Association of Streptococcus mutans Infection and Oral Developmental Nodules in Pre-dentate Infants

Since dental caries may present soon after tooth eruption, we hypothesized that colonization of Streptococcus mutans can occur in the predentate stages. In this study, we examined S. mutans colonization and its association with oral developmental nodules (Bohn's nodules) in 60 pre-term and 128 full-term, three-month-old infants. Overall, S. mutans was cultured from 30% (56/188) of the infants, and oral developmental nodules were noted in 55% (103/188). Compared with the pre-term, full-term infants showed a higher prevalence of S. mutans (34% vs. 20%, p < 0.02) as well as developmental nodules (61% vs. 42%, p < 0.05). In both groups, S. mutans was positively associated with numbers of developmental nodules in a dose-response relationship (p < 0,001), and with maternal salivary levels of the bacteria (p = 0.03). The permanence of S. mutans infection was confirmed by repeat saliva sampling at 6 months of age. Our results thus showed that many infants have already acquired S. mutans at 3 months of age, prior to tooth eruption.

Changes in non-22-kilodalton (kDa) isoforms of growth hormone (GH) after administration of 22-kDa recombinant human GH in trained adult males

GH is being used by elite athletes to enhance sporting performance. To examine the hypothesis that exogenous 22-kDa recombinant human GH (rhGH) administration could be detected through suppression of non-22-kDa isoforms of GH, we studied seventeen aerobically trained males (age, 26.9 +/- 1.5 yr) randomized to rhGH or placebo treatment (0.15 IU/kg/day for 1 week). Subjects were studied at rest and in response to exercise (cycle-ergometry at 65% of maximal work capacity for 20 min). Serum was assayed for total GH (Pharmacia IRMA and pituitary GH), 22-kDa GH (2 different 2-site monoclonal immunoassays), non-22-kDa GH (22-kDa GH-exclusion assay), 20-kDa GH, and immunofunctional GH. In the study, 3 h after the last dose of rhGH, total and 22-kDa GH concentrations were elevated, reflecting exogenous 22-kDa GH. Non-22-kDa and 20-kDa GH levels were suppressed. Regression of non-22-kDa or 20-kDa GH against total or 22-kDa GH produced clear separation of treatment groups. In identical exercise studies repeated between 24 and 96 h after cessation of treatment, the magnitude of the responses of all GH isoforms was suppressed (P < 0.01), but the relative proportions were similar to those before treatment. We conclude: 1) supraphysiological doses of rhGH in trained adult males suppressed exercise-stimulated endogenous circulating isoforms of GH for up to 4 days; 2) the dearest separation of treatment groups required the simultaneous presence of high exogenous 22-kDa GH and suppressed 20-kDa or non-22-kDa GH concentrations; and 3) these methods may prove useful in detecting rhGH abuse in athletes.

Intravenous cisplatin administration in sulphur-crested cockatoos (Cacatua galerita): Clinical and pathologic observations

The prevalence of neoplasia in birds is generally low; however, in some species of companion and aviary birds, the incidence is high and neoplasia is a common cause of death. Surgical excision or limb amputation has been performed as the therapeutic plan. Chemotherapy in the treatment of avian neoplasia is largely empirical and poorly documented. For example, cisplatin has been used intralesionally in macaws (Ara species) with limited clinical success. Eight sulphur-crested cockatoos (Cacatua galerita), under general isoflurane anesthesia, were infused intravenously with cisplatin at 6.4 or 1.0 mg/kg over 1 hour and hydrated with lactated Ringer's solution for 1 hour before and 2 hours after cisplatin infusion. Birds were euthanatized 96 hours after infusion, except for 2 birds given the low cisplatin dose, which were euthanatized on day 35 after dosing. All birds tolerated the study procedure while under anesthesia. Blood pressure, heart rate, and respiratory rate did not change significantly. In the low-dose group, the mean cloacal temperature decreased significantly during the infusion period (P < .001) and then rose progressively to preinfusion values by 24 hours. Also in this group, the mean body weight tended to increase during the infusion period before significantly decreasing (P < .05) by 5% at 96 hours after dosing. At 24 hours after dosing, all birds were bright and eating. However, intermittent regurgitation and fecal changes (moist, dark green feces and yellow urates) occurred in 3 of 8 birds, especially those given the high dose. By 72 hours after dosing, droppings in the low-dose group were normal in appearance. One bird in the high-dose group died by 94 hours after dosing. Myelosuppression was not observed in any bird and at necropsy, no evidence of cisplatin toxicity was found except in 1 bird given the high cisplatin dose. On histology, this bird showed nephrotoxicity, and its serum uric acid levels and mean estimated white blood cell count increased significantly by 24 hours after dosing. This paper reports for the first time the effect of systemic cisplatin administration in birds and provides veterinarians data for formulating efficacious and safe protocols for platinum-containing compounds when treating neoplasia in parrots and other companion birds.

beta-hydroxy-beta-methylbutyrate (HMB) supplementation does not affect changes in strength or body composition during resistance training in trained men

This investigation evaluated the effects of oral beta -Hydroxy-beta -Methylbutyrate (HMB) supplementation on training responses in resistance-trained male athletes who were randomly administered HMB in standard encapsulation (SH), HMB in time release capsule (TRH), or placebo (P) in a double-blind fashion. Subjects ingested 3 g (.) day(-1) of HMB; or placebo for 6 weeks. Tests were conducted pre-supplementation and following 3 and 6 weeks of supplementation. The testing battery assessed body mass, body composition (using dual energy x-ray absorptiometry), and 3-repetition maximum isoinertial strength, plus biochemical parameters, including markers of muscle damage and muscle protein turnover. While the training and dietary intervention of the investigation resulted in significant strength gains (p < .001) and an increase in total lean mass (p =.01), HMB administration had no influence on these variables. Likewise, biochemical markers of muscle protein turnover and muscle damage were also unaffected by HMB supplementation. The data indicate that 6 weeks of HMB supplementation in either SH or TRH form does not influence changes in strength and body composition in response to resistance training in strength-trained athletes.

Simultaneous administration of a cocktail of markers to measure renal drug elimination pathways: absence of a pharmacokinetic interaction between fluconazole and sinistrin, p-aminohippuric acid and pindolol

Aims Previous studies suggest that estimated creatinine clearance, the conventional measure of renal function, does not adequately reflect charges in renal drug handling in some patients, including the immunosuppressed. The aim of this study was to develop and validate a cocktail of markers. to be given in a single administration, capable of detecting alterations in the renal elimination pathways of glomerular filtration, tubular secretion and tubular reabsorption. Methods Healthy male subjects (n = 12) received intravenously infused 2500 mg sinistrin (glomerular filtration) and 440 mg p-aminohippuric acid (PAH; anion secretion), and orally administered 100 mg fluconazole (reabsorption) and 15 mg rac-pindolol (cation secretion). The potential interaction between these markers was investigated in a pharmacokinetic study where markers (M) or fluconazole (F) were administered alone or together (M + F). Validated analytical methods were used to measure plasma and urine concentrations in order to quantify the renal handling of each marker. Plasma protein binding of fluconazole was measured by ultrafiltration. All subjects had an estimated creatinine clearance within the normal range. The renal clearance of each marker (Mean +/- s.d.) was calculated as the ratio of the amount excreted in urine and thearea-under-the-concentration-time curve. Statistical comparisons were made using a paired t-test and 95% confidence intervals were reported. Results The renal clearances of sinistrin (M: 119 +/- 31 ml min(-1); M + F: 130 +/- 40 ml min(-1); P = 0.32), PAH (M: 469 +/- 145 ml min(-1); M + F: 467 +/- 146 ml min(-1); P = 0.95), R-pindolol (M: 204 +/- 41 ml min(-1); M + F: 190 +/- 41 ml min(-1); P = 0.39; n = 11), S-pindolol (M: 225 +/- 55 ml min(-1); M + F: 209 +/- 60 ml min(-1); P = 0.27; n = 11) and fluconazole (F: 14.9 +/-3.8 ml min(-1); M + F: 13.6 +/- 3.4 ml min(-1); P = 0.16) were similar when the markers or fluconazole were administered alone (M or F) or as a cocktail (M + F). Conclusions This study found no interaction between markers and fluconazole in healthy male subjects, suggesting that a single administration of this cocktail of markers of different renal processes call be used to simultaneously investigate pathways of renal drug elimination.

Gag-Pol supplied in trans is efficiently packaged and supports viral function in human immunodeficiency virus type 1

The intracellular trafficking and subsequent incorporation of Gag-Pol into human immunodeficiency virus type 1 (HIV-1) remains poorly defined. Gag-Pol is encoded by the same mRNA as Gag and is generated by ribosomal frameshifting. The multimerization of Gag and Gag-Pol is an essential step in the formation of infectious viral particles. In this study, we examined whether the interaction between Gag and Gag-Pol is initiated during protein translation in order to facilitate the trafficking and subsequent packaging of Gag-Pol into the virion. A conditional cotransfection system was developed in which virion formation required the coexpression of two HIV-1-based plasmids, one that produces both Gag and Gag-Pol and one that only produces Gag-Pol. The Gag-Pol proteins were either immunotagged with a His epitope or functionally tagged with a mutation (K65R) in reverse transcriptase that is associated with drug resistance. Gag-Pol packaging was assessed to determine whether the Gag-Pol incorporated into the virion was preferentially packaged from the plasmid that expressed both Gag and Gag-Pol or whether it could be packaged from either plasmid. Our data show that translation of Gag and Gag-Pol from the same mRNA is not critical for virion packaging of the Gag-Pol polyprotein or for viral function.

Early rise in blood pressure following administration of adrenocorticotropic hormone-[1-24] in humans

1. An elevation in blood pressure has been consistently observed 24 h after adrenocorticotropic hormone (ACTH) administration and is caused by increased ACTH-stimulated cortisol secretion, in association with increased cardiac output. The aim of the present study was to investigate the previously undefined time of onset of this increase in blood pressure in normal humans. 2. Ten normal healthy volunteers received 250 mug ACTH-[1-24], in 500 mL normal saline, infused at a constant rate over 8 h. Six subjects also received a placebo infusion (normal saline only). Blood pressure, heart rate and cortisol levels were determined hourly. Adrenocorticotropic hormone (ACTH-[1-24] plus native ACTH) was measured at 0, 1, 7 and 8 h. 3. Infusion of ACTH-[1-24] produced maximal secretion rates of cortisol, resulting in a mean peak plasma level of 985 +/- 46 nmol/L at 8 h. In response, blood pressure and heart rate rose significantly by 2 h and remained generally elevated for the duration of the infusion. 4. The early onset of haemodynamic responses is consistent with classical steroid receptor-mediated genomic mechanisms, but could be due non-genomic mechanisms. 5. The cardiovascular consequences of therapeutic use of ACTH are well recognized. This results of the present study suggest that even diagnostic administration of ACTH, delivered over a few hours, may raise blood pressure.

Pre- and postsynaptic actions of ATP on neurotransmission in rat submandibular ganglia

The pre- and postsynaptic actions of exogenously applied ATP were investigated in intact and dissociated parasympathetic neurotics of rat submandibular ganglia. Nerve-evoked excitatory postsynaptic potentials (EPSPs) were not inhibited by the purinergic receptor antagonists, suramin and pyridoxal-phosphate-6-azophenyl-2 ' ,4 ' -disulphonic acid (PPADS), or the desensitising agonist, alpha,beta -methylene ATP. In contrast. EPSPs were abolished by the nicotinic acetylcholine receptor antagonists, hexamethonium and mecamylamine. Focal application of ATP (100 muM) had no effect on membrane potential of the postsynaptic neurone or on the amplitude of spontaneous EPSPs. Taken together, these results suggest the absence of functional purinergic (P2) receptors on the postganglionic neurone in situ. In contrast, focally applied ATP (100 muM) reversibly inhibited nerve-evoked EPSPs. Similarly, bath application of the non-hydrolysable analogue of ATP, ATP gammaS, reversibly depressed EPSPs amplitude, The inhibitory effects of ATP and ATP gammaS on nerve-evoked transmitter release were antagonised by bath application of either PPADS or suramin, suggesting ATP activates a presynaptic P2 purinoceptor to inhibit acetylcholine release from preganglionic nerves in the submandibular ganglia. In acutely dissociated postganglionic neurotics from rat submandibular ganglia. focal application of ATP (100 LM) evoked an inward current and subsequent excitatory response and action potential firing, which was reversibly inhibited by PPADS (10 muM). The expression of P2X purinoceptors in wholemount and dissociated submandibular ganglion neurones was examined using polyclonal antibodies raised against the extracellular domain of six P2X purinoceptor subtypes (P2X(1-6)). In intact wholemount preparations, only the P2X(5) purinoceptor subtype was found to be expressed in the submandibular ganglion neurones and no P2X immunoreactivity was detected in the nerve fibres innervating the ganglion. Surprisingly, in dissociated submandibular ganglion neurones, high levels of P2X(2) and P2X(4) purinoceptors immunoreactivity were found on the cell surface. This increase in expression of P2X(2) and P2X(4) purinoceptors in dissociated submandibular neurones could explain the increased responsiveness of the neurotics to exogenous ATP. We conclude that disruption of ganglionic transmission in vivo by either nerve damage or synaptic blockade may up-regulate P2X expression or availability and alter neuronal excitability. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.

Route of administration of chimeric BPV1VLP determines the character of the induced immune responses

To examine the mucosal immune response to papillomavirus virus-like particles (PV-VLP), mice were immunized with VLP intrarectally (i.r.), intravaginally (i.va.) or intramuscularly (i.m.) without adjuvant. PV-VLP were assembled with chimeric BPV-1 L1 proteins incorporating sequence from HIV-1 gp 120, either the V3 loop or a shorter peptide incorporating a known CTL epitope (HIVP18I10). Antibody specific for BPV-1 VLP and P18 peptide was detected in serum following i.m., but not i.r. or i.va. immunization. Denatured VLP induced a much reduced immune response when compared with native VLP, Immune responses following mucosal administration of VLP were generally weaker than following systemic administration. VLP specific IgA was higher in intestine washes following i.r. than i.va. immunization, and higher in vaginal washes following i.m. than i.r. or i.va. immunization. No differences in specific antibody responses were seen between animals immunized with BPV-1 P18 VLP or with BPV-1 V3 VLP. Cytotoxic T lymphocyte precursors specific for the P18 CTL epitope were recovered from the spleen following i.m., i.va. or i.r. immunization with P18 VLP, and were similarly detected in Peyer's patches following i.m. or i.r. immunization. Thus, mucosal or systemic immunization with PV VLP induces mucosal CTL responses and this may be important for vaccines for mucosal infection with human papillomaviruses and for other viruses.