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PubMed1997

Hair sulfur amino acid analysis.

This overview emphasizes present aspects of sulfur-containing amino acids in hair. A selection of analytical procedures to determine cystine, cysteine, S-sulfocysteine, cystine oxide, cysteic acid, lanthionine and lysinoalanine are presented. The methods relate to intact hair or partial and total hydrolysates and comprise chromatography, titration, colorimetry, polarography and spectroscopy. For the analysis of cysteine, cystine and cystine oxides, polarography and spectroscopy are the methods of choice. Cysteic acid, lanthionine and lysinoalanine are analysed by means of ion-exchange chromatography (Spackman et al., 1958) after total hydrolysis.

Alkalies↗

PubMed1985

The colorimetric determination of cyanide in human food and animal feed.

The well-known Kröller method for the determination of cyanide requires the use of the harmful chemicals benzidine (carcinogenic) and bromine (toxic) in the colorimetric part; the analytical result depends strongly on the conduct of the liberation procedure. The substitution of barbituric acid and N-chlorosuccinimide for benzidine and bromine has been investigated. The reproducibility of both colorimetric reactions is similar, but the sensitivity of the barbituric acid colorimetry is approximately 50% higher. A reproducible liberation yield can be obtained by a proper control of the heating programme. The detection limit for cyanide in a solution is approximately equal to 10 micrograms/l.

Animal Feed↗

PubMed1983

Determinants of bumetanide response in the dog: effect of probenecid.

The pharmacokinetics and pharmacodynamics of intravenous bumetanide (0.250 mg/kg), alone (treatment I) and after probenecid pretreatment (treatment II), were studied in four mongrel dogs. Lactated Ringer's solution was administered by vein throughout both treatments at a flow rate of 2 ml/min to avoid fluid and electrolyte depletion. Bumetanide and probenecid concentrations were analyzed by HPLC, sodium by flame photometry, and creatinine by colorimetry. Although the probenecid markedly reduced the plasma and renal clearances of bumetanide, as well as the fraction excreted unchanged in the urine, there was no significant difference between treatments I and II in the 4-hr natriuretic and diuretic responses. However, analysis of the dose-response curves between treatments I and II showed that sodium excretion was better correlated with bumetanide urinary excretion rate than with plasma concentration. The reasons for a poor correlation between treatments during the early time periods are discussed.

Animals↗

PubMed1995

Comparison between ion chromatography and a spectrophotometric method for determination of nitrates in meat products.

Ion chromatography and colorimetry were used to determine nitrate ion concentration in 76 different pork meat products (salami, mortadella, wurstel, raw and cooked ham and other whole-muscle cooked products) and the results were compared. The comparison revealed that the two techniques yield quantitatively similar results, except in cases where the matrix was so complex that it might have influenced the analytical data. These results are consistent with those obtained by other authors who used UV spectrophotometric detection.

Animals↗

PubMed1990

Development of rancidity in salmonoid steaks during retail display. A comparison of practical storage life of wild salmon and farmed rainbow trout.

The quality of wild salmon and farmed rainbow trout from aquaculture, both packed in transparent vacuum-skin packaging, was followed during storage for 6 months in an illuminated freezer cabinet (product temperature -17 degrees C, half of the packs protected against light, and half of the packs fully exposed to light), combining (a) colour determination of the carotenoid-pigment flesh by tristimulus colorimetry, (b) determination of thiobarbituric-acid-reactive substances (TBA value), (c) carotenoid analysis and, at the end of the storage experiment, (d) sensory evaluation. Rancidity developed faster in steaks of wild salmon (TBA increased during 6 months of storage from 2.8 mumols malonaldehyde/kg flesh to 12.5 mumols/kg for light-protected packages, and to 17.6 mumols/kg for packages exposed to fluorescent light) as compared to steaks of farmed rainbow trout (TBA increased from 1.2 to 5.8 mumols/kg, independent of light exposure), a finding also confirmed by sensory evaluation. In both products, the carotenoid pigment was identified as astaxanthin; salmon steaks, the product more susceptible to developing rancidity, had the lower astaxanthin content (rainbow trout 9.1 mg/kg flesh, salmon 4.9 mg/kg, prior to storage). While the astaxanthin content remained virtually constant in salmon steaks during storage, the content decreased significantly in steaks of rainbow trout, an observation which suggests the role of astaxanthin as a sacrificial protector against radical processes.

Animals↗

PubMed1993

Potential usefulness of hydrogen breath test with D-xylose in clinical management of intestinal malabsorption.

Hydrogen breath tests (H2 BT) have been used extensively to investigate intestinal disaccharidase deficiencies. A potentially useful test for assessing intestinal absorptive function, the H2 BT with D-xylose (H2 BT-D-xylose), has received scant attention. We report here the results of our investigation of this test in 45 patients. Fifteen patients had proved malabsorption that was due to nontropical sprue in nine, and to lymphoma, Whipple's disease, or giardiasis in the remainder. Nine patients had small-bowel bacterial overgrowth secondary to either postsurgical sequelae or intestinal dysmotility. Twenty-one patients with irritable bowel syndrome and 21 healthy individuals served as control groups. All participants ingested 25 g of D-xylose, and alveolar breath samples were obtained thereafter at 30 min intervals for 5 hr. Breath H2 was measured by chromatography. Basal H2 production, peak change (delta) and area under the curve (AUC) were calculated. Simultaneously, 5-hr urinary excretion of D-xylose was measured by colorimetry and served as the reference test. In healthy individuals, D-xylose ingestion increased H2 production (delta = 5.8 +/- 1.4 ppm, P < 0.001). Changes were similar in patients with the irritable bowel syndrome. In contrast, the increase was of a much greater magnitude in the malabsorption group (delta = 49.9 +/- 7.2 ppm, P < 0.001 vs healthy controls). AUC analysis yielded comparable results. Test performance analysis showed that, in malabsorption the H2 BT-D-xylose had a sensitivity index of 0.86, which was identical to that of the urinary D-xylose test. Specificity was 1 and 0.95, respectively; and predictability 1 and 0.93, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Clinical applicability of shortened D-xylose breath test for diagnosis of intestinal malabsorption.

Urinary and/or plasmatic D-xylose tests are broadly used in clinical practice for the diagnosis of intestinal malabsorption. A 5-hr hydrogen breath test (H2 BT) has also proven useful. Our goal was to determine whether a shorter, hence more efficient, 3-hr test would perform as well as the 5-hr test. We studied 33 patients with proven malabsorption, 44 patients with irritable bowel syndrome (IBS), and 27 healthy subjects. Each individual ingested 25 g of D-xylose, and alveolar breath samples were obtained thereafter at 30 min intervals for 5 hr. Breath samples were analyzed for H2 by gas chromatography. Individual peak delta changes and area under the curve (AUC) were calculated. Simultaneously, the 5-hr cumulative urinary excretion of D-xylose was measured by colorimetry. Results of 5-hr tests were compared with those of the first 3 hrs. In the malabsorption group, the 5-hr test showed a markedly enhanced production of H2 relative to healthy controls (delta: 60.7 +/- 6.4 vs 7.7 +/- 1.5 and AUC: 8465.0 +/- 985.4 vs 393.2 +/- 232.6, P < 0.001). Results in IBS patients did not differ from those in healthy controls. Three-hour analysis also reflected an enhanced production of H2 in the malabsorption group (delta: 45.4 +/- 6.4 and AUC: 3700.0 +/- 545.6, P < 0.001 vs healthy controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1996

Follow-up of celiac disease with D-xylose breath test.

Hydrogen breath tests (H2-BT) are commonly used to diagnose carbohydrate malabsorption. Specifically, the H2-BT with D-xylose has been shown to be as valid as the traditional urinary test for the recognition of intestinal malabsorption. We have now investigated the H2-BT with D-xylose in the follow-up of patients with celiac disease. Seventeen patients with celiac disease established clinically and confirmed by jejunal biopsy were studied. H2-BT was performed before and after treatment with a gluten-free diet for at least five months. Alveolar breath samples were obtained before administering orally 25 g of D-xylose and thereafter at 30 min intervals for 5 hr. Samples were analyzed for H2 by chromatography. Simultaneously, the 5-hr urinary excretion of D-xylose was determined by colorimetry. Gluten removal significantly decreased the H2 delta change (from 56.5 +/- 5.9 ppm to 32.2 +/- 8.8, P < 0.05). A similar decrease was observed in the area under the curve (P < 0.05). Conversely, urinary D-xylose excretion increased significantly (P < 0.05). Eleven of the 17 celiacs clinically improved after treatment. The H2-BT normalized in every patient who entered remission on the gluten-free diet, whereas the urinary D-xylose excretion remained abnormal in six of them. In the six nonresponder patients the H2-BT remained high in five, whereas urinary D-xylose excretion paradoxically normalized in 2. We conclude that H2-BT with D-xylose is a useful and practical test for the follow-up of celiac disease and is simpler and more reliable than the urinary D-xylose test.

Adolescent↗

PubMed1975

Studies of the clinical application of serum leucine aminopeptidase (LAP) activity determined with leucinamide as substrate.

A new method was presented for the determination of leucine aminopeptidase (LAP). The principle of the method consisted in the measurement of ammonia liberated by the action of LAP with direct colorimetry. Leucine naphthylamide has been widely used as substrate for the determination of LAP (Nap-method), but leucineamide was used (NH3-method) in this study, and the enzyme activities determined by the both methods were compared in various diseases. Serum LAP activity in acute hepatitis was much higher in NH3-method than in Nap-method, but the activity in obstructive jaundice was much higher in the latter than in the former. It was demonstrated that the serum of normal rats and CCl4 treated rats contained isozymes (LAP-I and II) which showed the different substrate specificities toward leucinamide and leucine naphthylamide. LAP-I activity was much higher, but LAP-II activity was much lower in the NH3-method than in the Nap-method. LAP-I activity was remarkably elevated by the NH3-method, but not by the Nap-method in the serum of CCl4 treated rats. The results suggested that leucinamide was preferable substrate for the measurements of activities of serum LAP in the clinical examinations.

Ammonia↗

PubMed2002

The effect of beta-amyloid on neurons and the influence of glucocorticoid and age on such effect.

To explore the relationship between beta-amyloid (A beta) and the pathogenesis of Alzheimer disease (AD), after injection of beta-amyloid into the rat brain, the apoptosis of nerve cells and acetylcholine (Ach) content in rat hippocampus were examined by employing TUNEL technique and base hydroxylamine colorimetry respectively. The influence of age and glucocorticoid on the neurotoxic effect of A beta was also analyzed. A beta peptide could strongly induce the apoptosis of neurons in hippocampus, cortex and striate body (P < 0.05 or P < 0.01). In addition, the senility and glucocorticoid pre-treatment could enhance the toxic effect of A beta (P < 0.05 or P < 0.01). It is concluded that A beta may play an important role in the pathogenesis of Alzheimer disease via its induction of apoptosis of neurons and by decreasing the content of the Ach.

Acetylcholine↗

PubMed2003

Role of adrenomedullin in congenital heart disease associated with pulmonary hypertension.

The changes of adrenomedullin (ADM), endothelin-1 (ET-1) and nitric oxide (NO) levels before and after operation in congenital heart disease (CHD) associated with pulmonary hypertension (PH) were observed in order to investigate their role in CHD with PH and their clinical significance. The CHD patients were divided into 3 groups according to pulmonary artery systolic pressure (PASP): Non-PH group: PASP < or = 30 mmHg (n = 11); mild-PH group: PASP 31-49 mmHg (n = 10); moderate or severe-PH group: PASP > or = 50 mmHg (n = 12). The control group consisted of 15 health children. Plasma ADM, ET-1 and NO levels were determined by radioimmunoassay and colorimetry methods. The correlation between ADM and ET-1, NO, PASP was analyzed. The changes in plasma ADM, ET-1 and plasma NO on the 7th day after operation among the groups were compared. The results showed that plasma ADM levels in non-PH group were significantly higher than that in control group (P < 0.05), but there was no significant difference in ET-1 and NO levels between the two groups (P > 0.05). ADM and ET-1 levels in mild-PH group were significantly elevated as compared with those in non-PH group (both P < 0.05), but NO levels were decreased (P < 0.05). ADM and ET-1 levels in moderate or severe-PH groups were increased as compared with those in mild-PH group (both P < 0.01), but NO level significantly declined (P < 0.05). On the 7th day after operation, plasma ADM and ET-1 levels in PH group were significantly decreased (P < 0.05, P < 0.01) as compared with those before operation, but there was no significant difference in NO levels (P > 0.05). But NO levels in non-PH group were significantly increased (P < 0.05). Plasma ADM levels in CHD were positively correlated with PASP and ET-1 (r = 0.77, P < 0.01; r = 0.82, P < 0.01), negatively correlated with NO (r = -0.56, P < 0.05). It was concluded that during the progression of PH in the cases of CHD, plasma ADM, ET-1 and NO might play an important role in the development of PH. The increased ADM may represent a compensatory mechanism. It can interact with NO and ET-1 to regulate pulmonary circulation in the pathophysiology of PH with CHD. ADM may be involved in the defence mechanism against further increase of pulmonary arterial pressure. ADM could be used as a reliable indicator of the severity of CHD associated PH.

Adolescent↗

PubMed2006

Smac/DIABLO promotes mitomycin C-induced apoptosis of bladder cancer T24 cells.

The enhancing effects of Smac gene on the mitomycin C-induced apoptosis of the bladder cancer cell line T24 were investigated. The Smac gene was transfected into bladder cancer cell line T24 under the induction of liposome. The intrinsic Smac level was detected by using immunohistochemistry and RT-PCR. The in vitro cellular growth activities were assayed by MTT colorimetry. Apoptosis was assayed by the flow cytometry. The results showed that as compared with the control cells, the apoptosis rate of T24 cells induced by mitomycin C was enhanced by transfected Smac gene. Flow cytometry revealed that, the apoptosis rate was 18.84% and 33.52%, and 10.72% and 26.24% respectively in blank and transfected cells treated with 0.05 or 0.005 mg/mL mitomycin C (P < 0.05). It was concluded that Smac could enhance the apoptosis of T24 by mitomycin C, which could provide a useful experimental evidence for bladder cancer therapy.

Apoptosis↗

PubMed2006

Study on effects of extracts from Salvia Miltiorrhiza and Curcuma Longa in inhibiting phosphorylated extracellular signal regulated kinase expression in rat's hepatic stellate cells.

OBJECTIVE: To study the effect of salvianolic acid B (SAB) and curcumin, the extracts of Salvia Miltiorrhiza and Curcuma Longa, on the proliferation and activation of hepatic stellate cell (HSC), and the extracellular signal regulated kinase (ERK) expression in it. METHODS: Rat's HSC-T6 were cultured and treated by SAB or curcumin. The inhibitory effect on cell proliferation was determined by 3-(4, 5-dimthyl-2-2thiazoly)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) colorimetry, and the expression levels of alpha smooth actin (alpha-SMA), collagen type I, and ERK were determined by Western blot. RESULTS: SAB and curcumin inhibited the proliferation and activation of rat's HSC-T6 in dose-dependent fashion and significantly reduced the expression level of alpha-SMA (P < 0.01). Curcumin significantly reduced the expression of collagen type I (P < 0.05). Both SAB and curcumin showed insignificant effect on the ERK expression level, but they could significantly reduce the level of phosphorylated-ERK expression, showing significant difference as compared with that in the control group (P < 0.01 and P < 0.05 respectively). CONCLUSION: SAB and curcumin could significantly inhibit the proliferation, activation of HSC, and the production of type I collagen in HSC, the mechanism may be associated with their inhibition on ERK phosphorylation.

Animals↗

PubMed2004

Antioxidant power of phytochemicals from Psidium guajava leaf.

Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin- Ciocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3 +/-15.5 and 511.6+/-6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH*) colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH* color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC(50) and the time needed to reach the steady state to EC(50) concentration (T(EC(50))) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used EC(50). This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.

Antioxidants↗

PubMed2005

Preparation of curcumin prodrugs and their in vitro anti-tumor activities.

The curcumin prodrugs, which could be selectively activated in tumor cells, were prepared to establish a basis for the targeted chemotherapy for cancer. On the basis of the molecular structure of curcumin, the N-maleoyl-L-valine-curcumin (NVC), N-maleoyl- glycine-curcumin (NGC) were chemically synthesized and identified by IR and NMR spectroscopy. After treatment with these two prodrugs for 6 - 24 h, the rates of growth inhibition on human bladder cancer EJ cells and renal tubular epithelial (HKC) cells were detected by MTT colorimetry. Our results showed that after the treatment with 20 micromol/L - 40 micromol/L NVC and NGC for 6 - 24 h, the growth inhibitory effects on EJ cells were 6.71% - 65.13% (P < 0.05), 10.96% - 73.01% (P < 0.05), respectively, in both dose- and time-dependent manners. When compared with the curcumin of same concentrations, the growth inhibitory effects of these two prodrugs on HKC cells were significantly decreased (P < 0.01). It is concluded that activation of curcumin prodrugs via hydrolysis functions of cellular esterase could inhibit the growth activities of tumor cells, and reduce the side effects on normal diploid cells. This provided a novel strategy for further exploration of tumor-targeted chemotherapeutic drugs.

Antineoplastic Agents, Phytogenic↗

PubMed2002

Chemo-radionuclide therapy for thyroid cancer: initial experimental study with cultured cells.

UNLABELLED: Radioiodine therapy has long been used for distant metastases of thyroid cancer. Although partially effective in most cases, it can render a complete cure only in a limited number of patients. One way to enhance its efficacy would be to combine it with antineoplastic agents. Here we describe an initial in vitro evaluation with 4 thyroid cancer cell lines. METHODS: Cells were sparsely seeded in microtiter plates and allowed to grow for 2 days; then they were exposed to sublethal concentrations of cisplatin (CDDP), doxorubicin (Dox), or 5-fluorouracil (5-FU), followed by treatment with I-131 for 48 hr. Cell survival was measured with a commercial kit based on the colorimetry of succinate dehydrogenase activity. RESULTS: Chemotherapeutic drugs exerted similar concentration-dependent cytotoxic effects in all 4 cell lines. The doses necessary to reduce the surviving fraction to half of the control were about 3 microg/ml for CDDP, 0.3 microg/ml for Dox, and 3 microg/ml for 5-FU (when used continuously for 48 hours). On the other hand, sensitivity to I-131 irradiation differed among the lines; same doses (7.4-14.8 MBq/ml) caused the greatest damage in FRO cells, a modest effect in NPA and WRO, and only minimal change in B-CPAP. The combined effect was most demonstrable in wells treated with Dox and radioiodine, whereas the addition of CDDP or 5-FU had marginal or insignificant merit, respectively. In FRO cells, half-lethal doses of the above mentioned CDDP, Dox, and 5-FU, when used together with 14.8 MBq/ml I-131, reduced cell survival to 54.5%, 29.4% and 33.4%, respectively, vs. 60.2% with radioiodine alone. CONCLUSION: In vitro, clinical concentrations of Dox can accelerate the killing of thyroid cancer cells by radioiodine. These favorable experimental results warrant future studies to evaluate whether this new bidisciplinary approach is clinically relevant and feasible.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1991

Minor and trace elements in human milk from Guatemala, Hungary, Nigeria, Philippines, Sweden, and Zaire. Results from a WHO/IAEA joint project.

Concentrations of As, Ca, Cd, Cl, Co, Cr, Cu, F, Fe, Hg, I, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Sn, V, and Zn were determined in human whole milk samples from Guatemala, Hungary, Nigeria, Philippines, Sweden, and Zaire; in most of these countries, three groups of subjects representing different socioeconomic conditions were studied. Analytical quality control was a primary consideration throughout. The analytical techniques used were atomic absorption spectrophotometry, atomic emission spectrometry with an inductively coupled plasma, colorimetry, electrochemistry, using an ion-selective electrode and neutron activation analysis. The differences between median concentrations of Ca, Cl, Mg, K, Na, and P (minor elements) were lower than 20% among the six countries. Among trace elements, concentrations observed in Filipino milk for As, Cd, Co, Cr, Cu, F, Fe, Mn, Mo, Ni, Pb, Sb, Se, and V were higher than for milk samples from other countries. The remaining five countries showed a mixed picture of high and low values. In the case of at least some elements, such as, F, I, Hg, Mn, Pb, and Se, the environment appears to play a major role in determining their concentrations in human milk. The nutritional status of the mother, as reflected by her socioeconomic status, does not appear to influence significantly the breast milk concentrations of minor and trace elements. Significant differences exist between the actual daily intakes observed in this study and current dietary recommendations made by, for example, WHO and the US National Academy of Sciences. These differences are particularly large (an order of magnitude or more!) for Cr, F, Fe, Mn, and Mo; for other elements, such as, Ca, Cu, Mg, P, and Zn, they amount to at least a factor 2. In the opinion of the present authors, these findings point to the need for a possible reassessment of the dietary requirements of young infants with respect to minor and trace elements, particularly for the elements Ca, Cr, Cu, F, Fe, Mg, Mn, Mo, P, and Zn.

Democratic Republic of the Congo↗

PubMedDate not supplied

Influence of obesity on sulfonamide disposition in Zucker rats.

The genetically obese Zucker rat was used as a model of obesity and compared to its lean littermate to assess and quantify obesity-altered changes in the in vivo disposition of six sulfonamides. Body composition determination indicated that the obese rats were twice the weight of lean rats and a distinct trend towards an increase in fat free mass and total body water was observed. The sulfonamide blood concentration was measured by colorimetry after a 7 mg/kg intravenous dose. All sulfonamides exhibited a biexponential decline of blood concentration with time. The volume of distribution and clearance of sulfanilamide in lean and obese rats were similar resulting in similar elimination half-lives. A decrease in clearance coupled with a trend towards an increase in volume of distribution prolonged the elimination half-life of sulfadiazine in obese rats. For sulfapyridine, sulfamerazine, sulfisomidine and sulfisoxazole, increases in the volumes of distribution and clearances resulted in similar elimination half-lives in lean and obese rats. The free fractions of the sulfonamides were significantly increased in the serum of obese rats, the influence of which on the volume of distribution and clearance is discussed.

Animals↗