Cerebral white matter is highly vulnerable to ischemia

BACKGROUND AND PURPOSE

The effects of ischemia on the cerebral white matter structure seldom have been studied possibly because white matter is generally considered less vulnerable to ischemia than gray matter. The objective of this study was to evaluate the early (< or = 24 hours) structural effects of experimental focal ischemia on the cerebral white matter of the rat as a preliminary step to investigating human conditions of unknown pathogenesis that are characterized by selective damage to the white matter.

METHODS

Twenty-eight rats, including four controls, had a middle cerebral artery occluded with an intravascular filament for periods ranging between 0.5 and 24 hours. Brain samples from the subcortical white matter were examined with light and electron microscopic methods, and the abnormalities were quantified with an image-analysis system.

RESULTS

As early as 30 minutes after the arterial occlusion, there was conspicuous swelling of oligodendrocytes and astrocytes; after 3 hours, large numbers of oligodendrocytes were lethally injured. These changes preceded by several hours the appearance of necrotic neurons in the cortex and basal ganglia. Vacuolation and pallor of the white matter were very marked after 24 hours and reflected the segmental swelling of myelinated axons, the formation of spaces between myelin sheaths and axolemma and astrocyte swelling.

CONCLUSIONS

These results suggest that the cerebral white matter is highly vulnerable to the effects of focal ischemia. Pathological changes in oligodendrocytes and myelinated axons appear early and seem to be concomitant with, but independent of neuronal perikaryal injury. Modifications of this experimental model of focal ischemia could provide the means to test the hypothesis that selected types of human leukoencephalopathies have an ischemic origin.

Antimicrobial activity of plant essential oils using food model media: efficacy, synergistic potential and interactions with food components

The aim of this study was to optimise the antimicrobial efficacy of plant essential oils (EOs) for control of Listeria spp. and spoilage bacteria using food model media based on lettuce, meat and milk. The EOs evaluated were lemon balm, marjoram, oregano and thyme and their minimum inhibitory concentrations (MIC) were determined against Enterobacter spp., Listeria spp., Lactobacillus spp., and Pseudomonas spp. using the agar dilution method and/or the absorbance based microplate assay. MICs were significantly lower in lettuce and beef media than in TSB. Listeria strains were more sensitive than spoilage bacteria, and oregano and thyme were the most active EOs. EO combinations were investigated using the checkerboard method and Oregano combined with thyme had additive effects against spoilage organisms. Combining lemon balm with thyme yielded additive activity against Listeria strains. The effect of simple sugars and pH on antimicrobial efficacy of oregano and thyme was assessed in a beef extract and tomato serum model media. EOs retained greater efficacy at pH 5 and 2.32% sugar, but sugar concentrations above 5% did not negatively impact EO efficacy. In addition to proven antimicrobial efficacy, careful selection and investigation of EOs appropriate to the sensory profile of foods and composition of the food system is required. This work shows that EOs might be more effective against food-borne pathogens and spoilage bacteria when applied to foods containing a high protein level at acidic pH, as well as moderate levels of simple sugars.

Secretoneurin--a neuropeptide generated in brain, adrenal medulla and other endocrine tissues by proteolytic processing of secretogranin II (chromogranin C)

Secretogranin II (chromogranin C), originally described as tyrosine sulfated protein of the anterior pituitary, is present in large dense core vesicles of several endocrine cells and neurons. We raised antisera in rabbits to conjugates of two synthetic peptides (bovine secretogranin 133-151 and rat secretogranin 154-186) flanked in the primary structure of secretogranin II by pairs of basic residues and used them to investigate the proteolytic processing of this protein by immunoblotting and a newly developed radioimmunoassay. The sensitivity of this assay was 30 fmol for secretogranin 154-186 and 60 fmol for secretogranin 133-151. The highest degree of processing of secretogranin II (> 90%) occurs in brain. One of the peptides (secretogranin 133-151) is not generated to any significant extent. The other peptide, secretogranin 154-186, however, is formed in vivo, and in brain the free peptide apparently represents the predominant form. The highest concentrations of secretogranin 154-186 are found in the hypothalamus, two- to six-fold lower levels are present in the hippocampus, caudate nucleus, thalamus and brainstem. These concentrations are comparable to those of established neuropeptides. In order to indicate the special relevance of secretogranin II and of this peptide for brain we have named this peptide secretoneurin. The newly developed radioimmunoassay for this peptide will be a useful tool to establish its physiologic role in brain.

Higher risk of preterm birth and low birth weight in women with periodontal disease

Pregnant women with periodontal disease (PD) may be at increased risk for having preterm low-birth-weight (PLBW) children. We investigated whether the maintenance of the mothers' periodontal health after 28 weeks' gestation reduces the risk of PLBW. Of the 639 women studied, 406 had gingivitis and received treatment before 28 weeks' gestation, and 233 had PD and were treated after delivery. Data about previous and current pregnancies and known risk factors were obtained from patients' medical records. Primary outcomes were delivery before 37 weeks' gestation or an infant with birth weight below 2500 g. The incidence of PLBW was 2.5% in periodontally healthy women, and 8.6% in women with PD (p = 0.0004, relative risk = 3.5, 95% CI, 1.7 to 7.3). Risk factors significantly associated with PLBW were previous PLBW, PD, fewer than 6 pre-natal visits, and low maternal weight gain. PD was associated with both preterm birth and low birth weight, independent of other risk factors.

Comparison of the Mycobacteria Growth Indicator Tube (MGIT) with radiometric and solid culture for recovery of acid-fast bacilli

In a multicenter study involving three reference centers for mycobacteria, the rate of recovery of acid-fast bacilli (AFB) and the mean time to their detection from clinical specimens was determined by using the Mycobacteria Growth Indicator Tube (MGIT). These parameters were compared to those assessed by the radiometric BACTEC 460 TB system and by cultivation on solid media. Clinical specimens (n = 1,500) were pretreated with N-acetyl-L-cysteine (NALC)-NaOH. The contamination rates for MGITs were 2.0% (center 1), 13.8% (center 2), and 6.1% (center 3). A total of 180 mycobacterial isolates were detected (M. tuberculosis complex, n = 113; nontuberculous mycobacteria [NTM], n = 67). When using a combination of liquid and solid media (the current "gold standard" for culture), MGIT plus solid media detected 156 (86.7%) of the isolates, whereas BACTEC plus solid media recovered 168 (93.3%) of all AFB. Between these two gold standards there was no statistically significant difference (P > 0.05). The combination of MGIT plus BACTEC detected 171 (95.0%) of all isolates (compared with MGIT plus solid media, P < 0.01; compared with BACTEC plus solid media, P > 0.05). Considering the efficacies of the different media separately, MGIT was superior to solid media (although not significantly; P > 0.05) in detecting AFB but was inferior to the BACTEC system (P < 0.01). The mean time to the detection of M. tuberculosis complex was 9.9 days with MGIT, 9.7 days with BACTEC, and 20.2 days with solid media. NTM needed, on average, 11.9, 13.0, and 22.2 days to appear by the three methods, respectively. In conclusion, MGIT proved to be a valuable alternative to the radiometric cultivation system.

Species-wide homogeneity of nuclear ribosomal ITS2 sequences in the spider mite Tetranychus urticae contrasts with extensive mitochondrial COI polymorphism

We compared patterns of intraspecific polymorphism of two markers with contrasted modes of evolution, nuclear ribosomal DNA (rDNA) and mitochondrial DNA (mtDNA), in the phytophagous mite Tetranychus urticae Koch. The second internal transcribed spacer (ITS2) of rDNA and a fragment in the mtDNA gene coding for Cytochrome Oxidase I (COI), were PCR-amplified and sequenced in samples of various geographical origins distributed worldwide. The 15 COI haplotypes found fell into two major phylogenetic lineages differing by an average of 5% nucleotide divergence. Samples from the Mediterranean basin were represented in both lineages, and showed no phylogeographical structure. The other samples, from temperate regions of the northern hemisphere, were clustered in one of the lineages and displayed little variation, indicating a recent colonization of this region. In contrast, no variation at all was found at the ITS2 in this species. We sequenced both COI and ITS2 in four other species of the genus Tetranychus and found that, despite the absence of intraspecific polymorphism, ITS appears to evolve 2.5 times faster than COI. We argue that rDNA homogeneity over the species range of T. urticae results from the high colonization potential of this species, preventing long-term differentiation. Preliminary data on two other mite species (Amphitetranychus viennensis Zacher and Mononychellus progresivus Doreste) with stricter ecological requirements and more restricted colonization potential revealed substantial and concordant geographical differentiation for both ITS2 and COI.

Loss of DAL-1, a protein 4.1-related tumor suppressor, is an important early event in the pathogenesis of meningiomas

Meningiomas are common nervous system tumors, whose molecular pathogenesis is poorly understood. To date, the most frequent genetic alteration detected in these tumors is loss of heterozygosity (LOH) on chromosome 22q. This finding led to the identification of the neurofibromatosis 2 (NF2) tumor suppressor gene on 22q12, which is inactivated in 40% of sporadic meningiomas. The NF2 gene product, merlin (or schwannomin), is a member of the protein 4.1 family of membrane-associated proteins, which also includes ezrin, radixin and moesin. Recently, we identified another protein 4.1 gene, DAL-1 (differentially expressed in adenocarcinoma of the lung) located on chromosome 18p11.3, which is lost in approximately 60% of non-small cell lung carcinomas, and exhibits growth-suppressing properties in lung cancer cell lines. Given the homology between DAL-1 and NF2 and the identification of significant LOH in the region of DAL-1 in lung, breast and brain tumors, we investigated the possibility that loss of expression of DAL-1 was important for meningioma development. In this report, we demonstrate DAL-1 loss in 60% of sporadic meningiomas using LOH, RT-PCR, western blot and immunohistochemistry analyses. Analogous to merlin, we show that DAL-1 loss is an early event in meningioma tumorigenesis, suggesting that these two protein 4.1 family members are critical growth regulators in the pathogenesis of meningiomas. Furthermore, our work supports the emerging notion that membrane-associated alterations are important in the early stages of neoplastic transformation and the study of such alterations may elucidate the mechanism of tumorigenesis shared by other tumor types.

TVB-2640 (FASN Inhibitor) for the Treatment of Nonalcoholic Steatohepatitis: FASCINATE-1, a Randomized, Placebo-Controlled Phase 2a Trial

BACKGROUND & AIMS

Increased de novo lipogenesis creates excess intrahepatic fat and lipotoxins, propagating liver damage in nonalcoholic steatohepatitis. TVB-2640, a fatty acid synthase inhibitor, was designed to reduce excess liver fat and directly inhibit inflammatory and fibrogenic pathways. We assessed the safety and efficacy of TVB-2640 in patients with nonalcoholic steatohepatitis in the United States.

METHODS

3V2640-CLIN-005 (FASCINATE-1) was a randomized, placebo-controlled, single-blind study at 10 US sites. Adults with ≥8% liver fat, assessed by magnetic resonance imaging proton density fat fraction, and evidence of liver fibrosis by magnetic resonance elastography ≥2.5 kPa or liver biopsy were eligible. Ninety-nine patients were randomized to receive placebo or 25 mg or 50 mg of TVB-2640 (orally, once-daily for 12 weeks). The primary end points of this study were safety and relative change in liver fat after treatment.

RESULTS

Liver fat increased in the placebo cohort by 4.5% relative to baseline; in contrast TVB-2640 reduced liver fat by 9.6% in the 25-mg cohort (n = 30; least squares mean: -15.5%; 95% confidence interval, -31.3 to -0.23; P = .053), and 28.1% in the 50-mg cohort (n = 28; least squares mean: -28.0%; 95% confidence interval, -44.5 to -11.6; P = .001). Eleven percent of patients in the placebo group achieved a ≥30% relative reduction of liver fat compared to 23% in the 25-mg group, and 61% in the 50-mg group (P < .001). Secondary analyses showed improvements of metabolic, pro-inflammatory and fibrotic markers. TVB-2640 was well tolerated; adverse events were mostly mild and balanced among the groups.

CONCLUSIONS

TVB-2640 significantly reduced liver fat and improved biochemical, inflammatory, and fibrotic biomarkers after 12 weeks, in a dose-dependent manner in patients with nonalcoholic steatohepatitis. ClinicalTrials.gov, Number NCT03938246.

Glucokinase is highly induced and glucose-6-phosphatase poorly repressed in liver of rainbow trout (Oncorhynchus mykiss) by a single meal with glucose

The low dietary starch utilisation by rainbow trout (Oncorhynchus mykiss) may be attributed to a dysfunction of the nutritional regulation of the hepatic glucose/glucose-6-phosphate cycle. The present study was initiated to analyse the regulation of activity and gene expression of hepatic glucokinase (GK) and glucose-6-phosphatase (G6Pase) by dietary carbohydrates in this species. We found that even a single meal containing 24% of glucose is sufficient to induce the GK expression (mRNA and activity) as in mammals. In contrast, although the inhibitory effect of dietary glucose on G6Pase expression is observed at the molecular level, the G6Pase activity is not significantly inhibited by dietary glucose. Thus, in contrast to the gluconeogenic G6Pase enzyme, a rapid adaptation of the hepatic glycolytic GK enzyme to dietary glucose seems effective in rainbow trout. These results suggest that in carnivorous rainbow trout, the liver is capable to strongly regulate the utilisation of glucose but not the synthesis of glucose.

Incomplete infarct and delayed neuronal death after transient middle cerebral artery occlusion in rats

BACKGROUND AND PURPOSE

The clinical syndrome of transient ischemic attacks is accompanied in a significant percentage of patients by brain lesions or neuroimaging abnormalities whose structural counterparts have not been defined. The objective of this study was to analyze, in an experimental model of short-term (< 25 minutes) focal ischemia and long-term (< or = 28 days) reperfusion, the extent and nature of the structural abnormalities affecting neurons and glia located within the territory of the transiently occluded artery.

METHODS

Adult Wistar rats (n = 121) had the origin of one middle cerebral artery (MCA) occluded with a nylon monofilament for periods of 10 to 25 minutes. Experiments of transient MCA occlusion were terminated at variable periods ranging from 1 day to 4 weeks. Control experiments consisted of (1) MCA occlusion without reperfusion (n = 7) lasting 7 to 14 days and (2) sham operations (n = 2) followed by 1- to 4-day survival. After in situ fixation, brain specimens were serially sectioned and subjected to detailed morphometric evaluations utilizing light and electron microscopes. The statistical method used to evaluate the results was based on ANOVA followed by Bonferroni's corrected t test and Student's t test comparisons.

RESULTS

Brain lesions were not detectable in the sham-operated controls. All brains with permanent MCA occlusion (7 to 14 days) had large infarctions with abundant macrophage infiltration and early cavitation. Forty-five (37%) of the experiments involving transient MCA occlusion had no detectable brain lesions after 4 weeks. Selective neuronal necrosis was found in 76 of 121 rats (63%) with transient MCA occlusion. Neuronal necrosis always involved the striatum, and in 29% of the brains with ischemic injury, necrosis also included a short segment of the cortex. In the striatum, the length of the arterial occlusion was the main determinant of the number of necrotic neurons (20 minutes [22.6 +/- 19] is worse than 10 minutes [4.9 +/- 7]) (P < .0001). In the cortex, the length of reperfusion determined the number of necrotic neurons appearing in layer 3. Experiments with reperfusion of 4 to 7 days' duration yielded more necrotic neurons per microscopic field (2.02 +/- 3) than those lasting fewer days (0.04 +/- 0.1) (P < .05). The histological features of these lesions underwent continuous change until the end of the fourth week, at which time necrotic neurons were still visible both in the striatum and in the cortex.

CONCLUSIONS

Arterial occlusions of short duration (< 25 minutes) produced, in 76 of 121 experiments (63%), brain lesions characterized by selective neuronal necrosis and various glial responses (or incomplete infarction). This lesion is entirely different from the pannecrosis/cavitation typical of an infarction that appears 3 to 4 days after a prolonged arterial occlusion. Delayed neuronal necrosis, secondary to a transient arterial occlusion or increasing numbers of necrotic neurons in experiments with variable periods of reperfusion, was a response observed only at a predictable segment of the frontoparietal cortex.

Quantitative estimation of permeability surface-area product in astroglial brain tumors using perfusion CT and correlation with histopathologic grade

BACKGROUND AND PURPOSE

Glioma angiogenesis and its different hemodynamic features, which can be evaluated by using perfusion CT (PCT) imaging of the brain, have been correlated with the grade and the aggressiveness of gliomas. Our hypothesis was that quantitative estimation of permeability surface area product (PS), cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) in astroglial brain tumors by using PCT will correlate with glioma grade. High-grade gliomas will show higher PS and CBV as compared with low-grade gliomas.

MATERIALS AND METHODS

PCT was performed in 32 patients with previously untreated astroglial tumors (24 high-grade gliomas and 8 low-grade gliomas) by using a total acquisition time of 170 seconds. World Health Organization (WHO) glioma grades were compared with PCT parameter absolute values by using Student or nonparametric Wilcoxon 2-sample tests. Receiver operating characteristic (ROC) analyses were also done for each of the parameters.

RESULTS

The differences in PS, CBV, and CBF between the low- and high-grade tumor groups were statistically significant, with the low-grade group showing lower mean values than the high-grade group. ROC analyses showed that both CBV (C-statistic 0.930) and PS (C-statistic 0.927) were very similar to each other in differentiating low- and high-grade gliomas and had higher predictability compared with CBF and MTT. Within the high-grade group, differentiation of WHO grade III and IV gliomas was also possible by using PCT parameters, and PS showed the highest C-statistic value (0.926) for the ROC analyses in this regard.

CONCLUSIONS

Both PS and CBV showed strong association with glioma grading, high-grade gliomas showing higher PS and CBV as compared with low-grade gliomas. Perfusion parameters, especially PS, can also be used to differentiate WHO grade III from grade IV in the high-grade tumor group.

Daily rhythms of insulin and glucose levels in the plasma of sea bass Dicentrarchus labrax after experimental feeding

Significant and inverse circadian rhythms are demonstrated in glucose and plasma insulin in fish fed a natural diet. The highest glucose levels are found during the light period, around feeding time, and the insulin level peaks during the dark period. As a possible cause for the insulin rhythmicity, the daily variations in several plasma amino acids are considered. The feeding times could be a training factor for metabolic rhythms, which are maintained even during a fast of 7 days. The differences in the compositions of the diets could be responsible for the lack of circadian rhythms in fish fed on a commercial diet.

Influence of high donor serum sodium levels on early postoperative graft function in human liver transplantation: effect of correction of donor hypernatremia

Donor hypernatremia was reported to cause postoperative graft dysfunction in human orthotopic liver transplantation (OLT). However, the effects of the correction of donor hypernatremia before organ procurement have not been confirmed. The aim of this study is to determine whether donor hypernatremia is associated with early graft dysfunction after OLT and to determine the effect of the correction of donor hypernatremia. One hundred eighty-one consecutive OLTs performed between May 1997 and July 1998 were entered onto this study. The cases were divided into three groups according to the donor serum sodium concentration: group A, serum sodium of 155 mEq/L or less before organ procurement (n = 118); group B, peak sodium greater than 155 mEq/L and final sodium 155 mEq/L or less (n = 36); and group C, final sodium greater than 155 mEq/L (n = 27). Graft survival within 90 days after OLT and early postoperative graft function were analyzed. There were no significant differences in donor and recipient variables among the three groups. The frequencies of graft loss were 15 of 118 grafts (12.7%) in group A, 4 of 36 grafts (11.1%) in group B, and 9 of 27 grafts (33.3%; P <.05 v groups A and B) in group C. The liver enzyme values in groups B and C were significantly greater than those in group A postoperatively. The prothrombin times of group C were significantly longer than those of group A for the first 4 postoperative days. Recipients of hepatic allografts from donors with uncorrected hypernatremia had a significantly greater incidence of graft loss compared with recipients of hepatic allografts from normonatremic donors. However, the differences in graft survival were abrogated by the correction of donor hypernatremia before procurement.

Insertional mutagenesis and recovery of interrupted genes of Streptococcus mutans by using transposon Tn917: preliminary characterization of mutants displaying acid sensitivity and nutritional requirements

New vectors were constructed for efficient transposon Tn917-mediated mutagenesis of poorly transformable strains of Streptococcus mutans(pTV1-OK) and subsequent recovery of interrupted genes in Escherichia coli (pT21delta2TetM). In this report, we demonstrate the utility of Tn917 mutagenesis of a poorly transformable strain of S. mutans (JH1005) by showing (i) the conditional replication of pTV1-OK, a repA(Ts) derivative of the broad-host-range plasmid pWVO1 harboring Tn9l7, in JH1005 at the permissive temperature (30 degrees C) versus that at the nonpermissive temperature (45 degrees C); (ii) transposition frequencies similar to those reported for Bacillus subtilis (10(-5) to 10(-4)) with efficient plasmid curing in 90 to 97% of the erythromycin-resistant survivors following a temperature shift to 42 to 45 degrees C; and (iii) the apparent randomness of Tn917 insertion as determined by Southern hybridization analysis and the ability to isolate nutritional mutants, mutants in acid tolerance, and mutants in bacteriocin production, at frequencies ranging from 0.1 to 0.7%. Recovery of transposon-interrupted genes was achieved by two methods: (i) marker rescue in E. coli with the recovery vector pTV21delta2TetM, a tetracycline-resistant and ampicillin-sensitive Tn9l7-pBR322 hybrid, and (ii) "shotgun" cloning of genomic libraries of Tn917 mutants into pUC19. Sequence analyses revealed insertions at five different genetic loci in sequences displaying homologies to Clostridium spp.fhs (66% identity), E. coli dfp (43% identity), and B. subtilis ylxM-ffh (58% identity), icd (citC [69% identity]), and argD (61% identity). Insertions in icd and argD caused nutritional requirements; the one in ylxM-ffh caused acid sensitivity, while those in fhs and dfp caused both acid sensitivity and nutritional requirements. This paper describes the construction of pTV1-OK and demonstrates that it can be efficiently employed to deliver Tn917 into S. mutans for genetic analyses with some degree of randomness and that insertions in the chromosome can be easily recovered for subsequent characterization. This represents the first published report of successful Tn9l7 mutagenesis in the genus Streptococcus.

The hepatitis C virus alternate reading frame (ARF) and its family of novel products: the alternate reading frame protein/F-protein, the double-frameshift protein, and others

The hepatitis C virus (HCV) has an alternate reading frame (ARF) that overlaps the core protein gene. The overlapping reading frame distinguishes HCV from all of its known viral relatives, with the possible exception of GB virus B (GBV-B). The ARF is expressed during natural HCV infections and stimulates specific immune responses. Like several essential genes in other viruses (e.g., the human immunodeficiency virus polymerase) the ARF lacks an in-frame AUG start codon, suggesting that its expression involves unusual translation-level events. In vitro studies indicate that ribosomal frameshifting may be one of several processes that can lead to translation of the ARF. Frameshifting yields chimeric proteins that have segments encoded in the core gene covalently attached to amino acids encoded in the ARF. A consistent nomenclature for the ARF's protein products has yet to be established. We propose that all proteins that contain amino acids encoded in the + 1 ARF be called alternate reading frame proteins (ARFPs) and that specific ARFPs, such as the ARFP/F-protein, the double-frameshift protein, and the short form of core + 1, be designated as follows: ARFP/F (ARFP/F-protein), ARFP/DF (double-frameshift), and ARFP/S (short form of core + 1). The roles of ARFPs in the HCV life cycle are not yet known. There is a significant possibility that ARFPs may be responsible for some of the effects attributed to the core protein, given that most studies seeking to define the function of the core protein have employed materials likely to contain a combination of the core protein and ARFPs. The observed effects of the core protein include the induction of liver cancer, transformation of cells, and alterations of immune responses. This article reviews the discovery of ARF, describes the RNA structural elements involved in core/ARF gene expression, discusses possible functions of ARFPs, and considers the potential usefulness of ARFPs in vaccines. The HCV ARF is the focus of a new and rapidly expanding area of research, and the results of many ongoing studies are currently available in abstract form only. The preliminary nature of investigations that have not yet been reviewed by peers is noted in the text.

Genetic and biochemical analysis of mutacin 1140, a lantibiotic from Streptococcus mutans

Streptococcus mutans JH1000 and its derivatives were previously shown (J. D. Hillman, K. P. Johnson, and B. I. Yaphe, Infect. Immun. 44:141-144, 1984) to produce a low-molecular-weight, broad-spectrum bacteriocin-like inhibitory substance (BLIS). The thermosensitive vector pTV1-OK harboring Tn917 was used to isolate a BLIS-deficient mutant, DM25, and the mutated gene was recovered by shotgun cloning in Escherichia coli. Sequence analysis of insert DNA adjacent to Tn917 led to the identification of four open reading frames including two (lanA and lanB) which have substantial homology to the Staphylococcus epidermidis structural gene (epiA) and a modifying enzyme gene (epiB) for biosynthesis of the lantibiotic epidermin, respectively. Although the BLIS activity could not be recovered from broth cultures, high yields were obtained from a solid medium consisting of Todd-Hewitt broth containing 0.5% agarose that was stab inoculated with JH1140 (a spontaneous mutant of JH1000 that produces threefold-elevated amounts of activity). Agar could not substitute for agarose. Chloroform extraction of the spent medium produced a fraction which yielded two major bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The faster-migrating band was absent in chloroform extracts of the mutant, DM25. The amino acid sequence of this band was determined by Edman sequencing and mass spectroscopy. The results showed that it is a lantibiotic, which we have named mutacin 1140, and that the sequence corresponded to that deduced from the lanA sequence. We observed a number of similarities of mutacin 1140 to epidermin and an S. mutans lantibiotic, B-Ny266, but it appears to have significant differences in the positions of its thioether bridges. It also has other unique features with regard to its leader sequence and posttranslational modification. A proposed structure for mutacin 1140 is presented.

Identity of 4a-carbinolamine dehydratase, a component of the phenylalanine hydroxylation system, and DCoH, a transregulator of homeodomain proteins

The principal pathway for the metabolism of phenylalanine in mammals is via conversion to tyrosine in a tetrahydrobiopterin-dependent hydroxylation reaction occurring predominantly in the liver. Recently, the proposal that certain hyperphenylalaninemic children may have a deficiency of carbinolamine dehydratase, a component of the phenylalanine hydroxylation system, has widened the interest in this area of metabolism. Upon cloning and sequencing the dehydratase, we discovered that this protein is identical to DCoH, the cofactor which regulates the dimerization of hepatic nuclear factor 1 alpha, a homeodomain transcription factor. The identity of the nuclear and cytoplasmic proteins is demonstrated by size, immunoblotting, stimulation of phenylalanine hydroxylase, and dehydratase activity. The evolution of the dual functions of regulation of phenylalanine hydroxylation activity and transcription activation in a single polypeptide is unprecedented.

Vocal cord and pharyngeal weakness with autosomal dominant distal myopathy: clinical description and gene localization to 5q31

Distal myopathy refers to a heterogeneous group of disorders in which the initial manifestations are weakness and atrophy of the hands and feet. We report a family segregating an autosomal dominant distal myopathy, with multiple affected individuals in whom vocal cord and pharyngeal weakness may accompany the distal myopathy, without involvement of the ocular muscles. To our knowledge, this pedigree displays a distinct distal myopathy with the added features of pharyngeal and vocal cord dysfunction (VCPDM) that has not been previously reported. We mapped the MPD2 gene for VCPDM to chromosome 5q within a 12-cM linkage interval between markers D5S458 and D5S1972 in a large pedigree (a maximum LOD score of 12.94 at a recombination fraction of 0 for D5S393) and combined genome screening and DNA pooling successfully adapted to fluorescent markers. This technique provides for the possibility of fully automated genome scans.

Responses of bovine lymphocytes to heat shock as modified by breed and antioxidant status

We tested whether resistance of lymphocytes to heat stress is modified by breed, intracellular glutathione content, and extracellular antioxidants. In the first experiment, lymphocytes from Angus (Bos taurus, non-heat-tolerant), Brahman (B. indicus, heat-tolerant), and Senepol (B. taurus, heat-tolerant) heifers (12 heifers per breed) were cultured at 45 degrees C for 3 h to evaluate thermal killing, at 42 degrees C for 12 h in a 60-h phytohemagglutinin-induced proliferation test, and at 42 degrees C for 1 h to measure induction of heat shock protein 70 (HSP70). Killing at 45 degrees C was affected by breed x temperature (P < .01); the decrease in viability caused by a temperature of 45 degrees C was greater for Angus than for Brahman or Senepol. For phytohemagglutinin-stimulated lymphocytes, heating to 42 degrees C reduced [3H]thymidine incorporation equally for all breeds. Viability at the end of culture was affected (P < .001) by a breed x temperature interaction because the decrease in viability caused by culture at 42 degrees C was greatest for lymphocytes from Angus heifers. Heat shock for 1 h at 42 degrees C caused a two- to threefold increase in intracellular concentrations of HSP70, but there was no interaction of temperature with breed. In another experiment (with lymphocytes harvested from three Holstein cows), buthionine sulfoximine, a glutathione synthesis inhibitor, inhibited (P < .01) proliferation of phytohemagglutinin-stimulated lymphocytes at 38.5 and 42 degrees C. Addition of the antioxidants glutathione or thioredoxin to culture did not reduce the effects of heating to 42 degrees C on proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic hemangioendothelioma: clinical experience and management strategy

PURPOSE

This study sought to define management strategies based on clinical experience in treating infantile hepatic hemangioendothelioma.

METHODS

A retrospective analysis of patients with hemangioendothelioma presenting to a tertiary liver transplantation center between 1989 and 1997 was performed.

RESULTS

Thirteen patients (median age, 14 days) with hemangioendothelioma were identified. Congestive heart failure (P<.03) and abdominal mass (P<.081) were predictive of 5-month mortality rates. Ultrasonography and computerized axial tomography were the diagnostic modalities most commonly used. Treatment strategies consisted of medical management (steroids and alpha-interferon) and interventional modalities (hepatic artery ligation or embolization, resectional surgery, or orthotopic liver transplantation). Patients who underwent resectional surgery, with or without orthotopic liver transplantation, had a lower 5-month mortality rate (P<.02) and a greater 2-year survival rate (P<.003) than did those who underwent hepatic artery ligation or embolization. Early morbidity and mortality tended to be a consequence of the primary lesion, whereas late morbidity and mortality were reflective of the treatment modality used.

CONCLUSIONS

In cases of failed medical management, resectional therapy should be used when possible. If partial hepatectomy is not technically achievable, hepatic artery embolization should be used either as definitive therapy or as a temporizing measure until orthotopic liver transplantation is possible.

Sofosbuvir and simeprevir for treatment of hepatitis C virus infection in liver transplant recipients

Recurrent hepatitis C virus (HCV) infection occurs universally in the allograft in the absence of effective antiviral therapy before liver transplantation (LT). Antiviral therapy with sofosbuvir and simeprevir has proven to be highly effective and well tolerated in the nontransplant setting for treatment of HCV genotype 1 infection; therefore, we sought to evaluate the efficacy and safety of this regimen in LT recipients with recurrent HCV infection. This was a retrospective analysis of a single-center treatment protocol of patients with HCV genotype 1 infection who received a 12-week combination regimen of sofosbuvir and simeprevir. Sixty-one patients (35 with genotype 1a and 26 with genotype 1b) completed treatment with simeprevir and sofosbuvir. Three patients received additional ribavirin. Laboratory data and clinical assessments performed at the baseline, on treatment, at the end of treatment, and 12 weeks after the completion of antiviral therapy [sustained virological response at 12 weeks (SVR12)] were analyzed. The median time after LT was 5.4 years [interquartile range (IQR), 1.9-8.4 years], and tacrolimus was the most commonly used immunosuppressive agent (80.3%). Overall, SVR12 was achieved in 93.4% [95% confidence interval (CI), 84%-97%] of LT recipients treated with 12 weeks of sofosbuvir and simeprevir. When they were analyzed according to the HCV subtype, LT recipients with genotype 1b had a 100% SVR12 rate (95% CI, 87%-100%), whereas SVR12 was 89% (95% CI, 74%-95%) for those with genotype 1a. Advanced fibrosis (METAVIR F3-F4) was associated with diminished antiviral efficacy in LT recipients with genotype 1a [SVR12, 67% (95% CI, 39%-86%); P = 0.01]. Overall, the incidence of adverse events (AEs) was low, and no severe AEs occurred during treatment. In conclusion, treatment with a 12-week regimen of sofosbuvir and simeprevir was well tolerated and resulted in a high SVR12 rate for LT recipients with recurrent HCV genotype 1 infection. Genotype 1a patients with advanced fibrosis of the allograft were more likely to relapse.

gamma-Glutamyltransferase is a Helicobacter pylori virulence factor but is not essential for colonization

The contribution of glutamyl transpeptidase (GGT) (gamma-glutamyltransferase [EC 2. 3. 2. 2]) to Helicobacter pylori virulence was investigated in piglets and mice using GGT-deficient isogenic strains. All animals became colonized. However, the bacterial load was significantly lower for mutant bacteria than for parent strains. These results suggest that GGT activity provides an advantage to H. pylori in colonization.

In vivo correlation of tumor blood volume and permeability with histologic and molecular angiogenic markers in gliomas

BACKGROUND AND PURPOSE

Tumor angiogenesis is very heterogeneous and in vivo correlation of perfusion imaging parameters with angiogenic markers can help in better understanding the role of perfusion imaging as an imaging biomarker. The purpose of this study was to correlate PCT parameters such as CBV and PS with histologic and molecular angiogenic markers in gliomas.

MATERIALS AND METHODS

Thirty-six image-guided biopsy specimens in 23 patients with treatment-naive gliomas underwent PCT examinations. We correlated MVD, MVCP, VEGFR-2 expression, tumor cellularity, and WHO grade of the image-guided biopsy specimens with the PCT parameters. Histologic sections were stained with hematoxylin-eosin, CD34, and VEGFR-2 and examined under a light microscope. These histologic and molecular angiogenic markers were correlated with perfusion parameters of the region of interest corresponding to the biopsy specimen. Pearson correlation coefficients and multiple regression analyses by using clustering methods were performed to assess these correlations.

RESULTS

CBV showed a significant positive correlation with MVD (r = 0.596, P < .001), whereas PS showed a significant positive correlation with MVCP (r = 0.546, P = .001). Both CBV (r = 0.373, P = .031) and PS (r = 0.452, P = .039) also showed a significant correlation with WHO grade. VEGFR-2 positive specimens showed higher PS and CBV; however, neither was statistically significant at the .05 level.

CONCLUSIONS

CBV showed a significant positive correlation with MVD, whereas PS showed a significant positive correlation with MVCP, suggesting that these 2 perfusion parameters represent different aspects of tumor vessels; hence, in vivo evaluation of these could be important in a better understanding of tumor angiogenesis.