Effects of changes in calorie intake on intestinal nutrient uptake and transporter mRNA levels in aged mice

In aged, chronically calorie-restricted (CR) mice, intestinal nutrient uptake is significantly higher than in same-age ad libitum controls. Can this chronic restriction-induced enhancement of uptake be reversed by ad libitum feeding? We addressed this question by switching 32-mo-old chronically CR mice to ad libitum feeding for 4 wk (CRAL). Intestinal transport rate and total intestinal absorptive capacity for D-sugars and several nonessential L-amino acids decreased significantly in CRAL mice. In contrast, switching CR mice to an ad libitum regimen for only 3 d had no effect on intestinal nutrient transport, indicating that the negative effects of ad libitum feeding require a duration longer than the 3-d lifetime of most enterocytes. Permeability of the intestinal mucosa to L-glucose was independent of the switches in diet. Levels of the brushborder glucose transporter SGLT1, brushborder fructose transporter GLUT5, and basolateral sugar transporter GLUT2 mRNA as determined by reverse transcriptase-polymerase chain reaction in 6-, 24-, and 32-mo-old mice were each apparently independent of caloric restriction and age. We conclude that the high rates of intestinal nutrient uptake exhibited by chronically CR mice can be reversed by ad libitum feeding of only 1 mo duration. These decreases in uptake were due mainly to specific decreases in transport per unit weight of intestine and not to nonspecific decreases in intestinal mass. Changes in rates of sugar uptake induced by chronic CR and age are apparently not accompanied by changes in steady-state levels of mRNA coding for those transporters.

The identification and characterization of a G4-DNA resolvase activity

There is increasing evidence that four-stranded Hoogsteen-bonded DNA structures, G4-DNA, play an important role in cellular processes such as meiosis and recombination. The Hoogsteen-bonded G4-DNA is thermodynamically more stable than duplex DNA, and many guanine-rich genomic DNA sequences with the ability to form G4-DNA have been identified. A protein-dependent activity that resolves G4-DNA into single-stranded DNA has been identified in human placental tissue. The resolvase activity was purified from any apparent nuclease activity and is dependent on NTP hydrolysis and MgCl2. Resolvase activity is optimal with 5 mM MgCl2. The Vmax/Km of ATP is 0. 055%/min/microM, higher than the Vmax/Km of the other dNTPs. The products of the resolvase reaction are unmodified single-stranded DNA. The resolvase is not a duplex DNA helicase or a topoisomerase II activity and does not unwind Hoogsteen-bonded triplex DNA. Resolvase is a novel activity that unwinds stable G4-DNA structures using a dNTP-dependent mechanism producing unmodified single-stranded DNA. Potential in vivo roles for this G4-DNA resolvase activity are discussed.

[The residue and degradation of herbicide ammonium 2,4-dichloro-6-nitrophenate in the system of wheat and soil]

To study the residue and degradation of ammonium 2, 4-dichloro-6-nitrophenate (a herbicide) in wheat and soil, a field test was made in Wuxi Jiangsu of East China and Chengdu Sichuan of West Chain during 1985-1992. The results showed that ammonium 2,4-dichloro-6-nitrophenate was unstable with a half-life of 12-18 days in soil. The residue in wheat was less than 0.05 mg/kg on the field doses recommended. These results may be used as a basis for the hygienic evaluation of ammonium, 2,4-dichloro-6-nitrophenate.

[The relationship between pulmonary function and work ability of aging workers]

To explore the relationship between pulmonary function and work ability, a field study was conducted in 285 aging workers (aged 40 to 60) of different occupations in Chengdu area. The pulmonary function indices included FVC, FEV1, FEV1%, MMEF, and the pulmonary function index (PFI) which was the sum of the rating values from the first three indices. The work ability index (WAI) was also measured. Between work types, the indices, including FVC and FEV1%, showed significant difference (P < 0.05); FVC also showed significant difference between male and female workers (P < 0.05). There was a significant relationship between PFI (including FEV1% and MMEF) and WAI (P < 0.05), but the relationship between FVC (or FEV1) and WAI was not statistically significant (P > 0.05). Moreover, the agreement percentage between the classifications of PFI and WAI was 43.8%; the disagreement percentage was 4.56%. The results suggest that FEV1% and MMEF may be beneficial to the objective evaluation of the work ability of aging workers.

High prevalence of hantavirus infection in a group of Chinese patients with acute hepatitis of unknown aetiology

In southwestern China, small but substantial numbers of patients with acute hepatitis were found without known hepatropic viral infections (hepatitis A, B, C, D or E, cytomegalovirus, Epstein-Barr virus) and were receiving no hepatotoxic drugs. Prevalence of antibodies, both neutralizing and specific immunoglobulin (Ig)M and IgG, to Hantaan virus were evaluated in a cohort of 136 such patients: 83 were of unknown aetiology, 53 had known viral hepatitis and 59 healthy subjects acted as controls. The results showed that the incidence of neutralizing antibody to Hantaan virus in acute hepatitis patients with non-hepatitis A-E virus infections (13 of 83) was significantly higher than in those with A-E infections (0 of 53, P<0.01). Furthermore, the incidence of specific IgM antibody to Hantaan virus in acute hepatitis patients with non-hepatitis A-E virus infections (6 of 83) was significantly higher than in those with A-E infections (0 of 53, P<0.05) and in healthy subjects (0 of 59, P < 0.05). These findings suggest that Hantaan virus may be an important agent, contributing, at least in southwestern China, to a significant number of the cases of acute hepatitis of unknown aetiology. This hantavirus infection resulted in an acute hepatitis, differing from the typical diseases: haemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS).

Both the paired domain and homeodomain are required for in vivo function of Drosophila Paired

Drosophila paired, a homolog of mammalian Pax-3, is key to the coordinated regulation of segment-polarity genes during embryogenesis. The paired gene and its homologs are unusual in encoding proteins with two DNA-binding domains, a paired domain and a homeodomain. We are using an in vivo assay to dissect the functions of the domains of this type of molecule. In particular, we are interested in determining whether one or both DNA-binding activities are required for individual in vivo functions of Paired. We constructed point mutants in each domain designed to disrupt DNA binding and tested the mutants with ectopic expression assays in Drosophila embryos. Mutations in either domain abolished the normal regulation of the target genes engrailed, hedgehog, gooseberry and even-skipped, suggesting that these in vivo functions of Paired require DNA binding through both domains rather than either domain alone. However, when the two mutant proteins were placed in the same embryo, Paired function was restored, indicating that the two DNA-binding activities need not be present in the same molecule. Quantitation of this effect shows that the paired domain mutant has a dominant-negative effect consistent with the observations that Paired protein can bind DNA as a dimer.

Reduced hydrogen peroxide production in neutrophils from patients with diabetes

We evaluated the effects of granulocyte colony-stimulating factors (G-CSF), granulocyte-macrophage colony-stimulating factors (GM-CSF) and phorbol myristate acetate (PMA) on H2O2 production in purified neutrophils from patients with diabetes mellitus (DM), using flow cytometry. Twenty-two age-matched male subjects were selected: 11 were normal volunteers and the remainder had DM. No significant differences in intracellular H2O2 production per 60 min was observed in the "resting' neutrophils from DM patients (37.2 +/- 20.4 A.U.) compared with those from normal volunteers (24.9 +/- 8.4 A.U.). The PMA-stimulated neutrophils from normal volunteers generated approximately 4-fold increases in H2O2 per 60 min compared with those from DM patients. Under similar culture conditions, G-CSF caused 1.6-fold increases of H2O2 in neutrophils from normal volunteers compared with those of DM patients. Increases after GM-CSF stimulation were 2-fold higher in volunteer neutrophils compared with those from DM patients. The levels of G-CSF- or GM-CSF-stimulated H2O2 production in neutrophils from DM patients were low and were little different from non-stimulated resting cells. These data showed that H2O2 production in neutrophils induced by PMA is impaired in patients with DM, and neither G-CSF nor GM-CSF enhances its production.

[The evaluation of oscillatory potentials of the electroretinogram in the early diagnosis of the patients with primary open angle glaucoma]

PURPOSE

To study the changes in the oscillatory potentials (OPs) of the electroretinogram in the earlier or early stage of primary open angle glaucoma.

METHODS

OPs were recorded in thirty-three normal subjects (66 eyes) and 30 patients with primary open angle glaucoma (POAG) (58 eyes). The abnormal rates of OPs in the different stages of POAG were analyzed and the sensitivity and the specificity of OPs were also determined.

RESULTS

The overall OPs amplitudes (sigma o) were reduced in the patients with POAG and the amounts of small wavelets were also decreased. The total abnormal rate of sigma o was 67.24%, and 42.86% in the earlier stage, 65.38% in the early stage and 76.00% in the advanced and late stage. The sensitivity and the specificity of OPs were 67.24% and 92.42%. OPs had correlation with C/D.

CONCLUSION

OPs can be considered as an indicator of earlier or early diagnosis of patients with POAG before visual field loss is detected.

The changes of pattern reversal visual evoked potentials in normal infants

PURPOSE

To study pattern reversal visual evoked potential (PVEPs) and determine the developmental character and mature time of visual function in normal infants at different months of age.

METHODS

PVEPs were recorded from 115 normal infants at 3, 6, 9, 12 months age. P1 latency for different checks (1 degree 40', 25', 6') was analyzed and compared to those of normal adults. Changes of N1, N2 latency of PVEPs were also examined.

RESULTS

P1 latency for all checks (1 degree 40', 25', 6') was significantly longer at 3 months than at 6 months of age (P < 0.05), but no significant differences can be seen after 6 months of age for larger (1 degree 40') and intermediate (25') checks (P > 0.05). P1 latency for larger checks (1 degree 40') reached adult level after 3 months of age, but not for the intermediate check (25'), while P1 latency for small check (6') presented the character of fluctuation.

CONCLUSION

The visual system continued to develop after birth and appeared a certain regularity. Our results showed that P1 latency for larger check (1 degree 40') reached adult levels after 3 months of age. But P1 latency for intermediate check still has not reached adult levels after 3 months of age. To determine the age at which adult levels are finally reached, infants of 12 months and older must be tested. The reason why P1 latency for smaller check (6') presented the character of fluctuation should be the temporal tuning function developing much more slowly.

A study on national differences in identification standards for Chinese skull-image superimposition

This study selected 15 nationalities as test subjects among 56 nationalities in China, each having a population of > 1,000,000 million and characterized by significant features in physical type. The test nationalities include Yi, Bai, Dai, Yao, Korean, Hui, Man, Zhuang, Miao, Dong, Bouyei, Mongol, Zang, Uygur and Kazak nationalities. Three thousand test subjects (100 males and 100 females for each nationality) were randomly selected to be photographed, tested and observed by means of somatometry of faces, photographs of facial landmarks and X-ray photography. In accordance with this result, an identification standard for skull-image superimposition was established for different nationalities and sexes. On the basis of this, we then made a comparison of identification indices between Han and 15 nationalities as well as a T-value test on the significance of national differences. The result of this study shows that the test values of indices for 15 test nationalities are all different from those for Han nationality and the difference greatly reveals regionality. For example, Han in the Northeast of China is similar to Man and Korean nationalities in the Northeast, but much different from Zhuang, Miao, Dai and Dong nationalities in the Southwest. The main differences are in head length, head breadth, alae nasi, nasal tip, mouth and zygoma, etc.

Evidence for a (triosephosphate isomerase-like) "catalytic loop" near the active site of glyoxalase I

The conformational mobility of glyoxalase I (Glx I) during catalysis has been probed using stable analogs of the enediol intermediate that forms along the reaction pathway: GSC(O)N(OH)R, where GS = glutathionyl and R = CH3 (1), C6H5 (2), C6H4Cl (3), or C6H4Br (4). For human erythrocyte Glx I, catalysis is unlikely to be coupled to major changes in protein secondary structure, as the circular dichroism spectrum of the enzyme (190-260 nm) is insensitive to saturating concentrations of either enediol analog or S-D-lactoylglutathione, the product of the Glx I reaction. However, a small conformational change is indicated by the fact that binding of enediol analog to the active site decreases intrinsic protein fluorescence by 11%, and protects the enzyme from proteolytic cleavage by Pronase E at the C-side of Ala-92 and Leu-93. In contrast, binding of S-D-lactoylglutathione does not affect protein fluorescence, and increases the rate of proteolytic cleavage by 1.5-fold. These observations are consistent with a model of catalysis in which a flexible peptide loop folds over and stabilizes the enediol intermediate bound to the active site. Indeed, a highly conserved sequence of amino acid residues is found near the proteolytic cleavage sites, for human Glx I (100-111) and Pseudomonas putida Glx I (93-105), that shows significant sequence homology to the "catalytic loop" of chicken muscle triosephosphate isomerase (TIM) (165-176). The active site base (Glu-165) of TIM, which catalyzes the proton transfer reaction during isomerization, corresponds in position to Glu-93 of P. putida Glx I. Consistent with a functional role for Glu-93, a mutant enzyme in which Glu-93 is replaced by Asp shows no detectable catalytic activity.

Vertical transmission of human immunodeficiency virus type 1: autologous neutralizing antibody, virus load, and virus phenotype

OBJECTIVE

To evaluate immunologic and virologic correlates of vertical transmission of human immunodeficiency virus type 1 (HIV-1).

DESIGN

Case-control study.

PATIENTS

Women who were prospectively enrolled in a natural history study of HIV-1 infection in women and infants. Sixteen HIV-1-infected women whose infants became infected were matched by CD4+ cell percentage and use of zidovudine during pregnancy with women whose infants did not become infected.

MEASUREMENTS

Maternal autologous neutralizing antibody, virus load determined by RNA-polymerase chain reaction (RNA-PCR), and virus phenotype.

RESULTS

Most women in both groups had low titers of autologous neutralizing antibody, and no difference in neutralizing titers was observed (range, < 4 to 181 in both groups). The HIV-1 copy number in maternal plasma was not significantly different in the two groups but was inversely correlated with maternal CD4+ cell percentage (p < 0.005). Five women in the transmitting group and four in the non-transmitting group had syncytium-inducing (SI) phenotype virus. Two infected infants had SI phenotype virus. The SI phenotype virus was associated with a greater HIV-1 copy number in maternal plasma (p < 0.05) and an increase in the mortality rate for the infants (p < 0.01).

CONCLUSIONS

In women matched for CD4+ cell percentage, low titers of autologous neutralizing antibody, high virus load, and SI phenotype virus were not associated with an increased risk of transmission of HIV-1 to their infants.

A rapid, direct test for zidovudine susceptibility in clinical isolates of human immunodeficiency virus type 1 (HIV-1) from infected children

BACKGROUND

Existing phenotypic tests of antiretroviral susceptibility in clinical isolates of human immunodeficiency virus (HIV) are expensive and slow, and require passage of virus in cell culture with the possible consequence of selecting variants.

OBJECTIVES

We sought to develop a rapid 14-day assay for zidovudine susceptibility of cell-associated HIV performed directly in patient blood samples.

STUDY DESIGN

Twenty-three tests were performed prospectively in 21 children, and the results were compared with those of the AIDS Clinical Trials Group/Department of Defense consensus drug susceptibility assay (DSA) as well as certain clinical parameters.

RESULTS

Five strains from ZDV-naive children were sensitive by the rapid test. Three were tested by DSA, and all were sensitive. Six strains from children who had received >/=24 months of ZDV were resistant by the rapid assay. Four of these strains were tested by the DSA, and all were shown resistant. The viral strains from children who received <24 months of therapy or who had switched from ZDV to other antiviral therapy exhibited variable sensitivity by both tests. Changes in CD4 cells in the subsequent 6 months, as well as weight gain during this time were both correlated to the results of the rapid test. The syncytium-inducing capacity of the virus strains was analyzed similarly.

CONCLUSIONS

The rapid intracellular virus susceptibility assay is a test of drug sensitivity performed on HIV growing in cells obtained directly from an infected patient. The test has a two-week turn-around time and, in this preliminary report, gives results which correlate with both time on zidovudine and also subsequent CD4 cell changes.

Dissection of the Drosophila paired protein: functional requirements for conserved motifs

The Drosophila paired gene encodes three conserved motifs: a homeodomain, paired domain and PRD (his/pro) repeat. To investigate the functional importance of the PRD repeat and paired domain, we tested deletion mutants using an ectopic expression assay in embryos. Our results suggest that the PRD repeat is not required for the in vivo regulation of the target genes, engrailed and gooseberry. However, the PRD repeat appears to be embedded within a proline-rich transcriptional activation domain required for the regulation of these genes. Our analysis of the paired domain indicated that its N-terminal half, which is required for DNA binding in vitro, is also required for in vivo function, whereas surprisingly, the C-terminal half is dispensable for the regulation of engrailed and gooseberry.

S-(N-aryl-N-hydroxycarbamoyl)glutathione derivatives are tight-binding inhibitors of glyoxalase I and slow substrates for glyoxalase II

S-(N-Aryl-N-hydroxycarbamoyl)glutathione derivatives are powerful competitive inhibitors of the anticancer target enzyme glyoxalase I. Indeed, the N-p-bromophenyl derivative is the strongest inhibitor of the enzyme from human erythrocytes yet reported (Ki = 1.4 x 10(-8) M). Structure-activity correlations indicate that the high affinities of the derivatives for both human and yeast glyoxalase I are due to the fact that the derivatives are hydrophobic analogs of the enediol(ate) intermediate associated with the glyoxalase I reaction. The derivatives also proved to be slow substrates for the thioester hydrolase glyoxalase II (bovine liver). Compounds of this type are of interest as potential tumor-selective anticancer agents, based on the abnormally low levels of glyoxalase II activity in some types of cancer cells.

Synergistic activation of transcription is mediated by the N-terminal domain of Drosophila fushi tarazu homeoprotein and can occur without DNA binding by the protein

Synergistic activation of transcription by Drosophila segmentation genes in tissue culture cells provides a model with which to study combinatorial regulation. We examined the synergistic activation of an engrailed-derived promoter by the pair-rule proteins paired (PRD) and fushi tarazu (FTZ). Synergistic activation by PRD requires regions of the homeodomain or adjacent sequences, and that by FTZ requires the first 171 residues. Surprisingly, deletion of the FTZ homeodomain does not reduce the capacity of the protein for synergistic activation, although this mutation abolishes any detectable DNA-binding activity. This finding suggests that FTZ can function through protein-protein interactions with PRD or other components of the homeoprotein transcription complex, adding a new layer of mechanisms that could underlie the functional specificities and combinatorial regulation of homeoproteins.

A cohort study in southern China of tin miners exposed to radon and radon decay products

Several studies of underground miners have demonstrated that exposure to radioactive radon gas (more precisely, 222Rn and its short-lived decay products) at levels historically found in mines increases the risk of lung cancer. Because of small numbers of lung cancers, previous studies have had limited power to evaluate temporal and other characteristics of patterns of risk. Herein we report on a historical cohort study of male employees of the Yunnan Tin Corporation in southern China. The cohort consists of 17,143 workers with 175,143 person-years of observation and 981 lung cancer events. Eighty percent of the workers were employed underground and exposed to radon. The excess relative risk increased linearly with exposure, rising 0.6% per working level month (95% confidence interval = 0.4-0.8). In the mines, workers were also exposed to arsenic-containing dusts. Adjustment for arsenic exposure, a known lung carcinogen, reduced the effect of radon exposure to 0.2% per working level month (95% confidence interval = 0.1-0.2). The excess relative risk/working level month declined significantly with attained age and with radon exposure rate as measured by the cumulative working level month divided by duration of exposure. It also declined significantly with years from last exposure and with time since exposure, but these declines were consistent only after adjustment for arsenic exposure. In this cohort, 41% of the underground workers were first exposed when < 15 y old; however, lung cancer risk did not vary consistently with age at first radon exposure. A joint analysis of radon exposure and smoking status (smoker vs. nonsmoker) rejected both an additive and a multiplicative association; the relationship was consistent with an intermediate association.

Development and Current Status of Skull-Image Superimposition - Methodology and Instrumentation

This article presents a review of the literature and an evaluation on the development and application of skull-image superimposition technology - both instrumentation and methodology - contributed by a number of scholars since 1935. Along with a comparison of the methodologies involved in the two superimposition techniques - photographic and video - the author characterized the techniques in action and the recent advances in computer image superimposition processing technology. The major disadvantage of conventional approaches is its relying on subjective interpretation. Through painstaking comparison and analysis, computer image processing technology can make more conclusive identifications by direct testing and evaluating the various programmed indices.

Light-dependent changes in ribulose bisphosphate carboxylase activase activity in leaves

An assay for the activity of ribulose bisphosphate carboxylase (Rubisco) activase in crude leaf extracts was developed. The assay is based on a spectrophotometric assay of Rubisco, and activase activity (in nanomoles activated Rubisco per minute per milligram chlorophyll) was calculated from the rate of increase in Rubisco activity over time. Activase activity measurements were made using samples from spinach (Spinacia oleracea) leaves undergoing (a) steady-state photosynthesis at various photon flux density (PFD) values and (b) nonsteady-state photosynthesis following an increase from darkness to a high PFD. Analysis of these samples showed that steady-state Rubisco activase activity was relatively low in darkness, increased with PFD, and saturated below 300 micromoles per square meter per second. Rubisco activity (measured spectrophotometrically) was also found to be low in darkness and to increase with PFD, but it saturated at much higher PFD values (approximately 1000 micromoles per square meter per second) along with the rate of photosynthesis. Following an increase in PFD from darkness to 650 micromoles per square meter per second, activase activity increased more or less linearly over a period of 5 to 6 minutes, after which it was constant. Rubisco activity, however, increased more slowly. The light-dependence of Rubisco activase is consistent with previous gas-exchange data showing two interdependent processes in the activation of Rubisco following an increase in PFD.

Determination of Apparent K(m) Values for Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase (Rubisco) Activase Using the Spectrophotometric Assay of Rubisco Activity

The spectrophotometric assay for ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) was used to determine the rate of increase in Rubisco activity over time in the presence or absence of Rubisco activase. Polynomial approximations to the raw data were used to smooth out minor fluctuations in the spectrophotometer readings, and Rubisco activase activity was expressed as nanomoles of activated Rubisco per minute. This assay was used to examine the effects of CO(2) and the inactive-Rubisco:ribulose 1,5-bisphosphate complex (ER) on the activase-catalyzed activation reaction. Double-reciprocal plots of activase activity and ER at several concentrations of CO(2) were consistent with two-substrate Michaelis-Menton kinetics, and the apparent K(m) (CO(2)) and K(m)(ER) were determined to be 53 and 2.7 micromolar, respectively. These data do not prove that ER and CO(2) are substrates for the reaction catalyzed by activase, but they may be important to our understanding of the activation process in vivo. The implications of these data and their relation to previously published data on the effects of ER and CO(2) on activase are discussed.

[A population-based study on types of viral hepatitis]

The epidemiological features of various types of acute viral hepatitis in 5 regions of Sichuan Province (211,639) population) form Feb.16, 1987 to Feb 15, 1988 were studied. One-year surveillance was carried out and the results showed an incidence rate of 167.74 per 100,000 for acute viral hepatitis. The proportional distribution of HA,HB,non-A,non-B Hepatitis (HNANB), Hepatitis with EBV (HEB), Hepatitis with CMV (HCM) and Mixed infection in all the patients being 24.51%, 38.31%, 24.51%, 3.38%, 3.38% and 5.92%, respectively. There was a proportion of 14.93% for superinfection. The incidence differences in these regions ranged from 110.30 per 100,000 to 299.95 per 100,000. The incidence of hepatitis peaked in spring, and the sex ratio (male:female) for acute viral hepatitis was 1.75:1 (P less than 0.001). There was a peak of attack rate for HA in 0-19 age group. The incidence of HB in 20-39 age group was obviously higher than that in other age groups. For HNANB, a relatively high attack rate was noticed in 5-19 age group, but no significant age-differences were noted for HEB,HCM and Mixed. Of 355 patients with acute viral hepatitis, 43.94% had a history of contact, and 36.62% a history of injection.