting toxicities of the MDR-modulator S9788 in a phase I trial

BACKGROUND

S9788 is a triazineaminopiperidine derivative capable of reversing multidrug resistance (MDR) in vitro. In preclinical models S9788 was several fold more potent MDR inhibitor than verapamil or cyclosporine. At P-glycoprotein (Pgp) blocking concentrations, S9788 appeared to have only very little toxicity.

PATIENTS AND METHODS

In a two step phase I trial we treated 39 patients with refractory cancer with S9788 and bolus doxorubicin. The steps differed mainly in the S9788 infusion duration; in the first part 23 patients received the MDR-reversing drug S9788 over 30 minutes, in the second step of the study 16 patients were administered S9788 over 150 minutes. The doses of S9788 were escalated in cohorts of three patients up to a dose level (DL) of 96 mg/m2 on the 30 minutes infusion, and to 144 mg/m2 on the 150 minutes infusion. The pharmacokinetics of S9788 were determined.

RESULTS

With the 30-minute infusion schedule symptomatic cardiac arrhythmia were found to be dose limiting. In all patients at the highest DL transient cardiac repolarization prolongation with a long QT-interval on ECG was demonstrated. With the 150-minute administration schedule, S9788 could be escalated up to 144 mg/m2 without subjective toxicity. However, transient QT prolongation was present in all patients. A third degree AV-block and a QT increase of about 40% occurred at the highest DL. Asymptomatic torsade de pointe (DL 96 mg/m2) was demonstrated on Holter recording in one patient. Theses repolarization disturbances with QT increase were considered dose limiting toxicity and the trial was closed. No arrhythmia related death was noted. Pharmacokinetics were similar with both infusion schedules with a mean alpha half life of 11.3 and 13.2 minutes, for the 30-minute and 150-minute infusion, and a terminal half life of 13.5 and 15 hours, respectively. QTc prolongation duration appeared to be dose-dependent.

CONCLUSIONS

With the tested infusion schedules, cardiac toxicity, in particular AV-blocks and QT prolongation, leading to ventricular arrhythmia and torsade de pointe, are the dose limiting toxicities of S9788. Our experience together with the observation of asymptomatic torsade de pointe in two other phase 1 trials of S9788 infused over six hours precluded the further clinical development of S9788.

Serum sex hormones are altered in patients with chronic temporal lobe epilepsy receiving anticonvulsant medication

PURPOSE

To evaluate the changes in serum sex hormones of gonadal or adrenal origin, the gonadotropic hormones, and sex hormone-binding globulin (SHBG) in men and women with chronic temporal lobe epilepsy (TLE), who are undergoing monotherapy with carbamazepine or receiving carbamazepine in combination with other anticonvulsant drugs.

METHODS

Gonadal hormones (estradiol, testosterone, free testosterone, and inhibin B), adrenal hormones [cortisol, dehydroepiandrosterone sulfate (DHEAS), androstenedione, and 17alpha-hydroxyprogesterone], and gonadotropic hormones (luteinizing hormone [LH] and follicle-stimulating hormone [FSH]) were measured in 22 women and 26 men with TLE. The study also measured prolactin; human growth hormone and its major mediator, insulin-like growth factor-I; thyroid hormones (free thyroxine and free triiodothyronine); thyroid-stimulating hormone (TSH); and SHBG. The results were compared with those obtained from 60 healthy women and 106 healthy men.

RESULTS

In the female patients, TSH, DHEAS, follicular-phase LH, and luteal-phase estradiol were significantly lower than in the control groups, with prolactin and SHBG significantly higher. In the male patients, DHEAS, 17alpha-hydroxyprogesterone, free testosterone, inhibin B, and the testosterone/LH ratio were significantly lower than in the control group, with LH, FSH, and SHBG significantly higher. Increased FSH in 31% of the men indicates an impairment of spermatogenesis; lowered inhibin B in 12% indicates an impaired Sertoli's cell function; and the decreased testosterone/LH ratio in 50% indicates an impaired Leydig's cell function.

CONCLUSIONS

The case patients had endocrine disorders, mainly concerning the gonadotropic and gonadal functions in both sexes; the adrenal function, with lowered DHEAS levels in both sexes; and lowered 17alpha-hydroxyprogesterone levels in the men. SHBG levels were increased in patients taking anticonvulsant medications.

Pharmacokinetics of temozolomide in association with fotemustine in malignant melanoma and malignant glioma patients: comparison of oral, intravenous, and hepatic intra-arterial administration

PURPOSE

Depletion of the DNA repair enzyme O6-alkylguanine-DNA alkyltransferase (AT) has been shown to increase tumor sensitivity to chloroethylnitrosoureas. Temozolomide (TMZ), an analogue of dacarbazine, can deplete AT, suggesting that it may be used to sensitize tumors to chloroethylnitrosoureas. However, the influence of nitrosoureas on the pharmacokinetics of TMZ is unknown, and a pilot study was performed to assess the pharmacokinetics of TMZ given via, various routes to 29 patients (27 malignant melanomas, 2 gliomas) with or without sequential administration of i.v. fotemustine.

METHODS

On day 1, TMZ was given intravenously (i.v.), orally (p.o.), or by intra-hepatic arterial infusion (h.i.a.) at four ascending dose levels (150 to 350 mg/m2 per day). On day 2 the same dose of TMZ was given by the same route (or by another route in six patients for determination of its bioavailability), followed 4 h later by fotemustine infusion at 100 mg/m2. Plasma and urinary levels of TMZ were determined on days 1 and 2 by high-performance liquid chromatography after solid-phase extraction.

RESULTS

The pharmacokinetics of i.v. TMZ appeared linear, with the area under the curve (AUC) increasing in proportion to the dose expressed in milligrams per square meter (r = 0.86 and 0.91 for days 1 and 2, respectively). The clearance after i.v. administration was 220 +/- 48 and 241 +/- 39 ml/min on days 1 and 2, respectively. The apparent clearance after p.o. and h.i.a. administration was 290 +/- 86 and 344 +/- 77 ml/min, respectively. The volume of distribution of TMZ after i.v., p.o., and h.i.a. administration was 0.4, 0.6, and 0.6 l/kg on day 1 and 0.5, 0.5, and 0.6 l/kg on day 2, respectively. The absolute bioavailability of TMZ was 0.96 +/- 0.1, regardless of the sequence of the i.v.-p.o. or p.o.-i.v. administration, confirming that TMZ is not subject to a marked first-pass effect. A comparison of TMZ pharmacokinetics after i.v. and h.i.a. treatment at the same infusion rate revealed little evidence of hepatic extraction of TMZ. However, the systemic exposure to TMZ (AUC) appeared to decrease at a lower infusion rate. TMZ excreted unchanged in the urine accounted for 5.9 +/- 3.4% of the dose, with low within-patient and high interpatient variability. TMZ crosses the blood-brain barrier and the concentration detected in CSF amounted to 9%, 28%, and 29% of the corresponding plasma levels (three patients). The equilibrium between plasma and ascitic fluid was reached after 2 h (assessed in one patient).

CONCLUSION

The sequential administration of fotemustine at 4 h after TMZ treatment had no clinically relevant influence on the pharmacokinetics of TMZ. The potential clinical effect of TMZ given by h.i.a. or by locoregional administration has yet to be established, as has the impact of the infusion duration on patients' tolerance and response rate.

New antiepileptic drugs in epileptology

New antiepileptic drugs have been developed and released for the treatment of chronic focal and secondarily generalized epileptic seizures. The anticonvulsant efficacy of these drugs (vigabatrin, lamotrigine, gabapentin, felbamate, tiagabine, topiramate and oxcarbazepine) does not seem to be superior to that of traditional anticonvulsants. The main advantage of these newly developed drugs is a different spectrum of possible adverse events (i.e. these drugs usually do not induce sedation). Moreover, interactions with traditional anticonvulsants are less common, therefore, comedication with these drugs shows an improved tolerability. The availability of new antiepileptic drugs enables us to establish an individually tailored anticonvulsant strategy for each patient.

IS1245 restriction fragment length polymorphism typing of Mycobacterium avium isolates: proposal for standardization

Mycobacterium avium has become a major human pathogen, primarily due to the emergence of the AIDS epidemic. Restriction fragment length polymorphism (RFLP) typing, using insertion sequence IS1245 as a probe, provides a powerful tool in the molecular epidemiology of M. avium-related infections and will facilitate well-founded studies into the sources of M. avium infections in animal and environmental reservoirs. The standardization of this technique allows computerization of IS1245 RFLP patterns for comparison on a local level and the establishment of M. avium DNA fingerprint databases for interlaboratory comparison. Moreover, by combining international DNA typing results of M. avium complex isolates from a broad spectrum of sources, long-lasting questions on the epidemiology of this major agent of mycobacterial infections will be answered.

Superior caval venous syndrome after atrial switch procedure: relief of complete venous obstruction by gradual angioplasty and placement of stents

Superior caval venous syndrome is one of the late problems known to occur after Mustard repair of complete transposition. Reoperation may leave residual stenosis, and carries substantial risk for the patient. It is now feasible to use intravascular stents to overcome systemic venous baffle obstructions, and such an approach is probably more effective. The purpose of our study therefore, was to assess immediate and medium term results of inserting stents subsequent to gradual balloon enlargement of acquired atresia of the intraatrial baffle in patients who had undergone an atrial switch operation. We investigated five patients with complete obstruction of the superior caval venous pathway at perforation of the atretic segment was achieved using a guide wire technique. The procedure was successful in all patients. Gradual angioplasty was performed and intravascular stents were implanted. The pressure in the superior caval vein dropped to normal values, symptoms improved, and the patency of the newly created venoatrial communication was proven at mid-term follow-up. Thus critical obstructions at the superior caval venous pathway after the Mustard procedure can be reopened by interventional catheterization. Implantation of balloon-expandable intravascular stents is safe and effective in the acute relief of the obstructions, but careful long-term follow-up is mandatory.

[Comparison of adjuvant chemotherapy in breast carcinoma with a combination of cyclophosphamide, methotrexate, 5-fluorouracil (CMF) and AC (doxorubicin, cyclophosphamide). Initial results of a national cooperative study]

The aim of this multicentric, prospective randomized trial is to evaluate and to compare, effects and toxicities of two chemotherapeutic combinations (AC and CMF) in adjuvant treatment of breast cancer. Both combinations were given in equitoxic doses and number of cycles was only four. There are 106 women treated for breast cancer T1c-3a, N0-1, M0 in the study. After surgery the patients were randomized, 54 for AC combination and 52 for CMF. We evaluate toxicity of this treatment in all patients in the study. Hematological and nonhematological side effects were comparable in both groups except alopecia (in the group AC was 100%). The study is not finished yet. Preliminary analysis does not show any difference between these two groups.

Proteins of newly isolated mutants and the amino-terminal proline are essential for ubiquitin-proteasome-catalyzed catabolite degradation of fructose-1,6-bisphosphatase of Saccharomyces cerevisiae

Addition of glucose to cells of the yeast Saccharomyces cerevisiae growing on a non-fermentable carbon source leads to selective and rapid degradation of fructose-1,6-bisphosphatase. This so called catabolite inactivation of the enzyme is brought about by the ubiquitin-proteasome system. To identify additional components of the catabolite inactivation machinery, we isolated three mutant strains, gid1, gid2, and gid3, defective in glucose-induced degradation of fructose-1,6-bisphospha-tase. All mutant strains show in addition a defect in catabolite inactivation of three other gluconeogenic enzymes: cytosolic malate dehydrogenase, isocitrate lyase, and phosphoenolpyruvate carboxykinase. These findings indicate a common mechanism for the inactivation of all four enzymes. The mutants were also impaired in degradation of short-lived N-end rule substrates, which are degraded via the ubiquitin-proteasome system. Site-directed mutagenesis of the amino-terminal proline residue yielded fructose-1,6-bisphosphatase forms that were no longer degraded via the ubiquitin-proteasome pathway. All amino termini other than proline made fructose-1,6-bisphosphatase inaccessible to degradation. However, the exchange of the amino-terminal proline had no effect on the phosphorylation of the mutated enzyme. Our findings suggest an essential function of the amino-terminal proline residue for the degradation process of fructose-1,6-bisphosphatase. Phosphorylation of the enzyme was not necessary for degradation to occur.

Structure-activity relationship of synthetic phosphoinositolglycans mimicking metabolic insulin action

Phosphoinositolglycan (PIG) molecules have been implicated to stimulate glucose and lipid metabolism in insulin-sensitive cells and tissues in vitro and in vivo. The structural requirements for this partial insulin-mimetic activity remained unclear so far. For establishment of a first structure-activity relationship, a number of PIG compounds were synthesized consisting of the complete or shortened/mutated glycan moiety derived from the structure of the glycosylphosphatidylinositol (GPI) anchor of the GPI-anchored protein, Gce1p, from yeast. The PIG compounds were divided into four classes according to their insulin-mimetic activity in vitro with the typical representatives: compound 41, HO-SO2-O-6Manalpha1(Manalpha1-2)-2Manalpha1 (6-HSO3)- -6Manalpha1-4GluNb eta1-6(D)inositol-1,2-(cyclic)-phosphate; compound 37, HO-PO(H)O-6Manalpha1(Manalpha1-2)-2Manalpha1-6Manal pha1-4GluNbeta1-6( D)inositol-1,2-(cyclic)-phosphate; compound 7, HO-PO(H)O-6Manalpha1-4GluN(1-6(L)inositol-1,2-(cyclic)-ph osp hate; and compound 1, HO-PO(H)O-6Manalpha1-4GluN(1-6(L)inositol. Compounds 41 and 37 stimulated lipogenesis up to 90% (at 20 microM) of the maximal insulin response but with differing concentrations required for 50% activation (EC50 values 2.5 +/- 0.9 vs 4.9 +/- 1.7 microM) as well as glycogen synthase (4.7 +/- 1 vs 9.5 +/- 1.5 microM) and glycerol-3-phosphate acyltransferase (3.5 +/- 0.8 vs 8.0 +/- 1.1 microM). Compound 7 was clearly less potent (20% of the maximal insulin response at 100 microM), whereas compound 1 was almost inactive. This relative ranking in the insulin-mimetic potency between members of the PIG classes (e.g., 41 > 37 >> 7 > 1) was also observed for the (i) activation of glucose transport and glucose transporter isoform 4 translocation in isolated normal and insulin-resistant adipocytes, (ii) inhibition of lipolysis in adipocytes, (iii) stimulation of glucose transport and glycogen synthesis in isolated normal and insulin-resistant diaphragms, and (iv) induction of tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) in diaphragms. The complete glycan core structure (Man3-GluN) of typical GPI anchors including a mannose side chain and the inositolphosphate moiety was required for maximal insulin-mimetic activity of the PIG compounds with some variations possible with respect to the type of residues coupled to the terminal mannose/inositol as well as the type of linkages involved. These data argue for the potency and specificity of the interaction of PIG molecules with putative signaling component(s) (presumably at the level of the IRS proteins) in adipose and muscle cells which finally lead to insulin-mimetic metabolic activity even in insulin-resistant states.

Early-onset Alzheimer's disease due to mutations of the presenilin-1 gene on chromosome 14: a 7-year follow-up of a patient with a mutation at codon 139

Mutations in the presenilin-1 gene (PS-1 gene) on chromosome 14 have recently been identified as a cause of familial early-onset Alzheimer's disease (EOAD). To our knowledge, only two German EOAD patients with mutations in the PS-1 gene have been identified thus far. Herein we report the case of a German EOAD patient with a family history of dementia and a missense mutation at codon 139 (M139V) of the PS-1 gene. The patient came to our clinic for the first time when he was 44 years old. During the following 7 years, his Mini-Mental State Examination (MMSE) score dropped from 24 to 0. Myocloni were an early neurological symptom that was already present during the first consultation. We could demonstrate that myoclonic activity was of cortical origin using a back-averaging method. Magnetic resonance imaging (MRI) revealed only slight changes in the early stage of the disease. Follow-up MRI studies showed progression of bitemporal ventricular enlargement and progressive frontal and temporal cortical atrophy. Although the majority of EOAD patients belong to the sporadic (non-genetic) type of AD, early-onset dementia, early myocloni and a familial history of AD should direct attention to the possibility of a genetic form of AD.

Oligodendrocyte apoptosis and primary demyelination induced by local TNF/p55TNF receptor signaling in the central nervous system of transgenic mice: models for multiple sclerosis with primary oligodendrogliopathy

The scientific dogma that multiple sclerosis (MS) is a disease caused by a single pathogenic mechanism has been challenged recently by the heterogeneity observed in MS lesions and the realization that not all patterns of demyelination can be modeled by autoimmune-triggered mechanisms. To evaluate the contribution of local tumor necrosis factor (TNF) ligand/receptor signaling pathways to MS immunopathogenesis we have analyzed disease pathology in central nervous system-expressing TNF transgenic mice, with or without p55 or p75TNF receptors, using combined in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling and cell identification techniques. We demonstrate that local production of TNF by central nervous system glia potently and selectively induces oligodendrocyte apoptosis and myelin vacuolation in the context of an intact blood-brain barrier and absence of immune cell infiltration into the central nervous system parenchyma. Interestingly, primary demyelination then develops in a classical manner in the presence of large numbers of recruited phagocytic macrophages, possibly the result of concomitant pro-inflammatory effects of TNF in the central nervous system, and lesions progress into acute or chronic MS-type plaques with axonal damage, focal blood-brain barrier disruption, and considerable oligodendrocyte loss. Both the cytotoxic and inflammatory effects of TNF were abrogated in mice genetically deficient for the p55TNF receptor demonstrating a dominant role for p55TNF receptor-signaling pathways in TNF-mediated pathology. These results demonstrate that aberrant local TNF/p55TNF receptor signaling in the central nervous system can have a potentially major role in the aetiopathogenesis of MS demyelination, particularly in MS subtypes in which oligodendrocyte death is a primary pathological feature, and provide new models for studying the basic mechanisms underlying oligodendrocyte and myelin loss.

[Anticonvulsant combination therapy: rational concepts versus real effectiveness]

Primary drug treatment of epilepsies is usually a monotherapy with an antiepileptic drug. This procedure causes less side effects as polytherapy and probably shows the same efficacy. Two third of patients with focal epilepsies are sufficiently treated with a single antiepileptic drug: 60% of patients with Grand mal and 22-30% of patients with complex focal seizures remain seizures free. An alternative monotherapy will suppress seizures in another 30% of patients. With polytherapy this is achieved in only 12% of the remaining patients, furthermore, side effects increase in polytherapy. Generalized epilepsies are usually treated with valproate monotherapy. Patients remain seizure free from absence in 60-90%, from myoclonic-impulsive seizures in 75-97% and from Grand mal in about 85%. Alternative monotherapy is less common because of the limited efficacy and possible side effects of drugs: ethosuximide does not control Grand mal and phenobarbitone may cause sedation. Thus, polytherapy is commonly initiated when monotherapy fails to control seizures (lamotrigine is often chosen as comedication). Rational polypharmacy is a term suggesting rational concepts in planning antiepileptic polytherapy leading to a superior anticonvulsant effect. However, this consideration is not based on or supported by clinical data. Yet, a combination of drugs which have no or little pharmacokinetic interactions seems to be a clinically relevant recommendation. Thus, newly developed drugs such as vigabatrin, lamotrigine or gabapentin are more frequently used as comedication with standard antiepileptic drugs.

T-cell apoptosis in inflammatory brain lesions: destruction of T cells does not depend on antigen recognition

Elimination of inflammatory T cells by apoptosis appears to play an important role in the down-regulation of inflammation in the central nervous system. Here we report that apoptosis of T lymphocytes occurs to a similar extent in different models of autoimmune encephalomyelitis. Apoptosis is restricted to cells located in the neuroectodermal parenchyma, thereby leaving T cells present in the brain's connective tissue compartments unharmed. Death of T cells in the parenchyma does not depend on antigen presentation by resident microglial cells or astrocytes. Adoptive transfer experiments with T lymphocytes carrying a specific genetic marker revealed that in the central nervous system these cells are destroyed regardless of their antigen specificity or state of activation. Although many of both antigen-dependent and -independent mechanisms in the induction of T-cell apoptosis may act simultaneously, our results suggest that the nervous system harbors a specific, currently undefined, mechanism that effectively eliminates infiltrating T lymphocytes.

Cardiorespiratory stability of premature boys and girls during kangaroo care

The objective of the investigation was to study the stability of the cardiorespiratory system of 20 premature boys and girls during maternal kangaroo care (KC) and in the incubator. Stability of heart rate, respiration and oxygen saturation was compared in a pretest-test-posttest design by means of a stability score. The three stability items and the total stability did not change significantly during the three conditions. In some individuals the stability either increased or decreased markedly during Kangaroo Care. The boys showed significantly less cardiorespiratory stability both during kangaroo care and in the incubator compared to the girls.

Coarctation of the thoraco-abdominal aorta: operative treatment with a cryopreserved arterial homograft in a seven-year-old boy

Compared to coarctation in the proximal descending aorta near the insertion of the ligamentum arteriosum, coarctation in the aortic arch, the lower descending or the abdominal aorta is a relatively rare disease. Operative treatment of abdominal coarctation is more complicated if there are concomitant stenoses of visceral or renal arteries. In young patients, surgical procedure and outcome is additionally determined by caliber and compliance mismatch between still growing native vessels and arterial substitute. Our report deals with a seven-year-old male patient, who was first diagnosed as having coarctation of the aorta at five years of age due to distinct bilateral brachial hypertension. The angiogram revealed a narrowing of the aorta, approximately ten centimeters in length, from the lower descending segment down to the proximal abdominal part of the aorta. The origin of the superior mesenteric artery and both renal arteries were not involved in the pathological process. Arterial reconstruction was carried out by anastomosis of cryopreserved arterial homograft with the thoracic aorta and with the abdominal aorta distal to the origin of the renal arteries. The postoperative course was uneventful, duplex sonography revealed no pressure gradient between the thoracic and abdominal aorta and brachial blood pressure was within normal ranges.