Catecholamines promote the expression of virulence and oxidative stress genes in Porphyromonas gingivalis.

BACKGROUND AND OBJECTIVE: Stress has been identified as an important risk factor in the development of many infectious diseases, including periodontitis. Porphyromonas gingivalis, a gram-negative oral anaerobic bacterium, is considered an important pathogen in chronic periodontitis. Microorganisms, including P. gingivalis, that participate in infectious diseases have been shown to respond to catecholamines released during stress processes by modifying their growth and virulence. Therefore, the purpose of this study was to evaluate the effects of adrenaline and noradrenaline on the growth, antimicrobial susceptibility and gene expression in P. gingivalis. MATERIAL AND METHODS: P. gingivalis was incubated in the presence of adrenaline and noradrenaline (100 µm) for different time-periods in rich (Tryptic soy broth supplemented with 0.2% yeast extract, 5 µg/mL of hemin and 1 µg/mL of menadione) and poor (serum-SAPI minimal medium and serum-SAPI minimal medium supplemented with 5 µg/mL of hemin and 1 µg/mL of menadione) media, and growth was evaluated based on absorbance at 660 nm. Bacterial susceptibility to metronidazole was examined after exposure to adrenaline and noradrenaline. The expression of genes involved in iron acquisition, stress oxidative protection and virulence were also evaluated using RT-quantitative PCR. RESULTS: Catecholamines did not interfere with the growth of P. gingivalis, regardless of nutritional or hemin conditions. In addition, bacterial susceptibility to metronidazole was not modified by exposure to adrenaline or noradrenaline. However, the expression of genes related to iron acquisition (hmuR), oxidative stress (tpx, oxyR, dps, sodB and aphC) and pathogenesis (hem, hagA and ragA) were stimulated upon exposure to adrenaline and/or noradrenaline. CONCLUSION: Adrenaline and noradrenaline can induce changes in gene expression related to oxidative stress and virulence factors in P. gingivalis. The present study is, in part, a step toward understanding the stress-pathogen interactions that may occur in periodontal disease.

Production and perception of final consonant voicing in speech produced by inexperienced signers during simultaneous communication.

Simultaneous communications combines both spoken and manual modes to produce each word of an utterance. This study investigated the potential influence of alterations in the temporal structure of speech produced by inexperienced signers during simultaneous communication on the perception of final consonant voicing. Inexperienced signers recorded words that differed only in the voicing characteristic of the final consonant under two conditions: (1) speech alone and (2) simultaneous communication. The words were subsequently digitally edited to remove the final consonant and played to 20 listeners who, in a forced-choice paradigm, circled the word they thought they heard. Results indicated that accurate perception of final consonant voicing was not impaired by changes in the temporal structure of speech that accompanied the inexperienced signers' simultaneous communication.

[Hypotension during acute myocardial infarct. Different pattern of parameters of renal function in relation to the localization of necrosis]. / Ipotensione durante IMA. Diverso contegno di alcuni parametri di funzione renale in rapporto alla sede di necrosi.

BACKGROUND: The influence on renal function caused by acute myocardial infarction complicated by hypotension has been studied. Particularly, a possible difference in renal functional pattern related to different localization and/or extension of necrotic myocardial area was investigated. METHODS: The study has been performed in 12 cases of acute myocardial infarction, involving anteroseptal (7) or inferodorsal (5) myocardial wall. The score of parietal asynergy resulted 13.28 in anterior vs 7.6 in inferior localization (p < 0.001). RESULTS: The decrease in systolic pressure, conversely, resulted not significantly different in the two groups. The renal function was assessed by measuring the urinary output (V) and creatinine clearance (CrCl). During the first 24 hours, both parameters resulted more preserved in inferior than in anterior AMI (V-552 vs 214 ml; p < 0.005; CrCl 70.6 vs 33.42; p < 0.001). Thus 1) the pressure decrease resulted unrelated to the size of asynergy and 2) the markers of renal function, although the decrease in brachial pressure has been identical in the two groups, have been shown to decrease more profoundly in the anterior infarction. DISCUSSION AND CONCLUSIONS: This may depends upon the reflex interruption of efferent nervous sympathetic drive toward the renal arteriolar bed, occurring in inferior infarction, despite of the systemic hypotension, and able to exercising a beneficial influence on the glomerular filtration rate (GFR). This reflex modulation has been demonstrated as effective in the inferior, but not in the anterior localization of infarction, this different haemodynamic pattern being able to explain the more pronounced decrease in GFR and diuresis in anterior than inferior AMI, as observed in our study.

[Abnormal vasomotor response of the forearm due to propranolol-induced loss of cardiopulmonary baroreflex sensitivity: experience with seven cases of recent myocardial infarct]. / Abnorme risposta vasomotoria dell'avambraccio da perdita della sensibilità baroriflessa cardiopolmonare correlata a trattamento con propranololo: esperienza su sette casi di infarto miocardico recente.

In 7 patients suffering from acute myocardial infarction (AMI) occurring in the previous 30 days, we investigated forearm vascular reactivity to lower body negative pressure (LBNP), by the strain gauge plethysmography with simultaneous administration of negative pressure around the lower limbs. This manoeuvre has then been repeated after 10 days of oral beta-blocker therapy (propanolol 160 mg/die). A significant flow reduction derived from LBNP associated to plethysmography with respect to plethysmography alone, but this significant difference was suppressed by propranolol treatment, that prevented the reflex decrease in forearm blood flow, (forearm blood flow from 5.97 to 3.85 ml/min/100 ml in wash-out vs 5.64 to 5.75 ml/min/100 ml during propranolol treatment). We hypothesize that this phenomenon is due to the desensitizing effect of propranolol on cardiopulmonary mechanoreceptors (CPB), with the consequent loss or reduction of their functional inhibition for the efferent sympathetic outflow towards resistance vessels in skeletal muscle. Therefore, LBNP does not elicit forearm reflex sympathetic vasoconstriction, because pressure unloading of CPB areas is no longer able to modify sympathetic discharge, since the influence on it of baroreceptor activity has already been weakened by prolonged beta-blockade. Thus, the LBNP low levels, by ruling out and/or by removing the CPB activity are theorically able to elicit sympathetic "disinhibition", and to exercise, consequently, a reflex, vasoconstrictor influence upon the forearm vascular bed, whereas the same reflex behaviour by forearm resistance vessels does not appear feasible if the CPB activity has been preventively minimized by prolonged, chronic beta-blockade.

Correction of crossover second toe deformity.

Crossover second toe deformity is a common, but quite difficult, condition to treat. Its causes are multifactoral but resultant clinical findings are fairly constant. An aggressive surgical approach is mandatory to produce permanent correction. This involves a combination of soft-tissue and appropriate osseous reconstruction.

A surgical alternative in the management of chronic neurotrophic ulcerations of the foot.

Chronic neurotrophic ulcerations involving weightbearing portions of the foot present a unique management challenge. Under the appropriate clinical setting, muscle transposition can be a rewarding operation in managing these otherwise unresponsive pedal ulcerations. Presented herein is a case demonstrating the successful resolution of a recalcitrant ulceration. The authors recommend this approach, not as a replacement, but merely as an alternative to more traditional techniques.

Muscle transposition in the management of chronic osteomyelitis and ulceration of the heel.

Transposition of intrinsic muscles of the foot may be beneficial for coverage of local full-thickness defects. A case representing this situation is presented. The authors report successful resolution of the procedure 28 months postoperatively.

Crush and avulsion injuries of the foot: their evaluation and management.

It is difficult to assess the damage resulting from crush or avulsion injuries so they may be treated adequately. The authors present a systematic approach to evaluating tissue involved in foot trauma. They also discuss antibiotic and tetanus prophylaxis and a technique of bacterial quantification that is helpful in determining the advisability of primary or delayed wound closure.