Systemic and Myocardial Oxygen Transport Responses to Brain Death in Pigs

BACKGROUND

Brain death is associated with profound disturbances of systemic and myocardial oxygen transport, but little is known regarding the acute response of systemic oxygen consumption (VO(2)).

METHODS

Brain death was induced in 6 pigs (30.6 +/- 3.0 kg) by balloon inflation into the cranial cavity. VO(2) was continuously measured by respiratory mass spectrometry. Blood pressures and gases were measured from the aorta, superior vena cava, and coronary sinus, with arterial epinephrine and norepinephrine, prior to brain death, at 1, 10, and 90 minutes after brain death. Cardiac output (CO), systemic vascular resistance (SVR), oxygen delivery (DO(2)), oxygen extraction (EO(2)), and myocardial oxygen (mEO(2)) and lactate extractions (mE(1ac)) were calculated. Left ventricular contractility was assessed by micromanometer tipped catheters.

RESULTS

VO(2) increased from 4.8 +/- 0.9 to 6.3 +/- 0.9 mL/min/kg 1 minute after brain death (P < .001), and subsequently decreased to below baseline at 90 minutes (P < .001). Left ventricular contractility, CO, and DO(2) increased 1 minute after brain death (P < .001), followed by a rapid decrease to baseline within 10 minutes (P < .001). SVR and EO(2) decreased after brain death (P < .01) and remained low. Lactate remained unchanged. mE(1ac) decreased after brain death despite a decrease in mEO(2) (P < .01), and returned to baseline at 90 minutes.

CONCLUSIONS

The initial surge in VO(2) after brain death is offset by the greater increase in DO(2), thus tissue perfusion remains adequate. The lower than baseline VO(2) and SVR at the end of the study period may indicate general metabolic and hemodynamic compromise. The information regarding the profound metabolic alterations imposed by brain death may have implications for management of brain death donors.

The discovery of tetrahydrofluorenones as a new class of estrogen receptor beta-subtype selective ligands

Synthesis and derivatization of a series of substituted tetrahydrofluorenone analogs giving potent, ERbeta subtype selective ligands are described. Several analogs possessing ERbeta binding affinities comparable to 17beta-estradiol but with greater than 75-fold selectivity over ERalpha are reported.

Assessment of the relationship between cerebral and splanchnic oxygen saturations measured by near-infrared spectroscopy and direct measurements of systemic haemodynamic variables and oxygen transport after the Norwood procedure

OBJECTIVES

To evaluate the clinical utility of near-infrared spectroscopic (NIRS) monitoring of cerebral (ScO2) and splanchnic (SsO2) oxygen saturations for estimation of systemic oxygen transport after the Norwood procedure.

METHODS

ScO2 and SsO2 were measured with NIRS cerebral and thoracolumbar probes (in humans). Respiratory mass spectrometry was used to measure systemic oxygen consumption (O2). Arterial (SaO2), superior vena caval (SvO2) and pulmonary venous oxygen saturations were measured at 2 to 4 h intervals to derive pulmonary (Qp) and systemic blood flow (Qs), systemic oxygen delivery (DO2) and oxygen extraction ratio (ERO2). Mixed linear regression was used to test correlations. A study of 7 pigs after cardiopulmonary bypass (study 1) was followed by a study of 11 children after the Norwood procedure (study 2).

RESULTS

Study 1. ScO2 moderately correlated with SvO2, mean arterial pressure, Qs, DO2 and ERO2 (slope 0.30, 0.64. 2.30, 0.017 and -32.5, p < 0.0001) but not with SaO2, arterial oxygen pressure (PaO2), haemoglobin and O2. Study 2. ScO2 correlated well with SvO2, SaO2, PaO2 and mean arterial pressure (slope 0.43, 0.61, 0.99 and 0.52, p < 0.0001) but not with haemoglobin (slope 0.24, p > 0.05). ScO2 correlated weakly with O2 (slope -0.07, p = 0.05) and moderately with Qs, DO2 and ERO2 (slope 3.2, 0.03, -33.2, p < 0.0001). SsO2 showed similar but weaker correlations.

CONCLUSIONS

ScO2 and SsO2 may reflect the influence of haemodynamic variables and oxygen transport after the Norwood procedure. However, the interpretation of NIRS data, in terms of both absolute values and trends, is difficult to rely on clinically.

Comparative studies on the roles of mediator molecules in expression of the suppressor activity of Mycobacterium avium complex-induced immunosuppressive macrophages against T cell and B cell mitogenic responses

Mycobacterium avium complex-induced immunosuppressive macrophages (MAC-MPhis) exhibit suppressor activity against concanavalin A-induced T cell mitogenesis (T cell Con A mitogenesis). We examined the profiles of the MAC-MPhi-mediated suppression of lipopolysaccharide-induced B cell mitogenesis (B cell LPS mitogenesis) and found the following. First, although N(G)-monomethyl-L-arginine and carboxy-PTIO effectively blocked the MAC-MPhi's suppressor activity against T cell Con A mitogenesis, MAC-MPhi's action against B cell LPS mitogenesis was only weakly affected by these NO-reducing agents. Second, B cell LPS mitogenesis was remarkably more susceptible to MAC-MPhi-derived reactive oxygen intermediates than T cell Con A mitogenesis. Third, B cell LPS mitogenesis was less susceptible to the inhibitory effects of the other MAC-MPhi-derived suppressor mediators, including free fatty acids, TGF-beta and prostaglandin E(2), than T cell Con A mitogenesis. Fourth, MAC-MPhi's suppressor activity was strongly dependent on B7-1 like molecule-mediated cell contact with target cells only in the case of T cell Con A mitogenesis. Therefore, there are significant differences in the modes of suppressor action of MAC-MPhis against T cell and B cell mitogenesis.

Targeted nNOS gene transfer into the cardiac vagus rapidly increases parasympathetic function in the pig

Nitric oxide (NO) derived from neuronal nitric oxide synthase (nNOS) facilitates cardiac vagal neurotransmission and bradycardia in vitro. Here we provide evidence of rapid (within 9 h) protein expression and increased vagal responsiveness in vivo following targeted gene transfer of nNOS into the cardiac vagus of the pig. Right vagi were injected with vector encoding nNOS (Ad.nNOS) or saline, while left vagi received an injection of vector encoding enhanced green fluorescent protein (Ad.eGFP). Enhanced nNOS protein expression was detected exclusively in the right vagus nerve, with no evidence of iNOS expression. This was associated with increased baroreflex sensitivity and greater heart rate responsiveness to right vagal stimulation. In contrast, responsiveness of left vagi, or sham-injected right vagi remained constant over the same time period. Basal heart rate was unchanged following gene transfer, suggesting no change in vagal tone. These results support the pre-/post-ganglionic synapse as a site for NO-mediated facilitation of vagal bradycardia in the pig. In addition they demonstrate in vivo that functional gene expression induced with adenoviral vectors occurs earlier than first thought, and may therefore, provide a novel intervention to acutely modulate the neural control of cardiac excitability.

Endothelial nitric oxide synthase dysfunction in diabetic mice: importance of tetrahydrobiopterin in eNOS dimerisation

AIMS/HYPOTHESIS

Impaired nitric oxide (NO) bioactivity and increased superoxide (SO) production are characteristics of vascular endothelial dysfunction in diabetes. The underlying mechanisms remain unknown. In this regard, we investigated the role of tetrahydrobiopterin (BH4) bioavailability in regulating endothelial nitric oxide synthase (eNOS) activity, dimerisation and SO production in streptozotocin-induced diabetic mice.

METHODS

Mouse aortas were used for assays of the following: (1) aortic function by isometric tension; (2) NO by electronic paramagnetic resonance; (3) SO by lucigenin-enhanced chemiluminescence and dihydroethidine fluorescence; (4) total biopterin and BH4 by high-performance liquid chromatography; and (5) eNOS protein expression and dimerisation by immunoblotting.

RESULTS

In diabetic mouse aortas, relaxations to acetylcholine and NO levels were significantly decreased, but SO production was increased, in association with reductions in total biopterins and BH4. Although total eNOS levels were increased in diabetes, the protein mainly existed in monomeric form. Conversely, specifically augmented BH4 in diabetic endothelium preserved eNOS dimerisation, but the expression remained unchanged.

CONCLUSIONS/INTERPRETATION

Our results demonstrate that BH4 plays an important role in regulating eNOS activity and its functional protein structure, suggesting that increasing endothelial BH4 and/or protecting it from oxidation may be a rational therapeutic strategy to restore eNOS function in diabetes.

Effect of endodontic procedures on enterococci, enteric bacteria and yeasts in primary endodontic infections

AIM

To detect enterococci, enteric bacteria and yeast species from the canals of teeth with primary endodontic infections before and after canal preparation and to test the antibiotic susceptibility of enterococcal strains isolated from infected root canals.

METHODOLOGY

Twenty-five single-rooted teeth with pulp necrosis, intact pulp chambers and periradicular lesions were selected for study. Samples were collected from canals before and after instrumentation. Amongst isolated microorganisms from infected root canals only enterococci, enteric bacteria and yeasts were identified by biochemical tests. The in vitro antimicrobial susceptibility of isolated enterococci strains was evaluated by the Etest system.

RESULTS

Microorganisms were isolated from 92% of the samples following intracoronal access, 22% were enterococci, enteric bacteria or yeast species. After biomechanical preparation, these species were no longer detected. After 7 days without intracanal dressing, 100% of the canals contained microorganisms, 52% of which were target species. However, after using paramonochlorophenol [PRP (2.0 g), Rinosoro and polyethylene glycol (400 equal parts up to 100 mL)] as an intracanal dressing for 7 days, enteric bacteria and yeasts were not detected; only enterococci were still present. All strains of enterococci were susceptible to ampicillin, but exhibited variable susceptibility to rifampin and ciprofloxacin.

CONCLUSIONS

Enterococci, enteric bacteria and yeasts were present in primary endodontic infections. Enterococci, particularly Enterococcus faecalis and E. faecium were resistant to removal by root canal preparation followed by intracanal dressing.

In vitro antimicrobial effect of bacteriophages on human dentin infected with Enterococcus faecalis ATCC 29212

This study assessed the effect of bacteriophages on the viability of Enterococcus faecalis. Human dental roots were inoculated with a suspension of E. faecalis at three different multiplicities of infection - 0.1, 1.0 and 10.0. The phage lysate was able to significantly inhibit bacteria growth when incubated at the multiplicities of infection of 1.0, 10.0 and 0.1. The dental roots were also inoculated with bacteria for 6 days to allow bacterial penetration into the teeth tubules. Addition of the phage lysate to the roots following the 6-day incubation period led to a substantial reduction in bacteria viability. Phage therapy may be an important alternative for the treatment of root canal infections refractory to conventional endodontic therapy.

[Effect and mechanism of alpha1-adrenoceptor blocker combined with antibiotics for chronic prostatitis]

OBJECTIVE

To investigate the effect and mechanism of alpha1-adrenoceptor blocker combined with antibiotics in the treatment of chronic prostatitis.

METHODS

Eighty patients with chronic prostatitis were divided into two groups, one treated with alpha1-adrenoceptor blocker (Terazosin 2 mg qn) and Levo-ofloxacin (0.2 bid), and the other given Levo-ofloxacin (0.2 bid) alone for 6 weeks. Chronic prostatitis symptom index (CPSI), urodynamic data and prostatic secretion examination were compared before and after treatment.

RESULTS

The CPSI score of the treated group decreased from 31.8 +/- 7.4 to 15.5 +/-6.6, while that of the control group decreased from 30.9 +/- 7.1 to 21.4 +/- 6.2. There was significant difference between the two groups (P < 0.05). The maximum flow rates before and after the combined treatment were 16.5 +/- 6.3 ml/s and 20.4 +/- 4.6 ml/s, while those before and after Levo-ofloxacin administration were 16.1 +/-5.8 ml/s and 17.3 +/- 6.8 ml/s. The difference was significant (P < 0.05). The maximum urethral pressure of the combined treatment group decreased from 92.5 +/- 15.3 cm H2O to 72.5 +/- 13.4 cm H2O, while that of the control group decreased from 93.2 +/- 14.8 cm H2O to 91.7 +/- 13.6 cm H2O.

CONCLUSION

Alpha1-adrenoceptor blocker can lower the intraurethral pressure, which prevents urine from refluxing to the prostate. Alpha1-adrenoceptor blocker combined with antibiotics is effective for chronic prostatitis.

[Clinical analysis of 15 cases of Paget's disease of the scrotum]

OBJECTIVE

To study the clinicopathologic features and treatment of Paget's disease of the scrotum.

METHODS

Fifteen cases of Paget's disease of the scrotum, pathologically diagnosed and successfully treated by surgery from 1987 to 2003, were studied retrospectively.

RESULTS

Typical pathological features were observed in all the patients. Thirteen cases were followed up for 0. 5 approximately 13 years, of whom 1 case relapsed within 3 years, 2 died of metastasis after 2 years, and 3 died of cardiovascular diseases, with no recurrence in the others.

CONCLUSION

Early biopsy and extensive excision of the scrotal lesion is the first choice of treatment for Paget's disease, with good operative effect and satisfactory prognosis. A 2nd operation could be considered for patients of local relapse.

Impaired regulation of neuronal nitric oxide synthase and heart rate during exercise in mice lacking one nNOS allele

We tested the hypothesis that a single allele deletion of neuronal nitric oxide synthase (nNOS) would impair the neural control of heart rate following physical training, and that this phenotype could be restored following targeted gene transfer of nNOS. Voluntary wheel-running (+EX) in heterozygous nNOS knockout mice (nNOS(+/-), +EX; n= 52; peak performance 9.1 +/- 1.8 km day(-1)) was undertaken and compared to wild-type mice (n= 38; 9.5 +/- 0.8 km day(-1)). In anaesthetized wild-type mice, exercise increased phenylephrine-induced bradycardia by 67% (measured as heart rate change, in beats per minute, divided by the change in arterial blood pressure, in mmHg) or pulse interval response to phenylephrine by 52% (measured as interbeat interval change, in milliseconds, divided by the change in blood pressure). Heart rate changes or interbeat interval changes in response to right vagal nerve stimulation were also enhanced by exercise in wild-type atria (P < 0.05), whereas both in vivo and in vitro responses to exercise were absent in nNOS(+/-) mice. nNOS inhibition attenuated heart rate responses to vagal nerve stimulation in all atria (P < 0.05) and normalized the responses in wild-type, +EX with respect to wild-type with no exercise (-EX) atria. Atrial nNOS mRNA and protein were increased in wild-type, +EX compared to wild-type, -EX (P < 0.05), although exercise failed to have any effect in nNOS(+/-) atria. In vivo nNOS gene transfer using adenoviruses targeted to atrial ganglia enhanced choline acetyltransferase-nNOS co-localization (P < 0.05) and increased phenylephrine-induced bradycardia in vivo and heart rate responses to vagal nerve stimulation in vitro compared to gene transfer of enhanced green fluorescent protein (eGFP, P < 0.01). This difference was abolished by nNOS inhibition (P < 0.05). In conclusion, genomic regulation of NO bioavailability from nNOS in cardiac autonomic ganglia in response to training is dependent on both alleles of the gene. Although basal expression of nNOS is normal, polymorphisms of nNOS may interfere with neural regulation of heart rate following training. Targeted gene transfer of nNOS can restore this impairment.

[Diagnosis and treatment of tuberculosis in the male genital system]

OBJECTIVE

To probe into and improve the diagnosis and treatment of tuberculosis (TB) in the male genital system.

METHODS

Fifteen patients with the male genital system TB established by microbiological and pathological examinations were retrospectively reviewed.

RESULTS

The male genital system TB was diagnosed by history, physical examination, semen analysis, TB culture and biopsy. Treatment consisted of antituberculous chemotherapy for all the patients before and/or after operation, including 5 cases of epididymectomy and 6 cases of orchi-epididymectomy.

CONCLUSION

The male genital system TB tends to be atypical and semen polymerase chain reaction of TB (TB-PCR) may provide a new specific means for diagnosis in case of clinical suspicion. Surgical approaches should be cautiously adopted, especially for young patients.

Comparative antimicrobial activities of gatifloxacin, sitafloxacin and levofloxacin against Mycobacterium tuberculosis replicating within Mono Mac 6 human macrophage and A-549 type II alveolar cell lines

Mycobacterium tuberculosis (MTB) is capable of invading not only macrophages (Mphis) but also type II pneumocytes. In this study, we compared the antimicrobial activities of fluoroquinolones, including gatifloxacin, sitafloxacin and levofloxacin, against the MTB replication in the Mono Mac 6 human Mphi cell line (MM6-Mphis) and the A-549 human type II alveolar epithelial cell line (A-549 cells). When test quinolones were added at the MIC (0.125, 0.06 and 0.25 mg/l for gatifloxacin, sitafloxacin and levofloxacin, respectively) to the culture media of MTB-infected cells, these drugs exerted growth-inhibitory activity against intracellular organisms in the order of sitafloxacin > gatifloxacin > levofloxacin. On the other hand, when test quinolones were added at Cmax in the blood (1.7, 1.0 and 2.0 mg/l for gatifloxacin, sitafloxacin and levofloxacin, respectively), these drugs exhibited bactericidal activity against intracellular MTB in the order of gatifloxacin > sitafloxacin > or = levofloxacin. In addition, when test drugs were added at 1/8 C(max) to 1/2 C(max), the efficacy was in the order of sitafloxacin > gatifloxacin > levofloxacin. Thus, it appears that the MIC values of fluoroquinolones are not always predictive of their antimicrobial activity against intracellular MTB. In this context, it was also found that intracellular uptake of these quinolones by MM6-Mphis and A-549 cells was in the order of sitafloxacin > gatifloxacin > levofloxacin. This implies that the cellular permeability of these quinolones is an important factor that determines their efficacy to eliminate intracellular MTB organisms.

Molecular characterization of a distinct potyvirus from whitegrass in China

Apotyvirus isolated from perennial whitegrass ( Pennisetum centrasiaticum Tzvel.) in North China was characterized at the molecular level. The 3' terminal nucleotide (nt) sequence of 1669 nt of the viral RNA genome has been determined, which covered the coding region of the C-terminal part of the large nuclear inclusion protein (NIb, RNA polymerase), capsid protein (CP) gene and the 3' nontranslated region (NTR). The CP gene consisted of 909 nt (including the stop codon) encoding 302 amino acid residues, and the 3' NTR was 241 nt in length excluding the polyadenylated tract. Sequence comparison of the amino acids of CPs showed that this virus was most closely related to Sorghum mosaic virus and Maize dwarf mosaic virus with percent identities of 77% to 78% while that of the 3' NTRs suggested that it was most closely related to Zea mosaic virus with identity of 72%. This virus isolate was to some extent closely related to other members of the Sugarcane mosaic virus subgroup of potyviruses for the CP amino acid sequences. Phylogenetic analyses of the sequences indicated that this virus isolate represented a distinct potyvirus, and the name Pennisetum mosaic virus (PenMV) is proposed.

Efficacy of a 0.5% chlorhexidine gel on the control of gingivitis in Brazilian mentally handicapped patients

OBJECTIVE

To evaluate the effectiveness of a 0.5% chlorhexidine gel on the reduction of interdental gingival bleeding.

MATERIAL AND METHODS

Forty-three mentally handicapped subjects, living in an institution (Casas André Luiz, Brazil), were enrolled in a double-blind randomised clinical trial. The subjects were randomly divided into two groups: test (chlorhexidine gel) and control (placebo gel). The gel was applied with trays, twice a day, over a period of 8 weeks. The interdental bleeding index (IBI) was recorded before and after the period in which the gel was used.

RESULTS

Statistical analysis showed that baseline IBI scores were similar (p=0.82) for test and control groups (55.6% and 54.5%, respectively). After 8 weeks, a statistically significant (p<0.001) decrease in IBI means took place in the test group (33.2%). The control group presented a small increase (60.6%) in IBI scores. The difference between groups was significant at the end of the study (p<0.001).

CONCLUSION

The results indicated that the use of a 0.5% chlorhexidine gel was effective in reducing interdental gingival bleeding in special patients.

Neuronal nitric oxide synthase gene transfer promotes cardiac vagal gain of function

Nitric oxide (NO) generated from neuronal nitric oxide synthase (NOS-1) in intrinsic cardiac ganglia has been implicated in parasympathetic-induced bradycardia. We provide direct evidence that NOS-1 acts in a site-specific manner to promote cardiac vagal neurotransmission and bradycardia. NOS-1 gene transfer to the guinea pig right atrium increased protein expression and NOS-1 immunolocalization in cholinergic ganglia. It also increased the release of acetylcholine and enhanced the heart rate (HR) response to vagal nerve stimulation (VNS) in vitro and in vivo. NOS inhibition normalized the HR response to VNS in the NOS-1-treated group compared with the control groups (enhanced green fluorescent protein and sham) in vitro. In contrast, an acetylcholine analogue reduced HR to the same extent in all groups before and during NOS inhibition. These results demonstrate that NOS-1-derived NO acts presynaptically to facilitate vagally induced bradycardia and that upregulation of NOS-1 via gene transfer may provide a novel method for increasing cardiac vagal function.

Effect of Cervitec on mutans streptococci in plaque and on caries formation on occlusal fissures of erupting permanent molars

The aim of this study was to evaluate the effect of Cervitec on the abundance of mutans streptococci (MS) in occlusal dental plaque and on 2-year caries increment of partly erupting first permanent molars. Sixteen healthy schoolchildren aged 6-8 years, with at least 2 sound contralateral partly erupted permanent molars, received diet counselling and daily parental supervised toothbrushing with a fluoride dentifrice. Stimulated saliva samples were collected at baseline and after 1 year to evaluate MS levels. In a split-mouth design, Cervitec varnish was applied to one of the teeth at baseline and after 3 and 6 months, while the other tooth in the same jaw was a control. At the 9-month follow-up the teeth were in occlusal contact. At this time, varnish was not applied. At 3 and 6 months after the first application of varnish a significant suppression of MS was observed in plaque. Caries investigations, performed at baseline and every 3 months during the 2 years after the start of the study, showed that all the teeth treated with the varnish were free of caries after 2 years, whereas 8/16 control teeth developed incipient caries. In conclusion, our results suggest that treatment with Cervitec reduces MS in plaque on erupting permanent molars and can lead to a significant decrease in caries incidence.

Role of the disulfide cleavage induced molten globule state of type a botulinum neurotoxin in its endopeptidase activity

Botulinum neurotoxins are produced by anaerobic Clostridium botulinum in an inactive form. The endopeptidase activity of type A botulinum neurotoxin (BoNT/A) is triggered by reduction of its disulfide bond between its heavy chain and light chain. By using circular dichroism spectroscopy, we show that, upon reduction of BoNT/A and under physiological temperature (37 degrees C), the BoNT/A loses most of its native tertiary structure, while retaining most of its secondary structure. This type of structure is characterized as a molten globule type conformation, which was further confirmed for BoNT/A by the characteristic binding of 1-anilinonaphthalene-8-sulfonic acid. Under nonreducing conditions where the interchain disulfide bond is intact, the enzymatically inactive BoNT/A did not show a molten globule type of structure. A temperature profile of the structure and enzyme activity of BoNT/A revealed that, under reducing conditions, there was a strong correlation in the existence of the molten globule structure and optimum endopeptidase activity at about 37 degrees C.

[Effect of hypertonic saline solution on the viscoelasticities of erythrocyte membrane in rats subjected to hemorrhagic shock]

We have studied the effect of hypertonic saline solution on the viscoelasticities of erythrocyte membrane in hemorrhage-shocked rats using micropippette aspiration technique. Wistar rats were randomly divided into three groups of 0.9% NaCl(NS), 7.5% NaCl (HS) and 5% NaCl-3.5% NaAc (HSA), respectively. The animals were bled to reach a mean arterial pressure of 5.3 kPa in 10 minutes and maintained in shock for 90 minutes. 4 ml/kg NS, HS and HSA was given intravenously and respectively in 5 minutes following hemorrhagic shock. The blood was collected to determine the viscoelasticities of erythrocyte membrane at baseline, shock and after treatment. The results showed that the elastic moduli and viscous coefficients of erythrocyte membrane were increased obviously following hemorrhagic shock. HS raised elastic moduli and reduced viscous coefficients significantly compared with NS after treatment. The elastic moduli and viscous coefficients of erythrocyte membrane were decreased remarkably in HSA group than in NS and HS group. These data suggested that HSA could improve the viscoelasticities of erythrocyte membrane significantly in rats subjected to hemorrhagic shock.