Synthesis and antimicrobial applications of 5,5'-ethylenebis[5-methyl-3-(3-triethoxysilylpropyl)hydantoin].

A novel, durable, long lasting, N-halamine siloxane monomer precursor, 5,5'-ethylenebis[5-methyl-3-(3-triethoxysilylpropyl)hydantoin] has been prepared and characterized by (1)H-NMR and FTIR for the purpose of functionalizing the surfaces of various materials. In this work, the precursor N-halamine moiety was attached by siloxane covalent bonding to surfaces of cotton fibers. Simulated laundering tests indicated that the chlorinated N-halamine structure could survive many repeated home launderings. The materials were rendered biocidal after exposure to oxidative halogen solutions, i.e. dilute household bleach. Once chlorinated, these materials were biocidal against Staphylococcus aureus and Escherichia coli. Upon loss of the halogen from either long-term use or consumption by the microbes on the surfaces, they could be simply recharged by further exposure to dilute bleach to regain biocidal activity.

An atypical iron-responsive element (IRE) within crayfish ferritin mRNA and an iron regulatory protein 1 (IRP1)-like protein from crayfish hepatopancreas.

A putative crayfish iron-responsive element (IRE) is present in the 5'-untranslated region of the crayfish ferritin mRNA. The putative crayfish IRE is in a cap-proximal position and shares most of the structural features of the consensus IRE, but the RNA stem-loop structure contains a bulge of a guanine instead of a cytosine at the expected position, so far thought to be a hallmark of IREs. By using an electromobility shift assay this IRE was shown to specifically bind purified recombinant human iron regulatory protein 1 (IRP1) as well as a factor(s) present in a homogenate of crayfish hepatopancreas, likely to be a crayfish IRP1 homologue. With mutations in the crayfish IRE, the affinity of IRP to IRE was drastically decreased. A cDNA encoding an IRP1-like protein was cloned from the hepatopancreas of crayfish. This protein has sequence similarities to IRP, and contains all the active-site residues of aconitase, two putative RNA-binding regions and a putative contact site between RNA and IRP. These results show that a crayfish IRE, lacking the bulged C, can bind IRP1 in vitro and that an IRP1-like protein present in crayfish hepatopancreas may have both aconitase and RNA-binding activities.

Purification and cDNA cloning of ferritin from the hepatopancreas of the freshwater crayfish Pacifastacus leniusculus.

Ferritin was purified from the hepatopancreas of the freshwater crayfish Pacifastacus leniusculus after injection of iron. It has the same size as horse spleen ferritin (440 kDa) and migrates as two bands, 19 kDa and 20 kDa, respectively, in SDS/PAGE under reducing conditions. Crayfish ferritin (20 kDa) was cloned from a hepatopancreas cDNA library. The deduced amino acid sequence of the crayfish ferritin shows a closer relationship to vertebrate ferritin heavy chains than to insect ferritin and contains the conserved H-specific residues for the ferroxidase centre found in vertebrate ferritin heavy chain. An IRE(iron-responsive element)-like sequence with a predicted stem-loop structure was present in the 5' untranslated region of the crayfish ferritin mRNA. Crayfish ferritin does not share the atypical properties of insect ferritins, such as high molecular mass of intact protein, abundance in hemolymph, and export into vacuoles. We suggest that there are two different types of ferritins distributed in different species: insect-type or secretory ferritins which are predominant in the snail oocyte and insects, and vertebrate (crustacean)-type or cytosolic ferritins which are predominant in vertebrates and crustacea.

Changes of bone markers during long-term intravenous calcitriol therapy in maintenance dialysis patients.

Twenty patients with end-stage renal failure on maintenance hemodialysis were studied for the effect of intravenous 1,25(OH)2 vitamin D3 on biochemical bone markers. Active vitamin D, 1,25(OH)2 vitamin D3, was given intravenously after hemodialysis, 1 microgram thrice weekly. Serum ionized calcium, phosphorus, alkaline phosphatase (AKPase), intact parathyroid hormone (PTH), osteocalcin (bone Gla protein), carboxy terminal propeptide of type I procollagen (PICP), cross-linked telopeptide of type I collagen (ICTP) and beta 2-microglobulin were measured before and after 3 and 6 months of treatment with 1,25(OH)2 vitamin D3. The serum ionized calcium and osteocalcin levels were significantly increased at 3 and 6 months after treatment. The serum beta 2-microglobulin level were also increased 6 months after treatment, whereas the serum levels of AKPase and intact PTH decreased after treatment. However, the serum levels of phosphorus, PICP and ICTP did not change significantly after treatment. The decreased levels of serum AKPase and intact PTH suggest reduced bone resorption. Increases of serum osteocalcin levels were caused by stimulation of the osteoblast by 1,25(OH)2 vitamin D3, baseline 20.6 +/- 12.5 micrograms/l, and 36.1 +/- 34.0 and 31.0 +/- 24.6 micrograms/l at 3 and 6 months, respectively (p < 0.01). The lower osteocalcin level at 6 rather than at 3 months may imply reduced bone resorption and/or increased bone mineralization. The meaning of the increase of serum beta 2-microglobulin in uremic patients after calcitriol treatment is unclear. It may indicate reduced deposition and is masked by increased bone resorption from secondary or tertiary hyperparathyroidism. This study did not validate PICP and ICTP measurements as bone markers in uremic patients.

Effect of triiodothyronine administration in experimental myocardial injury.

Twelve healthy pigs were subjected to a 20-min, period of regional myocardial ischemia by snaring the left anterior descending coronary artery (LAD) between its first and second diagonal branches. The resulting myocardial injury caused significant acute hemodynamic impairments. Cardiac index declined significantly during reperfusion interval and returned to preischemic level by postoperative day 7. Plasma total triiodothyronine (TT3), free triiodothyronine (FT3) and free fatty acid (FFA) decreased gradually and reached the nadir at 6 h after LAD occlusion. In contrast, plasma reverse triiodothyronine (rT3) increased progressively after LAD occlusion and reperfusion. To investigate the effect of T3 on ischemic myocardium, T3 (0.2 microgram/kg/dose; n = 5) or saline (placebo; n = 6) was administered immediately, 30 min, 60 min, 90 min, and 120 min after reperfusion. Plasma TT3 and FT3 increased dramatically after triiodothyronine supplement but declined to presichemic level at six h after LAD occlusion. The pigs treated with T3 demonstrated a rapid improvement in cardiac index over the reperfusion interval, whereas cardiac index in the placebo group remained depressed. Myocardial oxygen consumption estimated by rate pressure product showed no difference between placebo and T3-treated groups. Oxygen extraction as O2 saturation difference between aorta and coronary sinus was less in T3-treated group. Nine pigs (four in the T3-treated group and five in the placebo group) were subjected to euthanasia with hypertonic KCl solution on postoperative day 7. Myocardial infarct size determined by triphenyltetrazolium chloride (TTC) tissue enzyme staining technique was not significantly different between T3-treated and placebo groups. We concluded that this animal model is a useful model of myocardial injury simulating "euthyroid sick syndrome" as seen in patients with cardiopulmonary bypass, and T3 supplementation after reperfusion significantly enhanced postischemic left ventricular functional recovery but did not affect myocardial oxygen consumption and myocardial infarct size.

Suppression of the hypothalamus-pituitary somatotrope axis in men with spinal cord injuries.

Thirty-two men with spinal cord injury (SCI) were studied for evaluation of the hypothalamus-pituitary somatotrope axis, using growth hormone-(GH)-releasing hormone (GHRH) and insulin-induced hypoglycemia. Twenty-six age-matched normal male volunteers served as controls. Six SCI subjects (18.7%) had elevated basal follicle-stimulating hormone (FSH) levels, eight (25.0%) had hyperprolactinemia, and 11 (34.4%) had reduced serum insulin-like growth factor-1 (IGF-1) levels. Twenty SCI subjects (62.5%) had reduced and/or delayed GH responses to GHRH, and eight (25.8%) had reduced GH response to insulin-induced hypoglycemia. Seven of eight hyperprolactinemic SCI subjects showed reduced GH response to GHRH and/or insulin-induced hypoglycemia. These findings are consistent with the notion that SCI subjects have a reduced central dopaminergic tone.

cDNA cloning of prophenoloxidase from the freshwater crayfish Pacifastacus leniusculus and its activation.

Prophenoloxidase (proPO), an enzyme that is the terminal component of the so-called proPO activating system, a defense and recognition system in crustaceans and insects, has been purified and cloned from a crayfish blood cell cDNA library. The deduced amino acid sequence codes for a polypeptide with a mass of 80,732 Da, which is close to 76 kDa, the apparent mass of the purified enzyme. proPO contains two copper atoms, and two putative copper-binding sites were found in the deduced amino acid sequence. Sequence comparisons show that these putative copper-binding sites are similar to the corresponding sites in arthropod hemocyanins and also, although the sequence similarities are less extensive, similar to tyrosinases from vertebrates and microorganisms. The purified enzyme is a typical tyrosinase because it hydroxylates monophenols and oxidizes o-diphenols but does not oxidize p-diphenols. If a homogeneous preparation of crayfish proPO were incubated with a homogeneous sample of the proPO activating enzyme, a serine proteinase, the cleavage of proPO by this trypsin-like enzyme was found to occur between Arg-176 and Thr-177.

Reversion of the transformed phenotypes of v-H-ras NIH3T3 cells by flavonoids through attenuating the content of phosphotyrosine.

Fifteen flavonoids were employed to examine their effects on the morphological changes, foci formation in soft agar and cellular growth in v-H-ras-transformed NIH3T3 cells. The data presented here demonstrated that only three specific flavonoids--apigenin, kaempferol, and genistein--exhibited the reverting effect on the transformed phenotypes of ras-3T3 cells. For example, treatment with 25 microM of these flavonoids could effectively reverse the transformed morphology of ras-3T3 cells into flatter cells with contact inhibition. Colony formation in soft agar was decreased to 0.11%, 0.15%, and 0.35% by 25 microM apigenin, kaempferol, and genistein, respectively, as compared with control (0.92%). It was also found that the proliferation of ras-3T3 cells was significantly inhibited by these compounds in a dose-dependent manner. Finally, two biochemical parameters, the content of phosphotyrosine and cAMP, were examined to see whether affected by these compounds. The results showed the phosphotyrosine content in ras-3T3 cells was dramatically decreased by apigenin and kaempferol, but that was slightly reduced by genistein. By contrast, these three flavonoids all failed to significantly alter the level of cAMP within this transformant. Based on these observations, we suggest that some specific flavonoids are capable of reverting the transforming properties of v-H-ras transformed cells. The possible mechanism of this reversion is not mediated by activating the protein kinase A or its associated pathways, but rather inhibiting tyrosine kinases, subsequently leading to the blockage of p21ras-mediated signal transduction circuitry.

Effect of humic acids on thyroidal function.

Humic substances (HS) have been implicated as environmental goitrogens. Increased prevalence of goiter has been recently noticed in the blackfoot disease endemic area on the southwest coast of Taiwan, where well water is rich in HS. This study investigated the in vivo effects of humic acids (HA) on the thyroid gland of rats and mice. Groups of mice and rats were fed regular or moderately iodine deficient (approximately 167 vs 700 micrograms l- per kg) chow and distilled water or HA water (1mg/ml) for 3 or 4 months. Serum T4, T3, reverse T3, and/or TSH were measured by radioimmunoassay. Thyroidal 125I uptake was measured in mice at 2 h after injection of 1 microCi125I ip. Treatment of the rat with HA was associated with a significantly (p < 0.05) reduced serum T4 without a change in other parameters of study. Treatment with low iodine diet was associated with a clear increase in serum T3 and a decrease in serum rT3. Rats treated with both HA and low iodine diet showed a significantly reduced serum T4, increased serum T3 and decreased serum rT3. In mice, treatment with low iodine diet significantly increased thyroidal 125I uptake and additional treatment with HA significantly enhanced the effect of low iodine diet. Treatment with HA did not influence thyroid weight of rats or mice given normal or iodine deficient diets. We conclude that HA per se do not induce goiter, but they may enhance the goitrogenic effect of low iodine.

Corticotropin secretagogues facilitate recovery of the hypothalamus-pituitary-adrenal axis suppressed by prolonged treatment with dexamethasone.

Prolonged use of glucocorticoids (GCs) can cause prolonged suppression of the hypothalamus-pituitary-adrenal (HPA) axis. This study examined the possibility that corticotropin or its secretagogues such as vasopressin, corticotropin-releasing hormone (CRH), or insulin accelerate recovery of the HPA axis after prolonged treatment with dexamethasone (DEX). Suppression of the HPA axis was induced in rats by DEX at a dosage of 250 micrograms/100 g body weight (BW)/d for 14 days, after which rats were administered saline, corticotropin (Cortrosyn 0.1 mg), ovine CRH (oCRH 6 micrograms), vasopressin (2 U), or insulin (2 U) each morning. Adrenal weight (AW), BW, plasma corticosterone, and corticotropin, as well as pituitary corticotropin content, decreased significantly after DEX treatment. The plasma corticotropin level was significantly elevated 7 days after discontinuation of DEX treatment (day 8) and remained so until day 11, whereas the pituitary corticotropin content had returned to normal on day 8. Plasma corticosterone was suppressed until day 8, but was not significantly different from normal on day 11. The AW was also decreased until day 4, but was not different from normal on day 8 or day 11. The BW of experimental rats remained subnormal during the study period. Treatment of DEX-suppressed rats with exogenous corticotropin induced adrenal hyperplasia, but suppressed the plasma corticotropin level and delayed the normalization of plasma corticosterone until day 11. The insulin-treated group differed in no respect from the saline-treated group. Treatment with oCRH or vasopressin for 8 days normalized plasma and pituitary corticotropin, as well as plasma corticosterone. Hypothalamic immunoreactive CRH (iCRH) did not differ among any treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduced hypothalamic blood flow after radiation treatment of nasopharyngeal cancer: SPECT studies in 34 patients.

To determine the effect of cranial irradiation on hypothalamic blood flow, we performed 44 regional cerebral blood flow studies with 99mTc hexamethyl propyleneamine oxime (HMPAO) single-photon emission CT (SPECT) on four normal volunteers and 34 patients with pathologically proved nasopharyngeal cancer. Twenty-three men and 15 women, 30-65 years old, were divided into four study groups: group 1 served as a control and consisted of four normal volunteers and six patients studied prior to cranial irradiation; group 2 patients had cranial irradiation half a year before the SPECT study (n = 12, one from group 1); group 3 patients were irradiated 1 year before the study (n = 13, three from group 1 and two from group 2); and group 4 patients were irradiated at least 5 years before SPECT imaging (n = 9). Six patients were studied twice. Quantification of the 99mTc-HMPAO brain SPECT studies was done separately by three radiologists to obtain the hypothalamus/occipital (H/O) and hypothalamus/parasagittal (H/P) ratios. Endocrinologic studies were performed in all cases and the hypothalamus-thyrotroph-thyroid, hypothalamus-gonadotroph-testis (ovary), hypothalamus-lactotroph, hypothalamus-somatotroph, and hypothalamus-corticotroph-adrenal axes were evaluated separately. We determined that regional hypothalamic blood flow was reduced after cranial irradiation in patients with nasopharyngeal cancer. The H/O ratio of groups 3 and 4 did not differ from that of group 2 (one-half year after cranial irradiation). The H/O ratio was significantly reduced 6 months and 1 year after cranial irradiation; mean +/- SD = 0.5801 +/- 0.0829 (p less than .025), 0.5725 +/- 0.0791 (p less than .01) versus 0.6477 +/- 0.0458 before cranial irradiation, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of cranial irradiation on hypothalamus and pituitary functions.

Hypopituitarism can occur after cranial irradiation for tumors distant from the pituitary gland. Recent studies have suggested that this is hypothalamic in origin. Hypothalamic and pituitary functions were studied in 11 patients, 4 men and 7 women, 4.5 years or more after radiotherapy for nasopharyngeal carcinomas. The estimated average total dose was 5000 cGys for the hypothalamus and pituitary gland. Except for 2 women with amenorrhea and 4 men with impotency, the patients did not have evident endocrine deficiency. Baseline hormone profiles revealed normal T4, T3 and cortisol levels, 6 with elevated prolactin, 3 with reduced testosterone and 3 with slightly elevated basal TSH. The four menopausal women had impaired gonadotropin response to LHRH (100 micrograms, i.v.). Four (1 menstruating, 1 amenorrheic, 2 menopausal) women did not reach peak FSH response 4 hours after LHRH injection. The other amenorrheic woman had minimal FSH and LH response to LHRH which persisted even after 8 days of pulsatile infusion of LHRH (1 microgram/90min). TSH response to TRH (400 micrograms, i.v.) was delayed in 7 patients. GH response to human GRH (1 microgram/kg, i.v.) was impaired in 6 patients (maximal GH less than 5 mU/l). ACTH response to ovine CRH (1 microgram/kg, i.v.) was impaired in 3 patients (less than 50% elevation from baseline). Three patients who had normal GRH tests had impaired GH response to insulin hypoglycemia. Six patients had an empty sella on CT scan. From this study the following conclusions are drawn: (1) Among the four axes, GH is the most vulnerable. (2) The insulin tolerance test is still the best single test for evaluation of hypothalamic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Current clinical results of the cochlear implant program conducted on Mandarin-speaking patients.

This paper reports preliminary results from the 3M/HEI cochlear implant program conducted on oriental adult patients who speak Mandarin-Chinese. The whole program was performed according to the trained experience and the specific manuals provided by the House Ear Institute. Various testing and training materials (Chinese version of the monosyllable-trochee-spondee [MTS] test) as well as modified candidate evaluation procedures and criteria were applied. Three patients were considered as appropriate candidates. The third patient did not respond to the electrostimulation and is waiting for revision surgery. The warble-tone and speech detection thresholds aided with the implant devices of the first two patients were comparable with those found in western cases. Obvious improvements over the performance of stress discrimination on the MTS test were also noted. The tasks of speechreading, voice monitoring, and use of emergency telephone code were much easier for the first patient. Both patients indicated ability to detect and recognize many environmental sounds. Audiology-oriented findings, testing experiences, and suggestions for the program are presented and discussed. It is hoped that this paper will be helpful for the field and for similar programs in other countries.