Biomedical subjects

F Colombo

Publications and source records attributed to F Colombo.

At least 73 records · Page 4Linked to original sources

PubMed1993

Time dependence of residual tissue viability after myocardial infarction assessed by [18F]fluorodeoxyglucose and positron emission tomography.

Areas of myocardial infarction may retain glycolytic activity and this finding is indicative of tissue viability and predictive of functional recovery after revascularization. In order to assess the relation between the time elapsed from the occurrence of acute myocardial infarction and persistence of myocardial metabolic activity in the infarcted tissue, we prospectively studied 65 patients with previous myocardial infarction diagnosed clinically and by electrocardiographic (Q wave) and enzymatic criteria. All patients underwent coronary angiography and contrast left ventriculography, evaluation of regional myocardial glucose metabolism (in the fasting state) by positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG), and assessment of myocardial perfusion by single photon emission computed tomography (SPECT) with technetium-99m methoxyisobutyl isonitrile (99mTc-MIBI). Based on the regional metabolic and perfusion findings, patients were divided into 2 groups, depending on the absence (group 1, 26 patients) or presence (group 2, 39 patients) of [18F]FDG uptake in the underperfused regions. Areas of underperfusion at rest, consistent with the clinically identified myocardial infarction site, were observed in all patients. Severity of coronary artery disease, presence of collaterals, number of hypocontractile segments, and wall motion score did not differ significantly in the 2 groups. The time elapsed from the infarction was significantly greater (1,860 +/- 1,333 days) in group 1 than in group 2 (92 +/- 115 days; p < 0.0001). Exercise caused an increase in severity and/or extent of resting perfusion abnormalities in a greater proportion of patients of group 1 (53% vs 23%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Analysis of dosimetric measurements in linac radiosurgery calibration.

The aim of this paper is to analyse the dosimetric parameters of a linear accelerator used in radiosurgery treatments. The influence of these parameters on the resulting dose distribution are basic for delivering the predefined dose to the vascular or oncological target volume. Several dosimetric methods have been used to define the output factors for small fields. The thimble and the Markus chambers, TLD and film dosimetry are investigated; all these dosimetric systems give reliable and almost similar results if used in the correct way. In the determination of tissue maximum ratio (TMR) the response curves obtained by ionometric and film dosimetry were investigated. For TMR determination the use of the Markus chamber and the correction factors to be applied as a result of the small dimension of the field were also investigated.

Calibration↗

PubMed1993

From radiotherapy to stereotactic radiosurgery: physical and dosimetrical considerations.

The aim of this presentation is to analyse the mechanical and dosimetrical parameters of the linear accelerator used in stereotactic radiosurgery. The use of the thimble and Markus chambers, TL and film in small field dosimetry are investigated. To determine the optimal irradiation technique and dose distribution, the dose volume to healthy tissue is considered.

Humans↗

PubMed1993

Is there still an avoidable fraction of post-operative thromboembolic complications with heparin prophylaxis? The results of a case-control surveillance. Collaborative Group on Heparin Prophylaxis in Surgery (S.E.P.E.C.).

A case-control multicenter study was set up in 68 general and specialistic wards in Italian regional hospitals in order to assess whether underuse of heparin prophylaxis may account for at least a fraction of the thromboembolic events still occurring in surgical patients. 100 cases with clinically relevant thromboembolic or hemorrhagic events occurring during hospitalization for major surgery and 200 controls were identified. Controls were selected among patients not presenting any of the events under study during the same period of observation and were matched with cases for age, sex, and type of surgery. The results of the study suggest that heparin use in routine conditions of care closely reflects the "consensus" knowledge, patients at higher risk (specifically orthopedic surgical patients, those with varicose veins or with preoperative bed rest longer than 3 days) being treated more frequently with heparin. Absence of heparin prophylaxis does not appear to represent a specific risk factor for the occurrence of index events (OR 0.73, 95% CI = 0.42-1.26). Despite the higher rates of heparin exposure, the presence of varicose veins is associated with a statistically significant increase in the risk of postoperative complications (OR 2.23, 95% CI = 1.07-4.65). This study indicates that among known pre- and peri-operative risk factors only varicose veins may be unprotected by the current prophylaxis practice.

Adult↗

PubMed1993

[Anatomo-functional changes in the prostate and seminal vesicles with aging].

The anatomo-functional modifications of the prostate and the seminal pathways during the genital apparatus aging, (prostatic hyperplasia and hypotrophy of the seminal pathways and testis), are caused by hormonal modifications (inconstant increase of the gonadotropins LH-FSH, decrease of the peripheric utilization of testosterone, alterations of the adrenal secretion), by anatomical involutions (degenerations of the glandular, stromal and vascular components).

Aged↗

PubMed1993

Repair of a recurrent urethrovaginal fistula with an island bulbocavernous musculocutaneous flap.

This paper describes a case of recurrent postpartum urethrovaginal fistula. The extent of the vaginal tissue loss and the perilesional scarring made direct closure of the defect not practicable. After suturing of the urethra, the anterior vaginal wall was reconstructed with an island bulbocavernous musculocutaneous flap raised from the left labium majus. Seven months after surgery, the flap healed well, and cystography showed a regular voiding without periurethral suffusions. Healing of thedonor site also was aesthetically satisfactory.

Adult↗

PubMed1993

[Changes in sexuality and fertility in the elderly: ejaculation].

After the remark of the own results on an epidemiological research about andropausal sexual problems, the Authors analyze the alterations of ejaculatory mechanism with elderly, focusing frequency and etiopathogenesis. They underline the need of prevention of ejaculatory disturbances deriving from chronic disease or of iatrogenic origin.

Aged↗

PubMed1993

[Andrologic problems in prostatic carcinoma].

In our opinion, the attempt to save the sexuality and the erectile ability in a patient with a prostate cancer, in the respect of an absolute oncological radicality, should be recommended since potency represents for the patient a primary aspect in the quality of residual life. At the Institute of Urology of the University of Milan a study to identify pathogenetic mechanisms leading to erectile failure in the various phases of a prostate cancer was performed. From January 1988 to December 1993, 36 patients (range 50-60 years old) suffering from prostate cancer B1 stage (14 pts), B2 (20 pts) and C (2 pts) underwent to radical prostatectomy. Out of 24 pts reporting erectile ability before surgery, 10 was in B1 stage and underwent monolateral nerve-sparing technique. Out of these, 6 pts (60%) maintained the erection after the operation. The treatment with LHRH analogues weighted on loss of libido and erectile and erectile potent due to central androgenic delete. At our Institute 87 pts in treatment with LHRH analogues reported loss of erection in 80% of cases. In this group 22 underwent to an andrological examination. The exams (Dynamic penile Doppler, Dynamic Cavernosometry and stimulating test with intracavernous vasoactive drugs) confirm the absence of peripherical damages in the pathogenesis of the erectile dysfunction. Patient underwent radiotherapy develop a secondary impotence due to an obliterant progressive angioitis in a percentage ranging from 30 to 80%.(ABSTRACT TRUNCATED AT 250 WORDS)

Erectile Dysfunction↗

PubMed1993

Bulbocavernous myocutaneous flap: a new technique in repair of recurrent urethrovaginal fistula.

This paper describes the case of a recurrent post-partum urethrovaginal fistula. The extent of the vaginal tissues loss and the perilesional scarring made the direct closure of the defect non practicable. After suturing the urethra, the anterior vaginal wall was reconstructed with an island bulbocavernous musculocutaneous flap raised from the left labium majus. Nineteen months after surgery the flap healed well without peri urethral suffusion.

Adult↗

PubMed1993

Our treatment of congenital complicated penile deviations.

Congenital anomalies of the penis expressed in various forms of flexures can be associated to a rotation of the shaft. An asymmetrical insertion of the suspensory ligament on the dorsal surface of the tunica albuginea often accounts for corporal rotation. This distorts the spatial relationship between the corpora cavernosa and the pubic bone. The two corpora may overlap and the shaft is partially rotated. For the surgical treatment of these defects we proposed (1989) a technique of contrarotation of the tunica albuginea which was later abandoned because it was too invasive. We developed a technique based on the ipsilateral re-suspension of the suspensory ligament of the penis between the tunica of the lower corpus and the pubic symphysis to restore the true axis. The neurovascular adnexa, the corpora cavernosa, and the corpus spongiosum remain untouched.

Follow-Up Studies↗

PubMed1993

[Seminal changes of inflammatory origin].

Presence of bacteria in the sperm is often associated to a reduction of fertility in relationship with a decrease in number and motility of spermatozoa and with an augmentation of the abnormal spermatic cells. Clinical features of seminal phlogosis are extremely variable both in acute and chronic evolutions. In every case the first diagnostical step is sperm count and seminal complete analysis which can give evidence of phlogistic alteration in quantity and quality of spermatic cells with a typical presence of an excess in white blood cells (leucospermia) as consequence of infection. The great variety in clinical and bacteriological aspects and the particular biological features of the organs involved, as the prostate, make treatment a difficult problem to solve with particular regard to the choice of an effective antibiotic which pharmacokinetic has to result suitable for the microorganism as well as for the tissue of the infection site. All those efforts are indispensable to reduce the too frequent therapeutical failures in the management of seminal phlogistic pathology with complications of organic but also pathological relevancy for the patient and the partner too.

Anti-Bacterial Agents↗

PubMed1993

Measurement of regional cerebral glucose utilization with fluorine-18-FDG and PET in heterogeneous tissues: theoretical considerations and practical procedure.

Functional tissue heterogeneity, i.e., inclusion of tissues with different rates of blood flow and metabolism within a single region of interest, is an unavoidable problem with PET. Errors in determination of regional cerebral glucose utilization (rCMRglc) with [18F]FDG have resulted from the currently used simplifying assumption that all regions examined are homogeneous. We have established an optimal, yet practical procedure to minimize errors due to tissue heterogeneity in determination of rCMRglc. Effects of applying the three-rate constant kinetic model designed for homogeneous tissues with both dynamic and single-scan procedures and the Patlak plot were evaluated in normal subjects in experimental periods up to 120 min following tracer injection. The procedure with a single scan carried out any time within the interval between 60 and 120 min following tracer injection, combined with population average rate constants determined over a 120-min period, was found to be optimal for quantitative rCMRglc studies.

Adult↗

PubMed1992

Errors introduced by tissue heterogeneity in estimation of local cerebral glucose utilization with current kinetic models of the [18F]fluorodeoxyglucose method.

The effects of tissue heterogeneity on the estimation of regional cerebral glucose utilization (rCMRglc) in normal humans with [18F]2-fluoro-2-deoxy-D-glucose ([18F]FDG) and positron emission tomography (PET) were compared with respect to the various kinetic models of the [18F]FDG method. The kinetic models were conventional homogeneous tissue models of the [18F]FDG method, with (4K Model) and without (3K Model) a rate constant to account for an apparent loss of [18F]2-fluoro-2-deoxy-D-glucose-6-phosphate ([18F]FDG-6-P), and a tissue heterogeneity model (TH Model). When either of the kinetic models designed for homogeneous tissues was applied to heterogeneous tissues, estimates of the rate constant for efflux of [18F]FDG from the tissue (k2*) and of the rate constant for phosphorylation of [18F]FDG (k3*) decreased as the duration of the experimental period was increased. When the 4K Model was used, estimates of the rate constant for the apparent dephosphorylation of [18F]FDG-6-P (k4*) were significantly greater than zero and fell with increasing duration of the experimental period. Although the TH Model included no term to describe an apparent dephosphorylation of [18F]FDG-6-P, the fit of the TH Model to the time course of total tissue radioactivity was at least as good as and often better than the fit of the 4K Model in the 120-min period following the pulse of [18F]FDG. Hence, the high estimates of k4* found in PET studies of less than or equal to 120 min can be explained as the consequence of measuring radioactivity in a heterogeneous tissue and applying a model designed for a homogeneous tissue; there remains no evidence of significant dephosphorylation of [18F]FDG-6-P in this time period. Furthermore, use of the 4K Model led to an overestimation of rCMRglc; whole-brain glucose utilization calculated with the 4K Model was greater than 20% higher than values usually obtained in normal humans by the model-independent Kety-Schmidt technique. rCMRglc was accurately estimated by the TH Model and, in experimental periods sufficiently long to minimize the effects of tissue heterogeneity, also by the original 3K Model of the deoxyglucose method.

Adult↗

PubMed1992

Metabolic impairment in human amnesia: a PET study of memory networks.

Human amnesia is a clinical syndrome exhibiting the failure to recall past events and to learn new information. Its "pure" form, characterized by a selective impairment of long-term memory without any disorder of general intelligence or other cognitive functions, has been associated with lesions localized within Papez's circuit and some connected areas. Thus, amnesia could be due to a functional disconnection between components of this or other neural structures involved in long-term learning and retention. To test this hypothesis, we measured regional cerebral metabolism with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) and positron emission tomography (PET) in 11 patients with "pure" amnesia. A significant bilateral reduction in metabolism in a number of interconnected cerebral regions (hippocampal formation, thalamus, cingulate gyrus, and frontal basal cortex) was found in the amnesic patients in comparison with normal controls. The metabolic impairment did not correspond to alterations in structural anatomy as assessed by magnetic resonance imaging (MRI). These results are the first in vivo evidence for the role of a functional network as a basis of human memory.

Adult↗

PubMed1992

Prevalence and variability of orthostatic hypotension in the elderly. Results of the 'Italian study on blood pressure in the elderly (SPAA)'. The 'Gruppo di Studio Sulla Pressione Arteriosa nell'Anziano'.

The prevalence of orthostatic hypotension (OH) in an elderly outpatient population was assessed according to the most common criteria given in the literature. Short-term OH variability and relationships between OH and its known risk factors were also analysed. A sample of 3858 elderly outpatients aged 65 years or more was randomly recruited by 444 Italian general practitioners. The patients' blood pressure (BP) and heart rate were recorded in both lying and standing positions at two visits 7 days apart. Three definitions were used for the identification of OH: (1) a decrease in systolic BP greater than 20 mmHg (SOH); (2) a decrease in both systolic (greater than 20 mmHg) and diastolic (greater than 10 mmHg) BP (SDOH); (3) any decrease in systolic BP associated with symptoms (SyOH). Prevalence figures for SOH were 13.8% at the first and 12.6% at the second visit, and respectively 5.3 and 4.8% for SDOH, 14.1 and 11.8% for SyOH. All the criteria were met by less than 2% of subjects at each visit. The diagnosis of OH was confirmed at both visits in 36.3% of cases for SOH, in 25.7% for SDOH, and in 43.9% for SyOH. Each different OH definition identifies a population subgroup characterized by different sets of risk-factors. The presence and prevalence of OH is difficult to define because different people may be identified by the currently accepted criteria or by the same criterion over a short time.

Aged↗

PubMed1992

Venous surgery in erectile dysfunction: therapeutic strategy and results.

The therapeutic rationale of venous surgery is to create an effective obstacle to the pathologically increased venous outflow, determined by an intrinsic pathology of the cavernous bodies. In the last 15 years, many techniques have been proposed, and our therapeutic approach has evolved with our knowledge of penile haemodynamics. Up to October 1990, we performed 316 operations for the relief of impotence. In a 2-year follow-up our recurrence rates were as follows: DDV plus corporpexy (n = 50): 26% (n = 13); DDV plus crura plication (n = 34): 47% (n = 16); DDV plus collateral vein ligation (n = 48): 62.5% (n = 30).

Arterial Occlusive Diseases↗

PubMed1992

Prognostic significance of prostate-specific antigen in endocrine treatment for prostatic carcinoma.

We have studied the prognostic significance of prostate-specific antigen (PSA), monitored monthly, in 24 patients with prostatic cancer (5 D1, 19 D2) on endocrine therapy. The pretreatment levels of PSA were high in all patients (mean value 41 ng/ml). It was found that PSA levels at the end of the first and sixth months of treatment were reliable prognostic indicators. At the first month evaluation PSA had decreased more than 50% from the initial values in the 16 patients with stable disease, while it had decreased less than 50% in those with progressing disease. At the end of 6 months, patients with stable disease had PSA levels within the normal range, while 8 of the patients who had progressing disease had levels higher than 10 ng/ml. Respectively 6 and 2 patients had also had increases in PSA levels at 3 and 6 months before scintigraphic demonstration of increased bone metastases.

Aged↗

PubMed1992

Efficacy and tolerability of medium-term treatment with simvastatin in primary hypercholesterolaemia.

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, a new class of hypolipidaemic agents, have been recently shown to be effective in lowering both total and low-density lipoprotein (LDL)-cholesterol. In the present study 20 patients were treated with simvastatin for six months. Various dosing regimens of 10, 20, and 40 mg/day were employed. Administration of simvastatin 10 to 40 mg/day resulted in a 24.7 to 35.8% reduction in LDL-cholesterol levels and in a 19.5 to 26.9% decrease of total cholesterol levels. Moreover, simvastatin increased high-density lipoprotein-cholesterol and induced a decrease in plasma triglycerides. The side-effect profile was similar to other observations and included reversible transaminase elevations, myalgia and gastrointestinal complaints. From the present study simvastatin seems to be well tolerated in the short- to medium-term and to be effective; however, its long-term tolerability needs to be confirmed.

Adult↗