Characterization of the active site of ADP-ribosyl cyclase

ADP-ribosyl cyclase synthesizes two Ca(2+) messengers by cyclizing NAD to produce cyclic ADP-ribose and exchanging nicotinic acid with the nicotinamide group of NADP to produce nicotinic acid adenine dinucleotide phosphate. Recombinant Aplysia cyclase was expressed in yeast and co-crystallized with a substrate, nicotinamide. x-ray crystallography showed that the nicotinamide was bound in a pocket formed in part by a conserved segment and was near the central cleft of the cyclase. Glu(98), Asn(107) and Trp(140) were within 3.5 A of the bound nicotinamide and appeared to coordinate it. Substituting Glu(98) with either Gln, Gly, Leu, or Asn reduced the cyclase activity by 16-222-fold, depending on the substitution. The mutant N107G exhibited only a 2-fold decrease in activity, while the activity of W140G was essentially eliminated. The base exchange activity of all mutants followed a similar pattern of reduction, suggesting that both reactions occur at the same active site. In addition to NAD, the wild-type cyclase also cyclizes nicotinamide guanine dinucleotide to cyclic GDP-ribose. All mutant enzymes had at least half of the GDP-ribosyl cyclase activity of the wild type, some even 2-3-fold higher, indicating that the three coordinating amino acids are responsible for positioning of the substrate but not absolutely critical for catalysis. To search for the catalytic residues, other amino acids in the binding pocket were mutagenized. E179G was totally devoid of GDP-ribosyl cyclase activity, and both its ADP-ribosyl cyclase and the base exchange activities were reduced by 10,000- and 18,000-fold, respectively. Substituting Glu(179) with either Asn, Leu, Asp, or Gln produced similar inactive enzymes, and so was the conversion of Trp(77) to Gly. However, both E179G and the double mutant E179G/W77G retained NAD-binding ability as shown by photoaffinity labeling with [(32)P]8-azido-NAD. These results indicate that both Glu(179) and Trp(77) are crucial for catalysis and that Glu(179) may indeed be the catalytic residue.

Adriamycin release from flower-type polymeric micelle based on star-block copolymer composed of poly(gamma-benzyl L-glutamate) as the hydrophobic part and poly(ethylene oxide) as the hydrophilic part

Star-block copolymer based on PBLG as the hydrophobic part and PEO as the hydrophilic one (as abbreviated GEG) was synthesized and characterized. Polymeric micelle was prepared by the diafiltration method. From the measurement of photon correlation spectroscopy, the nanoparticle sizes of GEG-1, GEG-2 and GEG-3 were 106.5+/-59.2, 43.8+/-0.7 and 13.5+/-1.0 nm in number average, respectively, indicating of the formation of polymeric micelle. Also, the nanoparticle sizes were dependent on the PBLG chain length, i.e. the more PBLG content in the copolymer, the larger the particle size. From the observation of transmission electron microscope(TEM), GEG-2 block copolymer had almost spherical shapes with size range about 20-70 nm, that was similar to particle size measurement. Fluorescence spectroscopy measurement indicated that GEG block copolymers associated in water to form polymeric micelles and critical micelle concentration (CMC) values of the block copolymers decreased with increasing PBLG chain length in the block copolymer. Characteristic peaks of the protons of the benzyl group in the PBLG and the methylene protons adjacent to the benzyl group of the PBLG segment in the GEG-2 nanoparticles appeared in 7.2 approximately 7.4 and 5.0 approximately 5.2 ppm, respectively, and disappeared in D(2)O, indicating the restricted motions of these protons within the micellar core and the very rigid structure of the PBLG core in the GEG polymeric micelles. Release of ADR from the polymeric micelles in vitro was slower in longer PBLG chain length and higher loading contents of ADR.

NaOH treatment to neutralize inhibitors of Taq polymerase

The introduction of polymerase chain reaction (PCR) into the forensic field has greatly extended the ability to analyze DNA from small or degraded samples. However, one significant problem with PCR analysis is the sensitivity of Taq Polymerase to inhibitors found in many substrates commonly encountered with evidentiary materials. We hypothesize that the most problematic of these compounds intercalate into double stranded DNA (dsDNA) and have significantly less affinity for single stranded DNA (ssDNA). This study presents a comprehensive analysis of a novel method for the neutralization of Taq inhibitors by denaturation and washing with NaOH in Microcon-100 filtration units. The data show that DNA recovered following NaOH repurification routinely amplifies when other inhibitor neutralization techniques are unsuccessful. Genetic profiles have been obtained with both AmpliType PM + DQA1 and D1S80 systems. However, the NaOH protocol is not advised when the quantity of DNA is limited since the treatment results in significant loss of DNA.

Effects of long-acting somatostatin analogue (Sandostatin) on manifest diabetic ketoacidosis

Insulin deficiency and counterregulatory hormone excess are the basic process in the development of diabetic ketoacidosis (DKA). Somatostatin, which suppresses the secretion of glucagon and growth hormone, has been known to attenuate the rate of gluconeogesis and ketogenesis in insulin-dependent diabetes mellitus patients. However, the therapeutic efficacy of somatostatin has not been approved to be practical in the treatment of manifest DKA. To examine the additive effect of octreotide, the synthetic long-acting somatostatin analogue SMS 201-995, to conventional treatment of manifest DKA, we compared the correction time of acidosis, ketonuria, and hyperglycemia of patients treated with an intravenous infusion of low-dose insulin (4 units per hour) plus subcutaneous injection of octreotide (50 microg every 6 hours) by low-dose insulin alone. The correction time for hyperglycemia and acidosis did not show any difference between groups (p = 0.089, p = 0.82). However, the time for disappearance of ketonuria of the octreotide-treated group (38.0 +/- 32.0 h) was reduced significantly compared to other group (68.3 +/- 26.0 h) (p = 0.048). These results indicated that the addition of octreotide to conventional treatment of DKA might improve the correction of ketosis, but would not allow more rapid control of acidosis and hyperglycemia in manifest DKA.

A systematic analysis of PCR contamination

In light of the strict legal scrutiny surrounding DNA typing at this time, it has become necessary to systematically address the issue of PCR contamination. To precisely define the parameters affecting PCR contamination under casework analysis conditions, PCR amplification reactions were intentionally compromised by employing sub-standard laboratory technique and by introducing secondary sources of DNA. The PCR parameters considered for potential sources of contamination include amplification set-up, amplification product handling, aerosol DNA and storage. In addition, analyst technique was evaluated by modifying or eliminating standard safeguards. Under the circumstances normally encountered during casework analysis, PCR contamination was never noted. Significantly, using the dot blot detection method, contamination was never observed when nanogram quantities of genomic DNA were mishandled or aerosolized. Contamination occurred only when amplification product was carelessly manipulated or purposefully sprayed near or directly into open tubes containing water or genomic DNA. Although standard precautions should be employed during PCR-based DNA typing, our data indicates that contamination during amplification procedures is not prevalent when detected by dot blot analysis.

Development and testing of the Family Caregiving Consequences Inventory for home nursing assessment in Taiwan

This paper describes the development and psychometric testing of the Family Caregiving Consequences Inventory (FCCI). Data were collected from a convenience sample of 97 families in Taiwan to examine the validity and reliability of the three FCCI scales: frail elder outcomes, caregiver outcomes and family outcomes. Acceptable test-retest and internal consistency reliabilities were found, though inter-rater reliability was unsatisfactory. Criterion-related validity was demonstrated by congruence with home nursing specialists' assessment of family caregiving outcomes. Confirmatory factor analysis with a good overall model fit supported the construct validity of FCCI. However, a poor fit of the internal measurement structure was found for the frail elder outcomes scale and the family outcome scale. Studies with larger samples are needed to further verify the measurement models used here. Nevertheless, in its current form, the FCCI can be used to increase the sensitivity of home care nurses to family caregiving situations and provide an instrument for studies of family caregiving in Taiwan and other countries with similar home care needs.

Pancreatic tumors in children: report of three cases

From 1981 to 1996, we experienced 3 cases of pancreatic tumors in children--two pancreatoblastomas (PB) and one solid and cystic tumor (SCT). The ages were 1 month, 4 years, and 13 years of age respectively. The two cases of pancreatoblastoma initially presented as chronic diarrhea with failure to thrive, the other case presented with abdominal mass. All of them were studied by laboratory examination, ultrasonography, computed tomography and pathology. Increasing alpha- fetoprotein (AFP) levels were found in the 2 pancreatoblastoma cases, however, the level in the SCT case was normal. Abdominal sonography showed pancreatic masses with or without calcification, and the echogenicity may be solid and/or cystic. All patients underwent total excision of the tumors. We have reviewed the literature and find no pancreatoblastoma with chronic diarrhea was reported in young children, especially in neonate. Therefore, we suggest that young children presenting with an abdominal mass and/or weight loss should undergo imaging studies for the possibility of pancreatic tumors.

Effects of epoxyeicosatrienoic acids on the cardiac sodium channels in isolated rat ventricular myocytes

1. Whole-cell Na+ currents (holding potential, -80 mV; test potential, -30 mV) in rat myocytes were inhibited by 8, 9-epoxyeicosatrienoic acid (8,9-EET) in a dose-dependent manner with 22+/-4% inhibition at 0.5 microM, 48+/-5% at 1 microM, and 73+/-5% at 5 microM (mean +/- S.E.M., n = 10, P<0.05 for each dose vs. control). Similar results were obtained with 5,6-, 11,12-, and 14,15-EETs, while 8,9-dihydroxyeicosatrienoic acid (DHET) was 3-fold less potent and arachidonic acid was 10- to 20-fold less potent. 2. 8,9-EET produced a dose-dependent, hyperpolarized shift in the steady-state membrane potential at half-maximum inactivation (V ), without changing the slope factor. 8,9-EET had no effect on the steady-state activation of Na+ currents. 3. Inhibition of Na+ currents by 8,9-EET was use dependent, and channel recovery was slowed. The effects of 8,9-EET were greater at depolarized potentials. 4. Single channel recordings showed 8,9-EET did not change the conductance or the number of active Na+ channels, but markedly decreased the probability of Na+ channel opening. These results were associated with a decrease in the channel open time and an increase in the channel closed times. 5. Incubation of cultured cardiac myocytes with 1 microM [3H]8,9-EET showed that 25% of the radioactivity was taken up by the cells over a 2 h period, and most of the uptake was incorporated into phospholipids, principally phosphatidylcholine. Analysis of the medium after a 2 h incubation indicated that 86% of the radioactivity remained as [3H]8,9-EET while 13% was converted into [3H]8,9-DHET. After a 30 min incubation, 1-2% of the [3H]8,9-EET uptake by cells remained as unesterified EET. 6. These results demonstrate that cardiac cells have a high capacity to take up and metabolize 8,9-EET. 8,9-EET is a potent use- and voltage-dependent inhibitor of the cardiac Na+ channels through modulation of the channel gating behaviour.

Modulation of rat cardiac sodium channel by the stimulatory G protein alpha subunit

1. Modulation of cardiac sodium currents (INa) by the G protein stimulatory alpha subunit (Gsalpha) was studied using patch-clamp techniques on freshly dissociated rat ventricular myocytes. 2. Whole-cell recordings showed that stimulation of beta-adrenergic receptors with 10 microM isoprenaline (isoproterenol, ISO) enhanced INa by 68.4 +/- 9.6 % (mean +/- s.e.m.; n = 7, P < 0.05 vs. baseline). With the addition of 22 microgram ml-1 protein kinase A inhibitor (PKI) to the pipette solution, 10 microM ISO enhanced INa by 30.5 +/- 7.0 % (n = 7, P < 0.05 vs. baseline). With the pipette solution containing both PKI and 20 microgram ml-1 anti-Gsalpha IgG or 20 microgram ml-1 anti-Gsalpha IgG alone, 10 microM ISO produced no change in INa. 3. The effect of Gsalpha on INa was not due to changes in the steady-state activation or inactivation curves, the time course of current decay, the development of inactivation, or the recovery from inactivation. 4. Whole-cell INa was increased by 45.2 +/- 5.3% (n = 13, P < 0.05 vs. control) with pipette solution containing 1 microM Gsalpha27-42 peptide (amino acids 27-42 of rat brain Gsalpha) without altering the properties of Na+ channel kinetics. Furthermore, application of 1 nM Gsalpha27-42 to Na+ channels in inside-out macropatches increased the ensemble-averaged INa by 32.5 +/- 6.8 % (n = 8, P < 0.05 vs. baseline). The increase in INa was reversible upon Gsalpha27-42 peptide washout. Single channel experiments showed that the Gsalpha27-42 peptide did not alter the Na+ single channel current amplitude, the mean open time or the mean closed time, but increased the number of functional channels (N) in the patch. 5. Application of selected short amino acid segments (Gsalpha27-36, Gsalpha33-42 and Gsalpha30-39) of the 16 amino acid Gsalpha peptide (Gsalpha27-42 peptide) showed that only the C-terminal segment of this peptide (Gsalpha33-42) significantly increased INa in a dose-dependent fashion. These results show that cardiac INa is regulated by Gsalpha via a mechanism independent of PKA that results in an increase in the number of functional Na+ channels. In addition, a 10 residue domain (amino acids 33-42) near the N-terminus of Gsalpha is important in modulating cardiac Na+ channels.

Protective effect of chlormethiazole, a sedative, against acetaminophen-induced liver injury in mice

OBJECTIVES

The hepatotoxicity of acetaminophen is not a result of the parent compound but is mediated by its reactive metabolite N-acetyl-p-benzoquinone imine. Cytochrome P4502E1 (CYP2E1) is the principal enzyme of this biotransformation, which accounts for approximately 52% of the bioactivation in human microsomes. Recently, chlormethiazole a sedative drug, is reported to be an efficient inhibitor of CYP2E1 activity in human beings. In this study we wished to evaluate whether chlormethiazole, an inhibitor of CYP2E1, could prevent acetaminophen-induced liver injury in mice.

METHODS

Acetaminophen, at doses ranging from 200 to 600 mg/kg, was injected into the peritoneum of female C57BL/6 inbred mice fasted for four hours. Chlormethiazole (60 mg/kg) or 5% dextrose water was given 30 min before or 2 h after acetaminophen. Serum aminotransferase activities, histologic index score, survival rate and hepatic malondialdehyde levels were compared.

RESULTS

Pretreatment with chlormethiazole 30 min before 400 mg/kg of acetaminophen completely inhibited acetaminophen-induced liver injury (median 118.5 U/L, range 75 to 142 vs. 14,070 U/L, range 5980 to 27,680 for AST; 49 U/L, range 41 to 64 vs. 15,330 U/L, range 13,920 to 15,940 for ALT). In mice receiving chlormethiazole 2 h after acetaminophen, the mean AST and ALT levels were also less elevated, reaching only 20% of the value of acetaminophen-only group. These protective effects were confirmed histologically. Whereas more than 50% of mice died at 500 mg/kg of acetaminophen, all the mice pretreated with chlormethiazole survived at the same dose.

CONCLUSION

Chlormethiazole effectively reduces acetaminophen-induced liver injury in mice. Further studies are needed to assess its role in humans.

A unified mechanism of enzymatic synthesis of two calcium messengers: cyclic ADP-ribose and NAADP

Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP) mobilize Ca2+ from two different types of intracellular stores and through completely independent mechanisms. The two Ca2+ messengers are also structurally distinct. cADPR is a cyclic nucleotide derived from NAD, while NAADP is a linear metabolite of NADP. Systems responsive to these two novel signaling molecules are widespread among eukaryotes and include protozoan, plant, invertebrate, mammalian as well as human cells. Despite their functional and structural differences, cADPR and NAADP are sibling messengers synthesized by a single enzyme, ADP-ribosyl cyclase. In this article the recent progress in understanding the physiological roles of cADPR and NAADP is briefly reviewed. A unified mechanism of catalysis is also proposed, which takes into consideration the crystallographic structure of ADP-ribosyl cyclase and accounts for its novel multi-functionality.

A PCR analysis of ERalpha and ERbeta mRNA abundance in rats and the effect of ovariectomy

To study the relative abundance and the changes of both estrogen receptor alpha (ERalpha) and ERbeta mRNA before and after ovariectomy in major organs important to the regulation of calcium homeostasis, we compared the degree of mRNA expression of ERalpha to that of ERbeta in rat tissues by performing competitive reverse transcription polymerase chain reaction (RT-PCR) with internal standards. Both ERalpha and ERbeta were highly expressed in the ovary {ERalpha[(2.2 +/- 0.33) x 10(7) copies/microg of total RNA] > ERbeta[(1.2 +/- 0.33) x 10(5) copies/microg of total RNA]} as we expected. The bone marrow and renal cortex were very important target organs of estrogen because ERalpha was highly expressed approximately 2 x 10(5) copies/microg of total RNA, but marrow cells revealed only a very weak expression of ERbeta [(0.7 +/- 0.21) x 10(2) copies/microg of total RNA]. Both ERalpha and ERbeta were expressed in the trabecular bone [(3.2 +/- 0.56) x 10(3) copy/microg of RNA] and [(2.8 +/- 0.21) x 102 copy/microg of RNA], respectively. However, they were not detected in the cortical bone. In the jejunum, the expression of ERalpha was not detectable, while ERbeta was expressed very weakly [(1.1 +/- 0.24) x 10(2) copies/microg of total RNA]. The thyroid gland expressed low copy numbers of ERbeta [(6.0 +/- 0.23) x 10(2) copies/microg of total RNA], but the parathyroid gland was negative for both ERalpha and ERbeta mRNA. In cultured stromal cells, ERalpha and ERbeta mRNAs were not detected after a 24-h culture; however, the rates of mRNA expression of ERalpha and ERbeta reached approximately 105 copies/microg of total RNA and approximately 10(2) copies/microg of total RNA, respectively, after 9-, 11-, and 13-day cultures. After ovariectomy, the expression of ERalpha mRNA decreased abruptly in the bone marrow and renal cortex, and both ERalpha and ERbeta were barely detected in the trabecular bone. In conclusion, ERalpha might be the main ER in organs important for calcium homeostasis, except in the jejunum. The mRNA expression of ERalpha in the bone marrow and renal cortex decreased abruptly after ovariectomy, which may partially explain why the effect of estrogen deficiency can be amplified and why trabecular bone loss is more predominant than cortical bone loss shortly after surgical or natural menopause.

Polyelectroylte complex composed of chitosan and sodium alginate for wound dressing application

Drug-impregnated polyelectrolyte complex (PEC) sponge composed of chitosan and sodium alginate was prepared for wound dressing application. The morphological structure of this wound dressing was observed to be composed of a dense skin outer layer and a porous cross-section layer by scanning electron microscopy (SEM). Equilibrium water content and release of silver sulfadiazine (AgSD) could be controlled by the number of repeated in situ PEC reactions between chitosan and sodium alginate. The release of AgSD from AgSD-impregnated PEC wound dressing in PBS buffer (PH = 7.4) was dependent on the number of repeated in situ complex formations for the wound dressing. The antibacterial capacity of AgSD-impregnated wound dressing was examined in agar plate against Pseudomonas aeruginosa and Staphylococcus aureus. From the behavior of antimicrobial release and the suppression of bacterial proliferation, it is thought that the PEC wound dressing containing antimicrobial agents could protect the wound surfaces from bacterial invasion and effectively suppress bacterial proliferation. In the cytotoxicity test, cellular damage was reduced by the controlled released of AgSD from the sponge matrix of AgSD-medicated wound dressing. In vivo tests showed that granulation tissue formation and wound contraction for the AgSD plus dihydroepiandrosterone (DHEA) impregnated PEC wound dressing were faster than any other groups.

Low-dose growth hormone treatment with diet restriction accelerates body fat loss, exerts anabolic effect and improves growth hormone secretory dysfunction in obese adults

Growth hormone (GH) can induce an accelerated lipolysis. Impaired secretion of GH in obesity results in the consequent loss of the lipolytic effect of GH. Dietary restriction as a basic treatment for obesity is complicated by poor compliance, protein catabolism, and slow rates or weight loss. GH has an anabolic effect by increasing insulin-like growth factor (IGF)-I. We investigated the effects of GH treatment and dietary restriction on lipolytic and anabolic actions, as well as the consequent changes in insulin and GH secretion in obesity. 24 obese subjects (22 women and 2 men; 22-46 years old) were fed a diet of 25 kcal/kg ideal body weight (IBW) with 1.2 g protein/kg IBW daily and were treated with recombinant human GH (n = 12, 0.18 U/kg IBW/week) or placebo (n = 12, vehicle injection) in a 12-week randomized, double-blind and placebo-controlled trial. GH treatment caused a 1.6-fold increase in the fraction of body weight lost as fat and a greater loss of visceral fat area than placebo treatment (35.3 vs. 28.5%, p < 0.05). In the placebo group, there was a loss in lean body mass (-2.62 +/- 1.51 kg) and a negative nitrogen balance (-4.52 +/- 3.51 g/day). By contrast, the GH group increased in lean body mass (1.13 +/- 1.04 kg) and had a positive nitrogen balance (1.81 +/- 2.06 g/day). GH injections caused a 1.6-fold increase in IGF-I, despite caloric restriction. GH response to L-dopa stimulation was blunted in all subjects and it was increased after treatment in both groups. GH treatment did not induce a further increase in insulin levels during an oral glucose tolerance test (OGTT) but significantly decreased free fatty acid (FFA) levels during OGTT. The decrease in FFA area under the curve during OGTT was positively correlated with visceral fat loss. This study demonstrates that in obese subjects given a hypocaloric diet, GH accelerates body fat loss, exerts anabolic effects and improves GH secretion. These findings suggest a possible therapeutic role of low-dose GH with caloric restriction for obesity.

Gastro-intestinal bleeding caused by leiomyoma of the small intestine in a child with neurofibromatosis

Gastro-intestinal bleeding is an uncommon presentation in children with neurofibromatosis. Gastro-intestinal involvement caused by jejunal leiomyoma has only been described in adults. To the best of our knowledge, this is the first paediatric case of jejunal leiomyoma associated with neurofibromatosis. We present a 10-year-old girl with a 9-month history of anaemia and low gastro-intestinal bleeding. Abdominal sonography and small bowel series showed a submucosal mass in the proximal jejunum. On surgery, a submucosal tumour was excised and histological examination suggested a diagnosis of "smooth muscle tumour of undetermined malignant potential". There were no recurrence of symptoms for 4 years after the operation.

CONCLUSION

Jejunal leiomyoma should be considered in a child with neurofibromatosis presenting with gastro-intestinal bleeding.

Immunogenicity and reactogenicity of two recombinant hepatitis B vaccines in healthy adolescents on two-dose schedule

This is an open, randomized study to compare the immunogenicity and reactogenicity of two recombinant hepatitis B virus (HBV) vaccines. The HBV-NF is a new formulation with a new adjuvant phenoxyethanol which replaced the conventional adjuvant of a commercially available recombinant HBV vaccine (Engerix-B). These two vaccines had the same 20 micrograms hepatitis B surface antigen (HBsAg). They were administered to the deltoid muscle of 116 healthy adolescents, aged between twelve and eighteen years, according to the 0, 6-month schedule. Serum was taken at month 0, 1, 6, and 7. Antibody to HBsAg was tested by radioimmunoassay. Geometric mean titers of both vaccines displayed no significant difference at month 1, 6, and 7. Following the second dose of vaccine, the seroprotection titer (10 mIU/ml) rates at month 7 were 90.9% in HBV-NF and 93.4% in Engerix-B, respectively (p = 0.43). The incidences of local and general adverse reactions were from 3% to 7% without significant difference between the two vaccines and the reactions were all mild and tolerable. Based on this study, regimens of this two-dose schedule proved to be safe and immunogenic, which may provide a cost-effective alternative for HBV mass vaccination program in adolescents.

Exclusive homoplasmic 11778 mutation in mitochondrial DNA of Chinese patients with Leber's hereditary optic neuropathy

PURPOSE

To investigate the degree of heteroplasmy of the 11778 mtDNA mutation in Chinese patients with Leber's hereditary optic neuropathy (LHON).

METHODS

Seventeen Chinese Leber's pedigrees, including 24 patients, 17 unaffected maternal lineages, 4 internal controls, and 6 unrelated controls, were screened for the 11778 mtDNA mutation. This was carried out by analysis of the restriction fragment length polymorphism, single-strand conformation polymorphism, and DNA sequencing.

RESULTS

All patients and unaffected maternal lineages, regardless of their symptoms, had homoplastic 11778 mtDNA mutation, which was revealed by restriction fragment length polymorphism analysis and single-strand conformation polymorphism analysis.

CONCLUSION

Exclusive homoplasmy of the 11778 mtDNA mutation in Chinese LHON patients was found in this study. Homoplasmy of the 11778 mtDNA mutation cannot account for the variation in the clinical phenotype of Chinese Leber's patients.

Prenatal sonographic detection of adrenal hemorrhage confirmed by postnatal surgery

We report a case of adrenal hemorrhage in a newborn first detected by sonography at a menstrual age of 21 weeks 4 days. An echogenic mass was noted above the right kidney. The mass became larger and hypoechoic on follow-up sonograms after birth. The mass was also seen on abdominal CT. Because it was difficult to differentiate the lesion from cystic neuroblastoma and because it shrank only modestly by 2 months after birth, we performed a surgical exploration when the patient was 2 months old, and adrenal hemorrhage was confirmed. This case suggests that adrenal hemorrhage can occur as early as the second trimester of pregnancy.

Intermittent parathyroid hormone treatment can promote linear growth in the ovariectomized growing rat

To compare the effect of intermittent parathyroid hormone (PTH) treatment with that of estrogen treatment on epiphyseal growth in ovariectomized rats, 46 Sprague-Dawley female rats aged 9-10 weeks (about 200-220 g) were either ovariectomized or sham operated. From 6 weeks after ovariectomy (ovx), rats were daily injected with subcutaneous human recombinant PTH (1-84)-dosed 30 micrograms/kg (the low dose PTH-treated group) or 300 micrograms/kg (the high dose PTH-treated group), 17 beta-estradiol (the 17 beta-estradiol-treated group, 30 micrograms/kg) or vehicle (the ovx-alone group), 5 times a week for 4 weeks. The decalcified sections of the distal femoral epiphyseal plate were analyzed on light microscopy after H&E stain, and the lengths of the zones of proliferation, maturing and hypertrophic chondrocytes were measured. The length of the growth plate, the zone of proliferation and the zone of hypertrophic chondrocyte in the ovx-alone group were significantly shorter than those of the sham-operated group. The treatment of 17 beta-estradiol speeded up the differentiation of cells from proliferating chondrocytes to maturing and hypertrophic chondrocytes even though the length of the growth plate was comparable to that of the sham-operated group. Both low and high dose PTH treatments increased the length of the growth plate, and those lengths were comparable to that of the sham-operated group. The fractions of proliferating, maturing and hypertrophic zone in the low dose PTH-treated group were also comparable to those of the sham-operated group. However, high dose PTH treatment slowed down the differentiation of cells from proliferating chondrocytes to maturing and hypertrophic chondrocytes to a greater extent, and therefore the fraction of proliferating chondrocytes of the high dose PTH-treated group was larger than that of the low dose PTH-treated group (73.8 +/- 1.8 Vs 63.3 +/- 1.3%, p < 0.005). From these results, we showed that intermittent PTH treatment could promote linear growth in the ovariectomized growing rat. We propose that PTH may be an alternative drug candidate for promoting linear growth of long bones without the risk for early closure of the growth plate.

Chlamydomonas chloroplast ferrous hemoglobin. Heme pocket structure and reactions with ligands

We report the optical and resonance Raman spectral characterization of ferrous recombinant Chlamydomonas LI637 hemoglobin. We show that it is present in three pH-dependent equilibrium forms including a 4-coordinate species at acid pH, a 5-coordinate high spin species at neutral pH, and a 6-coordinate low spin species at alkaline pH. The proximal ligand to the heme is the imidazole group of a histidine. Kinetics of the reactions with ligands were determined by stopped-flow spectroscopy. At alkaline pH, combination with oxygen, nitric oxide, and carbon monoxide displays a kinetic behavior that is interpreted as being rate-limited by conversion of the 6-coordinate form to a reactive 5-coordinate form. At neutral pH, combination rates of the 5-coordinate form with oxygen and carbon monoxide were much faster (>10(7) microM-1 s-1). The dissociation rate constant measured for oxygen is among the slowest known, 0.014 s-1, and is independent of pH. Replacement of the tyrosine 63 (B10) by leucine or of the putative distal glutamine by glycine increases the dissociation rate constant 70- and 30-fold and increases the rate of autoxidation 20- and 90-fold, respectively. These results are consistent with at least two hydrogen bonds stabilizing the bound oxygen molecule, one from tyrosine B10 and the other from the distal glutamine. In addition, the high frequency (232 cm-1) of the iron-histidine bond suggests a structure that lacks any proximal strain thus contributing to high ligand affinity.

Structures and activities of cyclic ADP-ribose, NAADP and their metabolic enzymes

ADP-ribosyl cyclase and CD38 are multi-functional enzymes involved in calcium signaling. Both can cyclize NAD and its guanine analog, NGD, at two different sites of the purine ring, N1 and N7, respectively, to produce cyclic ADP-ribose (cADPR) and cyclic GDP-ribose, a fluorescent but inactive analog. Both enzymes can also catalyze the exchange of the nicotinamide group of NADP with nicotinic acid, producing yet another potent activator of Ca2+ mobilization, nicotinic acid adenine dinucleotide phosphate (NAADP). The Ca2+ release mechanism activated by NAADP is totally independent of cADPR and inositol trisphosphate indicating it is a novel and hitherto unknown Ca2+ signaling pathway. This article summarizes the current results on the structures and activities of cADPR, NAADP and the enzymes that catalyze their syntheses. A comprehensive model accounting for the novel multi-functionality of ADP-ribosyl cyclase and CD38 is presented.

Concurrent increase of oxidative DNA damage and lipid peroxidation together with mitochondrial DNA mutation in human lung tissues during aging--smoking enhances oxidative stress on the aged tissues

Although mutation of mitochondrial DNA (mtDNA) in human tissues has been established to associate with intrinsic aging, the impact of environmental factors on the formation and accumulation of mtDNA mutations and oxidative DNA damage in human tissues is poorly understood. We have investigated the levels of mtDNA with the 4977-bp deletion and A3243G point mutation, oxidative DNA damage (indicated by the formation of 8-hydroxy-2'-deoxyguanosine, 8-OH-dG), and lipid peroxides in lung tissues from smokers and nonsmokers of subjects of different ages. The results showed concurrent age-dependent increase of the 4977-bp deleted mtDNA (P < 0.001), 8-OH-dG (P < 0.05), and lipid peroxides (P < 0.05) in the human lung. In the group of subjects above 60 years old, smokers had more extensive DNA damage and lipid peroxidation than did the nonsmokers. However, the levels of mtDNA with the 4977-bp deletion and A3243G point mutation in the lung of smokers were not significantly different from those of the age-matched nonsmokers. Taken together, these results suggest that accumulation of mtDNA with the 4977-bp deletion together with oxidative DNA damage and lipid peroxides is associated with aging and that smoking enhances oxidative damage in human lung tissues.

The heme environment in barley hemoglobin

To elucidate the environment and ligand structure of the heme in barley hemoglobin (Hb), resonance Raman and electron paramagnetic resonance spectroscopic studies have been carried out. The heme is shown to have bis-imidazole coordination, and neither of the histidines has imidazolate character. Barley Hb has a unique heme environment as judged from the Fe-CO and C-O stretching frequencies in the CO complex. Two Fe-CO stretching modes are observed with frequencies at 534 and 493 cm-1, with relative intensities that are pH sensitive. The 534 cm-1 conformer shows a deuterium shift, indicating that the iron-bound CO is hydrogen-bonded, presumably to the distal histidine. A C-O stretching mode at 1924 cm-1 is assigned as being associated with the 534 cm-1 conformer. Evidence is presented that the high Fe-CO and low C-O stretching frequencies (534 and 1924 cm-1, respectively) arise from a short hydrogen bond between the distal histidine and the CO. The 493 cm-1 conformer arises from an open conformation of the heme pocket and becomes the dominant population under acidic conditions when the distal histidine moves away from the CO. Strong hydrogen bonding between the bound ligand and the distal histidine in the CO complex of barley Hb implies that a similar structure may occur in the oxy derivative, imparting a high stability to the bound oxygen. This stabilization is confirmed by the dramatic decrease in the oxygen dissociation rate compared with sperm whale myoglobin.

The validity of random urine specimen albumin measurement as a screening test for diabetic nephropathy

To assess the validity of urine albumin concentration (UAC) and the urine albumin:creatine ratio (UACR) in a random urine specimen (RUS) for screening diabetic nephropathy in Korea, a total of 105 ambulatory diabetes mellitus patients (male:female, 52:53), ages 40-75 years (median 59 years) collected 105 RUSs after completing a timed 24 hour urine collection. Albumin was measured by immunonephelometry. According to the timed urinary albumin excretion rate (UAER) measured in the 24 hour collection (criterion standard), samples were classified normoalbuminuric (UAER < 20 micrograms/min; n = 50), microalbuminuric (UAER 20-200 micrograms/min; n = 30), and macroalbuminuric (UAER > 200 micrograms/min; n = 25). The receiver operating characteristics (ROC) curve of UAC and UACR in a RUS for screening of microalbuminuria (normo- and microalbuminuric samples; n = 80) and macroalbuminuria (micro- and macroalbuminuric samples; n = 55) were plotted. Pearson's coefficients of correlation of 24 hour UAER vs. UAC and UACR were 0.81 and 0.75, respectively (P < 0.001). The point of intersection with a 100%-to-100% diagonal for microalbuminuria were as follows: 31.0 mg/l for UAC and 32.5 mg/g for UACR; for macroalbuminuria 181 mg/l for UAC and 287.3 mg/g for UACR. The sensitivity and specificity of the cut-off points for microalbuminuria were 77% and 82% for UAC and 77% and 92% for UACR. The sensitivity and specificity of the cut-off points for macroalbuminuria were 84% and 90% for UAC and 88% and 90% for UACR. In present study, no difference was observed when comparing the performance of UAC and UACR based on a statistical comparison by McNemar test. The repeated measurements of UAC and UACR in the same individual were statistically similar and were correlated with each other. Based on these results, albumin measurements (UAC and UACR) in a RUS were considered as a valid test for screening diabetic nephropathy.