Biochemical and morphological changes in the lenses of selenium and/or vitamin E deficient rats

The activities of glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), superoxide dismutase (SOD) and the contents of malondialdehyde (MDA) and free radicals were measured, and the morphological changes were observed in the lens of control rats, selenium-deficient (SeD) and/or vitamin E deficient (VED) rats. The activities of GSH-Px in the lens of SeD rats decreased significantly. The GSH-Px activities of lens were positively related to erythrocytes selenium level. There was a free radical at g = 2.0015 in the rat lens of all groups, but the content of free radicals in the lens of SeD group was significantly higher than that of the control group. The free radical content of lens was negatively related to erythrocytes selenium level, as well as the GSH-Px activities in the lens. In vitro, ultraviolet radiation caused the generation of another kind of free radical (g = 2.0097) in the lens of all groups, but the amount of the free radical in the lens of the SeD group was also significantly higher than that of the control group. The activities of SOD and GSSG-R in VED rat lens were significantly decreased. The amount of MDA in the lens of SeD and/or VED rats were significantly increased. The results showed that the decrease of antioxidative capability in the lenses of SeD and/or VED rats accelerated the lipid peroxidation and generation of free radicals. Although only early morphological changes in SeD and/or VED rat lens were observed, it is considered that selenium and vitamin E deficiency may be involved in the occurrence of cataract.

Molecular cloning and sequencing of the mucin subunit of a heterodimeric, bifunctional cell surface glycoprotein complex of ascites rat mammary adenocarcinoma cells

Ascites sublines of the highly metastatic 13762 rat mammary adenocarcinoma contain abundant amounts of a heterodimeric cell surface glycoprotein complex composed of a mucin subunit ASGP-1 (ascites sialoglycoprotein-1) and a transmembrane subunit (ASGP-2). Previous studies showed that the complex is synthesized from a single polypeptide encoded by a 9 kb transcript. The sequence of the transmembrane subunit was obtained from a 5-kilobase (kb) cDNA isolated from a plasmid library (Sheng, Z., Wu, K., Carraway, K. L., and Fregien, N. (1992) J. Biol. Chem. 267, 16341-16346). Completion of the sequence of this cDNA revealed the C-terminal domain of ASGP-1, which is rich in serine and threonine but contains no typical mucin-type repeats. The remainder of the sequence of ASGP-1 and the 9-kb transcript was obtained by two 5'-RACE (rapid amplification of cDNA ends) steps and primer extension analysis. These results revealed that the 5' half of the 9-kb transcript contains a short 5'-noncoding region and encodes a signal sequence, a short nonrepeat region, and a repeat domain containing 11 repeats. Nine of these repeats are found in tandem, but the two end repeats are separated from the others by short unique sequences. The repeats vary from 117-124 amino acids and are 70-90% identical to a consensus sequence. Overall, the sequence predicts that ASGP-1 contains 2172 amino acids (M(r) 224,190), 43% of which are serine and threonine. We propose that the complex of this mucin and its transmembrane subunit, which contains growth factor-modulating activity, may play an important role in tumor progression.

Overexpression of p53 and HER-2/neu proteins as prognostic markers in early stage breast cancer

OBJECTIVE

Overexpression of the p53 and HER-2/neu oncogenes are the two most common genetic abnormalities associated with breast cancer. Shorter survival time has been reported in patients with tumors with p53 or HER-2/neu. This report analyzes a retrospective cohort of early stage breast cancers for both oncogenes and relates overexpression to clinicopathologic parameters and survival.

METHODS

Immunostaining for p53 and HER-2/neu was performed on 230 paraffin-embedded specimens of stage I and II breast cancers diagnosed and treated at Duke University Medical Center between 1984 and 1987. Positive staining for both p53 and HER-2/neu in paraffin-embedded tissues indicates an underlying genetic abnormality: point mutations in the p53 gene and amplification of the HER-2/neu gene.

RESULTS

In this cohort of patients, 24% were positive for p53 and 17% for HER-2/neu. Four per cent were positive for both oncogenes. Significant correlations were found between p53 immunostaining and increasing tumor size, stage, and low estrogen and progesterone receptor contents. Univariate analysis showed that p53 and HER-2/neu were indicators of overall and failure-free survival. An additive effect on survival was observed in patients with both oncogene abnormalities. Nodal status, HER-2/neu, and p53 all attained independent prognostic value in a multivariate analysis.

CONCLUSIONS

The p53 and HER-2/neu oncogenes have proven but limited prognostic value. An approach that combines several molecular genetic markers with established pathologic criteria may help physicians to make more accurate predictions of prognosis in patients with early stage breast cancer.

[The prognostic characteristics of hypertensive left ventricular hypertrophy in a rural population]

One hundred and twenty-six rural hypertensive patients with ECG left ventricular hypertrophy (HT-LVH) were followed up for 10 years to investigate the prognostic characteristics in a population with low prevalence of hypertension (2.93%) and low plasma cholesterol (4.59 +/- 1.00mmol/L). A cohort of age, sex, region and occupation matched hypertensives without LVH (HT, n = 163) and normotensives (NT, n = 275) served as controls. The major cause of death in rural hypertensives with ECG LVH in this study was stroke (56.8%). After stratification of BP, no significant difference of stroke risk was found between patients with LVH and hypertensives without LVH, while cardiovascular risk in the patients with LVH plus ST segment depression persisted. LVH per se seems not to be an independent factor for stroke. The high stroke rate in patients with LVH may be ascribed to the coexisting higher level of BP. After adjustment of coexisting hypertension, ECG LVH based on voltage only was not an independent risk factor of stroke and cardiovascular events, while LVH plus ST segment depression was closely related to cardiovascular events. In this low level, plasma cholesterol did not affect the mortality rate of stroke.

Variation in breast cancer surgery in Ontario

OBJECTIVES

To analyse the extent of variation by county and hospital in the use of breast-conserving surgery in the initial management of breast cancer and to assess some factors that might explain the observed variation.

DESIGN

Population-based retrospective cohort study.

SETTING

Ontario.

PATIENTS

All women with breast cancer newly diagnosed from Jan. 1, 1989, to Dec. 31, 1991.

MAIN OUTCOME MEASURE

Proportion of women undergoing unilateral breast cancer surgery who had breast-conserving surgery in each hospital and county.

RESULTS

Of the 14,570 women with newly diagnosed breast cancer 12,815 (88.0%) underwent unilateral breast cancer surgery. The mean proportion of breast-conserving procedures by county was 52% and ranged from 11% to 84%. The proportion of breast-conserving procedures in individual hospitals with one or more cases of breast cancer per month ranged from 6% to 84%. The variations in the rates between hospitals was greater than that expected by chance alone (p < 0.0001).

CONCLUSIONS

There was marked variation at the hospital and county level in the use of breast-conserving surgery in the initial management of breast cancer. This variation was strongly associated with the hospital where the surgery was performed.

Folate Metabolism in Datura innoxia (In Vivo and in Vitro Folylpolyglutamate Synthesis in Wild-Type and Methotrexate-Resistant Cells)

In vivo folylpolyglutamate pools of the wild-type (Px4) and methotrexate-resistant (MTX161) Datura innoxia cell lines were detected by incorporation of [14C]p-aminobenzoate into folates. The folylpolyglutamate derivatives were cleaved to p-aminobenzoylpolyglutamates and separated according to glutamyl chain length by high-performance liquid chromatography. Hexaglutamates were the predominant form in both Datura cell lines. The proportions of individual folylpolyglutamates were unaffected by culturing the cells in medium containing products of one-carbon metabolism such as glycine, adenine, thymidine, or methionine. Radiolabeling of the hexaglutamates was greatly reduced in the presence of 10-8 M methotrexate (MTX) in the Px4 cells but not in the MTX161 cells. Tetrahydrofolate, 5, 10-methylenetetrahydrofolate, and folinic acid were effective substrates for the folylpolyglutamate synthetase from Datura cells in vitro, whereas MTX and folate were poor substrates. In vivo, MTX can be slowly converted into its polyglutamate derivatives up to MTXGlu4 or MTXGlu5 in Datura cells in the longer term. Significantly lower levels of MTX polyglutamates in MTX161 cells were found compared with those of Px4 cells during prolonged (10 d) exposure to MTX. Although in vivo and in vitro folylpolyglutamate synthesis was found to be similar in both cell lines, about a 4-fold increase in specific activity of [gamma]-glutamyl hydrolase (GGH) was detected in the MTX161 cell line. The increase in GGH in the resistant cells suggested that breakdown of polyglutamylated forms of MTX may play a role in acquired MTX resistance.

[Relations between opacification of lens protein and pH]

Some of the acidic reagents or medicines (i.e. HCl, GSH & GSSG, Vit. C, Vit. B6) and basic reagents (Tris) were used to regulate the pH of water soluble protein and urea soluble protein solution of human lenses. At a certain pH, the lens protein solution appears opalescence, the pH of opacity solution which is measured by pH meter is around 5.6-6.3. The opalescence of water soluble and urea soluble lens protein solution of human fetal, adult and cataractous lenses were also determined by gradient acidic and basic solution. The result show that the opacity is more obvious in soluble protein solution of cataractous lenses and clear lenses than in that of fetal lenses, and the lens urea soluble protein has a marked opalescence in comparison with the water soluble protein. So we assume that cataractogenesis might be associated with the change of pH within lens.

The prognostic characteristics of hypertensive left ventricular hypertrophy in a population with low prevalence of hypertension and low plasma cholesterol

One hundred and twenty-six hypertensive patients with ECG left ventricular hypertrophy (HT-LVH) were followed for 10 years to investigate the prognostic characteristics in a population with low prevalence of hypertension (2.93%) and low plasma cholesterol (4.26 +/- 0.91 mmol/L). A cohort of age-, sex-, region- and occupation-matched, randomized hypertensives without ECG-LVH (n = 163) and normotensives (n = 275) served as controls. HT-LVH was found to be associated with an increased risk of overall death, stroke mortality and cardiovascular mortality. The major cause of death in rural hypertensives with ECG-LVH was stroke (56.8%). After adjusting BP and BP stratification, no significant difference of stroke risk was found between patients with and without LVH, while cardiovascular risk persisted in patients with LVH plus ST segment depression. LVH per se did not appear to be an independent factor for stroke death. Higher stroke mortality in patients with LVH may be ascribed to the coexisting higher level of BP. Furthermore, after adjusting for the coexisting hypertension, ECG-LVH in terms of voltage only was not related to the prognosis of stroke and cardiovascular death. The mortality rate of stroke was not affected by plasma cholesterol levels, as the levels seen were in a low range.

Virus DNA detection of herpes simplex keratitis by PCR

HSV-DNA of seven corneal lesions suspected with herpes simplex keratitis (HSK) and nine normal human donor corneas were detected by PCR. Five out of seven diseased corneas showed positive results, and the other two diseased corneas and nine normal corneas negative. The results suggest the PCR may be useful as a rapid and sensitive method for diagnosing HSK.

Protein product of the somatic-type transcript of the Hoxa-4 (Hox-1.4) gene binds to homeobox consensus binding sites in its promoter and intron

The murine Hoxa-4 gene encodes a protein with a homeodomain closely related to those produced by the Antennapedia-like class of Drosophila genes. Drosophila homeodomain proteins can function as transcription factors, binding to several specific DNA sequences. One sequence that is frequently encountered contains a core ATTA motif within a larger consensus sequence, such as CAATTAA. The in vitro synthesized protein product of Hoxa-4 was shown to bind to a subset of restriction fragments of the Hoxa-4 gene itself as determined by gel retardation experiments. Direct examination of the sequences of the fragments bound by Hoxa-4 protein revealed the presence of four regions containing the core ATTA motif. Two regions contained sequences of the CAATTAA class and were located approximately 1 kb upstream from the putative somatic Hoxa-4 promoter and within the intron. Two additional binding sites containing the consensus target sequence involved in autoregulation of Drosophila Deformed gene were identified: one immediately downstream of the putative embryonic transcription start site and one within the intron, respectively. Specific binding of the in vitro produced Hoxa-4 protein to oligonucleotides corresponding to these sequences was observed in gel retardation assays. The same results were obtained with Hoxa-4 protein produced in a Baculovirus expression system. Experiments using oligonucleotides containing base substitutions in positions 1, 3, 4, and 5 in the sequence CAATTAA showed severely reduced binding. The use of truncated mutant Hoxa-4 proteins in gel retardation assays and in transient co-transfection experiments revealed that the intact homeodomain was required for the binding. These results also suggested that the Hoxa-4 gene has the potential to auto-regulate its expression by interacting with the homeodomain binding sites present in the promoter as well as in the intron.

Anti-HIV-1 activity and cellular pharmacology of various analogs of gossypol

We previously reported that the racemic mixture and both enantiomers of gossypol inhibit the replication of human immunodeficiency virus-type 1 (HIV-1) (Lin et al., Antimicrob Agents Chemother 33: 2149-2151, 1989). The present study evaluates the activities of a variety of analogs of gossypol as well as a few non-gossypol analogs. Compounds 2, 3, 10, and 13 were slightly more inhibitory than (-)-gossypol to the replication of HIV-1 in cell culture. Compounds 4 and 8 were cytotoxic to human peripheral blood monocyte (PBM) cells, and compounds 2 and 3 were cytotoxic to Vero cells but not PBM cells. The effects of the two enantiomers of gossypol on the cell volume and migration of H9 cells through the cell cycle were evaluated during 72 hr of incubation. The (-)-enantiomer of gossypol was more toxic to H9 cells than the (+)-enantiomer of gossypol as evidenced by cell destruction. Prior to cell destruction, there appeared to be no significant effect on cell cycle distribution with either enantiomer.

Randomized trial of high-dose chemotherapy with autologous bone marrow support as adjuvant therapy for high-risk, multi-node-positive malignant melanoma

BACKGROUND

Chemotherapy adjuvant to surgery in metastatic melanoma has been evaluated in only a few prospective randomized trials. In the treatment of metastatic melanoma, dacarbazine has response rates of 15%-25% and in several studies, when combined with other alkylating agents, has yielded even higher response rates. Among the highest response rates are those achieved by using high-dose chemotherapy regimens combined with autologous bone marrow support (transplantation).

PURPOSE

We conducted a prospective randomized clinical trial to test the efficacy of high-dose alkylating agents in combination with autologous bone marrow support given as adjuvant therapy for high-risk stage II (World Health Organization) melanoma.

METHODS

Thirty-nine patients with metastases involving five or more lymph nodes were randomly assigned to one of two treatment arms within 8 weeks of lymphadenectomy: immediate treatment or observation only. The immediate-treatment arm consisted of 19 patients who, immediately after random assignment, received high-dose chemotherapy with alkylating agents, followed 3 days later by reinfusion of autologous bone marrow. The observation arm consisted of 20 patients who were observed until relapse (confirmed by biopsy) and were then treated with the identical high-dose alkylating agent chemotherapy followed by reinfusion of autologous bone marrow. Bone marrow was harvested from the patients under general anesthesia 1-2 weeks prior to chemotherapy and was cryopreserved. Chemotherapy consisted of intravenous administration of cyclophosphamide (1875 mg/m2 as a 1-hour infusion daily for 3 days), cisplatin (55 mg/m2 per day by continuous infusion over the same 72-hour period), and carmustine (BCNU) (600 mg/m2) given immediately after cisplatin on the 4th day as a 2-hour infusion. The total doses of the three drugs were 5625, 165, and 600 mg/m2, respectively. All patients received medical evaluations every 6-12 weeks over the study period. Kaplan-Meier estimates were used to determine the time to disease progression on the basis of intent to treat.

RESULTS

There was no statistically significant difference in overall survival or in time to disease progression between the two treatment arms. However, the median time to progression was 16 weeks in the observation arm and 35 weeks in the immediate-treatment arm.

CONCLUSIONS

Immediate adjuvant high-dose chemotherapy with alkylating agents followed by autologous bone marrow support more than doubled the time to disease progression compared with observation alone, though the difference was not statistically significant. No differences in overall survival were noted.

Lipoprotein[a] as a risk factor for preclinical atherosclerosis

Elevated mean levels of lipoprotein[a] (Lp[a]) have been associated with symptomatic cardiovascular diseases such as clinically manifest myocardial infarction (MI), coronary artery disease, restenosis of coronary artery vein grafts after bypass, and a family history of MI. Associations of Lp[a] with arterial wall thickening in asymptomatic individuals previously have not been addressed and are evaluated in this report among participants of the Atherosclerosis Risk in Communities (ARIC) Study. Intima-media wall thickening in the extracranial carotid arteries was assessed noninvasively with B-mode ultrasonography; Lp[a] was measured as its total protein component. Individuals with wall thickening > or = 90th percentile of the population maximum far-wall thickness were pair matched to participants < 75th percentile of wall thickness by race, gender, center, 10-year age group, and time of examination. These selection criteria yielded 492 matched pairs, with 395 white pairs and 97 black pairs. The mean Lp[a] protein level for all black participants was 174.6 micrograms/mL compared with 77.8 micrograms/mL for whites. Conditional logistic regression analysis for the association of Lp[a] with case-control status yielded a statistically significant prevalence odds ratio (OR) estimate of 1.49, based on a 1-SD difference in Lp[a] protein, after adjusting for age, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fibrinogen, hypertension, and cigarette smoking. None of these risk factors significantly altered the OR, in agreement with reports that Lp[a] is unaffected by environmental influences. In addition, no differential effect of Lp[a] protein on case-control status (effect modification) was observed by race, gender, low-density lipoprotein cholesterol, or fibrinogen in this population.(ABSTRACT TRUNCATED AT 250 WORDS)

[Study on human gamma-crystallins: IV. Photooxidation of fetal gamma 2-crystallin by ultra-violet irradiation]

Human fetal gamma 2-crystallin solution was irradiated by ultra-violet (UV) (lambda 365 nm) at varying time, and analysed by light scattering, SDS-PAGE with DACM, which could specifically combine to free sulphydryl, as well as tryptophan fluorescence and its quenching with acrylamide. The results showed that light scattering of gamma 2-crystallin solution increased after 24 hour irradiation; SDS-PAGE reveled formation of dimer which did not have free sulphydryl and low molecular weight peptide of gamma 2-crystallin. The tryptophan fluorescence of gamma 2-crystallin decreased, and acrylamide fluorescence quenching effect did not show significant change. It suggested that human fetal gamma 2-crystallin photooxidized by UV could aggreate by disulfide and degrated to low molecular weight peptide, and its tryptophan were also oxidized in some degree.

Effect of neuropeptide Y on natural killer activity of normal human lymphocytes

The in vitro effect of neuropeptide Y (NPY) on natural killer (NK) cell activities of normal lymphocytes was investigated. NPY at 10(-9) to 10(-12) M concentrations produced significant suppression of NK activity against K 562 target cells. NPY at 10(-9) to 10(-12) M concentrations also produced significant inhibitory effects on NK activities of NK-enriched large granular lymphocytes against LAV-infected 8E5/LAV target cells. The suppression was dose dependent against both targets. NPY-induced suppression of NK activity of lymphocytes against K 562 target cells was specifically reversed by rabbit anti-NPY antisera at 1:800 and 1:1600 dilutions, showing the specificity of reactions. Pretreatment of target cells with NPY concentrations capable of inhibiting NK activity did not affect the sensitivity of K 562 target cells for lysis by effector cells. Inhibition of cytotoxicity was not due to direct toxicity of effector cells, because lymphocytes treated with NPY showed normal levels of 51Cr release and their viability was comparable to that of untreated control cells. These studies demonstrated that NPY, a product of sympathetic nervous system activation, may have a significant immunoregulatory effect on NK cell activities of normal lymphocytes that may be of clinical significance.

Election spin resonance studies of free radical formation and oxygen consumption of lens epithelium during ultraviolet exposure

A long life election spin resonance (ESR) signal at g = 2.0006 was observed in the normal lens epithelium and cortical fibers. During ultraviolet (UV) exposure, a new ESR signal at g = 2.0060 was found in the lens epithelium. But this specific signal was not detected in the lens cortical fibers. This suggested that lens epithelial cells were more susceptible to the free radical formation which was induced by UV light. By means of ESR spin probe oximetry, the oxygen uptake of lens epithelial cells was measured. The more the oxygen uptake, the higher the K value was. The K value of the oxygen consumption of epithelial cell linearly correlated with time of consumption (20-60 min) and increased as a function of UV exposure time (1-5 min). The oxygen consumption rate of lens epithelial cell was approximately 1.38 x 10(6) and increased to 7.1 x 10(6) O2 molecules per cell per sec. The oxygen consumption rate increased more than 5 times. These results indicates that UV light can accelerate the respiratory function of lens epithelial cells. The necessity of excess oxygen of lens epithelial cells may play a role in the cataract formation induced by UV light.

Increased de novo hepatic lipogenesis in human immunodeficiency virus infection

We measured de novo lipogenesis in human immunodeficiency virus (HIV) infected men using a newly developed stable isotope method. HIV-infected subjects with a history of weight loss (n = 17, mean weight loss 14.9 +/- 3.2 kg), asymptomatic HIV-seropositive subjects with normal CD4 T-cell counts (n = 7) and healthy HIV seronegative controls (n = 11) were studied. Hepatic lipogenesis was determined by infusion of [2-13C]-acetate, using the recently described xenobiotic probe technique with mass isotopomer analysis. Hepatic acetyl-coenzyme A enrichment was measured by high performance liquid chromatography/mass spectrometry of secreted sulfamethoxazole-acetate, with measurement of incorporation into very low density lipoprotein-fatty acids by gas chromatography-mass spectrometry. Circulating tumor necrosis factor (TNF), interleukin-1 (IL-1), interferon alpha (IFN alpha), insulin, and triglycerides were measured concurrently, and 7-day weighed food records were performed. De novo hepatic lipogenesis was increased 3- to 4-fold in HIV-infected subjects with weight loss compared to normal controls (P < 0.05 for palmitate and stearate in both overnight-fasted and fed states), and was also significantly increased in asymptomatic HIV seropositive subjects. Circulating TNF and IL-1 were not measurable in any subject (detection limit 2 pg/ml for IL-1 and 20 pg/ml for TNF). Serum IFN alpha was measurable in 11 out of 17 subjects with wasting and correlated significantly with de novo lipogenesis in overnight-fasted but not fed states. Serum IFN alpha was unmeasurable in asymptomatic HIV-infected subjects despite elevated lipogenic rates. Serum triglyceride concentrations were elevated in subjects with weight loss (2.09 +/- 0.28 mmol/L) and asymptomatic HIV-positives (1.34 +/- 0.34 mmol/L) in comparison to controls (0.67 +/- 0.08 mmol/L), and correlated with lipogenesis. Food intake correlated inversely with lipogenesis in the overnight-fasted state. We conclude that HIV infection is characterized by abnormal fat anabolism. This applies to subjects with reduced lean body mass and to asymptomatic HIV-positive subjects with normal T-cell counts. The former observation may have implications for the pathophysiology and treatment of the wasting syndrome. The latter observation is consistent with activation of the immune response and a state of viral nonlatency in early HIV disease.

Methotrexate Resistance in Datura innoxia (Uptake and Metabolism of Methotrexate in Wild-Type and Resistant Cell Lines)

A wild-type Datura innoxia cell line (Px4) was used to select methotrexate-resistant cells through a stepwise procedure. Two independently selected cell lines, MTX161 and MTX132, were stable and shown to be 5 to 15 times more resistant to methotrexate than wild type. These methotrexate-resistant cells were similar to the wild-type cells in levels and kinetic properties of dihydrofolate reductase, the sensitivity of dihydrofolate reductase to methotrexate, the binding of [3H]methotrexate to soluble proteins, and the formation of methotrexate polyglutamate derivatives. High performance liquid chromatographic analyses indicated that methotrexate polyglutamylation is only slight and may not be significant in the toxicity of methotrexate to Datura cells. The uptake of methotrexate was also investigated in the wild-type and resistant cells. The Px4 cells exhibited a linear uptake that lasted for 1 to 7 h. The uptake was saturable, pH and energy dependent, and had a Km of 65.6 nM and a Vmax of 12.5 nmol h-1g-1 fresh weight. Neither MTX161 nor MTX132 exhibited the sustained uptake of methotrexate shown by the Px4 cells. As a result, there were greatly reduced concentrations of intracellular methotrexate in resistant cells. Resistant cell lines had 2- to 3-fold higher Km values for methotrexate uptake compared with Px4 cells. It is proposed that these cells became resistant as a result of a stable change in the membrane transport system for methotrexate.

Measurement of endogenous synthesis of plasma cholesterol in rats and humans using MIDA

We used the mass isotopomer distribution analysis (MIDA) technique to measure endogenous synthesis of plasma cholesterol in vivo in rats and normal human subjects. Sodium [1-13C]- or [2-13C]acetate was infused, and plasma free cholesterol was analyzed by gas chromatography-mass spectrometry. Frequencies of mass isotopomers M0-M4 (mass-to-charge ratio 368-372) were quantified. The enrichment of the true precursor for cholesterol synthesis (acetyl-coenzyme A in contributing tissues) was determined using the MIDA method. This technique remains mathematically valid even if more than one tissue contributes to circulating free cholesterol. The fractional contribution (f) from endogenous synthesis to free cholesterol in normal women (n = 5) was 2.48 +/- 0.39% after 7 h in the postabsorptive state and 1.27 +/- 0.41% after 8 h of refeeding. In ad libitum-fed rats (n = 12), f was 2.89 +/- 0.44% after 12 h, whereas administration of recombinant tumor necrosis factor increased this value fourfold. Next, the rate constant (k) for removal of labeled free cholesterol from plasma was calculated. Higher masses (M2-M4) were followed to avoid the problem of persistent label incorporation. During the 60 h after cessation of [13C]acetate infusions, k was 0.02490 +/- 0.00298/h in humans. Using these values of k and f, absolute cholesterogenesis was 568 +/- 55 mg/day in normal women (follicular menstrual phase), similar to prior estimates based on whole body sterol balances. Women also exhibited a diurnal variation for endogenous cholesterol synthesis (34.6 +/- 5.4 mg/h nighttime vs. 15.9 +/- 5.2 mg/h daytime) consistent with current knowledge about rhythms in cholesterogenesis. Checks on the model were internally consistent (e.g., comparisons among different isotopomers for calculating precursor enrichment). We conclude that fractional and absolute endogenous cholesterol synthesis can be measured using stable isotopes in vivo by the MIDA technique.

Detection of dystrophin in the postsynaptic density of rat brain and deficiency in a mouse model of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a common, lethal, chromosome X-linked inherited disease. Moderate cognitive impairment is a feature of DMD, but the underlying mechanisms are unknown. DMD is characterized by a defect in a protein, dystrophin, that is located predominantly in muscle but has been detected in brain. We sought to directly localize dystrophin within the complex synaptic structure of the cerebral cortex by focusing on the postsynaptic density (PSD), which appears to be central to synaptic function. We report that a specific anti-dystrophin antibody (anti 6-10) recognizes three distinct proteins in the purified PSD: the 400-kDa dystrophin and two previously unidentified dystrophin-related proteins of 120 and 110 kDa. These proteins exhibited differential regional expression in PSDs from cerebral cortex, cerebellum, and olfactory bulb. In the cortical PSD, the 400-kDa dystrophin was predominant, whereas the 120-kDa protein was the major species in cerebellum and olfactory bulb PSDs. The three proteins were differentially expressed in the PSD during cortical development: the 400-kDa protein exhibited a selective 9-fold increase during postnatal days 7 to 10, suggesting a normal physiological role in synaptic maturation. The PSD from the mdx mouse, a model of human DMD, contained no detectable 400-kDa dystrophin but expressed the two dystrophin-related proteins. Our results indicate that brain dystrophins are localized to the PSD, potentially as three isoforms, and raise the possibility that cognitive abnormalities in DMD are attributable to synaptic dysfunction associated with deficits in brain dystrophin molecules.

Light and electron microscopic localization of alpha subunits of GTP-binding proteins, G(o) and Gi, in the cerebral cortex and hippocampus of rat brain

Antibodies that recognize alpha subunits of G(o), Gi2 and Gi3 were used to evaluate their association with synaptic junctions. G(o), but not Gi, was concentrated within perikaryal and dendritic cytoplasm of a small population of bipolar neurons. All three G-proteins were associated with the intracellular surface of dendritic, axonal and astrocytic plasma membranes and postsynaptic densities (PSDs). However, association with PSDs was more prevalent for the two Gi's than for G(o) while the association with terminals forming putatively excitatory synapses was more prevalent for G(o) and Gi3 than for Gi2. Thus, neuromodulators may modulate the release of excitatory transmitters via activation of presynaptic Gi3 and G(o) and also regulate the opening of Ca2+ and/or K+ channels via activation of Gi's and G(o) at PSDs.

Nuclear localization signals, but not putative leucine zipper motifs, are essential for nuclear transport of hepatitis delta antigen

Hepatitis delta antigen (HDAg) is the only known protein of hepatitis delta virus and was previously shown to localize in the nucleoplasm of infected liver cells. In this study, nuclear localization signals of HDAg were defined by expressing various domains of the antigen in both hepatic and nonhepatic cells as beta-galactosidase fusion proteins. A cytochemical staining assay demonstrated that a domain from amino acid residues 35 to 88 of HDAg was able to facilitate transport to the nucleus of the originally cytoplasm-localized protein beta-galactosidase. Two nuclear localization signals, NLS1 and NLS2, which are similar to those of simian virus 40 T antigen and polyomavirus T antigen, respectively, were identified. Either NLS1 or NLS2 alone was sufficient for the nuclear transport of HDAg. However, a fusion protein (N65Z) containing beta-galactosidase and the N-terminal 65 amino acids of HDAg, containing NLS1, was localized exclusively in the cytoplasm and perinuclear region. A possible hydrophobic subdomain between amino acid residues 50 and 65 may block the function of NLS1. Nevertheless, N65Z could enter the nuclei of transfected cells when it was coexpressed with full-length HDAg. Entry into the nucleus may be mediated by the coiled-coil structure rather than the putative leucine zipper motif located between amino acid residues 35 and 65. The existence of two independent nuclear localization signals may ensure the proper functioning of HDAg in the multiplication of delta virus in the nucleus. In addition, two putative casein kinase II sites (SRSE-5 and SREE-126) that may be important in controlling the rate of nuclear transport were found in HDAg.

Occurrence of the alpha subunits of G proteins in cerebral cortex synaptic membrane and postsynaptic density fractions: modulation of ADP-ribosylation by Ca2+/calmodulin

We have examined the isolated postsynaptic density (PSD) fraction for the presence of a G protein. First, we found specific binding of guanosine 5'-[gamma-[35S]thio]triphosphate to the PSD. Second, pertussis toxin-activated ADP-ribosylation of the isolated PSD fraction resulted in the appearance of a G protein with an apparent molecular mass of 41 kDa, and two G proteins with apparent molecular masses of 41 kDa and 39 kDa in synaptic membrane (SM) fraction and total homogenate (H). The amount of the 41-kDa G protein per unit protein was in the order of SM greater than H greater than PSD. Anti-G(i0 antibodies recognized the 41-kDa G protein in both PSD and SM, whereas anti-G(o) antibodies reacted with the 39-kDa G protein in the SM. The absence of G(o) protein in the PSD suggested that there was no contamination with SM. Moreover, unlabeled PSD incubated with an extract of SM that contained the labeled G proteins resulted in no label in the subsequently reisolated PSD, suggesting that the G protein found in the PSD was not due to adsorption of the G protein onto the PSD during its isolation from the SM. PSD pretreated with EGTA gave an 11-fold increase in the ADP-ribosylation reaction of the G(i) protein; similar effects on the G(i) and G(o) proteins of SM were obtained. Restoration of Ca2+/calmodulin to the PSD, but not of either Ca2+ or calmodulin alone, removed the effect of EGTA, indicating a strong complex formation between G(i) and Ca2+/calmodulin that decreased the ADP-ribosylation reaction. Preincubation with the Ca(2+)-channel blocker nifedipine decreased the ADP-ribosylation reaction in the PSD. We conclude that G(i) is present in the PSD, that it may interact with calmodulin and that it is involved in the regulation of voltage-dependent Ca2+ channel. We present a theory of the involvement of the G protein and calmodulin in postsynaptic neurophysiological events.

Short-term intraindividual variability in hemostasis factors. The ARIC Study. Atherosclerosis Risk in Communities Intraindividual Variability Study

Recent epidemiologic studies found that there is a strong association of hemostatic factors with ischemic heart disease. The Atherosclerosis Risk in Communities (ARIC) Intraindividual Variability (IIV) Study was conducted to estimate the various components of variation in hemostasis factors measured in the ARIC Study and to estimate the measures of repeatability of these factors. A total of 39 subjects (16 men, 23 women) were studied. Each had blood collected three times, with a 1- to 2-week interval between each visit. The contributions of between-person variability, within-person (biologic) variability, and processing and assay variability were estimated. Then the reliability coefficient R was estimated as the proportion of total variance accounted for by between-person variance. The reliability coefficient can be interpreted as the correlation between measures made at repeat visits. Among the various analytes, the reliability coefficients were quite high for activated partial thromboplastin time and plasma factor VIII (R = 0.92, 0.86, respectively). Low repeatability was obtained for antithrombin III activity and protein C (R = 0.42, 0.56, respectively). The lack of repeatability for these variables derives mostly from the processing (field center and laboratory) variation. Other analytes--fibrinogen, plasma factor VII, and von Willebrand factor--were intermediate in repeatability. In comparing the analyte-specific high-level to low-level groups, no substantial difference of within-person plus method coefficient of variation between the two groups was found for any analyte except for factor VIII, whereas the corresponding variance components for most analytes were higher for the higher analyte level. Reliability coefficients from this ARIC IIV study are generally higher than those found in other studies, and this is related to the relative variations in populations studied and to the time between measurements.

Potassium iodide and acrylamide fluorescence quenching studies on gamma-crystallins of human lenses in development and aging

gamma 1-, gamma 2- and gamma 3-crystallin (corresponding to gamma s-, gamma C- and gamma D-crystallin respectively) of human fetal, 2 year and 20+ year old lenses are separated by Sephadex gel chromatography. Iodide and acrylamide are used to quench the tryptophane fluorescence of sub-gamma-crystalline fractions and Ksv and fa values are calculated. The results show that iodide has no clear quenching effects on all gamma-crystallins, the quenching effects of acrylamide on the tryptophan fluorescences of gamma 1-, gamma 2- and gamma 3-crystallin from lenses of the same age have little differences, and the quenching rates of tryptophane fluorescences of gamma 1-crystallin decreases and that of gamma 2- and gamma 3-crystallin increase with age. These results indicate that all tryptophan residues in these three gamma-crystallins lie in hydrophobic environments of molecule and their exposure degree is in the order gamma 2 < gamma 3 < gamma 1. The tryptophan exposure of gamma 2 and gamma 3 increase (gamma 2 > gamma 3) and of gamma 1 decrease with age. The age related change of gamma 1 may be related to the changing of structure or containing of new constituents. Although the tryptophan exposure in gamma 3 is higher than that in gamma 2, the change of structure with age in gamma 2 is more prominent than in gamma 3.

Comparative studies of the carbohydrate of human gamma-crystallins from fetal and adult lenses with agglutinins

Using gel chromatography of Sephadex G-75 superfine connected with Sephadex G-50 fine column, three human gamma-crystallins (gamma 1, gamma 2, gamma 3) could be obtained. Seven agglutinins (LCA, SBA, DBA, PNA, BSL, RCA and UEA) were used to detect the sugar of sub-gamma-crystallins, which had been transferred to nitrocellulose membrane and finally stained with ABC reagents and the substrate of HPR. These results suggested that gamma 2- and gamma 3-crystallins contain sugar, but gamma 1-crystallin has no sugar. There is a decrease of carbohydrate of gamma 2 and gamma 3 as the development of the lens (esp. the former). It was postulated that in gamma-crystallins (gamma 2, gamma 3) the sugar components helped stabilizing the molecular structure (folding polypeptide, prevent protein breaking). The sugar components decreased with age by the post-translation modification.

[Effects of zinc deficiency and vitamin D deficiency on bone calcification and development of rats]

Zinc deficiency rat model was made by feeding zinc deficiency diet. The level of bone calcium of the zinc deficiency rats was significantly lower than that of the control rats. Their bone cortex was thinner and bone density decreased. The counts of their cartilage cells and hypertrophic cells of epiphyseal plate were less frequent, and the diameter of their hypertrophic cells was smaller than that of the controls. It suggested that zinc deficiency caused defective bone calcification which was similar to that in vitamin D deficiency. Zinc deficiency seemed to hinder the linear growth of long bone and might be the cause of dwarf.

Molecular cloning of the transmembrane component of the 13762 mammary adenocarcinoma sialomucin complex. A new member of the epidermal growth factor superfamily

Ascites sublines of the 13762 rat mammary adenocarcinoma have a cell surface sialomucin complex composed of the sialomucin ascites sialoglycoprotein-1 (ASGP-1) and the membrane-associated glycoprotein ASGP-2. The sialomucin complex is synthesized as a high M(r) precursor, pre-sialomucin complex (pSMC-1). To characterize the structure of the membrane-associated component of this complex, a lambda gt11 cDNA expression library was constructed using mRNA from 13762 rat mammary adenocarcinoma cells and screened with polyclonal antibody against ASGP-2. The strongest antibody-binding clone, designated lambda ASGP2.9-1, had a 1.3-kilobase (kb) insert, and hybridized to a 9-kb transcript in 13762 cell mRNA. The large size of this transcript was expected, since the estimated molecular mass of pSMC-1 is greater than 250 kDa. To obtain the full sequence of ASGP-2, a longer cDNA (5.4 kb), designated pASGP1/2.1, was subsequently cloned by screening a plasmid library with an oligonucleotide complementary to the 5' end of the phage insert. The amino acid sequence derived from nucleotide sequence of pASGP1/2.1 showed a 12-amino acid identity with amino acid sequence obtained from the NH2 terminus of ASGP-2, indicating the entire ASGP-2 coding region was included in the cDNA. Furthermore, an 18-amino acid identity with the NH2 terminus of a 6-kDa CNBr fragment of ASGP-2 was also observed in the cDNA sequence. The polypeptide contains several distinct domains, including a hydrophobic transmembrane domain, a short (20 residue) COOH-terminal cytoplasmic tail, and a large extracellular domain with 24 potential N-glycosylation sites. These properties correspond to features of ASGP-2 and pSMC-1 predicted by previous biochemical studies. Most interestingly, the extracellular domain contains two cysteine-rich sequences, each of which has a segment with strong similarities to proteins with epidermal growth factor activity. Since our recent studies show that ASGP-2 can modulate epidermal growth factor receptor phosphorylation activity, these results provide structural evidence to support the role of the heterodimeric sialomucin complex as a bifunctional modulator of cellular interactions and cell proliferation.

[Studies on human gamma-crystallins. I. Quantitative changes with age and cataract formation]

Water soluble protein from human lenses at various ages are separated by Sephadex gel chromatography. The results show that there are major three gamma-crystallins (gamma 1, gamma 2, gamma 3) in human lenses. In normal lenses the total contents of the three gamma-crystallins in water soluble fraction of lens proteins keep stable as age increases. However, among the three gamma-crystallins, gamma 1 increase and gamma 2 decrease markedly, and very little change with gamma 3 are found as age increases. In nuclear cataractous lenses, all three gamma-crystallins decrease as compared with the normal lenses of the same age. The variety of synthesis of each gamma-crystallin is mainly responsible for the changes of their quantities. It is postulated that the total low molecular weight crystallin contents in water soluble proteins of the human lens is related to the transparency of lens. The structural characterization of gamma 3-crystallin is responsible for the relative constant as age increases.

Effects of recombinant monokines on hepatic pyruvate dehydrogenase, pyruvate dehydrogenase kinase, lipogenesis de novo and plasma triacylglycerols. Abolition by prior fasting

1. The effects of recombinant human tumour necrosis factor alpha (TNF) and murine interleukin-1 alpha (IL-1) on the activation state of the hepatic pyruvate dehydrogenase complex (PDHa), the activity of mitochondrial PDH kinase, hepatic lipogenesis de novo and plasma triacylglycerol (TG) concentrations were studied. 2. Monokine effects depended upon prior nutritional state. In rats fasted for 20 h or 45 h before monokine administration and refeeding (orally or with intravenous glucose), PDHa, TG and hepatic lipogenesis were not increased. In rats fed ad libitum, treatment with TNF plus IL-1 increased the contribution of hepatic lipogenesis to circulating TG to 550% of control values (P = 0.03) and plasma TG concentrations to 159% (P = 0.02), whereas PDHa increased slightly to 120% (P = 0.02) and liver glycogen content fell to 45.8% (P = 0.05) of control values. 3. Intrinsic hepatic PDH kinase activity was not changed by monokine treatment in rats fed ad libitum. 4. The increased lipogenesis de novo showed no correlation (r2 = 0.05, not significant) with hepatic PDHa in individual animals fed ad libitum. 5. In conclusion, these results suggest that monokines increase pyruvate flux through hepatic PDH in vivo in rats fed ad libitum primarily by mechanisms other than covalent modification of PDH. Prior nutritional status exerts a permissive effect for monokine stimulation of PDHa and lipogenesis, consistent with a substrate-mediated action, but the mechanism of this permissive effect remains uncertain.

On the identity of the major postsynaptic density protein

Increasing evidence suggests that the postsynaptic density (PSD) plays a critical role in synaptic communication and plasticity. The major PSD protein (mPSDp), a calcium/calmodulin-dependent protein kinase, appears to be central to PSD function. The mPSDp has long been considered identical to the alpha subunit of the soluble calmodulin kinase II (alpha-CKII). However, mPSDp and alpha-CKII do differ in solubility and antigenicity, raising the possibility that the two proteins are distinct. To further define the relationship between the two proteins, we purified the mPSDp to homogeneity from adult rat cerebral cortex and compared the proteins. In contrast to alpha-CKII, the purified mPSDp was insoluble in high concentrations of salt, various detergents, chelators of divalent cations, and the strong denaturant guanidine hydrochloride. The pI value of the mPSDp was 6.2, whereas that of alpha-CKII was 6.7-7.2. The purified mPSDp bound calmodulin in the presence of Ca2+ and was autophosphorylated in a Ca2+/calmodulin-dependent manner. Polyclonal antiserum raised against mPSDp (anti-mPSDp) recognized purified mPSDp or mPSDp in synaptic membrane, indicating immunologic specificity among the synaptic proteins. Anti-mPSDp did not recognize alpha-CKII, whereas anti-alpha-CKII antibodies reacted only weakly with mPSDp, suggesting that the proteins are distinct but structurally similar. Moreover, sequence analysis of protease V8-digested polypeptides revealed that there was at least an 8-amino acid sequence, MLKVPNIS, that is not present in alpha-CKII. Finally, HPLC analysis of V8-digested fragments of mPSDp and alpha-CKII in parallel revealed dissimilar peptide patterns. Thus our observations suggest that mPSDp and alpha-CKII are similar but not identical. The unique physicochemical and structural properties of the mPSDp may provide insights into molecular mechanisms mediating synaptic plasticity.

Mechanisms of fructose-induced hypertriglyceridaemia in the rat. Activation of hepatic pyruvate dehydrogenase through inhibition of pyruvate dehydrogenase kinase

1. The effects of purified diets containing 70% glucose or 70% fructose on the activation state of hepatic pyruvate dehydrogenase (PDHa), activity of mitochondrial PDH kinase, plasma triacylglycerols (TG) and hepatic lipogenesis de novo in rats were measured. 2. Plasma TG were significantly increased in the fructose-fed compared with the glucose-fed group (125 +/- 45 mg/dl versus 57 +/- 19 mg/dl; P less than 0.002) after 3-5 weeks on the diet despite less daily food intake. 3. Hepatic PDHa in fructose-fed rats was 144% of the value in glucose-fed rats (15.4 +/- 1.2% versus 10.7 +/- 0.5%; P less than 0.002), whereas cardiac muscle PDHa was not different (45.5 +/- 6.6% versus 41.0 +/- 7.8%). 4. Intrinsic hepatic PDH kinase activity was decreased to 34% of glucose-fed values by fructose feeding (-k = 3.56 +/- 0.39 versus 10.41 +/- 1.85 min-1; P less than 0.005). 5. The fractional contribution to very-low-density-lipoprotein palmitate from hepatic lipogenesis de novo, measured by a stable-isotope mass-spectrometric method, was 10.49 +/- 2.42% (n = 8) in fructose-fed rats versus 5.55 +/- 1.38% (n = 9) in glucose-fed rats (P less than 0.05), and 2.66 +/- 2.39% (n = 3) in chow-fed rats (P less than 0.05 versus fructose-fed group). The absolute contribution to circulating TG from lipogenesis de novo was also significantly higher in the fructose-fed than in the glucose-fed group (14.9 +/- 5.1 mg/dl versus 2.9 +/- 0.6 mg/dl; P less than 0.05) 6. Portal insulin concentrations were significantly higher in the fructose-fed rats (206 +/- 49 mu-units/ml versus 81 +/- 15 mu-units/ml; P less than 0.05). 7. In conclusion, dietary fructose appears to have a specific activating effect on hepatic PDH, mediated at least in part by inhibition of PDH kinase. These results are consistent with increased flux through hepatic PDH and synthesis of new fat, not just increased re-esterification of non-esterified fatty acids.

Gender recognition from speech. Part II: Fine analysis

The purpose of this research was to investigate the potential effectiveness of digital speech processing and pattern recognition techniques for the automatic recognition of gender from speech. In part I Coarse Analysis [K. Wu and D. G. Childers, J. Acoust. Soc. Am. 90, 1828-1840 (1991)] various feature vectors and distance measures were examined to determine their appropriateness for recognizing a speaker's gender from vowels, unvoiced fricatives, and voiced fricatives. One recognition scheme based on feature vectors extracted from vowels achieved 100% correct recognition of the speaker's gender using a database of 52 speakers (27 male and 25 female). In this paper a detailed, fine analysis of the characteristics of vowels is performed, including formant frequencies, bandwidths, and amplitudes, as well as speaker fundamental frequency of voicing. The fine analysis used a pitch synchronous closed-phase analysis technique. Detailed formant features, including frequencies, bandwidths, and amplitudes, were extracted by a closed-phase weighted recursive least-squares method that employed a variable forgetting factor, i.e., WRLS-VFF. The electroglottograph signal was used to locate the closed-phase portion of the speech signal. A two-way statistical analysis of variance (ANOVA) was performed to test the differences between gender features. The relative importance of grouped vowel features was evaluated by a pattern recognition approach. Numerous interesting results were obtained, including the fact that the second formant frequency was a slightly better recognizer of gender than fundamental frequency, giving 98.1% versus 96.2% correct recognition, respectively. The statistical tests indicated that the spectra for female speakers had a steeper slope (or tilt) than that for males. The results suggest that redundant gender information was imbedded in the fundamental frequency and vocal tract resonance characteristics. The feature vectors for female voices were observed to have higher within-group variations than those for male voices. The data in this study were also used to replicate portions of the Peterson and Barney [J. Acoust. Soc. Am. 24, 175-184 (1952)] study of vowels for male and female speakers.

Use of mass isotopomer distributions in secreted lipids to sample lipogenic acetyl-CoA pool in vivo in humans

Measurement of hepatic fatty acid (FA) and cholesterol synthesis has been limited by lack of access to the precursor pool, cytosolic acetyl-CoA. We present a method for inferring the enrichment of the true hepatic lipogenic precursor pool in humans using the frequency distribution of mass isotopomers within enriched circulating polymers of acetyl-CoA [very low-density lipoprotein (VLDL)-palmitate, VLDL-stearate]. Human subjects were infused intravenously (n = 16) with [1-13C]- or [2-13C]acetate. Oral sulfamethoxazole (SMX) was administered concurrently, and the acetylated conjugate (SMX acetate) was used to estimate independently the hepatic cytosolic acetyl-CoA enrichment. Isotopomer frequencies in VLDL-FA were determined by gas chromatography-mass spectrometry, whereas high-performance liquid chromatography-mass spectrometry was used to measure enrichments in SMX acetate. Based on the excess M2/excess M1 ratio in VLDL-FA, calculated acetyl-CoA enrichments were 5.59 +/- 0.33 molar percent excess (MPE), whereas SMX acetate enrichments were 5.38 +/- 0.31 MPE (the 2 methods were not significantly different). Mass isotopomer-calculated and SMX acetate-measured estimates of acetyl-CoA enrichments correlated very closely in individual subjects (r2 = 0.93; P less than 0.0001). De novo hepatic lipogenesis can be measured using isotopomer-calculated precursor enrichments compared with measured incorporation in specific isotopomers of VLDL-FA. In summary, excess isotopomer frequencies in secreted lipids provide a non-invasive technique for estimating hepatic cytosolic acetyl-CoA enrichments in humans in vivo and correlate closely with enrichments observed using the xenobiotic probe technique. Isotopomeric distributions represent a new strategy for accurate measurement of macromolecule synthesis that may be applicable to other classes of molecules besides lipids.

[Change of T lymphocyte subsets in peripherial blood of children with malnutrition and zinc deficiency]

Sixty children with malnutrition were investigated in this study. The results showed a reduction of serum zinc in moderate and severe cases compared with the mild and normal groups. OKT3+, OKT4+ and OKT8+ cells in peripheral blood of mild malnutrition were significantly decreased in contrast to normal control. The reductive degree of OKT8+ and OKT4+ cells correlated with the severity of malnutrition. OKT8+, OKT4+ and OKT4+/OKT8+ ratio of moderate and severe malnutrition with infection were much lower than those without infection. Our findings suggested that main effective and regulative cells of cell-mediated immunity were impaired. OKT3+ and OKT4+ cells might be used as a sensitive index for early assessment of the immune function in malnutrition children.

Sampling the lipogenic hepatic acetyl-CoA pool in vivo in the rat. Comparison of xenobiotic probe to values predicted from isotopomeric distribution in circulating lipids and measurement of lipogenesis and acetyl-CoA dilution

The acetylation of xenobiotics may provide a means for sampling hepatic cytosolic acetyl-CoA in vivo for isotopic studies of lipogenesis. Here, we test the accuracy of acetylated-sulfamethoxazole (SMX) in representing the true precursor pool for hepatic lipogenesis by comparison to a mathematical technique for estimating acetyl-CoA enrichment using the mass isotopomer distribution in circulating lipids. We then go on to measure hepatic fatty acid synthesis in intact rats using stable and radioisotopes. Specific activities and enrichments of SMX-acetate (the latter determined by high performance liquid chromatography-mass spectrometry) were monitored during fasting and refeeding. The dilution rate of hepatic acetyl-CoA relative to infused 13C- or 14C-acetates was 0.158-0.200 mmol/kg body weight/min during fasting, and did not increase significantly in rats refed with intravenous glucose at 25-30 mg/kg/min or refed ad libitum with chow, suggesting little additional input of acetate units. Plasma beta-hydroxybutyrate specific activity was much lower than SMX-acetate. The isotopomeric frequency distributions in circulating very low density lipoprotein (VLDL)-palmitate and VLDL-stearate were used to estimate the enrichment of the true precursor, hepatic acetyl-CoA, from a model based on the binomial distribution. The calculated acetyl-CoA values (7.28 +/- 0.49 molar percent excess (n = 16] based on isotopomeric frequencies were very close to measured SMX-acetate enrichments (7.44 +/- 0.41 molar percent excess (n = 21] and values within individual animals (n = 14) correlated very well (r2 = 0.90, p less than 0.0001). The contribution of VLDL-fatty acid by the de novo lipogenic pathway was similar using the stable isotope approach or radioisotopes (only 1-2% in fasted or intravenous glucose refed rats, 5% in chow refed). Combining fractional de novo lipogenesis values with absolute de novo lipogenesis rates allows estimation of total VLDL-triglyceride synthesis. In conclusion, the xenobiotic acetylation technique provides continuous access to the lipogenic hepatic acetyl-CoA pool in vivo and permits measurement of fatty acid synthesis. Isotopomer ratios in secreted lipids provide another method for estimating true precursor acetyl-CoA enrichments.

Three MDBP sites in the immediate-early enhancer-promoter region of human cytomegalovirus

MDBP, a mammalian sequence-specific DNA-binding protein, was found to recognize two sites in the major immediate-early (IE) enhancer of human cytomegalovirus. The recognition sequence for MDBP at each of these sites was localized to 14 bp by studying the effects of limited G methylation, depurination, depyrimidination, or deoxyribose modification on the ability of these sites to bind to MDBP. In addition to the two high-affinity MDBP sites in the enhancer, one low-affinity MDBP site was detected 5 bp after the transcription initiating residue of this IE transcription unit. The possible biological significance of the two enhancer MDBP sites and the downstream MDBP site is discussed.

Fraction of hepatic cytosolic acetyl-CoA derived from glucose in vivo: relation to PDH phosphorylation state

We measured the contribution of glucose to hepatic cytosolic acetyl-CoA in vivo in rats and compared it with the phosphorylation state of a potentially regulatory enzyme complex [pyruvate dehydrogenase (PDH)]. Xenobiotic probes were used to sample hepatic cytosolic acetyl-CoA [acetylated sulfamethoxazole (SMX)] and UDP-glucose (glucuronidated acetaminophen) in vivo during [U-14C]glucose infusions. Percent active (dephosphorylated) form of PDH (PDHa) was determined on freeze-clamped liver. First, we confirmed using liver cell elutriation that acetylation of SMX occurs in parenchymal hepatocytes. Next, the fraction of cytosolic acetyl-CoA derived from [14C]glucose in vivo was shown to depend on dietary state. Specific activity of acetyl-CoA relative to plasma glucose or hepatic UDP-glucose was lower after 48 h fasting than after overnight fasting, and glucose refeeding (25 mg.kg-1.min-1 iv) maximally increased [14C]-glucose fractional contribution to acetyl-CoA within 2 h in the overnight-fasted but not in the prolonged fasted group. Hepatic PDHa demonstrated a similar but not identical pattern. The isotopic and enzymatic parameters showed significant correlations (r2 = 0.61 in 48-h fasted-refed group, r2 = 0.28 in overnight-fasted refed group), although [14C]glucose contribution to acetyl-CoA increased disproportionately compared with PDHa as refeeding progressed. The indirect pathway of UDP-glucose synthesis correlated inversely with the fractional contribution of glucose to acetyl-CoA. In summary, the fraction of hepatic acetyl-CoA derived from glucose in vivo is influenced by acute and chronic dietary factors and is only partially explained by PDHa. Regulation of the carbon source of hepatic acetyl-CoA in vivo and interactions suggested by these results (e.g., glucose-fatty acid cycle; branch-point regulation of glucose recycling) can be addressed in a quantitative fashion using this experimental framework.

Measurement of de novo hepatic lipogenesis in humans using stable isotopes

Direct measurement of de novo lipogenesis has not previously been possible in humans. We measured de novo hepatic lipogenesis in normal men by means of stable isotopes and by combining the acetylated-xenobiotic probe technique with mass isotopomer analysis of secreted very low density lipoprotein-fatty acids (VLDL-FA). Sulfamethoxazole (SMX) was administered with [13C]acetate during an overnight fast followed by refeeding with intravenous glucose (7-10 mg/kg of weight per min), oral Ensure (7-10 mg of carbohydrate/kg of weight per min), or a high-carbohydrate mixed-meal breakfast (3.5 g of carbohydrate/kg of weight). Respiratory quotients remained less than 1.0. High-performance liquid chromatography/mass spectrometry-determined enrichments in SMX-acetate attained stable plateau values, and hepatic acetyl-coenzyme A (CoA) dilution rate did not increase with refeeding (approximately 0.024 mmol/kg per min). The fraction of VLDL-palmitate derived from de novo lipogenesis was only 0.91 +/- 0.27% (fasted) and 1.64-1.97% (fed). For stearate, this was 0.37 +/- 0.08% and 0.47-0.64%. Precursor enrichments predicted from isotopomer ratios were close to measured SMX-acetate enrichments, indicating that SMX-acetate samples the true lipogenic acetyl-CoA pool. Stearate synthesis was less than palmitate and the two did not move in parallel. Estimated total VLDL-FA synthesis is less than 500 mg/day. Thus, de novo hepatic lipogenesis is a quantitatively minor pathway, consistent with gas exchange estimates; fatty acid futile cycling (oxidation/resynthesis) is not thermogenically significant; and synthesis rates of different nonessential fatty acids by human liver are not identical in nonoverfed normal men. The contribution and regulation of de novo lipogenesis in other settings can be studied using this technique.

[Effect of human fibroblast derived inhibitor on tumor and transformed cell proliferation and differentiation]

The effect of HFDI (human fibroblast derived inhibitor) on cell growth inhibition and differentiation of J6-1 (leukemia cell line). Namalva (Burkitt's lymphoma cell line), and fresh leukemic bone marrow cell cultures was studied. HFDI was found to inhibit tumor and leukemic cell growth as assayed by 3H-TdR incorporation, cell degeneration and necrosis, and to induce differentiation. We demonstrated that the characteristics of PHA-inhibited lymphocyte transformation were, in fact, identical to those of HFDI-inhibited degeneration and necrosis and HFDI-induced differentiation. It seems that necrosis was related to target cell sensitivity to HFDI.

Liquid chromatography/mass spectrometry of plasma glucose and secreted glucuronate for metabolic studies in humans

Negative ion thermospray liquid chromatographic/mass spectrometric methods have been developed for the determination of isotopic enrichments for glucose and acetaminophen-uridine diphosphate glucuronate from (1-2H1)glucose, (1-2H1)galactose and (2-13C)acetate in humans. The error of estimate ranged from below 1% to 5%. The advantages of the method include fast analysis (up to 35 per hour), eased sample preparation, good precision, sensitivity comparable with gas chromatography/mass spectrometry and better than with isotope ratio mass spectrometry.

Effect of septal kindling on glutamate binding and calcium/calmodulin-dependent phosphorylation in a postsynaptic density fraction isolated from rat cerebral cortex

Postsynaptic density (PSD) fractions were isolated from the cerebral cortices of control and kindled rats and assayed for glutamate and gamma-aminobutyric acid-binding capacities and for the Ca2+/calmodulin-dependent protein kinase. Glutamate binding was found to be increased by approximately 50% in the PSDs isolated from kindled rats as compared to controls; this increase was almost completely from an increase in Bmax; Kd decreased only slightly. Studies with inhibitors indicate that the receptors involved were of the N-methyl-D-aspartate and quisqualate types. PSDs isolated from control and kindled rats did not differ in gamma-aminobutyric acid or flunitrazepam binding. The in vitro autophosphorylation of the Ca2+/calmodulin-dependent protein kinase was depressed by 45-76% in PSDs isolated from kindled rats as compared to controls, with little change in amount of the kinase. Therefore, we infer that (i) the kindled state is associated with an increase in glutamate activation of postsynaptic sites, allowing Ca2+ to enter dendritic spines, (ii) a change has occurred in activity of the protein kinase, which is the major cerebral cortex PSD protein, and (iii) perhaps major alterations in the PSD are a concomitant to the long-lasting nature of the kindled state.