Timing jitter in soliton transmission with sliding filters

We show that the coupling between amplitude and frequency f luctuations that is due to filter sliding significantly enhances timing jitter in soliton transmission controlled by in-line filters. This is the likely reason for the extra timing jitter observed in a recent soliton transmission experiment using sliding filters.

Evaluation of inhA gene and catalase-peroxidase gene among isoniazid-sensitive and resistant Mycobacterium tuberculosis isolates

The katG gene and the inhA gene of 30 INH-resistant (INH-R) and 28 INH-sensitive (INH-S) isolates of M. tuberculosis from Haiti and Maryland were analysed by PCR to establish the presence and frequency of two postulated mechanisms of INH-resistance, total katG gene deletion and inhA Ser94 to Ala94 amino acid substitution. Only two of 30 INH-R isolates (3%) appear to have total katG gene deletions. All 28 INH-S isolates (100%) produced a PCR product at both the 5' and the 3' ends of the katG gene. Gene deletion of katG is a rare mechanism of INH resistance. Allele specific oligonucleotide hybridisation analysis of the inhA PCR products from the same 58 isolates revealed no mutation at amino acid 94 or directly surrounding it. Other inhA gene mutations may be responsible for INH resistance in M. tuberculosis. Diagnostic strategies using katG gene deletion or inhA Ser94 mutations would fail to detect almost all INH-R isolates.

Self-induced modulational-instability laser

We analyze the transition from passive mode locking into the novel modulational-instability regime of erbiumdoped fiber lasers. By including in the cavity an anisotropic loss, we observed, depending on the polarization setting, the generation of either single pulses as short as 435 fs or a continuous-wave train of 3.5-ps-long solitons at a repetition rate of 76 GHz. Even with no anisotropic losses in the cavity, soliton trains at a repetition rate of as high as 130 GHz were still observed. We believe that this is the first observation of a self-induced modulational-instability laser.

[Leukocytic procoagulant activity and chemotherapeutic drugs: the comparative effects of cisplatin and carboplatin on lympho-/monocytic procoagulant activity in vitro]

It is well known that a number of chemotherapeutic agents are able to induce procoagulating activity not only in neoplastic cells but also in normal, monocyte/macrophage cells, and some of them, including cisplatin, even increase procoagulating activity of the factor already expressed, providing a further example of the possible co-participation of chemotherapy in the onset of thrombotic complications in cancer patients. Carboplatin is an analogue of cisplatin but differs strikingly in terms of its collateral effects, in particular being less oto- and nephrotoxic. To the authors' knowledge there are no data regarding the possible effect of carboplatin on lympho/monocyte procoagulating activity. This study shows that not only platin but also carboplatin is able to increment the levels of lympho/monocyte procoagulating activity in vitro, with a dose-dependent effect, and to synergize with bacterial endotoxin in increasing this leukocyte activity, although the synergic effect is significantly greater in the case of carboplatin. The importance of these findings at a practical and clinical and clinical level still remains to be defined, in particular in the light of the different pharmacokinetic behaviour of these two chemotherapeutic agents and in the context of those neoplastic diseases for which cisplatin and carboplatin treatment is most frequently used.

[Leukocyte procoagulant activity and chemotherapeutic agents: comparison between the effects of adriamycin and epiadriamycin on the procoagulant lympho/monocytic activity in vitro]

It is well known that a number of antineoplastic agents are able to induce procoagulant cellular activity and tissue factor not only in neoplastic cells but also in normal, monocyte/macrophage cells, and some of them, including adriamycin, even increase procoagulating activity of the factor already expressed, providing a further example of the possible co-participation of chemotherapy in the onset of thrombotic complication in cancer patient. Epirubicin is an analogue of adriamycin but differs strikingly in terms of its collateral effect, in particular being less cardiotoxic. To the authors' knowledge there are no data regarding the possible effect of epirubicin on lympho/monocyte procoagulant activity. This study shows that not only adriamycin but also epirubicin is able to increment the level of lympho/monocyte procoagulant activity "in vitro", with a dose-dependent effect, and to synergize with bacterial endotoxin in increasing this leukocyte activity, although the effect is significantly greater in the case of adriamycin. The importance of these findings at practical and clinical level remains to be defined, in particular in the length of the different pharmacokinetic behavior of these two chemotherapeutic agents and in the context of those neoplastic diseases for which adriamycin and Epirubicin treatment is most frequently used.

Captopril treatment of chronic heart failure in the very old

BACKGROUND

The safety and efficacy of angiotensin-converting enzyme inhibitors for very old patients with chronic heart failure have been less well documented than for younger patients.

METHODS

A prospective, randomized double-blind, placebo-controlled study of captopril, 25 mg twice daily, was designed. Fifty patients (mean age 84.2 +/- 5.2) participated. The degree of chronic heart failure (according to the Boston Study Group rating), the distance walked in 6 minutes, and the occurrence of uncontrolled heart failure and adverse reactions were used as main outcome measures.

RESULTS

Significantly more patients receiving placebo developed uncontrolled heart failure than patients receiving captopril (p = .022). In an intention to treat analysis, the first and last evaluations of the degree of chronic heart failure were compared. A significantly different evolution was observed between the two treatment groups (p < .001), with a significant improvement only in the captopril-treated patients (p < .001). The distance walked in 6 minutes improved significantly only in the captopril group (p = .004). The only adverse reaction was rash in two patients receiving captopril.

CONCLUSIONS

The study gives further evidence that angiotensin-converting enzyme inhibitor treatment for very old patients with chronic heart failure is useful.

Adiabatic femtosecond soliton active nonlinear directional coupler

The optimal all-optical switching, amplification, and temporal compression of femtosecond solitons by means of a nonlinear erbium-doped twin-core fiber may be achieved by suitably tapering the linear coupling strength. We analytically show that, irrespective of the soliton self-frequency shift, tapering may in principle reduce the switching power threshold to arbitrarily low values. A substantial reduction is also demonstrated in a practical case in which the full complex susceptibility of the erbium doping and the Raman response function are considered.

[Cystic parotid lesions in HIV infection]

The appearance of parotid lesions of cystic aspect with a HIV's infections has been described in the past by foreign Authors above all coming from USA and from Africa. Similar cases has been recorded in France but only among children. The Authors report a casuistry constituted by five male sex's and white race's subjects, everyone HIV positive, suffering from mono or bilateral benign lymphoepithelial cysts. Every patient under examination presented a positive history because of the use of intravenous drug. Four of the five subjects underwent a surgical treatment of parotidectomy. Echotomography, CT and RM scanning seem to be the more sensitive diagnostic techniques. The peculiar histopathologic aspects allow us to differentiate these lesions both from the classical benign lymphoepithelial cysts and from the Warthin's tumor. The increase of the signalling of these cases seems to be connected with the progressive diffusion of the infection and with major survival of the patients thanks to chemotherapy. The majority of the Authors is agreed to recommend the surgical treatment for the possible malignant degeneration of this kind of forms. A careful clinical and diagnostic analysis of every patient with parotid swelling, above all if at risk for HIV's infection, is strictly necessary.

Role of pump-induced dispersion on femtosecond soliton amplification in erbium-doped fibers

The limitation to the amplification of femtosecond pulses by erbium-doped fibers owing to the soliton self-frequency shift may be overcome by using a dispersion-shifted fiber. We show that this result holds irrespective of the relatively large residual frequency-dependent chromatic dispersion that is associated with the pumping of the doping ions. Nevertheless, resonant dispersion may lead to temporal broadening and distortion of the amplified pulse.

Epstein-Barr virus-related persistent erythema multiforme in chronic fatigue syndrome

BACKGROUND

Erythema multiforme (EM) has been rarely reported in Epstein-Barr virus (EBV)-associated diseases; this includes patients with chronic fatigue syndrome who have chronic or recurrent and disabling illness and an abnormal antibody reactivity to EBV. We describe a patient fulfilling the chronic fatigue syndrome diagnostic criteria who had developed an unusually persistent EM resistant to corticosteroids therapy. The EBV DNA was studied in skin EM lesions, throat washings, peripheral mononuclear cells, and plasma. The EBV antigens were studied in skin EM lesions and in mononuclear cells. The patient was followed up to 2 years.

OBSERVATIONS

The patient had abnormal titers of antibodies against various EBV antigens and by immunofluorescence she disclosed the EBV nuclear antigen and the viral capsid antigen in the blood vessels of the affected skin. The dot blot hybridization assay detected viral DNA in throat washings and mononuclear cells, but not in plasma. The presence of the viral genomic content in lesional skin is suggested by the autoradiographic signal and by the difference from appropriate control specimens. Skin lesions and constitutional symptoms cleared after acyclovir sodium therapy and recurred after discontinuation of this therapy.

CONCLUSIONS

This is the first EM case in which evidence of the EBV causal role has been provided. The association with chronic fatigue syndrome suggests the EBV role in selected cases of this syndrome.

Blood-brain-barrier in a geriatric population: barrier function in degenerative and vascular dementias

Albumin and IgG were determined in serum and cerebrospinal fluid (CSF) of patients with early-onset Alzheimer's disease (AD, n. 13), senile dementia of Alzheimer type (SDAT, n. 33), vascular dementia divided into multi-infarct (MID, n. 9) and probable vascular (PVD, n. 11) dementia. Albumin and IgG ratio and IgG index were calculated. CSF albumin and albumin ratio were significantly higher in MID patients indicating an increased BBB permeability. IgG ratio and IgG index did not show any significant difference among groups. These results do not provide evidence for BBB damage in AD/SDAT, while in MID the increase of CSF albumin and albumin ratio is suggestive of BBB dysfunction.

Ultrashort soliton switching based on coherent energy hiding

Coherent coupling between light and atoms may be exploited for conceiving a novel class of all-optical signalprocessing devices without a direct counterpart in the continuous-wave regime. We show that the self-switching of ultrashort soliton pulses on resonance with a transition of doping centers in a slab waveguide directional coupler is based on nonlinear group-velocity (instead of the usual phase-velocity) changes.

[Mean high-amplification electrocardiogram during a submaximal exercise test following acute myocardial infarction]

The mean high-amplification ECG (MECG) used to detect delayed potentials (DPs) has so far been used only at rest and after exertion. In this article, the results are reported of recording the MECG at rest and during exercise (ER) obtained in 19 patients, the ER having been carried out at the subacute stage of myocardial infarction. Despite a significant increase in the background noise during exercise from 0.9 microV to 2.2 microV, it was possible to analyse the MECG recorded during exercise to detect DPs in all cases. In this small group of patients, no significant changes occurred with regard to the appearance or delayed potentials during exercise, although there was a reduction in the duration of HFQRS and an increase in the amplitude of RMS40 during exercise which was, however, much less marked in patients presenting DP.

Third-order nonlinearity enhancement in an artificial Kerr medium through bulk intrinsic birefringence

Laser-induced circular birefringence measurements have been performed on a liquid suspension of polymer microellipsoids in order to study its optical nonlinearity as a function of the host liquid's refractive index n(h). The results show that the large values obtained for the chi1221((3)) term (1.6 x 10(-8) esu for n(h) = 1.330) can be explained with an intrinsic birefringence of the microellipsoids relative to their geometrical axes. The obtained values for the refractive indices are n || = 1.391 and n perpendicular = 1.368.