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Biomedical subjects

R Colombo

Publications and source records attributed to R Colombo.

At least 109 records · Page 6Linked to original sources
PubMed1992

Transrectal microwave hyperthermia for benign prostatic hyperplasia: long-term clinical, pathological and ultrastructural patterns.

Transrectal microwave hyperthermia of the prostate was administered to 191 patients with bladder outlet obstruction due to benign prostatic hyperplasia who were either at poor operative risk or who refused surgery. Patients were divided in 2 groups according to age and they underwent either 5 or 10, 60-minute sessions of hyperthermia, with a calculated intraprostatic temperature of 42.5 plus or minus 0.5C. Light and electron microscopy showed no irreversible damage at the glandular epithelium but did demonstrate a significant increase in neoformed intraprostatic capillary-like vessels. At 1, 12 and 24 months residual urine volume was significantly decreased in the majority of patients but only a minor amelioration of urinary flow rates and subjective symptoms was observed. According to maximum flow nomograms all patients were still obstructed postoperatively. Transrectal hyperthermia cannot be considered a genuine alternative to surgery for patients with bladder outlet obstruction due to benign prostatic hyperplasia.

Aged↗
PubMed1992

Transrectal microwave hyperthermia for advanced prostate cancer: long-term clinical results.

Transrectal microwave hyperthermia was applied to 46 stages D1 and D2 prostate cancer patients to treat urinary symptoms and local pain unrelieved by total androgen ablation therapy. Hyperthermia was administered in 10, 60-minute sessions twice a week for 5 weeks. A calculated intraprostatic temperature of 43.5 +/- 0.5C was maintained throughout the treatment. At 2 years the mean residual urine volume was significantly decreased (p less than 0.05), while the mean peak flow rate and maximum flow nomogram were improved but not significantly. The majority of patients reported a notable amelioration of subjective symptoms and quality of life. The only complication was a prostatorectal fistula that was cured by leaving a urethral catheter in place for 4 weeks. Prostatic hyperthermia is a safe and effective palliative procedure for bladder outlet obstruction due to advanced prostate cancer.

Aged↗
PubMed1992

Short time treatment with high-efficiency paired filtration dialysis for chronic renal failure.

With the aim of treating with short sessions even chronic uremic patients with cardiovascular instability, we have developed our previous findings about paired filtration dialysis (hemofiltration-hemodialysis in series) by a method we call high-efficiency paired filtration dialysis (HEPFD). We have treated with this method for 6 months 6 chronic anuric uremic patients previously treated for 6 months with hemofiltration (HF) because of their cardiovascular instability. By comparison with HF, HEPFD shows much higher clearances of small molecules with consequent significant decrease of their predialytic values, improvement of Kt/V value, lower beta 2-microglobulin clearance (its predialytic value remains unchanged), and the same tolerability. HEPFD allows short, efficient, and well-tolerated treatments even in patients with cardiovascular instability.

Adult↗
PubMed1992

Plasma lipids and fatty acid levels in chronically uremic patients undergoing blood purification with different methods.

Levels of plasma lipids and the fatty acid composition of major plasma lipid classes have been determined in chronically uremic patients before and after treatments with hemofiltration, high efficiency paired filtration dialysis, or acetate-free biofiltration. The major findings are a decrease of triglycerides and an increase of total free fatty acids (FFAs) at the end of the dialytic session--already reported in the literature--that do not appear to be strictly dependent on heparin administration. The changes in the plasma concentrations of selected saturated and polyunsaturated fatty acids, which may contribute to alteration of functional parameters in the cardiovascular system in dialyzed patients, are different in the various types of techniques.

Adult↗
PubMed1992

Transrectal hyperthermia-induced histological and ultrastructural changes of human benign prostatic hyperplasia tissue.

This prospective study evaluated the tissutal, cellular and intracellular effects of transrectal microwave hyperthermia on human benign prostatic hyperplasia. Forty-eight patients with benign prostatic hyperplasia underwent ten 60-min-long sessions of transrectal hyperthermia with an intraprostatic calculated temperature of 42 +/- 0.5 degrees C. Ultrasound-guided transperineal biopsies of the prostate were taken before and 1 month after completion of treatment. Postoperatively, morphometric analysis of bioptic specimens showed a statistically significant (p < 0.01) increase in the number of intraprostatic arterioles and capillary-like vessels. Diffused inflammatory infiltrates were also noted. Postoperative integrity of intracellular organelles and cellular membranes was evidenced by transmission electron microscopy. Our regimen of transrectal prostatic hyperthermia did not cause any irreversible histological or ultrastructural damage to the prostatic tissue. Hyperthermia-induced increase in blood flow could enhance drug delivery to the prostate gland.

Humans↗
PubMed1992

Long-term adaptation of 24-h heart rate variability after myocardial infarction. The EAMI Study Group. Exercise Training in Anterior Myocardial Infarction.

To investigate the effects of physical training on neurovegetative profile of patients with previous anterior myocardial infarction (MI), we studied 38 patients out of the EAMI study at 4 to 6 weeks after anterior MI (test 1), who were then assigned randomly to a training group (n = 22) or to a control group (n = 16) and studied again 6 months later (test 2). Neurovegetative function was assessed by analyzing the heart rate variability (HRV) of 24 h, from ambulatory ECG recording, both in time domain, as standard deviation of sinus rhythm RR intervals (sdRR) and percentage of differences greater than 50 ms for successive sinus rhythm R-R intervals (pNN50), and in frequency domain, as low frequency (LF) and high frequency (HF) components of RR variability power spectrum. At test 1, HRV was almost in normal range or slightly decreased in few subjects. HRV increased on average at test 2: sdRR augmented significantly (p less than 0.05) without significant differences between training group and control group; mean LF/HF ratio increased slightly (p less than 0.05) at test 2. This might suggest a shift of neurovegetative balance toward a sympathetic rule, but the difference is too small and the patient population limited to reach firm conclusions. Analysis of 24-h dynamics of HRV in single patients showed different patterns and different adaptations during the time course of 6 months after anterior MI.

Adaptation, Physiological↗
PubMed1991

Effects of lithium ions on actin polymerization in the presence of magnesium ions.

In spite of the abundant literature, questions on the biological action of Li+ are far from being answered. In the present paper we demonstrate that modification of the salt composition of the medium for actin polymerization, by gradually replacing K+ with Li+, leads to a dose-related change in the time course of actin assembly. The presence of Li+ influences actin polymerization in vitro by enhancing nucleation and decreasing critical monomer concentration at steady state. Furthermore, Li+ stabilizes actin polymers mainly by lowering the absolute value of the dissociation rate constant (K-) and shifting (towards lower values of actin monomer concentrations) the range of G-actin concentrations in which filament-subunit flux can occur. The influence of Li+ on actin and tubulin polymerization in vitro suggests that cytoskeletal structures could be some of the cytoplasmic targets of this ion.

Actins↗
PubMed1991

Lithium increases actin polymerization rates by enhancing the nucleation step.

Lithium affects the polymerization mechanism of some cytoskeletal proteins in vitro, so its biological activity could also reflect lithium influence on assembly processes. Our data demonstrate that lithium nucleates actin polymerization and, in parallel, is less effective in the elongation step. Furthermore, falling-ball and fluorimetric tests suggested that lithium-induced actin polymers at steady-state are shorter than K(+)-polymerized actin filamentous structures. The lithium-induced actin assembly seems to follow the "reversible polymerization model" and the critical concentration of Li(+)-assembled actin at steady-state is markedly lower than that of sister actin samples polymerized by potassium chloride. Finally, the stabilization of actin nuclei induced by lithium ions could be related to their effect of lowering the dissociation rate constant.

Actin Cytoskeleton↗
PubMed1991

Multimodal therapy for stones in pelvic kidneys.

Stones located in pelvic kidneys can be successfully treated by extracorporeal lithotripsy, either alone or in combination with endourology and open surgery. A multimodal approach was used in 16 patients with pelvic kidney stone disease and a 87.5% stone-free rate was achieved. The proper positioning of the patient on the lithotripter apparatus and the correct integration of the different therapeutic procedures were the real clues for obtaining a remarkable success rate with a minimally invasive approach.

Adult↗
PubMed1991

Combined intravesical chemotherapy with mitomycin C and local bladder microwave-induced hyperthermia as a preoperative therapy for superficial bladder tumors. A preliminary clinical study.

Twelve patients suffering from superficial transitional cell carcinoma of the bladder underwent treatment combining simultaneous mitomycin C topical instillation and local endocavitary hyperthermia as a preoperative adjunct to transurethral resection in a preliminary clinical study. A specifically designed system to deliver and monitor local bladder hyperthermia was used. The feasibility, the subjective tolerance and the side effects of the combined treatment were the main target of our investigation. Endoscopic and histologic features, assessed before, during and after this combined approach, showed selective damage to neoplastic areas with minimal changes in the normal urothelium. Local intravesical concurrent chemotherapy and hyperthermia administration is found to be a safe and well-tolerated approach for superficial bladder tumor treatment. The preliminary results encourage further studies to define the limits and prospects of this regimen, in both superficial bladder tumor ablation and prophylaxis of recurrences.

Administration, Intravesical↗
PubMed1991

Long term experience with the prostatic spiral for urinary retention due to benign prostatic hyperplasia.

Twenty high risk patients with benign prostatic hyperplasia and urinary retention were treated by insertion of an intraprostatic spiral. The device was positioned under fluoroscopic guidance using a technique developed by us. The procedure required only local anaesthesia and successfully relieved the obstruction in all patients. At the six-month follow-up full continence had been achieved in 15 patients (75%). Three patients (15%) complained of mild stress incontinence but this was not severe enough to require removal and repositioning of the spiral. A 92-year-old patient reported severe incontinence despite correct positioning of the spiral. Removal of the spiral was necessary in one of the continent patients who was receiving anti-coagulant drugs because of sudden, severe macrohaematuria with subsequent acute urinary retention. The spiral became displaced and required repositioning in one patient. Median residual urine volume was constantly lower than 50 ml and the median maximal flow rate at six-month follow-up was 13.2 ml/s. Our long term follow-up study shows the effectiveness and safety of the prostatic spiral as an alternative treatment for selected patients with urinary retention caused by benign prostatic hyperplasia.

Aged↗
PubMed1991

In-vitro susceptibility of Haemophilus influenzae to loracarbef (LY 163892) and other oral antibiotics. Collaborative Study Group on Pediatric Infectious Disease in Lombardy.

Data on susceptibility of Haemophilus influenzae are scanty in Italy. We compared the activity of loracarbef (Ly 163892), a new carbacephem, with that of 4 other agents against 265 strains of H. influenzae (46 type b, 219 nontypable) isolated from adults and children at Istituti Clinici di Perfezionamento of Milano, between 1/1/84 and 1/1/89, and also from 7 children at pediatric departments in Lombardy during 1988. In adults 72 strains were all isolated from sputum of patients with pneumonia or chronic bronchitis; in children 199 strains were isolated from conjunctiva (53% of the patients had also a concomitant respiratory infection), 24 from middle ear, 18 from sputum and 32 from blood or cerebrospinal fluid. Minimal inhibiting concentrations (MIC) were determined by the broth microdilution technique. The incidence of resistance of H. influenzae to ampicillin was 3.8%; the lowest percentage of resistance was found for loracarbef (0%) and the highest for erythromycin (94% for strains isolated from children and 97% for strains isolated from adults).

Adult↗
PubMed1991

Renal lithium clearance in the different stages of hypertension.

This study investigated whether fractional lithium excretion (FELi), used as a marker of proximal fluid delivery, changes during different phases of essential hypertension. Forty-eight subjects were studied: 12 essential hypertensives (EH); 12 borderline hypertensives (BL); 12 normotensives with a positive family history of essential hypertension (NH) and 12 normotensives without a family history of essential hypertension (NN). Measurements were performed in the recumbent position, both in basal conditions and after a saline load (2% body weight in 1 h; 0.333 ml/min per kg body weight). In basal conditions, a moderate extracellular volume expansion was already present in the subjects. In these conditions, FELi of EH was significantly higher than that of all the other groups (P less than 0.01). After the saline load, fractional sodium excretion increased in all the groups (P less than 0.01), but to a significantly greater extent in EH (P less than 0.01). FELi rose significantly only in BL (P less than 0.05). The change in FELi of BL correlated positively (P less than 0.02) with the change in blood pressure in 10 of these subjects 3 years after this study. Moderate extracellular volume expansion may be able to either reveal or stimulate an increase of FELi in subjects with established hypertension. When a greater degree of extracellular volume expansion is induced, this increases FELi in BL and this effect may be related to the subsequent development of hypertension.

Adolescent↗
PubMed1991

[Comparison of rectal examination, transrectal echography, CAT and MRI in the local staging of prostatic carcinoma].

From January 1978 to June 1990, 120 prostate cancer patients were submitted to radical retropubic prostatectomy. Local pathological staging evidenced 70 patients (58%) in stage B of disease (intraprostatic disease) and 50 patients (42%) in stage C of disease (extraprostatic disease). Sensitivity of rectal examination, transrectal ultrasonography, CT or NMR for stage B was 61%, 75%, 54% respectively and for stage C 61%, 70%, 50%. This study underscores the effectiveness of transrectal ultrasonography in the diagnosis of prostate cancer non evidenced at rectal examination. CT and NMR are not valuable for local staging and are now used only in patients at risk for extraprostatic or systemic disease.

Evaluation Studies as Topic↗
PubMed1990

[Local prostatic hyperthermia in the therapy of urinary obstruction caused by prostatic adenoma. Experimental, clinico histologic and structural findings].

A specifically designed system of selective prostate heating was used to treat 197 patients with prostatic diseases: 164 benign prostatic hypertrophy cases, 14 prostatic adenocarcinoma cases, 19 chronic abacterial prostatitis cases. Ninety-one benign prostatic hypertrophy patients could be evaluated at the three month follow-up date. Sixty-eight patients complained of severe obstructive symptoms and 23 had an indwelling catheter. Prostates were heated up to 42 +/- 0.5 degrees C during 60 minute long sessions, once or twice a week for five weeks. Local prostatic hyperthermia determined a marked amelioration of the clinical picture in 67% of patients who presented without an indwelling catheter. Sixteen patients (70%) were weaned off the catheter. Major complications were not encountered.

Aged↗
PubMed1990

Morphodynamic and biochemical assessment of seminal plasma in patients who underwent local prostatic hyperthermia.

Fourteen young and sexually active patients with chronic abacterial prostatitis who failed to respond to conventional medical therapy underwent four 60 minute sessions of local prostatic hyperthermia. Calculated prostatic temperature was 42 +/- 0.5 degrees C. Analysis of seminal plasma was performed pre- and postoperatively and included: number, motility, and morphology of spermatozoa; zinc, citric acid, D-fructose, and free testosterone content. Preoperative semen analysis was normal in five patients and abnormal in nine. Morphodynamic and biochemical patterns of seminal plasma were not significantly altered by thermotherapy. Local prostatic hyperthermia can be safely used in patients with chronic abacterial prostatis not responding to conventional medical therapy and desiring to preserve their reproductive potential.

Adult↗