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Biomedical subjects

F Lombardi

Publications and source records attributed to F Lombardi.

At least 19 recordsLinked to original sources
PubMed1995

Adenosine activates cardiac sympathetic afferent fibers and potentiates the excitation induced by coronary occlusion.

Adenosine is a possible mediator of cardiac pain during myocardial ischemia; however, little is known about the influence of adenosine on cardiac sympathetic afferent activity and thereby on its algogenic mechanism. In 20 anaesthetized, decerebrated, curarized and artificially ventilated cats, we studied the impulse activity of 20 single afferent sympathetic fibers with a left ventricular receptive field in relation to epicardial applications of adenosine, coronary artery occlusions and arterial pressure rises. All fibers increased their impulse activity (from 1.2 +/- 0.2 to 2.6 +/- 0.5 imp/s; P < 0.001) during slight (20 +/- 8%) rises in aortic pressure, thus exhibiting low-threshold receptor characteristics. In 10 cats, epicardial applications of three different doses of adenosine (0.1, 1 and 10 mg/ml) caused a brief increase in neural activity with dose-related responses. This response was abolished by aminophylline, a P1 purinergic inhibitor. In the other group of 10 cats, four subsequent 30-s occlusions of the coronary arterial vessel supplying the receptive fields of the fibers were performed, in control conditions and 30 s, 3 and 7 min, respectively, after the end of excitation induced by adenosine (1 mg/ml) application. During the control coronary occlusion the impulse activity increased from 1.1 +/- 0.1 to 5.5 +/- 0.7 imp/s (P < 0.0001). A similar activation was present during the second occlusion initiated 30 s after the end of adenosine-induced activation. In contrast, a significant potentiation of the response was observed (8.8 +/- 1.2 vs. 5.3 +/- 0.9 imp/s; P < 0.001) during the occlusion initiated 3 min after the end of excitation by adenosine. This effect was no longer present during the last occlusion performed after 7 min. When the protocol was repeated substituting adenosine with saline (n = 5) or after i.v. administration of aminophylline (n = 5), no potentiation was observed, even though the excitatory response to coronary occlusion was preserved. These data show that adenosine can activate cardiac sympathetic afferent fibers in a dose-related manner, and potentiate their responses to coronary occlusion, while leaving unaffected the responsiveness to a hemodynamic stimulus. The excitatory effects are likely to involve the P1 purinergic receptors. The potentiation phenomenon might play a role in the genesis of an algogenic code.

Adenosine↗
PubMed1995

Determination of the polar drug dimiracetam in human plasma and serum by column-switching high-performance liquid chromatography.

A sensitive and fully automated column-switching HPLC method was developed for the determination of a novel cognition enhancer, dimiracetam, in human plasma and serum. A sample of plasma was ultrafiltered and then directly injected onto a first mu Bondapak C18 column. The sample was eluted with water. The portion of the eluate (heart-cut) from this column containing the drug was selected and loaded on a second mu Bondapak C18 column and eluted with water. During the elution of the second column, the first column was automatically rinsed with water-acetonitrile (50:50, v/v) and then equilibrated for a new injection. The total analysis time for each sample was 35 min. This corresponded to a 30% decrease in analysis time compared with the time that would have been needed with a simple run with two mu Bondapak C18 columns assembled in series. Ultraviolet detection at 200 nm was used to monitor the eluate. The method was fully validated over the quantitation range 27 ng/ml-15 micrograms/ml. The applicability of the method was demonstrated by analysis of serum samples from a study performed in human healthy volunteers.

Chromatography, High Pressure Liquid↗
PubMed1995

Pure Autonomic Failure: complex abnormalities in the neural mechanisms regulating the cardiovascular system.

The aim of this study was to evaluate the sympatho-vagal interaction modulating cardiovascular function and the possible impairment of baroreceptor sensitivity in patients affected by Pure Autonomic Failure (PAF). We studied 4 patients affected by PAF and 7 controls at rest and during different levels (45 degrees, 60 degrees, 90 degrees) of head-up tilt. On a different day all subjects underwent i.v. administration of phenylephrine at dosages adequate to enhance systolic blood pressure by about 20 mmHg both at rest and during 45 degrees head-up tilt. Finally, 1.5 mg atropine was infused intravenously only in the patients. Spectral analysis of RR interval and systolic arterial pressure (SAP) variabilities provided markers of sympathetic (low-frequency oscillations, about 0.1 Hz, LFRR) and vagal (high-frequency oscillations, about 0.25 Hz, HFRR) modulations of heart period and of sympathetic vasomotor activity (low-frequency oscillations of SAP variability, LFSAP). Baroreceptor mechanisms were quantified by means of the index alpha (calculated from the square root of the ratio between the powers of HF components of RR interval and SAP variabilities) and of the phenylephrine RR-SAP slope. Patients affected by PAF were characterized by a drastic decrease in total power of RR variability and by the absence of LFRR and LFSAP components. Moreover, HFRR, although largely predominant in its relative value, was also markedly reduced in its absolute value. Finally, the baroreceptive mechanisms appeared to be heavily impaired. In conclusion, PAF patients seem to be characterized by a complex alteration of neural mechanisms, which in addition to the signs of a sympathetic denervation include an impairment, at least functional, of the vagal modulation of heart rate.

Atropine↗
PubMed1994

Effects of beta blockers (atenolol or metoprolol) on heart rate variability after acute myocardial infarction.

This study analyzed, with spectral techniques, the effects of atenolol or metoprolol on RR interval variability in 20 patients 4 weeks after the first uncomplicated myocardial infarction. Beta blocker-induced bradycardia was associated with a significant increase in the average 24-hour values of RR variance (from 13,886 +/- 1,479 to 16,728 +/- 1,891 ms2) and of the normalized power of the high-frequency component (from 22 +/- 1 to 28 +/- 2 normalized units), whereas the low-frequency component was greatly reduced (from 60 +/- 3 to 50 +/- 3 normalized units). When considering day and nighttime separately, the effects of both drugs were more pronounced in the daytime. In addition, a marked attenuation was observed in the circadian variation of the low-frequency component after beta blockade. As a result, the early morning increase of the spectral index of sympathetic modulation was no longer detectable. These results indicate that beta-blocker administration has important effects on RR interval variability and on its spectral components. The observed reduction in signs of sympathetic activation and the increase in vagal tone after beta blockade help to explain the beneficial effects of these drugs after myocardial infarction. However, the potential clinical relevance of the increase in RR variance remains to be established.

Atenolol↗
PubMed1994

Long-term outcome of patients with monostotic Ewing's sarcoma treated with combined modality.

One hundred and twenty-one consecutive patients with monostotic Ewing's sarcoma (ES) were treated according to three consecutive combined modality programs from 1974 to 1986. Their 3-year progression free survival (PFS) rate from diagnosis of 59% was identical to the event free survival (EFS) rate, since all the 50 events occurring within 3 years from diagnosis were tumor recurrences. Primary tumor was treated with radiotherapy in 75 cases, surgical resection plus radiotherapy in 38, and radical surgery in 8. Chemotherapy was given to all patients and each program included adriamycin, vincristine, and cyclophosphamide +/- dactinomycin. Median follow-up was 12 years, ranging from 6 to 19 years. The PFS rate decreased to 49% at 6 years and plateaued at 46% after the 7th year from diagnosis, even though some relapses were observed as late as 14 years from diagnosis. Second malignancies developed in 7 patients free from progressive ES and were represented by osteogenic sarcoma in previously irradiated bone in 4 cases and by breast carcinoma in 3. No other event but tumor relapse or second malignancy occurred in this series. EFS rate was 47% at 6 years and 39% at 12 years, further decreasing in the following years because of a number of late events. A continuous PFS longer than 7 years may be consistent with cure in the majority of patients with monostotic ES. However, these patients should be followed indefinitely because of risk of second malignancies.

Adolescent↗
PubMed1994

Total rectal resection and colo-anal anastomosis with colonic reservoir for low rectal cancer.

From March 1990 to December 1992, 47 patients with primary or recurrent low rectal cancer underwent total rectal resection and a coloendoanal anastomosis. Rectal resection was extended downward to the ano-rectal junction. The restorative technique included a colo-endoanal anastomosis between the dentate line and a J-shaped colic reservoir. All lesions were located within 7 cm of the anal verge (within 6 cm in 33 primary cases). Macroscopic and histological radicality was documented in all cases. Pelvic recurrence occurred in six patients and was para-anastomotic in one case. Post-operative morbidity was low. Perfect continence was documented in 36 patients and 72 of the cases had one or two bowel movements a day. All but four patients are alive at a follow-up ranging from 6 to 40 months (median 20 months). This approach is a safe option to conventional total rectal excision with permanent colostomy for lower third rectal carcinoma.

Adenocarcinoma↗
PubMed1994

Model for the assessment of heart period and arterial pressure variability interactions and of respiration influences.

A model which assesses the closed-loop interaction between heart period (HP) and arterial pressure (AP) variabilities and the influence of respiration on both is applied to evaluate the sources of low frequency (LF approximately 0.1 Hz) and high frequency (HF, respiratory rate approximately 0.25 Hz) in conscious dogs (n = 18) and humans (n = 5). A resonance of AP closed-loop regulation is found to amplify LF oscillations. In dogs, the resonance gain increases slightly during baroreceptor unloading (mild hypotension obtained with nitroglycerine (NTG) i.v. infusion, n = 8) and coronary artery occlusion ((CAO), n = 6), and it is abolished by ganglionic transmission blockade ((ARF), Arfonad i.v. infusion, n = 3). In humans, this gain is considerably increased by passive tilt. Different, possibly central, sources of LF oscillations are also evaluated, finding a strong rhythmic modulation of HP during CAO. At HF, a direct respiratory arrhythmia is dominant in dogs at control, while it is considerably reduced during CAO. On the contrary, in humans, a strong influence of respiration on AP is shown which induces a reflex respiratory arrhythmia. An index of the gain of baroreceptive response, alpha cl, was decreased by NTG and CAO, and virtually abolished by chronic arterial baroreceptive denervation (TABD, n = 4) and ARF.

Animals↗
PubMed1994

Durability of hematopoiesis following autografting with peripheral blood hematopoietic progenitors.

BACKGROUND: It is still not known whether hematopoiesis reconstituted by autografting with the peripheral blood hematopoietic progenitors (CPCs) after myeloablative high dose radiotherapy and/or chemotherapy is durable and capable of coping with the increased demand imposed by boost radiotherapy, surgery, or infection. PATIENTS AND METHODS: The durability of hematopoiesis was evaluated in 34 consecutive cancer patients treated with myeloablative total body irradiation (n = 17, median follow-up 3 years, range 3-49 months) and/or alkylating-agent chemotherapy (n = 17, median follow-up 8 months, range 6-41 months) and autografted with CPCs because bone marrow autografting was contraindicated. CPCs (> or = 8 x 10(6) CD34 + cells/kg) had been collected during mobilization into the circulation in response to previous anticancer therapy and hematopoietic growth factor(s). RESULTS: Following brief temporary pancytopenia, all patients achieved normal and durable hematopoiesis. The newly reconstituted hematopoietic system was capable of reacting favorably to stressful and debilitating events such as surgery, radiotherapy, or varicella-zoster infection. No secondary irreversible failure of blood cell production occurred. CONCLUSIONS: The documentation of the durability of normal hematopoiesis following myeloablative cancer therapy and autografting with mobilized CPCs implies that the latter procedure, rather than being solely an alternative to bone marrow autografting, represents an advantageous tool of choice permitting substantial amelioration of the therapeutic index of high-dose cancer therapy.

Adult↗
PubMed1994

Power spectrum analysis of heart rate variability to assess the changes in sympathovagal balance during graded orthostatic tilt.

BACKGROUND: The powers of the low-frequency (LF) and high-frequency (HF) oscillations characterizing heart rate variability (HRV) appear to reflect, in their reciprocal relationship, changes in the state of the sympathovagal balance occurring during numerous physiological and pathophysiological conditions. However, no adequate information is available on the quantitative resolution of this methodology. METHODS AND RESULTS: We studied 22 healthy volunteers (median age, 46.5 years) who were subjected after a rest period to a series of passive head-up tilt steps randomly chosen from the following angles: 15 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees. From the continuous ECG, after appropriate analog-to-digital conversion, a personal computer was used to compute, with an autoregressive methodology, time and frequency domain indexes of RR interval variability. Spectral and cross-spectral analysis with the simultaneously recorded respiratory signal excluded its contribution to LF. Age was significantly correlated to variance and to the absolute values in milliseconds squared of very-low-frequency (VLF), LF, and HF components. The tilt angle was correlated to both LF and HF (expressed in normalized units [nu]) and to the LF-to-HF ratio (r = .78, -.72, and .68; respectively). Lower levels of correlation were found with HF (in ms2) and RR interval. No correlation was present between tilt angle and variance, VLF, or LF (in ms2). Individual analysis confirmed that the use of nu provided the greatest consistency of results. CONCLUSIONS: Spectral analysis of HRV, using nu or LF-to-HF ratio, appears to be capable of providing a noninvasive quantitative evaluation of graded changes in the state of the sympathovagal balance.

Adult↗
PubMed1994

A cooperative study on ProMACE-CytaBOM in aggressive non-Hodgkin's lymphomas.

Chemotherapy using cyclophosphamide, doxorubicin, etoposide, cytarabine, bleomycin, vincristine, methotrexate with leucovorin, and prednisone (ProMACE-CytaBOM) for patients with intermediate or high grade non-Hodgkin lymphomas (G, H and K according to the Working Formulation), was tested by the Gruppo Cooperativo Lombardo to confirm the activity of the regimen and to test the feasibility and safety of administering third-generation drug regimen in a cooperative group setting. Among 64 previously untreated patients, aged between 20 and 71 years, 7 had stage IB-IIB, 12 had stage IIIA-B, 45 (67%) had stage IVA-B. There were 44 complete remissions (CRs) (69%) and 14 partial remissions (22%); the difference between patients in stage I-II-III (84% complete remissions) and those in stage IV (62% complete remissions) was statistically significant. The median length of follow up was 20 months (range 1-60 months), with 56% of patients alive at 60 months and 53% of CRs patients free of disease at 60 months. Patients in stage I-II-III have the best survival and disease free survival compared to stage IV, 87% versus 42% and 72% versus 32% respectively (both with high statistical significance). Grade 3-4 (WHO) haematological toxicity was observed in 39% of patients, with 3 septic deaths. Two more patients died with chemotherapy related toxicity (1 stroke and 1 acute renal insufficiency). Administration of ProMACE-CytaBOM is a feasible and safe regimen although it presents moderate toxicity. ProMACE-CytaBOM may represent improved treatment for aggressive lymphomas, in terms of duration of response and survival, but a longer follow up is needed.

Adolescent↗
PubMed1994

[Methods for assessing the autonomic nervous system in man].

Assessment of baroreflex sensitivity and spectral analysis of heart rate variability are two methods capable of providing relevant information on neural mechanisms controlling heart period and on their alterations during several pathophysiological conditions such as coronary artery disease and cardiac insufficiency. These techniques provide complementary information: the former is based on a stimulus-response model which has in the activation of vagal fibers directed to the heart its main efferent component; the latter, by quantifying the spontaneous harmonic oscillations of heart period, furnishes indices of sympathetic and vagal modulation of sinus node.

Autonomic Nervous System↗
PubMed1993

High-dose sequential chemo-radiotherapy with peripheral blood progenitor cell support for relapsed or refractory Hodgkin's disease--a 6-year update.

BACKGROUND: Very few studies using high-dose therapy and autologous bone marrow transplantation have a long (i.e., > 3 years) follow-up. We report here the 6-year update of a study employing high-dose sequential chemo-radiotherapy in 25 patients with poor-risk Hodgkin's disease. PATIENTS AND METHODS: All patients were either refractory (7 patients) or partial responders (9 patients) or early relapses (9 patients) following induction chemotherapy consisting of MOPP/ABVD in 20 patients and MOPP/ABVD followed by salvage CEP for the remaining 5 patients. The high-dose chemo-radiotherapy regimen employed consisted in the rapid sequential administration of high-doses of cyclophosphamide, methotrexate, etoposide and total body irradiation plus melphalan. RESULTS: As compared to 4-year results, the 6-year probabilities of relapse-free survival, freedom from progression and overall survival were almost superimposable. In fact, during the two additional years elapsed since prior survey, only one event occurred (fatal cerebral hemorrhage) that was unrelated to Hodgkin's disease. In particular, the proportion of patients remaining event-free was 78% for those with short initial complete response and 31% for patients who had failed initial MOPP/ABVD. According to previous experience, both groups have a very low or no chance of long-term event-free survival when treated with standard-dose salvage chemotherapy. CONCLUSIONS: The very favorable long-term results of the high-dose sequential regimen together with its excellent tolerability and lack of early or late fatal toxicities, will assist clinicians in defining optimal timing for high-dose therapy in the management of Hodgkin's disease. According to a revised cost/benefit analysis, it would appear that, at present, the best timing of high-dose sequential therapy in patients failing MOPP/ABVD is at first early relapse.

Actuarial Analysis↗
PubMed1992

Beta-blocking effect of propafenone based on spectral analysis of heart rate variability.

RR variability was analyzed in 15 patients with ventricular arrhythmias to evaluate whether the antiarrhythmic action of propafenone is associated with alteration of neural control mechanisms. Before drug administration, spectral analysis of RR variability was characterized by 2 major components at low and high frequency, which are considered to reflect sympathetic and parasympathetic modulation of the heart period. After propafenone (600 to 900 mg/day), there was a marked reduction in RR variance (826 +/- 184 to 412 +/- 77 ms2; p < 0.05), although the mean RR interval was unchanged. The drug significantly reduced the low-frequency component (52 +/- 6 to 28 +/- 4 nu) and augmented the high-frequency component (39 +/- 6 to 55 +/- 5 nu). As a result, the low-/high-frequency ratio (an index of sympathovagal balance) decreased from 2.0 +/- 0.4 to 0.6 +/- 0.1. A positive correlation between serum levels and drug-induced changes in the low-frequency component was also observed. Furthermore, the increase in the low-frequency component induced by tilt (53 +/- 5 to 79 +/- 3 nu) was markedly attenuated after drug administration (27 +/- 5 to 54 +/- 7 nu). Thus, propafenone administration is associated with changes in spectral components that are consistent with a beta-blocking effect of the drug.

Adrenergic beta-Antagonists↗
PubMed1992

High-performance liquid chromatographic determination of rufloxacin and its main active metabolite in biological fluids.

A high-performance liquid chromatographic method is described for the determination of a fluoroquinolone, rufloxacin, and its N-desmethyl metabolite in plasma, urine and bile. Samples are chromatographed on a poly(styrene-divinylbenzene) column, the eluate being monitored with a fluorescence detector. The method was validated and a detection limit of 10 ng/ml for both rufloxacin and its metabolite in all the biological matrices considered was found. The method was successfully applied in pharmacokinetic studies.

Anti-Infective Agents↗
PubMed1992

Circadian variation of spectral indices of heart rate variability after myocardial infarction.

The circadian variations of spectral indices of heart rate variability were analyzed in 20 patients 4 weeks after a first and uncomplicated myocardial infarction (MI) and in 20 control subjects. R-R interval and variance showed a characteristic day-night pattern with a significant reduction of the latter parameter in patients after MI (10,967 +/- 1109 msec2 vs 16,860 +/- 2132 msec2). Control subjects were characterized by a predominance of low-frequency (approximately 0.1 Hz) component during the day and of high-frequency (approximately 0.25 Hz) component during the night, which reflected the expected 24-hour pattern of variation of sympatho-vagal balance. A 24-hour elevation (64 +/- 3 normalized units [nu] vs 56 +/- 2 nu; p less than 0.05) of the low-frequency component and a smaller (23 +/- 2 nu vs 32 +/- 2 nu; p less than 0.05) high-frequency component during the night differentiated patients after MI from subjects. The difference between the two groups was even more evident when the 24-hour sympatho-vagal balance was assessed with the low frequency/high frequency ratio. Thus spectral analysis of heart rate variability indicates that in patients after MI there is an alteration of neural control mechanisms as indicated by the presence of signs of sympathetic activation and by the attenuation of the nocturnal increase in vagal tone.

Aged↗
PubMed1992

Spectral analysis of sympathetic discharge, R-R interval and systolic arterial pressure in decerebrate cats.

In 19 decerebrate and artificially ventilated cats, we analyzed, with a power spectral methodology, the variability simultaneously present in R-R interval and in thoracic preganglionic sympathetic outflow. R-R interval was characterized, as already described in humans and other experimental preparations, by two rhythmic components occurring at a frequency of about 0.1 Hz (low-frequency, LF) and at one corresponding to respiratory rate (high-frequency, HF) which, in these experiments, was set at 0.32 Hz. Two similar rhythmic components were also present in the sympathetic discharge. Arterial pressure changes were produced by aorta or vena cava flow obstruction in order to produce reflex responses in sympathetic activity. Reflex sympathetic excitations induced an increase in the LF component of both R-R interval and sympathetic discharge variabilities, while the HF components were simultaneously reduced. In contrast, reflex sympathetic inhibitions were accompanied by a decrease in LF components of both variability signals, while the HF components were simultaneously increased. A significant and positive correlation was found between changes in impulse activity and the amplitude of LF component of either R-R interval or sympathetic discharge variabilities. These data support the hypothesis that the low-frequency component of R-R variability can be used as a marker of sympathetic modulation.

Animals↗