Passage of irinotecan and its active metabolite, SN-38, into human milk.

WHAT IS KNOWN AND OBJECTIVE: We measured the levels of irinotecan and its active metabolite, SN-38, in human milk after the administration of irinotecan to assess the potential risks when women treated with irinotecan nurse their infants. CASE SUMMARY: Human milk was collected for 6 days starting on the day after irinotecan was administered. The levels of irinotecan and SN-38 in human milk were measured using liquid chromatography-mass spectrometry. Irinotecan was detected on Days 2 and 3 but not after Day 4. A strong signal indicating the presence of SN-38 was detected on Day 2 and the signal was readily detected until Day 7, indicating that SN-38 remained in human milk. WHAT IS NEW AND CONCLUSION: Intravenously administered CPT-11 continues to pass into human milk over a prolonged period in the form of its active metabolite, SN-38. The relationship between administration of CPT-11 and SN-38 exposure and toxicity is still not well defined, so patients should avoid nursing their infants while they are being treated with CPT-11.

Gestational immune activation and Tsc2 haploinsufficiency cooperate to disrupt fetal survival and may perturb social behavior in adult mice.

Approximately 40-50% of individuals affected by tuberous sclerosis (TSC) develop autism spectrum disorders (ASDs). One possible explanation for this partial penetrance is an interaction between TSC gene mutations and other risk factors such as gestational immune activation. In this study, we report the interactive effects of these two ASD risk factors in a mouse model of TSC. Combined, but not single, exposure had adverse effects on intrauterine survival. Additionally, provisional results suggest that these factors synergize to disrupt social approach behavior in adult mice. Moreover, studies in human populations are consistent with an interaction between high seasonal flu activity in late gestation and TSC mutations in ASD. Taken together, our studies raise the possibility of a gene × environment interaction between heterozygous TSC gene mutations and gestational immune activation in the pathogenesis of TSC-related ASD.

Unilateral cortical activity in newborn humans: an early index of cerebral dominance?

Spectral analyses show unilateral photic driving in newborn human infants to bilateral repetitive visual stimulation. Results are interpreted as evidence of dominance in the right hemisphere for rhythmic visual stimuli and lack of interhemispheric integration.

Bilateral cingulum fiber reductions in temporal lobe epilepsy with unilateral hippocampal sclerosis.

PURPOSE: To evaluate whether white matter tracts within the Papez circuit are altered in patients with unilateral hippocampal sclerosis (HS). METHODS: Twenty patients with histologically proven unilateral HS and 20 age-matched controls were studied with a 3T Epilepsy-dedicated MRI protocol including a MPRAGE sequence for hippocampus volumetry and a diffusion tensor imaging (DTI) sequence (61 diffusion-encoding directions, 2×2×2mm3 voxels) for diffusion tensor tractography (DTT). An energy-based global tracking algorithm was used to calculate streamline counts (SC) and fractional anisotropy (FA) of cingulate, fornix, and mammillo-thalamic tracts, respectively. RESULTS: Sclerotic hippocampi were significantly smaller compared to the contralateral side and to age-matched controls. Cingulum SC but not FA were reduced on the hippocampal sclerosis (258+81.0) and contralateral side (271+85.6) compared to age-matched controls (447+138). CONCLUSION: Focusing on white matter tracts of the Papez circuit we showed that in patients with intractable temporal lobe epilepsy unilateral hippocampal sclerosis is associated with a bilateral reduction of cingulum association fibers projecting from the cingulate gyrus to the parahippocampal gyrus.

Characterisation and mitochondrial localisation of AUH, an AU-specific RNA-binding enoyl-CoA hydratase.

AU-rich elements function as instability elements which direct rapid mRNA degradation. AUH protein exhibits an AU-specific RNA-binding property and an intrinsic enoyl-CoA hydratase activity and may therefore function to link mRNA decay to metabolic processes (. Proc. Natl. Acad. Sci. USA 92, 2051-2055). The sequence encoding the murine protein, muAUH, was established by cloning, and the corresponding polypeptide predicted to have a molecular mass of 37kDa. As shown for the human protein, muAUH is expressed in a 32kDa form and there is 94% homology between the two species. Recombinant muAUH was shown to be an RNA-binding enoyl-CoA hydratase. All murine cells studied contained a single AUH transcript of approx. 1.7kb and an investigation of tissue-specific expression revealed highest levels in kidney, skeletal muscle, heart, liver and spleen. It was further determined, using immunoelectron microscopy, that AUH is located in the mitochondria of mouse cells.

Randomized trial of vigabatrin in patients with infantile spasms.

BACKGROUND: Infantile spasms are a rare but devastating pediatric epilepsy that, outside the United States, is often treated with vigabatrin. The authors evaluated the efficacy and safety of vigabatrin in children with recent-onset infantile spasms. METHODS: This 2-week, randomized, single-masked, multicenter study with a 3- year, open-label, dose-ranging follow-up study included patients who were younger than 2 years of age, had a diagnosed duration of infantile spasms of no more than 3 months, and had not previously been treated with adrenocorticotropic hormone, prednisone, or valproic acid. Patients were randomly assigned to receive low-dose (18-36 mg/kg/day) or high-dose (100-148 mg/kg/day) vigabatrin. Treatment responders were those who were free of infantile spasm for 7 consecutive days beginning within the first 14 days of vigabatrin therapy. Time to response to therapy was evaluated during the first 3 months, and safety was evaluated for the entire study period. RESULTS: Overall, 32 of 142 patients who were able to be evaluated for efficacy were treatment responders (8/75 receiving low-dose vigabatrin vs 24/67 receiving high doses, p < 0.001). Response increased dramatically after approximately 2 weeks of vigabatrin therapy and continued to increase over the 3-month follow-up period. Time to response was shorter in those receiving high-dose versus low-dose vigabatrin (p = 0.04) and in those with tuberous sclerosis versus other etiologies (p < 0.001). Vigabatrin was well tolerated and safe; only nine patients discontinued therapy because of adverse events. CONCLUSIONS: These results confirm previous reports of the efficacy and safety of vigabatrin in patients with infantile spasms, particularly among those with spasms secondary to tuberous sclerosis.

Application of an air-filled tube for measuring intraesophageal pressure.

We devised a new method for measuring esophageal pressure (Pes) with use of a flexible tube without a balloon at a constant rate of airflow through the tube into the esophagus (balloonless method). A study with 133Xe showed that the air that accumulated in the esophagus did not interfere with the measurement of Pes. We measured dynamic compliance (Cdyn) and pulmonary resistance (RL) with the balloonless method in 19 subjects and obtained a static deflation pressure-volume curve (P-V curve) in 10 other subjects. Cdyn was 0.243 +/- 0.099 l/cmH2O and RL was 1.52 +/- 0.42 cmH2O.l-1.s. In 6 of the 10 subjects, a P-V curve was also obtained with the balloon tube (balloon method). K, the index of compliance in the exponential function V = V0(1-e-KP) where V0 is volume at infinite pressure, was 0.136 +/- 0.040 cmH2O-1 with the balloonless method and 0.153 +/- 0.023 cmH2O-1 with the balloon method. No statistically significant difference was found between these two values. In conclusion, Cdyn, RL, and the P-V curve can be obtained precisely with the balloonless method.

Different effects of isoproterenol and dihydroouabain on cardiac Ca2+ transients.

Cytosolic fura-2 Ca2+ transient signals (TCa) and the left ventricular pressure or contraction of myocardium under the positive inotropic effects of the beta-adrenoceptor agonist, isoproterenol, and the cardiac glycoside, dihydroouabain, were measured simultaneously and the results were compared. TCa was observed preceding the onset of force development and showed a steeper rise and slower decay than did the contraction curve of papillary muscle. Isoproterenol increased the steepness and the amplitude of TCa, reflecting the speed and peak force of contraction, and clearly biphasic TCa were observed with biphasic contractions developed at low frequency. Ryanodine reduced not only the early component of the contraction but also TCa, without affecting the diastolic Ca2+ level. These effects of isoproterenol were attributed to the enhanced uptake of Ca2+ by the sarcoplasmic reticulum. In contrast, dihydroouabain elevated the Ca2+ level at diastole without any change in the amplitude of TCa, suggesting that dihydroouabain inhibits the membrane Na pump thereby increasing the intracellular Ca2+ via Na(+)-Ca2+ exchange. Furthermore, a comparison of the time course of the isometric twitch curve with that of TCa in rested state contraction indicated that there are distinct differences between the mechanisms of the positive inotropic effects of isoproterenol and of dihydroouabain.

Protective role of nitric oxide synthase against ischemia-reperfusion injury in guinea pig myocardial mitochondria.

In guinea-pig myocardial mitochondria preparation, lowering the Ca2+ concentration or pH level in the perfusate rapidly elevated the fura-2 Ca2+ signal ([Ca2+]m). Pretreatment with 10(-4) M L-Arg inhibited the rapid [Ca2+]m influx, whereas administration of 10(-4) M L-NAME did not, suggesting some association between nitric oxide (NO*) synthase (NOS) activation and Ca2+ kinetics in mitochondria. Immunoblotting analysis showed that endothelial (e)-NOS was present in mitochondria, but not inducible (i)-NOS or brain (b)-NOS. Electron microscopy observations revealed that the e-NOS antibody-reactive site in the mitochondria was the inner cristae. The production of reactive oxygen species and NO* in isolated mitochondria was detected by the spin trapping technique with electron paramagnetic resonance (EPR) spectrometry. Pretreatment with 10(-5) M S-nitroso-N-acetyl-DL-penicillamine (SNAP) and 10(-5) M 3-[2-Hydroxy-1-(1-methylethyl)-2-nitrosohydrazino]-1-propananin e (NOC 5), which spontaneously generate NO*, completely inhibited the [Ca2+]m uptake. In addition, N-morpholino sydnonimine hydrochloride (SIN-1) (10(-5) M), which simultaneously generates NO* as well as *O2- and peroxynitrite anion (ONOO-), inhibited the increase in [Ca2+]m. ONOO- (3 x 10(-4) M) itself also inhibited this increase. Pretreatment with the *O2(-)-scavenger manganese superoxide dismutase or catalase (200 units/ml) completely inhibited the increase in [Ca2+]m caused by lowering of either the Ca2+ concentration or the pH in the perfusate. These results suggested that the formation of reactive oxygen species promoted the [Ca2+]m influx. The agents that inhibited the [Ca2+]m influx improved contractility even in Langendorff preparations after ischemia. Based on these findings, we concluded that e-NOS exists in mitochondria and that NO* may play an important protective role in reperfusion cardiac injury after ischemia, by inhibiting the Ca2+ influx into mitochondria which are otherwise damaged by *O2-.

Intrahepatic migration of a peritoneal shunt catheter: case report.

The intrahepatic migration of a peritoneal shunt tube of a ventriculoperitoneal shunt system (low pressure Pudenz valve and low pressure Pudenz peritoneal catheter) is reported. This is a rare complication of ventriculoperitoneal shunting and was diagnosed by metrizamide shuntography and abdominal computed tomography. To our knowledge, this is the second case complicated with migration of a peritoneal shunt tube into the liver.

Survival following alpha particle pituitary irradiation for diabetic retinopathy.

The purpose of this study was to evaluate the mortality experience of persons with longstanding diabetes who had received pituitary irradiation for diabetic retinopathy compared to a matched group of persons with diabetes who had not had pituitary ablation. The irradiated cohort consisted of 167 patients treated at the Donner Pavilion (Lawrence Berkeley Laboratory, University of California, Berkeley), and the comparison cohort was the population evaluated in the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR). Survival analyses were performed comparing the two cohorts using three different sets of matching criteria, each more restrictive than the previous analyses. The three different strategies were (1) matched only on severity of diabetic retinopathy; (2) matched on severity of retinopathy and age; and (3) matched on severity of retinopathy, age, gender, and hypertension status. Tests of comparison were the log-rank test, the Wilcoxon test, and the likelihood ratio test. For the model matching only on severity of retinopathy, mean survival was 8.3 years for the WESDR group and 9.4 years for the ablated group (p > 0.05 for all three statistical tests). For the model matched on retinopathy and age, mean survival was 8.9 years for the WESDR group and 9.2 years for the ablated group (p=0.05 log-rank test, 0.32 Wilcoxon test, and 0.06 likelihood ratio test). For the model matching on retinopathy, age, gender, and hypertension status, mean survival was 8.9 years for the WESDR group and 11.6 years for the ablated group (p=0.72 log-rank test, 0.08 Wilcoxon test, and 0.82 likelihood ratio test). These data are compatible with the notion that pituitary ablation, and therefore induced pituitary growth hormone deficiency, may not decrease survival in those with severe diabetic retinopathy.

Molecular cloning, expression and tissue distribution of hamster diacetyl reductase. Identity with L-xylulose reductase.

Using rapid amplification of cDNA ends PCR, a cDNA species for diacetyl reductase (EC 1.1.1.5) was isolated from hamster liver. The encoded protein consisted of 244 amino acids, and showed high sequence identity to mouse lung carbonyl reductase and hamster sperm P26h protein, which belong to the short-chain dehydrogenase/reductase family. The enzyme efficiently reduced L-xylulose as well as diacetyl, and slowly oxidized xylitol. The K(m) values for L-xylulose and xylitol were similar to those reported for L-xylulose reductase (EC 1.1.1.10) of guinea pig liver. The identity of diacetyl reductase with L-xylulose reductase was demonstrated by co-purification of the two enzyme activities from hamster liver and their proportional distribution in other tissues.

Studies on the mechanism of action of imipenem (N-formimidoylthienamycin) in vitro: binding to the penicillin-binding proteins (PBPs) in Escherichia coli and Pseudomonas aeruginosa, and inhibition of enzyme activities due to the PBPs in E. coli.

The binding affinities of imipenem (N- formimidoylthienamycin ) to penicillin-binding proteins ( PBSs ) of Escherichia coli and Pseudomonas aeruginosa were determined by two different methods in which competition with [14C]benzylpenicillin for the binding sites was measured. By both methods imipenem was shown to have very high binding affinities to PBPs-2 and -4 in E. coli and P. aeruginosa, and appreciable affinities to most of their other major PBPs. But higher concentrations of imipenem were required for binding to the PBPs-3 in these bacteria. More direct information about the antibacterial activity of imipenem was obtained by measuring its inhibition of the peptidoglycan-synthetic enzyme activities of E. coli PBPs. The results of enzyme inhibitions were compatible with those obtained in binding experiments. The antibiotic inhibited the transpeptidase activities of PBPs-1A, -1B and -2, and the D-alanine carboxypeptidase activities of PBPs-4 and -5. The antibiotic also seemed to cause strong inhibition of the transglycosylase activity of PBP-1A by some unknown mechanism. It inhibited the transpeptidase activity of PBP-3 only weakly, which is consistent with the findings that it had low binding affinity to PBP-3 and did not inhibit septum formation by the cells.

Intra-operative detection of lymph node involvement in carcinoma of the colon.

BACKGROUND/AIMS: We studied the accuracy rate of intra-operative lymph node assessment compared with pathological examination to determine whether surgeons could modify the extent of lymphadenectomy during the operation. METHODOLOGY: Intra-operative and pathological lymph node assessments were compared in 360 patients with carcinoma of the colon. RESULTS: A total of 6,431 lymph nodes were examined, mean number per patient was 17.9. The overall accuracy rate of intra-operative diagnosis was 56.1%, sensitivity was 93.2%, and specificity was 41.7%. The accuracy rate of the diagnosis of N1 and N2 was 43.7% and that of N3 and N4 was 78.3% (p=0.001). There was no significant difference in the diagnosis rates in the colonic region. These results indicated that diagnosis in < or = N3 was more accurate than that in > or = N2. There were 5 false-negative cases. All of the false-negative lymph nodes were located adjacent to the colonic wall. CONCLUSIONS: Intra-operative diagnosis of the positivity of < or = N2 lymph nodes was too poor to decide the extent of lymph node dissection of < D2. It is adequate to dissect according to at least the D2 criteria in all cases. If the surgeon observes N3 involvement, he should add the D3 dissection.

Cadmium accumulation in rats treated orally with cadmium chloride for 8 months.

To investigate the accumulation pattern of cadmium (Cd) in the liver and kidney following Cd intake from diet, female SD rats were fed cadmium chloride (CdCl2)- contained diets (1.24 and 4.96 ppm Cd) for 2 or 4 months. The other rats were fed CdCl2-contained diets (8, 40, 200, and 600 ppm Cd) for 2, 4 or 8 months. The control rats were given diet without Cd addition (lower than 0.01 ppm Cd). The concentrations of Cd in the liver and kidney derived from all rats were determined. The concentrations of Cd in the liver and kidney increased depending on the dosage of Cd. The concentrations of Cd in the liver did not reach plateau level even in the 200 and 600 ppm groups. On the other hand, the concentrations of Cd in the kidney in the 200 and 600 ppm groups reached a plateau level, which was approximately 250 micrograms/g. In the 600 ppm group, the concentrations of Cd in the kidney reached 250 micrograms/g at 2 months, but did not exceed that level at 4 months. In the 200 ppm group, the concentrations of Cd in the kidney increased to nearly the level of 250 micrograms/g at 8 months. The ratio of the concentrations of Cd in the kidney versus liver decreased as the dosage of Cd increased, suggesting that a low dosage of Cd was distributed preferentially to the kidney, but a high dosage of Cd was distributed to the liver. The relation curves between total amounts of Cd intake and Cd levels in the kidney in the 2-, 4-, and 8-month groups showed a parabola. The curves were shifted in parallel in the direction of higher levels of ingested Cd in order of length of Cd exposure period. These results suggested that when Cd is ingested over a long time at low concentrations, the amount of Cd accumulation in the kidney is small even for equal amounts of total ingested Cd.

Relationship between toxicity and cadmium accumulation in rats given low amounts of cadmium chloride or cadmium-polluted rice for 22 months.

To clarify toxic effects of long-term oral administration of low dose cadmium (Cd) on the liver and kidney, six groups of female Sprague-Dawley rats were fed a diet containing Cd-polluted rice or CdCl2 at concentrations up to 40 ppm, and killed after 12, 18, and 22 months. With toxicological parameters, including histopathology, there was no evidence of Cd-related hepato-renal toxicity, despite a slight decrease of mean corpuscular volume and mean corpuscular hemoglobin of red blood cells with 40 ppm CdCl2. Dose-dependent accumulation of Cd was observed in the liver and kidneys with peak levels of 130 +/- 42 micrograms/g and 120 +/- 20 micrograms/g, respectively, at 18 months in animals treated with 40 ppm CdCl2. A dose-dependent increase in urinary Cd levels became evident with time. Induction of metallothionein (MT) was also observed in the liver and kidney with a high correlation to the corresponding Cd levels. In the proximal renal tubular epithelia of 40 ppm CdCl2-treated rats at 22 months, prominent accumulation of Cd was observed in secondary lysosomes associated with MT deposits in their exocytotic residual bodies. The results demonstrated that, in contrast to the case with high-dose Cd-administration, renal toxicity is not induced by long-term oral administration of low amounts of Cd, although tissue accumulation does occur. Possible protective mechanisms may be operating.