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Biomedical subjects

F Colombo

Publications and source records attributed to F Colombo.

At least 109 records · Page 6Linked to original sources
PubMed1991

Pressure monitoring inside Meckel's cave during percutaneous microcompression of gasserian ganglion.

During percutaneous microcompression of the gasserian ganglion for the relief of trigeminal neuralgia, a computerized technique for monitoring the pressure inside Meckel's cave was employed in 22 patients. A dedicated transducer connected to a computer records the balloon inflation pressure. Its variations are discernible within tenths of a bar and are plotted in relation to time. The intraoperative pressure inside Meckel's cave is from 0.9 to 2.4 bars. When pressure was low, there was recurrence of pain. The highest values of pressure (1.9-2.4 bars) were observed in most of the patients suffering from untoward side effects. The clinical results seem to be influenced by the level of the intraoperative intracavitary pressure.

Aged↗
PubMed1991

Brain stem acoustic evoked potentials recorded from the human mesencephalon.

Near field brain stem evoked potentials (NF-BAEPs) were recorded by means of an intraparenchymatous electrode placed in the right mesencephalon, during a stereotactic-guided biopsy of a tumor. The traces were compared with far field BAEPs (FF-BAEPs) obtained intraoperatively with scalp electrodes. The findings suggest a peripheral origin of wave II, a bilateral source of wave III and a main contralateral source of wave IV, while wave V seems to take origin mainly from the homolateral upper brain stem. Some intraparenchymatous activities do not project to the scalp. The possible impairments of NF-BAEP due to the presence of the tumor and the challenges of unidimensional single electrode recording are discussed.

Acoustic Stimulation↗
PubMed1991

[Early diagnosis and correct treatment of cryptorchism].

Diagnosis in cryptorchidism should be as early as possible for therapeutical purposes and for the achievement of most positive results. Early but also exact diagnosis allows a selective therapy concerning type of procedure and age of performance. Aims of early diagnosis and selected treatment are: prevention of infertility and eventual decrease of androgenic endocrinal function in the adult; prevention of torsion in retractile testis; prevention of trauma in perineal ectopic situation; prevention of cancer especially in cryptorchidism of the adult; prevention of psychogenic defects of the empty scrotum. Those goals can be obtained by different approaches: pharmacological (hormonal stimulation), surgical (orchidopexy) or by their association. If hormonal administration is not suitable or without results surgical approach will be adopted. Which is now the most suitable age for surgery? Testicular damages begin at the second year of life. Therefore operation should be acted in advance. However, up to date international acknowledgement is in favour of surgical management around the fourth year for the advantages of a more mature anatomical situation without reducing quality of results. Purpose of early diagnosis and selective therapy in cryptorchidism is to avoid irreversibility of severe histological alteration able to compromise gonadal, especially germinal, function. It is never to forget that the high level of infertility in cryptorchidism can be depending not only on evident alteration in number, motility and morphology of spermatozoa but also on morphofunctional defects escaping from the routine seminal examination. All that is in tight connection with the intrinsic dysmorphism in cryptorchism where the abnormal position of the testis is only a partial aspect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Arterialized penile skin flap: personal technique of reconstruction of the bulbo-membranous urethra].

In bulbar-membranous urethral strictures, the surgical choice treatment should consist on removing the stricture and performing an end to end overlap anastomosis between two flat patent surfaces (Turner-Warwick's technique), whenever possible. When this procedure cannot be used (recurrence, complex or too long strictures), we get different types of tissue in order to create a fitting neo-urethra. To this goal, in the last twenty years we performed, a wide range of urethroplastic techniques (scrotal flap, bladder mucosa free grafts, dermo-epidermal free mesh-grafts). We recently achieved a significant improvement of the post-operative results by an original procedure, which consists in using a very well-vascularized pediculed flap, taken from the complete penile dorsal skin, pulling it to the perineal area, laterally to the cavernous bodies, to be employed for the reconstruction of the neurethra. By this way, we obtain a viable and suitable tissue, reaching even 13 cm in length, so creating a very long segment of neurorethra. A free dermoepidermal mesh-graft should be used to cover the dorsal surface of the penis, in case of enlarged skin uptake. From February 1989 to April 1990, 16 patients affected with complex and relapsed bulbar-membranous urethral strictures, underwent urethroplasty with penile skin island flap. Urethrocistograms and urinary flowmetry performed 3 months from operation demonstrated effective results and all patients referred satisfactory micturation; no fistulas occurred.

Adult↗
PubMed1991

[Venous leakage and role of the suspensory ligament of the penis: anatomo-surgical observations and therapeutic suggestions].

From April 1988 to October 1990 we treated 80 patients by D.D.V. ligation and successive tightening of the cavernous bodies with simultaneous corporo-pubic suspension with four non-absorbable dorsal stiches. In 58 of them, further ligation have not been necessary; the remaining 22 patients had also to be treated with cavernous crura ligation (16 Pts.) and Urettiro-glandular lysis (6 Pts.). The immediate post-operative functional success (satisfactory sexual intercourse), in the first group, was 88%, in the second one was 80%. The 12-months follow up (50 Pts.) has shown a success rate of 77.5. In the technique we propose (corporo-tightening and pubic suspension - C.T.P.S.) there are two advantages: the reduction of the cavernous outflow and the improvement of the erection angle, making coitus easier.

Adult↗
PubMed1991

[Injuries of the urethra and corpora cavernosa].

Authors present a synthetic review on the etiopathogenetic classification of the posttraumatic urethral and cavernosal pathology. Furthermore they propose the current therapeutic assessment adopted at the Institute of Urology of Milan, both in case of urgent management and for elective treatment.

Drainage↗
PubMed1990

Beta-TG and plasma catecholamines levels after sympathetic stimuli in hypertensives and patients with peripheral vascular disease.

The influence of the sympathetic nervous system on platelet functions in vivo is still controversial. The aims of our study were to compare the response to various sympathetic stimuli in normal subjects and in patients with essential hypertension (HT) or peripheral vascular disease (PVD) and to evaluate any correlations among plasma levels of catecholamines, beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4). In basal conditions beta-TG and PF4 values in the HT patients were higher than those observed in the controls of the same age but lower than those of the PVD patients. Although the different sympathetic stimuli (90 degrees tilting, handgrip, treadmill test, bicycle test) caused a significant increase of the plasma epinephrine (E) and norepinephrine (NE) levels, they did not modify the beta-TG and PF4 levels in any of the groups studied. The platelet activation indices, therefore, regardless of the basal values, do not seem to be influenced by sympathetic stimulation.

Adult↗
PubMed1990

Combined radiosurgery and external radiotherapy of intracranial germinomas.

Germinomas are successfully treated with radiation therapy; we have observed six cases that have been stereotactically irradiated by means of a linear accelerator (radiosurgery). In most cases a single dose of stereotactic irradiation effects the reduction of the tumor volume in a few days. External whole brain and, in two cases, spinal irradiation completed the treatment to avoid seeding of tumor cells. The technique and the advantages of this original therapeutical approach to intracranial germinomas are described and discussed.

Adolescent↗
PubMed1990

99mTc complexes of alpha,alpha-disubstituted, alpha-hydroxy carboxylic acids.

99mTc complexes of 2-ethyl-2-hydrobutyric acid, 2-hydroxyisobutyric acid and (+)- and (-)-citramalic acid are readily prepared in high yield and high purity by reduction of 99mTcO4- in the presence of excess ligand. The resulting agents are very stable in vitro, but can undergo some decomposition during chromatographic analysis unless appropriate precautions are taken. Biodistribution studies in rats and dogs show that these new 99mTc agents accumulate primarily in the kidney and urinary bladder.

Animals↗
PubMed1990

Linear accelerator radiosurgery of three-dimensional irregular targets.

Current radiosurgical techniques allow concentration of radiation from external sources into spherical targets. Nonspherical target volumes require a modification of the irradiation technique. Moreover, isodose shaping is sometimes necessary to spare nearby important radiosensitive structures. To meet these prerequisites we have introduced some technical refinements: (1) computer-controlled rectilinear translations of the target in combination with different angular positions of the source and (2) computer-controlled rotations of the target around a vertical axis in combination with different angular positions of the source. The first solution has proven efficient for treating irregular targets, while the second one was employed for focusing the radiation dose inside volumes obtained by rotation of ellipses.

Brain Neoplasms↗
PubMed1990

Modulation of urokinase receptors on human synovial cells and osteoarthritic chondrocytes by diacetylrhein.

On the basis of both 125I-labelled urokinase-like plasminogen activator binding analysis and transmission electron microscopy of an urokinase-gold complex, we have shown the presence of specific receptors for human urokinase on the cell membrane of human synovial cells. By radio-ligand binding experiments we have shown the existence of similar receptors on the surface of human chondrocytes. In both cases the specific binding is attributable to interaction between the receptor and the A chain of the ligand, as previously shown in other cell model systems. Treatment of synoviocytes with 1,8-diacetoxy-anthraquinone-3-carboxylic acid (diacetylrhein) is able to reduce the number of surface urokinase receptors. At the same time the drug can reduce the fibrinolytic activity released into the culture medium of human synovial cells. Preliminary data indicate that chondrocytes from osteoarthritic patients have a larger number of urokinase receptors than chondrocytes of normal patients. Diacetylrhein can restore the receptor number to normal levels; the amount of urokinase in the synovial fluid of ostroarthritic patients is also reduced. We conclude that the use of this drug has the chance to significantly modify the natural history of osteoarthritis.

Anthraquinones↗
PubMed1990

[Cardiovascular reactivity to isometric stress in patients with stable and borderline hypertension and in normotensive subjects. Effects of alpha sympatholytics and beta blocking agents].

Aim of the study was to evaluate blood pressure (BP) and heart rate (HR) variability during isometric handgrip test (IHT) in 20 ambulant non-obese male adults affected by sustained hypertension (SH) WHO I and II, 20 borderline hypertensive (BH) and 20 normotensives (C) of comparable sex, age and BMI. SBP and DBP were assessed by "Random Zero" sphygmomanometer, HR by ECG registration. IHT was performed at 30% of maximal effort for 3 min. IHT was carried out: 1) after 7 days placebo, 2) after 7 days propranolol treatment (80 mg/day) and, following 10 days wash-out, 3) after 7 days prazosin treatment (0.5 mg/day). After placebo IHT caused increases of SBP, DBP and HR values insignificantly different in the 3 groups. After propranolol IHT induced significantly more elevated SBP and DBP increases in SH than in BH or in C. These increases were significantly more elevated in comparison with those observed, in advance, in the same group of SH subjects after placebo. After prazosin treatment SBP increase induced by IHT was, on the contrary, significantly more elevated in BH than in SH or in C. This increase is more significant in comparison with that observed in the same BH group after placebo treatment. As for DBP variations induced by IHT after alpha sympatholytic therapy we have observed that SH subjects show significantly lesser diastolic variations as compared with those obtained in BH or in C groups after this treatment. In conclusion, enhanced IHT induced SBP elevation after propranolol and dampened DBP reactivity after prazosin suggest an overriding alpha stimulation in SH subjects. SBP hyperreactivity induced by IHT after alpha sympatholytic treatment and DBP hyporeactivity after betablockers emphasize the role of beta stimulation in BH individuals. Inhibition of BP reactivity to IHT in C after prazosin suggest that this one is mediated by alpha adrenergic receptors.

Adult↗
PubMed1989

Biodistribution of Tc-99m methoxy-isobutyl-isonitrile (MIBI) in humans.

Hexakis (methoxyisobutilisonitrile) technetium(I), 99mTc-MIBI, has been proposed for myocardial perfusion studies. We have evaluated the biodistribution of this new agent in normal volunteers at rest and after stress. The biodistribution of 99mTc-MIBI is characterized by rapid blood clearance and a consequently early myocardial uptake. The initial intense hepatic activity is cleared into the gallbladder at 1 h after injection, and the best target to non target ratio is observed at 60-90 min after injection. Absorbed radiation dose calculations show that the thyroid is the critical target organ (230 mRad/mCi at rest), presumably because of 99mTc-pertechnetate generated in vivo. Our results indicate that 99mTc-MIBI is a promising tracer for myocardial perfusion imaging.

Adult↗
PubMed1989

Effects of tetroxoprim and sulfadiazine on T lymphocyte proliferation and gamma-interferon production.

The in vitro effects exerted by tetroxoprim and sulfadiazine on T lymphocyte proliferation were evaluated at drug concentrations equal to and twice the plasmatic peak level of each drug. The two drugs did not exert any significant effect on spontaneous and mitogen (PHA) or monoclonal antibody (MAb anti-CD3) induced T lymphocyte proliferation at the studied concentrations, both when tested separately and combined. In addition the two compounds did not significantly interfere in gamma-interferon (IFN-gamma) production.

Adult↗
PubMed1989

Low-grade astrocytomas: treatment with unconventionally fractionated external beam stereotactic radiation therapy.

Fourteen patients with nonoperable low-grade astrocytomas were treated with unconventionally fractionated stereotactic radiation therapy. The target volume was defined with computed tomography (CT) performed under stereotactic conditions. The treatment was carried out with a technique producing multiple noncoplanar arc irradiation, with the center of the target volume placed at the isocenter of the linear accelerator. A total dose of 16-50 Gy was administered in either one fraction or two fractions 8 days apart. The concentration of dose within the target volume allowed reduction of dose absorbed by adjacent critical structures of the intact brain. Patients were followed up for 11-48 months. Twelve of 14 patients had a partial or complete response to treatment, as demonstrated by CT. Stereotactic radiation therapy appears to be effective in the control of small radioresistant cerebral neoplasms, without damaging surrounding healthy tissues.

Adolescent↗