Characterization of the human and rat phospholemman (PLM) cDNAs and localization of the human PLM gene to chromosome 19q13.1

Previous reports have demonstrated that the phospholemman (PLM), a 72-residue plasma-membrane protein enriched in skeletal muscle and heart, is a major substrate phosphorylated in response to insulin and adrenergic stimulation. Here we describe the isolation and characterization of human and rat PLM cDNA from the heart. Both PLM proteins share significant nucleotide and amino acid sequence and structural similarities with the previously published canine PLM and, to a lesser degree, with Na+/K(+)-ATPase gamma subunit, Mat-8 protein, and CHIF protein. Despite the functional diversity, all these proteins are quite small and possess a single transmembrane domain. Human PLM appears to be a unique gene localized on chromosome 19q13.1. The PLM mRNA is widely distributed in human tissues, with the highest expression in skeletal muscle and heart, suggesting a functional role in muscle contraction. Like canine PLM, both human and rat PLM induce a hyperpolarization-activated chloride current when expressed in Xenopus oocytes. The high degree of sequence and functional conservation among the mammalian PLM proteins indicates that this gene is conserved throughout evolution.

Human methionine synthase. cDNA cloning, gene localization, and expression

Human cDNAs for methionine synthase (5-methyltetrahydrofolate:L-homocysteine S-transmethylase; EC 2.1.1. 13) have been isolated from fetal and adult liver and HepG2 libraries. The cDNAs span 7.2 kilobases (kb) and consist of a 394-base pair upstream untranslated region, a 3795-base pair open reading frame encoding a 1265-residue 140.3-kDa protein, and about 3 kb of 3' region. The deduced protein sequence shares 53 and 63% identity with the Escherichia coli and the presumptive Caenorhabditis elegans proteins, respectively, and contains all residues implicated in B12 binding to the E. coli protein. Several potential polymorphisms and a cryptic splice deletion were detected in the coding region of the cDNAs. A polymorphism that results in a D919G modification in the protein is fairly common in human DNA samples. Northern analyses of poly(A) mRNA indicated two major species of about 8 and 10 kb in human tissues and some minor, partially spliced species. mRNA levels were highest in the pancreas, skeletal muscle, and heart of the adult and in the kidney in the fetus and were low in adult liver. Genomic clones were isolated and the 5' region was analyzed. Exon 1 is preceded by a number of potential promoter sites, including an E box, CAAT boxes, and a GC box, but this region lacks a TATA element. The human methionine synthase gene was localized to chromosome region 1q42.3-43 by in situ hybridization.

Spectrophotometric determination of the cardioprotective drug GP531 in human plasma

A simple spectrophotometric assay has been developed for determining concentrations of the new cardioprotective agent, GP531, in human plasma. The method is adapted from the Bratton-Marshall assay (BMA) for the detection of primary aromatic amines. The assay can be used to measure plasma concentrations of the drug during i.v. infusion administration to patients. The limit of quantitation of the assay is 1 microgram/ml using a 0.8 ml sample ultrafiltrate of plasma. The colorimetric assay correlates well with a previously described high performance liquid chromatographic (HPLC) procedure.

Kainic acid-induced focal cortical seizure is associated with an increase of synaptophysin immunoreactivity in the cortex

Aberrant neural sprouting of mossy fiber terminals in the supragranular layer of dentate gyrus is consistently observed following seizures in an animal model of epilepsy. It is also observed in hippocampi taken from epileptic patients with hippocampal sclerosis. The aberrant neural sprouting with synaptic reorganization is one of the proposed cellular mechanisms underlying epileptogenesis. It is not known whether aberrant synaptogenesis can be induced in the cortex, as in hippocampus, by seizure activity. In this study, synaptic terminals in the cortex were measured after focal cortical seizures by a semiquantitative image analysis of synaptophysin immunoreactivity. Brief intracortical perfusion of kainic acid induced focal status epilepticus and destructive cortical lesions. Synaptophysin immunoreactivity was significantly increased in the area where kainic acid was perfused. The increase of synaptophysin immunoreactivity, indicating an increase of synaptogenesis, was observed at 2 and 4 weeks after focal cortical seizures. This result suggests that kainic acid-induced seizure activity is associated with long-lasting synaptogenesis in the cortex. Studies centering on the physiological consequences of aberrant synaptogenesis may lead to additional understanding of the mechanisms underlying cortical epileptogenesis.

A sensitive assay for the aminoimidazole-containing drug GP531 in plasma using liquid chromatography with amperometric electrochemical detection: a new class of electroactive compounds

Aminoimidazole-containing compounds have been found to be electroactive and can be detected by amperometric electrochemical detection (ECD) with a high degree of sensitivity. A liquid chromatography (LC) method using ECD was developed for measuring plasma concentrations of the aminoimidazole-containing drug GP531, a potent adenosine-regulating agent. Plasma samples were extracted with 2-propanol and analyzed by LC under isocratic conditions using a mobile phase of methanol-sodium phosphate (pH 6.3; 3.3 mM) (32:68, v/v). The potential of the glassy carbon working electrode was set at +800 mV. The limit of quantitation was 12.5 ng ml-1 of GP531 using 100 microliters of plasma. The method was used to define the pharmacokinetics of GP531 in monkey following i.v. administration.

Injury induces presenilin-1 gene expression in mouse brain

Information regarding the genetic factors and environmental conditions that influence presenilin-1 (PS-1) gene expression is essential for the elucidation of its pathophysiological role in Alzheimer's disease (AD). Previous in situ hybridization studies have demonstrated that neurons are the predominant cell type expressing PS-1 in the mammalian central nervous system (CNS) under physiological conditions. In this study, we examined the consequences of an experimentally induced focal injury on PS-1 gene expression in the mouse CNS. Physical lesions to white matter regions produced a robust increase in PS-1 gene expression in non-neuronal cells immediately surrounding the site of injury. These findings underscore the epidemiological evidence that implicate head injury as a risk factor for AD and suggest a possible role for PS-1 in this capacity.

Plasma interleukin-8 levels in patients with post-hepatitic cirrhosis: relationship to severity of liver disease, portal hypertension and hyperdynamic circulation

The present study investigated plasma levels of interleukin-8 (IL-8) in patients with post-hepatitic cirrhosis and correlated it with the severity of liver diseases and haemodynamic parameters. Plasma IL-8 levels were significantly higher in 57 post-hepatitic cirrhotic patients (7.5 +/- 1.8 pg/mL; P < 0.005) than those in 41 healthy subjects (2.0 +/- 0.2 pg/mL). Elevated (> 5 pg/mL) plasma IL-8 levels were found in up to 30% of cirrhotic patients. In cirrhotic patients, plasma IL-8 levels progressively increased in relation to the severity of liver dysfunction (4.5 +/- 1.0, 4.9 +/- 1.4 and 20.5 +/- 8.3 pg/mL for Pugh's class A, B and C, respectively; P < 0.005). A significant correlation was observed between plasma IL-8 levels and serum bilirubin levels (r = 0.72; P < 0.001). There were no differences in the hepatic venous pressure gradient (15.4 +/- 1.1 vs 15.1 +/- 0.9 mmHg; P > 0.05) and systemic vascular resistance (1119 +/- 118 vs 1199 +/- 54 dyn.s/cm5; P > 0.05) between cirrhotic patients with and without elevated plasma IL-8 levels. In addition, plasma IL-8 levels did not correlate with hepatic venous pressure gradient (r = 0.26; P > 0.05) and systemic vascular resistance (r = -0.24; P > 0.05). These results demonstrate that plasma IL-8 levels are increased in patients with post-hepatitic cirrhosis. The severity of liver cirrhosis is an important factor for the occurrence of enhanced IL-8 levels. IL-8 does not play a role in the hyperdynamic circulation observed in patients with post-hepatitic cirrhosis.

Widespread neuronal expression of the presenilin-1 early-onset Alzheimer's disease gene in the murine brain

Mutations in the presenilin-1 (S182) gene have been genetically linked to early-onset Alzheimer's disease. To clarify the underlying molecular mechanism through which presenilin-1 is involved in the pathogenesis of this neurodegenerative disorder, the regional and cellular transcription profile of this gene was characterized in primary cells isolated from the murine brain by Northern blot hybridization using digoxigenin-labeled riboprobes. Our results indicate that presenilin-1 mRNA transcripts are widely distributed throughout the adult mouse brain. Furthermore, immunohistochemical labeling of hybridized sections indicates that expression was predominantly localized to neuronal cells. Neurons in the hippocampus and cerebral cortex, which are severely compromised in Alzheimer's disease, showed prominent expression of presenilin-1. In contrast, white matter areas and endothelial cells do not appear to express presenilin-1 to detectable levels. presenilin-1 transcripts, however, are also present less frequently in certain nonneuronal cell populations such as ependymal cells in the choroid plexus. Analysis of primary cells isolated from murine brain supported the results obtained by in situ hybridization and showed that cultured primary neurons and astrocytes express presenilin-1. Overall, it appears that the pattern of presenilin-1 gene expression parallels that previously described for the amyloid precursor protein.

Portal hypertensive colopathy in patients with cirrhosis

BACKGROUND

Colonic vascular ectasias and colorectal varices have been observed in patients with cirrhosis. However, the pathogenesis of these vascular lesions has not been established.

METHODS

We enrolled 35 cirrhotic patients and 20 normal controls in this study. All received colonoscopic examinations and measurements of plasma glucagon levels. Portal pressure measurements were performed in all the cirrhotic patients.

RESULTS

Colonic vascular ectasias occurred more commonly in cirrhotic patients than in controls (17 of 35 versus 0 of 20; p = 0.009) and more commonly in cirrhotic patients with ascites than in those without (15 of 24 versus 2 of 11; p = 0.038). However, the presence of colonic vascular ectasias was not related to the hepatic venous pressure gradient or plasma glucagon levels. Colorectal varices also occurred more commonly in cirrhotic patients than in controls (16 of 35 versus of 1 of 20; p = 0.034), but the hepatic venous pressure gradient, plasma glucagon levels, and severity of cirrhosis were not related to the presence of colorectal varices.

CONCLUSIONS

Portal hypertension per se and increased plasma glucagon levels may not play an important role in the pathogenesis of colonic vascular ectasias or colorectal varices in patients with cirrhosis.

Usefulness of [18F]fluorodeoxyglucose positron emission tomography in pediatric epilepsy surgery

We sought to analyze our experience with pediatric epilepsy surgery patients to determine the place of [18F]fluorodeoxyglucose (FDG) positron emission tomography (FDG-PET) in the preoperative evaluation of such children relative to chronic invasive intracranial monitoring. Fifty-six children who received an interictal FDG-PET as part of a phase 1 epilepsy surgery evaluation were compared with 44 children who did not have this study in a retrospective analysis of 100 patients accrued over a 4-year period. There was no significant difference between the two groups of children in terms of age or follow-up or was there a significant difference between the FDG-PET group and the no-FDG-PET group in regard to the numbers of children who had surgery, the type of procedure done, whether chronic invasive intracranial monitoring was performed, or outcome. The hypometabolic area demonstrated on interictal FDG-PET was concordant with that of the epileptogenic zone as mapped out with ictal recordings from subdural electrodes in 2 of 13 patients in whom a complete data set was available for comparison. In the other 11 children there was either poor agreement between interictal FDG-PET and ictal electrocorticographic data or the interictal FDG-PET was normal in the face of an epileptogenic focus which was successfully mapped by invasive electrophysiologic techniques and excised. We conclude that one cannot exclude a child with intractable partial seizures from surgical consideration because the interictal FDG-PET is normal; nor is there sufficient correlation between the interictal hypometabolic area on FDG-PET and the epileptogenic zone in terms of anatomic location and size to justify forgoing chronic invasive intracranial monitoring in children with intractable partial seizures being evaluated for epilepsy surgery unless there is absolute concordance between all neuroimaging, clinical, and video-electroencephalographic data.

Reduction pathway of cis-5 unsaturated fatty acids in intact rat-liver and rat-heart mitochondria: assessment with stable-isotype-labelled substrates

Besides the conventional isomerase-mediated pathway, unsaturated fatty acids with old-numbered double bonds are also metabolized by reduction pathways with NADPH as cofactor. The relative contributions of these pathways were measured in intact rat-liver and rat-heart mitochondria with a novel stable isotope tracer technique. A mixture of equal amounts of unlabelled cis-5-enoyl-CoA and 13C4-labelled acyl-CoA of equal chain lengths was incubated with mitochondria. The isotope distribution of 3-hydroxy fatty acids produced from the first cycle of beta-oxidation was analysed with selected ion monitoring by gas chromatograph-mass spectrometer. 3-Hydroxy fatty acids produced from the reduction pathway of unsaturated fatty acids were unlabelled (m + 0) whereas those produced from saturated fatty acids were labelled (m + 4). The m + 0 content serves to indicate the extent of reduction pathway. Rotenone treatment was used to switch the pathway completely to reduction. The extent of m + 0 enrichment in untreated mitochondria normalized to the m + 0 enrichment of rotenone-treated mitochondria was the percentage of reduction pathway. With this technique, cis-4-decenoate was found to be metabolized completely by the reduction pathway in both liver and heart mitochondria. cis-5-Dodecenoate was metabolized essentially by the reduction pathway in liver mitochondria, but only to 75% in heart mitochondria. When the chain length was extended to cis-5-tetradecenoate, the reduction pathway in liver mitochondria decreased to 86% and that in heart mitochondria to 65%. The effects of carnitine, clofibrate and other conditions on the reduction pathway were also studied. Enrichments of the label on saturated fatty acids and 3-hydroxy fatty acids indicated that the major pathway of reduction was not by the direct reduction of the cis-5 double bond. Instead, it is most probably by a pathway that does not involve forming a reduced saturated fatty acid first.

Effect of octreotide on total effective vascular compliance in patients with posthepatitic cirrhosis

BACKGROUND/AIMS

This study aimed to evaluate the effect of octreotide on total effective vascular compliance, measured during rapid volume expansion, in patients with posthepatitic cirrhosis.

METHODS

Twenty-nine patients with posthepatitic cirrhosis were randomly assigned to receive a 100-micrograms/h infusion of octreotide after a 100-micrograms bolus (n = 15), or a placebo (n = 14). Hemodynamic measurements were recorded before and 30 min after drug administration. Thereafter, rapid volume expansion was performed in each patient and hemodynamic measurements were repeated immediately after volume expansion.

RESULTS

Before volume expansion, placebo administration did not affect any of the hemodynamic values, while the hepatic blood flow was significantly decreased following octreotide administration. After volume expansion, the hemodynamic changes were similar between patients receiving octreotide and the placebo. However, the increase in right atrial pressure from the beginning to the end of volume expansion was higher and the total effective vascular compliance was lower in patients receiving octreotide (+3.5 +/- 0.3 mmHg, p = 0.05 and 1.69 +/- 0.16 ml.mmHg-1.kg-1, p < 0.05) compared to patients receiving placebo (+2.5 +/- 0.3 mmHg, 2.60 +/- 0.34 ml.mmHg-1.kg-1).

CONCLUSIONS

The present study suggests that octreotide decreased total effective vascular compliance in patients with posthepatitic cirrhosis. It is possible that, in patients with posthepatitic cirrhosis, venoconstriction was induced following octreotide administration.

Prevalence of gastric ulcer in cirrhotic patients and its relation to portal hypertension

The prevalence of gastric ulcer and its relationship to the severity of cirrhosis and degree of portal hypertension was evaluated in 245 cirrhotic patients, and compared with 245 age- and sex-matched healthy subjects. Portal and systemic haemodynamic studies were performed in cirrhotic patients. The prevalence of gastric ulcer in cirrhotic patients was 20.8%, which was significantly higher than the 4.0% found in healthy controls. Using a multivariate logistic regression model, the hepatic venous pressure gradient was found to be the only predictor of the prevalence of gastric ulcer in cirrhotic patients to present with gastric ulcer. The hepatic venous pressure gradient was significantly higher in cirrhotic patients with gastric ulcer than in those without (17.3 +/- 4.4 vs 15.5 +/- 5.0 mmHg, P = 0.01). Other variables, including sex, smoking, cardiac output and severity or aetiology of cirrhosis did not show significant differences between the two patient groups. The prevalence of gastric ulcer in cirrhotic patients whose hepatic venous pressure gradient was below 12 mmHg (4.5%) was similar to that observed in the healthy controls (4.0%). However, when the hepatic venous pressure gradient was > 12 mmHg, the prevalence of gastric ulcer (24.4%) was significantly higher than that in control subjects. However, the incidence of gastric ulcer was not related to the degree of portal hypertension. In conclusion, the prevalence of gastric ulcer in cirrhotic patients was found to be significantly higher than in the age- and sex-matched healthy subjects. Portal hypertension with a hepatic venous pressure gradient > 12 mmHg may be an important factor contributing to the increased prevalence of gastric ulcer observed in patients with liver cirrhosis.

Long QT syndrome patients with mutations of the SCN5A and HERG genes have differential responses to Na+ channel blockade and to increases in heart rate. Implications for gene-specific therapy

BACKGROUND

The genes for the long QT syndrome (LQTS) linked to chromosomes 3 (LQT3) and 7 (LQT2) were identified as SCN5A, the cardiac Na+ channel gene, and as HERG, a K+ channel gene. These findings opened the possibility of attempting gene-specific control of ventricular repolarization. We tested the hypothesis that the QT interval would shorten more in LQT3 than in LQT2 patients in response to mexiletine and also in response to increases in heart rate.

METHODS AND RESULTS

Fifteen LQTS patients were studied. Six LQT3 and 7 LQT2 patients were treated with mexiletine, and its effects on QT and QTc were measured. Mexiletine significantly shortened the QT interval among LQT3 patients (QTc from 535 +/- 32 to 445 +/- 31 ms, P < .005) but not among LQT2 patients (QTc from 530 +/- 79 to 503 +/- 60 ms, P = NS). LQT3 patients (n = 7) shortened their QT interval in response to increases in heart rate much more than LQT2 patients (n = 4) and also more than 18 healthy control subjects (9.45 +/- 3.3 versus 3.95 +/- 1.97 and 2.83 +/- 1.33, P < .05; data expressed as percent reduction in QT per 100-ms shortening in RR). Among these patients, there is also a trend for LQT2 patients to have syncope or cardiac arrest under emotional or physical stress and for LQT3 patients to have cardiac events either at rest or during sleep.

CONCLUSIONS

This is the first study to demonstrate differential responses of LQTS patients to interventions targeted to their specific genetic defect. These findings also suggest that LQT3 patients may be more likely to benefit from Na+ channel blockers and from cardiac pacing because they would be at higher risk of arrhythmia at slow heart rates. Conversely, LQT2 patients may be at higher risk to develop syncope under stressful conditions because of the combined arrhythmogenic effect of catecholamines with the insufficient adaptation of their QT interval when heart rate increases.

Plasma endothelin levels in patients with cirrhosis and their relationships to the severity of cirrhosis and renal function

BACKGROUND/AIMS

Increased plasma endothelin levels have been reported in patients with cirrhosis. However, the relationship between plasma endothelin concentrations and hyperdynamic circulation or renal functions has not been documented.

METHODS

We measured the plasma endothelin-1 and endothelin-3 concentrations using radioimmunoassay in 96 patients with cirrhosis (Pugh's A in 26, Pugh's B in 45 and Pugh's C in 25) and compared these values to 56 age- and sex-matched healthy subjects. Systemic and portal hemodynamic measurements, effective renal plasma flow, creatinine clearance, plasma aldosterone concentration and plasma renin activity were recorded for each patient.

RESULTS

Plasma endothelin-1 and endothelin-3 levels were significantly increased in patients with cirrhosis compared to healthy subjects. Additionally, plasma endothelin-1 and endothelin-3 values were higher in patients with cirrhosis and ascites than in those without ascites. Moreover, plasma endothelin-1 levels increased in relation to the severity of cirrhosis. On the other hand, modest negative correlations were found between endothelin-1 and creatinine clearance or effective renal plasma flow.

CONCLUSIONS

Plasma endothelin-1 and endothelin-3 levels are increased in patients with cirrhosis compared to healthy subjects. The increase in plasma endothelin-1 levels is related at least in part to the severity of cirrhosis. Increased endothelin-1 levels may possibly contribute to renal dysfunction in patients with cirrhosis.

Prevalence of duodenal ulcer in cirrhotic patients and its relation to Helicobacter pylori and portal hypertension

BACKGROUND

The prevalence of duodenal ulcer increases in cirrhotic patients. However, the pathogenesis remains unclear.

METHODS

The prevalence of duodenal ulcer and their relationship to cirrhosis and portal hypertension were evaluated in 325 cirrhotic patients, and compared with 325 age- and sex-matched healthy subjects. Portal and systemic hemodynamic studies were performed in all cirrhotic patients. Histological examination of gastric antral mucosa for Helicobacter pylori (H. pylori) was performed in 16 cirrhotic patients with duodenal ulcer and in 34 cirrhotic patients without duodenal lesions.

RESULTS

The prevalence of duodenal ulcer in cirrhotic patients was 9.5% (31 out of 325), significantly higher than 4.0% (13 out of 325) in the healthy controls (p = 0.007), but was not related to the severity of liver cirrhosis. The positive rate of H. pylori was not different between cirrhotic patients with duodenal ulcer and those without duodenal lesions (9/16 vs. 18/34, p > 0.05). The hepatic venous pressure gradient was also not different between these groups (17.2 +/- 5.1 vs. 16.1 +/- 4.9 mmHg, p > 0.05). Other variables including sex, smoking, and etiology of cirrhosis did not show significant differences.

CONCLUSIONS

The prevalence of duodenal ulcer is significantly higher in cirrhotic patients than in the age- and sex-matched healthy subjects. The severity of cirrhosis, the presence of H. pylori or portal hypertension per se does not play an important role in the increased prevalence of duodenal ulcer in cirrhotic patients.

Haemodynamic effects of a combination of propranolol and clonidine in patients with post-hepatitic cirrhosis

The haemodynamic effects of a combination of propranolol and clonidine were evaluated in 20 patients with post-hepatitic cirrhosis. Haemodynamic measurements were taken before and 30 min after an intravenous injection of 0.1 mg/kg of propranolol. Thereafter, each patient was given an oral dose of 150 micrograms of clonidine and re-measured 60 min later. In this series, eight patients were defined as 'non-responders' (a decrease in hepatic venous pressure gradient of < 10%) after propranolol treatment. Of both the responders and non-responders, propranolol caused expected decreases in the cardiac index and heart rate while mean arterial pressure remained unchanged. Of the propranolol responders, a significant decrease in hepatic venous pressure gradient was observed. After the addition of clonidine, in both the responders and non-responders there was a further decrease in hepatic venous pressure gradient with a concurrent drop in mean arterial pressure, but cardiac index and heart rate remained unaltered. In conclusion, the combination of propranolol and clonidine in post-hepatitic cirrhotic patients enhanced the reduction of portal pressure achieved by propranolol alone. The beneficial effects of the combination of the two in the reduction of portal pressure appeared to be similar in both the propranolol responders and non-responders. However, the drop in mean arterial pressure following the addition of clonidine may be hazardous to cirrhotic patients.

Clinical utility of video-EEG monitoring

This study investigated the efficiency of simultaneous video-electroencephalography (EEG) monitoring in documenting paroxysmal events, the value in clinical diagnosis, and the effect on treatment. In this retrospective review, 230 children underwent this procedure between January, 1990 and December, 1992. The data demonstrated that video-EEG monitoring can be used as a daytime procedure with a high success rate (80%) in detecting and differentiating the nature of recurrent paroxysmal behaviors that have occurred on a daily basis. Video-EEG monitoring has a high diagnostic rate in differentiating seizure versus nonseizure events (70%), in classifying seizure types (88%), and in evaluating the candidacy for epilepsy surgery (64%). Video-EEG diagnosis resulted in an alteration of clinical management in 45% of patients. Continuous video-EEG monitoring is an efficient and valuable procedure in the diagnosis and management of paroxysmal disorders in children.

Comparison of metabolic fluxes of cis-5-enoyl-CoA and saturated acyl-CoA through the beta-oxidation pathway

The metabolic fluxes of cis-5-enoyl-CoAs through the beta-oxidation cycle were studied in solubilized rat liver mitochondrial samples and compared with saturated acyl-CoAs of equal chain length. These studies were accomplished using either spectrophotometric assay of enzyme activities and/or the analysis of metabolites and precursors using a gas chromatographic method after conversion of CoA esters into their free acids. Cis-5-enoyl-CoAs were dehydrogenated by acyl-CoA oxidase or acyl-CoA dehydrogenases at significantly lower rates (10-44%) than saturated acyl-CoAs. However, enoyl-CoA hydratase hydrated trans-2-cis-5-enoyl-CoA at a faster rate (at least 1.5-fold) than trans-2-enoyl-CoA. The combined activities of 3-hydroxyacyl-CoA dehydrogenase and 3-ketoacyl-CoA thiolase for 3-hydroxy-cis-5-enoyl-CoAs derived from cis-5-enoyl-CoAs were less than 40% of the activity for the corresponding 3-hydroxyacyl-CoAs prepared from saturated acyl-CoAs. Rat liver mitochondrial beta-oxidation enzymes were capable of metabolizing cis-5-enoyl-CoA via one cycle of beta-oxidation to cis-3-enoyl-CoA with two less carbons. However, the overall rates of one cycle of beta-oxidation, as determined with stable-isotope-labelled tracer, was only 15-25%, for cis-5-enoyl-CoA, of that for saturated acyl-CoA. In the presence of NADPH, the metabolism of cis-5-enoyl-CoAs was switched to the reduction pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

[Aging changes of the electro-physiological characteristics of hypothalamic neurons in culture]

The aging changes of the electrophysiological characteristics of the hypothalamic neurons cultured for 0-140 days were studied in neonatal SD rats by the intracellular microelectrode recording technique. The growth velocity of the neurites was used as an index to divide the living process of the neurons into three periods, i.e. recovering period, growth period and aging period. It was found that the time constant and the membrane capacitance reached a top value in the growth period and then decreased significantly in the aging period (P < 0.05, P < 0.01). In the recovering period, the membrane resistance reached the highest; and then decreased significantly in growth period but did not change significantly in the aging period. The amplitude of the membrane resting potential was about -30 - -60 mv and increased with the days in vitro (P < 0.05). The neurons could produce single or burst discharges. It appears that certain electrophysiological characteristics of the hypothalamic neurons in culture could characterize certain aging changes.

Isomerization of trans-2,delta 5-dienoyl-CoA's to delta 3,delta 5-dienoyl-CoA's in the beta-oxidation of delta 5-unsaturated fatty acids

The NADPH-dependent reduction pathway for the metabolism of delta 5-unsaturated fatty acids involves the isomerization of trans-2,delta 5-dienoyl-CoA, initially formed from the dehydrogenation of delta 5-enoyl-CoA, to isomeric delta 3,delta 5-dienoyl-CoA. The latter intermediates were then isomerized to trans-2,trans-4-dienoyl-CoA, which then follows the NADPH-dependent pathway mediated by 2,4-dienoyl-CoA reductase. The isomerization from trans-2,delta 5-dienoyl-CoA to delta 3,delta 5-dienoyl-CoA is catalyzed by delta 3,delta 2-enoyl-CoA isomerase. In this investigation, we identified the stereoisomers of delta 3,delta 5-dienoates that were formed in the reaction. Starting from trans-2,cis-5-decadienoyl-CoA, the isomerization produced cis-3,cis-5- and trans-3,cis-5-decadienoates. On the other hand, trans-2,trans-5-decadienoyl-CoA yielded cis-3,trans-5- and trans-3,trans-5-decadienoates. In addition to purified rat liver delta 3,delta 2-enoyl-CoA isomerase, acyl-CoA oxidase from Arthrobacter also catalyzed the isomerization from trans-2,cis-5-dienoyl-CoA. However, this acyl-CoA oxidase could not catalyze the similar isomerization of trans-2,trans-5-dienoyl-CoA. delta 3,delta 5-t-2,t-4-Dienoyl-CoA isomerase used cis-3,cis-5-, trans-3,cis-5-, and cis-3,trans-5-dienoyl-CoA's as substrates and converted them to trans-2,trans-4-dienoyl-CoA. In contrast, trans-3,trans-5-dienoyl-CoA was not a substrate for this isomerization. Extensive purification of acyl-CoA oxidase through column chromatography could not remove or diminish the isomerization activity associated with acyl-CoA oxidase. Acyl-CoA oxidases derived from Candida and rat liver also possess isomerization activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Temperature sensitive simian virus 40 large T antigen immortalization of murine odontoblast cell cultures: establishment of clonal odontoblast cell line

During tooth formation instructive epithelial-mesenchymal interactions result in the cytodifferentiation of ectomesenchymal cells into odontoblasts which produce the dentin extracellular matrix (DECM). The purpose of our study was to establish a stable murine odontoblast cell line by immortalization of odontoblasts using retrovirus transfection. In order to accomplish this goal, we utilized a previously characterized odontoblast monolayer cell culture system supportive of odontoblast cytodifferentiation from dental papilla mesenchyme (DPM), expression and secretion of a DECM and dentin biomineralization. First mandibular molars from E-18 Swiss Webster mice were dissected, the DPM isolated, and pulp cells dissociated. Pulp cells (5 x 10(5)/well) were plated as monolayers and grown in alpha-MEM supplemented with 10% FCS, 100 units/ml penicillin and streptomycin, 50 micrograms/ml ascorbic acid. Cultures were maintained for 6 days at 37 degrees C in a humidified atmosphere of 95% air and 5% CO2, with media changes every two days. Immortalization was performed using a recombinant defective retrovirus containing the temperature sensitive SV-40 large T antigen cDNA and the neomycin (G418) resistance gene recovered from CRE packaging cells. Cultures were infected for 24 h with CRE conditioned medium containing 8 micrograms/ml of polybrene, the media was replaced with selective media containing 300 micrograms/ml of G418, and the cultures incubated at 33 degrees C for one month with media changes every 3-5 days. Neomycin resistant cells were cloned by serial dilution to single cells in 96-well culture plates and grown in selection medium at 33 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Stepwise immortalization and transformation of adult human prostate epithelial cells by a combination of HPV-18 and v-Ki-ras

Recent investigations have shown the presence of ras gene mutations and human papillomavirus (HPV) DNA in prostate carcinomas. In the present study, secondary adult human prostatic epithelial cells, upon transfection with a plasmid containing the entire HPV-18 genome, acquired an indefinite life-span in culture but did not undergo malignant conversion. Subsequent infection of these immortalized cells with the Kirsten murine sarcoma virus, which contains an activated Ki-ras oncogene, induced morphological transformation that led to the acquisition of neoplastic properties. These findings demonstrate the malignant transformation of adult human prostate epithelial cells in culture by a combination of viral oncogenes and the successive roles of HPV infection and Ki-ras activation in a multistep process responsible for prostate carcinogenesis.

A distributed and interactive three-dimensional medical image system

Three-dimensional (3D) arrays of digital data representing spatial volumes arise in many scientific applications, such as computed tomography (CT) and magnetic resonance imaging (MRI) created by imaging a series of cross sections of human bodies in medical applications. In this article, a software system architecture, called DISCOVER (a Distributed Interactive Scientific COmputing and Visualization EnviRonment), which can take advantage of the power of parallel processing, is proposed and implemented for interactive visualization and manipulation of the 3D digital data. The surface-rendering and the volume-rendering algorithms are implemented. The same software program can be executed on several different hardware platforms. We also propose a new rendering algorithm, called volume-surface rendering, for medical applications. The algorithm enables users to visualize the external and internal structures of medical objects simultaneously. The network version of the DISCOVER, as it stands today, is in practical use in the Hospital of National Cheng Kung University in Taiwan for real clinical applications.

On the transport of a suspended particle in flow through the entrance region of a tube

The motion of a single, spherical particle, released at different radial positions at the inlet of the entrance region of a straight circular laminar flow tube (Re = 260), was studied theoretically. Radial migration of the particle, either toward the tube center or toward the tube wall, was predicted. Based on the hypothesis that the particle experienced a lift force which was produced by the vorticity in the boundary layer and a velocity difference between the center of the suspended particle and the fluid medium, an inertia-vorticity fluid dynamic model was formulated to analyze the particle radial motions. Computational flow dynamics (CFD) solutions obtained from a 9.8 mm diameter tube model included the resulting particle loci for three particle radii (a = 0.1 cm, 0.085 cm, 0.050 cm), with the particle entry at various radial positions. The computation also covered a range of different particle entry speeds. The results showed that the particle migrates toward the tube center if it lags behind the medium in the core region; otherwise, it migrates toward the tube wall. Additional flow experiments were conducted in a circular (2R = 10.2 mm), 300 mm long straight tube. A small polystyrene sphere (2a = 1.72 mm, density rho p = 1.014 g.cm-3) was released at the inlet (X = 0, eta/R = 0.48) with two dimesionless release velocities (omega p = 0, and omega p > 1.0). The recorded particle traces agree well with the computational model.

Purification and mechanism of delta 3,delta 5-t-2,t-4-dienoyl-CoA isomerase from rat liver

A new enzyme, i.e., delta 3,delta 5-t-2,t-4-dienoyl-CoA isomerase, required in the NADPH-dependent metabolic pathway of odd-numbered double bond, unsaturated fatty acids, was isolated and purified to apparent homogeneity from rat liver. In the oxidation of odd-numbered double bond, unsaturated fatty acids, stepwise beta-oxidation leads to cis-5-enoyl-CoA, which is then dehydrogenated and isomerized to delta 3,delta 5-dienoyl-CoA. delta 3,delta 5-t-2,t-4-Dienoyl-CoA isomerase converts delta 3,delta 5-dienoyl-CoA to trans-2,trans-4-dienoyl-CoA, which is a substrate for NADPH-dependent 2,4-dienoyl-CoA reductase. This enzyme was purified through Matrex gel red A, blue Sepharose, DEAE-cellulose, CM-cellulose, hydroxylapatite, and Sepharose CL6B column chromatography of an ammonium sulfate precipitated fraction (30-80%) of rat liver homogenate. A native molecular weight of 200,000 with four subunits of 55,000 each was determined. The isoelectric point was 6.5. This enzyme was located in mitochondria and was inducible by clofibrate treatment. Using delta 3,delta 5-decadienoyl-CoA, delta 3,delta 5-dodecadienoyl-CoA, and delta 3,delta 5-tetradecadienoyl-CoA as substrates, the Vmax ratio was 1:0.5:0.4 and the Km's were 10.9, 5.9, and 1.4 microM, respectively. The specific activity of purified enzyme was 7 units/mg using delta 3,delta 5-decadienoyl-CoA as substrate. The mechanism of isomerization was studied by deuterium labeling. Consistent with the deuterium labeling pattern of the products, the isomerization from trans-2,cis-5-dienoyl-CoA to trans-2,trans-4-dienoyl-CoA was a two-step process through an intermediate delta 3,delta 5-dienoyl-CoA.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytochrome P450 mediated metabolism of diazepam in human and rat: involvement of human CYP2C in N-demethylation in the substrate concentration-dependent manner

Metabolism of diazepam (DZP) was studied in vitro to clarify the involvement of different forms of hepatic cytochrome P450 (CYP) in rats, and humans of Japanese and Caucasian origin. Microsomal 3-hydroxylation was the major pathway of DZP metabolism in rats and was inhibited by anti-CYP3A antibodies. Purified CYP3As and CYP2C11 catalysed 3-hydroxylation and N-demethylation, respectively, in the reconstituted systems. The rates of both reactions in human liver microsomes depended on the substrate concentration: the rate of 3-hydroxylation was 3-4 times higher than N-demethylation at 0.2 mM; the two activities were essentially the same at a lower substrate concentration (0.02 mM). Inhibitions of the N-demethylation by anti-CYP2C antibody and S-mephenytoin also depended on the substrate concentration and was detectable only at a low substrate concentration. Kinetic studies revealed the presence of two distinct catalytic activities for the N-demethylation; low Km and low Vmax, and high Km and high Vmax. The former activity seems to be mediated by a CYP2C P450 form. On the other hand, DZP 3-hydroxylation was rather selectively catalysed by a CYP3A P450 at the low and high substrate concentrations. These results were consistent with the observation in vivo that DZP N-demethylation and S-mephenytoin 4'-hydroxylation are closely correlated in humans. These results also suggest that the apparent discrepancy on the role of CYP forms in DZP metabolism in vitro and in vivo may reside in the difference in substrate concentration.

Primary nasal melanoma with exclusive liver metastasis: a case report

A 50-year-old male presented with a nasal mass causing obstruction and bleeding. The initial biopsy indicated a malignant lymphoma but the subsequent biopsy diagnosed an undifferentiated carcinoma. However, histopathological study and immunohistochemical study, made a final diagnosis of nasal melanoma. Six months after the diagnosis, the patient developed exclusive liver metastasis. He responded to 1 course of intensive chemotherapy with 200 mg/m2 cisplatin and 5000 mg/m2 dacarbazine for 6 months. For patients with nasal cavity malignancy, the possibility of primary melanoma should be considered. Combination chemotherapy with intensive dose of cisplatin and dacarbazine may be a viable treatment regimen for nasal melanoma with liver metastasis.

Effects of myocardial fiber orientation on the electrical induction of ventricular fibrillation

Although many studies have documented the importance of myocardial fiber orientation in the generation and maintenance of reentrant arrhythmia, its role in the induction of reentry by a single strong premature stimulus is held to be minimal. To study the importance of fiber orientation on the mechanisms of ventricular vulnerability to single strong premature electrical stimulation, computerized mapping studies using 56 closely (2. 5-5 mm) spaced epicardial bipolar electrodes were performed on six open-chest dogs to determine the patterns of activation after the application of a single strong premature stimulus. In an additional three dogs, both epicardial and endocardial mapping studies were performed with closely spaced electrodes. The baseline driving stimulus (S1) and the premature stimulus (S2) were given to the same or different sites on the right ventricular epicardium. When the line connecting the S1 and S2 (the electrical axis of stimulation) was roughly parallel to the fiber orientation, the vast majority of the early sites were found to lie between the S1 and S2 sites, with none of the early sites occurring on the side of the S2 site opposite to the S1 site. At the onset of ventricular fibrillation, figure-eight reentry was easily demonstrated. In comparison, when the S1 and S2 were given to the same site, or when the electrical axis of stimulation was roughly perpendicular to the fiber orientation, the early sites could occur on all sides of the S2 site. In these instances, a figure-eight reentry was not present at the onset of ventricular fibrillation, although this pattern could develop after the first few beats. These findings indicate that myocardial fiber orientation is an important factor in determining the patterns of activation during the electrical induction of ventricular fibrillation.

[Early diagnosis and treatment of contralateral primary glaucoma associated with neovascular glaucoma]

The early diagnosis and treatment of contralateral primary glaucoma associated with neovascular glaucoma (NVG) are discussed. Treatment of the underlying disease of NVG and long term follow-up of both eyes are emphasized in order to prevent blindness in both eyes.

Hepatic microsomal tolbutamide hydroxylation in Japanese: in vitro evidence for rapid and slow metabolizers

Microsomal hydroxylation of tolbutamide in Japanese livers was studied in vitro to ascertain the enzyme catalysing this reaction. Rates of tolbutamide hydroxylation differed individually 33-fold and 42-fold at 0.1 mM and 2.4 mM tolbutamide concentrations, respectively, and were segregated into two groups, rapid and slow metabolizers. An antibody raised against P450 human-2 (a form of CYP2C9) strongly inhibited the hydroxylation in livers of rapid metabolizers but only weakly inhibited in the slow metabolizer. Kinetic experiments further demonstrated a clear distinction in tolbutamide hydroxylation between two groups; the mean of apparent Km values for tolbutamide was 0.25 mM (n = 3) in the rapid group and 2.58 mM (n = 2) in the slow, respectively. These data suggest that different enzymes are involved in the hydroxylation in both metabolizer groups. Furthermore, CYP2C9 produced by cDNA expression in yeasts, catalysed tolbutamide hydroxylation at rates similar to the rapid metabolizer group at both the 0.1 mM and 2.4 mM concentrations. The apparent Km value of the expressed protein for tolbutamide, 0.26 mM, was similar to that determined for the rapid group of microsomal samples. Clear correlations were observed between the rate of microsomal tolbutamide hydroxylation at 0.1 mM and CYP2C9 protein content or the rate of S-mephenytoin 4'-hydroxylation in human liver. These results indicate that considerable portions of microsomal tolbutamide hydroxylation are catalysed by CYP2C9 or the closely related form in the rapid metabolizers.

Neoplastic transformation of a human keratinocyte cell line by the v-fos oncogene

To analyze the role of the fos oncogene in the growth of human epithelial cells, we have transfected a non-tumorigenic human epidermal keratinocyte line (RHEK-1) immortalized by the Ad12-SV40 hybrid virus with a plasmid carrying the v-fos gene together with plasmid pSV2-neo which confers resistance to neomycin. Individual neomycin-resistant clones were isolated and characterized with respect to morphological alteration. Of 16 independent clones analyzed, two appeared morphologically transformed and formed foci in culture. Only the two clones with a transformed phenotype were found by Southern blot hybridization analysis to contain the transfected v-fos gene. These clones formed colonies in soft agar and induced tumors when transplanted into nude mice. Analysis of fos specific mRNA and protein demonstrated that the transfected v-fos gene was expressed in these two clonal lines. These findings suggest that expression of the v-fos gene might facilitate the process of neoplastic transformation of human epithelial cells in culture. This appears to represent the first demonstration of the transforming potential of the v-fos gene in human cells.

Pharmacokinetic characterization and tissue distribution of the new glucocorticoid soft drug loteprednol etabonate in rats and dogs

Loteprednol etabonate, a new glucocorticoid soft drug with a characteristic chloromethyl ester function in the 17 beta-position, is currently in the early phases of clinical development. As the basis for human trials, this study describes a new reversed-phase high-performance liquid chromatographic method for the determination of levels of drug in plasma and urine samples and assesses the pharmacokinetic properties of loteprednol etabonate in dogs and rats. Intravenous administration of loteprednol etabonate (5 mg/kg) to dogs revealed a terminal half-life of 2.8 h, a volume of distribution of 3.7 L/kg, and a total body clearance of 0.9 L/h/kg. Intact loteprednol etabonate was not detectable in the urine. After oral administration of the drug (5 mg/kg) to dogs, only metabolites, but no intact drug, were found in the plasma, an indication for a high first-pass effect. A pronounced binding of the drug to plasma protein (> 90%) and a high erythrocyte-buffer partition coefficient of 7.8 were determined in vitro. Preliminary information about tissue distribution and possible metabolic pathways were obtained in rats after oral administration of a 14C-labeled loteprednol etabonate suspension (5 mg/kg). pH-selective extraction into ethyl acetate revealed three distinguishable fractions: (1) a neutral lipophilic fraction, presumably intact drug, (2) an acidic, lipophilic fraction, and (3) a hydrophilic nonextractable fraction. Levels of intact drug and metabolites were highest in liver and kidney, whereas significantly lower levels were found in other investigated organs (lung, brain, heart).(ABSTRACT TRUNCATED AT 250 WORDS)

Maintenance of amelogenin gene expression by transformed epithelial cells of mouse enamel organ

Electroporation was used to introduce foreign genes into cells derived from the mouse enamel organ epithelia (EOE). Optimal conditions for this electroporation were established. The introduction of a plasmid construct bearing the coding region for the large T-antigen from polyoma virus into EOE cells permitted the establishment of a derivative cell line that has the following characteristics: (1) the cells could be passaged many times; (2) they expressed a keratin-containing cytoskeleton; and (3) approx. 60% of the cells expressed amelogenin, a tissue-specific gene product unique to ameloblasts. Potential uses for such a cell line include analysis of: (1) the upstream regulatory regions required for temporally and spatially restricted expression of amelogenin; (2) the post-translational modification of amelogenin in synchronized cells and (3) the organization and biomineralization of enamel extracellular matrix in monolayer culture.

Cytokine regulation of nerve growth factor-mediated cholinergic neurotrophic activity synthesized by astrocytes and fibroblasts

The neurotrophic activity of astrocytes and fibroblasts and its regulation by various cytokines were investigated. Astrocyte conditioned medium (ACM) enhanced the survival of neurons and the proliferation of astrocytes in embryonic cortical cultures grown in serum-free defined medium. However, these results were not affected by acidic fibroblast growth factor, interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF alpha), and transforming growth factor-beta 1. In contrast, ACM induced choline acetyltransferase expression in septal cholinergic neurons via nerve growth factor (NGF)-dependent and -independent mechanisms. However, neither acidic nor basic fibroblast growth factor is involved in this biological activity in ACM. The cytokines listed above mainly stimulate NGF-mediated cholinergic neurotrophic activity in ACM. A combination of IL-1 beta and TNF alpha significantly enhanced choline acetyltransferase activity in septal neurons co-cultured with astrocytes, and this effect was found to be mediated by NGF produced by activated astrocytes. Effects of astrocytes on GABAergic neurons were also examined. ACM was found to increase glutamate decarboxylase activity in neuronal cultures from septum in the presence of Ara-C. However, the cytokines did not enhance this activity in ACM. Moreover, a combination of IL-1 beta and TNF alpha had no effect on glutamate decarboxylase activity in septal neurons co-cultured with astrocytes. In a final set of experiments, cholinergic neurotrophic activity in skin-derived fibroblast conditioned medium (FCM) was examined. FCM was found to possess biological activity similar to that of ACM on septal neurons grown in serum-free defined medium with Ara-C. The cytokines also enhanced NGF-mediated cholinergic neurotrophic activity in FCM. Astrocytes and fibroblasts were found to possess NGF-type and non-NGF-type cholinergic neurotrophic activity, and various cytokines were found to regulate the NGF-type cholinergic neurotrophic activity in both types of cells. NGF produced by astrocytes and fibroblasts that are activated by cytokines is likely to be important for development and regeneration of NGF-sensitive neurons in the central and peripheral nervous systems.

Radioiodine-131 therapy for well-differentiated thyroid cancer--a quantitative radiation dosimetric approach: outcome and validation in 85 patients

For almost five decades, 131I treatment of thyroid cancer has been based empirically on administered activity rather than on actual radiation doses delivered. In 1983, we defined radiation dose thresholds for successful treatment. This report is concerned with the subsequent validation of those thresholds in 85 patients. The successful ablation of thyroid remnants occurred after a single initial 131I administration in 84% of inpatients and in 79% of outpatients when treatment was standardized to a radiation dose of at least 30,000 cGy (rad). Administered activities low enough to permit outpatient therapy could be used in 47% of the patients. Lymph node metastases were treated successfully in 74% of patients with a single administration of 131I calculated to deliver at least 8,500 cGy (rad). For athyrotic patients with nodal metastases only, success was achieved in 86% of patients at tumor doses of at least 14,000 cGy (rad). These success rates are equal to or better than those reported with empiric methods of 131I administration. The individualized treatment planning selectively allocates hospitalization and higher exposures to 131I to those patients who require them.

Overexpression of transforming growth factor-beta in transgenic mice carrying the human T-cell lymphotropic virus type I tax gene

Human T-cell lymphotropic virus type I (HTLV-I) has been associated with an adult form of T-cell leukemia as well as tropical spastic paraparesis, a neurodegenerative disease. Adult T-cell leukemia patients express high levels of the type 1 isoform of transforming growth factor-beta (TGF-beta 1), which is mediated by the effects of the HTLV-I Tax transactivator protein on the TGF-beta 1 promoter. To understand further the regulation of TGF-beta 1 expression by Tax, we examined its expression in transgenic mice carrying the HTLV-I tax gene. We show that tumors from these mice and other tissues, such as submaxillary glands and skeletal muscle, which express high levels of tax mRNA selectively express high levels of TGF-beta 1 mRNA and protein. Moreover, TGF-beta 1 significantly stimulated the incorporation of tritiated thymidine into one of three cell lines derived from neurofibromas of tax-transgenic mice, which suggests that the excessive production of TGF-beta 1 may play a role in tumorigenesis and that these mice may serve as a useful model for studying the biological effects of TGF-beta in vivo.

Hippocampal grafts into the intact brain induce epileptic patterns

Spontaneous hippocampal EEG activity and evoked field potentials were investigated in intact rats and in animals with fetal hippocampal grafts. Pieces of hippocampal grafts, derived from 15- to 16-day-old fetuses, were used to prepare cell suspensions and grafted directly into the intact hippocampus. Control animals received suspension grafts of the cerebellum derived from fetuses of identical age. Host hippocampal electrical patterns were monitored with chronic single electrodes or with a 16-microelectrode probe from 7 to 10 months after grafting. In contrast to previously reported high survival rates of fetal grafts in studies with damage to the host brain prior to grafting, survival of both hippocampal (60%) and cerebellar grafts (20%) was very poor in the intact hippocampus. In animals with cerebellar transplants or without surviving grafted neurons the electrical activity of the host hippocampus was indistinguishable from normal controls. In rats with hippocampal grafts short duration, large amplitude EEG spikes (up to 10 mV) were recorded, predominantly during immobility. When the EEG spikes (putative interictal spikes) were of large amplitude and contained population spikes, test evoked responses delivered to the perforant path were suppressed after the spontaneous events. In contrast, evoked responses were facilitated by interictal spikes without population spikes. The threshold of electrically induced afterdischarges did not differ significantly between groups of intact rats and animals with or without hippocampal grafts. However, in three rats with hippocampal grafts the evoked afterdischarges were associated with behavioral seizures. In two of these rats spontaneously occurring seizures were also observed. Synaptophysin-immunoreactivity demonstrated growth of the host mossy fibers into the graft.(ABSTRACT TRUNCATED AT 250 WORDS)

Cellular replacement therapy for neurologic disorders: potential of genetically engineered cells

Neural transplantation, a mode of cellular replacement, has been used as a therapeutic trial for Parkinson's disease. Studies indicate that tonic release of the metabolites from the graft that can be utilized by the host brain, is likely to be the major mechanism responsible for the therapeutic effect. The use of fetal tissue is complicated by ethical controversy and immunological incompatibility. Autografting adult tissue has not been successful mainly due to poor survival. Genetically engineered cells are promising alternative sources of donor cells. We have investigated the potential of primary skin fibroblasts as donor cells for intracerebral grafting. Primary skin fibroblasts survive in the brain and remain in situ. A number of genes (nerve growth factor, tyrosine hydroxylase, glutamic acid decarboxylase, and choline acetyltransferase) have been successfully introduced and expressed in the primary fibroblasts. The L-dopa-secreting primary fibroblasts exhibited a behavioral effect in a rat model of Parkinson's disease up to 8 weeks after being grafted into denervated striatum. Factors that can maximize gene transfer, transgene expression, and fibroblast survival in the brain make up the future direction of investigation.

Timing of flagellar gene expression in the Caulobacter cell cycle is determined by a transcriptional cascade of positive regulatory genes

The Caulobacter crescentus flagellar (fla) genes are organized in a regulatory hierarchy in which genes at each level are required for expression of those at the next lower level. To determine the role of this hierarchy in the timing of fla gene expression, we have examined the organization and cell cycle regulation of genes located in the hook gene cluster. As shown here, this cluster is organized into four multicistronic transcription units flaN, flbG, flaO, and flbF that contain fla genes plus a fifth transcription unit II.1 of unknown function. Transcription unit II.1 is regulated independently of the fla gene hierarchy, and it is expressed with a unique pattern of periodicity very late in the cell cycle. The flaN, flbG, and flaO operons are all transcribed periodically, and flaO, which is near the top of the hierarchy and required in trans for the activation of flaN and flbG operons, is expressed earlier in the cell cycle than the other two transcription units. We have shown that delaying flaO transcription by fusing it to the II.1 promoter also delayed the subsequent expression of the flbG operon and the 27- and 25-kDa flagellin genes that are at the bottom of the regulatory hierarchy. Thus, the sequence and timing of fla gene expression in the cell cycle are determined in large measure by the positions of these genes in the regulatory hierarchy. These results also suggest that periodic transcription is a general feature of fla gene expression in C. crescentus.

Cloning, expression, and characterization of the Escherichia coli K-12 rfaD gene

The rfaD gene encodes ADP-L-glycero-D-mannoheptose-6-epimerase, an enzyme required for the biosynthesis of the lipopolysaccharide precursor ADP-L-glycerol-D-mannoheptose. The precise localization of the rfaD gene on a 1.3-kilobase SspI-HpaI fragment is reported. The rfaD gene and the flanking regions were completely sequenced. The location of the rfaD gene on the physical map of the Escherichia coli chromosome was determined. Primer extension studies were used to define the regulatory region of the rfaD gene. The cloned rfaD gene directed the synthesis of a 37,000-dalton polypeptide in several in vivo and in vitro expression systems. N-terminal analysis of purified ADP-L-glycero-D-mannoheptose-6-epimerase confirmed the first 34-amino-acid sequence deduced from the nucleotide sequence of the rfaD gene coding region. The primary structure of the rfaD protein contains the sequence fingerprint for the ADP-binding beta alpha beta fold at the N terminus.

Biochemical and radiohistochemical analyses of alpha-2 adrenergic receptors in the kindling model of epilepsy

Biochemical and radiohistochemical methods were used to study alterations in alpha-2 adrenergic receptors in the kindling model of epilepsy. The radioligands used for antagonist and agonist binding were [3H]idazoxan and [3H]p-aminoclonidine, respectively. Radioligand binding to membranes isolated from eight brain regions disclosed a small (14%) but statistically significant reduction in [3H]idazoxan binding in a single area, amygdala-pyriform-entorhinal cortex. This was confirmed by a larger (25%) reduction (P less than .02) in agonist binding in the same region. These reductions were present in animals sacrificed 1 day, but not 2 weeks, after the last kindled seizure. Quantitative radiohistochemical studies identified a bilaterally symmetric reduction of approximately 20% of [3H]p-aminoclonidine binding in the pyriform cortex and the central, medial and lateral amygdaloid nuclei. No significant differences were detected in nine other structures. We propose that the reduction in alpha-2 receptor binding contributes in part to the reduced sensitivity of pyriform cortex neurons of kindled animals to the inhibitory effects of alpha 2 agonists. The reduced alpha-2-receptor binding may also underlie a transient attenuation of alpha-2 receptor-mediated neuro-transmission and thereby constitute one mechanism contributing to kindling development.

Spatial organization of physiological activity in the hippocampal region: relevance to memory formation

Based on a review of anatomical and physiological findings, we suggest that the hippocampus may be viewed as a positive feedback device (autoassociator), which is capable of modifying the activity of the neocortical neurons. We examine the three-dimensional organization of evoked and spontaneous physiological patterns of the hippocampus and suggest rules how these patterns emerge during different behaviors from a hard-wired structural network. The high spatial coherence of theta activity is due to an external pacemaker, while the high synchrony of population bursts underlying hippocampal sharp waves is explained by the similar probability of recruitment of neurons by the burst-initiator cells along the whole extent of the hippocampus. We suggest that the burst-initiator cells are a group of CA3 neurons whose excitability is increased by a transient potentiation action of the neocortical activity during theta-concurrent exploratory behaviors. We hypothesize that sharp wave-concurrent population bursts result in a highly synchronous hippocampal output, converging preferentially on those entorhinal neurons which were instrumental in the creation of the burst-initiator neurons. The feedback action of population activity thus provides a selective mechanism for potentiation of connections between information-carrying neurons in the hippocampus and entorhinal cortex. The state-dependent operations of the anatomical hardware also point to the importance and advantage of studying the physiological activity of the intact brain.

[Infections in the early postoperative period following keratoplasty--a report of seven cases]

Keratoplasty was performed on 3482 eyes from 1965 to 1986 in our hospital. Five eyes (0.14%) were infected in the early postoperative period. Two eyes had endophthalmitis. These seven eyes were operated on again and with local and systemic antibiotics treated as well. Followed up for 36 days to 7 years, six eyes remained safe (5 eyes transparent and 1 eye semi-transparent.) The visual acuity reached 0.3 in two eyes, 0.2 in one eye and finger counting to 0.1 in three eyes. The seventh eye was enucleated because of serious infection. Several factors of infection in the early postoperative period following keratoplasty, causative organisms, the relations between the types of operation in the early postoperative period following keratoplasty were also discussed.

[Determination of the release of drugs from transdermal therapeutic systems. Presentation of a new release system]

A relatively simple release model for transdermal therapeutic systems (TTS) is described. The TTS is separated from the elution solvent by a semipermeable membrane. The elution solvent passes an elution channel with a flow rate of 3-9 ml/h. For the quantitative determination of the drug HPLC or UV spectrometry are used. Depending on the active drug and the design of the TTS, different releasing kinetics are observed. While diclofenac follows approximately a zero order kinetic, the respective kinetic for mepindolol roughly follows a diffusion controlled square root of t-order.

[Human pharmacologic studies on transdermal administration of mepindolol. Pharmacodynamic and orienting pharmacokinetics]

The pharmacodynamic effects of acute and repeated application of a transdermal patch (BIO TSD) containing 20 mg of the beta-receptor blocking agent mepindolol were assessed in 13 normotensive male volunteers. Orienting measurements of mepindolol serum levels were performed additionally. At rest, the effects on blood pressure and heart rate were very limited. However, during submaximum ergometer exercise, significant systemic beta-blocking effects were observed, especially after 5 days treatment. Repeated administration did not induce tachyphylaxis but resulted in an enhanced efficacy. The mepindolol serum concentrations were markedly lower than those measured after oral application of the drug. No systemic or local adverse reactions nor any relevant changes in laboratory parameters were observed.

Effects of intranigral application of clinically-effective anticonvulsants on electroshock-induced seizures

The authors sought to determine whether focal application of clinically-effective anticonvulsants to the substantia nigra produced anticonvulsant effects. To this end, the effects of phenobarbital, carbamazepine and phenytoin were examined on the electroshock seizure model in rats. Anticonvulsant efficacy was assessed by measuring the duration of tonic hindlimb extension before and after injection. It was found that application of phenobarbital into the nigra produced behavioral stereotypy and suppressed tonic hindlimb extension in a dose-dependent manner. These effects were spatially specific to the substantia nigra. By contrast, application of phenytoin or carbamazepine to the nigra produced neither anticonvulsant effects nor behavioral changes. Direct measurement of phenobarbital and carbamazepine in the substantia nigra showed that differences in concentration in the substantia nigra did not account for the lack of efficacy of carbamazepine. Moreover, concentrations of phenobarbital in the nigra after effective injection into the nigra exceeded concentrations in the nigra after effective systemic injections, by tenfold. Taken together, these data provide no compelling evidence that an action of the substantia nigra alone is sufficient to explain the therapeutic action of clinically-useful anticonvulsants.

An algorithm for three-dimensional visualization of radiation therapy beams

A computer algorithm to display radiation beams superimposed on three-dimensional (3-D) views of patient anatomy has been developed. It may be implemented as a postprocessing step to existing software for 3-D presentation and display. The algorithm takes as input a shaded 3-D view (reconstructed, for example, from computed tomography scans), together with the associated depth map, and generates as output an enhanced 3-D view highlighting in color the visible points which lie within the projected beam outlines. The algorithm is independent of the method used to generate the 3-D view (surface or volume rendering techniques may be used) and is independent of beam shape (beams may be modified with shielding blocks). It is not restricted to external surfaces and will correctly show radiation beams projected onto cut-away views of internal organs. The method is illustrated by application to a tangential pair for breast malignancy, using 3-D views generated with volume rendering software.

Microinjection of a benzodiazepine into substantia nigra elevates kindled seizure threshold

The purpose of these experiments was to initiate investigations of the brain site(s) at which the benzodiazepines exert their anticonvulsant effect. We examined the effects of microinjections of clonazepam into substantia nigra (SN) on seizure threshold in the kindling model. We also examined the distribution of microinjected [3H]methylclonazepam with autoradiographic methods. Microinjection of clonazepam bilaterally into substantia nigra pars reticulata (SNR), but not nearby, produced a 75% elevation of generalized seizure threshold. Quantitative analysis of autoradiographic studies indicated that the vast majority of [3H]methylclonazepam was distributed within 400 micron of the injection cannula tip; even optimally placed injections did not result in drug access throughout the entire SN. The data demonstrate that local application of an anticonvulsant benzodiazepine to the substantia nigra alone is sufficient to suppress seizures. We suggest that the substantia nigra is one site at which systemically administered benzodiazepines act to suppress seizures.

A set of positively regulated flagellar gene promoters in Caulobacter crescentus with sequence homology to the nif gene promoters of Klebsiella pneumoniae

The study reported here describes nuclease S1 mapping of the in-vivo transcription start sites of transcription units I and III of the hook gene cluster of Caulobacter crescentus. We show that transcription units I and II of this flagellar (fla) gene cluster, which have divergent promoters with transcription start sites separated by 218 nucleotides, are under positive transcriptional control by genes in transcription unit III. The promoters of transcription units I, II, and III were compared with flagellin gene promoters P25, P27 and P29 recently identified in C. crescentus. Promoters PII, P25, and P27, which are under positive regulation by transcription units III to V have strongly conserved sequence elements at -13 and -24 with the consensus sequence (C/T)TGGC(C/G)C-N5-TTGC. The -13, -24 sequence elements are not well conserved in promoter PI, but the promoter does contain a copy of the -13 and -24 consensus sequence 23 base-pairs upstream (PI). The C. crescentus fla gene promoters are not homologous to the canonical Escherichia coli -10, -35 promoter sequence, but they are very similar to the -12, -24 nif gene promoter sequence reported for Klebsiella pneumoniae and Rhizobium sp. The four positively regulated fla gene promoters examined here also share a third conserved element designated II-1, with the consensus sequence C-C-CGGC--AAA--GC-G, located at approximately -100. We speculate that the conserved sequence elements mapping at -13, -24 and -100 are cis-acting regulatory elements required for the transcription and periodic regulation of these fla genes in the C. crescentus cell cycle.