Increase of 5''-nucleotidase activity in liver plasma membranes during fasting in the rat

To better understand the common association of Giardia lamblia infection and allergic reactivity, total and specific IgE values were evaluated and different manifestations of symptomatic and asymptomatic infected human hosts were analyzed. The humoral, cellular, and nonspecific immune responses were evaluated in Cuban adults. Increased total serum IgE levels were significantly higher (p < 0.01) in Giardia patients than in negative controls; cure of giardiasis was characterized by a decrease in IgE levels and some patients regained normal IgE values. The skin test was positive in 91% (103/123) of chronic patients and only in 23% (20/123) of negative controls (p < 0.05). A positive test was seen in patients with antecedents of recent giardiasis (< 4 months). Specific IgE was higher in patients than in control sera, and in the former it decreased with sera dilution. During the follow-up period of cured patients, the proportion of IgE decreased and the opposite occurred in noncured patients. The cellular response evaluated by LIF was positive in 92% (11/12) of carriers and significantly higher (p < 0.05) than in symptomatic patients 8% (1/12); the same occurred with IgG and IgA antibody response; titers mainly of IgA were higher in asymptomatic carriers than in patients; all carriers were negative to the skin test. These results indicate the presence of total and specific IgE responses in humans infected with Giardia, but the response in symptomatic cases (patients) is different from that in asymptomatic cases (carriers).(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficient operation of a solid-state adaptive laser oscillator

We present the results of a cw diode-pumped Nd:YVO4 laser oscillator based on a self-starting adaptive gain-grating resonator. Adaptive laser operation has been demonstrated with 12-W output for 37 W of diode pumping, producing a TEM00 mode that compensates for thermal aberrations. The issue of the finite aperture of the amplifier is discussed, and a design that incorporates an intracavity lens is used to improve the collection efficiency with severe thermal lensing at high pump powers. The powers of the beams involved in the resonator are compared with theory and are found to be in good agreement. Spectral and temporal behavior of the adaptive laser is investigated, and very interesting behavior is shown, including self-induced temporal modulation dynamics and a switching between a narrowband and a broad bandwidth of operation.     

Genetic locus heterogeneity in Lafora's progressive myoclonus epilepsy

In 1995, we mapped a gene for Lafora's progressive myoclonus epilepsy in chromosome 6q23-25. In 1997 and 1998, we reduced the size of the locus to 300 kb, and an international collaboration identified mutations in the protein tyrosine phosphatase gene. Here, we examine for heterogeneity through the admixture test in 22 families and estimate the proportion of linked families to be 75 to 85%. Extremely low posterior probabilities of linkage (Wi), exclusionary LOD scores, and haplotypes identify 4 families unlikely to be linked to chromosome 6q24.     

Disposable contact lens use as a risk factor for microbial keratitis

AIMS: A case-control study was performed to evaluate soft contact lens (SCL) wear modality as a risk factor for microbial keratitis. METHODS: Contact lens wearers presenting as new patients to Moorfields Eye Hospital accident and emergency department during a 12 month period completed a self administered questionnaire detailing demographic data and contact lens use habits. Cases were patients with a clinical diagnosis of SCL related microbial keratitis. Controls were SCL users attending with disorders unrelated to contact lens wear. Odds ratios (estimates of relative risks) and 95% confidence limits (CL) were calculated through multivariable logistic regression analysis. RESULTS: There were 89 cases and 566 controls. A substantially increased risk with 1-4 weekly disposable SCL compared with non-disposable SCL was identified among both daily wear (DW) (odds ratio = 3.51, 95% CL 1.60-7.66, p = 0.002) and extended wear (odds ratio 4.76, 95% CL 1.52-14.87, p = 0.007) users after adjustment for demographic, lens use and hygiene variables. Other significant factors among DW users were "occasional" overnight use, use of chlorine based (as opposed to other chemical) systems in combination with poor storage case hygiene, and irregular disinfection. CONCLUSION: Properties of some disposable SCL may be partly responsible for these excess risks. It is also possible, however, that this finding is largely a reflection of widespread complacency among patients and practitioners with respect to disposable SCL fitting and use.     

In vitro activity of a new oral triazole, BMS-207147 (ER-30346)

One viral strand of phi Lf, a filamentous phage of Xanthomonas campestris pv.campestris, the open reading frame (ORF440) behind gene VI was identified as gene I. This gene codes for pI protein (440 aa, 48 kDa) which was shown to be membrane-bound in the phi Lf-infected host cell by Western blot analysis using the antibody raised against the protein expressed in Escherichia coli. Its predicted amino acid sequence has a nucleotide-binding motif in the N-terminal 97 aa and a membrane-spanning domain (aa 221 to 236). These structural features are characteristic of pIs of several filamentous phages which are transmembrane proteins required for phage assembly. Thus far, nine phi Lf genes have been identified which are organized in the order GII-gX-gV-gVII-gIX-gVIII-gIII-gVI-gI, similar to the genome organization of E. coli filamentous phages.     

Paints and coatings monitored by laser-induced breakdown spectroscopy

Two algorithms—peak picking and peaks correlation—have been compiled in a portable laser-induced breakdown spectroscopy (LIBS) system and used specifically for spectral fingerprinting of paints and coatings, which contain multiple ingredients and require several application steps. The LIBS technique starts with a laser shot on the specimen surface, detection of the emission of the elements present, and analysis of the sample compositions. The LIBS system has been successfully illustrated for the identification and analysis of coating substrates, surface pretreatments, and primer and topcoat paints obtained in the lab and at field sites. The results indicate that, despite the compositional complexity in organic metal finishing, the spectral fingerprint of paints and coatings can be effectively determined by the LIBS technique. The advantages of LIBS technique over other conventional methods, such as EDX, are that it is quasi-nondestructive (<100 μm of sample size), requires no sample preparation, is fast (within minutes), is user-friendly (for nontechnical personnel), and is capable of application both online and at the field sites.     

Effect of sodium azide on the ultrastructural preservation of tissues.

An electron microscopic study was carried out to examine the quality of ultrastructural preservation of parenchymatous and mesenchymatous tissues and isolated cells fixed in glutaraldehyde with sodium azide (NaN3) as an additive. The dense tissues fixed with conventional glutaraldehyde containing calcium chloride demonstrated only a narrow zone of good tissue preservation on the surface of the specimens. Addition of azide at a concentration of 0.1% greatly improved the cellular preservation in the deeper region of tissues, in particular with respect to the mitochondrial morphology. There was no adverse effect on other cell organelles. The improvement in mitochondrial preservation and the enhancement of penetration of the fixative is presumably due to selective and instantaneous inhibition of mitochondrial metabolic activity by the azide, thus retarding anoxic degenerative effects on cellular structures until permanent fixation is completed by the comparatively slow-acting aldehyde. However, the addition of azide offers no significant improvement in the ultrastructural preservation of isolated lymphocytes and liver cells, or fibroblasts maintained in culture.     

Liver glucose-6 phosphatase activity is inhibited by refeeding in rats

This study was conducted to determine whether inhibition of hepatic glucose-6 phosphatase is involved in the mechanism of suppression of hepatic glucose production during the postprandial period. We studied the time course of changes in the enzyme activity by refeeding food-deprived rats with nonpurified diet. The Vmax of the enzyme, assayed in homogenates from livers freeze-clamped in situ in anesthetized 48-h unfed rats (12.3 +/- 0.15 U/g wet liver, mean +/- SEM, n = 6) was progressively decreased upon refeeding: 11.1 +/- 0.5, 8.5 +/- 0.4 and 7.9 +/- 0.5 U/g, in rats refed for 90, 180 (P < 0.01) and 360 min (P < 0.01), respectively. The Km of the enzyme was not affected by refeeding. No inhibition of the enzyme was observed in microsomes purified from these homogenates, suggesting a metabolite-induced inhibition mechanism. To assess the role of insulin in the inhibition, we assayed the glucose-6 phosphatase activity in similarly processed liver homogenates from food-deprived rats perfused with insulin at physiological and supraphysiological concentrations, whereas plasma glucose was maintained at the basal level by adapted glucose perfusion (euglycemic clamps). No inhibition of glucose-6 phosphatase was found under these conditions, suggesting that insulin cannot by itself account for the inhibition observed in the refeeding experiments. These data constitute the first demonstration of the inhibition of glucose-6 phosphatase activity during the postprandial period.