The efficacy of lamotrigine in children and adolescents with refractory generalized epilepsy: a randomized, double-blind, crossover study

In the 9L rat brain tumour model the damage to tumour and normal brain by photodynamic therapy after intratumoural photosensitizer administration (intratumoural PDT) was studied. Twenty four rats received an intratumoural injection of 4 or 40 mm3 haematoporphyrin derivative (HpD, 5 mg ml-1), followed by interstitial irradiation with 20 Joule (J) (630 nm) 5 h later. For comparison, seven rats were treated with 20 Joule 24 h after an intravenous injection of 10 mg kg-1 HpD (intravenous PDT). With the chosen PDT parameters there was no important difference between the damaged areas produced by intratumoural PDT or intravenous PDT. No selective tumour kill was observed. Even though normal brain tissue was heavily damaged, vital tumour parts were still present. Intravenous PDT caused extensive diffuse damage to small blood vessels in tumour and surrounding normal brain. Intratumoural PDT was characterised by an infiltration of polymorphonuclear cells into damaged tissue, dilatation of larger blood vessels and gross haemorrhage. These results suggest an immediate vascular shutdown in the intravenous approach, while in the intratumoural approach the vasculature remained patent initially. Because of the severe side effects observed, the use of HpD seems not advisable for intratumoural PDT of brain tumours.     

A new method for freezing testicular biopsy sperm: three pregnancies with sperm extracted from cryopreserved sections of seminiferous tubule

OBJECTIVE: To determine whether spermatozoa, located in the seminiferous tubules obtained by needle puncture testicular biopsy, could be cryopreserved successfully within the tubules and subsequently be used for in oocyte fertilization via intracytoplasmic sperm injection (ICSI) after the spermatozoa were removed from the thawed tubules. DESIGN: Clinical case series. SETTING: Private IVF unit. PATIENT(S): Six azoospermic patients (four obstructive, two maturation arrest). MAIN OUTCOME MEASURE(S): Survival rate of thawed spermatozoa, fertilization rate of oocytes after ICSI with spermatozoa extracted from thawed tubules and pregnancies. RESULT(S): All six patients had adequate motile spermatozoa extracted from the thawed tubule sections, and all patients achieved fertilization via ICSI with their partner's eggs. The fertilization rate was 46%, compared with 56% obtained in other previous patient cycles using fresh testicular spermatozoa. Three pregnancies resulted from five ETs. CONCLUSION(S): Cryopreservation and subsequent thawing of seminiferous tubules proved to be a simple and successful method for storage of testicular spermatozoa, reducing the need for repetitive testicular biopsies and increasing the likelihood of sperm availability on the day of oocyte retrieval.     

Heterozygosity for a defective gene for CC chemokine receptor 5 is not the sole determinant for the immunologic and virologic phenotype of HIV-infected long-term nonprogressors

HIV-1-infected long-term nonprogressors are a heterogeneous group of individuals with regard to immunologic and virologic markers of HIV-1 disease. CC chemokine receptor 5 (CCR5) has recently been identified as an important coreceptor for HIV-1 entry into CD4+ T cells. A mutant allele of CCR5 confers a high degree of resistance to HIV-1 infection in homozygous individuals and partial protection against HIV disease progression in heterozygotes. The frequency of CCR5 heterozygotes is increased among HIV-1- infected long-term nonprogressors compared with progressors; however, the host defense mechanisms responsible for nonprogression in CCR5 heterozygotes are unknown. We hypothesized that nonprogressors who were heterozygous for the mutant CCR5 gene might define a subgroup of nonprogressors with higher CD4+ T cell counts and lower viral load compared with CCR5 wild-type nonprogressors. However, in a cohort of 33 HIV-1-infected long-term nonprogressors, those who were heterozygous for the mutant CCR5 gene were indistinguishable from CCR5 wild-type nonprogressors with regard to all measured immunologic and virologic parameters. Although epidemiologic data support a role for the mutant CCR5 allele in the determination of the state of long-term nonprogression in some HIV-1- infected individuals, it is not the only determinant. Furthermore, long-term nonprogressors with the wild-type CCR5 genotype are indistinguishable from heterozygotes from an immunologic and virologic standpoint.     

Effects of different protective agents on the phototoxicity of fluoranthene to Daphnia magna

OBJECTIVE: To determine if a risk prediction model for patients with unstable angina would predict resource utilization. METHODS AND RESULTS: Four hundred sixty-five consecutive patients admitted for unstable angina to a tertiary care university-based medical center were prospectively evaluated from June 1, 1992, to June 30, 1995. The proportion of patients receiving coronary angiography, coronary angioplasty, and coronary artery bypass grafting were analyzed according to four risk groups on the basis of a previously published model: Group 1, <2% risk of major complication; Group 2, 2.1% to 5% risk; Group 3, 5.1 % to 15% risk; and Group 4, >15.1 % risk. Hospital length of stay and estimated cost of hospitalization based on DRG and specific payer ratio of cost-to-charge were also compared between groups. Multiple linear regression analysis was used to determine the influence of estimated risk and procedures on hospital costs. The four groups were well matched for gender, hypertension, tobacco history, and previous percutaneous transluminal coronary angioplasty and myocardial infarction. Group 4 had a higher incidence of previous coronary bypass grafting (35% vs 10%, p=0.001) and triple vessel or left main coronary artery disease compared with Group 1 (44% vs 13%, p=0.041). Group 4 patients were more likely to be admitted to the coronary care unit compared with Group 2 or Group 1 patients (80% vs Group 1: 51% [p= 0.001]; and vs Group 2: 53% [p=0.001]), more likely to receive heparin (87% vs 71%, p=0.007), and more likely to receive a beta-blocker or calcium channel blocker (89% vs 74%, p=0.008) than Group 1. Coronary angioplasty rates were similar for all groups, but Group 4 patients were more likely to receive coronary bypass grafting than Group 2 or Group 1 (27% vs Group 2: 12%, p=0.004 and vs Group 1: 8%, p=0.002). Hospital length of stay was highest in Group 4 and lowest for Group 1. Average hospital costs were significantly less in Group 3 than in Group 4, but higher than in Group 1. Multivariate analysis determined a dependency of costs on risk group with Group 2 having costs 31.4% (95% CI=9.8 to 57.2), Group 3 46.7% (24, 3 to 73.1), and Group 4 75% (46.9 to 110.7) higher than Group 1. The use of procedures also significantly increased costs, with PTCA-treated patients having a 44.9% (26.7 to 65.7) increase in costs compared with medically treated patients, and surgically treated patients having a 204.7% increase in costs. CONCLUSION: Resource utilization as assessed by the use of revascularization procedures, length of stay, and hospital costs are influenced by patient acuity estimated from a prediction model on the basis of estimated risk of cardiac complications. The model exerts independent influence on cost even after adjustment for various procedures. The use of revascularization procedures, especially coronary artery surgery, remains a large determinant of hospital cost.     

Anoxia-induced neuronal injury: role of Na+ entry and Na+-dependent transport

An important cause of anoxia-induced nerve injury involves the disruption of the ionic balance that exists across the neuronal membrane. This loss of ionic homeostasis results in an increase in intracellular calcium, sodium, and hydrogen and is correlated with cell injury and death. Using time-lapse confocal microscopy, we have previously reported that nerve cell injury is mediated largely by sodium and that removing extracellular sodium prevents the anoxia-induced morphological changes. In this study, we hypothesized that sodium enters neurons via specific mechanisms and that the pharmacologic blockade of sodium entry would prevent nerve damage. In cultured neocortical neurons we demonstrate that replacing extracellular sodium with NMDG+ prevents anoxia-induced morphological changes. With sodium in the extracellular fluid, various routes of sodium entry were examined, including voltage-sensitive sodium channels, glutamate receptor channels, and sodium-dependent chloride-bicarbonate exchange. Blockade of these routes had no effect. Amiloride, however, prevented the morphological changes induced by anoxia lasting 10, 15, or 20 min. At doses of 10 microM-1 mM, amiloride protected neurons in a dose-dependent fashion. We argue that amiloride acts on a Na+-dependent exchanger (e.g., Na+-Ca2+) and present a model to explain these findings in the context of the neuronal response to anoxia.     

Monocyte activation on titanium-sputtered polystyrene surfaces in vitro: the effect of culture conditions on interleukin-1 release

The release of interleukin-1 alpha (IL-1 alpha) by human peripheral blood monocytes cultured for 24 and 48 h on polystyrene (PS) and titanium-sputtered polystyrene (Ti) was evaluated. Magnetron sputtering of the PS surfaces resulted in a formation of a 50-nm-thick coat, consisting of an outer layer of TiO2. Monocytes released IL-1 alpha without the addition of exogenous stimuli. A doubling of the culture time from 24 to 48 h did not have a major effect on the amount of IL-1 alpha released. The IL-1 alpha levels were increased by addition of lipopolysaccharide (LPS). High concentrations of PS particles (1 and 3 microns diameter) were equally effective stimuli for IL-1 alpha release as LPS. Preadsorption of fibronectin to culture plates augmented LPS-stimulated IL-1 alpha secretion, whereas preadsorbed fibrinogen had an inhibitory effect. Our observation indicate a direct activation of monocytes by PS and Ti, resulting in IL-1 alpha secretion, which is modified by protein adsorption and exogenous stimuli.     

Molecular dynamics simulation of a 13-mer duplex DNA: a PvuII substrate

Parallel version of AMBER 4.1 was ported and optimised on the Indian parallel supercomputer PARAM OpenFrame built around Sun Ultra Sparc processors. This version of AMBER program was then used to carry out molecular dynamics (MD) simulations on 5'-TGACCAGCTGGTC-3', a substrate for PvuII enzyme. MD simulations in water are carried out under following conditions: (i) unconstrained at 300 K (230 ps); (ii) unconstrained at 283 K (500 ps); (iii) Watson-Crick basepair constrained at 283 K (1 ns); and (iv) Watson-Crick basepair constrained with ions at 283 K (1.2 ns). In all these simulation studies, the molecule was observed to be bending and maximum distortions in the double helix around was seen around the G7:C7' basepair, which is the phosphodiester bond that is cleaved by PvuII. Analysis of MD simulation with ions carried out for 1.2 ns also pointed out that the conformation of double helix alternates between a conformation close to B-form and close to A-form. It is argued that a bent non-standard conformation is recognised by the PvuII enzyme. The maximum bend occurs at the G7:C7' region, weakening the phosphodiester bond and allows His48 to get placed in such a fashion to permit the scission through a general base mechanism. The bending and distortion observed is a property of the sequence which acts as a substrate for PvuII enzyme. This is confirmed by carrying out MD studies on the Dickerson's sequence d(CGCGAATTCGCG)2 as a reference molecule, which practically does not bend or get deformed.