Relationship between brain serotonin and calmodulin in young, genetically obese (ob/ob) mice

The possible relationships between altered brain serotonin and calmodulin contents on the development of obesity were studied. Eight groups of mice separated by differences in phenotype, sex and age were used in this study. The brain contents of tryptophan, serotonin, 5-hydroxyindoleacetic acid (5-HIAA) and calmodulin were assayed. The contents of brain tryptophan showed no significant differences in any of the mice. The amount of brain serotonin in obese mice was 82% higher than that in their lean counterparts at four weeks of age, but only 11% higher at eight weeks of age. Regardless of age and sex, brain serotonin was positively correlated to the brain calmodulin in the lean mice (r = 0.559, p < 0.01), yet this was not found in obese mice. There was a strong positive correlation between serotonin and 5-HIAA in all mice (r = 0.679, p < 0.001). The elevated amount of serotonin in the brain of four-week-old obese mice is suggested to have important effects on thermoregulation in young genetically obese mice. The results also suggest that abnormal brain serotonin synthesis in obese mouse regulated by calmodulin might interact with certain factors, such as calcium ions, to complete the activation of serotonin-synthesized enzymes in the development of obesity.

[Investigation of the profile of selected trace metals in genetically obese (ob/ob) and lean (+/?) mice]

Trace metals are known to have important effects on the activity of metalloenzymes and insulin secretion and to be involved in the etiology of various diseases. This study was designed to investigate the distribution and concentration of selected trace metals in the tissues of genetically obese mice, which were known to have hyperinsulinemia. Different phenotypes (ob/ob; +/?) and sexes of 4, 8, 12 week-old mice were killed by decapitation. Metal levels (Zn, Cu, Cd, Cr) in the brain, liver, serum, hair and carcass were determined by an atomic absorption spectrometer. The results showed that obese mice had lower concentrations of zinc in the serum, hair, liver and carcass than lean controls (p less than 0.05), but there was no difference in the brain. Obese mice also had a low carcass cadmium concentration (p less than 0.01), which depended on the sex-age interaction. When expressed in terms of total content, obese mice had higher total liver zinc and carcass chromium contents (p less than 0.05). Obese mice had a higher total carcass copper content at 8 weeks of age. Serum and carcass zinc were showed to be inversely related to body fat in obese mice. The results indicate that zinc may play a special role in thermoregulation and fat metabolism in the liver of obese mice. The tissue distribution and absorption of zinc may have an important correlation in the development of obesity. The roles of copper, cadmium and chromium are still obscure, the related regulations are still open for further questions.(ABSTRACT TRUNCATED AT 250 WORDS)

Recognition of substrates by tyrosylprotein sulfotransferase. Determination of affinity by acidic amino acids near the target sites

The sulfation of proteins by tyrosylprotein sulfotransferase (TPST) is highly site-specific. In this study, we examined the sequence specificity of the target site for TPST by determining the kinetics of rat liver TPST with peptides related to the sequence of the C4 component of complement. The data obtained from this study demonstrate that selective elimination of negative charges from the -5 to +5 region of the acceptor tyrosine, either by removal or by isosteric substitution or the acidic amino acids in the region, produced a substantial change in the Km value, with relatively little effect on Vmax. Substitutions at -1 and +1 positions increase the Km value by 22- and 4-fold, respectively, whereas removal of the acidic amino acids from the -5, -4, or +4 positions increased the Km values by a factor of 2-4. The effect of elimination of an acidic amino acid on the Km value was constant and specific for its particular position in relation to tyrosine, and the effect of modification of more than one amino acid was multiplicative. This study provides evidence that: 1) acidic residues near tyrosines promote sulfation by increasing the affinity of enzyme-substrate binding and have little effect on catalytic rate; 2) the contribution of each acidic residue to affinity for TPST is independent and varies according to position relative to the acceptor tyrosine; and 3) the enzyme interacts with a segment of at least 4-5 residues on each side of the tyrosine, with the residues on the -1 and +1 positions being the most important determinants. In general, residues on the NH2-terminal side of the tyrosine have a greater effect on affinity for TPST.

[Investigation of the relationships between zinc and obesity]

Zinc is known to be an essential trace metal which is necessary for health and growth, and is also essential for the function and activity of over 200 metalloenzymes. A relationship between zinc and obesity was first found in obese patients and obese mice (genetically and dietary obese) to that the obese had lower blood zinc levels than their lean controls, and the zinc level was inversely related to the degree of obesity. The therapeutic effect of zinc on obesity is still a controversial subject. This study was to investigate the alterations of tissues zinc distribution, dietary zinc effect in obese mice, and the interactive combinations of zinc and endocrine factors in obese patients. Zinc and body fat contents were determined by atomic absorption spectrometer and gravimetrically, respectively. The results indicated that dietary zinc treatment increased body fat deposition in obese mice. Obese mice carried markedly low zinc levels in most of the peripheral tissues, but retained a great amount of zinc in liver and adipose tissues compared with lean mice. Clinically, zinc was found to be correlated with thyroid hormone conversion and insulin resistance. Although the true metabolic role of zinc in obesity is still obscure, the relationships between zinc, endocrine factors, and neurotransmitters, and interactions with other trace metals are needed to throw light on the subject. These approaches to thermoregulation and metabolic mechanisms of obesity and diabetes mellitus may be of great interest in the future.

[Zinc sulfate and thyroxine treatment on the obese patients]

Zinc has recently been found to have important effects on metabolism and thermoregulation of obese individuals. The effects of zinc sulfate and thyroxine treatment on the obese patients were studied. The obese patients, selected from outpatients at the Taichung VGH, all had their body weight 20% higher than they normally should have, and body mass indexes (BMI = Wt/Ht2) greater than 25 kg/m2. They were separated into three groups to have 600mg zinc sulfate or/and 0.1mg thyroxine per day, respectively. Serum zinc and copper contents were determined by atomic absorption spectrometer. The alterative of body weight was also recorded. After 8 weeks of therapy, the zinc sulfate and zinc sulfate + thyroxine treatment had more significant effects on weight reduction (male: -1.10 +/- 0.38; -1.10 +/- 0.19, female: -1.75 +/- 0.19; -3.16 +/- 0.21 kg, P less than 0.05, respectively). The serum zinc content was found to inversely relate to the body weight reduction (r = -0.605, P less than 0.001). The results also showed that zinc sulfate and thyroxine treatment did not have satisfactorily greater effects on body weight reduction at short-term therapy on obese patients. We conclude that zinc therapy on the obese patients still need more evaluation and suggest that zinc may have important effects on the thyroid hormones conversion, and may have certain regulatory effects on the insulin activity through its interaction with thyroid hormones in the development of obesity.

2-Chloroadenosine decreases tyrosylprotein sulfotransferase activity in the Golgi apparatus in PC12 cells. Evidence for a novel receptor

In the present studies, we investigated the activity of tyrosylprotein sulfotransferase (TPST) in the Golgi apparatus of PC12 cells and the regulation of this enzyme by 2-chloroadenosine, an adenosine receptor agonist. Studies employing continuous sucrose gradient and trypsinization of the membranes demonstrate that TPST is located on the luminal side of Golgi apparatus in PC12 cells. Treatment of PC12 cells with 2-chloroadenosine results in a dose-dependent decrease of TPST activity which is observable as early as 3 h after initiation of treatment, maximizes at 24-48 h with continuous exposure, and is readily reversible upon removal of the drug. While forskolin, an agent that directly increases intracellular cAMP, has no effect on TPST activity, 2-chloroadenosine equally suppressed the enzyme activity in both the wild type and a protein kinase A-deficient mutant strain of PC12 cells, indicating that such regulation of TPST activity by 2-chloroadenosine was independent of cAMP-dependent protein phosphorylation. This effect of 2-chloroadenosine can be potentiated by an adenosine uptake blocker dipyridamole but cannot be elicited by other adenosine A1 or A2 receptor agonists, further suggesting that TPST activity in PC12 cells is regulated by 2-chloroadenosine via a novel membrane receptor. Incubation of the cells with cyclo heximide, a protein synthesis inhibitor, also led to a time- and dose-dependent suppression of TPST activity. At concentrations of cycloheximide that produced maximal inhibition (approximately 50%), cotreatment with 2-chloroadenosine did not lead to a further decrease of the TPST activity. These results suggest that the sensitivity of TPST activity to be controlled by protein synthesis provides a mechanism for regulation of its activity by 2-chloroadenosine.

Increase in beta-1,4-galactosyltransferase activity during PC12 cell differentiation induced by forskolin and 2-chloroadenosine

Galactosyltransferase (GALTase) activity was measured in differentiating PC12 cells induced by either forskolin or 2-chloroadenosine. The specific activity of GALTase in whole cells and isolated Golgi membranes increased as early as 3 h after initiating treatment with 2-chloroadenosine, and maximal activity was reached at approximately 12 h. In two mutant PC12 cell lines deficient in protein kinase A, both forskolin and 2-chloroadenosine failed to increase GALTase activity. The adenosine A2 receptor antagonist, xanthine amine congener, prevented 2-chloroadenosine stimulation of GALTase, demonstrating that this adenosine derivative was mediating its effect via the A2 receptor. These data suggest that GALTase activity during PC12 cell differentiation is regulated by cyclic AMP (cAMP)- and protein kinase A-dependent processes. In support of the role of cAMP in regulating GALTase activity were studies with murine PC carcinoma cells demonstrating that the greatest stimulation of GALTase activity occurred with cells treated with both retinoic acid and dibutyryl cAMP.

[Diabetic foot infections: a preliminary report]

Foot infection is a common cause of hospitalization for diabetic patients. Our study aimed to analyze patients' age, sex, the primary sites of infection, presenting features, outcome, bacteriologic studies and their clinical significance in diabetic foot infections. The age of our diabetic patients with foot infections ranged from 43 to 82 years, with a mean of 62.5 years; fifty-two of them were males and twenty-eight were females. The male to female ratio was 1.9:1, but there was no statistically significant difference between the sexes (p greater than 0.05). The commonest age group was the seventh decade of life (47.5%), followed by the sixth decade (32.5%). The commonest primary site of infection was the toes (53.8%), followed by foot area other than toe (25%) and the leg area was the least frequent (21.2%). Cellulitis combined with other foot lesions presented in 78.8% of these patients, foot ulcers in 75% of them, gangrenous change in 68%, necrotizing cellulitis or fasciitis in 16.3%, abscess formation in 12.5% and osteomyelitis in 7.5%. The legs were amputated in 53 patients (66.3%), usually below the knee (in 47.5%). We found that patients with a long history of DM had statistically significantly higher rate of amputation (p less than 0.01) than patients with only a brief history. Bacterial cultures from the infected foot lesions yielded numerous organisms in 58.8% of cases and a single organism in 31.1% of cases. Proteus mirabilis was the commonest organism isolated, followed by E. coli, Pseudomonas aeruginosa. The commonest month of the onset of diabetic foot infection was January, followed by February.

Chemical synthesis and surface activity of lung surfactant phospholipid analogs. II. Racemic N-substituted diether phosphonolipids

A series of racemic 16:0 disaturated N-substituted diether phosphonolipid analogs of glycerophospholipids have been synthesized and purified. Isosteric methylene substitution at three of the four ester sites (carboxyl, phosphate) of conventional glycerophospholipids enhanced the hydrophobicity of analog compounds compared with dipalmitoyl phosphatidylcholine (DPPC), the major glycerophospholipid component of lung surfactant. Further substitutions at the nitrogen headgroup also contributed to hydrophobicity/hydrophilicity characteristics, as well as allowing graded variations in headgroup size among the members of the diether phosphonolipid analog series. Interfacial property studies showed that these compounds had significant differences in surface activity characteristics compared with DPPC, including increased adsorption and respreading facility, plus an enhanced ability to generate low surface tension (less than 1 to 4 mN/m) on an oscillating bubble apparatus at 37 degrees C. In addition, pressure-volume mechanical studies in surfactant-deficient excised rat lungs showed that the diether phosphonate analog of DPPC could partially restore pressure-volume characteristics toward normal, both as a pure component and in binary mixtures with palmitoyl-oleoyl phosphatidylglycerol. These findings suggest that selected analog compounds, synthesized with relatively small structural modifications from biologic glycerophospholipids, may have eventual applications as components of synthetic exogenous lung surfactants. Of more immediate importance, analog molecules with defined structural variations are convenient molecular probes for developing structure-surface activity correlates for phospholipid-like surfactants and for investigating the specificity of interactions between glycerophospholipids and other compounds such as proteins.

Chemical synthesis and surface activity of lung surfactant phospholipid analogs. III. Chiral N-substituted ether-amide phosphonolipids

A homologous series of chiral (R) ether-amide phosphonolipid analogs of naturally occurring (R) glycerophospholipids were synthesized and characterized for their interfacial behaviors. The phosphonolipids possess isoteric ether, amide, and phosphonate functions at positions corresponding to the sn-1, sn-2, and sn-3 ester functions, respectively, of naturally occurring glycerophospholipids. All compounds were synthesized with disaturated C16:0 alkyl/acyl moieties to give structural analogy with dipalmitoyl phosphatidylcholine (DPPC), the major glycerophospholipid component of lung surfactant. Further substitutions at the headgroup nitrogen were also used to generate differences in headgroup size and polarity in the synthetic compounds. The surface activity of the ether-amide phospholipids was investigated in terms of adsorption to the air-water interface, together with studies of dynamic respreading after monolayer collapse and surface tension lowering in dynamically compressed spread films and dispersions. Results showed that several ether-amide phosphonolipids had more rapid adsorption and improved dynamic respreading behavior compared to DPPC, plus the ability to lower surface tension into the range of less than 1 to 4 mN/m in spread films and in dispersions under dynamic conditions. In combination with a series of diether phosphonolipids synthetized in a companion study [1], these ether-amide compounds are useful in the development of molecular structure-surface activity correlates for lung surfactant-related materials, and should assist in investigating the specificity of interactions between phospholipids and other pulmonary biological molecules.

Abnormal thyroid hormone levels in critical nonthyroidal illness

Low levels of thyroid hormone in the absence of clinical hypothyroidism often happen to patients with critical non-thyroidal illnesses (NTI). Low thyroid hormone concentrations in serum do not necessarily mean hypofunction of the thyroid gland; rather it is a helpful adaptation of the human body to the underlying diseases. We collected 133 hospitalized cases of critical NTI and analyzed the incidence of this phenomenon. Fifty-three per cent of the patients had T3 level lower than 60 ng/dl (normal:85-165 ng/dl) and 60% had T4 level lower than 6 ug/dl (normal:6-12 ug/dl). The lowest levels were observed in patients who had sepsis, were aged over 70 or died in this admission. Free T4 and TSH levels were within normal range in most cases. There is a strong negative correlation between the prognosis and the level of T4 in these patients. Those patients with markedly low levels of T3 and T4 should be treated more sophisticatedly.

Serotonin (5-HT1c) receptors in pig choroid plexus

It is very important to find suitable reaction conditions to attain a high specific binding (specific/total binding) in the receptor binding study. Membrane homogenates of pig choroid plexus are known to have exclusively serotonin (5-hydroxytryptamine, 5-HT) receptor of the subtype 5-HT1c. In this study, we used the membrane preparation of pig choroid plexus tissue and the specific binding of [3H]5-HT was 72-84% to serotonin receptor subtype 5-HT1c, as defined by the inhibition of 1 uM 5-HT, when a radioligand concentration of 0.5 nM of [3H]5-HT was used in the assay. Analysis of the properties of specific [3H]5-HT binding in pig choroid plexus tissue membrane preparation revealed linear Scatchard plots. In Tris-HCl buffer without CaCl2, pargyline or ascorbic acid, high average of affinity dissociation constant (Kd) of 1.3 +/- 0.2 nM (SEM, n = 4) and also a high average of receptor density (Bmax) of 284 +/- 12 fmol/mg of protein were found. Pig choroid plexus proves to be a good material for 5-HT1c receptor binding study.

Studies on bioactive components from Chinese medicinal plants

Several novel bioactive components isolated from Chinese medicinal plants will be presented. These include novel maytansinoid tumor inhibitors, some new ent-kaurane and rosane diterpenoids from Mallotus anomalus Meer et Chun (Euphorbiaceae), as well as novel insecticide, stemona alkaloids from Stemona parviflora C. H. Wright (Stemonaceae). Both are native plants of Hainan island, China. 2D NMR techniques such as mono and hetero-COSY, NOESY, COLOC as well as 1H-NMR line broadening effect were utilized for structure elucidation. The separation techniques, structure elucidations and bioassay results will be reported.

Phosphorylation of smooth muscle myosin by type II Ca2+/calmodulin-dependent protein kinase

Brain type II Ca2+/calmodulin-dependent protein kinase was found to phosphorylate smooth muscle myosin, incorporating maximally approximately 2 mol of phosphoryl per mol of myosin, exclusively on the 20,000 dalton light chain subunit. After maximal phosphorylation of myosin or the isolated 20,000 dalton light chain subunit by myosin light chain kinase, the addition of type II Ca2+/calmodulin-dependent protein kinase led to no further incorporation indicating the two kinases phosphorylated a common site. This conclusion was supported by two dimensional mapping of tryptic digests of myosin phosphorylated by the two kinases. By phosphoamino acid analysis the phosphorylated residue was identified as a serine. The phosphorylation by type II Ca2+/calmodulin-dependent protein kinase of myosin resulted in enhancement of its actin-activated Mg2(+)-ATPase activity. Taken together, these data strongly support the conclusion that type II Ca2+/calmodulin-dependent protein kinase phosphorylates the same amino acid residue on the 20,000 dalton light chain subunit of smooth muscle myosin as is phosphorylated by myosin light chain kinase and suggest an alternative mechanism for the regulation of actin-myosin interaction.

Characterization of a tyrosylprotein sulfotransferase in human liver

Sulfation of tyrosyl residue(s) has been found to be a post-translational modification that precedes the secretion of many biologically active proteins or peptides. In the present paper, we report on the characterization of human liver tyrosylprotein sulfotransferase (TPST), the enzyme responsible for sulfation of tyrosine in proteins. Using poly Glu,Ala,Tyr (6:3:1; EAY) as the model substrate, human liver TPST was recovered in the microsomal fraction after differential centrifugation. This enzyme displayed a pH optimum of 6.4 and was stimulated approximately 2.5-fold in the presence of 0.5% non-ionic detergents, such as Lubrol-PX and Triton X-100. The divalent cation Mn2+ was required for enzymatic activity and produced maximal activation at 30 mM, whereas other divalent cations, including Mg2+ and Co2+, failed to enhance sulfoconjugation at this concentration. Using the optimized assay condition, the apparent Km for EAY was found to be approximately 1.5 microM, with significant substrate inhibition at EAY concentrations above 2 microM. The 16 amino acid peptide of the C-terminus of C4 possessed an apparent Km of approximately 2.1 microM. Using EAY as a substrate, TPST activity was measured in liver samples from ten organ donors to detect the variability of this enzyme among human subjects. The activity in the male group (1.065 +/- 0.074 pmol/min/mg) was significantly (P less than 0.005) higher than that of the female group (0.662 +/- 0.158 pmol/min/mg), suggesting that TPST activity may be regulated, in part, by sex hormones.

[A survey on weight and height of children (1 month-7 years) and plotting of growth curves (1 month-18 years) in Taiwan, 1987-1988]

From July 1987 to December 1988, 19,625 children in Taiwan were measured for their body weights and heights. They were 9,564 boys and 10,061 girls and were seen either in a well baby clinic of a large community hospital or in the local kindergartens. We divided these children into 64 groups according to their sex and ages. The mean values and standard deviation of body weight and height were tried to correlate with those from children of school age reported for 1987 by the Ministry of Education. Furthermore, body weight and height growth curves were drawn for these children, aged from 1 month to 18 years.

Thyroid function during isoflurane anesthesia and valvular heart surgery

Proper thyroid function is essential for maintaining cardiovascular integrity during normal and stressful situations. In this study, the effects of isoflurane-O2 anesthesia and surgical stress on serum TSH, T4, free T4, T3, rT3, and cortisol were investigated in nine patients before, during, and after valve surgery. Compared with preoperative control values, serum TSH decreased in the postoperative period. Both T4 and free T4 had similar decreases after cardiopulmonary bypass (CPB) and remained depressed postoperatively. Both T3 and rT3 decreased at the start of cardiopulmonary bypass; T3 remained low in the postoperative period, while rT3 increased. Cortisol decreased during anesthesia and surgery in the prebypass period, but increased during cardiopulmonary bypass and in the postoperative period. The results suggest that isoflurane-O2 anesthesia during valve surgery produces a rapid decrease in T3, resulting in the low T3 syndrome postoperatively. Isoflurane, in the dose studied, similar to fentanyl, can suppress the cortisol response to anesthesia and surgery in the prebypass period, but not during and after CPB.

[A community-based study on risk factors of hypertension in Luh-Guu Township]

This is a community-based study on hypertension conducted in 1987 to assess the risk of demographic factors and life style of inhabitants aged over 30 in Luh-Guu Township. One-stage cluster sampling was applied. Through home visit interview, the height, weight, and blood pressure as well as demographic and life style data were taken, and 1171 (57.4%) valid data were completed. Hypertension was defined by American National Heart, Lung, Blood Institute as BP greater than = 140/90mmHg. The prevalence of hypertension was 29.2% (the prevalence was 13.4% if defined by the WHO criteria), and only 27.4% of those hypertensives were self-aware. Univariate analysis found that age, educational level, marital status, job condition, smoking habit, father's hypertension history, and usage of contraceptive were correlated with hypertension. With obesity index in addition to the above 6 factors, except contraceptive usage, as independent variables, the multiple logistic regression analysis showed that, only age and obesity index were significantly correlated with hypertension and the best model were fitted.

[Gemfibrozil in the treatment of hyperlipidemia]

An elevated serum cholesterol level is a well known major risk factor for developing atherosclerosis in general, and for coronary heart disease in particular. There are many lipid lowering agents currently available. We used gemfibrozil in twenty hyperlipidemic cases who failed to response to diet control for three months. They were thirteen males and seven females with their ages ranging from thirty to eighty-one year-old. They included ten diabetes, one nephrotic syndrome and nine pure hyperlipidemic patients. All cases received gemfibrozil 600mg twice daily for 4-12 weeks. Gemfibrozil caused an increase in HDL cholesterol. The reductions in serum level of total cholesterol, total cholesterol/HDL cholesterol, and triglyceride were found. Only one case developed mild gastrointestinal side effect. There was no other major side effects.

Zinc in hair and serum of obese individuals in Taiwan

Zinc concentrations in both serum and hair were assessed in 135 obese patients (51 males, 84 females) and in 57 controls (28 males, 29 females) to study the correlation between Zn and obesity. The body mass index (wt/ht2) was also measured to evaluate its relationship to the Zn level in obese individuals. The serum and hair Zn contents in obese patients were markedly lower than in normal control subjects by 22 and 34%, respectively. The Zn content was inversely related to the body mass index. Thus Zn may play an important metabolic role in the development of obesity.

Monoclonal antibodies specific for non-glycosylated porcine prolactin and for pituitary porcine prolactin

Glycosylated and non-glycosylated forms of porcine pituitary prolactin were prepared using Concanavalin A Sepharose chromatography. Anti-prolactin monoclonal antibodies were screened for their ability to distinguish these two forms. One monoclonal antibody (17D9) exhibited high affinity binding for the non-glycosylated form of porcine prolactin, but little or no affinity for the glycosylated form. Using this antibody in conjunction with other monoclonals which equally recognize both forms, we developed immunoassays which can be used to determine the amount of the glycosylated vs. non-glycosylated prolactin in serum or other tissue samples.

Effects of zinc and thyroxine treatment on dietary-obese mice

Altered thyroid hormone metabolism is known to be an important factor contributing to the defective expression of thermogenesis in the obese mouse, and the action of zinc on thyroid hormone conversion may be an important factor in the energy metabolism of obesity. The effects of zinc and thyroxine treatment on dietary-obese mice were examined. The dietary-obese mice were successfully induced by high-fat diet (80% fat), and every mouse was administered daily 1.25 mg zinc sulfate and/or 5 micrograms thyroxine. After 8 weeks of treatment, serum zinc, serum triacylglycerols and body fat composition were determined. On high-fat diets, fat deposition was found in male mice treated with zinc sulfate. However, when mice were treated with zinc and thyroxine at the same time, serum triacylglycerols and body fat composition decreased significantly on both basal and high-fat diets. When mice were treated with thyroxine alone, body fat composition decreased significantly, but there was no significant effect on serum triacylglycerols on either diet. Obesity was significantly correlated with dietary fat, zinc and thyroid hormone. It is suggested that zinc may play an important role, through its action on thyroid hormone conversion and via insulin action, in the energy metabolism of dietary-obese mice.