Trends and predictions of metabolic risk factors for acute myocardial infarction: findings from a multiethnic nationwide cohort

Background

Understanding the trajectories of metabolic risk factors for acute myocardial infarction (AMI) is necessary for healthcare policymaking. We estimated future projections of the incidence of metabolic diseases in a multi-ethnic population with AMI.

Methods

The incidence and mortality contributed by metabolic risk factors in the population with AMI (diabetes mellitus [T2DM], hypertension, hyperlipidemia, overweight/obesity, active/previous smokers) were projected up to year 2050, using linear and Poisson regression models based on the Singapore Myocardial Infarction Registry from 2007 to 2018. Forecast analysis was stratified based on age, sex and ethnicity.

Findings

From 2025 to 2050, the incidence of AMI is predicted to rise by 194.4% from 482 to 1418 per 100,000 population. The largest percentage increase in metabolic risk factors within the population with AMI is projected to be overweight/obesity (880.0% increase), followed by hypertension (248.7% increase), T2DM (215.7% increase), hyperlipidemia (205.0% increase), and active/previous smoking (164.8% increase). The number of AMI-related deaths is expected to increase by 294.7% in individuals with overweight/obesity, while mortality is predicted to decrease by 11.7% in hyperlipidemia, 29.9% in hypertension, 32.7% in T2DM and 49.6% in active/previous smokers, from 2025 to 2050. Compared with Chinese individuals, Indian and Malay individuals bear a disproportionate burden of overweight/obesity incidence and AMI-related mortality.

Interpretation

The incidence of AMI is projected to continue rising in the coming decades. Overweight/obesity will emerge as fastest-growing metabolic risk factor and the leading risk factor for AMI-related mortality.

Funding

This research was supported by the NUHS Seed Fund (NUHSRO/2022/058/RO5+6/Seed-Mar/03) and National Medical Research Council Research Training Fellowship (MOH-001131). The SMIR is a national, ministry-funded registry run by the National Registry of Diseases Office and funded by the Ministry of Health, Singapore.

Rising incidence of thyroid cancer in Singapore not solely due to micropapillary subtype

Introduction The annual incidence of thyroid cancer is known to vary with geographic area, age and gender. The increasing incidence of thyroid cancer has been attributed to increase in detection of micropapillary subtype, among other factors. The aim of the study was to investigate time trends in the incidence of thyroid cancer in Singapore, an iodine-sufficient area. Materials and methods Data retrieved from the Singapore National Cancer Registry on all thyroid cancers that were diagnosed from 1974 to 2013 were reviewed. We studied the time trends of thyroid cancer based on gender, race, pathology and treatment modalities where available. Results The age-standardised incidence rate of thyroid cancer increased to 5.6/100,000 in 2013 from 2.5/100,000 in 1974. Thyroid cancer appeared to be more common in women, with a higher incidence in Chinese and Malays compared with Indians. Papillary carcinoma is the most common subtype. The percentage of papillary microcarcinoma has remained relatively stable at around 38% of all papillary cancers between 2007 and 2013. Although the incidence of thyroid cancer has increased since 1974, the mortality rate has remained stable. Conclusion This trend of increase in incidence of thyroid cancer in Singapore compares with other published series; however, the rise seen was not solely due to micropapillary type. Thyroid cancer was also more common in Chinese and Malays compared with Indians for reasons that needs to be studied further.

Ileocolorectal intussusception due to caecal hamartoma

Although 75% of intussusceptions occur within the first two years of life, they can also develop in teenage years. This is a case report of a 13-year old boy with an ileocolorectal intussusception from a large caecal hamartoma (10 x 6 x 2 cm3) adjacent to the ileocaecal valve. Partial resection of the ascending colon and terminal ileum was performed, and the pathology of the resected mass revealed a hamartoma. Ileocolorectal intussusception secondary to hamartoma represents a particularly rare event in the paediatric population. With early surgical intervention, this patient's outcome was uneventful.

Preparation of nano-sized particles from collagen II by a high-voltage electrostatic field system

The pilot study describes a novel method for preparing nano-sized particles from collagen II using a high-voltage electrostatic field system. Observations from transmission electron microscopy showed that, in one of the cases, the nano-sized collagen II particles exhibited good sphericity, and the particles were in the range of 23.3+/-1.7 nm in diameter at the experimental setting of 3 kV cm(-1), for a 3 h treatment period and at 25 degrees C (with a collagen concentration of 0.2 mg ml(-1)). When the treatment temperature increased to 30 degrees C, the collagen II began to lose the tendency to form individually separated spherically shaped nano-particles. Moreover, a fibrous structure of collagen II was formed instead of a nano-particle shape at the temperature of 37 degrees C. This result is probably contributed to by an entropy-driven process that is termed fibrillogenesis, a larger force causing the collagen molecules to self-assemble and then form collagen fibrils. It is interesting to note that this is practically the first attempt to produce nano-particles directly from collagen II solution under the treatment of a high-voltage electrostatic field, together with a set of working parameters for the collagen concentration and low-temperature setting.

Dihydropyridine calcium channel blockers inhibit ascorbic acid accumulation in human intestinal Caco-2 cells

We investigated the effect of commonly used medications on the accumulation of ascorbic acid in human intestinal Caco-2 cells. Although ascorbic acid is negatively charged at physiological pH, anionic compounds including drugs and metabolites had little effect on its accumulation. On the other hand, hydrophobic 1,4-dihydropyridine compounds (nifedipine and nicardipine), but not other structurally unrelated calcium channel blockers, were found to be potent inhibitors. They inhibited both Na+-dependent and Na+-independent (K+ substituting Na+) accumulation of ascorbic acid. The inhibition was non-competitive with a Ki of 108 microM and 9 microM for nifedipine and nicardipine, respectively. The efflux of ascorbic acid from cells was not affected. Previously, we reported a similar inhibition of ascorbic acid accumulation by estrogens. When nifedipine and estrogens were included in the buffer together, the combined inhibitory effect was less than additive implying that they may act through the same mechanism. The potential clinical significance of dihydropyridine usage on ascorbic acid status in human needs to be considered.

Quercetin cumulatively enhances copper induction of metallothionein in intestinal cells

Wilson's disease, a genetic copper-overload condition, is currently treated with zinc because of the ability of zinc to induce metallothionein. We are interested in nonmetal chemicals that may alter intestinal copper metabolism and thus help to alleviate copper toxicity. Previously, we have shown that quercetin, a dietary flavonoid, can chelate copper. This study further examined the interaction of quercetin and copper in intestinal epithelial cells. We found that quercetin enhanced metallothoinein induction by copper and the effect was dose dependent. Quercetin also exerted a cumulative effect after repeated exposure. Repeated low-dose treatment (3-10 microM) of cells with quercetin can lead to the same effect on metallothoinein as one higher concentration treatment (100 microM). This property of quercetin is distinct from its chemical interaction with copper, but both can contribute to a reduction of copper toxicity. Among other flavonoids tested, two other copper chelators, catechin and rutin, did not increase copper induction of metallothionein, whereas genistein, an isoflavone that does not interact with copper chemically, increased copper induction of metallothionein. The effect of quercetin on copper metabolism is unique. Quercetin decreased zinc-stimulated metallothionein expression and had no effect on the cadmium induction of metallothionein. The clinical application of our observation needs to be explored.

Determination of 14 elements in Taiwanese bones

The objective of this study was to measure the concentration of 14 elements in human bone and investigate the affecting factors. This study aims to establish a database of elements in Taiwanese bone. Seventy-seven bone samples were taken from 70 subjects who were undertaking various bone surgeries from a medical center in central Taiwan. Bone samples were pretreated using microwave digestion and then, after determining the optimal conditions for analysis, fourteen elements were analyzed using Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). Results showed that Ca had the highest concentration, followed by Mg and Zn. The lowest concentrations were of Mn, followed by Cd and Co. There was a positive correlation between the frequency of seafood intake and presence of all the 14 elements in human bone. There were several elements that had positive inter-correlation: As with Co; Al, Ag and Ca; Ni with Co, Mn and Al; Co with Al, Ag and Ca; Mn with Cr and Cu; Cr with Cu; Mg with Ca; Al with Ag and Ca; Ag with Ca; and also Zn with Mg. There were no significant differences found between concentrations of elements and etiology of bone disease and age. The authors suggest that further studies be conducted to establish a normal value of elements in human bone in Taiwan. This will greatly benefit the understanding of the relationship between disease pattern and elements in human bone.

Expression of antioxidant proteins in human intestinal Caco-2 cells treated with dietary flavonoids

Dietary flavonoids are known to scavenge free radicals but little information is available on their roles in antioxidant protein gene expression. The goal of this paper is to investigate the effect of flavonoid treatment on the antioxidant protein expression in human intestinal Caco-2 cells. The antioxidant proteins of interest were metallothionein (MT), catalase (CAT), and superoxide dismutase (SOD). Treatment of Caco-2 cells with 100 microM genistein, biochanin A, daidzein or kaempferol significantly increased MT mRNA up to 15 fold. On the contrary, CAT mRNA level was not affected by various flavonoids. We also developed gel activity assays to determine the specific activities of CAT and Cu/Zn SOD in flavonoid-treated Caco-2 cells. Compared to the conventional spectrophotometric assays, the gel assays allow a separation of antioxidant activities of the enzymes from that of the flavonoids. CAT and Cu/Zn SOD were found not to be affected by 48-h treatment of 100 microM dietary flavonoids (genistein, biochanin A, daidzein, flavone, quercetin, or kaempferol). In conclusion, the effects of flavonoids on antioxidant protein expression are structure- and gene-specific. When evaluating antioxidant capacity of flavonoids, their ability to modulate antioxidant protein expression should also be taken into consideration.

Genistein increases metallothionein expression in human intestinal cells, Caco-2

Flavonoids found in common vegetables, fruits, and legumes have been shown to possess antioxidant property. This study is the first to demonstrate that one member of the flavonoid family, genistein, can induce the expression of metallothionein (a metal-binding protein with antioxidant property). We found the effect of genistein to be time- and dose-dependent (10-100 microM). The effect can be observed at both protein and mRNA levels and was synergistic to that of 30 microM zinc. Genistein was shown previously to interact with the estrogen receptor and induce gene expression similar to estrogens at a lower affinity. We thus tested the hypothesis that the effect of genistein on metallothionein expression was mediated through the steroid hormone pathway. We found that various glucocorticoids do not affect metallothionein expression in Caco-2 cells. 17Beta-estradiol at 10-100 microM (concentrations much higher than needed to activate the estrogen response element) induced metallothionein expression in Caco-2 cells. However, a synthetic estrogen, diethylstilbestrol, did not increase metallothionein level at 10 microM. 17Beta-estradiol also did not act synergistically with zinc. Thus, genistein may enhance metallothionein expression through an uncharacterized mechanism. Further studies are needed to delineate the molecular mechanism and to determine whether the expression of other genes is also affected by genistein.

Amination of polycarbonate surface and its application for cell attachment

The polycarbonate sheet was modified with ammonia gaseous plasma and characterized by the contact angle measurement and ESCA analysis. The contact angles decreased significantly from 77 degrees to about 20 degrees-40 degrees, indicate that the polycarbonate sheet become more hydrophilic after plasma treatment. The ESCA analysis results showed that the hydrophilicity was mainly derived from the amino groups on the modified surface. In this study, a flow-chamber system was also constructed to evaluate the 3T3 fibroblast cells attachment phenomena on these modified sheets. Before the experimental run, the parameters of inoculated cell number and cell passage were examined previously. The results revealed that these two parameters are independent in shear experiment. And besides, 3-hours plating time has the better adhering fraction. The experimental results showed that the 3T3 fibroblast cells adhesion strength increased significantly on the plasma modified sheet.

Transepithelial transport and accumulation of flavone in human intestinal Caco-2 cells

Flavonoids are found in many food items of plant origin. Intake of flavonoids has been linked to the prevention of human diseases including cancer. However, little is known about the intestinal absorption of flavonoids in the cellular level. This study was designed to study the absorption of dietary flavonoids using cultured human intestinal epithelial cell monolayer as a model system and 14C-flavone as a model compound. 14C-flavone at 10 microM was found to move across the cell monolayer rapidly both from the luminal to basolateral direction and from the basolateral to luminal direction. The rate of transport from the luminal to basolateral direction was 5 times of the rate for phenylalanine, an aromatic amino acid. Flavone also accumulated substantially in the cells. Replacing sodium in the transport buffer with potassium did not affect the transport but reducing the incubation temperature significantly decreased the initial rate of transport. The presence of protein in the transport buffer reduced the initial rate of transport to half. Other flavonoids and hydrophobic chemicals at 100 microM had no effects on the transport. Together with the evidence from microscopic observation (Cancer Letts. 110: 41-48, 1996), this study supports that rapid diffusional transport may be the main route for flavonoid absorption. The ability of intestinal cells to accumulate flavone is consistent with the role of flavonoids in colon cancer prevention.

17beta-estradiol inhibition of ascorbic acid accumulation in human intestinal Caco-2 cells

We investigated the effect of estrogen on the accumulation of ascorbic acid by human intestinal Caco-2 cells. 17beta-estradiol, synthetic estrogen diethylstilbestrol, and partial agonist tamoxifen were found to inhibit ascorbic acid accumulation in a dose-dependent fashion. The inhibitory effect of estrogens can be observed at as short as 5 min of incubation. An additive effect was observed when they were used in combination. Similar to dietary flavonoids, inhibition was also observed in two other intestinal cell lines, HT-29 and IEC-6. These chemicals affected both Na+ -dependent and Na+ -independent(K+ substituting Na+) accumulation of ascorbic acid and did not affect the efflux of accumulated ascorbic acid. Kinetic analysis of diethylstilbestrol showed a non-competitive inhibition with an apparent Ki of 23 microM. The hormone-ascorbic acid interaction in the intestinal cell could help to explain the known reduction in blood ascorbic acid level among oral contraceptive users and female guinea pigs given contraceptive hormones.

Dietary flavonoids interact with trace metals and affect metallothionein level in human intestinal cells

Flavonoids are natural compounds found in food items of plant origin. The study examined systematically the interaction of structurally diverse dietary flavonoids with trace metal ions and the potential impact of dietary flavonoids on the function of intestinal cells. Spectrum analysis was first performed to determine flavonoid-metal interaction in the buffer. Among the flavonoids tested, genistein, biochanin-A, naringin, and naringenin did not interact with any metal ions tested. Members of the flavonol family, quercetin, rutin, kaempferol, flavanol, and catechin, were found to interact with Cu(II) and Fe(III). On prolonged exposure, quercetin also interacted with Mn(II). Quercetin at 1:1 ratio to Cu(II) completely blocked the Cu-dependent color formation from hematoxylin. When quercetin was added to the growth medium of cultured human intestinal cells, Caco-2, the level of metal binding antioxidant protein, metallothionein, decreased. The effect of quercetin on metallothionein was dose- and time-dependent. Genistein and biochanin A, on the contrary, increased the level of metallothionein. The interaction between dietary flavonoids and trace minerals and the effect of flavonoids on metallothionein level imply that flavonoids may affect metal homeostasis and cellular oxidative status in a structure-specific fashion.

The protein thiol metallothionein as an antioxidant and protectant against antineoplastic drugs

Metallothioneins (MTs) are major zinc-binding protein thiols that are readily inducible and whose functions remain unclear. Recent evidence supports a role for MT as an antioxidant. Mechanisms underlying this function may include direct interception of free radicals, complexation of redox sensitive transition metals, altered zinc homeostasis or interaction with glutathione (GSH). MT overexpression after direct gene transfer in cultured cells, decreases cytotoxicity, to partially reduce reactive oxygen and nitrogen species and markedly attenuates intracellular oxidation of reporter molecules including dichlorofluorescein and cis-parinaric acid. Conversely, enhanced intracellular oxidation is seen in cells derived from mice lacking both functional MTI and MTII genes. GSH levels are unaffected in MT null cells relative to wildtype, suggesting the antioxidant function of MT is independent of GSH. In tumor cells there is at least a 400-fold range in MT levels and a 10-fold difference in the ratio of nuclear to cytoplasmic distribution. No correlation exists between MT levels and GSH levels demonstrating the autonomous regulation of intracellular thiol pools. This may be important for cancer chemotherapies since MT overexpression is seen in human tumor cells with acquired drug resistance. The authors found no evidence for altered MT isoform profiles in drug resistant cells that overexpress MT. Recent evidence suggests MT subcellular location may dictate functionality and MT may help determine the threshold for apoptosis. Thus, MT is a stress-inducible protein with antioxidant attributes that may participate independently or in conjunction with GSH to protect cells against injurious agents.

Dietary flavonoid and cancer prevention: evidence and potential mechanism

Dietary flavonoids represent a family of polyphenol compounds found in common food items derived from plants. Depending on structural features, flavonoids can be further subdivided into flavones, flavonols, isoflavones, flavanes, and flavanols. The biological activities of flavonoids are structure dependent and epidemiological studies support their role in human cancer prevention. Several flavonoids inhibit cancer development in animal models of chemical and UV carcinogenesis. However, at high dose some flavonoids themselves may also increase cancer incidence. Although flavonoids have been shown to inhibit cancer cell growth in vitro, the ability of flavonoids to limit cancer progression is limited in animal studies. A potential application is the possible synergisticaction of flavonoids with chemotherapy agents. Molecularly, flavonoids have antioxidant properties and can further enhance the antioxidant protein activities in cells and in animals. Isoflavones and some other flavonoids have weak affinity for the estrogen receptor. Neonatal exposure of animals to isoflavonoids affects the development of reproductive organs, an observation that opens the possibility of using isoflavonoids in the prevention of cancers of the reproductive system. Some growth-inhibiting flavonoids also bind to the low-affinity type II estrogen binding sites, but the biochemical identity of type II sites is unknown.

Plasma-modified nylon meshes as supports for cell culturing

The polymeric surfaces of three commercially available nylon films with mesh openings of 5 microns, 10 microns and 20 microns were treated with anhydrous ammonia gaseous plasma. Cells cultured on the plasma-treated nylon films have higher proliferation rate and assume morphology distinct from those cultured on the unmodified films. Of the three plasma-modified membranes, the one with 5 microns mesh openings supported a largest population of cell growth. The plasma-treated nylon meshes provided a stronger anchorage for the collagen matrices formed within the mesh openings. Application of this collagen/nylon meshes for cell culturing is demonstrated.

Effect of antiproliferative flavonoids on ascorbic acid accumulation in human colon adenocarcinoma cells

Dietary flavonoids were found to be antiproliferative for human colon cancer cells, Caco-2 and HT-29, and rat nontransformed intestinal crypt cells, IEC-6. The antiproliferative potency was found to be structure-dependent. We report here a correlation between the antiproliferative potency of these flavonoids and their ability to inhibit cellular accumulation of ascorbic acid (vitamin C). Caco-2, HT-29 and IEC-6 cells were found to accumulate ascorbic acid in a sodium-dependent fashion although some ascorbic acid may also enter the cells through sodium-independent mechanisms. Flavonoids that have been found to be antiproliferative, quercetin and genistein, inhibited the accumulation of ascorbic acid. The inhibition was dose-dependent and could be observed after as short as 10-min of incubation. The degree of inhibition of accumulation was more during rapid cell division as compared to post-confluency Caco-2 cells. Flavonoids that were found to show little antiproliferative effect, naringenin and catechin, also had little effect on ascorbic acid accumulation. The antiproliferative property of flavonoids could be linked to their ascorbic acid deprivation property.

Effect of PVA-AA on dentine bonding of HEMA

PVA-AA, an esterification product of poly(vinyl alcohol) and acryloyl chloride, was synthesized and tested for its dentine bonding ability as an additive to 2-hydroxyethyl methacrylate (HEMA). The dentine bonding strength increased significantly by increasing the concentration of PVA-AA in HEMA. The dentine tensile bonding strength attained by the mixture of 10 wt% PVA-AA in HEMA is about 38% higher than that of HEMA or Gluma bonding agent. The dentine shear bonding strength also increased by increasing the acrylate content of the PVA-AA up to about 30%. Test results of cell culturing indicate that no toxic substance is released from PVA-AA to inhibit the cell growth.

Antiproliferative potency of structurally distinct dietary flavonoids on human colon cancer cells

Dietary flavonoids are known to be antiproliferative and may play an important role in cancer chemoprevention, especially cancers of the gastrointestinal tract, because of a direct contact with food. This study was designed to compare the antiproliferative potency of several structurally distinct dietary flavonoids in colon cancer cells, Caco-2 and HT-29, and in rat non-transformed intestinal crypt cells, IEC-6. Flavonoids varied significantly in their antiproliferative potency depending on the structural features but the observations were consistent among the three cell lines studied. Of the two most potent flavonoids, quercetin and genistein, the effect was found to be dose-dependent and chromatin condensation, an indication of apoptosis, was noticed. Quercetin was found to distribute throughout the cell with higher amounts in the perinuclear and nucleoli areas. The lack of specific cell membrane enrichment by quercetin was consistent with its lack of effect on the transepithelial resistance. While several flavonoids including quercetin were found to be unstable, the chemical instability did not correlate with the antiproliferative potency, although it may contribute to the antiproliferative effect.

Pathways for oxalate transport in rabbit renal microvillus membrane vesicles

Recent evidence suggests that apical membrane Cl--oxalate exchange plays a major role in mediating Cl- absorption in the renal proximal tubule. To sustain steady-state Cl- absorption by a mechanism of exchange for intracellular oxalate requires the presence of one or more pathways for recycling oxalate from lumen to cell. Accordingly, we evaluated the mechanisms of oxalate transport in luminal membrane vesicles isolated from the rabbit renal cortex. We found that transport of oxalate by Na+ cotransport is negligible compared to the transport of sulfate. In contrast, we demonstrated that oxalate shares the electroneutral pathway mediating Na+-independent sulfate-carbonate exchange. We also demonstrated the presence of OH--oxalate exchange (indistinguishable from H+-oxalate cotransport). The process of OH--oxalate exchange was electrogenic and partially inhibited by Cl-, indicating that it occurs, at least in part, as a mode of the Cl--oxalate exchanger described previously. An additional component of OH--oxalate exchange was insensitive to inhibition by either Cl- or sulfate, suggesting that it takes place by neither the Cl--oxalate exchanger nor the sulfate-carbonate exchanger. We conclude that multiple anion exchange mechanisms exist by which oxalate can recycle from lumen to cell to sustain Cl- absorption occurring via apical membrane Cl--oxalate exchange in the renal proximal tubule.

Animal study of phoenix total artificial heart implantation

BACKGROUND

It is well accepted that a total artificial heart (TAH) can be used as a bridge to heart transplantation during the waiting period for organ donation. A series of combined studies, conducted by the Kaohsiung Veterans General Hospital, National Yang-Ming Medical College and Municipal Tainan Hospital, has been performed to improve the Phoenix artificial heart developed by Dr. Kevin Kuo-Tsai Cheng.

METHODS

In growing calves (weighed about 80 kg), standard procedures were used to remove the hearts and replace them with the TAHs. Records were made of hemodynamic data, physiological responses, blood biochemistry data and physical activities after operation and until the death of the calves. Finally, autopsies were used to determine the causes of death.

RESULTS

A total of 23 calves were studied. Twenty-two of them survived 1 to 12 days, or an average 4.95 days. One survived more than 30 days. All the calves could breathe, stand, eat and void by themselves two hours after operation. Respiratory failure was the major cause of death.

CONCLUSIONS

No thrombus within the TAH was noted in the last five cases, meaning that turbulent flow or dead space of the TAH was improved. Better intensive care and prevention of infection will be the next challenge for long-term use of TAH.

Metallothionein localization and cisplatin resistance in human hormone-independent prostatic tumor cell lines

Metallothioneins (MT) are major cysteine-rich proteins with poorly characterized functions. We have examined the MT amount, isotype expression, and subcellular distribution in 4 human hormone-independent prostatic carcinoma cell lines. Both PC-3 and DU-145 cells were thiol-rich cells with similar MT and glutathione levels, while HPC36M and PC-3 MA2 were thiol-poor cells with lower MT and glutathione levels. All 4 prostatic cell lines expressed the MTIIA isoform at a basal level; DU-145 cells also constitutively expressed MTIE mRNA. Using antibodies for both total MT and MTIIA, we defined MT to cytoplasmic and nuclear domains in PC-3 cells, to perinuclear and nuclear domains in HPC36M cells, and to prominent nonnucleolar nuclear domains in DU-145 and PC-3 MA2 cells. These results indicate that the subcellular distribution is cell type specific and not reflective of the total MT content or MT isoform. Resistance to cadmium in all 4 cell lines was correlated with total MT levels, while resistance to the anticancer agent cisplatin correlated best with nuclear MT content. We suggest that the subcellular localization of MT is functionally important in cellular protection against the anticancer agent cisplatin in human prostatic cancer cells.

Interleukin-1 beta-mediated metallothionein induction and cytoprotection against cadmium and cis-diamminedichloroplatinum

Metallothioneins (MTs) are major intracellular protein thiols that have been associated with resistance to the cytotoxicity of heavy metals and some cytotoxic anticancer drugs. The accumulation and subcellular location of MT and its functionality were examined in a human hormone-independent prostatic tumor cell line (DU-145) exposed to cytokines that participate in autocrine growth and the acute phase response. Incubation of DU-145 cells with interleukin-1 beta (IL-1 beta) caused a concentration-dependent increase in MT protein reaching a 2- to 3-fold maximum increase 24 to 48 hr after treatment with 10 U of IL-1 beta/ml; smaller increases were seen with human recombinant IL-1 alpha and tumor necrosis factor alpha. DU-145 cells constitutively expressed only MT-IIa and MT-Ie mRNA and the IL-1 beta-mediated increase in MT protein was preceded by a marked elevation solely in MT-IIa mRNA. Basal MT was immunolocalized by confocal microscopy primarily to the nucleus of DU-145 cells with some granular deposits near the cell surface. IL-1 beta treatment increased nuclear MT. DU-145 cells pretreated with IL-1 beta were 2- to 3-fold resistant to the toxicity of CdCl2 and cis-diamminedichloroplatinum(II) (cisplatin). Both MT induction and cytoprotection against CdCl2 and cisplatin were blocked by concomitant incubation with a recombinant human IL-1 receptor antagonist protein. These results suggest the responsiveness of human prostatic tumor cells to cytotoxic electrophilic anticancer drugs can be diminished by direct exposure to the cytokine IL-1 beta, possibly by a mechanism involving MT.

The contribution of intestinal secretion to the dose-dependent absorption of celiprolol

The contribution of the intestine to the nonlinear absorption of celiprolol in the rat was studied. After intravenous administration of 14C-celiprolol to bile duct-cannulated rats, approximately 9% of the dose was found to be associated with intestinal tissue and its contents. Microhistoautoradiography of frozen intestinal sections showed a time-dependent secretion of celiprolol from the blood into the lumen of the rat intestine. Propranolol, a lipophilic beta-blocker, was also found to be secreted into the intestine in vivo and transported in epithelial cells in both a temperature- and a pH-dependent manner, although to a lesser extent than celiprolol. Consistent with the observations in rats, transport of celiprolol from the basal-lateral to the apical side was found to dominate apical-to-basal transport using human Caco-2 cell monolayers. Additionally, using isolated rat small intestinal epithelial cells, celiprolol was found also to have a time- and temperature-dependent uptake, suggesting the involvement of a carrier-mediated system in its uptake. The uptake was inhibited by 2 mM celiprolol and propranolol and was also found to be pH dependent. Saturation of the carrier-mediated secretion of celiprolol in the intestine may result in enhanced absorption of celiprolol at high doses and account for its observed nonlinear absorption.

Subcellular localization of metallothionein IIA in human bladder tumor cells using a novel epitope-specific antiserum

Human metallothioneins (hMTs) are a family of highly homologous proteins thought to be critical in cellular protection against toxins. The comparative function of individual isoforms is, however, obscure. Antibodies to individual MT isoforms might help clarify this issue but their generation has been challenging. We now describe a strategy that has successfully produced an epitope-specific antiserum to a major human isoform, hMT IIA. The immunogen, a conjugated tridecyl amino acid synthetic peptide unique to residues 8-20 in hMT IIA (AAGDSCTCAGSCK), yielded an antiserum (B2) that reacted specifically with hMT IIA in a concentration- and titer-dependent manner and showed no reactivity with human or rabbit liver MT I or horse MTs. This antiserum recognized rabbit liver MT II and, surprisingly, also reacted weakly with chicken MT. MT amino acid sequence comparisons and peptide blocking studies suggested aspartate-11 and threonine-14 are important antigenic determinants for B2. Using confocal immunofluorescence microscopy and B2 antiserum, we observed nuclear localization of hMT IIA with human bladder T24 tumor cells in exponential growth but more cytoplasmic localization at confluence. These results suggest the subcellular location of hMT IIA is a function of cell density in T24 bladder carcinoma cells. The general approach of epitope-specific antibodies may be useful for the generation of antibodies to other MT isoforms and for studying the role of individual MT isoforms in biology and toxicology.

Transport of celiprolol across human intestinal epithelial (Caco-2) cells: mediation of secretion by multiple transporters including P-glycoprotein

1. The transepithelial transport of the beta-adrenoceptor blocking drug, celiprolol, was investigated in monolayers of the well differentiated human intestinal epithelial cell line, Caco-2. 2. The basal-to-apical transport (secretion) of [14C]-celiprolol (50 microM) was 5 times higher than apical-to-basal transport (absorption). In the presence of an excess (5 mM) of unlabelled celiprolol the basal-to-apical transport was reduced by more than 80%, whereas the apical-to-basal transport remained unchanged. 3. Net celiprolol secretion obtained in the concentration range 0.01 to 5 mM displayed saturable kinetics with an apparent Km of 1.00 +/- 0.23 mM and Vmax of 113 +/- 11 pmol/10(6) cells min-1. These results are consistent with saturable active secretion and provide an explanation for the dose-dependent bioavailability of celiprolol. 4. The secretion of celiprolol was sensitive to pH, and decreased in the absence of sodium and in the presence of ouabain, suggesting that transport was coupled to proton and sodium gradients. 5. The secretion of celiprolol was inhibited by substrates for P-glycoprotein (vinblastine, verapamil and nifedipine) and either inhibited or stimulated by typical substrates for the renal organic cation-H+ exchanger (cimetidine, N1-methylnicotinamide, tetraethylammonium and choline), suggesting that there are at least two distinct transport systems. 6. The secretion of celiprolol was also inhibited by other beta-adrenoceptor blocking drugs (acebutolol, atenolol, metoprolol, pafenolol and propranolol) and by the diuretics, acetazolamide, chlorthalidone and hydrochlorothiazide, suggesting that the clinically observed effect of chlorthalidone on the bioavailability of celiprolol occurs at the level of the intestinal epithelium.

The use of transesophageal echocardiography to evaluate the effectiveness of patent ductus arteriosus ligation

The ligation of patent ductus arteriosus (PDA) is a comparatively easy operation, but some complications are possible. The most common complication is incomplete ligation of the PDA; others include inadvertent ligation of the descending aorta or left pulmonary artery, transient rise in systemic blood pressure and increased left ventricular afterload, and acute right heart failure due to pulmonary hypertension. The completeness of the PDA ligation is usually determined only by the operating physician's experience, including the use of an esophageal stethoscope or a finger on the lesion to feel for vibration. These methods sometimes fail to detect an incomplete ligation. With transesophageal echocardiography (TEE), we have monitored the entire course of the PDA ligation directly without interrupting the surgical procedure, and precisely determined the completeness of the ligation. We also expect that TEE will enable us to avoid other complications as well.

Expression of pulmonary metallothionein genes in late gestational lambs

Metallothioneins (MT) are low molecular weight proteins that are important in providing protection against heavy metals such as cadmium. Other precise physiologic roles for this family of proteins are less clear, but fetal hepatic cell proliferation and differentiation may be regulated through changes in MT levels and attendant MT-mediated regulation of zinc levels. The role of MT in other developing tissue, most notably lung, is far less clear. Although expression of MT has been reported to be extremely low in early postnatal and mature lung, we hypothesized that MT has a more ubiquitous role in organ development and that pulmonary MT levels may be elevated during periods of rapid lung growth. Thus, we studied expression of MT in late-gestation fetal lambs. Sheep are particularly useful because alveolarization of lung parenchyma occurs before birth (by d 120 of a normal 147-d gestation). Immunoreactive MT was localized to bronchial epithelium of fetal, newborn, and mature sheep. The intensity of staining was greatest in the 130-d gestational age (saccular) lung, where positive reaction product was noted in the cytoplasm and nucleus of alveolar epithelial and interstitial cells. We next evaluated MT expression in developing lung tissue using Northern blot analysis and 32P-cDNA probes against the 3'-untranslated regions of mRNA encoding each of four known functional sheep MT (sMT) isoforms. Expression of sMT-II, sMT-Ia, and sMT-Ib was restricted to the saccular stage (120-132 d gestational age), and sMT-Ic mRNA was not detected in pulmonary samples from any stage of development.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical repair of ventricular septal defect without ventriculotomy in the first 12 months of life

Sixty-eight infants with clinical evidence of a large ventricular septal defect (VSD), refractory to conventional medical treatment, underwent surgical closure within the first 12 months of life from August 1987 to June 1991. There were 43 males and 25 females. The ages of the patients ranged from two to 12 months, with a mean age of 6.6 months. The mean body weight of the patients was 5.4 kg (range, 2.3-10 kg). Surgery was performed because of intractable heart failure in 27 infants (39.7%), failure to thrive in 40 (58.8%), repeated pneumonia in 43 (63.2%) and prolonged endotracheal intubation in nine (13.2%). There were 21 patients with a supracristal VSD (30.9%) and 47 patients with perimembranous VSD (69.1%). Nine patients (13.2%) had preoperative cardiac catheterization. Transatrial repair of perimembranous VSDs and transpulmonary repair of supracristal VSDs was used exclusively without ventriculotomy. Surgically induced heart blocks did not occur in any of the patients. Only two patients (2.9%) died during the early postoperative period. Diagnosis in most cases was confirmed by the present advanced integrated color Doppler echocardiographic technology which is widely used by pediatric cardiologists. There was no need to perform cardiac catheterization in most patients with VSDs. The morbidity and mortality were very low. We strongly suggest that for infants with a large VSD, primary repair should be the procedure of choice.

Initial results of laser angioplasty under angioscopic guidance for salvage of an ischemic lower limb: preliminary report

From March to July 1989, nine patients at risk for peripheral artery disease underwent intraoperative Nd:YAG laser angioplasty using angioscopy at the Veterans General Hospital (Taipei, Taiwan, Republic of China). Following the laser angioplasty, balloon dilatation was performed in all cases. Eight men and one woman at an average age of 68 were included in the study (range: 58 to 78 years old). Ischemic symptoms included five patients with disabling claudication, four with pain at rest and one with gangrene on the toes. Eight of the nine patients had complete occlusions ranging from 2 to 19 cm in length. Two patients had high degree multiple segmental stenosis of the superficial femoral artery from 1 to 2 cm in length. Initial clinical success (indicated by relief of symptoms and increase in Doppler ankle pressure and index) and improvement in the angiographic luminal diameter was noted in 9 of 10 occluded vessels (90%) that underwent Nd:YAG laser treatment which was delivered at 10 to 12 watts through laser probes. Prelaser intraluminal diameter increased from 0.05 +/- 0.07 to 0.53 +/- 0.07 mm, Doppler ankle pressure index rose from 0.51 +/- 0.12 to 0.81 +/- 0.12, Doppler ankle pressure increased from 62.44 +/- 16.10 to 104 +/- 21.21 mmHg and the amplitude of pulse volume recorder at ankle level rose from 5.77 +/- 2.80 to 12.11 +/- 2.77 mm as compared with prelaser therapy (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Transatrial-transpulmonary repair of tetralogy of Fallot: extensive infundibular septum resection

Twenty-seven patients with tetralogy of Fallot underwent total correction during the period from February 1988 through October 1989. Their ages ranged from 11 months to 12 years (mean 3.3 +/- 4.9 years). For 11 patients, the repair was made via the conventional transventricular approach and a partial resection of the infundibular septum. On the other 16 patients, a transatrial-transpulmonary approach was used with total resection of the anterior deviated infundibular septum, with or without a miniventriculotomy incision (1-10 mm). The exposure of the ventricular septal defect (VSD) through the right atrium, and the right ventricular outflow tract (RVOT) through the pulmonary artery in patients with tetralogy of Fallot was excellent. There were no significant differences between transatrial-transpulmonary repair and transventricular repair of the tetralogy of Fallot with respect to pulmonary artery (PA) index (273.2 +/- 36.6 versus 249.9 +/- 63.2 mm2/BSA) or the postoperative ratio of right ventricle/left ventricle (RV/LV) systolic pressure (0.55 +/- 0.16 versus 0.61 +/- 0.17). Postoperative intensive care was simple and uncomplicated, with a significantly lower catecholamine demand, less bleeding, fewer blood transfusions, and shorter stays in the cardiac Intensive Care Unit (ICU). There was no mortality in this series. This method of repair can be successfully accomplished in most patients with tetralogy of Fallot, with resultant preservation of right ventricular function (intact right ventricle).

Assessment of ventricular septal defect by echocardiography

Both 2-D echocardiography and angiocardiography were performed preoperatively in 40 children with isolated ventricular septal defect (VSD). The diagnosis of VSD was confirmed and the size of VSD was measured during operation within on month of the study. There were 27 males and 13 females (age: 10mos-9 yrs). The VSD was classified into perimembranous type (24), supracristal type (14), and AV canal type (2) by surgery. The maximal VSD areas were calculated by 1/4 pi De2 (De = maximal defect diameter measured by 2D echo). The maximal shunt flow areas were measured by color Doppler echocardiography from frame by frame search of the video tape. The maximal shunt flow area was corrected by the body surface area to be the maximal shunt flow area index. A left ventriculogram (LVG) was performed from 4-chamber and left lateral views to measure the maximal diameter of the defect. The maximal defect area of VSD on angiocardiogram was also calculated by 1/4 pi Da2 (Da = maximal defect diameter measured by angiocardiography). The VSD areas measured by different methods were compared by the linear regression analysis. We found that: (1) there is good correlation of the maximal defect diameter and the area of ventricular septal defect by 2-DE and LVG (r = 0.80, p less than 0.0001 v.s. r = 0.78, p less than 0.0001). (2) the ventricular septal defect area by 2-DE had a better correlation with the surgical measurement than that by LVG (r = 0.93, p less than 0.0001, v.s. r = 0.80, p less than 0.0001). (3) the size of ventricular septal defect measured by two-dimensional echocardiography has a better correlation with the MSFAI than the LVG did (r = 0.81, p less than 0.0001, v.s. r = 0.64, p less than 0.0001). Therefore, by measuring the maximal defect diameter, maximal defect area and maximal shunt flow area index, the echocardiography can provide an accurate and non-invasive assessment of isolated VSD in children.

[Results of vascular reconstruction in lower limbs ischemia: a six-year clinical experience]

During the period between Dec. 1982 to Nov. 1988, a total of 412 patients with 471 limbs at risk of peripheral arterial occlusive disease underwent vascular surgical treatment at the Veterans General Hospital. There were 382 men and 30 women, who ranged in age from 20 to 84 years (mean 63.17 +/- 11.85 years). 95 cases were isolated aortoiliac occlusive disease, 94 cases were combined aortoiliac and femoropopliteal disease, 169 cases were femoropopliteal occlusive disease and 54 cases were femorotibialperoneal occlusive disease. Various reconstructive procedures were performed in the these patients. The cumulative limb salvage rate (LSR) exceeded cumulative patency rate (CPR) in all categories and the result of LSR and CPR were 97.6% and 91% for aortoiliac reconstructive surgery in six years, 96% and 77% for above-knee femoropopliteal saphenous vein bypass (SVB) in six years, 79% and 74% for below-knee femoropopliteal SBV and 63% and 34% for femoro-distal SVB in five years. 88% and 76% for above-knee femoropopliteal human umbilical vein (HUV) bypass in four years. 67% and 45% for femoro-distal HUV bypass in three years follow-up period individually. The immediate good symptomatic results of the vascular reconstruction was 88% encountered in isolated aortoiliac disease, 63% in combined aortoiliac and femoropopliteal disease, 70.4% in isolated femoropopliteal disease and only 26% in femorotibial-peroneal disease (FTP). No change symptoms was still higher (33%) in FTP than the other vascular reconstruction due to poor distal runoff in this series. The early postoperative mortality rate was 1.6%, the late mortality rate was 2.7%, the incidence of postoperative complication rate was 13.6%. The major lower limb amputation rate was low as 7% in our series.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental implantation of human umbilical vein grafts in dogs

Locally produced human umbilical vein grafts (HUVG), using glutaraldehyde as a stabilizing agent, were implanted into 24 mongrel dogs. Different arterial bypass procedures, using HUVG, were carried out in three experimental groups. In Group I, 2 dogs underwent femorofemoral crossover bypass procedures and 6 dogs received aortoiliac bypass procedures. Thrombus formation was found in all HUVG implants of Group I. In Group II, 8 dogs received abdominal aorta HUVG interposition. In Group III, 8 dogs received abdominal aorta HUVG bypass procedures. Patent HUVG implants without thrombus formation, demonstrated by postoperative angiogram, were found in 6 dogs of Group II and 5 dogs of Group III. Morphological and histological studies of the patent HUVG implants retrieved after sacrifice showed on sign of rejection, biodegeneration, or aneurysmal formation. Our preliminary experience with this cost-effective locally produced human umbilical vein graft material was promising and may pave the way to further clinical applications.

Heterogeneity of anion exchangers mediating chloride transport in the proximal tubule

Three distinct anion exchangers are described that directly or indirectly mediate Cl- transport across the luminal membrane of the proximal tubule cell. Studies on the intact proximal tubule indicate that the Cl(-)-formate exchanger is a major mechanism for Cl- transport under physiologic conditions. As just discussed, the physiologic importance of the Cl(-)-oxalate and SO4 = (oxalate)-CO3 = exchangers mediating Cl- transport across the luminal membrane of the proximal tubule cell is currently unknown. These three anion exchangers are part of a larger group of at least eight distinct anion transporters in the proximal tubule that share with erythrocyte Band 3 the properties of stilbene sensitivity and/or the ability to mediate anion exchange. It is tempting to speculate that these proximal tubule anion transporters are members of a family of proteins structurally related to the prototypic anion exchanger, erythrocyte Band 3. If this is true, comparing the structures of these anion transporters with each other and with Band 3 should provide important insight into the molecular basis for differences in substrate and inhibitor specificity within this family of transport proteins.

Superior mesenteric vein severance from blunt abdominal trauma: report of a case

Injury of the superior mesenteric vein from blunt abdominal trauma is an uncommon but frequently fatal injury. A 63-year-old man was injured in a motorcycle accident. He was admitted to our hospital in profound shock. Immediate celiotomy revealed superior mesenteric vein injury which was repaired by end-to-end anastomosis. Rapid fluid resuscitation and expeditious exploration are the key in saving patients with this condition. Indications for exploration of retroperitoneal hematomas, techniques of exposure, modes of reconstruction of the injured vein and the importance of a second-look operation are discussed.

[A new operation for the management of gastric varix bleeding]

Gastric varices is a special oriental type manifestation of gastroesophageal collaterals in portal hypertension patients. It has gained more attention in recent years following the popularity of endoscopy and sclerotherapy. Catastrophic bleeding from ruptures of gastric varices is a life threatening emergency. Gastric varices are generally located at the greater curvature side of the cardiofundic region. Neither a Sengstaken-Blakemore balloon tube nor a Linton balloon tube can stop the bleeding. This area is also beyond the field of sclerotherapy. Surgery is the only definite therapy. Devascularization procedures as described by Dr. Hassab sometimes fail to control active bleeding and also fail to adequately decongest the whole varices area. The radical resection procedures such as terminal esophagectomy, proximal gastrectomy or cardiectomy as proposed by Japanese groups interrupts the normal esophgo-gastric continuity and is also too invasive for a cirrhotic patient. In between, besides terminal esophago-proximal gastric devascularization and splenectomy, we use a TA-90 stapler to perform an oblique cardiofundectomy to resect en bloc the tortuous gastric varices area. From Nov. 1983 to May 1988, at the Veterans General Hospital-Taipei, 16 patients received this new operation to manage gastric varices bleeding. Ten of them were on an emergency basis and 6 were elective surgery. Only one patient in the emergency group died. All catastrophic bleeding in the emergency group was dramatically controlled and all other patients recovered rapidly. With a follow-up range from 6 months to 4.5 year and an average of 19 months, there was no recurrent bleeding and no hepatic encephalopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxalate transport via the sulfate/HCO3 exchanger in rabbit renal basolateral membrane vesicles

We evaluated the mechanism of oxalate transport in basolateral membrane vesicles isolated from the rabbit renal cortex. An outward HCO3- gradient induced the transient uphill accumulation of oxalate and sulfate, indicating the presence of oxalate/HCO3- exchange and sulfate/HCO3- exchange. For oxalate, sulfate, or 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, the K1/2 value for oxalate/HCO3- exchange was nearly identical to that for sulfate/HCO3- exchange, suggesting that both exchange processes occur via the same transport system. This was further supported by the finding of sulfate/oxalate exchange. Thiosulfate/sulfate exchange and thiosulfate/oxalate exchange were also demonstrated, but a variety of other tested anions including Cl-, p-aminohippurate, and lactate did not exchange for sulfate or oxalate. Na+ did not affect sulfate or oxalate transport, indicating that neither anion undergoes Na+ co-transport or Na+-dependent anion exchange in these membrane vesicles. Finally, we found that the stoichiometry of exchange is 1 sulfate or oxalate per 2 HCO3-, or a thermodynamically equivalent process. We conclude that oxalate, but not other organic or inorganic anions of physiologic importance, can share the sulfate/HCO3- exchanger in renal basolateral membrane vesicles. In series with luminal membrane oxalate/Cl- (formate) exchange, exchange of oxalate for HCO3- or sulfate across the basolateral membrane provides a possible transcellular route for oxalate transport in the proximal tubule.

Postoperative deep vein thrombosis in the Taiwanese Chinese population

Reports of the incidence of postoperative deep vein thrombosis in the Chinese population of Taiwan are few in the literature. Over a 3 year period, the fibrinogen degradation products test, the pulse volume recorder, and venography were used to study 220 patients undergoing major operations at the Veterans General Hospital in Taipei, Taiwan. Deep vein thrombosis was found in 17 patients (7.7 percent). A comparison of the three diagnostic methods showed that the sensitivities of the fibrinogen degradation products test and the pulse volume recorder were 56.3 percent and 93.7 percent, respectively; the specificities, 97.4 percent and 95.7 percent, respectively; and the accuracies, 85.5 percent and 95.5 percent, respectively. These results support the combined use of the fibrinogen degradation products test and the pulse volume recorder for screening and diagnosing deep vein thrombosis.

Urate and p-aminohippurate transport in isolated kidney tubules of normal and hyperuricemic chickens

Urate and p-aminohippurate accumulations of kidney tubule fragments were studied in 5- to 6-week-old normal (LUA) and hyperuricemic (HUA) chickens. Tubules from LUA chicks consistently accumulated two to three-fold as much urate and p-aminohippurate as tubules from HUA chicks and thus confirmed the tubular origin of the urate transport defect in HUA chickens. A sodium gradient was required for optimal urate and p-aminohippurate accumulations and ouabain inhibited the accumulations of both compounds. Similar responses of urate and p-aminohippurate to treatments and reciprocal inhibitions between these compounds suggest that urate and p-aminohippurate are accumulated through a shared transport system.

Carrier-mediated transport of urate by chicken (Gallus domesticus) renal brush-border membrane vesicles

1. Urate is transported by an anion exchange system in chicken renal brush-border membrane vesicles. An outward chloride gradient stimulates an overshoot in urate uptake. 2. The anion exchanger is similar to those described for the kidneys of rats and dogs except that the chicken exchanger has a higher specificity for urate. 3. p-Aminohippurate has only a weak affinity, if any, for the urate exchanger. 4. There were no apparent qualitative differences in urate transport between brush-border membrane vesicles from genetically normouricemic and hyperuricemic chickens.

Changes in maternal taurine levels in response to pregnancy and lactation

Taurine levels in various tissues and fluids of female rats were measured throughout pregnancy and lactation. The taurine concentration of liver markedly increased at days 19 and 21 of pregnancy to 188% of levels for nonpregnant, nonlactating control rats and then fell rapidly after delivery to reach only 30% of the control level by 3 days postpartum. Muscle and heart taurine concentrations were significantly negatively correlated with liver taurine levels. Brain taurine levels were low at days 14, 19 and 21 of pregnancy and day 14 of lactation. Urinary excretion of taurine decreased to 32% of control levels at day 21 of pregnancy and was negatively correlated with the hepatic taurine concentration over the course of pregnancy and lactation. The ratio of glycine- to taurine-conjugated bile acids was strongly negatively correlated with the hepatic taurine concentration. The milk taurine level was positively correlated with hepatic taurine concentration during lactation. The hepatic taurine pool appears to increase just before parturition and to rapidly decrease during the first few days of lactation when high levels of taurine are secreted in the milk. Our data suggests that the accumulation of taurine in the liver may be related to both a decreased renal clearance of taurine and a shifting of tauring from other tissues to the liver and that this enlarged pool of hepatic taurine may serve as a source of taurine for secretion in the early milk.